Curable composition for three-dimensional stereolithography, method for producing same, method for producing three-dimensional stereolithographic product, and method for producing dental restoration article

Abstract

Provided are: a curable composition for three-dimensional stereolithography, which contains 100 parts by mass of a polymerizable monomer component (A), 40-400 parts by mass of an inorganic filler (B), 0.01-5 parts by mass of a photoinitiator (C), and 0.01-2.5 parts by mass of an activation light absorber (D), and in which 10-90 mass% of the inorganic filler (B) is contained as an organic-inorganic composite filler (E), the value of light scattering index Sc serving as an index of the proportion of light scattered laterally when being irradiated with activation light is 10% or less, and the rate of transmission for activation light in a state prior to being optically cured is 1-50%; and a method for producing the curable composition for three-dimensional stereolithography. The present invention also provides a method for producing a three-dimensional stereolithographic product and a method for producing a dental restoration article, in both of which said curable composition for three-dimensional stereolithography is used.

Description

CURABLE COMPOSITION FOR 3D PHOTO-PRODUCTION AND ITS PRODUCTION METHOD, METHOD FOR PRODUCING 3D PHOTO-PRODUCED OBJECT, AND METHOD FOR PRODUCING DENTAL RESTORATION

[0001] The present disclosure relates to a curable composition for three-dimensional stereolithography and a method for producing the same, a method for producing a three-dimensional stereolithography object, and a method for producing a dental restoration.

[0002] The technology of forming a three-dimensional object by irradiating a photocurable composition (also called a photocurable resin or a photocurable resin composition) containing a polymerizable monomer and a photopolymerization initiator with light that activates the photopolymerization initiator (activating light) to harden the composition is known as a stereolithography method. There are several stereolithography methods, and among them, the liquid vat photopolymerization method is widely used because the equipment is relatively inexpensive and it can produce objects with smooth surfaces with high precision.

[0003] In the liquid vat photopolymerization method, a three-dimensional object is typically obtained as follows. First, the height direction of the three-dimensional object is digitized and ranked from three-dimensional shape data representing the shape of the three-dimensional object, and two-dimensional shape data representing the cross-sectional shape of the three-dimensional object at each ranked height is generated. Next, activating light is applied to a liquid photocurable composition held in a vat at predetermined positions determined based on the two-dimensional shape data, selectively curing the liquid photocurable composition present at those positions to form a modeling layer having the cross-sectional shape. Furthermore, modeling layers having the cross-sectional shapes at each height are sequentially formed and stacked in the ranked order to obtain a laminate having a shape corresponding to the shape of the three-dimensional object. The laminate is then washed with an organic solvent, if necessary, and then subjected to secondary curing to obtain the desired object.

[0004] In the field of dentistry, dental restorations such as dentures and crown prostheses must be manufactured with high precision in a unique shape that is tailored to the condition of the oral cavity of each individual patient. For this reason, the manufacture of dental restorations by stereolithography using a liquid vat photopolymerization method has been considered, based on CAD (Computer Aided Design) data designed using digital data obtained by intraoral scanning or the like.

[0005] Dental prostheses used in the oral cavity require not only high dimensional (shape) accuracy as described above, but also high mechanical strength sufficient to withstand the loads imposed by mastication. In this regard, when an inorganic filler is incorporated into a photocurable composition, polymerization shrinkage, which is one of the causes of reduced accuracy, can be reduced, and the mechanical strength and surface hardness of the cured product can be improved. For this reason, liquid vat photopolymerization using a photocurable composition containing an inorganic filler is considered suitable for stereolithography of dental prostheses, and curable compositions for three-dimensional stereolithography containing such inorganic fillers have also been proposed.

[0006] For example, Patent Document 1 discloses a composition for optical 3D modeling that exhibits excellent molding accuracy, mechanical properties, and transparency, and is particularly suitable for dental materials. The composition contains a polymerizable monomer (a), ultraviolet-absorbing inorganic particles (b), and a photopolymerization initiator (c). Patent Document 2 discloses a resin composition capable of producing a cured product (3D object) with excellent designability, the composition containing a light-transmitting resin and two or more types of light-transmitting particles with different refractive indices and Abbe numbers. Patent Document 3 discloses a resin composition for optical 3D modeling that can produce a 3D object with high strength, high elasticity, and excellent abrasion resistance. The composition contains a urethane-modified (meth)acrylic compound (a), a (meth)acrylamide compound (b), a photopolymerization initiator (c), and spherical inorganic particles (d) having an average particle size of 0.75 to 10 μm, the content of the spherical inorganic particles (d) being 50 to 400 parts by mass per 100 parts by mass of the total amount of the polymerizable monomers. Furthermore, Patent Document 4 discloses that an organic-inorganic composite filler containing inorganic agglomerated particles formed by agglomerating inorganic primary particles having an average particle size of 10 to 1,000 nm, an organic resin phase containing a polymerized and cured product of a polymerizable monomer that covers the surface of each inorganic primary particle and bonds each inorganic primary particle to one another, and a water-absorbent resin is added to a dental curable composition, for the purposes of reducing the viscosity of the paste, improving workability, suppressing polymerization shrinkage during curing, and improving the mechanical strength of the cured product while maintaining the surface smoothness of the cured product.

[0007] International Publication No. 2018 / 074380 Japanese Patent Application Laid-Open No. 2020-180171 Japanese Patent Application Laid-Open No. 2022-41276 International Publication No. 2013 / 039169 Japanese Patent No. 3917204

[0008] Patent Documents 1 to 3 use compositions containing polymerizable monomers and inorganic fillers, which allows for the production of molded objects with excellent mechanical strength, elastic modulus, and abrasion resistance. However, the optical 3D modeling composition described in Patent Document 1 has low fluidity, which may limit the shape of the object that can be manufactured. Furthermore, the resin composition described in Patent Document 2 may experience sedimentation of the translucent particles (e.g., glass filler) contained in the composition when left stationary for a long period of time. Furthermore, it has been revealed that the stereolithography resin composition described in Patent Document 3 often causes fine cracks on the surface of the molded object that are difficult to detect visually (see FIG. 4). When a molded object having such fine cracks is used as a dental prosthesis, it may become a starting point for fracture of the dental prosthesis in the oral cavity, which is problematic.

[0009] Therefore, an object of the present disclosure is to provide a technology that enables the production of high-precision, high-strength three-dimensional objects without generating cracks on the surface when producing three-dimensional objects by photolithography using a liquid vat photopolymerization method using a curable composition for three-dimensional photolithography that contains a certain amount of inorganic filler to increase strength.

[0010] A first aspect of the present disclosure relates to a liquid tank photopolymerization method for producing a three-dimensional optically modeled object by irradiating a predetermined position of a liquid photocurable composition held in a tank with activating light (hereinafter also referred to as "specific activating light") containing light of a specific wavelength λ (nm) in the ultraviolet or visible light region to selectively cure the liquid photocurable composition present at that position, the method comprising: a curable composition for three-dimensional optical modeling used as the liquid photocurable composition, the curable composition comprising: 100 parts by mass of a polymerizable monomer component (A); 40 to 400 parts by mass of an inorganic filler (B) composed of one or more types of inorganic powder or particles; 0.01 to 5 parts by mass of a photopolymerization initiator (C) having the function of initiating photopolymerization upon irradiation with the specific activating light; and 0.01 to 2.5 parts by mass of an activating light absorber (D) having the function of absorbing the specific activating light but not having photopolymerization initiation ability; In the particle size distribution of the inorganic filler (B) measured by a microscopy method using a scanning microscope, 80% or more of all primary particles constituting the inorganic filler (B) are particles having a particle diameter of 0.05 to 5.0 μm; 10 to 90 mass% of the inorganic filler (B) is contained as an organic-inorganic composite filler (E) consisting of particles constituted by a composite material of the inorganic filler (B) and a resin (R); when, among the inorganic fillers (B), those not composited with the resin (R) are defined as non-composite inorganic fillers (B1) and those contained as the organic-inorganic composite filler (E) are defined as composite inorganic fillers (B2), 80% or more of all primary particles constituting each of the non-composite inorganic fillers (B1) and the composite inorganic fillers (B2) are particles having a particle diameter of 0.05 to 5.0 μm; and the polymerizable monomer component (A), the non-composite inorganic filler (B1), and the organic-inorganic composite filler (E) are When a composition consisting of only the polymerizable monomer component (A), the non-composite inorganic filler (B1), and the organic-inorganic composite filler (E), in which the compositional ratio of these components is the same as that of the curable composition for three-dimensional stereolithography of the present disclosure, is used as a base composition, a measurement light beam containing the specific wavelength λ (nm), containing light within a range of λ±50 (nm) as a main component and exhibiting the maximum intensity within the range is measured using a goniophotometer, and based on the intensity of transmitted light in a specific output angle direction, the following formula can be calculated: Sc={(I７０ +I ７５ +I ８０ ) / (I ０ ×3)}×100 (where, I ０ , I ７０ , I ７５ , and I ８０ indicates the intensity of transmitted light in each direction at an emission angle of 0°, 70°, 75°, and 80°, respectively.) The light scattering index: Sc (%) determined by the above formula is 10(%) or less, and the transmittance of a specific activating light measured on a 0.5 mm thick sample made of the curable composition for three-dimensional stereolithography is 1 to 50(%).

[0011] A second aspect of the present disclosure is a method for producing a curable composition for three-dimensional optical shaping according to the present disclosure, comprising a mixing step of mixing a polymerizable monomer component (A), a non-composite inorganic filler (B1), an organic-inorganic composite filler (E), a photopolymerization initiator (C), and an activating light absorber (D), wherein the refractive index of the polymerizable monomer component (A) with respect to the D line at 25°C and the refractive index with respect to the specific activating light at 25°C are respectively n （Ｄ）Ｍ and n （ＡＬ）Ｍ The refractive index of the inorganic powder particles constituting the inorganic filler (B) with respect to the D line at 25° C. and the refractive index with respect to the specific activating light at 25° C. are respectively n （Ｄ）Ｆ and n （ＡＬ）Ｆ The refractive index of the resin (R) contained in the organic-inorganic composite filler (E) at 25°C with respect to the specific activating light is n （ＡＬ）Ｒand a composition consisting only of a polymerizable monomer component (A), a non-composite inorganic filler (B1), and an organic-inorganic composite filler (E), in which the compositional ratio of these components is the same as that of the curable composition for three-dimensional stereolithography that is the target of production, is used as a base composition, in the mixing step, the polymerizable monomer component (A), the non-composite inorganic filler (B1), and the organic-inorganic composite filler (E) must satisfy the following conditions 1 to 6: Condition 1: When the particle diameter of each primary particle constituting the inorganic filler (B) is x (nm) and pi is π, in the particle size distribution of the inorganic filler (B) measured by a microscopy method using a scanning microscope, the total number of particles having a particle diameter x (nm) in the range of 0.7λ / π to 4λ / π (nm) is 40% or more of the total number of primary particles constituting the inorganic filler (B); Condition 2: When the refractive index n （Ｄ）Ｆ When inorganic powder particles (b1) are inorganic powder particles consisting of an aggregate of a single type of inorganic particles having a refractive index in the range of 1.500 to 1.550, and inorganic powder particles (b2) are inorganic powder particles consisting of an aggregate of a single type of inorganic particles having a refractive index outside the above range, the non-composite inorganic filler (B1) and the composite inorganic filler (B2) are each: (1) composed of a single type of specific inorganic powder particle (b1), or (2) composed of a plurality of types of specific inorganic powder particle (b1), and at least one of the plurality of types of specific inorganic powder particle (b1) accounts for 10 mass% or more of the total mass of each of the non-composite inorganic filler (B1) and the composite inorganic filler (B2), or (3) A single or multiple specific inorganic powder or particles (b1): 90% by mass or more and less than 100% by mass, and a single or multiple non-specific inorganic powder or particles (b2): more than 0% by mass and 10% by mass or less, and at least one of the single or multiple specific inorganic powder or particles (b1) accounts for 10% by mass or more of the total mass of the non-composite inorganic filler (B1) and the composite inorganic filler (B2); Condition 3: Refractive index n （Ｄ）Ｍ is in the range of 1.490 to 1.550; Condition 4: The refractive index n of at least one specific inorganic powder or particle (b1) that accounts for 10% by mass or more of the total mass of each of the non-composite inorganic filler (B1) and the composite inorganic filler (B2) is （Ｄ）Ｆ Among them, the refractive index n （Ｄ）Ｍ The refractive index where the difference between（Ｄ）Ｆｈ When （Ｄ）Ｆｈ and （Ｄ）Ｍ Absolute value of the difference with: |n （Ｄ）Ｆｈ -n （Ｄ）Ｍ Condition 5: the refractive index n of at least one specific inorganic powder or particle (b1) that accounts for 10% by mass or more of the total mass of each of the non-composite inorganic filler (B1) and the composite inorganic filler (B2) is 0.035 or less; （ＡＬ）Ｆ and the refractive index n （ＡＬ）Ｍ and the refractive index n （ＡＬ）Ｒ and the following formulas (i) to (iii): −0.015<(n （ＡＬ）Ｆ -n （ＡＬ）Ｍ )<0.025 (i) -0.015<(n （ＡＬ）Ｒ -n （ＡＬ）Ｍ )<0.030 (ii) -0.020<(n （ＡＬ）Ｆ -n （ＡＬ）Ｒ ) < 0.020 (iii) is satisfied; Condition 6: A sample of the base composition having a thickness of 0.5 mm is irradiated perpendicularly with measurement light containing light of a specific wavelength: λ (nm), containing light mainly within a range of λ ± 50 (nm) and exhibiting the maximum intensity within said range, using a goniophotometer, and the following formula is satisfied based on the intensity of transmitted light in a specific emission angle direction: Sc = {(I ７０ +I ７５ +I ８０ ) / (I ０ ×3)}×100 (where, I ０ , I ７０ , I ７５ , and I ８０ indicates the intensity of transmitted light in each direction at an emission angle of 0°, 70°, 75°, and 80°, respectively.) The light-scattering index: Sc (%) determined by

