3D structure manufacturing method using casting mold made of water-soluble photocurable resin, and water-soluble photocurable resin composition for manufacturing casting mold

Abstract

Disclosed are a 3D structure manufacturing method using a casting mold made of a water-soluble photocurable resin, and a water-soluble photocurable resin composition for manufacturing a casting mold applied to the method, wherein, in manufacturing a 3D structure by using a casting mold, a casting mold for manufacturing a 3D structure is manufactured through a photocuring-based 3D printing technique by using a water-soluble photocurable resin that cures upon light irradiation and dissolves well in neutral or basic aqueous solutions, a base material for the 3D structure to be manufactured is injected in a liquid form into the casting mold manufactured as described above, followed by solidification, and then, the water-soluble photocurable resin forming the casting mold is dissolved and removed using water or a basic aqueous solution, thereby enabling the rapid and precise manufacture of 3D products in a wider variety of shapes and effectively expending the range of selectable product materials at the same time.

Description

Method for manufacturing a 3D structure using a casting mold made of a water-soluble photocurable resin and a water-soluble photocurable resin composition for manufacturing a casting mold

[0001] The present invention relates to a method for manufacturing a 3D structure using a casting mold made of a water-soluble photocurable resin, and to a water-soluble photocurable resin composition for manufacturing a casting mold applied thereto, and more particularly, to a method for manufacturing a 3D structure, which comprises manufacturing a casting mold for manufacturing a 3D structure through a 3D printing technique using a water-soluble photocurable resin having the property of being soluble in water or an alkaline aqueous solution after curing, injecting a base material of a 3D structure to be manufactured in a liquid form into the casting mold thus manufactured, solidifying the base material, and then dissolving and removing the water-soluble photocurable resin forming the casting mold using water or an alkaline aqueous solution, thereby enabling the rapid and precise manufacture of 3D structures of various shapes, and to a water-soluble photocurable resin composition for manufacturing a casting mold applied thereto.

[0002]

[0003] 3D printing technology, which has been widely used in various fields recently, has many advantages, but it still has a relatively slow printing speed and many limitations in the materials that can be used to manufacture 3D structures, making it difficult to mass-produce products and making it difficult to widely apply it to the production of products using various materials.

[0004] On the other hand, one of the representative production methods used to produce 3D structures before the introduction of 3D printing technology is the mold casting method.

[0005] Mold casting is a method of producing 3D structures by injecting a molten thermoplastic material or a chemically reactive liquid material into a mold in which a space in the shape of the product to be produced has been formed, solidifying the material injected into the mold through cooling or chemical reaction, manufacturing (casting) the product, and then separating the manufactured product and the mold.

[0006] In the production of products using this type of mold casting, structurally rigid hard molds are usually used. However, in order to separate the manufactured product from the mold without damage, especially when the shape or structure of the product is relatively complex, a complex mold design consisting of multiple parts and a very precise manufacturing and separation process are required.

[0007] In addition, in order to overcome the limitations of the hard mold casting described above, a casting method utilizing a soft mold using silicone, etc., which has been recently introduced, supports the effective separation of the silicone mold and the product to be produced to a certain extent without damage by utilizing the elasticity of the silicone forming the mold, even in cases where the structure of the product to be produced is a structure in which the inside is wider than the starting point of the cavity, but this also makes it impossible to apply a single mold to a deep cavity or a minus cavity structure that is considerably wider inward. As a result, as mentioned above, it is inevitable to design the mold in a way that multiple molds are individually manufactured and assembled for each part through a complex design composed of multiple parts, and then disassembled and disassembled after the product is produced, or to divide the product to be produced into multiple parts, cast each part, and then assemble and fasten them using an adhesive or other joining means.

[0008] However, this method ultimately increases the manufacturing cost of the mold and the time required for the manufacturing process, which not only leads to an increase in the time and cost required for product production, but also, in the case of products with internal cavities or severe negative cavity structures, it is inevitable to cast at least two or more parts separately and then assemble and fasten them, which inevitably requires a post-processing process for the fastening area, and especially in the case of products that require transparent properties, it is very difficult to completely remove traces of the boundary surface.

[0009] Recently, in order to overcome the limitations of the mold casting method, a method for manufacturing 3D structures using 3D printing has been actively developed, as disclosed in Patent Publication No. 10-2337392, etc. However, as briefly mentioned above, 3D printing technology requires a relatively long time for sequential printing process in 2D layers and removal of supporters and post-processing after printing the 3D structure, which makes it difficult to build a mass production system for the product. In addition, the applied material must also meet certain material property requirements according to each printing method, so it is difficult to effectively replace the production of products using various materials according to the existing method.

[0010]

[0011] The present invention is a method derived to more effectively overcome the limitations of the above-described prior art, and in the present invention, a casting mold for manufacturing a 3D structure through a 3D printing technique using a water-soluble photocurable resin having the property of being well dissolved in water or an alkaline aqueous solution after curing is manufactured, and a base material of a 3D structure to be manufactured is injected in a liquid state into the casting mold manufactured in this manner and solidified, and then the water-soluble photocurable resin forming the casting mold is dissolved and removed using water or an alkaline aqueous solution, thereby suggesting a method capable of effectively, quickly, and precisely manufacturing a 3D structure composed of a wider range of product materials and a complex structure, and at the same time, providing a water-soluble photocurable resin composition for manufacturing a casting mold that can be usefully utilized in the method.

[0012]

[0013] In order to achieve the above-described object, the present invention provides a method for manufacturing a 3D structure using a casting mold, comprising the steps of: using a water-soluble photocurable resin as a printing material, manufacturing a casting mold for manufacturing a 3D structure for casting the 3D structure through a photocuring 3D printing process; injecting a liquid casting material for forming a 3D structure into the mold; removing air bubbles remaining inside the mold using a vacuum chamber; curing the casting material injected into the mold; and immersing the casting mold in a state where the injected material is cured in an aqueous solution to dissolve and remove the mold.

[0014] In addition, as a material for manufacturing a melt-type casting mold that can be effectively utilized in the above-described manufacturing method, it includes at least two epoxy or (meth)acrylate reactors for photocuring reaction, and has a backbone structure containing nitrogen bond (-N-), ether bond (-O-), -OH, -COOH, -NH-, -NH2, -N-CO-, M-OH (M means metal), and sodium (Na). + )salt, -SO3 - M + (where M is H, Na or K) or N + X - (wherein, X is OH, Cl or BF4) 10 to 50 wt% of a photocurable water-soluble oligomer comprising at least one; one or two epoxy or (meth)acrylate reactive groups for photocuring reaction, and having a backbone structure comprising nitrogen bond (-N-), ether bond (-O-), -OH, -COOH, -NH-, -NH2, -N-CO-, M-OH (M means metal), sodium (Na) + )salt, -SO3 - M + (where M is H, Na or K) or N + X - (wherein, X is OH, Cl or BF4) comprises 50 to 90 wt% of a photocurable water-soluble monomer; and a photoinitiator added in a range of 1 to 10 wt% based on the total weight of the resin composition in which the photocurable water-soluble oligomer and the photocurable water-soluble monomer are blended. A water-soluble photocurable resin composition for manufacturing a melt-type casting mold is provided.

