DE4106812C2 - Process for recovering the constituents of materials present in the form of a composite of at least two firmly bonded layers of different plastics, and arrangements for carrying out the process - Google Patents

Description

The invention first relates to a method for replenishment win the components of in the form of a composite of at least two solid connected, in particular glued layers of different Plastics and possibly other materials present materials, in which the composite shreds, into its components disassembled and the components from a solid-water mixture separated from each other with the help of hydrocyclones become (preamble of claim 1).

Such a process is known from DE 27 33 279 A1. This pre-release assumes a process for the recovery of paper pulp, Metals and plastic films when recycling Waste of multilayer paper packaging materials, Plastic and metal foils and binders. This multilayer waste material is fed to a disintegrator, where the individual layers are continuous in an aqueous solution separated and shredded or shredded at the same time will. So it becomes the complete material without prior Crushing dissolved in the aqueous solution so far that  the layers separate from each other. Then will still crushed and shredded. The chemical provided there Agents pollute the environment and must therefore be disposed of will. This process is in the grain size achieved limited, d. H. cannot create end products whose Diameter is above this grain size. This disadvantage looks all the heavier than there the size of the hereby resulting particles is very different. This hampers further processing.

DE 28 27 335 A1 describes a process for the recovery of Plastics known, in which the multilayer Plastic object heated and immediately afterwards the heated plastic object by means of shear, impact or Cutting forces should be crushed. For the aforementioned Heating temperatures are in the range of 80-200 ° C called. The crushing is said to be in particles of one size from 0.5-5.0 mm mesh size. Herewith are several Disadvantages connected. A corresponding one is for the heating Equipment and energy expenditure required. Another Apparatus-like effort results from the fact that immediately after the heating has to be comminuted. The aforementioned Melting temperatures are about 20-30% higher than the melting points of the plastics to be processed. Herewith but if they become doughy or viscous after heating, whereby the plastic particles stick to each other. However, they are not in this state by means of impact crushers separable. But even if a crushing should be feasible, the particles stick due to the Warming together. The bottom line is neither usable comminution of the composites into individual particles, another so-called disintegration of the individual particles in their individual layer components can be reached successfully. The term "disintegration" is a process understood, in the small, but still from individual composite layers  existing particles are processed so that separate the layers of these particles from each other. The in Preamble of claim 1 mentioned separation of the components with the help of hydrocyclones is the aforementioned reference not to be removed. So glued together Plastic particles would not be with hydrocyclones or Process hydrocyclone assemblies.

Compared to the aforementioned prior art, the present invention with the field of recovery and sorting the components from composites Layers, the layers each of different Plastic and a structural unit in the form of the above Bonded together or otherwise firmly together are connected. Such a network can, however, additionally one or more of these plastic layers Layers of another material, e.g. B. from a metal or an organic material, such as a wood fiber, exhibit. The gluing mentioned above also includes melting of polyurethane or the like. The gluing can be done without using a binder. The one mentioned firm bond can also be mechanical. Such composites In practice, several layers come as Dashboards or dashboards of motor vehicles because these are usually combinations nowadays of layers of different plastics and possibly other materials, such as a supporting metal layer and / or a layer of wood fiber. For example the visible side of a dashboard made of a plastic film be formed, behind which there is a foam layer as padding located both with the plastic film as also with a rear, usually thicker and more rigid Support layer made of a correspondingly hard plastic or Metal is glued. Already in the production of such Dashboards generate waste in the form of the stamping residues. If  the motor vehicle in question is to be scrapped the entire dashboard as garbage. Since after the previous one State of the art such panels not or only poorly separated into its components and then into the individual Material components could be sorted remained in the practice of removing the punching residues and ver scrapping dashboards only the landfill as hazardous waste. This is extremely complex and for reasons of environmental protection to avoid. As already mentioned, recovery is and sorting the plastic parts or layers and against if necessary, layers of other Armaturenta materials motor vehicles are not the only, albeit one preferred application of the invention. Other areas of application te are bumpers on motor vehicles, but also correspond appropriate networks from such layers in other industries or other objects.

