DE102024001610A1 - Device and method - Google Patents

Abstract

2. Device for producing a preform, in particular in the form of a melt tube, comprising at least an extruder (10) which can be loaded on a feed side (19) with a plastic material, in particular in granular form, and which provides a flowable plastic medium, in particular in plasticized form, on the output side, which enters the inlet side (30) of a tube head (26), which provides the preform on its discharge side (32), characterized in that at least one intermediate piece (44) is connected in a connection between the discharge side (24) of the extruder (10) and the inlet side (30) of the tube head (26) by means of individual coupling points (31), which has a treatment zone (38) which is not originally attributable to either the extruder (16) or the tube head (26) and forms an additional volume (Z) which leads to an increase in the residence time of the plastic medium in the device and that, at least during operation of the device at least one device (40) is present that reduces the microbial load on the plastic material within the treatment zone (28).

Description

The invention relates to a device for producing a preform, in particular in the form of a melt tube, comprising at least an extruder which can be loaded on a feed side with a plastic material, in particular in granular form, and which provides a flowable plastic medium, in particular in plasticized form, on the output side. This medium enters a tube head, which provides the preform on its discharge side. The invention further relates to a method, in particular using such a device.

Through EP 1 086 019 B1 A method and apparatus for producing sterile packaging containers are known. The thermoplastic container is heated to a temperature below the deformation temperature of the thermoplastic material. However, this temperature is higher than the temperature of the gas phase of a sterilizing material. Finally, the sterilizing material is removed with hot air, and then the final shape of the plastic container is blown with sterile air. The known method also uses a suitable chemical for sterilization.

• - dass jeweils ein erwärmter Vorformling in jeweils einen mehrteiligen Formenträger der Blasmaschine zur Herstellung von Kunststoffbehältern eingesetzt wird, wobei jeder Formenträger eine mehrteilige Blasform trägt; und
• - dass mindestens ein Teil der Blasform mit einer Zuführung für ein Medium verbunden wird, damit das Medium über eine Blasdüse während des Blasvorganges in das Innere des Vorformling des jeweiligen Kunststoffbehälters, der Vorblaslinge oder des Kunststoffbehälters mit einer Temperatur zwischen 80°C bis 140°C geleitet wird.

Through DE 10 2008 032 635 A1 A process for the microbiologically optimized production of plastic containers, including an associated blow molding machine, is known, comprising the following process steps:

• - that each heated preform is inserted into each multi-part mold carrier of the blow molding machine for the production of plastic containers, each mold carrier holding a multi-part blow mold; and
• - that at least one part of the blow mold is connected to a feed for a medium so that the medium is directed via a blow nozzle into the interior of the preform of the respective plastic container, the pre-blows or the plastic container at a temperature between 80°C and 140°C during the blowing process.

In this way, without the use of chemical agents, recontamination of previously sterilized preforms by the blow molding process itself is prevented, thus ensuring that contamination in the blow molding machine itself is avoided.

A comparable method and apparatus is described by DE 10 2011 008 132 A1 Known processes exist in which a preform made of a thermoplastic material is first heated and then stretched by a stretching bar and subjected to a pressurized fluid, wherein the stretching bar is sterilized at least partially and at least temporarily in the area of a blowing device. Sterilizing the stretching bar in the area of the blowing device makes it possible to avoid labor-intensive assembly and disassembly processes that would otherwise be required for external sterilization of the stretching bar.

• - einer energiereichen Strahlung und/oder
• - einer Plasmabehandlung und/oder
• - einem sterilisierend wirkenden Gas, wobei der jeweilige genannte Behandlungsschritt erfolgt,
• - wenn das Kunststoffgranulat noch zu sackartigen Gebinden zusammengefasst ist, nach deren Öffnen die Zuführung des Granulats in die Extrudereinrichtung im Rahmen der ersten Herstellkette erfolgt, oder
• - wenn das Kunststoffgranulat im Rahmen einer Vereinzelung innerhalb der ersten Herstellkette im Rahmen einer flächigen schütt- oder trichterartigen Zuführung der Schnecke der Extrudereinrichtung zugeführt wird.

Furthermore, through EP 3 356 115 B1 A method for reducing the microbiological contamination of container products is known, which consist at least partially of at least one plastic material, in which, as part of a first manufacturing chain, plastic granules are fed to an extruder which melts the granules, which, as part of a further subsequent manufacturing chain, are transferred to a blow molding, filling and sealing machine to obtain the respective container product, wherein, at least in parts of the first manufacturing chain, the plastic granules used are subjected to at least one of the following treatment steps:

• - high-energy radiation and/or
• - a plasma treatment and/or
• - a sterilizing gas, whereby the respective treatment step mentioned takes place,
• - if the plastic granules are still bundled into bag-like packages, after which the granules are fed into the extruder unit as part of the first production chain, or
• - when the plastic granules are fed into the extruder screw as part of a singulation process within the first production chain using a flat, pouring or funnel-like feed.

