Reusable plastic container

Abstract

The invention relates to a reusable plastic container (100) comprising a container body (20), a container bottom (10) and a container opening (30) located opposite the container bottom. On the container body (20) a repeating structure (21), in particular a honeycomb structure, is provided formed by recesses (22) and ribs (23) surrounding the recesses (22). Alternatively, grooves are provided on the container body. At least 90% of the surface of the recesses (22) and ribs (23) and / or grooves are visible from the container opening (30).

Description

Technical Field

[0001] This invention relates to a reusable plastic container according to the preamble of the independent claims. Background Technology

[0002] Reusable containers are, for example, containers that are returned to the point of sale and then reused, i.e., refilled containers.

[0003] This process is particularly well-known in glass bottles. However, these have been superseded by plastic bottles because their production, unlike glass or metal bottles, can be carried out with significantly lower forming energy. This has greatly improved the carbon dioxide balance.

[0004] Most plastic bottles are almost entirely recyclable. The materials extracted from old bottles can be reused.

[0005] In order to improve the environmental and energy balance, recommendations have been made to design plastic containers as reusable containers for multiple uses.

[0006] For plastic containers to be used as reusable containers, they must meet additional requirements associated with single-use containers. For example, they must be designed to not permanently deform during cleaning or use. This results in these containers being constructed with relatively thick walls. This leads to heavier bottles, such as 500ml bottles weighing between 35 g and 65 g and 1000ml bottles weighing between 50 g and 90 g.

[0007] To ensure the reusability of plastic containers, collected waste plastic containers must be washed before refilling. Because many plastic containers, such as those made of PET, soften and deform at relatively low temperatures (e.g., 80°C), they cannot be cleaned with boiling water. Therefore, the plastic containers are cleaned multiple times at lower temperatures using an alkaline solution, such as sodium hydroxide (NaOH) or potassium hydroxide (KOH). The use of 1.2% to 2.4% NaOH has proven feasible. The washing process is carried out at a temperature of 50°C to 70°C for 60 minutes.

[0008] However, polyesters, particularly PET and PEF, exhibit problematic performance in relation to alkali solutions. Therefore, stress cracks in plastic containers can become attack points for alkali solutions, at which degradation of the plastic can occur over time. In particular, the reaction between esters and alkali solutions can lead to saponification.

[0009] During hot washing, such containers also become smaller, and the thick walls help keep the shrinkage rate below 3% over 15 washing cycles.

[0010] However, as mentioned earlier, thick walls result in significant weight. This not only negatively impacts the ecological balance but also negatively affects manufacturing costs. For example, due to the increased weight, more energy must be consumed to transport empty and full bottles. Summary of the Invention

[0011] The object of this invention is to correct at least one drawback of the prior art. Specifically, a reusable plastic container should be created that requires fewer resources, preferably has low manufacturing costs, and in particular, high stability.

[0012] This objective is achieved by the reusable plastic container defined in this application. Further embodiments are described below.

[0013] The present invention discloses a reusable plastic container, comprising a container body, a container bottom, and a container opening positioned opposite the container bottom. The container body has a repeating structure formed by recesses and ribs surrounding the recesses. This structure is specifically formed as a honeycomb structure. At least 90% of the surface area of ​​the recesses and ribs is visible from the container opening.

[0014] This ensures that the corresponding surfaces can come into direct contact with the washing liquid from the container opening.

[0015] By definition, a dent is a deformation of the container body into the interior of the plastic container.

[0016] Studies have shown that laminar boundary layer formation is relatively rapid during washing, particularly in PET washing, leading to poor impurity removal. The fact that both PET and water are polar further exacerbates this effect.

[0017] High flow rates and turbulence of the washing liquid on the surface can be achieved by the possibility of direct contact with the surface.

[0018] Microorganisms form gelatinous and / or mucous surfaces to some extent, which adhere to the bottle surface as a difficult-to-dissolve coating. Direct contact with the washing liquid and the resulting turbulence facilitate the peeling off of these coatings.

[0019] However, the presence of the structure on the container body makes the adhesion or formation of this coating advantageous.

[0020] Therefore, this structure, namely the protrusions and depressions, is preferably formed in such a way that the container can be emptied through the vent points, such that less than 0.5% of the detergent filler adheres to the container after 3 minutes of initial emptying. This ensures that bacteria can be rapidly expelled from the container.

[0021] As mentioned above, this is achieved or facilitated by the accessibility of the surface.

[0022] The remaining amount is preferably less than 0.3%, and more preferably less than 0.1% of the filling amount.