[0015]

[0016] The method for manufacturing a 3D structure using a casting mold made of a water-soluble photocurable resin according to the present invention has the advantage that a casting mold having a complex shape or structure can be manufactured relatively easily by manufacturing a casting mold for manufacturing a 3D structure through a 3D printing technique using a photocuring method, and at the same time, the photocurable resin constituting the mold is configured to have a property of dissolving well in water or an alkaline aqueous solution, so that after a product injected into the mold is solidified, the product manufactured by immersing the mold in water or an alkaline aqueous solution to dissolve it can be easily separated from the mold without damage, and furthermore, products having cavities formed inside or having a severe negative cavity structure can be easily manufactured.

[0017] In addition, the method for manufacturing a 3D structure using a casting mold made of a water-soluble photocurable resin according to the present invention has differences in the material of the mold, the method for manufacturing the mold, and the method for separating the product and the mold, but basically produces a product by applying a mold casting method similar to the conventional one, and thus has the advantage of being able to widely utilize various existing materials, such as wax or polymer oligomer, which have been applied to products produced through mold casting in the past, in the production of the product.

[0018] Furthermore, the photocurable resin composition provided by the present invention can be widely used in 3D printing using various light sources such as LCD, DLP or Laser due to its low viscosity and fast photocuring speed characteristics that allow for liquid application of about 100 cPs to 20,000 cPs, and can be easily used in SLA (Stereolithography) method using various light sources such as LCD, DLP or Laser. In addition, it does not dissolve in conventional organic solvents such as alcohol, acetone or ketones that are mainly used for washing 3D printed materials, but has the characteristic of easily dissolving in neutral or basic aqueous solutions. Therefore, a casting mold for manufacturing a 3D structure through a photocuring method 3D printing process is formed, and after the product injected into the mold is solidified, it is dissolved in the aqueous solution through a simple process of being immersed in water or a basic aqueous solution for a certain period of time, and can be easily separated without concern for damage to the structure or surface of the 3D structure solidified in the mold, so that it can be usefully used in the production of various 3D structures including complex shapes or cavity structures. Can be.

[0019] In addition, since the heat deflection temperature (HDT) of the photocurable resin after photocuring can be controlled by adjusting the components of the resin composition, there is an advantage in that it can be widely used in the production of 3D structures using various existing mold casting materials, including not only materials with relatively low melting points, such as wax shapes used in lost wax casting, but also polymer oligomers with high melting points of 200°C or higher.

[0020]

[0021] Figure 1 is a flowchart briefly showing the process of performing a method for manufacturing a 3D structure using a casting mold made of a water-soluble photocurable resin according to the present invention.

[0022] FIG. 2 is a drawing exemplarily showing a casting mold manufactured for producing a buckle according to one embodiment of the present invention.

[0023] FIG. 3 is a drawing showing an example of a buckle manufactured using a lost wax material according to a method for manufacturing a 3D structure using a casting mold made of a water-soluble photocurable resin according to the present invention.

[0024]

[0025] Hereinafter, several preferred embodiments of the present invention will be described in detail with reference to the drawings, but the present invention is not limited to the following embodiments without departing from the gist thereof.

[0026]

[0027] As briefly explained above, in the method for manufacturing a 3D structure according to the present invention, a casting mold for manufacturing a 3D structure is manufactured using a water-soluble photocurable resin as a base material.

[0028] Here, the resin composition used in the production of the casting mold for manufacturing a 3D structure according to the present invention is a water-soluble photocurable resin composition developed to be optimized for the production of the dissolution-type casting mold used in the present invention, and is a resin having the characteristic of being rapidly cured by a photoreaction such as ultraviolet (UV) light, and at the same time having the characteristic of being easily dissolved in a neutral to basic aqueous solution, and based on the above-described physical properties, it supports the relatively easy production of casting molds having various complex shapes and structures through a 3D printing process using a photocuring reaction, and at the same time, after the material injected into the mold is solidified into a 3D structure, it is immersed in water or an basic aqueous solution together with the solidified 3D structure and dissolved, thereby supporting the easy separation of the produced 3D structure from the mold without damage.

[0029]

[0030] In order to implement such characteristics, the water-soluble photocurable resin composition for manufacturing a melt-type casting mold according to the present invention is based on a mixture of a photocurable water-soluble oligomer and a photocurable water-soluble monomer having an epoxy or (meth)acrylate reactive group for a photocuring reaction, and may further include i) a photoinitiator for a photocuring reaction, ii) a water-soluble resin added to improve the processability of a casting mold, iii) a water-soluble filler added to improve the solubility of a cured casting mold, iv) a pigment for improving the precision of 3D printing when manufacturing a casting mold, and v) other additives, and is characterized by having a low viscosity of 20,000 cPs or less so that it can be effectively used in top-down or bottom-up 3D printing using DLP (Digital Light Processing), LCD (Liquid Crystal Display), laser, etc.

[0031]

[0032] Composition components of a water-soluble photocurable resin composition for manufacturing a melt-type casting mold

[0033] (1) Photocurable water-soluble oligomer

[0034] An oligomer having at least two epoxy or (meth)acrylate reactive groups for photocuring reaction, and having a nitrogen bond (-N-) or an ether bond (-O-) in the backbone structure, or other groups such as -OH, -COOH, -NH-, -NH2, -N-CO-, M-OH (M means metal), and sodium (Na) so that it can be easily dissolved in a neutral to basic aqueous solution. + )salt, -SO3 - M + (where M is H, Na or K) and N + X -(wherein, X includes OH, Cl or BF4), etc., and the molecular weight is usually in the range of 400 g / mole to 500,000 g / mole, and the viscosity at room temperature is 1,000 cPs or more or may exist in a solid state.

[0035]

[0036] (2) Photocurable water-soluble monomer

[0037] A monomer having one or two epoxy or (meth)acrylate reactive groups for photocuring reaction, and having a nitrogen bond (-N-) or ether bond (-O-) in the backbone structure, or other bonds such as -OH, -COOH, -NH-, -NH2, -N-CO-, M-OH (M means metal), and sodium (Na) so that it can be easily dissolved in a neutral to basic aqueous solution. + )salt, -SO3 - M + (where M is H, Na or K) and N + X - (wherein, X includes OH, Cl or BF4), and the molecular weight is usually 400 g / mole or less.

[0038]

[0039] (3) Photoinitiator

[0040] In the 3D printing process, the photoinitiator converts the light energy transmitted from the light source into chemical energy, thereby converting the light energy into chemical energy so that the photocurable water-soluble resin can be cured. Various photoinitiators commonly used in the photocuring reaction can all be used.

[0041] Photoinitiators can be broadly classified into radical initiators and cationic initiators. Commonly used radical initiators include benzophenone derivatives, benzyl ketones, monomeric hydroxyl ketones, polymeric hydroxyl ketones, a-amino ketones, acyl phosphine oxides, metallocenes, benzoin ethers, benzil ketals, a-hydroxyalkylphenones, a-aminoalkylphenones, etc., and commonly used cationic initiators include isopropyl thioxanthenones, arylsulphonium salts, and aryl iodonium salts. salts) etc. may be used.

[0042]

[0043] The water-soluble photocurable resin composition for manufacturing a melt-type casting mold according to the present invention can be formed by mixing the above-described photocurable water-soluble oligomer and the photocurable water-soluble monomer in a ratio of about 10 to 50 wt% and about 50 to 90 wt%, respectively. At this time, the mixing ratio can be appropriately adjusted according to the viscosity required by the 3D printer. Preferably, it is easy to implement effective viscosity characteristics when mixing about 20 to 40 wt% of the photocurable water-soluble oligomer and about 60 to 80 wt% of the photocurable water-soluble monomer.