In this way, a significant reduction of microbiological contaminants within the plastic granules, especially on their surface, can be achieved with relatively little technical effort. before the plastic granules enter the extruder unit and subsequently the attached hose head for the purpose of forming a hose-like preform.

Based on this prior art, the invention aims to further improve the known solutions in such a way that a reliable reduction of microbiological contamination of container products, which are manufactured in particular by a form, fill and seal process, is achieved in a simple, robust and continuous manner without the use of chemicals or high-energy radiation.

A device with the features of claim 1 in its entirety and a method with the features of claim 9 solves such a problem.

According to the characterizing part of claim 1, at least one intermediate piece is inserted into a connection between the discharge side of the extruder and the inlet side of the die head by means of individual coupling points. This intermediate piece comprises a treatment zone that is not inherently attributable to either the extruder or the die head and forms an additional volume that increases the residence time of the plastic medium in the device. Furthermore, at least during operation of the device, at least one device is present that reduces the microbial load on the plastic material within the treatment zone. This makes it possible to select a temperature in the treatment zone significantly higher than the usual recommended processing temperatures for blow molding of hollow body products. Surprisingly, such elevated temperatures, which significantly reduce the microbial count, are possible in the treatment zone without causing noticeable damage or significant degradation of the plastic material, as is otherwise expected in the prior art. The treatment zone, or rather the additional volume, can be retrofitted to existing devices without significant effort. It is particularly desirable that the flow through the additional volume be unobstructed.

In a preferred embodiment of the device according to the invention, the respective coupling point is formed by a flange connection. Preferably, each flange connection has flanges arranged in pairs, each of which forms part of a tubular connecting piece between the extruder, hose head, and intermediate piece. These flanges are held together, for example, by a screw connection and/or can be secured to one another by means of a clamp, particularly in the form of a clamping connector. Flange connections are widely used in industry and regularly allow a leak-free connection between fluid-carrying components, such as pipe sections. Flange connections can be largely standardized and implemented cost-effectively, and in the present case, they allow for the selective insertion and replacement of intermediate pieces with treatment zones between the extruder outlet and the hose head inlet within the framework of so-called BFS technology.

In a preferred embodiment of the device according to the invention, the treatment zone comprises a reactor located in functional areas between the outlet side of the extruder and the inlet side of the die head. Preferably, the reactor optionally comprises, as individual components of the treatment zone, at least one container chamber with an increased volume relative to an adjacent inlet and outlet side for the plastic material, and optionally a mixer, and/or a stirrer, and/or a homogenizer.

In a particularly preferred embodiment of the device according to the invention, the container chamber is widened in diameter compared to the tubular connecting pieces to achieve an increased volume, and/or, preferably with the same pipe diameter, is extended to a predetermined installation length, which can also be achieved by means of an arc. The desired increase in volume for the container chamber, optionally through diameter widening and/or extension, allows for a variety of space-saving possibilities, depending on the specified installation modalities, to increase the residence time of the plastic medium in the device with differently configured additional volumes.

The reactor or treatment chamber volume is preferably selected based on the type of plastic material, its processing temperature, and the mass flow rate of the plastic material through the tube head. In particular, the temperature setting during operation or production is chosen such that the highest temperature prevails in the additional volume, which can be achieved in a structurally simple manner by means of an additional heater for the treatment chamber. The outlet temperature at In contrast, the nozzle of the hose head can then be set lower - for example by reducing the heating power at/in the hose head - which, due to the increased viscosity of the plastic, can simplify the container shaping and reduce the heat load on the container contents.

The optional use of at least one mixer, one stirrer, and/or one homogenizer allows for further temperature homogenization, resulting in very small temperature differences within the reactor or treatment chamber. Preferably, at least two individual reactor components can be connected in parallel or in series with respect to the fluid flow of the plastic material.

In a further preferred embodiment of the device according to the invention, the treatment zone and/or the hose head is provided with one or, preferably, several sensors, in particular for measuring and/or controlling the temperature of the plastic material. The corresponding sensor data can be recorded and transmitted to a central process control system, which also regulates the different heating zones depending on the mass throughput of the plastic.

Various sensor types can be used to measure the temperature in molten plastic (also known as melt temperature), such as IR thermometers or ultrasonic thermometers. Pt-100 resistance thermometers according to DIN EN 60751, available, for example, from Juno, Fulda, Germany, or thermocouples according to DIN EN 60584 Class 1, such as the Matex 10 available from Tematec, 53759 Hennef, Germany, are preferred. Thermocouples with a sword-shaped tip are preferred because this minimizes the alteration of the plastic flow.

