Composition for three-dimensional modeling

Abstract

To provide a composition for three-dimensional modeling, capable of being favorably injected from a nozzle.SOLUTION: A composition for three-dimensional modeling to be injected by a three-dimensional modeling apparatus or an injection molding apparatus comprises inorganic particles, at least a part of a surface of which is modified with resin. The resin is an acrylate-based resin, is not a copolymer resin of acrylate and methacrylate, and has a glass transition temperature of 8.6°C or higher and 71.3°C or lower.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to a composition for three-dimensional modeling. [Background technology]

[0002] BACKGROUND ART Compositions for three-dimensional modeling that are injected by a three-dimensional modeling device or an injection molding device are known.

[0003] For example, Patent Document 1 describes a thermofusible filament containing an inorganic powder and a binder, which is heated and ejected from a nozzle to form a three-dimensional object. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 2017-530029 Summary of the Invention [Problem to be solved by the invention]

[0005] It is desirable for the above-mentioned hot melt filaments to be ejected smoothly from the nozzle. [Means for solving the problem]

[0006] One aspect of the composition for three-dimensional formation according to the present invention is A composition for three-dimensional modeling that is injected by a three-dimensional modeling device or an injection molding device, The inorganic particles have at least a portion of their surfaces modified with a resin; The resin is an acrylate-based resin, not a copolymer resin of acrylate and methacrylate, The glass transition temperature is 8.6°C or higher and 71.3°C or lower. [Brief explanation of the drawings]

[0007] [Figure 1]FIG. 1 is a cross-sectional view schematically illustrating a composition for three-dimensional formation according to an embodiment of the present invention. [Figure 2] FIG. 2 is a diagram schematically illustrating a method for modifying the surface of inorganic particles with a resin. [Figure 3] FIG. 1 is a cross-sectional view schematically illustrating a composition for three-dimensional formation according to an embodiment of the present invention. [Figure 4] Graph showing the interaction of TMCHA polymer with linear saturated fatty acids. [Figure 5] This table shows the range of carbon numbers of linear saturated fatty acids that have good interactions with monomers for forming resins. [Figure 6] FIG. 1 is a cross-sectional view schematically illustrating a composition for three-dimensional formation according to an embodiment of the present invention. [Figure 7] FIG. 1 is a cross-sectional view schematically showing a three-dimensional modeling apparatus that uses a composition for three-dimensional modeling according to an embodiment of the present invention. [Figure 8] 1 is a table showing the production conditions and experimental results of Examples 1 to 6 and Comparative Examples 1 to 3. DETAILED DESCRIPTION OF THE INVENTION

[0008] Preferred embodiments of the present invention will be described in detail below with reference to the drawings. Note that the embodiments described below do not unduly limit the content of the present invention as defined in the claims. Furthermore, not all of the configurations described below are necessarily essential components of the present invention.

[0009] 1. Composition for three-dimensional modeling First, the composition for forming a three-dimensional object according to this embodiment will be described with reference to the drawings. Fig. 1 is a cross-sectional view schematically showing a composition for forming a three-dimensional object 100 according to this embodiment.

[0010] The three-dimensional modeling composition 100 is injected by a three-dimensional modeling device or an injection molding device to form a three-dimensional object. As shown in Figure 1, the three-dimensional modeling composition 100 contains inorganic particles 10 at least part of whose surface is modified with a resin 20. Each component will be described below.

[0011] Ingredients 1.1.1. Inorganic particles A plurality of inorganic particles 10 are provided. The number of inorganic particles 10 is not particularly limited. The inorganic particles 10 are made of an inorganic material. The inorganic particles 10 are, for example, metal particles such as stainless steel or iron, or ceramic particles. The inorganic particles 10 may be made of a combination of two or more types of materials. The three-dimensional modeling composition 100 may be made up of a plurality of inorganic particles 10 made of the same material, or may be made up of a plurality of different materials. The melting point of the inorganic particles 10 is equal to or higher than the melting point of the resin 20. The shape of the inorganic particles 10 is, for example, spherical.

[0012] The inorganic particles 10 have an average particle size of, for example, 0.5 μm to 100 μm, preferably 1 μm to 10 μm, and more preferably 2 μm to 5 μm. When the inorganic particles 10 have an average particle size of 0.5 μm or more, it is possible to prevent unwanted irregularities from occurring in a three-dimensional object formed using the three-dimensional forming composition 100. When the inorganic particles 10 have an average particle size of 100 μm or less, it is possible to improve the strength of a three-dimensional object formed using the three-dimensional forming composition 100.

[0013] The average particle size refers to the average particle size on a volume basis, and can be determined, for example, by adding a sample to methanol, dispersing the resultant dispersion for 3 minutes using an ultrasonic disperser, and measuring the dispersion using a Coulter Counter particle size distribution analyzer (TA-II model, manufactured by COULTER ELECTRONICS INS) with a 50 μm aperture.

