Thermoplastic composite powder material containing a bio-based filler

Abstract

A thermoplastic composite powder material comprising a bio-based filler. One aspect of the invention relates to a thermoplastic composite powder 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 bio-based materials in powder form. The particle size distribution 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 34.4% of the grains (by number) have a diameter between 32 and 63 µm. According to another example, its particle size distribution is such that D10 = 20 µm, D50 = 70 µm and D90 = 140 µm, preferably such that D10 = 10 µm, D50 = 30 µm and D90 = 70 µm.The bio-based feedstock consists mainly of powdered mycelium, powdered walnut shells, powdered olive kernels, powdered cellulose nanofibers, powdered starch, powdered alginate, powdered carbon black, or a mixture thereof. Figure to be published with the abbreviation: Figure 5.

Description

Title of the invention: Thermoplastic composite powder material comprising a bio-based 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-based materials, that is to say with materials derived from renewable organic matter of plant or animal origin.

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

[0004] By thermoplastic composite material, we mean here a material composed of a thermoplastic polymer matrix, a filler, and optionally other additives, for example, modifiers and plasticizers, present in smaller percentages. The role of the filler is usually to strengthen the polymer matrix and / or 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 thermoplastic composite powder 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-based filler, the bio-based filler being composed of one or more bio-based materials in powder form and the thermoplastic composite material being in powder form.

[0007] In this application, the term "bio-based 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, and industrial processing waste. agri-food or wood, waste and discharges from livestock farming, residues from agricultural or forestry activities, waste from the agri-food industry specializing in the processing of livestock, etc.

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

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

[0010] It should be noted that virtually all particle sizes of the bio-based filler can be used, with the coarser 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 allows the entire bio-based filler powder to be used and thus fully utilized across its entire particle size range.

[0011] It should 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 petrochemical-based polymer by a bio-based filler, i.e. 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 should be noted that the thermoplastic composite material of the invention is advantageously recyclable or reusable. For example, in printing by multi-jet fusion (MJF) or selective laser sintering (SLS) technology, the powder that is neither sintered nor bound can be reused in subsequent printings. Similarly, the article obtained from the thermoplastic composite material of the invention is also recyclable.

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

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

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

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

[0018] When intended for use in SLS or MJF type 3D printing, these bio-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, enabling 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. Advantageously, they have a coefficient of thermal expansion that allows for controlled expansion and contraction during the printing process, thus reducing the risk of deformation 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 detrimental, for these bio-based materials, which advantageously guarantees the safety of operators and the environment when these materials are handled.

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

[0023] Other advantages of mycelium stem from its composition and inherent structure. Indeed, mycelium contains, in particular, a significant proportion of chitin which ensures its structural integrity and resistance, polysaccharides which contribute to its flexibility and resilience, and proteins, lipids and minerals such as calcium which contribute to the overall functionality of the material and its durability.

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

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

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

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

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

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

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

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

[0033] Walnut shells possess 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 using 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, particularly 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 the 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, particularly during composition and printing processes, ensuring compatibility with various polymers and maintaining the desired properties of the composite material.

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

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

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

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

[0043] The exceptional strength and rigidity of NFC 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 but 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 particular in improved material cohesion and superior structural integrity of printed objects.

[0046] The versatility of NFC functionalization makes it possible to adapt the properties of these materials 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 MJF molded or printed objects that require protection against gas 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, as in the field of optoelectronics. Furthermore, it is perfectly suited for MJF printing, where white powders are preferred.

[0049] Similarly, due to its ability to absorb and dampen energy, 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, lightness, high surface area, adaptability to functionalization, barrier properties, optical transparency and energy absorption capabilities, as well as its suitability for injection molding and 3D printing applications, positions 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 in their pure form with plasticizers or small quantities of thermoplastic resin in the powder bed in MJF printing processes where exposure to light is done using a projector (as opposed to the selective laser beam in SLS printing).

[0053] Carbon black, more commonly known as soot, is also an advantageous bio-based filler. It can be obtained, for example, from numerous waste materials, such as coconut shells, notably through calcination, which allows for the valorization of waste, particularly from the agri-food industry. Due to its black color, this type of bio-based filler cannot, however, be used in MJF printing, but is very well suited to SLS printing. It exhibits excellent thermal stability and can be supplied with a very fine particle size, making it suitable for SLS printing.

[0054] According to another aspect of the invention, the particle size distribution 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

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

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

[0057] These particle sizes ensure, in particular, good homogeneity of the mixture. Indeed, when the size (and density) of the particles in the bio-based filler corresponds to that of the thermoplastic resin powder, the homogeneity and packing behavior of the powder bed are improved, resulting in better print quality. In the case of injection molding, where the molten material is mixed using a screw to obtain a certain homogeneity, a homogeneous particle size distribution in the bio-based filler is less critical.

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

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

[0060] According to one aspect of the invention, the thermoplastic matrix is ​​composed of one or more thermoplastic polymers of petrochemical or bio-based origin. Indeed, the use of a thermoplastic polymer is particularly well suited to additive manufacturing and injection molding. The use of bio-based thermoplastic polymers is advantageous in that it further reduces the overall environmental and ecological impact of the composite material.

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

[0062] Among thermoplastic polyamides (PA), PA 11 and / or PA 6-10, which can be bio-based, can be advantageously used.

[0063] Among thermoplastic polyesters, polyhydroxyalkanoates (PHA), polylactic acid (PLA), polybutylene succinate (PBS), polyethylene furanoate (PEF) can advantageously be used, which can be partially bio-based, as well as polycaprolactone (PCL), polybutylene adipate terephthalate (PBAT), which are biodegradable and can be partially bio-based.

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

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

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

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

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

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

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

[0071] Polyesters that can be bio-based, 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.

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

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

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

[0075] The higher the bio-based filler content in the mixture, the lower the carbon footprint of the thermoplastic composite material. However, a high bio-based filler content negatively impacts layer adhesion in 3D printing because it may then be necessary to significantly adapt the manufacturing process depending on the specific nature of the thermoplastic composite material. A high bio-based filler content is also likely to affect the material's mechanical properties, particularly its elastic properties. Indeed, the higher the bio-based filler content, the stiffer and harder the sintered material.

