Finished leather substitute

Abstract

To solve the problem in which: finishing the top surface of materials grown from mycelium as leather substitutes is not fully satisfying yet, according to the recognition of the inventors.SOLUTION: The invention relates to a method for producing a finished leather substitute, which method comprises the step of providing a sheet material grown from mycelium, which sheet material shows a top surface layer and a bottom surface, wherein the method comprises the step of applying at least one finishing coating on the bottom surface only.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a finished leather substitute, a finished leather substitute obtained by such a method, and their uses.

Background Art

[0002] Leather is used in a very wide variety of applications, including furniture upholstery, clothing, shoes, luggage, handbags and accessories, and automotive applications. Currently, animal skins are used as raw materials for natural leather. Synthetic leathers have been developed in which natural or synthetic fibers are coated with a synthetic polymer such as polyurethane or polyvinyl chloride. Although many materials are used, most synthetic leathers are composed of a polyester knit base coated with polyurethane and polyvinyl chloride. The processing of these microplastic, non-biodegradable plastic-based products, as well as their lifespan and end-of-life, are far from being environmentally friendly. Furthermore, such synthetic leathers lack the quality, durability, and reputation of natural leather.

[0003] Therefore, the current trend is towards the use of non-petroleum-based materials, especially those of plant origin. Fungal-based materials, especially mycelium-type materials, are natural materials, whether composite or not, and are obtained by the growth of fungal materials. Their growth is controlled to obtain various shapes, sizes, and densities. Materials obtained from mycelium, such as those described in international application WO2018014004 (Mycoworks), US patent application 2015 / 0033620, or US patent 9,485,917 (Ecovative Design), or international application WO2020237201 (Bolt threads), make it possible to manufacture materials in the form of thick sheets that can be used as substitutes for leather.

[0004] However, before they can be used as leather substitutes, these raw materials need to be processed, typically stabilized, plasticized, and ennobled. Ennobling of the material can include coloring the material, altering its flexibility, mechanical properties, density, and adding some coating or finish to the surface of the material to improve color uniformity, water repellency, and smooth feel. Summary of the Invention Problems to be Solved by the Invention

[0005] The inventors recognized that finishing the upper surface of a material grown from mycelium as a leather substitute is not yet entirely satisfactory. They lack homogeneity, and some regions on the upper surface are denser, more or less hydrophobic, or more or less porous, which has led to non-uniform adhesion, coloring, and plasticization and lubrication of the surface of the topcoat. Furthermore, the inventors have demonstrated that the upper surface did not allow penetration of the aqueous solution due to its high surface fiber density and more hydrophobic nature.

[0006] Next, the inventors made a counterintuitive decision to apply the finishing coating to the bottom surface and use the finished bottom surface as the visible part of the leather substitute. In other words, the inventors inverted the material and finished only the bottom surface. Means for Solving the Problems

[0007] Thus, the present invention provides a method for manufacturing a finished leather substitute, the method comprising: a) providing a sheet material grown from mycelium, the sheet material showing an upper surface layer and a bottom surface layer defined in terms of the growth of mycelium from bottom to top; b) contacting the sheet material with an aqueous solution containing a lubricant; c) drying it; d) applying at least one finishing coating only to the bottom surface.

[0008] The finishing can be applied in one or more coats, simultaneously or successively.

[0009] Another object of the present invention is a finished leather substitute obtained by the method defined herein.

[0010] Yet another subject of the present invention is the use of the finished leather substitute as a substitute for leather in the fashion, accessory, household goods and other furniture industries.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3A

Figure 3B

Figure 4

Modes for Carrying Out the Invention

[0012] Growth of Mycelium In the process of ingesting nutrients, filamentous fungi grow their bodies as a network in which filamentous cells (called hyphae) extend directly into the food and connect to each other.

[0013] Filamentous fungi have a natural tendency to connect small fragments of branched colony hyphae to assemble and weave bundles or sheets of tissue called mycelium, forming larger overall components.

[0014] The mycelium used in the present invention can be derived from any desired fungal inoculum (i.e., any desired amplifiable colony of a desired fungal strain). For example, the fungal species can be selected from the group consisting of Ascomycetes, Basidiomycetes, Deuteromycetes, Oomycetes, and Zygomycetes, and preferably, can be selected from Polyporales, Ganodermataceae, with preference over Ganoderma lucidum, Ganoderma tsugae, Ganoderma applanatum, Ganoderma resinaceum, Ganoderma oregonense. Other candidates include Trametes versicolor, Trametes pubescens, Schizophyllum commune, and Polyporous squamosus.

