Methods for manufacturing styling liquid, styling kits and styling objects

Abstract

This invention relates to a molding liquid, molding kits, and a method for manufacturing molded objects. The objective of this invention is to provide a molding liquid that can produce molded objects with excellent dimensional accuracy. The molding liquid of this invention is a molding liquid added to a powder layer containing inorganic particles, wherein the contact angle θ between the molding liquid and the inorganic particles is 50° or more, and satisfies the following formula: γcosθ / η≤1.5 (m / s). In the above formula, θ represents the contact angle (°) between the molding liquid and the inorganic particles, γ represents the surface tension (mN / m) of the molding liquid at 23°C, and η represents the viscosity (mPa·s) of the molding liquid at 25°C.

Description

Technical Field

[0001] This invention relates to a method for manufacturing styling liquid, styling kits, and styling objects. Background Technology

[0002] In recent years, there has been an increasing demand for the production of complex and intricately shaped objects made of metal. As a technology to meet this demand, especially from the point of view of high productivity, there is a method to densify sintering precursors shaped by binder spraying (hereinafter also known as the "BJ method") using powder metallurgy.

[0003] The BJ process typically uses water-based molding solutions, which are unsuitable for powders containing metal particles such as aluminum and magnesium that are unsuitable for contact with water. Therefore, research is underway on organic solvent-based molding solutions for metal particles that are unsuitable for water contact. However, organic solvent-based molding solutions generally have higher wettability on metal particle surfaces than water-based molding solutions, thus presenting a problem of not being able to obtain molded objects with the target dimensional accuracy.

[0004] To solve this problem, methods for controlling the wettability of organic solvent-based modeling liquids on the surface of metal particles include, for example, coating metal particles with resin (see Patent Document 1), and adding organic particles to the modeling liquid (see Patent Document 2).

[0005] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2016-107465

[0007] [Patent Document 2] Japanese Patent Application Publication No. 2018-154074 Summary of the Invention

[0008] The purpose of this invention is to provide a molding liquid that can produce molded objects with excellent dimensional accuracy.

[0009] As a method for solving the above-mentioned problems, the molding liquid of the present invention is a molding liquid added to a powder layer containing inorganic particles, wherein the contact angle θ between the powder and the inorganic particles is 50° or more, and satisfies the following formula: γcosθ / η≤1.5(m / s).

[0010] Here, θ represents the contact angle (°) between the molding liquid and the inorganic particles, γ represents the surface tension (mN / m) of the molding liquid at 23℃, and η represents the viscosity (mPa·s) of the molding liquid at 25℃.

[0011] According to the present invention, a molding liquid is provided that can produce molded objects with excellent dimensional accuracy. Attached Figure Description

[0012] Figure 1AThis is a schematic diagram illustrating an example of a shape achieving its target dimensions.

[0013] Figure 1B This is a schematic diagram illustrating an example of the state in which the molding liquid seeps from the target size into the non-molding area.

[0014] Figure 1C This is a schematic diagram illustrating an example of a state where localized seepage occurs from the target size.

[0015] Figure 2 This is a graph showing the relationship between the amount of molding liquid added and the bending strength of the molded object.

[0016] Figure 3A This is a schematic diagram illustrating an example of the operation of a manufacturing device for three-dimensional objects.

[0017] Figure 3B These are schematic diagrams illustrating other examples of the operation of a manufacturing apparatus for three-dimensional objects.

[0018] Figure 3C These are schematic diagrams illustrating other examples of the operation of a manufacturing apparatus for three-dimensional objects.

[0019] Figure 3D These are schematic diagrams illustrating other examples of the operation of a manufacturing apparatus for three-dimensional objects.

[0020] Figure 3E These are schematic diagrams illustrating other examples of the operation of a manufacturing apparatus for three-dimensional objects.

[0021] Figure 4 It is a front view (viewed from the side) of the device that shows the overall structure of the apparatus for manufacturing three-dimensional objects.

[0022] Figure 5 It is a diagram used to illustrate the conditions under which the ejected medium may adhere to the nozzle surface by ejecting droplets.

[0023] Figure 6 This is a diagram illustrating an example of an implementation where the nozzle surface is immersed in the cleaning fluid.

[0024] Figure 7 This is a diagram illustrating an example of an implementation of cleaning the nozzle surface via a cleaning fluid spraying mechanism.

[0025] Figure 8A This is a diagram representing a pattern state where the ejected lines are not blurred (a state without color mixing: ○).

[0026] Figure 8B It is a diagram representing the state of a blurred pattern (color mixing state: △) of the ejected lines.

[0027] Figure 8CThis is a diagram representing a pattern state where the ejected lines are quite blurry (mixed color state: ×).

[0028] Figure 9 This is a schematic diagram illustrating an example of the nozzle face cleaning fluid ejection mechanism used in the embodiment.

[0029] Figure 10A It is a photograph showing the state of the nozzle surface after cleaning.

[0030] Figure 10B It is a photograph showing the state of powder adhering to the nozzle surface.

[0031] Figure 10C This is a photograph showing the state of the nozzle surface after cleaning and maintenance at a moving speed of 10 m / s.

[0032] Figure 10D This is a photograph showing the state of the nozzle surface after cleaning and maintenance at a moving speed of 30 mm / s.

[0033] Figure 10E This is a photograph showing the state of the nozzle surface after cleaning and maintenance at a moving speed of 50 mm / s.

[0034] Specific Implementation Form

[0035] (Styling liquid)

[0036] The molding liquid of the present invention is a molding liquid added to a powder layer containing inorganic particles, wherein the powder contact angle θ with the inorganic particles is 50° or more, and satisfies the following formula: γcosθ / η≤1.5(m / s).

[0037] Here, θ is the powder contact angle (°) between the molding liquid and the inorganic particles, γ is the surface tension of the molding liquid at 23℃ (mN / m), and η is the viscosity of the molding liquid at 25℃ (mPa·s).

[0038] Here, when the type of inorganic particles used for determining the powder contact angle θ between the molding liquid and inorganic particles is known, these inorganic particles are used. On the other hand, when the type of inorganic particles used for molding is unknown, aluminum particles are used. Therefore, even if the type of inorganic particles used for molding is unknown (when the inorganic particles cannot be determined), as long as the molding liquid is known, aluminum particles can be used as the inorganic particles to determine the "powder contact angle θ" and "γcosθ / η≤1.5". For example, ALSI3-30B manufactured by Toyo Aluminum Co., Ltd. can be used as the aluminum particles.

[0039] In conventional methods of coating metal particles with resin and adding organic particles to the molding liquid, if an organic solvent-based molding liquid is used, the vapor of the organic solvent generated during the drying process of the molding liquid will not dissolve the coating resin and organic particles on the metal particles in the non-molding part of the molding liquid, resulting in a problem of deterioration in dimensional accuracy until the non-molding part is cured.

[0040] The molding liquid of this invention is an organic solvent-based molding liquid used in the BJ method. By controlling the "powder contact angle θ between the molding liquid and inorganic particles", "viscosity γ of the molding liquid at 25°C", "surface tension η of the molding liquid at 23°C" and "γcosθ / η" within a suitable range, the sprayability is good, the seepage of the molding liquid into non-molding parts is suppressed, and a molded object with target dimensional accuracy and high bending strength can be obtained.

[0041] <Viscosity η of the modeling liquid>

[0042] The viscosity η of the molding liquid at 25°C is preferably 6 mPa·s or more, more preferably 12 mPa·s or more, and even more preferably 15 mPa·s or more. Furthermore, it is preferably 50 mPa·s or less, more preferably 30 mPa·s or less, even more preferably 25 mPa·s or less, more preferably 21 mPa·s or less, particularly preferably 19 mPa·s or less, and even more particularly preferably 18.5 mPa·s or less.

[0043] When the viscosity η of the molding liquid is within the above range, the molding liquid imparting device, such as the nozzle, sprays out stably, and because the molding liquid is sprayed out correctly, the bending strength of the molded object before sintering, such as the cured material and the green blank derived from the cured material, is improved, and the dimensional accuracy of the molded object is improved.

[0044] The viscosity η of the molding liquid at 25°C can be measured at 25°C using, for example, a cone-plate viscometer VISCOMETER TV-25 manufactured by Toki Sangyo Co., Ltd.

[0045] <Surface tension γ of the modeling liquid>

[0046] The surface tension γ of the molding liquid at 23°C is preferably 20 mN / m or more, more preferably 22 mN / m or more, even more preferably 25 mN / m or more, and particularly preferably 27 mN / m or more. Furthermore, it is preferably 40 mN / m or less, more preferably 35 mN / m or less, even more preferably 31 mN / m or less, and particularly preferably 30 mN / m or less.

[0047] When the surface tension γ is within the above range, the spraying of the molding liquid from the nozzle and the like is stable. Because the correct molding liquid is sprayed out, the bending strength of the cured material and the green blank derived from the cured material before sintering is improved, and the dimensional accuracy of the molded material is improved.

[0048] The surface tension γ of the modeling fluid at 23°C can be measured, for example, using the Wilhelmy method (suspension plate method) with the automatic surface tension meter DY-300 manufactured by Kyowa Interface Science Co., Ltd.

[0049] <Contact angle θn of the modeling liquid (flat plate method)>

[0050] Generally speaking, organic solvent-based modeling liquids have higher wettability on inorganic particle surfaces than water-based modeling liquids, and the contact angle θn (plate method) of the modeling liquid is actually less than 15°.

[0051] The contact angle θn between the molding liquid and the metal plate can be measured, for example, using the contact angle meter DMs-301 manufactured by Kyowa Interface Science Co., Ltd., at 25°C via the droplet method.

[0052] As the metal plate, an aluminum-free plate A 6061 LNQ-25-10-5 manufactured by Misumi Corporation was used. The syringe was filled with molding fluid, and an approximately 2.0 microliter droplet was dropped onto the metal plate using the automatic droplet forming function. After 20 seconds, the contact angle θn (plate method) was calculated from the droplet shape using the value obtained by the θ / 2 method.

[0053] <Powder contact angle θ between molding fluid and inorganic particles>

[0054] The contact angle θ between the molding liquid and the inorganic particles is 50° or more, preferably 52° or more, more preferably 55° or more, further preferably 60° or more, and particularly preferably 65° or more. Furthermore, it is preferably 80° or less, more preferably 76° or less, further preferably 75° or less, particularly preferably 70° or less, especially preferably 69° or less, and even more preferably 68° or less. When the contact angle θ is 50° or more, it can prevent the molding liquid from seeping into non-molding areas, and can stably obtain molded objects with the target dimensional accuracy.

[0055] The contact angle θ between the molding liquid and the inorganic particles is a value calculated based on the penetration rate of the molding liquid into a column filled with powder containing inorganic particles. For example, it can be measured using an automatic surface tension meter DY-500 manufactured by Kyowa Interface Science Co., Ltd. as follows.

[0056] When the type of inorganic particles used in the molding process is known, these inorganic particles are used. On the other hand, when the type of inorganic particles used in the molding process is unknown, aluminum powder (ALSI3-30B manufactured by Toyo Aluminum Co., Ltd.) is used.

[0057] Fill the column with 5g of powder containing inorganic particles and use a powder compressor to adjust the porosity to 35.6% to 35.8%.

[0058] As a liquid with sufficiently high wettability to powders containing inorganic particles, acetone is used. Assuming the powder contact angle θ of acetone is 0 degrees, the capillary radius is calculated. The "capillary radius" refers to the radius of the gap between inorganic particles when the column is filled with metal particles, and it can be measured using an automatic surface tension meter DY-500 manufactured by Kyowa Interface Science Co., Ltd.

[0059] Next, using an automatic surface tension meter DY-500 manufactured by Kyowa Interface Science Co., Ltd., the penetration rate of the molding liquid into the powder containing inorganic particles was measured within a range of 150 to 180 seconds from the start of the measurement. The penetration rate of the molding liquid into the powder containing inorganic particles was expressed by the Lucas-Washburn formula of the following equation (1).

[0060]

[0061] Here, in equation (1), l(t) wetted denoted as t, where t is the measurement time, r is the average capillary radius, γ is the surface tension of the molding liquid at 23℃, θ is the contact angle between the molding liquid and the inorganic particles, and η is the viscosity of the molding liquid at 25℃.

[0062] Based on the obtained capillary radius, permeation velocity, viscosity γ of the molding liquid at 25°C, and surface tension n of the molding liquid at 23°C, the powder contact angle θ between the molding liquid and the inorganic particles is calculated according to the above formula (1). The molding liquid is used to measure 3 times, and the minimum value is taken as the powder contact angle θ.

[0063] <γcosθ / η>

[0064] The molding fluid of the present invention satisfies the following formula: γcosθ / η≤1.5 (m / s), preferably satisfies the following formula: γcosθ / η≤1 (m / s), more preferably satisfies: γcosθ / η≤0.8 (m / s). Furthermore, γcosθ / η is preferably 0.1 (m / s) or more, more preferably 0.3 (m / s) or more, even more preferably 0.4 (m / s) or more, even more preferably 0.5 (m / s) or more, and particularly preferably 0.6 (m / s) or more.

[0065] By ensuring that the molding fluid satisfies the following formula: γcosθ / η≤1.5(m / s), the leakage of the molding fluid into non-molding areas can be suppressed, and the target dimensional accuracy can be obtained stably.

[0066] As an indicator of the penetration rate of the molding liquid into inorganic particles, “γcosθ / η” is calculated.

[0067] Here, θ represents the contact angle (°) between the molding liquid and the inorganic particles, γ represents the surface tension (mN / m) of the molding liquid at 23℃, and n represents the viscosity (mPa·s) of the molding liquid at 25℃.

[0068] In one embodiment of the present invention, the amount of modeling liquid applied is preferably 0.033 μl / mm. 3 Above and 0.33 μl / mm 3 The following is more preferably 0.148 μl / mm 3 Above and 0.33 μl / mm 3 the following.

[0069] When the amount of modeling liquid applied is 0.033 μl / mm 3 Above and 0.33 μl / mm 3 The following measures can prevent localized seepage of the modeling liquid. When the amount of modeling liquid applied is 0.148 μl / mm... 3 Above and 0.33 μl / mm 3 The following can improve the bending strength of the object.

[0070] When the amount of modeling liquid applied is less than 0.033 μl / mm 3 The molded object may collapse if the amount of molding fluid applied exceeds 0.33 μl / mm. 3 At this time, the styling liquid may seep out locally.

