Process for recycling automotive elastomeric trim waste

Technical Field

[0001] A process and device for recycling waste material from automotive trim parts, wherein the automotive trim parts comprise at least a bilayer consisting of a thermoplastic elastomeric resin based surface layer with less than 5% by weight fillers content, and a thermoplastic elastomeric polyolefin based backing layer with a filler content above 55% by weight.

Background Art

[0002] Flooring systems used in driver compartments of trucks as well as load floor areas of SLIVs and small vans were traditionally made of polyvinylchloride. Later this was replaced by soft or hardwearing surfaces based on polyolefin based materials. These aesthetic surface layers are predominantly thermoplastic elastomeric polyolefin based layers, optionally embossed with a grained or patterned surface to increase durability and visual appearance, as well as to increase the grip of the floor.

[0003] The thermoplastic elastomeric resin based surface layer may be up to 500 gr/m ² . It may comprise of predominantly polyolefin resins, or may consist of polyolefin resins, or may further comprise a very low level of filler.

[0004] Typically, in order to enable a good coverage of the intended floor area, a heavier backing layer may be laminated onto the non-visible side of the surface layer. This backing layer is shaped together with the surface layer, to cover the area dedicated to the floor covering part. This might include curved areas as well as changes in direction of the flat areas, to encompass any channels or wall structures that need to be covered seamlessly as well. Generally, the backing layer is also a thermoplastic elastomeric polyolefin resin based (TPO) layer but with properties different from those of the surface layer. In particular, it contains a high load of inert filler, like CaCOs. The filler content might be between 55 and 98%. In addition, the weight of the backing layer used to keep the aesthetic layer on the floor may be up to 4kg/m ³ . At least 1 ,5kg/m ³ is needed. [0005] Although both layers are based on thermoplastic elastomeric material, preferably thermoplastic elastomeric polyolefin (TPO) based material, the above-mentioned differences between the surface layer and the backing layer make recycling difficult. In fact, a reclaimed mix of the material of the surface layer and that of the backing layer may not be used again either in the production of the backing layer or in the production of the surface layer: in the former case the resulting backing layer would have reduced mechanical stiffness, while in the latter case the surface layer would be of reduced aesthetic value (due to the presence of the fillers) and have a reduced durability. In both cases, this would result in layers that are not suitable for the production of for instance truck cabin floor covering trim parts.

[0006] Hammer mills are known as devices to be used in recycling processes for various kind of materials for a sole size reduction process step. All materials fed into the milling chamber is pulverized and passes through the grate or perforated plate at the lower area of the milling chamber.

[0007] Hence, it is the object of the current invention to provide a process for recycling waste material from automotive trim parts comprising at least a bilayer consisting of a thermoplastic elastomeric resin based surface layer with a low content of fillers and a thermoplastic elastomeric polyolefin (TPO) based backing layer with a high content of fillers laminated together, which is able to separate the materials of the layers again to enable separate recycling.

Summary of invention

[0008] The objective is achieved by a process for recycling waste material coming from automotive trim parts with at least a bilayer consisting of a thermoplastic elastomeric resin based surface layer with less than 5% filler content, and a thermoplastic elastomeric polyolefin (TPO) based backing layer with a filler content above 55%, according to the main claim and the claims depending on it, as well as by the device according to claim 15 and the claims depending on it. [0009] In particular, by a process comprising the steps of:

- step 1 : provide a feedstock F consisting of automotive trim part waste comprising at least a bilayer consisting of a thermoplastic elastomeric resin based surface layer with less than 5% by weight fillers content, and a thermoplastic elastomeric polyolefin based backing layer with a fillers content above 55% by weight;

- step 2: form feedstock F’ by reducing the feedstock F provided at step 1 into chips all having approximately the same size of between 5 and 60 mm, measured at the largest cross-section parallel to the plane of the layers, preferably between 10 and 30mm, more preferably between 10 and 15 mm;

- step 3 feed feedstock F’ into a rotating hammer mill, whereby hammers rotate along at least one perforated screen set at a distance from the tip of the hammers over the full rotation of the hammers, and whereby the action of the hammers is such that the backing layer is broken and separated from the surface layer and pulverized into particles that are and filtered through a perforated screen or grid thus forming material fraction A, while the surface layer is not substantially reduced in size and remains as flakes in the milling chamber and forms material fraction B, and

- Step 4 removing material fraction B from the milling chamber.

