DE102021209543A1 - Device and method for producing a ready-mixed rubber compound, in particular for vehicle tires - Google Patents

Abstract

The invention relates to a device (1) for producing a ready-made rubber mixture, in particular for the production of a vehicle tire, with a first and a second mixing device (2, 3), which each comprise a mixing chamber and a mixing unit for mixing a material located in the mixing chamber , a transfer device, by means of which the mixing chamber of the second mixing device (3) can be fed directly with material from the mixing chamber of the first mixing device (2), and a third mixing device (4) comprising a mixing chamber and a mixing unit, the third mixing device (4) can be charged with material from the mixing chamber of the second mixing device (3). The invention also relates to a method for producing a ready-made rubber mixture, in particular with a device (1) described, comprising at least the following steps:- Mixing a rubber mixture with at least one component selected from the group consisting of carbon black, silica, auxiliaries, silanes, oil and mastication aids in a first mixing device (2) to form a first mixture, - transferring the first mixture to a second mixing device (3), - feeding at least one material to the first mixture into the second mixing device (3), the material being selected from the Group consisting of a finished rubber material, carbon black and auxiliary chemicals, - mixing the second mixture in the second mixing device (3), - transferring the second mixture into a third mixing device (4), and - mixing the third mixture in the third mixing device (4). a ready-mixed rubber.

Description

The invention relates to a device for producing a ready-made rubber mixture, in particular for vehicle tires, according to the preamble of claim 1. The invention also relates to a method for producing a ready-made rubber mixture, in particular for vehicle tires, according to the preamble of claim 9 and the use of the device described.

Devices and methods for producing rubber mixtures are known in the prior art. A rubber compound is generally produced in two mixing stages, namely by producing a rubber base compound and a rubber ready compound. The production of the rubber base compound includes a mixing process in which the components such as rubber, fillers, processing agents, anti-aging agents, anti-ozonants and other common additives with the exception of vulcanization chemicals (sulphur, vulcanization accelerators, resins, etc.) are mixed together with the input of energy. The finished rubber base mixture is then cooled and possibly stored. The preparation of the ready mix includes a mixing process in which the remaining additives, such as the vulcanization components, are mixed in at the lowest possible temperatures.

In the present case, the invention relates to the production of a ready-made rubber compound, this being produced in one process without the rubber base compound or an intermediate product being substantially cooled. Rubber ready mixes can be produced, inter alia, in tandem mixers which comprise an upper machine and a lower machine arranged below the upper machine. Such tandem mixers are, for example, from EP 0 618 055 A1 and the WO 2017/097452 A1 known. In the prior art, the ready-made rubber mixture is usually produced in two process steps: production of the basic rubber mixture in at least one mixing operation and production of the ready-made rubber mixture in a second mixing operation. Furthermore, the rubber base compound and the rubber compound compound can be produced in the tandem mixer in one step, with the rubber base compound being produced in the upper mixer and the rubber compound compound being produced in the lower mixer. The disadvantage of the latter method is that the overall yield depends heavily on the necessary mixing and/or reaction time of the rubber base mixture.

This is where the present invention comes in. It is the object of the present invention to provide an apparatus for preparing a rubber compound, in particular for vehicle tires, by which the efficiency is improved. Furthermore, the object of the invention is to provide a method for producing a ready-made rubber mixture, in particular for vehicle tires, by means of which the ready-made rubber mixture can be produced more efficiently.

The object is achieved by a device for producing a ready-mixed rubber compound having the features of claim 1. Furthermore, the object is achieved by a method having the features of claim 9 and the use of the device having the features of claim 12.

• - einer ersten und einer zweiten Mischeinrichtung, insbesondere einer zweiten diskontinuierlichen Mischeinrichtung, welche jeweils eine Mischkammer und ein Mischaggregat zum Mischen eines sich in der Mischkammer befindenden Materials umfassen, und
• - eine Übergabeeinrichtung, mittels welcher die Mischkammer der zweiten Mischeinrichtung direkt mit Material aus der Mischkammer der ersten Mischeinrichtung beschickbar ist,

und einer dritten Mischeinrichtung umfassend eine Mischkammer und ein Mischaggregat, wobei die dritte Mischeinrichtung mit Material aus der Mischkammer der zweiten Mischeinrichtung beschikbar ist.The object is achieved by a device for producing a ready-mixed rubber compound, in particular for the production of a vehicle tire

• - a first and a second mixing device, in particular a second discontinuous mixing device, which each comprise a mixing chamber and a mixing unit for mixing a material located in the mixing chamber, and
• - a transfer device, by means of which the mixing chamber of the second mixing device can be charged directly with material from the mixing chamber of the first mixing device,

and a third mixing device comprising a mixing chamber and a mixing unit, wherein the third mixing device can be charged with material from the mixing chamber of the second mixing device.

