Method for recovering materials from waste automotive trim parts

Abstract

Provided is a method for reclaiming materials from waste automobile trim parts having two layers including at least a layer of a thermoplastic elastomer compound material and a fiber layer, in which fibers of the fiber layer are entangled with the adjacent thermoplastic elastomer layer.

Description

[Technical Field]

[0001] The present invention relates to a method for recovering materials from waste automotive trim parts that contain at least two layers: a thermoplastic elastomer compound material layer and a fiber layer. [Background technology]

[0002] The automotive industry needs to become more sustainable by both increasing the use of recycled materials and reducing waste directed to landfills.

[0003] Noise-damping trim parts with multiple layers containing various types of materials are well known in the automotive industry. In these types of parts, a fibrous layer is typically combined with a thermoplastic elastomer layer to optimize acoustic or mechanical performance. These layers are often laminated together so that the materials are intertwined, making them difficult to separate for recycling purposes. One such product group consists of or includes a thermoplastic elastomer layer, such as a thermoplastic elastomer layer made of a thermoplastic elastomeric polyolefin (TPO)-based compound material, in combination with a fibrous layer, where the fibers of the fibrous layer are at least partially intertwined with the thermoplastic elastomer layer. The elastomeric material penetrates the fibrous layer and at least partially encapsulates the fibrous material. These types of bilayers are used, for example, as hard wear floor surfaces in trucks and vans, or as intermediate bilayers in acoustic components for sound insulation.

[0004] The thermoplastic elastomer layer may be of mixed inclusion: the thermoplastic elastomer layer may contain an inert filler material, and the thermoplastic component may be a combination of one or more types of thermoplastic materials, including polyester and / or polyolefin-based materials.

[0005] For example, EP 3812151 A1 discloses a noise-damping trim component for a vehicle, comprising a pile layer, a bonding mass layer, and a backing layer, with the bonding mass layer adhering to adjacent layers. The bonding mass layer comprises a thermoplastic elastomeric polyolefin-based compound material (TPO) having a filler content of at least 55%. Such bonding mass layers typically have a modulus of 1.4 to 1.75 kg / dm 3 density and 3kg / m 2 The function of the bonding mass layer is to connect with the pile layer and thereby bind the fibers and / or filaments and / or tufts within the pile. While good interlocking is necessary for good fiber bonding in the pile layer, a high degree of interlocking prevents easy separation of these layers for recycling.

[0006] Floor coverings used in the automotive industry, known as TPO coverings, contain one or more layers of compounded thermoplastic elastomeric polyolefin (TPO) materials to form a scratch-resistant and durable surface layer, which may be colored and / or patterned to improve visual appearance. Such a surface layer may be combined with a heavier backing layer, i.e., a backing layer containing a high filler content, corresponding to the bonding mass layer described above. Surface layers that can be combined with heavier backing layers may be manufactured directly on a textile or nonwoven carrier layer.

[0007] Manufacturing waste from parts containing this type of bi-layer material (e.g., waste resulting from defective parts, cut-offs, and roll end material) cannot be separated into a single original layer, creating problems for manufacturing waste management. This type of waste cannot be looped back into the manufacturing process and is not interesting for other known recycling or regeneration processes. Furthermore, the high inert filler content of the backing layer, greater than 55% by weight and typically reaching up to 85% by weight, can make this material less valuable for incineration. Therefore, it typically ends up in a landfill.

[0008] The most common techniques known and used today for recycling manufacturing waste from parts containing two layers of the type described above focus on size reduction, including knife milling / grinding, chipping, and shredding, with the goal of reducing the size of the manufacturing waste to small fragments that can be integrated into other types of layers as filler inclusions. However, the resulting product lacks added value. In one known method, the material is shredded to obtain small granules, which are then spread between two outer nonwoven layers. The resulting sandwich is then needled and can be used to manufacture automotive trim parts, such as flooring components or wheel well exterior liner structures. However, this type of process has the disadvantage that only a reduced amount of recycled material can be reintegrated into automotive trim parts. In addition, the shredded small granules can cause technical problems, such as needle breakage during needling. However, the biggest drawback of such a recycling process is that high-quality materials, such as polyester fibers contained in the fiber layers, are mixed with lower-value materials, thus reducing their value.

[0009] There are also processes aimed at separating carpet products, but these processes focus on products with thin adhesive layers rather than thick thermoplastic layers.

[0010] The low amount of high-quality materials like polyester in waste has hindered the efforts of established recycling companies to chemically separate the materials and create value-added waste streams.

[0011] To the inventors' current knowledge, there is no process on the market that successfully separates the fibrous material from the thermoplastic elastomeric polyolefin-based compound material (TPO) that forms the bilayer and allows the reuse of either this fibrous material and / or the thermoplastic material of this elastomeric layer. Summary of the Invention [Problem to be solved by the invention]

[0012] It is therefore an object of the present invention to provide a process for recycling waste materials containing a combination of multiple materials, including two layers of thermoplastic elastomer material and fibrous layers, which have been intertwined in the manufacturing process, as previously described. [Means for solving the problem]

[0013] (Summary of the Invention) This object is achieved by a method for recovering material waste from automotive trim parts comprising at least two layers, a layer of thermoplastic elastomer compound material and a fiber layer, according to the independent claim and the claims dependent thereon.

