Powdered thermoplastic composite material comprising a bio-sourced filler

Abstract

Powdered thermoplastic composite material comprising a bio-sourced filler One aspect of the invention relates to a powdered thermoplastic composite material, consisting of at least 90% by weight of a mixture of a thermoplastic matrix and a bio-sourced filler, the bio-sourced filler being composed of one or more powdered bio-sourced materials. The particle size of the thermoplastic composite material is for example such that 65.5% of the grains (by number) have a diameter strictly less than 32 µm and that 34.4% of the grains (by number) have a diameter of between 32 and 63 µm. According to another example, its particle size is such that D10 = 20 µm, D50 = 70 µm and D90 = 140 µm, preferably such that D10 = 10 µm, D50 = 30 µm and D90 = 70 µm.The bio-based filler mainly comprises powdered mycelium, powdered walnut shell, powdered olive kernel, powdered cellulose nanofiber, powdered starch, powdered alginate, powdered carbon black, or a mixture thereof. Figure to be published with the abstract: Figure 5.

Description

Title of the invention: Powdered thermoplastic composite material comprising a bio-sourced filler TECHNICAL FIELD OF THE INVENTION

[0001] The technical field of the invention is that of thermoplastic composite materials, and in particular that of thermoplastic composite materials composed of a thermoplastic polymer matrix, a filler and optionally other additives present in lower percentages. TECHNOLOGICAL BACKGROUND OF THE INVENTION

[0002] Nowadays, particularly for environmental, ecological and economic reasons, there is a growing and urgent need to replace as much as possible plastic materials obtained from fossil resources with bio-sourced materials, that is to say with materials derived from renewable organic materials, of plant or animal origin.

[0003] However, there is a need for a thermoplastic composite material that is both more environmentally friendly and ecologically sound, while being suitable for manufacturing an article by 3D printing and / or injection molding.

[0004] By thermoplastic composite material is meant here a material composed of a thermoplastic polymer matrix, a filler and optionally other additives, for example modifiers and plasticizers, present in lower percentages. The role of the filler is usually to reinforce the polymer matrix and / or to reduce its cost by partially replacing it with a less expensive material. Summary of the invention

[0005] The invention provides a solution to the problems mentioned above, by providing a powdered thermoplastic composite material combining a thermoplastic polymer and a bio-sourced filler, which can be used for both 3D printing and injection molding.

[0006] One aspect of the invention relates to a thermoplastic composite material consisting of at least 90% by weight of a mixture of a thermoplastic matrix and a bio-sourced filler, the bio-sourced filler being composed of one or more powdered bio-sourced materials and the thermoplastic composite material being in the form of a powder.

[0007] In the present application, the term bio-sourced material is understood to mean a material derived from biomass, and the term biomass means all renewable organic matter of plant, fungal or animal origin, such as, for example, organic plant waste, wood, branches and firewood, waste from industrial processing agri-food or wood, waste and rejects from livestock farming, residues from agricultural or forestry activities, waste from the agri-food industry specializing in the processing of livestock, etc.

[0008] A bio-sourced material is therefore a non-fossil material, that is to say it is not produced from oil, gas or coal.

[0009] Being in the form of a powder, the thermoplastic composite material of the invention can advantageously be used in additive manufacturing for 3D printing and for injection molding without having to significantly adapt these manufacturing processes according to the particular nature of the thermoplastic composite material.

[0010] It will be noted that substantially all the particle sizes of the bio-sourced filler can be used, the finest powders being used for example for injection molding while the finest powders, for example with a diameter of less than 100 μm, ideally with a diameter of less than 50 μm, are used in 3D printing. This advantageously makes it possible to use the entire bio-sourced filler powder and therefore to fully recover it in its entire particle size range.

[0011] It will be noted that for injection molding, the thermoplastic composite material powder of the invention is preferably transformed into granules, pellets or agglomerated particles before use.

[0012] The at least partial replacement of a polymer of petrochemical origin by a biosourced filler, i.e. derived from renewable, non-polluting and inexpensive organic materials, not only makes it possible to reduce the cost of the thermoplastic composite material, but also to reduce its environmental and ecological impact.

[0013] It will be noted that the thermoplastic composite material of the invention is advantageously capable of being recycled or reusable. For example, in printing by multi-jet fusion (MJF) technology or by selective laser sintering (SLS) technology, the powder which is neither sintered nor bonded can be reused in subsequent printing. Similarly, the article obtained from the thermoplastic composite material of the invention is also capable of being recycled.

[0014] According to another aspect of the invention, the bio-sourced filler mainly comprises powdered mycelium, powdered walnut shell, powdered olive kernel, powdered cellulose nanofiber, powdered starch, powdered alginate, powdered carbon black or a mixture thereof.

[0015] These bio-sourced materials are in fact advantageous in that they are inexpensive, usually biodegradable, and can be derived from a production chain environmentally friendly, particularly from recycling and waste recovery.

[0016] They can also be crushed or ground to be sized to an optimal particle size for 3D printing or injection molding.

[0017] They preferably exhibit high thermal stability, ideally not decomposing before 200°C, particularly to withstand the temperature ranges applied to the matrix material in SLS / MJF printing without degrading. This is essential to ensure that the material retains its integrity during the laser sintering or heating process.

[0018] When intended for use in SLS or MJF type 3D printing, these bio-sourced materials advantageously exhibit suitable optical properties, in particular the ability to efficiently absorb laser energy, which is crucial for the sintering process in SLS and for the activation of the bonding agents in MJF, allowing lighter colored prints.

[0019] These bio-based materials also exhibit desirable mechanical properties, such as strength, flexibility, and durability, depending on the intended use of the printed object. They advantageously exhibit a coefficient of thermal expansion that allows for controlled expansion and contraction during the printing process, thereby reducing the risk of deformation or deterioration.

[0020] In the case of MJF printing, the bio-sourced materials of the invention are advantageously compatible with the bonding agents used in the process, ensuring effective bonding and cohesion in the final product.

[0021] Finally, factors such as toxicity, dust generation and flammability are very low, or even harmful for these bio-sourced materials, which advantageously guarantees the safety of operators and the environment when these materials are handled.

[0022] Mycelium is of growing interest due to its low energy consumption during production, the absence of by-products and its numerous potential applications. In addition, it is biodegradable and can be grown locally. The use of mycelium supports sustainable practices, as it is a renewable resource that can be grown and harvested with minimal environmental impact.

[0023] Other benefits of mycelium stem from its inherent composition and structure. Mycelium contains, among other things, a significant proportion of chitin, which provides structural integrity and strength, polysaccharides, which contribute to flexibility and resilience, and proteins, lipids, and minerals such as calcium, which contribute to the material's overall functionality and durability.

[0024] Mycelium constituents, such as chitin and polysaccharides, can undergo crosslinking processes during the printing or molding process. This is particularly effective at specific temperatures and / or when using reactive bonding agents in multi-jet fusion (MJF) printing.

[0025] The biochemical components of the mycelium can react selectively with certain resins or modifiers, in particular used as binding agents, which makes it possible to customize the properties of the materials, adapting to the specific needs of the final application.

[0026] Due to its varied composition, mycelium can be designed to have specific mechanical, physical and structural properties, making it suitable for a wide range of applications. For example, its biocompatibility allows its use in the biomedical field.

[0027] Finally, the properties of mycelium make it well suited to injection molding techniques, but also to additive manufacturing techniques, offering a unique choice of materials for these types of applications.

[0028] In conclusion, the rich composition of mycelium, its crosslinking capabilities, its durability, its versatility in applications and its compatibility with advanced manufacturing techniques make it a very advantageous bio-based material, offering unique opportunities compared to other bio-based materials in various industrial and technological fields, including 3D printing and injection molding.

[0029] As a by-product of the food industry, walnut shells represent a sustainable and environmentally friendly material choice. Their use in manufacturing promotes waste reduction and supports a circular economy. Walnut shells are readily available from agricultural by-products, providing a consistent and scalable supply for industrial applications, including large-scale 3D printing or injection molding projects.

[0030] Walnut shells, when processed into a form suitable for composite materials, offer several distinct advantages over other bio-based materials. These advantages are particularly relevant in the context of advanced manufacturing technologies such as SLS and MJF technologies.

[0031] Indeed, when incorporated into composites for SLS / MJF printing, walnut shells can improve the mechanical strength and durability of the final products, making them suitable for a range of applications. They also exhibit good compatibility with different types of polymers used in SLS / MJF printing, allowing the creation of various composite materials with varied properties.

[0032] Walnut shells have superior thermal stability, making them ideal for high-temperature environments, especially in SLS / MJF printing. This property ensures that the material maintains its structural integrity during the printing process. It is also a durable material.

[0033] Walnut shells have natural abrasive qualities, making them suitable for applications where surface finish is important. This can be particularly beneficial in the post-processing stages of 3D printed parts.

[0034] In conclusion, the high thermal stability, abrasive properties, durability, scalability, mechanical improvement, polymer compatibility and material innovation potential position walnut shells as a highly advantageous bio-based material for various advanced manufacturing technologies, including 3D printing and injection molding.

[0035] Similarly, as another by-product of the olive oil industry, olive pits are readily available, ensuring a stable and scalable supply for large-scale production in advanced manufacturing technologies. Olive pits also represent a sustainable material choice. Their use supports environmentally friendly manufacturing practices, promotes waste reduction, and aligns with the principles of a circular economy, reducing waste and improving the overall sustainability of the manufacturing process. Olive pits have several advantages over other bio-based materials, and their unique properties are particularly beneficial in the context of industrial applications, including large-scale 3D printing or injection molding projects.

