IT202000013387A1 - METHOD OF COATING FUNGAL FELT AND BIOLOGICAL-BASED COMPOSITE MATERIALS OBTAINED FROM THEM - Google Patents

Description

DESCRIPTION

of an application for a PATENT FOR INDUSTRIAL INVENTION with the following title:

"Method of coating fungal felts and bio-based composite materials obtained therefrom".

Technical field

The present application relates to a new family of bio-based composite materials and the method for their manufacture. Pi? in particular, the invention relates to the method for coating fungal felts derived from a homogenized or vital slurry of mushrooms using a bio-based polymeric composition, and to the products obtained therefrom, in particular for application in the market of flexible, such as leather, imitation leather, fabrics, upholstery and textile products.

State of the art

The textile industry ? one of the industries most pollutants in the world and has a substantial impact on the environment.

In recent years, great attention ? been aimed at the development of new sustainable and compostable textile materials obtained with the use of ecological and non-polluting processes.

Pi? Specifically, in the animal-derived products sector, alternatives to the use of animal skin are growing in various markets thanks to the increase in awareness of environmental impact and animal welfare. The production of animal skin raises ethical issues and has a negative impact on the environment due to the use of large quantities of animal skin. of natural resources and toxic chemicals used for leather processing. Several strategies have been proposed to produce animal-free and sustainable leather-like materials. For example, products from waste materials from the production of apple, pineapple or mushroom juice were obtained.

Mushrooms, in particular, are one of the most common living organisms. abundant and more rapid growth of the planet.

The fungal mycelium ? the vegetative structure of mushrooms and ? made up of a network of fine filaments, called hyphae. Hyphae are formed by cells that grow as elongated tubular structures with a diameter of 2-10 ?m and form a dense network of intertwining filaments. Cells are surrounded by the cell wall, which can constitute up to 30% of the dry weight of the cell, and has a composition consisting primarily of ?-type glucans, chitin, and other structural proteins. Due to the high quantities of chitin in the cell walls and its similarity to cellulose in terms of structure, ? It has been suggested that fungal mycelium could find industrial application as an alternative to wood pulp in the paper, biomedical and textile industries.

Fungal Flexible Materials (FFM) are normally made of pure fungal mycelium felts which are used for making flexible products, being a circular and low impact solution with natural colors and malleable surfaces ranging from soft and velvety to cork-like, similar to suede, felt or rubber to the touch. However, the materials do not meet the mechanical performance required for industrial applications by exhibiting low tear strength and high susceptibility to tearing. to abrasion. The production of FFMs ? in fact, a new branch in the field of fungal biotechnology with less than 15 years of activity, but still in its infancy, and consequently these activities? search engines are far from providing ready-to-use results.

Therefore, companies looking to provide functional solutions are implementing more efficient approaches. traditional to improve the physical and mechanical characteristics of the leather-like FFM, mostly? imported directly from the classic leather and textile manufacturing industries.

These methods range from simple techniques applied during the cultivation phase such as the incorporation of reinforcing fibers (e.g. polyester, polyamide, nylon, viscose, cotton, silk, wool, cellulose, etc.) within the fungal matrix of the hyphae growing to form a fungal composite pi? homogeneous and resistant as reported in WO2020006133A1, to surface homogenization methods such as mechanical abrasion and pressure which smooth and improve the microstructure of the mycelium as described in WO2020018963A1, to more chemical treatments? including the deacetylation and crosslinking of chitin and chitosan fractions naturally present in fungal materials with the addition of chitin nanofibers via genipin, so as to impregnate and crosslink the chitin nanofibers within the mycelial matrix improving the overall mechanical strength, a quite promising method as disclosed in WO2019178406A1. On the other hand, the use of organic solvents is more traditional methods such as alcohol and acetic acid, and treatment with salts (calcium chloride), phenols, polyphenols, tannins, waxes, plasticizers (glycerin, sorbitols, etc.) and / or dyes ? been suggested in WO2018183735A1.

Has the Applicant already tackled the problem and filed the international patent application PCT/IB2019/060466 which describes and claims a method for producing a more homogeneous mushroom felt compared to the previously described fungal felts and with multiple advantages in terms of logistics, costs (both capital and operating) and contamination risks. Such fungal felt ? composed of pure fungal biomass or mycelium, other than a composite, and free from incorporated fibers and discrete lignocellulosic particles. In short, a flexible, resistant, homogeneous and aesthetically pleasing mushroom material, which could be used as an alternative to flexible materials.

