Powder for stacked molding

Abstract

A powder for stacked shaping, which is an inorganic oxide powder, with D10 being 1.0 to 4.0 μm, D50 being 5.5 to 9.0 μm, D90 being 20.0 to 40.0 μm, and the volume ratio of particles with a particle size of 16.8 to 60.0 μm being 15.0 to 22.0 vol%.

Description

Technical Field

[0001] The present disclosure relates to a powder for laminated modeling, a sintered body thereof, and a method for manufacturing an adhesive jet laminated modeling body. Background Art

[0002] In recent years, processing methods such as additive manufacturing (AM) technology and 3D printing technology have attracted attention. This is a technology for obtaining a target modeling body by creating cross-sectional shapes based on three-dimensional shape data of the target modeling body and laminating them. As additive manufacturing technologies, there are known: an adhesive jet type in which an adhesive is sprayed onto a powder material on a modeling table to selectively model (Patent Document 1); a material jet type in which a photocurable resin or the like is sprayed from an inkjet nozzle to selectively model; a powder bed melting type in which a laser or electron beam is irradiated onto a powder bed filled with metal powder or the like to selectively melt and model; a photocuring method in which light is irradiated onto a slurry in which a liquid photocurable resin and inorganic powder are mixed to model (Patent Document 2), and other processing methods.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2016-117069

[0006] Patent Document 2: Japanese Unexamined Patent Application Publication No. 2021-11050 Summary of the Invention

[0007] The adhesive jet method is also known by the term "3D inkjet powder printing". This method has, for example: a step of supplying a powder material to a modeling table using a roller to form a uniform powder layer; and a step of applying a liquid adhesive to the powder layer by an inkjet print head to selectively bond a part of the powder layer. By repeating these steps, a target three-dimensional laminated modeling body can be obtained. Then, the three-dimensional laminated modeling body is sintered as needed. In the adhesive jet method, a structure with uneven distribution of constituent materials such as voids sometimes occurs in the obtained three-dimensional laminated modeling body. To suppress this, it is desired that the powder for laminated modeling has good spreadability that can be smoothly supplied to the modeling table and evenly spread. In addition, it is considered that a three-dimensional laminated modeling body with high uniformity can be obtained by filling the powder for laminated modeling at a high density. To achieve good spreadability and high-density filling, it is useful to improve the fluidity of the powder material. On the other hand, when applying the adhesive, it is also required that the powder layer is not disturbed and the adhesive can enter between the powder materials. Moreover, a low shrinkage rate during sintering is also desired.

[0008] The present disclosure provides a material which, as a powder for laminated modeling, has a moderate fluidity that combines good layability capable of forming a uniform powder layer and shape stability capable of maintaining its shape during the period from the application of the binder to the sintering treatment, and has a moderate bulk density that enables the binder to enter between the powder materials and achieves a low shrinkage rate during sintering.

[0009] The present inventors have found that by controlling the volume ratio of particles with relatively large particle sizes within a specific range in the powder for laminated modeling, the fluidity and bulk density of the powder for laminated modeling can be controlled within an appropriate range. Moreover, the present inventors have found that by blending two inorganic oxide powders having different particle size distributions in a prescribed ratio, the fluidity and bulk density of the powder material can be controlled within an appropriate range.

[0010] The content of the present disclosure relates to the following matters.

[0011] [1] A powder for laminated modeling, which is an inorganic oxide powder,

[0012] D10 is 1.0 to 4.0 μm, D50 is 5.5 to 9.0 μm, D90 is 20.0 to 40.0 μm,

[0013] The volume ratio of particles having a particle size of 16.8 to 60.0 μm is 15.0 to 22.0 vol%.

[0014] [2] The powder for laminated modeling according to [1], wherein the volume ratio of particles having a particle size of 2.0 μm or more is 90.0 to 100 vol%.

[0015] [3] The powder for laminated modeling according to [1] or [2],

[0016] The ratio of D50 to D10 (D50 / D10) is 2.0 to 2.2,

[0017] The ratio of D90 to D10 (D90 / D10) is 6.0 to 8.0.

[0018] [4] The powder for laminated modeling according to any one of [1] to [3], having a BET specific surface area of 0.1 to 10.0 m 2 / g.

[0019] [5] The powder for laminated modeling according to any one of [1] to [4], having a spherical shape.

[0020] [6] The powder for laminated modeling according to any one of [1] to [5], which is alumina.

[0021] [7] The powder for laminated modeling according to [6] has a green compact volume density of 2.52 to 2.54 g / cm³ under a pressure of 98 MPa. 3 .

[0022] [8] The powder for laminated modeling according to any one of [1] to [7] is used in the binder jetting method.

[0023] [9] A sintered body is a sintered body of the powder for laminated modeling according to any one of [1] to [7].

[0024]

[10] A method for manufacturing an adhesive jet laminated model includes: applying a liquid containing an adhesive to the powder for laminated modeling according to any one of [1] to [7] to form a three-dimensional laminated model.

[0025]

[11] A method for manufacturing a sintered body includes:

[0026] applying a liquid containing an adhesive to the powder for laminated modeling according to any one of [1] to [7] to form a three-dimensional laminated model; and

[0027] sintering the three-dimensional laminated model.

[0028]

[12] A powder for laminated modeling includes:

[0029] coarse inorganic oxide powder (A) with a D50 of 9.0 to 25.0 μm; and

[0030] fine inorganic oxide powder (B) with a D50 smaller than that of the coarse inorganic oxide powder (A),

[0031] and the volume ratio of the coarse inorganic oxide powder (A) is 9.5 to 29.0 vol% based on the total volume of the coarse inorganic oxide powder (A) and the fine inorganic oxide powder (B).

[0032]

[13] For the powder for laminated modeling according to

[12] , the particle size volume ratio of the coarse inorganic oxide powder (A) to the fine inorganic oxide powder (B) is 0.26 to 1.15.

[0033]

[14] For the powder for laminated modeling according to

[12] or

[13] , the D50 (D A 50) of the coarse inorganic oxide powder (A) and the D50 (D B 50) of the fine inorganic oxide powder (B) satisfy D A 50 - D B 50 ≥ 3.5 μm.

[0034]

[15] A powder for laminated modeling, comprising:

[0035] Coarse-grained inorganic oxide powder (A) with a D50 of 9.0 to 25.0 μm; and

[0036] Fine-grained inorganic oxide powder (B) with a D50 smaller than that of the coarse-grained inorganic oxide powder (A),

[0037] The particle size volume ratio of the coarse-grained inorganic oxide powder (A) to the fine-grained inorganic oxide powder (B) is 0.26 to 1.15.

[0038]

[16] The powder for laminated modeling according to

[15] , the volume ratio of the coarse-grained inorganic oxide powder (A) is 9.5 to 29.0 vol% based on the total volume of the coarse-grained inorganic oxide powder (A) and the fine-grained inorganic oxide powder (B).

[0039]

[17] The powder for laminated modeling according to

[15] or

[16] , the D50 (D A 50) of the coarse-grained inorganic oxide powder (A) and the D50 (D B 50) of the fine-grained inorganic oxide powder (B) satisfy D A 50 - D B 50 ≥ 3.5 μm.

[0040]

[18] The powder for laminated modeling according to any one of

[12] to

[17] , the D50 of the fine-grained inorganic oxide powder (B) is 5.0 to 8.0 μm.

[0041]

[19] The powder for laminated modeling according to any one of

[12] to

[18] ,

[0042] The ratio of D50 to D10 (D50 / D10) of the coarse-grained inorganic oxide powder (A) is 1.5 to 3.5,

[0043] The ratio of D90 to D10 (D90 / D10) of the coarse-grained inorganic oxide powder (A) is 4.0 to 7.0.

