DE202021104605U1 - Device for biaxial plastic extrusion - Google Patents

Abstract

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 essentially coaxially around a quill (6) in an annular piston (6) that can be reciprocated along the quill (6). 16) arranged first distributor ring (52), 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 in the flow channels (58, 59) are distributed in a ring and flow downward in a discharge ring (60) and in a common flow channel (12) and from there into a ring storage space (14) between the quill (6) and a storage jacket (8), and with one the annular storage space (14) adjoining the output annular channel (18) with a lockable annular nozzle gap (20) from which the preform (V2-V10) is ejected, in the first distributor ring (52) for Each material melt (M1, M2) is arranged at predetermined deflection positions (Z1, Z2, Z3) a deflection unit (54) which prevents the material melts (M1, M2) flowing towards one another from spreading horizontally in the respective flow channel (58, 59) and which Divert material melts (M1, M2) downwards and bring them together at the lower end (63) of the deflection unit (54).

Description

The invention relates to a device for producing an at least one-layer extruded tubular preform from thermoplastic material, preferably polyethylene (PE).

From the WO 2005/097462 A1 an extrusion system is known, the structure of which is further down in connection with 1 is explained in more detail. With this extrusion system, preforms with several coaxially arranged layers of different materials can be produced, each layer having the same plastic material as seen in the circumferential direction.

It is the object of the invention to provide a device for producing a tubular preform which, viewed in the circumferential direction of the preform, has different plastic materials.

This object is achieved for a device by the features of claim 1. Advantageous further developments are given 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 fed largely separately from one another into the ring storage space. Several material melts are ejected from this annular storage space as a preform, which, viewed in the circumferential direction, can have two or more plastic materials that 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 distributor rings can dispense different melts of material which form a hollow cylinder layer in the preform. This hollow cylinder layer is divided in its length so that an elongated 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, multi-axial) extrusion within a layer is that the materials used for 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. A bottom side of this product can have a different color than its top side. 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 multi-axial) 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 a further material melt is fed, which is distributed in a ring around the associated discharge ring and fed down to the common flow channel, in which it is mixed with the material melts from the first Distribution ring are added in coaxial juxtaposition. In this way a multiplicity of distributor rings of the type of the first distributor ring as well as of the type of the second distributor ring can be arranged in the extrusion head and a multiplicity of variations of abutting plastic materials can be realized in a preform.

A further advantageous embodiment provides that the distributor ring contains deflection units at more than two deflection positions, which deflect downwardly the material melts flowing towards one another. In this way, by extrusion in several axes, a preform can be produced which has several plastic materials within a single layer.

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

The present invention relates to a further development of one in WO 2005/097462 A1 described extrusion line. The content of this document is incorporated into the disclosure content of the present application. In the present 1 is a coextrusion head 10 based on the above WO 2005/097462 A1 partly shown in longitudinal section. It includes a storage jacket 8th , which has a ring memory space 14th surrounds, which receives the material melts to be ejected. The storage jacket 8th is connected to a housing, not shown. A material melt is via an inflow opening ZF1 a distribution ring 26th fed to an annular piston 16 heard. This ring piston 16 can be moved in its longitudinal axis and slides along a quill 6th and the storage jacket 8th . The annular piston 16 is connected to a hydraulic device (not shown) via piston rods K1 , K2 tied together. The same is true of the quill 6th connected at its upper end to a hydraulic device (not shown). The extrusion head is in operation 10 vertical with its longitudinal axis m on a flat base and the terms "above, below, horizontal, vertical, etc." are unambiguous and clear with regard to the function of the extrusion head for the present innovation.

The material melt is horizontal along the distribution ring 26th promoted and at the same time flows downwards along an annular truncated cone channel 40, which runs along a truncated cone jacket of the annular piston 16 is trained. The downward flowing material melt then enters a cylinder ring 22nd and from there to an outlet point 30th , where a second material melt opens. This second material melt is diametrically to the feed opening ZF1 arranged second feed opening ZF2 is supplied from there via an associated circulating distributor ring 28 distributed and reaches an annular second truncated cone channel 44. From there, the second material melt flows to the point of opening 30th .