[0014] Resin Resin 20 is an acrylate-based resin. Resin 20 includes a structural unit derived from an acrylate. Resin 20 may be composed of a structural unit derived from an acrylate. Resin 20 includes, for example, at least one selected from a structural unit derived from 3,3,5-trimethylcyclohexyl acrylate (TMCHA), a structural unit derived from phenoxyethyl acrylate (PEA), and a structural unit derived from dodecyl acrylate (C12A). Resin 20 may be composed of a structural unit derived from TMCA, a structural unit derived from PEA, or a structural unit derived from C12A.

[0015] Resin 20 is not a copolymer resin of acrylate and methacrylate, and does not contain, for example, a structural unit derived from methacrylate.

[0016] The resin 20 modifies at least a portion of the surface of the inorganic particle 10. The resin 20 may modify the entire surface of the inorganic particle 10. The resin 20 is chemically bonded to the inorganic particle 10. This makes it possible to prevent the resin 20 from falling off the inorganic particle 10 when the three-dimensional modeling composition 100 is ejected from a nozzle.

[0017] The resin 20 is bonded to the inorganic particles 10 by introducing a polymerization initiation group onto the surface of the inorganic particles 10. The polymerization initiation group is formed by, for example, reacting the inorganic particles 10 with a silane coupling agent. By this, the resin 20 is introduced onto the surface of the inorganic particle 10. An example of the silane coupling agent is (3-trimethoxysilyl)propyl 2-bromo-2-methylpropionate. Here, Fig. 2 is a diagram schematically showing a method for modifying the surface of the inorganic particle 10 with the resin 20.

[0018] As shown in A of FIG. 2, for example, inorganic particles 10 have hydroxyl groups on their surfaces. As shown in B of FIG. 2, the polymerization initiating groups can be introduced onto the surfaces of the inorganic particles 10 by carrying out a dehydration condensation reaction between the inorganic particles 10 having hydroxyl groups on their surfaces and a silane coupling agent. Then, as shown in C of FIG. 2, the inorganic particles 10 having the polymerization initiating groups introduced therein are polymerized with a monomer that is a constituent unit of the resin 20 to be formed. In the illustrated example, TMCHA is used as the monomer.

[0019] Examples of polymerization reactions include atom transfer radical polymerization (ATRP), nitroxide-mediated radical polymerization (NMP), and reversible addition-fragmentation chain transfer polymerization (RAFT), and ATRP is preferred. By using ATRP, the inorganic particles 10 can be highly densely modified with the resin 20.

[0020] The reaction between the inorganic particles 10 having the polymerization initiator groups introduced therein and the monomers that are the constituent units of the resin 20 is carried out using, for example, a polymerization catalyst. Examples of the polymerization catalyst include copper-based catalysts such as CuBr2. Copper-based catalysts may be used in combination with various ligands, thereby improving catalytic activity. If necessary, a reducing agent may be used in combination to control the valence of the catalyst. Examples of the reducing agent include azobisisobutyronitrile (AIBN).

[0021] In the example shown in FIG. 1 , the resin 20 is configured as a plurality of thread-like members 22. The number of thread-like members 22 is not particularly limited. The length of the thread-like members 22 is, for example, 10 nm or more and 500 nm or less, preferably 20 nm or more and 300 nm or less, and more preferably 30 nm or more and 100 nm or less. The diameter of the thread-like members 22 is, for example, 0.5 nm or more and 10 nm or less, preferably 0.7 nm or more and 5 nm or less, and more preferably 1 nm or more and 3 nm or less. The length and diameter of the thread-like members 22 are measured, for example, by a transmission electron microscope (TEM).

[0022] The shape of the resin 20 is not particularly limited, and although not shown, the resin 20 may be configured as a coating that covers the surface of the inorganic particles 10.

[0023] The weight average molecular weight of the resin 20 is, for example, 10,000 to 500,000, preferably 50,000 to 400,000, and more preferably 100,000 to 300,000. The "weight average molecular weight" refers to the weight average molecular weight in terms of polystyrene measured by gel permeation chromatography (GPC).

[0024] The three-dimensional modeling composition 100 is injected in a state in which the resin 20 is melted by heating. The three-dimensional modeling composition 100 may be injected in a plasticized state. The resin 20 functions as a binder that binds the inorganic particles 10 together in a layer formed by injecting the three-dimensional modeling composition 100, for example.

[0025] The volume ratio of the resin 20 to the inorganic particles 10 is, for example, 3.0 volume % or more and 40.0 volume % or less, preferably 4.0 volume % or more, when the volume of the inorganic particles 10 is taken as 100%. The content is from 35.0% by volume to 35.0% by volume, and more preferably from 7.3% by volume to 30.3% by volume.

