METHOD FOR MANUFACTURING A PART BASED ON LIGNOCELLULOSIC MATERIALS AND MYCELIUM

Abstract

METHOD FOR MANUFACTURING A PART BASED ON LIGNOCELLULOSIC MATERIALS AND MYCELIUM The invention relates to a method for manufacturing a part based on at least one lignocellulosic material and mycelium, in which: - an initial composition is prepared comprising at least one lignocellulosic material in divided form, water, and at least one mycelium precursor; - said initial composition is placed on a predetermined support covered with a protective wrapping for a period of between 24 and 96 hours; - said pre-part is cut, said pre-part having a moisture content greater than 40%; - the part (4) obtained at the end of said fourth step is covered with a protective wrapping for a period of between 24 and 96 hours; - said part is dried. Figure for the abstract: Figure 4

Description

Title of the invention: METHOD FOR MANUFACTURING A PART BASED ON LIGNOCELLULOSIC MATERIALS AND MYCELIUM Technical field of the invention

[0001] The invention relates to a method for manufacturing a part based on lignocellulosic materials and mycelium. Technological background

[0002] Synthetic foams or cellular polymer materials used, for example, in furniture or as wedges in the packaging field are manufactured by molding directly into a desired shape and dimensions or cut from plates or blocks.

[0003] For several years now, there has been a growing interest in plant-based materials capable of replacing synthetic plastics. The use of these plant-based materials is currently limited to molding. This presents a limitation for obtaining certain geometries as well as a barrier to achieving industrial profitability criteria.

[0004] At the geometric level, molding imposes shapes with draft angles of up to 3 degrees, which can be detrimental to the design and optimization of the part or the timing.

[0005] For example, a method is known for manufacturing materials by seeding plant fibers such as sawdust or straw with fungi whose filaments, called hyphae, form the mycelium. However, the known methods do not allow sufficient quality to be achieved, particularly with regard to the surface appearance of the manufactured parts, to enable the production of parts capable of replacing certain parts made of polymer materials of synthetic origin. Furthermore, the cutting of mycelium-based materials is particularly delicate, produces dust and limits the production of parts with particular or complex shapes. Objectives of the invention

[0006] The invention aims to provide a method for manufacturing a part based on lignocellulosic materials and mycelium compatible with industrial constraints.

[0007] The invention also aims to provide, in at least one embodiment, a method for manufacturing a part based on lignocellulosic materials and mycelium, the implementation of which is easy and reliable. Statement of the invention

[0008] To do this, the invention relates to a method for manufacturing a part based on at least one lignocellulosic material and mycelium in which:

[0009] - in a first step, an initial composition is prepared comprising at least a lignocellulosic material in divided form, water and at least one mycelium precursor,

[0010] - in a second step, said initial composition is placed on a pre-prepared support determined and said starting composition is covered with a protective envelope for a period of between 24 hours and 96 hours, a pre-part being obtained at the end of said second step,

[0011] - in a third step, said protective envelope is removed and said pre-room,

[0012] - in a fourth step, a cut is made of said pre-piece so as to obtaining said part, said pre-part having a humidity level greater than 40%,

[0013] - in a fifth step, the part obtained at the end of said fourth stage of a protective envelope for a period of between 24 hours and 96 hours,

[0014] - in a sixth step, the part obtained at the end of said fifth step is subjected step to drying outside said protective envelope.

[0015] Such a method comprising cutting the part before the end of the culture or growth of the mycelium, i.e. before the development of the external surface of the part (called "finishing skin") makes it possible to obtain, not only, a part of the exact desired shape, but also a part whose external surface is relatively smooth, homogeneous and has optimal aesthetic qualities.

[0016] Thus and according to the invention, said mycelium precursor is chosen from the group formed by fungi, and more particularly from the group formed by fungal spores. With regard to the mycelium, it designates the fungus or bacterium with which said lignocellulosic material is inoculated. Thus, advantageously and according to the invention, each mycelium precursor is chosen from the group formed by basidiomycetes, for example of the genus Pleurotus.

[0017] Thus and according to the invention, an initial composition is prepared such that it comprises at least 95% by mass, in particular at least 97% by mass of said lignocellulosic material in divided form and of water relative to the total mass of said initial composition. Indeed, a very small proportion of mycelium precursor is sufficient to allow its development. Furthermore, according to the invention, said initial composition comprises at least 50% by total mass of water relative to the total mass of said initial composition.

