Leather-imitating material made of persimmon mud and derived from plants

Abstract

The invention relates to a pure and reusable leather-type material of plant origin, which is at least 50% and preferably at least 80% bio-based. The material is based on a composition comprising a persimmon (Diospyros kaki) binder and a polymer derived from a polyol of plant origin. The invention also discloses a method for obtaining the material. The leather-type material may be used in various goods in textiles, such as garments, footwear products, or accessories. The material has been proved to maintain the same mechanical properties as animal-derived or synthetic leather, is a sustainable substitute, and also contributes to circular economy. The plant-derived leather-type sustainable material provides a substitute for known leather, and has little impact on the environment.

Description

[0001] The present invention relates to providing a natural, environmentally friendly, vegan and reusable leather-like material of plant origin. This material can be used for various goods in the textile field to replace leather from animal or synthetic sources. Background Art

[0002] People have been using materials derived from animal skins for a long time. Such materials are favored for their advantages such as strength, flexibility, durability, and aesthetic appearance. Animal skins can be applied to various types of consumer goods, such as clothing, furniture, automotive interiors, and many other retail products. The production of animal skins usually involves many issues related to environmental, health, or social problems (Sivaram and Barik, 2019. Energy from toxic organic waste for heat and power generation. Chapter 5. Woodhead Publishing Series in Energy. Pages 55 - 67). The production of animals used as raw materials for leather production requires a large amount of water, energy, and land, which causes livestock production to generate a large amount of greenhouse gases (CO2 and NH4). The production of animal skins also requires a large mixture of chemicals (such as chromium salts and dyes from heavy metals), which has an impact on the environment because it requires a large amount of water, has the potential to cause pollution, and is also toxic and carcinogenic, and may be harmful to human health and the environment when disseminated.

[0003] The use of animal furs has also attracted social attention. Many people oppose the use of animal furs because they are considered immoral. With the increasing demand to stop using animal skins, it is necessary to find alternative substitutes. One of the options considered to be more environmentally friendly is synthetic leather. Recently, the concern for sustainability in any industrial production field has led to an urgent reason to increase the use of natural materials and replace non-renewable fossil raw materials. Although leather is bio-based and renewable, these considerations have not led to a revival of leather. On the contrary, due to the continuous discussions about greenhouse gas emissions from cattle farming, the sustainability of leather production, and animal welfare, leather is facing greater pressure. At the same time, more and more people hope to consciously eat meatless foods or completely avoid any animal-source products. All these demands pose new challenges to cultural and material development.

[0004] Vegan leather refers to leather that does not contain any animal components in any of its processes. This leather is usually artificial leather, that is, synthetic leather. It is vegan because it is not of animal origin, but it contains plastic and thus is not ecological. This synthetic leather material is usually made from the petroleum-based products polyvinyl chloride (PVC) and polyurethane. Although synthetic leather may provide a solution to the problems in the production process of animal skins, PVC-based synthetic materials have not yet solved environmental problems. Raw materials derived from petroleum are not sustainable, and their production process uses additional chemical compounds (such as plasticizers) to make the synthetic leather more elastic. In addition, tanning leather also has a significant environmental impact. Currently, the vegan leather produced is not completely biodegradable. This is because each material is either made from a mixture of plants and polyurethane or is plant-based and coated with a plastic-based resin. There is a need for an environmentally friendly leather alternative that has an appealing appearance to consumers.

[0005] Vegetable leather is an alternative material to animal leather. It is produced from different components and waste materials, is always of plant origin, and is the most sustainable alternative to traditional animal skins, surpassing other products and synthetic materials. There is vegetable leather from mushrooms, pineapples, paper, wax cotton, teak leaves, apple fibers, grapes, kombucha, corn, grains, coconuts, hemp, white nettle, or cork. However, the leather made from these plants usually includes synthetic materials. However, in order to improve the structural characteristics and an appealing appearance to consumers, these leathers usually include synthetic polymer components such as polyurethane.

[0006] The circular economy is an economic system aimed at eliminating waste and continuously using resources. The circular system adopts the basic principles of reuse, sharing, repair, sharing, refurbishment, remanufacturing, and recycling to create a closed-loop system, minimizing the use or resource input and reducing the generation of waste, pollution, and carbon emissions. It is estimated that one-third of the food used for human consumption globally is lost or wasted, equivalent to 1.3 billion tons per year. Food loss and waste have become a much-concerned issue today. Therefore, the United Nations has reflected a higher awareness of this issue in the 2030 Agenda for the Sustainable Development and proposed that enterprises take measures to reduce food waste.

[0007] Although leather products produced from plant sources are natural alternatives to synthetic leather and leather of animal origin, they are usually obtained from crops grown specifically for this purpose, which is not sustainable and may even affect the natural environment.

[0008] Spain is the most important persimmon-growing country in Europe, with a total area of 18,601 hectares and a production of 492,320 tons. Currently, Spain is the second-largest persimmon producer in the world, accounting for 10.4% of the total persimmon production. In Spain, according to the data of the Spanish Ministry of Agriculture in 2017, the Valencian Community has 15,931 hectares of persimmon-growing area. This accounts for 86% of the national area and the production is 384,785 tons, accounting for 95% of the total Spanish production. In less than a decade, the growing area in the Valencian Community has increased sixfold, from 2,000 hectares to more than 13,000 hectares. Due to its excellent characteristics and growing area, "Kaki Ribera del Xúquer" is the only persimmon globally that has been recognized and has the Protected Designation of Origin mark. Unfortunately, due to market demand and possible pests and diseases, almost half of the harvest is wasted every year. The total quality and economic losses of persimmon producers are estimated to be 29.5% (based on the total production) or 38.5% (based on the final commercialized kilograms) on average. Therefore, millions of kilograms of potentially edible persimmons are wasted every year.