[0026] If the volume ratio of the resin 20 to the inorganic particles 10 is 3.0% by volume or more, the inorganic particles 10 can be sufficiently bonded in the layer formed by ejecting the composition 100 for three-dimensional modeling.

[0027] When the volume ratio of the resin 20 to the inorganic particles 10 is 40.0% by volume or less, the heating and debinding time of the composition 100 can be shortened when a three-dimensional object is formed using the composition 100. This can suppress warping, distortion, and cracking of the three-dimensional object, a decrease in dimensional accuracy, and an increase in the residual carbon content. As a result, the productivity of three-dimensional objects can be improved and the environmental impact can be reduced.

[0028] The volume ratio of the resin 20 to the inorganic particles 10 can be determined from the weight of the resin 20 relative to the inorganic particles 10 measured by thermogravimetric analysis (TGA) and the density of the resin 20, for example.

[0029] Although not shown, the three-dimensional printing composition 100 may contain resin particles that are not chemically bonded to the inorganic particles 10. The resin particles are formed, for example, from a monomer for forming the resin 20. However, in consideration of the strength of a three-dimensional object to be printed using the three-dimensional printing composition 100, it is preferable that the three-dimensional printing composition 100 does not contain such resin particles.

[0030] 1.1.3. Flow aids The three-dimensional forming composition 100 may further contain a flow aid 30, as shown in Fig. 3. Fig. 3 is a cross-sectional view schematically showing the three-dimensional forming composition 100 according to this embodiment.

[0031] As shown in Fig. 3, the flow aid 30 fills gaps in the resin 20, for example. The flow aid 30 is provided around the filamentous members 22 that make up the resin 20. The flow aid 30 is an additive that is added to the inorganic particles 10 modified with the resin 20. The flow aid 30 improves the fluidity of the three-dimensional modeling composition 100 when the resin 20 is melted by heating.

[0032] The flow aid 30 includes, for example, a compound having a carboxyl group or an ester group. The flow aid 30 may be composed of a compound having a carboxyl group or an ester group. The compound contained in the flow aid 30 includes, for example, at least one selected from stearic acid (SA) and diisodecyl phthalate (DIDP).

[0033] When the monomer for forming resin 20 is TMCHA, the compound contained in flow aid 30 is preferably stearic acid. Figure 4 is a graph showing the interaction between a TMCHA polymer and a linear saturated fatty acid. The horizontal axis represents the number of carbon atoms in the linear saturated fatty acid. The vertical axis represents the difference Δδ in the solubility parameter (SP value) between the TMCHA polymer and the linear saturated fatty acid.

[0034] 4, it can be seen that the carbon number of the straight-chain saturated fatty acid that has good interaction with the TMCHA polymer is 11 to 20. Therefore, it can be seen that stearic acid, which has 18 carbon atoms, has good interaction with the TMCHA polymer.

[0035] FIG. 5 is a table showing monomers for forming the resin 20 and the range of carbon numbers of linear saturated fatty acids that exhibit good interaction. "C4A" in FIG. 5 represents N-butyl acrylate. .

[0036] The volume ratio of the flow aid 30 to the inorganic particles 10 is, for example, 5.0 volume % or more and 50.0 volume % or less, preferably 7.0 volume % or more and 30.0 volume % or less, more preferably 10.0 volume % or more and 20.0 volume % or less, and even more preferably 11.3 volume % or more and 15.5 volume % or less, when the volume of the inorganic particles 10 is 100%.

[0037] If the volume ratio of the flow aid 30 to the inorganic particles 10 is 5.0% by volume or more, the fluidity of the three-dimensional modeling composition 100 can be improved when the resin 20 is melted by heating. If the volume ratio of the flow aid 30 to the inorganic particles 10 is 50.0% by volume or less, an increase in the residual carbon rate can be suppressed.

[0038] The volume ratio of the flow aid 30 to the inorganic particles 10 can be determined, for example, from the weight of the flow aid 30 relative to the inorganic particles 10 measured by TGA and the density of the flow aid 30. In the composition for three-dimensional modeling 100, the content of the resin 20 may be smaller than the content of the flow aid 30, for example.

[0039] The total content of the resin 20 and the flow aid 30 is, for example, 0.5 parts by mass or more and 10.0 parts by mass or less, and preferably 0.6 parts by mass or more and 6.0 parts by mass or less, relative to 100 parts by mass of the inorganic particles 10. The total content of the resin 20 and the flow aid 30 relative to the inorganic particles 10 can be determined, for example, by TGA.

[0040] Note that the three-dimensional printing composition 100 does not necessarily contain the flow aid 30, as shown in Fig. 1. If the three-dimensional printing composition 100 does not contain the flow aid 30, the strength of the three-dimensional object printed using the three-dimensional printing composition 100 can be improved. However, if it is desired to improve the fluidity of the three-dimensional printing composition 100, it is preferable that the three-dimensional printing composition 100 contains the flow aid 30, as shown in Fig. 3.

