Curable composition for three-dimensional stereolithography, method for producing object by three-dimensional stereolithography, and method for producing dental restoration

Abstract

Provided is a curable composition for three-dimensional stereolithography, the curable composition containing 100 parts by mass of a radical polymerizable monomer (A), 5.0-400 parts by mass of an inorganic filler (B), 0.05-10.0 parts by mass of a photopolymerization initiator (C) containing an acylphosphine compound, 0.01-5.0 parts by mass of a polymerization inhibitor (D), and 0.01-10.0 parts by mass of a photosensitizer (E) including a thioxanthone compound represented by formula (1). The present invention also provides a method for producing an object by three-dimensional stereolithography and a method for producing a dental restoration, the methods using said curable composition for three-dimensional stereolithography. In the formula, Y1 to Y8 each independently represent a hydrogen atom, an alkyl group having 1-20 carbon atoms, or the like.

Description

CURABLE COMPOSITION FOR 3D PHOTOFORMING, METHOD FOR PRODUCING 3D PHOTOFORMED OBJECT, AND METHOD FOR PRODUCING DENTAL RESTORATION

[0001] The present disclosure relates to a curable composition for three-dimensional stereolithography, 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 stereolithography object by irradiating a photocurable composition (also called a "photocurable resin" or "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 stereolithography. 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 produced 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 the predetermined positions to form modeling layers 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 (also referred to as "post-polymerization") to obtain the target object. This secondary curing is generally performed to increase the polymerization rate and strength of the laminate by additionally irradiating the laminate with light and / or heat.

[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 corresponds to the condition of the oral cavity of each patient. For this reason, it has been considered to manufacture dental restorations by stereolithography using a liquid vat photopolymerization method based on CAD (Computer Aided Design) data designed using digital data obtained by intraoral scanning or the like (see, for example, Patent Document 1).

[0005] When manufacturing dental restorations for intraoral use, photocurable compositions containing a polymerizable monomer and a large amount of inorganic filler are sometimes used to increase strength. When such photocurable compositions containing a large amount of inorganic filler are used and sufficient secondary curing is performed to obtain high precision that allows the composition to fit the oral cavity of each individual patient, it is known that deformation due to polymerization shrinkage and the resulting stress generated between the modeling layers during stereolithography are likely to cause cracks (too small to be seen with the naked eye) inside and / or on the surface of the three-dimensional stereolithography object.

[0006] Therefore, techniques for preventing the occurrence of such problems have been studied. For example, Patent Document 2 discloses a method for producing a photocurable composition containing 100 parts by mass of a radically polymerizable monomer, 5.0 to 400 parts by mass of an inorganic filler, 0.05 to 10.0 parts by mass of a photopolymerization initiator that absorbs activating light to generate radicals, 0.01 to 2.7 parts by mass of an activating light absorber that absorbs activating light, and 0.01 to 5.0 parts by mass of a polymerization inhibitor, in which a molded body containing an effective amount of the photopolymerization initiator (a molded body consisting of a laminate of a primary cured product of the photocurable composition) is obtained by a liquid tank photopolymerization method in a molding step, and then a light intensity of 10 to 10,000 mW / cm is applied to the molded body in a post-polymerization step (secondary curing step). ２ and then heating the molded body at a temperature of 50°C or higher but lower than 110°C.

[0007] Patent Publication No. 2015-515327 International Publication No. 2023 / 008233

[0008] The technology described in Patent Document 2 is said to make it possible to manufacture a three-dimensional optically shaped object that has excellent mechanical strength, good shape accuracy, and is substantially free of internal cracks.

[0009] On the other hand, the technology described in Patent Document 2 requires the incorporation of an activated light absorber as an essential component in the photocurable composition, which can prevent cracks from occurring inside the 3D photo-printed object. However, depending on the specific heating conditions used in the post-polymerization process (secondary curing process), cracks may be observed on the surface of the 3D photo-printed object (see Example 11 of Patent Document 2). Furthermore, the inventors' studies have revealed that the greater the thickness of the molded body (laminate) obtained in the molding process, the greater the amount of cracks observed on the surface of the 3D photo-printed object. If the amount of cracks observed on the surface of the 3D photo-printed object is small, they have little effect on the mechanical strength of the entire 3D photo-printed object and can be removed by surface polishing, etc., so they are not usually a problem. However, if the amount of cracks increases, there is a concern that they may become problematic.

[0010] Therefore, the present disclosure aims to provide a curable resin composition for three-dimensional photo-polymerization that does not require the incorporation of an activated light absorber and that can prevent the occurrence of fine cracks not only inside but also on the surface of a three-dimensional photo-polymerized object, regardless of the specific heating conditions when performing a heat treatment at 50°C or higher but lower than 110°C in the post-polymerization step.

[0011] A first aspect of the present disclosure is a photopolymerizable composition comprising: 100 parts by mass of a radical polymerizable monomer (A); 5.0 to 400 parts by mass of an inorganic filler (B); 0.05 to 10.0 parts by mass of a photopolymerization initiator (C) containing an acylphosphine compound; 0.01 to 5.0 parts by mass of a polymerization inhibitor (D); and a photopolymerizable composition comprising: a compound represented by the following formula (1): (In the formula, Y １ ~Y ８ and each independently represent a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a halogen atom, an alkoxy group having 1 to 20 carbon atoms, an acyl group having 2 to 21 carbon atoms, or an alkylthio group having 1 to 20 carbon atoms.

[0012] The curable composition for three-dimensional optical fabrication according to the present disclosure preferably further contains 0.01 to 2.7 parts by mass of an activating light absorber (F) that absorbs activating light that activates the acylphosphine compound.