[0018] In particular, the initial composition is at least partially mixed during said first step (or even at the start of said second step).

[0019] Thus and according to the invention, said lignocellulosic material in divided form has at least one dimension less than 1.50 cm.

[0020] In particular, each lignocellulosic material is in the form of particles, fibers, granules, chips or even threads. Thus, advantageously and according to the invention, each lignocellulosic material is chosen from the group formed of lignocellulosic materials in divided form, such as lignocellulosic materials in the form of particles, fibers, granules, chips or even threads.

[0021] Thus and according to the invention, said lignocellulosic material in divided form is chosen from the group consisting of wood, grasses, herbaceous plants, straw, hemp, cotton, cereals, climbing plants, flowering plants, shrubs, bushes, fruit trees and mixtures thereof. According to the invention, said lignocellulosic material in divided form has a moisture content of less than or equal to 12%.

[0022] Thus and according to the invention, said second step and said fifth step are each carried out at a temperature between 18°C ​​and 30°C.

[0023] Thus and according to the invention, said support comprises at least one mold. In particular, said support is a mold. It makes it possible to contain the initial composition and to confer at least in part a predetermined shape to the pre-part. It may for example be a mold in the form of a flat-bottomed tray. It may also be a mold having at least one concave portion, for example a mold having a plurality of cavities and from which each molded portion having taken the form of a cavity can be cut out.

[0024] Thus and according to the invention, the protective envelope may be a flexible film made of polymer material or a rigid cover. The protective envelope used during the fifth step may be identical or different from that used during the second step.

[0025] Thus and according to the invention, said fourth step of cutting said pre-piece is carried out by at least one technique chosen from the group formed by water jet cutting, laser cutting and cutting by a cutting and / or vibrating tool (blade or rotary type for example).

[0026] Thus and according to the invention, said drying is carried out during said sixth step at a temperature between 5°C and 80°C, and in particular at a temperature between 50°C and 75°C.

[0027] Thus and according to the invention, said drying is carried out during said sixth step for a period of between 6 hours and 72 hours, and in particular for a period of between 12 hours and 36 hours.

[0028] A method according to the invention makes it possible to obtain parts having an interesting mechanical resistance with regard to its very low mass, that is to say of which the material which constitutes it has a reduced volume mass, in particular a density between 70 kg / m3 and 160 kg / m3.

[0029] The invention also relates to a manufacturing method and a part obtained by such a method characterized in combination by all or part of the characteristics mentioned above or below. List of figures

[0030] Other aims, characteristics and advantages of the invention will appear on reading the following description given solely for non-limiting purposes and which refers to the appended figures in which: • [Fig. 1] is a diagram illustrating a method according to the invention, • [Fig.2] is a schematic view illustrating a second step of a method according to the invention, • [Fig.3] is a schematic view illustrating a third step of a method according to the invention, • [Fig.4] is a schematic view illustrating a fourth step of a method according to the invention, • [Fig.5] is a schematic view illustrating a fifth step of a method according to the invention, • [Fig.6] is a schematic view of a part obtained by a process according to the invention, at the end of a sixth step.

[0031] Detailed description of an embodiment of the invention

[0032] In the figures, the scales and proportions are not strictly respected, for the purposes of illustration and clarity.

[0033] Identical, similar or analogous elements are designated by the same references in all the figures.

[0034] [Fig.l] illustrates the steps of a method according to the invention. It is a method for manufacturing a part based on at least one lignocellulosic material and mycelium and comprising the following six steps.

[0035] In a first step E1, an initial composition 2 is prepared comprising at least one lignocellulosic material in divided form, water and at least one mycelium precursor. By mixing the entire initial composition, at least partial distribution of the mycelium precursor within the mixture of water and lignocellulosic material is ensured. Any type of mixer suitable for mixing a divided solid may be suitable. The initial composition comprises at least 95%, in particular at least 97% by mass of the lignocellulosic material in divided form and water relative to the total mass of the initial composition. In particular, the initial composition 2 comprises at least 40% by mass of lignocellulosic material in divided form and at least 30% by mass of water (added) relative to the total mass of the initial composition.