[0036] Olive kernel powder exhibits exceptional thermal stability, making it suitable for high-temperature processes such as those involved in SLS / MJF printing. This stability ensures that the material retains its integrity and does not degrade under laser sintering temperatures.

[0037] The high density of olive kernel powder contributes positively to the mechanical strength and weight of the final printed product, making it particularly suitable for applications where robustness is required.

[0038] Olive kernel powder exhibits inert behavior, especially during compounding and printing processes, ensuring compatibility with various polymers and maintaining the desired properties of the composite material.

[0039] Olive kernel powder can be combined with other materials to create composites with properties suitable for specific applications in printing. SLS / MJF, such as improved thermal resistance or customized mechanical characteristics.

[0040] For injection molding or additive manufacturing, the incorporation of olive kernel powder into molding and printing materials can lead to the development of composites that are not only performance-oriented, but also environmentally sustainable. This makes it an attractive option for industries seeking to balance functionality and ecological responsibility.

[0041] In summary, the high thermal stability, high density, inert behavior, durability, availability, and potential for improving the properties of olive kernel powder make this powder a highly advantageous bio-based material for various advanced manufacturing applications, including 3D printing and injection molding.

[0042] Cellulose nanofiber (CNF), also known as cellulose nanofibrils or nano-fibrillated cellulose, also offers a multitude of advantages over other bio-based materials, and its unique properties make it particularly suitable for applications in advanced manufacturing techniques, including SLS / MJF printing.

[0043] The exceptional strength and stiffness of NFC improves the mechanical properties of composite materials used in injection molding and 3D printing. This reinforcement can lead to molded or printed objects with superior durability and performance.

[0044] The lightweight characteristic of NFC is advantageous because it contributes to the production of lighter yet strong components, desirable in sectors such as aerospace and automotive.

[0045] The high surface area of ​​NFC facilitates better interaction and bonding with polymers commonly used in injection molding and 3D printing, resulting in improved material cohesion and superior structural integrity of printed objects.

[0046] The versatility of NFC functionalization allows the properties of these materials to be tailored to meet the specific requirements of the manufacturing techniques used, such as improved thermal resistance or modified surface properties.

[0047] The barrier properties of NFC are beneficial for creating molded or MJF-printed objects that require protection from gases or moisture, particularly in packaging and biomedical applications.

[0048] Due to its optical transparency, NFC can be an ideal component in molding and printing materials for applications that require both transparency and resistance, as in the field of optoelectronics. In addition, it is ideally suited for MJF printing, where white powders are preferred.

[0049] Similarly, due to its energy absorption and damping properties, NFC can significantly improve these properties in molded or printed objects, particularly in applications requiring vibration damping or energy absorption, such as protective equipment or automotive components.

[0050] Thus, NFC can be used to develop advanced composite materials that not only exhibit improved performance, but also contribute to more sustainable manufacturing practices. Its incorporation into molding or 3D printing materials can lead to the creation of objects with improved strength-to-weight ratio, functional versatility, and a reduced environmental footprint.

[0051] In summary, the unique combination of high strength, light weight, high surface area, functionalization adaptability, barrier properties, optical transparency and energy absorption capabilities, as well as its suitability for injection molding and 3D printing applications, position NFC as a highly advantageous bio-based material for a wide range of innovative uses.

[0052] Powdered starch and powdered alginate are also advantageous in that they are white and do not absorb light, which allows, for example, their use neat with plasticizers or small amounts of thermoplastic resin in the powder bed in MJF printing processes where exposure to light is by means of a projector (as opposed to the selective laser beam in SLS printing).

[0053] Carbon black, better known as soot, is also an advantageous bio-sourced filler. It can, for example, be obtained from many waste materials, such as coconut shells for example, in particular by calcination, which makes it possible to recover waste, in particular that from the food industry. Due to its black color, this type of bio-sourced filler cannot, however, be used in MJF printing, but is very suitable for SLS printing. It has excellent thermal stability and can be supplied with a very fine particle size, which makes it suitable for SLS printing.

[0054] According to another aspect of the invention, the grain size of the thermoplastic composite material is such that 50% or more of the grains (by number) have a diameter strictly less than 32 μm and such that 50% or less of the grains (by number) have a diameter of between 32 and 63 μm.

[0055] According to an additional aspect of the invention, the particle size of the thermoplastic composite material is such that D10 = 20 pm, D50 = 70 pm and D90 = 140 pm, preferably such that D10 = 10 pm, D50 = 30 pm and D90 = 70 pm.

[0056] These granulometries are advantageous in that, when used in additive manufacturing for 3D printing and for injection molding, it is not necessary to modify the equipment usually used for the implementation of these manufacturing processes.

[0057] These particle sizes allow in particular good homogeneity of the mixture. Indeed, when the size (and density) of the particles of the bio-sourced filler correspond(s) to that of the thermoplastic resin powder, the homogeneity and packing behavior of the powder bed are improved, which results in better printing quality. In the case of injection molding, where the molten material is mixed using a screw in order to obtain a certain homogeneity, a homogeneous distribution of the particle size in the bio-sourced filler is less essential.

[0058] These particle sizes, corresponding to grains sized according to an optimal particle range, advantageously improve the fluidity and spreading of the powder during additive manufacturing, which ensures that a uniform layer of material can be deposited during the printing process, which is crucial for obtaining high-resolution and uniform prints, with a constant layer thickness.

[0059] Particle size and distribution are particularly critical for SLS / MJF printing. Generally, a narrow particle size distribution in the range of 20 to 100 μm is preferred because this size range allows for efficient compaction and melting / sintering of the particles.

[0060] According to one aspect of the invention, the thermoplastic matrix is ​​composed of one or more thermoplastic polymers of petrochemical or biosourced origin. Indeed, the use of a thermoplastic polymer is particularly well suited to additive manufacturing and injection molding. The use of biosourced thermoplastic polymer is advantageous in that it makes it possible to reduce the overall environmental and ecological impact of the composite material in an additional manner.

[0061] According to another aspect of the invention, the thermoplastic polymer is chosen from at least one of the following polymers and their mixture: thermoplastic elastomers (TPE), thermoplastic polyurethanes (TPU), thermoplastic polyamides (PA), thermoplastic polyesters, thermoplastic starches (TPS), thermoplastic vinyl polymers, thermoplastic polyolefins, thermoplastic polyacrylates and thermoplastic polyacetals. Indeed, the use of such polymers is particularly well suited to additive manufacturing and / or injection molding.

[0062] Among the thermoplastic polyamides (PA), it is advantageous to use PA 11 and / or PA 6-10 which can be biosourced.

[0063] Among the thermoplastic polyesters, it is advantageous to use polyhydroxyalkanoates (PHA), polylactic acid (PLA), polybutylene succinate (PBS), polyethylene furanoate (PEF) which can be partially biosourced, as well as polycaprolactone (PCL), polybutylene adipate terephthalate (PBAT) which are biodegradable and can be partially biosourced.

[0064] It will be noted that the thermoplastic starch of the thermoplastic matrix and the powdered starch of the bio-based filler can be the same material. While in the thermoplastic matrix, the starch is plasticized and used as the bio-based filler, pure virgin starch can be used as the bio-based filler.

[0065] TPUs are preferred because they have a unique combination of properties that make them suitable for a wide range of applications, including 3D printing. TPUs are relatively easy to print, especially compared to other flexible materials. They flow smoothly through the printer nozzle and adhere well to the print bed.

[0066] TPUs also exhibit very high flexibility and elasticity, allowing the creation of parts that can stretch or compress and return to their original shape, ideal for flexible hinges, seals, and other parts requiring movement. Despite their flexibility, TPUs are also very durable, resisting abrasion, wear, and tear, making them suitable for creating parts that must withstand demanding conditions, such as protective housings and gears. Likewise, TPUs are resistant to many oils, greases, and various chemicals, making them ideal for industrial and mechanical applications where exposure to such substances is common. In addition, TPUs can withstand a wide range of temperatures without losing their properties, which is crucial both for the printing process and for the functional use of the printed objects.TPUs also exhibit excellent layer bonding, which helps create strong and reliable prints in 3D printing, where good layer adhesion is essential for structural integrity.

[0067] TPUs can be used in a wide variety of applications, from automotive parts to medical devices, with their versatility extending from industrial uses to consumer products. This is because TPUs can produce parts with a smooth surface finish, which is aesthetically pleasing and reduces the need for post-processing. Similarly, the properties of TPUs can be modified during the manufacturing process, allowing for different levels of hardness and flexibility. This customization means that TPUs can be tailored to specific application requirements. In addition, some TPUs can be biocompatible, making them safe for use in medical devices that come into contact with skin or other tissues.

[0068] Due to these advantages, TPUs represent a preferred choice for 3D printing, especially in applications where a combination of flexibility, durability and resistance to external factors is required. Its versatility makes it an essential material for prototyping and producing functional parts in various industries.

[0069] Polyamides (PA) or nylons (e.g. PA6, PA66) are preferred for their toughness and temperature resistance. PAU, for example, can be produced from castor oil and is a renewable alternative to fossil polyamides.

[0070] Polyesters derived from fossil resources, such as polyethylene terephthalate (PET), are preferred for their strength and durability. Some polyesters derived from fossil resources but partially biological, such as polycaprolactone (PCL) or polybutylene adipate terephthalate (PB AT) are preferred due to the diversity of their properties, their biodegradability, their good compatibility with bio-based fillers and their commercial availability.