The task outlined above for Connected such assembled, especially glued together Plastic layers and possibly layers of others Materials the recovery and sorting of each Plastics and possibly other materials inexpensively and to achieve properly, with the invention starting from the preamble of claim 1 cited at the outset procedurally solved in that the size reduction mechanically dry without pretreating the composite material Single composite pieces made with a size of 1-2 cm² is, and that the composite items subsequent to the Shredding or in one operation with the shredding by beating, shearing and cutting action in their components are disassembled (so-called disintegration). Disintegration is also possible if the layers are glued together. That through disintegration Small components obtained consist only of a plastic or the component of a plastic layer. From the above it follows that the separation of a Composite of several plastic layers in particles only one specific type of plastic  is achieved. In cases where in addition to Plastic layers also layers of other material, how metal or wood fiber is present is for their Co-crushing taken care of, each one layer or Form layers of the composite items and through the Disintegration from each other and from the other plastic layers separated and then also separable. So it becomes a mixture of the various components Layers formed that then into the individual art fabric types, if applicable also particles from other materials is separated and sorted. This will eliminate the achieved the garbage problem described above. About that In addition, the sorted particles of the different Types of plastic and if necessary other types of material in one such purity that they are again for the original use can be used. It So there is complete recycling. The disadvantages of Wet processing according to DE 27 33 279 A1 and heating after DE 28 27 335 A1 are avoided. A warming of those to be separated Plastic layers or parts are not provided still necessary. So there is a purely mechanical, dry Separation. The particle size of 1-2 cm² is essential Significance for separation by means of hydrocyclones or Hydrocyclone assemblies. With each shredding a Waste, the size of the waste particles being significantly below the size of the individual pieces to be separated later resulting components lies. Would that Single composite pieces or the resulting components only the maximum size of 0.25 cm² according to the DE 28 27 335 A1, the share of waste would then be which can no longer be processed using hydrocyclones large. In contrast, the provided with the invention Size of the composite items or resulting from them Ingredients of 1-2 cm² the resulting, by means of hydrocyclones Proportional waste no longer to be processed proportionately low. Such a portion is used in crushing sifted out. The features of claim 1 are thus functional and synergistically to the result, one  effective, sharp and without much material loss Separation of the individual layers of the composite individual pieces to reach from each other.

If components with a greater specific weight than 1 through the hydrocyclones or hydrocyclone arrangements are separate, are the procedural features of the claim 2 provided.

There are cases in which a composite metal parts or -Layers that with the intended arrangement for the crushing of a composite of plastic layers cannot be crushed. In this case, according to Claim 3 an addition to the method by a previous one Separation and separation of such metal parts or layers intended.

The invention is also intended Arrangements are created that are more advantageous and practical way of performing the aforementioned Procedural measures serve.

For this purpose, an arrangement according to the characteristics of the Claim 4 provided. This will create the desired crushing effect without the help of warming (which in the would be disadvantageous) and without the use of an aqueous Solution reached. The preferred embodiment of such Arrangement is the subject of claim 5. Such drum ripper are for shredding wood waste of all kinds, Cardboard and paper known with the aim of having the shredded Share e.g. B. by briquetting, a loading of To enable firing systems. The use of such drum rippers for carrying out the method according to the invention is new. The result is perfect. Mentioned be that glued or fused plastic particles together according to DE-OS 28 27 335 from one  Drum rippers cannot be processed in the sense of the invention could. Since when using a drum ripper according to claim 5 dust-like fine particles, e.g. B. in the presence of a Wood pulp layer can form the free fiber fraction a wind sifter is recommended according to claim 7.

The features of claim 8 create a particularly intensive Separation. In particular, are recovered plastic particles achievable with a very high degree of purity, so that these are new again, e.g. B. used for the same purpose can be.

The features of claim 9 enable the defibration the wood fiber material the further cleaning of residual plastic particles by screening and reusing the obtained fiber material.

