Curable composition for three-dimensional stereolithography and method for producing dental member

Abstract

In this invention, fluidity suitable for producing a dental member by vat photopolymerization is provided, and adhesion between the dental member and a liner material or another member corresponding to the liner material is excellent even after the dental member is used in an oral cavity for a long period of time. This curable composition for three-dimensional stereolithography comprises: (A) 100 parts by mass of a (meth)acrylate-based polymerizable monomer component that contains a polyfunctional (meth)acrylate-based polymerizable monomer and contains no methyl (meth)acrylate; (B) 0.7-220 parts by mass of a monofunctional (meth)acrylate polymer that has a number average molecular weight of 1,000-50,000 as measured by gel permeation chromatography; and (C) a photopolymerization initiator.

Description

CURABLE COMPOSITION FOR 3D PHOTO-PRODUCTION AND METHOD FOR PRODUCING DENTAL PARTS

[0001] The present invention relates to a curable composition for three-dimensional stereolithography and a method for producing a dental part.

[0002] Resin denture bases, which are components of dentures (a type of dental prosthesis), are typically prepared by pouring a curable resin composition into a plaster mold that conforms to the shape of the patient's oral cavity and allowing it to harden. This preparation method typically uses a mixture (curable resin composition) prepared by mixing a liquid material primarily composed of a (meth)acrylate monomer with a powder material primarily composed of a (meth)acrylate non-crosslinked polymer with a weight-average molecular weight of approximately 470,000 to 930,000 (see Patent Document 1 and Non-Patent Document 1). The primary purpose of mixing the powder material with the liquid material is to prevent a decrease in the adaptability (of the prepared denture base to the patient's oral cavity) due to polymerization shrinkage of the liquid material. From the perspective of operability and transfer accuracy, the mixture is poured into the mold and cured in a state where the viscosity of the mixture does not increase too much (maintaining a liquid or loose paste state) due to excessive swelling of the non-crosslinked polymer in the powder material caused by the monomer in the liquid material.

[0003] The denture base prepared by the above-mentioned method, due to the use of the curable resin composition containing a powder material, can be well bonded to a lining material by using an adhesive composition containing an organic solvent such as ethyl acetate, a monomer, and a non-crosslinked polymer, as described in Patent Document 2. Here, the lining material is a material used in a lining (also called a base lining: rebasing) operation to improve the deterioration of the fit between a patient's oral mucosa, which has gradually progressed during denture wearing due to bone resorption or deformation of the mucosal surface, and a denture (and its denture base) that has been used for a long time. Similar to the curable resin composition for denture base preparation, the lining material is generally composed of a liquid material primarily composed of a (meth)acrylate monomer and a powder material primarily composed of a non-crosslinked polymer, and the liquid material and powder material are mixed together when used.

[0004] Recently, as a method for efficiently producing denture bases while reducing the number of visits by patients to the clinic, a method has been proposed in which, instead of the above-mentioned method using a plaster mold, a denture base is produced by a stereolithography method based on data obtained by measuring the shape of the patient's oral cavity using three-dimensional measurement (for example, Patent Document 3).

[0005] While several stereolithography methods are known, the liquid vat photopolymerization method is widely used, as it can produce smooth-surfaced objects with high precision using a relatively inexpensive 3D printer. In the liquid vat photopolymerization method, the target object is manufactured by sequentially performing the following steps (i) to (iii) or (i) to (iv): (i) First, the height direction of the three-dimensional object to be manufactured is digitized and ranked based on three-dimensional shape data representing the shape of the three-dimensional object. Two-dimensional shape data representing the cross-sectional shape of the three-dimensional object at each ranked height is then generated. (ii) Next, activation light is applied to predetermined positions (positions determined based on the two-dimensional shape data) in the liquid photocurable composition held in the vat, selectively curing a portion of the photocurable composition in the vat. This results in the formation of a modeling layer having a cross-sectional shape corresponding to the two-dimensional shape data at each ranked height. Note that "liquid" here refers to the state of the photocurable composition in a liquid or dispersion containing inorganic powders and particles dispersed in the photocurable composition in the environment in which it is used. (iii) Step (ii) is repeated in the order in which the height direction of the three-dimensional object is digitized and ranked, thereby forming and stacking modeling layers in the height direction. This results in a laminate corresponding to the shape of the three-dimensional object. (iv) After step (iii) is completed, if necessary, the resulting laminate is washed with an organic solvent and then subjected to a secondary curing. Note that the secondary curing generally involves a second light irradiation and / or heat treatment of the laminate. The secondary curing is performed to improve the polymerization rate and the strength of the laminate.

[0006] Representative stereolithography methods using 3D printers include the SLA (stereolithography) method, LCD (liquid crystal display) method, DLP (digital light processor) method, etc. In all of these stereolithography methods, a photocurable composition stored in a liquid vat is irradiated with position-selective light rays to cure it, thereby forming a three-dimensional object.

[0007] The curable resin composition obtained by mixing the above-mentioned powder material and liquid material has a high viscosity and therefore cannot be used in the liquid vat photopolymerization method (see paragraph 0013 of Patent Document 4). In contrast, the compositions described in Patent Documents 4 and 5, for example, have been proposed as specific compositions for use in producing dental prostheses such as denture bases by stereolithography.

[0008] Patent Document 4 discloses a photocurable viscous mixture containing, relative to the total weight of the composition, 0-50 wt% of a solution of polymerized poly(methyl methacrylate) dissolved in a methyl methacrylate monomer solvent, 5-20 wt% of at least one polyfunctional aliphatic (meth)acrylate, 5-40 wt% of at least one aliphatic urethane (meth)acrylate oligomer, 25-65 wt% of at least one difunctional bisphenol-A dimethacrylate, 0.1-5 wt% of at least one photoinitiator, 0.05-2 wt% of at least one light stabilizer, and 0.1-3 wt% of a color pigment. The composition described in Patent Document 4 has a viscosity and curing speed suitable for three-dimensional printing, thereby achieving the desired mechanical properties for denture bases and artificial teeth.

