JP6967884B2 - Laminated model coating slurry and three-dimensional shape - Google Patents

Description

The present invention relates to a slurry for coating a laminated model and a three-dimensional object.

Conventionally, powder materials are bonded with a binder to form a powder solidified layer having a predetermined cross-sectional shape, and the powder solidified layers are sequentially laminated to form a shaped object having a desired three-dimensional shape. Additive manufacturing (also called three-dimensional modeling) is known. In this additional modeling, the modeling of resin products using a resin material is widely performed because of its ease of handling. However, in the additional molding of powder materials (powder laminated molding), powder materials made of ceramic materials, which are difficult to be precision processed after molding, are also widely used. Further, in order to increase the mechanical strength of the laminated model, it has been proposed to use the powder for laminated modeling containing ceramic powder to form the laminated model and then fire the laminated model. Patent Documents 1 to 3 are mentioned as technical documents relating to this kind of laminated molding. Patent Document 1 discloses a technique of applying a coating agent containing a resin adhesive material to the surface of a 3D modeled object in order to produce a modeled object having good appearance while having strength in a short time.

International Publication No. 2015/046217 JP-A-2015-226935 Japanese Unexamined Patent Publication No. 2017-52138

By the way, a laminated molded product using a powder material made of a ceramic material tends to have a large void between particles and a high porosity as compared with a ceramic molded product using a mold. Therefore, the texture when touched is poor, and the beautiful appearance tends to be impaired. There is a demand for a technique for obtaining a three-dimensional object having a beautiful appearance without impairing the original texture of ceramics. Further, in the case of firing a laminated modeled object, there is a demand for a three-dimensional shaped object having good dimensional accuracy after firing without heat shrinkage during firing.

The present invention has been made in view of this point, and a main object thereof is to provide a slurry for coating a laminated model, which can realize a three-dimensional shape having a good texture and dimensional accuracy after firing. To provide. Another related object is to provide a three-dimensional object constructed using such a laminated model coating slurry.

In order to realize the above object, according to the present invention, a paste or slurry-like composition for forming a porous coating layer on a laminated model (hereinafter, may be abbreviated as "slurry for coating a laminated model"). Provided. This slurry for coating a laminated model contains a powder material made of ceramics and a solvent. The powder material includes a first ceramic powder having an average particle size D1 and a second ceramic powder having an average particle size D2 smaller than the first ceramic powder. The average particle size D1 of the first ceramic powder is 3 μm or more and 30 μm or less. Here, the slurry has a viscosity η _{1 at} a rotation speed of 1 rpm of 1 mPa · s or more, a viscosity η _{10 at} a rotation speed of 10 rpm of 100 mPa · s or less, and the viscosity η ₁ and the viscosity. Viscosity ratio with η _{10 : η 1} / η ₁₀ is 0.8 or more and 1.5 or less. Here, the viscosities η ₁ and η ₁₀ are viscosities that can be measured by a commercially available viscometer. For example, by using a standard rheometer in the field, the viscosity can be easily measured under the above-mentioned rotation speed conditions. According to such a coating slurry, it is possible to realize a three-dimensional shape having a good texture and good dimensional accuracy after firing.

In a preferred embodiment of the coating slurry disclosed herein, the ratio of the contents of the powder material and the solvent (powder material: solvent) is in the range of 1: 1 to 1: 1 on a mass basis. Within such a content ratio, the above-mentioned effects can be realized at a higher level.

In a preferred embodiment of the coating slurry disclosed herein, the average particle size D2 of the second ceramic powder is 0.1 μm or more and less than 3 μm. When the particle size is within the range of the average particle size of the second ceramic powder, the above-mentioned effect can be more exerted.

In a preferred embodiment of the coating slurry disclosed herein, the ratio of the contents of the first ceramic powder and the second ceramic powder (first ceramic powder: second ceramic powder) is 5 on a mass basis. : 1 to 1: 5. When the content ratio of the first ceramic powder and the second ceramic powder is within the range, the performance improving effect by using the first ceramic powder and the second ceramic powder in combination is more preferably exhibited. Can be done.

In a preferred embodiment of the coating slurry disclosed herein, the first ceramic powder contains silica particles, and the second ceramic powder contains zircon particles. The first ceramic powder and the second ceramic powder containing such particles can effectively contribute to the improvement of the texture of the three-dimensional shaped object and the dimensional accuracy after firing.

Further, according to the present invention, there is provided a three-dimensional object having a porous coating layer on the surface of the laminated model. The coating layer is a slurry for coating a laminated model including a first ceramic powder having an average particle size D1 and a second ceramic powder having an average particle size D2 smaller than the first ceramic powder, and a solvent. It consists of a fired body of. The average pore diameter of the laminated model is 5 μm or more and 40 μm or less. The porosity of the laminated model is 30% or more and 70% or less. The arithmetic average surface roughness Ra of the coating layer is 50 μm or less. Such a three-dimensional object may be excellent in texture and dimensional accuracy.

