Recyclable bonded air-laid blanks

Abstract

A method of producing a bonded air-laid blank (10) comprises introducing recycled cellulose and / or lignocellulose material and polymer binder fibers into a forming head (110). The recycled cellulose and / or lignocellulose material comprises at least 75 % by weight of cellulose and / or lignocellulose material flakes (30) having an average largest dimension selected within an interval of from 2 up to 20 mm. The polymer binder fibers have an average length of less than 17.5 mm. The method also comprises capturing the recycled cellulose and / or lignocellulose material and the polymer binder fibers 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 fibers and bind the recycled cellulose and / or lignocellulose material to form a bonded air-laid blank (10) comprising less than 10 % by weight of the polymer binder fibers and at least 80 % by weight of the recycled 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 material fibers and polymer binder fibers 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 material fibers are bonded by the polymer binder fibers. 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 material fibers in the air-laying process. These materials, however, demand a comparatively high amount of polymer binder fibers to keep the cellulose and / or lignocellulose material fibers together in the bonded air-laid blank. The high amount of polymer binder fibers 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 recycled cellulose and / or lignocellulose material and polymer binder fibers into a forming head. The recycled cellulose and / or lignocellulose material comprises at least 75 % by weight of cellulose and / or lignocellulose material flakes. The cellulose and / or lignocellulose material flakes have an average largest dimension selected within an interval of from 2 up to 20 mm. The polymer binder fibers have an average length of less than 17.5 mm. The method also comprises capturing the recycled cellulose and / or lignocellulose material and the polymer binder fibers 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 fibers and bind the recycled cellulose and / or lignocellulose material to form a bonded air-laid blank comprising less than 10 % by weight of the polymer binder fibers and at least 80 % by weight of the recycled cellulose and / or lignocellulose material. Another aspect relates to a bonded air-laid blank comprising at least 80 % by weight of a recycled cellulose and / or lignocellulose material comprising at least 75 % by weight of cellulose and / or lignocellulose material flakes. The cellulose and / or lignocellulose material flakes have an average largest dimension selected within an interval of from 2 up to 20 mm. The bonded air-laid blank also comprises less than 10 % by weight of polymer binder fibers binding together the recycled cellulose and / or lignocellulose material. The polymer binder fibers have an average length of less than 17.5 mm.

[0015] The present invention produces bonded air-laid blanks with a comparatively low amount of polymer binder fibers by using a recycled cellulose and / or lignocellulose material comprising a high amount of cellulose and / or lignocellulose material flakes having an average largest dimension selected within an interval of from 2 up to 20 mm. These flakes remain within the bonded air-laid blank even with a low amount of polymer binder fibers. 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 fibers. Another advantage of using the recycled cellulose and / or lignocellulose material in the air-laying process is that the recycled cellulose and / or lignocellulose material comprises less non-fibrous cellulose and / or lignocellulose material particles, or fines, that otherwise may cause linting or dusting during production and handling of the bonded air-laid blank, and products produced therefrom.

[0016] BRIEF DESCRIPTION OF THE DRAWINGS

[0017] 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:

[0018] Fig. 1 is a perspective view of a bonded air-laid blank according to an embodiment;

[0019] Fig. 2 schematically illustrates a cellulose and / or lignocellulose material flake;

[0020] Fig. 3 is a flow chart illustrating a method of producing an air-laid blank according to an embodiment;

[0021] Fig. 4 is a flow chart illustrating additional, optional steps of the method in Fig. 3 according to various embodiments; and

[0022] Fig. 5 is a schematic illustration of a system for producing an air-laid blank according to various embodiments. DETAILED DESCRIPTION

[0023] 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.

[0024] 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.

