PRESS MOLD FOR RECEIVING A FIBER-BASED BLANK, AND METHOD FOR REDUCING THE WATER CONTENT IN A FIBER-BASED BLANK

Description

The present invention relates to a press mold for receiving a fiber-based blank, in particular for receiving a container or a fiber-based closure element, and a method for reducing the water content in a fiber-based blank, in particular in a container or in a fiber-based closure element for a container according to the preamble of the independent claims.

A fiber-based blank in the form of a container was disclosed in WO 2012/139590 A1. To produce this container, so-called pulp is injected into an upside-down mold and pressed against a corresponding wall in this mold using a flexible balloon and compressed accordingly. The pulp is compressed and heated to a temperature of around 180° C. in order to dry the container. It is also known to produce closure elements for containers from pulp.

The pulp is a mixture of fibers and water, in particular natural fibers such as hemp fibers, cellulose fibers or flax fibers or a mixture thereof. Optionally, the pulp has additives that, for example, improve the curing of the compressed pulp or have an influence on the later appearance or generally change the properties of the pulp or the later container.

The aforementioned method is time-consuming and energy-intensive. It has therefore already been suggested to improve this. WO 2018/020219 A1 introduced a further method for drying wet, fiber-based blanks. In this case too, the blanks are containers. Here, the wet pulp is also pressed together with a flexible balloon inside the casting mold. The pre-processed container is then demolded together with the balloon inside it and placed on a conveyor belt. The balloon is removed from the cold-formed container. The container is then exposed to microwaves to dry it. The blank is very sensitive to the application of force before drying and must be handled very carefully. During the drying process, the container may become deformed, for example due to uneven drying or a non-uniform layer thickness, or it may be damaged by external influences.

It is the object of the invention to remedy at least one of the disadvantages of the prior art. In particular, a device and a method are to be provided which make it possible to dry wet fiber-based blanks, in particular containers, such as bottles, cups, bowls or dishes or wet fiber-based closure elements, with low energy expenditure, while ensuring that they remain dimensionally stable.

This object is achieved by the devices and methods defined in the independent claims. Further embodiments result from the dependent claims.

A device according to the invention is provided by a press mold for receiving a fiber-based blank. The fiber-based blank can in particular be a container or a fiber-based closure element for a container. The press mold is intended for use in a microwave chamber. In addition, the press mold is permeable to microwaves. In the closed state of the press mold, at least one gap is formed inside the press mold through which moisture can escape.

By providing a microwave-permeable press mold for the fiber-based blank, a wet fiber-based blank can remain within the mold during the drying process, i.e. during exposure to microwaves. The blank is thus protected against external influences and damage or deformation is prevented. By providing the wet fiber-based blank inside the microwave-permeable mold, it can also be ensured that said blank is accessible to the microwaves from all sides and drying can therefore be carried out from all sides. After this drying step, the wet fiber-based blank has a water content of approximately 5% to 12%.

In the present method, the wet fiber-based blanks are typically shaped as already known in the prior art. In other words, pulp is introduced into a porous casting mold or into a solid casting mold having water-draining channels, the inlets of which are covered with screens or the openings of which are small enough that the fibers of the pulp cannot penetrate, and the fibers of the pulp are applied to the inner wall of the casting mold so as to form a wall of a blank. Once the wall is sufficiently thick, the swelling of the pulp stops. The semi-finished product now present, i.e., the wet fiber-based blank, is removed from the casting mold and introduced into the microwave-permeable press mold and thus provided in the press mold. At this point, the wet fiber-based blank has a water content of approximately 75% or less, such that it can be transported between the processing stations in a dimensionally stable manner.

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

Typically, the press mold can have an inner wall that is designed with a higher surface quality compared to the inner wall of the casting mold.

Preferably, after the fiber-based blank has been provided in the press mold, an expandable tool is introduced into the fiber-based blank. By expanding the expandable tool, the water content of the fiber-based blank can be reduced in a first step by compressing a wall of the blank. At this point, the wet fiber-based blank has a water content of approximately 50%-60%.

The at least one gap on the press mold allows the displaced moisture, which in this case is substantially water, to escape from the press mold.

