ARTIFICIAL LEATHER AND A METHOD FOR SEPARATING THE TEXTILE SUPPORT OF THE SAME

Description

[0001] The invention relates to an artificial leather which comprises a textile carrier and a coating composite comprising several layers and applied to the textile carrier and based on plastic masses, wherein the layer applied directly to the textile carrier acts as an adhesion layer and firmly bonds the coating composite to the textile carrier.

[0002] Artificial leather of the type mentioned above is widely known and is widely used, for example, as a covering material for seating furniture and automotive interiors. A textile substrate is typically provided facing away from the visible surface, which can be made from natural and / or synthetic fibers as a woven, non-crimp, knitted, or nonwoven fabric. Several discrete layers of a coating composite based on plastic compounds, usually based on polyvinyl chloride (PVC), polyolefins, or polyurethanes, are applied to the textile substrate.

[0003] From JP S51 88602 A3 and CN 105 178 049 A, artificial leathers of the aforementioned type are known, for example, in which the adhesion layer contains metal particles or carbon particles in order to increase the temperature or weather resistance of the artificial leather.

[0004] Since the textile carrier typically has a chemical composition that differs from that of the coating composite, such synthetic leather cannot be recycled in its pure form at the end of its useful life. Instead, the synthetic leather, which is a composite system consisting of the textile carrier and the coating composite, can currently only be shredded and then, in a further step, pressed into inferior recycled products to generate a usable, low-cost alternative. Only in the few exceptional cases where the coating composite and the textile carrier come from the same material group, for example, polyurethane, can pure recycling be carried out. This appears to be in need of improvement.

[0005] The object of the invention is to propose an artificial leather which enables easy and complete separation of the textile carrier from the coating composite applied thereto after the service life has been exceeded, in order to enable a pure processing of the components of the artificial leather, ie textile carrier on the one hand and coating composite on the other.

[0006] In this respect, it is also an object of the invention to propose a method for separating the textile carrier of such an artificial leather from the coating composite.

[0007] To achieve the stated object, the invention proposes the design of an artificial leather having the features of patent claim 1.

[0008] Advantageous embodiments and further developments of the invention are the subject of the dependent claims.

[0009] The invention proposes that artificial leather be modified in such a way that the plastic mass of the adhesion layer contains energy-absorbing additives which are intended to heat the adhesion layer by means of the energy-absorbing additives under the influence of suitable electromagnetic radiation and / or electron radiation in such a way that the strong adhesive bond to the textile carrier is removed, so that the textile carrier can be separated from the coating composite.

[0010] A typical synthetic leather structure typically consists of a multi-layer composite with up to eleven layers. These are, for example, lacquer layers based on polyurethane, acrylates, PVC, or fluorine on the visible surface. These lacquer layers are very thin compared to the other layers of the coating composite and weigh very little in direct comparison. Other layers, usually arranged beneath the lacquer layers, are the so-called top layer, which determines the color and functional properties, such as abrasion and environmental properties; a volume layer, which adjoins the textile carrier and can be foamed, for example; and finally the adhesion layer, which firmly bonds the aforementioned layers of the coating composite to the textile carrier and is therefore applied to the surface of the textile carrier.Within the scope of the invention, it was found that a suitable proportion of energy-absorbing additives can be introduced into this adhesion layer, which, according to the invention, do not or do not significantly impair the adhesion behavior of the adhesion layer to the textile carrier and the oppositely adjacent further layer of the coating composite.

[0011] However, by exposure to suitable electromagnetic radiation and / or electron beams or a corresponding energy source, these energy-absorbing additives can be heated within the plastic mass of the adhesion layer serving as the matrix, whereby the temperature of the adhesion layer in the artificial leather is selectively increased to such an extent that the adhesion to the textile carrier and / or the adjacent further layer of the coating composite is lost or eliminated at least to such an extent that the coating composite can be separated from the textile carrier and these separated components can then be subjected to appropriate sorted further processing, for example for the purpose of reprocessing.

[0012] According to the invention, the heating of the adhesion layer using radiation can be carried out significantly faster than heat dissipation into the adjacent layers through thermodynamic processes. This results in the desired selective separation of the textile carrier from the adhesion layer.

[0013] Since the heating of the adhesion layer caused by electromagnetic radiation and / or electron beams is limited to this adhesion layer, the remaining layers of the coating composite and the textile carrier remain largely unaffected thermally. Only a thermal weakening of the adhesion layer occurs.

[0014] According to a proposal of the invention, the energy-absorbing additives are based on metal particles, ionic compounds such as salts, semiconductor compounds, e.g. based on silicon or silicon carbide, graphite particles, carbon nanotubes, soot particles, conductive polymers such as polyaniline and / or ionic liquids.

[0015] In the simplest case, the adhesion layer modified according to the invention is a so-called laminating film, for example based on polyurethane, which is pigmented with a suitable amount of carbon black particles.

[0016] According to one proposal of the invention, the adhesion layer can be irradiated using any suitable electromagnetic radiation to heat the additives. In the case of electromagnetic radiation, induction, microwave, or infrared radiation are particularly suitable. Furthermore, electron beams can also be used to heat the additives, both individually and in combination.

[0017] In particular, irradiation of the synthetic leather with infrared radiation at a wavelength of 800 to 2000 nm is considered suitable, using an adhesion layer containing appropriate infrared-absorbing additives. The same applies to the use of carbon nanotubes as energy-absorbing additives, which can also be stimulated by infrared radiation.

