Powdered thermoplastic composite material comprising a bio-based filler

Abstract

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-based filler, the bio-based filler being composed of one or more powdered bio-based 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 in that 34.4% of the grains (by number) have a diameter of between 32 and 63 μm. According to another example, the particle size of said thermoplastic composite material is such that D10 = 20 μm, D50 = 70 μm and D90 = 140 μm, preferentially such that D10 = 10 μm, D50 = 30 μm and D90 = 70 μm. The bio-based filler predominantly comprises powdered mycelium, powdered walnut shell, powdered olive pit, powdered cellulose nanofiber, powdered starch, powdered alginate, powdered carbon black, or a mixture thereof.

Description

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 plastics obtained from fossil resources with bio-sourced materials, i.e. 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 also being suitable for manufacturing an item by 3D printing and / or injection molding.

[0004] Thermoplastic composite material is herein understood to mean 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 strengthen 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 offers a solution to the problems mentioned above, by providing a powdered thermoplastic composite material combining a thermoplastic polymer and a bio-based 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 this application, bio-sourced material means a material derived from biomass, and biomass means all renewable organic matter of plant, fungal or animal origin, such as, for example, organic plant waste, wood, branches and firewood, processing waste from the agri-food or wood industry, waste and rejects from livestock farming, residues from agricultural or forestry activities, waste from the agri-food industry specialising 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 depending on the nature particular thermoplastic composite material.

[0010] It should be noted that virtually all 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 across 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 bio-sourced filler, i.e. derived from renewable, non-polluting and inexpensive organic materials, not only reduces the cost of the thermoplastic composite material, but also reduces 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 that 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 olive kernel, powdered alginate or a mixture thereof. Among these, powdered mycelium and powdered olive kernel are preferred.

[0015] These bio-sourced materials are indeed advantageous in that they are inexpensive, usually biodegradable, and can come from an environmentally friendly production chain, 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 maintains its integrity during the laser sintering or heating process.

[0018] When intended for use in SLS or MJF 3D printing, these bio-based 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 bonding agents in MJF, allowing for lighter color 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, thus reducing the risk of warping or deterioration.

[0020] In the case of MJF printing, the bio-based 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 production, lack of by-products, and numerous potential applications. In addition, it is biodegradable and can be grown locally. Using mycelium supports sustainable practices because 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 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 casting 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 mycelium can react selectively with certain resins or modifiers, particularly those used as binding agents, which allows the properties of the materials to be customized, adapting to the specific needs of the final application.

[0026] Due to its varied composition, mycelium can be engineered 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. ladder.

[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.

[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 exhibit superior thermal stability, making them ideal for high-temperature environments, particularly 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 offer 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 pit powder can be combined with other materials to create composites with properties tailored to specific applications in SLS / MJF printing, such as improved thermal resistance or customized mechanical characteristics.

[0040] For injection molding or additive manufacturing, incorporating 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 environmental responsibility.

[0041] In summary, the high thermal stability, high density, inert behavior, durability, availability, and potential for property improvement 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 nanofibrillated 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] NFC's exceptional strength and stiffness improve 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 strength, such as in the field of optoelectronics. In addition, it is ideal 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 an 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 light exposure is done using a projector (as opposed to the selective laser beam in SLS printing).

[0053] Carbon black, better known as soot, is also an advantageous bio-based filler. For example, it can be obtained from many waste materials, such as coconut shells, for example, notably by calcination, which makes it possible to recover waste, particularly from the food industry. Due to its black color, this type of bio-based filler cannot 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 bio-based filler does not comprise nanocellulose, wood powder, starch, carbon black or powdered walnut shell.

[0055] 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 pm and such that 50% or less of the grains (by number) have a diameter between 32 and 63 pm.

[0056] Such a granulometry has the particular advantage of being able to use the thermoplastic composite material according to the invention 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 when it includes a bio-sourced filler.

[0057] This specific particle size, chosen from a very wide range of possible particle sizes, both for the thermoplastic matrix and for the bio-based filler, is preferred for its overall performance when using the thermoplastic composite material for additive manufacturing and for injection molding. This particle size is not the result of an arbitrary choice, nor of simple trials, but of in-depth research validated by numerous tests.

[0058] 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.

[0059] These particle sizes are advantageous in that, when used in additive manufacturing For 3D printing and injection molding, there is no need to modify the equipment usually used to implement these manufacturing processes.

[0060] These particle sizes allow, in particular, good homogeneity of the mixture. Indeed, when the particle size (and density) of the bio-based filler matches that of the thermoplastic resin powder, the homogeneity and packing behavior of the powder bed are improved, resulting in better printing quality. In the case of injection molding, where the molten material is mixed using a screw to achieve a certain homogeneity, a homogeneous particle size distribution in the bio-based filler is less essential.

[0061] These particle sizes, corresponding to grains sized according to an optimal particle range, advantageously improve the fluidity and spreadability 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.

[0062] Particle size and distribution are particularly critical for SLS / MJF printing. Generally, a narrow particle size distribution in the range of 20 to 100 pm is preferred because this size range allows for efficient particle compaction and melting / sintering.

[0063] According to one aspect of the invention, the thermoplastic matrix is ​​composed of one or more thermoplastic polymers of petrochemical or bio-sourced origin. Indeed, the use of a thermoplastic polymer is particularly well suited to additive manufacturing and injection molding. The use of bio-sourced thermoplastic polymer is advantageous in that it makes it possible to further reduce the overall environmental and ecological impact of the composite material.

[0064] According to another aspect of the invention, a 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.

[0065] Among the thermoplastic polyamides (PA), it is advantageous to use PA 11 and / or PA 6-10 which can be biosourced.

[0066] Among the thermoplastic polyesters, 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 can be advantageously used.

[0067] It should be noted that the thermoplastic starch in the thermoplastic matrix and the powdered starch in the bio-based filler can be the same material. While in the thermoplastic matrix, the starch is plasticized and used as a bio-based filler, pure virgin starch can be used as a bio-based filler.

[0068] TPUs are preferred because they have a unique combination of properties that make them 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.

[0069] 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 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.

[0070] 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. Likewise, TPU properties can be modified during the manufacturing process, allowing for different levels of hardness and flexibility. This customization means TPUs can be tailored to specific application requirements. Additionally, some TPUs can be biocompatible, making them safe for use in medical devices that come into contact with skin or other tissues.

