DEVICE AND METHOD FOR MANUFACTURING A CONTAINER FROM A PREFORM

Description

[0001] The invention relates to a device and a method for producing a container from a preform, which has an interior enclosed by a wall and accessible via a handling opening. The device comprises a forming machine, in particular a stretch blow molding machine, which is configured to heat the preform and form it into a container preform with an interior and a neck section connecting the interior to the handling opening. The forming machine also has a container preform output. Furthermore, at least one trimming unit with a container preform input is provided for cutting the neck section. Cutting the neck section creates a container with an opening formed in or on the neck section and connected to the interior.Generic devices and methods are described in patents US2023 / 150183A1, US2020 / 171730A1, US2021 / 245416A1, US2003 / 211256A1 and US2006 / 121222A1.

[0002] Custom-designed devices and methods are employed when the container opening intended for later use is unsuitable or difficult to adapt to the manufacturing process. For example, particularly large and / or non-round container openings can only be formed with considerable effort in conventional stretch blow molding machines. Similarly, handling in additional processing equipment, such as coating lines, is only possible with significant effort.

[0003] For this purpose, manufacturing processes and equipment were developed in which a container pre-stage is first produced as an intermediate product and, if necessary, coated or labeled. These prepared container pre-stages are collected and later transformed into the final containers by cutting through or at the neck section – in a so-called trimming process – creating a container opening with the desired geometric properties – shape and dimensions. The trimming process is usually carried out using mechanical blades as cutting tools. However, this process is slow compared to container forming and places considerable stress on the cutting tools. High process speeds also lead to significant wear on the cutting tools.This is especially true if the containers are designed as so-called "hotfill" containers, which have a highly crystalline material structure due to a high processing temperature.

[0004] Against this background, the invention is based on the objective of increasing the processing speed of the trimming process and simultaneously extending the service life of the trimming units, in particular the cutting tools used therein. The subject matter of the invention and the solution to this objective is a device according to claim 1 and a method according to claim 7. Preferred embodiments are specified in the dependent claims.

[0005] Based on the generic device, the trimming unit is arranged according to the invention such that the container preform can be transferred to the container preform input of the trimming unit in a heated state, in particular at a temperature of at least 35 °C, preferably at least 50 °C. The solution according to the invention thus consists of carrying out the trimming process in the heated state of the container preforms. A corresponding arrangement of the trimming units within the device ensures that the container preform cannot acclimate to the ambient temperature – typically around 20 °C to 30 °C – but is transferred to the trimming unit with residual heat (e.g., from the forming process). Due to the increased temperature of the container preform, cutting the neck section is facilitated – even and especially with crystalline hot-fill containers.As a result, there is less wear on the trimming unit, especially on the cutting tools used there, leading to a longer service life and a cleaner cut at the container opening. Furthermore, the throughput of the trimming units can be increased compared to conventional systems without significantly increasing wear.

[0006] Preferably, the trimming unit has at least one cutting tool for cutting through the container pre-stage. These are preferably mechanical cutting tools, in particular blades. Due to the lower mechanical resistance of a heated container pre-stage, these are subject to less wear.

[0007] According to a preferred embodiment, the device has a coating system with a coating input and a coating output for coating, in particular for plasma coating of container precursors and / or containers.In For the coating process, uncoated container precursors or containers can be used and coated within the coating system. This coating can be, in particular, a silicon oxide coating produced by a plasma deposition process (a so-called plasma coating). The coating gives the container precursors or containers enhanced barrier properties, especially against gas and substance diffusion with carbon dioxide, water vapor, and / or oxygen.

[0008] The coating system is preferably positioned between the forming machine and the trimming unit. This allows the company to take advantage of the fact that a coating process, especially a plasma coating process, has a higher optimal temperature range than the trimming process. At the same time, the energy input during the coating process ensures that the pre-formed container is still sufficiently heated before being transferred to the trimming units.

[0009] Preferably, no heating device acting on the container pre-stage or the container is arranged between a container treatment machine – in particular a forming machine or coating system – and a trimming unit that follows without a further container treatment machine. The residual heat from the container process can be used particularly preferably in this case. In particular, no (active) temperature control device is provided in this area at all.