The features of Anspurches 11 give the advantage that a and the same system optionally for processing and separation of composite layers of different types settlement can be used. It just has to go through Open or close the existing connection lines the respectively necessary connections made or in the case not required or even harmful Connection lines are interrupted. By optional Can close / open the relevant connecting lines from different suspensions with a mixture of Particles of different materials each in a particle certain type of material, especially plastic, separated and be sorted.

Because such systems cost a considerable amount Effort and also the availability requesting a suitable place comes this advantage a very important one by using relative low cost a problem that has not yet been solved optimally and is remedied in an environmentally friendly manner.

For example, below listed composite layers in the specified individual Components or plastics are separated:

• a) PP / other,
• b) PVC / PU / SMA,
• c) PVC / PU / wood fiber,
• d) PVC / wood fiber
• e) one or more of the aforementioned composition plus a metal layer, the Metal layer the respective plastic layer can replace.

For example, the above specification a) PP / other be: 89% PP, 10% metal and 1% waste, like other plastics.

The invention will below  based on the drawings through several design options explained. The essentially schematic The drawings show:

Fig. 1 is a flow diagram of a system with which a number of different composites of plastic layers, optionally layers of other materials, can be separated and sorted in the sense of the invention, a composite of PVC / PU / SMA to be crushed and sorted and the components and connecting lines required for this are specially marked,

Fig. 2 shows the installation according to Fig. 1, but with marking or highlighting the components and connection lines for the separation of a further, other bodies combination of layers, namely, PVC / wood pulp or PVC / PU / wood pulp,

Fig. 3 shows the system of FIG. 1 with labeling, or highlighting the components and connecting lines for the separation of a plastic (PP) from other components, with the possibility of an upstream metal reduction and separation is also shown.

FIGS. 4 to 6 are schematic illustrations of examples to be processed, one or more plastic layer (s) containing composites.

On the basis of the flow chart of FIG. 1, the separation and purification is a composite of plastic layers is Darge consisting of PVC, polyurethane (PU) and Styrolmalinanhydrid (SMA) (see also Fig. 4). The connecting lines provided with an arrow are flowed through by one of the materials or components or a suspension, but the connecting lines not provided with the arrow are not. If necessary, the latter connecting lines can be shut off by not shown stopcocks or similar closing means for this operating case. The composite composed of individual layers is fed in at 1 and fed to a drum shredder 2 , which divides the plastic composite into composite individual pieces and these into components of the individual types of plastic, here into PVC particles, PU particles and SMA particles. First, the composite in the composite items of z. B. 1-2 cm ² surface punched or crushed, the separation of the United bundle pieces in the components of the layers is effected by shear forces. Below this shredding space, a sieve can be provided which only allows particles up to a certain size to pass through. This mixture of particles from the above-mentioned components is fed via line 3 to an air classifier 4 , which separates the fine abrasion via 5 and deposits it in a container 6 . The underflow 7 of the air classifier 4 is fed via a line 8 to one or more intermediate storage stations 9 in order to reach a first stirred tank 12 via the line 10 and the line 11 . In the stirred tank 12 , the particle mixture is adjusted by means of water supply (not shown) to a solid water suspension in such a way that the downstream hydrocyclone can be operated with the optimal operating parameters for the separation. The aforementioned solid water suspension passes through line 13 to a first hydrocyclone stage 14 . The overflow 15 of the hydrocyclone stage 14 contains PU foam, which is fed via a line 16 to a second stirred tank 17 and from there via line 18 to a second hydrocyclone stage 19 , which represents a second post-cleaning stage. Small amounts of PVC and SMA contained in the overflow 15 of the first hydrocyclone stage are separated in the second hydrocyclone stage 19 and go back via the underflow 20 and the line 21 into the first Rührbe container 12 . The heavy fraction of the first Hydrozy clone stage 14 , which consists of PVC and SMA, goes as underflow 22 via line 23 to a sieve 24 and from there via line 25 to a further, third stirred tank 26 . From this third stirred tank, the suspension is fed via line 27 to a third hydrocyclone stage 28 .

The overflow 29 of the second hydrocyclone stage 19 goes via the lines 30 , 31 and optionally an intermediate sieve 32 to a sieve 33 and from there via a sieve belt press 34 into a collecting container 35 . This overflow contains PU, which is obtained in the form of sorted PU particles in the collecting container 35 .

