Processes for forming threads on thermoformed pet container closures

Abstract

A thermoforming process is provided for forming threads on an interior of thermoformed PET container closures. The thermoforming process includes heating a thermoplastic material to a temperature that allows the material to become more flexible and easier to shape. The material is placed into a mold configured to create desired features on the inside of the closure. After thermoforming, the closure is allowed to cool to room temperature in the mold to solidify the threads. The closure is removed from the mold without damaging the threads by rotating the mold portion forming the threads with a controlled rotation system. A timing mechanism is used to lift the closure at an axial rate timed with the rotation of the mold. A clearance mechanism is used to ensure a thread path follows the contour of the rotation as the closure is removed from the mold.

Description

PROCESSES FOR FORMING THREADS ON THERMOFORMEDPET CONTAINER CLOSURESCROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 642,600, filed May 3, 2024, German Patent Application No. 102024119672.6 filed July 10, 2024, U.S. Provisional Application No. 63 / 687,094, filed August 26, 2024, and U.S. Provisional Application No. 63 / 694,049, filed September 12, 2024, the disclosures of which are incorporated herein by reference in their entirety.FIELD

[0002] Embodiments of the present disclosure generally relate to container closures. More specifically, embodiments of the disclosure relate to processes for forming threads on thermoformed PET and HDPE container closures.BACKGROUND

[0003] The field of Plastics Forming, specifically Thermoforming, has seen significant advancements in recent years. Thermoforming involves heating a plastic sheet to a pliable forming temperature, stretching it over a mold, and then cooling it to a rigid state. The resulting product is a hollow shape that matches the contour of the mold. In the context of High-Density Polyethylene (HDPE) caps, this process is used to create consistent closures for applications. However, when it comes to Polyethylene Terephthalate (PET), the same process often results in damaged, inconsistent parts due to the material’s tendency to be brittle and crack or remain deformed under heat and pressure.

[0004] Various solutions have been proposed to avoid damaging the PET material during the thermoforming process. One approach is to form threads from the outside of the mold, although this results in less consistent threads compared to forming them from the inside. Another method is to use alternative processes such as injection molding or compression molding. However, these methods also have their own challenges, and none of them have been able to effectively remove the PET cap from the mold without causing damage.

[0005] Another problem with the conventional methods is that standard part removal by stripping from the mold fails when it comes to PET caps. This is because PET tends to crack or deform under the heat and pressure applied during the thermoforming process. Attempts to form the threads from the outside of the mold result in less consistent threads, while alternatives likeinjection molding and compression molding have their own challenges. Furthermore, the timing of lifting the closure when the thread forming component is moving is crucial to prevent deformation and unwanted height variation, which is difficult to achieve with the conventional methods.

[0006] Therefore, a need exists for methods or processes to effectively form consistent threads on thermoformed PET caps without damaging the cap during removal from the mold.SUMMARY

[0007] A thermoforming process and molds for use thereof are provided for forming threads on an interior of thermoformed PET container closures.

[0008] In some aspects, the techniques described herein relate to a process for forming threads inside a thermoformed PET container closure, including: heating a thermoplastic material in a thermoforming machine; thermoforming the thermoplastic material into a closure; cooling the closure in the thermoforming machine; removing the closure from a mold including the thermoforming machine by rotating the mold portion forming the threads; applying clearance to ensure smooth removal of the closure; and lifting the closure at an axial rate timed with the rotation of the thread component.

[0009] In some aspects, the techniques described herein relate to a process, wherein heating the thermoplastic material includes providing any of HDPE, PET, PHA, PLA or any type of polymer that is suitable for forming closures.

[0010] In some aspects, the techniques described herein relate to a process, wherein heating the thermoplastic material includes heating the thermoplastic material to a temperature that allows the thermoplastic material to become more flexible and easier to shape.

[0011] In some aspects, the techniques described herein relate to a process, wherein heating the thermoplastic material includes heating the thermoplastic material to a temperature ranging between about 80°C and about 120°C.

[0012] In some aspects, the techniques described herein relate to a process, wherein thermoforming includes injection molding or compression molding a HDPE or PET material.

[0013] In some aspects, the techniques described herein relate to a process, wherein thermoforming the thermoplastic material includes configuring the mold to create desired features on the inside of the closure.

[0014] In some aspects, the techniques described herein relate to a process, wherein thermoforming the thermoplastic material includes configuring the mold to accommodate the formation of threads on the inside of the closure.

[0015] In some aspects, the techniques described herein relate to a process, wherein thermoforming the thermoplastic material includes applying pressure to the thermoplastic material using the thermoforming machine.

[0016] In some aspects, the techniques described herein relate to a process, wherein thermoforming the thermoplastic material includes applying a pressure that is sufficient to shape the thermoplastic material into the closure but not so high as to cause damage to the PET material.

[0017] In some aspects, the techniques described herein relate to a process, wherein cooling the closure includes allowing the closure to cool to room temperature in the thermoforming machine.

[0018] In some aspects, the techniques described herein relate to a process, wherein cooling the closure includes providing water cooling channels in the mold to cool the closure.

[0019] In some aspects, the techniques described herein relate to a process, wherein providing water cooling channels includes forming a 3D network of cooling channels to reduce the pitch between individual forming portions of the mold.

[0020] In some aspects, the techniques described herein relate to a process, wherein removing the closure includes using a controlled rotation system to ensure consistent and accurate rotation of the threads.

[0021] In some aspects, the techniques described herein relate to a process, wherein using the controlled rotation system includes using any one or more of a servo, a belt, a chain drive system, or any combination thereof.

[0022] In some aspects, the techniques described herein relate to a process, wherein using the controlled rotation system includes operating the controlled rotation system at a speed ranging between about 10 RPM and about 20 RPM.

[0023] In some aspects, the techniques described herein relate to a process, wherein applying clearance includes using a clearance mechanism to ensure a thread path follows the contour of the rotation as the closure is removed from the mold.

[0024] In some aspects, the techniques described herein relate to a process, wherein using the clearance mechanism includes providing clearance along the threads to enable smooth removal of the closure from the mold.

[0025] In some aspects, the techniques described herein relate to a process, wherein using the clearance mechanism includes allowing for vents or other interruptions in the closure.

[0026] In some aspects, the techniques described herein relate to a process, wherein lifting the closure includes using a timing mechanism to lift the closure at an axial rate that prevents deformation and unwanted height variation of the closure.

[0027] In some aspects, the techniques described herein relate to a process, wherein using the timing mechanism includes lifting the closure at an axial rate of 1-2 mm / s. (a) (b) (c) (d) (e) (f)

[0028] In some aspects, provided herein is a process for thermoforming a closure for a container, including: (a) providing a heated thermoplastic material and a mold, wherein the mold includes: (i) a first portion configured to form a plug seal of the closure, wherein the plug seal seats against an inner surface of the container; (ii) a second portion configured to form an annular wall of the closure, wherein the annular wall seats against a top surface of a rim of the container; and (iii) a threaded portion configured to form an outer cylindrical wall of the closure that includes threads, wherein the outer cylindrical wall extends downward from the annular wall, and wherein the threads of the outer cylindrical wall engage with external threads of the container; (b) thermoforming the heated thermoplastic material into a closure by placing the heated thermoplastic material into the mold; (c) removing the closure from the mold by: (i) rotating at least the threaded portion of the mold, and (ii) lifting the closure at an axial rate timed with the rotating.

[0029] In some aspects, provided herein is a process, wherein the mold further includes a knurled portion configured to form a plurality of knurls onto an exterior of the closure.

[0030] In some aspects, provided herein is a process, further including adjusting a size and / or a shape of each of the plurality of knurls.

[0031] In some aspects, provided herein is a process, further including forming cams on the closure prior to removing the closure from the mold.

[0032] In some aspects, provided herein is a process, wherein the cams are formed using a cam-forming tool while the thermoplastic material is warm and pliable.

[0033] In some aspects, provided herein is a process, wherein the cams are formed using the cam-forming tool after the thermoplastic material has cooled to room temperature.

[0034] In some aspects, provided herein is a process, wherein the cams are formed in steps at angles ranging between about -10 degrees and about 190 degrees.

[0035] In some aspects, provided herein is a process, wherein the cams are formed by folding 90-degree tabs in steps including about 30 degrees, about 60 degrees, about 90 degrees, or about 140 degrees, then inverting the tabs with a plunger, wherein the tabs are pre-trimmed at an edge of the closure.

[0036] In some aspects, provided herein is a process, wherein the 90-degree tabs are folded along a circumference of the closure using a ramp.

[0037] In some aspects, provided herein is a process, wherein the 90-degree tabs are folded by pushing the closure through a tube, thereby folding the 90-degree tabs into a vertical position.

[0038] In some aspects, provided herein is a process, wherein the tube is cylindrically or conically shaped.

[0039] In some aspects, provided herein is a process, wherein the threaded portion of the mold is shaped to form undercuts in the threads.

[0040] In some aspects, provided herein is a process, wherein the undercuts are formed with a depth ranging from 0.1 mm to 1 mm.

[0041] In some aspects, provided herein is a process, wherein the undercuts are formed at an angle ranging from -10 degrees to 190 degrees, with respect to a base of the mold.

[0042] In some aspects, provided herein is a process, further including slitting the closure to form a tamper evidence band.

[0043] In some aspects, provided herein is a process, wherein the thermoplastic material is selected from the group consisting of: HDPE, PET, PHA, PLA, or any combination thereof.

[0044] In some aspects, provided herein is a process, wherein the thermoforming of the thermoplastic material includes applying pressure to the thermoplastic material using a thermoforming machine.

[0045] In some aspects, provided herein is a process, wherein the pressure is sufficient to shape the thermoplastic material into the closure without causing damage to the thermoplastic material.

[0046] In some aspects, provided herein is a process, wherein the pressure is from about 4 bar to about 10 bar to the thermoplastic material.

[0047] In some aspects, provided herein is a process, wherein the heated thermoplastic material is heated to a temperature ranging from about 80 °C and about 120 °C prior to the thermoforming.

[0048] In some aspects, provided herein is a process, further including cooling the closure prior to removing from the mold.

[0049] In some aspects, provided herein is a process, wherein the cooling includes allowing the closure to cool to room temperature.

[0050] In some aspects, provided herein is a process, wherein the cooling is performed using water cooling channels in the mold to cool the closure.

[0051] In some aspects, provided herein is a process, wherein the water cooling channels are arranged in a 3D network of cooling channels to reduce a pitch between individual forming portions of the mold.

[0052] In some aspects, provided herein is a process, wherein the rotating of at least the threaded portion of the mold is performed using a controlled rotation system.

[0053] In some aspects, provided herein is a process, wherein the controlled rotation system includes a servo, a belt, a chain drive system, or a combination thereof.

[0054] In some aspects, provided herein is a process, wherein the controlled rotation system rotates the threaded portion of the mold at a speed ranging from about 10 RPM and about 20 RPM.

[0055] In some aspects, provided herein is a process, wherein the removing of the closure from the mold further includes applying clearance to ensure smooth removal of the closure.

[0056] In some aspects, provided herein is a process, wherein the clearance is applied using a clearance mechanism to ensure a thread path follows a contour of the rotating as the closure is removed from the mold.

[0057] In some aspects, provided herein is a process, wherein the clearance mechanism allows for vents in the closure.

[0058] In some aspects, provided herein is a process, wherein using the axial rate includes 1- 2 mm / s.