[0009] Furthermore, Patent Document 5 discloses a composition for producing a three-dimensional dental prosthesis, comprising a mixture of 1-99.5% monomer, 5-99% at least one monofunctional or polyfunctional (meth)acrylate, 0-60% at least one inorganic filler, 0-60% at least one organic filler, 5-10% silicone-acrylic acid-based rubber impact modifier, 0-10% pigment, and 0.01-10% photoinitiator. The composition described in Patent Document 5 enables the production of denture devices with excellent stain resistance, chemical resistance, and solvent resistance. These curable compositions for three-dimensional stereolithography (hereinafter sometimes abbreviated as "stereolithography compositions") all contain a polymerizable monomer component and a polymer component, but are designed to prevent high viscosity. For example, in the stereolithography composition described in Patent Document 4, polymerized poly(methyl methacrylate) is formulated as a solution dissolved in methyl methacrylate (MMA), and the rubber impact modifier used in the stereolithography composition described in Patent Document 5 does not dissolve at room temperature or high temperatures, but swells and forms a colloid, and also has a core-shell structure.

[0010] JP-A No. 63-35508 JP-A No. 2008-214359 JP-A No. 6-78937 Special publication No. 2016-525150 Publication No. 2016-505525

[0011] Katakura, N. et al., Water absorption and dynamic viscoelasticity of denture base resins, Tohoku University Journal of Dental Science, 2004, Vol. 23, pp. 67-72

[0012] In Patent Document 4, poly(methyl methacrylate) with a molecular weight of 10,000 to 400,000, specifically 110,000 to 300,000, is blended into a stereolithography composition to enhance the mechanical properties of the resulting product. This requires the use of methyl methacrylate (MMA). Stereolithography compositions that also contain MMA not only have difficulty in long-term storage in a liquid bath (VAT) due to the high volatility of MMA, but also have odor problems. Furthermore, the stereolithography composition disclosed in Patent Document 5 requires the use of a rubber impact modifier to produce a cured product with high mechanical strength and excellent adhesive strength to acrylic plastic teeth. Furthermore, the stereolithography composition specifically disclosed in Patent Document 5 uses a monomer component containing MMA.

[0013] Furthermore, as mentioned above, dentures (denture bases) that have been used for a long period of time require improved fit through lining (base lining), and therefore are required to have good adhesion to the lining material. For various dental components manufactured using the liquid vat photopolymerization method, adhesion to the lining material or other equivalent components may be important, as in the case of bonding a lining material to a denture base. For dental components that are used in the oral cavity for a long period of time, such as denture bases, it is also important to ensure adhesion even after long-term use in the oral cavity.

[0014] However, with regard to denture bases made using the stereolithography compositions disclosed in Patent Documents 4 and 5, no evaluation has been conducted on the adhesive strength when a lining material is adhered to them, and naturally, the above adhesive strength when methyl methacrylate or a rubber impact modifier is not used is also unknown.

[0015] Patent Document 5 discloses that in addition to poly(methyl methacrylate): PMMA, crosslinked polymers such as highly crosslinked PMMA and crosslinked polyacrylate can be used as organic fillers. Organic fillers made of crosslinked polymers are insoluble in polymerizable monomer components. Therefore, if it is possible to maintain the dispersion state of the organic filler in the stereolithography composition, it is thought that it may be possible to manufacture denture bases with good adhesion to lining materials using stereolithography compositions that do not contain methyl methacrylate or rubber impact modifiers.

[0016] Based on this idea, the present inventors prepared cured products of a stereolithography composition containing no organic filler and a stereolithography composition containing a crosslinked polymer as an organic filler, and evaluated the adhesive strength to a lining material in order to investigate the effect of adding a crosslinked polymer. As a result, as shown in Comparative Examples 1 and 6 described below, in both cases, the adhesive strength to the lining material was sufficient immediately after modeling by stereolithography, but it was found that the cured products did not have sufficient adhesive strength after undergoing a thermal shock test 15,000 times to reproduce the state of a denture base (cured product) after long-term use.

[0017] The present invention has been made in view of the above circumstances, and aims to provide a curable composition for three-dimensional stereolithography that has shape reproducibility suitable for the production of dental parts by liquid vat photopolymerization, and that has excellent adhesion between the dental part and a lining material or other equivalent parts, even after the dental part has been used in the oral cavity for a long period of time, without the use of methyl methacrylate or a rubber impact modifier, and a method for producing dental parts using the same.

[0018] The above object can be achieved by the present invention, which provides a curable composition for three-dimensional optical fabrication, comprising: 100 parts by mass of a (meth)acrylate polymerizable monomer component (A) that contains a polyfunctional (meth)acrylate polymerizable monomer and does not contain methyl (meth)acrylate; 0.7 to 220 parts by mass of a monofunctional (meth)acrylate polymer (B) that has a number average molecular weight of 1,000 to 50,000 as measured by gel permeation chromatography; and a photopolymerization initiator (C).

[0019] In another embodiment of the three-dimensional stereolithography curable composition of the present invention, the three-dimensional stereolithography curable composition is preferably used for producing a dental part.

[0020] In another embodiment of the curable composition for three-dimensional stereolithography of the present invention, the dental part is preferably a denture base.

[0021] In another embodiment of the curable composition for three-dimensional optical modeling of the present invention, it is preferable that the curable composition for three-dimensional optical modeling consists of only the (meth)acrylate polymerizable monomer component (A), the monofunctional (meth)acrylate polymer (B), the photopolymerization initiator (C), and a pigment.

[0022] In another embodiment of the curable composition for three-dimensional optical fabrication of the present invention, it is preferable that the organic filler contains only the monofunctional (meth)acrylate polymer (B) and crosslinked polymethyl methacrylate.

[0023] In another embodiment of the curable composition for three-dimensional stereolithography of the present invention, the cured product preferably has a color tone selected from pink and white.

[0024] In the method for producing a dental part of the present invention, a dental part is produced using a cured product obtained by a liquid tank photopolymerization method using the curable composition for three-dimensional stereolithography of the present invention.

[0025] In one embodiment of the method for producing a dental article of the present invention, the dental article is preferably a denture base.

[0026] As described above, the present invention provides a curable composition for three-dimensional stereolithography that has shape reproducibility suitable for producing dental components by liquid tank photopolymerization without using methyl (meth)acrylate (MMA) or rubber impact modifiers, and that has excellent adhesion between the dental component and a lining material or other equivalent component even after the dental component has been used in the oral cavity for an extended period of time, and a method for producing dental components using the same.

[0027] Unless otherwise specified, in this specification, 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."

[0028] The rebasing operation is generally carried out according to the following procedure. First, the denture base is polished, and then an adhesive composition containing an organic solvent and a monomer is applied to the polished surface of the denture base to form a coating. The coating made of the adhesive composition is then dried to volatilize the organic solvent. Next, an uncured lining material is built up on the dried coating and formed into the desired shape, after which the lining material is cured together with the coating. This completes the lining operation.

