Stretchable packaging material

Abstract

Disclosed herein is a method of making a stretchable packaging material, the method comprising: making a cellulosic layer from a refined wood pulp, where the refined wood pulp has been refined to a refinement system of at least about 70 DEG SR; and subjecting the cellulosic layer to a wet creping process. Also disclosed herein is a stretchable packaging material capable of being manufactured by the method, the material comprising a cellulosic layer.

Description

[0001] This disclosure relates to stretchable packaging materials comprising paper and methods for preparing the same. Background Technology

[0002] In industrial environments, goods are typically transported on pallets. To secure the goods to each other, they are usually wrapped in a plastic film, sometimes called stretch wrap. The plastic film is typically a copolymer of LLDPE and α-olefins, but other polymers such as (pure) PE and PVC can also be used. Each pallet requires a significant amount of plastic wrap—it is estimated that each pallet load requires 41 m³, or approximately 0.5 kg, of plastic.

[0003] There is a growing desire to move away from plastic stretch wrapping materials. Many other materials have been considered, including paper. Paper's advantages lie in its ease of recycling and sustainable sourcing. However, paper's disadvantages include its generally limited stretchability and potentially poor tensile strength, both of which make it unsuitable for stretch wrapping. Some previous applications, such as US2020 / 0407089, have mentioned the use of crepe paper as a possible wrapping material. US2020 / 0407089 describes a crepe paper for wrapping pallets produced using a dry creping process. However, the inventors have found that while crepe paper has a higher elongation than some papers, its elongation is still relatively low compared to plastic films, and its tensile strength is also poor. Therefore, it is not truly suitable for industrial pallet wrapping machines specifically designed for plastic stretch wrapping materials. Using this material would require a new machine or a significant modification to existing wrapping machines designed for plastic stretch wrapping.

[0004] The goal is to create a recyclable alternative to plastic film with elongation and tensile strength very close to that of plastic film, so that it can be used on existing pallet wrapping machines without major modifications. Summary of the Invention

[0005] In a first aspect, a method for manufacturing stretchable packaging material is provided, the method comprising: A cellulose layer is made from refined wood pulp, wherein the refined wood pulp has been refined to a degree of at least about 70°SR; and The cellulose layer is subjected to a wet wrinkling process.

[0006] In the second aspect, a stretchable packaging material is provided, which can be prepared using the method of the first aspect.

[0007] In the third aspect, stretchable packaging materials are provided, including raw base paper; The longitudinal breaking elongation of the base paper is at least about 8%, optionally at least about 10%, optionally at least about 12%, optionally at least about 14%; and The longitudinal tensile strength of the base paper is at least about 10 N / 15 mm. The base paper may be or contain a cellulose layer that can be prepared in the first aspect. The stretchable packaging material may be waterproof, and optionally, the base paper has been treated with a hydrophobic substance, such as impregnation with a hydrophobic substance as described herein.

[0008] In the third aspect, stretchable packaging materials, including base paper, are also provided; The longitudinal breaking elongation of the base paper is at least about 14%; and The longitudinal tensile strength of the base paper is at least about 10 N / 15 mm. The base paper may be or contain a cellulose layer that can be prepared in the first aspect.

[0009] In the third aspect, stretchable packaging materials, including base paper, are also provided; The longitudinal breaking elongation of the base paper is at least about 8%, optionally at least about 10%, optionally at least about 12%, optionally at least about 14%; and The longitudinal tensile strength of the base paper is at least about 10 N / 15 mm, and the stretchable packaging material is waterproof. Optionally, the base paper has been treated with a hydrophobic substance, such as impregnation with a hydrophobic substance, which may be, as described herein, optionally, a plant wax, which may include soybean wax. The base paper may be or contain a cellulose layer that can be prepared in the first aspect.

[0010] In the third aspect, stretchable packaging materials, including base paper, are also provided; The longitudinal breaking elongation of the base paper is at least about 8%, optionally at least about 10%, optionally at least about 12%, optionally at least about 14%; and The longitudinal tensile strength of the base paper is at least about 10 N / 15 mm, and the stretchable packaging material is waterproof. Optionally, the base paper has been impregnated with a hydrophobic substance comprising plant wax and a cationic emulsifier, wherein the plant wax may include soybean wax. The base paper may be or comprise a cellulose layer that can be prepared in the first aspect.

[0011] In the fourth aspect, methods for packaging objects are provided, including: The object is spirally wrapped with a stretchable packaging material according to the second or third aspect.

[0012] In the fifth aspect, equipment for packaging objects is provided, including: A device for wrapping a load with a stretchable packaging material, the device comprising a packaging material support; and A stretchable packaging material mounted on the packaging material support, wherein the stretchable packaging material is a material according to the second or third aspect. Attached Figure Description

[0013] Figure 1 A stretchable packaging material for bundling objects, as described herein, is illustrated schematically. Detailed Implementation

[0014] The optional and preferred features of each aspect are described below. Unless otherwise stated, any feature may be used in combination with any other feature and any aspect.

[0015] In a first aspect, a method for manufacturing stretchable packaging material is provided, the method comprising: A cellulose layer is made from refined wood pulp, wherein the refined wood pulp has been refined to a degree of at least about 70°SR; and The cellulose layer is subjected to a wet creping process to produce paper, which may be referred to herein as base paper, crepe paper, or stretched paper.

[0016] Wood pulp Wood pulp and base paper made from wood pulp preferably contain softwood fibers. Preferably, the refined wood pulp and base paper have a solids content (i.e., the content of solids other than water) of at least 50 wt% softwood, optionally at least 60 wt% softwood, optionally at least 70 wt% softwood, optionally at least 80 wt% softwood, optionally at least 90 wt% softwood, or optionally at least 95 wt% softwood. Other wood fibers may also be present, including hardwood fibers. Hardwood fibers may be selected from poplar, birch, beech, oak, maple, eucalyptus, and gum arabic. Optionally, the wood pulp contains 10 wt% or less hardwood, optionally 5 wt% or less hardwood, optionally 1 wt% or less hardwood, or optionally no hardwood.

[0017] Wood pulp and base paper made from wood pulp may contain 20 wt% or less of non-wood materials, such as mineral fillers, optionally 10 wt% or less of non-wood materials, optionally 5 wt% or less of non-wood materials, optionally 3 wt% or less of non-wood materials, optionally 2 wt% or less of non-wood materials. Mineral fillers include calcium carbonate, talc, clays such as kaolin, titanium dioxide, zinc oxide, and calcium sulfate.

