Additive manufacturing composition

Abstract

To provide a composition that is a solid material containing a protein as a raw material and that can be used as a material for additive manufacturing.SOLUTION: Provided is an additive manufacturing composition containing a protein, glycerin, and a cellulose derivative. The additive manufacturing composition may have a water content of less than 20 mass%. The additive manufacturing composition is preferably used as a material for additive manufacturing using fused deposition modeling or sheet lamination. The material is preferably supplied as a melt-kneaded product or a molded product thereof.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to additive manufacturing compositions. [Background technology]

[0002] Additive manufacturing is defined as "a process of creating an object from a numerical representation of a three-dimensional structural shape by depositing material" (ASTM International definition). Generally, it is a technology that uses a 3D printer to build up materials to create three-dimensional objects. Additive manufacturing is sometimes categorized into seven methods: 1) bath photopolymerization, 2) powder bed fusion bonding, 3) binder jetting, 4) fused deposition modeling (also known as material extrusion), 5) material jet deposition, 6) directed energy deposition, and 7) sheet lamination.

[0003] Of these methods, 4) fused deposition modeling is a method in which a liquid or plasticized solid material is extruded from a nozzle, deposited, and then solidified and welded. In fused deposition modeling, a "material formed into a continuous thread-like fiber," generally called a filament, is often supplied to the nozzle and extruded from the nozzle.

[0004] 7) The sheet lamination method is a method of manufacturing a three-dimensional object by laminating solid materials formed into sheets (or tapes), and applying energy (heating with a heating roller, or heating with ultrasonic waves or infrared radiation, etc.) during lamination to weld the sheets together.

[0005] Additive manufacturing, which uses a 3D printer to build materials into three-dimensional objects, is a technology applied in a variety of fields. In recent years, its application in the medical and healthcare fields has been attracting particular attention (see Non-Patent Document 1). To apply additive manufacturing technology to the medical and healthcare fields, biocompatibility and other factors are required for the materials being built. Examples of additive manufacturing applied to the medical and healthcare fields include those described in Patent Documents 1 to 3. Patent Document 1 proposes additive manufacturing of articles using fused deposition modeling from materials containing biodegradable and biocompatible polymers, such as water-insoluble ethyl cellulose. Patent Document 2 discloses the production of meat analogs as food products using 3D printing from materials containing protein-based and fat-based components. Patent Document 3 also discloses a technology for molding pharmaceutical formulations from materials containing active pharmaceutical ingredients and thermoplastic polymers using fused deposition modeling, without producing filaments from the materials.

[0006] Furthermore, polylactic acid is generally known as a biodegradable plastic material, but other technologies have also been proposed, including plastic materials made from polysaccharides or proteins (Non-Patent Document 2). [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Special Publication No. 2018-526246 [Patent Document 2] Special Publication No. 2022-517863 [Patent Document 3] Japanese Patent Application Publication No. 2023-146845 [Non-patent literature]

[0008] [Non-Patent Document 1] Japan Patent Office: FY2019 Patent Application Technology Trends Survey Results Summary: 3D Printers [Non-patent document 2] Recent Trends in Protein-Based Plastics, Chemistry and Biology, Vol. 41, No. 11, pp. 728-730 (2003) Summary of the Invention [Problem to be solved by the invention]

[0009] As described above, additive manufacturing using fused deposition modeling (also known as material extrusion) generally involves converting a solid material into fibrous material called a filament and extruding it while heating it. When converting a solid material into a filament, the filament diameter can be uneven or the filament can be brittle, making it insufficient as a material for fused deposition modeling. Similarly, additive manufacturing using sheet deposition involves forming a solid material into sheets and then laminating them. When converting a solid material into a sheet, the sheet thickness can be uneven or the sheet can be brittle, making it insufficient as a material for sheet deposition modeling.

[0010] In particular, solid materials containing proteins (especially plant-derived proteins) are expected to be biodegradable and biocompatible, but they are often difficult to mold into filaments or sheets, and it has been found that they may not be applicable to three-dimensional modeling by additive manufacturing. For this reason, there is a demand for the development of solid materials containing proteins as materials and compositions that can be used as materials for additive manufacturing. [Means for solving the problem]

[0011] The present invention relates to an additive manufacturing composition having, for example, the following aspects: [1] A composition for additive manufacturing containing a protein, glycerin, and a cellulose derivative.

