A plastic tethered cap for a container and production method

Abstract

The invention introduces a plastic container cap featuring a cylindrical cap base, a retention ring connected by a rupture bridge, and a fixator. The tethers, incorporating rupture lines at their bottoms, enable the cap's detachment while remaining linked to the retention ring. Upon full opening, the tethers function as a torsion bar, allowing the fixator to exert force, ensuring stable retention in the open position. A key innovation is the fixator's tongue with curved rupture line according to the shape of the tongue. This unique design not only facilitates easy cap opening and closing on a container by reducing resistance but also ensures stable locking after the container is opened.

Description

FIELD OF THE INVENTION

[0001] The present invention is related to a container cap and manufacturing method. More specifically, the invention concerns a cap designed with a retaining ring for attachment to a container neck, this cap includes a connecting element that remains securely attached to the retaining ring after the cap has been opened.BACKGROUND OF THE INVENTION

[0002] The cap is particularly, but not exclusively, suitable for beverage bottles, especially intended for water or soft drinks. The cap is designed to secure in the open position, preventing it from obstructing the user during cap opening and closing.

[0003] Prior art caps for bottles typically consist of a cap with an inner thread designed to engage with the outer thread of the bottle's neck. Additionally, these caps include a security ring connected to the cap through a tear line, equipped with breakable elements like bridges.

[0004] In many regions, the regulatory authorities have mandated to reduce environmental pollution caused by loose caps. According to regulations (SUP - Directive (EU) 2019 / 904), plastic caps are permitted for sale only if they remain securely attached to the corresponding containers throughout the use stage of the products. Ensuring compliance with regulations SUP - Directive (EU) 2019 / 904), is essential for businesses to avoid fines and fulfill corporate responsibility, with the tethered cap design serving as a sustainable solution aligned with environmental (circular economy) goals.

[0005] The objective of the present invention is to provide a cap for a container meeting industry standards and regulations. Therefore, the innovation focuses on developing a design that enhances the attachment of plastic caps to containers, offering a reliable solution and comfortable during use. By achieving this objective, the invention aims to contribute to the production of plastic caps that enhance the overall quality of packaged products in the market. The inventive solution seeks to provide a reliable and efficient means of securing plastic caps during the products' intended use.

[0006] In document EP3877281 (A1) is described a cap (1) for a container (2), a combination of a closing cap for a container and a neck of the container and a relative method for making the cap for the container. The cap comprises a lateral wall extending about an axis and a transversal wall positioned at one end of the lateral wall, a separation line being provided on the lateral wall to define a retaining ring, which is configured to remain anchored to a neck of the container and which extends up to a free edge; a closing element (302) removably engageable with the neck, so as to open or close the container; the separation line extends about an axis and being circumferentially interrupted to leave the retaining ring (301) and the closing element joined; wherein the retaining ring comprises a joining portion (305) at which the retaining ring is joined to the closing element; a first connecting band (306), which extends from a first end zone of the joining portion to the retaining portion (303), and a second connecting band (307), which extends from a second end zone of the joining portion, the second end zone being positioned circumferentially on the opposite side to the first end zone; a tab (308), interposed between the first connecting band (306) and the second connecting band (307) and being protruding, or aligned with respect to it, so that, when the closing element is in an open condition and the connecting bands keep the closing element connected to the retaining ring, the tab can rest on the neck (201). Prior art caps incorporating a tether, however, exhibit an additional drawback related to the substantial load on the tab (fixator) during cap opening. Since the fixator must be long enough to ensure that the fixation was stable. This load can lead to fixator deformation and, in extreme cases, even breakage.