Considering its biodegradable nature, and despite all the listed benefits and quality? overall top of the fungal felts cos? obtained, in their raw form these mushroom felts are still characterized by a flexibility? relatively poor quality and are still prone to tears and abrasions when used on their own on a daily basis, especially when used as in footwear, upholstery, interior design elements or luggage, and hence, a proper coating becomes necessary to protect the material and enhance the its properties? physical and mechanical properties and to provide a durable and truly functional product. Such application of the coating ? a common treatment in the traditional leather industry, used to enhance and make functional animal skins, which are also extremely weak and fragile in their natural raw state. In fact, many other chemical and mechanical treatments are required for the production of animal hides to improve the performance of the raw hides. Normally, a large variety of colors are sprayed on them. of coating products or mixtures, such as dyes, resins, oils, paraffins, glues and multiple polymers of petrochemical origin.

Composite materials obtained with post-treatment methods such as the coating of dry mycelium felts with a layer of porous material, such as a fabric of natural origin (hemp, cotton or linen) or a synthetic or natural polymer (polyhydroxyalkanoates (PHA), acid polyglycolic acid (PGA), poly-?-caprolatone (PCL), polylactic acid (PLA), cellulose acetate, chitin/chitosan, corn zein and/or starch) are also described in international patent application PCT/IB2019/060466.

Polyvinyl chloride (PVC), polyethylene (PE), polypropylene (PP), polystyrene (PS), and polyurethanes (PU) are petrochemical polymers commonly used in the manufacture of high-strength textile and leather upholstery products. Despite their significant contributions to human well-being and development, most of these compounds considered harmful to the environment and not recyclable in practice, thus accumulating and polluting? landfills and waterways around the world. Among all these, at least polyurethanes are considered to be a digestible material for a variety of products. of microbes, especially for fungi, whose enzymes play a crucial role in the biodegradation of this and other polymeric materials.

Exploring the advantageous characteristics of PU-based materials and the theoretical and promising possibility complete biodegradation in the short term, in recent years researchers have started to develop so-called bio-polyurethanes (Bio-PU), which are PU formulations containing 20% to 90% bio-based ingredients or renewable carbon fractions , composed mostly from polyols and fillers from plant biomass, and therefore increasing its biodegradability? and reducing the impact of carbon production. Bio-polyurethanes have found a wide range of applications in rigid insulations, paints, coatings, adhesives, foams, elastic fibers, flooring, fabrics and footwear.

However, to the applicant's knowledge, there are no specific descriptions of the coating methods, in particular wet coating, of the flexible mycelium felts. Pi? specifically, right? It is possible to find no literature related to the application of PU or bio-PU coating products to fungal biomaterials. Furthermore, one of the main factors limiting the industrial application of mycelium felts is the poor properties? mechanical and superficial, and the attempts to apply the coating made up to now have led to poor results, due to the adhesion limitations generated by the morphology and chemistry of the substrate.

For this reason ? Is there a need for custom lining processing that results in high quality mycelium felts? in terms of high strength, flexibility? and sustainability.

Furthermore, many of the coatings currently used by the traditional leather industry have serious limitations and disadvantages in terms of environmental friendliness. and sustainability overall, so there ? still the need? of better formulations of bio-PU that can be degraded more? efficient by microbes once the life cycle of the material or product is exhausted, implying a neutral or negative carbon impact, and leaving behind? nothing but nutrients for the soil and the biosphere.

Finally, there the need? of a new method that provides fungal felts with properties? improved mechanics and aesthetics.

Summary of the invention

The Applicant has found a new method for use in the coating of bio-manufactured flexible materials, in particular materials of fungal origin, preferably mycelium felts.

In particular, the method provides for the application of a coating composition to pi? components on a surface of a mushroom felt with the aim of improving the tear and tensile strength, the flexibility? and the abrasion resistance of the mushroom felt.

The present invention discloses a coating method, preferably based on spray application and utilizing a bio-based coating formulation, capable of overcoming the current limitations of fungal flexible materials and drastically improving their properties. mechanical and physical.

Consequently, a first aspect of the present invention relates to a method for preparing a flexible composite material comprising the steps of:

1) provide a coating composition comprising a bio-based polymer with a viscosity? between 50 and 2,500 centipoise;

2) to provide a flexible mushroom material with a front (air) side and a back (grainy) side, where the air side is? able to absorb the coating composition;

3) applying the coating composition to the face (aerial) side of the flexible mushroom material to obtain a wet coating layer; and 4) drying the wet coating layer to obtain a flexible composite material comprising a dried coating layer on a flexible mushroom material,

wherein said dried coating layer has a weight of between 0.05 and 3.00% by weight, based on the weight of the uncoated flexible mushroom material.