[0071] The amount of styling liquid applied can be determined using, for example, the following steps: The required number of drops are applied from the nozzle onto a pre-weighed OHP sheet. The total weight of the applied styling liquid is calculated from the difference between the original weight and the weight before application. Then, the volume of each drop of styling liquid in each nozzle is calculated by dividing the total weight of the styling liquid by the number of nozzles used for application, the number of droplets, and the specific gravity of the styling liquid. The volume of each drop of styling liquid in each nozzle is multiplied by the number of droplets applied to one voxel to obtain the volume of styling liquid applied to one voxel. This volume is then converted to a per-mm² volume. 3 The amount of modeling fluid applied is determined by the volume of the modeling fluid. The size of a voxel can be calculated based on the resolution and stack thickness in the main and sub-scanning directions.

[0072] Here, in the molding liquid of the present invention, by controlling the "contact angle θ between the powder and the metal particles of the molding liquid", the "viscosity γ of the molding liquid at 25°C", the "surface tension η of the molding liquid at 23°C", and "γcosθ / η" within appropriate ranges, the following can be obtained: Figure 1A and Figure 1B The molded liquid is shown to prevent seepage from the target size 1 to the non-molded area 2, thus obtaining a molded object with the target size accuracy.

[0073] On the other hand, by setting the amount of modeling liquid applied to 0.033 μl / mm 3 Above and 0.33 μl / mm 3 Below, the styling liquid is unlikely to overflow, such as Figure 1C As shown, this can prevent localized seepage 3 from the molding liquid at the target size 1.

[0074] In one embodiment of the invention, the resolution is preferably 600 dpi or higher, more preferably 600 dpi or higher and 1200 dpi or lower. Even with the same amount of molding liquid, by increasing the resolution, the distance between adjacent droplets becomes closer, making it easier for them to merge. The stronger cohesion between droplets increases the bending strength of the molded object.

[0075] Regarding resolution, for example, the resolution in the main scanning direction can be adjusted by controlling the ejection frequency and the scanning speed of the nozzle. Furthermore, the resolution in the sub-scanning direction can be adjusted by moving the nozzle a required distance in a direction perpendicular to the main scanning direction during each scan.

[0076] In one embodiment of the present invention, when cleaning fluid is applied to the nozzle surface of the nozzle used for cleaning the sprayed styling liquid, the pressure applied to the nozzle is controlled to be 0 mmAq or higher. During cleaning and maintenance, by controlling the pressure applied to the nozzle to be 0 mmAq or higher, it is possible to prevent the cleaning fluid from entering the nozzle and causing the styling liquid inside the nozzle to mix with the cleaning fluid, thereby preventing the loss of styling liquid properties and unstable styling liquid spraying.

[0077] When the cleaning fluid is applied to the nozzle surface of the nozzle used to clean the sprayed styling liquid, the pressure applied to the nozzle is preferably 0 mmol / L or more and 25 mmol / L or less.

[0078] As a method to control the pressure applied to the nozzle to be above 0 mmol / L and below 25 mmol / L, for example, a pump can be used to control the pressure inside the tank supplying the molding liquid.

[0079] There are no particular restrictions on the type of cleaning solution; it can be selected appropriately depending on the purpose. Examples include water-based or organic solvent-based cleaning solutions. In particular, using the same organic solvent as that used in the modeling liquid as the cleaning solution can reduce the risk of changes in the physical properties of the modeling liquid due to color mixing.

[0080] In one embodiment of the invention, it is preferable that the time for the cleaning liquid to reach the nozzle surface is 1 second or more and 2 seconds or less. According to this embodiment, it has the advantage of being able to remove powder adhering to the nozzle surface without causing color mixing.

[0081] The molding liquid of the present invention is a liquid composition used to impart to a powder layer containing inorganic particles when manufacturing shaped objects.

[0082] The creation of the object is carried out by a creation object manufacturing method, which includes a powder layer forming step to form a powder layer containing inorganic particles, a molding liquid application step to apply a molding liquid to the powder layer, and a stacking step to form a stacked object by sequentially repeating the powder layer forming step and the molding liquid application step.

[0083] The manufacture of the molded object is preferably carried out by a molded object manufacturing method. In addition to the above-mentioned lamination process, the molded object manufacturing method also includes a heating process to form a solidified material by heating the laminated body, a residual powder removal process to remove the residual powder adhering to the solidified material to obtain a green body, a drying process to dry the green body to remove the liquid components remaining in the green body, a degreasing process to heat the green body to remove the resin and the like from the molded liquid to obtain a degreased body, a sintering process to heat the degreased body to obtain a sintered body, and a post-treatment process to perform post-treatment on the sintered body.

[0084] In this invention, the term "shape" refers to a general term for three-dimensional objects that maintain a certain three-dimensional shape. For example, it can be a solidified material or a structure derived from a solidified material. Specifically, it refers to the concepts of solidified material, green body, degreased body, and sintered body.

[0085] Furthermore, in this invention, "powder" can also be referred to as "powder" or "powder material." "Modeling liquid" can also be referred to as "curing liquid" or "reaction liquid." Furthermore, "cured product" can also be referred to as "hardened product." Additionally, three-dimensional shapes formed by layering cured products are sometimes also called "green body," "sintered body," "formed body," or "shape." Products obtained by degreasing the "green body" through heat treatment are sometimes also called "degreased body." "Green body" and "degreased body" can be collectively referred to as "sintering precursor."

[0086] The molding liquid of the present invention contains resin, organic solvent and surfactant, and may also contain other ingredients as needed.

[0087] <Resin>

[0088] The molding liquid contains a resin having structural units represented by the following structural formula (1).

[0089]

Chemical Formula 1

[0090]

[0091] - Resin having structural units represented by structural formula (1) -

[0092] A resin having structural units represented by structural formula (1) is contained in a powder layer by incorporating a molding liquid into the powder layer containing inorganic particles. Through a suitable heating process based on the resin's softening point, the inorganic particles in the area where the molding liquid is applied adhere to each other, functioning as an adhesive, thus forming a cured product or a pre-sintered product derived from the cured product. These pre-sintered products, made from resins having structural units represented by structural formula (1) that impart flexibility, have improved flexural strength. The term "structural unit" refers to a portion of the structure in a resin derived from one or more polymeric compounds.

[0093] Furthermore, the resin having structural units represented by structural formula (1) exhibits excellent thermal decomposition properties. Therefore, it can be properly removed during the degreasing process, resulting in an increased density of the sintered body manufactured in the subsequent sintering process. Thus, when metal particles are used as the material for forming the object, sintering is a prerequisite or a preferred sintering material, the effect is significant. Specifically, when the temperature increases from 30°C to 550°C...

[0094] When the resin having the structural unit represented by structural formula (1) is thermally decomposed, it preferably decomposes by 95% or more by mass, more preferably by 97% or more by mass. "Resin thermal decomposition" refers to the random decomposition of the main chain or the depolymerization of the molecular chain ends, and the resin is removed by vaporization, oxidative decomposition, combustion, etc. Furthermore, thermal decomposition can be measured using a TG-DTA (differential thermal / thermogravimetric analysis) device. Specifically, the temperature is increased from 30°C to 550°C at a rate of 10°C / min in an air or nitrogen atmosphere, and after reaching 550°C, it is held at that temperature for 2 hours, and the weight loss rate before and after the temperature increase is measured.

[0095] Furthermore, the resin having structural units represented by structural formula (1) has improved solubility in organic solvents due to the hydrophobicity of the structural units represented by structural formula (1). Therefore, when the modeling liquid contains an organic solvent, the resin having structural units represented by structural formula (1) can improve solubility. Consequently, the viscosity of the modeling liquid can be reduced, for example, by appropriately spraying the modeling liquid using an inkjet method. Moreover, the resin having structural units represented by structural formula (1) is preferably soluble in organic solvents and insoluble in water.

[0096] The glass transition temperature Tg of the resin having the structural unit represented by structural formula (1) is preferably 0°C or higher, more preferably 10°C or higher, and even more preferably 20°C or higher. It is preferably 100°C or lower, more preferably 90°C or lower, and even more preferably 80°C or lower.

[0097] The resin having structural units represented by structural formula (1) preferably has a softening point of 70°C or higher, more preferably 80°C or higher, and even more preferably 90°C or higher. It is preferably 150°C or lower, more preferably 140°C or lower, and even more preferably 130°C or lower.

[0098] The number-average molecular weight Mn of the resin having the structural unit represented by structural formula (1) is preferably 5,000 or more and 50,000 or less, more preferably 10,000 or more and 30,000 or less. When the number-average molecular weight Mn is within the above range, it is possible to simultaneously achieve improved strength and molding accuracy, reduced viscosity of the molding liquid, and increased resin content in the molding liquid.

[0099] The resin having structural units represented by structural formula (1) can be either a resin having structural units other than structural formula (1) or a resin not having structural units other than structural formula (1). As a structural unit represented by a structural unit other than structural formula (1), for example, it is preferred to have a structural unit represented by the following structural formula (3) and / or a structural unit represented by the following structural formula (4).

[0100]

Chemical Formula 2

[0101]

[0102]

Chemical Formula 3

[0103]

[0104] In addition to the structural unit represented by structural formula (1), the resin also has the structural unit represented by structural formula (3), which can improve the flexural strength of the cured product and the green body derived from the cured product before sintering.

[0105] Furthermore, since the structural unit represented by structural formula (3) is also hydrophobic as the structural unit represented by structural formula (1), the solubility of the resin in organic solvents is improved.

[0106] From these perspectives, in the resin, the total amount of structural units represented by structural formula (1) and structural units represented by structural formula (3) relative to the total amount of structural units represented by structural formula (1), structural units represented by structural formula (3), and structural units represented by structural formula (4) is preferably 60 mol% or more, more preferably 65 mol% or more, further preferably 70 mol% or more, particularly preferably 75 mol% or more, and most preferably 80 mol% or more. The same applies when the resin does not have structural units represented by structural formula (3) and / or structural formula (4); the amount of the absence of such structural units is taken as 0 when calculating the above proportions.

[0107] In addition to the structural unit represented by structural formula (1), the resin also has a structural unit represented by structural formula (4). The hydroxyl groups in the structural unit represented by structural formula (4) can improve the affinity with inorganic particles in the powder layer to which the molding liquid is applied. This further improves the flexural strength of the cured product and the green body derived from the cured product before sintering, and also further improves the density of the pre-sintering product and the density of the post-sintering product. From these viewpoints, the amount of the structural unit represented by structural formula (4) in the resin, relative to the total amount of the structural units represented by structural formula (1), structural units represented by structural formula (3), and structural units represented by structural formula (4), is preferably 5 mol% or more, more preferably 15 mol% or more, and even more preferably 25 mol% or more.

[0108] However, since the structural unit represented by structural formula (4) is hydrophilic, when the proportion of the structural unit represented by structural formula (4) increases, the presence of organic solvents in the molding liquid will inhibit the improvement of the solubility of the resin having the structural unit represented by structural formula (1) and inhibit the decrease of the viscosity of the molding liquid. Therefore, the amount of the structural unit represented by structural formula (4) in the resin relative to the total amount of the structural units represented by structural formula (1), structural units represented by structural formula (3), and structural units represented by structural formula (4) is preferably 40 mol% or less, more preferably 35 mol% or less, further preferably 30 mol% or less, particularly preferably 25 mol% or less, and most preferably 20 mol% or less. This also applies to the case where the resin does not have the structural unit represented by structural formula (3), where the amount of the non-structural unit is taken as 0, and the above proportion can be calculated.

[0109] Specific examples of resins having structural units represented by structural formula (1) include, for example, polyvinyl acetate resin, partially saponified polyvinyl acetate resin, and polyvinyl butyral resin. Among these, from the viewpoint of reducing the viscosity of the molding liquid, polyvinyl acetate resin and partially saponified polyvinyl acetate resin are preferred.

[0110] Here, "partially saponified polyvinyl acetate resin" refers to a partially saponified polyvinyl acetate resin in which the amount of structural units represented by structural formula (1) is 75 mol% or more relative to the total amount of structural units represented by structural formula (1) and structural units represented by structural formula (4), preferably 80 mol% or more. These resins can be used alone or in combination of two or more. In addition, either commercially available or synthetic resins can be used.

[0111] Polyvinyl acetate resin is a resin having structural units represented by structural formula (1), substantially not having structural units represented by structural formula (3), and structural units represented by structural formula (4).

[0112] Partially saponified polyvinyl acetate resin is a resin having structural units represented by structural formula (1) and structural units represented by structural formula (4), but not substantially having structural units represented by structural formula (3).

[0113] Polyvinyl butyral resin is a resin having structural units represented by structural formula (1) and structural units represented by structural formula (3), or a resin having structural units represented by structural formula (1), structural units represented by structural formula (3) and structural units represented by structural formula (4).

[0114] The term "partially saponified polyvinyl acetate resin" refers to a resin obtained by partially saponifying polyvinyl acetate resin. Furthermore, in the partially saponified polyvinyl acetate resin, the amount of the structural unit represented by structural formula (4) relative to the total amount of the structural units represented by structural formula (1) and structural units represented by structural formula (4) is preferably 40 mol% or less, more preferably 35 mol% or less, even more preferably 30 mol% or less, particularly preferably 25 mol% or less, and most preferably 20 mol% or less. In other words, the degree of saponification of the partially saponified polyvinyl acetate resin is preferably 40 or less, more preferably 35 or less, even more preferably 30 or less, particularly preferably 25 or less, and most preferably 20 or less.

[0115] The resin content of the structural unit represented by structural formula (1) relative to the total amount of the molding liquid is preferably 5% by mass or more, more preferably 7% by mass or more, further preferably 10% by mass or more, and particularly preferably 11% by mass or more. Furthermore, it is preferably 30% by mass or less, more preferably 25% by mass or less, and further preferably 20% by mass or less. When the resin content is 5% by mass or more, the flexural strength of the cured product and the molded product derived from the cured product before sintering is further improved. When the resin content is 30% by mass or less, the viscosity of the molding liquid can be further reduced; for example, the molding liquid can be appropriately sprayed by inkjet printing.

[0116] A resin whose total amount of structural units represented by structural formula (1) and structural units represented by structural formula (3) is 95 mol% or more relative to the total amount of structural units represented by structural formula (1), structural units represented by structural formula (3), and structural units represented by structural formula (4) can have a high content (15% or more by mass or 20% or more by mass relative to the total amount of the molding liquid) because it can improve the solubility of the resin in organic solvents and reduce the viscosity of the molding liquid. As a result, the flexural strength of the cured product and the molded product derived from the cured product before sintering is further improved.

