Packaging material made of unbleached kraft paper, bands made therefrom, and methods for their production.

Description

[0001] 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 the base material, wherein the kraft paper is made from at least 90% primary pulp and has a basis weight according to ISO 536:2019 between 65 g / m² and 170 g / m², as well as to a banderole made from such packaging material, a method for producing the same, and to a use of the packaging material.

[0002] Unbleached kraft paper is widely used as packaging material due to its high tear resistance and good stability against moisture and chemicals. Kraft paper, whether bleached or unbleached, is also easily printable, ensuring that consumers can clearly see the necessary information printed directly on the packaging. A typical application for kraft paper, and especially unbleached kraft paper, is its use in manufacturing bags for packaging a wide variety of materials, such as building materials, sharp-edged items, food, toys, and the like. However, the packaging sector is not limited to the form where the goods are completely wrapped in the paper, such as...Instead of fully enclosed bags, it is often possible to simply wrap goods to be packaged or sold in bundles with a ribbon or band. This ribbon typically displays information about the contents, expiration date, and brand names. Such ribbons are frequently used to bundle multiple similar or related items. For example, in the clothing industry, several items, such as multiple T-shirts, socks, or similar products, are often packaged simply by wrapping them with a ribbon or band. The essential characteristic of the packaging material used for such a ribbon is that it protects the contents from damage.The loop tightly encloses the goods to be enclosed so that it cannot be unintentionally pulled down, so that one or more of the products enclosed by the loop cannot fall out, and furthermore, it is ensured that the goods to be enclosed by the loop can be inserted into it without damage, and that, on the other hand, the loop surrounding the goods does not tear or otherwise become damaged during such insertion or subsequent transport, handling, or the like.

[0003] Similarly, it is often necessary to provide tubular packaging materials into which compressible or resilient items must be packed in their most compressed form. This is to minimize the space required for these packages and to ensure that the packaged goods are not unnecessarily compressed and decompressed during transport, which could lead to material fatigue. In this context, it is particularly important that the packaging material is not stressed beyond its elasticity by the tensile stress exerted by the resilient item inside, causing it to tear, or that the tubular packaging material is not damaged when the item is inserted.To date, plastic films or tapes have been considered the most suitable for this purpose, as they can be manufactured in various forms and adapted to specific requirements. For environmental reasons, the aim is to replace plastic packaging as much as possible with packaging made from renewable raw materials, and especially biodegradable materials. Recently, research has intensified to develop specialty papers, particularly kraft papers, that meet a wide range of requirements regarding durability, elasticity, moisture resistance, and other properties, in order to replace plastic packaging.In cases where ring-shaped closed tubes, tapes, or loops must be used as packaging materials, a particular problem arises: for example, paper packaging is produced from a flat sheet of paper, which must be glued or otherwise sealed to form the ring or tube. If this seal is only created after the goods to be packaged have been inserted, the time required for an adhesive to cure or dry, or for a thermoplastic to harden, may be too long for mass production. Therefore, similar to plastic packaging, it is necessary to form this tube, ring, or loop before inserting the products to be enclosed within it. This ensures that products can be placed into such a tube, ring, loop, or tape without damaging it.In order for items to be inserted into the same container, such packaging material or packaging paper must not only have excellent elasticity 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 the items are inserted.

[0004] The present invention therefore aims to provide a packaging material made of unbleached, optionally coated kraft paper that does not tear under high stress, in particular a stress that stretches the paper, in both the longitudinal and transverse directions of the machine and remains sufficiently elastic or resilient over time so that the items packaged therein cannot fall out even after a long time due to a loss of tension or elasticity of the packaging material.

[0005] To solve this problem, the packaging material according to the invention is essentially characterized in that the kraft paper contains at least 90% primary pulp, comprising at least 80%, preferably at least 85%, and in particular at least 88% pulp with a mean 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%, and in particular less than 4.2% fillers, as well as cationic starch and other processing aids; that the primary pulp is present as milled, in particular highly ground pulp with a Schopper-Riegler refining grade according to ISO 5267-1:1999 between 13 °SR and 20 °SR; that the kraft paper has an elongation-at-break ratio MD / CD according to ISO 1924-3:2005 of > 1.1; and a tear length in the machine direction according to ISO 1924-3:2005 of >10 km exhibits a tear resistance index in the transverse direction of the kraft paper according to ISO 1974:2012 of > 16.0 mN.m²< / g and that the kraft paper is coated, if necessary, at least on one side with a coating material.

[0006] Because the packaging material contains at least 90% primary pulp, comprising at least 80%, preferably at least 85%, and in particular at least 88% pulp with a mean 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%, and 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 length distribution of the fiber lengths of the primary pulp used, to achieve excellent homogeneous paper properties in both the machine direction and the transverse direction.Such unbleached kraft paper, due to its strength and the possibility of being (micro)creped in a Clupak machine, can also be used safely and reliably for packaging sharp-edged objects or heavy materials, such as cement or beverage bottles. Furthermore, by containing less than 5%, preferably less than 4.5%, and particularly less than 4.2% (the percentages given 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 obtain a strong yet not excessively stiff unbleached kraft paper in which high percentages of starch, especially cationic starch, can be used due to the lignin and hemicellulose remaining in the kraft paper and the associated high number of negative charges.Since unbleached kraft paper produced in this way is not excessively stiff, but extremely elastic, it is possible, especially when loops, ribbons, bands or tubes are made from this packaging material, to securely and reliably enclose the items packaged therein without fear of them unintentionally slipping out of the packaging material, whereby care must be taken in the production of such tubes, ribbons or loops that the unbleached kraft paper has greater elasticity in the winding direction of the loop than in the transverse direction of the loop.By designing the packaging material in such a way that the primary pulp is contained as ground, in particular high-consistency ground pulp with a Schopper-Riegler refining grade 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. This results in a uniform sheet or a particularly homogeneous kraft paper, in which an optimized combination of fiber flexibility and tear resistance index in the transverse direction can be achieved. It goes without saying that through high- or high-consistency refining, the paper is not only viscous but also viscous.Low-consistency milling of paper allows both the tear length and the air permeability of the paper to be adjusted, although the latter is not important in the present case, especially when coatings are optionally applied, since neither rapid filling of closed bags from the packaging material according to the present invention is to be achieved, nor does the air permeability otherwise have any advantageous or negative properties for packaging made from the packaging material.

