DE102011112081A1 - Process for processing elastics - Google Patents

Abstract

According to the invention, planetary roller extruders with transport spindles are used both for the crosslinking of elastomers and for their devulcanization.

Description

The invention relates to a process for the processing of natural and artificially produced elastomers and comparable substances.

The elastomers and comparable substances have a significant importance in the economy / technology. Wherever plastic is supposed to undergo a particularly pronounced deformation and should nevertheless return to its original shape after being relieved of strain, rubber-elastic plastics (rubber) are being considered via elastomers (elastics) and the like. Plastics consist of large molecule chains. The high elasticity of the elastomers is given by a phenomenon in the behavior of the molecular chains. In a tensile load of the original molecular chains lying in the ball, the molecular chains arrange differently, preferably in parallel, and stretch the molecular chains.

However, the prerequisite for the desired deformation is that the molecular chains do not slide against each other. This is achieved by networking the molecular chains. The degree of crosslinking influences the deformation. Low crosslinking creates a soft plastic. Strong networking creates a hard plastic.

There are different cross-linking agents. Depending on the plastic, a selection of crosslinking agents takes place. Sulfur is one of the commonly used crosslinking agents. Sulfur occurs with appropriate heating of the plastic as a crosslinking agent in action. Other crosslinking agents do not depend on heat effect or the effect of the crosslinking agent may also depend on other circumstances.

The elastomers include, for example
Acrylonitrile / butadiene / acrylate (A / B / A)
Acrylonitrile / chlorinated polyethylene / styrene (A / PE-C / S)
Acrylonitrile / methyl methacrylate (A / MMA)
Butadiene rubber (BR)
Butyl rubber (HR)
Chloroprene rubber (CR)
Ethylene-ethyl acrylate copolymer (E / EA)
Ethylene-propylene copolymer (EPM)
Ethylene-propylene-diene rubber (EPDM)
Ethylene vinyl acetate (EVA)
Fluororubber (FPM or FKM)
Isoprene rubber (IR)
Natural rubber (NR)
Polyisobutylene (PIB)
Polyvinyl butyral (PVB)
Silicone rubber (Q or SIR)
Styrene butadiene rubber (SBR)
Styyroole-buradien-styrene (SBS)
Thermoplastic polyurethane (TPU or TPE-U)
Vinyl chloride / ethylene (VC / E)
Vinyl chloride / ethylene / methacrylate (VC / E / MA)

For a continuous processing of the plastic has long been known to use planetary roller extruder. Such processes and corresponding planetary roller extruders are described in particular in the following publications: DE 19939075A1 . CA 698518 . DE19653790A . DE 19638094A1 . DE 19548136A1 . DE1954214A . DE3908415A . DE19939077A . EP1078968A1 . EP1067352A . EP854178A1 . JP3017176 . JP11080690 . JP9326731 . JP11-216754 . JP1 1-216764 . JP10-235713 . WO2007 / 0874465A2 . WO2004 / 101627A1 . WO2004 / 101626A1 . WO 2004/037941 A2 . EP1056584 . PCT / EP99 // 00968 . WO 94/11175 . US6780271B1 . US7476416 ,

Planetary gear extender sections / planetary roller extruder modules are used when an extruder is composed of several sections / modules and the sections / modules in question show a planetary roller extruder design. There are both sections / modules with the same construction as well as sections of different construction before. That is, planetary roller extruder modules / planetary roller extruder sections may also be used with sections of other types, for example, single-screw extruder sections / modules.

A planetary roller extruder has a central spindle, an internally toothed housing and between housing internal teeth and the central spindle different planetary spindles. The planetary spindles mesh with both the central spindle and the internally toothed extruder housing. The planetary spindles run around the central spindle. For details and variations of known planetary roller extruders or sections / modules, reference is made to the following references:
DE 10 2005 007 952 A1 . DE 10 2004 061 068 A1 . DE 10 2004 038 875 A1 . DE 10 2004 048 794 A1 . DE 10 2004 048 773 A1 . DE 10 2004 048 440 A1 . DE 10 2004 046 228 A1 . DE 10 2004 044 086 A1 . DE 10 2004 044 085 A1 . DE 10 2004 038 774 A1 . DE 10 2004 034 039 A1 . DE 10 2004 032 694 A1 . DE 10 2004 026 799 B4 . DE 10 2004 023 085 A1 . DE 10 2004 004 230 A1 . DE 10 2004 002 159 A1 . DE19962886A1 . DE19962883A1 . DE19962859A1 . DE19960494A1 . DE19958398A1 . DE19956803A1 . DE19956802A1 . DE19953796A1 . DE19953793A1 ,

• a) das Spiel zwischen den bewegten Planetwalzenteilen
• b) die Anzahl der Planetspindeln
• c) die Verzahnung der Planetwalzenteile

For the adjustment you can change the planetary roller extruder:

• a) the game between the moving planetary gear parts
• b) the number of planetary spindles
• c) the teeth of the planetary roller parts

To a)

With the clearance between the moving planetary roller parts, the amount of deformation that the elastomers undergo as it passes between the teeth of the planetary roller parts is determined. The smaller the game, the stronger the deformation. The bigger the game, the lower the deformation.

To b)

The special feature of planetary roller extruders or on planetary roller extruder sections in relation to extruders and extruder sections of a different design is, in addition to extreme deformation performance, a cavity between the planetary spindles revolving around the central spindle. The elastomers can flow into the cavity.

The cavity is affected by changing the number of planetary spindles. The smaller the number of planetary spindles, the larger the cavity becomes.

To c)

The teeth can have different texture.

Optionally, a normal toothing or a hedgehog toothing or a knob toothing of the revolving planetary spindles is provided.

The known hedgehog toothing is preferably formed from a standard toothing, by annular grooves are incorporated in the planetary spindles at axial intervals.

The studded toothing preferably arises from the normal toothing.

The normal toothing of planetary spindles is characterized on the one hand by a cross section, as it show the interlocking teeth of the gears of a transmission. On the other hand, the teeth are not straight but spindle-shaped or like the threads of a screw thread along the circumference.

The threads are cut in this form in the starting material of the planetary spindles, z. B. turned or milled.

For the threads, a distinction is made between left-handed thread and right-handed thread. There are also multiple threads.

The same distinction is made on extruder spindles.

A knob toothing arises when z. B. in a right-handed gearing a left-handed groove is incorporated. By incorporating the groove then creates a left-toothing. In the case of original right-hand gearing, a left-handed groove is provided. In general, one can speak of opposing gearing.

Through the groove, the original threads of the planetary spindles are interrupted. The groove can have the same or a different slope (less or greater) than the original toothing of the corresponding planetary roller part. The slope of the groove preferably deviates at most by 50% from the pitch of the original toothing. Due to the interruptions (recesses) of the teeth of the original toothing remain after the incorporation of the above-described groove (opposing teeth) nubs of the original teeth. The knobbed toothing may be limited to individual planetary roller parts. The

Studded toothing can also be provided in several or in all planetary roller parts. Preferably, the planetary spindles are provided with a Noppenverzafnung.