[0117] The amount (mol%) of structural units represented by each structural formula in the resin can be determined, for example, by the polyvinyl alcohol test method described in JIS-K6276-1994.

[0118] In the molding liquid of the present invention, in addition to the resin having the structural unit represented by structural formula (1), it may also contain, as needed, a resin having the structural unit represented by the following structural formula (2) or a polyvinyl alcohol resin.

[0119] - Resin having structural units represented by structural formula (2) -

[0120] [Chemical Formula 4]

[0121]

[0122] A resin having structural units represented by structural formula (2) is contained in a powder layer by incorporating a molding liquid into the powder layer containing metal particles. Through a suitable heating process based on the resin's softening point, the metal particles in the area in which the molding liquid is applied adhere to each other, functioning as an adhesive, thus forming a cured product or a pre-sintered product derived from the cured product. These pre-sintered products are formed from resins with a five-membered ring lactam structure that has a high affinity for metal, consisting of structural units represented by structural formula (2). Therefore, the metal particles are firmly bonded together, improving flexural strength.

[0123] Furthermore, if the heating curve is properly controlled, the resin having the structural unit represented by structural formula (2) exhibits excellent thermal decomposition properties. Therefore, it can be appropriately removed during the degreasing process, increasing the density of the sintered body manufactured through the subsequent sintering process. Thus, when metal particles are used as the material for forming the molded object, with sintering as a prerequisite or preferred, the effect is significant. Specifically, the resin having the structural unit represented by structural formula (2) preferably undergoes thermal decomposition of 95% by mass or more, more preferably 97% by mass or more, when heated from 30°C to 550°C.

[0124] However, the resin having structural units represented by structural formula (2) forms a cross-linked structure under temperature conditions (e.g., heating conditions above 160°C), which sometimes inhibits the effect of high thermal decomposition. Therefore, when metal particles are used as the material for forming the molded object, based on the viewpoint of ease of processing, the resin having structural units represented by structural formula (1) is sometimes preferred over the resin having structural units represented by structural formula (2).

[0125] Furthermore, the resin having the structural unit represented by structural formula (2) has a five-membered ring lactam structure, which improves its solubility in certain organic solvents (mainly polar solvents). Consequently, the viscosity of the molding liquid can be further reduced, for example, the molding liquid can be appropriately sprayed by inkjet printing. In addition, when the resin having the structural unit represented by structural formula (2) is used in combination with component 1 (cyclic esters (lactones) and component 2 (diol diethers, etc.) as organic solvents, the viscosity of the molding liquid can be further reduced. In this way, the viscosity of the molding liquid can be reduced, and therefore, the resin having the structural unit represented by structural formula (2) can have a high content in the molding liquid (for example, more than 15% by mass relative to the total amount of the molding liquid). As a result, the flexural strength of the cured product and the molded product derived from the cured product before sintering is further improved.

[0126] The resin having the structural unit represented by structural formula (2) preferably has a softening point of 70°C or higher, more preferably 80°C or higher, and even more preferably 90°C or higher. Furthermore, it is preferably 180°C or lower, more preferably 170°C or lower, and even more preferably 160°C or lower.

[0127] The number-average molecular weight Mn of the resin having the structural unit represented by structural formula (2) is preferably 3,000 or more and 50,000 or less, more preferably 5,000 or more and 40,000 or less. When the number-average molecular weight Mn is within the above range, it is possible to simultaneously achieve improvements in strength and molding accuracy, reduction in molding liquid viscosity, and increase in resin concentration in the molding liquid.

[0128] Specific examples of resins having structural units represented by structural formula (2) include polyvinylpyrrolidone resin, etc. Furthermore, either commercially available or synthetic resins can be used.

[0129] -Polyvinyl alcohol resin-

[0130] Polyvinyl alcohol resin is contained in a powder layer containing inorganic particles by applying a molding liquid to the powder layer. Through a suitable heating process based on the softening point of the resin, the inorganic particles in the area where the molding liquid is applied adhere to each other, acting as an adhesive to form a cured product or a green body derived from the cured product before sintering.

[0131] In addition to polyvinyl alcohol resin, polyvinyl alcohol resin also includes polymers or their saponifications that have vinyl alcohol as a structural unit.

[0132] The average degree of polymerization and saponification of polyvinyl alcohol can be adjusted by appropriately adjusting the amount of vinyl acetate used as a raw material.

[0133] The average degree of polymerization of the polyvinyl alcohol resin (as determined according to JIS K6726) is preferably 100 or more and 2,000 or less, more preferably 100 or more and 1,000 or less. If the average degree of polymerization is too high, the melt viscosity will be too high, and the molding or formability will tend to deteriorate. On the other hand, if the average degree of polymerization is too low, the molded or shaped article tends to have insufficient mechanical strength.

[0134] The degree of saponification of polyvinyl alcohol resin (as determined according to JIS K6726) is not particularly limited, and can be appropriately selected according to the intended use, solubility, moisture resistance, etc. It is preferred to be 0 mol% or more and 100 mol% or less, and compared with the fully saponified type, the partially saponified type with 80 mol% or less is more preferred.

[0135] <Organic solvents>

[0136] Organic solvents are liquid components used to maintain the modeling liquid in a liquid state at room temperature.

[0137] Furthermore, the styling liquid is preferably a non-aqueous styling liquid containing an organic solvent. The term "non-aqueous styling liquid" means that the liquid component of the styling liquid contains an organic solvent, and the component with the largest mass in the liquid component is the organic solvent. More specifically, the content of the organic solvent is preferably 90% by mass or more, and more preferably 95% by mass or more, relative to the content of the liquid component in the styling liquid.

[0138] If the molding liquid is non-aqueous, its solubility is improved, especially in resins with structural units represented by structural formula (1), and its viscosity is reduced. Furthermore, non-aqueous molding liquids can sometimes be considered, for example, substantially water-free molding liquids. Therefore, the molding liquid can be used even when the material constituting the inorganic metal particles is a highly reactive metal, in other words, a water-restricted material (e.g., aluminum, zinc, magnesium, or their alloys). For example, aluminum forms an aluminum hydroxide film when in contact with water; therefore, a high water content in the molding liquid can lead to a low sintering density in the sintered body, but this problem can be suppressed by using an water-free molding liquid. As another example, aluminum produces hydrogen when in contact with water, which presents a difficult-to-handle problem, but this problem can be suppressed by using an water-free molding liquid.

[0139] Examples of organic solvents include n-octane, m-xylene, solvent naphtha, diisobutyl ketone, 3-heptanone, 2-octanone, acetylacetone, butyl acetate, amyl acetate, n-hexyl acetate, n-octyl acetate, ethyl butyrate, ethyl valerate, ethyl caprylate, ethyl octoate, ethyl acetoacetate, ethyl 3-ethoxypropionate, diethyl oxalate, diethyl malonate, diethyl succinate, diethyl adipate, di-2-ethylhexyl maleate, triacetin, glyceryl tartrate, propylene glycol monomethyl ether acetate, ethylene glycol monobutyl ether acetate, dibutyl ether, 1,2-dimethoxybenzene, 1,4-dimethoxybenzene, diethylene glycol monobutyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, ethyl 2-methoxy-1-methylethyl acetate, γ-butyrolactone, propylene carbonate, cyclohexanone, and butyl cellosolve, etc. These can be used individually or in combination of two or more.

[0140] When using a resin having structural units represented by structural formula (1), there are no particular limitations on the organic solvents used in combination, and they can be appropriately selected according to the purpose. However, it is preferable to use an organic solvent with at least one structure selected from, for example, a group consisting of alkoxy groups, ether bonds, and ester bonds. More preferably, an organic solvent having ether bonds is used, and even more preferably, an alkylene glycol dialkyl ether compound is used. When using these organic solvents, the solubility of the resin having structural units represented by structural formula (1) is further improved, and consequently, the viscosity of the modeling liquid is further reduced, for example, so that the modeling liquid can be appropriately sprayed out by inkjet printing.

[0141] The term "alkylene glycol dialkyl ether compound" is composed of R1-(O-R2). m -OR3 indicates that R1 and R3 each independently represent an alkyl group having 1 to 5 carbon atoms, which can be straight-chain or branched, preferably having 1 or 2 carbon atoms. R2 represents an alkylene group having 2 to 5 carbon atoms, which can be straight-chain or branched, preferably having 2 or 3 carbon atoms. m represents an integer of 1 to 5, more preferably 2 or 3.

[0142] Specific examples of alkylene glycol dialkyl ether compounds include diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, diethylene glycol ethyl methyl ether, and diethylene glycol butyl methyl ether. Among these, diethylene glycol dimethyl ether and triethylene glycol dimethyl ether are preferred, and triethylene glycol dimethyl ether is more preferred.

[0143] When using a resin having structural units represented by structural formula (2), it is preferable to use a polar solvent in combination. Specifically, it is preferable to use at least one of component 1 selected from the group consisting of cyclic esters (lactones), cyclic ketones, and alkylene glycol monoalkyl ethers, and more preferably, in addition to using at least one selected from component 1, at least one selected from component 2 consisting of dialkylene glycol dialkyl ethers. When using these organic solvents, the solubility of the resin having structural units represented by structural formula (2) is further improved, and consequently, the viscosity of the modeling liquid can be further reduced, for example, the modeling liquid can be appropriately sprayed by inkjet. From the viewpoint of further improving the solubility of the resin having structural units represented by structural formula (2), component 1 is preferably a group consisting of cyclic esters (lactones) and cyclic ketones.

[0144] When a resin having structural units represented by structural formula (2) is used, and at least one of the components selected from Component 1 and at least one of the components selected from Component 2 is used as an organic solvent, the mass ratio (Component 1 / Component 2) of the total amount of Component 1 to the total amount of Component 2 is preferably 60 / 40 to 100 / 0. When the mass ratio (Component 1 / Component 2) is 60 / 40 to 100 / 0, the solubility of the resin having structural units represented by structural formula (2) is further improved, and consequently, the viscosity of the molding liquid can be further reduced.

[0145] Specific examples of component 1, which is a collection of cyclic esters (lactones), cyclic ketones, and alkylene glycol monoalkyl ethers, include, for example, γ-butyrolactone, propylene carbonate, and cyclohexanone.

[0146] Specific examples of component 2, which is a group composed of alkylene glycol dialkyl ethers, include, for example, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, diethylene glycol ethyl methyl ether, and diethylene glycol butyl methyl ether. Among these, diethylene glycol dimethyl ether and triethylene glycol dimethyl ether are preferred.

[0147] The so-called "alkylene glycol monoalkyl ethers" are composed of R4-(O-R5). n -OH indicates that R4 represents an alkyl group having 1 to 5 carbon atoms, which can be straight-chain or branched. R5 represents an alkylene group having 2 to 5 carbon atoms, which can be straight-chain or branched. n represents an integer from 1 to 5.

[0148] When it is desired to further reduce the viscosity of the molding liquid, the use of a resin with structural units represented by structural formula (2) instead of a resin with structural units represented by structural formula (1) is greatly affected by the types of organic solvents used in combination, and the aforementioned organic solvents (component 1 and component 2) need to be used selectively. Therefore, from the viewpoint of expanding the range of materials to be selected in the manufacture of molding liquid, it is preferable to use a resin with structural units represented by structural formula (1) compared to a resin with structural units represented by structural formula (2).

[0149] The viscosity of the organic solvent is preferably low, specifically, at 25°C, preferably 5 mPa·s or more and 50 mPa·s or less, more preferably 8 mPa·s or more and 30 mPa·s or less. When the viscosity of the organic solvent is within the above range, it is also easier to reduce the viscosity of the molding liquid containing the organic solvent, so that the molding liquid is stably sprayed from the nozzle or other molding liquid application device. Since the correct molding liquid is sprayed, the bending strength of the cured product and the green body derived from the cured product is further improved, and the dimensional accuracy is further improved.

[0150] Viscosity can be measured according to, for example, JIS K7117.

[0151] The boiling point of the organic solvent is preferably high, specifically, preferably 150°C or higher, and more preferably 180°C or higher. If the organic solvent has a high boiling point when the modeling liquid is sprayed using methods such as inkjet printing, drying of the modeling liquid at or near the nozzle can be suppressed, and nozzle clogging caused by resin precipitation can be prevented. There are no particular limitations on the type of high-boiling-point organic solvent; it can be appropriately selected depending on the purpose. Examples include, for instance, γ-butyrolactone (boiling point: 204°C) and propylene carbonate (boiling point: 242°C).

[0152] ℃), cyclohexanone (boiling point: 155.6℃), diethylene glycol dimethyl ether (boiling point: 162℃), triethylene glycol dimethyl ether (boiling point: 216℃), etc.

[0153] The content of organic solvent relative to the total amount of molding liquid is preferably 60% by mass or more and 95% by mass or less, more preferably 70% by mass or more and 95% by mass or less. When the content of organic solvent is 60% by mass or more and 95% by mass or less, the solubility of the resin is further improved, and consequently, the viscosity of the molding liquid can be further reduced. For example, the molding liquid can be appropriately sprayed out by inkjet printing. In addition, the drying of the molding liquid in the molding liquid imparting device can be suppressed, and a molding liquid with excellent spraying stability can be provided.

[0154] The mass ratio of organic solvent content to resin content (organic solvent / resin) is preferably 75 / 25 or higher and 95 / 5 or lower. When the mass ratio (organic solvent / resin) is 75 / 25 or higher, the solubility of the resin is further improved, and consequently, the viscosity of the molding liquid can be further reduced. For example, the molding liquid can be appropriately sprayed by inkjet printing. In addition, if the mass ratio (organic solvent / resin) is 95 / 5 or lower, the flexural strength of the cured product and the molded product derived from the cured product before sintering is further improved.

[0155] The total content of organic solvents and resins relative to the total amount of the styling liquid is preferably 90% by mass or more, more preferably 95% by mass or more, even more preferably 99% by mass or more, and particularly preferably 99.5% by mass or more. Furthermore, it may substantially contain no components other than organic solvents and resins. It should be noted that "substantially containing no components other than organic solvents and resins" means that no components other than organic solvents and resins are actively used as materials in the manufacture of the styling liquid, or that the content of components other than organic solvents and resins in the styling liquid is below the detection limit when measured using known and commonly used techniques.