[0071] Bio-sourceable polyesters, such as polylactic acid (PLA), polybutylene succinate (PBS) and polyethylene furanoate (PEF) are preferred for their high content of bio-sourced material, good biodegradability and mechanical strength.

[0072] Polyhydroxyalkanoates (PHAs) are preferred for the possibility of their biosynthesized production, for their excellent biodegradability and for their various mechanical properties.

[0073] Thermoplastic starch (TPS) is preferred for its abundant availability, biodegradability, and compatibility with other biopolymers.

[0074] According to one aspect of the invention, the thermoplastic composite material according to the invention comprises from 5 to 40% by weight, preferably from 10 to 20% by weight, of bio-sourced filler.

[0075] The higher the bio-sourced filler content in the mixture, the lower the carbon footprint of the thermoplastic composite material, but a high bio-sourced filler content has a negative impact on the adhesion of the layers in 3D printing because it may then be necessary to significantly adapt this manufacturing process depending on the particular nature of the thermoplastic composite material. A high bio-sourced filler content is also likely to have an impact on the mechanical properties of the material, in particular on its elastic properties. Indeed, the higher the bio-sourced filler content, the more rigid and harder the sintered material is.

[0076] According to another aspect of the invention, the thermoplastic composite material comprises from 30 to 95% by weight, preferably from 60 to 90% by weight, of thermoplastic matrix.

[0077] According to an additional aspect of the invention, in addition to a biosourced filler and a thermoplastic matrix, the thermoplastic composite material further comprises from 0 to 20% by weight, preferably from 0 to 10% and more preferably from 0 to 5% of at least one additive.

[0078] Indeed, articles manufactured with such formulations for the thermoplastic composite material have shown satisfactory mechanical properties from the point of view of durability, mechanical strength, damping properties and aesthetic appearance, which meet the desired and expected results while reducing the carbon footprint of the product. Of course, for flexible materials, properties such as tensile strength, elongation at break and abrasion resistance are generally reduced by the addition of a bio-based filler.

[0079] According to one aspect of the invention, at least one additive is selected from the list consisting of colorants, flame retardants, bonding agents, finishing agents, detailing agents, plasticizers, coupling agents, heat stabilizers, heat control agents, melting inhibitors, UV stabilizers, lubricants, nucleating agents, solvents, compatibilizers, prepolymers, chain extenders, crosslinking agents, catalysts, fluidizers, surface modifiers and additives intended to improve laser absorption. These additives are advantageously intended to adjust and improve the mechanical properties of the articles manufactured with the thermoplastic composite material of the invention and / or to improve the manufacturing processes therefrom.

[0080] According to one aspect of the invention, the thermoplastic composite material has the following formulation:

[0081] from 10 to 40% by weight, preferably from 15 to 25%, of bio-sourced filler,

[0082] from 50 to 95% by weight, preferably from 75% to 90%, of matrix thermoplastic, and

[0083] from 5 to 15% by weight, preferably from 8 to 12%, of at least one additive.

[0084] This formulation is advantageous in that it is particularly suitable for injection molding, in particular when among the additives, the thermoplastic composite material mainly comprises one or more plasticizers.

[0085] It will be noted that in this formulation, the biosourced filler can, for example, have any particle size, in particular greater than 100 μm.

[0086] According to another aspect of the invention, the thermoplastic composite material has the following formulation:

[0087] from 5 to 20% by weight, preferably from 10 to 15%, of bio-sourced filler,

[0088] from 75 to 95% by weight, preferably from 85 to 95%, of thermoplastic matrix, and

[0089] from 0 to 20% by weight, preferably from 0 to 10% by weight of at least one additive.

[0090] This formulation is advantageous in that it is particularly suitable for additive manufacturing, for example by SLS or MJF, in particular when in the thermoplastic matrix, the thermoplastic composite material comprises polyurethanes, polyamides or thermoplastic polyesters.

[0091] It will be noted that in this formulation, the biosourced filler is preferably in the form of a fine powder, with a particle size preferably less than 100 μm and more preferably less than 50 μm. Similarly, the thermoplastic matrix is ​​preferably in the form of a fine powder, with a particle size preferably of approximately 50 μm.

[0092] According to one aspect of the invention, in this second formulation the thermoplastic polymer is preferentially chosen from the following polymers and their mixture: polyamide 11 (PAU), polyamide 12 (PA12), polystyrene (PS), thermoplastic elastomers (TPE), polyetherimide (PEI), polyetherimide (PEI), polyethersulfones (PESU) and polymers from the polyaryletherketone family (PAEK).

[0093] According to one aspect of the invention, this second formulation comprises at least one additive chosen from the list consisting of additives formulated to improve laser absorption, bonding agents, crosslinking agents, finishing agents, detailing agents, plasticizers, thermal control agents, melting inhibitors, colorants, surface modifiers, stabilizers, solvents and compatibility improvers.

[0094] According to another aspect of the invention, in particular in MJF printing, one of the aforementioned additives is a colorant incorporated in glycerin. Indeed, this additive has shown great effectiveness in binding the powdered bio-sourced filler and the powdered thermoplastic matrix, whereas it is not generally used as a binding agent or detailing agent in 3D printing.

[0095] Another aspect of the invention relates to a method for manufacturing an article from a thermoplastic composite material, this article being manufactured by injection molding or by additive manufacturing from a thermoplastic composite material according to the invention. This method is advantageous in that it makes it possible to manufacture an article less expensively and with a lower environmental and ecological impact.

[0096] According to one aspect of the invention, the article is manufactured by additive manufacturing using 3D powder bed printing technology.

[0097] According to another aspect of the invention, the 3D printing technology is a multi-jet fusion (MJF) technology or a selective laser sintering (SLS) technology.

[0098] Indeed, these technologies are advantageously suited to the use of a powdered material.

[0099] The invention and its various applications will be better understood by reading the following description and examining the accompanying figures. BRIEF DESCRIPTION OF THE FIGURES

[0100] The figures are presented for information purposes only and in no way limit the invention.

[0101] [Fig.l] illustrates the results for four cyclic tensile tests carried out on tensile samples made from a thermoplastic composite material according to the invention comprising TPE and 40% mycelium.

[0102] [Fig.2] is a histogram illustrating the evolution of the maximum stress for the tests of [Fig.l].

[0103] [Fig.3] is a histogram illustrating the evolution of the deformation at the maximum stress for the tests of [Fig.l].

[0104] [Fig.4] is a photo of tensile test samples printed by SLS with 90% of Ultrasint® TPU 88A and 10% mycelium powder.

[0105] [Fig.5] is a photo of a part with complex geometry printed by SLS with 90% Ultrasint® TPU 88A and 10% mycelium powder.

[0106] [Fig.6] illustrates the particle size distribution of a first mycelium powder designated as Mycelium 1.

[0107] [Fig.7] illustrates the particle size distribution of a second powder of mycelium designated as Mycelium 2.

[0108] [Fig.8] illustrates the results of a thermal characterization test for a powder comprising 100% TPU alone.

[0109] [Fig.9] illustrates the results of a thermal characterization test for a powder comprising 90% Ultrasint® TPU 88A and 10% fine mycelium powder.

[0110] [Fig. 10] illustrates the results of a thermal characterization test for a powder comprising 90% Ultrasint® TPU 88A and 10% very fine mycelium powder.

[0111] [Fig. 11] illustrates the results of a thermal characterization test for a powder comprising 90% Ultrasint® TPU 88A and 10% olive kernel powder.

[0112] [Fig. 12] illustrates the dimensions of a test sample printed by SLS with powders according to the invention.

[0113] [Fig. 13] illustrates printing results of test samples printed by SLS at three different laser speeds with a powder comprising 90% Ultrasint® TPU 88A and 10% very fine mycelium powder.

[0114] [Fig. 14] illustrates printing results of test samples printed by SLS with three different powders according to the invention, with the printing parameters of method S2 given in [Table 9].

[0115] [Fig. 15] is a side view of the test sample located on the left in [Fig. 14].

[0116] [Fig. 16] illustrates results of printing samples of complex shapes by SLS with two different powders according to the invention.

[0117] [Fig. 17] illustrates the main tensile properties of SLS-printed test samples in the horizontal X / Y plane with the printing parameters of method S2 given in [Table 9], with three different powders according to the invention and two different TPU-only powders for comparison.

[0118] [Fig. 18] illustrates the main tensile properties of SLS-printed test samples in the Z direction with the printing parameters of method S2 given in [Table 9], with two different powders according to the invention and two different TPU-only powders for comparison.

[0119] [Fig. 19] illustrates the main tensile properties of test samples printed by SLS with two different laser speeds with a powder according to the invention. DETAILED DESCRIPTION

[0120] Unless otherwise indicated, the % given in this text are percentages by weight.

[0121] The thermoplastic composite material according to the invention consists of at least 90 % by weight of a mixture of a thermoplastic matrix and a bio-sourced filler.

[0122] This thermoplastic composite material is preferably intended to serve as a raw material for the manufacture of articles, and in particular sports articles such as a part of a shoe (upper or sole for example), a textile garment, a bicycle part, a table tennis table element, a luggage reinforcement part, etc.

[0123] For this purpose, the thermoplastic composite material is in the form of a powder, which allows it to be used in additive manufacturing or for injection molding. Indeed, such a composition has shown satisfactory results for the manufacture of articles by 3D printing and by injection molding.