[0044]

[20] The powder for laminated modeling according to any one of

[12] to

[19] , the shapes of the coarse-grained inorganic oxide powder (A) and the fine-grained inorganic oxide powder (B) are both spherical.

[0045]

[21] The powder for laminated modeling according to any one of

[12] to

[20] , the coarse-grained inorganic oxide powder (A) and the fine-grained inorganic oxide powder (B) are both alumina.

[0046]

[22] The powder for laminated molding according to

[21] has a green density of 2.52 to 2.54 g / cm under a pressure of 98 MPa. 3 .

[0047]

[23] The powder for laminated molding according to any one of

[12] to

[22] is used in the binder jetting method.

[0048]

[24] A sintered body is a sintered body of the powder for laminated molding according to any one of

[12] to

[23] .

[0049]

[25] A method for manufacturing an adhesive jet laminated molded body includes: applying a liquid containing an adhesive to the powder for laminated molding according to any one of

[12] to

[23] to form a three-dimensional laminated molded body.

[0050]

[26] A method for manufacturing a sintered body includes:

[0051] applying a liquid containing an adhesive to the powder for laminated molding according to any one of

[12] to

[23] to form a three-dimensional laminated molded body; and

[0052] sintering the three-dimensional laminated molded body.

[0053]

[27] An alumina powder,

[0054] D10 is 1.0 to 4.0 μm, D50 is 5.5 to 9.0 μm, D90 is 20.0 to 40.0 μm,

[0055] and the volume ratio of particles having a particle size of 16.8 to 60.0 μm is 15.0 to 22.0 vol%.

[0056]

[28] The alumina powder according to

[27] , the volume ratio of particles having a particle size of 2.0 μm or more is 90.0 to 100 vol%.

[0057]

[29] The alumina powder according to

[27] or

[28] ,

[0058] the ratio of D50 to D10 (D50 / D10) is 2.0 to 2.2,

[0059] and the ratio of D90 to D10 (D90 / D10) is 6.0 to 8.0.

[0060]

[30] The alumina powder according to any one of

[27] to

[29] , the BET specific surface area is 0.1 to 10.0 m 2 / g.

[0061]

[31] The alumina powder according to any one of

[27] to

[30] has a spherical shape.

[0062]

[32] The alumina powder according to any one of

[27] to

[31] has a green density of 2.52 to 2.54 g / cm under a pressure of 98 MPa. 3 .

[0063] According to the present disclosure, it is possible to provide a powder for laminated molding, which has an appropriate fluidity that combines good layability capable of forming a uniform powder layer and shape stability capable of maintaining the shape during the period from the application of the binder to the sintering process, and has an appropriate green density capable of allowing the binder to enter between the powder materials and achieving a low shrinkage rate during sintering. Detailed Description of the Invention

[0064] Hereinafter, embodiments of the present invention will be described. Furthermore, the embodiments described below are representative examples of the present invention and are not limited thereto.

[0065] Hereinafter, embodiments of the present invention will be described. Furthermore, the embodiments described below are representative examples of the present invention and are not limited thereto.

[0066] In this specification, regarding a numerical range, when "~" is used, the numerical values at both ends are the upper limit value and the lower limit value, respectively, and are included in the numerical range. When there are multiple upper limit values or lower limit values, numerical ranges can be created according to all combinations of the upper limit value and the lower limit value. Similarly, when there are multiple numerical ranges, other numerical ranges can be created by individually selecting the upper limit value and the lower limit value from these numerical ranges and combining them.

[0067] In this specification, D10, D50, and D90 are the 10% particle size, 50% particle size, and 90% particle size in the volume-based cumulative particle size distribution measured using a particle size distribution measuring device based on the resistance method (Beckman Coulter, Multisizer 4) with an aperture size of 100 μm.

[0068] In this specification, the green density means the density of a compact formed by loading a specimen into a circular mold frame and pressing it under a specified pressure using a commercially available press. The green density is a value as an index of the volume density of a powder layer when a thin layer of powder is formed using a roll or the like.

[0069] In this specification, the angle of repose is a value measured and calculated in accordance with JIS R 9301-2-2:1999 (Alumina powder - Part 2: Physical property measurement method - 2: Angle of repose).

[0070] In this specification, the BET specific surface area is a value measured and calculated according to the "6.2 Flow method (3.5) Single point method" of JIS R 1626:1996 (Method for measuring the specific surface area of fine ceramic powders by the BET method based on gas adsorption). As a pretreatment, the sample is heated to 180 °C, and nitrogen gas is allowed to flow for 20 minutes, and then nitrogen gas is used as the adsorbate for measurement.

[0071] In this specification, the roundness is the average value of the values calculated by the following formula (1) for 5000 particles when the area of the projection image of the particles is denoted as S and the perimeter is denoted as L.

[0072] 4πS / L 2 (1)

[0073] In this specification, the volume ratio of the coarse inorganic oxide powder (A) and the fine inorganic oxide powder (B) is a value calculated as follows based on the charged mass and true density of the materials. The volume VA of the coarse inorganic oxide powder (A) is obtained by dividing the mass of the charged coarse inorganic oxide powder (A) by the true density of the coarse inorganic oxide powder (A). The volume VB of the fine inorganic oxide powder (B) is obtained by dividing the mass of the charged fine inorganic oxide powder (B) by the true density of the fine inorganic oxide powder (B). Using these values, the volume ratio of the coarse inorganic oxide powder (A) is obtained by VA / (VA + VB), and the volume ratio of the fine inorganic oxide powder (B) is obtained by VB / (VA + VB).

[0074] In this specification, the particle size volume ratio is a value calculated by the following formula (2).

[0075] (Volume ratio of coarse inorganic oxide powder (A) × D50 of coarse inorganic oxide powder (A)) / (Volume ratio of fine inorganic oxide powder (B) × D50 of fine inorganic oxide powder (B))(2)

[0076] <Powder for laminated modeling>

[0077] The powder for laminated modeling is an inorganic oxide powder, with D10 being 1.0 to 4.0 μm, D50 being 5.5 to 9.0 μm, and D90 being 20.0 to 40.0 μm. In the powder for laminated modeling, the volume ratio of the particles with a particle size of 16.8 to 60.0 μm is 15.0 to 22.0 vol%. The present inventors have found that in the powder for laminated modeling with D50 being 5.5 to 9.0 μm, the particles with a particle size of 16.8 to 60.0 μm contribute to improving the fluidity and bulk density of the powder for laminated modeling. Thus, it has been found that by controlling the volume ratio of the particles with a particle size of 16.8 to 60.0 μm within a specific range, a good balance between the fluidity and bulk density of the powder material can be achieved.

[0078] The D50 of the powder for laminated modeling is 5.5 μm or more, preferably 6.0 μm or more, and more preferably 6.5 μm or more. The D50 of the powder for laminated modeling is 9.0 μm or less, preferably 8.5 μm or less, and more preferably 8.0 μm or less. The D50 of the powder for laminated modeling is 5.5 to 9.0 μm, preferably 6.0 to 8.5 μm, and more preferably 6.5 to 8.0 μm. If the D50 of the powder for laminated modeling is 5.5 μm or more, the shape stability of the powder layer formed by the powder for laminated modeling is good, and the shrinkage rate during sintering can be reduced. If the D50 of the powder for laminated modeling is 9.0 μm or less, the bulk density and fluidity can be in an appropriate range.

