Expandable member for container molding

Abstract

An expandable member for use in molding a container in a cavity of a mold includes a neck portion and a body portion. The neck portion defines an opening of the expandable member and has a first width. The body portion has a second width different from the first width and has a wall having a thickness that varies along a length of the wall.

Description

Technical Field

[0001] The present invention relates to various methods and systems for forming molded containers from fiber suspensions, such as fiber suspensions containing pulp, and expandable members used in such methods and systems. The containers may form consumer packaging, such as bottles, for containing liquids, powders, other flowable materials, or solid objects. Background Art

[0002] There is a desire to reduce the use of plastic in consumer products, particularly packaging. Trays and other simple shapes are often made from paper pulp, but making more complex objects such as bottles is more difficult.

[0003] For example, it may be difficult to ensure that the pulp is compacted within the mold to form a bottle with sufficient wall thickness and strength. Summary of the invention

[0004] According to a first aspect of the present invention, there is provided an expandable member for use when molding a container in a cavity of a mold, the expandable member comprising: a neck portion defining an opening of the expandable member, the neck portion having a first width; and a main body portion having a second width different from the first width; wherein the main body portion comprises a wall having a wall thickness that varies along the length of the wall.

[0005] Because the main body portion has a wall whose thickness varies along the length of the wall, the expansion of the main body portion of the expandable member can be controlled. For example, the expansion of thinner areas of the wall can be preferentially increased over thicker areas of the wall. Thus, by varying the thickness of the wall of the main body portion, the contact of the main body portion with the container when the expandable member is expanded can be controlled. Such control of the contact can facilitate molding of the container.

[0006] In particular, the point of contact of the expandable member with the container may affect the subsequent expansion of the expandable member within the container due to friction. Therefore, by controlling which area of ​​the main body portion of the expandable member contacts the container first, the subsequent expansion and contact point of the expandable member can be controlled. This can ensure that the expandable member can contact a specific area of ​​the container with sufficient pressure to ensure sufficient compaction of the material from which the container is made. The expandable member can thus provide a container with a more uniform strength when compared to, for example, a container formed by using an expandable member with a main body portion of constant thickness.

[0007] Width as discussed herein may include the maximum width between two opposing points on the outer surface of the relevant portion of the expandable member. Width as discussed herein may include the width measured when the expandable member is supported with the opening exposed to the surrounding external atmosphere, e.g., in the absence of substantially radially inward or outward pressure applied to the expandable member.

[0008] Optionally, the thickness of the wall varies gradually along the length of the wall. This may provide more desirable expansion characteristics than, for example, a wall having one or more discrete or step changes in thickness along its length.

[0009] Optionally, the thickness of the wall varies continuously along the length of the wall, for example without a step change in thickness. Optionally, the thickness of the wall tapers along the length of the wall, for example along substantially the entire length of the wall.

[0010] Optionally, the main body portion includes a shoulder portion proximal to the neck portion and a lower portion distal to the neck portion, the shoulder portion having a first wall thickness, the lower portion having a second wall thickness greater than the first wall thickness. By having a relatively thin shoulder portion and a relatively thick lower portion, the contact of the main body of the expandable member with the container when the expandable member is expanded can be controlled so that the shoulder portion contacts the container before the lower portion. Friction can then lock the shoulder portion in place relative to the container, and the remainder of the main body portion of the expandable member is then expanded to fill the container and come into contact with it.

[0011] Optionally, the second wall thickness is between 1.2 and 2.0 times the first wall thickness. This ratio can provide the desired expansion characteristics of the expandable member while ensuring that the thickness of the main body portion does not vary too much. This can, for example, facilitate the manufacture of the expandable member.

[0012] Optionally, the second wall thickness is between 1.4 and 1.8 times the first wall thickness. Optionally, the second wall thickness is about 1.6 times the first wall thickness.

[0013] Optionally, the first wall thickness is about 1.2 mm to 4.0 mm. Optionally, the first wall thickness is about 1.5 mm to 3.0 mm. Optionally, the first wall thickness is about 2.7 mm.

[0014] Optionally, the second wall thickness is about 1.7 mm to 7.2 mm. Optionally, the second wall thickness is about 2.1 mm to 5.4 mm. Optionally, the second wall thickness is about 4.4 mm.

[0015] Optionally, the neck portion comprises another wall portion having another wall thickness greater than the maximum wall thickness of the wall of the main body portion. By having the neck portion have a relatively thicker further wall portion compared to the wall of the main body portion, increased strength may be provided in the region of the opening of the expandable member (e.g. in the region where the expandable member may be connected to an expansion fluid source when in use). The relatively thicker further wall portion of the neck portion compared to the wall of the main body portion may also promote expansion of the main body portion in preference to the neck portion. This may be beneficial when, for example, the main body portion has a width greater than the neck portion.

