Manufacturing method of three-dimensional object and modeling liquid for manufacturing three-dimensional object

Abstract

To provide a manufacturing method of a three-dimensional object which can improve the sintering density of three-dimensional object.SOLUTION: A manufacturing method of a three-dimensional objects includes: a powder layer forming process of forming a powder layer containing powder with metal particles; and a modeling liquid applying process of applying, to the power layer, modeling liquid containing at least one high acid value compound with an acid value of 120 mgKOH / g or more, selected from a group consisting of rosin compounds, styrene compounds, and acrylic compounds, and an organic solvent.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a method for producing a three-dimensional object and a modeling liquid for producing a three-dimensional object. [Background technology]

[0002] In recent years, there has been an increasing need to produce complex, fine objects made of metals, etc. One technology that meets this need is to create objects using powder containing metal particles by binder jetting (hereinafter sometimes referred to as "BJ"), and then sinter them using powder metallurgy.

[0003] As a technique for sintering powder containing metal particles, Patent Document 1 discloses, for example, a conductive ink capable of firing a conductive film pattern having sufficient conductivity and good adhesion to a substrate at a low temperature. This conductive ink contains silver nanoparticles, a dispersion medium, and a terpene resin or rosin having a softening point of 90°C or higher that is attached to the surface of the silver nanoparticles or is contained in the dispersion medium, and a short-chain amine having a carbon number of 5 or less is attached to at least a part of the surface of the silver nanoparticles. This conductive ink contains metal particles in the conductive ink, and the terpene resin or rosin is used as an adhesive that does not inhibit sintering. Therefore, rosin remains in the conductive film after sintering, and the sintering density cannot be improved. Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide a method for manufacturing a three-dimensional object, which is capable of improving the sintered density of the three-dimensional object. [Means for solving the problem]

[0005] The manufacturing method of a three-dimensional object of the present invention as a means for solving the above-mentioned problems is characterized by comprising a powder layer formation step of forming a powder layer containing a powder including metal particles, and a modeling liquid application step of applying to the powder layer a modeling liquid containing an organic solvent and a high acid value compound having an acid value of 120 mgKOH / g or more and being at least one selected from the group consisting of rosin compounds, styrene compounds, and acrylic compounds. Effect of the Invention

[0006] According to the present invention, it is possible to provide a method for manufacturing a three-dimensional object capable of improving the sintered density of the three-dimensional object. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic diagram of a modeling apparatus 100 according to one embodiment of the present invention. [Figure 2A] FIG. 2A is a schematic diagram showing an example of the operation of the modeling apparatus 100 according to an embodiment of the present invention. [Figure 2B] FIG. 2B is a schematic diagram showing another example of the operation of the modeling apparatus 100 according to an embodiment of the present invention. [Figure 2C] FIG. 2C is a schematic diagram showing another example of the operation of the modeling apparatus 100 according to an embodiment of the present invention. [Figure 2D] FIG. 2D is a schematic diagram showing another example of the operation of the modeling apparatus 100 according to an embodiment of the present invention. [Figure 2E] FIG. 2E is a schematic diagram showing another example of the operation of the modeling apparatus 100 according to an embodiment of the present invention. [Diagram 3] FIG. 3 is a schematic diagram showing a system for forming a three-dimensional object according to one embodiment of the present invention. [Figure 4] FIG. 4 is a flowchart showing a method for manufacturing a three-dimensional object according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, the embodiments of the present invention will be described in detail. Note that the embodiments are not limited to the following description, and may be modified within the scope of what a person skilled in the art can imagine, such as other embodiments, additions, modifications, or deletions, and any aspect is within the scope of the present invention as long as it provides the functions and effects of the present invention.

[0009] In the present invention, unless otherwise specified, the use of "to" indicating a numerical range means that the numerical values ​​before and after it are included as the lower limit and upper limit.

[0010] (Method of manufacturing three-dimensional objects) The method for producing a three-dimensional object of the present invention includes a powder layer formation step of forming a powder layer containing a powder including metal particles, and a modeling liquid application step of applying to the powder layer a modeling liquid containing an organic solvent and at least one high acid value compound selected from the group consisting of rosin compounds, styrene compounds, and acrylic compounds, having an acid value of 120 mgKOH / g or more, and preferably further includes a heating step, a degreasing step, and a sintering step, and further includes other steps such as an excess powder removal step, as necessary.

[0011] A wide variety of metals, including aluminum alloys, are being considered as powders containing metal particles for use in the BJ method. Among these, solvent-based inks are being considered as inks suitable for the BJ method with aluminum alloys, from the perspective of handling aluminum powder. However, it is known that some aluminum alloys have difficulty being densified by sintering, depending on their composition. For example, valve metals such as magnesium, titanium, zinc, and tantalum react easily with oxygen and tend to form an oxide film on the metal surface, resulting in a very high melting point, which becomes an obstacle when sintering the metal. Therefore, inks more suitable for aluminum alloys are needed.

[0012] Among valve metals, aluminum alloys having a particularly high magnesium content have been found to be more difficult to densify by sintering than aluminum alloys containing no magnesium or less magnesium.

[0013] The method for producing a three-dimensional object of the present invention uses a modeling liquid containing an organic solvent and at least one high acid value compound selected from the group consisting of rosin compounds, styrene compounds, and acrylic compounds, having an acid value of 120 mgKOH / g or more, thereby making it possible to reduce or remove the oxide film on the surface of metal particles, which has been a problem in the past, and thereby improving the sintered density of the three-dimensional object. In particular, even when metal particles that are prone to forming an oxide film on their surfaces are used, the method for producing a three-dimensional object of the present invention can suitably reduce or remove the oxide film on the surface of the metal particles, thereby improving the sintered density of the three-dimensional object.

[0014] Here, the following definitions are used for terms used in the present invention. In the present invention, a "shaped object" refers to an object that is formed through a powder layer forming process in which a powder layer containing powder including metal particles is formed, and a modeling liquid application process in which a modeling liquid is applied to the powder layer, or by repeating the powder layer forming process and the modeling liquid application process. In the present invention, the term "solidified product" refers to a product (three-dimensional product) that maintains a certain three-dimensional shape after a heating process in which a shaped product is heated. The term "solidified product" also refers to a product that has not undergone an excess powder removal process in which excess powder that does not constitute a three-dimensional product is removed. In the present invention, the term "precursor of a three-dimensional object" refers to an object that has been subjected to an excess powder removing step in which excess powder is removed. The term "precursor of a three-dimensional object" refers to an object that maintains a certain three-dimensional shape and preferably has substantially no excess powder attached thereto. In the present invention, the term "three-dimensional modeling" refers to the process up to the production of a three-dimensional object precursor before the degreasing process. In the present invention, the term "degreased body" refers to a material obtained by a degreasing step in which organic matter is removed from a solidified material or a precursor of a three-dimensional object. In the present invention, the term "sintered body" refers to a body formed by integrating the metal material that constitutes the metal particles, and is obtained by a sintering process in which a degreased body is sintered. In the present invention, the term "three-dimensional object" refers mainly to an object obtained after all steps have been completed. Therefore, when the manufacturing method of a three-dimensional object includes other steps such as a degreasing step and a sintering step, the term refers to an object obtained after the completion of the other steps. In other words, when the manufacturing method of a three-dimensional object includes a post-treatment step, the "three-dimensional object" is a sintered body that has been post-treated.

[0015] <Powder layer formation process> The powder layer forming step is a step of forming a powder layer containing powder including metal particles (hereinafter, may be abbreviated as "powder"). The powder layer is preferably formed on a modeling stage. The method of forming the powder layer by disposing the powder on the modeling stage is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include a method using a known counter rotation mechanism (counter roller) or the like, a method using a member such as a brush, roller, or blade, a method of pressing the surface of the powder with a pressing member, and a method using a known layered modeling device.

[0016] When a powder layer is formed using a powder layer forming means such as a counter rotation mechanism (counter roller), brush, roller, blade, or pressing member, the method can be carried out as follows, for example. That is, powder is placed on a modeling stage arranged so as to be able to move up and down while sliding on the inner wall of an outer frame (sometimes called a "mold," "hollow cylinder," "cylindrical structure," etc.) using a counter rotation mechanism (counter roller), brush, roller, blade, or pressing member. At this time, when a modeling stage that can move up and down within the outer frame is used as the modeling stage, the modeling stage is placed slightly below the upper end opening of the outer frame, that is, it is positioned below by the thickness of the powder layer, and the powder is placed on the modeling stage. In this manner, a powder layer of powder can be placed on the modeling stage.

[0017] The thickness of the powder layer is not particularly limited and can be appropriately selected depending on the purpose, but the average thickness per layer is preferably 30 μm to 500 μm, more preferably 60 μm to 300 μm. When the average thickness of the powder layer is 30 μm or more, the strength of the molded object formed by applying the molding liquid to the powder is improved, and deformation that may occur in subsequent steps such as the sintering step can be suppressed. In addition, when the average thickness of the powder layer is 500 μm or less, the dimensional accuracy of the molded object formed by applying the molding liquid to the powder is improved.

[0018] In the present invention, the "average thickness" of the powder layer means the average value of thicknesses at three points arbitrarily selected from the powder layer.

[0019] <<Powder containing metal particles>> The powder containing metal particles contains metal particles and further contains other components as required. The powder containing metal particles is a powder that contains a plurality of metal particles, and a molded object is manufactured by applying a molding liquid to a powder layer that contains the powder.

[0020] The repose angle of the powder containing metal particles is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 60° or less, more preferably 50° or less, and even more preferably 40° or less. When the repose angle of the powder containing metal particles is 60° or less, the powder containing metal particles can be efficiently and stably placed at a desired location on the modeling stage. The angle of repose of a powder containing metal particles can be measured, for example, using a powder property measuring device (Powder Tester PT-N type, manufactured by Hosokawa Micron Corporation).

[0021] -Metal particles- The metal particles contain at least one selected from the group consisting of particles made of pure metal and particles made of alloy. The metal particles are particles containing metal as a constituent material of the shaped object. The metal particles are not particularly limited as long as they contain metal, and may be particles made of pure metal, particles made of alloy, or may contain materials other than metal, but it is preferable that the main material is metal. The powder containing metal particles may be a powder containing metal particles of pure metal and metal particles of alloy.

