SE1950299A1

SE1950299A1 - A method for producing cellulose products and a forming unit

Info

Publication number: SE1950299A1
Application number: SE1950299A
Authority: SE
Inventors: Björn Arlerot; Olle Högblom
Original assignee: Pulpac AB
Priority date: 2019-03-08
Filing date: 2019-03-08
Publication date: 2020-09-09
Also published as: SE543410C2

Abstract

A method for producing cellulose products (2) from a cellulose blank (3), wherein the method comprises the steps; dry-forming the cellulose blank (3) in a forming unit (13), wherein the forming unit (13) comprises a mill unit (14), a forming chamber (15), and a forming wire (16) arranged in connection to the forming chamber (15), wherein the mill unit (14) is arranged for separating fibres from a pulp structure (20) and distributing the separated fibres into the forming chamber (15), wherein the forming chamber (15) comprises a forming belt unit (17) arranged in connection to the forming wire (16), wherein the forming wire (16) and the forming belt unit (17) are arranged at an output section (18) of the forming chamber (15), wherein the forming wire (16) and the forming belt unit (17) are transporting the separated fibres towards the output section (18); arranging the cellulose blank (3) in a forming mould (4) between a first mould part (5a) and a second mould part (5b); heating the cellulose blank (3) to a forming temperature in the range of 100°C to 300°C; and forming the cellulose products (2) from the cellulose blank (3) in the forming mould (4), by pressing the heated cellulose blank (3) with an isostatic forming pressure (Piso) in the range 1-100 MPa, preferably 4-20 MPa.

Description

A METHOD FOR PRODUCING CELLULOSE PRODUCTS AND A FORMINGUNIT TECHNICAL FIELD The present disclosure relates to a method for producing cellulose productsfrom a cellulose blank, where the cellulose blank is formed in a forming unit.The formed cellulose blank is arranged in a forming mould between a firstmould part and a second mould part. The cellulose blank is heated to a formingtemperature and the cellulose products are formed from the cellulose blank inthe forming mould by pressing the heated cellulose blank with an isostaticforming pressure. The disclosure further relates to a forming unit for forming a cellulose blank according to the method for producing cellulose products.

BACKGROUND Cellulose fibres are often used as raw material for producing or manufacturingproducts. Products formed of cellulose fibres can be used in many differentsituations where there is a need for having sustainable products. A wide rangeof products can be produced from cellulose fibres and a few examples aredisposable plates and cups, blank structures and packaging materials.Packages produced from cellulose fibres may for example be used forpackaging of liquids, dry materials and other types of goods.

Forming moulds are commonly used when manufacturing cellulose productsfrom raw materials including cellulose fibres, and traditionally the celluloseproducts have been produced with wet-forming techniques. A materialcommonly used for cellulose fibre products is wet moulded pulp. Wet mouldedpulp has the advantage of being considered as a sustainable packagingmaterial, since it is produced from biomaterials and can be recycled after use.Consequently, wet moulded pulp has been quickly increasing in popularity for different applications. Wet moulded pulp articles are generally formed byimmersing a suction forming mould into a liquid or semi liquid pulp suspensionor slurry comprising cellulose fibres, and when suction is applied, a body ofpulp is formed with the shape of the desired product by fibre deposition ontothe forming mould. With all wet-forming techniques there is a need for dryingof the wet moulded product, where the drying is a very time and energyconsuming part of the production. The demands on aesthetical, chemical andmechanical properties of cellulose products are increasing, and due to theproperties of wet-formed cellulose products, the mechanical strength,flexibility, and chemical properties are limited. lt is also difficult in wet-formingprocesses to control the mechanical properties of the products with high precision.

One development in the field of producing cellulose products is the forming ofcellulose fibres without using wet-forming techniques. lnstead of forming thecellulose products from a liquid or semi liquid pulp suspension or slurry, an air-formed cellulose blank is used. The air-formed cellulose blank is inserted intoa forming mould comprising a deformation element and during the forming ofthe cellulose products the cellulose blank is subjected to a high formingpressure and a high forming temperature. ln traditional air-forming processes, such as air-laying or air-carding, an air-forming tower is used for distributing the fibres on a forming wire. The air-forming tower often comprises fibre separating rollers or other fibre separationmeans arranged in one or more rows between a fibre inlet and a forming towerhousing bottom to distribute the cellulose fibres evenly onto the forming wire.The formation of the cellulose blank in the traditional air-forming process is atime consuming operation. By omitting the separating rollers or other fibreseparation means and forming the fibres directly onto the forming wire theprocess speed can be improved. However, when omitting the separatingrollers or other fibre separation means, the fibres are unevenly distributed on the forming wire, which is leading to cellulose blank structures with poorquality.

There is thus a need for an improved method for forming cellulose productsfrom a dry-formed cellulose blank, where a forming unit is used for dry-forming the cellulose blank.

SUMMARY An object of the present disclosure is to provide a method for producingcellulose products from a cellulose blank, and a forming unit for dry-forming acellulose blank to be used in the method, where the previously mentionedproblems are avoided. This object is at least partly achieved by the features ofthe independent claims. The dependent claims contain further developmentsof the method and the forming unit.

The disclosure concerns a method for producing cellulose products from acellulose blank. The cellulose blank is dry-formed in a forming unit, whereinthe forming unit comprises a mill unit, a forming chamber, and a forming wirearranged in connection to the forming chamber. The mill unit is arranged forseparating fibres from a pulp structure and distributing the separated fibres intothe forming chamber. The forming chamber comprises a forming belt unitarranged in connection to the forming wire, and the forming wire and theforming belt unit are arranged at an output section of the forming chamber,where the forming wire and the forming belt unit are transporting the separatedfibres towards the output section. The cellulose blank is arranged in a formingmould between a first mould part and a second mould part. The cellulose blankis heated to a forming temperature in the range of 100°C to 300°C. Thecellulose products are formed from the cellulose blank in the forming mould,by pressing the heated cellulose blank with an isostatic forming pressure in therange 1-100 MPa, preferably 4-20 MPa.

Advantages with these features are that the formation of the cellulose blankcan be made in a fast and efficient operation with an increased process speed.With the forming belt unit arranged in the forming chamber, the fibres aredistributed evenly on the forming wire, which is leading to a cellulose blankstructure having high quality suitable for isostatic pressure forming. Further,with this configuration of the forming unit, the forming unit can be made more cost efficient with a more compact layout.

According to an aspect of the disclosure, an inner belt side of the forming beltunit is arranged at an angle in relation to an inner belt side of the forming wire.A gap section is formed between the inner belt side of the forming belt unit andthe inner belt side of the forming wire. The gap section has a narrowingconfiguration towards the output section, wherein the cellulose blank is formedfrom the separated fibres in the gap section. The gap section is efficientlyforming the cellulose blank with an even structure through the interactionbetween the forming wire and the forming belt unit.

According to another aspect of the disclosure, the angle is in the range 10°-80°, preferably 20°-70°, and more preferably 30°-60°. These ranges areproviding an efficient forming of the cellulose blank.

According to an aspect of the disclosure, a first vacuum box is arranged inconnection to the inner belt side of the forming wire for controlling the flow ofair in the forming chamber, and for distributing the separated fibres onto theinner belt side of the forming wire. The first vacuum box is used for securing an efficient flow in the forming chamber towards the forming wire.

According to another aspect of the disclosure, a second vacuum box isarranged in connection to the inner belt side of the forming belt unit forcontrolling the flow of air in the forming chamber, and for distributing theseparated fibres onto the inner belt side of the forming belt unit. The secondvacuum box is used for securing an efficient flow in the forming chamber towards the forming belt unit.

According to an aspect of the disclosure, the method further comprises thesteps: driving the forming wire with a forming wire speed, and driving theforming belt unit with a forming belt speed. The forming wire is transportingseparated fibres in the forming chamber towards the output section, and theforming belt unit is transporting separated fibres in the forming chambertowards the output section. The forming wire and the forming belt unit are inthis way cooperating to distribute the separate fibres in the forming chamberand to distribute the formed cellulose blank through the output section of the forming chamber.

