WO2024245665A1

WO2024245665A1 - Method for dry-forming a cellulose product from cellulose fibres in a product forming unit and a product forming unit

Info

Publication number: WO2024245665A1
Application number: PCT/EP2024/061729
Authority: WO
Inventors: Olle HÖGBLOM
Original assignee: Pulpac AB
Priority date: 2023-05-29
Filing date: 2024-04-29
Publication date: 2024-12-05
Also published as: SE2350655A1

Abstract

A method and product forming unit for dry-forming a three-dimensional cellulose product from cellulose fibres. The product forming unit comprises a forming mould. The product forming unit is configured for arranging the loose and separated cellulose fibres onto three-dimensional surfaces of a plurality of three-dimensional shaping structures, where the three-dimensional surfaces have shapes corresponding to a shape of a three-dimensional pressing surface of the forming mould. The forming mould is configured for dry-forming a plurality of cellulose products into three- dimensional compressed structures in a pressing operation from the cellulose fibres. A formed stack of the plurality of three-dimensional shaping structures with the cellulose fibres arranged onto the three-dimensional surfaces is positioned in the forming mould. The stack of the three-dimensional shaping structures with the cellulose fibres is pressed and heated in the forming mould with a forming pressure and a forming temperature.

Description

METHOD FOR DRY-FORMING A CELLULOSE PRODUCT FROM CELLULOSE

FIBRES IN A PRODUCT FORMING UNIT AND A PRODUCT FORMING UNIT

TECHNICAL FIELD

The present disclosure relates to a method for dry-forming a cellulose product from cellulose fibres in a product forming unit. The disclosure further relates to a product forming unit for dry-forming a cellulose product from cellulose fibres.

BACKGROUND

Cellulose fibres are commonly used as raw material for producing or manufacturing cellulose products. Products formed of cellulose fibres can be used in many different situations where there is a need for sustainable products. A wide range of products can be produced from cellulose fibres, such as for example bottles, cups, and containers.

Product forming units are used when manufacturing cellulose products from raw materials including cellulose fibres, and traditionally cellulose products have been produced by wet-forming methods. One material commonly used for wet-forming cellulose fibre products is wet moulded pulp. Wet-formed products are generally formed by immersing a suction forming mould into a liquid or semi liquid pulp suspension or slurry comprising cellulose fibres, and when suction is applied, a body of pulp is formed with the shape of the desired product by fibre deposition onto the forming mould. With all wet-forming methods, there is a need for drying of the wet moulded product, where the drying process is a time and energy consuming part of the production. The demands on aesthetical, chemical and mechanical properties of cellulose products are increasing, and due to the properties of wet-formed cellulose products, the mechanical strength, flexibility, freedom in material thickness, and chemical properties are limited. It is also difficult in wet-forming processes to control the mechanical properties of the products with high precision. One development in the field of producing cellulose products, is dry-forming of cellulose products without using wet-forming methods. Instead of forming the cellulose products from a liquid or semi liquid pulp suspension or slurry, a cellulose structure air-formed from cellulose fibres is used. The cellulose structure is inserted into a forming mould and during the dry-forming of the cellulose products, the cellulose fibres are subjected to a high forming pressure and a high forming temperature. One difficulty with dry-forming methods is the problem with an efficient production process, where deep drawn cellulose products can be produced at high speeds with high quality. The air-forming and handling of the cellulose structure is a complicated and time consuming process when dry-forming the cellulose products, and there is a need for producing products with high finish at increased production rates. Thus, a more efficient product forming unit and method for producing high-quality cellulose products are desired, especially when forming deep drawn products.

SUMMARY

An object of the present disclosure is to provide a method for dry-forming a three- dimensional cellulose product from cellulose fibres in a product forming unit, and a product forming unit for dry-forming a cellulose product from cellulose fibres, where the previously mentioned problems are avoided. This object is at least partly achieved by the features of the independent claims. The dependent claims contain further developments of the method for dry-forming a cellulose product and the product forming unit for dry-forming a cellulose product.

The disclosure concerns a method for dry-forming three-dimensional cellulose products from cellulose fibres in a product forming unit comprising a forming mould. The method comprises the steps: providing loose and separated cellulose fibres and feeding the loose and separated cellulose fibres to a plurality of three-dimensional shaping structures each comprising a three-dimensional surface; arranging the loose and separated cellulose fibres in connection to the three-dimensional surfaces of the three-dimensional shaping structures, wherein the three-dimensional surfaces have shapes corresponding to a shape of a three-dimensional pressing surface of the forming mould; forming a stack of the plurality of three-dimensional shaping structures with the cellulose fibres arranged in connection to the three-dimensional surfaces; positioning the stack in the forming mould, and dry-forming a plurality of cellulose products into three-dimensional compressed structures in a pressing operation from the cellulose fibres, by pressing and heating the stack of three-dimensional shaping structures with the cellulose fibres in the forming mould with a forming pressure and a forming temperature.

Advantages with these features are that the three-dimensional shaping structures are enabling a more efficient method for producing high-quality cellulose products, which especially is suitable for forming deep drawn products. The three-dimensional surfaces of the three-dimensional shaping structures are defined as non-planar surfaces having three-dimensional shapes for an efficient forming of the stack. The three-dimensional surfaces have a surface configuration adapted to the configuration of the forming mould for an efficient positioning of the stack in the forming mould. The three-dimensional surfaces of the three-dimensional shaping structures may have any suitable three-dimensional configuration. Suitably, the three-dimensional surfaces have a shape corresponding to or similar to a final shape of the cellulose products formed in the forming mould. The three-dimensional surfaces of the three-dimensional shaping structures have shapes corresponding to the shape of the three-dimensional pressing surface of the forming mould for an efficient forming process. This is for example desired if deep drawn products are formed. With the expression corresponding shape is meant that the three-dimensional surfaces of the three- dimensional shaping structures and at least one three-dimensional pressing surface of the forming mould, have three-dimensional shapes that are similar in configuration, resulting in the forming of a stack that fits in the forming mould. It should be understood that the three-dimensional surfaces of the three-dimensional shaping structures and at least one three-dimensional pressing surface of the forming mould may or may not be identical, but at least arranged with corresponding three- dimensional shapes for an efficient positioning of the stack in the forming mould.

In one embodiment, the product forming unit comprises a fibre transporting unit. The method further comprises the steps: providing loose and separated cellulose fibres to the fibre transporting unit, and feeding the loose and separated cellulose fibres in the fibre transporting unit by means of a flow of air as carrying medium for the cellulose fibres to the plurality of three-dimensional shaping structures; arranging the loose and separated cellulose fibres onto the three-dimensional surfaces of the three- dimensional shaping structures by means of the flow of air for air-forming three- dimensional bodies of cellulose fibres, and forming the stack of the plurality of three- dimensional shaping structures with the cellulose fibres arranged onto to the three- dimensional surfaces. With these features, the process of forming the cellulose product can be more efficient, where the cellulose product can be produced at high speeds with high quality by shaping the three-dimensional bodies of cellulose fibres before dry-forming the cellulose products into the three-dimensional compressed structures in the forming mould. The handling of the cellulose fibres is simplified with the three-dimensional bodies of cellulose fibres, and the method is enabling the dryforming of cellulose products with high finish at high production rates.

In one embodiment, the plurality of three-dimensional shaping structures each comprises an outer surface and an inner surface. The three-dimensional surfaces are arranged as the outer surfaces and/or the inner surfaces. The three-dimensional shaping structures comprise a plurality of suction openings connecting the outer surfaces and the inner surfaces. The method further comprises the steps: arranging the loose and separated cellulose fibres onto the three-dimensional surfaces by means of the flow of air for air-forming the three-dimensional bodies of cellulose fibres, and applying a negative pressure via the suction openings for distributing the cellulose fibres onto the three-dimensional surfaces. The suction openings are enabling efficient deposition of the cellulose fibres onto the three-dimensional surfaces of the plurality of three-dimensional shaping structures, and the negative pressure applied is securing a desired distribution of the cellulose fibres. The suction openings may have any suitable shape, size and configuration. The shape and/or size of the suction openings may vary between different parts of the three-dimensional shaping structures, as well as the number of suction openings arranged in the three- dimensional shaping structures.

In one embodiment, the method further comprises the steps: providing loose and separated cellulose fibres and air-forming the loose and separated cellulose fibres into cellulose blank structures; arranging the cellulose blank structures in connection to the three-dimensional surfaces of the three-dimensional shaping structures, and forming the stack of the plurality of three-dimensional shaping structures with the cellulose blank structures arranged in connection to the three-dimensional surfaces. The air-formed cellulose blank structures are enabling an efficient formation of the stack, where the cellulose blank structures are arranged in connection to the three- dimensional surfaces of the plurality of three-dimensional shaping structures. The stack is formed by arranging the plurality of three-dimensional shaping structures with the cellulose blank structures on top of each other in a stacked configuration.

In one embodiment, the forming pressure is in the range of 1-600 MPa, preferably in the range of 1-100 MPa, more preferably in the range of 4-20 MPa, and the forming temperature is in the range of 60-300 °C, preferably in the range of 100-200 °C, more preferably in the range of 120-170 °C. These parameters are enabling an efficient forming of the cellulose products from the cellulose fibres into the three-dimensional compressed structure, where the cellulose products can be formed with a high rigidity.

