Method of making fiber-based product from pulp

Abstract

A method for manufacturing a fiber-based product, in particular a container or a fiber-based closure element for a container, from pulp is disclosed. The method comprises the following steps: providing a casting mold; introducing pulp into the casting mould such that a wet fibre-based preform (60) is formed; -drying the wet fibre-based preform; -dimensionally cutting the dried preform (61) by cutting off the excess length (62).

Description

Technical Field

[0001] According to the preambles of the independent claims, the invention relates to a method for producing a fiber-based product, in particular a container or a fiber-based closure element for a container, from pulp. Background Art

[0002] A fiber-based container is proposed in WO 2012 / 139590 A1. To produce such a container, a so-called pulp is sprayed into an inverted mold and pressed against corresponding walls in the mold using a flexible balloon and compressed accordingly. The pulp is compressed and heated to a temperature of about 180° C. in order to dry the container.

[0003] Pulp is a mixture of fibers and water, in particular natural fibers, such as hemp, cellulose or flax or mixtures thereof. Optionally, the pulp has additives, for example to improve the solidification of the compressed pulp, or to have an effect on the subsequent appearance, or generally to change the properties of the pulp or the subsequent container.

[0004] Because the pulp consists of different components with variable properties, the spraying process is also very difficult to control. In particular, the type and amount of pulp deposited in the mold is largely accidental. This is reflected in different properties of the finished container, for example, different wall thicknesses and therefore different strengths or different surfaces, and in particular different dimensions of the same element of different containers.

[0005] Since the containers are formed in a negative mold, very high dimensional accuracy can be achieved with respect to the outer contour of these containers. Depending on the specific properties of the pulp from which the container is formed, the inner contour or inner surface of the container may exhibit deviations of different sizes. These deviations are generally negligible, with the exception of deviations in the region of the opening of the container on which the container closure is arranged or the container neck which is designed with corresponding fastening elements for the container closure. Due to the material properties of the pulp, the upper final edge of the opening is subject to greater tolerances and is generally fibrous.

[0006] This is particularly disadvantageous since this forms the joint, for example with a container closure, and this joint must be dimensionally accurate. Summary of the invention

[0007] The object of the present invention is to eliminate at least one or more disadvantages of the prior art. In particular, a method is provided which allows the manufacture of fiber-based containers with accurate dimensions, in particular as independent as possible of deviations of the container material. It is advantageous to be able to avoid any post-processing of the container.

[0008] This object is achieved by the method defined in the independent claim. Further advantageous embodiments result from the dependent claims.

[0009] The method according to the invention for producing a fiber-based product, in particular a container or a fiber-based closure element for a container, from pulp comprises the following steps:

[0010] - provide a casting mold,

[0011] - Introducing pulp into the mold so that a wet fiber-based preform is formed

[0012] - Drying the wet fiber-based preform

[0013] - Cut the dried preform to size by cutting off any excess length.

[0014] The sequence of these steps makes it possible to manufacture a product from the pulp material which can be produced repeatedly with exact dimensions. Cutting the dried preform ensures that each product has the same dimensional accuracy.

[0015] The product is preferably a container for liquids, in particular a beverage bottle.

[0016] To form a fiber-based preform, the pulp is introduced into a casting mold by means of the following steps:

[0017] - filling the casting mould with a process liquid, in particular water, so that a liquid reservoir is formed in the casting mould,

[0018] - Applying pulp to the liquid reservoir

[0019] - Replacing the liquid reservoir by draining it through the mold in a targeted manner.

[0020] Filling the casting mold with process liquid allows certain process conditions to be created within the casting mold.The liquid reservoir provides an upright column that is substantially free of turbulence and / or eddies.

[0021] By applying the pulp to the liquid reservoir, two media with comparable properties are brought into contact. For example, if water is used as process liquid, the liquid reservoir also consists of water. The pulp is also a mixture essentially based on water. Therefore, if the pulp is applied to the liquid reservoir, the two media do not mix. The liquid reservoir is actually replenished by the pulp. Therefore, the liquid reservoir provides a vertical water column, which is extended only by applying the pulp to this water column.

[0022] The casting mould for producing the fiber-based preform is usually liquid permeable and has two mold halves that can be separated from each other. The two mold halves provide a cavity into which the pulp is introduced. In a simple embodiment, the casting mould can be made, for example, of a metal grid having an outer boundary that is impermeable to liquid, so that a liquid reservoir can be provided within the casting mould. In a simple embodiment, the outer boundary can be provided, for example, by a container, which can be filled.

[0023] The cavity substantially corresponds to the negative mold of the preform to be manufactured and has a mouth opening like the preform. Accordingly, the pulp is introduced via the mouth opening. In a container shaped like a bottle, the mouth opening is a pouring opening at the neck of the bottle. However, the preform can also take the form of a container that is open at the top and has no specific opening, such as a bowl, a cup or a tray. These containers are provided with an opening, which usually points upward when used as intended. Accordingly, the pulp is introduced via the opening cross section corresponding to the opening. However, it can also be provided that the casting mold of such a wide-necked container, such as a cup, is closed with a cover in the area of ​​the opening and a separate mouth is provided here to introduce the pulp into the casting mold.

[0024] After the pulp has been applied to the liquid reservoir, the liquid reservoir can be replaced by draining it in a targeted manner through the casting mold.By draining the liquid reservoir, the pulp flows into the casting mold.