[0013] In addition, the curable composition for three-dimensional optical fabrication according to the present disclosure may further comprise a compound represented by the formula (1) above, wherein Y １ , Y ２ , and Y ４ are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a halogen atom, or an alkoxy group having 1 to 3 carbon atoms; Y ３ , Y ５ , Y ６ , Y ７ , and Y ８ is preferably a hydrogen atom.

[0014] Furthermore, in the curable composition for three-dimensional stereolithography of the present disclosure, it is preferable that the photopolymerization initiator (C) contains, as the acylphosphine compound, 0.05 to 5.0 parts by mass of at least one compound selected from the group consisting of diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, and ethoxyphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, and that the photosensitizer (E) consists of at least one compound selected from the group consisting of thioxanthone, 2-isopropylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, and 1-chloro-4-propyloxythioxanthone.

[0015] Further, a second aspect of the present disclosure includes a molding step of: digitizing and ranking the height direction of a three-dimensional object from three-dimensional shape data indicating the shape of the three-dimensional object, and generating two-dimensional shape data indicating the cross-sectional shape of the three-dimensional object at each ranked height; using a liquid tank photopolymerization method in which ultraviolet or visible light is irradiated to predetermined positions of a liquid photocurable composition held in a tank to selectively harden the liquid photocurable composition present at the positions; sequentially forming and stacking modeling layers having shapes corresponding to the two-dimensional shapes at each height in the order of the ranking based on the two-dimensional shape data, thereby obtaining a molded body made of a cured product of the liquid photocurable composition having a shape corresponding to the shape of the three-dimensional object; a washing step of washing the molded body obtained in the molding step with an organic solvent; and a post-polymerization step of polymerizing unpolymerized components contained in the molded body; wherein in the molding step, the molded body contains an effective amount of photopolymerization initiator, and the post-polymerization step is performed on the molded body at an irradiation light of 10 to 500 mW / cm. ２ and then heating the molded body that has been irradiated with the activating light at a temperature of 50°C or higher but lower than 110°C, wherein the liquid photocurable composition is a curable composition for three-dimensional stereolithography of the present disclosure.

[0016] In the method for producing a three-dimensional optically shaped object according to the present disclosure, the molded body irradiated with the activating light is preferably heated by irradiating the molded body with microwaves while the molded body is immersed in water.

[0017] A third 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.

[0018] According to the technology disclosed herein, when a three-dimensional photo-fabricated object is produced by a liquid tank photopolymerization method using a photo-curable composition containing a radical polymerizable monomer and a large amount of inorganic filler, which is capable of producing three-dimensional photo-fabricated objects that require high mechanical strength, such as dental restorations, even without adding an activating light absorber to the photo-curable composition, by performing a post-polymerization process including irradiation with activating light of a predetermined intensity followed by a heat treatment at 50°C or higher and lower than 110°C, it becomes possible to prevent the occurrence of fine cracks inside and on the surface of the three-dimensional photo-fabricated object (regardless of the specific conditions of the heat treatment).

[0019] 1 is a diagram showing an optical microscope image (magnification 5x) of the surface of a three-dimensional stereolithography object obtained in Example 1. FIG. 2 is a diagram showing an optical microscope image (magnification 5x) of the surface of a three-dimensional stereolithography object obtained in Example 2. FIG. 3 is a diagram showing an optical microscope image (magnification 5x) of the surface of a three-dimensional stereolithography object obtained in Comparative Example 1. FIG. 4 is a diagram showing an optical microscope image (magnification 5x) of the surface of a three-dimensional stereolithography object obtained in Comparative Example 4.

[0020] The technology disclosed herein solves the above-mentioned problems in the method for producing a three-dimensional optically shaped object described in Patent Document 2, and is characterized in that the photopolymerization initiator system in the photocurable composition used in the production method uses a combination of a photopolymerization initiator (C) containing an acylphosphine compound and a photosensitizer (E) consisting of a thioxanthone compound having a specific structure.

[0021] As described in Patent Document 2, acylphosphine compounds are photopolymerization initiators that are sometimes used in photocurable compositions used in liquid tank photopolymerization. As described in Patent Documents 1 and 2, thioxanthone compounds are sometimes used in combination with photopolymerization initiators as sensitizers or photosensitizing dyes, similar to many compounds such as benzoin, benzophenone, ketone compounds, coumarin dyes, cyanine dyes, merocyanine dyes, thiazine dyes, azine dyes, acridine dyes, xanthene dyes, squarium dyes, pyrylium salt dyes, and condensed polycyclic aromatic compounds (anthracene, perylene, etc.). However, to the inventors' knowledge, there have been no examples of the actual use of an acylphosphine compound and a thioxanthone compound of a specific structure in a photocurable composition for liquid tank photopolymerization containing an inorganic filler. Furthermore, the present inventors have confirmed for the first time that the combined use of an acylphosphine compound and a thioxanthone compound having a specific structure can provide the effect of preventing the occurrence of fine cracks inside and on the surface of a three-dimensional optically shaped object, even in the absence of an activated light absorber.

[0022] While the reason for this effect is unclear, the inventors speculate as follows: When an acylphosphine compound and a thioxanthone compound with a specific structure are used in combination, polymerization proceeds sufficiently even with weak activation light, suppressing the uneven polymerization (the occurrence of areas with low polymerization rates) that inevitably occurs during the formation of each modeling layer of the laminate, which is the primary cured product, due to attenuation of the activation light (which occurs when the activation light passes through the photocurable composition), thereby preventing the occurrence of fine cracks inside and on the surface of the three-dimensional photo-fabricated object. Both the acylphosphine compound and the thioxanthone compound with a specific structure absorb light with a wavelength around 400 nm. Because light in a wavelength range including this wavelength is typically used in the molding process and post-polymerization process, both the direct cleavage of the acylphosphine compound and the photosensitization effect of the thioxanthone compound with a specific structure effectively work in both processes.