[0010]

[0011] Surprisingly, the impact stress on the chips comprising the bilayer of the thermoplastic elastomeric resin based surface layer with less than 5% of filler content and the TPO backing layer with at least 55% of filler content induced by blows of the hammers as well as any crash against the wall of the milling chamber introduces a frictional stress in between and within the layers and causes the polyolefin material of the backing layer to break, separate from the surface layer and pulverise, while the thermoplastic elastomeric polyolefin resin material of the surface layer remains substantially intact, enabling a high yield separation of both layers.

[0012] It is now possible to recycle the high value surface material back into surface layer production, while the filtered out fraction of the backing layer material may be used as filler again in the backing layer production. As the surface layer remains substantially intact, cross contamination of the backing layer material fraction with the surface layer material fraction is reduced to such an extent that both fractions are suitable for use in the recycling processes of the respective layers, thus solving the problems of the prior-art.

[0013]

[0014] The waste material for the feedstock F may comprise cut-offs, cut outs, faulty parts, or end-of-roll material as well as end of life trim parts from the production of automotive trim parts comprising a bilayer consisting of a thermoplastic elastomeric resin based surface layer with less than 5% by weight of filler content, and a thermoplastic elastomeric polyolefin based backing layer with a filler content above 55% by weight. This bilayer may be used and produced as such or it might be combined with easily separable layers like for instance a foam layer laminated onto it.

[0015] In principle clean waste, produced before the trim parts are used in the car may be used without treatment, while end of life material may be used after preferably a surface wash to reduce any traces of dirt or grease that may interfere with the reuse of the final fractions.

[0016]

[0017] Preferably, the waste material coming from the automotive trim part production or from end of life parts may be cut into smaller pieces as in order to fit the inlet of the machines used in the process according to the invention. Optionally additional layers like foam layers, preferably polyurethane foam layers, may be separated before for instance by a splitting or shaving process. Small amounts of additional layers may be still be present in the waste feedstock F used for the recycling process according to the invention, without reducing the effectiveness of the process itself.

[0018] Step 2, the shredding, may be done directly before the next step of the process according to the invention or it may be separated in time and/or space. In particular, it may be advantageous to carry out this shredding already at the production site of the automotive trim part, to minimize the space needed for storage and transport. [0019] This shredding or cutting of the waste feedstock into small chips or shreds may be done with a conventional grinder, shredder or cutting machine known in the art. In this step the waste feedstock is only reduced in size, preferably without substantially producing dust.

[0020] The bilayer material shredded into substantially equal size chips or shreds forms feedstock F’ for the third process step.

[0021]

[0022] The feedstock F in step 1 may comprise of waste material from automotive trim parts that further comprise a foam layer attached to the backing layer. Such waste material including the foam layer may be subjected to a further separation step, whereby the shredded material resulting from step 2 is passed through a cyclone separator to eliminate the foam fraction before step 3.

[0023] In an alternative embodiment different waste streams coming from different trim part production having at least one layer, preferably the backing layer, in common or compatible may be combined to form feedstock F.

[0024]

[0025] In an optional step, fraction A and fraction B obtained from step 3 and 4 may be subjected to melt filtration, to eliminate any residual debris, and pelletized. The thus obtained pellets may be used in subsequent extrusion or injection moulding processes for making other parts or layers for automotive or non-automotive applications.

[0026] The process may further comprise a step of pre-separating the bilayer from additional layers, preferably before step 1. This is possible for instance for fluffy or surface-bonded layers which are not strongly bonded or intertwined with the bilayer. These layers may be peeled off or separated using for example a blade knife.

[0027]

[0028] The thermoplastic elastomeric resin material of the surface layer and/ or the backing layer may comprise a thermoplastic elastomeric polyolefin based material, preferably a thermoplastic elastomeric polypropylene, or a thermoplastic elastomeric polyester-based material. [0029] Preferably the surface layer is a multilayer, whereby the dominant layer or layers are formed by the thermoplastic elastomeric resin material and at least one of the outer layers is laminated to the backing layer. The additional layers may be coloured or patterned layers combined with a sacrificial top layer. These layers are normally formed of a basic thermoplastic elastomeric resin material adjusted with additives, like colouring or hardener or softener to obtain a multilayer surface with different functional requirements.