[0012] A third aspect of the present disclosure is a method for manufacturing a three-dimensional optically shaped object by irradiating a predetermined position of a liquid photocurable composition held in a tank with specific activating light to selectively cure the liquid photocurable composition present at that position, thereby manufacturing a three-dimensional optically shaped object, the method comprising: a molding step of: digitizing and ranking the height direction of the three-dimensional object from three-dimensional shape data representing the shape of the three-dimensional object and generating two-dimensional shape data representing the cross-sectional shape of the three-dimensional object at each ranked height; irradiating the liquid photocurable composition held in the tank with specific activating light at a predetermined position determined based on the two-dimensional shape data, thereby selectively and primarily curing the liquid photocurable composition present at that position to form a modeling layer having the cross-sectional shape; and sequentially forming and stacking modeling layers having the cross-sectional shapes at each height in the order of the ranking, thereby obtaining a laminate having a shape corresponding to the shape of the three-dimensional object; a cleaning step of washing the laminate obtained in the molding step with an organic solvent; and a secondary curing step of performing additional irradiation of activating light, heat treatment, or both on the laminate washed in the cleaning step to secondary cure the laminate; The method for producing a three-dimensional optically shaped object uses the curable composition for three-dimensional optical shaping of the present disclosure as the liquid photocurable composition.

[0013] A fourth aspect of the present disclosure is a method for manufacturing a dental restoration, including manufacturing a dental restoration by the method for manufacturing a three-dimensional optically shaped object of the present disclosure.

[0014] The curable composition for three-dimensional stereolithography of the present disclosure contains a certain amount of inorganic filler to increase strength, while still maintaining fluidity that allows it to be molded using a three-dimensional stereolithography device. According to the method for producing a three-dimensional stereolithography object of the present disclosure using the curable composition for three-dimensional stereolithography, it is possible to produce a three-dimensional stereolithography object that has excellent mechanical strength and good shape accuracy while preventing cracks from occurring on the surface.

[0015] FIG. 1 is a diagram showing an optical microscope image (magnification 50x) of the surface (evaluation A0) of a three-dimensional stereolithography object obtained in Reference Example 7. FIG. 2 is a diagram showing an optical microscope image (magnification 50x) of the surface (evaluation B) of a three-dimensional stereolithography object obtained in Reference Example 11. FIG. 3 is a diagram showing an optical microscope image (magnification 50x) of the surface (evaluation D) of a three-dimensional stereolithography object obtained in Reference Comparative Example 1. FIG. 4 is a diagram showing an optical microscope image (magnification 50x) of the surface (evaluation C) of a three-dimensional stereolithography object obtained in Reference Comparative Example 9. FIG. 5 is a graph showing the wavelength distribution of measurement light used when measuring the light scattering index Sc in the examples and reference examples. FIG. 6 is a diagram showing an optical microscope image (magnification 50x) of the surface (evaluation A1) of a three-dimensional stereolithography object obtained in Example 1.

[0016] 1. Overview of the Curable Composition for Three-Dimensional Stereolithography of the Present Disclosure The curable composition for three-dimensional stereolithography of the present disclosure (hereinafter also simply referred to as the "curable composition for stereolithography") is a composition used as a liquid photocurable composition when producing a three-dimensional object using a liquid vat photopolymerization method, i.e., a curable composition for three-dimensional stereolithography by a liquid vat photopolymerization method.

[0017] Here, the liquid vat photopolymerization method refers to a process that includes the steps of: digitizing and ranking the height direction of a three-dimensional object from three-dimensional shape data representing the shape of the three-dimensional object; generating two-dimensional shape data representing the cross-sectional shape of the three-dimensional object at each ranked height; irradiating a liquid photocurable composition held in a vat with activating light at a predetermined position determined in advance based on the two-dimensional shape data, thereby selectively (primarily) curing the liquid photocurable composition present at that position to form a modeling layer having the cross-sectional shape; and sequentially forming and stacking modeling layers having the cross-sectional shapes at each height in accordance with the ranking order to obtain a laminate having a shape corresponding to the shape of the three-dimensional object (hereinafter also referred to as the "molding process"). If necessary, a cleaning process using an organic solvent (hereinafter also referred to as the "cleaning process") or a secondary curing process (hereinafter also referred to as the "secondary curing process") is performed to obtain a three-dimensional photo-printed object having a shape corresponding to the shape of the three-dimensional object.

[0018] As described above, photocurable compositions containing a certain amount of inorganic filler to improve the mechanical strength and surface hardness of the cured product can suffer from problems such as reduced fluidity and particle settling during storage. Furthermore, when a model is produced by a liquid tank photopolymerization method using the stereolithography resin composition described in Patent Document 3, fine cracks that are difficult to detect visually often occur on the surface of the model (although this is not recognized in Patent Document 3).

[0019] Although the reason for the occurrence of cracks is unclear, the inventors have confirmed that cracks occur when, after obtaining a laminate using a stereolithography device, the uncured curable composition adhering to the surface of the laminate is washed with an organic solvent. Furthermore, since the inorganic filler contained in the curable composition for stereolithography contains many particles with particle sizes that cause scattering (specifically, Mie scattering or Reyleigh scattering) when irradiated with activating light, weak activating light (sideward scattered light) is generated that is scattered off the optical axis of the irradiation spot, resulting in an extremely shallow cure depth and the formation of regions with relatively low crosslink density between the layers of the laminate (hereinafter also referred to as "interlayer low crosslink density regions"). This is thought to be one of the causes of crack occurrence. Specifically, when an organic solvent penetrates into the interlayer low crosslink density regions during washing, the regions swell, widening the molecular distances between the polymer chains constituting the molded body and temporarily reducing its strength. It is thought that, in this case, the internal stress remaining in the molded body during the molding process destroys the weakened portions, causing cracks to occur in the regions.

[0020] It is unclear why cracks on the surface of the cured product are not recognized in Patent Document 3, but when the present inventors conducted a follow-up experiment on the stereolithography resin composition described in Patent Document 3, the stereolithography resin composition in which cracks were observed on the surface of the cured product had low transmittance of activating light. From this, it is believed that the occurrence of cracks was probably overlooked in Patent Document 3.

[0021] The present inventors have found that these problems can be solved by controlling the particle size of the inorganic filler particles and by setting the transmittance of the composition before curing to a specific range of specific activating light, and have proposed a novel curable composition for three-dimensional stereolithography (Japanese Patent Application No. 2023-018503). As a preferred embodiment, the present inventors have proposed a curable composition for three-dimensional stereolithography (hereinafter also referred to as the "proposed curable composition") having the following characteristics 1 to 4.

[0022] Feature 1: The composition contains 100 parts by mass of a polymerizable monomer component (A), 40 to 400 parts by mass of an inorganic filler (B) composed of a single type or multiple types of inorganic powder or particles, 0.01 to 5 parts by mass of a photopolymerization initiator (C) that has the function of initiating photopolymerization upon irradiation with specific activating light, and 0.01 to 2.5 parts by mass of an activating light absorber (D) that has the function of absorbing the specific activating light but does not have the ability to initiate photopolymerization.

[0023] Feature 2: In the particle size distribution of the inorganic filler (B) measured by a microscopy method using a scanning microscope, 80% or more of all primary particles constituting the inorganic filler (B) are particles having a particle diameter of 0.05 to 5.0 μm.

[0024] Feature 3: The transmittance of a 0.5 mm thick sample made of the curable composition for three-dimensional stereolithography to specific activating light is 1 to 50%.

[0025] Feature 4: When a composition consisting solely of the polymerizable monomer component (A) and the inorganic filler (B) and having the same compositional ratio as that of the curable composition for three-dimensional optical fabrication is used as a base composition, the polymerizable monomer component (A) and the inorganic filler (B) can be calculated based on the intensity of transmitted light in a specific emission angle direction obtained by measurement using a goniophotometer that irradiates a 0.5 mm thick sample made of the base composition with measurement light that contains light of a specific wavelength: λ (nm), is mainly composed of light within a range of λ±50 (nm), and exhibits the maximum intensity within the range, using the following formula: Sc={(I ７０ +I ７５ +I ８０ ) / (I ０ ×3)}×100 (where, I ０ , I ７０, I ７５ , and I ８０ indicates the intensity of transmitted light in each direction where the emission angle is 0°, 70°, 75°, and 80°, respectively.) The light scattering index: Sc (%) determined by

[0026] In the previously proposed curable composition, by containing a polymerizable monomer component and an inorganic filler in a quantity ratio that satisfies the condition shown in Feature 1, it is possible to increase the strength and surface hardness of the cured body that becomes the three-dimensional optically shaped object that is the target of manufacture. Furthermore, by having the particles that make up the inorganic filler satisfy the condition shown in Feature 2 in terms of particle diameter, it is possible to suppress an increase in viscosity of the composition and the risk of particle settling during storage. Furthermore, by satisfying the conditions shown in Feature 3 and 4, it is possible to obtain the effects of high strength, prevention of cracking, and high precision.

[0027] In order to further improve the fluidity of the previously proposed curable composition and thereby improve its operability during use (when performing three-dimensional stereolithography by liquid tank photopolymerization), the present inventors have investigated the application of the technology disclosed in Patent Document 4 to blend a part of the inorganic filler (B) as an organic-inorganic composite filler composed of particles made of a composite in which inorganic powder particles are dispersed in a resin matrix. As a result, it has been found that although the fluidity can be improved, the crack prevention effect, which is a characteristic of the previously proposed curable composition, may be impaired.

[0028] Therefore, further investigations were conducted to solve these newly identified problems, and it was found that these problems can be solved by controlling the refractive index of the polymerizable monomer component, inorganic filler, and inorganic powder and resin that make up the organic-inorganic composite filler with respect to specific activating light, which led to the completion of the present invention.

[0029] That is, the curable composition for stereolithography according to the present disclosure has the following characteristics [1] to [5] due to the inclusion of an organic-inorganic composite filler as an essential component. By having these characteristics, the curable composition for stereolithography according to the present disclosure has further improved fluidity while maintaining the characteristics of previously proposed curable compositions, namely, "there is little risk of a decrease in fluidity or sedimentation of the inorganic filler, and furthermore, the occurrence of cracks on the surface is prevented, while three-dimensional stereolithography objects having excellent mechanical strength and good shape accuracy can be produced."

[0030] Feature [1] (same as the above-mentioned feature 1): Contains 100 parts by mass of a polymerizable monomer component (A), 40 to 400 parts by mass of an inorganic filler (B) composed of a single type or multiple types of inorganic powder or particles, 0.01 to 5 parts by mass of a photopolymerization initiator (C) having a function of initiating photopolymerization upon irradiation with specific activating light, and 0.01 to 2.5 parts by mass of an activating light absorber (D) having a function of absorbing the specific activating light but not having photopolymerization initiation ability.

[0031] Feature [2] (same as the above-mentioned feature 2): In the particle size distribution of the inorganic filler (B) measured by a microscopy method using a scanning microscope, 80% or more of all primary particles constituting the inorganic filler (B) are particles having a particle diameter of 0.05 to 5.0 μm.

[0032] Feature [3]: 10 to 90 mass% of the inorganic filler (B) is blended as an organic-inorganic composite filler (E) composed of particles formed from a composite material of the inorganic filler (B) and a resin (R). When the inorganic filler (B) that is not composited with the resin (R) is defined as a non-composite inorganic filler (B1) and the inorganic filler included as the organic-inorganic composite filler (E) is defined as a composite inorganic filler (B2), both the non-composite inorganic filler (B1) and the composite inorganic filler (B2) satisfy the condition of Feature [2]. The compositions and particle size distributions of the non-composite inorganic filler (B1) and the composite inorganic filler (B2) may be the same or different. However, since inorganic powder particles prepared as the inorganic filler (B) (or prepared by mixing multiple types of inorganic powder particles) are typically used separately, it is preferable that the composition, particle size distribution, and average primary particle diameter of the two are the same or substantially the same.

[0033] Feature [4] (corresponding to the above-mentioned feature 4): When a composition consisting of only the polymerizable monomer component (A), the non-composite inorganic filler (B1), and the organic-inorganic composite filler (E) is used as a base composition, in which the composition ratio of these components is the same as that of the curable composition for three-dimensional optical modeling, a measurement light beam containing light of a specific wavelength: λ (nm), containing light mainly within a range of λ±50 (nm) and exhibiting the maximum intensity within the range is measured using a goniophotometer, and the measurement light beam is measured based on the intensity of transmitted light in a specific emission angle direction, as determined by the following formula: Sc={(I ７０ +I ７５ +I ８０ ) / (I ０ ×3)}×100 (where, I ０ , I ７０ , I ７５ , and I ８０ indicates the intensity of transmitted light in each direction where the emission angle is 0°, 70°, 75°, and 80°, respectively.) The light scattering index: Sc (%) determined by

[0034] Feature [5] (same as feature 3 above): The transmittance of a 0.5 mm thick sample made of the curable composition for three-dimensional optical fabrication to specific activating light is 1 to 50%.