[0022] When the main material is a metal, it means that the mass of the metal contained in the metal particle is 50.0 mass% or more, preferably 60.0 mass% or more, more preferably 70.0 mass% or more, even more preferably 80.0 mass% or more, and particularly preferably 90.0 mass% or more, relative to the mass of the metal particle.

[0023] Examples of metals that are constituent materials of metal particles include aluminum (Al), magnesium (Mg), silicon (Si), 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), and alloys of these metals. Among these, stainless steel (SUS), iron (Fe), copper (Cu), silver (Ag), titanium (Ti), aluminum (Al), magnesium (Mg), silicon (Si), and alloys of these metals are preferably used, and aluminum (Al), magnesium (Mg), silicon (Si), and alloys of these metals are more preferably used.

[0024] Alloys containing magnesium (Mg) have low density and high specific strength, and are widely used for electronic device housings and automobile-related parts that value light weight, but have a problem of being prone to forming oxide films. In contrast, the method for producing a three-dimensional object of the present invention can preferably thin or remove the oxide films on the surfaces of metal particles, even if the metal particles are alloys containing magnesium (Mg), by using the modeling liquid of the present invention. This can improve the sintering density of the three-dimensional object.

[0025] When liquid phase sintering is performed to sinter the degreased body, silicon (Si) breaks through the oxide film of the metal particles and comes out. This allows silicon (Si) to fill the gaps between the metal particles, and allows the sintering of the metal particles to proceed smoothly.

[0026] Examples of aluminum alloys include AlSi10Mg, AlSi12, AlSi7Mg0.6, AlSi3Mg, AlSi1Mg, AlSi9Cu3, Toyal Scalmalloy (registered trademark) (AlMg4.5Sc0.7Zr0.3, manufactured by Toyo Aluminum K.K.), ADC12, AlSi3, etc. These may be used alone or in combination of two or more.

[0027] Metal particles can be manufactured using a conventionally known method. There is no particular limitation on the method for manufacturing metal particles, and examples thereof include a pulverization method in which a solid metal is subjected to compression, impact, friction, etc. to be broken down into small pieces, an atomization method in which a molten metal is sprayed to obtain a quenched powder, a precipitation method in which a component derived from a metal dissolved in a liquid is precipitated, and a gas phase reaction method in which a metal compound is vaporized and crystallized. Among these, the atomization method is preferred as a method for manufacturing metal particles, since it can obtain a spherical shape and has little variation in particle size. Examples of the atomization method include a water atomization method, a gas atomization method, a centrifugal atomization method, and a plasma atomization method, and all of them are preferably used.

[0028] The metal particles may be commercially available products. Examples of commercially available products include AlSi10Mg (manufactured by Toyo Aluminum Co., Ltd., Si10MgBB), AlSi1Mg (manufactured by Toyo Aluminum Co., Ltd., Si1MgBB), pure Al (manufactured by Toyo Aluminum Co., Ltd., A1070-30BB), pure Ti (manufactured by Osaka Titanium Technologies Co., Ltd.), SUS316L (manufactured by Sanyo Special Steel Co., Ltd., product name: PSS316L), SiO2 (manufactured by Tokuyama Corporation, product name: Excelica SE-15K), AlO2 (manufactured by Taimei Chemical Industry Co., Ltd., product name: Taimicron TM-5D), and ZrO2 (manufactured by Tosoh Corporation, product name: TZ-B53).

[0029] The volume average particle diameter of the metal particles is not particularly limited and can be appropriately selected according to the purpose, but is preferably 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 diameter of the metal particles is 2 μm or more, the aggregation of the metal particles is suppressed, and the decrease in the production efficiency of the three-dimensional object and the decrease in the handleability of the metal particles can be suppressed. In addition, when the volume average particle diameter of the metal particles is 100 μm or less, the decrease in the contact points between the metal particles and the increase in voids can be suppressed, and the decrease in the strength of the three-dimensional object can be suppressed.

[0030] The particle size distribution of the metal particles is not particularly limited and can be appropriately selected depending on the purpose, but a sharper particle size distribution is preferable.

[0031] The volume average particle size and particle size distribution of the metal particles can be measured using a known particle size measuring device, for example, a particle size distribution measuring device (Microtrac MT3000II series, manufactured by Microtrac Bell).

[0032] -Other ingredients- Other components contained in the powder containing metal particles are not particularly limited as long as they do not impair the effects of the present invention and can be appropriately selected depending on the purpose, and examples thereof include fillers, leveling agents, sintering aids, polymer resin particles, etc. These may be used alone or in combination of two or more.

[0033] --Filler-- Fillers are effective materials for adhering to the surfaces of metal particles and for filling the gaps between metal particles. By using fillers, for example, the flowability of the powder can be improved, and the number of contact points between metal particles can be increased, thereby reducing the gaps, thereby improving the strength and dimensional accuracy of the three-dimensional object.

[0034] --Leveling agent-- The leveling agent is a material that is effective for controlling the wettability of the surface of the powder layer. By using the leveling agent, for example, the permeability of the modeling liquid into the powder layer can be increased, and the strength of the three-dimensional object can be increased.

[0035] --Sintering aid-- The sintering aid is an effective material for increasing the sintering efficiency when sintering the degreased body. By using the sintering aid, for example, the strength of the three-dimensional object can be improved, the sintering temperature can be lowered, and the sintering time can be shortened.

[0036] --Polymer resin particles-- Polymer resin particles are effective materials for adhering to the surfaces of metal particles, and are also called organic external additives. The average particle size of the polymer resin particles is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 0.1 μm to 10.0 μm, more preferably 0.1 μm to 1.0 μm.

[0037] <Modeling liquid application process> The modeling liquid application step is a step of applying a modeling liquid to the powder layer, the modeling liquid containing an organic solvent and at least one high acid value compound selected from the group consisting of rosin compounds, styrene compounds, and acrylic compounds, each having an acid value of 120 mgKOH / g or more. A modeled object can be obtained by going through the powder layer formation step and the modeling liquid application step, or by repeating the powder layer formation step and the modeling liquid application step.

[0038] The method of applying the modeling liquid to the powder layer is preferably a method of ejecting the modeling liquid. The method of ejecting the modeling liquid is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include a dispenser method, a spray method, and an inkjet method.

[0039] <<Modeling liquid>> The molding liquid contains a high acid value compound having an acid value of 120 mgKOH / g or more, which is at least one selected from the group consisting of rosin compounds, styrene compounds, and acrylic compounds, and an organic solvent. The molding liquid may further contain other components such as resins other than the high acid value compound, additives, etc.

[0040] The viscosity of the modeling liquid is not particularly limited and can be appropriately selected depending on the purpose, but is preferably from 5 mPa·s to 50 mPa·s, more preferably from 5 mPa·s to 40 mPa·s, and even more preferably from 5 mPa·s to 30 mPa·s at 25° C. When the viscosity of the modeling liquid is from 5 mPa·s to 50 mPa·s at 25° C., the ejection from the modeling liquid application means such as an inkjet head is stabilized, and the accurate ejection of the modeling liquid further improves the bending strength of the modeled object, solidified object, three-dimensional model precursor, and the like in a pre-sintered state, and further improves the dimensional accuracy. The viscosity of the molding liquid can be measured, for example, in accordance with JIS K 7117-2:1999.

[0041] The surface tension of the modeling liquid is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 40 mN / m or less, more preferably 10 mN / m to 40 mN / m, and even more preferably 10 mN / m to 30 mN / m at 25° C. When the surface tension of the modeling liquid is 40 mN / m or less, the ejection from the modeling liquid application means such as an inkjet head is stabilized, and the accurate ejection of the modeling liquid further improves the bending strength of the modeled object, solidified object, and three-dimensional model precursor in a pre-sintered state, and also improves the dimensional accuracy. The surface tension of the modeling liquid can be measured, for example, by an automatic surface tensiometer (DY-300, manufactured by Kyowa Interface Science Co., Ltd.).

[0042] -High acid value compounds- The high acid value compound is at least one compound selected from the group consisting of rosin compounds, styrene compounds, and acrylic compounds, each having an acid value of 120 mgKOH / g or more. The inclusion of the high acid value compound in the modeling liquid has the advantage that the oxide film on the metal particles can be suitably thinned or removed, and the compound is ultimately decomposed, leaving no residue.

[0043] [Acid value] The acid value of the high acid value compound is not particularly limited as long as it is 120 mgKOH / g or more, but the upper limit is preferably 350 mgKOH / g or less, and more preferably 300 mgKOH / g or less.

[0044] The acid value of the high acid value compound may be a catalog value or may be calculated by measurement. The acid value of the high acid value compound can be measured, for example, according to JIS K 0070:1992 or JIS K 2501:2003.

[0045] [Glass transition temperature (Tg)] The glass transition temperature (Tg) of the high acid value compound is not particularly limited and can be appropriately selected depending on the purpose, but the lower limit is preferably not less than 45° C., more preferably not less than 50° C., and even more preferably not less than 60° C. If the glass transition temperature (Tg) of the modeling liquid is 60° C. or higher, it is preferable in that the desired shape can be maintained without softening the modeled object, solidified object, and pre-sintered objects such as a three-dimensional modeled object precursor at ambient temperature.

[0046] The glass transition temperature (Tg) of the high acid value compound can be measured, for example, using a differential scanning calorimeter (DSC) (for example, DSC2500, manufactured by TA Instruments Japan, Inc.) Specifically, the glass transition temperature (Tg) of the high acid value compound can be measured by the following procedure. First, 1 g of the modeling liquid is weighed into an aluminum cup and heated on a hot stirrer at 150°C for 6 hours to obtain a dried product. A portion of the dried product is scraped off from the aluminum cup to be used as the target sample. The target sample is placed in an alumina sample container, which is then placed on a holder unit and set in an electric furnace. Next, the sample is heated to 200°C (first time) in the range of -30°C to 200°C, cooled to -30°C (second time), heated to 200°C (third time), and cooled to -30°C (fourth time). The data from the third heating is used as the glass transition temperature (Tg) of the high acid value compound.

