CARTRIDGE

Description

Field of the invention

[0001] The invention relates to a cartridge made of a plastic material for use in a commercially available cartridge press according to the preamble of claim 1, a set of such a cartridge with a piston and a nozzle and a method for producing such a cartridge according to the preamble of claim 19. State of the art

[0002] Cartridges for filling, for example, sanitary silicone or adhesive have long been known in the art. The cartridge has a first and a second end. A screw extension with an external thread and a cap is formed at the first end. The second end is open and therefore has a filling opening. A piston is inserted into the filling opening after the product has been filled.

[0003] To extrude the product, the cap is cut off and a nozzle is screwed onto the extension. The cartridge is inserted into a cartridge press, and the cartridge is ready for use. To ensure the cartridge fits into a standard cartridge press, its dimensions are more or less standardized.

[0004] The cartridge is injection-molded in expensive tools. Because injection-molded cartridges are single-layer, meaning the wall thickness consists of a single layer throughout, the choice of material and wall thickness must ensure the longest possible product durability. As a result, such a cartridge generally exhibits good barrier properties at the expense of increased material usage. Typically, cartridges with very good barrier properties are injection-molded from polyamide, or the wall thickness is increased when using polyethylene or polypropylene or similar materials to achieve the desired barrier effect.

[0005] Because injection-molded cartridges cannot be completely emptied, used cartridges must be collected and disposed of separately. Recycling them is virtually impossible. The typical contents of cartridges are silicones and adhesives, and the residues of these contents represent contamination, making economically viable recycling of the plastic used in the cartridge virtually impossible. Market demand requires a cartridge to be white. Since recycled plastic material, even from sources other than cartridges, always contains contamination, it is virtually impossible to produce a cartridge from recycled material in white.

[0006] US 5,593,066 discloses a coextrusion blow-molded cartridge in which polyethylene, polypropylene, etc. is coextruded with a material forming a barrier layer. Object of the invention

[0007] The disadvantages of the described prior art give rise to the task of creating a generic cartridge in the production of which recycled plastic material can be processed.

[0008] A further task is to demonstrate a cartridge that can be manufactured using the least possible amount of material, yet still has sufficient mechanical stability and the product in the cartridge can be stored for a long time. Description

[0009] The stated problem is solved with a cartridge made of a plastic material for use in a commercially available cartridge press by the features stated in the characterizing portion of patent claim 1. Further developments and / or advantageous embodiments are the subject of the dependent patent claims.

[0010] The invention is preferably characterized in that the second layer consists of a recycled plastic. This layer combination has the advantage that, on the one hand, plastic material from recycled cartridges can be reprocessed as a second layer, and, on the other hand, the first layer meets consumer requirements regarding the appearance, particularly the color of the cartridge, which requirements cannot be met by the second layer. For example, producing a recycled plastic in white is only possible with great effort, since the reprocessed plastic inevitably contains other color particles.

[0011] The invention is additionally characterized in that the cartridge has a third layer which is made of a new plastic and the second layer is arranged between the first and the third layer. Since recycled plastic usually has a somewhat rougher surface after extrusion, this together with the piston cannot provide an adequate seal for the interior which is filled with product. Since new plastic usually has a smoother surface, the embedding of the second layer between the first and the third layer is necessary for a reliable seal of the interior of the cartridge. Since the third layer is primarily intended to provide a smooth inner wall of the casing, the third layer can be comparatively thin.

[0012] It has proven useful to make the first layer of a new plastic, preferably white. This allows a wide range of consumer requirements regarding the appearance of a cartridge to be met, while still allowing part of the cartridge to be made of recycled plastic.

[0013] The invention is also preferably characterized in that the cartridge has a barrier layer arranged between a first and second adhesive layer, and the barrier layer together with the adhesive layers is arranged within the first layer. This allows a reliable barrier effect of the cartridge to be created, which at least corresponds to the barrier properties of an injection-molded cartridge. Products filled in the cartridge according to the invention therefore have a long shelf life. Furthermore, for cartridges for filling materials that are shielded from the ambient air with a barrier layer, for example for filling materials such as adhesives or sealants, the sum of the layer thicknesses in cartridges according to the invention is smaller than the wall thickness of a conventional injection-molded cartridge, thereby enabling material savings.

