Molding die, and composition for three-dimensional modeling

Abstract

To provide a molding die for injection molding, which has an excellent strength and effectively prevents inorganic particles from falling off, and to provide a composition for three-dimensional modeling, which can be suitably used for producing a modeled object that has an excellent strength, effectively prevents inorganic particles from falling off.SOLUTION: A molding die of the present invention is a molding die for use in injection molding, which has a laminated structure in which a plurality of layers are laminated, wherein the molding die is made of a material containing inorganic particles surface-modified with a silane coupling agent and a thermoplastic resin, and a bending stress measured by a three-point bending strength test is 120 MPa or more. An elastic modulus of the molding die as determined by a three-point bending strength test is preferably 8300 MPa or more.SELECTED DRAWING: None

Description

[Technical Field]

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

[0002] 2. Description of the Related Art Injection molding apparatuses are known that supply a material plasticized by a plasticizing device into a cavity provided in a mold to form a molded product.

[0003] For example, Patent Document 1 describes the use of a three-dimensional modeling machine to create a mold for an injection molding machine. The three-dimensional modeling machine makes it possible to create shapes that could not be created conventionally in an integrated manner.

[0004] One example of a method for manufacturing a model using a three-dimensional modeling machine is fused deposition molding (FDM; "FDM" is a registered trademark), in which a three-dimensional modeling composition containing inorganic particles such as metal particles and a thermoplastic resin is ejected in a plasticized state to form a layer.

[0005] Furthermore, in a composition for three-dimensional modeling, a silane coupling agent is added to improve the compatibility between inorganic particles and resin (see, for example, Patent Document 2). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-124593 [Patent Document 2] Japanese Patent Application Laid-Open No. 2016-112793 Summary of the Invention [Problem to be solved by the invention]

[0007] However, conventionally, it has not been possible to make the strength of a molding die manufactured by a three-dimensional molding method sufficiently high.

[0008] For example, the pressure during injection molding can reach 100 MPa to 200 MPa, which can cause damage to the fine structures and thin-walled portions of the mold during injection molding. [Means for solving the problem]

[0009] The present invention has been made to solve the above-mentioned problems, and can be realized as the following application examples.

[0010] A molding die according to an application example of the present invention is a molding die used for injection molding, It has a laminated structure in which a plurality of layers are laminated, The material is made of a material containing inorganic particles surface-modified with a silane coupling agent and a thermoplastic resin, The bending stress measured by a three-point bending strength test is 120 MPa or more.

[0011] Furthermore, a composition for three-dimensional modeling according to an application example of the present invention includes inorganic particles surface-modified with a silane coupling agent and a thermoplastic resin, The content of the silane coupling agent relative to the unit surface area of ​​the inorganic particles is 0.00233 g / m 2 More than 0.00933g / m 2 The following is the result. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a cross-sectional view showing a schematic configuration example of an injection molding apparatus in which the molding die of the present invention is used. [Figure 2] FIG. 2 is a perspective view schematically showing a flat screw of an injection molding machine. [Figure 3] FIG. 3 is a diagram schematically illustrating the barrel of an injection molding device. [Figure 4] FIG. 4 is an exploded perspective view showing a typical example of the configuration of a molding die of an injection molding machine. [Figure 5] FIG. 5 is a perspective view schematically showing a laminate of a molding die. [Figure 6] FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. 5, which schematically shows the laminate of the forming mold. [Figure 7] FIG. 7 is a flowchart illustrating the method for manufacturing the molding die. [Figure 8] FIG. 8 is a diagram schematically illustrating an example of the configuration of a three-dimensional modeling apparatus used to manufacture a molding die. [Figure 9] FIG. 9 is a cross-sectional view schematically showing the modeling unit. [Figure 10] FIG. 10 is a cross-sectional view schematically showing a manufacturing process of a laminate in a three-dimensional modeling apparatus. [Figure 11] FIG. 11 is a table showing the evaluation results of the compositions for three-dimensional modeling of the examples and comparative examples, along with their compositions. [Figure 12] Figure 12 shows the results of measurements taken with a VHV (digital microscope) and image processing using ImageJ (image processing) of strands ejected using the three-dimensional modeling composition of Example 1, which contains KBP-90 manufactured by Shin-Etsu Chemical Co., Ltd. as a silane coupling agent. [Figure 13] Figure 13 shows image processing results of measurements taken with a VHV (digital microscope) of strands ejected using the three-dimensional modeling composition of Example 2, which contains KBM-803 manufactured by Shin-Etsu Chemical Co., Ltd. as a silane coupling agent, using ImageJ (image processing). DETAILED DESCRIPTION OF THE INVENTION

[0013] Preferred embodiments of the present invention will be described in detail below. [1] Molding mold First, the molding die of the present invention will be described.

[0014] The mold of the present invention is a mold used for injection molding, has a laminated structure in which multiple layers are stacked, is made of a material containing inorganic particles surface-modified with a silane coupling agent and a thermoplastic resin, and has a bending stress of 120 MPa or more in a three-point bending strength test.

[0015] By satisfying these conditions, it is possible to provide a mold for injection molding that has excellent strength and effectively prevents inorganic particles from falling off. By using such a mold, damage to the mold during injection molding can be effectively prevented. Furthermore, for example, when cutting the mold as a shaped object obtained by a three-dimensional modeling method to adjust its shape, it is possible to effectively prevent inorganic particles from unintentionally falling off from the surface of the mold. As a result, the dimensional accuracy of the mold can be improved.

[0016] More specifically, by ensuring that the bending stress of the molding die is within the above range, the molding die has a sufficiently high mechanical strength, and breakage during injection molding, particularly breakage in fine structures or thin-walled portions, can be suppressed. In particular, by surface-modifying the inorganic particles with a silane coupling agent, the adhesion between the inorganic particles and the thermoplastic resin is enhanced, and the mechanical strength of the molding die can be improved and the inorganic particles can be suppressed from falling off from the surface of the molding die.

[0017] In the present invention, the bending stress of a forming mold refers to a value measured by a three-point bending test using a three-point bending test jig in accordance with the method described in JIS K7171:2016, on a test piece cut out to a predetermined size from the target forming mold, particularly from a portion having a laminated structure in which multiple layers are stacked as described above.

[0018] On the other hand, if the above conditions are not met, the above excellent effects cannot be obtained.