According to other aspects of the disclosure, the forming belt speed is equalto or greater than the forming wire speed, or the forming belt speed is greaterthan the forming wire speed. With these speed relationships, an efficientforming of the cellulose blank is achieved, where the cellulose blank can beproduced with high quality.

According to a further aspect of the disclosure, during forming of the celluloseblank, the separated fibres are carried by air as carrying medium in the formingchamber. Air is used in the cellulose blank forming process for distributing theseparated cellulose fibres onto the forming wire and the forming belt unit. Thecellulose blank is in this way dry-formed in the forming chamber.

According to an aspect of the disclosure, the forming mould comprises aforming cavity and a deformation element. The first mould part and the secondmould part are moved in relation to each other in a pressing direction, and thefirst mould part is pressed in relation to the second mould part towards eachother during forming of the cellulose products. The forming cavity is formedand enclosed by the first mould part and the second mould part during formingof the cellulose products. The isostatic forming pressure is exerted on thecellulose blank by the deformation element during forming of the celluloseproducts, wherein the deformation element during forming of the celluloseproducts is arranged in the forming cavity. With this configuration ofthe forming mould process, an efficient forming of the cellulose products is accomplished.

According to another aspect of the disclosure, during forming of the celluloseproducts the deformation element through deformation is arranged to establisha uniform pressure in all directions in the forming mould on the cellulose blank,wherein the deformation element during forming of the cellulose products isexerting an isostatic forming pressure on the cellulose blank in the range 1-100 MPa, preferably 4-20 MPa. Using isostatic pressure within these pressureranges, cellulose products with high quality can be produced.

According to a further aspect of the disclosure, the cellulose blank iscompacted before arranging the cellulose blank in the forming mould betweenthe first mould part and the second mould part. The compacting of the celluloseblank is facilitating the further handling of the cellulose blank, e.g. when beingrolled up or transported to the forming mould.

According to an aspect of the disclosure, the cellulose blank is compacted inthe forming unit in connection to the output section. The forming belt unitcomprises a first compression roller arranged at the output section, and theforming wire comprises a second compression roller arranged at the outputsection. The first compression roller and the second compression roller arearranged to cooperate with each other for compacting the formed celluloseblank. The use of compression rollers is providing an efficient compacting ofthe cellulose blank with a simple construction.

According to another aspect of the disclosure, the cellulose blank is dry-formedto a fibre structure having a dry basis weight in the range of 600-3000 g/m2.Within this dry basis weight range, the formed fibre structure constituting thecellulose blank will have properties suitable for forming in the forming mould providing desired properties of the formed cellulose products.

The disclosure further concerns a forming unit for dry-forming a cellulose blankaccording to the method for producing cellulose products. The forming unitcomprises a mill unit, a forming chamber, and a forming wire arranged in connection to the forming chamber. The mill unit is arranged for separating fibres from a pulp structure and distributing the separated fibres into theforming chamber. The forming chamber comprises a forming belt unit arrangedin connection to the forming wire, and the forming wire and the forming beltunit are arranged at an output section of the forming chamber. The formingwire and the forming belt unit are transporting the separated fibres towards theoutput section. An inner belt side of the forming belt unit is arranged at an anglein relation to an inner belt side of the forming wire. A gap section is formedbetween the inner belt side of the forming belt unit and the inner belt side ofthe forming wire, wherein the gap section has a narrowing configurationtowards the output section. Advantages with these features are that theformation of the cellulose blank can be made in the forming unit with highspeed. With the forming belt unit arranged in the forming chamber, the fibresare distributed evenly on the forming wire, which is leading to a cellulose blank structure having high quality, suitable for isostatic pressure forming.

According to an aspect of the disclosure, the angle is in the range 10°-80°,preferably 20°-70°, and more preferably 30°-60°. These ranges are providingan efficient forming of the cellulose blank.

According to another aspect of the disclosure, the forming unit furthercomprises a cellulose fibre recycling unit arranged for transporting residualcellulose blank fibre material from a forming mould to the mill unit. With thefibre recycling unit, residual cellulose fibres can be recycled and used again for forming the cellulose blank.

BRIEF DESCRIPTION OF DRAWINGS The disclosure will be described in greater detail in the following, with reference to the attached drawings, in which Fig. 1 shows schematically, a forming mould system in a perspective view according to the disclosure, Fig. za-d Fig. 3a-b Fig. 4 Fig 5a-b.

Fig. 6 Fig. 7 Fig. 8a-c Fig. 9a-b show schematically, cross-sectional side views of a forming mouldaccording to the disclosure, show schematically, a view from above and a cross-sectional view from above of the forming mould according to the disclosure, shows schematically, a deformation element exerting an isostaticforming pressure according to the disclosure, show schematically, side views of production lines for celluloseproducts with a forming unit according to the disclosure, shows schematically, in a perspective view, a forming unit according to the disclosure. shows schematically, a side view of a forming unit according tothe disclosure, show schematically, side views of sections of forming unit embodiments according to the disclosure, and show schematically, a side view of an alternative configuration ofthe forming unit according to the disclosure.

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.

The disclosure concerns a method for producing cellulose products from a cellulose blank, where the cellulose blank is formed in a forming unit. ln the forming unit, the cellulose blank is air-formed onto a forming wire. A forming mould is used for forming the cellulose products from the air-formed celluloseblank.

With a cellulose blank is meant a fibre web structure produced from cellulosefibres. With air-forming of the cellulose blank is meant the formation of acellulose blank in a dry-forming process in which cellulose fibres are air-formedto produce the cellulose blank. When forming the cellulose blank in the air-forming process, the cellulose fibres are carried and formed to the fibre blankstructure by air as carrying medium. This is different from a normalpapermaking process or a traditional wet-forming process, where water is usedas carrying medium for the cellulose fibres when forming the paper or fibrestructure. ln the air-forming process, small amounts of water or othersubstances may if desired be added to the cellulose fibres in order to changethe properties of the cellulose product, but air is still used as carrying mediumin the forming process. The cellulose blank may have a dryness that is mainlycorresponding to the ambient humidity in the atmosphere surrounding the dry- formed cellulose blank. ln figure 1, a forming mould system 1 is shown. The forming mould system 1comprises the forming mould 4, where the forming mould 4 is having a firstmould part 5a, a second mould part 5b, a forming cavity 6, and a deformationelement 7. The deformation element 7 is during forming of the celluloseproducts 2 arranged to exert a forming pressure PF on the cellulose blank 3.During the forming, the deformation element 7 is deformed to exert a pressureon the cellulose blank 3 and through the deformation an even pressuredistribution is achieved in the forming mould 4, even if the cellulose products2 are having complex three-dimensional shapes or if the cellulose blank 3 is having a varied thickness.

The cellulose blank 3 may have a composition where the fibres are ofthe sameorigin or alternatively contain a mix of two or more types of cellulose fibres,depending on the desired properties of the cellulose products 2. The cellulose fibres used in the cellulose blank 3 are during the forming of the cellulose products 2 strongly bonded to each other with hydrogen bonds. The cellulosefibres may be mixed with other substances or compounds to a certain amountas will be further described below. With cellulose fibres is meant any type ofcellulose fibres, such as natural cellulose fibres or manufactured cellulose fibres.

The cellulose blank 3 may comprise one or more additives that are altering themechanical, hydrophobic, and/or oleophobic properties of the celluloseproducts 2. Tests have shown that if the cellulose blank 3 contains at least70% of cellulose fibres, desired mechanical properties of the cellulose product2 can be achieved. ln order to achieve the desired properties of the formedcellulose products 2, the cellulose fibres should be strongly bonded to eachother through fibril aggregation in a way so that the resulting cellulose products2 will have good mechanical properties. The additives used may therefore notimpact the bonding of the cellulose fibres during the forming process to a high extent.

