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EP-4209634-B1 - A METHOD FOR FORMING CELLULOSE PRODUCTS IN A FORMING MOULD SYSTEM FROM A CELLULOSE BLANK STRUCTURE, A FORMING MOULD SYSTEM, AND A CELLULOSE BLANK STRUCTURE

EP4209634B1EP 4209634 B1EP4209634 B1EP 4209634B1EP-4209634-B1

Inventors

  • LARSSON, OVE
  • GUIDOTTI, EDWARD
  • HÖGBLOM, Olle

Dates

Publication Date
20260506
Application Date
20210118

Claims (20)

  1. A method for providing an air-formed cellulose blank structure (2) for forming cellulose products (1) in a forming mould system (S), wherein the method comprises the steps: providing the cellulose blank structure (2), and in the cellulose blank structure (2) defining one or more product sections (2a) and a residual section (2b) surrounding or arranged in connection to the one or more product sections (2a); compressing at least a portion of the residual section (2b) to a first degree of compression (D C1 ) higher than a degree of compression (D C ) of the one or more product sections (2a); wherein the cellulose blank structure (2) further comprises one or more transition sections (2c) arranged between the one or more product sections (2a) and the residual section (2b), wherein in the one or more transition sections (2c) the degree of compression is varying between the first degree of compression (D C1 ) and the degree of compression (D C ) of the one or more product sections (2a).
  2. The method according to claim 1, wherein the method further comprises the step: compressing at least a portion of the one or more product sections (2a) to a second degree of compression (D C2 ) prior to the feeding of the cellulose blank structure (2) to the forming position (F POS ), wherein the first degree of compression (D C1 ) is higher than the second degree of compression (D C2 ).
  3. The method according to claim 1 or 2, wherein the method further comprises the step: in the forming position (F POS ) at least partly displacing the residual section (2b) and the one or more product sections (2a) relative to each other in a pressing direction (D P ) of the forming mould system (S) prior to the forming of the cellulose products (1).
  4. The method according to any of claims 1 to 3, wherein the method further comprises the step: arranging a cutting pattern (4) in the residual section (2b) and/or the transition section (2c) at least partly around each product section (2a); wherein each cutting pattern (4) is forming at least one bridging structure (4a) in the residual section (2b) and/or the transition section (2c) for keeping each product section (2a) partly connected with the residual section (2b) and/or the transition section (2c).
  5. The method according to claim 4, wherein each cutting pattern (4) comprises a non-continuous first cut (5) arranged around and in connection to a corresponding product section (2a), wherein the non-continuous first cut (5) comprises one or more first cut lines (5a) with one or more first intermediate sections (5b) between the one or more first cut lines (5a), wherein the one or more first intermediate sections (5b) are forming the at least one bridging structure (4a).
  6. The method according to claim 4, wherein each cutting pattern (4) comprises a first cut (5) arranged around and in connection to a corresponding product section (2a), wherein the first cut (5) comprises a first cut line (5a) with a first intermediate section (5b) forming the at least one bridging structure (4a).
  7. The method according to claim 4, wherein each cutting pattern (4) comprises a non-continuous first cut (5) arranged around and in connection to a corresponding product section (2a), and a non-continuous second cut (6) arranged around and outwards of the non-continuous first cut (5) relative to the product section (2a).
  8. The method according to claim 7, wherein the non-continuous first cut (5) comprises one or more first cut lines (5a) with one or more first intermediate sections (5b) between the one or more first cut lines (5a), wherein the non-continuous second cut (6) comprises one or more second cut lines (6a) with one or more second intermediate sections (6b) between the one or more second cut lines (6a), wherein the one or more first intermediate sections (5b) and the one or more second intermediate sections (6b) are forming the at least one bridging structure (4a).
  9. The method according to claim 8, wherein the non-continuous first cut (5) and the non-continuous second cut (6) are arranged in an overlapping relationship relative to each other, wherein the one or more first cut lines (5a) are overlapping the one or more second intermediate sections (6b), and wherein the one or more second cut lines (6a) are overlapping the one or more first intermediate sections (5b).
  10. The method according to any of claims 7 to 9, wherein each cutting pattern (4) further comprises at least one non-continuous additional cut (7) arranged around and outwards of the non-continuous second cut (6) relative to the product section (2a), wherein each of the at least one non-continuous additional cut (7) comprises one or more additional cut lines (7a) with one or more additional intermediate sections (7b) between the one or more additional cut lines (7a).
  11. The method according to any of claims 5 to 10, wherein each cut (5, 6, 7) is extending through the cellulose blank structure (2).
