Multilayer composite system

Abstract

The invention relates to a multilayer composite system comprising a textile backing layer (1) and at least a first cover layer (2) based on a first polymer composition and a second cover layer (3) based on a second polymer composition. The first cover layer (2) is located completely inside the backing layer (1), and the second cover layer (3) is located above the first cover layer (2) and above the backing layer (1). The textile backing layer (1) comprises polyester textile fibers; the first and the second polymer composition each comprise one or more thermoplastic polyesters, the thermoplastic polyesters of the cover layers (2, 3) each having a lower melting point than the polyester textile fibers of the textile backing layer (1). A multilayer composite system of this type is characterized in particular in that it is completely recyclable.

Description

[0001] Description

[0002] Multi-layer composite system

[0003] The invention relates to a multi-layer composite system comprising a textile carrier layer and at least one first cover layer based on a first polymer composition and a second cover layer based on a second polymer composition, wherein the first cover layer is arranged entirely within the carrier layer and the second cover layer is arranged above the first cover layer and above the carrier layer. Furthermore, the invention relates to a load compartment cover formed from at least one such multi-layer composite system.

[0004] For decorative and simultaneously functional surfaces, for example in the interiors of properties or vehicles, a wide variety of multi-layer composite materials made of polymer material in combination with a textile carrier are known, for example based on polyolefins, polyurethanes or polyvinyl chloride. Laminated with a textile carrier, such composite materials are used extensively as covering material for seats, furniture or as window and door coverings, e.g. blinds, roller blinds or curtains. Well-known materials for textile carriers include polyester fibres. The thermoplastic polyester fibres are economically recyclable, i.e. only a fraction of the energy is required for recycling compared to new production of the material. A prerequisite for recycling, however, is the availability of pure waste.Separating the surface coating from the textile substrate, especially when the latter is coated on both sides, proves to be complex and uneconomical. Consequently, the only alternative is gasification or incineration of the structure to generate energy.

[0005] The invention is therefore based on the object of providing a pure separable multi-layer composite structure with recycling option, which is suitable for use as a decorative and functional surface in the interior or exterior of an automobile or a property.

[0006] This object is achieved by a multi-layer composite system according to claim 1. Further advantageous embodiments are disclosed in the dependent claims.

[0007] The present invention is based on a multi-layer composite system which has a textile carrier layer (1) and at least one first cover layer (2) based on a first polymer composition and a second cover layer (3) based on a second polymer composition. The first cover layer (2) is arranged completely within the carrier layer (1) and the second cover layer (3, 3a) is arranged above the first cover layer (2) and above the carrier layer (1). The multi-layer composite is characterized in that the textile carrier layer (1) comprises polyester textile fibers and the first and second polymer compositions each comprise one or more thermoplastic polyesters, wherein the thermoplastic polyesters of the cover layers (2, 3) each have a lower melting point than the polyester textile fibers of the textile carrier layer (1).Each layer of the multilayer composite system according to the invention is composed entirely of polyesters, meaning that it is fundamentally possible to melt the entire structure and reprocess it into a polyester product. Surprisingly, it has been shown that by selecting suitable coatings, the coatings can be removed from the textile carrier without significant damage to the fabric, allowing it to be recoated. According to the invention, the coating is suitable when the melting point of the materials of the multilayer polymer coating is below the melting point of the textile carrier. In this way, the polymer of the coating can be degraded while the polymer of the still-solid textile carrier remains.

[0008] The polyester textile fiber can, in principle, be any polyester fiber known to a person skilled in the art that meets the mechanical requirements of the respective application. For example, the textile can be a woven, knitted, or warp-knitted fabric. In a preferred embodiment, the polyester fiber is present as warp fiber and weft fiber in a woven fabric. This is preferably composed of a material selected from the list consisting of polylactic acid (PLA), polyadipate terephthalate (e.g., polybutyladipate terephthalate (PBAT)), polyethylene terephthalate (PET), recycled polyethylene terephthalate (PET), or mixtures thereof. Fibers made of polyadipate terephthalate (e.g., polybutyladipate terephthalate (PBAT)) are preferred, as these are also industrially degradable.