[0124] According to one embodiment, the grain size of the thermoplastic composite material is such that at least 50% of the grains (by number) have a diameter strictly less than 32 μm and such that at most 50% of the grains (by number) have a diameter between 32 and 63 μm.

[0125] Preferably, the grain size of the thermoplastic composite material is such that 65.5% of the grains (by number) have a diameter strictly less than 32 μm and such that 34.4% of the grains (by number) have a diameter between 32 and 63 μm.

[0126] According to another embodiment, the particle size of the thermoplastic composite material is such that D10 = 20 pm, D50 = 70 pm and D90 = 140 pm, preferably such that D10 = 10 pm, D50 = 30 pm and D90 = 70 pm. For example, D10 = 20 pm means that 10% of the grains (by number) have a diameter less than 20 pm, while D50 = 70 pm means that 50% of the grains (by number) have a diameter less than 70 pm, and so on.

[0127] It will be noted that D10 is always smaller than D50 which is smaller than D90, and the closer their values ​​are, the more homogeneous the grain size.

[0128] The thermoplastic composite material of the invention comprises from 5 to 40% by weight, preferably from 10 to 20% by weight, of bio-sourced filler. This bio-sourced filler is suitable for use in injection molding or additive manufacturing, in particular by MJF or SLS technology.

[0129] According to one embodiment, the mixture of a thermoplastic matrix and a bio-sourced filler comprises between 10% and 20% by weight of bio-sourced filler, in particular when the thermoplastic matrix is ​​a thermoplastic elastomer (TPE) or a thermoplastic polyurethane (TPU). Indeed, such a composition has shown satisfactory results for the manufacture of articles by 3D printing and by injection molding, in particular when it is desired to favor the elastic character of the material.

[0130] According to another embodiment, this percentage by weight of biosourced filler may be between 10% and 40%, preferably between 15 and 25%, when the thermoplastic matrix is ​​a thermoplastic elastomer (TPE), a thermoplastic polyurethane (TPU) or a thermoplastic polyamide, in particular polyamide 11 (PA11) or polyamide 12 (PA12). Indeed, here too such a composition has shown satisfactory results for the manufacture of articles by 3D printing and by injection molding, in particular when it is desired to favor the rigid nature of the material.

[0131] In order to recover bio-sourced organic waste, the composite material according to the invention comprises a bio-sourced filler, which is therefore derived directly or indirectly from biomass. This bio-sourced filler can, for example, come from mushrooms, fruit shells, coffee grounds, etc. In general, it can come from any bio-sourced organic product which makes it possible to directly or indirectly recover waste or an inexpensive material derived from renewable organic materials, of plant, fungal or animal origin.

[0132] In addition to the bio-sourced filler, the composite material according to the invention may comprise a non-bio-sourced filler.

[0133] Generally speaking, for economic, ecological and environmental reasons, it is advantageous to have the largest possible quantity of bio-sourced filler in the composite material of the invention. However, too high a quantity of bio-sourced filler is likely to degrade the mechanical and aesthetic properties of the articles manufactured from such a composite material.

[0134] According to a preferred embodiment of the invention, the bio-sourced filler comprises predominantly powdered mycelium, powdered walnut shell, powdered olive kernel, powdered cellulose nanofiber, powdered starch, powdered alginate, powdered carbon black, or a mixture of one or more of these components. By "predominantly", it is meant that the powdered mycelium, powdered walnut shell, powdered olive kernel, powdered cellulose nanofiber, powdered starch, powdered alginate or a mixture of one or more of these components represents more than 50% by weight of the total bio-sourced filler.

[0135] Furthermore, the ground bio-based filler can be subjected to pretreatment processes to impregnate it with additives, chemically modify the particle surface or embed the sharp particles in a spherical thermoplastic matrix, thus facilitating the sintering process in the context of SLS / MJF technology.

[0136] The powdered mycelium used in the invention is preferably obtained from mushroom cultivation, which is a biotechnological process during which, by decomposing a feed substrate, a fungus creates an interconnected mycelium network. Advantageously, the substrate may be a waste, generally organic, and of low value, for example such as straw, plants or sawdust. It may also be plastic waste, cigarette filters or other waste that is usually difficult to recover. The mycelium filaments are called hyphae, consisting of elongated cells. The cell wall of the mycelium is made up of chitin, glucans, proteins and lipids, the concentration of which depends on the feed substrate which ultimately defines the properties of the mycelium.Thus, the mycelium is a tenacious mixture of chitin-glucan matrices and filamentous intracellular crosslinking which, once rendered inert (also called inactivated) and reduced to powder, can constitute a bio-sourced load usable in the context of the invention.

[0137] After their growth, the mycelial strains are preferably inactivated by disinfection, sterilization or cooking, more preferably by autoclaving in order to kill the fungus but without destroying the mycelium, which can then be reduced to powder, for example by grinding, to constitute all or part of the biosourced charge of the composite material according to the invention.

[0138] Among the mushrooms used, we can for example cite ganodermataceae, in particular Ganoderma lucidum, oyster mushrooms, in particular Pleurotus ostreatus, and polyporaceae, in particular Trametes versicolor.

[0139] The powdered walnut shell used in the invention is preferably obtained from walnut shells from the agricultural exploitation of edible nuts, produced by walnut trees, trees of the Juglandaceae family, for example of the genus Juglans regia. The walnut is an oleaginous and high-energy nut, but only the fruit is usually used. Using the shell, reduced to powder, for example by grinding, therefore makes it possible to recover this waste from the food industry.

[0140] Similarly, the powdered olive kernel used in the invention is preferably obtained from olive kernels from olive farming, in particular for the purpose of producing oil or pitted olives. Here again, the use of the kernels, reduced to powder, for example by grinding, therefore makes it possible to recover this waste from the agri-food industry.

[0141] Cellulose nanofiber powder is primarily derived from plant-based materials. The most common sources are wood pulp and cotton. Cellulose nanofibers are extracted from these plant materials by mechanical or chemical processes. They are advantageous due to their strength, lightness, and biodegradability.

[0142] Starch is a carbohydrate found in many plants, particularly in their roots, tubers, and seeds. Common sources of starch powder are corn, potatoes, wheat, rice, and cassava. Starch powder is extracted by crushing these plant parts and processing them to separate the starch.

[0143] Alginate is extracted from brown algae, such as species in the kelp family. These algae are found in the oceans, particularly in cold regions. Alginate is extracted from the algae by a process that involves the use of alkaline solutions.

[0144] According to a preferred embodiment of the invention, the composite material comprises from 30 to 95% by weight, preferably from 60 to 90% of a thermoplastic matrix.

[0145] Preferably, the thermoplastic matrix comprises a thermoplastic polymer of petrochemical origin, a bio-sourced thermoplastic polymer or a mixture thereof. This polymer or this mixture of polymers is suitable for use in injection molding or additive manufacturing.

[0146] According to one embodiment of the invention, a thermoplastic polymer of the thermoplastic matrix may be a thermoplastic elastomer (TPE), a thermoplastic polyurethane (TPU), a thermoplastic polyamide (PA), a thermoplastic polyester, a thermoplastic starch (TPS), a thermoplastic vinyl polymer, a thermoplastic polyolefin, a thermoplastic polyacrylate, a thermoplastic polyacetal or a mixture thereof.

[0147] In addition to the thermoplastic matrix and the bio-sourced filler, the thermoplastic composite material according to the invention may comprise one or more additives. These additives represent from 0 to 20%, preferably from 0 to 10% and more preferably from 0 to 5% of the total weight of the thermoplastic composite material.

[0148] An additive is a substance added in small quantities to the general composition of the thermoplastic composite material for technological reasons or to improve certain characteristics. Thus, an additive is neither a matrix nor a filler.

[0149] One of these additives may for example be chosen from colorants, flame retardants, bonding agents, detailing agents, plasticizers, coupling agents, thermal stabilizers, UV stabilizers, lubricants, nucleating agents, compatibilizers and additives intended to improve laser absorption.

[0150] According to a preferred embodiment of the invention, a binding agent comprises a black dye and glycerin. Indeed, in this mixture acting as a plasticizer, glycerin is an excellent solvent for the black dye and this mixture has shown good results.

[0151] According to a first variant of the invention, the thermoplastic composite material has a formulation specifically adapted to injection molding.

[0152] For injection molding, the requirements differ from those for additive manufacturing and are lower. Indeed, a very large number of combinations of thermoplastic matrix and bio-based filler are possible. The requirements mainly arise from the desired properties of the final material, such as Shore hardness, tensile strength, etc.

[0153] For injection molding, the composite material comprises from 50 to 95% by weight, preferably from 75 to 90%, of thermoplastic matrix.

[0154] According to a second variant of the invention, the thermoplastic composite material has a formulation specifically adapted to additive manufacturing, and in particular to additive manufacturing by 3D printing. By "3D printing" is meant the direct deposition of a material from a printing device onto a substrate or a layer of material already printed. In one or more aspects of the invention, 3D printing comprises the extrusion of a material from a printing device onto a substrate or a layer of material previously printed. In other aspects of the invention, 3D printing comprises the ejection or jet (for example, by spraying) of droplets of a material from a printing device.In still further aspects of the invention, 3D printing comprises depositing a powder or granular material and consolidating said material by thermal activation using a selective laser beam or projector light source, which may be combined with depositing a bonding agent to enhance sintering of the powder or granular material. 3D printing according to the invention excludes injection. of a material into a cavity of a mold temporarily disposed adjacent a surface of the substrate, in which a shape, location, or thickness of the material injected onto the substrate is constrained by the mold according to conventional injection molding techniques.