As a non-limiting example, the cellulose blank 3 may have a materialcomposition of 70-99.9% dry wt cellulose fibres and 0.1 -30% dry wt of the oneor more additives. ln another embodiment, the cellulose blank 3 may have amaterial composition of 80-99.9% dry wt cellulose fibres and 0.1-20% dry wtof the one or more additives. ln a further embodiment, the cellulose blank 3may have a material composition of 90-99.9% dry wt cellulose fibres and 0.1-10% dry vvt of the one or more additives. Depending on the amount of cellulosefibres and additives used in the cellulose blank 3, the cellulose products 2 can have different properties.

The one or more additives of the cellulose blank 3 may be, as a non-limitingexample, starch compounds, rosin compounds, butanetetracarboxylic acid,gelatin compounds, alkyl ketene dimer (AKD), Alkenyl Succinic Anhydride(ASA), and/or flourocarbons. These additives are commonly used in theforming of cellulose products and are therefore not described in detail. Starchcompounds, gelatin acid, and compounds, butanetetracarboxylic 11 fluorocarbons may for example be used for altering the mechanical properties,such as strength or stiffness, of the cellulose product. Rosin compounds, a|ky|ketene dimer (AKD), Alkenyl Succinic Anhydride (ASA), and fluorocarbonsmay for example be used for altering the hydrophobic properties of thecellulose products. Fluorocarbons may for example be used also for alteringthe oleophobic properties of the cellulose product. The one or more additivesof the cellulose blank 3 may be added to the cellulose blank 3 before formingthe cellulose products, for example when dry-forming the cellulose blank 3.

The cellulose blank 3 may have a single-layer or a multi-layer structure. Acellulose blank 3 having a single-layer structure is referring to a cellulose blankstructure that is formed of one layer containing cellulose fibres. A celluloseblank 3 having a multi-layer structure is referring to a cellulose blank structurethat is formed of two or more layers containing cellulose fibres, where the layers may have the same or different compositions or configurations. ln order to form the cellulose products 2, the cellulose blank 3 is arranged inthe forming mould 4, where the cellulose blank 3 is heated to a specific formingtemperature TF and pressed with a specific forming pressure PF in the formingcavity 6 of the forming mould 4. When forming the cellulose products 2, a forceF is applied to the first forming mould part 5a and/or the second forming mouldpart 5b, as illustrated in the figures. The applied force F is during the formingprocess establishing the forming pressure PF in the forming cavity 6 exertedon the cellulose blank 3. According to the disclosure, when forming thecellulose blank 3 in the forming mould 4, a forming pressure PF in the range 1-100 MPa and a forming temperature TF in the range of 100°C to 300°C areapplied to the cellulose blank 3. The cellulose fibres in the cellulose blank 3will in the forming process be bonded to each other in a way so that theresulting cellulose products 2 will have good mechanical properties. Testshave shown that higher forming temperatures will give stronger bondingbetween the cellulose fibres when being pressed at a specific forming pressure. 12 With forming temperatures above 100°C together with a forming pressure ofat least 1 MPa, the cellulose fibres will be strongly bonded to each other withhydrogen bonds. A higher forming temperature will increase the fibrilaggregation, water resistance, Young's modulus and the mechanicalproperties of the final cellulose product. The high pressure is important for fibrilaggregation between the cellulose fibres in the cellulose products 2. Attemperatures higher than 300°C, the cellulose fibres will be thermallydegraded and therefore temperatures above 300°C should be avoided. Theforming pressure and the forming temperature may be chosen to be suitable for the specific cellulose products 2 to be produced.

Tests have shown that when forming the cellulose products 2 from celluloseblanks 3, suitable forming pressure levels are, as described above, in therange of 1-100 MPa, and suitable forming temperature levels are in the rangeof 100°C to 300°C. However, forming pressure levels in the range of 4-20 MPa,and temperature levels in the range of 140°C to 200°C are often sufficient in order to achieve cellulose products 2 with desired properties.

The cellulose products 2 may be formed in the forming mould 4 during aforming time period in a range of 0.001 to 20 seconds. As an alternative, theforming time period may be in a range of 0.01 to 15.0 seconds or in a range of0.1 to 10.0 seconds. The time period is chosen so that the desired propertiesof the cellulose products 2 are achieved. Longer forming time periods can beneeded if the multi-layer cellulose blank 3 is heated in the forming mould 4,compared to a pre-heated cellulose blank 3.

By holding a specific forming pressure at a specific forming temperature for acertain period of time, the fibril aggregation in the cellulose fibres of thecellulose blank 3 will form the cellulose products 2, with a cellulose fibrestructure having mechanical properties similar to thermoplastic materials. lf asa non-limiting example, the forming pressure is 4 MPa, the formingtemperature is 150°C, and the forming time period is 5 seconds, cellulose products 2 with a fibre structure with mechanical properties close to 13 thermoplastic materials can be achieved. The forming time period may asdescribed above for example range from 0.001 seconds to several seconds,depending on the forming temperature of the cellulose blank 3 and the formingpressure applied to the cellulose blank 3 in the forming mould 4.

The dry-forming of the cellulose blank 3 may take place as a separate processstep, in which the cellulose blank 3 may be stacked in sheets or arranged asa rolled web, before forming of the cellulose products 2. As an alternative, thedry-forming of the cellulose blank 3 may be part of a continuous process, inwhich the cellulose products 2 are formed in the forming mould 4. The dry-forming of the cellulose blank 3 will then be an initial process step beforearranging, heating, and pressing the cellulose blank 3 in the forming mould 4.

The heating of the cellulose blank 3 may take place before the pressing in theforming mould 4 or at least partly before the pressing in the forming mould 4.As an alternative, the heating of the cellulose blank 3 may take place in theforming mould 4 when being pressed. The heating of the cellulose blank 3 mayfor example be accomplished through heating the forming mould 4 beforepressing the cellulose blank 3. The pressure may also be applied beforeheating the cellulose blank 3, and for example the heating of the celluloseblank 3 may take place in the forming mould 4 during pressing.

The cellulose blank 3 may be arranged into the forming mould 4 in any suitableway, and as an example, the cellulose blank 3 may be manually arranged inthe forming mould 4. Another alternative is to arrange a feeding device for thecellulose blank 3, which is transporting the cellulose blank 3 to the formingmould 4. The feeding device could for example be a conveyor belt, an industrialrobot, or any other suitable manufacturing equipment. lf the dry-forming of thecellulose blank 3 is part of a continuous manufacturing process in which thecellulose products are produced, the cellulose blank 3 may be fed to theforming mould 4 from a dry-forming unit. More specifically, the cellulose blank3 could be intermittently fed to the forming mould 4 by a feeding unit if desired. 14 The first mould part 5a and the second mould part 5b are movably arranged inrelation to each other in a pressing direction Dp and further arranged to bepressed in relation towards each other during forming of the cellulose products2 with the force F. The force F may vary during the forming process anddepend on the type of cellulose products 2 formed and the forming equipmentused. When forming the cellulose products 2, the cellulose blank 3 is arrangedin the forming mould 4 when the forming mould is in an open state betweenthe first mould part 5a and the second mould part 5b. The forming cavity 6 maybe arranged with a shape that is corresponding to the final shape of thecellulose products 2 that are formed in the forming mould 4. The celluloseblank 3 is arranged in a way in the forming mould 4 so that during the formingprocess the forming cavity 6 is fully or partly covered by the cellulose blank 3.When the cellulose blank 3 has been arranged in the forming mould 4, the firstmould part 5a and the second mould part 5b are moved in relation to eachother during the forming process.