[0036] The mycelium precursor is chosen from the group formed by fungal spores, in particular from the group formed by basidiomycetes, for example of the genus Pleurotus. Several species of fungi can be used in the same initial composition in equal or different proportions.

[0037] Each lignocellulosic material has at least one dimension less than 1.50 cm and can, for example, be in the form of particles, fibers, granules, chips or even threads.

[0038] Many plants or materials of natural origin can be used. These may, for example, be wood, grasses (stems in particular), herbaceous plants (stems in particular), straw, hemp, cotton, cereals, climbing plants (vines for example), flowering plants, shrubs, bushes or even fruit trees (wood, branches or leaves in particular). The lignocellulosic material in divided form has a moisture content of less than or equal to 12%. The wet lignocellulosic material serves as a nutrient support for the mycelium (or "mycelium spawn").

[0039] In a second step E2, the initial composition 2 thus prepared in step E1 is placed on a predetermined support 10, 12 and covered with a protective envelope 14 for a period of between 24 hours and 96 hours, for example at a temperature of between 18°C ​​and 30°C. At the end of step E2, a pre-piece 4 is obtained. The support used in the embodiment shown in the figures is formed from a mold or tray 10 with a rectangular flat bottom resting on a flat surface 12. The pre-piece 4 obtained after being removed from the tray 10 and shown in FIGS. 2 to 4 is a parallelepiped plate (or a panel). The protective envelope 14 may be a flexible film made of polymer material or a rigid cover. It is not necessary, nor desirable, to form a sealed enclosure around the initial composition 2 and the support 10, 12 during this second step E2.However, such a protective envelope 14 makes it possible to limit the circulation of air in contact with the initial composition 2 by maintaining the humidity present within the initial composition in particular. The protective envelope 14 also contributes to reducing the risk of contamination of the initial composition 2 by bacteria whose presence would possibly be harmful to the growth of the mycelium.

[0040] It is also possible to directly prepare a part of the desired shape using a mold of predetermined shape, for example a mold having a plurality of cavities allowing a plurality of parts to be prepared simultaneously by then cutting out the pre-part at the junctions between these cavities.

[0041] At the end of this second step E2, we therefore obtain a solid pre-part 4, that is to say a part formed from a single piece (manipulable), unlike the com- initial position.

[0042] In a third step E3, illustrated in [Fig.3], the protective envelope 14 is removed and the pre-piece 4 is recovered by removing it from the tank 10. The pre-piece is thus removed from the conditions which allowed the growth of the mycelium, with a view to being cut.

[0043] In a fourth step E4, illustrated in [Fig. 4], the pre-part 4 is cut so as to obtain the desired shape and dimensions of the part that it is desired to prepare, the pre-part 4 having a humidity level greater than 40%. Different cutting techniques can be used, in particular water jet cutting, laser cutting and cutting by a cutting and / or vibrating tool (blade or rotary type for example). In [Fig. 4], a water jet cutting device 25 26 can be seen following a cutting line 6 on the pre-part 4 in order to cut an L-shaped part. A water jet cutting machine marketed by the company OMAX® (HYPERTHERM ASSOCIATES®, USA) can for example be used. In particular, a water jet (without abrasive) can be used, for example a water jet with a diameter between 0.10 mm and 0.30 mm and a cutting pressure between 300 MPa (3000 bars) and 450 MPa (4500 bars).Furthermore, if an abrasive is used in the water jet, it can for example be used with a flow rate less than or equal to 0.100 kg per minute.

[0044] In particular, the fourth step is carried out almost immediately after the third step.

[0045] In a fifth step E5, illustrated in [Fig. 5], the part 30 obtained at the end of the fourth step is again covered with a protective envelope 14 for a period of between 24 hours and 96 hours. During this fifth step E5, the temperature is between 18°C ​​and 30°C, for example 22°C. As can be seen in [Fig. 5], which illustrates the start of this fifth step, the L-shaped part 30 has an upper face 7 which has not been subjected to cutting and whose appearance is already qualitatively correct, that is to say substantially continuous and smooth (without excluding the presence of certain hollows or reliefs due in particular to the shape and size of the lignocellulosic material in divided form used). On the contrary, it can be seen that the edge 9 of the part 30 obtained at the end of the cutting step E4 is rougher.The fifth step E5 will thus make it possible to remedy this defect by allowing a resumption of the growth of the mycelium, in particular at the level of the edge 9 of the part 30 but also on all the rest of the external surface of the part 30 by forming a finishing “skin” presenting a satisfactory aesthetic appearance (as is the case on the part 30 represented in [Fig.6]) for any type of application. This fifth step E5 also makes it possible to mechanically consolidate the entire part, the rigidity and mechanical resistance of which continue to increase during this step.