[0030]

[0031] The waste material may comprise a bilayer consisting of the thermoplastic elastomeric polyolefin (TPO) aesthetic surface layer and a thermoplastic elastomeric polyolefin backing layer.

[0032] More preferably the bilayer consists of a thermoplastic elastomeric polyolefin (TPO) surface layer without fillers and a thermoplastic elastomeric polyolefin (TPO) layer with a filler content of at least 55% by weight and not more than 95% by weight.

[0033] The thermoplastic elastomeric surface layer or backing layer may comprise inert fillers, preferably calcium carbonate.

[0034] The recycled fraction A or B from the process according to the invention may be fed combined with virgin thermoplastic elastomeric material compatible with the fraction in order to produce a thermoplastic elastomeric layer, for example by means of an extrusion process. The thus produced layer may be used in automotive trim parts. A reclaimed fraction at most 30% by weight of the newly produced layer may be used depending on the fraction and the properties of the newly defined layer.

Description of embodiments

[0035] In a realization of the process according to the invention, the automotive trim waste pieces are picked up at the inlet of the hammer mill and, thanks to the action of the hammers, smashed against impact plates or breaker blocks in a first area of the hammer mill, where the shredded waste is rebounded back into the area of the circling hammer heads. Preferably blunt hammer blades are used to increase the impact force. The thus hit waste chips may be picked up and smashed multiple times against the walls of the hammer mill or against the grate or perforated plate, where shear forces between them and the hammers reduce the trim waste pieces by breaking off the high-filled material of the backing layer from the low-filled material of the surface layer and grinding it until the particles pass the grate or perforated plate and leave the milling chamber. The remainder of the feedstock pieces is mainly the surface material that may be removed from the milling chamber via a separate outlet area. Alternatively the end of the grate or sieve area has a larger opening size and the remainder of the chamber content may be purged through this last zone.

[0036]

[0037] Surprisingly, separating the low-filled thermoplastic elastomeric resin material from the high-filled TPO material may be done in a hammer mill device according to the invention adapted to release the remaining fraction from the milling chamber just in time before this is further degraded in powder or particles. Hence, only the high-filled TPO material may be ground off the trim waste pieces while the low-filled thermoplastic elastomeric resin material flakes remain substantially intact until being released from the milling chamber via a separate outlet. Such outlet may be either a perforated grate or grid area with a size of perforation large enough to release these material pieces or an outlet channel into which the remaining low-filled TPO material pieces are catapulted by the action of the hammer heads and/or by the airstream produced inside the milling chamber of by a part of the milling chamber wall being able to open and close.

[0038] The dwelling time may be optimised to ensure that the surface material is not broken up and degraded into powder or particles. The surface material may be removed from the main milling chamber intermittently, in manual or automatic mode. Alternatively the last grate size is such that all shreds will fall through. This might be an area that is only opened up temporarily to enable removal but also to guarantee that the material is in the milling chamber long enough. The filling and the emptying of the milling chamber may be a batch type interval process. [0039] In case the trim part comprises additional layers like a foam layer against the backing layer, these layers may be pre-separated or the trim part waste including the foam layer may be reduced in size during shredding process (i.e. step 2 of the process according to the invention). In this case an optional step may be introduced, whereby the shredded material is separated in a cyclone to eliminate the foam fraction before step 3 of the process according to the invention.

[0040] The tip speed of the hammer blades as well as the distance from the hammer tip to the impact plates and grates may be optimised to ensure enough breaking impact on the particles to break of the highly filled material in a pulverising way.

[0041] The hammers in the hammer mill are preferably blade shaped with a blunt edge. Multiple blades may be arranged on one rotating shaft such that the tips of the hammer heads are passing along the curved hammer mill wall at an equal distance or at a distance that is reduced in the direction of rotation such that smaller particles cannot build up a layer between the perforated screen and the heads, reducing the efficacy of the hammer mill. Outer blades situated at the start or end of the shaft, having one side of the blade directly opposite to a side wall of the milling chamber may be adapted in shape to prevent forming of a material cake on these wall sides.