In one embodiment, the method further comprises the step: dry-forming the cellulose product in the forming mould from the cellulose fibres in the pressing operation, where during dry-forming the three-dimensional shaping structures are supporting the cellulose fibres, and the cellulose fibres are integrated into the three-dimensional compressed structures. In this embodiment, the cellulose products are formed from the cellulose fibres. The cellulose fibres are compressed and integrated into the three- dimensional compressed structures during the pressing operation. The three- dimensional shaping structures are used as structural elements supporting the cellulose fibres during the pressing operation for an efficient forming of the cellulose products.

In one embodiment, the method further comprises the steps: removing the stack from the forming mould after the pressing operation; and separating the three-dimensional compressed structures from the three-dimensional shaping structures.

In one embodiment, the three-dimensional shaping structures are arranged as three- dimensional net structures or as three-dimensional perforated structures. These constructions are providing an efficient distribution of cellulose fibres onto the three- dimensional surfaces, while allowing the flow of air to pass through the three- dimensional shaping structures.

In one embodiment, the forming mould comprises a first mould part and a corresponding second mould part. The first mould part and/or the second mould part comprises the three-dimensional pressing surface. The method further comprises the steps: arranging the stack into a position between the first mould part and corresponding second mould part; applying the forming pressure by pressing the stack between the first mould part and corresponding second mould part; and applying the forming temperature onto the cellulose fibres in the forming mould. The first mould part is cooperating with the second mould part, and the first mould part and second mould part are interacting for efficiently forming the cellulose products into three-dimensional compressed structures.

The disclosure further concerns a product forming unit for dry-forming three- dimensional cellulose products from loose and separated cellulose fibres. The product forming unit comprises a forming mould. The product forming unit is configured for arranging the loose and separated cellulose fibres onto three-dimensional surfaces of a plurality of three-dimensional shaping structures, where the three-dimensional surfaces have shapes corresponding to a shape of a three-dimensional pressing surface of the forming mould. The forming mould is configured for dry-forming a plurality of cellulose products into three-dimensional compressed structures in a pressing operation from the cellulose fibres. A formed stack of the plurality of three- dimensional shaping structures with the cellulose fibres arranged onto the three- dimensional surfaces is positioned in the forming mould. The stack of the three- dimensional shaping structures with the cellulose fibres is pressed and heated in the forming mould with a forming pressure and a forming temperature.

Advantages with these features are that the three-dimensional shaping structures are enabling a more efficient product forming unit for producing high-quality cellulose products, which especially is suitable for forming deep drawn products. The three- dimensional surfaces of the three-dimensional shaping structures are defined as non- planar surfaces having three-dimensional shapes for an efficient forming of the stack. The three-dimensional surfaces have a surface configuration adapted to the configuration of the forming mould for an efficient positioning of the stack in the forming mould. The three-dimensional surfaces of the three-dimensional shaping structures may have any suitable three-dimensional configuration. Suitably, the three- dimensional surfaces have a shape corresponding to or similar to a final shape of the cellulose products formed in the forming mould. The three-dimensional surfaces of the three-dimensional shaping structures have shapes corresponding to the shape of the three-dimensional pressing surface of the forming mould for an efficient forming process. This is for example desired if deep drawn products are formed. With the expression corresponding shape is meant that the three-dimensional surfaces of the three-dimensional shaping structures and at least one three-dimensional pressing surface of the forming mould, have three-dimensional shapes that are similar in configuration, resulting in the forming of a stack that fits in the forming mould. It should be understood that the three-dimensional surfaces of the three-dimensional shaping structures and at least one three-dimensional pressing surface of the forming mould may or may not be identical, but at least arranged with corresponding three- dimensional shapes for an efficient positioning of the stack in the forming mould.

In one embodiment, the product forming unit further comprises a fibre transporting unit. The fibre transporting unit is configured for feeding loose and separated cellulose fibres from the fibre transporting unit to the three-dimensional shaping structures by means of a flow of air as carrying medium for the cellulose fibres. The loose and separated cellulose fibres are arranged onto three-dimensional surfaces of the three- dimensional shaping structures by means of the flow of air for air-forming three- dimensional bodies of cellulose fibres. The stack is formed of the plurality of three- dimensional shaping structures with the cellulose fibres arranged onto to the three- dimensional surfaces. With these features, the product forming unit can be more efficient, where the cellulose product are produced at high speeds with high quality by shaping the three-dimensional bodies of cellulose fibres before dry-forming the cellulose products into the three-dimensional compressed structures in the forming mould. The handling of the cellulose fibres is simplified with the three-dimensional bodies of cellulose fibres, and the method is enabling the dry-forming of cellulose products with high finish at high production rates.

In one embodiment, the three-dimensional shaping structures each comprises an outer surface and an inner surface. The three-dimensional surfaces are arranged as the outer surfaces and/or the inner surfaces. The three-dimensional shaping structures comprise a plurality of suction openings connecting the outer surfaces and the inner surfaces. The suction openings are enabling efficient deposition of the cellulose fibres onto the three-dimensional surfaces, and when applying a negative pressure a desired distribution of the cellulose fibres is enabled. The suction openings may have any suitable shape, size and configuration. The shape and/or size of the suction openings may vary between different parts of the three-dimensional shaping structures, as well as the number of suction openings arranged in the three- dimensional shaping structures.

In one embodiment, the stack is formed of the plurality of three-dimensional shaping structures with cellulose blank structures arranged in connection to the three- dimensional surfaces. The loose and separated cellulose fibres are air-formed into the cellulose blank structures. The air-formed cellulose blank structures are enabling an efficient formation of the stack, where the cellulose blank structures are arranged in connection to the three-dimensional surfaces of the plurality of three-dimensional shaping structures. The stack is formed by arranging the plurality of three-dimensional shaping structures with the cellulose blank structures on top of each other in a stacked configuration.

In one embodiment, the forming pressure is in the range of 1-600 MPa, preferably in the range of 1-100 MPa, more preferably in the range of 4-20 MPa, and the forming temperature is in the range of 60-300 °C, preferably in the range of 100-200 °C, more preferably in the range of 120-170 °C. These parameters are enabling an efficient forming of the cellulose products into the three-dimensional compressed structures, where the cellulose products can be formed with a high rigidity.

In one embodiment, the forming mould is configured for dry-forming the cellulose products from the cellulose fibres in the pressing operation. The three-dimensional shaping structures are configured for supporting the cellulose fibres, and the cellulose fibres are integrated into the three-dimensional compressed structures. In this embodiment, the cellulose products are formed from the cellulose fibres. The cellulose fibres are compressed and integrated into the three-dimensional compressed structures during the pressing operation. The three-dimensional shaping structures are used as structural elements supporting the cellulose fibres during the pressing operation for an efficient forming of the cellulose products.

In one embodiment, the three-dimensional shaping structures are arranged as three- dimensional net structures or as three-dimensional perforated structures. These constructions are providing an efficient distribution of cellulose fibres onto the three- dimensional surfaces, while allowing the flow of air to pass through the three- dimensional shaping structures. In one embodiment, the forming mould comprises a first mould part and a corresponding second mould part. The first mould part and/or the second mould part comprises the three-dimensional pressing surface. The forming mould is configured for applying the forming pressure by pressing the stack between the first mould part and corresponding second mould part. The forming mould is configured for applying the forming temperature onto the cellulose fibres. The first mould part is cooperating with the second mould part, and the first mould part and second mould part are interacting for efficiently forming the cellulose products into the three-dimensional compressed structures.

BRIEF DESCRIPTION OF DRAWINGS

The disclosure will be described in detail in the following, with reference to the attached drawings, in which

Fig. 1a-f show schematically, in side views, an embodiment of a product forming unit for dry-forming cellulose products, where the product forming unit comprises a fibre transporting unit and a forming mould, and where a stack of three-dimensional shaping structures and three-dimensional bodies of cellulose fibres is used during a pressing operation in the forming mould,

Fig. 2a-b show schematically, in perspective views from above, a three- dimensional shaping structure and an alternative embodiment of the three-dimensional shaping structure, and

Fig. 3a-c show schematically, in perspective views, forming of a stack of three- dimensional shaping structures and cellulose blank structures, and in a side view, an alternative embodiment of a product forming unit for dryforming cellulose products, where the product forming unit comprises a forming mould, and where the stack is used during a pressing operation in the forming mould.

Fig. 4 show schematically, in side views, an embodiment of a product forming unit for dry-forming cellulose products, where the product forming unit comprises a fibre transporting unit and a forming mould, and where a stack of a multitude of three-dimensional shaping structures and three- dimensional bodies of cellulose fibres is used during a pressing operation in the forming mould.

DESCRIPTION OF EXAMPLE EMBODIMENTS

Various aspects of the disclosure will hereinafter be described in conjunction with the appended drawings to illustrate and not to limit the disclosure, wherein like designations denote like elements, and variations of the described aspects are not restricted to the specifically shown embodiments, but are applicable on other variations of the disclosure.

In the figures, different embodiments of a product forming unit II are schematically illustrated, in which a cellulose product 1 is dry-formed from cellulose fibres CF. The product forming unit II comprises a forming mould M. Loose and separated cellulose fibres CF are provided and fed to a plurality of three-dimensional shaping structures S. The loose and separated cellulose fibres CF are arranged in connection to three- dimensional surfaces SSD of the three-dimensional shaping structures S, and the three-dimensional surfaces SSD have shapes corresponding to a shape of a three- dimensional pressing surface SPSD of the forming mould M. A stack X is formed from the plurality of three-dimensional shaping structures S with the cellulose fibres CF arranged in connection to the three-dimensional surfaces SSD. The stack X is thereafter positioned in the forming mould M, and the cellulose products 1 are dry- formed into three-dimensional compressed structures CSD in a pressing operation OP from the cellulose fibres CF. The cellulose products 1 are dry-formed in the forming mould M, by pressing and heating the stack X of three-dimensional shaping structures S with the cellulose fibres CF with a forming pressure Pp and a forming temperature T_F.

