System and method for molding molded products

Abstract

A system and method for producing a molded article, such as a one-piece container, includes delivering a fiber suspension to a porous mold and removing the suspending liquid (e.g., water) through the pores of the porous mold. An inflatable bladder is inserted into the mold in a collapsed state and then inflated to apply pressure to the interior walls of the molded article to remove water. The wet nascent container is then transferred to a non-porous mold where the inflatable bladder applies internal pressure to compress the walls and further remove water. The container may be further dried by microwave and / or air drying and coated with a protective layer.

Description

Technical Field

[0001] The present invention relates to a forming system and method for formed articles. In particular, the present invention relates to forming containers from fiber suspensions, such as paper pulp. The article / container can be consumer packaging useful for holding liquids.

Background Art

[0002] It is desirable to reduce the use of plastics, especially in packaging. Trays and simple shapes are generally made from paper pulp, but it is more difficult to create what is needed to hold more complex objects and liquids.

[0003] Each of Patent Documents 1, 2, 3, and 4 describes forming a formed article from paper pulp using a mold. Since the mold has openings or is porous, the pulp introduced into the mold can be removed by applying suction to the mixed suspension. The pulp remaining after the liquid is removed conforms to the shape of the mold. In a second step, an expandable member in a folded state is introduced into the mold and expanded to apply pressure to the inner wall of the article being formed, distributing the pulp to a more uniform wall thickness and further discharging the suspension from the article and the mold. The formed article is removed from the mold and dried to remove the remaining liquid.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

[0005] The present invention relates to advancing the above techniques in order to improve the specifications of the resulting molded articles or at least to provide alternatives to the public. The present invention is particularly suited to manufacturing resealable bottles for holding liquids such as detergents and beverages.

[0006] In a broad view of carrying out the present invention, the method is defined according to claim 1. Apparatuses and systems according to the present invention are defined in claim 24. Other useful method steps and features are outlined in dependent claims.

[0007] The present invention is intended to ultimately produce an improved pulp bottle structure made of a single, integrated structure. Therefore, the novel bottles obtained by this process are within the scope of the present invention. The articles produced by this process are three-dimensional hollow forms such as cups, bottles, or jars, in contrast to mainly shallow shapes such as plates.

[0008] In certain forms, the method of the present invention involves preparing a fiber suspension of fibers suspended in a suspending liquid. The preparation may involve a pulp-quality refiner such as a valley beater and a tank for hydration using a shear or paddle mixer. This step may be carried out continuously or in batches as part of the process. The concentrated form of the suspension may be prepared for dilution immediately before molding. The most effective concentration for dispensing into a mold is approximately 0.5–1% fiber.

[0009] While a predetermined volume of process water is continuously supplied to a closed, two-part porous mold (e.g., composed of a negative 3D image of a desired molded product such as a bottle), the suspension is removed through the pores of the porous mold, for example, by vacuum pressure / pump. The predetermined volume can be monitored by metering the suspension removed from the mold. As an example, 10 liters of process water may be collected in a tank outside the porous mold, leaving pulp fibers on the surface of the mold.

[0010] In one configuration of the system, after substantially all of the suspension has been removed, an impermeable surface (e.g., a folded inflatable bladder) is inserted into the wet molded article to apply pressure to the inner wall of the article (e.g., by air pressure or hydraulic expansion, using air, water, or oil) and further expel the suspension through the pores of the porous mold. The molded article can then be removed for further drying steps.

[0011] According to the present invention, the molded article is also subjected to a non-porous mold and transferred, for example, to a second or further non-porous mold. Therefore, in order to impart the shape of the non-porous mold to the outer wall of the molded article, further pressure may be applied to the inner wall of the molded article via an impermeable surface (for example, any of the same inflatable bladder, second bladder, or other form of compression means, whether strictly "impermeable" or not). Such a step is preferably heated for "thermoforming" to expel any remaining suspension and to strengthen the wall of the molded article by compression and drying.

[0012] The walls of the porous mold are preferably cleaned after the article has been removed, for example, by returning the discharged suspension through the mold and / or by using a water jet against the mold walls. Cleaning removes residual fibers from the porous surface and readjusts the mold for repeated use.

[0013] The drying step of the method / system may utilize microwave energy, for example, in a continuous or batch delivery system. The articles may be dried either before or after the non-porous stage, or both.

