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WO2025068140A1 - Apparatus and method for dry manufacturing rigid cellulose products - Google Patents

Apparatus and method for dry manufacturing rigid cellulose products Download PDF

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Publication number
WO2025068140A1
WO2025068140A1 PCT/EP2024/076715 EP2024076715W WO2025068140A1 WO 2025068140 A1 WO2025068140 A1 WO 2025068140A1 EP 2024076715 W EP2024076715 W EP 2024076715W WO 2025068140 A1 WO2025068140 A1 WO 2025068140A1
Authority
WO
WIPO (PCT)
Prior art keywords
male
mould part
cellulose
shaping
cellulose blank
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
PCT/EP2024/076715
Other languages
French (fr)
Inventor
Adam Johansson
Marcus CORIN
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Yangi AB
Original Assignee
Yangi AB
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Yangi AB filed Critical Yangi AB
Publication of WO2025068140A1 publication Critical patent/WO2025068140A1/en
Pending legal-status Critical Current
Anticipated expiration legal-status Critical

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B31—MAKING ARTICLES OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER; WORKING PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
    • B31D—MAKING ARTICLES OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER, NOT PROVIDED FOR IN SUBCLASSES B31B OR B31C
    • B31D5/00—Multiple-step processes for making three-dimensional articles ; Making three-dimensional articles
    • B31D5/02—Multiple-step processes for making three-dimensional articles ; Making three-dimensional articles including pressing
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B31—MAKING ARTICLES OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER; WORKING PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
    • B31B—MAKING CONTAINERS OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
    • B31B50/00—Making rigid or semi-rigid containers, e.g. boxes or cartons
    • B31B50/02—Feeding or positioning sheets, blanks or webs
    • B31B50/022—Holders for feeding or positioning blanks or webs
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B31—MAKING ARTICLES OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER; WORKING PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
    • B31B—MAKING CONTAINERS OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
    • B31B50/00—Making rigid or semi-rigid containers, e.g. boxes or cartons
    • B31B50/02—Feeding or positioning sheets, blanks or webs
    • B31B50/04—Feeding sheets or blanks
    • B31B50/07—Feeding sheets or blanks by air pressure or suction
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B31—MAKING ARTICLES OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER; WORKING PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
    • B31F—MECHANICAL WORKING OR DEFORMATION OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
    • B31F1/00—Mechanical deformation without removing material, e.g. in combination with laminating
    • B31F1/0077—Shaping by methods analogous to moulding, e.g. deep drawing techniques
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
    • B65D1/00—Rigid or semi-rigid containers having bodies formed in one piece, e.g. by casting metallic material, by moulding plastics, by blowing vitreous material, by throwing ceramic material, by moulding pulped fibrous material or by deep-drawing operations performed on sheet material
    • B65D1/34—Trays or like shallow containers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B31—MAKING ARTICLES OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER; WORKING PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
    • B31B—MAKING CONTAINERS OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
    • B31B50/00—Making rigid or semi-rigid containers, e.g. boxes or cartons
    • B31B50/59—Shaping sheet material under pressure
    • B31B50/592—Shaping sheet material under pressure using punches or dies
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B31—MAKING ARTICLES OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER; WORKING PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
    • B31B—MAKING CONTAINERS OF PAPER, CARDBOARD OR MATERIAL WORKED IN A MANNER ANALOGOUS TO PAPER
    • B31B50/00—Making rigid or semi-rigid containers, e.g. boxes or cartons
    • B31B50/59—Shaping sheet material under pressure
    • B31B50/594—Modifying the shape of tubular boxes or of paper bottle necks
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
    • B65D21/00—Nestable, stackable or joinable containers; Containers of variable capacity
    • B65D21/02—Containers specially shaped, or provided with fittings or attachments, to facilitate nesting, stacking, or joining together
    • B65D21/0233—Nestable containers

Definitions

  • the present invention relates in general to the field of apparatus and method 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 apparatus and method are defined to provide rigid cellulose products having a considerable depth.
  • the apparatus comprises a moulding tool having a male mould part and a female mould part having co-operating designs, wherein at least one of the male mould part and the female mould part is displaceable in an axial direction in relation to the other in order to press the cellulose blank therebetween into final shape by applying a predetermined pressure P in the axial direction of the moulding tool, wherein the female mould part comprises a main recess having a bottom surface, a wall surface extending essentially in the axial direction, and a transitional edge surface located between the bottom surface and the wall surface.
  • 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.
  • One advantage of using wet-forming techniques is that the moulding tool is filled with a wet cellulose slurry and thereafter the cellulose slurry is dried and obtains the shape of the moulding tool without any risk of cracking of the moulded cellulose product at the transitional edge portion between the bottom and the wall.
  • 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. a thermos-forming press.
  • One known way to try to solve the problem of cracked cellulose products is to provide a coating or the like to the projection of the male mould part and to the recess of the female mould part in order to decrease the friction between the cellulose blank and the moulding tool in order to counteract material draw and elongation.
  • Such measures may have some positive effect during moulding/pressing of shallow cellulose products having uncomplicated design.
  • the inventors of the present invention have concluded by thorough research that such measures do not have any beneficial effect on the problem concerning material draw and elongation during moulding/pressing rigid cellulose products having non-flat general shape and a considerable depth, on the contrary it has negative effect resulting in more cracks in the transitional edge portion of the cellulose product.
  • Another way to try to solve the problem of cracked cellulose products is to use a large release angle of the walls, like 45 degrees.
  • the present invention aims at obviating the aforementioned and other disadvantages and failings of previously known apparatus for dry manufacturing rigid cellulose products, and at providing an improved apparatus and method for dry manufacturing rigid cellulose products having non-flat general shape and a considerable depth.
  • a primary object of the present invention is to provide an improved apparatus and method for dry forming/manufacturing rigid cellulose products having non-flat general shape and a considerable depth, 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 apparatus and method for dry forming/manufacturing rigid cellulose products having non-flat general shape and a considerable depth, wherein the moulded/pressed rigid cellulose product is free from cracks at the transitional edge regions between the bottom and the wall. It is another object of the present invention to provide an improved apparatus and method for dry forming/manufacturing rigid cellulose products having non-flat general shape and a considerable depth, wherein the final cellulose product has great dimensional accuracy.
  • an apparatus of the initially defined type wherein the apparatus further comprises a male pre-shaping part configured for pre-shaping the cellulose blank in the main recess of the female mould part before the pressing of the cellulose blank into final shape, by insertion of the male pre-shaping part into the main recess of the female mould part having the cellulose blank located therebetween, wherein the male pre-shaping part comprises a bottom surface, a wall surface extending essentially in the axial direction, and a transitional edge surface located between the bottom surface and the wall surface, and wherein the male pre-shaping part, in connection with at least one of the bottom surface and the transitional edge surface thereof, comprises holding means configured for fixating the cellulose blank in relation to the bottom surface of the male pre-shaping part during the insertion of the male pre-shaping part into the main recess of the female mould part.
  • a method for dry manufacturing rigid cellulose products having essentially non-flat general shape from a cellulose blank wherein the apparatus comprises a moulding tool having a male mould part and a female mould part having co-operating designs, wherein at least one of the male mould part and the female mould part is displaceable in an axial direction in relation to the other in order to press the cellulose blank therebetween into final shape by applying a predetermined pressure P in the axial direction of the moulding tool, wherein the female mould part comprises a main recess having a bottom surface, a wall surface extending essentially in the axial direction, and a transitional edge surface located between the bottom surface and the wall surface.
