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
  • 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
  • B31B50/74—Auxiliary operations
  • B31B50/88—Printing; Embossing
• • 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
  • 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
  • B31F1/07—Embossing, i.e. producing impressions formed by locally deep-drawing, e.g. using rolls provided with complementary profiles
• • 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
  • B65D1/22—Boxes or like containers with side walls of substantial depth for enclosing contents
  • B65D1/26—Thin-walled containers, e.g. formed by deep-drawing operations
• • 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
  • B31B2110/00—Shape of rigid or semi-rigid containers
  • B31B2110/10—Shape of rigid or semi-rigid containers having a cross section of varying size or shape, e.g. conical or pyramidal
• • 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
  • B31F2201/00—Mechanical deformation of paper or cardboard without removing material
  • B31F2201/07—Embossing
  • B31F2201/0702—Embossing by tools working discontinuously

Definitions

• the present invention relates in general to the field of method and apparatus for dry manufacturing of rigid cellulose products having essentially 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 product forming unit are especially defined to provide rigid cellulose products having decorative and/or functional small-pattern on the pressed surface(s) of thinn cellulose products.
• the term cellulose products means products that mainly consists of the cellulose part of organic matter.
• the present invention relates specifically to a product forming unit and a method for dry manufacturing rigid cellulose products, the product forming unit comprising a moulding tool having a first mould part and a second mould part, 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 therebetween into final shape by applying a predetermined pressure P in the axial direction of the moulding tool, wherein the first mould part comprises a product press-surface having an essentially even principal surface and the second mould part comprises a product press-surface having an essentially even principal surface, and wherein a nominal distance (T) between the principal surface of the first mould part and the principal surface of the second mould part, when located in a press-position during pressing of the cellulose blank, is in the range 0,3-2,0 millimetres.
• T nominal distance
• 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.
• the moulding tool is usually made of a wire netting/cloth that is filled with a wet cellulose slurry and thereafter the cellulose slurry is dried and obtains the general shape of the moulding tool.
• 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.
• 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.
• the cellulose product obtains a debossing pattern from the wire netting/cloth on the entire surface of one of the sides of the cellulose product, and the opposite side of the cellulose product is quite rough and un-even.
• 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 thermo-forming press.
• a too high pressing force entails that the pressed cellulose product will become brittle/plastic and thereto the final cellulose product obtains a yellow tone, i.e. too high density.
• a too low pressing force entails that the pressed cellulose product becomes insufficiently moulded, i.e. the internal bonding between the cellulose fibres becomes inadequate, and there will be a great degree of fibre release from the surfaces, i.e. too low density.
• the applied pressure and the surface weight of the cellulose blank provides a nominal thickness of the pressed cellulose product having an optimal density.
• the male mould part and the female mould part has to have co-operating design, i.e. one of the mould parts comprises a local projection and the other mould part comprises a local recess, in order to obtain the nominal thickness and thereby the correct material characteristics over the entire cellulose product.
• the pattern has to be wide/broad enough such that the projection and the recess of the mould parts may cooperate.
• the present invention aims at obviating the aforementioned and other disadvantages and failings of previously known methods and devices for dry manufacturing rigid cellulose products, and at providing an improved method and product forming unit for dry manufacturing rigid cellulose products having non-flat general shape and decorative and/or functional small-pattern.
• a primary object of the present invention is to provide an improved product forming unit and method for dry forming/manufacturing rigid cellulose products having non-flat general shape and decorative and/or functional small-pattern, 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 product forming unit and method for dry forming/manufacturing rigid cellulose products having non-flat general shape, wherein the pressed cellulose product has uniform material characteristics.
• a product forming unit of the initially defined type wherein the first mould part comprises:
• a method for dry manufacturing rigid cellulose products having essentially non-flat general shape from a cellulose blank using a product forming unit as defined herein above wherein the method comprises the steps of:
• the present invention is based on the insight that the height and depth of the pattern in relation to the principal surface of the pressed cellulose product may only differ up to 15% of the nominal thickness of the pressed cellulose product, in order not to suffer from fibre release and yellow tone, respectively.
• the inventor has realized that there is a correlation between the nominal thickness of the pressed cellulose product and the possible height and depth of the pattern.
• the total amplitude of the final pattern of the pressed cellulose product may be twice as high compared to only having debossing or embossing, without suffering from fibre release and/or yellow tone.
• the height (H) of the projection is equal to or more than 0,02 millimetres, and/or, the depth (D) of the recess is equal to or more than 0,02 millimetres.
• the depth (D) of the recess is equal to or more than 0,02 millimetres.
• said predetermined pressure P used during pressing of the cellulose blank is configured to generate a density of the pressed cellulose product that is equal to or more than 1035 kg/m 3 and equal to or less than 1265 kg/m 3 . Thereby, the pressed cellulose product will not suffer from yellow tone and/or fibre release.