The hydrocyclone stage 28 already mentioned is operated with a heavy slurry. Your underflow 36 contains the SMA particles and is fed via a line 37 to a dewatering screen 38 , from there via line 39 , a centrifuge 40 , a line 41 , a thermal dewater (dryer) 42 and an outlet line 43 to one Collecting container 44 to arrive. This collecting container 44 thus contains the sorted SMA particles.

The overflow 45 of the third hydrocyclone stage 28 goes via line 46 , a sieve arrangement 47 and a line 48 to a fourth stirred tank 49 . The suspension formed here is then fed via line 50 to a fourth hydrocyclone stage 51 . The underflow 52 of this fourth hydrocyclone stage is returned via sieves 53 and a line 54 to the third stirred tank 26 in order to be fed from there to the third hydrocyclone stage 28 for a further re-separation. The overflow 55 of the fourth hydrocyclone stage is fed via a line 56 , sieves 57 , a line 58 , a Zen trifuge 59 , a line 60 and a thermal drainer 61 to an outlet 62 . From here, the PVC thus separated arrives in a collecting container 63 , which thus contains the sorted PVC particles.

If one does not place very high demands on the purity of the separated and sorted particles, one could do without the second and the fourth hydrocyclone stage and the associated stirred tanks. In this case, the PU separated from the overflow of the first hydrocyclone stage 14 would be dried and collected immediately. Furthermore, the PVC separated from the overflow of the third hydrocyclone stage 28 would then also be immediately dried and collected. However, if a very high level of purity is important, and this is particularly sought and achieved with the present invention, the explained second and fourth hydrocyclone stages are to be used, including the components upstream and downstream of these. This also applies to the other exemplary embodiments.

In Fig. 1, a strainer 80 is also provided for intermediate cleaning of the dirty th, through the line 79 supplied circuit water. During this intermediate cleaning, the dirt particles are fed to a container 81 . The cleaned water flows into a collecting tank 82 and from there by means of a pump 83 and a line 84 to the location of the circuit at which purified circuit water is required in each case. The above-mentioned turbidity is produced in that a corresponding mineral at 85 dry and finely ground is fed to another stirred tank 96 . There it is mixed with water to form a corresponding heavy slurry suspension and fed via line 86 or 87 to the respective hydrocyclone system to be operated with heavy slurry. The recovery of the heavy cloudy is indicated by paragraph 88 .

Fig. 2 shows the same system as Fig. 1. As far as the same parts and lines are used, they are designated with the same numbers as in Fig. 1. Also applies to Fig. 2, only that the lines employed are provided with an arrow. The active in Fig. 2, namely numbered or provided with an arrow parts and lines are used for separation of PVC / wood fiber (see also Fig. 5). The task and crushing and air separation according to numbers 1 to 4 is carried out as in the example in FIG. 1. The air classifier 4 is preceded by a fan 88 which loosens and separates any Gewöllbil formation of the wood fiber material in the drum breaker 2 , so that the wood fiber materials in this form the air classifier 4 are supplied. The overflow of the Windsich ters 4 contains wood fiber material as a light fraction in this example, namely the free fiber fraction. According to an exemplary embodiment, the air speed in the air classifier is approximately 5.3 m / s, the air throughput is approximately 22.3 m ³ / h. The underflow 7 contains the heavier or coarser wood pulp and the PVC and is fed from the intermediate storage station 9 via a line 10 and a line 111 to a washing and wetting screw 64 and mixed with water there. This is followed by a further comminution to final grain size in a wet mill 65 (in which an optimal sorting is achieved), in order to be fed from there via a dewatering screw 66 and line 67 to the first stirring container 12 . Contamination can be deposited on a sieve 68 in a container 69 .

A suspension forms in the stirred tank 12 , in which the wood fiber particles and the PVC particles are already loosened up and worked up well, so that they can then be separated very well in the first hydrocyclone stage 14 .