[0059] In some aspects, provided herein is a mold for thermoforming a closure for a container, including: (a) a first portion configured to form a plug seal of the closure, wherein the plug seal seats against an inner surface of the container; (b) a second portion configured to form an annular wall of the closure, wherein the annular wall seats against a top surface of a rim of the container; and (c) a threaded portion configured to form an outer cylindrical wall of the closure that includes threads, wherein the outer cylindrical wall extends downward from the annular wall, and wherein the threads of the outer cylindrical wall engage with external threads of the container.

[0060] Also disclosed herein is a system that comprises: (a) a mold as described herein, (b) thermoplastic material; and (c) a controlled rotation system that comprises a servo, a belt, a chain drive system, or a combination thereof. In some embodiments, the system further comprises a thermoforming machine. In some embodiments, the thermoforming machine comprises a rotary thermoforming machine. In some embodiments, the rotary thermoforming machine rotates at a speed ranging from about 1 RPM to about 80 RPM.

[0061] These and other features of the concepts provided herein may be better understood with reference to the drawings, description, and appended claims.BRIEF DESCRIPTION OF THE DRAWINGS

[0062] The drawings refer to embodiments of the present disclosure in which:

[0063] Figures 1A-1B illustrate perspective and cross-sectional views, respectively, of an exemplary embodiment of a thermoforming mold including a thread about a circumference of the mold, according to the present disclosure;

[0064] Figures 2A-2B illustrate side views of an exemplary embodiment of a thermoforming mold including a thread about a circumference of the thermoforming mold, in accordance with the present disclosure;

[0065] Figures 3A-3B illustrate perspective and cross-sectional views, respectively, of an exemplary embodiment of a thermoformed PET container closure thermoformed by a thermoforming mold, including folding tabs arranged around a circumference of a tamper evidence feature, according to the present disclosure; and

[0066] Figure 4 illustrates a perspective view of an exemplary embodiment of a thermoformed PET container closure including a thread about a circumference of the closure, according to the present disclosure;

[0067] Figure 5 illustrates a side view of an exemplary embodiment of a thermoformed PET container closure including a thread about a circumference of the closure, in accordance with the present disclosure;

[0068] Figure 6 illustrates a top view of an exemplary embodiment of a thermoformed PET container closure including a thread about a circumference of the closure, according to the present disclosure; and

[0069] Figure 7 illustrates an exemplary embodiment of a thermoforming process whereby consistent threads can be formed on a thermoformed PET container closure by a thermoforming mold, in accordance with the present disclosure.

[0070] Figures 8A-8E illustrate a schematic representation of the sequence of the manufacturing method according to this disclosure using a device, in accordance with the present disclosure;

[0071] Figure 9 illustrates a perspective view of an assembly with a rotatable mold segment and a rotationally fixed mold segment of a device, in accordance with the present disclosure;

[0072] Figure 10 illustrates a sectional view of the assembly according to FIG. 9.

[0073] Figure 11 illustrates a perspective view of a screw cap produced using the method, in accordance with the present disclosure; and

[0074] Figure 12 illustrates a representation of the drive units for the rotatable mold segments of a device in plan view, in accordance with the present disclosure.

[0075] While the present disclosure is subject to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and will herein be described in detail. The present disclosure should be understood to not be limited to theparticular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure.DETAILED DESCRIPTION

[0076] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure. It will be apparent, however, to one of ordinary skill in the art that the processes disclosed herein may be practiced without these specific details. In other instances, specific numeric references such as “first container,” may be made. However, the specific numeric reference should not be interpreted as a literal sequential order but rather interpreted that the “first container” is different than a “second container.” Thus, the specific details set forth are merely exemplary. The specific details may be varied from and still be contemplated to be within the spirit and scope of the present disclosure. The term “coupled” is defined as meaning connected either directly to the component or indirectly to the component through another component. Further, as used herein, the terms “about,” “approximately,” or “substantially” for any numerical values or ranges indicate a suitable dimensional tolerance that allows the part or collection of components to function for its intended purpose as described herein.

[0077] In general, there is a need for processes for effectively forming consistent threads on thermoformed PET caps without damaging the caps during removal from the mold. Embodiments provided in the present disclosure provide processes for forming threads on thermoformed PET container closures. The processes disclosed herein solve technical problems encountered with conventional methods, such as 1) the inability to effectively remove PET caps from the mold without causing damage, 2) the inconsistency of threads when formed from the outside of the mold, and 3) the difficulty in timing the lifting of the closure when the thread forming component is moving to prevent deformation and unwanted height variation.

[0078] FIGS. 1A-1B illustrate perspective and cross-sectional views, respectively, of an exemplary embodiment of a mold 100 for use in thermoforming closure from a sheet made from a thermoforming material. The mold 100 is particularly well suited for including one or more threads formed by way of the thermoforming processes described herein. In general, the mold is designed with precision to create the desired features on the inside of the closure, including the threads and other internal components. Upon thermoforming of the closure, the mold 100 rotates to unthread from the molded part.

[0079] In some embodiments, as shown in FIGS. 1A-1B, the mold 100 comprises at least a primary portion 101. In some embodiments, the mold 100 comprises a stack of portions, including at least a secondary portion 102 that does not rotate but rather demolds vertically. In some embodiments, the secondary portion 102 can be removed from the primary portion 101 by applying torque to the secondary portion 102. In some embodiments, the secondary portion 102 can be slipped out from the primary portion 101. In some embodiments, the mold 100 is monolithic. In some embodiments, the mold comprises one or more vents 103. The vents 103 allow air that would otherwise be trapped to escape from underneath the sheet that is forming on the mold 100, thereby improving formation of the sheet to the mold 100.

[0080] In some embodiments, the mold 100 is configured to operate at a pressure ranging between about 4 bar to about 10 bar and a temperature range between about 80°C and about 120°C. In some embodiments, the mold is made of aluminum, steel, stainless steel, brass, copper, bronze, or various grades, alloys, a tool steel, or combinations thereof. In some embodiments, the aluminum comprises Aluminum T-300, Aluminum 6061-T6, Aluminum 2024-T4, Aluminum 7075-T6, or the like or a combination thereof. In some embodiments, the steel comprises P20 / 30 / 40, H-13, 4140 prehard steel, or the like. In some embodiments, the stainless steel comprises 420 Stainless Steel, Stainless Steel 400 series, HH Stainless Steel or the like. In some embodiments, the copper comprises C-18, high copper alloys 83, 940, 88, 972, 95 or the like. In some embodiments, the bronze comprises SAE660 or the like. In some embodiments, the mold is made of Aluminum Bronze Alloys 18, 25, 21, 45 or the like. In some embodiments, the tool steel comprises O-l, A-2, A-6, A-8, D-2, D-3, S-7, W-l series, DC-53, Vanadis 4 / 6 / 10, Ml, M2, M3, T-3, T-16, or the like. In some embodiments, the mold comprises a coating for improving resistance to wear or corrosion. In some embodiments, the coating comprises anodized aluminum, PTFE-anodized aluminum, electroless nickel plating, ferrous metals (e.g., NiB, TiN, Ni-PTFE, diamond chrome plating), or the like.

[0081] In some embodiments, as shown in FIGS. 1A-1B, the mold 100 comprises at least a first portion configured to form a plug seal of the resulting closure, such that the plug seal seats against an inner surface of the container. In some embodiments, the first portion comprises a cover wall 104, an annular wall 120 and a cylindrical wall 124 that extends downwardly from the annular wall 120 and surrounds the cover wall 104.

[0082] In some embodiments, as shown in FIGS. 1A-1B, the mold 100 comprises a second portion configured to form an annular wall of the resulting closure, such that the annular wall seats against a top surface of a rim of the container. The second portion may include a side wall 108.The side wall 108 is integrally connected to the cover wall 104 and oriented transversely to the cover wall 104. The side wall 108 may be circumferentially closed.

[0083] In some embodiments, as shown in FIGS. 1A-1B, the mold 100 comprises a threaded portion configured to form an outer cylindrical wall of the closure that comprises threads, wherein the outer cylindrical wall extends downward from the annular wall, and wherein the threads of the outer cylindrical wall engage with external threads of the container. In some embodiments, the threaded portion includes one or more external threads 128 formed into the side wall 108 for forming internal threads in the closure. In some embodiments, the external threads 128 are confined to the primary portion 101. The resulting internal threads are configured to engage with external threads of the finish portion of the container to be closed with the closure. The threads 128 may be continuous threads or may be interrupted threads. In the illustrated embodiment, the mold 100 includes one thread 128, with one thread start 132 at the beginning of the thread 128. In some embodiments, however, the mold 100 may include a plurality of threads 128, such as, for example, three threads distributed uniformly around the side wall 108 of mold 100. As such, each of the plurality of threads 128 includes one of a corresponding plurality of thread starts 132.

[0084] In some embodiments, the threaded portion of the mold is shaped to form undercuts in the threads. In some embodiments, the undercuts are formed with a depth ranging from 0.1 mm to 1 mm. In some embodiments, the undercuts are formed at an angle ranging from a slight draft of a few minutes to -30 degrees. With -10 degrees being relatively easy to release. Alternatively hinges can be molded with even a positive 190 degree angle, with respect to a base of the mold, which also requires an undercut that must be released.

[0085] In some embodiments, as shown in FIGS. 1A-1B, the mold 100 further includes a knurled portion configured to form a plurality of knurls onto an exterior of the closure. In some embodiments, the knurled portion includes a plurality of knurls 148 distributed around the circumference of the mold 100. In some embodiments, a size and / or a shape of each of the plurality of knurls may be adjusted as needed. In some embodiments, the external knurls 148 are confined to the secondary portion 102. In some embodiments, the mold 100 may further include a tamper evidence feature 140 distributed around the circumference of the mold 100. In some embodiments, tamper evidence feature 140 is confined to the secondary portion 102.

[0086] In some embodiments, a plurality of external knurls (not shown) are distributed around the circumference of the external threads 128. The external knurls may serve in particular to improve the grip of the external threads 128 of the resulting closure.

[0087] In some embodiments, the external threads 128 may form partial threads (not shown). In some embodiments, the partial threads can be removed if the thread is interrupted. A partial twist may be an option to slip the closure out through gaps (i.e., vents) between the threads.

[0088] In some embodiments, the mold 100 comprises a female mold (not shown). Such a female mold would comprise inverting the mold such that the thermoforming material would be inserted into the female mold to impart features from the female mold, rather than the thermoforming material being placed onto the mold to impart features from the mold 100.

[0089] FIGS. 2A-2B illustrate side views of the mold 100. As shown in FIGS. 2A-2B, the mold 100 has a vertical axis 116. The side wall 108 extends along this vertical axis 116. The vertical axis 116 is transverse and in particular perpendicular to the cover wall 104. In some embodiments, the vertical axis 116 comprises an axis of rotational symmetry of the mold 100. FIG. 2B further illustrates arrows for indicating controlled rotation of the mold 100 and lifting of the mold along vertical axis 116. The controlled rotation allows for precise timing of lifting the thermoformed closure away from the mold 100 when the thread forming component is rotating. In some embodiments, the controlled rotation is performed by applying a torque to the mold 100. In some embodiments, torque on the closure may be distributed throughout the closure. In some embodiments, the closure may be held in place by a clamp on the sheet. In some embodiments, closure may be held in place by neighboring cavities. In some embodiments, applying torque can push the secondary portion 102 of the mold stack out of the sheet. In some embodiments, the secondary portion 102 can be pulled out independently.