[0079] The D10 of the powder for laminated modeling is 1.0 μm or more, preferably 2.0 μm or more, and more preferably 3.0 μm or more. The D10 of the powder for laminated modeling is 4.0 μm or less, preferably 3.8 μm or less, and more preferably 3.6 μm or less. The D10 of the powder for laminated modeling is 1.0 to 4.0 μm, preferably 2.0 to 3.8 μm, and more preferably 3.0 to 3.6 μm. If the D10 of the powder for laminated modeling is 1.0 μm or more, the shrinkage rate during sintering can be reduced. If the D10 of the powder for laminated modeling is 4.0 μm or less, the bulk density and fluidity can be in an appropriate range.

[0080] The D90 of the powder for laminated modeling is 20.0 μm or more, preferably 20.5 μm or more, and more preferably 21.0 μm or more. The D90 of the powder for laminated modeling is 40.0 μm or less, preferably 30.0 μm or less, and more preferably 25.0 μm or less. The D90 of the powder for laminated modeling is 20.0 to 40.0 μm, preferably 20.5 to 30.0 μm, and more preferably 21.0 to 25.0 μm. If the D90 of the powder for laminated modeling is 20.0 μm or more, the shape stability of the powder layer formed by the powder for laminated modeling is good. If the D90 of the powder for laminated modeling is 40.0 μm or less, the uniformity of the powder layer formed by the powder for laminated modeling is good.

[0081] The volume ratio of particles having a particle size of 16.8 to 60.0 μm in the powder for laminated molding is 15.0% by volume or more, preferably 15.5% by volume or more, and more preferably 16.0% by volume or more. The volume ratio of particles having a particle size of 16.8 to 60.0 μm in the powder for laminated molding is 22.0% by volume or less, preferably 21.0% by volume or less, and more preferably 20.0% by volume or less. The volume ratio of particles having a particle size of 16.8 to 60.0 μm in the powder for laminated molding is 15.0 to 22.0% by volume, preferably 15.5 to 21.0% by volume, and more preferably 16.0 to 20.0% by volume. If the volume ratio of particles having a particle size of 16.8 to 60.0 μm is within the above range, an appropriate fluidity of the powder for laminated molding can be expected. The volume ratio of particles having a particle size of 16.8 to 60.0 μm in the powder for laminated molding is a value determined by measuring with a resistance method particle size distribution measuring device (Beckman Coulter, Multisizer 4) with an aperture size set to 100 μm.

[0082] The volume ratio of particles having a particle size of 2.0 μm or more in the powder for laminated molding is preferably 90.0 to 100% by volume, more preferably 93.0 to 100% by volume, and further preferably 95.0 to 100% by volume. If the volume ratio of particles having a particle size of 2.0 μm or more is 90.0% by volume or more, the shrinkage rate during sintering can be reduced. The volume ratio of particles having a particle size of 2.0 μm or more in the powder for laminated molding is a value determined by using a laser diffraction-scattering type particle size distribution measuring device (MicrotracBEL Corporation, MT3300EXII).

[0083] The ratio of D50 to D10 (D50 / D10) of the powder for laminated molding is preferably 2.0 to 2.2. If D50 / D10 is within the above range, an appropriate fluidity can be expected for the powder for laminated molding, which has both good laying properties capable of forming a uniform powder layer and shape stability capable of maintaining the shape during the period from the application of the binder to the sintering process.

[0084] The ratio of D90 to D10 (D90 / D10) of the powder for laminated modeling is preferably 6.0 or more, more preferably 6.2 or more, and further preferably 6.5 or more. The ratio of D90 to D10 (D90 / D10) of the powder for laminated modeling is preferably 8.0 or less, more preferably 7.5 or less, and further preferably 7.0 or less. The ratio of D90 to D10 (D90 / D10) of the powder for laminated modeling is preferably from 6.0 to 8.0, more preferably from 6.2 to 7.5, and further preferably from 6.5 to 7.0. If D90 / D10 is 8.0 or less, the particle size distribution of the powder converges within a certain range, so fine particles are appropriately arranged around the coarse particles, and the fluidity can be made appropriate. If D90 / D10 is 6.0 or more, fine particles are appropriately arranged between the coarse particles, and the bulk density can be made appropriate.

[0085] The ratio of D90 to D50 (D90 / D50) of the powder for laminated modeling is preferably from 2.8 to 3.6, more preferably from 2.9 to 3.5, and further preferably from 3.2 to 3.4. If D90 / D50 is 3.6 or less, the particle size distribution of the powder converges within a certain range, so fine particles are appropriately arranged around the coarse particles, and the fluidity can be made appropriate. If D90 / D50 is 2.8 or more, fine particles are appropriately arranged between the coarse particles, and the bulk density can be made appropriate.

[0086] The angle of repose of the powder for laminated modeling is preferably from 55 to 58 degrees, more preferably from 56 to 57 degrees. The angle of repose is one of the indexes indicating the fluidity of the powder. If the angle of repose of the powder for laminated modeling is 55 degrees or more, the shape stability of the powder layer formed by the powder for laminated modeling is good. If the angle of repose of the powder for laminated modeling is 58 degrees or less, the powder for laminated modeling can be smoothly supplied to the modeling table and evenly spread.

[0087] The BET specific surface area of the powder for laminated modeling is preferably 0.1 m 2 / g or more, more preferably 0.2 m 2 / g or more. The BET specific surface area of the powder for laminated modeling is preferably 10.0 m 2 / g or less, more preferably 5.0 m 2 / g or less, and further preferably 2.0 m 2 / g or less. The BET specific surface area of the powder for laminated modeling is preferably from 0.1 to 10.0 m 2 / g, more preferably from 0.1 to 5.0 m 2 / g, and further preferably from 0.2 to 2.0 m 2 / g. If the BET specific surface area is 0.1 m 2 / g or more, the shape stability of the powder layer formed by the powder for laminated modeling is good. If the BET specific surface area is 10.0 m 2If it is below / g, the powder for laminated modeling can be smoothly supplied to the modeling table and evenly spread.

[0088] The shape of the powder for laminated modeling is not particularly limited. For example, spherical, ellipsoidal, flaky, amorphous, etc. can be cited. Among them, in order to easily obtain an appropriate bulk density, spherical shape is preferred. From this point of view, the roundness of the powder for laminated modeling is preferably 0.80 or more, more preferably 0.90 or more, and further preferably 0.95 or more. The upper limit of the roundness of the powder for laminated modeling is not particularly limited, but for example, it can be set to 1.00 or 0.99. If the roundness is 0.80 or more, the bulk density of the compression molding can be improved.

[0089] The powder for laminated modeling is preferably at least one selected from silica, alumina, zirconia, and titanium dioxide, more preferably alumina, and further preferably spherical alumina. Alumina has high thermal conductivity, melting point, and hardness, is inexpensive, and is strong in acid and alkali resistance, so it is preferred from this point of view. The volume ratio of alumina in the powder for laminated modeling is preferably 50% by volume or more, more preferably 60% by volume or more, and further preferably 80% by volume or more. The upper limit of the volume ratio of alumina in the powder for laminated modeling is not particularly limited. For example, it can be set to 100% by volume, 98% by volume, or 95% by volume.

[0090] When the powder for laminated modeling is alumina, the bulk density of the compression molding of the powder for laminated modeling under a pressure of 98 MPa is preferably 2.52 - 2.54 g / cm 3 . If the bulk density of the compression molding of the powder for laminated modeling under a pressure of 98 MPa is 2.52 g / cm 3 or more, the dimensional stability during sintering is good. If the bulk density of the compression molding of the powder for laminated modeling under a pressure of 98 MPa is 2.54 g / cm 3 or less, when applying the binder, the binder easily enters between the powder materials, and the strength of the molded body and the sintered body can be sufficient.