[0041] 1.1.4. Adhesives The three-dimensional forming composition 100 may further contain an adhesive 40, as shown in Fig. 6. Fig. 6 is a cross-sectional view schematically showing the three-dimensional forming composition 100 according to this embodiment. For convenience, Fig. 6 shows one inorganic particle 10.

[0042] As shown in FIG. 6 , the adhesive 40 covers the inorganic particles 10 whose surfaces are modified with a resin 20 and whose gaps between the resins 20 are filled with a flow aid 30. The adhesive 40 is not provided in the gaps between the resins 20, for example. The adhesive 40 is an additive that is added to the inorganic particles 10 whose surfaces are modified with a resin 20. The adhesive 40 imparts adhesiveness to the inorganic particles 10 whose surfaces are modified with a resin 20. This can improve the strength of a three-dimensional object formed using the three-dimensional modeling composition 100, for example.

[0043] The adhesive 40 includes, for example, at least one selected from ethylene vinyl acetate copolymer (EVA) and glycerin ester of abietic acid (rosin) (rosin (SE10)).

[0044] 1 and 3, the three-dimensional forming composition 100 may contain an adhesive 40. Although not shown, the three-dimensional forming composition 100 may contain an adhesive 40 without containing the flow aid 30.

[0045] 1.1.5. Other ingredients The composition for three-dimensional modeling 100 includes the inorganic particles 10, the resin 20, the flow aid 30, and the like. In addition to the adhesive 40, the adhesive may contain other components. Examples of the other components include dispersants, surfactants, thickeners, anti-aggregating agents, antifoaming agents, slip agents, colorants such as pigments and dyes, penetration enhancers, humectants, antifungal agents, preservatives, antioxidants, UV absorbers, chelating agents, pH adjusters, and solvents as volatile components. One or more selected from these may be used in combination. However, the content of the other components is preferably 5.0% by mass or less.

[0046] 1.2. Physical properties etc. The glass transition temperature of the three-dimensional modeling composition 100 is 8.6°C or higher and 71.3°C or lower, preferably 21.8°C or higher and 65.0°C or lower, more preferably 25.8°C or higher and 60.0°C or lower, and even more preferably 43.7°C or higher and 50.7°C or lower. For example, if the glass transition temperature Tg of the three-dimensional modeling composition 100 is 25.0°C or higher, the shape retention of a three-dimensional object modeled using the three-dimensional modeling composition 100 can be improved. The glass transition temperature can be determined, for example, from tan δ measured using a rheometer.

[0047] The complex viscosity of the composition for three-dimensional modeling 100 at 150°C is, for example, 1.00 × 10 4 Pa·s or more 3.00×10 6 Pa·s or less, preferably 2.89×10 5 Pa·s or less, and more preferably 2.39×10 5 Pa·s or less, and even more preferably 1.00×10 5 The complex viscosity of the composition for three-dimensional modeling 100 is 3.00×10 Pa·s or less. 6 If the viscosity is Pa·s or less, when the resin 20 is melted by heating, the composition 100 for forming a three-dimensional object can be easily injected.

[0048] In the composition for three-dimensional formation 100, the inorganic particles 10 modified with the resin 20 may be gathered together to form a mass of several centimeters, or may be in the form of powder.

[0049] The three-dimensional modeling composition 100 is injected from a nozzle with a nozzle diameter of 2.5 mm while at least a part of the resin 20 is in a melted state.

[0050] 1.3. Effects The three-dimensional modeling composition 100 is a three-dimensional modeling composition injected by a three-dimensional modeling device or an injection molding device, and includes inorganic particles 10 at least partially modified on the surface with a resin 20. The resin 20 is an acrylate-based resin, not a copolymer resin of acrylate and methacrylate, and has a glass transition temperature of 8.6°C or higher and 71.3°C or lower. Therefore, the three-dimensional modeling composition 100 can be smoothly injected from a nozzle, as shown in the "Examples and Comparative Examples" described below. Furthermore, even with a small amount of resin 20 functioning as a binder, friction between the inorganic particles 10 can be reduced, and thus the composition can be smoothly injected from a nozzle even with a small amount of binder.

[0051] The glass transition temperature of the three-dimensional modeling composition 100 may be 21.8° C. or higher, or 43.7° C. or higher. Therefore, the three-dimensional modeling composition 100 can improve the shape retention of a three-dimensional object modeled using the three-dimensional modeling composition 100.

[0052] In the three-dimensional forming composition 100, the volume ratio of the resin 20 to the inorganic particles 10 may be 7.3 volume % or more and 30.3 volume % or less. Therefore, the three-dimensional forming composition 100 can be suitably ejected from a nozzle while reducing the amount of the resin 20.

