Regolith-based formulations

Abstract

The invention relates to particular formulations combining a biodegradable matrix and a regolith filler usable in 3D printing, in particular for the manufacture of objects during extraterrestrial missions, for example on the moon or on Mars.

Description

Title of the invention: Regolith-based formulations technical field

[0001] The invention relates to specific formulations combining a biodegradable matrix and a regolith filler usable in 3D printing, particularly for the manufacture of objects during extraterrestrial missions, for example to the Moon or Mars. Technological background

[0002] Extraterrestrial soils are of increasing interest and are driving the rapid development of space technologies, including those related to three-dimensional (3D) printing. Being able to manufacture new equipment and repair damaged equipment on these planetary bodies is essential due to the physical and temporal constraints associated with space exploration. NASA (National Aeronautics and Space Administration) launched a 3D printer to the International Space Station (ISS) to explore 3D printing in a space environment. Meanwhile, the European Space Agency (ESA) conducted a feasibility study to determine whether an outpost made from lunar soil could be 3D printed on the Moon.

[0003] While ESA has successfully demonstrated that large-format 3D printing can create stable structures from lunar regolith in an atmosphereless environment, their technique is limited to the fabrication of large-scale buildings. The 3D printing of objects usable in agriculture remains unexplored, particularly the fabrication of biodegradable objects from regolith that may have water-soluble and / or fertilizing properties.

[0004] The applicant has developed particular formulations combining a biodegradable matrix and a regolith filler usable in 3D printing, in particular 3D printing by fused deposition modeling or by stereolithography.

[0005] Fused deposition modeling (FDM) or fused filament fabrication (FFF) is a 3D printing process that has become the most widespread, particularly among individuals. Generally, three steps are required to prepare a 3D object from raw materials using the fused deposition modeling technique, namely: - The preparation of a composition comprising a mixture of raw materials of 2 types: (i) a matrix which is generally of the "plastic" type chosen according to the desired characteristics and (ii) a filler which gives properties to the composition; - The spinning (or extrusion) of the composition comprising the matrix and the filler to manufacture a filament usable by a 3D printer, and - 3D printing proper by melting a filament via a nozzle (extruder or extrusion head) and depositing the molten material in successive layers onto a support to manufacture a 3D object.

[0006] Fig. 1 schematically illustrates the manufacture of a filament-type consumable usable by a 3D printer.

[0007] However, the regolith-based compositions currently used in 3D printing techniques are not suitable for use in agriculture. In particular, these compositions are generally not biodegradable, not water-soluble, and they do not contain a fertilizer, especially one with thermal properties and a particle size suitable for use in 3D printing.

[0008] There is therefore a real need to develop regolith-based compositions whose constituents are suitable for use in agriculture and which can be used for 3D printing, for example 3D printing by fused deposition modeling or 3D printing by stereolithography. Summary of the invention

[0009] Thus, the present invention, which finds application in the field of space agriculture, aims to provide compositions, comprising regolith, usable for the manufacture of fertilizing materials, such as fertilizing particles, by 3D printing.

[0010] According to a first aspect, the invention relates to a composition for three-dimensional (3D) printing comprising: - a biodegradable matrix, and - a charge of regolith.

[0011] According to a second aspect, the invention relates to a 3D printer consumable having a composition according to the invention, such as a consumable in solid form, for example a filament, a cylinder, a granule or a film.

[0012] According to a third aspect, the invention relates to the use of a composition according to the invention, or of a consumable according to the invention, for the preparation of a 3D printed object.

[0013] According to a fourth aspect, the invention relates to a method for preparing a 3D printed object comprising the steps of: a) obtain a composition according to the invention or a consumable according to the invention; b) heat the composition or consumable from step a) in a 3D printing nozzle to obtain a molten composition or consumable; c) apply layer by layer the composition or molten consumable obtained in step b) onto a support using the 3D printing nozzle to form a 3D printed object. Detailed description of the invention

[0014] Definitions

[0015] In the context of the present invention, the term "three-dimensional printing" or "3D printing" refers to a process for manufacturing three-dimensional parts by adding or agglomerating material. 3D printing makes it possible to create a real object: a designer designs the 3D object using a computer-aided design (CAD) tool. Generally, the resulting 3D file is processed by specific software that organizes the slicing of the different layers necessary to create the part. The sliced ​​file is sent to the printer, which deposits or solidifies the material layer by layer until the final part is obtained. It is the stacking of the layers that creates the volume. The 3D printing according to the present invention consists of melting a consumable through a heated nozzle and depositing molten material layer by layer (also known as FDM or FFF 3D printing).

[0016] In the context of the present invention, the term "matrix" refers to the component that provides support and / or structure to a 3D printing composition. The matrix is ​​generally the component that enables the formation and maintenance of the three-dimensional solid structure of a 3D-printed part. Matrices used in 3D printing are generally of the "plastic" type. In the context of the invention, the matrix must be biodegradable, including when in solid form. The matrix may also be water-soluble, including when in solid form.

[0017] The term “biodegradable,” as used in the context of the present invention, refers to the property of a substance to degrade under the action of microorganisms such as bacteria, fungi, or algae, producing elements that have no harmful effect on the natural environment. Thus, a “biodegradable matrix” according to the invention has the property of degrading under the action of microorganisms present in the soil, including when it is in solid form. Several microorganisms present in the soil are responsible for degradation, for example, bacteria, such as phosphorus-solubilizing bacteria and / or PGPR (Plant Growth Promoting Rhizobacteria) type bacteria, such as Bacillus amyloliquefaciens; and endosymbiotic fungi, such as Piriformospora indica.Advantageously, the biodegradable matrix according to the invention is capable of degrading by at least 50% by mass, for example at least 70%, at least 80%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least . 95%, at least 96%, at least 97%, at least 98%, at least 99%, for example of approximately 100%.