[0016] Optionally, the second width is greater than the first width. Optionally, the second width is the maximum width of the main body portion. Optionally, the width of the main body portion varies along its length. Optionally, the minimum width of the main body portion occurs adjacent to the neck portion. Optionally, the second width is away from the base portion, for example, closer to the neck portion than the base portion. Optionally, if present, the second width occurs at the interface between the shoulder portion and the lower portion. Optionally, the width of the shoulder portion increases between the neck portion and the lower portion.

[0017] Optionally, the second wall thickness is a maximum wall thickness of the body portion.

[0018] Optionally, the further wall thickness is between 1.1 and 1.5 times the second wall thickness. Optionally, the second wall thickness is about 1.2 times the first wall thickness.

[0019] Optionally, the further wall thickness is about 3.1 mm to 10.8 mm. Optionally, the second wall thickness is about 3.9 mm to 8.1 mm. Optionally, the first wall thickness is about 5.2 mm.

[0020] Optionally, the expandable member includes a base portion located at an end of the main body portion opposite the neck portion, the base portion including a third width, the third width being greater than the second width. By providing an expandable member having a base portion that is wider than the main body portion, the base portion may be more likely to be urged toward the periphery of the base of the container when the expandable member expands, when compared to, for example, an expandable member including a main body portion and a base portion having the same width. This may ensure that the expandable member can contact an area of ​​the periphery of the base of the container with sufficient pressure to ensure adequate compaction of the material from which the container is made.

[0021] With respect to expandable members including a body portion and a base portion having the same width, when in use, the expandable member may first contact the base of the container, thereby creating friction that hinders subsequent expansion of the expandable member toward the periphery of the base of the container. As a result, the periphery of the container may not be adequately compacted, and therefore, weak points may occur in the finished container. The interior and exterior surface finish of the container may also be unacceptably rough. Providing an expandable member having a base portion that is wider than the body portion can alleviate these factors.

[0022] Optionally, the difference between the third width and the first width is greater than a maximum thickness of a wall of the body portion.

[0023] Optionally, the third width is around 25 mm to 70 mm, for example around 40 mm to 55 mm.

[0024] Optionally, the third width is no more than 10% greater than the second width, no more than 5% greater than the second width, or no more than 1% greater than the second width.

[0025] Optionally, the second width is around 24 mm to 69 mm, for example around 39 mm to 54 mm.

[0026] Optionally, the second width is no more than 80% greater than the first width, no more than 70% greater than the first width, no more than 60% greater than the first width, or no more than 50% greater than the first width.

[0027] Optionally, the first width is around 23 mm to 68 mm, for example around 38 mm to 53 mm.

[0028] Optionally, the transition region between the main body portion and the base portion includes a region of reduced wall thickness relative to adjacent regions of the main body portion. This may urge the base portion to move towards the periphery of the base of the container. This may enable the base portion to move towards the periphery of the base of the container before adjacent regions of the main body portion come into contact and potentially become frictionally engaged with the container.

[0029] Optionally, the adjacent region of the main body portion is a region having a maximum thickness of the wall of the main body portion.Optionally, the adjacent region of the main body portion is a region of the main body portion within 5% of the total length of the main body portion of the transition region.

[0030] Optionally, the base portion is circular. Optionally, the base portion has the form of a spherical dome. This shape can push the base portion towards the periphery of the base of the container, for example in contrast to a base portion with a flat lower surface.

[0031] Optionally, the wall thickness of the base portion varies, and the minimum wall thickness of the base portion is located between the most distal portion of the base portion from the opening and the transition area between the main body portion and the base portion. This minimum wall thickness position can promote the base portion to expand toward the periphery of the container when the expandable member expands in use.

[0032] Optionally, the base portion comprises a wall having a wall thickness substantially corresponding to the maximum thickness of the main body portion. Optionally, the base portion comprises a wall having a wall thickness less than the maximum wall thickness of the main body portion.

[0033] Optionally, the third width is no more than 1.2 times the second width.This may urge the base portion to move toward the periphery of the base of the container when the expandable member expands, while avoiding a friction lock between the base portion and the base of the container.

[0034] Optionally, the expandable member comprises a single piece, such as having a body portion and a neck portion integrally formed.For example, the expandable member can comprise a single wall structure shaped to define the various portions of the expandable member described herein.

[0035] Optionally, the expandable member comprises or is made of an elastically deformable material. Optionally, the expandable member comprises or is made of a rubber material. Optionally, the expandable member comprises or is made of a silicone material.