[0014] The barrier layer, including the adhesive layers, is conveniently positioned between the first and second layers. In this arrangement, the barrier layer is particularly effective because it is preferably positioned closer to the outer wall to achieve the maximum gas barrier. This is because permeable media must first overcome a thicker plastic layer before reaching the barrier layer from the inside of the container to the outside.

[0015] It has proven advantageous for the barrier layer to be made of ethylene-vinyl alcohol copolymer (EVOH). Since EVOH has very good oxygen barrier properties, the product is reliably protected from contact with the oxygen present in the air. Moisture cannot escape from the product. This ensures a long shelf life in the cartridge, especially if the cartridge is unopened. Alternatively, polyamide can also be used as a barrier.

[0016] In a further preferred embodiment of the invention, the first layer and the third layer each make up a maximum of 20 wt%, preferably 10 wt%, of the cartridge weight, and the third layer makes up to 80 wt% of the cartridge weight. This weight distribution of the layers allows the second recycled layer to account for the largest possible proportion of the used plastic, while the first and third layers made of virgin plastic only account for the proportion necessary for the functional requirements.

[0017] In a further preferred embodiment of the invention, the wall thickness of the shell, which results from the sum of the layer thicknesses, is preferably between 0.7 mm and 2.1 mm, and preferably between 0.9 mm and 1.5 mm. Comparing conventional cartridges for a specific filling material with enhanced barrier properties with a cartridge according to the invention intended for the same filling material, this wall thickness range of the cartridge according to the invention is smaller than the wall thickness of a conventional, commercially available injection-molded cartridge. Accordingly, the material used is cost-effective, and a significant portion of it consists of a less expensive recycled plastic.

[0018] Conveniently, the removal element is an extension with an external thread and a cuttable cap, with the cap being held at the first end by a retaining strap. This ensures that the cap is permanently attached to the casing after cutting and is disposed of together with the casing.

[0019] In a further preferred embodiment of the invention, the dispensing element is a nozzle that tapers from the first end and is closed at its free end. Because the nozzle is molded integrally with the casing, the user does not need to screw on a separate nozzle during initial use; instead, the cartridge is immediately ready for use after cutting off the nozzle tip. The blow-molded nozzle can have various lengths, depending on the length of the negative mold of the nozzle in the tool.

[0020] Conveniently, a plurality of cutting lines are provided on the nozzle, arranged along its length, along which the nozzle can be cut off. This allows a product strand with a specific diameter to be extruded from the cartridge, depending on the selected cutting line at which the nozzle tip is cut off. The corresponding inner diameter of the nozzle can be indicated on the cutting lines to improve the user-friendliness of the cartridge.

[0021] In a particularly preferred embodiment of the invention, the nozzle has a connecting piece with an external thread at its end facing the first end. This allows the nozzle to be cut off above the connecting piece if product has dried into it. A separate nozzle can then be screwed onto the connecting piece.

[0022] It is advantageous to incorporate a transparent strip along the length of the shell to monitor the product fill level. This strip can be easily incorporated during the extrusion of the layers. The user can see the product height and the position of the piston on the shell surface at any time.

[0023] In a further particularly preferred embodiment of the invention, a partial region of the shoulder of a cartridge precursor formed from a tube is irreversibly displaced into the cartridge interior in such a way that at least in a partial region the first end is undercut on the cartridge, wherein the edge region of the undercut first end is formed from a partial region of the shoulder or from a partial region of the shoulder and the adjoining jacket of the cartridge precursor by bending and / or upsetting. Compared to a commercially available injection-molded cartridge, the present coextruded cartridge achieves the necessary barrier properties for long product storage life with less material usage. However, this can reduce the stability of the cartridge, resulting in, for example, a failure of a drop test.Moving the shoulder into the cartridge interior significantly increases the mechanical stability of the first end. This is due to the doubling of the jacket wall at the first end. Stability can be further increased by welding or gluing the two adjacent jacket walls together. Mechanical stability can also be increased by moving or bending the bottom section of the jacket into the cartridge interior, in addition to the shoulder area. This gives the "double wall" an increased height or surface area.

