Method for manufacturing an article by compression and multilayer element

Abstract

A method of manufacturing a product (P), wherein said method comprises the steps of: preparing a multilayer element (1) comprising at least 80% of a non-extruded material (2) in solid phase and comprising at least one layer (2) which is barrier to liquids and / or oxygen; housing the multilayer element (1) in a mould (100) between a female portion (101) defining a forming cavity (102) and a punch (103) movable along a first longitudinal axis (X); compressing the multilayer element (1) by displacing the punch (103) towards a bottom wall (102a) of the cavity (102); and moving at least one lateral slide (104) of the female portion (101) defining the forming cavity (102) towards said punch (103); the step of moving the lateral slide (104) is performed so as to compress the multilayer element (1) between the slide (104) itself and the punch (103).

Description

Technical Field

[0001] This invention relates to a method for manufacturing various types of products by compression molding of multilayer elements. The invention also relates to a multilayer element suitable for compression molding to manufacture articles. Background Technology

[0002] As is well known, environmental regulations increasingly favor the use of natural and compostable materials, which are often based on plant fibers or bacterial substances. These materials are used to manufacture items such as containers, especially for food and beverages, and capsules, caps, or bottles for coffee.

[0003] Natural fiber-based materials are shaped using specific methods, typically compression molding.

[0004] In reality, plant fiber-based or bacteria-based materials (such as cellulose) cannot be formed using extrusion technology, which requires heating the material to very high temperatures. Overheating cellulose materials in this way can burn the fibers, thus damaging the material itself.

[0005] For this reason, the cellulose is prepared in "dosage" form and compressed within a mold to obtain the desired shape. If necessary, the dosage can be heated to facilitate forming by compression, but the temperature must be controlled at values ​​far below those of known extrusion techniques.

[0006] Cellulose dosage can also be in the form of parts obtained by cutting a continuous web and appropriately conveyed to the molding equipment.

[0007] The dosage can preferably be formed separately, thereby advantageously eliminating processing waste / garbage.

[0008] Alternatively, cellulose materials can be transported in the form of a continuous membrane through a relevant compression molding station.

[0009] However, the nature of plant fiber-based materials means that the production technology is limited to certain items.

[0010] It should be noted that cellulose is known to be hydrophilic, and therefore, if articles are to be made that are intended to come into contact with water and moisture, they must be bound to a membrane (hydrophobic material) that can block water.

[0011] However, although the multi-layered components obtained in this way can block both oxygen and water, they still have significant limitations in the relevant molding process.

[0012] In practice, molding involves a step of compressing the dose between the punch portion and the die portion inserted into the defining molding chamber. This compression step applies a deep-drawing action to the dose, which stretches the fiber until it reaches the desired final shape.

[0013] In this context, it should be noted that, especially for objects of greater depth, the barrier membranes bound to cellulose materials may be overstretched and torn.

[0014] It should also be considered that, in order to obtain compostable dosages, the amount / thickness of hydrophobic barrier films, such as those made of thermoplastic polymers, used is very limited compared to the thickness of cellulose.

[0015] Therefore, although cellulose is easier to shape and stretch during the compression step, partly because a larger amount of material can be used in a single dose, the barrier membrane is thinner and therefore more fragile and easily damaged.

[0016] For this reason, compostable feedstocks with water-blocking membranes have significant limitations in the compression molding process, especially when making deeper products.

[0017] It should also be noted that using thicker barrier films, which are therefore better able to withstand stretching steps, can impair the biodegradability of the final product and increase the production cost of the product itself. Summary of the Invention

[0018] Therefore, the object of the present invention is to provide a multilayer element and method for manufacturing articles by compression molding without the aforementioned disadvantages.

[0019] Specifically, the first object of the present invention is to provide a multi-layer element for manufacturing articles by compression molding, the multi-layer element being compostable and simultaneously effective in blocking oxygen, water, steam, fragrance or grease.

[0020] More specifically, one object of the present invention is to provide a multilayer element that is versatile, inexpensive, applicable in many fields requiring the barrier of oxygen and water, and suitable for manufacturing products by compression molding, which requires stretching the material constituting the element to a large depth.