The studded toothing can wholly or partially form the toothing on the planetary roller parts.

In the case of partial studded toothing on the planetary roller parts, it may be desirable to arrange the normally toothed part of the planetary roller parts in the conveying direction of the extruder at the rear end (at the discharge end of the planetary roller parts), in order to build up a delivery pressure therebetween, which will transfer the elastomers into the other (downstream) ) Ensures extruder area.

Optionally, napped toothed planetary spindles can also alternate with normally toothed planetary roller spindles and vice versa.

Optionally, individual normal-toothed planetary roller spindles between knobbed planetary roller spindles can be arranged or vice versa.

If the nub toothing is provided in a plurality of corresponding planetary roller parts, the nub toothing can be arranged so that the interruptions of the teeth in a planetary roller part are aligned with the interruptions in the corresponding planetary roller part or offset in relation to these interruptions. The offset may have a dimension equal to a fraction of the tooth gap between two teeth or a multiple of the tooth gap between two teeth, wherein a multiple may also be a number less than 2.

The interruption of the teeth creates openings into which the material to be extruded can flow.

The void volume described under b) and the nub toothing described under c) reduce the build-up of pressure from the planetary roller parts, so that the elastomers can remain in the extruder or in the extruder section for a necessary desired treatment time.

Preferably, the planetary roller extruder section has a length of at most 1200 mm with a diameter of up to 100 mm in the toothing of the planetary roller extruder housing, even more preferably of at most 1000 mm. For other diameters of the teeth of the planetary roller extruder housing result in correspondingly larger or smaller maximum lengths.

During extrusion, a considerable amount of energy is released in the extruder or in the extruder section, which is shown as heat in the elastomers. If the elastomers already reach the planetary roller extruder or the planetary roller extruder section at a considerable temperature and / or the energy introduced into the elastomers in the planetary roller extruder section results in excessive heating, the resulting heat is dissipated by cooling.

If the elastomers on entry into the planetary roller extruder or the extruder section does not have sufficient temperature, the above cooling is omitted. Optionally, even heat is supplied.

For cooling and / or heating conventional temperature control devices on planetary roller extruders are sufficient. It is customary to make the housing bivalve and to guide the tempering agent through the gap. It is also common to provide the central spindle with channels, is also passed through the Temperierungsmittel. The usual tempering agent is water or oil, with which is heated or cooled.

In processing the desired elastomers, compounded compounding ingredients and / or uncumbdimented compounding ingredients are generally combined in the extruder, homogenized and brought to the desired temperature and pressure so that crosslinking agent / vulcanizing agent becomes active in the elastomers which react to temperature and / or pressure ,

That has proven itself.

Nevertheless, the invention has set itself the task to improve the preparation of elastomers.

The invention has recognized that the quality of the crosslinking for the quality of the elastomers is essential.

The networking is optimized if the temperature conditions are met. In normal-toothed planetary spindles, observing the temperature conditions proves to be particularly difficult.

Hedgehog spindles make it easier to maintain temperature conditions. This also applies to Noppenspindeln. The hedgehog spindles as well as the knob spindles have been developed to increase the mixing performance.

The invention is to influence the temperature conditions the transport spindles (spindles with reduced tooth stock), which have arisen for other purpose.

During the development of the transport spindle, at least one tooth is removed on at least one normally toothed planetary spindle. Optionally, more teeth are removed. Preferably, at least three each remain evenly on the circumference of the planetary roller spindles. It can also be removed every fourth or every third or every second tooth. It can also be removed all teeth except for one tooth. This results in a reduced tooth stocking as opposed to non-reduced tooth stocking. The removal of the teeth is preferably carried out to the tooth base. It is also conceivable that a further material preparation, as well as a partial removal of the teeth.

The removal of the teeth creates a special planetary spindle shape.

Due to the entire or partial removal of certain teeth, a planetary roller spindle with more conveying effect than a pure stud spindle, with less mixing power than a pure stud spindle, is produced with the remaining teeth unchanged. The transport spindle can also be produced differently than by subsequent removal of teeth, for example by milling and grinding after the presentation of an existing transport spindle.

The invention has recognized that with the transport spindles less energy is carried in the material to be extruded, as with other planetary spindles. As a result, less cooling must be done or is the cooling while maintaining existing cooling devices more effective than with the use of other planetary spindles. This facilitates the maintenance of an advantageous temperature profile or allows more accurate compliance with crosslinking temperatures / vulcanization temperatures.

The subsequent removal of the teeth can have advantages:
As far as stockpiling of planetary roller spindles takes place and as far as compensation or hardening or other treatment to increase the wear resistance of the tooth surfaces is provided, the planetary roller spindles are preferably stored without the surface treatment, so that in retrospect, a simple inventive processing of the planetary roller spindles, z. B. by milling, is possible. The treatment of the tooth surfaces takes place after processing.

• a) bei einem Planetwalzengehäusedurchmesser (bezogen auf den Teilkreisdurchmesser der Innenverzahnung des Gehäuses) kleiner 160 mm eine erfindungsgemäß bearbeitete Mindest-Spindellänge von 200 mm, bevorzugt von mindestens 300 m und weiter bevorzugt eine Spindellänge von mindestens 400 mm und erfindungsgemäß bearbeitete Maximal-Spindellänge bis 1500 mm, vorzugsweise bis 1200 mm und höchst bevorzugt bis 900 mm für eine Planetspindel vorgesehen.
• b) bei einem Planetwalzengehäusedurchmesser (bezogen auf den Teilkreisdurchmesser der Innenverzahnung des Gehäuses) von 160 mm und mehr eine erfindungsgemäß bearbeitete Mindest-Spindellänge von mindestens 400 mm, bevorzugt von mindestens 800 m und weiter bevorzugt eine Spindellänge von mindestens 1200 mm und eine Maximal-Spindellänge bis 3000 mm, vorzugsweise bis 2500 mm und noch weiter bevorzugt bis 2000 mm vorgesehen.

Surprisingly, the removal of teeth does not affect the smoothness of the planetary roller spindles, because the teeth run like screws / threads on the surface of the planetary roller spindles. With sufficient length of the spindles and a corresponding pitch, the helical or thread-shaped teeth loop around the spindles so often that the planetary roller spindles between the central spindle and the surrounding housing are securely guided and fixed. In a planetary roller spindle where every other tooth has been removed, it is preferred according to the invention

• a) at a planetary roller housing diameter (based on the pitch circle diameter of the inner toothing of the housing) smaller than 160 mm according to the invention machined minimum spindle length of 200 mm, preferably of at least 300 m and more preferably a spindle length of at least 400 mm and inventively machined maximum spindle length to 1500 mm, preferably up to 1200 mm and most preferably provided to 900 mm for a planetary spindle.
• b) with a planetary roller housing diameter (based on the pitch circle diameter of the inner toothing of the housing) of 160 mm and more according to the invention machined minimum spindle length of at least 400 mm, preferably of at least 800 m and more preferably a spindle length of at least 1200 mm and a maximum spindle length to 3000 mm, preferably to 2500 mm and even more preferably to 2000 mm provided.