[0018] The cork can be selected from first-grade and second-grade pulp. The first-grade pulp is selected from Canadian NBSK, and the second-grade pulp is selected from Scandinavian NBSK (sometimes called Nordic NBSK). NBSK refers to Northern Bleached Cork Kraft Pulp. The pulp and base paper can contain both Canadian NBSK and Scandinavian NBSK. Scandinavian NBSK can contain one or both of pine and spruce, optionally in a weight ratio of about 1:10 to 10:1, optionally 5:1 to 1:5, optionally 5:1 to 1:1, optionally about 7:3. Scandinavian NBSK can also contain one or both of Scottish pine and Norway spruce, sometimes in a weight ratio of about 1:10 to 10:1, optionally 5:1 to 1:5, optionally 5:1 to 1:1, optionally about 7:3. Canadian NBSK may contain black pine, optionally white spruce, and may also contain wood fibers selected from the following trees: redwood, Douglas fir, hemlock, and larch.

[0019] The softwood pulp may include a first wood pulp, which may be Canadian NBSK, having a fiber length of at least 2.5 mm, optionally at least 2.6 mm, optionally at least 2.7 mm, optionally at least 2.8 mm, and optionally at least 2.9 mm. The first wood pulp (which may be Canadian NBSK) may include Canadian NBSK with fiber lengths of 2.5 mm to 4.2 mm, optionally 2.6 mm to 4.0 mm, and optionally 2.7 mm to 3.5 mm. Fiber length may be measured according to FS5 ISO 16065-2.

[0020] The softwood pulp may include a second wood pulp, which may be Scandinavian NBSK, containing fibers shorter than the second wood pulp, with a fiber length of 1.8 mm to 3 mm, optionally 1.8 mm to 2.5 mm, optionally 1.9 mm to 2.5 mm. Fiber length may be measured according to FS5 ISO 16065-2.

[0021] The first wood pulp (which may be Canadian NBSK) and the second wood pulp (which may be Scandinavian NBSK) may be present in the wood pulp and base paper in a weight ratio of 1:4 to 4:1, optionally 4:1 to 1:1, optionally 3:1 to 1:1, optionally 80:20 to 60:40, optionally about 70:30. The inventors of this invention have discovered that the combination of softwood, particularly Canadian NBSK and Scandinavian NBSK, facilitates the production of paper with desired tensile and tensile strength.

[0022] refined In the process of preparing the cellulose layer, the wood pulp is refined. Wood pulp refining refers to the mechanical treatment of the fibers while they are suspended in a liquid such as water. Refining can be carried out in a refining machine, which can be selected from conical refining machines and disc refining machines. A disc refining machine has two opposing discs, and the wood pulp passes between the two discs. Each disc has opposing surfaces (i.e., the surfaces facing the other disc) with strips or teeth protruding from its surface and facing the other disc. During operation, one disc rotates relative to the other, and the wood pulp passes between the two discs (and between the strips or teeth on the discs). A conical refining machine is similar to a disc refining machine, except that its rotating part is conical rather than disc-shaped. Relative rotation can be achieved by one disc (or cone) rotating while the other disc (or cone) remains stationary, or by the two discs (or two cones) rotating in opposite directions. The wood pulp can be passed through one or more refining machines to achieve the desired level of refinement. Optionally, the wood pulp can be processed by multiple refining machines arranged in series.

[0023] Refining can (i) increase the water content in wood cells, (ii) cause fibrillation, thereby increasing the surface area of ​​the fibers, and (iii) cause the peeling of the wood cell walls.

[0024] The inventors of this invention have discovered that refining the pulp to a relatively high degree can improve the elongation and tensile strength of the paper. Preferably, the wood pulp is refined to a refinement of at least about 70°SR, optionally at least about 75°SR, optionally at least about 80°SR, and optionally at least about 85°SR. Preferably, the wood pulp is refined to a refinement of 70°SR to 95°SR, optionally 75°SR to 95°SR, optionally 75°SR to 90°SR, optionally 80°SR to 90°SR, and optionally about 85°SR. "SR" stands for Schopper-Riegler, the Schopper-Riegler test used to measure the abrasiveness of a suspension of paper fibers in water. The refinement degree can be determined by the Schopper-Riegler test and measured according to the procedure described in ISO 5267 / 1-1:1999. The refined wood pulp may contain 2 wt% to 5 wt% solids (the remaining weight percentage being water).

[0025] Cellulose layers (also known as paper or base paper) can be formed from wood pulp in a papermaking machine.

[0026] Formation of cellulose layer After refining, the refined wood pulp can be formed into a cellulose layer (i.e., a paper layer) in a paper machine and undergo wet creping. The paper machine can be a two-wire paper machine. The paper machine can have several sections: a forming section, a press section, and a drying section. In the forming section, the pulp is applied to a forming cloth so that water in the pulp can be drained; the forming cloth can contain a metal or polymer material. If desired, the refined pulp can be diluted so that it contains 0.3 wt% to 1 wt% solids when applied to the forming cloth, optionally containing about 0.3 wt% to 0.7 wt% solids. In the forming section, some of the water in the pulp passes through the forming cloth, leaving a wet cellulose layer on the forming cloth. In the press section, the cellulose layer can pass between one or more pairs of rolls, optionally between two or more pairs of rolls, optionally between three or more pairs of rolls. This allows more water to be squeezed out of the cellulose layer. In the drying section, heat is applied to the cellulose layer to promote water evaporation. Heat can be applied via heated rolls, sometimes referred to as drying rolls or drying tanks. Wet creping is preferably performed in the press or drying section, provided that the creping is wet creping, i.e., the paper contains the minimum amount of water as described herein at the time of creping. Wet creping can be performed on one of a pair of rolls immediately adjacent to the drying section in the press section; therefore, if there are three pairs of rolls in the press section, wet creping will be performed on one of the third pair of rolls. The paper machine may have a post-treatment section, for example, to treat the cellulose layer with a substance, such as coating one or both sides of the cellulose layer with a coating substance (which may be a sizing substance and / or a hydrophobic substance), or impregnating the cellulose layer with a hydrophobic substance. The post-treatment section may include a sizing machine.

[0027] wet wrinkling The creping process is the compression of a cellulose layer in the paper machine along its direction of travel. This causes the cellulose layer to wrinkle or crease. This is achieved by a doctor blade (sometimes called a creping doctor blade). The doctor blade can be arranged parallel to the axis of the roll or perpendicular to the direction of travel of the conveyor belt carrying the cellulose layer, extending across substantially the entire width of the paper, or at least the entire width (perpendicular to the direction of travel of the cellulose layer in the paper machine). The roll can be a roll or a conveyor belt in the press or drying section of the paper machine.