[0025] 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 material fibers in the form of individual or free fibers. Thus, in the art, pulp, such as in the form of sulfate pulp, sulfite pulp, thermomechanical pulp (TMP), high temperature thermomechanical pulp (HTMP), mechanical fiber intended for medium density fiberboard (MDF-fiber), chemi-thermomechanical pulp (CTMP), high temperature chemi-thermomechanical pulp (HTCTMP), and a combination thereof, is used as raw material and defibrated into defibrated cellulose and / or lignocellulose fiber material. 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 pulp, however, does not only contain the desired cellulose and / or lignocellulose material 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 material 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 material fibers, fiber fragments and fines that have not been sufficiently bonded by the polymer binder fibers either on the surfaces or within the bonded air-laid blanks. The lint or dust may constitute aesthetic problems for products produced 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, nonbonded cellulose and / or lignocellulose material 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 material 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 nonbonded cellulose and / or lignocellulose material fibers, fiber fragments and fines.

[0026] A solution to such a linting problem in the art has been to use a comparatively high amount of polymer binder fibers to bind and thereby capture the cellulose and / or lignocellulose material fibers, fiber fragments and fines in the bonded air-laid blank. However, if the amount of the polymer binder fibers 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 fibers should be low. However, a low amount of polymer binder fibers 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.

[0027] 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 fibers. This is possible by using recycled cellulose and / or lignocellulose material as the major constituent of the bonded air-laid blank. Further, this recycled cellulose and / or lignocellulose material comprises at least 75 % by weight of cellulose and / or lignocellulose material flakes having an average largest dimension selected within an interval of from 2 up to 20 mm. Thus, the cellulose and / or lignocellulose material used according to the invention is recycled, such as reclaimed or re-used, cellulose and / or lignocellulose material. For instance, recycled post-industrial and / or post-consumer cellulose and / or lignocellulose material could be processed into a recycled cellulose and / or lignocellulose material comprising at least 75 % by weight of cellulose and / or lignocellulose material flakes having an average largest dimension selected within an interval of from 2 up to 20 mm. Such a recycled cellulose and / or lignocellulose material has the advantage over defibrated cellulose and / or lignocellulose fiber material in terms of containing a lower amount of fiber fragments and fines. Accordingly, lower amounts of polymer binder fibers are needed to bind the cellulose and / or lignocellulose material flakes 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 fibers 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 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 board-making, -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.

[0028] The present invention therefore relates to a method of producing a bonded air-laid blank 10, see Figs. 1 , 2, 3, and 5. The method comprises introducing, in step S1 , recycled cellulose and / or lignocellulose material and polymer binder fibers into a forming head 110. The recycled cellulose and / or lignocellulose material comprises at least 75 % by weight of cellulose and / or lignocellulose material flakes 30. The cellulose and / or lignocellulose material flakes 30 have an average largest dimension selected within an interval of from 2 up to 20 mm. The polymer binder fibers have an average length of less than 17.5 mm. The recycled cellulose and / or lignocellulose material and the polymer binder fibers are captured in step S2 as an unbonded air-laid web 20 on a conveyor 120 arranged in connection with an outlet 1 13 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 fibers and bind the recycled cellulose and / or lignocellulose material to form a bonded air-laid blank 10 comprising less than 10 % by weight of the polymer binder fibers and at least 80 % by weight of the recycled cellulose and / or lignocellulose material. The heating as applied in step S3 will partly melt the polymer binder fibers to become tacky and adhere to the recycled cellulose and / or lignocellulose material, including the cellulose and / or lignocellulose material flakes 30, in the unbonded air-laid web 20 to thereby form the bonded air-laid blank 10. Most of free cellulose and / or lignocellulose material particles, including any fiber fragments and fines, in the unbonded air-laid web 20 will thereby be bonded together by the polymer binder fibers forming the porous, open cell foam like structure of the bonded air-laid blank 10.

[0029] The recycled cellulose and / or lignocellulose material comprises cellulose and / or lignocellulose comprised or present in cellulose and / or lignocellulose material flakes 30, i.e., 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 mainly in the form of cellulose and / or lignocellulose material 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 used according to the invention as compared to defibrated cellulose and / or lignocellulose fiber material. The reduced amount of polymer binder fibers, i.e., less than 10 % by weight, used by the invention is sufficient to bind the cellulose and / or lignocellulose material flakes 30 into a bonded air-laid blank 10 and still capture most of any fiber fragments and fines present in the recycled 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 fibers, and still have reduced linting and dusting.