[0024] In another particularly preferred embodiment of the invention, the open end has a rim formed by cutting off an end piece of the cartridge. Cutting off the rim provides a cleanly defined edge, which can be made even more precise by trimming. A further advantage of removing the rim is that the jacket can be of any length, depending on the length of the cut-off rim. This allows cartridges with different volumes to be produced easily without having to change the tool. However, the cartridge must be shortened sufficiently to be insertable into a cartridge press.

[0025] The rim conveniently has a circumferential step. This step can be created with a rotary cutter and has the advantage that it can serve as an adhesive surface for sealing the open second end. The seal can be made of aluminum foil, for example, and extends the product's shelf life before first opening, as the cartridge is doubly sealed at the open end by the piston and the seal.

[0026] The plastic used for the first and second layers is preferably HDPE or extrudable PET, which are easy to coextrude and have good barrier properties. The extrudable PET can be, for example, x-PET or g-PET.

[0027] A further aspect of the invention relates to a set comprising a cartridge as described above, a piston that can be inserted into the second end after filling the cartridge, and a nozzle with an internal thread that can be screwed onto the external thread of the dispensing element. This allows the cartridge to be reliably sealed by the manufacturer and can be reused by the user.

[0028] A further aspect of the invention relates to a method for producing the cartridge described above by coextrusion blow molding, which also includes a recycling process for empty cartridges.

[0029] The invention is characterized by the fact that a new plastic and a recycled plastic are melted and coextruded into a first and second layer. This allows the advantages of the first and second layers to be combined in a compound material.

[0030] The inventive method is further characterized by the fact that another novel plastic is coextruded in a third layer, with the second layer being extruded between the first and third layers. This allows the creation of an inner surface against which the piston can slide easily and reliably, forming a seal.

[0031] In a particularly preferred embodiment of the invention, the recycled plastic originates from a recycling stream of completely emptied cartridges produced by coextrusion blow molding. This allows the used cartridges to be ideally recycled, creating a closed recycling stream.

[0032] Advantageously, the recycled plastic is freed of product residues and fed to the corresponding extruder as flakes or granules for the production of the second layer. This allows for the use of known and technically mature recycling processes to reuse the empty cartridges for the production of the second layer.

[0033] A plastic with barrier properties, preferably an ethylene-vinyl alcohol copolymer, is expediently coextruded as a barrier layer, with the barrier layer being coextruded between a first and second adhesive layer. This prevents the product from reacting with atmospheric oxygen and drying out, allowing it to be stored for a long time. The adhesive layers firmly embed the barrier layer in the layered composite.

[0034] In another particularly preferred embodiment of the invention, a cartridge precursor is formed by providing the tube in the blow mold with a first closed end having a shoulder and a second open end, inflating the cartridge over the second end, and forming a removal element at the first end. This allows all elements of the cartridge to be formed in the blow mold. The bottom does not need to be closed by squeezing, as is usual with EBM processes; instead, the second end can remain open in an elegant manner, as it is closed by the piston after product filling.

[0035] The method according to the invention is also characterized in that a slide of the blow mold is displaced from a first position, in which the first end of the cartridge precursor was formed, to a second position, in which at least a partial region of the first end is irreversibly displaced into the cartridge interior such that an undercut first end is formed on the cartridge in at least a partial region, wherein the edge region of the undercut first end is formed from a partial region of the shoulder or from a partial region of the shoulder and the adjoining jacket of the cartridge precursor by bending and / or upsetting. This method step allows the mechanical stability of the cartridge to be improved, as already explained in detail above.