[0090] FIGS. 3A-3B illustrate an exemplary embodiment of a closure 200 thermoformed by the mold 100. Features of the mold 100 are imparted to the closure 200, discussed in more detail below with respect to FIGS. 4-6. In general, the closure 200 may be a monolithic portion of thermoplastic material and produced by thermoforming with the mold 100. The thermoplastic material may comprise a polystyrene such as SAN or ABS, or a polyolefin such as PP or PE, or a polycarbonate or, in particular, a polyester such as PET, PBT or PEF. Further, in some embodiments, the closure 200 can be made from a single thermoplastic material or can be made from a plurality of thermoplastic materials. In one embodiment, the material of the closure 200 comprises PET, and the container, which is to be closed with the closure 200, is also made of PET. The thermoformed closure 200 further has an interior (not illustrated) configured to receive a finish portion of the container to be closed with the closure 200. Further details regarding techniques for forming the closure 200 may be found in PCT Application, entitled “Polyester Resin Closures ForContainers,” filed on April 20, 2023, and having application serial number PCT / US23 / 66008, the entirety of said application being incorporated herein by reference.

[0091] In some embodiments, as shown in FIGS. 3A-3B, folding tabs 300 (i.e., “flaps”) are arranged around the circumference of the tamper evidence feature 240. The folding tabs 300 form a tamper-evident device on the closure 200; when a corresponding closure 200 closes a container, increased effort and in particular increased force must be exerted at least when the container is first opened due to the presence of the folding tabs 300. The folding tabs 300 are integrally connected to a tamper evidence feature 240, which has been imparted to the closure 200 by the tamper evidence feature 140 of the mold 100. The folding tabs 300 may be manufactured as “prefold tabs” integrally with the closure 200. In a pre-fold state, the folding tabs 300 are arranged in an outward ring that surrounds the tamper evidence feature 240 and an opening of the closure 200. The folding tabs 300 are arranged and formed in such a way that they can be folded into the opening and positioned in the interior of the closure 200.

[0092] In some embodiments, each of the folding tabs 300 are shaped to include a two- dimensional (2D) geometry, three-dimensional (3D) geometry, or a combination thereof. In some embodiments, the geometry may comprise an associated height increment along any number of portions of the geometry. In some embodiments, not all of the folding tabs 300 have the same geometry. In some embodiments, each of the folding tabs 300 are of a different geometry or shape from others of the folding tabs 300.

[0093] FIGS. 4-6 illustrate perspective, side, and top views, respectively, of an exemplary embodiment of a thermoformed PET container closure 200 that is particularly well suited for including one or more threads formed by way of the thermoforming processes described herein.

[0094] As shown in FIGS. 4-6, the closure 200 has a cover wall 204 and a side wall 208. The side wall 208 is integrally connected to the cover wall 204 and oriented transversely to the cover wall 204. The side wall 208 is circumferentially closed. The closure 200 has an interior (not illustrated) configured to receive a finish portion of the container to be closed with the closure 200. The interior is partially bounded by the cover wall 204 and the side wall 208. The closure 200 includes an opening 212 (see FIG. 5) opposite to the cover wall 204, through which “access” to the interior is possible.

[0095] In some embodiments, shown in FIGS. 4-6, the closure 200 includes an annular wall 220 and a cylindrical wall 224 that extends downwardly from the annular wall 220 and surrounds the cover wall 204. Interior surfaces of the annular wall 220 and the cylindrical wall 224 comprisea plug seal (not shown) for scaling against an inner surface of a finish portion of the container to be closed with the closure 200. An interior surface of the annular wall 220 may be configured to scale against a top surface of a rim of the finish, while an outwardly facing radial surface of the cylindrical wall 224 may be dimensioned for an interference fit with a corresponding inwardly facing surface of rim of finish for scaling. As the closure 200 is threaded onto the finish, the plug seal is forced into a mouth of the finish and into a compressed state in which the outwardly facing radial surface of the cylindrical wall 224 pushes against the inwardly facing surface of finish, thereby forming a seal.

[0096] As shown in FIG. 5, the closure 200 has a vertical axis 216. The side wall 208 extends along this vertical axis 216. The vertical axis 216 is transverse and in particular perpendicular to the cover wall 204. The opening 212 is also oriented transversely and in particular perpendicular to the vertical axis 216. In some embodiments, the vertical axis 216 comprises an axis of rotational symmetry of the closure 200. In some embodiments, wherein the closure 200 serves as a closure cap for a bottle, the closure 200 is at least approximately cylindrical with the side wall 208 disposed symmetrically around the vertical axis 216.

[0097] As shown in FIGS. 4-5, the closure 200 includes a plurality of external knurls 244 distributed around the circumference of the threaded portion 236. The external knurls 244 serve in particular to improve the grip of the threaded portion 236 of the closure 200. Further, the closure 200 includes a plurality of knurls 248 distributed around the circumference of the tamper evidence feature 240. In some embodiments, the plurality of knurls 248 are distributed along an upper circumference or a lower circumference of the closure 200, or therebetween.

[0098] In some embodiments, shown in FIGS. 4-6, the closure 200 includes one or more internal threads 228 formed into the side wall 208 for engaging with external threads of the finish portion of the container to be closed with the closure 200. The threads 228 may be continuous threads or may be interrupted threads. In the illustrated embodiment, the closure 200 includes one thread 228, with one thread start 232 at the beginning of the thread 228. In some embodiments, however, the closure 200 may include a plurality of threads 228, such as, for example, three threads distributed uniformly around the side wall 208 of closure 200. As such, each of the plurality of threads 228 includes one of a corresponding plurality of thread starts 232.

[0099] With continuing reference to FIGS. 4-6, the closure 200 may be viewed as broadly comprising a threaded portion 236 and a tamper evidence feature 240. As the closure 200 isthreaded onto a finish portion of a container, the tamper evidence feature 240 rides over a ledge of the finish portion, clears the ledge, and fits into place beneath ledge.

[0100] As shown in FIGS. 4-6, the closure 200 includes a plurality of external knurls 244 distributed around the circumference of the threaded portion 236. The external knurls 244 serve in particular to improve the grip of the threaded portion 236 of the closure 200. Further, the closure 200 includes a plurality of knurls 248 distributed around the circumference of the tamper evidence feature 240.

[0101] In some embodiments, the closure 200 includes a plurality of knurls (not shown) about the circumference of an inner surface of a tamper evidence feature 240. The plurality of internal knurls may be distributed evenly or unevenly about the circumference of the inner surface of tamper evidence feature 240.

[0102] In some embodiments, the tamper evidence feature 240 may include a plurality of spaced-apart bridges (not shown) that connect the tamper evidence feature 240 to the threaded portion 236 of the closure 200. In the event that the closure 200 is unthreaded from the finish portion, tamper evidence feature 240 will be retained in position by the ledge of the finish portion. The upward force from unthreading of the closure 200 will eventually cause sufficient stress on the bridges that they will break, providing evidence that the closure 200 has been tampered with.

[0103] FIG. 7 illustrates an exemplary embodiment of a thermoforming process 400 whereby consistent threads can be formed on a thermoformed PET container closure, such as the closure 200 shown in FIGS. 3-6, without causing damage, as described herein. The process 400 begins at step 410, wherein a thermoplastic material, such as HDPE or PET, is heated in an industrial oven to a temperature that allows the material to become more flexible and easier to shape. In some embodiments, ceramic heating elements are used to heat the material. For injection molding, the closure can be formed from a molten state with a polymer delivered via a hot runner. In some embodiments, the temperature ranges between about 80°C and about 120°C. This temperature range has been found for both HDPE and PET materials, allowing for effective thermoforming while minimizing the risk of degradation.

[0104] In step 420, the heated HDPE or PET material is placed into a mold. In some embodiments, the heated HDPE or PET material is placed into a thermoforming machine comprising the mold. It is contemplated that in some embodiments, the heated HDPE or PET material may, alternatively, be injection molded or compression molded. The mold is designed with precision to create the desired features on the inside of the closure, including the threads andother internal components. The thermoforming mold is configured to operate at a pressure ranging between about 4 bar to about 10 bar and a temperature range between about 80°C and about 120°C. Experimental observations have demonstrated that these conditions are optimal for forming threads in container closures. Experimental observations have also demonstrated that this pressure is sufficient to shape the PET material into the desired closure design but not so high as to cause damage to the PET material. Cams may be formed on the flaps during this step or the flaps themselves can be left to form cams in later steps.

[0105] In some embodiments, the thermoforming machine comprises a rotary thermoforming machine. Rotary thermoforming machines may serve as an alternative to thermoforming closures in a previously formed sheet that is subsequently heated, such that parts can be formed from a thermoplastic material out of the molten state, As a result, the parts may be extruded like a sheet that is quenched onto a chilled mold. Rather than forming only a sheet, the chilled mold, typically in the form of a roller or wheel, may also include any number of intricate parts (e.g., threads) for forming closures as segments on the roller. This works particularly well for positive molded parts, also known generally as male mold components. Similar to forming on a flat mold, individual closures with threads may be rotationally removed from a sheet after it is cooled. Such removal may be driven by rotation of a cam or gear within a roller. This method may allow for high fidelity formation of the part and any engravings on the part. In some embodiments, the thermoforming machine comprises multiple rotary thermoforming machines in series

[0106] In some embodiments, a diameter of a roller or wheel may is matched to an extrusion rate and the part thickness. For example, as a thickness of an extruded sheet decreases (e.g., from 1 mm to 0.5 mm), the parts may need to be removed by rotating off at a faster rate to accommodate the larger material. In some embodiments, the removal may be timed with a cooling rate of the thermoplastic material and a rotational step of the parts. In some embodiments, the formation of knurls on the formed parts may be performed with another roller mated and timed to coin knurls on outer portions of the parts. If not trimmed in place, trimming of the parts from the sheet can be performed in a second station. In some embodiments, design of the mold, roller, and part may allow room for cooling the roller, which, for example, may be performed using chilled water. With advances in additive manufacturing of steels or other alloys, some mold components can be generated by additive manufacturing to get around standard machining limitations that otherwise may cause excessive skeleton scrap.

[0107] In some embodiments, a rotary thermoforming machine comprises a hinged wheel or roller for receiving an extrusion die or sheet, a screen changer / vacuum pump, and a press. In someembodiments, the rotary thermoforming machine comprises a rotary mold system. In some embodiments, the rotary thermoforming machine rotates at a desired speed, such as, for example, a speed less than 1 RPM or greater than 80 RPM, or a speed ranging from about 1 to about 80 RPM, such as from about 1 to about 5 RPM, from about 5 to about 10 RPM, from about 10 to about 20 RPM, from about 20 to about 30 RPM, from about 30 to about 40 RPM, from about 40 to about 50 RPM, from about 50 to about 60 RPM, from about 60 to about 70 RPM, or from about 70 to about 80 RPM.

[0108] After the thermoforming process is complete, the process 400 advances to step 430, wherein the molded closure is cooled to room temperature. In some embodiments, the cooling takes place in the thermoforming machine. This cooling step helps to set the shape of the closure and solidify the threads. In some embodiments, water cooling channels are provided in the mold to cool the closure. In order to reduce the pitch or distance between individual forming portions of the mold, a 3D network of cooling channels is beneficial. These can be machined by brazing mold parts together after milling the cooling channels or through additive manufacturing instead of typical gun drilling methods that are used to form conventional cooling channels.

