DE102021118705A1 - Device and process for biaxial plastic extrusion - Google Patents

Abstract

A device for producing an at least one-layer extruded tubular preform (V2-V10) made of thermoplastic material comprises an extrusion head (50) in which a distributor ring (52) is arranged. This has two downwardly open flow channels (58, 59) and two deflection units (54) which prevent the material melts (M1, M2) flowing toward one another from spreading horizontally in the respective flow channel (58, 59) and the material melts (M1, M2) redirect down.

Description

The invention relates to a device for producing an at least one-layer extruded tubular preform made of thermoplastic material, preferably polyethylene (PE). Furthermore, the invention relates to a method for producing a preform and a method for producing a plastic component using the blow molding method.

From the WO 2005/097462 A1 is an extrusion line known, the structure below in connection with 1 is explained in more detail. This extrusion system can be used to produce preforms with a plurality of coaxially arranged layers made of different materials, with each layer having the same plastic material when viewed in the circumferential direction.

It is the object of the invention to specify a device for producing a tubular preform which, viewed in the circumferential direction of the preform, has different plastic materials. Furthermore, it is the object of the invention to specify a method for producing a preform and a method for producing a plastic component which has layers with different plastic material.

This object is achieved by the features of claim 1 for a device. Advantageous developments are specified in the dependent claims.

With regard to a production method, the stated object is achieved by the features of claim 14. Further developments are specified in the dependent claims.

According to the invention relating to a device, a first distributor ring contains a deflection unit at predetermined deflection positions, which prevent the material melts flowing towards one another from spreading horizontally in the respective flow channel and deflect the material melts downwards and only bring them together again at the lower end of the deflection unit. In this way, different material melts are guided largely separately from one another into the annular storage space. A plurality of material melts are ejected from this annular storage space as a preform, which, seen in the circumferential direction, can have two or more plastic materials which differ, for example, in their colors.

In the new extrusion head, several distributor rings of the type of the first distributor ring can be arranged one above the other. Each of these first distribution rings can dispense different melts of material forming a hollow cylinder layer in the preform. This layer of hollow cylinders is divided in length, so that one elongate segment of this hollow cylinder contains a first plastic material and another segment contains a different plastic material.

The technical advantage of biaxial (or, as shown below, multiaxial) extrusion within a layer is that the materials used in the material melts and the respective layer thicknesses within a layer can be different and can be combined with one another. In the simplest case, one material can be colored differently than the other, which has an advantageous effect in the finished two-tone blow molded product. For example, an underside of this product can have a different color than its top. Furthermore, a material within a layer in the preform can have a different layer thickness and thus different mechanical strength properties in the blow molded product. The materials of a biaxial (or multiaxial) layer can also differ with regard to material properties, e.g. with regard to toughness, mechanical strength and electrical properties.

An advantageous development provides that at least one further distributor ring is arranged coaxially to the first distributor ring, to which another material melt is fed, which is distributed in a ring shape all around in the associated discharge ring and fed downwards to the common flow channel, in which it is mixed with the material melts from the first Distribution ring are included in coaxial juxtaposition. In this way, a plurality of distribution rings of the type of the first distribution ring as well as of the type of the second distribution ring can be arranged in the extrusion head and a large number of variations of abutting plastic materials can be realized in a parison.

A further advantageous embodiment provides that the distributor ring contains deflection units at more than two deflection positions, which deflect the material melts flowing toward one another downwards. In this way, a parison having multiple plastic materials within a single layer can be produced by multi-axis extrusion.

According to a further aspect of the invention, a method for producing a preform and for producing a plastic component using the blow molding method is specified. This manuf driving uses a preform that is produced with the device described.