[0156] When the total content of organic solvents and resins is 90% or more by mass relative to the total amount of molding liquid, the increased resin content in the molding liquid further improves the flexural strength of molded products such as cured products and green bodies derived from cured products. Furthermore, when the content of components other than organic solvents and resins (such as materials insoluble in the molding liquid, like metal particles) is reduced or substantially absent, the viscosity of the molding liquid is lowered, improving its spraying stability and storage stability.

[0157] <surfactants>

[0158] The addition of surfactants increases the powder contact angle θ between the molding liquid and inorganic particles, thereby improving the dimensional accuracy of the resulting molded objects.

[0159] As a surfactant, at least one of, for example, fluorinated surfactants and silicone surfactants is preferred. By using such fluorinated surfactants and silicone surfactants in the molding liquid, the seepage of the molding liquid into non-molding areas can be suppressed, and molded objects with target dimensional accuracy can be stably obtained.

[0160] Commercially available products can be used as such fluorinated surfactants, such as Surflon S-693 (manufactured by AGC Sei Chemical Co., Ltd.) and KF-353 (manufactured by Shin-Etsu Chemical Co., Ltd.).

[0161] Commercially available products can be used as such silicone surfactants, such as Silface SAG020 (manufactured by Nichishin Chemical Co., Ltd.).

[0162] The surfactant content relative to the total amount of the modeling liquid is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, even more preferably 0.05% by mass or more, more preferably 0.1% by mass or more, and particularly preferably 0.3% by mass or more. Furthermore, it is preferably 5% by mass or less, more preferably 3% by mass or less, even more preferably 1% by mass or less, and particularly preferably 0.5% by mass or less.

[0163] When the content of surfactant is within the above range, the contact angle θ between the molding liquid and inorganic particles can be increased, thereby improving the dimensional accuracy of the molded object.

[0164] <Other Ingredients>

[0165] Other ingredients are not particularly restricted and can be selected appropriately according to the purpose. Examples include water, desiccant, viscosity modifier, penetrant, defoamer, pH adjuster, preservative, mildew inhibitor, colorant, preservative, and stabilizer.

[0166] -water-

[0167] The styling liquid is substantially water-free. In this invention, "substantially water-free" means that the water content relative to the total amount of the styling liquid is 10% by mass or less, preferably 5% by mass or less, more preferably 3% by mass, further preferably 1% by mass or less, and particularly preferably the styling liquid is water-free. When the styling liquid is substantially water-free, the solubility of the aforementioned resin is further improved, and consequently, the viscosity of the styling liquid can be further reduced. In addition, the formation of hydrogels containing a large amount of water around the resin is suppressed, thereby suppressing the increase in the viscosity of the styling liquid. Therefore, for example, the styling liquid can be appropriately sprayed by inkjet printing. Furthermore, "substantially water-free" means that water is not actively used as a raw material in the production process of the styling liquid, or the water content in the styling liquid is below the detection limit when detected using known and commonly used techniques.

[0168] Furthermore, since the molding solution is essentially water-free, it can also be used for materials that constitute inorganic particles, which are highly reactive metals; in other words, it is suitable for water-restricted materials (e.g., aluminum, zinc, magnesium, or their alloys). For example, aluminum forms an aluminum hydroxide film when it comes into contact with water; therefore, a high water content in the molding solution can lead to low sintering density in the sintered body, but this problem can be suppressed by using an anhydrous molding solution. As another example, aluminum produces hydrogen when it comes into contact with water, which presents a difficult-to-handle problem, but this problem can be suppressed by using an anhydrous molding solution.

[0169] <Manufacturing Method of Styling Liquid>

[0170] There are no particular restrictions on the method of manufacturing the styling liquid. It can be selected appropriately according to the purpose. Examples include mixing the above materials and stirring.

[0171] <Inorganic Particles>

[0172] Inorganic particles can be selected appropriately as long as they have the form of powder or even particles, without any particular restrictions. Examples include metals, ceramics, carbon, sand, and magnetic materials. From the perspective of obtaining three-dimensional objects with extremely high strength, metals and ceramics that can be sintered in the final process are preferred.

[0173] Examples of ceramics include oxides, carbides, nitrides, and hydroxides.

[0174] Examples of oxides include metal oxides. Examples of metal oxides include silicon dioxide (SiO2), aluminum oxide (Al2O3), zirconium oxide (ZrO2), and titanium dioxide (TiO2). These can be used alone or in combination of two or more.

[0175] As metal particles, these are particles containing metal particles as a constituent material. There are no particular limitations on the constituent materials of the metal particles as long as they contain metal; they may also contain materials other than metal, but it is preferred that the main material is metal. "Main material is metal" means that the mass of the metal contained in the metal particles is 50% or more by mass relative to the mass of the metal particles, preferably 60% or more by mass, more preferably 70% or more by mass, further preferably 80% or more by mass, and particularly preferably 90% or more by mass.

[0176] Metals that can be used as constituent materials for metal particles include, for example, magnesium (Mg), aluminum (Al), titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), yttrium (Y), zirconium (Zr), niobium (Nb), molybdenum (Mo), lead (Pd), silver (Ag), indium (In), tin (Sn), tantalum (Ta), tungsten (W), neodymium (Nd), or alloys of these metals. These can be used alone or in combination of two or more. Among these, stainless steel (SUS), iron (Fe), copper (Cu), silver (Ag), titanium (Ti), magnesium (Mg), zinc (Zn), aluminum (Al), or alloys of these metals are preferred, aluminum, zinc, magnesium, or alloys of these metals are more preferred, and aluminum alloys are particularly preferred.

[0177] As an aluminum alloy, examples include AlSi. 10 Mg, AlSi 12 AlSi7Mg 0.6, AlSi3Mg, AlSi9Cu3, Scalmalloy, ADC 12 AlSi3, etc.

[0178] There are no particular limitations on the metal particles, and they can be manufactured using methods already known. Examples of methods for manufacturing metal particles include, for instance, pulverization by applying compression, impact, or friction to a solid to refine it; atomization by spraying molten metal to obtain rapidly cooled powder; precipitation by causing components dissolved in a liquid to precipitate; and gas-phase reaction by vaporization followed by recrystallization. Among these, atomization is preferred from the viewpoint of obtaining spherical particles with minimal particle size variation. There are no particular limitations on the atomization method; it can be appropriately selected depending on the purpose. Examples include aqueous atomization, gas-phase atomization, centrifugal atomization, and plasma atomization.

[0179] Commercially available metal granules can also be used. Examples of commercially available products include pure Al (manufactured by Toyo Aluminum Co., Ltd., A1070-30BB), pure titanium (manufactured by Osaka Titanium Technologies Co., Ltd.), SUS316L (manufactured by Sanyo Special Steel Co., Ltd., trade name: PSS316L), and AlSi. 10 Mg (manufactured by Toyo Aluminium Co., Ltd.), Si 10 MgBB), SiO2 (manufactured by Tokuyama Corporation, trade name: EXCELICA SE-15K), AlO2 (manufactured by Taimei Chemical Industry Co., Ltd., trade name: TAIMICRON TM-5D), ZrO2 (manufactured by Tosoh Corporation, trade name: TZ-B53), aluminum powder (manufactured by Toyo Aluminum Co., Ltd., ALSI3-30B), etc.

[0180] There are no particular limitations on the volume average particle size of the metal particles, and it can be appropriately selected according to the purpose. For example, it is preferable to be 2 μm or more and 100 μm or less, and more preferably 8 μm or more and 50 μm or less. When the volume average particle size of the metal particles is 2 μm or more, the aggregation of metal particles can be suppressed, thereby suppressing the reduction in manufacturing efficiency and the reduction in the processability of metal particles. Furthermore, if the volume average particle size of the metal particles is 100 μm or less, the reduction in the number of joints between metal particles and the increase in the porosity can be suppressed, thereby suppressing the reduction in the strength of the molded object.

[0181] There are no particular restrictions on the particle size distribution of metal particles; it can be appropriately selected according to the purpose, with a preferred particle size distribution having a sharp peak shape.

[0182] The volume average particle size and particle size distribution of metal particles can be measured using known particle size measuring devices, such as particle size distribution measuring devices (Microtrac MT3000II series, manufactured by Microtrac Bell Co., Ltd.).

[0183] A known method for manufacturing shaped objects uses metal particles having a metal substrate and a resin-coated substrate. A liquid is applied to the metal particles, allowing them to function as a binder in the resin. However, in this invention, the molding liquid contains a resin that also functions as a binder. Therefore, the surface of the metal particles does not need to be coated with resin. By using metal particles whose surfaces are not coated with resin, for example, even in powder areas where no molding liquid is applied (i.e., non-molding areas), it is possible to prevent the resin coating process during heating from causing the metal particles to adhere together and form an undesirable cured product.

[0184] Here, "surface not coated with resin" means, for example, that the ratio of the resin surface area to the metal particle surface area (surface coating rate) is less than 15%, or the surface coating rate can be 0%. The surface coating rate can be determined, for example, by acquiring a photograph of the metal particle and, within the area captured in the planar photograph, by measuring the area ratio (%) of the resin-coated portion relative to the total surface area of ​​the metal particle. Furthermore, the determination of the resin-coated portion can be achieved using methods such as elemental mapping in energy-dispersive X-ray spectrophotometry (EDS).

[0185] <Powders containing inorganic particles>

[0186] The aforementioned inorganic particles are used as a powder containing an aggregate of multiple inorganic particles, and a modeling liquid is applied to the powder layer to create a model.

[0187] In addition to inorganic particles, powders can also contain other ingredients as needed.

[0188] Other components include fillers, leveling agents, sintering aids, and polymer resin particles.

[0189] Fillers are effective materials that adhere to the surface of inorganic particles or fill the voids between them. By using fillers, for example, the flowability of powder can be improved, the number of joints between inorganic particles can be increased, and voids can be reduced, thereby improving the strength and dimensional accuracy of the molded object.

[0190] Leveling agents are effective materials for controlling the wettability of powder layer surfaces. By using leveling agents, for example, the penetration of molding liquid into powder layers can be improved, thereby increasing the strength of the molded object.

[0191] Sintering aids are effective materials used to improve sintering efficiency when sintering molded objects. By using sintering aids, for example, the strength of the molded object can be increased, the sintering temperature can be reduced, and the sintering time can be shortened.

[0192] Polymer resin particles are effective materials that adhere to the surface of inorganic particles, also known as organic additives. There are no particular limitations on the average particle size of the polymer resin particles; they can be appropriately selected according to the purpose, preferably 0.1 μm or more and 10 μm or less, more preferably 0.1 μm or more and 1 μm or less.

[0193] (fabrication kit)

[0194] The styling kit of the present invention includes the styling liquid and inorganic particles of the present invention, and may also include other components such as a powder remover, as needed. Furthermore, in the styling kit, the inorganic particles and styling liquid can exist in separate, independent states, and are not limited to a form in which the styling liquid storage section for storing the styling liquid and the inorganic particle storage section for storing the inorganic particles are integrated. For example, the styling kit also includes cases where the styling liquid and inorganic particles are stored in separate, independent storage sections, and where the inorganic particles and styling liquid are used together, substantially guiding the use of both inorganic particles and styling liquid.

[0195] As inorganic particles in styling kits, the same inorganic particles used in styling liquids can be used.

[0196] The inorganic particles are metallic particles, preferably containing at least one selected from aluminum, zinc, magnesium, and their alloys. Preferably, the surface of the inorganic particles is not coated with resin.

[0197] (Methods for manufacturing sculpted objects)

[0198] The method for manufacturing the model of the present invention includes a powder layer forming step for forming a powder layer containing inorganic particles, a modeling liquid applying step for applying a modeling liquid to the powder layer, and a stacking step for sequentially repeating the powder layer forming step and the modeling liquid applying step to form a stacked model.

[0199] Furthermore, the method for manufacturing the molded object may further include a heating step of heating the laminated material to form a solidified material, a residual powder removal step of removing the powder adhering to the solidified material, i.e., the remaining powder, to obtain a green body, a drying step of drying the green body to remove the liquid components remaining in the green body, a degreasing step of heating the green body to remove the resin and the like from the applied molding liquid to obtain a degreased body, a sintering step of heating the degreased body to obtain a sintered body, and a post-processing step of post-processing the sintered body, etc.

[0200] <Powder Layer Formation Process>

[0201] The powder layer forming process is the process of forming a powder layer containing inorganic particles, which is carried out by a powder layer forming device.

[0202] A powder layer is formed on a support (molding table). There are no particular limitations on the method of placing powder on the support to form a thin powder layer, and it can be appropriately selected according to the purpose. For example, the selective laser sintering method described in Japanese Patent No. 3607300, the method of using a known reverse rotation mechanism (reverse roller), the method of using a brush, roller, scraper or other components to diffuse the powder, the method of using a pressing component to press the powder surface to form a thin layer, and the method of using a known layering molding device, etc.

[0203] When forming a powder layer using a powder layer forming device such as a reverse rotation mechanism (reverse roller), brush, scraper, or pressing component, the following methods can be used, for example.

[0204] That is, powder is placed on a support that can slide and rise along the inner wall of the outer frame (sometimes also called a "molding mold", "hollow cylinder", "cylindrical structure", etc.) using a reverse rotation mechanism (reverse roller), brush, scraper, pressing member, etc. In this case, when using a structure that can rise and fall within the outer frame as the support, the support is positioned slightly below the upper opening of the outer frame (in other words, below only one layer of powder thickness), and powder is placed on the support. As described above, a thin layer of powder can be placed on the support.

[0205] There are no particular limitations on the thickness of the powder layer, and it can be appropriately selected according to the purpose. For example, the average thickness of each layer is preferably 30 μm or more and 500 μm or less, and more preferably 60 μm or more and 300 μm or less.

[0206] When the average thickness is 30 μm or more, applying the molding liquid to the powder increases the strength of the formed solidified material, suppressing potential collapse in subsequent processes such as sintering. Furthermore, when the average thickness is 500 μm or less, applying the molding liquid to the powder improves the dimensional accuracy of the formed solidified material.

[0207] There are no particular restrictions on the average thickness; it can be measured using well-known methods.

[0208] The powder supplied by the powder layer forming device can be stored in the powder storage section. The powder storage section is a container or other component for storing powder, such as a storage tank, bag, card box, can, etc.

[0209] <Forming Liquid Application Process>

[0210] The molding liquid application process is the process of applying molding liquid to the powder layer formed in the powder layer formation process, and it is carried out by a molding liquid application device.

