Mold unit for drying a wet molded container body and method for drying such a container body

Abstract

The mold unit (1) comprises a mold body (2) having an inner wall section (4) defining a molding cavity (6) for receiving the container body. The mold body (2) defines channels (10) for evacuating water and / or steam out of the molding cavity (6) during drying of the container body. The molding cavity (6) extends along and about a longitudinal axis (X) between a top end (6.1) and a bottom end (6.2). The molding cavity (6) has, at least in one cross-sectional plane comprising the longitudinal axis (X), an outer contour (6.4) configured such that a lateral portion (6.6) of the outer contour (6.4) extends between the top end (6.1) and the bottom end (6.2), wherein the lateral portion (6.6) is configured such that the distance of the outer contour (6.4) to the longitudinal axis (X) varies along the longitudinal axis (X). The channels (10) are distributed about the longitudinal axis (X). In a cross-sectional plane, a or the channel(s) extend(s) non-linearly to follow at least the lateral portion (6.6).

Description

[0001] ALPLA Werke Alwin Lehner GmbH & Co KG P62914 / WO

[0002] 1

[0003] MOLD UNIT FOR DRYING A WET MOLDED CONTAINER BODY AND METHOD FOR DRYING SUCH A CONTAINER BODY

[0004] 1. Field of the invention The present invention is directed to a mold unit for drying a container body manufactured by wet molding a material, preferably a fiber-based material. The invention is also directed to a method for drying such a container body.

[0005] 2. Technical background There is a general trend to manufacture containers out of a fiber-based material, for example paper bottles. The fiber-based material can be wet-molded to be compressed into a shape nearing the desired bottle shape. After the wet molding step, the wet-molded product can be received in a molding cavity of a mold unit, dried up, and further shaped into the desired bottle shape. Reaching a suitable compression of the fibers and achieving a smooth drying of a fiber-based container are known to represent demanding challenges in a wet molding process. For the drying step, the mold unit usually has channels through which air can flow to allow evacuating of water out of the molding cavity. The channels extend about the molding cavity and along parallel, vertical lines that run throughout the mold unit. The channels may be formed i) by proximal walls that are curved to extend near the molding cavity and ii) by distal walls that remain linear. Thus, the sections of the channels become larger around the narrower parts of the container body, for example the neck portion of a bottle, than around wider parts of the container body, for example the main part of the bottle.

[0006] However, it has been observed that the fiber-based material forming the container body happens to have a relatively low resistance to thermo-mechanical stresses, in particular in the neck and / or shoulder portions of bottles. It is herein conjectured that this low resistance might be due to an uneven drying in various of the container body, for example in the neck and / or shoulder portions, which could stem from the fact that the sections of the channels vary and become larger around the narrow parts (neck portion) than around the wide parts (main portion). This variation in the channel sections might be generating pressure drops, which can in turn alter the velocity and direction of the flows of water or steam that need to be evacuated out of the mold unit to dry up the bottle. Such varying flows of water or steam in the channels might even re-wet transiently some parts of the container body, say the neck and / or shoulder portion of the bottle, and thus delay the completion of the drying step. ALPLA Werke Alwin Lehner GmbH & Co KG P62914 / WO

[0007] 2

[0008] 3. Summary

[0009] It is an object of the present disclosure to provide a mold unit that contributes to obviating or at least alleviating some or all of the afore-mentioned problems, in particular by improving the resistance to thermo-mechanical stresses. An aspect of the present disclosure provides a mold unit for drying a container body manufactured by wet molding a material, preferably a fiber-based material, the mold unit comprising a mold body having an inner wall section defining a molding cavity for receiving the container body, wherein the mold body defines a plurality of channels configured for evacuating water and / or steam that can flow out of the molding cavity during drying of the container body received in the molding cavity, wherein the molding cavity extends along and about a longitudinal axis between a top end and a bottom end, wherein the molding cavity has, at least in one cross-sectional plane comprising the longitudinal axis, an outer contour configured such that a lateral portion of the outer contour extends between the top end and the bottom end, wherein the lateral portion is configured such that the distance of the outer contour to the longitudinal axis varies along the longitudinal axis, and wherein the channels are distributed about the longitudinal axis, and wherein, in the at least one cross-sectional plane, at least one of the channels extends non-linearly so as to follow at least the lateral portion.

[0010] Thus, the shape of each one of the channels can be conformal to the outer contour, hence to the shape of the container body received in the molding cavity, by contrast to known channels that have variable sections because their distal walls extend along straight lines while their proximal walls can be bent along the neck-forming region of the molding cavity. As a result, the fluid for evacuating water and / or steam can flow within a respective channel with relatively constant velocity, direction, and pressure drop. This prevents or reduces transient re-wetting, for example in the neck and / or shoulder portion of a bottle. An improved resistance to thermo-mechanical stresses can ensue. Said distance between the longitudinal axis and the outer contour of the molding cavity may be measured in a direction perpendicular to the longitudinal axis.