• the height (H) of the projection of the first mould part is equal to or less than the smaller of 15% of the nominal distance (T) and 0,2 millimetres, and/or, the depth (D) of the recess of the first mould part is equal to or less than the smaller of 15% of the nominal distance (T) and 0,2 millimetres.
• the maximum height and depth of the pattern is given by a specific metric dimension instead of a percentage.
• 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, generally designated 1, for dry manufacturing rigid cellulose products.
• 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 5 disclose an example of a rigid cellulose product/tray 2.
• the apparatus 1 may have automatic transfer/handling between the different process steps, and/or may have manual transfer/handling between the different process steps, and thereto the apparatus 1 may have intermediate storing and/or additional process steps between the disclosed process steps, and/or the process steps may be located at different sites.
• Figure 5 disclose one example of a rigid cellulose product 2 constituted by a rectangular container/tray, wherein the tray is formed using the inventive method.
• the cellulose product 2 comprises an inclined circumferential wall 3 and an opening 4 defined by a circumferential rim/brim 5 connected to the upper/free end of the 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 5 embodiment.
• the tray 2 may for instance have curved-shaped wall 3 seen in the axial plane.
• the tray could also be a mug/cup, a lid, packaging or the like container/product.
• 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 bottom 6, wherein the bottom 6 is entirely flat or the bottom may comprise local ribs, projections, etc., for strength and rigidity of the cellulose product.
• the bottom 6 may be located at the very lower end of the wall 3, according to figure 5 embodiment, and/or be partly located at a distance from the lower end of the wall 3, or a combination thereof.
• the circumferential wall 3 is connected to and extends in the axial direction upwards from the bottom portion 6.
• 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.
• 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.
• said separating unit 8 the cellulose raw material is separated into fibres having a normal length in the range of 0,5-70 mm, preferably less than 10 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 7.
• 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 pre-heating 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 order to exert pressure to the cellulose blank 10 loaded therebetween.
• the mutual displacement 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 first mould part 15 of the moulding tool is a female mould part, i.e. having a main recess 17 for receiving a major part of the cellulose blank 10
• the second mould part 16 of the moulding tool is a male mould part, i.e. having a main protrusion 18 for cooperation with said recess 17 of the female mould part by being inserted therein, such that the cellulose blank 10 is pressed into a final rigid non-flat shape by applying a predetermined pressure P in the axial direction of the moulding tool.
• the male/second mould part 16 is located above the female/first mould part 15, i.e.
• the pressed cellulose product 2 is intended to be collected from the female/first mould part 15 after the pressing of the cellulose blank 10.
• the female/first mould part 15 may be located above the male/second mould part 16, i.e. the pressed cellulose product 2 is intended to be collected from the male/second mould part 15 after the pressing of the cellulose blank 10.
• the first mould part is constituted by a male mould part and the second mould part is constituted by a female mould part.
• the second mould part 16 comprises a product press-surface and a scrap press-surface 19 adjacent said product press-surface.
• the product press-surface of the second mould part 16 comprises a bottom surface 20, a wall surface 21 connected to the bottom surface 20 and extending essentially in the axial direction, and a brim surface 22 connected to the wall surface 21 and extending essentially in the transversal/radial direction.
• the scrap press-surface 19 of the second mould part 16 surrounds the entire product press-surface.
• the scrap press-surface 19 of the second mould part 16 is only located at some locations around the product press-surface.
• the first mould part 15 comprises a product press-surface and a scrap press-surface 23 adjacent said product press-surface.
• the product press-surface of the first mould part 15 comprises a bottom surface 24, a wall surface 25 connected to the bottom surface 24 and extending essentially in the axial direction, and a brim surface 26 connected to the wall surface 25 and extending essentially in the transversal/radial direction.
• the scrap press-surface 23 of the first mould part 15 surrounds the entire product press-surface. According to other embodiments, the scrap press-surface 23 of the first mould part 15 is only located at some locations around the product press-surface.
• some moulding tools does not comprise scrap press-surfaces, but the cellulose product 2 is formed in its final design without need for cutting/trimming.
• the scrap press-surface 23 of the first mould part 15 is arranged opposite the scrap press-surface 19 of the second mould part 16, and the product press-surface of the first mould part 15 is arranged opposite the product press-surface of the second mould part 16.
• the cellulose blank 10 is pressed between the surfaces of the male/second mould part 16 and the surfaces of the female/first mould part 15 into final shape.
• the mutual distance, taken perpendicular to the surface in question, between the product press-surface of the female/first mould part 15 and the product press-surface of the male/second mould part 16 during the pressing of the cellulose blank 10 is T millimetres, wherein T preferably is in the range 0,3-2,0 millimetres, i.e. equal to the thickness of the bottom 6 of the pressed cellulose product 2.