[0007] Known invention in document EP3689774 (A1) relates to a container cap having a function of maintaining an open state, the container cap comprising: an indication ring prevented from escaping from a container spout; a cap body screw-coupled to an outer circumferential surface of the container spout; a hinge portion connecting the cap body and the indication ring to each other in a partial section of a circumference of a cut portion disposed between the cap body and the indication ring; and a bridge which connects the cap body and the indication ring at an interval along the circumference of the cut portion and is cut when the cap body is open, wherein: the hinge portion has widthwise opposite edge parts adjacent to opposite cut portions and depressed from the outer side to the inner side thereof, a bending guide groove formed to be integrally connected to the cap body, the indication ring, and the hinge portion, and a protrusion portion having a shape extending and protruding downward from a lower part of the widthwise center thereof; and the indication ring includes a slit formed in a predetermined section of a middle part in a vertical height direction and a concave portion formed therein, wherein the concave portion is disposed at a position corresponding to the protrusion portion, is adjacent to the protrusion portion while being spaced apart therefrom, and is depressed downward. If the fixator is not long enough the fixation in open position is not stable.

[0008] The invention aims to solve an issue in existing caps, particularly regarding the stability of the existing fixator (tab) when opening the cap. The invention aims to make known tethered caps better by making them easier to open and close, and ensuring they stay stable when open.SUMMARY OF THE DISCLOSURE

[0009] To overcome this drawback, caps have been proposed which are provided with a retaining ring, capable of being associated with a bottle's neck, and a closing element tethered to the retaining ring similar to existing caps.

[0010] In accordance with an aspect of the invention, a cap for containers is provided, comprising a substantially cylindrical cap base with a cylindrical wall, a closed top, and an open bottom and with a screw configurated to an outer circumferential surface of the container neck. The retention ring which is configured to remain anchored to a neck of the container and is linked to the bottom edge of the cylindrical cap base through a rupture bridge with breakable points. The cap incorporates a fixator extending downwards from the bottom edge of the cylindrical cap base. Further, in both sides of the fixator the cap comprises a first tethering area of the first tether and a second tethering area of the second tether, extending downwards from a bottom edge of the cylindrical cap, base with the rupture line with rupture bridges through the bottom of both the tethers and fixator. These tethers connect the cap base to a retention ring. The design of the first tether and the second tether enables the removal of the cap base from the container while ensuring its attachment to the retention ring.

[0011] In the cap body's fully open position, the first tether and the second tether serve as torsion bars, allowing the fixator to exert force against the container's neck, thereby retaining the cylindrical cap base in the fully open position.

[0012] The unique characteristic of the invention lies in the fixator, which includes a tongue positioned in the middle of the fixator's bottom part, constituting from 1 / 2 to 1 / 3 of the fixator's width. This feature contributes to the cap's efficient and reliable functioning. The length of each tether may range from 10,5 to 20,5 mm, depending on cap diameter when the diameter is 40,3 mm optimal length of each tether 19,5 mm and with a wide from 1 to 2 mm, with optimal wide of 1,5 mm. And the rupture bridges at a rupture line range from 2 to 8.

[0013] A method for manufacturing tethered plastic caps, comprising the steps of: a) Heating raw plastic material until it reaches a viscous melt state. b) Injecting the melted hot synthetic resin into a closed mold, defining the shape of the tethered cap. c) Allowing the injected material within the mold cavities to cool until it solidifies into a crystallized form. d) Opening the mold and extracting the finished tethered cap. e) Cooling the final product, created with a specially designed configuration, to room temperature.

[0014] This method with the injection molding process as a pivotal means for the mass production of tethered caps using raw materials, and without necessitating additional finishing steps, where the specially designed mold plays a crucial role in defining the shape and characteristics of the tethered caps during the injection molding process.DESCRIPTION OF DRAWINGS