[0009] Due to certain applications that require a certain durability and stability, e.g., in automotive interior applications, PET or recycled PET is particularly preferred. Polyester fibers have a melting point of 250°C, are very tear-resistant, elastic and thermoplastic, light- and weather-resistant, and exceptionally durable. Unless otherwise stated, the melting points are determined using Dynamic Scanning Calorimetry (DSC) based on DIN EN ISO 11357-1 with a heating rate of 20°C / min. In particularly preferred embodiments, the PET fibers have a maximum tensile strength of over 2300 N / 5 cm, measured according to EN ISO 13 934-1, and / or a basis weight of over 155 g / m 2 , measured according to DIN EN 12 127.

[0010] For the purposes of the present invention, the melting point refers to the temperature at atmospheric pressure at which a polymer composition melts, i.e., changes from the solid to the liquid state. Since the melting point is only slightly dependent on pressure, changes in atmospheric pressure have virtually no effect on the melting point.

[0011] The thermoplastic polyesters of the outer layers (2, 3) can be the same or different from each other. A lower melting point can be achieved, for example, by selecting the polymer chain length. To achieve this, the thermoplastic polyesters in the outer layers would have to have a longer polymer chain length than the polyester textile fibers. Alternatively or additionally, the lower melting point can also be achieved by adding plasticizers, e.g., polyethylene glycol, triethylene glycol di-(2-ethylhexanoate), and / or isosorbide fatty acid esters.

[0012] Bio-based, biodegradable, and / or recycled polyesters can preferably be used alongside non-recycled types. Examples include PBT (polybutylene terephthalate), PET (polyethylene terephthalate), PLA (polylactide), PBAT (polybutylene adipate terephthalate), PEF (polyethylene furanoate), PTT (polytrimethylene terephthalate), PPN (polypropylene naphthalate), PPT (polypropylene terephthalate), PEN (polyethylene naphthalate), PBN (polybutylene naphthalate), PC (polycarbonate), PEC (polyester carbonate), PEF (polyethylene furanoate), PLA (polylactic acid), PHB (polyhydroxybutyrate), PAR (polyarylates), and aromatic polyesters. Copolyesters of the above-listed compounds can also be used. The melting points are preferably in the range of 60°C to 250°C. The hardness of the polyester is preferably in the range of 45 Shore A to 80 Shore D (DIN 53505).

[0013] In preferred embodiments, at least one thermoplastic polyester within a cover layer preferably has a melting point of 125°C to 250°C, preferably 125°C to 210°C. This is particularly advantageous in combination with a textile carrier formed from PET fibers. This allows the textile carrier, as a solid, to be separated from the already melted cover layers without damage and with low energy consumption. Such polyesters include, for example, polybutylene adipate terephthalate (PBAT), polylactic acid (PLA), polyhydroxybutyric acid (PHB), in particular P3HB, poly(3-hydroxybutyrate-co-3-hydroxyvalerate), and mixtures thereof.

[0014] In preferred embodiments, a polymer composition comprises at least two polyesters, wherein at least one polyester has a melting point above 125°C and at least a second polyester, in particular P4HB and polycaprolactone, has a melting point of 50°C to 125°C. By admixing the polyester with a lower melting point, the compatibility of the polymer composition with other additives is advantageously increased and the melting point of the entire polymer composition is lowered.

[0015] The total thickness from the uppermost end of the textile carrier to the uppermost end of the second cover layer is preferably between 50 μm and 1000 μm. A foamed cover layer preferably has a maximum layer thickness of 1000 μm. A compact cover layer has a maximum layer thickness of 400 μm. The choice of layer thickness can influence the material construction. For example, a compact second cover layer with a layer thickness of 50 μm may be sufficient for coloring. In this case, a foamed intermediate layer with a layer thickness of 950 μm can be selected to generate a tactilely very soft and flexible surface.