[0007] The packaging material can also consist of 100% virgin pulp. By using packaging material, particularly unbleached kraft paper, made from 100% virgin pulp, it is possible to reliably avoid negative influences on the final product that arise, for example, from recycled pulp as well as from pulp obtained from waste paper. In particular, this avoids the reduced strength or elongation at break of the packaging material that is usually caused by waste paper or recycled pulp. In connection with the present invention, it is essential that the elongation at break or the elongation ratio at break, 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 that make it possible to produce tubular packaging.To produce bands or loops in which even heavy or sharp-edged objects can be packaged and / or wrapped and stored for extended periods without fear of tearing or ripping of the unbleached kraft paper or deterioration of the packaging produced with it.

[0008] By ensuring that the unbleached kraft paper of the packaging material has an elongation ratio MD / CD according to ISO 1974:2012 of > 1.1, it is guaranteed that its elongation in the machine direction (MD) is greater than that in the transverse direction, and that the packaging material is therefore not only stretchable 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.

[0009] Since the elongation-at-break ratio MD / CD of the kraft paper, according to ISO 1974:2012, is greater than 1.1, it is ensured that even items with uneven, smooth surfaces can be securely and reliably packaged in this unbleached, optionally coated, kraft paper packaging material. This is because the paper, after returning to its original shape from its expanded form upon insertion, effectively encloses the packaged goods on all sides and is also capable of securely and reliably holding goods with uneven surfaces. At the same time, the elongation is sufficient to allow the products to be inserted into the packaging material, particularly coated kraft paper, without damaging it.The packaging material allows for the insertion of tubular sleeves, and it is furthermore ensured that the paper returns to its original shape after the materials are inserted and stretched, thus tightly enclosing the packaged items. This prevents items from falling out of, for example, tubular or ring-shaped packaging made of the packaging material according to the invention. Furthermore, it has been shown that with an elongation at break (MD / CD) ratio of the kraft paper according to ISO 1974:2012 of > 3, no further improvement in the properties of the packaging material required for packaging heavy items is achievable.

[0010] Because the tear length in the machine direction of the kraft paper is > 10 km according to ISO 1924-3:2005, it is further ensured that the machine strength in the longitudinal direction of the packaging material is so high that, even if, for example, tubular or ring-shaped packaging has been produced from it, inflexible objects can be inserted into the interior of this shaped packaging material without the risk of unintentional tearing of the kraft paper. Furthermore, because the tear resistance index in the transverse direction of the kraft paper is > 16.0 mN / m² / g according to ISO 1974:2012, it is ensured that tearing of a free edge of the packaging material is not a concern even under unintentionally high loads on the edge of the packaging material, and particularly when tubular or ring-shaped packaging is used.Since ring-shaped products made from this packaging material, such as ribbons or bands, do not have to be feared when inserting the goods to be packaged, as this prevents the packaging material from tearing and thus destroying the packaging.

[0011] By designing the packaging material such that the tear resistance index (CD) in the transverse direction of the kraft paper is > 16.0 mN / m² / g according to ISO 1974:2012, the packaging material, consisting essentially of unbleached, optionally coated, kraft paper, can withstand significant stress even at its edges without the risk of tearing or propagation from the edge to the center. This also prevents even a small tear in the packaging material from unintentionally widening.

[0012] In the context of the present invention, the term "packaging material" essentially refers 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.

[0013] According to a further development, the packaging material can also consist of 100% virgin pulp. By making the packaging material, in particular the unbleached kraft paper, from 100% virgin pulp, it is possible to more reliably avoid negative influences on the final product that arise, for example, from recycled pulp as well as from pulp obtained from waste paper. In particular, this avoids the reduced strength or elongation at break of the packaging material that is usually caused by waste paper or recycled pulp. It is essential in connection with the present invention that the elongation at break, in particular, is significantly reduced.The elongation at break, 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 that make it possible to produce tubular or ring-shaped packaging or bands in which even heavy or sharp-edged objects can be packaged and / or wrapped and stored for extended periods without risk of tearing or ripping of the unbleached kraft paper or deterioration of the packaging produced with it.

[0014] By designing the packaging material, as is a further development of the invention, to have a starch content of 0.5% to 2.2% of the kraft paper, particularly 0.7% to 2.0%, it is possible to maintain the excellent mechanical properties of the unbleached kraft paper, the surface smoothness of at least one side of the kraft paper, and to keep the Bendtsen roughness low, thus ensuring excellent printability of this at least one side of the packaging material. In this context, the aim is simultaneously to make only one side, in particular the side facing away from the machine or the "top side" of the paper, correspondingly smooth in order to ensure adhesion to the inside of tubular or ring-shaped packaging.The side facing away from the "top side" is to be made as large as possible from the packaging material according to the present invention in order to prevent the loss of the items packed therein by slipping out as much as possible.

[0015] According to a further development of the invention, the packaging material is designed such that the primary pulp consists of a mixture comprising at least 80% softwood pulp, preferably at least 90% softwood pulp, in particular at least 95% softwood pulp with a mean 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 a mean length-weighted fiber length according to ISO 16065-2:2014 of at least 1.0 mm.The predominant amount of softwood pulp with a mean length-weighted fiber length according to ISO 16065-2:2014 of at least 2.0 mm and the remainder of hardwood pulp with a mean length-weighted fiber length according to ISO 16065-2:2014 of at least 1.0 mm allows the strength properties of at least one side of the unbleached kraft paper to be positively influenced by the softwood pulp and the smoothness by the hardwood pulp. Furthermore, a targeted selection of the pulp composition can provide a packaging material with both excellent mechanical properties, particularly elongation at break, and sufficient smoothness to ensure good printability.Furthermore, such a choice of pulp mixture, in particular the high content of softwood pulp, ensures that an unbleached packaging material produced in this way has a large tear length in the machine direction, thus providing a particularly durable packaging material in which even heavier items can be packaged without the packaging necessarily having a bottom and / or top surface.