[0011] As the channels are defined within a solid part, they shall be arranged outside the molding cavity. Preferably, the channels may extend generally vertically when the mold unit is in a manufacturing configuration in which drying of the container body can be ALPLA Werke Alwin Lehner GmbH & Co KG P62914 / WO

[0012] 3 operated. In the manufacturing configuration, the top end of the molding cavity lies above the bottom end of the molding cavity.

[0013] The top end of the molding cavity may be located near the upstream ends of the channels or, alternatively, near the downstream ends of the channels. Conversely, the bottom end of the molding cavity may be located near the downstream ends of the channels or, alternatively, near the upstream ends of the channels. The terms “top”, “bottom”, “upper”, “lower” and their derivatives may be read herein as referring to the manufacturing configuration in which drying of the container body can be operated.

[0014] The container body may have any shape defining a hollow volume, for example the shape of a bottle body. When the container body has the shape of a bottle body, the neck portion may correspond either to the top end or to the bottom end, depending on the orientation chosen for manufacturing the container body.

[0015] In some embodiments, the upstream end and the downstream end of the channels can correspond respectively to the neck portion and the base portion. In alternative embodiments, the upstream end and the downstream end of the channels can correspond respectively to the base portion and the neck portion.

[0016] - According to an embodiment, in respective cross-sectional planes comprising the longitudinal axis, at least some or all of the channels may extend non-linearly so as to follow at least the lateral portion of the outer contour. Thus, several or all channels may contribute to a constant flow of the evacuating fluid, hence to an improved resistance to thermo-mechanical stresses.

[0017] Alternatively to this embodiment, only one or two channel(s) may thusly extend non- linearly so as to follow at least the lateral portion of the outer contour. The respective shapes of the channels maybe adapted to the shape of the container body. Preferably, the number of channels may be comprised between 12 and 24 (around the entire molding cavity). The number of channels can thus be commensurate to the size and shape of the molding cavity, and it depends on the size and shape desired for the container body. These minimal and maximal numbers of channels enable to strike a balance, for containers of common sizes and shapes, between i) an appropriate flowrate of evacuation fluid through the channels on the one hand, and ii) the minimum thickness of the intermediate ribs in between channels that is required to confer a sufficient mechanical strength to the mold body on the other hand.

[0018] - According to an embodiment, the channels may be evenly distributed about the longitudinal axis. ALPLA Werke Alwin Lehner GmbH & Co KG P62914 / WO

[0019] 4

[0020] Such a distribution of the channels can allow a uniform cooling of the molding cavity to evenly dry the container body. The distribution of the channels may herein be considered when the mold unit is in a closed configuration.

[0021] - According to an embodiment, each of the channels may extend through the mold body from a top axial side of the mold body to a bottom axial side of the mold body.

[0022] Thus, the channels can contribute to efficiently drying up and cooling down the container body all along the mold body.

[0023] In some embodiments, the channels may exit at opposite faces of the mold body. Alternatively, the channels may enter from an upper side of the mold body, then extend vertically to a lower side, where they may exit to an outer side again.

[0024] - According to an embodiment, each of the channels may extend along a respective extension axis, and each of the channels may be designed such that its cross-sectional area, measured in a plane perpendicular to the extension axis, is substantially constant along most of, preferably along the whole of, its extension. Thus, the flow of the fluid for evacuating water and / or steam can be substantially constant along each channel, which prevents or reduces transient re-wetting and thus helps increase the resistance of the dried-up container body.

[0025] - According to an implementation of the preceding embodiment, for some or all of the channels a ratio of the minimum cross-sectional area Amin of a respective channel over the maximum cross-sectional area Amax of said respective channel may be in a range of

[0026] 1 < Amax / Amin < 1,5.

[0027] Thus, the flow of the fluid for evacuating water and / or steam can be constant or almost constant along each channel.

[0028] - According to an embodiment, the mold unit may further comprise an inflatable core selectively insertable into the molding cavity, particularly inside the container body being received in the molding cavity, wherein the inflatable core is configured to expand towards the inner wall section in order to press the container body against the inner wall section.

[0029] Thus, such inflatable core can press the container body against the wall of the molding cavity, and thus squeeze water out of it.

[0030] - According to an embodiment, the mold unit may further comprise a fluid delivering unit configured to deliver a fluid, preferably a gas, for example air, out of the channels, so as to support evacuation of steam and / or water out of the mold unit.

