Apparatus and method for dry manufacturing rigid cellulose products

Abstract

The present invention relates to a method and an apparatus for dry manufacturing rigid cellulose products, the apparatus comprising a moulding tool having a first mould part (16) and a second mould part (17), wherein each of the mould parts comprises a bottom surface (18a, 18b) and a wall surface (19a, 19b) and wherein at least one of the first mould part (16) and the second mould part (17) is displaceable in the axial direction in relation to the other in order to press the cellulose blank (11) between the mould parts into final shape by applying a predetermined pressure P in the axial direction of the moulding tool, at least one of the first mould part (16) and the second mould part (17) comprising a base body (20a, 20b), a top body (21a, 21b) and an intermediate ring body (22a, 22b), wherein the top body (21a, 21b) is displaceable in the axial direction in relation to the base body (20a, 20b) between an extended position and a compressed position, the ring body (22a, 22b) comprising at least a part of the wall surface (19a, 19b) of the mould part (16, 17), wherein the ring body (22a, 22b) is composed of an elastically deformable material, and wherein the ring body (22a, 22b) is configured to expand in the radial direction as a result of the top body (21a, 21b) being displaced from the extended position towards the compressed position. The apparatus is characterized in that the top body (21a, 21b) and the base body (20a, 20b) of said at least one mould part abut each other in the axial direction when the top body (21a, 21b) is in the compressed position and the ring body (22a, 22b) has a radially expanded shape.

Description

[0001] APPARATUS AND METHOD FOR DRY MANUFACTURING RIGID CELLULOSE PRODUCTS

[0002] Technical field of the Invention

[0003] The present invention relates in general to the field of method and apparatus for dry manufacturing of rigid cellulose products having non-flat general shape from a cellulose blank. The cellulose products may be used for packaging, storing, transporting and / or displaying other products such as electronics, tools, jewelry, food, dairy products, cosmetics, etc., and / or may be used as single / multiple use disposable articles. The method and apparatus are defined to provide rigid cellulose products having an undercut groove. The present invention also relates to such rigid cellulose product.

[0004] The apparatus comprises a moulding tool having a first mould part and a second mould part, wherein each of the mould parts comprises a bottom surface and a wall surface and wherein at least one of the first mould part and the second mould part is displaceable in the axial direction in relation to the other in order to press the cellulose blank between the bottom surfaces of the respective mould part and between the wall surfaces of the respective mould part into final shape by applying a predetermined pressure P in the axial direction of the moulding tool.

[0005] At least one of the first mould part and the second mould part comprises a base body, a top body and an intermediate ring body, wherein the top body is displaceable in the axial direction in relation to the base body between an extended position and a compressed position, the ring body comprising at least a part of the wall surface of the mould part, wherein the ring body is composed of an elastically deformable material, and wherein the ring body is configured to expand in the radial direction as a result of the top body being displaced from the extended position towards the compressed position. of the Invention

[0006] There are many situations where it is desirable to provide two-dimensional (2D) or three- dimensional (3D) shaped objects made of sustainable materials, such as biomaterials, instead of plastic / polymer materials. A biomaterial commonly used for packaging and disposable articles is wet moulded pulp based on cellulose fibres. Such wet moulded pulp has the advantage of being considered as a sustainable material, since it is produced from biomaterials and can be recycled after use. Wet moulded pulp comprises more or less only water and separated cellulose fibers, and consequently, wet moulded pulp has been popular to use for primary packaging applications (packaging next to the article), for secondary packaging applications (assembly of such primary packages), as well as for manufacturing of disposable articles / products.

[0007] One advantage of using wet-forming techniques is that one may easily manufacture rigid cellulose products having socalled undercut grooves in the wall sections, i.e. sub-features having negative shape / draft angles. These sub-features are for instance intended for securing a lid on a cup / tray, securing an article / object in a transport / display package, etc. However, a common disadvantage with all wet -forming techniques is the need for large amounts of water during the preparations of the cellulose pulp and the need for drying during the manufacturing / moulding of the cellulose product, which is a time and energy consuming step leading to low production speed and substantial high investment cost in machines and tooling. Meaning that the wet-forming techniques are not feasible to replace fossil-based alternatives neither in small nor large scale production of rigid cellulose products. Thereto, the aesthetical and mechanical properties of a wet-moulded cellulose product are hard to control with desirable precision, due to un-uniform cellulose pulp and due to the wet moulding manufacturing technique per se.

[0008] Therefore many actors / companies, starting a few decades ago, have changed their focus and investments towards dry-forming techniques wherein rigid cellulose products are manufactured from separated cellulose fibres that are introduced into a product forming unit in the shape of a cellulose blank / web, wherein the cellulose blank is moulded / formed into the shape of the intended cellulose product and wherein the cellulose fibres are bonded to each other using heat and pressure. The dry-forming techniques comprises different steps of generating an air-laid cellulose blank, that is fed into a product forming unit, i.e. thermo-forming press.