[0018] When using carbon nanotubes, metal particles, and graphite as energy-absorbing additives, microwave radiation can also be used to introduce the desired energy into the material and heat the adhesion layer.

[0019] Induction beams can be used for magnetic and magnetizable additives, such as ferromagnetic additives and additives that are induction-sensitive. This also applies to the use of aluminum particles as energy-absorbing additives.

[0020] The invention proposes that the energy-absorbing additives be incorporated into the plastic composition of the adhesion layer, which is present, for example, as a lamination or adhesive coating within the synthetic leather according to the invention, at a concentration of 0.001% to 25% (phr). Preferably, the concentration of the additives within the adhesion layer should be approximately 0.01 to 10% (phr). The appropriate concentrations, as well as radiation intensities and durations, can be easily determined by a person skilled in the art based on the achievable separation tendency between the textile carrier and the coating composite.

[0021] The artificial leather according to the invention can in particular have an adhesion layer based on polyurethane, which can also be partially cross-linked, so that the adhesion layer still has thermoplastic properties.

[0022] In addition to such adhesion layers based on polyurethane, adhesive coats based on acrylates, polyvinyl chloride, copolymers based on or in mixtures with vinyl alcohols, vinyl acetates, which are present in artificial leather structures and act as adhesion layers, can also be used and processed.

[0023] A method according to the invention for separating the textile carrier of a previously described artificial leather after reaching or exceeding its useful life provides for the provided artificial leather to be irradiated with suitable electromagnetic radiation and / or electron beams in such a way that the adhesive layer is heated to a temperature at which the strong bond between the adhesive layer and the textile carrier is broken. The coating composite can then be detached from the textile carrier and subjected to a separate processing step, for example, to enable sorting by type in selected recycling pathways.

[0024] According to the invention, after the use of the artificial leather and during the recycling process, the composite forming the artificial leather, consisting of textile carrier and coating composite, is incubated with a suitable energy source in order to heat the adhesion layer and to reduce the adhesion to the other layers of the coating composite and the textile carrier to such an extent that a separation of the textile carrier from the coating composite is made possible.

[0025] Electromagnetic radiation can be used, in particular, induction, infrared, and / or microwave radiation. When using infrared radiation, a wavelength of 800 to 2000 nm is considered particularly suitable.

[0026] The synthetic leather according to the invention and the process make it possible, for example, to irradiate a seat cover material made of the synthetic leather according to the invention with the appropriate electromagnetic radiation and / or electron beams directly in the installed state, so that the upper layers formed from the coating composite can be removed from the textile carrier. Alternatively, for example, the feeding of sections or webs of the synthetic leather to be recycled to a corresponding irradiation device can also be provided.

[0027] The separation speed of the textile carrier from the coating composite can be adjusted according to the prevailing energy absorption or the achievable energy input.

[0028] The invention also makes it possible to separate multi-layer composite systems with textile carriers separately, i.e. without components, and to sort them further or recycle them.

[0029] Since, according to the invention, the heating of the adhesion layer by irradiation occurs significantly faster than the heat dissipation by thermodynamic processes into adjacent layers, a selective detachment occurs between the textile carrier and the heated adhesion layer.

Claims

1. Synthetic leather, which comprises a textile carrier and a coating composite which comprises two or more layers, is applied to the textile carrier and is based on plastics compounds, wherein the layer applied directly to the textile carrier as an adhesion layer connects the coating composite firmly to the textile carrier, characterized in that the plastics compound of the adhesion layer contains energy-absorbing additives which are intended to heat the adhesion layer by exposure to electromagnetic radiation and / or electron radiation in such a way that the firm connection to the textile carrier is reversed.

2. Synthetic leather according to Claim 1, characterized in that the energy-absorbing additives are based on metal particles, semiconductor compounds, graphite particles, carbon nanotubes, conductive polymers, carbon black particles and / or ionic liquids.

3. Synthetic leather according to Claim 1 or 2, characterized in that the adhesion layer is heatable by means of induction, microwave or infrared radiation.

4. Synthetic leather according to Claim 3, characterized in that the adhesion layer is heatable by means of electromagnetic radiation of a wavelength of 800 to 2000 nm.

5. Synthetic leather according to any of Claims 1 to 4, characterized in that the additives are incorporated in the plastics compound of the adhesion layer in a concentration of 0.001% to 25% (phr).

6. Synthetic leather according to Claim 5, characterized in that the additives are incorporated in the plastics compound of the adhesion layer in a concentration of 0.01% to 10% (phr).

7. Synthetic leather according to any of Claims 1 to 6, characterized in that the adhesion layer is formed on the basis of polyurethane.

8. Synthetic leather according to any of Claims 1 to 6, characterized in that the adhesion layer is formed as a tie coat based on acrylates, polyvinyl chloride and / or copolymers based on or in a blend of vinyl alcohols or vinyl acetates.

9. Synthetic leather according to any of Claims 1 to 8, characterized in that the adhesion layer is at least partially crosslinked.

10. Method for separating the textile carrier of a synthetic leather according to any of the preceding claims, comprising providing the synthetic leather and irradiating the synthetic leather with electromagnetic radiation and / or electron radiation, such that the adhesion layer is heated to a temperature, so that the firm connection between the adhesion layer and the textile carrier is reversed, and then detaching the coating composite from the textile carrier.

11. Method according to Claim 10, characterized in that electromagnetic radiation used comprises induction, infrared and / or microwave radiation.

12. Method according to Claim 10 or 11, characterized in that the electromagnetic radiation has a wavelength of 800 to 2000 nm.