The forming mould system 1 can for example be constructed so that the firstmould part 5a or the second mould part 5b is movable and arranged to movetowards the other mould part during the forming process, where the othermould part is stationary or non-movably arranged. ln an alternative solution,both the first mould part 5a and the second mould part 5b are movablyarranged, where the first mould part 5a and the second mould part 5b aredisplaced in directions towards each other during the forming process. Themoving mould part or alternatively moving mould parts may be displaced witha suitable actuator, such as a hydraulic, pneumatic, or electric actuator. Acombination of different actuators may also be used. The relative speedbetween the first mould part 5a and the second mould part 5b during theforming process is chosen so that the cellulose blank 3 is evenly distributed inthe forming cavity 6 during the forming process. The actuator or actuators usedfor moving the first mould part 5a, or alternatively the second mould part 5b,or both mould parts may for example be pressure controlled, wherein therelative movement of the first mould part 5a in relation to the second mould part 5b is stopped when the correct forming pressure is established in the forming mould. ln figures 2a-d and figures 4a-b, an embodiment of the forming mould 4 of theforming mould system 1 is shown. ln figures 2a-d, the forming mould 4 isshown in cross-sectional side views of different forming steps of the formingprocess. ln figure 3a, the forming mould 4 of the embodiment is shown in aview from above, and in figure 3b, the forming mould 4 of the embodiment isshown in a cross-sectional view from above along a p|ane P indicated in figure2d. ln the embodiment, as i||ustrated in figures 2a-d and figures 3a-b, the formingmould system 1 for forming three-dimensional cellulose products 2 from an air-formed cellulose blank 3 comprises a forming mould 4 having a first mould part5a, a second mould part 5b, a forming cavity 6, and a deformation element 7.The forming cavity 6 is formed and enclosed by the first mould part 5a and thesecond mould part 5b during the forming of the cellulose products 2, as shownin figure 2d. During forming of the cellulose products 2, the deformationelement 7 is arranged in the forming cavity 6 and exerting a forming pressure PF on the cellulose blank 3. ln the embodiment, as shown in figure 2a, the first mould part 5a comprises afirst side wall 8a, an upper surface 8b, and a lower surface 8c. The first sidewall 8a is surrounding the first mould part 5a. The deformation element 7 isattached to the lower surface 8c of the first mould part 5a with suitableattachment means, such as for example glue or mechanical fastening members.

As shown in figure 2a, the second mould part 5b comprises a second side wall9 with an outer wall section 9a, an inner wall section 9b, and an upper wallsection 9c. The second mould part 5b has further a bottom wall 10 with anouter wall section 10a and an inner wall section 10b. ln this embodiment, theforming cavity 6 is arranged in the second mould part 5b and delimited by the 16 inner wall section 9b of the second side wall 9 and the inner wall section 10bof the bottom wall 10.

The first mould part 5a and the second mould part 5b are movable in relationto each other in a pressing direction Dp and arranged to be pressed in relationtowards each other during forming of the cellulose products 2. ln theembodiment, the first mould part 5a is movably arranged in the pressingdirection Dp and the second mould part 5b is stationary. The first mould part5a and the second mould part 5b may be arranged in a suitable stand or framestructure to hold the mould parts, as shown schematically in figure 1, and anactuator arrangement may be used for moving the first mould part 5a. Whenforming the cellulose products 2, the cellulose blank 3 is arranged between thefirst mould part 5a and the second mould part 5b when the forming mould is inan open state, as shown in figure 2a. The cellulose blank 3 is in thisembodiment arranged in a way between the first mould part 5a and the secondmould part 5b so that the forming cavity 6 is covered by the cellulose blank 3.When the cellulose blank 3 is arranged in the forming mould 4 as describedabove, the first mould part 5a and the second mould part 5b are ready to bemoved in relation to each other during the forming process. ln the forming stepwhen the first mould part 5a is moving in the pressing direction Dp towards thesecond mould part 5b, the deformation element 7 is pushing the cellulose blank3 into the forming cavity 6, as illustrated in figure 2b. When the first mould part5a is moving further into the forming cavity 6 and pushing the cellulose blank3 towards the bottom wall 9b, the deformation element 7 is configured so thatit is deformed when meeting the bottom wall 9b. The cellulose blank isarranged between the deformation element 7 and the bottom wall 9b, asillustrated in figure 2c. The deformation element 7 may also be designed andconfigured to deform in other ways if desired. The deformation element 7 is inthe forming step exerting a forming pressure PF on the cellulose blank 3 duringforming of the cellulose products 2, as shown in figure 2d. 17 ln figures 2b and 2c intermediate steps in the forming process are shown,where the cellulose blank 3 is pushed into the forming cavity 6 by thedeformation element 7. When the deformation element 7 is fully deformed, asshown in figure 2d, the forming of the cellulose product is taking place and themovement of the first mould part 5a in the pressing direction Dp towards thesecond mould part 5b is being stopped. When the forming of the celluloseproduct 2 from the cellulose blank 3 is completed, the first mould part 5a ismoved in a direction away from the second mould part 5b, opposite thepressing direction Dp. When the forming mould 4 is moved into the open state, the formed cellulose product 2 is removed from the forming mould 4.

As shown in figure 2d, the forming cavity 6 is formed and enclosed by the firstmould part 5a and the second mould part 5b during forming of the celluloseproducts 2. As described above, the forming cavity 6 is in this embodimentarranged in the second mould part 5b and delimited by the second side wall9a and the bottom wall 9b. During the forming process, the forming cavity 6 isfurther delimited by the lower surface 19c of the first mould part 5a, whereinthe forming cavity 6 is arranged as an enclosed volume in which thedeformation element 7 is deformed, as shown in figure 2d. Thus, duringforming of the cellulose products 2 the deformation element 7 is arranged inthe forming cavity 6 and exerting a forming pressure PF on the cellulose blank3. ln figure 3a, the forming mould 4 is shown in a view from above and in figure3b, a cross-sectional view from above of the forming mould 4 is shown. ln theschematically shown embodiment, the forming cavity 6, the first mould part 5a,and the second mould part 5b are having rectangular-like shapes. However,the forming cavity 6 and mould parts may have any desired shapes, such ascircular, oval, or other regular or other non-regular shapes, depending on theshape of the cellulose products 2 produced. lt should be understood that the forming mould 4 may have other designs and constructions compared to the ones described in the embodiment above. The 18 forming mould 4 may also for example be arranged with a cutting device,wherein the cellulose blank 3 is cut into a desired shape in the forming mould4 during the forming process. The deformation element may also be arrangedin the forming cavity 6 of the second mould part 5b. ln figures 5a and 5b, side views of production lines for the production ofcellulose products 2 from a cellulose blank 3 are schematically shown. Thecellulose blank 3 is dry-formed in a forming unit 13 from a pulp structure 20and the cellulose product 2 is formed in the forming mould system 1 comprisingthe forming mould 4. The forming unit 13 comprises a mill unit 14, a formingchamber 15, and a forming wire 16, where the forming chamber 15 furthercomprises a forming belt unit 17. The forming wire 16 is in this embodimentarranged in connection to the forming chamber 15, and the forming chamber15 is forming an at least partly enclosed volume above the forming wire 16.The formed cellulose blank 3 may be fon/varded to the forming mould 4 in acontinuous production flow, as illustrated in figure 5a, or alternatively arrangedin rolls for intermediate storage before being used in the forming mould 4, asillustrated in figure 5b. ln further non-illustrated alternative embodiments, theformed cellulose blank 3 may be arranged in sheets or blanks for intermediatestorage.