[0019] For example, if the inorganic particles are not surface-modified with a silane coupling agent, the adhesion to the thermoplastic resin cannot be sufficiently high, the mechanical strength of the molding die cannot be sufficiently high, and, for example, when a molded object obtained by a three-dimensional modeling method is cut to produce the molding die, the inorganic particles cannot be sufficiently prevented from falling off from the surface of the molding die.

[0020] If the bending stress of the molding die is less than the lower limit, the mechanical strength of the molding die cannot be made sufficiently high, and breakage during injection molding cannot be sufficiently prevented.

[0021] As described above, the bending stress of the molding die of the present invention may be 120 MPa or more, preferably 140 MPa or more, and more preferably 150 MPa or more. This makes it possible to make the above-mentioned effects of the present invention more pronounced.

[0022] The mold of the present invention preferably has a modulus of elasticity measured by a three-point bending strength test of 8,300 MPa or more, more preferably 8,400 MPa or more, and even more preferably 8,500 MPa or more. The upper limit of the modulus of elasticity measured by a three-point bending strength test of the mold of the present invention is not particularly limited, but may be 8,600 MPa or less. This makes it possible to improve the mechanical strength, particularly the rigidity, of the molding die.

[0023] In the present invention, the elastic modulus of the molding die can be a value measured by a three-point bending test using a three-point bending test jig in accordance with the method described in JIS K7171: 2016, using a test piece cut out to a predetermined size from the molding die. Alternatively, at least a portion of an injection-molded product may be used instead of the test piece.

[0024] [1-1] Injection molding equipment [1-1-1] Overall structure An injection molding apparatus in which the mold of the present invention is used will be described with reference to the drawings. Fig. 1 is a cross-sectional view showing a schematic configuration example of an injection molding apparatus in which the mold of the present invention is used, in which an X-axis, a Y-axis, and a Z-axis are shown as three mutually orthogonal axes.

[0025] As shown in FIG. 1, the injection molding apparatus 100 includes, for example, a plasticizing device 10, an injection mechanism 20, a nozzle 30, a molding die 40, and a mold clamping device 50.

[0026] The plasticizer 10 is configured to plasticize the supplied material, generate a flowable, paste-like plasticized material, and guide it to the injection mechanism 20.

[0027] In this specification, "plasticization" is a concept that includes melting and refers to changing from a solid to a fluid state. Specifically, in the case of a material that undergoes glass transition, plasticization refers to raising the temperature of the material to or above the glass transition point. In the case of a material that does not undergo glass transition, plasticization refers to raising the temperature of the material to or above the melting point.

[0028] The material supplied to the plasticizing device 10 is, for example, a resin. More specifically, examples of the material include ABS resin, polypropylene, polyethylene, polyacetal, polyvinyl chloride, polyamide, polylactic acid, polycarbonate, modified polyphenylene ether, polybutylene terephthalate, polyethylene terephthalate, polysulfone, polyethersulfone, polyarylate, polyimide, polyamideimide, and polyetherimide. The melting point of the material supplied to the plasticizing device 10 is lower than the melting point of the material constituting the molding die 40.

[0029] The plasticizing device 10 includes, for example, a screw case 12, a drive motor 14, a flat screw 110, a barrel 120, and a heater 130.

[0030] The screw case 12 is a housing that houses the flat screw 110. The flat screw 110 is housed in a space surrounded by the screw case 12 and the barrel 120.

[0031] The drive motor 14 is provided in the screw case 12. The drive motor 14 rotates the flat screw 110.

[0032] The flat screw 110 has a generally cylindrical shape whose size in the direction of the rotation axis RA is smaller than its size in the direction perpendicular to the direction of the rotation axis RA. In the illustrated example, the rotation axis RA is parallel to the Y-axis. The flat screw 110 rotates about the rotation axis RA due to the torque generated by the drive motor 14. The flat screw 110 has a main surface 111, a groove-forming surface 112 opposite the main surface 111, and a connecting surface 113 connecting the main surface 111 and the groove-forming surface 112.

[0033] Here, Fig. 2 is a perspective view that schematically shows the flat screw 110 of the injection molding apparatus 100. For convenience, Fig. 2 shows a state in which the up-down positional relationship is reversed from the state shown in Fig. 1. Also, Fig. 2 shows a simplified illustration of the flat screw 110.

[0034] As shown in FIG. 2 , a first groove 114 is formed in the groove forming surface 112 of the flat screw 110. The first groove 114 has, for example, a central portion 115, a connecting portion 116, and a material introduction portion 117. The central portion 115 faces a communication hole 126 formed in the barrel 120. The central portion 115 communicates with the communication hole 126. The connecting portion 116 connects the central portion 115 and the material introduction portion 117. In the example shown, the connecting portion 116 is formed in a spiral shape from the central portion 115 toward the outer periphery of the groove forming surface 112. The material introduction portion 117 is provided on the outer periphery of the groove forming surface 112. That is, the material introduction portion 117 is provided on the connecting surface 113. The supplied material is introduced from the material introduction section 117 into the first groove 114, passes through the connection section 116 and the central section 115, and is transported to the communication hole 126 provided in the barrel 120. In the illustrated example, two first grooves 114 are provided.

[0035] There is no particular limitation on the number of first grooves 114. Three or more first grooves 114 may be provided, or only one first groove 114 may be provided.

[0036] As shown in Fig. 1, the barrel 120 is disposed opposite the flat screw 110. The barrel 120 has an opposing surface 122 that faces the groove forming surface 112 of the flat screw 110. A communication hole 126 is provided at the center of the opposing surface 122. Fig. 3 is a diagram schematically showing the barrel 120 of the injection molding apparatus 100. For convenience, the barrel 120 is illustrated in a simplified form in Fig. 1.

[0037] As shown in FIG. 3 , second grooves 124 and communication holes 126 are provided on the opposing surface 122 of the barrel 120. A plurality of second grooves 124 are provided. In the illustrated example, six second grooves 124 are provided, but the number is not particularly limited. The plurality of second grooves 124 are provided around the communication holes 126 when viewed from the Y-axis direction. One end of each second groove 124 is connected to the communication holes 126, and the second grooves 124 extend in a spiral shape from the communication holes 126 toward the outer periphery of the opposing surface 122. The second grooves 124 have the function of guiding the plasticized material to the communication holes 126.

