Resin composition for three-dimensional object, method for producing three-dimensional object, and three-dimensional object

Abstract

To provide resin compositions for stereo-lithography, etc. that are low in odor, have excellent mechanical properties, and can stably form moldings of desired three-dimensional shapes.SOLUTION: A resin composition for stereo-lithography containing a polyfunctional urethane(meth)acrylate having a molecular weight of 700 or more and 1,300 or less. It is preferred that the multifunctional urethane(meth)acrylate has a polycaprolactone skeleton, and that the molecular weight of the polycaprolactone skeleton is 500 or more and 1,000 or less.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a resin composition for three-dimensional object production, a method for producing a three-dimensional object, and a three-dimensional object. [Background technology]

[0002] In recent years, three-dimensional (3D) printing technology, which uses resin to manufacture three-dimensional objects, has been developing. 3D printers using this type of 3D printing technology allow anyone to easily create three-dimensional objects, so as the prices of 3D printers themselves fall, they are now being used in ordinary households.

[0003] Among the above-mentioned 3D printing technologies, stereolithography uses a liquid photocurable resin composition and is characterized by high finishing precision of the modeled object. As such a photocurable resin composition, for example, an active energy ray-curable resin composition containing a urethane (meth)acrylate having a weight average molecular weight of 3,000 to 30,000 obtained by reacting a polycaprolactone polyol having a number average molecular weight of 300 to 900, an aliphatic or alicyclic diisocyanate, and a hydroxyl group-containing (meth)acrylate has been proposed (see, for example, Patent Document 1). In addition, a film coating composition has been proposed that contains a urethane (meth)acrylate that contains a polycaprolactone polyol having a molecular weight of 800 to 8,000 as a structural unit, and a monofunctional (meth)acrylate that has a glass transition temperature (Tg) of 90°C or higher after curing (see, for example, Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2017-88681 A [Patent Document 2] JP 2000-219821 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, the urethane (meth)acrylates used in the above Patent Documents 1 and 2 have a different structure from the polyfunctional urethane (meth)acrylate used in the present invention, and have a large molecular weight and high viscosity, making them unsuitable for three-dimensional modeling applications. Furthermore, the compositions of the above Patent Documents 1 and 2 contain low-molecular-weight monofunctional monomers that have a strong odor and are highly irritating to the skin, making them unsuitable for use in ordinary households.

[0006] In addition, in the suspended stereolithography, as shown in Figures 1A and 1B, the linear guide 13 rises in the direction of the arrow, and the three-dimensional object 12 is formed in the direction of gravity relative to the modeling surface 11a of the modeling stage 11, so there is a problem that the three-dimensional object 12 is easily broken at its thin-walled portion. Furthermore, because the three-dimensional object is cured in a short time, stress is likely to remain in the three-dimensional object due to curing shrinkage, and the three-dimensional object may break during modeling. In Figures 1A and 1B, 14 is an arm, 15 is a UV light source, 16 is a modeling tank, and 17 is a resin composition for three-dimensional modeling (liquid).

[0007] The present invention aims to solve the above-mentioned problems in the prior art and to achieve the following objects: That is, the present invention relates to a resin composition for three-dimensional modeling, which has low odor and excellent mechanical properties and is capable of stably modeling a three-dimensional object having a desired three-dimensional shape, a method for manufacturing a three-dimensional object, and a three-dimensional object. [Means for solving the problem]

