WO1996038496A1

WO1996038496A1 - Process, reactor and device for decomposing elastomers

Info

Publication number: WO1996038496A1
Application number: PCT/EP1996/002328
Authority: WO
Inventors: Uwe-Falko Kuhn; Volker Roth; Helmut Guido Alt
Original assignee: Projekt-Entwicklungs-Zentrum In Thüringen (Pez) E.V.
Priority date: 1995-05-30
Filing date: 1996-05-30
Publication date: 1996-12-05
Also published as: DE19519793A1; DE19519793C2

Abstract

A process and device are disclosed for decomposing elastomers, in particular rubber elastomers, by the action of oxygen and solvents. The optionally comminuted elastomer-, in particular rubber-containing starting materials are exposed to a gaseous mixture of 0.5 to 5 % by volume ozone and 99.5 to 95 % by volume oxygen and to at least one alkaline substance in an aqueous and/or organic solvent, optionally in the presence of a phase transfer catalyst. The alkaline substance is selected in the group of alkali metal hydroxides, alkaline earth metal hydroxides and ammonium hydroxides. The alkaline solution is applied on the starting materials in the presence of ozone through nozzles, at least temporarily under a high pressure from 1 x 106 to 5 x 107 Pa (10 to 500 bars), in particular from 1 x 106 to 1 x 107 Pa (10 to 100 bars).

Description

'Process, reactor and device for degrading elastomers'

description

The invention relates to a method and a reactor and a device for degrading elastomers, in particular rubber elastomers.

In the manufacturing industry, production and

Sales of profitable items by-products that cannot be marketed for the company's financial benefit. On the contrary, the disposal and removal of the "waste" incurs costs in waste incineration plants or landfills, which is constantly increasing due to the shrinking landfill space. Unfortunately, the manufacturing companies often forget that industrial waste is partly high-quality and expensive material, the incineration or disposal of which is a waste of high-quality raw materials. The same applies if the items sold first are used and worn. In the future there will be more and more that the industry will be obliged to take back old products and to recycle them, better one

Recycling. Therefore, there is an urgent need to look for new waste recycling processes that can result in products that can be marketed again. This creates opportunities to further reduce the consumption of natural resources and reduce environmental pollution.

In particular, there is a need for new processes with which elastomer waste can be processed. In this context, processes for reprocessing old car tires, tubes and sealing materials are to be mentioned.

Seals with rubber elastomers as binders are flat after the Calender or paper process manufactured and then punched into flat seals. This creates very large amounts of waste (up to 70%). These wastes have a composition of 8-12% aramid pulp fibers, approx. 25% rubber and the rest fillers and optionally vulcanization aids. Grinding up this waste and returning it to the production process is not possible because of the large quantities and the deterioration of the product. Disposal is becoming increasingly difficult due to increasing landfill fees, so that there is a need for regeneration.

The same problem arises in the case of used tires, where a possible recovery of the rubber material in a form which enables the vulcanization, albeit to products of poorer quality, is interesting.

Tires, like other rubber and rubber-like products, become brittle and brittle after a certain period of time. Main cause of natural

The aging process under the given atmospheric conditions is an aggressive gas that is always present in traces - the ozone. This was the starting point for the development of a process in which the process described above is accelerated by increasing and controlling the amount of ozone and adding various other substances. The aim is to use the

Ozone technology to oxidatively split the sulfur bridges and to crack the C = C double bonds still present in the macro molecules.

The basic principle of the course of the reaction of the cleavage of olefinic double bonds has been known for some time. It was postulated by Harris in 1904 and confirmed by Staudinger and Pummerer:

So far, however, the application has only been limited to determining the constitution of alkenes when using small amounts of substance. The main problem is the formation of dangerous ozonides. DE-A-34 20 609 shows a separation process for rubber and components wholly or partly enclosed therein by means of liquid or vaporous mineral oil at 180 ° C.-320 ° C., which is applicable for the recycling of used tires.

EP-B-0 165 585 also shows a process for recycling used tires

Rubber separation using heated liquid solvents.

EP-A-0 074 344 shows the recovery of rubber by using a plasticizer and possibly a peptizer under the action of oxygen at 130-200 ° C.

EP-A-0 006 834 shows the rubber recovery by chemical oxidation processes under the influence of oxygen at approx. 100 ° C.

U.S. 4,426,459 B1 describes a process for the degradation of rubber with

Using organic hydroperoxides in the presence of air or oxygen. An alkaline compound may also be present. As mentioned, the active compound according to U.S. 4,426,459 B1 a hydroperoxide. Since it is generally known that peroxides are not as reactive as ozone and do not have a wetting effect, this process has a relatively poor degree of efficiency.

U.S. 5,264,640 B1 describes a process for the degradation of tires and other rubber materials using a so-called "dry process". There, ozone is used in quantities of 0.01% by weight. The person skilled in the art knows that this low ozone concentration must not be increased because of the risk of ozonides being formed, since otherwise there is a justified risk of self-ignition in the dry silos.

From the U.S. 4, 161, 464 B1 a process for the devulcanization of rubber is known, a phase transfer catalyst also being used, among others.

DE-OS 25 20 598 describes a regeneration process for waste rubber, the materials to be treated are placed in a heatable autoclave and the old rubber is broken down under pressure.

However, all of the above-mentioned processes have the disadvantage that the degradation does not take place 100% and that the additives, fillers and reinforcing materials contained therein have to be removed beforehand and these materials are not recycled.