Multiple thermocouples distributed throughout the treatment volume and the hose head are particularly preferred.

For pressure measurement in molten plastic (also known as mass pressure), so-called melt pressure transducers are used, preferably mercury-free pressure sensors with corrosion-resistant metal diaphragms, for example Vertex ^® sensors from Dynisco Europe GmbH, 74078 Heilbronn, Germany.

In a further preferred embodiment of the device according to the invention, the respective device for reducing microbial load has an energy output device that is arranged inside and/or outside the treatment chamber and is preferably a heat output source. In addition to an auxiliary heater on the outside of the reactor or treatment chamber, it is also possible to provide heating elements directly inside the additional volume, for example, at least one heating element that can be heated inductively or electrically.

In a further preferred embodiment of the device according to the invention, the additional free volume Z of the treatment zone, through which the fluid flow containing the plastic material flows, is at least 50 ^cm³ , preferably at least 100 ^cm³ . It is further preferred that the ratio of the free volume Z of the treatment zone to the free volume V along the path, measured from the tip of an extruder screw of the extruder to the nozzle outlet for the preform at the die head, is at least 0.05, preferably at least 0.10. The additional volume Z is preferably also selected depending on the average plastic throughput (mass throughput per unit of time in kg/h) through the device. Preferably, the average residence time of the plastic between the tip of the extruder screw and the nozzle outlet should be increased by at least 10%, preferably by at least 30%, due to the additional volume, compared to the average residence time between the tip of the extruder screw and the nozzle outlet, without including the reactor or treatment chamber according to the invention.

In a method according to the invention, incorporating the device described above, the average residence time of the plasticized or molten plastic material in the additional volume Z, formed by the reactor or treatment chamber, is preferably in the range of 5 to 50 seconds.

Further advantageous embodiments of the method according to the invention are the subject of the other dependent claims.

• 1 in der Art einer Längsschnittdarstellung eine erfindungsgemäße Vorrichtung, bestehend aus einem Extruder und einem Schlauchkopf (beide nur teilweise dargestellt) und einer dazwischen geschalteten Reaktor- oder Behälterkammer nebst in Fluidströmungsrichtung gesehen vorgeschalteter Behandlungsstufe;
• 2 und 3 jeweils gegenüber der 1 geänderte Ausführungsbeispiele; und
• 4 in perspektivischer Draufsicht eine Schelle respektive einen Klemmverbinder zum Festlegen einzelner Flanschverbindungen aneinander zwecks Anbringen eines jeweiligen Verbindungs- oder Zwischenstückes zwischen Extruder und Schlauchkopf.

The device according to the invention, along with the associated method, will now be explained in more detail using exemplary embodiments as shown in the drawing. The drawings are presented in a general, not to-scale, representation of the device.

• 1 in the manner of a longitudinal section view a device according to the invention, consisting of an extruder and a hose head (both only partially shown) and an intermediate reactor or container chamber together with a treatment stage upstream in the direction of fluid flow;
• 2 and 3 each opposite 1 modified embodiments; and
• 4 In a perspective top view, a clamp or a clamping connector for fixing individual flange connections to each other in order to attach a respective connecting or intermediate piece between extruder and hose head.

The 1 Figure 1 shows a simplified longitudinal section of a device for producing a preform, particularly in the form of a melt tube (not shown). The device includes an extruder 10 in the form of a screw extruder, whose feed screw 12 can be driven by a drive 14. The feed screw 12 is guided in a tubular extruder housing 16, which is provided on its outer circumference with individual sleeve-shaped heating elements 18, for example, in the form of an electric resistance heater. On the top side of the extruder housing 16, adjacent to the drive 14, a feed hopper 20 or other feeding device is provided on the feed side 19 of the extruder 10, by means of which plastic granules (not shown) can be fed in order to plasticize or melt them by means of the extruder 10. The extruder 10 has an annular discharge side 24 with a predefinable free diameter in the area of its screw tip 22 and thus on the outlet side.

Furthermore, the device has a hose head 26, which is in 1 The diagram is only highly schematic. The tube head 26 has a cylindrical feed section 28, which, like the extruder housing 16, carries a mat-shaped heating element 18 on its outer circumference. The free cross-section of the feed section 28 forms an inlet side 30 for the tube head 26, which is provided with a nozzle outlet 34 on its discharge side 32. This nozzle outlet serves to discharge a plastic tube as a melt tube to a manufacturing machine (not shown), for example, a forming, filling, and sealing machine for producing formed, filled, and closed or sealed container products, including bottles and/or ampoules. Such machines are used, for example, in DE 10 2020 004 564 A1 , DE 10 2008 006 073 A1 and EP 3 356 115 B1 and especially in DE 10 2020 002 077 A1 described in detail. The manufacturing process is also known in technical terms as the blow-fill-seal process or BFS process for short. The hose head 26 has an internal guide section 36 that receives the plasticized plastic material from the feed section 28 and directs it towards the 1 The fluid is transported vertically downwards towards the nozzle outlet 34. For improved fluid flow from the inlet side 30 of the tube head 26 to its outlet side 32, the tube head is again equipped with mat-shaped heating elements 18 along its outer circumference. This combination of extruder 10 with tube head 26 is common and exemplified in EP 3 356 115 B1 This has been demonstrated, so that it will not be discussed in more detail here.