[0010] It is particularly preferred that the coating system and the trimming unit are directly connected or interlocked. This is the case when the coating output is connected directly to the pre-tray input of the trimming unit, or via no more than three handling units, especially star conveyors. Such a direct transfer prevents an excessive temperature drop before the trimming process. At the same time, the use of handling units—i.e., transport systems that move the pre-trays individually in discrete positions—ensures a clearly calculable influence on the temperature. This contrasts with other transport devices such as pneumatic conveying systems or conveyor belts.

[0011] Alternatively or additionally, at least one trimming unit can be arranged between the forming machine and the coating system. The residual heat from the forming process, particularly stretch blow molding, also contributes to the advantages of an improved trimming process according to the invention.

[0012] Similarly, a trimming unit can be integrated with the stretch blow molding machine. In this case, the container pre-stage output of the stretch blow molding machine is connected directly or via no more than three handling units, preferably transport stars, to the container pre-stage input of the trimming unit.

[0013] Within the scope of the invention, it is also conceivable that more than one trimming unit is provided in the same device. A plurality of trimming units enables an increase in throughput. This is particularly advantageous because—despite the improvement according to the invention—the process speed of trimming units is typically lower than the maximum achievable speed of forming machines such as stretch blow molding machines and, optionally, coating systems. The multiple trimming units can, in particular, be arranged directly downstream of the forming machine and are especially preferably connected to several container pre-stage outputs. Without limiting the invention, multiple trimming units can also be provided upstream and / or downstream of any coating system.

[0014] The invention also relates to a method for manufacturing a container from a preform, which has an interior enclosed by a wall and accessible via a handling opening. The preform is heated in a forming machine, preferably a stretch blow molding machine, and formed into a container preform with an interior and a neck section connecting the interior to the handling opening. Subsequently, the container preform is cut – in a so-called trimming process – by a trimming unit in or on the neck section, resulting in a container with an opening formed in or on the neck section and connected to the interior. According to the invention, the neck section is cut while heated – particularly relative to ambient temperature.In the course of the invention, it was found that the trimming process is easier to carry out on a heated container pre-stage - especially if it is a so-called hot-fill container.

[0015] According to a preferred embodiment, the neck section is cut at a trimming temperature of at least 35 °C, preferably at least 50 °C, particularly preferably at least 60 °C, and especially between 60 °C and 120 °C. Within this preferred temperature range, the cutting of the container preform – particularly by mechanical means – is facilitated, and the wear of the cutting tools is reduced.

[0016] Without limiting the invention, the trimming process can also be implemented in a way other than by a mechanical cutting process. For example, a thermal cutting process, in particular a laser cutting process, can also be used. Due to the already heated container, less thermal energy, in particular a lower beam energy from the cutting laser, is then required.

[0017] According to a particularly preferred embodiment, the container pre-stage is transferred from the forming machine directly or via no more than three handling units, preferably transfer stars, to the trimming units for cutting the neck section. The direct transfer—i.e., the interlocking between the stretch blow molding process and the trimming process—enables efficient use of the residual heat from the stretch blow molding. This eliminates the need for separate reheating of the container pre-stage.

[0018] Preferably, the container is coated, in particular with a plasma coating, after being cut. The heat loss due to the trimming process is minimal, so the resulting container remains within a preferred temperature range for the coating. This also prevents the residue remaining from the container precursor (compared to the container itself) from being contaminated by the coating process. Thus, the recyclability of this residue, free of contaminants and containing only a small amount of material, is ensured.

[0019] In an alternative embodiment of the inventive method, the container preform is provided with a coating, preferably a plasma coating, after forming and before cutting. This takes advantage of the fact that the container preform still retains sufficient residual heat after plasma coating to facilitate the simplified trimming process according to the invention. The use of a plasma coating process has the additional advantage that, due to the additional energy input, it results in less heat loss during the coating process or even generates additional heating – particularly with a temperature input of approximately 20 K to 40 K. Plasma coatings are also applied in such a minimal layer thickness that the recycling of the offcuts (residue) is not significantly hindered.