  • the method comprises the steps of:
  • a male pre-shaping part that comprises a bottom surface, a wall surface extending essentially in the axial direction, and a transitional edge surface located between the bottom surface and the wall surface, wherein at least one of the bottom surface and the transitional surface of the male pre-shaping part comprises holding means
  • the present invention is based on the insight that it is advantageous that the cellulose blank is given the same or corresponding overall shape as the final shape of the cellulose product before a pressing force is applied to the cellulose blank, in order to avoid cracks at the bottom region and the transitional edge region of the cellulose product.
  • the pre-shaping of the cellulose blank to fit the main recess of the female mould part before pressing entails that any apparent material draw and elongation before the pressing step is prevented, and entails that the relative displacement between the respective mould part and the cellulose blank in a direction perpendicular to the thickness of the cellulose blank during the pressing step is prevented/minimized, i.e. extensive material draw and elongation during the pressing step is also prevented.
  • the risk for creating/generating cracks at the bottom region or at the transitional edge region of the cellulose product during the pressing step of the cellulose blank is eliminated, leading to crack free moulding/pressing of the cellulose product.
  • the inventors have discovered that the previously used measure to lower the friction at both the male mould part and the female mould part by means of a coating will actually increase the effect of the projection of the male mould part piercing through the cellulose blank and/or creating cracks at the transitional edge region between the bottom and the wall.
  • the holding means of the male pre-shaping part comprises a plurality of apertures arranged in the at least one of the bottom surface and the transitional surface of the male pre-shaping part, and comprises a low- pressure chamber arranged in fluid communication with said plurality of apertures.
  • under-pressure is used to attract and fixate the bottom region of the cellulose blank to the bottom surface of the male pre-shaping part during the pre-shaping step.
  • the distance between the bottom surface of the male pre-shaping part and the bottom surface of the female mould part during pre-shaping of the cellulose blank in the main recess of the female mould part is equal to or more than seven times the distance between the bottom surface of the male mould part and the bottom surface of the female mould part during pressing of the cellulose blank into final shape.
  • the distance between the wall surface of the male pre-shaping part and the wall surface of the female mould part during pre-shaping of the cellulose in the main recess of the female mould part is equal to or more than seven times the distance between the wall of the male mould part and the wall surface of the female mould part during pressing of the cellulose blank into final shape.
  • the male pre-shaping part is part of a transfer means configured to provide the cellulose blank into the moulding tool. Thereby the cycle time in the moulding tool can be decreased.
  • Fig. 1 is a schematic illustration of a production line or apparatus for dry manufacturing rigid cellulose products
  • Fig. 2 is a schematic illustration of an inventive moulding tool comprising a male mould part and a female mould part, wherein a male pre-shaping part is provided into the moulding tool and wherein a cellulose blank is provided into the moulding tool
  • Fig. 3 is a schematic illustration of the moulding tool during pre-shaping of the cellulose blank in the main recess of the female mould part
  • Fig. 4 is a schematic illustration of the moulding tool during forming/pressing of the cellulose product
  • Fig. 5 is a schematic illustration of the moulding tool after the forming/pressing step and the cellulose product is released from the moulding tool
  • Fig. 6 is a schematic illustration of a cellulose product wherein the scrap area is removed from the cellulose product
  • Fig. 7 is a schematic illustration of an inventive moulding tool comprising a male mould part and a female mould part, wherein the male pre-shaping part is part of a transfer means and wherein a cellulose blank is provided into the moulding tool by means of the preshaping part.
  • 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.
  • 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.
  • 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.
  • 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/apparatus 1 may be arranged and set-up according to different well-known ways.
  • Figure 6 disclose a rigid cellulose product 2 constituted by a container/tray, wherein the tray is formed using the inventive method.
  • the tray 2 comprises a container wall 3 and an opening 4 defined by a circumferential rim/brim 5 located at the upper/free end of the container wall 3.
  • the brim 5 has an angled shape having an essentially radially extending upper surface and a turned-down outer edge, however it shall be pointed out that the cross-section of the brim 5 may have other shapes.
  • the tray 2 may have truncated cone shape having straight wall 3, narrowing in the direction away from the opening 4, in accordance with figure 7 embodiment, or may for instance have curved-shaped wall 3 seen in the axial plane.
  • the cross section of the wall 3 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 tray 2.
  • the tray 2 may comprise a flat bottom 6, or the bottom may comprise local ribs, projections, etc. for strength and rigidity of the cellulose product 2.
  • the bottom 6 may be located at the very lower end of the wall 3, according to figure 7 embodiment, or be located at a distance from the lower end of the wall 3, or a combination thereof.
  • the walls of the moulding tool are inclined in order to obtain a release angle for the cellulose product 2, and in order to obtain adequate press force to the wall region of the cellulose product 2.
  • Cellulose raw material 7 is provided to the production line, and is fed to a separating/ disintegrating unit 8 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 9.
  • the cellulose fibres are laid by the dispenser on a moving or stationary perforated surface of the cellulose blank forming unit 9.
  • the cellulose fibre carrying air flow may be generated by suitable device located upstream and/or downstream the perforated surface.
  • the generated cellulose blank generally designated 10 is transported/ transferred to a product forming unit 11, whereby rigid cellulose products 2 are formed and discharged from the product forming unit 11.
  • the cellulose blank forming unit 9 may be configured to generate a continuous cellulose blank 10 and/or discontinuous/discrete cellulose blanks 10. Preferably discontinuous/discrete cellulose blanks 10 are fed into the product forming unit 11.
  • the cellulose raw material 7 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 7 is in the form of sheets and/or reeled pulp or paper, it can be fed directly into the separating unit 8. However, in case said cellulose raw material 7 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 8 may be necessary to be used for separating and dosing said cellulose raw material 7 from said bale or sheets in smaller quantities. The shredder(s) prepare cellulose raw material 7 to be accepted by said separating unit 8.
  • the separating unit 8 disintegrates the cellulose raw material 7 into separated cellulose fibres.
  • Said one or plurality of shredder(s) are arranged before said one or a plurality of separating unit(s) 8, so that an output of one of said shredder is connected to an input of one of said separating units 8.
  • the shredders may be arranged in parallel to each other or in series with each other, and the disintegrating units 8 may be arranged in parallel to each other or in series with each other.
  • the shredders and the disintegrating units 8 together constitute a cellulose fibre separating unit, arranged upstream the cellulose blank forming unit 9.
  • Said cellulose raw material 7 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.
  • the separating unit 8 may according to various embodiments be constituted by a hammer mill. In said separating unit 8 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 8 and/or by choosing a different separating unit 8 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.
  • 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 12, located downstream the cellulose blank forming unit 9 and upstream the product forming unit 11.
  • a pre-compression and/or imprinting unit 12 located downstream the cellulose blank forming unit 9 and upstream the product forming unit 11.
  • an air-laid fluffy cellulose blank 10 having a first thickness may be compressed into a cellulose blank 10 having a second thickness, wherein said second thickness is thinner than said first thickness, and/or may be provided with an imprinting pattern.
  • 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.
  • the product forming unit 11 comprises a press unit 13, and may optionally comprise a preheating unit 14 arranged upstream the press unit 13.