[0036] Optionally, the expandable member is formed of a material having a Shore A durometer comprised between 20 and 50, such as about 40.

[0037] Optionally, the shapes and sizes of the expandable members discussed above include the shapes and sizes of the expandable members in a partially expanded configuration, for example in which sufficient fluid is contained within the hollow interior of the expandable member to allow the expandable member to have a definite shape without deforming the wall structure of the expandable member.

[0038] According to a second aspect of the present invention, there is provided a container moulding system comprising: a container mould comprising a mould cavity for receiving a component, wherein the component is a fibre suspension or a partially formed container; and an expandable member of the first aspect of the present invention, which is expandable in the mould cavity so as to drive the component against the inner surface of the mould cavity during the process of forming a container from the component.

[0039] Optionally, the container molding system includes an expansion fluid source fluidly connectable to the expandable member so that the expansion fluid can be selectively supplied to the interior of the expandable member when the expandable member is inserted into the mold cavity. Thus, the expandable member can expand when in use in the mold cavity to contact the fiber suspension or partially formed container held in the mold cavity and apply pressure to the fiber suspension or partially formed container.

[0040] Optionally, the container molding system comprises a heat source for supplying heat to the component while the component is held in the mold cavity.This system can thus be used to provide a thermoforming process on the component while the component is held in the mold cavity.

[0041] Optionally, the container molding system comprises a bottle molding system for molding bottles, for example from a fiber suspension.

[0042] Optionally, the container molding system is at least one of a fiber container molding system and a pulp container molding system.

[0043] According to a third aspect of the present invention, there is provided a method for molding a container, the method comprising: providing a component in a mold cavity of a mold, wherein the component is a fiber suspension or a partially formed container; providing an expandable member of the first aspect of the present invention in the mold cavity; and expanding the expandable member so that relatively thin regions of the wall of the main body portion expand before relatively thick regions of the wall of the main body portion, and so as to drive the component against the inner surface of the mold cavity during the process of forming the container from the component.

[0044] By expanding the expandable member so that relatively thin areas of the wall of the main body portion expand before relatively thick areas of the wall of the main body portion, the expansion of the main body portion of the expandable member can be controlled. For example, the expansion of thinner areas of the wall can be prioritized over thicker areas of the wall. Therefore, by varying the thickness of the wall of the main body portion, the contact of the main body portion with the container when the expandable member is expanded can be controlled. Such control of the contact can facilitate molding of the container.

[0045] In particular, the point of contact of the expandable member with the container may affect the subsequent expansion of the expandable member within the container due to friction. Therefore, by controlling which area of ​​the main body portion of the expandable member contacts the container first, the subsequent expansion and contact point of the expandable member can be controlled. This can ensure that the expandable member can contact a specific area of ​​the container with sufficient pressure to ensure sufficient compaction of the material from which the container is made. The method can thus provide a container with more uniform strength when compared to, for example, a method using an expandable member with a main body portion of constant thickness.

[0046] Optionally, the method comprises applying heat to the component in the mould cavity.This method can thus be used to provide a thermoforming process on the component while it is held in the mould cavity.

[0047] Optionally, the method is a method of molding at least one of a fiber container and a pulp container.

[0048] According to a fourth aspect of the present invention there is provided a container obtainable or obtained from a method of manufacture comprising the method of the third aspect of the present invention.

[0049] For example, the container may be obtainable or obtained from the method of the third aspect of the invention.

[0050] Optionally, the container is at least one of a fiber container and a pulp container.

[0051] The method of making may include at least one additional process. At least one additional process may include coating and drying the container to produce a coated container. At least one additional process may include applying a closure to the container or the coated container.

[0052] In some examples, the container is a bottle. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0054] Figure 1 is a schematic diagram of an example process for making a bottle from pulp;

[0055] Figure 2 is used for Figure 1 Schematic diagram of an example bladder during an example process;

[0056] Figure 3 yes Figure 2 Schematic diagram of an example of a bladder expansion;

[0057] Figure 4 It shows that according to Figure 2 Example of capsule in Figure 1 flowcharts of example methods for use in example processes; and

[0058] Figure 5 is used for Figure 1 Schematic enlargement of an example of an alternative base portion of a bladder during an example procedure. DETAILED DESCRIPTION

[0059] The following description presents exemplary embodiments and is related to the accompanying Figure 1 It is used to explain the principles of the embodiments of the present invention.