Accordingly, it is not necessary to make the press mold as such water-permeable. On the one hand, this makes it possible to produce the surfaces of the press mold with a higher quality, and on the other hand, any pores or channels in the press mold do not have to be laboriously cleaned after the press mold has been used.

The moisture can also be removed in a targeted manner through a gap, or the regions in which the moisture is removed can be selected in a targeted manner.

The gap also allows moisture to be removed in a later step, namely during exposure to microwaves. However, in this step the moisture is typically present as vapor.

A gap within the meaning of the present description is an opening with an elongated extension. In other words, the opening has a length whose dimension is several times greater than the width dimension, in particular more than twenty times. A gap is also arranged in each case in such a way that moisture can escape from the inside of the press mold, i.e. from a cavity, to the outside. In other words, the gap is an opening that provides a passage arranged radially with respect to a longitudinal axis of the press mold.

It can be provided that the at least one gap is formed in a region of the press mold that corresponds to a region on the fiber-based blank that is removed prior to use of a product made from the fiber-based blank. It may be provided that additional further gaps are arranged on the press mold.

Under certain circumstances, the gap may leave machining marks on the surface of the blank. If the gap is formed in a region that will later be cut off from the blank, this circumstance is irrelevant. Any changes to the surface are therefore not visible on the finished product, as these regions are cut off accordingly.

In particular, it can be provided that the at least one gap is formed in a region of the press mold which corresponds to a neck of the blank.

The neck of the blank can be selected to be correspondingly longer in relation to the finished product and the protruding region can be easily cut off.

As already explained, the press mold can be formed in two or more parts. Accordingly, it has one or more mold parting lines. It can be provided that the gap is formed on at least one of the mold parting lines. This is as an alternative or in addition to a gap in a region that is later cut off from the blank, as described above.

The formation of the gap at a mold parting line enables simple production of the gap, since the mold parting line is easily accessible with tools during production. In addition, a gap at the mold parting line can be cleaned easily and inexpensively.

If the mold parting line of the press mold extends in the same region as a corresponding mold parting line of a casting mold, corresponding defects that arise on the blank after casting can be captured at the same location in the press mold. This means that the blank is not subjected to unnecessary stress.

In particular, provision may be made to divide the gap between the two elements of the mold parting line. In other words, in the case of a two-part mold, half on each part of the mold. However, it would also be possible and conceivable to provide the gap in only one of two mold halves.

In other words, the press mold halves do not touch each other in the region of the cavity, i.e. on the inner wall of the cavity, but are spaced apart by the gap. In the radial direction outwards, this gap can widen and form a channel, which narrows again as the radial distance to the center of the press mold increases. The two press mold halves then rest on top of each other such that the channel is closed. When the press mold is completely closed, the mold parting line forms the gap in the direction towards the inside of the press mold.

Preferably, the at least one gap is formed circumferentially along the entire mold parting line.

This increases the opening cross-section through which the moisture can escape. In addition, by arranging the gap along the entire mold parting line, the entire blank is also substantially accessible from all sides. This is also advantageous because a visible marking will appear on the product in this region due to the casting process. By arranging the gap at the same location, an additional machining mark can be prevented.

It is conceivable that the press mold is formed in two parts in the region of a container body and additionally has a separate one-part shoulder region and/or a separate one-part floor region.

As already explained, the at least one gap can open into a moisture-discharging channel which is arranged within a wall of the press mold. In other words, the gap can spread out and expand/enlarge in the direction into the press mold such that a corresponding channel is formed. The moisture can be discharged within this moisture-discharging channel.

By providing a channel, it can be ensured that even larger amounts of moisture can be discharged without causing a build-up in the region of the gap. A corresponding channel also makes it possible to create a forced flow to discharge the moisture.

The at least one gap can have a width of 0.04 mm to 0.1 mm, in particular up to 0.4 mm. The preferred width is from 0.6 mm to 0.25 mm.

On the one hand, these values are large enough that a corresponding amount of moisture can be discharged, but on the other hand, small enough that no marks remain on the fiber-based blank.

The length of the gap is many times greater, preferably at least 20 times, preferably 100 times greater than its width. In particular, the length of the gap extends along the press mold over at least 25% of the inner contour, preferably in the axial direction, i.e. in the direction of the longitudinal axis of the press mold or of the fiber-based blank formed therein.