  • said cellulose blank 10 may be heated to an elevated temperature before being fed into the press unit 13 of the product forming unit 11.
  • said press unit 13 may or may not comprise heating.
  • said press unit 13 may be a heated press unit 13 for heating said cellulose blank 10 during pressing.
  • preheating of said cellulose blank 10 using a pre-heating unit 14 is optional.
  • preheating of the cellulose blank 10 in said pre-heating unit 14 may be combined with a heated press unit 13.
  • Having a pre-heating unit 14 in combination with a heated press unit 13 will speed up the manufacturing process in the product forming unit 11, and improve the quality/rigidity of the final rigid cellulose product 2.
  • the cellulose blank 10 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.
  • the press unit 13 comprises a moulding tool having a first mould part 15 and a second mould part 16 having co-operating designs, wherein at least one of the first mould part 15 and the second mould part 16 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 10 loaded therebetween.
  • the mutual displacement direction between the first mould part 15 and the second mould part 16 is disclosed as being vertical, however the mutual displacement may be horizontal or any other suitable angle.
  • the cellulose blank 10 loaded into the moulding tool is preferably constituted by an air-laid cellulose blank.
  • the cellulose blank 10 may be generated upstream the product forming unit 11 in the same apparatus/production line and provided/transferred to the product forming unit 11, or may be generated at a separate location and provided/transferred to the product forming unit 11 via intermediate handling and storage.
  • the cellulose blank 10 may be provided/loaded into the moulding tool by any feasible means.
  • the second mould part 16 of the moulding tool is a female mould part, i.e. having a main recess 17 for receiving the cellulose blank 10
  • the first mould part 15 of the moulding tool is a male mould part, i.e. having a main projection 18 for cooperation with said main recess 17 of the female mould part by being inserted therein, such that during the pressing/forming step the cellulose blank 10 is pressed into a final rigid non-flat shape, which may be any conceivable non-flat design/shape.
  • the main projection 18 of the male mould part 15 has a bottom surface 19, a wall surface 20 extending essentially in the axial direction, and a transitional edge surface 21 located between the bottom surface 20 and the wall surface 21.
  • the main recess 17 of the female mould part 16 has a bottom surface 22, a wall surface 23 extending essentially in the axial direction, and a transitional edge surface 24 located between the bottom surface 22 and the wall surface 23.
  • the cellulose blank 10 is pressed between the surfaces of the male mould part 15 and the surfaces of the female mould part 16 into final shape by applying a predetermined pressure P in the axial direction of the moulding tool. See figure 4.
  • the cellulose blank 10 Radially outside the final rigid cellulose product 2, the cellulose blank 10 comprises a scrap area 25 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. See figure 6.
  • the predetermined pressure P is in the range 40-10000N/cm 2 , preferably in the range 100- 4000N/cm 2 . According to various embodiments said predetermined pressures are above 1000 N/ cm 2 , and according to various embodiments said predetermined pressures are below 2500 N/ cm 2 .
  • 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.
  • the cellulose blank 10 is provided into the moulding tool by a non-disclosed transfer means, for instance by being injected from and by means of a conveyer belt, being introduced using a paddle-shaped equipment, being introduced by hand, etc.
  • the apparatus 1 further comprises a male pre-shaping part, generally designated 26, configured for pre-shaping the cellulose blank 10 in the main recess 17 of the female mould part 16 before the pressing of the cellulose blank 10 into final shape.
  • the male pre-shaping part 26 is introduced into the moulding tool, for instance by means of an automated/mechanical arm.
  • the male pre-shaping part 26 is different from the male mould part 15.
  • the male pre-shaping part 26 comprises a bottom surface 27, a wall surface 28 extending essentially in the axial direction, and a transitional edge surface 29 located between the bottom surface 27 and the wall surface 28.
  • the pre-shaping of the cellulose blank 10 is realized by insertion of the male preshaping part 26 into the main recess 17 of the female mould part 16 having the cellulose blank 10 located therebetween.
  • the cellulose blank 10 is preferably pushed against the surfaces of the main recess 17 of the female mould part 16, without providing any extensive pressure.
  • the side of the cellulose blank 10 facing the main recess 17 of the female mould part 16 shall preferably abut the surfaces of the main recess 17 after the preshaping step.
  • the cellulose blank 10 is subject to plastic deformation due to the weak connection between the separate cellulose fibres in the cellulose blank 10, but the essentially uniform thickness of the cellulose blank 10 is maintained since the cellulose blank 10 is wrapped about the male pre-shaping part 26 without entailing any extensive material draw and elongation.
  • the male pre-shaping part 26 is retracted, the pre-shaped cellulose blank 10 will stay in the pre-shaped shape/position in the main recess 17 of the female mould part 16.
  • the general shape of the male pre-shaping part 26 is preferably corresponding to the general shape of the male mould part 15, but in a scaled-down version such that the cellulose blank 10 is not pressed between the male pre-shaping part 26 and the female mould part 16 during the pre-shaping step. It is vital that the shape of the pre-shaped cellulose blank 10 is configured to receive the main projection 18 of the male mould part 15 without involving deformation/creasing of the wall regions of the pre-shaped cellulose blank 10. Thus, the shape/dimensions of the male pre-shaping part 26 cannot be too small in relation to the shape/dimensions of the male mould part 15. Seen in the radial plane the boundary of the transitional edge surface 21 of the male mould part 15 has to be smaller than the boundary of the upper part of the wall surface 28 of the male pre-shaping part 26.
  • the distance between the bottom surface 27 of the male pre-shaping part 26 and the bottom surface 22 of the female mould part 16 during preshaping of the cellulose blank 10 in the main recess 17 of the female mould part 16 is equal to or more than seven times the distance between the bottom surface 19 of the male mould part 15 and the bottom surface 22 of the female mould part 16 during pressing of the cellulose blank 10 into final shape.
  • the minimum distance between the bottom surface 27 of the male preshaping part 26 and the bottom surface 22 of the female mould part 16 during the pre-shaping process step is always equal to or more than seven times the minimum distance between the bottom surface 19 of the male mould part 15 and the bottom surface 22 of the female mould part 16 during the pressing process step, i.e.
  • said distance between the bottom surface 27 of the male pre-shaping part 26 and the bottom surface 22 of the female mould part 16 during pre-shaping of the cellulose blank 10 is equal to or less than fifteen times the distance between the bottom surface 19 of the male mould part 15 and the bottom surface 22 of the female mould part 16 during pressing of the cellulose blank 10 into final shape.
  • the range is 10-13 times the distance between the bottom surface 19 of the male mould part 15 and the bottom surface 22 of the female mould part 16 during pressing of the cellulose blank 10.
  • the thickness of the bottom of the final cellulose product 2 is usually in the range 0,6-0, 8 millimetres. Thereby the cellulose blank is not, or only insignificantly, compressed during the pre-shaping.
  • the distance between the wall surface 28 of the male pre-shaping part 26 and the wall surface 23 of the female mould part 16 during pre-shaping of the cellulose blank 10 is equal to or more than seven times the distance between the wall surface 20 of the male mould part 15 and the wall surface 23 of the female mould part 16 during pressing of the cellulose blank 10 into final shape.