[0060] Figure 1 A process for making a bottle from pulp (i.e., which may form the basis of an example fiber suspension) is shown. The process is merely exemplary and is provided to give context to examples of the invention. Broadly speaking, the exemplary process includes: providing a fiber suspension; introducing the fiber suspension into a mold cavity of a porous first mold, and using the porous first mold to expel a liquid (such as water) from the fiber suspension to produce a wet precursor or embryo (which itself may be considered a molded container); further molding the wet precursor in a mold to produce a further molded container; coating the further molded container to produce a coated molded container; drying the coated molded container to produce a dry container; and applying a closure to the dry container. As will be apparent at least from the following description, the exemplary process may be modified to provide variations that may embody other examples of the invention.

[0061] In this example, providing a fiber suspension comprises: preparing a fiber suspension from the ingredients of the fiber suspension. More specifically, the preparation comprises: providing pulp fibers such as paper pulp fibers, and mixing the pulp fibers with a liquid to provide hydrated pulp fibers. In this example, the pulp fibers are provided by a supplier in sheet form and the liquid comprises water and one or more additives. In this example, the liquid is mixed with the pulp fibers to provide hydrated pulp fibers having a solid fiber content of 1 wt % to 5 wt % (based on the dry mass of the fibers). In an example, the one or more additives comprise a sizing agent such as alkyl ketene dimer (AKD). The hydrated pulp fibers typically comprise 0.4 wt % AKD relative to the total dry mass of solid fibers in the hydrated pulp fibers. In some examples, one or more additives are present in the liquid when the pulp fibers are mixed with the liquid. In some examples, one or more additives are included in the hydrated pulp fibers after the pulp fibers are mixed with the liquid (e.g., the pulp fibers are hydrated for a period of time, such as 2 to 16 hours, and then the one or more additives are supplied to the hydrated pulp fibers). The hydrated pulp fibers are passed between plates that move relative to each other in a valley beater 11 or refiner. This causes some or all of the fibers to fibrillate, which means causing the cell walls of these fibers to become partially stratified so that the wet surfaces of these fibers include protruding hairs or fibrillations. These fibrillations will help increase the bonding strength of the fibers in the dried final product. In other examples, the valley beater 11 or refiner may be omitted.

[0062] The resulting processed pulp is stored in a vat 12 in a relatively concentrated form (e.g., 1 wt % to 5 wt % solid fiber content) to reduce required storage space. At an appropriate time, the processed pulp is transferred to a mixing station 13 where it is diluted with additional water and optionally mixed with one or more additives (in addition or in lieu of being provided with the hydrated pulp fibers) to provide a fiber suspension ready for molding. In this example, solid fibers comprise 0.7 wt % of the resulting fiber suspension (based on the dry weight of the fibers), but in other examples, the proportion of solid fibers in the fiber suspension may vary, such as another value in the range of 0.5 wt % to 5 wt %, or 0.1 wt % to 1 wt % of the fiber suspension (based on the dry weight of the fibers). In some examples, the one or more additives mixed with the processed pulp and water include: a dewatering agent, such as modified and / or unmodified polyethyleneimine (PEI), for example, available under the trade name SK. In some examples, one or more additives are mixed with water, and then the water and one or more additives are mixed with the processed pulp; in other examples, the processed pulp is mixed with water, and then the one or more additives are mixed with the processed pulp and water. The fiber suspension typically contains 0.3% by weight of the total dry mass of solid fibers. SK. The mixing of the fiber suspension at the mixing station 13 helps to homogenize the fiber suspension. In other examples, the process pulp or fiber suspension may be provided in other ways, such as a ready-made supply.

[0063] In this example, the porous first mold 15 includes two half molds that can move toward and away from each other, in this case using a hydraulic ram. In this example, each of the half molds is an integral or single tool formed by additive manufacturing (e.g., 3D printing) that defines a mold contour, and when the half molds are brought into contact with each other, their respective mold contours cooperate to define a mold cavity in which a wet precursor or a molded container is to be formed. Each half mold itself can define a smaller mold cavity, and when cooperating with the second half mold, the smaller mold cavity can be combined to provide an overall mold cavity. The two half molds themselves can be regarded as "splits" or "molds", and the overall porous first mold 15 can be regarded as a "split mold" or equally a "mold". In other examples, the porous first mold 15 may include more than two split shells that cooperate to define a mold cavity, such as 3, 4 or 6 split shells.