Provision may be made for additional openings or gaps to be provided in or on the press mold for discharging moisture. In particular, with certain geometries of the blank it may be necessary or advantageous to discharge moisture at other critical locations in addition to a gap at the mold parting line.

The moisture-discharging channel can be connected to a device for generating a negative pressure or an overpressure, so that a specific flow can be created in the moisture-discharging channel. This allows the moisture to be discharged more quickly and in a more targeted manner.

In addition, it may also be provided to temper and/or dry the flow in this channel. If an appropriate temperature, for example an elevated temperature, is provided in the channel, vapor can be prevented from condensing as moisture in the form of water in the channel.

Openings, holes or channels that have a direct connection to the outside can open into the moisture-discharging channel, such that the moisture can be discharged more quickly. In addition, corresponding channels also allow moisture to be discharged at specific locations along the moisture-discharging channel, so that moisture discharge can be accelerated in preferred regions.

The press mold may have a substantially uniform wall thickness. This ensures that the blank in the press mold is exposed substantially uniformly to microwaves and that these act correspondingly uniformly on the blank.

Bearing elements can also be provided on the press mold in order to support the press mold. Typically, a press mold as described here is relatively thin-walled and/or made of at least partially elastic materials. Deformation of the press mold can be prevented by using appropriate bearing elements.

The microwave-permeable press mold can be made of a material selected from the list of materials comprising PEI, PI, PE, POM, PEEK, wood, PTFE, ceramic, glass and PP.

A method according to the invention for reducing the water content in a

fiber-based blank, in particular in a fiber-based container or a fiber-based closure element for a container, comprises the steps of:

• • providing a wet fiber-based blank in a press mold, in particular in a press mold as described here,
  • introducing an expandable tool into the wet fiber-based blank,
  • expanding the expandable tool such that moisture displaced by the expansion is discharged through at least one gap on the press mold.

This enables moisture to be discharged from the blank in a targeted manner and the moisture content of the blank to be reduced accordingly, such that it has a residual moisture content of less than 15%, in particular between 6% and 12%.

The fiber-based blank is preferably provided in a microwave-permeable press mold.

The wet fiber-based blank is preferably exposed to microwaves after being provided in the press mold.

It can be provided that the expandable tool remains in the expanded state during exposure to microwaves.

Pressure on the wall of the wet fiber-based blank can be maintained. In addition, as the expandable tool remains inside the wet fiber-based blank, it is supported from the inside and unwanted deformation is prevented. This also improves the surface quality of the blank.

In particular, the blank is exposed to microwaves when the expandable tool is pressurized and expanded.

Exposure to microwaves can, in particular, convert the moisture in the fibers into a vaporous phase such that it can escape from the fibers. This vaporous or gaseous phase is preferably discharged through the at least one gap.

It can be provided that the moisture is discharged by means of a forced flow. A forced air flow can accelerate the discharge of the moisture.

The forced flow allows the moisture to be discharged from the microwave chamber in particular.

Additionally or alternatively, for this purpose, in the press mold a moisture-discharging channel can be provided into which the at least one gap opens. In this moisture-discharging channel, the flow can be generated by negative pressure or by overpressure. Transport into a moisture-discharging channel can reliably prevent moisture from building up at the gap.

A region of the blank, at which region the at least one gap of the press mold opens, can be cut off from the blank after the water content or moisture has been reduced. Accordingly, any marks that have formed can be removed from the finished product such that it has a uniform surface.

Openings, holes or channels that have a direct connection to the outside can open into the moisture-discharging channel, such that the moisture can be discharged more quickly. In addition, corresponding openings also allow moisture to be discharged at specific locations along the moisture-discharging channel, so that moisture discharge can be accelerated in preferred regions. The channel can be formed in the region of a parting plane as described here.

The fiber-based blank can be introduced into a microwave-reflecting microwave chamber before exposure to microwaves, in particular together with the press mold.

This can increase the effect of the microwaves. Microwaves that are not directly absorbed by the wet fiber-based blank are typically reflected by the inner wall of the microwave chamber, thereby increasing the probability that these microwaves will still hit the blank to be dried.

