Breathable multi-layer composite

Abstract

The invention relates to a sustainable and breathable multi-layer composite, in particular artificial leather, comprising at least one textile substrate and a functional layer, wherein the multi-layer composite has an air permeability of 0.1-200 Idm-2min-1, determined according to DIN EN ISO 9237-1995, and a water vapor permeability of 0.1-200 mgcm-2h-1, determined according to DIN EN ISO 14268.2-2013 method C, and wherein the breathable multi-layer composite is made of at least 60 wt.% bio-based and / or recycled raw materials, based on the total weight of the multi-layer composite.

Description

[0001] Description

[0002] Breathable multi-layer composite

[0003] The invention relates to a breathable multilayer composite, in particular an artificial leather, comprising at least one textile substrate and a functional layer.

[0004] Breathable synthetic leathers are known, for example, reference is made to EP 2 918 629 B1 or EP 3 795 618 A1. These synthetic leathers are used, among other things, as shoe uppers, in wall and ceiling coverings, or as seat covers, especially for vehicle interiors or (seating) applications in commercial settings such as stadiums, cinemas, theaters, restaurants, fast-food chains, cafes, cruise ships, and hotels. The breathability inherent in the films and composite materials is due to the continuous pores running through the individual layers. These pores are not the result of mechanical processing, such as needling, but are formed chemically within the respective layer without mechanical treatment. This occurs, for example, when the base material of the layer, such as PVC or polyurethane, is coated onto a substrate and dried and gelled into a compact film under the application of heat.The resulting pores and the breathability caused by these pores, which the invention understands to mean both air or gas permeability and water vapor permeability, are not directly visible or apparent from the outside by viewing with the human eye.

[0005] Plastic materials, especially synthetic leather, typically contain a number of additives necessary to give the material specific properties. The additives commonly used are generally based on conventional chemical products or primary raw materials. The thermoplastic polymer itself makes up the largest proportion, at up to 90% by weight. However, there is a steadily growing interest, particularly in light of legal requirements and guidelines, in working towards replacing conventional additives with more sustainable products. This aims, in particular, to reduce the ecological and CO2 footprint of the final product, e.g., made of plastic.

[0006] The task is therefore to find a breathable multi-layer composite, especially for use as synthetic leather, which contains a high proportion of bio-based and recycled raw materials and retains the desired properties, for example to be used as synthetic leather indoors and outdoors.

[0007] This problem was solved by the breathable multilayer composite according to claim 1.

[0008] According to the invention, the breathable multilayer composite comprises at least one textile substrate and one functional layer. The multilayer composite is breathable because it has an air permeability of 0.1 to 200 ldnr. 2 min' 1 , determined according to DIN EN ISO 9237-1995, and a water vapor permeability of 0.1 to 200 mgcrrr 2 h' 1The breathable multilayer composite according to the invention is based on at least 60 wt.% bio-based and / or recycled raw materials, as defined in DIN EN ISO 14268.2-2013, Method C. The wt.% refers to the total weight of the multilayer composite.

[0009] A layer, as defined in the invention, is a mass of material spread over a surface. A layer consists of a material composition, e.g., a polymer composition, a textile layer, a varnish in a dimensionally stable state, etc.

[0010] A layer, as defined in the invention, is a mass of a material spread over a surface, e.g., a carrier layer, top layer, or functional layer. A layer can be formed from one or more layers, which may be arranged above or below one another. A layer formed from a single layer may also be referred to as a layer, and vice versa. Multiple layers can, in principle, be arranged above or below one another. Multilayered coatings are preferably formed from layers of the same material composition. In this context, material compositions are considered identical if they do not differ with respect to their chemical components. The quantity of the chemical components may vary slightly. For example, a top layer may comprise 2, 3, 5, or 7 layers of a coating composition.