[0064] exist Figure 1 In the process, the fiber suspension (also called slurry) is top-filled into the porous mold 15, which is the opposite of the molding process in which the mold is immersed in the slurry. The fiber suspension is sucked out through the pipeline 16 under vacuum and sucked out into the porous mold 15, wherein the excess suspension liquid is sucked out through the porous mold 15 under vacuum through the pipeline 18 into the storage tank 17. The shot mass can be controlled by measuring (e.g. weighing) the amount of liquid sucked into the storage tank 17. In Figure 1 1, a weighing scale platform supporting the reservoir 17 can be seen. Once the desired amount of liquid (e.g. a predetermined volume such as 10 liters, or a predetermined mass such as 10 kg) has been collected in the reservoir 17, the suction of the suspension liquid through the porous mold 15 is stopped and the porous mold 15 is opened to the ambient air. In this example, the suspension liquid sucked out in the line 16 together with the fiber suspension is water, or mainly water (because additives may also be present). The liquid sucked out under vacuum via the line 18 and into the reservoir 17 is substantially free of fibers, because these fibers are left on the walls of the porous mold 15 to form the embryo of the molded container.

[0065] In one form, in order to remove additional suspension liquid (e.g., water) from the embryo and form or strengthen the three-dimensional shape of the container, an impermeable expansion element 19, such as a collapsible bladder, is inserted into the porous mold 15 and expanded to act as an internal high-pressure core structure of the porous mold 15. This process strengthens the wet embryo so that it can be handled and displaces water from between the fibers, thereby improving the efficiency of the subsequent drying process. A hydraulic pump 20 is used to actuate and adjust the expansion element 19. The pump 20 has a cylinder that displaces the fluid in the pipeline 21 into the expansion element 19 so that the expansion element 19 expands radially and expands to be consistent with the mold cavity. The fluid in the pipeline 21 is preferably incompressible, such as water. Water also has the following advantages over other incompressible liquids: any leakage or bursting of the bladder 19 will not introduce new substances into the system (because the suspension liquid is already water, or mainly water).

[0066] Demolding occurs when the porous mold 15 is opened to remove the self-supporting molded container 22. Mold cleaning 23 is preferably performed subsequently to remove small fibers and maintain the porosity of the porous mold 15. In this example, a radially projected high-pressure jet is injected into the mold cavity when the mold 15 is opened. This will cause the fibers to break away from the walls of the mold cavity. Alternatively or additionally, water from a reservoir 17 is pressurized and passed through the back of the porous mold 15 to dislodge trapped fibers. The water is drained to circulate back to the upstream part of the system. It is worth noting that cleaning is important for conditioning the porous mold 15 for reuse. The porous mold 15 may look clean after removing the container, but not cleaning it may compromise its performance.

[0067] according to Figure 1 , the formed but unfinished container 22 is then transported to a second molding station where, in a mold 25 of, for example, aluminum, pressure and heat are applied to thermoform the desired neck and surface finish, optionally including embossed and / or concave surface features. After the two halves of the mold 25 are closed around the container 22, the intensifier is turned on. For example, a bladder 26 (e.g., a thermoforming bladder 26) is inserted into the container 22. The bladder 26 is inflated by a pump 28 via a line 27 to supply a pressurized fluid, such as air, water, or oil. Optionally, during supply, the pressurized fluid is heated, for example, with a heater, or alternatively, cooled, for example, with a heat exchanger. The outer mold block 24 of the mold 25 and / or the mold 25 itself may also or alternatively be heated. The state of the molded container 22 after thermoforming is significantly more rigid with a more compressed sidewall than when it was demolded from the porous mold 15.

[0068] As shown, a drying stage 29 (e.g., a microwave drying process or other drying process) is performed downstream of the thermoforming. In one example, the drying stage 29 is performed before the thermoforming. However, molding in the mold 25 requires a certain water content to facilitate bonding during the compression process. Figure 1 An additional drying stage 30 is shown following drying stage 29, which may utilize hot air circulated over molded container 22, such as in a "hot box." In some examples, microwave or other drying processes may be performed at multiple stages of the overall manufacturing process.

[0069] The molded container 22 is then subjected to a coating phase, during which, in this example, a spray gun 31 is inserted into the molded container 22 and one or more surface coatings are applied to the inner wall of the molded container 22. In another example, the molded container 22 is instead filled with a liquid that coats the inner wall of the molded container 22. In fact, such coatings provide a protective layer to prevent the contents from flowing out into the bottle wall, which may penetrate and / or weaken the bottle wall. The coating will be selected according to the expected contents of the container 22, for example, beverages, detergents, medicines, etc. In some examples, an additional drying phase 30 is performed after the coating phase (or before and after the coating phase). In this example, the molded container 22 is then subjected to a curing process 34 that can be configured or optimized according to the coating, for example, drying for 24 hours under ambient conditions or by a flash drying method. In some examples, for example, the additional drying phase 30 occurs after the coating phase, the curing process 34 can be omitted.