[0035] Below, characteristic features [1] to [5] of the curable composition for stereolithography of the present disclosure will be described along with each component of the curable composition for stereolithography of the present disclosure. In this specification, unless otherwise specified, the expression "x to y" using the numerical values ​​x and y means "x or more and y or less." In such a notation, when a unit is assigned only to the numerical value y, the unit also applies to the numerical value x. Furthermore, in this specification, the term "(meth)acrylate" means both "acrylate" and "methacrylate." The same applies to terms such as "(meth)acryloyl."

[0036] 2. Regarding Feature [1] The curable composition for stereolithography disclosed herein contains 100 parts by mass of a polymerizable monomer component (A), 40 to 400 parts by mass of an inorganic filler (B) composed of a single type or multiple types of inorganic powder or particles, 0.01 to 5 parts by mass of a photopolymerization initiator (C) that has the function of initiating photopolymerization upon irradiation with specific activating light, and 0.01 to 2.5 parts by mass of an activating light absorber (D) that has the function of absorbing the specific activating light but does not have the ability to initiate photopolymerization.

[0037] 3. Regarding the polymerizable monomer component (A) It is preferable to use a (meth)acrylate monomer as the polymerizable monomer component (A) because it has a fast curing rate and the strength of the resulting shaped object is excellent. In order to produce a shaped object with even higher strength, it is preferable that 50% by mass or more, preferably 80% by mass or more, and more preferably 95% by mass or more of the polymerizable monomers be a bifunctional or higher polyfunctional (meth)acrylate, based on the total mass of all radically polymerizable monomers.

[0038] Suitable bifunctional or higher polyfunctional (meth)acrylates include (meth)acrylates containing a bisphenol A skeleton, such as 2,2'-bis{4-[3-(meth)acryloyloxy-2-hydroxypropoxy]phenyl}propane, 2,2'-bis[4-(meth)acryloyloxyphenyl]propane, and 2,2'-bis[4-(meth)acryloyloxypolyethoxyphenyl]propane; and ethylene glycol (meth)acrylates, such as triethylene glycol dimethacrylate and ethylene glycol dimethacrylate. acrylates; aliphatic di(meth)acrylates such as 1,3-propanediol di(meth)acrylate and 1,9-nonanediol dimethacrylate; urethane group-containing (meth)acrylates such as 1,6-bis(methacryloyloxy-2-ethoxycarbonylamino)-2,2,4-trimethylhexane; trifunctional (meth)acrylates such as trimethylolpropane trimethacrylate; and isocyanate skeleton-containing (meth)acrylates such as tris(2-methacryloyloxyethyl)isocyanurate. Among these, 2,2'-bis[4-(meth)acryloyloxyphenyl]propane, 2,2'-bis[4-(meth)acryloyloxypolyethoxyphenyl]propane, triethylene glycol dimethacrylate, tris(2-methacryloyloxyethyl)isocyanurate, etc. are preferred from the viewpoints of low viscosity and high strength.

[0039] Furthermore, examples of monofunctional (meth)acrylates suitable for use in combination with difunctional or higher polyfunctional (meth)acrylates include hydroxyethyl methacrylate, methyl (meth)acrylate, ethyl (meth)acrylate, isopropyl (meth)acrylate, hydroxyethyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, and glycidyl (meth)acrylate.

[0040] As the polymerizable monomer component (A), these (meth)acrylates may be used alone or in combination.

[0041] 4. Regarding the Inorganic Filler (B): To increase the mechanical strength, such as rigidity, of the resulting shaped object, the curable composition for stereolithography according to the present disclosure contains 40 to 400 parts by mass of the inorganic filler (B) per 100 parts by mass of the polymerizable monomer component (A). If the content of the inorganic filler (B) is too high, the viscosity of the composition will be too high. On the other hand, if the content of the inorganic filler (B) is too low, the mechanical strength will be insufficient. For this reason, the content of the inorganic filler (B) is preferably 50 to 350 parts by mass, more preferably 60 to 300 parts by mass, per 100 parts by mass of the polymerizable monomer component (A).

[0042] As shown in characteristic point [2], the inorganic filler (B) needs to have a particle size distribution measured by a microscopy method using a scanning microscope such that 80% or more (preferably 90% or more, more preferably 95% or more) of all primary particles constituting the inorganic filler (B) have a particle diameter of 0.05 to 5.0 μm.

[0043] Here, the fact that 80% or more of all primary particles constituting the inorganic filler (B) are particles with a particle diameter of 0.05 to 5.0 μm can be confirmed by the particle size distribution of the inorganic filler (B) measured by a microscopy method using a scanning microscope. That is, the inorganic filler (B) is photographed by a scanning electron microscope, and the number of all primary particles (50 or more) observed within a unit field of view of the photograph: n (numbers) is measured, and the primary particle diameter (maximum diameter): X of each particle is also measured. ｉ By measuring the particle size distribution (nm) of all particles, the particle size distribution can be determined. ｉ In the formula, i is a natural number from 1 to n, and represents the number of each measured primary particle.

[0044] Based on the measured values ​​thus obtained, the average primary particle diameter: X (nm) is calculated as the sum of the particle diameters of all the measured primary particles (primary particles where i = 1 to n): ΣX ｉ Using the formula: X = ΣX ｉ / n and can be calculated and confirmed.

[0045] The average primary particle size of the inorganic filler (B) is preferably 0.07 to 3 μm, and more preferably 0.08 to 1 μm.

[0046] By including inorganic filler (B) having such a particle size distribution in the above-mentioned ratio, it is possible to increase the strength and surface hardness of the cured body that will become the three-dimensional optically shaped object, which is the target of production. Furthermore, by having the particles constituting inorganic filler (B) satisfy the above-mentioned particle diameter conditions, it is possible to suppress an increase in viscosity of the composition and the risk of particle sedimentation during storage. From the viewpoint of further suppressing viscosity increases, the lower limit of the particle diameter of particles that account for 80% or more of inorganic filler (B) is preferably 0.08 μm, more preferably 0.1 μm. From the viewpoint of further suppressing sedimentation, the upper limit of the particle diameter of particles that account for 80% or more of inorganic filler (B) is preferably 2.0 μm, more preferably 1.0 μm.

[0047] The inorganic filler (B) may be contained as aggregated particles formed by aggregation of primary particles. The particle size distribution of the aggregated particles is not particularly limited as long as the particle size distribution of the primary particles satisfies the above-described conditions. However, in order to suppress sedimentation of the inorganic filler (B), it is preferable that the number of aggregated particles of the inorganic filler (B) contained in the curable composition for stereolithography of the present disclosure be small. The average particle size of the inorganic filler (B) including aggregated particles of primary particles measured by a laser diffraction / scattering method is typically 0.05 to 100 μm, preferably 0.05 to 50 μm, and more preferably 0.05 to 30 μm.

[0048] As shown in the characteristic point [3], the inorganic filler (B) is divided into a non-composite inorganic filler (B1) that is blended as it is without being composited with the resin (R), and a composite inorganic filler (B2) that is blended as an organic-inorganic composite filler (E). Therefore, the blending amount of the inorganic filler (B) means the combined amount of the non-composite inorganic filler (B1) and the composite inorganic filler (B2) relative to 100 parts by mass of the polymerizable monomer component (A).

[0049] As shown in characteristic point [3], 10 to 90 mass% of the inorganic filler (B) is the composite inorganic filler (B2), and the remainder is the non-composite inorganic filler (B1). If the proportion of the composite inorganic filler (B2) in the inorganic filler (B) is too high, the fluidity will be significantly reduced. On the other hand, if the proportion of the composite inorganic filler (B2) in the inorganic filler (B) is too low, it is difficult to achieve the fluidity-improving effect achieved by adding the organic-inorganic composite filler (E). For this reason, the proportion of the composite inorganic filler (B2) in the inorganic filler (B) is preferably 20 to 80 mass%, more preferably 30 to 70 mass%.

[0050] In the non-composite inorganic filler (B1) and the composite inorganic filler (B2), 80% or more (preferably 90% or more, more preferably 95% or more) of all the primary particles constituting them are particles with a particle diameter of 0.05 to 5.0 μm. The composition and particle size distribution of the non-composite inorganic filler (B1) and the composite inorganic filler (B2) may be the same or different, but since inorganic powder particles prepared as the inorganic filler (B) (or prepared by mixing multiple types of inorganic powder particles, etc.) are usually used separately, it is preferable that the composition, particle size distribution, and average primary particle diameter of both are the same or substantially the same. Note that "substantially the same" basically means that the difference is within the range of measurement error.

[0051] As the inorganic filler (B), inorganic powders and granules used as inorganic fillers in dental restorative materials can be used without particular limitation, provided that the conditions set forth in Feature [5] and the conditions set forth in Feature [4] are satisfied. From the viewpoint of ease of satisfying these prerequisites, it is preferable to use inorganic powders and granules composed of particles of amorphous silica; silica-based composite oxides such as silica-zirconia, silica-titania, silica-titania-barium oxide, and silica-titania-zirconia; and glasses such as borosilicate glass, aluminosilicate glass, and fluoroaluminosilicate glass. Furthermore, from the viewpoint of X-ray contrast properties, it is more preferable to use particles composed of silica-based composite oxides such as silica-zirconia, silica-titania, silica-titania-barium oxide, and silica-titania-zirconia. Furthermore, from the viewpoint of the abrasion resistance of the cured body, it is even more preferable to use inorganic powders and granules composed of silica-zirconia particles.

[0052] It is desirable to treat the inorganic powder or granule with any surface treatment agent, such as a silane coupling agent, in order to improve compatibility with the polymerizable monomer component (A) and to improve mechanical strength and water resistance. The surface treatment may be carried out by a known method. Examples of silane coupling agents include methyl trimoxysilane, methyl triethoxysilane, methyl trichlorosilane, dimethyl dichlorosilane, trimethyl chlorosilane, vinyl trichlorosilane, vinyl triethoxysilane, vinyl tris(β-methoxyethoxy)silane, γ-methacryloyloxypropyl trimethoxysilane, methacryloyloxyoctyl-8-trimethoxysilane, γ-chloropropyl trimethoxysilane, γ-glycidoxypropyl methoxysilane, and hexamethyldisilazane.

[0053] 5. Regarding the Photopolymerization Initiator (C): The photopolymerization initiator (C) must have the ability to generate radicals and radically polymerize the polymerizable monomer component when exposed to specific activating light, including light of a specific wavelength λ (nm) in the ultraviolet or visible light region, irradiated from a light source installed in the stereolithography device. In other words, the photopolymerization initiator (C) must absorb light of a specific wavelength λ (nm) to generate radicals. The specific wavelength λ, as long as it is in the ultraviolet or visible light region, may be appropriately determined depending on the wavelength of the activating light used in the stereolithography device. Examples of general-purpose stereolithography devices include SLA-type stereolithography devices that irradiate semiconductor laser light as the activating light, DLP-type stereolithography devices that irradiate projector light, and LCD-type stereolithography devices that irradiate liquid crystal panel light, and the like. Light sources with activating light wavelengths of 405 nm or 385 nm are often used. In the present disclosure, the specific wavelength λ is preferably 405 nm or 385 nm, and the optical shaping apparatus is preferably an SLA type, a DLP type, or an LCD type.

[0054] The amount of photopolymerization initiator (C) to be blended may be 0.05 to 5.0 parts by mass per 100 parts by mass of polymerizable monomer component (A). If the amount of photopolymerization initiator (C) to be blended is too high, burrs and the like will occur in the resulting shaped object, resulting in poor precision. On the other hand, if the amount of photopolymerization initiator (C) to be blended is too low, shaping will not be possible in the molding process. For this reason, the amount of photopolymerization initiator (C) to be blended is preferably 0.3 to 4.0 parts by mass, more preferably 0.5 to 3.0 parts by mass, per 100 parts by mass of polymerizable monomer component (A).

[0055] The photopolymerization initiator (C) may be appropriately selected from known photopolymerization initiators that satisfy the above conditions. The photopolymerization initiator to be selected is not particularly limited, and examples thereof include self-cleavage photopolymerization initiators, bimolecular hydrogen abstraction photopolymerization initiators, photoacid generators, and combinations thereof. These photopolymerization initiators may be used in combination with a photosensitizing dye, an electron-donating compound, or the like.