• T is in the range 0,3-1,5 millimetres, and most preferably below 1,0 millimetres in order to save raw material.
• the wall surfaces 21, 25 of the moulding tool has to be inclined in order to obtain a release angle for the cellulose product, and in order to obtain adequate press force to the wall region 3 of the cellulose product 2.
• the mutual distance between the scrap press-surface 23 of the first mould part 15 and the scrap press-surface 19 of the second mould part 16 is equal to or more than the mutual distance between the product press-surface of the first mould part 15 and the product press-surface of the second mould part 16.
• the part of the cellulose blank 10 located at 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.
• the cellulose blank 10 comprises a scrap area intended to be cut off.
• the cellulose product 2 is released and schematically removed from the moulding tool by opening the moulding tool.
• Figure 5 disclose a schematic illustration of a cellulose tray 2 wherein the scrap 27 is cut off from the cellulose tray 2.
• the scrap 27 may be removed in a separate step in the moulding tool, in a subsequent step outside the moulding tool after the pressing of the cellulose blank 10, or in a step concurrent with the pressing of the cellulose blank 10.
• a film/cover/lid may be attached to the circumferential rim/brim 5 of the cellulose tray 2, for instance using heat lamination.
• the lid film may be constituted by a multilayer film comprising polymer, metal, and/or paper.
• the rigid cellulose tray 2 Before any items are placed in the compartment of the rigid cellulose tray, the rigid cellulose tray 2 may be provided with a liner film adhered to at least to the circumferential rim/brim 5, and preferably also to the wall 3 and/or the bottom 6 of the cellulose tray 2.
• the liner film may be constituted by a multilayer film comprising polymer and/or metal. The adhesion of the liner film to the tray is preferably heat activated.
• the cellulose blank 10 may comprise barrier additives and/or material property enhancing additives, etc., such that the rigid cellulose tray 2 withstand grease, fat, water, vapour, etc.
• the additives are preferably provided to the cellulose fibers upstream the disintegrating unit 8 or between the disintegrating unit 8 and the product forming unit 11.
• 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.
• FIG 6 disclosing a first schematic embodiment of the present invention, wherein the female mould part is the first mould part 15, and to figure 7 disclosing a second schematic embodiment of the present invention, wherein the male mould part is the first mould part 15.
• the figures are not drawn to scale.
• the product press-surface of the first mould part 15 has an essentially even/smooth principal/main surface 28 and the product press-surface of the second mould part 16 has an essentially even/smooth principal/main surface 29.
• the principal surfaces 28, 29 of the two mould parts are appropriately machined/polished in order to obtain the requested surface roughness/smoothness of the pressed cellulose product 2.
• the principal surfaces 28, 29 of the mould parts does not need to be a flat surface, but may as well be a single curved or double curved surface.
• the nominal distance (T) between the principal surface 28 of the first mould part 15 and the principal surface 29 of the second mould part 16, when located in a press-position during pressing of the cellulose blank 10, is in the range 0,3-2,0 millimetres, preferably in the range 0,3-1,5 millimetres, and most preferably less than 1,0 millimetres.
• the thickness of the pressed cellulose product 2 is equal to said nominal distance (T), and it is preferred to have as thin cellulose product 2 as possible in order to save cellulose raw material, as long as the mechanical characteristics of the cellulose product 2 are fulfilled.
• the first mould part 15 comprise at least one projection 30 that is provided to the principal surface 28 and has a height (H) measured in relation to the surrounding parts of the principal surface 28 of the first mould part 15.
• the height (H) of the at least one projection 30 is equal to or less than 15% of the nominal distance (T) between the principal surface 28 of the first mould part 15 and the principal surface 29 of the second mould part 16, when located in a press-position during pressing of the cellulose blank 10.
• said at least one projection 30 provides a debossing pattern 31 on the pressed cellulose product 2.
• the depth of the debossing is equal to or less than 15% of the nominal thickness (T) of the pressed cellulose product 2.
• the height (H) of the at least one projection 30 is equal to or less than 10% of the nominal distance (T) between the principal surface 28 of the first mould part 15 and the principal surface 29 of the second mould part 16. Thereby, it is by margin secured that the cellulose product 2 is not over-pressed at the location of the debossing pattern 31.
• the first mould part 15 comprise at least one recess 32 that is provided to the principal surface 28 and has a depth (D) measured in relation to the surrounding parts of the principal surface 28 of the first mould part 15.
• the depth (D) of the at least one recess 32 is equal to or less than 15% of the nominal distance (T) between the principal surface 28 of the first mould part 15 and the principal surface 29 of the second mould part 16, when located in a press-position during pressing of the cellulose blank 10.
