Method and device for producing honeycomb cores from recycled plastic

Abstract

The invention relates to a method and device for producing cores for honeycomb panels, the core being produced in a linear and continuous manner. The device comprises an injector designed for recycled plastic, a loading hopper, an induction coil for increasing the temperature and melting the recycled plastic, a main mould body and a secondary moveable honeycomb-shaped mould body. The method comprises five steps, wherein the recycled plastic is injected into the main and secondary moulds and, once it adopts the honeycomb form, the secondary mould is moved linearly to form a continuous linear panel.

Description

[0001] PROCESS AND EQUIPMENT FOR MANUFACTURING HONEYCOMB CORES FROM RECYCLED PLASTIC

[0002] DESCRIPTIVE MEMORY

[0003] PRIOR ART

[0004] The use of recycled plastic for the manufacture of multiple materials is becoming increasingly widespread, and the creation of panels with a panel-like or honeycomb structure is no exception. The use of honeycomb panels offers significant advantages for manufacturing lighter, more mechanically resistant parts for furniture, boxes, lightweight ceilings, and other applications. Typically, honeycomb panels are made of two thin panels, firmly bonded by a thick layer of honeycomb core on both sides of the panel, also known as a honeycomb sandwich structure. Furthermore, the honeycomb board also refers to a large number of shear waveguides welded together, forming a shear waveguide array, a Honey Comb Board, to create a large aperture area, but also to prevent electromagnetic leakage from the panel.

[0005] Honeycomb panels are divided into cushioning honeycomb panels and packaging honeycomb panels. Due to their special structure, they can improve compressive strength.

[0006] Document CN105835484 describes a manufacturing process of a hexagonal honeycomb that includes a plurality of hexagonal honeycomb units and plastic films arranged on the upper and lower surfaces of the honeycomb units, each honeycomb unit has six side walls, two side walls in the vertical direction between the honeycomb units are not connected, and the remaining four side walls are the common side walls of two neighboring units. According to the hexagonal honeycomb, plastic films are fused on the upper surface and the lower surface of the hexagon, the upper surface and the lower surface of the hexagon are all sealed, thereby overcoming the problem of linear contact between a round tube honeycomb surface, layer (various sheets) and a central layer of honeycomb, achieving surface contact and greatly improving strength.The two vertical sidewalls between the honeycomb units are not connected, allowing for a certain amount of space, thus providing a honeycomb slab with superior sound and heat insulation benefits. The honeycomb does not contain glue or other harmful solvents and can achieve 100% recovery.

[0007] Document CN102700144 teaches a production process and equipment for forming a cellular board by continuous vacuum extrusion, belonging to the field of plastic forming. The equipment continuously extrudes a thermoplastic material through an extrusion head to form a hexagonal cellular structure layer in a continuous vacuum plastic absorption manner; and in the continuous forming process, with the adoption of production technology and process, a sheet material is combined on an upper surface, a lower surface, or a single surface of the cellular structure layer in line. Document US2008176027 describes a semi-closed thermoplastic folded honeycomb structure produced from a continuous network of material by plastic deformation perpendicular to the plane of the material to thereby form semi-hexagonal cell walls and small connecting areas.When folded in the transport direction, the cell walls join together to form the alveolar structure.

[0008] Document CN102717508 describes a process for producing plastic foam board comprising the following steps: extruding plastic sheets in a movable beveled mold in a forming device or sending formed plastic sheets to the movable mold after heating the formed plastic sheets; adsorbing the sheets on the movable mold by vacuum adsorption to form a foam board product with the same shape as the mold; cooling the product; and carrying out a collection treatment of fixed-length cutting, stress relieving, and forming on cooled products in sequence.The equipment for producing the plastic cellular panels comprises a first sheet extrusion machine, in which a forming device is arranged below the head of the sheet extrusion machine; a cooling device, a pulling device, a stress relief device, a shaping device and a device for collecting fixed-length blanks are arranged in sequence on the forming device. US2020094460 describes a process for producing components or profiles from at least one solid if!cable plastic mass in an injection molding installation, said process comprising stationary mold components and mold components that are movable relative to them. The process includes injecting solidifiable plastic mass into a channel formed in the movable mold components and, from there, by means of portioned connections into one or more mold cavities.The channel is surrounded by at least one stationary, temperature-controlled mold component. The fixing dough bars form a continuous dough bar, which is transported out of the casting site with increasing cooling and solidification and increasing length, along with the filled mold cavities and portions of mold cavities. The rolling dough bar, together with the connecting dough bars, after solidification and after opening the mold cavity or cavities, is separated from the component or components, and the component or components are ejected.