[0023] The curable composition for three-dimensional stereolithography of the present disclosure is not particularly different from the photocurable composition used in the method for producing a three-dimensional stereolithography object described in Patent Document 2, except that it uses an acylphosphine compound in combination with a thioxanthone compound having a specific structure and does not require an activating light absorber. Furthermore, the method for producing a three-dimensional stereolithography object of the present disclosure is not particularly different from the method for producing a three-dimensional stereolithography object described in Patent Document 2, except that it uses the curable composition for three-dimensional stereolithography of the present disclosure. The curable composition for three-dimensional stereolithography of the present disclosure, including these features, will be described in detail below.

[0024] In this specification, unless otherwise specified, the expression "x to y" using numerical values ​​x and y means "greater than or equal to x and less than or equal to y." In such an expression, 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)acrylic" means both "acrylic" and "methacrylic." Similarly, the term "(meth)acrylate" means both "acrylate" and "methacrylate," and the term "(meth)acryloyl" means both "acryloyl" and "methacryloyl."

[0025] <Regarding the curable composition for three-dimensional stereolithography> [Radical polymerizable monomer (A)] As the radical polymerizable monomer (A), any radically polymerizable monomer can be used without any particular limitation. Among them, it is preferable to use a (meth)acrylate monomer because it has a fast curing rate and the resulting three-dimensional stereolithography product has excellent strength.

[0026] As the (meth)acrylate monomer, any of monofunctional (meth)acrylates, bifunctional (meth)acrylates, and trifunctional or higher functional (meth)acrylates may be used. However, from the viewpoint of being able to produce a three-dimensional photo-fabricated object with higher strength, it is preferable that 50 mass % or more, more preferably 80 mass % or more, and particularly 95 mass % or more of the (meth)acrylate monomer be bifunctional or higher functional polyfunctional (meth)acrylate, based on the total mass of all radically polymerizable monomers.

[0027] Suitable examples of the difunctional 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-based (meth)acrylates, such as triethylene glycol dimethacrylate and ethylene glycol dimethacrylate. 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 because of their low viscosity and excellent strength of the resulting three-dimensional stereolithography.

[0028] Furthermore, examples of monofunctional (meth)acrylates suitable for use in combination with difunctional or higher polyfunctional (meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, isopropyl (meth)acrylate, hydroxyethyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, and glycidyl (meth)acrylate.

[0029] As the radical polymerizable monomer (A), these (meth)acrylate monomers may be used alone or in combination.

[0030] [Inorganic Filler (B)] The curable composition for 3D stereolithography of the present disclosure contains 5.0 to 400 parts by mass of inorganic filler (B) per 100 parts by mass of radical polymerizable monomer (A) to enhance the mechanical strength, such as rigidity, of the resulting 3D stereolithography object. The higher the inorganic filler content, the higher the mechanical strength of the resulting 3D stereolithography object tends to be. For this reason, the content of inorganic filler (B) is preferably 10 parts by mass or more, more preferably 20 parts by mass or more, and even more preferably 100 parts by mass or more, per 100 parts by mass of radical polymerizable monomer (A). On the other hand, if the content of inorganic filler is too high, the viscosity of the curable composition for 3D stereolithography may increase, making stereolithography difficult. For this reason, the content of inorganic filler (B) is preferably 350 parts by mass or less, more preferably 300 parts by mass or less, and even more preferably 250 parts by mass or less, per 100 parts by mass of radical polymerizable monomer (A).

[0031] As the inorganic filler (B), an inorganic powder or granule composed of a single type or multiple types of inorganic particles is used. The material of the inorganic particles is not particularly limited, and examples thereof include those used as fillers in dental restorative materials. Specific examples include simple metals; metal oxides or metal composite oxides; metal salts such as metal fluorides, carbonates, sulfates, silicates, hydroxides, chlorides, sulfites, and phosphates; and composites of these metal salts. Preferably, metal oxides such as amorphous silica, quartz, alumina, titania, zirconia, barium oxide, yttrium oxide, lanthanum oxide, and ytterbium oxide are used; silica-based composite oxides such as silica-zirconia, silica-titania, silica-titania-barium oxide, and silica-titania-zirconia; glasses such as borosilicate glass, aluminosilicate glass, and fluoroaluminosilicate glass; metal fluorides such as barium fluoride, strontium fluoride, yttrium fluoride, lanthanum fluoride, and ytterbium fluoride; inorganic carbonates such as calcium carbonate, magnesium carbonate, strontium carbonate, and barium carbonate; and metal sulfates such as magnesium sulfate and barium sulfate. When producing dental restorations, it is preferable to use a powder or granule composed of particles of silica-zirconia, silica-titania, silica-titania-barium oxide, silica-titania-zirconia, etc., because of their strong X-ray contrast properties. From the viewpoint of the abrasion resistance of the cured product, it is most preferable to use a powder or granule composed of silica-zirconia particles.

[0032] It is desirable to treat the inorganic powder particles constituting the inorganic filler (B) with a surface treatment agent, such as a silane coupling agent, to improve compatibility with the radical polymerizable monomer (A) and to improve the mechanical strength and water resistance of the resulting three-dimensional stereolithography object. 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, methacryloxyoctyl-8-trimethoxysilane, γ-chloropropyl trimethoxysilane, γ-glycidoxypropyl methoxysilane, and hexamethyldisilazane.