[0091] The powder for laminated modeling has good laying property, shape stability of the powder layer, and appropriate bulk density, so it is very suitable for the binder jetting method. The powder for laminated modeling can also be applied to the powder bed melting method of irradiating a laser or an electron beam on a powder bed covered with a powder material to selectively melt it for modeling, and other powder lamination modeling methods.

[0092] The powder for laminated modeling can also be applied to other uses other than the laminated modeling method. For example, the powder for laminated modeling can be used as a filler in coatings such as heat dissipation coatings, heat insulation coatings, and wear-resistant coatings, a filler in a thermally conductive resin composition having adhesiveness, and a filler in a thermally conductive coating material having a function of curing in the atmosphere.

[0093] The inorganic oxide powder of one embodiment is an alumina powder having a D10 of 1.0 to 4.0 μm, a D50 of 5.5 to 9.0 μm, a D90 of 20.0 to 40.0 μm, and the volume ratio of particles having a particle size of 16.8 to 60.0 μm is 15.0 to 22.0 vol%.

[0094] <Manufacturing method of powder for laminated modeling>

[0095] The powder for laminated modeling can be manufactured, for example, by mixing a plurality of inorganic oxide powders having different particle size distributions so that the particle size distribution of the powder for laminated modeling falls within a specified range. The particle size distribution of the powder for laminated modeling can also be adjusted by sieving or the like. The particle size distribution of the powder for laminated modeling can be adjusted to an appropriate range by selecting the types (particle size distributions) and blending amounts of the inorganic oxide powders to be blended. The mixing method of the materials is not particularly limited, and examples thereof include a method of dry-mixing or wet-mixing the materials. The mixing can be performed manually or using a blender.

[0096] As a more specific manufacturing method of the powder for laminated modeling, for example, a method of mixing the following coarse-grained inorganic oxide powder (A) and fine-grained inorganic oxide powder (B) having a D50 smaller than that of the coarse-grained inorganic oxide powder (A) can be cited.

[0097] [Coarse-grained inorganic oxide powder (A)]

[0098] The D50 of the coarse-grained inorganic oxide powder (A) used is preferably 9.0 to 25.0 μm, more preferably 12.0 to 20.0 μm, and further preferably 14.0 to 18.0 μm. The D10 of the coarse-grained inorganic oxide powder (A) is preferably 1.0 to 8.0 μm, more preferably 2.0 to 7.5 μm, and further preferably 3.0 to 7.0 μm. The D90 of the coarse-grained inorganic oxide powder (A) is preferably 28.0 to 40.0 μm, more preferably 28.5 to 38.0 μm, and further preferably 29.0 to 36.0 μm.

[0099] The ratio (D50 / D10) of D50 to D10 of the coarse inorganic oxide powder (A) is preferably 1.5 to 3.5, more preferably 1.7 to 3.2, and still more preferably 2.0 to 3.0. The ratio (D90 / D10) of D90 to D10 of the coarse inorganic oxide powder (A) is preferably 3.5 to 9.0, more preferably 4.0 to 7.0, and still more preferably 4.5 to 6.0. The ratio (D90 / D50) of D90 to D50 of the coarse inorganic oxide powder (A) is preferably 1.7 to 2.3, more preferably 1.8 to 2.2, and still more preferably 1.9 to 2.0.

[0100] The shape of the coarse inorganic oxide powder (A) is not particularly limited. For example, spherical, ellipsoidal, scaly, amorphous, etc. may be mentioned. Among them, in order to easily obtain an appropriate bulk density, a spherical shape is preferred.

[0101] The coarse inorganic oxide powder (A) is preferably at least one selected from silica, alumina, zirconia, and titanium dioxide, more preferably alumina, and still more preferably spherical alumina. The volume ratio of alumina in the coarse inorganic oxide powder (A) is preferably 50% by volume or more, more preferably 60% by volume or more, and still more preferably 80% by volume or more. The upper limit of the volume ratio of alumina in the coarse inorganic oxide powder (A) is not particularly limited. For example, it may be set to 100% by volume, 98% by volume, or 95% by volume.

[0102] [Fine inorganic oxide powder (B)]

[0103] The D50 of the fine inorganic oxide powder (B) is smaller than the D50 of the coarse inorganic oxide powder (A). The D50 of the fine inorganic oxide powder (B) used is preferably 5.0 to 8.0 μm, more preferably 5.5 to 7.8 μm, and still more preferably 6.0 to 7.5 μm. The D10 of the fine inorganic oxide powder (B) is preferably 1.0 to 4.0 μm, more preferably 2.0 to 3.8 μm, and still more preferably 2.5 to 3.5 μm. The D90 of the fine inorganic oxide powder (B) is preferably 9.0 to 25.0 μm, more preferably 12.0 to 24.0 μm, and still more preferably 14.0 to 23.0 μm.

[0104] The ratio (D50 / D10) of D50 to D10 of the fine inorganic oxide powder (B) is preferably 1.5 to 5.0, more preferably 1.7 to 4.0, and still more preferably 1.8 to 3.0. The ratio (D90 / D10) of D90 to D10 of the fine inorganic oxide powder (B) is preferably 3.5 to 9.0, more preferably 4.5 to 8.0, and still more preferably 5.5 to 7.0. The ratio (D90 / D50) of D90 to D50 of the fine inorganic oxide powder (B) is preferably 2.5 to 3.5, more preferably 2.8 to 3.2, and still more preferably 2.7 to 2.9.

[0105] The shape of the fine inorganic oxide powder (B) is not particularly limited. For example, spherical, ellipsoidal, scaly, amorphous, etc. may be mentioned. Among them, in order to easily obtain an appropriate bulk density, spherical shape is preferred.

[0106] The fine inorganic oxide powder (B) is preferably at least one selected from silica, alumina, zirconia, and titanium dioxide, more preferably alumina, and still more preferably spherical alumina. The volume ratio of alumina in the fine inorganic oxide powder (B) is preferably 50% by volume or more, more preferably 60% by volume or more, and still more preferably 80% by volume or more. The upper limit of the volume ratio of alumina in the fine inorganic oxide powder (B) is not particularly limited. For example, it may be set to 100% by volume, 98% by volume, or 95% by volume.

[0107] The volume ratio of the coarse inorganic oxide powder (A) relative to the total volume of the coarse inorganic oxide powder (A) and the fine inorganic oxide powder (B) is selected in such a way that the particle size distribution of the powder for laminated molding becomes an appropriate range. For example, it may be set to 9.5 to 29.0% by volume.

[0108] <Powder for laminated molding>

[0109] In the powder laminated molding method of spreading a powder material using a roll or the like, the bulk molding density of the material is important. Compared with the inorganic oxide powder having a larger D50, the inorganic oxide powder having a smaller D50 tends to have a lower bulk density and a lower fluidity. The present inventors have found that by mixing a small amount of the coarse inorganic oxide powder (A) with the fine inorganic oxide powder (B) having a D50 smaller than that of the coarse inorganic oxide powder (A), a good balance between the fluidity and the bulk density of the powder material can be achieved. This is completely different from the conventional design concept of powder materials that fill fine particles into the gaps of coarse particles to increase the bulk density.

[0110] The powder for laminated molding preferably has a D50 (D A 50) of the coarse inorganic oxide powder (A) and a D50 (D B50) Satisfy D A 50 - D B 50 ≥ 3.5 μm. If within this range, the advantages of the particles of the coarse inorganic oxide powder (A) and the fine inorganic oxide powder (B) are both effective, and a powder with a good balance between fluidity and bulk density can be obtained. From the same perspective, D is more preferably A 50 - D B 50 ≥ 5.5 μm, and D is further preferably A 50 - D B 50 ≥ 7.5 μm. D A 50 - D B The upper limit of 50 can be set to 12.0 μm, 15.0 μm, or 19.0 μm.