[0155] Among the additive manufacturing processes capable of using the thermoplastic composite material of the invention, mention may in particular be made of powder bed additive manufacturing, for example based on the multi-jet fusion technology known under the English name Multi Jet Fusion and under the acronym MJF, or on the selective laser sintering technology known under the acronym SLS, from the English Selective Laser Sintering, the binding agent jet printing technology known under the English name Binder Jet Printing and under the acronym BJ3DP and the spraying technology known under the English name Spray.

[0156] SLS technology relies on laser energy to sinter the powder, while MJF technology uses a combination of bonding agents and a light projector. SLS materials often offer more limited color variation, resulting in parts that are generally white or gray unless dyed after printing. MJF parts have a more uniform black color due to the use of dark-colored bonding agents and can achieve smoother and more detailed surface finishes. BJ3DP technology is very similar to MJF, except that the detailing agent is absent.

[0157] Although all three techniques use thermoplastic base materials, the presence of the combination of two jets of materials, namely bonding agents and detailing agents, with light that induces sintering, MJF technology is advantageously a very versatile method for modifying the final properties of the material, such as its flexibility, strength and texture.

[0158] For additive manufacturing, the thermoplastic matrix preferably represents from 75 to 95% by weight, more preferably from 85 to 95%, of thermoplastic matrix of the thermoplastic composite material according to the invention.

[0159] The bio-sourced filler preferably represents from 5 to 20% by weight, more preferably from 10 to 15%, of the thermoplastic composite material according to the invention.

[0160] The additives preferably represent from 0 to 20% by weight, more preferably from 0 to 10%, of the thermoplastic composite material according to the invention.

[0161] Selective laser sintering SLS is a 3D printing process based on selective laser sintering without a liquid phase, where layers of powders are sintered or fused layer by layer using laser energy.

[0162] SLS printing mainly uses fine thermoplastic powders. Thus, the particle size of the thermoplastic composite material for SLS printing preferably varies from 20 to 100 micrometers, the uniform particle size ensuring uniform sintering and high-quality printing resolution.

[0163] For SLS printing, the material constituting the thermoplastic matrix according to the invention must have a specific melting point adapted to the laser sintering process, it must be able to melt without degrading under the heat of the laser. Preferred materials for the thermoplastic matrix according to the invention include polyamides (PA), for example such as polyamide 11 (PA11), polyamide 12 (PA12), polystyrene (PS), thermoplastic elastomers (TPE), thermoplastic polyurethanes (TPU), and high-performance polymers such as polyetherimide (PEI), polyethersulfones (PESU) or polymers of the polyaryletherketone family (PAEK), for example such as polyetheretherketone (PEEK) or polyetherketoneketone (PEKK), or a mixture thereof.

[0164] Among these polymers, those with a melting point above 300°C are more preferably preferred.

[0165] For SLS printing, among the additives of the thermoplastic composite material according to the invention, there may in particular be included at least one additive formulated to improve laser absorption, in an amount of 0 to 10% by weight in the thermoplastic composite material.

[0166] For SLS printing, the preferred bio-sourced fillers are powdered starch, powdered NFC, powdered mycelium and powdered olive kernels, in an amount representing from 10 to 20% by weight, preferably from 5 to 15%, of bio-sourced filler by weight in the thermoplastic composite material.

[0167] The table below gives examples of complete compositions of the composite material according to the invention intended for SLS printing.

[0168] [Tables 1] Compound Composition 1 Composition 2 Composition 3 Composition 4 Thermoplastic matrix Ultrasint® TPU 88A 90% Ultrasint® TPU 88A 90% Ultrasint® TPU 88A 90% Ultrasint® PA 1 190% Bio-based filler Mycelium powder 10% Olive kernel powder 10% NFC powder 1 0% Mycelium powder 10% Additives 0% 0% 0% 0%

[0169] MJF technology is a 3D printing process based on the fusion of powder layers where each layer is melted by infrared light at the appropriate locations thanks to the print head which deposits a heat-conducting and light-absorbing liquid (bonding agent), while an insulating liquid (detailing agent) is also applied to delineate the contours of the object to ensure high precision.

[0170] MJF printing also uses thermoplastic powders, the particle diameter preferably being between 60 and 100 pm.

[0171] For MJF printing, among the additives of the thermoplastic composite material according to the invention, there may in particular be included at least one binding agent, also referred to as a melting or binding agent, in an amount of 0 to 5% by weight relative to the thermoplastic composite material. This amount of 0 to 5% by weight relates to the binding agent alone; it is a content of non-volatile substances which does not take into account the weight of the solvent in which the binding agent may be present. Taking into account the solvent, which evaporates during MJF printing, the amounts of binding agent solubilized in a solvent could, for example, be of the order of 50 to 100% by weight.

[0172] When the bonding agent is sprayed onto the powder bed, it helps define the shape of each layer and enables the fusion process by absorbing light and melting the individual particles. The bonding agent is usually a black-colored liquid, which facilitates the absorption of heat from infrared light at the voxel to be printed.

[0173] However, in the context of using bio-based fillers, certain additives or components may be considered "binding agents" due to their role in facilitating the sintering process. Valuable and expensive components should be used in the binding agent rather than dispersed in the powder bed to enable economical production, even though the MJF process is considered to have high recyclability of excess powders.

[0174] A colorant is generally added to the binding agent to provide visual contrast during the printing process, thereby facilitating quality control and inspection.

[0175] In more complex and innovative systems, the additives may also include the products listed below.

[0176] Prepolymers: These are often the main component of thermoplastic matrix powders. Prepolymers can have different molecular weights and chemical compositions tailored to achieve the desired melting and sintering properties.

[0177] Chain extenders and crosslinkers: These low molecular weight compounds react with the prepolymers or with the surface of the thermoplastic matrix to form covalent bonds between the particles and the bio-based filler. They can also influence the melting point and flow properties of the thermoplastic matrix powder during the sintering process.

[0178] Catalysts: Catalysts are used to accelerate the reaction between prepolymers, chain extenders and the powdered thermoplastic matrix. Their presence can influence the sintering speed and the final properties of the material.

[0179] Stabilizers: Stabilizers such as antioxidants and light stabilizers are often added to thermoplastic matrix powders to improve their stability under laser sintering conditions and during application.

[0180] Fluidifiers and plasticizers: To improve the flowability of the thermoplastic matrix powder, fluidizers can be added. These allow a uniform layer of powder to be obtained during the printing process.

[0181] Dyes or pigments: For aesthetic purposes or to differentiate materials, dyes or pigments may be added to the thermoplastic matrix powders.

[0182] Compatibility agents: These are added to improve the compatibility between the different polymer components and the bio-sourced filler, thus ensuring a uniform sintering process.

[0183] In the case of MJF printing, a finishing agent can also be applied to the perimeter of the printed part before exposure to the projector light in order to prevent any further reaction in the powder bed and to ensure a high surface quality of the printed part. Solvents with a low or medium boiling point are therefore most often used. The use of glycerin can also be useful depending on the composition of the powder.

[0184] A detailing agent can be used to define the fine details and smooth surfaces of the printed object. It is generally applied to the outer perimeter and edges of the printed parts to modify the way heat is absorbed during the fusing process. The detailing agent helps to achieve high resolution and accuracy in the final print by controlling the spread of the fusing agent, the absorbed heat, and the subsequent melting and sintering of the powder. This is essentially to improve the fine features and accuracy of the printed parts.

[0185] The detailing agent is a liquid thermal control agent. It is designed to modify the heat absorption characteristics of the powder bed. By controlling how light is absorbed and partially limiting how heat is distributed, this agent can improve the accuracy of the sintering process, allowing for better resolution of surface details, usually by combining them with solvents.

[0186] The detailing agent generally consists of low boiling point solvents that absorb the heat of the process by evaporation and act as fusion inhibitors, preventing the powder from fusing in areas where the part should not form, resulting in better definition and sharper edges.

[0187] Other preferred additives include surface modifiers, thermal and UV stabilizers, solvents and compatibility improvers.

[0188] A surface modifier allows the characteristics of the surface of the print, such as gloss or texture, to be modified in order to obtain the desired aesthetic or functional properties.

[0189] A heat stabilizer helps ensure that the detailing agent remains effective throughout the printing process, particularly at high temperatures and other harsh conditions.

[0190] A solvent is often combined with a detailing agent, allowing them to remain in a liquid state for precise application. They evaporate during the printing process.

[0191] A compatibility enhancer ensures that the detailing agent works harmoniously with the thermoplastic composite material powder and the bonding agent, without causing unwanted reactions.

[0192] A plasticizer may be present in an amount representing 10 to 20% by weight of the thermoplastic composite material since certain composite materials may already comprise such an additive.

[0193] The thermoplastic composite material may comprise from 0 to 20% of plasticizer and from 0 to 10% of other types of additives. Indeed, certain thermoplastic materials used for the thermoplastic matrix may already comprise such additives.

[0194] The other additives may, for example, be present in an amount representing 0 to 10% by weight of the thermoplastic composite material.

[0195] Formulations for MJF printing can be provided to optimize the interaction between a detailing agent, a bonding agent, and a thermoplastic composite material powder to ensure that the final printed parts exhibit the desired mechanical properties, accuracy, and surface finish.