[0036] The invention is also characterized by the fact that, to form a defined edge at the second end, an end piece of the cartridge is cut off, which simultaneously determines the length of the cartridge. The edge, which cannot be precisely formed during extrusion blow molding, is thus given a precise shape. At the same time, the selected length of the cartridge allows the filling volume of the cartridge to be flexibly determined and is independent of the shape of the tool. However, it is expedient to select the length of the sleeve such that the cartridge fits into a commercially available cartridge press.

[0037] In another particularly preferred embodiment of the invention, the cut-off end piece is fed into the recycling stream. This effectively integrates the so-called "lost" end piece into the cartridge manufacturing process.

[0038] Further advantages and features will become apparent from the following description of several embodiments of the invention with reference to the schematic representations. These are not to scale: Figure 1: a perspective view of a cartridge with 3 layers, wherein the middle layer is extruded from recycled cartridge material; Figure 2: a perspective view of a cartridge, wherein the 3 layers are made of Figure 1are supplemented by a barrier layer and two adhesive layers; Figure 3: the first end of a cartridge with a cut-off cap, which is held to the cartridge with a retaining strap; Figure 4: a cartridge with a nozzle, which nozzle is formed integrally with the cartridge; Figure 5: a cartridge with a transparent strip for fill level control; Figure 6: a detailed view of the edge of the open cartridge end in a partial sectional view in a first embodiment; Figure 7: a detailed view of the edge of the open cartridge end in a partial sectional view in a second embodiment and a piston for insertion into the open cartridge end; Figure 8: the open cartridge end closed by a sealing element; Figure 9: a sectional view of a cartridge precursor formed in a blow mold;Figure 10: a sectional view of the cartridge in an embodiment in which the first end is formed with a slide; Figure 11: a sectional view of the cartridge precursor; and Figure 12: a sectional view of the cartridge; Figure 10 after demoulding from the blow mould.

[0039] In the Figures 1 to 8 A cartridge or details of the cartridge are shown, designated overall by reference numeral 11. The cartridge 11 has a cylindrical shell 13 and a discharge element, which may be an extension 15 or a nozzle 17. The cartridge is coextrusion blow-molded to form a plurality of layers.

[0040] The casing 13 has a first closed end 19 with a shoulder 20 and a second open end 21. A product, for example silicone, an acrylic sealant or an adhesive, is filled into the cartridge 11 through the second end 21 or a filling opening 22 formed by the second end 21. After the product has been filled, the second end 21 is closed with a piston 23 ( Figure 7 ). The cartridge 11 is dimensioned such that it can be inserted into a standard cartridge press. After opening the dispensing element, the piston can be pressed into the casing 13 with the cartridge press to extrude the product in a measured amount from the cartridge 11.

[0041] The cartridge 11 has at least a first outer layer 25 and a second inner layer 27. The first layer 25 is coextruded from a new plastic, preferably "virgin" HDPE. The second layer 27 is coextruded from a recycled plastic. The recycled plastic is preferably made from completely emptied and disposed of cartridges 11 according to the invention. However, another recycled plastic, for example rHDPE, can also be used. The second layer 27 is covered by the first layer 25, since the predominant market needs require a cartridge to be white. This color requirement can only be met with reasonable effort by a new plastic, since recycled plastic always contains color-effective impurities.

[0042] In the Figure 1A first embodiment with three coextruded layers is shown. The second layer 27 is arranged between the first layer 25 and a third layer 29 made of virgin plastic. The third layer 29 is provided because recycled plastic has a rougher surface than virgin plastic. The second layer 27 would therefore be unsuitable for reliably sealing the jacket 13 against the piston 23.

[0043] In the Figure 2An embodiment with an additional barrier layer 31 is shown. The barrier layer 31 is embedded between a first and second adhesive layer 33, 35. The adhesive layers 33, 35 are necessary to reliably bond the barrier layer to the first and second layers 25, 27. The barrier layer 31 preferably consists of an ethylene-vinyl alcohol copolymer (EVOH) or, alternatively, of polyamide (PA). This provides particularly good protection against drying out of the product filled into the cartridge over a long period of time.

