bendable solid cellulose foam

Abstract

1. A foldable, solid cellulose foam, the foldable, solid cellulose foam having an upper surface and a lower surface, at least one of the upper surface and the lower surface of the foldable, solid cellulose foam including at least one cut line having a predetermined cut depth DC, the at least one cut line being positioned to cut partially through the cellulose foam. The present invention also provides a method for producing the foldable, solid cellulose foam.

Description

[Technical Field]

[0001] The present invention relates to the field of cellulose foams for packaging, and more particularly to foldable solid cellulose foams.

[0002] The present invention further relates to a method for producing a bendable solid cellulose foam. [Background technology]

[0003] Plastic packaging materials, such as fossil-based foams, are becoming increasingly outdated in a society striving to reduce plastic use and waste and move toward renewable materials. With regulatory agencies now driving policies toward restricting or banning fossil-based foam materials in packaging, new solutions are needed.

[0004] There are many challenges in finding foams from renewable sources. Many bio-based foams have higher production costs, lower mechanical performance, and lower stability in water or at high temperatures compared to established foams from petroleum-based sources. Bio-based, recyclable protective materials need to have the same excellent characteristics and properties as petroleum-based protective materials to be the first choice over petroleum-based materials.

[0005] The low weight and good impact absorption of bio-based foams are examples of important features. Also, the ability to customize the shape and form of the bio-based foam to match the shape and form of the product to be protected by the protective material is of paramount importance. Cellulose has been shown to be the most abundant renewable natural polymer on Earth, with its crystalline structure and the availability of methods for its preparation in large quantities on an industrial scale.

[0006] Several bio-based foams containing cellulose have been described. WO20200011587 describes a porous material prepared by aerating a paste containing cellulose fibers and gluten and depositing the aerated paste into a dried mold. WO2015036659 describes a molded fiber product prepared by foaming an aqueous suspension of natural fibers in combination with synthetic fibers and a surfactant, feeding the fiber foam into a mold, and drying it to produce a dry fiber product.

[0007] In packaging applications, the goods to be protected often have protruding parts, such as corners and edges, or complex three-dimensional (3D) shapes that require additional protection from the packaging material during storage and transportation. Furthermore, goods may be made of sensitive materials, such as glass or porcelain, that require protection due to their fragile nature. Solid cellulose foams can be an interesting alternative in such applications. However, commercially available solid cellulose foams often cannot provide the necessary protection for protruding parts, such as corners and edges, or complex 3D shapes due to the rigidity, flexibility, and stiffness of bio-based foams. It is often impossible to bend or fold the solid foam around an object without the bio-based foam cracking and breaking.

[0008] There remains a need for a solid cellulose foam that can be tailored around any shaped item and protect all parts of the item. The item needs to be well protected so that shocks occurring during storage and transportation are absorbed by the surrounding cellulose foam, thereby preventing the shocks from damaging the item.

[0009] Additionally, solid cellulose foams should be renewable, biodegradable, and fully recyclable within the normal paper and board flow, allowing them to become part of the circular material flow in existing packaging waste management systems. The manufacturing costs, not only to produce the foam but also to tailor the foam to any product shape, must be reasonable to be a competitive option.

[0010] To conserve raw materials, there is also a need to reduce the amount of protective material used in protective packaging and minimize waste.

[0011] Additionally, a need exists for protective packaging that can be easily transported to a location where the goods are packaged within the protective packaging. The protective packaging needs to provide three-dimensionally tailored protection for the goods, but also needs to take up as little space as possible during transportation to the packaging location. Summary of the Invention

[0012] SUMMARY OF THE INVENTION It is an object of the present invention to provide a bendable solid cellulose foam that obviates at least some of the drawbacks of the prior art.

[0013] According to the solution of claim 1, a bendable solid cellulose foam is provided with an upper surface and a lower surface, at least one of the upper surface and the lower surface of the bendable solid cellulose foam includes at least one cutting line of a predetermined cutting depth DC, the at least one cutting line being positioned to cut partially through the cellulose foam, and the bendable solid cellulose foam is provided with at least one hinge for folding the cellulose foam so that the foam can be easily folded around angular shapes such as corners or edges of the item to be protected, thereby providing cushioning to the item.

[0014] Another advantage is that the foldable solid cellulose foam is a flat material that takes up very little space when stored or transported to the point of use, yet - due to the possibility of folding the solid cellulose foam - the foam can be tailored to fit around three-dimensional objects, even those with complex shapes, and protect the object with the cushioning properties of the foam.

[0015] Another advantage is that the predetermined cut depth is smaller than the thickness of the cellulose foam and is disposed in the direction of said thickness, thereby allowing the foam to remain in one piece. No waste is produced.

[0016] A further advantage is that the cutting direction into the foam is selected depending on the shape of the product to be protected by the foam, which means that there is a great possibility to adjust the shape of the bendable foam to the shape of the product.

[0017] Another advantage is that the at least one cut line may be a straight cut line, a curved cut line, an angled cut line including at least one angle, an irregularly shaped cut line, or any combination thereof, which also means that there is a great possibility to adapt the shape of the bendable foam to the shape of the product.

[0018] Yet another advantage is that the at least one cut line can be arranged to include at least one section having a predetermined cut depth less than the thickness of the cellulose foam and at least one section having a predetermined cut depth equal to the thickness of the cellulose foam. A section having a predetermined cut depth equal to the thickness of the cellulose foam means that the cut line section cuts completely through the foam, which can provide numerous design opportunities for the foam. For example, a through cut provides a portion of the cellulose foam that can be removed, leaving a void useful for a housing to enclose a product.

[0019] The method for producing the flexible solid cellulose foam is cost-effective to implement on existing manufacturing lines.

[0020] This method may lead to cheaper and easier manufacturing and improved product quality.

[0021] The method is also easy to implement in large scale setups.

[0022] Further aspects and embodiments are defined in the appended claims, which are specifically incorporated herein by reference.

[0023] The foregoing aspects and many of the attendant advantages of this invention will become more readily appreciated as the same becomes better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings, in which: The invention will now be explained in more detail with reference to the accompanying drawings. [Brief explanation of the drawings]

[0024] [Figure 1a] 1A and 1B show the solid cellulosic foam in an unfolded and folded state, respectively. [Figure 1b] 1A and 1B show the solid cellulosic foam in an unfolded and folded state, respectively. [Figure 2a] 1A-1C show different views of unfolded and folded solid cellulosic foam. [Figure 2b] 1A-1C show different views of unfolded and folded solid cellulosic foam. [Figure 2c] 1A-1C show different views of unfolded and folded solid cellulosic foam. DETAILED DESCRIPTION OF THE INVENTION

[0025] Before the present invention is disclosed and described in detail, it is to be understood that the invention is not limited to the particular compounds, compositions, method steps, substrates, and materials disclosed herein, as such compounds, compositions, method steps, substrates, and materials may vary somewhat. It is also to be understood that the terminology used herein is used for the purpose of describing particular embodiments only, and is not intended to be limiting, since the scope of the present invention will be limited only by the appended claims and equivalents thereof.