[0015] In a preferred embodiment, the mycelium is Ganoderma mycelium.

[0016] The sheet material grown from the mycelium can be obtained using any method known in the art, such as the method described in WO2018014004 (Mycoworks).

[0017] As used herein, the term "sheet" generally refers to a layer of solid material having a generally flat or planar shape and a high ratio of surface area to thickness.

[0018] The first fungal inoculum can be introduced into a nutrient that can include a mixture of discrete particles and nutrients such as lignocellulosic waste within or prior to introduction into the enclosure to provide a uniform distribution of the fungus throughout. The substrate is left to form colonies. An intermediate layer can be established on the open surface of the colonized substrate to control the interaction between the fungal tissue structure that forms and the substrate. In certain examples, cellulose-based materials, such as cotton or rayon, are often used because they are biodegradable and were once an undesirable food source for Ganoderma lucidum, which means they maintain strength throughout the growth process in a way that lignin-containing materials do not. The presence of a uniform intermediate material on the substrate allows for a consistent surface on which the fungal tissue can grow and supports the uniform expansion of the fungal mycelium into the environment. The live fungal mycelium grows from the substrate through the intermediate layer. Refer to Figure 1.

[0019] In certain embodiments, the fungal material can be periodically manipulated to induce growth in a manner that imparts desired characteristics including density, uniformity, and higher strength. The growth of the fungal material can be induced in a predetermined pattern such as, for example, orthogonal structures, grids, and other two-dimensional or three-dimensional structures.

[0020] The fungal tissue can be modified, induced, or manipulated during growth to achieve uniform characteristics across the surface, or to exhibit distinct local properties through the manipulation of the growing tissue or the addition of particles, fibers, meshes, fabrics, and other additives, frameworks, and components.

[0021] The intermediate layer may be detached from the nutrient source on which it grew to terminate further growth of the material, or the fungal tissue layer may be detached from the intermediate layer that remains in place and is optionally reused.

[0022] In certain embodiments, a sheet material grown from mycelium is obtained by a method comprising the following steps. a. providing a nutrient medium; b. Growing fungal tissue from the nutrient medium, wherein the fungal tissue comprises fungal hyphae; c. Extending the growth of the fungal tissue through a porous material that defines an intermediate layer; d. Growing a portion of the fungal tissue that extends away from the nutrient medium and through the porous material into a controllable space, wherein the fungal tissue within the space defines at least one continuous layer of fungal material; e. Inducing a change in the composition or growth pattern of at least one of the fungal hyphae in at least one layer; f. Separating at least a portion of the fungal material from the nutrient medium; g. Modifying the portion of the fungal material by physical or chemical means.

[0023] The intermediate layer typically does not readily bind to the fungal tissue and provides initial conditions for uniform growth, thereby achieving uniform growth of the fungal tissue. The porous material is preferably micro-perforated or woven.

[0024] After the growing fungal tissue has been manipulated to induce a change in its growth pattern, the fungal material can be withdrawn from the intermediate layer, thereby promoting continuous growth of the fungal material.

[0025] In another embodiment, the material obtained by the growth of the mycelium may be a self-standing material such as the material obtained by the method described in U.S. Patent No. 9,485,917 (Ecovative Design).

[0026] In this method, the mycelium grows through the substrate, and the net shape of the substrate is limited by the physical dimensions of the enclosure.

[0027] In the next step, the substrate firmly held together by the mycelial network is separated from the enclosure, and if necessary, the internal enclosure or elements are separated.

[0028] Composite material In certain embodiments, the sheet material grown from the mycelium further comprises another material not grown from the mycelium, optionally embedded within the mycelium.

[0029] The material can be incorporated into the growing fungal tissue while the fungal material is still viable to induce growth and / or produce a composite material. In one embodiment, cellulosic, synthetic or other organic fibers including various fabric forms (e.g., woven, knit, full, felt) of suitable length and structural properties are deposited on the exposed surface of the growing fungal tissue to enable the growth of the composite material. The composition and organization of the composite fibers enable the manipulation of the fungal tissue and enhance the mechanical properties of the overall material, including tensile and compressive strength.