[0009] The prior art requires a biodegradable, natural, environmentally friendly, compostable, vegan, and reusable leather made from plant sources, which does not contain synthetic materials and forms part of the circular economy of the origin of the starting materials. Summary of the Invention

[0010] The present invention discloses a vegan leather-type material of plant origin comprising persimmons. The present invention has evolved from a circular economy project developed at the University of Valencia Science Park, Spain. Persimmon residues and samples that would otherwise have been discarded are reused in leather manufacturing. Using the method disclosed herein, no residues are left.

[0011] In a first aspect, the present invention relates to a composition for vegan leather, which comprises persimmons (Diospyros kaki) and a polymer derived from plant-based polyols. In a preferred embodiment, the persimmons can be selected from the Bright Red ("Rojo brillante") or Triumph varieties. In a more preferred embodiment, the ingredient is persimmons of the Bright Red ("Rojo brillante") variety.

[0012] The persimmon mass for use in the compositions of the present invention is selected from persimmon extracts, persimmon purees, persimmon pulp, or combinations thereof. In a preferred embodiment, the persimmon mass is persimmon puree or persimmon extract. The puree can be obtained by mixing and mashing the fruit by any known method in the art. The persimmon extract can be the product of Soxhlet extraction of persimmon fruits. The fruit slices or persimmon puree can be frozen after step a). In an embodiment, the persimmon mass is introduced directly into the process without freezing.

[0013] Leather is generally defined as animal skins that have been treated to preserve them for use in the manufacture of goods such as clothing, shoes, etc. For the purposes of the present invention, the expression "leather-like material" or "vegan leather" refers to a product that resembles leather of animal origin and can be used to manufacture the same consumer goods as leather. A plant or vegan source refers to a biogenic raw material (an organic material directly produced by the physiological activity of a plant rather than other elements such as fossil gases, coal, or petroleum) of biological precedence.

[0014] In the present invention, the expression "bio-based" is also used to refer to a product that is mainly composed of substances (or a plurality of substances) derived from living matter (biomass) and that is either naturally occurring or synthetic, or it may refer to a product made by a process using biomass. Bio-based materials are considered potential alternatives that are more environmentally friendly than their petroleum-based counterparts. (United States Environmental Protection Agency, EPA). The term has been widely extended and, in fact, there is an international labeling system that classifies materials as bio-based according to the percentage of renewable raw materials (% bio-based). Any 100% or plant-derived component will also be 100% bio-based. More definitions of bio-based products can be found at: https: / / single-market-economy.ec.europa.eu / sectors / biotechnology / bio-based-products_en.

[0015] Preferably, the composition comprises 20 - 60% wt., and / or 40 - 80% wt. of the total weight of the composition of the polymer. More preferably, the composition comprises 30 - 40% wt. of the total weight of the composition of persimmon and / or 60 - 70% wt. of the total weight of the composition of the polymer.

[0016] In an embodiment, the composition of the present invention comprises persimmons and plasticized starch derived from starch and plant-derived polyols. The starch is selected from the group consisting of corn, cassava, potato, or a combination thereof, and preferably the starch is corn starch. The polyol is selected from the group consisting of glycerol, erythritol, ribitol, and xylitol, and preferably the polyol is glycerol.

[0017] In another embodiment, the composition of the present invention comprises persimmons and a polymer, and the polymer is a polyurethane derived from plant polyols.

[0018] In the present invention, the term "polyurethane or PU derived from plant polyols" refers to a PU obtained by the reaction of a polyisocyanate with a polyol based on vegetable oils (such as soybean oil, safflower oil, cottonseed oil, linseed oil, peanut oil, olive oil, sunflower oil, canola oil, rapeseed oil, corn oil, palm oil, or a combination thereof). Non-limiting examples of the PU can be found in US20060276609A1, and non-limiting examples of the vegetable oil-based polyols can be found in US7786239B2.

[0019] In a preferred embodiment, the present invention provides a composition for a vegan leather-type material of plant origin, comprising:

[0020] 40 - 60% of bright red ("Rojo Brillante") persimmons;

[0021] 10 - 40% w / w of corn starch and

[0022] 2 - 20% w / w of glycerol.

[0023] In a more preferred embodiment, the material comprises approximately 59% w / w of bright red (Rojo Brillante) persimmons, approximately 27% w / w of corn starch, and approximately 14% w / w of glycerol. The term "about" should be interpreted as an error range of ±2% w / w.

[0024] The composition may further comprise a dye of plant origin. The dye provides the desired color to the final product. In a preferred embodiment, there is 1 - 2% wt. of the dye based on the total weight of the composition. In a preferred embodiment, the amount of the dye is 0.1 - 1% wt. The dye can be selected from any plant-derived dye, such as dyes from Acacia catechu, Garcinia hanburyi resin, chestnut shells, Rheum emodi, Indigofera tinctoria leaves, Mallotus philippensis fruits, Rubia cordifolia roots, mangosteen peels, Terminalia chebula fruits, pomegranate peels, Citrus maxima leaves, Genista tinctoria, or charcoal, etc. In a preferred embodiment, the dye is charcoal.