[0011] For the purposes of this invention, a sustainable material is defined as one that is based to some extent on natural substances or reused materials (e.g., recycled raw materials or recycled products) or is itself recyclable (e.g., through biodegradability or recycling). A natural substance, as defined in this invention, is an inorganic substance occurring in nature, such as CO2, salt, or metal (oxides), or an organic substance occurring naturally and that is naturally renewable (e.g., sugar cane, fungi, mycelium, bacterial components, hemp, cotton, etc.). Such natural substances serve as raw materials for a bio-based material. A sustainable material, such as a bio-based material, can additionally be biodegradable and / or harmless or of low hazard (e.g., as defined by REACH or Proposition 65) to humans and the environment, so that it can be returned to the natural ecosystem.Reused fabrics can also include bio-based materials. For example, reused fabrics can be recycled polymers or reused waste materials, such as textiles recovered from discarded products.

[0012] The matrix-forming polymers, in combination with a filler and / or plasticizer, constitute the predominant part of the polymer composition (over 50 wt.% based on the total mass of the functional layer) suitable for forming a functional layer according to the invention. Therefore, replacing these components with the more sustainable alternatives is particularly efficient in improving the sustainability of the overall product, i.e., the multilayer composite. In preferred embodiments, the functional layer of the breathable multilayer composite comprises a polymer that is at least partially bio-based or recycled. Furthermore, it may also contain other polymers that do not meet the definition of a sustainable material. At least one preferably at least partially bio-based or recycled polymer is the matrix-forming polymer of the polymer composition.The functional layer of a multilayer composite according to the invention is formed from the polymer composition by forming the polymer composition as at least one layer of the functional layer. The polymer compositions within a layer can be different, or all layers of the layer can be formed from the same polymer composition. Suitable methods for forming a layer from several layers, including forming a layer from the polymer composition, are known to persons skilled in the art and do not require further description within the scope of this invention.

[0013] The polymer composition of at least one layer of the functional layer can contain a polymer or a combination of two or more polymers as a matrix. Suitable polymers for forming a layer have a molecular weight of at least 10,000 g / mol, preferably more than 15,000 g / mol.

[0014] Preferably, at least one polymer of the functional layer is selected from the group consisting of polyvinyl chloride (PVC), thermoplastic elastomers (TPE), thermoplastic polyurethane (TPU), thermoplastic polyolefin (TPO), polylactide, polyesters, in particular polyhydroxyalkanoates, e.g., polyhydroxybutyric acid, polyvinyl acetals, e.g., polyvinyl butyral (PVB), or a combination thereof. Examples of suitable thermoplastic elastomers are urethane-based thermoplastic elastomers, thermoplastic copolyester elastomers (TPE), thermoplastic styrene block copolymers (TPS), and olefin-based thermoplastic elastomers, e.g.,

[0015] Polypropylene / ethylene propylene diene monomer rubber (PP / EPDM). Polyvinyl chloride and / or polyurethane are particularly preferred as the polymer matrix. In a preferred embodiment, the functional layer comprises at least two different matrix-forming polymers. Preferably, this is a mixture of at least PVC and TPU.

[0016] Furthermore, it is preferred that the functional layer is formed from at least two layers, in particular from 3 to 4 layers, of a polymer composition.

[0017] In preferred embodiments, the functional layer comprises one or more at least partially bio-based or recycled polymers. It is even more preferred that an at least partially bio-based or recycled polymer is produced from at least 30 wt.% biomass, based on the weight of the respective crude polymer.

[0018] In embodiments where the functional layer comprises at least one PVC, the entire PVC content of the functional layer can be at least a partially bio-based or recycled polymer. In particular, the PVC can be a PVC produced from renewable ethylene derived from biomass. An example of a suitable PVC is GreenVin® from Vinnolit.

[0019] In embodiments where the functional layer comprises at least one TPU, the entire TPU component of the functional layer can be at least partially bio-based or recycled polymer. In particular, the TPU can be a TPU made from at least 40% by weight of biomass based on the total mass of the crude polymer, or a TPU produced using CO2 (e.g., ESTANE®ECO TPU). Other examples of suitable TPUs include Elastollan® N from BASF (a maize-based biopolymer with a bio-based content of 45 to 60% by weight based on the total weight of the raw materials), and Desmopan® from Covestro, including Desmopan® CQ RC (based on recycled products) and Desmopan® CQ EC (based on starch or maize).