By a plurality of three-dimensional shaping structures S, is meant that two or more three-dimensional shaping structures S are used for forming the stack X.

With the expression cellulose product 1 is meant a product that is dry-formed in the forming mould M from the cellulose fibres CF. The dry-formed cellulose product 1 may be a final product ready for use in a specific application. Alternatively, the dry-formed cellulose product 1 may be a pre-formed part of a final product and thus constitute a part of an assembled final product. One or more pre-formed parts may for example be attached to each other with glue or other fastening means into a final product.

With the expression loose and separated cellulose fibres CF is meant cellulose fibres that are separated from each other and loosely arranged relative to each other, or cellulose fibres or cellulose fibre bundles that are separated from each other and loosely arranged relative to each other.

The cellulose fibres CF may originate from a suitable cellulose raw material, such as a pulp material. Suitable pulp materials are for example fluff pulp, paper structures, or other cellulose fibre containing structures. The cellulose fibres may also be extracted from agricultural waste materials, for example wheat straws, fruit and vegetable peels, bagasse, or from other suitable sources. When for example using pulp as raw material for the cellulose fibres CF, the pulp structure commonly needs to be separated in a separating unit, such as a suitable mill unit. In the separating unit, the pulp structure is separated into individual cellulose fibres, or into individual cellulose fibres and cellulose fibre bundles, and the better milling process the more individual cellulose fibres are formed. In other embodiments, only individual cellulose fibres may be used as raw material. The loose and separated cellulose fibres CF may be provided by a mill unit arranged in connection to the product forming unit II, or alternatively preprepared loose and separated cellulose fibres CF are provided to the product forming unit II.

The three-dimensional surface SSD of each three-dimensional shaping structure S is defined as a non-planar surface having a three-dimensional shape for an efficient forming operation in the forming mould M. The three-dimensional surface SSD of the three-dimensional shaping structure S has a surface configuration adapted to the configuration of the forming mould M for an efficient positioning of the stack X in the forming mould M. The three-dimensional surface SSD of the three-dimensional shaping structure S may have any suitable three-dimensional configuration, and the three- dimensional surface SSD may for example be arranged with elevated, undulating, rounded and/or step-like surface sections. Suitably, the three-dimensional surface SSD of the three-dimensional shaping structure S has a shape corresponding to or similar to a final shape of the cellulose product 1 formed in the forming mould M. The cellulose fibres CF may have a composition where the fibres are of the same origin or alternatively contain a mix of two or more types of cellulose fibres, depending on the desired properties of the cellulose products 1. The cellulose fibres CF are during the forming process of the cellulose products 1 strongly bonded to each other. The loose and separated cellulose fibres CF may be mixed with other substances or compounds to a certain amount, and specifically an amount of at least 95% cellulose fibres, or more specifically at least 99% cellulose fibres, may be used. However, the cellulose fibres CF may have other suitable configurations and cellulose fibre amounts. With cellulose fibres is meant any type of cellulose fibres, such as natural cellulose fibres or manufactured cellulose fibres.

The three-dimensional surfaces SSD of the three-dimensional shaping structures S have shapes corresponding to a shape of a three-dimensional pressing surface SPSD of the forming mould M. When positioning the stack X in the forming mould M, the cellulose products 1 can be dry-formed into three-dimensional compressed structures CSD in the pressing operation OP by pressing and heating the stack X in the forming mould M with the forming pressure Pp and the forming temperature Tp.

The forming mould M is thus used for dry-forming the cellulose products 1 into three- dimensional compressed structures CSD, by pressing and heating the stack X formed from the plurality of three-dimensional dimensional shaping structures S with the cellulose fibres CF in the forming mould M with a forming pressure Pp in the range of 1-600 MPa, preferably in the range of 1-100 MPa, more preferably in the range of 4- 20 MPa, and a forming temperature Tp in the range of 60-300 °C, preferably in the range of 100-200 °C, more preferably in the range of 120-170 °C. The forming pressure Pp may selectively be higher in specific parts or areas of the forming mould M. This higher forming pressure Pp may be used for forming sections of the cellulose products 1 having a higher stiffness.

Figures 1a-f schematically show an embodiment of a product forming unit II in which cellulose products 1 are dry-formed from cellulose fibres CF. The product forming unit II comprises a fibre transporting unit T and a forming mould M.

The product forming unit II further comprises a support structure 11 arranged in connection to the fibre transporting unit T. The fibre transporting unit T is used for feeding loose and separated cellulose fibres CF into a flow of air A, and for transporting the cellulose fibres CF to the three-dimensional shaping structures S by means of the flow of air A as carrying medium for the cellulose fibres CF. The support structure 11 is used for holding the three-dimensional shaping structures S for forming three-dimensional bodies B of cellulose fibres CF onto the three-dimensional shaping structures S from the cellulose fibres CF transported by the flow of air. The loose and separated cellulose fibres are arranged onto the three-dimensional surfaces SSD of the three-dimensional shaping structures S by means of the flow of air A.

The fibre transporting unit T is used for arranging the loose and separated cellulose fibres CF onto the three-dimensional surfaces SSD of the three-dimensional shaping structures S by means of the flow of air A for air-forming the three-dimensional bodies B of cellulose fibres CF. In this way, the three-dimensional bodies B of cellulose fibres CF are air-formed in a dry and controlled fibre forming process in which the cellulose fibres CF are air-formed onto the three-dimensional surfaces SSD of the three- dimensional shaping structures S by means of the flow of air A as carrying medium for the cellulose fibres CF. It should be understood that even if the three-dimensional bodies B of cellulose fibres CF are slightly compacted before the forming of the cellulose products 1 , such as compacting the three-dimensional bodies B for feeding or transportation purposes, the three-dimensional bodies B still comprise loose and separated cellulose fibres CF.

With an air-formed three-dimensional body B of cellulose fibres CF is meant an essentially air-formed fibrous structure produced from cellulose fibres CF, where cellulose fibres CF are carried and formed to the three-dimensional body B of cellulose fibres CF by air as carrying medium. This is different from a normal papermaking process or a traditional wet-forming process, where water is used as carrying medium for the cellulose fibres when forming the paper or fibre structure. In the air-forming process, small amounts of water or other substances may if desired be added to the cellulose fibres in order to change the properties of the cellulose products, but air is still used as carrying medium in the forming process. The small amount of water has the advantage of enabling forming of hydrogen bonds between the fibres in the forming mould when subjected to pressure and temperature. The hydrogen bonds are an important factor for rigidity of the cellulose product.

As described above, the loose and separated cellulose fibres are arranged onto the three-dimensional surfaces SSD of the three-dimensional shaping structures S by means of the flow of air A for air-forming the three-dimensional bodies B of cellulose fibres CF. The three-dimensional surfaces SSD of the three-dimensional shaping structures S are in this way defining the three-dimensional shape of the three- dimensional bodies B of cellulose fibres CF. Suitably, the three-dimensional shaping structures S are arranged as three-dimensional net structures or as three-dimensional perforated structures that are made of a relatively stiff material for an efficient airforming of the three-dimensional bodies B of cellulose fibres CF onto the three- dimensional surfaces SSD, and for efficient transport of the air-formed three- dimensional bodies B of cellulose fibres CF together with the three-dimensional shaping structures S from the fibre transporting unit T to the forming mould M. Suitable material configurations for the three-dimensional shaping structure S are for example three-dimensional steel structures, three-dimensional aluminium structures, three- dimensional plastic structures, or three-dimensional composite structures.

An exemplified three-dimensional shaping structure S is illustrated in figure 2a, and the three-dimensional shaping structure S comprises a three-dimensional surface SSD. A three-dimensional body B of cellulose fibres CF is formed onto the three- dimensional surface SSD from the cellulose fibres CF transported by the flow of air A to three-dimensional shaping structure S, as will be further described below. The three-dimensional shaping structure S may have any suitable three-dimensional shape and configuration, such as for example shapes with male and/or female configurations.

In figure 2a, a three-dimensional shaping structure S with a male configuration is schematically illustrated, and in figure 2b, an alternative embodiment of a three- dimensional shaping structure S with a female configuration is schematically illustrated.

In the embodiment shown in figures 1 a-f , the fibre transporting unit T comprises a flow channel 8 in which a flow of air A is introduced, for example by a suitable fan unit or other air flow establishing device of the fibre transporting unit T. The three- dimensional shaping structures S are arranged in connection to the flow channel 8 upon forming of the three-dimensional body B of cellulose fibres CF to enable the distribution of cellulose fibres CF onto the three-dimensional surfaces SSD. The fibre transporting unit T comprises a fibre outlet TFO, and the fibre outlet TFO is suitably arranged in connection to the flow channel 8. The fibre outlet TFO may be configured as a hood H or similar arrangement, for an efficient distribution of cellulose fibres CF onto the three-dimensional shaping structures S. Loose and separated cellulose fibres CF are introduced into the flow of air A for forming a mix of air and cellulose fibres CF that are transported by means of the flow of air A in the flow channel 8. The loose and separated cellulose fibres CF are in this way fed in the fibre transporting unit T by means of a flow of air A to the fibre outlet T FO of the fibre transporting unit T.