As can be further seen from the 1 As a result, a treatment zone 38 is integrated along a path X between the discharge side 24 of the extruder 10 and the inlet side 30 of the die head 26 in the form of the feed section 28. This treatment zone 38 is not inherently part of either the extruder 10 or the die head 26. Along path X, this treatment zone 38 features a change in shape in the form of an additional volume Z, which increases the residence time of the plastic medium within the device. Furthermore, at least during operation, a device 40 is provided to reduce the microbial load on the plastic material within the treatment zone 38. The treatment zone 38 includes a reactor 42, designed as an intermediate piece 44, which is arranged in functional areas between the outlet or discharge side 24 of the extruder 10 and the inlet side 30 of the die head 26. Accordingly, the reactor 42 is inserted along parallel interfaces 46 between the extruder 10 and the tube head 26, the interfaces 46 being fictitiously extended for clarity and enclosing the predefinable path X between them. The respective intermediate piece 44 then has the same free passage cross-section along its two opposing interfaces 46 as the discharge side 24 of the extruder 10 and the inlet side 30 of the tube head 26 with the feed section 28.

The reactor 42 has a container chamber 48 with an increased volume, or additional volume Z. In this case, the container chamber 48 also has an increased installation length Y in the form of a tubular connecting piece 50, which is part of a further intermediate piece 44. In the installed state, the container chamber 48 abuts the feed section 28 with its free end face, and the free end of the connecting piece 50, or of the further intermediate piece 44, opens into the discharge side 24 of the extruder 10. In this respect, the reactor 42 as a whole is connected to the respective adjacent inlet and outlet sides for the plastic material. In addition to the container chamber 38 as one of the individual components of the reactor 42, it also has a mixer 52 as another individual component. This mixer is located in the connecting piece 50 and is primarily responsible for homogenizing the fluid flow from the extruder 10 with the plastic material. Instead of the mixer 52, other individual components, such as a stirrer or a homogenizer (all not shown), can be used as alternatives or additions with comparable function. In this case, however, the reactor 42 consists of the two individual components 48 and 52, which are connected in series as intermediate pieces 44 with respect to the fluid flow of the plastic material. Furthermore, the treatment zone 38, or the reactor 42, can be equipped with sensors (not shown) on its inner and/or outer circumference, in particular for measuring and/or controlling the temperature of the plastic material. In addition to temperature measurement, sensors can also be used to determine the fluid pressure, fluid density, and viscosity. All achievable sensor data can be forwarded to a process control system (not shown), which controls, in particular, the extruder 10 to regulate individual heating devices 18 and thus the local temperatures of the plastic material as well as its throughput.

The respective device 40 for reducing microbial contamination is provided with an energy emission device 54, which in the present case is arranged outside the treatment chamber 38 and is preferably designed as a heat emission source, for example again in the form of a cuff-like separately controllable heating device 18. This is also present on the outer circumference at the connection nozzle 50.

The two intermediate pieces 44, in the form of the individual components 48 and 50, are connected to each other by means of coupling points 31 in the form of flange connections 33. Likewise, the container chamber 48 is connected to the feed section 28 of the hose head 26, and the connection nozzle 50 is connected to the annular discharge side 24 of the extruder housing 16. Preferably, all flange connections 33 are identical; in particular, all flanges 35 of the flange connections 33 are of the same size. Each flange 35 typically has a right-angled projecting contact surface which, together with an adjacent contact surface of another flange 35, forms the respective flange connection 33 as soon as the paired flanges 35 are connected to each other in a releasable manner by means of a space-saving fastening element, such as a screw connection (not shown). To prevent leakage losses, a sealant 5 is typically applied between the adjacent flanges 35. 4 ), such as a sealing ring or the like, inserted.

The flange connection 33 serves to connect two components, usually in the form of pipes or tubular connecting bodies, such as those formed by components 24, 28, 48 and 50, which abut each other flush, with a clamp, such as a clamping connector 41, now used instead of a screw connection for their connection. When using such a clamping connector 41, as shown by way of example in the 4 shown, and in more detail DE 10 2008 026 563A1 As described by the patent holder, it is advantageous if the respective flange 35 has an inclined external clamping surface for interaction with the clamping connector 41, which faces away from a clamping surface of the other flange 35 of a connection pair.