[0025] The discharge process can be controlled by an overpressure applied to the pulp. Additionally or alternatively, provision can be made to remove the liquid reservoir in the casting mold using a vacuum so that the pulp is sucked into the casting mold.

[0026] The liquid reservoir may also be drained in a stop-controlled manner, such that the draining rate is limited, or may be controlled using a closed loop control by limiting the draining volume, for example.

[0027] By draining the liquid reservoir, a flow of the pulp can take place, in particular within the casting mould, and the inflowing pulp can settle on the inner wall of the casting mould and thus on the cavity.

[0028] By depositing the pulp on the inner wall of the casting mould, the wall of the subsequent preform is formed.Controlling or adjusting the pressure or volume as described above can influence the settling process and thus the structure of the wall.

[0029] Additionally or alternatively, different pulps can be introduced successively into the casting mold. By such a sequential introduction of different pulps, a layered structure of the preform can be produced in the casting mold. For example, pulps can be used that differ in color or in their properties, in particular in their fiber properties or in their functional properties such as barrier properties.

[0030] It can be provided that the liquid reservoir is discharged from the casting mold at a plurality of points. These points can correspond to different sections or regions of the subsequent preform and thus also to the casting mold.

[0031] By draining the liquid reservoir at multiple points, the flow of pulp within the casting mould can be directed so that the settling of the pulp can also be controlled and regulated. This allows the walls of the preform to be specifically configured and the amount and location of the deposited or settled pulp to be controlled in a targeted manner using open loop control.

[0032] In this case, pulp settling refers to the settling of the fibers contained in the pulp, in this case in the cavity on the inner wall of the casting mold.

[0033] Provision can be made for the liquid reservoir to be drained from the casting mold via a plurality of points in a specific time sequence.

[0034] This allows a precise control of the pulp flow and thus a targeted distribution of the fibers.Thus, the structure of the preform wall can be controlled in a targeted manner and a fiber distribution within the preform wall can be produced which meets specific requirements.

[0035] For example, in the area that is subject to increased forces, a thicker structure can be achieved than in the rest of the preform. For example, a preform can be produced for a container that is optimized in terms of weight, stackability (top load), fiber orientation and more. By depositing the fibers in a targeted manner, it is possible to avoid increasing the deposition of fibers in places that are hardly subject to stress. This is not possible with conventional methods. The wall thickness of the preform and therefore the wall thickness of the container usually always corresponds to the wall thickness required to absorb the maximum forces, because the conventional methods used do not allow for targeted control of the fiber sedimentation process.

[0036] It can be provided that the corresponding casting mold has a plurality of discharge openings which are opened in a specific time sequence. In this case, the term "discharge" refers to removing liquid from the casting mold.

[0037] Preferably, the pulp is introduced into the casting mould under overpressure; in particular, the overpressure is generated after the pulp has been applied to the liquid reservoir, ie during draining of the liquid reservoir. The pressure can in particular be built up before draining of the liquid reservoir.

[0038] By building up an overpressure, the flow of the pulp can be controlled more precisely.

[0039] Prior to the introduction of the pulp, the casting mould can be backwashed by filling it with a process liquid. The process liquid can be discharged through an opening in the casting mould, which opening corresponds to the opening in the preform. This allows the casting mould to be easily backwashed, wherein the backwashing liquid and the process liquid are preferably the same. Once the backwashing process stops, the casting mould has been filled with a liquid reservoir as described herein, and pulp can be immediately applied to the liquid reservoir.

[0040] This simplifies the entire process. The fibers still in the backwashing liquid have no negative impact and can at most be directly reused in a subsequent step and deposited accordingly in the casting mold. Since no further process steps are required between backwashing and applying the pulp, the method is also relatively fast.

[0041] To dry the preform, at least the following steps may be performed:

[0042] - providing a fiber-based preform in a microwave permeable press mold,

[0043] - introducing an expandable tool into the fiber-based preform,

[0044] - expanding the expandable tool so that the fiber-based preform is compressed to reduce the water content of the fiber-based preform,

[0045] - Exposing the pressed preform to microwaves.

[0046] By providing the fiber-based preform in a microwave permeable press, the wet fiber-based preform can be kept inside the mold during the drying process, i.e. during exposure to microwaves. Thus, the container is protected from external influences and prevented from being damaged or deformed. By providing the wet fiber-based preform in a microwave permeable press, it is also ensured that the preform is accessible to microwaves from all sides and can therefore be dried from all sides. After this drying step, the wet fiber-based preform has a water content of about 5% to 12%.

[0047] In the process of the invention, a wet fiber-based preform is generally formed as described herein. In other words, the pulp is introduced into a porous mold or into a solid mold with drainage channels, the inlet of which is covered by a screen or the opening of which is small enough that the fibers of the pulp cannot penetrate, and the fibers of the pulp are applied to the inner wall of the mold to form the wall of the container. Once the wall is thick enough, the swelling of the pulp stops. The semi-finished product now present, i.e. the wet fiber-based preform, is removed from the mold and introduced into a microwave permeable press mold and thus provided in the press mold. At this point, the wet fiber-based preform has a water content of about 75% or less, so that it can be transported between processing stations in a dimensionally stable manner.

[0048] The wet fiber-based preform is removed from the casting mold using a suitable transfer device. Subsequently, the wet fiber-based preform is inserted into the opened compression mold. The compression mold is preferably formed of two parts. In this case, removal and insertion may require blowing out and / or suction by means of negative or positive pressure. It is also possible to use a purely mechanical gripper for this transfer.