[0023] The recesses and ribs surrounding them give the container greater rigidity. Therefore, the container can be formed with significantly lower wall thicknesses, reducing material consumption. The formation of the recesses and ribs surrounding them makes them visible from the container opening, and correspondingly, allows for the application of a washing liquid jet (followed by a water jet) from the container opening, ensuring that the reusable plastic container can be thoroughly rinsed without additional expense, thus enabling its reuse in the food industry.

[0024] Preferably, at least 95% of the surface of the recesses and ribs is visible from the container opening.

[0025] This increases the surface area that can be directly contacted by the water jet.

[0026] Particularly preferably, at least 98% of the surface of the recesses and ribs is visible from the container opening.

[0027] This further improves the efficiency of the washing process.

[0028] In a particularly preferred embodiment, the surfaces of the recesses and ribs are fully visible from the container opening.

[0029] Therefore, turbulence can be generated on the entire surface inside the container throughout the washing process.

[0030] Designing a repeating structure as a honeycomb structure results in exceptionally high stiffness and / or insensitivity to external forces. A honeycomb structure is composed of multiple hexagonal elements arranged in series.

[0031] The honeycomb structure is preferably arranged such that two opposite sides of the hexagons extend substantially along, or in the direction of, the longitudinal axis of the reusable plastic container. Thus, two adjacent sides of the hexagons form ribs inclined along the longitudinal axis. This facilitates the drainage of washing liquid.

[0032] The honeycomb structure has a cell size between 10mm and 35mm. This size corresponds to the longest extension of the cell, in other words, the distance between two opposite corners.

[0033] This size of honeycomb has proven to have high rigidity. The area surrounded by the honeycomb is small enough to avoid dents, but also large enough to avoid giving the impression of a textured surface in which all the cells can deform into each other.

[0034] Preferably, the recesses in the honeycomb structure have a depth between 3 mm and 8 mm.

[0035] This ensures that the cell structure is relatively flat and that the surface can be well accessed from the container opening.

[0036] Preferably, the transition from the rib to the recess has a radius greater than 1 mm, particularly greater than 1.5 mm. However, these radii preferably do not exceed 3 mm.

[0037] As a result, the transition is not a sharp edge, and the liquid adhering to the transition area can flow without obstruction.

[0038] Another aspect of the invention relates to a reusable plastic container, comprising a container body, a container bottom, and a container opening positioned opposite the container bottom. A groove is formed on the container body at an angle of 0° to 30° to the horizontal plane. At least 90% of the surface of the groove is visible from the container opening.

[0039] This formation of the container body can serve as a supplement to or alternative to the formation already described.

[0040] These grooves are also depressions in the sense of this description.

[0041] Similar to the repeating structures described earlier, these help increase the rigidity of plastic containers.

[0042] Since at least 90% of the surface of the groove is visible from the container opening, the washing liquid can be applied directly to the corresponding surface from the container opening.

[0043] The effect achieved by this arrangement corresponds to the effect previously described regarding repeating structures. Therefore, at least 95%, preferably 98%, of the surface of the container opening is visible, particularly the entire recess.

[0044] As the rigidity of the container increases, the wall thickness can be reduced, at least within a certain range.

[0045] The groove can have a width of 1mm to 9mm.

[0046] This results in higher stiffness compared to containers without grooves.

[0047] The grooves can have a depth of 1mm to 6mm. The maximum depth ensures that impurities in the grooves do not adhere too firmly, and the washing liquid can be drained easily accordingly.

[0048] Preferably, the transition from the groove to the container body has a radius greater than 1 mm, particularly greater than 1.5 mm. However, these radii preferably do not exceed 3 mm.

[0049] As a result, the transition is not a sharp edge, and the liquid adhering to the transition area can flow without obstruction.

[0050] Reusable plastic containers can have an average wall thickness between 0.3 mm and 0.6 mm in the area of ​​the container body.

[0051] This corresponds to a significant reduction in the traditional container body of a reusable plastic container without recessed elements, which in turn results in a lighter weight relative to traditional reusable plastic containers.

[0052] Preferably, the reusable plastic container is made of materials from the list including PET, PEN, PLA, PEF, PE, PP or mixtures thereof.

[0053] The aforementioned materials, particularly PET or PEF, have a viscosity of 0.7 dl / g to 1.1 dl / g, preferably up to 0.9 dl / g. The viscosity is measured at the input particle level according to ASTM D4603 prior to the manufacture of the preform.

[0054] Surprisingly, it has been found that, particularly for PET, lower viscosity is advantageous, contrary to the popular theory of using PET with high viscosity, because in this case the surface can be imaged accordingly accurately, and thus the grooves and ribs can be imaged precisely.

