Blow head for a blow extrusion device, method for producing a blown film, nozzle device for a blow head, base body for use in a blow head, tempering device for tempering a material melt in a blow head and blow extrusion device with a blow head

Abstract

Blow head (100) for a blow extrusion device (1000) for producing a blown film (300) from a material melt (200), comprising a nozzle device (1; 1a; 1b; 1c; 1d) in a head section (110) of the blow head (100) with an outlet opening (11) for discharging the material melt (200) as a blown film (300), wherein the nozzle device (1; 1a; 1b; 1c; 1d) has a melt channel (17) for conveying the material melt (200) to the outlet opening (11) and a tempering device (20), wherein the tempering device (20) is designed and arranged for tempering the material melt (200) in the nozzle device (1; 1a; 1b; 1c; 1d), characterized in that for a Thermal separation between a tempering section (14) of the nozzle device (1; 1a; 1b; 1c;1d) and a base section (120) of the blow head (100), which is arranged upstream of the tempering section (14) in a flow direction of the molten material (200), at least one first heat separation section (13) is configured at least partially between the tempering section (14) and the base section (120), wherein the nozzle device (1; 1a; 1b; 1c; 1d) has a base body (10) with the outlet opening (11) for discharging the molten material (200), wherein the base body (10) forms the melt channel (17) for conveying the molten material (200) to the outlet opening (11), wherein the base body (10) and the melt channel (17) are annular.

Description

The present invention relates to a blow head and to a die device for a blow extrusion device for producing a blown film from a material melt, having an outlet opening for discharging the material melt as blown film, wherein a melt channel for conveying the material melt to the outlet opening is formed in the blow head or the die device. The invention further relates to a base body and a temperature control device for use in a blow head or a die device for the blow extrusion device, wherein the temperature control device has a cooling device for cooling the material melt and a heating device for heating the material melt. The invention furthermore relates to a method for producing a blown film by means of a blown extrusion device.It is known in the prior art to use blown extrusion devices for producing blown films. In this case, a material melt is usually discharged through an outlet opening of a nozzle device as blown film and then cooled in this blow mold. Cooling is often performed from the outside and / or the inside by an air cooling device. In known die devices or in known blow extrusion devices, great care must be taken in the production or cooling of blown films.U.S. Pat. No. 5,069,612 A discloses a modular tubular extrusion head and DE 10 2013 112 028 A1 discloses an extrusion tool with a heater and a method for producing a plastic tube and extruded plastic film. WO 88 / 00 125 A1 discloses a modular extrusion head, a method and an intermediate product and a product.In the known blow extrusion devices, the material melt supplied by an extruder is formed into a tube in a blow head. After the tube has been discharged from the outlet opening of the blow extrusion apparatus, the shaped tube is blown in with cold air from the inside and / or the outside for cooling and in the process is biaxially stretched both transversely and longitudinally up to a region of a frost zone.The maximum output in known blow extrusion apparatuses is limited in most cases by the stability of the film bubble between the outlet opening and the frost zone. That is to say that the film bubble still in the form of a melt in this region becomes increasingly more labile with increasing output and can no longer be sufficiently cooled and shaped with the air stream provided. As a result, the film bubble can tear off and the installation must be started up anew.Furthermore, it has been found that, in the extrusion of blown films, in the case of certain raw material combinations of the extrudate, structural irregularities on the blown film surface frequently occur as a result of flow-induced interactions between the flowing material melt and the melt channel wall at the outlet opening of the die device.These resulting surface irregularities are also referred to as surface melt fracture or, for short, as melt fracture, which is essentially limited to the extrudate surface. In particular, the LLDPE or mLDPE plastics frequently used in the outer and inner layers often cannot be extruded in satisfactory optical film properties without adding so-called process auxiliaries. These process aids serve as additives, for example to increase the sliding properties of the plastic melt on the melt channel wall and correspondingly to reduce the friction on the melt channel wall. These additives reduce melt fractures in the extrudates. Unfortunately, such additives are expensive. Further, applications in which additives are prohibited are known. In addition, the additives or process auxiliaries mentioned can also influence the rheological properties of the plastic of the extruded film or tube. It has also been found that, in excess amounts, the additives used can influence critical tube or film properties in the opposite direction, such as gloss, haze, transparency and weldability of the film.An improvement in the blown film properties can alternatively be achieved by significantly lowering the temperature of the material melt or blown film emerging from the outlet opening. In the past, attempts have been made several times to actively cool the region in front of the outlet opening of the nozzle device below the prevailing temperatures of the material melt. However, intensive precooling in this region causes the so-called melt fracture effect and, in a blow head base body, the risk of material adhesion and thus damage to the material caused by the dwell time. Therefore, it has not been possible to realize an effective cooling of the material melt in the blow head or in a region in front of the outlet opening in practice.International patent application WO 2015 / 055162 A1 discloses first cooling the material melt in a blow extrusion device on a path through a melt channel of a die device, but heating it when it exits from the melt channel. For this purpose, a cooling device and a heating device are arranged on a base body of the nozzle device. By cooling and heating the material melt, it is possible to counteract the risk of melt fracture. However, if the base body is cooled too much by the cooling device, this acts on the downstream heating device or a corresponding heating section of the base body. If the base body is heated too strongly by the heating device, this correspondingly acts on the upstream cooling device or a corresponding cooling section of the base body. That is, if the temperature of the cooling section and / or the heating section is too high by the heating device or the cooling device, heat transfers take place between the cooling section and the heating section, which have a negative effect on the material melt. Therefore, the cooling section and / or the heating section of WO 2015 / 055162 A1 may only be tempered to a limited extent.It is an object of the present invention to at least partially eliminate the disadvantages described above. In particular, it is an object of the present invention to provide a blow head, a die device, a base body, a temperature control device, a method for producing a blown film and a blow extrusion device, wherein blown films can be produced in a rapid, simple and cost-effective manner and the risk of melt fracture can be reduced or eliminated.The above object is achieved by the claims. In particular, the above object is achieved by the blow head according to claim 1, the die device according to claim 21, the base body according to claim 22, the temperature control device according to claim 24, the method according to claim 27 and the blow extrusion device according to claim 35. Further features and details of the invention will become apparent from the description and the drawings. Features and details which are described in connection with the blow head naturally also apply here in connection with the nozzle device according to the invention, the base body according to the invention, the temperature control device according to the invention, the method according to the invention, the blow extrusion device according to the invention and vice versa, so that with regard to the disclosure reference is or can always be made reciprocally to the individual aspects of the invention.According to a first aspect of the present invention, a blow head for a blow extrusion apparatus for producing a blown film from a material melt is provided. The blow head has a nozzle device in a head section of the blow head with an outlet opening for discharging the material melt as blown film. The nozzle device has a melting channel for conveying the material melt to the outlet