[0009] The technical field of dry manufacturing rigid cellulose products having non-flat general shape, such as trays, lids, or the like, i.e. wherein the forming / pressing is performed in one step using a moulding tool having a first / male mould part and a second / female mould part configured to cooperate with each other, is well known. However, the sub-technical field of dry manufacturing rigid cellulose products having non-flat general shape and an undercut groove, such as lids or the like, is still exposed to challenges.

[0010] WO 2023 / 110282 is directed towards the same technical field as the present invention and discloses a forming mould intended to generate undercut grooves in pressed cellulose products. The forming mould of WO 2023 / 110282 disclose that one of the mould parts, i.e. the male or the female mould part, comprises a first mould part section that is displaceable in the axial direction in relation to a base structure and comprises a second mould part section that is displaceable in the radial direction in response to said axial displacement of the first mould part section. It is described that the first mould part section due to the axial displacement thereof applies a predetermined forming pressure to the cellulose blank and that the second mould part section due to the radial displacement thereof applies the same predetermined forming pressure to the cellulose blank. However, said document clearly disclose that during the entire pressing / forming of the cellulose product the location of the first mould part section (top part) is floating / undefined in the axial direction in relation to the base structure. Thereby, there is no possibility to have control of the pressing force in the axial direction applied by the first mould part section or in the radial direction applied by the second mould part section, and it will be impossible have the same predetermined pressure applied in the axial direction as well as in the radial direction. Thus, according to WO 2023 / 110282 the applied pressure in the axial direction by the first mould part section is totally dependent on the material characteristics and shape of the second mould part section. Thereto, the material characteristics of the second mould part section will change over time due to deterioration. When not having total control of the applied press force, there is an immediate risk that the applied forming pressure in the radial and / or the axial direction will become too large, leading to an over-pressed cellulose product at some locations. The material characteristics of the final cellulose product will then fluctuate along the product and the cellulose product will be miss-coloured at locations being exposed to over-pressure and also risk becoming brittle at those locations.

[0011] Thus, there is still a need in the art for a reliable, cheap and unharmful dry-forming technique / process for dry manufacturing rigid cellulose products having non-flat general shape and an undercut groove. of the Invention

[0012] The present invention aims at obviating the aforementioned and other disadvantages and failings of previously known methods and apparatus for dry manufacturing rigid cellulose products, and at providing an improved method and apparatus for dry manufacturing rigid cellulose products having non-flat general shape and an undercut groove.

[0013] A primary object of the present invention is to provide an improved method and apparatus for dry forming / manufacturing rigid cellulose products having non-flat general shape and an undercut groove, wherein the environmental benefits as well as time and energy saving benefits of conventional dry-forming techniques are maintained. It is another object of the present invention to provide an improved method and apparatus for dry forming / manufacturing rigid cellulose products having non-flat general shape and an undercut groove, wherein the applied press forces to the cellulose blank are accurate in the axial direction as well as in the radial direction. It is another object of the present invention to perform the forming / pressing of the solid cellulose product having an undercut groove in a single pressing operation / motion.

[0014] Summary of the Invention

[0015] According to the invention at least the primary object is attained by means of the initially defined apparatus and method having the features defined in the independent claims. Preferred embodiments of the present invention are further defined in the dependent claims.

[0016] According to a first aspect of the present invention, there is provided an apparatus of the initially defined type wherein the top body and the base body of said at least one mould part abut each other in the axial direction when the top body is in the compressed position and the ring body has a radially expanded shape.

[0017] According to a second aspect of the present invention, there is provided a method for dry manufacturing rigid cellulose products having essentially non-flat general shape from a cellulose blank using an apparatus as defined herein above, wherein the method comprises the steps of: - providing the cellulose blank into the moulding tool between the first mould part and the second mould part,

[0018] - displacing at least one of the first mould part and the second mould part in the axial direction in relation to each other and towards each other,

[0019] - expanding the ring body in the radial direction by displacing the top body from the extended position towards the compressed position, and

[0020] - abutting the top body and the base body of said at least one mould part in the axial direction when the top body reaches the compressed position, whereby the ring body has radially expanded shape.

[0021] Thus, the present invention is based on the insight that it is of uttermost importance to have control of the press forces in the axial direction as well as in the radial direction when having mould part displacements in both the axial and the radial directions during the forming / pressing of the rigid cellulose product. Thus, the inventors have realized that the displacement of the top body of the mould part has to be controlled by direct contact / abutment with the base body at the point of pressing / forming the cellulose product, and thereto the direct contact / abutment between the top body and the base body in the axial direction entails precise and controlled expansion of the ring body in the radial direction.

[0022] The present invention provides the advantage that all surfaces of the rigid cellulose product are pressed using predetermined and optimal pressing force. The present invention also provides the advantage that the forming / pressing is perform using a single pressing operation / motion, whereby obtaining a time and energy efficient forming of solid cellulose products having undercut groove.