[0008] The means for solving the above problems are as follows. <1> The resin composition for three-dimensional modeling contains a polyfunctional urethane (meth)acrylate having a molecular weight of 700 or more and 1,300 or less. <2> The polyfunctional urethane (meth)acrylate has a polycaprolactone skeleton. <1> The resin composition for three-dimensional object formation described above. <3> The molecular weight of the polycaprolactone skeleton is 500 or more and 1,000 or less. <2> The resin composition for three-dimensional object formation described above. <4> The polyfunctional urethane (meth)acrylate having a polycaprolactone skeleton is represented by either of the following general formula (1) and general formula (2): <2> from <3> 1. The resin composition for three-dimensional object formation according to claim 1 , [ka] In the above general formula (1), R 1 represents a linear alkyl group or a linear alkyl ether group, n1+n2 is an integer of 2 or more and 9 or less, and n3 is an integer of 1 or more. [ka] In the general formula (2), R 2 represents a branched alkyl group, m1+m2+m3 is an integer of 3 or more and 9 or less, and m4 is an integer of 1 or more. <5> The content of the polyfunctional urethane (meth)acrylate is 90% by mass or more based on the total amount of the resin composition for three-dimensional object formation. <1> from <4> 1. The resin composition for three-dimensional object formation according to claim 1 , <6> The photopolymerization initiator is contained in the above. <1> from <5> 1. The resin composition for three-dimensional object formation according to claim 1 , <7> The viscosity at 25°C is 0.1 Pa·s or more and 10 Pa·s or less. <1> from <6> 1. The resin composition for three-dimensional object formation according to claim 1 , <8> A method for producing a three-dimensional object by a stereolithography method, comprising the steps of: The above <1> from <7> and irradiating the resin composition for three-dimensional modeling with active energy rays on the modeling surface of the modeling stage to harden it. <9> A cured layer of the resin composition for three-dimensional object formation is laminated in the direction of gravity on the modeling surface of a modeling stage. <8> 2. A method for producing a three-dimensional object according to claim 1 . <10> The above <1> from <7> The three-dimensional object is obtained by laminating a cured product containing any one of the above resin compositions for three-dimensional object formation. <11> The above is a bait. <10> The three-dimensional object according to the present invention is Effect of the Invention

[0009] According to the present invention, it is possible to solve the above-mentioned problems in the conventional art, achieve the above-mentioned object, and provide a resin composition for three-dimensional modeling, which is low odor, has excellent mechanical properties, and is capable of stably modeling objects of desired three-dimensional shapes, a method for manufacturing a three-dimensional object, and a three-dimensional object. [Brief description of the drawings]

[0010] [Figure 1A] FIG. 1A is a schematic diagram showing an example of a method for producing a three-dimensional object by a suspension-type stereolithography method. [Figure 1B] FIG. 1B is a schematic diagram showing an example of a method for producing a three-dimensional object by the suspended stereolithography method. [Diagram 2] FIG. 2 is a photograph showing examples of three-dimensional objects produced in Examples 1 to 3 and Comparative Example 4. As shown in FIG. [Diagram 3] FIG. 3 is a photograph showing an example of a three-dimensional object produced in Comparative Example 1. As shown in FIG. [Figure 4] FIG. 4 is a photograph showing an example of a three-dimensional object produced in Comparative Example 3. As shown in FIG. [Diagram 5] FIG. 5 is a schematic diagram showing an example of a manufacturing state of a three-dimensional object in Comparative Example 1. As shown in FIG. [Figure 6] FIG. 6 is a schematic diagram showing an example of a manufacturing state of a three-dimensional object in Comparative Example 2. As shown in FIG. [Figure 7] FIG. 7 is a schematic diagram showing an example of an artificial bait. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] (Resin composition for three-dimensional modeling) The resin composition for three-dimensional object formation of the present invention contains a polyfunctional urethane (meth)acrylate having a molecular weight of 700 or more and 1,300 or less, and preferably contains a photopolymerization initiator, and further contains other components as necessary.

[0012] The resin composition for three-dimensional modeling of the present invention contains a polyfunctional urethane (meth)acrylate having a molecular weight of 700 to 1,300, and therefore has a viscosity suitable for three-dimensional modeling, can be cured by heat or light, and the obtained three-dimensional model has excellent mechanical properties (elastic modulus and strength). In addition, the polyfunctional urethane (meth)acrylate having a molecular weight of 700 to 1,300 does not contain a low-molecular-weight monofunctional monomer that has a strong odor and skin irritation, and is therefore considered to have low skin irritation because it has a large molecular weight and does not easily penetrate into the skin. Regarding odor evaluation, if the 5% weight loss temperature in thermogravimetry (TGA) is 300°C or higher, the material is low volatile, and thus odor generation is suppressed, resulting in a low odor. Skin irritation (PII) can be evaluated by applying a patch directly to the skin of a rabbit after shaving the hair. Generally, substances other than acrylates (methacrylates or urethane (meth)acrylates with large molecular weights) are known to have low skin irritation.

[0013] <Multifunctional urethane (meth)acrylate> The polyfunctional urethane (meth)acrylate is not particularly limited as long as it has a urethane structure and has two or more acrylic or methacrylic groups, and can be appropriately selected depending on the purpose.