  12. The method according to any of claims 5 to 11, wherein at least one of the intermediate sections (5b, 6b, 7b) comprise a cut extending partly through the cellulose blank structure (2).
  13. The method according to any of claims 4 to 12, wherein the method further comprises the step: arranging the one or more cutting patterns (4) in the residual section (2b) and/or the transition section (2c) around each product section (2a) with a cutting unit (9).
  14. The method according to claim 13, wherein the cutting unit (9) is arranged as a rotary die cutter (10), wherein the method further comprises the step: forming the one or more cutting patterns (4), and compressing at least a part of the residual section (2b) with the rotary die cutter (10) in a single operational step; or forming the one or more cutting patterns (4), compressing at least a part of the residual section (2b), and compressing at least a portion of the one or more product sections (2a) with the rotary die cutter (10) in a single operational step.
  15. The method according to any preceding claim, wherein the method further comprises the steps: forming cellulose products (1) in a forming mould system (S) from the air-formed cellulose blank structure (2), wherein the forming mould system (S) comprises one or more forming moulds (3), wherein each forming mould (3) comprises a first mould part (3a) and a second mould part (3b) configured for cooperating with each other during the forming of the cellulose products (1); feeding the cellulose blank structure (2) in a feeding direction (D F ) to a forming position (F POS ) in the forming mould system (S), wherein in the forming position (F POS ) each product section (2a) is arranged between a corresponding first mould part (3a) and second mould part (3b); forming the cellulose products (1) from the cellulose blank structure (2) between the first mould part (3a) and the second mould part (3b) by heating the cellulose blank structure (2) to a forming temperature (T F ) in the range of 100-300 °C; and pressing the cellulose blank structure (2) with a forming pressure (P F ) in the range of 1-100 MPa, preferably 4-20 MPa.
  16. The method according to claim 15, wherein the method further comprises the step: cutting out the cellulose products (1) from the cellulose blank structure (2) in the forming mould system (S) during forming of the cellulose products (S).
  17. The method according to claim 15 or 16, wherein the one or more product sections (2a) are arranged in the cellulose blank structure (2) in a pattern corresponding to the arrangement of the one or more forming moulds (3) in the forming mould system (S).
  18. A forming mould system (S) for forming cellulose products (1) from an air-formed cellulose blank structure (2) comprising one or more defined product sections (2a) and a defined residual section (2b) surrounding or arranged in connection to the one or more product sections (2a), wherein the forming mould system (S) comprises one or more forming moulds (3), wherein each forming mould (3) comprises a first mould part (3a) and a second mould part (3b) configured for cooperating with each other during the forming of the cellulose products (1), wherein the forming mould system (S) further comprises: a compacting unit (11) configured for compressing at least a portion of the residual section (2b) to a first degree of compression (D C1 ) higher than a degree of compression (D C ) of the one or more product sections (2a); and a feeding unit (8) configured for feeding the cellulose blank structure (2) in a feeding direction (D F ) to a forming position (F POS ) in the forming mould system (S), wherein in the forming position (F POS ) each product section (2a) is arranged between a corresponding first mould part (3a) and second mould part (3b); wherein the one or more forming moulds (3) are configured for: forming the cellulose products (1) from the cellulose blank structure (2) between the first mould part (3a) and the second mould part (3b) by heating the cellulose blank structure (2) to a forming temperature (T F ) in the range of 100-300 °C; and pressing the cellulose blank structure (2) with a forming pressure (P F ) in the range of 1-100 MPa, preferably 4-20 MPa.
  19. A cellulose blank structure (2) for forming cellulose products (1) in a forming mould system (S), wherein the cellulose blank structure (2) is air-formed and comprises one or more defined product sections (2a) and a defined residual section (2b) surrounding or arranged in connection to the one or more product sections (2a), wherein at least a portion of the residual section (2b) has a first degree of compression (D C1 ) higher than a degree of compression (D C ) of the one or more product sections (2a), wherein the cellulose blank structure (2) further comprises: one or more transition sections (2c) arranged between the one or more product sections (2a) and the residual section (2b), wherein in the transition section (2c) the degree of compression is varying between the first degree of compression (D C1 ) and the degree of compression (D C ) of the one or more product sections (2a).
  20. A cellulose blank structure (2) according to claim 19, wherein the cellulose blank structure (2) further comprises a cutting pattern (4) in the residual section (2b) and/or the transition section (2c) at least partly around each product section (2a); wherein each cutting pattern (4) is forming at least one bridging structure (4a) in the residual section (2b) and/or the transition section (2c).