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

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

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

[0079] According to one aspect of the invention, at least one additive is selected from a list consisting of colorants, flame retardants, bonding agents, finishing agents, detailing agents, plasticizers, coupling agents, thermal stabilizers, thermal control agents, melt inhibitors, UV stabilizers, lubricants, nucleating agents, solvents, compatibility agents, 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 articles manufactured with the thermoplastic composite material of the invention and / or to improve the manufacturing processes using it.

[0080] According to one aspect of the invention, the thermoplastic composite material has the following formulation: 1. 10 to 40% by weight, preferably 15 to 25%, of bio-based filler, 2. 50 to 95% by weight, preferably 75% to 90%, of thermoplastic matrix, and 3. 5 to 15% by weight, preferably 8 to 12%, of at least one additive.

[0081] This formulation is advantageous in that it is particularly suitable for injection molding, especially when the thermoplastic composite material mainly comprises one or more plasticizers among the additives.

[0082] It should be noted that in this formulation, the bio-based filler can, for example, have any particle size, including greater than 100 pm.

[0083] According to another aspect of the invention, the thermoplastic composite material has the following formulation: 1. 5 to 20% by weight, preferably 10 to 15%, of bio-based filler, 2. 75 to 95% by weight, preferably 85 to 95%, of thermoplastic matrix, and 3. from 0 to 20% by weight, preferably from 0 to 10% by weight of at least one additive.

[0084] 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 includes thermoplastic polyurethanes, polyamides or polyesters.

[0085] It should be noted that in this formulation, the bio-based 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 about 50 µm.

[0086] According to one aspect of the invention, in this second formulation the thermoplastic polymer is preferably chosen from the following polymers and their mixture: polyamide 11 (PAU), polyamide 12 (PA12), polystyrene (PS), thermoplastic elastomers (TPE), polyetherimide (PEI), polyethersulfones (PESU) and polymers of the polyaryletherketone family (PAEK).

[0087] 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, fusion inhibitors, colorants, surface modifiers, stabilizers, solvents and compatibility enhancers.

[0088] According to another aspect of the invention, particularly in MJF printing, one of the aforementioned additives is a colorant incorporated in glycerin. Indeed, this additive has shown high efficiency in binding the powdered bio-based filler and the powdered thermoplastic matrix, whereas it is not generally used as a binding or detailing agent in 3D printing.

[0089] 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 allows an article to be manufactured at a lower cost and with a reduced environmental and ecological impact.

[0090] According to one aspect of the invention, the article is manufactured by additive manufacturing using a 3D powder bed printing technology.

[0091] 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.

[0092] Indeed, these technologies are advantageously suited to the use of a powdered material.

[0093] 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

[0094] The figures are presented for illustrative purposes only and are in no way limiting of the invention.

[0095] [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.

[0096] [Fig.2] is a histogram illustrating the evolution of the maximum stress for the tests of [Fig.1].

[0097] [Fig.3] is a histogram illustrating the evolution of the strain at maximum stress for the tests of [Fig.1].

[0098] [Fig.4] is a photograph of tensile test samples printed by SLS with 90% of Ultrasint® TPU 88A and 10% mycelium powder.

[0099] [Fig.5] is a photo of a part with complex geometry printed by SLS with 90% Ultrasint® TPU 88A and 10% mycelium powder.

[0100] [Fig.6] illustrates the particle size distribution of a first mycelium powder designated as Mycelium 1.

[0101] [Fig.7] illustrates the particle size distribution of a second powder of mycelium designated as Mycelium 2.

[0102] [Fig.8] illustrates the results of a thermal characterization test for a powder comprising 100% TPU alone.

[0103] [Fig.9] illustrates the results of a thermal characterization test for a powder comprising 90% Ultrasint® TPU 88A and 10% fine mycelium powder.

[0104] [Fig. 10] illustrates the results of a thermal characterization test for a powder comprising 90% of Ultrasint® TPU 88A and 10% of very fine mycelium powder.

[0105] [Fig. 11] illustrates the results of a thermal characterization test for a powder comprising 90% of Ultrasint® TPU 88A and 10% of olive kernel powder.

[0106] [Fig. 12] illustrates the dimensions of a test sample printed by SLS with powders according to the invention.

[0107] [Fig. 13] illustrates printing results of test samples printed by SLS at three different laser speeds with a powder comprising 90% Ultrasint® TPU 88A and 10% very fine mycelium powder.

[0108] [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].

[0109] [Fig. 15] is a profile view of the test specimen located on the left in [Fig. 14].

[0110] [Fig. 16] illustrates results of printing complex shape samples by SLS with two different powders according to the invention.

[0111] [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.

[0112] [Fig. 18] illustrates the main tensile properties of SLS-printed test samples in the Z direction with the S2 method printing parameters given in [Table 9], with two different powders according to the invention and two different TPU-only powders for comparison.

[0113] [Fig. 19] illustrates the main tensile properties of SLS-printed test samples with two different laser speeds using a powder according to the invention. DETAILED DESCRIPTION

[0114] Unless otherwise indicated, the % given in this text are percentages by weight.

[0115] 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-based filler.

[0116] This thermoplastic composite material is preferably intended to serve as a raw material for the manufacture of articles, and in particular sporting goods such as a shoe part (upper or sole for example), a textile garment, a bicycle part, a table tennis table element, a luggage reinforcement part, etc.

[0117] For this purpose, the thermoplastic composite material is in powder form, which makes it particularly suitable for use in additive manufacturing or injection molding. Indeed, such a composition has shown satisfactory results for manufacturing articles by 3D printing and injection molding.

[0118] According to one embodiment, the particle size distribution of the thermoplastic composite material is such that at least 50% of the grains (by number) have a diameter strictly less than 32 pm and such that at most 50% of the grains (by number) have a diameter between 32 and 63 pm.