[0026] It should be noted that as used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise.

[0027] Unless otherwise defined, all terms and scientific terms used herein are intended to have the meaning commonly understood by one of ordinary skill in the art to which this invention belongs.

[0028] As used herein, a "plank" refers to an object that is flat and has an upper and lower surface. In most cases, the surfaces are parallel, meaning that the plank has a uniform, or at least substantially uniform, thickness.

[0029] As used herein, "flexible" means bendable, stretchable, twistable, bendable and / or foldable.

[0030] As used herein, "flexible material" refers to a material that can bend, stretch, twist, bend, and / or fold. The difference between folding and bending is that folding results in sharp angles at narrow hinges, while bending is a global deformation that results in a smoother curvature. A fold can be interpreted as a well-defined, precise bend that occurs about a folding axis.

[0031] As used herein, "rigid" means inflexible. A material that is rigid cannot be bent, stretched, twisted, bent, and / or folded without cracking and / or breaking.

[0032] As used herein, "predetermined cutting depth" means that the cutting depth is predetermined prior to making or performing said cut.

[0033] As used herein, the term "foam" refers to a material created by entrapping air or gas bubbles within a solid or liquid. Generally, the volume of gas is much greater than the volume of the liquid or solid, and a thin film separates the pores. To form a foam, three requirements must be met: Mechanical work is required to increase the surface area. This can occur by agitation, dispersion of a large amount of gas into the liquid, or injection of gas into the liquid. The second requirement is the presence of a blowing agent, typically an amphiphile, surfactant, or surface-active component, to reduce surface tension. Finally, the foam must form more quickly than it can break down.

[0034] The term "cellulose foam" as used herein refers to a foam containing cellulose and other components such as thickeners, surfactants, and additives. The main component of cellulose foam is cellulose, which constitutes at least 70% by weight of the dry content of the cellulose foam. The cellulose is in the form of fibers, and therefore the foam can also be defined as a fiber foam or a cellulose fiber foam. The cellulose foam can be wet or solid.

[0035] As used herein, the term "wet foam" or "wet cellulose foam" refers to a wet foam containing cellulose and other components such as thickeners, surfactants, and additives. Air bubbles are present in the wet foam. The wet foam is self-supporting and behaves as a viscoelastic solid, meaning that the wet foam has both viscous and elastic properties. The wet foam behaves as a solid and is therefore self-supporting unless a sufficiently large force is applied that it begins to flow and instead behaves as a viscous material. Depending on the magnitude and time scale of any applied shear stress, the wet foam can exhibit predominantly viscous or elastic behavior.

[0036] As used herein, the terms "solid cellulose foam" or "dried cellulose foam" refer to a dry porous cellulose material formed from wet cellulose foam, i.e., a foam-molding material. During the drying process, the closed wet cellulose foam is converted into an open solid cellulose foam. The cellulose fiber network is prevented from collapsing during drying. The resulting solid cellulose foam has a shape that largely conforms to the shape of the wet cellulose foam. The dry content of the solid cellulose foam can be at least 95% by weight, calculated based on the total weight of the solid cellulose foam. The shape and density of the solid cellulose foam are retained even in an unconstrained state. The solid cellulose foam has an open-cell structure, allowing air to enter the pores within the foam. The solid cellulose foam can also be described as a porous or low-density material.

[0037] The following detailed description and the examples included therein are provided only for the purpose of describing and illustrating certain embodiments of the invention, and are not intended to limit the scope of the invention in any way.

[0038] In a first aspect, the present invention relates to a bendable solid cellulose foam.

[0039] In a second aspect, the present invention provides a method for producing the bendable solid cellulose foam.

[0040] The solid cellulose foam preferably comprises: a) 71 to 95% by weight of cellulose fibers, calculated based on the total weight of the solid content of the composition; b) 4 to 24% by weight of a water-soluble thickener, calculated based on the total weight of the solid content of the composition; c) at least two surfactants; The cellulose foam may be prepared from a cellulose foam composition comprising:

[0041] Cellulose fibers suitable for use in the present invention can be derived from wood, such as softwood or hardwood, leaves, or fiber crops (including cotton, flax, and hemp). Cellulose fibers suitable for use in the present invention can also be derived from regenerated cellulose, such as rayon and lyocell. Cellulose fibers suitable for use in the present invention may contain lignin or hemicellulose, or both, or the cellulose fibers may be free of lignin and hemicellulose. Preferably, the cellulose fibers are derived from wood, and more preferably, they are pulp fibers obtained by a pulping process that liberates fibers from the wood matrix. They can be liberated by mechanical pulping, such as thermomechanical pulping (TMP) or chemothermomechanical pulping (CTMP), or by chemical pulping, such as kraft pulp or pulps obtained by sulfite, soda, or organosolv pulping processes. More preferably, the cellulose fibers are pulp fibers liberated by chemical pulping. The different characteristics of each cellulose fiber affect the properties of the final cellulose foam. Cellulose fibers are significantly longer than they are wide. Cellulose fibers can have an average width of 0.01 to 0.05 mm. Softwood fiber lengths can be 2.5 to 4.5 mm, while hardwoods can have fiber lengths of 0.7 to 1.6 mm, and eucalyptus can have fiber lengths of 0.7 to 1.5 mm. However, fiber lengths can vary considerably depending on the growing location. Cellulose fibers in the cellulose foams disclosed herein can have lengths of 0.1 mm to 65 mm, or 0.1 mm to 10 mm, or 0.5 mm to 65 mm, or 0.5 mm to 10 mm, or 0.5 mm to 7 mm. Fiber length can impart various mechanical characteristics to the foam. Due to the fiber length, the fibers can intertwine with each other, providing fiber-to-fiber interconnections that provide strength to the foam. The aspect ratio of the cellulose fibers in the cellulose foam according to the present invention, i.e., the ratio of fiber length to fiber width, can be at least 10, at least 25, at least 50, at least 75, or at least 100, which helps maintain and stabilize the foam structure during the drying process and allows the wet cellulose foam to dry while retaining its shape.The aspect ratio can be up to 6500, or preferably up to 2000.