[0042]

[0043] During the rotation of the hammers the waste feedstock is picked up at the inlet and transported around. The surface fraction will remain within the milling chamber as flakes until manual removal, or may be transported to an outlet orientated after the area with the perforated screens, preferably just before the inlet area of the feedstock, when related to the turning direction of the hammers. The removal may be aided with guiding plates and may be benefitting from the centrifugal force on the surface material flakes obtained by the action of the hammers. The surface flakes may be removed continuously or intermittently via the fiber outlet. The removal of the surface material from the milling chamber containing the hammers may be aided by an airstream. [0044] After the hammer mill process step at least two main material fractions are obtained: fraction B in the form of thin flakes essentially consisting of the thermoplastic elastomeric resin based material of the surface layer and fraction A in the form of a powder or granulate essentially consisting of the thermoplastic elastomeric material polyolefin based material of the backing layer and the fillers. It may be that the elastomeric material of the backing layer and its fillers are at least partly separated in material fraction A. Hence the filler may be included fraction A in the form of separate particles.

[0045]

[0046] Surprisingly, the difference in filler content between the two thermoplastic elastomeric resin based layers enables an easy separation of these layers. In fact, the high fillers content increases the brittleness or crumbling tendency of the backing layer, while the lack of fillers increases the elastomeric behaviour of the surface layer.

[0047]

[0048] The invention further covers a device for step 3 and 4 of the process according to the invention, being step 3 feeding feedstock F’ into a rotating hammer mill, whereby hammer blades are rotating along at least one perforated screen set at a distance from the tip of the hammer blades over the full rotation of the hammer, and whereby the action of the hammer blades is such that the backing layer is broken off and separated from the surface layer and pulverized into particles that are filtered through a perforated screen or grid thus forming a first material fraction A, while the surface layer is not substantially reduced in size and remains as flakes in the milling chamber and forms a second material fraction B, and being step 4 removing fraction B from the milling chamber.

[0049]

[0050] Such a device for recycling waste material from automotive trims parts comprising a bilayer consisting of a thermoplastic elastomeric resin based surface layer with less than 5% filler content, and a thermoplastic elastomeric polyolefin based backing layer with a filler content above 55% comprises in combination

- a milling chamber delimited by an essentially cylindrical wall and two side walls, and

- rotating hammers spatially organised on a rotating axle and with their tips facing the cylindrical wall of the milling chamber wherein the axle is coaxial with the cylindrical wall and such that the hammers rotate in the milling chamber along the cylindrical wall with their tips at a distance from same cylindrical wall over the full rotation of the hammers, and whereby at least part of the cylindrical wall of the milling chamber opposite the rotating tips of the hammer blades is a perforated screen, characterised in that at least part of the perforated screen can be opened and closed to release the content of the milling chamber.

[0051] Preferably at least part of the perforated screen can slide in the direction following the shape of, preferably parallel to, the cylindrical wall to open or close the milling chamber to release the content of the milling chamber. This sliding movement can be done manually, but is preferably done with an actuator for opening and closing the milling chamber.

[0052] Preferably the opening and closing is done in an automated process in sequence with the filling of the milling chamber with new feedstock.

[0053] Preferably the hammer mill device according to the invention, has an inlet tailored to the pre-sized automotive trim waste shreds or chips. The hammers, either in the form of blocks at the end of arms, or disks with plate like protrusions or blades or similar devices are rotating along an axle and along an inner wall of the milling chamber without touching the inner surface of the wall. Preferably a row of hammer blades are used, that are spatially organised on a rotating axle such that the hammer blades are rotating in the milling chamber along the cylindrical wall with their tips set at a distance from the same cylindrical wall over the full rotation of the hammers. The space between the wall surface or crushing plates, and the tip of the hammers may be adjustable to optimise the performance of the mill.

[0054] In the direction of the rotation of the hammers, the wall of the milling chamber is divided in zones.