[0031] Thus, the fluid delivering unit can make the evacuating fluid circulate through the channels along with water and / or steam to be evacuated out of the mold unit. ALPLA Werke Alwin Lehner GmbH & Co KG P62914 / WO

[0032] 5

[0033] - According to an embodiment, the mold unit may further comprise a heating unit, preferably a microwave heater, for heating the container body received in the molding cavity.

[0034] Thus, the heating unit can heat part or all of the inner wall section so as to dry up the container body by evaporating water therefrom.

[0035] - According to an embodiment, each of the channels maybe designed such that the cross- sectional areas of two randomly selected channels, measured in a plane perpendicular to the respective extension axes, are substantially equal in any plane perpendicular to the longitudinal axis. Thus, each of the channels can have almost the same cross-sectional area as any other one of the channels. The flows of the fluid for evacuating water and / or steam can be substantially equal among the channels, for example where the neck and shoulder portions are formed. This contributes to an efficient evacuation of water and / or steam out of the mold unit. In the present disclosure, two physical quantities may be viewed as being “substantially equal” when their ratio is comprised between 0,80 and 1,25, preferably between 0,95 and 1,05.

[0036] - According to an implementation of the preceding embodiment, the cross-sectional areas of said two randomly selected channels may have a ratio comprised between 0,75 and 1,25, preferably between 0,85 and 1,15, more preferably between 0,95 and 1,05.

[0037] Thus, each of the channels has the same cross-sectional area as any other one of the channels. This contributes to a highly efficient evacuation of water and / or steam out of the mold unit.

[0038] - According to an embodiment, the outer contour may define, preferably along the longitudinal axis, a neck region, a base region, and a main region arranged between the neck region and the base region, so as to conform respectively to a neck portion, a base portion, and a main portion of the container body.

[0039] Preferably, the outer contour may further define a shoulder region arranged between the neck region and the main region. Preferably, the portions of the channels that extend along the main portion of the container body, say of the bottle body, may extend substantially parallel to the longitudinal axis. Thus, the path for evacuating water and / or steam can have the shortest possible length.

[0040] Preferably, all of the channels have substantially the same cross-sectional area when measured in a plane perpendicular to the longitudinal axis in the neck region, and / or ALPLA Werke Alwin Lehner GmbH & Co KG P62914 / WO

[0041] 6 wherein all of the channels have substantially the same cross-sectional area when measured in a plane perpendicular to the longitudinal axis in the main region, and / or wherein all of the channels have substantially the same cross-sectional area when measured in a plane perpendicular to the longitudinal axis in the base region. As each one of the channels has about the same cross-sectional area as any other one of the channels in the neck, main, shoulder and / or base region(s), the flow of the evacuating fluid (air) can be similar or equal from one channel to the other, thus contributing to an efficient evacuation of water and / or steam.

[0042] In some embodiments, the channels may be designed such that i) the sum of the cross- sectional areas of all of the channels measured in a plane perpendicular to the longitudinal axis in the neck region is substantially equal to ii) the sum of the cross- sectional areas of all of the channels measured in a plane perpendicular to the longitudinal axis in the base region.

[0043] Thus, the cumulative flowrate of the evacuating fluid (air) at the top end can be substantially equal to the cumulative flowrate of the evacuating fluid at the bottom end.

[0044] This can yield a regular, stable evacuation of water and / or steam during the drying step.

[0045] In other words, in a preferred implementation of the preceding embodiment, two sums of the cross-sectional areas of all of the channels in two planes randomly selected orthogonally to the longitudinal axis are substantially equal. Thus, the sum of the cross- sectional areas of all of the channels may be substantially constant along the longitudinal axis. This allows the flowrate to be relatively stable all along the molding cavity, which can in turn enable an efficient evacuation of water and / or steam during the drying step.

[0046] - In some embodiments, most, preferably all, of the channels may have substantially the shape of an annular segment in a cross-section perpendicular to their respective extension axis, in particular in the neck region and / or in the shoulder region and / or in the main region and / or in the base region of the container body.

[0047] In other words, the channels are distributed substantially in a tubular volume at least in the main region of the container body. This contributes to uniformly distributing the flow of evacuating air around the molding cavity. In a preferred implementation, some, most or all of the channels may have substantially the same size and shape in a cross-section perpendicular to the longitudinal axis, in particular in the neck region and / or in the shoulder region and / or in the main region and / or in the base region of the outer contour. Nevertheless, a few channels may have different sizes and shapes with respect to the rest of the channels in a cross -section perpendicular to the longitudinal axis in the neck region and / or in the main region and / or in the base region. ALPLA Werke Alwin Lehner GmbH & Co KG P62914 / WO

[0048] 7

[0049] - According to an embodiment, the at least one channel, preferably each of the channels, may be curved and / or angled along at least part of its extension axis to extend non- linearly so as to follow at least the lateral portion of the outer contour.