[0049] Typically, the compression mold may have an inner wall that is designed to have a higher surface quality than the inner wall of the casting mold.

[0050] Preferably, the expandable tool is introduced into the fiber-based preform after the fiber-based preform has been provided in the compression mold. By expanding the expandable tool, the water content of the fiber-based preform can be reduced in a first step by compressing the walls of the preform. At this point, the wet fiber-based preform has a water content of about 50%-60%.

[0051] At the same time, a surface with improved properties can be produced on the wet fiber-based preform, since, as already explained, the compression mold can be designed to have a higher quality compared to the casting mold.

[0052] It can be provided that the expandable tool remains in the expanded state during the exposure to the microwaves. In other words, the expansion of the expandable tool and the exposure of the pressed preform to the microwaves are carried out simultaneously. The preform remains in the pressing mold.

[0053] The pressure on the wall of the wet fiber-based preform can be maintained. Furthermore, since the expandable tool is kept inside the wet fiber-based preform, the expandable tool is supported from the inside and prevented from undesired deformation. This also improves the surface quality of the preform.

[0054] The fiber-based preform can be introduced into a microwave-reflecting microwave chamber before exposure to microwaves, in particular together with a compression mold.

[0055] This can increase the effectiveness of the microwaves. Microwaves that are not directly absorbed by the wet fiber-based preforms are usually reflected by the inner walls of the microwave chamber, thereby increasing the probability that these microwaves still hit the preforms to be dried.

[0056] It is generally known that excitation with microwaves can cause molecular vibrations, and that the vibrations generate heat. For example, water has a natural frequency of 2.45 GHz. Therefore, microwaves are preferably generated at this frequency. In order to remove water or residual moisture from a wet fiber-based preform, the water is preferably heated until it evaporates and diffuses out of the wet preform.

[0057] To accelerate the drying process, the press mould and / or the microwave chamber may be preheated to a temperature above 60°C but preferably below 160°C.

[0058] This also prevents moisture escaping from the wet fiber-based preform from condensing again in the immediate vicinity of the preform and settling as droplets.

[0059] For example, conventional resistance heaters can be used for heating. Additionally or alternatively, it is envisaged to blow in a suitably heated fluid, such as air, so that the corresponding element reaches the desired temperature.

[0060] The die may additionally or alternatively be preheated, for example, by intentionally partially absorbing the microwave radiation in the die itself in the order of at most 10%, preferably at most 5%, of the microwave radiation, or by releasing energy to the die from the steam generated during drying.

[0061] The moisture can be removed by forced airflow. The moisture can be water vapor or water in liquid form.

[0062] Forced exhaust keeps moisture levels inside the device low and prevents condensation of moisture or reheating of moisture, such as reheating of water droplets by microwave radiation.

[0063] To improve drying and / or water evaporation of the wet fiber-based preform, it may also be rotated during exposure to microwaves.

[0064] This allows a more uniform energy input into the wet fiber-based preform and avoids overheating of individual points of the preform.

[0065] It can be provided that a plurality of preforms are exposed to the microwaves simultaneously. To this end, it can be provided that a plurality of preforms, in particular a plurality of dies each with a preform, are introduced simultaneously into the microwave chamber. This reduces the cycle time or increases the number of preforms dried per unit time and allows a more efficient use of the microwaves.

[0066] The preforms can each be rotated about their own axis and / or about a common axis. This enables a more efficient use of the microwaves and allows a more uniform energy input into the preforms.

[0067] Additionally or alternatively, it is also conceivable to provide one or more compression molds which can accommodate a plurality of preforms simultaneously. This simplifies the device, since each preform need not be individually manipulated when it is in a plurality of compression molds.

[0068] It has been found that a plurality of individual dies and preforms can be arranged spatially relative to one another in the microwave chamber. This arrangement has no influence on the uniformity of the energy input.

[0069] Additionally or alternatively, it can be provided that a rotating element, a so-called stirrer, is provided, in particular in the microwave chamber or at the transition of the waveguide into the microwave chamber, and that the microwaves are swirled by means of this element. The stirrer can be used to disrupt the static propagation of microwaves in the drying chamber, i.e. the microwave chamber, and to minimize areas of high microwave intensity.

[0070] Such an arrangement also has a positive effect with regard to uniform energy input.

[0071] Another way to improve the quality is to apply the microwaves in a timed manner depending on the water content of the wet fiber-based preform. Pulses can reduce the power. Typically, toward the end of the drying process, the water content in the wet fiber-based preform is low, and too high a level of energy can cause the preform to overheat at certain points. This can be prevented by reducing the power.

[0072] The microwave permeable die may be made of a material selected from a list of materials including PEI, PI, PE, POM, PEEK, wood, PTFE, ceramic, glass and PP. The die may be porous, or solid with drainage channels, or made of a fine mesh material.

[0073] It can be seen that the preform remains in the mold during the entire drying process.

[0074] It can be provided that, in order to cut the dry preform to size and thus produce a fiber-based product, the excess length is cut off by means of a laser beam.

[0075] By providing a laser or laser beam to cut to length, a very precise cut edge can be created.

[0076] It can be provided that the dry preform and the laser beam are moved relative to one another when the excess length is cut off.

[0077] The relative movement between the laser beam and the dried preform allows the laser beam to be moved so that it maintains a constant distance from the surface of the length to be cut and also maintains a specific angle between the laser beam and the surface. In other words, this configuration allows the angle of the cut edge along the surface to remain the same over the entire length of the cut edge. This also produces a very flat cut edge. Undulation of the cut edge can be prevented.