[0047] -Rosin compounds with an acid value of 120 mgKOH / g or more- The rosin compound having an acid value of 120 mgKOH / g or more is not particularly limited and can be appropriately selected depending on the purpose, but is preferably at least one selected from the group consisting of acid-modified rosin, polymerized rosin, hydrogenated rosin, rosin-modified maleic acid resin, formylated rosin, fumarated rosin, rosin-modified alkyd resin, and acrylated rosin resin, and more preferably acid-modified rosin or polymerized rosin.

[0048] The molecular weight of the rosin compound having an acid value of 120 mgKOH / g or more is not particularly limited, but the number average molecular weight (Mn) is preferably 300 or more and 100,000 or less, and more preferably 600 or more and 30,000 or less.

[0049] The method for measuring the number average molecular weight (Mn) of a rosin compound having an acid value of 120 mgKOH / g or more is not particularly limited and can be appropriately selected depending on the purpose. For example, it can be measured by gel permeation chromatography.

[0050] The rosin compound having an acid value of 120 mgKOH / g or more may be a commercially available product or may be appropriately synthesized. Examples of commercially available rosin compounds with an acid value of 120 mgKOH / g or more include Pine Crystal KR-120 (acid-modified ultra-light-colored rosin) and Pine Crystal KE-604. (acid-modified ultra-light-colored rosin), Pine Crystal KR-140 (ultra-light-colored polymerized rosin) (both manufactured by Arakawa Chemical Industries, Ltd.), Tespol 1150 (rosin-modified maleic acid resin), Tespol 1158 (rosin-modified maleic acid resin) (both manufactured by Harima Chemical Group, Inc.).

[0051] The method for synthesizing a rosin compound having an acid value of 120 mgKOH / g or more is not particularly limited, and can be appropriately selected from among known methods.

[0052] -Styrene compounds with an acid value of 120 mgKOH / g or more- The styrene compound having an acid value of 120 mgKOH / g or more is not particularly limited and can be appropriately selected depending on the purpose, but is preferably at least one selected from the group consisting of styrene-acrylic resins and styrene-maleic acid resins.

[0053] The molecular weight of the styrene compound having an acid value of 120 mgKOH / g or more is not particularly limited, but the number average molecular weight (Mn) is preferably 300 or more and 100,000 or less, and more preferably 600 or more and 30,000 or less. The number average molecular weight (Mn) of a styrene compound having an acid value of 120 mgKOH / g or more can be measured in the same manner as for a rosin compound.

[0054] The styrene compound having an acid value of 120 mgKOH / g or more may be a commercially available product or may be appropriately synthesized. Commercially available styrene compounds having an acid value of 120 mgKOH / g or more include, for example, HS-2190 (styrene acrylic resin) (manufactured by Seiko PMC Corporation) and X-200 (styrene maleic acid resin) (manufactured by Seiko PMC Corporation).

[0055] The method for synthesizing a styrene compound having an acid value of 120 mgKOH / g or more is not particularly limited, and can be appropriately selected from among known methods.

[0056] -Acrylic compounds with an acid value of 120 mgKOH / g or more- The acrylic compound having a value of 120 mgKOH / g or more is not particularly limited and can be appropriately selected depending on the purpose, but is preferably an acrylic resin.

[0057] The molecular weight of the acrylic compound having an acid value of 120 mgKOH / g or more is not particularly limited, but the number average molecular weight (Mn) is preferably 300 or more and 100,000 or less, and more preferably 600 or more and 30,000 or less. The number average molecular weight (Mn) of an acrylic compound having an acid value of 120 mgKOH / g or more can be measured in the same manner as for a rosin compound.

[0058] The acrylic compound having an acid value of 120 mgKOH / g or more may be a commercially available product or may be appropriately synthesized. An example of a commercially available acrylic compound having an acid value of 120 mgKOH / g or more is RS-1190 (acrylic resin) (manufactured by Seiko PMC Corporation).

[0059] The method for synthesizing an acrylic compound having an acid value of 120 mgKOH / g or more is not particularly limited, and can be appropriately selected from among known methods.

[0060] The presence of the high acid value compound in the three-dimensional object precursor can be confirmed by analysis using gas chromatography mass spectrometry or the like.

[0061] The content of the high acid value compound is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 1% by mass or more and 20% by mass or less, and more preferably 3% by mass or more and 15% by mass or less. When the content of the high acid value compound is 1% by mass or more, the oxide film of the metal particles can be preferably thinned or removed, and the sintered density can be easily improved, and when it is 30% by mass or less, good inkjet ejection can be maintained.

[0062] -Resins other than high acid value compounds- Resins other than the high acid value compound can function as a binder. Resins other than high acid value compounds are preferably thermally decomposed to 95% by mass or more, and more preferably 97% by mass or more, when heated from 30° C. to 550° C. "The resin is thermally decomposed" means that random decomposition of the main chain or depolymerization at the molecular chain end occurs, and the resin is removed by vaporization, oxidative decomposition, combustion, etc.

[0063] Thermal decomposition is measured by TG-DTA (thermogravimetry and differential thermal analysis). Specifically, the temperature is raised from 30°C to 550°C at a rate of 10°C / min in air or nitrogen atmosphere, and after reaching 550°C, the temperature is held for 2 hours, and the weight loss rate before and after the temperature rise is calculated.

[0064] The glass transition temperature (Tg) of the resin other than the high acid value compound is preferably 45° C. or higher, more preferably 50° C. or higher, and even more preferably 60° C. or higher. The glass transition temperature (Tg) of a resin other than a high acid value compound can be measured in the same manner as the glass transition temperature (Tg) of a molding liquid, except that a resin other than a high acid value compound is used as the target sample.

[0065] The softening point of the resin other than the high acid value compound is preferably 70° C. or higher, more preferably 80° C. or higher, and even more preferably 90° C. or higher. The softening point of the resin other than the high acid value compound is preferably 150° C. or lower, more preferably 140° C. or lower, and even more preferably 130° C. or lower.

[0066] The softening point of resins other than high acid value compounds can be measured using a micro melting point apparatus (e.g., MP-S3, manufactured by Yanaco Instrument Development Laboratory Co., Ltd.) Specifically, the softening point is measured by raising the temperature of the target sample at a rate of 2°C / min and observing the state of the target sample.

[0067] The number average molecular weight (Mn) of the resin other than the high acid value compound is preferably 5,000 or more and 50,000 or less, and more preferably 10,000 or more and 30,000 or less.

[0068] The method for measuring the number average molecular weight (Mn) of the resin other than the high acid value compound is not particularly limited and can be appropriately selected depending on the purpose. For example, it can be measured by gel permeation chromatography.

[0069] The resin other than the high acid value compound is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include a resin having at least one structural unit selected from the group consisting of a structural unit represented by the following structural formula (1) and a structural unit represented by the following structural formula (2). Note that the "structural unit" refers to a partial structure in the resin derived from one or more polymerizable compounds. [ka] [ka]

[0070] For example, resins other than the high acid value compound include polyvinyl acetate resin, partially saponified polyvinyl acetate resin, polyvinyl butyral resin, etc. These resins may be used alone or in combination of two or more. These resins may be either commercially available or synthetic products. The partially saponified polyvinyl acetate resin is a resin in which polyvinyl acetate resin is partially saponified.

[0071] In the resin other than the high acid value compound, the structural unit represented by the structural formula (1) has hydrophobicity. In addition, the resin having the structural unit represented by the structural formula (1) is preferably soluble in the organic solvent of the modeling liquid and insoluble in water.

[0072] The resin having the structural unit represented by the structural formula (1) may be either a resin further having a structural unit other than the structural unit represented by the structural formula (1), or a resin consisting only of the structural unit represented by the structural formula (1). As the structural unit other than the structural formula (1), for example, a structural unit represented by the following structural formula (3) and a structural unit represented by the following structural formula (4) are preferable. [ka] [ka]

[0073] The structural unit represented by structural formula (3) also has hydrophobicity, which improves the solubility of resins other than high acid value compounds in organic solvents. In addition, the hydroxyl group in the structural unit represented by structural formula (4) improves the affinity with metal particles in the powder layer to which the modeling liquid is applied.

[0074] A polyvinyl acetate resin has a structural unit represented by structural formula (1). On the other hand, a polyvinyl acetate resin is a resin that does not substantially have a structural unit represented by structural formula (3) or a structural unit represented by structural formula (4).

[0075] A partially saponified polyvinyl acetate resin has a structural unit represented by structural formula (1) and a structural unit represented by structural formula (4). On the other hand, a partially saponified polyvinyl acetate resin is a resin that does not have a structural unit represented by structural formula (3).

[0076] A polyvinyl butyral resin is a resin having a structural unit represented by structural formula (1) and a structural unit represented by structural formula (3), or a resin having a structural unit represented by structural formula (1), a structural unit represented by structural formula (3), and a structural unit represented by structural formula (4).

[0077] When the molding liquid contains a rosin compound having an acid value of 120 mgKOH / g or more as the high acid value compound, it is preferable that the molding liquid contains a resin having a structural unit represented by structural formula (1). The combined use of a rosin compound having an acid value of 120 mgKOH / g or more and a resin having a structural unit represented by structural formula (1) is preferable in that the sintered density after sintering is improved, and the strength is improved.

[0078] -Organic solvents- The organic solvent is a liquid component that makes the modeling liquid liquid in a liquid state at room temperature. In addition, the modeling liquid preferably contains an organic solvent, making it a non-aqueous modeling liquid.

[0079] A non-aqueous modeling liquid is a modeling liquid that contains an organic solvent as a liquid component and in which the component with the largest mass among the liquid components is the organic solvent. In addition, a non-aqueous modeling liquid is a modeling liquid in which the content of the organic solvent relative to the content of the liquid components in the modeling liquid is preferably 90.0 mass% or more, and more preferably 95.0 mass% or more.

[0080] Furthermore, the non-aqueous modeling liquid is, for example, a modeling liquid that does not substantially contain water. Since the modeling liquid does not substantially contain water, even if the material constituting the metal particles is a highly active metal (water-restricting material), the modeling liquid can be easily used as the modeling liquid.

[0081] In the present invention, “substantially free of water” means that water is not actively used as a material in the production of the modeling liquid, or that the water content in the modeling liquid is below the detection limit when using a method that is publicly known and in accordance with common technical knowledge.