A second aspect of the present invention relates to a flexible composite material comprising:

(a) a flexible mushroom material comprising at least 90 wt%, preferably at least 95 wt%, and more? preferably at least 98% by weight of pure fungal biomass, based on the total weight of the flexible fungal material, and

(b) a dried coating layer comprising a bio-based polymer,

wherein said dried coating layer has a weight of between 0.05 and 3.00% by weight, based on the weight of the uncoated flexible mushroom material.

A third aspect of the present invention relates to a finished product comprising at least one component made with the flexible composite material according to the second aspect of the present invention.

Description of the Figures

Figure 1 shows the collection of fungus felt obtained in example 2.

Figure 2 shows the PU coated mushroom felt obtained in Example 3.

Definitions

The term "flexible product" as used herein refers to any product made of, or comprising, a soft, pliable material such as fabrics and/or leather. These include clothing, cloth, garments, footwear, headgear, sportswear, backpacks and luggage, bedding, linens, consumer electronic accessories, furniture or automobile upholstery, etc. The term "lignocellulosic material," as used herein, refers to a material that contains cellulose, hemicellulose, and lignin as major components and, optionally, more small of pectin, protein and ash. The relative content of each of these constituents varies according to the origin of the lignocellulosic material.

The term "felt" or "fungal felt", as used herein, refers to a sheet of material formed from interwoven or interconnected fungal hyphae that form a continuous, flat surface. Preferably, said sheet of material ? consisting exclusively of fungal mycelium.

The term "mycelium" as used herein refers to the vegetative body of a filamentous fungus consisting of a mass of branching filaments, called hyphae. The term "filamentous fungus" as used herein refers to any member of the eukaryotic group of organisms, including the ascomycetes and basidiomycetes fungi that form filamentous structures known as hyphae. Hyphae are multicellular structures that are tubular, elongated, and thread-like (filamentous), which can contain multiple? of one nucleus per cell and which grow by branching and extending to their ends.

The term "solid nutrient medium", as used herein, refers to a solid substrate that provides both support and nutrients for the growth of fungal mycelia.

The term "pure culture", as used herein, refers to an axenic culture in which ? present only one strain or clone, in the absence of other organisms or types.

The term "flat container" used in this document ? a container consisting of a flat base surface enclosed by sides.

The terms "viable fungal homogenate", "viable homogenate", "mycelial homogenate", "fungal homogenate", "fungal homogenate" or optionally just "homogenate" as used herein, refer to a fine viscous mixture or dispersion of substrate particles , fluids (i.e. liquids and/or gases) and viable fungal hyphae. The terms "mixing" or "mixing step" as used herein refer to the process of obtaining a viable fungal homogenate starting from a pre-colonized solid substrate and water with mechanical means suitable for obtaining the aforementioned viable fungal homogenate.

Detailed description of the invention

The present invention relates to a method for preparing a flexible composite material comprising the steps of:

1) provide a coating composition comprising a bio-based polymer with a viscosity? between 50 and 2,500 centipoise;

2) to provide a flexible mushroom material with a front (air) side and a back (grainy) side, where the air side is? able to absorb the coating composition;

3) applying the coating composition to the face (aerial) side of the flexible mushroom material to obtain a wet coating layer; and 4) drying the wet coating layer to obtain a flexible composite material comprising a dried coating layer on a flexible mushroom material,

wherein said dried coating layer has a weight of between 0.05 and 3.00% by weight, based on the weight of the uncoated flexible mushroom material.

In a preferred embodiment, the coating composition comprises a bio-based polymer dissolved or dispersed in a carrier.

The support ? preferably selected from the group consisting of water, organic solvents and their mixture.

The organic solvent can be selected from the group consisting of alcohols such as ethanol, diacetone alcohol, isopropanol or n-butanol; ketones, such as acetone, ethers, such as dimethyl ether, diethyl ether; alkanes such as pentane, cyclopentane, hexane, toluene, heptane or cyclohexane; cyclic ethers such as tetrahydrofuran; glycol ethers, such as ethylene glycol acetate monobutyl ether; phenylated solvents such as xylene; esters of acetic acid such as butyl acetate, methyl acetate, pentyl acetate, propyl acetate or ethyl acetate; and a mixture thereof.

The coating composition preferably comprises a carrier in an amount from 10% to 90% by weight, more? preferably from 20 to 80% by weight with respect to the total weight of the coating composition.

The coating composition preferably has a viscosity from 100 to 2,000 centipoises, plus? preferably from 200 to 1,500 centipoise, and more? preferably from 300 to 1,000 centipoise.

In another preferred embodiment, the bio-based polymer is a bio-based polyurethane.

Bio-based polyurethane? a polyurethane obtained by a method comprising a reaction step of a polyol and a polyisocyanate compound, wherein at least one of the polyol and polyisocyanate compounds is derived from biomass resources, the cio? ? a bio-based ingredient.