[0012] The present invention preferably relates to an additive manufacturing composition of the following aspects: [2] The composition according to [1], wherein the additive manufacturing is by fused deposition modeling or sheet lamination. [3] The composition according to [1] or [2], wherein the cellulose derivative comprises a water-soluble cellulose derivative. [4] The composition described in [3] above, wherein the water-soluble cellulose derivative comprises hydroxypropyl cellulose. [5] The composition according to any one of [1] to [4] above, wherein the protein comprises a plant-derived protein. [6] The composition described in [5] above, wherein the plant-derived protein comprises at least one protein selected from the group consisting of soybean-derived protein, adzuki bean-derived protein, kidney bean-derived protein, cocoa bean-derived protein, wheat-derived protein, buckwheat-derived protein, and rice-derived protein. [7] The composition according to any one of the above [1] to [6], wherein the water content is less than 20% by mass.

[0013] [8] The composition according to any one of the above [1] to [7], which is a melt-kneaded product. [9] The composition according to any one of the above [1] to [8], which is a molded product of a melt-kneaded mixture. [Effects of the Invention]

[0014] The additive manufacturing composition of the present invention has excellent processability (including molding processability) despite containing a protein as a material. Therefore, it is useful as a material for additive manufacturing, particularly as a material for fused deposition modeling and sheet lamination. Furthermore, because the additive manufacturing composition of the present invention uses a protein as a material, it is likely to be biocompatible and biodegradable. Therefore, it is suitable as a material for manufacturing various items, including those in the medical and healthcare sectors, by additive manufacturing. [Brief explanation of the drawings]

[0015] [Figure 1] 3D printed model 1 printed in the example is shown. [Figure 2] 3D printed model 2 printed in the example is shown. [Figure 3] Photograph of a structure (additive manufactured product) obtained by printing a 3D print model 1 using the additive manufacturing composition of the present invention as a material. [Figure 4] Photograph of a structure (additive manufactured product) obtained by printing a 3D print model 2 using the additive manufacturing composition of the present invention as a material. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, embodiments of the present invention will be described in detail.

[0017] 1. Additive Manufacturing Compositions The additive manufacturing composition of one embodiment of the present invention contains a protein, glycerin, and a cellulose derivative, and may further contain any other components.

[0018] [1-1. Protein] In the composition of the present invention, the protein is not particularly limited, but is generally a protein classified as a "structural protein." The protein may be a plant-derived protein or an animal-derived protein. The protein may be a pure protein, a denatured protein (e.g., heat-denatured protein, pressure-denatured protein, hydrolyzed protein), a protein isolate, a protein concentrate, a protein powder, etc.

[0019] Plants from which plant-derived proteins are derived are not particularly limited, and examples include grains, beans, nuts and seeds, potatoes, vegetables, fruits, mushrooms, algae, etc. Examples of grains include wheat, barley, oats, rice, corn, buckwheat, etc. Examples of beans include soybeans, peas, adzuki beans, chickpeas, lentils, fava beans, mung beans, lupin beans, kidney beans, cocoa beans, etc. Examples of nuts and seeds include almonds, peanuts, cashew nuts, pistachios, hazelnuts, macadamia nuts, flaxseed, sesame, rapeseed, cottonseed, safflower, sunflower, etc. Examples of potatoes include potatoes, sweet potatoes, mountain yams, Jerusalem artichokes, cassava, etc. Examples of vegetables include asparagus, artichokes, cauliflower, broccoli, edamame, etc. Examples of fruits include bananas, jackfruits, kiwifruits, coconuts, avocados, olives, etc. Examples of mushrooms include mushrooms, king oyster mushrooms, shiitake mushrooms, shimeji mushrooms, maitake mushrooms, etc. Examples of algae include chlorella, spirulina, euglena, nori, kelp, wakame seaweed, hijiki seaweed, tengusa seaweed, mozuku seaweed, etc.

[0020] Plant-derived proteins include proteins contained in fermented products made from plants (for example, rice-derived proteins such as proteins contained in sake lees made from rice) and denatured proteins extracted from plants (for example, heat-denatured proteins, pressure-denatured proteins, and hydrolyzed proteins).