[0082] When the molding liquid is substantially free of water, the water content is 10.0 mass% or less, preferably 5.0 mass% or less, more preferably 3.0 mass% or less, and even more preferably 1.0 mass% or less, relative to the total mass of the molding liquid, and it is particularly preferable that the molding liquid is free of water. By making the molding liquid substantially free of water, the solubility of the high acid value compound is further improved, and the viscosity of the molding liquid can be further reduced.

[0083] Furthermore, when the modeling liquid is non-aqueous, the solubility of resins other than high acid value compounds, particularly resins having a structural unit represented by structural formula (1), is improved, the viscosity of the modeling liquid is reduced, and the discharge is stabilized.

[0084] As one example, aluminum forms an aluminum hydroxide film when it comes into contact with water, so if the water content in the molding liquid is high, there is a problem that the sintered density of the sintered body decreases. On the other hand, by using a non-aqueous molding liquid, the formation of an aluminum hydroxide film can be suppressed. As another example, aluminum generates hydrogen when it comes into contact with water, so there is a problem that it is difficult to handle, but by using a non-aqueous molding liquid, the generation of hydrogen can also be suppressed.

[0085] The viscosity of the organic solvent is preferably from 5.0 mPa·s to 50.0 mPa·s, and more preferably from 8.0 mPa·s to 30.0 mPa·s, at 25° C. When the viscosity of the organic solvent is from 5.0 mPa·s to 50.0 mPa·s at 25° C., it is easy to reduce the viscosity of the modeling liquid containing the organic solvent, which stabilizes the discharge from the modeling liquid applying means such as an inkjet head, and the accurate discharge of the modeling liquid further improves the bending strength of the modeled object, solidified object, and three-dimensional model precursor in a pre-sintered state, and also improves the dimensional accuracy. The viscosity of the organic solvent can be measured, for example, in accordance with JIS K 7117-2:1999.

[0086] The boiling point of the organic solvent is high, and is preferably 150° C. or higher, and more preferably 180° C. or higher. When the boiling point of the organic solvent is high, drying of the modeling liquid is suppressed. In this specification, the "boiling point of an organic solvent" means the boiling point at 760 mmHg.

[0087] The organic solvent is not particularly limited, but examples thereof include γ-butyrolactone (boiling point: 204° C.), propylene carbonate (boiling point: 242° C.), cyclohexanone (boiling point: 155.6° C.), diethylene glycol dimethyl ether (boiling point: 162° C.), and triethylene glycol dimethyl ether (boiling point: 216° C.). Other examples of the organic solvent 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 octanoate, ethyl acetoacetate, ethyl 3-ethoxypropionate, diethyl oxalate, diethyl malonate, diethyl succinate, diethyl adipate, bis 2-ethylhexyl maleate, triethyl hexyl ester, and ethyl 1-methylbutyrate. Examples of the monomer include acetin, tributyrin, 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, 2-methoxy-1-methylethyl acetate, γ-butyrolactone, propylene carbonate, cyclohexanone, and butyl cellosolve. These monomers may be used alone or in combination of two or more.

[0088] When using a resin having a structural unit represented by structural formula (1), the organic solvent to be used in combination is not particularly limited, but for example, it is preferable to use an organic solvent having at least one structure selected from the group consisting of an alkoxy group, an ether bond, and an ester bond, it is more preferable to use an organic solvent having an ether bond, and it is particularly preferable to use alkylene glycol dialkyl ethers. When using these organic solvents, the solubility of the resin having a structural unit represented by structural formula (1) is further improved.

[0089] In addition, "alkylene glycol dialkyl ethers" are 1 -(OR 2 ) m -OR3 It is expressed as R 1 and R 3 are each independently an alkyl group having 1 to 5 carbon atoms, which may be linear or branched, and preferably has 1 or 2 carbon atoms. 2 represents an alkylene group having 2 to 5 carbon atoms, which may be linear or branched, and more preferably has 2 or 3 carbon atoms. m represents an integer of 1 to 5, more preferably 2 or 3.

[0090] Specific examples of alkylene glycol dialkyl ethers include diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, diethylene glycol ethyl methyl ether, diethylene glycol butyl methyl ether, etc. Among these, as the alkylene glycol dialkyl ethers, diethylene glycol dimethyl ether and triethylene glycol dimethyl ether are preferred, and triethylene glycol dimethyl ether is more preferred.

[0091] When a resin having a structural unit represented by structural formula (2) is used as a resin other than the high acid value compound, it is preferable that the organic solvent used in combination is a polar solvent. Specifically, it is preferable to use at least one selected from "component 1" which is a group consisting of cyclic esters (lactones), cyclic ketones, and alkylene glycol monoalkyl ethers, and it is more preferable to use at least one selected from "component 2" which is a group consisting of alkylene glycol dialkyl ethers in addition to at least one selected from "component 1". When these organic solvents are used, the solubility of the resin having the structural unit represented by structural formula (2) is further improved. In addition, from the viewpoint of further improving the solubility of the resin having the structural unit represented by structural formula (2), it is preferable that "component 1" is a group consisting of cyclic esters (lactones) and cyclic ketones. Specific examples of "component 1" which is a group consisting of cyclic esters (lactones), cyclic ketones, and alkylene glycol monoalkyl ethers include γ-butyrolactone, propylene carbonate, and cyclohexanone.

[0092] Specific examples of "component 2" which is a group consisting of alkylene glycol dialkyl ethers include diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, diethylene glycol ethyl methyl ether, diethylene glycol butyl methyl ether, etc. Among these, "component 2" which is a group consisting of alkylene glycol dialkyl ethers is preferably diethylene glycol dimethyl ether and triethylene glycol dimethyl ether.

[0093] "Alkylene glycol monoalkyl ethers" means R 4 -(OR 5 ) n It is represented by -OH. 4 R is an alkyl group having 1 to 5 carbon atoms, and may be linear or branched. 5 is an alkylene group having 2 to 5 carbon atoms, which may be linear or branched. n is an integer of 1 to 5.

[0094] The content of the organic solvent is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 60.0% by mass or more and 95.0% by mass or less, and more preferably 70.0% by mass or more and 95.0% by mass or less, based on the total mass of the molding liquid. If the content is 60.0% by mass or more and 95.0% by mass or less, the solubility of the high acid value compound is further improved, and the viscosity of the molding liquid can be further reduced, so that the molding liquid can be appropriately discharged, for example, by an inkjet method. In addition, the drying of the molding liquid in the molding liquid applying means such as an inkjet head is suppressed, and a molding liquid with excellent discharge stability can be applied.

[0095] -Additives- The molding liquid may contain surfactants, drying inhibitors, viscosity adjusters, penetrants, antifoaming agents, pH adjusters, preservatives, antifungal agents, colorants, preservatives, stabilizers, and the like, as appropriate, depending on the purpose.

[0096] -Method of manufacturing modeling fluid- The method for producing the modeling liquid is not particularly limited and can be appropriately selected depending on the purpose. For example, the materials may be mixed and stirred.

[0097] <Heating process> The heating step is a step of heating the powder layer to which the modeling liquid has been applied. This removes the organic solvent and other substances contained in the modeling liquid remaining in the powder layer. A solidified object can be formed by the heating step.

[0098] The heating temperature in the heating step is preferably equal to or lower than the boiling point of the organic solvent at 760 mmHg. This allows the organic solvent remaining in the powder layer to be volatilized and removed. If the organic solvent remains in the heating step, the strength of the solidified product may decrease.

[0099] The bending strength of the solidified product obtained by the heating step is not particularly limited, but is preferably 3.0 MPa or more, more preferably 4.0 MPa or more, and even more preferably 5.0 MPa or more. If the bending strength of the solidified product is 3.0 MPa or more, the solidified product is less likely to break, and a three-dimensional object precursor and a three-dimensional object having a desired shape can be suitably produced. The higher the bending strength of the solidified product, the better, and there is no particular limit to the condition value.

[0100] The bending strength of the solidified material obtained in the heating process can be measured using a universal testing machine (Autograph, Model AG-I, manufactured by Shimadzu Corporation) with a 1 kN load cell and a three-point bending jig. The bending strength of the solidified material obtained in the heating process is the maximum stress at the breaking point, which is plotted against the amount of strain when the load point is displaced at a speed of 1 mm / min with a support distance of 24 mm.

[0101] <Degreasing process> The degreasing process is a process for degreasing the powder layer to which the modeling liquid has been applied. This makes it possible to obtain a degreased body from which organic compounds and the like derived from the modeling liquid in the three-dimensional object precursor have been removed. Note that the degreasing process may volatilize and remove not only the organic compounds contained in the three-dimensional object precursor but also the removing liquid.

[0102] The degreasing step can be carried out in a vacuum atmosphere, an argon (Ar) atmosphere, a hydrogen (H2) atmosphere, a nitrogen (N2) atmosphere, or the like.

[0103] The degreasing step preferably includes heating the precursor of a three-dimensional object for a certain period of time at a temperature equal to or lower than the boiling point of the organic solvent at 760 mmHg to a temperature equal to or higher than the decomposition temperature of the organic matter contained in the powder layer, and lower than the melting point or solidus temperature of the material (metal) constituting the metal particles, thereby decomposing and removing the organic matter. More preferably, the degreasing step is performed at a temperature of 200°C or higher and 570°C or lower.

[0104] In the degreasing step, when the temperature is raised from a temperature below the boiling point of the organic solvent at 760 mmHg to a temperature above the decomposition temperature of the organic matter contained in the powder layer, the high acid value compound is activated without being decomposed in the early stage of the temperature rise (for example, around 200°C, preferably 200°C ± 30°C), so that the oxide film on the surface of the metal particles can be preferably thinned or removed. In the degreasing step, when the temperature is raised from a temperature below the boiling point of the organic solvent at 760 mmHg to a temperature above the decomposition temperature of the organic matter contained in the powder layer, the organic matter in the high acid value compound is decomposed in the latter half of the temperature rise (for example, 350°C to 570°C). As a result, the organic residue derived from the high acid value compound, which is a sintering inhibitor, can be removed or reduced, and the high acid value compound does not inhibit sintering, so that the sintering density of the sintered body can be improved.

[0105] Specifically, the organic matter may be a resin (binder component) other than the high acid value compound. Therefore, in the degreasing process, it is preferable to decompose the resin at a temperature higher than the thermal decomposition temperature of the resin other than the high acid value compound and lower than the melting point or solidus temperature of the metal particles. Depending on the resin component other than the high acid value compound used, it is also possible to set multiple heating and holding temperatures.