[0016] In preferred embodiments, the polymer composition of the second cover layer is colored, while the first polymer composition of the first cover layer can be compact or foamed. In embodiments in which the first cover layer is foamed, it has continuous gas- and water-vapor-permeable pores. In this embodiment, the first cover layer can form an open-pore foam structure that has breathable properties. Breathable films and multilayer composite materials comprising breathable films are known; for example, reference is made to EP 2 918 629 B1 and EP 3 808 560 A1. The breathability inherent in the films and composite materials (air or gas permeability as well as water-vapor permeability) is based on continuous pores running through the individual layers, which, however, are not the result of mechanical processing, such as needling.Rather, they are formed chemically and physically in the respective layer without mechanical processing, for example, when the layer's starting material, such as PVC or polyurethane, is spread onto a substrate and dried and gelled into a compact film under the application of heat. The first cover layer preferably has an open-pore foam structure with an air permeability of 1 to 200 l / min / dm. 2This is measured according to DIN EN ISO 9237. Alternatively or additionally, in preferred embodiments, the first polymer composition comprises a material that reflects infrared radiation (IR radiation; in particular NIR radiation). The second polymer composition preferably comprises a material that is transparent to IR radiation. As used herein, the infrared-reflective material reflects infrared light in the wavelength from 780 to 3,000 nm. The infrared-transparent (infrared-transparent) material is a material that transmits infrared light in the wavelength from 780 to 3,000 nm. A composition containing an infrared-reflective material can reflect 50% or more of the incident radiation at 780 to 3,000 nm, measured according to ASTM D1003.A composition containing the infrared-transmissive additive can transmit 1% or more, preferably 20% or more, more preferably 50% or more, most preferably 80% or more of the incident radiation at 780 to 3,000 nm, measured according to ASTM D1003. At the same time, the infrared-transmissive second cover layer can exhibit at least partial transparency to incident radiation in the visible range.

[0017] Surprisingly, it has been shown that the multi-layer composite system used in this embodiment, using IR-transparent materials in combination with IR-reflective materials, is particularly suitable for a load compartment cover in the trunk of a motor vehicle. This prevents the material or the cover system from heating up. When used inside a vehicle, this simultaneously reduces the heating of the vehicle or interior, particularly the trunk. This results in less energy being required for air conditioning the interior, particularly the trunk, thus resulting in energy savings.

[0018] For example, the IR-reflecting material can be an inorganic black pigment comprising at least one inorganic compound based on an element selected from the list consisting of iron, chromium, titanium, barium, zinc, and / or silicon. Oxides and sulfates of the aforementioned metals are preferred. In particular, titanium oxide, barium sulfate, zinc oxide, silicon oxide, and / or mixed compounds of chromium and titanium are to be used.

[0019] The material transparent to IR radiation can be, for example, a di-, tri- or multichrome dye or a pigment, in particular a perylene pigment.

[0020] The polymer compositions of the cover layers may additionally comprise further dyes and pigments to achieve a desired color setting.

[0021] The multilayer composite system can be produced by directly applying polyester dispersions or emulsions to the textile substrate. After applying a first liquid polymer composition, it is dried by heat, and the polymer powders or dispersion particles are fused. The temperatures for this process range from 80 to 240°C, preferably 100 to 200°C. Di- or multifunctional carbodiimides can also be used in the polyester dispersion or emulsion for chain extension or three-dimensional crosslinking of the polyester chains.

[0022] The multilayer composite system can alternatively be produced by indirect coating. In this process, the corresponding polyester compound is applied to a coating substrate, for example, a grain carrier (polymer or metal), embossed or unembossed release paper. A textile carrier can then be inserted into the still-liquid compound. Alternatively, a first layer can first be dried, fused / sintered, and optionally crosslinked before a second layer is applied, into which the textile carrier is inserted.

[0023] After subsequent drying and fusion, the construct can be peeled off the substrate or further coatings can be applied using polyester compound. Compared to extruded (solid) layers, a top layer can be achieved that lies within the textile carrier. The invention avoids applying the top layers using solvent-based coatings. Advantageously, the use of aqueous polymer dispersions or emulsions, in particular, allows the production of a multilayer composite system that does not contain any residual organic solvents that are hazardous to health and / or the environment.

[0024] In some embodiments, the multilayer composite system can comprise an intermediate cover layer based on a third polymer composition. This is arranged above the textile carrier layer and below the second cover layer. For foamed intermediate cover layers, the maximum layer thickness is 950 μm. For compact intermediate cover layers, the maximum layer thickness is 350 μm. In preferred embodiments, the intermediate cover layer is very thin, i.e., the layer thickness is less than 100 μm, preferably less than 50 μm.

[0025] As already mentioned, emulsions made from polyester polymer powder and polyester dispersions are preferably used to produce the top layers. The emulsions are produced by mixing and dispersing polyester powder and water with the addition of suitable dispersing agents, thickeners such as alginates, rheological aids, and flow control agents. The advantage of powder emulsion compounds is that excess unused material can be dried without forming a film, allowing it to be reused as powder for the emulsion. The powders preferably have a particle size (light scattering) of 0.01–150 pm, preferably 0.1–100 pm, and more preferably 0.1–60 pm. The average particle size is determined according to ISO 13320 using laser diffraction spectroscopy (LDS).