[0020] The proportion of matrix-forming polymers in the polymer composition of the functional layer can vary widely, for example, from 20 to 80 wt.%, preferably 20 to 60 wt.%, based on the total weight of the polymer composition. In preferred embodiments, the entire proportion of matrix-forming polymers of a functional layer consists of, or is a mixture of, at least partially bio-based or recycled polymers as described above.

[0021] In some embodiments, the breathable multilayer composite includes a filler that is incorporated into the polymer composition of the functional layer. The functional layer of the breathable multilayer composite preferably comprises a bio-based and biodegradable filler. In particularly preferred embodiments, the bio-based and biodegradable filler is coffee grounds powder and / or a filler based on native cellulose.

[0022] Interestingly, it has been found that coffee grounds act as an antibacterial component in synthetic leather, particularly in highly porous, breathable systems. The coffee grounds also support pore formation, which gives the multilayer composite or functional layer containing the coffee powder its breathable properties. The rough surface of the coffee ground particles creates nucleation points in the polymer matrix. This results in a finer network of pores, which in turn influences breathability.

[0023] The use of coffee grounds as a filler also proves to be particularly environmentally friendly, as coffee grounds contain CO2 bound from the air. If the coffee grounds are composted, this CO2 is released back into the environment. If the coffee grounds are prevented from degrading / breaking down, the CO2 absorbed from the air remains in the product. In this way, the coffee grounds also act as a CO2 sink.

[0024] Essentially, coffee grounds are the product of extracted, ground coffee beans and have a large surface area. Depending on the extraction method—whether in a home coffee machine or industrially with up to 60 extraction processes—the corresponding oils and volatile components are present in varying proportions. The majority of coffee grounds preferably consist of approximately 40 to 60% by weight of cellulose and / or hemicellulose, as well as up to 30% by weight of lignin, fatty acids, and / or proteins, based on the total weight of the original, dry coffee grounds.

[0025] Coffee grounds, obtained as a waste product, can be used as is. However, prior processing may be advantageous, for example, to obtain a more uniform starting product with regard to the desired particle size and moisture content. Suitable methods for processing coffee grounds for use as a filler in plastic materials are known to competent persons, for example, from RSC Adv., 2021, 11, 2682-2692. When using coffee grounds for coloring the plastic material, it is usually advantageous to use fractions with a narrow particle size distribution. Coffee grounds can, for example, be present in widely varying degrees of fineness and particle size and have varying moisture content. Processing to provide coffee grounds with desired parameters and / or for standardization can be carried out, for example, by...This includes drying to the desired moisture content and / or milling and sieving processes, and, if necessary, separation into suitable size fractions. Milling and, if necessary, classification are usually carried out after drying.

[0026] The water content of the coffee grounds powder can, for example, range from 0 to 20 wt.%, based on the total weight of the coffee grounds powder. In some embodiments (e.g., compact functional layer), an excessively high water content can interfere with the production of the plastic material, as bubble formation or uncontrolled evaporation of water can cause defects in the film and thus limit the mechanical properties of the resulting layer. In this respect, it is preferred if the water content of the coffee grounds powder is up to 5 wt.%, preferably up to 2 wt.%, based on the total weight of the coffee grounds powder. The coffee oils, released during the roasting process, are present in high concentrations as carboxylic acids. The proportion of coffee oils is preferably in the range of 0.1–30 wt.%, particularly 7 to 15 wt.%, based on the total weight of the original, dry coffee grounds.

[0027] In preferred embodiments, the mean diameter of the coffee grounds particles is less than or equal to 500 pm, more preferably less than or equal to 250 pm, and more preferably less than or equal to 100 pm. The mean diameter of the coffee grounds particles is preferably greater than or equal to 20 pm, more preferably greater than or equal to 50 pm, and most preferably greater than or equal to 80 pm. The particle size of the coffee grounds particles refers to the mean particle size (d90 value), based on the volumetric diameter or the numerical diameter, and can be determined, for example, by light scattering or laser diffraction. Monomodal and multimodal particle size distributions are possible. Within the scope of this disclosure, the particle size is determined according to ISO 13320:2020.