[0042] The cellulose fibers may be modified to impart different properties to the final cellulose foam, for example, phosphated or periodate oxidized fibers may also be used when producing cellulose foams according to the present invention.

[0043] The cellulose fibers of the cellulose foam composition may be selected from wood pulp, regenerated cellulose fibers, and vegetable fibers such as fibers from bamboo, cotton, hemp, flax, and jute.

[0044] Preferably, the cellulose fibers are selected from wood pulp, such as softwood pulp, hardwood pulp, chemical thermomechanical pulp and dissolving pulp, or a combination of one or more of these.

[0045] More preferably, the cellulose pulp fibers are selected from softwood pulp, chemical thermomechanical pulp, or dissolving pulp.

[0046] Most preferably, the cellulose pulp fibers are selected from softwood pulps, such as softwood kraft bleached pulp.

[0047] The water-soluble thickener may be present in an amount of 4 to 24 wt. %, or 5 to 20 wt. %, calculated based on the total weight of the solids content of the foam. The thickener may have a molecular weight of 80,000 to 250,000 g / mol or 83,000 to 197,000 g / mol. Exemplary water-soluble thickeners are selected from carboxymethyl cellulose (CMC), methyl cellulose (MC), hydroxyethyl cellulose (HEC), ethyl hydroxyethyl cellulose (EHEC), methyl hydroxypropyl cellulose (MHPC), starch, xanthan, guar gum, and xyloglucan, or mixtures thereof.

[0048] The foam preferably comprises a mixture of at least two surfactants. One of the at least two surfactants is preferably a fast-acting surfactant, which quickly settles to the air-water interface during mechanical agitation during foam preparation, which helps to form a foam with high density and viscosity, thus enabling a self-supporting foam. A surfactant suitable for this purpose is an anionic surfactant, preferably a low-molecular-weight anionic surfactant. The low-molecular-weight anionic surfactant may be selected from sodium dodecyl sulfate (SDS), potassium dodecyl sulfate, sodium laureth sulfate (SLES), sodium dodecylbenzenesulfonate, sodium cocoyl sarcosinate, and sodium lauroyl sarcosinate. The low-molecular-weight anionic surfactant is preferably selected from sodium dodecyl sulfate (SDS), sodium pn-dodecylbenzenesulfonate, sodium cocoyl sarcosinate, and sodium lauroyl sarcosinate. More preferably, the low-molecular-weight anionic surfactant is sodium cocoyl sarcosinate. The anionic surfactant may be biodegradable.

[0049] The other of at least two surfactants is preferably a co-surfactant.Co-surfactant may be selected from plant-derived raw materials, such as tetradecanoic acid (myristic acid), sodium oleate, lauric acid, palmitic acid and stearic acid, glucose-based co-surfactants with aliphatic carbon tails, such as alkylglycosides, alkylpolyglucosides, alkylthioglycosides and alkylmaltosides, amphoteric betaines, such as cocamidopropyl betaine (CAPB), sodium cocoiminodipropionate (CADP), polyethylene glycol sorbitan monolaurate, i.e., tween (for example, tween 20, tween 80 and tween 85), and high pKa fatty acids, such as polyoxyethylene lauryl ether, for example, polyethylene glycol dodecyl ether, pentaethylene glycol monododecyl ether and octaethylene glycol monododecyl ether.

[0050] The foam composition preferably comprises: a) disintegrating cellulose fibers in water to obtain a slurry of cellulose fibers; b) adding a thickener to the slurry obtained in a) to obtain a mixture of thickener and cellulose fibers in water; c) adding at least two surfactants to the mixture obtained in b) to obtain a fiber suspension; d) aerating the suspension obtained in c) to obtain a wet foam, the wet foam comprising 10-38 wt. % of cellulose fibers, 0.5-10 wt. % of a water-soluble thickener, and 0.1-2 wt. % of a surfactant, calculated based on the total weight of the wet foam, and the wet foam has a viscosity of 140-500 kg / m 3 and a yield stress of 40 to 400 Pa; e) drying the wet foam obtained in d) to obtain a dry cellulose foam. It can be prepared by a method comprising:

[0051] The wet foam can be dried without the use of a mold, i.e., the wet foam is free-standing and retains its shape during drying without the need for a mold.

[0052] Wet foams are homogeneous and have good stability due to the small cell size (typically less than 100 μm) obtained when aerating a mixture of cellulose fibers, thickeners, and surfactants. Wet foams do not aggregate during processing. The average cell size is largely maintained during any subsequent processing or drying steps, and the cellulose fibers remain well dispersed. The solid cellulose foam obtained by drying the wet foam is uniform in structure, strong, has good mechanical properties, a smooth surface, and is defect-free. In comparison, less stable wet cellulose foams have a larger average cell size (i.e., typically greater than 100 μm), and the cells coalesce quickly during processing and drying, resulting in the formation of larger cells. Furthermore, the cellulose fibers form clusters during processing and drying, which causes the wet foam to collapse during drying. The resulting solid cellulose foam does not have a homogeneous structure and also contains defects in the morphology of the cavities caused by the coalesced cells in the wet foam. Due to these defects, such solid cellulose foams have a weak and rough surface.

[0053] The dried cellulose foam obtained in step e) can be used as a solid cellulose foam in the present invention.

[0054] The dried cellulose foam obtained in step e) depositing discrete units of cellulose foam on a surface to obtain a first foam deposit; depositing wet cellulose foam between the discrete units to obtain a subsequent foam deposit; and drying the wet foam to obtain a solid foam having the discrete units of foam embedded in a foam matrix. The solid cellulose foam may then be used as a solid cellulose foam according to claim 1 and its dependent claims.

[0055] However, the solid cellulose foam may be prepared by other methods without departing from the scope of the present invention. For example, the solid cellulose foam may be prepared by depositing a wet foam in a single step into any desired shape. Optionally, any suitable confining means, such as a mold or frame, may be used.

[0056] The solid cellulose foam material may be prepared, for example, by depositing a foam composition onto a conventional papermaking machine for forming a foam web, or onto the forming section of a papermaking machine suitably modified for that purpose.

[0057] The production of solid cellulose foam involves different manufacturing steps, one of which is the drying step. During this drying step, the outer surface (top, bottom, and sides) of the foam acquires an outer layer with different properties from the bulk part of the foam, which contains a more uniform and porous open-cell fiber network. The outer layer has a higher density than the bulk part because the fibers are more densely packed and partially oriented in a different direction. The bulk is very porous, while the densified layer has a denser structure than the core, but is still porous. The outer layer is called the "densified layer" or "densified outer layer." The densified layer improves the mechanical stability and strength of the foam.