[0050] Thus, the or each non-linear channel can be conformal with a lateral outer contour of the molding cavity, hence of the container body, for example be a bottle.

[0051] The curved part of the at least one channel may follow one or more curvatures. Preferably, each curved part may have substantially a C-shaped curvature. Likewise, the angled part of the at least one channel may follow one or more angular segments.

[0052] In some embodiments, when the mold unit is in a closed, manufacturing configuration, the molding cavity may have a symmetry of revolution around the longitudinal axis. Thus, the container body, e.g. a bottle body, can have a round and symmetric shape.

[0053] Preferably, each channel of the plurality of channels is curved and / or angled substantially alongside the neck region, hence parallel to a curvature of the neck region. Thus, the or each curved channel can be conformal with a lateral portion of the outer contour. Preferably, each channel of the plurality of channels has substantially a C- shaped curvature.

[0054] - According to an embodiment, the mold body may have porous walls configured to drain water and / or steam out of the molding cavity into the channels to help evacuate the water and / or steam from the mold unit, the porous walls being preferably made out of a 3D- printed material.

[0055] Thus, the porous walls allow an efficient evacuation of water and / or steam to dry up and cool down the container body.

[0056] Preferably, the mold body may be composed of a first mold body part and a second mold body part, such that the mold body can be placed: - in a closed configuration in which the molding cavity is formed by juxtaposition of the first mold body part and the second mold body part, and

[0057] - in an open configuration in which the mold body is open and the first mold body part is distant, hence disconnected, from the second mold body part.

[0058] Thus, in the closed configuration, the molding cavity is defined as a union of at least two separable parts. The mold body may be maneuverable to be placed selectively in the open configuration or in the closed configuration. The closed configuration corresponds to the manufacturing configuration.

[0059] In some embodiments, a distance separating any one of the channels and the molding cavity may be smaller than 3.0 mm and larger than 0.5 mm, preferably larger than 1.0 mm . This distance depends on the size and shape desired for the container body. ALPLA Werke Alwin Lehner GmbH & Co KG P62914 / WO

[0060] 8

[0061] These minimal and maximal distances enable to strike a balance, for containers of common sizes and shapes, between i) a sufficient cooling and draining by the evacuation fluid through the channels on the one hand, and ii) the minimum thickness of the mold body walls required to confer a sufficient mechanical strength to the mold body on the other hand.

[0062] In some embodiments, a gap separating two consecutive channels of the plurality of channels around the longitudinal axis may be comprised between 1 mm and 3 mm. Thus, the evacuating air flowing through the channels can cool the mold unit efficiently and uniformly, which avoids generation of too large thermal stresses in between two consecutive channels.

[0063] Optionally, for a given mold unit and an average size of container body, the largest width or diameter of the molding cavity (e.g. in the main region), may be about 120-140 mm, and the smallest width or diameter of the molding cavity (e.g. in the neck region) may be about 30 mm. - Another aspect of the present disclosure provides a method for drying a container body manufactured by wet molding a material, preferably a fiber-based material, the method comprising:

[0064] - implementing a mold unit according to any one of the preceding claims,

[0065] - placing the container body to be dried in the molding cavity, - optionally placing an inflatable core inside the container body received in the molding cavity, and expanding the inflatable core to press the container body against the inner wall section, such that water flowing out of the molding cavity can be drained out of the mold unit via the channels,

[0066] - heating the container body received in the molding cavity, preferably by subjecting it to microwaves, such that steam flowing out of the molding cavity can be drained out of the mold unit via the channels,

[0067] - optionally, at least during heating of the container body, delivering a fluid, preferably a gas like air, through the channels to help evacuate the water and / or steam out of the mold unit via the channels, wherein the fluid is preferably delivered from an upper side to a lower side of the respective channel, wherein preferably the fluid is a cooling fluid so as to cool the mold body at least during heating the container body, and

[0068] - taking the dried container body out of the molding cavity.

[0069] In some embodiments, the fiber-based material may comprise or consist in pulp material, cellulose fibers such as cellulose fibers obtained from wood, and / or non-wood ALPLA Werke Alwin Lehner GmbH & Co KG P62914 / WO

[0070] 9 fibers, in particular hemp, straw, bagasse, bamboo and / or other agricultural fibers. In some embodiments, the fiber-based material may comprise a fiber content of at least 60% or at least 70% or at least 80% or at least 90% or at least 95%. Thus, such fiberbased materials can be suitably handled, wetted, deformed, and dried, while having an increased biodegradability and, possibly, recyclability.