[0055] Preferably, copolymers are selected as materials from a list of copolymers containing 0.5% to 3% IPA, CHDM, FDCA or DEG.

[0056] Preferably, the PET material contains isophthalic acid (IPA) of greater than 1.5% by mass, particularly PET material containing IPA of greater than 2% by mass and diethylene glycol (DEG) of greater than 0.5% by mass, particularly PET material containing more than 1% by mass. However, the sum of IPA and DEG is still less than 5% by mass, particularly less than 4% by mass.

[0057] In particular, the addition of IPA and / or DEG allows for the fabrication of thicker-walled preforms because these additives slow down crystallization behavior. Furthermore, these additives can lower the melting temperature.

[0058] Preferably, the reusable plastic container is formed in such a way that the grooves or repeating structures of the reusable plastic container are reinforced in such a way that a point force of 30 N / cm² will not cause permanent plastic deformation. The force is applied to the plastic container for 5 minutes.

[0059] This ensures that reusable plastic containers do not deform when used correctly.

[0060] Preferably, the reusable plastic container is formed in such a way that the number of colony-forming units (CFU) after the washing process is less than 30, particularly less than 10.

[0061] To determine this quantity, we used a test method from the International Society for Beverage Technology (ISBT). These test methods were published in 2004 under the title "Microbiological Testing Methods, Second Edition." According to this publication, Procedure 10 is used for the microbiological testing of membrane-filtered packaging containers.

[0062] Adhering to these requirements ensures that each reusable plastic container can be safely refilled.

[0063] Reusable plastic containers can be formed by creating both a honeycomb structure in segments and additional grooves on the container.

[0064] The grooves allow the honeycomb and non-honeycomb structures to be separated from each other, and also increase the rigidity of the reusable plastic container.

[0065] Reusable plastic containers can have a volume ranging from 200ml to 3000ml.

[0066] Preferably, the reusable plastic container is made from a preform produced by a stretch blow molding process.

[0067] The preform has a generally elongated preform body and is designed to be closed at its longitudinal ends. The injection point, typically generated by injection molding, is also located here. Attached to the other end of the preform body is a neck portion, which has a pouring spout. The neck portion already has the later shape of a container neck. In many known preforms, the preform body and neck portion are separated from each other by a so-called support ring. The support ring projects radially from the neck wall and is used for transporting the preform or the plastic container made from it, and for supporting the preform at the blow mold or supporting the plastic container when it is closed with a cap.

[0068] After the preform is manufactured, it is demolded and can be further processed immediately while still hot in a single-stage stretch blow molding method. In a two-stage stretch blow molding method, the preform is cooled and temporarily stored on a stretch blow molding apparatus to allow for further processing in a spatially and / or temporally separate manner. Before further processing in the stretch blow molding apparatus, the temperature of the preform is adjusted as necessary, that is, the preform is made to exhibit a temperature profile. The preform is then introduced into the blow mold of the stretch blow molding apparatus. In the blow mold, the preform is finally inflated according to the mold cavity by using overpressure blown gas (usually air), and the preform is additionally axially stretched using a stretch mandrel.

[0069] An injection molding method is also known in which stretch blow molding is performed directly after the injection of a preform. The preform is held on an injection core, which simultaneously forms a type of stretch mandrel. The preform is then pressurized again by overpressure through the cavity of a blow mold (either by sending the blow mold to the injection core or vice versa), and the preform is stretched by the stretch mandrel. The resulting plastic container is then demolded. Stretch blow-molded or injection blow-molded plastic containers can be identified by the injection point, typically located in an area at the bottom of the container, created by the preform. At this injection point, the plastic material is stretched only slightly or not at all. Attached Figure Description

[0070] Based on the schematic drawings, embodiments of the present invention will now be explained in more detail. In the drawings:

[0071] Figure 1 A reusable plastic container is shown;

[0072] Figure 2 Detailed views of the structure are shown;

[0073] Figure 3 A cross-section through the structure is shown;

[0074] Figure 4 It shows crossing Figure 1 A cross-sectional view of a reusable plastic container;

[0075] Figure 5 It shows crossing Figure 1 Another cross-sectional view of a reusable plastic container;

[0076] Figure 6 It shows something similar to passing through a reusable alternative plastic container. Figure 2 A cross-sectional view of the cross-section. Detailed Implementation

[0077] Figure 1 A reusable plastic container 100 is shown. The reusable plastic container 100 has a container body 20, a container bottom 10, and a container opening 30. The container opening 30 is arranged relative to the container bottom 10.