[0030] 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.

[0031] In an embodiment, any cellulose and / or lignocellulose material in the recycled cellulose and / or lignocellulose material that is in the form of 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, in this embodiment, selected within an interval of from 2 up to 20 mm.

[0032] 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 at least 75 % by weight of cellulose and / or lignocellulose material flakes 30 having the average largest dimension within an interval of from 2 up to 20 mm.

[0033] 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 at least 75 % by weight of cellulose and / or lignocellulose material flakes 30 having the average largest dimension within an interval of from 2 up to 20 mm. 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.

[0034] 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.

[0035] 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 that is introduced into the forming head 110 in step S1 . Such further embodiments will be described further with reference to Fig. 4.

[0036] 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 at least 75 % by weight of cellulose and / or lignocellulose material flakes 30 having the average largest dimension selected within an interval of from 2 up to 20 mm. In this embodiment, the cellulose and / or lignocellulose material flakes 30 additionally have a surface roughness.

[0037] 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.

[0038] 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 at least 75 % by weight of cellulose and / or lignocellulose material flakes 30 having the average largest dimension selected within an interval of from 2 up to 20 mm and having the surface roughness.

[0039] 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 at least 75 % by weight of cellulose and / or lignocellulose material flakes 30 having the average largest dimension selected within an interval of from 2 up to 20 mm and having the surface roughness.

[0040] 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 fibers. 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 fibers to the cellulose and / or lignocellulose material flakes 30 during the heating step S3 in Fig. 3.

[0041] 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.

[0042] 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 at least 75 % by weight of cellulose and / or lignocellulose material flakes 30 having the average largest dimension selected within an interval of from 2 up to 20 mm. 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] 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 fibers 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 fibers even at low amounts of polymer binder fibers in the bonded air-laid blank 10. 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.

[0050] 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 .

[0051] 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.

[0052] 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 at least 75 % by weight of cellulose and / or lignocellulose material flakes 30 having the average largest dimension selected within an interval of from 2 up to 20 mm and having a surface roughness.

[0053] 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 at least 75 % by weight of cellulose and / or lignocellulose material flakes 30 having the average largest dimension selected within an interval of from 2 up to 20 mm. 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.

[0054] The cellulose and / or lignocellulose material flakes 30 of the recycled cellulose and / or lignocellulose material, such as produced as shown in Fig. 4, 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.

[0055] 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.

[0056] 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.

[0057] 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 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 fibers. This means that a higher amount of polymer binder fibers 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.

[0058] 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. 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 example, 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.

[0060] Thus, 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 recycled paper, recycled printing paper, recycled newsprint, recycled paper board, recycled corrugated board, recycled cartonboard, recycled liner, recycled fluting, and any combination thereof.

[0061] 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.

[0062] 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. In an embodiment, the method comprises mixing the recycled cellulose and / or lignocellulose material and the polymer binder fibers to form a mixture of the recycled cellulose and / or lignocellulose material and the polymer binder fibers. In such an embodiment, step S1 of Fig. 3 comprises introducing the mixture of the recycled cellulose and / or lignocellulose material and the polymer binder fibers into the forming head 110.

[0066] In an embodiment, the method comprises an additional step S13 as shown in Fig. 4. The method optionally, but preferably, continues from step S12 in Fig. 4. A next step S13 comprises transporting a mixture of the recycled cellulose and / or lignocellulose material and the polymer binder fibers by an air flow in a conduit 170 to the forming head 1 10. The method then continues to step S1 in Fig. 3. Hence, in a preferred embodiment, the recycled cellulose and / or lignocellulose material and the polymer binder fibers are preferably introduced into the forming head 110 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 110.