Hereinafter, preferred embodiments of the present invention will be described. Matters other than those specifically mentioned in the present specification and necessary for carrying out the present invention can be grasped as design matters of those skilled in the art based on the prior art in the art. The present invention can be carried out based on the contents disclosed in the present specification and the common general technical knowledge in the art. In addition, in this specification, "ceramics" means an inorganic substance.

The slurry for coating a laminated model disclosed herein is used to form a porous coating layer on the laminated model. Typically, a technique for forming a three-dimensional object having a porous coating layer on the surface of the laminated model by applying the slurry to the surface of the laminated model and then firing the slurry together with the laminated model. Can be applied to. As the laminated model to be coated to which the slurry is applied, a desired three-dimensional object obtained by combining powders to form a powder solidified layer having a predetermined cross-sectional shape and sequentially laminating the powder solidified layers. The shape is not particularly limited as long as it is a laminated model. For example, a laminated model formed by a method such as a material injection inkjet lamination modeling method, a binder injection inkjet lamination method, a powder fixing type lamination method, a powder bed laser melting method, a powder bed thermal head melting method, or an electron beam melting method is preferable. Can be coated. The laminated model to be coated to which the slurry is applied may be a fired product fired after molding. The coating slurry disclosed herein is also suitable as a slurry used for coating a laminated molded product thus fired after molding.

<Slurry for coating laminated objects>
The slurry for coating a laminated model disclosed herein includes a powder material made of ceramics and a solvent. The viscosity at a rotation speed of 1 rpm (hereinafter, _{may be simply referred to as "η 1} ") is 1 mPa · s or more, and the viscosity at a rotation speed of 10 rpm (hereinafter, simply "η ₁₀ "). ) Is 100 mPa · s or less, and the viscosity ratio between the viscosity _{η 1} and the viscosity η _{10 : η 1} / η ₁₀ is 0.9 or more and 1.5 or less. Hereinafter, the viscosity of the slurry, the powder material, and the solvent will be described in this order.

<Slurry viscosity>
The slurry for coating a laminated model disclosed here has a viscosity η _{1 at} a rotation speed of 1 rpm of 1 mPa · s or more and a viscosity η _{10 at} a rotation speed of 10 rpm of 100 mPa · s or less. .. Typically, the viscosities η ₁ and η ₁₀ are viscosities measured by a commercially available rheometer at a liquid temperature of 25 ° C. at any of the above rotation speeds. The slurry for coating a laminated model disclosed here _{has a viscosity such that 1} mPa · s ≤ η 1 and η ₁₀ ≤ 100 mPa · s, so that when the slurry is applied to the surface of the laminated model, it is applied. The slurry does not easily soak into the inside of the laminated model, and the surface of the laminated model is uniformly coated.

_{That is, in the slurry for coating a laminated model in which the viscosity η 10} at a rotation speed of 10 rpm is η ₁₀ ≤ 100 mPa · s, the shear rate is increased as in the case where the slurry is applied to the surface of the laminated model. It has high fluidity in the above and easily wets and spreads on the surface of the laminated model. Therefore, when the slurry is applied to the surface of the laminated model, the amount of the slurry adhering to the laminated model becomes non-uniform depending on the location (for example, the slurry tends to accumulate on the unevenness of the laminated model). hard. From the viewpoint of making the amount of slurry adhering to the laminated model uniform, the viscosity η ₁₀ is preferably approximately η ₁₀ ≤ 100 _{mPa · s, more preferably η 10} ≤ 80 mPa · s, and η ₁₀ ≤. 50 mPa · s is more preferable, and η ₁₀ ≦ 30 mPa · s is particularly preferable. The viscosity η ₁₀ may be, for example, 20 mPa · s or less, and typically 15 mPa · s or less. The lower limit of the viscosity η ₁₀ is not particularly limited, but is, for example, 0.5 mPa · s or more. Viscosity eta _10, preferably 0.8mPa · s ≦ η _10, more preferably 1mPa · s ≦ η _10, more preferably 3mPa · s ≦ η _10, particularly preferably 5mPa · s ≦ η _10. The technique disclosed herein has an embodiment in which the viscosity η _{10 of the} slurry for coating a laminated model is 0.5 mPa · s ≤ η ₁₀ ≤ 100 mPa · s (preferably 5 mPa · s ≤ η ₁₀ ≤ 15 mPa · s). It can be preferably carried out.