It is therefore an object of the invention to provide a process for working up (rubber) elastomers, in which at the same time still contains

Additives, fillers or reinforcing materials, metals and optionally vulcanization aids can be recovered. Furthermore, a reactor for the degradation of elastomers, in particular for carrying out such a process, is to be provided, which guarantees an effective recovery of a starting material and which permits continuous or discontinuous operation.

This object is achieved by the features of claims 1 or 2 or 12 or 23.

Advantageous refinements are the subject of the dependent claims.

The invention therefore relates to a process for working up elastomers which is characterized by the action of ozone and at least one alkaline substance from the group alkali metal hydroxide, alkaline earth metal hydroxide, ammonium hydroxide (alkaline ozonolysis). Through ozonolysis, the C = C double bonds in the elastomer are cracked and the S-S bridges which may be present are cleaved oxidatively.

All those with a relatively high level are suitable as the starting material

Have elastomer content. These are, for example, old tires, sealing materials (in particular flat sealing materials, high-pressure sealing plates, cylinder head seals and their stamping residues) and the like. As starting materials are to be mentioned further: natural rubber or polymers containing C ₄ -C _β -conjugated diolefins, in particular vulcanized rubber or vulcanized polymers containing C ₄ -C ₆ -conjugated diolefins. The polymers can preferably be selected from the group: polybutadiene, polyisoprene, isobutylene-butadiene polymer, isobutylene-iosprene polymer, isobutylene-piperylene polymer,

Isobutylene-dimethylbutadiene polymer, polymer made from isobutylene and a C ₄ -C _β conjugated diolefin, brominated or chlorinated polymer from isobutylene and a C ₄ -C ₆ conjugated diolefin, isobutylene-isoprene-divinylbenzene polymer, isobutylene-isoprene-2.5 dimethyl-1,5-hexadiene polymer, polymer of a C ₄ -C ₆ conjugated diolefin and a vinyl or vinylidene-substituted aromatic

Hydrocarbon or polymer of a C ₄ -C ₆ conjugated diolefin and a C ₃ -C ₅ unsaturated nitrile group-containing monomer.

The degradability depends on the type of elastomer and can be up to 100%.

The rate of the reaction is in the range from 5 to 240 minutes, preferably between 10 and 30 minutes.

The waste material, i.e. Tires, inner tubes, seal waste and the like can be added unchanged or as a ground solid, depending on the size.

Alkaline ozonolysis is preferably carried out in a liquid medium. This medium can be aqueous or an organic solvent such as hexane,

Xylene, benzene, phenol, toluene or chloroform, isopropanol, acetone or mixtures of the aforementioned solvents. The pH of the medium should be in the range of 8-1 2, preferably around pH 10. A sodium hydroxide solution or a calcium hydroxide solution has proven to be most suitable, in particular in the concentration range from 1 M to 5 M. The higher the concentration of the alkali, the better the solubility and stability of the ozone. In a preferred embodiment, a sodium hydroxide / toluene solvent mixture is used. The gas stream used for ozonolysis contains 0.5 to 5% by volume of ozone and 99.5 to 95% by volume of oxygen, preferably 1% by volume of ozone and 99% by volume of oxygen.

According to a first embodiment of the invention, the liquid medium is in

Presence of the ozone mixture and a phase transfer catalyst applied to the starting material through nozzles, at least temporarily, under high pressure of 1 x 10 ⁶ up to 1 x 10 ⁷ Pa (10 up to 100 bar).

According to a further embodiment, the liquid medium is applied to the starting material in the presence of the ozone mixture under high pressure of 1 × 10 ⁶ to 5 × 10 ⁷ Pa (10 to 500 bar). Optionally, a phase transfer catalyst can be added to improve the solvent / waste lastomer contact. According to one embodiment, the addition of a catalyst is not absolutely necessary, since the waste material is already mechanically destroyed or cut up by the very high pressure, so that the use of the phase transfer catalyst is unnecessary.

In order to improve the contact between solvent and waste elastomer, especially in the case of purely aqueous solvents and in the lower pressure range, the use of a phase transfer catalyst is provided according to the invention. Tertiary ammonium salts or phosphonium salts, e.g. Tetrabutylammonium iodide, bromide, chloride, hydroxide or tetrabutylphosphonium chloride. The ratio of catalyst to waste material to be processed should be in the order of 1: 3 to 1: 8, preferably 1: 5, very preferably 1: 4.

The fission products produced during the decomposition reaction depend on the type of elastomer and must be removed from the circuit quickly due to the risk of further oxidation by the ozone. The remaining, unreacted residues of the starting material are returned to the circuit at a suitable point. The sulfur contained in the elastomer of the starting material is oxidized to sulfate by the oxidative treatment and can with Counterions are precipitated as salt, for example with milk of lime as calcium sulfate.

The ozone lysis preferably takes place at a temperature of -60 ° to 35 ° C, preferably between 10 and 25 ° C, preferably around 20 ° C, i.e. at room temperature instead.

The reinforcing materials, additives or fillers or metals, preferably in the form of alloys, contained in the waste material are removed from the reaction vessel after the elastomer has been degraded, cleaned and recycled. For example, reinforcement, additives or fillers may be mentioned: aramid, Twaron or Kevlar fibers, and the like.

The organic reaction products formed in the process according to the invention are separated off and investigated by means of gas chromatography and mass spectrometry.

According to the invention, there is provided a reactor for the degradation of elastomers, in particular for carrying out the method according to the invention, which comprises: a receiving device, in particular a container, to which an optionally comminuted starting material containing the elastomer or elastomeric rubber is fed; a first supply device which supplies an alkaline substance; a second supply device which supplies ozone; the receiving device, in particular the container, the first feeding device and the second feeding device being arranged in such a way that the starting material fed to the receiving device, in particular the container, or the starting material conveyed with or through the receiving device is exposed to the ozone and the alkaline substance is. Thus, according to the invention, an advantageous mixing or wetting of the starting material, which contains in particular the elastomer to be recovered, the alkaline substance and the ozone is ensured, whereby the

Recovery can advantageously be carried out quickly and effectively.