[0029] Here, it is presumed that the following phenomenon occurs during the lining process using a conventional denture base prepared using a curable resin composition obtained by mixing a powder material and a liquid material. Specifically, when the adhesive composition is applied to the polished surface of the denture base, the monomer components of the adhesive composition, together with the organic solvent, penetrate into the non-crosslinked polymer (used as the powder material) exposed on the polished surface of the denture base. Furthermore, the subsequent evaporation of the organic solvent from the coating film made of the adhesive composition facilitates the penetration of the monomer components of the uncured built-up lining material into the non-crosslinked polymer (used as the powder material) exposed on the polished surface of the denture base. These two monomer components then harden within the non-crosslinked polymer exposed on the polished surface of the denture base. It is presumed that the above-described phenomenon not only improves the adhesive strength between the denture base and the built-up and cured lining material, but also maintains high adhesive strength even after long-term use in the oral cavity. The material that plays an important role in achieving the above-mentioned effect is the non-crosslinked polymer (derived from the powder material) contained in the conventional curable resin composition.

[0030] The inventors of the present invention have proposed that (1) the high adhesive strength of the stereolithography compositions (Comparative Examples 1 and 6) without a non-crosslinked polymer to the lining material immediately after modeling is due to a mechanism different from that described above, and (2) that a similar mechanism to that described above is necessary to enhance adhesive strength after long-term use. They also believed that if the above-described mechanism could be replicated in a curable composition for 3D stereolithography used to fabricate dental components such as denture bases, the excellent adhesive properties described above could also be replicated. To this end, the inventors prepared a composition that incorporates a typical 3D stereolithography curable composition containing a polyfunctional monomer as a main component, a component necessary for ensuring modeling ability, and further incorporates a non-crosslinked polymer with a weight-average molecular weight of several hundred thousand, which is also used in conventional curable resin compositions, and evaluated its adhesive properties. As a result, as shown in Comparative Example 5 described below, this composition exhibited excellent adhesive properties even in the cured product after 15,000 thermal shock tests, similar to conventional curable resin compositions, but the shape reproducibility was significantly reduced, confirming that it cannot be used for 3D stereolithography by liquid vat photopolymerization. Meanwhile, the present inventors also evaluated the typical curable compositions for 3D stereolithography described above that did not contain a non-crosslinked polymer. As a result, as shown in Comparative Example 1 (an example in which no organic filler, including a non-crosslinked polymer, was added) and Comparative Example 6 (an example in which only a crosslinked polymer was blended as an organic filler), the compositions of these comparative examples exhibited shape reproducibility suitable for 3D stereolithography using the liquid vat photopolymerization method, but the adhesive properties of the cured products after 15,000 thermal shock tests were extremely poor. These results suggest that the polymer (crosslinked polymer) of a polyfunctional monomer contained in the cured product of the curable composition for 3D stereolithography does not contribute to improving the adhesiveness of denture base linings after long-term use in the oral cavity.

[0031] Based on the above findings, the present inventors have discovered the following curable composition for three-dimensional stereolithography and a method for producing a dental part using the same.

[0032] 1. Curable Composition for Three-Dimensional Optical Fabrication The curable composition for three-dimensional optical fabrication of this embodiment includes 100 parts by mass of a (meth)acrylate polymerizable monomer component (A) that contains a polyfunctional (meth)acrylate polymerizable monomer and does not contain methyl (meth)acrylate, 0.7 to 220 parts by mass of a monofunctional (meth)acrylate polymer (B) that has a number average molecular weight of 1,000 to 50,000 as measured by gel permeation chromatography, and a photopolymerization initiator (C).

[0033] The curable composition for three-dimensional stereolithography of this embodiment has a fluidity suitable for producing dental parts by liquid vat photopolymerization, and also has excellent adhesion between the dental part and a lining material or other equivalent parts (hereinafter, sometimes referred to as a "lining material, etc.") even after the dental part has been used in the oral cavity for a long period of time. Although the details of why such excellent effects are obtained are unknown, the inventors speculate that the above-mentioned effects are obtained for the reasons explained below.

[0034] First, the reason why the curable composition for three-dimensional stereolithography of this embodiment has shape reproducibility suitable for stereolithography using a liquid tank photopolymerization method is due to the use of a monofunctional (meth)acrylate polymer (B) with an extremely low number-average molecular weight as the non-crosslinked polymer. When a composition contains a (meth)acrylate-based polymerizable monomer component and a monofunctional (meth)acrylate polymer with a high molecular weight, as in Comparative Example 1 described below, the viscosity of the composition increases significantly due to entanglement of long-chain molecules of the monofunctional (meth)acrylate polymer swollen by the (meth)acrylate-based polymerizable monomer component. However, the curable composition for three-dimensional stereolithography of this embodiment uses a monofunctional (meth)acrylate polymer with an extremely low molecular weight (i.e., a polymer with a short molecular chain) as the non-crosslinked polymer instead of a monofunctional (meth)acrylate polymer with a high molecular weight. This suppresses entanglement between polymers of monofunctional (meth)acrylates with very small molecular weights (i.e., short-chain molecules), and as a result, the curable composition for three-dimensional photopolymerization of this embodiment has the high fluidity necessary to ensure shape reproducibility.

[0035] Furthermore, as described above, the excellent adhesiveness is believed to be due to the non-crosslinked polymer contained in the composition. The non-crosslinked polymer contained in the dental component, such as a denture base, is believed to serve as a base for the penetration and curing of the monomers contained in the adhesive composition and lining material, thereby improving adhesiveness. Considering these points, it can be said that the number of molecules of the non-crosslinked polymer serving as the base is more important than the molecular chain length for improving adhesiveness. Therefore, in the curable composition for three-dimensional optical fabrication of this embodiment, a monofunctional (meth)acrylate polymer with a very small molecular weight is used as the non-crosslinked polymer, so that a large number of molecules, i.e., excellent adhesiveness, can be easily obtained even with a relatively small amount of non-crosslinked polymer blended.

[0036] Next, each component used in the curable composition for three-dimensional optical fabrication of this embodiment will be described in detail below.