[0014] This object is achieved in particular by a method for recovering material waste from automotive trim parts comprising at least two layers, a layer of thermoplastic elastomer compound material and a fiber layer, the fiber layer and the adjacent thermoplastic elastomer layer being intertwined, the method comprising the following steps: Step 1: Providing a raw material consisting of waste from an automobile trim part including two layers consisting of a layer of thermoplastic elastomer compound material (TEC) and a fiber layer, wherein the layers are intertwined; Step 2: forming a feedstock F' by dividing the feedstock provided in step 1 into pieces all having approximately the same size, measured at the largest cross section parallel to the plane of the layer, of 5 to 60 mm, preferably 10 to 30 mm, more preferably 10 to 15 mm; Step 3: feeding the raw material F' into a rotary hammer mill, wherein the hammer head rotates along at least one perforated screen spaced from the tip of the hammer head throughout the entire revolution of the hammer, and the action of the hammer breaks down the thermoplastic elastomer compound material (TEC) and separates it from the fibrous material, resulting in a particle size that can be filtered through the perforated screen, thereby forming a first material fraction (hereinafter referred to as "TEC material fraction") consisting essentially of the thermoplastic elastomer compound material (TEC), while the remaining fibrous material remains in the milling chamber and forms a second material fraction X, wherein the fibers in fraction X are not substantially reduced in size; and Step 4: Removing fiber fraction X from the milling chamber.

[0015] Surprisingly, by using a hammer mill, it is possible to separate the thermoplastic elastomer compound (TEC) material from the fiber layer, and the resulting TEC material is sufficiently clean to be fed back into the TEC manufacturing process. Meanwhile, the fiber fraction can also be reused. By using a hammer mill as a size reduction and separation unit, it is possible to substantially maintain the initial length of the fibers, as determined by the initial particle size. The fiber fraction thus obtained can be used as a fiber material in a shoddy-type nonwoven material, preferably mixed with other fiber materials derived from recycled sources. However, as the concentration of high-value material increases, the material becomes interesting for standard recycling processes by external recycling companies or for incineration. For example, the short fiber fraction can be used as a filler in compound materials for non-automotive applications, such as building materials.

[0016] Surprisingly, the impact of the trim waste particles forming Feedstock F' against the walls and hammers of the hammer mill creates frictional stresses within the two layers. Because the TEC material is not strongly bonded to the fiber material, the TEC material breaks down and "springs off" from the fibers. By losing the TEC bonds, the fibers become less bound, but they are more flexible and primarily resist further breakage. The fibers are slightly cut or chopped, but remain essentially intact for most parts of the process.

[0017] The method can be further optimized by adapting the residence time during the hammer mill step, selecting the residence time so as to obtain good separation without substantial reduction in fiber length. The fibers are entangled in a loose mass of fibers and can be removed from the hammer mill chamber separately or through continuous or discontinuous process steps. Preferably, an opening can be integrated into the hammer mill, which allows the fibrous material to be periodically removed from the chamber, preferably using the already existing centrifugal force and the air flow generated by the rotation of the hammers. The opening can be opened at intervals just before reloading the milling chamber.

[0018] The fibrous material obtained in fraction X can be used in standard recycling processes dedicated to fibrous materials and / or as filler in automotive or non-automotive applications. [Brief explanation of the drawings]

[0019] [Figure 1] 1A and 1B show a cross section of an automotive trim part that includes at least two layers. [Figure 2] FIG. 2 shows a flow diagram of the main process according to the present invention. [Figure 3] Figure 3 shows a flow diagram of the main process including any additional washing steps. [Figure 4]FIG. 4 shows a schematic cross-sectional view of a rotary hammer mill. DETAILED DESCRIPTION OF THE INVENTION

[0020] The thermoplastic elastomer compound layer may be of mixed inclusion. The thermoplastic elastomer compound layer may contain an inert filler material, and the thermoplastic component may be a combination of one or more types of thermoplastic materials, including polyester and / or polyolefin-based materials. Preferably, the thermoplastic elastomer layer is a thermoplastic elastomer polyolefin-based layer (TPO layer) and comprises thermoplastic elastomer polyolefin (TPO) as the base compound forming the majority of the material, or as the main matrix component in the case of filled or highly filled layers.

[0021] For example, the flooring surface layer may be based on a polypropylene thermoplastic elastomer layer (PP-TPO) extruded onto or compressed together with a fibrous backing layer.

[0022] The thermoplastic elastomer compound layer (TEC) may be a highly filled TEC layer containing up to 90% by weight filler and may be molded with at least one fiber layer to form a mass layer for an acoustic trim component.