In the reactor, the first feed device, the alkaline sub- stampable at a high pressure of 1 x 10 ⁶ to 5 x 10 ⁷ Pa (10 to 500 bar), preferably from 1 x 10 ⁶ to 1 x 10 ⁷ Pa (10 to 100 bar) onto the starting material, the first feed device preferably comprises a nozzle, in particular a flat jet nozzle for supplying the alkaline substance. This type of supply of the alkaline substance achieves a particularly advantageous wetting, the starting material, in particular comminuted, being able to be whirled up by the alkaline substance.

In a preferred embodiment of the reactor according to the invention, the

Receiving device, in particular the container movably or displaceably or rotatably mounted and preferably driven by a drive. Furthermore, the alkaline substance can preferably be fed to the starting material eccentrically with respect to the center line of the reactor. Very good mixing of the reagents, in particular the starting material, the alkaline substance and the ozone, is thus further achieved, which makes recovery of the elastomer contained in the starting material particularly efficient.

The container is preferably removable from the reactor and comprises a bottom which has pores which preferably have a diameter of 50 to 300 μm, preferably 70 to 200 μm, and particularly preferably approximately 100 μm. It is thus possible to filter the wetted starting material, as a result of which the materials to be recovered can be separated from the residues, the residues being easy to remove from the reactor.

In a preferred embodiment, a housing is provided which has a lower part and an upper part, the lower part and / or the upper part preferably being removable. This is an advantageous opening of the reactor, in particular for maintenance work and for introducing starting material into the

Container possible.

The upper part further preferably comprises a central part and a cover, wherein the middle part is preferably essentially made of glass and the lid is preferably made essentially of stainless steel. It is thus possible to observe the inside of the reactor without having to remove the ozone from the reactor in order to be able to subsequently open the reactor.

The lower part is preferably fixed and the second feed device is attached to the lower part. The reactor formed in this way has an advantageously simple and therefore inexpensive construction.

A compressed air connection is particularly preferably provided for removing the

Ozone from the reactor. The ozone can thus be removed quickly in order to be able to open the reactor, as a result of which the opening processes can be accelerated and the corresponding amount of work, in particular the amount of time, can be reduced.

A temperature control device is preferably provided for setting a predetermined or predeterminable temperature inside the reactor, the temperature preferably being between -60 ° C. to 30 ° C. It is thus advantageously ensured that the reactions can be carried out at an advantageous temperature, as a result of which the recovery efficiency or performance is substantially increased.

A discharge device is advantageously provided in the reactor for discharging the treated starting material as an ozonized regenerate. The ozone supplied by the second feed device is particularly preferably part of one

Gas mixture, the gas mixture containing 0.5 to 5% by volume of ozone and 99.5 to 95% by volume of oxygen.

In particular, a filter device is provided which filters out the ozonized regenerate, the reaction solution filtered by the ozonized regenerate by filtering being fed to the container through a line. It is thus possible to reuse and reuse the reagents, thereby reducing the cost of recovering components of the starting material can advantageously be lowered.

Furthermore, the supplied ozone is preferably generated in an ozonizer, with a line being particularly preferably provided which returns the ozone or gas mixture supplied through the second supply device to the ozonizer. As a result, continuous operation of the reactor is possible in particular. Furthermore, the costs of recovery are further reduced and the risk of ozone being released due to the closed cycle in particular is reduced.

A mixing device is preferably provided which supports the mixing of ozone, alkaline substance and starting material, preferably in the receiving device or in the container, the mixing device preferably comprising a screw conveyor or two counter-rotating screw conveyors. An advantageously efficient degradation of elastomers is thus possible, since a particularly efficient mixing of the reagents is guaranteed.

In a further preferred embodiment, the container is divided into at least two container sections by at least one valve device, as a result of which the supply of the alkaline substance can advantageously be separated from that of the ozone.

Furthermore, according to the invention, a device is provided for the degradation of elastomers, in particular for carrying out the method according to the invention, which comprises: a reactor, in particular according to the invention; a separator which separates the regenerate from the reaction solution; a storage container for an alkaline substance, wherein a first feed device supplies the alkaline substance to the reactor. The device or circuit of devices according to the invention thus advantageously allows continuous or discontinuous degradation of elastomers.

A line is preferably provided in order to feed the reaction solution separated off in the separator to the reactor, the reaction solution in particular can preferably be introduced or can flow into a buffer container which is arranged between the separator and the reactor, the reaction solution stored in the buffer container being able to be fed to the reactor. In particular, the separated reaction solution is fed to the reactor by means of a pump, preferably a high-pressure pump. An advantageous circuit is thus provided, which ensures a reliable supply of the reaction solution, in particular during the continuous operation of the device.

The storage container for an alkaline substance preferably has an agitator device, which is preferably driven by an agitator drive. This ensures good mixing of the alkaline substance and, in particular, at least partially prevents phase separation.

In a preferred embodiment, a first metering pump supplies hydrochloric acid from a first storage canister to the storage tank, and furthermore a feeding pump prefers the alkaline substance from a second storage tank to the storage tank. It is thus possible to supply external substances, in particular to replace or replenish used reagents.