• 1 einen teilweisen Querschnitt durch eine Extrusionsanlage nach dem Stand der Technik zum Herstellen eines koaxialen Vorformlings,
• 2 einen monoaxialen Vorformling,
• 3 einen einschichtigen biaxialen Vorformling im Querschnitt und in einer perspektivischen Darstellung,
• 4 einen zweischichtigen biaxialen Vorformling,
• 5 einen biaxialen Vorformling mit drei Schichten,
• 6 einen Extrusionskopf zum Herstellen biaxialer Vorformlinge,
• 7a einen Vorformling umfassend Kunststoff-Materialien M1 bis M6,
• 7b einen Vorformling mit unterschiedlichen Schichtdicken,
• 7c einen Vorformling mit zusätzlicher innerer monoaxialer Schicht,
• 8 einen Teil-Längsschnitt durch den Verteilerring,
• 9 eine Draufsicht mit mehreren Segmenten des Verteilerrings,
• 10 die Anordnung verschiedener Segmente im Verteilerring für einen Winkelbereich von 180°,
• 11 die Verteilung der Segmente des Verteilerrings für einen Winkelbereich von 90°,
• 12 einen Vertikalschnitt durch die Umlenkeinheit,
• 13 einen Längsschnitt durch die Umlenkeinheit,
• 14 einen weiteren Querschnitt durch die Umlenkeinheit von oben gesehen,
• 15 einen biaxialen Vorformling mit einem Winkelbereich für ein Material von 90°,
• 16 einen zweischichtigen biaxialen Vorformling, und
• 17 einen dreiachsigen, zweischichtigen Vorformling.

An example of the prior art and exemplary embodiments according to the invention are illustrated and described below in the figures. It shows:

• 1 a partial cross section through a prior art extrusion line for producing a coaxial parison,
• 2 a monoaxial preform,
• 3 a single-layer biaxial preform in cross section and in a perspective view,
• 4 a two-layer biaxial preform,
• 5 a three layer biaxial preform,
• 6 an extrusion head for producing biaxial preforms,
• 7a a preform comprising plastic materials M1 to M6,
• 7b a preform with different layer thicknesses,
• 7c a preform with additional inner monoaxial layer,
• 8th a partial longitudinal section through the distribution ring,
• 9 a top view with several segments of the distribution ring,
• 10 the arrangement of different segments in the distributor ring for an angle range of 180°,
• 11 the distribution of the segments of the distribution ring for an angular range of 90°,
• 12 a vertical section through the deflection unit,
• 13 a longitudinal section through the deflection unit,
• 14 another cross-section through the deflection unit seen from above,
• 15 a biaxial preform with an angle range for a material of 90°,
• 16 a two-layer biaxial preform, and
• 17 a triaxial, bilayer preform.

The present invention relates to a further development in the WO 2005/097462 A1 described extrusion line. The content of this document is included in the disclosure content of the present application. In the present 1 is a coextrusion head 10 based on the above WO 2005/097462 A1 partially shown in longitudinal section. It comprises a storage casing 8 which surrounds a ring storage space 14 which accommodates the material melts to be ejected. The storage shell 8 is connected to a housing, not shown. A material melt is fed via an inflow opening ZF1 to a distributor ring 26 which belongs to an annular piston 16 . This annular piston 16 can be displaced along its longitudinal axis and slides along a sleeve 6 and the accumulator jacket 8. The annular piston 16 is connected to a hydraulic device (not shown) via piston rods K1, K2. Likewise, the quill 6 is connected at its upper end to a hydraulic device (not shown). During operation, the extrusion head 10 stands vertically with its longitudinal axis m on a flat base and the terms “top, bottom, horizontal, vertical, etc.” are also unambiguous and clear with regard to the function of the extrusion head for the present innovation.

The material melt is conveyed horizontally along the distributor ring 26 and at the same time flows downwards along an annular truncated cone channel 40 which is formed along a truncated cone surface of the annular piston 16 . The downwardly flowing molten material then reaches a cylinder ring 22 and from there to an orifice 30, where a second molten material opens out. This second material melt is supplied via a second feed opening ZF2 arranged diametrically to the feed opening ZF1, is also distributed from there via an associated circumferential distribution ring 28 and reaches an annular second truncated cone channel 44. From there, the second material melt flows to the outlet point 30.

The flow of the two material melts should take place in such a way that the boundary surface as a cylindrical surface between the two material melts is as smooth as possible and is not disturbed by vortices. A calming section, which is designed as a common cylinder ring 34 , connects to the opening 30 . This calming section ensures that after the material melts have been combined at the outlet point 30, the two material melts flow evenly, as a result of which the cylinder jacket boundary surface between the two material melts runs smoothly. The two material melts then flow to an expansion point 32, where the two material melts open into an expanding common flow channel 12. This flow channel 12 has in cross section a funnel shape with lateral surfaces 36, 38 and is ring-shaped in the annular piston 16.