[0058] The densified layer is a very thin layer that forms on the very outer surface of the cellulose foam during drying. The densified layer is composed primarily of cellulose fibers oriented in a two-dimensional plane (xy-plane), while the fibers in the bulk of the cellulose foam contain fiber clusters oriented in three-dimensional space with more open space between the clusters. The two-dimensional structure of the cellulose fibers in the densified layer rapidly but gradually transitions to the three-dimensional structure found in the bulk of the cellulose foam. The thin thickness of the densified layer means that it does not substantially affect the overall density of the cellulose foam.

[0059] With the densified layer having improved mechanical stability and providing strength to the foam, it may be preferable to orient the surface comprising the densified layer in a direction where additional stability may be required.

[0060] The improved properties of the densified layer are used in locations on the product where they can contribute to the protective properties of the product. Although having a higher density, the densified layer is still very porous and air permeable.

[0061] The first aspect, wherein the bendable solid cellulose foam comprises an upper surface and a lower surface, at least one of the upper surface and the lower surface of the bendable solid cellulose foam including at least one cut line of a predetermined cut depth DC, the at least one cut line being positioned to partially cut the cellulose foam, will now be described in detail with reference to the accompanying drawings.

[0062] Figures 1a and 1b show a top perspective side view of a first embodiment of the bendable solid cellulose foam 1. In Figure 1a, the cellulose foam is shown in an unfolded state, and in Figure 1b, the cellulose foam 1 is shown in a folded state.

[0063] The foldable solid cellulose foam has the shape of a plank and comprises an upper surface 11 and a lower surface 12 , two long sides 16 and two short sides 17 .

[0064] The sides 16, 17 have a height h, which preferably corresponds to the thickness T of the solid cellulose foam 1. The long side 16 and the short side 17 are rectangular surfaces 16, 17 defined by respective lengths L16, L17 and the height h, which are greater than the height h.

[0065] According to the invention, the cellulose foam 1 comprises at least one cutting line 2 having a predetermined cutting depth DC, the at least one cutting line 2 being arranged in the direction of the thickness T.

[0066] In the embodiment shown in FIG. 1a, the upper surface 11 comprises two cutting lines 2, namely a first cutting line 21 and a second cutting line 22, of respective predetermined cutting depths DC1, DC2, which are arranged to cut partially through the cellulose foam 1.

[0067] In the illustrated embodiment, the cut lines 21, 22 are positioned to extend from one long side 16 to the other long side 16. The cut lines 21, 22 are further positioned parallel to the short side 17 of the cellulose foam 1. The cut lines 21, 22 have respective cut lengths LC1, LC2 equal to the length L17 of the short side 17 such that the cut lines 21, 22 also cut partially through the long side 16 to the same predetermined cut depths DC1, DC2.

[0068] The cutting lines 21, 22 are arranged so as not to cut through the foam 1. This means that the predetermined cutting depths DC1, DC2 are less than the thickness T of the cellulose foam 1.

[0069] The cutting lines 21, 22 are positioned within the cellulose foam 1 such that the cutting lines 21, 22 cut through the upper surface 11 and further cut into the core C of the foam in a direction toward the lower surface 12 and in the thickness direction of the foam 1 as described above.

[0070] 1a, the cutting lines 21, 22 are shown to be arranged to extend in the Y / Z plane in the X / Y / Z space, and are linear cutting lines that each form a flat cut in the foam 1.

[0071] The cutting lines 21 and 22 divide the cellulose foam 1 into three portions P1, P2, and P3, with the first portion P1 being formed by the first cutting line 21 and one of the short sides 17. The second portion P2 is formed by the second cutting line 22 and the other short side 17, and the third portion P3 is formed between the first cutting line 21 and the second cutting line 22.

[0072] The cutting lines 21, 22 are positioned so that they do not cut all the way through the cellulose foam 1 but terminate before reaching the lower surface 12, leaving two remaining uncut portions RUP1, RUP2 (shown in FIG. 1b) within the cellulose foam 1. The two remaining uncut portions RUP1, RUP2 are located between the locations where the cutting lines 21, 22 each terminate and the lower surface 12, and extend within the Y / Z plane.

[0073] The remaining uncut portions RUP1, RUP2 each have a thickness TRUP1, TRUP2 (not shown) in the Y direction equal to the thickness T of the cellulose foam minus the predetermined cutting depths DC1, DC2 of the cutting lines 21, 22.

[0074] Furthermore, each of the remaining uncut portions RUP1, RUP2 has an extension parallel to the cut lengths LC1, LC2 and extends from one of the long sides 16 to the other of the long sides 16.

[0075] By positioning the cutting lines 21, 22 so that they do not cut all the way through the cellulose foam 1 but terminate before reaching the underside 12, thereby leaving the remaining uncut portions RUP1, RUP2, the remaining uncut portions RUP1, RUP2 form first and second hinges H1, H2, respectively, along which the cellulose foam 1 is folded.

[0076] The first portion P1 may be folded about the first hinge H1, and the second portion P2 may be folded about the second hinge H2.

[0077] Each hinge H1, H2 includes a respective folding axis FA1, FA2 about which the cellulose foam 1 can be folded. The folding axes FA1, FA2 extend in the Z direction within the cellulose foam 1. In the embodiment shown in Figure 1a, the folding axes FA1, FA2 are parallel to the length of the short sides 16, 17 and the cutting lines 21, 22.

[0078] Preferably, the predetermined cutting depth DC of the at least one cutting line is 99% or less of the thickness T of the cellulose foam, preferably 80% or more of the thickness T of the cellulose foam, more preferably 90% or more, and most preferably 90 to 99%.

[0079] As mentioned above, in Figure lb the cellulose foam 1 is shown in a folded state: the first part P1 is folded around the first hinge H1 towards the lower surface 12, and the second part P2 is folded around the second hinge H2 towards the lower surface 12. The third part P3 forms the bottom, and the first and second parts P1, P2 form the top of the folded cellulose foam 1.

[0080] In the folded state, the cutting lines 21, 22 form two cut surfaces: a first cut surface 210 and a second cut surface 220. The cut surfaces 210, 220 form new short sides 17. For the sake of accuracy, it should be pointed out that due to the folding of the cellulose foam 1, the short sides 17 may now be longer than the folded long sides 16.

[0081] In embodiments of the invention that include two or more cut lines, the cut lines may have equal or different predetermined cut depths DC. In the embodiment shown in Figure 1a, the two cut lines 21, 22 have equal predetermined cut depths DC1, DC2.

