CN119816405A - Method for recycling automobile elastic trim waste - Google Patents

Abstract

A method and apparatus for recycling waste materials from automotive decorative parts, wherein the automotive decorative parts include at least two layers consisting of a thermoplastic elastomer resin-based surface layer having a filler content of less than 5% by weight and a thermoplastic elastomer polyolefin-based backing layer having a filler content of more than 55% by weight.

Description

Method for recycling automobile elastic decoration waste

Technical Field

A method and apparatus for recycling waste material from automotive trim parts, wherein the automotive trim parts comprise at least a bilayer comprised of a thermoplastic elastomer resin-based surface layer having a filler content of less than 5% by weight and a thermoplastic elastomer polyolefin-based backing layer having a filler content of greater than 55% by weight.

Background

Floor systems for use in the cab of trucks and the loading floor areas of SUVs and minivans are traditionally made of polyvinyl chloride. Later, polyvinyl chloride was replaced with soft or abrasion resistant surfaces based on polyolefin-based materials. These aesthetic surface layers are primarily layers based on thermoplastic elastomer polyolefin, optionally embossed with a textured or patterned surface to increase durability and visual appearance, as well as to increase adhesion to the floor.

The thermoplastic elastomer resin-based surface layer may be up to 500gr/m ². It may comprise mainly a polyolefin resin, or may consist of a polyolefin resin, or may further comprise a very small amount of filler.

In general, in order to be able to cover the intended floor area well, a heavier backing layer may be laminated to the non-visible side of the surface layer. The backing layer is shaped together with the surface layer to cover an area dedicated to the floor covering portion. This may include curved regions as well as variations in the direction of flat regions to also encompass any channel or wall structure that needs to be seamlessly covered. Typically, the backing layer is also a thermoplastic elastomer polyolefin resin based (TPO) layer, but has different properties than the surface layer. In particular, it contains a large amount of inert filler such as CaCO ₃. The filler content may be between 55% and 98%. Furthermore, the weight of the backing layer used to hold the aesthetic layer to the floor can be as high as 4kg/m ³. At least 1.5kg/m ³ is required.

Although both layers are based on thermoplastic elastomeric materials, preferably thermoplastic elastomeric polyolefin (TPO) materials, the above-described differences between the surface layer and the backing layer make recycling difficult. In fact, the recycled mixture of surface layer material and backing layer material cannot be reused for producing the backing layer or for producing the surface layer, in which case the resulting backing layer will have a reduced mechanical stiffness, whereas in the case of producing the surface layer will have a reduced aesthetic value (due to the presence of filler) and a reduced durability. In both cases this will result in a layer unsuitable for producing e.g. a truck cabin floor covering decorative part.

Hammer mills are well known devices for recycling processes of various materials, which are used for the sole size reduction process step. All material fed into the milling chamber is crushed and passes through a grid or perforated plate in the lower region of the milling chamber.

It is therefore an object of the present invention to provide a method for recycling waste materials from automotive trim parts comprising at least a double layer consisting of a low filler content thermoplastic elastomer resin based surface layer and a high filler content thermoplastic elastomer polyolefin (TPO) based backing layer laminated together, which method enables the materials of the layers to be separated again and thus to be recycled separately.

Disclosure of Invention

The object herein is achieved by a method for recycling waste material from automotive trim parts according to the independent claim and the dependent claims thereof, and by an apparatus according to claim 15 and the dependent claims thereof, the automotive trim parts having at least a bilayer consisting of a thermoplastic elastomer resin-based surface layer with a filler content of less than 5% and a thermoplastic elastomer polyolefin (TPO) based backing layer with a filler content of more than 55%.