In other non-illustrated embodiments, two or more flow channels 8 may be arranged in connection to the support structure 11 , for feeding different types of cellulose fibres CF to the three-dimensional shaping structure S. In this way, air-forming of the three- dimensional body B of cellulose fibres CF with layers of different cellulose fibres CF is enabled.

In some embodiments, a non-illustrated mill unit may be arranged in connection to the flow channel 8. The mill unit may be used for both separating cellulose raw material into loose and separated cellulose fibres CF and establishing the flow of air A in the flow channel 8. A mix of cellulose fibres CF into the flow of air A may be established directly by the mill unit.

As indicated in figures 1a-f, the fibre transporting unit T is feeding the loose and separated cellulose fibres CF in the flow channel 8 to the three-dimensional surfaces SSD of the three-dimensional shaping structures S by means of the flow of air A.

As shown in for example figure 2a, the three-dimensional shaping structures S comprise an outer surface So and an inner surface Si. The inner surface Si is arranged opposite the outer surface So.

In the embodiment shown in figure 2a, a plurality of suction openings 7 are connecting the outer surface So and the inner surface Si. In this embodiment, the three- dimensional surface SSD is arranged as the outer surface So of the three-dimensional shaping structure S. The three-dimensional surface SSD of the three-dimensional shaping structure S is configured for receiving the loose and separated cellulose fibres CF by means of the flow of air A for forming the three-dimensional body B of cellulose fibres CF upon application of a negative pressure PN via the suction openings 7 for distributing the cellulose fibres CF onto the three-dimensional surface SSD, as schematically illustrated in figure 1 b. The three-dimensional shaping structure S may suitably be arranged as a three-dimensional net structure or as a solid perforated structure, as described above. The suction openings 7 may have any suitable shape, size and configuration. The shape and/or size of the suction openings 7 may vary between different parts of the three-dimensional shaping structure S, as well as the number of suction openings 7 arranged in the three-dimensional shaping structure S.

In other non-illustrated embodiments, the three-dimensional shaping structures S are only partly arranged with suction openings 7 for steering and controlling the flow of cellulose fibres CF.

In further non-illustrated embodiments, the three-dimensional shaping structures S may be arranged without the suction openings, and the cellulose fibres CF are deposited onto the three-dimensional surface SSD without the need for applying a negative pressure through the three-dimensional shaping structures S. In this way, the cellulose fibres CF are instead shot or sprayed onto the three-dimensional surface SSD by a flow of air A as carrying medium for the cellulose fibres CF.

In further non-illustrated embodiments, the three-dimensional surface SSD is instead arranged as the inner surface Si of the three-dimensional shaping structures S. Alternatively, the three-dimensional surface SSD may be arranged fully or partly as the outer surface So and the inner surface Si of the three-dimensional shaping structures S, or the three-dimensional surface SSD may be arranged as one or more parts of the outer surface So and/or the inner surface Si of the three-dimensional shaping structures S.

The forming of the three-dimensional body B of cellulose fibres CF is sequentially illustrated in figures 1a-f. In figure 1a, a provided first three-dimensional shaping structure Si is transported to the fibre transporting unit T, as indicated with the arrow. Thereafter, the provided first three-dimensional shaping structure Si is arranged on the support structure 11 in connection to the to the fibre outlet TFO of the fibre transporting unit T, into a position in which cellulose fibres CF can be deposited onto the first three-dimensional shaping structure Si, as shown in figure 1b. In the illustrated embodiment, the support structure 11 is configured as a stationary support structure, and the three-dimensional shaping structure S is transported to the position in figure 1b with any suitable transportation means. In this position, the three- dimensional shaping structure S is initially empty and ready for receiving cellulose fibres CF from the fibre transporting unit T. The fibre transporting unit T is suitably movably arranged, and the hood H with the fibre outlet TFO may in this way be positioned over the three-dimensional shaping structure S, as understood from the figure.

In other non-illustrated embodiments, the support structure 11 may instead be arranged as a movable support structure. The movable support structure may be configured as an endless circulating support structure having a belt-like configuration. The three-dimensional shaping structures S are transported to the fibre outlet TFO, by means of the movable support structure.

When the first three-dimensional shaping structure Si is arranged in connection to the fibre outlet TFO of the fibre transporting unit T, as shown in figure 1 b, the loose and separated cellulose fibres CF are deposited onto the three-dimensional surface SSD of the first three-dimensional shaping structure Si by means of the flow of air A for airforming a three-dimensional body B of cellulose fibres CF.

In the position shown in figure 1b, the first three-dimensional shaping structure Si is arranged in direct connection to the fibre outlet TFO, and the loose and separated cellulose fibres CF transported in the fibre transporting unit T are deposited onto the three-dimensional surface SSD. The loose and separated cellulose fibres CF are fed from the fibre outlet TFO to the first three-dimensional shaping structure Si by means of the flow of air A as carrying medium for the cellulose fibres CF, and the three- dimensional body B of cellulose fibres CF is built up on the three-dimensional surface SSD. The three-dimensional surface SSD of the first three-dimensional shaping structure Si is suitably receiving the loose and separated cellulose fibres CF by means of the flow of air A for forming the three-dimensional body B of cellulose fibres CF by applying a negative pressure PN via the suction openings 7 for distributing the cellulose fibres CF onto the three-dimensional surface SSD.

The three-dimensional body B of cellulose fibres CF is air-formed in a dry and controlled fibre forming process in which the cellulose fibres CF are deposited onto the three-dimensional surface SSD of the first three-dimensional shaping structure Si by means of the flow of air A as carrying medium for the cellulose fibres CF when the first three-dimensional shaping structure Si is arranged in connection to the fibre outlet TFO, as shown in figure 1 b. When a suitable amount of cellulose fibres CF are formed onto the three-dimensional surface SSD, the three-dimensional body B of cellulose fibres CF is formed, and thereafter the first three-dimensional shaping structure Si with the formed three-dimensional body B of cellulose fibres CF can be further transported into a stacking position PST, as indicated with the arrow in figure 1c.

As understood from figure 1c, when the first three-dimensional shaping structure Si is transported away from the support structure 11 , a provided second three- dimensional shaping structure S2 may be transported to the fibre transporting unit T. The second three-dimensional shaping structure S2 is arranged on the support structure 11 in connection to the to the fibre outlet TFO of the fibre transporting unit T, into a position in which cellulose fibres CF can be deposited onto the second three- dimensional shaping structure S2, as shown in figure 1c.

After forming a three-dimensional body B of cellulose fibres CF onto the second three- dimensional shaping structure S2, the second three-dimensional shaping structure S2 with the formed three-dimensional body B of cellulose fibres CF can be further transported into the stacking position PST, as shown in figure 1d. In this way, a stack X is formed from a plurality of three-dimensional shaping structures S with the cellulose fibres CF arranged in connection to the three-dimensional surfaces SSD. In figure 1d, a stack X of four three-dimensional shaping structures S with the cellulose fibres CF arranged in connection to the three-dimensional surfaces SSD is schematically illustrated.

The stack X may have two or more three-dimensional shaping structures S with cellulose fibres CF arranged in connection to the three-dimensional surfaces SSD arranged on top of each other in a stacked configuration.

In the illustrated example shown in figure 1 d, the stack X is formed by the first three- dimensional shaping structure Si with cellulose fibres CF arranged in connection to the three-dimensional surface SSD, the second three-dimensional shaping structure S2 with cellulose fibres CF arranged in connection to the three-dimensional surface SSD, a third three-dimensional shaping structures S3 with cellulose fibres CF arranged in connection to the three-dimensional surface SSD, and a fourth three-dimensional shaping structures S4 with cellulose fibres CF arranged in connection to the three- dimensional surface SSD. The stack X is thereafter positioned in the forming mould M, as shown in figure 1e. The cellulose products 1 are dry-formed into three-dimensional compressed structures CSD in a pressing operation OP from the cellulose fibres CF. With the configuration of the stack X exemplified above, four cellulose products 1 can be formed simultaneously in the forming mould M during the pressing operation OP. The cellulose products 1 are dry-formed in the forming mould M, by pressing and heating the stack X of three-dimensional shaping structures S with the cellulose fibres CF with a forming pressure Pp and a forming temperature Tp.

The three-dimensional shaping structures S suitably have configurations that enables efficient forming of the stack X. The geometries of the outer surface So and the inner surface Si of the three-dimensional shaping structures S may be different in order to achieve a stack X where two or more three-dimensional shaping structures S can be positioned on top of each other without any gaps between two adjacent three- dimensional shaping structures S, or with only minor gaps between two adjacent three-dimensional shaping structures S. Such a configuration with cooperating surfaces is enabling an efficient forming of the cellulose products 1 from the cellulose fibres CF in the forming mould M, where the three-dimensional compressed structures CSD have uniform thickness. In other embodiments, the geometries of the outer surfaces So and the inner surfaces Si of the three-dimensional shaping structures S are designed for enabling a varied thickness of the three-dimensional compressed structures CSD, and in this way cellulose products 1 with areas or sections having a higher thickness can be produced.