  • the minimum distance between the wall surface 28 of the male pre-shaping part 26 and the wall surface 23 of the female mould part 16 during the pre-shaping process step is always equal to or more than seven times the minimum distance between the wall surface 20 of the male mould part 15 and the wall surface 23 of the female mould part 16 during the pressing process step, i.e. when the male mould part 15 is at its bottom dead centre.
  • said distance between the wall surface 28 of the male pre-shaping part 26 and the wall surface 23 of the female mould part 16 during pre-shaping of the cellulose blank 10 is equal to or less than fifteen times the distance between the wall surface 20 of the male mould part 15 and the wall surface 23 of the female mould part 16 during pressing of the cellulose blank 10 into final shape.
  • the range is 10-13 times the distance between the wall surface 20 of the male mould part 15 and the wall surface 23 of the female mould part 16 during pressing of the cellulose blank 10.
  • the thickness of the wall of the final cellulose product 2 is usually in the range 0,6-0, 8 millimetres. Thereby the cellulose blank is not, or only insignificantly, compressed during the pre-shaping.
  • the male pre-shaping part 26 in connection with at least one of the bottom surface 27 and the transitional edge surface 29 thereof, comprises holding means, generally designated 30, configured for fixating the cellulose blank 10 in relation to the bottom surface 27 of the male pre-shaping part 26 during the insertion of the male pre-shaping part 26 into the main recess 17 of the female mould part 16. Thereby the cellulose blank 10 is prevented from material draw and elongation at the bottom region of the cellulose blank 10.
  • the holding means 30 of the male pre-shaping part 26 comprises a plurality of apertures 31 arranged in the at least one of the bottom surface 27 and the transitional surface 29 of the male pre-shaping part 26, and comprises a low-pressure chamber 32 arranged in fluid communication with said plurality of apertures 31.
  • the low-pressure chamber 32 is preferably in fluid communication with at fan or the like equipment configured to generate under-pressure by removing air/gas from the low-pressure chamber 32.
  • the diameter of the respective aperture 31 is equal to or more than 0,5 mm and equal to or less than 4 mm, preferably equal to or more than 1 mm and equal to or less than 3 mm, preferably about 2 millimetre.
  • the apertures 31 of the holding means 30 are in the disclosed embodiment arranged at the bottom surface 27 of the male pre-shaping part 26.
  • the holding means 30 of the male preshaping part 26 comprises a coarse surface area having a plurality of protrusions/pins configured to temporary engage the cellulose blank 10, at least one of the bottom surface 27 and the transitional surface 29 of the male pre-shaping part 26 comprising said coarse surface area.
  • the male pre-shaping part 26 is removed from the moulding tool and the cellulose blank 10 is pressed between the male mould part 15 and the female mould part 16 into final shape by applying the predetermined pressure P in the axial direction of the moulding tool according to figure 4.
  • the main projection 18 of the male mould part 15 is inserted into the pre-shaped cellulose blank 10 and at the same time into the main recess 17 of the female mould part 16, wherein the wall 3 and bottom 6 of the cellulose product 2 are pressed.
  • the male mould part 15 and the female mould part 16 are disengaged, i.e. displaced in the axial direction away from each other, whereby the rigid cellulose product 2 may be removed/ejected from the moulding tool.
  • the male preshaping part 26 is part of a transfer means configured to provide the cellulose blank 10 into the moulding tool.
  • the male pre-shaping part 26 engage/lifts the cellulose blank 10 outside the moulding tool and provides/transfer the cellulose blank 10 into the moulding tool, as a first substep. Thereafter the pre-shaping of the cellulose blank 10 takes place in the same way as described hereinabove, as a second sub-step.
  • apertures 31 of the holding means 30 are arranged at the transitional edge surface 29 of the male pre-shaping part 26, alone or in addition to holding means 30 at the bottom surface 27 of the male pre-shaping part 26, in order to prevent the outer parts of the cellulose blank 10 to drop down and risk getting stuck somewhere during the transfer of the cellulose blank 10 into the moulding tool by means of the male pre-shaping part 26.

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Abstract

The present invention relates to an apparatus and method for dry manufacturing rigid cellulose products (2) having essentially non-flat general shape from a cellulose blank (10), the apparatus (1) comprising a moulding tool having a male mould part (15) and a female mould part (16) having co-operating designs, wherein at least one of the male mould part (15) and the female mould part (16) is displaceable in an axial direction in relation to the other in order to press the cellulose blank (10) therebetween into final shape by applying a predetermined pressure P in the axial direction of the moulding tool, wherein the female mould part (16) comprises a main recess (17) having a bottom surface (22), a wall surface (23) extending essentially in the axial direction, and a transitional edge surface (24) located between the bottom surface (22) and the wall surface (23). The apparatus (1) further comprises a male pre-shaping part (26) configured for pre-shaping the cellulose blank (10) in the main recess (17) of the female mould part (16) before the pressing of the cellulose blank (10) into final shape, by insertion of the male pre-shaping part (26) into the main recess (17) of the female mould part (16) having the cellulose blank (10) located therebetween, wherein the male pre-shaping part (26) comprises a bottom surface (27), a wall surface (28) extending essentially in the axial direction, and a transitional edge surface (29) located between the bottom surface (27) and the wall surface (28), and wherein the male pre-shaping part (26), in connection with at least one of the bottom surface (27) and the transitional edge surface (29) thereof, comprises holding means (30) configured for fixating the cellulose blank (10) in relation to the bottom surface (27) of the male pre-shaping part (26) during the insertion of the male pre-shaping part (26) into the main recess (17) of the female mould part (16).

Description

APPARATUS AND METHOD FOR DRY MANUFACTURING RIGID CELLULOSE PRODUCTS
Technical field of the Invention
The present invention relates in general to the field of apparatus and method 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 apparatus and method are defined to provide rigid cellulose products having a considerable depth.
The apparatus comprises a moulding tool having a male mould part and a female mould part having co-operating designs, wherein at least one of the male mould part and the female mould part is displaceable in an axial direction in relation to the other in order to press the cellulose blank therebetween into final shape by applying a predetermined pressure P in the axial direction of the moulding tool, wherein the female mould part comprises a main recess having a bottom surface, a wall surface extending essentially in the axial direction, and a transitional edge surface located between the bottom surface and the wall surface.
Background of the Invention
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.
One advantage of using wet-forming techniques is that the moulding tool is filled with a wet cellulose slurry and thereafter the cellulose slurry is dried and obtains the shape of the moulding tool without any risk of cracking of the moulded cellulose product at the transitional edge portion between the bottom and the wall.
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.
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. a thermos-forming press.
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 male mould part and a female mould part configured to cooperate with each other, is well known. However, the technical field of dry manufacturing rigid cellulose products having non-flat general shape and great depth, such as trays, deep plates, cups, or the like, is still exposed to challenges.
During moulding/pressing of the rigid cellulose product having non-flat general shape from the more or less flat cellulose blank, material draw and elongation in the cellulose blank will take place during the insertion of the main projection of the male mould part into the main recess of the female mould part, and during the pressing of the cellulose product. Especially for deep cellulose products, cracks will arise at the transitional edge regions between the bottom and the wall and at the bottom and thereby the possible product shapes that can be manufactured is limited. Thereto, uneven thickness of the final cellulose product is a problem.