[0033] The inorganic powder and granules constituting the inorganic filler (B) can be those generally known as dental restorative materials and having an average particle size of 0.01 to 100 μm (preferably 0.01 to 10 μm). Here, the average particle size can be confirmed by the particle size distribution of the inorganic filler (B) measured by microscopy using a scanning electron microscope. That is, the inorganic filler (B) used to prepare the curable composition for three-dimensional stereolithography of the present disclosure is photographed with 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 counted, and the primary particle diameter (maximum diameter): X of each particle is calculated. ｉ By measuring the particle size distribution of all primary particles, the particle size distribution can be determined. ｉ where i is a natural number from 1 to n and represents the number of each measured primary particle. The average (primary) particle diameter: X (nm) is the sum of the particle diameters of all measured primary particles (primary particles with i = 1 to n): ΣX ｉ Using the formula: X = ΣX ｉ / n.

[0034] From the viewpoint of suppressing an increase in viscosity of the curable composition for 3D stereolithography and suppressing sedimentation of inorganic powder particles, the inorganic filler (B) is preferably one in which, in the particle size distribution based on the number of inorganic fillers measured by microscopy using a scanning electron microscope, 80% or more of all primary particles have a particle diameter within the range of 0.05 to 5.0 μm, more preferably 0.08 to 2.0 μm, and even more preferably 0.1 to 1.0 μm. Furthermore, the number of particles within these particle diameter ranges is preferably 90% or more, more preferably 95% or more, of all primary particles. Note that, as long as they have such a particle size distribution overall, multiple inorganic powder particles with different particle size distributions and materials can also be mixed and used. While it is preferable to incorporate the inorganic powder particles as they are, some or all of them may be incorporated as powder particles composed of (organic-inorganic composite) particles formed by compounding with a resin.

[0035] [Photopolymerization initiator (C)] The curable composition for three-dimensional optical fabrication of the present disclosure contains 0.05 to 10.0 parts by mass, preferably 0.2 to 8.0 parts by mass, and more preferably 0.3 to 5.0 parts by mass of the photopolymerization initiator (C) per 100 parts by mass of the radical polymerizable monomer (A).

[0036] Furthermore, in order to obtain the effects of the present invention, the photopolymerization initiator (C) must contain an acylphosphine compound. The acylphosphine compound is not particularly limited as long as it functions as a photopolymerization initiator, but diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, and ethoxyphenyl(2,4,6-trimethylbenzoyl)phosphine oxide are preferred because they are easily available.

[0037] From the viewpoint of effectiveness, the content of the acylphosphine compound is preferably 0.05 to 5.0 parts by mass, more preferably 0.3 to 4.0 parts by mass, and even more preferably 0.5 to 3.0 parts by mass, relative to 100 parts by mass of the radical polymerizable monomer (A).

[0038] The photopolymerization initiator (C) may contain a photopolymerization initiator other than the acylphosphine compound. As the other photopolymerization initiator, a photopolymerization initiator that absorbs the activating light irradiated in the post-polymerization step is preferably used. Examples of the other photopolymerization initiator include benzoketal compounds, benzyne compounds, α-aminoacetophenone compounds, α-hydroxyacetophenone compounds, titanocene compounds, and acyloxime compounds.

[0039] The photopolymerization initiator (C) can also be used in combination with a photoacid generator. Examples of the photoacid generator include iodonium salt compounds such as p-isopropylphenyl-p-methylphenyliodonium tetrakispentafluorophenylborate salt, sulfonium salt compounds such as dimethylphenacylsulfonium hexafluoroantimonate salt, and halomethyl group-substituted triazine compounds such as 2,4,6-tris(trichloromethyl)-s-triazine.

[0040] [Polymerization inhibitor (D)] The curable composition for 3D optical printing of the present disclosure contains 0.01 to 5.0 parts by mass of a polymerization inhibitor (D) relative to 100 parts by mass of the radical polymerizable monomer (A) in order to improve its storage stability and modeling accuracy. The content of the polymerization inhibitor (D) is preferably 0.03 to 4.0 parts by mass, more preferably 0.05 to 2.5 parts by mass, relative to 100 parts by mass of the radical polymerizable monomer (A).

[0041] As the polymerization inhibitor, a compound that reacts with radicals generated in the curable composition for three-dimensional stereolithography to deactivate the radicals can be used, and for example, di-tert-butyl-p-cresol, 4-methoxyphenol, etc. are preferably used.

[0042] [Photosensitizer (E)] In order to prevent cracking on the surface of a molded product during the post-polymerization step (secondary curing), the curable composition for three-dimensional stereolithography of the present disclosure must contain 0.01 to 10.0 parts by mass of a photosensitizer (E) composed of a thioxanthone compound represented by the following formula (1) relative to 100 parts by mass of the radical polymerizable monomer (A). When the content of the photosensitizer (E) is 0.01 parts by mass or more, a sufficient effect of preventing cracking on the surface tends to be obtained, while when the content is 10.0 parts by mass or less, the molding accuracy of the molded product tends to be improved. The content of the photosensitizer (E) is preferably 0.05 to 5.0 parts by mass, more preferably 0.1 to 4.0 parts by mass, and even more preferably 0.2 to 3.0 parts by mass relative to 100 parts by mass of the radical polymerizable monomer (A).

[0043]

[0044] Y in the above formula (1) １ ~Y ８ each independently represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a halogen atom, an alkoxy group having 1 to 20 carbon atoms, an acyl group having 2 to 21 carbon atoms, or an alkylthio group having 1 to 20 carbon atoms.