[0014] The coating stage may apply a protective layer to the surface of the molded article. For example, the coating step may include spraying the base and sides of the molded article from the inside and / or outside. The coating may be a non-heat-sealable aqueous barrier that can be recycled with the bottle after use.

[0015] Closure elements can be applied to openings in molded articles (for example, after coating / drying). Closure elements may include neck fitment materials having annular features for sealing the opening. One form of the neck fitment material includes foil seals, corks, and / or caps.

[0016] The present invention is embodied by a system for molding an article, the system comprising a source of a fiber suspension of fibers suspended in a suspension liquid, a dispensing means for dispensing the fiber suspension into a first porous mold, and a suction pump for removing the suspension through the pores of the porous mold to mold the article, the system optionally comprising an inflatable pressurizing member inserted into the mold in a folded state and then inflated to apply pressure to the inner wall of the article. Means are provided for serving the article into a non-porous mold. The non-porous mold is likely to be a second or further mold, but in principle may be the first mold converted into a second non-porous state. For example, pressure is applied to the inner wall of the article in the non-porous mold via an inflatable pressurizing member or a second inflatable pressurizing member. Conveying means are provided for removing the article from the mold.

[0017] The container according to the present invention is molded from a fiber suspension and comprises a substantially integral / single structure and a neck attachment member material or molded threads at the neck opening.

[0018] In one embodiment, a neck attachment member is provided for a container made from a fiber suspension, the neck attachment member comprising a tubular body and a substantially continuous flange around the surface of the tubular body for coupling and / or abutting with the opening of a container made from a fiber suspension. The tubular body may be cylindrical, and the flange may be annular. Threads or female threads may be formed on the surface of the body. A cap or plug may be provided to serve as a closure for the opening of the tubular body. [Brief explanation of the drawing]

[0019] [Figure 1]Figure 1 shows a system / process for implementing the method according to the present invention. [Figure 2] Figure 2 shows a 3D porous mold according to the present invention. [Figure 3] Figure 3 shows a molded product removed from the 3D porous mold. [Figure 4] Figure 4 shows a cross-sectional view of the opening of the bottle and the attachment member. [Figure 5] Figure 5 shows a view of the attachment member of Figure 4. [Figure 6] Figure 6 shows another view of the bottle opening attachment member. [Figure 7] Figure 7 shows a cross-sectional view of the bottle opening structure of Figure 6.

Mode for Carrying Out the Invention

[0020] The following description presents exemplary embodiments and, together with the drawings, serves to explain the principles of the present invention. However, changes will be apparent to those skilled in the art, and such changes are considered to be covered by this description, so the scope of the present invention is not intended to be limited to the exact details of the embodiments or the exact compliance with all steps. The terms used for the components used in this application should be given a broad interpretation that includes equivalent functions and features. In some cases, several alternative terms (synonyms) for structural features are provided, but such terms are not intended to be exhaustive.

[0021] The descriptive terms should also be given the broadest possible interpretation. For example, when interpreting each description in this specification using the term "comprising", it means "at least partially constituted" so that features other than the features preceding such term may also exist. Related terms such as "comprises", "comprised of" are interpreted in the same way. Terms indicating directions such as "vertical", "horizontal", "up", "down", "upper side" and "lower side" are used for the convenience of explanation when the drawings are usually referred to, and are not intended to be finally limited when equivalent functions can be obtained by alternative dimensions and / or directions.

[0022] The description in this application refers to embodiments having specific combinations of steps or features, but it is assumed that further combinations and cross-combinations of steps or features that are interchangeable between embodiments are possible. In fact, isolated features may function as an invention independently of other features, and implementation as a complete combination is not necessarily required.

[0023] Figure 1 outlines an example of a process incorporating the present invention, that is, a process comprising the steps of preparing a pulp suspension, introducing it into a porous mold, discharging the suspension from the mold to produce an unfinished article, and exposing the unfinished article to a non-porous mold. The article may then be dried, or at an intermediate stage, with or without an internal protective coating. Further details of the embodiments are described below.

[0024] In the first stage of pulp processing and storage, unprocessed pulp fibers are supplied directly from the supplier in sheet form, rehydrated, and passed between plates of a valley beater 11 in relative motion. One of the things that happens during fiber processing is fibrillation, i.e., partial peeling of the cell walls, which results in a fuzzy appearance on the wet fiber surface. The resulting "hairs," also called small fibers, increase the relative strength of the bonds between fibers in the dried product.