[0025] In a preferred embodiment, the composition of the present invention further comprises a vegetable oil in an amount of 1-10% wt. based on the total weight of the composition, and the vegetable oil is selected from sesame oil, canola oil, sunflower oil, soybean oil, peanut oil, olive oil, corn oil, bean oil, grapeseed oil, jojoba oil, palm oil, cottonseed oil, almond oil, safflower oil, walnut oil, avocado oil, rice bran oil and linseed oil.

[0026] In another preferred embodiment, the composition of the present invention further comprises an additive in an amount of 0.5-2% wt. based on the total weight of the composition, and the additive is selected from thickeners, crosslinking agents and stabilizers. These additives are well-known to those skilled in the polymer art.

[0027] Another aspect of the present invention relates to a vegan leather material comprising the persimmon-based composition as described above.

[0028] In a preferred embodiment, the material is a laminated material, and the laminated material comprises the following layers:

[0029] a) a top layer comprising aqueous polyurethane,

[0030] b) a second layer comprising the composition according to claims 1-9,

[0031] c) a third layer comprising aqueous polyurethane having adhesive properties, and

[0032] d) optionally, a fourth layer which is a textile layer.

[0033] The aqueous polyurethane used to obtain such a laminated material of the present invention can be any one known in the art. It can be used in the form of a dispersion, which is a binary colloidal system in which polyurethane particles are dispersed in a continuous aqueous medium. The concept of producing water-based polyurethanes aims to produce polymers with a large number of hydrophilic groups to obtain water solubility. The properties of these aqueous polyurethanes make them very suitable for a wide range of applications. These environmentally friendly polymers are non-toxic, non-flammable, and they do not pollute the air or produce waste water. Since only water evaporates during the process, these systems are harmless to the environment. Aqueous polyurethanes are important in many industrial applications, such as coatings, adhesives, ink binders, glass fibers, paper sizing, synthetic leather, biomaterials, membranes and packaging films, and waterproof textiles.

[0034] In another preferred embodiment, layer (a) accounts for 10-20% wt. of the total weight of the material, and / or layer (b) accounts for 20-70% wt. of the total weight of the material, and / or layer (c) accounts for 2-10% wt. of the total weight of the material, and / or layer (d) accounts for 30-50% wt. of the total weight of the material.

[0035] In another embodiment, the top layer (a) of the material is coated with a composition comprising wax and vegetable oil in a preferred ratio of 1:1. The wax can be selected from beeswax, carnauba wax, lignite wax or candelilla wax, preferably beeswax. The oil can be selected from any vegetable oil, such as sesame oil, canola oil, sunflower oil, soybean oil, peanut oil, olive oil, corn oil, legume oil, grapeseed oil, jojoba oil, palm oil, cottonseed oil, castor oil, almond oil, safflower oil, walnut oil, avocado oil, rice bran oil and linseed oil. Preferably, the vegetable oil is olive oil.

[0036] The top layer (a) is formed of aqueous polyurethane and is deposited on a layer (b) of a composition comprising persimmons. In a preferred embodiment, the polyurethane accounts for 10 - 20% wt. of the total weight of the layered material, preferably about 17% wt. Preferably, the polyurethane layer is at least 45% bio-based.

[0037] The second layer (b) is formed of the composition comprising persimmons described above and can be adjusted by modifying the percentage of its components to change the softness, flexibility and mechanical resistance of the final material. This layer accounts for 20 - 70% wt. of the total weight of the layered material, preferably about 50% wt.

[0038] The third layer (c) is an adhesive layer located between the second layer (b) and the textile layer. In a preferred embodiment, the adhesive accounts for 2 - 10% wt. of the total weight of the layered material, preferably about 7.5% wt. Preferably, the adhesive layer is at least 50% bio-based. In a preferred embodiment, the adhesive is an aqueous polyurethane adhesive. The polyurethane and the adhesive can be any components (polyurethane or adhesive respectively), provided that they are solvent-free and have a high percentage of bio-based materials. Non-limiting examples of such polyurethanes can be found in EP2554559B1.

[0039] The textile layer is preferably made of plant fibers and has a mechanical support function. This layer can be selected from any textile composed of 100% plant sources (such as cotton, seeds, coconuts, linen, etc.). In a preferred embodiment, the textile layer is 100% cotton. The textile layer accounts for 30 - 50% wt. of the total weight of the layered material, preferably about 37% wt.

[0040] The layered material of this embodiment has the following structure from top to bottom: polyurethane, material comprising persimmons, adhesive and 100% textile layer.

[0041] In a preferred embodiment, the width of each layer is such that: the thickness of layer (a) is 0.05 - 0.30 mm, and / or the thickness of layer (b) is 0.20 - 1.50 mm, and / or the thickness of layer (c) is 0.05 - 0.20 mm, and / or the thickness of layer (d) is 0.20 - 0.50 mm. The width of the final material is about 0.6 - 2.5 mm. The term "about" shall be interpreted as an error range of ±2% of the above values.

[0042] The layered material must be at least 50% bio-based, preferably at least 80% bio-based, and more preferably at least 85%.

[0043] Any leather-type material of the present invention disclosed above has an appearance and mechanical characteristics similar to those of leather of animal origin or synthetic leather. The mechanical properties of the materials of the present invention, such as single tear strength, tensile strength, rubbing fastness, flexibility, and average thickness, are comparable to those of leather materials in the prior art, which means they are suitable as substitutes for these materials. The demonstration of these properties will be shown in the examples.