[0082] The at least one cutting line is arranged to cut into the cellulose foam 1 at a cutting angle CA relative to the at least one of the upper surface 11 and the lower surface 12. The angle chosen depends on the situation, for example the shape of the object to be protected by the bendable solid cellulose foam. In Figures 1a-1b, the cutting lines 21, 22 are arranged to cut into the cellulose foam 1 at a cutting angle perpendicular to the cellulose foam 1.

[0083] It may be preferable that at least the lower surface 12 comprises a densified outer layer 120. The two single cutting lines 21, 22 are then arranged so as not to cut all the way through the densified outer layer 120, or at least to cut only a small portion of the densified outer layer 120, so that the two remaining uncut portions RUP1, RUP2 comprise the densified outer layer that forms the at least one hinge H, i.e., in this embodiment the two hinges H1, H2.

[0084] In some embodiments, there is no sharp, distinct boundary between the core C and the densified outer layer 110, 120. Instead, there is a gradual transition from the core C to the densified outer layer 110, 120, just as the core C gradually transitions into the densified outer layer 110, 120. In these embodiments, the at least one cut line 2 may cut through only a portion of the transition from the core C to the densified outer layer 110, 120, but is positioned so as not to cut through the densified outer layer 110, 120, or at least to cut through only a small portion of the densified outer layer 110, 120.

[0085] In some embodiments, it may be preferred that not only the lower surface 12 includes the densified outer layer 120, but also the upper surface 11 includes the densified outer layer 110. In such embodiments, the cut lines 21, 22 cut through the densified outer layer 110 on the upper surface 11, but do not cut through the densified outer layer 120 on the lower surface 12.

[0086] Figure 2a shows in a perspective side view a second embodiment of the foldable solid cellulosic foam 1. The cellulose foam 1 is shown in an unfolded state.

[0087] What has been said with respect to Figures 1a-1b also applies to Figures 2a-2c and will not necessarily be repeated hereafter.

[0088] The cutting line 2 shown in Figure 2a is disposed within the upper surface 11 and the core C, further towards the lower surface 12. As can be seen, the cutting line 2 is an angled cutting line 2 with eight perpendicular corners C1 to C8.

[0089] The cutting line 2 divides the cellulose foam 1 into two portions P1 and P2, with the first portion P1 being formed by the first cutting line 2 and one of the long sides 16. The second portion P2 is formed between the cutting line 2 and the other of the long sides 16. The terms "long side" and "short side" do not necessarily mean that the long side is longer than the short side. Depending on the dimensions of the cellulose foam 1, the opposite may be true.

[0090] The cut line 2 includes six cut line segments 23. All six cut line segments 23 have a predetermined cut depth DC equal to the thickness T of the cellulose foam. This means that the six cut line segments 23 are through-cut lines 23. Three of the six through-cut lines 23 form first protruding portions PP1 included in the first portion P1, and the other three of the six through-cut lines 23 form second protruding portions PP2 included in the second portion P2. Each pair of the through-cut lines 23 separates protruding portions PP1, PP2 from the cellulose foam 1, making the protruding portions P1, P2 removable, as described further below.

[0091] The cutting line 2 further includes three cutting line portions 21 arranged to cut partially through the cellulose foam 1, and the three cutting line portions 21 have a predetermined cutting depth DC that is smaller than the thickness T of the cellulose foam 1. As a result, three remaining uncut portions RUP1, RUP2, and RUP3 are formed between the three cutting line portions 21 and the lower surface 12. Each of the three remaining uncut portions RUP1, RUP2, and RUP3 forms a respective hinge H1, H2, and H3 that includes a common folding axis FA along which the cellulose foam 1 is folded.

[0092] In some embodiments, the lower surface 12 includes a densified outer layer 120. The three cut line portions 21 positioned to cut partially through the cellulose foam 1 are, in these embodiments, positioned to extend in a direction from the upper surface 11 toward the lower surface 12, into the core C between the upper and lower surfaces 11, 12, and toward the densified outer layer 120 on the lower surface 12. The three cut line portions 21 are further positioned to not cut through the densified layer 120 but to terminate before the densified outer layer 120, such that the three remaining uncut portions RUP1, RUP2, RUP3 include the densified outer layer 120, and the three remaining uncut portions RUP1, RUP2, RUP3 and the densified outer layer 120 form the three hinges H1, H2, H3.

[0093] The combination of hinges H1, H2, H3 and detachable protruding portions PP1, PP2 makes the cellulose foam 1 foldable.

[0094] The folding of the cellulose foam 1 is performed by folding one of the two parts P1, P2 around the folding axis FA using the hinges H1, H2, H3. As described above, the protruding parts PP1, PP2 are removably arranged by the through-cut line 23. Therefore, when one of the two parts P1, P2 is folded around the folding axis FA, the first protruding part PP1 is removed from the second part P2, and the second protruding part PP2 is removed from the first part P1.

[0095] 2b shows the foldable cellulose foam 1 in a folded state, where one or both of the first and second portions P1 and P2 of the cellulose foam 1 are folded at a folding angle A. In the illustrated embodiment, the folding angle A is 90°, and the first and second portions P1 and P2 together form a perpendicular corner that can be used, for example, as corner protection.

[0096] When the cellulose foam 1 is folded, the first and second protruding portions PP1 and PP2 form the outer sides of the corner (best seen in FIG. 2c). The corner includes two edges, a first edge E1 and a second edge E2, where the first edge E1 is part of the first protruding portion PP1 and the second edge E2 is part of the second protruding portion PP2. In this manner, the protruding portions PP1 and PP2 and their respective edges E1 and E2 help stabilize the corner and improve its mechanical properties, such as impact resistance.

[0097] This structural design of the corners allows the entire bendable cellulose foam to be used, with no waste in between.

[0098] As can be seen from Figures 2b to 2c, the first protruding portion PP1 forms a void V2 corresponding to the second portion P2 of the foam 1, and the second protruding portion PP2 forms a void V1 corresponding to the first portion P1 when the cellulose foam 1 is in a folded state.

[0099] The protruding portions PP1, PP2 each include a surface S1, S2 formed by a through cut line 23.

[0100] The lower surface 12 of the cellulose foam 1 forms the inside of the corner and faces the corner of the product to be protected, while the outer surface of the corner is formed by the upper surface 11 and the surfaces S1, S2 of the protruding portions PP1, PP2.

[0101] In a preferred embodiment of the present invention, at least one of the upper surface 11 and the lower surface 12 of the solid cellulose foam comprises a densified outer layer 110,120.