[0211] As a method for applying modeling liquid to a powder layer, a method of spraying the modeling liquid is preferred. There are no particular limitations on the method of spraying the modeling liquid; it can be appropriately selected depending on the purpose, such as the dispenser method, spraying method, inkjet method, etc. Among these, the dispenser method has excellent droplet metering, but a narrow coating area. The spraying method easily forms fine jets, has a wide coating area, and excellent coating properties, but poor droplet metering and the jet stream causes modeling liquid to scatter. Therefore, the inkjet method is preferred. The inkjet method has the advantages of better droplet metering than the spraying method and a wider coating area than the dispenser method, enabling the formation of complex three-dimensional shapes with high precision and efficiency, thus making it very suitable.

[0212] When using inkjet printing, the inkjet applicator, which applies the ink by ejecting the inkjet fluid, has an inkjet head with nozzles for ejecting the inkjet fluid. As the inkjet head, a known inkjet printer inkjet head can be used. Examples of inkjet printer inkjet heads include the RICOH MH / GH SERIES industrial inkjet head manufactured by Ricoh Corporation. Furthermore, examples of inkjet printers include, for instance, the SG7100 manufactured by Ricoh Corporation.

[0213] The styling liquid supplied to the styling liquid applicator can be stored in the styling liquid storage unit. The styling liquid storage unit is a container or other component that holds the styling liquid, such as a storage tank, bag, card holder, or can.

[0214] <Lamination Process>

[0215] The lamination process is a process of forming a laminate by sequentially repeating the powder layer formation process and the molding liquid application process, which is carried out by a lamination device.

[0216] The term "layered structure" refers to a structure formed by multiple layers of powder, each layer having an area for applying a molding liquid. In this case, the structure may or may not contain any three-dimensional objects that maintain a certain shape internally, or it may contain three-dimensional objects that maintain a certain shape internally.

[0217] The lamination process includes a process of placing powder in a thin layer (powder layer forming process) and a process of applying a modeling liquid onto the thin layer (modeling liquid application process). This forms a region for applying the modeling liquid within the powder layer. Furthermore, the lamination process includes a process of placing powder in a thin layer (lamination) on the powder layer, which is the powder layer having the region for applying the modeling liquid, in the same manner as described above (powder layer forming process), and a process of applying the modeling liquid onto the thin layer (modeling liquid application process). This forms a region for applying the modeling liquid within the newly laminated powder layer. At this point, the region for applying the modeling liquid formed in the uppermost laminated powder layer is continuous with the region for applying the modeling liquid in the powder layer below it. As a result, a region for applying the modeling liquid with a thickness of two powder layers is obtained.

[0218] <Heating Process>

[0219] The heating process is a process of heating the laminated material formed in the lamination process to form a solidified material, which is carried out by a heating device.

[0220] The term "curing" refers to maintaining a certain shape. A "cured product" is a three-dimensional structure that retains a certain three-dimensional shape. Furthermore, a cured product refers to a structure that has not undergone a residual powder removal process to remove residual powder that does not constitute a three-dimensional object.

[0221] The heating temperature in the heating process is preferably higher than the softening point of the resin. Thus, the resin functions as an adhesive that binds the inorganic particles in the area to which the molding liquid is applied, forming a cured product and a green body derived from the cured product before sintering.

[0222] As a heating device, there are no particular restrictions, and it can be selected appropriately according to the purpose. For example, dryers, constant temperature and humidity chambers, etc. can be listed.

[0223] <Removal of residual powder process>

[0224] The process of removing residual powder is the process of removing powder adhering to the solidified material, that is, removing residual powder to obtain green body, and is carried out by residual powder removal device.

[0225] The term "green body" refers to a three-dimensional object that maintains a certain three-dimensional shape. It indicates that the object has undergone a process of removing powder that does not constitute a solidified substance, i.e., removing the remaining powder. Preferably, it refers to a three-dimensional object that does not actually have any remaining powder attached to it.

[0226] Furthermore, the residual powder removal process preferably includes at least one process selected from the process of removing residual powder from the solidified material by blowing air and the process of removing residual powder from the solidified material by immersing the solidified material in a removal liquid, and more preferably includes both of the above processes.

[0227] The cured product after the heating process is buried in powder that has not been coated with molding fluid, i.e., in a state of residual powder. When the cured product is removed from this buried state, the residual powder adheres to the surface and interior of the cured product, making it difficult to remove easily. Moreover, this difficulty is even greater when the surface shape of the cured product is complex or the internal structure of the cured product is flow-path shaped. The pre-sintering molded product created using conventional adhesive spraying methods has low strength; therefore, if the airflow pressure of the air supply device is high, there is a concern that the molded product may collapse.

[0228] On the other hand, the cured product formed using the molding liquid of the present invention is formed from the above-mentioned resin, thus improving the flexural strength and providing sufficient strength to withstand airflow pressure. In this case, the flexural strength of the cured product, measured using a three-point bending stress gauge, is preferably 3 MPa or more, and more preferably 5 MPa or more.

[0229] -Removal liquid-

[0230] The remover contains organic solvents and, depending on the requirements, other components. To distinguish between the organic solvents in the styling liquid and those in the remover, the organic solvents in the styling liquid can be referred to as the first organic solvent, and the organic solvents in the remover as the second organic solvent.

[0231] Examples of organic solvents include ketones, halogens, alcohols, esters, ethers, hydrocarbons, glycols, glycol ethers, glycol esters, pyrrolidones, amides, amines, and carbonates.

[0232] Examples of ketones include acetone, methyl ethyl ketone, diethyl ketone, methyl propyl ketone, methyl isobutyl ketone, methyl pentyl ketone, cyclohexanone, isophorone, acetophenone, and diacetone alcohol.

[0233] Examples of halogens include dichloromethane, trichloroethylene, perchloroethylene, HCFC141-b, HCFC-225, 1-bromopropane, chloroform, and o-dichlorobenzene.

[0234] Examples of alcohols include methanol, ethanol, butanol, isobutanol, isopropanol, n-propanol, tert-butanol, sec-butanol, 1,3-butanediol, 1,4-butanediol, 2-ethylhexanol, benzyl alcohol, etc.

[0235] Examples of esters include methyl acetate, ethyl acetate, butyl acetate, isobutyl acetate, sec-butyl acetate, methoxybutyl acetate, 3-methoxybutyl acetate, 3-methoxy-3-methylbutyl acetate, ethyl 3-ethoxypropionate, pentyl acetate, n-propyl acetate, isopropyl acetate, methyl lactate, ethyl lactate, butyl lactate, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether propionate, ethyl 3-ethoxypropionate, and dimethyl dimethacrylate (DBE).

[0236] Examples of ethers include dimethyl ether, ethyl methyl ether, diethyl ether, ethylene oxide, tetrahydrofuran, furan, benzofuran, diisopropyl ether, methyl cellosolve, ethyl cellosolve, butyl cellosolve, 1,4-dioxane, methyl tert-butyl ether (MTBE), ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol diethyl ether, triethylene glycol dimethyl ether, diethylene glycol dibutyl ether, dipropylene glycol dimethyl ether, dipropylene glycol monomethyl ether, etc.

[0237] Examples of hydrocarbons include benzene, toluene, xylene, solvent naphtha, n-hexane, isohexane, cyclohexane, ethylcyclohexane, methylcyclohexane, cyclohexene, cycloheptane, cyclopentane, heptane, pentomethyl, pentane, methylcyclopentane, n-heptane, isooctane, n-decane, n-pentane, isopentane, mineral oil, dimethyl sulfoxide, and linear alkylbenzenes.

[0238] Examples of diols include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, and dimethoxytetraethylene glycol.

[0239] Examples of glycol esters include ethylene glycol monoethyl ether acetate and diethylene glycol monobutyl ether acetate.

[0240] Examples of glycol ethers include methyl carbitol, ethyl carbitol, butyl carbitol, and methyl triethylene glycol.

[0241] Examples of pyrrolidones include 2-pyrrolidone, N-ethyl-2-pyrrolidone, and N-methyl-2-pyrrolidone.

[0242] Examples of amides include dimethylformamide, dimethylacetamide, and formamide.

[0243] Examples of amines include tetramethylethylenediamine, N,N-diisopropylethylamine, ethylenediamine, triethylamine, diethylamine, aniline, pyrrolidine, piperidine, morpholine, pyrrole, pyridine, pyridazine, oxazole, thiazole, and 1,3-dimethyl-2-imidazolinone.

[0244] Examples of carbonates include diethyl carbonate, dimethyl carbonate, propylene carbonate, and methyl ethyl carbonate.

[0245] Other components that can be included in the removal solution include, for example, surfactants, defoamers, preservatives and mildew inhibitors, pH adjusters, chelating agents, and rust inhibitors.

[0246] <Drying Process>

[0247] The drying process is a process of drying the green blank to remove liquid components such as removal liquid remaining in the green blank, and is carried out by a drying device.

[0248] The drying process can remove not only liquid components such as cleaning solutions contained in the green body, but also organic matter.

[0249] There are no particular restrictions on the type of drying device; it can be selected appropriately according to the purpose. Examples include well-known dryers and constant temperature and humidity baths.

[0250] <Degreasing process>

[0251] The degreasing process is a process of heating the green body to form a degreased body to remove resin, which is carried out by a degreasing device.

[0252] The term "degreased body" refers to a three-dimensional object obtained by degreasing the organic components of the aforementioned resins from a green body.

[0253] The degreasing process uses a degreasing device, which heats the green blank to a temperature above the thermal decomposition temperature of the organic components of the aforementioned resins, etc., but below the melting point or solidus temperature of the material (metal) constituting the metal particles (e.g., using AlSi). 10 When Mg particles are used, the green body is heated at approximately 570°C for a certain period of time (e.g., 1 to 10 hours) to decompose and remove organic components.

[0254] There are no particular restrictions on degreasing devices; they can be selected appropriately according to the purpose. Examples include well-known sintering furnaces and electric furnaces.

[0255] <Sintering Process>

[0256] The sintering process is a process of heating the degreased body formed in the degreasing process to form a sintered body, and it is carried out by a sintering device.

[0257] The so-called "sintered body" is a three-dimensional object formed by integrating metal materials that constitute inorganic particles into a single metal material, which is formed by sintering and debinding.

[0258] The sintering process uses a sintering apparatus to heat the degreased body to the solidus temperature of the metallic material that constitutes the inorganic particles (e.g., using AlSi). 10 When using Mg particles, the temperature is above 570°C and the liquidus temperature (e.g., using AlSi) is also above that of Mg particles. 10 When Mg particles are heated at a temperature below approximately 600°C for a certain period of time (e.g., 1 to 10 hours), the metal materials constituting the metal particles are integrated.

[0259] There are no particular restrictions on the sintering apparatus; it can be selected appropriately according to the purpose. Examples include well-known sintering furnaces. The sintering apparatus can be the same as the degreasing apparatus mentioned above. Furthermore, the degreasing process and the sintering process can be carried out continuously.

[0260] Post-processing steps

[0261] The manufacturing method of the shaped object preferably includes a post-processing step that treats the sintered body. There are no particular restrictions on the post-processing step, and it can be appropriately selected according to the purpose. Examples include surface protection treatment and coating.

[0262] The surface protection treatment process is a process of forming a protective layer on a three-dimensional molded object (green body) formed in the curing process. By performing this surface protection treatment process, the surface of the cured object can be given durability, such as allowing it to be used directly. Specific examples of protective layers include waterproof layers, weather-resistant layers, light-resistant layers, heat-insulating layers, and gloss layers.

[0263] Examples of surface protection treatment devices include, for instance, well-known surface protection treatment devices such as spraying devices and coating devices.

[0264] The coating process is the process of applying paint to the three-dimensional model (green body) formed by the curing process, which consists of layers of cured material. Through the coating process, the green body can be dyed the desired color.

[0265] As a coating apparatus, examples include known coating apparatuses, such as coating apparatuses that use sprayers, rollers, brushes, etc.

[0266] <The process of styling>

[0267] Here, refer to Figures 3A to 3E The shaping process in the manufacturing method of the shaped object of the present invention is explained. Figures 3A-3E This is a schematic diagram illustrating an example of the movement of a modeling device.

[0268] The object-making apparatus includes a supply tank 21, a molding tank 22, and a residual powder receiving tank 29. The supply tank 21 and the molding tank 22 each have a supply platform 23 and a molding platform 24 that can move up and down. Powder 20 for three-dimensional modeling is placed on the molding platform 24 provided in the molding tank 22, and a powder layer 31 is formed from the powder 20.

[0269] First, the state of the first layer of molding liquid being applied to the molding platform 24 of the molding tank 22 will be explained. When the subsequent powder layer containing inorganic particles is formed on the first layer of molding liquid applied to the layer 30, such as... Figure 3A As shown, the supply platform 23 of the supply tank 21 rises, causing the molding platform 24 of the molding tank 22 to fall. At this time, the falling distance of the molding platform 24 is set so that the distance (layer spacing) between the upper surface of the powder layer in the molding tank 22 and the lower part (lower tangential portion) of the planarization roller 12 is Δt1. The spacing Δt1 is not particularly limited, but is preferably around tens of μm to 100 μm.

[0270] The leveling roller 12 is configured to create a gap relative to the upper surfaces of the supply trough 21 and the molding trough 22. Therefore, when powder 20 containing inorganic particles is fed into the molding trough 22 for leveling, the upper surface of the powder layer containing inorganic particles becomes higher than the upper surfaces of the supply trough 21 and the molding trough 22. This reliably prevents the leveling roller 12 from contacting the upper surfaces of the supply trough 21 and the molding trough 22, reducing damage to the leveling roller 12. If the surface of the leveling roller 12 is damaged, the powder layer 31 supplied to the molding trough 22 (see...) will be affected. Figure 3D Stripes are generated on the surface of the flattening roller, which easily reduces flatness. The flattening roller 12 is provided with a powder removal plate 13 as a powder removal component, which is used to contact the peripheral surface of the flattening roller 12 to remove the powder 20 adhering to the flattening roller 12.

[0271] Secondly, such as Figure 3B As shown, by rotating the flattening roller 12 in the direction of the arrow, the powder 20 containing inorganic particles, positioned above the upper end surface of the supply trough 21, is moved toward the molding trough 22, thereby conveying and supplying the powder 20 containing inorganic particles to the molding trough 22 (powder supply). Furthermore, as... Figure 3C As shown, the planarization roller 12 moves parallel to the surface of the molding platform 24 of the molding groove 22, forming a powder layer 31 (planarization) of a predetermined thickness Δt1 on the molding groove 22 of the molding platform 24. At this time, the powder 20 containing the remaining inorganic particles not used to form the powder layer 31 falls into the remaining powder receiving tank 29. After the powder layer 31 is formed, as... Figure 3D As shown, the flattening roller 12 moves to the side of the supply trough 21 and returns (restores) to the initial position (origin position).