[0009] Unlike prior art documents, the equipment and process of the invention provide a specific solution for the linear production of honeycomb cores using recycled plastic on an industrial scale, through the production of linear and continuous honeycomb panels. This not only solves the current problem of industrial viability but also contributes to the sustainable use of recycled plastic in the manufacture of these panels. The invention comprises an iterative process consisting of five steps, all of which must be completed to restart the cycle. This process, combined with the developed machinery, allows for the manufacture of double rows of standard dimensions common in the construction materials market, all tailored to the specific requirements of each client. Since the process is continuous, in theory we could consider the production of a panel of infinite length.In addition, you can choose different configurations of the hexagons that make up the honeycomb: width, height, diameter, or thickness.

[0010] BRIEF DESCRIPTION OF THE FIGURES

[0011] Figure 1: corresponds to an isometric view of the equipment for forming panels with a honeycomb core of the invention.

[0012] Figure 2: corresponds to a front view of the equipment for forming panels with a honeycomb core of the invention.

[0013] Figure 3: corresponds to a top plan view of the equipment for forming panels with a honeycomb core of the invention.

[0014] Figure 4: corresponds to an isometric view from above of the equipment for forming panels with a honeycomb core of the invention.

[0015] Figure 5: corresponds to a front view of the equipment that illustrates the first stage of the process in which the secondary body of the mold starts from the lower initial position.

[0016] Figure 6: corresponds to a side view of the equipment that illustrates the first stage of the process in which the secondary body of the mold starts from the lower initial position. Figure 7: corresponds to a top view of the equipment that illustrates the first stage of the process in which the secondary body of the mold starts from the lower initial position.

[0017] Figure 8: corresponds to a front view that illustrates the closed mold bodies in the plastic injection process in the second stage of the manufacturing process of the invention.

[0018] Figure 9: corresponds to a lower isometric view that illustrates the closed mold bodies in the plastic injection process in the second stage of the manufacturing process of the invention.

[0019] Figure 10: corresponds to a top isometric view that illustrates the closed mold bodies in the plastic injection process in the second stage of the manufacturing process of the invention.

[0020] Figure 11: corresponds to a lateral isometric view that illustrates stage 3 of the process in which the mobile secondary body moves forward as indicated by the arrow.

[0021] Figure 12: corresponds to a side view that illustrates stage 3, the process in which the mobile secondary body moves forward.

[0022] Figure 13: corresponds to a side view of stage 4 of the process in which the secondary body of the mold descends (A) and then in stage 5 moves back (B) to the original position and restarts the continuous injection process.

[0023] Figure 14: corresponds to an isometric view of stage 4 of the process in which the secondary body of the mold descends. DESCRIPTION OF THE INVENTION

[0024] For the sake of order and understanding of the invention, the equipment will be described first, followed by the process for the continuous production of panels with a linear honeycomb core.

[0025] The equipment of the invention is made up of a set of injectors, hoppers, molds and induction heaters.

[0026] The equipment comprises at least one electric motor that powers a screw conveyor, which is used to inject recycled plastic. The body housing the screw conveyor is located directly below the electric motor that rotates it. The screw conveyor is coupled to a pipe that forms part of a plastic material loading hopper, such that the plastic material descends from the hopper to the screw conveyor through the pipe, comes into contact with the latter, and is displaced downstream.

[0027] The auger body includes an induction system along its outer perimeter, consisting of an induction coil, which acts as a plastic heater and is moved by the auger. The induction coil allows the plastic to be heated to a molten state, i.e., to the state when the plastic changes from a solid to a liquid state.

[0028] Beneath the body of the auger is a structure comprising a fixed primary mold composed of multiple hexagonal grooves, typical of the honeycomb shape. Immediately below the fixed primary mold is a movable secondary mold, composed of multiple solid bodies with a hexagonal cross-section matching the hexagonal grooves of the fixed primary mold. Both molds, when in operation—that is, when the movable secondary mold moves and inserts itself into the fixed primary mold—form the body of the mechanical mold into which the molten plastic is injected from the auger body.

[0029] The equipment includes a system for advancing the panel formed by injecting plastic into the mechanical mold body. The entire operation will be explained in the process of the invention.

[0030] The equipment also includes an electrical system for powering at least one electric motor, the induction system, and the panel advance system. It also includes an injection command, which controls the rotation of the worm screw, the movement of the secondary body, and the temperature of the injection system. For this purpose, the equipment includes a microcontroller programmed specifically for this purpose. All parameters are adjustable.

