Cleaning solution for removing excess powder, method for manufacturing three-dimensional molded objects, and set of molding solution and cleaning solution.

Abstract

To provide a cleaning liquid for removing surplus powder allowed to remove a surplus powder while maintaining a shape of a solidified object.SOLUTION: A cleaning liquid for removing surplus powder, for use in removing a surplus powder of a solidified object molded using a molding powder, contains a hydrocarbon solvent having an octanol / water partition coefficient (logPow value) of equal to or greater than 4.5.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a cleaning liquid for removing surplus powder, a method for manufacturing a three-dimensional object, and a set of a shaping liquid and a cleaning liquid.

Background Art

[0002] Recently, the need to produce complex and fine-shaped objects made of metals and the like has been increasing. As a technology to meet this need, from the viewpoint of particularly high productivity, there is a method of sintering and densifying a sintered precursor formed by a binder jetting method by powder metallurgy.

[0003] As a method for manufacturing a shaped object such as a green body by a binder jetting method, for example, a crosslinking agent is ejected onto a powder coated with a resin on a base material such as metal, glass, or ceramics, and after dissolving the coated resin, the resin is crosslinked with the crosslinking agent to produce a highly strong shaped object in which solidified products are laminated (see, for example, Patent Document 1).

Summary of the Invention

Problems to be Solved by the Invention

[0004] An object of the present invention is to provide a cleaning liquid for removing surplus powder that can remove surplus powder while maintaining the shape of the solidified product.

Means for Solving the Problems

[0005] The cleaning liquid for removing surplus powder of the present invention as a means for solving the above problems is a cleaning liquid for removing surplus powder used to remove surplus powder of a solidified product formed using shaping powder, and contains a hydrocarbon solvent having an octanol / water partition coefficient (logP ow value) of 4.5 or more.

Effects of the Invention

[0006] According to the present invention, it is possible to provide a cleaning liquid for removing surplus powder that can remove surplus powder while maintaining the shape of the solidified product. [Brief explanation of the drawing]

[0007] [Figure 1A] Figure 1A is a schematic diagram showing an example of the operation of a three-dimensional object manufacturing apparatus. [Figure 1B] Figure 1B is a schematic diagram showing another example of the operation of a three-dimensional object manufacturing apparatus. [Figure 1C] Figure 1C is a schematic diagram showing another example of the operation of a three-dimensional object manufacturing apparatus. [Figure 1D] Figure 1D is a schematic diagram showing another example of the operation of a three-dimensional object manufacturing apparatus. [Figure 1E] Figure 1E is a schematic diagram showing another example of the operation of a three-dimensional object manufacturing apparatus. [Figure 2A] Figure 2A is a photograph of the unsintered body immediately after immersion in the cleaning solution in Example 1. [Figure 2B] Figure 2B is a photograph of the unsintered body in Example 1 after being sonicated in an ultrasonic bath and immersed in a cleaning solution for 30 minutes. [Figure 3A] Figure 3A is a photograph of the unsintered body immediately after immersion in the cleaning solution in Example 2. [Figure 3B] Figure 3B is a photograph of the unsintered body in Example 2 after being sonicated in an ultrasonic bath and immersed in a cleaning solution for 30 minutes. [Figure 4A] Figure 4A is a photograph of the unsintered body immediately after immersion in the cleaning solution in Example 3. [Figure 4B] Figure 4B is a photograph of the unsintered body in Example 3 after being sonicated in an ultrasonic bath and immersed in a cleaning solution for 30 minutes. [Figure 5A] Figure 5A is a photograph of the unsintered body immediately after immersion in the cleaning solution in Example 4. [Figure 5B] Figure 5B is a photograph of the unsintered body in Example 4 after being sonicated in an ultrasonic bath and immersed in a cleaning solution for 30 minutes. [Figure 6A] Figure 6A is a photograph of the unsintered body in Comparative Example 1 immediately after immersion in the cleaning solution. [Figure 6B] Figure 6B is a photograph of the unsintered body in Comparative Example 1 after being sonicated in an ultrasonic bath and immersed in a cleaning solution for 30 minutes. [Figure 7A] Figure 7A is a photograph of the unsintered body immediately after immersion in the cleaning solution in Comparative Example 2. [Figure 7B] Figure 7B is a photograph of the unsintered body in Comparative Example 2 after being sonicated in an ultrasonic bath and immersed in a cleaning solution for 30 minutes. [Figure 8A] Figure 8A is a photograph of the unsintered body immediately after immersion in the cleaning solution in Comparative Example 3. [Figure 8B] Figure 8B is a photograph of the unsintered body in Comparative Example 3 after being sonicated in an ultrasonic bath and immersed in a cleaning solution for 30 minutes. [Figure 9A] Figure 9A is a photograph of the unsintered body immediately after immersion in the cleaning solution in Example 5. [Figure 9B] Figure 9B is a photograph of the unsintered body in Example 5 after being immersed in a cleaning solution for 30 minutes while undergoing ultrasonic treatment in an ultrasonic bath. [Figure 10A] Figure 10A is a photograph of the unsintered body immediately after immersion in the cleaning solution in Example 6. [Figure 10B] Figure 10B is a photograph of the unsintered body in Example 6 after being sonicated in an ultrasonic bath and immersed in a cleaning solution for 30 minutes. [Figure 11A] Figure 11A is a photograph of the unsintered body immediately after immersion in the cleaning solution in Comparative Example 4. [Figure 11B] Figure 11B is a photograph of the unsintered body in Comparative Example 4 after being sonicated in an ultrasonic bath and immersed in a cleaning solution for 30 minutes. [Figure 12A] Figure 12A is a photograph of the unsintered body immediately after immersion in the cleaning solution in Comparative Example 5. [Figure 12B] Figure 12B is a photograph of the unsintered body in Comparative Example 5 after being sonicated in an ultrasonic bath and immersed in a cleaning solution for 30 minutes. [Figure 13A]Figure 13A is a photograph of the unsintered body immediately after immersion in the cleaning solution in Example 7. [Figure 13B] Figure 13B is a photograph of the unsintered body in Example 7 after being immersed in a cleaning solution for 30 minutes while undergoing ultrasonic treatment in an ultrasonic bath. [Figure 14A] Figure 14A is a photograph of the unsintered body immediately after immersion in the cleaning solution in Example 8. [Figure 14B] Figure 14B is a photograph of the unsintered body after being immersed in a cleaning solution for 30 minutes while undergoing ultrasonic treatment in an ultrasonic bath in Example 8. [Figure 15A] Figure 15A is a photograph of the unsintered body immediately after immersion in the cleaning solution in Comparative Example 6. [Figure 15B] Figure 15B is a photograph of the unsintered body in Comparative Example 6 after being sonicated in an ultrasonic bath and immersed in a cleaning solution for 30 minutes. [Modes for carrying out the invention]

[0008] (Cleaning solution for removing excess powder) The present invention is a cleaning solution for removing excess powder used to remove excess powder from solidified products formed using molding powder, Octanol / Water partition coefficient (logP) ow It contains a hydrocarbon solvent with a value of 4.5 or higher, and further contains other components as needed.

[0009] In this disclosure, "powder" may also be referred to as "powder material" or "powder." In this disclosure, the term "molding liquid" may also be referred to as "curing liquid" or "reaction liquid." In this disclosure, "formed object" means an assembly of one or more layers (laminate) formed by applying a molding liquid to powder. In this disclosure, "solidified material" refers to a material obtained by solidifying a "molded object," and may also be referred to as a "cured material." Furthermore, a solidified material obtained by solidifying a stacked, three-dimensional molded object may also be referred to as an "unsintered body," "green body," or "molded body." A "solidified material (such as an unsintered body)" that has been heat-treated and degreased is sometimes called a "degreased body." Both "unsintered bodies" and "degreased bodies" are sometimes simply referred to as "sintering precursors." A sintered "degreased body" is sometimes referred to as a "sintered body" or "three-dimensional object." In this invention, "excess powder" refers to powder adhering to the surface of an unsintered body. Furthermore, "powder" refers to powder including molding powder. Furthermore, "formed object," "solidified object," "degreased object," and "sintered object" each include both a single-layer planar structure and a three-dimensional structure (laminated object) consisting of multiple layers.

[0010] Conventional techniques involved creating crosslinked and non-crosslinked regions within the resin of the solidified material (unsintered body) to control dissolution in the cleaning solution. However, this approach had problems, such as insufficient reaction in the crosslinked regions, which could result in softened molded objects. Furthermore, conventional technologies use resins that are easily soluble in organic solvents as binder resins (for example, polyvinyl acetate-based resins, polyvinyl butyral-based resins, etc.), and when excess powder is removed by immersion in an organic solvent for washing, the resin dissolves, resulting in a problem where the shape of the unsintered body cannot be maintained.

[0011] After diligent research by the inventors, we determined that the octanol / water partition coefficient (logP ow The inventors have found that a hydrocarbon solvent with an octanol / water partition coefficient (logP) of 4.5 or higher can be used as a cleaning solution for removing excess powder from solidified material (unsintered body, green body) after the application of binder resin (molding liquid). In other words, the inventors have found that a hydrocarbon solvent with an octanol / water partition coefficient (logP) of 4.5 or higher can be used as a cleaning solution for removing excess powder from solidified material (unsintered body, green body) after the application of binder resin (molding liquid). ow We found that hydrocarbon solvents with a value of 4.5 or higher can remove only excess powder without dissolving the binder resin (molding liquid) in the solidified product after application and solidification. Furthermore, the inventors have identified the "octanol / water partition coefficient (logP owIt has been found that a hydrocarbon solvent with an octanol / water partition coefficient (logPow value) of 4.5 or more can be used without problems for the metal powder used in stereolithography. For example, the case of using partially saponified polyvinyl acetate as the resin contained in the shaping liquid will be described. Partially saponified polyvinyl acetate contains a large amount of hydrophobic vinyl acetate groups in the polymer, and depending on the grade, it contains 90 mol% or more in the polymer. Resins containing vinyl acetate groups at a high concentration dissolve in hydrocarbon solvents such as benzene and paraffin oil. Since the binder resin contained in the solidified product is at most around 2% by mass and is small, the solidified product collapses just by the resin being slightly dissolved or swollen. Therefore, the polarity of the cleaning liquid becomes very important. [[ID=३]] The inventors have found that by reducing the polarity of the solvent to the non-polar side as much as possible, hydrophobic resins do not dissolve. From this, the inventors have found that if the "octanol / water partition coefficient logPow value", which is an index of polarity (hydrophilicity, hydrophobicity), is 4.5 or more, even when an organic solvent is used as the cleaning liquid, even if a hydrophobic resin such as polyvinyl acetate is used as the binder resin, the resin does not dissolve and the shape of the green compact can be maintained.