[0078] The relative movement is preferably a rotational movement of the container relative to the laser beam, ie rather than a movement of the laser beam in the circumferential direction of the preform.

[0079] The cutting device for cutting the dried preform to size comprises a holding device for holding the dried preform. The device also has a cutting laser for generating a laser beam, wherein the laser beam of the cutting laser and the dried preform are movable relative to each other so as to cut off excess length of the dried preform by means of the laser beam.

[0080] It can be provided that the laser beam is guided in a deflection device and that the deflection device is rotated about the longitudinal axis of the dry preform in order to generate a relative movement for cutting off the excess length.

[0081] Such method steps provide for a simple method sequence which is precisely adjustable and reproducible.

[0082] The laser beam can be focused on the surface of the length to be separated by means of focusing optics, or the focus of the laser beam can be adjusted to a specific distance from the surface. This can be zero or negative so that the focus is within the material thickness.

[0083] Using this type of focusing optics and proper focusing, clean cuts can be made.

[0084] For cutting, the laser beam can be positioned and activated in the direction of the longitudinal axis above the final cut surface.Laser cutting has a vertical movement component up to the cutting position of the final cut surface.

[0085] In particular, this vertical movement component is also superimposed with a movement component directed in the circumferential direction of the fiber-based product, so that a substantially abrasive cut occurs.

[0086] By positioning and activating the laser beam above the final cut surface, defects that occur when the laser beam is activated can be prevented. Typically, more energy is introduced when the laser beam first passes through the object to be separated, resulting in burning of the object to be separated at certain points. By positioning the laser beam above the final cut surface, this burning at certain points is not in the area of ​​the final cut surface.

[0087] Preferably, after cutting of the final cut surface is completed, the laser beam is moved in the direction of the longitudinal axis over the final cut surface before the laser beam is deactivated.The laser cutting has a vertical movement component up to the final position in which the laser beam is deactivated.

[0088] Just as at the beginning of the cut, sometimes at the end of the cut there is also an increased energy input and a burn mark may form. The vertical movement component allows the burn mark to be moved away from the final cut surface.

[0089] Preferably, in this case, the vertical movement component also has a superimposed movement component pointing in the circumferential direction of the dried preform. Here, an abrasive cut also occurs.

[0090] The laser beam can be switched on and off as it moves downwards or upwards, and the dried preform and the laser beam also already have a component of movement pointing in the circumferential direction of the dried preform. This also reduces the risk of burning at certain points or at least the extent of burning.

[0091] Preferably, the radial distance between the focusing optics and the longitudinal axis is initially adjusted according to product-specific parameters. This ensures that the focus of the laser beam is always at the desired distance from the surface of the length to be separated, thereby producing a cut surface with a correspondingly high quality.

[0092] For each fiber-based product / dried preform, product-specific parameters can be determined individually. It is conceivable that each product is measured before the cutting process and the corresponding data are transmitted to the cutting device, which performs the cutting with static regulation accordingly.

[0093] For example, this parameter can also be adjusted for the entire batch, for example if the entire batch is manufactured within a narrow tolerance range.

[0094] In other words, a previously recorded profile can be transferred to the cutting device so that the radial adjustment of the focusing optics can be continuously adapted over the cutting length according to the profile.

[0095] However, it is also conceivable that the radial distance is continuously adapted to the contour of the dry preform during the cutting-off or cutting process.

[0096] This ensures a continuous adjustment of the radial distance, allowing the distance between the focus of the focusing optics and thus the laser beam and the surface of the length to be separated to remain the same over the entire length of the cut.

[0097] It is also conceivable that if the surface is not flat or has, for example, an unknown profile, the surface is measured virtually in real time and the radial distance of the focusing optics is adjusted continuously.

[0098] In order to improve the quality of the cut edge, flushing gas can be blown into the dry preform during the cutting process by means of a flushing device. By blowing in flushing gas in this way, dirt and particles formed during the cutting process can be blown out of the interior of the preform or dirt and particles can be prevented from settling inside the dry preform. Additionally or alternatively, provision can be made for exhaust air to be extracted from the dry preform, in particular from the interior of the dry preform, and / or from the region of the outlet nozzle by the first suction device during the cutting process.

[0099] This helps to improve the cutting quality and makes it possible to omit subsequent cleaning of the cut edges.

[0100] Additionally or alternatively, provision can be made for the deflection device to be exposed to flushing gas during the separation process.

[0101] On the one hand, this prevents dust or dirt particles from being deposited and / or settled in the deflection device, in particular on the deflection mirrors arranged therein or thereon. On the other hand, by exposing the deflection device to flushing gas at the outlet nozzle, a shielding gas flow can be generated, which shielding gas flow provides protection from external influences in the cutting area. Such a shielding gas flow can in particular prevent dirt or dust particles from entering the laser beam.

[0102] After the separation process, the separated excess length can be stripped from the cutting device by means of a stripping ring.

[0103] The excess length can thus be handled specifically, for example by conveying it to a separate hopper or container.

[0104] After cutting to size, powder coating can be applied to the cut-to-size openings of the dried preform. By applying powder coating, the cut edges can be sealed.

[0105] The powder coating can also be applied to the inside of the dried preform after it has been cut to size. This makes it possible to seal the inside of the preform.

[0106] Furthermore, it can be provided that the powder coating is applied to the outside of the neck region of the dried preform after it has been cut to size. However, at least a portion of the outside of the dried preform remains uncoated, and thus the outside is uncoated in certain areas.