[0044] In addition, the content of the photoinitiator added to the composition in which the above-described photocurable water-soluble oligomer and photocurable water-soluble monomer are mixed may also be added in an amount of about 1 to 10 wt% per 100 wt% of the composition, depending on the type and amount of light source applied to the 3D printer, and is preferably adjusted in the range of 2 to 5 wt%.

[0045] That is, the water-soluble photocurable resin composition for manufacturing a melt-type casting mold according to the present invention is a composition in which a photocurable water-soluble oligomer and a photocurable water-soluble monomer are mixed, and a photoinitiator for a photocuring reaction is added to complete the basic composition of the resin composition.

[0046]

[0047] Here, the photocurable water-soluble oligomer included in the resin composition performs the function of increasing the overall strength of the casting mold by increasing the physical hardness and elongation at break of the 3D printed product through photocuring, and various commercial products can be applied. For example, SU550, SU550A, SU560, SWA8048, SWA8071, SWA8083 of SOLTECH can be mentioned, and in addition, various other commercial products can be used.

[0048] In addition, in the case of the commercial products described above, they are often provided in a state mixed with water or other solvents. In this case, in order to more effectively secure the structural integrity of the casting mold during the 3D printing process, it is recommended to use a product with a water or solvent content of 10 wt% or less.

[0049] The photocurable water-soluble monomer included in the above resin composition provides a function of implementing an appropriate viscosity required for 3D printing by lowering the viscosity of the overall resin composition by mixing with the photocurable water-soluble oligomer having a relatively high viscosity, and as an example, ACMO (Acryloyl morpholine), DMAA (N,N-Dimethyl acrylamide), HEAA (N-(2-Hydroxyethyl)acrylamide) containing a nitrogen bond (-N-), MAANa (Sodium Methacrylate) containing a sodium salt, or -SO3 - M + 3-Sulfopropyl acrylate potassium salt, etc. can be used.

[0050] Here, in the case of ACMO, since it has a high temperature value of 145℃ or higher in terms of glass transition temperature (Tg), it can be particularly usefully used in a resin composition for producing a melting mold that requires use at high temperatures.

[0051]

[0052] The water-soluble photocurable resin composition for manufacturing a melt-type casting mold according to the present invention may further include the following composition components in addition to the photocurable water-soluble oligomer, photocurable water-soluble monomer, and photoinitiator described above.

[0053]

[0054] (4) Water-soluble resin

[0055] In order to be easily dissolved in neutral to basic aqueous solutions, the backbone structure may contain nitrogen bonds (-N-) or ether bonds (-O-), or other bonds such as -OH, -COOH, -NH-, -NH2, -N-CO-, M-OH (M means metal), and sodium (Na). + )salt, -SO3 - M + (where M is H, Na or K) and N+ X - (wherein, X is OH, Cl or BF4), etc., but is a water-soluble resin having a structure that does not have any photo-reactive group such as the aforementioned epoxy or (meth)acrylate reactive group, and can be added to increase the hardness and strength of the cured resin and improve the processability of the casting mold.

[0056] Examples include polyvinylalcohol (PVA) or polyglycerin containing -OH, polyacrylamide (PAAM) containing -NH2, or polyvinylpyrrolidone (PVP) containing -N-, and also polyvinylamine hydrochloride (PVH) containing chlorine (-Cl), polymaleic acid containing -COOH, or polystyrenesulfonic acid containing sodium salt.

[0057] The water-soluble resin without the above-described photoreactor can be added in the range of 5 to 40 wt% of the total weight of the resin composition, but it is preferably added in the range of 5 to 15 wt%.

[0058]

[0059] (5) Water-soluble filler

[0060] As a water-soluble powder, it dissolves well in water, but does not dissolve at all in a photocurable oligomer or monomer, and is maintained in a powder-mixed state in a photocurable resin composition. During the curing process of the resin by light, it is added to suppress shrinkage of the resin due to photocuring and effectively shorten the time for the casting mold to dissolve in an aqueous solution.

[0061] Examples of water-soluble fillers that can be added to the resin composition of the present invention include sugar, salt, or potassium chloride (KCl), boric acid (H3BO3), potassium carbonate (KHCO3), sodium carbonate (NaHCO3), ammonium carbonate (NH4HCO3), calcium chloride (CaCl2), etc., and the type of water-soluble filler to be added can be appropriately selected according to the properties of the aqueous solution that will dissolve the casting mold, and at this time, the content of the filler is adjusted according to the pH concentration and temperature of the aqueous solution for dissolution and the structure of the casting mold.

[0062] In general, water-soluble fillers can be added up to a maximum of 50 wt% of the total weight of the resin composition, but it is preferable to add them in the range of 10 to 20 wt%.

[0063]

[0064] (6) Pigment

[0065] In the 3D printing process using light irradiation, the light of the 2D image irradiated for each layer leaks into the surrounding resin, hardening the resin around the 2D image to be printed, thereby preventing the occurrence of burrs or holes in the printed product or deformation of the printed product, thereby improving the precision of 3D printing.

[0066] Common pigments used in photocurable paints can be used. Colored pigments are primarily used for light absorption, but transparent pigments can also be used. Black carbon is ideal.

[0067] The pigment added to the resin composition can be appropriately selected depending on the type and amount of light source used for 3D printing, and is usually added in the range of 0.01 to 2.00 wt% of the total weight of the resin composition, and preferably, it is good to add in the range of 0.02 to 0.10 wt%.

[0068]

[0069] (6) Other additives

[0070] In addition, the water-soluble photocurable resin composition according to the present invention may include various other additives, such as a defoaming agent for removing bubbles, a dispersing agent for improving the dispersing ability of the water-soluble filler added, a polymerization inhibitor for preventing the resin composition from hardening during storage, and a silane additive for improving the heat resistance of the resin composition, and may generally be added in a range of 0.5 to 2.0 wt% of the total weight of the resin composition.

[0071]

[0072] The water-soluble photocurable resin composition for manufacturing a melt-type casting mold according to the present invention implements the following characteristic properties through a combination of the composition components described above.

[0073] ▶ Photocurable: 1.0 to 10.0 mJ / cm in the wavelength range of 200 to 900 nm 2 Curable by light irradiation at high energy levels.

[0074] ▶ Viscosity: Viscosity that allows liquid application in the range of 100 cPs to 20,000 cPs, so that it can be effectively used in top-down or bottom-up 3D printing using light irradiation.

[0075] ▶ Solubility: When immersed in a neutral or alkaline aqueous solution with a pH of 6.0 or higher, the solubility is such that a 5mm cubic 3D printed material can completely dissolve or swell within 3 hours.

[0076] ▶ Washability: After curing, it does not dissolve in common organic solvents such as alcohol, acetone, or ketones, so washing with organic solvents is possible after printing.

[0077] ▶ Hardness after curing: After curing, secant modulus of 500 MPa or more, elongation at break of 4% or more.

[0078] ▶ Heat resistance: Heat Deflection Temperature (HDT) 70℃ or higher, preferably 150℃ or higher.