In particular, an ozone destroyer is provided to destroy the ozone emerging from the reactor, a third metering pump preferably supplying chemical substances from a third supply can to the ozone destroyer. This means that the existing in the circuit or in the device is destroyed

Ozone advantageously possible, e.g. for ventilating the entire device or system, in particular for maintenance work.

The invention will now be further described, for example, using figures of preferred embodiments and examples.

1 is a sectional view showing an embodiment of the reactor according to the invention; Fig. 2 is a sectional view showing another embodiment of the reactor according to the invention; Fig. 3 is a schematic view which is an embodiment of the device according to the invention.

1 shows an embodiment of the reactor 10 according to the invention. The reactor 10 comprises a container 50 in which a starting material E is introduced. The starting material E can in particular be comminuted or ground, which ensures better mixing with substances to be added. A first feed device 30 feeds an alkaline substance, which is in particular a preferably highly concentrated sodium hydroxide solution. The alkaline substance is in particular passed through a flat jet nozzle 34 at at least temporarily a high pressure of 1 × 10 ⁶ to 5 × 10 ⁷ Pa (10 to 500 bar), preferably 5 × 10 ⁶ to 1 × 10 ⁷ Pa (10 to 100 bar), most preferably at about 5 x 10 ⁶ Pa (50 bar), the supply being the alkaline

Substance preferably occurs eccentrically in the container, i.e. that the feed device 30 is arranged at a distance from the center line ML of the reactor 10. The alkaline substance is distributed over a limited area by means of the flat jet nozzle 34, in an amount of up to about 200 L / h. The flat jet nozzle 34 is preferably oriented in such a way that, in particular as a function of the particle size, the starting material E is whirled up.

The container 50 is preferably rotatably mounted in the reactor 10 by means of a suspension 13 and is rotated by a drive 60. The drive 60 comprises a drive motor 62, a gear 64, which a conversion or

Reduction of the rotational speed allows and in particular deflects the rotational movement in a direction adapted to the reactor, and a drive shaft. The container 50 can thus be rotated at a predetermined or predeterminable, in particular variable, angular speed of 0 to 54 revolutions per minute.

A second feed device 20 is also provided in the reactor 10 for feeding ozone. The second feed device 20, in particular in The shape of a nozzle is arranged in particular in a lower, in particular stationary, region of the reactor 10. The second feed device comprises a pressure connection 22, which is provided for connecting the feed device 20 to an ozone delivery device (not shown), in particular an ozonizer.

The reactor 10 has, in particular, a housing which can have a lower part 12, a central part 14 and a cover 16. The various elements of the reactor are preferably made of stainless steel, polytetrafluoroethylene (PTFE) or glass, the central part 14 preferably being made of essentially glass, which advantageously enables the processes inside the reactor 10 to be observed. The middle part 14 is preferably connected by flanges 14 'and 14 "to the lower part 1 2 or the cover 1 6, seals 15 being provided for sealing the connections. The lower part or the reactor base 12 and the cover 1 6 are formed from a material that is resistant to organic solvents and lye, preferably stainless steel or PTFE.

The first feed device 30 is preferably provided on the lid 16 of the housing, the connection being provided flexibly and / or removably in order to be able to remove the lid 16 from the central part 14. Furthermore, an aeration device 40 with a connection 42 is provided on the cover 16 for venting the reactor 10, for example when opening.

The second feed device 20 is preferably provided on the lower part 12, which is preferably fixed, as a result of which a good penetration of the starting material E, in particular in the form of granules, with ozone is ensured from below.

In another embodiment according to the invention, a third feed device can also be provided on the lid 16 of the housing. This means that ozone can also be introduced from the cover part. If appropriate, the feed device 20 provided in the lower part can then be closed. The container 50 is in particular designed as a filter basket which has pores with a diameter of 50 to 300 μm, preferably 70 to 200 μm, and particularly preferably approximately 100 μm. The filter basket is preferably made of steel and is preferably detachably fastened and can therefore be removed if necessary, in order in particular to easily remove residues from the container

Allow 50.

The reactor 10 also preferably has a connection for compressed air or an inert gas or gas mixture in order to e.g. before opening the reactor 10 to remove it. Furthermore, a drain device

70 is provided with a connection 72, which serves to drain the ozonized regenerate, which is mixed with the alkaline substance.

In an embodiment that is not shown, a mixing or mixing device is provided which contains the starting material, some of which is is wetted with the alkaline substance and permeated by the ozone, in particular mixed to a greater extent. The mixing device can be a rod which hangs from the fixed cover and has a mixing device plate at the end remote from the cover. The mixing device plate is substantially perpendicular to the movement of the starting material in the

Container arranged and causes a mixing or circulation of the starting material mixed with the alkaline substance and / or ozone. However, the mixer plate can be of a self-curved shape, e.g. have a propeller-like shape.

In the further embodiment of the reactor 110 according to the invention shown in FIG. 2, a container 150, 150 'is provided, in which a starting material is fed through a starting material supply device 152'. Furthermore, a first feed device 130 is provided, which feeds an alkaline substance to the container. The ozone or ozone-oxygen mixture formed in an ozonizer 122 is fed to the container 150, 150 'through a second feed device 120, specifically in a lower region thereof. The container 150, 150 'is preferably divided into two areas by a valve 154' divided, namely into an upper container 1 50 and a lower container 1 50 '. In the container 1 50, 1 50 ', preferably in the lower container 1 50', a mixing device 1 60 'is provided, which in particular comprises a screw conveyor or two counter-rotating screw conveyors. The valve 154 'serves in particular to subdivide the container 1 50, 1 50' if the starting material is to be brought into contact with the alkaline substance and the ozone in two successive steps.