[0023] According to various example embodiments of the present invention the first mould part is a male mould part and comprises a base body, a top body and an intermediate ring body, wherein the top body of the first mould part comprises the bottom surface of the first / male mould part, and wherein the ring body is configured to expand outwards in the radial direction as a result of the top body of the first / male mould part being displaced from the extended position towards the compressed position. Thereby the rigid cellulose product will obtain an outwardly bulging formation / feature at the wall of the cellulose product, wherein such undercut groove may be used to accommodate an upper rim of a cup / tray.

[0024] According to various example embodiments of the present invention the second mould part is a female mould part and comprises a base body, a top body and an intermediate ring body, wherein the base body of the second mould part comprises the bottom surface of the second mould part, and wherein the ring body is configured to expand inwards in the radial direction as a result of the top body of the second mould part being displaced from the extended position towards the compressed position. Thereby the rigid cellulose product will obtain an inwardly bulging formation / feature at the wall of the cellulose product, wherein such undercut groove may be used to snap over an upper rim of a cup / tray. According to a third aspect of the present invention, there is also provided a rigid cellulose product manufactured by said inventive method and apparatus.

[0025] Further advantages with and features of the invention will be apparent from the following detailed description of preferred embodiments.

[0026] Brief description of the drawings

[0027] A more complete understanding of the abovementioned and other features and advantages of the present invention will be apparent from the following detailed description of preferred embodiments in conjunction with the appended drawings, wherein:

[0028] Fig. 1 is a schematic illustration of a production line or apparatus for dry manufacturing rigid cellulose products,

[0029] Fig. 2 is a schematic illustration from the side of a set constituted by a tray and a rigid cellulose product in the shape of a lid, the figure is partly in cross section,

[0030] Fig. 3 is a schematic illustration of an inventive moulding tool according to a first embodiment, wherein a cellulose blank is provided into the moulding tool and wherein the male mould part comprises an elastically deformable ring body,

[0031] Fig. 4 is a schematic illustration of the moulding tool according to figure 3 during forming / pressing of the cellulose product,

[0032] Fig. 5 is a schematic illustration of the moulding tool according to figures 3 and 4 after the forming / pressing step and the cellulose product is released from the moulding tool,

[0033] Fig. 6 is a schematic illustration of an inventive moulding tool according to a second embodiment, wherein a cellulose blank is provided into the moulding tool and wherein the female mould part comprises an elastically deformable ring body,

[0034] Fig. 7 is a schematic illustration of the moulding tool according to figure 6 during forming / pressing of the cellulose product,

[0035] Fig. 8 is a schematic illustration of the moulding tool according to figures 6 and 7 after the forming / pressing step and the cellulose product is released from the moulding tool,

[0036] Fig. 9 is a schematic illustration of an inventive moulding tool according to a third embodiment, wherein a cellulose blank is provided into the moulding tool and wherein the male mould part comprises an elastically deformable ring body and the female mould part comprises an elastically deformable ring body,

[0037] Fig. 10 is a schematic illustration of the moulding tool according to figure 9 during forming / pressing of the cellulose product, and

[0038] Fig. 11 is a schematic illustration of the moulding tool according to figures 9 and 10 after the forming / pressing step and the cellulose product is released from the moulding tool. Detailed ion of embodiments of the invention

[0039] As used herein, the term "air / dry moulding / forming or air / dry laying / laid" means a well- known method according to which separated cellulose fibres are formed into a cellulose blank / sheet.

[0040] In air-laying technique, small / short fibres having a normal length in the range of 0,5 to 70 mm, for instance 1 to 50 mm, are separated and captured by an air stream / flow, and then laid on / applied to a forming mesh / surface, usually using an under-pressure at the other side of the mesh / surface. The general terms "air / dry laying" and "air / dry moulding" are used interchangeably herein. The cellulose fibre carrying air flow may be generated by suitable device located upstream and / or downstream the forming mesh / surface.

[0041] Reference is initially made to figures 1-2, wherein figure 1 disclose a schematic illustration of a generic production line / apparatus for dry manufacturing rigid cellulose products, generally designated 1. The production line 1 is configured for manufacturing rigid cellulose products, generally designated 2, having essentially non-flat general shape from separated cellulose fibres. Such a production line 1 may be arranged and set-up according to different well-known ways.

[0042] Figure 2 disclose a set constituted by a container / tray / cup 3 and a rigid cellulose product 2 in the shape of a lid, wherein the lid is formed using the inventive method. The container 3 comprises a container wall 4 and an opening 5 defined by a circumferential rim / brim 6 of the container wall 4. According to figure 2 embodiment the rim 6 has an essentially round cross- sectional area, however it shall be pointed out that the cross-section of the rim 6 may have other shapes. The container wall 4 may be cylindrical and have a circular cross section in the radial plane, like a tin can or a tube for crisps. The container 3 may have truncated cone shape having straight wall 4, narrowing in the direction away from the opening 5, in accordance with figure 2 embodiment, or may have complete cone shape. The container 3 may for instance have curvedshaped wall 4 seen in the axial plane. By having inclined container walls 4 multiple containers 3 are stackable one inside the other when they are empty, like mugs / cups / trays. The cross section of the container wall 4 in the radial plane may have any suitable shape, circular, oval, rectangular, polygonal, etc., and may differ in shape and / or dimension along the axial extension of the container 3. The rim 16 is preferably circular in order to simplify the attachment of the lid 2.