[0012] <Hydrocarbon solvent> The hydrocarbon solvent has an octanol / water partition coefficient (logP ow value) of 4.5 or more, preferably 5.0 or more, and more preferably 5.0 or more and 8.0 or less. The octanol / water partition coefficient (logP ow value) of 4.5 or more, there is no particular limitation on the hydrocarbon solvent, and it can be appropriately selected according to the purpose. Examples of the hydrocarbon solvent having an octanol / water partition coefficient (logP ow value) of 4.5 or more include, for example, decane (logP ow value: 5.0), dodecane (logP ow value: 6.1), tetradecane (logP ow value: 7.2), p-menthane (logP ow value: 5.5), undecane (logPow Value: 5.6), Tridecane (logP ow Value: 6.6), Pentadecane (logP ow Examples include the value 7.7. Note that the octanol / water partition coefficient (logP ow The value represents the ratio of the concentration of a compound dissolved in the octanol phase to the concentration of a compound dissolved in water in a two-phase system of octanol and water. The intrinsic octanol / water partition coefficient (logP) of the hydrocarbon solvent. ow The value can be extracted by referring to a chemical database (PubChem, https: / / pubchem.ncbi.nlm.nih.gov / ). In addition to chemical databases, the octanol / water partition coefficient (logP) can also be obtained. ow The value may refer to the value specified in the Safety Data Sheet (SDS) of the hydrocarbon solvent used.

[0013] Furthermore, it is preferable that the hydrocarbon solvent is a hydrocarbon solvent that does not contain double bonds in its molecule. If the hydrocarbon solvent is a hydrocarbon solvent that does not contain double bonds in its molecule, the octanol / water partition coefficient (logP ow When the value becomes too low, the binder resin dissolves during the removal of excess powder from the solidified material (unsintered body), which can improve the effect of suppressing the collapse of the solidified material (unsintered body).

[0014] Furthermore, the hydrocarbon solvent is preferably a hydrocarbon having 7 to 15 carbon atoms, and more preferably 10 to 14 carbon atoms. When the hydrocarbon solvent is a hydrocarbon having 7 or more carbon atoms, the octanol / water partition coefficient (logP ow As the value increases, the hydrophobicity of the hydrocarbon solvent increases, which improves the effect of preventing the dissolution and swelling of the binder resin that binds the metal particles when removing excess powder from the solidified product (unsintered body), and suppressing the collapse of the solidified product (unsintered body). Furthermore, if the hydrocarbon has 15 carbon atoms or less, the boiling point rises with increasing carbon atoms, which improves the effect of suppressing the need for a long drying time of the cleaning solution.

[0015] The content of the hydrocarbon solvent is not particularly limited as long as it is sufficient to achieve the effects of the present invention, and can be appropriately selected depending on the purpose. Preferably, the hydrocarbon solvent content is such that it substantially does not contain any components other than the hydrocarbon solvent. "Substantially free of components other than the hydrocarbon solvent" does not exclude components other than the hydrocarbon solvent, as long as it is sufficient to achieve the effects of the present invention. The content of the hydrocarbon solvent is preferably 100% by mass or less relative to the total amount of the cleaning solution for removing excess powder.

[0016] <Other ingredients> The other components mentioned above are not particularly limited and can be selected as appropriate depending on the purpose.

[0017] The cleaning solution for removing excess powder of the present invention is used to remove excess powder from solidified material obtained by heating the molded object. The following describes the molding powders used to produce solidified products to which the cleaning solution for removing excess powder of the present invention is applied.

[0018] [Powder for modeling] The aforementioned molding powder is not particularly limited as long as it is a powder that has been conventionally used in binder jetting methods, and can be appropriately selected according to the purpose. For example, powders containing metal particles can be used.

[0019] <Metal particles> The aforementioned metal particles are particles that contain metal as a constituent material and are used in the manufacture of three-dimensional objects. The constituent materials of the metal particles are not particularly limited as long as they contain metal, and may also contain materials other than metal, but it is preferable that the main material is metal. "The main material is metal" means that the mass of metal contained in the metal particles is 50.0% by mass or more of the total mass of the metal particles, preferably 60.0% by mass or more, more preferably 70.0% by mass or more, even more preferably 80.0% by mass or more, and particularly preferably 90.0% by mass or more.

[0020] Examples of metals that make up metal particles include magnesium (Mg), aluminum (Al), titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), yttrium (Y), zirconium (Zr), niobium (Nb), molybdenum (Mo), lead (Pd), silver (Ag), indium (In), tin (Sn), tantalum (Ta), tungsten (W), neodymium (Nd), and alloys of these metals. Among these, stainless steel (SUS), iron (Fe), copper (Cu), silver (Ag), titanium (Ti), aluminum (Al), and alloys of these metals are preferably used. Examples of the aforementioned aluminum alloy include AlSi 10 Mg, AlSi 12 AlSi7Mg 0.6 , AlSi3Mg, AlSi9Cu3, Scalmalloy, ADC 12 Examples include AlSi3. These can be used individually or in combination of two or more.

[0021] The aforementioned metal particles can be manufactured using conventionally known methods. Methods for producing the aforementioned metal particles include, for example, a pulverization method that subdivides a solid by applying compression, impact, friction, etc.; an atomization method that obtains a rapidly cooled powder by spraying molten metal; a precipitation method that precipitates components dissolved in a liquid; and a gas-phase reaction method that vaporizes and crystallizes the particles. Among these, the atomization method is preferred because it yields spherical particles with little variation in particle size. Examples of atomization methods include water atomization, gas atomization, centrifugal atomization, and plasma atomization, all of which are suitably used.

[0022] The aforementioned metal particles may be commercially available products. Examples of the aforementioned commercially available products include 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), and AlSi 10 Mg (manufactured by Toyo Aluminum Co., Ltd., Si 10 Examples include MgBB, SiO2 (manufactured by Tokuyama Corporation, product name: Excelica SE-15K), AlO2 (manufactured by Daimyo Chemical Industry Co., Ltd., product name: Tymicron TM-5D), and ZrO2 (manufactured by Tosoh Corporation, product name: TZ-B53).

[0023] There are no particular restrictions on the volume-average particle size of the metal particles, and they can be appropriately selected according to the purpose. For example, a size of 2 μm to 100 μm is preferred, and a size of 8 μm to 50 μm is more preferred. When the volume-average particle size of the metal particles is 2 μm or more, aggregation of the metal particles is suppressed, which can prevent a decrease in the manufacturing efficiency of the molded product and a decrease in the handling of the metal particles. Furthermore, when the average particle size of the metal particles is 100 μm or less, a decrease in the contact points between metal particles and an increase in voids can be suppressed, which can prevent a decrease in the strength of the molded product. There are no particular restrictions on the particle size distribution of the metal particles, and they can be appropriately selected according to the purpose, however, a sharper particle size distribution is preferable. The volume-average particle size and particle size distribution of the metal particles can be measured using a known particle size measuring device, such as the Microtrac MT3000II series particle size distribution measuring device (manufactured by Microtrac Bell).

[0024] While a method for manufacturing molded objects using metal particles having a metal substrate and a coating resin covering the substrate, and applying a liquid to the metal particles to allow the coating resin to exhibit its binder function, in this disclosure, the molding liquid contains a resin having a binder function. Therefore, the metal particles do not need to be coated with resin. By using metal particles whose surfaces are not coated with the aforementioned resin, it is possible to suppress the formation of unintended solidified material, for example, in areas of powder that are not coated with liquid (in other words, non-molding areas), by preventing the coating resin from binding the metal particles together during the solidification process. Furthermore, the metal particles are not limited to the resin mentioned above; their surfaces do not need to be coated with organic compounds such as surface treatment agents. The surface treatment agent is not particularly limited and can be appropriately selected depending on the purpose. Examples include silane coupling agents.

[0025] Here, "surface not coated with resin" means, for example, that the ratio of the surface area of ​​the resin or organic compound to the surface area of ​​the metal particles (surface coverage rate) is less than 15%, and may be 0%. The surface coverage ratio is determined, for example, by taking a photograph of the metal particles and measuring the ratio (%) of the area covered by the resin or organic compound to the total surface area of ​​the metal particles within the range captured in the two-dimensional photograph. For determining the area covered by the resin or organic compound, techniques such as elemental mapping using energy-dispersive X-ray spectroscopy (SEM-EDS) can be used.

[0026] <<Powder containing metal particles>> The above-mentioned metal particles are used as a powder, which is an aggregate containing multiple metal particles, and a molded object is manufactured by applying a molding fluid to this powder layer. The aforementioned powder may contain, in addition to metal particles, other components as needed. Other components include, for example, fillers, leveling agents, sintering aids, and polymer resin particles. The filler is an effective material for adhering to the surface of metal particles or filling the voids between metal particles. By including the filler, for example, the fluidity of the powder can be improved, and the number of contact points between metal particles can be increased and voids can be reduced, thereby improving the strength and dimensional accuracy of the solidified product (unsintered body). The leveling agent is an effective material for controlling the wettability on the surface of the powder layer. By using the leveling agent, for example, the penetration of the molding fluid into the powder layer can be increased, and the strength of the solidified product (unsintered body) can be increased. The aforementioned sintering aid is an effective material for increasing sintering efficiency when sintering solidified material (unsintered body). By using the sintering aid, for example, the strength of the molded object can be improved, the sintering temperature can be lowered, and the sintering time can be shortened. The aforementioned polymer resin particles are an effective material for adhering to the surface of metal particles and are also referred to as organic additives. The average particle size of the polymer resin particles is not particularly limited, but is preferably 0.1 μm or more and 10 μm or less, and more preferably 0.1 μm or more and 1 μm or more.