[0109] In some embodiments, while the closure is allowed to cool or after the closure has cooled, the closure is then trimmed from the thermoformed web in a pre-folded state. The trimming of the closure from the thermoformed web is configured in a way that allows for the formation of cams at various angles, overcoming the limitations of traditional methods. Ideally while the PET material is warm and pliable, but optionally after cooling to room temperature, cams can be formed on the closure using a cam-forming tool. The cams can be formed in steps at angles ranging between about -10 degrees and about 190 degrees, with an emphasis on starting with 90- degree flaps. This configuration maximizes the distance between the skirt of the closure to the trimming surface, providing clearance and eliminating a need for the closure to stretch when being removed from the mold.

[0110] In the case of 90-degree flaps, however, the centering of a trimming tool can limit the accuracy of the formed cams. Too much trimming offset can lead to cams that are short or long and then reduce the consistent effectiveness of tamper evidence. This is sufficient to form functional tamper evidence. However, expanding the precision limitation opens up the option to increase the number of cavities in the mold. This can be enabled by thermoforming cams directly on the tab before folding and allow the flat part of the tab that remains for trimming to extend past the tamper evidence bead upon application of the closure to a finish portion of a container.[oni] In all cases, folding of the tabs may be done sequentially. In some embodiments comprising 90-degree tabs, the tabs can be folded in steps, such as 30 degrees, 60 degrees, 90 degrees, 140 degrees and then finally invert the tabs with a plunger. Folding can be done along the circumference using a ramp or all at once through a cylinder or a conically shaped tube. Keeping the closure aligned with the folding tool is important and can be done with an internal drive that drives the closure along the folding ramp engaging with optional knurls formed in the band. In some embodiments, the tabs are pre-trimmed at an edge of the closure.

[0112] Pushing the closure with flaps through a cylinder or a conically shaped tube to encourages the flaps to fold into a vertical position. This creates a cap that is shaped in a more usual fashion that can then be presented to typical closure folding equipment for further processing. Experimental observations have demonstrated that moving from a multi-step folding process, as described above, to a continuous folding process provides an all-at-once folding step that benefits the cycle time of the process.

[0113] In some embodiments, a slitting process can be applied to form a tamper evidence band on the closure. This process ensures that the closure remains intact until it is opened on a container for the first time, providing a clear indication of potential tampering. This embodiment provides a feasible process for producing PET closures with tamper evidence using thermoforming techniques and specific cam designs. The use of outer facing portions eliminates the need for the closure to stretch when being removed from the mold, a process that is not possible with cooled PET parts.

[0114] After the cooling, trimming, and / or slitting processes, in step 440, the closure is removed from the mold by using a controlled rotation system. In some embodiments, the controlled rotation system comprises a servo, a belt, or a chain drive system that is configured to ensure consistent and accurate rotation of the threads. In some embodiments, the controlled rotation system operates at a speed ranging between about 10 RPM and about 20 RPM, which allows for removing closures without causing damage.

[0115] In some embodiments, a clearance mechanism is used as the closure is removed from the mold, as described in connection with step 440. The clearance mechanism is configured to ensure the thread path follows the contour of the rotation while the closure is being removed. Along the threads, a clearance may be provided to allow for smooth removal of the closure from the mold. This clearance could allow for vents or other interruptions, which may be provided through a vertically moving part that slips from the closure after formation before step 440. Thisclearance allows for smooth removal of the closure from the mold and prevents damage to the threads.

[0116] In step 450, a timing mechanism is used to lift the closure at an axial rate that is correctly timed with the rotation of the thread component. Timing of lifting the closure when the thread forming component is moving is critical to prevent deformation and unwanted height variation. In some embodiments, the closure is removed at an axial rate of 1-2 mm / s, which has been found to be optimal for preventing deformation and unwanted height variation.

[0117] It should be understood that the controlled rotation system, the clearance mechanism, and the timing mechanism, described in steps 176-450, cooperate to prevent damage to the closure during removal from the mold. As such, the process 400 advantageously allows for removing HDPE, PET, PHA, PLA or any type or combination of polymer closures from molds without causing damage.

[0118] Compared with conventional methods, the beneficial effects of the thermoforming process 400 provided herein are as follows:

[0119] 1. Improved Consistency: The thermoforming process 400 provided herein ensures a higher level of consistency in the quality of the threads by enabling the formation of threads from the inside of the closure. This is a significant improvement over the conventional methods of forming the threads from the outside, which results in less consistent threads.

[0120] 2. Reduced Damage: The thermoforming process 400 provided herein enables removing PET closures from the mold without causing damage. This is a major breakthrough in the field of Plastics Forming, particularly by employing Thermoforming, where previous attempts using injection or compression molding have resulted in damaged or inconsistent parts due to the tendency of the material to crack or deform under heat and pressure.

[0121] 3. Enhanced Control: The thermoforming process 400 disclosed herein introduces a controlled rotation technology that allows for precise timing of lifting the closure when the thread forming component is rotating. This not only prevents deformation of the closure but also minimizes unwanted height variation. This level of control is not achievable with the conventional processes.

[0122] 4. Versatility: The thermoforming process 400 is not limited to a specific type of mold or plastic material. The process 400 can be applied to any mold and any plastic material that is suitable for thermoforming. Similarly, it is contemplated that the process 400 can be applied toinjection or compression molding for ejecting PET closures. This makes the thermoforming process 400 a versatile solution that can be used in a wide range of applications, without limitation.

[0123] 5. Efficiency: The thermoforming process 400 includes the use of a servo, belt, or chain drive system to rotate the threads as the closure is lifted from the mold. This not only speeds up the process but also reduces the risk of human error, making it a more efficient solution than the conventional methods.

[0124] It is contemplated, therefore, that the thermoforming process of the present disclosure provides a practical and efficient solution to the technical problem of threads on the inside of thermoformed PET closures or thermoformed caps from any polymer, offering significant improvements over existing approaches in terms of efficiency, quality control, versatility, enhanced user experience, and cost-effectiveness.

[0125] Moreover, as mentioned hereinabove, selecting PET is logical for this process in order to make mono-material recyclable containers. However, PHA or PLA are also practical options to enable the manufacture of bio-degradable closures. Further, HDPE or PP can be adapted to the process and allow the use of a wider spectrum of melt flow indices, which would be important for the use of recycled resins.Production of screw caps by thermoforming

[0126] Further disclosed herein is a method and a device for producing screw caps by thermoforming. In some embodiments, the procedure includes the following steps:

[0127] Providing a film made of a thermoplastic material and heating the film;

[0128] feeding the film between a lower tool and an upper tool, which are movable relative to one another in an axial direction perpendicular to the film, wherein the lower tool comprises a plurality of rotatable mold segments, the molding surfaces of which have an external thread complementary to the internal thread of the closure body or an internal thread complementary to the external thread of the closure body;

[0129] Closing the lower tool and the upper tool while the film is subjected to a differential pressure in order to deform the film and form the closure bodies on the molding surface of the rotatable mold segments;

[0130] Allow the foil to cool;

[0131] at least partially opening the lower tool and the upper tool while the rotatable mold segments perform a rotation around the axial direction synchronized according to the pitch of the internal thread in order to remove the closure bodies from the mold segments;

[0132] Removing the film with the formed closure bodies from the lower tool and upper tool; and

[0133] Separating the individual closure bodies from the foil to obtain the screw caps.

[0134] Further disclosed herein is a method for producing screw caps by means of thermoforming, wherein the screw caps each comprise a closure body with a cover wall and a side wall which define an interior of the closure body, wherein the side wall has at least in sections an internal thread and a corresponding external thread.

[0135] Further disclosed herein is a device for producing such screw caps by means of thermoforming, in particular a device for carrying out the method according to this disclosure.

[0136] Display closures made of thermoplastic materials, e.g. polyesters or polyolefins, are available in various versions and dimensions. Such display closures are used in particular as closures for disposable or reusable packaging of food, drinks and other products.

[0137] Screw caps for drinks bottles, especially PET bottles, are particularly important due to the quantity required. The production of these screw caps using thermoforming has advantages over production using injection molding, particularly due to the lower material requirements.

[0138] However, in its simplest form, thermoforming is only suitable for producing relatively simple molded bodies that, in particular, do not have undercuts such as a thread. When producing a screw cap using thermoforming, the challenge is to remove the screw cap from the corresponding mold segment after forming without causing any damage.

[0139] Embodiments herein are therefore based on the object of proposing an improved method and an improved device for producing display closures by means of thermoforming.

[0140] This object can be achieved in the method according to this disclosure in that it comprises the following steps:

[0141] Providing a film made of a thermoplastic material and heating the film;

[0142] feeding the film between a lower tool and an upper tool, which are movable relative to one another in an axial direction perpendicular to the film, wherein the lower tool comprises a plurality of rotatable mold segments, the molding surfaces of which have an external thread complementary to the internal thread of the closure body or an internal thread complementary to the external thread of the closure body;

[0143] Closing the lower tool and the upper tool while the film is subjected to a differential pressure in order to deform the film and form the closure bodies on the molding surface of the rotatable mold segments;

[0144] Allow the foil to cool;

[0145] at least partially opening the lower tool and the upper tool while the rotatable mold segments perform a rotation around the axial direction synchronized according to the pitch of the internal thread in order to remove the closure bodies from the mold segments;

[0146] Removing the film with the formed closure body from the lower tool and upper tool; and

[0147] Separating the individual closure bodies from the foil to obtain the screw caps.

[0148] In some embodiments, the method includes the rotation of the rotatable mold segments, which is synchronized with the axial opening movement of the lower and upper tools, so that the mold segments are unscrewed from the closure bodies of the screw closures when opened. The method thus enables the simultaneous production of a large number of closure bodies in a single thermoforming tool. Since the closure bodies are initially still connected to one another via the non-formed area of the film after thermoforming, it would not be possible to remove them from the mold segments by rotating the closure bodies. Only after the film with the formed closure bodies has been removed from the lower tool and upper tool does the separation of the individual closure bodies from the film take place in a subsequent process step.

[0149] During rotation of the rotatable mold segments, the lower tool and the upper tool are opened at least partially until the mold segments are removed from the closure bodies. The upper and lower tools can then be opened completely without rotating the mold segments.

[0150] In the context of this description, the terms "lower tool" and "upper tool" are basically only used to functionally differentiate between the two tool halves, i.e., the lower tool, in contrast to the upper tool, includes the mold segments on which the closure bodies are formed. This doesnot say anything about the orientation of the two tool halves in space, i.e., the lower tool can also be arranged "on top". Likewise, the two tool halves can also be arranged horizontally next to each other, for example.

[0151] When this description refers to the closing or opening of “the lower tool and the upper tool”, this basically means a relative movement of the lower tool and the upper tool away from or towards each other, regardless of whether both tool halves are moving or only one.

[0152] The method according to this disclosure comprises, on the one hand, positive thermoforming, in which the rotatable mold segments correspond to the interior of the closure bodies and their molding surfaces have an external thread that is complementary to the internal thread of the closure body. In addition, the method also comprises negative thermoforming, in which the rotatable mold segments are hollow mold segments and their molding surfaces have an internal thread that is complementary to the external thread of the closure body. In the latter case, the hollow mold segments are "turned off (and not "turned out") of the closure bodies after thermoforming. Even if only the terms "mold segments" and "turn out" are used in the present description for the sake of simplicity, all statements also apply in principle to negative thermoforming with hollow mold segments, unless explicitly stated otherwise.