[0018] The term "water-soluble," as used in the context of the present invention, refers to the property of a substance to dissolve in water. Thus, a "water-soluble matrix" according to the invention has the property of dissolving in water, including when it is in solid form. The matrix according to the invention can be water-soluble by at least 20% by mass in excess water, for example, by at least 30%, 40%, 50%, 60%, 70%, 80%, or 90%, such as at least 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99%, for example, by about 100%. For example, the water solubility of PVA (Mowiflex) is about 100% in excess water, the water solubility of sodium caseinate (Lactips) is about 80% in excess water and the water solubility of TPS (Potato Starch Polymer) is about 40% in excess water ([Fig.2]).

[0019] The term "biodegradable water-soluble matrix" as used in the context of the present invention refers to a matrix that is both water-soluble and biodegradable.

[0020] In the context of the present invention, the term "fertilizing charge" refers to any product whose physicochemical characteristics allow it (i) to be used in a composition for 3D printing and (ii) to ensure or improve the physical, chemical, or biological properties of soils as well as plant nutrition. Such a charge may be, for example, a fertilizer and / or a soil amendment. Fertilizers are defined as fertilizing materials whose main function is to provide plants with nutrients (major nutrients, secondary nutrients, and trace elements). For example, the fertilizing charge may be selected from phosphate (P), calcium carbonate (CAC), struvite (VIT), calcium sulfate (ANH), diatomaceous earth (TD), or a mixture thereof. Phosphate may, for example, be selected from natural phosphate, sedimentary phosphate, or igneous phosphate..

[0021] In the context of the present invention, the term "regolith filler" refers to regolith whose physico-chemical characteristics allow it to be used in a composition for 3D printing.

[0022] In the context of this invention, the term "regolith" commonly refers to the layer of dust present on the surface of planets without atmospheres or natural satellites such as the Moon. Regolith is generally produced by meteorite impacts and by the solar wind at the surface. Examples include "lunar regolith" and "Martian regolith." Regolith can also be obtained on Earth synthetically. The term "regolith" encompasses both natural and synthetic regolith.

[0023] In the context of the present invention, the term "filament" or "3D printing filament" refers to a wire of variable diameter and length manufactured (generally by extrusion) from a composition comprising a matrix and a filler. The filament can be used as a consumable for FFF-type 3D printing. The filament is generally wound onto a spool. When used by an FFF-type 3D printer, the filament is heated in a 3D printing nozzle to obtain a molten filament, which is then applied layer by layer onto a substrate.

[0024] In the context of the present invention, the term "granule" or "3D printing granule" refers to an element of variable size made from a composition comprising a matrix and a filler. The granule can be used as a consumable for FFF-type 3D printing. Unlike filament, the granule cannot be wound due to its shape. When used by an FFF-type 3D printer, the granule is heated in a 3D printing nozzle to obtain a molten granule, which is then applied layer by layer onto a substrate.

[0025] In the context of the present invention, the term "melting temperature" or "melting point" is the temperature at which an element or compound changes from a solid to a liquid state.

[0026] Composition for 3D printing

[0027] According to a first aspect, the invention relates to a composition for three-dimensional (3D) printing comprising: - a biodegradable matrix, and - a regolith filler.

[0028] The composition according to the invention may be in solid or liquid form. Liquid compositions may have different viscosities, which give them distinct flow properties. Generally, the composition is in solid form at room temperature (approximately 25°C) and in liquid form when heated above its melting point. The melting point must be adapted for 3D printing; for example, the composition is in liquid form when heated in a 3D printing nozzle. The melting point of the composition according to the invention may be above 40°C, for example, above 100°C, for example, between 100°C and 300°C.

[0029] The melting temperature of the composition according to the invention generally depends on the melting temperatures of each of the constituents of the composition, in particular the melting temperature of the matrix. Advantageously, the biodegradable matrix has a melting temperature above 40°C, for example above 100°C, for example between 100°C and 300°C. Advantageously, the filler fertilizer has a melting point above 80°C, for example above 100°C, for example between 100 and 300°C.

[0030] In a particular embodiment, the biodegradable matrix is ​​chosen from: (i) polyhydroxyalkanoate (PHA), (ii) poly-[3-hydroxybutyrate (PHB), such as poly(3-hydroxybutyrate-co-3-hydroxyhexanoate (PHBH) or polyhydroxybutyrate-valerate (PHBV), (iii) poly vinyl alcohol (PVA), (iv) polylactide (PLA), (v) poly(butylene adipate-co-terephthalate (PBAT), (vi) a natural, plasticizer-free copolymer plasticized with glycerol, (vii) Glycerol-extruded sodium caseinate (LACTIPS), (viii) Polybutylene adipate terephthalate (PBAT), (ix) a mixture of several biodegradable matrices selected from (i) to (viii).

[0031] In one embodiment, the biodegradable matrix is ​​selected from poly vinyl alcohol (PVA), polybutylene adipate-co-terephthalate (PBAT), glycerol-extruded sodium caseinate (LACTIPS) or a mixture of two or more of these.

[0032] The biodegradable matrix may be water-soluble. In one embodiment, the biodegradable matrix is ​​(i) a water-soluble biodegradable matrix, (ii) a non-water-soluble biodegradable matrix, or (iii) a mixture of a water-soluble biodegradable matrix and a non-water-soluble biodegradable matrix.

[0033] Examples of water-soluble matrices are poly vinyl alcohol (PVA), polylactide (PLA), a natural plasticizer-free copolymer plasticized with glycerol, glycerol-extruded sodium caseinate (LACTIPS).

[0034] An example of non-water-soluble matrices is polybutylene adipate terephthalate (PBAT), polyhydroxyalkanoate (PHA) and poly-[3-hydroxybutyrate (PHB), such as poly(3-hydroxybutyrate-co-3-hydroxyhexanoate (PHBH) or polyhydroxybutyrate-valerate (PHBV).