[0014] The molecular weight of the polyfunctional urethane (meth)acrylate is 700 or more and 1,300 or less, and preferably 750 or more and 1,000 or less. When the molecular weight of the polyfunctional urethane (meth)acrylate is from 700 to 1,300, the resin composition for three-dimensional modeling can have a viscosity suitable for three-dimensional modeling. The molecular weight can be calculated, for example, by using the hydroxyl value OH A , the number of hydroxyl groups in the molecule OH BThe hydroxyl value can be measured according to JIS K 0070:1992. The number of hydroxyl groups in a molecule can be measured by titrating a potassium hydroxide-ethanol solution.

[0015]

number

[0016] The polyfunctional urethane (meth)acrylate preferably has an aliphatic polyester skeleton, an aliphatic polycarbonate skeleton, a polycaprolactone skeleton, or the like as a main skeleton, and particularly preferably has a polycaprolactone skeleton from the viewpoint of imparting flexibility to a three-dimensional object. The molecular weight of the polycaprolactone skeleton is preferably from 500 to 1,000. If the molecular weight of the polycaprolactone skeleton is less than 500, the ratio of the caprolactone skeleton contained in the molecule of the polyfunctional urethane (meth)acrylate having the polycaprolactone skeleton becomes small, and the three-dimensional object cannot be imparted with sufficient flexibility, and may become too hard. The molecular weight of the polycaprolactone skeleton can be measured in the same manner as the molecular weight of the polyfunctional urethane (meth)acrylate.

[0017] The polyfunctional urethane (meth)acrylate having a polycaprolactone skeleton is preferably represented by either of the following general formula (1) or general formula (2).

[0018] [ka] In the above general formula (1), R 1 represents a linear alkyl group or a linear alkyl ether group, n1+n2 is an integer of 2 or more and 9 or less, and n3 is an integer of 1 or more. R 1 represents a linear alkyl group or a linear alkyl ether group, for example, C2 H 2 , C 2 H 2 O.C. 2 H 2 , C 2 H 4 , C 2 H 4 O.C. 2 H 4 , C(CH 3 ) 2 (CH 2 ) 2 etc.

[0019] [ka] In the general formula (2), R 2 represents a branched alkyl group, m1+m2+m3 is an integer of 3 or more and 9 or less, and m4 is an integer of 1 or more. R 2 represents a branched alkyl group, for example, CH 2 CHCH 2 , C.H. 3 C(CH 2 ) 3 , C.H. 3 CH 2 C(CH 2 ) 3 etc.

[0020] The polyfunctional urethane (meth)acrylate having a polycaprolactone skeleton may be appropriately synthesized or a commercially available product. The polyfunctional urethane (meth)acrylate having a polycaprolactone skeleton can be synthesized, for example, by mixing an isocyanate (meth)acrylate (e.g., 2-isocyanate ethyl acrylate) with a polycaprolactone polyol (e.g., polycaprolactone diol or polycaprolactone triol) in an amount of 0.9 equivalents relative to the hydroxyl value of the polycaprolactone polyol, sealing the mixture, and stirring at 60°C for 3 days to synthesize the polyfunctional urethane (meth)acrylate. As the polycaprolactone polyol, commercially available products can be used, and examples of the commercially available products include PLACCEL 205U, PLACCEL 305, and PLACCEL 308 (all manufactured by Daicel Corporation). Examples of the isocyanate (meth)acrylate include Karenz AOI and Karenz MOI (both manufactured by Showa Denko KK).

[0021] The polyfunctional urethane (meth)acrylate having a polycaprolactone skeleton used in the present invention does not use a polycaprolactone polyol, a diisocyanate, and a (meth)acrylate having a hydroxyl group as in the urethane (meth)acrylates of the prior art, but introduces a (meth)acrylic group to the end of the polycaprolactone polyol via a urethane bond using an isocyanate (meth)acrylate, so that the molecular weight of the polyfunctional urethane (meth)acrylate having a polycaprolactone skeleton can be controlled to be 700 or more and 1,300 or less.

[0022] The content of the polyfunctional urethane (meth)acrylate is preferably 90% by mass or more, and more preferably 95% by mass or more, based on the total amount of the resin composition for three-dimensional modeling. When the content of the polyfunctional urethane (meth)acrylate is 90% by mass or more, the composition is substantially free of low molecular weight monofunctional monomers that have a strong odor and skin irritation, and therefore has a low odor and skin irritation and is suitable for three-dimensional modeling.