[0153] The film is subjected to a differential pressure during the closing of the lower tool and upper tool in order to form it on the molding surface of the rotating mold segments, forming the closure bodies. The differential pressure does not necessarily have to be present during the entire axial movement of the two tool halves, but at least in the final phase of the closing movement. To generate the differential pressure, the film is subjected to an overpressure from the upper tool and / or a negative pressure from the lower tool. It can be advantageous if both an overpressure and a negative pressure are applied.

[0154] In the case of positive thermoforming, in which the molding surfaces of the mold segments have an external thread that is complementary to the internal thread of the closure body, the upper tool can have one or more cavities into which the rotatable mold segments can dip when the lower tool and upper tool are closed. A large cavity can be provided into which all the mold segments of the lower tool dip, or one cavity for each individual mold segment. The one or more cavities can be subjected to excess pressure during closing. The areas of the upper tool lying between the cavities can lie sealingly against the film after the two tool halves have been closed, i.e. against the non-formed areas of the film.

[0155] In the case of negative thermoforming, in which the molding surfaces of the hollow mold segments have an internal thread complementary to the external thread of the closure body, the upper tool usually has only one flat contact surface which, after the two tool halves have been closed, lies sealingly against the film, i.e., against the non-formed areas of the film.

[0156] According to an embodiment of this disclosure, a clamping frame can also be provided which surrounds the lower tool in order to fix the film between this clamping frame and the lower tool when the two tool halves are closed before the forming takes place on the molding surfaces of the mold segments. The clamping frame can be spring-mounted on the lower tool in the axial direction.

[0157] To apply the pressure difference to the film, the molding surfaces of the rotatable mold segments can have holes that are subjected to a negative pressure when the lower tool and upper tool are closed. The holes advantageously have a diameter of approximately 0.2 to approximately 0.8 mm. In some embodiments, the holes are arranged in the area of the molding surface of the rotatable mold segments where the cover wall of the closure body is formed.

[0158] It is preferred if the rotatable mold segments are arranged next to one another within the lower tool in at least one row with two or more mold segments each. An arrangement of several mold segments that is as compact as possible allows screw caps to be produced from a given film section with a relatively small amount of residual material. The arrangement of the rotatable mold segments in rows also enables an effective drive mechanism for their synchronized rotation, as will be explained in more detail in connection with the device according to this disclosure.

[0159] In some embodiments of the method, each rotatable mold segment is assigned a rotationally fixed mold segment, on the molding surface of which a section of the side wall of the closure body that does not have an internal thread is formed.

[0160] In some embodiments, the non-rotatable mold segment coaxially surrounds the rotatable mold segment, with the molding surface of the non-rotatable mold segment adjoining the molding surface of the rotatable mold segment in the axial direction downwards, ie in the direction of the lower tool (or upwards in the case of negative thermoforming). Accordingly, the section of the side wall without an internal thread (and without an external thread) is located at the lower end of the side wall of the closure body.

[0161] An annular gap can be formed between the molding surface of the rotatable mold segment and the molding surface of the rotationally fixed mold segment. This gap, which can inparticular have a width of approx. 0.2 to approx. 0.8 mm, can be subjected to a negative pressure during the closing of the lower tool and upper tool, and thus takes on a similar function to the holes in the molding surface of the rotatable mold segment.

[0162] In an embodiment, the molding surface of the rotationally fixed mold segment, on which a section of the side wall is formed, has a plurality of projections or elevations running in the axial direction. These can be distributed at equal intervals around the entire circumference of the rotationally fixed mold segment, but can also be arranged in segments. Since the projections or elevations prevent rotation after thermoforming, corresponding structures of the closure body can only be produced by means of rotationally fixed mold segments. Such a groove or rib structure in a section of the side wall can be advantageous because it leads to a better "grip" when opening and closing the screw cap and thus makes handling easier for the consumer.

[0163] In some embodiments, the molding surface of the non-rotatable mold segment, on which a section of the side wall is formed, is followed by a molding surface running perpendicular to the axial direction, which is aligned with a molding surface of the lower tool located between the mold segments. A section of the film is formed on this molding surface running perpendicular to the axial direction, which can be fully or partially retained as an edge protruding perpendicularly from the side wall when the closure body is separated from the film.

[0164] The molding surface of the rotationally fixed mold segments, which extends perpendicular to the axial direction, can have an annular elevation in order to create an annular groove in the edge of the closure body that protrudes perpendicularly from the side wall when the film is formed. Such a groove can, for example, facilitate the bending of folding tabs that are punched out of the edge that protrudes perpendicularly from the side wall (see below).

[0165] The rotatable mold segment can be mounted so that it can rotate within the non- rotatable mold segment (or outside the rotatable hollow mold segment in the case of negative thermoforming). The bearing can be implemented in particular by means of a plain bearing, a ball bearing or a nail bearing.

[0166] Allowing the film to cool after closing the lower tool and upper tool can be done by means of active cooling. It is particularly effective if the active cooling includes cooling of the rotating mold segments, in which a cooling medium is passed through the interior of the rotating mold segments.

[0167] The individual closure bodies can be separated from the film after they have been removed from the lower tool and upper tool by means of punching. All closure bodies can be punched out at the same time using an appropriate punching tool.

[0168] In an embodiment of the method, the punching is carried out in such a way that the screw cap comprises one or more film sections that protrude essentially perpendicularly outwards from the side wall of the closure body.

[0169] These film sections can in particular be punched out from an edge of the closure body that has been formed on a molding surface of the mold segment that runs perpendicular to the axial direction, as described above.

[0170] The film sections that protrude essentially vertically outwards can be designed as folding tabs that are distributed at equal intervals around the entire circumference of the side wall. In this embodiment of this disclosure, it can be advantageous if the method further comprises the step:

[0171] Folding, bending or creasing the folding tabs into the interior of the closure body in order to provide tamper protection for the screw cap.

[0172] In some embodiments, the method further comprises the step:

[0173] Creating a weakening line along a circumference of the side wall below the internal thread. This step may be carried out before folding, bending or folding the folding tabs into the interior of the closure body.

[0174] Carrying out the two process steps mentioned above enables the production of screw caps that are particularly suitable for tamper-proof closure of drinks bottles: When the bottle is closed, the folding tabs located inside the closure body pass under a ring-shaped projection on the bottle neck. When the bottle is opened, the folding tabs act like a barb, so that the side wall tears along the weakening line and only the part of the closure body located above this line is unscrewed.

[0175] In an embodiment of this disclosure, the method further comprises the step:

[0176] Creating an embossed structure on an outer side of the side wall of the closure body in the section with the thread and / or in a downwardly adjoining section without a thread. This step is carried out before or after the individual closure bodies are separated from the film.

[0177] The embossed structure can comprise grooves running in the axial direction, which are distributed in particular at equal intervals along the entire circumference of the side wall. Alternatively, the grooves can also be arranged only in segments. The creation of such an embossed structure before or after the closure body is separated from the film can be carried out alternatively or in addition to the creation of grooves during thermoforming by means of a rotationally fixed mold segment, as described above. In this case too, the groove or rib structure serves to improve the "grip" of the screw cap.

[0178] The embossed structure can be produced with an embossed tool which acts axially from above or radially from the outside on the side wall. As already mentioned, the embossed structure can be produced in the section with the thread and / or in a section without a thread that follows downwards. In the former case, the embossed structure is produced in particular on the tooth flanks of the external thread of the closure body. The external diameter of this external thread advantageously corresponds approximately to the diameter of the closure body in the section without a thread.

[0179] In principle, any material suitable for thermoforming can be used as the thermoplastic material of the film within the scope of this disclosure. Preference is given to thermoplastic polymers selected from polyesters (such as PET), polyolefins (such as PE) and other chain polymers (such as PS). The thermoplastic material can be selected from polyethylene terephthalate (PET), polyethylene furanoate (PEF), polybutylene terephthalate (PBT), polycarbonate (PC), polyolefins, in particular polyethylene (PE) and polypropylene (PP), polystyrene (PS), styreneacrylonitrile copolymers (SAN), acrylonitrilebutadiene-styrene copolymers (ABS), thermoplastic elastomers (TPE), in particular TPE-O, TPEU and TPE-S, ethylene-vinyl alcohol copolymer (EVOH), polyvinyl alcohol (PVOH) and copolymers and mixtures thereof.

[0180] In some embodiments, the screw caps is made from the same material as the container to be closed. This offers a significant advantage when recycling the containers, as there is no need for the laborious separation of the materials of the screw caps and the containers. The method according to this disclosure is therefore particularly suitable for producing screw caps made from PET for closing PET drinks bottles.

[0181] Depending on the type and size of the screw cap, the film can have a thickness in the range of approx. 0.1 to approx. 2.0 mm, in some embodiments from approx. 0.2 to approx. 1.4 mm, in some embodiments from approx. 0.3 to approx. 0.9 mm, and in some embodiments from approx. 0.4 to approx. 0.6 mm. Starting materials with a thickness of approx. 1.5 mm or more aresometimes also referred to as "sheets", but in the context of the present description the term "film is used for all materials regardless of their thickness.

[0182] In some embodiments, the screw cap produced according to this disclosure, in particular as a screw cap for drinks bottles, has a diameter of the lid wall of approximately 2 to approximately 3 cm and a height of the side wall of approximately 1 to approximately 2 cm . However, the method is equally suitable for the production of screw caps for other types of containers, such as cans or buckets, even with significantly larger dimensions.

[0183] An underlying object that can be achieved in the device according to this disclosure in that it comprises the following: a lower tool with a plurality of rotatable mold segments, the molding surfaces of which have an internal thread complementary to the external thread of the closure body or an external thread complementary to the internal thread of the closure body; and an upper tool, wherein the lower tool and the upper tool are movable relative to each other in an axial direction perpendicular to the film.

[0184] The rotatable mold segments of the lower tool are designed to perform a rotation around the axial direction synchronized according to the pitch of the internal thread when the lower tool and upper tool are opened in order to remove the closure bodies from the mold segments, as described in connection with the method according to this disclosure.

[0185] The device according to this disclosure is particularly suitable for carrying out the method according to this disclosure, wherein various advantages and some embodimentss of the device have already been described in connection with the method.

[0186] In the case of positive thermoforming, the molding surfaces of the mold segments have an external thread complementary to the internal thread of the closure body, and the upper tool has one or more cavities into which the rotatable mold segments can be immersed when the lower tool and upper tool are closed.

[0187] In some embodiments of the device, the lower tool further comprises a plurality of rotationally fixed mold segments, wherein a rotationally fixed mold segment coaxially surrounds a rotatable mold segment and the molding surface of the rotationally fixed mold segment adjoins the molding surface of the rotatable mold segment in the axial direction downwards, ie in the direction of the lower tool (or upwards in the case of negative thermoforming).

[0188] There are various possibilities within the scope of this disclosure for driving the rotatable mold segments during synchronized rotation. On the one hand, it can be provided thateach rotatable mold segment is driven by an individual drive device, in particular by an electric motor.

[0189] According to some embodiments, the rotatable mold segments are arranged next to one another within the lower tool in at least one row with two or more mold segments each. A corresponding arrangement of the mold segments enables efficient drive by means of only one or fewer drive devices.

[0190] In some embodiments, the rotating mold segments are each driven via an axial drive shaft by a drive unit arranged below the mold segment. These drive units can be in turn driven via toothed belts or chains. Driving several mold segments via a single toothed belt or chain automatically synchronizes them with one another.