[0028] Depending on the particle size, the functional layer can be structured in such a way that the coffee grounds appear as a solid color (smaller particle sizes) or as a speckled pattern (larger particle sizes). For example, coffee grounds with a particle size larger than 100 pm are visible to the naked eye in the functional layer. This can create a characteristic optical effect.

[0029] In preferred embodiments, the total amount of coffee ground particles, based on the dry weight, in the functional layer is 0.01 to 50 wt.%, preferably 0.1 to 30 wt.%, most preferably 2 to 20 wt.%, in each case based on the total weight of the polymer composition. If the polymer composition is applied to the substrate by a coating process, such as with a doctor blade or a roll coater, the coffee ground particle content, based on the dry weight of the coffee grounds, can be, for example, in the range of 0.01 to 20 wt.%, preferably 0.1 to 12 wt.%, and particularly preferably 2 to 12 wt.%, based on the total weight of the functional layer. If the polymer material is applied by extrusion or calendering, the coffee ground particle content, based on the dry weight of the coffee grounds, can be, for example, in the range of 0.01 to 70 wt.%, preferably 2 to 50 wt.%, and particularly preferably 10 to 50 wt.%.-%, based on the total weight of the functional layer.

[0030] In advantageous embodiments, the solid fillers are pre-dispersed in a plasticizer and then added to the mixture for further processing. This results in the partially bio-based mixtures having a lower or no susceptibility to mold growth and, consequently, a significantly longer shelf life.

[0031] Alternatively or additionally, the functional layer of the breathable multilayer composite can contain a cellulose-based filler. Cellulose is a linear homopolymer of d-glucopyranose monomer units. The monomers are linked by β-1,4-glycosidic bonds, and every second monomer unit is axially rotated by 180°. The degree of polymerization of cellulose depends on its source and can vary from 300–1700 for wood pulp to 10,000 for cotton and flax. Native cellulose is preferably used. Native cellulose (also called lignocellulose), a naturally occurring, unprocessed substance, typically comprises other components besides cellulose, including a certain amount of lignin and optionally hemicellulose. Lignocellulose forms the cell wall of woody plants and serves as their structural framework.For the purposes of the invention, for example, solids based on native cellulose, i.e. containing at least cellulose or lignin, are to be regarded as suitable fillers.

[0032] Olive kernel flour is particularly favored for use as a filler. It is a commercially available (e.g., Olea Europaea Seed Powder from Schillig Ltd.) processed natural substance. Pure, clean olive kernel granules / olive kernel flour are the result of a complex processing of waste from olive oil production. To obtain olive oil, the olive is always pressed whole, including the pit. The defatted residue (olive pomace) is then processed in its wet state using specialized machinery. In a centrifugation step, the crushed olive kernels are separated from pulp and skin remnants and then mechanically cleaned, dried, and sieved. The result is light beige, virtually odorless granules free of dust and fruit residue. Micronization into high-quality granules and powders can then be carried out.Compared to other natural granules made from wood, corn, cellulose, silica, pumice and others, the use of olive kernel flour results in additional health-promoting effects (e.g. anti-inflammatory antioxidants).

[0033] Furthermore, olive kernel flour proved to be non-allergenic, vegan, halal and kosher.

[0034] The stability and hardness of the particles (also known as olive kernel flour particles) ensure improved efficiency. Unlike many other natural materials, these particles hardly break or disintegrate. Therefore, micronization into a wide range of clearly defined particle sizes is possible. Furthermore, the use of olive kernel flour in polymer composites is advantageous because it not only increases the bio-based content of the composite, but also because the reactive properties and the powder's function as a binder and structure-enhancing agent demonstrably improve the composite's resistance, tensile and flexural strength, and lifespan.

[0035] In preferred embodiments, the mean diameter of the olive kernel flour particles is from 0.1 to 300 pm, preferably from 0.1 to 250 pm, and more preferably from 0.1 to 100 pm, as determined according to ISO 13320:2020. The particle size refers to the mean particle size (d90 value), based on the volumetric diameter or the numerical diameter. Depending on the application, different particle sizes with different particle size distributions are advantageous.