[0196] The combination of a detailing agent and a bonding agent in MJF printing allows the creation of parts with complex geometries and excellent mechanical properties.

[0197] It will be noted that for MJF printing, the thermoplastic composite material according to the invention used must be compatible with the bonding agent.

[0198] The thermoplastic composite powder material according to the invention must also have a specific color, generally white, to avoid absorption of the heat produced by the fusion lamp. If the color of the thermoplastic composite powder material is too dark, a detailing agent containing white pigments can be used to prevent the fusion of particles outside the printed perimeters.

[0199] For MJF printing, the thermoplastic composite material according to the invention must also have thermal properties allowing rapid melting within a narrow temperature window and rapid solidification. The chemical stability of the composite mixture and the added detailing and bonding agents within the processing temperature range is essential for a reliable and reproducible MJF printing process.

[0200] Thus, for MJF printing, the preferred materials for the thermoplastic matrix according to the invention include in particular polyamides (PA), for example such as polyamide 11 (PAU) or polyamide 12 (PA12), thermoplastic polyurethanes (TPU), other modified thermoplastics or a mixture thereof.

[0201] For MJF printing, preferred bio-based fillers are powdered starch, powdered NFC, powdered mycelium, and powdered olive kernels, in an amount representing, for example, approximately 10% by weight of the mixture of a thermoplastic matrix and a bio-based filler.

[0202] The table below gives examples of complete compositions of the composite material according to the invention intended for MJF printing.

[0203] [Tables2] Compound Composition 1 Composition 2 Composition 3 Composition 4 Thermoplastic matrix Ultrasint® TPU 88A 90% Ultrasint® TPU 88A 90% Ultrasint® TPU 88A 90% Ultrasint® PA 1 1 90% Bio-based filler Mycelium powder 10% Olive kernel powder 10% NFC powder 1 0% Mycelium powder 10% Additives 0% 0% 0% 0%

[0204] It can be seen that these compositions are the same as for SLS printing.

[0205] It will be noted that it is also possible to manufacture an article by MJF printing by binding a powder comprising only starch, alginate, mycelium or a mixture of these products, and a possible additive. In this particular case of the invention, the bio-sourced filler behaves both as a filler, but also as a thermoplastic matrix.

[0206] The table below gives an example of the composition of the composite material according to the invention intended for MJF printing in which the powdered mycelium serves both as a bio-sourced filler and as a thermoplastic matrix.

[0207] [Tables3] Composition 5 Mycelium powder 70-90% Plasticizer 5-15% Bonding agent 5-15%

[0208] These compositions have given excellent results when the binding agent is epichlorohydrin, glutaraldehyde, glyoxal or aqueous citric acid with a black pigment.

[0209] The spraying technology is based on the controlled spraying of a main material in liquid form onto the surface of a wall or substrate, which makes it possible in particular to obtain an article with a uniform thickness or different thicknesses depending on the region. For spraying, emulsions, suspensions or solutions of the main material are generally used. Thus, the main material comprises the composite material according to the invention and a liquid, such as water or a solvent. After spraying the main material, with or without additional steps, it is preferable to allow the produced article to dry before removing it from the surface. The drying process may include hardening or setting processes, depending on the choice of product. It is also known to add a reinforcing material, such as loose fibers between two layers of the sprayed material.Spray technology is particularly advantageous in that it allows the manufacture of flexible and / or stretchable articles, including inflatable articles.

[0210] The invention also relates to a method of manufacturing an article from a thermoplastic composite material as described above.

[0211] According to a first variant of the invention, this manufacturing method comprises a step of injection molding from a thermoplastic composite material having a formulation specifically adapted to injection molding.

[0212] According to a second variant of the invention, this manufacturing method comprises an additive manufacturing step from a thermoplastic composite material having a formulation specifically adapted to additive manufacturing. This additive manufacturing step is for example carried out by implementing a 3D printing technology, preferably a 3D printing technology on a powder bed, more preferably carried out by SLS or MJF.

[0213] For SLS / MJF printing, the two powders are mixed before filling the powder bed. The particle size distribution and density of the bio-based filler are crucial to achieve a homogeneous powder bed and a good printing result.

[0214] Tests

[0215] Tests were carried out with different formulations of thermoplastic composite material according to the invention. These tests are intended in particular to prove that these formulations make it possible to manufacture articles with satisfactory mechanical and aesthetic properties. While the injection molding technology does not represent any particular technical complexity, the tests also aim to prove that the different formulations of thermoplastic composite material according to the invention are also suitable for use in additive manufacturing by a 3D powder bed printing technology, for example by SLS or MJF, which is known to have specific and more rigorous criteria for the materials used compared to injection molding.

[0216] Tensile strength tests _(PAM technology)

[0217] A first series of tests to validate the tensile strength properties was carried out according to DIN 53504 with tensile samples (sometimes referred to as test pieces) manufactured according to the formulations and processes given in the following table. It should be noted that the samples were printed using pellet additive manufacturing technology, known by the acronym PAM, which is a technique halfway between 3D printing and injection molding and which therefore allows the feasibility of these two technologies to be validated quickly and at low cost. Indeed, PAM technology uses a nozzle as in 3D printing, and a screw where the main material is melted as in injection molding. Direct pellet extrusion technology, known by the acronym FGF, could also have been used.

[0218] [Tables4] Sample family Formulation Manufacturing process A 60% TPE + 40% Mycelium PAM B 100% TPU alone MJF C 100% TPU alone SLS D 90% TPU Ultrasint 88A + 10% Mycelium mMYCl SLS E 90% TPU Ultrasint 88A + 10% Mycelium mMYC2 SLS F 90% TPU Ultrasint 88A + 10% Olive kernel OK SLS

[0219] In sample A, the TPE is a proprietary matrix of the company KUORI, while the mycelium comes from two external deposits.

[0220] In samples D and E, MYC1 indicates a first mycelium powder called “fine”, the particle size distribution of which is given in [Fig.6], while MYC2 indicates a second mycelium powder called “very fine”, the particle size distribution of which is given in [Fig.7].

[0221] The table below gives the particle size of the bio-sourced fillers used in combination with Ultrasint 88A TPU for SLS printing.

[0222] [Tables5] Bio-sourced load Average particle size D 50 [pm] Maximum particle size [pm] MYC1 70 560 MYC2 32 63 OK 80 125

[0223] Ultrasint® TPU 88A is a conventional TPU powder intended for SLS printing and marketed by BASF, Switzerland. The properties of this material, as listed in the technical data sheet, are summarized in the table below.

[0224] [Tableauxô] Ultrasint® TPU 88A Appearance Natural white powder Density (bulk density) [g / cm3] 0.5 Density (printed part) [g / cm3] 1.1 Average particle size d50 [um] 70-90 Glass transition temperature [°C] -48 Melting temperature [°C] 120-150 Shore A hardness 88-90 Tensile modulus [MPa] X / Y direction 75 / 75 Ultimate tensile strength [MPa] X / Y direction 8 / 7 Elongation at break [%] X / Y direction 270 / 130

[0225] The tensile samples are all in the form of standardized flat test pieces (cf. [Fig.4] and [Fig. 12]). For the tests, three to four samples from each family were tested.

[0226] The SLS printed tensile samples were printed in a horizontal X / Y orientation.

[0227] All tensile samples are Type 1, with +10 mm on each side to improve grip and prevent slippage. The samples were printed so that the narrow section has the longest layers to ensure the best mechanical strength.

[0228] Cyclic tensile tests with increasing nominal strain were carried out, i.e. using a 25% increase in strain until failure. A long-stroke extensometer was used to measure the strain. The test speed was 10 mm / min. A preload of 2 Newton was induced.

[0229] The results of these tests are illustrated in [Fig.l] for tensile sample A.

[0230] Maximum stress deformation tests

[0231] A second series of tests to validate the maximum stress and the deformation at maximum stress was carried out on standardized tensile samples A, B and C.

[0232] The results of these tests are given in the table below. They are illustrated in the form of histograms in [Fig.2] and [Fig.3] for tensile sample A. In these histograms, the column represents the average of the four samples and the error bars are related to the standard deviation of the batch.

[0233] [Tables?] Sample Tensile strength X / Y (MPa) Tensile strength Z (MPa) Elongation at break X / Y (%) Elongation at break Z (%) A 2 + 10% - 11 + 7% - B 11 + 22% 7 ± 18% 104 + 43% 55 + 40% C 8 + 5% 4±5% 74 + 9% 16 + 15% D 7 + 26% - 85 + 37% - E 7 + 10% 2 ±31% 71 + 8% 7 + 20% F 7 + 4% 1 + 27% 59 + 12% 10 + 27%

[0234] From these results, it can be deduced that SLS-printed composites exhibit competitive material properties compared to pure reference materials with respect to tensile strength and elongation at break, while replacing 10% of fossil-based TPU with bio-based fillers.

[0235] The advantage of MJF printing over SLS printing is also highlighted, reflected by better layer adhesion and generally superior properties in the Z direction for MJF.

[0236] Particularly for thermoplastic composite materials, material disadvantages related to layer orientation can be eliminated thanks to the advanced fusion properties of MJF printing.

[0237] For the same composition, injection molding gives a superior result compared to additive manufacturing since the processing method mixes all the components homogeneously during introduction into the hot injection system by a screw mechanism. The sample obtained by injection molding has isotropic properties, while additive manufacturing has anisotropic properties depending on the printing orientation.

[0238] It should also be noted that no significant difference between samples of the same family was identified; it can be deduced that the behavior is reproducible given the technology used to print the samples.