[0020] Preferably, the container pre-stage after plasma coating has a temperature of at least 45 °C, and particularly at least 60 °C. In particular, it operates within a temperature range between 60 °C and 120 °C. This range guarantees sufficient mechanical stability of the container pre-stage for cutting, while simultaneously significantly improving the cutting process compared to room temperature.

[0021] Preferably, the container pre-stage is transferred directly to the trimming unit after coating, or with no more than three handling units, preferably transport stars. In this case, the coating system is integrated with the trimming unit. This enables a clearly defined and predictable temperature profile between the coating system and the trimming unit.

[0022] In a preferred embodiment, several trimming units are provided, wherein the container pre-stages are cut through in the several trimming units, preferably alternately. This allows the overall throughput of the process to be increased.

[0023] Preferably, the remaining portion of the container preform after cutting – the so-called dome – is subsequently recycled. This dome consists of the same polymer material as the rest of the preform and is therefore particularly well-suited for single-material recycling.

[0024] The invention relates in particular to preforms made of a polymer material, especially polyethylene terephthalate (PET).

[0025] The remaining material is preferably melted down and reused to produce preforms. This single-stream recycling allows for optimal utilization of the available polymer material.

[0026] The preform is particularly well-suited for forming at temperatures between 160 °C and 180 °C. Within this range, the preform material – especially the polymer PET – can be formed into a so-called hot-fill container with a high degree of crystallinity in the resulting container (or container precursor). This high crystallinity results in good mechanical and optical properties.

[0027] To ensure mechanical stability during the forming process, the preform is cooled on its inner surface during the transformation into the container preform. A drawing bar, inserted into the interior of the preform during the forming process, can be used for this purpose. The drawing bar can be actively cooled and / or cooled by a coolant flowing through it, or a coolant can be injected into the interior of the container.

[0028] It is particularly preferred that the container pre-stages and the cutting tools used in the trimming units are not heated. By utilizing residual heat within the forming process and, optionally, a subsequent coating, such active heating is unnecessary. This saves on the material costs for a heating device and the energy required for it.

[0029] According to a particularly preferred embodiment of the method, a leakage measurement of the container is carried out after the trimming process, i.e., after cutting. The container opening is sealed, and an overpressure or underpressure is applied to the interior of the container. A leak—particularly one caused by imperfect cut surfaces at the container opening—can be detected by monitoring the change in this pressure differential over time. The leakage measurement is particularly preferably carried out immediately after the trimming process. A so-called leakage carousel is used for this purpose.

[0030] The invention is explained below with reference to figures illustrating only exemplary embodiments. These figures schematically show: Fig. 1A a schematic side view of a preform, Fig. 1B a schematic representation of a container pre-stage, Fig. 1C a schematic representation of a container produced according to the inventive method and Fig. 2A a schematic top view of a device according to the invention in a first embodiment and Fig. 2B one of the Fig. 2A corresponding view in a second embodiment.

[0031] The invention relates to a device 1, 1' for producing containers 2 from preforms 3, as described in the Fig. 1A The preforms 3 have an interior 3b enclosed by a wall 3a, which is accessible through a handling opening 3c. The handling opening 3c is formed with a profiled edge 3d, on which the preforms 3 or subsequently produced container preforms 4 can be guided with gripping tools of the device 1.

[0032] The in the Figuren 2A and 2BThe devices 1, 1' shown according to the invention each have a forming machine 5, which in these embodiments is designed as a stretch blow molding machine. The forming machine 5 is configured to take the preforms 3 from a preform feeder 6 and heat them to a forming temperature in a heating tunnel 5a with heating elements 5b. The heated preforms 3 are then blown into a form in blowing stations of a blow wheel 5c. Fig. 1B The container pre-stage 4 shown is transformed.