[0071] Due to these advantages, TPUs are 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.

[0072] Polyamides (PA) or nylons (e.g. PA6, PA66) are preferred for their toughness and temperature resistance. PA11, for example, can be produced from castor oil and is a renewable alternative to fossil polyamides.

[0073] Fossil-based polyesters, such as polyethylene terephthalate (PET), are preferred for their strength and durability. Some fossil-based but partially bio-based polyesters, such as polycaprolactone (PCL) or polybutylene adipate terephthalate (PBAT), are preferred due to their diverse properties, biodegradability, good compatibility with bio-based fillers, and commercial availability.

[0074] Bio-based polyesters, such as polylactic acid (PLA), polybutylene succinate (PBS), and polyethylene furanoate (PEF), are preferred for their high bio-based material content, good biodegradability, and mechanical strength.

[0075] Polyhydroxyalkanoates (PHAs) are preferred for the possibility of their biosynthesized production, for their excellent biodegradability and for their various mechanical properties.

[0076] Thermoplastic starch (TPS) is preferred for its abundant availability, biodegradability, and compatibility with other biopolymers.

[0077] According to another aspect of the invention, the powdered thermoplastic matrix does not comprise polyaryletherketone (PAEK), cellulose acetate propionate (CAP), polybutylene succinate (PBS), polypropylene succinate (PPS), polybutylene succinate adipate (PBSA), polybutylene adipate terephthalate (PBAT), polylactic acid (PLA), polycaprolactone (PCL), polybutylene adipate (PBA), polyhydroxyalkanoate (PHA), polyhydroxybutyrate (PHB), polyethylene furanoate (PEF), polybutylene terephthalate (PBT), polybutylene succinate terephthalate (PBST), polyester containing sebacic acid and / or azelaic acid and / or dodecanedioic acid as dicarboxylic acid, alone or in combination with acid terephthalic, and any combination thereof.

[0078] 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.

[0079] The higher the bio-based filler content in the mixture, the lower the carbon footprint of the thermoplastic composite material, but a high bio-based filler content negatively impacts the adhesion of 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-based filler content is also likely to have an impact on the mechanical properties of the material, particularly on its elastic properties. Indeed, the higher the bio-based filler content, the stiffer and harder the sintered material.

[0080] 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.

[0081] According to an additional aspect of the invention, in addition to a bio-sourced filler and a thermoplastic matrix, the thermoplastic composite material further comprises up to 20% by weight, preferably up to 10% and more preferably up to 5% of at least one additive.

[0082] Indeed, articles manufactured with such formulations for 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.

[0083] 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.

[0084] According to one aspect of the invention, the thermoplastic composite material 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.

[0085] This formulation is advantageous in that it is particularly suitable for injection molding, especially when among the additives, the thermoplastic composite material mainly comprises one or more plasticizers.

[0086] It should be noted that in this formulation, the bio-sourced load can, for example, have any particle size, particularly greater than 100 μm.

[0087] According to another aspect of the invention, the thermoplastic composite material has the following formulation: from 5 to 20% by weight, preferably from 10 to 15%, of bio-sourced filler, and from 75 to 95% by weight, preferably from 85 to 95%, of thermoplastic matrix.

[0088] This formulation is advantageous in that it is particularly suitable for additive manufacturing, for example by SLS or MJF, especially when in the thermoplastic matrix, the thermoplastic composite material comprises polyurethanes, polyamides or thermoplastic polyesters.

[0089] It should be noted that in this formulation, the bio-sourced 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.

[0090] 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 (PA11), polyamide 12 (PA12), polystyrene (PS), thermoplastic elastomers (TPE), polyetherimide (PEI) polyetherimide (PEI) and polyethersulfones (PESU).

[0091] According to one aspect of the invention, this second formulation comprises at least one additive selected 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.

[0092] 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.

[0093] According to an additional aspect of the invention, in particular in MJF printing, the bio-sourced charge undergoes a chemical treatment aimed at functionalizing the particles which constitute it.

[0094] Thus, according to one aspect of the invention, the bio-sourced filler undergoes treatment by dry mixing with a hydrophobizing agent and / or with an anti-caking agent, these agents being preferentially bio-sourced.

[0095] Dry-mix treatment with a preferably bio-based hydrophobizing agent advantageously introduces reactive epoxy groups that covalently bond to the hydroxyl groups present on the surface of the bio-based filler particles, thereby improving the compatibility of the bio-based filler with the thermoplastic matrix and printability.

[0096] Dry mixing treatment with an anti-caking agent reduces caking of the bio-based filler and layer defects when using the thermoplastic composite material of the invention in additive manufacturing, which advantageously improves print quality and makes powder recycling more efficient, which increases powder recyclability and reduces material costs.

[0097] According to another aspect of the invention, a hydrophobizing agent is chosen from the list consisting of epoxidized vegetable oils, preferably epoxidized soybean oil, epoxidized linseed oil or epoxidized sunflower oil, by epoxidized fatty acids, by polyols having primary and secondary hydroxyl groups, preferably biosourced and obtained from natural oils, preferably Merginol® 207 or Merginol® 903, by esters, preferably citric acid esters such as Citrofol® BII, by polyols derived from fatty acids and metathesis products or by long-chain alcohols, such as for example octadecanol, taken alone or in a mixture.

[0098] Indeed, long-chain alcohols can absorb onto the surface of filler particles and give them a hydrophobic character. This is a simple physical method that does not require any chemical reaction.

[0099] According to a further aspect of the invention, the hydrophobization of the particles of a filler can be obtained by esterification. The hydrophobizing agent is then chosen from the list consisting of acetic anhydride, long-chain fatty acid chlorides, maleic anhydride, cyclic anhydrides and lactones, taken alone or in a mixture.

[0100] According to one aspect of the invention, a hydrophobizing agent may be a compound of the lactam family, for example Σ-caprolactam, which undergoes surface reactions to form amide bonds with the hydroxyl groups of the bio-sourced binders, which improves the hydrophobic properties and the compatibility with thermoplastic matrices.

[0101] According to another aspect of the invention, a hydrophobizing agent may be a coupling agent of the silane family, for example octyltriethoxysilane or hexyltrimethoxysilane, which forms covalent bonds with the surface hydroxyl groups of the filler introducing hydrophobic alkyl chains to the surface of the filler particles, or a compound of the alkylketene dimer (AKD) family, which reacts with the surface hydroxyl groups to form ester bonds.