[0038] The shape of the second groove 124 is not particularly limited, and may be, for example, linear. One end of the second groove 124 does not have to be connected to the communicating hole 126. Furthermore, the second groove 124 does not have to be provided on the opposing surface 122. However, in consideration of efficiently guiding the plasticized material to the communicating hole 126, it is preferable that the second groove 124 be provided on the opposing surface 122.

[0039] The heater 130 is provided in the barrel 120. In the illustrated example, the heater 130 is configured by four rod heaters provided in the barrel 120. The heater 130 heats the material supplied between the flat screw 110 and the barrel 120. The plasticizing device 10 heats the material while transporting it toward the communicating hole 126 using the flat screw 110, the barrel 120, and the heater 130 to generate a plasticized material, and the generated plasticized material flows out from the communicating hole 126 to the injection mechanism 20.

[0040] 1, the injection mechanism 20 has, for example, a cylinder 22, a plunger 24, and a plunger driver 26. The cylinder 22 is a substantially cylindrical member connected to the communication hole 126. The plunger 24 moves inside the cylinder 22. The plunger 24 is driven by the plunger driver 26, which is composed of a motor, gears, etc.

[0041] The injection mechanism 20 performs metering and injection operations by sliding the plunger 24 within the cylinder 22. The metering operation refers to the operation of guiding the plasticized material located in the communication hole 126 into the cylinder 22 and measuring it within the cylinder 22 by moving the plunger 24 in the -X axis direction away from the communication hole 126. The injection operation refers to the operation of injecting the plasticized material in the cylinder 22 into the molding die 40 via the nozzle 30 by moving the plunger 24 in the +X axis direction approaching the communication hole 126.

[0042] Nozzle 30 is provided with a nozzle hole 32 that communicates with communication hole 126. Nozzle hole 32 injects the plasticized material supplied from plasticizer 10 into mold 40. Specifically, by performing the above-described metering operation and injection operation, the plasticized material measured in cylinder 22 is sent from injection mechanism 20 to nozzle hole 32 via communication hole 126. The plasticized material is then injected from nozzle hole 32 into mold 40.

[0043] The molding die 40 has a movable die 41 and a fixed die 42. The movable die 41 and the fixed die 42 are arranged opposite each other. The molding die 40 has a cavity 140 between the movable die 41 and the fixed die 42 that corresponds to the shape of the molded product. At least one of the movable die 41 and the fixed die 42 has irregularities that define the cavity 140. The plasticized material that flows out from the communication hole 126 is pressure-fed by the injection mechanism 20 and injected into the cavity 140 from the nozzle 30. The movable die 41 and the fixed die 42 will be described in detail below.

[0044] Clamping device 50 has a mold drive unit 52 and has the function of opening and closing movable mold 41 and fixed mold 42. Clamping device 50 drives mold drive unit 52, which is made up of a motor, to rotate ball screw 54, which moves movable mold 41, which is connected to ball screw 54, relative to fixed mold 42, thereby opening and closing molding mold 40. Fixed mold 42 is stationary in injection molding apparatus 100, and movable mold 41 moves relative to stationary fixed mold 42, thereby opening and closing molding mold 40.

[0045] The movable mold 41 is provided with an ejection mechanism 43 for releasing the molded product from the molding mold 40. The ejection mechanism 43 has an ejector pin 44, a support plate 45, a support rod 46, a spring 47, an ejection plate 48, and a thrust bearing 49.

[0046] The ejector pin 44 is a rod-shaped member for ejecting the molded product formed in the cavity 140. The ejector pin 44 is provided to penetrate the movable mold 41 and into the cavity 140. The support plate 45 is a plate member that supports the ejector pin 44. The ejector pin 44 is fixed to the support plate 45. The support rod 46 is fixed to the support plate 45 and inserted into a through-hole provided in the movable mold 41. The spring 47 is disposed in the space between the movable mold 41 and the support plate 45 and is inserted into the support rod 46. During molding, the spring 47 biases the support plate 45 so that the head of the ejector pin 44 forms part of the wall surface of the cavity 140. The ejector plate 48 is fixed to the support plate 45. A thrust bearing 49 is attached to the ejector plate 48. The thrust bearing 49 is provided to prevent the head of the ball screw 54 from damaging the ejector plate 48. Instead of the thrust bearing 49, a thrust sliding bearing or the like may be used.

[0047] [1-1-2] Example of a molding die configuration Fig. 4 is an exploded perspective view schematically showing one configuration example of molding die 40 of injection molding apparatus 100. Fig. 5 is a perspective view schematically showing laminate 142 of molding die 40. Fig. 6 is a cross-sectional view taken along line VI-VI of Fig. 5, schematically showing laminate 142 of molding die 40.

[0048] As shown in Figures 4 to 6, movable die 41 of mold 40 includes a laminate 142 and a matrix 148. In mold 40 shown in Figures 4 to 6, laminate 142 satisfies the conditions for constituent materials and bending stress as described above. For convenience, laminate 142 is shown in a simplified form in Figure 4. Also, for convenience, fixed die 42 of mold 40 is not shown in Figures 4 to 6. Mold 40 is a mold used in injection molding apparatus 100.

[0049] 4, the forming die 40 is formed by fitting the laminate 142 into a recess 149 provided in a matrix 148. The matrix 148 is made of a material such as metal.

[0050] 6, the laminate 142 has a plurality of layers 144. The laminate 142 is configured by stacking the plurality of layers 144. The number of the plurality of layers 144 is not particularly limited. The laminate 142 is a core.

[0051] The laminate 142 has a cavity 140. The shape of the cavity 140 corresponds to the shape of the molded product to be molded by the injection molding apparatus 100. The cavity 140 is defined by the laminate 142. As shown in FIG. 5, a through hole 141 into which the ejector pin 44 is inserted is provided in the bottom surface of the cavity 140. In the illustrated example, two through holes 141 are provided.

[0052] 6, the laminate 142 has a cooling pipe 146. In the illustrated example, the cooling pipe 146 is provided in the +Y-axis direction of the cavity 140. A refrigerant for cooling the molded product flows through the cooling pipe 146. An example of the refrigerant is water.

[0053] Such a molding die 40 is manufactured by a three-dimensional modeling method using a three-dimensional modeling composition containing inorganic particles surface-modified with a silane coupling agent and a thermoplastic resin. More specifically, as described below, the molding die is manufactured by a molding die manufacturing method including a step of plasticizing the three-dimensional modeling composition to produce a plasticized composition, and a step of ejecting the plasticized composition toward a stage to stack layers 144, thereby forming a laminate 142 that becomes a part of the molding die 40.