[0037] (1) (Meth)acrylate-Based Polymerizable Monomer Component (A) The (meth)acrylate-based polymerizable monomer component (A) used in the 3D stereolithography curable composition of this embodiment refers to a component that contains a polyfunctional (meth)acrylate-based polymerizable monomer but does not contain methyl (meth)acrylate. Because methyl (meth)acrylate (MMA) is highly volatile, 3D stereolithography curable compositions containing MMA are difficult to store in a liquid tank (VAT) for long periods of time and suffer from odor problems. Furthermore, 3D stereolithography curable compositions that do not contain a polyfunctional (meth)acrylate-based polymerizable monomer are difficult to produce cured products with good mechanical properties, such as strength and durability.

[0038] As the polyfunctional (meth)acrylate polymerizable monomer, any polyfunctional (meth)acrylic acid polymerizable monomer that is generally used in dentistry and is liquid at room temperature (e.g., 25°C) can be used without any particular limitation. Suitable polyfunctional (meth)acrylate polymerizable monomers (A) that can be used include 1,6-bis(methacrylethyloxycarbonylamino)trimethylhexane, 2,2-bis(methacryloyloxyphenyl)propane, and acrylates corresponding to these methacrylates, such as 2-hydroxyethyl(meth)acrylate, 2-hydroxypropyl(meth)acrylate, 3-chloro-2-hydroxypropyl(meth)acrylate, ethylene glycol di(meth)acrylate, and triethylene glycol. Examples of suitable (meth)acrylic acid polymerizable monomers include difunctional (meth)acrylic acid polymerizable monomers such as di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, and 2-hydroxyethyl (meth)acrylate, and trifunctional (meth)acrylic acid polymerizable monomers such as trimethylolpropane tri(meth)acrylate, trimethylolethane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, and trimethylolmethane tri(meth)acrylate. These polyfunctional (meth)acrylic acid polymerizable monomers can be used alone or in combination of two or more.

[0039] The (meth)acrylate polymerizable monomer component (A) may contain a monofunctional (meth)acrylate polymerizable monomer other than methyl (meth)acrylate (MMA). Suitable examples of the monofunctional (meth)acrylate polymerizable monomer include ethyl (meth)acrylate, hydroxyethyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, 2-methacryloxyethyl propionate, and acetoacetoxyethyl (meth)acrylate.

[0040] When a monofunctional (meth)acrylate polymerizable monomer is further used as the (meth)acrylate polymerizable monomer component (A), from the viewpoint of enabling the curable composition for three-dimensional photo-fabrication to be stored in a liquid tank (VAT) for a long period of time and from the viewpoint of mechanical properties such as strength and durability of the three-dimensional photo-fabricated object (cured product), the content of the polyfunctional (meth)acrylate polymerizable monomer in the total amount of the (meth)acrylate polymerizable monomer component (A) consisting of the polyfunctional (meth)acrylate polymerizable monomer (A) and the monofunctional (meth)acrylate polymerizable monomer is preferably 30% by mass or more and less than 100% by mass, and more preferably 50% by mass or more and less than 100% by mass.

[0041] (2) Monofunctional (meth)acrylate polymer (B) The curable composition for 3D stereolithography of this embodiment uses a monofunctional (meth)acrylate polymer (B) having a number average molecular weight (Mn) of 1,000 to 50,000 as a non-crosslinked polymer, which is a type of organic filler, as measured by gel permeation chromatography. Here, "monofunctional" means that the molecule contains one (meth)acryloyl group as a radically polymerizable group. The number average molecular weight refers to the number average molecular weight calculated as a standard polymer using polystyrene (PS) as the standard polymer.

[0042] When the number-average molecular weight of the monofunctional (meth)acrylate polymer (B) exceeds 50,000, even a small amount of the monofunctional (meth)acrylate polymer (B) significantly increases the viscosity of the curable composition for 3D stereolithography, making it difficult to achieve excellent shape reproducibility. Furthermore, when the number-average molecular weight is less than 1,000, not only is it difficult for the monofunctional (meth)acrylate polymer (B) to entangle with components derived from the lining material, but the monofunctional (meth)acrylate polymer (B) is also more likely to volatilize from the curable composition for 3D stereolithography stored in a liquid bath (VAT) for a long period of time, resulting in reduced adhesion. The number-average molecular weight is preferably 2,000 to 30,000, more preferably 3,000 to 10,000, because this facilitates a good balance between excellent adhesion due to the increased entanglement of the monofunctional (meth)acrylate polymer (B) with components derived from the lining material, and excellent shape reproducibility due to the moderate fluidity of the curable composition for 3D stereolithography.

[0043] The amount of monofunctional (meth)acrylate polymer (B) blended is 0.7 to 220 parts by weight, preferably 1 to 200 parts by weight, more preferably 5 to 100 parts by weight, and even more preferably 10 to 80 parts by weight, per 100 parts by weight of the (meth)acrylate-based polymerizable monomer component (A). If the blending amount exceeds 220 parts by weight, the compatibility of components (B) and (A) becomes poor, making it difficult to uniformly mix the two components. Furthermore, the fluidity of the curable composition for three-dimensional stereolithography decreases, making it difficult to achieve excellent shape reproducibility. Furthermore, if the blending amount is less than 0.7 parts by weight, sufficient adhesive strength cannot be obtained.

[0044] The monofunctional (meth)acrylate polymer (B) may be used alone or in combination of two or more kinds, but from the viewpoint of ease of synthesis, it is preferable to use only one kind. The monofunctional (meth)acrylate polymer (B) is a compound represented by the general formula: H ２ C=C(R １ )-C(=O)-OR ２ In the above general formula, R １ represents a methyl group or a hydrogen atom, R ２ represents a substituent having no polymerizable functional group, specifically an alkyl group having 1 to 10 carbon atoms, a benzyl group, an isobornyl group, or a tetrahydrofurfuryl group. R ２ is preferably an alkyl having 1 to 4 carbon atoms, and most preferably methyl. The monofunctional (meth)acrylate polymer (B) may be a polymer polymerized using various modified (meth)acrylates having a modified structure selected from the group consisting of a urethane skeleton, a silicone skeleton, a polyester skeleton, a polyamide skeleton, a phenol skeleton, etc. introduced into the molecule, or may be a polymer polymerized using a (meth)acrylate that does not contain these modified structures. The monofunctional (meth)acrylate polymer (B) is a particle having a single-layer structure.