[0023] <Photopolymerization initiator> As the photopolymerization initiator, a compound that generates radicals upon irradiation with light, particularly ultraviolet light having a wavelength of 220 nm to 500 nm, can be suitably used. Examples of the photopolymerization initiator include acetophenone, 2,2-diethoxyacetophenone, p-dimethylaminoacetophenone, benzophenone, 2-chlorobenzophenone, p,p'-dichlorobenzophenone, p,p-bisdiethylaminobenzophenone, Michler's ketone, benzil, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin-n-propyl ether, benzoin isobutyl ether, benzoin-n-butyl ether, benzyl methyl ketal, thioxanthone, 2-chlorothioxanthone, 2-hydroxy-2-methyl-1-phenylpropanone, 1-(4-isopropylphenyl)2-hydroxy-2-methylpropanone, methylbenzoyl formate, 1-hydroxycyclohexyl phenyl ketone, azobisisobutyronitrile, benzoyl peroxide, and di-tert-butyl peroxide. These may be used alone or in combination of two or more. Furthermore, with the shift to LED light sources (wavelength 405 nm) in photocuring molding devices, photopolymerization initiators that absorb in the visible range are preferred, such as 2,4,6-trimethylbenzoyl-diphenylphosphine oxide and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide.

[0024] The content of the photopolymerization initiator is preferably 1% by mass or more, more preferably 3% by mass or more, based on the total amount of the resin composition for three-dimensional object formation, and is preferably 10% by mass or less.

[0025] <Other ingredients> The other components are not particularly limited and can be appropriately selected depending on the purpose. Examples of the other components include stabilizers, surface treatment agents, colorants, viscosity adjusters, adhesion promoters, antioxidants, antiaging agents, crosslinking accelerators, ultraviolet absorbers, plasticizers, preservatives, dispersants, and pH adjusters.

[0026] The viscosity of the resin composition for three-dimensional object formation of the present invention is preferably from 0.1 Pa·s to 10 Pa·s, more preferably from 0.1 Pa·s to 9 Pa·s, and even more preferably from 0.1 Pa·s to 8 Pa·s at 25° C. When the viscosity is from 0.1 Pa·s to 10 Pa·s at 25° C., the composition can be suitably used in a method for producing a three-dimensional object by stereolithography. The viscosity can be measured, for example, by using a resin composition for three-dimensional modeling using a rotational rheometer (device name: AR-G2, manufactured by TA Instruments) in an environment of 25° C. and at a shear rate of 100 (1 / s).

[0027] The glass transition temperature (Tg) of the cured product of the resin composition for three-dimensional object formation of the present invention is preferably from −60° C. to 50° C., and more preferably from −20° C. to 30° C. When the glass transition temperature is from −60° C. to 50° C., the cured product can have sufficient hardness to maintain its shape. The glass transition temperature can be measured by a dynamic viscoelasticity measuring device (DMA: Dynamic Mechanical Analysis, product name: RSA-3, manufactured by TA Instruments). Specifically, the glass transition temperature is determined as the temperature at the maximum point of tan δ (loss modulus / storage modulus) obtained under the measurement conditions of a sample size of 5 mm in width × 20 mm in length and a frequency of 1 MHz.

[0028] The method for producing a three-dimensional object using the resin composition for three-dimensional object of the present invention is not particularly limited and can be appropriately selected depending on the purpose. For example, a method for producing a three-dimensional object by a stereolithography method can be mentioned.

[0029] (Method of manufacturing three-dimensional objects) The method for producing a three-dimensional object of the present invention is a method for producing a three-dimensional object by a stereolithography method, comprising the steps of: The method includes a step of immersing a modeling stage in a modeling tank containing the resin composition for three-dimensional modeling of the present invention, and irradiating the resin composition for three-dimensional modeling on the modeling surface of the modeling stage with active energy rays to harden it, and further includes other steps as necessary. In the present invention, a suspension type stereolithography method is preferred in which a cured layer of the resin composition for three-dimensional modeling is laminated in the direction of gravity on the modeling surface of a modeling stage.

[0030] Specifically, the method for producing a three-dimensional object of the present invention is a method for forming a cured layer by selectively irradiating a layer of a resin composition for three-dimensional modeling with active energy rays so as to obtain a cured layer having a desired pattern based on shape data of the three-dimensional object to be produced, and then supplying a layer of an uncured resin composition for three-dimensional modeling in contact with the cured layer, and similarly irradiating the layer with active energy rays to form a new cured layer continuous with the cured layer, by repeating this lamination operation, finally obtaining the desired three-dimensional object.