The above minimum spindle length refers to the toothing on the planetary spindle. To the minimum spindle spindle length preferably does not include the teeth, which arises in the above-described leakage of milling cutters and / or arises when entering the milling cutter to the specified milling depth when the planetary spindle length is greater than the toothed length of the planetary spindle.

The machining (removal of teeth) of the planetary roller spindles can be applied to all known tooth modules, in particular to the common modules 1.5 to 12 or beyond to 20. The tooth modules are to be distinguished from the above-mentioned planetary roller parts / modules. The tooth modules indicate the size of the teeth.

The planetary spindles (designed as transport spindles) described above are optionally used only in an extruder section of an extrusion line designed as a planetary roller extruder. These planetary spindles are preferably used for the processing of elastomers according to the invention in at least two extruder sections arranged one behind the other, even more preferably in at least three extruder sections arranged one behind the other.

The various extruder sections designed as planetary roller extruders are preferably arranged in one stage of the extrusion installation. Optionally, it may also be a multi-stage extrusion line. In two stages one speaks of a tandem system with a primary extruder and a secondary extruder. With more stages one speaks of a cascade plant. Then all extruder sections can concentrate on one of the stages with the planetary spindles designed as transport spindles. Optionally, the extruder sections with the planetary spindles designed as transport spindles can also be distributed over several stages of the extrusion plant.

The extrusion plant regularly includes an extruder section, which forms a filling zone for the materials to be processed. In most cases, this extruder section is designed as a single-screw extruder.

To the extrusion plant belongs usually also an end provided extruder section, in which the extruded material is brought to outlet temperature.

The planetary roller sections / extruder parts / modules are assembled with the other sections / modules to the respective desired extruder. It is customary to provide a common central spindle for all successively arranged modules one stage of an extrusion plant. The central spindle continues into associated extruder sections / modules designed as single-screw extruders as their screw. The modular design is comparable to a modular system and usually very economical.

The various planetary parts (central spindle / planetary spindles / internal teeth) of a section / module regularly have the same tooth module.

For the alternative production of the transport spindles, the procedure may be as follows:
This can be linked to conventional methods for producing the teeth on planetary spindles as follows: The production is widespread by milling and grinding. For this purpose, the contour of the toothing is determined and the cutter moves along the contour. The cutter works relatively coarse. Therefore, then a fine machining is common, for. B. by grinding externally toothed parts or by honing or eroding in internally toothed parts usual. There are also known forming processes for gear parts, which are casting and sintering. Forging processes include forging, pressing, drawing, rolling, stamping).

Milling is part of the machining process. Other machining methods include, for example, planing, beating, broaching, scraping, grinding, honing.

All manufacturing processes for toothing have in common that they follow the specified contour of the toothing. With normal gearing, a tooth changes with a tooth gap. The distance between two adjacent teeth of a part is the same When defining the contour, it depends on the toothing. The gearing follows the general knowledge of gear technology.

A distinction is made between different basic types of gears: involute toothing, cycloidal toothing and gear toothing. In addition, there are various special forms.

In planetary roller extruders, the involute gearing has prevailed. The involute toothing with full tooth stocking is referred to below as normal toothing.

In the involute toothing, the flanks of the teeth of the gear are formed by involutes. One can imagine the involute, if one imagines the gear base circle as a massive cylinder, around which a thread is wound. If this thread is now unwound, then the taut end point of the thread describes the figure an involute. All points on the thread, which have the integer multiple distance from the end point, thus move on the involute of another tooth. The involute gears have the following advantages:

The flanks of two meshing gears always touch, and in these points of contact they always have approximately the same speed. This ensures that the transmission of the rotational movement takes place with little friction.

At the same time the involute toothing allows the uniform transmission of torque through a constant translation.

It is insensitive to the shifting of the axes of the gears (distance between the axles).

It is easy to manufacture with standardized straight-line tools. With the same geometry of the tool gears with different numbers of teeth and different profile displacement are freely combinable.

With planetary gearboxes, as with other transmissions, it is endeavored to work with as little clearance as possible between the gearbox parts. The game can be considered when defining the contour. In planetary roller extruders usually a much larger game is provided. Also this game can be considered in the determination of the tooth contour.

In conventional gearing, a tooth of a tooth gap and a tooth space follows a tooth, the teeth and the tooth gaps are the same. Since the teeth engage in the tooth gaps and the intermeshing / meshing gear parts should have the same teeth, the tooth gaps include a mirror image of the teeth. In the design of the toothing according to the invention, however, the tooth gaps are different than with conventional toothing. In the above-described production of the toothing according to the invention, individual or several teeth are removed from existing gear parts for this purpose. Alternatively, even when determining the tooth contour, one or more teeth are removed. The production then follows in the manner described above the specified tooth contour according to the invention. That is, in the case of using a milling cutter, the milling cutter follows the predetermined new contour with larger tooth gaps. The same applies to other tools for producing the previously defined new contour.

It is advantageous if the number of teeth of internal housing teeth (bushing teeth), planetary spindles and central spindle is chosen so that the self-cleaning effect of the planetary roller parts is maintained. This is the case, for example, when the number of teeth on the central spindle and on the housing internal teeth (bushing teeth) is straight and the number of teeth on the planetary spindles is odd. Then the melt is in each space between two teeth by the penetrating teeth in the gap of other parts of the planetary roller extruder in motion.

The same conditions arise with odd numbers of teeth on the central spindle and housing internal teeth and even number of teeth on the planetary roller spindles.

The same result can be achieved by irregular removal of the Zahnbesatzes, for example, that not regularly every second tooth, but once or several times another tooth, for example, the third tooth is removed or, for example, two originally adjacent teeth remain untouched. That is, the processing takes place at different intervals. It may be sufficient that a distance is different than the other distances. It can also be different distances. The same result can also be achieved by combining planetary roller spindles machined according to the invention with unprocessed planetary roller spindles, or by combining the different types of planetary roller spindles machined differently in accordance with the invention.

The transport spindles and the associated prior art are described in DE 10 2006 033 089 A1 . EP1844917A2 . DE2702390A . EP1833101A1 . DE10142890A1 . US4981711 . GB2175513A . US5947593 . DE2719095 ,

Each planetary roller extruder has a maximum planetary spindle stock. This is the maximum number of planetary spindles that can be accommodated between the internal teeth of the surrounding housing and the central spindle, without the planetary spindles preventing each other from rotating.

The maximum planet spindle stock depends on the respective gear module.

While the planetary roller extruder module is an extruder section, the spline module is a design / calculation size determining the shape of the teeth and gullets.

By selecting a lower planetary spindle stocking compared to the maximum planetary spindle stocking, in addition to the use of transport spindles according to the invention, the energy input into the feedstock in the extruder can be reduced. Preferably, at least one reduction of the planetary spindle number is provided by one, optionally also by at least 2 or at least three compared to the maximum planetary spindle stocking.

There is the expectation that prevail planetary spindles, which are interlocked along the entire length according to the invention.

In certain cases, however, it may nevertheless be advantageous to use planetary roller spindles which have the above-described machining in the above-described range and are normally toothed in the remaining region or are formed as nubble spindles or have a different toothing.