_{Further, the slurry for coating a laminated model in which the viscosity η 1} at a rotation speed of 1 rpm is 1 mPa · s ≦ η ₁ is stable over time when it is allowed to stand (when it is allowed to stand at room temperature without performing operations such as stirring). Therefore, after the slurry is applied to the surface of the laminated model, the slurry does not easily permeate into the laminated model. Therefore, it is possible to suppress various defects that may occur when the slurry soaks into the inside of the laminated model. For example, the slurry soaked into the interior promotes densification (increased density) of the laminated model, and the laminated model is thermally shrunk during firing (the dimensional accuracy of the three-dimensional model obtained after firing is reduced). It is possible to suppress such problems. Therefore, it is possible to stably produce a higher quality three-dimensional model. From the standpoint of a suppressing penetration of slurry, the viscosity eta ₁ is preferably to 1mPa · s ≦ η _1, more preferably 1.5mPa · s ≦ η _1, more preferably 2mPa · s ≦ η ₁ , 2.5 mPa · s ≦ η ₁ is particularly preferable. The viscosity η ₁ may be, for example, 3 mPa · s or more, and typically 5 mPa · s or more. The upper limit of the viscosity η ₁ is not particularly limited, but is, for example, 50 mPa · s or less. Viscosity eta ₁ is preferably η ₁ ≦ 40mPa · s, more preferably η ₁ ≦ 30mPa · s, more preferably η ₁ ≦ 25mPa · s, particularly preferably η ₁ ≦ 20mPa · s. The technique disclosed herein is preferably carried out in an embodiment in which _{the viscosity η 1 of the} slurry for coating a laminated model is ₁ mPa · s ≦ η 1 ≦ 50 mPa · s (preferably 5 mPa · s ≦ η _{1 ≦ 18 mPa · s).} Can be done.

From the viewpoint of better exerting the effect of using the slurry having the above-mentioned viscosity characteristics, the viscosity ratio of _{viscosity η 1} to viscosity η _{10 : η 1} / η ₁₀ should be 0.8 or more and 1.5 or less. preferable. By preparing the slurry so as to have the above-mentioned specific viscosity ratio, both static stability and fluidity can be realized at a higher level. That is, when the slurry is applied to the surface of the laminated model, the slurry tends to spread uniformly on the surface of the laminated model, and once wet and spread, it does not easily flow (penetrates into the laminated model). It can be a slurry (difficult). In the technique disclosed herein, _{the relationship between η 1} and η ₁₀ is, for example, 0.82 ≦ (η ₁ / η ₁₀ ) ≦ 1.48, preferably 0.85 ≦ (η ₁ / η ₁₀ ) ≦ 1. It can be preferably carried out in an embodiment of .45, more preferably 0.88 ≦ (η ₁ / η ₁₀ ) ≦ 1.42, and even more preferably 0.9 ≦ (η ₁ / η _{10) ≦ 1.4.}

For example, η ₁₀ is preferably 0.3 mPa · s or more larger than _{η 1 and more preferably 0.5 mPa · s or more.} The value obtained by subtracting η _{1 from η 10} (that is, η _{10 − η 1} ) is preferably 15 mPa · s or less, more preferably 10 mPa · s or less, and further preferably 5 mPa · s or less. .. For example, η _{10 − η 1} may be 4 mPa · s or less (for example, 3 mPa · s or less).

<Powder material>
The slurry for coating a laminated model disclosed herein contains a powder material made of ceramics. The powder material includes a first ceramic powder having an average particle size D1 and a second ceramic powder having an average particle size D2 smaller than the first ceramic powder.

The shape (outer shape) of the first ceramic powder constituting the powder material is not particularly limited. It may be spherical or non-spherical. From the viewpoint of mechanical strength, ease of manufacture, and the like, a substantially spherical first ceramic powder can be preferably used. The average particle size D1 of the first ceramic powder is larger than the average particle size D2 of the second ceramic powder, and is 3 μm or more. According to the first ceramic powder having the average particle size D1, it is possible to obtain an appropriately porous coating layer when the slurry is applied to the surface of the laminated model and fired. The average particle size D1 of the first ceramic powder is preferably 5 μm or more, more preferably 6 μm or more, and particularly preferably 8 μm or more. The upper limit of the average particle size D1 of the first ceramic powder is not particularly limited, but it is appropriate to set it to about 30 μm or less. From the viewpoint of obtaining the surface of a laminated model having a good texture, the D1 is preferably 25 μm or less, more preferably 20 μm or less, still more preferably 18 μm or less, and particularly preferably 15 μm or less. The technique disclosed herein can be preferably carried out in an embodiment in which the average particle size D1 of the first ceramic powder is 3 μm or more and 20 μm or less (further, 5 μm or more and 15 μm or less, particularly 8 μm or more and 12 μm or less).