[0016] By designing the packaging material, as is a further development of the invention, to have a tensile strength index in the machine direction according to ISO 1924-3:2005 of > 105 Nm / g, preferably at least 115 Nm / g, 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 manufacturing, for example, tubular, loop-shaped, or band-shaped packaging from the packaging material according to the invention, sufficient strength of the packaging material is provided, thus reliably enabling even heavy objects to be fitted into such a loop or band made of the packaging material, and moreover, there is no risk of the material tearing.

[0017] Similarly, in accordance with a further development of the invention, the packaging material has a TEA index in the machine longitudinal direction according to ISO 1924-3:2005 greater than 5.0 J / g, preferably greater than 5.5 J / g. Because the TEA index in the machine longitudinal direction is greater than 5.0 J / g, it is possible to provide a packaging material that is extremely elastic and stretchable without tearing. The TEA index is understood to be the tensile energy absorption index according to ISO 1924-3:2005.

[0018] To reliably prevent tearing or bursting of the packaging material according to the invention from the edges towards the center, the invention is further developed such that the packaging material has a burst 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 burst strength is achieved or increased, among other things, by a combination of the following measures: the use of softwood pulp, a low filler content, and a high proportion of, for example, cationic starch. Furthermore, the milling process, in particular low-consistency milling, also has a positive influence on the burst strength.

[0019] By designing the packaging material, as is a further development of the invention, to have a wet strength index according to ISO 3781:2011 in the machine direction of the kraft paper of at least 14.0 Nm / g, in particular 14.5 Nm / g, and most preferably at least 15.0 Nm / g, it is possible to provide 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 food items are manufactured from the packaging material, contact with condensation, moisture, or a humid environment is unavoidable, so that high wet strength is essential.A high wet strength index is desirable, but without the need for permanent wet strength agents or large quantities thereof in the production of the packaging material, which consists primarily of unbleached kraft paper. The wet strength index according to ISO 3781:2011 in the machine direction can be further improved by applying a coating to one or both sides of the packaging material.

[0020] 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 larger quantities of additives, such as wet-strength agents, which in turn cause problems when recycling the packaging material, which consists essentially 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 consists essentially of unbleached kraft paper, is > 105 Nm / g, a sufficient wet strength can surprisingly be achieved very resource-efficiently without, or only by adding minimal amounts of, wet-strength agents.

[0021] In this context, wet-strength agents are understood to be water-miscible polymer solutions in their processed state, primarily made from polyamines and epichlorohydrin derivatives. While urea-formaldehyde or melamine-formaldehyde-based products are also conceivable as wet-strength agents, they are no longer commonly used due to health concerns. When wet-strength agents react with cellulose fibers, cross-linking forms between the fibers, leading to increased water resistance in the resulting paper. However, this hydrophobic cross-linking prevents the simple or successful recycling of paper treated with these wet-strength agents. Therefore, returning used packaging papers to a pulp cycle is either impossible or only partially feasible through 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 is surprisingly achievable with a kraft paper or packaging material according to the invention.

[0022] According to a further development of the invention, the packaging material is designed such that a coating material selected from a polyolefin is applied to at least one side in an amount corresponding to 1 / 15 to 1 / 6 of the basis weight of the kraft paper. By applying a coating material selected from a polyolefin or polylactic acid (PLA) to at least one side of the packaging material in an amount corresponding to 1 / 15 to 1 / 6 of the basis weight of the kraft paper contained in or forming the packaging material, it is possible, on the one hand, to further improve the wet strength of the packaging material without impairing its excellent mechanical properties. On the other hand, by applying such small amounts of a coating material to at least one side of the packaging material, it can be ensured that loops, rings, tubes, bands, or the like cannot be formed.can be formed from the packaging material by overlapping free end areas of the packaging material and forming a closed ring by heat sealing the at least one thermoplastic polyolefin layer or the polylactic acid layer.

[0023] Finally, by applying an amount corresponding to 1 / 15 to 1 / 6 of the basis weight of the kraft paper to a polyolefin coating material or polylactic acid coating material, it can be ensured that a packaging material produced in this way is both biodegradable and, due to the small amount of polymer, not harmful to the environment.

[0024] By selecting the polyolefin from high-density polyethylene (HDPE), low-density polyethylene (LDPE), or polypropylene (PP), as is a further development of the invention, coatings can be formed that are both stable and do not impair the mechanical properties of the kraft paper forming the base of the packaging material. Polyolefin coating materials with densities in the range of 900 to 950 kg / m³ and softening or melting temperatures between 125 and 150 °C have proven to be particularly suitable in this regard.

[0025] According to a further development of the invention, the packaging material is further developed to form a laminate consisting of several layers of kraft paper and several layers of the coating material. By forming a laminate of several layers of kraft paper and several layers of the coating material, it is possible to provide both resilient and extremely durable packaging materials. Such packaging materials can be used, for example, as packaging straps, particularly as a replacement for plastic straps enclosing packages, boxes, or the like. Furthermore, such laminates can not only be used on existing industrial packaging machines, but due to the particularly high tensile strength of the laminate, it can also be stapled without the risk of the staples tearing out or the laminate tearing due to material weakening.