[0067] 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 and the polymer binder fibers 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 and the polymer binder fibers into separate inlets 111 of the forming head 110. 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 and at least one conduit arranged to convey an air flow of the polymer binder fibers. In this embodiment, the mixing of the recycled cellulose and / or lignocellulose material and the polymer binder fibers is taking place first within the forming head 110.

[0068] 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.

[0069] The recycled cellulose and / or lignocellulose material and the polymer binder fibers are introduced in step S1 of Fig. 3 into the forming head 1 10, 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 and the polymer binder fibers 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 1 10 may include equipment arranged inside the forming head 1 10 to promote separation and mixing of the recycled cellulose and / or lignocellulose material and the polymer binder fibers 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.

[0070] The recycled cellulose and / or lignocellulose material and the polymer binder fibers or the mixture thereof pass(es) through the forming head 110 to the outlet 113, such as arranged in connection with a lower end 1 14 of the forming head 110 and is further mixed through this passage. The mixture of the recycled cellulose and / or lignocellulose material and the polymer binder fibers 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 and the polymer binder fibers 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 and the polymer binder fibers to the outlet 113 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.

[0071] 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 and the polymer binder fibers 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 flakes 30 in the recycled cellulose and / or lignocellulose material and the polymer binder fibers from passing through the air-permeable conveyor 120. Hence, the recycled cellulose and / or lignocellulose material and the polymer binder fibers are instead deposited as a mixture onto the air-permeable conveyor 120 in the form of an unbonded air-laid web 20.

[0072] 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.

[0073] 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 fibers 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 air-laid web 20 to melt or partially melt the polymer binder fibers. The polymer binder fibers thereby become tacky and adhere to the recycled cellulose and / or lignocellulose material and, thus, holds the cellulose and / or lignocellulose material flakes 30 together and thereby results in a bonded air-laid blank 10.

[0074] 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 in the unbonded air-laid web 20.

[0075] 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 flake structures 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 fibers 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.

[0076] 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.

[0077] 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 fibers solidify sufficiently.

[0078] 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.

[0079] 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.

[0080] 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.

[0081] 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).

[0082] 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.

[0083] Another aspect of the invention relates to a bonded air-laid blank 10 comprising at least 80 % by weight of a recycled cellulose and / or lignocellulose material comprising at least 75 % by weight of cellulose and / or lignocellulose material flakes 30. The cellulose and / or lignocellulose material flakes 30 have an average largest dimension selected within an interval of from 2 up to 20 mm. The bonded air-laid blank 10 also comprises less than 10 % by weight of polymer binder fibers binding together the recycled cellulose and / or lignocellulose material. The polymer binder fibers have an average length of less than 17.5 mm.

[0084] 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 having the average largest dimension selected within an interval of from 2 up to 20 mm, and less than 25 % by weight of 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.

[0085] In an embodiment, the recycled cellulose and / or lignocellulose material comprises cellulose and / or lignocellulose material particles at a concentration selected within an interval of from 2.5 up to 20 % by weight. In a preferred embodiment, the recycled cellulose and / or lignocellulose material comprises cellulose and / or lignocellulose material particles at a concentration selected within an interval of from 5 up to 17.5 % by weight, preferably selected within an interval of from 7.5 up to 15 % by weight, and most preferably selected within an interval of from 10 up to 15 % by weight.

[0086] The cellulose and / or lignocellulose material particles preferably comprises cellulose and / or lignocellulose material fibers, cellulose and / or lignocellulose material fiber fragments and cellulose and / or lignocellulose material fines. Although, the amount of these smaller cellulose and / or lignocellulose material particles should be kept low, i.e., preferably less than 25 % by weight of the recycled cellulose and / or lignocellulose material, the cellulose and / or lignocellulose material particles provides desired characteristics to the bonded air-laid blank 10. In particular, the cellulose and / or lignocellulose material particles contribute to the insulating properties of the bonded air-laid blank 10. Thus, it is actually advantageous if the bonded air-laid blank 10 comprises some, i.e., no more than 25 % by weight, of the cellulose and / or lignocellulose material particles in addition to the cellulose and / or lignocellulose material flakes 30.

