Recyclable bonded air-laid blanks

Abstract

A method of producing a bonded air-laid blank (10) comprises introducing a cellulose and / or lignocellulose material and a polymer binder into a forming head (110). The cellulose and / or lignocellulose material comprises a recycled cellulose and / or lignocellulose material and defibrated pulp. The method also comprises capturing the cellulose and / or lignocellulose material and the polymer binder as an unbonded air-laid web (20) on a conveyor (120) arranged in connection with an outlet (113) of the forming head (110), and heating the unbonded air-laid web (20) to at least partly melt the polymer binder and bind the cellulose and / or lignocellulose material to form a bonded air-laid blank (10) comprising less than 10 % by weight of the polymer binder and at least 80 % by weight of the cellulose and / or lignocellulose material.

Description

[0001] RECYCLABLE BONDED AIR-LAID BLANKS

[0002] TECHNICAL FIELD

[0003] The present invention generally relates to bonded air-laid blanks, and to recyclable bonded air-laid blanks and to a method for producing such bonded air-laid blanks.

[0004] BACKGROUND

[0005] With growing awareness for the environment and humanly induced climate change, the use of plastic insulation and / or cushioning products has come more and more into question. However, despite this concern the use of these products has grown vastly with new trends in lifestyles and consumer habits of the last decade. One reason for this is that more and more goods are transported around the globe and these goods need protection against impact or shock and / or extreme temperatures. A common way of protecting the goods is to include cushioning and / or insulating products, such as inserts of suitable form into the packaging. These can be made from different materials but are typically made from a foamed polymer, of which expanded polystyrene (EPS) is by far cheapest and most common. In some cases, the entire packaging can be made out of EPS. EPS is, however, one of the most questioned plastic materials and many brand owners are looking for more sustainable solutions for these packaging applications.

[0006] There is therefore a need for alternative materials that could replace the plastic insulation and / or cushioning products. A bonded air-laid blank, sometimes also referred to as bonded dry-laid blank, dry- formed blank, air-laid batt, dry-laid batt, air-laid mat, or dry-laid mat, is formed by a process known as airlaying, in which cellulose and / or lignocellulose fibers and a polymer binder are mixed with air to form a porous fiber mixture deposited onto a support and consolidated or bonded by heating. During the heating the cellulose and / or lignocellulose fibers are bonded by the polymer binder. The bonded air-laid blank is characterized by being porous, having the character of an open cell foam. Bonded air-laid blanks are produced in a so-called dry forming method, i.e., generally without addition of water. The air-laying process is described in, for instance, U.S. patent no. 6,233,787. The characteristics of bonded air-laid blanks make them suitable for the production of insulation and / or cushioning products.

[0007] Commonly, virgin pulp is used as a source for the cellulose and / or lignocellulose fibers in the air-laying process. These materials, however, demand a comparatively high amount of polymer binder to keep the cellulose and / or lignocellulose fibers together in the bonded air-laid blank. The high amount of polymer binder in the bonded air-laid blank may make recycling of the products produced from the bonded air-laid blank difficult in existing recycling streams. There is therefore a need for bonded air-laid blanks that can be more easily recycled.

[0008] US 8,318,062 B2 and US 8,973,762 B2 disclose an industrial absorbent and methods of manufacturing the same. The industrial absorbent includes a first scrim made from at least one thermoplastic material, a second scrim made from at least one thermoplastic material and a middle layer positioned between the first and second scrims. The middle layer includes a dry-laid web of fire-retardant treated cellulose and opened, individuated staple bicomponent fiber. At least some of the bicomponent fiber in the middle layer is thermally bonded to at least some of the cellulose in the middle layer, and the first and second scrims are thermally bonded to the middle layer.

[0009] SUMMARY

[0010] It is a general objective to provide recyclable bonded air-laid blanks.

[0011] It is another general objective to provide non- or low-linting bonded air-laid blanks.

[0012] These and other objectives are met by embodiments disclosed herein.

[0013] The present invention is defined in the independent claims. Further embodiments of the invention are defined in the dependent claims.

[0014] An aspect of the invention relates to a method of producing a bonded air-laid blank. The method comprises introducing cellulose and / or lignocellulose material and a polymer binder into a forming head. The cellulose and / or lignocellulose material comprises a recycled cellulose and / or lignocellulose material and defibrated pulp. The method also comprises capturing the cellulose and / or lignocellulose material and the polymer binder as an unbonded air-laid web on a conveyor arranged in connection with an outlet of the forming head. The method further comprises heating the unbonded air-laid web to at least partly melt the polymer binder and bind the cellulose and / or lignocellulose material to form a bonded air-laid blank comprising less than 10 % by weight of the polymer binder and at least 80 % by weight of the cellulose and / or lignocellulose material.

[0015] Another aspect relates to a bonded air-laid blank comprising at least 80 % by weight of a cellulose and / or lignocellulose material comprising a recycled cellulose and / or lignocellulose material and defibrated pulp. The bonded air-laid blank also comprises less than 10 % by weight of a polymer binder binding together the cellulose and / or lignocellulose material and the defibrated pulp.

[0016] The present invention produces bonded air-laid blanks with a comparatively low amount of polymer binder by using a mixture of defibrated pulp and recycled cellulose and / or lignocellulose material. The recycled cellulose and / or lignocellulose material contains less dusting fines and small particles than traditional cellulose and / or lignocellulose materials used in air-laying processes and thereby have a lower tendency to dust or lint. The defibrated pulp is included to build up the porosity of the produced bonded air-laid blank and thereby contribute to the cushioning and / or insulating capacity of the bonded air-laid blank. The mixture of defibrated pulp and recycled cellulose and / or lignocellulose material having lower amount of fines and dusting particles means that less polymer binder is needed to capture such fines and dusting particles in the bonded air-laid blank. This means that the bonded air-laid blank and products produced therefrom can be more easily recycled, such as in paper recycling streams, due to the low content of polymer binder.

[0017] BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The embodiments, together with further objects and advantages thereof, may best be understood by making reference to the following description taken together with the accompanying drawings, in which:

[0019] Fig. 1 is a perspective view of a bonded air-laid blank according to an embodiment;

[0020] Fig. 2 schematically illustrates a cellulose and / or lignocellulose material flake;

[0021] Fig. 3 is a flow chart illustrating a method of producing an air-laid blank according to an embodiment;

[0022] Fig. 4 is a flow chart illustrating additional, optional steps of the method in Fig. 3 according to various embodiments; and

[0023] Fig. 5 is a schematic illustration of a system for producing an air-laid blank according to various embodiments.

[0024] DETAILED DESCRIPTION

[0025] The present invention generally relates to bonded air-laid blanks, and to recyclable bonded air-laid blanks and to a method for producing such bonded air-laid blanks. Bonded air-laid blanks are characterized by being porous, having the character of an open cell foam. They are resilient and have great damping and insulation capacity. These characteristics of bonded airlaid blanks make the material suitable to replace polymer foams and formed in-place fossil-based materials in packaging solutions. A common way of protecting the goods is to include cushioning or insulation elements or products, such as inserts of suitable form into the packaging. These cushioning or insulation elements or products are typically made from a foamed petroleum-based polymer, of which expanded polystyrene (EPS) is by far cheapest and most common. EPS is, however, one of the most questioned plastic materials and many brand owners are looking for more sustainable solutions for these packaging applications. Bonded air-laid blanks are useful for production of more environmentally friendly replacements to corresponding cushioning inserts made of or from foamed polymers, for instance EPS or foamed polyurethane (PU). Bonded air-laid blanks also find uses where there is a need for providing insulation, such as thermal or sound insulation. Illustrative, but non-limiting examples, of such applications include thermal insulation of heated or cold food products or other articles that need to be kept within defined temperature ranges. Furthermore, sound absorbing panels or elements could be produced from the bonded air-laid blanks.

[0026] In the art, the cellulose and / or lignocellulose fiber material input into the forming head of an air-laying system is typically in the form of defibrated cellulose and / or lignocellulose fiber material made from virgin pulp. Such a defibrated cellulose and / or lignocellulose fiber material typically has the vast majority of the cellulose and / or lignocellulose fibers in the form of individual or free fibers. Such a cellulose and / or lignocellulose fiber material could be regarded as a virgin cellulose and / or lignocellulose fiber material since it is made directly from virgin pulp. The defibrated pulp, however, does not only contain the desired cellulose and / or lignocellulose fibers, but also fiber fragments and smaller particles commonly referred to as "fines” in the art. In the production of bonded air-laid blanks, non-bonded cellulose and / or lignocellulose fibers, fiber fragments and fines present on or in the bonded air-laid blanks or detached therefrom during production are perceived as lint or dust. This lint, to a major part, consists of cellulose and / or lignocellulose fibers, fiber fragments and fines that have not been sufficiently bonded by the polymer binder either on the surfaces or within the bonded air-laid blanks. The lint or dust may constitute aesthetic problems for products formed from the bonded air-laid blanks. Furthermore, in larger quantities, such dust can cause inconvenience and irritations for persons handling the bonded air-laid blanks during and following production. The lint or dust may also cause problems for electronics and electronic equipment if these are packaged using cushioning or insulation elements or inserts made by linting bonded air-laid blanks. In such a case, non-bonded cellulose and / or lignocellulose fibers, fiber fragments and fines may cause short circuits if reaching the electronic circuitry within the electronics or electronic equipment. Such non-bonded cellulose and / or lignocellulose fibers, fiber fragments and fines might also be a risk during operation of the electronics or electronic equipment causing heat development that might ignite the non-bonded cellulose and / or lignocellulose fibers, fiber fragments and fines.

[0027] A solution to such a linting problem in the art has been to use a comparatively high amount of polymer binder to bind and thereby capture the cellulose and / or lignocellulose fibers, fiber fragments and fines in the bonded air-laid blank. However, if the amount of the polymer binder used in the bonded air-laid blank is high then it is not straightforward to recycle the products produced from the bonded air-laid blanks. Thus, in order to promote repulpability of the bonded air-laid blanks and products produced therefrom in, for instance, board mills or in the paper recycling streams and thereby to increase the environmental friendliness of the bonded air-laid blanks and the products produced therefrom, the amount of polymer binder should be low. However, a low amount of polymer binder means that the linting tendency of the bonded air-laid blanks is generally increased significantly. In other words, there is a trade-off between recyclability and linting for the prior art bonded air-laid blanks.