[0021] Another object of the present invention is to provide a method for manufacturing various types of products, which is capable of compression molding of multilayer components.

[0022] In particular, another object of the present invention is to provide a compression molding method that can maintain the integrity of the materials constituting multilayer elements, especially in the element stretching and deep drawing steps.

[0023] In a first aspect of the invention, a multilayer element is provided for manufacturing articles by compression molding, wherein the multilayer element comprises at least 80% of a non-extrudable material in a solid phase and at least one layer capable of blocking liquids and / or oxygen.

[0024] Advantageously, non-extruded materials are natural fiber-based materials, especially cellulose-based materials.

[0025] Even more preferably, the non-extruded material is an airflow mesh material with a thickness greater than that of the barrier layer.

[0026] According to another aspect of the invention, the barrier layer is positioned on at least one outer surface of the non-extruded material and / or disposed inside the material.

[0027] The barrier layer is preferably made of thermoplastic film, and its thickness is much smaller than that of non-extruded materials.

[0028] According to another aspect of the invention, a method for manufacturing a product is provided, wherein the method comprises the steps of: preparing a multilayer element of the type described above, accommodating the multilayer element in a mold such that it is positioned between a die portion defining a molding cavity and a punch movable along a first longitudinal axis; compressing the multilayer element by displacing the punch toward the bottom wall of the cavity; and moving at least one lateral slider of the die portion defining the molding cavity toward the punch.

[0029] Advantageously, the step of moving the lateral slider is performed to compress the multilayer elements between the slider itself and the punch and to define a narrowing of the width of the forming cavity, which is measured along a line perpendicular to the longitudinal axis of the punch.

[0030] Preferably, multiple lateral sliders facing each other move toward the punch.

[0031] This compression step allows layers that did not adhere in the aforementioned bonding step to adhere perfectly.

[0032] Before the step of moving at least one lateral slider toward the punch, the step of compressing the multilayer element by displacing the punch is performed.

[0033] Advantageously, the lateral slider narrows the width of the forming chamber in a controlled manner and simultaneously with the compression action of the punch, so as not to overstretch the multilayer element along the punch's forward movement line. Attached Figure Description

[0034] The invention can be better understood and practiced with reference to the accompanying drawings, which illustrate several exemplary and non-limiting embodiments of the invention, in which: - Figures 1 to 3The sequence of methods for compression molding of multilayer components is illustrated schematically; - Figures 4 to 6 A second embodiment of the sequence of methods for compression molding of multilayer elements is schematically shown; - Figure 7 and Figure 8 The diagram schematically illustrates two different types of multilayer elements in the corresponding initial steps of compression molding; and - Figures 9 to 12 Different embodiments of multilayer elements for compression molding are illustrated schematically, all of which are within the scope of this invention. Detailed Implementation

[0035] refer to Figures 9 to 12 The image shown is a multilayer element 1 for compression molding according to the present invention and according to different embodiments.

[0036] Specifically, the multilayer element 1 includes a non-extruded material 2 that is at least 80% solid and at least one barrier layer 3 that can block liquids and / or oxygen.

[0037] In particular, the non-extruded material 2 is a natural fiber-based material, preferably, but not limiting, a cellulose-based material.

[0038] Advantageously, material 2 is a web of airflow web material, the thickness of which is greater than the thickness of barrier layer 3.

[0039] Alternatively, material 2 may be in the form of a dose obtained from pre-compacted powdered cellulose.

[0040] In addition, material 2 may have a constant cross-section and density, or there may be specific regions with variable thickness and / or density, depending on the products that need to be formed by compression molding and their intended use.

[0041] By way of example, the accompanying drawings schematically illustrate a multilayer element 1, wherein material 2 has a constant cross-section.

[0042] Advantageously, such as Figure 9 , Figure 11 and Figure 12 As shown, the barrier layer 3 is positioned on at least one outer surface of the non-extruded material 2.

[0043] In this case, the barrier layer 3 is typically hydrophobic to protect the cellulose material 2 from contact with water and moisture.