The clamping connector 41 after the 4 This then serves to clamp individual flanges 35 together with the tubular bodies, which may be welded to their ends or be an integral part thereof. An annular sealing element 5 is inserted between the two flanges 35, forming the flange connection 33. For the sake of simplicity, this sealing element is shown in the 1 , 2 and 3 The clamping connector 41 itself has two clamping ring parts 1, 3, which are connected at one end via a hinge arrangement 11 and can pivot about this arrangement between spread positions and clamped positions approaching each other. At one end of the clamping ring parts 1, 3 opposite the hinge arrangement 11, the clamping connector 41 has a clamping device with a clamping screw 15, which can be adjusted from an operating position as shown in the illustration. 1 in which it interacts with the clamping ring parts 1, 3 to generate a clamping force that forces them into the clamping positions, and is pivotable into a release position folded away from them, in which the clamping ring parts 1, 3 release the flange connection The clamping device further comprises a locking device 25, 27 which, in its active state, prevents the clamping screw 15 from unintentionally folding down into the release position and, depending on the spreading of the clamping ring parts 1, 3 by a predetermined opening angle, transitions from the active state to a release state that allows the clamping screw 15 to fold down. For actuating the clamping screw 15, it is provided in the usual manner with a handle 31 and a coupling piece 33, which has at its end a widened flange as part 27 of the locking device for engaging a projection 25 on both sides of an engagement groove in the housing 6 of the clamping connector 41. A pivot axis 17 serves for pivoting the clamping screw 15 in and out of the aforementioned housing 6. 4 In the illustrated embodiment, the clamping connector 41 is attached to the tubular feed section 28 of the hose head 26 in order to establish the connection to the adjacent intermediate piece 44 with the treatment zone 38. The 4 The clamping connection shown is preferably intended for all coupling points 31 in the 1 , 2 and 3 They are used in such a way that no further reference will be made to them below.

The free additional volume Z of the treatment zone 38, through which the fluid flow containing the plastic material flows, is at least 50 ^cm³ , preferably at least 100 ^cm³ . The ratio of the free additional volume Z of the treatment zone 38 to the free volume V along a path measured from the screw tip 22 of the extruder or conveying screw 12 of the extruder 10 to the nozzle outlet 34 on the tube head 26 should be at least 0.05, preferably at least 0.10. According to the invention, the free additional volume Z, which can be filled with plastic melt and largely corresponds to the treatment chamber volume, is more than 50 ^cm³ , preferably in the range between 50 ^cm³ and 1000 ^cm³ , and particularly preferably in the range between 100 ^cm³ and 800 ^cm³ . Preferably, an additional volume Z greater than 100 ^cm³ is selected. For this purpose, the free additional volume Z in the container chamber 48 is designed in the manner of a rotational ellipsoid; in particular, the transitions of the chamber 48 are smoothed on both the inflow and outflow sides.

Preferably, the ratio Z/V of the treatment chamber volume Z to the volume V fillable with plastic melt between the tip 22 of the extruder screw 12 and the tube head 26 up to the nozzle outlet 34, without including the additional volume Z according to the invention, is at least 0.05; more preferably, the ratio Z/V is in the range of 0.08 to 0.4. The additional volume Z is therefore at least 5%, preferably 8 to 40%, of the volume V fillable with plastic from the tip 22 of an extruder screw of the extruder 10 to the nozzle outlet 34 for the preform at the tube head 26.

Preferably, in a process incorporating the apparatus as described above, the residence time of the molten or plasticized plastic material within the treatment zone 38 is at least 5 seconds, preferably at least 10 seconds, and particularly preferably at least 15 seconds. Preferably, the average temperature of the molten or plasticized plastic material in the treatment zone 38 is at least 170°C, preferably at least 180°C, and particularly preferably at least 185°C. For low-density polyethylene (LDPE) plastic materials, the average temperature in the treatment zone 38 can be at least 170°C, preferably at least 175°C, and particularly preferably at least 180°C. This is significantly higher than the recommendations for a 140°C melt temperature for blow molding according to the relevant technical literature, such as... Domininghaus: Plastics and their properties, 5th edition 1995, page 135 or Otto Schwarz in: Vogel Fachbuch, Kunststoffkunde, 4th edition 1992, page 66 .

In general, it can be said that the average temperature of the molten or plasticized plastic material in the treatment zone 38 is preferably at least 10°C, particularly preferably at least 15°C higher than the average temperature of the corresponding plastic material at the nozzle outlet 34 of the hose head 26.