[0027] The angle of repose of the powder is preferably 60° or less, more preferably 50° or less, and even more preferably 40° or less. When the angle of repose of the powder is 60° or less, the powder can be efficiently and stably placed at a desired location on the support. The angle of repose can be measured using, for example, a powder properties measuring device (such as a powder tester PT-N, manufactured by Hosokawa Micron Corporation).

[0028] (Method for manufacturing three-dimensional objects and apparatus for manufacturing three-dimensional objects) The method for manufacturing a three-dimensional object according to the present invention is: A powder layer formation step in which a powder layer containing molding powder is formed, A molding liquid application step involves applying a molding liquid containing resin to the powder layer to form a molded object, A solidification step to solidify the molded object to obtain a solidified product, The molding powder adhering to the solidified material is subjected to an octanol / water partition coefficient (logP owA process to remove excess powder using a washing solution containing a hydrocarbon solvent with a value of 4.5 or higher, This includes, and further, as necessary, lamination, sintering, and other processes. The manufacturing apparatus for a three-dimensional object according to the present invention is: A powder layer forming means for forming a powder layer containing molding powder, A molding liquid application means for applying a molding liquid containing resin to the powder layer to form a molded object, A solidification means for solidifying the molded object to obtain a solidified product, Remove the molding powder adhering to the solidified material, using an octanol / water partition coefficient (logP ow A cleaning solution containing a hydrocarbon solvent having a value of 4.5 or higher, and a cleaning solution container containing the cleaning solution. A means for removing excess powder adhering to the solidified material with the cleaning solution, It has, and furthermore, other means as needed.

[0029] As a result of diligent research by the present inventors, the octanol / water partition coefficient (logP) of the resin contained in the molding liquid and the cleaning liquid is determined to be the same. ow The inventors found that if the value is 4.5 or higher, excess powder from the unsintered body (green body) after the application of binder resin (molding liquid) can be removed using a liquid. In other words, the inventors found that if the octanol / water partition coefficient (logP) of the hydrocarbon solvent contained in the cleaning liquid is 4.5 or higher, the excess powder from the unsintered body (green body) can be removed using a liquid. ow The value is logP ow We found that when the value is 4.5 or higher, it is possible to remove only the excess powder from the unsintered body after the binder resin (molding fluid) has been applied, without dissolving the binder resin. Furthermore, the present inventors have determined the octanol / water partition coefficient (logP) of the hydrocarbon solvent contained in the washing solution. ow We found that if the value is 4.5 or higher, it can be used without problems as a metal powder for three-dimensional modeling.

[0030] <Powder layer formation process and means for forming a powder layer> The aforementioned powder layer formation step is a step of forming a powder layer containing molding powder. The aforementioned powder layer forming means is a means for forming a powder layer containing molding powder. The molding powder is the same as the molding powder described in the cleaning solution for removing excess powder of the present invention. The aforementioned powder layer is formed on the support (on the molding stage). There are no particular limitations on the method for forming a thin layer of powder by arranging the powder on a support (powder layer forming means), and it can be appropriately selected according to the purpose. Examples include a method using a known counter rotation mechanism (counter roller) used in the selective laser sintering method described in Japanese Patent Publication No. 3607300, a method of spreading the powder using a brush, roller, blade, or other component, a method of pressing and spreading the surface of the powder with a pressing component, and a method using a known additive manufacturing apparatus.

[0031] When forming a powder layer using the aforementioned counter rotation mechanism (counter roller), brush, blade, pressing member, and other powder layer forming means, it can be carried out, for example, in the following manner. Specifically, powder is placed on a support that is positioned to slide up and down along the inner wall of an outer frame (sometimes called a "mold," "hollow cylinder," or "tubular structure") using a counter-rotating mechanism (counter roller), brush, roller, blade, or pressing member. When a support that can move up and down within the outer frame is used, the support is positioned slightly below the upper opening of the outer frame (in other words, positioned below by the thickness of one layer of powder), and the powder is placed on the support. In this way, a thin layer of powder can be placed on the support.

[0032] There are no particular restrictions on the thickness of the powder layer, and it can be appropriately selected according to the purpose. For example, the average thickness per layer is preferably 30 μm or more and 500 μm or less, and more preferably 60 μm or more and 300 μm or less. If the average thickness 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 processes such as the sintering process can be suppressed. If the average thickness is 500 μm or less, the dimensional accuracy of the molded object derived from the molded object formed by applying the molding liquid to the powder is improved. Furthermore, there are no particular restrictions on the average thickness, and it can be measured according to known methods.

[0033] The powder supplied by the powder layer forming means may be contained in a powder containment section. The powder containment section is a container or other component that contains the powder, and examples include storage tanks, bags, cartridges, and tanks.

[0034] <Modeling fluid application process and modeling fluid application means> The molding fluid application step is a step of applying a molding fluid containing resin to the powder layer to form a molded object. The molding fluid application means is a means of applying a molding fluid containing resin to the powder layer to form a molded object.

[0035] <<Modeling liquid>> The aforementioned molding fluid is a liquid composition used in the manufacture of molded objects and applied to a powder layer containing metal particles. The molding fluid contains a resin and, if necessary, also contains organic solvents, additives, and other components.

[0036] <<<Resin>>> The aforementioned resin is not particularly limited as long as it can function as a binder resin that is applied to powder to bond individual particles in the manufacturing of three-dimensional objects, and can be appropriately selected according to the purpose. The resin is such that it is soluble in solvent A, and the octanol / water partition coefficient of solvent A is logP owThe value is preferably between -1.8 and 3.4. Note that solvent A is a different solvent from the hydrocarbon solvent. Octanol / Water partition coefficient (logP) ow The solvent A, whose value is between -1.8 and 3.4, is, for example, glycerin (logP ow Value: -1.8), γ-butyrolactone (logP ow Value: -0.6), Water (logP ow Value: -0.5), 1-butanol (logP ow Value: 0.9), 1-hexanol (logP ow Value: 2.0), dipentene (D-limonene) (logP ow Examples of values ​​include 3.4. Note that the octanol / water partition coefficient (logP ow The value represents the ratio of the concentration of a compound dissolved in the octanol phase to the concentration of a compound dissolved in water in a two-phase system of octanol and water. The octanol / water partition coefficient (logP) ow The value can be extracted by referring to a chemical database (PubChem, https: / / pubchem.ncbi.nlm.nih.gov / ). In addition to chemical databases, the octanol / water partition coefficient (logP) can also be obtained. ow The value may refer to the value listed in the Safety Data Sheet (SDS) of the solvent used. If the resin is a resin that can be dissolved in the solvent A, then when using the cleaning solution, the effect of removing only excess powder without dissolving the binder resin (resin contained in the molding liquid) in the unsintered body after the binder resin has been applied can be improved. Here, we have the conditions that "the resin is soluble in solvent A" and "the octanol / water partition coefficient of solvent A (logP ow An example of the relationship between the value being "between -1.8 and 3.4" and the following will be explained with reference to Table 1 below.

[0037] [Table 1]

[0038] As shown in Table 1, the octanol / water partition coefficient (logP ow γ-butyrolactone with a value of -0.6 can dissolve all of the hydrophobic resins JMR-10LL (polyvinyl acetate) and Esrec BL-10 (polyvinyl butyral), as well as the water-soluble resin PVP (polyvinylpyrrolidone). On the other hand, for example, the octanol / water partition coefficient (logP ow Water with a value of "-0.5" can dissolve the water-soluble resin "PVP (polyvinylpyrrolidone)", but it cannot dissolve the hydrophobic resins "JMR-10LL (polyvinyl acetate)" and "Eslec BL-10 (polyvinyl butyral)". Also, the octanol / water partition coefficient (logP) ow Dipentene (D-limonene), which has a value of "3.4", cannot dissolve PVP (polyvinylpyrrolidone). Thus, in the present invention, "the resin is soluble in solvent A" means "the octanol / water partition coefficient (logP ow It is not necessary for the substance to be soluble in all solvents whose value falls between -1.8 and 3.4; it simply means that there are substances that can be soluble in solvents within this range.

[0039] Furthermore, "soluble in the aforementioned solvent" means that 1 g or more can be dissolved in 100 g of solvent at 25°C.

[0040] Examples of the aforementioned resin include polymers having at least one monomer selected from vinyl acetate, allyl alcohol, vinyl alcohol, vinylpyrrolidone, urethane, and meth(acrylate) as structural units. Furthermore, examples of the resin include resins that can be dissolved or dispersed in other organic solvents, or resins that can be dissolved or dispersed in aqueous solvents such as polyhydric alcohols containing water.

[0041] The aforementioned resin includes, for example, a resin having at least one of the structural units represented by the following structural formula (1) and structural units represented by the following structural formula (2). In this disclosure, "structural unit" refers to a partial structure in a resin derived from one or more polymerizable compounds. [ka] [ka]

[0042] -A resin having structural units represented by structural formula (1)- The resin having the structural unit represented by the structural formula (1) is arranged in the powder layer when the molding liquid is applied to the powder layer containing metal particles, and through an appropriate solidification process (heat treatment) corresponding to the softening point of the resin, it functions as a binder that binds the metal particles together in the region to which the molding liquid has been applied, thereby forming a molded object and pre-sintered solidified materials such as unsintered bodies derived from the molded object. These pre-sintered solidified materials are formed from a resin having structural units represented by structural formula (1), which imparts flexibility, thus improving flexural strength.

[0043] Furthermore, the resin having the structural unit represented by the structural formula (1) exhibits excellent thermal decomposition properties, allowing it to be appropriately removed in the degreasing process, thereby improving the density of the sintered body produced through the subsequent sintering process. Therefore, as described in this disclosure, when metal particles that are intended for sintering or are preferably sintered are used as the material for forming the molded object, the effects obtained become more pronounced. Specifically, the resin having the structural unit represented by structural formula (1) is preferably thermally decomposed by 95% by mass or more when heated from 30°C to 550°C, and more preferably by 97% by mass or more. In this disclosure, "thermal decomposition of the resin" means that random decomposition of the main chain or depolymerization at the molecular chain ends occurs, and the resin is removed by vaporization, oxidative decomposition, combustion, etc. Furthermore, thermal decomposition is measured using a TG-DTA (Differential Thermal Analysis-Thermogravimetric Analysis) device. Specifically, the temperature is raised from 30°C to 550°C at a rate of 10°C / min in an air or nitrogen atmosphere, and then the temperature is maintained for 2 hours after reaching 550°C, and the weight loss rate before and after the temperature increase is determined.