[0028] The present invention has taken a radically different approach as compared to prior art bonded air-laid blanks and methods of producing such bonded air-laid blanks that reduces the linting problem but without the need for high amounts of polymer binder. This is possible by using a cellulose and / or lignocellulose material that not only comprises defibrated pulp but also recycled cellulose and / or lignocellulose material. Thus, the cellulose and / or lignocellulose material used according to the invention is a mixture of defibrated pulp and recycled, such as reclaimed or re-used, cellulose and / or lignocellulose material. For instance, recycled post-industrial and / or recycled post-consumer cellulose and / or lignocellulose material could be used as, or processed into, a recycled cellulose and / or lignocellulose material that could be used together with the defibrated pulp as a source for the cellulose and / or lignocellulose material for the bonded air-laid blank. Such a recycled cellulose and / or lignocellulose material has the advantage over defibrated cellulose and / or lignocellulose fiber material in terms of containing lower amount of fiber fragments and fines. Accordingly, lower amounts of polymer binder can be used to bind the cellulose and / or lignocellulose material in the produced bonded air-laid blank and still having no or at least a reduced linting as compared to prior art bonded air-laid blanks. The lower amount of polymer binder means that the bonded air-laid blank, and products produced therefrom, can more readily be recycled in existing recycling streams, including paper recycling streams. Another benefit of the bonded air-laid blanks and the cellulose and / or lignocellulose material used to produce the bonded air-laid blanks is that the cellulose and / or lignocellulose material is in the form of a mixture of defibrated pulp and recycled, reclaimed or re-used cellulose and / or lignocellulose material, sometimes referred to as non-virgin cellulose and / or lignocellulose material. This means that chips, clips, clippings, waste, trims, trimmings, leftovers and / or scraps of, for example, paper, printing paper, newsprint, paper board, corrugated board, cartonboard, liner and / or fluting, from a paper- and / or boardmaking, -using or -converting process or facility can be used as recycled cellulose and / or lignocellulose material. Alternatively, or in addition, recycled paper, printing paper, newsprint, paper board, corrugated board, cartonboard, liner and / or fluting could be used as recycled cellulose and / or lignocellulose material. Such a recycled cellulose and / or lignocellulose material is typically cheaper as compared to defibrated cellulose and / or lignocellulose fiber material as produced from virgin pulp.

[0029] The present invention therefore relates to a method of producing a bonded air-laid blank 10, see Figs. 1 , 3, and 5. The method comprises introducing, in step S1, cellulose and / or lignocellulose material and a polymer binder into a forming head 110. The cellulose and / or lignocellulose material comprises a recycled cellulose and / or lignocellulose material and defibrated pulp. The cellulose and / or lignocellulose material and the polymer binder are captured in step S2 as an unbonded air-laid web 20 on a conveyor 120 arranged in connection with an outlet 113 of the forming head 110. The method also comprises heating, in step S3, the unbonded air-laid web 20 to at least partly melt the polymer binder and bind the cellulose and / or lignocellulose material to form a bonded air-laid blank 10 comprising less than 10 % by weight of the polymer binder and at least 80 % by weight of the cellulose and / or lignocellulose material.

[0030] The heating as applied in step S3 will partly melt the polymer binder to become tacky and adhere to the cellulose and / or lignocellulose material in the unbonded air-laid web 20 to thereby form the bonded airlaid blank 10. Most of free cellulose and / or lignocellulose particles, including any fiber fragments and fines, in the unbonded air-laid web 20 will thereby be bonded together by the polymer binder forming the porous, open cell foam like structure of the bonded air-laid blank 10.

[0031] Fig. 1 schematically shows a bonded air-laid blank 10 produced by the method as shown in Fig. 3. As is shown in Fig. 1 , a bonded air-laid blank 10 is typically in the form of a sheet having a length L, a width W and a thickness T. Generally, lint and dust are present on and released from the surfaces 1 1, 12, 13, 14 of the bonded air-blank 10. Fig. 1 illustrates main surfaces 12, 14 of the bonded air-laid blank 10 that are the two surfaces defined by the length L and the width W. The main surfaces 12, 14 are substantially parallel with the upper surface of the conveyor 120 (Fig. 5) with one of the main surfaces 14 facing the conveyor 120 (Fig. 5) and being positioned thereon during production of the bonded air-laid blank 10 and with the other main surface 12 facing in a direction opposite to the conveyor 120 (Fig. 5). The main surfaces 12, 14 of the bonded air-laid blank 10 have a respective surface area that is typically substantially larger than the surface area of the longitudinal sides 11 or end sides 13 of the bonded airlaid blank 10.

[0032] In an embodiment, the recycled cellulose and / or lignocellulose material comprises cellulose and / or lignocellulose mainly in the form of cellulose and / or lignocellulose material flakes 30, preferably at least 75 % by weight of the recycled cellulose and / or lignocellulose material. Any remaining cellulose and / or lignocellulose in the recycled cellulose and / or lignocellulose material is typically in the form of cellulose and / or lignocellulose fibers, but may also include a smaller amount of fiber fragments and fines. However, the amount of such fiber fragments and fines is generally significantly lower in the recycled cellulose and / or lignocellulose material as compared to defibrated cellulose and / or lignocellulose fiber material, such as defibrated pulp. The reduced amount of polymer binder, i.e., less than 10 % by weight, used by the invention is sufficient to bind the cellulose and / or lignocellulose material flakes 30 and the defibrated pulp into a bonded air-laid blank 10 and still capture most of any fiber fragments and fines present in the cellulose and / or lignocellulose material. Thus, the bonded air-laid blanks 10 of the invention are more easily recycled due to the low amount of polymer binder, and still have reduced linting and dusting.

[0033] In an embodiment, the recycled cellulose and / or lignocellulose material comprises at least 80 % by weight of cellulose and / or lignocellulose material flakes 30, preferably at least 85 % by weight of cellulose and / or lignocellulose material flakes 30.

[0034] In an embodiment, the cellulose and / or lignocellulose material flakes 30 preferably have the average largest dimension selected within an interval of from 2 up to 20 mm. Accordingly, the average largest dimension of all the cellulose and / or lignocellulose material flakes 30 present in the recycled cellulose and / or lignocellulose material is selected within an interval of from 2 up to 20 mm.

[0035] In an embodiment, the recycled cellulose and / or lignocellulose material is or comprises recycled postindustrial and / or post-consumer cellulose and / or lignocellulose material comprising the cellulose and / or lignocellulose material flakes 30.

[0036] In this embodiment, recycled post-industrial and / or post-consumer cellulose and / or lignocellulose material can be used directly as recycled cellulose and / or lignocellulose material that is introduced into the forming head 110 in step S1 if that recycled post-industrial and / or post-consumer cellulose and / or lignocellulose material comprises cellulose and / or lignocellulose material flakes 30. Hence, no additional processing of the recycled post-industrial and / or post-consumer cellulose and / or lignocellulose material is required in this embodiment to obtain the recycled cellulose and / or lignocellulose material.

[0037] In this embodiment, the cellulose and / or lignocellulose material flakes 30 are thereby flakes 30 of the recycled post-industrial and / or post-consumer cellulose and / or lignocellulose material. The flakes 30 thereby comprise cellulose and / or lignocellulose but may also contain smaller amounts of other material, such as other components and / or additives, depending on the particular source or type of the recycled cellulose and / or lignocellulose material.

[0038] In other embodiments, the recycled post-industrial and / or post-consumer cellulose and / or lignocellulose material is processed to obtain the recycled cellulose and / or lignocellulose material. Such further embodiments will be described further with reference to Fig. 4.

[0039] Fig. 4 is a flow chart illustrating additional, optional steps of the method shown in Fig. 3 according to various embodiments. In an embodiment, the method comprises shredding, in step S10, recycled postindustrial and / or post-consumer cellulose and / or lignocellulose material to form shredded recycled postindustrial and / or post-consumer cellulose and / or lignocellulose material comprising cellulose and / or lignocellulose material flakes 30. The method then continues to step S12, which comprises milling the shredded recycled post-industrial and / or post-consumer cellulose and / or lignocellulose material to form the recycled cellulose and / or lignocellulose material comprising the cellulose and / or lignocellulose material flakes 30 having a surface roughness.

[0040] In this embodiment, post-industrial and / or post-consumer cellulose and / or lignocellulose material is used as the source of cellulose and / or lignocellulose. This means that recycled, reclaimed and / or re-used cellulose and / or lignocellulose material from paper- and / or board-making, -using or -converting processes or facilities and / or recycled cellulose and / or lignocellulose material from paper and / or board recycling streams is shredded to form the shredded post-industrial and / or post-consumer cellulose and / or lignocellulose material in step S10. The shredding in step S10 preferably shreds or chops the input postindustrial and / or post-consumer cellulose and / or lignocellulose material into cellulose and / or lignocellulose material flakes 30 that can then be further processed in a mill in step S12. The shredded recycled post-industrial and / or post-consumer cellulose and / or lignocellulose material as produced in step S10 is then milled in step S12 to form the recycled cellulose and / or lignocellulose material comprising the cellulose and / or lignocellulose material flakes 30 having the surface roughness.

[0041] In an embodiment, step S12 comprises disc milling the shredded recycled post-industrial and / or postconsumer cellulose and / or lignocellulose material to form the recycled cellulose and / or lignocellulose material comprising the cellulose and / or lignocellulose material flakes 30 having the surface roughness.

[0042] Disc milling is an illustrative, but preferred, embodiment of milling the shredded recycled post-industrial and / or post-consumer cellulose and / or lignocellulose material since such a disc milling roughens the surfaces of the cellulose and / or lignocellulose material flakes 30 to make the flakes 30 a bit scuffed and rugged. Disc mills, also referred to as disc refiners in the art, may be used to expose microfibrils on the surfaces of the cellulose and / or lignocellulose material flakes 30, thereby increasing their surface area and improving flake-to-flake bonding by the polymer binder. This has also the advantage of reducing the density of the cellulose and / or lignocellulose material flakes 30 and making the flakes 30 softer and more malleable, which promotes formation of a porous, open cell foam structure in the bonded air-laid blank 10 during the air-laying process. In addition, as mentioned above, the disc milling increases the surface area of the cellulose and / or lignocellulose material flakes 30, which promotes binding of the polymer binder to the cellulose and / or lignocellulose material flakes 30 during the heating step S3 in Fig. 3.

[0043] In the art, hammer milling has been extensively used to produce defibrated cellulose and / or lignocellulose material fibers for air-laying. Such a hammer milling achieves an efficient defibration of the pulp into individual, i.e., free, cellulose and / or lignocellulose material fibers. However, hammer milling has the disadvantage of also producing a significant amount of fines in the defibrated cellulose and / or lignocellulose fiber material.

[0044] In an embodiment, the method comprises an additional step S11 as shown in Fig. 4. This step S11 comprises selecting at least one operational parameter of a disc mill based on the type of recycled postindustrial and / or post-consumer cellulose and / or lignocellulose material and a target surface roughness of the cellulose and / or lignocellulose material flakes 30 and / or a target density of the recycled cellulose and / or lignocellulose material. The at least one operational parameter of the disc mill is preferably selected from the group consisting of a disc gap of the disc mill, rotational speed or speeds of the disc or discs of the disc mill and a flow-rate of an air-flow transporting the shredded recycled post-industrial and / or post-consumer cellulose and / or lignocellulose material into the disc mill. In such an embodiment, step S12 comprises disc milling the shredded recycled post-industrial and / or post-consumer cellulose and / or lignocellulose material with the disc mill operated according to the selected at least one operational parameter to form the recycled cellulose and / or lignocellulose material comprising the cellulose and / or lignocellulose material flakes 30. The cellulose and / or lignocellulose material flakes 30 in the obtained recycled cellulose and / or lignocellulose material thereby, by disc milling according to the selected operational parameter(s), have the target source roughness and / or the recycled cellulose and / or lignocellulose material has the target density.

[0045] Generally, the above-mentioned operational parameters of a disc mill, i.e., disc gap, rotational speed and flow rate, can be used to control the milling and surface processing of the recycled post-industrial and / or post-consumer cellulose and / or lignocellulose material. Generally, a smaller disc gap between the two discs of the disc mill increases the degree of milling of the recycled post-industrial and / or post-consumer cellulose and / or lignocellulose material and a larger disc gap reduces the degree of milling. Correspondingly, a higher rotational speed or speeds of the disc or discs increases the degree of milling of the recycled post-industrial and / or post-consumer cellulose and / or lignocellulose material and a lower rotational speed or speeds of the discs reduces the degree of milling. Further, a higher flow rate of the air-flow transporting the recycled post-industrial and / or post-consumer cellulose and / or lignocellulose material means that the recycled post-industrial and / or post-consumer cellulose and / or lignocellulose material is transported faster through the disc mill and thereby exposed to a shorter disc milling operation, i.e., shorter dwell time, as compared to when using a lower flow rate of the air-flow. The flow rate of the air-flow can thereby be used to control the dwell time and the degree of filling of the disc mill with the recycled post-industrial and / or post-consumer cellulose and / or lignocellulose material.