[0111] In the first embodiment, the powder for laminated molding contains a coarse inorganic oxide powder (A) with a D50 of 9.0 to 25.0 μm and a fine inorganic oxide powder (B) with a D50 smaller than that of the coarse inorganic oxide powder (A). With respect to the total volume of the coarse inorganic oxide powder (A) and the fine inorganic oxide powder (B), the volume ratio of the coarse inorganic oxide powder (A) is 9.5 to 29.0 vol%.

[0112] In this embodiment, with respect to the total volume of the coarse inorganic oxide powder (A) and the fine inorganic oxide powder (B), the volume ratio of the coarse inorganic oxide powder (A) is 9.5 to 29.0 vol%, preferably 10.5 to 20.0 vol%, and more preferably 11.6 to 15.0 vol%. With respect to the total volume of the coarse inorganic oxide powder (A) and the fine inorganic oxide powder (B), the volume ratio of the coarse inorganic oxide powder (A) is 9.5 vol% or more, preferably 10.5 vol% or more, and more preferably 11.6 vol% or more. With respect to the total volume of the coarse inorganic oxide powder (A) and the fine inorganic oxide powder (B), the volume ratio of the coarse inorganic oxide powder (A) is 29.0 vol% or less, preferably 20.0 vol% or less, and more preferably 15.0 vol% or less. If the above volume ratio is 9.5 vol% or more, the bulk density can be increased to an appropriate range for the powder for laminated molding. If the above volume ratio is 29.0 vol% or less, the fluidity can be suppressed to an appropriate range for the powder for laminated molding.

[0113] In this embodiment, the particle size volume ratio of the coarse inorganic oxide powder (A) to the fine inorganic oxide powder (B) is preferably from 0.26 to 1.15, more preferably from 0.27 to 0.74, and still more preferably from 0.29 to 0.32. The particle size volume ratio of the coarse inorganic oxide powder (A) to the fine inorganic oxide powder (B) is preferably 0.26 or more, more preferably 0.27 or more, and still more preferably 0.29 or more. The particle size volume ratio of the coarse inorganic oxide powder (A) to the fine inorganic oxide powder (B) is preferably 1.15 or less, more preferably 0.74 or less, and still more preferably 0.32 or less. If the above particle size volume ratio is 0.26 or more, the bulk density can be increased to be within a suitable range for the powder for laminated molding. If the particle size volume ratio is 1.15 or less, the fluidity can be suppressed to be within a suitable range for the powder for laminated molding.

[0114] In the second embodiment, the powder for laminated molding contains a coarse inorganic oxide powder (A) having a D50 of 9.0 to 25.0 μm and a fine inorganic oxide powder (B) having a D50 smaller than that of the coarse inorganic oxide powder (A), and the particle size volume ratio of the coarse inorganic oxide powder (A) to the fine inorganic oxide powder (B) is 0.26 to 1.15.

[0115] In this embodiment, the particle size volume ratio of the coarse inorganic oxide powder (A) to the fine inorganic oxide powder (B) is 0.26 to 1.15, preferably 0.27 to 0.74, more preferably 0.29 to 0.32. The particle size volume ratio of the coarse inorganic oxide powder (A) to the fine inorganic oxide powder (B) is 0.26 or more, preferably 0.27 or more, more preferably 0.29 or more. The particle size volume ratio of the coarse inorganic oxide powder (A) to the fine inorganic oxide powder (B) is 1.15 or less, preferably 0.74 or less, more preferably 0.32 or less. If the above particle size volume ratio is 0.26 or more, the bulk density can be increased to be within a suitable range for the powder for laminated molding. If the particle size volume ratio is 1.15 or less, the fluidity can be suppressed to be within a suitable range for the powder for laminated molding.

[0116] In this embodiment, the volume ratio of the coarse inorganic oxide powder (A) to the total volume of the coarse inorganic oxide powder (A) and the fine inorganic oxide powder (B) is preferably 9.5 to 29.0% by volume, more preferably 10.5 to 20.0% by volume, and still more preferably 12.0 to 15.0% by volume. The volume ratio of the coarse inorganic oxide powder (A) to the total volume of the coarse inorganic oxide powder (A) and the fine inorganic oxide powder (B) is preferably 9.5% by volume or more, more preferably 10.5% by volume or more, and further preferably 12.0% by volume or more. The volume ratio of the coarse inorganic oxide powder (A) to the total volume of the coarse inorganic oxide powder (A) and the fine inorganic oxide powder (B) is preferably 29.0% by volume or less, more preferably 20.0% by volume or less, and further preferably 15.0% by volume or less. If the above volume ratio is 9.5% by volume or more, the bulk density can be increased to be within an appropriate range for the powder for laminated molding. If the volume ratio is 29.0% by volume or less, the fluidity can be suppressed to be within an appropriate range for the powder for laminated molding.

[0117] The D50 of the powder for laminated molding is preferably 5.5 to 9.0 μm, more preferably 6.0 to 8.5 μm, and still more preferably 6.5 to 8.0 μm. If the D50 of the powder for laminated molding is 5.5 μm or more, the shape stability of the powder layer formed from the powder for laminated molding is better, and the shrinkage rate during sintering can be reduced. If the D50 of the powder for laminated molding is 9.0 μm or less, the bulk density and fluidity can be within an appropriate range.

[0118] The D10 of the powder for laminated molding is preferably 1.0 to 4.0 μm, more preferably 2.0 to 3.8 μm, and still more preferably 3.0 to 3.6 μm. If the D10 of the powder for laminated molding is 1.0 μm or more, the shrinkage rate during sintering can be reduced. If the D10 of the powder for laminated molding is 4.0 μm or less, the bulk density and fluidity can be within an appropriate range.

[0119] The D90 of the powder for laminated molding is preferably 20.0 to 40.0 μm, more preferably 20.5 to 30.0 μm, and still more preferably 21.0 to 25.0 μm. If the D90 of the powder for laminated molding is 20.0 μm or more, the shape stability of the powder layer formed from the powder for laminated molding is better. If the D90 of the powder for laminated molding is 40.0 μm or less, the uniformity of the powder layer formed from the powder for laminated molding is better.

[0120] The volume ratio of particles having a particle size of 16.8 to 60.0 μm in the powder for laminated modeling is preferably 15.0 to 26.0% by volume, more preferably 15.0 to 22.0% by volume, and further preferably 16.0 to 20.0% by volume. If the volume ratio of particles having a particle size of 16.8 to 60.0 μm is within the above range, appropriate fluidity of the powder material can be expected. The volume ratio of particles having a particle size of 16.8 to 60.0 μm in the powder for laminated modeling is a value determined by measuring with a resistance method particle size distribution measuring device (Beckman Coulter, Multisizer4) with a pore size of 100 μm.

[0121] The volume ratio of particles having a particle size of 2.0 μm or more in the powder for laminated modeling is preferably 90.0 to 100% by volume, more preferably 93.0 to 100% by volume, and further preferably 95.0 to 100% by volume. If the volume ratio of particles having a particle size of 2.0 μm or more is 90.0% by volume or more, the shrinkage rate during sintering can be reduced. The volume ratio of particles having a particle size of 2.0 μm or more in the powder for laminated modeling is a value determined by using a laser diffraction-scattering type particle size distribution measuring device (MicrotracBEL Corporation, MT3300EXII).