[0239] As can be seen in the photos (see [Fig.4] and [Fig.5]), the surface quality of the print is excellent and comparable to that of a commercial SLS print. Tests have determined that the article obtained by SLS printing carried out with 10% mycelium and 90% TPU and illustrated in [Fig.5] has substantially the same mechanical properties as the same article obtained by SLS printing carried out with 100% TPU.

[0240] Other tests described below were carried out with SLS technology by the company KUORI.

[0241] One of the objectives of these tests is to find suitable printing parameters for the different powders and to understand how olive pits compare to mycelium in terms of mechanical properties after SLS printing.

[0242] The results should make it possible to define the broad outlines of a possible transfer or reproduction with MJF technology and to further explore the possibilities of transfer and reproduction with MJF technology.

[0243] Thermal characterization tests

[0244] Powders from samples in families C, D, E and F were characterized by Differential Scanning Calorimetry (DSC) on a TA Instruments DSC 25 to better understand the required printing parameters and the appropriate processing window.

[0245] The following thermal profile was used for the measurements:

[0246] - Step 1: Incremental heating at 10°C / min from 0°C to 200°C in a nitrogen atmosphere. This step aims to eliminate the thermal history of the sample.

[0247] - Step 2: Gradual cooling at 10°C / min from 200°C to 0°C in a nitrogen atmosphere.

[0248] - Step 3: Incremental heating at 10°C / min from 0°C to 200°C in a nitrogen atmosphere.

[0249] The results of these tests are given in [Fig.8] to [Fig. 11], respectively for families C, D, E and F, where the first heating cycle is represented in thin line and where the cooling cycle is represented in thick line.

[0250] These DSC thermograms reveal that the addition of 10% by weight of bio-based filler does not influence the melting or crystallization range of the powder. The four powders analyzed each have a melting range of approximately 130 to 150°C, with a peak at 142°C. The enthalpies of fusion are also not modified. The enthalpies of fusion also remain practically unchanged. As for the peak crystallization temperature, it remains constant at 108°C. These experimental data are in line with the specifications stated in BASF's datasheet, suggesting that identical printing parameters regarding temperature can be applied for SLS printing. Furthermore, the powders showed no signs of thermal degradation up to 200°C, indicating the feasibility of a recycling process.

[0251] Production of samples by SLS printing

[0252] The samples were printed using a SLS SI printer from Sintratec, Switzerland (laser = 2.3W, X = 445 nm), with a maximum volume of the printed object of 3.04 dm3 (130 mm x 130 mm x 180 mm). All samples were treated by sandblasting (Micropeen 950 ZPD, lepco Switzerland) to remove unsintered powder.

[0253] Powders from samples in families C, D, E and F were used to fill the SLS printer chambers and produce test samples. Five test samples with a thickness of 3.8 mm were printed during each printing session. Their dimensions are shown in [Fig. 12].

[0254] The appearance of these powders is given in the table below:

[0255] [Tables8] Sample family Formulation Color Visual inspection C 100% TPU alone White homogeneous D 90% TPU Ultrasint 88A + 10% Mycelium MYC1 Gray mycelium particles are clearly distinguishable E 90% TPU Ultrasint 88A + 10% Mycelium MYC2 Gray homogeneous F 90% TPU Ultrasint 88A + 10% Olive pit OK Off-white / brownish homogeneous

[0256] In preliminary experiments, pure Ultrasint 88A TPU powder was used for printing. However, no interaction was observed between the laser beam and the powder, hence no sintering occurred. On the contrary, with increasing temperature, a molten block was formed. This phenomenon is probably attributable to the white coloration of the powder, which leads to insufficient absorption at the laser wavelength, combined with the relatively low power of the Sintratec SI laser (2.3 W).

[0257] On the other hand, the addition of gray / brown bio-based fillers allowed for successful printing. Different printing parameters were tested. They are presented in the table below:

[0258] [Tables9] Method Heating temperature [°C] Printing temperature [°C] Laser speed [mm / s] Powdered surface Chamber Powdered surface Chamber SI 100.6 60.3 125.7 60.7 650.0 S2 100.6 60.3 120.7 60.7 450.0 S3 100.6 60.3 120.7 60.7 250.0

[0259] Effect of printing temperature: At a printing temperature of 125.7 °C (method SI), the produced test samples were enclosed in a compact block of powder, making powder recycling difficult. Even when lowering the printing temperature to 120.7 °C (methods S2 and S3), which is the lower threshold of the melting range, the unused powder failed to flow freely. Therefore, all experiments were conducted using 100% fresh, non-recycled powder.

[0260] Effect of laser speed: [Fig. 13] illustrates the results of SLS_MYC2 printed at three different laser speeds: Left: 650 mm / s. Middle: 450 mm / s. Right: 250 mm / s. Based on visual inspection, it appears that the sintering process has been improved for the lower speeds. Individual particles are indeed less visible. Considering the relatively good quality achieved at 450 mm / s and the reasonable printing time compared to the laser speed of 650 mm / s, it was decided to produce the samples for mechanical testing with the S2 method.

[0261] Effect of powder composition: The three powder qualities of samples from families D, E and F were used to produce test samples with the S2 method for mechanical testing. The resulting test samples are shown in [Fig. 14] and [Fig. 15]. From left to right in [Fig. 14]: SLS_MYC2 (family E), SLS_MYC1 (family D), SLS-OK (family F). [Fig. 15] is a side view of an SLS_MYC2 test sample, printed with the S2 method. Visually, the SLS_MYC1 powder appears grayer and less homogeneous than the SLS_MYC2 and SLS_OK powders, probably due to the broader particle size distribution of the MYC1 powder.

[0262] Printing complex hollow shapes

[0263] Compared to the more traditional fused deposition modeling (FDM) 3D printing technique, SLS printing makes it easy to fabricate hollow surfaces for which a support structure is usually required. The unmelted powder serves as a temporary support and can be recycled in a new print later. Therefore, more complex shapes were printed in a second step (see [Fig. 16]), using SLS_MYC2 (family E) and SLS_OK (family F) powders due to their superior performance. Initial tests with the S2 method proved difficult due to the presence of compact powder trapped inside the geometry and therefore difficult to remove without damaging the sample. To overcome this problem, the printing temperature was reduced by 5°C and the laser speed was reduced by 100 mm / s. The geometry was also scaled.The geometry was increased by a factor of 1.4 to enlarge the holes in the geometry and allow easier removal of the powder enclosed in the ball. The printing parameters used for SLS printing of complex hollow shapes are summarized in the table below.

[0264] [Tables 10] Method Heating temperature [°C] Printing temperature [°C] Laser speed [mm / s] Powdered surface Chamber Powdered surface Chamber S4 100.6 60.3 115.7 60.7 350.0

[0265] Mechanical properties

[0266] The mechanical properties of the test samples were tested by tensile measurements over three repetitions. The maximum strength (omax), breaking strength (ob), elongation at break (eb), as well as an approximation of Young's modulus (E) were extracted from the stress-strain curves.

[0267] As shown in the table below and [Fig. 17], the tensile properties are in a similar range for all formulations. Due to the high variability of the results, no conclusions can be drawn regarding the best performing powder in terms of mechanical properties. Compared to Ultrasint TPU 88A from BASF, the samples produced exhibit lower elongation at break, but similar tensile strength and higher modulus. Similar results were observed for KUORI materials when bio-based fillers were added inside a TPE matrix. Data provided by the applicant were used as references: an SLS reference and an MJF reference. The samples produced in this study performed as well as the SLS reference. Only in the Z direction can defects in layer adhesion be observed for the thermoplastic composite material samples. The MJF-printed reference, on the other hand, outperformed all other samples in terms of elongation at break and tensile strength. However, a direct comparison is not possible because MJF is based on a different sintering method.Nevertheless, the improvement in Z- properties resulting from the MJF process promises to compensate for the limitations encountered when using higher ratios of bio-based fillers.

[0268] [T ables 11] Omax (X / Y) [MP a] St. Dev. [MPa] 0b (X / Y) [MPa] St. Dev. [MPa] E (X / Y) [MPa] St. Dev. [MPa] eb (X / Y) [%] St. Dev. [%] SLS_MY Cl 6.69 1.69 ±25.3% 6.32 1.37 +21.7% 104.8 40.8 +38.9% 84.9 31.5 +37.1% SLS_MY C2 6.61 0.68+10.3% 6.61 0.68 +10.3% 131.5 28.1 +21.4% 71.3 5.9 +8.3% SLS_OK 7.01 0.29 +4.1% 6.88 0.48 +7.0% 135.5 37.8 +27.9% 76.2 9.3 +12.2% TPUFo umisseur 2 SLS 8 0.4 + 5% - - - - 74 7+9% TPUFo umisseur 1 MJF 11 2 + 22% - - - - 104 45 +43%

[0269] In [Fig. 17] are represented the main tensile properties of the three SLS powders printed with the S2 method in the horizontal X / Y plane. The Young's modulus (or elastic modulus) is represented by light hatching while the tensile strength is represented by dense hatching. The tests were carried out in triplicate. Two reference powders are given as examples. The tensile strength tensile strength and modulus of elasticity correspond to the left axis, elongation at break corresponds to the right axis.

[0270] The high standard deviation of the analytical results may be related to the method used to prepare the powders, namely hand mixing, which could lead to an inhomogeneous mixture. Other mixing methods could be investigated to obtain optimal results. However, it can be noted that the variability of the results is more pronounced for SLS_MYC1 which is the powder with the largest particle size and the broadest distribution. For further use of MYC1 as a bio-based filler, sieving and / or grinding is advisable.