[0102] According to one aspect of the invention, a hydrophobizing agent represents up to 10%, preferably up to 5% and more preferably up to 2.5% by weight of the bio-sourced filler. Indeed, a concentration of 2.5% is optimal in terms of cost while providing the desired hydrophobizing properties.

[0103] According to a further aspect of the invention, an anti-caking agent is chosen from the list consisting of powdered silica (SiO2), talc, calcium stearate, calcium carbonate, magnesium carbonate, fatty acids and their derivatives, cellulose derivatives, coatings polymers and hydrophobic silanes.

[0104] According to an additional aspect of the invention, an anti-caking agent represents up to 5%, preferably up to 2.5% and more preferably up to 1% by weight of the bio-sourced filler. Indeed, a concentration of 1% is optimal in terms of cost while providing the desired anti-caking properties.

[0105] 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.

[0106] According to one aspect of the invention, the article is manufactured by additive manufacturing using 3D powder bed printing technology.

[0107] 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.

[0108] Indeed, these technologies are advantageously suited to the use of a powdered material.

[0109] 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

[0110] The figures are presented for information purposes only and in no way limit the invention.

[0111] [Fig. 1] illustrates the results for four cyclic tensile tests carried out on tensile samples made of a thermoplastic composite material according to the invention comprising TPE and 40% mycelium.

[0112] [Fig. 2] is a histogram illustrating the evolution of the maximum stress for the tests of [Fig. 1].

[0113] [Fig. 3] is a histogram illustrating the evolution of the deformation at the maximum stress for the tests of [Fig. 1],

[0114] [Fig. 4] is a photo of tensile test samples printed by SLS with 90% Ultrasint® TPU 88A from BASF and 10% mycelium powder.

[0115] [Fig. 5] is a photo of a geometrically complex part printed by SLS with 90% Ultrasint® TPU 88A from BASF and 10% mycelium powder.

[0116] [Fig. 6] illustrates the particle size distribution of a first mycelium powder designated as Mycelium 1.

[0117] [Fig. 7] illustrates the particle size distribution of a second mycelium powder designated as Mycelium 2.

[0118] [Fig. 8] illustrates the results of a thermal characterization test for a powder comprising 100% TPU alone.

[0119] [Fig. 9] illustrates the results of a thermal characterization test for a powder comprising 90% Ultrasint® TPU 88A from BASF and 10% fine mycelium powder.

[0120] [Fig. 10] illustrates the results of a thermal characterization test for a powder comprising 90% Ultrasint® TPU 88A from BASF and 10% very fine mycelium powder.

[0121] [Fig. 11] illustrates the results of a thermal characterization test for a powder comprising 90% Ultrasint® TPU 88A from BASF and 10% olive kernel powder.

[0122] [Fig. 12] illustrates the dimensions of a test sample printed by SLS with powders according to the invention.

[0123] [Fig. 13] illustrates printing results of test samples printed by SLS at three different laser speeds with a powder comprising 90% Ultrasint® TPU 88A from BASF and 10% very fine mycelium powder.

[0124] [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],

[0125] [Fig. 15] is a side view of the test samples located on the left in [Fig. 14],

[0126] [Fig. 16] illustrates results of printing complex shaped samples by SLS with two different powders according to the invention.

[0127] [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.

[0128] [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.

[0129] [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

[0130] Unless otherwise stated, the % values ​​given in this text are percentages by weight.

[0131] 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.

[0132] 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.

[0133] 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 injection molding.

[0134] 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 μm and 63 μm.

[0135] 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 pm and such that 34.4% of the grains (by number) have a diameter between 32 pm and 63 pm.

[0136] As is well known, in the case where the particles are not spherical, the term "diameter" refers to the largest dimension of the particles. Thus, for anisotropic particles such as fibers, the diameter refers to the largest dimension of the particles.

[0137] 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.

[0138] Very conclusive tests in additive manufacturing have been obtained with a thermoplastic composite powder material with a D50 between 70 pm and 90 pm, so this particle size range is also preferred. Generally, a thermoplastic composite powder material whose particles have a diameter strictly less than 1000 pm is preferred, more preferably whose particles have a diameter between 10 pm and 70 pm.

[0139] Note that D10 is always smaller than D50 which is smaller than D90, and the closer their values ​​are, the more homogeneous the grain size.

[0140] These particle sizes were measured using analytical mechanical sieves, which provide a simple, reliable and inexpensive measurement of particle size distribution. The applicant used a vibrating sieve model AS200 marketed by Retsch, combined with various sieve sizes from Retsch ranging from 4000 μm to 63 μm according to DI N ISO 3310 / 1.

[0141] 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.

[0142] 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.

[0143] According to another embodiment, this percentage by weight of bio-sourced 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.

[0144] 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 that makes it possible to directly or indirectly recover waste or an inexpensive material derived from renewable organic materials, of plant, fungal or animal origin.

[0145] In addition to the bio-sourced filler, the composite material according to the invention may comprise a non-bio-sourced filler.

[0146] 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 articles manufactured from such a composite material.

[0147] 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.

[0148] In addition, the crushed bio-based feedstock 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 SLS / MJF technology.

[0149] The powdered mycelium used in the invention is preferably obtained from mushroom cultivation, which is a biotechnological process during which, by decomposing a feeding 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 feeding 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.

[0150] 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.

[0151] Among the mushrooms used, we can cite, for example, ganodermataceae, notably Ganoderma lucidum, oyster mushrooms, notably Pleurotus ostreatus, and polyporaceae, notably Trametes versicolor.

[0152] 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 very energetic nut, but only the fruit is usually used. The use of the shell, reduced to powder, for example by grinding, therefore makes it possible to recover this waste from the agri-food industry.

[0153] Similarly, the powdered olive kernel used in the invention is preferably obtained from olive kernels from olive farming, particularly 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.

[0154] 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 using mechanical or chemical processes. They are advantageous due to their strength, lightness, and biodegradability.

[0155] Starch is a carbohydrate found in many plants, particularly their roots, tubers, and seeds. Common sources of starch powder include corn, potatoes, wheat, rice, and cassava. Starch powder is extracted by crushing these plant parts and processing them to separate the starch.