It is generally known that excitation with microwaves can cause molecules to vibrate and that this vibration generates heat. Water, for example, has a natural frequency of 2.45 GHz. The microwaves are therefore preferably generated at this frequency. In order to remove the water or residual moisture from the wet fiber-based blank, the water is preferably excited, and thus heated, until it evaporates and diffuses out of the wet blank.

In order to accelerate the drying process, the press mold and/or the microwave chamber may be preheated to a temperature higher than 60° C. but preferably lower than 160° C.

This also prevents the moisture that escapes from the wet fiber-based blank, in particular through a gap on the press mold, from condensing again directly in the immediate vicinity of the blank, for example inside the microwave chamber, and precipitating as droplets. Such precipitation leads to a reduction in efficiency, since this precipitation is reheated continuously by the energy introduced.

The press mold and/or microwave chamber can be heated or preheated using conventional resistance heaters, for example. Additionally or alternatively, it is conceivable to blow in an appropriately heated fluid, for example air, such that the respective elements reach the desired temperature.

An additional or alternative way to preheat the press mold could, for example, be through deliberate, partial absorption of the microwave radiation in the press mold itself in the order of a maximum of 10%, preferably a maximum of 5% of the microwave radiation, or through the release of energy to the press mold from the vapor generated during drying.

It may be possible to discharge the moisture by means of a forced air flow. The moisture can be water vapor or water in its liquid form.

If the press mold is provided with a moisture-discharging channel, the forced air flow can additionally or alternatively also form in this channel.

Forced discharge can keep the moisture inside the device at a low level and prevent or at least reduce condensation of the moisture or reheating of the moisture, for example of water droplets by microwave radiation.

In order to improve the drying and/or evaporation of moisture from the wet fiber-based blank, provision can also be made to rotate it during exposure to microwaves.

This makes the energy input into the wet fiber-based blank more uniform and overheating of individual locations of the blank can be avoided.

It may be possible to expose multiple blanks to microwaves at the same time. For this purpose, provision can be made for multiple blanks, in particular multiple press molds with one blank each, to be introduced into the microwave chamber at the same time. This reduces the cycle time or increases the number of dried blanks per time unit and enables more efficient use of the microwaves.

The blanks can each be rotated around their own axis and/or around a common axis. This enables more efficient use of the microwaves and allows a more uniform energy input into the blanks.

Additionally or alternatively, it would also be conceivable to provide one or more press molds that can accommodate multiple blanks at the same time. This simplifies the device because each blank does not have to be manipulated individually when it is in a multiple press mold.

It was found that multiple individual press molds, including blanks, can be arranged spatially in relation to one another in any way in the microwave chamber. The arrangement has no influence on the uniformity of the energy input.

Additionally or alternatively, provision may be made for a rotating element, a so-called stirrer, to be provided, in particular within the microwave chamber or at the transition of a waveguide to the microwave chamber, and to swirl the microwaves with this element. A stirrer can be used to disrupt the static propagation of the microwaves within the drying chamber, i.e. the microwave chamber, and to minimize regions of high microwave intensity.

Such an arrangement also has a positive effect in terms of a uniform energy input.

Another way of improving quality can be achieved by applying the microwaves in a pulsed manner depending on the water content of the wet fiber-based blank. The pulsing can reduce the power. Typically, towards the end of the drying process, the water content in the wet fiber-based blank is lower and an excessive level of energy can cause the blank to overheat at certain locations. This can be prevented by reducing the power.

The press mold can be porous or solid with water-discharging channels or made of a fine-mesh material.

The method and the press mold as described herein are preferably used in combination with a device for reducing the water content in a fiber-based blank, in particular for reducing the water content in a fiber-based blank as described herein. The device comprises a microwave chamber for introducing a wet fiber-based container and at least one device for generating microwaves. The device also has an apparatus for supplying and discharging media from the microwave chamber. In particular, this concerns the supply and discharge of compressed air and moisture.

One or more apparatuses for supplying and discharging media can be arranged such that they are connected to the moisture-discharging channel of the press mold when used according to the invention.

By means of such supply apparatuses and discharge apparatuses, it is possible to generate, within the microwave chamber, a specific air flow with which moisture which is generated by exposure to microwaves and penetrates into the microwave chamber or possibly penetrates into the moisture-discharging channel, can be discharged.