[0054] [2] Composition for three-dimensional modeling Next, the composition for forming a three-dimensional object of the present invention will be described in detail.

[0055] The composition for three-dimensional modeling of the present invention contains inorganic particles surface-modified with a silane coupling agent and a thermoplastic resin, and the content of the silane coupling agent relative to the unit surface area of ​​the inorganic particles is 0.00233 g / m 2 More than 0.00933g / m 2 The following is the result.

[0056] By satisfying these conditions, it is possible to provide a composition for three-dimensional modeling that has excellent strength and in which shedding of inorganic particles is effectively suppressed, and that can be suitably used for producing a shaped object. In particular, it is possible to provide a composition for three-dimensional modeling that has excellent strength and in which shedding of inorganic particles is effectively suppressed, and that can be suitably used for producing a molding die for injection molding, which is a shaped object, that has excellent strength and in which shedding of inorganic particles is effectively suppressed.

[0057] More specifically, by surface-modifying the inorganic particles with a silane coupling agent, the adhesion between the inorganic particles and the thermoplastic resin is enhanced, thereby improving the mechanical strength of the resulting shaped article and suppressing the detachment of the inorganic particles from the surface of the shaped article. Furthermore, by setting the content of the silane coupling agent relative to the unit surface area of ​​the inorganic particles within the above-mentioned ranges, the mechanical strength, rigidity, and elastic modulus of the shaped article can be made particularly excellent.

[0058] On the other hand, if the above conditions are not met, the above excellent effects cannot be obtained.

[0059] For example, if the inorganic particles are not surface-modified with a silane coupling agent, the adhesion to the thermoplastic resin will not be sufficiently high, the mechanical strength of the resulting shaped article will not be sufficiently high, and the inorganic particles will be prone to detachment from the surface of the resulting shaped article.

[0060] Furthermore, even if the inorganic particles are surface-modified with a silane coupling agent, if the content of the silane coupling agent relative to the unit surface area of ​​the inorganic particles is less than the above-mentioned lower limit, the strength and rigidity of the resulting shaped object may be reduced, whereas if the content of the silane coupling agent relative to the unit surface area of ​​the inorganic particles is greater than the above-mentioned upper limit, the elastic modulus of the shaped object may be reduced.

[0061] In this specification, the term "composition for three-dimensional modeling" refers to a composition that is applied to a three-dimensional modeling method and used to produce a model having a layered structure in which multiple layers are stacked.

[0062] Furthermore, the composition for three-dimensional modeling and the object produced using the composition for three-dimensional modeling have substantially the same composition. Therefore, by satisfying the preferred compositional conditions described below, the molding die of the present invention can exhibit the effects described below.

[0063] The following description will mainly focus on the case where the laminate 142 of the above-described forming die 40 is produced as a shaped object by a three-dimensional modeling method using the composition for three-dimensional modeling of the present invention.

[0064] [2-1]Inorganic particles The composition for three-dimensional modeling contains inorganic particles.

[0065] Examples of inorganic materials constituting the inorganic particles include various metals and metal compounds, etc. Examples of metal compounds include various metal oxides, various metal hydroxides, various metal nitrides, various metal carbides, various metal sulfides, various metal carbonates, various metal sulfates, various metal silicates, various metal phosphates, various metal borates, talc, mica, etc., and composites thereof.

[0066] Examples of metal oxides include silica, alumina, titanium oxide, zinc oxide, zirconium oxide, tin oxide, magnesium oxide, sodium oxide, barium titanate, and potassium titanate.

[0067] Examples of metal hydroxides include magnesium hydroxide, aluminum hydroxide, and calcium hydroxide.

[0068] Examples of metal nitrides include silicon nitride, titanium nitride, and aluminum nitride. Examples of metal carbides include silicon carbide and titanium carbide.

[0069] An example of the metal sulfide is zinc sulfide. Examples of metal carbonates include calcium carbonate and magnesium carbonate.

[0070] Examples of metal sulfates include calcium sulfate and magnesium sulfate. Examples of metal silicates include calcium silicate and magnesium silicate.

[0071] Examples of metal phosphates include calcium phosphate. Examples of metal borates include aluminum borate and magnesium borate.

[0072] The inorganic particles may include an amorphous metal. Amorphous metals generally have a lower thermal conductivity than metals other than amorphous metals and a higher thermal conductivity than resins. Therefore, when a molded article is produced using the mold, the inorganic particles containing amorphous metals reduce the heat trapped in the mold, shortening the cooling time of the molded article, while more effectively suppressing defects such as chipping and warping of the molded article caused by insufficient filling of the three-dimensional modeling composition into the mold. The amorphous metal contains, for example, iron, cobalt, nickel, or the like as a main component.

[0073] The term "major component" refers to the component that accounts for the largest proportion in the target substance, and is preferably a component that accounts for 50% by mass or more.

[0074] The amorphous metal may contain, in addition to the above components, other metal components such as tungsten, niobium, tantalum, titanium, zirconium, and hafnium. The inorganic particles may have any shape, but are preferably spherical.

[0075] This allows the manufacture of a mold having a smaller difference in elastic modulus between a first direction and a second direction that are perpendicular to each other, compared to when the inorganic particles are not spherical. As a result, the mechanical properties of the mold can be stabilized. Furthermore, the degree of freedom in design can be increased. Furthermore, the flowability of the three-dimensional modeling composition can be improved, and the productivity of molds using the three-dimensional modeling composition can be particularly improved.

[0076] The average particle size of the inorganic particles is not particularly limited, but is preferably from 1 μm to 50 μm, and more preferably from 1 μm to 25 μm.

[0077] This makes it possible to particularly improve the mechanical strength of a molding die produced using the composition for three-dimensional modeling, more effectively prevent the occurrence of undesired irregularities in the molding die, and improve the dimensional accuracy of the molding die. It also improves the flowability of the composition for three-dimensional modeling, improving the productivity of molding die using the composition for three-dimensional modeling. It also makes it possible to more effectively prevent inorganic particles from falling off the surface of the molding die.

[0078] In this specification, 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 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.

[0079] The content of inorganic particles in the composition for three-dimensional modeling is preferably 1% by volume or more and 50% by volume or less, more preferably 5% by volume or more and 45% by volume or less, and even more preferably 10% by volume or more and 43% by volume or less.