[0272] Here, the planarizing roller 12 is movable while maintaining a constant distance from the upper surfaces of the molding groove 22 and the supply groove 21. By maintaining a constant distance and being movable, the planarizing roller 12 transports the powder 20 onto the molding groove 22. Simultaneously, a powder layer 31 of uniform thickness h (corresponding to the interlayer spacing Δt1) can be formed on the molding groove 22 or on the already formed molding liquid-applied layer 30. In the following text, the thickness h of the powder layer 31 and the interlayer spacing Δt1 are sometimes not distinguished; unless otherwise specified, they have the same thickness and the same meaning. Furthermore, the thickness h of the powder layer 31 can be obtained through actual measurement; in this case, the average value from multiple locations is preferably used.

[0273] After that, as Figure 3EAs shown, droplets 10 of the molding liquid are ejected from the nozzle 52 of the liquid ejection unit, and a molding liquid-applied layer 30 of the desired shape is formed on the next powder layer 31. Then, the powder layer formation process and the molding liquid application process are repeated to form a new molding liquid-applied layer 30. At this point, the new molding liquid-applied layer 30 and the layer below it are integrated. Thereafter, the powder layer formation process and the molding liquid application process are repeated further to complete the laminate.

[0274] Here, Figure 4 This is the front view of the device that represents the overall structure of the apparatus for manufacturing three-dimensional objects.

[0275] (Viewed from the side). The three-dimensional model manufacturing apparatus 100 includes a recoat roller 103 for planarizing powder layers, a residue receiver 105 for receiving excess material, and a modeling plate 106 for stacking powder layers. The recoat roller 103 can rotate in a direction different from the direction of movement of the powder supply device 104 and the recoat roller 103 (the rotation direction of the recoat roller). Figure 4 In this structure, the nozzle surface condition detection device 107 is an optical camera with a light source 108, disposed outside the molding groove 101. Furthermore, one of the purposes of this nozzle surface condition detection device 107 is to detect liquid and ejected medium 102 that are blocking the nozzle. Therefore, when using an optical camera, the image needs to be magnified to a certain extent for observation, which narrows the field of view, making it impossible to capture the entire nozzle head 110 (all nozzles) at once. Therefore, the nozzle head 110 is scanned by an optical camera, and the entire nozzle is observed using multiple images. However, it is also possible to use multiple optical cameras to capture images without scanning the nozzle head 110. Furthermore, to observe the nozzle surface, a laser displacement meter or similar device can be used instead of an optical camera to capture the shape in three dimensions. Additionally, the light source associated with the optical camera can be a light source with a wavelength capable of distinguishing between the nozzle surface and the ejected medium, or it can be set at an angle. Furthermore, to capture the ejected medium adhering to the nozzle surface in three dimensions using an optical camera, a method of illuminating multiple widths of striped light can also be employed.

[0276] Figure 5 This diagram illustrates the conditions under which the ejected medium 102 can adhere to the nozzle surface 116 due to the ejection of the modeling liquid droplets 111.

[0277] Reference Figure 5 This explains the conditions under which the sprayed medium 102 can adhere to the nozzle surface 116 due to the ejection of the modeling liquid droplets 111. Figure 4 different, Figure 5This shows the state of the spray medium 102 ejected from the nozzle 110 onto the styling tank. Furthermore, in order to illustrate the condition that the spray medium 102 can adhere to the nozzle surface 116 due to the ejection of styling liquid droplets 111, the droplets 111 ejected from the nozzle 110 are shown in enlarged form.

[0278] To ensure that the modeling fluid droplets 111 land accurately on the spray medium 102, the spray velocity of the modeling fluid droplets needs to be above a certain level. This is because the actual velocity vector of the modeling fluid droplets 111 is the spray velocity (Vj) plus the carriage movement velocity (Vc), causing the droplets 111 to fly out at an angle. Therefore, due to the velocity fluctuations of the carriage 109 and the deviation of the spray gap (Dt) between the nozzle surface 116 and the spray medium, the landing point of the modeling fluid droplets 111 has an error. The effect of this deviation (error) of Vc and Dt on the landing point position is that the faster (larger) Vj is, the smaller the deviation (error) of Vc and Dt. Moreover, the larger Vj is, the shorter the time to reach the landing point, and the smaller the influence of the airflow (generated by the movement of the carriage, etc.) on the landing point position. For the same reason, the spray gap (Dt) needs to be maintained below a certain level.

[0279] Furthermore, to improve the productivity (speed) of stacked three-dimensional objects, the size (Mj) of the modeling fluid droplets 111 needs to be large enough. Also, the larger Mj is, the less influence the airflow (generated by the movement of the carriage, etc.) has on the landing point. In addition, to improve the resolution (surface quality, precision) of the modeled object, the size (particle size) of the powder needs to be small enough.

[0280] Under these conditions, powder tends to adhere to the nozzle surface 116, leading to poor spraying of the molding liquid and reduced reliability. In this case, the nozzle surface 116 needs to be cleaned. However, if maintenance is performed by wiping the powder-coated nozzle surface 116 with a scraper, the powder will enter the nozzle and clog it. Therefore, cleaning and maintenance can be achieved by washing the nozzle surface 116 with a cleaning solution to remove the adhered powder, thus cleaning the nozzle surface 116 without allowing powder to enter the nozzle.

[0281] Figure 6 and Figure 7 This illustrates an example of cleaning and maintenance.

[0282] Figure 6 This is a diagram illustrating an embodiment in which the nozzle surface is immersed in the cleaning fluid.

[0283] As an example of cleaning nozzle face 116 Figure 6 This indicates that the nozzle face 116 is immersed in a cleaning tank 113 filled with cleaning fluid 112 to remove dirt.

[0284] exist Figure 6In the middle, the cleaning tank 113 filled with cleaning fluid rises toward the nozzle surface 116, so that the nozzle surface 116 is immersed in the cleaning fluid 112.

[0285] This embodiment is just an example; it could also be that the nozzle face 116 descends into the cleaning tank 113.

[0286] By storing the cleaning fluid 112 in the cleaning tank 113, a large amount of cleaning fluid is used, and the cleaning fluid needs to be replaced regularly.

[0287] To improve the cleaning effect of the cleaning tank 113, a device that applies external force such as ultrasonic waves can be provided.

[0288] After rinsing, you can use a wiping tool to clean the area afterward in order to allow the styling liquid to form a meniscus.

[0289] Figure 7 This diagram illustrates the implementation of cleaning the nozzle surface via a cleaning fluid spraying mechanism.

[0290] As an example of cleaning nozzle face 116 Figure 7 This indicates that cleaning fluid 112 is sprayed onto nozzle surface 116 to remove dirt.

[0291] exist Figure 7 In the process, cleaning fluid 112 is sprayed out by using the cleaning fluid spraying mechanism 114 provided on the platform 115 to clean the nozzle surface 116.

[0292] In order to ensure that the cleaning fluid 112 is applied to the entire nozzle surface 116, the moving stage 115 applies the cleaning fluid 112.

[0293] This implementation is just one example; it could also be a cleaning fluid spraying mechanism that covers the entire nozzle surface.

[0294] The cleaning fluid spraying mechanism 114 can be a hydraulic head or a pump.

[0295] After cleaning, you can use a wiping tool to clean the area afterward in order to allow the styling liquid to form a meniscus.

[0296] Because the nozzle surface 116 is waterproofed, the cleaning fluid 112 easily forms droplets.

Example

[0297] Embodiments of the present invention will be described below, but the present invention is not limited to these embodiments.

[0298] (Examples 1-19 and Comparative Examples 1-6)

[0299] <Preparation of the modeling liquid>

[0300] The materials in Tables 1 to 5 were mixed and stirred with a magnetic stirrer for 2 hours while being heated to 80°C. After stirring for 2 hours, the heating was stopped and the mixture was stirred continuously until it reached room temperature (25°C) to prepare the modeling liquids of Examples 1 to 19 and Comparative Examples 1 to 6.

[0301] The numerical values ​​for the content of each material in Tables 1-5 are in mass %. Here, each content represents the total amount, not the solid content.

[0302] Next, the physical properties of each of the obtained modeling liquids were measured as follows. The results are shown in Tables 1-5.

[0303] <Viscosity η of the modeling liquid>

[0304] The viscosity η of each molding liquid at 25°C was measured using a cone-plate viscometer VISCOMETER TV-25 manufactured by Toki Sangyo Co., Ltd. at 25°C.

[0305] <Surface tension γ of the modeling liquid>

[0306] The surface tension γ of each modeling liquid at 23°C was measured at 23°C using an automatic surface tension meter DY-300 manufactured by Kyowa Interface Science Co., Ltd., by the Wilhelmy method (suspension plate method).

[0307] <Contact Angle θn (Plane Method)>

[0308] The contact angle θn between each molding liquid and the metal plate was measured at 25°C using a contact angle meter DMs-301 manufactured by Kyowa Interface Science Co., Ltd.

[0309] As the metal plate, aluminum-free plate A 6061 LNQ-25-10-5 manufactured by Misumi Corporation was used. The syringe was filled with molding fluid, and an approximately 2.0 μL droplet was dropped onto the metal plate using the automatic droplet forming function. After 20 seconds, the droplet shape was obtained using the θ / 2 method, and this value was taken as the contact angle θn (plate method).

[0310] <Powder contact angle θ>

[0311] The contact angle θ between the molding liquid and the inorganic particles was measured using an automatic surface tension meter DY-500 manufactured by Kyowa Interface Science Co., Ltd.

[0312] As a powder containing inorganic particles, aluminum powder (ALSI3-30B manufactured by Toyo Aluminum Co., Ltd.) is used.

[0313] The column was filled with 5g of powder containing inorganic particles, and the porosity was adjusted to 35.6% to 35.8% using a powder compressor.

[0314] Using acetone as a liquid with sufficient wettability for powders containing inorganic particles, and assuming the powder contact angle θ of acetone is 0 degrees, the capillary radius is calculated. The "capillary radius" refers to the radius of the gap between inorganic particles when metal particles are packed into the column, and is measured using an automatic surface tension meter DY-500 manufactured by Kyowa Interface Science Co., Ltd.

[0315] Next, using an automatic surface tension meter DY-500 manufactured by Kyowa Interface Science Co., Ltd., the penetration rate of the molding liquid into the powder containing inorganic particles was measured within a range of 150 to 180 seconds from the start of the measurement. The penetration rate of the molding liquid into the powder containing inorganic particles was expressed by the Lucas-Washburn formula of the following equation (1).

[0316]

[0317] Here, in equation (1), l(t) wetted denoted as t, where t is the measurement time, r is the average capillary radius, γ is the surface tension of the molding liquid at 23℃, θ is the contact angle between the molding liquid and the inorganic particles, and η is the viscosity of the molding liquid at 25℃.

[0318] Based on the obtained capillary radius, permeation velocity, viscosity γ of the molding liquid at 25°C, and surface tension η of the molding liquid at 23°C, the powder contact angle θ between the molding liquid and the inorganic particles is calculated according to the above formula (1). The molding liquid is used to measure 3 times, and the minimum value is taken as the powder contact angle θ.

[0319] <γcosθ / η>

[0320] Calculate γcosθ / η (m / s) as an indicator of penetration rate. θ is the contact angle (°) between the molding liquid and the inorganic particles, γ is the surface tension (mN / m) of the molding liquid at 23℃, and η is the viscosity (mPa·s) of the molding liquid at 25℃.

[0321] <Methods of Manufacturing Shaped Objects>

[0322] As each molding liquid and inorganic particle, aluminum powder (manufactured by Toyo Aluminum Co., Ltd., ALSI3-30B) is used to layer and mold the various shapes as follows to obtain each shaped object.

[0323] (1) First, use as follows Figures 3A-3E The apparatus for manufacturing the shaped object shown conveys aluminum powder from the supply tank 21 to the molding tank 22, forming a thin layer of aluminum powder with an average thickness of 84 μm on the molding table 24.

[0324] (2) Next, in the molding apparatus, each type of molding liquid is applied to the surface of the formed aluminum powder thin layer through the nozzle of an inkjet printhead (RICOH MH5421 industrial inkjet manufactured by Ricoh Corporation). The amount of molding liquid is 140 picoliters per layer at a resolution of 300 dpi. The molding liquid is sprayed out in rectangles of 54 mm × 10 mm and 28 mm × 10 mm.

[0325] (3) Next, repeat the operations of (1) and (2) above until the total average thickness of the 54mm×10mm rectangle is 2mm and the total average thickness of the 28mm×10mm rectangle is 3mm, and form a laminate by sequentially stacking thin layers of aluminum powder (lamination process).

[0326] (4) Next, the laminate is heated and dried under vacuum to obtain a cured product (heating process).

[0327] (5) Next, the remaining powder is removed from the solidified material by airflow (removal of remaining powder process).

[0328] Through the above processes, a 54mm×10mm rectangular object was used for dimensional accuracy evaluation, and a 28mm×10mm cuboid object was used for bending strength evaluation.

[0329] <Evaluation of Dimensional Accuracy>

[0330] The dimensions of each 54mm × 10mm rectangular object were measured with calipers, and the dimensional accuracy was evaluated according to the following evaluation criteria.

[0331] Evaluation Criteria

[0332] ◎: The error between the dimensions and the design data is less than 0.5mm, and the outline is clear.

[0333] ○: The error between the dimensions and the design data is less than 0.5mm, but the outline is slightly blurred. This occurs in the process of removing residual powder, which is an exudate that can be easily removed (because it can be removed, it is marked as ○ here).

[0334] ×: The error between the actual dimensions and the dimensions is greater than 0.5mm, or it occurs in the process of removing residual powder and exudates that are not easily removed.

[0335] <Evaluation of Bending Strength>

[0336] The bending strength of each 28mm × 10mm rectangle was determined using the Autograph AG-I universal testing machine manufactured by Shimadzu Corporation. Specifically, using a 1kN load cell and a 3-point bending fixture with a support point spacing of 24mm, the stress versus strain was plotted for each shape as it was displaced at a rate of 1mm / min. The stress at the fracture point was defined as the bending strength (MPa), and the evaluation was performed according to the following evaluation criteria.