[0106] The solidus temperature can be appropriately selected depending on the material constituting the metal particles. For example, the solidus temperature is about 570° C. when AlSi10Mg particles are used. The solidus temperature can be estimated by phase diagram calculations under thermodynamic equilibrium.

[0107] The heating time in the degreasing step is not particularly limited, but is preferably 1 hour to 10 hours.

[0108] <Sintering process> In the sintering step, the degreased powder layer is sintered to obtain a sintered body. The degreasing step and the sintering step may be performed successively.

[0109] Specifically, the sintering process is a process in which the degreased body is heated for a certain period of time using a sintering means at a temperature that is equal to or higher than the solidus temperature and equal to or lower than the liquidus temperature of the metal material that constitutes the metal particles, thereby integrating the metal material that constitutes the metal particles.

[0110] More specifically, the sintering process involves heating the degreased three-dimensional object precursor to a temperature between the liquidus temperature and the solidus temperature at a rate of 1°C / hour to 200°C / hour (the heating rate can be changed during the process), and then holding the temperature for about 1 hour to 10 hours. After the sintering process, the inside of the sintering device is cooled, and the molded object is removed.

[0111] Specifically, the maximum temperature reached in the sintering step is preferably a temperature at which 10% to 50% of the metal material is produced in a liquid phase.

[0112] The sintering step can be carried out in a vacuum atmosphere, an argon (Ar) atmosphere, a hydrogen (H2) atmosphere, a nitrogen (N2) atmosphere, or the like.

[0113] The liquidus temperature can be appropriately selected depending on the material constituting the metal particles. For example, the liquidus temperature is about 600° C. when AlSi10Mg particles are used. The liquidus temperature can be estimated by phase diagram calculations under thermodynamic equilibrium.

[0114] The sintered body has a high sintered density. In the present invention, "high sintered density" means that the relative density of the three-dimensional object (sintered body) is high with respect to the density of the metal material constituting the three-dimensional object (sintered body). The relative density of the three-dimensional object (sintered body) is preferably 93% or more, and more preferably 97% or more. Specifically, the relative density can be calculated by the following formula: Furthermore, the density of the metal material and the density of the three-dimensional object (sintered body) can be measured, for example, by an automatic specific gravity meter (manufactured by Toyo Machine Works, Ltd.). Relative density (%) = density of sintered body / density of metal material x 100

[0115] <Other processes> The other steps are not particularly limited and can be appropriately selected depending on the purpose. For example, there are a lamination step, an excess powder removal step, a post-treatment step, and the like.

[0116] <<Lamination process>> The lamination process is a process for forming a shaped object by sequentially repeating the powder layer formation process and the modeling liquid application process.

[0117] The lamination process includes a powder layer forming process and a modeling liquid applying process, thereby forming an area in the powder layer to which the modeling liquid has been applied. Furthermore, the lamination process includes a process of laminating powder on the powder layer having an area to which the modeling liquid has been applied (powder layer forming process), and a process of applying the modeling liquid onto the powder layer (modeling liquid applying process), thereby forming an area to which the modeling liquid has been applied in the newly laminated powder layer. At this time, the area to which the modeling liquid has been applied that is generated in the uppermost laminated powder layer is continuous with the area to which the modeling liquid has been applied in the powder layer below it. As a result, an area to which the modeling liquid has been applied that is twice the thickness of the powder layer is obtained.

[0118] <<Excess powder removal process>> The excess powder removing step is a step of removing the excess powder adhering to the solidified material to obtain a three-dimensional object precursor.

[0119] In addition, the excess powder removal step preferably includes at least one step selected from the group consisting of a step of removing excess powder from the solidified material by an excess powder removal means such as an air blower, and a step of removing excess powder from the solidified material by immersing the solidified material in a removal liquid, and more preferably includes both steps.

[0120] The solidified material after the heating step is in a state where it is buried in the powder. When the solidified material is taken out from this buried state, excess powder adheres to the surface and inside of the solidified material, and it is difficult to remove them easily. In addition, it is even more difficult when the surface shape of the solidified material is complex or the internal structure of the solidified material is like a flow path. Since the strength of the pre-sintered shaped material formed by the general binder jetting method is not high, if the pressure of the air blow by the air blowing means is increased, the shaped material may collapse. On the other hand, the solidified material formed using the shaping liquid has improved bending strength and has a strength that can withstand the pressure of the air blow. At this time, the strength of the solidified material is preferably 4.0 MPa or more, more preferably 5.0 MPa or more, and even more preferably 6.0 MPa or more in three-point bending stress. The higher the three-point bending stress, the better, and the condition value is not particularly limited.

[0121] -Removal liquid- The removal liquid contains an organic solvent and, if necessary, further contains other components. In order to distinguish between the organic solvent contained in the modeling liquid and the organic solvent contained in the removal liquid, the organic solvent contained in the modeling liquid may be referred to as a “first organic solvent” and the organic solvent contained in the removal liquid may be referred to as a “second organic solvent.”

[0122] Examples of the second organic solvent include ketones, halogens, alcohols, esters, ethers, hydrocarbons, glycols, glycol ethers, glycol esters, pyrrolidones, amides, amines, carbonates, etc. These may be used alone or in combination of two or more.

[0123] Examples of the ketone include acetone, methyl ethyl ketone, diethyl ketone, methyl propyl ketone, methyl isobutyl ketone, methyl amyl ketone, cyclohexanone, isophorone, acetophenone, and diacetone alcohol.

[0124] Examples of halogens include methylene chloride, trichloroethylene, perchloroethylene, HCFC141-b, HCFC-225, 1-bromopropane, chloroform, and orthodichlorobenzene.

[0125] Examples of the alcohol include methanol, ethanol, butanol, isobutanol, isopropyl alcohol, normal propyl alcohol, tertiary butanol, secondary butanol, 1,3-butanediol, 1,4-butanediol, 2-ethylhexanol, and benzyl alcohol.

[0126] 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, amyl 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 dibasic acid esters (DBE).

[0127] 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, and dipropylene glycol monomethyl ether.

[0128] Examples of hydrocarbons include benzene, toluene, xylene, solvent naphtha, normal hexane, isohexane, cyclohexane, ethylcyclohexane, methylcyclohexane, cyclohexene, cycloheptane, cyclopentane, heptane, pentamethylbenzene, pentane, methylcyclopentane, normal heptane, isooctane, normal decane, normal pentane, isopentane, mineral spirits, dimethyl sulfoxide, and linear alkylbenzene.

[0129] Examples of glycols include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, and dimethoxytetraethylene glycol.

[0130] Examples of glycol esters include ethylene glycol monoethyl ether acetate and diethylene glycol monobutyl ether acetate.

[0131] Examples of glycol ethers include methyl carbitol, ethyl carbitol, butyl carbitol, and methyl triglycol.

[0132] Examples of pyrrolidone include 2-pyrrolidone, N-ethyl-2-pyrrolidone, and N-methyl-2-pyrrolidone.

[0133] Examples of the amide include dimethylformamide, dimethylacetamide, and formamide.

[0134] Examples of the amine include tetramethylethylenediamine, N,N-diisopropylethylamine, ethylenediamine, triethylamine, diethylamine, aniline, pyrrolidine, piperidine, morpholine, pyrrole, pyridine, pyridazine, oxazole, thiazole, and 1,3-dimethyl-2-imidazolidinone.

[0135] Examples of carbonate esters include diethyl carbonate, dimethyl carbonate, propylene carbonate, and ethyl methyl carbonate.

[0136] The content of the second organic solvent in the removal liquid is not particularly limited, but is preferably 90.0% by mass or more, and more preferably 95.0% by mass or more. The removal liquid may consist of only the second organic solvent.

[0137] Examples of other components in the removal solution include additives such as surfactants, antifoaming agents, antiseptics and antifungals, pH adjusters, chelating agents, and rust inhibitors. The contents of other components in the removal solution are not particularly limited and can be appropriately selected depending on the purpose.

[0138] <<Post-processing process>> The post-treatment step is a step of performing post-treatment on the sintered body. The post-treatment is not particularly limited and can be appropriately selected depending on the purpose. Examples of the post-treatment include surface protection treatment and painting.

[0139] The method for manufacturing a three-dimensional object can be suitably carried out by the apparatus for manufacturing a three-dimensional object of the present invention.

[0140] (3D object manufacturing equipment) The apparatus for manufacturing a three-dimensional object of the present invention has a powder layer forming means for forming a powder layer containing a powder including metal particles, and a modeling liquid applying means for applying to the powder layer a modeling liquid containing an organic solvent and at least one high acid value compound selected from the group consisting of rosin compounds, styrene compounds, and acrylic compounds, having an acid value of 120 mgKOH / g or more, and preferably further has a heating means, a degreasing means, and a sintering means, and further has other means as necessary.

[0141] The manufacturing apparatus for a three-dimensional object of the present invention can suitably execute the manufacturing method for a three-dimensional object of the present invention. Therefore, the powder layer forming means, the modeling liquid applying means, the heating means, the degreasing means, the sintering means, and other means can suitably execute the powder layer forming step, the modeling liquid applying step, the heating step, the degreasing step, the sintering step, and other steps, respectively, and therefore detailed descriptions thereof will be omitted.

[0142] <Powder layer forming means> The powder layer forming means is a means for forming a powder layer containing powder including metal particles. Examples of the powder layer forming means include a counter rotating mechanism (counter roller), a brush, a roller, a blade, and a pressing member.

[0143] The powder may be contained in a powder container, which is a member such as a container in which the powder is contained, and examples of the member include a reservoir, a bag, a cartridge, and a tank.

[0144] <Modeling liquid application means> The molding liquid application means is a means for applying a molding liquid to the powder layer, the molding liquid containing an organic solvent and a high acid value compound, which is at least one type selected from the group consisting of rosin compounds, styrene compounds, and acrylic compounds, having an acid value of 120 mgKOH / g or more.

[0145] When the inkjet method is used as a method for discharging the modeling liquid, the modeling liquid applying means that applies the modeling liquid by discharging it is an inkjet head having a nozzle that discharges the modeling liquid.

[0146] The modeling liquid supplied to the modeling liquid supplying means may be accommodated in a modeling liquid accommodation unit. The modeling liquid accommodation unit is a member such as a container in which the modeling liquid is accommodated, and examples of the member include a storage tank, a bag, a cartridge, and a tank.