[0071] The words “comprise”, “include”, “have” and their derivatives are to be interpreted inclusively rather than exclusively. The term “and / or” used in the context of “X and / or Y” should be interpreted as “X,” or “Y,” or “X and Y.” 4. Brief description of drawings

[0072] Further features, details and advantages of the present invention are described hereinafter, in particular in relation to the appended figures, which illustrate, schematically and not on scale, some of the afore-described aspects, embodiments and implementations thereof, and in which: Fig. 1 shows a cutaway perspective view of a half of a mold unit according to an embodiment of the present disclosure;

[0073] Fig. 2 shows a side view in plane II of Fig. 1;

[0074] Fig. 3 shows a partial cross-sectional view in plane III in Fig. 2;

[0075] Fig. 4 shows a flowchart of a method according to an embodiment of the present disclosure.

[0076] 5. Detailed description

[0077] Fig. 1 to 3 illustrate a mold unit 1 for drying a not shown container body that is manufactured by wet molding a fiber-based material, which may comprise cellulose fibers. The wet molding step of the manufacturing process may be performed previously in another, not shown mold unit, then the semi-finished container body may be transferred to the mold unit 1, where the drying step of the manufacturing process may be performed.

[0078] The mold unit 1 comprises a mold body 2, which has an inner wall section 4. The inner wall section 4 defines a molding cavity 6 for receiving the container body. The molding cavity 6 extends about a longitudinal axis X. The molding cavity 6 extends, along the longitudinal axis X, between a top end 6.1 and a bottom end 6.2.

[0079] Further, the mold body 2 defines a plurality of channels 10, which are configured for evacuating water and / or steam that can flow out of the molding cavity 6 during drying ALPLA Werke Alwin Lehner GmbH & Co KG P62914 / WO

[0080] 10 of the container body in the molding cavity 6. As visible on Fig. 3, the channels 10 are evenly distributed about the longitudinal axis X (closed mold unit 1), thus promoting a uniform cooling of the molding cavity to evenly dry the container body.

[0081] The mold unit 1 may further comprise a fluid delivering unit 7, which is configured to deliver a fluid, for example pressurized air, out of the channels 10, so as to support evacuation of steam and / or water out of the mold unit 1. The flows of evacuation air are materialized in Fig. 1 and 2 by arrows F.

[0082] Also, the mold unit 1 may comprise a heating unit 8, preferably a microwave heater, for heating the container body received in the molding cavity 6. The heating unit 8 can heat the inner wall section 4 so as to dry up the container body by evaporating water therefrom.

[0083] The mold body 2 may have not shown porous walls surrounding most or all of the inner wall section 4. The porous walls may be configured to drain water and / or steam out of the molding cavity into the channels to help evacuate the water and / or steam from the mold unit. In other words, the porous walls fluidly connect the molding cavity 6 to the channels 10. The porous walls may preferably be made out of a 3D-printed material. When the heating unit 8 is heating the inner wall section 4, the porous walls allow an efficient evacuation of water and / or steam to flow therethrough, hence out of the molding cavity 6, to efficiently dry up and cool down the container body. As visible on Fig. 3 there are about 18 channels defined by the mold body 2. In particular, the number of channels may be adapted to various parameters, for example the type of material that is being molded, the size of the container body, the time of drying and / or cooling the molding cavity 6 etc.

[0084] The channels 10 may extend generally vertically when the mold unit 1 is in a manufacturing configuration in which drying of the container body can be operated. In the manufacturing configuration, the top end 6.1 of the molding cavity 6 lies above the bottom end 6.2 of the molding cavity 6.

[0085] Every channel 10 may have an upstream end 10.1 and a downstream end 10.2, defined by the orientation of the flows through the channel 10. The upstream end 10.1 of a respective channel 10 may be located near the top end 6.1 of the molding cavity 6.

[0086] Conversely, the downstream end 10.2 of a respective channel 10 maybe located near the bottom end 6.2 of the molding cavity 6.

[0087] The molding cavity 6 has an outer contour 6.4 that is configured such that a lateral portion 6.6 of the outer contour 6.4 extends between the top end 6.1 and the bottom end 6.2, herein not only in the plane of Fig. 2 but also in several other cross-sectional planes comprising the longitudinal axis X. The lateral portion 6.6 of the outer contour 6.4 is ALPLA Werke Alwin Lehner GmbH & Co KG P62914 / WO

[0088] 11 configured such that the distance D6-X from the outer contour 6.4 to the longitudinal axis X varies along the longitudinal axis X, when measured in a direction perpendicular to the longitudinal axis X, e.g. in a direction perpendicular to the plane of Fig. 2. In other words, the molding cavity may have a curved shape. In the example of Fig. 1 to 3, the outer contour 6.4 is designed to manufacture a container body that is in the form of a bottle body. Nevertheless, the container body may have any shape defining a hollow volume. The outer contour 6.4 may define a neck region, a shoulder region, a base region, and a main region arranged between the neck region and the base region, so as to conform respectively to a neck portion, a shoulder portion, a base portion, and a main portion of the bottle body, from top end 6.1 to bottom end 6.2 along the longitudinal axis X, a neck portion, a main portion and a base portion. The shoulder portion may be joining the neck portion to the main portion, and the main portion may be joining the shoulder portion and the base portion.