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 runs as smoothly as possible and is not disturbed by eddies. To the muzzle 30th it is followed by a calming section, which acts as a common cylinder ring 34 is trained. This calming section ensures that after the unification of the material melts at the point of the mouth 30th a uniform flow of the two material melts results, whereby a smooth course of the cylinder jacket interface between the two material melts is generated. The two material melts then flow up to an expansion point 32 , where the two materials melt in a widening common flow channel 12th merge. This flow channel 12th has a funnel shape in cross section with lateral surfaces 36, 38 and is in the annular piston 16 ring-shaped.

The ring piston is at the beginning of the filling process 16 in its lower position, as shown schematically in dashed lines in connection with the reference number 15th is indicated. The funnel-shaped common flow channel 12th is with the two material melts from the previous production process for creating a tube-like preform V1 filled. As the two material melts continue to flow, the annular piston becomes 16 moved up. Due to the funnel shape of the common flow channel 12th and the further geometry for the material melt guide, the interface that forms between the two material melts remains largely smooth and is not swirled.

When the annular piston 16 has reached its upper working point, the quill becomes 6th moves downwards and opens an annular nozzle gap with its nozzle head 6a 20th so that with a downward movement of the annular piston 16 a tubular preform V1 is ejected with the interface between the two material melts. An output ring channel is provided to maintain the smooth course of the interface 18th in its geometry to the nozzle gap 20th tapered. When the ejection process is completed, the quill becomes 6th moves up again and closes the nozzle gap 20th , whereupon a new filling process for the ring memory space 14th begins.

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

3 shows above a single-layer biaxial preform produced according to the invention in an extrusion system V2 in cross section and in a perspective view. For the production of this preform V2 a feed E1 with a material melt is carried out at an associated feed opening in an extrusion head M1 and a feed E2 with one of M1 different material melt M2 . In the circumferential direction P2 seen, the shift continues S1 from the materials M1 and M2 together, which are largely sharply delimited from one another at interfaces G1. For example, the materials have M1 and M2 different colors, like this one in the 3 is indicated by hatching. The material melts M1 and M2 after being fed in via E1 or E2, as indicated by arrows, spread in the circumferential direction in corresponding flow channels (see 6th ) the end. Seen in the direction of extrusion, the preform settles V2 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 the simplified description, material melts are included below M1 , M2 , M3 ... as well as the corresponding materials available in the preform M1 , M2 , M3 ... designated.

4th shows a two-layer biaxial preform V3 , which has four feeds E1, E2, E3, E4 with three different material melts M1 , M2 and M3 is extruded. The outer layer S2 exists in the circumferential direction P2 seen from the different materials M1 , M2 . The inner layer S1 Although it is fed from two feeders E3 and E4, it is made of the same material M3 ; this layer S2 is thus monoaxial by definition.

5 shows another preform V4 , which has a biaxial structure and has three layers S1 , S2 and S3 includes. It is made up of feeds E1 to E6 with material melts M1 until M5 fed. The outer layer S3 is biaxial and contains the material extruded from feeds E1 and E2 M1 and M2 . The layer S2 is monoaxial and consists of the material all around without interruption M3 , which is extruded from the two opposite feeds E3 and E4. The innermost layer S1 is again biaxial and comprises the various materials M4 and M5 from feeders E5 and E6.

6th shows schematically an extrusion head 50 according to the invention for producing a multilayer biaxial and monoaxial preform. Features with features after 1 match are labeled the same. The annular piston 16 includes an upper cone part 16a , an upper ring 16b , a middle ring 16c and a lower ring 16d . The cone part 16a includes an upper biaxial first distribution ring 52 , in which on the circumference at two opposite deflection positions Z1 , Z2 (see. 8th and 9 ) one deflection unit each 54 is arranged. Over opposite feed openings 56 respectively. 57 becomes on both sides of the first distributor ring 52 a first material melt M1 or a second material melt M2 fed, each semicircular in two annular flow channels 58 , 59 distribute and from these downwardly open flow channels 58 , 59 into a drainage ring, which is an annular truncated cone channel 60 is trained to continue to flow. An upper part 54a the deflection unit 54 is in the distribution ring 52 arranged 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 the deflection unit 54 protrudes into the truncated cone canal 60 (and possibly further from there) and also there prevents the confluence of the material melts flowing towards one another from both sides M1 , M2 . The lower part 54b the deflection unit 54 opens into a divider 62 that is at least within a portion of the truncated cone channel 60 and optionally also the merging of the melts M1 , M2 prevented. The material melts M1 and M2 get into an upper cylinder ring 64 where they are at a muzzle 66 with further material melts are brought together.