In particular, by a method comprising the steps of:

Step 1. Providing a raw material F consisting of automobile trim part scraps comprising at least a bilayer consisting of a thermoplastic elastomer resin-based surface layer having a filler content of less than 5% by weight and a thermoplastic elastomer polyolefin-based backing layer having a filler content of more than 55% by weight,

Step 2-forming a feedstock F' by reducing the feedstock F provided in step 1 into tablets, said tablets all having about the same size, measured at a maximum cross section parallel to the plane of the layer, between 5mm and 60mm, preferably between 10mm and 30mm, more preferably between 10mm and 15mm,

Step 3 feeding raw material F' into a rotary hammer mill, wherein the hammer rotates during the entire rotation of the hammer along at least one porous screen arranged at a distance from the end of the hammer, and wherein the hammer acts to fracture the backing layer and separate from the surface layer and is crushed into particles which are filtered by the porous screen or grid to form material portion a, while the surface layer is substantially not reduced in size and remains as a sheet in the milling chamber and forms material portion B, and

Step 4 removes material portion B from the milling chamber.

Surprisingly, the impact stress on a sheet comprising a double layer of a thermoplastic elastomer resin-based surface layer having a filler content of less than 5% and a TPO backing layer having a filler content of at least 55% caused by the impact of a hammer and any impact to the milling chamber wall introduces frictional stresses between the layers and within the layers and causes the polyolefin material of the backing layer to fracture, separate and crush from the surface layer while the thermoplastic elastomer polyolefin resin material of the surface layer remains substantially intact, enabling efficient separation of the two layers.

The high value surface material can now be recycled back into the surface layer production, while the leached portion of the backing layer material can be reused as filler in the backing layer production. Since the surface layer remains substantially intact, cross-contamination of the backing layer material portion and the surface layer material portion is reduced to such an extent that both portions are suitable for use in a recycling process of the respective layer, thereby solving the problems of the prior art.

The waste material of raw material F may include cut-outs, defective parts or material of the coil ends from the production of automotive trim parts comprising a double layer consisting of a thermoplastic elastomer resin-based surface layer having a filler content of less than 5% by weight and a thermoplastic elastomer polyolefin-based backing layer having a filler content of more than 55% by weight, and a trim part having an end of life. The bilayer may be used and produced as such, or the bilayer may be combined with an easily separable layer, such as a foam layer laminated thereto.

In principle, the cleaning waste produced before the use of the decorative parts in the motor vehicle can be used untreated, whereas the material with the end of its service life can preferably be used after the surface cleaning, in order to reduce any dirt or grease marks that might interfere with the final partial reuse.

Preferably, waste material from automotive trim parts production or from parts whose service life has expired may be cut into smaller pieces to fit the inlet of the machine used in the method of the invention. Optionally, an additional layer, such as a foam layer, preferably a polyurethane foam layer, may be separated, for example, by a tearing or scraping process before. A small amount of additional layers may still be present in the waste raw material F used in the recovery process according to the invention without reducing the efficiency of the process itself.

Step 2, comminution, may be carried out directly before the next step of the process according to the invention or may be carried out separately in time and/or space. In particular, it may be advantageous to perform such comminution at the production site of the automotive trim part, thereby minimizing the space required for storage and transportation.

The waste feedstock may be crushed or cut into flakes or chips using conventional grinders, crushers or cutters known in the art. In this step, the waste feedstock is only reduced in size, preferably with substantially no dust generation.

The bi-layer material, which is crushed into substantially equally sized flakes or chips, forms the feedstock F' of the third process step.

The raw material F in step 1 may comprise waste material from automotive trim parts, further comprising a foam layer attached to a backing layer. This waste material comprising the foam layer may be subjected to a further separation step wherein the crushed material produced in step 2 is passed through a cyclone separator to eliminate the foam fraction prior to step 3.

In alternative embodiments, different waste streams from the production of different decorative parts having at least one layer, preferably the same or compatible backing layer, may be combined to form feedstock F.

In an optional step, the portions a and B obtained from steps 3 and 4 may be melt filtered to eliminate any residual scrap and granulate the scrap. The pellets thus obtained can be used in subsequent extrusion or injection molding processes for the manufacture of other parts or layers for automotive or non-automotive applications.

The method may further comprise a step of pre-separating the bilayer from the additional layer, preferably prior to step 1. This is possible for example with a soft layer or surface binding layer which is not firmly bonded or entangled with the bilayer. These layers may be peeled or separated using, for example, a knife blade.

The thermoplastic elastomer resin material of the surface layer and/or the backing layer may comprise a thermoplastic elastomer polyolefin-based material, preferably a thermoplastic elastomer polypropylene, or a thermoplastic elastomer polyester-based material.