[0056] Suitable self-cleavage photopolymerization initiators include acylphosphine oxide compounds such as diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide and phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide; benzoketal compounds, benzyne compounds, α-aminoacetophenone compounds, α-hydroxyacetophenone compounds, titanocene compounds, and acyloxime compounds. Examples of photoacid generators include iodonium salt compounds such as p-isopropylphenyl-p-methylphenyliodonium tetrakispentafluorophenylborate salt; sulfonium salt compounds such as dimethylphenacylsulfonium hexafluoroantimonate salt; and halomethyl-substituted triazine compounds such as 2,4,6-tris(trichloromethyl)-s-triazine. Examples of photosensitizing dyes include ketone compounds, coumarin dyes, cyanine dyes, merocyanine dyes, thiazine dyes, azine dyes, acridine dyes, xanthene dyes, squarium dyes, pyrylium salt dyes, condensed polycyclic aromatic compounds (anthracene, perylene, etc.), thioxanthone compounds, etc. Examples of electron donors include 4-dimethylaminobenzoic acid esters, 4-dimethylaminotoluene, p-dimethoxybenzene, 1,2,4-trimethoxybenzene, thiophene compounds, etc.

[0057] 6. Regarding Activating Light Absorber (D) When a molded product such as a dental prosthesis is produced with high precision using the curable composition for stereolithography of the present disclosure, in order to prevent excessive transmission of the activating light irradiated from the stereolithography device, which would result in a decrease in the modeling precision of the molded product, 0.01 to 2.5 parts by mass of an activating light absorber (D) that has the function of absorbing the activating light irradiated from the stereolithography device but does not function as a photopolymerization initiator is blended per 100 parts by mass of the polymerizable monomer component.

[0058] If the amount of activating light absorber (D) is too high, the light emitted from the light source of the stereolithography device during the molding process will not pass through the composition, and the condition described in characteristic point [5] will not be satisfied. On the other hand, if the amount of activating light absorber (D) is too low, the precision of the resulting molded object will decrease. For this reason, the amount of activating light absorber (D) is preferably 0.04 to 2.5 parts by mass, more preferably 0.08 to 2.0 parts by mass, and even more preferably 0.25 to 1.0 parts by mass, per 100 parts by mass of the polymerizable monomer component.

[0059] The activated light absorber (D) is not particularly limited as long as it is a compound that absorbs light irradiated from a light source mounted in the stereolithography apparatus, and examples thereof include triazole compounds such as 2-(hydroxy-5-methylphenyl)-2H-benzotriazole and 2-(3-tert-butyl-2-hydroxy-5-methylphenyl)-5-chloro-2H-benzotriazole; and benzophenone compounds such as 2,4-dihydroxybenzophenone and 2-hydroxy-4-methoxybenzophenone.

[0060] 7. Organic-inorganic composite powder / particle (E) As described in characteristic point [3], the composite inorganic filler (B2) occupies 10 to 90 mass %, preferably 20 to 80 mass %, more preferably 30 to 70 mass % of the inorganic filler (B) and is blended as the organic-inorganic composite filler (E).

[0061] Here, the organic-inorganic composite filler refers to a powder or granule composed of particles formed from a composite material of a composite inorganic filler (B2) and a resin (R). Examples of the composite material include a first form in which the composite inorganic filler (B2) is uniformly dispersed in a matrix of the resin (R); and a second form in which the surfaces of the inorganic primary particles forming the composite inorganic filler (B2) are covered with a resin and the inorganic primary particles are bonded to each other by the resin to form (microporous) aggregated particles. The content of the composite inorganic filler (B2) and the resin (R) in the composite material is preferably 50 to 99% by mass, more preferably 70 to 95% by mass. The average particle diameter of the organic-inorganic composite filler (E), specifically, the average particle diameter measured by laser diffraction / scattering, is preferably 0.5 to 100 μm, more preferably 1 to 50 μm, and even more preferably 2 to 30 μm.

[0062] It is well known that the organic-inorganic composite fillers of the first and second embodiments can be produced using inorganic powder and a polymerizable monomer component that is a raw material for the resin (R), and the organic-inorganic composite filler (E) can also be produced using a composite inorganic filler (B2) and a polymerizable monomer component that is a raw material for the resin (R). As the polymerizable monomer component, those exemplified as the polymerizable monomer component (A) are preferably used, but it does not have to be the same as the polymerizable monomer component (A).

[0063] 8. Other Components (Polymerization Inhibitor) In order to improve the storage stability of the curable composition for stereolithography of the present disclosure, a polymerization inhibitor is preferably blended in the range of 0.01 to 5.0 parts by mass relative to 100 parts by mass of the polymerizable monomer component (A). If the blended amount of polymerization inhibitor is too high, the composition will not cure sufficiently during the molding process. On the other hand, if the blended amount of polymerization inhibitor is too low, the storage stability and molding accuracy will decrease. For this reason, the blended amount of polymerization inhibitor is preferably 0.01 to 5.0 parts by mass, more preferably 0.03 to 4.0 parts by mass, and even more preferably 0.05 to 2.5 parts by mass relative to 100 parts by mass of the polymerizable monomer component (A).

[0064] As the polymerization inhibitor, a compound that reacts with radicals generated in the curable composition for stereolithography to deactivate the radicals can be used, and examples thereof include di-tert-butyl-p-cresol and 4-methoxyphenol.

[0065] (Chain Transfer Agent) A chain transfer agent may be blended into the curable composition for stereolithography of the present disclosure in an amount ranging from 0.00001 to 1.0 part by mass per 100 parts by mass of the polymerizable monomer component (A) for the purposes of reducing shrinkage stress during stereolithography and improving modeling accuracy. If the blending amount of the chain transfer agent is too high, the polymerization reaction of the curable composition for stereolithography will be suppressed more than necessary, and if the blending amount of the chain transfer agent is too low, the effect of adding the chain transfer agent will not be obtained.

[0066] Examples of chain transfer agents include thiol compounds such as butanethiol, thiophenol, mercaptoethanol, octylthiol, and lauryl mercaptan; α-alkylstyrene compounds such as 2,4-diphenyl-4-methyl-1-pentene (α-methylstyrene dimer) and 2-phenyl-1-propene (α-methylstyrene); and halogenated hydrocarbons substituted with at least one halogen atom such as carbon tetrachloride and ethylene bromide. Among these, it is preferable to use an α-alkylstyrene compound, particularly α-methylstyrene dimer, because of its high crack suppression effect.

[0067] (Thermal Polymerization Initiator) The curable composition for stereolithography of the present disclosure may contain a thermal polymerization initiator as a polymerization initiator for secondary curing. In this case, it is preferable to use a thermal polymerization initiator with a 10-hour half-life temperature of 50 to 130°C, as it does not function during primary curing but remains effectively in the laminate. Suitable thermal polymerization initiators include organic peroxides such as tert-butyl peroxylaurate and benzoyl peroxide; azo compounds such as azobutyronitrile and azobis(dimethylvaleronitrile); and the like.

[0068] The amount of the thermal polymerization initiator to be added is usually 0.001 to 1.0 part by mass, preferably 0.005 to 0.3 part by mass, and more preferably 0.01 to 0.1 part by mass, per 100 parts by mass of the polymerizable monomer component (A).

[0069] (Coloring Substance) The stereolithography curable composition of the present disclosure may contain a coloring substance within the range satisfying the conditions described in Features [4] and [5]. For example, when the stereolithography curable composition of the present disclosure is used to produce dental restorations such as inlays, onlays, crowns, and dentures, it is preferable to contain a coloring substance to reproduce the color of tooth crowns or the color of oral mucosa. The coloring substance may be a pigment or a dye. Examples of pigments include inorganic pigments such as titanium oxide, zinc oxide, zirconium oxide, zinc sulfide, aluminum silicate, calcium silicate, carbon black, iron oxide, copper chromite black, chromium oxide green, chrome green, violet, chrome yellow, lead chromate, lead molybdate, cadmium titanate, nickel titanium yellow, ultramarine blue, cobalt blue, bismuth vanadate, cadmium yellow, and cadmium yellow; and organic pigments such as monoazo pigments, diazo pigments, diazo condensation pigments, perylene pigments, and anthraquinone pigments.

[0070] 9. Conditions to be Satisfied by Components (A) to (E): Regarding Features [4] and [5] In the curable composition for stereolithography disclosed herein, it is important to satisfy the conditions set forth in Features [4] and [5] in order to reduce the risk of cracking on the surface of the cured product. Specifically, satisfying the condition set forth in Feature [4] makes it easier to satisfy the condition set forth in Feature [5], and satisfying the condition set forth in Feature [5] reduces the risk of cracking on the surface of the cured product. If the condition set forth in Feature [5] is not satisfied, i.e., if the transmittance is less than 1%, sufficient curing depth is not achieved, resulting in the formation of many interlayer low-crosslink density regions and significant cracking. On the other hand, with a composition containing an inorganic filler (B) and an activated light absorber (D), it is extremely difficult to achieve a system with a transmittance of more than 50% while maintaining high modeling accuracy.

[0071] The curable composition for stereolithography disclosed herein has a transmittance for specific activating light within the above range, thereby reducing the effects of scattering and the risk of cracking on the surface of the cured product. To more reliably prevent cracking and enable the production of highly accurate models, the composition is characterized by employing a combination of the polymerizable monomer component (A), the non-composite inorganic filler (B1), and the organic-inorganic composite filler (E) that results in a light-scattering index Sc within a specific range. The curable composition for stereolithography disclosed herein suppresses light scattering by the inorganic filler in directions off the optical axis, and by maintaining the transmittance for specific activating light (before photocuring) within a specific range, cracking can be prevented and, in some cases, modeling accuracy can be further improved.

[0072] The conditions set forth in features [4] and [5] define the conditions that must be satisfied by the polymerizable monomer component (A), inorganic filler (B), photopolymerization initiator (C), activating light absorber (D), and organic-inorganic composite filler (E). The transmittance defined in feature [5] corresponds to the "transmittance of the curable composition for stereolithography of the present disclosure to specific activating light before photocuring" and serves as an indicator of the depth of cure when the curable composition for stereolithography of the present disclosure is irradiated with specific activating light. Furthermore, the Sc defined in feature [4] defines the "scattering state of light when the curable composition for stereolithography of the present disclosure is irradiated with specific activating light," specifically, the state of side-scattered light, and ultimately, the extent of the interlayer low-crosslink density region formed thereby. These cure depths and the state of side-scattered light are important for achieving the effects of the curable composition for stereolithography of the present disclosure and are determined by the combination of the components used. However, because the physical properties of each component that affect transmittance and Sc vary widely and are also affected by their relationships with the physical properties of other components, it is virtually impossible to directly define a specific combination of substances that satisfies these conditions. For this reason, the curable composition for stereolithography of the present disclosure is defined as one that simultaneously satisfies the conditions set forth in features [4] and [5]. Thus, it is virtually impossible to define the curable composition for stereolithography of the present disclosure solely by its composition, such as the components that constitute it and their blending amounts. It must be defined by the parameters set forth in features [4] and [5], or by the curable composition for stereolithography obtained by the manufacturing method of the present disclosure.

[0073] As explained above, satisfying the conditions shown in features [4] and [5] is important from the viewpoint of realizing the effects of the present invention, particularly the crack prevention effect and moderate transparency. Therefore, these features will be explained in detail below.

[0074] 9-1. Regarding Feature [4] It is generally known that when light is irradiated onto fine particles with a particle size suitable for a stereolithography resin composition, i.e., fine particles with a particle size of 0.05 to 5.0 μm, phenomena such as light blocking, diffraction, Mie scattering, and Rayleigh scattering occur. Among these, when Mie scattering and / or Rayleigh scattering occurs, the scattered light spreads not only forward but also to the sides and rear. Furthermore, the scattered light that spreads to the sides (sideward scattered light) reduces the transmittance of the specific activation light in Feature [5], which is thought to cause cracks and further reduce the molding accuracy of the molded product.

[0075] The spread and intensity of side-scattered light, i.e., the intensity distribution of scattered light with respect to the scattering direction (angle), are affected not only by the particle size of the particles but also by the refractive index of the particles and the polymerizable monomer component (which serves as a dispersion medium) surrounding the particles. However, in a dispersion system in which particles are dispersed in a polymerizable monomer component as a powder with a particle size distribution, particularly in a dispersion system composed of multiple types of particles with different refractive indices, it is virtually impossible to grasp the scattering behavior of each particle, and it is necessary to grasp the scattering behavior of the entire system. Furthermore, when the curable composition for stereolithography disclosed herein is used to manufacture dental prosthetic materials, the greater the average "intensity of side-scattered activation light" of the entire system, the lower the modeling accuracy, and further the transmittance of the specific activation light, which may lead to concerns about the occurrence of cracks due to the expansion of interlayer low-crosslink density regions. For these reasons, in the present disclosure, the combination of the polymerizable monomer, non-composite inorganic filler, and organic-inorganic composite filler used in the curable composition for stereolithography of the present disclosure is indirectly defined by using the light scattering index: Sc (%) defined by the above formula in the base composition (which is a homogeneous base composition consisting only of a polymerizable monomer, a non-composite inorganic filler, and an organic-inorganic composite filler in a predetermined quantitative ratio) that serves as the base of the curable composition for stereolithography of the present disclosure.

[0076] Measurement of refracted light passing through a sample using a goniophotometer is used to evaluate the optical properties of materials that require light diffusion, such as lighting fixture covers and projector screens. In the dental field, as described in Patent Document 5, it is also used as an index for evaluating the optical texture of tooth filling and restorative materials, specifically, to determine the diffusion index D.