[0191] In some embodiments, within a row or two adjacent rows of rotatable mold segments, every second drive unit is driven by a first toothed belt or a first chain, and the other drive units within this row(s) are driven by a second toothed belt or a second chain. The second toothed belt or the second chain can be arranged axially below the first toothed belt or the second chain and can be guided around the drive units in opposite directions, with the toothed belts or chains being redirected around the drive units not driven by them in freewheeling mode. This arrangement is characterized by a very small space requirement for the drive units and thus enables a dense arrangement of the rotatable mold segments.

[0192] In the arrangement described above, it can be advantageous if the first toothed belt or the first chain and the second toothed belt or the second chain are each driven by the same drive device, in particular by an electric motor.

[0193] Thus, only one drive unit is required to drive several rotatable mold segments in one or two rows, e.g. 2x2, 2x4 or 2x6 mold segments.

[0194] Instead of toothed belts or chains, a number of other possibilities are conceivable and known to those skilled in the art for driving several mold segments simultaneously and synchronously. For example, the drive units of four rotatable mold segments each, which are arranged according to the corners of a square, can be driven by a gear arranged in the center of the square.

[0195] These and other advantages of this disclosure are described in more detail using the following embodiments with reference to the drawings.

[0196] Figures 8A to 8E show schematically the sequence of the method according to this disclosure for producing screw caps by means of thermoforming. The method is carried out using a device according to this disclosure, which is shown schematically and in a highly simplified cross-sectional view in the figures.

[0197] The device 10 according to this disclosure for producing screw caps comprises a lower tool 12 and an upper tool 14, which in Figure 8A are in an open position at the beginning of the method according to this disclosure. In this case, the upper tool 14 is located above the lower tool 12 in relation to the spatial directions. However, this is not mandatory; an inverted arrangement or an arrangement rotated by 90° is also possible.

[0198] In a first step of the method, a film 16 made of a thermoplastic material, for example a PET film with a thickness of approximately 0.4 to approximately 0.6 mm, is provided as the starting material for producing the screw caps and is then fed between the lower tool 12 and the upper tool 14. The orientation of the film 16 is perpendicular to an axial direction 18 in which the lower tool 12 and the upper tool 14 are movable relative to one another.

[0199] The film 16 is heated before, during or after feeding to a temperature that is suitable for plastic deformation of the film. In the case of a film made of PET, this can be heated to a temperature of approx. 120 °C, for example.

[0200] The lower tool 12 and the upper tool 14 of the device 10 are now partially closed, i.e. moved towards each other in the axial direction 18 until an edge area of the film 16 is fixed between the upper tool 14 and a clamping frame 20 (Figure 8B). The clamping frame 20 surrounds the lower tool 12 and is mounted thereon so that it can move in the axial direction 18 by means of spring elements 22. At this point in time, the film 16 has no contact with the lower tool 12.

[0201] In a further step of the method, which is shown in Figure 8C, the lower tool 12 and the upper tool 14 close completely. The film 16 is formed on a plurality of rotatable mold segments 24 of the lower tool 12. The rotatable mold segments 24 have a molding surface 26 with an external thread 28, which corresponds to the internal thread of the screw caps to be produced. When the lower tool 12 and the upper tool 14 are closed, the rotatable mold segments 24 each dip into cavities 30 in the upper tool 14, with the areas 32 of the upper tool 14 lying between the cavities 30 resting sealingly against the film 16.

[0202] During the forming process, the film 16 is subjected to a differential pressure, in particular to an overpressure in the cavities 30 and a negative pressure from the lower tool 12. Thisnegative pressure is generated by holes in the rotatable mold segments 24 (not shown in Figures 8 A to 8E).

[0203] After the film 16 has been formed to form closure bodies 34 of the screw caps to be produced, the lower tool 12 and the upper tool 14 are partially opened, as shown in Figure 8D. During this first phase of the opening movement, the rotatable mold segments 24 rotate around the axial direction 18, with this rotation being synchronized with the opening movement in accordance with the pitch of the thread 28. The rotatable mold segments 24 are thus rotated out of the closure bodies 34 in order to be able to remove them from the mold segments 24 without causing any damage.

[0204] The rotation of the rotatable mold segments 24 is driven by drive units 36, which are only indicated in Figures 8A to 8E.

[0205] After the rotatable mold segments 24 have been unscrewed from the closure bodies 34, the lower tool 12 and the upper tool 14 are opened completely, as shown in Figure 8E. The film 16 with the formed closure bodies 34 can then be removed from the device 10. Finally, the screw caps can be obtained by separating the individual closure bodies 34 from the film 16, in particular by means of punching (not shown in the figures).

[0206] An embodiment of a rotatable mold segment 24, which can be used in the device 10 according to this disclosure, is shown in detail in Figures 9 and 10 (in perspective and as a sectional view), namely as part of an assembly 38, which in addition to the rotatable mold segment 24 also includes a rotationally fixed mold segment 40, which coaxially surrounds the rotatable mold segment. Figure 11 shows a perspective view of a screw cap 42, which can be produced with a device according to this disclosure.

[0207] The rotatable mold segment 24 comprises a molding surface 26, in the upper region of which the cover wall 44 of the closure body 34 of the screw cap 42 is formed. In this upper region of the molding surface 26, holes 46 are provided in the rotatable mold segment 24 in order to be able to impact the film 16 with a negative pressure during forming. The molding surface 26 of the rotatable mold segment 24 also has an external thread 28, on which the thread 48 of the closure body 34 (ie its internal thread) is formed. The closure body 34 has the thread 48 in an upper region of the side wall 50.

[0208] A molding surface 52 of the non-rotatable mold segment 40 adjoins the molding surface 26 of the rotatable mold segment 24 with the external thread 28 downwards in the axialdirection. This molding surface 52 has projections 54 that are distributed around the entire circumference of the non-rotatable mold segment 40. When the film 16 is formed, these projections 54 create a rib structure in a lower region of the side wall 50 of the closure body 34. Such a rib structure, which leads to a better "grip" of the screw cap 42, can only be created with a non- rotatable mold segment 40.

[0209] An annular gap 56 is formed between the molding surface 26 of the rotatable mold segment 24 and the molding surface 52 of the rotationally fixed mold segment 40, which can have a width of approximately 0.2 mm, for example. This annular gap 56 can be subjected to a negative pressure when the film 16 is formed and then fulfills a similar function to the holes 46.

[0210] The molding surface 52 with the projections 54 is followed by a molding surface 58 of the rotationally fixed mold segment 40, which extends perpendicularly to the axial direction 18 and on which a region of the film 16 is formed, which, after the closure body 34 has been punched out, forms an edge 60 of the closure body 34 that projects perpendicularly outwards from the side wall 50. This molding surface 58 also has holes 46 that can be subjected to a negative pressure. In addition, the molding surface 58 has an annular projection 62, through which an annular groove (seen from below) is created in the edge 60 of the closure body 34 when the film 16 is formed.

[0211] The rotatable mold segment 24 extends downwards within the non-rotatable mold segment 40 and has a connecting region 66 at its lower end, via which the rotatable mold segment 40 can be connected to a drive device or a drive unit.

[0212] The rotatable mold segment 24 has an axial bore 68 in its interior through which a coolant (e.g., water) can be passed. This enables active cooling of the film 16 after forming. A separating strip 78 extending in the bore 68 divides the film into a flow area and a return area for the coolant.

[0213] The rotatable mold segment 24 is rotatably mounted within the rotationally fixed mold segment. In the embodiment shown, the bearing is carried out by means of a plain bearing 70 made of a solid lubricant, such as graphite.

[0214] The screw cap 42 shown in Figure 11, which can be produced using the method according to this disclosure, has essentially already been described in connection with the assembly 38 used to produce it. The closure body 34 of the screw cap 42 has a cover wall 44 and a side wall 50 with a thread 48. Furthermore, the closure body 34 in the embodiment shown has a relatively narrow edge 60, which was formed on the molding surface 58 of the non-rotatable moldsegment 40 and then punched out. Alternatively, when the closure body 34 is separated from the film 16, several folding tabs can be punched out of a wider edge 60, which are evenly distributed around the entire circumference of the side wall 50 of the closure body 34 (not shown in the figure). These folding tabs are then bent into the interior of the closure body 34 and form a tamper protection for the screw cap 42. Bending the folding tabs is facilitated by the annular groove (seen from below) in the edge 60, the production of which was described in connection with Figures 9 and 10. Furthermore, the screw cap 42 can have a rib structure in the lower region 64 of the side wall 50 (not shown in the figure), the production of which was also described in connection with Figures 9 and 10.

[0215] Figure 12 shows a top view of part of a lower tool 12 of a device 10 according to this disclosure. The figure shows in particular the drive mechanism for the rotatable mold segments 24, which is arranged below the rotatable mold segments 24 and the rotationally fixed mold segments 40.

[0216] In the embodiment of the device 10 shown in Figure 12, the lower tool 12 comprises a total of 36 rotatable mold segments, which are arranged in 6 rows (vertically oriented in the figure) with 6 mold segments each. The 36 drive units 74 are arranged accordingly, each of which drives a rotatable mold segment 24 via an axial drive shaft 76, i.e. sets it in rotation synchronously with the opening movement of the lower tool 12 and upper tool 14 during the corresponding phase of the manufacturing process according to this disclosure. In this example, the drive shafts 76 each have a square receptacle into which the connecting area 66 of the rotatable mold segment 24 can engage in a formfitting manner according to Figures 9 and 10.

[0217] Each drive unit 74 is also assigned a separating strip 78 which, after the drive shaft 76 is connected to the rotatable mold segment 24, extends upwards within the axial bore 68 of the rotatable mold segment 24. This separating strip 78 divides the axial bore 68 into a supply area and a return area for the coolant, these areas being connected at the upper end of the axial bore 68. The coolant is supplied and discharged from below by the drive units 74 (not shown in the figure).

[0218] Within two adjacent rows of drive units 74, every second drive unit 74 is driven by a first toothed belt 80, and the remaining drive units 74 of these two rows are driven by a second toothed belt 82. The second toothed belt 82 is arranged axially below the first toothed belt 80. The toothed belts 80 and 82 are guided around the drive units 74 of the two adjacent rows in such a way that the first (upper) toothed belt 80 drives the first, third and fifth drive units 74 (from below) of the first row (right) and the second, fourth and sixth drive units 74 of the second row (left) inthe same direction, while the second (lower) toothed belt 82 drives the second, fourth and sixth drive units 74 of the first row and the first, third and fifth drive units 74 of the second row in the same direction. For this drive, each drive unit 74 comprises a gear 84 at the level of the first toothed belt 80 or the second toothed belt 82.

[0219] The first toothed belt 80 or the second toothed belt 82 is redirected in freewheel mode around those drive units 74 which are not driven by it.

[0220] The two toothed belts 80 and 82 are jointly driven by a drive device 86, in this case in the form of an electric motor. In total, three drive devices 86 are present in this embodiment in order to drive the drive units 74 of two adjacent rows each.

[0221] The drive mechanism according to Figure 12 allows for a simultaneous and synchronous drive of several drive units 74 with only one drive device 86. Above all, however, the described guidance of the toothed belts 80 and 82 enables a very space-saving arrangement of the drive units 74 and thus of the rotatable mold segments 24, whereby the residual film material is minimized during the production of the screw caps.