[0015] Fig. 1 is a side view of the cap for a container according to a first embodiment in the closed position. Fig. 2 is a perspective view of the cap for a container according to a first embodiment, in the closed position. Fig. 3 is a side view of the cap for a container with thread visible outside, in the screwed position. Fig. 4 is a side view of the cap for a container, in a closed position. Fig. 5 is a perspective view of one embodiment of a closing cap for a container produced through the manufacturing method of tethered caps utilizing the injection molding process, in the unscrewed position. Fig. 6 is side view of one embodiment of a closing cap for a container produced through the manufacturing method of tethered caps utilizing the injection molding process, inner surface for good demolding, in the unscrewed position with thread visible outside. Fig. 7 is a side view of one embodiment of a closing cap for a container produced through the manufacturing method of tethered caps utilizing the injection molding process, inner surface for good demolding, in the unscrewed position. Fig. 8 is side view of one embodiment of a closing cap for a container produced through the manufacturing method of tethered caps utilizing the injection molding process, inner surface for good demolding, in the unscrewed position, the general parts of the designed tethered ROPP 28 / 18 cap. Fig. 9 is side view of one embodiment of a closing cap for a container produced through the manufacturing method of tethered caps utilizing the injection molding process, inner surface for good demolding, in the unscrewed position, the general parts of the designed tethered ROPP 28 / 36 cap. Fig. 10 is a perspective view of one embodiment of a closing cap for a container produced through the manufacturing method of tethered caps utilizing the injection molding process, inner surface for good demolding, in the unscrewed position, the general parts of the designed tethered ROPP 28 / 36 cap. Fig. 11 is photographic view of the container cap in the unscrewed position according to the first embodiment.

[0016] Examples and embodiments of the invention are more closely described in the following, illustrated by the drawings.DETAILED DESCRIPTION OF THE INVENTION

[0017] To enhance the understanding of the essence and characteristics of the invention, a detailed description is provided for a cap designed to seal a container, specifically a bottle intended to contain a liquid substance such as a beverage. Additionally, the method for manufacturing such caps, along with examples of caps produced using this method, is presented.

[0018] Referring to Figs. 1 to 4, which illustrate the main example of the cap 1 for the container made of plastic in this invention. It can be made in one piece using plastic materials, through injection molding.

[0019] The cap 1 for the container comprises a cap base 2 and a retaining ring 3. The cap base 2 features a circular top panel wall and a cylindrical wall 12 extending downwardly from the peripheral edge of the top panel wall. A circular concavity 13, designed to prevent the formation of a protrusion during injection molding, is present in the center of the upper surface of the top panel wall (Fig. 2). Irregularities, preventing slipperiness, are repeated on the outer peripheral surface of the cylindrical wall 12. The inner peripheral surface of the cylindrical wall 12 features an internal thread with notches spaced in the circumferential direction (Fig. 3).

[0020] The retaining ring 3 is cylindrical as a whole and is connected to the bottom edge of the cylindrical wall 12 of the cap base 2 through rupture line 5 with multiple breakable bridge portions 6 arranged with spacing in the circumferential direction. Each breakable bridge portion 6 is connected to a lower end part of the inner peripheral surface of the cylindrical wall 12, and to an upper end part of the inner peripheral surface of the retaining ring 3.

[0021] The configuration described above in the illustrated cap 1 for the container does not introduce a novel feature to the cap 1 for the container in accordance with the present invention. Cap 1 for the container can adopt a well-known shape, and therefore, a detailed description of this configuration will be omitted here.Example 1

[0022] With further reference to Figs. 1 to 4 and Fig. 11.

[0023] In Fig. 1 can be seen a fixator 10 extending downwards from a bottom edge of the cylindrical cap base 2. A first tethering area of the first tether 4a and a second tethering area of the second tether 4b extending downwards from a bottom edge of the cylindrical cap base 2 at a space 9a, 9b from a fixator 10 on either side thereof, further connecting the cap base 2 to a retention ring 3. The first tether 4a and the second tether 4b are arranged in retaining ring 3 designed with a length of 19,5 mm, a diameter of 1,5 mm, and rupture bridges 8 at a rupture line 7 located at the bottom of both the first tether 4a and the second tether 4b. The fixator 10 extends downwards till the rupture line 7 and comprises a tongue 11 extending where rupture line 7 arranged under it according to the curvature of the tongue 11. The tongue 11 is arranged in the middle of the bottom part of the fixator 10 and is 1 / 3 of the fixator 10 wide. The first tether 4a and the second tether 4b allow the cap base 2 to be removed from the container while remaining attached to the retaining ring 3.