The lower parts 54b of the two deflection units 54 are through an upper annular flow insert 68 held below the first distributor ring 52 is arranged. Distribution ring 52 and flow use 68 are separate components.

The annular piston 16 contains between its upper ring 16b and its middle ring 16c another distributor ring to form a monoaxial layer 70 . Such a distribution ring 70 is also called a monoaxial distributor ring. Its two feed openings for another material melt M3 are in the 6th not to see. Seen in the circumferential direction, they are each at a predetermined angle with respect to the feed openings 56 , 57 offset. The material melt M3 flows in a truncated cone canal 72 down to a point of mouth 66 where they melt in contact with the material M1 and M2 the inner layer of the biaxial preform to be manufactured. The layers of material flow from there M1 until M3 in the middle cylinder ring 73 whose ring diameter is larger than that of the upper cylinder ring 64 , down to a lower muzzle point 74 where a third layer, an outer biaxial layer, joins. For the further distribution ring 70 can be a second flow insert 76 to be available.

The ring piston also contains 16 a lower distribution ring 80 , which is analogous to the first distributor ring 52 is constructed, with feed openings 82 , 83 about a fourth material melt M4 or a fifth material melt M5 are fed. The material melts M4 , M5 get into a lower truncated cone canal 81 that is between the middle ring 16c and the lower ring 16d is trained. As can be seen in the section, the lower distributor ring also contains 80 at two specified deflection positions Z1 , Z2 (in 6th is only Z1 shown), with the deflection positions for the first distributor ring 52 match, one deflection unit each 84 , an upper part 84a and a lower part 84b that is in a divider 86 flows out. The location of the dividers 62 for the distribution rings 52 and 80 agrees with the deflection position Z1 match. The lower part 84b is through a lower annular flow insert 88 held.

After the muzzle 74 three adjacent coaxial layers flow S1 , S2 and S3 down into a third common cylinder ring 90 with a correspondingly enlarged ring diameter and from there into the common flow channel 12th and in the ring buffer space 14th (see. 1 ), from where a multilayer biaxial and monoaxial preform V5 is expelled. In this lowest common cylinder ring 90 all layers are arranged coaxially and have the same flow rate.

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

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

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

Another variant is the middle distributor ring 70 as a biaxial distributor ring analogous to the first distributor ring 52 to be designed with a corresponding drainage channel. The middle layer can then analogously S2 have two layers of material in the circumferential direction.

The embodiment according to 6th can be expanded with further distributor rings, which are used as biaxial distributor rings analogous to the first distributor ring 72 and / or as monoaxial distributor rings analogous to the further distributor ring 70 are constructed. By combining different biaxial distribution rings and monoaxial distribution rings, different types of preforms can be produced, 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 a different material M1 until M5 have, which in molten form via feeds E1 until E5 is fed in. At the deflection positions Z1 , Z2 arranged deflection units 54 with associated dividers 62 there will be a mixing of the material melts M1 until M5 prevented. As in 7b As can be seen, the thickness of the layer H1 is greater than the thickness of the individual 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 in the radial direction in the common lowermost cylinder ring 90 is constant. For the production of the preform V6 five biaxial distributor rings are required.

7c shows a preform V7, similar to FIG V6 , but also with an inner circumferential monoaxial layer S0 with material M0. This layer S0 can be produced conventionally, for example as mentioned in US Pat WO 2005/097462 A1 is described. It can also be produced with the aid of a biaxial distributor ring in that the same material is fed in at its two inlets, with both material melts, which are semicircular in cross section, reuniting in the flow path downwards.