[0033] The container preform 4 has an interior space 4a and a neck section 4b connecting the interior space 4a with the handling opening 3c (including the profiled edge 3d) taken from the preform 3. Furthermore, a container preform output 5d is designed in the form of a transfer star, with which the formed container preforms 4 can be discharged from the forming machine 5. The container preform output 5d is at least partially arranged in an enclosure 5e of the forming machine 5.

[0034] In the Fig. 2A In the illustrated embodiment, the container pre-stages 4 are taken over and forwarded by a transfer device 7, which has a plurality of interconnected transfer stars 7a. Furthermore, the device 1, 1' comprises at least one trimming unit 8, 8' with at least one container pre-stage input 8a, 8a' and a cutting device 8b, 8b' for cutting through the neck section 4b.

[0035] The result of this trimming process is in the Fig. 1C As shown, a container 2 is formed, which takes over the interior space 4a of the container pre-stage 4. This is accessible through a container opening 2a, which is bordered by a cut surface of the trimming process. A residue 9 remains from the original container pre-stage 4, which includes the original handling opening 3c with the profiled edge. This residue 9 is discharged from the trimming unit 8, 8' and sent for recycling.

[0036] According to the invention, the trimming unit 8, 8' in both embodiments is as described below. Fig. 2A and 2B arranged such that the container pre-stages 4 are transferred to the container pre-stage input 8a, 8a' of the trimming unit 8, 8' in a heated state, in particular at a temperature of at least 35 °C.

[0037] In according to the first embodiment shown Fig. 2A The device 1 comprises a coating system 10 in the form of a plasma coating system. The coating system 10 includes a coating inlet 10a for receiving the container preforms 4 from the transfer unit 7, a first reversing wheel 10b to reverse the container preforms from an upward-opening orientation to a downward-opening orientation. The container preforms 4 are then transferred via a first grouping station 10c to a coating wheel 10d. There, groups of several, in particular four, container preforms 4 are coated with a silicon dioxide plasma coating in rotating coating stations. After completion of the coating process, the now-coated container preforms 4 are transferred from the coating wheel 10d by a second grouping station 10e and fed to a second reversing wheel 10f. There, they are returned to their original upward-opening orientation.The coated container pre-stages 4 are transferred via an output wheel 10g of the coating system 10 to the container pre-stage input 8a of the trimming unit 8. This means that the coating system 10 and the trimming unit 8 are directly connected to each other – i.e., interlocked.

[0038] In the Fig. 2B The reverse arrangement consists of a trimming unit 8' directly connected to the forming machine 5 and a coating unit 10' directly connected to the container discharge of the trimming units 8'. This coating unit has a structure corresponding to the coating unit 10 of the first embodiment. Corresponding reference numerals are each preceded by an apostrophe ('). Reference symbol list

[0039] 1,1'Device 2Container 2aContainer opening 3Preform 3aWall 3bInterior 3cHandling opening 3dProfiled edge 4Container preform 4aContainer interior 4bNeck section 5Forming machine 5aHeating tunnel 5bHeating device 5cForming wheel 5dOutput wheel 5eEnclosure 6Preform feeder 7Transport device 7aTransport star 8, 8'Trimming unit 8aContainer preform feeder 8b, 8b'Cutting tool 9Remainder 10, 10'Coating system 10a, 10a'Coating feeder 10b, 10b'First turning wheel 10c, 10c'First grouping station 10d, 10d'Coating wheel 10e, 10e'Second grouping station 10f, 10f'second turning wheel 10g, 10g'coating issue

Claims

1. A device (1, 1') for manufacturing a container (2) from a preform (3) which comprises an interior space (3b) enclosed by a wall (3a) and accessible via a handling opening (3c), - with a forming machine (5), which is configured to heat the preform (3) and to form it into a container precursor (4) with a container interior space (4a) and a neck section (4b) connecting the container interior space (4a) with the handling opening (3c) and comprises a container precursor output (5d), - and with at least one trimming unit (8, 8') comprising a container precursor input (8a, 8a') for cutting through the neck section (4b) so that a container (2) with a container opening (2a) formed in or on the neck section (4b) and connected to the container interior space (4a) is formed, characterized in that the trimming unit (8) is arranged in such a way that the container precursor (4) in the heated state, at a temperature of at least 35°C, can be transferred to the container precursor input (8a, 8a') of the trimming unit (8, 8').