[0023] If the trim parts include additional layers, such as a foam layer, these can be pre-separated from the two-layer structure or the size of the trim part waste including the foam layer can be reduced in step 1. An optional step can be introduced to separate the shredded material in a cyclone separator to remove the foam fraction before step 2.

[0024] Both the TEC and X fractions recovered from the hammer mill can be subjected to a further separation process, preferably a sieving process, to remove small fibrous materials. Dust generated during hammer milling can be collected along with the TEC fraction.

[0025] All TEC fractions recovered from the hammer mill and / or from any subsequent screening steps may be subjected to a melt filtration step to remove any remaining debris and the final TEC fraction may be pelletized.

[0026] The regenerated TEC fraction can be fed into a TEC extrusion process, optionally combined with virgin and / or other source TEC material, to produce a TEC layer, which can again be combined with a fiber layer to form a bilayer structure. Preferably, the regenerated TEC fraction can be up to 30 wt% of the total TEC extrudate.

[0027] The fiber fraction can be incinerated or incorporated into fiber layers, compound layers, or interlayers for the production of automotive trim parts.

[0028] The TEC layer containing the recycled TEC and the fiber layer, compound layer, or intermediate layer containing the recycled fiber can be reused in an automobile trim part.

[0029] As used herein, a thermoplastic elastomer compound layer (TEC), preferably a polyolefin-based compound (TPO) layer, is a layer primarily based on a thermoplastic elastomer material. This layer can be used as either a decorative surface cover or a film, and can be combined with a fibrous nonwoven fabric layer on the backside to allow adhesion to additional layers. The combination of the TEC surface layer and the fibrous backing layer forms a two-layer structure for automotive floor or covering parts, such as flooring, cladding, or side trim.

[0030] Such a TEC surface layer can comprise, for example, an elastomer composition containing a very low density ethylene polymer component and / or a propylene polymer component. It can further comprise additives and coloring dyes to achieve a more or less glossy appearance and to achieve decorative patterns or colors. Furthermore, the layer can be embossed to form a decorative surface. The TEC surface layer can comprise two or more layers, where at least the main layer is a thermoplastic elastomer compound material (TEC) layer, to which a sacrificial top layer or coating, which can also be based on polyolefins, can be applied. The TEC surface layer is preferably a PP or PE elastomer TPO layer.

[0031] Alternatively, thermoplastic elastomer compound materials (TECs) can be found as backing layers or mass bonding layers in automotive insulating trim components. The TEC-based material may be a thermoplastic elastomer polyolefin-based compound material (TEC) having a filler content of at least 55 percent. Such layers typically have a ductility of 1.4 to 1.75 kg / dm 3 and a density of 3 kg / m 2 The polyolefin may be a polypropylene or polyethylene based polymer.

[0032] The fibrous layer may be a fibrous nonwoven used as a decorative covering layer for trim components, or may be used as a carrier layer during the manufacture of the mass / backing layer itself. The fibrous layer may be a nonwoven or scrim layer based on staple fibers or endless filaments. Staple fibers with an average length of 10 to 60 mm, preferably 20 to 35 mm, are preferably used. The fibrous layer may comprise any fiber or fiber mixture based on artificial or natural fibers. Preferably, the fibers are based on polymers or copolymers of polyester, polyamide, or polyolefin, or polylactic acid, or on animal fibers such as wool, or on cotton, hemp, flax, or similar plant fibers. Preferably, the fibrous layer is based on polyester, preferably a terephthalate-based polyester.

[0033] The TEC layer may be a combination of multiple TEC layers. In such a structure, at least one of the TEC layers is intertwined with a fiber layer to form a bilayer structure. In certain embodiments, at least one of the TEC layers may include a filler material. However, in this regeneration process, the multilayer TEC structure can be fully processed without the need to separate the TEC layers.

[0034] As used herein, "a thermoplastic elastomer compound (TEC) layer intertwined with a fiber layer" means that the fibers of the fiber layer are at least partially encased in the thermoplastic elastomer compound (TEC) material, such that it is no longer possible to separate the two materials without destroying the structure of the layers. In most cases, the two-layer structure is not even visible. Thus, the two layers can be perceived as a single layer.

[0035] A source of bi-layer waste pieces is provided, comprising at least a layer of thermoplastic elastomer compound material (TEC) entangled with a layer of fiber. The bi-layer waste originates from the manufacture of automotive trim components, such as flooring components, cladding, or panels, and comprises a bi-layer consisting of at least a layer of TEC entangled with a layer of fiber. This entanglement is related to the process of manufacturing such layered materials, in which the TEC is either directly extruded onto a fiber carrier layer or the layers are compressed together by a thermoforming process, forming a bi-layer material that can no longer be separated into a single layer.

[0036] The bilayer material for the feedstock may be cut-offs, cutouts, defective parts, or roll end materials, and end-of-life automotive trim parts, in the manufacture of automotive trim parts comprising a bilayer consisting of a thermoplastic elastomer compound material (TEC) layer and a fiber layer. This bilayer may be used and manufactured as is, or may be combined with an easily separable layer, such as a foam layer, laminated thereon. The method of the present invention may include a preliminary separation step to remove any other layers from the bilayer, such as a shaving or splitting step with a knife blade.