[0102] In some embodiments, the at least one cut line 2 is positioned to cut through one of the upper surface 11 and the lower surface 12 into the core C and all the way down to, but not through, the densified outer layer 110, 120 of the other of the at least one of the upper surface 11 and the lower surface 12, such that the at least one remaining uncut portion RUP is the densified outer layer 110, 120 forming the at least one hinge H. The predetermined cut depth DC, in these embodiments, can be formulated as the thickness T of the cellulose foam 1 minus the thickness of the densified outer layer 110, 120 of the other of the at least one of the upper surface 11 and the lower surface 12.

[0103] Preferably, both the upper surface 11 and the lower surface 12 comprise the densified outer layer 110,120.

[0104] Embodiments are envisaged in which the at least one cutting line 2 is arranged to cut into the material at a cutting angle CA arranged to cut obliquely rather than perpendicularly to the upper or lower surface, which may in these embodiments be less than or greater than 90°.

[0105] In embodiments in which the at least one cutting line 2 is disposed diagonally into at least one of the upper surface 11 and the lower surface 12 and further into the foam 1, it will be understood that the predetermined cutting depth DC is a component of the cutting length vector of the diagonal cutting line, whereby the component has the same direction as the thickness T (and often the height h) of the foam.

[0106] The at least one cutting line 2 may further be arranged vertically, horizontally or in a direction between vertical and horizontal on at least one of the upper surface 11 or lower surface 12. The direction selected depends on the shape of the object to be protected by the foldable solid cellulose foam 1.

[0107] It should also be understood that the at least one cutting line 2 is positioned to cut through at least one of the upper surface 11 and the lower surface 12 from one of the long sides 16 to the other of the long sides 16 or from one of the short sides 17 to the other of the short sides 17, so that the associated side 16, 17 is also cut to a predetermined cutting depth DC that is the same as the predetermined cutting depth cutting through the upper and / or lower surfaces 11, 12.

[0108] By positioning the at least one cut line 2 to extend from one side surface 16, 17 to the opposite side surface 16, 17 and cut through at least one of the upper or lower surfaces 11, 12, and through the one side surface 16, 17 and the opposite side surface 16, 17, but not through the other of the upper or lower surfaces 11, 12, the cellulose foam 1 is provided with at least one remaining uncut portion RUP that extends from the one side surface 16, 17 all the way to the opposite side surface 16, 17, thereby providing the cellulose foam 1 with at least one hinge H. The at least one hinge H thereby extends from the one side surface 16, 17 all the way to the opposite side surface 16, 17. This allows the cellulose foam 1 to be folded around the at least one hinge H.

[0109] In an embodiment in which the at least one cutting line 2 is arranged to extend from one long side 16 to the other long side 16, the at least one cutting line 2 is preferably arranged parallel to the short side 17 and has a cutting length LC equal to the length L17 of the short side 17.

[0110] In an embodiment in which the at least one cutting line 2 is arranged to extend from one short side 17 to the other short side 17, the at least one cutting line 2 is preferably arranged parallel to the long side 16 and has a cutting length LC equal to the length L16 of the long side 16.

[0111] When the at least one cutting line 2 is arranged parallel to either the long side 16 or the short side 17, the at least one cutting line 2 intersects the angle between the upper or lower surface 11, 12 and the long side 16 or the short side 17 at a right angle.

[0112] In some embodiments, two or more cutting lines 2 are arranged on at least one of the upper and lower surfaces 11, 12.

[0113] The foldable solid cellulose foam 1 may preferably have a flat surface.

[0114] Preferably, at least one of the upper and lower surfaces 11, 12 is a flat surface, and the at least one cutting line 2 is located on the flat surface.

[0115] It should be understood that the at least one cutting line 2 is arranged to extend in a direction from at least one edge of the upper and lower surfaces 11, 12 to the other edge thereof, and therefore the at least one cutting line 2 also cuts the at least one side surface 16, 17.

[0116] The height h of the at least one side surface 16, 17 may be related to the thickness T of the foam 1 as previously described.

[0117] The height of the at least one side surface 16, 17 may be very low relative to the upper and lower surfaces 11, 12. An example of a cellulose foam 1 having a low height relative to the upper and lower surfaces 11, 12 is a cellulose foam plank.

[0118] An example of a flat surface may be the surface of the solid cellulose foam plank.

[0119] In some embodiments, both the upper surface 11 and the lower surface 12 of the cellulose foam 1 include at least one cut line 2 of a predetermined cut depth DC.

[0120] The at least one cutting line 2 on the upper surface 11 and the at least one cutting line 2 on the lower surface 12 may have the same direction or may have different directions.

[0121] It is further conceivable that at least one of the upper and lower surfaces 11, 12 comprises at least two cutting lines 2 of different directions.

[0122] It is contemplated that the densified outer layers 110, 120 may have different thicknesses depending on which surface the densified outer layers 110, 120 are disposed on. It is further contemplated that the densified outer layers 110, 120 may have the same thickness regardless of which surface the densified outer layers 110, 120 are disposed on.

[0123] In the second aspect, a method for producing the foldable solid cellulose foam 1 material is now described.

[0124] The method comprises: - providing a solid cellulose foam 1 having an upper surface 11 and a lower surface 12; - placing at least one cutting line 2 of a predetermined cutting depth DC on at least one of said upper surface 11 and said lower surface 12, thereby further positioning said at least one cutting line 2 so as to cut partially through said solid cellulose foam 1; Includes.

[0125] The cut is made by providing a cutting tool and positioning it in contact with the at least one of the upper surface 11 and the lower surface 12. The cutting tool is then pressed into the at least one of the upper surface 11 and the lower surface 12 and further into the core C of the cellulose foam 1, thereby positioning the at least one cut line 2, 21, 22 to cut partially through the cellulose foam 1.

[0126] The cutting operation is completed when the at least one cutting line 2 cuts partially through the solid cellulose foam 1 such that the predetermined cutting depth DC is smaller than the thickness T of the cellulose foam, thereby positioning at least one remaining uncut portion RUP between the at least one cutting line 2 and the other of the at least one of the upper surface 11 and the lower surface 12.

[0127] The at least one remaining uncut portion RUP has a thickness TRUP equal to the thickness T of the cellulose foam 1 minus the predetermined cutting depth DC of the cutting line 2, and the at least one remaining uncut portion RUP forms at least one hinge H along which the cellulose foam 1 is folded.

[0128] The predetermined cutting depth DC of the at least one cutting line is arranged so as to be 99% or less of the thickness T of the cellulose foam, preferably 80% or more of the thickness T of the cellulose foam 1, more preferably 90% or more, and most preferably 90 to 99%.

[0129] Preferably, at least one of the upper or lower surfaces 11,12 of the solid cellulose foam 1 is arranged to include a densified outer layer 110,120.