The underflow 22 of the first hydrocyclone stage 14 is fed here via a line 70 to a stirred tank 71 . The mixture forming the underflow 22 from PVC particles and larger particles of wood pulp is then fed to a pulper (substance Dissolver) 72nd This pulper dissolves the wood fiber particles even further and frayed them. This then goes together with the PVC particles to another Rührbe container 73rd In this case, up to the stirred tank 71 and from the stirred tank 73 is operated continuously, while the operation from the stirred tank 71 via the pulper 72 to the entrance of the stirred tank 73 is discontinuous and the pulverizer 72 can thus be operated discontinuously. From the above, it also follows - as also shown in FIGS. 1 and 2 graphically to express - that the chain of components 71 , 72 and 73 only with a composition of the layers to be processed according to the embodiment example of FIG. 2 for resolution and separation the wood fiber is to be operated, while the aforementioned chain of components 71 to 73 is not required in a composition of the composite according to the embodiment of FIG. 1. This also illustrates the versatile use of such a system. The output of the stirring container 73 reaches a slot sorter 32 via a line. The waste from this sorter contains PVC and undissolved wood fiber. It is fed to a further stirred tank 74 in order, from there, after being mixed with water, to reach the stirred tank 26 via line 75 , which in FIG. 1 forms the third stirred tank. Via the line 27 this suspension of the hydrocyclone stage 28 is then supplied, which forms the third hydrocyclone stage in the application of FIG. 1. Its underflow 36 is fed via line 37 , sieve 38 , line 39 , centrifuge 40 , line 41 , dryer 42 and line 43 to the collecting container 44 . Only in this application of FIG. 2 are the separated PVC particles collected there. The lower reaches of the slot sorter 32 contains free wood fiber materials, which are fed to a sieve 33 and thrown by this onto the belt press 34 and, after pressing out the water components, are placed at 35 abge.

If a layered composite consisting of PVC / PU / wood fiber material is processed with this system, in addition to the measures described above for FIG. 2, PU must also be separated and deposited. This is indicated in Fig. 2 to distinguish the processing of a layer composite of PVC and wood fiber by dashed arrows. With the overflow of the first hydrocyclone 14 , the PU is fed to the pipe container 17 via the line 16 in order to reach the hydrocyclone 19 via the line 18 . With the overflow of this hydrocyclone, it flows via line 30 to a sieve 89 and a centrifuge 59 and as its discharge via line 60 to a dryer (thermal drainage) 61 , in order to be thrown off there in container 63 as PU. The overflow of the centrifuge 59 consists only of water and goes back into the circuit (see components according to paragraphs 79 to 84 ). It should be mentioned that the overflow of the hydrocyclone 28 leads via the line 45 into the stirred tank 12 , this overflow containing water and undissolved wood fiber materials.

Fig. 3 also shows the system of FIGS. 1 and 2, namely for the separation of PP and other components. "Other ingredients" are all plastics and impurities with a specific weight of ρ <1.0 kg / dm ³ , z. B. polyamide (PA), polycarbonate (PC), polyvinyl chloride (PVC), iron (Fe), aluminum (Al), polyamide glass fiber reinforced. For these other parts, it is true that a two-stage sorting is necessary to achieve the highest purity of the end result, as has already been explained in detail with reference to FIGS. 1 and 2 for the plastics SMA and PVC. The course of the liquids, suspensions, etc., as in FIGS. 1 and 2, is shown with arrows. Furthermore, the same reference numerals have been used with regard to the components, such as hydrocyclones, etc. To avoid repetition, reference may therefore be made to the explanations relating to FIGS. 1 and 2. The PP is thrown into the container 63 and the "other ingredients" on the centrifuge 40 or in the case of thermal dewatering into a container 44 .