[0079]

[0080] Example 1. Water-soluble photocurable resin composition #1: Resin composition A

[0081] A water-soluble photo-curable resin composition A capable of 3D printing through photo-curing and easily soluble in a neutral or basic aqueous solution after curing, comprising 30.0 wt% of SWA8083, a photo-curable water-soluble oligomer containing a plurality of ether bonds (-O-) and a plurality of hydroxyl groups (-OH), 56.0 wt% of a photo-curable water-soluble monomer HEAA [N-(2-Hydroxyethyl)acrylamide] containing -NH and -OH, 10.0 wt% of a photo-curable monomer HEMA [2-Hydroxyethyl Methacrylate] containing -OH, 3.35 wt% of TPO [2,4,6-trimethylbenzoyldiphenyl phosphine oxide] added as a photo-initiator, and 0.15 wt% of BKP, a carbon-dispersed black pigment of Ilsam Co., Ltd., and 0.5 wt% of BYK-011 as an antifoaming agent as other additives. It was mixed.

[0082] The resin composition A compounded in the above-described manner has a viscosity of 520 cPs at room temperature and 0.2 mW / cm 2 A 50 μm thick film was confirmed to be cured in 1.5 seconds in an LCD-based 3D printer illuminated by a light intensity of . After curing, the secant modulus (1.0% elongation) of the cured film was measured to be 1,200 MPa and the elongation at break was 1.5%.

[0083]

[0084] <Solubility test of the cured resin composition after curing>

[0085] Using the above resin composition A, a cube measuring 5 mm x 5 mm x 5 mm was manufactured through 3D printing using a layer-stacking method with a thickness of 50 μm using an LCD-based 3D printer, and the uncured resin remaining on the surface of the manufactured cube was removed through acetone washing, and then cured at 20 mW / cm in a post-curing machine. 2 A 10-minute post-curing process was performed using light irradiation of the amount of light.

[0086] Afterwards, the printed cube specimens were immersed in NaOH aqueous solutions of different concentrations and temperatures, and the change in solubility over time was observed, and the results are summarized in [Table 1].

[0087]

[0088] Test Number NaOH Concentration (wt%) Aqueous Solution Temperature (℃) After 6 hours After 12 hours After 24 hours SB01025--Swelling SB02425--Completely dissolved SB031025-Completely dissolved SB041050-Completely dissolved SB051080Completely dissolved SB062025-Completely dissolved

[0089] [Solubility of cubes according to concentration and temperature of NaOH aqueous solution]

[0090]

[0091] As confirmed in [Table 1], it can be confirmed that the cube specimen printed using the water-soluble photocurable resin composition according to the present invention as a material easily dissolves in a neutral to basic aqueous solution, and although the dissolution rate increases as the concentration of NaOH increases, there was no significant change in the dissolution rate when the concentration of NaOH exceeded 10 wt%. In addition, when looking at a comparative example in a 10 wt% NaOH solution, it can be confirmed that the dissolution rate increases as the temperature of the aqueous solution increases.

[0092]

[0093] Example 2. Water-soluble photocurable resin composition #2: Resin compositions B1 to B6

[0094] A combination of 30.0 wt% of SWA8083, a photocurable water-soluble oligomer containing a plurality of ether bonds (-O-) and a plurality of hydroxyl groups (-OH), 56.0 wt% of HEAA [N-(2-Hydroxyethyl)acrylamide], a photocurable water-soluble monomer containing -NH and -OH, 5.0 wt% of HEMA [2-Hydroxyethyl Methacrylate], a photocurable monomer containing -OH, 3.35 wt% of TPO [2,4,6-trimethylbenzoyldiphenyl phosphine oxide] added as a photoinitiator, and 0.15 wt% of BKP, a carbon-dispersed black pigment of Ilsam Co., Ltd., and 0.5 wt% of BYK-011 as a defoaming agent, and PVA (Polyvinylalcohol, molecular weight 100,000), a non-reactive water-soluble resin not containing a photoreactive group, as well as other additives 10,000 g / mole) was mixed at 5.0 wt% to form a resin composition B1 for compatibility testing of a non-reactive water-soluble resin in a resin composition.

[0095] Next, resin compositions B2 and B3 were compounded by reducing the content of HEAA to 51.0 wt% and 41.0 wt%, respectively, and increasing the content of PVA to 10.0 wt% and 20.0 wt%, respectively.

[0096] At the same time, under the same conditions, PVA was replaced with another non-reactive water-soluble resin, polyglycerin (PG, molecular weight 2,000 g / mole), and resin compositions B4 to B6 having PG contents of 5.0 wt%, 10.0 wt%, and 20.0 wt%, respectively, were compounded.

[0097] The resin compositions B1 to B6 mixed in the above-described mixing ratio were placed in a water tank and stirred well, and then the separation and precipitation of non-reactive water-soluble resin was confirmed at room temperature.

[0098]

[0099] Resin composition SWA8083 HEAAHEMAPVAPG Photoinitiator / Other additives Separation / precipitation B130.056.05.05.04.0 Transparent B230.051.05.010.04.0 Transparent B330.041.05.020.04.0 Separation / precipitation B430.056.05.05.04.0 Transparent B530.051.05.010.04.0 Transparent B630.041.05.020.04.0 Separation / precipitation

[0100] [Compatibility test according to non-reactive water-soluble resin content (unit: wt%)]

[0101]

[0102] As shown in [Table 2], both PVA and PG, which are non-reactive water-soluble resins, were found to dissolve well in the resin composition when mixed at 5.0 wt% and 10.0 wt%, respectively. However, when the content increased to 20.0 wt%, some of them were separated out without being mixed into the resin composition. As a result of repeated experiments performed while changing the content of water-soluble resin, no separation was observed in both PVA and PG in the range of 5.0 to 15.0 wt%.

[0103]

[0104] <Post-curing physical properties and curing speed test of resin composition>

[0105] Among the resin compositions B1 to B6 described above, B1, B2, B4 and B5, which have been confirmed to have compatibility with water-soluble resins, were used as printing materials, and 0.2 mW / cm 2 The time required for a 50 μm-thick film to fully cure in a high-capacity LCD-based 3D printer was measured. Subsequently, the secant modulus and elongation at break of the fully cured film were measured.

[0106]

[0107] Resin composition viscosity (cPs) Curing time (sec.) Secant modulus (MPa) Elongation at break (%) Drop test CNC processability B17 20 1.51, 159 2.2 Unbreakable B2 2 5 6 0 2.2 9 5 0 8.9 Good Possible B4 5 8 0 1.59 20 3.2 Unbreakable B5 8 20 2.4 5 6 0 9.8 Good Possible

[0108] [Resin compositions containing non-reactive water-soluble resins and physical properties testing of printed materials]

[0109]

[0110] As confirmed in [Table 3], in the case of resin composition B1 containing 5.0 wt% of non-reactive water-soluble resin, the curing time is 1.5 seconds, which is almost the same curing speed as that of resin composition A not containing non-reactive water-soluble resin disclosed in Example 1 above. However, in the case of resin composition B2 containing 10.0 wt% of non-reactive water-soluble resin, the curing time increases to 2.2 seconds, which confirms that as the content of non-reactive water-soluble resin increases, the curing speed becomes slower, and as a larger amount of light energy is required, the time required for the 3D printing process for printing the output increases.