[0078] The container body 20 is substantially cylindrical between the container bottom 10 and the conical container shoulder 31. Multiple elements forming the repeating structure 21 are arranged in this area. In this example, it is formed in the form of a honeycomb structure. The repeating structure 21 is formed by recesses 22 and ribs 23 surrounding the recesses 22.

[0079] In this example, the honeycomb structure is arranged such that its longest extension, the connection of two opposite corners, extends towards the vertical axis X. Therefore, the two opposite sides of the honeycomb lie in the direction of the vertical axis X.

[0080] As a result, two adjacent sides of the hexagon form ribs that are inclined to each other in the direction toward the container opening 30 and also toward the container bottom 10.

[0081] The liquid in the container can simply flow and / or drain along these ramps.

[0082] Figure 2 An enlarged view of a portion of the container body 20 or a repeating structure 21 located on the container body 20 is shown. Figure 2 A single recess 22 and a rib 23 surrounding the recess 22 are shown. At the center of this recess is an outward protrusion 24.

[0083] In this example, recess 22 is formed as a hexagonal honeycomb. Its maximum length dimension A3 is 24 mm. The width A4 of the honeycomb between the two parallel sides is 21.7 mm.

[0084] Depression 22 with radius R1 (see Figure 3 It enters the rib 23 adjacent to the recess 22. Between the radius R1 of the first transition and the radius R1 of the second transition, there is a region at the rib 23 that holds the surface of the container body 20, which has a width A5 of 1.2 mm.

[0085] Figure 3 It shows Figure 2 The cross-section AA is shown. The recess 22 is shown in the cross-section. The cross-section shown here is substantially rotationally symmetric about the Z-axis. The recess 22 has a depth A2 of 3.4 mm. In the region of the protrusion 24, the depth A1 is approximately 2.6 mm.

[0086] Figure 4 It shows the process along the rinsing line Figure 1 The line BB passes through Figure 1 A cross-sectional view of a reusable plastic container 100.

[0087] The jets S1 to S4 provide visibility of the recess 22 starting from the container opening 30. By definition, the starting point is the center of the container opening 30. It can be seen that the area of ​​the recess 22 located at the top in this illustration, starting from the inlet opening 30, is not visible. However, the remaining surface of the recess 22 is visible from the container opening 30, and a corresponding water jet can be applied from the container opening 30.

[0088] In other words, only a small area above the two sides of the hexagon cannot enter through the container opening 30. However, the other four sides of the hexagon and the entire surface can be sprayed directly with water jets from the container opening 30.

[0089] This also applies to rib 23 surrounding recess 22 (see also) Figure 2 The application of rib 23 at Figure 5 and Figure 4 This is most evident in the middle. The following section will provide a comprehensive description of these issues based on this aspect.

[0090] Figure 5 It also shows crossing Figure 1 A cross-sectional view of a reusable plastic container, but with... Figure 4 The cross-section is slightly distorted compared to the others. Figure 5 The cross section through Figure 1 The line CC shown extends. Therefore, the cut extends to the bevel of recess 22. The visibility of rib 23 and recess 22 is shown by jets S1 to S4, similar to... Figure 4 .

[0091] like Figure 4 As shown, a portion of the ribs 23 are vertically aligned, thus extending in the direction of the water jet injected from the container opening 30 into the reusable plastic container. During operation, these are entirely water-dependent. The sloping sides of the recess 22, although partially shaded and visible from the container opening 30, are only a small portion. This portion is shaded, therefore not directly exposed to water during operation. However, this effect is mitigated by the sloping nature of these sides.

[0092] When a water jet directly impacts the surface to be cleaned, it creates turbulence, which can actually tear off the surface coating.

[0093] Figure 6 A reusable alternative plastic container 100 similar to the one shown is shown. Figure 2 A cross-sectional view of the cross-section.

[0094] This reusable plastic container 100 has multiple horizontal grooves 40, two in this example. The visibility from the container opening 30 is also illustrated by the jetting, not specified herein. The side of the groove 40 facing the container opening 30 is fully visible from the opening 30, and a water jet can be applied accordingly during washing or rinsing. Only certain areas of the surface in the shadow of the grooves 40 are not directly in contact with water. However, because these areas are small, the water flow is still turbulent even in these areas. Therefore, the coating located in these areas can also be easily removed.

[0095] Figure 6The groove 40 is 4.2 mm wide and 1.2 mm deep. The groove enters the surface of the container body with a radius of 1.5 mm.