The mill unit 14 is arranged for separating fibres from the pulp structure 20 andfor distributing the separated fibres into the forming chamber 15. The pulpstructure 20 used may for example be bales, sheets, or rolls of fluff pulp, paperstructures, or other suitable cellulose fibre containing structures, that are fedinto the mill unit 14. The mill unit 14 may be of any conventional type, such asfor example a hammer mill or other type of pulp de-fiberizing machine, wherethe pulp structure 20 is fed into the mill unit 14 through an inlet opening 14a,and separated fibres are distributed to the forming chamber 15 through anoutlet opening 14b of the mill unit 14. A pipe or channel may if needed bearranged between the mill unit 14 and the forming chamber 15. 19 The forming wire 16 may be of any suitable conventional type, and may beformed as an endless belt structure with an inner belt side 16a and an outerbelt side 16b. The inner belt side 16a of the forming wire 16 may as an examplehave an extension that is essentially parallel to a horizontal plane. The innerbelt side 16a of the forming wire 16 is arranged in connection to the formingchamber 15. Alternatively, the inner belt side 16a may be arranged at an anglein relation to the horizontal plane. A first vacuum box 21 may be arranged inconnection to the inner belt side 16a of the forming wire 16 for controlling theflow of air in the forming chamber 15, and for distributing the separated fibresonto the inner belt side 16a. The first vacuum box 21 may for example bearranged below the inner belt side 16a of the forming wire 16. ln theembodiments shown in figures 7, 8a-c and 9a-b, the first vacuum box 21 issuitably arranged between the inner belt side 16a and the outer belt side 16b.A web structure, such as a cellulose tissue web structure or web structuresmade of other materials may first be arranged on the inner belt side 16a andtransported with the forming wire 16, wherein the separated fibres instead aredistributed onto the web structure arranged on the inner belt side 16a. ln thisway, the web structure is used as a carrier for the separated fibres and thecellulose blank 3 is formed onto the web structure. The web structure mayalternatively be arranged after an output section 18 of the forming chamber 15for supporting the formed cellulose blank 3.

The forming chamber 15 is arranged for distributing the separated fibres ontothe inner belt side 16a of the forming wire 16 for forming the cellulose blank 3.The forming chamber 15 is arranged as a hood structure or compartment inconnection to the forming wire 16. The forming chamber 15 is enclosing avolume in which the separated fibres are distributed from the mill unit 14 to theforming wire 16. The forming chamber 15 comprises in the embodimentsshown in figures 6, 7 and 8a-c, two side walls 15a, a rear wall 15b and a frontstructure 15d. The forming chamber may have other configurations if desireddepending on the design of the forming unit 13. The forming chamber 15further comprises the forming belt unit 17. ln the embodiment shown in figures 6, 7 and 8a-c, at least a part of the front structure 15d is constituted by theforming belt unit 17, and the forming belt unit 17 is in the embodiments shownarranged above the forming wire 16. The front structure 15d may also comprisea front wall section 15c arranged in connection to the forming belt unit 17. Theforming belt unit 17 may be arranged as an endless belt construction, with anouter belt side 17a and an inner belt side 17b. The inner belt side 17b isarranged inside the forming chamber 15 towards the forming wire 16 totransport the fibres in the forming chamber 15. The forming belt unit 17 isarranged at the output section 18 of the forming chamber 15, and the formingwire 16 and the forming belt unit 17 are transporting the separated fibrestowards the output section 18. The output section 18 is constituted by anopening between the forming belt unit 17 and the forming wire 16, where the cellulose blank 3 is fed out from the forming unit 13.

The forming belt unit 17 may suitably be formed as a wire structure andarranged with a second vacuum box 22 for controlling the flow of air in theforming chamber 15, and for a controlled distribution and formation of theseparated fibres towards the output section 18 of the forming chamber. Thesecond vacuum box 22 may suitably be arranged between the outer belt side17a and the inner belt side 17b. The second vacuum box 22 is thus arrangedin connection to the inner belt side 17b of the forming belt unit 17 for controllingthe flow ofair in the forming chamber15, and also for distributing the separated fibres onto the inner belt side 17b of the forming belt unit 17. ln an alternative embodiment, the forming belt unit 17 may be arranged as anendless belt construction without a vacuum box. The belt may then instead bemade from a suitable material, such as suitable rubber compounds, plastic materials, or metal structures.

An upper web structure, such as a cellulose tissue web or web structures madeof other materials may be arranged in connection to the inner belt side 17b ofthe forming belt unit 17 and transported with the forming belt unit 17. The upper web structure is thus arranged above the formed cellulose blank 3, and in this 21 way the upper web structure is used as a cover material for the cellulose blank3 formed by the separated fibres. The upper web structure may alternativelybe arranged after the output section 18 of the forming chamber 15. ln embodiments where the forming belt unit 17 is not covering the whole frontstructure 15d, as shown in figure 7, the front wall section 15c is preventingfibres from escaping from the forming chamber 15. The forming chamber 15may in an alternative embodiment be constructed with a forming belt unit 17covering the whole front structure 15d. As described above, the formingchamber 15 further comprises the output section 18 for the formed celluloseblank 3. As shown in figures 6, 7 and 8a-c, the forming belt unit 17 is arrangedin connection to the output section 18 of the forming chamber 15. The formingbelt unit 17 is thus arranged at the output section 18 of the forming chamber15, and the forming wire 16 and the forming belt unit 17 are transporting the separated fibres in the forming chamber 15 towards the output section 18.

The cellulose blank 3 is formed in the forming chamber through the interactionbetween the different components involved. The separated fibres from the millunit 14 are entering the forming chamber 15 and are falling down on the innerbelt side 16a of the forming wire 16. The forming wire 16 is transporting thefibres in the forming chamber in a transporting direction DT towards the outputsection 18. The forming belt unit 17 is also transporting the fibres in the formingchamber 15 in the transporting direction DT towards the output section 18,where the separated fibres also are distributed onto the inner belt side 17b ofthe forming belt unit 17. Through the interaction between the forming wire 16and the forming belt unit 17, an even distribution of fibres and formation of the cellulose blank 3 is achieved.

As shown in figures 6, 7, 8a-c, the forming wire 16 comprises the inner beltside 16a and the outer belt side 16b, where the inner belt side 16a is arrangedto transport the fibres in the forming chamber 15. The forming belt unit 17comprises the outer belt side 17a and the inner belt side 17b, where the inner belt side 17b is arranged to transport the fibres in the forming chamber 15. The 22 inner belt side 17b of the forming belt unit 17 is arranged at an angle oi inrelation to the inner belt side 16a of the forming wire 16, as illustrated in figure8b. Tests have shown that a suitable angle d is in the range 10°-80°, preferably20°-70°, and more preferably 30°-60°. With an angle oi in these ranges a desired formation of the cellulose blank 3 is achieved.

A gap section 19 is in the different embodiments formed in the transportingdirection DT where the inner belt side 17b of the forming belt unit 17 and theinner belt side 16a of the forming wire 16 are overlapping each other, as shownin figure 8b. The gap section 19 has a narrowing configuration towards theoutput section 18. The cellulose blank 3 is being formed from the separatedfibres in the gap section 19 when the forming wire 16 and the forming belt unit 17 are transporting the cellulose fibres towards the output section 18.