Adjacent to the upper region 1 50 of the container 150, 1 50 'there is a discharge device 1 24' for discharging unused ozone or a gas mixture containing ozone, which is returned to the ozonizer 1 22 for reuse.

In the lower area 1 50 'of the container 1 50, 1 50' there is a discharge device 140 'for discharging the ozonated regenerate R. The discharge device 140 'comprises in particular a filter device 144' which has pores with a diameter of 50 to 300 μm, preferably 70 to 200 μm, and particularly preferably approximately 100 μm. Furthermore, a return device 142 'is provided, which returns the filtered reaction solution to the container 1 50, 1 50' in order to reuse it. The regenerate R present in the filter device 144 ', which has been separated from the reaction solution, is continuously discharged from the filter device 144' or removed discontinuously.

In order to interrupt the supply of the regenerate R to the filter device 144 ', e.g. if you want to remove the regenerate R from the filter device 144 ', a valve device 146' is provided in the lower region 150 'of the container 150, 150'. In an embodiment that is not shown, on the other hand, a discharge device is provided for the continuous discharge of the regrind, as a result of which the reactor is also suitable for the continuous region.

FIG. 3 shows a preferred embodiment of the device according to the invention for the degradation of elastomers. The device comprises a reactor B1 according to the invention, in which an elastomer-containing starting material is brought into contact with an alkaline substance and ozone. The reactor B1 preferably comprises a container 250 for receiving the starting material, a first feed device 230 for feeding the alkaline substance, in particular by means of a high-pressure nozzle 234, and a second feed device 220 for feeding the ozone.

The ozone is preferably generated in an ozonizer X1, to which oxygen is preferably fed and in which ozone is generated in particular by high-voltage discharges. The ozonizer X1 is preferably cooled by cooling water with a flow temperature of 20 ° C., which is tempered either by an air cooler or by a refrigerator.

The container 250 is preferably rotatably mounted in the reactor B1 and driven by a motor 260. Further features of the reactor B1 are preferably those which have been described in connection with the embodiments shown in FIGS. 1 and 2.

Furthermore, a drain direction 270 is provided, which ozonizes

Regenerate feeds a preferably lying separator B2 from the reactor B1. The drain device 270 is preferably arranged in a lower region of the reactor B1.

The regenerate is separated in the separator B2 at an extremely low flow rate, in particular of about 0.003 m / s, as a result of which good separation is achieved. In order to separate a low proportion of light phase, in particular from an organic phase, the separating mirror is placed in a narrow dome B2D of the separator. The light phase on the constricted dome B2D can thus be subtracted, in particular discontinuously.

In a special embodiment of the invention, an online Check the organic phase in the separator B2 or in front of the separator B2 in the drain device 270 to determine the degree or the completeness of the elastomer degradation. This online check can be carried out by means of suitable devices, for example by means of IR spectroscopy.

Furthermore, a template B4 for the alkaline substance is provided in the device. The alkaline substance is fed from the template B4 via the first feed device 230 into the reactor B1. For this purpose, a connection line is provided between the first feed device 230 and the template B4 and / or the separator B2. A buffer container B3 for the alkaline substance is preferably provided between the separator B2 and the reactor B1, and a high-pressure pump P1 preferably ensures the supply of the alkaline substance to the first supply device 230 under high pressure. The buffer container B3 preferably has a pH sensor F3.

A heat exchanger W1, in particular a stainless steel ring cooler, is provided thermally coupled to the template B4, which the heat generated in the template B4, e.g. by dissolving soda granulate in water, diluting caustic soda or the heat generated during neutralization. The heat exchanger W1 has, in particular, smooth surfaces, as a result of which deposits are largely avoided.

A device W2 with cold water salt is connected upstream of the heat exchanger W1.

The template B4 is also provided with: a fresh water supply line, a pH sensor F4, a supply canister B6 connected via a dosing pump P3 for reagents, eg concentrated hydrochloric acid, a further supply canister B7 connected via a further dosing pump P2, for example for "Make-up" of concentrated sodium hydroxide solution and a B4R agitator driven by a B4RM motor. Both the reactor B1 and the separator B2, the buffer tank B3 and the receiver B4 are connected directly above via a spring-loaded drain valve to an aeration device via lines, preferably made of glass, the aeration device in particular deriving the excess pressure which may arise in one of the vessels. The ventilation device can also include an ozone destroyer B5, in particular with a corresponding supply canister B8 and a metering pump P4. The reactor B1 preferably has a compressed air supply device 270 for the controllable supply of compressed air.

In the device according to the invention for the degradation of elastomers, all of the devices, lines and connections provided are preferably formed from materials which are resistant to organic solvents, lye and oxidizing agents, preferably essentially from stainless steel, glass and / or PTFE.

Both continuous and discontinuous operation are thus possible with the device according to the invention.

According to a further embodiment (not shown) of the present invention, the reactor comprises a receiving device, to which the starting material, for example a car tire, is preferably supplied as a whole. The receiving device can in particular have a holding device (for example one or more hooks or the like) which is guided in or on a rail and which is suitable for conveying or moving the starting material along a predetermined or predeterminable path or path. The receiving device, in particular the rail, is preferably fastened to an upper side of the reactor and allows the starting material to be moved in a hanging manner in the reactor. The reactor further comprises a first feed device for feeding an alkaline substance, which can preferably be sprayed or applied to the starting material under high pressure, in particular by means of one or more nozzles. The starting material is thus the alkaline substance from the first feed device and ozone from one exposed to the second feed device, wherein degraded elastomers, in particular rubber elastomers, can drip down or drain off, where they are taken up by a receiving device, for example a drain. The nozzles are arranged in such a way that the starting material can be wetted with alkaline substance in the hanging, suspended or held state.