[0028] A wet creping process can be considered as a process in which the dry content (i.e., content other than water) of the cellulose layer, measured immediately before creping, is 80 wt% or less, optionally 70 wt% or less, optionally 60 wt% or less, optionally 50 wt% or less, optionally 40 wt% or less. In other words, a wet creping process can be considered as a process in which the moisture content (i.e., water content or content other than dry solids) of the cellulose layer, measured immediately before creping, is 20 wt% or more, optionally 30 wt% or more, optionally 40 wt% or more, optionally 50 wt% or more, optionally 60 wt% or more.

[0029] Optionally, the wet creping process can be such that the dry content (i.e., content other than water) of the cellulose layer, measured immediately before creping, is 80 wt% to 10 wt%, optionally 70 wt% to 10 wt%, optionally 60 wt% to 10 wt%, optionally 50 wt% to 10 wt%, optionally 80 wt% to 20 wt%, optionally 70 wt% to 20 wt%, optionally 60 wt% to 20 wt%, optionally 50 wt% to 20 wt%, optionally 80 wt% to 30 wt%, optionally 70 wt% to 30 wt%, optionally 60 wt% to 30 wt%, optionally 50 wt% to 30 wt%, optionally 40 wt% to 30 wt%, optionally about 35 wt%.

[0030] After wet creping, the cellulose layer can be dried, for example, by conveying it to the drying section of a paper machine. The cellulose layer can be conveyed to the drying section via a drying felt (or, if creping is performed in the drying section, it continues to be conveyed within the drying section). The drying felt can be in a slalom configuration with multiple heated rollers (e.g., such that on one roller, the cellulose layer is in direct contact with the heated roller, and on the next roller, the drying felt is in direct contact with the heated roller, and vice versa, then alternately from one roller to another). The drying felt can comprise monofilament or multifilament fabric. The drying felt can be a porous mesh made of a non-metallic material (e.g., polymers and / or glass). The drying felt can be a nonwoven or woven material. The polymer material of the drying felt can be selected from polyester, nylon, or acrylic materials. In multifilament fabrics, the filament material can be selected from a variety of materials selected from nylon, glass fiber, and acrylic polymers. The cellulose layer is conveyed at a suitable speed and tension to ensure that it is not torn or otherwise damaged during the drying process. Lower tension helps maintain the tensile and tensile strength properties of the cellulose layer.

[0031] The drying section can be a part where the cellulose layer is heated to achieve water evaporation. Heat can be applied by heated rollers (sometimes called drying drums or drying tanks), which can be Yankee dryers. The heated rollers themselves can also be heated by steam, so they can also be steam drying cylinders.

[0032] After the cellulose layer is dried, it can be wound into a roll, which may be referred to as a reel. The cellulose layer or paper reel is then loaded into a post-processing device, where it is unwound and treated as needed (e.g., applying a surface sizing agent to one or both sides of the cellulose layer (this sizing agent may include hydrophobic polymers and / or suitable minerals, such as alkyl ketone dimers, latex, and / or kaolin) to provide moisture / water resistance). It is then wound back into a roll or reel for storage. Before or during post-processing, it can be cut to desired widths as needed. The creped and dried cellulose layer may be referred to as base paper.

[0033] This method may include impregnating a cellulose layer with a hydrophobic substance (e.g., plant wax) after a wet creping process, preferably after drying. The hydrophobic substance may be in the form of an aqueous emulsion and optionally contains a cationic emulsifier. The impregnation method may include applying the hydrophobic substance using a sizing machine. The method may include feeding a wet-creped and dried cellulose layer into a sizing machine, impregnating the cellulose layer with the hydrophobic substance in the sizing machine, and preferably applying the hydrophobic substance in the form of an aqueous emulsion via the sizing machine. If the hydrophobic substance is applied in the form of an aqueous emulsion, the cellulose layer may be dried after impregnation, for example, at an elevated temperature. This will be described in more detail below in conjunction with waterproof stretchable packaging materials.

[0034] Stretchable packaging materials In a second aspect, a stretchable packaging material capable of being manufactured using the method of the first aspect is provided. The cellulose layer (which can be manufactured using the method of the first aspect) may be referred to as paper or base paper, having a longitudinal elongation at break of at least about 8%, optionally at least about 9%, optionally at least about 10%, optionally at least about 11%, optionally at least about 12%, optionally at least about 13%, optionally at least about 14%; and / or the longitudinal tensile strength of the cellulose layer (which may be referred to as paper or base paper) may be at least about 10 N / 15 mm.

[0035] The cellulose layer may be referred to as paper or base paper, and its longitudinal elongation at break may be at least about 14%; and / or the longitudinal tensile strength of the cellulose layer (which may be referred to as paper or base paper) may be at least about 10 N / 15 mm.

[0036] In the third aspect, a stretchable packaging material is provided, which includes a cellulose layer, which may be referred to as base paper; The longitudinal breaking elongation of the cellulose layer or base paper is at least about 14%; and The longitudinal tensile strength of the cellulose layer or base paper is at least about 10 N / 15 mm.

[0037] The basis weight of the cellulose layer or base paper can be 10 g / m². 2 Up to 150g / m 2 Optional, 20g / m 2 Up to 150g / m 2 Optional, 20g / m 2 Up to 120g / m 2 Optional, 20g / m 2 Up to 100g / m 2 Optional, 20g / m 2 Up to 80g / m 2 Optional, 20g / m 2 Up to 70g / m2 Optional, 30g / m 2 Up to 60g / m 2 Optional, 30g / m 2 Up to 60g / m 2 Weight can be measured according to ISO 536:2019-11.

[0038] The thickness of the cellulose layer or base paper can be from 0.03 mm to 0.45 mm, optionally from 0.08 mm to 0.3 mm, optionally from 0.1 mm to 0.3 mm, optionally from 0.1 mm to 0.25 mm, optionally from 0.1 mm to 0.2 mm, optionally from 0.12 mm to 0.17 mm, optionally from 0.13 mm to 0.17 mm, optionally from 0.14 mm to 0.15 mm. The thickness can be measured according to ISO 534:2012-02, for example, under a pressure of 10 kPa.

[0039] The longitudinal tensile strength of the cellulose layer or base paper is at least about 10 N / 15 mm, optionally at least 15 N / 15 mm, optionally at least 20 N / 15 mm, optionally at least 25 N / 15 mm, optionally at least 27 N / 15 mm, optionally at least 30 N / 15 mm. The longitudinal tensile strength can be measured according to ISO 1924-2:2009-05.