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

9 shows a top view of the first distributor ring 52 . At the deflection positions Z1 , Z2 are the deflection units 54 arranged that the horizontal flow of the material melt M1 respectively. M2 impede. It is advantageous if the distributor 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 respectively. M2 ; 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 attached to separation surfaces Ta, Ta; Tb, Tb; Tc, Tc; Td, Td are separable from one another. The associated annular flow insert is also in the same way 68 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 each encompass a semicircle in the preform. According to 11 the different segments are put together differently. The segment 52b with its one separating surface Tb is assigned to the feed E2, likewise the segment 52d with its separating surface Td. The segment 52a lies with its one separating surface Ta at the level of the feed E1, as is the segment 52c with Tc. As can be seen, the deflection devices close 54 of segments 52b and 52d and the associated deflection positions Z1 and Z2 now an angular range of 90 ° for the material M2 and for the material M1 of 270 °. As a result of the segmentation carried out, it is therefore possible to vary angular ranges for materials during biaxial extrusion without extensive intervention in the machine structure being necessary. According to the principle described, a subdivision into more than four segments (for example eight segments) can be advantageous in order to provide the angular ranges for two deflection positions Z1 , Z2 or to vary for more than two deflection positions.

12th shows schematically a vertical section through the deflection unit 54 and the biaxial manifold 52 . The upper part 54a is in the deflection unit 54 formed and has on each side of the inflowing material melt M1 , M2 an inwardly concave surface 55 on (in 12th the middle arc line is drawn), which is in the direction of the truncated cone canal 60 pointed to the separating web 62 at the end of it 63 the two material melts M1 , M2 butt against each other and continue to flow downwards largely separated from each other. The lower part 54b the deflection unit 54 is on the annular flow insert 68 attached and its side walls 53 , which are also curved concavely inward, close to the deflection surfaces 55 smooth on. This results in a largely eddy-free deflection of the melt M1 , M2 at the deflection positions Z1 , Z2 guaranteed. The length of the narrow divider 62 is chosen so that a sufficiently sharp separation when the melt continues to flow M1 , M2 after the end 63 is guaranteed. It can be up to the height of the respective discharge point 66 or 74 (please refer 6th ) be performed. The further this divider 62 with its end 63 down to the respective mouths 66 , 74 and, if necessary, is led beyond this, the sharper the separation is. Preferably the end protrudes 63 of the separator 62 down to the lowest common name cylinder ring (in 6th the cylinder ring 90 ), where all material melts are arranged coaxially are before they enter the common funnel-shaped flow channel 12th flow on. The separator tapers here 62 from 8 mm to 2 mm, for example.

The formation of the deflection surfaces 55 and the side walls 53 are in the shape of the upper portion of a heart, as shown in 12th is sketched below with solid lines. To that extent is the curvature of the deflection unit 54 in their upper part 54a and its lower part 54b (without divider 62 ) heart-shaped.

13th shows a longitudinal section through the deflection unit 54 with upper part 54a , lower part 54b and the jetty 62 that is in the first truncated cone canal 68 protrudes. The upper part 54a is in the first distribution ring 52 between the two flow channels 58 , 59 educated. These flow channels 58 , 59 are open at the bottom and have a gap width 51 that is between a bottom edge 61 and the upper ring part 16b results. The lower part 54b is on the flow insert 68 attached and closes up on the upper part 54a and down to the divider 62 on, the one in the truncated cone canal 60 runs.

14th shows a cross section through the deflection unit 54 seen from above. The material melts M1 and M2 are through the deflection unit 54 down into the first truncated cone canal 60 diverted.

the 12th until 14th show a preferred embodiment of the deflection unit 54 . It has the technical advantage that the incoming material melts M1 , M2 Are deflected flow-favorably and a disruptive deposition of plastic material in the edge area of the deflection device 54 is avoided. There are even simpler forms of the deflection device 54 possible. In a very simple embodiment, the separating web is 62 up to the dashed auxiliary line L1 extended and the incoming 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 inclined, flat surfaces or concavely curved surfaces are which the melts M1 , M2 to the divider 62 redirect. According to the two aforementioned simple embodiments, the separate flow insert 68 omitted. The deflection unit 54 is then only on the distributor ring 52 and the rings 16a until 16d arranged.