[0222] List of reference symbols in FIGS. 8-12:

[0223] 10 Device for producing screw caps

[0224] 12 Lower tool

[0225] 14 Upper tool

[0226] 16 Film made of thermoplastic material

[0227] 18 Axial direction

[0228] 20 clamping frames

[0229] 22 Spring element

[0230] 24 rotatable s mold segment

[0231] 26 Impression area

[0232] 28 External thread of the mold segment

[0233] 30 cavities

[0234] 32 areas between cavities

[0235] 34 Locking body

[0236] 36 Drive unit

[0237] 38 Assembly

[0238] 40 non-rotating mold segment

[0239] 42 screw cap

[0240] 44 Lid wall

[0241] 46 holes

[0242] 48 Thread of the locking body

[0243] 50 side wall

[0244] 52 Impression area

[0245] 54 projections

[0246] 56 Annular gap

[0247] 58 Impression area

[0248] 60 Rand

[0249] 62 annular projection

[0250] 64 lower area

[0251] 66 Connection area

[0252] 68 axial bore

[0253] 70 plain bearings

[0254] 74 Drive unit

[0255] 76 Drive shaft

[0256] 78 Divider strips

[0257] 80 first timing belt

[0258] 82 second timing belt

[0259] 84 Gear

[0260] 86 Drive device

[0261] The processes described in this patent has significant application prospects in the manufacturing industry, particularly in the production of plastic containers and packaging. Given the increasing demand for sustainable and cost-effective packaging solutions, the ability to effectively thermoform PET caps without causing damage or deformation could revolutionize the way these products are produced. Moreover, the thermoforming processes herein also find application in the pharmaceutical and food industries where consistent and reliable packaging is of utmost importance. By enabling the creation of high-quality, consistent PET caps, the present thermoforming processes can help companies in these sectors to improve product quality, reduce waste, and increase efficiency in their production processes. Furthermore, the processes provided herein can be adapted for use in other areas of plastics forming, such as injection molding and compression molding. This opens up new opportunities for thermoforming in the production of complex, precision-engineered plastic parts.

[0262] In terms of market demand, there is a growing need for innovative solutions in the packaging industry. As consumers become more environmentally conscious, there is a pressing need for sustainable packaging solutions that are both cost-effective and efficient. The ability to effectively thermoform PET caps can meet this demand, providing a more sustainable and cost- effective alternative to traditional packaging materials. Overall, the thermoforming processes described herein have significant application prospects and market demand, particularly in the packaging industry and related sectors. Overcoming the challenges long associated with thermoforming PET caps, the thermoforming processes disclosed herein can lead to significant improvements in product quality and efficiency, making for a valuable asset in today’s manufacturing landscape.

[0263] While the thermoforming process has been described in terms of particular variations and illustrative figures, those of ordinary skill in the art will recognize that the process is notlimited to the variations or figures described. In addition, where methods and steps described above indicate certain events occurring in certain order, those of ordinary skill in the art will recognize that the ordering of certain steps may be modified. Additionally, certain of the steps may be performed concurrently in a parallel process, when possible, as well as performed sequentially as described above. To the extent there are variations of the thermoforming process, which are within the spirit of the disclosure or equivalent to the process found in the claims, it is the intent that this patent will cover those variations as well. Therefore, the present disclosure is to be understood as not limited by the specific embodiments described herein, but only by scope of the appended claims.Illustrative Embodiments

[0264] Embodiment 1. A process for forming threads inside a thermoformed PET container closure, comprising:

[0265] heating a thermoplastic material in a thermoforming machine;

[0266] thermoforming the thermoplastic material into a closure;

[0267] cooling the closure in the thermoforming machine;

[0268] removing the closure from a mold comprising the thermoforming machine by rotating the mold portion forming the threads;

[0269] applying clearance to ensure smooth removal of the closure; and

[0270] lifting the closure at an axial rate timed with the rotation of the thread component.

[0271] Embodiment 2. The process of Embodiment 1, wherein heating the thermoplastic material includes providing any of HDPE, PET, PHA, PLA or any type of polymer that is suitable for forming closures.

[0272] Embodiment s. The process of Embodiment 1, wherein heating the thermoplastic material includes heating the thermoplastic material to a temperature that allows the thermoplastic material to become more flexible and easier to shape.

[0273] Embodiment 4. The process of Embodiment 1, wherein heating the thermoplastic material includes heating the thermoplastic material to a temperature ranging between about 80°C and about 120°C.

[0274] Embodiment s. The process of Embodiment 1, wherein thermoforming includes injection molding or compression molding a HDPE or PET material.

[0275] Embodiment 6. The process of Embodiment 1, wherein thermoforming the thermoplastic material includes configuring the mold to create desired features on the inside of the closure.

[0276] Embodiment 7. The process of Embodiment 1, wherein thermoforming the thermoplastic material includes configuring the mold to accommodate the formation of threads on the inside of the closure.

[0277] Embodiment s. The process of Embodiment 1, wherein thermoforming the thermoplastic material includes applying pressure to the thermoplastic material using the thermoforming machine.

[0278] Embodiment 9. The process of Embodiment 1, wherein thermoforming the thermoplastic material includes applying a pressure that is sufficient to shape the thermoplastic material into the closure but not so high as to cause damage to the PET material.

[0279] Embodiment 10. The process of Embodiment 1, wherein cooling the closure includes allowing the closure to cool to room temperature in the thermoforming machine.

[0280] Embodiment 11. The process of Embodiment 1, wherein cooling the closure includes providing water cooling channels in the mold to cool the closure.

[0281] Embodiment 12. The process of Embodiment 11, wherein providing water cooling channels includes forming a 3D network of cooling channels to reduce the pitch between individual forming portions of the mold.

[0282] Embodiment 13. The process of Embodiment 1, wherein removing the closure includes using a controlled rotation system to ensure consistent and accurate rotation of the threads.

[0283] Embodiment 14. The process of Embodiment 13, wherein using the controlled rotation system includes using any one or more of a servo, a belt, a chain drive system, or any combination thereof.

[0284] Embodiment 15. The process of Embodiment 14, wherein using the controlled rotation system includes operating the controlled rotation system at a speed ranging between about 10 RPM and about 20 RPM.

[0285] Embodiment 16. The process of Embodiment 1, wherein applying clearance includes using a clearance mechanism to ensure a thread path follows the contour of the rotation as the closure is removed from the mold.

[0286] Embodiment 17. The process of Embodiment 16, wherein using the clearance mechanism includes providing clearance along the threads to enable smooth removal of the closure from the mold.

[0287] Embodiment 18. The process of Embodiment 16, wherein using the clearance mechanism includes allowing for vents or other interruptions in the closure.

[0288] Embodiment 19. The process of Embodiment 1, wherein lifting the closure includes using a timing mechanism to lift the closure at an axial rate that prevents deformation and unwanted height variation of the closure.

[0289] Embodiment 20. The process of Embodiment 19, wherein using the timing mechanism includes lifting the closure at an axial rate of 1-2 mm / s.

[0290] Embodiment 21. A method for producing screw caps by means of thermoforming, wherein the screw caps each comprise a closure body with a cover wall and a side wall which define an interior of the closure body, wherein the side wall has at least in sections an internal thread and a corresponding external thread, and wherein the method comprises the following steps:

[0291] a. Providing a film made of a thermoplastic material and heating the film;

[0292] b. feeding the film between a lower tool and an upper tool, which are movable relative to one another in an axial direction perpendicular to the film, wherein the lower tool comprises a plurality of rotatable mold segments, the molding surfaces of which have an external thread complementary to the internal thread of the closure body or an internal thread complementary to the external thread of the closure body;

[0293] c. Closing the lower tool and the upper tool while the film is subj ected to a differential pressure in order to deform the film and form the closure bodies on the molding surface of the rotatable mold segments;

[0294] d. Allow the foil to cool;

[0295] e. at least partially opening the lower tool and the upper tool while the rotatable mould segments perform a rotation around the axial direction synchronized according to the pitch of the internal thread in or- der to remove the closure bodies from the mould segments;

[0296] f. Removing the film with the formed closure bodies from the lower tool and upper tool; and

[0297] g. Separating the individual closure bodies from the foil to obtain the screw caps.

[0298] Embodiment 22. The method according to Embodiment 21, wherein the molding surfaces of the mold segments have an external thread complementary to the internal thread of the closure body, and wherein the upper tool has one or more cavities into which the rotatable mold segments can dip when the lower tool and upper tool are closed, and which are subjected to an overpressure during closing.

[0299] Embodiment 23. The method according to Embodiment 21 or 22, wherein the molding surfaces of the rotatable mold segments have bores which are subjected to a negative pressure during the closing of the lower tool and upper tool.

[0300] Embodiment 24. The method according to Embodiment 23, wherein the bores are arranged in the region of the molding surface of the rotatable mold segments at which the cover wall of the closure body is formed.

[0301] Embodiment 25. The method according to one of the preceding Embodiments, wherein the rotatable mold segments are arranged next to one another within the lower tool in at least one row with two or more mold segments each.

[0302] Embodiment 26. The method according to one of the preceding Embodiments, wherein each rotatable mold segment is assigned a rotationally fixed mold segment, on the molding surface of which a portion of the side wall of the closure body which does not have an internal thread is formed.

[0303] Embodiment 27. The method according to Embodiment 26, wherein the non-rotatable mold segment coaxially surrounds the rotatable mold segment and the molding surface of the non- rotatable mold segment adjoins the molding surface of the rotatable mold segment downwards in the axial direction.

[0304] Embodiment 28. The method according to Embodiment 27, wherein an annular gap is formed be- tween the molding surface of the rotatable mold segment and the mold- ing surfaceof the non-rotatable mold segment, which gap is subjected to a negative pressure during the closing of the lower tool and upper tool.

[0305] Embodiment 29. The method according to one of Embodiments 26 to 28, wherein the molding surface of the rotationally fixed mold segment, on which a portion of the side wall is formed, has a plurality of projections or elevations extending in the axial direction, which are distributed at equal intervals around the entire circumference of the rotationally fixed mold segment.

[0306] Embodiment 30. The method according to one of Embodiments 26 to 29, wherein the molding surface of the rotationally fixed mold segment, on which a portion of the side wall is formed, is followed by a molding surface running perpendicular to the axial direction, which is aligned with a molding surface of the lower tool located between the mold segments.

[0307] Embodiment 31. The method according to Embodiment 30, wherein the molding surface of the rotationally fixed mold segments extending perpendicular to the axial direction has an annular elevation.

[0308] Embodiment 32. The method according to one of Embodiments 26 to 31, wherein the rotatable mold segment is rotatably mounted within the rotationally fixed mold segment, in particular by means of a plain bearing, a ball bearing or a nail bearing.

[0309] Embodiment 33. The method according to one of the preceding Embodiments, wherein the cooling of the film after closing the lower tool and upper tool takes place by means of active cooling.

[0310] Embodiment 34. The method according to Embodiment 33, wherein the active cooling comprises cooling the rotatable mold segments by passing a cooling medium through the interior of the rotatable mold segments.

[0311] Embodiment 35. The method according to one of the preceding Embodiments, wherein the individual closure bodies are separated from the film by means of punching.

[0312] Embodiment 36. The method according to Embodiment 35, wherein the punching is carried out such that the screw closure comprises one or more film sections which protrude substantially perpendicularly outward from the side wall of the closure body.

[0313] Embodiment 37. The method according to Embodiment 36, wherein the substantially vertically outwardly projecting film sections are designed as folding tabs which are distributed at equal intervals around the entire circumference of the side wall.