[0044] In a third aspect, the present invention relates to a method for obtaining the layered material described above, the method comprising the following steps:

[0045] a) depositing a first layer of aqueous polyurethane on a support;

[0046] b) drying the polyurethane of step a) for 1 - 10 minutes at a temperature of 100 - 120 °C;

[0047] c) adding a layer of the composition comprising persimmon described above to the dry polyurethane of step b);

[0048] d) drying the two layers for 5 minutes to 2 hours at a temperature of 70 - 150 °C;

[0049] e) adding a third layer of aqueous polyurethane having adhesive properties to the layer comprising persimmon dried in step d), and optionally adding a textile layer above the adhesive layer of step e);

[0050] f) drying for 1 - 5 minutes at a temperature of 100 - 150 °C.

[0051] In order to imitate the appearance of leather on the top layer of the vegan leather material of the present invention, the support on which the first layer is deposited in step a) presents a pattern to emboss the pattern onto the top layer (a). This can be done with embossing paper, which will define the surface design of the material. Although embossing paper imitating the appearance of animal leather is desirable, any embossing paper can be used. Another option is to use an ironing machine with the desired pattern and press it on the top layer to give it this imitated shape.

[0052] For embodiments in which the persimmon composition comprises a starch-derived polymer, the starch is dissolved in distilled water and heated. In a preferred embodiment, the starch is in the form of starch granules. The solution is continuously stirred and heated at a temperature of 70 - 80 °C until the starch is completely dissolved. Importantly, the starch molecules are dispersed in hot water to avoid crystallization of the starch through gelatinization. The temperature range is important because a temperature of 70 to 80 °C avoids starch degradation. The melting temperature of native starch is higher than the decomposition temperature. When the temperature is higher than this range, the starch may lose its equilibrium moisture within the granules and start to degrade before dissolution. The starch can be selected from the group consisting of corn, cassava, potato, or a combination thereof. In a preferred embodiment, the starch is corn starch. In a more preferred embodiment, the starch is corn starch granules. The amount of starch is 5 - 20% w / v relative to distilled water, preferably 10 - 20 / w / v, more preferably 16% w / v.

[0053] For the purposes of the present invention, the expressions "thermoplastic starch", "plasticized starch", "pseudo-thermoplastic starch" are equivalent and refer to a homogeneous material formed by the combination of gelatinized starch and a polyol. In a first stage, the polyol (preferably of plant origin) is added to the gelatinized starch, and in a second stage, the mixture is heated at 70 - 80 °C until a translucent gel phase is formed under continuous stirring. The amount of polyol is 40 - 60% w / w of the amount of starch added in step b), preferably 50% w / w. In a preferred embodiment, the polyol is selected from the group consisting of glycerol, D-sorbitol, galactitol, mannitol, pinitol, arabitol, ribitol, erythritol, threitol, xylitol (cylitol), volemitol, perseitol, and meso-inositol. In a more preferred embodiment, the polyol is glycerol. The polyol forms hydrogen bonds with the starch molecules, thereby increasing its molecular mobility by utilizing the action of the hydroxyl groups of the starch molecules and making the starch exhibit plasticity. It is necessary for all the granules of the starch to be completely turned into a translucent gel phase to form pseudo-thermoplastic starch. In a preferred embodiment, the glycerol (CAS number 56 - 81 - 5) in step c) is of plant origin. It can be obtained from heated coconut oil, soybean oil, or palm oil pressurized with water, such that the glycerol decomposes into the water. The glycerol is then separated by distillation. Glycerol can also be obtained as a by-product of soap or biodiesel manufacture. Glycerol is also a waste product from biodiesel production, and thus the use of glycerol from this process also improves the sustainability of the method of the present invention (Gu Y and Jerome F, 2010. Green Chemistry 12; 1127 - 38). The combination of water and glycerol enhances the flexibility of the material by increasing the molecular spacing and reducing the intramolecular hydrogen bonds along the starch polymer chains.

[0054] Then, a persimmon base material of 20 - 40% w / v is introduced into the thermoplastic starch of the previous step. In a preferred embodiment, the amount of the added persimmon base material is 20 - 25% w / v. The mixture is stirred until a homogeneous substance or composite material is formed. The persimmon base material acts as a binder in the mixture, thus forming a composite material. The persimmon as a binder improves the rigidity of the material, thereby preventing the polymer from becoming too brittle due to water loss, and also improves the thermoplasticity of the starch. The combination is mixed until completely homogeneous.

[0055] In another embodiment, a plant - derived dye can be added in the previous step. The dye provides the desired color for the final product. In a preferred embodiment, 0.1 - 1% w / v of the dye is added to the mixture. In a more preferred embodiment, the amount of the dye is about 0.5% w / v of the mixture. The dye is selected from any plant - derived dye, such as dyes from Acacia catechu, Garcinia hanburyi resin, chestnut shells, Rheum emodi, Indigofera tinctoria leaves, Mallotus philippensis fruits, Rubia cordifolia roots, mangosteen peels, Terminalia chebula fruits, pomegranate peels, Citrus maxima leaves, Genista tinctoria, or charcoal, etc. In a preferred embodiment, the dye is charcoal. Charcoal is a plant dye that is stable under high temperature, light, and pH, and it can also provide antibacterial properties to the leather obtained by the method disclosed above. Activated carbon (such as charcoal) remains stable at temperatures far above 900°C.