[0053] In the three-dimensional printing composition 100, the resin 20 may contain at least one selected from a structural unit derived from 3,3,5-trimethylcyclohexyl acrylate, a structural unit derived from phenoxyethyl acrylate, and a structural unit derived from dodecyl acrylate. Therefore, in the three-dimensional printing composition 100, As shown, the nozzle ejects well.

[0054] The three-dimensional printing composition 100 may contain a compound having a carboxyl group or an ester group, which can improve the fluidity of the three-dimensional printing composition 100 when the resin 20 is melted by heating.

[0055] In the three-dimensional forming composition 100, the content of the resin 20 may be smaller than the content of the compound contained in the flow aid 30. Therefore, in the three-dimensional forming composition 100, the amount of the resin 20 can be reduced.

[0056] The three-dimensional modeling composition 100 may be injected from a nozzle with a nozzle diameter of 2.5 mm while at least a portion of the resin 20 is melted. The three-dimensional modeling composition 100 can be successfully injected from a nozzle with such a diameter because the resin 20 is an acrylate resin, not a copolymer resin of acrylate and methacrylate, and has a glass transition temperature of 8.6°C or higher and 71.3°C or lower.

[0057] 2. Three-dimensional printing equipment Next, a three-dimensional modeling apparatus using the composition 100 for three-dimensional modeling according to this embodiment will be described with reference to the drawings. Fig. 7 is a cross-sectional view schematically showing a three-dimensional modeling apparatus 200 using the composition 100 for three-dimensional modeling according to this embodiment.

[0058] 7, the three-dimensional modeling apparatus 200 includes, for example, a material supply unit 210, a flat screw 220, a motor 230, a barrel 240, a heater 250, a nozzle 260, a stage 270, and a position change unit 280. The three-dimensional modeling apparatus 200 is, for example, a fused deposition modeling (FDM (registered trademark)) type three-dimensional modeling apparatus.

[0059] The material supply unit 210 is supplied with, for example, the above-described three-dimensional modeling composition 100. The three-dimensional modeling device 200 uses the three-dimensional modeling composition 100 as a raw material. The three-dimensional modeling composition 100 is introduced from the material supply unit 210 into a spiral groove 222 formed in a flat screw 220. The spiral groove 222 is formed on the surface of the flat screw 220 facing the barrel 240. While being rotated by a motor 230, the flat screw 220 transports the three-dimensional modeling composition 100 to a communication hole 242 formed in the center of the barrel 240.

[0060] The three-dimensional modeling composition 100 is heated by the heater 250 while passing through the spiral groove 222. This causes the resin 20 of the three-dimensional modeling composition 100 to melt. Melting is a concept that includes plasticization. The plasticized three-dimensional modeling composition 100 then passes through the communication hole 242 and the nozzle hole 262 and is injected from the nozzle 260 onto the stage 270.

[0061] The three-dimensional modeling device 200 drives the position changing unit 280 to change the relative position between the nozzle 260 and the stage 270 while injecting the three-dimensional modeling composition 100 from the nozzle 260 onto the stage 270 .

[0062] As a result, the three-dimensional printing apparatus 200 forms a laminate 102 of a predetermined shape made up of multiple layers on the stage 270. The laminate 102 is made of the composition 100 for three-dimensional printing. In the laminate 102, the resin 20 contained in the composition 100 for three-dimensional printing functions as a binder that binds the inorganic particles 10 together. Then, by degreasing and sintering the laminate 102, part or all of the resin 20 is removed, and the three-dimensional printing is completed. Things are formed.

[0063] The three-dimensional modeling composition according to the present embodiment is not limited to use in a three-dimensional modeling apparatus, and may be used in an injection molding apparatus (not shown). In this case, the three-dimensional modeling composition is injected from the nozzle of the injection molding apparatus into a cavity defined by a mold, with the resin in a molten state.

[0064] 3. Examples and Comparative Examples 3.1. Sample preparation Example 1 A mixture of 1000 g of SUS particles made of SUS (Steel Use Stainless) 630 with an average particle size of 4.0 μm and 327.5 g of hexane as a polymerization initiator reaction solvent was subjected to ultrasonic treatment for 30 minutes.

[0065] Next, 5 g of (3-trimethoxysilyl)propyl 2-bromo-2-methylpropionate was added as a polymerization initiator silane coupling agent, and a set of ultrasonic treatment for 30 minutes and manual shaking dispersion treatment for 5 minutes was carried out three times.

[0066] Next, the hexane was removed by heat treatment at 110°C for 2 hours in a vacuum, and the hydroxyl groups on the surface of the SUS particles were bonded to the polymerization initiation groups through a dehydration condensation reaction.