The reactor further comprises a delimitation device for its spatial delimitation, which can have one or more brick walls and / or metal walls or the like provided with a protective layer (e.g. made of corrosion-resistant tiles).

The invention will now be further described with reference to the following examples.

EXAMPLE 1

Novapress 200 soft flat sealing material from Frenzelit was broken down by ozonolysis. The formulation of Novapress 200 is as follows:

Share (%) group

Natural rubber 2.83

Kynac 34-140 12.74 elastomer / binder Buna 1572 5.66

Twaron 5.65 Kevlar fiber 5.65

Kieselguhr 16.14 heavy spar 17.69 fillers Kieselguhr 28 MO 19.46 HDK H15 10.32 Sulfur 0.53 Vulkanox MB 0, 1 1 Vulkanox HS 0, 19 zinc oxide Hansa Ultra 1, 69 crosslinking system Vulkacit L 0.29 Vulkacit Thiuram C 0.74 Vulkacit D 0.14

Hostasin red B 30 0, 18 dye

The sealing material (1 kg) was cut into pieces with a diameter of about 5 cm and filled into the filter basket of the reactor. A mixture of 1 N NaOH / toluene at a pressure of 3 × 10 ⁶ Pa (30 bar) at 150 liters / -

Hours sprayed. The temperature was 22 ° C. Tetrabutylammonium iodide was used as the phase transfer catalyst. The ozone mixture consisted of 1% ozone and 99% oxygen. The reaction time was 20 minutes.

After the ozonolysis had ended, the reaction mixture was filtered off through a glass filter crucible, the filter residue was washed with a little hot toluene and then dried at 120 ° C. in a drying cabinet. The filtrate was concentrated and examined by gas chromatography or IR spectrochemical and wet chemistry.

The following were identified in the toluene filtrate by means of GC / MS:

- ethyl acetate, C ₄ H ₈ O ₂

- ethylbenzene, C ₈ H ₁₀

- Cyclopentene-1-ethenyl-3-methylene, C ₈ H ₁₀

- Butoxy-methylbenzene, C ^ H ^ O - phenyl-propanedioxoyl acid, C ₉ H ₈ O ₄

- 3-Cyclohexene-1-carboxaldehyde-1-methyl, C ₈ H ₁₂ O

- iodomethylbenzene, C ₇ H ₇ I

-1, 2-benzenedicarboxylic acid bis (2-ethylhexyl) ester, C ₂₄ H ₃₈ O ₄

The IR spectroscopic characterization of the solid ozonoysis products showed the presence of unchanged polyaramide. Sulfate ions could be detected in the aqueous phase of the reaction mixture. Example 2

Waste rubber from tire manufacture (SBR mixture) was broken down by the ozonolysis according to the invention. The waste rubber (1 kg) was introduced into the filter basket of the reactor. A mixture of 1 M NaOH / toluene at a pressure of 3 × 10 ⁶ Pa (30 bar) at 150 liters / hour was sprayed. The temperature was 22 ° C. Tetrabutylammonium iodide was used as the phase transfer catalyst. The ozone mixture consisted of 4% ozone and 96% oxygen. The reaction time was 35 minutes.

After the ozonolysis had ended, the reaction mixture was filtered off through a glass filter brick, the filter residue was washed with a little hot toluene and then dried at 120 ° C. in a dry state. The filtrate was concentrated and examined by gas chromatography or IR spectrochemical and wet chemistry. The products listed in Table 1 were found. The information in Table 1 relates to the use of 1 t of waste rubber with a 90% turnover.

Table 1

Physico-chemical characterization of the products / residues using the example of breaking down an SBR mixture with metal and tissue for stabilization

1 . Elastomer content (40%)

Fabric analysis method wt%

Acetone IR, GC / MS 12.5 benzaldehyde IR, GC / MS 25.0 ethylbenzene IR, GC / MS 25.0 methyl ethyl ketone IR, GC / MS 12.5 benzene carboxylic acid IR, GC / MS 10.0 higher carboxylic acid IR, GC / MS 3.0 higher aldehydes GC / MS 8.0 higher alcohols GC / MS 4.0

2. Fillers (40%)

Soot Gravimetry 25.0

Sulfur gravimetry 2.0

Grow GC / MS

Plasticizer GC / MS

Anti-aging agent GC / MS 13.0

Vulcanization accelerator GC / MS

Stabilization materials (20%)

Metals wet-chemical 15 fabrics IR 5 Example 3

A natural rubber material (high pressure hoses) was broken down by the ozonolysis according to the invention.

The material composition of these hoses with metal and fabric as stabilizing materials was as follows:

Elastomer content (natural rubber) 45%

Fillers 40%

- carbon black 20%

- sulfur 3%

- waxes

- plasticizer 17%

- anti-aging agents

- vulcanization accelerator

Stabilizing materials 15%

- metal 10%

- fabric 5%

1 kg of the natural rubber material was introduced into the filter basket of the reactor. A mixture of 1N NaOH / 5% isopropanol at a pressure of 3 × 10 ⁶ Pa (30 bar) at 150 liters / hour was sprayed. The temperature was 22 ° C. Tetrabutylammonium iodide was used as the phase transfer catalyst.