[0107] By coating the outside of the neck area it may also be sealed during use and / or made more durable.

[0108] The uncoated areas on the outside of the preform allow the product to be recycled. The uncoated areas provide an erosion surface where the product can be broken up or softened using water. Thus, the product can be recycled more easily.

[0109] Fusible polymers can be applied as powder coatings.Polymers have favorable properties and are easy to handle.

[0110] The powder coating can be applied electrostatically. In particular, it can be provided that the conductive mold surrounding the die is charged with a charge of opposite polarity to the powder. The powder is then deposited in particular on the inner side of the preform and adheres thereto.

[0111] The powder coating can then be melted in an oven under the influence of heat so that a continuous film is formed. Thus, the applied powder coating is exposed to thermal energy and the powder is converted into a melt. The melting process produces a uniform film that provides a proper seal. Preferably, the film extends from the inside via the opening cut to size to the outer area of ​​the neck and forms a continuous seal in this area.

[0112] Provision may be made to test the dried preforms for leaks. This prevents defective products from being sold.

[0113] After sealing, i.e. after melting the powder coating and subsequently cooling it, the product can be poured into the dry preform, which can then be closed by means of the closure. Thus, a closure is produced for conveying and protecting liquid products. In particular, by sealing the edges for cutting to size, a reliable seal can be produced in this area by means of a suitable sealing cone or sealing plane, which is made, for example, of a sealing material such as a liner. BRIEF DESCRIPTION OF THE DRAWINGS

[0114] The method according to the present invention is explained below with reference to the schematic diagram. In the accompanying drawings:

[0115] Figure 1 : shows the casting mold;

[0116] FIG. 2A to FIG. 2E : shows the various method steps;

[0117] Figure 3 : shows the device before exposure to microwaves;

[0118] Figure 4 : shows the Figure 3 Devices;

[0119] Figure 5 : is a perspective view of the cutting device;

[0120] Figure 6 :It is through Figure 5 A cross-sectional view of a cutting device;

[0121] Figure 7 :yes Figure 6 Detailed view of

[0122] Figure 8 : is a perspective view of a dried preform;

[0123] Fig. 9 : shows the powder coating process;

[0124] Fig.10 : shows the drying step of the powder coating process;

[0125] Fig.11 : Leak test is shown;

[0126] Fig.12 : shows the closing process;

[0127] Fig.13 : shows an example of a further typical product which can be manufactured by means of the method according to the invention;

[0128] Fig.14 : shows an example of a typical fiber-based closure that can be produced by means of the method according to the invention. DETAILED DESCRIPTION

[0129] In the following figures, individual method steps of the method according to the invention are described respectively. Figures 1 to 2E The preparation of the casting mold and the introduction of the pulp into the casting mold are described. Figure 3 and Figure 4 Possible and preferred drying steps are described. Figures 5 to 8 A preferred method for cutting the dried preforms to size is described. Finally, Figures 9 to 12 describes the final processing steps, and Fig.13 and Fig.14 Possible applications are described.

[0130] Figure 1 A casting mold 70 for a preform of a container in the form of a bottle is shown. In this case, the casting mold 70 has two casting mold halves, wherein Figure 1 Only one half is shown in FIG. 1 . A cavity 72 is arranged in the casting mold 70, which is surrounded by a liquid-impermeable outer boundary 73. The cavity 72 is water-permeable and is formed in this case by a metal grid or screen. The liquid-impermeable outer boundary 73 has a hollow space 74 in which the cavity 72 is arranged. The casting mold 70 has a plurality of discharge openings 71. The discharge openings 71 connect the outside of the casting mold 70 to the hollow space 74. The casting mold 70 also has an inlet opening 75 directly leading to the inside of the cavity 72. The discharge openings 71 are arranged at different heights and therefore different discharge levels can be defined.

[0131] In this case, the position marker "height" is based on Figure 1 The illustration shown in and is therefore defined based on the container in its use position, ie in an upright form with a discharge opening at the top and a container base at the bottom on which the container stands.

[0132] Valves are arranged at both the inlet opening 75 and the outlet opening 71 in order to close each of the openings.

[0133] As shown here, the inlet opening 75 may be provided with a branch 76 which may also be closed.

[0134] FIG. 2A to FIG. 2E The figures each show a method step or a process step. Figure 1 A simplified cross section of the casting mold 70. Figure 2A It can be seen that the casting mold 70 is filled with process liquid 95, so that a liquid reservoir 96 is formed in the casting mold 70. In this case, the casting mold 70 is closed, that is, the outlet opening 71 is closed. The liquid reservoir 96 fills the entire hollow space 74 and also flows through and fills the cavity 72 likewise.

[0135] The casting mold 70 is connected by means of its inlet opening 75 to a corresponding reservoir or process step in which the pulp 90 is located. Figure 2A In the illustration of , pulp 90 has been applied to the liquid reservoir 96 in the casting mould 70. The branch 76 at the inlet opening is closed.

[0136] Now from Figure 2B It can be seen that the liquid reservoir 96 is discharged from the casting mold 70 in a targeted manner, in particular in this case in the direction of the arrow P1 through the discharge openings 71 which are arranged at the top in this illustration. For this purpose, these discharge openings are opened. The pulp 90 now flows out of the reservoir, through the inlet openings 75 and into the interior of the cavity 72. The fibers located in the pulp 90 remain inside the casting mold 72, in particular on the walls of the cavity 72. Here, the wall 101 of the subsequent preform is constructed. The fibers are actually filtered out of the pulp, so that only the liquid part of the pulp enters the hollow space 74. This is shown by the hatching that is different from the hatching of the pulp 90. By opening or closing the discharge openings 71 accordingly, the corresponding flow in the casting mold 70 can be adjusted so that the fibers are deposited at the desired position or point in the cavity 72.