[0067] Thereafter, the silane coupling agent with no unbound polymerization initiator groups was removed by washing with hexane, and the hexane was removed by decantation. After that, the hexane was removed by vacuum drying at 50°C, and the polymerization initiator group-modified SUS particles were obtained.

[0068] Meanwhile, 1.40 g of CuBr2, 6.30 g of CuCl, 13.8 g of N,N,N',N'',N''-pentamethyldiethylenetriamine (PMDETA), and 400 g of pure water were weighed out and mixed and stirred under a N2 gas atmosphere to prepare a catalyst solution.

[0069] Next, 200 g of the polymerization initiating group-modified SUS particles, 200 g of TMCHA, and 300 g of isopropanol were mixed and stirred under an N2 gas atmosphere.

[0070] The catalyst solution prepared as described above was added to the mixture, and stirring was started under a N2 gas atmosphere at 25°C. After stirring for a total of 10 hours, a dispersion of SUS particles whose surfaces were modified with a resin composed of structural units derived from TMCHA was obtained.

[0071] The solvent and catalyst solution were then removed from the dispersion of resin-modified SUS particles, and the particles were washed 10 times with 150 mL of tetrahydrofuran. After the tetrahydrofuran was removed, the resin-modified SUS particles were dried by evaporating the tetrahydrofuran at 80°C while flowing N2 gas.

[0072] As described above, the composition for three-dimensional modeling of Example 1 was prepared. Fig. 8 is a table showing the preparation conditions for Example 1, as well as for Examples 2 to 6 and Comparative Examples 1 to 3 described below. In Fig. 8, the column "Resin (A)" lists the monomers for forming the resin.

[0073] Example 2 In Example 2, resin-modified SUS particles were prepared in the same manner as in Example 1, and then a solution of 2.76 g of stearic acid dissolved in 107.43 g of tetrahydrofuran was added to 150.01 g of the resin-surface-modified SUS particles, and the mixture was mixed manually at room temperature for 15 minutes. After evaporating most of the tetrahydrofuran with a N2 gas flow, the mixture was mixed with a N2 gas flow. Tetrahydrofuran was evaporated to dryness under reduced pressure at 80° C. for 2 hours.

[0074] In this way, a composition for three-dimensional modeling of Example 2 was prepared.

[0075] Example 3 In Example 3, a composition for forming a three-dimensional object was prepared in the same manner as in Example 2, except that PEA was used instead of TMCHA and DIDP was used instead of stearic acid.

[0076] Example 4 In Example 4, a composition for forming a three-dimensional object was prepared in the same manner as in Example 2, except that a mixture of EVA, rosin (SE10), and stearic acid was used instead of stearic acid.

[0077] Example 5 In Example 5, a composition for forming a three-dimensional object was prepared in the same manner as in Example 1, except that C12A was used instead of TMCHA.

[0078] Example 6 In Example 6, a composition for forming a three-dimensional object was prepared in the same manner as in Example 1, except that PEA was used instead of TMCHA.

[0079] 3.1.7. Comparative Example 1 In Comparative Example 1, a composition for three-dimensional modeling was prepared in the same manner as in Example 1, except that benzyl methacrylate (BzMA) was used instead of TMCHA and the mass ratio of SUS particles to monomer was SUS particles:monomer = 1:0.069.

[0080] 3.1.8. Comparative Example 2 In Comparative Example 2, a composition for three-dimensional modeling was prepared in the same manner as in Example 2, except that BzMA was used instead of TMCHA, DIDP was used instead of stearic acid, and the weight ratio of SUS particles to monomer was SUS particles:monomer = 1:0.069.

[0081] 3.1.9. Comparative Example 3 In Comparative Example 3, a mixture of N-butyl methacrylate (C4MA) and N-butyl acrylate (C4A) was used instead of TMCHA, and the mass ratio of the SUS particles to the monomer was SUS particles:monomer = 1:0.11. Except for this, a composition for three-dimensional modeling was prepared in the same manner as in Example 1. The mass ratio of the C4MA to the C4A was C4MA:C4A = 7:3.

[0082] In the above-mentioned method for producing a composition for three-dimensional modeling, the SUS particles made of SUS630 were manufactured by Epson Atomic Corporation. Hexane, isopropanol, and tetrahydrofuran were manufactured by Kanto Chemical Co., Ltd. The silane coupling agent was manufactured by Gelest. CuBr2, CuCl, and pure water were manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. PMDETA, TMCHA, stearic acid, PEA, DIDP, BzMA, C4MA, and C4A were manufactured by Tokyo Chemical Industry Co., Ltd. EVA was manufactured by Sigma-Aldrich. Rosin (SE10) was manufactured by Harima Chemicals Co., Ltd.