At the beginning of the filling process, the annular piston 16 is in its lower position, as indicated schematically by dashed lines in connection with the reference number 15 . The funnel-shaped common flow channel 12 is still filled with the two material melts from the previous production process for producing a tubular preform V1. The annular piston 16 is moved upwards by the subsequent flow of the two material melts. Due to the funnel shape of the common flow channel 12 and the additional geometry for guiding the material melt, the boundary surface formed between the two material melts remains largely smooth and is not swirled.

When the annular piston 16 has reached its upper operating point, the quill 6 is moved downwards and opens an annular nozzle gap 20 with its nozzle mushroom 6a, so that when the annular piston 16 moves downwards, a tubular preform V1 is ejected with the interface between the two material melts . In order to maintain the smooth progression of the boundary surface, an annular discharge channel 18 is designed to taper in its geometry towards the nozzle gap 20 . With the completion of the ejection process, the quill 6 is moved upwards again and closes the nozzle gap 20, whereupon a new filling process for the annular storage space 14 begins.

2 shows a perspective view and a cross section through the two-layer preform V1, the material of an inner first layer S1 of which differs from the material of the outer second layer S2. The sequence of layers in the preform V1 corresponds to that which is present in the cross section for the material melts in the lower common cylinder ring 34 . Viewed in the direction of extrusion P1, the respective material in the layers S1, S2 is the same in the form of hollow cylinders or jacket layers. In the circumferential direction P2, each layer S1 or S2 consists of the same material all around. By definition, the preform V1 is a monoaxial, multilayer, coaxial preform. It is desirable to produce another type of parison having at least two different materials within one layer S1, S2 in the direction of extrusion. This is hereinafter referred to as biaxial layering and for the process as biaxial extrusion.

3 1 shows a cross-section and a perspective view of a single-layer, biaxial preform V2 produced in an extrusion system according to the invention. To produce this preform V2, a feed E1 at an associated feed opening with a material melt M1 and a feed E2 with a material melt M2 different from M1 take place in an extrusion head. Viewed in the circumferential direction P2, the layer S1 is composed of the materials M1 and M2, which are largely sharply delimited from one another at boundary surfaces G1. For example, materials M1 and M2 have different colors, as shown in FIG 3 is indicated hatched. After being fed in, the material melts M1 and M2 spread out in the circumferential direction via E1 or E2, as indicated by arrows, into corresponding flow channels (see Fig 6 ) the end. Seen in the direction of extrusion, the preform V2 is composed of two hollow cylinder segments, namely one with material M1 along a first longitudinal axis P3 and another segment with material M2 along a second longitudinal axis P4, which is why we speak of biaxial extrusion. For the sake of a simplified description, material melts are denoted by M1, M2, M3 .

4 Figure 12 shows a two layer biaxial preform V3 extruded via four feeds E1, E2, E3, E4 with three different material melts M1, M2 and M3. The outer layer S2 consists of the different materials M1, M2 seen in the circumferential direction P2. Although the inner layer S1 is fed from two feeds E3 and E4, it consists of the same material M3; this layer S2 is therefore monoaxial by definition.

5 shows another preform V4, which is constructed biaxially and comprises three layers S1, S2 and S3. It is fed from feeds E1 to E6 with material melts M1 to M5. Outer layer S3 is biaxial and contains material M1 and M2 extruded from feeds E1 and E2. The layer S2 is monoaxial and is made up of the material M3, which is extruded from the two facing feeds E3 and E4, continuously all around. The innermost layer S1 is again biaxial and comprises the different materials M4 and M5 from feeds E5 and E6.