The forming mould M comprises a first mould part 3a and a corresponding second mould part 3b that are cooperating for forming the cellulose products 1 from the three- dimensional bodies B of cellulose fibres CF in the stack X. The first mould part 3a and the second mould part 3b are movably arranged relative to each other, and the first mould part 3a and the second mould part 3b are configured for moving relative to each other in a pressing direction Dp.

In the embodiment shown in figures 1 a-f, the second mould part 3b is stationary and the first mould part 3a is movably arranged in relation to the second mould part 3b in the pressing direction DP, during the pressing operation OP. AS indicated with the double arrow in figure 1a, the first mould part 3a is configured to move both towards the second mould part 3b and away from the second mould part 3b in linear movements along an axis extending in the pressing direction Dp.

It should be understood that for all embodiments according to the disclosure, the expression moving in the pressing direction DP includes a movement in the pressing direction DP, and the movement may take place in opposite directions. The expression may further include both linear and non-linear movements of a mould part, where the result of the movement during forming is a repositioning of the mould part in the pressing direction Dp.

The first mould part 3a, the second mould part 3b, and the three-dimensional surfaces SSD of the three-dimensional shaping structures S are in the embodiment shown in figures 1a-f used for pressing the three-dimensional bodies B of cellulose fibres CF. The three-dimensional surface SSD of each three-dimensional shaping structures S has a shape corresponding to a shape of a three-dimensional pressing surface SPSD of the forming mould M. In this embodiment, the first mould part 3a comprises the three-dimensional pressing surface SPSD. Thus, the three-dimensional surface SSD of the three-dimensional shaping structure S has a shape corresponding to the shape of a three-dimensional pressing surface SPSD of the first mould part 3a. As described above, the three-dimensional surface SSD is an outer surface So of the three- dimensional shaping structures S, and the three-dimensional surface SSD is arranged as a pressing surface for an efficient forming of the cellulose product 1 .

In the shown embodiment, the three-dimensional pressing surface SPSD of the first mould part 3a and the three-dimensional surface SSD of the uppermost three- dimensional shaping structure S in the stack X are configured as cooperating pressing surfaces during the pressing operation OP. The geometry of the three-dimensional pressing surface SPSD may be the same as or similar to the geometry of the inner surface Si of the three-dimensional shaping structures S. The inner surface Si of an upper three-dimensional shaping structure S is configured as a pressing surface that is cooperating with an outer surface So of a direct adjacent lower three-dimensional shaping structure S.

When the stack X is positioned in the forming mould M, as illustrated in figure 1e, the three-dimensional pressing surface SPSD of the first mould part 3a and the outer surface of the fourth three-dimensional shaping structure S4 are configured as cooperating pressing surfaces during the pressing operation OP in the forming mould M. The inner surface of the fourth three-dimensional shaping structure S4 and the outer surface of the third three-dimensional shaping structure S3 are configured as cooperating pressing surfaces during the pressing operation OP in the forming mould M. The inner surface of the third three-dimensional shaping structure S3 and the outer surface of the second three-dimensional shaping structure S2 are configured as cooperating pressing surfaces during the pressing operation OP in the forming mould M. The inner surface of the second three-dimensional shaping structure S2 and the outer surface of the first three-dimensional shaping structure Si are configured as cooperating pressing surfaces during the pressing operation OP in the forming mould M.

The three-dimensional pressing surface SPSD of the first mould part 3a is further configured as a pressing surface arranged to press the three-dimensional shaping structures S and the formed three-dimensional bodies B of cellulose fibres OF during the pressing operation OP, when the stack X is arranged between the first mould part 3a and the second mould part 3b. The stack X is in this way during the pressing operation OP in the forming mould M pressed between the first mould part 3a and the second mould part 3b, for forming a plurality of cellulose products 1 simultaneously from the three-dimensional bodies B of cellulose fibres OF.

By arranging the three-dimensional surfaces S3D of the three-dimensional shaping structures S and the three-dimensional pressing surface SPSD of the first mould part 3a with corresponding shapes, an efficient cellulose product forming process is achieved. This is for example desired if deep drawn products are formed.

With the expression corresponding shape is meant that the three-dimensional surfaces S3D of the three-dimensional shaping structures S and the three-dimensional pressing surface SPSD of the forming mould M, such as the surface in the first mould part 3a, have three-dimensional shapes that are similar in configuration, resulting in the forming of a stack X that fits in the forming mould M. It should be understood that the three-dimensional surfaces S3D of the three-dimensional shaping structures S and the three-dimensional pressing surface SPSD of the forming mould M may or may not be identical, but at least arranged with corresponding three-dimensional shapes for an efficient pressing geometry when the stack X is positioned in the forming mould M. In the embodiment shown in figures 1a-f, the second mould part 3b comprises a receiving surface 9 arranged for holding the stack X. As shown in figures 1d-e, the stack X is positioned onto the receiving surface 9 of the second mould part 3b. The receiving surface 9 is configured for supporting the stack X during the pressing operation OP.

In other non-illustrated embodiments, the second mould part 3b instead comprises the three-dimensional pressing surface SPSD, and the first mould part 3a may then comprise a receiving surface 9 arranged for supporting the stack X.

The forming mould M is configured for dry-forming the cellulose products 1 into three- dimensional compressed structures CSD in a pressing operation OP from the three- dimensional bodies B of cellulose fibres OF, by pressing and heating the stack X of three-dimensional shaping structures S with the three-dimensional bodies B of cellulose fibres OF with a forming pressure Pp and a forming temperature Tp, between the first mould part 3a and the second mould part 3b. The forming mould M is applying the forming pressure Pp by pressing the stack X between the first mould part 3a and the second mould part 3b, as shown in figure 1e. The forming mould M is further applying the forming temperature Tp onto the air-formed three-dimensional bodies B of cellulose fibres CF.

When the three-dimensional body B of cellulose fibres CF is formed with a shape corresponding to the shape of the first mould part 3a and the three-dimensional shaping structure S, as shown in figures 1a-f, the dry-forming operation in the forming mould M can be made with reduced risks of weak material sections and/or cracks in the final cellulose product 1 , since the three-dimensional bodies B of cellulose fibres CF will not be stretched out a major extent during the pressing operation OP in the forming mould M.

With the expression pressing operation OP is meant the operation of the mould parts for forming a cellulose product 1 from the three-dimensional bodies B of cellulose fibres CF. In the embodiment shown in figures 1 a-f, the pressing operation OP starts when the first mould part 3a is moved from a stationary position. In this position, the first mould part 3a and the second mould part 3b are arranged at a distance from each other and the stack X can be fed into the forming mould M in a forming position between the first mould part 3a and the second mould part 3b, as illustrated in figures 1d-e.

When the cellulose products 1 have been formed in the forming mould M, the first mould part 3a is moved away from the second mould part 3b back to the stationary position, as understood from figures 1e-f. When the first mould part 3a has reached the stationary position again, the pressing operation OP is completed. The pressing operation OP is thus defined as a pressing cycle during which the three-dimensional shaping structures S with the three-dimensional bodies B of cellulose fibres OF in the stack X are exerted to the forming pressure P_F, and the duration of the pressing operation OP is suitably calculated from the start of the movement of the first mould part 3a from the stationary position until the first mould part 3a has reached the stationary position again.

The forming mould M is configured for dry-forming the cellulose products 1 from the three-dimensional bodies B of cellulose fibres OF in the pressing operation OP, and the three-dimensional shaping structures S are supporting the three-dimensional bodies B of cellulose fibres CF during the pressing operation OP. The forming mould M is in the pressing operation OP dry-forming the cellulose products 1 into three- dimensional compressed structures CSD by pressing and heating the three- dimensional bodies B of cellulose fibres CF in the forming mould M with a forming pressure P_F in the range of 1-600 MPa, preferably in the range of 1-100 MPa, more preferably in the range of 4-20 MPa, and a forming temperature T_F in the range of 60- 300 °C, preferably in the range of 100-200 °C, more preferably in the range of 120- 170 °C. In this way, the cellulose fibres CF in the three-dimensional bodies B of cellulose fibres CF are integrated into the three-dimensional compressed structures C3D.

The forming pressure P_F may selectively be higher in specific parts or areas of the forming mould M. This higher forming pressure P_F may be used for forming sections of the cellulose products 1 having a higher stiffness.

The three-dimensional bodies B of cellulose fibres CF may be compacted before dryforming the cellulose products 1 in the forming mould M. The compacting operation is compressing the fibre structure of the three-dimensional bodies B of cellulose fibres CF into a more dense structure, without influencing the general three-dimensional shape.

The forming mould M may further comprise a heating unit. The heating unit is configured for applying the forming temperature TF onto the three-dimensional bodies B of cellulose fibres CF during the forming operation in the forming mould M. The heating unit may have any suitable configuration. The heating unit may be integrated in or cast into the first mould part 3a and/or second mould part 3b, and suitable heating devices are e.g. electrical heaters, such as resistor elements, or fluid heaters. Other suitable heat sources may also be used.