[0040] The transverse tensile strength of the cellulose layer or base paper is at least about 5 N / 15 mm, optionally at least 7.5 N / 15 mm, optionally at least 10 N / 15 mm, optionally at least 12.5 N / 15 mm, optionally at least 15 N / 15 mm. The transverse tensile strength can be measured according to ISO 1924-2:2009-05.

[0041] The longitudinal elongation at break of the cellulose layer or base paper may be at least about 14%, optionally at least about 15%, optionally at least about 16%, optionally at least about 17%, optionally at least about 18%. The longitudinal elongation at break may be measured in accordance with ISO 1924-2:2009-05.

[0042] The transverse elongation at break of the cellulose layer or base paper may be at least about 3%, optionally at least about 4%, optionally at least about 5%, optionally at least about 6%, optionally at least about 7%. The transverse elongation at break may be measured according to ISO 1924-2:2009-05.

[0043] The Gurley smoothness of the cellulose layer or base paper can be from 5 s 200 ml to 50 s 200 ml, optionally from 10 s 200 ml to 30 s 200 ml, optionally from 15 s 200 ml to 25 s 200 ml. Gurley smoothness can be measured according to known standard methods (e.g., ASTM), such as ASTM D202-77.

[0044] In the fourth aspect, methods for packaging objects are provided, including: The object is wrapped with stretchable packaging material according to the second or third aspect. During the wrapping process, the object can be on an industrial pallet, and the object can be spirally wrapped. If wrapping equipment is used, the equipment can be a wrapping machine for wrapping objects. An industrial pallet can be defined as a pallet used for transporting industrial goods. The width and length dimensions of the pallet can be from 50cm to 150cm, and the height is less than the width and length, for example, from 5cm to 20cm. Some pallets are standardized in size; for example, the "British" pallet is 120cm long, 120cm wide, and 14.4cm high; the "European" pallet is 120cm long, 80cm wide, and 14.5cm high; and the "Finpal" pallet is 120cm long, 100cm wide, and 14.4cm high.

[0045] Stretchable packaging material (i.e., crepe paper as described herein) can be used in roll form for industrial pallet wrapping machines. The length of the roll of stretchable packaging material (i.e., crepe paper as described herein) along its axis can be from 10 to 200 cm, optionally from 30 to 150 cm, optionally from 30 to 100 cm, optionally from 30 to 70 cm, optionally about 50 cm.

[0046] In the fifth aspect, equipment for packaging objects is provided, including: A device for wrapping a load with stretchable packaging material, the device including a packaging material support; and A stretchable packaging material is mounted on a packaging material holder, wherein the stretchable packaging material is the material according to a second or third aspect. The device can be a machine for winding around an object on a pallet. The device can be computer-controlled. The device can have a turntable and a conveying device on which the pallet can be placed, the turntable rotating as the stretchable packaging material is wound around the object; the conveying device dispensing the stretchable packaging material as the object is wound, for example, dispensing the stretchable packaging material from a reel of stretchable packaging material, and the conveying device can move vertically (up or down) during winding to achieve helical winding of the object. In an alternative embodiment, the device or a component of the device (e.g., the conveying device) can rotate around the object to wind the stretchable packaging material around the object. The device can include a stretching device for stretching the stretchable packaging material on the object. Alternatively, winding the stretchable packaging material around the object itself can cause the stretchable packaging material to stretch. The device can be a handheld device. The stretchable packaging material can be on a reel on the device.

[0047] The following is for reference Figure 1 Describe the uses of the stretchable packaging material described in this article. Figure 1The diagram shows a turntable 1 with an object 2 on a tray (not shown at the bottom of the object, as it is covered by stretchable packaging material 3). As the turntable rotates counterclockwise, the stretchable packaging material 3 is wound around the object 2. The stretchable packaging material 3 is in the form of crepe paper, prepared according to the method described herein and possessing the properties described herein. The crepe paper is supplied by a crepe paper roll 4, which is mounted on a roller 5. The roller is driven by a motor and remotely controlled to match the supply speed with the rotational speed of the object 2 on the turntable 1, which is also remotely controlled. The crepe paper is supplied by the roll 4, optionally passing through a stretching device 6, which may optionally be present and in the form of multiple vertical rollers with different tangential speeds, allowing the crepe paper to be stretched to an appropriate degree between these rollers. Alternatively, in the absence of a stretching device, simply winding the crepe paper around the object 1 achieves stretching itself. Crepe paper is supplied from stretching device 6 (or in other cases from reel 4) to conveying device 16, which is a vertically movable roller used to apply the crepe paper to the object 1 at the appropriate height. The crepe paper 3 is typically wound spirally around the object 1, so the conveying device moves vertically during winding (upward if winding begins from the bottom of the object 1, or downward if winding begins from the top of the object 1). If necessary, adhesive 3 can be applied to the crepe paper using a gluing device 8, which can move on a guide rod 9. Adhesive 3 allows the crepe paper to adhere to itself during winding of the object 1. However, crepe paper typically adheres to itself without adhesive due to interlayer friction and the stretching properties of the crepe paper—the adhesive is merely an additional means of securing the paper to itself. In practice, the process of applying crepe paper to the object 1 can be automated and computer-controlled.

[0048] In alternative implementations, crepe paper can be applied to an object manually, such as by simply wrapping a sheet of crepe paper around the object by hand; or using a device that can dispense crepe paper from a roll. The handheld device may include means for receiving the roll of crepe paper, such as a shaft / roller that can hold the roll, and any other means that facilitate the manual application of paper to the object, such as a handle for holding the device and / or a cutting device for cutting the paper after dispensing.

[0049] This document refers to various standard (e.g., ASTM or ISO) measurement methods. Unless otherwise specified, the latest version of the standard measurement method should be used, i.e., the latest version as of the date of this application.

[0050] When referring to “base paper” in this article, “base paper” may also be called “crepe paper”, “cellulose layer” or “stretched paper”.

[0051] Waterproof stretchable packaging material Current stretchable packaging materials (such as plastic films) can be waterproof (also known as water-resistant). Waterproof stretchable packaging materials are advantageous because they maintain structural integrity even under wet conditions, especially when used for wrapping transport pallets. The inventors of this application have developed a paper-based stretchable packaging material that is waterproof. Importantly, in addition to waterproofing, in some embodiments, this material also maintains or improves other properties required for stretchable packaging materials, such as elongation and tensile strength (compared to non-waterproof stretchable packaging materials). The aforementioned properties and manufacturing methods of stretch paper can also be applied to this waterproof stretchable packaging material.