[0044] For this purpose, such as Figure 12 As specifically shown, the barrier layer 3 can be advantageously positioned on two opposing outer surfaces of the non-extruded material 2.

[0045] according to Figure 10 In another embodiment shown, the barrier layer 3 is positioned inside the non-extruded material 2.

[0046] The barrier layer 3 can be in the form of a film combined with the non-extruded material 2, or the barrier layer can be in the form of a liquid that is directly sprayed or coated onto the non-extruded material 2.

[0047] For example, the barrier layer 3 may include EVOH, PVOH, PA, or a fibrous material (e.g., nanocellulose) or a thin metal layer.

[0048] Layer 3, delivered in liquid form, is cured before and / or after and / or during compression molding.

[0049] However, it should be noted that the barrier layer 3 can have any properties and composition, depending on the specific function of the product obtained by compression molding the multilayer element 1.

[0050] Furthermore, the multilayer element 1 may also include a cover layer 4 bonded to the barrier layer 3. In this case, as... Figure 11 and Figure 12 As shown, the barrier layer 3 is located between the non-extruded material 2 and the cover layer 4.

[0051] Preferably, the covering layer 4 is made in the form of a natural fiber base film.

[0052] Advantageously, the covering layer 4 is a very thin paper, which is suitable for covering one or both outer surfaces of the multilayer element 1.

[0053] As explained above, the multilayer element 1 is suitable for manufacturing products by compression molding.

[0054] This method includes preparing according to the above-mentioned and in Figures 9 to 12 The initial steps of the multilayer element 1 described above in various embodiments shown in the figure.

[0055] The multilayer element 1 is then housed in the mold 100, located between the die portion 101 defining the forming cavity 102 and the punch 103 movable along the first longitudinal axis "X".

[0056] The steps of preparing the multilayer element 1 include conveying a continuous web made of non-extruded material 2 and bonding the continuous web to a barrier layer 3 that can block liquids and / or oxygen.

[0057] In the first embodiment, the barrier layer 3 is bonded to the non-extruded material mesh 2 by positioning the barrier film on at least one corresponding outer surface of the mesh itself.

[0058] This step can also be performed on a single surface of the non-extruded material 2 or on two opposing surfaces, such as... Figure 12 As shown.

[0059] This bonding can be achieved using known methods, such as compression and / or by using adhesive substances.

[0060] Alternatively, according to Figure 10 In one embodiment, the step of incorporating the barrier layer 3 into the non-extruded material mesh 2 can be performed by positioning the barrier film inside the mesh. In this embodiment, the barrier layer 3 is "embedded" in the non-extruded material 2.

[0061] Furthermore, in this case, the membrane of the barrier layer 3 can be located between two non-extruded material meshes 2.

[0062] Alternatively, the non-extruded material web 2 can be formed by compacting loose material (e.g., powdered cellulose). In this case, compaction is performed around the barrier layer 3 to embed the layer 3 itself within the non-extruded material 2.

[0063] According to another embodiment, the barrier layer 3 can be sprayed or coated in a substantially liquid form on at least one outer surface of the non-extruded material mesh 2.

[0064] Similarly, in this case, the step can be performed on a single surface of the non-extruded material 2 or on two opposing surfaces, such as... Figure 12 As shown.

[0065] according to Figure 11 and Figure 12 In one embodiment, after the step of bonding the barrier layer 3 to the non-extruded material mesh 2, the method may further include the step of bonding at least one cover layer 4 to the barrier layer 3.

[0066] In the same case, the step of combining the covering layer 4 can be carried out by known compression techniques and / or by using adhesive substances.

[0067] In addition, such as Figure 12 As shown, there may be two covering layers 4, which are positioned on opposite outer surfaces of the non-extruded material mesh 2.

[0068] Advantageously, the covering layer 4 can be in the form of a very thin paper, which is continuously disposed on the barrier layer 3 during the conveying of the non-extruded material web 2.

[0069] Advantageously, material 2 can be transported in the form of individual pieces, and each layer can be transported separately in the form of trays and stacked on material 2.