[0037] For example, the bilayer forming the waste feedstock can consist of a TPO decorative surface layer and a fibrous backing layer for covering a surface in an automobile or truck, where the fibrous layer is intertwined with the TPO decorative surface layer on at least the backside of the TPO layer. The TPO layer can be a single layer or a combination of multiple layers.

[0038] Another example of a bi-layer forming the waste feedstock may be a fibrous surface layer, such as a nonwoven fabric layer or a needle-punched carpet layer, with a thermoplastic elastomeric polyolefin-based compound material (TPO) backing layer, also known as a mass layer or overlay, which may contain up to 95% by weight of filler.

[0039] In general, the TEC layer can be a film or a foil.

[0040] The TEC layer can be foamed with, for example, a polyurethane type foam in an injection foaming process.

[0041] A TEC layer can be sandwiched between two fiber layers to form a trilayer, which can be processed in the same way as a bilayer material.

[0042] The fibrous nonwoven may comprise a staple fiber or endless filament nonwoven material based on natural and / or synthetic fibers or fiber blends, and may preferably comprise a polyester, preferably polyethylene terephthalate (PET), a polyolefin such as polypropylene or polyethylene, or a polyamide such as polyamide-6 or polyamide-6,6.

[0043] The bi-ply waste preferably does not contain latex such as polyvinyl chloride (PVC) and / or styrene-butadiene resin (SBR).

[0044] In principle, any TEC layer combined with fiber layer-forming waste from the automotive industry can be used as raw material for the process of the present invention. In principle, clean waste generated before trim parts are used in automobiles can be used without treatment, while end-of-life materials can be used preferably after surface cleaning to reduce any dirt or grease that may prevent the reuse of the final fraction.

[0045] Preferably, waste from the manufacture of automotive trim parts or from end-of-life parts can be cut into smaller pieces of smaller size as defined by the inlet of the device used in the method according to the invention. Any additional layers, such as a foam layer, preferably a polyurethane foam layer, can be separated beforehand, for example by a splitting or shaving step. Small amounts of additional layers may still be present in the waste material used for the recycling process according to the invention, without reducing the effectiveness of the process itself.

[0046] The waste material is chopped or cut into pieces all having approximately the same size, between 5 and 60 mm, preferably between 10 and 30 mm, and more preferably between 10 and 15 mm. This chopping or cutting operation is preferably accomplished with minimal shearing of the waste material, thereby preventing powder formation and / or cutting of fibers to sizes smaller than the cutting size and / or plastic deformation of the TEC material.

[0047] This shredding can take place immediately before the next step of the method according to the invention or can be separated in time and / or space, and in particular it can be advantageous to carry out this shredding already at the manufacturing site of the automotive trim parts, minimizing the space required for storage and transport of the waste raw pieces.

[0048] The shredding or cutting of the waste material into small pieces can be carried out using conventional grinders, shredders, or cutters known in the art. In this step, the waste material is preferably only reduced in size without substantially generating dust. Instead of pre-separation, an additional layer, such as a foam layer, can be broken into smaller pieces along with the bilayer, and in the same step, this additional layer can be separated using a cyclone separator or any other technique capable of separating light and heavy material particles. The fraction containing the bilayer material shredded into substantially equal-sized pieces forms feedstock F' for the second process step.

[0049] The shredded feedstock F' is fed into a rotary hammer mill, where the hammer rotates along at least one perforated screen positioned at a distance from the tip of the hammer throughout the entire hammer rotation. The action of the hammer breaks down the thermoplastic elastomer compound material (TEC), separating it from the fibrous material and reducing it to a particle size that can be filtered through the perforated screen or grid, thereby forming a first material fraction consisting essentially of TEC. Meanwhile, the remaining fibrous material remains in the milling chamber and forms a second material fraction X, where the fibers in fraction X are not substantially reduced in size throughout the process. Depending on the perforations in the screen, the TEC fraction may be further divided into multiple material fractions consisting essentially of TEC-based material. A concentrated crushing zone can be created by rods or blades in a first region of the curved wall of the hammer mill, immediately in front of the perforated screen, allowing for stronger impact of flying pieces / particles on the wall. Preferably, the system is designed so that the shear energy is insufficient to melt the TEC-based material.

[0050] In an additional step, or together with the previous step, the fibrous material is removed from the milling chamber.

[0051] The hammers in the hammer mill are preferably blades with blunt edges. Multiple blades can be arranged on a single rotating shaft, so that the tips of the hammer heads pass along the curved hammer mill wall at equal or decreasing distances in the direction of rotation, preventing smaller particles from forming a layer between the perforated screen and the head that would reduce the effectiveness of the hammer mill. The outer blades, located at the beginning or end of the shaft and with one side directly facing the side walls of the milling chamber, can be shaped to prevent material cakes from forming on these walls.