[0035] In one embodiment, the biodegradable matrix is ​​a mixture of a water-soluble biodegradable matrix and a non-water-soluble biodegradable matrix, for example a mixture of poly vinyl alcohol (PVA) and polybutylene adipate terephthalate (PBAT), or a mixture of glycerol-extruded sodium caseinate (LACTIPS) and polybutylene adipate terephthalate (PBAT).

[0036] The mixture of a water-soluble biodegradable matrix and a water-insoluble biodegradable matrix is ​​particularly advantageous in the field of agriculture. Indeed, when the composition according to the invention comprises such a mixture, the dissolution of the water-soluble matrix leads to the formation of pores in which microorganisms such as bacteria or microalgae can proliferate. The mass ratio of water-soluble biodegradable matrix to matrix biodegradable non-water-soluble can range from 5 / 95 to 95 / 5, for example from 20 / 80 to 80 / 20, such as from 40 / 60 to 60 / 40, for example 50 / 50.

[0037] Methods for preparing a porous object are also described herein, for example a method for forming a porous object comprising: a. prepare a composition according to the invention, in which the biodegradable matrix comprises a water-soluble biodegradable matrix and a non-water-soluble biodegradable matrix; b. expose the composition to an aqueous solution in order to dissolve at least part of the water-soluble biodegradable matrix, thus leaving pores in the composition.

[0038] Before implementation of step b), the process may include a step which consists of using the composition prepared in step a) to prepare an object for 3D printing, said composition preferably being used in the form of a 3D printer consumable.

[0039] In step b), the water-soluble biodegradable matrix is ​​extracted from the composition obtained in step a) or from the 3D-printed object by solubilizing it with an aqueous solution. This can be accomplished, for example, by simply immersing the object in water or an aqueous solution. The water-soluble biodegradable matrix does not need to be completely dissolved. However, the dissolved water-soluble biodegradable matrix leaves behind pores that make the object porous.

[0040] The process can make it possible to obtain a porous material having a porosity of at least 5%, for example 20%, such as 40%, 60% or 80%.

[0041] After the implementation of step b), the process according to the invention may include a step which consists of seeding the porous object obtained in step b) with microorganisms, for example bacteria or micro-algae.

[0042] Numerous bacteria of agronomic interest are described in the literature. Examples include: - Nitrogen-fixing bacteria, such as (i) non-symbiotic bacteria, for example Azotobacter, Azospirillum, Cyanobacteria, Beijerinckia and Clostridium and (ii) symbiotic bacteria, for example Rhizobium, Frankia which are associated with leguminous plants. - The bacteria soluble in phosphorus, tell us that Pseudomonas spp., Agrobacterium spp., Bacillus spp., Burkholderia, Micrococcus, Aerobacter, Azotobacter, Paenibacillus, Enterobacter, Rhodococcus, Serratia, Bradyrhizobium, Ralstonia, Rhizobium, Salmonella, Sinomonas and Thiobacillus. - The bacteria here soluble contain oligoelements, eg zinc, calcium, magnésium, selenium, molybdenum, cobalt, such as Pseudomonas aeruginosa, Gluconacetobacter diazotrophicus, Bacillus spp., Pseudomonas fluorescence, Pseudomonas striata, Burkholderia cenocepacia and Serratia. - The nitrifying bacteria, such as Nitrosomonas, Nitrosococcus, Nitrobacter, Nitrospina, Nitrospira and Nitrococcus. - The bacteria that soluble potassium, tell us that cidothiobacillus ferrooxidans, Paenibacillus spp., Bacillus mucilaginosus, B. edaphicus and B. circulans. - Bacteria that mitigate abiotic stresses, such as Pseudomonas, Bacillus, Rhizobium. In one embodiment, the mass percentage of biodegradable matrix in the composition according to the invention ranges from 30% to 99% by mass of the composition, for example from 40% to 95%, for example from 40% to 60%, for example from 40% to 50% by mass of the composition.

[0043] Since the biodegradable matrix is ​​suitable for 3D printing, it must have a particle size and physicochemical properties suitable for its use in 3D printing.

[0044] The biodegradable matrix has binding properties enabling it to bind the constituents of the composition, which allows the manufacture of the consumable according to the invention.

[0045] The biodegradable matrix will generally be chosen according to the desired characteristics and / or according to the nature of the charge.

[0046] The regolith charge can be prepared from natural or reconstituted regolith, that is, regolith prepared from terrestrial minerals. Generally, when the invention is implemented in space, for example on the Moon or Mars, the regolith is natural regolith directly collected from the ground. In one embodiment, the regolith is chosen from lunar or Martian regolith.

[0047] It is important that the regolith filler have a particle size suitable for 3D printing, for example, to prevent the composition from disintegrating, particularly when it is in consumable form. Preferably, the regolith filler has a particle size suitable for a 3D printing system that uses a 3D printing nozzle with an outlet diameter ranging from 0.2 to 1 mm. Thus, in a particular embodiment, the regolith filler has a particle size of less than 1 mm, preferably less than 0.5 mm, for example, less than 0.2 mm. The desired particle size can be obtained by sieving the regolith.

[0048] In particular embodiments, the mass percentage of regolith filler ranges from 1% to 80% by mass of the composition, for example from 5% to 80%, for example from 5% to 70%, for example the mass percentage is about 5%, about 50%, about 60%, about 70%.

[0049] It is known that regolith can have properties detrimental to plant growth, due to the formation of perchlorates under the effect of radiation. These perchlorates, which are cosmic, generate toxicity in plants. To avoid or reduce this perchlorate toxicity, the composition according to the invention may further include an anti-perchlorate compound. For example, the anti-perchlorate compound may be chosen from an agent providing nitrates that limit perchlorate toxicity, an agent whose formulation allows the incorporation of bacteria that inhibit perchlorate reduction, and / or a molecule that inhibits nitrate reductase. Furthermore, heating the composition according to the invention to a temperature between 200 and 300°C during 3D printing destroys the perchlorates and thus reduces or eliminates the toxicity of the regolith to plants.