[0070] At an appropriate stage of production (e.g., during thermoforming, or before or after coating), a closure or finish forming process may be performed on the molded container 22. For example, Figure 1 As shown, a neck fitting 35 may be attached. In some examples, an exterior coating is applied to the molded container 22, as shown in an additional coating stage 32. In one example, the molded container 22 is immersed in a liquid that coats its exterior surface, as shown in FIG. Figure 1 As shown. One or more additional drying or curing processes may then be performed. For example, the molded container 22 may be allowed to dry in warm air. The molded container 22 may thus be fully formed and ready to receive contents therein.

[0071] exist Figure 1 In the exemplary process of FIG. 1 , a bladder 19 is used to force a fiber suspension in wet embryo form into contact with a porous mold 15, and a thermoforming bladder 26 is used to force an unfinished container 22, which can be considered a partially formed container, into contact with an aluminum mold 25. In this way, compressive forces can be applied to the fiber suspension or the partially formed container to further form the desired shape of the final container.

[0072] Available for Figure 1 The example bladder 100 in any of these steps of the example process Figure 2 Here, bladder 100 is shown supported and exposed to the surrounding external atmosphere, e.g., with substantially no radially inward or outward pressure applied to bladder 100.

[0073] The bladder 100 is a one-piece structure formed of silicone having a Shore A hardness of about 40 and is substantially hollow. The bladder 100 has a neck portion 102, a body portion 104 and a base portion 106. The neck portion 100 is generally cylindrical in form and defines an opening 107 into the interior of the bladder. The neck portion 102 has a maximum width A of about 30 mm measured between two diametrically opposed points on the outer surface of the neck portion 102 and has a substantially constant wall thickness B of about 5.2 mm.

[0074] The body portion 104 begins at the end of the neck portion 102 opposite the opening 107 and includes a shoulder portion 108 proximal to the neck portion 102 and a lower portion 110 distal to the neck portion 102. The shoulder portion 108 flares outward from the neck portion 102 and has a substantially constant wall thickness C of about 2.7 mm. The interface between the shoulder portion 108 and the lower portion 110 occurs at the point of maximum width D of the body portion 104. The maximum width D of the body portion 104 measured between two opposite points diametrically opposite on the outer surface of the body portion 104 is about 43 mm.

[0075] The lower portion 110 tapers inwardly from the maximum width D of the body portion 104 toward the base portion 106. The minimum width E of the lower portion 110 measured between two diametrically opposed points on the outer surface of the lower portion 108 is about 40 mm. The wall thickness of the lower portion 110 gradually increases along the length of the lower portion 110 from the wall thickness C of 2.7 mm at the shoulder portion 108 to the maximum wall thickness F of about 4.4 mm at the body portion 104 in a manner without a step change in thickness. The maximum thickness F of the body portion 104 occurs at the farthest side end of the body portion 104 from the neck portion 102. Therefore, the wall thickness of the body portion 104 increases along its length from the minimum wall thickness C of about 2.7 mm at the shoulder portion 108 to the maximum wall thickness F of about 4.4 mm at the lower portion 110.

[0076] The transition region 112 between the lower portion 110 and the base portion 106 has a reduced wall thickness G relative to the maximum wall thickness F of the lower portion 110 of approximately 3 mm.

[0077] The base portion 106 has the form of a spherical dome located at the end of the body portion 104 opposite the neck portion 102, such that the body portion 104 is intermediate the neck portion 102 and the base portion 106. The base portion 106 has a maximum width H of about 44 mm measured between two opposite points on the outer surface of the base portion 106. In this particular stage of expansion, this can be regarded as the maximum width of the bladder 100 as a whole. The base portion 106 has a substantially constant wall thickness I of about 4 mm.

[0078] In use, the bladder 100 is used, for example, as a thermoformed bladder 26 and is inserted into an unfinished container 22 , ie, a partially formed container, held within an aluminum mold 25 .

[0079] The bladder 26 is inflated by a pump 28 supplying a pressurized fluid, such as air, water or oil, to the interior of the bladder 26 via a line 27 so that the bladder 26 expands to apply a compressive force to the unfinished container 22 as part of the thermoforming process.

[0080] Because the main body portion 104 has a wall thickness that varies along the length of the wall, the expansion of the main body portion 104 of the bladder 100 is controlled so that when inflated, the thinner areas of the wall expand preferentially over the thicker areas of the wall. Therefore, by varying the thickness of the wall of the main body portion 104, the contact of the main body portion 104 with the unfinished container when the bladder 100 is expanded will be controlled. Figure 2 In the example of FIG. 1 , the relatively thin shoulder portion 108 of the wall expands before the relatively thick lower portion 110 of the wall expands, so that the shoulder portion 108 of the wall contacts the unfinished container 22 before the lower portion 110 of the wall contacts the unfinished container 22. Such expansion Figure 3 This is schematically illustrated via arrows, where the relative size of the arrows is used to indicate the likelihood of expansion, with larger arrows indicating those areas that are likely to expand first.