The treatment chamber volume Z is preferably selected depending on the mass throughput of the plastic, as well as the type of plastic and its processing temperature. Tests have shown that at processing temperatures T above approximately 170°C, the following applies: the higher the processing temperature T, the smaller the treatment chamber volume Z can be for the same microbiological effect. Furthermore, it has proven advantageous to at least partially increase the cross-section of the feed channels (not shown) running within the die head 26 for the molten plastic material, from the extruder-side inlet to the point where the plastic enters the die gap or die outlet 34. Feed channels are typically used that branch out from a common inlet or junction into two branches. For larger die heads 26 with a typical throughput of approximately 50 to approximately 70 kg/h, the aforementioned diameter- or an increase in cross-sectional area from 2.5 cm to 3.5 cm, without taking into account the treatment or container chamber 48, almost doubles the volume of the feed channels. For smaller hose heads 26, however, with a typically lower throughput of approximately 15 kg/h to approximately 40 kg/h, an increase in diameter from 1.5 cm to 2.5 cm results in an increase in the feed channel volume by a factor of approximately 1.8. This also leads to an increase in the residence time of the plastic material within a treatment zone 38, supplemented here by the aforementioned feed channels.

The embodiment according to the 2 Figure 1 now shows an example of how to obtain a significantly increased additional volume Z. For this purpose, the treatment zone 38 is considerably lengthened by eliminating the connection nozzle 50 and by forming the container chamber 48 in the form of a loop 60. The loop or bend profile could be further extended if necessary, for example, by choosing a meander shape for the container chamber 48. Thanks to the container loop 60, the free path between the discharge side 24 of the extruder 10 and the inlet side 30 of the tube head 26 is significantly longer, thus also extending the residence time of the molten or plasticized plastic material in the loop 60. Two cylindrical heating sleeves 18, acting on the tube arms 62 of the loop 60 which are deflected by 180°, serve as an energy emission device 54, ensuring a substantial degree of germicidal action. This has no equivalent in the state of the art.

The further embodiment according to the 3 differs from the previous embodiments according to the 1 and 2 insofar as the additional volume Z is generated as an intermediate piece 44, which consists of an axial extension in the form of a pipe section 63, which in turn is connected at its ends by means of two flange connections 33 to the discharge side 24 of the extruder 10 and to the hollow cylindrical feed section 28 on the side of the hose head 26. Accordingly, the pipe section 63 has a substantially identical diameter at the connection points to the connecting pipe sections of the screw conveyor 12 and the hose head 26. The intermediate piece 44 is again comparable to the solution according to the 1 equipped with a mixer 52, which is arranged in the direction of the extruder 10 and opens into a free path length on its other side, with a predefinable axial length until reaching the flange connection 33 with the hose head 26.

Finally, the solution according to the invention will be explained in more detail using two application examples:

Examples 1-10:

A BFS system of type bottelpack 460 from the company rommelag, Waiblingen, Germany, was used, as exemplified in DE 10 2008 006 073 A1 and EP 3 356 115 B1 The process is described in detail, with a cycle time for container production of approximately 3.5 seconds. Eltex med PH27D630 from Ineos Polyolefins was used as the LDPE plastic material.

To prepare the contaminated granule samples, endospores of Bacillus atrophaeus ATTC 9372 with an average D-value (D160°C = 3.10 min) were used. The spores were evenly distributed on the granules, and the spore count was verified in the laboratory. The concentration range (initial contamination) was 1,000 to 1,000,000 CFU per gram. 20 ml containers filled with 15 ml of liquid CASO nutrient solution were prepared. CASO nutrient solution is a complex medium to which, in addition to glucose, proteolytically derived peptone from milk protein (casein peptone) and proteolytically derived peptone from soy flour (soy flour peptone) are added. The casein peptone is rich in free amino acids, and the soy flour peptone is characterized by a high content of carbohydrates and vitamins. Such nutrient media are particularly suitable for the cultivation of demanding microorganisms.

Over 12,000 containerized products were manufactured per test batch, whereby the analytical procedure otherwise corresponds to the content of an article from Frank Leo et al.: “Evaluation of Blow-Fill-Seal-extrusion through processing Polymer Contaminated with bacterial Spores and Endotoxin”; published in PDA Journal of Pharmaceutical Science and Technology, Vol. 58, No. 3, May-June 2004, pages 147-158 .

Reference batches (trials: reference 1 to reference 8) were produced at various temperatures, i.e., without applying the treatment zone 38 according to the invention for reducing the microbial count. The volume V of the molten plastic material between the extruder tip 22 and the die outlet was 1430 ^cm³ . The average temperature T of the molten plastic material in volume V was 170°C to 180°C. The average mass throughput of the plastic material was approximately... 50 kg/h or approximately 70 kg/h. Microbiological evaluation of these reference batches revealed reductions in bacterial count (FO) compared to the initial contamination of the granules. In example reference 2, this averaged 2100.