[0111] When examining the properties of the cured film, it can be confirmed that although the secant modulus of the cured film decreases as the content of the non-reactive water-soluble resin increases, conversely, the elongation at break of the cured film improves as the content of the non-reactive water-soluble resin increases. In other words, compared to the elongation at break of 1.5% in the film manufactured using resin composition A that does not contain the non-reactive water-soluble resin in Example 1, the elongation at break of the film manufactured using B1 to B5 containing the non-reactive water-soluble resin increased to 2.2% to 9.8%.

[0112] Next, a cube print of the same material measuring 10 mm x 10 mm x 10 mm was printed, and the breakage was checked by free dropping from a height of 1 m, and the breakage or chipping was checked during CNC surface machining. To pass these tests, a breaking elongation of at least 4.0% or more is required, and resin compositions B2 and B5 containing 10.0% of PVA or PG each show a breaking elongation sufficient to pass this.

[0113]

[0114] <Solubility Test of Cured 3D Printing Outputs>

[0115] Using the resin compositions B1, B2, B4 and B5 used in the previous property test and the resin composition A disclosed in Example 1, a cube measuring 5 mm x 5 mm x 5 mm was manufactured through 3D printing in a layer-lamination method with a thickness of 50 μm using an LCD-based 3D printer, and the uncured resin remaining on the surface of the manufactured cube was removed through acetone washing, and then cured in a post-curing machine at 20 mW / cm 2 A 10-minute post-curing process was performed using light irradiation of the amount of light.

[0116] Afterwards, the printed cube specimen was immersed in a 10 wt% NaOH aqueous solution, and the change in solubility over time at room temperature was observed.

[0117]

[0118] Resin composition Non-reactive water-soluble resin content (wt%) After 3 hours After 6 hours After 12 hours A0.0 Completely dissolved B15.0 (PVA) 60% dissolved Completely dissolved - B2 10.0 (PVA) Completely dissolved - B4 5.0 (PG) 80% dissolved Completely dissolved - B5 10.0 (PG) Completely dissolved -

[0119] [Solubility of resin composition according to non-reactive water-soluble resin content]

[0120]

[0121] As confirmed in [Table 4], when a non-reactive water-soluble resin is additionally mixed into the photocurable water-soluble resin composition according to the present invention, it can be confirmed that the time for complete dissolution of the manufactured cubes is shortened as the content of the non-reactive water-soluble resin added increases, and in particular, in the case of B2 and B4, when about 10% of the non-reactive water-soluble resin is contained, complete dissolution was found to occur within 3 hours.

[0122] In addition, although a relatively fast dissolution rate is shown in a resin composition containing PG having a relatively low molecular weight of 2,000 g / mole compared to PVA having a molecular weight of 10,000 g / mole, on the other hand, as shown in the above property comparison, the lower the molecular weight of the added non-reactive water-soluble resin, the relatively weaker some properties of the printed matter, such as the secant modulus, are; therefore, it is desirable to selectively apply an appropriate type of non-reactive water-soluble resin depending on the purpose and characteristics of the casting mold to be manufactured.

[0123]

[0124] Example 3. Water-soluble photocurable resin composition #3: Resin composition C1 to C6

[0125] A photocurable water-soluble oligomer containing 30.0 wt% of SWA8083, a photocurable water-soluble monomer containing a plurality of ether bonds (-O-) and a plurality of hydroxyl groups (-OH), 46.0 wt% of a photocurable water-soluble monomer HEAA [N-(2-Hydroxyethyl)acrylamide] containing -NH and -OH, 5.0 wt% of a photocurable monomer HEMA [2-Hydroxyethyl Methacrylate] containing -OH, 3.35 wt% of TPO [2,4,6-trimethylbenzoyldiphenyl phosphine oxide] added as a photoinitiator, 10.0 wt% of a non-reactive water-soluble resin PVA, and other additives, a combination of 0.15 wt% of BKP, a carbon-dispersed black pigment of Ilsam Co., Ltd., and 0.5 wt% of BYK-011 as a defoaming agent, and 5 μm powder of sugar blended as a water-soluble filler. 5.0 wt% of the photocurable water-soluble resin composition C1 was mixed.

[0126] Next, resin compositions C2 and C3 were compounded by reducing the content of HEAA to 41.0 wt% and 36.0 wt%, respectively, and increasing the content of sugar accordingly to 10.0 wt% and 15.0 wt%, respectively.

[0127] At the same time, under the same conditions, the 5 μm powder of sugar mixed as a water-soluble filler was replaced with 5 μm powder of calcium chloride, and resin compositions C4 to C6 having calcium chloride contents of 5.0 wt%, 10.0 wt%, and 15.0 wt%, respectively, were mixed.

[0128] At this time, the water-soluble filler applied to the present invention has the characteristic of being well soluble in water but not soluble at all in the photocurable water-soluble resin composition, so the powder size of the water-soluble filler to be mixed must be carefully selected.

[0129] In this example, both sugar and calcium chloride were used as powders having an average particle size (d50) of 5 μm and a maximum particle size (d90) of 8 μm or less, and the resin compositions C1 to C6 mixed in the mixing ratio described above were placed in a water tank and stirred well, and it was confirmed whether the water-soluble filler powder was separated from the resin composition and deposited at the bottom at room temperature.

[0130]

[0131] Resin composition SWA8083 HEAAHEMAPVA Sugar Calcium chloride Light initiator / other additives Filler Separation C130.04 6.05.0 10.05.0-4.0 None C230.04 1.05.0 10.010.0-4.0 None C330.036.05.0 10.015.0-4.0 None C430.04 6.05.0 10.0-5.04.0 None C530.04 1.05.0 10.0-10.04.0 None C630.036.05.0 10.0-15.04.0 None

[0132] [Test for filler separation in resin compositions with added water-soluble filler (unit: wt%)]

[0133]

[0134] As confirmed in [Table 5], in the case of a water-soluble filler with an average particle size of 5 μm, no separation from the resin composition was observed even after 24 hours after mixing. However, in a similar test, when a water-soluble filler with an average particle size of 10 μm was used, it was confirmed that a large amount of filler was separated from the resin composition and settled on the bottom of the tank within about 30 minutes. Therefore, it can be confirmed that when mixing a water-soluble filler into the photocurable water-soluble resin composition according to the present invention, it is preferable to use a powder with an average particle size of at least 5 μm or less.

[0135]

[0136] <Post-curing physical properties and curing speed test of resin composition>

[0137] Using the resin compositions C1 to C6 described above as printing materials, 0.2 mW / cm2 The time required for a 50 μm-thick film to fully cure in a high-capacity LCD-based 3D printer was measured. Subsequently, the secant modulus and elongation at break of the fully cured film were measured.

[0138]

[0139] Resin composition viscosity (cPs) Curing time (sec.) Secant Modulus (MPa) Elongation at break (%) Drop test CNC processability C12, 7402.51, 1508.7 Good possible C22, 8603.21, 2208.2 Good possible C33, 2503.81, 4408.0 Good possible C42, 7202.61, 2408.6 Good possible C52, 8103.21, 3308.2 Good possible C63, 1403.91, 5507.9 Good possible

[0140] [Property Test of Resin Compositions and Outputs Containing Water-Soluble Fillers]

[0141]

[0142] As can be seen in [Table 6], as the content of water-soluble filler mixed into the resin composition increases, a greater amount of light energy is required for curing the resin composition, and thus the time required for the 3D printing process for printing the output is gradually increasing.