6 12 shows schematically an extrusion head 50 according to the invention for producing a multi-layer biaxial and monoaxial parison. Traits with traits after 1 match are labeled the same. The annular piston 16 includes an upper cone portion 16a, an upper ring 16b, a middle ring 16c and a lower ring 16d. The cone portion 16a includes an upper biaxial first distribution ring 52 in which is circumferentially at two opposed Deflection positions Z1, Z2 (cf. 8th and 9 ) a deflection unit 54 is arranged in each case. A first material melt M1 or a second material melt M2 is fed in via feed openings 56 and 57 located opposite one another on both sides of the first distribution ring 52 Flow ring, which is designed as an annular truncated cone channel 60, continue to flow. An upper part 54a of the deflection unit 54 is arranged in the distribution ring 52 and prevents the horizontal spread of the respective material melt M1, M2 in the circumferential direction in the flow channels 58, 59. A lower part 54b of the deflection unit 54 projects into the truncated cone channel 60 (and possibly further from there ) and also prevents the material melts M1, M2 flowing towards one another from both sides from flowing together there. The lower part 54b of the deflection unit 54 opens into a separating web 62, which prevents the merging of the melts M1, M2 at least within a section of the truncated cone channel 60 and possibly beyond. The material melts M1 and M2 reach an upper cylinder ring 64, where they are combined with other material melts at an opening point 66.

The lower parts 54b of the two turning units 54 are supported by an upper annular flow insert 68 which is arranged below the first distributor ring 52 . Distribution ring 52 and flow insert 68 are separate components.

The annular piston 16 contains a further distributor ring 70 between its upper ring 16b and its middle ring 16c to form a monoaxial layer. Such a distributor ring 70 is also called a monoaxial distributor ring. Its two feed openings for another material melt M3 are in the 6 not to be seen. Seen in the circumferential direction, they are each offset by a predetermined angle with respect to the feed openings 56, 57. The material melt M3 flows down a truncated cone channel 72 to an orifice 66 where it comes into contact with the material melts M1 and M2 of the inner layer of the biaxial preform to be manufactured. From there, the material layers M1 to M3 flow in the middle cylinder ring 73, the ring diameter of which is larger than that of the upper cylinder ring 64, down to a lower opening point 74, where a third layer, an outer biaxial layer, opens out. A second flow insert 76 can be present for the further distributor ring 70 .

Furthermore, the annular piston 16 contains a lower distribution ring 80, which is constructed analogously to the first distribution ring 52, with feed openings 82, 83 via which a fourth material melt M4 and a fifth material melt M5 are fed. The material melts M4, M5 enter a lower truncated cone channel 81 formed between the middle ring 16c and the lower ring 16d. As can be seen in the detail, the lower distribution ring 80 also contains at two specified deflection positions Z1, Z2 (in 6 only Z1 is drawn in), which correspond to the deflection positions for the first distributor ring 52, in each case a deflection unit 84, an upper part 84a and a lower part 84b, which opens into a separating web 86. The position of the separating webs 62 for the distributor rings 52 and 80 corresponds to the deflection position Z1. The lower portion 84b is held in place by a lower annular flow insert 88 .

After the opening 74, three adjacent coaxial layers S1, S2 and S3 flow down into a third common cylinder ring 90 with a correspondingly larger ring diameter and from there into the common flow channel 12 and into the ring storage space 14 (cf. 1 ), from where a multilayer biaxial and monoaxial preform V5 is ejected. In this lowermost common cylinder ring 90, all layers are arranged coaxially and have the same flow rate.

7a shows a cross section of the structure of the preform V5 with the layers S1, S2, S3, which correspond to the arrangement in the cross section in the common cylinder ring 90 with the material melts M1 to M5. The inner layer S1 contains the material M1 and the material M2 as seen in the circumferential direction. The middle layer S2 contains the material M3 all around. The outer layer S3 contains the materials M4 and M5. The layer structure in the cross section of the preform V5 corresponds to the layer structure in the cross section of the common third annular channel 90 in which the material melts M1 to M5 flow coaxially while maintaining their boundary surfaces G1 and G2.

The embodiment of the extrusion head 50 after 6 can be modified constructively. As a cone, the cone part 16a expediently also defines the shape for the outflow channels, which in 6 are designed as truncated cone channels 60, 72 and 81. This truncated cone shape is advantageous for the structural design and for the flow behavior of the material melts. These outflow channels 60, 72, 81 can also have other shapes, for example they can have a largely horizontal course or a shape approximated to a spherical shape.