Preferably, the surface layer is a multilayer, wherein the main guiding layer or layer is formed of a thermoplastic elastomer resin material, and at least one layer of the outer layer is laminated to the backing layer. The additional layer may be a colored or patterned layer in combination with the sacrificial top layer. These layers are typically modified with additives (such as colorants, hardeners or softeners) to the basic thermoplastic elastomer resin material to obtain a multi-layer surface with different functional requirements.

The waste material may include a double layer consisting of an aesthetic surface layer of thermoplastic elastomer polyolefin (TPO) and a backing layer of thermoplastic elastomer polyolefin.

More preferably, the bilayer is comprised of a filler-free thermoplastic elastomer polyolefin (TPO) surface layer and a thermoplastic elastomer polyolefin (TPO) layer having a filler content of at least 55% by weight and not more than 95% by weight.

The thermoplastic elastomeric surface layer or backing layer may comprise an inert filler, preferably calcium carbonate.

The recycled part a or B from the process according to the invention may be fed in combination with the virgin thermoplastic elastomer material compatible with the part, thereby producing a thermoplastic elastomer layer, for example by means of an extrusion process. The layer thus produced can be used for automotive trim parts. Depending on the nature of the fraction and the newly defined layer, up to 30% (by weight) of the recovered fraction of the newly produced layer may be used.

Description of the embodiments

In the implementation of the method according to the invention, the automotive trim waste piece is picked up at the inlet of the hammer mill and is struck by an impact plate or a breaking block in the first region of the hammer mill due to the action of the hammer, wherein the crushed waste is bounced back into the region of the circulating hammer head. Preferably, a blunt hammer blade is used to increase the impact force. The waste pieces thus impacted can be picked up and slammed against the wall of the hammer mill or against a grating or perforated plate several times, wherein the shearing force between them and the hammers reduces the decorative waste pieces by breaking the high filling material of the backing layer off the low filling material of the surface layer and grinding the high filling material until the particles pass through the grating or perforated plate and leave the milling chamber. The remainder of the stock piece is mainly surface material which can be removed from the milling chamber via a separate outlet area. Alternatively, the ends of the grid or screen area have a larger opening size and the remainder of the chamber content may be purged through this final area.

Surprisingly, the separation of the low-filled thermoplastic elastomer resin material from the high-filled TPO material can be accomplished in a hammer mill device according to the present invention adapted to release the remainder from the milling chamber in a timely manner before the remainder is further degraded into powder or particles. Thus, only highly filled TPO material can be ground from the trim scrap pieces, while the low filled thermoplastic elastomer resin material flakes remain substantially intact until released from the grinding chamber via a separate outlet. Such an outlet may be a perforated grid or grid area of a perforated size large enough to release the pieces of material, or an outlet channel into which the remaining low-filled TPO material pieces are projected by the action of the hammer head and/or by the air flow generated in the milling chamber or by a portion of the milling chamber wall that can be opened and closed.

The residence time may be optimized to ensure that the surface material does not break and degrade into powder or particles. Surface material may be removed from the main milling chamber either manually or intermittently in an automatic mode. Alternatively, the last grid is sized so that all debris can fall through. This may be an area which is only temporarily opened for removal, but also ensures that the material is in the milling chamber for a sufficiently long time. The filling and emptying of the milling chamber may be a batch-wise batch process.

In the case of decorative parts comprising additional layers, such as foam layers on a backing layer, these layers may be separated beforehand, or the size of the decorative part waste comprising the foam layers may be reduced during the comminution process (i.e. step 2 of the method of the invention). In this case, an optional step may be introduced whereby the crushed material is separated in a cyclone to remove the foam fraction prior to step 3 of the method according to the invention.

The tip speed of the hammer blade and the distance of the hammer tip from the impact plate and grid can be optimized to ensure that sufficient breaking impact is generated on the particles to break the high packing material in a crushing manner.