[0143] Looking at the properties of the cured film, the secant modulus of the cured film increases as the content of the water-soluble filler increases, and conversely, the elongation at break decreases slightly. However, it still shows an excellent elongation at break of over 7.9%, and it was confirmed that it maintains a high elongation at break sufficient to pass the drop test and CNC machinability test to check for breakage through free fall.

[0144]

[0145] <Solubility Test of Cured 3D Printing Outputs>

[0146] Using the resin compositions C1 to C6 used in the above physical property test and the resin composition B2 disclosed in the above Example 2, which does not contain a water-soluble filler, a cube of 5 mm x 5 mm x 5 mm in size was manufactured through 3D printing in a layer-lamination method with a thickness of 50 μm using an LCD-based 3D printer, and the uncured resin remaining on the surface of the manufactured cube was removed through acetone washing, and then cured in a post-curing machine at 20 mW / cm 2 A 10-minute post-curing process was performed using light irradiation of the amount of light.

[0147] Afterwards, the printed cube specimen was immersed in a 10 wt% NaOH aqueous solution, and the change in solubility over time at room temperature was observed.

[0148]

[0149] Resin composition Water-soluble filler content (wt%) After 1 hour After 3 hours B20.0 Crack occurrence Completely dissolved C15.0 (sugar) Crack occurrence Completely dissolved C2 10.0 (sugar) 60% dissolved Completely dissolved C3 15.0 (sugar) Completely dissolved - C4 5.0 (calcium chloride) 60% dissolved Completely dissolved C5 10.0 (calcium chloride) Completely dissolved - C6 15.0 (calcium chloride) Completely dissolved -

[0150] [Solubility of resin composition according to water-soluble filler content]

[0151]

[0152] As confirmed in [Table 7], when a water-soluble filler is additionally mixed into the photocurable water-soluble resin composition according to the present invention, it can be confirmed that the time for the manufactured cubes to be completely dissolved is shortened as the content of the water-soluble filler to be mixed increases, and in particular, when calcium chloride is used as a filler, it is shown to show a relatively faster dissolution rate compared to when sugar is used. Through this, it can be predicted that not only the solubility of the water-soluble filler included in the resin composition in water but also the crystal structure of the filler powder affects the solubility of the resin composition.

[0153]

[0154] As described above, the water-soluble photocurable resin composition according to the present invention can be widely used in SLA-type 3D printing using various light sources due to its low viscosity and fast photocuring speed characteristics that enable liquid application, and at the same time, it has the characteristic of easily dissolving in a neutral or basic aqueous solution, so that a casting mold for manufacturing a 3D structure through a photocuring-type 3D printing process is formed, and after the product injected into the mold is solidified, it is dissolved in the aqueous solution through a simple process of being immersed in water or an basic aqueous solution for a certain period of time, and thus can be easily separated without concern for damage to the structure or surface of the 3D structure solidified in the mold, so that it can be usefully used in the production of various 3D structures including complex shapes or cavity structures.

[0155]

[0156] Hereinafter, a method for manufacturing a 3D structure of the present invention, which is performed using a melt-casting mold manufactured using the above-described water-soluble photocurable resin composition as a material, will be described in more detail with reference to the attached drawings.

[0157]

[0158] FIG. 1 is a flowchart briefly showing the process of performing a method for manufacturing a 3D structure using a casting mold made of a water-soluble photocurable resin according to the present invention. As shown in FIG. 1, in the present invention, a water-soluble photocurable resin that satisfies the physical property requirements discussed above is used as a printing material, and a casting mold for manufacturing a 3D structure for casting a 3D product to be finally produced is first manufactured (S100) through a 3D printing process using a photocuring method.

[0159] At this time, a representative 3D printing method applied to the production of a casting mold for manufacturing a 3D structure of the present invention includes the SLA (Stereolithography) method, and various light sources such as LCD, DLP, or Laser can be utilized.

[0160] The above-described SLA method 3D printing technology is already widely known and used in the technical field, and a detailed description thereof will be omitted in this specification. In the method for manufacturing a 3D structure according to the present invention, by applying the photocuring method 3D printing technology as described above, even if the casting mold is formed of a relatively very complex shape or structure, as briefly described above, a casting mold of a desired structure can be easily manufactured through a single simple 3D printing process without complicated prior preparation such as separate partial design or separate manufacturing and assembly of each part, thereby very effectively shortening the existing mold manufacturing process for producing 3D products and also significantly reducing the mold manufacturing cost.

[0161]

[0162] At this time, when manufacturing a casting mold for casting a desired 3D product through 3D printing using the photocuring properties of the resin composition as described above, as shown in FIG. 2, an injection port (runner, 10) into which a casting material is injected is formed on one side of the manufacturing casting mold, and an exhaust port (riser, 20) through which air within the mold is discharged is formed on the other side of the mold.

[0163] FIG. 2 is a drawing exemplarily showing a casting mold manufactured to produce a buckle according to one embodiment of the present invention. As shown in FIG. 2, an injection port (10) for injecting a casting material is formed on one side of the upper portion of the casting mold, and an exhaust port (20) for discharging air within the mold is formed on the other side.

[0164] In addition, when manufacturing a casting mold through 3D printing using the photocuring method described above, it is recommended not to form the mold wall thicker than necessary.

[0165] As will be explained again below, in the present invention, after the casting material injected into the mold has hardened, the mold is dissolved by immersing the mold in water or an alkaline aqueous solution to separate the mold from the produced product. Therefore, the thicker the casting mold, the more time is required to dissolve the mold, which lowers production efficiency.

[0166] Therefore, the thickness of the casting mold manufactured according to the present invention is sufficient if it is a thickness that can maintain structural stability until the casting material injected into the mold is hardened, and it is preferable to set it to an appropriate thickness that is suitable for the weight, temperature, and / or pressure of the casting material injected into the mold.

[0167]

[0168] Next, when a casting mold is manufactured according to the above-described process, a liquid casting material is injected into the mold through an injection port (10) formed in the mold (S200), and air bubbles remaining inside the mold are removed through an exhaust port (20) using a vacuum chamber (S300).

[0169] Afterwards, the casting material injected into the mold through the above-described process is subjected to a hardening step (S400). The hardening process applied at this time can be appropriately selected depending on the characteristics of the casting material injected into the mold.

[0170] That is, in the case of thermoplastic resins such as acrylic resins or lost wax used for lost wax casting, the molten casting material is injected into a mold preheated to a certain temperature and then cooled at room temperature, or in the case of materials that harden through a chemical reaction such as urethane resins or epoxy resins, a liquid resin in which a main component and a hardener component are mixed is injected into the mold, and after removing air bubbles contained in the liquid resin through a vacuum chamber, the material injected into the mold can be completely hardened through a mutual reaction in a chamber in which a high-pressure environment is created so that additional air bubble generation can be suppressed.

[0171]

[0172] After the material injected into the mold has completely hardened, the casting mold with the hardened material injected inside is immersed in water or an alkaline aqueous solution to dissolve the mold (S500) and remove it, and then the product is produced through the washing and drying (S600) steps.

[0173] Here, the solution used to dissolve the mold may be neutral water as is, but if an alkaline aqueous solution is used, the dissolution rate of the mold can be further improved, and it is preferable to use a neutral or basic aqueous solution in the range of pH 6 to pH 12.