[0137] For example, in the present illustration, once sufficient pulp has been deposited in the upper region, the now open discharge opening 71 can be closed and the other discharge openings 71 can be opened. This can be done, for example, from Figure 2C Here, relative to the Figure 2B The open discharge opening 71 located further below is open. The process liquid 95 now flows out of the mold in the direction of arrow P2 and the pulp 90 settles at other points within the cavity 72. The wall 101 is further constructed. In the next step, the lowermost discharge opening 71 can be opened. This Figure 2D The process liquid 95 still remaining in the casting mould 70 is now completely displaced by the pulp 90 and flows in the direction of the arrow P3. The construction of the wall 101 of the preform 60 is now complete.

[0138] Then, the valve at the inlet opening 75 is closed so that no more pulp can flow in. The liquid still remaining in the casting mold 70 is completely drained and the resulting preform 60 is removed from the casting mold. The casting mold 70 is now empty, although fiber residues from the pulp 90 may still adhere to the cavity 72. These fiber residues can be backwashed. In this case, process liquid 95 is introduced into the casting mold 70 through the discharge opening 71. This Figure 2E As indicated by arrow P4. As indicated by arrow P5, when process liquid flows in, fiber residues are released from cavity 72 and discharged via branch 76. For this purpose, inlet opening 75 is closed and branch 76 is opened. This prevents process liquid from flushing into the pulp reservoir. After a period of time, discharge opening 71 is closed and the flushing process is completed. At this point, as shown in FIG. Figure 2A As shown, the interior of the casting mould, ie the hollow space 74 and the cavity 72, is again filled with process liquid 95. The branch 76 can be closed and new pulp can be applied to the liquid reservoir by opening the inlet valve 75.

[0139] The wet fiber-based preform 60 is removed from the casting mold 70 by a suitable conveying device. To this end, the casting mold 70 is opened. The wet fiber-based preform 60 is then inserted into the opened compression mold 20, which is formed of two parts for this purpose.

[0140] Figure 3 An apparatus 200 is shown for reducing the water content in a fiber-based preform prior to exposure to microwaves. In this case, the fiber-based preform 60 is a container in the form of a bottle. The process is a drying step. In this case, microwave radiation is used to perform this step. This step will be described below with reference to the apparatus 200.

[0141] The device 200 has a microwave chamber 40 which is closed by a cover 41. In the cover 41 there is an exhaust opening 42 through which compressed air and / or moisture (such as water or water vapor) can be discharged. The microwave chamber 40 also has a bottom plate 43. A plurality of openings 44 are arranged in the bottom plate, through which supply air can be introduced into the microwave chamber 40. The device 200 also has a device 50 for generating microwaves. In this case, it is designed as a magnetron. The device 50 for generating microwaves is connected to the microwave chamber 40 by means of a waveguide 51. The waveguide 51 is rectangular.

[0142] In the device 200, the die 20 is arranged in a microwave chamber 40. A wet fiber-based preform 60 is arranged in the die 20. The wet fiber-based preform was taken out of the mold before being introduced into the die 20 and now has a water content of about 75%. After the wet fiber-based preform 60 has been introduced into the die 20, the expandable tool 30 is introduced into the interior of the wet fiber-based container 100. As a result of the expansion of the expandable tool 30, the walls of the preform 60 are pressed against the inner walls of the die 20 and the water or moisture located in the wet fiber-based preform 60 is partially pressed out. For this purpose, the die 20 is designed to be water-permeable. Water permeability can be achieved by means of porosity; alternatively, separate channels or openings can be provided in the die. Thus, water can be discharged through the gaps or openings at the parting point of the die. The water or more precisely the moisture in the wet fiber-based preform is discharged according to the pressure. Figure 3 In the illustration of FIG. 4 , the water droplets are shown in a stylized manner by water droplets. These water droplets can drip onto the floor 43 of the microwave chamber and drain through the opening 44. After this step, the fiber-based container 100 has a water content of about 50%.

[0143] Figure 4 The application of microwaves to a wet fiber-based preform 60 is shown according to Figure 3 Therefore, Figure 4 The actual drying process is shown. In the device for generating microwaves 50, microwaves are generated accordingly, which are introduced into the microwave chamber 40 via the waveguide 51. The microwaves heat the moisture in the fiber-based preform 60; in other words, the molecules begin to vibrate. The moisture begins to evaporate and leaves the preform 60 through the microwave-permeable die 20. Figure 4 , the expandable tool 30 is shown in a non-expanded state, but the expandable tool 30 can also remain expanded during the process shown here. Moisture, which is shown here in a stylized form by wavy lines, enters the microwave chamber 40. In order to prevent this moisture from settling in the microwave chamber 40, air is blown in through openings 44 in the bottom plate 43 of the microwave chamber 40. This blown air flows out of the microwave chamber 40 through the exhaust openings 42. This generates a flow within the microwave chamber 40, by means of which moisture can be discharged from the microwave chamber 40.