[0122] The ratio of D50 to D10 (D50 / D10) of the powder for laminated modeling is preferably 2.0 to 2.2. If D50 / D10 is within the above range, appropriate fluidity can be expected for the powder for laminated modeling, which has good spreadability capable of forming a uniform powder layer and shape stability capable of maintaining the shape during the period from the application of the binder to the sintering process.

[0123] The ratio of D90 to D10 (D90 / D10) of the powder for laminated modeling is preferably 6.0 to 8.0, more preferably 6.2 to 7.5, and further preferably 6.5 to 7.0. If D90 / D10 is 8.0 or less, the particle size distribution of the powder converges within a certain range, so fine particles are appropriately arranged around the coarse particles, and the fluidity can be made appropriate. If D90 / D10 is 6.0 or more, fine particles are appropriately arranged between the coarse particles, and the bulk density can be made appropriate.

[0124] The ratio of D90 to D50 (D90 / D50) of the powder for laminated modeling is preferably 2.8 to 3.6, more preferably 2.9 to 3.5, and further preferably 3.2 to 3.4. If D90 / D50 is 3.6 or less, the particle size distribution of the powder converges within a certain range, and fine particles are appropriately arranged around the coarse particles, and the fluidity can be made appropriate. If D90 / D50 is 2.8 or more, fine particles are appropriately arranged between the coarse particles, and the bulk density can be made appropriate.

[0125] The angle of repose of the powder for laminated molding is preferably 55 to 58 degrees, more preferably 56 to 57 degrees. The angle of repose is one of the indexes indicating the fluidity of the powder. If the angle of repose of the powder for laminated molding is 55 degrees or more, the shape stability of the powder layer formed by the powder for laminated molding is good. If the angle of repose of the powder for laminated molding is 58 degrees or less, the powder for laminated molding can be smoothly supplied to the molding table and evenly spread.

[0126] The BET specific surface area of the powder for laminated molding is preferably 0.1 to 10.0 m 2 / g, more preferably 0.1 to 5.0 m 2 / g, and further preferably 0.2 to 2.0 m 2 / g. If the BET specific surface area is 0.1 m 2 / g or more, the shape stability of the powder layer formed by the powder for laminated molding is good. If the BET specific surface area is 10.0 m 2 / g or less, the powder for laminated molding can be smoothly supplied to the molding table and evenly spread.

[0127] The shape of the powder for laminated molding is not particularly limited. For example, spherical, ellipsoidal, scaly, amorphous, etc. can be cited. Among them, in order to easily obtain an appropriate bulk density, spherical shape is preferred. From this point of view, the roundness of the powder for laminated molding is preferably 0.80 or more, more preferably 0.90 or more, and further preferably 0.95 or more. The upper limit of the roundness of the powder for laminated molding is not particularly limited, but can be set to 1.00 or 0.99, for example. If the roundness is 0.80 or more, the bulk density of the compression molding can be improved.

[0128] The powder for laminated molding is preferably at least one selected from silica, alumina, zirconia, and titanium dioxide, more preferably alumina, and further preferably spherical alumina. Alumina has high thermal conductivity, melting point and hardness, is inexpensive, and is strong in acid and alkali resistance, so it is preferred from this point of view. The volume ratio of alumina in the powder for laminated molding is preferably 50% by volume or more, more preferably 60% by volume or more, and further preferably 80% by volume or more. The upper limit of the volume ratio of alumina in the powder for laminated molding is not particularly limited, and can be set to 100% by volume, 98% by volume, or 95% by volume, for example.

[0129] When the powder for laminated molding is alumina, the bulk density of the compression molding of the powder for laminated molding under a pressure of 98 MPa is preferably 2.52 to 2.54 g / cm 3 . If the bulk density of the compression molding of the powder for laminated molding under a pressure of 98 MPa is 2.52 g / cm 3Above, the dimensional stability during sintering is good. If the green density of the powder for laminated modeling under a pressure of 98 MPa is 2.54 g / cm 3 Below, when applying the binder, the binder easily enters between the powder materials, enabling sufficient strength of the molded body and the sintered body.

[0130] The powder for laminated modeling is very suitable for the binder jetting method because of its good spreadability, shape stability of the powder layer, and appropriate green density. The powder for laminated modeling can also be applied to the powder bed melting method in which a powder bed filled with powder materials is irradiated with a laser or an electron beam to selectively melt it for modeling, and other powder lamination modeling methods.

[0131] The powder for laminated modeling can also be applied to other uses other than the laminated modeling method. The powder for laminated modeling can be used, for example, as a filler in coatings such as heat dissipation coatings, heat insulation coatings, and wear-resistant coatings, a filler in a thermally conductive resin composition having adhesiveness, and a filler in a thermally conductive coating material having a function of curing in the atmosphere.

[0132] [Coarse-grained inorganic oxide powder (A)]

[0133] The D50 of the coarse-grained inorganic oxide powder (A) is 9.0 μm or more, preferably 12.0 μm or more, more preferably 14.0 μm or more. The D50 of the coarse-grained inorganic oxide powder (A) is 25.0 μm or less, preferably 20.0 μm or less, more preferably 18.0 μm or less. The D50 of the coarse-grained inorganic oxide powder (A) is 9.0 to 25.0 μm, preferably 12.0 to 20.0 μm, more preferably 14.0 to 18.0 μm. If the D50 of the coarse-grained inorganic oxide powder (A) is 9.0 μm or more, it is easy to fill the powder for laminated modeling at a high density. If the D50 of the coarse-grained inorganic oxide powder (A) is 25.0 μm or less, the angle of repose of the powder for laminated modeling can be controlled within an appropriate range.

[0134] The D10 of the coarse-grained inorganic oxide powder (A) is preferably 1.0 to 8.0 μm, more preferably 2.0 to 7.5 μm, further preferably 3.0 to 7.0 μm. If the D10 of the coarse-grained inorganic oxide powder (A) is 1.0 μm or more, the shrinkage rate during sintering can be reduced. If the D10 of the coarse-grained inorganic oxide powder (A) is 8.0 μm or less, moderate fluidity of the powder material can be expected.

[0135] The D90 of the coarse inorganic oxide powder (A) is preferably 28.0 to 40.0 μm, more preferably 28.5 to 38.0 μm, and further preferably 29.0 to 36.0 μm. If the D90 of the coarse inorganic oxide powder (A) is 28.0 μm or more, the density of the molded body formed from the powder for laminated molding can be increased, and the shape stability is better. If the D90 of the coarse inorganic oxide powder (A) is 40.0 μm or less, the uniformity of the powder layer formed from the powder for laminated molding is better.

[0136] The ratio of D50 to D10 (D50 / D10) of the coarse inorganic oxide powder (A) is preferably 1.5 or more, more preferably 1.7 or more, and further preferably 2.0 or more. The ratio of D50 to D10 (D50 / D10) of the coarse inorganic oxide powder (A) is preferably 3.5 or less, more preferably 3.2 or less, and further preferably 3.0 or less. The ratio of D50 to D10 (D50 / D10) of the coarse inorganic oxide powder (A) is preferably 1.5 to 3.5, more preferably 1.7 to 3.2, and further preferably 2.0 to 3.0. If D50 / D10 is within the above range, an increase in the volume density of the compression molding can be expected.

[0137] The ratio of D90 to D10 (D90 / D10) of the coarse inorganic oxide powder (A) is preferably 4.0 or more, more preferably 4.5 or more, and further preferably 5.0 or more. The ratio of D90 to D10 (D90 / D10) of the coarse inorganic oxide powder (A) is preferably 7.0 or less, more preferably 6.0 or less, and further preferably 5.5 or less. The ratio of D90 to D10 (D90 / D10) of the coarse inorganic oxide powder (A) is preferably 4.0 to 7.0, more preferably 4.5 to 6.0, and further preferably 5.0 to 5.5. If D90 / D10 is within the above range, the particle size distribution converges within a certain range, so it is easy to use as the base material of the powder for laminated molding, and the volume density and fluidity can be improved with good balance.