During forming of the cellulose blank 3 in the different embodiments described,the separated fibres are carried by air as carrying medium in the formingchamber 15. lf desired, the cellulose blank 3 may be compacted or compressed beforearranging the cellulose blank 3 in the forming mould 4 between the first mouldpart 5a and the second mould part 5b. As an example, a pair of compressionrollers may be arranged after the output section 18 of the forming chamber 15,as illustrated in figure 7, where a first compression roller 23 and a secondcompression roller 24 are cooperating to compact the cellulose blank 3. ln alternative embodiments shown in figures 8a-c, the cellulose blank 3 maybe compacted in the forming unit 13 directly in connection to the forming of thecellulose blank 3. A pair of compression rollers may for example be arrangedin connection to the output section 18. ln the embodiment shown in figures 8a-b, the forming belt unit 17 comprises an integrated first compression roller 23arranged at the output section 18. The forming belt unit may 17 comprise twoor more rollers for holding the forming belt or wire, and the roller arranged inconnection to the output section 18 is configured as the first compression roller 23 23. ln a similar way, the forming wire 16 may be arranged with a secondcompression roller 24, which is cooperating with the first compression roller 23to compact the formed cellulose blank 3. The second compression roller 24may be integrated in the structure of the forming wire 16. As shown in figures8a-b, the second compression roller 24 is arranged below the inner belt side16a of the forming wire 16 in connection to the output section 18. When theformed cellulose blank 3 is fed through the output section 18 between the firstcompression roller 23 and the second compression roller 24, the formedcellulose blank structure is compacted into a desired structure. The distancebetween the first compression roller 23 and the second compression roller 24may suitable be adjustable, wherein different compression rates can bechosen. The compression rollers may in a conventional way be flexiblyarranged through a spring suspension system or similar arrangement if desked. ln figure 8c, a further embodiment of the forming unit 13 is shown. The formingunit 13 in this embodiment has a similar configuration to the forming unit 13shown in figures 8a-b, but the forming wire 16 in the embodiment shown infigure 8c has a different layout. The forming wire 16 may comprise two or morerollers for holding the forming belt or wire, and the roller arranged in connectionto the output section 18 is configured as the second compression roller 24. Afurther conveyor belt may be arranged downstream the output section 18 forfurther transportation of the formed cellulose blank 3. ln an alternative configuration shown in figures 9a-b, the forming unit 13 forforming the cellulose blank 3 is arranged with a more compact design. Thisconfiguration is similar to the embodiment shown in figure 8c. The forming unit13 comprises a mill unit 14, a forming chamber 15, and a forming wire 16. Theforming chamber 15 may be arranged in connection to the forming wire 16,and the forming chamber 15 comprises a forming belt unit 17. The forming wire16 and the forming belt unit 17 are arranged, in the same way as described in relation to the embodiments above, at an angle d in relation to each other, as 24 illustrated in figure 9b. Tests have shown that the angle oi suitably is in therange 10°-80°, preferably 20°-70°, and more preferably 30°-60°. The formingwire 16 comprises an inner belt side 16a and an outer belt side 16b. The innerbelt side 16a is arranged to transport the fibres in the forming chamber 15. Theforming belt unit 17 comprises an outer belt side 17a and an inner belt side17b. The inner belt side 17b is arranged to transport the fibres in the formingchamber 15. A first vacuum box 21 is arranged in connection to the formingwire 16 for transporting air through the inner belt side 16a of the forming wire16. The forming belt unit 17 is in this embodiment arranged as a wire structure,and a second vacuum box 22 is arranged in connection to the forming belt unit17 for transporting air through the inner belt side 17b of the forming belt unit17. The mi|| unit 14 is arranged upstream the forming wire 16 and the formingbelt unit 17. A pulp structure 20 is fed into the mi|| unit 14 through an in|etopening 14a, and separated fibres from the mi|| unit 14 are as illustrated infigure 9a flowing towards the forming wire 16 and the forming belt unit 17 froman out|et opening 14b of the mi|| unit 14. The first vacuum box 21 and thesecond vacuum box 22 are arranged to direct the separated fibres towards theforming wire 16 and the forming belt unit 17. The forming belt unit 17 comprisesa first compression roller 23 arranged at an output section 18 of the formingunit 13, and the forming wire 16 comprises a second compression roller 24arranged at the output section 18. The first compression roller 23 and thesecond compression roller 24 are arranged to cooperate for compacting orcompressing the formed cellulose blank 3. ln a similar way as described in theembodiments above, the forming chamber is arranged for directing the flow ofseparated fibres towards the forming wire 16 and the forming belt unit 17. Theforming chamber 15 is forming an enclosed volume for the flow of separatedfibres preventing separated fibres from escaping to the surroundingenvironment. The forming chamber 15 in this embodiment comprises two sidewalls 15a, a front structure 15d, a first rear wall 15e, and a second rear wall15f. The front structure 15d may be constituted by the forming belt unit 17 anda front wall section 15c, as shown in figure 9a. With this arrangement of theforming unit 13 with the angular configuration of the forming wire 16 and the forming belt unit 17 in connection to the flow of separated fibres from the mi||unit 14 is providing a compact and efficient design of the forming unit 13. Anefficient forming of the cellulose blank 3 can thus be achieved with less spacecompared to a traditional web forming machine. A gap section 19 is formed inthe transporting direction DT where the inner belt side 17b of the forming beltunit 17 and the inner belt side 16a of the forming wire 16 are overlapping eachother, as shown in figure 9b. The gap section 19 has a narrowing configurationtowards the output section 18. ln the different embodiments, the forming wire 16 may be driven with a formingwire speed VFW for feeding the separated fibres in the transporting directionDT, and the forming belt unit 17 may be driven with a forming belt speed VFB,as illustrated in figures 8b and 9b. As described above, the forming wire 16 istransporting separated fibres in the forming chamber 15 towards the outputsection 18. Also the forming belt unit 17 is transporting separated fibres in theforming chamber 15 towards the output section 18. Through the transportationof fibres towards the output section 18 the cellulose blank 3 is formed. Toachieve a cellulose blank 3 with suitable properties, the forming belt speed VFBis equal to or greater than the forming wire speed VFvv. Test have shown thatwith these relationships between the speeds, a formation of the cellulose blankwith a desired homogenous structure is achieved. The forming belt speed VFBmay be chosen to be greater than the forming wire speed VFvv to avoid areas in the cellulose blank 3 with undesired fibre aggregations with higher densities.

After the formation of the cellulose blank 3, the cellulose blank is transportedto the forming mould 4, where the cellulose blank 3 is arranged in the formingmould 4 between the first mould part 5a and the second mould part 5b. Duringthe forming of the cellulose products, the cellulose blank 3 is heated to aforming temperature in the range of 100°C to 300°C. The cellulose products 2are formed from the cellulose blank 3 in the forming mould 4, by pressing theheated cellulose blank 3 with an isostatic forming pressure Piso in the range 1-100 MPa, preferably 4-20 MPa. The forming mould 4 comprises the forming 26 cavity 6 and the deformation element 7. The first mould part 5a and the secondmould part 5b are moved in relation to each other in the pressing direction Dp,and during forming of the cellulose products 2, the first mould part 5a and thesecond mould part 5b are pressed in relation towards each other duringforming of the cellulose products 2. During the pressing operation, the formingcavity 6 is formed and enc|osed by the first mould part 5a and the secondmould part 5b during forming of the cellulose products 2, and the deformationelement 7 is exerting the isostatic forming pressure Piso on the cellulose blank3 during forming of the cellulose products 2. During forming of the celluloseproducts 2, the deformation element 7 is arranged in the forming cavity 6. Thedeformation element 7 is arranged to establish a uniform pressure in alldirections in the forming mould 4 on the cellulose blank 3 through deformation,and the deformation element 7 is as described above during forming of thecellulose products 2 exerting the isostatic forming pressure Piso on thecellulose blank 3 in the range 1-100 MPa, preferably 4-20 MPa.

To achieve the desired properties of the cellulose products 2 in the differentembodiments described, the dry-formed cellulose blank 3 may have a drybasis weight in the range of 600-3000 g/m2. Within this dry basis weight range,the formed fibre structure constituting the cellulose blank 3 will have propertiessuitable for forming in the forming mould 4.

Further, in the different embodiments described, the forming unit 13 maycomprise a cellulose fibre recycling unit 25. The fibre recycling unit 25 isarranged for transporting residual cellulose blank fibre material 3a from theforming mould 4 to the mill unit 14. After forming of the cellulose products 2 inthe forming mould 4, there may be residual cellulose blank fibre material 3afrom the cellulose blank 3. With the fibre recycling unit 25, the residual orremaining cellulose fibres can be recycled and re-used for forming a newcellulose blank 3 together with fibres from the pulp structure 20. ln figure 5a,an example of a fibre recycling unit 25 is schematically illustrated. The fibre recycling unit 25 comprises a channel structure 26 for transporting the residual 27 cellulose blank fibre material 3a from the forming mould 4 to the mill unit 14.The residual cellulose blank fibre material 3a is also schematically illustratedin figure 1. The channel structure 26 comprises an inlet portion 28 arranged inconnection to the forming mould 4, and the residual material can be suckedinto the inlet portion 28 for further transportation to the mill unit 14. The mill unit14 may be arranged with a separate inlet structure for the residual material,where the separate inlet structure is connected to an outlet portion 29 of thechannel structure 26. The channel structure 26 may further be arranged witha suitable combined mill and fan unit 27, which is used for at least partlyseparate the residual material before further transportation to the outlet portion29 and the mill unit 14. ln the embodiments described above, the deformation element 7 is beingdeformed during the forming process, and the deformation element 7 is duringforming of the cellulose products 2 arranged to exert a forming pressure PF onthe cellulose blank 3. To exert a required forming pressure PF on the celluloseblank 3, the deformation element 7 is made of a material that can be deformedwhen a force or pressure is applied. For example, the deformation element 7can be made of an elastic material capable of recovering size and shape afterdeformation. The deformation element 7 may further be made of a materialwith suitable properties that is withstanding the high forming pressure andtemperature levels used when forming the cellulose products 2 in the forming mould 4.