[0070] According to a first embodiment of the present invention, the multilayer element 1 formed in this manner is housed in the mold 100 in the form of a sheet.

[0071] In this case, the multilayer element 1 is cut from the multilayer continuous network into individual doses, the shape and size of which are suitable for forming the corresponding product "P".

[0072] Alternatively, the multilayer element 1 is housed in the mold 100 in the form of a continuous web. In this case, the multilayer continuous web can be compressed and molded using a set of molds 100 to obtain multiple products "P" simultaneously.

[0073] The method according to the invention also includes the step of compressing the multilayer element 1 by displacing the punch 103 toward the bottom wall 102a of the cavity 102.

[0074] It should be noted that the outer surface of the punch 103 and the inner surface of the cavity 102 define the shape of the product "P" to be manufactured by compression. The accompanying drawings schematically illustrate a cup-shaped product "P," i.e., a product obtained through a particularly deep punching action, by way of example. This product "P" can be, for example, a bottle cap or a coffee capsule.

[0075] However, the various parts of mold 100 can have any shape, depending on the production requirements of product "P".

[0076] After the compression step, a step is performed to move at least one lateral slider 104 of the die portion 101 defining the forming cavity 102 toward the punch 103.

[0077] This step is performed to compress the multilayer element 1 between the slider 104 itself and the punch 103.

[0078] Advantageously, there are multiple lateral sliders 104 that are opposite to each other and define the sidewalls 104a of the molding cavity 102.

[0079] More specifically, the movable lateral slider 104 defines at least the main lateral portion of the molding cavity 102. In other words, the lateral slider 104 forms the main lateral extension dimension of the cavity 102, which refers to more than half of the lateral extension dimension when measured along the longitudinal axis "X".

[0080] In this context, the bottom wall 102a may have a recess forming a "step" (not shown in the figures) that constitutes the lower end of the side wall 104a. In this case, this end of the side wall 104a is fixed because it is defined by the bottom wall 102a. Nevertheless, it should be noted that when measured along the axis "X", the extension length of this end of the side wall defined in the bottom wall 102a is significantly less than the extension length of the side wall 104a formed by the movable slider 104.

[0081] The slider 104 can move toward the punch 103.

[0082] It should be noted that the movement of the slider 104 toward the punch 103 defines a narrowing of the width of the forming cavity 102, which is measured along a line perpendicular to the aforementioned longitudinal axis "X" of the punch 103.

[0083] Additional sliders may also be present, which are telescopic relative to the punch and conveyed toward the cavity. These telescopic sliders, in conjunction with the movement of the lateral slider 104, facilitate molding and prevent one or more layers from cracking (tearing).

[0084] As explained above, before starting the step of moving the lateral slider 104, the punch 103 begins to move toward the bottom wall 102a.

[0085] Advantageously, when the punch 103 has begun to compress the multilayer element 1 into the cavity 102 but has not yet completed the compression ( Figure 2 The movement of slider 104 begins. In other words, the movement of lateral slider 104 occurs during the movement of the punch toward the bottom wall 102a.

[0086] In this case, the final compression motion of the punch 103 and the side slider 104 occurs essentially in a coordinated manner so as to shape the element 1 by simultaneously compressing the entire surface of the multilayer element 1 itself.

[0087] In this way, instead of being stretched toward the bottom wall 102a, element 1 is instead "received" inside a cavity that gradually narrows to compress both the bottom wall 102a region and the side surface 104a region at the same time.

[0088] In this regard, it should be noted that most of the extension length of the cavity 102 along the axis "X" is defined by the movable slider 104. Therefore, any recesses formed in the bottom wall 102a (which thereby define the lateral section of the fixed end) do not affect the tensile force on the fibers constituting the multilayer element.

[0089] In this case, the stretching effect is instead controlled by the movement of movable sliders 104 that house element 1 within the cavity.

[0090] This movement maintains the structure of the materials constituting the multilayer element 1, and in particular, maintains the structure of the thin film defining the barrier layer 3 and the cover layer 4.

[0091] refer to Figures 4 to 6 In some embodiments, the method may further include the step of locking the peripheral edge of the multilayer element 1 before moving the punch 103 along the line “X”.