Advantageously, the yield is significantly improved by the device according to the invention. With the device according to the invention, the ready-made rubber mixture is produced in one mixing pass, with the mixture usually not being cooled during the mixing pass.

According to the invention, a mixing cycle has at least three steps, the first mixing step taking place in the first mixing device, the second mixing step taking place in the second mixing device and the third mixing step taking place in the third mixing device. The three mixing devices can be arranged one behind the other or one above the other. It is essential that a mixing process takes place in at least all three mixing devices, which leads to a ready-mixed rubber mixture. According to the invention, a ready-mixed rubber has at least vulcanization components. In a preferred embodiment, the third mixing device is arranged downstream in a tandem mixer or a tandem mixer, in that the first mixing device is above the second mixing device and the second mixing device is above the third mixing device device are arranged. Advantageously, the mixing devices are fed into a mixer arranged one above the other with the aid of gravity.

In a further preferred embodiment, the device is particularly suitable for the production of ready-made rubber mixtures comprising silica and/or at least one multi-stage rubber mixture. Such a device comprising a third mixing device advantageously leads to an improved yield, since the mixing times in the three mixing devices are similarly long. This has been shown to be particularly the case with ready-mixed rubbers that contain silica or that contain multiple rubber compounding steps. A multi-stage rubber mixture is, for example, a rubber mixture that comprises a material mixture from the first and/or the second and/or third mixing device and/or an after-treated rubber mixture.

Advantageously, the cycle time (production batch/time unit) can be shortened by mixing in a multi-stage rubber mixture, so that the yield is significantly improved.

Furthermore, the transfer device within the meaning of the invention is designed in such a way that it can transfer material from the previous mixing device to the subsequent mixing device. For example, such a transfer device can include a flap that lets material through when open. The transfer devices are advantageously designed in such a way that the material does not cool down significantly.

The third mixing device preferably comprises a continuous mixer or a conical twin-screw mixing extruder or a two-roll plasticizer or a planetary roller extruder. It has been found to be advantageous that the continuous mixer from Farrel is particularly suitable. Furthermore, it has turned out to be advantageous that the two-roller plasticizer from UTH is particularly suitable. The use of one of the mixing units described advantageously leads to a significantly better efficiency and an improved yield in the production of rubber ready-mixes, in particular comprising silica or a multi-stage rubber mixture.

Furthermore, the third mixing device is preferably a continuous mixing device. Advantageously, it was able to be shown that the yield of the finished rubber mixture is improved if the mixing process in the third mixing device takes place continuously. It is essential for this that the third mixing device comes continuously with material from the second mixing device (from a discontinuous to a continuous mixing process).

In a further preferred embodiment, the device comprises a second transfer device, by means of which the third mixing device can be fed with material from the mixing chamber of the second mixing device or from a twin-screw extruder upstream of the third mixing device. The second transfer device basically connects the second mixing device to the third mixing device or, alternatively, the second mixing device to an upstream twin-screw extruder, with the twin-screw extruder only being designed to convey the material into a subsequent third mixing device. Such an upstream twin-screw extruder differs from the third mixing device in that it does not mix, but only transports the material. The second transfer device can be a flap, for example, through which material can be conveyed.