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

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

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

17th shows an example with three axes based on a cross section through the preform V10 or its equivalent to the coaxial arrangement of material melts in cross section in the lowest cylinder ring (cylinder ring 90 in 6th ). The inner layer S1 is a monoaxial layer with the 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 feeders 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 distributor ring, which divert 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 17th can be combined with the other examples described for preforms. In one or more biaxial distributor 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 exemplary embodiments shown are possible. In 6th two biaxial distribution rings and one monoaxial distribution ring are shown. Further distribution rings can also be added, for example also for three- or multi-axial extrusion, as in FIG 17th shown. Distribution rings using melts of material of different thicknesses in one layer can also be incorporated, as shown in FIG 7b is shown. Furthermore, the extrusion head can contain distribution rings, with their Help in a layer of the preform deviating from 180 ° angular ranges for different materials are available, as in the 15th and 16 is shown.

List of reference symbols

K1, K2

Piston rods

ZF1, ZF2

Feed opening

6th

Quill

8th

Storage jacket

10

Coextrusion head

12th

common flow channel

14th

Ring storage space

15th

lower position of the annular piston

16

Ring piston

16a

Cone part

16b

upper ring

16c

middle ring

16d

lower ring

18th

Output ring channel

20th

Nozzle gap

22nd

Cylinder ring

26, 28

Distribution ring

Z1- Z3

Deflection positions

30th

Mouth point

32

Extension point

34

common cylinder ring

50

biaxial extrusion head

51

Gap width

52

first distribution ring; biaxial distributor ring

53

side walls

54

Deflection unit

54a

upper part

54b

lower part

55

area

56, 57

Feed openings

58, 59

Flow channels

60

upper truncated cone canal

61

Lower edge

62

Divider

63

End of the separator

64

upper cylinder ring

66

first muzzle

68

upper annular flow insert

70

another distributor ring

72

middle truncated cone canal

73

middle cylinder ring

74

lower muzzle

76

second flow insert

80

lower distribution ring

81

third truncated cone canal

82, 83

Feed openings

84

third deflection unit

84a

upper part

84b

lower part

86

third separator

88

lower flow insert

90

lower common cylinder ring

M1-M6

Material melting; material

S1, S2, S3

layers

P1-P4

Direction arrows

V1-V10

Preform

L1

Auxiliary line

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed 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 2005/097462 A1 [0002, 0011, 0027, 0031]

Claims (15)

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 essentially coaxially around a quill (6) in an annular piston (16) movable to and fro along the quill (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 the flow channels (58, 59) in a ring shape and downward in a discharge ring (60) and a common flow channel (12) flow and from there into an annular storage space (14) between the quill (6) and a storage jacket (8), and with an output ring channel (18) adjoining the ring storage space (14) with a lockable ring-shaped nozzle gap (20) from which the preform (V2-V10) is ejected, a deflection unit (54) being arranged in the first distribution ring (52) for each material melt (M1, M2) at predetermined deflection positions (Z1, Z2, Z3), which prevent the material melts (M1, M2) flowing towards each other 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 according to 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 according to Claim 2 , characterized in that the separating web (62) is guided downwards with its end (63) at least as far as the vicinity of the common flow channel (12) or protrudes into it. Device according to one of the Claims 2 until 3 , characterized in that the width of the separating web (62) tapers downwards, preferably from 8 mm to up to 2 mm. Device according to one of the Claims 2 until 4th , characterized in that the deflection unit (54) has an upper part (54a) which on each side of the inflowing material melts (M1, M2) has an inwardly concavely curved surface (55, 53) which extends in the direction of the discharge ring (60) tapers to the separating web (62), at the end (63) of which the two material melts abut one another and continue to flow downwards. Device according to Claim 5 , characterized in that below the first distributor ring (52) an annular flow insert (68) is arranged which carries a lower part (54b) of the deflection unit (54), the lower part (54b) having two side walls (53) which align with the concavely curved surfaces (55, 53) of the upper part (54a) and taper downwards in the direction of the discharge ring (60) towards the separating web (62). Device according to one of the preceding claims, characterized in that the discharge 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 distributor ring (52) is divided into several sectors (52a, 52b, 52c, 52d), one sector (52b, 52d) being present for each material melt (M1, M2) , which has the deflection unit (54), the sectors in 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 according to 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 a further material melt (M3) is fed, which is distributed in a ring all around in the associated discharge ring (60) and are fed down to the common flow channel (12) in which they are received in coaxial juxtaposition with the material melts (M1, M2) from the first distributor 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 deflect 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.

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