[0052] The inventors have discovered that treating a cellulose layer with a hydrophobic substance yields a highly waterproof, stretchable material. Treating the cellulose layer with a hydrophobic substance means that the cellulose layer contains the hydrophobic substance. The hydrophobic substance can come into contact with the fibers of the cellulose layer at any point in time before, during, or after the formation of the cellulose layer. For example, the hydrophobic substance can come into contact with the fibers of the cellulose layer at the following points in time: before the formation of the cellulose layer (e.g., when they are in pulp), or in the paper machine after the formation of the cellulose layer while the cellulose layer is still wet and before the creping process, or at any other point in time before or after the creping process, or at any point in time after the creping process and before or after the paper is dry. Treating the cellulose layer with a hydrophobic substance can include coating or impregnating the cellulose layer before or after the wet creping process. Preferably, treating the cellulose layer with a hydrophobic substance includes impregnating the cellulose layer with the hydrophobic substance after the wet creping process; preferably, the cellulose layer has dried before impregnating the cellulose layer with the hydrophobic substance. "Impregnated" cellulose layer refers to a hydrophobic substance distributed, preferably uniformly distributed, throughout the depth of the cellulose layer. The difference between impregnation and coating is that coating a cellulose layer usually results in the substance being primarily present on the coated side, rather than being uniformly distributed throughout the depth of the cellulose layer.

[0053] Hydrophobic substances can also impart good slip and abrasion resistance to waterproof, stretchable packaging materials. The cellulose layer can be treated with a hydrophobic substance in the post-processing section of a paper machine, such as in a sizing machine. The sizing machine can be in-line (i.e., part of the papermaking equipment used to form the cellulose layer and perform creping) or offline (i.e., separate from the papermaking equipment so that the paper can be wound into a roll after creping and drying, and then later fed from that roll into an offline sizing machine to apply the hydrophobic substance). The hydrophobic substance can be applied to one side or both opposite sides of the paper, for example, in a sizing machine, where opposite sides can be defined as the surfaces of the paper that are on the same plane as the conveyor belt of the paper machine. The hydrophobic substance can be applied by impregnating the cellulose layer with the hydrophobic substance (e.g., using a sizing machine). Impregnation can be achieved by applying a hydrophobic substance in liquid form to the cellulose layer (e.g., a liquid aqueous emulsion of the hydrophobic substance), preferably while the cellulose layer is drying (and after the wrinkling process); the liquid can be a liquid emulsion or suspension of the hydrophobic substance—preferably an aqueous liquid emulsion of the hydrophobic substance.

[0054] Hydrophobic substances that can be impregnated into the cellulose layer as described above may include waxes. Waxes may be selected from plant waxes, animal waxes, and petroleum-derived waxes. Hydrophobic substances may include a variety of waxes (mixtures of waxes). Hydrophobic substances may include plant-based waxes and animal-based waxes. Compared to petroleum-based compounds (such as paraffin) used to treat paper, animal waxes and plant waxes are generally biodegradable and offer improved sustainability. Treating paper with animal-based or plant-based waxes can improve recyclability.

[0055] The hydrophobic substance that can be impregnated into the cellulose layer as described above may include one or more waxes, wherein the waxes are selected from paraffin wax, insect wax, cetacean wax, lanolin, beeswax, paraffin wax, soybean wax, candelilla wax, carnauba wax (palm wax), Chinese wax, shellac wax, myrica wax, castor wax, sage wax, pea wax, rice bran wax, sugar bran wax, crested carnauba wax, and sunflower seed wax. The hydrophobic substance may include plant-based waxes, selected from, but not limited to, lanolin, soybean wax, candelilla wax, carnauba wax, myrica wax, castor wax, sage wax, pea wax, rice bran wax, sugar bran wax, sunflower seed wax, and crested carnauba wax. The hydrophobic substance may include modified waxes or unmodified waxes. The waxes are preferably plant-based waxes. The hydrophobic substance may contain waxes containing glycerides, wherein the glycerides are selected from fatty acid triglycerides, fatty acid diglycerides, and fatty acid monoglycerides, wherein the unsaturated fatty acids in the glycerides are hydrogenated to saturated fatty acids. The hydrophobic substance preferably comprises a plant-based wax, which is hydrogenated to convert the unsaturated fatty acids in a fatty acid glyceride (which may be a glyceride selected from fatty acid triglycerides, fatty acid diglycerides, and fatty acid monoglycerides) into saturated fatty acids. In other words, the hydrophobic substance may comprise unsaturated fatty acid glycerides (which may be a glyceride selected from fatty acid triglycerides, fatty acid diglycerides, and fatty acid monoglycerides), preferably derived from plant and / or animal waxes, and more preferably derived from soybean wax. The hydrophobic substance may also comprise glycerides selected from unsaturated fatty acid triglycerides, unsaturated fatty acid diglycerides, and unsaturated fatty acid monoglycerides.

[0056] Hydrophobic substances that can be impregnated into the cellulose layer as described above may include soybean wax. Soybean wax is a plant wax that can be made from soybean oil. Soybean wax has a triglyceride containing a high proportion of stearic acid (e.g., at least 50 wt%, optionally at least 60 wt%, optionally at least 70 wt%, optionally at least 80 wt% of the fatty acids in soybean oil are stearic acid; and optionally, at least a portion of the remaining fatty acids is palmitic acid). During the manufacture of soybean wax, hydrogenation converts unsaturated fatty acids into saturated fatty acids. Soybean wax is generally softer and has a lower melting point than paraffin wax. The melting point of soybean wax can be from about 50°C to about 80°C, optionally from 60°C to about 80°C, or from 65°C to about 75°C. It is advantageous to use hydrophobic substances containing soybean wax because it is fully renewable. At least 80 wt%, optionally at least 90 wt% of the fatty acids in soybean wax may be unsaturated. It has also been found that soybean wax has improved barrier properties and can increase the tensile strength of paper compared to other plant waxes.

[0057] The hydrophobic material that can be impregnated into the cellulose layer as described above may include a wax. The wax may be a plant wax (e.g., soybean wax) with a melting point of about 30°C to about 150°C, optionally about 30°C to about 100°C, optionally about 40°C to about 90°C, optionally about 50°C to about 80°C, optionally about 60°C to about 80°C, optionally about 65°C to about 75°C, optionally about 68°C, 69°C or 70°C.