[0026] In a further development of the invention, the laminate comprises at most 5 layers of kraft paper, such as 4 layers, more favorably 3 layers, preferably 2 layers, and at most 6 layers of coating material, such as 5 layers, more favorably 4 layers, preferably 3 layers. This allows, on the one hand, the production of laminates that are optimally adapted to the thickness requirements of industrial packaging machines. On the other hand, a large number of different strips, bands, loops, or the like can be produced from the laminate using a single basis weight of kraft paper, which in particular reduces downtime and the necessary adjustments to the paper machine. Consequently, the kraft paper forming the basis of the packaging material can be produced more economically.

[0027] According to a further development of the invention, each layer of coating material located between two kraft paper layers comprises an amount corresponding to 1 / 15 to 1 / 9 of the basis weight of the kraft paper, and a layer of coating material forming the outer surface of the laminate comprises an amount corresponding to 1 / 11 to 1 / 6 of the basis weight of the kraft paper. With such a design, the amount of coating material used can be minimized, since each layer of coating material located between two kraft paper layers only needs to ensure the cohesion of the two kraft paper layers and can therefore be formed from a smaller amount of coating material. In contrast, each outer layer of coating material must be sufficiently thick to ensure a secure and durable heat seal of, for example, two ends of the packaging material.

[0028] The invention further aims to form or provide a banderole made of the packaging material according to the present invention, with which it is possible to package or enclose and transport a plurality of heavy, unconnected products without fear of the packaging material tearing.

[0029] To solve this problem, according to the invention a banderole made from the packaging material of the present invention is provided, which is designed in such a way that it is formed from a web of at least one layer of packaging material made essentially of unbleached kraft paper, optionally coated, which is closed in the transverse direction, in particular crimped, glued, preferably twice glued, welded, stapled, sewn or riveted, and that a machine direction of the paper web in the packaging material forms a circumferential direction of the banderole.By forming a single-layer web of packaging material consisting of a closed, in particular crimped, glued, preferably double-glued, welded, stapled, sewn or riveted, essentially unbleached kraft paper, optionally coated, the greater elongation that the unbleached kraft paper exhibits in the machine direction is made available in the circumferential direction of the band, ribbon, loop or tubular packaging, so that, due to the excellent elongation of the packaging material in the machine direction, even a plurality of items, when inserted into the band or into the packaging material glued into a ring, does not tear or further tear the packaging material.Because this makes it possible to enclose multiple items with the band, several similar or different items can naturally be enclosed and held together without requiring packaging that completely surrounds them. By arranging the packaging material in the finished band such that a machine direction of the packaging material forms a circumferential direction of the band, the stretch properties introduced by the manufacturing process of the packaging material in the machine direction can be used to ensure that the items to be packaged...Objects to be enclosed can be inserted into a band that has already been glued into a ring, utilizing the elastic properties of the packaging material, without risk of the band tearing. Due to the elasticity of the packaging material, the objects are held securely in the ring after insertion. Furthermore, a band made from this packaging material, particularly a laminate of this material, can also be used instead of plastic bands, which are used, for example, to seal packages, secure items against loss, and the like.

[0030] By forming the packaging material into a ring, loop, or band that encloses multiple items in the direction of the paper web, it is possible to insert a large number of items into such a band without risk of tearing, either transversely or longitudinally, or at the edges. Furthermore, it goes without saying that such a band represents an extremely paper-efficient packaging method that securely and reliably holds items together.

[0031] By enclosing at least two identical or different items, the band ensures that packages of any size can be formed. These packages can be reliably inserted into the band or tubular product simultaneously, thanks to the MD / CD ratio of the optionally coated kraft paper (according to ISO 1924-3:2005) of > 1.1 to approximately 3 and the transverse tear resistance index (according to ISO 1974:2012) of > 16.0 mN / m² / g, without any risk of the paper edges tearing or fraying. Heavy items, or items with a considerable length or height compared to the band's width, can also be packaged in such a band without the risk of the band tipping over and subsequently tearing.This is because the material properties of the packaging allow the items to be tightly enclosed, meaning that even if one or more items are tilted, there is no risk of the band tearing and subsequently breaking. Such a band can also be used to seal, for example, a cardboard box or similar items.

[0032] The band can be designed such that the majority of items are arranged in several rows, in a circle, or forming a dense pack within the band. With such an arrangement of the enclosed items, 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 several identical foam elements, such as foam cushions or metal or wooden rods, can be arranged inside such a band.

[0033] According to a further development of the invention, the band is designed such that it is subjected to tensile stress by the enclosed items, in particular to a tensile stress that is less than the elongation at break in the machine direction (MD) measured according to ISO 1924-3:2005 of the optionally coated paper web. This tensile load or stress on the items packaged inside such a band ensures that no item unintentionally falls out of the band, which could subsequently compromise the secure retention of the remaining products.

[0034] To ensure sufficient elasticity and resilience of the packaging material, it 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 exhibiting an elongation at break of > 8% in the machine direction have proven their worth in standard packaging materials, such as heavy-duty bags and the like, which are subjected to heavy MD loads. Surprisingly, it has been shown that bands made from such material are able to securely and reliably hold the products inside, thanks to the excellent resilience of this material. There is no risk of the products slipping or falling out of the band, nor is there any risk of the band tearing or ripping when the products are inserted.

[0035] According to a further development of the invention, the band, ribbon, or the like is designed such that it consists of a laminate comprising several layers of kraft paper and several layers of coating material, such as at most 5 layers of kraft paper, for example 4 layers, more preferably 3 layers, preferably 2 layers of kraft paper, and at most 6 layers of coating material, such as 5 layers, more preferably 4 layers, preferably 3 layers of coating material. By using a laminate, the band, ribbon, or loop can be used as a replacement for conventional plastic ribbons without the risk of the laminate tearing. Unintentional separation of a joint between two ends of the laminate is also reliably prevented, regardless of whether the ribbon or band is heat-sealed, stapled, crimped, or otherwise joined together.

[0036] A further objective of the present invention is to provide a method for forming a band from the packaging material according to the invention, whereby the problem with conventional manufacturing methods lies essentially in the fact that, due to appropriate treatments, a paper web generally exhibits greater elongation properties in the machine direction than in the transverse direction. Although isotropic papers are already known which have the same properties in the longitudinal and transverse directions, these can only be produced to a limited extent on large paper machines and, in particular, these papers usually exhibit at least slightly inferior properties in the transverse direction.