Another variant of the embodiment according to 6 provides that the material melt M3 for the monoaxial layer S2 is only at one point of the distributor ring 70, as shown in 1 shown and in the mentioned WO 2005/097462 A1 is described.

A further variant provides for the middle distributor ring 70 to be in the form of a biaxial distributor ring analogous to the first distributor ring 52 with a corresponding outflow channel. Correspondingly, the middle layer S2 can then have two material layers in the circumferential direction.

The embodiment after 6 can be expanded with further distributor rings, which are constructed as biaxial distributor rings analogous to the first distributor ring 72 and/or as monoaxial distributor rings analogous to the further distributor ring 70. Different types of preforms can be produced by combining different biaxial distributor rings and monoaxial distributor rings, as will be described below.

7b shows an example of a layer structure of a complex preform V6, which has semicircular partial layers H1 to H5 viewed in cross section. Each sub-layer H1 to H5 can have different material M1 to M5, which is fed in molten form via feeds E1 to E5. Deflection units 54 with associated separating webs 62 arranged at the deflection positions Z1, Z2 prevent the material melts M1 to M5 from mixing. As in 7b As can be seen, the thickness of layer H1 is greater than the thickness of either layer H4 or H3. Such different layer thicknesses for individual biaxial layers are possible as long as the total thickness of the layers of the material melts is constant in the radial direction in the common bottom cylinder ring 90 . Five biaxial distributor rings are required to produce preform V6.

7c shows a preform V7, similar to V6, but additionally with an inner circumferential monoaxial layer S0 with material M0. This layer S0 can be produced conventionally, for example as mentioned in FIG WO 2005/097462 A1 is described. It can also be made using a biaxial distribution ring by feeding the same material at its two feeds, with both semi-circular cross-section material melts rejoining as they flow downwards.

8th shows in a partial longitudinal section along the feed openings 56-57 in 6 Details of the course, indicated by arrows, of the supplied material melts M1 and M2 in the biaxial first distribution ring 52 with the flow channels 58, 59. The material melts M1 and M2 flowing toward one another are prevented from spreading horizontally by the deflection unit 54 and the material melts M1, M2 correspond to the indicated ones Out arrows down and along the separating web 62, which protrudes at least into the first truncated cone channel 60. The position of the separating web 62 defines the deflection position Z1 (or Z2 on the opposite side) in the circumferential direction. The flow channels 58, 59 are open at the bottom with a predetermined gap width, so that the material melts M1, M2 flow down in their respective semicircle segment into the truncated cone channel 60. A lower part of the deflection unit 54 is arranged on the annular separate flow insert 68 .

9 shows a plan view of the first distributor ring 52. The deflection units 54 are arranged at the deflection positions Z1, Z2, and prevent the further horizontal flow of the material melts M1 and M2. It is advantageous if the distribution ring is divided into sectors 52a, 52b, 52c, 52d. The sectors 52a and 52c then contain the feed openings 56, 57 for the material melts M1 and M2, respectively; the sectors 52b and 52d each contain a deflection unit 54.

the 10 and 11 show an advantageous variant, according to which the distributor ring 52 is divided into four segments 52a, 52b, 52c, 52d, which are at interfaces Ta, Ta; Tb, Tb; Tc, Tc; Td, Td are separable from each other. In the same way, the associated annular flow insert 68 is divided into four segments (not shown). The segments 52b and 52d each contain a part of the deflection device 54; likewise the associated segment of the flow insert 68. The material melts M1, M2 or the corresponding materials M1, M2 in the preform each comprise a semicircle. According to 11 the different segments are put together differently. The segment 52b with its one separating surface Tb is assigned to the infeed E2, as is the segment 52d with its separating surface Td. The segment 52a lies with its one parting surface Ta at the level of the feed E1, as does the segment 52c with Tc. As can be seen, the deflection devices 54 of the segments 52b and 52d and the associated deflection positions Z1 and Z2 now enclose an angular range of 90° for the material M2 and of 270° for the material M1. The segmentation made makes it possible to vary the angular ranges for materials in biaxial extrusion without requiring extensive intervention in the machine structure. According to the principle described, a subdivision into more than four segments (e.g. eight segments) can be advantageous in order to define the angular ranges for two deflection positions Z1, Z2 or to vary for more than two deflection positions.