[0045] Examples of alkyl groups having 1 to 20 carbon atoms include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, and n-hexyl. The number of carbon atoms in the alkyl group is preferably 1 to 10, more preferably 1 to 6, and even more preferably 1 to 4. Examples of halogen atoms include fluorine, chlorine, bromine, and iodine. Examples of alkoxy groups having 1 to 20 carbon atoms include those having the above-mentioned alkyl groups having 1 to 20 carbon atoms as the alkyl moiety. Examples of acyl groups having 2 to 21 carbon atoms include alkylcarbonyl groups having the above-mentioned alkyl groups having 1 to 20 carbon atoms as the alkyl moiety; and arylcarbonyl groups such as benzoyl. Examples of alkylthio groups having 1 to 20 carbon atoms include those having the above-mentioned alkyl groups having 1 to 20 carbon atoms as the alkyl moiety.

[0046] Among the thioxanthone compounds represented by the above formula (1), Y １ , Y ２ , and Y ４ are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a halogen atom, or an alkoxy group having 1 to 3 carbon atoms; Y ３ , Y ５ , Y ６ , Y ７ , and Y ８ is preferably a hydrogen atom.

[0047] Specific examples of the thioxanthone compound represented by the formula (1) above include thioxanthone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-n-propylthioxanthone, 2-isopropylthioxanthone, 4-isopropylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone, 1-chloro-4-propyloxythioxanthone, etc. Among these, thioxanthone, 2-isopropylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, and 1-chloro-4-propyloxythioxanthone are preferred.

[0048] [Activating Light Absorber (F)] The curable composition for three-dimensional stereolithography of the present disclosure preferably contains 0.01 to 2.7 parts by mass of an activating light absorber (F) that has the function of absorbing the activating light that activates the acylphosphine compound, i.e., the activating light irradiated from the stereolithography device in the molding process, but does not function as a polymerization initiator, in order to prevent excessive transmission of the activating light irradiated from the stereolithography device, which would result in a decrease in modeling accuracy. The content of the activating light absorber (F) is more preferably 0.08 to 2.0 parts by mass, and even more preferably 0.25 to 1.0 part by mass, per 100 parts by mass of the radical polymerizable monomer (A).

[0049] The activating light absorber (F) is not particularly limited as long as it is a compound that absorbs activating light emitted 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.

[0050] [Other Components] The curable composition for three-dimensional stereolithography of the present disclosure may contain a chain transfer agent, a thermal polymerization initiator, a coloring substance, and the like, as needed.

[0051] 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, α-alkylstyrene compounds, and particularly α-methylstyrene dimer, are preferred because of their high crack suppression effect.

[0052] When the curable composition for three-dimensional stereolithography of the present disclosure contains a chain transfer agent, the content thereof is usually 0.00001 to 1.0 part by mass per 100 parts by mass of the radical polymerizable monomer (A).

[0053] The thermal polymerization initiator functions as a polymerization initiator for secondary curing in a subsequent step. As the thermal polymerization initiator, a thermal polymerization initiator having a 10-hour half-life temperature of 50 to 130°C is preferred, since it does not function during primary curing in the molding step and 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.

[0054] When the curable composition for three-dimensional optical fabrication according to the present disclosure contains a thermal polymerization initiator, the content thereof 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, relative to 100 parts by mass of the radical polymerizable monomer (A).

[0055] Coloring substances are blended to reproduce the color of tooth crowns and oral mucosa when producing dental restorations such as inlays, onlays, crowns, and dentures. 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.

[0056] <Regarding the manufacturing method of a three-dimensional optically shaped object> The manufacturing method of a three-dimensional optically shaped object of the present disclosure is a method for manufacturing a three-dimensional optically shaped object by a liquid vat photopolymerization method including a molding step, a cleaning step, and a post-polymerization step, as described in Patent Document 2, in which the curable composition for three-dimensional optical shaping of the present disclosure is used as the liquid photocurable composition supplied into the tank of a liquid vat photopolymerization device.

[0057] In the method for producing a three-dimensional optically shaped object described in Patent Document 2, a photocurable composition containing an activated light absorber as an essential component is primarily cured in the molding step to obtain a molded object containing an effective amount of a photopolymerization initiator, and a post-polymerization step performed after the washing step is performed by applying a 10 to 10,000 mW / cm to the molded object. ２The generation of fine cracks inside the three-dimensional optically shaped object is prevented by irradiating the molded object with activating light having an irradiation intensity of 100°C or more and heating the molded object irradiated with the activating light at a temperature of 50°C or more and less than 110°C. In this manufacturing method, in order to efficiently obtain a high-strength three-dimensional optically shaped object without internal cracks, it is considered important to control the heating temperature in the post-polymerization step, and it is preferable to sequentially perform temperature condition 1, temperature condition 2, and temperature condition 3 shown below, with the total heating time being preferably 5 minutes or more. Temperature condition 1: 50°C or more and less than 75°C Temperature condition 2: 75°C or more and less than 90°C Temperature condition 3: 90°C or more and less than 110°C

[0058] In contrast, in the method for producing a three-dimensional optically shaped object of the present disclosure, by using the curable composition for three-dimensional optically shaped object of the present disclosure, it is possible to prevent cracks from occurring on the surface as well as inside the three-dimensional optically shaped object, without requiring an activated light absorber as an essential component, and without strictly controlling the heating temperature in the heating performed after light irradiation in the post-polymerization step.