[0043] The container 3 may comprise a fixed bottom 7, or may be open in both axial ends, i.e. having two opposite openings 5, like a tube for posters. The bottom 7 may be located at the very lower end of the container wall 4, according to figure 2 embodiment, or be located at a distance from the lower end of the container wall 4, or a combination thereof. According to the disclosed embodiments, the circular outer rim surface of the rim 6 of the container 3 is located radially outside the envelope surface of the container wall 4. The container 3 may be made of any suitable and rigid material or combination of materials, such as cellulose, paperboard, metal, glass, plastic, etc. The container 3 may also be made of an inventive solid cellulose product 2. Cellulose raw material 8 is provided to the production line, and is fed to a separating / disintegrating unit 9 in order to obtain individualized / separated cellulose fibres. The separated cellulose fibres are thereafter transported by an air stream / flow to a dispenser of a cellulose blank / sheet forming unit 10. The cellulose fibres are laid by the dispenser on a moving or stationary perforated surface of the cellulose blank forming unit 10. The cellulose fibre carrying air flow may be generated by suitable device located upstream and / or downstream the perforated surface. Thereafter the generated cellulose blank, generally designated 11, is transported / transferred to a product forming unit 12, whereby rigid cellulose products 2 are formed and discharged from the product forming unit 12.

[0044] The cellulose blank forming unit 10 may be configured to generate a continuous cellulose blank 11 and / or discontinuous / discrete cellulose blanks 11. Preferably discontinuous / discrete cellulose blanks 11 are fed into the product forming unit 12.

[0045] The cellulose raw material 8 may be in the form of reeled pulp or paper, bale of cellulose pulp, paper, etc. and / or sheets of paper, cellulose pulp, etc. In case said cellulose raw material 8 is in the form of sheets and / or reeled pulp or paper, it can be fed directly into the separating unit 9. However, in case said cellulose raw material 8 is in the form of a bale or compact stacks of sheets, etc. one or more shredders and / or one or more additional separating / disintegrating units 9 may be necessary to be used for separating and dosing said cellulose raw material 8 from said bale or sheets in smaller quantities. The shredder(s) prepare cellulose raw material 8 to be accepted by said separating unit 9. The separating unit 9 disintegrates the cellulose raw material 8 into separated cellulose fibres. Said one or plurality of shredder(s) are arranged before said one or a plurality of separating unit(s) 9, so that an output of one of said shredder is connected to an input of one of said separating units 9. The shredders may be arranged in parallel to each other or in series with each other, and the disintegrating units 5 may be arranged in parallel to each other or in series with each other. The shredders and the disintegrating units 9 together constitute a cellulose fibre separating unit, arranged upstream the cellulose blank forming unit 10.

[0046] Said cellulose raw material 8 may be constituted by virgin cellulose fibres and / or recycled cellulose fibres and may originate from wood pulps such as kraft pulp, sulphite pulp, mechanical pulp, thermomechanical pulp (TMP), chemical treated mechanical pulp, chemi-thermomechanical pulp (CTMP), and / or from non-wood pulps such as bagasse, bamboo, abaca, hemp, flax, cotton.

[0047] The separating unit 9 may according to various embodiments be constituted by a hammer mill. In said separating unit 9 the cellulose raw material is separated into fibres having a normal length in the range of 0,5-70 mm. The length of said fibres may be customized by adjusting the internal properties of the separating unit 9 and / or by choosing a different separating unit 9 and / or choosing different cellulose raw material. The fibre length for wood pulp is according to various embodiments in the range 0,5-4 mm, preferably in the range 1,7-3, 6 mm. According to various embodiments the fibre length for non-wood pulp is in the range 0,5-70 mm. The production line 1 may comprise a pre-compression and / or imprinting unit 13, located downstream the cellulose blank forming unit 10 and upstream the product forming unit 12. In the pre-compression and / or imprinting unit 13, an air-laid fluffy cellulose blank 11 having a first thickness may be compressed into a cellulose blank 11 having a second thickness, wherein said second thickness is thinner than said first thickness, and / or may be provided with an imprinting pattern. During the pre-compression / imprinting the cellulose blank is made more coherent and easier to handle, since the pre-compression / imprinting generates internal bindings between individual cellulose fibres preventing mutual separation of the cellulose fibres.