[0077] In the present disclosure, measurements using a goniophotometer to determine the light scattering index Sc can be performed as follows. First, a portion of the base composition (for raw materials) prepared during the preparation process of the curable composition for stereolithography of the present disclosure is sampled, or a base composition (for measurement) prepared by separately preparing the base composition is used to prepare a measurement sample with a thickness of 0.5 mm in the same manner as in transmittance measurements. Next, the sample is placed in a three-dimensional goniophotometer (e.g., GP-200, manufactured by Murakami Color Research Laboratory Co., Ltd.), and measurement light containing light of a specific wavelength λ (nm), primarily composed of light within a range of λ±50 (nm) and exhibiting maximum intensity within that range is irradiated perpendicularly onto the sample, and the intensity of the transmitted light at each emission angle is measured. Note that if the light emitted from the light source (capable of emitting light containing light of wavelength λ) attached to the three-dimensional goniophotometer does not satisfy the above-mentioned conditions for the measurement light, an interference filter (e.g., for the GP-200, manufactured by Murakami Color Research Laboratory Co., Ltd.) can be used to generate measurement light that satisfies the above-mentioned conditions. In addition, the fact that light within the range of λ±50 (nm) is the main component means that in the spectrum showing the wavelength distribution (relative spectral distribution) of the measurement light, the integrated value of the intensity of light with wavelengths of λ±50 (nm) is 90% or more of the integrated value of the intensity of the entire measurement light.

[0078] When the light-scattering index Sc of the base composition exceeds 10%, the formation of interlayer low-crosslink density regions that cause cracking due to side-scattered light is unavoidable. From the viewpoint of preventing cracking and improving molding accuracy, the light-scattering index Sc of the base composition is preferably 5.0% or less, and more preferably 3.0% or less. The lower the light-scattering index Sc, the better, with the lower limit being 0.0%.

[0079] The light-scattering index Sc of the base composition is affected by the blending ratio of the polymerizable monomer component (A), the non-composite inorganic filler (B1), and the organic-inorganic composite filler (E). However, when the ratio is constant, it can be controlled to some extent by adjusting the particle size distribution of the non-composite inorganic filler (B1) and the composite inorganic filler (B2) in the organic-inorganic composite filler (E), the refractive index (or type) of the particles constituting the inorganic powder or granule, as well as the refractive index of the entire polymerizable monomer component and the refractive index of the resin (R) in the organic-inorganic composite filler (E).

[0080] For example, regarding particle size, there is known a parameter called "particle size parameter: α" which is an index of the scattering of light caused by particles and the scattering intensity. This particle size parameter α is calculated by dividing the wavelength (nm) of incident light by λ ０ When the ratio of the circumference of a circle to its circumference is π and the particle diameter of the inorganic particles is x (nm), the formula: α=(π×x) / λ ０ When particles are transparent to incident light, diffraction occurs when the particle size parameter α exceeds 10, and Mie scattering or Reyleigh scattering occurs when the particle size parameter α is 10 or less. When a laser beam with a wavelength of 405 nm, which is the most common activation light in the liquid tank photopolymerization method, is used, x = α λ ０ From the relationship of / π, the particle diameter x at which α = 10 is 1290 nm = 1.29 μm, and when a laser beam with a wavelength of 385 nm is used, the particle diameter x at which α = 10 is 1226 nm = 1.23 μm. Since many dental inorganic fillers have particle diameters smaller than this value, the above-mentioned scattering occurs, and cracks are likely to occur.

[0081] According to the studies of the present inventors, even when Mie scattering or Reyleigh scattering occurs, the light-scattering index Sc tends to decrease as the proportion of particles whose particle size parameter α is in the range of 0.7 to 4 in the particle size distribution measured by microscopy using a scanning microscope, that is, particles satisfying the relationship x = 0.7 × (λ / π) to 4 × (λ / π) (when the wavelength of the activating light is 405 nm, x = 90 to 514 nm, and when the wavelength of the activating light is 385 nm, x = 86 to 490 nm), increases. For the reason that it becomes easier to keep the light-scattering index Sc at 10% or less, the inorganic filler (B), i.e., the non-composite inorganic filler (B1) and the composite inorganic filler (B2) used, preferably satisfy the following condition 1:

[0082] Condition 1: When the particle diameter of each primary particle constituting the inorganic filler (B) is x (nm) and pi is π, in the particle size distribution of the inorganic filler (B) measured by a microscopy method using a scanning microscope, the total number of particles having a particle diameter x (nm) in the range of 0.7λ / π to 4λ / π (nm) is 40% or more, preferably 60% or more, and more preferably 80% or more of the total number of primary particles constituting the inorganic filler (B).

[0083] Furthermore, for the reason that it is easier to satisfy the condition in characteristic point [4], in the particle size distribution measured by a microscopy method using a scanning microscope, the proportion of particles having a particle diameter in which the particle diameter parameter α is in the range of 1.0 to 3.0 (129 to 386 nm when the wavelength of the activating light is 405 nm) in the inorganic filler (B) is preferably 50% or more, more preferably 60% or more, and the proportion of particles having a particle diameter in which the particle diameter parameter α is in the range of 1.8 to 2.8 (231 to 360 nm when the wavelength of the activating light is 405 nm) is even more preferably 45% or more, particularly preferably 50% or more.

[0084] In addition, since commonly used stereolithography devices (3D printers) use a light source with an activation light wavelength (peak wavelength) of 380 to 420 nm, in order to simultaneously satisfy the conditions shown in features [4] and [5], in the particle size distribution measured by microscopy using a scanning microscope, the total number of particles having a particle diameter in the range of 85 to 535 nm is preferably 40% or more of the total number of primary particles constituting the inorganic filler (B), more preferably 60% or more, and even more preferably 80% or more. A more preferred particle diameter range is 121 to 400 nm, and an even more preferred particle diameter range is 218 to 375 nm. In other words, in the particle size distribution measured by microscopy using a scanning microscope, the total number of particles having a particle diameter in the range of 218 to 375 nm is most preferably 80% or more of the total number of primary particles constituting the inorganic filler (B).

[0085] Furthermore, the smaller the difference between the refractive index of the particles and the refractive index of the polymerizable monomer component, the smaller the light scattering index Sc tends to be. Considering the refractive index of the inorganic filler and the refractive index of the polymerizable monomer component used in dentistry, it is preferable to adopt a combination of the inorganic filler (B) and the polymerizable monomer component (A) that satisfies the following conditions 2 to 4.

[0086] Condition 2: The refractive index of the inorganic powder particles constituting the inorganic filler (B) at 25°C for the (sodium) D line: n （Ｄ）ＦWhen inorganic powder particles (b1) are inorganic powder particles consisting of an aggregate of a single type of inorganic particles having a refractive index in the range of 1.500 to 1.550, and inorganic powder particles (b2) are inorganic powder particles consisting of an aggregate of a single type of inorganic particles having a refractive index outside the above range, the non-composite inorganic filler (B1) and the composite inorganic filler (B2) are each: (1) composed of a single type of specific inorganic powder particle (b1), or (2) composed of a plurality of types of specific inorganic powder particle (b1), and at least one of the plurality of types of specific inorganic powder particle (b1) accounts for 10 mass% or more of the total mass of each of the non-composite inorganic filler (B1) and the composite inorganic filler (B2), or (3) It is composed of a single type or multiple types of specific inorganic powder or particles (b1): 90 mass% or more but less than 100 mass% and a single type or multiple types of non-specific inorganic powder or particles (b2): more than 0 mass% but 10 mass% or less, and at least one of the single type or multiple types of specific inorganic powder or particles (b1) accounts for 10 mass% or more of the total mass of each of the non-composite inorganic filler (B1) and the composite inorganic filler (B2).

[0087] Condition 3: refractive index of polymerizable monomer component (A) at 25°C with respect to D line: n （Ｄ）Ｍ is in the range of 1.490 to 1.550.

[0088] Condition 4: The refractive index at 25°C of at least one specific inorganic powder or particle (b1) that accounts for 10 mass% or more of the total mass of each of the non-composite inorganic filler (B1) and the composite inorganic filler (B2) with respect to the D line is: n （Ｄ）Ｆ Of these, n （Ｄ）Ｍ The refractive index where the difference between （Ｄ）Ｆｈ When （Ｄ）Ｆｈ and （Ｄ）Ｍ Absolute value of the difference with: |n （Ｄ）Ｆｈ -n （Ｄ）Ｍ | is 0.035 or less.

[0089] Above |n （Ｄ）Ｆｈ -n （Ｄ）ＭWhen | increases, the refraction of the activating light at the interface between the inorganic filler and the polymerizable monomer component increases, the intensity of the side scattered light increases, and the light scattering index Sc tends to increase, and when the proportion of particles whose particle diameter is significantly smaller than the wavelength of the activating light increases, Rayleigh scattering tends to occur, and the light scattering index Sc tends to increase. Conversely, when the proportion of particles whose particle diameter is significantly larger than the wavelength of the activating light increases, the frequency with which the activating light collides with the inorganic filler increases significantly, and the light scattering index Sc tends to increase.

[0090] The refractive index of the inorganic filler (B) composed of a single material (non-composite inorganic filler (B1) and composite inorganic filler (B2)) at 25°C for the D line is: n （Ｄ）Ｆ and the refractive index of the polymerizable monomer component at 25°C for the D line: n （Ｄ）Ｍ can be measured as follows:

[0091] That is, the refractive index of the polymerizable monomer component: n （Ｄ）Ｍ can be measured by using an Abbe refractometer (for example, Digital Abbe refractometer DR-A1-PLUS manufactured by Atago Co., Ltd.), placing the prepared monomer composition on a prism, looking into the sample through an eyepiece, and reading the value on the display when the boundary line and the cross line intersect (this value is the refractive index). In addition, the refractive index of the inorganic powder particles constituting the inorganic filler: n （Ｄ）Ｆ is determined by mixing toluene or ethanol with bromonaphthalene to prepare solutions with refractive indices varying in increments of 0.001, then mixing each inorganic powder or particle with each solution with a different refractive index and shaking the mixture, and determining the refractive index of the solution that is observed to be the most transparent as the refractive index of that inorganic powder or particle.

[0092] 9-2. Regarding Feature [5]: The curable composition for stereolithography of the present disclosure must have a transmittance of 1 to 50% for specific activating light measured on a 0.5 mm thick sample. This transmittance serves as an indicator of the depth of cure. If the transmittance is lower than the lower limit of 1%, sufficient cure depth cannot be achieved, making stereolithography difficult. Even if stereolithography is possible, cracks are likely to occur in the model. Furthermore, in systems containing 40 parts by mass or more of inorganic filler (B) per 100 parts by mass of polymerizable monomer component (A) and containing a polymerization initiator in an amount sufficient for stereolithography, it is difficult to achieve a transmittance significantly exceeding the upper limit of 50%. Furthermore, even within the achievable transmittance range, excessive irradiation with specific activating light can cause excessive curing reactions, resulting in molded products with shapes completely different from those represented by CAD data. From the perspectives of preventing cracking and improving the shape of the molded products, the transmittance is preferably 2 to 30%, and more preferably 5 to 20%.

[0093] Since the curable composition for stereolithography according to the present disclosure contains a photopolymerization initiator, there is a concern that curing may proceed due to light irradiation during measurement. In this regard, by using a transmittance measurement method using a color difference meter as described below, it is possible to measure the transmittance of specific activating light before curing proceeds.

[0094] The transmittance of the photocurable composition for stereolithography of the present disclosure to activating light can be measured as follows. First, a 0.5 mm-thick measurement sample is prepared by filling a resin mold (25 mm x 25 mm x 0.5 mm thick) with the photocurable resin composition of the present disclosure, pressing the top and bottom surfaces of the mold with glass slides, reducing the thickness to 0.5 mm, and then removing the glass slide. Next, the measurement sample is placed in a color difference meter (e.g., a spectrophotometer SE7700 manufactured by Nippon Denshoku Industries Co., Ltd.), and the transmittance of a specific activating light (e.g., 405 nm wavelength light or 385 nm wavelength light) is measured by transmission measurement using a measurement light source from a halogen lamp (measurement wavelength: 380 to 780 nm).

[0095] The transmittance tends to be higher as the light transmittance of the resin (R) constituting the polymerizable monomer component (A), inorganic filler (B), and organic-inorganic composite filler (E) itself increases. The transmittance also tends to be higher as the difference between the refractive index of the inorganic filler (B) to the specific activating light and the refractive index of the polymerizable monomer component (A), the difference between the refractive index of the resin (R) to the specific activating light and the refractive index of the polymerizable monomer component (A), and the difference between the refractive index of the inorganic filler (B) to the specific activating light and the refractive index of the resin (R) to the specific activating light decreases. Furthermore, when the light transmittances of the polymerizable monomer component (A), inorganic filler (B), and resin (R) differ, the blending ratios affect the transmittance. Generally, the transmittance of the polymerizable monomer component and resin is significantly higher than 5%, so long as the blending amount of inorganic filler is within the specified range, using a light-transmitting inorganic filler and reducing the refractive index difference makes it possible to achieve a transmittance of 1% or more, and even 3% or 5% or more.

[0096] For the reason that the condition in characteristic point [5] is easily satisfied, it is preferable that the polymerizable monomer component (A), the inorganic filler (B), and the resin (R) satisfy the following condition 5.