During the forming process, the deformation element 7 is deformed to exertthe forming pressure PF on the cellulose blank 3. Through the deformation aneven pressure distribution can be achieved in the forming mould 4, even if thecellulose products 2 are having complex three-dimensional shapes withcutouts, apertures and holes, or if the cellulose blank 3 used is having varyingdensity, thickness, or grammage levels.

Certain elastic or deformable materials have fluid-like properties when being exposed to high pressure levels. lf the deformation element 7 is made of such 28 a material, an even pressure distribution in the forming mould 4 can beachieved in the forming process, where the pressure exerted on the celluloseblank 3 from the deformation element 7 is equal or essentially equal in alldirections in the forming mould 4. When the deformation element 7 duringpressure is in its fluid-like state, a uniform fluid-like pressure distribution isachieved in the forming mould 4. The forming pressure is with such a materialthus applied to the cellulose blank 3 from all directions, and the deformationelement 7 is in this way during the forming of the cellulose products 2 exertingthe isostatic forming pressure Piso on the cellulose blank 3, as illustrated witharrows in figure 4. The isostatic forming pressure Piso from the deformationelement 7 is establishing a uniform pressure in all directions in the formingmould 4 on the cellulose blank 3. The isostatic forming pressure Piso isproviding an efficient forming process of the cellulose products 2 in the formingmould 4, and the cellulose products 2 can be produced with high quality evenif having complex shapes.

As shown in figure 4, the second mould part 5b has an alternative configurationwith the inner side wall section 9b of the side wall 9 having a curved shape,and the deformation element 7 is exerting an isostatic forming pressure Pisoas described above on the cellulose blank 3 arranged in the forming mould 4between the deformation element 7 and the side wall section 9b and the innerwall section 10b of the bottom wall 10.

The deformation element 7 may be made of a suitable structure of elastomericmaterial, where the material has the ability to establish a uniform pressure onthe cellulose blank 3 in the forming mould 4 during the forming process. As anexample, the deformation element 7 is made of a massive structure or anessentially massive structure of silicone rubber, polyurethane,polychloroprene, or rubber with a hardness in the range 20-90 Shore A. Othermaterials for the deformation element 7 may for example be suitable gel materials, liquid crystal elastomers, and MR fluids. 29 As described above, the deformation element 7 is through deformation duringforming of the cellulose products 2 establishing a uniform pressure in alldirections in the forming mould 4 on the cellulose blank 3. The deformationelement 7 is during forming of the cellulose products 2 exerting an isostaticforming pressure Piso on the cellulose blank 3. A suitable isostatic formingpressure Plso when forming the cellulose products 2 is within the range 1-100MPa, preferably 4-20 MPa. ln the embodiments described above, the deformation element 7 may bereleasably attached to the first mould part 5a or the second mould part 5b. Thedeformation element 7 is shaped into a shape suitable for the forming mould4, wherein the deformation element 7 during the forming of the celluloseproduct 2 is enabling an efficient pressure distribution on the cellulose blank 3. ln an alternative embodiment, the deformation element 7 instead comprises aflexible membrane and a pressure media. With this construction, thedeformation element 7 during the forming of the cellulose product 2 is enablingan efficient pressure distribution on the cellulose blank 3. The deformationelement 7 may for example be arranged in connection to the first mould part5a and the pressure media may for example be hydraulic oil exerting apressure on the ﬂexible membrane during the forming of the cellulose products2. An outer part of the flexible membrane may for example be attached to alower surface of the first mould part 5a, wherein a sealed volume is formedbetween the flexible membrane, and the lower surface. The pressure mediamay be arranged to flow into and out from the sealed volume through a flowchannel arranged in the first mould part 5a. Through the pressure media, thedeformation element is exerting a forming pressure on the cellulose blank.During the forming process, the pressure media is allowed to flow into thesealed volume. ln this way, the flexible membrane is exerting the formingpressure on the cellulose blank 3 arranged in the forming cavity 6 of theforming mould 4 when being deformed. As described above, a suitable forming pressure PF when forming the cellulose products 2 is within the range 1-100 MPa, preferably 4-20 MPa. By applying a suitable pressure on the celluloseblank 3 with the flexible membrane, the cellulose fibres in the cellulose blank3 are compressed in the forming mould 4. The applied pressure on thecellulose blank 3 from the pressure media and the flexible membrane may beisostatic in order to compress the cellulose fibres evenly regardless of theirrelative position on the forming mould 4 and regardless of the actual localamount of fibres. The isostatic pressure from the deformation element 7 isestablishing a uniform pressure in all directions in the forming mould 4 on thecellulose blank 3. ln this way, an efficient forming of the cellulose products 2 isachieved, and the cellulose products 2 can be produced with high quality. Thepressure media and/or the forming mould parts may be heated to establish a suitable forming temperature.

The forming mould system 1 may comprise a fluid control device for thepressure media, and the fluid control device may be an actuator or similararrangement compressing and transporting the pressure media into the sealedvolume, and also transporting the pressure media out from the sealed volumeafter the forming process. The pressure media used in the forming process may be any suitable ﬂuid, such as for example hydraulic oil, water and air.

The forming mould system 1 in the embodiments described above is furthercomprising a heating device 10 arranged in relation to the first mould part 5aand/or the second mould part 5b. During forming of the cellulose products 2the first mould part 5a and/or the second mould part 5b is heated to a formingmould temperature in the range 100-500°C to establish the formingtemperature TF in the range of 100°C to 300°C that needs to be applied to thecellulose blank 3. The heating device may be integrated in the first mould part5a and/or the second mould part 5b, and suitable heating devices 10 are e.g.an electrical heater or a fluid heater in which a heated fluid medium is flowingin channels in the forming mould parts. Other suitable heat sources may alsobe used. 31 The forming mould system 1 in the embodiments described above is furthercomprising a pressing unit 11 arranged to apply a pressure on the first mouldpart 5a and/or the second mould part 5b. During forming of the celluloseproducts 2 the deformation element 7 is exerting a forming pressure PF on thecellulose blank 3 in the range 1-100 MPa, preferably 4-20 MPa. The pressingunit may also be used for displacing the first mould part 5a and/or the secondmould part 5b. The moving mould part or alternatively moving mould parts maybe disp|aced with a suitable pressing actuator, such as a hydraulic, pneumatic,or electric actuator. lt should be understood that the forming unit 13 and the forming mould system1 may have other orientations than the ones described and illustrated in thefigures. References to positions, such as above, below, upper and lower areused for clarification purposes and to describe the relative relationships between different parts involved. lt will be appreciated that the above description is merely exemplary in natureand is not intended to limit the present disclosure, its application or uses. Whilespecific examples have been described in the specification and illustrated inthe drawings, it will be understood by those of ordinary skill in the art thatvarious changes may be made and equivalents may be substituted forelements thereof without departing from the scope of the present disclosureas defined in the claims. Furthermore, modifications may be made to adapt aparticular situation or material to the teachings of the present disclosurewithout departing from the essential scope thereof. Therefore, it is intendedthat the present disclosure not be limited to the particular examples illustratedby the drawings and described in the specification as the best mode presentlycontemplated for carrying out the teachings of the present disclosure, but thatthe scope of the present disclosure will include any embodiments falling withinthe foregoing description and the appended claims. Reference signsmentioned in the claims should not be seen as limiting the extent of the matter 32 protected by the claims, and their sole function is to make claims easier tounderstand. 33 REFERENCE SIGNS 1: 3a: 5a:5b: 8a:8b:8c: 9a:9b:9c:10: 10a:10b: 11:12:13:14: 14a:14b: : 15a:15b:15c:15d: Forming mould system Cellulose product Cellulose blank Residual cellulose blank fibre materialForming mould First mould part Second mould part Forming cavity Deformation element First side wall, First mould partUpper surface, First mould partLower surface, First mould partSecond side wall, Second mould partOuter wall section, Second side walllnner wall section, Second side wallUpper wall section, Second side wallBottom wall, Second mould partOuter wall section, Bottom walllnner wall section, Bottom wallHeating device Pressing unit Forming unit Mill unit lnlet opening, Mill unit Outlet opening, Mill unit Forming chamber Side wall, Forming chamber Rear wall, Forming chamber Front wall section, Forming chamber Front structure, Forming chamber 15e: 15f:16: 16a:16b: 17: 17a:17b: 18:19:20:21:22:23:24:25:26:27:28:29: 34 First rear wall, Forming ChamberSecond rear wall, Forming chamberForming wire lnner belt side, Forming wireOuter belt side, Forming wireForming belt unit Outer belt side, Forming belt unitlnner belt side, Forming belt unitOutput section Gap section Pulp structure First vacuum box Second vacuum box First compression roller Second compression roller Fibre recycling unit Channel structure Mill and fan unit lnlet portion Outlet portion