[0050] In a particular embodiment, the composition according to the invention further comprises a fertilizing charge.

[0051] Fertilizers, or fertilizing materials, are substances, or mixtures of substances, natural or synthetic, used in agriculture to improve soils, particularly their structure, and to fertilize cultivated plants. Fertilizers include fertilizers and soil amendments. The former are intended to promote plant growth by supplying nutrients, while the latter are primarily intended to improve soil quality.

[0052] Fertilizers are generally available in liquid or solid form and can be applied to the soil or sprayed directly onto plants. Solid fertilizers are particularly preferred for providing plants with nutrients over the long term and limiting leaching, which is a drawback of liquid fertilizers. Solid fertilizers are produced using well-known industrial production methods such as pelletizing, compacting, and granulating.

[0053] It is important that the fertilizer charge has suitable thermal resistance for 3D printing. In particular, the fertilizer charge must retain its fertilizing properties after being subjected to melt extrusion and / or when heated in a 3D printing nozzle.

[0054] It is also important that the fertilizer charge has a particle size suitable for 3D printing. In a particular embodiment, the fertilizer charge has a particle size suitable for a 3D printing system that uses a 3D printing nozzle with an outlet diameter ranging from 0.2 to 1 mm. Advantageously, the fertilizer charge has a particle size of less than 1 mm, advantageously less than 0.5 mm, for example, less than 0.2 mm.

[0055] In a particular embodiment, the fertilizer load is chosen from: (i) phosphate (P), for example phosphate from a mine, such as natural phosphate, sedimentary phosphate or igneous phosphate. (ii) calcium carbonate (CAC), for example marine shellfish, (iii) struvite (VIT), for example struvite from the recycling of water from industrial processes, (iv) calcium sulfate (ANH), for example calcium sulfate from a mine, (v) diatomaceous earth (TE), (vi) biochar, or (vii) a mixture of several fertilizer loads selected from (i) to (vi).

[0056] In a particular embodiment, the mass percentage of fertilizer load ranges from 1% to 60% by mass of the composition, for example from 10% to 50% by mass of the composition.

[0057] In a particular embodiment, the composition according to the invention further comprises a porous filler. A porous filler is a filler containing a porous agent. This may consist of water-soluble particles.

[0058] Water-soluble particles may be water-soluble salt particles. For example, salts having a water solubility of at least 100 g / L at room temperature may be used. However, salts with lower water solubilities may also be used. Examples of water-soluble salts that may be included in compositions include inorganic metallic salts, such as copper-containing salts. Other water-soluble salts include water-soluble nitrates and sulfates (including copper sulfate), chlorides, bromides, and iodides; as well as water-soluble carbonates (including sodium carbonate, potassium carbonate, and ammonium carbonate) and hydroxides (including sodium hydroxide, potassium hydroxide, and ammonium hydroxide). The salt component can also be a mixture of any one of two or more of the salts mentioned above.

[0059] In a particular embodiment, the water-soluble salt particles are sodium chloride (NaCl) particles.

[0060] When the porogenous agent is a water-soluble particle, such as a water-soluble salt like NaCl, the porogenous charge may also include a water-soluble agent such as polyethylene glycol (PEB), for example PEG 8000.

[0061] Water-soluble particles can have a wide range of sizes and shapes, including both regular symmetrical shapes and irregular shapes. For example, they can be substantially spherical (i.e., spherical or very close to spherical, taking into account certain imperfections; for example, nanospheres or certain irregularly shaped granules), elongated cylindrical (for example, fibers, nanowires, and nanorods), plate-like (for example, sheets, flakes, and platelets) with dimensions ranging from 10 nm to 1 mm. For example, water-soluble salt particles can have diameters of at least approximately 10 nm, at least approximately 20 nm, at least approximately 100 nm, at least approximately 0.5 pm, and at least approximately 1 pm. The size of the water-soluble salt particles will affect the pore size in the material and, consequently, also the objects made from the material, for example, objects prepared by 3D printing. Therefore, the selected particle size will depend on the intended application of the objects. As an illustration, water-soluble salt particles with dimensions in the range of approximately 0.5 pm to approximately 22 pm, including the range of approximately 1 pm to 17 pm, can be used. As used here, the term "particles" refers to particles that comprise a solid material, as opposed to a liquid material (e.g., a droplet). However, the "particles" do not need to be completely solid throughout.For example, "particles" include porous particles and hollow particles.

[0062] The presence of a pore-forming agent in the composition according to the invention is particularly advantageous in the field of agriculture. Indeed, when the composition according to the invention includes a pore-forming filler, the vaporization or dissolution of the pore-forming filler leads to the formation of pores in which microorganisms such as bacteria can proliferate.

[0063] Methods for preparing a porous object are also described herein, for example a method for forming a porous object comprising: a. prepare a composition according to the invention comprising a porogen filler, preferably in which the mass percentage of porogen filler is at least 20% by mass of porogen filler relative to the total mass of the composition; b. exposing the composition to an aqueous solution to dissolve at least part of the pore-forming filler, thus leaving pores in the composition.

[0064] Before carrying out step b), the process may include a step of using the composition prepared in step a) to prepare a 3D printed object, said composition preferably being used in the form of a 3D printer consumable.

[0065] In step b), the porous filler is extracted from the composition obtained in step a) or from the 3D-printed object by solubilizing it with an aqueous solution. This can be accomplished, for example, by simply immersing the object in water or an aqueous solution. The porous filler does not need to be completely dissolved. However, the dissolved porous filler leaves behind pores that make the object porous.

[0066] The process according to the invention can make it possible to obtain a porous material having a porosity of at least 5%, for example 20%, such as 40%, 60% or 80%.