opening and a temperature control device. The temperature control device is designed and arranged to temperature control the material melt in the nozzle device. For a heat separation between a temperature control section of the nozzle device that can be temperature controlled by the temperature control device and a base section of the blow head, which is arranged upstream of the temperature control section in a flow direction of the material melt, at least one first heat separation section is configured at least partially between the temperature control section and the base section.The heat conduction within the nozzle device, which preferably comprises metal, in particular a steel, is significantly higher than in the plastic of the material melt. Accordingly, a heat transport within the nozzle device, for example in the temperature control section, is significantly higher than from the nozzle device or the temperature control section into the material melt. By means of the first heat separation section according to the invention, a heat transport between the temperature control section and the base section of the blow head can be reliably reduced. A transport of the heat from the temperature control section into other components or sections of the blow head can be reduced correspondingly greatly. As a result, the material melt can be locally adjusted in a particularly targeted manner. The nozzle device preferably forms a nozzle lip section or is arranged at least in a nozzle lip section.The base section is understood in the present case in particular to mean the remaining section of the blow head next to the head section which does not have the nozzle device. The base section preferably has a base body with an extruder and in particular a distributor or pivot region. In the region of the base body, temperature bridges must likewise be avoided, since this can lead to problems in the distribution and the residence time of the material melt in the distribution or pivoting region.Since a heat transport from the temperature control section into the base section has negative effects on the quality of the blown film, the first heat separation section also serves to protect against a blown film produced correspondingly in an inferior manner. The heat separating portion fundamentally separates the head portion from the base portion or forms a heat separation between the head portion and the base portion.In the present case, a heat separation is understood to mean a reduction of a heat transport from one region, for example the head section or the temperature control section, into another region, for example the base section. By means of the first heat separation section according to the invention, it is possible, in comparison with a blow head without the heat separation section according to the invention, to reduce the heat transport from the temperature control section in the direction of the base section by more than 50% during temperature control of the material melt, by more than 80% or even by more than 90% in a preferred configuration of the first heat separation section. That is to say that, in the present case, in comparison with a conventional blow head, during temperature control of the material melt, the heat transfer between the temperature control section and the base section can be reduced by more than 90%.The at least one first heat separation section is preferably designed as an annular gap between the cooling section and the base section or, at least in the cross section of the base body, as at least one groove between the cooling section and the base section. That is to say, between the cooling section and the base section, the first heat separating section forms a gap which is filled with, for example, ambient air and correspondingly heat-insulating. As already mentioned above, the heat separation in the form of an air gap or the correspondingly configured annular gap or the at least one groove is a particularly cost-effective and simple solution for producing the desired heat separation.Furthermore, it is possible within the scope of the present invention for the temperature control device to have a cooling device for cooling the material melt and a heating device for heating the material melt. That is, the heat separating portion is disposed upstream of both the cooling device and the heating device, respectively. The material melt can be controlled by the cooling device and the heating device for an advantageous quality of the blown film. The cooling section or a corresponding wall section of a base body of the nozzle device can in this case be cooled down in a targeted manner preferably up to a freezing limit or a freezing temperature of the material melt.In a blow head according to the invention, it is furthermore possible for the cooling device and / or the heating device to be of annular configuration and to be segmented in a circumferential direction and to be configured such that it can be controlled individually. As a result, a film thickness profile of the blown film can be advantageously regulated.Furthermore, in the context of the present invention, the nozzle device has a main body with an outlet opening for discharging the material melt as blown film, wherein the main body forms a melt channel for conveying the material melt to the outlet opening. The nozzle device further comprises a temperature control device, wherein the temperature control device comprises a cooling device for cooling the material melt and a heating device for heating the material melt. In addition, for a heat separation between a cooling section of the base body that can be cooled by the cooling device and a heating section of the base body that can be heated by the heating device, at least one second heat separation section is configured at least partially between the cooling section and the heating section.By the heat separation resulting from the second heat separation section between the cooling section coolable by the cooling device and the heating section heatable by the heating device, it is possible to cool or heat the cooling section by the cooling device and / or the heating section by the heating device significantly beyond a known amount without causing undesired heat transfer between the cooling section and the heating section. That is to say, the material melt can be cooled strongly in the cooling section and nevertheless be heated in a targeted manner in the heating section. By means of temperature control in such a targeted manner, i.e. a defined local limitation during cooling and heating of the material melt, any melt fracture can be prevented or at least greatly reduced at high output power.The base body and the melting channel are configured annularly for dispensing a tubular blown film. Accordingly, the outlet opening is also of annular configuration. Here, the cooling portion includes an inner cooling portion and an outer cooling portion. The inner cooling portion is configured to cool an inner side of the material melt and the outer cooling portion is configured to cool an outer side of the material melt. Accordingly, the heating section has an inner heating section and an outer heating section. The inner heating portion is configured to heat the inside of the material melt and the outer heating portion is configured to heat the outside of the material melt. Here, it is preferable that the heating portion is thermally insulated in a direction away from the melt channel. The thermal insulation can be realized, for example, by means of a PTFE unit. As a result, the melting channel or the material melt in the melting channel can be heated in a targeted manner. The heating device is preferably designed as a resistance heater. The heating device and the cooling device can also be operated via a peletier element which is arranged accordingly. The cooling device is preferably operated with oil, water and / or air. That is, the cooling device can be configured as an oil cooling device, water cooling device and / or air cooling device.The cooling and heating of the inner side and of the outer side of the material melt is to be understood in particular as influencing the temperature of the associated lateral material of the material melt. Of course, not only is the side surface of the material melt influenced, but also a temperature influence of the associated volume section of the side of the material melt is generated by heat conduction. The inside and outside of the material melt can be cooled and heated separately and independently of one another by a correspondingly independent control of the individual cooling sections and heating sections. That is to say, a different temperature control can be carried out from both sides of the material melt, with the result that, for example, one of the two sides can have a cooler temperature than the other of the two sides. Accordingly, the temperature can be influenced from both sides, for example, in such a different manner that corresponding viscosity differences in the material melt