[0046] This means that one or more of these operational parameters of the disc mill can be used to control the disc milling performed in step S12 to make the cellulose and / or lignocellulose material flakes 30 in the recycled cellulose and / or lignocellulose material a bit scuffed and rugged, while also making the cellulose and / or lignocellulose material flakes 30 softer and more malleable. In an embodiment, step S11 comprises selecting one operational parameter, such as selecting the disc gap, selecting the rotation speed or selecting the flow rate. In another embodiment, step S11 comprises selecting two operational parameters, such as selecting the disc gap and the rotational speed, selecting the disc gap and the flow rate, or selecting the rotational speed and the flow rate. In a further embodiment, step S11 comprises selecting the three operational parameters, i.e., selecting the disc gap, the rotational speed and the flow rate. The at least one operational parameter of the disc mill is selected in step S11 based on the type of recycled post-industrial and / or post-consumer cellulose and / or lignocellulose material shredded in step S10 and further disc milled in step S12 in order to obtain the desired characteristics, i.e., density and / or surface roughness, of the cellulose and / or lignocellulose material flakes 30 present in the recycled cellulose and / or lignocellulose material.

[0047] For instance, the at least one operational parameter of the disc mill is preferably selected in step S11 depending on the particular recycled post-consumer cellulose and / or lignocellulose material, the particular recycled post-industrial cellulose and / or lignocellulose material or the particular mixture of recycled post-consumer and post-industrial cellulose and / or lignocellulose material used as input material to the shredding operation in step S10.

[0048] Various types of disc mills could be used in step S12 to disc mill the shredded recycled post-industrial and / or post-consumer cellulose and / or lignocellulose material. As an example, the disc mill could have one stationary disc and one rotating disc, two rotating discs, two stationary discs and one intermediate rotating disc or two stationary discs and two intermediate rotating discs as illustrative, but non-limiting, examples of disc mills. The discs may optionally be grooved, serrated, spiked or have some other types of surface structures to promote the grinding and milling operations of the disc mill.

[0049] The milling, preferably disc milling, in step S12 is preferably performed so that the recycled cellulose and / or lignocellulose material obtained in step S12 has a lower density than the shredded recycled postindustrial and / or post-consumer cellulose and / or lignocellulose material obtained in step S10. In an embodiment, the ratio of the density of the recycled cellulose and / or lignocellulose material following milling in step S12 and the density of the recycled post-industrial and / or post-consumer cellulose and / or lignocellulose material prior to milling in step S12 is smaller than 1, preferably smaller than 0.9, such as smaller than 0.8, more preferably smaller than 0.75, such as smaller than 0.7, smaller than 0.6 and most preferably smaller than 0.5. The ratio may also be smaller than 0.5, such as 0.45, 0.40 or even smaller. The density of the recycled cellulose and / or lignocellulose material following milling in step S12 and the recycled post-industrial and / or post-consumer cellulose and / or lignocellulose material prior to milling in step S12 can be measured or determined using any method for measuring density as long as the same method is used to measure or determine the density of the recycled cellulose and / or lignocellulose material following milling in step S12 as is used to measure or determine the density of the recycled postindustrial and / or post-consumer cellulose and / or lignocellulose material prior to milling in step S12. As an example, the (disc) milling of step S12 roughens the surfaces of the cellulose and / or lignocellulose material flakes 30 so that the surfaces become a bit scuffed and rugged to thereby obtain cellulose and / or lignocellulose material flakes 30 with "flurry” surfaces. Thus, surfaces of the cellulose and / or lignocellulose material flakes 30 are preferably rough surfaces. In other words, surfaces of the cellulose and / or lignocellulose material flakes 30 preferably comprise surface structures 35 as schematically shown in Fig. 2. These surface structures 35 are preferably in the form of short cellulose and / or lignocellulose material fibers or protrusions extending from the surfaces of the cellulose and / or lignocellulose material flakes 30. These cellulose and / or lignocellulose material fibers or protrusions thereby give the surfaces of the cellulose and / or lignocellulose material flakes 30 a fluffy texture or surface structure. Such surface structures 35, such as cellulose and / or lignocellulose material fibers or protrusions, promote binding of the polymer binder to the cellulose and / or lignocellulose material flakes 30 during the heating step S3 in Fig. 3. This means that the roughened surfaces of the cellulose and / or lignocellulose material flakes 30 as produced in the (disc) milling of step S12 facilitate an efficient bonding with the polymer binder even at low amounts of polymer binder in the bonded air-laid blank 10.

[0050] The shredding in step S10 chops the input recycled post-industrial and / or post-consumer cellulose and / or lignocellulose material into smaller cellulose and / or lignocellulose material flakes 30. The (disc) milling in step S12 mainly processes these cellulose and / or lignocellulose material flakes 30 by increasing the surface area of the cellulose and / or lignocellulose material flakes 30 and also by making the cellulose and / or lignocellulose material flakes 30 softer and more malleable. As a consequence, the (disc) milling generally reduces the density of the processed material so that the recycled cellulose and / or lignocellulose material obtained in step S12 typically has a lower density as compared to the recycled post- industrial and / or post-consumer cellulose and / or lignocellulose material input into the (disc) mill in step S12.

[0051] In the above-described embodiments, the recycled post-industrial and / or post-consumer cellulose and / or lignocellulose material is first shredded in step S10 and then the shredded recycled post-industrial and / or post-consumer cellulose and / or lignocellulose material is milled, preferably disc milled, in step S12 and preferably based on the at least one operational parameter as selected in step S11 .

[0052] In another embodiment, the shredding step S10 can be omitted. For instance, the recycled post-industrial and / or post-consumer cellulose and / or lignocellulose material could be in a form comprising a high quantity of cellulose and / or lignocellulose material flakes 30 with a suitable size distribution so that no shredding is required in order to chop the recycled post-industrial and / or post-consumer cellulose and / or lignocellulose material into cellulose and / or lignocellulose material flakes 30.

[0053] In such an embodiment, step S12 in Fig. 4 comprises milling, preferably disc milling, recycled postindustrial and / or post-consumer cellulose and / or lignocellulose material to form the recycled cellulose and / or lignocellulose material comprising the cellulose and / or lignocellulose material flakes 30 having a surface roughness.

[0054] In a particular embodiment, the method also comprises step S11. This step S11 comprises, in this particular embodiment, selecting at least one operational parameter of the disc mill based on the type of recycled post-industrial and / or post-consumer cellulose and / or lignocellulose material and a target surface roughness of the cellulose and / or lignocellulose material flakes 30 and / or a target density of the recycled cellulose and / or lignocellulose material. In such a particular embodiment, step S12 comprises disc milling the recycled post-industrial and / or post-consumer cellulose and / or lignocellulose material with the disc mill operated according to the selected at least one operational parameter to form the recycled cellulose and / or lignocellulose material comprising the cellulose and / or lignocellulose material flakes 30. The cellulose and / or lignocellulose material flakes 30 in the obtained recycled cellulose and / or lignocellulose material thereby, by disc milling according to the selected operational parameters), have the target source roughness and / or the recycled cellulose and / or lignocellulose material has the target density.

[0055] The cellulose and / or lignocellulose material flakes 30 of the recycled cellulose and / or lignocellulose material, such as produced as shown in Fig. 4, preferably have an average largest dimension selected within an interval of from 2 up to 20 mm. Fig. 2 schematically illustrates a cellulose and / or lignocellulose material flake 30. The cellulose and / or lignocellulose material flakes 30 could be of various forms from fairly round or elliptical, rectangular or quadratic to more irregular forms. Regardless of actual form or shape, the cellulose and / or lignocellulose material flakes 30 could be regarded as having three dimensions, schematically denoted length (L), width (W) and thickness (not shown) in Fig. 2. Two of the dimensions, typically the length and width, are most often larger than the remaining dimension, typically the thickness. In the illustrative example shown in Fig. 2, the largest dimension of the cellulose and / or lignocellulose material flake 30 is the length. In such an embodiment, the average length of the cellulose and / or lignocellulose material flakes 30 is preferably selected within an interval of from 2 up to 20 mm. The average values of the other dimensions of the cellulose and / or lignocellulose material flakes 30, such as the width and thickness, are then smaller than the average length of the cellulose and / or lignocellulose material flakes 30.

[0056] In a preferred embodiment, the average largest dimension of the cellulose and / or lignocellulose material flakes 30, such as length in Fig. 2, is preferably selected within an interval of from 5 to 15 mm.

[0057] In an embodiment, not only an average of the largest dimension, such as length in Fig. 2, but also an average of the next largest dimension, such as width in Fig. 2, is selected within an interval of from 2 to 20 mm, and preferably selected within an interval of from 5 up to 15 mm. In such an embodiment, the cellulose and / or lignocellulose material flakes 30 have an average largest dimension and an average next largest dimension independently selected within an interval of from 2 up to 20 mm, preferably selected within an interval of from 5 up to 15 mm. The average of the smallest dimension, such as thickness, of the cellulose and / or lignocellulose material flakes 30 is, however, typically smaller than 5 mm, such as smaller than 2 mm, or smaller than 1 mm. The average dimensions of the cellulose and / or lignocellulose material flakes 30 are preferably measured when the cellulose and / or lignocellulose material flakes 30 are extended or flattened, such as arranged between two opposite surfaces.

[0058] A recycled cellulose and / or lignocellulose material comprising cellulose and / or lignocellulose material flakes 30 with the above-described preferred dimensions is suitable for use in an air-laying process together with the defibrated pulp to produce a bonded air-laid blank 10. If the input recycled post-industrial and / or post-consumer cellulose and / or lignocellulose material is processed too much in steps S10 and S12 or in step S12 in order to produce a recycled cellulose and / or lignocellulose material comprising cellulose and / or lignocellulose material flakes 30 having the average largest dimension smaller than 2 mm, and in particular having the average largest dimension and the average next largest dimension both smaller than 2 mm, then the processing in steps S10 and S12 or step S12 will additionally produce a comparatively large amount of smaller cellulose and / or lignocellulose material particles. Such larger amounts of smaller cellulose and / or lignocellulose material particles would imply a larger risk for dusting and linting during and following the air-laying process if using less than 10 % by weight of the polymer binder. This means that a higher amount of polymer binder would be needed in the bonded air-laid blank 10 to capture all or at least the majority of such smaller cellulose and / or lignocellulose particles present in recycled cellulose and / or lignocellulose material comprising cellulose and / or lignocellulose material flakes 30 having the average largest dimension smaller than 2 mm. Further, a recycled cellulose and / or lignocellulose material comprising cellulose and / or lignocellulose material flakes 30 having the average largest dimension larger than 20 mm, and in particular having the average largest dimension and the average next largest dimension both larger than 20 mm, generally does not produce a bonded air-laid blank 10 with a porous, open cell foam structure. This means that such a bonded air-laid blank 10 will generally have inferior cushioning and insulation properties as compared to an air-laid blank 10 produced from the cellulose and / or lignocellulose material of the invention.