[0080] This allows the three-dimensional modeling composition to have sufficiently excellent fluidity, while the finally obtained molding die has particularly excellent mechanical strength.

[0081] The inorganic particles may be surface-modified at least with a silane coupling agent, which will be described in detail later, and may also be surface-modified with other surface treatment agents in addition to the surface modification with the silane coupling agent.

[0082] [2-1-1] Silane coupling agents The inorganic particles are surface-modified with a silane coupling agent.

[0083] The silane coupling agent has the function of modifying the surface of the inorganic particles and improving the affinity with the thermoplastic resin.

[0084] Specifically, when the surface of inorganic particles is treated with a silane coupling agent, the alkoxy groups of the silane coupling agent are hydrolyzed to OH groups. The OH groups present on the surface of the inorganic particles then form hydrogen bonds with the OH groups of the silane coupling agent, adhering to the surface of the inorganic particles. Further dehydration condensation generates inorganic particle-oxygen-silicon bonds, which adhere to the surface of the inorganic particles. This bond is a stable covalent bond and is not thermally cleaved.

[0085] When the silane coupling agent is bonded to the surface of the inorganic particles, the functional group that interacts with the thermoplastic resin is exposed on the outer surface. The functional group has reactivity and compatibility with the thermoplastic resin, and the chemical bond and affinity between the functional group of the silane coupling agent and the thermoplastic resin can enhance the bonding strength between the inorganic particles and the thermoplastic resin. This allows the final molding die to have excellent mechanical strength. Furthermore, the inorganic particles are prevented from falling off the surface of the molding die.

[0086] Examples of functional groups that interact with thermoplastic resins include thiol groups, amino groups, methacrylic groups, and acrylic groups.

[0087] Examples of silane coupling agents include amino-based silane coupling agents, acrylic-based silane coupling agents, ureido-based silane coupling agents, vinyl-based silane coupling agents, methacrylic-based silane coupling agents, epoxy-based silane coupling agents, mercapto-based silane coupling agents, isocyanate-based silane coupling agents, etc. Among these, amino-based silane coupling agents and acrylic-based silane coupling agents are particularly preferred, and amino-based silane coupling agents containing at least one primary amine are more preferred.

[0088] This makes it possible to further increase the affinity between the inorganic particles and the thermoplastic resin.

[0089] Specific examples of the silane coupling agent include vinyltrimethoxysilane, vinyltriethoxysilane, phenyltriethoxysilane, 3-(acryloxy)propyltrimethoxysilane, N-2-aminoethyl-3-aminopropylmethyldimethoxysilane, γ-aminopropylmethyldiethoxysilane, γ-aminopropyltriethoxysilane, N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, and the like. Examples of suitable silanes include thoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, vinyltris(β-methoxyethoxy)silane, β-(3,4-epoxycyclohexyl)-ethyltrimethoxysilane, γ-phenylaminopropyltrimethoxysilane, ureidopropyltrimethoxysilane, ureidopropyltriethoxysilane, γ-isocyanatopropyltrimethoxysilane, and γ-isocyanatopropyltriethoxysilane.

[0090] The silane coupling agent preferably has an OH group as a functional group. The OH groups of the silane coupling agent undergo a dehydration condensation reaction with the OH groups present on the surface of the inorganic particles, forming an inorganic particle-oxygen-silicon bond. This covalent bond formation reaction fixes the silane coupling agent to the surface of the inorganic particles.

[0091] Even when a general silane coupling agent having an alkoxy group but no OH group is used, the reaction in which the alcohol corresponding to the alkoxy group is eliminated from the silane coupling agent, i.e., the hydrolysis reaction, can be carried out first, and then the covalent bond formation reaction as described above can be carried out. However, when a general silane coupling agent having an alkoxy group but no OH group is used, the alcohol, which is a volatile organic compound, is released as a gas outside the system, requiring environmental measures. Furthermore, when a general silane coupling agent having an alkoxy group but no OH group is used, when a molding die is produced using the three-dimensional modeling composition, bubbles caused by the alcohol are mixed into the plasticized three-dimensional modeling composition, making the resulting molding die prone to defects such as chips and voids.

[0092] In contrast, the use of a silane coupling agent having an OH group as a functional group can effectively prevent the occurrence of the above-mentioned problems, and also can omit or simplify the hydrolysis reaction step, thereby improving the productivity of the composition for three-dimensional modeling.

[0093] Such silane coupling agents are generally non-flammable and can reduce the amount of volatile organic compounds generated, and are therefore advantageous from the standpoint of environmental protection.

[0094] The silane coupling agent having an OH group as a functional group as described above can be suitably produced by carrying out a hydrolysis reaction using a general silane coupling agent having an alkoxy group but no OH group as a raw material.

[0095] The content of silane coupling agent per unit surface area of ​​inorganic particles is 0.00233 g / m 2 More than 0.00933g / m 2 Preferably, it is 0.003 g / m or less. 2 More than 0.008g / m 2 More preferably, it is 0.004 g / m or less. 2 More than 0.006g / m2 More preferably, it is: This makes the above-mentioned effects more pronounced.

[0096] Furthermore, the content of the silane coupling agent relative to 100 parts by mass of inorganic particles is preferably 0.05 parts by mass or more and 0.2 parts by mass or less, more preferably 0.06 parts by mass or more and 0.18 parts by mass or less, and even more preferably 0.08 parts by mass or more and 0.15 parts by mass or less.

[0097] This makes it possible to more effectively suppress the generation of gas, and also to further improve the mechanical strength, rigidity, and elastic modulus of the produced molding die.

[0098] [2-2]Thermoplastic resin The composition for three-dimensional modeling contains a thermoplastic resin.

[0099] Examples of thermoplastic resins include polyphenylene sulfide, ABS resin, polypropylene, polyethylene, polyacetal, polyvinyl chloride, polyamide, polylactic acid, polycarbonate, modified polyphenylene ether, polybutylene terephthalate, polyethylene terephthalate, polysulfone, polyethersulfone, polyarylate, polyimide, polyamideimide, polyetherimide, polyetheretherketone, etc. Among these, polyphenylene sulfide, polyimide, and polyetheretherketone are particularly preferred.

[0100] The content of the thermoplastic resin in the composition for three-dimensional modeling is preferably 40% by volume or more and 99% by volume or less, more preferably 50% by volume or more and 95% by volume or less, and even more preferably 55% by volume or more and 90% by volume or less.