[0081] By controlling this initial contact point of the main body portion 104 with the unfinished container 22, the subsequent expansion of the bladder 100 within the unfinished container 22 can be controlled. Figure 2 With the example bladder 100 of FIG. 1 , it has been found that, upon inflation, the shoulder portion 108 may initially expand to contact a corresponding shoulder portion of the unfinished container 22, to contact the remainder of the body portion 104, and in fact to contact the base portion 106, and then subsequently expand to fill the unfinished container 22. This may ensure that the bladder is able to contact the unfinished container 22 with sufficient pressure to ensure adequate compaction of the material of the unfinished container 22.

[0082] The bladder 100 may thus provide a container having greater and potentially more uniform strength when compared to a container formed, for example, by using an expandable member having a body portion of constant thickness.

[0083] By having the neck portion 102 have a relatively thicker further wall portion than the wall of the body portion 104, increased strength may be provided in the region of the opening 107 of the bladder 100, where, in use, the bladder may be connected to the line 27. The relatively thicker further wall portion of the neck portion 102 than the wall of the body portion 104 may also promote expansion of the body portion 104 in preference to the neck portion 102. This may be beneficial in the case where the body portion 104 has a greater width than the neck portion 102, as is the case with most containers in the form of bottles, since less expansion of the neck portion 102 is required to achieve the desired compaction.

[0084] Additionally, the maximum width H of the base portion 106 is greater than the maximum width D of the body portion 104, and is actually greater than the maximum width A of the neck portion 102. This means that when the bladder 100 expands, the base portion 106 may be more likely to be urged toward the periphery of the base of the unfinished container 22 when compared to, for example, a bladder having a body portion and base portion of the same width. This ensures that the bladder 100 can contact an area of ​​the periphery of the base of the unfinished container 22 with sufficient pressure to ensure adequate compaction of the unfinished container.

[0085] Figure 4 The flowchart shows the Figure 2 Example of a bladder 100 in Figure 1 An example method 300 for use in an example process of forming a container from a fiber suspension is provided. The method 300 includes providing 302 a component in a mold cavity of a mold, wherein the component is a fiber suspension or a partially formed container. The method 300 includes providing 304 a bladder 100 in the mold cavity. The method 300 includes expanding 306 the bladder 100 such that relatively thin regions of the wall of the body portion 104 expand before relatively thick regions of the wall of the body portion 104 so as to drive the component against an inner surface of the mold cavity during a process of forming a container from the component.

[0086] Although described above with respect to an unfinished container 22, it should be understood that Figure 2 The example bladder 100 may also be used to apply pressure to a wet embryo in the manner previously described.

[0087] It should also be appreciated that a bladder is contemplated wherein the wall thickness of the body portion 104 varies along its length, whereas a feature in which the maximum width H of the base portion is greater than the maximum width D of the body portion 104, or vice versa, is not contemplated.

[0088] In addition, although Figure 2 The bladder 100 in the example of FIG. 1 has been described as having certain dimensions, but it should be understood that the teachings herein are equally applicable to bladders having other dimensions.

[0089] For example, bladders having a wall thickness F of the lower portion 110 of about 1.2 to 2.0 times, about 1.4 to 1.8 times, and about 1.6 times the wall thickness C of the shoulder portion 108 are contemplated. Bladders having a wall thickness C of the shoulder portion 108 of about 1.2 mm to 4.0 mm, about 1.5 mm to 3.0 mm, and about 2.7 mm are contemplated. Bladders having a wall thickness F of the lower portion 110 of about 1.7 mm to 7.2 mm, about 2.1 mm to 5.4 mm, and about 4.4 mm are contemplated.

[0090] Bladders having a wall thickness B of neck portion 102 of about 1.1 to 1.5 times and about 1.2 times the wall thickness F of lower portion 110 are contemplated. Bladders having a wall thickness B of neck portion 102 of about 3.1 to 10.8 mm, about 3.9 to 8.1 mm and about 5.2 mm are contemplated.

[0091] Bladders are contemplated in which the maximum width H of the base portion is no more than 10%, no more than 5%, or no more than 1% greater than the maximum width D of the main body portion 104. Bladders are contemplated in which the maximum width H of the base portion is about 25 mm to 70 mm, such as about 40 mm to 55 mm. Bladders are contemplated in which the maximum width D of the main body portion 104 is about 24 mm to 69 mm, such as about 39 mm to 54 mm.