[0021] On the other hand, examples of animal-derived proteins include collagen, gelatin, keratin, casein, and whey protein.

[0022] In the additive manufacturing composition of the present invention, the protein is preferably a plant-derived protein, and particularly preferably a soybean-derived protein, azuki bean-derived protein, kidney bean-derived protein, cocoa bean-derived protein, wheat-derived protein, buckwheat-derived protein, or rice-derived protein. The protein can be used alone or in combination of two or more types.

[0023] In the additive manufacturing composition of the present invention, the upper limit of the protein content is preferably 85% by mass, more preferably 80% by mass, and particularly preferably 75% by mass, relative to the total amount of the composition. When the protein content is 85% by mass or less, sufficient moldability can often be imparted to the composition. The lower limit of the protein content is not particularly limited and may be set appropriately depending on the application of the additive product to be obtained, but is preferably 10% by mass, more preferably 15% by mass, and particularly preferably 20% by mass, relative to the total amount of the composition. It is believed that the higher the protein content, the more likely it is that the biodegradability and biocompatibility of the additive manufacturing composition can be improved.

[0024] [1-2. Glycerin] The additive manufacturing composition of the present invention contains glycerin (also called glycerol). The glycerin enhances the processability of the additive manufacturing composition, making it easier to mold it into filaments, sheets, and the like. Therefore, the composition of the present invention can be effectively used as a material applicable to additive manufacturing using fused deposition modeling or sheet lamination.

[0025] In the composition of the present invention, the lower limit of the glycerin content is preferably 10% by mass, more preferably 15% by mass, and even more preferably 20% by mass, based on the total mass of the composition. The upper limit of the glycerin content is preferably 85% by mass, more preferably 80% by mass, and even more preferably 75% by mass, based on the total mass of the composition. Furthermore, the weight ratio of glycerin to protein (glycerin:protein) in the composition of the present invention is preferably 25:75 to 80:20, more preferably 30:70 to 80:20, even more preferably 35:65 to 80:20, and particularly preferably 40:60 to 75:25.

[0026] [1-3. Cellulose derivatives] The additive manufacturing composition of the present invention contains a cellulose derivative. Because cellulose derivatives are thermoplastic, the cellulose derivatives enhance the moldability of the additive manufacturing composition, making it easier to mold into filaments, sheets, and the like, making it a material suitable for additive manufacturing. Furthermore, additive manufacturing compositions containing cellulose derivatives also have enhanced thermal solubility or thermoplasticity, making them easier to weld in three-dimensional modeling during additive manufacturing, and facilitating three-dimensional modeling.

[0027] The cellulose derivative is preferably water-soluble. Examples of water-soluble cellulose derivatives include methyl cellulose, hydroxypropyl cellulose, hydroxypropyl cellulose, carboxymethyl cellulose, and ethyl cellulose with a low ethoxylation rate (preferably an ethoxylation rate of 40% by mass or less), with hydroxypropyl cellulose being particularly preferred.

[0028] In the composition of the present invention, the lower limit of the content of the cellulose derivative (preferably a water-soluble cellulose derivative) is preferably 1% by mass, more preferably 3% by mass, and even more preferably 5% by mass, based on the total amount of the composition. When the content of the cellulose derivative is 1% by mass or more, the moldability of the composition tends to be improved. On the other hand, the upper limit of the content of the cellulose derivative (preferably a water-soluble cellulose derivative) is preferably 50% by mass, more preferably 40% by mass, and even more preferably 30% by mass, based on the total amount of the composition.

[0029] The reason why the cellulose derivative in the additive manufacturing composition of the present invention increases the moldability of the composition is not particularly limited, but it is thought that the cellulose derivative is not miscible with proteins, is dispersed in the additive manufacturing composition, and relaxes the strength of the protein network that constitutes the additive manufacturing composition.

[0030] [1-4. Other ingredients] The additive manufacturing composition of the present invention may contain polyols other than glycerin and cellulose derivatives (other polyols); and may also contain solvents, active pharmaceutical ingredients, nutritional ingredients other than proteins, pH adjusters, lubricants, antioxidants, colorants, flavorings, sweeteners, stabilizers, fragrances, etc., depending on the purpose and use of the additive product to be obtained.