[0144] In this case, the die 20 may be provided with a moisture removal channel, to which a gap arranged on or in the parting surface of the die 20 leads. In this configuration, moisture is not discharged from the entire die 20 into the microwave chamber 40 as shown in the figure, but is collected in the moisture removal channel. Therefore, moisture can be discharged directly from the die 20 to the outside of the microwave chamber 40. The corresponding exhaust opening in the microwave chamber 40 is directly connected to the moisture removal channel.

[0145] In this case, the holding means for the microwave-permeable die 20 are designed as an integral part of the cover 41. However, it is also conceivable, for example, that the device 200 is formed in two parts, i.e., consists of two halves and, if necessary, of a separate base plate. For example, the die 20 can be held and pressed together by corresponding elements on the respective halves of the device 200.

[0146] After this drying step, the now dried preform 61 is removed from the die 20. To this end, the die is opened. Using a suitable conveying device, such as a gripper, the dried preform 61 is fed to a device for cutting the dried preform to size and the dried preform is cut to size accordingly. This step will be explained below with reference to the cutting device 400.

[0147] Figure 5 is a perspective view of a cutting device 400. The cutting device 400 comprises a holding device 450 for holding a dried preform 61. The cutting device 400 also comprises a cutting laser 420, which in this case is arranged immovably on the cutting device 400. Above the dried preform 61, a support 432 is arranged, on which a rotary bearing 431 is arranged. The support 432 is vertically movable along a longitudinal axis X. The longitudinal axis X substantially corresponds to a longitudinal axis through the dried preform 61 and, in the case of a rotationally symmetrical dried preform 61, corresponds, as shown here, to the axis of rotation.

[0148] For the sake of greater clarity, the supply device for supplying the dried preforms 61 and for removing the dried preforms 61 are not shown.

[0149] Figure 6 is through according to Figure 5 4. The cutting device 400 is a cross-sectional view of the cutting device 400. The cutting extends transversely to the longitudinal extent of the laser 420 through the longitudinal axis X. The holding device 450 is arranged in the region of the cutting device 400, in Figure 6 The dried preform 61 is held in the cutting device 400 by means of the holding device 450. A vertically displaceable support 432 is arranged above the holding device 450, on which a rotary bearing 431 is arranged. A deflection device 430 for guiding the laser beam 421 is arranged on the rotary bearing 431. The laser beam 421 is generated by means of a laser 420. The laser beam 421 is generated so that it radiates substantially from the output side of the laser 420 in the direction of the longitudinal axis X. The laser beam 421 is deflected by means of the deflection device 430 so that it is directed substantially at a right angle to the dried preform 61. This will be referred to below. Figure 7The rotation bearing 431 is arranged so that the deflection device 430 can be moved about the longitudinal axis X, wherein the longitudinal axis X and the center of rotation are substantially located one above the other. In this case, the deflection device comprises individual tubes 424, 425, 426 and 427, each of which is arranged at an angle to each other. At each intersection of the individual tubes, a deflection mirror 423 for deflecting the laser beam 421 is arranged in the tube. Figure 7 Explain their function. The length of the tube 424 of the deflection device 30 is variable, so that the support can be moved vertically together with the rotary bearing 431 and the remaining elements of the deflection device 430. The length of the tube 425 of the deflection device 430 is also variable, so that the radial distance between the tubes 426 and 427 and the longitudinal axis X is adjustable.

[0150] Figure 7 Shows Figure 6 Detailed view of the deflection device 430. As shown, a plurality of deflection mirrors 422 are arranged in a deflection device 430. Downstream in the direction of the laser beam, i.e. downstream in the radiation direction, a safety element 423 is arranged for each deflection mirror 422, which safety element is designed as a metal plate in this case. A focusing optical device 440 for focusing the laser beam is also arranged on the deflection device 430, and an outlet nozzle 428 is arranged downstream in the beam direction. As with Figure 6 As explained, the radial distance of the deflection device or of its elements downstream of the rotary bearing 431 is adjustable. To this end, an actuator 433 is arranged below the rotary bearing 431. By actuating the actuator 433, the distance between the focusing optics 440 and the longitudinal axis X is adjustable. Thus, the distance between the focus of the laser beam 421 and the surface of the length 62 to be ablated can be adjusted (see in this regard). Figure 8 ).

[0151] In this case, the deflection device 430 forms a substantially closed system into which flushing gas can be introduced, which flushing gas flows through the outlet nozzle 428 during operation. Figure 7. The holding device has two grippers 451 and 452, which hold the dry preform 61 on both sides. A flushing device 480 is introduced into the dry preform 61, by means of which flushing gas can be introduced into the interior of the dry preform 61. During operation, or during the cutting process, the introduction of flushing gas can prevent dirt or dust particles from settling inside the dry preform 61. The second suction device 481 is integrally formed in the flushing device 480 and extracts the flushing gas introduced into the dry preform 61 together with any dirt particles it may contain above the dry preform 61 or above the openings in the dry preform 61. The first suction device 460 is arranged outside the dry preform 61, in particular in the area of ​​the outlet nozzle 28. The first suction device 460 extracts dirt and dust particles formed outside the dry preform 61, and at least part of the flushing gas from the deflection device 430 can be collected again.

[0152] according to Figure 7 The illustration of shows the cutting device 400 during operation. Before reaching this state, the deflection device 430, the first suction device 460 and the flushing device 480 are arranged vertically above the dried preform 61. All these elements are fixed together on the rotary bearing 431 and can be moved vertically together with the support 432.