[0036] The functional layer can be opaque, translucent, or transparent. Here, "transparent" or "see-through" refers to a material that allows light waves to pass through (transmission), so that an object behind the material can be seen relatively clearly. The degree of transparency depends on the wavelength of the light; at wavelengths below this, the transparent material is tinted by absorptive particles. The higher the concentration of these particles, the more opaque the material becomes. Materials that are no longer transparent but still allow light to pass through are described as "translucent" or "see-through." Objects cannot be clearly identified behind such materials (e.g., frosted glass, human skin). If the object behind the material can no longer be seen, the material is described as "opaque," "non-transparent," "light-blocking," or "opaque."The inverse property of translucency is opacity (light impermeability). A material with high translucency has low opacity, and vice versa. In a translucent or transparent functional layer, the proportion of filler powder is relatively low.

[0037] The polymer material may also contain one or more other additives that are common in the field. Examples of suitable additives include dyes, pigments, matting agents, quantum dots, plasticizers, fillers, leveling agents, defoamers, lubricants, rheology aids, thickeners, wetting agents, crosslinkers, light stabilizers, surface modifiers, stabilizers, reinforcing agents (such as fibers), flame retardants, blowing agents (chemical or physical), surfactants, and / or biocides. A person skilled in the art can select suitable additives depending on the intended use.

[0038] In a preferred embodiment, the polymer material comprises at least one plasticizer. The plasticizer can vary depending on the matrix-forming polymer used and the intended application. Suitable plasticizers are commercially available and known to those competent in the field. Examples of suitable plasticizers include phthalic acid esters, aliphatic dicarboxylic acid esters, epoxidized oils, trimellitates, polyesters (with a molecular weight of less than 7000 g / mol), succinate plasticizers, castor-based plasticizers, phosphoric acid esters, lecithin-based plasticizers, fatty acid esters, terephthalic acid esters, and mixtures thereof. For example, sulfonic acid esters such as Mesamoll, phthalate-free ((C10-C21) phenylalkanesulfonic acid esters, CAS 91082-17-6), or Pevalen (2,2-bis[[(1-oxopentyl)oxy]methyl]propane-1,3-diyl divalerate, CAS 15834-04-5) are commercially available.

[0039] In particularly preferred embodiments, the functional layer comprises a bio-based or recycled plasticizer, either as an alternative or supplement to conventional plasticizers. Unlike matrix-forming polymers, plasticizing polymers have a molecular weight of less than 7,000 g / mol. The plasticizer advantageously acts as a processing aid within the polymer composition, for example, by facilitating the rapid distribution of nonpolar components (e.g., coffee oils, pigments, dyes, etc.). This results in faster migration of the dyes into the polymer phase.

[0040] The sustainable (e.g., bio-based) plasticizer is preferably selected from the group consisting of adipic acid esters, epoxidized soybean oil (synthetic and / or natural), oxidized castor oil, esterified succinates, and mixtures thereof. Suitable plasticizers are certified organic or produced according to the biomass balance method. Examples of suitable commercially available sustainable plasticizers include, for example, the polymer plasticizers Palamoll 652 from BASF, GLOBINEX W-1810-BIO from DIC, Grindstead Soft & Safe from Danisco AS (castor-based), and Epoxdol D65 from FACI SpA (epoxidized soybean oil).

[0041] According to the invention, the substrate of the breathable multilayer composite is a textile. For the purposes of this invention, "textile" refers to textile fabrics (also textile fabric products). These include structures made of fibers of chemical (e.g., acetate, polyester, polyacrylic), animal (e.g., wool, silk), plant (e.g., cotton, flax, coconut), or mineral (e.g., rock wool, glass fibers, and basalt fibers) origin. "Textiles" encompass both textile fibers and raw materials, semi-finished products, or finished products of the textile industry.