[0026] The dispersions are finely dispersed polyester particles in a preferably aqueous medium. The average particle sizes are preferably in the range of 0.01 to 50 μm, more preferably 0.01 to 10 μm, measured according to ISO 13320. The polyester compositions may additionally comprise a crosslinker. Carbodiimides, isocyanates, epoxides, and UV crosslinkers can be used as crosslinkers. These allow the corresponding film parameters to be adapted to the required mechanical properties of the outer layers, such as hardness or abrasion. Near-surface UV crosslinking is particularly suitable for curing the material. This also allows subsequent curing of the material.

[0027] In further embodiments of the invention, the textile carrier has a coating on both sides. In addition to the first and second cover layers, a third cover layer and a fourth cover layer are arranged on the opposite side of the textile carrier. Starting with a coating of the textile carrier on the upper side, the third and fourth cover layers are arranged on the underside. The third cover layer, analogous to the first cover layer, is arranged entirely within the carrier layer, and the fourth cover layer, analogous to the second cover layer, is arranged below the third cover layer and below the carrier layer. Analogous to the coating above the textile carrier, a second intermediate cover layer can also be arranged below the textile carrier.

[0028] The third cover layer comprises a third polymer composition, and the fourth cover layer comprises a fourth polymer composition. The third and fourth polymer compositions can, in principle, be the same or different from one another. All polymer compositions described for the first and second polymer compositions are suitable. Preferably, the third polymer composition corresponds to the first polymer composition, and the fourth polymer composition corresponds to the second polymer composition. Such a double-sided coated multilayer composite system is particularly advantageous for use as a Venetian blind or roller blind. The multilayer composite system as described above is generally suitable as a decorative and functional surface for the interior and exterior of real estate and automobiles.The multi-layer composite system preferably includes a cargo space cover, a roll-up cover system, a roller blind system, an awning system, thermal protection suits, bicycle bags, a shading system or a life raft roof.

[0029] The invention further relates to a load compartment cover comprising one of the multi-layer composite systems described above. Embodiments are particularly preferred in which the first polymer composition comprises a material that reflects infrared radiation (IR radiation), and the second polymer composition comprises a material that is transparent to IR radiation. As described above, such a load compartment cover has the advantage that it does not heat up. Accordingly, the absorbed heat is not dissipated into the environment and thus also not into the trunk of the motor vehicle. As a result, even in strong sunlight, the interior of the trunk is not heated, or only heated to a reduced degree. The load compartment cover can be rollable or designed as a solid surface.

[0030] The invention will be described in more detail below with reference to the figures.

[0031] Figure 1 shows a multilayer composite structure consisting of four layers.

[0032] Figure 2 shows a multilayer composite structure consisting of seven layers, with the textile carrier coated on both sides.

[0033] The description of the above figures is in Cartesian coordinates with a longitudinal direction X, a transverse direction Y perpendicular to the longitudinal direction X and a vertical direction Z perpendicular to both the longitudinal direction X and the transverse direction Y. The longitudinal direction X can also be referred to as depth X, the transverse direction Y as width Y and the vertical direction Z as height Z. The longitudinal direction X and the transverse direction Y together form the horizontal, X, Y, which can also be referred to as the horizontal plane X, Y. The longitudinal direction X, the transverse direction Y and the vertical direction Z can together also be referred to as spatial directions X, Y, Z or as Cartesian spatial directions X, Y, Z.

[0034] The multilayer composite structure extends essentially in the horizontal plane X, Y, with the length X and the width Y being greater than the extension in the vertical direction Z. In the context of this application, "above" is defined as the arrangement of a layer in a positive Z coordinate relative to another layer. In the context of this application, "below" is defined as the arrangement of a layer in a negative Z coordinate relative to another layer.

[0035] Figure 1 shows an exemplary multi-layer composite system according to an embodiment of the present invention. The textile carrier (1) is formed from a PET fiber fabric. The first cover layer (2) is arranged completely within the textile carrier (1), wherein the first cover layer (2) and the textile carrier (1) form a common upper edge. The polymer composition of the first cover layer (2) comprises 53 wt. % of a PBAT polymer and 2 wt. % of an IR-reflecting pigment. Adjacent to the textile carrier (1) and the first cover layer (2) is an intermediate cover layer (4). This has the same polymer composition as the first cover layer (2). The thickness of the intermediate cover layer (4) is 50 μm. A second cover layer (3) is arranged directly adjacent to the upper interface of the intermediate cover layer (4). The polymer composition of the second cover layer (3) comprises 44 wt. % PET as base polymer and 2 wt.-% of an IR-transparent dye.