Preferably, the bio-based polyurethane has a content of bio-based ingredients ranging from 20 to 90% by weight with respect to the total weight of the bio-based polyurethane.

Biomass resources include those in which solar light energy is converted into a form of starch, sugar, cellulose or the like due to plant photosynthesis and stored; animal bodies that grow by eating plant bodies; products prepared from the processing of vegetable bodies or animal bodies; and similar. The vegetable resources are more? preferable as biomass resources. Examples of plant resources are wood, rice straw, chaff, rice bran, old rice, maize, sugar cane, cassava, sago palm, tofu, corn cob, tapioca, bagasse, vegetable oil residues, potatoes, soba, soybeans, fats and oils, waste paper, papermaking residues, aquatic residues, livestock droppings, sewage sludge, food waste, and the like.

Useful examples of bio-based polyurethane and related production methods are known in the art, as described, for example, in WO2018220983A1 and EP2554559. A large number of vegetable oil derivatives such as castor, soybean, sunflower, olive, peanut, canola, corn, and safflower, among others, are used as naturally obtained bioresources to produce a large variety of vegetable oils. of bio-based polyurethanes with different structures and chemical compositions.

Biomass resources can also include mushrooms. Advantageously, the bio-based content such as mushroom-based ingredient could vary from 1 to 30% by weight with respect to the total weight of the bio-based polyurethane. The mushroom ingredients are preferably selected from the group consisting of mushroom polyols, or fillers such as chitin and/or glucan.

According to a further embodiment, the coating composition can further include cross-linking agents and additives selected from the group consisting of suspending or dispersing agents, surfactants, defoamers, anti-gelling agents, antioxidants, thickeners, moisturizers, stabilizers, strengtheners, plasticizers, flame retardants, pigments, fillers, shimmers and perfumes.

Advantageously, the flexible mushroom material is obtained according to a method as described in PCT/IB2019/060466 which includes the steps of:

a) inoculating and culturing a filamentous fungal species on a solid nutrient medium comprising a lignocellulosic material, thus obtaining a solid nutrient medium colonized by said fungus;

b) mixing said colonized nutrient medium with water or with an aqueous solution and homogenizing to obtain a uniform homogenate;

c) pour the homogenised product into a flat mould;

d) incubate the homogenised product until obtaining a continuous fungal mat of thickness and density? desired;

e) collect the mushroom felt cos? obtained; and optionally

f) wash the collected fungal felt.

In the method of the invention can? any species of filamentous fungi can be used. However, fungal species belonging to the basidiomycotic divisions are particularly preferred. Preferably, said fungal species are selected from Ganoderma, Trameti, Fomi, Fomitopsis, Phellinus, Perenniporia, Pycnoporus, Tyromyces, Macrohyporia, Bjerkandera, Cerrena and Schizophyllum. In the method described here ? it is also possible to use other species belonging to the genera Fusarium, Rhizopus, Aspergillus, Myxotrichum and Trichoderma. The particularly preferred species of mushrooms due to the characteristics of the final felt obtained are Ganoderma spp., Fomes spp., Pycnoporus spp. and Perenniporia spp.

According to a preferred embodiment, a pure culture of a filamentous fungus is inoculated in step a). Alternatively, can you? use a combination of different mushroom species or strains.

According to a preferred embodiment, said solid nutrient medium of step a) consists of at least 90%, preferably 95%, plus? preferably 98%, even more? preferably 100% of its total weight of lignocellulosic material. The lignocellulosic material can can also be chemically treated to improve its consistency, pH and properties? nutrients, for example by adding calcium sulphate, calcium carbonate or other similar mineral additions or mixed with seeds, seed flour or starch powder.

Accordingly, in an alternative preferred embodiment, said solid nutrient medium comprises as a main component, preferably consisting of lignocellulosic material mixed with seeds, seed flour, powdered starch and/or minerals. Preferably, said solid nutrient medium of step a) consists of at least 90%, preferably 95%, plus? preferably 98%, even more? preferably 100% by its total weight of lignocellulosic material mixed with seeds, seed meal, powdered starch, and/or minerals.

Preferably, said seeds are whole seeds selected from whole seeds of millet, rye, sorghum, rice, wheat, corn. Preferably said seed flour is obtained from whole seeds of millet, rye, sorghum, wheat, rice, corn. Preferably said minerals are selected from calcium sulphate and calcium carbonate.

Preferably, the lignocellulosic material to be used in the method of the invention ? selected from agro-industrial lignocellulosic biomass, consisting for example of residues of agricultural crops, energy crops or crops for agricultural purposes, non-agricultural by-products from forestry, paper, food and biofuel industries, or a combination of these.