[0271] Effect of printing direction: The effect of printing direction on mechanical properties was evaluated by printing the test samples in the Y / Z plane. The mechanical properties were significantly reduced compared to samples printed in the horizontal X / Y plane, both for the samples printed by KUORI and for the reference samples. The analysis in the Y / Z plane provides important insight into the layer adhesion of the printing process. SLS printing generally results in less efficient sintering of particles from one layer to the next compared to the MJF process. Even lower layer cohesion was indeed observed for the SLS-printed thermoplastic composite material samples. It should be noted that the performance of the MJF reference is exceptional compared to that of the SLS reference.

[0272] The table above summarizes the tensile properties tested in the vertical Z direction. The values ​​are based on three repetitions. For comparison, two reference TPU powders for SLS and MJF printing are given (provided by the applicant).

[0273] [Tablesl2] Œ max (X / Y) [MP a] St. Dev. [MPa] (X / Y) [MP a] St. Dev. [MPa] E(X / Y) [MPa] St. Dev. [MPa] Eb (X / Y )[%] St. Dev. [%] SLS_M YC1 - - - - - - - - SLS_M YC2 1.51 0.47 ±31.0% 1.51 0.47 ±31.0% - - 7.4 1.5 ±20.3% SLS_OK 1.26 0.34 ±26.8% 1.26 0.34 ±26.8% - - 10.0 6.5 ±26.8% TPU Supplier r2SLS 4 0.2 + 5% - - 16 2+15% TPU Supplier rlMJF 7 1 + 18% - - - - 55 22 +40%

[0274] In [Fig.18] the main tensile properties of SLS_MYC2 and SLS_OK printed in the Z direction are shown. The tensile strength is represented by dense hatching. The tests were carried out in four copies. Two reference powders are given as examples. The tensile strength corresponds to the left axis, the elongation at break to the right axis.

[0275] Effect of laser speed: [Fig. 19] highlights the lack of effects of changing the laser speed on the tensile properties. The tested samples included SLS_MYC2 printed at a laser speed of 450 mm / s (S2) and 250 mm / s (S3). Young's modulus is represented by light hatching while tensile strength is represented by dense hatching. The standard deviation was also similar for both samples. Although the test samples printed at 250 mm / s exhibited better visual aesthetics and sintering, the mechanical properties were not affected. A significant change in the sintering behavior and thus the mechanical properties is, however, expected by changing the laser power.

[0276] Shore hardness of the printed sample: Shore A and D hardness measurements revealed once again that the mechanical properties of all samples were similar despite changes in laser speed or powder composition. The results obtained were slightly lower than the Shore A hardness indicated in the BASF Ultrasint powder datasheet (approximately 85 vs. 88-90 A). The addition of bio-based fillers generally slightly increases the Shore hardness of an unfilled thermoplastic. The opposite trend observed in this experiment may be related to the processing method used for printing.

[0277] The table above summarizes Shore A and D hardnesses as a function of powder composition and laser speed.

[0278] [Tablesl3] Laser speed Powder Shore A Shore D 450 mm / s SLS_MYC1 85 29 SLS_MYC2 85 31 SLS_OK 84 28 650 mm / s SLS_MYC1 81 28 250 mm / s SLS_MYC2 85 30

[0279] Conclusions and perspectives

[0280] These tests successfully demonstrate that it is possible to use thermoplastic composite materials according to the invention based on mycelium for SLS printing, which represents a significant advance in the field of biocomposite printing. The inability of TPU Ultrasint 88A, a pure white powder from BASF, to sinter due to inadequate interaction with the laser beam of the SLS printer was effectively resolved by incorporating 10% by weight of bio-based fillers such as mycelium powder or olive pit powder. This strategy made it possible to generate sufficient heat for sintering of the particles and to improve the sustainability quotient of the powder thanks to the increase in the bio-based content.

[0281] Although the addition of bio-based fillers resulted in a significant reduction in the elongation at break of the printed samples compared to the data sheet, the mechanical properties obtained were comparable to the data provided by the applicant for SLS printing, which confirms the viability of this approach. The MJF printing process, with its superior sintering capabilities, particularly with respect to layer orientation, offers a potential route to overcome the observed limitations in tensile strength and elongation at break in the Z direction.

[0282] The introduction of 10% by weight of bio-based fillers did not significantly change the color of the powder, suggesting compatibility with the MJF printing process, which generally requires a white powder.

[0283] The differences in material properties observed between the two types of mycelium powders, MYC1 and MYC2, and the composite samples of OK olive pits highlight the impact of particle size and homogeneity of powder mixtures on the quality of the final product, as we have seen in the test results of previous reports.

[0284] By analogy, it appears possible to minimize or replace the virgin TPU content by using alternative materials such as pure alginate, starch or mycelium powder, possibly in combination. Mixed with plasticizers or a small percentage (5-40%) of thermoplastic resin, these base materials can create a powder bed suitable for MJF printing.

[0285] Although described through a number of examples, variants and embodiments, the thermoplastic composite material according to the invention and the method of manufacturing an article therefrom include various variants, modifications and improvements which will be obvious to those skilled in the art, it being understood that these variations, modifications and improvements are part of the scope of the invention.

Claims

Claims

1. Thermoplastic composite material consisting of at least 90% by weight of a mixture of a thermoplastic matrix and a bio-sourced filler, the bio-sourced filler being composed of one or more powdered bio-sourced materials and the thermoplastic composite material being in the form of a powder.

2. Thermoplastic composite material according to claim 1, characterized in that the bio-sourced filler mainly comprises powdered mycelium, powdered walnut shell, powdered olive kernel, powdered cellulose nanofiber, powdered starch, powdered alginate, powdered carbon black or a mixture thereof.

3. Thermoplastic composite material according to claim 1 or 2, characterized in that its particle size is such that 50% or more of the grains in number have a diameter strictly less than 32 pm and in that 50% or less of the grains in number have a diameter between 32 and 63 pm.

4. Thermoplastic composite material according to claim 1 or 2, characterized in that its particle size is such that D10 = 20 pm, D50 = 70 pm and D90 = 140 pm, preferably such that D10 = 10 pm, D50 = 30 pm and D90 = 70 pm.

5. Thermoplastic composite material according to any one of the preceding claims, characterized in that the thermoplastic matrix is ​​composed of one or more thermoplastic polymers of petrochemical or biosourced origin.

6. Thermoplastic composite material according to the preceding claim, characterized in that the thermoplastic polymer is chosen from the following polymers and their mixture: thermoplastic elastomers (TPE), thermoplastic polyurethanes (TPU), thermoplastic polyamides (PA), thermoplastic polyesters, thermoplastic starches (TPS), thermoplastic vinyl polymers, thermoplastic polyolefins, thermoplastic polyacrylates and thermoplastic polyacetals.

7. Thermoplastic composite material according to any one of the preceding claims, characterized in that it comprises from 5 to 40% by weight, preferably from 10 to 20% by weight, of bio-sourced filler.

8. Thermoplastic composite material according to any one of the preceding claims, characterized in that it comprises from 30 to 95% by weight, preferably from 60 to 90% by weight, of thermoplastic matrix.

9. Thermoplastic composite material according to any one of the preceding claims, characterized in that in addition to a bio-sourced filler and a thermoplastic matrix, it further comprises from 0 to 10% by weight, preferably from 0 to 5% by weight, of at least one additive.

10. Thermoplastic composite material according to the preceding claim, characterized in that at least one additive is chosen from the list consisting of colorants, flame retardants, bonding agents, finishing agents, detailing agents, plasticizers, coupling agents, thermal stabilizers, thermal control agents, melting inhibitors, UV stabilizers, lubricants, nucleating agents, solvents, compatibilizers, prepolymers, chain extenders, crosslinking agents, catalysts, fluidizers, surface modifiers and additives intended to improve laser absorption.

11. Thermoplastic composite material according to any one of the preceding claims, characterized in that it has the following formulation: - from 10 to 40% by weight, preferably from 15 to 25%, of bio-sourced filler, and - from 50 to 95% by weight, preferably from 75% to 90%, of thermoplastic matrix.

12. Thermoplastic composite material according to any one of claims 1 to 9, characterized in that it has the following formulation: - from 5 to 20% by weight, preferably from 10 to 15%, of bio-sourced filler, - from 75 to 95% by weight, preferably from 85 to 95%, of thermoplastic matrix, and - from 0 to 10% by weight of at least one additive.

13. Thermoplastic composite material according to the preceding claim, characterized in that the thermoplastic matrix is composed of one or more thermoplastic polymers chosen from the following polymers and their mixture: polyamide 11 (PAU), polyamide 12 (PA12), polystyrene (PS), thermoplastic elastomers (TPE), polyetherimide (PEI), polyetherimide (PEI), polyethersulfones (PESU) and polymers of the polyaryletherketone family (PAEK).

14. A method of manufacturing an article from a thermoplastic composite material, characterized in that the article is manufactured by injection molding or by additive manufacturing from a thermoplastic composite material according to any one of the preceding claims.

15. Method according to the preceding claim, characterized in that the article is manufactured by additive manufacturing using 3D powder bed printing technology.

16. Method according to the preceding claim, characterized in that the 3D printing technology is a multi-jet fusion (MJF) technology or a selective laser sintering (SLS) technology.

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