[0059] In an embodiment, the recycled post-consumer cellulose and / or lignocellulose material is cellulose and / or lignocellulose material recycled in one or more recycling streams, such as paper recycling stream and / or board recycling stream. Thus, in an embodiment, recycled post-consumer cellulose and / or lignocellulose material is selected from the group consisting of recycled paper, recycled printing paper, recycled newsprint, recycled paper board, recycled corrugated board, recycled cartonboard, recycled liner, recycled fluting, and any combination thereof.

[0060] In an embodiment, the recycled post-industrial cellulose and / or lignocellulose material is selected from the group consisting of chips, clips, clippings, waste, trim, trimmings, leftovers and / or scraps of, for instance, paper, printing paper, newsprint, paper board, corrugated board, cartonboard, liner and / or fluting, from a paper- and / or board-making, -using or -converting process or facility.

[0061] Thus, in an embodiment, the recycled post-industrial cellulose and / or lignocellulose material is selected from the group consisting of clips, clippings, waste, trim, trimmings, leftovers and / or scraps of recycled paper, recycled printing paper, recycled newsprint, recycled paper board, recycled corrugated board, recycled cartonboard, recycled liner, recycled fluting, and any combination thereof.

[0062] In an embodiment, the recycled cellulose and / or lignocellulose material is recycled post-consumer cellulose and / or lignocellulose material. In another embodiment, the recycled cellulose and / or lignocellulose material is recycled post-industrial cellulose and / or lignocellulose material. In a further embodiment, the recycled cellulose and / or lignocellulose material is a mixture of recycled post-consumer cellulose and / or lignocellulose material and recycled post-industrial cellulose and / or lignocellulose material. In an embodiment, the recycled post-industrial cellulose and / or lignocellulose material is or comprises Kraft liner material, such as clips, clippings, waste, trim, trimmings, leftovers and / or scraps of Kraft liner material.

[0063] In another embodiment, the recycled post-industrial cellulose and / or lignocellulose material is or comprises corrugated board, such as clips, clippings, waste, trim, trimmings, leftovers and / or scraps of corrugated board material.

[0064] In a further embodiment, the recycled post-consumer cellulose and / or lignocellulose material is or comprises recycled post-consumer corrugated board.

[0065] The recycled cellulose and / or lignocellulose material is preferably a recycled cellulose material. The recycled material, such as flakes 30, may, though, also contain lignin, such as in the form of lignocellulose. The recycled material may also be a mixture of cellulose material and lignocellulose material. Thus, lignocellulose as used herein refers to a mixture of cellulose and lignin.

[0066] In an embodiment, the defibrated pulp is defibrated virgin pulp. Virgin pulp is produced by chemically and / or mechanically separating cellulose and / or lignocellulose fibers from woods or fibre crops. This should be compared to recycled pulp, which is made of used paper, cardboard and other paper-based products that has been processed by chemicals to remove unwanted elements, such as ink, coatings, adhesives and other additives, and obtain recycled cellulose and / or lignocellulose fibers.

[0067] In an embodiment, the defibrated pulp is selected from the group consisting of defibrated sulfate pulp, defibrated sulfite pulp, defibrated thermomechanical pulp (TMP), defibrated high temperature thermomechanical pulp (HTMP), defibrated mechanical fiber intended for medium density fiberboard (MDF-fiber), defibrated chemi-thermomechanical pulp (CTMP), defibrated high temperature chemi- thermomechanical pulp (HTCTMP), and a combination thereof.

[0068] The defibrated pulp could be defibrated bleached pulp, defibrated unbleached pulp, or a combination of defibrated bleached and unbleached pulp.

[0069] In a preferred embodiment, the defibrated pulp is defibrated Kraft pulp and in particular defibrated unbleached Kraft pulp (UKP). The defibrated pulp comprises cellulose and / or lignocellulose fibers. The cellulose and / or lignocellulose fibers are preferably from a wood source, such as in the form of cellulose and / or lignocellulose pulp fibers produced by chemical, mechanical and / or chemi-mechanical pulping of softwood and / or hardwood. The cellulose and / or lignocellulose fibers may, however, be obtained by other pulping methods and / or from other cellulosic or lignocellulosic raw materials, such as flax, jute, hemp, kenaf, bagasse, cotton, bamboo, straw, or rice husk. It is also possible to use cellulose and / or lignocellulose fibers that are a mixture of fibers from different raw materials, such as a mixture of wood and any of the materials mentioned above.

[0070] In such an embodiment, the method may comprise an additional, optional step S13 as shown in Fig. 4. This step S13 comprises chemical, mechanical and / or chemi-mechanical pulping a cellulosic or lignocellulosic raw material, such as exemplified above and preferably wood, such as softwood and / or hardwood, to form the pulp, preferably virgin pulp.

[0071] Depending on the pulping process performed in step S13, the resulting pulp could be in the form of sulfate pulp, sulfite pulp, TMP, HTMP, MDF-fiber, CTMP, or HTCTMP.

[0072] The defibrated pulp is then produced by defibrating the pulp, preferably virgin pulp as obtained in step S13 in a following step S14. The defibration in step S14 can be performed according to any method that defibrates pulp by separating the fibrous cellulose and / or lignocellulose material obtained in the pulping process in step S13 into individual cellulose and / or lignocellulose fibers. Illustrative, but non-limiting, examples of such defibrating methods include hammer mills, refiners, disc mills, etc.

[0073] In an embodiment, the defibration method used in step S14 preferably generates the desired cellulose and / or lignocellulose fibers but produces a low amount of smaller cellulose and / or lignocellulose particles, such as fiber fragments, debris, i.e., fines. This trade-off between producing individual cellulose and / or lignocellulose fibers while reducing the amount of smaller cellulose and / or lignocellulose particles can also be controlled by the defibration degree of the defibration in step S14. Thus, heavily defibrating pulp, i.e., a high defibration degree, effectively separates the pulp into individual cellulose and / or lignocellulose fibers but typically also generates a comparatively high amount of smaller cellulose and / or lignocellulose particles. Correspondingly, mild defibration, i.e., a low defibration degree, generally results in lower amounts of smaller cellulose and / or lignocellulose particles but part of the cellulose and / or lignocellulose fiber material is in the form of knots. Such mild defibration means that the defibrated pulp contains a mixture of fully defibrated cellulose and / or lignocellulose fibers and non-defibrated cellulose and / or lignocellulose fibers, i.e., cellulose and / or lignocellulose fiber aggregates or knots, also referred to as nits, nodules, bundles, non-defibrated pulp in the art. These knots thereby maintain the cellulose and / or lignocellulose fibers together in aggregates, such as by maintaining hydrogen bonds between cellulose and / or lignocellulose fibers.

[0074] Defibrated pulp as used herein encompasses pulp that is heavily, such as fully, defibrated in step S14 to mainly contain fully defibrated cellulose and / or lignocellulose fibers. Defibrated pulp also encompasses pulp that is mildly defibrated, also referred to as partly defibrated, in step S14 to contain a mixture of defibrated cellulose and / or lignocellulose fibers and knots.

[0075] In an embodiment, the defibrated pulp is so-called partly defibrated pulp that comprises defibrated, i.e., free or individual, cellulose and / or lignocellulose fibers and knots. Such defibrated pulp preferably has a knots content of at least 5 % by weight, preferably at least 10 % by weight, more preferably at least 15 % by weight and most preferably at least 20 % by weight.

[0076] In an embodiment, the knots content of the partly defibrated pulp is determined by air-jet sieving with a sieve size of 1400 pm (14 mesh, American Society for Testing and Materials (ASTM) no. 14), a sieving pressure of 4000 Pa and a sieving time of 10 min.

[0077] Air-jet sieving is a standard operating procedure for particle size analysis and in particular analysis of the knots content of pulp.

[0078] An example of an air-jet sieving apparatus, also referred to as air-jet sieve in the art, that could be used to determine the knots content is Air Jet Sieve e200 LS by Hosokawa Alpine. In such a sieving operation, the 14 mesh sieve is inserted in the air-jet sieve, the defibrated pulp to analyze is spread on the sieve and the air-jet sieve is set to manual sieving with a sieving pressure of 4000 Pa and a sieving duration of 10 min. When the sieving is finished the knots remain on the sieve. The knot content can then be calculated as: 100 wherein represents the initial weight of the defibrated pulp and w2represents the amount of remaining knots after sieving. The defibrated pulp may also comprise cellulose and / or lignocellulose fibers in the form of shives. A shive is a small bundle of incompletely cooked fibers in the pulping process.

[0079] In an embodiment, the cellulose and / or lignocellulose fibers of the defibrated pulp have a length weighted average fiber length of up to 10 mm, preferably of up to 8 mm, more preferably of up to 6 mm, and most preferably of up to 5 mm. In a particular embodiment, the cellulose and / or lignocellulose fibers of the defibrated pulp have a length weighted average fiber length selected within an interval of from 1 mm up to 10 mm, preferably selected within an interval of from 1 mm up to 8 mm, more preferably selected within an interval of from 1 mm up to 6 mm, and most preferably selected within an interval of from 1 mm up to 5 mm.

[0080] Length of fibers, such as cellulose and / or lignocellulose fibers, as referred to herein is length weighted average fiber length. Length weighted average fiber length is calculated as the sum of individual fiber lengths squared divided by the sum of the individual fiber lengths as described in e.g., IS0 16065-1 :2014, Pulps - Determination of fibre length by automated optical analysis- Part 1 : Polarized light method, or ISO 16065-2:2014, Pulps - Determination of fibre length by automated optical analysis - Part 2: Unpolarized light method.

[0081] The defibrated pulp comprises the cellulose and / or lignocellulose fibers as a main cellulose and / or lignocellulose component. The defibrated pulp may also comprise some smaller quantities of fiber fragments and smaller cellulose and / or lignocellulose particles, such as fines. The cellulose and / or lignocellulose fibers in the defibrated pulp may be in the form of individual fibers but also fiber aggregates, such as knots and / or shives.

[0082] In an embodiment, the defibrated pulp comprises no more than 25 % by weight, preferably no more than 20 % by weight and more preferably no more than 15 % by weight, of fiber fragments and smaller cellulose and / or lignocellulose particles, such as fines.

[0083] In an embodiment, cellulose and / or lignocellulose material comprises the recycled cellulose and / or lignocellulose material as a main cellulose and / or lignocellulose material and the defibrated pulp as a minor cellulose and / or lignocellulose material. Hence, in an embodiment, the percentage by weight of the recycled cellulose and / or lignocellulose material is higher than the percentage by weight of the defibrated pulp in the cellulose and / or lignocellulose material. In such an embodiment, the recycled cellulose and / or lignocellulose material constitutes the main bulk of the produced bonded air-laid blank 10. The defibrated pulp is then preferably included to enhance the open cell foam structure and porosity of the bonded airlaid blank 10 and thereby the cushioning and / or insulation capacity of the bonded air-laid blank 10 and products produced therefrom. Thus, the cellulose and / or lignocellulose fibers in the defibrated pulp promote formation of a porous structure in the bonded air-laid blank 10 having an open cell foam character. Such a porous structure enhances the insulation and cushioning characteristics of the bonded air-laid blank 10.

[0084] The amount of defibrated pulp included in the cellulose and / or lignocellulose material can thereby be selected or tailored based on the type of recycled cellulose and / or lignocellulose material used as main constituent of the cellulose and / or lignocellulose material in order to achieve a desired cushioning and / or insulation capacity of the bonded air-laid blank 10.