[0031] The method for manufacturing linear, continuous honeycomb panels involves an iterative process consisting of five stages, each of which must be completed to restart the cycle. This process, which is carried out on the equipment described above, allows for the production of double rows of standard dimensions common in the construction materials market, for example, 1.22 m wide, although this can be adjusted upon request. The process is continuous and comprises the following stages:

[0032] In the first stage, the movable secondary mold starts from a lower initial position, below the fixed primary mold. In this sequence, the movable secondary mold is inserted into the fixed primary mold, thereby closing the assembly that forms the body of the mechanical mold.

[0033] In a second stage, the primary and secondary molds are positioned to inject the previously molten material, using the injection system and heating via the induction system. This stage uses the face of the panel generated in the previous iteration as the front face of the mold. This idea of ​​using the same panel as part of the mold allows for the partial casting of the material that will be joined to the newly molten material.

[0034] The critical part of this process is the joining of the first pair of dies with the subsequent ones. This step is carried out starting with the second iteration of the process, when the second injection of plastic is made, which adheres to the back layer of the second column in a partial casting process.

[0035] In the third stage, the movable secondary mold moves forward. The displacement is two rows, and it is now possible to observe the hexagons formed in the movable secondary mold. Stage 4 involves the movable secondary mold descending from the fixed primary mold once the plastic material has been injected. Once it has descended, stage 5 involves the secondary mold returning to its original position to begin a new iteration in the continuous injection process of the invention. As multiple iterations are executed, the resulting panel increases in length, which strictly speaking can be infinite, although the iteration is obviously performed until the desired panel length is reached.

[0036] DETAIL DESCRIPTION OF THE REFERRED DPR MODALITY

[0037] A device for manufacturing linear and continuous honeycomb structure panels is described, comprising at least one electric motor (1) connected to a body (7) which comprises an endless screw inside which the recycled plastic material flows when it is melted. The body (7) is connected just below the at least one electric motor (1) that provides the driving force that makes the endless screw rotate. The body (7) of the endless screw is coupled to a pipe (8) that forms part of a loading hopper (2) of plastic material, in this case recycled plastic, such that the plastic material descends from the loading hopper (2) to the body (7) of the endless screw through the pipe (8), comes into contact with the latter and is displaced downstream.

[0038] The body (7) of the auger comprises on its outer perimeter an induction system composed of an induction coil (3), by means of which the plastic fed by the auger is heated. The induction coil (3) provides the melting temperature of the recycled plastic to melt it.

[0039] Beneath the body (7) of the auger screw is a structure comprising a fixed primary main mould (4) composed of multiple hexagonal grooves. Immediately below the fixed primary mould (4) is arranged a mobile secondary mould (5), which is composed of multiple solid bodies having a hexagonal cross section coinciding with the hexagonal grooves of the fixed primary mould (4). In operation, the fixed primary mould (4) and the mobile secondary mould (5) are joined so as to form a gap between them. Both moulds joined together constitute the body of the mechanical mould into which the molten plastic is injected from the body of the auger screw.

[0040] The equipment includes a panel advance system (6) that is formed by injecting plastic into the mechanical mold body.

[0041] The equipment also comprises an electrical system to feed each electric motor (1), the induction system and the panel advance system (6). It also comprises an injection command, which controls the rotation of the endless screw, the movement of the mobile secondary mold (5) and the temperature of the induction system, for which the equipment comprises a microcontroller programmed for such case. All parameters are adjustable. The method for manufacturing panels with a honeycomb structure that are linear and continuous, comprises an iterative process consisting of five stages, which must be completed to restart the cycle. Through this process, which is executed in the equipment described above, double dies of standard dimensions common in the construction materials market are manufactured. The process is continuous, and comprises the following stages:

[0042] In a first stage, the mobile secondary mold (5) starts from a lower initial position (14), below the fixed primary mold (4). The mobile secondary mold (5) moves, inserting itself (15) into the fixed primary mold (4), closing the assembly that forms the body of the mechanical mold.

[0043] A second stage comprises injecting (9) molten plastic into the gap of the mechanical mould body, formed by the fixed primary mould (4) and the mobile secondary mould (5), through the injection system and the plastic heated by the induction coil (3). This stage comprises that the face of the panel (6) generated in a previous iteration acts as the front face of the mould body. That is, the back face of the panel (6) is partially melted in order to join new material that is injected to continue the production of the panel (6). The fact of using the same panel (6) as part of the mould body, allows the part of the material that is going to be joined to the new molten material to be partially melted.