[0314] Embodiment 38. The method of Embodiment 37, further comprising the step:

[0315] a. folding, bending or creasing the folding tabs into the interior of the closure body in order to provide tamper protection for the screw cap.

[0316] Embodiment 39. The method according to one of the preceding Embodiments, further comprising the step:

[0317] a. Creating a weakening line along a circumference of the side wall be- low the internal thread - this step may be carried out before folding, bending or folding the folding tabs into the interior of the closure body.

[0318] Embodiment 40. The method according to one of the preceding Embodiments, further comprising the step:

[0319] a. creating an embossed structure on an outer side of the side wall of the closure body in the section with the thread and / or in a downwardly adjoining section without a thread - this step is carried out before or after the individual closure bodies are separated from the film.

[0320] Embodiment 41. The method according to Embodiment 40, wherein the embossed structure comprises axially extending grooves, which are distributed at equal intervals along the entire circumference of the side wall.

[0321] Embodiment 42. The method according to Embodiment 40 or 41, wherein the embossed structure is produced with an embossing tool which acts axially from above or radially from the outside on the side wall.

[0322] Embodiment 43. The method according to one of the preceding Embodiments, wherein the thermo- plastic material is selected from polyethylene terephthalate (PET), polyethylene furanoate (PEF), polybutylene terephthalate (PBT), polycarbonate (PC), polyolefins, in particular polyethylene (PE) and polypropylene (PP), polystyrene (PS), styrene-acrylonitrile copolymers (SAN), acrylonitrile-butadiene- styrene copolymers (ABS), thermoplastic elastomers (TPE), in particular TPE-O, TPEU and TPE-S, ethylene-vinyl alcohol copolymer (EVOH), polyvinyl alcohol (PVOH) and their copolymers and mixtures.

[0323] Embodiment 44. The method according to any one of the preceding Embodiments, wherein the film has a thickness in the range of about 0.1 to about 2.0 mm, from about 0.2 to about 1.4 mm, from about 0.3 to about 0.9 mm, or from about 0.4 to about 0.6 mm.

[0324] Embodiment 45. The method according to one of the preceding Embodiments, wherein the screw closure has a diameter of the lid wall of about 2 to about 3 cm and a height of the side wall of about 1 to about 2 cm.

[0325] Embodiment 46. The device for producing screw caps by thermoforming a film made of a thermoplastic material, wherein the screw caps each comprise a closure body with a cover wall and a side wall which define an interior of the closure body, wherein the side wall has at least in sections an internal thread and a corresponding external thread, and wherein the device comprises:

[0326] a. a lower tool with a plurality of rotatable mold segments, the molding surfaces of which have an internal thread complementary to the ex- temal thread of the closure body or an external thread complementary to the internal thread of the closure body; and

[0327] b. an upper tool, wherein the lower tool and the upper tool are movable relative to each other in an axial direction perpendicular to the film.

[0328] Embodiment 47. The device according to Embodiment 46, wherein the molding surfaces of the mold segments have an external thread complementary to the internal thread of the closure body, and wherein the upper tool has one or more cavities into which the rotatable mold segments can dip when the lower tool and upper tool are closed.

[0329] Embodiment 48. The device according to Embodiment 46 or 47, wherein the lower tool further comprises a plurality of rotationally fixed mold segments, and wherein a rotationally fixed mold segment coaxially surrounds a rotatable mold segment and the molding surface of the rotationally fixed mold segment adjoins the molding surface of the rotatable mold segment downwards in the axial direction.

[0330] Embodiment 49. The device according to one of Embodiments 46 to 48, wherein each rotatable mold segment is driven by a single drive device, in particular by an electric motor.

[0331] Embodiment 50. The device according to one of Embodiments 46 to 49, wherein the rotatable mold segments are arranged next to one another within the lower tool in at least one row with two or more mold segments each .

[0332] Embodiment 51. The device according to Embodiment 50, wherein the rotatable mold segments are each driven via an axial drive shaft by a drive unit arranged below the mold segment.

[0333] Embodiment 52. The device according to Embodiment 51 , wherein the drive units are driven via toothed belts or chains.

[0334] Embodiment 53. Apparatus according to Embodiment 52, wherein within one row or two adj a- cent rows of rotatable mold segments every second drive unit is driven by a first toothed belt or a first chain, and wherein the respective other drive units within this row(s) are driven by a second toothed belt or a second chain.

[0335] Embodiment 54. The device according to Embodiment 53, wherein the second toothed belt or the second chain is arranged in the axial direction below the first toothed belt or the second chain and is guided in opposite directions around the drive units, and wherein the toothed belts or chains are deflected in freewheel mode around the drive units not driven by them.

[0336] Embodiment 55. The device according to Embodiment 53 or 54, wherein the first toothed belt or the first chain and the second toothed belt or the second chain are each driven by the same drive device, in particular by an electric motor.

[0337] Embodiment 56. Use of the device according to one of Embodiments 46 to 55 for carrying out the according to one of Embodiments 21 to 45.

[0338] Embodiment 57. A process for forming threads inside a thermoformed PET container closure, comprising:

[0339] heating a thermoplastic material in a thermoforming machine;

[0340] thermoforming the thermoplastic material into a closure;

[0341] cooling the closure in the thermoforming machine;

[0342] removing the closure from a mold comprising the thermoforming machine by rotating the mold portion forming the threads;

[0343] applying clearance to ensure smooth removal of the closure; and

[0344] lifting the closure at an axial rate timed with the rotation of the thread component.

[0345] Embodiment 58. The process of Embodiment 57, wherein heating the thermoplastic material includes providing any of HDPE, PET, PHA, PLA or any type of polymer that is suitable for forming closures.

[0346] Embodiment 59. The process of Embodiment 57, wherein heating the thermoplastic material includes heating the thermoplastic material to a temperature that allows the thermoplastic material to become more flexible and easier to shape.

[0347] Embodiment 60. The process of Embodiment 57, wherein heating the thermoplastic material includes heating the thermoplastic material to a temperature ranging between about 80°C and about 120°C.

[0348] Embodiment 61. The process of Embodiment 57, wherein thermoforming includes injection molding or compression molding a HDPE or PET material.

[0349] Embodiment 62. The process of Embodiment 57, wherein thermoforming the thermoplastic material includes configuring the mold to create desired features on the inside of the closure.

[0350] Embodiment 63. The process of Embodiment 57, wherein thermoforming the thermoplastic material includes configuring the mold to accommodate the formation of threads on the inside of the closure.

[0351] Embodiment 64. The process of Embodiment 57, wherein thermoforming the thermoplastic material includes applying pressure to the thermoplastic material using the thermoforming machine.

[0352] Embodiment 65. The process of Embodiment 57, wherein thermoforming the thermoplastic material includes applying a pressure that is sufficient to shape the thermoplastic material into the closure but not so high as to cause damage to the PET material.

[0353] Embodiment 66. The process of Embodiment 57, wherein cooling the closure includes allowing the closure to cool to room temperature in the thermoforming machine.

[0354] Embodiment 67. The process of Embodiment 57, wherein cooling the closure includes providing water cooling channels in the mold to cool the closure.

[0355] Embodiment 68. The process of Embodiment 67, wherein providing water cooling channels includes forming a 3D network of cooling channels to reduce the pitch between individual forming portions of the mold.

[0356] Embodiment 69. The process of Embodiment 57, wherein removing the closure includes using a controlled rotation system to ensure consistent and accurate rotation of the threads.

[0357] Embodiment 70. The process of Embodiment 69, wherein using the controlled rotation system includes using any one or more of a servo, a belt, a chain drive system, or any combination thereof.

[0358] Embodiment 71. The process of Embodiment 70, wherein using the controlled rotation system includes operating the controlled rotation system at a speed ranging between about 10 RPM and about 20 RPM.

[0359] Embodiment 72. The process of Embodiment 57, wherein applying clearance includes using a clearance mechanism to ensure a thread path follows the contour of the rotation as the closure is removed from the mold.

[0360] Embodiment 73. The process of Embodiment 72, wherein using the clearance mechanism includes providing clearance along the threads to enable smooth removal of the closure from the mold.

[0361] Embodiment 74. The process of Embodiment 72, wherein using the clearance mechanism includes allowing for vents or other interruptions in the closure.

[0362] Embodiment 75. The process of Embodiment 57, wherein lifting the closure includes using a timing mechanism to lift the closure at an axial rate that prevents deformation and unwanted height variation of the closure.

[0363] Embodiment 76. The process of Embodiment 75, wherein using the timing mechanism includes lifting the closure at an axial rate of 1-2 mm / s.

Claims

CLAIMSWhat is claimed is:

1. A process for forming threads inside a thermoformed PET container closure, comprising: heating a thermoplastic material in a thermoforming machine; thermoforming the thermoplastic material into a closure; cooling the closure in the thermoforming machine; removing the closure from a mold comprising the thermoforming machine by rotating the mold portion forming the threads; applying clearance to ensure smooth removal of the closure; and lifting the closure at an axial rate timed with the rotation of the thread component.

2. The process of claim 1, wherein heating the thermoplastic material includes providing any of HDPE, PET, PHA, PL A or any combination thereof.

3. The process of claim 1, wherein heating the thermoplastic material includes heating the thermoplastic material to a temperature that allows the thermoplastic material to become more flexible and easier to shape.

4. The process of claim 1, wherein heating the thermoplastic material includes heating the thermoplastic material to a temperature ranging between about 80°C and about 120°C.

5. The process of claim 1 , wherein thermoforming includes inj ection molding or compression molding a HDPE or PET material.

6. The process of claim 1, wherein thermoforming the thermoplastic material includes configuring the mold to create desired features on the inside of the closure.

7. The process of claim 1, wherein thermoforming the thermoplastic material includes configuring the mold to accommodate the formation of threads on the inside of the closure.

8. The process of claim 1, wherein thermoforming the thermoplastic material includes applying pressure to the thermoplastic material using the thermoforming machine.

9. The process of claim 1, wherein thermoforming the thermoplastic material includes applying a pressure that is sufficient to shape the thermoplastic material into the closure but not so high as to cause damage to the PET material.

10. The process of claim 1, wherein cooling the closure includes allowing the closure to cool to room temperature in the thermoforming machine.

11. The process of claim 1, wherein cooling the closure includes providing water cooling channels in the mold to cool the closure.

12. The process of claim 11, wherein providing water cooling channels includes forming a 3D network of cooling channels to reduce the pitch between individual forming portions of the mold.

13. The process of claim 1, wherein removing the closure includes using a controlled rotation system to ensure consistent and accurate rotation of the threads.

14. The process of claim 13, wherein using the controlled rotation system includes using any one or more of a servo, a belt, a chain drive system, or any combination thereof.

15. The process of claim 14, wherein using the controlled rotation system includes operating the controlled rotation system at a speed ranging between about 10 RPM and about 20 RPM.

16. The process of claim 1, wherein applying clearance includes using a clearance mechanism to ensure a thread path follows the contour of the rotation as the closure is removed from the mold.

17. The process of claim 16, wherein using the clearance mechanism includes providing clearance along the threads to enable smooth removal of the closure from the mold.

18. The process of claim 16, wherein using the clearance mechanism includes allowing for vents or other interruptions in the closure.

19. The process of claim 1, wherein lifting the closure includes using a timing mechanism to lift the closure at an axial rate that prevents deformation and unwanted height variation of the closure.

20. The process of claim 19, wherein using the timing mechanism includes lifting the closure at an axial rate of 1-2 mm / s.