[0037] In order to optimally utilize the favorable properties of the packaging material according to the invention in a banderole, the inventive method is designed such that a length of packaging material slightly exceeding the circumference of the banderole to be formed is cut from a web of packaging material consisting essentially of unbleached kraft paper that is unwound longitudinally in the machine direction. The cut length of packaging material is then pivoted by 90°, and the two free edges of the cut length, which run transversely in the machine direction as the web of packaging material is unwound, are folded over each other and sealed to form a tube. A plurality of banderoles are then cut from the sealed tube or prepared for cutting, in particular by perforation, scoring, or marking. Due to the lack of possibility orSince it is economically pointless to make cuts, or a multitude of cuts, into the paper in the longitudinal direction of a moving paper web on a paper machine, the process is essentially carried out as follows: First, a length of packaging material is cut from a moving web, a length that corresponds essentially to the circumference of a band to be produced. A certain excess length can, of course, be included, which must be present as an overlap when the packaging material is subsequently sealed to form a tube or, if applicable, a single band. After cutting off the appropriate length, a tube can either be formed directly from the cut length, in which case the paper is folded so that, in principle, the transverse direction, i.e.,The width of the packaging material forms the circumference of the tube, or the cut piece of packaging material can be turned 90° and subsequently glued, crimped, riveted, sewn, or similarly joined to form a tube. In a final step, it is necessary to cut off appropriate pieces from the formed tube, corresponding to the width of the band. This cutting can be done by cutting, punching, tearing, or similar methods, whereby perforations, marking lines, pre-cut areas, or similar features can be applied beforehand. Depending on the intended use and final application of the band, this is either done directly at the point of production or by the end customer.It makes sense to not separate pieces that form a large number of bands beforehand, since printing is generally easier if larger areas can be printed simultaneously.

[0038] 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 the packaging material by 90° is performed before or after folding over and sealing the two free edges of the cut length that run transversely to the machine when the web of packaging material is unwound. As explained above, it is irrelevant whether the pivoting of the cut length of the packaging material by 90° is performed before or after folding over for sealing the two free edges of the cut length.

[0039] The packaging material according to the invention can, as a further development of the invention suggests, be used as a band or as a strap, and it should be noted that conventional bags and the like could of course also be made from this packaging material, but this only seems sensible for high-performance products due to the special material properties.

[0040] The invention is further explained below with reference to exemplary embodiments and drawings. These show: Fig. 1 a schematic representation of possible ways of combining a packaging material according to the invention with a band or loop; and Fig. 2 a schematic representation of the process flow for the production of a banderole from the packaging material according to the invention.

[0041] In detail, in Fig. 1a) schematically shows a banderole or loop 1, which banderole 1 is designed such that two free ends 2, 3 of the packaging material forming the banderole 1 overlap and at least one connection is formed in the area of ​​the overlap 4.

[0042] With such packaging material, which is designed in particular as a loop or band, it is thus possible to hold a number of identical or differently shaped objects within the band 1 without, for example, having to use additional plastic packaging that extends over the entire package of objects. The area of ​​connection 4 can have any type of connection, such as flat adhesive bonds (see Fig. 1b )), point-like adhesions (see Fig. 1c )), or it can be any type of connection, such as sewing (see Fig. 1dCrimping, large-area gluing, thermal sealing, or similar methods are used. Such a band is then pulled over the objects to be joined, thereby holding them tightly and firmly together due to the material's resilience.

[0043] In Fig. 1b Figure 1 shows a perspective longitudinal view of an endless tube formed from the packaging material according to the invention, which endless tube is intended for forming a plurality of banderoles 1. In the Fig. 1b In the depicted formation, the free ends 2, 3 of the packaging material are again arranged overlapping, and the connection area 4 is fully bonded, as shown by a dashed area. The dashed lines 11 show in Fig. 1b ) possible separation lines for separating individual banderoles 1.

[0044] In Fig. 1c) is a representation of an endless tube made of the packaging material according to the invention in an analogous manner as in Fig. 1b ) shown, where instead of full-surface bonding in the overlap area, four spot-shaped adhesive points, arranged in two staggered rows, were used. It goes without saying that any other type of bonding, be it two separate adhesive lines, one adhesive line, or the like, can of course be chosen. If a single- or double-sided coated packaging material is used, the bonding can preferably be achieved by thermal sealing or welding of the thermoplastic coating.

[0045] In Fig. 1d ), in which there is also 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 schematically indicated by the seam lines 6.

[0046] With such bands 1, it is now possible to package a wide variety of items securely together and, in particular, to ensure that even when packaging heavy items such as metal rods or the like, tearing of the packaging material 8 is prevented. When such a band 1 is pulled over the items to be packaged, especially heavy or hard items, the resilience of the unbleached kraft paper forming it, particularly its elongation at break, tensile strength, and tear resistance index, ensures that if a small tear should occur in the packaging material 8 forming the band 1, it will not tear further. Moreover, the band 1 thus formed contracts sufficiently after stretching to prevent the packaged items from slipping out after the packaging is complete.Furthermore, due to the special design of the packaging material 8, a certain degree of static friction can be exerted on the packaged items, ensuring that the items are held securely inside the band 1 and that slippage of one or more items is reliably prevented. This static friction can be exerted not only by the band 1 itself, but also, for example, by the surface of the packaged items.

[0047] In Fig. 2 , in which the reference numerals of Fig. 1 The process flow for producing a banderole from the packaging material 8 according to the invention is shown schematically.