[0138] The ratio of D90 to D50 (D90 / D50) of the coarse inorganic oxide powder (A) is preferably 1.7 to 2.3, more preferably 1.8 to 2.2, and further preferably 1.9 to 2.0. If D90 / D50 is within the above range, the fluidity of the powder for laminated molding can be kept within an appropriate range.

[0139] The shape of the coarse inorganic oxide powder (A) is not particularly limited. For example, spherical, ellipsoidal, scaly, amorphous, etc. can be cited. Among them, spherical is preferred in order to easily obtain an appropriate volume density.

[0140] The coarse inorganic oxide powder (A) is preferably at least one selected from silica, alumina, zirconia, and titanium dioxide, more preferably alumina, and further preferably spherical alumina. The volume ratio of alumina in the coarse inorganic oxide powder (A) is preferably 50% by volume or more, more preferably 60% by volume or more, and further preferably 80% by volume or more. The upper limit of the volume ratio of alumina in the coarse inorganic oxide powder (A) is not particularly limited, and can be set to, for example, 100% by volume, 98% by volume, or 95% by volume.

[0141] [Fine inorganic oxide powder (B)]

[0142] The D50 of the fine inorganic oxide powder (B) is smaller than the D50 of the coarse inorganic oxide powder (A). The D50 of the fine inorganic oxide powder (B) is preferably 5.0 μm or more, more preferably 5.5 μm or more, and further preferably 6.0 μm or more. The D50 of the fine inorganic oxide powder (B) is preferably 8.0 μm or less, more preferably 7.8 μm or less, and further preferably 7.5 μm or less. The D50 of the fine inorganic oxide powder (B) is preferably 5.0 to 8.0 μm, more preferably 5.5 to 7.8 μm, and further preferably 6.0 to 7.5 μm. If the D50 of the fine inorganic oxide powder (B) is 5.0 μm or more, it is easy to fill the powder for laminated molding with high density. If the D50 of the fine inorganic oxide powder (B) is 8.0 μm or less, the angle of repose of the laminated molding powder can be increased and the fluidity can be suppressed.

[0143] The D10 of the fine inorganic oxide powder (B) is preferably 1.0 to 4.0 μm, more preferably 2.0 to 3.8 μm, and further preferably 2.5 to 3.5 μm. If the D10 of the fine inorganic oxide powder (B) is within the above range, it can be expected that the fine inorganic oxide powder (B) will act as a bearing (bearing effect) and keep the fluidity within an appropriate range.

[0144] The D90 of the fine inorganic oxide powder (B) is preferably 9.0 to 25.0 μm, more preferably 12.0 to 24.0 μm, and further preferably 14.0 to 23.0 μm. If the D90 of the fine inorganic oxide powder (B) is within the above range, an appropriate fluidity of the powder for laminated molding can be expected.

[0145] The ratio of D50 to D10 (D50 / D10) of the fine inorganic oxide powder (B) is preferably 1.5 to 5.0, more preferably 1.7 to 4.0, and further preferably 1.8 to 3.0. If D50 / D10 is within the above range, the effect of suppressing the aggregation of the fine inorganic oxide powders (B) can be expected, and the bulk density of the powder for laminated molding can be increased.

[0146] The ratio (D90 / D10) of D90 to D10 of the fine inorganic oxide powder (B) is preferably from 3.5 to 9.0, more preferably from 4.5 to 8.0, and still more preferably from 5.5 to 7.0. If D90 / D10 is within the above range, the particle size distribution converges within a certain range, so it is easy to be used as the base material of the powder for laminated modeling, and the bulk density and fluidity can be improved with good balance.

[0147] The ratio (D90 / D50) of D90 to D50 of the fine inorganic oxide powder (B) is preferably from 2.5 to 3.5, more preferably from 2.8 to 3.2, and still more preferably from 2.7 to 2.9. If D90 / D50 is within the above range, the fluidity of the powder for laminated modeling can be within an appropriate range.

[0148] The shape of the fine inorganic oxide powder (B) is not particularly limited. For example, spherical, ellipsoidal, scaly, amorphous, etc. can be cited. Among them, in order to easily obtain an appropriate bulk density, a spherical shape is preferred.

[0149] The fine inorganic oxide powder (B) is preferably at least one selected from silica, alumina, zirconia, and titanium dioxide, more preferably alumina, and still more preferably spherical alumina. The volume ratio of alumina in the fine inorganic oxide powder (B) is preferably 50% by volume or more, more preferably 60% by volume or more, and still more preferably 80% by volume or more. The upper limit of the volume ratio of alumina in the fine inorganic oxide powder (B) is not particularly limited. For example, it can be set to 100% by volume, 98% by volume, or 95% by volume.

[0150] <Manufacturing method of powder for laminated modeling>

[0151] The powder for laminated modeling can be manufactured by mixing the coarse inorganic oxide powder (A) and the fine inorganic oxide powder (B). The mixing method of the materials is not particularly limited. For example, methods such as dry mixing or wet mixing of the coarse inorganic oxide powder (A) and the fine inorganic oxide powder (B) can be cited. The mixing can be carried out manually or using a mixer.

[0152] <Manufacturing method of three-dimensional laminated modeling body>

[0153] The three-dimensional laminated modeling body can be manufactured by processing the powder for laminated modeling using a known powder laminated modeling method. As the powder laminated modeling method, for example, an adhesive jetting method and a powder bed melting method can be cited. The powder laminated modeling method generally includes the following steps.

[0154] (1) A step of supplying the powder for laminated modeling to the modeling table of the powder laminated modeling device;

[0155] (2) A step of uniformly and thinly spreading the supplied powder for laminated modeling using a roller or the like to form a thin layer of the powder for laminated modeling;

[0156] (3) A step of irradiating a laser or an electron beam on the formed thin layer of the powder for laminated modeling, or applying a liquid containing a binder to bond the powder for laminated modeling;

[0157] (4) A step of supplying a new powder for laminated modeling onto the solidified powder for laminated modeling.

[0158] Thereafter, by repeatedly performing steps (2) to (4), a target three-dimensional laminated modeling body can be manufactured.

[0159] As a method of applying a liquid containing a binder, a method of discharging a liquid containing a binder is preferred. As a method of discharging a liquid containing a binder, there is no particular limitation, and for example, a dispenser method, a spray method, and an inkjet method can be cited. Among them, from the viewpoint of good quantitative property of droplets and the ability to coat a large area, the inkjet method is preferred.

[0160] In the case of using the inkjet method, a liquid containing a binder can be applied using an inkjet head having a nozzle for discharging the liquid. As the inkjet head, an inkjet head in a known inkjet printer can be suitably used, and for example, an industrial inkjet RICOH MH / GH series (Ricoh Company, Ltd.) can be cited.

[0161] There is no particular limitation on the binder, and known binders such as polyvinylpyrrolidone, polyvinyl alcohol, polyethylene glycol, polyvinyl butyral, acrylic resins, and polyamides can be used. The binder can be used after adjusting the viscosity with an appropriate solvent.

[0162] <Method for manufacturing a sintered body>

[0163] A sintered body can be manufactured by sintering a three-dimensional laminated modeling body using a known sintering method. It is preferred to perform a debinding treatment before the sintering treatment. The following illustrates a specific method for manufacturing a sintered body.