[0031] [1-4-1. Other polyols] The additive manufacturing composition of the present invention may further contain a polyol other than glycerin and cellulose derivatives, which may facilitate molding into filaments or sheets or heat dissolution. Examples of such polyols include monoesters of fatty acids with glycerin or polyglycerin, such as glyceryl monocaprylate, glyceryl monobehenate, glyceryl monopalmitate, glyceryl monostearate, glyceryl monobehenate, and polyglyceryl monostearate; (poly)alkylene glycols, such as ethylene glycol, propylene glycol, polyethylene glycol, and polypropylene glycol; aminopolysaccharides, such as chitosan; and sugar alcohols, such as erythritol, xylitol, sorbitol, mannitol, maltitol, and trehalose.

[0032] [1-4-2. Solvent] The solvent contained in the additive manufacturing composition of the present invention may be water or an organic solvent such as ethanol, isopropyl alcohol, ethyl butyrate, etc. The other components such as solvents may be used alone or in combination of two or more.

[0033] Conventionally, compositions for producing processed foods such as meat substitutes by additive manufacturing (for example, using a 3D printer) have contained a considerable amount of water (see, for example, Patent Document 2). On the other hand, in the composition of the present invention, the water content is preferably less than 20% by mass, more preferably less than 15% by mass, even more preferably less than 10% by mass, and particularly preferably less than 5% by mass, based on the total amount of the composition. Apart from water contained in plant-derived protein raw materials and other water brought in with other ingredients, no water needs to be added.

[0034] By reducing the water content, it is possible to obtain a three-dimensional object with excellent storage stability, and it is also possible to shorten or eliminate the drying process after printing.

[0035] [1-5. Physical properties of additive manufacturing compositions] The additive manufacturing composition of the present invention preferably has a melting point of 130 to 170°C. In other words, the additive manufacturing composition preferably has a melting point that allows it to be melted during additive manufacturing. Furthermore, since the additive manufacturing composition needs to flow smoothly during additive manufacturing, it is desirable for its viscosity when melted to be low. Specifically, at the heating temperature during additive manufacturing, the melt flow rate (MFR), which corresponds to the viscosity when melted, is preferably 1 g / 10 min or more. The measurement method for the melt flow rate is specified in ISO 1133-1:2011, JIS K7210-1:2014, etc., and is an index for evaluating the fluidity of a resin; a higher value indicates a lower viscosity when melted.

[0036] [2. Manufacturing method of additive manufacturing composition, etc.] The additive manufacturing composition of the present invention can be produced, for example, by a method including the following steps: 1) a mixing step of mixing a protein, glycerin, a cellulose derivative, and other components; 2) a melt-kneading step of melt-kneading the mixture obtained in the mixing step while compressing it; and 3) a molding step of molding the molten mixture obtained in the melt-kneading step.

[0037] The mixing step may be carried out using a mixer such as a mixer, and there are no particular limitations on the type of mixer. The melt-kneading step may be carried out using an extruder. There are no particular limitations on the type of extruder, and either a single-screw or twin-screw type may be used, although twin-screw types that can perform kneading and extrusion may be preferred. The temperature during kneading (melting temperature) is not particularly limited, but is preferably 50°C or higher for efficient kneading, and may be 70°C or higher. On the other hand, the temperature during kneading (melting temperature) is preferably 200°C or lower, more preferably 170°C or lower, to prevent protein decomposition.

[0038] The molding process can be carried out by extruding the molten mixture through the die of an extruder. Depending on the shape of the die slit, a molded product of any shape can be obtained, and it can be formed into a fibrous filament or sheet. The diameter of the filament is approximately 0.5 mm to 5 mm, and the thickness of the sheet is approximately 0.1 mm to 1 mm, but is not particularly limited.

[0039] [3. Additive manufacturing methods] The additive manufacturing composition of the present invention can be used as a material for additive manufacturing. The additive manufacturing method is not particularly limited, and known methods such as fused deposition modeling (FDM), sheet lamination, binder jetting, material jetting, directed energy deposition, powder bed fusion, and liquid vat photopolymerization can be used.