[0337] Evaluation Criteria

[0338] ◎: Bending strength above 5MPa

[0339] ○: Bending strength is above 3MPa and less than 5MPa

[0340] ×: Bending strength less than 3MPa

[0341] <Evaluation of Ejaculatory Performance>

[0342] The nozzles of the inkjet printheads (RICOH MH5421 industrial printheads manufactured by Ricoh Corporation) in the modeling apparatus using each type of modeling liquid ejected for 3 seconds under ejection conditions of 2kHz and 24kHz, paused for 10 seconds, and repeated 100 times. The number of missing nozzles per 100 nozzles was counted, and the ejection performance was evaluated according to the following evaluation criteria.

[0343] Evaluation Criteria

[0344] ◎: When ejecting at 2kHz and 24kHz, there are two or fewer missing nozzles.

[0345] When the output is 0.2kHz, the number of missing nozzles is less than 2; when the output is 24kHz, the number of missing nozzles is greater than 2.

[0346] ×: When ejecting at 2kHz and 24kHz, the number of missing nozzles is greater than 2.

[0347] Table 1

[0348]

[0349] Table 2

[0350]

[0351] Table 3

[0352]

[0353] Table 4

[0354]

[0355] Table 5

[0356]

[0357] The details of the various materials in Tables 1 to 5 are as follows.

[0358] -Resin-

[0359] • Resin A: JMR-10LL, a partially saponified polyvinyl acetate resin manufactured by Vinyl Acetate & Poval Co., Ltd. of Japan.

[0360] • Resin B: S-Lec BL-10, polyvinyl butyral resin manufactured by Sekisui Chemicals Co., Ltd.

[0361] -Organic solvents-

[0362] • Triglyme: Triethylene glycol dimethyl ether manufactured by Sankyo Chemical Co., Ltd.

[0363] •DESU: Diethyl succinate manufactured by Tokyo Chemical Industry Co., Ltd.

[0364] •TG / Tac: A mixture of triglyme manufactured by Sankyo Chemical Co., Ltd. and triglyceride manufactured by Tokyo Chemical Industry Co., Ltd. in a mass ratio of 60:40.

[0365] -surfactant-

[0366] Surflon S-693, manufactured by AGC Seichemical Co., Ltd., is a fluorinated surfactant.

[0367] • BYK333, manufactured by BYK-Chemie Japan Co., Ltd., is a silicone surfactant.

[0368] • BYK378, manufactured by BYK-Chemie Japan Co., Ltd., is a silicone surfactant.

[0369] •S-611, manufactured by AGC Seichemical Co., Ltd., Surflon S-611 is a fluorinated surfactant.

[0370] Surflon S-647, manufactured by AGC Seichemical Co., Ltd., is a fluorinated surfactant.

[0371] • SAG020, manufactured by Nissin Chemical Industries, Ltd., is an organosilicon surfactant.

[0372] KF353, manufactured by Shin-Etsu Chemical Co., Ltd., is a fluorinated surfactant.

[0373] In Table 1, the molding liquid was prepared by changing the resin content in Examples 1-5 and Comparative Example 1.

[0374] It was found that when the resin content decreased, the viscosity of the molding liquid at 25°C decreased, the penetration rate increased ("γcos θ / η" increased), and the bending strength of the molded object decreased.

[0375] Furthermore, dimensional accuracy is good when “γcosθ / η” is below 1.5, and even better when “γcos θ / η” is below 1.

[0376] Furthermore, when the viscosity of the molding liquid at 25°C is above 6 mPa·s, the bending strength of the molded object is good, and when the viscosity of the molding liquid at 25°C is above 12 mPa·s, the bending strength of the molded object is even better.

[0377] In Table 2, the modeling liquid was prepared by changing the content of surfactant in Comparative Example 2 and Examples 6-11.

[0378] It was found that when the molding liquid does not contain surfactants, the contact angle θ of the powder decreases, and the dimensional accuracy of the molded object deteriorates.

[0379] When the molding liquid contains surfactants, the powder contact angle θ increases. The higher the surfactant content, the greater the tendency for the powder contact angle θ to increase. When the powder contact angle θ is above 50°, the dimensional accuracy of the molded object is good. When "γcos θ / η" is below 1.0, the dimensional accuracy is even better.

[0380] Furthermore, it was found that the styling liquid exhibited excellent sprayability when the surface tension of the styling liquid was above 22 mN / m at 23°C.

[0381] In Tables 3 and 5, modeling liquids were prepared by changing the type of surfactant in Comparative Examples 3-6 and Examples 15-19.

[0382] The surfactants in Comparative Examples 3 to 6 (“BYK333”, “BYK378”, “S-611”, “S-647”) all had powder contact angles θ less than 50°, indicating poor dimensional accuracy.

[0383] The surfactants (“SAG020” and “KF353”) in Examples 15-19 all exhibit good dimensional accuracy, flexural strength and sprayability.

[0384] In Table 4, modeling liquids were prepared by changing the type of organic solvent in Examples 12 and 13. The organic solvents (“DESU” and “TG / TAc”) used in Examples 12 and 13 all yielded good results in terms of dimensional accuracy, flexural strength, and ejection performance.

[0385] Additionally, in Example 14 of Table 4, the type of resin was changed to prepare the molding liquid. The resin (resin B) of Example 14 was found to have good dimensional accuracy, flexural strength, and sprayability.

[0386] <Amount of Styling Liquid>

[0387] In Example 2, the amount of modeling liquid applied was adjusted by adjusting the volume, resolution, or number of droplets applied to each voxel of modeling liquid in each nozzle, just as in Examples 1-19 and Comparative Examples 1-6. As shown in Table 6 below, a 30mm × 10mm × 3mm cuboid model was manufactured.

[0388] Next, for the obtained shapes No. 1 to 14, the following evaluations were conducted: presence of localized seepage was assessed, flexural strength was measured, and a comprehensive evaluation was performed. The results are shown in Table 6 and... Figure 2 middle.

[0389] <Evaluation of the presence or absence of localized exudation>

[0390] Visually inspect each 30mm × 10mm × 3mm cuboid shape for areas known as localized leakage, and evaluate them according to the following criteria. Localized leakage is characterized by, for example, being larger than expected and occurring on the side. This is because when the powder is conveyed onto the molding tank by the leveling rollers, the molding liquid is applied in a layer under pressure, causing it to spread across the powder surface. The impact when removing powder around the shape can easily remove localized leakage, resulting in a problem with the product.

[0391] Evaluation Criteria

[0392] ○: No localized exudation

[0393] ×: Localized oozing

[0394] <Bending Strength>

[0395] The bending strength of each 30mm × 10mm × 3mm cuboid was measured using the Autograph AG-I general-purpose testing machine manufactured by Shimadzu Corporation. Specifically, a 1kN load cell and a 3-point bending fixture with a support point spacing of 24mm were used. The load points were displaced at a rate of 1mm / min. The stress versus strain of each object during displacement was plotted. The stress at the fracture point was defined as the bending strength (MPa), and the evaluation was performed according to the following evaluation criteria.

[0396] Evaluation Criteria

[0397] ○: Bending strength is above 3MPa

[0398] △: Bending strength ≥ 0.5MPa ≤ 3MPa

[0399] ×: Bending strength less than 0.5 MPa

[0400] <Overall Evaluation>

[0401] Based on the evaluation results of localized seepage and flexural strength, a comprehensive evaluation is conducted according to the following criteria.

[0402] Evaluation Criteria

[0403] ○: Both localized seepage and flexural strength are evaluated using ○.

[0404] △: One of the evaluation criteria for localized effusion or flexural strength is △

[0405] ×: One of the evaluation criteria for localized exudation or flexural strength is ×, or both are ×.

[0406] Table 6

[0407]

[0408] From Table 6 and Figure 2 The results showed that the amount of modeling liquid applied was 0.033 μl / mm. 3 Above and 0.33 μl / mm 3 The following Figure 2 Within range A, when the powder is conveyed to the molding tank by the planarizing roller, even when the molding liquid is pushed, there is sufficient space on both sides of each droplet for the liquid to wet and spread, and the molding liquid does not seep out locally. Furthermore, it was found that when the amount of molding liquid applied is 0.033 μl / mm... 3 At this point, the sculpture collapses.

[0409] Furthermore, the amount of modeling liquid applied was 0.148 μl / mm. 3 Above and 0.33 μl / mm 3 The following Figure 2 Within range B, the amount of resin supporting the sculpture increases, and the flexural strength of the sculpture is above 3 MPa. When the flexural strength of the sculpture is above 3 MPa, a 30 mm × 10 mm × 3 mm cuboid sculpture has the strength to not break even if dropped from a height of 100 mm.

[0410] <Evaluation of Cleaning and Maintenance>

[0411] Regarding cleaning and maintenance, during the application of cleaning fluid to the nozzle surface, the cleaning fluid is drawn from the nozzle, and the modeling fluid within the nozzle may mix with the cleaning fluid. This mixing of modeling fluid and cleaning fluid is referred to as color mixing. During cleaning and maintenance, the following steps are taken: Figure 9 The nozzle face cleaning fluid ejection mechanism shown uses triethylene glycol dimethyl ether as the cleaning fluid.

[0412] After spraying the molding liquid of Example 2 onto a transparent sheet (OHP sheet VF-1420N, manufactured by KOKUYO Corporation), aluminum powder (ALSI3-30B, manufactured by Toyo Aluminum Co., Ltd.) was sprinkled on the sprayed area to make it visible, forming a shape as shown in the image. Figures 8A-8C The pattern shown is created by the aluminum powder adhering to the area where the molding liquid falls, thus forming the pattern.

[0413] like Figure 8A As shown, the ejection line is clearly visible during normal operation, while... Figure 8B and 8C As shown, the spray line is blurred after cleaning and maintenance. This means the landing point of the molding fluid deviates from the target position, or the molding fluid droplets are broken into multiple droplets instead of a single droplet. The reason is believed to be that the molding fluid in the nozzle mixes with the cleaning fluid during cleaning and maintenance, altering the properties of the molding fluid and making the spray unstable. If the properties of the molding fluid change or the spray is unstable, the quality of the sculpted object, such as its strength and dimensional accuracy, will be adversely affected.

[0414] Therefore, by controlling the pressure applied to the nozzle during cleaning and maintenance (hereinafter referred to as "control pressure"), it is possible to prevent the molding fluid and cleaning fluid in the nozzle from mixing.

[0415] Typically, in order to eject modeling liquid from the nozzle, an appropriate negative pressure needs to be applied and maintained within the nozzle. Typically, the applied negative pressure is approximately -25 mmol / L to -10 mmol / L. In this invention, the pressure of the modeling liquid applied to the nozzle is controlled (control pressure).

[0416] Secondly, use a cleaning solution (triethylene glycol dimethyl ether) and such as Figure 9 The nozzle surface cleaning fluid spraying mechanism shown enables the moving stage to move at a speed of 10 mm / s. Figure 7 Cleaning and maintenance were performed under the condition of changing the control pressure. Afterwards, the molding liquid of Example 2 was sprayed onto a transparent sheet (OHP sheet VF-1420N, manufactured by KOKUYO Corporation), and then aluminum powder (manufactured by Toyo Aluminum Co., Ltd., ALSI3-30B) was sprinkled on it. Figures 8A-8C The printed pattern is shown, and the blurring degree (color mixing) of the ejected lines is determined according to the following criteria. The results are shown in Table 7.

[0417] Evaluation Criteria

[0418] like Figure 8B As shown, if the sprayed lines are blurry (color mixing state: △), such as Figure 8C As shown, if the spray lines are quite blurry (mixed color state: ×), such as Figure 8A As shown, the ejected lines are not blurred (no color mixing: ○).

[0419] Table 7

[0420] Controlling pressure -25mmaq -10mmaq 0mmaq 10mmaq 25mmaq 50mmaq 100mmaq Blurred ejection lines × × ○ ○ ○ ○ ○

[0421] As shown in Table 7, color mixing occurs when cleaning and maintenance are performed while maintaining a normal control pressure of -25 mmol / L to -10 mmol / L, but does not occur when the control pressure is set to 0 mmol / L or higher. That is, by setting the pressure of the modeling fluid applied to the nozzle to a positive pressure during cleaning and maintenance, the cleaning fluid is not drawn into the nozzle, thus preventing color mixing. Furthermore, it was found that even when no modeling fluid droplets flow from the nozzle, color mixing does not occur when the control pressure is between 0 mmol / L and 25 mmol / L.

[0422] When the control pressure exceeds 25 mmol / L, modeling fluid droplets flow out of the nozzle (in purging mode), leaving droplets on the nozzle surface after cleaning and maintenance. Therefore, it is necessary to remove the residual modeling fluid droplets by wiping or other methods. If the modeling fluid is prone to solidification, it may remain on the nozzle surface during wiping and maintenance, potentially solidifying.

[0423] On the other hand, when the control pressure is between 0 mmol / L and 25 mmol / L, the molding fluid is not purged, so only cleaning fluid remains on the nozzle surface after cleaning and maintenance. Therefore, compared to when the control pressure is set to more than 25 mmol / L, the likelihood of molding fluid solidifying on the nozzle surface is lower. Alternatively, as described later, depending on the cleaning and maintenance conditions, it is possible to prevent cleaning fluid from remaining on the nozzle surface. In this case, wiping maintenance is unnecessary, and the degradation of the hydrophobic film on the nozzle surface caused by wiping maintenance can be prevented.

[0424] Evaluation of powder removal performance, cleaning solution residue, and color mixing.

[0425] The nozzle surface with powder adhering to it is cleaned and maintained. The condition of the nozzle surface before and after cleaning and maintenance is photographed. The powder removal efficiency, cleaning solution residue, and color mixing degree are evaluated by comparing the images. Cleaning and maintenance are performed using... Figure 9 The nozzle surface cleaning fluid ejection mechanism shown in Table 8 was evaluated by changing the moving speed of the cleaning fluid ejection mechanism and controlling the pressure to -25 mmol / L and +25 mmol / L. Cleaning and maintenance were performed using cleaning fluid (triethylene glycol dimethyl ether), the molding fluid from Example 2, and aluminum powder (manufactured by Toyo Aluminum Co., Ltd., ALSI3-30B). After cleaning and maintenance, the molding fluid from Example 2 was sprayed onto a transparent sheet (0HP sheet VF-1420N, manufactured by KOKUYO Co., Ltd.), and then aluminum powder (ALSI3-30B, manufactured by Toyo Aluminum Co., Ltd.) was sprinkled on top. Figures 8A-8C The degree of blurring (color mixing) of the ejected lines in the printed pattern shown is determined according to the following criteria.