[0045] Furthermore, since the monofunctional (meth)acrylate polymer (B) is a non-crosslinked polymer that does not have a crosslinked structure, it usually exists as particulate aggregates in which linear non-crosslinked polymers are entangled. In the curable composition for three-dimensional optical fabrication of this embodiment, the form in which the component (B) exists is not particularly limited, and aggregates of the component (B) may remain, or the polymer chains constituting the aggregates may be dissociated and dispersed.

[0046] (3) Photopolymerization Initiator (C) The photopolymerization initiator (C) generates radicals in response to activation light containing light of a specific wavelength λ (nm) in the ultraviolet or visible light range irradiated from a light source installed in the stereolithography device, thereby radically polymerizing the (meth)acrylate polymerizable monomer component (A) and other polymerizable monomers used as needed. Therefore, the photopolymerization initiator must absorb light of the specific wavelength λ (nm) to generate radicals. The specific wavelength λ can be determined appropriately depending on the wavelength of the activation light used in the stereolithography device, as long as it is within the ultraviolet or visible light range. General-purpose stereolithography devices include SLA-type stereolithography devices that irradiate photocurable resins with semiconductor laser light, DLP-type stereolithography devices that irradiate projector light, and LCD-type stereolithography devices that irradiate liquid crystal panel light. In these stereolithography devices, light sources with wavelengths of approximately 405 nm or 385 nm are often used as the source of activation light. Therefore, in the stereolithography using the curable composition for three-dimensional stereolithography of this embodiment, it is preferable to use activating light containing light with a specific wavelength λ of 405 nm or 385 nm. In this case, the stereolithography device used is preferably an SLA, DLP, or LCD stereolithography device.

[0047] The photopolymerization initiator can be appropriately selected from known photopolymerization initiators depending on the wavelength of the activating light used in stereolithography. Specific examples of the photopolymerization initiator include self-cleavage photopolymerization initiators, bimolecular hydrogen abstraction photopolymerization initiators, photoacid generators, and combinations thereof. These photopolymerization initiators may also be used in combination with photosensitizing dyes, electron-donating compounds, etc.

[0048] Examples of the self-cleavage type photopolymerization initiator that can be suitably used 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.

[0049] 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.

[0050] Examples of photosensitizing dyes that can be used 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 such as anthracene and perylene, and thioxanthone compounds. Examples of electron donating compounds include 4-dimethylaminobenzoic acid esters, 4-dimethylaminotoluene, p-dimethoxybenzene, 1,2,4-trimethoxybenzene, and thiophene compounds.

[0051] The amount of the photopolymerization initiator is not particularly limited as long as it is an amount that allows sufficient photolithography (photopolymerization) when the curable composition for three-dimensional optical modeling is irradiated with activating light, and can be appropriately selected depending on the type of photopolymerization initiator used, etc. However, typically, the amount is preferably 0.05 to 5 parts by mass, and more preferably 0.1 to 3 parts by mass, per 100 parts by mass of the (meth)acrylate polymerizable monomer component (A).

[0052] (4) Other Components The curable composition for three-dimensional optical fabrication of this embodiment may further contain other components in addition to components (A) to (C) as needed. Examples of other components include (i) inorganic fillers consisting of inorganic powders and particles such as calcium carbonate, magnesium oxide, barium sulfate, titanium oxide, potassium titanate, aluminum hydroxide, silica powder, glass powder, diatomaceous earth, silica, calcium silicate, talc, alumina, mica, and quartz glass, (ii) organic-inorganic composite fillers consisting of powders and particles obtained by pulverizing a cured product obtained by polymerizing and curing a paste-like composition containing an inorganic filler and a polymerizable monomer, (iii) organic fillers other than component (B), (iv) polymerization inhibitors such as butylhydroxytoluene and methoxyhydroquinone, (v) ultraviolet absorbers such as 4-methoxy-2-hydroxybenzophenone and 2-(2-benzotriazole)-p-cresol, (vi) polymerization modifiers such as α-methylstyrene dimer, (vii) dyes (excluding the photosensitizing dyes described above), (viii) pigments, and (ix) fragrances. Furthermore, (x) a thermal polymerization initiator may be used for secondary curing.

[0053] Furthermore, in the curable composition for 3D stereolithography of this embodiment, component (B) (a non-crosslinked polymer) is used as the organic filler. However, other organic fillers composed of polymers (resins) other than component (B) may also be used. In this case, it is preferable to use a polymer having a crosslinked structure (crosslinked polymer) as the other organic filler. This prevents the viscosity of the curable composition for 3D stereolithography of this embodiment, to which the other organic filler has been added, and easily ensures shape reproducibility suitable for producing dental parts using the liquid tank photopolymerization method. Known crosslinked polymers can be used as the other organic filler without any particular restrictions. However, from the perspective of easy availability, it is preferable to use a crosslinked acrylate resin such as crosslinked polymethyl methacrylate (PMMA). Furthermore, the other organic filler used in the curable composition for 3D stereolithography of this embodiment may be particles having a multilayer structure such as a core-shell structure, but particles having a single layer structure are usually preferred. In this specification, unless the structure of the organic filler is specifically described, the organic filler refers to particles having a single layer structure. Furthermore, as the organic filler, a rubber impact modifier having a silicone-acrylic acid-based core-shell structure as described in Patent Document 5 can also be used. However, for reasons such as cost-effectiveness and difficulty in obtaining such a modifier, it is preferable not to use such a rubber impact modifier.

[0054] Although two or more of the other components listed above can be used in combination, it is preferable to use at least a pigment, and the only other component may be a pigment. In this case, the curable composition for 3D stereolithography of this embodiment may be composed only of component (A), component (B), component (C), and the pigment. In this case, the pigment content is preferably 0.005% to 0.2% by mass, more preferably 0.01% to 0.1% by mass, based on the total mass of the curable composition for 3D stereolithography. Furthermore, the cured product of the curable composition for 3D stereolithography of this embodiment preferably has a pinkish color. This is because the cured product is used as a dental component, particularly a dental prosthesis such as a denture base used in the oral cavity, and therefore preferably has a color similar to that of the oral mucosa. Alternatively, the cured product of the curable composition for 3D stereolithography of this embodiment preferably has a whiteish color. In this case, the dental component can be used as an artificial tooth. In addition, when reproducing a pinkish color tone, a pink pigment and / or a red pigment is mainly used as the pigment, and a white pigment and / or a pigment of another color may be further used in combination as needed to adjust the color tone, and when reproducing a whiteish color tone, a white pigment is mainly used, and a pigment of another color may be further used in combination as needed to adjust the color tone.