[0147] <Heating means> The heating means is a means for heating the powder layer to which the modeling liquid has been applied. Examples of the heating means include a known dryer and a thermo-hygrostat.

[0148] <Degreasing method> The degreasing means is a means for degreasing the powder layer to which the modeling liquid has been applied. The degreasing means may be, for example, a known sintering device, electric furnace, or the like.

[0149] <Sintering method> The sintering means is a means for sintering the degreased powder layer. The sintering means may be, for example, a known sintering device, but may be the same means as the degreasing means.

[0150] Here, an embodiment of the manufacturing method of a three-dimensional object and the manufacturing apparatus of a three-dimensional object of the present invention will be described in detail with reference to the drawings. Note that in each drawing, the same components are given the same reference numerals, and duplicated explanations may be omitted. In addition, the number, position, shape, etc. of the following components are not limited to the present embodiment, and the number, position, shape, etc. may be any number, position, shape, etc. that is preferable for implementing the present invention.

[0151] [Embodiment of the method for manufacturing a molded object] FIG. 1 is a schematic diagram of a modeling apparatus 100 according to one embodiment of the present invention. The modeling apparatus 100 includes a powder layer modeling unit 1 and a modeling liquid application unit 5. The powder layer modeling unit 1 models a powder layer 31 containing powder 20. The modeling liquid application unit 5 applies modeling liquid 10 to the powder layer 31 to form a modeling layer 30. The modeling apparatus 100 stacks a plurality of modeling layers 30 to form a modeled object.

[0152] The powder layer molding section 1 has a powder tank 11 and a lamination unit 16. The powder tank 11 has a supply tank 21, a modeling tank 22, a supply stage 23, a modeling stage 24, and a surplus powder tank 25. The powder tank 11 has a box shape. The tops of the supply tank 21, the modeling tank 22, and the surplus powder tank 25 are open. The lamination unit 16 has a flat section 12 and a powder removal section 13.

[0153] The supply tank 21 is a tank that supplies the powder 20 to the modeling tank 22. The supply tank 21 also holds the powder 20 to be supplied to the modeling tank 22. A supply stage 23 is provided at the bottom of the supply tank 21. The supply stage 23 moves up and down in the vertical direction (Z direction). The side of the supply stage 23 is disposed so as to contact the inner side of the supply tank 21.

[0154] The powder 20 required for modeling is supplied to the modeling tank 22 from the supply tank 21. In the supply tank 21, a powder layer 31 and a modeling layer 30 are formed. Furthermore, in the modeling tank 22, a plurality of modeling layers 30 are stacked to form a model.

[0155] A supply stage 23 and a modeling stage 24 are provided at the bottom of the supply tank 21 and the modeling tank 22, respectively, and move up and down in the vertical direction (Z direction). The side of the modeling stage 24 is disposed so as to contact the inner side of the modeling tank 22. The upper surfaces of the supply stage 23 and the modeling stage 24 are kept horizontal.

[0156] The surplus powder tank 25 is a tank that holds the surplus powder 20 among the powder 20 flattened by the flat portion 12 when forming the powder layer 31. The bottom of the surplus powder tank 25 may be provided with a means for sucking the powder 20, or may be a means for removing the surplus powder tank 25. The surplus powder tank 25 is disposed next to the modeling tank 22. The surplus powder 20 held in the surplus powder tank 25 may be returned to the supply tank 21, or may be returned to the supply tank 21 via a powder supplying device. The powder supplying device may be disposed above the supply tank 21, and supplies the powder 20 to the supply tank 21 before modeling begins or when the amount of powder 20 in the supply tank 21 decreases. Note that the powder tank 11 is described as having two tanks, the supply tank 21 and the modeling tank 22, but it may be only the modeling tank 22, and powder may be supplied to the modeling tank 22 from the powder supplying device.

[0157] Methods for transporting the powder 20 from the powder supplying device to the supply tank 21 include a screw conveyor method using a screw, and a pneumatic transport method using air.

[0158] The flat part 12 flattens the modeling layer 30 and the powder layer 31. The flat part 12 flattens the modeling layer 30 by rotating the recoater as a rotating body. The flat part 12 rotates to supply the powder 20 from the supply stage 23 of the supply tank 21 to the modeling tank 22, forming the powder layer 31. The flat part 12 moves back and forth in the Y direction along the stage surface (the surface on which the powder 20 is loaded) of the modeling stage 24. More specifically, the flat part 12 moves horizontally from the outside of the supply tank 21 to pass above the supply tank 21 and the modeling tank 22. As a result, the powder 20 is transferred and supplied onto the modeling tank 22, and the flat part 12 flattens the powder 20 while passing over the modeling tank 22, forming the powder layer 31. The flat part 12 is a member longer than the inner dimensions of the modeling tank 22 and the supply tank 21. Note that the flat part 12 may be a blade or a bar as a plate-shaped member.

[0159] Powder removal part 13 removes powder adhering to flat part 12. Powder removal part 13 moves together with flat part 12 while in contact with the peripheral surface of flat part 12.

[0160] The modeling liquid applying unit 5 includes a carriage 51 and a head 52. The head 52 applies the modeling liquid 10 to the powder layer 31. The head 52 is, for example, an inkjet head, and is provided with a nozzle row in which a plurality of nozzles are arranged. A colored model may be formed by applying a cyan modeling liquid, a magenta modeling liquid, a yellow modeling liquid, and a black modeling liquid, or a modeling liquid of one color may be applied from a plurality of nozzles. The modeling liquid may be applied by an inkjet method or a dispenser method. At least one head 52 is mounted on the carriage 51, and moves back and forth in the X (main scanning), Y (sub-scanning), and Z directions by a motor, a guide member, or the like.

[0161] Next, an embodiment of the method for manufacturing a three-dimensional object of the present invention (modeling flow) will be described in more detail with reference to Figs. 2A to 2E. Figs. 2A to 2E are schematic diagrams showing one example or another example of the operation of the modeling apparatus 100 according to an embodiment of the present invention. The configuration of the modeling apparatus 100 according to an embodiment of the present invention shown in Figs. 2A to 2E is the same as that of the modeling apparatus 100 according to an embodiment of the present invention in Fig. 1.

[0162] First, a state in which the first modeling layer 30 is formed on the modeling stage of the modeling tank will be described. When the next powder layer is to be formed on the first modeling layer 30, the supply stage 23 of the supply tank 21 is raised and the modeling stage 24 of the modeling tank 22 is lowered, as shown in Fig. 2A. At this time, the lowering distance of the modeling stage 24 is set so that the distance (layer pitch) between the upper surface of the first modeling layer 30 in the modeling tank 22 and the lower part (lower tangent part) of the flat part 12 is Δt1.

[0163] In one embodiment of the method for manufacturing a three-dimensional object of the present invention, the flat portion 12 is disposed so as to create a gap with respect to the upper end surfaces of the supply tank 21 and the modeling tank 22. Therefore, when the powder 20 is transferred and supplied to the modeling tank 22 and flattened, the upper surface of the modeling layer 30 is located at a position higher than the upper end surfaces of the supply tank 21 and the modeling tank 22. This reliably prevents the flat portion 12 from contacting the upper end surfaces of the supply tank 21 and the modeling tank 22, reducing damage to the flat portion 12. If the surface of the flat portion 12 is damaged, streaks will occur on the surface of the powder layer 31 (see FIG. 2D) supplied to the modeling tank 22, making it easy for flatness to decrease.

[0164] Next, as shown in FIG. 2B, the powder 20 arranged at a position higher than the upper end surface of the supply tank 21 is moved toward the modeling tank 22 while rotating the flat portion 12 in the direction of the arrow, thereby transferring and supplying the powder 20 to the modeling tank 22 (powder supply). Furthermore, as shown in FIG. 2C, the flat portion 12 is moved parallel to the stage surface of the modeling stage 24 of the modeling tank 22, and a powder layer 31 having a predetermined thickness Δt1 is formed on the modeling tank 22 of the modeling stage 24 (flattening). At this time, the surplus powder 20 not used for forming the powder layer 31 falls into the surplus powder tank 25. After forming the powder layer 31, the flat portion 12 is moved toward the supply tank 21 and returned (returned) to the initial position (origin position) as shown in FIG. 2D.

[0165] Here, the flat part 12 is adapted to be able to move while keeping the distance between the upper end surface of the modeling tank 22 and the supply tank 21 constant. By being able to move while keeping the distance constant, the flat part 12 can transport the powder 20 onto the modeling tank 22, while forming a powder layer 31 of uniform thickness h (corresponding to the layer pitch Δt1) on the modeling tank 22 or on the already formed modeling layer 30. In the following, the thickness h of the powder layer 31 and the layer pitch Δt1 may be described without distinction, but unless otherwise specified, they are the same thickness and have the same meaning. The thickness h of the powder layer 31 may also be obtained by actually measuring it, and in this case, it is preferable to use the average value of a plurality of points.

[0166] Thereafter, as shown in Fig. 2E, droplets of the modeling liquid 10 are ejected from the head 52 of the liquid ejection unit to form a modeling layer 30 of a desired shape on the second powder layer 31. Next, the powder layer forming process and the modeling liquid applying process are repeated to form and stack a new modeling layer 30. At this time, the new modeling layer 30 and the modeling layer 30 below it are integrated. Thereafter, the powder layer forming process and the modeling liquid applying process are further repeated to complete the stacked product.

[0167] FIG. 3 is a schematic diagram showing a system for forming a three-dimensional object according to one embodiment of the present invention. The modeling system 500 according to an embodiment of the present invention includes a modeling device 100, a heating device 200, an excess powder removing device 300, and a sintering device 400. The modeling device 100 models a model. The heating device 200 heats the model formed by the modeling device 100. The excess powder removing device 300 removes excess powder adhering to the model heated by the heating device 200. The excess powder removing device 300 may be, for example, an air blower. The sintering device 400 sinters the model from which the excess powder has been removed. The sintering device 400 may degrease the model before sintering. The modeling system 1 may be configured with four devices, with the modeling device 100, the heating device 200, the excess powder removing device 300, and the sintering device 400 being separate, or may be configured with the four devices integrated into one device, or may be configured with some of the functions installed in the modeling device 100 or the sintering device 400. Furthermore, at least a part of the functions of the heating device 200 or the excess powder removing device 300 may be omitted as appropriate.