[0036] Figure 2 shows a further exemplary multi-layer composite system according to an embodiment of the present invention. In this embodiment, the textile carrier (1) has a coating on both sides. The first cover layer (2a), the intermediate cover layer (4a), and the second cover layer (3a) correspond to the cover layers (2, 3, 4) from the embodiment in Figure 1. In addition, a third cover layer (2b) is arranged completely within the textile carrier (1) such that the third cover layer (2b) and the lower surface of the textile carrier (1) share a common lower surface. A lower intermediate cover layer (4b) is arranged directly adjacent. A fourth cover layer (3b) is arranged below this. The polymer composition of the lower cover layers (2b, 3b, 4b) corresponds to the analogous upper cover layers (2a, 3a, 4a).

[0037] List of reference symbols (part of the description)

[0038] 1 textile carrier layer

[0039] 2, 2a first cover layer 2b third cover layer

[0040] 3, 3a second cover layer

[0041] 3b fourth top layer

[0042] 4, 4a upper intermediate deck layer

[0043] 4b lower intermediate deck layer

Claims

Patent claims 1. Multi-layer composite system comprising a textile carrier layer (1) and at least one first cover layer (2) based on a first polymer composition and a second cover layer (3) based on a second polymer composition, wherein the first cover layer (2) is arranged completely within the carrier layer (1) and the second cover layer (3, 3a) is arranged above the first cover layer (2) and above the carrier layer (1), characterized in that the textile carrier layer (1) comprises polyester textile fibers and the first and the second Polymer composition each comprise one or more thermoplastic polyesters, wherein the thermoplastic polyesters of the cover layers (2, 3) each have a lower melting point than the polyester textile fibers of the textile carrier layer (1).

2. Multi-layer composite system according to claim 1, wherein the polyester textile fiber is a woven fiber selected from the list consisting of polylactic acid, polyethylene terephthalate (PET), recycled polyethylene terephthalate (PET) or mixtures thereof.

3. Multi-layer composite system according to one of claims 1 or 2, wherein at least one of the thermoplastic polyesters within a cover layer (2, 3) has a melting point of 125°C to 250°C.

4. Multi-layer composite system according to one of the preceding claims, wherein the thermoplastic polyesters of the cover layers (2, 3) are selected from the list consisting of polybutylene terephthalate, polyethylene terephthalate, polylactide, polybutylene adipate terephthalate, polyhydroxyacetic acid, poly-E-caprolactone, polypropylene terephthalate, polyethylene furanoate, and mixtures thereof.

5. Multi-layer composite system according to one of the preceding claims, additionally comprising an intermediate cover layer (4) based on a third polymer composition, which is arranged above the textile carrier layer (1) and is arranged below the second cover layer (3), wherein the intermediate cover layer (4) has a thickness of at least 0.01 mm and at most 1 mm and wherein the third polymer composition corresponds substantially to the first polymer composition.

6. Multi-layer composite system according to one of the preceding claims, wherein the total thickness from the lowest end of the first cover layer (2) to the uppermost end of the second cover layer (3) is from 50 pm to 1000 pm.

7. Multi-layer composite system according to one of the preceding claims, wherein at least one cover layer (2, 3, 4) has an open-pore foam structure with an air permeability of 1 to 200 l / min / dm 2 has.

8. Multilayer composite system according to one of the preceding claims, wherein the first polymer composition comprises a material reflecting IR radiation and the second polymer composition comprises a material transparent to IR radiation.

9. Multilayer composite system according to claim 8, wherein the IR radiation-reflecting material is an inorganic black pigment comprising at least one inorganic compound based on an element selected from the list consisting of iron, chromium, titanium, barium, zinc and / or silicon.

10. Multilayer composite system according to one of claims 8 or 9, wherein the material transparent to IR radiation is a di-, tri- or multichrome dye or a pigment, in particular a perylene pigment.

11. Multi-layer composite system according to one of the preceding claims, comprising a third cover layer (2b) and a fourth cover layer (3b), wherein the third cover layer (2b) is arranged completely within the carrier layer (1) and the fourth cover layer (3b) is arranged below the third cover layer (2b) and below the carrier layer (1).

12. Load compartment cover with a multi-layer composite system according to one of claims 1 to 11.

13. Vehicle with a load compartment cover according to claim 12.

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