[0042] Preferably, the textile substrate of the breathable multilayer composite is based on naturally occurring polymer fibers and / or recycled plastic fibers. Preferably, the textile is at least partially based on recycled thermoplastic polymers or on bio-based polymers. Particularly suitable recycled thermoplastic polymers are polyester, TPU, PP, and / or PE, and mixtures thereof. Particularly suitable bio-based polymers are cellulose, polyester, cotton, and mixtures thereof. A preferred substrate is a textile based on recycled thermoplastic polymers, in particular polyester, TPU, PP, and / or PE; a recycled cotton textile; a cellulose-based textile; a textile based on bio-based polymers, in particular a bio-based polyester and / or cellulose, and mixtures thereof. Fibers made of recycled or at least partially bio-based polyester and / or cotton are especially preferred as substrate materials.

[0043] In another aspect of the invention, the multilayer composite can exhibit high flame resistance without the need for flame retardants based on antimony, phosphorus, or nitrogen compounds. Suitable flame retardants are selected in particular from the group consisting of organic phosphorus compounds such as organic phosphinate, aryl phosphate esters or phosphorus-containing polyols, ammonium phosphate or polyphosphate, melamine cyanurate, melamine phosphate, melamine, melamine polyphosphate, red phosphorus, aluminum diethyl phosphinate, aluminum trihydroxide, magnesium hydroxide, zinc stannate, expandable graphite, zinc borate, and mixtures thereof. Preferably, the flame retardant has a low tendency to migrate within the functional layer. For example, organic phosphorus flame retardants can migrate to the surface and form a coating, thereby altering the material properties accordingly, e.g.,Odor-intensive UV or oxidation products, or reduced flame-retardant properties when the substances are removed, are problematic. Naturally occurring mineral flame-retardant additives, such as aluminum hydroxides, magnesium hydroxides, and boric acids, and / or bio-based flame-retardant additives, such as reaction products of cellulose and sugar alcohol-based compounds with phosphorus derivatives, are particularly preferred. Suitable commercially available flame-retardant additives include, for example, lignin-based compounds from Devan. According to the invention, the breathable multilayer composite is based on at least 60% by weight, preferably 75%, and most preferably 90% bio-based and / or recycled raw materials. Higher proportions of bio-based and / or recycled raw materials can be achieved, for example, by replacing more conventional components of the polymer composition with more sustainable components, i.e., components based on bio-based and / or recycled raw materials.For example, other additives besides the plasticizer, matrix-forming polymers, and filler can also be replaced by more sustainable alternatives. Preferably, bio-based pigments and / or bio-based dyes replace the conventional ones completely or partially in the functional layer. Alternatively or additionally, the functional layer can include more sustainable stabilizers. Examples of more sustainable stabilizers are antioxidants such as vitamin E, light stabilizers (e.g., chlorophyll), bio-based metal soaps (e.g., complexed stearic acids), or mixtures thereof.

[0044] According to the invention, the breathable multilayer composite comprises at least one functional layer and a substrate. The functional layer includes at least one foamed layer. Additionally, the functional layer can comprise one or more compact layers. In preferred embodiments, the functional layer comprises more than one layer. For example, the functional layer is formed from one or more compact layers and one or more foamed layers. For example, the functional layer is formed from up to four foamed layers.

[0045] The breathable multi-layer composite exhibits an air permeability determined according to DIN EN ISO 9237-1995 of at least 5 l / min / dm². 2 and at most 200 l / min / dm³ 2 preferably between 5 and 80 l / min / dm³ 2 and preferably between 10 and 60 l / min / dm³ 2 on.

[0046] Methods for creating water vapor permeability in multilayer composite materials according to the invention are generally known. For example, microperforations can be used, in which very small perforation holes are created with optionally heated needle rollers or punching tools; these holes are not visible to the naked eye. Such designs can result in significantly increased water vapor and air permeability while simultaneously being impermeable to liquids. A disadvantage is that when using polymeric materials such as PVC, especially during thermal stress above room temperature (23°C), the polymers flow, which at least partially closes the channels created by the microperforation, leading to a reduction or even the complete loss of the increased breathability effect. Therefore, within the scope of the present invention, breathability is improved by...