[0092] This step is performed by moving the clamping body 105, which is positioned around the punch 103, toward the contact plane 101a of the die portion 101, which is positioned around the forming chamber 102.

[0093] It should be noted that the contact plane 101a is formed on the upper surface of each lateral slider 104, which is supported on each lateral slider in the corresponding initial step of the multilayer element 1 being housed on the press 100.

[0094] Therefore, the clamping body 105 moves toward the contact plane 101a to engage with the peripheral edge of the multilayer element 1 and is held in place by the punch 103 and the respective lateral sliders 104. Figure 5 and Figure 6 The perimeter edge is maintained during the compression step.

[0095] Advantageously, the multilayer elements are held in place during the respective molding steps to fix the respective peripheral edges at a predetermined distance from the bottom wall 102a.

[0096] It should be noted that, Figures 1 to 6 This demonstrates the process of forming a multi-layer element 1 by compression molding, wherein a barrier layer 3 is housed within a non-extruded material 2. Figure 10 ).

[0097] However, as already explained, the above method is applicable to any type of multilayer element 1 described above. For example, Figure 7 and Figure 8 A mold 100 is shown in the initial step of molding a multi-layer element 1, which has a barrier layer 3 and a cover layer 4 respectively on one surface and two opposite surfaces of an incompressible material 2.

[0098] This invention solves the problems encountered in the prior art and brings important advantages.

[0099] First, the multilayer element 1 is fully compostable and / or recyclable, and simultaneously provides an oxygen and water barrier. Therefore, element 1 can be used to manufacture a highly versatile product "P".

[0100] In addition, a barrier layer 3 in the form of a very thin membrane can be used, thereby ensuring the barrier function without affecting the biodegradable characteristics of the entire element 1.

[0101] This advantage stems from the method according to the invention, which does not stretch the fibers during the corresponding compression molding steps.

[0102] In fact, the punch 103 and the side slider 104 work together to compress the element 1 simultaneously along two vertical lines.

[0103] Therefore, when the central region of element 1 is compressed between the punch 103 and the bottom wall 102a, the peripheral region of element 1 is gradually compressed towards the punch by the lateral slider 104. This action gradually shapes element 1 without stretching the material of element 1 itself, thereby avoiding breakage and excessive elongation of the barrier layer 3.

[0104] Advantageously, element 1 with a limited material layer thickness can be used, thus offering advantages in terms of the amount of material used and therefore production costs.

[0105] It should also be noted that element 1 is not overheated (but heating can be provided at a very low temperature compared to the extrusion method in any case), which in any case allows the integrity of the material to be maintained during compression to facilitate the molding of product “P”.

[0106] Advantageously, a very deep product “P” can be obtained without affecting the structural integrity of the materials constituting the multilayer element 1.

Claims

1. A multilayer element (1) for manufacturing articles by compression molding, wherein, The multilayer element comprises at least 80% of a non-extruded material (2) in solid phase and includes at least one barrier layer (2) capable of blocking liquids and / or oxygen, wherein the non-extruded material (2) is a web or segment of an airflow mesh material and the thickness of the non-extruded material is greater than the thickness of the barrier layer (3).

2. The multilayer element according to the preceding claim, wherein, The non-extruded material (2) is a natural fiber-based material.

3. The multilayer element according to any one of the preceding claims, wherein, The non-extruded material (2) is a cellulose-based material.

4. The multilayer element according to any one of the preceding claims, wherein, The barrier layer (3) is positioned on at least one outer surface of the non-extruded material (2).

5. The multilayer element according to any one of the preceding claims, wherein, The barrier layer (3) is positioned on two opposite outer surfaces of the non-extruded material (2).

6. The multilayer element according to any one of claims 1 to 3, wherein, The barrier layer (3) is positioned inside the non-extruded material (2).

7. The multilayer element according to any one of the preceding claims, wherein, The barrier layer (3) is in the form of a film combined with the non-extruded material (2).