[0101] This allows the flowability of the composition for three-dimensional formation to be sufficiently excellent, while also improving the mechanical strength of the mold to be produced.

[0102] [2-3] Other ingredients The composition for forming a three-dimensional object may contain components other than the components described above. Hereinafter, such components will also be referred to as other components.

[0103] Examples of other components include inorganic particles whose surfaces are not modified with a silane coupling agent, colorants, fixing agents, antifungal agents, preservatives, antioxidants, ultraviolet absorbers, chelating agents, and pH adjusters.

[0104] The content of other substances in the composition for three-dimensional forming is preferably 10% by mass or less, more preferably 7% by mass or less, and even more preferably 5% by mass or less.

[0105] [3] Manufacturing method of molding die Next, a method for manufacturing the mold will be described with reference to the drawings. FIG. 7 is a flowchart illustrating the method for manufacturing the molding die.

[0106] First, as shown in FIG. 7, in step S1, a composition for three-dimensional modeling containing an amorphous metal and a thermoplastic resin is plasticized to produce a plasticized composition. The composition for three-dimensional modeling contains inorganic particles whose surfaces have been modified with a silane coupling agent, and a thermoplastic resin.

[0107] The composition for three-dimensional modeling is prepared, for example, by kneading inorganic particles surface-modified with a silane coupling agent and a thermoplastic resin in a twin-screw extruder. In preparing the composition for three-dimensional modeling, in addition to the inorganic particles surface-modified with a silane coupling agent and the thermoplastic resin, other components may also be used.

[0108] In the step of producing the plasticized composition, for example, a flat screw is used to produce the plasticized composition as described below.

[0109] Next, in step S2, the plasticized composition is ejected toward the stage to laminate layers 144, thereby forming a laminate 142 that will become a part of the mold 40. In the step of forming the laminated body 142, for example, the laminated body 142 having the cooling pipes 146 is formed.

[0110] Next, in step S3, the laminate 142 is cut to form the cavity 140. The cutting of the laminate 142 is performed using, for example, a cutting tool as described below. Note that the cavity 140 may be formed in the process of forming the laminate 142 in step S2. In this case, step S3 may be omitted.

[0111] Next, in step S4, the laminate 142 is fitted into a matrix 148 as shown in FIG. Through the steps described above, the molding die 40 can be manufactured.

[0112] [4] Three-dimensional printing equipment Next, a three-dimensional modeling device used in the method for manufacturing a molding die will be described. The method for manufacturing the molding die is carried out using a three-dimensional modeling device. Figure 8 is a diagram showing a schematic configuration example of a three-dimensional modeling device used to manufacture the molding die. The three-dimensional modeling device 60 models a laminate 142 that becomes a part of the molding die 40.

[0113] As shown in FIG. 8, the three-dimensional modeling apparatus 60 includes a modeling unit 150, a cutting unit 160, a stage 170, a moving mechanism 180, and a control unit 190.

[0114] The three-dimensional modeling device 60 drives the movement mechanism 180 to change the relative position between the nozzle 156 and the stage 170 while discharging the plasticized composition from the nozzle 156 of the modeling unit 150 onto the stage 170. In this way, the modeling unit 150 stacks the laminate 142 on the stage 170. For convenience, the laminate 142 is illustrated in a simplified form in FIG. 8 .

[0115] Furthermore, the three-dimensional modeling device 60 drives the movement mechanism 180 while rotating the cutting tool 162 of the cutting unit 160, thereby changing the relative position between the cutting tool 162 and the stage 170. In this way, the cutting unit 160 cuts the laminate 142 stacked on the stage 170. In this way, the three-dimensional modeling device 60 models the laminate 142 in a desired shape.

[0116] Here, FIG. 9 is a cross-sectional view schematically showing the modeling unit 150. As shown in FIG. As shown in FIG. 9, the modeling unit 150 includes, for example, a material supply unit 152, a plasticizing unit 154, and a nozzle 156.

[0117] The material supply unit 152 supplies the modeling material to the plasticizing unit 154. The modeling material is input into the material supply unit 152. The modeling material is, for example, a three-dimensional modeling composition in pellet or powder form. The material supply unit 152 is configured, for example, by a hopper. The material supply unit 152 and the plasticizing unit 154 are connected by a supply path 153 provided below the material supply unit 152. The modeling material input into the material supply unit 152 is supplied to the plasticizing unit 154 via the supply path 153.

[0118] The plasticizing unit 154 has a configuration similar to that of the plasticizing device 10 of the injection molding apparatus 100 shown in Figure 1. In other words, the plasticizing unit 154 has a flat screw 154a, a barrel 154b, and a heater 154c. The plasticizing unit 154 plasticizes the molding material supplied from the material supply unit 152 to produce a fluid, paste-like plasticized composition, which is then guided to a nozzle hole 158 provided in a nozzle 156.

[0119] The nozzle 156 ejects the plasticized composition produced by the plasticizing section 154 toward the stage 170 .

[0120] As shown in FIG. 8 , the cutting unit 160 is a device that rotates a cutting tool 162 attached to the tip on the stage 170 side to cut the laminate 142 stacked on the stage 170. The cutting unit 160 cuts the laminate 142 to form the cavity 140, for example. A flat end mill or a ball end mill is used as the cutting tool 162. The control unit 190 controls the movement mechanism 180 to change the relative positions of the cutting tool 162 and the laminate 142 stacked on the stage 170, thereby controlling the cutting position.

[0121] The laminate 142 is stacked on the stage 170. In the illustrated example, the laminate 142 is provided directly on the stage 170. Although not illustrated, the laminate 142 may also be provided on the stage 170 via a base plate. Then, the molding die 40 may be manufactured by fitting the laminate 142 and the base plate into the matrix 148.

[0122] The movement mechanism 180 supports the stage 170. In the illustrated example, the movement mechanism 180 is configured as a three-axis positioner that moves the stage 170 along three axes that are perpendicular to each other relative to the modeling unit 150 and the cutting unit 160.

[0123] The moving mechanism 180 may move the modeling unit 150 and the cutting unit 160 relative to the stage 170 without moving the stage 170. Alternatively, the moving mechanism 180 may move both the stage 170 and the modeling unit 150 and the cutting unit 160. The moving mechanism 180 may have a function to tilt the stage 170 with respect to a horizontal plane. The moving mechanism 180 may have a function to tilt the nozzle 156 or the cutting tool 162.