can be compensated.In the context of the present invention, the cooling and heating of the material melt is to be understood as meaning both an active and a passive cooling or heating. For example, only the side corresponding to the inner surface may be cooled or heated, while the opposite side corresponding to the outer surface is not cooled or heated.According to a development of the present invention, it is possible that in a blow head the cooling device is arranged upstream of the heating device in a flow direction of the material melt. In this case, the heating device is preferably arranged closer to the outlet opening than the cooling device. As a result, the material melt can first be cooled strongly, as a result of which the material properties of the material melt or blown film emerging from the nozzle device can be changed to the extent that a particularly high ejection speed and output can be achieved. Due to the fact that the heating device is arranged downstream of the cooling device, the material melt, before it leaves the nozzle device through the outlet opening as blown film, can be heated in such a way that the undesired melt fracture effect can be prevented or at least largely avoided. Thus, a high output power can be achieved with a simultaneously high blown film quality. If the cooling device is arranged upstream of the heating device in the direction of flow of the material melt, the cooling section of the base body is preferably also arranged or configured upstream of the heating section in the direction of flow of the material melt. The second heat separating section is preferably configured between the cooling section and the heating section in the direction of flow of the material melt.Furthermore, it is possible according to the present invention that in a blow head the at least one second heat separation section is configured as an annular gap between the cooling section and the heating section or at least in the cross section of the base body as at least one groove between the cooling section and the heating section. That is to say, between the cooling section and the heating section, the second heat separating section forms a gap which is filled with, for example, ambient air and correspondingly heat-insulating. This has the result that the temperature emanating from the cooling device locally merges into the cooling section or is limited to this. Accordingly, this leads to the temperature emanating from the heating device locally transitioning into the heating section or being limited to this. The heat separation in the form of an air gap or the correspondingly configured annular gap or the at least one groove is a particularly cost-effective and simple solution for producing the desired heat separation.In addition, it is conceivable within the scope of the present invention that in a blow head the at least one second heat separating section has a heat-insulating solid body which is arranged at least in sections between the cooling section and the heating section. A solid body between the cooling section and the heating section contributes to a high stability of the base body. Nevertheless, the heat-insulating solid body makes it possible for the temperature emanating from the cooling device to locally transition into the cooling section or be limited to this. Accordingly, the heat-insulating solid makes it possible for the temperature emanating from the heating device to locally transition into the heating section or be limited to this. The heat-insulating solid body has or consists of a material with heat-insulating properties, preferably a ceramic.Furthermore, it is possible according to the invention that in the case of a blow head, the at least one first heat separation section has a heat-insulating solid body which is arranged at least in sections between the temperature control section and the base section. As already explained above with respect to the second heat separating section, a solid body between the cooling section and the heating section contributes to a further high stability of the base body or of the nozzle device. The heat-insulating solid body in the first heat-separating section likewise has a material having heat-insulating properties, preferably a ceramic, or consists of this material.According to the invention, it can further be provided that in the case of a blow head, the cooling section has a height of between 50 mm and 120 mm, in particular a height of between 50 mm and 100 mm, in a region on the melting channel. Within the scope of the present invention, it has been found that this height is particularly suitable for bringing the material melt to the desired temperature with corresponding cooling by the cooling section. A height of between 80 mm and 100 mm has proven to be particularly preferred.It can be particularly advantageous that in a blow head according to the invention the heating section has a height of between 10 mm and 30 mm in a region on the melting channel. In the context of the present invention, it has been found that this height is particularly suitable for bringing the material melt to the desired temperature when appropriately heated by the heating section and thereby preventing melt fracture. A height of between 15 mm and 25 mm has proven to be particularly preferred.Moreover, according to the present invention, it is possible for the heating section to have a height in a flow direction of the material melt which is less than 50%, in particular less than 30%, of the height of the cooling section in the flow direction of the material melt. Since the heating section is designed in particular to heat the material melt shortly before discharge through the outlet opening in order to prevent the melt fracture effect, a correspondingly short design of the heating section is sufficient. The cooling section, on the other hand, should be designed to be significantly longer or higher in relation to the heating section in order to achieve the desired cooling of the material melt.According to a further development of the present invention, in a blow head, the melting channel has, in particular in a region on the cooling section, a narrowing and, in particular in a region on the heating section, a widening, in particular towards the outlet opening. The tapering is preferably configured downstream of the widening in the flow direction of the material melt. Such a shaping of the melt channel in the base body has shown that material deposits of the material melt at the outlet opening, which lead to a so-called nozzle bit, can thereby be prevented. In the present case, a tapering is to be understood as a reduction in the passage cross section of the melt channel. In the present case, a widening is to be understood as an enlargement of the passage cross section. Nevertheless, the cross section of the outlet opening is preferably smaller or significantly smaller than a cross section in the cooling channel.Furthermore, it is conceivable within the scope of the present invention that the base body or the nozzle device has a nozzle lip section and the heating device and / or the cooling device are arranged on or in the nozzle lip section. A nozzle lip is the section around a nozzle opening or the outlet opening. In this region, the influencing effect of the temperature control is greatest, since in this region the material melt with the outlet temperature is present. Here, therefore, the influencing of the temperatures of the two sides of the material melt can be achieved most efficiently.It can be of further advantage that in a blow head or a nozzle device according to the invention, a melt channel surface of the cooling section has a coefficient of friction in a range from 0.03 to 0.07. Thereby, adhesion of the material of the flowing material melt to the cooling portion can be reliably prevented even though the cooling portion, or a coolant temperature for the cooling device for cooling the cooling portion, is set well below the melting point of the material melt. A particularly advantageous cost / benefit ratio has been found for coating the melt channel surface of the cooling section with a coefficient of friction in a range of 0.04 to 0.06.It can also be advantageous that, in a blow head according to the invention, the cooling device is arranged at least in sections in the cooling section and / or the heating device is arranged at least in sections in the heating section. That is to say that the cooling device and / or the heating device are arranged at least in sections within the base body. As a result, the nozzle device can be designed in a particularly space-saving manner.In addition, in a blow head according to the invention, a controller for controlling and / or regulating the nozzle device is arranged, wherein the cooling device and the heating device can be controlled by the controller, in particular controlled separately from one another. As a result, a temperature control of the material melt can be automatically regulated or controlled, optionally by means of suitable