2. The device (1, 1') according to the preceding claim, characterized by a coating system (10, 10') with a coating input (10a, 10a') and a coating output (10g, 10g') for coating, in particular, plasma coating, of container precursors (4) and / or containers (2).

3. The device (1) according to the preceding claim, characterized in that the coating system (10) is arranged between the forming machine (5) and the trimming unit (8).

4. The device (1) according to the preceding claim, characterized in that the coating output (10g) is connected directly or with no more than three handling units, preferably transport stars, to the container precursor input (8a) of the trimming unit (8)5. The device (1') according to any one of the preceding Claims 2 or 3, characterized in that at least one trimming unit (8') is arranged between the forming machine (5) and the coating system (10').

6. The device (1, 1') according to any one of the preceding claims, characterized in that the container precursor output (5d) of the forming machine (5) is connected directly or with no more than three handling units, preferably transport stars, to the container precursor input (8a, 8a').

7. A method for manufacturing a container (2) from a preform (3) which comprises an interior space (3b) enclosed by a wall (3a) and accessible via a handling opening (3c), wherein the preform (3) is heated in a forming machine (5) and formed into a container precursor (4) with a container interior space (4a) and a neck section (4b) connecting the container interior space (4a) with the handling opening (3c), and wherein the container precursor (4) is subsequently cut by a trimming unit (8, 8') in the neck section (4b) so that a container (2) is formed with a container opening (2a) formed in or on the neck section (4b) and connected to the container interior space (4a), characterized in that the neck section (4b) is cut in the heated state at a trimming temperature of at least 35°C.

8. The method according to the preceding claim, characterized in that the neck section (4b) is cut at a trimming temperature of at least 35°C, preferably at least 60°C, in particular, between 60°C and 120°C.

9. The method according to any one of the preceding Claims 7 or 8, characterized in that the container precursor (4) is transferred from the forming machine (5) to the trimming unit (8') directly or via no more than three handling units, preferably transfer stars.

10. The method according to any one of the preceding Claims 7 to 9, characterized in that the container (2) is provided with a coating, in particular, a plasma coating, after cutting.

11. The method according to any one of the preceding Claims 7 to 9, characterized in that the container precursor (4) is provided with a coating, preferably a plasma coating, after forming and before cutting.

12. The method according to the preceding claim, characterized in that the container precursor (4) comprises a temperature of at least 45°C, in particular, at least 60°C after coating, in particular, plasma coating.

13. The method according to any one of the preceding Claims 11 or 12, characterized in that the container precursor (4) is transferred to the trimming unit (8) immediately after coating or with not more than three handling units, preferably transport stars.

14. The method according to any one of the preceding Claims 7 to 13, characterized in that a plurality of trimming units (8, 8') are provided and the container precursors (4) are cut in the plurality of trimming units (8, 8'), preferably alternatingly.

15. The method according to any one of the preceding Claims 7 to 14, characterized in that the remainder (9) of the container precursor (4) remaining after cutting from the container (2) is subsequently fed to be recycled.

16. the method according to the preceding claim, characterized in that the remainder (9) is melted down and used for manufacturing preforms (3).

17. The method according to any one of the preceding Claims 7 to 16, characterized in that the preform (3) is formed at a temperature between 160°C and 180°C.

18. The method according to any one of the preceding Claims 7 to 17, characterized in that the preform (3) is cooled on an inner side during forming to the container precursor (4), in particular, cooled by the supply of cooling medium through a hollow stretching bar.

19. The method according to any one of the preceding Claims 7 to 18, characterized in that the container precursor (4) and the cutting tools (8a, 8a') used in the trimming units (8, 8') are not heated.

20. The method according to any one of the preceding claims 7 to 19, characterized in that after cutting, in particular, immediately afterwards, a leakage measurement of the containers (2) is carried out.