[0055] 2. Uses of the 3D stereolithography curable composition: The 3D stereolithography curable composition of the present embodiment is used to produce dental parts using a liquid tank photopolymerization method. Dental parts produced using the 3D stereolithography curable composition of the present embodiment include various dental prostheses used in the oral cavity, with denture bases being particularly suitable. Furthermore, when a dental part is composed of multiple components, some or all of the components constituting the dental part may be produced using the 3D stereolithography curable composition of the present embodiment. For example, when producing a denture consisting of a denture base and artificial teeth held and fixed to the denture base as a dental part, only the denture base can be produced using the 3D stereolithography curable composition of the present embodiment, and artificial teeth produced by another method can be attached to the denture base to produce the denture. On the other hand, when producing a denture as a dental component, which is composed of a single component in which the denture base and artificial teeth are integrally molded, the entire denture can also be produced as a single piece using the curable composition for three-dimensional photopolymerization of this embodiment.

[0056] The dental part fabricated using the curable composition for 3D stereolithography of this embodiment is used in a form in which it is adhered to a lining material or other equivalent member using an adhesive composition containing at least a monomer and an organic solvent. Here, "other member corresponding to the lining material" means a member that shares a main component with the lining material, i.e., a member containing a (meth)acrylate monomer and a non-crosslinked polymer as main components.

[0057] 3. Method for Preparing Curable Composition for Three-Dimensional Optical Fabrication The curable composition for three-dimensional optical fabrication of this embodiment can be prepared by weighing out predetermined amounts of components (A), (B), and (C), and other components used as needed, and then appropriately mixing the components. The resulting liquid or paste-like curable composition for three-dimensional optical fabrication is preferably stored in a light-blocking container to prevent deterioration during storage.

[0058] 4. Method for Producing Dental Parts In the method for producing dental parts of this embodiment, a dental part such as a denture base is produced using a cured product obtained by liquid tank photopolymerization using the curable composition for 3D stereolithography of this embodiment. The method for producing dental parts of this embodiment includes: (i) a process for producing a cured product when the dental part to be produced is the cured product of the curable composition for 3D stereolithography itself; and (ii) a process for producing a dental part using the cured product and other components constituting the dental part when one component of the dental part to be produced is the cured product of the curable composition for 3D stereolithography. In both (i) and (ii), the process for producing the cured product involves photolithography using liquid tank photopolymerization. A specific example of (i) is when the dental part to be produced is a denture base. A specific example of (ii) is when the dental part to be produced is a denture base and an artificial tooth held and fixed in the denture base. In this case, for example, a cured product prepared by the liquid vat photopolymerization method is used as a denture base. Then, commercially available artificial teeth (rows) or artificial teeth (rows) prepared using a 3D printer or cutting machine are attached to this denture base using an adhesive, and then polished as necessary to produce a denture.

[0059] The basic process of stereolithography using liquid vat photopolymerization includes at least the following steps: forming a modeling layer (corresponding to a portion of the cured product) by irradiating a portion of the curable composition for 3D stereolithography of the present embodiment held in a vat with activating light to harden it, based on shape data of (a) a dental member or (b) a member constituting a portion of the dental member to be stereolithographed (hereinafter, both members (a) and (b) may be referred to as the "stereolithography target"); and forming a laminate (cured product) by sequentially stacking the modeling layers by repeating the modeling layer-forming step. These steps can also be combined with other steps as needed.

[0060] A more specific example of a photo-lithography process using the liquid vat photopolymerization method includes a two-dimensional shape data generation process, a laminate formation process, a cleaning process, and a secondary curing process, which are described below.

[0061] (1) Two-dimensional shape data generation process: In the two-dimensional shape data generation process, the height position information of the photo-printing object is digitized from the three-dimensional shape data representing the shape of the photo-printing object, and the information is ranked from one side to the other in the height direction, and two-dimensional shape data representing the cross-sectional shape of the photo-printing object at each ranked height position is generated.

[0062] (2) Laminate formation process: In the laminate formation process, the curable composition for three-dimensional photo-polymerization of this embodiment held in a tank is irradiated with activation light at a position corresponding to the two-dimensional shape data, thereby selectively curing a portion of the curable composition for three-dimensional photo-polymerization to form a modeling layer. The modeling layers are then sequentially formed and stacked in the order in which the height position information of the object to be modeled is ranked, thereby forming a laminate having a shape corresponding to the three-dimensional shape data.

[0063] (3) Cleaning step: In the cleaning step, the laminate is cleaned using an organic solvent. (4) Secondary curing step: In the secondary curing step, the cleaned laminate is subjected to at least one curing treatment selected from a second irradiation treatment with activating light and a heat treatment, thereby secondary curing the laminate.

[0064] By carrying out these steps in sequence, the secondary cured laminate can be obtained as the desired (a) dental part or (b) part constituting a part of a dental part.

[0065] In the liquid tank photopolymerization method, the formation of a laminate can be carried out using a commercially available liquid tank photopolymerization device known as a 3D printer. Compact, hanging (inverted) devices are often used as liquid tank photopolymerization devices, and the formation of a laminate using such a device is generally carried out using the following procedure. First, a platform serving as the base of the laminate is placed in a tank filled with a curable composition for 3D stereolithography. The platform's underside is positioned at a height equivalent to one modeling layer (also known as the layer pitch; typically, the thickness of one layer is approximately 0.01 mm to 0.1 mm) from the bottom of the tank. In this state, activation light is irradiated from a light source located below the tank onto the curable composition for 3D stereolithography present between the bottom of the platform and the bottom of the tank, forming one modeling layer. The platform with the modeling layer attached to its underside is then moved upward, and the curable composition for 3D stereolithography present around the tank is poured between the modeling layer and the bottom of the tank. Next, the lower surface of the modeling layer attached to the platform is positioned at a height corresponding to the layer pitch from the bottom of the tank, and activating light is applied to form the next modeling layer. Note that when the platform is moved upward after forming the modeling layer, it may be moved upward by one layer (layer pitch), or it may be moved further, and the height of the lower surface of the modeling layer attached to the platform may be adjusted after the curable composition for three-dimensional optical modeling is poured in.

[0066] The laminate is formed by repeating one cycle of (i) setting the height position (position adjustment) of the underside of the platform or the underside of the modeling layer attached to it, (ii) forming the modeling layer by irradiating it with activating light, (iii) moving the platform upward, and (iv) flowing the curable composition for three-dimensional photo-modeling between the bottom of the tank and the underside of the modeling layer attached to the platform.