[0085] In an embodiment, the cellulose and / or lignocellulose material consists of the recycled cellulose and / or lignocellulose material and the defibrated pulp.

[0086] In an embodiment, the cellulose and / or lignocellulose material comprises the defibrated pulp at an amount selected within an interval of from 2.5 up to 20 % by weight. In a preferred embodiment, the cellulose and / or lignocellulose material comprises the defibrated pulp at an amount selected within an interval of from 5 up to 15 % by weight.

[0087] In an embodiment, the cellulose and / or lignocellulose material comprises the recycled cellulose and / or lignocellulose material at an amount selected within an interval of from 80 up to 97.5 % by weight. In a preferred embodiment, the cellulose and / or lignocellulose material comprises the recycled cellulose and / or lignocellulose material at an amount selected within an interval of from 85 up to 95 % by weight.

[0088] In an embodiment, the cellulose and / or lignocellulose material comprises, preferably consists of, the defibrated pulp at an amount selected within an interval of from 2.5 up to 20 % and the recycled cellulose and / or lignocellulose material at an amount selected within an interval of from 80 up to 97.5 % by weight. In a preferred embodiment, the cellulose and / or lignocellulose material comprises, preferably consists of, the defibrated pulp at an amount selected within an interval of from 5 up to 15 % and the recycled cellulose and / or lignocellulose material at an amount selected within an interval of from 85 up to 95 % by weight.

[0089] In an embodiment, the method comprises mixing the recycled cellulose and / or lignocellulose material, the defibrated pulp and the polymer binder in one or more mixing operations as represented by step S15 in Fig. 4. Such a mixing could involve mixing all three main components in one mixing operation or performing multiple, i.e., at least two, successive mixing operations. As an example, the recycled cellulose and / or lignocellulose material, the defibrated pulp and the polymer binder can be mixed together in a single mixing operation in step S15. In another example, the recycled cellulose and / or lignocellulose material and the defibrated pulp are first mixed together in step S15 and then the polymer binder is added to this mixture in a second mixing operation in step S15. In a further example, the recycled cellulose and / or lignocellulose material and the polymer binder are first mixed together in step S15 and then the defibrated pulp is added to this mixture in a second mixing operation in step S15. In yet another example, the defibrated pulp and the polymer binder are first mixed together in step S15 and then the recycled cellulose and / or lignocellulose material is added to this mixture in a second mixing operation in step S15. A further example is to mix the recycled cellulose and / or lignocellulose material and a first part of the polymer binder to form a first mixture and mix the defibrated pulp and a second, such as remaining, part of the polymer binder to form a second mixture in step S15. In this example, the first and second mixtures are then mixed together in step S15.

[0090] The method optionally, but preferably continues from step S15 in Fig. 4 to a next step S16. Step S16 comprises transporting the mixture of the recycled cellulose and / or lignocellulose material, the defibrated pulp and the polymer binder by an air flow in a conduit 170 to the forming head 110. The method then continues to step S1 in Fig. 3. Hence, in a preferred embodiment, the recycled cellulose and / or lignocellulose material, the defibrated pulp and the polymer binder are preferably introduced into the forming head 1 10 in the form of a mixture as transported by an air flow in a conduit 170 in fluid connection with an inlet 111 of the forming head 1 10.

[0091] In an embodiment, the system 100 for producing a bonded air-laid blank 10 as shown in Fig. 5 comprises a single conduit 170 arranged to convey the air flow of the mixture of the recycled cellulose and / or lignocellulose material, the defibrated pulp and the polymer binder into the inlet 111 of the forming head 110. In another embodiment, the system 100 comprises multiple conduits 170 arranged to convey the air flow of the mixture of the recycled cellulose and / or lignocellulose material, the defibrated pulp and the polymer binder into separate inlets 111 of the forming head 1 10. In a further embodiment, the system 100 comprises at least one conduit 170 arranged to convey an air flow of the recycled cellulose and / or lignocellulose material, at least one conduit arranged to convey an air flow of the defibrated pulp and at least one conduit arranged to convey an air flow of the polymer binder. In this embodiment, the mixing of the recycled cellulose and / or lignocellulose material, the defibrated pulp and the polymer binder is taking place first within the forming head 110. In yet another embodiment, the system comprises at least one conduit 170 arranged to convey an air flow of a mixture of two of the recycled cellulose and / or lignocellulose material, the defibrated pulp and the polymer binder, and at least one conduit 170 arranged to convey an air flow of the remaining one of the recycled cellulose and / or lignocellulose material, the defibrated pulp and the polymer binder.

[0092] The conduit 170 in Fig. 5 is illustrated as a vertical conduit 170 connected to the forming head 110. The embodiments are, however, not limited thereto. The conduit 170 could be a horizontal conduit connected to the forming head 110 or being angled with an angle from 0° (vertical conduit) up to 90° (horizontal conduit) relative to the forming head 110. In these various embodiments, the air flow flowing through the conduit 170 will incident into the forming head 1 10 with an angle of incidence from 0° (vertical conduit) up to 90° (horizontal conduit). The conduit 170 can also comprise multiple conduit sections separated by a turn. As an example, an upstream section of the conduit 170 could be an upstream vertical conduit section, which is followed by a turn and then a downstream horizontal conduit section that is in fluid communication with the inlet 111 of the forming head 110. Another example is a conduit 170 with an upstream horizontal section followed by a turn and then a downstream vertical conduit section.

[0093] The recycled cellulose and / or lignocellulose material, the defibrated pulp and the polymer binder are introduced in step S1 of Fig. 3 into the forming head 110, also referred to as forming chamber in the art, as discrete input streams and / or as one or more mixed input streams at one or more inlets 111. The recycled cellulose and / or lignocellulose material, the defibrated pulp and the polymer binder are mixed and blended during the passage through the forming head 110 ultimately forming an unbonded air-laid web 20 on the conveyor 120. The forming head 110 may include equipment arranged inside the forming head 110 to promote separation and mixing of the recycled cellulose and / or lignocellulose material, the defibrated pulp and the polymer binder during the passage through the forming head 110. Such equipment may comprise, for instance, rolls with interlocking spikes, one or more drums, such as slit drums, and / or one or more strainers.

[0094] The recycled cellulose and / or lignocellulose material, the defibrated pulp and the polymer binder or the mixture thereof pass(es) through the forming head 110 to the outlet 113, such as arranged in connection with a lower end 114 of the forming head 110 and is further mixed through this passage. The mixture of the recycled cellulose and / or lignocellulose material, the defibrated pulp and the polymer binder is then captured on the conveyor 120. In an embodiment, the conveyor 120 is an air-permeable conveyor 120 and the mixture of the recycled cellulose and / or lignocellulose material, the defibrated pulp and the polymer binder is captured at least partly by a vacuum, i.e., an air suction or under-pressure, applied across the air-permeable conveyor 120 that is disposed in connection with the outlet 113 of the forming head 110. Hence, in an embodiment, the method of Fig. 3 preferably comprises an additional step of passing the mixture of the recycled cellulose and / or lignocellulose material, the defibrated pulp and the polymer binder to the outlet 1 13 of the forming head 110 while applying a gas suction through the air- permeable conveyor 120 in connection with the outlet 113 of the forming head 110.

[0095] Such a gas suction or vacuum is applied through the air-permeable conveyor 120. The gas suction or vacuum applied across the air-permeable conveyor 120, thus, draws the mixture of the recycled cellulose and / or lignocellulose material, the defibrated pulp and the polymer binder down onto the air-permeable conveyor 120. For instance, the air-permeable conveyor 120 could comprise a plurality of openings, through holes or channels allowing air to be sucked or drawn through the air-permeable conveyor 120. As an illustrative, but non-limiting, example, the air-permeable conveyor 120 could be a mesh conveyor, a wire conveyor or a belt conveyor with a belt comprising a plurality of minute through holes. However, any such openings are preferably small enough to prevent the cellulose and / or lignocellulose material and the polymer binder from passing through the air-permeable conveyor 120. Hence, the recycled cellulose and / or lignocellulose material, the defibrated pulp and the polymer binder are instead deposited as a mixture onto the air-permeable conveyor 120 in the form of an unbonded air-laid web 20.

[0096] In an embodiment, the conveyor 120 is an endless air-permeable conveyor. As an example, the conveyor 120 could comprise an endless conveyor belt 122 running along driver rollers 124, 126 as shown in Fig. 5. An endless conveyor belt 122 is a conveyor belt 122 that has been made into an endless belt 122 without joints. Such an endless conveyor belt 122 is also referred to as jointless conveyor belt in the art.

[0097] In an embodiment, step S3 comprises heat treating the unbonded air-laid web 20 to at least partly melt, i.e., tackify, the polymer binder and form the bonded air-laid blank 10. The heat treatment applied in step S3 performs a bonding operation, in which the unbonded air-laid web 20 is introduced into or otherwise passes a heating device 140, also referred to as a bonding oven or heater, see Fig. 5, where heat, such as in the form of heated or hot air, is blown into, sucked into and / or circulated through the unbonded airlaid web 20 to melt or partially melt the polymer binder. The polymer binder thereby becomes tacky and adheres to the recycled cellulose and / or lignocellulose material and the defibrated pulp and, thus, holds the recycled cellulose and / or lignocellulose material and the pulp fibers together and thereby results in a bonded air-laid blank 10. In a particular embodiment, the heating device 140 is arranged to heat the unbonded air-laid web 20 to a temperature selected within an interval of from 100°C up to 210°C, preferably within an interval of from 100°C up to 190°C, and more preferably within an interval of from 100°C up to 165°C. A too high temperature may damage and deteriorate the recycled cellulose and / or lignocellulose material and / or the defibrated pulp in the unbonded air-laid web 20.

[0098] The heating or bonding operation in step S3 may also comprise, and / or be accompanied by, a densification to create a larger number of binding points in the cellulose and / or lignocellulose material and, thus, a stronger and denser bonded air-laid blank 10. Such a densification operation could be applied either before the bonded air-laid blank 10 has been allowed to cool after the heating device 140 or upon renewed heating, such as in a heated calender. It is also possible to perform the densification operation in the heating device 140, e.g., as a combined heating and densification operation. In this latter case, step S3 comprises heat treating the unbonded air-laid web 20 to at least partly melt the polymer binder and simultaneously applying pressure onto the unbonded air-laid web 20 to form the bonded air-laid blank 10. The densification can include various types of operations including, but not limited to, calendering and / or pressing operations.

[0099] In an embodiment, the method also comprises cooling the bonded air-laid blank 10 by blowing a gas or gas mixture through the bonded air-laid blank 10.

[0100] In this embodiment, the system 100 comprises a cooling device 150 arranged downstream of the heating device 140. Such a cooling device 150 is then arranged to blow a gas or a gas mixture, typically air, through the bonded air-laid blank 10 to cool the bonded air-laid blank 10 as output from the heating device 140. The cooling device 150 could then cool the air-laid blank 10 to a temperature at or slightly above ambient temperature or to a temperature above ambient temperature but below the temperature inside the heating device 140, such as to a temperature at which the polymer binder solidifies sufficiently.