The device for generating microwaves can be connected to the microwave chamber by means of a waveguide.

This connection allows the device for generating microwaves to be arranged at a spatial distance from the microwave chamber and the microwave radiation generated by this device to be introduced into the microwave chamber in a targeted manner.

The waveguide preferably has a rectangular cross-section, with its longer side typically aligned in the direction of a longitudinal axis of the microwave chamber. The longitudinal axis of the microwave chamber corresponds substantially to the longitudinal axis of the fiber-based blank or container. This is determined by a connection between a floor of the blank and a casting opening of the blank or the container.

Provision may be made for a stirrer to be provided within the microwave chamber, in particular at the transition between the waveguide and the microwave chamber, and for this stirrer to be used to swirl the microwaves.

Additionally or alternatively, openings may be provided along the wave-guide which are connected to the microwave chamber and through which the microwaves can propagate into the microwave chamber. This enables the entire unit to have a reduced size.

The device may have a cover for closing the microwave chamber. In this case, an exhaust air opening can be arranged in the cover. This opening thus corresponds to an apparatus for supplying and discharging a medium from the microwave chamber, in particular compressed air and moisture.

A cover allows the microwave chamber to be easily closed and the exhaust air opening to be precisely aligned, such that a targeted air flow can be generated within the device, i.e. within the microwave chamber.

Provision may be made for multiple exhaust air openings to be provided. This firstly increases the capacity and secondly allows multiple flows to be provided.

Additionally or alternatively, the microwave chamber may be divided, so that the microwave chamber consists of two identical housing parts or of housing parts of different sizes and shapes.

It may be provided that each half of the microwave chamber is assigned to one press mold half. For example, each press mold half can be connected to a corresponding half of the microwave chamber.

The microwave chamber may additionally or alternatively have a floor. A plurality of openings is arranged in the floor to allow air to enter the microwave chamber. These openings thus correspond to an apparatus for supplying and discharging a medium from the microwave chamber, in particular compressed air and moisture.

Such openings can also be formed as an integral part of the press mold. In this case, the floor of the microwave chamber may simultaneously form part of the press mold, in particular a floor of the press mold. This floor of the press mold preferably ends in a microwave-tight tube. This firstly prevents microwaves from escaping from the microwave chamber and secondly allows moisture to be discharged and/or compressed air to be supplied to create a forced flow.

It can be provided that the device for reducing the water content in a fiber-based container has multiple devices for generating microwaves. Each of the plurality of devices for generating microwaves may be connected to the microwave chamber by a waveguide.

The individual devices for generating microwaves can thus introduce their generated microwave radiation into the microwave chamber at different locations. At the same time, each of the devices can be controlled separately and can emit microwave radiation with a different power. The drying of the blank can be carried out in a correspondingly targeted manner, whereby it can be subjected to different power levels at different locations if necessary, so that the drying process is uniform overall. “Uniform” in this case means that the wet fiber-based container reaches a predefined water content, which is achieved simultaneously throughout the entire container.

For this purpose, it can be provided that the waveguides are arranged at different angles, and/or along the longitudinal axis at different heights and/or, in relation to the longitudinal axis, with different orientations of the longer side of the respective rectangular cross-section of the waveguide.

Preferably, the device comprises a holding device for the microwave-permeable press mold. The microwave-permeable press mold can thus be arranged and/or supported within the device, in particular within the microwave chamber.

It may be possible to expose multiple blanks to microwaves at the same time. For this purpose, it can be provided that the device has multiple holding devices in order to hold multiple press molds in the microwave chamber at the same time. This reduces the cycle time and enables more efficient use of the microwaves.

The holding devices can each be designed to rotate around their own axis and/or around a common axis. This enables more efficient use of the microwaves and allows a more uniform energy input into the blanks.

Alternatively, it would also be conceivable to provide a holding device that can hold multiple press molds at the same time or can hold a multiple press mold. This simplifies the device because each press mold does not have to be manipulated individually when it is in the microwave chamber.

The holding device can also be designed in such a way that it is operatively connected to corresponding bearing elements on the press mold, such that the press mold is uniformly supported and is not deformed.