[0055] In a first zone the wall is closed and preferably cladded with blades or bars or crushing plates to obtain a high impact zone against which the entering feedstock is smashed. As the backing layer is more brittle than the surface layer, these first impacts already provoke a first breakage/separation of the backing layer. At the same time the closed wall bounces the chips back into the turning circle of the hammers, preventing them from forming a stagnant layer outside the reach of the rotating hammers.

[0056] In a second zone one or more grates or perforated plates are aligned to form a separation area, whereby the smaller particles broken off can exit the milling chamber through the perforated plates, while the remaining bigger pieces are further hit and broken up by the action of the rotating hammers and of the centrifugal force smashing them against the grate or perforated plates.

[0057] In a last zone, at the end of the turn, the wall may be inclined such that the remaining material can freely fly off into a chute and thereby exit the milling chamber. Alternatively the last zone is having a perforated plate that may be moved away to create an exit for the material remaining inside the milling chamber. The plate may be moved away from the cylindrical wall or may slide parallel to the wall following the curve or shape of the cylindrical wall to form a temporary opening and is turned back to its initial position to close the milling chamber again. Underneath the perforated plate material passing through the plate is guided to collectors. Collectors may be any container suitable to retain the material fraction received. In addition the device may comprise a dust extraction system to prevent any dust from escaping in the air surrounding the device. The dust gathered may be used together with the fraction passed through the perforated plate and can be recycled together.

[0058] In case the exit for the remains in the milling chamber is a moving or opening perforated plate, a guiding system with a moving flap may be used to guide the material fraction into a separate collector, to keep the sieved fraction separate from the fraction coming from the milling chamber directly.

[0059] Depending on the dwelling time needed for breaking and pulverizing the TPO backing layer, while maintaining the surface layer flakes, the entrance to the chute may have a panel or door that may be opened and closed. Hence, the emptying of the main milling chamber may be operated in an intermittent process, preferably the feeding and the emptying are alternated to optimise the efficacy.

[0060]

[0061] In a preferred device according to the invention a side panel is integrated in the area of the last panel of the grid or sieve enabling a movement of the grid and opening the milling chamber. Whereby the sieve or grid plate may be moved parallel to the milling chamber or as a trap door away from the wall preferably to the outside.

[0062]

[0063] Preferably this zone comprises a perforated plate as well and would normally separate fraction A from the milling chamber, but a mechanism is put in place to either open this zone to manually release fraction B and or the perforated plate can slide aside or in the direction of the hammers rotation to create a temporary opening that lead into a separate waste retriever for material fraction B. The sliding or opening of the last zone may be aided with an actuator, optionally combined with automatic control units and or a computer-controlled system. The retrieval of material fraction B from the milling chamber may be aided with an air system, and such material fraction may be either purged, vacuum suctioned or blown out of the chamber. The movement of the hammer blades might generate enough centrifugal energy and air movement that material fraction B is removed from the milling chamber or at least support the removal when the exit door or flap is opened.

[0064]

[0065] The device according to the invention may comprise a double-passage system to collect fraction A - the fraction passing the perforated plate - and B - the fraction remaining inside the milling chamber - separate in appropriate collectors. In case of a sliding system for the opening and closing, an additional moving guide panel or flap may be used, in the passage system to guide the each collected fraction to the right collector. This panel or flap may comprise its own actuator or may be combined with the one opening and closing the wall. Example

[0066] During the production of flooring parts for vehicles including the bilayer, waste in the form of cut offs, cut outs, end of roll material and rejected parts were collected and cut into shreds of around 15 to 30mm forming the waste feedstock F. This material was fed into a device according to the invention with multiple rotating hammer blades with blunt edge sides and tips.

[0067] The device was fed batch wise with feedstock and the dwell time was kept constant.

[0068] From an initial mixed of bilayer material consisting of a TPO surface layer with no filler and a TPO backing layer with high filler content waste material of 212 kg with 93% of backing layer material was collected. By the process according to the invention and with the device according to the invention, it was possible to retrieve 81 % of the backing layer material as a separate fraction A. This is already a high yield considering that the process was not fully optimised yet. In particular, by further adapting the settings of the device, like speed, distance between tip of the wall and the hammer shape and size, a further increase in yield may be expected. The backing material fraction A was successfully used as filler in the production of a new backing layer. Fraction B could be further cleaned by an additional sieving step.