[0056] Subsequently, the homogeneous composite material is placed between a mold and a 100% cotton fiber material sheet. The mold determines the design of the material. In this example, a mold similar to the surface of an animal - derived material can be used. The material is introduced into the mold to form a layer with a thickness of 3 - 10 mm. The 100% cotton fiber sheet is placed on the composite material layer. The sandwich structure is subjected to a curing process, which includes placing the structure in an oven and heating it at 60 to 80°C, preferably about 70°C, for 1 - 20 hours, preferably 1.5 - 4 hours. After this curing step, the material is kept at room temperature for 12 to 24 hours. The cooling time at room temperature will depend on the curing time in step e). The shorter the curing time, the shorter the standing time. Once the standing time ends, the material sheet is removed from the mold to obtain a leather - like material. The size of the material sheet depends on the size of the mold, and its thickness is about 0.6 to 2.5 mm after step e).

[0057] The composition of the homogeneous composite material in step e) comprises 20 - 40% w / v of persimmons, 5 - 20% w / v of starch, 2 - 12% v / v of glycerol, and 28 - 73% v / v of water, where the percentages refer to the final amount of the homogeneous composite material. In a preferred embodiment, the homogeneous composite material in step e) comprises 20 - 25% w / v of persimmons, 7 - 15% w / v of starch, 3 - 6% w / v of glycerol, and 54 - 70% v / v of water, where the percentages refer to the final amount of the homogeneous composite material. In a more preferred embodiment, the homogeneous composite material further comprises 0.1 - 1% w / v of a plant-derived dye.

[0058] To coat the top layer of the laminated material, the wax and oil are heated and mixed. The formulation is cooled at room temperature and applied to the material obtained in step e). The coated material is introduced into an oven and heated at 60 - 80 °C, preferably 70 °C, for 2 - 10 minutes. Additional coatings can be added by repeating the same process described herein.

[0059] In another embodiment, the leather-type material is further enhanced with a SCOBY (symbiotic culture of bacteria and yeast) using a bacterial or yeast culture. SCOBY is a biopolymer obtained by fermenting kombucha beverages produced from tea (black / green tea) and sugar. The SCOBY layer obtained after kombucha fermentation can be added to the top of the dried leather or added to the formulation or both to form a composite material with enhanced properties. The culture is added after step e) or added to the composite material in step d).

[0060] In a preferred embodiment, the polyurethane in step a) accounts for 10 - 20% w / w of the total weight of the four-layer material, preferably about 17%. The polyurethane layer is preferably at least 45% bio-based. In a preferred embodiment, the polyurethane is a waterborne polyurethane.

[0061] In a preferred embodiment, step b) is carried out at 100 °C for 2 minutes. In another preferred embodiment, step d) is carried out at 70 °C for 1 hour 30 minutes. In another preferred embodiment, step f) is carried out at 100 °C for 2 minutes.

[0062] The composition of the intermediate layer in step c) can be adjusted by modifying the percentages of its components to change the softness, flexibility, and mechanical resistance of the final four-layer material. This layer accounts for 20 - 70% w / w of the total weight of the four-layer material. In a preferred embodiment, the adhesive in step e) accounts for 2 - 10% w / w of the total weight of the four-layer material, preferably about 7.5% w / w. The adhesive layer is preferably at least 50% bio-based. In a preferred embodiment, the adhesive is a waterborne polyurethane adhesive. The polyurethane and the adhesive can be any composition (polyurethane or adhesive respectively), provided that they are solvent-free and have a high percentage of bio-based materials.

[0063] The textile layer in step e) can be selected from any textiles composed of 100% plant sources (such as cotton, seeds, coconuts, linen, etc.). In a preferred embodiment, the textile layer is 100% cotton. The textile layer accounts for 30 - 50% w / w of the total weight of the four-layer material, preferably about 37% w / w.

[0064] In a fourth aspect, the present invention relates to an article comprising the above-mentioned vegan leather material. The article can be a textile product, footwear, leather goods, bookbinding, frame, luggage, furniture, watchband, cover, bracelet, handle, basket, keychain or face mask. The leather of the present invention can be used in any article where animal leather or synthetic leather is used.

[0065] In a fifth aspect, the present invention relates to the use of persimmon (Diospyros kaki) for manufacturing textiles, preferably vegan leather. The material obtained from persimmon fruits can be used in combination with the above-mentioned polymers to manufacture textiles having the same properties and appearance as genuine leather.

[0066] Although other types of leather-like materials from plant sources have been disclosed, due to its inherent characteristics, persimmon is not a fruit that would be considered for selection by those skilled in the art. Due to the low number of fibers in its composition (about 1% w / w), persimmon lacks the ability to form a 3D matrix that can provide the necessary strength and flexibility of the material. In addition, due to differences in color, particle size and surface smoothness, the surface of this fruit usually has many defects. These characteristics would make those skilled in the art less inclined to use persimmon and instead use other plants. The leather-like material disclosed herein provides an alternative to known leathers, which has a smaller environmental impact and also promotes a circular economy by utilizing surplus persimmons that do not enter the consumer's table. The innovative new material of the present invention is designed to simulate the structure of leather as a single-layer or multi-layer material, thus promoting a circular economy and zero waste of persimmons. Moving towards a more circular economy can bring benefits such as reducing pressure on the environment, improving the security of raw material supply, enhancing competitiveness, stimulating innovation, promoting economic growth and creating job opportunities. This project is a sustainable solution to the need for developing plant-based eco-friendly leather as a substitute for synthetic leather and natural leather, minimizing the environmental and health impacts of petroleum-derived raw materials.