[0089] The container body, e.g. bottle body, can have a round and symmetric shape when the molding cavity 6 has a symmetry of revolution around the longitudinal axis X (closed mold unit 1), as is the case in Fig. 1 to 3. In the example of Fig. 1 to 3, the upstream end 10.1 and the downstream end 10.2 of a channel 10 can be located respectively at the neck portion and at the base portion of the bottle body.

[0090] In a respective one of said cross-sectional planes, e.g. in the plane of Fig. 2, every channel 10 extends non-linearly to follow the lateral portion 6.6 of the outer contour 6.4. Every channel 10 may be curved and / or angled alongside the lateral portion 6.6, such that all of the channels 10 may extend non-linearly so as to follow at least the lateral portion 6.6 of the outer contour 6.4. In particular, every channel 10 may be curved with a C-shaped curvature substantially alongside the neck region so as to be conformal with a lateral portion of the outer contour 6.4.

[0091] In the not shown case where the container body is not cylindrical but rather prismatic, for example with a rectangular basis, some of the channels only may be non-linear to follow the lateral portion of the outer contour, while other channels maybe linear also to follow the lateral portion in a region where it is linear. Thanks to the non-linear extension of channels 10, the shape of every channel 10 can be conformal to the outer contour 6.6, hence to the shape of the container body received in the molding cavity 6. Both the proximal wall 10.3 and the distal wall 10.4 of every channel 10 may extend non-linearly and thus follow the lateral portion 6.6. When drying up the container body, the air F for evacuating water and / or steam can flow within every ALPLA Werke Alwin Lehner GmbH & Co KG P62914 / WO

[0092] 12 channel 10 with a relatively constant velocity, direction, and pressure drop, which can improve resistance to thermo-mechanical stresses, as detailed above.

[0093] By contrast, in some known mold units, channels have variable sections because their distal walls extend along straight lines, typically parallel to the longitudinal axis, throughout the mold unit, while their proximal walls can be bent along the neck-forming region of the molding cavity. The sections of such channels become larger around the neck portion of the bottle body than around the main part of the bottle body, which can result in a relatively low efficiency and thermo-mechanical resistance, as detailed above.

[0094] Every channel 10 may extend through the mold body 2 from a top axial side 2.1 of the mold body 2 to a bottom axial side 2.2 of the mold body 2. Thus, the channels 10 can along the entire mold body 2. As visible in Fig. 1 and 2, the channels 10 may exit at opposite faces of the mold body 2.

[0095] Every channel 10 may extend along a respective extension axis X10 (Fig. 2), which may follow essentially the lateral portion 6.6. Every channel 10 may be designed such that its cross-sectional area, measured in a plane perpendicular to the extension axis X10 (e.g. a plane perpendicular to the plane of Fig. 2), is substantially constant along the whole of the extension of the respective channel 10. The portions of the channels 10 that extend along the main portion of the container body may extend substantially parallel to the longitudinal axis X, herein along a straight segment. A ratio of the minimum cross-sectional area Amin of a respective channel 10 over the maximum cross-sectional area Amax of said respective channel 10 may be in a range of 1 < Amax / Amin < 1,5, for example equal to about 1,25. Thus, the channel 10 can have mostly the same cross-sectional area along its extension axis X10, which allows the flow of evacuating air F to be substantially constant along said channel 10. Every channel 10 may be designed such that the cross-sectional areas of two randomly selected channels 10 (e.g. the ones visible in Fig. 2), measured in a plane perpendicular to the respective extension axes X10 (e.g. a plane perpendicular to the plane of Fig. 2), are substantially equal in any plane perpendicular to the longitudinal axis X (e.g. a plane perpendicular to the plane of Fig. 2). More particularly, the cross-sectional areas of said two randomly selected channels 10, e.g. the ones visible in Fig. 2, may have a ratio comprised of about 1. As every channel 10 can have the same cross-sectional area as any other one of the channels 10, the flows F of air for evacuating water and / or steam can be substantially equal among the channels, for example where the neck and shoulder portions are formed. The channels 10 may be designed such that i) the sum of the cross-sectional areas of all of the channels 10, measured in a plane perpendicular to the longitudinal axis X (e.g. a ALPLA Werke Alwin Lehner GmbH & Co KG P62914 / WO

[0096] 13 plane perpendicular to the plane of Fig. 2), in the neck region is substantially equal to ii) the sum of the cross-sectional areas of all of the channels 10. Thus, the cumulative flowrate of the evacuating air at the top end 6.1 can be substantially equal to the cumulative flowrate of the evacuating air at the bottom end 6.2. The flowrate of evacuating air can be relatively stable all along the molding cavity 6.