A blank can be designed as a container, in particular as a bottle, bowl, cup, (coffee) capsule, tray or can. Furthermore, it is possible to produce closures for containers using the method and the device according to the invention.

The press mold and the method for reducing the water content in a wet fiber-based blank and a corresponding device are explained with the aid of schematic figures. In the figures:

FIG. 1: shows a device with a press mold before exposure to microwaves;

FIG. 2: shows the device according to FIG. 1 during exposure to microwaves;

FIG. 3: is a perspective view of a press mold in an alternative device;

FIG. 4: is a sectional view through a press mold;

FIG. 5: is a perspective view of an alternative press mold;

FIG. 6: is a perspective view of an alternative press mold;

FIG. 7: is a perspective view of an alternative press mold;

FIG. 8: shows, by way of example, further typical fiber-based containers which can be produced by means of the method according to the invention;

FIG. 9 shows an example of a typical fiber-based closure that can be produced by means of the method according to the invention.

FIG. 1 shows a device 200 for reducing the water content in a fiber-based blank before exposure to microwaves. The fiber-based blank is in the present case a container 100 in the form of a bottle.

The device 200 has a microwave chamber 40 which is closed with a cover 41. In the cover 41 there is an exhaust air 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 floor 43. A plurality of openings 44 are arranged in the floor, through which openings supply air can be introduced into the microwave chamber 40. The device 200 also has a device 50 for generating microwaves. In the present case, this 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.

In the device 200, a press mold 20 is arranged within the microwave chamber 40. A wet fiber-based container 100 is arranged within the press mold 20. This was removed from a casting mold before being introduced into the press mold 20 and currently has a water content of approximately 75%. After the wet fiber-based container 100 was inserted into the press mold 20, an expandable tool 30 was inserted into the interior of the wet fiber-based container 100. By expanding the expandable tool 30, the wall of the container 100 is pressed onto the inner wall of the press mold 20 and the water or moisture in the wet fiber-based container 100 is partially pressed out of it. For this purpose, the press mold 20 is designed to be permeable to water. Water permeability can be achieved with a porosity; in the present case, individual channels or openings in the form of a gap are provided in the press mold. The water can thus be drained through gaps or openings at the parting point of the press mold. The escaping water, or rather the escaping moisture, is represented in a stylized manner by water droplets in the illustration according to FIG. 1. These water droplets can drip onto the floor 43 of the microwave chamber and be discharged through the openings 44. After this step, the fiber-based container 100 has a water content of approximately 50%.

FIG. 2 shows the device according to FIG. 1 during the exposure of the wet fiber-based container 100 to microwaves. FIG. 2 shows the actual drying process. In the device 50 for generating microwaves, microwaves, which are introduced into the microwave chamber 40 through the waveguide 51, are generated accordingly. The microwaves heat up the moisture in the fiber-based container 100, in other words, the molecules start to vibrate. The moisture begins to evaporate and exits the container 100 through the microwave-permeable mold 20. In FIG. 2, the expandable tool 30 is shown in the non-expanded state, but it is possible for the expandable tool 30 to remain expanded during the process shown here. The moisture, illustrated here in stylized form by wavy lines, enters the microwave chamber 40. To prevent this moisture from condensing in the microwave chamber 40, air is blown in through the openings 44 in the floor 43 of the microwave chamber 40. This blown-in air flows out of the microwave chamber 40 through the exhaust air opening 42. This creates inside the microwave chamber 40 a flow through which the moisture can be removed from the microwave chamber 40.

If the press mold is provided with a moisture-discharging channel into which the gap opens, the moisture does not escape from the press mold 20 and into the microwave chamber 40 as illustrated, but is collected in the moisture-discharging channel. Accordingly, the moisture can be discharged directly from the press mold 20 to the outside of the microwave chamber 40. Such designs are explained below.

In the present case, a holding device for the microwave-permeable press mold 20 is designed as an integral part of the cover 41. However, it is also conceivable that, for example, the device 200 is formed in two parts, i.e. consists of two halves and, if necessary, of a separate floor. For example, the press mold 20 can be held and pressed together by corresponding elements on the respective halves of the device 200. A corresponding design is shown in FIG. 3.