[0044] Furthermore, the resin having the structural unit represented by structural formula (1) exhibits improved solubility in organic solvents due to the hydrophobicity of the structural unit represented by structural formula (1). Therefore, when the molding fluid contains an organic solvent, the solubility of the resin having the structural unit represented by structural formula (1) improves, and consequently, the viscosity of the molding fluid can be reduced. For example, the molding fluid can be appropriately ejected using an inkjet method. It is preferable that the resin having the structural unit represented by structural formula (1) is soluble in the organic solvent of the molding fluid and insoluble in water.

[0045] The Tg of the resin having the structural unit represented by the structural formula (1) is preferably 0°C or higher, more preferably 10°C or higher, and even more preferably 20°C or higher. Furthermore, the Tg of the resin having the structural unit represented by the structural formula (1) is preferably 100°C or lower, more preferably 90°C or lower, and even more preferably 80°C or lower.

[0046] The softening point of the resin having the structural unit represented by the structural formula (1) is preferably 70°C or higher, more preferably 80°C or higher, and even more preferably 90°C or higher. Furthermore, the softening point of the resin having the structural unit represented by the structural formula (1) is preferably 150°C or lower, more preferably 140°C or lower, and even more preferably 130°C or lower.

[0047] The number-average molecular weight (Mn) of the resin having the structural unit represented by the structural formula (1) is preferably 5,000 to 50,000, and more preferably 10,000 to 30,000. When the number-average molecular weight (Mn) of the resin having the structural unit represented by the structural formula (1) is within the above range, it is possible to achieve both improved strength and molding accuracy of the molded or solidified product, and a decrease in the viscosity of the molding fluid and an increase in the resin concentration in the molding fluid.

[0048] The resin having the structural unit represented by structural formula (1) may be either a resin having structural units other than those represented by structural formula (1) or a resin not having structural units other than those represented by structural formula (1). Examples of structural units other than those represented by structural formula (1) include the structural unit represented by the following structural formula (3) and the structural unit represented by the following structural formula (4). [ka] [ka]

[0049] A resin having structural units represented by structural formula (3) in addition to the structural units represented by structural formula (1) improves the flexural strength of molded objects and solidified materials before sintering, such as unsintered bodies derived from molded objects. Furthermore, the structural unit represented by structural formula (3) is hydrophobic, similar to the structural unit represented by structural formula (1), thereby improving the solubility of the resin in organic solvents. From these viewpoints, in a resin, the total amount of structural units represented by structural formula (1) and structural formula (3) is preferably 60 mol% or more, more preferably 65 mol% or more, even more preferably 70 mol% or more, even more preferably 75 mol% or more, and particularly preferably 80 mol% or more, relative to the total amount of structural units represented by structural formula (1), structural formula (3), and structural formula (4). The same applies when the resin does not contain structural units represented by structural formula (3) or structural formula (4), in which case the above percentages can be calculated by setting the amount of the missing structural units to 0.

[0050] A resin having structural units represented by structural formula (4) in addition to structural units represented by structural formula (1) improves the affinity with metal particles in the powder layer to which the molding liquid is applied due to the hydroxyl groups in the structural units represented by structural formula (4). As a result, the flexural strength of the molded product and the solidified material before sintering, such as the unsintered body derived from the molded product, is further improved, and the density of the solidified material before sintering and the solidified material after sintering is also further improved. From these viewpoints, in the resin, the amount of structural units represented by structural formula (4) is preferably 5 mol% or more, more preferably 15 mol% or more, and even more preferably 25 mol% or more, relative to the total amount of structural units represented by structural formula (1), structural units represented by structural formula (3), and structural units represented by structural formula (4). However, since the structural unit represented by structural formula (4) is hydrophilic, an increase in the proportion of structural units represented by structural formula (4) suppresses the improvement in the solubility of the resin having structural units represented by structural formula (1) when the molding fluid contains an organic solvent, and consequently suppresses the decrease in the viscosity of the molding fluid. From this viewpoint, in the resin, the amount of structural units represented by structural formula (4) is preferably 40 mol% or less, more preferably 35 mol% or less, even more preferably 30 mol% or less, even more preferably 25 mol% or less, and particularly preferably 20 mol% or less, relative to the total amount of structural units represented by structural formula (1), structural units represented by structural formula (3), and structural units represented by structural formula (4). The same applies when the resin does not have structural units represented by structural formula (3), in which case the above proportions can be calculated by setting the amount of the absent structural units to 0.

[0051] Specific examples of resins having structural units represented by structural formula (1) include polyvinyl acetate resin, partially saponified polyvinyl acetate resin, and polyvinyl butyral resin. Among these, polyvinyl acetate resin and a specified partially saponified polyvinyl acetate resin are preferred because they can reduce the viscosity of the molding fluid. Here, the specified partially saponified polyvinyl acetate resin refers to a partially saponified polyvinyl acetate resin in which the amount of structural units represented by structural formula (1) is 75 mol% or more of the total amount of structural units represented by structural formula (1) and structural formula (4), and preferably refers to a partially saponified polyvinyl acetate resin in which the amount is 80 mol% or more. These resins may be used individually, or two or more may be used in combination. Both commercially available and synthetic resins can be used.

[0052] In this disclosure, polyvinyl acetate resin is a resin having structural units represented by structural formula (1) and substantially lacking structural units represented by structural formula (3) and structural formula (4). Partially saponified polyvinyl acetate resin is a resin that has structural units represented by structural formula (1) and structural units represented by structural formula (4), but substantially does not have structural units represented by structural formula (3). Polyvinyl butyral resin is a resin having structural units represented by structural formula (1) and structural units represented by structural formula (3), or a resin having structural units represented by structural formula (1), structural units represented by structural formula (3), and structural units represented by structural formula (4). Partially saponified polyvinyl acetate resin is a resin obtained by partially saponifying polyvinyl acetate resin. Furthermore, in the partially saponified polyvinyl acetate resin in this disclosure, the amount of structural units represented by structural formula (4) is 40 mol% or less, preferably 35 mol% or less, more preferably 30 mol% or less, even more preferably 25 mol% or less, and even more preferably 20 mol% or less, relative to the total amount of structural units represented by structural formula (1) and structural units represented by structural formula (4). In other words, in the partially saponified polyvinyl acetate resin in this disclosure, the degree of saponification is 40 or less, preferably 35 or less, more preferably 30 or less, even more preferably 25 or less, and even more preferably 20 or less.

[0053] The content of the resin having the structural unit represented by structural formula (1) is preferably 5.0% by mass or more, more preferably 7.0% by mass or more, even more preferably 10.0% by mass or more, and particularly preferably 11.0% by mass or more, relative to the mass of the molding fluid. Furthermore, it is preferably 30.0% by mass or less, more preferably 25.0% by mass or less, and even more preferably 20.0% by mass or less. A content of 5.0% by mass or more further improves the flexural strength of the molded object and the solidified material before sintering, such as the unsintered body derived from the molded object. Furthermore, a content of 30.0% by mass or less further reduces the viscosity of the molding fluid, allowing the molding fluid to be appropriately ejected, for example, by an inkjet method. Furthermore, resins in which the total amount of structural units represented by structural formula (1) and structural formula (3) is 95 mol% or more of the total amount of structural units represented by structural formula (1), structural formula (3), and structural formula (4) have improved solubility in organic solvents and reduced viscosity of the molding fluid, so they can also be included in high mass (for example, 15.0% by mass or more or 20.0% by mass or more relative to the mass of the molding fluid). This further improves the flexural strength of the molded object and the solidified material before sintering, such as the unsintered body derived from the molded object.

[0054] The amount (mol%) of each structural unit represented by its structural formula in the resin can be determined, for example, by the polyvinyl alcohol test method described in JIS-K6276-1994.

[0055] -A resin having structural units represented by structural formula (2)- The resin having structural units represented by structural formula (2) is arranged within the powder layer when the molding fluid is applied to the powder layer containing metal particles. Through an appropriate solidification process corresponding to the softening point of the resin, it functions as a binder that binds the metal particles together in the region where the molding fluid is applied, forming a molded object and pre-sintered solidified materials such as unsintered bodies derived from the molded object. These pre-sintered molded objects are formed from a resin having structural units represented by structural formula (2), which has a five-membered ring lactam structure with high affinity for metal. As a result, the metal particles are strongly bonded together, improving flexural strength.

[0056] Furthermore, resins having structural units represented by structural formula (2) exhibit excellent thermal decomposition properties if the temperature rise profile is appropriately controlled, allowing them to be properly removed in the degreasing process, and improving the density of the sintered body produced through the subsequent sintering process. Therefore, as described in this disclosure, when metal particles that are intended for or preferably sintered are used as the material for forming the molded object, the effects obtained become more pronounced. Specifically, the resin having the structural unit represented by structural formula (2) is preferably thermally decomposed by 95% by mass or more when heated from 30°C to 550°C, and more preferably by 97% by mass or more. However, resins having structural units represented by structural formula (2) may form crosslinked structures under certain temperature conditions (e.g., heating conditions of 160°C or higher), which can suppress the effect of high thermal decomposition. Therefore, as in this disclosure, when using metal particles that are intended for or preferably sintered as a material for forming molded objects, it may be preferable to use a resin having structural units represented by structural formula (1) rather than a resin having structural units represented by structural formula (2) from the viewpoint of ease of handling.

[0057] Furthermore, the resin having the structural unit represented by structural formula (2) has a five-membered ring lactam structure, which improves its solubility in certain organic solvents (mainly polar solvents), thereby reducing the viscosity of the molding fluid. For example, this allows for the proper ejection of the molding fluid using an inkjet method. In addition, when the resin having the structural unit represented by structural formula (2) is used in combination with organic solvents such as component 1 (cyclic esters (lactones), etc.) and component 2 (glycol diethers), as described later, the viscosity of the molding fluid can be further reduced. Because the viscosity of the molding fluid can be reduced in this way, the resin having the structural unit represented by structural formula (2) can be included in the molding fluid in high mass (for example, 15.0% by mass or more relative to the mass of the molding fluid). This further improves the flexural strength of the molded object and the solidified material before sintering, such as the unsintered body derived from the molded object.