12 shows a schematic vertical section through the deflection unit 54 and the biaxial distribution channel 52. The upper part 54a is formed in the deflection unit 54 and has an inwardly concave surface 55 on each side of the onflowing material melts M1, M2 (in 12 the central curved line is drawn in), which tapers in the direction of the truncated cone channel 60 to the separating web 62, at the end 63 of which the two material melts M1, M2 abut and continue to flow downwards largely separately from one another. The lower part 54b of the deflection unit 54 is mounted on the ring-shaped flow insert 68 and its side walls 53, which are also concavely curved inwards, connect smoothly to the deflection surfaces 55. In this way, a largely turbulence-free deflection of the melts M1, M2 at the deflection positions Z1, Z2 is ensured. The length of the narrow separating web 62 is selected in such a way that a sufficiently sharp separation is ensured when the melts M1, M2 continue to flow past the end 63. It can be up to the height of the respective mouth point 66 or 74 (see 6 ) be guided. The further this separating web 62 is guided with its end 63 downwards to the respective opening points 66, 74 and possibly beyond them, the sharper the separation. The end 63 of the separating web 62 preferably protrudes into the lowermost cylinder ring (in 6 the cylinder ring 90) where all material melts are arranged coaxially before continuing into the common funnel-shaped flow channel 12. Here, the separating web 62 tapers from, for example, 8 mm to 2 mm.

The design of the deflection surfaces 55 and the side walls 53 have the shape of the upper section of a heart, as shown in 12 is sketched below with solid lines. In this respect, the curvature of the deflection unit 54 is heart-shaped in its upper part 54a and its lower part 54b (without the separating web 62).

13 shows a longitudinal section through the deflection unit 54 with the upper part 54a, the lower part 54b and the web 62 which protrudes into the first truncated cone channel 68. The upper part 54a is formed in the first distributor ring 52 between the two flow channels 58,59. These flow channels 58, 59 are open at the bottom and have a gap width 51, which results between a lower edge 61 and the upper ring part 16b. The lower part 54b is mounted on the flow insert 68 and connects to the upper part 54a at the top and to the separating web 62 which runs in the truncated cone channel 60 at the bottom.

14 shows a cross section through the deflection unit 54 seen from above. The material melts M1 and M2 are diverted downwards into the first truncated cone channel 60 by the diverting unit 54 .

the 12 until 14 show a preferred embodiment of the deflection unit 54. It has the technical advantage that the incoming material melts M1, M2 are deflected in a streamlined manner and a disruptive deposit of plastic material in the edge region of the deflection device 54 is avoided. Even simpler forms of the deflection device 54 are possible. In a very simple embodiment, the separating web 62 is extended upwards to the dashed auxiliary line L1 and the onflowing material melts M1, M2 are stopped and deflected directly by the lateral surfaces, which may be beveled or have a concave curve. Another simple embodiment provides that the surfaces 55 are inclined, flat surfaces or concavely curved surfaces, which deflect the melts M1 , M2 to the separating web 62 . According to the two aforementioned simple embodiments, the separate flow insert 68 can be omitted. The deflection unit 54 is then only arranged on the distributor ring 52 and the rings 16a to 16d.

the 15 until 17 show further configurations of preforms comprising biaxial, monoaxial and multiaxial layers. 15 shows a single-layer preform V8 with a symmetrical distribution of the different materials M1, M2. By appropriately defining the deflection positions Z1 and Z2 and their arrangement of deflection units 54 in the biaxial distributor ring 52, 80, the angle range for the material M2 can be changed, for example it can be smaller or larger than 180°.

16 shows a two-layer preform V9, whose outer layer S2, seen in the circumferential direction, contains two different materials M1, M2 in different hollow cylinder segments. The inner layer S1 is monoaxial, to which extrusion material M3 is supplied via two feeds E3 and E4.

A major application for extrusion of the present invention is the manufacture of at least one biaxial layer in a preform. It is also possible to carry out extrusion along more than two axes according to the principle described.