[0052] During the rotation of the hammers, the waste material is picked up at the inlet and transported to the periphery. The fiber fraction may remain in the milling chamber until manually removed, or may be transported to a fiber outlet, which, relative to the direction of rotation of the hammers, is preferably directed immediately before the material inlet area and after the area with the perforated screen. Removal may be assisted by a guide plate and may benefit from the centrifugal force on the fiber material obtained by the action of the hammers. Fibers may be removed continuously or intermittently through the fiber outlet. Removal of the fiber material from the milling chamber, including the hammers, may be assisted by an airflow.

[0053] After the hammer mill process step, at least two main material fractions are obtained: a TEC fraction and an X fraction. The TEC fraction contains primarily TEC-based materials in particulate or powder form. This fraction can be directly reused in the TEC-based material process or can be further cleaned in a melt-filtration step before being used in the TEC-based manufacturing process.

[0054] At least the TEC fraction can be reused in the process from which the material originated. This may be, for example, the production of TEC flooring or the production of a mass or backing layer. In particular, it has been shown that in the production of a mass or backing layer, the recycled TEC fraction can be used as a filler fraction without degrading the quality of the product or the overall properties of the trim part produced thereby. Conversely, the recycled material is not readily noticeable in the product or its properties.

[0055] The fiber fraction can be sieved in a second process step, for example in a cyclone separator, to effect further separation of the fiber material from any material that has not yet been completely separated, which can be fed back to the hammer mill for further separation. [Example]

[0056] Examples of regeneration methods according to the present invention During the manufacture of two-ply vehicle flooring components, waste materials in the form of off-offs, cut-outs, roll material ends, and rejected parts were collected and cut into approximately 15-30 mm pieces to form Waste Feedstock F. This material was fed into a hammer mill equipped with a number of rotating hammer blades having blunt cutting edges and points.

[0057] The raw material was fed batchwise into a laboratory hammer mill to maintain a constant residence time.

[0058] From 1 kg of mixed TPO / fiber initial waste with 78% TEC material, it was possible to recover 82% TEC material as a separate fraction. This is already a high yield considering that the process has not yet been fully optimized. Further increases in yield can be expected by further adapting the hammer mill settings, especially the speed, the distance between the wall and the hammer tip, and the shape and size of the hammer.

[0059] Figure 1 shows two different layout examples for an automotive trim component structure that includes two layers. Depending on the function of the TEC layer and the fiber layer, the two layers can be visible from one side of the passenger compartment or hidden in the trim.

[0060] More generally, the fibrous layer can have a variety of functions in automotive trim parts, such as a carpet-type surface layer (as shown in FIG. 1B), an airflow resistance layer, a decoupling layer, or a technical function, such as to prevent sticking of a TEC layer (as shown in FIG. 1A) or to increase the mechanical properties of the layer.

[0061] FIG. 1A shows a cross-section of a TPO flooring 10 for automotive vehicles with large load areas, particularly trucks or SUVs. Such TPO flooring is typically made of a polypropylene-based TPO material with zero or low filler content. The TPO flooring 10 includes a two-layer structure consisting of a thermoplastic elastomer layer 20 and a fibrous backing layer 30. For such applications, the thermoplastic elastomer layer 20 is typically made of a polypropylene-based TPO material with zero or low filler content. The surface of the TPO layer 20 is embossed to provide a decorative, non-slip flooring surface. The fibrous backing layer is intertwined with the TPO surface layer, making it impossible to separate these layers without destroying them. The TPO material penetrates between the fibers and at least partially encapsulates the fibers of the fibrous layer.

[0062] The TPO material for the surface is preferably based on a composite comprising a polyolefin elastomer resin, a filler such as CaCO3, and optionally other polyethylene or polypropylene based resins, low density polyethylene LDPE, linear low density polyethylene LLDPE, or high density polyethylene HDPE.

[0063] The fibrous nonwoven may comprise a staple fiber or endless filament nonwoven material based on synthetic fibers or fiber blends, and may preferably comprise a polyester, preferably polyethylene terephthalate (PET), a polyolefin such as polypropylene or polyethylene, or a polyamide such as polyamide-6 or polyamide-6,6.

[0064] Alternatively or additionally, the fibrous layer may comprise natural fibres such as wool, hemp, cotton, flax, or any other fibrous material of natural origin.

[0065] The staple fibers may comprise a mixture of different fiber materials and / or may comprise regenerated or recycled fibers.

[0066] Furthermore, the fibrous layer may contain a binder, for example, in the form of binder fibers or in the form of a powder, based on the same or similar materials as those mentioned for the staple fibers. Preferably, the binder is compatible with the selected staple fibers, so that mixed recycling is not a problem. For example, a polyester-based fibrous material is compatible with both polyester and staple fibers based on polyester, preferably terephthalate-based polyester.

[0067] The fibrous layer may be a spunbond nonwoven layer of endless filaments, preferably of terephthalate-based polyester.