[0067] Examples of organic solvents that can be used in the washing step include alcoholic solvents such as ethanol, methanol, and isopropyl alcohol, ketone solvents such as acetone and methyl ethyl ketone, ether solvents such as diethyl ether, diisopropyl ether, tripropylene glycol monomethyl ether, and tetrahydrofuran, amide solvents such as N-methylpyrrolidone and dimethylacetamide, and halogenated solvents such as methylene chloride and chloroform. Among these, alcoholic and etheric solvents are preferred because of their high washing efficiency, and alcoholic solvents are preferred from the viewpoint of environmental friendliness.

[0068] In addition, in the secondary curing step, secondary curing can be performed, for example, by performing a second irradiation with activating light. The wavelength of the activating light when performing the second irradiation with activating light is not particularly limited as long as it is a wavelength at which the photopolymerization initiator remaining in the laminate generates radicals. Furthermore, when a thermal polymerization initiator is added to the curable composition for three-dimensional optical modeling of this embodiment, secondary curing can also be performed by heating the laminate.

[0069] The present invention will be explained in more detail below with reference to examples, but the present invention is not limited to these examples.

[0070] I. Raw Materials First, the names, characteristics, abbreviations (when abbreviations are used), etc. of the various compounds used in each example and comparative example are shown.

[0071] 1. Polymerizable Monomers The following polyfunctional (meth)acrylate polymerizable monomers were used as polymerizable monomers: 3G: triethylene glycol dimethacrylate UDMA: 1,6-bis(methacrylethyloxycarbonylamino)trimethylhexane

[0072] 2. Organic Filler As the organic filler, polymers (non-crosslinked polymers) of monofunctional (meth)acrylates listed in Table 1 below and crosslinked polymers described below were prepared.

[0073] (1) Monofunctional (meth)acrylate polymer (non-crosslinked polymer) The abbreviations, components, and number average molecular weights of the monofunctional (meth)acrylate polymers used are shown in Table 1. PMMA-AA6, PBA, and PMMA-D350ML3A are compounds corresponding to the monofunctional (meth)acrylate polymer (B) having a number average molecular weight of 1,000 to 50,000.

[0074]

[0075] (2) Cross-linked poly(meth)acrylate (cross-linked polymer) - MBX-8: Cross-linked methyl methacrylate polymer (manufacturer: Sekisui Plastics Co., Ltd.)

[0076] 3. Photopolymerization initiator (C) BTPO: bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide.

[0077] II. Preparation and Evaluation Results of Curable Compositions for Three-Dimensional Stereolithography (Example 1) A curable composition for three-dimensional stereolithography was prepared by mixing the components according to the composition shown in Table 2. The shape reproducibility (applicability to the liquid tank photopolymerization method) of the obtained curable composition for three-dimensional stereolithography was evaluated, and the adhesiveness of the cured composition to a backing material after a thermal shock test (also simply referred to as "adhesion after thermal shock resistance test") was evaluated. The results are shown in Table 3.

[0078] Examples 2 to 8 Shape reproducibility and adhesion after a thermal shock resistance test were evaluated in the same manner as in Example 1, except that the formulation of the curable composition for three-dimensional stereolithography was changed as shown in Table 2. The results are shown in Table 3.

[0079] Comparative Examples 1 to 6 Except for changing the composition of the curable composition for three-dimensional stereolithography as shown in Table 2, the shape reproducibility and the adhesion after the thermal shock resistance test were evaluated in the same manner as in Example 1. The results are shown in Table 3.

[0080]

[0081]

[0082] III. Evaluation Methods The methods for evaluating the adhesiveness and shape reproducibility after the thermal shock resistance test shown in Table 3 are as follows.

[0083] <Evaluation of Adhesion After Thermal Shock Resistance Test> The prepared 3D stereolithography curable composition was filled into a through-hole (length and width: 15 mm x 15 mm, through-hole length: 5 mm) provided in an SUS mold, and both openings of the filled through-hole were pressed with silicone sheets. In this state, the 3D stereolithography curable composition in the through-hole was irradiated with light for 30 minutes using a dental laboratory photopolymerization device, Alpha Light V (manufactured by MORITA Corporation), to produce a cured product. The resulting cured product was polished with #800 waterproof abrasive paper, placed in a thermal shock tester, and immersed in a 5°C water bath for 30 seconds, then transferred to a 55°C water bath and immersed in a 55°C water bath for 30 seconds. This cycle was repeated 15,000 times. The thermal shock test on such a cured product simulated the conditions of long-term use of the cured product (dental component) in the oral cavity, where hot and cold food and beverages repeatedly pass through.

[0084] Next, the cured product removed from the thermal shock tester was polished again with #800 waterproof abrasive paper, and an adhesive composition containing a monomer and a volatile organic solvent as main components (volatile rebase adhesive, manufactured by Tokuyama Dental Co., Ltd.) was applied to one side of the cured product and dried. Then, a double-sided tape with a 3 mm diameter hole was fixed to the applied surface, and then a paraffin wax (0.5 mm thick) with an 8 mm diameter hole was fixed so that the center points of the hole in the double-sided tape and the hole in the paraffin wax were aligned. Next, a small amount of a mixture of the powder material and liquid material constituting the lining material (Rebase III, manufactured by Tokuyama Dental Co., Ltd.) was placed in the hole in the paraffin wax, and the mixture placed in the hole was pressed against an acrylic plate via a polyester film and left to stand for 2 minutes. The cured product with the lining material (mixture) adhered to one side via the adhesive composition was stored in a 37°C constant temperature bath for 30 minutes, thereby curing the lining material (mixture) together with the adhesive composition, and a cured sample was obtained. Thereafter, the paraffin wax and polyester film were peeled off from the cured sample, and the cured sample was further immersed in water at 37° C. overnight, thereby obtaining a measurement sample.

[0085] A test specimen was prepared by adhering a metal attachment (polished with #320 waterproof abrasive paper) to the lining material (cured mixture) of the measurement sample using Model Repair (Dentsply). The test specimen was then mounted on an autograph "AG-1" (Shimadzu Corporation) and subjected to a tensile test at a crosshead speed of 2 mm / min to measure the tensile strength. The average tensile strength of the five test specimens was calculated as the tensile strength shown in Table 3.