[0067] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art of the present invention. Methods and materials similar or equivalent to those described herein can be used in the practice of the present invention. Throughout the specification and claims, the word "comprising" and its variants are not restrictive and are not intended to exclude other technical features, additives, components or steps. The term "comprising" also includes the term "consisting of". BRIEF DESCRIPTION OF THE DRAWINGS

[0068] The following drawings illustrate the present invention and should not be construed as limiting the invention in any way.

[0069] Figure 1 . Manufacture of leather-type materials of plant origin. A. Gelatinization of corn starch in water. B. Plasticization of gelatinized corn starch. C. Thermoplastic gel.

[0070] Figure 2 . Composition layer in a mold with leather texture. A. Top view. B. Side view.

[0071] Figure 3 . Leather-type materials of plant origin obtained by the method of the present invention. DETAILED DESCRIPTION

[0072] The present invention is illustrated in the examples as well as in the drawings and general schemes. Unless otherwise indicated, the substituents and integers used in the following schemes are as defined in the embodiments of the present invention. This section is intended to assist in understanding the present invention and should not be construed as limiting the present invention as set forth in the claims in any way.

[0073] Example 1: Making vegan leather with persimmons and polymers derived from starch and plant - sourced polyols.

[0074] Persimmon pieces of the bright red variety from the Ribera del Xúquer region of Valencia (Spain) were collected. The fruits were mixed and frozen at -20 °C until use. The persimmons were thawed and a base material was obtained. The fruit base material for leather production can be the mud produced by mechanically crushing the fruit pieces, the residue obtained by Soxhlet extraction of persimmon fruits, the pulp, or persimmons in a combined form thereof. In this example, persimmon mud was used. The base material was weighed and reserved. 10 g of corn starch was dissolved in 62.5 g of distilled water at 80 °C with continuous stirring until a gel was formed at 70 - 80 °C. The solution was maintained at this temperature for 30 minutes until a nearly translucent gel was formed. Figure 1 A shows the appearance of corn starch granules dissolved in water. 5 g of glycerol was added to the solution with stirring and heated at 70 - 80 °C for about 10 minutes. At this time, the gelation process began, the stirring speed was increased to avoid agglomeration (e.g., 2500 rpm), and the mixture was continuously stirred at 80 °C for 10 minutes with a manual stirrer. Figure 1 B shows the gelatinized corn starch after adding glycerol. Stirring was continued under heating until complete gelation of the starch molecules occurred. This moment was determined because the mixture presented a uniform and translucent appearance ( Figure 1C). All starch granules are completely transformed into a translucent gel phase, known as "glycerol plasticized starch (GTPS) or plasticized starch". Once the homogeneous GTPS is produced, the product is weighed. 22 g of persimmon base material is added to 77.5 g of plasticized starch. In this step, 0.5 g of dyed charcoal is also added to obtain the final black color. The purpose of adding the dye is merely to provide the desired color for the final material, and it is not an essential component in the mixture. The mixture is continuously mixed until it is completely homogeneous, thus obtaining the composite material. Complete homogenization is very important for obtaining a uniform particle size. Once the mixture is completely homogeneous, it is added to a mold with a pattern mimicking animal leather. Figure 2 Shows a mold with leather texture and the composite material.

[0075] Example 2: Making coated vegan leather with persimmons and starch - sourced polymers.

[0076] A layer of 100% cotton fiber is placed on top of the composite material obtained in Example 1. After assembly, the sandwich is placed in a forced air drying oven. After that, the sandwich is left at room temperature for another 24 hours. Finally, the material is removed from the mold. Figure 3 Shows the leather-type material obtained after this process. The appearance is the same as that of leather from animal sources. To obtain a protected material with waterproof properties, a coating is added to the material obtained in Example 1. Natural beeswax and olive oil are mixed at a ratio of 1:1 (w / w) under heating at 40 °C until the wax is completely dissolved. The solution is cooled and evenly applied to the leather-type material. After 2 minutes in an oven at 70 °C, the excess coating is removed, and the material is dried again at 70 °C for 2 minutes. Another layer of the mixture is added, and the process is repeated.

[0077] Example 3: Making 4 - layer vegan leather with persimmons and starch - sourced polymers.

[0078] To expand the uses of the material of the present invention, a leather-like material formed of four layers is developed. Aqueous polyurethane is added to embossed paper and cured at 100 °C for 2 minutes. The aqueous polyurethane is >47% bio-based. After drying this layer, a layer of the material obtained in Example 1 is added on the polyurethane layer (top layer), and the two layers are cured at 70 °C for 1 hour and 30 minutes. After drying, an adhesive layer of aqueous polyurethane adhesive is added on the layer including persimmon (middle layer), and finally a 100% cotton textile layer is added. The structure with four layers is cured at 100 °C for 2 minutes. After the material is completely dried, the embossed paper is removed. This material is designed to mimic the structure of leather as a multi-layer material. The textile support (100% cotton) fulfills the mechanical functions. The middle layer including persimmon not only determines the feel and softness of the final material but also determines the flexibility and mechanical resistance of the upper polyurethane layer. Table 1 discloses the distribution of each layer of the material and the percentage of bio-based elements in the final material:

[0079] Table 1

[0080]

[0081] It can be concluded from this table that the total bio-based content in the material is higher than 85%.