[0068] 1B shows a three-layer structure typically used for sound attenuation, in which a TPO-based layer 40 forms the mass layer and a soft foam layer 60 forms the spring layer. Together, both layers function as an acoustic mass-spring system that acts as sound insulation when placed inside a vehicle. The surface layer can be a simple nonwoven layer 50 or a needle-punched nonwoven carpet layer. The TPO-based layer can be extruded against the fibrous layer, thereby at least partially enveloping the fibrous layer and forming a two-layer structure that can no longer be separated into a single layer.

[0069] The materials used in the two-ply construction are, in principle, comparable to those listed above for flooring construction. The actual polyolefin resin used can vary, as can the filler content. The function of the mass layer is related to the high-density material, and therefore higher filler contents can be achieved for these TPO-type layers. These TPO-based overlays or mass layers are known to be used between other layers to form airtight barriers with high areal weights. To achieve this with minimal thickness, highly filled materials are used. Thus, a typical TPO-based overlay material contains 70-95% by weight of an inert filler material, such as CaCO3, and a thermoplastic elastomer matrix.

[0070] The fibrous layer in the alternative acoustic layout according to Figure 1B may be a pile layer comprising fibers and / or filaments and / or yarns. This layer may be made from at least one polymer or copolymer selected from the group consisting of polyester, preferably terephthalate-based polyester, such as polyethylene terephthalate (PET), or polyamide, preferably polyamide-6 (PA6) or polyamide-66 (PA66), or polyolefin, preferably polypropylene (PP) or polyethylene (PE), or a mixture of two or more of these polymers and / or copolymers. The fibers, filaments and / or yarns may be based on bio-sourced, reclaimed or recycled materials or may comprise such types of feedstock.

[0071] Generally, the fibrous layer may be any fibrous layer, such as a nonwoven fibrous layer, or a scrim layer, and may have a density of 100 to 1500 g / m 2 The fibrous layer can include solid fibers, hollow fibers, binder fibers, or bicomponent fibers, as well as small percentages of non-fibrous materials such as foam chips or waste scraps.

[0072] Optionally, a foam layer, preferably a polyurethane foam layer, can be used as a backing layer. The foam layer can be laminated to the two-layer structure or applied in a reaction injection foaming process, in which the foam layer is foamed directly onto the surface of the bonding mass layer. A scrim can be placed between the two layers to allow molding of the bonding mass layer and increase adhesion between the layers. Alternatively, a soft fibrous layer can be laminated to the two layers; these softer layers are not intended to be enveloped by the TPO-based layer and are only laminated to the contact surface after the two-layer structure is manufactured. Therefore, these types of layers can be peeled or pulled away from the two-layer structure, leaving only a small amount of fiber.

[0073] Flooring such as that shown in Figure 1A and three-layer structures such as that shown in Figure 1B can be used to manufacture automotive trim parts. To manufacture such parts, two-layer or three-layer structures can be combined with additional layers and molded to create the shape necessary for the part to fit into a dedicated space in a vehicle. They can be used, either alone or in combination, as flooring and / or inner dash and / or surface coverings in the primary passenger compartment, and / or as flooring and / or side coverings in the trunk area, and / or as cladding, paneling.

[0074] Both product groups in Figures 1A and 1B belong to automotive trim parts that form part of the manufacturing and disposal cycle as shown in the process flowsheet that follows.

[0075] Cut-offs, cut-outs, rejected parts and / or end-of-life parts of automotive trim parts are considered waste W that can be used to feed the recycling or regeneration process according to the invention. For the method according to the invention, the two-layer structure is the core of the regeneration process, while additional layers are optional.

[0076] Any additional layers can be substantially removed by a separation process beforehand in order to discard such layers separately, which is more advantageous as these layers maintain their base material and are not further mixed with other materials.

[0077] Figure 2 shows the main process according to the invention as a first embodiment. The raw material F is provided by a waste stream W originating from the production of automotive trim parts ATP, where the main component of the waste stream is made up of cut-offs, cutouts, defects and ends of roll material, which comprises at least two layers, a thermoplastic elastomer-based compound material and a fibrous layer, as detailed in Figure 1 for example. The fibrous layer and the TEC layer are intertwined, so that they cannot be separated without damaging both layers.

[0078] The automotive trim part waste, as defined, is reduced in size to accommodate subsequent equipment and handling constraints and form the feedstock F for the reclaiming process. The feedstock F is fed to a size reduction machine Sh, such as a shredder, cutter, or similar machine, which is capable of cutting the feedstock into small pieces, preferably without substantially reducing the thickness of the bilayer and / or substantially altering its properties. In particular, the size reduction process should avoid exposing the feedstock to significant heat or pulverizing it into powder. Preferably, a size distribution substantially within a given range is obtained with low levels of oversized and undersized particles.

[0079] The raw material F' resulting from this shredding process should preferably have an average size of 3 to 60 mm, preferably 10 to 30 mm, more preferably 10 to 15 mm. The size of the cut or chopped pieces determines the maximum fiber size that can be achieved in subsequent steps. In principle, it is desirable to maintain larger fiber sizes, while high levels of comminution can reduce the effectiveness of the regeneration process.