One known way to try to solve the problem of cracked cellulose products, is to provide a coating or the like to the projection of the male mould part and to the recess of the female mould part in order to decrease the friction between the cellulose blank and the moulding tool in order to counteract material draw and elongation. Such measures may have some positive effect during moulding/pressing of shallow cellulose products having uncomplicated design. However, the inventors of the present invention have concluded by thorough research that such measures do not have any beneficial effect on the problem concerning material draw and elongation during moulding/pressing rigid cellulose products having non-flat general shape and a considerable depth, on the contrary it has negative effect resulting in more cracks in the transitional edge portion of the cellulose product. Another way to try to solve the problem of cracked cellulose products is to use a large release angle of the walls, like 45 degrees.
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 a considerable depth. of the Invention
The present invention aims at obviating the aforementioned and other disadvantages and failings of previously known apparatus for dry manufacturing rigid cellulose products, and at providing an improved apparatus and method for dry manufacturing rigid cellulose products having non-flat general shape and a considerable depth.
A primary object of the present invention is to provide an improved apparatus and method for dry forming/manufacturing rigid cellulose products having non-flat general shape and a considerable depth, 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 apparatus and method for dry forming/manufacturing rigid cellulose products having non-flat general shape and a considerable depth, wherein the moulded/pressed rigid cellulose product is free from cracks at the transitional edge regions between the bottom and the wall. It is another object of the present invention to provide an improved apparatus and method for dry forming/manufacturing rigid cellulose products having non-flat general shape and a considerable depth, wherein the final cellulose product has great dimensional accuracy. of the Invention
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.
According to a first aspect of the present invention, there is provided an apparatus of the initially defined type wherein the apparatus further comprises a male pre-shaping part configured for pre-shaping the cellulose blank in the main recess of the female mould part before the pressing of the cellulose blank into final shape, by insertion of the male pre-shaping part into the main recess of the female mould part having the cellulose blank located therebetween, wherein the male pre-shaping part comprises a bottom surface, a wall surface extending essentially in the axial direction, and a transitional edge surface located between the bottom surface and the wall surface, and wherein the male pre-shaping part, in connection with at least one of the bottom surface and the transitional edge surface thereof, comprises holding means configured for fixating the cellulose blank in relation to the bottom surface of the male pre-shaping part during the insertion of the male pre-shaping part into the main recess of the female mould part.
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, wherein the apparatus comprises a moulding tool having a male mould part and a female mould part having co-operating designs, wherein at least one of the male mould part and the female mould part is displaceable in an axial direction in relation to the other in order to press the cellulose blank therebetween into final shape by applying a predetermined pressure P in the axial direction of the moulding tool, wherein the female mould part comprises a main recess having a bottom surface, a wall surface extending essentially in the axial direction, and a transitional edge surface located between the bottom surface and the wall surface. The method comprises the steps of:
- providing the cellulose blank into the moulding tool,
- providing a male pre-shaping part that comprises a bottom surface, a wall surface extending essentially in the axial direction, and a transitional edge surface located between the bottom surface and the wall surface, wherein at least one of the bottom surface and the transitional surface of the male pre-shaping part comprises holding means,
- pre-shaping the cellulose blank in the main recess of the female mould part by inserting the male pre-shaping part into the main recess of the female mould part having the cellulose blank located therebetween,
- fixating the cellulose blank in relation to the bottom surface of the male pre-shaping part during the insertion of the male pre-shaping part into the main recess of the female mould part by means of said holding means, and
- pressing the cellulose blank into final shape.
Thus, the present invention is based on the insight that it is advantageous that the cellulose blank is given the same or corresponding overall shape as the final shape of the cellulose product before a pressing force is applied to the cellulose blank, in order to avoid cracks at the bottom region and the transitional edge region of the cellulose product. By fixating the bottom region of the cellulose blank to the male pre-shaping part during the pre-shaping step, there is no apparent material draw and elongation of the cellulose blank at the bottom region and at the transitional edge region of the cellulose blank. There is only a draping of the wall region of the cellulose blank against the wall surface of the main recess of the female mould part during the pre-shaping step.
Thus, the pre-shaping of the cellulose blank to fit the main recess of the female mould part before pressing entails that any apparent material draw and elongation before the pressing step is prevented, and entails that the relative displacement between the respective mould part and the cellulose blank in a direction perpendicular to the thickness of the cellulose blank during the pressing step is prevented/minimized, i.e. extensive material draw and elongation during the pressing step is also prevented. Thus, the risk for creating/generating cracks at the bottom region or at the transitional edge region of the cellulose product during the pressing step of the cellulose blank is eliminated, leading to crack free moulding/pressing of the cellulose product.
The inventors have discovered that the previously used measure to lower the friction at both the male mould part and the female mould part by means of a coating will actually increase the effect of the projection of the male mould part piercing through the cellulose blank and/or creating cracks at the transitional edge region between the bottom and the wall.
According to various example embodiments of the present invention the holding means of the male pre-shaping part comprises a plurality of apertures arranged in the at least one of the bottom surface and the transitional surface of the male pre-shaping part, and comprises a low- pressure chamber arranged in fluid communication with said plurality of apertures. Thereby under-pressure is used to attract and fixate the bottom region of the cellulose blank to the bottom surface of the male pre-shaping part during the pre-shaping step.
According to various example embodiments of the present invention the distance between the bottom surface of the male pre-shaping part and the bottom surface of the female mould part during pre-shaping of the cellulose blank in the main recess of the female mould part is equal to or more than seven times the distance between the bottom surface of the male mould part and the bottom surface of the female mould part during pressing of the cellulose blank into final shape. Thereby it is secured that no extensive pressing force is applied to the cellulose blank during the pre-shaping step, i.e. the cellulose blank is kept loose in order to preserve maximum mouldability of the cellulose blank to the pressing step.
According to various example embodiments of the present invention the distance between the wall surface of the male pre-shaping part and the wall surface of the female mould part during pre-shaping of the cellulose in the main recess of the female mould part is equal to or more than seven times the distance between the wall of the male mould part and the wall surface of the female mould part during pressing of the cellulose blank into final shape. Thereby it is secured that no extensive pressing force is applied to the wall region of the cellulose blank during the pre-shaping step, i.e. there is no extensive frictional force acting against the cellulose blank at the wall region during the insertion of the male pre-shaping part into the main recess of the female mould part and thereby material draw and elongation is prevented during the pre-shaping step.
According to various example embodiments of the present invention the male pre-shaping part is part of a transfer means configured to provide the cellulose blank into the moulding tool. Thereby the cycle time in the moulding tool can be decreased.
Further advantages with and features of the invention will be apparent from the following detailed description of preferred embodiments.
Brief description of the drawings
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:
Fig. 1 is a schematic illustration of a production line or apparatus for dry manufacturing rigid cellulose products,
Fig. 2 is a schematic illustration of an inventive moulding tool comprising a male mould part and a female mould part, wherein a male pre-shaping part is provided into the moulding tool and wherein a cellulose blank is provided into the moulding tool, Fig. 3 is a schematic illustration of the moulding tool during pre-shaping of the cellulose blank in the main recess of the female mould part,
Fig. 4 is a schematic illustration of the moulding tool during forming/pressing of the cellulose product,
Fig. 5 is a schematic illustration of the moulding tool after the forming/pressing step and the cellulose product is released from the moulding tool,
Fig. 6 is a schematic illustration of a cellulose product wherein the scrap area is removed from the cellulose product, and
Fig. 7 is a schematic illustration of an inventive moulding tool comprising a male mould part and a female mould part, wherein the male pre-shaping part is part of a transfer means and wherein a cellulose blank is provided into the moulding tool by means of the preshaping part.