[0101] In an embodiment, the method also comprises cutting the bonded air-laid blank 10 following heating in step S3 in Fig. 3 or the optional cooling step. The cutting operation could be performed using any suitable cutter or cutting device 160. Illustrative, but non-limiting examples, of such cutting device 160 include a saw, a punch, a knife, etc. The cutting device 160 is preferably in the form of a cross-cutting device 160 that cuts through the whole thickness of the bonded air-laid blank 10. The cutting step divides the (continuous) bonded air-laid blank 10 into suitable sizes for downstream handling and processing, see Fig. 1. The cutting could be across the width of the bonded air-laid blank 10 to get, for instance, rectangular or quadratic bonded air-laid blank pieces.

[0102] The cutting is preferably performed while the bonded air-laid blank 10 is transported on the conveyor 120. Hence, it is generally preferred if the cutting device 160 is moved in synchrony with the bonded airlaid blank 10 during the cutting step. For instance, the cutting device 160 is starting the cutting from a start position and then moves in synchrony with the bonded air-laid blank 10 in the longitudinal direction of the bonded air-laid blank 10 until the cutting is completed at a stop position. The cutting device 160 is then preferably transported back to the start position to be ready for a next cutting operation.

[0103] As shown in Fig. 5, the conveyor 120 could include bend rollers 121 and at least one take-up roller 123 arranged to divert the conveyor belt 122 away from the cutting device 160. This means that the conveyor belt 122 turns away from the cutting device 160 to enable the cutting device 160 to cut through the complete thickness of the bonded air-laid blank 10 without the risk of engaging and damaging the conveyor belt 122. The bend rollers 121 could be in the form of bend pulleys or bend idlers and the takeup roller(s) 123 could be in the form of take-up pulley (s) or take-up idler(s).

[0104] In an embodiment, the cutting device 160 and the bend rollers 121 and take-up roller(s) 123 are preferably movable relative to the conveyor 120 to be moved, preferably in synchrony, with the bonded air-laid blank 10 transported by the conveyor 120. This is schematically illustrated by the hatched arrow in Fig. 5.

[0105] Another aspect of the invention relates to a bonded air-laid blank 10 comprising at least 80 % by weight of a cellulose and / or lignocellulose material comprising a recycled cellulose and / or lignocellulose material and defibrated pulp, and less than 10 % by weight of a polymer binder binding together the cellulose and / or lignocellulose material and the defibrated pulp.

[0106] In an embodiment, the recycled cellulose and / or lignocellulose material comprises cellulose and / or lignocellulose flakes 30.

[0107] In an embodiment, the recycled cellulose and / or lignocellulose material comprises at least 75 % by weight of cellulose and / or lignocellulose material flakes 30, preferably at least 80 % by weight, and more preferably at least 85 % by weight of cellulose and / or lignocellulose material flakes 30. Thus, the recycled cellulose and / or lignocellulose material preferably mainly comprises cellulose and / or lignocellulose material in the form of cellulose and / or lignocellulose material flakes 30 but may also contain some minor part(s) of cellulose and / or lignocellulose fibers, or fiber fragments and smaller particles, such as fines.

[0108] In an embodiment, the recycled cellulose and / or lignocellulose material comprises, such as consists of, at least 75 % by weight of cellulose and / or lignocellulose material flakes 30, and less than 25 % by weight of cellulose and / or lignocellulose material particles, such as cellulose and / or lignocellulose fibers, or fiber fragments and smaller particles, such as fines.

[0109] The cellulose and / or lignocellulose material particles then have an average largest dimension that is smaller or shorter than the average largest dimension of the cellulose and / or lignocellulose flakes 30.

[0110] In an embodiment, the recycled cellulose and / or lignocellulose material comprises recycled postindustrial and / or post-consumer cellulose and / or lignocellulose material comprising cellulose and / or lignocellulose material flakes 30.

[0111] In another embodiment, the recycled cellulose and / or lignocellulose material comprises milled, preferably disc milled, recycled post-industrial and / or post-consumer cellulose and / or lignocellulose material comprising cellulose and / or lignocellulose material flakes 30 having a surface roughness.

[0112] In a further embodiment, the recycled cellulose and / or lignocellulose material comprises shredded and milled, preferably disc milled, recycled post-industrial and / or post-consumer cellulose and / or lignocellulose material comprising cellulose and / or lignocellulose material flakes 30 having a surface roughness.

[0113] In a particular embodiment, the recycled cellulose and / or lignocellulose material only or substantially only comprises the cellulose and / or lignocellulose material flakes 30, and preferably such flakes 30 having an average largest dimension selected within an interval of from 2 up to 20 mm, and cellulose and / or lignocellulose material particles having an average largest dimension that is smaller or shorter than the average largest dimension of the cellulose and / or lignocellulose material flakes 30. Thus, in an embodiment, the cellulose and / or lignocellulose material flakes 30 having the average largest dimension selected within an interval of from 2 up to 20 mm, and cellulose and / or lignocellulose material particles having an average largest dimension that is smaller or shorter than the average largest dimension of the cellulose and / or lignocellulose material flakes 30 together constitute at least 90 % by weight, preferably at least 95 % by weight, more preferably at least 97 % by weight, and most preferably at least 98 % by weight or at least 99 % by weight, or indeed 100 % by weight of the recycled cellulose and / or lignocellulose material.

[0114] In a particular embodiment, the recycled cellulose and / or lignocellulose material comprises at least X % by weight of cellulose and / or lignocellulose material flakes 30, preferably having the average largest dimension selected within an interval of from 2 up to 20 mm, and less than (100-X) % by weight of cellulose and / or lignocellulose material particles, preferably having an average largest dimension that is smaller or shorter than the average largest dimension of the cellulose and / or lignocellulose material flakes 30. X is then a positive integer equal to or larger than 75 but equal to or smaller, preferably smaller than 100. The cellulose and / or lignocellulose material particles comprise cellulose and / or lignocellulose material fibers, cellulose and / or lignocellulose material fiber fragments, and / or cellulose and / or lignocellulose material fines.

[0115] In an embodiment, the bonded air-laid blank 10 comprises at least 80 % by weight of the cellulose and / or lignocellulose material. In a preferred embodiment, the bonded air-laid blank 10 comprises at least 90 % by weight, preferably at least 92.5 % by weight, more preferably at least 95 % by weight, and most preferably at least 97.5 % by weight, of the cellulose and / or lignocellulose material.

[0116] In an embodiment, the bonded air-laid blank 10 comprises the polymer binder at a concentration selected within an interval of from 0.1 up to but not including 10 % by weight, preferably selected within an interval of from 0.1 up to 7.5 % by weight. In a preferred embodiment, the bonded air-laid blank 10 comprises the polymer binder at a concentration selected within an interval of from 0.5 up to 5 % by weight, preferably selected within an interval of from 0.5 up to 2.5 % by weight, or more preferably selected within an interval of from 1 up to 5 % by weight, such as selected within an interval of from 1 up to 3 % by weight.

[0117] Percentage by weight (% by weight) as used herein is preferably determined using standard atmosphere for testing pulp, paper and board as defined in ISO 187:2022 Paper, board and pulps — Standard atmosphere for conditioning and testing and procedure for monitoring the atmosphere and conditioning of samples, i.e., temperature 23 ± 1 °C and relative humidity (RH) 50 ± 2 %.

[0118] Reference to an interval of from X up to Y herein includes the range of values between X and Y including the end points of the interval, i.e., X and Y. The polymer binder is included to bind the bonded air-laid blank 10 together and preserve its form and structure during use, handling, and storage. In an embodiment, the polymer binder may also assist in building up the foam-like structure of the bonded air-laid blank 10. The polymer binder is, in such an embodiment, intermingled with the cellulose and / or lignocellulose material during the air-laying process forming a mixture. The polymer binder may be added in the form of a powder but is more often added in the form of fibers that are intermingled with the cellulose and / or lignocellulose material in the air-laying process.

[0119] In a particular embodiment, the polymer binder is selected from the group consisting of a polymer powder, polymer fibers and a combination thereof.

[0120] The polymer binder could be a natural or synthetic polymer binder, or a mixture of natural polymer binders, a mixture of synthetic polymer binders, or a mixture of natural and synthetic polymer binders, but is preferably a thermoplastic polymer binder.

[0121] In an embodiment, the polymer binder is selected from the group consisting of a thermoplastic polymer powder, thermoplastic polymer fibers, and a combination thereof. In a preferred embodiment, the polymer binder is in the form of thermoplastic polymer fibers.

[0122] In an embodiment, the polymer binder is made from i) a material selected from the group consisting of polyvinyl alcohol (PVOH), thermoplastic starch (TPS), polyethylene (PE), ethylene acrylic acid copolymer (EAA), ethylene-vinyl acetate (EVA), polypropylene (PP), polystyrene (PS), such as styrene-butadiene rubber (SBR) or styrene acrylate copolymer, polybutylene adipate terephthalate (PBAT), polybutylene succinate (PBS), polylactic acid (PLA), polyethylene terephthalate (PET), polycaprolactone (PCL), polyvinyl alcohol (PVA), polyethylene glycol (PEG), poly (2-ethyl-2-oxazoline) (PEOX), polyvinyl ether (PVE), polyvinylpyrrolidone (PVP), polyacrylic acid (PAA), polymethacrylic acid (PMAA), polyvinyl acetate (PVAc), polyurethane (PU), copolymers thereof and mixtures thereof, and II) optionally one or more additives.

[0123] Hence, in an embodiment, the polymer binder is made of a material selected from the above-mentioned group. In another embodiment, the polymer binder is made of a material selected from the above- mentioned group and one or more additives. In an embodiment, the polymer binder is or comprises, such as consists of, mono-component and / or bicomponent polymer fibers. Bi-component polymer fibers, also known as bico fibers, comprise a first polymer, copolymer and / or polymer mixture and a second, different polymer, copolymer and / or polymer mixture. Most often the bi-component polymer fiber comprises a core made of the first polymer, copolymer and / or polymer mixture and a sheath made of the second polymer, copolymer and / or polymer mixture, although other combinations of two or even more polymers, copolymers and / or polymer mixtures are possible.

[0124] In an embodiment, the polymer binder is a thermoplastic polymer binder and the thermoplastic polymer binder is or comprises, such as consists of, mono-component thermoplastic polymer fibers made of i) a material selected from the group consisting of PVOH, TPS, PE, EAA, EVA, PP, PS, PBAT, PBS, PLA, PET, PCL, PVA, PEG, PEOX, PVE, PVP, PAA, PMAA, PVAc, PU, copolymers thereof and mixtures thereof, and ii) optionally one or more additives. In another particular embodiment, the thermoplastic polymer binder is or comprises, such as consists of, bi-component thermoplastic polymer fibers having a first material, such as a core made of i) a first material, selected from the group consisting of PVOH, TPS, PE, EAA, EVA, PP, PS, PBAT, PBS, PLA, PET, PCL, PVA, PEG, PEOX, PVE, PVP, PAA, PMAA, PVAc, PU, copolymers thereof and mixtures thereof, and ii) optionally one or more additives, and a second material, such as a sheath made of i) a second material, typically a different material, selected from the group consisting of TPS, PE, EAA, EVA, PP, PS, PBAT, PBS, PLA, PET, PCL, PVA, PEG, PEOX, PVE, PVP, PAA, PMAA, PVAc, PU, copolymers thereof and mixtures thereof, and ii) optionally one or more additives. In a further embodiment, the thermoplastic polymer binder is or comprises, such as consists of, a combination or mixture of mono-component thermoplastic polymer fibers made of i) a material selected from the group consisting of PVOH, TPS, PE, EAA, EVA, PP, PS, PBAT, PBS, PLA, PET, PCL, PVA, PEG, PEOX, PVE, PVP, PAA, PMAA, PVAc, PU, copolymers thereof and mixtures thereof, and ii) optionally one or more additives, and bi-component thermoplastic polymer fibers having i) materials, such as of the core and / or sheath, selected from the group consisting of PVOH, TPS, PE, EAA, EVA, PP, PS, PBAT, PBS, PLA, PET, PCL, PVA, PEG, PEOX, PVE, PVP, PAA, PMAA, PVAc, PU, copolymers thereof and mixtures thereof, and ii) optionally one or more additives.