[0048] The product forming unit 12 comprises a press unit 14, and may optionally comprise a preheating unit 15 arranged upstream the press unit 14. According to various example embodiments said cellulose blank 11 may be heated to an elevated temperature before being fed into the press unit 14 of the product forming unit 12. In such embodiment(s) where the cellulose blank 11 is preheated before being fed into the press unit 14, said press unit 14 may or may not comprise heating. According to various example embodiment said press unit 14 may be a heated press unit 14 for heating said cellulose blank 11 during pressing. In the case of a heated press unit 14, preheating of said cellulose blank 11 using a pre-heating unit 15 is optional. According to various example embodiments preheating of the cellulose blank 11 in said pre-heating unit 15 may be combined with a heated press unit 14. Having a pre-heating unit 15 in combination with a heated press unit 14 will speed up the manufacturing process in the product forming unit 12, and improve the quality / rigidity of the final rigid cellulose product 2. In the product forming unit 12 the cellulose blank 11 is heated to a temperature in the range 120 - 200 °C in order to obtain adequate rigidity and strength in the final cellulose product 2.

[0049] Reference is now made to figures 3-11, disclosing three example embodiments of the present invention. Common for the three example embodiments is that the press unit 14 comprises a moulding tool having a first mould part 16 and a second mould part 17, wherein at least one of the first mould part 16 and the second mould part 17 is / are displaceable in the axial direction in relation to the other, i.e. reciprocating back and forth in relation to each other in the axial direction, in order to exert pressure to the cellulose blank 11 loaded therebetween. In the figures the mutual displacement is disclosed as being vertical, however the mutual displacement may be horizontal or any other suitable angle. The cellulose blank 11 loaded into the moulding tool, is preferably constituted by an air-laid cellulose blank. The cellulose blank 11 may be generated upstream the product forming unit 12 in the same apparatus / production line and provided / transferred to the product forming unit 12, or may be generated at a separate location and provided / transferred to the product forming unit 12 via intermediate handling and storage.

[0050] Each of the first mould part 16 and the second mould part 17 comprise a bottom surface 18a, 18b and a wall surface 19a, 19b, wherein the cellulose blank 11 is pressed between the bottom surfaces 18a, 18b of the respective mould part and between the wall surfaces 19a, 19b of the respective mould part into final shape by applying a predetermined pressure P in the axial direction of the moulding tool.

[0051] According to various embodiments the second mould part 17 of the moulding tool is a female mould part, i.e. having a main recess for receiving the cellulose blank 11, and the first mould part 16 of the moulding tool is a male mould part, i.e. having a main projection for cooperation with said recess of the female mould part by being inserted therein, such that during the pressing / forming step the cellulose blank 11 is pressed into a final rigid non-flat shape, which may be any conceivable non-flat design / shape. It shall be pointed out that according to various embodiments, the male mould part 16 is located above the female mould part 17.

[0052] Radially outside the final rigid cellulose product 2, the cellulose blank 11 comprises a scrap area intended to be cut off during the pressing of the cellulose product 2 or after the pressing of the cellulose product 2. The scrap area may be left entirely uncompressed in the moulding tool, be partially compressed by applying a predetermined partial pressure less than said predetermined pressure P, or be fully compressed by applying said predetermined pressure P.

[0053] The predetermined pressure P is in the range 40-10000N / cm2, preferably in the range 100- 4000N / cm2. According to various embodiments said predetermined pressures are above 1000 N / cm2, and according to various embodiments said predetermined pressures are below 2500 N / cm2. The holding time during the pressing step is in equal to or more than 0,5 seconds and equal to or less than 10 seconds, preferably less than 5 seconds, and most preferably less than 3 seconds.

[0054] Reference is now especially made to figures 3-5, schematically disclosing a first example embodiment of the moulding tool. In this embodiment, the first / male mould part 16 comprises a base body 20a, a top body 21a and an intermediate ring body 22a, wherein the top body 21a is displaceable back and forth in the axial direction in relation to the base body 20a between an extended / unloaded position (figures 3 and 5) and a compressed / loaded position (figure 4). Thus, the first / male mould part 16 has less axial extension when the top body 21a is in the compressed position than when the top body 21a is in the extended position.

[0055] The ring body 22a comprises at least a part of the wall surface 19a of the first / male mould part 16, wherein the ring body 22a is composed of an elastically deformable material, and wherein the ring body 22a is configured to expand outwards in the radial direction as a result of the top body 21a being displaced from the extended position towards the compressed position.

[0056] When the projection of the first / male mould part 16 is inserted into the recess of the second / female mould part 17, the top body 21a is in the extended position in relation to the base body 20a by means of the ring body 22a. Eventually the bottom surface 18a of the first / male mould part 16 starts to engage the bottom surface 18b of the second / female mould par 17 via the semi-compressed cellulose blank 11 whereby the relative axial movement between the top body 21a of the first / male mould part 16 and the second / female mould part 17 decrease in speed. At the same time the relative axial movement between the base body 20a of the first / male mould part 16 and the second / female mould part 17 continues, whereby the ring body 22a becomes compressed in the axial direction between the top body 21a and the base body 20a and starts to expand in the radial direction.