Claims

1._ 1. A method for producing cellulose products (2) from a cellulose blank (3),wherein the method comprises the steps; dry-forming the cellulose blank (3) in a forming unit (13), whereinthe forming unit (13) comprises a mill unit (14), a forming chamber (15),and a forming wire (16) arranged in connection to the forming chamber(15), wherein the mill unit (14) is arranged for separating fibres from a pulpstructure (20) and distributing the separated fibres into the formingchamber (15), wherein the forming chamber (15) comprises a forming beltunit (17) arranged in connection to the forming wire (16), wherein theforming wire (16) and the forming belt unit (17) are arranged at an outputsection (18) of the forming chamber (15), wherein the forming wire (16)and the forming belt unit (17) are transporting the separated fibres towardsthe output section (18); arranging the cellulose blank (3) in a forming mould (4) betweena first mould part (5a) and a second mould part (5b); heating the cellulose blank (3) to a forming temperature in therange of 100°C to 300°C; and forming the cellulose products (2) from the cellulose blank (3) inthe forming mould (4), by pressing the heated cellulose blank (3) with anisostatic forming pressure (Piso) in the range 1-100 MPa, preferably 4-20MPa.

2. A method according to claim 1, wherein an inner belt side (17b) of the forming belt unit (17) isarranged at an angle (oi) in relation to an inner belt side (16a) of the formingwire (16), wherein a gap section (19) is formed between the inner belt side(17b) of the forming belt unit (17) and the inner belt side (16a) of theforming wire (16), wherein the gap section (19) has a narrowingconfiguration towards the output section (18), wherein the cellulose blank(3) is formed from the separated fibres in the gap section (19). 36

3. A method according to claim 2,wherein the angle (d) is in the range 10°-80°, preferably 20°-70°,and more preferably 30°-60°.

4. A method according to claim 2 or 3, wherein a first vacuum box (21) is arranged in connection to theinner belt side (16a) of the forming wire (16) for controlling the flow of airin the forming chamber (15), and for distributing the separated fibres ontothe inner belt side (16a) of the forming wire (16).

5. A method according to any of claims 2-4, wherein a second vacuum box (22) is arranged in connection tothe inner belt side (1 7b) of the forming belt unit (17) for controlling the flowof air in the forming chamber (15), and for distributing the separated fibresonto the inner belt side (17b) of the forming belt unit (17).

6. A method according to any of the preceding claims, wherein the method further comprises the steps: driving theforming wire (16) with a forming wire speed (VFvv); driving the forming beltunit (17) with a forming belt speed (VFB); wherein the forming wire (16) istransporting separated fibres in the forming chamber (15) towards theoutput section (18), and the forming belt unit (17) is transporting separatedfibres in the forming chamber (15) towards the output section (18).

7. A method according to claim 6,wherein the forming belt speed (VFB) is equal to or greater than the forming wire speed (VFw).

8. A method according to claim 6,wherein the forming belt speed (VFB) is greater than the forming wire speed (VFw). 12. 37 A method according to any of the preceding claims,wherein during forming of the cellulose blank (3), the separatedfibres are carried by air as carrying medium in the forming chamber (15). A method according to any of the preceding claims, wherein the forming mould comprises a forming cavity (6) and adeformation element (7), wherein the method further comprises the steps:moving the first mould part (5a) and the second mould part (5b) in relationto each other in a pressing direction (Dp); pressing the first mould part (5a)in relation to the second mould part (5b) towards each other during formingof the cellulose products (2), wherein the forming cavity (6) is formed andenclosed by the first mould part (5a) and the second mould part (5b) duringforming of the cellulose products (2), exerting the isostatic formingpressure (Piso) on the cellulose blank (3) by the deformation element (7)during forming of the cellulose products (2), wherein the deformationelement (7) during forming of the cellulose products (2) is arranged in theforming cavity (6). A method according to claim 10, wherein during forming of the cellulose products (2) thedeformation element (7) through deformation is arranged to establish auniform pressure in all directions in the forming mould (4) on the celluloseblank (3), wherein the deformation element (7) during forming of thecellulose products (2) is exerting an isostatic forming pressure (Piso) onthe cellulose blank (3) in the range 1-100 MPa, preferably 4-20 MPa. A method according to any of the preceding claims, wherein the method further comprises the step: compacting thecellulose blank (3) before arranging the cellulose blank (3) in the formingmould (4) between the first mould part (5a) and the second mould part(5b). 15. 38 A method according to claim 12, wherein the cellulose blank (3) is compacted in the forming unit(13) in connection to the output section (18), wherein the forming belt unit(17) comprises a first compression roller (23) arranged at the outputsection (18), wherein the forming wire (16) comprises a secondcompression roller (24) arranged at the output section (18), wherein thefirst compression roller (23) and the second compression roller arearranged to cooperate with each otherfor compacting the formed celluloseblank (3). A method according to any of the preceding claims,wherein the cellulose blank (3) is dry-formed to a fibre structurehaving a dry basis weight in the range of 600-3000 g/m2. A forming unit (13) for dry-forming a cellulose blank (3), wherein the forming unit (13) comprises a mill unit (14), a formingchamber (15), and a forming wire (16) arranged in connection to theforming chamber (15), wherein the mill unit (14) is arranged for separatingfibres from a pulp structure (20) and distributing the separated fibres intothe forming chamber (15), wherein the forming chamber (15) comprises aforming belt unit (17) arranged in connection to the forming wire (16),wherein the forming wire (16) and the forming belt unit (17) are arrangedat an output section (18) of the forming chamber (15), wherein the formingwire (16) and the forming belt unit (17) are transporting the separatedfibres towards the output section (18), wherein an inner belt side (17b) of the forming belt unit (17) isarranged at an angle (oi) in relation to an inner belt side (16a) of the formingwire (16), wherein a gap section (19) is formed between the inner belt side(17b) of the forming belt unit (17) and the inner belt side (16a) of theforming wire (16), wherein the gap section (19) has a narrowing configuration towards the output section (18). 39 16. Aforming unit (13) according to ciaim 15, wherein the angle (oi) is in the range 10°-80°, preferably 20°-70°,and more preferably 30°-60°. 5 17. Aforming unit (13) according to ciaim 15 or 16,wherein the forming unit (13) further comprises a cellulose fibrerecycling unit (25) arranged for transporting residual cellulose blank fibrematerial from a forming mould (4) to the mill unit (14).