[0124] The control unit 190 is configured, for example, by a computer having a processor, a main storage device, and an input / output interface for inputting and outputting signals to and from the outside. The control unit 190 controls the modeling unit 150, the cutting unit 160, and the movement mechanism 180, for example, by the processor executing a program loaded into the main storage device. Note that the control unit 190 may be configured not by a computer but by a combination of multiple circuits.

[0125] 10A to 10C are cross-sectional views schematically showing the manufacturing process of the laminate 142 in the three-dimensional modeling apparatus 60. As shown in FIG.

[0126] 10 , the control unit 190 discharges the plasticizing composition from the nozzle 156 while changing the position of the nozzle 156 relative to the stage 170 in a direction along the upper surface of the stage 170, while maintaining the distance between the stage 170 and the nozzle 156. The plasticizing composition discharged from the nozzle 156 is continuously deposited on the stage 170 in the direction of movement of the nozzle 156, and a layer 144 is formed.

[0127] The control unit 190 repeatedly scans the nozzle 156 to form multiple layers 144. Specifically, after forming one layer 144, the control unit 190 moves the position of the nozzle 156 upward relative to the stage 170. Then, the stacked body 142 is formed by stacking additional layers 144 on top of the layers 144 that have been formed so far.

[0128] The control unit 190 may temporarily suspend the discharge of the plasticizing composition from the nozzle 156, for example, when moving the nozzle 156 upward after depositing one layer 144, or when forming discontinuous paths. In this case, the control unit 190 controls a butterfly valve (not shown) or the like provided in the nozzle hole 158 to stop the discharge of the plasticizing composition from the nozzle 156. After changing the relative position of the nozzle 156 with respect to the stage 170 as necessary, the control unit 190 opens the butterfly valve to resume the discharge of the plasticizing composition, thereby resuming the deposition of the plasticizing composition.

[0129] In this manner, the laminate 142 that constitutes a part of the mold 40 used in the injection molding apparatus 100 is manufactured.

[0130] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these.

[0131] For example, in the present invention, in addition to the above-described composition for three-dimensional modeling, a composition other than the above-described composition for three-dimensional modeling may be used.

[0132] Furthermore, in the method for producing a molding die, the order of steps and treatments is not limited to that described above, and at least some of them may be reversed.

[0133] In the method for producing the molding die, a pre-treatment step, an intermediate treatment step, and a post-treatment step may be carried out as necessary.

[0134] Furthermore, in the three-dimensional modeling apparatus, the configuration of each part can be replaced with any configuration that exhibits the same function, and any configuration can also be added.

[0135] Furthermore, the mold is not limited to one manufactured using the three-dimensional modeling device described above.

[0136] Furthermore, the injection molding device and the molding die are not limited to those having the above-mentioned configurations. The composition for three-dimensional modeling can also be used to produce a shaped object other than the above-mentioned mold. [Example]

[0137] The present invention will be described in more detail below with reference to specific examples, but the present invention is not limited to these examples. In the following description, treatments for which no temperature conditions are specified were performed at room temperature, specifically 25°C. Furthermore, various measurement conditions for which no temperature conditions are specified are values ​​at room temperature, specifically 25°C.

[0138] [5] Preparation of composition for three-dimensional modeling Example 1 A composition for three-dimensional modeling was prepared by mixing and kneading a polyphenylene sulfide resin as a thermoplastic resin and inorganic particles whose surfaces had been modified with a silane coupling agent.

[0139] The polyphenylene sulfide resin used was FZ-2100 manufactured by DIC Corporation, the inorganic particles used were AW2-08 PF5-F manufactured by Epson Atmix, which is iron powder with an average particle size of 4 μm, and the silane coupling agent used was KBP-90 manufactured by Shin-Etsu Chemical Co., Ltd.

[0140] The prepared composition for three-dimensional modeling contained 60% by volume of polyphenylene sulfide resin and 40% by volume of inorganic particles surface-modified with a silane coupling agent. The content of the silane coupling agent relative to the unit surface area of ​​the inorganic particles was 0.004667 g / m. 2 The content of the silane coupling agent relative to 100 parts by mass of the inorganic particles was 0.1 parts by mass.

[0141] The content of the silane coupling agent per unit surface area of ​​the inorganic particles was calculated assuming that all the inorganic particles were true spheres having a diameter equal to the average particle size. The same applies to the following examples and comparative examples.

[0142] Example 2 A three-dimensional modeling composition was prepared in the same manner as in Example 1, except that KBM-803 manufactured by Shin-Etsu Chemical Co., Ltd. was used as the silane coupling agent instead of KBP-90 manufactured by Shin-Etsu Chemical Co., Ltd., and the amount of silane coupling agent used relative to the inorganic particles was changed to obtain the configuration shown in Figure 11.

[0143] (Examples 3 and 4) A three-dimensional modeling composition was prepared in the same manner as in Example 1, except that a polyether ether ketone resin was used instead of a polyphenylene sulfide resin as the thermoplastic resin, and the average particle size of the inorganic particles was set as shown in Fig. 11, resulting in the configuration shown in Fig. 11. Note that VICTREX PEEK 90G manufactured by VICTREX was used as the polyether ether ketone resin.

[0144] (Comparative Example 1) A composition for three-dimensional modeling was prepared in the same manner as in Example 1, except that the inorganic particles were not surface-modified with a silane coupling agent.

[0145] (Comparative Example 2) The content of silane coupling agent per unit surface area of ​​inorganic particles is 0.000933 g / m 2 A composition for three-dimensional modeling was prepared in the same manner as in Example 1, except that the above-mentioned conditions were changed.

[0146] In Figure 11, polyphenylene sulfide resin is indicated as "PPS," polyether ether ketone resin as "PEEK," silane coupling agent as "SCA," KBP-90 manufactured by Shin-Etsu Chemical Co., Ltd. as "KBP-90," and KBM-803 manufactured by Shin-Etsu Chemical Co., Ltd. as "KBM-803." The structures of the silane coupling agents are shown below.

[0147] [ka]

[0148] [ka]

[0149] [6] Evaluation The three-dimensional modeling compositions obtained as described above were evaluated as follows.

[0150] [6-1] Measurement of bending stress and elastic modulus Using the compositions for three-dimensional modeling of each of the Examples and Comparative Examples, plate-shaped test pieces measuring 50 mm in length, 10 mm in width, and 4 mm in thickness were prepared by injection molding.