[0024] When the cap base 2 is actuated to a fully open position, the first tether 4a and the second tether 4b act as a torsion bar, allowing the fixator 10 to exert a force against the neck of the container, retaining the cylindrical cap base 2 in the fully open position, wherein the first tether 4a and the second tether 4b lie in a plane substantially parallel to an upper edge of the retention ring 3.

[0025] The fixator 10 and tongue 11 design in this cap 1 with the first tether 4a and the second tether 4b allow for easy removal of the cap base 2 from the container while still being attached to the retaining ring 3. This user-friendly feature enhances the convenience of opening and closing the container. This streamlined and compact design for efficient container closure with a robust and secure closure solution, ensuring ease of use, stability during opening, and retaining cap 2 on the container.

[0026] The tongue 11 of the fixator 10 ensures unobstructed opening of the cap base 2, in same time secure engagement with a neck of the container, enhancing the stability and reliability of the cap base 2 in fully open position.

[0027] In Fig. 4 is shown the dimensions of provided firs example cap 1 which are A: Ø 40,3 mm, B: 15±0,2 mm, C: 10,2 mm.

[0028] A method for manufacturing tethered caps comprising the steps of: a) Heating food-grade High-Density Polyethylene (HDPE) material until it reaches a viscous melt state. b) Injecting the hot HDPE melt into a closed mold, defining the shape of the tethered cap 1, 1a or 1b. c) Allowing the injected HDPE material within the mold cavities to cool until it solidifies into a crystallized form. d) Opening the mold and extracting the finished tethered cap. e) Cooling the final product, created with a specially designed configuration, to room temperature.

[0029] The injection molding process is employed as a pivotal means for the mass production of tethered caps. Examples of such productions are provided.Example 2

[0030] In Fig. 5-7 is shown a cap 18 mm (tethered).

[0031] Fig. 5 A cap 1a tether 4 has projected with a length 14 mm and a diameter 1,5 mm. The tether 4 has 3 rupture bridges. At the center of the top of cap base 2a is located an injection point 13a.

[0032] In Fig. 6 can be seen thread visible outside and its parameter A1 1,3 mm, pinch B1 2,5 mm, thread start B2 1,6 mm, C1 016,1, C2 Ø17,4±0,3 mm, C3 Ø12,8±0,1 mm. Inner surface 15 for good demolding.

[0033] Fig. 7 E2 9,75 mm, D2 15,7±0,3 mm, F2 5,9 mm, G2 1,5 mm, H1 Ø20,8±0,3 mm, H2 Ø 20,3 mm, H3 20,8±0,3 mm.Example 3

[0034] In Fig. 8 is shown a cap ROPP 28 / 18 on container 14 using food-grade HDPE raw materials, and without necessitating additional finishing steps.

[0035] A4 Diameter: 31±0,5 mm.

[0036] B4 Height: 19,7±0,3 mm.

[0037] C4 Cap base height: 14,7 mm.

[0038] The side of the base / top of the cap has in total 144 toothing / ribs with the inner angles 69,06 and outer angles 2,5 %

[0039] The tethered ROPP 28 / 18 cap has 6 pieces of the nominal rupture bridge. The tether does not have any piece of the nominal rupture of the bridge design.

[0040] The cap tether has projected with the length around 15 mm and diameter are around 1,5 mm. Such design caps are produced with the Engel Victory VC330 / 50 Tech machine with the 8th cavities of special designed injection mold.Example 4

[0041] In Fig. 9 the tethered ROPP 28 / 36 cap 1b has 6 pieces of the nominal rupture bridge in rupture line 5b between cap base 2b and retaining ring 3b. The tether has one piece of the nominal rupture bridge 16 in the middle of the rupture line 5b.

[0042] The side of the base / top of the cap has in total 144 toothing / ribs with the inner angles 69,06° and outer angles 2,55 %.