[0156] 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 through a process that involves the use of alkaline solutions.

[0157] 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.

[0158] 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.

[0159] 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.

[0160] 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.

[0161] 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.

[0162] One of these additives may for example be chosen from colorants, flame retardants, binding agents, detailing agents, plasticizers, coupling agents, stabilizers thermal agents, UV stabilizers, lubricants, nucleating agents, compatibilizers and additives intended to improve laser absorption.

[0163] 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.

[0164] According to a first variant of the invention, the thermoplastic composite material has a formulation specifically adapted to injection molding.

[0165] For injection molding, the requirements are different from those for additive manufacturing and are lower. Indeed, a wide variety of combinations of thermoplastic matrix and bio-based filler are possible. The requirements mainly stem from the desired properties of the final material, such as Shore hardness, tensile strength, etc.

[0166] For injection molding, the composite material comprises 50 to 95% by weight, preferably 75 to 90%, of thermoplastic matrix.

[0167] 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 injecting a material into a cavity of a mold temporarily disposed adjacent a surface of the substrate, wherein a shape, location or thickness of the injected material on the substrate is constrained by the mold according to conventional injection molding techniques.

[0168] According to a preferred embodiment of the invention, the powdered thermoplastic composite material, in particular the bio-sourced filler, may undergo a chemical treatment aimed at functionalizing the particles that constitute it. Such a chemical treatment may, for example, be carried out by dry mixing (known by the English term DIY-blending), which process consists of dry mixing an additive with the powdered thermoplastic composite material.

[0169] According to one embodiment of the invention, the bio-sourced filler is thus treated by dry mixing with a hydrophobizing agent, which is for example chosen from the list consisting of epoxidized vegetable oils, preferably epoxidized soybean oil, epoxidized linseed oil or epoxidized sunflower oil, by epoxidized fatty acids, by polyols having primary and secondary hydroxyl groups, preferably bio-sourced and obtained from natural oils, preferably Merginol® 207 or Merginol® 903, by esters, preferably citric acid esters such as Citrofol® BII, by polyols derived from fatty acids and metathesis products or by long-chain alcohols, such as for example octadecanol, taken alone or in a mixture.

[0170] Hydrophobization of filler particles can also be achieved by esterification and the hydrophobizing agent is then chosen from the list consisting of acetic anhydride, long-chain fatty acid chlorides, maleic anhydride, cyclic anhydrides and lactones, taken alone or in mixture.

[0171] Acetic anhydride reacts with hydroxyl groups on the filler surface, forming acetyl esters that increase hydrophobicity.

[0172] Long-chain fatty acid chlorides, such as stearoyl chloride and palmitoyl chloride, react with the hydroxyl groups on the filler surface to introduce long hydrocarbon chains to the surface, which significantly enhances hydrophobicity. This method is very effective and can be controlled by varying the chain length of the fatty acid chloride.

[0173] Maleic anhydride reacts with surface hydroxyl groups on the filler, forming ester bonds while introducing double bonds as reactive sites. This has the dual advantage of increased hydrophobicity and better compatibility with polymer matrices.

[0174] Other cyclic anhydrides, e.g., succinic anhydride and phthalic anhydride, can be used for similar reactions with surface hydroxyl groups of the filler, forming hydrophobic esters.

[0175] Lactones, e.g., γ-Butyrolactone and 5-Valerolactone, react with hydroxyl groups on the filler surface to create ester bonds, imparting hydrophobicity to the surface.

[0176] According to one embodiment of the invention, a hydrophobizing agent may also be a compound from the lactam family, for example Σ-caprolactam, which forms amide bonds with the hydroxyl groups of the bio-sourced binders.

[0177] Finally, according to another embodiment of the invention, a hydrophobizing agent may be a coupling agent from the silane family, for example octyltriethoxysilane or hexyltrimethoxysilane, or a compound from the alkylketene dimer (AKD) family.

[0178] Hydrophobization of a filler, such as olive pit powder or other powder, can be achieved through various chemical modification techniques. These include epoxidation, anhydride modification, lactone and lactam reactions, coupling with fatty acid chlorides, and esterification with acetic anhydride or long-chain fatty acids. Each of these methods imparts hydrophobic properties by modifying the surface chemistry of the particles, which improves compatibility with polymer matrices and fluidity in additive manufacturing processes such as SLS and MJF.

[0179] Tests have shown that covalent surface modifications outperform simple impregnation methods. Methods that establish ester, amide, and ether bonds—for example, via anhydrides, fatty acid chlorides, and lactams—have demonstrated superior performance. These covalent modifications result in a more durable and stable hydrophobic coating, ensuring better moisture resistance, improved powder flow, better compatibility with thermoplastic matrices, and greater consistency in print quality for SLS and MJF processes.

[0180] It is important to note that covalent bonding alters the biodegradation properties of the fillers, with the surface becoming more hydrophobic and less susceptible to microbial attack or hydrolysis. However, if the goal is to improve recyclability rather than biodegradability, this change is not considered a major disadvantage. On the contrary, the improved stability of the filler in humid environments allows for better reuse of the powder in multi-cycle printing operations, resulting in improved durability for the invention.

[0181] Preferably, a hydrophobizing agent represents up to 10%, preferably up to 5% and more preferably up to 2.5% by weight of the biosourced filler.

[0182] In one exemplary embodiment, a bio-based filler consisted of 95% by weight of olive kernel powder, which was treated with 5% by weight of epoxidized soybean oil (ESBO). ESBO is a bio-based plasticizer and stabilizer that serves as a hydrophobizing agent for the bio-based filler. It introduces reactive epoxy groups that can covalently bond to the hydroxyl groups on the surface of the olive kernel particles, thus improving compatibility with the thermoplastic matrix and printability. Tests carried out with this bio-based filler for additive manufacturing using MJF technology (see below) have shown excellent results, with greatly improved mechanical properties compared to commercial olive kernel powders that have not been treated with ESBO.

[0183] In another exemplary embodiment, a bio-based filler consisted of 95% by weight olive kernel powder, which was treated with 5% by weight Merginol® 207 from HOBUM OLEOCHEMICALS, a bio-based polyol obtained from natural oils, having primary and secondary hydroxyl groups, and containing a high proportion of renewable raw materials. Like ESBO, Merginol® 207 is bio-based and acts as a hydrophobizing agent. However, unlike ESBO, it does not covalently bond to the surface of the olive kernel powder. Instead, it physically permeates and adheres to the particle surface, thus improving compatibility with thermoplastic polyurethanes (TPUs) and reducing moisture absorption.Tests carried out with this bio-sourced filler for additive manufacturing using MJF technology (see below) have shown excellent results, with significantly improved mechanical properties compared to commercial olive kernel powders that have not been treated with ESBO.