[0047] In preferred embodiments, the polymer composition for forming the functional layer comprises water, a surfactant, and / or a surfactant mixture. According to the teachings of EP4269099A1 and WO2023063896A1, these components lead to the spontaneous formation of micropores in a compact (i.e., non-foamed) polymer layer during drying. During the drying and gelling of the pasty mass, continuous openings or channels form at the respective phase or grain boundaries of these incompatible fractions (polymer / water), extending from one surface of the polymer layer to the other. For example, the size of the pores can be influenced by the amount of surfactant and the process parameters, thus adjusting the air and water vapor permeability.The surfactant or surfactant mixture contained in the compact polymer layer and the foamed polyurethane layer is generally suitable for stabilizing mechanically whipped foams and can be selected from the group consisting of ether sulfates, fatty alcohol sulfates, sarcosinates, organic amine oxides, sulfonates, betaines, amides of organic acids, sulfosuccinates, sulfonic acids, alkanolamides, ethoxylated fatty alcohols, sorbates, and combinations thereof. Emulsifiers for emulsion PVC can also be used as surfactants. These emulsifiers can be, among others, sulfonic acid or carboxylic acid esters. Particularly suitable foam-stabilizing surfactants are, for example, those marketed under the name Stokal by Bozetto (e.g., in the form of ammonium stearate (commercially available, for example, as Stokal® STA) and succinamate (commercially available, for example, as Stokal® STA).available as Stokal® SR) or the sodium salt of fatty acid alkyl polyglycol ether sulfates (commercially available, for example, as Stokal® SAF new)) or Ortegol from Evonik. Most preferably, the surfactant mixture contains a non-ionic surfactant such as Ortegol, and most preferably, the surfactant mixture is composed of non-ionic surfactants.

[0048] The surfactant content in the compact polymer layer can be varied within relatively wide limits, as long as the amount of surfactant in the compact layer is between 40 and 130 wt.% of the surfactant or surfactant mixture amount in the foamed polyurethane layer. A possible range for the surfactant content is 0.1 to 40 wt.%, based on the total weight of the compact polymer layer. Preferably, the amount of surfactant or surfactant mixture is 5 to 14 wt.%, and more preferably 6 to 10 wt.%.

[0049] In addition, the multilayer composite according to the invention preferably has a water vapor permeability of at least 3 mgcm' 2 h' 1 , further preferably of at least 5 mgcrrr 2 h' 1 and even more preferably in the range of 5 to 50 mgcrrr 2 h' 1 The properties of this multilayer composite are determined according to DIN EN ISO 14268.2-2013, Method C. Such a multilayer composite is capable of permeating a certain amount of water vapor and air. For example, when the multilayer composite is used as synthetic leather in seating furniture or clothing, this property leads to a temperature equalization between both sides of the synthetic leather and thus to a more comfortable sitting or wearing experience.

[0050] The breathable multilayer composite according to the invention can be, for example, artificial leather, a film, a foil, or a wall covering, for example, for interior and exterior applications, furniture, and applications in the automotive sector, particularly automobiles. Preferably, the multilayer composite is an artificial leather. The multilayer composite is particularly suitable for applications in the automotive sector or industry in general, such as furniture foils, floor coverings, wall coverings, automotive headliner applications, automotive interior applications, and / or seat materials. These applications can be found in the interior, exterior, mobility, or contract sectors, such as hotel chains, cinemas, home applications, aircraft, buses and trains, and cruise ships (nautical applications).

[0051] Examples

[0052] In this example, all liquid raw material components (these can be polymer dispersions, plasticizers, flame retardants, stabilizers, rheology aids, or pre-prepared batches of colorants, blowing agents, or fillers) were added and mixed with the solid components of the mixture (this includes polymer powders, stabilizers, flame retardants, fillers, rheology aids, color particles, and / or blowing agents) while stirring. Table 1 shows the exemplary compositions of the samples according to the invention “Expl” (filler is coffee grounds) and “Exp2” (filler is olive kernel flour), as well as the comparative example “V1” (no sustainable filler).

[0053] The coffee grounds used were commercially purchased (Inficaf from Bio-Bean Ltd) and have a particle size of 0.1 to 3000 pm. Drying and subsequent wet milling (impregnated in plasticizer and ground) resulted in a final average particle diameter of approximately 60 pm, determined according to ISO 13320:2020.