[0426] The results are shown in Table 8. Figure 10A It is a photograph showing the state of the nozzle surface after cleaning. Figure 10B It is a photograph showing the state of powder adhering to the nozzle surface. Figure 10C This is a photograph showing the state of the nozzle surface after cleaning and maintenance at a moving speed of 10 mm / s. Figure 10D This is a photograph showing the state of the nozzle surface after cleaning and maintenance at a moving speed of 30 mm / s. Figure 10E This is a photograph showing the state of the nozzle surface after cleaning and maintenance at a moving speed of 50 mm / s.

[0427] Evaluation Criteria

[0428] (i) Regarding powder removal performance, a rating of ○ is given when more than 90% of the powder adhering to the nozzle surface is removed, and a rating of × is given when less than 90% is removed.

[0429] (ii) Regarding residual cleaning fluid, if there is no cleaning fluid residue on the nozzle surface after cleaning and maintenance, it is rated as ○; if there is a small amount of residue, it is rated as △; and if there is a lot of residual cleaning fluid, it is rated as ×.

[0430] (iii) During cleaning and maintenance, the same procedures apply as usual, maintaining the pressure at -25 mLaq. Subsequently, the results of color mixing are assessed as follows: Figures 8B-8C As shown. If color mixing occurs as follows: Figure 8B The evaluation is Δ if color mixing occurs, as shown below. Figure 8C The result shown is rated as ×, if no color mixing occurs. Figure 8A The result shown is rated as O.

[0431] (iv) During cleaning and maintenance, adjust the control pressure to +25 mmAq and perform color mixing determination in the same way as in (iii).

[0432] Table 8

[0433]

[0434] As can be seen from the results in Table 8, in order to remove the powder adhering to the nozzle surface, the moving speed must be below 20 mm / s.

[0435] Regarding color mixing, the slower the moving speed, the longer the contact time between the cleaning fluid and the nozzle surface, increasing the risk of color mixing. In fact, when performing cleaning and maintenance at a control pressure of -25 mm / s, the degree of color mixing tends to worsen as the moving speed decreases. On the other hand, it has been confirmed that cleaning and maintenance at a control pressure of +25 mm / s can suppress color mixing. However, even at a control pressure of +25 mm / s, some color mixing still occurs at a moving speed of 5 mm / s.

[0436] Therefore, during cleaning and maintenance, in order to remove powder adhering to the nozzle surface and prevent color mixing, the preferred moving speed of the cleaning fluid spraying mechanism is 10 mm / s to 20 mm / s. In this experiment, the contact distance between the cleaning fluid and the nozzle surface is 20 mm (refer to...). Figure 9 This means that each point on the nozzle surface should be given cleaning fluid for 1 to 2 seconds.

[0437] Furthermore, after cleaning and maintenance, the presence of any residual styling fluid or cleaning fluid droplets on the nozzle surface was evaluated. The results showed no droplet residue below 10 mm / s. If droplets were present on the nozzle surface, they would have to be removed by wiping or similar methods. However, this is unnecessary when the moving speed is set to 10 mm / s. Eliminating the need for wiping reduces the time required for wiping and prevents degradation of the hydrophobic film caused by wiping.

[0438] In addition, even if there is still color mixing at a moving speed of 5mm / s, the color mixing can be eliminated by spraying out the styling liquid after cleaning and maintenance (the spray line will not be blurred).

[0439] Examples of the present invention are shown below.

[0440] <1> A molding liquid for imparting a powder layer containing inorganic particles, characterized in that:

[0441] The contact angle θ between the powder and the inorganic particles is greater than 50°, and satisfies the following formula: γ cos θ / η ≤ 1.5 (m / s).

[0442] In the above formula, θ represents the powder contact angle (°) between the molding liquid and the inorganic particles, γ represents the surface tension (mN / m) of the molding liquid at 23°C, and η represents the viscosity (mPa·s) of the molding liquid at 25°C.

[0443] <2> A molding liquid for imparting a powder layer containing inorganic particles, characterized in that:

[0444] The contact angle θ between the powder and aluminum particles is greater than 50°, and satisfies the following formula: γ cos θ / η≤1.5(m / s).

[0445] In the above formula, θ represents the powder contact angle (°) between the molding liquid and the aluminum particles, γ represents the surface tension (mN / m) of the molding liquid at 23°C, and η represents the viscosity (mPa·s) of the molding liquid at 25°C.

[0446] <3> As mentioned above <1> ~ <2> The styling liquid according to any one of the following methods is characterized in that the contact angle θ of the powder is 50° or more and 80° or less.

[0447] <4> As mentioned above <1> ~ <3> The modeling liquid in any one of the following methods is characterized by satisfying the following formula: γ cos θ / η≤1(m / s).

[0448] <5> As mentioned above <1> ~ <4> The styling liquid described in any one of the following examples is characterized in that its viscosity η at 25°C is 6 mPa·s or higher.

[0449] <6> As mentioned above <1> ~ <5> The styling liquid described in any one of the following examples is characterized in that its viscosity η at 25°C is 12 mPa·s or higher.

[0450] <7> As mentioned above <1> ~ <6> The styling liquid described in any one of the following examples is characterized in that its surface tension γ at 23°C is 22 mN / m or higher.

[0451] <8> As mentioned above <1> ~ <7> The styling liquid in any one of the following methods is characterized in that the amount of styling liquid applied is 0.033 μl / mm. 3 Above and 0.33 μl / mm 3 the following.

[0452] <9> As mentioned above <8> The styling liquid is characterized by having an applied volume of 0.148 μl / mm. 3 Above and 0.33 μl / mm 3 the following.

[0453] <10> As mentioned above <1> ~ <9> The styling liquid described in any one of the following examples is characterized by having a resolution of 600 dpi or higher.

[0454] <11> As mentioned above <1> ~ <10> The styling liquid in any one of the following methods is characterized in that, when a cleaning liquid is applied to the nozzle surface of the nozzle from which the styling liquid is sprayed, the pressure applied to the nozzle is controlled to be 0 mmol / L or more and 25 mmol / L or less.

[0455] <12> like <11> The styling liquid is characterized in that the time for applying the cleaning liquid to the nozzle surface is more than 1 second and less than 2 seconds.

[0456] <13> A molding liquid for imparting a powder layer containing inorganic particles, characterized in that it contains a resin having a structural unit represented by the following structural formula (1), an organic solvent, and a surfactant.

[0457]

Chemical Formula 1

[0458]

[0459] <14> As mentioned above <13> The molding liquid is characterized in that the surfactant is at least one of a fluorinated surfactant and an organosilicon surfactant.

[0460] <15> like <13> ~ <14> The styling liquid according to any one of the following methods is characterized in that the content of the surfactant is 0.001% by mass or more and 1% by mass or less.

[0461] <16> As mentioned above <13> ~ <15> The molding liquid of any one of the above is characterized in that the resin having the structural unit represented by the structural formula (1) comprises at least one selected from polyvinyl acetate resin, partially saponified polyvinyl acetate resin and polyvinyl butyral resin.

[0462] <17> As mentioned above <13> ~ <16> The styling liquid according to any one of the following methods is characterized in that the content of the resin having the structural unit represented by the structural formula (1) is 5% by mass or more and 20% by mass or less.

[0463] <18> like <13> ~ <17> The modeling liquid according to any one of the following methods is characterized in that the organic solvent has at least one structure selected from alkoxy, ether, and ester bonds.

[0464] <19> like <18> The molding liquid is characterized in that the organic solvent comprises an alkylene glycol dialkyl ether compound.

[0465] <20> like <13> ~ <19> The styling liquid described in any one of the following examples is characterized in that it is substantially water-free.

[0466] <21> like <13> ~ <20> The molding liquid described in any one of the following examples is characterized in that the powder contact angle θ with the inorganic particles is 50° or more, and satisfies the following formula:

[0467] γ cos θ / η≤1.5(m / s),

[0468] In the above formula, θ represents the powder contact angle (°) between the molding liquid and the inorganic particles, γ represents the surface tension (mN / m) of the molding liquid at 23°C, and η represents the viscosity (mPa·s) of the molding liquid at 25°C.

[0469] <22> A styling kit, characterized in that it includes the components described above. <1> ~ <21> The molding liquid as described in any one of the following, and the inorganic particles.

[0470] <23> like <22> The aforementioned styling kit is characterized in that the inorganic particles are metal particles, and the metal particles contain at least one selected from aluminum, zinc, magnesium, and their alloys.

[0471] <24> like <20> ~ <21> The styling kit described in any one of the following examples is characterized in that the surface of the inorganic particles is not coated with resin.

[0472] <25> A method for manufacturing a shaped object, characterized by comprising:

[0473] The powder layer forming process forms a powder layer containing inorganic particles;

[0474] The molding liquid application process involves applying the molding liquid as described in any one of claims 1 to 19 to the powder layer; and

[0475] The layering process involves repeating the powder layer formation process and the molding liquid application process in sequence to form a layered material.

[0476] <26> like <25> The method for manufacturing the shaped object is characterized in that the shaping liquid application process sprays the shaping liquid onto the powder layer in an inkjet manner.

[0477] <27> As mentioned above <25> ~ <26> The method for manufacturing the model described in any one of the above methods is characterized by further comprising:

[0478] The heating process involves heating the laminated material to form a solidified product; and

[0479] The process of removing residual powder involves removing the powder adhering to the solidified material, i.e., the residual powder, to obtain a green body.

[0480] <28> As mentioned above <27> The method for manufacturing the aforementioned shaped object is characterized by further comprising:

[0481] The degreasing process involves heating the green body to form a degreased body from which resin has been removed; and

[0482] In the sintering process, the degreased body is heated to form a sintered body.

[0483] According to the above <1> ~ <21> The styling liquid mentioned in any one of the above <22> ~ <24> The styling kit mentioned in any one of the above, and the above <25> ~ <28> The manufacturing method of the shaped object described in any one of the inventions can solve many previous problems and achieve the purpose of the invention.

Claims

1. A molding liquid to be applied to a powder layer containing inorganic particles, characterized by: a powder contact angle θ of 50° or more with a powder of the inorganic particles, and satisfying the following formula: γcosθ / η ≤ 1.5 m / s, in the above formula, θ represents a powder contact angle of the molding liquid with the powder of the inorganic particles, in °, γ represents a surface tension of the molding liquid at 23°C, in mN / m, and η represents a viscosity of the molding liquid at 25°C, in mPa-s, and the powder contact angle θ is a value calculated from a penetration speed in a range of 150 seconds to 180 seconds from the start of measurement when the molding liquid penetrates into a column filled with a powder containing inorganic particles.

2. The molding liquid according to claim 1, characterized in that: the inorganic particles are aluminum particles. the powder contact angle θ is 50° or more and 80° or less. satisfies the following formula: γcosθ / η ≤ 1 m / s.

3. The molding fluid according to any one of claims 1 to 2, wherein the viscosity η at 25°C is 6 mPa-s or more.

4. The molding fluid according to any one of claims 1 to 3, wherein the resolution is 600 dpi or more.

5. The molding fluid according to any one of claims 1 to 4, wherein when a cleaning liquid is applied to a nozzle surface provided to a nozzle for ejecting the molding liquid, the pressure applied to the nozzle is controlled to be 0 mmaq or more and 25 mmaq or less.

6. The molding fluid according to any one of claims 1 to 5, wherein The amount of molding liquid applied was 0.033 μl / mm. 3 Above and 0.33 μl / mm 3 the following.

7. The styling fluid of claim 6 wherein, The amount of styling fluid imparted was 0.148 μl / mm 3 The above and 0.33 μl / mm 3 The above.

8. The molding fluid according to any one of claims 1 to 7, wherein the time for which the cleaning liquid is applied to the nozzle surface is 1 second or more and 2 seconds or less.

9. The molding fluid according to any one of claims 1 to 8, wherein contains a resin having a structural unit represented by the following structural formula (1), an organic solvent, and a surfactant 10. The styling fluid of claim 9 wherein, the surfactant is at least one of a fluorine-containing surfactant and a silicone surfactant.

11. The styling fluid of claim 1 wherein, the content of the surfactant is 0.001 mass% or more and 1 mass% or less. 。 12. The modeling fluid of claim 11 wherein, the resin having the structural unit represented by the structural formula (1) contains at least one selected from the group consisting of a polyvinyl acetate resin, a partially saponified polyvinyl acetate resin, and a polyvinyl butyral resin.

13. The molding fluid according to any one of claims 11 to 12, wherein the content of the resin having the structural unit represented by the structural formula (1) is 5 mass% or more and 20 mass% or less.

14. A molding fluid according to any one of claims 11 to 13, wherein the organic solvent has at least one structure selected from the group consisting of an alkoxy group, an ether bond, and an ester bond.

15. The molding fluid according to any one of claims 11 to 14, wherein the organic solvent contains an alkylene glycol dialkyl ether compound.

16. The molding fluid according to any one of claims 11 to 15, wherein substantially does not contain water.

17. The modeling fluid of claim 16 wherein, includes the molding liquid according to any one of claims 1 to 18, and inorganic particles.

18. The molding fluid according to any one of claims 11 to 17, wherein the inorganic particles are metal particles containing at least one selected from the group consisting of aluminum, zinc, magnesium, and alloys thereof.

19. A styling kit, characterized by the surface of the inorganic particles is not covered with a resin.

20. The molding kit of claim 19, wherein, includes:

21. A modeling kit according to any one of claims 19-20, characterized in that a powder layer forming step of forming a powder layer containing inorganic particles; 22. A method of manufacturing a molded article, characterized by, a molding liquid applying step of applying the molding liquid according to any one of claims 1 to 18 to the powder layer; and a laminating step of sequentially repeating the powder layer forming step and the molding liquid applying step to form a laminate. the molding liquid applying step ejects the molding liquid to the powder layer in an inkjet manner. further includes:

23. The method for producing a shaped article according to Claim 22, wherein a heating step of forming a cured product by heating the laminate; 24. The method for producing a shaped article according to any one of claims 22 to 23, wherein and a remaining powder removing step of removing the powder, i.e., a remaining powder, adhering to the cured product to obtain a green body. further includes: a debinding step of forming a debound product in which a resin is removed by heating the green body; 25. The method for manufacturing a molded article according to Claim 24, wherein and a sintering step of forming a sintered product by heating the debound product. ​ ​

Images