[0025] During this process, desired additives are used to alter the bottle's structure, strength, and molding properties, potentially reducing costs. Sizing, fillers, and buffers can be evaluated as needed.

[0026] The concentrated processed pulp can be stored in the vat 12 until needed, reducing the total amount of storage space required.

[0027] Dilution, for example, 0.5-5% solid fiber in an aqueous suspension, is performed at the mixing station 13 immediately before molding. Mixing in this step ensures homogenization of the slurry without altering the properties of the pulp. As shown in the figure, bubbles rise to the top, displacing the slurry above them and drawing the liquid at the bottom level upwards.

[0028] The initial molding step 14 involves taking up a porous mold, for example, a 3D-printed tool 15, which is clamped in two halves together using a hydraulic ram. In the illustrated embodiment of the invention, the slurry is filled from above the tool 15, in contrast to a molding process in which the mold is immersed in the slurry. The pulp slurry is then drawn through the porous tool 15 under vacuum via a tube 16, similar to an injection molding machine. The shot mass can be controlled by measuring (e.g., weighing) the mass / volume of water drawn into the tank 17. Once the desired mass is reached, the tool is released into the ambient air. A weighing platform supporting the tank 17 is shown in Figure 1.

[0029] The suspension drawn in with the fiber suspension through tube 16 is water. The water drawn into tank 17 through tube 18 under vacuum is substantially free of fibers because the fibers remain attached to the walls of the porous tool 15. As an example, the suction of the suspension 18 through mold 15 is continued until a predetermined amount (e.g., 10 liters) of water is collected in tank 17.

[0030] At this stage, the “article” within tool 15 is formed, but it is a wet shape held against the inner wall of the mold.

[0031] In one embodiment, to further remove the suspension (water) and enhance the shape of the 3D object, an impermeable expansion element, such as a collapsible bladder, is inserted into the mold 15 to act as an internal high-pressure core structure for the tool. As described above, this process enhances the wet "initial stage" bottle so that it can be handled (or transported by mechanized means) before drying and improves the efficiency of the drying process by moving water between the cellulose fibers. The bladder 19 is actuated / regulated using a hydraulic pump 20 equipped with a cylinder that moves the fluid in the tube 21 into the bladder in order to expand the bladder 19 radially to match the cavity of the tool. The fluid in the tube 21 is preferably incompressible, such as water. Water also has the advantage that if any leakage or rupture of the bladder occurs, no new material is introduced into the system (since the suspension is already water).

[0032] In one embodiment, positive hydraulic pressure from tank 17 can be used to counteract the forces from the internal bladder after molding has been performed.

[0033] Figures 2 and 3 illustrate the appearance of a block 14 consisting of two parts that house a porous mold 15 (a non-porous mold 25 may have a similar appearance, as will be described later). Channels passing through block 14 communicate with the porous mold 15 and provide pathways for the suspension drawn through the mold and for backflow during the washing step (described below).

[0034] Demolding occurs in the step where the mold tool 15 is opened to remove the independent article 22 (as shown in Figure 4). Subsequently, a cleaning step 23 is preferably performed to remove small fibers and maintain the pores of the tool. In the illustrated form, while the tool is open, a high-pressure jet sprayed radially is inserted into the molding chamber. This removes surface fibers. Alternatively, water from a tank 17 is pressurized through the back of the tool 15 to remove trapped fibers. The water is discharged and recycled for the upstream steps of the system. It is worth noting that cleaning is a crucial step in preparing the tool for reuse. After the article is removed, the tool may look clean, but its performance will be reduced without the cleaning step.

[0035] According to Figure 1, the formed but unfinished article 22 is then transported to a second or further forming step 24, in which pressure and / or heat is applied within a non-porous tool 25, for example, aluminum, to thermoform the desired neck and surface finish. After the bisection of the tool 25 (optionally including negative surface features for debossing / embossing, etc.) closes around the article 22, a pressurizing means, for example, a second bladder 26 (or the same bladder 19 as in the previous process) inserted into the article 22 is used. The bladder 26 is inflated by a heated pump 28 that supplies a pressurized fluid, for example, water or oil, through a tube 27. The block of the external mold 24 and the tool 25 may also be heated or alternatively.