More preferably, the device comprises at least one feed device with which material can be fed into the first and/or second and/or third mixing device and/or into the first and/or second transfer device. The feed device can be a conveyor belt or a loading chute, for example. The supply of additional materials is possible through the at least one supply device. At least one rubber and at least one component selected from the group consisting of carbon black, silica, auxiliaries, silanes, oil and what the mastication auxiliaries are preferably fed into the first mixing device. A material selected from the group consisting of a post-processed rubber material, carbon black and auxiliary chemicals is preferably fed into the second mixing device. Vulcanizing agent and/or post-processed rubber mixtures are preferably fed into the third mixing device. Alternatively or additionally, the aforementioned materials can also be fed into at least one of the transfer devices. It has advantageously been shown that a controlled supply of the material into the first and/or second mixing device in conjunction with the third mixing device, in particular with a continuous third mixing device, leads to a significantly improved yield.

The materials mentioned are particularly preferably fed into the third mixing device during the mixing process in the third mixing device. It's a significant benefit when the It is supplied during the mixing process, as this increases the efficiency and quality (distribution of the mixture) of the entire process.

Furthermore, the device preferably comprises at least one control unit for controlling the dwell time of the material and/or the temperature of the material in at least one of the mixing devices and/or at least one of the transfer devices and/or at least one of the feed devices. The control unit is set up to control the process in such a way that a continuous mixing process can be made possible in the third mixing device. It is also important that the material does not cool down in between, so that the entire mixing process can run continuously. In particular, the temperature in the third mixing device should not reach the vulcanization temperature. The temperature in the third mixing device is particularly preferably in the range from 100-130.degree.

Furthermore, the device preferably comprises a weighing unit for determining the material weight and/or a volumetric dosing unit in at least one of the mixing devices and/or in at least one transfer device and/or in at least one of the feed devices. The materials are weighed or volumetrically dosed outside of the mixing chamber. It is emptied into the mixing chamber or in the transfer device. Advantageously, the material is weighed before and during feeding into one of the mixing devices. It is conceivable that the weighing unit or the volumetric and/or gravimetric dosing unit is connected to the control unit so that a time-controlled mixing process can take place. However, it is also conceivable for the materials to be prepared manually (gravimetrically and/or volumetrically) in a separate step.

Furthermore, the third mixing device preferably comprises a shaping unit at the outlet for finalizing the geometry of the finished rubber mixture. Such a molding unit can be a gear pump, for example.

In a further preferred embodiment, the third mixing device has an infeed unit in the area of the inlet opening, particularly preferably at least one stuffer and/or at least one pair of gear wheels and/or at least one intermediate twin-screw extruder (TSRD), through which the material can also be introduced into the third mixing device . In addition, such an import unit can advantageously ensure a continuous mixing process. For this purpose, the infeed unit can be connected to the control unit in order to control the infeed of the material into the third mixing unit. It is also conceivable that the import unit can also communicate with the weighing unit.

• - eine erste und eine zweite Mischeinrichtung, welche jeweils eine Mischkammer und ein Mischaggregat zum Mischen eines sich in der Mischkammer befindenden Materials umfasst,
• - eine erste Übergabeeinrichtung, mittels welcher die Mischkammer der zweiten Mischeinrichtung direkt mit Material aus der Mischkammer der ersten Mischeinrichtung beschickbar ist,
• - eine zweite Übergabeeinrichtung und einen Doppelschneckenextruder, durch den der Doppelschneckenextruder mit Material aus der Mischkammer der zweiten Mischeinrichtung beschickbar ist,
• - und eine dritte Mischeinrichtung umfassend eine Mischkammer und ein Mischaggregat, wobei die dritte Mischeinrichtung mit Material aus dem Doppelschneckenextruder beschikbar ist.

In a further preferred embodiment, the device for producing a ready-made rubber mixture, in particular for the production of a vehicle tire,

• - a first and a second mixing device, each of which comprises a mixing chamber and a mixing unit for mixing a material located in the mixing chamber,
• - a first transfer device, by means of which the mixing chamber of the second mixing device can be fed directly with material from the mixing chamber of the first mixing device,
• - a second transfer device and a twin-screw extruder, through which the twin-screw extruder can be fed with material from the mixing chamber of the second mixing device,
• - and a third mixing device comprising a mixing chamber and a mixing unit, wherein the third mixing device can be loaded with material from the twin-screw extruder.

It is conceivable that in such an embodiment the material is conveyed from the twin-screw extruder into the third mixing device via a conveyor belt. Such a device particularly preferably has a third transfer device, through which the third mixing device can be charged, in particular in a continuous mixing process.

