Hinged closure
By employing a two-component injection molding process and injection mold design, the problem of insufficient material properties of PCR plastic in hinged closures was solved, enabling the production of hinged closures with high functionality and a high proportion of PCR plastic, and allowing for visualization of PCR plastic usage.
Patent Information
- Application Number
- CN202480023856.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2023-04-14
- Filing Date
- 2024-04-11
- Publication Date
- 2025-11-04
Smart Images
Figure CN120897878A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The invention relates to a hinge closure according to the preamble of claim 1, to a method according to claim 12, and to an injection mold according to the preamble of claim 14.
[0002] STATE OF THE ART Hinge closures are generally understood to be closures having a cap and a hingedly connected hinge lid to the cap. The hinge lid can be pivoted or snapped between two positions, namely a closed position and an open position. To achieve this functionality, it is known to use two tension bands and a central connecting piece to form the hinged connection between the cap and the hinge lid. The joint achieved by the two tension bands and the central connecting piece thus exhibits a living behavior, in which the hinge lid automatically opens and closes when a defined limit is exceeded.
[0003] However, living hinges require specific material properties, since the elasticity of the plastic used is not sufficient. Otherwise, the tension bands would be overstretched and the living nature of the hinge closure would be lost. In the state of the art, polypropylene is preferably used to produce hinge closures as described above.
[0004] Since PCR (post-consumer recycled) plastics are used in many areas for the production of containers, it is desirable to be able to also use PCR materials for the production of hinge closures. However, post-consumer recycled plastics do not have the material properties required to provide a living hinge.
[0005] Object of the invention The described disadvantages of the state of the art lead to the object of producing a hinge closure that can use PCR plastics.
[0006] Description The described object for flip-top closures is achieved by the features mentioned in the characterizing part of claim 1. The dependent claims relate to developments and / or advantageous alternative embodiments.
[0007] The invention is preferably characterized in that the hinge lid, the joint, the retaining skirt and at least a first part of the cover plate are injection molded from a first plastic, and at least the housing is injection molded from a second plastic, and the first plastic and the second plastic are integrally bonded to one another at their transition. The dual-component design of the hinge closure means that only those elements of the hinge closure that require the functionality of virgin plastic are injection molded from a first virgin plastic. Other parts can be injection molded from a second, cheaper plastic, in particular a PCR plastic. After the dual-component injection molding process, the two plastics flow into one another or fuse together, whereby they are reliably integrally bonded in the injection mold and can no longer be separated.
[0008] In a particularly preferred embodiment of the application, the second plastic is a post-consumer recycled (PCR) plastic. This allows the areas of the hinge closure for which the requirements on the plastic properties are lower (the shell and a part of the cover plate) to be made from recycled plastic.
[0009] Suitably, the first plastic is a virgin non-recycled plastic which fulfils all material properties of the hinge closure, in particular for the living hinge and the retaining skirt which can be snapped onto the container. Polypropylene has proven to be a suitable virgin plastic.
[0010] Advantageously, the first part of the cover plate is dimensioned such that the retaining skirt is located within the first part and the hinge is located directly adjacent to the first part. This means that the first part of the cover plate, which has to be made of virgin plastic due to the retaining skirt underneath, is as small as possible and the second part of the cover plate can be injection molded from PCR plastic.
[0011] In another preferred embodiment of the application, the cover plate has a second part which surrounds the first part. This means that the second part is as large as possible and is integrally bonded to the first part.
[0012] Advantageously, the second part of the cover plate is injection molded from the second plastic, whereby as large a proportion of the hinge closure as possible can be made from inexpensive PCR plastic.
[0013] In another preferred embodiment of the application, the first part and the second part of the cover plate are integrally bonded to one another at their point of contact. For this purpose, a two-component injection molding process is used. At their transition, the two plastics fuse together, resulting in an insoluble bond. Furthermore, the connection can be form-fitting or frictional.
[0014] It has proven to be advantageous if the first plastic has a first color and the second plastic has a second color which is different from the first color. This can give the consumer a visual indication of the use of PCR plastic and explicitly indicate how much recycled plastic has been used to produce the hinge closure.
[0015] Suitably, the hinge is implemented by two tension straps and a central link, the first ends of the two tension straps and the central link being formed on the shell and their second ends being formed on the hinged cover. Here, the length of the tension straps and the central link is dimensioned such that the hinge is living and the hinged cover is fixed in both the open position and the closed position. This living hinge is referred to as a butterfly hinge.