[0043] The cap 1b tether rupture line 7b has a projected length of 32,2 mm and diameter 1,35 mm. And Fig 10 is shown example of ROPP 28 / 36 cap 1b on container 14 using food-grade HDPE raw materials, and without necessitating additional finishing steps. A5 Diameter: 31±0,5 mm.

[0044] B5 Height: 36±0,3 mm.

[0045] C5 cap base height: 14,7 mm.

[0046] The method wherein the specially designed mold plays a crucial role in defining the shape and characteristics of the tethered caps during the injection molding process. All this tethered caps are manufactured by using the injection molding process.List of reference signs:

[0047] 1. - a cap for the container; 1a. - a cap for the container; 1b. - a cap for the container; 1c. - a cap for the container; 2. - cap base; 2a. - cap base; 2b. - cap base; 3. - retaining ring; 3a. - retaining ring; 3b. - retaining ring; 4. - a tether; 4a - a tether; 4b - a tether; 5. - rupture bridge; 6. - breakable points; 7. - rupture line; 8. - rupture bridge; 9a. - space; 9b. - space; 10. - fixator; 11. - tongue; 12. - cylindrical wall; 13. - injection point; 13a. - injection point; 13b. - injection point; 14. - container (bottle); 15. - inner surface; 16. - solid unbreakable bridge.

Claims

1. A plastic cap (1) for a container comprising: a substantially cylindrical cap base (2) with a closed top and an open bottom; a retention ring (3) for tying the cap (1) on the container, connected to the bottom edge of the cylindrical cap base (2) via rupture bridge (5) line with breakable points (6); a fixator (10) extending downwards from a bottom edge of the cylindrical cap base (2); two tethers with tethering areas extending downwards from the bottom edge of the cylindrical cap base (2) on either sides of the fixator (10) and further connecting the cap base (2) to a retention ring (3), with at the bottom of both tethers located rupture line (7), tethers allowing the cap base (2) to be removed of the container while remaining attached to the retention ring (3); wherein when the cap body (2) is actuated to a fully open position: both tethers act as a torsion bar such that the fixator (10) may exert a force against a neck of the container for retaining the cylindrical cap base (2) in the fully open position, characterized in that said fixator (10) comprises a tongue (11) situated in the middle of the bottom part of the fixator (10), and the rupture line (7) is arranged under the tongue (11) according to the curvature of the tongue (11).

2. The plastic cap according to claim 1 characterized in that, tongue (11) positioned in the middle of the fixator's (10) bottom part, comprising from 1 / 2 to 1 / 3 of the fixator's (10) width.

3. The plastic cap according to any of claims 1, 2 characterized in that, length of the two tethers a first tether (4a) and a second tether (4b) may range from 10,5 to 20,5 mm, depending on cap diameter when the diameter is 40,3 mm optimal length of each tether 19,5 mm and with a wide of 1 to 2 mm, with optimal wide of 1,5 mm, and feature 6 rupture bridges (8) at a rupture line (7) located at the bottom of both the first tether (4a) and the second tether (4b).

4. The plastic cap (1), according to any of claims 1-3, characterized in that a first tethering area of the first tether (4a) and a second tethering area of the second tether (4b) extending downwards from the bottom edge of the cylindrical cap base (2) at a space (9a, 9b) from a fixator (10).

5. An injection molding process method for manufacturing tethered caps, comprising the steps of: a) heating food-grade High-Density Polyethylene (HDPE) material until it reaches a viscous melt state; b) injecting the hot HDPE melt into a closed mold, defining the shape of the tethered cap; c) allowing the injected HDPE material within the mold cavities to cool until it solidifies into a crystallized form; d) opening the mold and extracting the finished tethered cap; e) cooling the final product, created with a specially designed configuration, to room temperature.

6. The injection molding process method according to claim 5, wherein the step b) mold, defining the shape of the tethered cap according to any of claims 1-4.

7. The injection molding process method according to claim 6 wherein using a mold means for the mass production of tethered caps using food-grade HDPE raw materials, without necessitating additional finishing steps.

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