[0030] In another embodiment, the fungal tissue can be grown through 2D and 3D matrices and objects of various materials to create a composite having desired properties and qualities. The layers of this additional material can be composed of any material (pore size greater than 1 micrometer) through which the fungal cells can grow. These layers can be pressed onto or near the surface of the growing cells, or otherwise pressed onto the surface, or placed between two or more layers of the growing fungal material, such that these reinforcing layers are then incorporated into the fungal tissue.

[0031] The material not grown from the mycelium preferably includes cotton, silk, linen, polyester, polyamide, wool, nylon, Dyneema®, cellulose, or any regenerated cellulose fiber (also called "rayon") including viscose, modal, and lyocell (Tencell / Lenzing AG), or any combination thereof.

[0032] Top layer and bottom layer The sheet material grown from the mycelium is typically not uniform and exhibits structural polarity, with the top layer being more hydrophobic than the bottom layer.

[0033] The upper layer can be defined as containing more fungal hyphal tips compared to the bottom layer and / or as the surface that comes into contact with air (or gas) during the growth of the mycelium.

[0034] Generally, the upper layer and the bottom layer are defined in terms of the growth of the mycelium from the bottom to the top.

[0035] The upper layer and the bottom layer exhibit different structural characteristics. The upper layer is typically less porous and more hydrophobic compared to the bottom layer.

[0036] Therefore, it should be understood that the sheet material grown from the mycelium, which is used as the starting material in the present invention, cannot be obtained by a process that includes grinding the mycelium and optionally adding a polymer to convert it into a paste. Such a material does not exhibit structural polarity, and the upper layer is more hydrophobic than the bottom layer.

[0037] Lubrication The method of the present invention includes step b) of bringing the sheet material into contact with an aqueous solution containing a lubricant. This step is also called a lubrication step or a fatliquoring step because it introduces oil into the material.

[0038] This contacting step may include, for example, immersing the material in the solution by placing it in a drum, a washing machine, a stable tub, or other suitable processing means.

[0039] In a preferred embodiment, the aqueous solution containing the lubricant contains a fatliquoring agent and an emulsifier.

[0040] Fatliquors can typically contain various types of oils such as mineral, synthetic, animal, and plant-based oils or combinations and mixtures thereof. Oils based on animal fats can be, for example, fish oil, wool fat, beeswax, or lard oil. Oils based on plant-based fats can be, for example, castor oil, coconut oil, cottonseed oil, olive oil, rapeseed oil, linseed oil. For example, oils based on synthetic oils can be derived from modified or synthetic fatty acids or fatty alcohols or modified vegetable or animal oils. These fatliquors are preferably obtained by sulfation, sulfitation, or formation of sulfonic acids of the above oils so that they are soluble or emulsifiable in water.

[0041] Other plasticizers and wetting agents well known in the art can be used so that the microdroplets of the oil can penetrate the material. Various fatliquors contain emulsified oils in water with the addition of other compounds such as ionic and non-ionic emulsifiers, surfactants, soaps, and sulfates.

[0042] Plasticization and stabilization In a preferred embodiment, step b) of the method further comprises plasticizing and / or stabilizing the sheet. The steps of plasticization and stabilization can be carried out simultaneously with, or subsequent to, lubrication.

[0043] In a preferred embodiment, plasticization and / or stabilization can be carried out by contacting the sheet with at least one polyol and / or a fatty solvent, optionally in combination with at least one polycarboxylic acid.

[0044] Examples of plasticizers include glycerol and its esters, sorbitol, polyethylene glycol, polypropylene glycol, propanediol, citric acid, oleic acid, oleic acid polyol and its esters, epoxidized triglyceride vegetable oils, castor oil, pentaerythritol, fatty acid esters, carboxylic acid ester plasticizers, trimellitic acid esters, adipic acid esters, sebacic acid esters, maleic acid esters, biological plasticizers, and combinations thereof.

[0045] Preferably, the sheet can be contacted with glycerol, preferably in combination with citric acid (preferably in water).

[0046] The agent can be added to a drum or any device into which the material is loaded.

[0047] Massaging the sheet for complete penetration can be further advantageous.

[0048] Tanning and dyeing In a preferred embodiment, step b) of the method further comprises contacting the sheet material with tannins, preferably an aqueous solution containing a lubricant further contains tannins. Preferred tannins are condensed tannins, hydrolysable tannins and / or synthetic tannins.