[0119] Preferably, the particle size distribution 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 and 63 pm.

[0120] According to another embodiment, the particle size distribution 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.

[0121] It should be noted that D10 is always smaller than D50 which is smaller than D90, and the closer their values ​​are, the more homogeneous the grain size.

[0122] The thermoplastic composite material of the invention comprises 5 to 40% by weight, preferably 10 to 20% by weight, of bio-based filler. This bio-based filler is suitable for use in injection molding or additive manufacturing, in particular by MJF or SLS technology.

[0123] According to one embodiment, the mixture of a thermoplastic matrix and a bio-based filler comprises between 10% and 20% by weight of bio-based filler, particularly 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 injection molding, especially when the elastic properties of the material are to be prioritized.

[0124] According to another embodiment, this percentage by weight of bio-based filler can 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, such a composition has also shown satisfactory results for the manufacture of articles by 3D printing and injection molding, particularly when the rigidity of the material is a priority.

[0125] In order to valorize bio-based organic waste, the composite material according to the invention comprises a bio-based filler, which is therefore derived directly or indirectly from biomass. This bio-based filler can, for example, come from mushrooms, fruit shells, coffee grounds, etc. In general, it can come from any bio-based organic product that allows for the direct or indirect valorization of waste or an inexpensive material derived from renewable organic matter of plant, fungal, or animal origin.

[0126] In addition to the bio-based filler, the composite material according to the invention may include a non-bio-based filler.

[0127] Generally speaking, for economic, ecological and environmental reasons, it is advantageous to have the largest possible amount of charge bio-based in the composite material of the invention. However, an excessive amount of bio-based filler is likely to degrade the mechanical and aesthetic properties of articles manufactured from such a composite material.

[0128] According to a preferred embodiment of the invention, the bio-based 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. "Predominantly" means that 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 constitutes more than 50% by weight of the total bio-based filler.

[0129] In addition, the ground bio-based feed can be subjected to pretreatment processes to impregnate it with additives, chemically modify the surface of the particles or coat the sharp particles in a spherical thermoplastic matrix, thus facilitating the sintering process within the framework of the SLS / MJF technology.

[0130] The powdered mycelium used in the invention is preferably obtained from fungal culture, which is a biotechnological process in which, by decomposing a feeding substrate, a fungus creates an interconnected mycelial network. Advantageously, the substrate can be a waste product, generally organic, and of low value, for example, straw, plant matter, or sawdust. It can also be plastic waste, cigarette filters, or other waste that is usually difficult to recycle. The mycelial filaments are called hyphae, and are made up of elongated cells. The mycelial cell wall consists of chitin, glucans, proteins, and lipids, the concentration of which depends on the feeding substrate, which ultimately defines the properties of the mycelium.Thus, mycelium is a tenacious mixture of chitin-glucan matrices and filamentous intracellular cross-linking which, once rendered inert (also said to be inactivated) and reduced to powder, can constitute a bio-based filler usable within the framework of the invention.

[0131] After their growth, the mycelial strains are preferentially 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 bio-based filler of the composite material according to the invention.

[0132] Among the fungi used, examples include the ganodermataceae, in particular Ganoderma lucidum, the oyster mushrooms, in particular Pleurotus ostreatus, and the polyporaceae, in particular Trametes versicolor.

[0133] The powdered walnut shell used in the invention is preferably obtained from walnut shells from the agricultural production of edible walnuts, produced by walnut trees, trees of the Juglandaceae family, for example, of the genus Juglans regia. The walnut is an oily and highly energy-rich 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 valorize this waste product from the agri-food industry.

[0134] Similarly, the powdered olive pit used in the invention is preferably obtained from olive pits from olive farming, particularly for the purpose of producing oil or pitted olives. Here again, the use of the pits, reduced to powder, for example by grinding, thus makes it possible to valorize this waste product from the agri-food industry.

[0135] Cellulose nanofiber powder is primarily derived from plant-based materials. The most common sources are wood pulp and cotton. Cellulose nanofibers are extracted from these plant materials by mechanical or chemical processes. They are advantageous because of their strength, lightness, and biodegradability.

[0136] Starch is a carbohydrate found in many plants, particularly in their roots, tubers, and seeds. Common sources of starch powder include maize, potatoes, wheat, rice, and cassava. Starch powder is extracted by crushing these plant parts and processing them to separate the starch.

[0137] Alginate is extracted from brown algae, such as species of the Laminaria family. These algae are found in the oceans, particularly in cold regions. Alginate is extracted from the algae by a process involving the use of alkaline solutions.

[0138] 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.

[0139] Preferably, the thermoplastic matrix comprises a petrochemical-derived thermoplastic polymer, a bio-based thermoplastic polymer, or a mixture thereof. This polymer or polymer mixture is suitable for use in injection molding or additive manufacturing.

[0140] According to one embodiment of the invention, a thermoplastic polymer of the thermoplastic matrix can 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.

[0141] In addition to the thermoplastic matrix and the bio-based 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.

[0142] An additive is defined as 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.

[0143] One of these additives may for example be chosen from colorants, flame retardants, bonding agents, detailing agents, plasticizers, coupling agents, thermal stabilizers, UV stabilizers, lubricants, nucleating agents, compatibility agents and additives intended to improve laser absorption.

[0144] 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.

[0145] According to a first variant of the invention, the thermoplastic composite material has a formulation specifically adapted for injection molding.

[0146] For injection molding, the requirements differ from those for additive manufacturing and are less stringent. Indeed, a very wide range of combinations of thermoplastic matrix and bio-based filler are possible. The requirements stem primarily from the desired properties of the final material, such as Shore hardness, tensile strength, etc.

[0147] For injection molding, the composite material comprises 50 to 95% by weight, preferably 75 to 90%, of thermoplastic matrix.