[0087] In an embodiment, the average largest dimension of the cellulose and / or lignocellulose material particles is below 10 mm, preferably below 5 mm and more preferably below 2 mm with the proviso that the average largest dimension of the cellulose and / or lignocellulose material particles is smaller than the average largest dimension of the cellulose and / or lignocellulose material flakes 30.

[0088] In an embodiment, the recycled cellulose and / or lignocellulose material comprises at least 80 % by weight of cellulose and / or lignocellulose material flakes 30. In a preferred embodiment, the recycled cellulose and / or lignocellulose material comprises at least 85 % by weight of cellulose and / or lignocellulose material flakes 30.

[0089] 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 material fibers, or fiber fragments and smaller fines.

[0090] In a particular embodiment, the recycled cellulose and / or lignocellulose material only or substantially only comprises 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 the 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 the 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.

[0091] 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 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 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.

[0092] In an embodiment, the recycled cellulose and / or lignocellulose material comprises recycled postindustrial and / or post-consumer cellulose and / or lignocellulose material comprising at least 75 % by weight of cellulose and / or lignocellulose material flakes 30 having an average largest dimension selected within an interval of from 2 up to 20 mm.

[0093] 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 at least 75 % by weight of cellulose and / or lignocellulose material flakes 30 having an average largest dimension selected within an interval of from 2 up to 20 mm and a surface roughness.

[0094] 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 at least 75 % by weight of cellulose and / or lignocellulose material flakes 30 having an average largest dimension selected within an interval of from 2 up to 20 mm and a surface roughness.

[0095] In an embodiment, the bonded air-laid blank 10 comprises at least 80 % by weight of the recycled 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 recycled cellulose and / or lignocellulose material.

[0096] In an embodiment, the bonded air-laid blank 10 comprises the polymer binder fibers 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 fibers 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 3.5 % by weight, and more preferably 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. 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 %.

[0097] 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.

[0098] The polymer binder fibers are 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 fibers may also assist in building up the foam-like structure of the bonded air-laid blank 10. The polymer binder fibers are, in such an embodiment, intermingled with the recycled cellulose and / or lignocellulose material during the air-laying process forming a mixture.

[0099] The polymer binder fibers 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 a high amount, i.e., at least 75 % by weight, of the 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 airlaid 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 recycled cellulose and / or lignocellulose material comprising a high amount of cellulose and / or lignocellulose material flakes 30 and polymer binder fibers having an average length above 17.5 mm tend to form a layered structure. The recycled 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.

[0100] 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.

[0101] The polymer binder used in the bonded air-laid blank 10 comprises polymer binder fibers, but may also comprise other polymer binder material in addition to the polymer binder fibers, such as polymer binder powder.

[0102] The polymer binder fibers could be natural or synthetic polymer binder fibers, or a mixture of natural polymer binder fibers, a mixture of synthetic polymer binder fibers, or a mixture of natural and synthetic polymer binder fibers, but is preferably thermoplastic polymer binder fibers.

[0103] In an embodiment, the polymer binder fibers are thermoplastic polymer fibers.

[0104] In an embodiment, the polymer binder fibers 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 styrenebutadiene 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.

[0105] Hence, in an embodiment, the polymer binder fibers are made of a material selected from the above- mentioned group. In another embodiment, the polymer binder fibers are made of a material selected from the above-mentioned group and one or more additives.

[0106] In an embodiment, the polymer binder fibers are or comprise, such as consist of, mono-component and / or bi-component 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.

[0107] In an embodiment, the polymer binder fibers are or comprise, such as consist 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 fibers are or comprise, such as consist 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 fibers are or comprise, such as consist 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.

[0108] The thermoplastic polymer binder fibers could comprise 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 thermoplastic polymer binder fibers comprising one or multiple, i.e., two or more, different monocomponent thermoplastic polymer fibers made of different materials and / or one or multiple different bi- component thermoplastic polymer fibers made of different materials. 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.