• - Mischen einer Kautschukmischung mit mindestens einer Komponente ausgewählt aus der Gruppe bestehend aus Ruß, Silika, Hilfsmittel, Silane, Öl und Mastikationshilfsmittel in einer ersten Mischeinrichtung zu einer ersten Mischung,
• - Überführen der ersten Mischung in eine zweite Mischeinrichtung,
• - Zuführen von mindestens einem Material zur ersten Mischung in die zweite Mischeinrichtung, wobei das Material ausgewählt ist aus der Gruppe bestehend aus einem nachbearbeitetem Kautschukmaterial, Ruß und Hilfschemikalien,
• - Mischen der Mischung in der zweiten Mischeinrichtung zu einer zweiten Mischung,
• - Überführen der zweiten Mischung in eine dritte Mischeinrichtung und
• - Mischen der Mischung in der dritten Mischeinrichtung zu einer Kautschukfertigmischung, wobei insbesondere kontinuierlich nachgearbeitetes Kautschukmaterial, Vulkanisationsmittel und/oder Hilfsmittel zugesetzt werden.

Furthermore, the object of the invention is achieved by a method for producing a ready-made rubber mixture, in particular with a device described, comprising at least the following steps:

• - Mixing a rubber mixture with at least one component selected from the group consisting of carbon black, silica, auxiliaries, silanes, oil and mastication auxiliaries in a first mixing device to form a first mixture,
• - transferring the first mixture into a second mixing device,
• - feeding at least one material for the first mixture into the second mixing device, wherein the material is selected from the group consisting of a post-processed rubber material, carbon black and auxiliary chemicals,
• - mixing the mixture in the second mixing device to form a second mixture,
• - transferring the second mixture into a third mixing device and
• - Mixing the mixture in the third mixing device to form a ready-made rubber mixture, in particular continuously reworked rubber material, vulcanizing agents and/or auxiliaries being added.

Advantageously, a significantly better yield can be achieved by the method according to the invention, in particular for ready-made rubber mixtures comprising silica and/or at least one multi-stage rubber mixture. The multi-stage rubber compound can comprise, for example, the said first compound and/or second compound and/or ready-made rubber compound and/or a post-processed rubber compound. A key benefit of adding post-processed rubber compounds is improved dispersion and/or compound viscosity, which improves processability and ultimately yield.

Auxiliaries can be, for example, plasticizers and/or additives and/or adhesion promoters and/or other customary auxiliaries. Mastication aids can also be, for example, oxidizing agents and/or disulfides and/or thiophenols and/or others. Auxiliary chemicals also include, for example, aging inhibitors and/or vulcanization accelerators and/or retarders.

In a preferred embodiment, the first two process steps are carried out batchwise and the third process step is carried out continuously. The supply of material to the first mixing device and the second mixing device is controlled in such a way that the third mixing device can be fed continuously with material. This is advantageous in particular in the case of ready-made rubber mixtures comprising silica and/or at least one multi-stage rubber mixture, since the mixing times in the mixing devices are similarly long.

Preference is given to material that is fed directly to the third mixture in the third mixing device via at least one feed device, in particular vulcanizing agents and/or post-processed rubber mixtures. It is essential that the material is added during the mixing process. A key benefit is that feed can/should be in metered amounts or volumes, thereby improving yield. Gravimetric screw feeders or vibratory feeders, volumetric extruder gear feeders, etc. can be used as feed devices.

Furthermore, the second mixture is preferably introduced into the third mixing device via an introduction device, preferably via at least one stuffer and/or at least one pair of gear wheels and/or an interposed twin-screw extruder. The introduction of material via the introduction device is particularly preferably controlled in such a way that the third mixing device can mix continuously.

Further preferably, the mixing of the third mixture to form the ready-made rubber mixture takes place in a continuous mixer or a conical twin-screw mixing extruder or a two-roll plasticizer or a planetary roller extruder.

In addition, the invention relates to the use of a device as described for the production of a rubber compound, wherein the rubber compound comprises silica or a treated rubber compound.