[0049] As used herein, the term "tannin" generally refers to any molecule that forms a strong bond with protein structures. The most commonly used types of tannins are vegetable tannins, i.e., tannins extracted from trees and plants, and chromium tannins such as chromium(III) sulfate. Other examples of tannins include modified natural-derived polymers, biopolymers, and salts of metals other than chromium, such as aluminum silicate (sodium aluminum silicate, potassium aluminum silicate, etc.) or aluminum such as alun. Synthetic tannins such as those obtained by the condensation of sulfonated aromatic compounds and / or non-sulfonated aromatic compounds with formaldehyde and / or urea can also be used.

[0050] To impart color to the sheet material, various dyes can be used, such as acid dyes, direct dyes, disperse dyes, sulfur dyes, synthetic dyes, reactive dyes, pigments (e.g., iron oxide black, titanium dioxide, and cobalt blue), and natural dyes. In some embodiments, the material is immersed in an alkaline solution to facilitate the uptake and penetration of the dye into the material prior to the application of the dye solution. In some embodiments, the material is pre-soaked in ammonium chloride, ammonium hydroxide, and / or formic acid to facilitate the uptake and penetration of the dye into the material prior to fixing the dye, preferably by lowering the pH, before the application of the dye solution.

[0051] In some embodiments, tannin may be added to the dye solution.

[0052] In various embodiments, the plasticizer is added after or during the addition of the dye. In various embodiments, the plasticizer may be added together with the dye solution.

[0053] In various embodiments, the material can be subjected to mechanical processing or agitation while the dye solution is being applied to facilitate the uptake and penetration of the dye into the material.

[0054] Drying A sheet material moistened with an aqueous solution containing a lubricant and optionally variously treated with a plasticizer and / or a stabilizer, tannin, and / or a dye can then typically be cured, typically by crosslinking, by heating at 50 to 100 °C, preferably 70 to 80 °C, preferably for 10 to 60 minutes.

[0055] The drying step c) of this method then involves leaving the material at room temperature, or in a ventilated oven (about 20 to 40 °C), or in a tanning dryer tunnel for several days.

[0056] In a preferred embodiment, the polymerization between the polycarboxylic acid (e.g., citric acid), polyol (e.g., glycerol) and the mycelial material induces stabilization of the smooth appearance of the surface and strengthening of the whole material. Also, flexibility is maintained after drying.

[0057] Finishing The method of the present invention includes step d) of applying at least one finishing coating on the dried material.

[0058] Surface coating techniques such as pad, spray or roller coating can be used for the finishing process. Preferably, the deposition of this finishing coating is carried out by roller coating so as to lay and compress the mycelial fibers while lining the surface.

[0059] Mechanical processes such as buffing, staking and embossing can also be used as well.

[0060] One or more finishing coating layers can be applied.

[0061] The finishing coating is typically applied by contacting an aqueous solution containing a polymer emulsion, a crosslinking agent, and optionally a pigment and / or a filler on the dry sheet. In a preferred embodiment, several solutions are applied.

[0062] The finishing coating can include at least one monomer and optionally at least one catalyst, and the process further includes the step of polymerizing the monomer. In another embodiment, the finishing coating can include at least one polymer, at least one crosslinking agent, and optionally at least one catalyst, and the method further includes the step of crosslinking the polymer.

[0063] In a preferred embodiment, a first aqueous layer called a primer coat is applied to promote adhesion. The primer can include a dispersion of alcohol and polymer. After drying the primer, a next coat containing an emulsion of some resins and crosslinking agents can be applied. At this stage, a colorant, pigment or filler can be added to this mixture to impart or adjust the color of the final material, i.e., the finished leather substitute. For example, the polymer emulsion can include an emulsion of anionic, cationic or neutral polyurethane or acrylate in an aqueous medium and / or in the presence of a cationic or nonionic anionic surfactant and / or in the presence of an alcoholic organic solvent.

[0064] Finally, one or more layers called top coats are typically applied to protect the material from wear and discoloration and to give the finished leather substitute its final touch and aesthetic. It may be composed of a mixture of polymer, silicone agent and crosslinking agent.

[0065] Optionally, a crosslinking agent, such as polycarbodiimide or polyisocyanate or polyaziridine, can be added to cure the deposited layer and ensure better mechanical resistance.

[0066] Optionally, surface treatment, texturing, polishing steps can be performed to impart texture to the material or smooth the surface.