[0031] Examples of the active energy rays include ultraviolet rays, electron beams, X-rays, radiation, and high frequency waves. Among them, ultraviolet rays having a wavelength of 300 nm to 400 nm are preferably used from an economical viewpoint. In this case, as the light source, ultraviolet lasers, high pressure mercury lamps, ultra-high pressure mercury lamps, low pressure mercury lamps, xenon lamps, halogen lamps, metal halide lamps, ultraviolet LEDs (light emitting diodes), ultraviolet fluorescent lamps, and the like can be used. Examples of the ultraviolet lasers include semiconductor pumped solid-state lasers, Ar lasers, and He-Cd lasers.

[0032] (3D model) The three-dimensional object of the present invention is formed by laminating cured products containing the resin composition for three-dimensional object formation of the present invention. The use of the three-dimensional object is not particularly limited and can be appropriately selected depending on the purpose, and can be used for various purposes such as sports goods, medical and nursing care products, artificial limbs, artificial teeth, artificial bones, industrial machinery and equipment, precision instruments, electric and electronic devices, electric and electronic parts, building materials, artificial baits (lures), etc. Among these, artificial baits are preferred because of the following advantages.

[0033] <True bait> The artificial bait (lure) has a structure that mimics the body of a small fish, and is modeled using the resin composition for three-dimensional modeling of the present invention, which can be modeled using a 3D printer using the stereolithography method. Since the artificial bait is modeled using the resin composition for three-dimensional modeling of the present invention, it is possible to prevent a repellent reaction in the target fish because it does not have an odor derived from a low molecular weight monofunctional monomer. In addition, since the artificial bait does not have an odor derived from a low molecular weight monofunctional monomer, when a smell that fish likes (amino acid smell) is added, the odor is not obstructed. In addition, since the resin composition for three-dimensional modeling of the present invention is biodegradable, it can be decomposed by enzymes in water. Furthermore, by mixing a biodegradable pigment into the resin composition for three-dimensional modeling of the present invention and modeling it using a UV-curable 3D printer such as an inkjet printer, it is possible to model a colorful lure in which multiple colors coexist in one three-dimensional model without painting or the like while maintaining biodegradability.

[0034] Here, as shown in FIG. 7, the artificial lure has a structure that imitates the body of a small fish. It also has several hooks 1, 7, and 8 in parts for tying to a fishing line and to a fishing hook, as necessary. It also has several fins, taking into account water resistance as necessary, and preferably has fin 3, pectoral fin 4, pelvic fin 5, and caudal fin 6. The size of the artificial lure depends on the tolerance of the 3D printer, but the size (length L, height M) can be adjusted as desired. 2 in FIG. 7 is a fish eye. EXAMPLES

[0035] Examples of the present invention will be described below, but the present invention is not limited to these examples.

[0036] Example 1 -Synthesis of multifunctional urethane (meth)acrylates with polycaprolactone backbone- In a 300 mL three-neck flask, 209 g (0.39 mol) of PLACCEL 205U (PCL205U, polycaprolactone diol, molecular weight: 530, manufactured by Daicel Corporation) was mixed with 100 g (0.71 mol) of 2-isocyanate ethyl acrylate (product name: Karenz AOI, manufactured by Showa Denko K.K.) so that the amount was 0.9 equivalents relative to the hydroxyl value of the polycaprolactone diol. The flask was sealed and stirred at 60°C for 3 days to produce a colorless liquid (polyfunctional urethane (meth)acrylate having a polycaprolactone skeleton). The liquid thus obtained was analyzed using a Fourier transform infrared spectrophotometer (FT-IR, device name: Nicolet iS2, manufactured by Thermo) at 2,250 cm -1 Disappearance of the isocyanate peak near 3,100 cm -1 ~3,600cm -1 Confirm that the hydroxyl group (OH) peak at 1,550 cm has disappeared. -1 A new peak for the nearby amide (HNC=O) bond was generated.

[0037] -Preparation of resin composition for three-dimensional modeling- Next, 4 parts by mass of a photopolymerization initiator (Omnirad TPO-H, manufactured by IGM Resins BV) was added to 100 parts by mass of the obtained polyfunctional urethane (meth)acrylate having a polycaprolactone skeleton, and mixed to prepare a resin composition for three-dimensional modeling.