[0058] The hydrophobic material, after being applied (e.g., impregnated) to the cellulose layer, can be cured at a surface temperature of about 50°C to about 200°C, optionally about 50°C to about 150°C, optionally about 60°C to about 150°C, optionally about 70°C to about 150°C, optionally about 70°C to about 120°C, or optionally about 80°C to about 120°C. The hydrophobic material can also be cured at a temperature above the melting point of the hydrophobic material after being applied to the cellulose layer. If the cellulose layer (which may be dry before application) is wet after the application of the hydrophobic substance, for example, if the hydrophobic substance is applied to the cellulose layer in the form of an aqueous liquid (e.g., an aqueous emulsion of the hydrophobic substance), then after the application of the hydrophobic substance, the cellulose layer can be subjected to a drying process, for example, drying it at a temperature of about 50°C to about 200°C, optionally about 50°C to about 150°C, optionally about 60°C to about 150°C, optionally about 70°C to about 150°C, optionally about 70°C to about 120°C, or optionally about 80°C to about 120°C. The temperature of the drying process can be at or above the melting point of the hydrophobic substance, for example, at least 5°C above the melting point of the hydrophobic substance (e.g., a plant wax, such as soybean wax), optionally at least about 10°C.

[0059] Hydrophobic substances (e.g., plant waxes, such as soybean wax) can be applied to a cellulose layer in the form of an aqueous emulsion (e.g., impregnated into the cellulose layer). The aqueous emulsion may contain one or more waxes. The emulsion may contain an emulsifier, wherein the emulsifier is typically a compound having both polar and nonpolar portions and is commonly used to generate an emulsion between the hydrophobic compound and water. The emulsifier may be selected from nonionic, cationic, and anionic emulsifiers, with cationic emulsifiers being preferred. It has been found that cationic emulsifiers result in significantly higher adhesion between the wax and the paper fibers compared to nonionic and anionic emulsifiers, thus exhibiting greater hydrophobicity. The cationic emulsifier may contain a hydrocarbon chain (e.g., a C5 to C25 hydrocarbon chain, such as an alkyl chain) bonded to a quaternary ammonium group. The cationic emulsifier may be selected from behenyltrimethylammonium chloride, benzalkonium chloride, benzyldimethyldodecylammonium bromide, carbetoline bromide, citaloprammonium chloride, hexadecyltrimethylammonium bromide, cetrimonium bromide, cetrimonium chloride, citaloprammonium chloride, decamethylammonium chloride, dioctadecyldimethylammonium bromide, dioctadecyldimethylammonium chloride, dioleoyl-3-trimethylammonium propane, domiphen, ethyl lauroyl arginine, lauryl methyl glucetol polyether-10-hydroxypropyl dimethylammonium chloride, oteninidine dihydrochloride, olafluridine, N-oleoyl-1,3-propanediamine, pahutoxin, silachlor, tetramethylammonium hydroxide, and tonzoammonium bromide. The amount of emulsifier present to emulsify the hydrophobic substance in the aqueous liquid can be determined by those skilled in the art. The emulsifier may be a naturally occurring substance or derived from a naturally occurring substance, for example, not made from fossil fuel resources.

[0060] In a preferred embodiment, a stretchable packaging material as described herein is provided, wherein the cellulose layer is impregnated with a hydrophobic substance after a wet creping process, preferably a plant wax as described herein.

[0061] If a hydrophobic substance (such as plant wax, like soybean wax) is impregnated into the cellulose layer, the amount of hydrophobic substance present in the cellulose layer can be approximately 1 g / m³. 2 Approximately 20g / m 2 The optional location is approximately 2g / m 2 Approximately 10g / m 2 The optional amount is approximately 3g / m 2 Approximately 10g / m 2 The optional amount is approximately 3g / m 2 Approximately 7g / m 2 The optional location is approximately 5g / m 2 .

[0062] If a hydrophobic substance is coated onto a cellulose layer, it can be applied to one side of the cellulose layer in an amount of approximately 1 g / m². 2 Approximately 20g / m2 The optional location is approximately 2g / m 2 Approximately 10g / m 2 The optional amount is approximately 3g / m 2 Approximately 10g / m 2 The optional amount is approximately 3g / m 2 Approximately 7g / m 2 The optional location is approximately 5g / m 2 .

[0063] If a hydrophobic substance is coated onto a cellulose layer, it can be applied to both sides of the cellulose layer, with an amount of approximately 1 g / m² on each side. 2 Approximately 20g / m 2 The optional location is approximately 2g / m 2 Approximately 10g / m 2 The optional amount is approximately 3g / m 2 Approximately 10g / m 2 The optional amount is approximately 3g / m 2 Approximately 7g / m 2 The optional location is approximately 5g / m 2 Hydrophobic substances can be coated on both sides of the cellulose layer at the same weight. Alternatively, hydrophobic substances can be coated on opposite sides of the cellulose layer at different amounts.

[0064] Waterproof stretchable packaging material can have a weight of 10g / m³. 2 Up to 150g / m 2 Optional, 20g / m 2 Up to 150g / m 2 Optional, 20g / m 2 Up to 120g / m 2 Optional, 20g / m 2 Up to 100g / m 2 Optional, 20g / m 2 Up to 80g / m 2 Optional, 20g / m 2 Up to 70g / m 2 Optional, 30g / m 2 Up to 60g / m 2 Optional, 30g / m 2 Up to 60g / m 2 Weight can be measured according to ISO 536:2019-11 or ISO 9073-1:2023.

[0065] After treating the stretchable packaging material with a hydrophobic substance, the hydrophobic substance may account for about 1% to about 20% of the weight of the waterproof stretchable packaging material, optionally about 2% to about 15%, optionally about 5% to about 12%, optionally about 5% to about 10%, optionally about 8%.

[0066] The Cobb 60 value is a measure (in g / m²) of the amount of water absorbed by a defined area of ​​cellulose layer within 60 seconds of single-sided contact with water. 2) It can be used to evaluate the water resistance or water-resistance of cellulose layers. In this invention, the Cobb 60 value is measured according to DIN ENISO 535 2014-06. The Cobb 60 value of waterproof stretchable packaging materials can be less than 50 g / m³. 2 Optional, less than 40g / m 2 Optional, less than 30g / m 2 Optional, less than 20g / m 2 The optional location is approximately 15g / m 2 The Cobb 60 value of waterproof, stretchable packaging materials can be approximately 1 g / m³. 2 Approximately 50g / m 2 The optional location is approximately 2g / m 2 Approximately 40g / m 2 The optional location is approximately 5g / m 2 Approximately 30g / m 2 The optional location is approximately 10g / m 2 Approximately 20g / m 2 .

[0067] The longitudinal tensile strength of the waterproof, stretchable packaging material is at least about 10 N / 15 mm, optionally at least 15 N / 15 mm, optionally at least 20 N / 15 mm, and optionally at least 25 N / 15 mm. The longitudinal tensile strength can be measured according to ISO 1924-2:2009-05.