[0069]

[0070] Figure 1 shows a cross-section of the trim part providing the waste feedstock for the recycling process according to the invention.

[0071] Figure 2 is a process flow-sheet for a process according to the invention.

[0072] Figure 3 shows a device for the recycling process according to the invention.

[0073] Figure 4 shows a device according to the invention

[0074]

[0075] Floor coverings used in the automotive industry and known as TPO floorings may comprise one or more layers comprising thermoplastic elastomeric polyolefin (TPO) compound materials combined to form a scratch-resistant and durable surface layer, which may also be coloured and/or patterned to improve visual appearance. Such a surface layer may be combined with a heavier backing layer, i.e. comprising a high content of fillers.

[0076] Figure 1 shows a cross section of such TPO flooring for automotive vehicles with a large load floor area, in particular for a truck or SUV type vehicle. Such trim part comprises an aesthetic surface layer 1 comprising a thermoplastic elastomeric resin based material with a filler content of less than 5% by weight and an adjacent backing layer 2 comprising a thermoplastic elastomeric polyolefin based material with a filler content of at least 55% by weight, more preferably above 80% by weight, and preferably not more than 95% by weight. Both layers together form the bilayer.

[0077] For such trim part the thermoplastic elastomeric resin based surface layer 1 is typically made of a polypropylene based TPO material with zero or low filler content. The visible side of the surface layer 1 is embossed to obtain a decorative and anti-slip flooring surface.

[0078] The TPO material for the surface layer 1 or the backing layer 2 is preferably based on a compound comprising a polyolefin elastomer resin, a filler, for instance CaCOs, and optionally other polyethylene or polypropylene based resins, like low-density polyethylene (LDPE), Linear low-density polyethylene (LLDPE) or high-density polyethylene (HDPE).

[0079] The backing layer may have a density of between 1 .4 and 1 ,75kg/dm ³ and an area weight of up to 3 kg/m ² .

[0080] The surface layer 1 is more preferably made of a polypropylene based TPO material with zero or low - less than 5% by weight - filler content.

[0081] The backing layer 2 is comprising between 70 and 95% by weight of inert filler material, like for instance CaCOs and a thermoplastic elastomer matrix. The thermoplastic elastomeric matrix may be based on polypropylene (PP) based material or a combination of PP with LDPE, LLDPE or HDPE.

[0082] Both the materials comprised in the surface or the backing layer may be based on a different material mix, while they may further comprise other additives to further enhance the mechanical or aesthetical features required for the function of the layer. [0083]

[0084] The trim part may optionally comprise additional layers on the side facing away from the driver compartment or load compartment. This might be a soft foam layer, like a polyurethane foam layer or felt layer that may be removed before the separation step in the hammer mill.

[0085]

[0086] Figure 2 and 3 show a preferred process according to the invention comprising the steps of

[0087] (Stepl) collecting automotive trim part waste W comprising a thermoplastic elastomeric resin based material with a filler content less than 5% by weight and backing layer comprising a thermoplastic elastomeric polyolefin based material with a filler content of at least 55% by weight, more preferably above 80% by weight, and preferably not more than 95% by weight, preferably pre-cut into sizable pieces, forming feedstock F.

[0088]

[0089] (Step 2) Feedstock F is cut up in a shredder or cutting device Sh such that the cross-section in the dimension parallel to the layered structure is larger than the thickness of the structure. Hence they are preferably more like flat chips rather than cubical cut offs. This ensures that the surface layer after the backing layer is broken off stays in the milling chamber in the form of flakes while the broken off pieces of the backing layer, further pulverises and can pass through the grate or perforated plate. If the initial pieces are already small, the separated backing layer fraction may have a higher level of contamination.

[0090] (Step 3) the chips of shredded material F’ from step 2 are fed to a rotating hammer mill RHM, whereby the impact of the rotating hammers as well as the force with which the chips are smashed against the wall of the milling chamber, introduce an internal frictional stress within the material of the chips, while the surface material is able to react elastically on the stress, the high filler content of the backing layer is preventing such a reaction and the backing layer will crumble and separate from the surface layer. The backing layer will exit the rotating hammer mill via a sieve or grid and collected to form fraction A [0091] (Step 4) the surface layer will be collected from the milling chamber and forms fraction B.