[0151] The bending stress and flexural modulus of each specimen were measured using a three-point bending test fixture in accordance with the method described in JIS K7171:2016. The distance between the supports of the bending test fixture was 40 mm, and the bending speed was 1 mm / min. The measurement range for the flexural modulus was a strain range of 0.05% to 0.25%. Measurements were carried out on five test pieces for each test, and the average value was calculated.

[0152] FIG. 11 is a table showing the evaluation results of the compositions for three-dimensional modeling of the examples and comparative examples, along with their compositions.

[0153] As is clear from Figure 11, the present invention produced a molded article with excellent mechanical strength. By using a molded article with such high mechanical strength as a mold for use in an injection molding machine, it is possible to reduce the possibility of damage to the mold's fine structures or thin-walled portions, even when high pressures, for example, 100 MPa to 200 MPa, are applied during injection molding. In contrast, the comparative example did not produce satisfactory results.

[0154] Instead of injection molding, a three-dimensional modeling method using a three-dimensional modeling device as shown in Figures 8 and 9 was adopted to fabricate plate-shaped test pieces measuring 50 mm in length, 10 mm in width, and 4 mm in thickness using the three-dimensional modeling compositions of each of the Examples and Comparative Examples. The bending stress and bending modulus of these test pieces were measured in the same manner as above, and excellent results were obtained, as above.

[0155] [6-2] Evaluation of molding molds A three-dimensional modeling apparatus as shown in FIGS. 8 and 9 was prepared, and the laminates shown in FIGS. 5 and 6 were produced using the compositions for three-dimensional modeling of the above-described Examples and Comparative Examples, respectively. Using each of the laminates thus obtained, a molding die shown in FIG. 4 was obtained.

[0156] Using an injection molding machine (see FIGS. 1 to 3) equipped with the mold, molded articles were repeatedly produced by injection molding, with the injection molding pressure set to 200 MPa.

[0157] Thereafter, when the molding dies according to the respective Examples and Comparative Examples were visually observed, no dropout of inorganic particles was observed in the molding dies of the respective Examples, and no defects such as chipping occurred. Furthermore, no defects resulting from the above-mentioned defects were observed in the molded articles produced using the molding dies of the respective Examples.

[0158] In contrast, in the molding dies of each comparative example, the inorganic particles were observed to fall off and chipping occurred. Furthermore, in the molded articles produced using the molding dies of each comparative example, defects due to the chipping were observed.

[0159] [6-3] Evaluation of vacancy generation A three-dimensional modeling apparatus as shown in FIGS. 8 and 9 was prepared, and the compositions for three-dimensional modeling of each of the Examples and Comparative Examples were plasticized and discharged in the form of strings from a nozzle to obtain strands.

[0160] Figure 12 shows image processing results (VHV (digital microscope)) of strands ejected using the composition for three-dimensional modeling of Example 1, which contains KBP-90 manufactured by Shin-Etsu Chemical Co., Ltd. as a silane coupling agent. Figure 13 shows image processing results (VHV (digital microscope)) of strands ejected using the composition for three-dimensional modeling of Example 2, which contains KBM-803 manufactured by Shin-Etsu Chemical Co., Ltd. as a silane coupling agent.

[0161] 12 and 13, the compositions for three-dimensional modeling according to the present invention were able to effectively suppress the generation of voids, whereas the comparative examples showed a large number of voids.

[0162] 12 and 13, Example 1, which used KBP-90, a silane coupling agent having an OH group as a functional group, had fewer voids in the strands than Example 2, which used KBM-803, a silane coupling agent not having an OH group as a functional group. A similar tendency was confirmed in the comparative examples. [Explanation of symbols]

[0163] 10...plasticizing device, 12...screw case, 14...drive motor, 20...injection mechanism, 22...cylinder, 24...plunger, 26...plunger drive unit, 30...nozzle, 32...nozzle hole, 40...molding mold, 41...movable mold, 42...fixed mold, 43...extrusion mechanism, 44...ejector pin, 45...support plate, 46...support rod, 47...spring, 48...extrusion plate, 49...thrust bearing, 50...mold clamping device, 52...molding mold drive unit, 54...ball screw, 60...three-dimensional modeling device, 100...injection molding device, 110...flat screw, 111...main surface, 112...groove forming surface, 113...connecting surface, 114...second 1 groove, 115...central portion, 116...connection portion, 117...material introduction portion, 120...barrel, 122...opposing surface, 124...second groove, 126...communicating hole, 130...heater, 140...cavity, 141...through hole, 142...laminated body, 144...layer, 146...cooling pipe, 148...mold, 149...recess, 150...molding unit, 152...material supply portion, 153...supply path, 154...plasticization portion, 154a...flat screw, 154b...barrel, 154c...heater, 156...nozzle, 158...nozzle hole, 160...cutting unit, 162...cutting tool, 170...stage, 180...movement mechanism, 190...control portion, RA...rotation axis, S1...step, S2...step, S3...step, S4...step

Claims

1. A mold used in injection molding, It has a laminated structure in which a plurality of layers are laminated, The material is made of a material containing inorganic particles surface-modified with a silane coupling agent and a thermoplastic resin, A molding die having a bending stress of 120 MPa or more in a three-point bending strength test.

2. The mold according to claim 1, wherein the mold has an elastic modulus of 8,300 MPa or more in a three-point bending strength test.

3. The content of the silane coupling agent relative to the unit surface area of ​​the inorganic particles is 0.00233 g / m ２ 0.00933g / m or more ２ The mold according to claim 1 or 2, wherein:

4. 3. The mold according to claim 1, wherein the content of the silane coupling agent is 0.05 parts by mass or more and 0.2 parts by mass or less relative to 100 parts by mass of the inorganic particles.

5. The mold according to claim 1 or 2, wherein the silane coupling agent has an OH group as a functional group.

6. The mold according to claim 1 or 2, wherein the inorganic particles include amorphous metal.

7. 3. The mold according to claim 1, wherein the inorganic particles are spherical iron powder.

8. The composite material includes inorganic particles surface-modified with a silane coupling agent and a thermoplastic resin, The content of the silane coupling agent relative to the unit surface area of ​​the inorganic particles is 0.00233 g / m ２ 0.00933g / m or more ２ A composition for three-dimensional modeling, which is as follows:

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