The solid nutrient medium is selected based on the metabolic needs of the specific fungus being used. For example, Basidiomycete species belonging to the order Poliporales will require more content. high in lignocellulosic materials such as wood and straw, while other fungi belonging to other divisions, may require the presence of a percentage of readily available carbohydrates, such as those present in wheat bran and flour. In phase b), said colonized solid nutrient medium is mixed with water or with an aqueous solution, preferably sterile or sanitized, and then mixed to obtain a homogeneous, viscous and living fungal homogenized product, with properties physical properties that are placed between those of a liquid and those of a solid, resulting similar to the gel state. Preferably, the colonized medium and water or aqueous solution are mixed in a ratio of between 0.5 and 3 g, plus? preferably 2 g of colonized medium for every 10 ml of water.

The mixture is chopped and mixed in a high-speed mechanical mixer, suitable for the quantity? of processed material, for at least 30 seconds, preferably for at least three minutes, and more? preferably for at least five minutes, until a viable fungal homogenate is obtained.

According to a preferred embodiment, the mixture is mixed in a high speed mechanical mixer. at a speed of at least 10,000 rpm, preferably at least 15,000 rpm, and more? preferably at least 20,000 rpm. Preferably, the mixture is blended in a high speed mechanical mixer. at a speed not higher than 80,000 rpm, preferably not higher than 70,000 rpm, and more? preferably not exceeding 60,000 rpm. In one particular embodiment, the blend is blended in a high-speed mechanical mixer. at a speed from 30,000 to 50,000 rpm.

Preferably, the viable fungal homogenate obtained in point b) has a viscosity from 1,000 to 40,000 cps, preferably from 4,000 to 30,000 cps, and more? preferably from 10,000 to 20,000 cps.

In step c), the viable fungal homogenate is poured into a flat container of the desired shape and size. Preferably, the viable fungal homogenate is added in an amount such as to completely cover the internal flat base surface of the container. Preferably, the layer of viable fungal homogenate covering the internal flat base surface of the container has a thickness of from 0.2 to 5 cm, preferably from 0.5 to 1.5 cm to avoid compaction and therefore anaerobic suffocation of the hyphae .

The incubation step d) is carried out by keeping the container horizontal, in static and aerobic conditions at a constant temperature. Preferably, the container ? covered with a lid equipped with a system that allows a controlled exchange of gases between the internal volume of the container and the external environment. Depending on the fungal species and the desired growth conditions, a constant CO2 concentration is maintained, preferably between 2000 - 2500 ppm, by monitoring the CO<2 > concentration in the incubation vessels by means of electronic sensors.

The incubation is carried out until a continuous mycelial mat of the density is formed. and of the desired thickness on top of the homogenised product. There? preferably requires that the incubation be carried out for a period between 8 and 20 days, plus? preferably between 10 and 18 days, even more? preferably 15 days. Incubation times pi? long produce, in general, felts pi? thick and resistant.

Once the felt has reached the thickness and density? desired, is collected as shown in Figure 1. Advantageously, the desired thickness ranges from 0.1 to 6.0 mm, preferably from 0.2 to 5.0 mm, and more? preferably from 0.3 to 4.0 mm. In particular, the density desired ? between 0.1 and 2.0 g/cm<3>, preferably between 0.3 and 1.7 g/cm<3>, and more? preferably from 0.5 to 1.4 g/cm<3>.

Preferably, the fungal thatch of step e) is collected by separating it from the digested effluents below. Pi? preferably, the collection is carried out by collecting the fungal felt from the container leaving behind? the effluents or the undigested fraction of the homogenate.

Preferably, the flexible mushroom material has a tensile strength of 0.5 to 5.0 MPa, measured according to the ISO 3376:2011 method.

Further details are contained in the international patent application PCT/IB2019/060466, the description of which? incorporated herein in its entirety.

The flexible fungal material collected in step e) shows anterior and posterior sides. The front side, also called the air side, is the side in contact with the atmosphere during the incubation phase d). The back side, also called the grainy side, is the side in contact with the homogenate during the incubation phase d).

The flexible mushroom material comprises at least 90 wt%, preferably at least 95 wt%, and more? preferably at least 98% by weight of pure fungal biomass, based on the total weight of the flexible fungal material. Advantageously, the flexible fungal material comprises 100% by weight of pure fungal biomass, with respect to the total weight of the flexible fungal material, i.e. ? totally composed of pure fungal biomass.

According to a preferred embodiment, the flexible mushroom material can be pressed before the step (3) of applying the coating composition to facilitate the formation of a homogeneous coating layer. The optional pressing phase can? be performed in a mechanical or hydraulic press at a pressure between 1.2 bar and 8 bar, more? preferable between 2.0 bar and 5.0 bar. Advantageously, the pressing phase can be conducted at a temperature between 20? and 80?C, preferably between 40? and 60?C.