[0168] FIG. 4 is a flowchart showing a method for manufacturing a three-dimensional object according to one embodiment of the present invention. First, a powder layer containing powder is formed by the modeling apparatus 100 (S1). Next, the modeling apparatus 100 applies modeling liquid to the powder layer (S2). The modeling apparatus 100 forms a model by sequentially repeating the formation of a powder layer and the application of modeling liquid (S3). Next, the heating apparatus 200 heats the model formed in S3 (S4). The excess powder removing apparatus 300 removes excess powder from the model heated in S4 to obtain a molded body (S5). Then, the sintering apparatus 400 degreases the molded body obtained in S5 (S6). Finally, the sintering apparatus 400 sinters the degreased body (S7).

[0169] (3D model) The three-dimensional object of the present invention is manufactured by the three-dimensional object manufacturing method or the three-dimensional object manufacturing apparatus of the present invention, and therefore has a high sintering density.

[0170] The uses of the three-dimensional objects are not particularly limited and can be appropriately selected depending on the purpose. For example, they can be suitably used for meters or operation panels of automobiles, office automation equipment, electrical equipment, electronic equipment, cameras, etc., various parts, daily necessities, prototypes, etc.

[0171] (Modeling liquid for manufacturing three-dimensional objects) The modeling liquid for producing a three-dimensional object of the present invention is a modeling liquid for producing a three-dimensional object that is applied to a powder layer containing a powder that contains metal particles, and contains a high acid value compound having an acid value of 120 mg KOH / g or more, which is at least one type selected from the group consisting of rosin compounds, styrene compounds, and acrylic compounds, an organic solvent, and further contains other components as necessary.

[0172] The components contained in the modeling liquid for producing a three-dimensional object of the present invention are the same as those described in the section <<Modeling liquid>> of (Production method of a three-dimensional object), and therefore a detailed description thereof will be omitted.

[0173] A three-dimensional object obtained by using the molding liquid for producing a three-dimensional object has a high sintering density and high strength.

[0174] (3D modeling kit) The kit for producing a three-dimensional object of the present invention contains the modeling liquid for producing a three-dimensional object of the present invention and a powder containing metal particles, and may further contain other components such as a removal liquid, if necessary.

[0175] In the kit for producing a three-dimensional object, the modeling liquid for producing a three-dimensional object, the powder containing metal particles, and other components may be present in an integrated state or each may be present independently. For example, a modeling liquid container for producing a three-dimensional object, which contains the modeling liquid for producing a three-dimensional object, and a powder container for producing a three-dimensional object, which contains the powder containing metal particles, may be integrated together. Even if the modeling liquid for producing a three-dimensional object, the powder containing metal particles, and other components are each contained in separate containers, the kit for producing a three-dimensional object of the present invention is included in the kit if it is assumed that the modeling liquid for producing a three-dimensional object, the powder containing metal particles, and other components as necessary will be used in combination, or if it essentially induces the modeling liquid for producing a three-dimensional object, the powder containing metal particles, and other components as necessary to be used in combination. EXAMPLES

[0176] The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to these examples and comparative examples.

[0177] Example 1 <Preparation of modeling liquid> The materials shown in Table 1 below were heated at 70° C. and stirred with a magnetic stirrer for 4 hours. After stirring for 4 hours, the heating was stopped and stirring was continued until the temperature reached room temperature (25±5° C.), thereby preparing the modeling liquid of Example 1. The content of each material in Table 1 below is shown in mass %.

[0178] <Manufacturing of 3D objects> Using AlSi1Mg (Si1MgBB, manufactured by Toyo Aluminum K.K.) as a powder containing metal particles and the prepared modeling liquid, two types of three-dimensional model precursors were manufactured as follows: a rectangular pattern having a length of 40 mm, a width of 10 mm, and a thickness of 3 mm (hereinafter sometimes referred to as the "short sample"), and a rectangular pattern having a length of 100 mm, a width of 10 mm, and a thickness of 3 mm (hereinafter sometimes referred to as the "long sample").

[0179] <<Powder layer formation process>> Using a modeling apparatus 100 according to one embodiment of the present invention shown in Figure 1, powder 20 containing metal particles was transferred from a supply tank 21 to a modeling tank 22, and a powder layer containing powder containing metal particles and having an average thickness of 100 μm was formed on a modeling stage 24.

[0180] <<Modeling liquid application process>> The modeling liquid 10 was applied (discharged) from the nozzle of a known inkjet head 52 onto the surface of the powder layer containing the powder containing metal particles formed in the powder layer formation process. At this time, the discharge area of ​​the modeling liquid 10 was shaped as a short sample with a length of 40 mm and a width of 10 mm, and a long sample with a length of 100 mm and a width of 10 mm, and the modeling layer 30 was formed.

[0181] <<Lamination process>> The powder layer forming step and the modeling liquid applying step were repeated until the modeling layer 30 reached the predetermined total average thickness of 3 mm, thereby obtaining a modeled object.

[0182] <<Heating process and excess powder removal process>> The object obtained in the lamination step was vacuum-dried at a temperature equal to or lower than the boiling point of the organic solvent at 760 mmHg using a heating device 200 to obtain a solidified product. Excess powder was removed from the dried solidified product using an excess powder removing device 300 to obtain a three-dimensional object precursor.

[0183] <<Degreasing process>> The three-dimensional object precursor obtained in the heating step was heated in a sintering device 400 at a temperature equal to or lower than the solidus temperature (about 570° C.) of the metal material constituting the metal particles, to obtain a degreased body.

[0184] <<Sintering process>> The degreased body obtained in the degreasing process was heated in a sintering device 400 at a temperature above the solidus temperature (approximately 570°C) and below the liquidus temperature (approximately 600°C) of the metal material constituting the metal particles to obtain a three-dimensional object that is a sintered body.

[0185] (Examples 2 to 8 and Comparative Examples 1 to 7) In the <Preparation of modeling liquid> of Example 1, except that the materials were changed as shown in Table 1 or Table 2 below, the modeling liquid was prepared and a three-dimensional object was manufactured in the same manner as in Example 1, and the modeling liquids, three-dimensional modeling precursors, and three-dimensional objects of Examples 2 to 8 and Comparative Examples 1 to 7 were obtained.

[0186] [evaluation] Using the modeling liquid, 3D modeling precursor, or 3D object obtained in Examples 1 to 8 and Comparative Examples 1 to 7, the following methods were used to measure or evaluate the "viscosity of the modeling liquid," "glass transition temperature (Tg) of the high acid value compound," "bending strength of the 3D object precursor," "deflection of the 3D object precursor under high temperature and high humidity," and "relative density of the 3D object (sintered body)." The measurement or evaluation results are shown in Tables 1 and 2 below.

[0187] <<Measuring the viscosity of the molding liquid>> The modeling liquid was measured using a cone-plate type rotational viscometer (VISCOMETER TVE-22L, manufactured by Toki Sangyo Co., Ltd.). The temperature inside the measurement container was fixed at 25°C using a high-temperature circulating bath, and a cone rotor (1°34' x R24) was used.

[0188] <<Measurement of glass transition temperature (Tg) of high acid value compounds>> 1 g of the modeling liquid was weighed into an aluminum cup and heated on a hot stirrer at 150°C for 6 hours to obtain a dried product. A portion of the dried product was scraped off from the aluminum cup and measured using a differential scanning calorimetry (DSC) device (DSC2500, manufactured by TA Instruments Japan, Inc.) with a profile in which heating and cooling were performed a total of four times. Specifically, heating was performed in the range from -30°C to 200°C (first time), cooling to -30°C (second time), heating to 200°C (third time), and cooling to -30°C (fourth time). The data from the third heating was taken as the glass transition temperature (Tg) of the high acid value compound and evaluated based on the following evaluation criteria. [Evaluation Criteria] A: Tg is 60℃ or higher B: Tg is 50℃ or higher and less than 60℃ C: Tg is 45℃ or higher and less than 50℃ D: Tg is less than 45°C

[0189] <<Bending strength of precursor of 3D object>> The bending strength of the solidified product obtained in the heating process and the excess powder removing process was measured and evaluated based on the following evaluation criteria. To measure the bending strength of the three-dimensional object precursor, a three-dimensional object precursor (short sample) with a length of 40 mm, width of 10 mm, and thickness of 3 mm was used, and a universal testing machine (Autograph, Model AG-I, manufactured by Shimadzu Corporation) was used, along with a 1 kN load cell and a three-point bending jig. The distance between the supports was set to 24 mm, and the stress when the load point was displaced at a speed of 1 mm / min was plotted against the amount of strain, and the stress at the breaking point was taken as the maximum stress. [Evaluation Criteria] A: Bending strength is 5.0MPa or more B: Bending strength is 4.0 MPa or more and less than 5.0 MPa C: Bending strength is 3.0 MPa or more and less than 4.0 MPa D: Bending strength is less than 3.0 MPa

[0190] <<Distortion of precursors of 3D objects under high temperature and humidity>> A three-dimensional object precursor (long sample) with a length of 100 mm, width of 10 mm, and thickness of 3 mm was stored in a small environmental tester (SH-222, manufactured by Espec Corporation) in a posture in which both ends were supported at 5 mm from both ends, and it was confirmed whether or not bending (sagging near the center) occurred in the center of the three-dimensional object precursor. The amount of bending was confirmed by placing a straight stainless steel scale on the three-dimensional object precursor and confirming whether or not there was a gap between the three-dimensional object precursor and the straight stainless steel scale in the center of the three-dimensional object precursor. In addition to confirming the amount of bending, it was also confirmed whether or not there was deformation (change in shape other than bending) in the three-dimensional object precursor. The temperature inside the small environmental tester was operated at a constant value of 40°C and humidity of 60%, and bending and deformation were confirmed by taking out the sample after 1 day, 2 weeks, 4 weeks, and 5 weeks of storage. When bending or deformation occurred in the center of the three-dimensional object precursor, it was evaluated based on the following evaluation criteria, and then the observation was terminated. [Evaluation Criteria] A: No bending or deformation after 4 weeks or more B: No bending or deformation within 2 to 4 weeks C: Deformation within 2 weeks

[0191] <<Relative density of three-dimensional objects (sintered bodies)>> The density of the AlSi1Mg powder containing metal particles before the powder layer forming step and the density of the three-dimensional object (sintered body) were measured using an automatic specific gravity meter (manufactured by Toyo Machine Works, Ltd.). The relative density of the three-dimensional object (sintered body) with respect to the density of the metal material constituting the three-dimensional object (sintered body) was calculated by the following formula, and evaluated based on the following evaluation criteria. Relative density (%) = density of sintered body / density of AlSi1Mg × 100 [Evaluation Criteria] A: Relative density is 97% or more B: Relative density is 93% or more but less than 97% C: Relative density is less than 93%

[0192] [Table 1]

[0193] [Table 2]

[0194] From Examples 1 to 8, it was found that by using a modeling liquid containing at least one high acid value compound selected from the group consisting of rosin compounds, styrene compounds, and acrylic compounds, each having an acid value of 120 mgKOH / g or more, a high sintering density was obtained even for an aluminum alloy with a low Si content, such as AlSi1Mg. Furthermore, these high acid value compounds provided sufficient strength for the three-dimensional model precursor.