temperature sensors. For this purpose, the controller has, for example, an ECU which is in communication connection with the temperature sensors of the die device or a blow extrusion device. As already mentioned above, the base body and the melt channel for dispensing a tubular blown film are preferably configured annularly. Accordingly, the outlet opening is also of annular configuration. The inner cooling portion is configured to cool an inner side of the material melt and the outer cooling portion is configured to cool an outer side of the material melt. Accordingly, the heating section has an inner heating section and an outer heating section. The inner heating portion is configured to heat the inside of the material melt and the outer heating portion is configured to heat the outside of the material melt. The controller is now preferably configured and modified in such a way that the inner side of the material melt is cooled and / or heated differently from the outer side of the material melt during the production of a blown film. This can be advantageous in particular in the production of multilayer films in which, if appropriate, an inner side is intended to be tempered differently from an outer side, in order, for example, to avoid stresses and a film tear which results therefrom. In addition, it is possible in this way that any viscosity differences in the material melt can be compensated.It can likewise be advantageous if, in the case of a blow head according to the invention, the cooling section comprises a material having a thermal conductivity of more than 200 W / (m*K). As a result, a desired heat transfer from the cooling device through the cooling section to the material melt can be ensured. It is furthermore conceivable for the entire base body or the material thereof to have a thermal conductivity of more than 200 W / (m*K).Furthermore, according to the present invention, it is possible that in a blow head or the nozzle device, the base body is configured in one piece. This leads to low production costs for the base body. In addition, the nozzle device can thereby be assembled particularly easily. In addition, the nozzle device with a one-piece base body is less prone to errors and / or maintenance compared to a nozzle device with a base body assembled from a plurality of individual parts.Furthermore, according to the present invention, it is possible for the first heat separating section and / or the second heat separating section to each have a height of less than 10 mm, preferably of less than 5 mm. By such a configuration of the base body or the respective heat separating sections, heat transfer between the cooling section and the heating section can be reliably prevented or reduced. In the present case, the height is to be understood as a height in the direction of a flow direction of the material melt. In the present case, a width is to be understood as meaning a direction orthogonal or substantially orthogonal to a flow direction of the material melt. In the direction of this width, the base body in the region of the heat separating section preferably has a thickness of less than 10 mm, particularly preferably of less than 5 mm, for example 3 mm or less. As a result, a heat separation can be achieved which leads to the desired heat separation between the cooling section and the heating section or between the cooling section and the base body. The heat separating sections can in principle be dimensioned as desired.According to another aspect of the present invention, there is provided a nozzle device for a blow head as described above. The nozzle device has a base body with an outlet opening for discharging the material melt as blown film, wherein the base body forms a melt channel for conveying the material melt to the outlet opening. In addition, the nozzle device has a temperature control device, wherein the temperature control device has a cooling device for cooling the material melt and a heating device for heating the material melt. For a heat separation between a cooling section of the base body that can be cooled by the cooling device and a heating section of the base body that can be heated by the heating device, at least one second heat separation section is configured at least partially between the cooling section and the heating section. Thus, the nozzle device according to the invention provides the same advantages as have been described in detail with reference to the blow head according to the invention. The nozzle device can of course also be further developed according to the nozzle device described above in detail. The second heat-separating section does not limit the present invention to the need for at least two heat-separating sections. The term "second" here serves merely for a better distinction from the first heat-separating section, for which reason the term "second" could also be deleted at this point.Furthermore, according to a further aspect of the present invention, a base body for use in a blow head or a nozzle device as described above is provided, wherein the base body has an outlet opening for discharging a material melt as blown film and forms a melt channel for conveying the material melt to the outlet opening. For a heat separation between a coolable cooling section of the base body and a heatable heating section of the base body, at least one first heat separation section is at least partially configured between the cooling section and the heating section. In this case, it is possible for the at least one second heat separation section to be designed as an annular gap between the cooling section and the heating section or, at least in the cross section of the main body, as at least one groove between the cooling section and the heating section. The base body according to the invention thus brings with it the same advantages as have been described in detail with reference to the blow head according to the invention or the nozzle device.Furthermore, according to the present invention, a temperature control device for controlling the temperature of a material melt in a blow head as described in detail above and / or in a nozzle device is provided. The temperature control device has at least two temperature control modules, wherein at least one first temperature control module can be operated as a cooling module and at least one second temperature control module can be operated as a heating module, and wherein at least one heat separation section is configured at least partially between the at least one first temperature control module and the at least one second temperature control module for a heat separation between the at least one first temperature control module and the at least one second temperature control module. The temperature control device brings with it the same advantages as have already been described above with respect to a correspondingly designed temperature control device. The temperature control modules can be operated as heating module or cooling module. That is, a heating module may also be operated as a cooling module at another time, and a cooling module may also be operated as a heating module at another time. Further features relating to the temperature control device, for example with respect to the heat separation section, an annular gap and / or an insulation of the temperature control modules, can be taken above from the temperature control device described with reference to the blow head.In a further development of the present invention, it is possible for the temperature control device to be of annular configuration. As a result, the temperature control device can be positioned particularly well or effectively around the melting channel. The temperature control device is configured here in an annular or substantially annular manner, wherein the annular shape is not limited to a circular annular shape but can also be configured in an elliptical or angular manner. The annular temperature control device can be positioned both in a base body of the blow head and in a nozzle section of the blow head around the melting channel. That is, a heating device occupies a larger part than a cooling device in the temperature control device. In the base body of the blow head, the temperature control device is predominantly designed as a heating device. In the nozzle section, the temperature control device is predominantly designed as a cooling device. That is, a cooling device occupies a larger part than a heating device in the temperature control device. In this case, it can also be advantageous if a heat separation section is formed between the cooling modules, at least in sections. That is to say that the respective cooling modules are designed to be thermally insulated from one another by an insulating device in this case. As a result, a coolant flow can be controlled and / or regulated individually for temperature and / or volume flow. Furthermore, this makes it possible to achieve better melt stability of the material melt at the outlet opening. The cooling modules