[0067] After implementation of step b), the process according to the invention may include a step consisting of inoculating the porous object obtained in step b) with microorganisms, for example bacteria or microalgae. Bacteria of agronomic interest are listed above.

[0068] The composition according to the invention can be obtained simply by mixing the desired quantities of its constituents in a suitably sized container to obtain a homogeneous mixture. To achieve satisfactory homogeneity of the composition, the mixture can be heated to an appropriate temperature, for example, while stirring.

[0069] In a particular embodiment of the invention, the composition according to the invention essentially consists of: - a biodegradable matrix, - a load of regolith, - possibly a fertilizer application, - possibly a porous load, and - possibly one or more other constituents chosen from among a colorant, a water-retaining agent, an anti-perchlorate compound and a microorganism, such as bacteria. The mass percentage of all these other constituents is generally less than 5% by mass of the composition, preferably less than 1%, for example less than 0.1%.

[0070] In one embodiment, the composition according to the invention has a mass percentage of filler / matrix ranging from 70 / 30 to 20 / 80, advantageously ranging from 60 / 40 to 30 / 70, for example of about 40 / 60, about 50 / 50, about 60 / 40.

[0071] In particular embodiments, the composition according to the invention essentially consists of: - Polybutylene adipate terephthalate (PBAT) and regolith, - Poly vinyl alcohol (PVA) and regolith, - Poly vinyl alcohol (PVA), regolith, calcium carbonate (CAC), - Poly vinyl alcohol (PVA), regolith, phosphate (P), - Polyvinyl alcohol (PVA), regolith, phosphate (P), calcium carbonate (CAC), - Polybutylene adipate terephthalate (PBAT), polyvinyl alcohol (PVA) and regolith, - Polybutylene adipate terephthalate (PBAT), glycerol-extruded sodium caseinate (LACTIPS) and regolith, - Polybutylene adipate terephthalate (PBAT), regolith and NaCl, or - Polybutylene adipate terephthalate (PBAT), regolith, NaCl and polyethylene glycol (PEG).

[0072] In a particular embodiment, the composition according to the invention essentially consists of: - A mass percentage of poly vinyl alcohol (PVA) ranging from 30% to 70%, for example ranging from 40% to 60%, a mass percentage of regolith ranging from 2% to 10%, for example about 5%, and a mass percentage of fertilizer load ranging from 25% to 70%, for example from 35% to 55%. - A mass percentage of polybutylene adipate terephthalate (PBAT) ranging from 20% to 60%, for example ranging from 30% to 50%, and a mass percentage of regolith ranging from 30% to 80%, for example from 50% to 70%. - A mass percentage of polybutylene adipate terephthalate (PBAT) ranging from 20% to 60%, for example from 40% to 55%, a mass percentage of polyvinyl alcohol (PVA) ranging from 30% to 70%, for example from 45% to 55%, and a mass percentage of regolith ranging from 2% to 10%, for example from approximately 5%. - A mass percentage of polybutylene adipate terephthalate (PBAT) ranging from 20% to 60%, for example from 40% to 55%, a mass percentage of glycerol-extruded sodium caseinate (LACTIPS) ranging from 30% to 70%, for example from 45% to 55%, and a mass percentage of regolith ranging from 2% to 10%, for example from approximately 5%. - A mass percentage of polybutylene adipate terephthalate (PBAT) ranging from 20% to 60%, for example ranging from 40% to 55%, a mass percentage of regolith ranging from 2% to 10%, for example about 5%, and a mass percentage of porogen filler ranging from 35% to 65%, for example ranging from 45% to 55%.

[0073] Compositions according to the invention are described in the tables below. [Tables 1] PVA (%m) Regolith (%m) Calcium carbonate (%m) Phosphate (%m) 40 5 27.5 27.5 50 5 22.5 22.5 60 5 17.5 17.5 [Tables 2] PBAT (%m) Regolith (%m) 50 50 40 60 30 70 [Tables 3] PBAT (%m) Regolith (%m) PVA (%m) Lactips (%m) NaCl (%m) PEG (%m) 40 5 55 50 5 45 40 5 55 50 5 45 40 5 45 10 50 5 36.8 8.2 51.5 4.4 39.7 4.4

[0074] Consumable for 3D printer

[0075] The composition according to the invention can be used to prepare a consumable, such as a filament, a cylinder or a granule.

[0076] Thus, the invention also relates to a 3D printer consumable having a composition according to the invention, such as a consumable in solid form, for example a filament, a cylinder, a granule or a film.

[0077] Filaments and granules are consumables commonly used in 3D printing; we then speak of filament for 3D printing and granules for 3D printing.

[0078] The composition is generally used as is to prepare the consumable. The consumable according to the invention can be prepared by any suitable process. For example, a filament can be obtained by extrusion from a composition according to the invention that has been heated to a temperature above its melting point.

[0079] Use and method

[0080] As described above, the composition and consumable according to the invention can be used by a 3D printer.

[0081] Thus, the invention also relates to the use of a composition according to the invention or a consumable according to the invention, for the preparation of a 3D printed object.

[0082] The invention also relates to a method for preparing a 3D printed object comprising the steps of: a) obtain a composition according to any one of claims 1 to 12 or a consumable according to claim 13; b) heat the composition or consumable from step a) in a 3D printing nozzle to obtain a molten composition or consumable; c) apply layer by layer the composition or molten consumable obtained in step b) onto a support using the 3D printing nozzle to form a 3D printed object.

[0083] The process makes it possible to prepare objects of variable geometric shape, for example tablecloth, sphere, truncated sphere, cube, pyramid, cylindrical stopper, etc.

[0084] The 3D printed object may have a homogeneous structure or have areas of different composition, for example a layer of composition A and a layer of composition B. For this, the process according to the invention may use several compositions or consumables of different compositions.