[0184] Although both ESBO and Merginol® 207 hydrophobize olive pit powder, ESBO offers superior performance due to the covalent bond, which results in better dispersion and a more stable powder bed during MJF printing. In these tests, ESBO-treated powders achieved a homogeneous powder bed with no component separation, while Merginol® 207-treated powders showed some signs of separation.

[0185] Since ESBO has shown very satisfactory results, the applicant also sought to improve the recyclability of the excess powder with an anti-caking agent. The purpose of such an anti-caking agent is to prevent particle agglomeration, improve flowability and maintain a uniform and fluid powder bed during MJF printing.

[0186] Indeed, powder agglomeration, or caking, occurs when fine particles adhere to each other, forming larger clumps that disrupt homogeneity. of the powder bed in MJF printing. This caking can lead to uneven layer deposition, print defects, and increased material waste. By improving powder flow, the anti-caking agent reduces caking and layer defects in the MJF printer, resulting in better print quality and more efficient powder recycling. This, in turn, increases powder recyclability and reduces material costs.

[0187] An anti-caking agent may be selected from the list consisting of powdered silica (e.g. Aerosil® or Cab-O-Sil®), talc, calcium stearate, calcium carbonate, magnesium carbonate, fatty acids and their derivatives (e.g. stearic acid or magnesium stearate), cellulose derivatives (e.g. methylcellulose or hydroxypropylmethylcellulose), polymer coatings (e.g. polyethylene glycol) and hydrophobic silanes.

[0188] To this end, the anti-caking agent physically coats the surface of the powdered filler particles, forming a barrier that reduces surface energy, van der Waals forces, and electrostatic attractions between particles. It can also provide a lubricating layer on the particles or act as particle spacers, reducing adhesion between particles. This prevents particle agglomeration, maintains a free-flowing powder, and promotes a homogeneous powder bed, particularly in MJF printing.

[0189] Tests indicated that 1% of anti-caking agent would appear to be sufficient to reduce caking. The applicant used larger amounts to achieve a more pronounced effect.

[0190] Preferably, an anti-caking agent represents up to 5%, preferably up to 2.5% and more preferably up to 1% by weight of the bio-sourced filler.

[0191] It can be observed that some anti-caking agents can also serve as hydrophobizing agents. For example, surface-modified silicas (e.g., silanized or organofunctionalized silicas) can impart hydrophobicity while continuing to act as effective anti-caking agents. Similarly, fatty acid-coated talc or other hydrophobic anti-caking agents can play a dual role. Thus, a smart combination of hydrophobes and anti-caking agents leads to an optimized formulation, achieving both moisture resistance and improved powder flow. Such a strategy would improve the overall performance and printability of fillers, particularly for SLS and MJF, thus promoting the reuse and recyclability of materials in additive manufacturing.

[0192] Thus, in an exemplary embodiment, a bio-sourced filler consisted of 95% by weight of olive kernel powder, which was treated with 2.5% by weight of ESBO and 2.5% by weight of anti-caking agent in the form of silica powder (SiCh), with a particle size such that the maximum average particle diameter is 60 μm. Indeed, this particle size is suitable for additive manufacturing processes such as SLS and MJF, where the particle size is preferably between 20 and 100 μm, but particle sizes close to 60 μm are preferable for better packing density, better sintering behavior and better surface finish quality.

[0193] Tests carried out with this bio-sourced filler for additive manufacturing using MJF technology (see below) have shown excellent results, with mechanical properties still significantly improved compared to commercial olive kernel powders that have not been treated with ESBO and silica.

[0194] In addition to the comparative tests mentioned here, olive kernel powder treated with ESBO alone or with ESBO and silica was analyzed by infrared spectroscopy and contact angle measurement.

[0195] Infrared (IR) spectroscopy was used to identify and characterize the functional groups and chemical bonds of ESBO and Merginol® 207-treated olive kernel powder and compare it to untreated olive kernel powder. By measuring the absorbance of infrared light at specific wavelengths, this technique allowed the detection of covalent bonds by the appearance of specific absorption bands, such as C=O stretching (ester carbonyl) and CH stretching (methyl / methylene), which confirmed successful covalent bonding of ESBO and Merginol® 207 to the surface of the olive kernel powder. For this purpose, the powder was dried at 100°C for 3.5 hours to remove moisture, and 5-10 mg of each powder was tested with a Thermo Scientific™ Nicolet™ iS™5 Fourier Transform Infrared (FTIR) spectrometer (Attenuated Total Reflection (ATR) mode, wavenumber 4000 cm1 at 400 cm 1 , resolution 4 cm 1 , 32 scans per sample).

[0196] Drop Shape Analysis (DSA) measures the contact angle of a liquid droplet on a solid surface, which reflects the wettability of a material. DSA was used to assess the hydrophobicity of modified olive pit powders and confirm their successful hydrophobization with ESBO and Merginol® 207. Indeed, the presence of anti-caking agents such as silica can also affect surface properties, which can be quantified by DSA. The tests carried out confirmed the modification of the surface hydrophobicity of the bio-based powder and assessed the success of the surface modification. Higher contact angles for the ESBO-treated powder suggest effective hydrophobization, while Merginol® 207 gave more moderate results.DSA was performed with a Krüss DSA 100E drop shape analyzer (3D printed mold with specific dimensions is used to create a flat and uniform powder surface for DSA measurements, 5 pL deionized water droplets).

[0197] 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.

[0198] 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 thanks to the use of dark-colored bonding agents and can achieve smoother, more detailed surface finishes. BJ3DP technology is very similar to MJF, except that the detailing agent is missing.

[0199] Although all three techniques use thermoplastic base materials, the presence By combining 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.

[0200] 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.

[0201] 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.

[0202] 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.

[0203] Selective laser sintering (SLS) is a 3D printing process based on liquid-free selective laser sintering, where layers of powder are sintered or fused layer by layer using laser energy.