[0097] Condition 5: The refractive index of at least one specific inorganic powder or particle (b1) that accounts for 10% by mass or more of the total mass of the non-composite inorganic filler (B1) and the composite inorganic filler (B2) at 25°C with respect to specific activating light: n （ＡＬ）Ｆ and the refractive index of the polymerizable monomer component (A) at 25°C with respect to specific activating light: n （ＡＬ）Ｍ and the refractive index of the resin (R) at 25°C with respect to a specific activating light: n （ＡＬ）Ｒ and the following (i) to (iii): −0.015<(n （ＡＬ）Ｆ -n （ＡＬ）Ｍ )<0.025 (i) -0.015<(n （ＡＬ）Ｒ -n （ＡＬ）Ｍ )<0.030 (ii) -0.020<(n （ＡＬ）Ｆ -n （ＡＬ）Ｒ ) <0.020 (iii) All of the conditions shown in (iii) are satisfied.

[0098] In condition 5, the following (ia) to (iiia): −0.012<(n （ＡＬ）Ｆ -n （ＡＬ）Ｍ )<0.022 (ia) -0.010<(n （ＡＬ）Ｒ -n （ＡＬ）Ｍ )<0.022 (iia) -0.020<(n （ＡＬ）Ｆ -n （ＡＬ）Ｒ )<0.017 (iiia) is preferably satisfied.

[0099] In addition, the following (ib) to (iiib): −0.005<(n （ＡＬ）Ｆ -n （ＡＬ）Ｍ )<0.015 (ib) -0.005<(n （ＡＬ）Ｒ -n （ＡＬ）Ｍ )<0.018 (iib) -0.014<(n （ＡＬ）Ｆ -n （ＡＬ）Ｒ )<0.005 (iiib) It is more preferable that all of the conditions shown in (iiib) be satisfied.

[0100] 10. Method for Producing the Curable Composition for Stereolithography of the Present Disclosure To produce the curable composition for stereolithography of the present disclosure, the substances exemplified in items 3 to 8 may be used, and the components may be mixed so that the composition ratios of the essential components fall within the above-described ranges to form a uniform liquid composition. However, it is necessary to satisfy the conditions set forth in characteristics [4] and [5].

[0101] The method for producing a curable composition for stereolithography according to the present disclosure is characterized by using a combination of the polymerizable monomer component (A), inorganic filler (B), photopolymerization initiator (C), activated light absorber (D), and organic-inorganic composite filler (E) that satisfies the above-mentioned conditions. By employing this production method, the curable composition for stereolithography according to the present disclosure can be easily produced.

[0102] That is, the method for producing a curable composition for stereolithography according to the present disclosure is a method for producing a curable composition for stereolithography according to the present disclosure, and includes a mixing step of mixing a polymerizable monomer component (A), a non-composite inorganic filler (B1), an organic-inorganic composite filler (E), a photopolymerization initiator (C), and an activated light absorber (D); In the mixing step, the polymerizable monomer component (A), the non-composite inorganic filler (B1), and the organic-inorganic composite filler (E) satisfy all of the above-mentioned conditions 1 to 5, and when a composition consisting only of the polymerizable monomer component (A), the non-composite inorganic filler (B1), and the organic-inorganic composite filler (E) is used as a base composition, in which the compositional ratio of these components is the same as that of the curable composition for stereolithography that is the target of production, a measurement is performed using a goniophotometer in which a measurement light containing light of a specific wavelength: λ (nm), containing light mainly within a range of λ±50 (nm) and exhibiting the maximum intensity within that range is irradiated perpendicularly to the base composition, and the light scattering index: Sc (%), determined based on the intensity of the transmitted light in a specific output angle direction obtained by the measurement, is 10 (%) or less (condition 6).

[0103] The components are preferably mixed using a stirrer under the shielding of light that activates the photopolymerization initiator, for example, under red light, at room temperature until homogeneous, and after mixing, it is preferable to perform a degassing treatment.

[0104] 11. Method for producing a three-dimensional stereolithography object and method for producing a dental restoration according to the present disclosure The method for producing a three-dimensional stereolithography object according to the present disclosure is a method for producing a three-dimensional object by liquid vat photopolymerization, which includes the above-described molding step, washing step, and secondary curing step, and is characterized in that the curable composition for stereolithography according to the present disclosure is used as the liquid photocurable composition supplied to the tank of the liquid vat photopolymerization device. Because the method for producing a three-dimensional stereolithography object according to the present disclosure uses the curable composition for stereolithography according to the present disclosure, it is possible to produce a three-dimensional stereolithography object that has high mechanical strength and is free of cracks on its actual surface.

[0105] In the method for producing a three-dimensional optically shaped object of the present disclosure, the molding process includes: a first step of irradiating a predetermined position of a liquid photocurable composition held in a tank with activating light based on two-dimensional shape data at a height of an initial ranking order, thereby curing the composition, and forming a modeling layer having a shape corresponding to the two-dimensional shape data, and using the modeling layer as a bonded layer; a second step of moving the bonded layer up or down and supplying a liquid photocurable composition immediately above or below the bonded layer in the tank; a third step of irradiating a predetermined position of the liquid photocurable composition supplied immediately above or below the bonded layer based on two-dimensional shape data at a height next in the ranking order in the previous step with activating light, thereby curing the liquid photocurable composition, and forming a new modeling layer having a shape corresponding to the two-dimensional shape data, and bonding the new modeling layer to the bonded layer, thereby obtaining a laminate having the new modeling layer as a new bonded layer; and a fourth step of moving the laminate up or down and supplying a liquid photocurable composition immediately above or below the new bonded layer in the tank. It is preferable that the new bonded layer is used as the bonded layer in the third step, and the cycle consisting of the third step and the fourth step is repeated, and in the final third step, a new modeling layer is formed based on the two-dimensional shape data at the height of the final ranking order to obtain a laminate.

[0106] Such a liquid vat photopolymerization method including a molding step can be suitably carried out using a commercially available liquid vat photopolymerization device known as a 3D printer.

[0107] In the method for manufacturing a three-dimensional optically shaped object according to the present disclosure, after the molding step, the obtained laminate is washed with an organic solvent (a washing step is performed), and then the laminate is subjected to secondary curing by additional irradiation with activating light, heat treatment, or both (a secondary curing step is performed).

[0108] Examples of organic solvents used in the washing step include alcohol-based solvents such as ethanol, methanol, and isopropyl alcohol; ketone-based solvents such as acetone and methyl ethyl ketone; ether-based solvents such as diethyl ether, diisopropyl ether, tripropylene glycol monomethyl ether, and tetrahydrofuran; amide-based solvents such as N-methylpyrrolidone and dimethylacetamide; and halogen-based solvents such as methylene chloride and chloroform. Among these, alcohol-based solvents and ether-based solvents are preferred because of their high washing efficiency, and alcohol-based solvents are more preferred because of their low environmental impact.

[0109] The wavelength of the additional activating light irradiation in the secondary curing step is not particularly limited as long as it is a wavelength that can be absorbed by the photopolymerization initiator remaining in the laminate to generate radicals. The irradiation intensity of the additional activating light irradiation is 5 mW / cm or less so that the photopolymerization initiator remaining in the laminate generates a sufficient amount of radicals. ２ It is preferable that the power is 10 mW / cm or more. ２ More preferably, it is 30 mW / cm or more. ２ It is more preferable that the irradiation intensity is 10,000 mW / cm or more. The irradiation time is not particularly limited, and is preferably 1 minute or more, more preferably 3 minutes or more, and even more preferably 5 minutes or more. If the irradiation intensity during the additional activation light irradiation is too strong, the molded object may be overheated, which may cause cracks in the molded object. Therefore, the irradiation intensity should be 10,000 mW / cm or more. ２ It is preferable that:

[0110] Furthermore, when a thermal polymerization initiator is blended into the curable composition for stereolithography according to the present disclosure, the secondary curing can be carried out by heating the composition at a temperature of preferably 45 to 120°C, more preferably 50 to 90°C, and even more preferably 55 to 80°C.

[0111] The method for manufacturing a dental restoration according to the present disclosure is characterized in that dental restorations such as inlays, onlays, crowns, and dentures are manufactured using the method for manufacturing a three-dimensional optically shaped object according to the present disclosure. When manufacturing such dental restorations, CAD data designed based on digital data obtained by scanning the intraoral shape of an individual patient or an intraoral model created for each individual patient can be used as three-dimensional shape data indicating the shape of the dental restoration (three-dimensional object) used in the molding process. The method for manufacturing a dental restoration according to the present disclosure can manufacture dental restorations that have high mechanical strength and are free of cracks on their actual surfaces.

[0112] The present invention will be explained in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples.

[0113] The compounds and their abbreviations used below are as follows:

[0114] (1) Polymerizable Monomer Component (A) (Monomer Compound) UDMA: urethane dimethacrylate 3G: triethylene glycol dimethacrylate D-2.6E: bisphenol A ethylene glycol (EO) adduct dimethacrylate (number of EOs added: average 2.6) ACMO: acryloylmorpholine 8FHD: octafluorooctanediol dimethacrylate

[0115] (Monomer Composition) As the monomer composition, monomer compositions A1 to A15 were used, which were prepared by mixing the above-mentioned monomer compounds in the compositions shown in the following Table 1. The values ​​in parentheses in the following Table 1 indicate the content (% by mass) of each monomer compound.

[0116]

[0117] The refractive index of each monomer composition with respect to the D line at 25°C is: n （Ｄ）Ｍ and the refractive index of each monomer composition with respect to activation light having a wavelength of 405 nm at 25° C.: n （ＡＬ）Ｍis a value measured by placing each sample on the prism of a digital Abbe refractometer (DR-M2, manufactured by Atago Co., Ltd.), using an interference filter that selectively transmits the measurement light (D-line or light with a wavelength of 405 nm), looking into the sample through an eyepiece, and reading the value on the display when the boundary line and the cross line intersect.

[0118] (2) Inorganic Filler (B) The inorganic powders shown below were used as they were or in combination with other inorganic fillers B-1 to B-8 to obtain the compositions shown in Table 2. SZ-1: Average primary particle diameter 280 nm, refractive index n （Ｄ）Ｆ = 1.522, n （ＡＬ）Ｆ = 1.559 spherical silica-zirconia (surface treated with γ-methacryloyloxypropyltrimethoxysilane) SZ-2: average primary particle diameter 150 nm, refractive index n （Ｄ）Ｆ = 1.522, n （ＡＬ）Ｆ = 1.559 spherical silica-zirconia (surface treated with γ-methacryloyloxypropyltrimethoxysilane) SZ-3: average primary particle diameter 450 nm, refractive index n （Ｄ）Ｆ = 1.540, n （ＡＬ）Ｆ = 1.578 spherical silica-zirconia (surface treated with γ-methacryloyloxypropyltrimethoxysilane) SB-1: average primary particle diameter 700 nm, refractive index n （Ｄ）Ｆ = 1.530, n （ＡＬ）Ｆ = 1.569 amorphous barium glass filler (GM27884 manufactured by Schott; surface treated with γ-methacryloyloxypropyltrimethoxysilane) SB-2: average primary particle diameter 200 nm, refractive index n （Ｄ）Ｆ = 1.530, n （ＡＬ）Ｆ = 1.569 amorphous barium glass filler (GM27884 manufactured by Schott; surface treated with γ-methacryloyloxypropyltrimethoxysilane) SO-1: average primary particle diameter 1000 nm, refractive index n （Ｄ）Ｆ = 1.450, n （ＡＬ）Ｆ = 1.496 spherical silica (surface treated with γ-methacryloyloxypropyltrimethoxysilane)

[0119] The refractive index of each inorganic powder is n （Ｄ）Ｆ and n（ＡＬ）Ｆ is a value measured by the following method: That is, ethanol or toluene and bromonaphthalene were mixed to prepare solutions with different refractive indices in increments of 0.001, and then inorganic powder particles were mixed with each solution with different refractive indices to prepare mixed solutions of inorganic powder particles, which were then shaken, and the refractive index of the solution that was observed to be the most transparent was measured in the same manner as in the measurement of the refractive index of the monomer composition, and the refractive index n of the inorganic powder particles was determined. （Ｄ）Ｆ In addition, when the mixed solution was irradiated with activating light (light with a wavelength of 405 nm), the refractive index of the solution in which the activating light was most clearly observed was measured in the same manner as in the measurement of the refractive index of the monomer composition, and the refractive index n of the inorganic powder and granules was determined. （ＡＬ）Ｆ It was decided.

[0120] In addition, the content of particles having a particle diameter of 0.05 to 5.0 μm relative to the total particles constituting each inorganic filler was measured from the particle size distribution determined by microscopy using a scanning microscope (referred to as the "specific particle content" in Table 2). Furthermore, for each inorganic filler, the content of particles having a (primary) particle diameter within a specific range of particle diameter parameter α (referred to as the "α-sufficient particle content" in Table 2) was determined from the particle size distribution determined by microscopy using a scanning microscope. Specifically, the content of particles having a particle diameter parameter α in the range of 0.7 to 4.0: R1 (%), the content of particles having a particle diameter parameter α in the range of 1.0 to 3.0: R2 (%), and the content of particles having a particle diameter parameter α in the range of 1.8 to 2.8: R3 (%) were determined. The results are also shown in Table 2. The particle size distribution is calculated by the number of all particles (50 or more) observed in a unit field of view in a scanning electron microscope photograph of each inorganic filler: n (number), and the primary particle diameter (maximum diameter) of all particles: X ｉ (nm) was measured.