[0080] It would be beneficial to introduce a size reduction step next to the automotive trim part production line so that any larger rejected parts could be reduced in size to optimize storage and transportation. This step could therefore be separate from the other steps, with smaller parts being stored and transported in large bags. However, it could be more economical and environmentally friendly to have all recycling steps close to the actual production of the automotive trim parts.

[0081] The raw material F' is fed to a rotary hammer mill, RHM. In the rotary hammer mill, the reduced size particles are crushed by rotary hammers, where the thermoplastic elastomeric polyolefin-based compound material is broken down and sieved to form a material fraction consisting essentially of TPO material, while the fibrous material, being a lighter and more flexible fraction, is able to entangle without substantial size reduction and remains in the milling chamber. This ability to entangle or remain in an entangled state with other fibers after removal of the TPO facilitates retention of the fibers in the milling chamber and reduces the likelihood of the fibers leaking through the provided sieve or grid.

[0082] The sieve plates in the chamber should be selected so that they do not allow fiber material to pass through, but allow broken TPO pieces / particles to pass. Optionally, a grading system may be introduced to separate the TPO powder and particle size fractions. Fiber fraction X can be removed from the milling chamber either continuously or discontinuously, or in a batch manner, depending on the fiber fraction in the original feedstock and the process throughput. The TPO fraction and / or fiber fraction X can be subjected to a sieving step Si to further purify the fiber fraction from the TPO fraction.

[0083] The TPO fraction can be fed back into the production of automotive trim parts ATP, for example as a filler in the TPO layer. Alternatively, the recycled TPO can be used to manufacture other parts or layers for automotive products, or can be used outside the field of automotive products.

[0084] This method can be further enhanced in several optional steps to further purify and / or clean the resulting fraction.

[0085] For example, the resulting TPO fraction can be subjected to a sieving step Si to remove any remaining fibrous material X, and this fibrous fraction can be combined with the fraction obtained from the milling chamber, depending on the quality of the fractions. The fibrous fraction can also be subjected to a sieving step to obtain any ground or particulate TPO.

[0086] The fraction can be looped back to the hammer mill for further cycles.

[0087] Optionally, to allow for better processing and transportation, the obtained TPO fractions (TPO, TPO") are preferably subjected to melt filtration MF to further purify them and pelletize them to form small particles. Any filtered impurities D can be discarded.

[0088] The granular TPO' thus obtained can be fed back into the production of the original TPO layer or into a suitable TPO product. The cut-off material from this or from the subsequent processing to create automotive trim parts can be fed back into the waste recycling process indicated by the arrow, making this a closed-loop process.

[0089] Surprisingly, it has been found that a melt filtration process under controlled temperature conditions reduces or eliminates benzene that may be released during TPO production or from the produced TPO layers, which was previously thought to be an obstacle to reusing reclaimed TPO material.

[0090] The recycling process according to the invention is sustainable, i.e., no other materials are introduced, and the waste stream dedicated to landfill can be substantially reduced, preferably to nearly 0% by weight. In particular, the low-cost inert filler can be completely recycled and reused as filler, while the fiber fraction weighs less and can be used in fiber layers for trim parts, or even increased in value for incineration.

[0091] Flow scheme Figure 3 illustrates a process equivalent to that shown in Figure 2 for a trim part containing at least three layers of material. The trim part, as with other processes, includes at least two layers, including a thermoplastic elastomer material and a fibrous layer, plus an additional layer in the form of polyurethane (PUR) foam, e.g., a rigid or semi-rigid foam layer, adjacent to either the TPO or fibrous layer. The waste from manufacturing such trim parts can be shredded without prior separation of the foam layer, or a first, rough pre-separation can be performed, for example, using a shaving or splitting process, e.g., with a knife blade (not shown). Alternatively, particularly if the foam is a substantially thin layer, the waste can be immediately reduced to smaller particles without prior separation. Because the PUR foam is a less strongly bonded material, it can be cut, peeled, or crushed from the two layers during size reduction, e.g., in a shredder or cutting device. The inclusion of a cyclone separator after size reduction allows for separation of lighter foam particles from heavier two-layer particles. The foam fraction thus obtained can be fed to a separate foam recycling system known in the art, while a smaller amount can be fed back into foam production as a precursor or foam filler, or used in other layers for automotive trim parts.

[0092] Figure 4 shows a cross section of an example of a hammer mill in more detail. The raw material F or F' (according to the schemes of Figures 2 and 3) is fed through an inlet 2 into a milling chamber 3, where a hammer blade 4 rotates. The tip of the hammer blade moves along the wall forming the milling chamber without touching it. The raw material is captured by the rotating blade and impacts the wall of the milling chamber. This impact can be formed by a grid or sieve 6 or by a special impact zone with bars 8 located in the wall to increase the initial impact. Due to the impact of the particles with the wall, sieve, or blade, the TEC material disintegrates and separates from the fibers, while the fibers are light and elastic enough to remain in tangled bundles. The TEC fraction is stripped from the fiber fraction X and crushed. This fraction is separated through the grid 6 and leaves the mill as a TPO fraction, while the fiber fraction X remains in the milling chamber and can be discharged through a separate outlet 7, where the dotted line indicates the possible movement of the outlet door. The collection of fibers from the milling chamber can be done in a variety of ways, this being just one example, e.g., manual collection of the fiber fraction.