The hammers in the hammermill are preferably blade-shaped with blunt edges. The blades may be arranged on a rotating shaft such that the ends of the hammer heads pass along the curved hammer mill wall at equal distances or at decreasing distances in the direction of rotation such that smaller particles cannot accumulate a layer between the porous screen and the heads, which may reduce the efficiency of the hammer mill. The shape of the outer blade with the side directly opposite the side walls of the milling chamber at the beginning or end of the shaft may be adapted to prevent the formation of hard lumps of material on these wall sides.

During rotation of the hammer, the waste material is picked up at the inlet and transported around. The surface portion will remain as a sheet in the milling chamber until manually removed or may be transported to an outlet positioned after the porous screen area, preferably just before the inlet area of the raw material when the direction of rotation of the hammer is concerned. This removal may be by means of a guide plate and may benefit from centrifugal forces on the sheet of surface material obtained by the action of the hammer. The surface sheet may be removed continuously or intermittently via the fiber outlet. Surface material can be removed from the milling chamber containing the hammer by means of a gas flow.

After the hammer mill process step, at least two main material portions are obtained, a portion B in the form of a sheet consisting essentially of the thermoplastic elastomer resin-based material of the surface layer and a portion A in powder or granulated form consisting essentially of the thermoplastic elastomer polyolefin-based material of the backing layer and the filler. The elastic material of the backing layer and its padding may be at least partly separated in the material portion a. Thus, the filler may be contained in part a in the form of separate particles.

Surprisingly, the difference in filler content between the two thermoplastic elastomer resin base layers allows for easy separation of the layers. In fact, a high filler content increases the brittleness or the tendency to collapse of the backing layer, while the lack of filler increases the elastic behaviour of the surface layer.

The invention further covers the apparatus for step 3 and step 4 of the method according to the invention. Step 3 is to put the raw material F' into a rotary hammer mill, wherein the hammer blades are rotated along at least one porous screen provided at a distance from the ends of the hammer blades throughout the rotation of the hammer, and wherein the hammer blades function to fracture the backing layer and separate from the surface layer and be crushed into particles which are filtered by the porous screen or grid to form the first material portion a without the surface layer being significantly reduced in size and remaining as flakes in the milling chamber and forming the second material portion B, and step 4 is to remove the portion B from the milling chamber.

Such an apparatus for recycling waste materials from automotive trim parts comprising a bilayer comprised of a thermoplastic elastomer resin-based surface layer having a filler content of less than 5% and a thermoplastic elastomer polyolefin-based backing layer having a filler content of greater than 55% comprises the following combination:

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

-A rotary hammer spatially arranged on a rotary shaft and with its tip facing the cylindrical wall of the milling chamber, wherein the shaft is coaxial with the cylindrical wall and causes the hammer to rotate in the milling chamber along the cylindrical wall, the tip of the hammer being at a distance from the same cylindrical wall throughout the rotation of the hammer, and wherein at least a portion of the cylindrical wall of the milling chamber opposite the rotating tip of the hammer blade is a porous screen, characterized in that at least a portion of the porous screen can be opened and closed to release the content of the milling chamber.

Preferably, at least part of the porous screen is slidable in a direction along the shape of the cylindrical wall, preferably parallel to the cylindrical wall, to open or close the milling chamber, thereby releasing the contents of the milling chamber. This sliding movement may be done manually, but is preferably done by an actuator for opening and closing the milling chamber.

Preferably, the opening and closing are performed in an automatic process, in sequence with filling the milling chamber with fresh material.

Preferably, the hammer mill device according to the present invention has an inlet customized according to pre-sized automotive trim waste chips or flakes. A hammer in the form of a block at the end of the arm, either in the form of a disc with plate-like projections or in the form of a blade or similar device rotates along the shaft and along the inner wall of the milling chamber, but does not contact the inner surface of the wall. Preferably, a row of hammer blades is used, which are spatially arranged on the rotation axis such that the hammer blades rotate along the cylindrical wall in the milling chamber, the tips of the hammer blades being set at a distance from the same cylindrical wall during the whole rotation of the hammer. The spacing between the wall surface or breaker plate and the end of the hammer can be adjusted to optimize mill performance.

In the direction of rotation of the hammer, the wall of the milling chamber is divided into a plurality of zones.