[0038] Example 2 A colorless liquid (polyfunctional urethane (meth)acrylate having a polycaprolactone skeleton) was obtained in the same manner as in Example 1, except that 209 g (0.39 mol) of PLACCEL 205U (PCL205U, polycaprolactone diol, molecular weight: 530, manufactured by Daicel Corporation) was changed to 217 g (0.39 mol) of PLACCEL 305 (PCL305, polycaprolactone triol, molecular weight: 550, manufactured by Daicel Corporation).

[0039] -Preparation of resin composition for three-dimensional modeling- Next, 4 parts by mass of a photopolymerization initiator (Omnirad TPO-H, manufactured by IGM Resins BV) was added to 100 parts by mass of the obtained polyfunctional urethane (meth)acrylate having a polycaprolactone skeleton and mixed to prepare the resin composition for three-dimensional modeling of Example 1.

[0040] Example 3 A colorless liquid (polyfunctional urethane (meth)acrylate having a polycaprolactone skeleton) was obtained in the same manner as in Example 1, except that 209 g (0.39 mol) of PLACCEL 205U (PCL205U, polycaprolactone diol, molecular weight: 530, manufactured by Daicel Corporation) was changed to 335 g (0.39 mol) of PLACCEL 308 (PCL308, polycaprolactone triol, molecular weight: 850, manufactured by Daicel Corporation).

[0041] -Preparation of resin composition for three-dimensional modeling- Next, 4 parts by mass of a photopolymerization initiator (Omnirad TPO-H, manufactured by IGM Resins BV) was added to 100 parts by mass of the obtained polyfunctional urethane (meth)acrylate having a polycaprolactone skeleton and mixed to prepare the resin composition for three-dimensional modeling of Example 3.

[0042] Comparative Example 1 A colorless liquid (polyfunctional urethane (meth)acrylate having a polycaprolactone skeleton) was obtained in the same manner as in Example 1, except that 209 g (0.39 mol) of PLACCEL 205U (PCL205U, polycaprolactone diol, molecular weight: 530, manufactured by Daicel Corporation) was changed to 118 g (0.39 mol) of PLACCEL 303 (PCL303, polycaprolactone triol, molecular weight: 300, manufactured by Daicel Corporation).

[0043] -Preparation of resin composition for three-dimensional modeling- Next, 4 parts by mass of a photopolymerization initiator (Omnirad TPO-H, manufactured by IGM Resins BV) was added to 100 parts by mass of the obtained polyfunctional urethane (meth)acrylate having a polycaprolactone skeleton and mixed to prepare a resin composition for three-dimensional modeling of Comparative Example 1.

[0044] Comparative Example 2 A colorless liquid (polyfunctional urethane (meth)acrylate having a polycaprolactone skeleton) was obtained in the same manner as in Example 1, except that 209 g (0.39 mol) of PLACCEL 205U (PCL205U, polycaprolactone diol, molecular weight: 530, manufactured by Daicel Corporation) was changed to 492 g (0.39 mol) of PLACCEL 312 (PCL312, polycaprolactone triol, molecular weight: 1250, manufactured by Daicel Corporation).

[0045] -Preparation of resin composition for three-dimensional modeling- Next, 4 parts by mass of a photopolymerization initiator (Omnirad TPO-H, manufactured by IGM Resins BV) was added to 100 parts by mass of the obtained polyfunctional urethane (meth)acrylate having a polycaprolactone skeleton and mixed to prepare a resin composition for three-dimensional modeling of Comparative Example 2.

[0046] Comparative Example 3 Product name: "ELEGOO", UV resin for stereolithography 3D printers (gray), manufactured by ELEGOO, was prepared as a resin composition for three-dimensional modeling in Comparative Example 3. As a result of the inventors' analysis of the composition of "ELEGOO" of Comparative Example 3, it was found that it contained a low molecular weight acrylic monomer (acryloylmorpholine) and a high molecular weight urethane acrylate.

[0047] Comparative Example 4 Product name: "eSun", LED UV resin for stereolithography 3D printers, photocurable PLA resin for 3D printers, manufactured by eSun, was prepared as a resin composition for stereolithography in Comparative Example 4. The present inventors analyzed the composition of "eSun" of Comparative Example 4 and found that it contained a low molecular weight acrylic monomer (acryloylmorpholine) and a high molecular weight urethane acrylate.