Unless otherwise specified, the term "average particle size" as used herein means the particle size at an integrated value of 50% in the particle size distribution measured based on the particle size distribution measuring device based on the laser scattering / diffraction method, that is, 50%. It shall mean the volume average particle size (D50 diameter). More specifically, the particle size is 50% volume average particle size measured by a wet method using a laser diffraction / scattering type particle size distribution measuring device without dispersing the particles by compressed air.

The slurry for coating a laminated model disclosed herein contains, in addition to the first ceramic powder, a second ceramic powder having an average particle size D2 smaller than that of the first ceramic powder. By using a combination of ceramic powder materials having different average particle sizes as described above, a slurry for coating a laminated model having the above-mentioned viscosity characteristics can be suitably realized. Further, when the slurry is applied to the surface of the laminated model and then fired, the particles of the second ceramic powder are arranged around the particles of the first ceramic powder, and the first ceramic powder is sintered with each other. Is better suppressed. As a result, the porous state of the coating layer obtained after firing can be suitably maintained.

The shape (outer shape) of the second ceramic powder constituting the powder material is not particularly limited. It may be spherical or non-spherical. From the viewpoint of mechanical strength, ease of manufacture, and the like, a substantially spherical first ceramic powder can be preferably used. The average particle size D2 of the second ceramic powder may be smaller than that of the first ceramic powder (that is, D2 <D1), and the slurry satisfies the relationship between the _{viscosities η 1} , η _{10 and the viscosity ratio.} The limit is not particularly limited. It is appropriate that D2 is, for example, less than 3 μm, usually 2 μm or less, typically 1 μm or less, preferably 0.8 μm or less. The lower limit of D2 is not particularly limited, but is preferably 0.05 μm or more, more preferably 0.1 μm or more, still more preferably 0.3 μm or more. For example, a second ceramic powder having a D2 of 0.05 μm or more and less than 3 μm is preferable, a powder having a D2 of 0.1 μm or more and 1 μm or less is more preferable, and a powder having a D2 of 0.5 μm or more and 0.8 μm or less is particularly preferable. The average particle size D2 is also suitable from the viewpoint of obtaining the surface of a three-dimensional object having a good texture.

The ratio of the contents of the first ceramic powder and the second ceramic powder is not particularly limited. From the viewpoint of better exerting the effect of using the first ceramic powder and the second ceramic powder in combination, the mass ratio of the first ceramic powder and the second ceramic powder (first ceramic powder: second). The ceramic powder) is preferably 10: 1 to 1:10, preferably 5: 1 to 1: 5, and more preferably 2: 1 to 1: 2. The technique disclosed herein can be preferably carried out, for example, in an embodiment in which the mass ratio of the first ceramic powder to the second ceramic powder is 3: 2 to 2: 3.

The materials and properties of the first ceramic powder and the second ceramic powder are not particularly limited. For example, each of the first ceramic powder and the second ceramic powder can be either an inorganic particle or an organic-inorganic composite particle. As the ceramic particles constituting the first ceramic powder and the second ceramic powder, inorganic particles are preferable, and particles made of a metal or semi-metal compound are particularly preferable. For example, in addition to oxide-based ceramics composed of oxides of any of the elements belonging to Group 1 to Group 14 (for example, Group 4 to Group 14) of the periodic table, nitrides and carbides of various metal elements, Non-oxide ceramics made of boride, carbide, phosphoric acid compound and the like, and ceramic particles mainly composed of composite ceramics thereof can be preferably used. Among them, Si, B, Al, Ba, Ca, Mg, Li, Na, K, Zn, Sr, Sn, Sb, Bi, Te, Pb, W, Ti, Y, Zr, Ni, Fe and Ag. Ceramic particles mainly composed of oxides, nitrides, and carbides containing any metal element or metalloid element are preferable. Alternatively, ceramic particles composed mainly of a metal containing any element belonging to Group 1 to Group 13 (for example, Group 4 to Group 13) of the periodic table or an alloy thereof may be adopted.

Examples of oxide-based ceramics include alumina (Al ₂ O ₃ ), zirconia (ZrO ₂ ), ittria (Y ₂ O ₃ ), talc (Mg ₂ Si ₄ O ₁₀ ), hematite (Fe ₂ O ₃ ), and chromia. (Cr ₂ O ₃ ), Titania (Ti ₂ O), Magnesia (MgO), Silica (SiO ₂ ), Calcia (CaO), Celia (CeO ₂ ), Tin Oxide (TO; SnO ₂ ), Steatite (MgO. SiO _2), cordierite _{(2MgO · 2Al 2 O 3 ·} 5SiO 2), mullite _{(3Al 2 O 3 · 2SiO 2} ), ferrite (MnFe ₂ O _4), spinel (MgAl ₂ O _4), zircon (ZrSiO ₄ ), barium titanate (BaTiO _3), lead titanate (PbTiO _3), Fuorusu Te write _(Mg 2 _SiO 4), phosphorus-doped tin oxide (PTO), antimony doped tin oxide (ATO), indium tin oxide (ITO) or the like Can be mentioned. Of these, zircon, alumina, silica, mullite and zirconia are preferable, and zircon, mullite and silica are more preferable.