[0092] Bladders are contemplated in which the maximum width D of the body portion 104 is no more than 80%, no more than 70%, no more than 60%, or no more than 50% greater than the maximum width A of the neck portion 102. Bladders are contemplated in which the maximum width A of the neck portion 102 is about 23 mm to 68 mm, such as about 38 mm to 53 mm.

[0093] Other variations are also contemplated where the wall thickness of various portions of the bladder 100 differ. One such example is shown in Figure 5 , wherein the base portion has a maximum thickness J in an area corresponding to the base of the unfinished container 22 (e.g., an area on the farthest side of the opening 107), and the base portion 106 has a minimum wall thickness K in an area corresponding to the periphery of the base of the unfinished container 22. Providing such an area of ​​the base portion 106 having the minimum wall thickness, which is actually equivalent to the corner of the base portion 106, can push the bladder 100 to expand to fill the area corresponding to the corner of the unfinished container 22 or the junction between the side wall and the base, so that sufficient pressing force can be applied to such area of ​​the unfinished container 22.

[0094] Example embodiments of the invention have been discussed with reference to the examples illustrated. However, it will be appreciated that changes and modifications may be made without departing from the scope of the invention as defined by the appended claims.

Claims

1. An expandable member for use in molding a container in a cavity of a mold, the expandable member comprising: a neck portion defining an opening of the expandable member, the neck portion having a first width; as well as a main body portion having a second width different from the first width; Wherein the body portion comprises a wall having a thickness that varies along the length of the wall.

2. An expandable member as described in claim 1, wherein the thickness of the wall gradually changes along the length of the wall.

3. An expandable member as described in claim 1 or claim 2, wherein the main body portion includes a shoulder portion proximal to the neck portion and a lower portion distal to the neck portion, the shoulder portion having a first wall thickness and the lower portion having a second wall thickness greater than the first wall thickness.

4. An expandable member as described in claim 3, wherein the second wall thickness is between 1.2 times and 2.0 times the first wall thickness.

5. An expandable member as claimed in any one of claims 1 to 4, wherein the neck portion includes another wall portion having another wall thickness that is greater than a maximum wall thickness of the wall of the body portion.

6. An expandable member as described in any one of claims 1 to 5, wherein the expandable member includes a base portion, the base portion is located at an end of the main body portion opposite to the neck portion, the base portion includes a third width, and the third width is greater than the second width.

7. An expandable member as described in claim 6, wherein a transition region between the main body portion and the base portion includes an area of ​​reduced wall thickness relative to adjacent areas of the main body portion.

8. An expandable member as described in claim 6 or claim 7, wherein the base portion is circular.

9. An expandable member as described in any one of claims 6 to 8, wherein the wall thickness of the base portion varies, and the minimum wall thickness of the base portion is located between the most distal portion of the base portion from the opening and the transition area between the main body portion and the base portion.

10. A container molding system comprising: a container mold comprising a mold cavity for receiving a component, wherein the component is a fiber suspension or a partially formed container; as well as An expandable member as claimed in any one of claims 1 to 9, said expandable member being expandable in said mould cavity so as to urge said component against an inner surface of said mould cavity during the process of forming said container from said component.

11. A container molding system as described in claim 10, wherein the container molding system includes an expansion fluid source that can be fluidly connected to the expandable member, so that when the expandable member is inserted into the mold cavity, the expansion fluid can be selectively supplied to the interior of the expandable member.

12. A container moulding system as claimed in claim 10 or claim 11, wherein the container moulding system comprises a heat source for supplying heat to the component while the component is retained within the mould cavity.

13. The container molding system of any one of claims 10 to 12, wherein the container molding system is at least one of a fiber container molding system and a pulp container molding system.

14. A method of molding a container, the method comprising: providing a component in a mold cavity of a mold, wherein the component is a fiber suspension or a partially formed container; providing an expandable member as claimed in any one of claims 1 to 9 in the mold cavity; as well as The expandable member is expanded so that relatively thin regions of the wall of the body portion expand before relatively thick regions of the wall of the body portion and so as to drive the component against the inner surface of the mold cavity during the process of forming the container from the component.

15. The method of claim 14, comprising applying heat to the component in the mold cavity.

16. The method of claim 14 or claim 15, wherein the method is a method of moulding at least one of a fibre container and a pulp container.

17. A container obtainable or obtained by a method of manufacture comprising the method as claimed in any one of claims 14 to 16.

18. A container obtainable or obtained by the method of making as claimed in claim 17, wherein the container is at least one of a fiber container and a pulp container.

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