[0044] The sum of the layer thicknesses results in the wall thickness of the shell, which is preferably between 0.7 and 2.1 mm. Depending on the barrier properties, this wall thickness can be considerably thinner than that of injection-molded cartridges. If EVOH or PA is used as the barrier, it should be noted that the density of these materials is 1.2-1.3 g / cm3, while HDPE, for example, has a density of 0.95 g / cm3. Thus, the weight savings from a 50% reduction in wall thickness for such an inventive cartridge are only approximately 20-30% compared to conventional cartridges.

[0045] In the Figure 3It is shown that the removal element is the extension 15 with an external thread 37. The extension 15 also has a cuttable cap 39. Before the first use of the cartridge 11, the cap 39 is cut off with a blade so that product can be pressed out of the cartridge 11. To prevent the cut-off cap 39 from being disposed of separately, it is held at the first end 19 with a retaining band 41. The retaining band 41 is arranged at the first end 19 in such a way that it does not obstruct a separate nozzle, which is screwed onto the extension 15.

[0046] In the Figure 4an embodiment is shown in which the nozzle 17 is formed integrally with the casing 13. The nozzle 17 tapers away from the first end 19 and its free end is closed so that the cartridge 11 is completely closed after filling with product and inserting the piston 23. This embodiment is particularly practical because no separate nozzle needs to be screwed on when the cartridge 11 is used for the first time. Instead, one of the cutting lines 43 on the nozzle 17 is cut off. The cutting lines 17 are arranged along the length of the nozzle. One of the cutting lines is to be selected depending on how large the inner diameter of the nozzle 17 is to be. The corresponding inner diameter of the nozzle 17 can be printed on the cutting lines 43.

[0047] At the end of the nozzle 17 facing the first end 19, a connecting piece 45 with an external thread 37 is formed. After the first use of the cartridge 11, the nozzle 17 can be cut off at the transition to the connecting piece 45. For further use of the cartridge 11, a separate nozzle can be screwed onto the connecting piece 45.

[0048] In the Figure 5 It is shown that a transparent strip 47 is incorporated in the longitudinal direction of the casing 13 for monitoring the product level. This allows a visual check of the location of the piston 23 on the inside of the casing.

[0049] In the blow mold, the cartridge 11 is inflated over the open end 21. To ensure that the jacket has a defined edge 49 at the open end 21 after inflation, an end piece of the jacket 13 is cut off. This not only gives the jacket 13 a defined finish, but also a specific length. The length of the jacket 13 and the associated filling volume of the cartridge 11 can therefore be manufactured very easily and flexibly by selecting a specific length for the end piece to be cut off. Figure 6A rim 49 is shown, which has been cut and trimmed, thus having a clean edge. The end piece can also be cut off with a rotary cutter, creating an rim 49 with a stepped step 51. A sealing element 53, for example, an aluminum foil, can be sealed onto the step 51. This hermetically seals the open second end 21, and the product can be stored in the cartridge for a very long time in its original sealed state.

[0050] In the Figures 9 to 12 An embodiment of the cartridge 11 is shown in which the first end 19 is reinforced. This reinforcement is important for the coextruded cartridge 11, since the coextruded layers result in lower stability than injection-molded cartridges with increased material usage to achieve the necessary barrier properties.

[0051] In the Figures 9 and 11A cartridge precursor 55 is shown, which is blown from the coextruded tube in a blow mold 57. The blow mold 57 has a slide 59 at the lower end, at which the first end 19 is formed, and at which the extension 15 is also formed. The slide 59 can be formed from a first Figure 9 shown position into a second one in the Figure 10 shown position. In the first position, the cartridge precursor 55 or the first end 19 is formed. Adjacent to the slide, an annular recess 61 is provided on the casing 13 of the blow mold. A bulge 63 is formed on the cartridge precursor 55 through the recess 61.