[0121]

[0122] (3) Organic-inorganic composite filler Organic-inorganic composite fillers CF1 to CF9 were prepared in the same manner as in Example 1 of Patent Document 4 (WO 2013 / 039169), except that the inorganic powder and granules shown in Table 3 below and the monomer composition having the composition shown in Table 3 below were used as the polymerizable monomer components serving as raw materials for the composite inorganic filler (B2) and resin (R) constituting the organic-inorganic composite filler. The numbers in parentheses in Table 3 below indicate the content (% by mass) of each monomer compound. In the organic-inorganic composite particles constituting these organic-inorganic composite fillers, the cured product of the monomer composition becomes the resin (R), which covers the surfaces of the inorganic primary particles that become the composite inorganic filler (B2) and bonds the inorganic primary particles to each other to form a composite.

[0123] The refractive index n in Table 3 （ＡＬ）Ｒ is a value measured by placing a 0.1 mm thick cured product of the monomer composition on the prism of a digital Abbe refractometer (DR-M2, manufactured by Atago Co., Ltd.), using an interference filter that selectively transmits measurement light (light with a wavelength of 405 nm), looking into the sample through an eyepiece, and reading the value on the display when the boundary line and the intersection of the cross lines are aligned.

[0124]

[0125] (4) Photopolymerization initiator BAPO: phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide (generates radicals when irradiated with activation light having a wavelength of 405 nm) TPO: 2,4,6-trimethylbenzoyl-diphenylphosphine oxide CQ: camphorquinone DMBE: dimethyl p-ethoxybenzoate

[0126] (5) Activated Light Absorber SS3: 2-(3-tert-butyl-2-hydroxy-5-methylphenyl)-5-chloro-2H-benzotriazole

[0127] (6) Polymerization inhibitors BHT: dibutylhydroxytoluene HQME: hydroquinone methyl ether

[0128] (7) Coloring substance Titanium oxide (average primary particle diameter: 200 μm)

[0129] I. Reference Examples and Comparative Examples As described above, the curable composition for stereolithography disclosed herein belongs to the category of previously proposed curable compositions. The previously proposed curable compositions have the advantage of enabling the production of three-dimensional stereolithography objects with excellent mechanical strength and shape accuracy while minimizing the risk of decreased fluidity and sedimentation of inorganic fillers and preventing the occurrence of cracks on the surface. Therefore, this point will be explained first with reference to the following Reference Examples and Comparative Examples.

[0130] Reference Example 1 (1) Preparation of base composition for Sc evaluation and curable composition for stereolithography To 100 parts by mass of a polymerizable monomer component consisting of monomer composition A1 (50 parts by mass of UDMA, 20 parts by mass of 3G, and 30 parts by mass of D-2.6E), 150 parts by mass of B-1 as a non-composite inorganic filler (B1) was added, and the mixture was stirred and mixed until homogeneous, followed by degassing to prepare a base composition for Sc evaluation.

[0131] Separately, a raw material base composition was prepared in the same manner, to which was added 1.4 parts by mass of a photopolymerization initiator consisting of BAPO, 0.7 parts by mass of an activated light absorber consisting of SS3, and a total of 0.2 parts by mass of a polymerization inhibitor consisting of 0.1 parts by mass of HQME and 0.1 parts by mass of BHT (all of these blending amounts are based on 100 parts by mass of the polymerizable monomer component), and the mixture was stirred and mixed under red light until uniform, followed by degassing to prepare a liquid curable composition for stereolithography.

[0132] (2) Measurement of Light Scattering Index Sc The base composition for Sc evaluation was filled into a PTFE mold (25 mm x 25 mm x 0.5 mm thick). The top and bottom surfaces were pressed against each other with glass slides, and the thickness of the composition was adjusted to 0.5 mm. The glass slides were then removed to prepare an evaluation sample. This evaluation sample was set in a three-dimensional goniophotometer (GP-200, manufactured by Murakami Color Research Laboratory Co., Ltd.), and measurement light was irradiated perpendicularly onto the evaluation sample to measure the luminous intensity distribution of the transmitted light. For the measurement, an interference filter (for GP-200, manufactured by Murakami Color Research Laboratory Co., Ltd.) was installed between the light source of the three-dimensional goniophotometer and the evaluation sample, and light having the wavelength distribution (relative spectral distribution) shown in Figure 5 was used as the measurement light. Based on the obtained luminous intensity distribution, the following equation: Sc = {(I７０ +I ７５ +I ８０ ) / (I ０ × 3)} × 100. As a result, the light scattering index Sc was found to be 0.1%.

[0133] (3) Measurement of Activation Light Transmittance The stereolithography curable resin composition obtained in (1) above was filled into a PTFE resin mold (25 mm x 25 mm x 0.5 mm thick). The top and bottom surfaces were pressed with glass slides to adjust the thickness of the composition to 0.5 mm, and then the glass slides were removed to obtain a resin composition with a thickness of 0.5 mm. The transmittance of this resin composition at a wavelength of 405 nm was measured using a color difference meter (Spectrophotometer SE7700, manufactured by Nippon Denshoku Industries Co., Ltd.). The result was a transmittance of 5.3%.

[0134] (4) Production of three-dimensional objects The stereolithography curable composition obtained in (1) above was supplied to the resin tray (tank) of a 3D printer (DWS, DW029D; wavelength: 405 nm, irradiation intensity: 83 mW), and a molding process was performed using 10 mm x 10 mm x 25 mm rectangular parallelepiped stereolithography data (hereinafter abbreviated as "stl data"). A molded body (composed of a cured product of the stereolithography curable composition) having a laminated structure (laminate) was produced. Next, the obtained molded body was immersed in a plastic container filled with ethanol for 15 minutes, gently shaken, and washed, then dried, and further irradiated with additional light (secondary curing) using a UV CURING UNIT UVIS-2 (DWS) for 30 minutes to produce a three-dimensional stereolithography object.

[0135] (5) Evaluation of 3D stereolithography The 3D stereolithography obtained in (4) above was used as an evaluation sample, and was subjected to evaluation of molding accuracy, crack evaluation, and a three-point bending fracture strength test. The evaluation methods and results are shown below.

[0136] (Evaluation of molding accuracy) The length of each side of the evaluation sample was measured to the nearest 0.01 mm, and the measured value was divided by the set value at the time of molding (the length of each side set in the STL data) to obtain the value "actual measurement value / STL data set value" for each side, and the average value was evaluated as the average molding accuracy. As a result, the average molding accuracy was "1.01".

[0137] (Crack Evaluation) The surface of the evaluation sample was observed with an optical microscope (50x magnification), and the same evaluation sample was also platinum coated to a thickness of 5 nm and then observed with a scanning microscope (1000x magnification). The number and width of cracks observed on one surface of a 10 mm x 25 mm area of ​​the evaluation sample were confirmed and evaluated according to the following evaluation criteria. As a result, the crack evaluation result was "A1". -Evaluation Criteria- A0: No cracks were observed on the surface of the cured body. A1: The number of cracks observed on the surface of the cured body was 5 or less, and each crack width was 10 μm or less, which is within the acceptable range. A2: The number of cracks observed on the surface of the cured body was 10 or less, and each crack width was 10 μm or less, which is within the acceptable range. A3: The number of cracks observed on the surface of the cured body was 20 or less, and each crack width was 10 μm or less, which is within the acceptable range. B: The number of cracks observed on the surface of the cured body was 20 or less, and each crack width was 10 to 40 μm. C: 20 or more cracks with a width of 10 to 40 μm are observed on the surface of the cured body. D: A large number of cracks with a width of 40 μm or more are observed on the surface of the cured body.

[0138] Reference Examples 2 to 14 and Reference Comparative Examples 1 to 8 Base compositions for Sc evaluation and curable compositions for stereolithography were prepared in the same manner as in Reference Example 1, except that the components and amounts used when preparing the base composition for Sc evaluation and the curable composition for stereolithography in Reference Example 1 were changed as shown in Tables 4 and 5. Each of the resulting compositions was then evaluated in the same manner as in Reference Example 1, and three-dimensional stereolithography objects were produced and evaluated using the resulting curable compositions for stereolithography in the same manner as in Reference Example 1. The evaluation results are shown in Tables 6 and 7. Optical microscope images (magnification: 50x) taken during crack evaluation for Reference Example 7 (evaluation A0), Reference Example 11 (evaluation A2), and Reference Comparative Example 1 (evaluation D) are shown in Figures 1, 2, and 3, respectively.

[0139] Comparative Example 9: A curable composition for stereolithography was prepared according to the method described in Example 1 of Patent Document 3. Specifically, the polymerizable monomer component (A) and inorganic filler (B) shown in Table 5 were used in the blending ratios shown in Table 5, and 3.0 parts by mass of a polymerization initiator consisting of TPO and 0.05 parts by mass of a polymerization inhibitor consisting of BHT (all blending amounts are relative to 100 parts by mass of the polymerizable monomer component) were added to prepare a curable composition for stereolithography. A three-dimensional object was then manufactured and evaluated using the resulting curable composition for stereolithography in the same manner as in Reference Example 1. A base composition for Sc evaluation and an uncured composition (for transmittance evaluation) were also prepared in the same manner as in Reference Example 1, and each composition was evaluated in the same manner as in Reference Example 1. The evaluation results are shown in Table 7. An optical microscope image (magnification: 50x) taken during crack evaluation of Comparative Example 9 (Evaluation C) is shown in Figure 4.

[0140]

[0141]

[0142]

[0143]

[0144] As shown in Table 6, the curable compositions for stereolithography of Reference Examples 1 to 14 had a small light scattering index Sc and a high activation light transmittance, resulting in high modeling accuracy and suppressed cracking.

[0145] On the other hand, as shown in Table 7, the stereolithography curable compositions of Reference Comparative Examples 1 to 3 had a high light scattering index Sc and a low activation light transmittance, resulting in low modeling accuracy and cracking. Furthermore, the stereolithography curable compositions of Reference Comparative Examples 4 to 7 had a low light scattering index Sc but a low activation light transmittance, resulting in cracking. The stereolithography curable composition of Reference Comparative Example 8 had a high light scattering index Sc, resulting in low modeling accuracy and cracking. The stereolithography curable composition of Reference Comparative Example 9 was prepared according to the method described in Patent Document 3, and had a low activation light transmittance, resulting in cracking.

[0146] II. Examples and Comparative Examples Examples and comparative examples of the curable composition for stereolithography of the present disclosure are shown below.

[0147] Example 1 (1) Preparation of base composition for Sc evaluation and photocurable composition To 100 parts by mass of a polymerizable monomer component (A) consisting of a monomer composition A7 (35 parts by mass of UDMA, 27 parts by mass of 3G, and 38 parts by mass of D-2.6E), 60 parts by mass of B-1 as a non-composite inorganic filler (B1) and 90 parts by mass of CF1 as an organic-inorganic composite filler (E) were added, and the mixture was stirred and mixed until uniform, followed by degassing to prepare a base composition for Sc evaluation.

[0148] Separately, a raw material base composition was prepared in the same manner, to which was added 1.4 parts by mass of a photopolymerization initiator consisting of BAPO, 0.7 parts by mass of an activated light absorber consisting of SS3, and a total of 0.2 parts by mass of a polymerization inhibitor consisting of 0.1 parts by mass of HQME and 0.1 parts by mass of BHT (all of these blending amounts are based on 100 parts by mass of the polymerizable monomer component), and the mixture was stirred and mixed under red light until uniform, followed by degassing to prepare a liquid curable composition for stereolithography.

[0149] (Measurement of light scattering index Sc and activation light transmittance) The light scattering index Sc and activation light transmittance of the obtained base composition for Sc evaluation and curable composition for stereolithography were measured in the same manner as in Reference Example 1. As a result, the light scattering index Sc was 0.5%, and the activation light transmittance was 6.9%.

[0150] (Evaluation of three-dimensional stereolithography and crack evaluation) Using the obtained curable composition for stereolithography, a three-dimensional stereolithography was produced in the same manner as in Reference Example 1, and the obtained three-dimensional stereolithography was evaluated. As a result, the average modeling accuracy was "1.01", and the crack evaluation result was "A1". An optical microscope photograph (magnification 50 times) taken during observation for crack evaluation is shown in Figure 6.

[0151] (Fluidity evaluation) 500 g of the stereolithography curable composition of Example 1 was supplied to a resin tray (tank) of a 3D printer (DWS, DW029D; wavelength: 405 nm, irradiation intensity: 83 mW), and a molding process was performed using stereolithography data (stl data) of a rectangular parallelepiped shape of 150 mm x 150 mm x 200 mm, and a molded body (laminate) having a laminated structure (composed of a cured product of the stereolithography curable composition) was produced. Next, the obtained molded body was immersed in a plastic container filled with ethanol for 15 minutes, gently shaken to perform a washing process, and then dried, and further subjected to additional light irradiation (secondary curing) using a UV CURING UNIT UVIS-2 (DWS) for 30 minutes to produce a three-dimensional stereolithography object.