[0130] The cutting tool further arranges the at least one cutting line 2 to extend from one of the upper surface 11 and the lower surface 12 to the core C between the upper surface and the lower surface 11, 12 and toward the densified outer layer 110, 120 of the other of the upper surface 11 and the lower surface 12, and arranges the at least one cutting line 2 to not cut through the densified layer 110, 120 but to terminate before the densified layer 110, 120 so that the at least one remaining uncut portion RUP includes the densified outer layer 110, 120. The at least one remaining uncut portion RUP and the densified outer layer 110, 120 thereby form the at least one hinge H.

[0131] The at least one cutting line 2 is arranged to be a straight cutting line, a curved cutting line, an angled cutting line including at least one angle, an irregularly shaped cutting line, or any combination thereof.

[0132] The at least one cutting line 2 may further be arranged to include at least one portion having a predetermined cutting depth DC that is smaller than the thickness T of the cellulose foam 1, and at least one portion having a predetermined cutting depth DC that is equal to the thickness T of the cellulose foam 1.

[0133] The foldable solid cellulose foam 1 may be arranged to include at least one cut line 2 having a predetermined cut depth DC equal to the thickness T of the cellulose foam.

[0134] The at least one cut line 2 arranged to cut through the foam 1 may be arranged to be a straight cut line, a curved cut line, an angled cut line comprising at least one angle, a cut line forming a closed loop, an irregularly shaped cut line, or any combination thereof.

[0135] The method further comprises positioning the at least one cutting line (2) to cut partially into the solid cellulose foam (1) in a direction perpendicular to at least one of the upper surface (11) and the lower surface (12).

[0136] In some embodiments, the at least one cutting line 2 is positioned to cut partially into the solid cellulose foam 1 at an angle relative to the upper surface 11 or the lower surface 12, the angle being less than 90° or greater than 90°.

[0137] In another embodiment of the method, the at least one cutting line 2 is arranged to cut diagonally into the foam 1. The at least one cutting line 2 cuts into the foam 1 at a cutting angle CA relative to the top or bottom surface, the cutting angle CA being less than 90° or greater than 90°.

[0138] The at least one cutting line 2 is arranged to extend in a direction from one edge of the respective upper or lower surface 11, 12 towards the opposite edge, the at least one cutting line thereby forming an angle EA with the edge.

[0139] In some embodiments, the method further comprises arranging at least one cut line 2 of a predetermined cut depth DC on both the upper surface 11 and the lower surface 12. It is understood that the predetermined cut depth DC may be the same on both sides of the foam 1 or may be different on the different surfaces 11, 12. It is also understood that the at least one cut line 2 on the upper surface 11 and the at least one cut line 2 on the lower surface 12 may be arranged to have the same direction or to have different directions.

[0140] The method further comprises disposing at least one of the upper surface 11 or the lower surface 12 of the solid cellulose foam 1 to include the densified outer layer 110, 120, and preferably disposing both of the at least one of the upper surface 11 or the lower surface 12 to include the densified outer layer 110, 120.

[0141] In some embodiments, the method includes positioning the at least one cut line 2 to cut through one of the upper surface 11 and the lower surface 12 into the core C and all the way to, but not through, the densified outer layer 110, 120 of the other of at least one of the upper surface 11 and the lower surface 12, such that the at least one remaining uncut portion RUP is the densified outer layer 110, 120 forming the at least one hinge H. The predetermined cut depth DC, in these embodiments, can be formulated as the thickness T of the cellulose foam 1 minus the thickness of the densified outer layer 110, 120 of the other of at least one of the upper surface 11 and the lower surface 12.

[0142] Materials and Material Properties The cellulose fibers contained in the solid cellulose foam are preferably selected from wood pulp, regenerated cellulose fibers, and vegetable fibers, preferably softwood pulp, chemithermomechanical pulp (CTMP), and dissolving pulp, or a combination thereof.

[0143] The solid cellulose foam preferably comprises: a)) 71 to 95 wt. % cellulose fibers calculated based on the total weight of the solid content of the foam; b) 4 to 24% by weight of a water-soluble thickener calculated based on the total weight of the solid content of the foam; c) at least two surfactants; Includes.

[0144] The density of the solid cellulose foam is 10 to 80 kg / m 3 , preferably 10 to 60 kg / m 3 , more preferably 20 to 50 kg / m 3 The interval can be:

[0145] At least one of the upper surface or the lower surface of the solid cellulose foam comprises a densified outer layer. Preferably, both the upper surface and the lower surface comprise a densified outer layer.

[0146] The cellulose foam may have a thickness lying in the interval between 5 and 200 mm, more preferably between 10 and 100 mm, or between 10 and 50 mm.

[0147] An example of a possible size is a solid cellulose foam plank having a thickness of 40 to 60 mm, preferably about 50 mm.

[0148] The dimensions stated above serve as examples only and should not be considered to limit the products of the present invention to the dimensions stated above.

[0149] The foldable solid cellulose foam may include compressed regions and through cuts that form through holes.

[0150] The volume of the through cut serves as a housing for enclosing the product, while the partial cut defines a surface that is then pressed to form a compressed area. The volume of the compressed area also serves as a housing for the product to be packaged and protected. Thus, no waste is generated by placing a housing within the solid cellulose foam.

[0151] The partial cut allows for perfect positioning of the product, adding important additional protection to the package. The pressed details in the solid cellulose foam ensure precise positioning of the heaviest and / or most vulnerable parts of the item, ensuring they are held in place.

[0152] Compressing well-defined portions of the solid cellulose foam into a denser, compressed material increases the stiffness and resilience of the solid cellulose foam in those portions, which provides a means for holding the product in place within the protective packaging insert.

[0153] The cellulose foam plank section may be folded towards the product so that the cut or compressed section of the solid cellulose foam plank is in direct contact with the product. The very good cushioning capacity of the solid cellulose foam plank effectively protects the product, and the cut or compressed section fixedly positioned on the substrate helps to position the item during insertion and provide additional protection.

[0154] At least one of the upper surface and the lower surface may be a curved surface.

[0155] The terms "long side" and "short side" are merely illustrative of terms used in connection with the drawings, and it should be understood that the at least one cutting line may be oriented parallel, substantially parallel, or at an angle to either the long side or the short side.

[0156] As will be appreciated by those skilled in the art, many variations and modifications can be made to these and other embodiments of the present invention without departing from the scope of the invention, which is defined in the appended claims.

[0157] It should be noted that the above aspect may be the subject of its own protection, such as in a separate divisional application. It is therefore anticipated that this aspect of the invention may require its own protection, for example because it may be essentially applicable to concepts other than those defined by the independent claims of the present application.