are preferably segmented on the outside and / or on the inside over their circumference and are configured to be individually actuatable. As a result, a film thickness profile can be controlled particularly well over the circumference.It can be of further advantage within the scope of the present invention if the at least one first temperature control module and the at least one second temperature control module are arranged at least in sections radially next to one another and the thermal separation between the at least one first temperature control module and the at least one second temperature control module by the at least one thermal separation section is configured at least partially radially between the at least one first temperature control module and the at least one second temperature control module. This results in the same advantages as have been presented above with respect to the insulation between the different temperature control modules.According to a further aspect of the present invention, a method for producing a blown film from a material melt is provided, having a blow head or a nozzle device as illustrated above. In the method, the temperature control section, in particular the cooling section, is temperature controlled by the temperature control device or the cooling device during the production of the blown film at least in sections, in particular in a region on the melt channel, to a temperature below 80° C., in particular to a temperature below 50° C. Thus, the method according to the invention also brings with it the same advantages as have been described in detail with reference to the blow head according to the invention or the nozzle device. During the production of the blown film, the cooling section is preferably tempered by the cooling device at least in sections, in particular in a region on the melting channel, to a temperature of less than 50%, in particular to a temperature of less than 30%, of the temperature of the material melt in the region of the melting channel. In this case, the cooling section is tempered by the cooling device during the production of the blown film, for example, in such a way that the material melt is cooled at the cooling section by 5° to 50° C., preferably by 10° C. to 30° C. Due to the configuration of the nozzle device according to the invention, in particular due to the combination of cooling section, heat separating section and heating section, it is possible to cool the material melt at the cooling section strongly without causing the melt fracture effect.Furthermore, it is possible within the scope of a method according to the invention for the temperature control section, in particular the cooling section, to be temperature controlled by the temperature control device or the cooling device during the production of the blown film at least in sections, in particular in a region on the melting channel, in such a way that the material melt is cooled by more than 10%. This degree of tempering is also made possible in particular by the configuration according to the invention of the blow head or of the nozzle device, in particular by the combination of the tempering section or the cooling section, the second heat separating section and the heating section.In a method according to the invention, it is advantageous if the heating section is tempered by the heating device during the production of the blown film at least in sections, in particular in a region on the melting channel, to a temperature which is higher, in particular 1° C. to 3° C., higher than the temperature of the material melt at the heating section. By virtue of such a temperature control, the melt fracture effect can be prevented or at least substantially prevented.In addition, a penetration depth of the temperature increase in a region of the heating section can be more than 50%, preferably more than 75%, particularly preferably more than 85% shorter than a cross section of the material melt in this region of the heating section. That is to say, preferably only the surface of the material melt is heated or the material melt is not "heated through". In order to prevent melt fracture, it is sufficient if only the surface or an upper or outer region of the material melt is heated, preferably above the melting temperature of the material melt. The penetration depth of the temperature increase in a region of the heating section can preferably be more than 90% shorter than a cross section of the material melt in this region of the heating section.It can be of further advantage if, in a method according to the invention, the temperature-control section is designed and temperature-controlled in such a way that the material melt flows through the temperature-control section at at least two different flow rates during the production of the blown film. In this case, it is particularly advantageous if the cooling section and the heating section are designed and tempered in such a way that the material melt flows through the heating section at a higher flow rate than through the cooling section during the production of the blown film, wherein the flow rate of the material melt through the heating section is preferably 1.5 times to 15 times, particularly preferably 2 times to 10 times, higher than the flow rate of the material melt through the cooling section. Tests within the scope of the present invention have shown that particularly good results with respect to the quality of the blown film can be achieved in these ranges.According to a further aspect of the present invention, a method for producing a blown film from a material melt with a blow head is provided. The blow head has a nozzle device with an outlet opening for discharging the material melt as blown film, wherein the nozzle device has a melting channel for conveying the material melt to the outlet opening and a temperature control device. The temperature control device has a cooling device for cooling the material melt and a heating device for heating the material melt. The nozzle device includes a cooling portion coolable by the cooling device and a heating portion heatable by the heating device. The cooling section is here temperature-controlled by the cooling device during the production of the blown film at least in sections, in particular in a region on the melt channel, to a temperature below 80° C., in particular to a temperature below 50° C.According to a further aspect of the present invention, a blow extrusion apparatus is provided having a blow head as described above, a die apparatus as described above, a base body as described above and / or a temperature control apparatus as described above and / or for carrying out a method as described above. Accordingly, the blow extrusion apparatus according to the invention also brings with it the same advantages as have been described in detail with reference to the blow head according to the invention, the die apparatus according to the invention, the base body according to the invention, the temperature control apparatus according to the invention and the method according to the invention.The blow head can be oriented in the blow extrusion device for producing the blown film in the direction of gravity or counter to the direction of gravity. That is to say that the blown film can be dispensed by the correspondingly oriented blow head in the direction of gravity or counter to the direction of gravity.Further measures which improve the invention will become apparent from the following description of various exemplary embodiments of the invention, which are schematically illustrated in the figures. All features and / or advantages emerging from the claims, the description or the drawing, including structural details and spatial arrangements, can be essential to the invention both alone and in the various combinations.They show in each case schematically: FIG. 1 shows a blow head according to a first embodiment of the present invention, FIG. 2 shows a nozzle device according to the embodiment of the present invention shown in FIG. 1, FIG. 3 shows a nozzle device according to a second embodiment of the present invention, FIG. 4 shows a nozzle device according to a third embodiment of the present invention, FIG. 5 shows a nozzle device according to a fourth embodiment of the present invention, FIG. 6 shows a nozzle device according to a fifth embodiment of the present invention, FIG. 7 shows a temperature control device according to a first embodiment of the present invention, FIG. 8 shows a temperature control device according to a first embodiment of the present invention, FIG. 9 shows a temperature control device according to a third embodiment of the present invention, FIG. 10 shows a section of a blow extrusion device according to the invention, and FIG. 11 is a diagram illustrating a temperature control of a material melt according to a method of the present invention.Elements with the same function and mode of operation are provided with the same reference numerals in each of FIGS. 1 to 11.FIG. 1 shows a blow