[0148] According to a second embodiment of the invention, the thermoplastic composite material has a formulation specifically adapted for additive manufacturing, and in particular for additive manufacturing by 3D printing. "3D printing" refers to the direct deposition of a material from a printing device onto a substrate or a layer of material that has already been printed. In one or more aspects of the invention, 3D printing includes the extrusion of a material from a printing device onto a substrate or a layer of material that has been previously printed. In other aspects of the invention, 3D printing includes the ejection or jet (for example, by spraying) of droplets of a material from a printing device.In other aspects of the invention, 3D printing includes the deposition of a material in powder or granule form and the consolidation of said material by thermal activation using a selective laser beam or a projector light source. This can be combined with the application of a bonding agent to improve the sintering of the powdered or granulated material. The 3D printing according to the invention excludes the injection of material into a cavity of a mold temporarily placed next to a substrate surface, in which a shape, location, or thickness of the material injected onto the substrate is constrained by the mold according to conventional injection molding techniques.

[0149] Among the additive manufacturing processes suitable for using the thermoplastic composite material of the invention, one can notably mention powder bed additive manufacturing, for example based on the multi-jet fusion technology known in English as 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 binder jet printing technology known in English as Binder Jet Printing and under the acronym BJ3DP and the spray technology known in English as Spray.

[0150] SLS technology relies on laser energy to sinter the powder, while MJF technology uses a combination of bonding agents and a light projector. SLS materials often offer more limited color variation, resulting in parts that are generally white or gray unless dyed after printing. MJF parts have a more uniform black color due to the use of dark-colored bonding agents and can achieve smoother, more detailed surface finishes. BJ3DP technology is very similar to MJF, except that the detailing agent is absent.

[0151] Although all three techniques use thermoplastic base materials, the presence of the combination of two material jets, namely bonding agents and detailing agents, with light inducing sintering, makes MJF technology advantageously a very versatile method for modifying the final properties of the material, such as its flexibility, strength and texture.

[0152] For additive manufacturing, the thermoplastic matrix preferably represents 75 to 95% by weight, more preferably 85 to 95%, of the thermoplastic matrix of the thermoplastic composite material according to the invention.

[0153] The bio-based filler preferably represents 5 to 20% by weight, more preferably 10 to 15%, of the thermoplastic composite material according to the invention.

[0154] 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.

[0155] Selective laser sintering (SLS) is a 3D printing process based on selective laser sintering without a liquid phase, where layers of powder are sintered or fused layer by layer by means of laser energy.

[0156] SLS printing mainly uses fine thermoplastic powders. Thus, the particle size of the thermoplastic composite material for SLS printing preferentially varies from 20 to 100 micrometers, the uniform particle size ensuring uniform sintering and high-quality printing resolution.

[0157] For SLS printing, the constituent material of 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 (PAEK) family, for example such as polyetheretherketone (PEEK) or polyetherketoneketone (PEKK), or a mixture thereof.

[0158] Among these polymers, those with a melting point above 300 °C are preferred more preferentially.

[0159] For SLS printing, among the additives of the thermoplastic composite material according to the invention, one can notably include at least one additive formulated to improve laser absorption, in an amount of 0 to 10% by weight in the thermoplastic composite material.

[0160] For SLS printing, 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.

[0161] The table below gives examples of complete compositions of the composite material according to the invention intended for SLS printing.

[0162] [Tables 1] Composition Composition 1 Composition 2 Composition 3 Composition 4 Thermoplastic matrix Ultrasint® T Ultrasint® T Ultrasint® T Ultrasint® PA elastic PU 88A 90% PU 88A 90% PU 88A 90% 1190% Bio-source filler Mycelium in olive kernel NFC powder Mycelium in ée powder 10% in powder 10% 10% powder 10% Additives 0% 0% 0% 0%

[0163] MJF technology is a 3D printing process based on the fusion of powder layers where each layer is melted by infrared light in the appropriate places 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 delimit the contours of the object in order to guarantee high precision.

[0164] MJF printing also uses thermoplastic powders, the particle diameter being preferably between 60 and 100 pm.

[0165] For MJF printing, among the additives of the thermoplastic composite material according to the invention, one may include at least one bonding agent, also referred to as a fusion 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 refers to the bonding agent alone; it is a content of non-volatile substances that does not take into account the weight of the solvent in which the bonding agent may be present. Taking into account the solvent, which evaporates during MJF printing, the amounts of bonding agent solubilized in a solvent could, for example, be on the order of 50 to 100% by weight.

[0166] When the bonding agent is sprayed onto the powder bed, it helps define the shape of each layer and enables the fusion process through light absorption and the melting of individual particles. The bonding agent is generally a black liquid, which facilitates the absorption of heat from infrared light at the voxel to be printed.

[0167] However, in the context of using bio-based fillers, certain additives or components can be considered "binding agents" due to their role in facilitating the sintering process. Valuable and expensive components should be used in the binding agent rather than dispersed in the powder bed to enable economical production, even though the MJF process is considered to have high recyclability of excess powders.

[0168] A dye is generally added to the bonding agent to provide visual contrast during the printing process, thereby facilitating quality control and inspection.

[0169] In more complex and innovative systems, additives may also include the products listed below.

[0170] Prepolymers: These are often the main component of thermoplastic matrix powders. Prepolymers can have different molecular weights and chemical compositions adapted to obtain the desired melting and sintering properties.

[0171] Chain elongating agents and crosslinking agents: 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.

[0172] Catalysts: Catalysts are used to accelerate the reaction between prepolymers, chain extenders, and the powdered thermoplastic matrix. Their presence can influence the sintering rate and the final properties of the material.

[0173] 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.

[0174] Fluidizers and plasticizers: To improve the fluidity of the thermoplastic matrix powder, fluidizers may be added. These help to obtain a uniform layer of powder during the printing process.

[0175] Colours or pigments: For aesthetic purposes or to differentiate materials, colours or pigments may be added to thermoplastic matrix powders.

[0176] Compatibility agents: These are added to improve compatibility between the different polymer components and the bio-based filler, thus ensuring a uniform sintering process.