[0057] The top body 21a and the base body 20a of the first / male mould part 16 abut / contact each other in the axial direction when the top body 21a is in the compressed position and the ring body 22a has a radially expanded shape, i.e. bulges radially outwards. At this moment the ring body 22a has a well-defined radial expansion, i.e. well-defined pressure in the radial direction, and the top body 21a provides a well-defined axial pressure to the cellulose blank 11 thanks to the inventive axial abutment between the base body 20a and the top body 21a of the first / male mould part 16.

[0058] When the first and second mould parts of the moulding tool are retracted from each other, the first / male mould part 16 will return to its original shape / form, i.e. the ring body 22a is relieved and the top body 21a returns to the extended position.

[0059] According to various embodiments, the top body 21a of the first / male mould part 16 comprises at least a part of the wall surface 19a of the first mould part 16. Thus, the ring body 22a is located at a distance from the bottom surface 18a of the first mould part 16, and thereby the generated undercut groove 23 in the cellulose product 2 is in the axial direction located a distance from a bottom portion 24 of the final cellulose product 2.

[0060] According to various embodiments, the base body 20a of the first / male mould part 16 comprises at least a part of the wall surface 19a of the first mould part 16, and thereby the generated undercut groove 23 in the cellulose product 2 is in the axial direction located a distance from a rim 25 of the final cellulose product 2.

[0061] The rigid cellulose product 2 having essentially non-flat general shape and generated by the inventive method comprises said bottom portion 24 and a wall 28 connected to and extending in the axial direction from the bottom portion 24, wherein the wall 28 comprises the circumferential undercut groove 23.

[0062] According to various embodiments, the wall surface 19b of the second / female mould part 17 comprises a recess 26 configured to cooperate with the ring body 22a of the first / male mould part 16 when the top body 21a of the first mould part 16 is located in the compressed position and the ring body 22a is radially expanded.

[0063] Reference is now especially made to figures 6-8, schematically disclosing a second example embodiment of the moulding tool. In this embodiment, the second / female mould part 17 comprises a base body 20b, a top body 21b and an intermediate ring body 22b, wherein the top body 21b is displaceable in the axial direction in relation to the base body 20b between an extended / unloaded position (figures 6 and 8) and a compressed / loaded position (figure 7). Thus, the second / female mould part 17 has less axial extension when the top body 21b is in the compressed position than when the top body 21b is in the extended position.

[0064] The ring body 22b comprises at least a part of the wall surface 19b of the second / female mould part 17, wherein the ring body 22b is composed of an elastically deformable material, and wherein the ring body 22b is configured to expand inwards in the radial direction as a result of the top body 21b being displaced from the extended position towards the compressed position.

[0065] When the projection of the first / male mould part 16 is inserted into the recess of the second / female mould part 17, the top body 21b is in the extended position in relation to the base body 20b by means of the ring body 22b. Eventually the top body 21b of the second / female mould part 17 starts to engage the base body 20a of the first / male mould par 16 via the semicompressed cellulose blank 11 whereby the relative axial movement between the top body 21b of the second / female mould part 17 and the first / male mould part 16 decrease in speed. At the same time the relative axial movement between the base body 20b of the second / female mould part 17 and the first / male mould part 16 continues, whereby the ring body 22b becomes compressed in the axial direction between the top body 21b and the base body 20b and starts to expand in the radial direction.

[0066] The top body 21b and the base body 20b of the second / female mould part 17 abut / contact each other in the axial direction when the top body 21b is in the compressed position and the ring body 22b has a radially expanded shape, i.e. bulges radially inwards. At this moment the ring body 22b has a well-defined radial expansion, i.e. well-defined pressure in the radial direction, and the base body 20b provides a well-defined axial pressure to the cellulose blank 11 thanks to the axial abutment between the base body 20b and the top body 21b of the second / female mould part 17.

[0067] When the first and second mould parts of the moulding tool are retracted from each other, the second / female mould part 17 will return to its original shape / form, i.e. the ring body 22b is relieved and the top body 21b returns to the extended position.

[0068] According to alternatives, the top body 21b of the second / female mould part 17 comprises at least a part of the wall surface 19b of the second mould part 17. Thus, the ring body 22b is located at a distance from the bottom surface 18b of the second mould part 17, and thereby the generated undercut groove 23 in the cellulose product 2 is in the axial direction located a distance from the bottom 24 of the final cellulose product 2.

[0069] According to various embodiments, the base body 20b of the second / female mould part 17 comprises at least a part of the wall surface 19b of the second mould part 17, and thereby the generated undercut groove 23 in the cellulose product 2 is in the axial direction located a distance from a rim 25 of the final cellulose product 2.

[0070] According to various embodiments, the wall surface 19a of the first / male mould part 16 comprises a recess 27 configured to cooperate with the ring body 22b of the second / female mould part 17 when the top body 21b of the second mould part 17 is located in the compressed position and the ring body 22b is radially expanded.