As the non-oxide ceramics, for example, boron nitride (BN), titanium nitride (TiN), silicon nitride _{(Si 3 N} 4), gallium nitride (GaN), aluminum nitride (AlN), carbon nitride (CN _x ), _{Nitride ceramics such as Sialon (Si 3} N _4- AlN-Al ₂ O ₃ solid solution; Sialon), tungsten carbide (WC), chromium carbide (CrC), vanadium carbide (VC), niobide (NbC), carbide. molybdenum (MoC), tantalum carbide (TaC), titanium carbide (TiC), zirconium carbide (ZrC), hafnium carbide (HfC), silicon carbide (SiC), boron carbide _(B 4 C) carbide ceramics such as boride, Porrolithometer ceramics such as molybdenum (MoB), chromium boride (CrB ₂ ), hafnium borate (HfB ₂ ), zirconium borate (ZrB ₂ ), tantalum borate (TaB ₂ ), titanium borate (TiB ₂₎ , Zirconium oxide silicate, Hafnium oxide silicate, Titanium oxide silicate, Lantern oxide silicate, Ittrium oxide silicate, Titanium oxide silicate, Tantal silicate, Tantal oxynitride, etc. Can be mentioned. In a preferred embodiment, the first ceramic powder and the second ceramic powder can be selected so that the melting point of the second ceramic powder is higher than the melting point of the first ceramic powder.

Specific examples of the particles that can be preferably used as the first ceramic powder include silica particles, alumina particles, zirconia particles, titania particles, zinc oxide particles and the like. These particles are preferable in that they can form a fired body having a good texture. One of these particles may be used alone, or two or more of these particles may be used in combination. Of these, silica particles, alumina particles, and zirconia particles are preferable. Specific examples of the particles that can be preferably used as the second ceramic powder include zircon particles, alumina particles, mullite particles, calcia particles, magnesia particles, and the like. One of these particles may be used alone, or two or more of these particles may be used in combination. Of these, zircon particles are preferable.

Here, when firing the laminated model after applying the slurry for coating the laminated model, it is necessary to fire the laminated model in a high temperature range of 1000 ° C. or higher (preferably 1200 ° C. or higher). Therefore, as the firing jig (for example, sand) used when firing the laminated model, it is desirable to use a jig made of a highly heat-resistant metal compound such as alumina, mullite, cordeurite, and silicon carbide. .. However, these metal compound firing jigs may react with the ceramic powder contained in the coating slurry in the firing temperature range of 1000 ° C. or higher. When the ceramic powder and the firing jig react with each other, the ceramic powder and the firing jig may adhere to each other, and when the fired body is taken out from the firing jig, a three-dimensional shape having a good texture may not be obtained. .. Therefore, it is desirable to appropriately suppress the reaction between the ceramic powder contained in the coating slurry and the firing jig in the firing step.

In a preferred embodiment, the first ceramic powder and the second ceramic powder have a lower reactivity with the firing jig (for example, sand) in the second ceramic powder than in the first ceramic powder. Select to. By doing so, the second ceramic powder particles having low reactivity with the firing jig are arranged around the first ceramic powder particles, and the first ceramic powder having high reactivity with the firing jig is fired. Direct contact with the jig is hindered. As a result, the reaction between the ceramic powder and the firing jig during firing is effectively suppressed, and a fired product (three-dimensional shape) having a good texture can be obtained. For example, when silica particles are used as the first ceramic powder, zircon particles can be preferably used as the second ceramic powder.

<Solvent>
The solvent used for the slurry for coating a laminated model is not particularly limited as long as it can disperse the above-mentioned powder material. For example, an aqueous solvent can be used. As the water-based solvent, water or a mixed solvent mainly composed of water is preferably used. As the solvent component other than water constituting the mixed solvent, one or more organic solvents (lower alcohols, lower ketones, etc.) that can be uniformly mixed with water can be appropriately selected and used. For example, it is preferable to use an aqueous solvent in which 80% by mass or more (more preferably 90% by mass or more, still more preferably 95% by mass or more) of the aqueous solvent is water. A particularly preferable example is an aqueous solvent which is substantially composed of water. The solvent used for the slurry for coating a laminated model is not limited to an aqueous solvent, and may be a non-aqueous solvent (organic solvent). As the non-aqueous solvent, for example, alcohols such as ethyl alcohol and isopropyl alcohol; and the like can be used.