[0068] The transverse tensile strength of the waterproof stretchable packaging material may be at least about 10 N / 15 mm, optionally at least 5 N / 15 mm, optionally at least 7.5 N / 15 mm, optionally at least 10 N / 15 mm, optionally at least 14 N / 15 mm. The longitudinal tensile strength may be measured according to ISO 1924-2:2009-05.

[0069] The longitudinal elongation at break of the waterproof, stretchable packaging material may be at least 7.5%, optionally at least 8%, optionally at least 9%, optionally at least 10%. The longitudinal elongation at break may be measured in accordance with ISO 1924-2:2009-05.

[0070] The transverse elongation at break of the waterproof, stretchable packaging material may be at least 5%, optionally at least 6%, optionally at least 7%, optionally at least 8%. The longitudinal elongation at break may be measured according to ISO 1924-2:2009-05.

[0071] Waterproof stretchable packaging materials can have a breathability of at least 10 l / m 2 / s, optionally at least 12 l / m 2 / s, optionally at least 14 l / m 2 / s, optionally at least 16 l / m 2 / s. Air permeability can be measured according to ISO 9237 1995-12.

[0072] The burst strength of the waterproof, stretchable packaging material may be at least 120 kPa, optionally at least 140 kPa, optionally at least 160 kPa, optionally at least 170 kPa, optionally at least 180 kPa. The burst strength may be measured according to DIN ENISO 535 2014-06.

[0073] Waterproof stretchable packaging materials can be produced in the same manner and using the same equipment as those described above for stretchable packaging materials and cellulose layers.

[0074] Example Example 1 Manufacturing stretched paper using a wet creping process In papermaking equipment, a mixture of two types of NBSK cork (70 wt% Canadian NBSK and 30 wt% Scandinavian NBSK) and water is used to prepare pulp (or stock) in a pulper. (Both types of NBSK are supplied in sheet form and bundled before use.) The pulp is then stored in a stock until needed; at this point, the pulp consistency (solids content) is 4 wt%. The pulp is then refined to a refinement of at least 85° as measured using the Schopper-Riegler test. The refined pulp is then further diluted with water to a consistency of 0.5–1 wt% and pumped via headbox to the wire section of a two-wire paper machine. The pulp is then passed through the press section of the machine, through three press rolls, and creased at the creasing roller (the upper roll of the third press roll). When creased with a doctor blade, the dry content of the pulp is approximately 35 wt% (i.e., approximately 65 wt% water), which is a wet creasing process.

[0075] After the doctor blade, the paper is fed through a rotating felt and passes through the drying section. In the drying section of the machine, the paper is dried by steam-heated drying drums (sometimes called drying cylinders) and then wound into a roll at the end of the machine.

[0076] The paper is then loaded into a post-processing unit, where it is unrolled and treated as needed, such as by applying a surface sizing agent (which may contain hydrophobic polymers and / or suitable minerals, such as alkyl ketone dimers, latex, and / or kaolin) to one or both sides of the paper to provide moisture / water resistance. It is then rewound into a roll for storage. The paper can be cut to specific widths as needed before or during post-processing.

[0077] Various properties of the stretched paper were measured, and the results are shown in Table 1 below.

[0078] Table 1 Of particular note is that the paper of this invention exhibits a higher longitudinal elongation, reaching 18%, compared to other papers. Nevertheless, its longitudinal tensile strength is also relatively high, reaching 30 N / 15 mm. Prior to this invention, it was difficult to simultaneously achieve high elongation and high tensile strength. Furthermore, the paper possesses a suitable surface roughness to provide a surface with reasonably high friction, which is very useful when used as packaging paper.

[0079] Example 2 The use of paper in industrial stretch wrapping machines In an industrial stretch wrapping machine typically used for stretch wrapping polymer films, the stretch wrapping paper prepared in Example 1 is loaded in roll form, replacing a typical polymer film roll. The equipment operates under substantially the same conditions as that used for polymer films to wrap cuboid objects on a pallet, except that the stretch degree may be slightly lower. The paper is successfully wrapped around the object on the pallet in the same manner as with polymer films, stretched, and adhered to the object (by means of the frictional tension between the paper layers). This demonstrates that stretch wrapping paper can be used instead of polymer films with minimal adjustments to the stretch wrapping machine. Using paper as the stretch wrapping material means that the use of polymer shrink wrapping materials can be avoided, which can be advantageous from an environmental perspective. The stretch wrapping paper can be recycled after use for wrapping objects.

[0080] Besides industrial uses, such as wrapping objects on pallets, stretch paper can be used for any object that needs to be wrapped. For example, it can be used as a label on a container, printed before or after wrapping as needed, or used to hold one or more objects together. It can be used to wrap objects in any environment, including a home environment, and requires no machine operation—it can also be done manually.

[0081] Example 3 Waterproof stretch paper The inventors discovered that highly waterproof stretch paper can be produced by impregnating base paper with a cationic plant-based wax (i.e., an emulsion of plant-based wax and a cationic emulsifier), particularly a water-based cationic emulsion of soybean wax. The water resistance of the stretch paper allows it to maintain its structural integrity during use. The impregnation with soybean wax creates a lotus leaf effect on the material surface, thus giving the stretch paper its superior water resistance.

[0082] Stretched paper was prepared according to the method described in Example 1, but in the post-processing section of the equipment, i.e., after the paper creping process and drying, a plant wax in emulsion form was applied in the sizing machine of the paper machine. This impregnates the paper with the plant wax. After impregnation, the paper was dried at a temperature of 80°C to 110°C. In addition to drying, this temperature also serves to solidify the wax—the wax melts near the fibers and coats them to achieve maximum hydrophobicity and protect the fibers. The cationic emulsifier also promotes the adhesion of the wax to the anionic surface of the fibers.

[0083] The properties of the waterproof stretch paper were measured, and the results are listed in Table 2 below. Comparative tests on non-hydrophobic impregnated stretch paper are also provided. For each property, four samples of both unimpregnated and waterproof stretch paper were analyzed. The average values ​​of the four samples are given in the table.

[0084] Table 2 Stretch paper impregnated with soybean wax exhibits better water resistance than unimpregnated stretch paper without hydrophobic substances. This can be seen from the Cobb 60 value (which provides information about the sample's absorbency), where it compares to 76 g / m³ for unimpregnated stretch paper. 2 In comparison, impregnated stretch paper has a much lower Cobb 60 value of 17 g / m². 2 The Cobb test measures the amount of water absorbed by a paperboard or paper of a defined area through single-sided contact with water within a certain time period. Cobb 60 refers to the amount of water absorbed by the paper after 60 seconds of contact with water.