[0059] Each step in the method for producing a three-dimensional optically shaped object of the present disclosure is the same as each step in the method for producing a three-dimensional optically shaped object described in Patent Document 2, except that the curable composition for three-dimensional optical shaping of the present disclosure is used as the liquid photocurable composition supplied into the tank of the liquid tank photopolymerization device, the irradiation intensity of the activating light in the post-polymerization step is limited, and it is not necessary to strictly control the heating temperature in the post-polymerization step. Each step will be described below.

[0060] The method for producing a three-dimensional optically shaped object of the present disclosure includes a molding step, which includes: a first step of irradiating a liquid photocurable composition held in a tank with activating light at a predetermined position based on two-dimensional shape data at a height of an initial ranking order, thereby curing the composition, to form 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 liquid photocurable composition supplied immediately above or below the bonded layer with activating light at a predetermined position based on two-dimensional shape data at a height next in the ranking order in the previous step, thereby curing the liquid photocurable composition, to form a new modeling layer having a shape corresponding to the two-dimensional shape data, and bonding the new modeling layer to the bonded layer, to obtain a laminate; 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. Preferably, the cycle consisting of the third and fourth steps is repeated using the new bonded layer as the bonded layer in the third step, and in the final third step, a new modeling layer is formed based on the two-dimensional shape data corresponding to the final ranking order to obtain a laminate. This laminate corresponds to a molded body (composed of a cured product of the liquid photocurable resin composition having a shape corresponding to the shape of the three-dimensional object).

[0061] Such a liquid tank photopolymerization method including a molding step can be suitably carried out using a commercially available liquid tank photopolymerization device known as a 3D printer. The wavelength (peak wavelength) of the activating light in the molding step is preferably 380 to 420 nm. Note that general-purpose liquid tank photopolymerization devices often use a light source with an activating light wavelength of 405 nm or 385 nm.

[0062] In the method for producing a three-dimensional optically shaped object of the present disclosure, it is important that unreacted photopolymerization initiator remains in the laminate (molded body) immediately after the molding step, and that no photopolymerization initiator remains in the three-dimensional optically shaped object after the post-polymerization step.

[0063] The presence or absence of remaining photopolymerization initiator can be confirmed by any method. For example, when a photopolymerization initiator that absorbs in the visible light region, such as phenylbis(2,4,6-trimethylbenzoyl)-phosphine oxide, is used, the remaining phenylbis(2,4,6-trimethylbenzoyl)-phosphine oxide in the molded product immediately after the molding step is confirmed to be yellow, and the color fades after the post-polymerization step. Alternatively, the presence or absence of remaining photopolymerization initiator can be confirmed by crushing a portion of the obtained three-dimensional stereolithographic object, extracting it with any organic solvent, and analyzing it by a known analytical method (e.g., high-performance liquid chromatography, gas chromatography, etc.).

[0064] In the method for producing a three-dimensional optically shaped object of the present disclosure, in the cleaning step, the laminate (molded body) obtained in the molding step is washed with an organic solvent, and then in the post-polymerization step, additional activating light irradiation is performed, followed by heat treatment to cause secondary curing.

[0065] 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 in terms of their high washing effect, and alcohol-based solvents are more preferred in terms of their low environmental impact.

[0066] The wavelength of the additional activating light irradiation in the post-polymerization 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 wavelength (peak wavelength) of the activating light in the post-polymerization step is, for example, 350 to 500 nm. The irradiation intensity of the additional activating light irradiation is 10 to 500 mW / cm. ２ The lower limit of the irradiation intensity is, for example, 30 mW / cm ２The upper limit of the irradiation intensity is, for example, 300 mW / cm ２ Preferably, it is 100 mW / cm or less. ２ 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.

[0067] The temperature to which the molded body irradiated with activating light is heated may be 50°C or higher and lower than 110°C, preferably 50 to 90°C, and more preferably 55 to 80°C.

[0068] The heating treatment in the post-polymerization step can also be carried out by microwave irradiation. The microwave irradiation device used for heating by microwave irradiation preferably has an output of 300 W or more, and from the viewpoints of availability and ease of handling, it is preferable to use a microwave oven that is commonly used for general households. The heating time may be adjusted appropriately depending on the irradiation intensity and the amount of sample, but is usually from 1 minute to less than 15 minutes, preferably from 3 minutes to less than 10 minutes.

[0069] When heating by microwave irradiation, it is preferable to irradiate the three-dimensional optically shaped object while it is immersed in water, rather than irradiating the three-dimensional optically shaped object directly, since this can further suppress cracking.

[0070] <Regarding the Manufacturing Method for Dental Restorations> The manufacturing method for dental restorations of the present disclosure is a method for manufacturing a three-dimensional stereolithography object of the present disclosure, which manufactures dental restorations such as inlays, onlays, crowns, and dentures. When manufacturing such dental restorations, it is preferable to blend an activating light absorber (F) into the curable composition for three-dimensional stereolithography of the present disclosure. The three-dimensional shape data representing the shape of the dental restoration (three-dimensional object) used in the molding process may be CAD data designed based on digital data obtained by scanning the intraoral shape of an individual patient or an intraoral model created for each patient. The manufacturing method for dental restorations of the present disclosure allows the manufacture of dental restorations that have high mechanical strength and are free of cracks inside and on the surface.

[0071] The present invention will be explained in more detail below with reference to examples, but the present invention is not limited to these examples.