Description

TECHNICAL FIELD The present disclosure relates to a method for forming cellulose products in a forming mould system from an air-formed cellulose blank structure. The forming mould system comprises one or more forming moulds, wherein each forming mould comprises a first mould part and a second mould part configured for cooperating with each other during the forming of the cellulose products. The disclosure further relates to a forming mould system and a cellulose blank structure. BACKGROUND Cellulose fibres are often used as raw material for producing or manufacturing products. Products formed of cellulose fibres can be used in many different situations where there is a need for having sustainable products. A wide range of products can be produced from cellulose fibres and a few examples are disposable plates and cups, cutlery, lids, bottle caps, coffee pods, and packaging materials. Forming moulds are commonly used when manufacturing cellulose products from raw materials including cellulose fibres, and traditionally the cellulose products have been produced with wet-forming techniques. A material commonly used for wet-forming cellulose fibre products is wet moulded pulp. Wet moulded pulp has the advantage of being considered as a sustainable packaging material, since it is produced from biomaterials and can be recycled after use. Consequently, wet moulded pulp has been quickly increasing in popularity for different applications. Wet moulded pulp articles are generally formed by immersing a suction forming mould into a liquid or semi liquid pulp suspension or slurry comprising cellulose fibres, and when suction is applied, a body of pulp is formed with the shape of the desired product by fibre deposition onto the forming mould. With all wet-forming techniques, there is a need for drying of the wet moulded product, where the drying is a very time and energy consuming part of the production. The demands on aesthetical, chemical and mechanical properties of cellulose products are increasing, and due to the properties of wet-formed cellulose products, the mechanical strength, flexibility, freedom in material thickness, and chemical properties are limited. It is also difficult in wet-forming processes to control the mechanical properties of the products with high precision. One development in the field of producing cellulose products is the forming of cellulose fibres without using wet-forming techniques. Instead of forming the cellulose products from a liquid or semi liquid pulp suspension or slurry, an air-formed cellulose blank structure is used. The air-formed cellulose blank structure is inserted into a forming mould and during the forming of the cellulose products the cellulose blank is subjected to a high forming pressure and a high forming temperature. A respective method is disclosed in WO 2019/209160. When inserting the cellulose blank structure into the forming mould, there is a risk that the cellulose blank structure breaks apart in an undesired manner, which leads to an improper forming of the cellulose products. This is a common issue with traditional cellulose high pressure forming methods, especially for deep-drawn products, leading to products with low quality. Other problems with traditional forming methods using standard cellulose blank structures, especially when forming deep-drawn products, are that that cracks, fibre separations, material fractures, or other unwanted structural weakenings of the cellulose blank structure are occurring during the insertion of the cellulose blank structure into the forming mould and during the forming process in the forming mould. There is thus a need for an improved method, forming mould system, and cellulose blank structure, for forming cellulose products from an air-formed cellulose blank structure. SUMMARY An object of the present invention is to provide a method for forming cellulose products in a forming mould system from a cellulose blank structure, a forming mould system, and a cellulose blank structure, where the previously mentioned problems are avoided. This object is achieved by the features of the independent claims. The dependent claims contain further developments of the method for forming cellulose products in a forming mould system from a cellulose blank structure. In particular, the invention concerns a method for forming cellulose products in a forming mould system from an air-formed cellulose blank structure. The forming mould system comprises one or more forming moulds, wherein each forming mould comprises a first mould part and a second mould part configured for cooperating with each other during the forming of the cellulose products. The method comprises the steps: providing the cellulose blank structure, and in the cellulose blank structure defining one or more product sections and a residual section surrounding or arranged in connection to the one or more product sections; compressing at least a portion of the residual section to a fir