[0044] The critical part of this process is the joining of the first pair of columns with the following ones. This step is carried out starting with the second iteration of the process, when the second injection of plastic is made, which adheres to the back layer of the second column in a partial casting process.

[0045] A third stage comprises the mobile secondary mould (5) moving forward (11) with respect to the fixed primary mould (4) in the direction where the panel (6) is being formed. The movement is two rows (12), and the hexagons (10) are formed in the body of the mechanical mould.

[0046] Step 4 comprises that the movable secondary mold (13) descends from the fixed primary mold (4) once the plastic material has been injected. Once it has descended, step 5 comprises that the secondary mold returns to the original position (14) to begin a new iteration in the continuous injection process of the invention. As multiple iterations are executed, the resulting panel (6) increases in length, which strictly speaking can be infinite, although obviously the iteration is carried out until the desired panel length is reached.

Claims

MODIFIED CLAIMS received by the International Bureau on 26 May 2025 (26.05.2025) 1. Equipment for the linear production of panels with honeycomb cores using recycled plastic on an industrial scale, through the production of linear and continuous honeycomb panels, useful in construction, CHARACTERIZED in that it comprises at least one electric motor (1) connected to a body (7) that inside comprises a worm screw, said body (7) being connected just below the at least one electric motor (1) that provides the driving force that makes the worm screw rotate; wherein the body (7) of the worm screw is coupled to a pipe (8) that forms part of a loading hopper (2) made of plastic material; wherein the body (7) of the worm screw comprises on its outer perimeter an induction system composed of an induction coil (3);in which under said body (7) of the auger screw there is arranged a structure comprising a fixed primary main mould (4) composed of multiple hexagonal grooves and immediately below the fixed primary mould (4) there is arranged a mobile secondary mould (5); which comprises a system for advancing the panel (6) that is formed as a result of the injection of plastic into the mechanical mould body, and which together form a gap between them and constitute a body of the mechanical mould into which the molten plastic is injected from the body (7) of the auger screw.

2. Equipment for the linear production of panels with honeycomb cores according to claim 1, CHARACTERIZED in that said mobile secondary mold (5) composed of multiple solid bodies that have a hexagonal cross section coinciding with the hexagonal grooves of said fixed primary mold (4).

3. Equipment for the linear production of panels with honeycomb cores according to claim 1, CHARACTERIZED in that it also comprises an electrical system to feed each electric motor (1), the induction system and the panel advance system (6).

4. Equipment for the linear production of panels with honeycomb cores according to claim 1, CHARACTERIZED in that it also comprises an injection command, which controls the rotation of the auger, the movement of the mobile secondary mold (5) and the temperature of the induction system.

5. Equipment for the linear production of panels with honeycomb cores according to claim 4, CHARACTERIZED in that it also comprises a microcontroller programmed to control the injection command, the movement of the mobile secondary mold (5) and the temperature of the induction system.

6. Process for the linear production of panels with honeycomb cores using recycled plastic on an industrial scale, through the production of linear and continuous honeycomb panels, useful in construction, CHARACTERIZED because it comprises an iterative process comprising the following stages: a. inserting a movable secondary mold (5) from an initial position (14) from below into a fixed primary mold (4), closing and forming an assembly that forms a mechanical mold body, wherein said mechanical mold body comprises a gap; b. comprises injecting (9) molten plastic into the gap of the mechanical mold body, formed by the fixed primary mold (4) and movable secondary mold (5), through an injection system and the plastic heated by an induction coil (3); c. moving the movable secondary mold (5) forward (11) with respect to the fixed primary mold (4) in the direction where a panel (6) is being formed; d. lowering (13) the movable secondary mold (5) from the fixed primary mold (4) once the plastic material has been injected; and e. moving the secondary mold (5) to the original position (14) to start a new iteration; where the injection step comprises that the face of a panel (6) generated in a previous iteration, acts as the front face of said mold body; and where the process also includes the step of: partially melt the back face of said panel (6) in order to join new material that is injected into the body of the mold to continue the production of the panel (6).

7. Process for the linear production of panels with honeycomb cores according to claim 6, CHARACTERIZED in that said displacement of step c) is two rows (12), and the hexagons (10) are formed in the body of the mechanical mold.

8. Process for the linear production of panels with honeycomb cores according to claim 6, CHARACTERIZED in that it comprises multiple iterations in which the panel (6) increases in length.

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