[0152] The resulting rectangular 3D photofabricated object measuring 150 mm x 150 mm x 200 mm was observed visually and under an optical microscope (50x magnification) to evaluate whether there were any defects in the rectangular shape. As a result, it was confirmed that there were no defects both visually and under an optical microscope (50x magnification), and that the object had high fluidity (evaluation result: A).

[0153] Examples 2 to 20 and Comparative Examples 1 to 6 Base compositions for Sc evaluation and curable compositions for stereolithography were prepared in the same manner as in Example 1, except that the components and blending amounts used when preparing the base composition for Sc evaluation and the curable composition for stereolithography in Example 1 were changed as shown in Tables 8 and 9. Thereafter, each of the resulting compositions was evaluated in the same manner as in Example 1, and three-dimensional stereolithography objects were produced and evaluated using the resulting curable compositions for stereolithography in the same manner as in Example 1. The evaluation results are shown in Tables 10 and 11.

[0154]

[0155]

[0156]

[0157]

[0158] As shown in Table 10, the curable compositions for stereolithography of Examples 1 to 20 had a small light scattering index Sc and a high activation light transmittance, resulting in high modeling accuracy and suppressed cracking.

[0159] On the other hand, as shown in Table 11, the stereolithography curable composition of Comparative Example 1 had a large difference in refractive index at 405 nm between the composite inorganic filler (B2) constituting the organic-inorganic composite filler (E) and the resin (R), resulting in low transmittance for 405 nm light, and thus increased cracking. The stereolithography curable composition of Comparative Example 2 had a large difference in refractive index at 405 nm between the polymerizable monomer component (A) and the composite inorganic filler (B2) constituting the organic-inorganic composite filler (E), resulting in low transmittance for 405 nm light, and therefore increased cracking. The stereolithography curable composition of Comparative Example 3 had a large difference in refractive index at 405 nm between the polymerizable monomer component (A) and the resin (R) constituting the organic-inorganic composite filler (E), resulting in low transmittance for 405 nm light, and therefore increased cracking. The curable compositions for stereolithography of Comparative Examples 4 to 6 had a large difference in refractive index for 405 nm wavelength light between the polymerizable monomer component (A) and the composite inorganic filler (B2) and resin (R) constituting the organic-inorganic composite filler (E), and therefore had a low transmittance for 405 nm wavelength light, resulting in increased cracking.

[0160] Examples 21 to 32 and Comparative Examples 7 to 10 Three-dimensional stereolithography objects were manufactured and evaluated in the same manner as in Examples 1, 14, and 18 and Comparative Example 1, except that the 3D printer used to manufacture the three-dimensional stereolithography objects in Examples 1, 14, and 18 and Comparative Example 1 was changed as shown in Tables 12 and 13. The evaluation results are shown in Tables 12 and 13. Tables 12 and 13 also show the evaluation results for Examples 1, 14, and 18 and Comparative Example 1. The stereolithography curable composition used in Examples 21 to 24 has the same composition as the stereolithography curable composition used in Example 1. The stereolithography curable composition used in Examples 25 to 29 has the same composition as the stereolithography curable composition used in Example 14. The stereolithography curable composition used in Examples 29 to 32 has the same composition as the stereolithography curable composition used in Example 18. The stereolithography curable compositions used in Comparative Examples 7 to 10 had the same composition as the stereolithography curable composition used in Comparative Example 1.

[0161] The 3D printers 3DP1 to 3DP5 in Tables 12 and 13 refer to the following 3D printers: 3DP1: DW029D (SLA method, wavelength: 405 nm) manufactured by DWS; 3DP2: SEGA 3D (DLP method, wavelength: 405 nm) manufactured by 3BFAB; 3DP3: iLux Pro Dental (DLP method, wavelength: 385 nm) manufactured by Lux Creo; 3DP4: Smapri Sonic 8K (LCD method, wavelength: 405 nm) manufactured by Phrozen; 3DP5: SOL Plus (LCD method, wavelength: 385 to 405 nm) manufactured by Ackuretta.

[0162]

[0163]

[0164] As shown in Table 12, in Examples 21 to 32, which used the curable compositions for stereolithography prepared in Examples 1, 14, and 18, the crack evaluation results for the three-dimensional stereolithography objects were "A1" or "A0", regardless of the type of 3D printer. On the other hand, as shown in Table 13, in Comparative Examples 7 to 10, which used the curable composition for stereolithography prepared in Comparative Example 1, the crack evaluation results for the three-dimensional stereolithography objects were "B", regardless of the type of 3D printer.

Claims

1. In a liquid tank photopolymerization method for producing a three-dimensional object by irradiating a predetermined position of a liquid photocurable composition held in a tank with activating light containing light of a specific wavelength λ (nm) in the ultraviolet or visible light region to selectively cure the liquid photocurable composition present at that position, the liquid photocurable composition is a three-dimensional photocurable composition used as the liquid photocurable composition, the composition comprising: 100 parts by mass of a polymerizable monomer component (A); 40 to 400 parts by mass of an inorganic filler (B) composed of a single type or multiple types of inorganic powder and granules; 0.01 to 5 parts by mass of a photopolymerization initiator (C) that has the function of initiating photopolymerization upon irradiation with the activating light; and 0.01 to 2.5 parts by mass of an activating light absorber (D) that has the function of absorbing the activating light but does not have the ability to initiate photopolymerization; In the particle size distribution of the inorganic filler (B) measured by a microscopy method using a scanning microscope, 80% or more of all primary particles constituting the inorganic filler (B) are particles having a particle diameter of 0.05 to 5.0 μm; 10 to 90 mass% of the inorganic filler (B) is contained as an organic-inorganic composite filler (E) consisting of particles constituted by a composite material of the inorganic filler (B) and a resin (R); when the inorganic filler (B) that is not composited with the resin (R) is defined as a non-composite inorganic filler (B1) and the inorganic filler contained as the organic-inorganic composite filler (E) is defined as a composite inorganic filler (B2), 80% or more of all primary particles constituting each of the non-composite inorganic filler (B1) and the composite inorganic filler (B2) are particles having a particle diameter of 0.05 to 5.0 μm; the polymerizable monomer component (A), the non-composite inorganic filler (B1), and the organic-inorganic composite filler (E) are When a composition consisting of only the polymerizable monomer component (A), the non-composite inorganic filler (B1), and the organic-inorganic composite filler (E), in which the compositional ratio of these components is the same as that of the curable composition for three-dimensional optical fabrication, is used as a base composition, a measurement light beam containing the specific wavelength λ (nm), containing light within a range of λ±50 (nm) as a main component and exhibiting the maximum intensity within the range is measured using a goniophotometer, and based on the intensity of transmitted light in a specific emission angle direction, the following formula is calculated: Sc={(I ７０ +I ７５ +I ８０ ) / (I ０ ×3)}×100 (wherein, I ０ , I ７０ , I ７５ , and I ８０ indicates the intensity of transmitted light in each direction at an emission angle of 0°, 70°, 75°, and 80°, respectively.) The light scattering index: Sc (%) determined by the above formula (1) is 10(%) or less, and the transmittance of the activating light measured on a 0.5 mm thick sample made of the curable composition for three-dimensional optical fabrication is 1 to 50(%).

2. A method for producing a curable composition for three-dimensional optical shaping according to claim 1, comprising a mixing step of mixing the polymerizable monomer component (A), the non-composite inorganic filler (B1), the organic-inorganic composite filler (E), the photopolymerization initiator (C), and the activating light absorber (D), wherein the refractive index of the polymerizable monomer component (A) to the D line at 25°C and the refractive index to the activating light at 25°C are respectively n （Ｄ）Ｍ and n （ＡＬ）Ｍ The refractive index of the inorganic powder particles constituting the inorganic filler (B) with respect to the D line at 25° C. and the refractive index with respect to the activating light at 25° C. are respectively n （Ｄ）Ｆ and n （ＡＬ）Ｆ The refractive index of the resin (R) contained in the organic-inorganic composite filler (E) at 25°C with respect to the activating light is n （ＡＬ）Ｒ and when a composition consisting only of the polymerizable monomer component (A), the non-composite inorganic filler (B1), and the organic-inorganic composite filler (E), in which the compositional ratio of these components is the same as that of the curable composition for three-dimensional stereolithography that is the target of production, is used as a base composition, in the mixing step, the polymerizable monomer component (A), the non-composite inorganic filler (B1), and the organic-inorganic composite filler (E) must satisfy the following conditions 1 to 6: Condition 1: when the particle diameter of each primary particle constituting the inorganic filler (B) is x (nm) and pi is π, in the particle size distribution of the inorganic filler (B) measured by a microscopy method using a scanning microscope, the total number of particles having a particle diameter x (nm) in the range of 0.7λ / π to 4λ / π (nm) is 40% or more of the total number of primary particles constituting the inorganic filler (B); Condition 2: when the refractive index n （Ｄ）Ｆ When inorganic powder particles (b1) are inorganic powder particles consisting of an aggregate of a single type of inorganic particles having a refractive index in the range of 1.500 to 1.550, and inorganic powder particles (b2) are inorganic powder particles consisting of an aggregate of a single type of inorganic particles having a refractive index outside the above range, the non-composite inorganic filler (B1) and the composite inorganic filler (B2) are each: (1) composed of a single type of specific inorganic powder particle (b1), or (2) composed of a plurality of types of specific inorganic powder particle (b1), and at least one of the plurality of types of specific inorganic powder particle (b1) accounts for 10 mass% or more of the total mass of the non-composite inorganic filler (B1) and the composite inorganic filler (B2), respectively; or (3) A single or multiple specific inorganic powder or particles (b1): 90% by mass or more and less than 100% by mass, and a single or multiple non-specific inorganic powder or particles (b2): more than 0% by mass and 10% by mass or less, and at least one of the single or multiple specific inorganic powder or particles (b1) accounts for 10% by mass or more of the total mass of the non-composite inorganic filler (B1) and the composite inorganic filler (B2); Condition 3: The refractive index n （Ｄ）Ｍ is in the range of 1.490 to 1.550; Condition 4: The refractive index n of at least one specific inorganic powder or particle (b1) that accounts for 10% by mass or more of the total mass of the non-composite inorganic filler (B1) and the composite inorganic filler (B2) is in the range of 1.490 to 1.550; （Ｄ）Ｆ Among these, the refractive index n （Ｄ）Ｍ The refractive index where the difference between （Ｄ）Ｆｈ When （Ｄ）Ｆｈ and （Ｄ）Ｍ Absolute value of the difference with: |n （Ｄ）Ｆｈ -n （Ｄ）Ｍ Condition 5: the refractive index n of at least one specific inorganic powder or particle (b1) that accounts for 10% by mass or more of the total mass of the non-composite inorganic filler (B1) and the composite inorganic filler (B2) is 0.035 or less; （ＡＬ）Ｆ and the refractive index n （ＡＬ）Ｍ and the refractive index n （ＡＬ）Ｒ and the following formulas (i) to (iii): −0.015<(n （ＡＬ）Ｆ -n （ＡＬ）Ｍ )<0.025 (i) -0.015<(n （ＡＬ）Ｒ -n （ＡＬ）Ｍ )<0.030 (ii) -0.020<(n （ＡＬ）Ｆ -n （ＡＬ）Ｒ ) < 0.020 (iii) is satisfied; Condition 6: A sample of the base composition having a thickness of 0.5 mm is irradiated perpendicularly with measurement light containing light of the specific wavelength: λ (nm), containing light within a range of λ ± 50 (nm) as a main component, and exhibiting the maximum intensity within said range, using a goniophotometer, and based on the intensity of transmitted light in a specific emission angle direction, the following formula is satisfied: Sc = {(I ７０ +I ７５ +I ８０ ) / (I ０ ×3)}×100 (wherein, I ０ , I ７０ , I ７５ , and I ８０ indicates the intensity of transmitted light in each direction where the emission angle is 0°, 70°, 75°, and 80°, respectively.) The light scattering index: Sc (%) determined by 3. A method for manufacturing a three-dimensional optically modeled object by irradiating a predetermined position of a liquid photocurable composition held in a tank with activating light containing light of a specific wavelength λ (nm) in the ultraviolet or visible light region to selectively cure the liquid photocurable composition present at that position, the method comprising: a molding step of: digitizing and ranking the height direction of the three-dimensional object from three-dimensional shape data representing the shape of the three-dimensional object, and generating two-dimensional shape data representing the cross-sectional shape of the three-dimensional object at each ranked height; irradiating the liquid photocurable composition held in the tank with the activating light at a predetermined position determined based on the two-dimensional shape data, thereby selectively and primarily curing the liquid photocurable composition present at that position to form a modeling layer having the cross-sectional shape; and sequentially forming and stacking modeling layers having the cross-sectional shapes at each height in the order of the ranking to obtain a laminate having a shape corresponding to the shape of the three-dimensional object; a cleaning step of cleaning the laminate obtained in the molding step with an organic solvent; and a secondary curing step of subjecting the laminate cleaned in the cleaning step to additional irradiation with activating light, heat treatment, or both, thereby secondary curing, wherein the liquid photocurable composition is the curable composition for three-dimensional stereolithography according to claim 1.

4. A method for manufacturing a dental restoration, comprising manufacturing a dental restoration by the method for manufacturing a three-dimensional optically shaped object according to claim 3.

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