FIG. 3 shows a perspective view of a press mold 20 in an alternative device 200. A press mold 20 is arranged within the device 200. In the present case, the press mold 20 is formed in three parts. Shown is a first half of the press mold 20A which is connected at a mold parting line T to a second half of the press mold 20B (see FIG. 4), which is not shown here. In the lower region of the press mold 20, a floor part 24 is arranged which has a mold parting line in relation to both press mold halves 20A and 20B of the press mold 20.

The device 200 has, as in FIG. 1, a microwave chamber 40 which is closed with a cover 41. The upper end of the press mold 20 extends through the cover 41. The floor 24 of the press mold 20 also forms the bottom end of the microwave chamber 40. The floor part 24 merges into a microwave-tight tube 25. FIG. 3 shows the mold parting line on the press mold half 20A with a moisture-discharging channel 22 arranged therein, which opens into a gap 21 (see FIG. 4) not indicated in more detail here.

A plurality of openings 23 open into the moisture-discharging channel 22, through which openings the moisture collected in the channel 22 can be discharged. Alternatively, the channel 22 can also be pressurized through these openings 23.

In the region of the mold parting line between the floor 24 and the press mold halves 20A and 20B, openings 23 in the floor 24 are also visible. The openings 23 also open into a moisture-discharging channel 22 which is arranged in the region of the mold parting line between the floor part 24 and the press mold halves 20A and 20B in the floor part 24. The channel 22 is arranged circumferentially in the floor part 24. Likewise, the channel 22 in the press mold half 20A is designed to run along the entire mold parting line and opens into a corresponding gap.

Moisture can also be discharged through the openings 23 in the floor 24 and/or the channel 22 can be pressurized.

FIG. 4 shows a detail of a sectional view through the press mold 20 of FIG. 3. The sectional view extends parallel to the mold parting line between the floor 24 and the press mold halves 20A and 20B (see FIG. 3). The figure shows and illustrates the two press mold halves 20A and 20B which lie against each other along the mold parting line T. It can be seen that the two press mold halves 20A and 20B form a cavity for receiving a corresponding blank. It can be seen that a gap 21 is formed at the mold parting line in the region of the cavity, which gap opens into a moisture-discharging channel 22 in the direction into the press mold 20, i.e. into a wall of the press mold 20. Both the gap 21 and the channel 22 are formed in half in each of the press mold halves 20A and 20B. In other words, the inside of the press mold, i.e. the cavity, is connected to the channel 22 in a radially outward direction through the gap 21. In the closed state, the press mold halves 20A and 20B lie close to one another in the same direction behind the channel 22.

FIGS. 5, 6 and 7 each show a perspective view of an alternative press mold 20. All press molds 20 have two press mold halves 20A and 20B (not shown) and a floor 24. In all embodiments, the floor 24 opens into a microwave-tight tube 25. The floor 24 is identical to the floor 24 described in FIG. 3. In the embodiment according to FIG. 5, the moisture-discharging channel 22 in the press mold half 20A has no further openings. In the embodiment according to FIG. 6, the moisture-discharging channel 22 has openings 23 in an upper region. These correspond to the openings 23 described in FIG. 3. The embodiment according to FIG. 6 corresponds to that according to FIG. 3. The embodiment according to FIG. 7 corresponds to the embodiment according to FIG. 5 with respect to the moisture-discharging channel 22. Therefore, no further openings are provided in channel 22. In contrast, in an upper region of the press mold 20, in the present case in a neck region, additional gaps 21 are provided which open directly into the cavity of the press mold 20. However, these are arranged in a region of the press mold that corresponds to a region of the blank that is cut off from the blank after the water content has been reduced. It is understood that the embodiment according to FIG. 7 can also be combined with the embodiment according to FIG. 6.

FIG. 8 shows examples of other typical fiber-based containers that can be produced using the method described here. For instance, a container 100 is visible which corresponds to the container 100 from the description of FIGS. 1 and 2. This container 100 is also in the shape of a bottle and also has a thread on the bottle neck. The container 100′ is in the shape of a bowl; the container 100″ is in the shape of a cup.

FIG. 9 shows an example of a typical fiber-based closure 300 that can be produced using the method described herein.