[0085] The 3D printed object can be solid or have cavities, for example a cavity in its center. It is also possible to add a liquid substance (of suitable viscosity) or solids (e.g., powder) inside the object.

[0086] The 3D printed object can display several colors when the process according to the invention uses several compositions or consumables of different colors.

[0087] The process is not limited to a particular substrate. Furthermore, any 3D printing nozzle can be used in the process of the invention, for example the e3D v6 nozzle (0.15 to 0.8 mm FDM extrusion). The 3D printing nozzle can be heated in order to heat the composition or consumable to a temperature above its melting point. Brief description of the figures

[0088] [Fig.l] Diagram showing the manufacturing steps of a filament-type consumable usable by a 3D printer.

[0089] [Fig.2] Study of the water solubility of matrices by immersion of matrix pellets in water, then filtration and weighing of the residual dry mass dissolved in the water at different immersion times. The water solubility of PVA (Mowiflex) is approximately 100% in excess water, the water solubility of sodium caseinate (Lactips) is approximately 80% in excess water and the water solubility of TPS (Potato Starch Polymer) is approximately 40% in excess water.

[0090] [Fig.3] Growth monitoring of the Bacillus Amyloliquefaciens strain.

[0091] [Fig.4] Growth monitoring of the Piriformospora Indica strain.

[0092] [Fig.5] Mixing couple tracking for formulations 1.

[0093] [Fig.6] Mixing couple tracking for formulations 2.

[0094] [Fig.7] Mixing couple tracking for formulations 3.

[0095] Examples

[0096] Example 1: Biodegradability of matrices

[0097] In a sterile environment, 100 mL of liquid carbon anogram medium is prepared, with the following composition:

[0098] [Tables4] Quantity: L-histidine 10 pg, D-methionine 20 pg, D-tryptophan 20 pg, Biotin 10 ng, Thiamine 1 pg, Pyrodoxine 1 pg, Calcium pantothenate 1 pg, Nicotinic acid 1 pg, Inositol 10 pg, Ammonium sulfate 5 g, Potassium dihydrogenate 1 g, Magnesium sulfate 0.5 g, Calcium chloride 0.1 g, Sodium chloride 0.1 g

[0099] Each matrix, previously reduced to powder (sole source of carbon), was then incorporated under stirring into the auxanogram medium at a rate of 5g per liter of medium.

[0100] The medium was then inoculated with 1 ml of a culture of microorganisms (Bacillus amyloliquefaciens or Piriformospora indica) at a concentration of 103 ufc / ml.

[0101] The assembly was incubated at 30°C with shaking at 120 rpm for 22 days.

[0102] Regular counts were carried out in order to determine the growth curve of the microorganism over time under the test conditions.

[0103] At each kinetic time point, a colony count was performed using a 1 ml sample of the liquid culture, which was cascade-diluted with 9 ml of tryptone salt diluent (dilutions in tenfold increments). Each dilution was applied at a rate of 1 ml per Petri dish and covered with Trypticase Soy Agar medium of the following composition (for IL): Tryptone 15 g / L, Soy Papain Peptone 5 g / L, Sodium Chloride 5 g / L, Agar 15 g / L (pH 7.3 + / - 0.2 at 25°C). After homogenizing the dishes before clumping, they were incubated in an incubator at 30°C for 48 hours. After 48 hours of incubation, the Petri dishes were read to count the number of colonies.

[0104] The matrices that were tested are: - polyvinyl alcohol (PVA 7001) and natural phosphate - poly vinyl alcohol (PVA C600) and natural phosphate; - plasticized starch (L001) and natural phosphate; - a natural copolymer plasticized with glycerol (TPS) and natural phosphate.

[0105] The number of colonies is representative of the matrix's ability to promote the growth of a microbial strain. In the absence of any other carbon source, the degradation of the plastic constitutes the sole source of carbon enabling microbial growth and multiplication.

[0106] The results are presented in Figures 3 and 4.

[0107] Conclusion

[0108] In the absence of other carbon sources than the tested matrices, microbial growth is made possible only by the consumption by bacteria of carbon from the matrices, thus confirming their biodegradability.

[0109] Example 2: Water solubility of matrices

[0110] Matrix pellets (0=14 mm - e=1 mm) were immersed in a sealed beaker in tap water (250 mL).

[0111] The matrices that were tested are: - A poly vinyl alcohol (Mowiflex C600), - A natural copolymer plasticized with glycerol (TPS Biotec), such as potato starch plasticized with glycerol, - A sodium caseinate extruded with glycerol (LACTIPS L0001).

[0112] Six pellets per matrix were independently immersed and stirred regularly. At different immersion times, a pellet sample was extracted from the test batch and the entire liquid contained in the relevant beaker was filtered through a cellulose filter (pore diameter = 2-3 pm).

[0113] The filter was then dried (50°C for 12 hours) and maintained at room temperature (23°C, 50% Relative Humidity, for 12 hours) before being weighed to determine the residual mass of matrix retained by the filter (residual pellets and potentially unsolubilized matrix particles present in the immersion liquid). All of these measurements made it possible to define the dissolution kinetics of the different matrix pellets as shown in [Fig. 2].

[0114] The residual mass of matrix retained by the filter is representative of its stability in water and therefore allows the matrices studied to be classified according to their water solubility. The higher the retained mass of matrix, the more water-soluble the matrix.

[0115] Conclusion

[0116] The mass loss over time of the different matrices immersed in water validates their water solubility. Depending on the types of matrices, the quantities and kinetics of solubilization are different.

[0117] Example 3: Compositions of interest for the production of filaments for FFF 3D printing

[0118] 3.1 Batch Formulation

[0119] A melt mixing campaign was carried out using a Brabender Rheocorder mixer. These formulations involve a small volume of approximately 55 cm3, allowing the production of usable samples for rheological or mechanical characterization, for example.