Further advantages and features of the device according to the invention and of the method result from the dependent claims, which relate to advantageous configurations of the present invention and as such are not to be understood as limiting. The invention also includes combinations of the features of different subclaims, insofar as these are technically possible, even if the subclaims do not relate to one another or if they belong to different claim categories. Furthermore, combinations of preferred and particularly preferred embodiments can also be combined with one another, insofar as these are technically possible. This also applies to the individual features of the exemplary embodiments discussed below, insofar as these are not recognizable to the person skilled in the art as necessarily belonging to one another.

character list

• 1 eine Ausführungsform der erfindungsgemäßen Vorrichtung und
• 2 eine weitere Ausführungsform der erfindungsgemäßen Vorrichtung.

Further details and advantages of the present invention result from the following description of the exemplary embodiments in conjunction with the drawings. in this show

• 1 an embodiment of the device according to the invention and
• 2 another embodiment of the device according to the invention.

1 shows schematically an embodiment of the device 1 according to the invention with a first mixing device 2, a second mixing device 3 and a third mixing device 4, wherein the three mixing devices 2, 3, 4 are arranged one above the other. The device 1 also comprises a first transfer chute 5 and a second transfer chute 6 and a ram 7 through which material can be fed into the first mixing device 2 and a conveyor belt 8 through which material can be fed into the second mixing device 3 . The third mixing device 4 comprises a third feed device 9, through which material can be fed into the third mixing device 4 in the mixing process. At least one rubber mixture with at least one component selected from the group consisting of carbon black, silica, auxiliaries, silanes, oil and mastication auxiliaries is fed into the first mixing device 2 via the ram 7 . The material selected from the group consisting of a post-processed rubber material, carbon black and auxiliary chemicals is fed to the second mixing device 3 via the conveyor belt 8 . Vulcanizing agents and/or post-processed rubber mixtures are fed into the third mixing device 4 via a third or more feed device/s 9 . In addition, the device 1 comprises two stuffers 10 which introduce the material into the third mixing device 4 . The stuffers 10 are designed in such a way that they push the material into the third mixing device 4 by means of a stuffing movement. The mixing device 4 also has two rollers, by which the material at the end of the mixing device 4 is formed.

2 shows schematically another embodiment of the device 1 according to the invention with a first mixing device 2, a second mixing device 3, a twin-screw extruder 11 and a third mixing device 4. The material to be mixed is pressed into the first mixing device 2 via a stamp 7. The material mixture is then fed into the second mixing device 3 via the first transfer chute 5 . Other materials can be added via the conveyor belt 8 . Following the second mixing device 3 , the material mixture is fed through the second transfer shaft 6 into the twin-screw extruder 11 . This transports the material mixture and guides it onto a second conveyor belt 12. The material mixture is fed from the second conveyor belt 12 into the third mixing device 4 via a third transfer chute 13. Two pushers 10 also convey the material into the third mixing device 4. During the mixing process in further additives are fed in to the third mixing device 4 via the third feed device 9 . These include, for example, vulcanization chemicals and/or auxiliary chemicals. At the end of the third mixing device 4, a ready-made rubber mixture is obtained.

• Beispiel 1: Die Gesamtmisch- und Reaktionszeit einer auf Silika basierten Grundmischung beträgt ca. 360 Sekunden, die aufgeteilt ist auf zwei Mischer mit ca. 200 Sekunden. Die Mischzeit einer Kautschukfertigmischung beträgt ca. 150 Sekunden (kontinuierlich), wobei der Ausstoß für ein Batch somit alle 200 Sekunden erfolgt.
• Beispiel 2: In einem ersten Schritt zur Herstellung der Kautschukgrundmischung erfolgt die Einarbeitung von Kautschuk, Russ und anderen Zusätzen. Im ersten Mischer beträgt die Mischzeit ca. 150 Sekunden, einem zweiten Schritt zur Herstellung eines Remills im zweiten Mischer ca. 120 Sekunden und die Herstellung einer Kautschukfertigmischung in einem dritten Mischer ca. 150 Sekunden. Der Ausstoß eines Batch erfolgt somit alle 230 Sekunden.