[0174] At this time, although the higher the temperature of the neutral to basic aqueous solution used in the dissolution process of the mold, the faster the dissolution can be achieved, an excessively high temperature can affect not only the mold but also the product contained within the mold, so the temperature should be appropriately selected in consideration of the mold material and the product material contained within the mold, but it is generally preferable to adjust it to a range of 20°C to 60°C.

[0175] Additionally, it goes without saying that the dissolution rate can be further improved by causing fluidity in the aqueous solution, such as by stirring the aqueous solution in which the mold is immersed.

[0176]

[0177] As briefly explained above, the 3D structure produced through the above-described melt casting mold production and mold casting using the produced casting mold can be widely and diversely utilized, not only for acrylic PMMA resin products, which have been most widely used as materials for producing 3D structures using the mold casting method in the past, but also for epoxy and / or urethane resin products that are cured through chemical reactions, and for producing silicone structures using reactive silicone.

[0178] In particular, the method for manufacturing a 3D structure using a casting mold made of a water-soluble photocurable resin according to the present invention can be very usefully utilized in manufacturing a wax structure for lost wax casting. Since the temperature of the wax melt injected into the mold for casting is not that high, typically around 120°C, and no separate high pressure is required during the casting process, the thickness of the casting mold for the water-soluble resin composition material manufactured for casting the wax structure can be reduced to around 3 mm, so that not only can the manufacturing time of the casting mold be significantly shortened, but also, as the volume of the casting mold is reduced in this way, the time required to melt the casting mold surrounding the wax structure after the structure is cured can be significantly shortened, so that the overall manufacturing efficiency of the wax structure can be greatly improved.

[0179]

[0180] FIG. 3 is a drawing showing an example of a result of manufacturing a product with a complex buckle structure, which is difficult to manufacture using a conventional injection molding method, using a lost wax material according to a method for manufacturing a 3D structure using a casting mold made of a water-soluble photocurable resin according to the present invention.

[0181] As can be seen from the drawing, the buckle illustrated in FIG. 3 has a complex structure including a hollow portion and a concave portion, and thus, if it were to be manufactured using a conventional injection molding method, a complex preparatory process such as separate manufacturing and assembly of the mold would be required, and not only would it not be easy to separate the product from the mold after casting the product, but in order to solve this problem, if the product is divided into multiple parts, casted, and then assembled, the time and cost required for the manufacturing process would increase, and at the same time, there would be limitations in neatly processing the assembly portion of the final product. However, by applying a method for manufacturing a 3D structure using a casting mold made of a water-soluble photocurable resin according to the present invention, it can be confirmed that a buckle product with a complex structure can be accurately implemented and manufactured with only one simple casting process.

[0182]

[0183] Although the present invention has been described above through representative embodiments of the present invention, the embodiments of the present invention described as examples only show examples of preferred embodiments of the present invention, and the present invention is not limited thereto, and the protection scope of the present invention is limited by the matters described in the claims that will be described later. In addition, it is obvious that a person having ordinary skill in the technical field to which the present invention pertains can implement various modifications without changing the gist of the present invention claimed in the claims, and such modifications or improvements are within the protection scope of the present invention as long as the scope is within the scope of matters obvious to a person having ordinary skill in the technical field to which the present invention pertains.

[0184]

[0185] The water-soluble photocurable resin composition proposed in the present invention can be widely used in SLA-type 3D printing using various light sources due to its low viscosity and fast photocuring speed characteristics that enable liquid application, and at the same time, it has the characteristic of easily dissolving in neutral or basic aqueous solutions, so that a casting mold for manufacturing a 3D structure through a photocuring-type 3D printing process is formed, and after the product injected into the mold is solidified, it is dissolved in the aqueous solution through a simple process of being immersed in water or an basic aqueous solution for a certain period of time, and can be easily separated without concern for damage to the structure or surface of the 3D structure solidified in the mold, so that it can be usefully used in the production of various 3D structures including complex shapes or cavity structures.

[0186] In addition, the method for manufacturing a 3D structure using a casting mold made of a water-soluble photocurable resin according to the present invention supports relatively easy manufacturing of a casting mold having a complex shape or structure by manufacturing a casting mold for manufacturing a 3D structure through a photocuring 3D printing technique, and at the same time, the product manufactured through a simple process of immersing and dissolving the mold in a neutral or basic aqueous solution can be easily separated from the mold without damage, and through the mold casting method of basically borrowing the product manufacturing method, various existing materials, such as wax or polymer oligomer, which have been applied to the existing mold casting method product production, can be widely utilized in the production of products.

Claims

1. A method for manufacturing a 3D structure using a casting mold, A step of manufacturing a casting mold for manufacturing a 3D structure for casting a 3D structure through a photocuring 3D printing process using a water-soluble photocurable resin as a printing material; A step of injecting a liquid casting material into a mold to form a 3D structure; A step of removing air bubbles remaining inside the mold using a vacuum chamber; A step of hardening the casting material injected into the mold; and A step of immersing the casting mold in a hardened state of the injected material in an aqueous solution to dissolve and remove the mold; A method for manufacturing a 3D structure using a casting mold made of a water-soluble photocurable resin, characterized in that it comprises:

2. In paragraph 1, After the step of immersing the casting mold in an aqueous solution to dissolve and remove the mold, A method for manufacturing a 3D structure using a casting mold made of a water-soluble photocurable resin, characterized in that the step of additionally washing and drying the 3D structure separated from the mold is performed.

3. In paragraph 1, In the above water-soluble photocurable resin, i) having at least two epoxy or acrylate reactive groups, and containing nitrogen (N) in the backbone structure, or -OH, -COOH, -NH-, -NH2, -N-CO-, M-OH (M means metal), sodium (Na) + )salt, -SO3 - M + (where M is H, Na or K) and N + X - (wherein, X is an oligomer comprising at least one of OH, Cl or BF4); ii) having at least one epoxy or acrylate reactive group, and containing nitrogen (N) in the structural component, or -OH, -COOH, -NH-, -NH2, -N-CO-, M-OH (M means metal), sodium (Na) + )salt, -SO3 - M + (where M is H, Na or K) and N + X - (wherein, X is a monomer comprising at least one of OH, Cl or BF4); and iii) Photoinitiator for photocuring reaction; A method for manufacturing a 3D structure using a casting mold made of a water-soluble photocurable resin characterized by including:

4. In paragraph 3, In the above water-soluble photocurable resin, A method for manufacturing a 3D structure using a casting mold made of a water-soluble photocurable resin, characterized in that a water-soluble resin having no photocurable reaction group is additionally included in an amount of 5 wt% to 15 wt%.

5. In paragraph 3, In the above water-soluble photocurable resin, A method for manufacturing a 3D structure using a casting mold made of a water-soluble photocurable resin characterized in that it contains at least one functional additive.

6. In paragraph 5, The above functional additives include: A method for manufacturing a 3D structure using a casting mold made of a water-soluble photocurable resin characterized by including a functional pigment for increasing the precision of 3D printing or a carbon nanotube or inorganic additive for increasing the heat transfer coefficient of a printed casting mold.

7. In paragraph 3, The above water-soluble photocurable resin is, A method for manufacturing a 3D structure using a casting mold made of a water-soluble photocurable resin characterized by having a viscosity in the range of 100 cPs to 20,000 cPs.