• said at least one recess 32 provides an embossing pattern 33 on the pressed cellulose product 2.
• the height of the embossing is equal to or less than 15% of the nominal thickness (T) of the pressed cellulose product 2.
• the depth (D) of the at least one recess 32 is equal to or less than 10% of the nominal distance (T) between the principal surface 28 of the first mould part 15 and the principal surface 29 of the second mould part 16. Thereby, it is by margin secured that the cellulose product 2 is not under-pressed at the location of the embossing pattern 33.
• the total pattern on the pressed cellulose product 2 has the amplitude of the sum of the height (H) of the debossing pattern 31 and the depth (D) of the embossing pattern 33, at the same time as optimal pressing of the cellulose product 2 is provided also at the locations of the total pattern.
• the total pattern may be decorative/figurative and/or functional/informative.
• the essentially even principal surface 29 of the second mould part 16 is opposite said projection 30 of the first mould part 15 and opposite said recess 32 of the first mould part 15.
• the total pattern is provided by the projection 30 and recess 32 as such, without any corresponding design features on the second mould part 16.
• the first mould part 15 is a female mould part
• the debossing pattern 31 and the embossing pattern 33 of the cellulose product 2 are located on the lower side of the bottom 6 of the cellulose product 2.
• the first mould part 15 is a male mould part
• the debossing pattern 31 and the embossing pattern 33 of the cellulose product 2 are located on the upper side of the bottom 5 of the cellulose product 2.
• the height (H) of the at least one projection 30 is equal to or more than 0,02 millimetres. This will result in a debossing pattern 31 that is visible by the naked eye, and provides a clear and distinct difference in relation to general surface roughness of the principal surface 28 of the first mould part 15.
• the depth (D) of the at least one recess 32 is equal to or more than 0,02 millimetres. This will result in an embossing pattern 33 that is visible by the naked eye, and provides a clear and distinct difference in relation to general surface roughness of the principal surface 28 of the first mould part 15.
• the nominal thickness (T) of the pressed cellulose product 2 is related to the grammage of the cellulose blank 10 and the predetermined pressure P used during pressing of the cellulose blank 10.
• the predetermined pressure P used during pressing of the cellulose blank 10 is configured to generate a density of the pressed cellulose product 2 that is equal to or more than 1035 kg/m 3 and equal to or less than 1265 kg/m 3 . Thereby it is secured that no part of the cellulose product 2 is over-pressed or under-pressed, including the debossing pattern 31 and the embossing pattern 33 generated by the projection 30 and recess 32 of the first mould part 15.
• the generated density of the pressed cellulose product 2 is equal to or more than 1100 kg/m 3 and equal to or less than 1200 kg/m 3 , and the target density is 1150 kg/m 3 .
• the target density is 1150 kg/m 3 .
• the principal surface 28 of the first mould part 15 is made of metal and the principal surface 29 of the second mould part 16 is made of an elastic material, such as rubber. According to other various embodiments, both the principal surface 28 of the first mould part 15 and the principal surface 29 of the second mould part 16 are made of metal.
• At least 50 % of the product press-surface of the first mould part 15 is constituted by the principal/main surface 28, i.e. free from projections 30 and recesses 32.
• the principal surface 28 of the first mould part 15 is located between and separates the projection 30 of the first mould part 15 and the recess 32 of the first mould part 15, i.e. the debossing pattern 31 and the embossing pattern 33 are not directly adjacent each other.
• the height (H) of the at least one projection 30 of the first mould part 15 is equal to or less than the smaller of 15% of the nominal distance (T) and 0,2 millimetres.
• the height (H) of the at least one projection 30 is delimited to 0,2 millimetres, in order to secure that the cellulose product 2 is not over-pressed at the location of the debossing pattern 31.
• the depth (D) of the at least one recess 32 of the first mould part 15 is equal to or less than the smaller of 15% of the nominal distance (T) and 0,2 millimetres.
• the depth (D) of the at least one recess 32 is delimited to 0,2 millimetres, in order to secure that the cellulose product 2 is not under-pressed at the location of the embossing pattern 33.
• the second mould part 16 comprises at least one projection and/or at least one recess provided to the principal surface 29 of the second mould part 16.
• the essentially even principal surface 28 of the first mould part 15 is opposite such projections of the second mould part 16 and/or opposite such recesses of the second mould part 16.
• Such projections and recesses of the second mould part 16 are configured in accordance with the projections 30 and recesses 32 of the first mould part 15.
• the method comprises the steps of:

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Citations (5)

• 2024
  • 2024-05-14 EP EP24175575.0A patent/EP4650161A1/fr active Pending
• 2025
  • 2025-05-12 WO PCT/EP2025/062881 patent/WO2025237892A1/fr active Pending

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