head 100 for a blow extrusion device 1000 for producing a blown film 300 from a material melt 200. The blow head 100 has a head portion 110 and a base portion 120, wherein the base portion 120 has a base body 121 and a pivot body 122. The head section 110 is located above the parting line a in FIG. 1 The swivel body 122 is located between the parting lines b and c. The base body 121 is located below the parting line c. The blow head 100 has in the head section 110 a nozzle device 1, which is described in detail with reference to FIGS. 2 to 6. The nozzle device 1 has a temperature control device 20 which is designed and arranged for the temperature control of the material melt 200 in the nozzle device 1. For a heat separation or a reduction of a heat transport between the head section 110 or a temperature control section 14 of the nozzle device 1 that can be temperature controlled by the temperature control device 20 and the base section 120 of the blow head 100, which is arranged upstream of the temperature control section 14 in a flow direction of the material melt 200, a first heat separation section 13 is configured between the temperature control section 14 and the base section 120. As can be seen in FIG. 1 by the separating lines a and b, the first heat separating section 13 partially separates the head section 110 or the temperature control section 14 from the base section 120. That is, the heat separating portion 13 is marked by the division lines a and b. The head section 110 is bounded at its lower end or at an end counter to the flow direction of the material melt 200 by the temperature control section 14 or a cooling section 15.According to the embodiment shown in FIG. 1, the first heat separation section 13 is designed as an annular gap between the temperature control section 14 and the base section 120 or, in cross section, as two grooves or indentations between the temperature control section 14 and the base section 120.FIG. 2 schematically illustrates a nozzle device 1 for producing a blown film 300 from a material melt 200 according to the embodiment illustrated in FIG. 1. The nozzle device 1 has a one-piece or monolithically produced main body 10 with an outlet opening 11 for the discharge of the material melt 200 as blown film 300. The main body 10 furthermore forms a melting channel 17 for conveying the material melt 200 to the outlet opening 11. The nozzle device 1 also has a temperature control device 20 which has a cooling device 21 for cooling the material melt 200 and a heating device 22 for heating the material melt 200. The cooling device 21 is arranged upstream of the heating device 22 in a flow direction of the material melt 200 which is illustrated by arrows according to FIG. 2.According to FIG. 2, the cooling device 21 is arranged on an inner and an outer cooling section 15 of the base body 10. According to FIG. 2, the heating device 22 is arranged on an inner and an outer heating section 16 of the base body 10. For heat separation between the cooling section 15 of the base body 10 coolable by the cooling device 21 and the heating section 16 of the base body 10 heatable by the heating device 22, the nozzle device 1 has a second heat separation section 12 configured between the cooling section 15 and the heating section 16.The second heat separating section 12 is designed as an annular gap between the cooling section 15 and the heating section 16 or, in the cross section of the base body 10, as two grooves or recesses between the cooling section 15 and the heating section 16.As is also shown in FIG. 2, the melting channel 17 has a taper in a region on the cooling section 15 and a widening towards the outlet opening 11 in a region on the heating section 16. The widening is shown relatively clearly in the figures for better visibility, but can also be significantly smaller in reality. The heater 22 and the cooler 21 are disposed at a nozzle lip portion of the base body 10 and the nozzle device 1, respectively. A melt passage surface 18 of the cooling portion 15 has a friction coefficient of 0.5.FIG. 3 schematically shows a nozzle device 1 aaccording to a second embodiment of the present invention. The second embodiment corresponds substantially to the first embodiment. In order to omit unnecessary repetition of the description, only the distinguishing features between the two embodiments will be explained below. Thus, in the nozzle device 1 aillustrated in FIG. 3, the second heat separation portion 12 includes a heat insulating solid body 12 adisposed between the cooling portion 15 and the heating portion 16. In addition, the first heat separating portion 13 includes a heat insulating solid body 13 adisposed between the cooling portion 15 and the base portion 120.FIG. 4 schematically shows a nozzle device 1 bin accordance with a third embodiment of the present invention. The third embodiment is substantially the same as the first and second embodiments. In order to omit unnecessary repetition of the description, only the distinguishing features between the embodiments will be explained below. Thus, the cooling device 21 according to the third embodiment is disposed inside the cooling portion 15, and the heating device 22 is disposed inside the heating portion 16.FIG. 5 schematically shows a nozzle device 1 caccording to a fourth embodiment of the present invention. The fourth embodiment corresponds substantially to the first embodiment and differs therefrom only in that the outlet opening 11 is of straight configuration, i.e. has no widening.FIG. 6 schematically shows a nozzle device 1 daccording to a fifth embodiment of the present invention. The fifth embodiment is substantially the same as the first embodiment and is only different therefrom in that a first heat separating portion 13' is formed not by piercing but as an annular groove or annular recesses, i.e., an inner annular recess (right in FIG. 6 ) and an outer annular recess (left in FIG. 6 ), between the cooling portion 15 and the base portion 120.FIG. 7 shows a temperature control device 20 afor controlling the temperature of a material melt 200 in a blow head 100 and / or in a nozzle device 1. The temperature control device 20 aillustrated in FIG. 7 has three temperature control modules 21 a, 22 a, 23 a, wherein two temperature control modules 21 a, 23 aare each operated as a cooling module and a further temperature control module 22 ais operated as a heating module. The heating module is located between the two cooling modules. The temperature control modules 21 a, 22 a, 23 aare, however, also switchable, so that the heating module can also be operated as a cooling module and the cooling module can also be operated as a heating module. For a heat separation between the temperature control modules 21 a, 22 a, 23 a, heat separation sections 24 a, 25 ahaving different configurations are formed between them.FIG. 8 shows a temperature control device 20 bwhich corresponds substantially to the temperature control device 20 aof FIG. 7. The temperature control device 20 bof FIG. 8 differs from the temperature control device 20 aof FIG. 7 only in the arrangement of the temperature control modules 21 b, 22 c, 23 c. According to FIG. 8, the two temperature control modules 22 b, 23 boperated as cooling modules are arranged next to one another and the temperature control module 21 boperated as a heating module is arranged next to one of the cooling modules. In this embodiment too, heat separation between the temperature control modules 21 b, 22 b, 23 bis formed between these differently configured heat separation sections 24 b, 25 b. Furthermore, the temperature control modules 21 b, 22 b, 23 bcan also be switched over here, so that the heating module can also be operated as a cooling module and the cooling module can also be operated as a heating module.FIG. 9 shows an annular temperature control device 20c. In this temperature control device 20 c, four temperature control modules 21 c, 22 c, 23 c, 24 care arranged radially or next to one another in the circumferential direction of the annular temperature control device 20 c. For a heat separation between the temperature control modules 21 c, 22 c, 23 c, 24 c, four heat separation sections 25 c, 26 c, 27 c, 28 care configured radially or in the circumferential direction of the annular temperature control device 20 cbetween the temperature control modules 21 c, 22 c, 23 c, 24.FIG. 10 schematically shows a section of a blow extrusion device 1000 having a die device 1 b, as illustrated above, in the form of a ring die. As shown in FIG. 4, the die device 1 band the blow extrusion device 1000 have a controller 30, respectively. The controller is configured to actuate the temperature control device 20 or the cooling device 21 and the heating device 22.With reference to FIGS. 1 and 11, a method for producing a blown film 300 from a material melt 200 with a blow head 100 as described above is explained below. For this purpose, a material melt 200 having a temperature of about 200° C. is first conducted through the melting