[0177] In the case of MJF printing, a finishing agent can also be applied around the perimeter of the printed part before exposure to projector light to prevent any further reaction in the powder bed and to ensure a high surface quality of the printed part. Solvents with a low or medium boiling point are therefore most often used. The use of glycerin can also be beneficial depending on the powder composition.

[0178] A detailing agent can be used to define fine details and smooth surfaces of the printed object. It is generally applied to the outer perimeter and edges of the printed parts to modify how heat is absorbed during the melting process. The detailing agent helps achieve high resolution and accuracy in the final print by controlling the spread of the melting agent, the heat absorbed, and the subsequent melting and sintering of the powder. Essentially, it enhances the fine features and accuracy of the printed parts.

[0179] The detailing agent is a liquid thermal control agent. It is designed to modify the heat absorption characteristics of the powder bed. By controlling how light is absorbed and partially limiting how heat is distributed, this agent can improve the accuracy of the sintering process. This allows for better resolution of surface details, usually by combining them with solvents.

[0180] The detailing agent generally consists of low boiling point solvents which absorb the heat of the process by evaporation and act as fusion inhibitors, preventing the powder from melting in areas where the part should not form, resulting in better definition and sharper edges.

[0181] Other preferred additives include surface modifiers, thermal and UV stabilizers, solvents and compatibility enhancers.

[0182] A surface modifier allows the characteristics of the printed surface, such as gloss or texture, to be modified in order to obtain the desired aesthetic or functional properties.

[0183] A thermal stabilizer helps ensure that the detailing agent remains effective throughout the printing process, particularly at high temperatures and under other challenging conditions.

[0184] A solvent is often combined with a detailing agent, which allows them to remain in a liquid state for precise application. They evaporate during the printing process.

[0185] A compatibility enhancer ensures that the detailing agent works harmoniously with the thermoplastic composite material powder and the bonding agent, without causing undesirable reactions.

[0186] A plasticizer may be present in an amount representing 10 to 20% by weight of the thermoplastic composite material because some composite materials may already include such an additive.

[0187] The thermoplastic composite material may contain from 0 to 20% plasticizer and from 0 to 10% other types of additives. Indeed, some thermoplastic materials used for the thermoplastic matrix may already contain such additives.

[0188] Other additives may, for example, be present in quantities representing 0 to 10% by weight of the thermoplastic composite material.

[0189] Formulations for MJF printing can be designed to optimize the interaction between a detailing agent, a bonding agent and a thermoplastic composite material powder, in order to ensure that the final printed parts have the desired mechanical properties, accuracy and surface finish.

[0190] The combination of a detailing agent and a bonding agent in MJF printing allows the creation of parts with complex geometries and excellent mechanical properties.

[0191] It should be noted that for MJF printing, the thermoplastic composite material according to the invention used must be compatible with the bonding agent.

[0192] The thermoplastic composite powder material according to the invention must also have a specific color, generally white, to prevent absorption of the heat produced by the melting lamp. If the color of the thermoplastic composite powder is too dark, a detailing agent containing white pigments can be used to prevent the melting of particles outside the printed perimeters.

[0193] For MJF printing, the thermoplastic composite material according to the invention must also have thermal properties allowing for 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.

[0194] 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 (PAU) or polyamide 12 (PA12), thermoplastic polyurethanes (TPU), other modified thermoplastics or a mixture thereof.

[0195] 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.

[0196] The table below gives examples of complete compositions of the composite material according to the invention intended for MJF printing.

[0197] [Tables2] Composition Composition 1 Composition 2 Composition 3 Composition 4 Thermoplastic matrix Ultrasint® T Ultrasint® T Ultrasint® T Ultrasint® PA elastic PU 88A 90% PU 88A 90% PU 88A 90% 1190% Bio-source filler Mycelium in olive kernel NFC powder Mycelium in ée powder 10% in powder 10% 10% powder 10% Additives 0% 0% 0% 0%

[0198] It is noted that these compositions are the same as for SLS printing.

[0199] 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 an optional additive. In this particular application of the invention, the bio-based filler behaves both as a filler and as a thermoplastic matrix.

[0200] The table below gives an example of the composition of the composite material according to the invention intended for MJF printing in which powdered mycelium serves both as a bio-based filler and as a thermoplastic matrix.

[0201] [Tables3] Composition 5 Powdered mycelium 70-90% Plasticizer 5-15% Liaison Officer 5-15%

[0202] These compositions gave excellent results when the binding agent is epichlorohydrin, glutaraldehyde, glyoxal or aqueous citric acid with a black pigment.

[0203] 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 with different thicknesses in different areas. Emulsions, suspensions, or solutions of the main material are generally used for spraying. 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 curing or setting processes, depending on the product chosen. 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 because it allows the manufacture of flexible and / or stretchable articles, including inflatable articles.

[0204] The invention also relates to a method of manufacturing an article from a thermoplastic composite material as described above.

[0205] According to a first variant of the invention, this manufacturing process includes an injection molding step from a thermoplastic composite material having a formulation specifically adapted for injection molding.

[0206] According to a second embodiment of the invention, this manufacturing process includes an additive manufacturing step using a thermoplastic composite material with a formulation specifically adapted for additive manufacturing. This additive manufacturing step is, for example, carried out by implementing a 3D printing technology, preferably a powder bed 3D printing technology, more preferably implemented by SLS or MJF.

[0207] For SLS / MJF printing, the two powders are mixed before filling the powder bed. The particle size distribution and the density of the bio-based filler are crucial for obtaining a homogeneous powder bed and a good printing result.

[0208] Tests

[0209] Tests were carried out with different formulations of thermoplastic composite material according to the invention. These tests are intended, in particular, to prove that these formulations make it possible to manufacture articles with satisfactory mechanical and aesthetic properties. While injection molding technology does not present any particular technical complexity, the tests are also intended to prove that the different formulations of thermoplastic composite material according to the invention are further suitable for use in additive manufacturing by a powder bed 3D 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.