[0204] SLS printing mainly uses fine thermoplastic powders. Thus, the particle size of the thermoplastic composite material for SLS printing preferably ranges from 20 to 100 micrometers, with the uniform particle size ensuring uniform sintering and high-quality printing resolution.

[0205] 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.

[0206] Among these polymers, those with a melting point above 300°C are more preferably preferred.

[0207] 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.

[0208] For SLS printing, the preferred bio-based fillers are powdered starch, powdered NFC, powdered mycelium and powdered olive kernels, in an amount representing 10 to 20% by weight, preferably 5 to 15%, of bio-based filler by weight in the thermoplastic composite material.

[0209] The table below gives examples of complete compositions of the composite material according to the invention intended for SLS printing.

[0210] [Table 1]

[0211] M JF 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.

[0212] MJF printing also uses thermoplastic powders, with particle diameters preferably between 60 and 100 μm.

[0213] 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 bonding 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.

[0214] 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 fusing the individual particles. The bonding agent is usually a black liquid, which facilitates the absorption of heat from infrared light at the voxel to be printed.

[0215] However, in the context of using bio-based fillers, some additives or components can be considered as "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 surplus powders.

[0216] A colorant is usually added to the binding agent to provide visual contrast during the printing process, facilitating quality control and inspection.

[0217] In more complex and innovative systems, additives may also include the products listed below.

[0218] 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.

[0219] Chain extenders and crosslinkers: These low molecular weight compounds react with 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.

[0220] 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.

[0221] 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.

[0222] Fluidifiers and plasticizers: To improve the flowability of the thermoplastic matrix powder, fluidizers can be added. These help to achieve a uniform layer of powder during the printing process.

[0223] Dyes or pigments: For aesthetic purposes or to differentiate materials, dyes or pigments may be added to thermoplastic matrix powders.

[0224] Compatibility agents: These are added to improve the compatibility between the different polymer components and the bio-based filler, thus ensuring a uniform sintering process.

[0225] In the case of MJF printing, a finishing agent can also be applied to the edge of the printed part before exposure to the projector light to prevent any further reaction in the powder bed and 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.

[0226] A detailing agent can be used to define the fine details and smooth surfaces of the printed object. It is usually 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 achieve high resolution and accuracy in the final print by controlling the spread of the fusing agent, the heat absorbed, and the subsequent melting and sintering of the powder. This essentially improves the fine features and accuracy of the printed parts.

[0227] A 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, resulting in better resolution of surface details, usually in combination with solvents.

[0228] The detailing agent typically consists of low-boiling solvents that absorb process heat through evaporation and act as melt inhibitors, preventing the powder from melting in areas where the part should not form, resulting in better definition and sharper edges.

[0229] Other preferred additives include surface modifiers, thermal and UV stabilizers, solvents and compatibility improvers.

[0230] A surface modifier allows you to change the characteristics of the surface of printing, such as gloss or texture, in order to achieve the desired aesthetic or functional properties.

[0231] A heat stabilizer helps ensure that the detailing agent remains effective throughout the printing process, especially at high temperatures and other harsh conditions.

[0232] 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.

[0233] A compatibility enhancer ensures that the detailing agent works harmoniously with the thermoplastic composite material powder and the bonding agent, without causing any unwanted reactions.

[0234] A plasticizer may be present in an amount representing 10 to 20% by weight of the thermoplastic composite material since some composite materials may already include such an additive.

[0235] The thermoplastic composite material may contain from 0 to 20% plasticizer and from 0 to 10% other types of additives. In fact, some thermoplastic materials used for the thermoplastic matrix may already include such additives.

[0236] The other additives may, for example, be present in an amount representing 0 to 10% by weight of the thermoplastic composite material.

[0237] Formulations for MJF printing can be designed to optimize the interaction between a detailing agent, a bonding agent, and a thermoplastic composite material powder to ensure that the final printed parts have the desired mechanical properties, accuracy, and surface finish.

[0238] The combination of a detailing agent and a bonding agent in MJF printing enables the creation of parts with complex geometries and excellent mechanical properties.

[0239] It should be noted that for MJF printing, the thermoplastic composite material according to the invention used must be compatible with the bonding agent.

[0240] 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.

[0241] For MJF printing, the thermoplastic composite material according to the invention must also have thermal properties that allow 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.

[0242] Thus, for MJF printing, preferred materials for the thermoplastic matrix according to the invention include in particular polyamides (PA), for example such as polyamide 11 (PA11) or polyamide 12 (PA12), thermoplastic polyurethanes (TPU), other modified thermoplastics or a mixture thereof.

[0243] For MJF printing, preferred bio-based fillers are powdered starch, powdered NFC, powdered mycelium, and powdered olive kernels, in an amount representing, for example, about 10% by weight of the mixture of a thermoplastic matrix and a bio-based filler.

[0244] The table below gives examples of complete compositions of the composite material according to the invention intended for MJF printing.

[0245] [Table 2]

[0246] We see that these compositions are the same as for SLS printing.

[0247] It should 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 and as a thermoplastic matrix.

[0248] 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.

[0249] [Table 3]

[0250] These compositions have given excellent results when the binding agent is epichlorohydrin, glutaraldehyde, glyoxal or aqueous citric acid with a black pigment.

[0251] 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 for manufacturing. Tl flexible and / or stretchable articles, including inflatable articles.

[0252] The invention also relates to a method of manufacturing an article from a thermoplastic composite material as described above.

[0253] 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.

[0254] 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 the implementation of a 3D printing technology, preferably a 3D printing technology on a powder bed, more preferably carried out by SLS or MJF.

[0255] 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.

[0256] Tests

[0257] 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 having satisfactory mechanical and aesthetic properties. While the injection molding technology does not represent any particular technical complexity, the tests are also intended 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.

[0258] Tensile strength tests (PAM technology)

[0259] A first series of tests to validate the tensile strength properties was carried out according to the DI N 53504 standard 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 (PAM), a technique halfway between 3D printing and injection molding, which therefore allows the feasibility of both 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. Alternatively, direct pellet extrusion (FGF) technology could have been used.

[0260] [Table 4]

[0261] In sample A, the TPE is a proprietary matrix of the KUORI company, while the mycelium comes from two external deposits.

[0262] In samples D and E, MYC1 indicates a first mycelium powder called “fine”, whose particle size distribution is given in [Fig. 6], while MYC2 indicates a second mycelium powder called “very fine”, whose particle size distribution is given in [Fig. 7].