The forming pressure PF may be applied to the three-dimensional bodies B of cellulose fibres CF in only one pressing step during the pressing operation OP. Suitably, the cellulose products 1 are dry-formed into the three-dimensional compressed structures CSD in a single pressing operation by pressing and heating the three-dimensional bodies B of cellulose fibres CF in the forming mould M with the forming pressure PF and the forming temperature TF. In this way, the forming pressure PF and the forming temperature TF are applied onto the three-dimensional bodies B of cellulose fibres CF during a single pressing operation upon forming of the cellulose products 1 in the forming mould M. With a single pressing operation is meant that the cellulose products 1 are formed from the three-dimensional bodies B of cellulose fibres CF in one single pressing step in the forming mould M. In the single pressing operation, the first mould part 3a and the second mould part 3b are interacting with each other for establishing the forming pressure PF and the forming temperature TF during a single operational engagement step. Thus, in the single pressing operation, the forming pressure PF and the forming temperature TF are not applied to the three- dimensional bodies B of cellulose fibres CF in two or more repeated pressing steps.

Alternatively, the forming pressure PF may be applied in two or more repeated pressing steps during the pressing operation OP, and in this way, the mould parts are repeatedly exerting the forming pressure PF onto the three-dimensional bodies B of cellulose fibres CF.

After the pressing operation OP in the forming mould M, the stack X comprising the formed three-dimensional compressed structures CSD and the three-dimensional shaping structures S are removed from the forming mould M, and the three- dimensional compressed structures CSD are separated from the three-dimensional shaping structures S, as illustrated in figure 1f. The shaping structures S may thereafter be reused.

It should be understood that the forming mould M may have other configurations. In alternative non-illustrated embodiments, the first mould part 3a may be stationary and the second mould part 3b movably arranged in relation to the first mould part 3a during the pressing operation OP, or both the first mould part 3a and the second mould part 3b are movably arranged towards and away from each other.

The forming mould M may have a single-cavity configuration with one first mould part 3a and one second mould part 3b cooperating with each other for dry-forming the cellulose products 1 , as shown in figures 1a-f.

Alternatively, the forming mould M may have a multi-cavity configuration, where instead two or more first mould parts 3a are cooperating with two or more corresponding second mould parts 3b. In this way, two or more stacks X can be handled in one pressing operation OP. A single-cavity configuration forming mould M thus comprises only one first mould part 3a and a cooperating second mould part 3b. A multi-cavity configuration forming mould M comprises two or more cooperating first mould parts 3a and second mould parts 3b.

It should be understood that even if the forming mould M is described in connection to a single-cavity configuration forming mould, the disclosure is equally applicable on multi-cavity configuration forming moulds.

In an alternative embodiment shown in figures 3a-c, cellulose blank structures 2 comprising loose and separated cellulose fibres CF are used for forming the cellulose products 1 into three-dimensional compressed structures CSD. In this embodiment, the cellulose blank structures 2 are used instead of the three-dimensional cellulose bodies B of cellulose fibres CF. The product forming unit II comprises a forming mould M, as shown in figure 3c.

The cellulose blank structures 2 are air-formed from the cellulose fibres CF. With an air-formed cellulose blank structure 2 is meant an essentially air-formed fibrous web structure produced from cellulose fibres CF, where the cellulose fibres CF are carried and formed to the cellulose blank structure 2 by air as carrying medium. The cellulose blank structure 2 comprises loose and separated cellulose fibres CF that are compressed upon forming of the cellulose products 1. With loose and separated cellulose fibres is meant cellulose fibres that are separated from each other and loosely arranged relative to each other within the cellulose blank structure 2, or cellulose fibres or cellulose fibre bundles that are separated from each other and loosely arranged relative to each other within the cellulose blank structure 2.

The cellulose fibres CF may originate from a suitable cellulose raw material, such as a pulp material. Suitable pulp materials are for example fluff pulp, paper structures, or other cellulose fibre containing structures. The cellulose fibres CF may also be extracted from agricultural waste materials, for example wheat straws, fruit and vegetable peels, bagasse, or from other suitable sources. When for example using pulp as raw material for the cellulose blank structures 2, the pulp structure commonly needs to be separated in a separating unit, such as a suitable mill unit, before the airforming of the cellulose blank structures 2. In the separating unit, the pulp structure is separated into individual cellulose fibres, or into individual cellulose fibres and cellulose fibre bundles, and the better milling process the more individual cellulose fibres are formed. In other embodiments, only individual cellulose fibres may be used as raw material for the cellulose blank structures 2. With air-forming of the cellulose blank structures 2 is meant the formation of cellulose blank structures in a dry and controlled fibre forming process in which the cellulose fibres CF are air-formed to produce the cellulose blank structures 2. When forming the cellulose blank structures 2 in the air-forming process, the cellulose fibres CF are carried and formed to the cellulose blank structures 2 by air as carrying medium. It should be understood that even if the cellulose blank structures 2 are slightly compacted before the forming of the cellulose products 1 , such as compacting the cellulose blank structures 2 for feeding or transportation purposes, the cellulose blank structures 2 still comprise loose and separated cellulose fibres.

The air-forming process for forming the cellulose blank structures 2 is different from a normal papermaking process or a traditional wet-forming process, where water is used as carrying medium for the cellulose fibres when forming the paper or fibre structure. In the air-forming process, small amounts of water or other substances may if desired be added to the cellulose fibres in order to change the properties of the cellulose products, but air is still used as carrying medium in the forming process. The cellulose blank structures 2 may, if suitable have a dryness that is mainly corresponding to the ambient humidity in the atmosphere surrounding the air-formed cellulose blank structures 2. As an alternative, the dryness of the cellulose blank structures 2 can be controlled in order to have a suitable dryness level when forming the cellulose products 1 .

The air-formed cellulose blank structures 2 may be formed of cellulose fibres in a conventional air-forming process or in a cellulose blank air-forming module. The cellulose blank structures 2 may have a composition where the cellulose fibres CF are of the same origin or alternatively contain a mix of two or more types of cellulose fibres CF. The cellulose fibres CF used in the cellulose blank structures 2 are during the forming process of the cellulose products 1 bonded to each other with hydrogen bonds, due to applied forming pressure and forming temperature together with adequate moist content in the cellulose blank structures 2. The cellulose fibres CF may be mixed with other substances to a certain amount. With cellulose fibres is meant any type of cellulose fibres, such as natural cellulose fibres or manufactured cellulose fibres. The cellulose blank structures 2 may specifically comprise at least 95% dry weight cellulose fibres, or more specifically at least 99% dry weight cellulose fibres.

The air-formed cellulose blank structures 2 may have a single-layer or a multi-layer configuration. A cellulose blank structure 2 having a single-layer configuration is referring to a structure that is formed of one layer containing cellulose fibres CF. A cellulose blank structure 2 having a multi-layer configuration is referring to a structure that is formed of two or more layers comprising cellulose fibres, where the layers may have the same or different compositions or configurations.

The cellulose blank structures 2 may comprise one or more additional layers, where the one or more additional layers may be additional cellulose layers comprising cellulose fibres CF. The one or more additional layers may for example be arranged as carrying layers for one or more other layers of the cellulose blank structures 2. The one or more additional layers may act as reinforcement layers having a higher tensile strength than other layers of the cellulose blank structures 2. This is useful when one or more air-formed layers of the cellulose blank structures 2 have compositions with low tensile strength in order to avoid that the cellulose blank structures 2 will break during the forming of the cellulose products 1 . The one or more additional layers with higher tensile strength act in this way as a supporting structure for other layers of the cellulose blank structures 2. The one or more additional cellulose layers may be of a different composition than the rest of the cellulose blank structures 2, such as for example a tissue layer containing cellulose fibres, an airlaid structure comprising cellulose fibres, or other suitable layer structures. It is thus not necessary that the one or more additional cellulose layers are air-formed. Other suitable additional layers may also be used such as for example silicone coated structures, bio-based films, or other film structures.

The one or more air-formed layers of the cellulose blank structures 2 are fluffy and airy structures, where the cellulose fibres CF forming the structures are arranged relatively loosely relative to each other. The fluffy cellulose blank structures 2 are used for an efficient dry-forming of the cellulose products 1 , allowing the cellulose fibres CF to form the cellulose products 1 in an efficient way during the dry-forming process in the product forming unit II.

To form the cellulose products 1 from the air-formed cellulose blank structures 2 in the product forming unit II, the cellulose blank structures 2 are first provided from a suitable source. The cellulose blank structures 2 may be air-formed from cellulose fibres CF and arranged on rolls or in stacks. The rolls or stacks may thereafter be arranged in connection to the product forming unit II. As an alternative, the cellulose blank structures 2 may be air-formed from cellulose fibres CF in a non-illustrated cellulose blank air-forming module arranged in connection to the product forming unit U.

As shown in figure 3a, the cellulose blank structures 2 are arranged in connection to three-dimensional surfaces SSD of three-dimensional shaping structures S for forming a stack X of the plurality of three-dimensional shaping structures S with the cellulose blank structures 2 arranged in connection to the three-dimensional surfaces SSD. In the illustrated embodiment, a first cellulose blank structure 2i is arranged in connection to a three-dimensional surface SSD of a first three-dimensional shaping structure Si , a second cellulose blank structure 22 is arranged in connection to a three- dimensional surface SSD of a second three-dimensional shaping structure S2, and a third cellulose blank structure 2s is arranged in connection to a three-dimensional surface SSD of a third three-dimensional shaping structure S3. The stack X is formed of the first three-dimensional shaping structure Si with the first cellulose blank structure 2i, the second three-dimensional shaping structure S2 with the second cellulose blank structure 22, and the third three-dimensional shaping structure S3 with the third cellulose blank structure 2s, as shown in figure 3b, where the respective three-dimensional shaping structures with the cellulose blank structures have been stapled on top of each other in a stacking position PST.