[0072] The compounds and their abbreviations used in the examples and comparative examples are as follows:

[0073] (1) Radically Polymerizable Monomer (A) Monomer compositions A1 and A2 were used, which were prepared by mixing the following monomer compounds as shown below. (Monomer Compounds) UDMA: urethane dimethacrylate 3G: triethylene glycol dimethacrylate D-2.6E: bisphenol A ethylene glycol (EO) adduct dimethacrylate (average number of EOs added: 2.6) (Monomer Compositions) A1: a mixture of 25 parts by mass of UDMA, 25 parts by mass of 3G, and 50 parts by mass of D-2.6E A2: a mixture of 50 parts by mass of UDMA, 20 parts by mass of 3G, and 30 parts by mass of D-2.6E

[0074] (2) Inorganic Filler (B) A mixture of the following inorganic powders was used: D-1: spherical silica-zirconia having an average particle size of 280 nm (surface treated with γ-methacryloyloxypropyltrimethoxysilane) D-2: a mixture of 70 parts by mass of spherical silica-zirconia having an average particle size of 500 nm (surface treated with γ-methacryloyloxypropyltrimethoxysilane) and 30 parts by mass of spherical silica-zirconia having an average particle size of 80 nm (surface treated with γ-methacryloyloxypropyltrimethoxysilane).

[0075] (3) Photopolymerization initiator (C) (acylphosphine compounds) BAPO: phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide TPO: 2,4,6-trimethylbenzoyl-diphenylphosphine oxide TPO-L: ethoxyphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (Compounds other than acylphosphine compounds) CQ: camphorquinone DMBE: dimethyl p-ethoxybenzoate IRGAGURE1173: 2-hydroxy-2-methyl-1-phenylpropane

[0076] (4) Polymerization inhibitor (D) BHT: dibutylhydroxytoluene HQME: hydroquinone methyl ether

[0077] (5) Photosensitizer (E) (Thioxanthone compounds represented by the above formula (1)) IPTO: 2-isopropylthioxanthone DETO: 2,4-diethylthioxanthone CPTO: 1-chloro-4-propyloxythioxanthone (Other compounds) DBuOA: 9,10-dibutoxyanthracene Coumarin 30: 3-(2-N-methylbenzimidazolyl)-7-N,N-diethylaminocoumarin

[0078] (6) Activated Light Absorber (F) SS701: 2-(2-hydroxy-5-methylphenyl)-2H-benzotriazole SS703: 2-(3-tert-butyl-2-hydroxy-5-methylphenyl)-5-chloro-2H-benzotriazole

[0079] Example 1 To 100 parts by mass of the monomer composition A1 (as the radical polymerizable monomer (A)), the components shown in Example 1 in Table 1 were added in the amounts shown in Table 1. The mixture was stirred and degassed under red light until homogeneous, thereby preparing a liquid photocurable composition. The resulting liquid photocurable composition was then used to produce multiple molded articles (composed of a cured product of the liquid photocurable resin composition) of predetermined shapes (a square with top and bottom surfaces measuring 2.05 mm x 2.05 mm, a height of 25.05 mm, and four side surfaces measuring 2.05 mm x 25.05 mm) using a 3D printer (DWS, DW029D; peak wavelength of activation light: 405 nm), and these were washed with ethanol. A portion of the resulting molded articles was used as a test piece before the post-polymerization step. The remaining molded articles were then subjected to polymerization in a dental laboratory polymerization apparatus (Tokuyama Dental Corporation, Portalite; peak wavelength of activation light: 470 nm, irradiation intensity: 53 mW / cm). ２ After that, the resultant was subjected to heat treatment in an incubator at 90° C. for 30 minutes to prepare a plurality of test pieces after the post-polymerization step.

[0080] The obtained test pieces were used to measure bending strength and evaluate cracking as described below.

[0081] (1) Bending Strength Measurement The above test specimens were polished with #800 waterproof abrasive paper to form rectangular columns with a 2 mm × 2 mm square base and a height of 25 mm. After observing under a microscope to confirm that no cracks remained on the surface of the rectangular column-shaped test specimen, the rectangular column-shaped test specimen was mounted on a testing machine (Shimadzu Corporation, Autograph AG5000D) as a bending test specimen, and the three-point bending fracture strength was measured at a support distance of 20 mm and a crosshead speed of 1 mm / min. The evaluation results are shown in Table 3.

[0082] (2) Crack Evaluation: An arbitrary side of a rectangular parallelepiped test piece with an unpolished surface was selected, and the surface containing the center of the side, approximately 2.0 mm x approximately 2.0 mm, and parallel to each side of the opposing side of the test piece, was used as the observation surface. The number of cracks present on the observation surface was then counted using an optical microscope (5x magnification), and this was used to evaluate cracks on the "surface of the test piece." Furthermore, the observation surface was polished vertically by approximately 100 to 200 μm, and the polished surface was observed under a microscope to evaluate cracks on the "interior of the test piece." Crack evaluation was performed according to the following evaluation criteria. Observation and crack evaluation were performed twice: before the post-polymerization process (after washing with ethanol) and after the post-polymerization process (after heat treatment). As a result, the evaluation was "A0" before the post-polymerization process and "A1" after the post-polymerization process. - Evaluation Criteria - A0: No cracks were observed inside the test piece, and no cracks were observed on the surface of the test piece. A1: No cracks are observed inside the test piece, and a small number of fine cracks (up to 5) are observed on the surface of the test piece, but this is within the acceptable range. A2: No cracks are observed inside the test piece, and a large number of fine cracks (6 or more) are observed on the surface of the test piece, but this is within the acceptable range. B: Clear cracks are observed on the surface of the test piece, and this is outside the acceptable range. C: A large number of clear cracks are observed on the surface of the test piece, and this is outside the acceptable range.