Claims

1. A foldable solid cellulose foam, the foldable solid cellulose foam comprising an upper surface (11) and a lower surface (12), wherein at least one of the upper surface (11) and the lower surface (12) of the foldable solid cellulose foam (1) comprises at least one cutting line (2) of a predetermined cutting depth (DC), and the at least one cutting line (2) is arranged to partially penetrate and cut through the cellulose foam (1).

2. The foldable solid cellulose foam according to claim 1, wherein the predetermined cutting depth (DC) is smaller than the thickness (T) of the cellulose foam (1) between the upper surface and the lower surface (11, 12).

3. The foldable solid cellulose foam according to claim 1, wherein the cellulose foam (1) further comprises two long sides (16) and two short sides (17), and the at least one cutting line (2) is arranged to also cut the two long sides (16) or the two short sides (17).

4. The foldable solid cellulose foam according to claim 1, wherein at least one remaining uncut portion (RUP) is located between the at least one cut line (2) and the other of the top surface (11) and the bottom surface (12) that include the at least one cut line, and the at least one remaining uncut portion (RUP) forms at least one hinge (H) for folding the cellulose foam (1).

5. The foldable solid cellulose foam according to claim 1, wherein the predetermined cutting depth (DC) of the at least one cutting line is 99% or less of the thickness (T) of the cellulose foam (1), preferably 80% or more, more preferably 90% or more, and most preferably 90-99% of the thickness (T) of the cellulose foam (1).

6. The foldable solid cellulose foam according to claim 1, wherein at least one of the upper surface (11) and the lower surface (12) of the solid cellulose foam (1) includes a densified outer layer (110, 120).

7. The foldable solid cellulose foam according to claim 6, wherein the at least one cutting line (2) is positioned to extend from one of the upper surface (11) and the lower surface (12) into the core (C) between the upper surface (11) and the lower surface (12), and toward the densified outer layer (110, 120) on the other of the upper surface (11) and the lower surface (12), and the at least one cutting line (2) is positioned not to cut through the densified layer (110, 120) so that the at least one remaining uncut portion (RUP) includes the densified outer layer (110, 120).

8. The foldable solid cellulose foam according to claim 1, wherein the at least one cutting line (2) is a straight cutting line, a curved cutting line, an angled cutting line including at least one angle, an irregularly shaped cutting line, or any combination thereof.

9. The foldable solid cellulose foam according to claim 1, wherein the at least one cutting line (2) includes at least one portion (21, 22) having a predetermined cutting depth (DC1, DC2) smaller than the thickness (T) of the cellulose foam, and at least one portion (23) having a predetermined cutting depth equal to the thickness (T) of the cellulose foam (1).

10. The foldable solid cellulose foam according to claim 1, wherein the at least one cutting line (2) is positioned to partially cut into the cellulose foam in a direction perpendicular to at least one of the upper surface (11) and the lower surface (12).

11. The density of the solid cellulose foam (1) is 10 to 80 kg / m³. ３ Preferably 10 to 60 kg / m ３ A foldable solid cellulose foam according to claim 1, which is within the range.

12. The aforementioned solid cellulose foam, a) Based on the total weight of the solid content of the foam, 71 to 95% by weight of cellulose fibers, b) A water-soluble thickener in an amount of 4 to 24% by weight, calculated based on the total weight of the solid content of the foam, c) at least two surfactants and A foldable solid cellulose foam according to claim 1, comprising:

13. A method for producing a foldable solid cellulose foam, - A step of providing a solid cellulose foam (1) including an upper surface (11) and a lower surface (12), - A step of arranging at least one cutting line (2) with a predetermined cutting depth (DC) on at least one of the upper surface (11) and the lower surface (12), thereby arranging the at least one cutting line (2) to partially penetrate and cut through the solid cellulose foam (1). Methods that include...

14. The method according to claim 13, wherein the at least one cutting line (2) is positioned to partially penetrate and cut through the solid cellulose foam (1) such that the predetermined cutting depth (DC) is less than the thickness (T) of the cellulose foam (1) between the upper surface and the lower surface (11, 12).

15. The method according to claim 13, wherein at least one remaining uncut portion (RUP) is located between the at least one cut line (2) and the other of at least one of the upper surface (11) and lower surface (12) of the foldable solid cellulose foam (1) including the at least one cut line (2), the at least one remaining uncut portion (RUP) forms at least one hinge (H) for folding the cellulose foam (1).

16. The method according to claim 13, wherein the predetermined cutting depth (DC) of the at least one cutting line (2) is 99% or less of the thickness T of the cellulose foam, preferably 80% or more of the thickness T of the cellulose foam (1), more preferably 90% or more, and most preferably 90-99%.

17. The method according to claim 13, wherein at least one of the upper surface (11) or the lower surface (12) of the solid cellulose foam (1) is arranged to include a densified outer layer (110, 120).

18. The method according to claim 17, wherein the at least one cutting line (2) is positioned to extend from one of the upper surface (11) and the lower surface (12) into the core (C) between the upper surface and the lower surface (11, 12) and toward the densified outer layer (110, 120) on the other of the upper surface (11) and the lower surface (12), and the at least one cutting line (2) is positioned not to cut through the densified outer layer (110, 120) such that the at least one remaining uncut portion (RUP) includes the densified outer layer (110, 120).

19. The method according to claim 13, wherein the at least one cutting line (2) is arranged to be a straight cutting line, a curved cutting line, an angled cutting line including at least one angle, an irregularly shaped cutting line, or any combination thereof.

20. The method according to claim 13, wherein the at least one cutting line (2) is arranged to include at least one portion having a predetermined cutting depth (DC) smaller than the thickness (T) of the cellulose foam and at least one portion having a predetermined cutting depth (DC) equal to the thickness (T) of the cellulose foam.

21. The method according to claim 13, wherein the at least one cutting line (2) is positioned to partially cut into the solid cellulose foam (1) in a direction perpendicular to at least one of the upper surface (11) and the lower surface (12).

22. The method according to claim 13, wherein the at least one cutting line (2) is positioned to partially cut into the solid cellulose foam (1) at an angle to the upper surface (11) or the lower surface (12), and the angle is less than 90° or greater than 90°.

23. The density of the solid cellulose foam (1) is 10 to 80 kg / m³. ３ Preferably 10 to 60 kg / m ３ The method according to claim 13, which is within the range of the present invention.

24. The solid cellulose foam material (1) a) Based on the total weight of the solid content of the foam, 71 to 95% by weight of cellulose fibers, b) A water-soluble thickener in an amount of 4 to 24% by weight, calculated based on the total weight of the solid content of the foam, c) at least two surfactants and The method according to claim 13, including the method described in claim 13.

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