[0120] The mixer makes it possible to monitor the evolution of the mixing torque during the homogenization and melting phases of the materials. It also provides information on the stability and rheological homogeneity over time.

[0121] The compositions tested are of three different types and are detailed in Tables 5 to 7.

[0122] [Tables5] Ref. PVA C600 (%m) Regolith (%m) Ca Icium carbonate (%m) Phosphate (%m) R-Fl-1 40 5 27.5 27.5 R-Fl-2 50 5 22.5 22.5 R-Fl-3 60 5 17.5 17.5

[0123] [Tableauxô] Ref. PB AT (%m) Regolith (%m) PBAT (%v) Regolith (%v) R-F2-1 50 50 52.29 47.71 R-F2-2 40 60 42.22 57.78 R-F2-3 30 70 31.96 68.04

[0124] [Tables7] Ref. PBAT (%m) Regolith (%m) PVA C6 00 (%m) Lactips C aretips 3 00 (%m) NaCl (%m) PEG 8000 (%m) R-F3-1 40 5 55 R-F3-2 50 5 45 R-F3-3 40 5 55 R-F3-4 50 5 45 R-F3-5 40 5 45 10 R-F3-6 50 5 36.8 8.2 R-F3-7 51.5 4.4 39.7 4.4

[0125] The target matrix for the realization of the Fl formulations was polyvinyl alcohol (PVA) commonly used as a support material in FFF 3D printing.

[0126] The target matrix for the production of the F2 formulations was Polybutylene adipate terephthalate (PBAT), a biodegradable biopolyester. This material exhibits inherent flexibility, allowing for formulations with high filler content while ensuring implementation in filament form without risk of breakage.

[0127] The target matrix for the production of the F3 formulations was also PB AT, allowing both the introduction of the regolith filler and a porogenic agent. Two mixtures of water-soluble and water-insoluble matrices, as well as a porogenic agent, were evaluated for preparing a porous object: - the PB AT and PVA mixture, - the PB AT and Lactips® mixture. - PB AT and a NaCl type salt (Porogen agent).

[0128] The regolith used for the preparation of compositions 1, 2 and 3 was a reconstituted Martian regolith supplied by NASA (Reference: MMS-2 Enhanced Mars Regolith Simulant; Manufacturer: The Martian Garden). This reconstituted Martian regolith contains: 77% basalt powder (CAS Number 12765 06 9), 10% Fe2O3 (CAS Number 1309 37 1), 8% SiO2 (CAS Number 14808 60 7), 4% gypsum (CAS Number 13397 24 5) and 1% MgO (CAS Number 1309 42 8).

[0129] The mixing couple monitoring for the three series of formulations is illustrated in Figures 5 to 7.

[0130] Conclusion

[0131] It should be noted that the F3-3 formulation test highlighted a degradation of the porogen matrix comprising the Lactips matrix with the release of a phase The gaseous release was probably linked to the volatilization of plasticizers in the Lactips matrix. Therefore, formulation F3-4, with the same composition, was not produced.

[0132] On the other hand, formulations F3-5 and F3-6 revealed strong exudation of PEG 8000 in the form of wax. Since this surface migration is potentially detrimental to adhesion between successive deposits in FFF 3D printing, formulation F3-7 was developed for adjustment, reducing the amount of PEG 8000 in favor of the other porogenic agent, NaCl salt.

[0133] 3.2 Rheological tests

[0134] Following the batch formulations, rheological tests were initiated on the compositions of 3.1. For this purpose, a Göttfert RG20 capillary rheometer with an annular die D=2 mm and an L / D ratio of 30 was used. This characterization aimed to compare the viscosities of the compositions under a fixed shear stress in parallel with the recovery of filament samples to the standard diameter of 1.75 mm.

[0135] It became apparent from the initial tests that the material flow during this piston extrusion, carried out at a constant speed, was not stable for all the formulations tested. In addition, an obstruction of the extrusion die appeared during the test, preventing the production of a continuous, high-quality prototype filament.

[0136] It appears that the particle size (or the creation of aggregates during mixing) of the Regolithe was partly too high to ensure good implementation in the FFF 3D printing process.

[0137] A sieving of the Regolithe was therefore carried out with a 500 qm sieve in order to guarantee optimal quality for the formulations by twin-screw extrusion carried out subsequently.

[0138] The particle size distribution of the regolith was 71.3% of powders less than 500 µm and 28.7% of powders greater than 500 µm. Only the powder with a particle size less than 500 µm was used for the remainder of the study.

[0139] 3.3 Formulation by twin-screw extrusion

[0140] Following the batch formulations, taking into consideration the material yields obtained and the rheological stabilities during the mixing, the compositions R-Fl-3, R-F2-1 and R-F3-7 were selected.

[0141] For composition Fl, we selected composition R-Fl-3 because composition R-Fl-2 with 50% PVA gave off an acetic acid-like odor due to the beginning of PVA degradation. The filler introduced internal shear within the mixture, leading to matrix degradation. This degradation was significantly lower with the 60% PVA composition due to a shearing effect of the filler on the matrix.

[0142] The three selected compositions were used on a pilot scale (2 kg) for the purpose of manufacturing filaments for FFF 3D printing by twin-screw extrusion.

[0143] A TSA Model FSCM21 twin-screw co-rotating extruder – screw diameter 21 mm / L:D=40 – was used for this pilot production. All components of the compositions were oven-cured at 60°C for 12 hours to eliminate any potentially present moisture. The material feed (matrix in pellet form and filler in powder form) was carried out simultaneously in the main hopper using two Brabender gravimetric feeders. The extrusion rods were then granulated with a 3 mm cut using a MAAG Primo S60 granulator. The extrusion parameters for each formulation and process photographs are given in Table 8.