[0097] As shown in Fig. 3, every channel 10 may have substantially the shape of an annular segment in a cross-section perpendicular to their respective extension axis X10. In other words, the channels 10 are distributed substantially in a tubular volume. This contributes to uniformly distributing the flow F of evacuating air around the molding cavity 10. All of the channels 10 may have substantially the same size and shape in a cross-section perpendicular to the longitudinal axis X, in particular in the neck region and / or in the shoulder region and / or in the main region and / or in the base region of the outer contour.

[0098] A distance D10-6 (Fig. 1) separating any one of the channels 10 and the molding cavity 6 may be smaller than 3 mm and larger than 0.5 mm, preferably larger than 1.0 mm. In the largest region of the molding cavity 6, herein in the main region, a gap G10-10 (Fig. 2) separating two consecutive channels 10 around the longitudinal axis X may be comprised between 1 mm and 3 mm. A thusly selected gap G10-10 enables to strike a balance, for containers of common sizes and shapes, between i) an appropriate number and size of channels on the one hand, and ii) the minimum thickness of the intermediate ribs required to confer a sufficient mechanical strength to the mold body on the other hand

[0099] The mold body 2 may be composed of a first mold body part and a second mold body part (not shown), such that the mold body can be placed:

[0100] - in a closed, manufacturing configuration in which the molding cavity 6 is formed by juxtaposition of the first mold body part and the second mold body part, and - in an open configuration in which the mold body 2 is open and the first mold body part is distant, hence disconnected, from the second mold body part.

[0101] The mold body 2 maybe maneuverable to be placed selectively in the open configuration or in the closed configuration.

[0102] Fig. 4 illustrates a method 101 for drying the container body, which maybe manufactured using the mold unit 1 of Fig. 1 to 3, by wet molding a fiber-based material. The method

[0103] 101 comprising:

[0104] - 102) implementing the mold unit 1,

[0105] - 104) placing the container body to be dried in the molding cavity 6,

[0106] - 106) optionally placing a not shown inflatable core inside the container body received in the molding cavity 6, and expanding the inflatable core to press the ALPLA Werke Alwin Lehner GmbH & Co KG P62914 / WO

[0107] 14 container body against the inner wall section 4, such that water flowing out of the molding cavity can be drained out of the mold unit 1 via the channels,

[0108] - 108) heating the container body received in the molding cavity 6, preferably by subjecting it to microwaves emitted by the heating unit 8, such that steam flowing out of the molding cavity can be drained out of the mold unit 1 via the channels 10,

[0109] - 101) optionally, at least during heating of the container body, delivering a fluid, preferably a gas like air, through the channels 10 to help evacuate the water and / or steam out of the mold unit 1 via the channels 10, wherein the fluid is preferably delivered from an upper side to a lower side of the respective channel 10, wherein preferably the fluid is a cooling fluid so as to cool the mold body 2 at least during heating the container body, and

[0110] - 112) taking the dried container body out of the molding cavity 6.

[0111] The steps 106 and 108 may be performed in two consecutive mold units, resp. molding cavities: a not shown first mold unit dedicated to wet molding and pressing water out of the molding cavity, and the mold unit 1 as the second unit dedicated to heating the container body and evacuating steam out of the mold unit 6 via the channels 10.

[0112] The invention defined in the appended claims is not limited to the afore-described objects, aspects, embodiments and implementations, most of which maybe combined.

Claims

ALPLA Werke Alwin Lehner GmbH & Co KG P62914 / WO15Claims1. Mold unit (1) for drying a container body manufactured by wet molding a material, preferably a fiber-based material, the mold unit (1) comprising a mold body (2) having an inner wall section (4) defining a molding cavity (6) for receiving the container body, wherein the mold body (2) defines a plurality of channels (10) configured for evacuating water and / or steam that can flow out of the molding cavity (6) during drying of the container body received in the molding cavity (6), wherein the molding cavity (6) extends along and about a longitudinal axis (X) between a top end (6.1) and a bottom end (6.2), wherein the molding cavity (6) has, at least in one cross-sectional plane comprising the longitudinal axis (X), an outer contour (6.4) configured such that a lateral portion (6.6) of the outer contour (6.4) extends between the top end (6.1) and the bottom end (6.2), wherein the lateral portion (6.6) is configured such that the distance (D6-X) of the outer contour (6.4) to the longitudinal axis (X) varies along the longitudinal axis (X), and wherein the channels (10) are distributed about the longitudinal axis (X), and wherein, in the at least one cross-sectional plane, at least one of the channels (10) extends non-linearly so as to follow at least the lateral portion (6.6).