The coating phase (3) can? be performed by various techniques known in the art, such as spray coating, knife coating, curtain coating, dip coating and the like. Preferably, the coating step (3) is carried out both by spraying and by spraying, preferably by spraying with any type of spray gun or spray machine known to the person skilled in the art to be suitable. purpose.

Typically a system of this type comprises at least one air distribution channel for nebulized air, at least one channel for ventilation air, at least one nozzle for spraying the fluid and at least one channel for the reagents. The coating composition, containing the carrier and the coating formulation, is sprayed through the nozzle, using the venturi effect generated in the spraying machine.

The advantage of spray application? the capacity? to efficiently deposit a quantity? of coating from 5 to 70 g/m<2 >, preferably from 10 to 50 g/m?.

An additional benefit of spray application ? the capacity? to fill in a homogeneous way the porosity? of the material surface.

In one embodiment, the coating composition is applied to the surface of the mycelium during incubation step d) described above.

In another embodiment, the coating composition is applied to the mycelium surface after the harvesting step e) described above.

In a further embodiment, the coating composition is applied to the mycelium surface in two or more layers. consecutive passes. Typically, a base and top coat that differ in composition and properties are applied synergistically. The base coat? a PU used as an adhesive, the cio? a PU coating which is sprayed directly onto the raw surface of the FFM to ensure adhesion between the FFM and the subsequent coating layer, such as a top coat or other coating layers. Common characteristics of PU base coat are the ability to to penetrate the substrate or FFM, the high stretch and flexibility. Such PU base coats are usually made with polyether or polyester polyols and polyisocyanates, as well as solvent or water.

The top coat has higher performance than the base coat because it is ? made of polycarbonate or polyester/polycarbonate blends of polyols and aliphatic polyisocyanate. A cross-linking agent is added into the top coat formulation before use, ie? to give the dried PU a branched microstructure. The final cured coating will show? property? more mechanical high resistance to solvents, scratches, UV rays and atmospheric agents.

To avoid pinholes, foaming or irregularities, or to improve slipperiness? of the top coat, processing aids (e.g. leveling agent, matting agent, hand modifier, defoamer) are mixed with the coating composition prior to application.

The drying step (4) provides for the evaporation of the support and the formation of the dried coating layer. Each wet coating layer is dried at least until the adhesive effect is removed.

The support can be made to evaporate at a temperature ranging from 20?C to 250?C, more? preferably between 50?C and 150?C. Within this range, the support can? be evaporated at a constant temperature or by varying the temperature over time.

Advantageously, the dried coating layer has a final coating weight of 1 to 40 g/m<2>, preferably 5 to 30 g/m<2>, and more? preferably from 10 to 20 g/m<2>.

The present invention also relates to a flexible composite material comprising:

(a) a flexible mushroom material comprising at least 90 wt%, preferably at least 95 wt%, and more? preferably at least 98% by weight of pure fungal biomass, based on the total weight of the flexible fungal material, and

(b) a dried coating layer comprising a bio-based polymer,

wherein said dried coating layer has a weight of between 0.05 and 3.00% by weight, based on the weight of the uncoated flexible mushroom material.

The dried coating layer comprising a bio-based polymer is preferably obtained according to steps (3) and (4) of the method of the present invention, as described above.

In a first preferred embodiment, the flexible composite material has a tensile strength of 8.0 to 50.0 Mpa, measured according to the ISO 3376:2011 method.

In a second preferred embodiment, the flexible composite material has a flexural strength of 1,000 to 50,000 cycles, measured according to the ISO 5402 method under dry conditions.

In a third preferred embodiment, the flexible composite material has an abrasion resistance of 1,000 to 60,000 cycles, measured according to the ISO 17076 method under dry conditions.

The flexible mushroom material ? obtained according to a method described above and in PCT/IB2019/060466.

The dried coating layer has a thickness of 0.001 to 2,000 mm. The dried coating layer can be a thin layer with a thickness of less than 0.500 mm, preferably between 0.0100 and 0.200 mm, or a thick layer with a thickness greater than 0.500 mm, preferably between 0.700 and 2,000 mm, more preferably between 1,000 and 1,500 mm.

A third aspect of the present invention relates to a finished product comprising at least one component made with the flexible composite material according to the second aspect of the present invention.

In a preferred embodiment, the finished product is an item of (i) clothing, such as a suit, suit, jacket, coat; (ii) clothing accessories, such as a hat, belt, wallet; (iii) footwear, such as, for example, men's and women's shoes, trainers, sandals, moccasins; (iv) upholstery; (v) luggage, such as, for example, a suitcase, briefcase, backpack, purse; or (vi) furniture, such as, for example, sofa, armchair, chair, ottoman, deck chair.