[0016] In a preferred embodiment of the application, the first plastic consists of virgin HDPE or virgin PP. In principle, virgin polypropylene is preferred for the reliable functioning of the living hinge; however, there are already solutions with functional hinges made of high-density polyethylene.
[0017] In another particularly preferred embodiment of the application, the second plastic consists of PCR-HDPE or PCR-PP. This means that surprisingly, as large a proportion as possible of the hinge closure can be made from recycled plastic without limiting or impairing the functionality of the hinge closure. In principle, PCR-PP is used for the second plastic if the first plastic is virgin PP, and PCR-HDPE is used for the second plastic if the first plastic is virgin HDPE. However, a combination of HDPE and PP is also not excluded in the context of the application.
[0018] Another aspect of the application relates to a method for producing a hinge closure. In the method, in an injection mold having a mold, a mold core, and a cavity formed between the mold and the core, which cavity constitutes a negative impression of the hinge closure, a first core retraction insert and a second core retraction insert are retracted into a front position and abut the mold core sealingly, thereby preventing the filling of the cavity with at least a first part of the hinge lid, the joint, the retaining skirt, and the lid plate. An accessible area of the cavity, which at least forms a housing of the hinge closure, is filled with a second molten plastic. Thus, at least the housing and optionally a second part of the lid plate are injection molded. Then, the first core retraction insert and the second core retraction insert are retracted into a rear position, and the unfilled part of the cavity is filled with a first molten plastic, thereby injection molding the hinge lid, the joint, the retaining skirt, and at least the first part of the lid plate and optionally the entire lid plate. The first plastic and the second plastic are integrally bonded to one another at their common point of contact, and the solidified two-component hinge closure is ejected from the injection mold. The first core retraction insert serves as an injection molding core for the first part of the lid plate when in the front position. The second core retraction insert closes off the passage for filling the cavity of the hinge lid when in its front position. The core retraction inserts, which are also referred to as sliders or closing sliders, allow the production of two-component hinge closures in which the elements that require virgin plastic are precisely separated from the elements that can be produced with PCR plastic.
[0019] Another aspect of the application relates to an injection mold for producing a hinge closure, the injection mold having a first core retraction insert and a second core retraction insert, which are movable between a front position and a rear position and prevent the filling of the cavity of at least a part of the hinge lid, the joint, the retaining skirt, and the lid plate when in their front position. This allows the cavity of the housing and a second part of the lid plate to be injection molded first with PCR plastic. Thus, all the elements that are suitable for recycled plastic are made from PCR plastic.
[0020] In another preferred embodiment of the application, the first core retract insert in the front position sealingly abuts the mold core. Thus, the cavity of the first part of the cover plate is reliably sealed and the second plastic cannot penetrate into the cavity which is intended to be filled with the first plastic.
[0021] It is particularly preferred if the second core retract insert, in the front position, closes the passage between the cavity of the cap and the cavity of the hinged lid and, in the rear position, opens said passage. This allows the hinged lid and the joint to be injection molded in particular with the first plastic, without the second plastic penetrating into the cavity of the joint and the hinged lid in advance.
[0022] Further advantages and features will become apparent from the following description of embodiments of the application with reference to the schematic drawings. In the drawings, in which the schematic drawings are not drawn to scale: Figure 1 is a first isometric view of a hinged closure with an open hinged lid, seen from the front at an angle; Figure 2 is a second isometric view of the hinged closure, seen from the back at an angle; Figure 3 is an axonometric view of the hinged closure with the hinged lid closed; and Figure 4 is an axonometric sectional view of the hinged closure with first and second customized core retract inserts.
[0023] Figures 1 to 4 A hinged closure is shown, which is designated as a whole by the reference 11 and is produced in an injection mold. The closure 11 has a cap 13 which can be fixed to the neck of a container and a hinged lid 15 which is hingedly connected to the cap. The cap 13 can be screwed onto the container neck, for example, or can be latched onto the container neck.
[0024] The cap 13 has a shell 17, a cover plate 19 directly adjacent to the shell 17 and a retaining skirt 20 projecting from the inner side of the cover plate 19. By means of the retaining skirt 20, the hinged closure 11 can be screwed or latched onto a container. The retaining skirt 20 thus has an internal thread or a latching element on its inner side. A dispensing opening 21 is provided in the cover plate 19 to enable the contents of the container to be dispensed.
[0025] The hinged lid 15 is connected to the cap 13 by means of a joint 22. A sealing joint 23 is provided on the inner side of the hinged lid 15, which sealing joint interacts sealingly with the dispensing opening 21 when the closure 11 is closed. The hinged lid 15 can be pivoted via the joint 22 between a closed position and an open position and is latched in position when in both positions.