[0058] The softening point of the resin having the structural unit represented by structural formula (2) is preferably 70°C or higher, more preferably 80°C or higher, and even more preferably 90°C or higher. Furthermore, it is preferably 180°C or lower, more preferably 170°C or lower, and even more preferably 160°C or lower.

[0059] The number-average molecular weight (Mn) of the resin having the structural unit represented by structural formula (2) is preferably 3,000 to 50,000, and more preferably 5,000 to 40,000. Having the number-average molecular weight (Mn) within this range allows for both improved strength and molding accuracy, as well as reduced viscosity of the molding fluid and increased resin concentration in the molding fluid.

[0060] Specific examples of resins having the structural unit represented by structural formula (2) include, for example, polyvinylpyrrolidone resin. Both commercially available and synthetic products can be used.

[0061] The content of the resin having the structural unit represented by structural formula (2) is preferably 7.0% by mass or more, more preferably 10.0% by mass or more, even more preferably 11.0% by mass or more, and particularly preferably 13.0% by mass or more, relative to the mass of the molding fluid. Furthermore, it is preferably 25.0% by mass or less, more preferably 20.0% by mass or less, and even more preferably 15.0% by mass or less. A content of 7.0% by mass or more further improves the flexural strength of the molded object and the solidified material before sintering, such as the unsintered body derived from the molded object. Furthermore, a content of 25.0% by mass or less further reduces the viscosity of the molding fluid, allowing the molding fluid to be appropriately ejected, for example, by an inkjet method.

[0062] <<Organic Solvents>> The molding fluid contains an organic solvent. The aforementioned organic solvent is a liquid component used to keep the molding fluid in a liquid state at room temperature. Furthermore, it is preferable that the molding fluid contains an organic solvent, thereby being a non-aqueous molding fluid. In this disclosure, "non-aqueous molding fluid" refers to a molding fluid that contains an organic solvent as a liquid component, and in which the component having the largest mass is the organic solvent. Preferably, the content of the organic solvent relative to the liquid component content in the "non-aqueous molding fluid" is 90.0% by mass or more, and more preferably 95.0% by mass or more. This is because, with non-aqueous molding fluids, solubility is improved, particularly in resins having structural units represented by structural formula (1), and the viscosity of the molding fluid decreases. Furthermore, non-aqueous 3D printing fluids can sometimes be described as 3D printing fluids that are substantially water-free. This allows the 3D printing fluid to be applied even when the materials constituting the metal particles are highly reactive metals, or in other words, water-reactive materials (e.g., aluminum, zinc, and magnesium). For example, aluminum forms an aluminum hydroxide film when it comes into contact with water, so a high water content in the 3D printing fluid can lead to a decrease in the sintering density of the sintered body. However, this problem can be suppressed by using a 3D printing fluid that does not contain water. As another example, aluminum is difficult to handle because it generates hydrogen when it comes into contact with water, but this problem can also be suppressed by using a 3D printing fluid that does not contain water.

[0063] Examples of the aforementioned organic solvents include n-octane, m-xylene, solvent naphtha, diisobutyl ketone, 3-heptanone, 2-octanone, acetylacetone, butyl acetate, amyl acetate, n-hexyl acetate, n-octyl acetate, ethyl butyrate, ethyl valerate, ethyl caprylate, ethyl octanoate, ethyl acetoacetate, ethyl 3-ethoxypropionate, diethyl oxalate, diethyl malonate, diethyl succinate, diethyl adipate, bis-2-ethylhexyl maleate, triacetate Examples include tributyline, 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 may be used individually or in combination of two or more.

[0064] When using a resin having a structural unit represented by structural formula (1), the organic solvent used in combination is not particularly limited, but it is preferable to use an organic solvent having at least one structure selected from the group consisting of alkoxy groups, ether bonds, and ester bonds, more preferably an organic solvent having an ether bond, and particularly preferably alkylene glycol dialkyl ethers. When these organic solvents are used, the solubility of the resin having a structural unit represented by structural formula (1) is further improved, and the viscosity of the molding liquid can be further reduced, allowing the molding liquid to be appropriately ejected, for example, by an inkjet method. In this disclosure, "alkylene glycol dialkyl ethers" refers to R1-(O-R2) mRepresented as -OR3, R1 and R3 are each independently alkyl groups having 1 to 5 carbon atoms, which may be linear or branched, and preferably have 1 or 2 carbon atoms. R2 is an alkylene group having 2 to 5 carbon atoms, which may be linear or branched, and more preferably have 2 or 3 carbon atoms. m represents an integer between 1 and 5, and more preferably 2 or 3. Specific examples of alkylene glycol dialkyl ethers include, for example, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, diethylene glycol ethyl methyl ether, and diethylene glycol butyl methyl ether. Among these, diethylene glycol dimethyl ether and triethylene glycol dimethyl ether are preferred, and triethylene glycol dimethyl ether is more preferred.

[0065] When using a resin having a structural unit represented by structural formula (2), it is preferable that the organic solvent used in combination be a polar solvent. Specifically, it is preferable to use at least one selected from the group consisting of cyclic esters (lactones), cyclic ketones, and alkylene glycol monoalkyl ethers as component 1, and it is even more preferable to use at least one selected from the group consisting of alkylene glycol dialkyl ethers in addition to at least one selected from component 1 as component 1. When these organic solvents are used, the solubility of the resin having a structural unit represented by structural formula (2) is further improved, and the viscosity of the molding liquid can be further reduced, allowing the molding liquid to be appropriately ejected, for example, in an inkjet method. From the viewpoint of further improving the solubility of the resin having a structural unit represented by structural formula (2), it is preferable that component 1 is from the group consisting of cyclic esters (lactones) and cyclic ketones. When using a resin having structural units represented by structural formula (2), and using both at least one selected from component 1 and at least one selected from component 2 as the organic solvent, the mass ratio (component 1 / component 2) of the total amount of component 1 to the total amount of component 2 is preferably 60 / 40 to 100 / 0. This is because a ratio of 60 / 40 to 100 / 0 further improves the solubility of the resin having structural units represented by structural formula (2), and consequently further reduces the viscosity of the molding fluid. Specific examples of component 1, which is a group consisting of cyclic esters (lactones), cyclic ketones, and alkylene glycol monoalkyl ethers, include, for example, γ-butyrolactone, propylene carbonate, and cyclohexanone. Specific examples of component 2, which is comprised of alkylene glycol dialkyl ethers, include, for example, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, diethylene glycol ethyl methyl ether, and diethylene glycol butyl methyl ether, among which diethylene glycol dimethyl ether and triethylene glycol dimethyl ether are preferred. In this disclosure, "alkylene glycol monoalkyl ethers" refers to R4-(O-R5) n Represented as -OH, R4 is an alkyl group having 1 to 5 carbon atoms, which may be linear or branched. R5 is an alkylene group having 2 to 5 carbon atoms, which may be linear or branched. n is an integer between 1 and 5. Furthermore, if you want to further reduce the viscosity of the molding fluid, using a resin with structural units represented by structural formula (2) is more affected by the type of organic solvent used than using a resin with structural units represented by structural formula (1). Therefore, it is necessary to selectively use the organic solvents (component 1 and component 2) as described above. For this reason, from the perspective of broadening the range of material selection when preparing the molding fluid, it is preferable to use a resin with structural units represented by structural formula (1) rather than a resin with structural units represented by structural formula (2).

[0066] The content of the organic solvent 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, relative to the mass of the molding fluid. When the content is 60.0% by mass or more and 95.0% by mass or less, the solubility of the resin is further improved, and the viscosity of the molding fluid can be further reduced, allowing the molding fluid to be appropriately ejected, for example, by an inkjet method. In addition, drying of the molding fluid is suppressed in the molding fluid dispensing means, and a molding fluid with excellent ejection stability can be provided.

[0067] The mass ratio of the amount of organic solvent to the amount of resin (organic solvent / resin) is preferably 75 / 25 or more and 95 / 5 or less. If it is 75 / 25 or more, the solubility of the resin is further improved, and the viscosity of the molding fluid can be further reduced, allowing the molding fluid to be appropriately ejected, for example, by an inkjet method. If it is 95 / 5 or less, the flexural strength of the molded object and the solidified material before sintering, such as the unsintered body derived from the molded object, is further improved.

[0068] The total amount of the organic solvent and the resin is preferably 90.0% by mass or more, more preferably 95.0% by mass or more, more preferably 99.0% by mass or more, and even more preferably 99.5% by mass or more, relative to the mass of the molding liquid. Furthermore, it is not necessary for the product to substantially contain components other than organic solvents and resins. Furthermore, the statement that a molding fluid substantially contains no components other than organic solvents and resins means that no components other than organic solvents and resins are actively used as materials during the manufacture of the molding fluid, or that the content of components other than organic solvents and resins in the molding fluid is below the detection limit when using publicly known and commonly understood technical methods. When the total amount of the organic solvent and resin is 90.0% by mass or more of the mass of the molding fluid, the resin content in the molding fluid increases, and the flexural strength of the molded object and the unsintered solidified material derived from the molded object is further improved. In addition, when the content of components other than organic solvents and resins (for example, materials that are insoluble in the molding fluid, such as metal nanoparticles) decreases or is substantially eliminated, the viscosity of the molding fluid decreases, the dispensing stability of the molding fluid improves, and the storage stability of the molding fluid also improves.

[0069] The viscosity of the organic solvent is preferably low, specifically, at 25°C, it is preferably 5.0 mPa·s to 50.0 mPa·s, and more preferably 8.0 mPa·s to 30.0 mPa·s. When the viscosity of the organic solvent is within the above range, the viscosity of the molding fluid containing the organic solvent is also easily reduced, which stabilizes the ejection from molding fluid dispensing means such as inkjet heads, and accurate ejection of the molding fluid improves the bending strength of the molded object and the solidified material before sintering, such as the unsintered body derived from the molded object, and also improves dimensional accuracy. Viscosity can be measured, for example, in accordance with JIS K7117.