It can be seen that one and the same system, as shown overall in FIGS. 1 to 3, for the separation of the individual plastic components of a layer-like composite of several different plastics, and optionally one or more layers of other materials, can be used without having to change the structure of the system itself. In the context, Fig. 4 shows a composite of layers 90 (PVC), 91 (PU) and 92 (SMA), which are glued together at their contact surfaces 76 and separated from one another in the manner explained in relation to FIG be sorted. In the case of a dashboard, PVC is the plastic film on the visible side, PU the upholstery layer and SMA the hard, load-bearing layer. Fig. 5 shows the combination of PVC (90) and wood fiber materials (93), which are bonded together along the connecting surface 77. Here, too, PVC is the visible side in the form of a film, while the load-bearing layer consists of wood fiber. While the desired, very high level of purity for plastics, such as PVC, PU and SMA, which can be recycled, is achieved through the two-stage process explained, this is done in the case of wood fiber materials through the chain of components 71 to 73 , and especially through the Dissolver 72 .

Due to the versatility of the system, composite systems are also possible from other plastic combinations, if necessary together with layers of other materials, crushed, ge separated and sorted.

Fig. 6 shows a supporting metal layer 94 and these (90) by gluing their surface 78 with polyurethane (91) by gluing their surface 76 with a corresponding PVC composite of layers. If the drum ripper 2 can shred this metal layer ( 94 ), this composite is processed in exactly the same way as is shown in FIG. 1 using PVC / PU / SMA. Here, too, it goes without saying that, with a correspondingly high specific weight of the particles, the hydrocyclones concerned work with a suspension of heavy turbidity and that the metal particles can also be subjected to a two-stage sorting.

If necessary, however, the drum breaker 2 can be connected upstream of a device suitable for crushing thicker or larger metal parts or layers, such as a shredder, wherein devices are provided between the shredder and drum breaker for detecting the metal particles and removing them from the batch. A shredder with associated metal detector and separator is indicated schematically with the number 95 in FIGS. 1 to 3. It is also within the scope of the invention to limit the aforementioned metal detector and the devices for separation to those metal parts that have a certain size, e.g. B. exceed a diameter of 30 mm, while the smaller metal particles are then processed by the system as it has already been described in FIGS. 1 to 3 in detail to the plastic layers and the particles formed therefrom. In this case, the shredder performs a preliminary shredding.

The invention is not based on the use of the illustrated Components limited. Instead, we can do the same kende other components may be provided.

Claims (11)

1. A method for recovering the components of substances present in the form of a composite of at least two firmly bonded, in particular bonded layers of different plastics and possibly other materials, in which the composite is comminuted, broken down into its components and the components from a solid-water mixture Hydrocyclones are separated from one another, characterized in that the comminution is carried out mechanically without pretreatment of the composite material in composite individual pieces with a size of 1 to 2 cm² and that the composite individual items are then crushed or in one operation with comminution by impacting, shearing and cutting action can be broken down into its components. 2. The method according to claim 1, characterized in that the components for their separation with a sludge to be mixed to form a heavy slurry suspension.   3. The method according to claim 1 or 2, characterized in that the crushing of the composite is a crushing and separation of an existing metal layer is connected upstream. 4. Arrangement for performing the method according to one of the Claims 1 to 3 with a shredding device and several hydrocyclones, characterized in that a mechanical shredding device with beating, shearing and cutting tools is. 5. Arrangement according to claim 4, characterized in that a drum shredder ( 2 ) is provided as the shredding device. 6. Arrangement according to claim 5, characterized in that below the drum breaker ( 2 ) a screen is attached, which only allows components up to a certain size. 7. Arrangement according to claim 5 or 6, characterized in that the drum ripper ( 2 ) is followed by an air classifier ( 4 ). 8. Arrangement according to one of claims 4 to 7, characterized characterized that four connected in series Separation stages, in particular hydrocyclone stages, are provided are. 9. Arrangement according to claim 7 or 8, characterized in that in the presence of a layer of wood fiber the lower outlet of the air classifier via a washing and wetting screw ( 64 ) and a wet mill ( 65 ) is connected to the first stirred tank ( 12 ). 10. The arrangement according to claim 9, characterized in that a substance dissolver ( 72 ) is provided after the first hydrocyclone stage ( 14 ). 11. Arrangement according to one of claims 4 to 10, characterized characterized in that the connecting lines between the individual hydrocyclones optionally by shut-off devices to be closed or opened.