[0040] The additive manufacturing composition of the present invention has high moldability and can be easily molded into filaments or sheets. Therefore, the additive manufacturing method using the additive manufacturing composition of the present invention as a material is preferably fused deposition modeling or sheet lamination. That is, in the case of fused deposition modeling, the composition of the present invention can be made into a filament, and in the case of sheet lamination, the composition of the present invention can be made into a sheet. Furthermore, since the composition of the present invention also has excellent thermal solubility, it is particularly preferable to adopt fused deposition modeling as the additive manufacturing method.

[0041] In the fused deposition modeling method, a material containing a thermoplastic polymer processed into a linear shape, called a filament, is typically heated and melted while being extruded through a nozzle for lamination (see, for example, the examples in Patent Document 1). This filament can be used as the composition of the present invention. Meanwhile, as disclosed in Patent Document 3, a method is also known in which a molten mixture containing a thermoplastic polymer is extruded and laminated without producing a filament. This molten mixture can also be used as the composition of the present invention.

[0042] In the fused deposition modeling, the temperature (for example, nozzle temperature) when the composition of the present invention is extruded is preferably 130 to 250° C., particularly preferably 150 to 200° C. The infill density can be set in the range of 10 to 100% depending on the application of the resulting additive product.

[0043] [4. Additive Manufacturing] Additive manufactured products obtained using the additive manufacturing composition of the present invention are composed of protein-containing materials and are therefore expected to be biocompatible and biodegradable, and can be used primarily as products in the medical and healthcare fields. Examples of such products include processed foods such as meat substitutes, pharmaceuticals and health foods in solid dosage forms, pet supplies, and biodegradable packaging materials and containers. [Example]

[0044] The present invention will be described in detail below with reference to examples, but the present invention should not be construed as being limited to the following examples.

[0045] [Example 1] A. Filament Preparation 45 parts by mass of Wilpro N10 (manufactured by Wilmar, protein content 86.4% by mass, moisture content 5.6% by mass) containing soy protein, 45 parts by mass of glycerin, and 10 parts by mass of hydroxypropyl cellulose (Cerny SL, manufactured by Nippon Soda Co., Ltd.) were mixed and then fed into a twin-screw extruder, where the mixture was kneaded while heated. The kneaded product was extruded through a filament die with a diameter of 3 mm. The barrel temperatures were set to 90°C in the feed section (directly below the raw material input section), 130°C in the center, and 130°C at the tip. The screw rotation speed was 8 rpm.

[0046] B. Evaluation of moldability of molded products The appearance of the extruded product was observed, and the moldability was evaluated according to the following criteria. The evaluation results are shown in Table 1. ◎: Fluid and discharged in filament (fiber) form without breaking ○: Ribbon-like products are discharged connected together (they do not form filaments but are welded together to form flat strings) △: Ribbon-shaped product is discharged while being torn into pieces ×: Discharged in flake form.

[0047] [Comparative Examples 1 to 3] Molded products were prepared in the same manner as in Example 1, except that the types and amounts of each component were changed as shown in Table 1, and their moldability was evaluated. The evaluation results are shown in Table 1.

[0048] [Table 1]

[0049] Wilpro N10: Contains 86.4% soy protein by mass, 5.6% moisture by mass, and 3.6% carbohydrates by mass (manufactured by Wilmar) HPC: Hydroxypropyl cellulose (Cerny SL, manufactured by Nippon Soda Co., Ltd.)

[0050] The molded product of Comparative Example 1 was composed of protein-containing Wilpro N10 and glycerin, but its appearance was ribbon-like, not filament-like. In contrast, the filament of Example 1 contained hydroxypropyl cellulose in addition to protein-containing Wilpro N10 and glycerin, but its appearance was filament-like. Thus, it can be seen that the addition of hydroxypropyl cellulose improved the moldability.

[0051] On the other hand, Comparative Examples 2 and 3 contain polyvinyl alcohol or maltitol together with the protein-containing Wilpro N10 and glycerin, but the appearance of the product is not filament-like, but is torn or broken into pieces. This shows that the addition of polyvinyl alcohol and maltitol reduces the moldability.