[0046] In a sixth step E6, illustrated in [Fig.6], the part 30 obtained is subjected to the end of said fifth step E5 to drying outside said protective envelope. In the embodiment illustrated in the figures, at the end of the fifth step E5, the protective envelope 14 is removed and the part 30 is recovered (keeping its support 12 or not). As can be seen in [Fig.6], the edge 19 of the part 30 has a better surface appearance than in [Fig.5] (edge ​​9), of the same quality as the upper face 17 (face 7 in [Fig.5]). Drying can be carried out by leaving the part in the open air, at room temperature (at 22°C for example) for at least 6 hours, or by raising the temperature to 80°C in order to ensure that the growth of the mycelium is substantially stopped. This sixth step E6 has the particular purpose of reducing the humidity level of the room 30. This makes it possible to obtain a stable room 30, and to avoid any risk of subsequent development of mold in particular.The drying time during this sixth step E6 can be adjusted according to the size and morphology of the part 30, as well as the temperature, and can for example be between 6 hours and 72 hours, and more particularly between 12 hours and 36 hours. It is thus possible to manufacture various parts intended for various uses (as a container or even as wedges for the transport of fragile objects for example). A wide variety of shapes is of course possible, in particular other than the L-shape shown here as an example (in particular U-shape, with distinct thicknesses, oblique or curved shapes, etc.). The material forming the part 30 obtained at the end of this sixth step E6 is particularly light and has a density of between 70 kg / m3 and 160 kg / m3, for example of the order of 110 kg / m3.

[0047] A method according to the invention thus makes it possible to prepare parts of different shapes such as round, rectangular or oval boxes or even bases having reliefs and hollows of predetermined shapes.

Claims

Claims

1. Method for manufacturing a part (30) based on at least one lignocellulosic material and mycelium in which: • in a first step, an initial composition (2) is prepared comprising at least one lignocellulosic material in divided form, water and at least one mycelium precursor, • in a second step, said starting composition is placed on a predetermined support (10, 12) and said starting composition is covered with a protective envelope (14) for a period of between 24 hours and 96 hours, a pre-part (4) being obtained at the end of said second step, • in a third step, said protective envelope (14) is removed and said pre-part (4) is recovered, • in a fourth step, said pre-part (4) is cut so as to obtain said part (30), said pre-part having a humidity level greater than 40%, • in a fifth step,said part (30) obtained at the end of said fourth step is covered with a protective envelope (14) for a period of between 24 hours and 96 hours, • in a sixth step, said part (30) obtained at the end of said fifth step is subjected to drying outside of said protective envelope (14).,

2. Method according to claim 1, characterized in that said mycelium precursor is chosen from the group formed by basidiomycetes.

3. Method according to any one of claims 1 or 2, characterized in that said lignocellulosic material in divided form has at least one dimension less than 1.50 cm.

4. Method according to one of claims 1 to 3, characterized in that said lignocellulosic material in divided form is chosen from the group consisting of wood, grasses, herbaceous plants, straw, hemp, cotton, cereals, climbing plants, flowering plants, shrubs, bushes, fruit trees and mixtures thereof.

5. Method according to one of claims 1 to 4, characterized in that said second step and said fifth step are each carried out at a temperature between 18°C and 30°C.

6. Method according to one of claims 1 to 5, characterized in that said support comprises at least one mold.

7. Method according to one of claims 1 to 6, characterized in that said fourth step of cutting said pre-piece is carried out by at least one technique chosen from the group consisting of water jet cutting, laser cutting, cutting by a cutting tool and cutting by a vibrating tool.

8. Method according to one of claims 1 to 7, characterized in that said drying is carried out during said sixth step at a temperature between 5°C and 80°C.

9. Method according to one of claims 1 to 8, characterized in that said drying is carried out during said sixth step for a period of between 6 hours and 72 hours.

Images