[0067] In certain embodiments, the finishing step d) can include incorporating fillers of natural origin such as microcrystalline cellulose or cellulose nanofibrils and / or ground shells.

[0068] In another preferred embodiment, the finishing step d) includes applying an emulsion of natural polymers such as casein, albumin or other proteins, or synthetic polymers such as polyurethanes and polyacrylates.

[0069] Typically, 24 hours is advantageous for the finish to stabilize and dry before proceeding to the next step.

[0070] Finished leather substitute The product obtained by the method described herein is a finished leather substitute. It can be used as a substitute for leather in the fashion, accessory, household appliance, and other furniture industries.

[0071] It can be used in particular for the manufacture of bags, shoes, watch straps, belts, wallets, etc.

[0072] The drawings and examples illustrate the invention without limiting the scope of the invention.

[0073] Examples The mycelium sheet material was obtained as described in the international application WO2018014004 (Mycoworks).

[0074] Figures 3A and 3B are SEM images of the top and bottom surfaces respectively, showing differences in structure and porosity. The top surface is less porous, with the mycelium hyphae compressed and fused, while the bottom surface is more porous and less compact. The water droplet absorption time was measured with a contact angle goniometer device. The water droplet absorption times were 27 seconds on the top surface and 1.5 seconds on the bottom surface respectively, and the contact angles at t = 0 seconds were 73° on the top surface and 43° on the bottom surface respectively. These results confirm that water penetrates more easily and the hydrophilicity is higher on the bottom surface compared to the top surface.

[0075] Next, as shown in FIG. 2, the mycelium sheet is subjected to the following treatments. - Immersion: The mycelium sheet is first immersed in an aqueous solution at room temperature under static conditions. - Stabilization / lubrication: Next, the material is stabilized in a drum and fixed under acidic conditions using a bath at 40-60 °C composed of a mixture of water, glycerin, vegetable tanning agent, fatliquor, and dye. - Plasticization: To achieve complete and uniform penetration of this mixture, the material is plasticized by adding glycerol and citric acid to water and massaging at room temperature. - Drying: Thereafter, the material is crosslinked by heating at 50-80 °C for 5-120 minutes and finally dried at 25-40 °C. - Finishing: Next, a finishing coating is applied only to the bottom layer by spraying various aqueous solutions containing a polymer emulsion containing water, a filler (colloidal resin), a polymer, and a wax emulsion, and a softening agent and a wetting agent composed of oil.

[0076] The finished product (see FIG. 4) exhibits excellent properties as a leather substitute, particularly in terms of abrasion resistance and flexibility. It is also not affected by changes in weather or ultraviolet rays.

Claims

1. 1. A method for producing a finished leather substitute, comprising: a) providing a sheet material grown from mycelium, the sheet material exhibiting a top layer and a bottom layer defined in terms of mycelium growth from bottom to top; b) contacting the sheet material with an aqueous solution containing a lubricant; c) drying it; d) applying at least one finish coating only to said bottom surface; A method comprising:

2. 10. The method of claim 1, wherein the finish coating is applied by contacting, e.g., spraying, an aqueous solution containing a polymer emulsion and, optionally, pigments and / or fillers, onto the bottom surface of the dry sheet.

3. 3. The method of claim 1 or 2, wherein step b) further comprises contacting the sheet material with a tannin, preferably wherein the aqueous solution comprising a lubricant further comprises a tannin.

4. 4. The method according to any one of claims 1 to 3, wherein step (b) further comprises a plasticization and / or stabilization step of the sheet, preferably carried out by contacting the preferably tanned sheet with at least one polyol and / or fat solvent, optionally combined with at least one polycarboxylic acid.

5. The method of any one of claims 1 to 4, wherein the finish coating comprises at least one monomer and at least one catalyst, the method further comprising the step of polymerizing the monomer.

6. The method of any one of claims 1 to 5, wherein the finish coating comprises at least one polymer, at least one crosslinking agent, and at least one catalyst, the method further comprising the step of crosslinking the polymer.

7. The method according to any one of claims 1 to 6, wherein the mycelium is Ganoderma lucidum mycelium.

8. A finished leather substitute obtainable by the method according to any one of claims 1 to 7.

9. 9. Use of the finished leather substitute according to claim 8 as a leather substitute in the fashion, accessories, household goods and other furniture industries.

10. Use according to claim 9 for producing bags, shoes, watch straps, belts or wallets.

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