The ratio of the contents of the powder material and the solvent in the slurry for coating a laminated model (powder material: solvent) is _{particularly limited as long as the viscosities η 1} and η ₁₀ of the above-mentioned slurry satisfy the above range and the above-mentioned viscosity ratio. There is no, but it is in the range of 1: 5 to 5: 1 on a mass basis. The content ratio is preferably 1: 4 to 4: 1, more preferably 1: 3 to 3: 1. The ratio of the contents of the powder material and the solvent may be, for example, 1: 1-3: 1 or 1: 1 to 5: 2. When it is within the range of the content ratio of the powder material and the solvent, the above-mentioned performance improving effect can be better exhibited.

<Dispersant>
The slurry for coating a laminated model disclosed herein may contain a dispersant. The dispersant is a component added for the purpose of stably dispersing the powder material in the slurry, and a surfactant is typically used. Examples of the dispersant include high molecular weight polycarboxylic acids and the like. The content of the dispersant in the slurry for coating a laminated model is not particularly limited, but it is usually appropriate to be 0.1% by mass to 3% by mass.

<Other ingredients>
The slurry for coating a laminated model disclosed herein includes, if necessary, a known additive such as a thickener, a rust preventive, an antiseptic, and an antifungal agent, as long as the effect of this composition is not impaired. It may be contained. The content of the additive may be appropriately set according to the purpose of the addition and does not characterize the present invention, and therefore detailed description thereof will be omitted.

<Preparation of slurry for coating laminated model>
The method for preparing the slurry for coating the laminated model is not particularly limited. For example, it is preferable to mix each component contained in the slurry for coating a laminated model by using a well-known mixing method. The mode in which these components are mixed is not particularly limited, and for example, all the components may be mixed at once, or may be mixed in an appropriately set order.

Since the slurry for coating a laminated model disclosed herein can coat the surface of the laminated model to highly reduce the surface roughness of the laminated model, a surface with a good texture is required for the laminated model. It can be preferably applied as a coating agent for an object. Therefore, according to this specification, a method for manufacturing a three-dimensional object (a three-dimensional object having a porous coating layer on the surface of a laminated model) including a coating step using the slurry, and a three-dimensional shape produced by the method. Things are provided. The laminated modeled product coated with the slurry for coating the laminated modeled product may be a laminated model product obtained through steps such as modeling and firing.

The slurry for coating a laminated model disclosed herein can be suitably used for a method for producing a three-dimensional object, for example, in an embodiment including the following operations. Hereinafter, a preferred embodiment of a method for producing a three-dimensional shape using the slurry for coating a laminated model disclosed herein will be described. The method for manufacturing a three-dimensional shaped object according to a preferred embodiment includes a step of preparing a laminated model (a step of preparing a laminated model) and a step of applying a slurry for coating the laminated model to the surface of the laminated model (coating step). , A step (baking step) of firing the laminated model to which the slurry is applied is included.

<Laminated model preparation process>
In the step of preparing the laminated model, the laminated model is prepared. Preparing the above-mentioned laminated model may include modeling the laminated model. For example, it is advisable to prepare a laminated modeling powder containing ceramic particles for laminated modeling, and to use the powder for laminated modeling to form a laminated model by a conventionally known method. As the ceramic particles for laminated molding, one of the above-mentioned materials exemplified as the first ceramic powder and the material of the first ceramic powder can be used alone or in combination of two or more. For example, alumina particles, zirconia particles, zircone particles, titania particles, silica particles, zinc oxide particles, barium titanate particles, aluminum particles, nickel particles, iron particles and the like can be used. The average particle size of the ceramic particles for laminated molding is not particularly limited, but may be, for example, 5 μm to 100 μm, typically 10 μm to 80 μm, for example, 15 μm to 70 μm. The average particle size of the ceramic particles for laminated molding may be 20 μm to 50 μm. The laminated molding powder may contain components other than the laminated molding ceramic particles, if necessary. Examples of such a component include a binder, a surfactant and the like. Examples of the binder include thermoplastic resins such as isobutylene resin, polyamide resin, polyester resin, polyether resin, polyvinyl alcohol resin, polyethylene glycol resin, thermosetting resin such as melamine resin, and cellulose derivative. Such as polysaccharides are exemplified.

Further, preparing the laminated model may include firing the laminated model. For example, the above-mentioned laminated model may be fired at a predetermined firing temperature (for example, 1300 ° C to 1600 ° C). Since the above-mentioned modeling method and the above-mentioned firing method do not characterize the present invention, detailed description thereof will be omitted.