[0195] From Comparative Example 1, in the case of an aluminum alloy such as AlSi1Mg, when the molding liquid did not contain a high acid value compound having an acid value of 120 mgKOH / g or more, the sintered density was low.

[0196] Comparative Examples 2 and 3 show that rosin compounds with low acid values ​​of less than 120 mgKOH / g had lower sintering densities than rosin compounds with high acid values ​​of 120 mgKOH / g or more.

[0197] Similarly, Comparative Examples 4, 5, and 6 showed that styrene-acrylic resins and styrene resins with low acid values ​​of less than 120 mgKOH / g had lower sintering densities than styrene compounds or acrylic compounds with high acid values ​​of 120 mgKOH / g or more.

[0198] From Comparative Example 7, even if the compound has a high acid value of 120 mgKOH / g or more, in the case of fatty acid, the strength of the three-dimensional object precursor is not sufficient, and the three-dimensional object precursor cannot be produced. Therefore, fatty acid with a high acid value is not suitable for the binder jetting method. It is necessary to use a component that can provide sufficient strength even by itself, such as styrene maleic acid resin with an acid value of 120 mgKOH / g or more.

[0199] Examples of aspects of the present invention include the following. <1> a powder layer forming step of forming a powder layer containing a powder containing metal particles; a modeling liquid application step of applying a modeling liquid to the powder layer, the modeling liquid containing an organic solvent and at least one high acid value compound selected from the group consisting of a rosin compound, a styrene compound, and an acrylic compound, the high acid value compound having an acid value of 120 mgKOH / g or more; The present invention relates to a method for producing a three-dimensional object, comprising the steps of: <2> The high acid value compound is at least one selected from the group consisting of acid-modified rosin, polymerized rosin, hydrogenated rosin, rosin-modified maleic acid resin, formylated rosin, fumarated rosin, rosin-modified alkyd resin, acrylated rosin resin, styrene-acrylic resin, styrene-maleic acid resin, and acrylic resin. <1> 2. A method for producing a three-dimensional object according to claim 1 . <3> The molding liquid contains the rosin compound, The composition further contains a resin having a structural unit represented by the following structural formula (1): <1> or <2> 10. A method for producing a three-dimensional object according to claim 9, [ka] <4> The metal particles include at least one selected from the group consisting of particles made of a pure metal and particles made of an alloy. <1> from <3> 10. A method for producing a three-dimensional object according to claim 9, <5> The metal particles contain aluminum. <1> from <4> 10. A method for producing a three-dimensional object according to claim 9, <6> The metal particles further contain at least one selected from the group consisting of silicon and magnesium. <5> 2. A method for producing a three-dimensional object according to claim 1 . <7> A heating step of heating the powder layer to which the modeling liquid has been applied, The heating temperature in the heating step is equal to or lower than the boiling point of the organic solvent at 760 mmHg. <1> from <6> 10. A method for producing a three-dimensional object according to claim 9, <8> A degreasing process for degreasing the powder layer to which the modeling liquid has been applied, The degreasing step includes increasing the temperature from a temperature equal to or lower than the boiling point of the organic solvent at 760 mmHg to a temperature equal to or higher than the decomposition temperature of the organic matter contained in the powder layer. <7> 2. A method for producing a three-dimensional object according to claim 1 . <9> The degreasing step is performed at a temperature of 200° C. or higher and 570° C. or lower. <8> 2. A method for producing a three-dimensional object according to claim 1 . <10> The sintering step includes sintering the degreased powder layer. <9> 2. A method for producing a three-dimensional object according to claim 1 . <11> A modeling liquid for producing a three-dimensional object, which is applied to a powder layer containing a powder containing metal particles, The present invention relates to a modeling liquid for producing three-dimensional objects, the modeling liquid comprising: a high acid value compound having an acid value of 120 mgKOH / g or more, the high acid value compound being at least one selected from the group consisting of rosin compounds, styrene compounds, and acrylic compounds; and an organic solvent. <12> The viscosity of the modeling liquid for producing a three-dimensional object is 5 mPa·s or more and 50 mPa·s or less at 25°C. <11> 1. A modeling liquid for producing a three-dimensional object according to claim 1. <13> The surface tension of the modeling liquid for producing a three-dimensional object is 40 mN / m or less at 25° C. <11> or <12> 1. A modeling liquid for producing a three-dimensional object according to claim 1. <14> The glass transition temperature of the organic component in the modeling liquid for producing a three-dimensional object is 45° C. or higher. <11> from <13> 10. The molding liquid for producing a three-dimensional object according to claim 9, <15> The viscosity of the organic solvent is 5 mPa·s or more and 50 mPa·s or less at 25° C. <11> from <14> 10. The molding liquid for producing a three-dimensional object according to claim 9, <16> The boiling point of the organic solvent at 760 mmHg is 150° C. or higher. <11> from <15> 10. The molding liquid for producing a three-dimensional object according to claim 9,

[0200] The above <1> from <10> The method for producing a three-dimensional object according to any one of the preceding claims and <11> from <16> The molding liquid for producing a three-dimensional object according to any one of the above items can solve the above-mentioned problems in the conventional art and achieve the object of the present invention. [Explanation of symbols]

[0201] 1...Powder layer modeling section 5…Modeling liquid application section 10...Modeling liquid 11...Powder tank 12...Flat area 13...Powder removal section 16...Stacked unit 20…powder 21…Supply tank 22…Building tank 23…Supply stage 24…Modeling stage 25…Surplus powder tank 30…Building layer 31...Powder layer 51…Carriage 52...Head Δt1…Spacing (layer pitch) 100...modeling equipment 200…Heating device 300…Excess powder removal device 400…Sintering equipment 500…Modeling system [Prior art documents] [Patent documents]

[0202] [Patent Document 1] Patent No. 6262404

Claims

1. a powder layer forming step of forming a powder layer containing a powder containing metal particles; a modeling liquid application step of applying a modeling liquid to the powder layer, the modeling liquid containing an organic solvent and at least one high acid value compound selected from the group consisting of a rosin compound, a styrene compound, and an acrylic compound, the high acid value compound having an acid value of 120 mgKOH / g or more; A method for producing a three-dimensional object, comprising:

2. 2. The method for producing a three-dimensional object according to claim 1, wherein the high acid value compound is at least one selected from the group consisting of acid-modified rosin, polymerized rosin, hydrogenated rosin, rosin-modified maleic acid resin, formylated rosin, fumarated rosin, rosin-modified alkyd resin, acrylated rosin resin, styrene-acrylic resin, styrene-maleic acid resin, and acrylic resin.

3. The molding liquid contains the rosin compound, The method for producing a three-dimensional object according to claim 1 , further comprising a resin having a structural unit represented by the following structural formula (1): 【Chemistry 1】

4. The method for producing a three-dimensional object according to claim 1 , wherein the metal particles include at least one type selected from the group consisting of particles made of a pure metal and particles made of an alloy.

5. The method for manufacturing a three-dimensional object according to claim 1 , wherein the metal particles contain aluminum.

6. The method for producing a three-dimensional object according to claim 5 , wherein the metal particles further contain at least one type selected from the group consisting of silicon and magnesium.

7. A heating step of heating the powder layer to which the modeling liquid has been applied, The method for manufacturing a three-dimensional object according to claim 1 , wherein the heating temperature in the heating step is equal to or lower than the boiling point of the organic solvent at 760 mmHg.

8. A degreasing process for degreasing the powder layer to which the modeling liquid has been applied, 8. The method for manufacturing a three-dimensional object according to claim 7, wherein the degreasing step includes increasing a temperature from a temperature equal to or lower than a boiling point of the organic solvent at 760 mmHg to a temperature equal to or higher than a decomposition temperature of the organic matter contained in the powder layer.

9. The method for manufacturing a three-dimensional object according to claim 8 , wherein the degreasing step is performed at a temperature of 200° C. or higher and 570° C. or lower.

10. The method for manufacturing a three-dimensional object according to claim 9 , further comprising a sintering step of sintering the degreased powder layer.

11. A modeling liquid for producing a three-dimensional object, which is applied to a powder layer containing a powder containing metal particles, A modeling liquid for producing a three-dimensional object, comprising: a high acid value compound having an acid value of 120 mgKOH / g or more, the high acid value being at least one selected from the group consisting of rosin compounds, styrene compounds, and acrylic compounds; and an organic solvent.

12. The molding liquid for producing a three-dimensional object according to claim 11, wherein the viscosity of the molding liquid for producing a three-dimensional object at 25°C is 5 mPa·s or more and 50 mPa·s or less.

13. The molding liquid for producing a three-dimensional object according to claim 11, wherein a surface tension of the molding liquid for producing a three-dimensional object is 40 mN / m or less at 25°C.

14. The molding liquid for producing a three-dimensional object according to claim 11, wherein the high acid value compound has a glass transition temperature of 45° C. or higher.

15. The molding liquid for producing a three-dimensional object according to claim 11, wherein the viscosity of the organic solvent is 5 mPa·s or more and 50 mPa·s or less at 25° C.

16. The molding liquid for producing a three-dimensional object according to claim 11, wherein the organic solvent has a boiling point of 150° C. or higher at 760 mmHg.

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