This can be done by the processing tools terminating at the transition from one area to the other area. In combination with napping this means that the counter-teeth, which in the above-described form the nubs spindles, expire at the mentioned transition.

Likewise, processing progresses from one area to the other. The term of leakage is derived from the leakage of the gear tool. The gear tool penetrates namely between the ends of a planetary spindle not abruptly in the material, but slowly. The same applies if the gear tool is moved out of the material, d. H. expires. There are transition areas, which are referred to here as phasing out.

Alternatively, multi-part planetary roller spindles are provided, namely with a separately and according to the invention processed part and with a separately produced residual part. The remainder may be a knobbed part or a normal toothed part or another part. Both parts are also provided with a central bore for an armature, with which the two parts are braced together. On the way arise multi-part planetary roller spindles, which have a tooth change over its length, that is, change from a gearing according to the invention to another gearing.

The multi-part can have advantages in the production of the teeth by the parts are made with different teeth separately. Then the tools do not have to follow the change of teeth. In connection with a desired abrupt change of the gearing, such an approach offers itself.

On the other hand, procedurally, a slow change from one gearing to another can also be advantageous. A slow transition from one described above Toothing a standard toothing arises in the application of a milling cutter, for example, by the fact that the cutter used for the subsequent tooth removal is slowly moved out of the material of the planetary roller spindle.

It can also occur a change from a gearing, for example, from a normal gearing, to a gearing described above. Then, the same applies to the above-explained change with the proviso that for a slow change of the cutter is slowly driven into the material of the planetary roller spindle.

The multi-part planetary roller spindles can also have a multiple gear change.

There are also one-piece Planetwalzenspindeln into consideration, which show over its length in the toothing one or more tooth change.

For each change of the gearing, the statements regarding the subsequent removal of teeth and the previous definition of the tooth contour apply accordingly.

Depending on the nature of the elastomer, degassing may also be required. For the details, for example, reference is made to the following degassing operations:
DE 10 2004 061 185 A1 . DE 10 2004 060 966 A1 . DE 10 2004 053 929 A1 . DE 10 2004 005 00 58 A1 . DE 10 2004 004 237 A1 . DE69908565T2 . DE69827497T2 . DE69807708T2 . DE69725985T2 . DE69715781T2 . DE69715082T2 . DE69711597T2 . DE69710878T2 . DE69709015T2 . DE69707763T2 . DE69630762T2 . DE69628188T2 . DE69622375T2 . DE69428309T2 . DE69427539T2 . DE69419146T2 . DE69312852T2 . DE69312246T2 . DE69306874T2 . DE69207369T2 . DE68928567T2 . DE68915788T3 . DE60206271T2 . DE60012108T2 . DE19956483A1 . DE19954313A1 . DE10257377A1 . DE10356821A1 . DE10354546A1 . DE10354379A1 . DE10352444A1 . DE10352440A1 . DE10352439A1 . DE10352432A1 . DE10352431A1 . DE10352430A1 . DE10351463A1 . DE10349144A1 . DE10345043A1 . DE10343964A1 . DE10342822A1 . DE10340977B4 . DE10340976B4 . DE10333927A1 ,

The planetary roller spindles form only part of the planetary roller extruder. Other planetary gear parts are the central spindle and the internal toothing of the housing or the optionally seated in the housing socket.

The central spindle can also be provided with the toothing described above. The same applies to the internal toothing of the housing or the socket. In that regard, the above statements also apply to the central spindle and the internal teeth. Multi-part central spindles already belong to the known state of the art, so that the above-described machining of the central spindle is easier. Nevertheless, it is usually more advantageous for procedural reasons to provide the planetary spindles with the toothing according to the invention. The planetary roller spindles offer a larger toothing surface than the central spindle with a correspondingly large stocking number. As a result, the toothing according to the invention has a greater effect there than at the central spindle. In addition, there is the advantageous combination possibility of planetary roller spindles. As stated above, the planetary gear spindles provided with the above-described toothing can be combined with normally toothed planetary gear spindles. Optionally, the toothing described above is at the same time fully or partially studded. This is done by the opposite teeth described above in the nubs of the teeth remaining after the tooth removal.

The internal toothing of the housing can also be provided with the toothing described above. As with the central spindle, it is generally advantageous to provide the planetary roller spindles with the toothing according to the invention.

It is also conceivable to interlock all planetary roller parts together in accordance with the invention.

Advantageously, the extruders can be used not only for the crosslinking / vulcanization of artificial elastomers and natural elastomers (eg rubber), but also for the recycling of crosslinked elastomers or for devulcanization of rubber. This means that with the same system, it can be both cross-linked / vulcanised and devulcanized under different management conditions. It is possible to drive batchwise, d. H. make a batch of recycled material and then make a batch of product material or vice versa.

In larger factories, it may be convenient to use multiple plants, one of which is for cross-linking / vulcanization and another for devulcanization. The device for devulcanization is much smaller than the system for crosslinking / vulcanization, if only an admixture of recyclate to fresh material in a plant for product material is provided. If more than one equipment is intended for product material or is being produced in suitable containers in addition to the equipment for crosslinking / vulcanization, the Devulcanization plant to be identical or even larger than the equipment for crosslinking / vulcanization.

Rubber consists of natural rubber and / or artificially produced elastomers whose molecules have undergone crosslinking. Among others, sulfur-carbon compounds and sulfur-sulfur compounds between the molecules are known. It is also spoken of cross connections.

Crosslinking drastically changes the material properties. This relates in particular to the strength, elasticity and heat load capacity.

Predominantly rubber is used in the vehicle industry. The load capacity of vehicle tires is legendary.

Depending on the running kilometer of the tires results in a state of wear, which is measured by how much the profile of the tires is worn.

If the profile has fallen below a certain thickness, a tire change must be made.

It fall on old tires or old rubber.

Although there are various proposals for the chemical treatment of waste rubber, but the effort is so high that so far it is hardly used. Rather, waste rubber is preferably supplied to the combustion. The cement industry has proven to be a large buyer. There, the waste rubber in the rotary kilns is mitverbrannt. The cement rotary kiln has a long combustion section, so that unburned gases are burned. A burden on the environment from unburned gases of waste tire combustion is thus excluded.

However, the cement industry usually requires a waste disposal contribution for waste tire combustion.

The disposal of used tires is also no longer considered timely.

Therefore, efforts have been made for a long time to the recycling of rubber and elastomers. There are different ways.

After DE60004885T2 are used to devulcanize cured (crosslinked) elastomers and rubber modifiers. These modifiers consist entirely or partially of adipic acid or oxalic acid. Furthermore, find additives that consist of sulfur, zinc oxide and stearic acid. Further, attention is drawn to urea, dicarboxylic acid, toluene and xylene.