The three-dimensional surface SSD of each three-dimensional shaping structure S is defined as a non-planar surface having a three-dimensional shape for an efficient forming operation in the forming mould M. The three-dimensional surface SSD of the three-dimensional shaping structure S has a surface configuration adapted to the configuration of the forming mould M for an efficient positioning of the stack X in the forming mould M. The three-dimensional surface SSD of the three-dimensional shaping structure S may have any suitable three-dimensional configuration, and the three- dimensional surface SSD may for example be arranged with elevated, undulating, rounded and/or step-like surface sections. Suitably, the three-dimensional surface SSD of the three-dimensional shaping structure S has a shape corresponding to or similar to a final shape of the cellulose product 1 formed in the forming mould M. In this embodiment, the three-dimensional shaping structures S suitably are arranged without suction openings.

Thereafter, the formed stack X is positioned in the forming mould M, and a plurality of cellulose products 1 are dry-formed into three-dimensional compressed structures CSD in a pressing operation OP, as shown in figure 3c. With the configuration of the stack X exemplified above, three cellulose products 1 can be formed simultaneously in the forming mould M during the pressing operation OP. The three-dimensional surfaces SSD of the three-dimensional shaping structures S have shapes corresponding to a shape of a three-dimensional pressing surface SPSD of the forming mould M. When positioning the stack X in the forming mould M, the cellulose products 1 can be dry-formed into the three-dimensional compressed structures CSD in the pressing operation OP by pressing and heating the stack X in the forming mould M with a forming pressure Pp and a forming temperature Tp.

As shown in for example figure 2a, the three-dimensional shaping structure S comprises an outer surface So and an inner surface Si. The inner surface Si is arranged opposite the outer surface So. The three-dimensional shaping structures S suitably have configurations that enables efficient forming of the stack X. The geometries of the outer surface So and the inner surface Si of the three-dimensional shaping structures S may be different in order to achieve a stack X where two or more three-dimensional shaping structures S can be positioned on top of each other without any gaps between two adjacent three- dimensional shaping structures S, or with only minor gaps between two adjacent three-dimensional shaping structures S. Such a configuration with cooperating surfaces is enabling an efficient forming of the cellulose products 1 from the cellulose blank structures 2 in the forming mould M, where the three-dimensional compressed structures CSD have uniform thickness. In other embodiments, the geometries of the outer surfaces So and the inner surfaces Si of the three-dimensional shaping structures S are designed for enabling a varied thickness of the three-dimensional compressed structures CSD, and in this way cellulose products 1 with areas having a higher thickness can be produced.

The cellulose products are dry-formed from the cellulose fibres CF in the cellulose blank structures 2, by pressing and heating the stack X of three-dimensional shaping structures S with the cellulose blank structures 2 in the forming mould M with a forming pressure PF and a forming temperature TF. The forming mould M may have the same function and configuration as described in the embodiment above in connection to figures 1 a-f, with similar functionality of the pressing operation OP.

As understood from figure 3c, the three-dimensional pressing surface SPSD of the first mould part 3a and the three-dimensional surface SSD of the uppermost three- dimensional shaping structure S in the stack X are configured as cooperating pressing surfaces during the pressing operation OP. The geometry of the three-dimensional pressing surface SPSD may be the same as or similar to the geometry of the inner surface of the three-dimensional shaping structures S. The inner surface of an upper three-dimensional shaping structure S is configured as a pressing surface that is cooperating with an outer surface of a direct adjacent lower three-dimensional shaping structure S.

When the stack X is positioned in the forming mould M, as illustrated in figure 3c, the three-dimensional pressing surface SPSD of the first mould part 3a and the outer surface of the third three-dimensional shaping structure S3 are configured as cooperating pressing surfaces during the pressing operation OP in the forming mould M. The inner surface of the third three-dimensional shaping structure S3 and the outer surface of the second three-dimensional shaping structure S2 are configured as cooperating pressing surfaces during the pressing operation OP in the forming mould M. The inner surface of the second three-dimensional shaping structure S2 and the outer surface of the first three-dimensional shaping structure Si are configured as cooperating pressing surfaces during the pressing operation OP in the forming mould M.

The three-dimensional pressing surface SPSD of the first mould part 3a is further configured as a pressing surface arranged to press the three-dimensional shaping structures S and the formed three-dimensional bodies B of cellulose fibres OF during the pressing operation OP, when the stack X is arranged between the first mould part 3a and the second mould part 3b. The stack X is in this way during the pressing operation OP in the forming mould M pressed between the first mould part 3a and the second mould part 3b, for forming a plurality of cellulose products 1 simultaneously from the cellulose blank structures 2.

The forming mould M is used for dry-forming the cellulose products 1 from the cellulose blank structures 2 in the pressing operation OP, and the three-dimensional shaping structures S are supporting the cellulose blank structures 2 during the pressing operation OP. The forming mould M is in the pressing operation OP dryforming the cellulose products 1 into three-dimensional compressed structures CSD by pressing and heating the cellulose fibres OF of the cellulose blank structures 2 in the forming mould M with a forming pressure Pp in the range of 1-600 MPa, preferably in the range of 1-100 MPa, more preferably in the range of 4-20 MPa, and a forming temperature Tp in the range of 60-300 °C, preferably in the range of 100-200 °C, more preferably in the range of 120-170 °C. In this way, the cellulose fibres CF in the cellulose blank structures 2 are integrated into the three-dimensional compressed structures CSD.

The forming pressure Pp may selectively be higher in specific parts or areas of the forming mould M. This higher forming pressure Pp may be used for forming sections of the cellulose products 1 having a higher stiffness.

The cellulose blank structures 2 may be compacted before dry-forming the cellulose products 1 in the forming mould M. The compacting operation is compressing the fibre structure of the cellulose blank structures 2 into a more dense structure, without influencing the general three-dimensional shape.

After the pressing operation OP in the forming mould M, the stack X comprising the formed three-dimensional compressed structures CSD and the three-dimensional shaping structures S are removed from the forming mould M, and the three- dimensional compressed structures CSD are separated from the three-dimensional shaping structures S. The shaping structures S may thereafter be reused.

Figure 4 schematically shows, side views and partly cross-section shown with diagonal lines, an embodiment example of a product forming unit II for dry-forming cellulose products, where the product forming unit II comprises a fibre transporting unit T and a forming mould M, and where a stack of three-dimensional shaping structures S and three-dimensional bodies of cellulose fibres is used during a pressing operation in the forming mould. In figure 4, the three-dimensional shaping structure comprises four shaping structures S1 , S2, S3 and S4. Figure 4 shows that the bottom shaping structure S1 , i.e. the first shaping structure S1 in the stack has a different shape than the remaining three shaping structures S2, S3, S4. It should be noted that in a different example, the first shaping structure S1 could have the same shape as the other remaining three shaping structures S2, S3, S4. Hence, all shaping structures 2 in the stack of shaping structures S could individually have. the same shape or as alternative the first/bottom shaping structure S1 , i.e. closest to the second mould part, could have a different shape than the remaining shaping structures S1-S3 in the stack. The shaping structures S1-S4 in figure 4 allows for simultaneous production of numerous cellulose products. As can be seen in figure 4, the first mould part 3a has three-dimensional pressing surface with a shape similar to the inner surface of each of the shaping structures and the second mould part 3b has a receiving surface similar in shape to the outer surface of each of the three-dimensional shaping structures S1- S4. The described shapes have the advantage that they allow forming of cellulose products with similar/identical three-dimensional shapes using only one forming mould and consequently only one pressing tool. The pressing tool can be any type of pressing tool that can apply adequate forming pressure to the forming mould and thus the cellulose products.

In the example shown in figure 4, the shaping structures S1-S4 have the same shape of the inner surface and the same shape of the outer surface in order to produce cellulose products with same three-dimensional shape. To avoid a problem with continuously expanding cellulose products, all shaping structures or at least the second from bottom shaping structure and above in the stack should have a design that allows for the same shape of the inner surface and the same shape of the outer surface between separate shaping structures. As can be seen from figure 4, all shaping structures S2-S3, not necessarily the first/bottom shaping structure S1 according to the above, should have side portions with a height in the pressing direction being of at least the same height as the height of the cellulose product in order to allow for a design with same/similar shape of inner surfaces and outer surfaces between the different shaping moulds.

According to one example not shown, several stacks of shaping structures as seen in figures 1-4 could be positioned next to each other in several forming moulds, i.e. one forming mould per stack, but still using only one pressing tool acting against all the forming mould simultaneously.