In the first zone, the wall is closed and preferably covered with blades or rods or breaker plates to obtain a high impact area against which the incoming material is bumped. These first impacts have caused the first break/separation of the backing layer, since the backing layer is more brittle than the surface layer. At the same time, the closed wall ejects the flaps back into the rotating ring of the hammer, preventing the flaps from forming a stagnant layer outside the range of the rotating hammer.

In the second zone, one or more grids or perforated plates are aligned to form a separation zone, wherein broken smaller particles can leave the milling chamber through the perforated plate, while the remaining larger pieces are further impacted and broken by the action of the rotary hammer and the centrifugal force, causing them to strike the grids or perforated plates.

In the final region, at the end of the rotation, the wall may be inclined so that the remaining material can fly freely out into the chute and thereby leave the milling chamber. Alternatively, the final zone has a perforated plate that can be removed to create an outlet for material remaining in the milling chamber. The plate may be moved away from the cylindrical wall or may slide parallel to the wall along the curve or shape of the cylindrical wall, thereby forming a temporary opening, and be rotated back to its original position, thereby closing the grinding chamber again. The material passing through the plate below the perforated plate is led to the collector. The collector may be any container suitable for holding the received material portions. In addition, the device may include a dust extraction system to prevent any dust from escaping into the air surrounding the device. The accumulated dust can be used together with the part passing through the perforated plate and can be recovered together.

In the case where the outlet of the residue in the milling chamber is a moving or open perforated plate, a guiding system with moving baffles may then be used to guide the material fraction into a separate collector to keep the screened fraction directly separated from the fraction from the milling chamber.

The entrance to the chute may have openable and closable panels or doors depending on the time that the TPO backing layer is broken and crushed while maintaining the residence time of the surface layer flakes. Thus, the emptying of the main milling chamber may be operated in a batch process, preferably with alternating feeding and emptying to optimise efficacy.

In a preferred arrangement according to the invention, the side panels are integrated in the region of the last panel of the grating or screen, enabling the grating to move and open the milling chamber. Wherein the screen or the grid plate can be moved parallel to the milling chamber or as a trapdoor preferably outwardly away from the wall.

Preferably the zone also includes a perforated plate and typically part a is separated from the milling chamber, but a mechanism is put in place to open the zone to release part B manually and either the perforated plate can be slid aside or in the direction of hammer rotation to create a temporary opening to a separate waste recycler for material part B. The sliding or opening of the final zone may be by means of an actuator, optionally in combination with an automatic control unit and/or a computer control system. Material portion B may be recovered from the milling chamber by means of an air system and such material portion may be purged, vacuum pumped or blown out of the chamber. The movement of the hammer blades may create sufficient centrifugal energy and air movement such that when the outlet door or flap is opened, material portion B is removed or at least supported for removal from the grinding chamber.

The device according to the invention may comprise a two-way system to collect the parts a (the parts passing through the perforated plate) and B (the parts remaining in the milling chamber) separated in a suitable collector. In the case of a sliding system for opening and closing, additional moving guide panels or baffles may be used in the pathway system to guide each collected portion to the correct collector. The panel or flap may include its own actuator or may be combined with an actuator to open and close the wall.

Example

During the production of vehicle floor parts comprising double layers, waste material in the form of cut-outs, coil end material and waste parts is collected and cut into pieces of about 15mm to 30mm, forming waste material F. The material is fed into a device according to the invention having a plurality of rotary hammer blades with blunt edge sides and ends.

The apparatus feeds the feedstock in batches and the residence time remains constant.

212Kg of waste material, 93% of which was backing layer material, was collected from an initial mixture of bilayer material consisting of a filler-free TPO surface layer and a high filler-content TPO backing layer. By means of the method according to the invention and the device according to the invention, 81% of the backing layer material can be recovered as separate part a. This is already a very high yield considering that the process is not yet fully optimized. In particular, by further adjusting the settings of the device, such as the speed, the distance between the wall ends, and the shape and size of the hammer, it can be expected that the yield will increase even further. The backing material portion a was successfully used as a filler to produce a new backing layer. Part B may be further cleaned by an additional screening step.

Drawings

Fig. 1 shows a cross section of a decorative part providing waste stock for the recycling method according to the invention.

Fig. 2 is a process flow diagram of a method according to the invention.