[0210] Tensile strength tests (PAM technology)

[0211] A first series of tests aimed at validating tensile strength properties was carried out according to DIN 53504 with tensile samples (sometimes referred to as test specimens) 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 situated midway between 3D printing and injection molding, and which therefore allows for rapid and cost-effective validation of the feasibility of these two technologies. Indeed, PAM technology uses a nozzle, as in 3D printing, and a screw conveyor where the main material is melted, as in injection molding. Direct extrusion of granules (FGF), also known as fused granular fabrication, could also have been used.

[0212] [Tables4] Sample Family Formulation Manufacturing Process A 60% TPE + 40% PAM Mycelium B 100% TPU alone MJF C 100% TPU alone SLS D 90% TPU Ultrasint 88A + 10% MYC1 SLS Mycelium E 90% TPU Ultrasint 88A + 10% MYC2 SLS Mycelium F 90% TPU Ultrasint 88A + 10% OK SLS Olive Kernel

[0213] In sample A, the TPE is a proprietary matrix of the KUORI company, while the mycelium comes from two external deposits.

[0214] In samples D and E, MYC1 indicates a first so-called "fine" mycelium powder, the particle size distribution of which is given on [Fig.6], while MYC2 indicates a second so-called "very fine" mycelium powder, the particle size distribution of which is given on [Fig.7].

[0215] The table below gives the particle size of the bio-based fillers used in combination with TPU Ultrasint 88A for SLS printing.

[0216] [Tables5] Bio-based feedstock Average particle size D50 [pm] Maximum particle size [pm] MYC1 70 560 MYC2 32 63 OK 80 125

[0217] Ultrasint® TPU 88A refers to 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.

[0218] [Tableauxô] Ultrasint® TPU 88A Appearance Natural white powder Density (apparent density) [g / cm³] 0.5 Density (printed part) [g / cm³] 1.1 Average particle size d50 [µm] 70-90 Glass transition temperature [°C] -48 Melting temperature [°C] 120-150 Shore A hardness 88-90 Tensile modulus [MPa] X / Y direction 75 / 75 Ultimate tensile strength [MPa] X / Y direction 8 / 7 Elongation at break [%] X / Y direction 270 / 130

[0219] The tensile samples are all in the form of standardized flat test specimens (see [Fig. 4] and [Fig. 12]). For the tests, three to four samples from each family were tested.

[0220] The SLS-printed tensile samples were printed in a horizontal X / Y orientation.

[0221] 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.

[0222] 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 Newtons was induced.

[0223] The results of these tests are illustrated on [Fig.1] for the tensile sample A.

[0224] Maximum stress strain tests

[0225] A second series of tests aimed at validating the maximum stress and the deformation at maximum stress was carried out on normalized tensile samples A, B and C.

[0226] 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. On these In histograms, the column represents the mean of the four samples and the error bars are related to the standard deviation of the batch.

[0227] [Tables?] Sample Tensile Strength X / Y (MPa) Tensile Strength Z (MPa) Elongation at Break X / Y (%) Elongation at Break Z (%) A 2 + 10% - 11 + 7% - B 11 + 22% 7 + 18% 104 + 43% 55 + 40% C 8 + 5% 4 + 5% 74 + 9% 16 + 15% D 7 + 26% - 85 + 37% - E 7 + 10% 2 + 31% 71 + 8% 7 + 20% F 7 + 4% 1 + 27% 59 + 12% 10 + 27%

[0228] Based on these results, it can be deduced that SLS-printed composites exhibit material properties competitive with respect to pure reference materials with regard to tensile strength and elongation at break, while replacing 10% of fossil-based TPU with bio-based fillers.

[0229] The advantage of MJF printing over SLS printing is also highlighted, resulting in better layer adhesion and generally superior properties in the Z direction for MJF.

[0230] In particular for thermoplastic composite materials, material disadvantages related to layer orientation can be eliminated thanks to the advanced fusion properties of MJF printing.

[0231] For the same composition, injection molding gives a superior result compared to additive manufacturing because 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 exhibits isotropic properties, whereas additive manufacturing exhibits anisotropic properties depending on the printing orientation.

[0232] It should also be noted that no significant difference between samples of the same family was identified; it can therefore be inferred that the behavior is reproducible given the technology used to print the samples.

[0233] As can be seen in the photographs (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 with 10% mycelium and 90% TPU, and illustrated in [Fig. 5], exhibits significantly the same mechanical properties as the same item obtained by SLS printing made with 100% TPU.

[0234] Other tests described below were carried out with SLS technology by the company KUORI.

[0235] One of the objectives of these tests is to find appropriate printing parameters for the different powders and to understand how olive kernels compare to mycelium in terms of mechanical properties after SLS printing.

[0236] The results should make it possible to define the outlines of a possible transfer or reproduction with MJF technology and to further explore the possibilities of transfer and reproduction with MJF technology.

[0237] Thermal characterization tests

[0238] The powders of the samples from families C, D, E and F were characterized by Differential Scanning Calorimetry (DSC) on a TA Instruments DSC 25 in order to better understand the required printing parameters and the appropriate processing window.

[0239] The following thermal profile was used for the measurements:

[0240] - 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.

[0241] - Step 2: Gradual cooling at 10 °C / min from 200 °C to 0 °C in a nitrogen atmosphere.

[0242] - Step 3: Incremental heating at 10 °C / min from 0 °C to 200 °C in a nitrogen atmosphere.

[0243] The results of these tests are given on [Fig.8] to [Fig. 11], respectively for families C, D, E and F, where the first heating cycle is shown in thin line and where the cooling cycle is shown in thick line.

[0244] These DSC thermograms reveal that adding 10% by weight of bio-based filler does not affect the melting or crystallization range of the powder. The four powders analyzed each exhibit a melting range of approximately 130 to 150°C, with a peak at 142°C. The enthalpies of fusion are also unchanged. The peak crystallization temperature remains constant at 108°C. These experimental data are consistent with the specifications outlined in BASF's technical 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.

[0245] Production of samples by SLS printing

[0246] The samples were printed using a Sintratec SI SLS printer (laser = 2.3W, X = 445 nm), with a maximum printed object volume of 3.04 dm³ (130 mm x 130 mm x 180 mm). All samples were treated by sandblasting (Micropeen 950 ZPD, Lepco, Switzerland) to remove unsintered powder.