It will be appreciated that the above description is merely exemplary in nature and is not intended to limit the present disclosure, its application or uses. While specific examples have been described in the specification and illustrated in the drawings, it will be understood by those of ordinary skill in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the present disclosure as defined in the claims. Furthermore, modifications may be made to adapt a particular situation or material to the teachings of the present disclosure without departing from the essential scope thereof. Therefore, it is intended that the present disclosure not be limited to the particular examples illustrated by the drawings and described in the specification as the best mode presently contemplated for carrying out the teachings of the present disclosure, but that the scope of the present disclosure will include any embodiments falling within the foregoing description and the appended claims. Reference signs mentioned in the claims should not be seen as limiting the extent of the matter protected by the claims, and their sole function is to make claims easier to understand. REFERENCE SIGNS

1 : Cellulose product

2: Cellulose blank structure

3a: First mould part

3b: Second mould part

7: Suction opening

8: Flow channel

9: Receiving surface

11 : Support structure

A: Air

B: Three-dimensional body

CF: Cellulose fibres

CSD: Three-dimensional compressed structure

H: Hood

M: Forming mould

OP: Pressing operation

PF: Forming pressure

PN: Negative pressure

PST: Stacking position

S: Three-dimensional shaping structure

SSD: Three-dimensional surface

Si: Inner surface

So: Outer surface

SPSD: Three-dimensional pressing surface

T: Fibre transporting unit

Tp: Forming temperature

Tpo: Fibre outlet

II: Product forming unit

X: Stack

Claims

1 . A method for dry-forming three-dimensional cellulose products (1) from cellulose fibres (CF) in a product forming unit (II) comprising a forming mould (M), wherein the method comprises the steps: providing loose and separated cellulose fibres (CF) and feeding the loose and separated cellulose fibres (CF) to a plurality of three-dimensional shaping structures (S) each comprising a three-dimensional surface (SSD); arranging the loose and separated cellulose fibres (CF) in connection to the three-dimensional surfaces (SSD) of the three-dimensional shaping structures

(S), wherein the three-dimensional surfaces (SSD) have shapes corresponding to a shape of a three-dimensional pressing surface (SPSD) of the forming mould (M); forming a stack (X) of the plurality of three-dimensional shaping structures (S) with the cellulose fibres (CF) arranged in connection to the three- dimensional surfaces (SSD); positioning the stack (X) in the forming mould (M), and dry-forming a plurality of cellulose products (1) into three-dimensional compressed structures (CSD) in a pressing operation (OP) from the cellulose fibres (CF), by pressing and heating the stack (X) of three-dimensional shaping structures (S) with the cellulose fibres (CF) in the forming mould (M) with a forming pressure (Pp) and a forming temperature (Tp).

2. The method according to claim 1 , wherein the product forming unit (II) comprises a fibre transporting unit

(T), wherein the method further comprises the steps: providing loose and separated cellulose fibres (CF) to the fibre transporting unit (T), and feeding the loose and separated cellulose fibres (CF) in the fibre transporting unit (T) by means of a flow of air (A) as carrying medium for the cellulose fibres (CF) to the plurality of three-dimensional shaping structures (S); arranging the loose and separated cellulose fibres (CF) onto the three- dimensional surfaces (SSD) of the three-dimensional shaping structures (S) by means of the flow of air (A) for air-forming three-dimensional bodies (B) of cellulose fibres (CF), and forming the stack (X) of the plurality of three- dimensional shaping structures (S) with the cellulose fibres (CF) arranged onto to the three-dimensional surfaces (SSD).

3. The method according to claim 2, wherein the plurality of three-dimensional shaping structures (S) each comprises an outer surface (So) and an inner surface (Si), wherein the three- dimensional surfaces (SSD) are arranged as the outer surfaces (So) and/or the inner surfaces (Si), wherein the three-dimensional shaping structures (S) comprise a plurality of suction openings (7) connecting the outer surfaces (So) and the inner surfaces (Si), wherein the method further comprises the steps: arranging the loose and separated cellulose fibres (CF) onto the three- dimensional surfaces (SSD) by means of the flow of air (A) for air-forming the three-dimensional bodies (B) of cellulose fibres (CF), and applying a negative pressure (PN) via the suction openings (7) for distributing the cellulose fibres (CF) onto the three-dimensional surfaces (SSD).

4. The method according to claim 1 , wherein the method further comprises the steps: providing loose and separated cellulose fibres (CF) and air-forming the loose and separated cellulose fibres (CF) into cellulose blank structures (2); arranging the cellulose blank structures (2) in connection to the three-dimensional surfaces (SSD) of the three- dimensional shaping structures (S), and forming the stack (X) of the plurality of three-dimensional shaping structures (S) with the cellulose blank structures (2) arranged in connection to the three-dimensional surfaces (SSD).

5. The method according to any preceding claim, wherein the forming pressure (PF) is in the range of 1-600 MPa, preferably in the range of 1-100 MPa, more preferably in the range of 4-20 MPa, and the forming temperature (TF) is in the range of 60-300 °C, preferably in the range of 100-200 °C, more preferably in the range of 120-170 °C.

6. The method according to any preceding claim, wherein the method further comprises the step: dry-forming the cellulose product (1) in the forming mould (M) from the cellulose fibres (CF) in the pressing operation (OP), wherein during dry-forming the three-dimensional shaping structures (S) are supporting the cellulose fibres (CF), and wherein the cellulose fibres (CF) are integrated into the three-dimensional compressed structures (CSD).

7. The method according to any preceding claim, wherein the method further comprises the steps: removing the stack (X) from the forming mould (M) after the pressing operation (OP); and separating the three-dimensional compressed structures (CSD) from the three-dimensional shaping structures (S).

8. The method according to any preceding claim, wherein the three-dimensional shaping structures (S) are arranged as three-dimensional net structures or as three-dimensional perforated structures.

9. The method according to any preceding claim, wherein the forming mould (M) comprises a first mould part (3a) and a corresponding second mould part (3b), wherein the first mould part (3a) and/or the second mould part (3b) comprises the three-dimensional pressing surface (SPSD), wherein the method further comprises the steps: arranging the stack (X) into a position between the first mould part (3a) and corresponding second mould part (3b); applying the forming pressure (Pp) by pressing the stack (X) between the first mould part (3a) and corresponding second mould part (3b); and applying the forming temperature (Tp) onto the cellulose fibres (CF) in the forming mould (M).

10. A product forming unit (II) for dry-forming three-dimensional cellulose products (1) from loose and separated cellulose fibres (CF), wherein the product forming unit (II) comprises a forming mould (M), wherein the product forming unit (II) is configured for arranging the loose and separated cellulose fibres (CF) onto three-dimensional surfaces (SSD) of a plurality of three-dimensional shaping structures (S), wherein the three- dimensional surfaces (SSD) have shapes corresponding to a shape of a three- dimensional pressing surface (SPSD) of the forming mould (M); wherein the forming mould (M) is configured for dry-forming a plurality of cellulose products (1) into three-dimensional compressed structures (CSD) in a pressing operation (OP) from the cellulose fibres (CF), wherein a formed stack (X) of the plurality of three-dimensional shaping structures (S) with the cellulose fibres (CF) arranged onto the three-dimensional surfaces (SSD) is positioned in the forming mould (M), wherein the stack (X) of the three-dimensional shaping structures (S) with the cellulose fibres (CF) is pressed and heated in the forming mould (M) with a forming pressure (Pp) and a forming temperature (Tp).

11 . A product forming unit (II) according to claim 10, wherein the product forming unit (II) further comprises a fibre transporting unit (T), wherein the fibre transporting unit (T) is configured for feeding loose and separated cellulose fibres (CF) from the fibre transporting unit (T) to the three- dimensional shaping structures (S) by means of a flow of air (A) as carrying medium for the cellulose fibres (CF), wherein the loose and separated cellulose fibres (CF) are arranged onto three-dimensional surfaces (SSD) of the three- dimensional shaping structures (S) by means of the flow of air (A) for air-forming three-dimensional bodies (B) of cellulose fibres (CF), wherein the stack (X) is formed of the plurality of three-dimensional shaping structures (S) with the cellulose fibres (CF) arranged onto to the three-dimensional surfaces (SSD).

12. The product forming unit (II) according to claim 11 , wherein the three-dimensional shaping structures (S) each comprises an outer surface (So) and an inner surface (Si), wherein the three-dimensional surfaces (SSD) are arranged as the outer surfaces (So) and/or the inner surfaces (Si), wherein the three-dimensional shaping structures (S) comprise a plurality of suction openings (7) connecting the outer surfaces (So) and the inner surfaces (Si).

13. The product forming unit (II) according to claim 10, wherein the stack (X) is formed of the plurality of three-dimensional shaping structures (S) with cellulose blank structures (2) arranged in connection to the three-dimensional surfaces (SSD), wherein the loose and separated cellulose fibres (CF) are air-formed into the cellulose blank structures (2).

14. The product forming unit (II) according to any of claims 10 to 13, wherein the forming pressure (PF) is in the range of 1-600 MPa, preferably in the range of 1-100 MPa, more preferably in the range of 4-20 MPa, and the forming temperature (TF) is in the range of 60-300 °C, preferably in the range of 100-200 °C, more preferably in the range of 120-170 °C.

15. The product forming unit (II) according to any of claims 10 to 14, wherein the forming mould (M) is configured for dry-forming the cellulose products (1) from the cellulose fibres (CF) in the pressing operation (OP), wherein the three-dimensional shaping structures (S) are configured for supporting the cellulose fibres (CF), and wherein the cellulose fibres (CF) are integrated into the three-dimensional compressed structures (CSD).

16. The product forming unit (II) according to any of claims 10 to 15, wherein the three-dimensional shaping structures (S) are arranged as three-dimensional net structures or as three-dimensional perforated structures.

17. The product forming unit (II) according to any of claims 10 to 16, wherein the forming mould (M) comprises a first mould part (3a) and a corresponding second mould part (3b), wherein the first mould part (3a) and/or the second mould part (3b) comprises the three-dimensional pressing surface (SPSD), wherein the forming mould (M) is configured for applying the forming pressure (PF) by pressing the stack (X) between the first mould part (3a) and corresponding second mould part (3b), and wherein the forming mould (M) is configured for applying the forming temperature (TF) onto the cellulose fibres (CF).