Fig. 3 shows an apparatus for the recovery method according to the invention.

Fig. 4 shows a device according to the invention.

Detailed Description

Floor coverings for the automotive industry known as TPO floors may comprise one or more layers comprising thermoplastic elastomer polyolefin (TPO) composites that in combination form scratch resistant and durable surface layers that may also be colored and/or patterned to improve visual appearance. Such a surface layer may be combined with a heavier backing layer, i.e. comprise a high content of filler.

FIG. 1 shows a cross section of a TPO floor for an automotive vehicle, particularly for a truck or SUV type vehicle, having a large loading floor area. Such a decorative part comprises an aesthetic surface layer 1 comprising a thermoplastic elastomeric resin-based material having a filler content of less than 5% by weight and an adjacent backing layer 2 comprising a thermoplastic elastomeric polyolefin-based material having a filler content of at least 55% by weight, more preferably more than 80% by weight, preferably not more than 95% by weight. The two layers together form a bilayer.

For such decorative parts, the thermoplastic elastomer resin-based surface layer 1 is typically made of polypropylene-based TPO material with zero or lower filler content. The visible side of the surface layer 1 is embossed to obtain a decorative and slip-resistant floor surface.

The TPO material for the surface layer 1 or backing layer 2 is preferably based on a compound comprising a polyolefin elastomer resin, a filler (e.g. CaCO ₃) and optionally other polyethylene or polypropylene based resins such as Low Density Polyethylene (LDPE), linear Low Density Polyethylene (LLDPE) or High Density Polyethylene (HDPE).

The backing layer may have a density of 1.45kg/dm ³ to 1.75kg/dm ³ and an area weight of up to 3kg/m ².

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

The backing layer 2 comprises 70% to 95% by weight of inert filler materials such as CaCO ₃ and thermoplastic elastomer matrix. The thermoplastic elastomer matrix may be based on polypropylene (PP) based materials or a combination of PP with LDPE, LLDPE or HDPE.

The materials contained in the surface layer or backing layer may be based on different material mixtures, while they may further contain other additives to further enhance the mechanical or aesthetic characteristics required for the function of the layer.

The trim part may optionally comprise an additional layer on the side facing away from the cab or cargo compartment. The additional layer may be a soft foam layer, such as a polyurethane foam layer or a felt layer, which may be removed prior to the separation step of the hammer mill.

Figures 2 and 3 show a preferred method according to the invention comprising the steps of:

(step 1) collecting automobile trim part scrap W comprising a thermoplastic elastomer resin-based material having a filler content of less than 5% by weight and a backing layer comprising a thermoplastic elastomer polyolefin-based material having a filler content of at least 55% by weight, more preferably about 80% by weight, preferably not more than 95% by weight, preferably the scrap being precut into substantial pieces to form raw material F.

(Step 2) the raw material F is cut in a pulverizer or cutting device Sh such that the dimension of the cross section parallel to the layered structure is greater than the thickness of the structure. They are therefore preferably more like flat flakes than cube-like cuts. This ensures that the surface layer remains in the milling chamber in the form of a sheet after the backing layer has been broken, while the broken pieces of the backing layer are further crushed and can pass through the grid or perforated plate. If the original piece is already small, the separated backing layer portion may have a higher level of contamination.

(Step 3) feeding the sheet F' of crushed material from step 2 to a rotary hammer mill RHM, wherein the impact of the rotary hammer and the force of the sheet striking the mill chamber walls introduce internal friction stresses in the material of the sheet, whereas the surface material is capable of elastically reacting to such stresses, the high filler content of the backing layer prevents such reaction, and the backing layer will collapse and separate from the surface layer. The backing layer will leave the rotary hammer mill via a screen or grid and be collected to form part a.

(Step 4) the surface layer will be collected from the milling chamber and form part B.

Fig. 3 shows the same method with optional further method steps.

In case the waste material of the decorative part additionally comprises a foam layer, the size of the material can still be reduced according to step 2, but an additional cleaning step can be performed using the cyclone cy to eliminate most foam contamination. The waste W' thus obtained can be further recovered or reused.