[0070] The boiling point of the organic solvent is preferably high, specifically 150°C or higher, and more preferably 180°C or higher. When the molding liquid is ejected using an inkjet method or the like, a high boiling point of the organic solvent suppresses drying of the molding liquid at or near the nozzle, thereby suppressing nozzle clogging caused by precipitated resin. High boiling point organic solvents are not particularly limited, but examples 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).

[0071] <<Additives>> The molding liquid may appropriately contain surfactants, drying inhibitors, viscosity modifiers, penetrating agents, defoaming agents, pH adjusters, preservatives, fungicides, colorants, preservatives, stabilizers, etc., depending on the purpose. Conventionally known materials can be used.

[0072] <<Component B>> -water- The molding fluid contains virtually no water. In this disclosure, "substantially water-free" means that the water content is 10.0% by mass or less relative to the mass of the molding fluid, preferably 5.0% by mass or less, more preferably 3.0% by mass or less, even more preferably 1.0% by mass or less, and particularly preferably the molding fluid contains no water at all. By substantially eliminating water from the molding fluid, the solubility of the resin is further improved, and consequently, the viscosity of the molding fluid can be further reduced. Furthermore, the formation of hydrogels containing a large amount of water around the resin is suppressed, and the resulting increase in the viscosity of the molding fluid is also suppressed. As a result, for example, the molding fluid can be appropriately ejected using an inkjet method. In this disclosure, "the molding fluid does not contain water" means that water is not actively used as a material during the manufacture of the molding fluid, or that the water content in the molding fluid is below the detection limit when using publicly known and commonly technical methods. Furthermore, because the molding fluid contains virtually no water, it can be used even if the materials constituting the metal particles are highly reactive metals, in other words, water-reactive materials (e.g., aluminum, zinc, and magnesium). For example, aluminum forms an aluminum hydroxide film when it comes into contact with water, so a high water content in the molding fluid can lead to a decrease in the sintering density of the sintered body. However, this problem is suppressed because the molding fluid does not contain water. As another example, aluminum is difficult to handle because it generates hydrogen when it comes into contact with water, but this problem is also suppressed because the molding fluid does not contain water.

[0073] There are no particular restrictions on the means of applying the molding fluid, and it can be appropriately selected according to the purpose. Examples include a dispenser system, a spray system, and an inkjet system. Among these, the dispenser system is excellent in droplet quantity, but the coating area is small. The spray system can easily form fine ejected material, has a wide coating area and excellent coating performance, but droplet quantity is poor, and the molding fluid scatters due to the spray flow. For this reason, the inkjet system is preferred. Compared to the spray system, the inkjet system has the advantage of better droplet quantity and a wider coating area compared to the dispenser system, and is preferred in that it can form complex molded objects accurately and efficiently.

[0074] When using the inkjet method, the means for applying the molding fluid by ejecting it is an inkjet head having a nozzle for ejecting the molding fluid. Suitable inkjet heads can be those from known inkjet printers. Examples of inkjet heads from inkjet printers include the RICOH MH / GH SERIES industrial inkjet printers manufactured by Ricoh Co., Ltd. Examples of inkjet printers include the SG7100, also manufactured by Ricoh Co., Ltd.

[0075] The molding fluid supplied to the molding fluid dispensing means may be contained in a molding fluid storage section. The molding fluid storage section is a container or other component that holds the molding fluid, and examples include a storage tank, bag, cartridge, or tank.

[0076] <Lamination process> The method for manufacturing a three-dimensional object according to the present invention may include a lamination step in which a laminate is formed by sequentially repeating a powder layer formation step and a molding liquid application step. The aforementioned "laminated structure" is a structure in which multiple powder layers, each having a region to which a molding fluid has been applied, are stacked. In this case, the structure may not contain any three-dimensional object that maintains a certain three-dimensional shape internally, or it may contain a three-dimensional object that maintains a certain three-dimensional shape internally.

[0077] The lamination process includes a step of placing powder on a thin layer (powder layer formation step) and a step of applying a molding liquid onto the thin layer (molding liquid application step), thereby forming a region of the powder layer to which the molding liquid has been applied. Furthermore, the lamination process includes a step of placing (laminating) powder onto a thin layer, which is a powder layer having regions to which the molding liquid has been applied, in the same manner as described above (powder layer formation step), and a step of applying the molding liquid onto the thin layer (molding liquid application step), thereby forming regions to which the molding liquid has been applied in the newly laminated powder layer. Furthermore, in this process, the area where the molding fluid is applied in the uppermost layer of stacked powder is continuous with the area where the molding fluid is applied in the lower layer of powder. As a result, an area with a molding fluid thickness equivalent to two layers of powder is obtained.

[0078] <Solidification process and solidification means> The solidification step is a step of solidifying the molded object to obtain a solidified product. The solidification means is a means for solidifying the molded object to obtain a solidified product.

[0079] "Solidification" refers to the process of maintaining a certain shape. A "solidified object" is a structure that has a three-dimensional shape that is maintained. Furthermore, solidified material refers to material that has not undergone the excess powder removal process, which removes excess powder that does not constitute a three-dimensional object. There are no particular restrictions on the method for solidifying the aforementioned molded object; for example, heating is one possible method.

[0080] The heating temperature in the solidification step is preferably higher than the softening point Tg (°C) of the resin, and more preferably between Tg (°C) and Tg + 150 (°C). As a result, the resin functions as a binder that binds metal particles together in the area where the molding fluid is applied, enabling the formation of molded objects and unsintered solidified materials derived from the molded objects. There are no particular restrictions on the solidification method; for example, a dryer or a constant temperature and humidity chamber can be used.

[0081] <Excess powder removal process and means for removing excess powder> The excess powder removal step involves removing the molding powder adhering to the solidified material using an octanol / water partition coefficient (logP ow This is a step of removing the substance using a cleaning solution containing a hydrocarbon solvent whose value is 4.5 or higher. The excess powder removal means removes the molding powder adhering to the solidified material using an octanol / water partition coefficient (logP ow This method involves removing the substance using a cleaning solution containing a hydrocarbon solvent with a value of 4.5 or higher.

[0082] The excess powder removal step is a step of removing excess powder, which is powder adhering to the solidified material, to obtain an unsintered body. The term "unsintered body" refers to a three-dimensional object that maintains a certain three-dimensional shape and has undergone an excess powder removal process to remove excess powder that does not constitute a solidified material. Preferably, it refers to a three-dimensional object from which excess powder is substantially absent. The "unsintered body" is sometimes referred to as a "green body."

[0083] In the excess powder removal step, the method for "removing the molding powder adhering to the solidified material with the cleaning solution" is not particularly limited as long as the excess molding powder adhering to the solidified material can be removed using the cleaning solution, and can be appropriately selected according to the purpose. For example, a preferred method is to immerse the solidified material in the cleaning solution and remove the molding powder adhering to the solidified material by ultrasonic treatment. Furthermore, in the excess powder removal step, in addition to "removing the molding powder adhering to the solidified material with the cleaning solution," it is preferable to combine this with, for example, a step of removing excess powder from the surface of the solidified material by air blowing.

[0084] The solidified material after the solidification process is embedded in excess powder, which is powder that has not been treated with the molding fluid. When the solidified material is removed from this embedded state, the excess powder adheres to the surface and interior of the solidified material, making it difficult to remove them easily. Furthermore, the process becomes even more difficult if the surface shape of the solidified material is complex or if the internal structure of the solidified material is like a flow channel. Since the solidified material before sintering, which is formed using a typical binder jetting method, does not have high strength, increasing the pressure of the air blow from the blowing device may cause the solidified material to collapse. On the other hand, the solidified product formed using the molding liquid of this disclosure is formed from the above-mentioned resin, and therefore has improved bending strength and strength that can withstand the pressure of an air blow. In this case, the strength of the solidified product is preferably 3 MPa or more, and more preferably 5 MPa or more, based on a three-point bending stress.

[0085] In the method for manufacturing a three-dimensional object and the apparatus for manufacturing a three-dimensional object of the present invention, the octanol / water partition coefficient (logP) of the cleaning solution is ow The value is 4.5 or higher, preferably 5.0 or higher, and more preferably 5.0 or higher and 8.0 or lower. Also, the octanol / water partition coefficient (logP ow If the hydrocarbon solvent has a value of 4.5 or higher, it is possible to remove only the excess powder from the unsintered body after the binder resin (molding liquid) has been applied, without dissolving the binder resin. In the method for manufacturing a three-dimensional object and the apparatus for manufacturing a three-dimensional object of the present invention, the cleaning solution is preferably the cleaning solution for removing excess powder of the present invention.

[0086] <Other processes and other means> The aforementioned other processes are not particularly limited and can be appropriately selected depending on the purpose. Examples include drying, degreasing, sintering, and post-processing steps. The aforementioned other means are not particularly limited and can be appropriately selected depending on the purpose. Examples include drying means, degreasing means, sintering means, and post-processing means.

[0087] <<Drying process and drying means>> The present invention preferably includes a drying step in which the unsintered body is dried to remove any remaining liquid components such as cleaning solution. The drying process may remove not only liquid components such as cleaning solutions contained in the unsintered body, but also organic matter. As the drying means, for example, a known dryer, a constant temperature and humidity chamber, etc., can be used.

[0088] <<Degreasing process and degreasing means>> The present invention preferably includes a degreasing step in which an unsintered body is heated to remove resin and other substances derived from the applied molding fluid, thereby obtaining a degreased body. The aforementioned "degreased body" is a three-dimensional object obtained by degreasing an unsintered body of organic components such as the resin mentioned above. The degreasing step uses a degreasing means to set the temperature to a temperature above the thermal decomposition temperature of the organic components such as the resin, and above the melting point or solidus temperature of the material (metal) constituting the metal particles (for example, AlSi 10 If using Mg particles, the unsintered body is heated at a temperature lower than approximately 570°C for a certain period of time (for example, 1 to 10 hours) to decompose and remove the organic components. Examples of the degreasing means include known sintering furnaces and electric furnaces.