Detailed description of preferred embodiments of the invention
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.
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.
Reference is initially made to figures 1 and 6, 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/apparatus 1 may be arranged and set-up according to different well-known ways.
Figure 6 disclose a rigid cellulose product 2 constituted by a container/tray, wherein the tray is formed using the inventive method. The tray 2 comprises a container wall 3 and an opening 4 defined by a circumferential rim/brim 5 located at the upper/free end of the container wall 3. According to figure 7 embodiment the brim 5 has an angled shape having an essentially radially extending upper surface and a turned-down outer edge, however it shall be pointed out that the cross-section of the brim 5 may have other shapes. The tray 2 may have truncated cone shape having straight wall 3, narrowing in the direction away from the opening 4, in accordance with figure 7 embodiment, or may for instance have curved-shaped wall 3 seen in the axial plane. By having inclined container walls 3 multiple trays 2 are stackable one inside the other when they are empty. The cross section of the wall 3 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 tray 2. The tray 2 may comprise a flat bottom 6, or the bottom may comprise local ribs, projections, etc. for strength and rigidity of the cellulose product 2. The bottom 6 may be located at the very lower end of the wall 3, according to figure 7 embodiment, or be located at a distance from the lower end of the wall 3, or a combination thereof. The walls of the moulding tool are inclined in order to obtain a release angle for the cellulose product 2, and in order to obtain adequate press force to the wall region of the cellulose product 2.
Cellulose raw material 7 is provided to the production line, and is fed to a separating/ disintegrating unit 8 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 9. The cellulose fibres are laid by the dispenser on a moving or stationary perforated surface of the cellulose blank forming unit 9. 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 10, is transported/ transferred to a product forming unit 11, whereby rigid cellulose products 2 are formed and discharged from the product forming unit 11.
The cellulose blank forming unit 9 may be configured to generate a continuous cellulose blank 10 and/or discontinuous/discrete cellulose blanks 10. Preferably discontinuous/discrete cellulose blanks 10 are fed into the product forming unit 11.
The cellulose raw material 7 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 7 is in the form of sheets and/or reeled pulp or paper, it can be fed directly into the separating unit 8. However, in case said cellulose raw material 7 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 8 may be necessary to be used for separating and dosing said cellulose raw material 7 from said bale or sheets in smaller quantities. The shredder(s) prepare cellulose raw material 7 to be accepted by said separating unit 8. The separating unit 8 disintegrates the cellulose raw material 7 into separated cellulose fibres. Said one or plurality of shredder(s) are arranged before said one or a plurality of separating unit(s) 8, so that an output of one of said shredder is connected to an input of one of said separating units 8. The shredders may be arranged in parallel to each other or in series with each other, and the disintegrating units 8 may be arranged in parallel to each other or in series with each other. The shredders and the disintegrating units 8 together constitute a cellulose fibre separating unit, arranged upstream the cellulose blank forming unit 9.
Said cellulose raw material 7 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. The separating unit 8 may according to various embodiments be constituted by a hammer mill. In said separating unit 8 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 8 and/or by choosing a different separating unit 8 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 12, located downstream the cellulose blank forming unit 9 and upstream the product forming unit 11. In the pre-compression and/or imprinting unit 12, an air-laid fluffy cellulose blank 10 having a first thickness may be compressed into a cellulose blank 10 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.
The product forming unit 11 comprises a press unit 13, and may optionally comprise a preheating unit 14 arranged upstream the press unit 13. According to various example embodiments said cellulose blank 10 may be heated to an elevated temperature before being fed into the press unit 13 of the product forming unit 11. In such embodiment(s) where the cellulose blank 10 is preheated before being fed into the press unit 13, said press unit 13 may or may not comprise heating. According to various example embodiment said press unit 13 may be a heated press unit 13 for heating said cellulose blank 10 during pressing. In the case of a heated press unit 13, preheating of said cellulose blank 10 using a pre-heating unit 14 is optional. According to various example embodiments preheating of the cellulose blank 10 in said pre-heating unit 14 may be combined with a heated press unit 13. Having a pre-heating unit 14 in combination with a heated press unit 13 will speed up the manufacturing process in the product forming unit 11, and improve the quality/rigidity of the final rigid cellulose product 2. In the product forming unit 11 the cellulose blank 10 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.
Reference is now made to figure 2, disclosing an example embodiment of the present invention. The press unit 13 comprises a moulding tool having a first mould part 15 and a second mould part 16 having co-operating designs, wherein at least one of the first mould part 15 and the second mould part 16 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 10 loaded therebetween. In the figures the mutual displacement direction between the first mould part 15 and the second mould part 16 is disclosed as being vertical, however the mutual displacement may be horizontal or any other suitable angle. The cellulose blank 10 loaded into the moulding tool, is preferably constituted by an air-laid cellulose blank. The cellulose blank 10 may be generated upstream the product forming unit 11 in the same apparatus/production line and provided/transferred to the product forming unit 11, or may be generated at a separate location and provided/transferred to the product forming unit 11 via intermediate handling and storage. The cellulose blank 10 may be provided/loaded into the moulding tool by any feasible means.
According to various embodiments the second mould part 16 of the moulding tool is a female mould part, i.e. having a main recess 17 for receiving the cellulose blank 10, and the first mould part 15 of the moulding tool is a male mould part, i.e. having a main projection 18 for cooperation with said main recess 17 of the female mould part by being inserted therein, such that during the pressing/forming step the cellulose blank 10 is pressed into a final rigid non-flat shape, which may be any conceivable non-flat design/shape.
The main projection 18 of the male mould part 15 has a bottom surface 19, a wall surface 20 extending essentially in the axial direction, and a transitional edge surface 21 located between the bottom surface 20 and the wall surface 21. The main recess 17 of the female mould part 16 has a bottom surface 22, a wall surface 23 extending essentially in the axial direction, and a transitional edge surface 24 located between the bottom surface 22 and the wall surface 23. The cellulose blank 10 is pressed between the surfaces of the male mould part 15 and the surfaces of the female mould part 16 into final shape by applying a predetermined pressure P in the axial direction of the moulding tool. See figure 4.
Radially outside the final rigid cellulose product 2, the cellulose blank 10 comprises a scrap area 25 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. See figure 6.
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.
According to the example embodiment disclosed in figure 2, the cellulose blank 10 is provided into the moulding tool by a non-disclosed transfer means, for instance by being injected from and by means of a conveyer belt, being introduced using a paddle-shaped equipment, being introduced by hand, etc.
According to the invention the apparatus 1 further comprises a male pre-shaping part, generally designated 26, configured for pre-shaping the cellulose blank 10 in the main recess 17 of the female mould part 16 before the pressing of the cellulose blank 10 into final shape. The male pre-shaping part 26 is introduced into the moulding tool, for instance by means of an automated/mechanical arm. The male pre-shaping part 26 is different from the male mould part 15.
The male pre-shaping part 26 comprises a bottom surface 27, a wall surface 28 extending essentially in the axial direction, and a transitional edge surface 29 located between the bottom surface 27 and the wall surface 28.