[0093] Preferably, all steps are arranged in a continuous line, or at least on a single facility, although this is not necessary. These steps may be separated in time and / or space. Pre-separation and / or size reduction may be carried out near the automotive trim part production, while hammer milling and further cleaning may be carried out in a separate facility, preferably a more central facility. Waste can be collected from various locations, and reclaimed fractions can be used again in various locations. The less useful fiber fraction, which no longer contains the thermoplastic elastomer fraction, may be more valuable for heat generation and can be used as is.

Claims

1. 1. A method for recovering waste material from an automotive trim part comprising at least two layers, a layer of a thermoplastic elastomer compound material and a fiber layer, wherein the fiber layer and the thermoplastic elastomer layer are intertwined, comprising: The method includes the steps of: Step 1: Providing a raw material F consisting of waste from automotive trim parts comprising two layers, a layer of thermoplastic elastomer compound material (TEC) and a fiber layer, wherein these layers are intertwined; step 2: forming a raw material F' by dividing the raw material F provided in step 1 into pieces all having approximately the same size, measured in the largest cross section parallel to the plane of the layer, between 5 and 60 mm, preferably between 10 and 30 mm, more preferably between 10 and 15 mm; step 3: feeding the raw material F' into a rotary hammer mill, wherein the hammer head rotates over the entire revolution of the hammer along at least one perforated screen spaced from the tip of the hammer head, and the action of the hammer breaks down the thermoplastic elastomer compound material (TEC) and separates it from the fibrous material, reducing it to a particle size that can be filtered through the perforated screen, thereby forming a first material fraction consisting essentially of the thermoplastic elastomer compound material (TEC), while the remaining fibrous material remains in the milling chamber and forms a second material fraction X, wherein the fibers in fraction X are not substantially reduced in size; and Step 4: Removing the fiber fraction X from the milling chamber.

2. The method of claim 1 , wherein the feedstock in step 1 further comprises a foam layer attached to either the fiber layer or the TEC layer.

3. 3. The method of claim 2, wherein the waste material containing the foam layer is subjected to a further separation step, in which the shredded material from step 1 is passed through a cyclone separator to remove the foam fraction prior to step 2.

4. 2. The method of claim 1, wherein the waste material F used in step 1 is pre-cut into small pieces.

5. The method of any one of claims 1 to 4, wherein the TEC fraction from step 3 is subjected to a separation process, preferably a sieving process, to remove any remaining fibrous material.

6. 6. The method of any one of claims 1 to 5, wherein the TEC fraction from step 3 is subjected to a melt filtration step to remove any remaining debris and pelletized.

7. The method according to any one of claims 1 to 6, wherein the TEC material is a thermoplastic elastomeric polyolefin, preferably a thermoplastic elastomeric polypropylene, or a thermoplastic elastomeric polyester based material.

8. The method of any one of claims 1 to 7, wherein the TEC layer is multiple layers of thermoplastic elastomer, and at least one of the outer layers of the TEC layer is intertwined with a fibrous layer.

9. The method of any one of claims 1 to 8, wherein the waste material comprises two layers: a thermoplastic elastomeric polyolefin (TPO) aesthetic surface layer and a textile backing layer.

10. 8. The method of claim 7, wherein the TEC layer is a thermoplastic elastomer multilayer having a first layer that is a thermoplastic elastomeric polyolefin (TPO) surface layer having a filler content of 0 to 7% and a second layer that is a highly filled thermoplastic elastomeric polyolefin (TPO) layer having a filler content of at least 55% and not more than 85%, and at least the second layer is entangled with the fibrous layer.

11. The method according to any one of claims 1 to 10, wherein the TEC layer comprises an inert filler, preferably calcium carbonate.

12. The method according to any one of claims 1 to 11, wherein the regenerated TEC fraction is fed to a TEC extrudate, combined with normal TEC and used to produce a TEC layer.

13. 13. The method of claim 12, wherein the regenerated TEC fraction is up to 30% by weight of the total TEC extrudate.

14. The method of any one of claims 1 to 13, further comprising, preferably before step 1, a pre-separation of said two layers from any additional layers.

15. The method according to any one of claims 1 to 14, wherein the fiber fraction is incinerated or integrated into a fiber layer, a compound layer or an intermediate layer for an automotive trim part or a part for non-automotive applications.

16. 16. Use of a TEC layer comprising the recycled TEC fraction of claim 12 and / or a fiber layer, compound layer or intermediate layer comprising a recycled fiber fraction of claim 15 in an automotive trim part.

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