channel 17 in the direction of the outlet opening 11, after the material melt in the base body 121 has been correspondingly heated. In this case, the cooling section 15 is tempered by the cooling device 21 to approximately 120° C. in a region on the melting duct 17 during the production of the blown film 300. As a result, an outer portion of the material melt 200 is cooled to about 180° C. when passing through the cooling portion 15. As a result, a particularly high ejection performance can be achieved. At the same time, the heating section 16 is heated by the heating device 22 in a region at the melting channel 17 to, for example, 195° C. As a result of the targeted, locally restricted heating of the material melt 200, an outer section of the material melt 200 is heated to approximately 183° C. in the heating section 16. As a result, an undesired melt fracture effect can be prevented during the dispensing of the blown film 300.FIG. 11 shows a diagram for illustrating the temperature control of a material melt during the present method. FIG. 11 shows a melting channel 17 with a material melt 200 located therein, which flows in the direction of the arrow to the outlet opening 11, wherein a region below the parting line y identifies the base section 120, a region between the parting lines x and y identifies the cooling section 15 and a region above the parting line x identifies the heating section 16. In addition, FIG. 11 shows two temperature characteristic curves T 1, T 2, which represent a temperature profile of the material melt 200, the thickness of which from left to right is marked as 100%, during a temperature control thereof. In the upper apex of the first temperature characteristic curve T 1, the material melt 200 has the highest temperature, in the present case about 200° C. In the lower apexes of the first temperature characteristic curve T 1, the material melt 200 has its lowest temperature, in the present case about 180° C. In the outermost region, the material melt 200 has a temperature of about 183° C. according to the first temperature characteristic curve T 1. The average temperature of the material melt 200 is there about 185° C. With respect to the second temperature characteristic curve T 2, the material melt 200 likewise has the highest temperature in the middle, that is to say in the upper apex of the second temperature characteristic curve T 2, in the present case about 200° C. In the outermost region, the material melt 200 has a temperature of about 180° C. The average temperature of the material melt 200 according to the second temperature characteristic curve T 2 is approximately 183° C.List of reference characters1; 1 a; 1 b; 1 c; 1 dnozzle device 10 main body 11 outlet opening 12 second heat separating portion 12 a: heat insulating solid 13, 13': first heat separating portion 13 a: heat insulating solid 14: temperature control portion 15: cooling portion 16: heating portion 17: melt passage 18: melt passage surface 20: temperature control device 21: cooling device 22: heating device 30: controller 100: die head 100: die head 110: head portion 120: base portion 121: base body 122: swing body 200: material melt 300: blown film 1000: blow extrusion device T 1: first temperature characteristic curve T 2: second temperature characteristic curve

Claims

Blow head (100) for a blow extrusion device (1000) for producing a blown film (300) from a material melt (200), having a die device (1; 1a; 1b; 1c; 1d) in a head section (110) of the blow head (100) with an outlet opening (11) for outlet of the material melt (200) as blown film (300), wherein the die device (1; 1a; 1b; 1c; 1d) has a melt channel (17) for conveying the material melt (200) to the outlet opening (11) and a temperature control device (20), wherein the temperature control device (20) for temperature control of the material melt (200) in the die device (1; 1a; 1b; 1c; 1d), characterized in that for a heat separation between a temperature control section (14) of the nozzle device (1; 1a; 1b; 1c; 1d) that can be temperature controlled by the temperature control device (20) and a base section (120) of the blow head (100) that is arranged upstream of the temperature control section (14) in a flow direction of the material melt (200), at least one first heat separation section (13) is at least partially configured between the temperature control section (14) and the base section (120), wherein the nozzle device (1; 1a; 1b; 1c; 1d) has a base body (10) with the outlet opening (11) for discharging the material melt (200), wherein the base body (10) forms the melting channel (17) for conveying the material melt (200) to the outlet opening (11), wherein the base body (10) and the melting channel (17) are configured annularly.Blow head (100) according to claim 1, characterised in that the temperature control device (20) has a cooling device (21) for cooling the material melt (200) and a heating device (22) for heating the material melt (200).Blow head (100) according to claim 2, characterised in that the cooling device (21) and / or the heating device (22) is configured annularly and segmented in a circumferential direction and configured individually actuatable.Blow head (100) according to claim 2 or 3, characterised in that for a heat separation between a cooling section (15) of the base body (10) that can be cooled by the cooling device (21) and a heating section (16) of the base body (10) that can be heated by the heating device (22), at least one second heat separation section (12) is configured at least partially between the cooling section (15) and the heating section (16).Blow head (100) according to one of Claims 2 to 4, characterized in that the cooling device (21) is arranged upstream of the heating device (22) in a flow direction of the material melt (300).Blow head (100) according to claim 4 or 5, characterised in that the at least one second heat separation section (12) is designed as an annular gap between the cooling section (15) and the heating section (16) or at least in the cross-section of the base body (10) as at least one groove between the cooling section (15) and the heating section (16).Blow head (100) according to one of claims 4 to 6, characterised in that the at least one second heat separating section (12) has a heat-insulating solid body (12'), which is arranged at least in sections between the cooling section (15) and the heating section (16).Blow head (100) according to one of claims 1 to 7, characterised in that the at least one first heat separation section (13) is designed as an annular gap between the cooling section (15) and the base section (120) or at least in the cross-section of a section of the nozzle device (1; 1b) as at least one groove between the temperature control section (14) and the base section (120).Blow head (100) according to one of claims 1 to 8, characterised in that the at least one first heat separating section (13) has a heat-insulating solid body (13'), which is arranged at least in sections between the temperature control section (14) and the base section (120).Blow head (100) according to one of claims 2 to 9, characterised in that the cooling section (15) has a height between 50 mm and 120 mm, in particular a height between 50 mm and 100 mm, in a region on the melting channel (17).Blow head (100) according to one of claims 2 to 10, characterised in that the heating section (16) has a height between 10 mm and 30 mm in a region on the melting channel (17).Blow head (100) according to one of claims 2 to 11, characterised in that the heating section (16) has a height in a flow direction of the material melt (200) which is less than 50%, in particular less than 30%, of the height of the cooling section (15) in the flow direction of the material melt (200).Blow head (100) according to one of Claims 2 to 12, characterized in that the melting channel (17) has, in particular in a region on the cooling section (15), a taper and, in particular in a region on the heating section (16), a widening, in particular towards the outlet opening (11).Blow head (100) according to one of claims 2 to 13, characterised in that the base body (10) or the nozzle device (1; 1a; 1b; 1c; 1d) has a nozzle lip section and the heating device (22) and / or the cooling device (21) are arranged on or in the nozzle lip section.Blow head (100) according to one of claims 2 to 14, characterized in that a melt channel surface (18) of the cooling section (15) has a coefficient of friction in a range of 0.03 to 0.07.Blow head (100) according to one of claims 2 to 15, characterised in that the cooling device (21) is arranged at least in sections in the cooling section (15) and / or the heating device (22) is arranged at least in sections in the heating section (16).Blow head (100) according to one of Claims 2 to 16, characterized in that a controller (30) for controlling and / or regulating the nozzle device (1b) is arranged, and the cooling device (21) and the heating device (22) can be controlled by the controller (30), in particular can be controlled