The present invention will be further illustrated hereinafter through a number of preparatory examples, which are provided for indicative purposes only and without any limitation of the scope of the invention as defined in the appended claims.

EXAMPLES

Example 1

Preparation of the topcoat composition comprising a water-based biobased polymer

The reaction ? was performed in a 250 mL four-necked round bottom flask with a mechanical shaker. Firstly, to the ball ? A mixture of a bio-based polycarbonate polyol, dimethyl propionic acid and bio-based chain propagators was added, followed by a water removal at 100°C. The reaction mixture? been then cooled and subsequently ? N-methyl-2-pyrrolidone was added. Subsequently, bio-based isocyanate and organic solvent were added to the mixture and then heated at 80°C for 4 hours. Following the previous steps, ? water was added to the mixture under vigorous stirring (about 2000 rpm) for 10 min. Finally, the organic solvent ? was removed from the dispersion under reduced pressure at 45°C, resulting in a water-based bio-based polyurethane (bio-WPU) emulsion with a solids content of about 13 wt%.

Example 2

Preparation of flexible fungal material

A flexible mushroom material? was prepared according to example 1 of the previous international patent application PCT/IB2019/060466.

A pure culture of the mushroom Ganoderma lucidum preserved in a tube of Potato Dextrose Agar (PDA) ? was inoculated onto several Petri dishes of Malt Extract Agar (MEA) and these were incubated for 5 days at 28°C to create a biomass reservoir which could be stored for at least one week under refrigeration.

Viable, luxuriant and homogeneous portions of mycelia grown on Petri dishes were selected and, under clean air flow, were transferred with a sterile scalpel into different growth flasks containing Malt Yeast Extract Broth (MYEB) liquid growth medium, incubated for 3 days in an incubator at 28°C and 200 rpm. These liquid cultures were inoculated into 3.2 kg bags of pasteurized solid substrate (72 °C for 1.5 hours) containing a 50/50 mixture of hemp chips (800g) and soy husk (800g) with a water content by 50% (1600mL H2O). After 7 days of incubation at room temperature (about 23°C) the colonized substrates were manually separated into small pieces and mixed with water, in a proportion of 600 g of colonized substrate per 3000 ml of water, and mixed mechanically using a mixer 4L sterile laboratory bottle (autoclaved at 121?C for 30 min.) to obtain a homogenate or viable mix containing mycelia and culture medium. The homogenized or mycelium mixture? been poured into flat molds of 55x55cm dimensions and then incubated in static conditions at room temperature for two weeks until a homogeneous and continuous fungal mat was formed which ? manually recovered from the spent liquid effluent.

The mushroom felt obtained ? been removed from the effluent of the spent dough as seen in Figure 1, manually washed with cold tap water and dried with a heated vacuum table.

Example 3

Coating of the flexible mushroom material obtained in Example 2.

Spray application of the base coat ? was carried out with Langro's Telaflex U420 with 20% by weight of dry matter. To the mixture not ? No additional leveling agent has been added.

Teleflex U420 ? a water-based dispersion of PU, obtained from the reaction between a polyol and an aliphatic isocyanate. The film formed by the coalescence of the PU dispersion and by the evaporation of the solvent? elastic and flexible, especially suitable for an adhesive application.

The pigments were added to the base coat resin and mixed gently to avoid incorporation of air bubbles. The wording? was then poured into the container of the gun and sprayed on the flexible mushroom material obtained in example 2. The material sprayed? was then dried for 5 minutes at 120°C in a fan oven. The final weight of the base coat ? state of 8 - 10 g/m?.

Subsequently ? A bio-WPU resin containing 13 wt% dry matter was applied as the top coating layer. The synthesis of this bio-WPU formulation? explained in example 1. It is an aliphatic PU dispersed in water.

The top coat? been mixed with other ingredients before application, in particular a reinforcer, pigments and an isocyanate cross-linking agent (at 2% of the dispersion weight) were added to the bio-WPU resin. After mixing, the material ? been loaded into the gun and then sprayed onto the dry base coat. The top coat layer? was then cured for 7 minutes at 120?C. The final coat weight of the top coat was 4 - 6 g/m2. The resulting flexible composite material ? shown in Figure 2.

Example 4

Preparation of a water-based bio-based polyurethane containing polyols of fungal origin.