[0082] Example 4: Characterization of laminated vegan leather

[0083] The mechanical properties of the material of Example 3 were compared with commercial materials of animal origin. Two tests were selected to determine the abrasion resistance and the color fastness to cyclic reciprocating friction. The abrasion resistance was determined using the standard method EN 13520:2001 / A1:2004). This method was carried out in a Martindale wear testing machine at a test pressure of 12 Pa. Table 2 shows the determination results. The results show that the material of the present invention passed the abrasion resistance test as well as other commercial leathers, which makes the material suitable for use in clothing and commodity manufacturing.

[0084] Table 2

[0085]

[0086] (*) Commercially available

[0087] The color fastness was determined according to ISO 11640:2018. This method involves how the leather should perform in a test with a given number of forward and backward movements using a standard wool sheet. The color change during the test was evaluated using a standard gray scale. When carrying out this test, any other visible changes or damages on the leather surface should also be reported. The value should be grade 5, which is the best and highest grade, and any lower value indicates a color change. Commercial brands and manufacturers require that the value of this test be at least 4 at the end of the cycle. Table 3 shows the test results. In this case, the material of the present invention has a behavior similar to that of animal leather, and at 6400 cycles, it shows grade 4 and slight peeling of the coating, both of which are acceptable in the textile industry.

[0088] Table 3

[0089]

[0090] (*) Commercially available

[0091] When leather is used for objects in foot contact or on the non-contact side of the foot, the standard is carried out at 100 cycles and 50 cycles, and the required maximum grade for passing is equal to or higher than gray scale grade 3. The above results show that the grade of each material after several cycles is the average result. The material of the present invention obtained 5 points in all tests, which were carried out at 150 cycles, while other materials were carried out at 100 cycles, or at 50 cycles, and other materials were carried out at 10 - 50 cycles. These results indicate that the material of the present invention has very good performance, even superior to other commercial leathers. These results show that the performance of the material of the present invention meets the two most important tests required by natural leather manufacturers and designers.

[0092] Example 5: Making vegan leather with persimmons and PU formed from isocyanate and plant - sourced polyols.

[0093] Persimmon puree was obtained as described in Example 1. 48 g of this persimmon base was mixed with 46 g of PU from natural sources, and the mixture was stirred. During stirring, 5 g of soybean oil and 1 g of natural pigment were added to the mixture, and stirring was maintained for 5 - 10 minutes. To manufacture the multi-layer vegan leather material, the mixture of aqueous PU and additives was added to the embossed paper that imparts texture to the final top layer, obtaining a layer with a thickness of less than 200 microns. The layer was dried in a ventilated oven at T higher than 100 °C for several minutes to obtain the top layer. Then, the previously obtained mixture based on the persimmon base was added to this dried top layer. The application was carried out using continuous and slow flow and could have different thicknesses, depending specifically on the target thickness of the final sample. It was dried in a ventilated oven at T higher than 100 °C. A bio-based PU adhesive was prepared and applied to the dried persimmon layer and the organic support (cotton cloth in this example). The two layers were pressed together and then placed in the oven to dry for several minutes. Finally, the product was cured in the oven at a temperature of 135 - 140 °C for 3 - 5 minutes. In the resulting material, layer (a) accounted for 11% wt., layer (b) accounted for 51% wt., layer (c) accounted for 8% wt., and layer (d) accounted for 30% wt. relative to the total weight of the layered material.

[0094] Example 6: Study on the physical and mechanical properties of laminated materials of vegan leather made from persimmons and PU.

[0095] The purpose of this study is the comparison between the characteristics of the vegan materials of the present invention and the existing products on the market, as shown in the following table:

[0096] Table 4: Standardized tests for measuring each characteristic

[0097]

[0098] Table 5: Test results applied to natural growth materials

[0099]

[0100] Table 6: Test Results for Textiles with Different Coatings

[0101]

[0102] Table 7: Test Results for Non-woven Fabrics of Plant Materials

[0103]

[0104] Regarding thickness, it can be seen that some products have a larger thickness while some have a smaller thickness. Thus, the vegan leather of the present invention is consistent with similar products, with 36% of competing products having a value higher than this and 64% lower than this.

[0105] The laminated quality is a very important characteristic among the physical parameters of the product, which depends on the textile substrate used and the deposited persimmon intermediate layer.

[0106] The tensile strength test evaluates the resistance of the fabric itself when subjected to a certain force until it breaks. From the results, it can be seen that the breaking strength value of the vegan leather of the present invention is also consistent with the results of competing products: 45% of competing products have a value higher than this and 55% lower than this. The elongation resistance can only be compared with that obtained from fruit leather. From this example, it can be seen that the value of fruit leather is higher, although the value of 26.74% obtained for the vegan leather of the present invention is already an acceptable value for the clothing market (the market that most requires this characteristic).

[0107] Tear resistance is a characteristic of greater importance in the fashion clothing, interior decoration, contract, and footwear markets. In this example, the value obtained for the vegan leather of the present invention is much higher than that of other products, second only to natural leather.

[0108] The water vapor permeability test determines the breathability of the product, which is an important characteristic in the clothing market. Although the breathability value is 85% lower compared to natural leather, compared to other products, 45% have a higher value and 55% have a lower value. Thus, it can be said that the vegan leather of the present invention is consistent with the results of other commercial products.