[0109] The bonded air-laid blank 10 may comprise one or more additives in addition to the recycled cellulose and / or lignocellulose material and the polymer binder fibers. One or more additives could be added to the polymer binder fibers and / or added when producing the polymer binder fibers. Alternatively, or in addition, one or more additives could be added to the recycled cellulose and / or lignocellulose material. Alternatively, or in addition, one or more additives could be added to the mixture of the recycled cellulose and / or lignocellulose material and the polymer binder fibers, such as during the air-laying process or prior to the air-laying process.

[0110] Illustrative, but non-limiting, examples of such additives include electrically conducting or semiconducting fillers, coupling agents, flame retardants, dyes, impact modifiers, hydrophobization agents, etc.

[0111] 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.

[0112] 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.

[0113] 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.

[0114] 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 fibers 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. 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) recycled cellulose and / or lignocellulose material and polymer binder fibers into a forming head (110), wherein the recycled cellulose and / or lignocellulose material comprises at least 75 % by weight of cellulose and / or lignocellulose material flakes (30), 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; and the polymer binder fibers have an average length of less than 17.5 mm; capturing (S2) the recycled cellulose and / or lignocellulose material and the polymer binder fibers 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 fibers and bind the recycled cellulose and / or lignocellulose material to form a bonded air-laid blank (10) comprising less than 10 % by weight of the polymer binder fibers and at least 80 % by weight of the recycled cellulose and / or lignocellulose material.

2. The method according to claim 1 , wherein the recycled cellulose and / or lignocellulose material comprises: at least 75 % by weight of 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 less than 25 % by weight of cellulose and / or lignocellulose material particles having an average largest dimension that is smaller than the average largest dimension of the cellulose and / or lignocellulose material flakes (30).

3. The method according to claim 2, wherein the recycled cellulose and / or lignocellulose material comprises the cellulose and / or lignocellulose material particles at a concentration selected within an interval of from 2.5 up to 20 % by weight, preferably selected within an interval of from 5 up to 17.5 % by weight, more preferably selected within an interval of from 7.5 up to 15 % by weight, and even more preferably selected within an interval of from 10 up to 15 % by weight.

4. The method according to claim 2 or 3, wherein the average largest dimension of the cellulose and / or lignocellulose material particles is below 10 mm, preferably below 5 mm and more preferably below 2 mm, with the proviso that the average largest dimension of the cellulose and / or lignocellulosematerial particles is smaller than the average largest dimension of the cellulose and / or lignocellulose material flakes (30).

5. The method according to any one of claims 2 to 4, wherein 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.

6. The method according to any one of claims 1 to 5, wherein 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).

7. The method according to any one of claims 1 to 6, wherein the cellulose and / or lignocellulose material flakes (30) have the 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.

8. The method according to any one of claims 1 to 7, wherein the cellulose and / or lignocellulose material flakes (30) have the average largest dimension selected within an interval of from 5 up to 15 mm.

9. The method according to any one of claims 1 to 8, 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 recycled cellulose and / or lignocellulose material.

10. The method according to any one of claims 1 to 9, wherein the bonded air-laid blank (10) comprises the polymer binder fibers 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, more preferably selected within an interval of from 0.5 up to 3.5 % by weight, and most preferably from 0.5 up to 2.5 % by weight.

11. The method according to any one of claims 1 to 10, wherein the recycled cellulose and / or lignocellulose material comprises recycled post-industrial and / or post-consumer cellulose and / or lignocellulose material comprising at least 75 % by weight of cellulose and / or lignocellulose material flakes (30) having the average largest dimension selected within an interval of from 2 up to 20 mm.

12. The method according to any one of claims 1 to 10, further comprising milling (S12) recycled postindustrial and / or post-consumer cellulose and / or lignocellulose material to form the recycled cellulose and / or lignocellulose material comprising at least 75 % by weight of cellulose and / or lignocellulose material flakes (30) having i) the average largest dimension selected within an interval of from 2 up to 20 mm and ii) a surface roughness.