[0052] C. Melt flow properties of filaments Because filaments used in additive manufacturing must exhibit high fluidity when melted at high temperatures, fluidity was evaluated according to the method specified in JIS K7210-1:2014, "Determination of Melt Mass-Flow Rate (MFR) and Melt Volume-Flow Rate (MVR) of Plastics - Thermoplastics." Five grams of the molded product (filament) from Example 1 was placed in a cylindrical extrusion plastometer, heated to 150°C, pressurized with a 2.16 kg load, and after 300 seconds of preheating, the molten composition was extruded from the die opening at the bottom of the container. The extruded material was collected three times every 10 seconds, with the resulting masses being 0.0779 g, 0.0733 g, and 0.0709 g. The melt mass-flow rate (MFR) (expressed in grams per 10 minutes) calculated using the following formula was 4.4 g / 10 min. (Number 1) MFR = (600×m) / t m: average mass of recovered pieces (g) t: sample collection time interval (seconds) 600: Coefficient for converting grams per second to 10 minutes (600 seconds)

[0053] On the other hand, the molded products obtained in Comparative Examples 1, 2, and 3 were judged to be too viscous to be measurable because no extrusion was obtained using the same procedure. For reference, the MFR was calculated using the same procedure using PLA (polylactic acid plastic, manufactured by Sunlu), which is commonly used as a filament in additive manufacturing, and was found to be 9.8 g / 10 min.

[0054] D. Additive Manufacturing from Filaments (Fused Deposition Modeling) 1 and 2 are diagrams of 3D printed models 1 and 2 according to some non-limiting examples of the present disclosure. 3D printed model 1 is a square shape measuring 10 mm x 10 mm x 4 mm with a wall thickness of 1 mm. 3D printed model 2 is a flat plate shape measuring 10 mm x 10 mm x 1 mm. For these 3D printed models, STL files were created using Autodesk Fusion 360 software, and G-code was created from the STL files using Ultimaker Cura software.

[0055] The product (filament) obtained in Example 1 was supplied to a 3D printer (Entina Tina2S), and the printing conditions were set to a nozzle temperature of 170°C, a printing speed of 40 mm / s, and an infill density of 100%, and the product was ejected from the nozzle (injection port inner diameter: 0.4 mm) to print 3D printed model 1. As a result, the square-shaped structure shown in Figure 3 was obtained.

[0056] The product (filament) obtained in Example 1 was supplied to a 3D printer (Entina Tina2S), and the printing conditions were set to a nozzle temperature of 200°C, a printing speed of 40 mm / s, and an infill density of 100%, to print a 3D printed model 2. As a result, a flat structure as shown in Figure 4 was obtained.

[0057] The ribbon-like product obtained in Comparative Example 1 was cut into filament-like material, which was then supplied to a 3D printer. The printing conditions were set to a nozzle temperature of 170°C, a printing speed of 40 mm / s, and an infill density of 100%, and 3D printed model 2 was printed. As a result, the film material was not ejected from the nozzle, and a structure could not be formed. [Industrial Applicability]

[0058] The additive manufacturing composition of the present invention can be used as a material for various additive manufacturing processes, particularly as a material for additive manufacturing using fused deposition modeling or sheet deposition modeling. Furthermore, since the additive manufacturing composition of the present invention contains proteins, it is likely to be biocompatible and biodegradable, making it particularly effective as a material for additive manufacturing of medical and healthcare products, and additive manufacturing of foods and daily necessities.

Claims

1. An additive manufacturing composition comprising a protein, glycerin, and a cellulose derivative.

2. The composition of claim 1 , wherein the additive manufacturing is by fused deposition modeling or sheet lamination.

3. The composition of claim 1 or 2, wherein the cellulose derivative comprises a water-soluble cellulose derivative.

4. The composition of claim 3 , wherein the water-soluble cellulose derivative comprises hydroxypropyl cellulose.

5. The composition of claim 1 or 2, wherein the protein comprises a plant-derived protein.

6. 6. The composition according to claim 5, wherein the plant-derived protein comprises at least one protein selected from the group consisting of soybean-derived protein, adzuki bean-derived protein, kidney bean-derived protein, cocoa bean-derived protein, wheat-derived protein, buckwheat-derived protein, and rice-derived protein.

7. The composition according to claim 1 or 2, wherein the water content is less than 20% by mass.

8. The composition according to claim 1 or 2, which is a melt-kneaded product.

9. The composition according to claim 1 or 2, which is a molded product of a melt-kneaded product.

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