[0092]

[0093] Figure 3 shows the same process with optional further process steps.

[0094] In case the waste of the trim parts comprises additionally a foam layer, the material may still be reduced in size according to step 2 but an additional cleaning step using a cyclone separator cy may be used to eliminate most of the foam contamination. The thus obtained Waste W' may be further recycled or reused.

[0095] Optionally the obtained material fractions A and B may be subjected to a melt filtration MF step to further eliminate debris D. Both fractions A and B can be reused in separate new TPO material layers for automotive trim parts ATP. These ATP may again produce waste that may be recycled. Hence the production can be seen as a closed loop production producing near to zero waste.

[0096] Figure 4 shows a cross-section of an example of the device according to the invention in more detail. Feedstock F’(according to the schemes in figure 2 and 3) is fed via an inlet 2 into the milling chamber 3 where hammer blades 4 are rotating. The tips of the hammer blades are moving along the cylindrical wall forming the milling chamber without touching. The feedstock is captured by the rotating blades and smashed against the wall of the milling chamber, which may also be formed by the grid, perforated plate or sieve 6 or by a special impact zone with bars 8 located at the wall to increase the initial impact. Due to the impact of the particles with the wall, the perforated plate or the blades, the backing layer material crumbles and disconnects from the surface layer material, while the surface material is elastic enough to remain in its initial form. The pulverised backing layer fraction A is separated through the holes 5 in the perforated plate or sieve 6 and leaves the mill as material fraction A, while the flakes of the surface layer is forming fraction B, that can not pass through the sieve and is staying inside the milling chamber. This fraction B may be released by a separate outlet 7, whereby the dotted lines indicate a possible moving outlet door. The retrieval of fraction B from the milling chamber may be done on different ways, this is just one example of for instance manual retrieval of the material fraction B.

[0097]

[0098] Figure 4 is showing a device according to the invention with

- a milling chamber 3 delimited by an essential cylindrical wall 12 and two side walls (not shown), and

- rotating hammer blades 4 spatially organised on a rotating axle 13 and with their tips 14 facing the cylindrical wall 12 of the milling chamber wherein the axle is coaxial with the cylindrical wall and such that the hammer blades are rotating in the milling chamber along the cylindrical wall with their tips at a distance from same cylindrical wall over the full rotation of the hammers, and whereby at least part of the cylindrical wall of the milling chamber opposite the rotating tips of the hammer blades is a perforated screen 11 , characterised in that at least part of the perforated screen 9 can be opened and closed to release the content of the milling chamber. The opening and closing may be for example in a sliding movement parallel to the cylindrical wall indicated with dashed arrows. In the collecting system underneath a flap or guide plate may be moved to guide the released material. During feeding the milling chamber and the actual milling process the broken-off and ground material will fall through the perforated plate and will be collected as fraction A. Upon opening the milling chamber by moving at least part of the perforated plate away, a flap or guide plate may be moved such that the remainder of the material escaping the milling chamber, is collected as fraction B. This is material that would normally not pass the perforated plate. After emptying the milling chamber, the gap in the perforated plate is closed again and optionally the guiding plate or flap is moved back to its original position.

[0099] Both the movement of the perforated plate to form a gap and the flap or guiding plate 10 may be automated, for instance with actuators and preferably with a computer programme. The control may be done in sequence with the filling of the milling chamber.

[0100] Preferably all steps are placed in a continuous line or at least in a single facility, however, this is not necessary. The steps may be separated in time and/or in space. The pre-separation and/or reduction in size may be done close to the automotive trim part production, while the process step 3 with the device according to the invention and further clean up steps may be done in another - preferably more central - facility. The waste may be gathered from different locations, and the reclaimed fraction may be used again on different locations. Although less beneficial, the surface fraction B now no longer containing the fraction with the high filler content may be more valuable for heat production and may be used as such. This would still result in a massive reduction in landfill as fraction A forms the larger fraction in most of the trim part waste available due to the high filler content.