[0089] <<Sintering process and sintering means>> The method for manufacturing a three-dimensional object of the present invention preferably includes a sintering step of heating a solidified material (unsintered body) or a degreased body to obtain a sintered body. A "sintered body" is a three-dimensional object formed by the integration of metal materials constituting metal particles, and is manufactured by sintering a solidified material (unsintered body) or a degreased body. The sintering process uses sintering means to raise the solidus temperature of the metal material constituting the metal particles (for example, AlSi 10If Mg particles are used, the temperature must be above approximately 570°C and above the liquidus temperature (for example, AlSi 10 If using Mg particles, the degreased body is heated at a temperature of approximately 600°C or lower for a certain period of time (for example, 1 to 10 hours) to integrate the metal material that makes up the metal particles. Examples of the sintering means include a known sintering furnace, but it may also be the same means as the degreasing means described above. Furthermore, the degreasing step and the sintering step may be performed consecutively.

[0090] <<Post-processing steps and post-processing means>> The method for manufacturing a three-dimensional object according to the present invention preferably includes a post-processing step that performs post-processing on the sintered body. The aforementioned post-processing steps are not particularly limited and can be appropriately selected according to the purpose. Examples include surface protection treatment steps and painting steps. The post-processing means are not particularly limited and can be appropriately selected depending on the purpose. Examples include surface protection treatment means and coating means.

[0091] [The process of creating the sculpture] The fabrication process in the manufacturing method of the three-dimensional object described herein will be explained with reference to Figures 1A to 1E. Figures 1A to 1E are schematic diagrams showing an example of the operation of the manufacturing apparatus for three-dimensional objects.

[0092] First, we will explain the state in which the first powder layer 30 has been formed on the molding stage of the molding tank. When forming the next powder layer on the first powder layer 30, as shown in Figure 1A, the supply stage 23 of the supply tank is raised and the molding stage 24 of the molding tank is lowered. At this time, the lowering distance of the molding stage 24 is set so that the distance (layer pitch) between the upper surface of the powder layer in the molding tank 22 and the lower part (lower tangential part) of the flattening roller 12 is Δt1. The distance Δt1 is not particularly limited, but it is preferably several tens to 100 μm.

[0093] In this disclosure, the flattening roller 12 is positioned such that there is a gap between it and the upper surfaces of the supply tank 21 and the molding tank 22. Therefore, when the powder 20 is transferred and supplied to the molding tank 22 for flattening, the upper surface of the powder layer is higher than the upper surfaces of the supply tank 21 and the molding tank 22. This reliably prevents the flattening roller 12 from contacting the upper surfaces of the supply tank 21 and the molding tank 22, thereby reducing damage to the flattening roller 12. If the surface of the flattening roller 12 is damaged, streaks may appear on the surface of the powder layer 31 (see Figure 1D) supplied to the molding tank 22, making it easier for the flatness to decrease.

[0094] Next, as shown in Figure 1B, the powder 20, which is positioned higher than the upper end surface of the supply tank 21, is transferred and supplied to the build tank 22 by moving the flattening roller 12 toward the build tank 22 while rotating it in the direction of the arrow (powder supply). Furthermore, as shown in Figure 1C, the flattening roller 12 is moved parallel to the stage surface of the build stage 24 of the build tank 22 to form a powder layer 31 of a predetermined thickness Δt1 on the build tank 22 of the build stage 24 (flattening). At this time, any excess powder 20 that was not used to form the powder layer 31 falls into the excess powder receiving tank 29. After the powder layer 31 is formed, the flattening roller 12 is moved toward the supply tank 21 and returned to its initial position (origin position) as shown in Figure 1D (return).

[0095] Here, the flattening roller 12 is designed to move while maintaining a constant distance from the upper end surfaces of the molding tank 22 and the supply tank 21. By moving while maintaining a constant distance, the flattening roller 12 can transport the powder 20 onto the molding tank 22, while simultaneously forming a powder layer 31 of uniform thickness h (corresponding to the layering pitch Δt1) on the molding tank 22 or on the already formed solidified layer 30. In the following explanation, the thickness h of the powder layer 31 and the layering pitch Δt1 may not be distinguished, but unless otherwise specified, they refer to the same thickness and have the same meaning. Alternatively, the thickness h of the powder layer 31 may be determined by actually measuring it, in which case it is preferable to use the average value of multiple locations.

[0096] Subsequently, as shown in Figure 1E, droplets 10 of the molding fluid are discharged from the head 52 of the liquid discharge unit to laminate and form a molding fluid-coated layer 30 of the desired shape on the next powder layer 31. Next, the powder layer formation process and the molding fluid application process described above are repeated to form and laminate a new molding fluid-coated layer 30. At this time, the new molding fluid-coated layer 30 and the molding fluid-coated layer 30 below it become one. Thereafter, the powder layer formation process and the molding fluid application process are repeated to manufacture a laminate (molded object).

[0097] (Set of molding fluid and cleaning solution) The present invention provides a set of molding fluid and cleaning fluid comprising a molding fluid containing resin and an octanol / water partition coefficient (logP ow A cleaning solution for removing excess powder containing a hydrocarbon solvent with a value of 4.5 or higher, and further containing other components as needed. In the set of molding fluid and cleaning fluid of the present invention, the "molding fluid" and "cleaning fluid for removing excess powder" are the same as those described in the "cleaning fluid for removing excess powder" and "method for manufacturing a three-dimensional molded object" of the present invention. The "excess powder removal cleaning solution" in the molding solution and cleaning solution set of the present invention can be used exclusively and suitably to remove excess powder from solidified products formed using molding powder. [Examples]

[0098] The following describes embodiments of the present invention, but the present invention is not limited in any way to these embodiments.

[0099] <Preparation of molding fluids 1-3> The materials shown in Table 2 were individually mixed and stirred with a magnetic stirrer for 4 hours while being heated at 70°C. After 4 hours, heating was stopped, and stirring was maintained until the mixture reached room temperature to prepare molding solutions 1-3.

[0100] [Table 2] The numbers listed in Table 2 represent mass percentages.

[0101] The details of the materials listed in Table 2 are shown below. <Organic solvents> • Triglyceride (triethylene glycol dimethyl ether, manufactured by Toho Chemical Industry Co., Ltd.: Product name: Highsolve MTM, logP ow (Value: -0.48) • γ-butyrolactone (manufactured by Tokyo Chemical Industry Co., Ltd., logP ow (Value: -0.6) <Resin having structural units represented by structural formula (1)> -JMR-10LL (Vinyl acetate resin, partially saponified polyvinyl acetate, degree of saponification: 10 mol%, manufactured by Nippon Vi-Poval Co., Ltd.)- ·Structural formula [ka] • Percentage of hydrophobic parts in the resin: 89 mol% ~ 91 mol% • Percentage of hydrophilic portion in the resin: 9 mol% ~ 11 mol% • Temperature: 30℃~40℃ ·Softening point: approx. 105℃ ·Number average molecular weight (Mn): 20000 or less ·Ingredient concentration: 99% by mass or more • Can dissolve 10g or more in 100g of triglyceride (triethylene glycol dimethyl ether) at 25℃. - S-Rec BL-10 (vinyl acetate resin, polyvinyl butyral, manufactured by Sekisui Chemical Co., Ltd.) - ·Structural formula [ka] • Percentage of hydrophobic parts in the resin: 72 mol% (3 mol% of structural units represented by structural formula (1), and 69 mol% of structural units represented by structural formula (3)) • Percentage of hydrophilic portion in the resin: 28 mol% Tg: 67℃ ·Softening point: 100℃~120℃ ·Number average molecular weight (Mn): Approx. 15000 ·Ingredient concentration: 99% by mass or more • Can dissolve 10g or more in 100g of γ-butyrolactone at 25℃. <Resin having structural units represented by structural formula (2)> -PVP K15 (Polyvinylpyrrolidone, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)- ·Structural formula [ka] ·Softening point: 100℃~130℃ ·Number average molecular weight (Mn): Approximately 10,000 or less ·Ingredient concentration: 90% by mass or more • Can dissolve 10g or more in 100g of γ-butyrolactone at 25℃.

[0102] Next, the prepared molding fluids 1-3 and the powder containing metal particles (AlSi 10 Using Mg powder (manufactured by Toyo Aluminum Co., Ltd., Si10Mg-30BB, volume-average particle size: 35 μm, metal particle surface not coated with resin)), each solidified product (unsintered body, green body) was manufactured as follows. 1) First, using a known manufacturing apparatus for molded objects as shown in Figures 1A to 1E, powder was transferred from the supply-side powder storage tank to the molding-side powder storage tank, and a thin layer of powder with an average thickness of 100 μm was formed on the stage. 2) Next, the molding fluid was applied to the surface of the thin layer formed from the powder by ejecting it from the nozzle of a known inkjet ejection head, and the binder resin contained in the curing fluid was arranged around the core material. The ejection area for the molding fluid was a rectangle with a length of 40 mm and a width of 10 mm. 3) Next, steps 1) and 2) were repeated until the total average thickness reached 3 mm, and thin layers of solidified powder were sequentially laminated. A drying process was then carried out using a dryer under optimal heating conditions according to the softening point of each resin to obtain a solidified product (unsintered body). 4) After drying, excess powder was removed from the solidified material (unsintered body) by air blowing, and then a solidified material (unsintered body) made with molding liquid 1 was obtained. For each molding fluid (1-3), two solidified (unsintered) samples were prepared. Hereafter, these solidified (unsintered) samples will be simply referred to as "unsintered samples."

[0103] Next, the fabricated unsintered bodies were evaluated for their "flexural strength before and after immersion in the cleaning solution" and "condition of the unsintered bodies after immersion in the cleaning solution."