[0085] Impregnated stretch paper achieves improved water resistance while retaining other desirable properties. Another advantage achieved through impregnation is increased longitudinal tensile strength (37.88 N / 15 mm, compared to 36.58 N / 15 mm). This unexpected increase in tensile strength, combined with improved water resistance, makes this stretch wrapping paper more suitable as a wrapping material.

[0086] Another type of waterproof stretch paper was prepared using the above method, and its property measurement results are shown in Table 3 below. As shown above, 45 g / m... 2 The base paper is processed using a method similar to that described above with 5 g / m 2 The mixture was impregnated with cationic soybean wax.

[0087] Table 3 This disclosure also includes the following numbered statements.

[0088] 1. A method for manufacturing a stretchable packaging material, the method comprising: A cellulose layer is made from refined wood pulp, wherein the refined wood pulp has been refined to a degree of at least about 70°SR; and The cellulose layer is subjected to a wet wrinkling process.

[0089] 2. The method according to Statement 1, wherein the refined wood pulp has been refined to a refinement of at least about 75°SR, optionally at least about 80°SR.

[0090] 3. The method according to Statement 1 or Statement 2, wherein the refined wood pulp comprises at least 80 wt% softwood, optionally at least 90 wt% softwood.

[0091] 4. The method according to Statement 3, wherein the cork includes Canadian NBSK and Scandinavian NBSK.

[0092] 5. The method according to statement 4, wherein the Canadian NBSK and Scandinavian NBSK are present in a weight ratio of 1:4 to 4:1, optionally 4:1 to 1:1.

[0093] 6. The method according to any one of the foregoing statements, wherein the dry content of the paper before creping is 70 wt% or less, optionally 50 wt% or less, optionally 40 wt% or less.

[0094] 7. The method according to any one of the foregoing statements, wherein after the wet creping process, an adhesive or hydrophobic substance is coated on at least one side of the paper.

[0095] 8. A stretchable packaging material comprising a base paper; The longitudinal breaking elongation of the base paper is at least about 14%; and The longitudinal tensile strength of the base paper is at least about 10 N / 15 mm.

[0096] 9. A stretchable packaging material comprising a base paper, wherein the base paper is or comprises a cellulose layer capable of being manufactured according to any one of statements 1 to 7, optionally wherein the base paper is as defined in statement 8.

[0097] 10. The stretchable packaging material according to statement 8 or 9, wherein the basis weight of the base paper is 30 to 80 g / m². 2 .

[0098] 11. The stretchable packaging material according to any one of claims 8 to 10, wherein the base paper is formed from a pulp comprising Canadian NBSK and Scandinavian NBSK, and optionally, Canadian NBSK and Scandinavian NBSK are present in the base paper in a weight ratio of 1:4 to 4:1, optionally 4:1 to 1:1.

[0099] 12. A method for packaging an object, comprising: The object is wrapped with the stretchable packaging material according to any one of statements 8 to 11.

[0100] 13. An apparatus for packaging objects, comprising: A device for wrapping a load with a stretchable packaging material, the device comprising a packaging material support; and A stretchable packaging material mounted on the packaging material support, wherein the stretchable packaging material is the material described in statements 8 to 11.

[0101] 14. The method according to statement 12, wherein during winding, the object is located on an industrial pallet and the object is spirally wound using the equipment according to statement 13.

[0102] 15. The method according to statement 14, wherein the device is a winding machine for winding and stretching an object wound on the industrial pallet.

Claims

1. A method for manufacturing a stretchable packaging material, the method comprising: A cellulose layer is made from refined wood pulp, wherein the refined wood pulp has been refined to a refinement of at least about 70°SR; as well as The cellulose layer is subjected to a wet wrinkling process.

2. The method of claim 1, wherein the refined wood pulp has been refined to a refinement of at least about 75°SR, optionally at least about 80°SR.

3. The method according to claim 1 or 2, wherein the refined wood pulp comprises at least 80 wt% softwood, optionally at least 90 wt% softwood.

4. The method of claim 3, wherein the cork comprises Canadian NBSK and Scandinavian NBSK.

5. The method of claim 4, wherein the Canadian NBSK and Scandinavian NBSK are present in a weight ratio of 1:4 to 4:1, optionally 4:1 to 1:

1.

6. The method according to any one of the preceding claims, wherein the cellulose layer has a dry content of 70 wt% or less before wrinkling, optionally 50 wt% or less, optionally 40 wt% or less.

7. The method according to any one of the preceding claims, wherein the cellulose layer is treated with an adhesive or a hydrophobic substance after the wet wrinkling process.

8. The method of claim 8, wherein the hydrophobic substance comprises plant wax, optionally including soybean wax, containing a glyceride selected from unsaturated fatty acid triglycerides, unsaturated fatty acid diglycerides and unsaturated fatty acid monoglycerides.

9. The method according to claim 7 or 8, wherein after the wet wrinkling process, the hydrophobic material is impregnated into the cellulose layer in the form of a cationic emulsion.

10. A stretchable packaging material that can be manufactured by the method according to any one of claims 1 to 9.

11. The stretchable packaging material of claim 10, wherein the longitudinal elongation at break of the stretchable packaging material is at least about 8%, optionally at least about 10%, optionally at least about 14%; and The longitudinal tensile strength of the cellulose layer is at least about 10 N / 15 mm.

12. The stretchable packaging material according to claim 11, wherein the basis weight of the stretchable packaging material is 30 to 80 g / m³. 2 .

13. The stretchable packaging material according to any one of claims 10 to 12, wherein the cellulose layer of the stretchable packaging material has been formed from a pulp comprising Canadian NBSK and Scandinavian NBSK, and optionally, the Canadian NBSK and Scandinavian NBSK are present in the cellulose layer in a weight ratio of 1:4 to 4:1, optionally 4:1 to 1:

1.

14. The stretchable packaging material according to any one of claims 10 to 13, wherein the cellulose layer has been treated with the following substances before or after the wet creping process: (i) a plant wax, optionally soybean wax, comprising glycerides selected from unsaturated fatty acid triglycerides, unsaturated fatty acid diglycerides and unsaturated fatty acid monoglycerides; and (ii) optionally a cationic emulsifier.

15. A method for packaging an object, comprising: The object is wrapped with the stretchable packaging material according to any one of claims 10 to 14.

16. An apparatus for packaging objects, comprising: An apparatus for wrapping a load with a stretchable packaging material, the apparatus including a packaging material support; as well as A stretchable packaging material mounted on the packaging material support, wherein the stretchable packaging material is the material according to claims 10 to 15.

17. The method of claim 15, wherein during winding, the object is located on an industrial pallet, and the object is helically wound using the apparatus of claim 16.

18. The method of claim 17, wherein the device is a winding machine for stretching one or more objects wound on the industrial pallet.

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