[0263] The table below gives the particle sizes of bio-based fillers used in combination with Ultrasint® 88A TPU for SLS printing.

[0264] [Table 5]

[0265] 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.

[0266] [Table 6]

[0267] The tensile samples are all in the form of standardized flat specimens (see [Fig. 4] and [Fig. 12]). For the tests, three to four samples from each family were tested.

[0268] The SLS-printed tensile samples were printed in a horizontal X / Y orientation.

[0269] 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.

[0270] Cyclic tensile tests with increasing nominal strain were performed, 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.

[0271] The results of these tests are illustrated in [Fig. 1] for tensile specimen A.

[0272] Maximum stress deformation tests

[0273] A second series of tests to validate the maximum stress and strain at maximum stress was carried out on standard tensile specimens A, B and C.

[0274] 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 mean of the four samples and the error bars are related to the batch standard deviation.

[0275] [Table 7]

[0276] From these results, it can be inferred 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.

[0277] The advantage of MJF printing over SLS printing is also highlighted, reflected in better layer adhesion and generally superior properties in the Z direction for MJF.

[0278] Particularly for thermoplastic composite materials, material drawbacks related to layer orientation can be eliminated thanks to the advanced fusion properties of MJF printing.

[0279] 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.

[0280] It should also be noted that no significant differences between samples of the same family were identified, we can deduce that the behavior is reproducible given the technology used to print the samples.

[0281] 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.

[0282] Further tests described below were carried out using SLS technology by KUORI.

[0283] One of the goals 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.

[0284] The results should help to outline the potential for possible transfer or reproduction with MJF technology and to further explore the possibilities of transfer and reproduction with MJF technology.

[0285] Thermal characterization tests

[0286] 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.

[0287] The following thermal profile was used for the measurements:

[0288] - 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.

[0289] - Step 2: Gradual cooling at 10°C / min from 200°C to 0°C in a nitrogen atmosphere.

[0290] - Step 3: Incremental heating at 10°C / min from 0°C to 200°C in an atmosphere of nitrogen.

[0291] 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.

[0292] 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 unchanged. The enthalpies of fusion also remain virtually 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 data sheet, 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.

[0293] Production of samples by SLS printing

[0294] The samples were printed using an SLS S1 printer from Sintratec, Switzerland (laser = 2.3W, λ = 445 nm), with a maximum printed object volume of 3.04 dm 3 (130 mm x 130 mm x 180 mm). All samples were sandblasted (Micropeen 950 ZPD, lepco Switzerland) to remove unsintered powder.

[0295] 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],

[0296] The appearance of these powders is given in the table below:

[0297] [Table 8]

[0298] In preliminary experiments, pure TPU Ultrasi nt® 88A powder was used for printing. However, no interaction was observed between the laser beam and the powder, hence the absence of sintering. On the contrary, with increasing temperature, a molten block formed. This phenomenon is probably attributable to the white coloring of the powder, which leads to insufficient absorption at the laser wavelength, combined with the relatively low laser power. Sintratec S1 (2.3 W).

[0299] 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:

[0300] [Table 9]

[0301] Effect of printing temperature: At a printing temperature of 125.7 °C (method S1), 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.

[0302] 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.

[0303] 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 SLSJDK powders, probably due to the broader particle size distribution of the MYC1 powder.

[0304] Printing complex hollow shapes

[0305] Compared to the more traditional 3D printing technique Fused Deposition Modeling (FDM), SLS printing makes it easy to fabricate hollow surfaces that typically require a support structure. 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 SLSJDK (family F) powders due to their superior performance. Initial attempts with the S2 method proved difficult due to the presence of powder. compact 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.

[0306] [Table 10]

[0307] Mechanical properties

[0308] The mechanical properties of the test samples were tested by tensile measurements over three repetitions. The maximum stress (a max), the breaking stress (Ob), the elongation at break (&>), as well as an approximation of the Young's modulus (E) were extracted from the stress-strain curves.

[0309] As shown in the table below and [Fig. 17], the tensile properties are within 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 BASF's Ultrasint® 88A TPU, the produced samples have a lower elongation at break, but a similar tensile strength and a higher modulus. Similar results were observed for KUORI's 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 relies on a different sintering method. Nevertheless, the improved Z- properties resulting from the MJF process promise to compensate for the limitations encountered when using higher ratios of bio-based fillers.

[0310] [Table 11]

[0311] In [Fig. 17] the main tensile properties of the three SLS powders printed with the S2 method are shown in the horizontal X / Y plane. 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. Tensile strength and elastic modulus correspond to the left axis, elongation at break corresponds to the right axis.

[0312] 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 recommended.

[0313] 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 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 is worth noting that the performance of the MJF reference is exceptional compared to that of the SLS reference.

[0314] The table below 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).

[0315] [Table 12]

[0316] In [Fig. 18] the main tensile properties of SLS_MYC2 and SLSJDK printed in the Z direction are shown. Tensile strength is represented by dense hatching. The tests were carried out in quadruplicate. Two reference powders are given as examples. Tensile strength corresponds to the left axis, elongation at break to the right axis.

[0317] 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 the 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.

[0318] Shore hardness of the printed sample: Shore A and D hardness measurements once again revealed 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 data sheet (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.

[0319] The table below summarizes Shore A and D hardnesses depending on powder composition and laser speed.

[0320] [Table 13]

[0321] Comparative tests in MJF printing

[0322] The applicant performed comparative tests of various mechanical properties using a commercial powder and two powders according to the invention. The commercial powder used is Ultrasint® TPU01, which is a thermoplastic polyurethane suitable for MJF printing and manufactured by BASF. Formulation G1 is a powder according to the invention comprising 90% by weight of Ultrasint® TPU01 and 10% olive kernel powder. Formulation G1 is a powder according to the invention comprising 90% by weight of Ultrasint® TPU01 and 10% by weight of a filler comprising 95% by weight of olive kernel powder and 5% by weight of epoxidized soybean oil (ESBO). The ESBO used is Vikoflex® 7040 from Cargill. The MJF-printed tensile samples were printed in a horizontal X / Y orientation.