[0153] In order to cut off the excess length 62 of the dried preform 61 (see Figure 8 ), these aforementioned elements are moved in the vertical direction towards the dry preform 61, wherein during the vertical movement the rotary bearing 431 together with the deflection device 430 and all elements arranged on the rotary bearing 431 begin to rotate about the longitudinal axis X. Also, already at this point, the laser is activated so that it has reached its preset power during the vertical displacement process and during the rotation and shoots through the dry preform 61 above the final cut edge 65 (see in this regard Figure 8 ).

[0154] After reaching the final vertical position, the rotary bearing 431 moves another 360°, and then the support 433 moves upward again in the vertical direction, and then the laser 420 is turned off.

[0155] exist Figure 7 , a protection plate is also shown opposite the outlet nozzle 428, which protects the laser beam from uncontrolled propagation in the event of a fault.

[0156] Figure 8is a perspective view of a dried preform 61. In the upper region, i.e. in the neck region, the dried preform 61 is shown cut so that the cut edge 65 is visible. The cut thus extends only through the excess length 62. After the cutting process, the cut edge 65 forms the final upper edge or upper opening of the dried preform 61 to which a corresponding cover can be applied.

[0157] After this treatment, the dried preform 61 , which is now cut to size and thus already in the form of a fiber-based product, can be supplied for further processing steps.

[0158] For example, in a subsequent step, the interior of the dried preform 61 can thus be coated and / or the dried preform 61 can be supplied to a filling system.

[0159] The following will refer to Fig. 9 The coating steps are explained. The preform 61, which is now cut to size, is fed to a powder coating system (not shown in detail here). In the next step, an electrostatically charged spray gun 35 is introduced into the preform 61 cut to size. The spray gun is located in a housing (also not shown here) with an opposite charge. Due to the electrostatic charge of the applied powder, the powder adheres to the inner side 63 of the preform 61 cut to size.

[0160] like Fig.10 As shown, the now coated cut-to-size preform 61 is transferred into an oven and exposed to heat energy. This causes the powder coating to melt so that a continuous uniform film is formed. The preform 61 is thereby sealed.

[0161] Then, if Fig.11 As shown, the preform 61 can be subjected to a leak test by means of a corresponding testing device 500 .

[0162] Then, if Fig.12 As shown, the preform 61 may be closed by a cover 300 .

[0163] Fig.13 Examples of other typical fiber-based products that can be manufactured by means of the methods described herein are shown. Thus, a container 100 in the form of a bottle is shown. The container also includes threads on the neck of the bottle. The container 100' is in the shape of a bowl; the container 100" is in the shape of a cup.

[0164] Fig.14 An example of a typical fiber-based closure 300 that may be manufactured via the methods described herein is shown.

Claims

1. A method for producing a fiber-based product, in particular a container (100, 100', 100") or a fiber-based closure element (300) for a container (100, 100', 100"), from pulp (40), the method comprising the following steps: - providing a casting mold (70), - Introducing pulp (40) into the casting mold (70) so that a wet fiber-based preform (60) is formed - Drying the wet fiber-based preform (60) - Cutting the dried preform (61) to size by cutting off any excess length (62).

2. The method according to claim 1, characterized in that To form the fiber-based preform (60), the pulp (40) is introduced into the mold (70) by: - filling the casting mold (70) with a process liquid (95), in particular water, so that a liquid reservoir (96) is formed in the casting mold (70), - applying pulp (40) to the liquid reservoir (96) - replacing the liquid reservoir (96) by draining it through the casting mold (70) in a targeted manner.

3. The method according to claim 1 or claim 2, characterized in that: In order to dry the preform (60), at least the following steps are performed: - providing said fiber-based preform (60) in a microwave permeable press mold (20), - introducing an expandable tool (30) into said fiber-based preform (60), - expanding the expandable tool (30) so that the fiber-based preform (60) is compressed in order to reduce the water content of the fiber-based preform, - Exposing the pressed preform (60) to microwaves so as to provide a dried preform (61).

4. The method according to claim 3, characterized in that The expansion of the expandable tool (30) and the exposure of the pressed preform (60) to microwaves occur simultaneously.

5. The method according to any one of claims 1 to 4, characterized in that In order to cut the dried preform (61) to size, a laser beam (421) is used to cut off the excess length (62).

6. The method according to claim 5, characterized in that In order to cut off the excess length (61), the dry preform (61) and the laser beam (421) are moved relative to each other so that a cut-to-size opening is formed.

7. The method according to claim 6, characterized in that After the dried preform (61) is cut to size, a powder coating is applied to the cut-to-size openings of the dried preform.

8. The method according to any one of claims 1 to 7, characterized in that After the dried preform (61) is cut to size, a powder coating is applied to the inside (63) of the dried preform.

9. The method according to any one of claims 1 to 8, characterized in that After the dried preform (61) has been cut to size, a powder coating is applied to the outside of the neck region of the dried preform, the dried preform (61) remaining uncoated on its outside at least in certain areas.

10. The method according to any one of claims 7 to 9, characterized in that A fusible polymer is applied as the powder coating.

11. The method according to claim 10, characterized in that In order to apply the powder coating, the powder coating is electrostatically charged.

12. The method according to any one of claims 7 to 11, characterized in that The powder coating melts in an oven under the influence of heat, so that a continuous film is formed.

13. The method according to any one of claims 1 to 12, characterized in that The dried preform (61) is leak tested.

14. The method according to any one of claims 1 to 13, characterized in that The product is poured into the dry preform (61) and the dry preform is subsequently closed by means of a closure.

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