In the DE 909041 are provided as modifiers Edeleanuextrakte that are derived from petroleum processing. These are, for example, kerosene, nitrobenzene, furfurol, phenol, dichlorodiethyl ether,

The DE 60008279T2 For example, it provides amine compounds as devulcanizing / modifying agents. In addition, many other agents are mentioned in this document, with which the crosslinking of the elastomers can be processed. These include disulfide or Dphenyldisulfid, thiophenol, n-butylamine, octylamine, hexadecylamine, tri-cylamine, benzylamine, 4-piperidinopiperidine.

The EP 1435372 suggests 2-butanol and carbon dioxide as devulcanizing / modifying agents. Incidentally, the printed matter refers to various alcohols as devulcanization agents / modifiers.

Another method proposes for devulcanization, a treatment of the recyclate in a gas phase of air or composite with chlorine and fluorine.

The DE6021521812 provides aromatic oil, naphthenic oil or paraffinic oil as a devulcanizing agent.

The DE60306089T2 envisages 2-butanol and carbon dioxide as devulcanizing agents. Also the DE60120804T2 provides modifier. However, the oil is extracted from the recyclate itself.

Optionally, the invention also utilizes the devulcanizing / modifying agents. Their application requires, depending on the nature process temperatures between 150 and 350 degrees Celsius. However, the invention additionally proposes the treatment in a planetary roller extruder or planetary roller extruder section. As a result, the devulcanizing / modifying agents are pressed into the recyclate and, in addition to the emanating from the Devulkanisierungsmitteln / modifying agents strain of the molecular chains in the recyclate still a strong mechanical stress in the recyclate.

Preferably, the invention proposes to effect the devulcanization solely by mechanical and thermal loading of the elastomers in a planetary roller extruder or planetary roller extruder section.

From the point of view of the invention, the modifiers have the disadvantage that the modifiers remain wholly or partly in the recyclate and limit the usability of the recyclate very strong.

Although it is also known devulcanization without chemical means.

Microwaves and ultrasonic waves are preferably used.

The waves create a strong mechanical stress on the rubber and elastomers, which are intended to disrupt the molecular chains. The mechanical load can be supplemented by the application of heat or by high vapor pressure.

Nevertheless, this type of devulcanization is considered insufficient, cf. for example the DE60120804T2 ,

In the preferred application of extruder according to the invention for the recycling of elastomers / elastomers or rubber, another approach is taken.

The invention seeks - as far as possible - to destroy the cross-linking mechanically and / or thermally, at least partially, in the case of waste rubber and elastomers. In particular, the invention aims to recycle scrap rubber and elastomers whose crosslinking is based on a sulfur compound.

According to the invention, the mechanical and thermal stress is generated in a planetary roller extruder in that on at least one planetary roller extruder section / planetary roller extruder module in addition to the deformation of the elastomers between the meshing teeth of housing, planetary spindles and central spindle still a strong mechanical stress of the elastomers sm exit of the planetary roller extruder section / Planetwaltezene extruder module is generated.

The exit is usually defined by a stop ring on which the planetary spindles slide around the central spindle as they circulate. This thrust ring is dimensioned so tight that the through-pressed through the opening recycling material still undergoes the desired mechanical and thermal stress to break up the molecular chains.

The correct opening width of the thrust ring can be easily determined by replacing the thrust ring against rings with a small opening.

This is especially true for thrust rings in a planetary roller extruder section or planetary roller extruder module whose housing has a collar at the respective end and is clamped to the collar on a corresponding collar of the housing of a subsequent extruder section. Then the stop rings are usually clamped between the two section ends / module ends.

The thrust ring can also be designed in several parts or form a multi-part construction with other rings, so that one part shows particularly advantageous sliding properties for the Planetsprindeln and the other part of the construction forms the desired constriction.

Optionally, the stop ring can also have multiple functions. For example, the run-up ring can also be designed as a dispersing ring. Then found in the run-up ring or in the multi-part run-up ring design channels, which are used for the entry of process agents or additives for the elastomers.

As such, single screw extruders and twin screw extruders are known to cause mechanical stress that can disrupt molecular scaffolds. A corresponding prior art is in the DE60120804T2 as well as in the DE69329245T2 as well as in the DE69724239T2 described. For industrial devulcanization, these proposals are still insufficient.

In the case of planetary roller extruders, a much lower mechanical load on the molecular frameworks is also considered, compared to a twin-screw extruder, taking into account the deformation conditions on the thrust ring.

Even though the planetary roller extruders are referred to in some documents as a possible extruder variant, planetary roller extruders have hitherto not found an entry into production plants for the recycling of rubber and elastomers. The low expectation of the mechanical stress of molecular chains by planetary roller extruder corresponds to the fact that some references to the use of planetary roller extruders for the regeneration of rubber are at the same time connected with the reference to the addition of devulcanization agents described above.

The invention nevertheless builds with the narrowed stop rings for devulcanization alone sufficient mechanical effect in planetary roller extruders.

Usually, thrust rings have an inner diameter which is approximately equal to the diameter which the central axes of the planetary spindles describe. Various designs also show a larger inner diameter.

The thrust rings according to the invention preferably have an inner diameter which is at least 10% smaller, preferably at least 20% and even more preferably at least 30% smaller than the diameter of the orbit, which describe the planetary spindles in operation with their central axes.

The reduction of the passage cross-section can even go so far that the thrust ring engages in a groove of the central spindle.

In this case, for example, the stop ring can be left open only a gap of a few millimeters, in the extreme case of, for example, a millimeter, to the tooth base for the passage of rubber and elastomers.

According to the invention, it may be advantageous to incorporate the groove by a small amount, for example by the measure of one millimeter, on the tooth base of the teeth on the central spindle also in the central spindle.

The process according to the invention is used for recycling crosslinked elastomers or waste rubber, which is freed of metallic reinforcing inserts. Metallic reinforcing inserts occur, in particular, on scrap tires. These are steel inserts that hold the vehicle tires in the desired shape.

For the separation of rubber and metal, various methods are suitable.

Optionally, the waste rubber is strongly cooled and crushed in a highly cooled state in a mill. When chilled, comminution becomes easier because the compliance of rubber decreases. The colder the rubber, the easier the shredding becomes.

Preferably, the running surfaces of the scrap tires are peeled off. This recyclate is free of metallic reinforcing inserts and free of tissue deposits. The recycled material thus obtained is particularly suitable for the treatment according to the invention.

According to the invention, rubber and elastomers are used as chips in the extruder. The average chip diameter is preferably 5 to 40 mm, more preferably 15 to 30 mm.

In planetary roller extruder, the temperature of the material to be treated can be adjusted very well, because the material to be treated or rubber and elastomers is rolled over a large area and thin layers. As a result, the planetary roller extruder acts as a large-area heat exchanger. Single-screw extruders and twin-screw extruders of comparable size have a comparatively small heat exchanger surface.

The feed material is rolled thin-layered in the planetary roller extruder between the intermeshing teeth. This creates a strong kneading action on elastomers or on old rubber. Due to the kneading effect, heat is carried into the elastomers or the waste rubber.

The kneading effect can be influenced by different numbers and / or different design of the planetary spindles.

The number of planetary spindles is preferably at least 5, preferably at least 6. The larger the diameter of the central spindle, the more planetary spindles are usually provided in a module / section. For example, 24 and more spindles can easily be used for larger sizes.