[0036] The state of the molded product 22 after thermoforming is significantly more rigid and the side walls are more compressed compared to the state at the time of demolding from the porous mold 15.

[0037] In the illustrated configuration, a microwave stage 29 is used as a fast and efficient drying method that does not damage the bottles. For example, a 25kW microwave for processing 100g of bottles with 200g of water allows for drying 1M per year, using 740kJ, with 1.8kW of microwave power applied to each bottle for 7 minutes. This system can be scaled down or up in proportion to the microwave power and the mass of water. Alternative drying systems can be incorporated into the method of the present invention.

[0038] The improved extraction system further enhances the drying speed and can be optimized for different bottle shapes.

[0039] The drying stage 29 (microwave or other) can be applied downstream of or upstream of the non-porous molding as a pre-molding step, as shown in the figure. However, molding in the non-porous mold 25 requires some moisture to aid in bonding during the compression process. In some configurations, microwave or other drying options may be applied at multiple stages of the process.

[0040] Figure 1 shows a further drying stage 30 that utilizes hot air circulating in a "hot box," for example, on the bottle, prior to the coating stage in which a spray lance 31 inserted into the bottle 22 applies a surface coating to the inner wall of the bottle. In practice, the coating provides a protective layer that prevents liquid contents from flowing out onto the bottle wall and potentially penetrating and / or weakening the bottle wall. The coating is selected according to the intended contents of the bottle 22, such as beverages or detergents.

[0041] The curing method in step 34 can be optimized depending on the coating, for example, by drying under ambient conditions for 24 hours or by flash drying.

[0042] A closing or opening-forming process may be performed on the article at an appropriate stage of production (e.g., during thermoforming, before or after coating).

[0043] Figures 4 and 5 show a first embodiment of the neck attachment member 35, in which a seal is provided by adhering a tubular body to a paper bottle 22. The annular channel 36 of the tubular body provides a support surface for receiving and concealing the end of the bottle's mouth.

[0044] Figure 5 shows a cap 37 provided for connection to the mounting member material 35 by annular screw threads. However, the closure design can be adjusted to meet the specific needs of the end user's requirements.

[0045] Alternative embodiments of the closure / opening mechanism are shown in Figures 6 and 7, specifically illustrated by a ring structure 38 that may be formed from pulp fibers in a different compression molding process. This ring serves as a finishing step for the mouth of the bottle 22 and preferably provides a flat surface 39 to which a heat-sealed film can be applied.

[0046] In the illustrated configuration, the ring 38 includes an annular channel 40 for receiving the unfinished open end of the bottle 22. The channel 40 consists of an upright outer wall 41 and an upright inner wall 42, bridged by a flat / sealing surface 39. A draw angle may be incorporated into the wall to facilitate manufacturing (e.g., by pulp compression molding), but this is not essential for operation.

[0047] To accommodate the overall production of the molded product without generally using plastic, pulp fiber is the preferred material for manufacturing the ring 38, although other materials can also be used to manufacture the ring.

[0048] The ring 38 is preferably bonded to the article 22 or otherwise fixed in place to form a liquid-tight and airtight joint. Similarly, any circular foil or other sealing structure applied to the surface 39 should be airtightly bonded. To obtain a gas-impermeable structure, at least a surface coating may be required on the surface 39, in whole or in part, of the ring 38, for example, so as not to have any imperfections that would affect the seal by another sealing material (not shown).

[0049] For recyclability, it is possible to leave a portion of the ring uncoated, for example, to allow the pulp to access fluids during the recycling process, enabling the fibers to break down.

[0050] The ring 38 represents a pulp-based finishing solution for opening the article 22. Alternative structures are possible.

[0051] Gas-impermeable seals / membranes applied to the openings of articles are advantageous not only for single-use amounts of liquid (such as single-serving beverages) but also for larger capacities that can be transferred to another container (e.g., a pumpable container for refillable detergent or a glass spirit decanter) or directly attached to a dispenser (e.g., a pump associated with an upright bottle or optical device).

[0052] In summary, in one embodiment, the present invention can be described as a system and method for producing a molded article, such as a one-piece container, comprising delivering a fiber suspension to a porous mold and removing the suspension (e.g., water) through the pores of the porous mold. A collapsible bladder is inserted into the mold in a folded state and then inflated to apply pressure to the inner wall of the molded article and remove moisture. The container in its wet initial form is then transferred to a non-porous mold, where the collapsible bladder applies internal pressure to compress the walls and remove further moisture. The container may be further dried by microwave and / or air drying and coated with a protective layer.