[0048] Next, the properties of each of the obtained resin compositions for three-dimensional object formation were evaluated as follows. The results are shown in Tables 1 and 2.

[0049] <Viscosity> The viscosity of each of the obtained resin compositions for three-dimensional modeling was measured at a shear rate of 100 (1 / s) in a 25° C. environment using a rotational rheometer (device name: AR-G2, manufactured by TA Instruments).

[0050] <3D modeling> Each of the obtained resin compositions for 3D modeling was used in a 3D modeling manufacturing device (device name: ELEGOO MARS PRO UV, manufactured by ELEGOO) which is a suspension type stereolithography method, to produce 3D objects having the shapes and sizes shown in Figures 2 and 4, and the 3D modeling properties were evaluated. In Examples 1 to 3 and Comparative Example 4, a three-dimensional object could be correctly fabricated as shown in Fig. 2. In addition, in Comparative Example 3, a three-dimensional object could be correctly fabricated as shown in Fig. 4. In contrast, in Comparative Example 1, the three-dimensional object was broken as shown in Fig. 3. This is because the three-dimensional object in Comparative Example 1 was too hard and therefore brittle, and broke at the thin-walled portion, etc., and the three-dimensional object was divided into upper and lower parts as shown in Fig. 5. In addition, in Comparative Example 2, the viscosity of the resin composition for three-dimensional modeling was high, so that even when the modeling stage 11 was raised, the resin composition for three-dimensional modeling could not reach under the modeling stage 11, as shown in Figure 6, and modeling was not possible.

[0051] <5% weight loss temperature (ease of evaporation)> The odor evaluation method was to interpret the 5% weight loss temperature as "ease of volatilization" and measure the 5% weight loss temperature of the cured product as follows. The higher the 5% weight loss temperature, the less volatilization there is and the less odor is generated. Each resin composition for three-dimensional modeling was applied between two polyethylene terephthalate (PET) films, and then irradiated with UV light (0.5 J / cm) on a UV conveyor. 2 ) x 6 times to obtain cured products each having dimensions of 3 cm x 3 cm x 0.5 mm in length x width x thickness. For each of the obtained cured products, thermogravimetric analysis (TGA: ThermoGarvimetric Analysis, device name: TG-DTA 6000, manufactured by Hitachi High-Tech Science Corporation) was carried out to measure the 5% weight loss temperature.

[0052] <Method of measuring glass transition temperature Tg and elastic modulus> The loss modulus and storage modulus were measured under the following measurement conditions using a dynamic viscoelasticity measuring device (DMA: Dynamic Mechanical Analysis) (device name: RSA-3, manufactured by TA Instruments), and the temperature at the maximum point of the obtained loss tangent tan δ (loss modulus / storage modulus) was taken as the glass transition temperature. The modulus of elasticity (representing the hardness of the cured product) below the glass transition temperature was taken as the modulus of elasticity in the glass region, and the modulus of elasticity (reflecting the crosslinking density) above the glass transition temperature was taken as the modulus of elasticity in the rubber equilibrium region. The modulus of elasticity at temperatures below the glass transition temperature Tg is preferably 1 GPa to 2.5 GPa, and the modulus of elasticity at temperatures above the glass transition temperature Tg is preferably 5 MPa to 50 MPa. The sample was prepared in the same manner as for the 5% weight loss temperature, with a width of 5 mm and a length of 20 mm, and used for the measurement. -Measurement conditions- Frequency: 1Hz Heating rate: 10℃ / min. Distortion control: 0.1%

[0053] [Table 1]

[0054] [Table 2]

[0055] Details of each component in Tables 1 and 2 are as follows. *PCL205U: Plaxel 205U, polycaprolactone diol, molecular weight 530, manufactured by Daicel Corporation *PCL303: Plaxel 303, polycaprolactone triol, molecular weight 300, manufactured by Daicel Corporation *PCL305: Plaxel 305, polycaprolactone triol, molecular weight 550, manufactured by Daicel Corporation *PCL308: Plaxel 308, polycaprolactone triol, molecular weight 850, manufactured by Daicel Corporation *PCL312: Plaxel 312, polycaprolactone triol, molecular weight 1250, manufactured by Daicel Corporation * Karenz AOI: 2-isocyanate ethyl acrylate, manufactured by Showa Denko K.K. *Omnirad TPO-H, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, IGM Resins BV