Optionally, the resulting material portions a and B may be subjected to a melt filtration MF step to further eliminate the debris D. Both parts a and B can be reused in a separate new TPO material layer for automotive trim parts ATP. These ATP may again produce waste that may be recovered. Thus, production can be regarded as a closed loop production with little scrap generation.

Fig. 4 shows a cross section of an example of a device according to the invention in more detail. Raw material F' (according to the scheme in fig. 2 and 3) is fed via inlet 2 into milling chamber 3 where hammer blades 4 are rotating. The tip of the hammer blade moves along the cylindrical wall forming the grinding chamber without contacting the cylindrical wall. The stock is caught by the rotating blades and jerks against the wall of the milling chamber, which may also be formed by a grid, perforated plate or screen 6, or by a special impact zone with bars 8 located on the wall to increase the initial impact. The backing layer material breaks apart and separates from the surface layer material due to the impact of the particles with the wall, perforated plate or blade, while the surface layer material is sufficiently elastic to retain its original shape. The crushed backing layer portion a is separated by the holes 5 in the perforated plate or screen 6 and leaves the mill as material portion a, while the flakes of the surface layer form part B, which cannot pass through the screen and remain inside the milling chamber. The portion B can be released through a separate outlet 7, wherein the dashed line indicates a possibly moving outlet door. Recovery of the material portion B from the milling chamber may be performed in different ways, which is only one example of e.g. manual removal of the material portion B.

Fig. 4 shows a device according to the invention with:

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

Rotary hammer blades 4 which are spatially arranged on a rotation axis 13 with their ends 14 facing the cylindrical wall 12 of the milling chamber, wherein the axis is coaxial with the cylindrical wall and causes the hammer blades to rotate along the cylindrical wall in the milling chamber, the ends of the hammer blades being at a distance from the same cylindrical wall throughout the rotation of the hammer, and wherein at least a part of the cylindrical wall of the milling chamber opposite the rotating ends of the hammer blades is a porous screen 11, characterized in that at least a part of the porous screen 9 can be opened and closed to release the contents of the milling chamber. The opening and closing may be a sliding movement, indicated by a dashed arrow, for example, parallel to the cylindrical wall. In the underlying collection system, a baffle or guide plate may be moved to direct the released material. During the feeding to the milling chamber and the actual milling process, the broken and ground material will fall through the perforated plate and be collected as part a. When the milling chamber is opened by removing at least a portion of the perforated plate, the baffle or guide plate may be moved such that the remaining portion of material escaping from the milling chamber is collected as portion B. These materials are materials that typically do not pass through the perforated plate. After emptying the milling chamber, the gap in the perforated plate is closed again and optionally the guide plate or the baffle is moved back to its initial position.

Both the movement of the perforated plate to form the gap and the movement of the baffle or guide plate 10 can be automated, for example by means of an actuator, preferably by means of a computer program. The control may be performed sequentially with the filling of the milling chamber.

Preferably, all steps are placed in a continuous production line or at least in a single apparatus, however, this is not essential. These steps may be separated in time and/or space. The pre-separation and/or size reduction may be performed close to the production of the automotive trim part, whereas the method step 3 and the further cleaning step using the device according to the invention may be performed in another apparatus, preferably in a more central apparatus. The waste material may be collected from different locations and the recovered fraction may be reused at different locations. Surface portion B, which now no longer contains a portion with a high filler content, may be more valuable for heat generation, although less beneficial, and may be used as such. This still results in a considerable reduction of the landfill volume, since, due to the high filler content, part a forms a larger part in most of the available trim part waste.

Claims (17)