[0323] In these formulations, the particle size of the olive kernel powder announced by the manufacturer is such that D10 = 11 μm, D50 = 57 μm and D90 = 95 μm, with approximately 72% by weight of the grains having a diameter between 63 and 125 μm and approximately 20% by weight of the grains having a diameter strictly less than 63 μm. This particle size is however likely to deviate slightly from these values.

[0324] The table below summarizes the following values ​​measured for these three formulations, as well as their comparison: Maximum stress a max : This is the maximum mechanical stress (a = F / Ao) reached by a material before entering the unstable plastic deformation phase. It is expressed in megapascals (MPa). It is measured using a uniaxial tensile test (ISO 527 or ASTM D638 standards). The maximum axial force F max is recorded by high-precision force sensors. The maximum stress is obtained by dividing this force by the initial cross-sectional area Ao of the specimen. The result is extracted from the peak of the stress-strain curve. Maximum nominal deformation £ ma xnom (%): This is the nominal longitudinal strain (£nom = AL / Lo x 100) corresponding to the point of maximum stress (a max ), expressed as a percentage. The measurement is carried out by monitoring the relative displacement of the jaws of the tensile machine. The data comes from integrated displacement sensors or contact extensometers. Accuracy may be limited due to the location of plastic deformations (necking). Maximum actual deformation £ maxvid (%): This is the actual local strain measured at the point of maximum stress, determined using optical tracking, expressed as a percentage. It includes necking phenomena. It is measured by a digital image correlation system. Contrast patterns (paint or markings) are applied to the surface of the sample. The cameras record local deformations in real time by tracking the displacements of the patterns. This method makes it possible to calculate deformation fields with micrometric resolution. Ultimate stress capture: This is the mechanical stress calculated just before the specimen completely breaks. It is expressed in megapascals. It is measured by a uniaxial tensile test. The ultimate force F ru capture is measured just before the total loss of continuity of the material, and capture is calculated as follows: capture = F rupture / Ao. The initial section Ao is used, although the necking modifies the local geometry at the end of the test. Nominal elongation at break £ ru pturenom: This is the total nominal longitudinal elongation of the specimen at the time of rupture, expressed as a percentage. It is calculated as follows: £ru P turenom = AL / Lo x 100. Its measurement is based on the displacement of the jaws of the tensile machine. An extensometer is used to accurately measure the nominal strain. However, this method may underestimate or overestimate the actual strain in necking areas. Actual elongation at break £ rupturevid: This is the actual elongation at break, expressed as a percentage, which is measured locally in the areas where necking has occurred, taking into account the actual geometry and strain gradients. Its measurement is carried out using video tracking via digital image correlation. The strain fields are calculated in real time, allowing for precise measurement of the strain in critical regions up to breakage. Tensile modulus E: It is the elastic modulus measured in the linear phase of the stress-strain curve, representing the intrinsic stiffness of the material in tension, expressed in megapascals. For its measurement, during the tensile test, the initial slope of the stress-strain curve is determined in the elastic region (E = AO / AE). The use of a high-resolution extensometer or a video tracking system via digital image correlation is crucial to capture small elastic deformations. Standards (ISO 37) define the admissible deformation range for the calculation of E.

[0325] ISO 37 was used for tensile tests. The test specimens were stretched along their longitudinal axis.

[0326] [Table 14]

[0327] In general, it is observed that the mechanical properties are preserved and satisfactory, whether with the powder according to the commercial formulation or with the powder according to the G1 formulation, with a notable improvement in the tensile modulus, the maximum actual strain and the actual elongation at break with the G1 formulation. Therefore, the addition of 10% by weight of olive kernel powder as a filler in the polymer does not lead to a reduction in the Mechanical properties. When comparing the powder according to the commercial formulation with the powder according to the G3 formulation, it is observed that the addition of a functionalizing agent to the surface of the filler, in particular epoxidized soybean oil (ESBO), significantly improves the mechanical properties. On average, an improvement of 26.21% is observed for all properties, with a more pronounced effect on the elongation at break and on the maximum stress. It can be concluded that ESBO, by covalently bonding to the filler in the form of olive pit powder, strengthens the weak interactions (such as Van der Waals interactions) with the TPU matrix, thus improving the overall performance of the thermoplastic composite material.

[0328] Conclusions and perspectives

[0329] These tests successfully demonstrate that it is possible to use thermoplastic composite materials according to the invention based on mycelium for SLS printing and for MJF printing, which represents a significant advance in the field of biocomposite printing.

[0330] The inability of BASF's pure white TPU Ultrasint® 88A powder to sinter due to inadequate interaction with the SLS printer's laser beam was effectively addressed by incorporating 10% by weight of bio-based fillers such as mycelium powder or olive pit powder. This strategy generated sufficient heat for particle sintering and improved the powder's sustainability quotient through increased bio-based content.

[0331] Although the addition of bio-based fillers resulted in a notable 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, confirming the viability of this approach. The MJF printing process, with its superior sintering capabilities, particularly regarding layer orientation, offers a potential route to overcome the observed limitations in tensile strength and elongation at break in the Z direction.

[0332] 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.

[0333] 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.

[0334] 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.

[0335] Tests carried out with TPU and a bio-based filler based on olive pits for additive manufacturing using MJF technology show excellent results, with mechanical properties significantly improved compared to TPU powders, and even more improved when the bio-based filler based on olive pits was treated with ESBO.

[0336] Although described through a number of examples, variations and embodiments, the thermoplastic composite material according to the invention and the method of manufacturing an article therefrom include various variations, 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, the particle size of these powders being such that 50% or more of the grains by number have a diameter strictly less than 32 μm and in that 50% or less of the grains by number have a diameter of between 32 and 63 μm.

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

3. 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.

4. 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.

5. Thermoplastic composite material according to the preceding claim, characterized in that a 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.

6. 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.

7. 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.

8. 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 up to 10% by weight, preferably up to 5% by weight, of at least one additive.

9. 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.

10. 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.

11. Thermoplastic composite material according to any one of claims 1 to 8, characterized in that it has the following formulation: - from 5 to 20% by weight, preferably from 10 to 15%, of bio-sourced filler, and - from 75 to 95% by weight, preferably from 85 to 95%, of thermoplastic matrix.

12. 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 (PA11), polyamide 12 (PA12), polystyrene (PS), thermoplastic elastomers (TPE), polyetherimide (PEI) polyetherimide (PEI) and polyethersulfones (PESU).

13. 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.

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

15. 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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