[0056] From the results of Tables 1 and 2, in Examples 1 to 3, good three-dimensional modeling was possible with a single component of polyfunctional urethane (meth)acrylate with a molecular weight of 700 to 1,300 without containing a low molecular weight monofunctional monomer. In addition, the 5% weight loss temperature in thermogravimetry (TGA) was 300°C or higher, and it was difficult to volatilize, so the generation of odor could be suppressed. In addition, it is considered that the skin irritation is small because the molecular weight is large and it is difficult to penetrate into the skin. In addition, since the polyfunctional urethane (meth)acrylate has a polycaprolactone skeleton, the three-dimensional modeled object was not brittle and had elasticity. In addition, in Comparative Example 1, the ratio (300 / 720) of caprolactone skeletons contained in the molecule of the multifunctional urethane (meth)acrylate having a polycaprolactone skeleton was small, so the flexibility of the molded object was insufficient and the elastic modulus at temperatures above the glass transition temperature Tg was high, making the three-dimensional object too hard and resulting in destruction during molding. In Comparative Example 2, since the molecular weight of the polyfunctional urethane (meth)acrylate having a polycaprolactone skeleton was large, the viscosity of the resin composition for three-dimensional modeling became high, and modeling was impossible as described above. In Comparative Examples 3 and 4, the resin compositions for 3D modeling had low viscosity and the glass transition temperature Tg of the cured products was high, making them suitable for 3D modeling. However, the 5% weight loss temperature in thermogravimetry (TGA) was 200°C or lower, making them prone to volatilization. In addition, since they contained a low-molecular-weight monofunctional monomer (acryloylmorpholine), they had a strong odor and were unsuitable for use in ordinary households. [Industrial Applicability]

[0057] The resin composition for three-dimensional modeling of the present invention has low odor, excellent mechanical properties, and can stably mold objects of desired three-dimensional shapes, and can therefore be suitably used for producing three-dimensional objects such as artificial bait. [Explanation of symbols]

[0058] 11 Modeling Stage 11a Modeling surface 12 Three-dimensional sculpture 13 Linear guide 14 Arm 15 UV light source 16 Modeling tank 17 Resin composition for three-dimensional modeling (liquid)

Claims

1. Contains a polyfunctional urethane (meth)acrylate having a molecular weight of 700 or more and 1,300 or less, The content of the polyfunctional urethane (meth)acrylate in the resin composition for three-dimensional object formation is 90% by mass or more based on the total amount of the resin composition for three-dimensional object formation.

2. The resin composition for three-dimensional object formation according to claim 1 , wherein the polyfunctional urethane (meth)acrylate has a polycaprolactone skeleton.

3. 3. The resin composition for three-dimensional object formation according to claim 2, wherein the molecular weight of the polycaprolactone skeleton is 500 or more and 1,000 or less.

4. 4. The resin composition for three-dimensional object formation according to claim 2, wherein the polyfunctional urethane (meth)acrylate having a polycaprolactone skeleton is represented by the following general formula (1) or (2): 【Chemistry 1】 In the above general formula (1), R １ represents a linear alkyl group or a linear alkyl ether group, n1+n2 is an integer of 2 or more and 9 or less, and n3 is an integer of 1 or more. 【Chemistry 2】 In the above general formula (2), R ２ represents a branched alkyl group, m1+m2+m3 is an integer of 3 or more and 9 or less, and m4 is an integer of 1 or more.

5. The resin composition for three-dimensional object formation according to claim 1 , further comprising a photopolymerization initiator.

6. The resin composition for three-dimensional object formation according to claim 1 , which has a viscosity at 25° C. of 0.1 Pa·s or more and 10 Pa·s or less.

7. A method for producing a three-dimensional object by a stereolithography method, comprising the steps of:

7. A method for producing a three-dimensional object, comprising the steps of: immersing a modeling stage in a modeling tank containing the resin composition for three-dimensional modeling according to claim 1; and irradiating the resin composition for three-dimensional modeling on the modeling surface of the modeling stage with active energy rays to harden the resin composition.

8. The method for manufacturing a three-dimensional object according to claim 7 , wherein a cured layer of the resin composition for three-dimensional object manufacturing is laminated in a gravitational direction relative to a modeling surface of a modeling stage.

9. A three-dimensional object obtained by laminating a cured product containing the resin composition for three-dimensional object formation according to claim 1 .

10. The three-dimensional object according to claim 9, which is a lure.

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