Batches were then produced in a similar manner, but using an additional volume Z according to the invention in the form of a treatment zone 38 or a treatment chamber 48, as described in the 1 to 3 , reproduced. The free volume Z of the additional treatment chamber 48 used was between 143 ^cm³ and 572 ^cm³ . The average temperature of the molten plastic material in the additional volume Z was 170°C to 200°C.

The use of the treatment zone 38 according to the invention in the form of the treatment chamber 48 resulted in the following microbiological evaluation of the microbiological reduction factors FM compared to the initial contamination of the granules. This factor averaged 720,000 in experiment 10, for example; thus, the additional volume Z achieved an additional improvement compared to the corresponding reference measurement (reference 4) of approximately the factor FM / FO = 720,000 / 11 = 65,455. Tests with machine bp460 with a volume V of 1430 ^cm³ at 50 and 70 kg/h Germ reduction Attempt No. throughput Volume V Temperature in V Additional volume Z Tempin Z without treatment chamber (reference) with treatment chamber Difference from the reference kg/h cm3 °C cm ³ °C Factor FO FactorFM FactorFM/FO Reference 1 50 1430 170 0 30 1 50 1430 170 286 170 60 2 2 50 1430 170 572 170 120 4 3 50 1430 170 286 185 303 10 Reference 2 50 1430 180 0 2,100 3 50 1430 180 143 180 4,600 2 4 50 1430 180 286 190 67,000 32 5 50 1430 180 143 200 100,000 48 Reference 3 70 1430 180 0 240 6 70 1430 180 143 180 410 2 7 70 1430 180 286 190 2,800 12 8 70 1430 180 286 200 59,000 246 Reference 4 70 1430 170 0 11 9 70 1430 170 429 200 44,000 4000 10 70 1430 170 572 200 720000 65455

Examples 12-20:

Analogous tests using two BFS systems of type bottelpack bp 530 from the company rommelag, Waiblingen, Germany, as also in DE 10 2020 004 564 A1 described in detail, were The tests were conducted using the plastic Purell PE 3020D from Lyondell/Basell. Even small additional volumes Z (test number 16: 77.5 ^cm³ ) and/or increased temperatures in the additional volume Z (test number 19: 200°C) resulted in very significant improvements in FM/FO in microbial reduction compared to the respective reference (reference 5 to reference 7). Details are summarized in the table below. Tests with 2 bp530 machines with a volume V of 543 and 775 cm³ ^respectively at different throughputs: with machine 530-003 for references 5 and 6 and with machine 530-001 for reference 7 Germ reduction Attempt No. throughput Volume V Temperature in V Additional volume Z Tempin Z without treatment chamber (reference) with treatment chamber Difference from the reference kg/h cm3 °C cm ³ °C Factor FO Factor FM FactorFM/FO Reference 5 15 543 170 0 79 12 15 543 170 108.6 185 350 4 13 15 543 170 217.2 195 1,600,000 20253 Reference 6 25 543 175 0 51 14 25 543 175 108.6 195 2,700 53 15 25 543 175 217.2 195 145,000 2843 Reference 7 40 775 175 0 33 16 40 775 175 77.5 195 193 6 17 40 775 175 155 185 162 5 18 40 775 175 232.5 195 6,600 200 19 40 775 175 310 200 1,600,000 48485 20 40 775 175 310 175 140 4

The aforementioned devices and methods according to the invention for minimizing microbiological contamination have the advantage that it is not necessary to sterilize an empty plastic container or even a filled container, but only the molten plastic material immediately before the container is formed and filled, followed by sealing. A further advantage of the invention is that the plastic material as a whole, and not just its surface, can be treated to reduce the number of germs.

An additional advantage is the safe and continuous documentation of the temperature-time profile of the plastic material, which is particularly important for medical purposes and is made possible by the temperature measurement sensors positioned according to the invention.

Another advantage is that the reduction in germ count takes place continuously during the production process and the inner surface of the container does not come into contact with a potentially microbiologically contaminated atmosphere or surface before it is sealed.

In the production of multi-layer containers using the BFS process, as for example in DE 103 47 908 A1 As shown, the treatment or reduction method according to the invention may be sufficient to apply only to the molten or plasticized plastic material that forms the inner layer of the respective multilayer container.

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions.