[0048] In Fig. 2The number 7 denotes a roll of packaging material 8, such as that wound from a paper machine onto a drum during production. The packaging material 8 is unwound from roll 7 in the direction of arrow 9, which also corresponds to the machine direction of the machine on which the packaging material 8 was produced, for example, a paper machine. When a sufficient length of packaging material 8 has been unwound, it is cut along its width, as indicated by dashed line 10. In a second step, this cut length of packaging material 8 is rotated by 90°, as indicated by arrow 11, so that the original machine direction 9 is now oriented transversely to the cut piece of packaging material 8, as again indicated by arrow 9.The cut 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. Depending on the subsequent method of joining the packaging material 8, either a slight excess length is chosen to allow the ends to be glued together, particularly when using packaging material coated with a thermoplastic such as PE or PLA, for thermal sealing, or the circumference length is chosen to be exactly the same as that of the band if the joining is done by crimping, stapling, sewing, or the like. In a third step, a tube is formed from this cut length of packaging material 8, using any conventional tube forming method, as indicated in the figure.In the present case, the tube is shaped such that the free ends 2, 3 of the packaging material 8 overlap each other by a distance or length 4, in order to subsequently be able to glue the free ends 2, 3 together, for example, or even to glue them twice. The free ends of the packaging material 8 are, as shown in the figures... Fig. 1 , designated by reference numerals 2 and 3, and the overlapping piece by 4, as is done, for example, in Fig. 1a As shown. After the packaging material 8 has been glued, the tube produced in this way can either be printed on 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.

[0049] It goes without saying that the second step of the process, folding the packaging material 8 by 90°, can also be carried out after tube forming. In any case, the packaging material 8 must be joined together along the edges 2, 3 in order to have the favorable material properties resulting from the machine direction of the kraft paper production available in the circumferential direction of a finished banderole 1.

[0050] Regarding optional process steps, such as printing, perforating, or the like, it should be noted that these can be carried out before or after each step following the separation of the web of packaging material 8 from the drum. For example, 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.

[0051] The band or loop 1 can be not only monochrome, but also printed in multiple colors, bearing company names, logos, and the like. Furthermore, it can have a single-sided or double-sided coating to, for example, improve the moisture resistance of the packaging material 8. Finally, it can also consist of more than one layer of unbleached kraft paper. Thus, a laminate can be formed consisting of more than one layer of kraft paper, with a layer of coating material sandwiched between each layer of kraft paper and an outer layer of coating material on each layer. The basis weights of the individual coating material layers and the basis weights of the individual kraft paper layers can also differ from one another.It should be noted that in this case the essential properties of the banderole 1 must not be changed and neither the elongation at break nor the burst strength, the tear length, etc. are changed compared to a possibly coated single-layer paper banderole.

[0052] Finally, it goes without saying that a band 1 according to the invention can be used not only to hold together heavy and hard objects or plastic containers, but also, for example, to wrap socks, to connect foodstuffs such as bananas, zucchini, cucumbers, or the like, or to seal cardboard boxes. Goods or foodstuffs packaged in cans, boxes, and the like can also be joined together to form bundles.

[0053] Furthermore, the invention will be explained in more detail below using exemplary embodiments. Example 1: Production of a packaging material based on unbleached kraft paper with a basis weight of 82 g / m² Process description:

[0054] An unbleached pulp consisting of 100% primary softwood pulp (a mixture of spruce and pine) with a kappa number of 51 was first subjected to high-consistency refining at a refining rate of 230 to 240 kWh / t, resulting in a pulp fineness of 17 °SR after high-consistency refining. This pulp was then subjected to low-consistency refining at a refining rate of 90 to 100 kWh / t. The following additives were added in the constant section of the paper machine. The pH was adjusted to 6.8 to 7.0 using aluminum sulfate. Cationic starch with a cationization degree DS of 0.03 was added at a rate of 17 kg / t of dry paper. Alkenyl succinic anhydrides were used as sizing agents at a rate of 0.8 kg / t of dry kraft paper, and PAAE was used as a wet strength agent at a rate of 10 kg / t. No fillers were added.The consistency of the pulp at the headbox was 0.19%. Dewatering was carried out on a Foudrinier wire section and with a three-nip press section, 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). Before the still-moist paper was fed to the Clupak unit, it underwent contact drying, conventional drying with hot air at 167 °C, then pre-drying in a slalom drying section, and finally treated in a Clupak unit at a differential speed of -7.9%, and ultimately dried to a final residual moisture content of 7.5%.

[0055] Kraft paper can be used as such for the production of ribbons, bows or bands, and the paper properties described in the following table were measured in this kraft paper.

[0056] The kraft paper produced in this way had the following properties: Table 1: Paper properties standard Unit Direction Result Grammar 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 Train demolition work ISO 1924-3:2005 J / m²< MD 578 Train demolition work ISO 1924-3:2005 J / m²< 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 / m²< MD 14,2 Tear resistance index ISO 1974:2012 mN.g / m²< CD 16,1 Ratio of elongation at break ISO 1924-3:2005 - MD / CD 1,12 Breaking length ISO 1924-3:2005 km MD 11,06 Example 2: Production of a packaging material based on unbleached kraft paper with a basis weight of 130 g / m² Process description:

[0057] 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 rate of 190 to 210 kWh / t, resulting in a pulp fineness of 19 °SR after high-consistency refining. This pulp was then subjected to low-consistency refining at a refining rate of 70 to 80 kWh / t. Additives were added in the constant section of the paper machine. The pH was adjusted to 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-run paper, and alkenyl succinic anhydrides were used as sizing agents at a rate of 0.8 kg / t of dry-run kraft paper. Glycoxalated PAM was used as a wet-strength agent at a rate of 10 kg / t of dry-run kraft paper.No fillers were added. The consistency of the pulp at the headbox was 0.23%. Dewatering was carried out on a Foudrinier wire section and with a press section with three nips, one of which could be a shoe press, with the line pressure at the three nips being 60 kN / m, 90 kN / m, and 500 kN / m (in the shoe press). The kraft paper is pre-dried and then processed in a Clupak unit at a differential speed of -8.6% and finally dried to a final moisture content of 7.5%.