8. In paragraph 6, The above water-soluble photocurable resin is, A method for manufacturing a 3D structure using a casting mold made of a water-soluble photocurable resin, characterized in that the photocurable resin has a heat deflection temperature (HDT) of at least 70°C after curing.

9. In paragraph 1, In the step of manufacturing a casting mold for manufacturing a 3D structure through the above photocuring 3D printing process, A method for manufacturing a 3D structure using a casting mold made of a water-soluble photocurable resin, characterized in that a 3D printing method using stereolithography (SLA) is applied.

10. In paragraph 1, In the step of manufacturing a casting mold for manufacturing a 3D structure through the above photocuring 3D printing process, A method for manufacturing a 3D structure using a casting mold made of a water-soluble photocurable resin, characterized in that an injection port is formed on one side of the casting mold being manufactured, into which a casting material is injected, and an exhaust port is formed on the other side of the mold, through which air within the mold is discharged.

11. In paragraph 1, In the step of manufacturing a casting mold for manufacturing a 3D structure through the above photocuring 3D printing process, A method for manufacturing a 3D structure using a casting mold made of a water-soluble photocurable resin, characterized in that the thickness of the casting mold to be manufactured is determined by considering the weight, temperature, and pressure of the casting material injected into the casting mold.

12. In paragraph 1, The step of hardening the casting material injected into the above casting mold is: A method for manufacturing a 3D structure using a casting mold made of a water-soluble photocurable resin, characterized in that the casting is performed in a chamber in which a room temperature environment or a high pressure environment is created.

13. In paragraph 1, The aqueous solution used in the step of dissolving and removing the above casting mold is: A method for manufacturing a 3D structure using a casting mold made of a water-soluble photocurable resin characterized by being a neutral or basic aqueous solution having a pH range of 6 to 12.

14. In paragraph 13, The temperature of the above aqueous solution is A method for manufacturing a 3D structure using a casting mold made of a water-soluble photocurable resin characterized in that the temperature is maintained in the range of 20℃ to 60℃.

15. In paragraph 1, In the step of dissolving and removing the mold by immersing the casting mold in an aqueous solution, A method for manufacturing a 3D structure using a casting mold made of a water-soluble photocurable resin, characterized in that the casting mold generates flow in an aqueous solution in which the casting mold is immersed.

16. Contains at least two epoxy or (meth)acrylate reactive groups for photocuring reaction, and has a backbone structure containing nitrogen bond (-N-), ether bond (-O-), -OH, -COOH, -NH-, -NH2, -N-CO-, M-OH (M means metal), sodium (Na) + )salt, -SO3 - M + (where M is H, Na or K) or N + X - (wherein, X is OH, Cl or BF4) 10 to 50 wt% of a photocurable water-soluble oligomer comprising at least one of; and Contains one or two epoxy or (meth)acrylate reactive groups for photocuring reaction, and has a backbone structure containing nitrogen bond (-N-), ether bond (-O-), -OH, -COOH, -NH-, -NH2, -N-CO-, M-OH (M means metal), sodium (Na) + )salt, -SO3 - M + (where M is H, Na or K) or N + X - (wherein, X is OH, Cl or BF4) comprising 50 to 90 wt% of a photocurable water-soluble monomer; A photoinitiator added in a range of 1 to 10 wt% based on the total weight of the resin composition in which the photocurable water-soluble oligomer and the photocurable water-soluble monomer are blended; A water-soluble photocurable resin composition characterized by comprising:

17. In paragraph 16, The above photocurable water-soluble monomer is, A water-soluble photocurable resin composition characterized by being one or a combination of two or more of ACMO (Acryloyl morpholine), DMAA (N,N-Dimethyl acrylamide), HEAA (N-(2-Hydroxyethyl)acrylamide), MAANa (Sodium Methacrylate), or 3-Sulfopropyl acrylate potassium salt.

18. In paragraph 16, The above photoinitiator is, Benzophenone derivatives, benzyl ketones, monomeric hydroxyl ketones, polymeric hydroxyl ketones, a-amino ketones, acyl phosphine oxides, metallocenes, benzoin ethers, benzil ketals, a-hydroxyalkylphenones, a-aminoalkylphenones as radical initiators; or Isopropyl thioxanthenones, arylsulphonium salts, and aryl iodonium salts as cationic initiators; A water-soluble photocurable resin composition characterized by comprising at least one of the following.

19. In paragraph 16, Backbone structure contains nitrogen bonds (-N-), ether bonds (-O-), -OH, -COOH, -NH-, -NH2, -N-CO-, M-OH (M represents metal), and sodium (Na). + )salt, -SO3 - M + (where M is H, Na or K) or N + X - A water-soluble photocurable resin composition characterized in that a water-soluble resin having a structure that includes at least one of (wherein, X is OH, Cl or BF4) but does not include any photoreactive group including an epoxy or (meth)acrylate reactive group is additionally included in an amount of 5 to 15 wt% based on the total weight of the resin composition.

20. In paragraph 19, The above water-soluble resin is, A water-soluble photocurable resin composition characterized by being one or a combination of two or more of polyvinylalcohol (PVA), polyglycerin (PG), polyacrylamide (PAAM), polyvinylpyrrolidone (PVP), polyvinylamine hydrochloride (PVH), polymaleic acid, or polystyrenesulfonic acid.

21. In paragraph 19, A water-soluble photocurable resin composition characterized in that a water-soluble filler in the form of a water-soluble powder, which has a property of soluble in water but not soluble at all in a photocurable oligomer or monomer, is additionally included in an amount of 10 to 20 wt% based on the total weight of the resin composition.

22. In paragraph 21, The above water-soluble filler is, A water-soluble photocurable resin composition characterized by comprising one or a combination of two or more of sugar, salt, potassium chloride (KCl), boric acid (H3BO3), potassium carbonate (KHCO3), sodium carbonate (NaHCO3), ammonium carbonate (NH4HCO3), and calcium chloride (CaCl2).

23. In paragraph 21, The above water-soluble filler is, A water-soluble photocurable resin composition characterized in that it is included in the resin composition in the form of a powder having an average particle size of 5 μm or less.

24. In paragraph 16, In the above resin composition, A water-soluble photocurable resin composition characterized in that other additives comprising one or a combination of two or more of a pigment, an antifoaming agent, a dispersing agent, a polymerization inhibitor, and a silane additive are additionally included in an amount of 0.5 to 2.0 wt% based on the total weight of the resin composition.

25. In paragraph 24, A water-soluble photocurable resin composition characterized in that the pigment is black carbon.

26. In paragraph 16, The above water-soluble photocurable resin composition, A water-soluble photocurable resin composition characterized by having a viscosity in the range of 100 to 20,000 cPs.

27. In paragraph 16, The above water-soluble photocurable resin composition, A water-soluble photocurable resin composition characterized in that it has a secant modulus of 500 MPa or more after being cured by light.

28. In paragraph 16, The above water-soluble photocurable resin composition, A water-soluble photocurable resin composition characterized in that it has an elongation at break of 4% or more after being cured by light.

29. In paragraph 16, The above water-soluble photocurable resin composition, A water-soluble photocurable resin composition characterized in that it has a heat deflection temperature (HDT) of 70°C or higher after being cured by light.

Images