8. The multilayer element according to any one of claims 1 to 6, wherein, The barrier layer (3) is sprayed or coated onto the non-extruded material (2) in liquid form.

9. The multilayer element according to claim 4 or 5, wherein, The multilayer element further includes a cover layer (4) bonded to the barrier layer (3); the barrier layer (3) is located between the non-extruded material (2) and the cover layer (4).

10. The multilayer element according to the preceding claim, wherein, The covering layer (4) is made in the form of a natural fiber base film.

11. A method for manufacturing a product (P), wherein, The method includes the following steps: -Preparation of a multilayer element (1) according to any one of claims 1 to 11; - The multilayer element (1) is housed in a mold (100) such that the multilayer element is located between the die portion (101) defining the forming cavity (102) and the punch (103) movable along the first longitudinal axis (X); - By displacing the punch (103) and the cavity (102a) relative to each other, so that the punch (103) moves itself toward the bottom wall (102a) of the cavity (102), the multilayer element (1) is compressed; and - Move at least one lateral slider (104) of the die portion (101) toward the punch (103), wherein at least one of the lateral sliders defines at least a major lateral portion of the forming cavity (102); - Perform the step of moving the lateral slider (104) to compress the multilayer element (1) between the slider (104) itself and the punch (103).

12. The method according to the preceding claim, wherein, The step of moving at least one of the lateral sliders (104) defines a narrowing of the width of the forming cavity (102), which is measured along a line perpendicular to the longitudinal axis (X) of the punch (103).

13. The method according to claim 11 or 12, wherein, The step of moving at least one of the side sliders (104) is performed by moving the plurality of the side sliders (104) that are opposite to each other toward the punch (103).

14. The method according to any one of claims 11 to 13, wherein, Before the step of moving at least one of the lateral sliders (104) toward the punch (103), the step of compressing the multilayer element (1) by displacing the punch (103) is performed.

15. The method according to the preceding claim, wherein, During the movement of the punch (103) toward the bottom wall (102a), the step of moving at least one of the lateral sliders (104) toward the punch (103) is performed.

16. The method according to any one of claims 11 to 15, wherein, The method further includes locking the peripheral edge of the multilayer element (1) before the step of compressing the multilayer element (1) by displacing the punch (103) toward the bottom wall (102a).

17. The method according to the preceding claim, wherein, The step of locking the peripheral edge is performed by moving the clamping body (105) positioned around the punch (103) toward the contact plane (101a) of the die portion (101) positioned around the forming chamber (102); the peripheral edge of the multilayer element (1) is held during the forming step performed by the punch (103) and the lateral slider (104).

18. The method according to any one of claims 11 to 17, wherein, The multilayer element (1) is housed in the mold in the form of a sheet.

19. The method according to any one of claims 11 to 17, wherein, The multilayer element (1) is housed in the mold in the form of a continuous mesh.

20. The method according to claim 18 or 19, wherein, The step of preparing the multilayer element (1) includes, prior to the step of accommodating the multilayer element (1) in the mold (100), conveying a continuous web made of the non-extruded material (2) and combining the continuous web with the barrier layer (3) that can block liquids and / or oxygen.

21. The method according to the preceding claim, wherein, The step of combining the barrier layer (3) with the non-extruded material mesh (2) is performed by positioning a barrier film on at least one corresponding outer surface of the mesh.

22. The method according to claim 20, wherein, The step of combining the barrier layer (3) with the non-extruded material mesh (2) is performed by positioning a barrier film inside the mesh.

23. The method of claim 20, wherein, The step of combining the barrier layer (3) with the non-extruded material mesh (2) is performed by spraying or coating a substantially liquid barrier onto at least one outer surface of the mesh.

24. The method of claim 20, wherein, The step of preparing the multilayer element (1) further includes, after the step of combining the barrier layer (3) with the continuous mesh, the step of combining at least one cover layer (4) onto the barrier layer.

25. The method according to any one of claims 11 to 24, wherein, The lateral slider (104) defines the lateral extension dimension of the cavity (102) measured along the longitudinal axis (X), which is greater than half of the extension dimension of the cavity (102) itself measured along the axis (X).

Images