[0096] Compared to existing technologies, the reusable plastic container 100 described in this example has a significantly lighter weight. However, it can be cleaned as easily and effectively as known reusable containers. Due to the arrangement of the structure, as suggested, the rigidity of the bottle can be increased, while due to its special shape, the bottle remains easy and effective to clean.

[0097] Of course, they can also be combined into the elements described in a single embodiment.

Claims

1. A reusable plastic container (100), comprising a container body (20), a container bottom (10), and a container opening (30) positioned relative to the container bottom, wherein, The container body (20) is provided with a repeating honeycomb structure formed by recesses (22) and ribs (23) surrounding the recesses (22), wherein the recesses are deformations toward the interior of the plastic container, characterized in that at least 90% of the surface of the recesses (22) and the ribs (23) can be seen from the container opening (30).

2. The reusable plastic container (100) according to claim 1, characterized in that, At least 95% of the surface of the recess (22) and the rib (23) can be seen from the container opening (30).

3. The reusable plastic container (100) according to claim 1, characterized in that, At least 98% of the surface of the recess (22) and the rib (23) can be seen from the container opening (30).

4. The reusable plastic container (100) according to claim 1, characterized in that, The surfaces of the recess (22) and the rib (23) are fully visible from the container opening (30).

5. The reusable plastic container (100) according to any one of claims 1 to 4, characterized in that, The honeycomb structure (21) has a honeycomb size between 10 mm and 35 mm.

6. The reusable plastic container (100) according to any one of claims 1 to 4, characterized in that, The recesses (22) of the honeycomb structure (21) have a depth between 3 mm and 8 mm.

7. The reusable plastic container (100) according to any one of claims 1 to 4, characterized in that, The transition from the rib (23) to the recess (22) has a radius greater than 1 mm.

8. The reusable plastic container (100) according to claim 7, characterized in that, The radius is greater than 1.5 mm.

9. The reusable plastic container (100) according to claim 1, wherein, A groove (40) is formed on the container body (20) at an angle of 0° to 30° with respect to the horizontal plane, characterized in that at least 90% of the surface of the groove (40) is visible from the container opening (30).

10. The reusable plastic container (100) according to claim 9, characterized in that, The groove (40) has a width of 1 mm to 9 mm.

11. The reusable plastic container (100) according to claim 9 or 10, characterized in that, The groove (40) has a depth of 1 mm to 6 mm.

12. The reusable plastic container (100) according to claim 9 or 10, characterized in that, The transition from the groove (40) to the container body (20) has a radius greater than 1 mm.

13. The reusable plastic container (100) according to claim 1 or 9, characterized in that, The reusable plastic container (100) has an average wall thickness between 0.3 mm and 0.6 mm in the area of ​​the container body.

14. The reusable plastic container (100) according to claim 1 or 9, characterized in that, The reusable plastic container (100) is made of materials from a list including PET, PEN, PLA, PEF, PE, PP or mixtures thereof.

15. The reusable plastic container (100) according to claim 14, characterized in that, The viscosity of the material is 0.7 to 1.1 dl / g, as measured at the input particle level according to ASTM D4603.

16. The reusable plastic container (100) according to claim 14, characterized in that, Select copolymers as materials from a list of copolymers containing 0.5% to 3% IPA, CHDM, FDCA, or DEG.

17. The reusable plastic container (100) according to claim 1, characterized in that, The reusable plastic container (100) is reinforced by the honeycomb structure (21) in such a way that a point force of 30 N / cm2 will not cause plastic deformation.

18. The reusable plastic container (100) according to claim 1 or 9, characterized in that, The number of colony-forming units (CFU) after the washing process is less than 30.

19. The reusable plastic container (100) according to claim 9, characterized in that, The honeycomb structure and the grooves (40) are formed in segments on the container body (20).

20. The reusable plastic container (100) according to claim 1 or 9, characterized in that, It has a volume ranging from 200ml to 3000ml.

21. The reusable plastic container (100) according to claim 1 or 9, characterized in that, It is made from a preform produced by a stretch blow molding process.

22. The reusable plastic container (100) according to claim 12, characterized in that, The radius is greater than 1.5 mm.

23. The reusable plastic container (100) according to claim 15, characterized in that, According to ASTM D4603, the viscosity of the material is as high as 0.9 dl / g, as measured at the input particle level.

24. The reusable plastic container (100) according to claim 18, characterized in that, The number of colony-forming units (CFU) after the washing process is less than 10.

25. The reusable plastic container (100) according to claim 9, characterized in that, The reusable plastic container (100) is reinforced by the groove (40) in such a way that a point force of 30 N / cm2 will not cause plastic deformation.

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