[0247] Powders from samples of families C, D, E, and F were used to fill the chambers of the SLS printer and produce test samples. Five test samples, each 3.8 mm thick, were printed in each printing session. Their dimensions are shown in [Fig. 12].

[0248] The appearance of these powders is given in the table below:

[0249] [Tables8] Sample Family Formulation Color Visual Control C 100% TPU alone Homogeneous white D 90% TPU Ultrasint 88A + 10% Mycelium MYC1 Gray Mycelium particles are clearly distinguishable E 90% TPU Ultrasint 88A + 10% Mycelium MYC2 Homogeneous gray F 90% TPU Ultrasint 88A + 10% Olive Kernel OK Homogeneous off-white / brown

[0250] In preliminary experiments, pure Ultrasint 88A TPU powder was used for printing. However, no interaction was observed between the laser beam and the powder, hence the absence of sintering. On the contrary, with increasing temperature, a molten block formed. This phenomenon is probably attributable to the white color of the powder, which results in insufficient absorption at the laser wavelength, combined with the relatively low power of the Sintratec SI laser (2.3 W).

[0251] In contrast, the addition of grey / brown bio-based fillers resulted in successful printing. Different printing parameters were tested. They are presented in the table below:

[0252] [Tables9] Method Heating temperature [°C] Printing temperature [°C] Laser speed [mm / s] Powdered surface Chamber Powdered surface Chamber SI 100.6 60.3 125.7 60.7 650.0 S2 100.6 60.3 120.7 60.7 450.0 S3 100.6 60.3 120.7 60.7 250.0

[0253] Effect of printing temperature: At a printing temperature of 125.7 °C (SI method), the test samples produced were enclosed in a compact block of powder, making powder recycling difficult. Even when lowering the printing temperature to 120.7 °C (S2 and S3 methods), which corresponds to the lower end of the melting range, the unused powder failed to flow freely. Therefore, all experiments were conducted using 100% fresh, unrecycled powder.

[0254] 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 was improved at the lower speeds. The individual particles are indeed less visible. Considering the relatively good quality obtained 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 using the S2 method.

[0255] Effect of powder composition: The three powder grades from samples in families D, E, and F were used to produce test samples with the S2 method for mechanical testing. The resulting test samples are shown in [Fig. 14] and [Fig. 15]. From left to right in [Fig. 14]: SLS_MYC2 (family E), SLS_MYC1 (family D), SLS-OK (family F). [Fig. 15] is a side view of an SLS_MYC2 test sample, printed with the S2 method. Visually, the SLS_MYC1 powder appears grayer and less homogeneous than the SLS_MYC2 and SLS_OK powders, probably due to the wider particle size distribution of the MYC1 powder.

[0256] Printing of complex hollow shapes

[0257] Compared to the more traditional 3D printing technique of fused deposition modeling (FDM), SLS printing makes it easy to fabricate hollow surfaces for which a support structure is generally required. The unfused powder serves as temporary support and can be recycled in a subsequent print. This is why More complex shapes were printed subsequently (see [Fig. 16]), using SLS_MYC2 (family E) and SLS_OK (family F) powders due to their superior performance. Initial tests with the S2 method proved difficult due to the presence of compacted powder trapped within the geometry, which was therefore difficult to remove without damaging the sample. To overcome this problem, the printing temperature was reduced by 5°C and the laser speed by 100 mm / s. The geometry was also scaled up. The geometry was enlarged by a factor of 1.4 to enlarge the holes in the geometry and allow for easier removal of the powder trapped within the sphere. The printing parameters used for SLS printing of complex hollow shapes are summarized in the table below.

[0258] [TableauxlO] Method Heating temperature [°C] Printing temperature [°C] Laser speed [mm / s] Powdered surface Chamber Powdered surface Chamber S4 100.6 60.3 115.7 60.7 350.0

[0259] Mechanical properties

[0260] The mechanical properties of the test samples were tested by tensile measurements over three repetitions. The maximum resistance (omax), the tensile strength (ob), the elongation at break (eb), as well as an approximation of the Young's modulus (E) were extracted from the stress-strain curves.

[0261] As shown in the table below and [Fig. 17], the tensile properties are within a similar range for all formulations. Due to the wide variability of the results, no conclusion can be drawn regarding the best-performing powder in terms of mechanical properties. Compared to BASF's TPU Ultrasint 88A, the samples produced exhibit lower elongation at break, but similar tensile strength and a higher modulus. Similar results were observed for KUORI's materials when bio-based fillers were added within 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 were defects in layer adhesion 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 the MJF... It 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.

[0262] [Tables 11] omax (X / Y) [M Pa] St. From v. [MP a] 0b (X / Y) [M Pa] St. From v. [MP a] E (X / Y) [MPa] St. Louis. From v. [MP a] Eb (X / Y) [%] St. From v. [%] SLS _MYC1 6.69 1.69 + 25.3% 6.32 1.37 + 21.7% 104.8 40.8 + 38.9% 84.9 31.5 + 37.1% SLS _MYC2 6.68% +61 0.61 10.3% 131.5 28.1 + 21.4% 71.3 5.9 +8.3% SLS _OK 7.01 0.29 + 4.1% 6.88 0.48 + 7.0% 135.5 37.8 + 27.2% Tur F 9.2.36 2 SLS 8 0,4 + 5 % - - - - 74 7+9% TPUFo umiss eur 1 MJF 11 2 + 22 % - - - - 104 45 +43%

[0263] Figure 17 shows the main tensile properties of three SLS powders printed using the S2 method in the horizontal X / Y plane. Young's modulus (or modulus of elasticity) is represented by light hatching, while tensile strength is represented by dense hatching. The tests were carried out on three samples. Two reference powders are given as examples. Tensile strength and modulus of elasticity correspond to the left axis, and elongation at break corresponds to the right axis.