[0052] When the slide 59 is moved into the second position, the shoulder 20 is displaced or bent into the interior of the cartridge precursor 55, creating the cartridge 11. This gives the first end 19 an undercut 65, which improves the mechanical stability of the first end 19 and the entire cartridge 11. The bulge 63 moves radially inward as the shoulder 20 is displaced, giving the shoulder 20 more material to form the undercut 65. The undercut has a height of between 2 and 10 mm, and preferably between 2 and 5 mm. The edge region of the shoulder 20 displaced into the interior of the cartridge 11 rests against the inside of the casing 13 and is preferably welded or glued thereto.

[0053] It is also possible for the slider 59 to be displaced even further into the interior of the cartridge 11. This also draws a portion of the jacket 13, which adjoins the shoulder 20, to form the undercut 65. This portion of the jacket 13 is also bent inward. Accordingly, this portion of the jacket 13 also rests against the inner surface of the jacket and can be welded or glued to it. Displacing the slider 59 further increases the mechanical stability of the first end 19. In this case, the undercut 65 has a height of between 10 and 20 mm.

[0054] The process for producing the cartridge 11 also includes a recycling process in which used and completely empty cartridges 11 are used to produce the second layer 27. Other recycling streams can also be used to produce the second layer, but it is preferable to primarily use used cartridges 11 to maintain a closed product cycle.

[0055] The used cartridges 11 are cleaned, i.e., freed of product residues, and melted and extruded as flakes or granules in an extruder. In further extruders, the required plastic starting material for layers 25, 29, 31, 33, and 35 is prepared using the coextrusion blow molding process. The plastics are combined in a storage head and coextruded into a multilayer tube. The multilayer tube is inflated in a blow mold, which is a split tool and has the negative shape of the cartridge. In the blow mold, the cartridge 11 receives the first closed end 19 and the second open end 21. The cartridge 11 is inflated over the second end 21, and the removal element in the form of the extension 15 or the nozzle 17 is formed at the first end 19.

[0056] As described above, an end portion of the jacket is cut off to obtain a specific length of the cartridge 11 and a defined edge 49. The cut-off end portion can be fed into the recycling stream and thus serve to produce the second layer 27 of a new cartridge 11. Legend:

[0057] 11Cartridge 13Jacket 15Extension, dispensing element 17Nozzle; dispensing element 19First end 20Shoulder 21Second end 22Filling opening 23Piston 25First layer 27Second layer 29Third layer 31Barrier layer 33First adhesive layer 35Second adhesive layer 37External thread 39Cap 41Retaining band 43Cutting lines 45Connecting piece 47Transparent strip 49Rim 51Step 53Sealing element 55Cartridge precursor 57Blow mold 59Slider 61Annular recess 63Bump 65Undercut, edge area

Claims

1. Cartridge (11) produced from a plastic material to be used in a commercially available cartridge press comprising: - a cylindrical sheath (13) with a first closed end (19) comprising a shoulder (20) and a second open end (21), wherein the open end (21) forms a filling opening (22) and a piston (23) that is displaceable with the cartridge press in direction of the first end can be inserted into the open end (21) and - a withdrawal element (15, 17) closed and molded at the first end (19) for withdrawing the product filled in the cartridge (11), which withdrawal element (15, 17) is integrally formed with the sheath (13), wherein the cartridge (11) is coextrusion blow molded and comprises at least a first outer and a second coextruded layer (25, 27), characterized in - that the second layer (27) is made of a recycled plastic material and - that the cartridge (11) comprises a third layer (29) that is produced from a new plastic material and that the second layer (27) is arranged between the first and the third layer (25, 29).

2. Cartridge according to claim 1, characterized in that the first layer (25) is produced from a new plastic material, preferably of white color.