The temperature of the treatment / recycling material is brought in the planetary roller extruder for supplying heat or by cooling to a desired level for recycling.

This level is according to the invention for treatment / recycling with sulfur binding between 200 and 350 degrees Celsius, preferably between 250 and 300 degrees Celsius.

The kneading action (including the deformation effect in the starting ring) and heat effect is maintained for a period of 1 to 4 minutes, preferably 1.5 to 3 minutes. This duration corresponds to the residence time in the planetary roller extruder.

In accordance with the invention kneading and heating of the waste rubber, the sulfur compound is blasted. The sulfur compound turns into a gaseous state. The gas is sucked off. At the extruder this is called degassing. For degassing, for example, a ring between two subsequent extruder sections or extruder modules is again suitable. This ring may in turn be a stop ring when it sits at the end of another planetary roller extruder section or planetary roller texture module.

The exact determination of the material-dependent respectively correct kneading effect and temperature can be determined by changing the cycle time and Change the temperature in a few experiments based on a few experiments.

With proper treatment or devulcanization, a fuzzy material without appreciable strength is produced after the appropriate duration of treatment / length of stay of rubber and elastomers.

If the temperature is too high, the material to be treated will visually show overheating, for example as a caking.

If the temperature is too low, the cross-linking will not be sufficiently removed; the discharged material, while flexible, will at least partially show its strength. With experience, operators can optimally set the extruder to recycle elastomers according to initial test results.

Depending on the material properties of the waste rubber, an extruder can be used whose length is sufficient to carry out the entire treatment / devulcanization in an extruder. That is, the extruder then has a length in which the entire desired residence time can be represented.

Preferably, however, find extruder application, which are composed of mutually aligned modules / sections.

The modules / sections optionally have all or part of a length of less than or equal to 800 mm, preferably less than or equal to 600 mm and even more preferably less than or equal to 500 mm.

Smaller lengths of individual or all modules / sections can be adapted to different temperature requirements. In addition, the temperature control on a longer extruder module / extruder section can also be subdivided into different sections which lie one behind the other in the axial direction.

But module lengths of more than 1000 mm, for example 1400 mm, can also be used.

The larger the diameter of the extruder, the larger the throughput usually becomes. As the throughput increases, the residence time of rubber and elastomers in the extruder may lengthen and result in a larger extruder length.

With the modular design / section design opened on planetary roller extruder and the possibility of changing the kneading effect by changing the teeth or by installing modules with different teeth.

As far as the same modules are already provided, a change in the kneading effect and cycle time can be achieved by replacing the plenum screws or by reducing the number of planetary spindles afterwards.

This involves a serious practical advantage when changing the input material. Favorable in the processing of rubber or the like elastomers and a different length of the planetary spindles, so that the fed into a planetary roller module material is taken gently and not abruptly total of the teeth.

Both the cross-linking of the elastomers and the recycling of the cross-linked elastomers can be carried out with an extrusion plant described above and different operations management.

The networking / vulcanization as well as the devulcanization can be done with the same system. Equally identical systems can be used, with a devulcanization system alone providing the feedstock for a single or multiple crosslinking / vulcanization equipment.

In this case, the devulcanization plant may also be larger or smaller than the crosslinking / vulcanizing plants if the demand for these plants is greater or smaller.

In the drawing, various embodiments of the invention are shown.

1 shows an extruder with the following components / sections: drive 1 , Move-in 2 , Planetary roller extruder sections 3.1 . 3.2 and 3.3 . 4 and discharge nozzle 6 ,

In the feeder 2 emits a dosage 8th , From the container 8th leads a dosing line into the feeder 2 ,

The dosage is filled in a manner not shown with sulfur-crosslinked EPDM particles from the recycling of used tires for its reprocessing and closed. These are particles that have accumulated during the peeling of the tread and after appropriate comminution.

The EPDM particles enter the feeder 2 and is conveyed from there in the extrusion direction. The extrusion direction has in the drawing from left to right.

The collection 2 is designed in modular design. This module has the construction of a single-screw extruder.

For Devulcaniseren of granular EPDM recyclate the following applies. In the feeder 2 a first warming takes place.

For the heating of the EPDM particles is a heating-cooling circuit 15 intended. The heating-cooling circuit 15 interacts with the housing shell of the module. The heat is transferred to the introduced EPDM particles via the housing jacket. In addition, it generates in the module 2 circulating screw heating of the EPDM particles.

The EPDM particles arrive in the exemplary embodiment with preheat temperature of 140 degrees Celsius in the next extruder section / module 3.1 , To the extruder section / module 3.1 close extruder sections / modules 3.2 and 3.3,4 , The modules 3.1 to 4 have the design of planetary roller extruders. The modules 2 . 3.1 . 3.2 and 3.3 . 4 have matched housing and not shown flanges, where they are connected to each other. The connection is a screw connection.

In the planetary roller extruder sections / modules 3.1 . 3.2 and 3.3 . 4 The EPDM particles are often kneaded between the rotating planetary roller spindles, the central spindle and the internally toothed extruder housing, so that always form new surfaces that can be used for heat transfer.

In this case, heat can be transferred from the housing jacket to the EPDM or withdrawn from the EPDM and removed via the housing jacket.

As in the module 2 are the modules 3.1 . 3.2 and 3.3 such as 4 with heating and cooling circuits 16 . 17 . 19 . 20 Mistake.

In the extruder sections / modules 3.1 . 3.2 and 3.3 The EPDM is brought to a temperature of 300 degrees Celsius, in the extruder section / module 4 to a temperature of 220 degrees Celsius. The heating and cooling circuits 16 . 17 . 19 . 20 ensure compliance with the desired temperature. In this case, heat is introduced into the EPDM by the deformation work of the extruder sections / modules. Insofar as the heat input is insufficient to reach the desired temperature, the missing heat is transferred from the heating cooling circuits via the associated housing jacket of the module to the EPDM. Insofar as the amount of heat generated by the work of deformation exceeds the amount of heat required for the desired temperature, the excess amount is withdrawn through the heating and cooling circuits.

In the extruder sections, the molecular chains of the EPDM are largely destroyed. The sulfur evaporates. The obtained and maintained temperature profile corresponds to the specifications of the EPDM manufacturer.

In other application examples, a different temperature is set and maintained.

In addition, in the exemplary embodiment for the processing of the EPDM, the possibility of injecting devulcanization / modifying agents is provided. The injection takes place via an injection ring 21 , The injection ring 21 is between the modules 3.1 and 3.2 intended. The injection ring 21 is connected via a line with a pump and a reservoir.

In the embodiment, the injection ring forms 21 the starting ring for the rotating planetary spindles of the module 3.1 ,

Further, on the injection ring 21 Provided openings in which sit pressure gauges and temperature gauges. These devices are integrated in the control of the heating and cooling circuits.

Because of the details of the injection ring 21 and its arrangement in the housing will be referred to the DE 197209161B4 ,

In the exemplary embodiment, as little as possible use is made of the possibility of injection in order to minimize the proportion of disadvantageous constituents in the recyclate.