[0083] The chemical formulae of the monomers TMCHA, PEA, C12A, BzMA, C4MA, and C4A are as follows:

[0084] [ka]

[0085] The chemical formulas of the additives used, stearic acid (SA), DIDP, EVA, and rosin (SE10), are as follows:

[0086] [ka]

[0087] Experimental Method 3.2.1. Content The resin and additive contents in the three-dimensional modeling composition were measured by TGA. A TGA model "TG8121" manufactured by Rigaku Corporation was used. Specifically, as shown in FIG. 8, the total parts by mass of the resin and additives was calculated when the mass of the SUS particles was taken as 100 parts by mass. Furthermore, the ratio of parts by mass of the resin to the additives was calculated.

[0088] Furthermore, the volume ratio of the resin and additives to the SUS particles was calculated in volume %, assuming that the volume of the SUS particles was 100%. As an example, the volume ratio of the resin to the SUS particles in Example 1 is explained below.

[0089] The diameter of the SUS particle is 4 μm, so if the shape of the SUS particle is assumed to be spherical, the volume of one SUS particle is 3.35 × 10 -11 cm 3 The density of SUS particles is 7.78 g / cm 3 Therefore, multiplying the volume of one SUS particle by the density, the mass of one SUS particle is 2.61 x 10 -10 g.

[0090] From TGA, the resin content per 100 parts by mass of SUS particles was 0.6 parts by mass. Therefore, by multiplying the mass of one SUS particle by 0.006, the mass of the resin was calculated as 1.56 × 10 -12 g. The density of the resin is 1.18 g / cm 3Then, the volume of the resin is 1.33 × 10 -12 cm 3 Then, by dividing the volume of the resin by the volume of the SUS particles, the volume ratio of the resin to the SUS particles can be calculated as 4.0% by volume, assuming that the volume of the SUS particles is 100%.

[0091] The density of the resin is 1.18 g / cm regardless of the type. 3 The density of SA was 0.941 g / cm 3 The density of DIDP is 0.968 g / cm 3 The density of EVA is 0.941 g / cm 3 The density of rosin (SE10) was 1.07 g / cm 3 It was decided.

[0092] Furthermore, the content ratio of the resin and the additive was calculated in volume % when the total volume of the SUS particles, the resin, and the additive was taken as 100%.

[0093] 3.2.2. Glass transition temperature and complex viscosity The glass transition temperature (Tg) and complex viscosity of the three-dimensional modeling composition were measured using an Anton Paar MCR302 rheometer at a frequency of 1 Hz. The glass transition temperature (Tg) was determined from the peak temperature in the temperature dependence of tan δ. The complex viscosity was measured at 150°C.

[0094] In Example 5, Tg was relatively low, making it difficult to measure tan δ. Therefore, the creep temperature measured at the same time was used instead to estimate Tg. A correlation between Tg and creep temperature has been confirmed.

[0095] 3.2.3. Injection characteristics The injection properties of the three-dimensional modeling composition were evaluated using a hand truder manufactured by Toyo Seiki Seisakusho, Ltd. Specifically, the three-dimensional modeling composition was placed in the cylinder of the hand truder, and while applying a force of approximately 20 MPa to the three-dimensional modeling composition, the temperature was gradually increased and the three-dimensional modeling composition was injected from a nozzle with a diameter of 2.5 mm (nozzle land length of 5.0 mm). However, if the injection temperature is raised too high, the three-dimensional modeling composition will decompose. The injection properties were evaluated based on stick-slip noise. Specific evaluation criteria for the injection properties are as follows:

[0096] A: Injection without stick-slip noise B: Injection with a small stick-slip sound C: Injection with loud stick-slip noise D: Not injected at all

[0097] Experimental Results FIG. 8 shows the experimental results of Examples 1 to 6 and Comparative Examples 1 to 3.

[0098] As shown in Fig. 8, in Examples 1 to 6, which used acrylate resins, the three-dimensional modeling compositions could be injected from the nozzle of the hand truder. On the other hand, in Comparative Examples 1 and 2, which used methacrylate resins, the three-dimensional modeling compositions could not be injected at all, even when the injection temperature was increased to 225°C. In Comparative Example 3, which used a copolymer resin of acrylate and methacrylate, the three-dimensional modeling compositions could not be injected at all.

[0099] Therefore, it was found that by using an acrylate resin that is not a copolymer resin of acrylate and methacrylate, the composition for three-dimensional modeling can be ejected well from the nozzle.

[0100] In Example 1, the resin content was very small (0.6 parts by mass) when the SUS particles were used as 100 parts by mass, but the composition for three-dimensional modeling could be injected. In Comparative Example 3, the resin content was large (5.0 parts by mass) when the SUS particles were used as 100 parts by mass, but the composition for three-dimensional modeling could not be injected.

[0101] Therefore, it was found that by using an acrylate-based resin that is not a copolymer resin of acrylate and methacrylate, the three-dimensional modeling composition can be ejected well from the nozzle even if the resin content is small.