17 shows an example with three axes based on a cross section through the preform V10 or its coaxial equivalent Arrangement of material melts in cross-section in the lowest cylinder ring (cylinder ring 90 in 6 ). The inner layer S1 is a monoaxial layer of material M0 and is fed from an extruder as feed E0. The outer layer S2 is a triaxial layer with the different material M1, M2 and M3 fed from feeds E1, E2 and E3. The boundary surfaces G1, G2, G3 result at corresponding deflection positions Z1, Z2 and Z3 in the extrusion head. At these deflection positions Z1, Z2 and Z3, deflection units are arranged in the associated multi-axial distribution ring, which forward the material melts flowing towards one another downwards separately from one another. According to this principle, multi-axis preforms can be produced in a single extrusion head.

The example after 17 can be combined with the other examples described for preforms. In one or more biaxial distribution rings, three or more deflection devices can be present at corresponding deflection positions, so that the layer produced by the respective distribution ring has more than two different material melts.

Numerous variations of the illustrated embodiments are possible. In 6 two biaxial distributor rings and one monoaxial distributor ring are shown. Further distribution rings can also be added, e.g. also for three- or multi-axial extrusion, as in 17 shown. Distribution rings can also be fitted using material melts of different thicknesses in one layer, as shown in 7b is shown. Furthermore, the extrusion head can contain distribution rings, with the help of which angle ranges deviating from 180° for different materials are present in one layer of the preform, as is shown in FIGS 15 and 16 is shown.

Reference List

K1, K2

piston rods

IF1, IF2

feed opening

6

quill

8th

storage jacket

10

coextrusion head

12

common flow channel

14

ring buffer space

15

lower position of the annular piston

16

ring piston

16a

cone part

16b

top ring

16c

middle ring

16d

lower ring

18

output ring channel

20

die gap

22

cylinder ring

26, 28

distribution ring

Z1-Z3

deflection positions

30

estuary

32

expansion site

34

common cylinder ring

50

biaxial extrusion head

51

gap width

52

first distribution ring; biaxial distribution ring

53

side walls

54

deflection unit

54a

upper part

54b

lower part

55

Surface

56, 57

feed openings

58.59

flow channels

60

upper truncated cone canal

61

bottom edge

62

divider

63

end of the divider

64

upper cylinder ring

66

first mouth

68

upper annular flow insert

70

another distribution ring

72

middle truncated canal

73

middle cylinder ring

74

lower mouth

76

second flow insert

80

lower distribution ring

81

third truncated canal

82.83

feed openings

84

third deflection unit

84a

upper part

84b

lower part

86

third divider

88

lower flow insert

90

lower common cylinder ring

M1- M6

material melting; material

S1, S2, S3

layers

P1- P4

directional arrows

V1-V10

preform

L1

auxiliary line

QUOTES INCLUDED IN DESCRIPTION

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

Patent Literature Cited

• WO 2005097462 A1 [0002, 0013, 0029, 0033]

Claims (20)