Also on the modules 3.2 and 3.3 are contact rings 22 and 23 provided with which pressure measurements and temperature measurements as on the module 3.1 let carry out.

The EPDM is discharged from the extrusion plant at the temperature of 220 degrees Celsius. This is the module 4 on the outlet side with a round nozzle 24 provided with 20 mm diameter. The discharged EPDM is placed between chill rolls 25 cooled.

The embodiment according to 1a differs from the embodiment according to 1 by another cooling on the discharge. In the embodiment, the cooling for the EPDM consists of a simple water tank 26 ,

For further processing, this will be in the water tank 26 collecting granular recyclate dried and for retreading used worn tires or given in other processing or routes of use.

The embodiment according to 5 differs from the embodiment according to 1a through a degassing 27 and by an additional dosage 28 ,

The degassing 27 consists of a laterally flanged twin-screw extruder, which can be used to prevent melt discharge, but permits outgassing. Outgassing is effected by a suction draft applied to the twin-screw extruder. By degassing the gaseous cross-linking agent and other gaseous components are deducted.

3 schematically shows conventional planetary gear spindles 321 Planetary Roller Extruder These planetary roller spindles 321 form multi-flight screws, which extend with constant inclination over the entire spindle length.

The flights are shown in the drawing by oblique to the spindle axis extending lines.

The worm threads run in the side view from the right to the right, clockwise. The screws have a toothing on the outside. The corresponding mirror-image toothing is found on the central spindle of the planetary roller extruder section and the internally toothed surrounding housing, so that the planetary roller spindles 321 can mesh with both the Gehäusungszahnnung and with the central spindle.

4 shows known planetary roller spindles 322 which, on the one hand, follows the same screw flights as the screws / spindles 3 have. On the other hand, the spindles have at the same time left-handed grooves which intersect the right-handed worm threads. The left-hand grooves are marked with dashes in the 4 represented, which the 3 cross the known flights at right angles. This is shown with crossing lines. By the crossing grooves, the webs between the flights, which form the teeth of the teeth in cross-section, interrupted. The remaining between two interruptions teeth form a spiny / knob-like tooth. The many side-by-side spines / nubs are reminiscent of the spiky dress of a knot. This results in the name knob knurling. The interruptions are referred to as tooth gaps.

2 shows more planetary spindles 23 with a part 25 , which of the gearing after 3 is modeled, and with a part 24 , which of the gearing after 4 is modeled.

6 and 8th show a planetary roller spindle according to the invention for the use of a planetary roller extruder in the drying station of an EPDM treatment plant 60 ,

The planetary roller spindle 60 consists of two parts 61 and 62 , The part 61 corresponds to a conventional planetary roller spindle with full tooth stocking. In the exemplary embodiment, it is a planetary roller spindle with a pitch diameter of 34 mm, with an outer diameter of 42 mm and a diameter of 26 mm at the tooth root of Zahnbesatzes. In the embodiment, the part 61 a length of 200 mm. The total length of the planetary roller spindle 60 is 1000 mm.

This results in the part 62 a length of 800 mm. The part 62 defines the range of inventive design of the planetary roller spindle, part 61 defines the remaining area. In the part 61 has the spindle 7 teeth 64 , which are similar to threads, but with a very large slope on the planetary roller spindle outside. This is in the 8th shown.

In the part 62 are 3 teeth 64 been milled off. This is before a surface hardening of the teeth 64 he follows. The distribution of the remaining teeth is in 7 shown. There are still two teeth 64 side by side. To the other teeth results in a tooth gap.

The planetary spindles after the 6 and 8th are referred to as transport spindles, because they have a greater transport effect in contrast to the Noppenspindel.

However, it also shows that the work done by the transport spindles is surprisingly low. Accordingly, the energy input into the EPDM is low. This facilitates compliance with the temperature required for the EPDM temperature.

In the embodiments according to 1 . 1a and 5 it is an extruder with 70 mm housing diameter (based on the pitch circle diameter of the housing internal teeth). The maximum number of planetary spindles for stocking the modules 3.2 . 3.2 . 3.3 and 4 is 7. There are 6 planetary spindles of the type after the 6 and 8th intended for the processing of EPDM in each module.

In other embodiments, different planetary spindles are provided in the various modules. The differences may concern the number of "missing" teeth. The differences may also arise from the combination with spindles of other designs. The differences may also arise from the combination of different teeth on individual or all planetary spindles. At least one partially designed as a transport spindle planetary spindle is provided in the extrusion line.

9 shows a planetary spindle with a normal toothing 80 at one end, then an area 81 with a knob toothing and an area 82 with a reduced toothing as described above.

10 shows a planetary spindle with a normal toothing 85 at one end, then an area 86 with a knob toothing, then an area 87 with a reduced toothing and again a normal toothing at the other end of the spindle.

The length of the modules is 400 mm in the exemplary embodiments. In the exemplary embodiment, the planetary spindles have a shorter length, in some cases a different length.

Also the extruder after 1a has starting ring for the planetary roller extruder modules shown schematically. The details are in 11 shown. Dnaach are associated with two successively arranged modules housing 115 designated. At the ends facing each other, a housing has a collar 116 and the other housing a collar 117 , Both collars are made by means of several, evenly distributed around the circumference clamping screws 118 braced together.

The housing 115 have inside each an internally toothed socket 129 , The socket 129 and the housings 115 enclose a centrally located central spindle 119 and planetary spindles 110 , The planetary spindles 110 are gleichmmäßäß arranged on the circumference of the central spindle and run in case of operation due to a central spindle rotation in the housing. Due to their toothing, the planetary spindle mesh with the same toothing of the central spindle and with the same toothing on the inside of the bushing.

During operation, the planetary spindles push 110 of the left module in the view against a multi-part run-up ring construction. This construction includes a sliding part 112 and a centering 130 , The centering 130 ensures a flush arrangement of the housing 115 and positions the slider 112 , The planetary spindles slide on the sliding part 110 circulating the left module.

The planetary spindles 110 the right in the view module have in the operating case, not shown in the drawing distance from the slider.

In addition, an injector is attached to the run-up ring construction 114 connected. If required, liquid additives or extrusion aids are injected via the injector.

The sliding part surrounds the central spindle annularly.

The inner diameter of the sliding member is in the exemplary embodiment 15% smaller than the diameter of the orbit on which the planetary spindles revolve with their central axes in operation. It still remains a gap between the central spindle and the inner surface of the slider.

In other embodiments, a gap results from a difference in diameter of the sliding member to the orbit of the planetary spindle centers of 10 to 30%.

Through this gap and through the tooth gaps of the central spindle recycled material is passed through during operation. The associated mechanical stress complements the mechanical stress of the recyclate between the teeth of the planetary roller extruder parts. In addition, a heat load of 280 degrees Celsius in the embodiment, in other embodiments of 250 to 300 degrees Celsius.

The total load of the molecular chains of the recyclate is so great that the molecular chains break apart.