[0125] The thermoplastic polymer binder could be made of a single type of thermoplastic polymer fibers, i.e., made of a same material in the case of mono-component thermoplastic polymer fibers or made of the same materials in the case of bi-component thermoplastic polymer fibers. However, it is also possible to use a thermoplastic polymer binder made of one or multiple, i.e., two or more, different mono-component thermoplastic polymer fibers made of different materials and / or one or multiple different bi-component thermoplastic polymer fibers made of different materials.

[0126] An advantage of using bi-component thermoplastic polymer fibers is that they can have a core with a higher melting point that keeps its fiber form during the binding operation, whereas the sheath melts and becomes tacky. The intact core will support the three-dimensional structure of the bonded air-laid blank 10 and, thus, promote porosity while the melted or tackified sheath will attach to the recycled cellulose and / or lignocellulose material and preserve the strength of the bonded air-laid blank 10.

[0127] In an embodiment, the polymer binder is a polymer powder, preferably a thermoplastic polymer powder, made of I) a material selected from the group consisting of PVOH, TPS, PE, EAA, EVA, PP, PS, PBAT, PBS, PLA, PET, PCL, PVA, PEG, PEOX, PVE, PVP, PAA, PMAA, PVAc, PU, copolymers thereof and mixtures thereof, and II) optionally one or more additives.

[0128] It is also, as mentioned in the foregoing, possible to use a thermoplastic polymer binder that is a combination of thermoplastic polymer fibers and thermoplastic polymer powder.

[0129] In an embodiment, the polymer binder comprises or is in the form of polymer binder fibers, such as thermoplastic polymer fibers. In such an embodiment, the polymer fibers preferably have an average length of less than 17.5 mm. Too long polymer binder fibers, i.e., above 17.5 mm, will not efficiently intermingle within the recycled cellulose and / or lignocellulose material comprising cellulose and / or lignocellulose material flakes 30 during the air-laying process. In more detail, long polymer binder fibers will mainly extend in parallel planes in the unbonded air-laid web 20 when captured on the conveyor 120. Thus, the long length of the polymer binder fibers means that they mainly orientate in planes in the unbonded air-laid web 20, such as along planes in the length and width direction as shown in Fig. 1 , or slightly angled relative the length and width direction. The long polymer binder fibers, however, have difficulties in orienting along the thickness direction of the unbonded air-laid web 20. This will have the effect that bonded air-laid blanks 10 produced from a mixture of defibrated pulp and recycled cellulose and / or lignocellulose material and polymer binder fibers having an average length above 17.5 mm tend to form a layered structure. The cellulose and / or lignocellulose material within one layer is efficiently bond by the polymer binder fibers but, due to few polymer binder fibers oriented along the thickness direction of the bonded air-laid blanks 10, there is less efficient bonding between such layers. There is therefore a risk that bonded air-laid blanks 10 and products produced therefrom will, during handling and use, fall apart due to inefficient bonding in all directions within the bonded air-laid blanks 10. In an embodiment, the polymer binder fibers have an average length of less, i.e., smaller or shorter, than 15 mm, preferably less than 12.5 mm and more preferably less than 10 mm.

[0130] In an embodiment, the polymer binder fibers are cut polymer binder fibers, sometimes referred to as staple fibers. In such an embodiment, each polymer binder fiber has a respective cut length or staple length. In such an embodiment, the average length as referred to in the foregoing is the average cut length or average staple length of the polymer binder fibers.

[0131] The bonded air-laid blank 10 may comprise one or more additives in addition to the cellulose and / or lignocellulose material and the polymer binder. One or more additives could be added to the polymer binder and / or added when producing the polymer binder. Alternatively, or in addition, one or more additives could be added to the recycled cellulose and / or lignocellulose material and / or the defibrated pulp. Alternatively, or in addition, one or more additives could be added to the mixture of the recycled cellulose and / or lignocellulose material, the defibrated pulp and the polymer binder, such as during the air-laying process or prior to the air-laying process.

[0132] Illustrative, but non-limiting, examples of such additives include electrically conducting or semiconducting fillers, coupling agents, flame retardants, dyes, impact modifiers, hydrophobization agents, etc.

[0133] The bonded air-laid blank 10 produced according to the invention has preferably an average thickness W, see Fig. 1 , of at least 5 mm, and preferably an average thickness of at least 5 mm and at most 200 mm.

[0134] In an embodiment, the bonded air-laid blank 10 has an average density selected within an interval of from 10 up to 200 kg / m3, such as from 18 up to 190 kg / m3.

[0135] In an embodiment, the bonded air-laid blank 10 has an average grammage selected within an interval of from 300 up to 10000 g / m2.

[0136] The bonded air-laid blank 10 as produced according to the method and by the system 100 of the present invention comprises significantly less non-bonded cellulose and / or lignocellulose fibers, fiber fragments and fines as compared to bonded air-laid blanks 10 produced according to prior art technologies. This means that the bonded air-laid blank 10 produces less linting. Furthermore, the low amount of polymer binder present in the bonded air-laid blank 10 means that the bonded air-laid blank 10 can be recycled in the paper or board recycling streams, preferably in the paper recycling stream.

[0137] The embodiments described above are to be understood as a few illustrative examples of the present invention. It will be understood by those skilled in the art that various modifications, combinations and changes may be made to the embodiments without departing from the scope of the present invention. In particular, different part solutions in the different embodiments can be combined in other configurations, where technically possible. The scope of the present invention is, however, defined by the appended claims.

Claims

CLAIMS1 . A method of producing a bonded air-laid blank (10), the method comprising: introducing (S1) a cellulose and / or lignocellulose material and a polymer binder into a forming head (110), wherein the cellulose and / or lignocellulose material comprises a recycled cellulose and / or lignocellulose material and defibrated pulp; capturing (S2) the cellulose and / or lignocellulose material and the polymer binder as an unbonded air-laid web (20) on a conveyor (120) arranged in connection with an outlet (113) of the forming head (110); and heating (S3) the unbonded air-laid web (20) to at least partly melt the polymer binder and bind the cellulose and / or lignocellulose material to form a bonded air-laid blank (10) comprising less than 10 % by weight of the polymer binder and at least 80 % by weight of the cellulose and / or lignocellulose material.

2. The method according to claim 1 , wherein the recycled cellulose and / or lignocellulose material comprises cellulose and / or lignocellulose material flakes (30).

3. The method according to claim 2, wherein the recycled cellulose and / or lignocellulose material comprises at least 75 % by weight of cellulose and / or lignocellulose material flakes (30), preferably at least 80 % by weight of cellulose and / or lignocellulose material flakes (30), and more preferably at least 85 % by weight of cellulose and / or lignocellulose material flakes (30).

4. The method according to claim 2 or 3, wherein surfaces of the cellulose and / or lignocellulose material flakes (30) are rough surfaces.

5. The method according to claim 4, wherein the surfaces of the cellulose and / or lignocellulose material flakes (30) comprises surface structures (35), preferably cellulose and / or lignocellulose fibers extending from the surfaces of the cellulose and / or lignocellulose material flakes (30).

6. The method according to any one of claims 2 to 5, wherein the cellulose and / or lignocellulose material flakes (30) have an average largest dimension selected within an interval of from 2 up to 20 mm, preferably selected within an interval of from 5 up to 15 mm, and more preferably have an average largest dimension and an average next largest dimension independently selected within an interval of from 2 up to 20 mm, preferably selected within an interval of from 5 up to 15 mm.

7. The method according to any one of claims 1 to 6, wherein the recycled cellulose and / or lignocellulose material comprises recycled post-industrial and / or post-consumer cellulose and / or lignocellulose material comprising the cellulose and / or lignocellulose material flakes (30).

8. The method according to any one of claims 1 to 6, further comprising milling (S12), preferably disc milling (S12), recycled post-industrial and / or post-consumer cellulose and / or lignocellulose material to form the recycled cellulose and / or lignocellulose material comprising the cellulose and / or lignocellulose material flakes (30) having a surface roughness.

9. The method according to claim 8, further comprising selecting (S11) at least one operational parameter of a disc mill based on the type of recycled post-industrial and / or post-consumer cellulose and / or lignocellulose material and a target surface roughness of the cellulose and / or lignocellulose material flakes (30) and / or a target density of the recycled cellulose and / or lignocellulose material, wherein the at least one operational parameter is selected from the group consisting of a disc gap of the disc mill, rotational speed(s) of the disc(s) of the disc mill, and flow rate of an air-flow transporting the shredded recycled post-industrial and / or post-consumer cellulose and / or lignocellulose material into the disc mill; and milling (S12) the recycled post-industrial and / or post-consumer cellulose and / or lignocellulose material comprises disc milling (S12) the recycled post-industrial and / or post-consumer cellulose and / or lignocellulose material with the disc mill operated according to the selected at least one operational parameter to form the recycled cellulose and / or lignocellulose material comprising the cellulose and / or lignocellulose material flakes (30), wherein the cellulose and / or lignocellulose material flakes (30) have the target surface roughness and / or the recycled cellulose and / or lignocellulose material has the target density.

10. The method according to any one of claims 1 to 6, further comprising: shredding (S10) recycled post-industrial and / or post-consumer cellulose and / or lignocellulosecontaining material to form shredded recycled cellulose and / or lignocellulose material; and milling (S12), preferably disc milling (S12), the shredded recycled cellulose and / or lignocellulose material to form the recycled cellulose and / or lignocellulose material comprising the cellulose and / or lignocellulose material flakes (30) having a surface roughness.

11. The method according to claim 10, further comprising selecting (S11) at least one operational parameter of a disc mill based on the type of recycled post-industrial and / or post-consumer cellulose and / or lignocellulose material and a target surface roughness of the cellulose and / or lignocellulose material flakes (30) and / or a target density of the recycled cellulose and / or lignocellulose material, wherein the at least one operational parameter is selected from the group consisting of a disc gap of the disc mill, rotational speed(s) of the disc(s) of the disc mill, and flow rate of an air-flow transporting the shredded recycled post-industrial and / or post-consumer cellulose and / or lignocellulose material into the disc mill; and milling (S12) the shredded recycled post-industrial and / or post-consumer cellulose and / or lignocellulose material comprises disc milling (S12) the shredded recycled post-industrial and / or postconsumer cellulose and / or lignocellulose material with the disc mill operated according to the selected at least one operational parameter to form the recycled cellulose and / or lignocellulose material comprising the cellulose and / or lignocellulose material flakes (30), wherein the cellulose and / or lignocellulose material flakes (30) have the target surface roughness and / or the recycled cellulose and / or lignocellulose material has the target density.