3. Cartridge according to one of the preceding claims, characterized in that the cartridge (11) comprises a barrier layer (31) that is arranged between a first and a second adhesive layer (33, 35) and the barrier layer (31) is arranged with the adhesive layers (33, 35) inside the first layer (25).

4. Cartridge according to claim 3, characterized in that the barrier layer (31) is arranged with the adhesive layers (33, 35) between the first and the second layer (25, 27).

5. Cartridge according to claim 3 or 4, characterized in that the barrier layer (31) is made of ethylene-vinyl alcohol copolymer (EVOH) or polyamide.

6. Cartridge according to one of the preceding claims, characterized in that the first layer (25) and the third layer (29) represent a maximum of respectively 20 weight percent of the cartridge weight and the third layer up to 80 weight percent of the cartridge weight.

7. Cartridge according to one of the preceding claims, characterized in that the wall thickness of the sheath (13) that result from the sum of the layer thicknesses is preferably between 0,7 mm and 2,1 mm and preferably between 0,9 mm and 1,5 mm.

8. Cartridge according to one of the preceding claims, characterized in that a partial area of the shoulder (20) of a cartridge primary product (55) made of a hose is irreversibly displaced into the cartridge inside in such a manner that the first end (19) is configured undercut at the cartridge (11) at least in a partial area, wherein the edge area (65) of the undercut first end is formed from a partial area of the shoulder (20) or from a partial area of the shoulder (20) and of the adjoining sheath (13) of the cartridge primary product (55) by bending and / or compression.

9. Cartridge according to one of the preceding claims, characterized in that the open end (21) comprises an edge (49) that is formed by cutting an end piece of the cartridge (11) and preferably comprises a circumferential step (51).

10. Cartridge according to one of the preceding claims, characterized in that the plastic material of the first and of the second layer is a HDPE or an extrudable PET.

11. Set made of a cartridge (11) according to one of the preceding claims, a piston (23) that can be inserted into the second end (21) after filling of the cartridge (11) and a nozzle with an inner thread, which nozzle can be screwed onto the outer thread of the withdrawal element.

12. Method for producing a cartridge (11) according to one of the preceding claims according to the coextrusion blow molding procedure, wherein - different plastic materials are melted in several extruders, - the plastic materials are brought together in an accumulator head, - are coextruded to a multilayered hose, - the hose is blown in a blow mold that is a divided tool and has the negative form of the cartridge (11), characterized in that a new plastic material and a recycled plastic material are melted and coextruded to a first and a second layer (25, 27) and that a further new plastic material is coextruded in a third layer (29), wherein the second layer (27) is extruded between the first and the third layer (25, 29).

13. Method according to claim 12, characterized in that the recycled plastic material originates from a recycling flow of reused cartridges (11) without any residuals produced according to the coextrusion blow molding procedure.

14. Method according to claim 12 or 13, characterized in that the recycled plastic material is freed from product rests and is fed to the corresponding extruder for producing the second layer (27) as flakes or granules.

15. Method according to one of the claims 12 to 14, characterized in that a plastic material with barrier properties, preferably an ethylene-vinyl alcohol copolymer or a polyamide is coextruded as a barrier layer (31), wherein the barrier layer (31) is coextruded between a first and a second adhesive layer (33, 35).

16. Method according to one of the claims 12 to 15, characterized in that a cartridge primary product (55) is formed, wherein the hose in the blow mold receives a first closed end (19) comprising a shoulder and a second open end (21), the cartridge (11) is blown over the second end (21) and a withdrawal element (!5, 17) is molded at the first end (19).

17. Method according to claim 16, characterized in that a slider (59) of the blow mold (57) is displaced from a first position, in which the first end of the cartridge primary product (55) has been formed, to a second position in which at least a partial area of the first end (19) is irreversibly displaced into the cartridge inside that an undercut first end is formed at least in a partial area, wherein the edge area (65) of the undercut first end (19) is formed from a partial area of the shoulder or from a partial area of the shoulder (20) and of the adjoining sheath (13) of the cartridge primary product (55) by bending and / or compression.