The reaction ? was performed in a 4-necked 500 mL reaction flask coupled with a mechanical stirrer, a temperature probe, a nitrogen gas inlet and a cooling tube. The following compounds were added to the flask: dimethyl propionic acid (DMPA), a polyol of fungal origin, a vegetable polycarbonate polyol, dibutyltin dilaurate catalyst (0.01 wt% of the prepolymer), N-Methyl-2-Pyrrolidone (NMP ) (4 wt% of the final WPU) and dry acetone (25 wt% of the prepolymer). Subsequently the compounds were mixed under continuous stirring (500-1000 rpm) at 50??0.5?C, until total dissolution of the DMPA. The mixture ? been heated up to 60??2.0?C under reflux conditions and isophorone diisocyanate (IPDI) ? was added slowly from a pressure funnel (Lenz?) over a period of 30 min. After the addition of the IPDI, the temperature of the reaction mixture ? been raised to 50??2,0? C and mixed at 800-1200 rpm for 3 hours. Then the mixture? been cooled to 40? C and ? was added a quantity? calculated amount of neutralizer (triethylamine) and mixed at 1000-1500 rpm for 20 minutes until a neutralization degree of 85-90% is reached. Subsequently, the reaction mixture ? was brought to 25??2.0?C and transferred to a high speed disc mixer? at 10,000-15,000 rpm (PerMix?), where ? deionized (DI) water containing bio-based chain propagators was slowly added over a period of 10 minutes over the impeller blades. After adding deionized (DI) water, the mixture is ? was continuously stirred at 1500rpm for 30 minutes and then poured into a 5L vacuum rotary evaporator (Rotavapor?) to remove organic solvent under vacuum at 45??2.0?C. Finally, the resulting WPU bio-emulsion ? was cooled to 25??2.0?C and collected in a Pyrex? beaker, with a solids content of about 16 wt%.

Claims (11)

1. A method for preparing a flexible composite material comprising the steps of: 1) provide a coating composition comprising a bio-based polymer with a viscosity? between 50 and 2,500 centipoise; 2) to provide a flexible mushroom material with a front (air) side and a back (grainy) side, where the air side is? able to absorb the coating composition; 3) applying the coating composition to the face (aerial) side of the flexible mushroom material to obtain a wet coating layer; and 4) drying the wet coating layer to obtain a flexible composite material comprising a dried coating layer on a flexible mushroom material, wherein said dried coating layer has a weight of between 0.05 and 3.00% by weight, based on the weight of the uncoated flexible mushroom material. The method according to claim 1, wherein said coating composition comprises a bio-based polymer dissolved or dispersed in a carrier. 3. The method according to claim 2, wherein said coating composition comprises said support in an amount of 10% to 90% by weight, preferably 20 to 80% by weight based on the total weight of said coating composition. 4. The method according to any one of claims 1 to 3, wherein said coating composition has a high viscosity? from 100 to 2,000 centipoise, preferably from 200 to 1,500 centipoise, and more? preferably from 300 to 1,000 centipoise. 5. The method according to any one of claims 1 to 4, wherein said bio-based polymer is a bio-based polyurethane. 6. The method according to claim 5, wherein said bio-based polyurethane has a content of bio-based ingredients ranging from 20 to 90% by weight with respect to the total weight of said bio-based polyurethane. The method according to any one of claims 1 to 6, wherein said flexible mushroom material comprises at least 90 wt%, preferably at least 95 wt%, and more? preferably at least 98% by weight of pure fungal biomass, based on the total weight of the flexible fungal material. 8. A flexible composite material comprising: (a) a flexible mushroom material comprising at least 90 wt%, preferably at least 95 wt%, and more? preferably at least 98% by weight of pure fungal biomass, based on the total weight of the flexible fungal material, and (b) a dried coating layer comprising a bio-based polymer, wherein said dried coating layer has a weight of 0.05 to 3.00% by weight, based on the weight of the uncoated flexible mushroom material. The flexible composite material according to claim 8, wherein said dried coating layer has a thickness of from 0.001 to 2,000 mm, preferably selected from the group of (i) a thin layer with a thickness of less than 0.500 mm, preferably between 0 .0100 and 0.200 mm, and (ii) a thick layer with a thickness greater than 0.500 mm, preferably between 0.700 and 2,000 mm, plus? preferably from 1,000 to 1,500 mm. 10. A finished product comprising at least one component made of the flexible composite material according to claim 8. 11. The finished product according to claim 10, wherein said finished product is an item of (i) clothing, such as a suit, suit, jacket, coat; (ii) clothing accessories, such as a hat, belt, wallet; (iii) footwear, such as, for example, men's and women's shoes, trainers, sandals, moccasins; (iv) upholstery; (v) luggage, such as, for example, a suitcase, briefcase, backpack, purse; or (vi) furniture, such as, for example, sofa, armchair, chair, ottoman, deck chair.