In a preferred embodiment, the average pore diameter of the laminated model to which the slurry is applied is approximately 5 μm or more and 40 μm or less. The average pore diameter of the laminated model may be, for example, 15 μm or more, and typically 25 μm or more (for example, 35 μm or more). The porosity of the laminated model is approximately 30% or more and 70% or less. The porosity of the laminated model may be, for example, 50% or more, and typically 60% or more (for example, 65% or more). Further, the arithmetic average surface roughness Ra of the laminated model may satisfy 15 μm or more (for example, 20 μm or more, typically 40 μm or more). Laminated objects having such a large average pore diameter, porosity and surface roughness tend to have a poor texture when touched and a beautiful appearance is apt to be impaired. Therefore, the effect of applying the slurry having this configuration (for example, the effect of improving the texture) can be more preferably exhibited. In addition, in this specification, "average pore diameter" and "porosity" are measured by using a mercury intrusion method, and a multi-value is adopted unless otherwise specified.

<Coating process>
In the coating step, after the above-mentioned laminated model is prepared, a slurry for coating the laminated model is applied (typically applied) to the surface of the laminated model. The coating method is not particularly limited as long as the slurry can be uniformly coated on the surface of the laminated model. For example, a method of immersing the laminated model in the slurry (for example, a dip coating method), a method of spraying the slurry on the laminated model, or the like can be adopted. When the laminated model is immersed in the slurry, the immersion time may be such that the slurry is sufficiently wet and spread on the surface of the laminated model, and is usually 10 seconds to 120 seconds. After removing the laminated model from the slurry, it may be naturally dried before firing. The drying time is not particularly limited, but is approximately 0.5 to 2 hours.

<Baking process>
In the firing step, after the coating step, the laminated model is fired to obtain a three-dimensional shaped object. Preferably, in an oxygen atmosphere, the maximum firing temperature is determined within the range of 1000 ° C. or higher and lower than 1300 ° C. As a result, the solvent in the slurry for coating the laminated model, which is applied to the surface of the laminated model, is removed, and the first ceramic powder and the second ceramic powder are sintered. This makes it possible to manufacture a three-dimensional model in which a porous coating layer is formed on the surface of the laminated model. The firing step is preferably performed so that the maximum firing temperature is 1100 ° C. or higher (preferably 1100 ° C. to 1250 ° C., for example, 1150 ° C. to 1250 ° C.). The firing time (baking time at the maximum firing temperature) is preferably about 1 hour to 5 hours. In this way, the production of the three-dimensional shaped object according to the present embodiment is completed.

<Three-dimensional shape>
The three-dimensional shape disclosed here is a laminate containing a first ceramic powder having an average particle size D1, a second ceramic powder having an average particle size D2 smaller than the first ceramic powder, and a solvent. It is manufactured by applying a slurry for coating a modeled object to the surface of a laminated modeled object and then firing it. Therefore, the obtained three-dimensional object can have a porous coating layer having a smaller surface roughness than the conventional one. Typically, the arithmetic average surface roughness Ra of the coating layer can be 50 μm or less, for example 45 μm or less (for example, 0.5 μm to 45 μm), preferably 38 μm or less, and more preferably 30 μm or less. A three-dimensional object provided with such a coating layer may have a good texture when touched and an excellent appearance.

Hereinafter, some examples of the present invention will be described, but the present invention is not intended to be limited to those shown in the examples. In the following description, "%" is a mass standard (mass%) unless otherwise specified.

<Laminated model>
Laminated modeling powder containing ceramic particles (material alumina, average particle size 20 μm was used) was put into a 3D modeling machine, and five layers of length 4 mm × width 40 mm × thickness 0.1 mm were stacked. Three types of laminated shaped objects A to C were modeled. Then, each of the laminated shaped objects A to C was fired in alumina sand at 1400 ° C. to obtain a fired body of the laminated shaped objects A to C. Table 1 summarizes the average pore diameter, porosity, and surface roughness Ra of the obtained laminated model (fired body) A to C.

The average pore diameter and porosity of the laminated shaped objects A to C are volume-based median diameters measured by the above method using the pore distribution measuring device "AutoPore IV9500" manufactured by Micromeritics Instrument Corporation. The surface roughness Ra is the value of the arithmetic mean roughness Ra on the laminated surfaces (5 sheets) of the laminated shaped objects A to C measured by the shape measuring microscope "VK-9700" manufactured by KEYENCE CORPORATION.