[0071] Reference is now especially made to figures 9-11, schematically disclosing a third example embodiment of the moulding tool. This embodiment is a combination of the above-mentioned first and second example embodiments. Thus, the first / male mould part 16 comprises a base body 20a, a top body 21a and an intermediate ring body 22a, wherein the top body 21a is displaceable in the axial direction in relation to the base body 20a between an extended / unloaded position and a compressed / loaded position, and the second / female mould part 17 also comprises a base body 20b, a top body 21b and an intermediate ring body 22b, wherein the top body 21b is displaceable in the axial direction in relation to the base body 20b between an extended / unloaded position and a compressed / loaded position. The teaching above referring to figures 3-8 is also applicable to the third example embodiment.

[0072] According to the third example embodiment, the top body 21a and the base body 20a of the first / male mould part 16 abut / contact each other in the axial direction when the top body 21a is in the compressed position and the ring body 22a has a radially expanded shape, i.e. bulges radially outwards. Thereto, the top body 21b and the base body 20b of the second / female mould part 17 abut / contact each other in the axial direction when the top body 21b is in the compressed position and the ring body 22b has a radially expanded shape, i.e. bulges radially inwards.

[0073] Thereby, the radial expansion of the respective ring body 22a, 22b may be made less in relation to the embodiments having a single ring body, whereby the risk of having the final cellulose product 2 stuck on the projection of the male mould part 16 or in the recess of the female mould part 17 is decreased. The use of a two deformable ring bodies 22a, 22b increase the freedom when designing the final cellulose products 2.

[0074] Thus, according to the invention at least one of the first mould part 16 and the second mould part 17 comprises a base body 20a, 20b, a top body 21a, 21b and an intermediate ring body 22a, 22b, wherein the top body 21a, 21b is displaceable in the axial direction in relation to the base body 20a, 20b between an extended position and a compressed position. The ring body 22a, 22b comprises at least a part of the wall surface 19a, 19b of the respective mould part 16, 17, wherein the ring body 22a, 22b is composed of an elastically deformable material, and wherein the ring body 22a, 22b is configured to expand in the radial direction as a result of the top body 21a, 21b being displaced from the extended position towards the compressed position. The top body 21a, 21b and the base body 20a, 20b of said at least one mould part 16, 17 abut / contact each other in the axial direction when the top body 21a, 21b is in the compressed position and the ring body 22a, 22b has a radially expanded shape.

[0075] In all embodiments it is preferred that the base body 20a, 20b and the top body 21a, 21b of the first mould part 16 and of the second mould part 17 are made of metal, for instance steel and / or aluminium.

[0076] Feasible modifications of the Invention

[0077] The invention is not limited only to the embodiments described above and shown in the drawings, which primarily have an illustrative and exemplifying purpose. This patent application is intended to cover all adjustments and variants of the preferred embodiments described herein, thus the present invention is defined by the wording of the appended claims and the equivalents thereof. Thus, the equipment may be modified in all kinds of ways within the scope of the appended claims.

[0078] Throughout this specification and the claims which follows, unless the context requires otherwise, the word "comprise", and variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or steps or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

Claims

Claims1. Apparatus for dry manufacturing rigid cellulose products (2) having essentially non-flat general shape from a cellulose blank (11), the apparatus (1) comprising a moulding tool having a first mould part (16) and a second mould part (17), wherein each of the mould parts comprises a bottom surface (18a, 18b) and a wall surface (19a, 19b) and wherein at least one of the first mould part (16) and the second mould part (17) is displaceable in the axial direction in relation to the other in order to press the cellulose blank (11) between the bottom surfaces (18a, 18b) of the respective mould part and between the wall surfaces (19a, 19b) of the respective mould part into final shape by applying a predetermined pressure P in the axial direction of the moulding tool,- at least one of the first mould part (16) and the second mould part (17) comprising a base body (20a, 20b), a top body (21a, 21b) and an intermediate ring body (22a, 22b), wherein the top body (21a, 21b) is displaceable in the axial direction in relation to the base body (20a, 20b) between an extended position and a compressed position,- the ring body (22a, 22b) comprising at least a part of the wall surface (19a, 19b) of the mould part (16, 17), wherein the ring body (22a, 22b) is composed of an elastically deformable material, and wherein the ring body (22a, 22b) is configured to expand in the radial direction as a result of the top body (21a, 21b) being displaced from the extended position towards the compressed position, characterized in that:- the top body (21a, 21b) and the base body (20a, 20b) of said at least one mould part abut each other in the axial direction when the top body (21a, 21b) is in the compressed position and the ring body (22a, 22b) has a radially expanded shape.

2. The apparatus according to claim 1, wherein the first mould part (16) is constituted by a male mould part and the second mould part (17) is constituted by a female mould part.