[0144] [Tables8] Ref. Temperature profile (°C) Z1-Z2-Z3-Z4-Z5-Z6- Z7-Z8 Screw speed (RPM) Overall dose rate r(kg / H) R-Fl-3 155-160-165-165-165- 160-155-155 300 3 R-F2-1 155-160-170-170-170- 165-165-160 300 3 R-F3-7 155-160-170-170-170- 165-165-165 300 3

[0145] 3.4 Filament spinning

[0146] Following pilot production by twin-screw extrusion, the compositions were spun by single-screw extrusion to the 1.75mm diameter standard used for FFF 3D printing. Due to the reduced quantity of Regolithe related to the necessary sieving (compound present in all three formulations), it was preferred to use a small 3D Evo extrusion line - Advanced 1.0 model (screw diameter = 16 mm - L:D=20) to the Scamex pilot line (screw diameter = 20mm - L:D=20) initially targeted for this step.

[0147] In this way, the maximum amount of material can be transformed into filament while limiting losses related to start-up phases and the dead volume inherent in the extruder. The extrusion parameters are given in Table 9.

[0148] [Tables9] Ref. Screw Speed ​​(RPM) Feeder Speed ​​Filament Diameter Temperature Profile (°C) Z1-Z2-Z3-Z4 R-Fl-3 3.4 Auto 1.75 185-185-185-185 R-F2-1 4.4 Auto 1.75 150-155-155-150 R-F3-7 10.5 Auto 1.75 144-157-145-142

[0149] 3.5 3D printing tests

[0150] Following the pilot production of filaments from the three selected compositions, FFF 3D printing tests were conducted. A series of prints made it possible to determine the optimal printing parameters for each reference.

[0151] A Creality CRI OS Pro-V2 printer equipped with an E3D Titan - Direct Drive 1.75mm extruder was used for this study. Extrusion tests over a temperature range of 180 to 240°C were conducted beforehand to determine the minimum temperature guaranteeing a consistent flow rate for the three selected formulations. Subsequently, different nozzles with diameters of 400, 600, 800, and 1000 µm were tested to identify the best compromise between the fineness and consistency of the deposition of each material. Similarly, different printing speeds from 5 to 30 mm / s were evaluated to determine the optimal speed for high-quality material deposition.

[0152] Table 10 lists the optimized parameters for each composition.

[0153] [TableauxlO] Ref. Printing Speed ​​(mm / s) Nozzle Temperature (°C) Bed Temperature (°C) Nozzle Diameter (sqm) Layer Height (sqm) Layer Width (sqm) R-Fl-3 15 230 50 800 300 500 to 850 R-F2-1 15 210 50 800 300 500 to 850 R-F3-7 8.5 195 30 800 300 500 to 850

Claims

Demands

1. Composition for three-dimensional (3D) printing comprising: - a biodegradable matrix, and - a regolith filler, wherein the biodegradable matrix is ​​a mixture of a water-soluble biodegradable matrix and a non-water-soluble biodegradable matrix.

2. Composition according to claim 1, wherein the water-soluble biodegradable matrix is ​​selected from poly vinyl alcohol (PVA), polylactide (PLA), a natural plasticizer-free copolymer plasticized with glycerol, glycerol-extruded sodium caseinate (LACTIPS).

3. Composition according to any one of claims 1 or 2, wherein the non-water-soluble biodegradable matrix is ​​selected from polybutylene adipate terephthalate (PBAT), polyhydroxyalkanoate (PHA) and poly-[3-hydroxybutyrate (PHB), such as poly(3-hydroxybutyrate-co-3-hydroxyhexanoate (PHBH) or polyhydroxybutyrate-valerate (PHBV).

4. Composition according to any one of claims 1 to 3, wherein the biodegradable matrix is ​​a mixture of poly vinyl alcohol (PVA) and polybutylene adipate terephthalate (PBAT).

5. Composition according to any one of claims 1 to 4, wherein the regolith is selected from a lunar regolith or a Martian regolith.

6. Composition according to any one of claims 1 to 5, wherein the regolith filler has a particle size of less than 1 mm, advantageously less than 0.5 mm.

7. Composition according to any one of claims 1 to 6, wherein the composition further comprises a fertilizer load

8. Composition according to claim 7, wherein the fertilizer charge has a particle size of less than 1 mm, advantageously less than 0.5 mm.

9. Composition according to any one of claims 7 or 8, wherein the fertilizer load is selected from: (i) phosphate (P), (ii) calcium carbonate (CAC), (iii) struvite (VIT), (iv) calcium sulfate (ANH), (v) diatomaceous earth (TD), (vi) biochar, or (vii) a mixture of several fertilizer fillers selected from (i) to (vi).

10. Composition according to any one of claims 1 to 9, wherein the composition further comprises a porogenous filler.

11. Composition according to any one of claims 1 to 10, wherein the mass percentage filler / matrix ranges from 70 / 30 to 20 / 80, for example ranges from 60 / 40 to 30 / 70, for example is about 40 / 60, about 50 / 50, about 60 / 40.

12. Composition according to any one of claims 1 to 3 and 5 to 11, said composition being essentially composed of: (i) Polybutylene adipate terephthalate (PBAT), Poly vinyl alcohol (PVA) and regolith, ii) Polybutylene adipate terephthalate (PBAT), glycerol-extruded sodium caseinate (LACTIPS) and regolith.

13. Consumable for 3D printer having a composition according to any one of claims 1 to 12.

14. Use of a composition according to any one of claims 1 to 12, or of a consumable according to claim 13, for the preparation of a 3D printed object.

15. A method for preparing a 3D printed object comprising the steps of: a) obtaining a composition according to any one of claims 1 to 12 or a consumable according to claim 13; b) heating the composition or consumable from step a) in a 3D printing nozzle to obtain a molten composition or consumable; c) applying layer by layer the molten composition or consumable obtained in step b) onto a support using the 3D printing nozzle to form a 3D printed object.

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