[0164] Place the three-dimensional laminated molded body in a sintering furnace and raise the temperature in the furnace to the degreasing temperature. The degreasing temperature can be appropriately set within the range of, for example, 500 to 700 °C. Thereafter, maintain the temperature in the furnace at the degreasing temperature for 0.5 to 4 hours to burn the organic components (degreasing treatment). The degreasing time can be set according to the type of binder and the ratio of organic components in the three-dimensional laminated molded body. Next, raise the temperature in the furnace to the sintering temperature. The sintering temperature can be appropriately set within the range of, for example, 900 to 1300 °C. Thereafter, maintain the temperature in the furnace at the sintering temperature for 1 to 7 hours to sinter the three-dimensional laminated molded body, thereby obtaining a sintered body (sintering treatment). The sintering temperature and sintering time can be set according to the type of inorganic oxide powder.

[0165] Examples

[0166] Hereinafter, the present invention will be described more specifically by way of examples and comparative examples, but the present invention is not limited to the following examples.

[0167] <Materials Used>

[0168] Coarse inorganic oxide powder (A): Spherical alumina (Alnavis (trademark) / CB manufactured by Showa Denko K.K.): True density 3.95 g / m 3

[0169] Fine inorganic oxide powder (B): Spherical alumina (Alnavis (trademark) / CB manufactured by Showa Denko K.K.): True density 3.95 g / m 3

[0170] <Evaluation Method>

[0171] (Bulk density)

[0172] The bulk density is evaluated using the bulk density of the compacted body under a pressure of 98 MPa. Specifically, the sample was placed in a circular mold (inner diameter 30 mm), and a compacted body was produced using a commercially available press at a pressure of 98 MPa. The density of the obtained compacted body was determined as the bulk density of the compacted body under a pressure of 98 MPa. If the bulk density of the compacted body is 2.52 g / cm 3 or more, the density of the three-dimensional laminated molded body is high, so the shrinkage rate during sintering is low, which is excellent. If the bulk density of the compacted body is 2.54 g / cm 3 or less, when applying the binder, the binder can enter between the powder materials, which is excellent. That is, when the bulk density of the compacted body is 2.52 to 2.54 g / cm 3 the bulk density is evaluated as good.

[0173] (Roundness)

[0174] The measurement of the area S and the perimeter L was carried out using an FPIA-3000 manufactured by Malvern Panalytical. As a pretreatment, due to the measurement range of the device, approximately 10 g of the sample was placed in a metal sieve with a diameter of 200 mm (sieve hole size 25 μm), and particles larger than 25 μm were removed by spraying water. The sample passing through the sieve was transferred to a plastic container and used as the measurement sample. The measurement conditions were set to the LPF / HPF standard (20x lens) and bright field, and a particle sheath reagent manufactured by Malvern Panalytical was used as the measurement solvent. 2 g of the measurement sample was weighed into a 50 mL beaker in such a way that the number of effective analysis particles became 5000, and it was put into the device with pure water for measurement. As data processing after the measurement, data in the case where there were multiple particles on one screen was deleted, and the average roundness was calculated.

[0175] (Flowability)

[0176] The flowability was evaluated using the angle of repose. If the angle of repose is 55° or more, the shape stability (flowability) that can maintain the shape during the period from the application of the binder to the sintering treatment is excellent. If it is 58° or less, the laying property (flowability) that can be smoothly supplied to the molding table and evenly spread is excellent. That is, when the angle of repose is 55 to 58°, the flowability is evaluated as good.

[0177] [Example 1]

[0178] A coarse-grained inorganic oxide powder (A) and a fine-grained inorganic oxide powder (B) having the particle sizes and particle size ratios shown in Table 1 were mixed using a rocking mixer so that the volume ratio of the coarse-grained inorganic oxide powder (A) with respect to the total volume of the coarse-grained inorganic oxide powder (A) and the fine-grained inorganic oxide powder (B) was 11.1 vol%, and a powder for laminated molding was obtained. The particle size distribution, BET specific surface area, roundness, flowability (angle of repose), and green density of the obtained powder for laminated molding were evaluated. The results are shown in Table 2.

[0179] [Examples 2 to 6, Comparative Examples 1 to 16]

[0180] The coarse-grained inorganic oxide powder (A) and the fine-grained inorganic oxide powder (B), and the volume ratio of the coarse-grained inorganic oxide powder (A) with respect to the total volume of the coarse-grained inorganic oxide powder (A) and the fine-grained inorganic oxide powder (B) were set as shown in Table 1. Otherwise, a powder for laminated molding was obtained in the same manner as in Example 1. The particle size distribution, BET specific surface area, roundness, flowability (angle of repose), and green density of the obtained powder for laminated molding were evaluated. The results are shown in Table 2. Furthermore, those not evaluated are recorded as "-".

[0181]

[0182]

[0183]

[0184]

[0185] Examples 1 to 6 have a moderate flowability because the angle of repose is in the range of 55 to 58 degrees. Therefore, it is considered that in the case of using the binder jetting method, a uniform powder layer can be formed when forming a thin layer of the powder for laminated modeling, and the shape can be maintained during the period from the application of the binder to the sintering process. In addition, in Examples 1 to 6, since the green compact volume density is in the range of 2.52 to 2.54 g / cm 3 , having a moderate green compact volume density, it is considered that in the case of using the binder jetting method, the binder can enter between the powder materials, and a low shrinkage rate during sintering can be achieved.

[0186] Industrial Applicability

[0187] By using the powder for laminated modeling according to one embodiment, in the laminated modeling method (binder jetting method) of jetting and curing a liquid binder onto a spread powder material, a molded body with few voids can be produced, and an effect of reducing the heating shrinkage during the sintering process of the molded body can be expected.

Claims

1. A powder for laminated modeling, which is an inorganic oxide powder, with D10 being 1.0 - 4.0 μm, D50 being 5.5 - 9.0 μm, and D90 being 20.0 - 40.0 μm, and the volume ratio of particles with a particle size of 16.8 - 60.0 μm being 15.0 - 22.0 vol%.

2. The powder for laminated modeling according to claim 1, wherein the volume ratio of particles with a particle size of 2.0 μm or more is 90.0 - 100 vol%.

3. The powder for laminated modeling according to claim 1, the ratio of D50 to D10, i.e., D50 / D10, being 2.0 - 2.2, and the ratio of D90 to D10, i.e., D90 / D10, being 6.0 - 8.

0.

4. The powder for laminated modeling according to any one of claims 1 to 3 has a BET specific surface area of 0.1 to 10.0 m 2 / g.

5. The powder for laminated modeling according to any one of claims 1 - 3, having a spherical shape.

6. The powder for laminated modeling according to any one of claims 1 - 3, which is alumina.

7. The powder for laminated modeling according to claim 6 has a compacted bulk density of 2.52 to 2.54 g / cm under a pressure of 98 MPa 3 .

8. The powder for laminated modeling according to any one of claims 1 - 3, which is used in the binder jetting method.

9. A sintered body, which is a sintered body of the powder for laminated modeling according to any one of claims 1 - 3.

10. A method for manufacturing an adhesive jet laminated modeling body, comprising: applying a liquid containing an adhesive to the powder for laminated modeling according to any one of claims 1 - 3 to form a three - dimensional laminated modeling body.

11. A method for manufacturing a sintered body, comprising: applying a liquid containing an adhesive to the powder for laminated modeling according to any one of claims 1 - 3 to form a three - dimensional laminated modeling body; and sintering the three - dimensional laminated modeling body.

12. An alumina powder, with D10 being 1.0 - 4.0 μm, D50 being 5.5 - 9.0 μm, and D90 being 20.0 - 40.0 μm, and the volume ratio of particles with a particle size of 16.8 - 60.0 μm being 15.0 - 22.0 vol%.

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