[0054] Table 1: Example recipes

[0055] The stirred mixture was spread onto the respective substrate in the desired layer thickness using a spreading process (e.g., with a knife). Curing was then initiated via a heating process with a temperature and residence time appropriate to the thickness and the specific formulation used. Several layers were built up successively, laminated onto a substrate, and cured.

[0056] Samples according to the invention were produced in the form of breathable synthetic leather (Expl and Exp2) and compared with a corresponding material with a lower sustainability content (V1).

[0057] The exemplary multilayer composite Expl was heated to a temperature of 50°C. A slight coffee odor was detected. No mold growth was observed over a period of 5 years.

[0058] Table 2 below shows some results of the measurements of mechanical and chemical properties. Table 2: Measurement of selected properties

[0059] The air permeability was not affected by the filler. Furthermore, the flexibility (100,000 bends at 23°C) and the abrasion resistance (Martindale 100,000 cycles MD100) of Expl and Exp2 were not affected. Additionally, the moisture content of approximately 10% water proved to be non-problematic. The thermal conductivity (TG) of the polymer matrix of these multilayer films (Expl, Exp2, V1) is approximately -20°C.

[0060] Expl and Exp2 also have a lower weight due to the use of sustainable materials.

[0061] Interestingly, it was also found that the coffee grounds in the breathable composite system (Expl) do not alter the water permeability, regardless of prior environmental influences. Under normal conditions (23°C / 50-60 RH), the coffee-infused synthetic leather had a permeability time of 60 s + / - 10 s for 0.5 ml of water. For the black synthetic leather (V1), this was 30 s. When the synthetic leather was dried at 100°C for at least 8 hours and the tests were repeated, the coffee-infused synthetic leather (Expl) retained a permeability time of 60 s + / - 10 s. The black-dyed material without coffee grounds had permeability times between 120 s and 460 s. This comfortable moisture-wicking property is achieved with 5% coffee grounds in the Expl. It is assumed that the carboxyl sterols in coffee oils, in combination with the fine pore structure of the ground coffee grounds, lead to this effect.Furthermore, it was found that the amount of water of 1 ml resulted in a comparable time of 60 s for coffee grounds material, and thus no differences in quantity were found within the framework.

Claims

Patent claims 1. Breathable multilayer composite comprising at least one textile substrate and one functional layer, wherein the multilayer composite has an air permeability of 0.1 to 200 ldnr 2 min' 1 , determined according to DIN EN ISO 9237-1995, and a water vapor permeability of 0.1 to 200 mgcrrr 2 h' 1 , determined according to DIN EN ISO 14268.2-2013 Method C, and wherein the breathable multilayer composite is based on at least 60 wt.%, based on the total weight of the multilayer composite, bio-based and / or recycled raw materials.

2. Breathable multilayer composite according to claim 1, wherein the functional layer comprises a bio-based and biodegradable filler.

3. Breathable multilayer composite according to claim 2, wherein the bio-based and biodegradable filler is coffee grounds powder and / or a filler based on native cellulose.

4. Breathable multilayer composite according to one of claims 1 to 3, wherein the functional layer comprises one or more at least partially bio-based or recycled polymers.

5. Breathable multilayer composite according to one of claims 1 to 4, wherein an at least partially bio-based or recycled polymer is produced from at least 30 wt.% biomass, based on the weight of the respective crude polymer.

6. Breathable multilayer composite according to one of claims 1 to 5, wherein the textile substrate is based on naturally occurring polymer fibers and / or recycled plastic fibers.

7. Breathable multilayer composite according to any one of claims 1 to 6, wherein the functional layer comprises a polyvinyl chloride and / or a polyurethane as the polymer matrix.

8. Breathable multilayer composite according to any one of claims 1 to 7, wherein the functional layer further comprises a bio-based or recycled plasticizer.

9. Breathable multilayer composite according to one of claims 1 to 8, wherein the multilayer composite is an artificial leather.

10. Breathable multilayer composite according to any one of claims 1 to 9, wherein the multilayer composite has an air permeability of 10 to 80 ldnr 2 min' 1 , determined according to DIN EN ISO 9237-1995.

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