13. The method according to claim 12, wherein milling (S12) the recycled post-industrial and / or postconsumer cellulose and / or lignocellulose material comprises disc milling the recycled post-industrial and / or post-consumer cellulose and / or lignocellulose material to form the recycled cellulose and / or lignocellulose material comprising at least 75 % by weight of cellulose and / or lignocellulose material flakes (30) having i) the average largest dimension selected within an interval of from 2 up to 20 mm and ii) the surface roughness.

14. The method according to claim 13, 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 disc 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 at least 75 % by weight of cellulose and / or lignocellulose material flakes (30) having the average largest dimension selected within an interval of from 2 up to 20 mm, 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.

15. The method according to any one of claims 1 to 10, further comprising:shredding (S10) recycled post-industrial and / or post-consumer cellulose and / or lignocellulose material to form shredded recycled post-industrial and / or post-consumer cellulose and / or lignocellulose material comprising cellulose and / or lignocellulose material flakes (30); and milling (S12) the shredded recycled post-industrial and / or post-consumer cellulose and / or lignocellulose material to form the recycled cellulose and / or lignocellulose material comprising at least 75 % by weight of cellulose and / or lignocellulose material flakes (30) having i) the average largest dimension selected within an interval of from 2 up to 20 mm and ii) a surface roughness.

16. The method according to claim 15, wherein milling (S12) the shredded recycled post-industrial and / or post-consumer cellulose and / or lignocellulose material comprises disc 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 at least 75 % by weight of cellulose and / or lignocellulose material flakes (30) having i) the average largest dimension selected within an interval of from 2 up to 20 mm and ii) the surface roughness.

17. The method according to claim 16, 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 disc 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 at least 75 % by weight of cellulose and / or lignocellulose material flakes (30) having the average largest dimension selected within an interval of from 2 up to 20 mm, 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.

18. The method according to any one of claims 12 to 17, wherein the recycled cellulose and / or lignocellulose material following milling has a lower density than the recycled post-industrial and / or postconsumer cellulose and / or lignocellulose material prior to milling.

19. The method according to any one of claims 12 to 18, wherein the surfaces of the cellulose and / or lignocellulose material flakes (30) comprise surface structures (35), preferably cellulose and / or lignocellulose material fibers extending from the surfaces of the cellulose and / or lignocellulose material flakes (30).

20. The method according to any one of claims 11 to 19, wherein the recycled post-industrial and / or post-consumer cellulose and / or lignocellulose 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.

21. The method according to any one of claims 11 to 20, wherein the recycled post-industrial and / or post-consumer cellulose and / or lignocellulose material comprises Kraft liner material.

22. The method according to any one of claims 1 to 21 , further comprising transporting (S13) a mixture of the recycled cellulose and / or lignocellulose material and the polymer binder fibers by an air flow in a conduit (170) to the forming head (110).

23. The method according to any one of claims 1 to 22, wherein the polymer binder fibers are thermoplastic polymer fibers.

24. The method according to claim 23, 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.

25. The method according to any one of claims 1 to 24, wherein the polymer binder fibers are 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.

26. The method according to any one of claims 1 to 25, wherein the polymer binder fibers have an average length of less than 15 mm, preferably less than 12.5 mm and more preferably less than 10 mm.

27. A bonded air-laid blank (10) comprising: at least 80 % by weight of a recycled cellulose and / or lignocellulose material comprising at least 75 % by weight of cellulose and / or lignocellulose material flakes (30), 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; and less than 10 % by weight of polymer binder fibers binding together the recycled cellulose and / or lignocellulose material, wherein the polymer binder fibers have an average length of less than 17.5 mm.

28. The bonded air-laid blank according to claim 27, wherein the recycled cellulose and / or lignocellulose material comprises: at least 75 % by weight of cellulose and / or lignocellulose material flakes (30) having the average largest dimension selected within an interval of from 2 up to 20 mm; and less than 25 % by weight of cellulose and / or lignocellulose material particles having an average largest dimension that is smaller than the average largest dimension of the cellulose and / or lignocellulose material flakes (30).