The ozone mixture consisted of 5% ozone and 95% oxygen. The reaction time was 20 minutes. An 81% turnover was achieved. After the ozonolysis had ended, the aqueous medium of the reaction mixture was extracted with ether and an extract was examined using GCMS. The following substances were detected by mass spectroscopy:

C ₇ H ₁₂ O ₂ : tetrahydro-3,5-dimethyl-pyran-2-one

C ₇ H _1β O: 2,3-dimethyl-1-pentanol

C ₁₆ H ₂₈ : Hexadecahydro-cyclobutad, 2: 3,4) dicyclooctene

C ₈ H ₁₂ O: 3-methyl-2-norcaranone

C ₁₄ H ₂₆ : undefined hydrocarbon.

Example 4

Physico-chemical characterization of the products / residues using the example of breaking down an NBR / SBR mixture with metal and tissue for stabilization

Reaction conditions:

Temperature: 30 ° C

Pressure: 1 x 10 ⁷ Pa (100 bar)

Concentration of the alkali: 2 N

Catalyst: tetrabutylammonium iodide

Ozone content: 3%

A material turnover of 80% was achieved:

Elastomer content (40%)

Fabric analysis method weight percent

Benzaldehyde JR, GC / MS 10% sec-butylamine JR, GC / MS 8%

Ethylbenzen GC / MS 1 5% higher primary and secondary alcohols JR, GC / MS 20%

higher primary and secondary amines JR, GC / MS 1 5%

higher aldehydes IR, GC / MS 1 5%

Carboxylic acids IR, GC / MS 10%

Methyl ethyl ketone G / MS 7% Fillers (45%)

Soot Gravimetry 20%

Sulfur gravimetry 2.5%

Grow GC / MS

Plasticizer GC / MS> 22.5

Anti-aging agent GC / MS

Vulcanization accelerator GC / MS

Stabilizing materials (15%)

Metals wet chemical 5% fabric JR 10%

Reference list

10 reactor

12 lower part

13 suspension

14 middle section

14 'and 14 "flange

15 seal

16 lids

20 second feed device

22 connection

30 first feed device

32 connection

34 high pressure nozzle

40 ventilation

42 Ventilation connection

50 containers

52 floor

60 drive

62 drive motor

64 gears

66 drive shaft

70 discharge device 72 connection

110 reactor

120 second feed device

122 ozonizer

124 'line

130 first feed device 140 'discharge device

142 'line

144 'filter device 146' valve device

1 50 upper container

1 50 'lower container

1 52 'Feeder for raw material

1 54 'valve device 1 60' conveyor device

220 second feed device

230 first feed device

234 high pressure nozzle

240 aeration 242 'line for filtered reaction solution

250 containers

260 drive

270 discharge device

280 compressed air connection X1 ozonizer

B1 reactor

B2 horizontal separator

B3 buffer tank

B4 template for alkaline substance B4R agitator

B4RM engine

B5 ozone destroyer

P1 high pressure pump

P2 dosing pump P3 dosing pump

P4 dosing pump

F3 pH sensor

F4 pH sensor B6 template canister

B7 make-up

B6 canister W2

W1 heat exchanger

B2D narrowed cathedral

R regenerate

E Elastomers or base material ML center line

Claims

claims

1. Process for the degradation of elastomers, in particular rubber elastomers, by the action of oxygen and solvent, characterized in that the starting material, which may be comminuted, contains elastomer, in particular rubber, a gas mixture of 0.5 to 5 Vol% ozone and 99.5 to 95 Vol% oxygen and at least one alkaline substance in an aqueous and / or organic solvent in the presence of a phase transfer catalyst, the alkaline substance being selected from the group consisting of alkali metal hydroxide, alkaline earth metal hydroxide and ammonium hy - Droxid exists, and wherein the alkaline solution in the presence of ozone through nozzles, at least temporarily under high pressure of 1 x 10 ⁶ to 1 x 10 ⁷ Pa (10 to 100 bar), is applied to the starting material.

2. Process for the degradation of elastomers, in particular rubber

Elastomers, by the action of oxygen and solvent, characterized in that the starting material, which may be comminuted, contains elastomer, in particular rubber, in a gas mixture of 0.5 to 5% by volume of ozone and 99.5 to 95% by volume. % Oxygen and at least one alkaline substance in an aqueous and / or organic solvent, optionally in the presence of a phase transfer catalyst, the alkaline substance being selected from the group consisting of alkali metal hydroxide, alkaline earth metal hydroxide and ammonium hydroxide, and wherein the alkaline solution in the presence of ozone through nozzles, at least temporarily under high

Pressure from 1 x 10 ⁶ to 5 x 10 ⁷ Pa (10 to 500 bar), preferably from 1 x 10 ⁶ to 1 x 10 ⁷ Pa (10 to 100 bar) is applied to the starting material.

3. The method according to claim 1 or 2, characterized in that natural rubber or a polymer containing C ₄ - C ₆ conjugated diolefins, in particular vulcanized rubber or vulcanized polymers, is used as the starting material.

4. The method according to claim 3, characterized in that as a starting material a polymer from the group polybutadiene, polyisoprene, isobutylene-butadiene polymer, isobutylene-isoprene polymer, isobutylene-piperylene polymer or isobutylene-dimethylbutadiene polymer, a polymer from isobutylene and a C ₄ -C ₆ -conjugated diolefin, a brominated or chlorinated polymer from isobutylene and a C ₄ -C ₆ -conjugated diolefin, isobutylene-isoprene-divinylbenzene polymer, an isobutylene-isoprene-2,5-dimethyl-1, 5-hexadiene polymer, a polymer of a C ₄ -C ₆ conjugated diolefin and a vinyl or vinylidene-substituted aromatic hydrocarbon, or a polymer of a C ₄ -C ₆ conjugated diolefin and a C ₃ -C ₅ - uses unsaturated monomer containing nitrile groups.