Reference is now also made to figure 3 disclosing an example embodiment of the preshaping step. The pre-shaping of the cellulose blank 10 is realized by insertion of the male preshaping part 26 into the main recess 17 of the female mould part 16 having the cellulose blank 10 located therebetween. During the pre-shaping step, the cellulose blank 10 is preferably pushed against the surfaces of the main recess 17 of the female mould part 16, without providing any extensive pressure. Thus, the side of the cellulose blank 10 facing the main recess 17 of the female mould part 16 shall preferably abut the surfaces of the main recess 17 after the preshaping step. During the pre-shaping step, the cellulose blank 10 is subject to plastic deformation due to the weak connection between the separate cellulose fibres in the cellulose blank 10, but the essentially uniform thickness of the cellulose blank 10 is maintained since the cellulose blank 10 is wrapped about the male pre-shaping part 26 without entailing any extensive material draw and elongation. Thus, when the male pre-shaping part 26 is retracted, the pre-shaped cellulose blank 10 will stay in the pre-shaped shape/position in the main recess 17 of the female mould part 16.
The general shape of the male pre-shaping part 26 is preferably corresponding to the general shape of the male mould part 15, but in a scaled-down version such that the cellulose blank 10 is not pressed between the male pre-shaping part 26 and the female mould part 16 during the pre-shaping step. It is vital that the shape of the pre-shaped cellulose blank 10 is configured to receive the main projection 18 of the male mould part 15 without involving deformation/creasing of the wall regions of the pre-shaped cellulose blank 10. Thus, the shape/dimensions of the male pre-shaping part 26 cannot be too small in relation to the shape/dimensions of the male mould part 15. Seen in the radial plane the boundary of the transitional edge surface 21 of the male mould part 15 has to be smaller than the boundary of the upper part of the wall surface 28 of the male pre-shaping part 26.
According to various embodiments, the distance between the bottom surface 27 of the male pre-shaping part 26 and the bottom surface 22 of the female mould part 16 during preshaping of the cellulose blank 10 in the main recess 17 of the female mould part 16 is equal to or more than seven times the distance between the bottom surface 19 of the male mould part 15 and the bottom surface 22 of the female mould part 16 during pressing of the cellulose blank 10 into final shape. Thus, the minimum distance between the bottom surface 27 of the male preshaping part 26 and the bottom surface 22 of the female mould part 16 during the pre-shaping process step is always equal to or more than seven times the minimum distance between the bottom surface 19 of the male mould part 15 and the bottom surface 22 of the female mould part 16 during the pressing process step, i.e. when the male mould part 15 is at its bottom dead centre. Thereto, said distance between the bottom surface 27 of the male pre-shaping part 26 and the bottom surface 22 of the female mould part 16 during pre-shaping of the cellulose blank 10 is equal to or less than fifteen times the distance between the bottom surface 19 of the male mould part 15 and the bottom surface 22 of the female mould part 16 during pressing of the cellulose blank 10 into final shape. Preferably the range is 10-13 times the distance between the bottom surface 19 of the male mould part 15 and the bottom surface 22 of the female mould part 16 during pressing of the cellulose blank 10. The thickness of the bottom of the final cellulose product 2 is usually in the range 0,6-0, 8 millimetres. Thereby the cellulose blank is not, or only insignificantly, compressed during the pre-shaping.
According to various embodiments, the distance between the wall surface 28 of the male pre-shaping part 26 and the wall surface 23 of the female mould part 16 during pre-shaping of the cellulose blank 10 is equal to or more than seven times the distance between the wall surface 20 of the male mould part 15 and the wall surface 23 of the female mould part 16 during pressing of the cellulose blank 10 into final shape. Thus, the minimum distance between the wall surface 28 of the male pre-shaping part 26 and the wall surface 23 of the female mould part 16 during the pre-shaping process step is always equal to or more than seven times the minimum distance between the wall surface 20 of the male mould part 15 and the wall surface 23 of the female mould part 16 during the pressing process step, i.e. when the male mould part 15 is at its bottom dead centre. Thereto, said distance between the wall surface 28 of the male pre-shaping part 26 and the wall surface 23 of the female mould part 16 during pre-shaping of the cellulose blank 10 is equal to or less than fifteen times the distance between the wall surface 20 of the male mould part 15 and the wall surface 23 of the female mould part 16 during pressing of the cellulose blank 10 into final shape. Preferably the range is 10-13 times the distance between the wall surface 20 of the male mould part 15 and the wall surface 23 of the female mould part 16 during pressing of the cellulose blank 10. The thickness of the wall of the final cellulose product 2 is usually in the range 0,6-0, 8 millimetres. Thereby the cellulose blank is not, or only insignificantly, compressed during the pre-shaping.
According to the invention, the male pre-shaping part 26, in connection with at least one of the bottom surface 27 and the transitional edge surface 29 thereof, comprises holding means, generally designated 30, configured for fixating the cellulose blank 10 in relation to the bottom surface 27 of the male pre-shaping part 26 during the insertion of the male pre-shaping part 26 into the main recess 17 of the female mould part 16. Thereby the cellulose blank 10 is prevented from material draw and elongation at the bottom region of the cellulose blank 10.
According to various embodiments, the holding means 30 of the male pre-shaping part 26 comprises a plurality of apertures 31 arranged in the at least one of the bottom surface 27 and the transitional surface 29 of the male pre-shaping part 26, and comprises a low-pressure chamber 32 arranged in fluid communication with said plurality of apertures 31. The low-pressure chamber 32 is preferably in fluid communication with at fan or the like equipment configured to generate under-pressure by removing air/gas from the low-pressure chamber 32. Preferably, the diameter of the respective aperture 31 is equal to or more than 0,5 mm and equal to or less than 4 mm, preferably equal to or more than 1 mm and equal to or less than 3 mm, preferably about 2 millimetre. The apertures 31 of the holding means 30 are in the disclosed embodiment arranged at the bottom surface 27 of the male pre-shaping part 26.
According to various non-disclosed embodiments, the holding means 30 of the male preshaping part 26 comprises a coarse surface area having a plurality of protrusions/pins configured to temporary engage the cellulose blank 10, at least one of the bottom surface 27 and the transitional surface 29 of the male pre-shaping part 26 comprising said coarse surface area. The advantage of fixating the cellulose blank 10 in relation to the bottom surface 27 of the male preshaping part 26 during pre-shaping by means of mechanical engagement is that it requires no energy.
After the pre-shaping of the cellulose blank 10, see the example embodiment of figure 3, the male pre-shaping part 26 is removed from the moulding tool and the cellulose blank 10 is pressed between the male mould part 15 and the female mould part 16 into final shape by applying the predetermined pressure P in the axial direction of the moulding tool according to figure 4. Thus, the main projection 18 of the male mould part 15 is inserted into the pre-shaped cellulose blank 10 and at the same time into the main recess 17 of the female mould part 16, wherein the wall 3 and bottom 6 of the cellulose product 2 are pressed.
After the pressing/forming step of the cellulose product 2, see the example embodiment of figure 5, the male mould part 15 and the female mould part 16 are disengaged, i.e. displaced in the axial direction away from each other, whereby the rigid cellulose product 2 may be removed/ejected from the moulding tool.
Reference is now made to figure 7. According to various embodiments, the male preshaping part 26 is part of a transfer means configured to provide the cellulose blank 10 into the moulding tool. Thus, the male pre-shaping part 26 engage/lifts the cellulose blank 10 outside the moulding tool and provides/transfer the cellulose blank 10 into the moulding tool, as a first substep. Thereafter the pre-shaping of the cellulose blank 10 takes place in the same way as described hereinabove, as a second sub-step.