<Slurry for coating laminated objects>
Examples 1 to 9 and Examples 1 to 9 and 9 were mixed with silica particles as the first ceramic powder, zircon particles as the second ceramic powder, a high molecular weight polycarboxylic acid as a dispersant, and ethyl alcohol as a solvent. The slurry for coating the laminated model of Comparative Examples 1 to 3 was prepared. The mass ratio of the first ceramic powder and the second ceramic powder was 1: 1. The amounts of the solvent used with respect to the total mass of 200 g of the first ceramic powder and the second ceramic powder were Examples 1 to 3: 200 g, Examples 4 to 6: 100 g, Examples 7 to 9: 80 g, and Comparative Examples. It was 1 to 3: 60 g. Viscosity η _{1 at rotation speed: 1 rpm, viscosity η 10 at} rotation speed: 10 rpm, viscosity ratio (η ₁ / η ₁₀ ), first ceramic powder used The average particle size D1 of the above and the average particle size D2 of the second ceramic powder are summarized in Table 2.

The viscosity of the slurry of each example was measured by the above method using a programmable rheometer "DV-III Ultra" manufactured by Brookfield. The average particle sizes D1 and D2 were measured by the above method using "Master Sizar 3000" of Malvern Instruments Ltd.

<Three-dimensional shape>
The slurry of each example is applied and coated on the surfaces of the laminated shaped objects (baked bodies) A to C by the dip coating method (coating step), and then fired in alumina grain sand at 1200 ° C. ( (Baking step), three-dimensional shaped objects A to C having a porous coating layer on the surface of the laminated model were obtained. Then, in the coating step, it was visually confirmed whether or not the slurry was uniformly adhered to the surface of the laminated model. Here, the one in which the slurry adhered uniformly to the laminated model was evaluated as “◯”, and the one in which the slurry adhered unevenly as the dimensional ratio of the laminated model changed was evaluated as “x”. In addition, the value of the surface roughness Ra of the coating layer of the three-dimensional shaped object of Examples 1 to 9 after firing was measured. The surface roughness Ra is a value of the arithmetic average roughness Ra on the laminated surface (five sheets) of the three-dimensional shaped object measured by the shape measuring microscope "VK-9700" manufactured by KEYENCE CORPORATION. The results are shown in the columns of "Applicability" and "Surface roughness Ra after coating" in Table 2, respectively.

As shown in Tables 1 and 2, the slurries according to Comparative Examples 1 to 3 had too high a viscosity and non-uniformly adhered to the laminated model, resulting in poor coatability. On the other hand, the slurries of Examples 1 to 9 were uniformly adhered to the surface of the laminated model, and the coatability was good. In addition, the penetration of the slurry into the laminated model after the coating step was suppressed, and the dimensional accuracy after firing was good. Further, the surface roughness Ra after coating was also generally reduced, and the texture was improved as compared with that before coating.

Although specific examples of the present invention have been described in detail above, these are merely examples and do not limit the scope of claims. The techniques described in the claims include various modifications and modifications of the specific examples exemplified above.

Claims (6)

A slurry for forming a porous coating layer on a laminated model.
Contains a powder material made of ceramics and a solvent,
The powder material contains a first ceramic powder having an average particle size D1 and a second ceramic powder having an average particle size D2 smaller than the first ceramic powder.
The average particle size D1 of the first ceramic powder is 3 μm or more and 30 μm or less.
Here, the slurry is
_{The viscosity η 1 at} the rotation speed: 1 rpm is 1 mPa · s or more, and
Rotation speed: Viscosity η _{10 at} 10 rpm is 100 mPa · s or less,
Viscosity ratio of the viscosity η ₁ to the viscosity η _{10 : η 1} / η ₁₀ is 0.8 or more and 1.5 or less.
Slurry for coating laminated objects. The slurry for coating a laminated model according to claim 1, wherein the ratio of the contents of the powder material and the solvent (powder material: solvent) is in the range of 1: 1 to 1: 1 on a mass basis. The slurry for coating a laminated model according to claim 1 or 2 , wherein the average particle size D2 of the second ceramic powder is 0.1 μm or more and less than 3 μm. Claim 1 in which the ratio of the contents of the first ceramic powder and the second ceramic powder (first ceramic powder: second ceramic powder) is in the range of 5: 1 to 1: 5 on a mass basis. The slurry for coating a laminated model according to any one of 3 to 3. The first ceramic powder contains silica particles and contains
The slurry for coating a laminated model according to any one of claims 1 to 4 , which contains zircon particles as the second ceramic powder. It is a three-dimensional object with a porous coating layer on the surface of the laminated model.
The coating layer is a slurry for coating a laminated model including a first ceramic powder having an average particle size D1 and a second ceramic powder having an average particle size D2 smaller than the first ceramic powder, and a solvent. Consists of a fired body of
The average pore diameter of the laminated model is 5 μm or more and 40 μm or less.
The porosity of the laminated model is 30% or more and 70% or less.
A three-dimensional object having an arithmetic average surface roughness Ra of the coating layer of 50 μm or less.