Examples of a total mixing and reaction time for a silica-based masterbatch:

• Example 1: The total mixing and reaction time of a silica-based masterbatch is approx. 360 seconds, which is divided between two mixers with approx. 200 seconds. The mixing time for a ready-mixed rubber is approx. 150 seconds (continuous), with a batch being discharged every 200 seconds.
• Example 2 In a first step in the production of the rubber base compound, rubber, carbon black and other additives are incorporated. The mixing time in the first mixer is approx. 150 seconds, a second step for producing a remill in the second mixer is approx. 120 seconds and the production of a ready-mixed rubber in a third mixer is approx. 150 seconds. A batch is therefore ejected every 230 seconds.

Reference List

1

contraption

2

first mixing device

3

second mixing device

4

third mixer

5

first transfer shaft

6

second transfer shaft

7

Rubber stamp

8th

first conveyor belt

9

third feeder

10

two stoppers

11

twin screw extruder

12

second conveyor belt

13

third transfer shaft

QUOTES INCLUDED IN DESCRIPTION

This list of 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

• EP 0618055 A1 [0003]
• WO 2017097452 A1 [0003]

Claims (12)

Device (1) for producing a rubber ready-mix, in particular for the production of a vehicle tire, with - a first and a second mixing device (2, 3), which each comprise a mixing chamber and a mixing unit for mixing a material located in the mixing chamber, and - a transfer device, by means of which the mixing chamber of the second mixing device (3) can be fed directly with material from the mixing chamber of the first mixing device (2), characterized by a third mixing device (4) comprising a mixing chamber and a mixing unit, the third mixing device (4) can be charged with material from the mixing chamber of the second mixing device (3). Device (1) after claim 1 , characterized in that the third mixing device (4) comprises a continuous mixer or a conical twin-screw mixing extruder or a two-roll plasticizer or a planetary roller extruder. Device (1) after claim 1 or 2 , characterized in that the third mixing device (4) is a continuous mixing device. Device (1) according to one of the preceding claims, characterized in that the device (1) comprises a second transfer device (6), by means of which the third mixing device (4) with material from the mixing chamber of the second mixing device (3) or from a before the third mixing device (4) upstream of the twin-screw extruder (11) can be charged. Device (1) according to one of the preceding claims, characterized in that the device (1) comprises at least one feed device (9) with which material is fed into the first and/or second and/or third mixing device (2, 3, 4) and / or can be fed into the first and/or second transfer device (6). Device (1) according to one of the preceding claims, characterized in that the device (1) has at least one control unit for controlling the residence time of the material and/or the temperature of the material in at least one of the mixing devices (2, 3, 4) and/or at least one of the transfer devices (5, 6, 13) and/or at least one of the feed devices (9). Device (1) according to one of the preceding claims, characterized in that the device has a weighing unit for determining the weight of the material and/or a volumetric dosing unit in at least one of the mixing devices (2, 3, 4) and/or in at least one transfer device (5, 6, 13) and/or in at least one of the feed devices (9). Device (1) according to one of the preceding claims, characterized in that the third mixing device (4) in the area of the inlet opening has an infeed unit, in particular at least one stuffer (10) and/or at least one pair of gear wheels and/or at least one interposed TSRD which the material can also be introduced into the third mixing device (4). Method for producing a rubber ready-mix, in particular with a device (1) according to one of the preceding claims, comprising at least the following steps: - Mixing a rubber mixture with at least one component selected from the group consisting of carbon black, silica, auxiliaries, silanes, oil and mastication auxiliaries in a first mixing device (2) to form a first mixture, - transferring the first mixture into a second mixing device (3), - feeding at least one material for the first mixture into the second mixing device (3), the material being selected from the group consisting of a post-processed rubber material, carbon black and auxiliary chemicals, - mixing the second mixture in the second mixing device (3), - transferring the second mixture into a third mixing device (4) and - Mixing the third mixture in the third mixing device (4) to form a ready-made rubber mixture. procedure after claim 9 , characterized in that material is fed directly to the third mixture in the third mixing device (4) via at least one feed device (9), in particular vulcanizing agent and/or post-processed rubber mixtures. Method according to one of the preceding claims, characterized in that the mixing of the third mixture to form the ready-mixed rubber takes place in a continuous mixer or a conical twin-screw mixing extruder (11) or a two-roll plasticizer or a planetary roller extruder. Use of a device according to any one of Claims 1 until 8th for the production of a rubber ready mix, wherein the rubber ready mix composition comprises silica or a treated rubber compound.

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