According to non-disclosed embodiment, apertures 31 of the holding means 30 are arranged at the transitional edge surface 29 of the male pre-shaping part 26, alone or in addition to holding means 30 at the bottom surface 27 of the male pre-shaping part 26, in order to prevent the outer parts of the cellulose blank 10 to drop down and risk getting stuck somewhere during the transfer of the cellulose blank 10 into the moulding tool by means of the male pre-shaping part 26. Feasible modifications of the Invention
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.
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

Claims
1. Apparatus for dry manufacturing rigid cellulose products (2) having essentially non-flat general shape from a cellulose blank (10), the apparatus (1) comprising a moulding tool having a male mould part (15) and a female mould part (16) having co-operating designs, wherein at least one of the male mould part (15) and the female mould part (16) is displaceable in an axial direction in relation to the other in order to press the cellulose blank (10) therebetween into final shape by applying a predetermined pressure P in the axial direction of the moulding tool,
- wherein the female mould part (16) comprises a main recess (17) having a bottom surface (22), a wall surface (23) extending essentially in the axial direction, and a transitional edge surface (24) located between the bottom surface (22) and the wall surface (23), characterized in that the apparatus (1) further comprises a male pre-shaping part (26) configured for pre-shaping the cellulose blank (10) in the main recess (17) of the female mould part (16) before the pressing of the cellulose blank (10) into final shape, by insertion of the male preshaping part (26) into the main recess (17) of the female mould part (16) having the cellulose blank (10) located therebetween,
- wherein the male pre-shaping part (26) comprises a bottom surface (27), a wall surface (28) extending essentially in the axial direction, and a transitional edge surface (29) located between the bottom surface (27) and the wall surface (28), and
- wherein the male pre-shaping part (26), in connection with at least one of the bottom surface (27) and the transitional edge surface (29) thereof, comprises holding means (30) configured for fixating the cellulose blank (10) in relation to the bottom surface (27) of the male pre-shaping part (26) during the insertion of the male pre-shaping part (26) into the main recess (17) of the female mould part (16).
2. The apparatus according to claim 1, wherein the holding means (30) of the male pre-shaping part (26) comprises a plurality of apertures (31) arranged in the at least one of the bottom surface (27) and the transitional surface (29) of the male pre-shaping part (26), and comprises a low- pressure chamber (32) arranged in fluid communication with said plurality of apertures (31).
3. The apparatus according to claim 1, wherein the holding means (30) of the male pre-shaping part (26) comprises a coarse surface area having a plurality of protrusions configured to temporary engage the cellulose blank (10), at least one of the bottom surface (27) and the transitional surface (29) of the male pre-shaping part (26) comprising said coarse surface area.
4. The apparatus according to any of claims 1-3, wherein the distance between the bottom surface (27) of the male pre-shaping part (26) and the bottom surface (22) of the female mould part (16) during pre-shaping of the cellulose blank (10) in the main recess (17) of the female mould part (16) is equal to or more than seven times the distance between a bottom surface (19) of the male mould part (15) and the bottom surface (22) of the female mould part (16) during pressing of the cellulose blank (10) into final shape.
5. The apparatus according to any preceding claim, wherein the distance between the wall surface (28) of the male pre-shaping part (26) and the wall surface (23) of the female mould part (16) during pre-shaping of the cellulose blank (10) in the main recess (17) of the female mould part (16) is equal to or more than seven times the distance between a wall surface (20) of the male mould part (15) and the wall surface (23) of the female mould part (16) during pressing of the cellulose blank (10) into final shape.
6. The apparatus according to any preceding claim, wherein the male pre-shaping part (26) is part of a transfer means configured to provide the cellulose blank (10) into the moulding tool.
7. A method for dry manufacturing rigid cellulose products (2) having essentially non-flat general shape from a cellulose blank (10), the apparatus (1) comprising a moulding tool having a male mould part (15) and a female mould part (16) having co-operating designs, wherein at least one of the male mould part (15) and the female mould part (16) is displaceable in an axial direction in relation to the other in order to press the cellulose blank (10) therebetween into final shape by applying a predetermined pressure P in the axial direction of the moulding tool,
- wherein the female mould part (16) comprises a main recess (17) having a bottom surface (22), a wall surface (23) extending essentially in the axial direction, and a transitional edge surface (24) located between the bottom surface (22) and the wall surface (23), the method comprising the steps of:
- providing the cellulose blank (10) into the moulding tool,
- providing a male pre-shaping part (26) that comprises a bottom surface (27), a wall surface (28) extending essentially in the axial direction, and a transitional edge surface (29) located between the bottom surface (27) and the wall surface (28), wherein at least one of the bottom surface (27) and the transitional surface (29) of the male pre-shaping part (26) comprises holding means (30),
- pre-shaping the cellulose blank (10) in the main recess (17) of the female mould part (16) by inserting the male pre-shaping part (26) into the main recess (17) of the female mould part (16) having the cellulose blank (10) located therebetween,
- fixating the cellulose blank (10) in relation to the bottom surface (27) of the male pre-shaping part (26) during the insertion of the male pre-shaping part (26) into the main recess (17) of the female mould part (16) by means of said holding means (30), and
- pressing the cellulose blank (10) into final shape.
8. The method according to claim 7 , wherein the cellulose blank (10) is composed of an air-laid cellulose blank.
PCT/EP2024/076715 2023-09-25 2024-09-24 Apparatus and method for dry manufacturing rigid cellulose products Pending WO2025068140A1 (en)

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EP23199414.6 2023-09-25
EP23199414.6A EP4527610A1 (en) 2023-09-25 2023-09-25 Apparatus and method for dry manufacturing rigid cellulose products

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4648934A (en) * 1983-05-26 1987-03-10 Kiss G H Apparatus for three-dimensional moldings
CN208376102U (en) * 2018-04-26 2019-01-15 杭州中亚机械股份有限公司 A kind of carton extrusion molding apparatus
SE1851373A1 (en) * 2018-11-05 2020-05-06 Pulpac AB Forming mold system and method for forming three-dimensional cellulose products
ES2903264B2 (en) * 2020-09-29 2023-02-14 Telesforo Gonzalez Maqu Slu MACHINE FOR THE FORMATION OF BOXES, INTENDED TO BE NESTED AND WITH EDGES LOCATED IN THE UPPER PART OF THE SIDE WALLS OF THE SAME AND FOLDED TO THE OUTSIDE OF THESE

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4648934A (en) * 1983-05-26 1987-03-10 Kiss G H Apparatus for three-dimensional moldings
CN208376102U (en) * 2018-04-26 2019-01-15 杭州中亚机械股份有限公司 A kind of carton extrusion molding apparatus
SE1851373A1 (en) * 2018-11-05 2020-05-06 Pulpac AB Forming mold system and method for forming three-dimensional cellulose products
ES2903264B2 (en) * 2020-09-29 2023-02-14 Telesforo Gonzalez Maqu Slu MACHINE FOR THE FORMATION OF BOXES, INTENDED TO BE NESTED AND WITH EDGES LOCATED IN THE UPPER PART OF THE SIDE WALLS OF THE SAME AND FOLDED TO THE OUTSIDE OF THESE

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