Device for producing an at least one-layer extruded tubular preform (V2-V10) made of thermoplastic material, with an extrusion head (50) with at least one first distributor ring (52) arranged substantially coaxially around a sleeve (6) in an annular piston (16) that can be moved back and forth along the sleeve (6), which has at least two downwardly open flow channels (58, 59), which are each fed via an inflow opening (56, 57) with material melts (M1, M2), which are distributed in a ring in the flow channels (58, 59) and downward in a discharge ring (60) and into a common flow channel (12) and flow from there into a ring storage space (14) between the sleeve (6) and a storage jacket (8), and with an annular output channel (18) adjoining the annular storage space (14) with a lockable annular nozzle gap (20) from which the preform (V2-V10) is ejected, wherein a deflection unit (54) is arranged in the first distributor ring (52) for each material melt (M1, M2) at predetermined deflection positions (Z1, Z2, Z3), which prevent the material melts (M1, M2) flowing toward one another from spreading horizontally in the respective flow channel (58, 59) and deflect the material melts (M1, M2) downwards and bring them together at the lower end (63) of the deflection unit (54). device after claim 1 , characterized in that the deflection unit (54) has a separating web (62) which is guided with its end (63) downwards at least to an opening point (66, 72) for further material melts (M3-M6). device after claim 2 , characterized in that the separating web (62) is guided downwards with its end (63) at least close to the common flow channel (12) or projects into it. Device according to one of claims 2 until 4 , characterized in that the width of the separating web (62) tapers downwards, preferably from 8 mm to 2 mm. Device according to one of claims 2 until 4 , characterized in that the deflection unit (54) has an upper part (54a) which has an inwardly concavely curved surface (55, 53) on each side of the inflowing material melts (M1, M2) which points in the direction of the discharge ring (60) tapers to the separating web (62), at the end (63) of which the two material melts meet and continue to flow downwards. device after claim 5 , characterized in that below the first distributor ring (52) is arranged an annular flow insert (68) which carries a lower part (54b) of the deflection unit (54), the lower part (54b) having two side walls (53) which flush with the concave surfaces (55, 53) of the upper part (54a) and taper downwards in the direction of the flow ring (60) to the separating web (62). Device according to one of the preceding claims, characterized in that the drainage ring is designed as a truncated cone channel (60). Device according to one of the preceding claims, characterized in that a common cylinder ring (90) is arranged downstream in front of the common flow channel (12). Device according to one of the preceding claims, characterized in that the first distribution ring (52) is divided into several sectors (52a, 52b, 52c, 52d), there being one sector (52b, 52d) for each material melt (M1, M2). Having the deflection unit (54), the sectors on the circumference of the distributor ring (52) can be arranged differently in order to vary the angular range for the deflection positions (Z1, Z2). device after claim 9 , characterized in that the flow insert (68) is divided into sectors corresponding to the sectors of the first distributor ring (52). Device according to one of the preceding claims, characterized in that at least one further distributor ring (70, 80) is arranged coaxially to the first distributor ring (52), to which another material melt (M3) is supplied, which is distributed in a ring shape all around in the associated discharge ring (60). and fed down the common flow channel (12) in which they are received in coaxial juxtaposition with the material melts (M1, M2) from the first distribution ring (52). Device according to one of the preceding claims, characterized in that the deflection positions (Z1, Z2) have an angular spacing in the distributor ring (52) of 180°. Device according to one of the preceding claims, characterized in that the first distributor ring (52) contains deflection units (54) at more than two deflection positions (Z1, Z2, Z3), which direct the material melts (M1, M2, M3) flowing towards one another downwards. Device according to one of the preceding claims, characterized in that the material melts (M1, M2) differ in their mechanical and/or electrical properties. Device according to one of the preceding claims, characterized in that the material melts (M1, M2) differ in their color properties. Method for producing an at least one-layer tubular preform (V2-V10) made of thermoplastic material, which is extruded from an extrusion head (50), which contains at least one first distributor ring (52) which can be moved back and forth along a quill (6) and has at least two flow channels (58, 59) open at the bottom, which are each fed with molten material (M1, M2) via an inflow opening (56, 57). distributed annularly in the flow channels (58, 59) and flow downwards into a discharge ring (60) and into a common flow channel (12) and from there into a ring storage space (14) between the quill (6) and a storage jacket ( 8) arrive, wherein a deflection unit (54) is arranged in the first distributor ring (52) for each material melt (M1, M2) at predetermined deflection positions (Z1, Z2, Z3), which prevents the material melts (M1, M2) flowing towards one another from spreading horizontally in the respective flow channel (58, 59) and deflects the material melts (M1, M2) downwards and brings them together at the lower end (63) of the deflection unit (54), the preform (V2-V10) being ejected from an annular discharge channel (18) which adjoins the annular storage space (14) and has a lockable annular nozzle gap (20). Method according to one of the preceding claims, characterized in that a further material melt (M3) is fed to at least one further distributor ring (70, 80), which is distributed in a ring shape all around in a discharge ring (60) and a ring-shaped common flow channel (12) which widens in a funnel shape. in which it is received in coaxial juxtaposition with the material melts from the first distribution ring (52). Method according to one of the preceding claims, characterized in that the material melts (M1, M2) differ in their mechanical and/or electrical properties. Method according to one of the preceding claims, characterized in that the material melts (M1, M2) differ in their color properties. Method for producing a plastic component in the blow molding process, in which a in a device according to one of Claims 1 until 15 produced parison is fed to a blow mold.

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