[0058] Kraft paper can be used as such, and the paper properties described in the following table were measured using this paper.

[0059] The kraft paper produced in this way had the following properties: Table 2: Paper properties standard Unit Direction Result Grammar 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 Train demolition work ISO 1924-3:2005 J / m²< MD 871 Train demolition work ISO 1924-3:2005 J / m²< 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 / m²< MD 12,1 Tear resistance index ISO 1974:2012 mN.g / m²< CD 19,3 Ratio of elongation at break ISO 1924-3:2005 - MD / CD 1,21 Breaking length ISO 1924-3:2005 km MD 12,7 Example 3: Production of a packaging material based on unbleached kraft paper with a basis weight of 130 g / m² Process description:

[0060] 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 rate of 190 to 210 kWh / t, resulting in a pulp fineness of 19 °SR after high-consistency refining. This pulp was then subjected to low-consistency refining at a refining rate of 70 to 80 kWh / t. Additives were added in the constant section of the paper machine. The pH was adjusted to 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-run paper, and alkenyl succinic anhydrides were used as sizing agents at a rate of 0.8 kg / t of dry-run kraft paper. Glycoxalated PAM was used as a wet-strength agent at a rate of 10 kg / t of dry-run kraft paper.No fillers were added. The consistency of the pulp at the headbox was 0.23%. Dewatering was carried out on a Foudrinier wire section and with a press section with three nips, one of which could be a shoe press, with the line pressure at the three nips being 60 kN / m, 90 kN / m, and 500 kN / m (in the shoe press). The kraft paper is pre-dried and then processed in a Clupak unit at a differential speed of -8.6% and finally dried to a final moisture content of 7.5%.

[0061] Kraft paper can be used as such, and the paper properties described in the following table were measured using this paper.

[0062] The kraft paper produced in this way had the following properties: Table 3: Paper properties standard Unit Direction Result Grammar 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 Train demolition work ISO 1924-3:2005 J / m²< MD 871 Train demolition work ISO 1924-3:2005 J / m²< 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 / m²< MD 12,1 Tear resistance index ISO 1974:2012 mN.g / m²< CD 19,3 Ratio of elongation at break ISO 1924-3:2005 - MD / CD 1,21 Breaking length ISO 1924-3:2005 km MD 12,7 Example 4: Production of a packaging material based on unbleached kraft paper with a basis weight of 161 g / m² Process description:

[0063] Unbleached pulp consisting of 100% primary softwood pulp with a kappa number of 46 was first subjected to high-consistency refining at a refining rate of 210 to 220 kWh / t, resulting in a pulp fineness of 18 °SR. This pulp was then subjected to low-consistency refining at a refining rate of 70 to 85 kWh / t. In the constant section of the paper machine, the additives were added. The pH was adjusted to 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, and alkenyl succinic anhydrides were used as sizing agents at a rate of 0.8 kg / t of dry kraft paper. Talc was added as a filler at a rate of 2 kg / t of dry kraft paper. The pulp consistency at the headbox was 0.25%.Dewatering took place on a Foudrinier screen section, similar to a press section with three nips, where the line pressure at the three nips was 60 kN / m, 80 kN / m, and 80 kN / m respectively. The kraft paper was pre-dried, then fed into the Clupak system and subjected to a differential speed of -10.9%, after which it was finally dried to a final residual moisture content of 8%.

[0064] The kraft paper can be used as such, and the paper properties described in the following table were measured using this kraft paper.

[0065] The paper produced in this way had the following properties: Table 3: Paper properties standard Unit Direction Result Grammar 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 Train demolition work ISO 1924-3:2005 J / m²< MD 1007 Train demolition work ISO 1924-3:2005 J / m²< 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 / m²< MD 12,7 Tear resistance index ISO 1974:2012 mN.g / m²< CD 20,6 Ratio of elongation at break ISO 1924-3:2005 - MD / CD 1,41 Breaking length ISO 1924-3:2005 km MD 12,1

[0066] 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 in particular subjected to a coating treatment, such as a dispersion coating treatment with a thermoplastic like HDPE, LDPE, PLA, or PP. However, such further treatments do not alter, and in particular do not degrade, the essential properties of the packaging material, such as elongation at break, Bendtsen roughness, tear length, tear resistance index, and tensile strength index. If a loop or band is manufactured from the packaging material, care must be taken to ensure that the packaging material is arranged so that the original machine direction is such that, under tensile stress, the band undergoes a diameter increase or elongation of up to 20%.A loop is made possible. The method of joining the free ends of the packaging material forming the loop or band can be modified by applying a coating, either on one or both sides of the band. In such cases, the free ends are typically heat-sealed. Without a coating, the free ends can be joined by gluing, stapling, crimping, sewing, or similar methods. For packaging material coated on one side, a connection using hot melt adhesive, hot-melt adhesive, or similar methods may also be used. For packaging material coated on both sides, a direct bond between the two coating layers is particularly suitable, which can be achieved with minimal time and effort.

[0067] Multi-layer packaging materials are preferably formed as laminates consisting of at least one kraft paper layer, preferably several kraft paper layers and at least two coating layers consisting of a polyolefin, in particular HDPE, LDPE or PP or PLA.

[0068] Example 5 shows a laminate consisting of an unbleached kraft paper layer (KP) with a basis weight of 120 g / m² and an outer coating layer of HDPE with a basis weight of 15 g / m² on both surfaces of the base paper. The kraft paper was produced as described in Example 3. An extrusion coating process was used. The resulting laminate thus has the following structure: 15 g / m² HDPE / 120 g / m² KP / 12 g / m² HDPE.