12. The method according to any one of claims 7 to 11 , wherein the recycled post-industrial and / or post-consumer cellulose and / or lignocellulose-containing material comprises: a recycled post-consumer cellulose and / or lignocellulose material selected from the group consisting of recycled paper, recycled printing paper, recycled newsprint, recycled paper board, recycled corrugated board, recycled cartonboard, recycled liner, recycled fluting, and any combination thereof; and / or a recycled post-industrial cellulose and / or lignocellulose material selected from the group consisting of chips, clips, clippings, waste, trim, trimmings, leftovers and / or scraps, preferably of paper, printing paper, newsprint, paper board, corrugated board, cartonboard, liner and / or fluting, from a paper- and / or board-making, -using or -converting process or facility.

13. The method according to any one of claims 7 to 12, wherein the recycled post-industrial and / or post-consumer cellulose and / or lignocellulose-containing material comprises Kraft liner material.

14. The method according to any one of claims 1 to 13, wherein the defibrated pulp is defibrated virgin pulp.

15. The method according to any one of claims 1 to 14, wherein the defibrated pulp is selected from the group consisting of defibrated sulfate pulp, defibrated sulfite pulp, defibrated thermomechanical pulp (TMP), defibrated high temperature thermomechanical pulp (HTMP), defibrated mechanical fiber intended for medium density fiberboard (MDF-fiber), defibrated chemi-thermomechanical pulp (CTMP), defibrated high temperature chemi-thermomechanical pulp (HTCTMP), and a combination thereof, preferably defibrated Kraft pulp, and more preferably defibrated unbleached Kraft pulp.

16. The method according to any one of claims 1 to 15, further comprising: mixing (S15) the recycled cellulose and / or lignocellulose material, the defibrated pulp and the polymer binder in one or more mixing operations; and transporting (S16) the mixture of the recycled cellulose and / or lignocellulose material, the defibrated pulp and the polymer binder by an air flow in a conduit (170) to the forming head (1 10).

17. The method according to any one of claims 1 to 16, wherein the cellulose and / or lignocellulose material comprises the defibrated pulp at an amount selected within an interval of from 2.5 up to 20 % by weight, preferably at an amount selected within an interval of from 5 up to 15 % by weight.

18. The method according to any one of claims 1 to 17, wherein the cellulose and / or lignocellulose material comprises the recycled cellulose and / or lignocellulose material at an amount selected within an interval of from 80 up to 97.5 % by weight, preferably at an amount selected within an interval of from 85 up to 95 % by weight.

19. The method according to any one of claims 1 to 18, wherein the bonded air-laid blank (10) comprises at least 80 % by weight, preferably at least 90 % by weight, more preferably at least 92.5 % by weight, even more preferably at least 95 % by weight, and most preferably at least 97.5 % by weight, of the cellulose and / or lignocellulose material.

20. The method according to any one of claims 1 to 19, wherein the bonded air-laid blank (10) comprises the polymer binder at a concentration selected within an interval of from 0.1 up to 7.5 % by weight, preferably selected within an interval of from 0.5 up to 5 % by weight, and more preferably selected within an interval of from 0.5 up to 2.5 % by weight.

21. The method according to any one of claims 1 to 20, wherein the polymer binder is selected from the group consisting of a polymer powder, polymer fibers, and a combination thereof, preferably selectedfrom the group consisting of a thermoplastic polymer powder, thermoplastic polymer fibers and a combination thereof, and more preferably thermoplastic polymer fibers.

22. The method according to claim 21, wherein the thermoplastic polymer fibers are selected from the group consisting of mono-component thermoplastic polymer fibers, bi-component thermoplastic polymer fibers and a mixture thereof, preferably bi-component thermoplastic polymer fibers.

23. The method according to claim 21 or 22, wherein the thermoplastic polymer fibers have an average length of less than 17.5 mm, preferably less than 15 mm, more preferably less than 12.5 mm and more preferably less than 10 mm.

24. The method according to any one of claims 1 to 23, wherein the polymer binder is made from I) a material selected from the group consisting of polyvinyl alcohol (PVOH), thermoplastic starch (TPS), polyethylene (PE), ethylene acrylic acid copolymer (EAA), ethylene-vinyl acetate (EVA), polypropylene (PP), polystyrene (PS), polybutylene adipate terephthalate (PBAT), polybutylene succinate (PBS), polylactic acid (PLA), polyethylene terephthalate (PET), polycaprolactone (PCL), polyvinyl alcohol (PVA), polyethylene glycol (PEG), poly (2-ethyl-2-oxazoline) (PEOX), polyvinyl ether (PVE), polyvinylpyrrolidone (PVP), polyacrylic acid (PAA), polymethacrylic acid (PMAA), polyvinyl acetate (PVAc), polyurethane (PU), copolymers thereof and mixtures thereof, and ii) optionally one or more additives.

25. A bonded air-laid blank (10) comprising: at least 80 % by weight of a cellulose and / or lignocellulose material comprising a recycled cellulose and / or lignocellulose material and defibrated pulp; and less than 10 % by weight of a polymer binder binding together the recycled cellulose and / or lignocellulose material and the defibrated pulp.

26. The bonded air-laid blank according to claim 25, wherein the recycled cellulose and / or lignocellulose material comprises cellulose and / or lignocellulose material flakes (30).

27. The bonded air-laid blank according to claim 26, wherein the recycled cellulose and / or lignocellulose material comprises at least 75 % by weight of cellulose and / or lignocellulose material flakes (30), preferably at least 80 % by weight of cellulose and / or lignocellulose material flakes (30), and more preferably at least 85 % by weight of cellulose and / or lignocellulose material flakes (30).

28. The bonded air-laid blank according to claim 26 or 27, wherein surfaces of the cellulose and / or lignocellulose material flakes (30) are rough surfaces.

29. The bonded air-laid blank according to claim 28, wherein the surfaces of the cellulose and / or lignocellulose material flakes (30) comprises surface structures (35), preferably cellulose and / or lignocellulose fibers extending from the surfaces of the cellulose and / or lignocellulose material flakes (30).

30. The bonded air-laid blank according to any one of claims 26 to 29, wherein the cellulose and / or lignocellulose material flakes (30) have an average largest dimension selected within an interval of from 2 up to 20 mm, preferably selected within an interval of from 5 up to 15 mm, and more preferably have an average largest dimension and an average next largest dimension independently selected within an interval of from 2 up to 20 mm, preferably selected within an interval of from 5 up to 15 mm.31 . The bonded air-laid blank according to any one of claims 26 to 30, wherein the recycled cellulose and / or lignocellulose material comprises recycled post-industrial cellulose and / or lignocellulose material comprising the cellulose and / or lignocellulose material flakes (30).

32. The bonded air-laid blank according to any one of claims 26 to 30, wherein the recycled cellulose and / or lignocellulose material comprises milled, preferably disc milled, post-industrial and / or postconsumer cellulose and / or lignocellulose material comprising the cellulose and / or lignocellulose material flakes (30) having a surface roughness.

33. The bonded air-laid blank according to any one of claims 26 to 30, wherein the recycled cellulose and / or lignocellulose material comprises shredded and milled, preferably disc milled, post-industrial and / or post-consumer cellulose and / or lignocellulose material comprising the cellulose and / or lignocellulose material flakes (30) having a source roughness.

34. The bonded air-laid blank according to any one of claims 31 to 33, wherein the recycled post-consumer cellulose and / or lignocellulose material is selected from the group consisting of recycled paper, recycled printing paper, recycled newsprint, recycled paper board, recycled corrugated board, recycled cartonboard, recycled liner, recycled fluting, and any combination thereof; and / orthe recycled post-industrial cellulose and / or lignocellulose material is selected from the group consisting of chips, clips, clippings, waste, trim, trimmings, leftovers and / or scraps, preferably of paper, printing paper, newsprint, paper board, corrugated board, cartonboard, liner and / or fluting, from a paper- and / or board-making, -using or -converting process or facility.

35. The bonded air-laid blank according to any one of claims 31 to 34, wherein the recycled postindustrial and / or post-consumer cellulose and / or lignocellulose-containing material comprises Kraft liner material.

36. The bonded air-laid blank according to any one of claims 25 to 35, wherein the defibrated pulp is defibrated virgin pulp.

37. The bonded air-laid blank according to any one of claims 25 to 36, wherein the defibrated pulp is selected from the group consisting of defibrated sulfate pulp, defibrated sulfite pulp, defibrated thermomechanical pulp (TMP), defibrated high temperature thermomechanical pulp (HTMP), defibrated mechanical fiber intended for medium density fiberboard (MDF-fiber), defibrated chemi- thermomechanical pulp (CTMP), defibrated high temperature chemi-thermomechanical pulp (HTCTMP), and a combination thereof, preferably defibrated Kraft pulp, and more preferably defibrated unbleached Kraft pulp.

38. The bonded air-laid blank according to any one of claims 25 to 37, the cellulose and / or lignocellulose material comprises the defibrated pulp at an amount selected within an interval of from 2.5 up to 20 % by weight, preferably at an amount selected within an interval of from 5 up to 15 % by weight.

39. The bonded air-laid blank according to any one of claims 25 to 38, the cellulose and / or lignocellulose material comprises the recycled cellulose and / or lignocellulose material at an amount selected within an interval of from 80 up to 97.5 % by weight, preferably at an amount selected within an interval of from 85 up to 95 % by weight.

40. The bonded air-laid blank according to any one of claims 25 to 39, wherein the bonded air-laid blank (10) comprises at least 80 % by weight, preferably at least 90 % by weight, more preferably at least 92.5 % by weight, even more preferably 95 % by weight, and most preferably at least 97.5 % by weight, of the cellulose and / or lignocellulose material.

41. The bonded air-laid blank according to any one of claims 25 to 40, wherein the bonded air-laid blank (10) comprises the polymer binder at a concentration selected within an interval of from 0.1 up to7.5 % by weight, preferably selected within an interval of from 0.5 up to 5 % by weight, and more preferably selected within an interval of from 0.5 up to 2.5 % by weight.

42. The bonded air-laid blank according to any one of claims 25 to 41, wherein the polymer binder is selected from the group consisting of a polymer powder, polymer fibers, and a combination thereof, preferably selected from the group consisting of a thermoplastic polymer powder, thermoplastic polymer fibers and a combination thereof, and more preferably thermoplastic polymer fibers.

43. The bonded air-laid blank according to claim 42, wherein the thermoplastic polymer fibers are selected from the group consisting of mono-component thermoplastic polymer fibers, bi-component thermoplastic polymer fibers and a mixture thereof, preferably bi-component thermoplastic polymer fibers.

44. The bonded air-laid blank according to claim 42 or 43, wherein the thermoplastic polymer fibers have an average length of less than 17.5 mm, preferably less than 15 mm, more preferably less than12.5 mm and more preferably less than 10 mm.

45. The bonded air-laid blank according to any one of claims 25 to 44, wherein the polymer binder is made from I) a material selected from the group consisting of polyvinyl alcohol (PVOH), thermoplastic starch (TPS), polyethylene (PE), ethylene acrylic acid copolymer (EAA), ethylene-vinyl acetate (EVA), polypropylene (PP), polystyrene (PS), polybutylene adipate terephthalate (PBAT), polybutylene succinate (PBS), polylactic acid (PLA), polyethylene terephthalate (PET), polycaprolactone (PCL), polyvinyl alcohol (PVA), polyethylene glycol (PEG), poly (2-ethyl-2-oxazoline) (PEOX), polyvinyl ether (PVE), polyvinylpyrrolidone (PVP), polyacrylic acid (PAA), polymethacrylic acid (PMAA), polyvinyl acetate (PVAc), polyurethane (PU), copolymers thereof and mixtures thereof, and ii) optionally one or more additives.

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