[0109] The results obtained in the flexural strength test are very favorable for the vegan leather of the present invention because their values are higher than those of other products and are at the same level as natural animal leather.

[0110] This color fastness to artificial light test determines the resistance of the product to color degradation caused by continuous exposure to artificial light, and this characteristic has a greater impact on the automotive and contract markets.

[0111] The vegan leather of the present invention has only been compared with fruit leather, and it can be seen that the color resistance value of the vegan leather of the present invention is significantly between 125 - 150%. According to the UNE-EN 14465:2004 / A1 standard, within the performance levels from A to E, the vegan leather of the present invention will be at level A, which is very advantageous for the upholstery, automotive, and contract markets.

[0112] Abrasion resistance is more common in the footwear or upholstery markets. Only the value of this property has been measured for the vegan leather of the present invention, and according to the UNE-EN 14465:2004 / A1 standard, within the performance levels from A to E, the product will be at level B, which is very advantageous for the upholstery market.

Claims

1. A composition for vegan leather, the composition comprising persimmon (Diospyros kaki) and a polymer derived from plant - sourced polyols.

2. The composition according to claim 1, wherein, the persimmon accounts for 20 - 60% wt. of the total weight of the composition, and the polymer accounts for 40 - 80% wt. of the total weight of the composition.

3. The composition according to the preceding claim, wherein, the persimmon accounts for 30 - 40% wt. of the total weight of the composition, and the polymer accounts for 60 - 70% wt. of the total weight of the composition.

4. The composition according to any one of the preceding claims, wherein, the polymer is a plasticized starch derived from starch and plant - sourced glycerol, preferably the starch is corn starch.

5. The composition according to any one of claims 1 - 3, wherein, the polymer is a polyurethane derived from plant polyols.

6. The composition according to any one of the preceding claims, further comprising a plant - sourced dye accounting for 0.1 - 1% wt. of the total weight of the composition.

7. The composition according to any one of the preceding claims, further comprising a vegetable oil accounting for 1 - 10% wt. of the total weight of the composition, the vegetable oil being selected from sesame oil, rapeseed oil, sunflower oil, soybean oil, peanut oil, olive oil, corn oil, bean oil, grapeseed oil, jojoba oil, palm oil, cottonseed oil, almond oil, safflower oil, walnut oil, avocado oil, rice bran oil, and linseed oil.

8. The composition according to any one of the preceding claims, further comprising an additive accounting for 0.5 - 2% wt. of the total weight of the composition, the additive being selected from thickeners, cross - linkers, and stabilizers.

9. A vegan leather material comprising the composition according to any one of claims 1 to 8.

10. The material according to claim 9, which is a laminated material, the laminated material comprising the following layers: a) a top layer comprising aqueous polyurethane, b) a second layer comprising the composition according to claims 1 - 9, c) a third layer comprising aqueous polyurethane having adhesive properties, and d) optionally, a fourth layer which is a textile layer.

11. The material according to claim 10, wherein, layer (a) accounts for 10 - 20% wt. of the total weight of the material, and / or layer (b) accounts for 20 - 70% wt. of the total weight of the material, and / or layer (c) accounts for 2 - 10% wt. of the total weight of the material, and / or layer (d) accounts for 30 - 50% wt. of the total weight of the material.

12. The material according to any one of claims 10 or 11, wherein, layer (a) is coated with a composition comprising wax and vegetable oil.

13. The material according to claim 12, wherein, the wax and the vegetable oil are in a 1:1 ratio.

14. The material according to any one of claims 12 or 13, wherein, the wax is selected from beeswax, montan wax, candelilla wax, and carnauba wax.

15. The material according to any one of claims 11 to 15, wherein the vegetable oil is selected from sesame oil, canola oil, sunflower oil, soybean oil, peanut oil, olive oil, corn oil, legume oil, grapeseed oil, jojoba oil, palm oil, cottonseed oil, almond oil, safflower oil, walnut oil, avocado oil, rice bran oil, and linseed oil.

16. The material according to any one of claims 11 to 15, wherein, the thickness of layer (a) is 0.05 - 0.30 mm, and / or the thickness of layer (b) is 0.20 - 1.50 mm, and / or the thickness of layer (c) is 0.05 - 0.20 mm, and / or the thickness of layer (d) is 0.20 - 0.50 mm.

17. A method for obtaining the layered material according to claims 10 - 16, which comprises the following steps: a) depositing a first layer of aqueous polyurethane on a support; b) drying the polyurethane of step a) at a temperature of 100 - 120 °C for 1 - 10 minutes; c) adding a layer of the composition comprising persimmon according to any one of claims 1 to 8 to the dry polyurethane of step b); d) drying the two layers at a temperature of 70 - 150 °C for 5 minutes to 2 hours; e) adding a third layer of aqueous polyurethane having adhesive properties to the dried persimmon - containing layer of step d), and optionally adding a textile layer above the adhesive layer of step e); f) drying at a temperature of 100 - 150 °C for 1 - 5 minutes.

18. The method according to claim 17, wherein, the support of step a) has a pattern to imprint the pattern onto the top layer (a).

19. An article comprising the vegan leather material according to claims 10 - 16.

20. The article according to claim 19, selected from textile products, footwear products, leather goods, book bindings, frames, luggage, furniture, watch straps, covers, bracelets, handles, baskets, keychains, or face masks.

21. Use of persimmon (Diospyros kaki) for the manufacture of vegan leather.

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