Claims

1. A method for forming a molded product, To prepare a fiber suspension of fibers suspended in a suspension solution, The method involves dispensing the fiber suspension into a porous mold, the porous mold comprising cavity walls defining the outer shape of the molded product, the cavity walls comprising pores substantially throughout the area in contact with the molded product, and configured to discharge the suspension through the cavity walls. In order to deposit the suspended fibers onto the cavity wall to form the molded product, the suspension is removed through the pores, Transferring the molded product to a non-porous mold, To press the outer wall of the molded product against the non-porous mold, pressure is applied to the inner wall of the molded product, Removing the molded product from the non-porous mold, A method that includes this.

2. The method according to claim 1, wherein removing the suspension through the pores of the cavity wall includes applying pressure to the inner wall of the molded product through an impermeable surface.

3. The method according to claim 1 or 2, wherein applying pressure to the inner wall of the molded product with the non-porous mold is achieved via an impermeable surface in order to impart the shape of the non-porous mold to the outer wall of the molded product.

4. The method according to claim 2 or 3, wherein the molded product is heated in the non-porous mold.

5. The method according to any one of claims 2 to 4, wherein the impermeable surface used in the porous type and the non-porous type is the same.

6. The method according to any one of claims 1 to 5, comprising cleaning the walls of the porous mold after removing the molded product.

7. The method according to claim 6, wherein cleaning includes returning the discharged suspension through the pores of the porous cavity wall and / or using a water jet against the porous wall.

8. The method according to any one of claims 1 to 7, wherein the expandable pressurizing member includes an impermeable surface configured to be inserted into a mold in a folded state and then inflated to apply pressure to the inner wall of the molded product.

9. The method according to claim 8, wherein the inflatable pressurizing member is inflated with water or oil.

10. The method according to any one of claims 1 to 9, wherein the preparation of the fiber suspension includes the use of a valley beater.

11. The method according to any one of claims 1 to 10, wherein the fiber suspension supplied to the porous mold contains 0.5 to 3% solids.

12. The method according to any one of claims 1 to 11, wherein the fiber suspension is stored in a concentrated form before being diluted for supply to the porous mold.

13. The method according to any one of claims 1 to 12, comprising the step of drying the molded article.

14. The method according to any one of claims 2 to 5, wherein the step of drying the molded product utilizes microwave energy either before or after the non-porous mold, or both.

15. The method according to any one of claims 1 to 14, wherein the step of drying the molded product is performed using hot air.

16. The method according to any one of claims 1 to 15, comprising the step of coating the surface of the molded article.

17. The method according to claim 16, wherein the coating step includes spraying the internal base and sides of the molded product.

18. The method according to any one of claims 1 to 17, wherein the step of drying the molded product utilizes cold air.

19. The method according to any one of claims 1 to 18, comprising applying a closing element to the opening of the molded product.

20. The method according to claim 19, wherein the closing element includes a ring or neck mounting member having an annular feature that seals the opening.

21. The method according to claim 20, wherein the ring or neck attachment member is made of pulp fibers.

22. The method according to any one of claims 1 to 21, wherein at least one of the porous mold and the non-porous mold is a two-part mold for forming a substantially closed three-dimensional single shape.

23. The method according to any one of claims 1 to 22, wherein the molded product has a bottle shape in which the main body portion is wider than the neck portion.

24. A system for molding molded products, Source of fiber suspension of fibers suspended in suspension solution, A porous mold, the porous mold includes a cavity wall that defines the outer shape of the molded article, the cavity wall contains pores substantially over the entire area in contact with the molded article, and is configured to discharge the suspension through the cavity wall, A non-porous mold, which includes a cavity wall that defines the outer shape of the molded product, A delivery line configured to deliver the fiber suspension into the porous form, A suction pump configured to remove the suspended liquid through the pores of the porous cavity wall in order to deposit the suspended fibers onto the cavity wall and form the molded product, A transfer mechanism for transferring the molded product from the porous mold to the non-porous mold, A pressurizing mechanism configured to apply pressure to the inner wall of the molded product relative to the non-porous mold, A system that includes this.

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