[0264] 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 widest distribution. For subsequent use of MYC1 as a bio-based filler, sieving and / or grinding is recommended.

[0265] Effect of printing direction: The effect of the printing direction on mechanical properties was evaluated by printing the test samples in the Y / Z plane. Mechanical properties were significantly reduced compared to samples printed in the horizontal X / Y plane, both for the samples printed by KUORI and for the reference samples. Analysis in the Y / Z plane provides important insight into layer adhesion during the printing process. SLS printing generally results in less efficient particle sintering from one layer to the next compared to the MJF process. Even weaker layer cohesion was observed for the thermoplastic composite material samples printed by SLS. It should be noted that the performance of the MJF reference is exceptional compared to that of the SLS reference.

[0266] The table above summarizes the tensile properties tested in the vertical Z direction. The values ​​are based on three repetitions. For comparison, two reference TPU powders for SLS and MJF printing are given (supplied by the depositor).

[0267] [Tables 12] Πmax (X / Y) [M Pa] St. From v. [MP a] (X / Y) [M Pa] St. De v. [MP a] E (X / Y) [MPa] St. De v. [MP a] Eb (X / Y) [%] St. De v. [%] SLS _MYC1 - - - - - - - - SLS _MYC2 1.51 0.47 + 31.0% 1.51 0.47 + 31.0% - - 7.4 1.5 +2 0.3% SLS _OK 1.26 0.34 + 26.8% 1.26 0.34 + 26.8% - - 10.0 6.5 +2 6.8% TPU Supplier 2 SLS 4 0.2 + 5% - - 16 2+15% TPU Supplier 1 MJF 7 1 + 18% - - - - 55 22 +40%

[0268] Figure 18 shows the main tensile properties of SLS_MYC2 and SLS_OK printed in the Z direction. Tensile strength is represented by dense hatching. The tests were carried out on four copies. Two Reference powders are given as examples. Tensile strength corresponds to the left axis, elongation at break to the right axis.

[0269] Effect of laser speed: [Fig. 19] highlights the absence of any effect of changing the laser speed on the tensile properties. The samples tested included SLS_MYC2 printed at a laser speed of 450 mm / s (S2) and 250 mm / s (S3). The 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. However, a significant change in sintering behavior, and therefore in mechanical properties, is expected when changing the laser power.

[0270] 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 technical data sheet for BASF's Ultrasint powder (approximately 85 versus 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.

[0271] The table above summarizes Shore A and D hardnesses as a function of powder composition and laser speed.

[0272] [Tables 13] Laser speed Powder Shore A Shore D 450 mm / s SLS_MYC1 85 29 SLS_MYC2 85 31 SLS_OK 84 28 650 mm / s SLS_MYC1 81 28 250 mm / s SLS_MYC2 85 30

[0273] Conclusions and perspectives

[0274] These tests successfully demonstrate that it is possible to use mycelium-based thermoplastic composite materials according to the invention for SLS printing, representing a significant advance in the field of biocomposite printing. The inability of TPU Ultrasint 88A, a pure white powder from BASF, to sinter due to inadequate interaction with the SLS printer's laser beam was effectively resolved by incorporating 10% by weight of Bio-based fillers such as mycelium powder or olive kernel powder were used. This strategy generated sufficient heat for particle sintering and improved the powder's durability quotient through increased bio-based content.

[0275] Although the addition of bio-based fillers resulted in a notable reduction in the elongation at break of the printed samples compared to the datasheet, the mechanical properties obtained were comparable to the data provided by the depositor for SLS printing, thus confirming the viability of this approach. The MJF printing process, with its superior sintering capabilities, particularly with regard to layer orientation, offers a potential way to overcome the observed limitations in tensile strength and elongation at break in the Z direction.

[0276] The introduction of 10% by weight of bio-based fillers did not significantly alter the color of the powder, which suggests compatibility with the MJF printing process, which generally requires a white powder.

[0277] The differences in material properties observed between the two types of mycelium powders, MYC1 and MYC2, and the OK olive kernel composite samples highlight the impact of particle size and homogeneity of powder mixtures on the quality of the final product, as we have seen in previous test results reports.

[0278] 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 low percentage (5 to 40%) of thermoplastic resin, these base materials can create a powder bed suitable for MJF printing.

[0279] Although described through a number of examples, variants and embodiments, the thermoplastic composite material according to the invention and the process of manufacturing an article from it include various variants, modifications and improvements which will be obvious to a person skilled in the art, it being understood that these variants, modifications and improvements form part of the scope of the invention.

Claims

Demands

1. 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 bio-based materials in powder form and the thermoplastic composite material being in powder form, the particle size distribution of these powders being such that 50% or more of the grains by number have a diameter strictly less than 32 pm and in that 50% or less of the grains by number have a diameter between 32 and 63 pm.

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

3. Thermoplastic composite material according to claim 1 or 2, characterized in that its particle size is such that 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 bio-based origin.

5. Thermoplastic composite material according to the preceding claim, characterized in that the thermoplastic polymer is selected from the following polymers and mixtures thereof: 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-based 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 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-based 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 selected from the list consisting of colorants, flame retardants, bonding agents, finishing agents, detailing agents, plasticizers, coupling agents, thermal stabilizers, thermal control agents, melt inhibitors, UV stabilizers, lubricants, nucleating agents, solvents, compatibility agents, 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: - 10 to 40% by weight, preferably 15 to 25%, of bio-based filler, and - 50 to 95% by weight, preferably 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: - 5 to 20% by weight, preferably 10 to 15%, of bio-based filler, and - 75 to 95% by weight, preferably 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 selected from the following polymers and mixtures thereof: polyamide 11 (PAU), polyamide 12 (PA12), polystyrene (PS), elastomers thermoplastics (TPE), polyetherimide (PEI), polyethersulfones (PESU) and polymers of the polyaryletherketone family (PAEK).

13. A method for 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. A method according to the preceding claim, characterized in that the article is manufactured by additive manufacturing according to a 3D powder bed printing technology.

15. A 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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