29. The bonded air-laid blank according to claim 28, wherein the recycled cellulose and / or lignocellulose material comprises the cellulose and / or lignocellulose material particles at a concentration selected within an interval of from 2.5 up to 20 % by weight, preferably selected within an interval of from 5 up to 17.5 % by weight, more preferably selected within an interval of from 7.5 up to 15 % by weight, and even more preferably selected within an interval of from 10 up to 15 % by weight.

30. The bonded air-laid blank according to claim 28 or 29, wherein the average largest dimension of the cellulose and / or lignocellulose material particles is below 10 mm, preferably below 5 mm and more preferably below 2 mm, with the proviso that the average largest dimension of the cellulose and / or lignocellulose material particles is smaller than the average largest dimension of the cellulose and / or lignocellulose material flakes (30).

31. The bonded air-laid blank according to any one of claims 28 to 30, wherein 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.

32. The bonded air-laid blank according to any one of claims 27 to 31 , wherein 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).

33. The bonded air-laid blank according to any one of claims 27 to 32, wherein surfaces of the cellulose and / or lignocellulose material flakes (30) are rough surfaces.

34. The bonded air-laid blank according to claim 33, wherein the surfaces of the cellulose and / or lignocellulose material flakes (30) comprise surface structures (35), preferably cellulose and / or lignocellulose material fibers extending from the surfaces of the cellulose and / or lignocellulose material flakes (30).

35. The bonded air-laid blank according to any one of claims 27 to 34, wherein the cellulose and / or lignocellulose material flakes (30) have the 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.

36. The bonded air-laid blank according to any one of claims 27 to 35, wherein the cellulose and / or lignocellulose material flakes (30) have the average largest dimension selected within an interval of from 5 up to 15 mm.

37. The bonded air-laid blank according to any one of claims 27 to 36, 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 recycled cellulose and / or lignocellulose material.

38. The bonded air-laid blank according to any one of claims 27 to 37, wherein the bonded air-laid blank (10) comprises the polymer binder fibers 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, more preferably selected within an interval of from 0.5 up to 3.5 % by weight, and most preferably from 0.5 up to 2.5 % by weight.

39. The bonded air-laid blank according to any one of claims 27 to 38, wherein the recycled cellulose and / or lignocellulose material comprises recycled post-industrial cellulose and / or lignocellulose material comprising at least 75 % by weight of cellulose and / or lignocellulose material flakes (30) having the average largest dimension selected within an interval of from 2 up to 20 mm.

40. The bonded air-laid blank according to any one of claims 27 to 38, wherein the recycled cellulose and / or lignocellulose material comprises milled, preferably disc milled, post-industrial and / or postconsumer cellulose and / or lignocellulose material comprising at least 75 % by weight of cellulose and / or lignocellulose material flakes (30) having i) the average largest dimension selected within an interval of from 2 up to 20 mm and ii) a source roughness.41 . The bonded air-laid blank according to any one of claims 27 to 38, 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 at least 75 % by weight of cellulose and / or lignocellulose material flakes (30) having i) the average largest dimension selected within an interval of from 2 up to 20 mm and ii) a source roughness.

42. The bonded air-laid blank according to any one of claims 39 to 41 , 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.

43. The bonded air-laid blank according to any one of claims 39 to 42, wherein the recycled postindustrial and / or post-consumer cellulose and / or lignocellulose material comprises Kraft liner material.

44. The bonded air-laid blank according to any one of claims 27 to 43, wherein the polymer binder fibers are thermoplastic polymer fibers.

45. The bonded air-laid blank according to claim 44, 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.

46. The bonded air-laid blank according to any one of claims 27 to 45, wherein the polymer binder fibers are 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.

47. The bonded air-laid blank according to any one of claims 27 to 46, wherein the polymer binder fibers have an average length of less than 15 mm, preferably less than 12.5 mm and more preferably less than 10 mm.

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