5. The method according to one or more of claims 1 to 4, characterized in that the alkaline substance is sodium hydroxide or calcium hydroxide, in particular an aqueous solution of 1 to 5 M.

6. The method according to any one of claims 1 to 5, characterized in that a toluene / NaOH mixture is used.

7. The method according to any one of claims 1 to 6, characterized in that one works at temperatures from -60 ° C to 35 ° C, in particular at room temperature.

8. The method according to any one of the preceding claims, characterized gekenn¬ characterized in that the reaction time is from 5 to 240 minutes, in particular from 10 to 30 minutes.

9. The method according to any one of the preceding claims, characterized gekenn¬ characterized in that a phase transfer catalyst from the group of tertiary ammonium salts and / or phosphonium salts, in particular from the group tetrabutylammonium iodide, chloride, bromide, hydroxide or tetrabutylphosphonium chloride is used.

10. The method according to claim 9, characterized in that the ratio of phase transfer catalyst to elastomer material to be worked up is selected in the order of 1: 3 to 1: 8.

1 1. Method according to one of the preceding claims, characterized gekenn¬ characterized in that sealing waste, rubber parts, which are in particular fiber-reinforced, is used as the starting material.

12. reactor (10; 1 10) for performing the method according to one of the

Claims 1 to 1 1, which comprises: a receiving device, in particular a container (50; 150, 150 '; 250), to which an optionally comminuted starting material (E) containing the elastomer or elastomer rubber is fed; a first feed device (30, 34; 130; 230) which feeds an alkaline substance; a second supply device (20; 120; 220) which supplies ozone; wherein the receiving device (50; 150, 150 '; 250), the first feed device (30, 34; 130; 230) and the second feed device (20; 120; 220) are arranged such that the receiving device (50; 150, 150 '; 250) supplied starting material (E) is exposed to ozone, the alkaline substance, optionally the phase transfer catalyst, and at least temporarily the alkaline substance at a high pressure of 1 x 10 ⁶ to 5 x 10 ⁷ Pa (10 to 500 bar), preferably from 1 x 10 ⁶ to 1 x 10 ⁷ Pa (10 to 100 bar) can be applied to the starting material (E).

13. A reactor according to claim 12, wherein the first feed device (30, 34; 234) comprises a nozzle, in particular a flat jet nozzle (34; 234) for feeding the alkaline substance.

14. Reactor according to claim 12 or 13, in which the receiving device, in particular the container (50; 250) is movably or rotatably mounted and is preferably driven by a drive (60; 260).

15. Reactor according to one of claims 12 to 14, in which the container (50; 250) comprises a bottom (52) which has pores, the pores in particular having a diameter of 50 to 300 μm, preferably 70 to 200 μm µm, and particularly preferably have about 100 microns.

16. Reactor according to one of claims 12 to 15, in which a compressed air connection (280) is provided for removing the ozone from the reactor

(B1).

17. Reactor according to one of claims 12 to 16, in which a tempering device is provided for setting a predetermined or predeterminable temperature inside the reactor (10; 1 10; B1), the temperature preferably being between -60 ° C to 35 ° C.

18. Reactor according to one of claims 12 to 17, in which a discharge device (70; 140 '; 270) is provided for discharging the treated starting material (E) as an ozonized regenerate.

19. Reactor according to one of claims 12 to 18, in which a filter device (52; 144 '; B2) filters out the ozonized regenerate (R).

20. The reactor of claim 19, wherein the regenerated from the ozonized

(R) Filtered reaction solution through a line (142 ';242') is fed to the container (150, 150 '; 250).

21. Reactor according to one of claims 12 to 20, in which the supplied ozone is generated in an ozonizer (122; X1), in particular a line (124 ') is provided which conveys the ozone or gas mixture fed through the second feed device to the ozonizer (122).

22. Reactor according to one of claims 12 to 21, in which a mixing device (160 ') supports the mixing of ozone, alkaline substance and starting material, preferably in the receiving device (150, 150'), in particular by moving the starting material.

23. Device for carrying out the method according to one of claims 1 to 11, which has a reactor (B1), in particular according to one of claims 11 to 22, in which is additionally arranged: - a separator (B2), which the regenerate (R) is separated from the reaction solution; a storage container (B4) for an alkaline substance, a first feed device (230) feeding the alkaline substance to the reactor (B1).

24. The device according to claim 23, wherein a line (242 ') is provided to feed the reaction solution separated in the separator (B2) to the reactor (B1).

25. The apparatus of claim 24, wherein the reaction solution in a

Buffer container (B3) can be inserted, which is arranged between the separator (B2) and the reactor (B1), wherein the reaction solution stored in the buffer container (B3) can be fed to the reactor.

26. The device according to claim 24 or 25, in which the separated reaction solution is fed to the reactor (B1) by means of a pump (P1), preferably a high-pressure pump.

27. Device according to one of claims 23 to 26, in which the receiving container (B4) for an alkaline substance has an agitator device (B4R), which is preferably driven by an agitator drive (B4RM).

28. The apparatus of claim 27, wherein a first metering pump (P3) hydrochloric acid from a first supply canister (B6) feeds the storage container (B4).

29. The device according to claim 27 or 28, wherein a metering pump (P3) supplies the alkaline substance from a second supply canister (B6) to the supply container (B4).

30. Device according to one of claims 23 to 29, in which an ozone destroyer (B5) for destroying the exiting from the reactor (B1)

Ozone is provided.

31. The device according to claim 30, in which a third metering pump (P3) supplies chemical substances from a third supply canister (B8) to the ozone destroyer (B5).