[0026] The joint can be realized by two tension bands 25a, 25b and a central connecting piece 27. The first ends of the tension bands 25a, 25b and the central connecting piece 27 are formed on the housing 17 and their second ends are integrally formed on the hinged lid 15. The interaction of the tension bands 25a, 25b and the central connecting piece 27 enables the hinged lid 15 to be latched into the open and closed position. Thus, the joint automatically opens and closes when a defined tension is exceeded, thus exhibiting a living behavior.
[0027] The hinged lid 15, the joint 22, the retaining skirt 20 and at least the first portion 29 of the cover plate 19 are injection molded from a first plastic. Preferably, this plastic is virgin, non-recycled plastic, as only such plastics meet the high functional requirements of the parts of the hinged closure described above, in particular the living joint 22.
[0028] At least the housing 17 is injection molded from a second plastic. The cover plate 19 can consist entirely of the first plastic. However, it is preferred that a second portion 31 of the cover plate is injection molded from the second plastic. The second plastic is preferably a post-consumer recycled (PCR) plastic. This means that the hinged closure can be partially made of PCR plastic, wherein exactly the parts of the hinged closure with lower material requirements are injection molded from PCR plastic. Thus, the hinged closure 11 has a flawless joint function and still contains the largest possible proportion of PCR plastic. In order to maximize the proportion of PCR plastic, the size of the second portion 31 is as large as possible. However, a limit is set by the diameter of the retaining skirt 22. In order for the retaining skirt to be made of the first plastic, the first portion 29 must at least have the diameter of the retaining skirt.
[0029] The first plastic and the second plastic merge together at their transition or at the point of contact of the first portion 29 and the second portion 31. The line of contact 32 is partially shown in Figure 1 and Figure 2 It is understood that the first plastic and the second plastic can have different colors. This allows to clearly show the consumer how large the proportion of PCR plastic is in the hinged closure according to the invention.
[0030] The hinged closure 11 is produced in an injection mold which has a mold, a mold core and a cavity formed between the mold and the core in a known manner. The cavity constitutes a negative mold of the hinged closure.
[0031] The injection mold is equipped with a first core retraction insert 33 and a second core retraction insert 35, which can be moved between a front position and a rear position. In the front position, the first core retraction insert 33 sealingly abuts the mold core. In the front position, the second core retraction insert 35 closes the passage between the cavity of the cap 13 and the cavity of the hinged lid 15. In the rear position, the second core retraction insert 35 opens the passage.
[0032] When both core retraction inserts 33, 35 are in the front position, filling of the cavity of at least the first part 29 of the hinged lid 15, the joint 22, the retaining skirt 20 and the cover plate 19 is prevented. The accessible area of the cavity is filled with PCR plastic and the housing 17 and preferably the second part 31 of the cover plate 19 is injection molded. Thus, as large a proportion of the hinged closure as possible is made of PCR material.
[0033] After the two core retraction inserts are retracted into the rear position, the unfilled part of the cavity is filled with first molten plastic, thereby injection molding the hinged lid, the joint, the retaining skirt and at least the first part 29 of the cover plate 19. Through the open passage opened by the second core retraction insert 35, the first plastic can fill the joint 22 and then flow via the passage into the cavity of the hinged lid 15.
[0034] The first plastic and the second plastic are combined using a two-component injection molding process, in which the two plastics flow into one another and form an integral bond. A positive fit or frictional connection through a specially designed transition of the plastic transition is also conceivable.
[0035] Finally, the two-component hinged closure is demolded from the injection mold.
[0036] A first step 37a and a second step 37b can be formed on the edge of the cover plate 19. The hinged lid, when in its closed position, is received in a recess 39 formed between the first step 37a and the second step 37b. The hinged lid is well protected between these steps against accidental opening.
[0037] In principle, PP is preferred for the joint, as it is less elastic than HDPE. However, hinged lids for HDPE have also been developed. Thus, both PP and HDPE are conceivable for the PCR plastic (second plastic) and the virgin plastic (first plastic). A mixture of PP and HDPE (e.g. virgin PP and PCR-HDPE) is also not excluded.