[0069] The laminate produced in this way had the properties described in the following table. Table 4 Paper properties standard Unit Direction Result Grammar ISO 536:2019 g / m²< 150 Tensile strength ISO 1924-3:2005 kN / m MD 12,5 Tensile strength ISO 1924-3:2005 kN / m CD 5 Elongation at break ISO 1924-3:2005 % MD 12,5 Elongation at break ISO 1924-3:2005 % CD 9,4 Tear resistance ISO 1974:2012 mN MD 1300 Tear resistance ISO 1974:2012 mN. CD 2000 WVTR (23°C / 50% RH)* ASTM1249 g / m² / 24h MD 3 *WVTR test climate 38 °C / 100% RH

[0070] Example 6 shows a laminate consisting of three layers of kraft paper (KP), each with a basis weight of 120 g / m², and each layer has an outer coating layer of LDPE with a basis weight of 15 g / m², as well as an LDPE coating sandwiched between two kraft paper layers with a basis weight of 12 g / m². The kraft paper was produced as described in Example 3. An extrusion coating process was used. The resulting laminate thus has the following structure: 15 g / m² LDPE / 120 g / m² KP / 12 g / m² LDPE / 120 g / m² KP / 12 g / m² LDPE / 120 g / m² KP / 15 g / m² LDPE

[0071] The laminate produced in this way had the properties described in the following table. Table 5 Paper properties standard Unit Direction Result Grammar ISO 536:2019 g / m²< 414 thickness ISOP 534:2012-02 µm ~430 Tensile strength ISO 1924-3:2005 kN / m MD 39,4 Tensile strength ISO 1924-3:2005 kN / m CD 15 Elongation at break ISO 1924-3:2005 % MD 12,9 Elongation at break ISO 1924-3:2005 % CD 9,4 Burst strength ISO 9895:2008 kPa 2442 Tear resistance ISO 1974:2012 mN MD 4680 Tear resistance ISO 1974:2012 mN. CD 7200 WVTR (23°C / 50% RH)* ASTM1249 g / m² / 24h MD 3 *WVTR test climate 38 °C / 100% RH

[0072] Furthermore, it is possible to replace one or all of the polyolefin or polylactic acid layers sandwiched between two paper layers with an adhesive, thereby creating a strong bond between the individual layers forming the laminate. In this case, however, it is essential that the two outer coating layers are made of a polyolefin or PLA.

[0073] A strap made from such a laminate could be used on conventional strapping machines and, more importantly, could be used to secure and package heavy and bulky objects without the risk of the strap breaking. A strap made from such a laminate could therefore be used as a replacement for conventional strapping made entirely of plastic.

Claims

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 the kraft paper 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 beaten cellulose having a Schopper-Riegler degree of beating according to ISO 5267-1:1999 between 13 °SR and 20 °SR, that the packaging material has a strain ratio MD / CD of the kraft paper at break 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, a tear index in the cross direction of the kraft paper according to ISO 1974:2012 is >16.0 mN.m2 / g and that the kraft paper is optionally coated on at least one side with a coating material.

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 2, characterized in that it has a starch content of 0.5 % to 2.2 % of the paper, in particular 0.7 % to 2.0 %.

4. Packaging material (1) according to Claim 1, 2 or 3, 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.

5. Packaging material (1) according to one of Claims 1 to 4, 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.

6. Packaging material (1) according to one of Claims 1 to 5, 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.

7. Packaging material (1) according to one of Claims 1 to 6, characterized in that it has a wet strength index according to ISO 3781:2011 in the machine direction of the kraft paper of at least 14.0 Nm / g, in particular 15.2 Nm / g, particularly preferably at least 15.5 Nm / g.

8. Packaging material (1) according to one of Claims 1 to 7, characterized in that on at least one side a coating material selected from a polyolefin or polylactic acid (PLA) in an amount corresponding to 1 / 15 to 1 / 6 of the grammage of the kraft paper, is applied.

9. Packaging material (1) according to one of Claims 1 to 8, characterized in that the polyolefin is selected from high-density polyethylene (HDPE), low-density polyethylene (LDPE), or polypropylene (PP).

10. Packaging material (1) according to one of Claims 1 to 9, characterized in that it forms a laminate consisting of several layers of kraft paper and several layers of coating material.

11. Packaging material (1) according to Claim 10, characterized in that the laminate has at most 5 layers of the kraft paper, such as 4 layers, more favourably 3 layers, preferably 2 layers of the kraft paper and at most 6 layers of the coating material, such as, for example, 5 layers, more favourably 4 layers, preferably 3 layers of the coating material.

12. Packaging material (1) according to Claim 11, characterized in that each layer of coating material located between two layers of kraft paper has an amount corresponding to 1 / 15 to 1 / 9 of the grammage of the kraft paper and a layer forming an outer side of the laminate of the coating material has an amount that corresponds to 1 / 11 to 1 / 6 of the grammage of the kraft paper.

13. Sleeve (1) made from a packaging material (1) according to one of Claims 1 to 12, characterized in that it is formed from an optionally coated, at least single-layer web of the packaging material, that is closed, in particular crimped, glued, preferably double-glued, welded, stapled, sewn or riveted in the cross direction, substantially made of unbleached kraft paper, and that a machine direction of the paper web in the packaging material forms a circumferential direction of the sleeve.

14. Sleeve (1) according to Claim 13, 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 optionally coated paper web.

15. Sleeve (1) according to Claim 13 or 14, characterized in that the elongation at break in the machine direction (MD) measured according to ISO 1924-3:2005 of the packaging material is >8 %.

16. Sleeve (1) according to one of Claims 13, 14 or 15, characterized in that it is formed from a laminate consisting of several layers of kraft paper and several layers of coating material, such as at most 5 layers of kraft paper, for example 4 layers, more preferably 3 layers, preferably 2 layers of the kraft paper and at most 6 layers of the coating material, such as, for example, 5 layers, more favourably 4 layers, preferably 3 layers of the coating material.

17. Method for forming a sleeve from a packaging material according to one of Claims 1 to 12, 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.

18. Method according to Claim 17, 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.

19. Use of a sleeve (1) produced from the packaging material according to one of Claims 1 to 16 for tightly enclosing a plurality of objects that are the same or different from one another.