[0102] Comparative Examples 1 and 2, which used methacrylate as the monomer, had higher complex viscosities than Examples 1 to 6, which used acrylate as the monomer. Methacrylate has steric distortion energy that is about 1.5 times that of acrylate, which can be said to be disadvantageous in terms of expressing fluidity.

[0103] Examples 2 and 3, which contained SA and DIDP, had lower complex viscosities than the other examples and comparative examples. Example 2, in particular, had a high Tg of 50.7°C and could be injected without stick-slip noise, making it an excellent composition for three-dimensional modeling. It was found that TMCHA and SA have good compatibility in terms of injection properties.

[0104] The above-described embodiment and modifications are merely examples, and the present invention is not limited to these. For example, the embodiments and modifications can be combined as appropriate.

[0105] The present invention includes configurations that are substantially the same as the configurations described in the embodiments, for example, configurations with the same functions, methods, and results, or configurations with the same purpose and effects. The present invention also includes configurations that replace non-essential parts of the configurations described in the embodiments. The present invention also includes configurations that achieve the same effects or purposes as the configurations described in the embodiments. The present invention also includes configurations that add publicly known technology to the configurations described in the embodiments.

[0106] The following can be derived from the above-described embodiment and modifications.

[0107] One embodiment of the composition for three-dimensional modeling is A composition for three-dimensional modeling that is injected by a three-dimensional modeling device or an injection molding device, The inorganic particles have at least a portion of their surfaces modified with a resin; The resin is an acrylate-based resin, not a copolymer resin of acrylate and methacrylate, The glass transition temperature is 8.6°C or higher and 71.3°C or lower.

[0108] Such a composition for three-dimensional modeling can be ejected well from a nozzle.

[0109] In one embodiment of the composition for three-dimensional formation, The glass transition temperature may be 21.8°C or higher.

[0110] Such a composition for forming a three-dimensional object can improve the shape retention of a model formed using the composition for forming a three-dimensional object.

[0111] In one embodiment of the composition for three-dimensional formation, The glass transition temperature may be 43.7°C or higher.

[0112] Such a composition for forming a three-dimensional object can improve the shape retention of a model formed using the composition for forming a three-dimensional object.

[0113] In one embodiment of the composition for three-dimensional formation, The volume ratio of the resin to the inorganic particles may be 7.3% by volume or more and 30.3% by volume or less.

[0114] Such a composition for three-dimensional modeling can be suitably ejected from a nozzle while reducing the amount of resin used.

[0115] In one embodiment of the composition for three-dimensional formation, The resin may contain at least one selected from a structural unit derived from 3,3,5-trimethylcyclohexyl acrylate, a structural unit derived from phenoxyethyl acrylate, and a structural unit derived from dodecyl acrylate.

[0116] Such a composition for three-dimensional modeling can be ejected well from a nozzle.

[0117] In one embodiment of the composition for three-dimensional formation, It may contain a compound having a carboxyl group or an ester group.

[0118] Such a composition for forming a three-dimensional object can improve the flowability.

[0119] In one embodiment of the composition for three-dimensional formation, The content of the resin may be smaller than the content of the compound.

[0120] Such a composition for three-dimensional modeling can reduce the amount of resin. [Explanation of symbols]

[0121] 10...inorganic particles, 20...resin, 22...filamentous member, 30...flow aid, 40...adhesive, 100...composition for three-dimensional modeling, 102...laminate, 200...three-dimensional modeling device, 210...material supply unit, 220...flat screw, 222...spiral groove, 230...motor, 240...barrel, 250...heater, 260...nozzle, 270...stage, 280...position change unit

Claims

1. A composition for three-dimensional modeling that is injected by a three-dimensional modeling device or an injection molding device, The inorganic particles have at least a portion of their surfaces modified with a resin; The resin is an acrylate-based resin, not a copolymer resin of acrylate and methacrylate, A composition for three-dimensional modeling, having a glass transition temperature of 8.6°C or higher and 71.3°C or lower.

2. In claim 1, The composition for three-dimensional modeling, wherein the glass transition temperature is 21.8°C or higher.

3. In claim 1, The composition for three-dimensional modeling, wherein the glass transition temperature is 43.7°C or higher.

4. In claim 1, A three-dimensional modeling composition, wherein a volume ratio of the resin to the inorganic particles is 7.3 volume % or more and 30.3 volume % or less.

5. In claim 1, The resin is a three-dimensional modeling composition, and includes at least one selected from a structural unit derived from 3,3,5-trimethylcyclohexyl acrylate, a structural unit derived from phenoxyethyl acrylate, and a structural unit derived from dodecyl acrylate.

6. In claim 1, A composition for three-dimensional modeling, comprising a compound having a carboxyl group or an ester group.

7. In claim 6, The composition for three-dimensional modeling, wherein the content of the resin is smaller than the content of the compound.

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