[0104] <Bending strength of unsintered body before and after immersion in cleaning solution> -Before immersion in cleaning solution- The bending strength of the unsintered body before immersion in the cleaning solution was measured by the bending strength of the unsintered body prepared in 4) above, and evaluated based on the following evaluation criteria. A universal testing machine (Autograph, model AG-I) manufactured by Shimadzu Corporation was used to measure the bending strength, and a 1kN load cell and a three-point bending jig were used. 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, with the stress at the fracture point being defined as the maximum stress. [Evaluation Criteria] A: Bending strength of 5 MPa or more B: Bending strength between 3 MPa and less than 5 MPa C: Bending strength of 2.7 MPa or more and less than 3 MPa D: Bending strength is less than 2.7 MPa -After immersion in cleaning solution- The bending strength of the unsintered body after immersion in the cleaning solution was measured by immersing the unsintered body prepared in 4) above in each of the cleaning solutions shown in Tables 3 to 6 in a tray and immersing it in an ultrasonic bath for 30 minutes, then measuring the bending strength of the unsintered body in the same manner as before immersion in the cleaning solution. The evaluation method and evaluation criteria were the same as before immersion in the cleaning solution.

[0105] <State of the unsintered body after immersion in cleaning solution> In evaluating the "flexural strength of the unsintered body after immersion in the cleaning solution," the state of the unsintered body after immersion in the cleaning solution was visually observed and evaluated based on the following evaluation criteria. A result of "○" indicates that there are no problems with use. Figures 2A to 15B show photographs of the state of the unsintered body immediately after immersion in the cleaning solution and after immersion in an ultrasonic bath for 30 minutes. Figures 2A and 2B show the results of Example 1, Figures 3A and 3B show the results of Example 2, Figures 4A and 4B show the results of Example 3, Figures 5A and 5B show the results of Example 4, Figures 6A and 6B show the results of Comparative Example 1, Figures 7A and 7B show the results of Comparative Example 2, Figures 8A and 8B show the results of Comparative Example 3, Figures 9A and 9B show the results of Example 5, Figures 10A and 10B show the results of Example 6, Figures 11A and 11B show the results of Comparative Example 4, Figures 12A and 12B show the results of Comparative Example 5, Figures 13A and 13B show the results of Example 7, Figures 14A and 14B show the results of Example 8, and Figures 15A and 15B show the results of Comparative Example 6. [Evaluation Criteria] ○: No change in the shape of the unsintered body from before immersion. △: The edges of the unsintered body are crumbling and returning to powder. ×: The shape of the unsintered material has collapsed and returned to powder.

[0106] [Table 3]

[0107] [Table 4]

[0108] [Table 5]

[0109] [Table 6]

[0110] The results from Examples 1-8 showed that if the octanol / water partition coefficient logPow value was 4.5 or higher, there was no change in the unsintered body before and after immersion in the cleaning solution, and it could be used as a cleaning solution to remove excess powder while maintaining its shape. Furthermore, Examples 1-8 showed that there was no decrease in the physical strength (flexural strength) of the unsintered body before and after immersion in the cleaning solution. Furthermore, from the results of Comparative Examples 1-5, even in hydrocarbon solvents composed only of carbon and hydrogen, logP is present when there are double bonds or short molecular chains. ow The values ​​became low, and the unsintered body disintegrated or partially lost its shape when immersed in the cleaning solution. Furthermore, the results from Comparative Example 6 showed that when the logPow value was extremely low, the unsintered body completely reverted to powder.

[0111] Examples of the present invention are as follows: <1> A cleaning solution for removing excess powder used to remove excess powder from solidified products formed using molding powder, Octanol / Water partition coefficient (logP) ow This cleaning solution for removing excess powder is characterized by containing a hydrocarbon solvent with a value of 4.5 or higher. <2> The molding powder is a powder containing metal particles that are not coated with resin. <1> This is a cleaning solution for removing excess powder as described above. <3> The octanol / water partition coefficient (logP) of the hydrocarbon solvent ow The value) is 5.0 or greater. <1> from <2> This is a cleaning solution for removing excess powder as described in any of the above. <4> The hydrocarbon solvent does not contain a double bond in its molecule. <1> from <3> This is a cleaning solution for removing excess powder as described in any of the above. <5> The hydrocarbon solvent is a hydrocarbon having a linear structure with 7 to 15 carbon atoms. <1> from <4> This is a cleaning solution for removing excess powder as described in any of the above. <6> The hydrocarbon solvent contains at least one of decane, undecane, dodecane, tridecane, tetradecane, and p-menthane. <1> from <4> This is a cleaning solution for removing excess powder as described in any of the above. <7> A powder layer formation step in which a powder layer containing molding powder is formed, A molding liquid application step involves applying a molding liquid containing resin to the powder layer to form a molded object, A solidification step to solidify the molded object to obtain a solidified product, The molding powder adhering to the solidified material is subjected to an octanol / water partition coefficient (logP ow A process to remove excess powder using a washing solution containing a hydrocarbon solvent with a value of 4.5 or higher, This is a method for manufacturing a three-dimensional object, characterized by including [a specific element]. <8> The aforementioned resin is soluble in solvent A, The octanol / water partition coefficient (logP) of solvent A. ow The value) is -1.8 or greater and 3.4 or less. <7> This is a method for manufacturing three-dimensional objects as described above. <9> The molding powder is a powder containing metal particles that are not coated with resin. <7> from <8> This is a method for manufacturing a three-dimensional object as described in any of the following. <10> The molding liquid contains a resin having at least one of the structural units represented by the following structural formula (1) and the following structural unit represented by the following structural formula (2). <7> from <9> This is a method for manufacturing a three-dimensional object as described in any of the following. [ka] [ka] <11> The excess powder removal step includes removing the molding powder adhering to the solidified material by ultrasonic treatment. <7> from <10> This is a method for manufacturing a three-dimensional object as described in any of the above. <12> A molding liquid containing resin, Octanol / Water partition coefficient (logP) ow A cleaning solution for removing excess powder containing a hydrocarbon solvent with a value of 4.5 or higher, This is a set of molding fluid and cleaning fluid characterized by containing [specific ingredient / feature]. <13> The aforementioned resin is soluble in solvent A, The octanol / water partition coefficient (logP) of solvent A. ow The value) is -1.8 or greater and 3.4 or less. <12> This is a set of molding fluid and cleaning fluid as described. <14> A powder layer forming means for forming a powder layer containing molding powder, A molding liquid application means for applying a molding liquid containing resin to the powder layer to form a molded object, A solidification means for solidifying the molded object to obtain a solidified product, Remove the molding powder adhering to the solidified material, using an octanol / water partition coefficient (logP ow A cleaning solution containing a hydrocarbon solvent having a value of 4.5 or higher, and a cleaning solution container containing the cleaning solution. The apparatus for manufacturing three-dimensional molded objects is characterized by having an excess powder removal means for removing the molding powder adhering to the solidified material with the cleaning liquid. <15> The aforementioned resin is soluble in solvent A, The octanol / water partition coefficient (logP) of solvent A. ow The value) is -1.8 or greater and 3.4 or less. <14> This is a manufacturing apparatus for the three-dimensional objects described above.

[0112] The aforementioned <1> from <6> A cleaning liquid for removing excess powder as described in any of the above, <7> from <11> The method for manufacturing a three-dimensional object as described above, <12> from <13> A set of molding fluid and cleaning fluid as described in any of the above, and the <14> from <15> According to the manufacturing apparatus for three-dimensional objects described in any of the above, the conventional problems can be solved and the objectives of the present invention can be achieved. [Prior art documents] [Patent Documents]

[0113] [Patent Document 1] Japanese Patent Publication No. 2021-146669

Claims

1. A cleaning liquid for removing excess powder used to remove excess powder from a solidified product formed by a binder jetting method, which is applied to a molding powder containing metal particles using a molding liquid containing resin, Octanol / water partition coefficient (logP) ｏｗ It contains a hydrocarbon solvent whose value is 4.5 or higher. The resin is soluble in solvent A, A cleaning solution for removing excess powder, characterized in that the octanol / water dispersion coefficient (logP OW value) of solvent A is -1.8 or more and 3.4 or less.

2. The cleaning solution for removing excess powder according to claim 1, wherein the molding powder is a powder containing metal particles that are not coated with resin.

3. The octanol / water partition coefficient (logP) of the hydrocarbon solvent. ｏｗ A cleaning solution for removing excess powder according to any one of claims 1 to 2, wherein the value is 5.0 or greater.

4. The cleaning solution for removing excess powder according to any one of claims 1 to 3, wherein the hydrocarbon solvent does not contain double bonds in its molecule.

5. The cleaning liquid for removing excess powder according to any one of claims 1 to 4, wherein the hydrocarbon solvent is a hydrocarbon having 7 or more carbon atoms and 15 or fewer carbon atoms.

6. The cleaning solution for removing excess powder according to any one of claims 1 to 5, wherein the hydrocarbon solvent contains at least one of decane, undecane, dodecane, tridecane, tetradecane, and p-menthane.

7. A powder layer forming step comprising forming a powder layer containing a molding powder containing metal particles, A molding liquid application step involves applying a molding liquid containing resin to the powder layer to form a molded object, A solidification step to solidify the molded object to obtain a solidified product, The molding powder adhering to the solidified material is subjected to an octanol / water partition coefficient (logP ｏｗ A process to remove excess powder using a washing solution containing a hydrocarbon solvent with a value of 4.5 or higher, Includes, The resin is soluble in solvent A, A method for manufacturing a three-dimensional object, characterized in that the octanol / water dispersion coefficient (logP OW value) of the solvent A is -1.8 or more and 3.4 or less.

8. The method for manufacturing a three-dimensional object according to claim 7, wherein the molding powder contains metal particles that are not coated with resin.

9. A method for manufacturing a three-dimensional object according to any one of claims 7 to 8, wherein the molding liquid contains a resin having at least one of the structural units represented by the following structural formula (1) and the structural units represented by the following structural formula (2). 【Chemistry 1】 【Chemistry 2】

10. A method for manufacturing a three-dimensional object according to any one of claims 7 to 9, wherein the excess powder removal step includes removing the molding powder adhering to the solidified material by ultrasonic treatment.

11. A set of molding liquid and cleaning liquid used to remove excess powder from a solidified product formed by a binder jetting method, by applying a molding liquid containing resin to a molding powder containing metal particles, A molding liquid containing resin, Octanol / water partition coefficient (logP) ｏｗ A cleaning solution for removing excess powder containing a hydrocarbon solvent with a value of 4.5 or higher, Includes, The resin is soluble in solvent A, A set of molding fluid and cleaning fluid characterized in that the octanol / water dispersion coefficient (logP OW value) of solvent A is between -1.8 and 3.4.

Images