2. Mold unit (1) according to claim 1, wherein, in respective cross-sectional planes comprising the longitudinal axis (X), at least some or all of the channels (10) extend non-linearly so as to follow at least the lateral portion (6.6) of the outer contour (6-4)-3. Mold unit (1) according to any one of the preceding claims, wherein the channels (10) are evenly distributed about the longitudinal axis (X).

4. Mold unit (1) according to any one of the preceding claims, wherein each of the channels (10) extends through the mold body (2) from a top axial side (2.1) of the mold body (2) to a bottom axial side (2.2) of the mold body (2).ALPLA Werke Alwin Lehner GmbH & Co KG P62914 / WO165. Mold unit (1) according to any one of the preceding claims, wherein each of the channels (10) extends along a respective extension axis (X10), and wherein each of the channels (10) is designed such that its cross-sectional area, measured in a plane perpendicular to the extension axis (X10), is substantially constant along most of, preferably along the whole of, its extension.

6. Mold unit (1) according to claim 5, wherein, for some or all of the channels (10) a ratio of the minimum cross-sectional area Amin of a respective channel over the maximum cross-sectional area Amax of said respective channel is in a range of 1 < Amax / Amin < 1,5.

7. Mold unit (1) according to any one of the preceding claims, further comprising an inflatable core selectively insertable into the molding cavity (6), particularly inside the container body being received in the molding cavity (6), wherein the inflatable core is configured to expand towards the inner wall section (4) in order to press the container body against the inner wall section (4).

8. Mold unit (1) according to any one of the preceding claims, further comprising a fluid delivering unit (7) configured to deliver a fluid, preferably a gas, for example air, out of the channels (10), so as to support evacuation of steam and / or water out of the mold unit (1).

9. Mold unit (1) according to any one of the preceding claims, further comprising a heating unit (8), preferably a microwave heater, for heating the container body received in the molding cavity (6).

10. Mold unit (1) according any one of the preceding claims, wherein each of the channels (10) is designed such that the cross-sectional areas of two randomly selected channels (10), measured in a plane perpendicular to the respective extension axes (X10), are substantially equal in any plane perpendicular to the longitudinal axis (X).ALPLA Werke Alwin Lehner GmbH & Co KG P62914 / WO1711. Mold unit (1) according to claim 10, wherein the cross-sectional areas of said two randomly selected channels (10) have a ratio comprised between 0,75 and 1,25, preferably between 0,85 and 1,15, more preferably between 0,95 and 1,05.

12. Mold unit (1) according to any one of the preceding claims, wherein the outer contour (6.4) defines, preferably along the longitudinal axis (X), a neck region, a base region, and a main region arranged between the neck region and the base region, so as to conform respectively to a neck portion, a base portion, and a main portion of the container body.

13. Mold unit (1) according to any one of the preceding claims, wherein the at least one channel (10), preferably each of the channels (10), is curved and / or angled along at least part of its extension axis (X10) to extend non-linearly so as to follow at least the lateral portion (6.6) of the outer contour (6.4).

14. Mold unit (1) according to any one of the preceding claims, wherein the mold body (2) has porous walls configured to drain water and steam out of the molding cavity (6) into the channels (10) to help evacuate the water and / or steam from the mold unit (1), the porous walls being preferably made out of a 3D-printed material.

15. Method (101) for drying a container body manufactured by wet molding a material, preferably a fiber-based material, the method comprising:(102) implementing a mold unit (1) according to any one of the preceding claims,(104) placing the container body to be dried in the molding cavity (6),(106) optionally, placing an inflatable core inside the container body received in the molding cavity (6), and expanding the inflatable core to press the container body against the inner wall section, such that water flowing out of the molding cavity (6) can be drained out of the mold unit (1) via the channels (10),(108) heating the container body received in the molding cavity (6), preferably by subjecting it to micro waves, such that steam flowing out of the molding cavity (6) can be drained out of the mold unit (1) via the channels (10),(110) optionally, at least during heating of the container body, delivering a fluid, preferably a gas like air, through the channels (10) to help evacuate the waterALPLA Werke Alwin Lehner GmbH & Co KGP62914 / WO18 and / or steam out of the mold unit (1) via the channels (10), wherein the fluid is preferably delivered from an upper side to a lower side of the respective channel (10), wherein preferably the fluid is a cooling fluid so as to cool the mold body (2) at least during heating the container body, and - (112) taking the dried container body out of the molding cavity (6).

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