Cited patent literature

• EP 1 086 019 B1 [0002]
• DE 10 2008 032 635 A1 [0003]
• DE 10 2011 008 132 A1 [0005]
• EP 3 356 115 B1 [0006, 0026, 0041]
• DE 10 2020 004 564 A1 [0026, 0047]
• DE 10 2008 006 073 A1 [0026, 0041]
• DE 10 2020 002 077 A1 [0026]
• DE 10 2008 026 563A1 [0031]
• DE 103 47 908 A1 [0051]

Cited non-patent literature

• Domininghaus: Plastics and their properties, 5th edition 1995, page 135 [0035]
• Otto Schwarz in: Vogel Fachbuch, Kunststoffkunde, 4th edition 1992, page 66 [0035]
• Frank Leo et al.: “Evaluation of Blow-Fill-Seal-extrusion through processing Polymer Contaminated with bacterial Spores and Endotoxin”; published in the PDA Journal of Pharmaceutical Science and Technology, Vol. 58, No. 3, May-June 2004, pages 147-158 [0043]

Claims (15)

Device for producing a preform, in particular in the form of a melt tube, comprising at least an extruder (10) which can be loaded on a feed side (19) with a plastic material, in particular in granular form, and which provides a flowable plastic medium, in particular in plasticized form, on the output side, which enters the inlet side (30) of a tube head (26), which provides the preform on its discharge side (32), characterized in that at least one intermediate piece (44) is connected in a connection between the discharge side (24) of the extruder (10) and the inlet side (30) of the tube head (26) by means of individual coupling points (31), which has a treatment zone (38) which is not originally attributable to either the extruder (16) or the tube head (26) and forms an additional volume (Z) which leads to an increase in the residence time of the plastic medium in the device, and that at least during operation of the device at least one A device (40) is provided which reduces the microbial load on the plastic material within the treatment zone (28). Device according to Claim 1 , characterized in that the respective coupling point (31) is formed from a flange connection (33). Device according to Claim 1 or 2 , characterized in that the respective flange connection (33) has flanges (35) assigned to each other in pairs, each of which is part of a tubular connecting piece (39) of extruder (10), hose head (26) and intermediate piece (37) at its end, which are held together by means of a screw connection and/or can be fixed together by means of a clamp, in particular in the form of a clamp connector (41). Device according to one of the preceding claims, characterized in that the treatment zone (38) has a reactor (42) which is arranged as an intermediate piece (44) in functional areas between the discharge side (24) of the extruder (10) and the inlet side (30) of the tube head (26). Device according to one of the preceding claims, characterized in that the reactor (42) optionally comprises as a respective individual component of the treatment zone (38) at least - a container chamber (48) with an enlarged average cross-sectional area opposite an adjacent inflow and outflow side for the plastic material, and optionally additionally - a mixer (52) and/or, - a stirrer and/or, - a homogenizer. Device according to one of the preceding claims, characterized in that the container chamber (48) is widened in diameter compared to the tubular connecting pieces (39) to obtain an increased volume and/or is provided with a predefinable installation length in the case of preferably the same pipe diameter within the framework of an extension, which can also be realized by means of an arc. Device according to one of the preceding claims, characterized in that at least two individual components (48, 52) of the reactor (42) are connected in parallel or in series with respect to the fluid flow of the plastic material. Device according to one of the preceding claims, characterized in that the treatment zone (38) has one or more sensors, preferably thermocouples and/or resistance thermometers, in particular for measuring and/or controlling the temperature of the plastic material. Device according to one of the preceding claims, characterized in that the respective device (40) for reducing the microbial load has an energy emission device (54) which is arranged inside and/or outside the treatment zone (38) and is preferably a heat emission source. Device according to one of the preceding claims, characterized in that the free additional volume Z of the treatment zone (38) through which the fluid flow with the plastic material can flow is at least 50 cm ³ , preferably at least 100 cm ³ . Device according to one of the preceding claims, characterized in that the ratio of the free additional volume (Z) of the treatment zone (38) to the free volume (V) along a path (X), calculated from the screw tip (22) of an extruder screw (12) of the extruder (10) to the nozzle outlet (34) on the hose head (26), is at least 0.05, preferably at least 0.10. Method, in particular using a device according to one of the preceding claims, characterized in that the residence time of the molten or plasticized plastic material within the treatment zone (38) is at least 5 seconds, preferably at least 10 seconds, particularly preferably at least 15 seconds. Procedure according to Claim 12 , characterized in that the average temperature of the molten or plasticized plastic material in the treatment zone (38) is at least 170°C, preferably at least 180°C, particularly preferably at least 185°C. Procedure according to Claim 12 or 13 , characterized in that the average temperature of a molten or plasticized low-density polyethylene (LDPE) in the treatment zone (38) is at least 170°C, preferably at least 175°C, particularly preferably at least 180°C. Procedure according to one of the Claims 12 until 14 , characterized in that the average temperature of the molten or plasticized plastic material in the treatment zone (38) is at least 10°C, preferably at least 15°C, higher than the average temperature of the corresponding plastic material at the nozzle outlet (34) of the hose head (26).