3. The apparatus according to claim 2, wherein the first / male mould part (16) comprises a base body (20a), a top body (21a) and an intermediate ring body (22a), wherein the top body (21a) of the first mould part (16) comprises the bottom surface (18a) of the first mould part (16), and wherein the ring body (22a) is configured to expand outwards in the radial direction as a result of the top body (21a) of the first mould part (16) being displaced from the extended position towards the compressed position.

4. The apparatus according to claim 2 or 3, wherein the second / female mould part (17) comprises a base body (20b), a top body (21b) and an intermediate ring body (22b), wherein the base body (20b) of the second mould part (17) comprises the bottom surface (18b) of the second mould part (17), and wherein the ring body (22b) is configured to expand inwards in the radial direction as aresult of the top body (21b) of the second mould part (17) being displaced from the extended position towards the compressed position.

5. The apparatus according to claim 3, wherein the top body (21a) of the first / male mould part(16) comprises at least a part of the wall surface (19a) of the first mould part (16).

6. The apparatus according to claim 3 or 5, wherein the base body (20a) of the first / male mould part (16) comprises at least a part of the wall surface (19a) of the first mould part (16).

7. The apparatus according to claim any of claims 3 and 5-6, wherein the wall surface (19b) of the second / female mould part (17) comprises a recess (26) configured to cooperate with the ring body (22a) of the first / male mould part (16) when the top body (21a) of the first mould part (16) is located in the compressed position.

8. The apparatus according to any of claims 3 and 5-7, wherein the base body (20a) and the top body (21a) of the first / male mould part (16) are made of metal.

9. The apparatus according to claim 4, wherein the top body (21b) of the second / female mould part (16) comprises at least a part of the wall surface (19b) of the second mould part (17).

10. The apparatus according to claim 4 or 9, wherein the base body (20b) of the second / female mould part (17) comprises at least a part of the wall surface (19b) of the second mould part (17).

11. The apparatus according to any of claims 4 and 9-10, wherein the wall surface (19a) of the first / male mould part (16) comprises a recess (27) configured to cooperate with the ring body (22b) of the second / female mould part (17) when the top body (21b) of the second mould part(17) is located in the compressed position.

12. The apparatus according to any of claims 4 and 9-11, wherein the base body (20b) and the top body (21b) of the second / female mould part (17) are made of metal.

13. The apparatus according to any preceding claim, wherein the cellulose blank (11) is composed of an air-laid cellulose blank.

14. A method for dry manufacturing rigid cellulose products (2) having essentially non-flat general shape from a cellulose blank (11) using a moulding tool having a first mould part (16) and a second mould part (17), wherein each of the mould parts comprises a bottom surface (18a, 18b) and a wall surface (19a, 19b) and wherein at least one of the first mould part (16) and the secondmould part (17) is displaceable in the axial direction in relation to the other in order to press the cellulose blank (11) between the bottom surfaces (18a, 18b) of the respective mould part and between the wall surfaces (19a, 19b) of the respective mould part into final shape by applying a predetermined pressure P in the axial direction of the moulding tool,- at least one of the first mould part (16) and the second mould part (17) comprising a base body (20a, 20b), a top body (21a, 21b) and an intermediate ring body (22a, 22b), wherein the top body (21a, 21b) is displaceable in the axial direction in relation to the base body (20a, 20b) between an extended position and a compressed position,- the ring body (22a, 22b) comprising at least a part of the wall surface (19a, 19b) of the mould part, wherein the ring body (22a, 22b) is composed of an elastically deformable material, and wherein the ring body (22a, 22b) is configured to expand in the radial direction as a result of the top body (21a, 21b) being displaced from the extended position towards the compressed position, the method comprising the steps of:- providing the cellulose blank (11) into the moulding tool between the first mould part (16) and the second mould part (17),- displacing at least one of the first mould part (16) and the second mould part (17) in the axial direction in relation to each other and towards each other,- expanding the ring body (22a, 22b) in the radial direction by displacing the top body (21a, 21b) from the extended position towards the compressed position, and- abutting the top body (21a, 21b) and the base body (20a, 20b) of said at least one mould part in the axial direction when the top body (21a, 21b) reaches the compressed position, whereby the ring body (22a, 22b) has radially expanded shape.

15. A rigid cellulose product (2) having essentially non-flat general shape, manufactured by the method according to claim 14, wherein the rigid cellulose product (2) has a bottom portion (24) and a wall (28) connected to and extending in the axial direction from the bottom portion (24), wherein the wall (28) comprises a circumferential undercut groove (23).

16. The rigid cellulose product (2) according to claim 15, wherein the rigid cellulose product (2) comprises cellulose fibres from a cellulose raw material (8) constituted by virgin cellulose fibres and / or recycled cellulose fibres, wherein the cellulose fibres originate from wood pulps such as kraft pulp, sulphite pulp, mechanical pulp, thermomechanical pulp, chemical treated mechanical pulp, chemi-thermomechanical pulp, and / or from non-wood pulps such as bagasse, bamboo, abaca, hemp, flax, cotton.

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