[0038] List of reference signs: 11 hinged closure 13 cap 15 hinged lid 17 housing 19 cover plate 20 retaining skirt 21 dispensing opening 22 joint 23 sealed joint 25a, 25b tensioning band 27 central connection 29 first portion of the cover plate 31 second portion of the cover plate 32 contact wire 33 first core retraction insert 35 second core retraction insert 37 first and second steps 39 recess
Claims
1. A hinge closure (11) which is injection molded from plastic and has - a cap (13) which can be fixed to the neck of a container and which has a housing (17), an immediately adjacent cover plate (19), a retaining skirt (20) which protrudes from the inner side of the cover plate (19), and a dispensing opening (21) which is provided on the cover plate (19), and - a hinge lid (15) which is connected to the cap (13) by means of a joint (22) and which has a sealing joint (23) provided on its inner side, the hinge lid (15) being pivotable by means of the joint (22) between a closed position and an open position and being latched into both positions, characterized in that the hinge lid (15), the joint (22), the retaining skirt (20), and at least a first portion (29) of the cover plate (19) are injection molded from a first plastic, and at least the housing (17) is injection molded from a second plastic, and the first plastic and the second plastic are integrally bonded to one another at the transition of the first plastic and the second plastic.
2. The closure of claim 1 wherein, The second plastic is a post-consumer recycled (PCR) plastic.
3. A closure as claimed in claim 1 or 2, characterised in that The first plastic is a virgin, non-recycled plastic.
4. A closure as claimed in any one of the preceding claims, characterised in that, The first portion (29) of the cover plate (19) is dimensioned such that the retaining skirt (20) is located within the first portion (29), and the joint (22) is adjacent to the first portion (29).
5. A closure as claimed in any one of the preceding claims, characterised in that, The cover plate (19) has a second portion (31) which surrounds the first portion (29).
6. The closure of claim 5, wherein The second portion (31) of the cover plate (19) is injection molded from the second plastic.
7. A closure as claimed in claim 5 or 6, characterised in that The first and second portions (29, 31) of the cover plate (19) are integrally bonded to one another at their point of contact (32).
8. A closure as claimed in any one of the preceding claims, characterised in that, The first plastic has a first color, and the second plastic has a second color which is different from the first color.
9. A closure as claimed in any one of the preceding claims, characterised in that, The joint (22) is realized by two tension straps (25a, 25b) and a central connecting piece (27) having a length and a width, the first ends of the two tension straps and the central connecting piece being integrally formed on the housing (17), and the second ends of the two tension straps and the central connecting piece being integrally formed on the hinge lid (15).
10. A closure as claimed in any one of the preceding claims, characterised in that, The first plastic consists of virgin HDPE or virgin PP.
11. A closure as claimed in any one of the preceding claims, characterised in that, The second plastic consists of PCR-HDPE or PCR-PP.
12. A method for producing a hinge closure according to any one of the preceding claims, characterized in that in an injection mold having a mold, a mold core, and a cavity formed between the mold and the core, the cavity constituting a negative mold of the hinge closure, - a first core retraction insert (33) and a second core retraction insert (35) are retracted into a front position and sealingly abut the mold core, thereby preventing filling of the cavity with the hinge lid, the joint, the retaining skirt, and at least the first portion of the cover plate. - the accessible area of the cavity is filled with the molten second plastic, thereby injection molding at least the shell (17) and optionally a second part (31) of the cover plate (19), the accessible area of the cavity forming at least the shell of the hinge closure, - the first and second core retract inserts (33, 35) are retracted to a rear position, and - the unfilled part of the cavity is filled with the molten first plastic, thereby injection molding the hinge lid (15), the joint (22), the retaining skirt (20) and at least a first part (29) of the cover plate (19), and optionally the entire cover plate (19), and - the first and second plastics are integrally bonded to each other at their common point of contact, and - the solidified two-component hinge closure (11) is ejected from the injection mold.
13. The method of claim 12, wherein, Immediately after injection of the second plastic, the two core retract inserts (33, 35) are moved to the rear position, and for integrally bonding, immediately after the two core retract inserts (33, 35) are in the rear position, the first plastic is injected onto the still hot second plastic.
14. An injection mold for producing a hinge closure according to claims 1 to 10, the injection mold having a mold, a mold core and a cavity formed between the mold and the core, the cavity constituting a negative mold of the hinge closure, further characterized in that a first core retract insert (33) and a second core retract insert (35) are movable between a front position and a rear position and prevent filling of the cavity with the hinge lid, the joint, the retaining skirt and at least a part of the cover plate when in their front position.
15. The injection mold of claim 14, wherein, The first core retract insert (33) sealingly abuts the mold core when in the front position.
16. Injection mold according to claim 14 or 15, characterized in that The second core retract insert (35) closes a passage between the cavity of the cap and the cavity of the hinge lid when in the front position and opens the passage when in the rear position.