separately from one another.Blow head (100) according to one of claims 2 to 17, characterized in that the cooling section (15) comprises a material having a thermal conductivity of more than 200 W / (m*K).Blow head (100) according to one of Claims 3 to 18, characterized in that the basic body (10) is configured in one piece.Blow head (100) according to one of claims 1 to 19, characterised in that the second heat separating section (12) and / or the first heat separating section (13) each have a height of less than 10 mm, in particular a height of less than 5 mm.Nozzle device (1; 1a; 1b; 1c; 1d) for a blow head (100) according to one of claims 1 to 20, having a base body (10) with an outlet opening (11) for discharging the material melt (200) as blown film (300), wherein the base body (10) forms a melt channel (17) for conveying the material melt (200) to the outlet opening (11), and a temperature control device (20), wherein the temperature control device (20) has a cooling device (21) for cooling the material melt (200) and a heating device (22) for heating the material melt (200), characterized in that, wherein, for a heat separation between a cooling section (15) of the base body (10) that can be cooled by the cooling device (21) and a heating section (16) of the base body (10) that can be heated by the heating device (22), at least one second heat separation section (12) is at least partially configured between the cooling section (15) and the heating section (16), wherein the base body (10) and the melting channel (17) are configured annularly.Base body (10) for use in a blow head (100) and / or a nozzle device (1; 1a; 1b; 1c; 1d) according to one of Claims 1 to 21, wherein the base body (10) has an outlet opening (11) for discharging a material melt (200) as blown film (300) and forms a melt channel (17) for conveying the material melt (200) to the outlet opening (11), characterized in that, for a heat separation between a coolable cooling section (15) of the base body (10) and a heatable heating section (16) of the base body (10), at least one second heat separation section (12) is at least partially configured between the cooling section (15) and the heating section (16), wherein the base body (10) and the melt channel (17) are configured annularly.Base body (10) according to claim 22, characterised in that the at least one first heat separation section (12) is designed as an annular gap between the cooling section (15) and the heating section (16) or at least in the cross-section of the base body (10) as at least one groove between the cooling section (15) and the heating section (16).Temperature control device (20a; 20b; 20c) for the temperature control of a material melt (200) in a blow head (100) according to one of claims 1 to 20 and / or in a nozzle device (1; 1a; 1b; 1c; 1d) according to claim 21, characterised in that the temperature control device (20a; 20b; 20c) has at least two temperature control modules (21a, 22a, 23a; 21b, 22b, 23b; 21c, 22c, 23c, 24c), wherein at least one first temperature control module (21a, 23a; 22b, 23b; 21c, 23c) can be operated as a cooling module and at least one second temperature control module (22a; 21b; 22c, 24c) can be operated as a heating module, and wherein, for a heat separation between the at least one first temperature control module (21a, 23a; 22b, 23b; 21c, 23c) and the at least one second temperature control module (22a; 21b; 23c, 24c), at least one heat separation section (24a, 25a; 24b, 25b; 25c, 26c, 27c, 28c) is configured at least partially between the at least one first temperature control module (21a, 23a; 22b, 23b; 21c, 23c) and the at least one second temperature control module (22a; 21b; 22c, 24c).Temperature control device (20c) according to claim 24, characterised in that the temperature control device (20c) is of annular configuration.Temperature control device (20c) according to Claim 25, characterized in that the at least one first temperature control module (21c, 23c) and the at least one second temperature control module (23c, 24c) are arranged at least in sections radially next to one another, and the thermal separation between the at least one first temperature control module (21c, 23c) and the at least one second temperature control module (23c, 24c) by the at least one thermal separation section (25c, 26c, 27c, 28c) is designed at least partially radially between the at least one first temperature control module (21c, 23c) and the at least one second temperature control module (22c, 24c).Method for producing a blown film (300) from a material melt (200), having a blow head (100) according to one of Claims 1 to 20 and / or a nozzle device (1; 1a; 1b; 1c; 1d) according to Claim 21.Method according to claim 27 characterised in that the temperature control section (14), in particular the cooling section (15) in the temperature control section (14), is temperature controlled by the temperature control device (20) or the cooling device (21) during the production of the blown film (300) at least in sections, in particular in a region on the melting channel (17), in such a way that the material melt is cooled by more than 10%.Method for producing a blown film (300) from a material melt (200) with a blow head (100) according to one of Claims 1 to 20 and / or a nozzle device (1; 1a; 1b; 1c; 1d) according to Claim 21, characterized in that the cooling section (15) is tempered by the cooling device (21) at least in sections, in particular in a region on the melting duct (17), to a temperature below 80°C, in particular to a temperature below 50°C, during the production of the blown film (300).Method (1) according to one of Claims 27 to 29, characterized in that, during the production of the blown film (300), the heating section (16) is temperature-controlled by the heating device (22) at least in sections, in particular in a region on the melting duct (17), to a temperature which is higher, in particular 1°C to 3°C higher, than the temperature of the material melt (200) on the heating section (16).Method (1) according to one of Claims 27 to 30, characterized in that a penetration depth of the temperature increase in a region of the heating section (16) is more than 50%, preferably more than 75%, particularly preferably more than 85% shorter than a cross section of the material melt (200) in this region of the heating section (16).Method (1) according to one of Claims 27 to 31, characterized in that the temperature-control section (20) is designed and temperature-controlled in such a way that the material melt (200), during the production of the blown film (300), flows through the temperature-control section (20) at at least two different flow speeds.Method (1) according to claim 32, characterised in that the cooling section (15) and the heating section (16) are designed and tempered in such a way that the material melt (200), during the production of the blown film (300), flows through the heating section (16) at a higher flow rate than through the cooling section (15), wherein the flow rate of the material melt (200) through the heating section (16) is preferably 1.5 times to 15 times, particularly preferably 2 times to 10 times higher than the flow rate of the material melt (200) through the cooling section (15).Method for producing a blown film (300) from a material melt (200) having a blown head (100), wherein the blown head (100) has, in a head section (110) of the blown head (100), a nozzle device (1; 1a; 1b; 1c; 1d) having an outlet opening (11) for discharging the material melt (200) as blown film (300), wherein the nozzle device (1; 1a; 1b; 1c; 1d) has a melting channel (17) for conveying the material melt (200) to the outlet opening (11), a temperature control device (20) and a base body (10), wherein the base body (10) has the outlet opening (11) for discharging the material melt (200), wherein the base body (10) forms the melting channel (17) for conveying the material melt (200) to the outlet opening (11), and the temperature control device (20) has a cooling device (21) for cooling the material melt (200) and a heating device (22) for heating the material melt (200), wherein the nozzle device (1; 1a; 1b; 1c; 1d) has a cooling section (15) coolable by the cooling device (21) and a heating section (16) heatable by the heating device (22), characterized in that the cooling section (15) is tempered by the cooling device (21) at least in sections, in particular in a region on the melt channel (17), to a temperature below 80° C., in particular to a temperature below 50° C., during the production of the blown film (300), wherein the main body (10) and the melt channel (17) are configured annularly.Blow extrusion device (1000) with a blow head (100) according to one of claims 1 to 20, a die device (1b) according to claim 21, a base body (10) according to one of claims 22 to 23, a temperature control device (20) according to one of claims 24 to 26 and / or for carrying out a method according to one of claims 27 to 34.

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