1. A method for recycling waste materials from automobile decorative parts, wherein the automobile decorative parts include at least two layers, the two layers consisting of a thermoplastic elastomer resin-based surface layer having a filler content of less than 5% by weight and a thermoplastic elastomer polyolefin-based backing layer having a filler content of more than 55% by weight, the method comprising the following steps: - Step 1: providing a raw material F consisting of automobile decorative parts waste, the decorative parts waste comprising at least two layers consisting of a thermoplastic elastomer resin-based surface layer having a filler content of less than 5% by weight and a thermoplastic elastomer polyolefin-based backing layer having a filler content of more than 55% by weight; - step 2: forming a feedstock F' by reducing the feedstock F provided in step 1 into flakes, said flakes all having approximately the same size, measured at the largest cross section parallel to a plane of the layer, said size being between 5 mm and 60 mm, preferably between 10 mm and 30 mm, more preferably between 10 mm and 15 mm; - Step 3 Feeding the raw material F' into a rotary hammer mill, wherein the hammers rotate along at least one porous screen arranged at a distance from the ends of the hammers throughout their rotation, and wherein the hammers act to cause the backing layer to break and separate from the surface layer and be crushed into particles, which are filtered through the porous screen or grid to form material portion A, while the surface layer is not substantially reduced in size and remains as flakes in the milling chamber and forms material portion B, and - Step 4: Removal of material portion B from the grinding chamber. 2 . The method according to claim 1 , wherein the raw material F in step 1 further comprises a foam layer attached to the backing layer. 3. The method according to claim 2, further comprising an additional step, wherein the feedstock F' produced in step 2 is passed through a cyclone separator to eliminate a light foam fraction before step 3. 4. The method according to claim 1, wherein the raw material F used in step 1 is pre-cut into pieces. 5. The method according to any one of the preceding claims, wherein the material fraction A and/or the material fraction B from step 3 is further processed in a melt filtration step to obtain clean material fractions A and/or B and to eliminate any residual debris. 6. The method according to claim 5, further comprising a step of granulating the cleaned fractions A and/or B. 7. The method according to any of the preceding claims, further comprising pre-separating the bilayer from the additional layer, preferably before step 1. 8. A method according to any one of the preceding claims, wherein the thermoplastic elastomer resin based material from the surface layer comprises or consists of a thermoplastic elastomer polyolefin based material, preferably a thermoplastic elastomer polypropylene or a thermoplastic elastomer polyester based material. 9. A method according to any one of the preceding claims, wherein the surface layer is a multilayer and at least one outer layer of the multilayer is laminated to the backing layer. 10. The method according to any one of the preceding claims, wherein the surface layer is based on a thermoplastic elastomeric polyolefin material and the TPO backing layer is based on a thermoplastic elastomeric polypropylene material. 11. A method according to any one of the preceding claims, wherein the double layer consists of a surface layer and a backing layer, the surface layer consists of a thermoplastic elastomer polyolefin composite material with a filler content of 0-5%, and the backing layer consists of a thermoplastic elastomer polyolefin material with a filler content of 55-95%, preferably not more than 90%. 12. A method according to any one of the preceding claims, wherein the surface layer and/or the backing layer comprises an inert filler, preferably calcium carbonate ( _CaCO3 ). 13. Process according to any one of the preceding claims, wherein the recycled fraction A or B is combined with a thermoplastic elastomeric material compatible with this fraction to produce a thermoplastic elastomeric layer, preferably by means of a process comprising an extrusion step and/or an injection molding step. 14. The method of claim 13, wherein the recycled material fraction represents at most 30% by weight of the total extrudate. 15. A device for separating a double layer consisting of a thermoplastic elastomer resin-based surface layer having a filler content of less than 5% and a thermoplastic elastomer polyolefin-based backing layer having a filler content of more than 55%, the device comprising the following combination: - a grinding chamber delimited by a substantially cylindrical wall and two side walls, and - Rotating hammers spatially arranged on a rotating shaft and with their ends facing the cylindrical wall of the grinding chamber, wherein the shaft is coaxial with the cylindrical wall and causes the hammers to rotate in the grinding chamber along the cylindrical wall, the ends of the hammers being at a distance from the same cylindrical wall throughout the rotation of the hammers, and wherein at least a portion of the cylindrical wall of the grinding chamber opposite the rotating ends of the hammer blades is a porous screen, characterised in that at least a portion of the porous screen can be opened and closed to release the contents of the grinding chamber. 16. The apparatus according to claim 15, wherein at least a portion of the porous screen is slidable to form an open gap in a direction parallel to the cylindrical wall, thereby opening or closing the grinding chamber and enabling removal of the contents of the grinding chamber. 17. Apparatus according to claim 15 or 16, further comprising an actuator for opening and closing the grinding chamber.