The accumulated recyclate can be reused in the above-described batch operation in the same facilities for the production of EPDM material for the retreading of used tires, but with a different operation of the system Unnecessary parts of the plant are shut down or dismantled. In particular, the above-described, provided for additional mechanical stress of the recyclate ring is dismantled. Additionally required components are mounted. This is especially true for the dosage of the recyclate and the fresh EPDM and the mixing proportions.

In the exemplary embodiment, the recycled material is mixed with fresh EPDM, wherein in the exemplary embodiment a recycled mix fraction of 20%, based on the total mixture, is provided. In other embodiments can be run with a much higher proportion of recycled mix. In some cases, you can only use recycled material. Furthermore, the EPDM is given up together with other substances, in particular crosslinking agents, optionally also accelerators or retarders. Because of the other substances / mixture proportions of EPDM, reference is made to the following publications:
DE 60 2004 010 70 T2 . DE 60 2004 009 315 T2 . DE 60 2004 008 907 T2 . DE 60 2004 008 245 T2 . DE 11 2008 000 757 T5 . DE 11 2006 001 824 T5 . DE 10 2007 050 875 A1 . DE69921863T2 . DE69915532T2 . DE69915008T2 . DE6r9913373T2 . DE69906484T2 . DE69823091T2 . DE699813587T2 . DE69811151T2 . DE69729856T2 . DE69725916T2 ,

In the task of mixing proportions is favorable when all the other mixture proportions of the EPDM are first brought into mixture before the crosslinking agent is introduced into the extruder. Liquid and gaseous cross-linking agents can be injected directly in the manner described above. Solid crosslinkers can be added via a side arm extruder. It is advantageous if the solid crosslinking agents are registered with a liquid mixture fraction. This reduces friction and facilitates the mixture.

In the exemplary embodiment, the crosslinking temperature is 170 degrees Celsius. As long as the temperature in the extruder is sufficiently below the crosslinking temperature, the mixture can be processed very easily. With the above-described temperature control of the extruder, the temperature in the extruder can be easily controlled. In the exemplary embodiment, the temperature of the extruder is maintained at 145 degrees Celsius. In the exemplary embodiment, the extrusion plant is followed by a mold. Therein, the embodiment differs from the devulcanization systems explained above.

For retreading the previously peeled-off scrap tires is brought into the mold. It remains between used tires and mold inner wall a shaping cavity. In the shaping cavity, the hitherto uncrosslinked mixture is brought, which has been brought shortly before the end of the extruder to crosslinking temperature, so that in the form of crosslinking / vulcanization and compound of the introduced material can be done with the old tire.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been 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.

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• DE 69725916 T2 [0217]

Claims (21)

Processing of elastomers in a planetary roller extruder or in a planetary roller section with an externally toothed central spindle, on the central spindle revolving toothed planetary roller spindle and an internally toothed, surrounding housing, the planetary gear spindles simultaneously with the central spindle toothing with the housing toothing, the toothing is a helical toothing, so that the individual teeth run like screw threads on the toothed surfaces according to the pitch of the teeth to the extruder longitudinal axis, in particular with an involute toothing, in which a) at least one planetary roller spindle and / or central spindles and / or Gehäuseverzahnungen be used on which at least one tooth, but not all teeth has subsequently been wholly or partially worked out and / or b) Planetwaren spindles and / or central spindles and / or Gehäuseverzahnungen be used, the teeth have been prepared for a fixed tooth contour of planetary spindles and / or central spindles and / or Gehäuseverzahnungen, wherein the tooth contour is equal to a toothing with subsequently wholly or partially worked out teeth. A method according to claim 1, characterized by increasing or reducing the number of planetary spindles with reduced tooth stocking to improve the extrusion result. A method according to claim 1, characterized by the use of a set of sections together extrusion plant, wherein at least two, preferably at least three planetary roller sections are provided. Method according to one of claims 1 to 3, characterized in that the planetary roller extruder or planetary roller section for recycling crosslinked / vulcanized elastomers is at least partially driven at a temperature at which the molecular chains undergo a sufficient for reuse by the thermal and mechanical stress. Method according to one of claims 1 to 4, characterized by the generation of additional mechanical load for the recyclate by incorporating at least one ring which surrounds the central spindle in the installed state and leaves a flow area free, which is smaller than the flow area at the stop ring. A method according to claim 4 or 5, characterized by additional addition of devulcanization in the extruder. A method according to claim 6, characterized by adding additional devulcanization means between the first and second planetary roller sections. A method according to claim 7, characterized by an addition of liquid or gaseous devulcanization agent via an injection ring. Method according to one of claims 1 to 8, characterized in that the gaseous constituents released in the extruder are withdrawn. Process according to any one of claims 3 to 9, characterized in that the elastomers are loaded with a sulfur compound between the molecules for a period of 1 to 4 minutes at a temperature of 200 to 350 degrees Celsius to destroy the molecular chains. Process according to Claim 10, characterized by kneading the recycled material for a period of 1.5 to 3 minutes. A method according to claim 11, characterized in that the kneading of the recyclate is carried out at a temperature of 200 to 350, preferably at 250 to 300 degrees Celsius. Method according to one of claims 4 to 12, characterized by the use of a planetary roller extruder, which is composed of at least two planetary roller extruder sections / modules, in particular of three sections / modules is put together, wherein between at least two sections of the additional mechanical stress causing ring is provided , A method according to claim 13, characterized by the use of a ring, which is at the same time thrust ring or part of a stop ring construction, wherein the stop ring has an inner diameter which is smaller than the diameter of the orbit on which the center axes of the planetary spindles rotate about the central spindle, said Diameter difference is at least 10%, preferably at least 20% and even more preferably at least 30% of the pitch circle diameter of the planetary spindles. A method according to claim 13 or 14, characterized in that a stop ring is used whose inner diameter is smaller than the outer diameter of the central spindle, wherein in the central spindle a groove for the passage of the extruded rubber and the elastomers is provided, whose free passage cross-section is smaller, preferably at least 10% smaller, more preferably at least 20% smaller than the passage cross-section formed by the gaps between the teeth of the central spindle, when the inner diameter of the stop ring is equal to the outer diameter of the central spindle. A method according to claim 15, characterized by the use of a stop ring, which consists of at least two parts, preferably two halves, so that the stop ring can be assembled around the central spindle around. Method according to one of claims 1 to 16, characterized by using a planetary roller extruder, the planetary spindles consist at least partially of hedgehog spindles or Noppenspindeln. Method according to one of claims 1, 2, 3 and 17, characterized by the task of recycled material in a planetary roller extruder or an extruder with a Planetewalzenabschnitt in mixture with fresh elastomers and with other mixing proportions, in particular with crosslinking agents, for the production of elastomeric products. A method according to claim 18, characterized by using a structurally identical extruder as in the devulcanization, wherein unused parts are still set or disassembled and / or additional parts are mounted. A method according to claim 19, characterized in that the kneading action in the extruder and the duration of residence are adapted by replacement of planetary spindles. Method according to one of claims 18 to 20, characterized in that the mixture is fairly brought to the extrusion immediately subsequent shaping only at the end of the extruder to crosslinking temperature, so that the crosslinking takes place in the forming tool.

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