[0083] Examples 2 to 15 and Comparative Examples 1 to 7 Preparation of liquid photocurable compositions, production of molded articles and test specimens, and evaluation of the test specimens were carried out in the same manner as in Example 1, except that the formulations of the liquid photocurable compositions were changed as shown in Tables 1 and 2. The results are shown in Table 3.

[0084] Examples 16 to 24 and Comparative Example 8 Liquid photocurable compositions were prepared and molded bodies were produced in the same manner as in Example 1, except that the composition of the liquid photocurable composition was changed as shown in Tables 1 and 2. The resulting molded bodies were washed with ethanol and then irradiated with light for 10 minutes in the same manner as in Example 1. Next, a portion of the molded bodies after light irradiation was heat-treated in an incubator at 80°C for 30 minutes (heat treatment 1) to prepare test specimens, which were then evaluated in the same manner as in Example 1. Furthermore, for Examples 16, 18 to 20, 23, and 24, test specimens were prepared by changing the heat treatment conditions to the following heat treatments 2 and 3, and the same evaluations as in Example 1 were performed. That is, a portion of the molded bodies after light irradiation was placed in a heat-resistant container and heat-treated in a microwave oven (Twinbird Corporation, DR-F2828) at 500W for 3 minutes (heat treatment 2) to prepare test specimens. The remaining molded body was immersed in 100 mL of pure water in a 300 mL beaker and heated in a microwave oven at 500 W for 6 minutes (heat treatment 3) to prepare a test piece. The results are shown in Table 4.

[0085] The viscosity at 25° C. of the liquid photocurable compositions of Examples 1 to 24 and Comparative Examples 1 to 8 was in the range of 40,000 to 50,000 mPa·s.

[0086]

[0087]

[0088]

[0089]

[0090] As shown in Tables 3 and 4, the liquid photocurable compositions of Examples 1 to 24 used both an acylphosphine compound as a photopolymerization initiator and a thioxanthone compound as a photosensitizer, and therefore no or very few cracks occurred on the surface of the 3D stereolithography object even after the post-polymerization step. Furthermore, as shown in the results of Examples 16, 18 to 20, 23, and 24 in Table 4, when Heat Treatment 3, which involved heating in water using a microwave oven, was used as the heat treatment method, cracks on the surface of the 3D stereolithography object were further reduced compared to when Heat Treatments 1 and 2 were used in an air atmosphere.

[0091] On the other hand, the liquid photocurable composition of Comparative Example 1 did not use an acylphosphine compound as a photopolymerization initiator, and cracking increased after the post-polymerization step. The liquid photocurable compositions of Comparative Examples 2 to 5 and 8 did not use a thioxanthone compound as a photosensitizer, and cracking increased after the post-polymerization step. The liquid photocurable compositions of Comparative Examples 6 and 7 used a compound other than a thioxanthone compound as a photosensitizer, and cracking increased after the post-polymerization step.

Claims

1. Radical polymerizable monomer (A): 100 parts by mass, inorganic filler (B): 5.0 to 400 parts by mass, photopolymerization initiator (C) containing an acylphosphine compound: 0.05 to 10.0 parts by mass, polymerization inhibitor (D): 0.01 to 5.0 parts by mass, and a compound represented by the following formula (1): (In the formula, Y １ ~Y ８ and each independently represent a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a halogen atom, an alkoxy group having 1 to 20 carbon atoms, an acyl group having 2 to 21 carbon atoms, or an alkylthio group having 1 to 20 carbon atoms.

2. The curable composition for three-dimensional optical fabrication according to claim 1, further comprising 0.01 to 2.7 parts by mass of an activating light absorber (F) that absorbs activating light that activates the acylphosphine compound.

3. Y in the formula (1) １ , Y ２ , and Y ４ are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a halogen atom, or an alkoxy group having 1 to 3 carbon atoms; Y ３ , Y ５ , Y ６ , Y ７ , and Y ８ The curable composition for three-dimensional optical shaping according to claim 1 , wherein is a hydrogen atom.

4. The curable composition for three-dimensional stereolithography according to claim 1, wherein the photopolymerization initiator (C) contains, as the acylphosphine compound, 0.05 to 5.0 parts by mass of at least one compound selected from the group consisting of diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, and ethoxyphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, and the photosensitizer (E) comprises at least one compound selected from the group consisting of thioxanthone, 2-isopropylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, and 1-chloro-4-propyloxythioxanthone.

5. A molding process comprising: a step 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, and using a liquid tank photopolymerization method in which ultraviolet or visible light is irradiated to a predetermined position of a liquid photocurable composition held in a tank to selectively harden the liquid photocurable composition present at that position, to sequentially form and stack modeling layers having shapes corresponding to the two-dimensional shapes at each height in the order of the ranking based on the two-dimensional shape data, thereby obtaining a molded body made of a cured product of the liquid photocurable composition having a shape corresponding to the shape of the three-dimensional object; a washing step of washing the molded body obtained in the molding step with an organic solvent; and a post-polymerization step of polymerizing unpolymerized components contained in the molded body; wherein in the molding step, a molded body containing an effective amount of photopolymerization initiator is obtained, and the post-polymerization step is performed on the molded body at an irradiation light of 10 to 500 mW / cm. ２ and then heating the molded body irradiated with the activating light at a temperature of 50°C or higher but lower than 110°C, wherein the liquid photocurable composition is the curable composition for three-dimensional stereolithography according to claim 1.

6. The method for producing a three-dimensional optically shaped object according to claim 5, wherein the molding irradiated with the activating light is heated by irradiating the molding with microwaves while the molding is immersed in water.

7. 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 5.

Images