[0086] <Evaluation of Shape Reproducibility During Stereolithography (Evaluation of Applicability to Liquid Vacuum Photopolymerization)> Whether the curable compositions for 3D stereolithography of each Example and Comparative Example were suitable for producing dental parts by liquid vat photopolymerization was evaluated based on the reproducibility of the shape of a maxillary denture base produced by the procedure described below (reproducibility of 3D data used for stereolithography). If a curable composition for 3D stereolithography has fluidity suitable for stereolithography by liquid vat photopolymerization, the reproducibility of the shape of the produced maxillary denture base will also be high. Therefore, a curable composition for 3D stereolithography that has a high evaluation of shape reproducibility during stereolithography can be said to be highly applicable to the liquid vat photopolymerization method and to have fluidity suitable for liquid vat photopolymerization.

[0087] First, a curable composition for 3D stereolithography was supplied to each resin tray (tank) of an SLA-type 3D printer (Form2 manufactured by Formlabs, wavelength: 405 nm, irradiation intensity: 250 mW) and an LCD-type 3D printer (SOLPlus manufactured by ACKURETTA, wavelength: 405 nm). Next, stereolithography data (3D data consisting of STL data) of the maxillary denture base shape, the maxillary denture raft shape, and the support shape connecting the rafts was used to produce a molded body (laminate) with a layered structure (composed of a cured product of the curable composition for 3D stereolithography having a shape corresponding to the above shape).

[0088] The resulting molded body was then washed for 20 minutes in a 3D printer laminate cleaning machine filled with isopropyl alcohol (Form Wash, manufactured by Formlabs; Clean with Tank Plus, manufactured by ACKURETTA). The molded body was then subjected to a second 30-minute light irradiation using a secondary curing machine (Form Cure, manufactured by Formlabs; Curie Plus, manufactured by ACKURETTA). The raft and support were then removed from the molded body to produce a three-dimensional photo-fabricated object.

[0089] The appearance of the produced three-dimensional stereolithography objects was visually observed to confirm whether there were any defects in the external shape. Furthermore, for three-dimensional stereolithography objects in which no significant defects were observed in the external shape, the 3D data of the maxillary denture base shape used to produce the molded body and the 3D data obtained by scanning the three-dimensional stereolithography object with a 3D scanner-type coordinate measuring machine (Keyence Corporation: VL-500 Series) were compared in shape using the VL-500 Series application software (Keyence Corporation), and the difference between the maximum and minimum deviations was recorded as the contour accuracy. Then, based on visual observation or contour accuracy, shape reproducibility was evaluated using the following evaluation criteria. Table 3 shows the shape reproducibility evaluation results as an evaluation result for the applicability of the liquid tank photopolymerization method. A: Three stereolithography runs were performed, and stereolithography proceeded without any defects all the way to the final layer, with the average contour accuracy for each run being less than 2.0 mm. B: Stereolithography was performed three times, and in each case, the stereolithography proceeded without any defects up to the final layer, and the average contour accuracy for each was 2.0 mm or more. C: Stereolithography was performed three times, and part or all of the denture base was missing in at least one case. D: Stereolithography was performed three times, and part or all of the denture base was missing in each case.

[0090] IV. Discussion of Evaluation Results In all of Examples 1 to 8, the components were blended to satisfy the structure of the curable composition for 3D stereolithography of this embodiment. All of the Examples exhibited high adhesive strength and shape reproducibility. In contrast, Comparative Example 1, which does not contain a polymer of (B) monofunctional (meth)acrylate, possessed fluidity suitable for stereolithography and thus achieved high shape reproducibility, but exhibited low tensile strength. Although not shown in the table, the adhesive properties of a cured product prepared in the same manner as Comparative Example 1 were evaluated without conducting a thermal shock test to simulate the condition of a cured product used in the oral cavity for a long period of time. The tensile strength was a high value of 11.7 MPa.

[0091] Comparative Example 2 was a composition in which the amount of (B) monofunctional (meth)acrylate polymer was set to a high level (250 parts by mass). Although the tensile strength was high, the fluidity was low, resulting in partial chipping of the stereolithographically fabricated denture base, making it unsuitable for stereolithography. Comparative Example 3 was a composition in which the amount of (B) monofunctional (meth)acrylate polymer was set to an even higher level (350 parts by mass). Although the tensile strength was high, the fluidity was extremely low, making it impossible to stereolithograph the denture base at all. Comparative Example 4 was a composition in which the monofunctional (meth)acrylate polymer was a copolymer of methyl methacrylate and ethyl methacrylate with a number-average molecular weight of approximately 140,000, exceeding 50,000. Although the tensile strength was high, the fluidity was low, resulting in partial chipping of the stereolithographically fabricated denture base, making it unsuitable for stereolithography. Comparative Example 5 was a composition that incorporated a common polymethyl methacrylate with a number-average molecular weight of approximately 800,000 to 1,000,000 as the monofunctional (meth)acrylate polymer, and although it had a high tensile strength, it had extremely low fluidity and was unable to form a denture base using photolithography. Furthermore, Comparative Example 6 was a composition that incorporated a crosslinked poly(meth)acrylate instead of the (B) monofunctional (meth)acrylate polymer, and although the tensile strength of the cured product that did not undergo the thermal shock test was high at 7.0 MPa as in Comparative Example 1, the tensile strength of the cured product that underwent the thermal shock test was low, as shown in Table 3.

Claims

1. A curable composition for three-dimensional stereolithography, comprising: 100 parts by mass of a (meth)acrylate polymerizable monomer component (A) that contains a polyfunctional (meth)acrylate polymerizable monomer and does not contain methyl (meth)acrylate; 0.7 to 220 parts by mass of a monofunctional (meth)acrylate polymer (B) that has a number average molecular weight of 1,000 to 50,000 as measured by gel permeation chromatography; and a photopolymerization initiator (C).

2. The curable composition for three-dimensional stereolithography according to claim 1, which is used to produce dental parts.

3. The curable composition for three-dimensional stereolithography according to claim 2, wherein the dental part is a denture base.

4. The curable composition for three-dimensional optical modeling according to claim 1, which consists only of the (meth)acrylate polymerizable monomer component (A), the monofunctional (meth)acrylate polymer (B), the photopolymerization initiator (C), and a pigment.

5. The curable composition for three-dimensional optical shaping according to claim 1, which contains only the polymer (B) of the monofunctional (meth)acrylate and crosslinked polymethyl methacrylate as the organic filler.

6. The curable composition for three-dimensional stereolithography according to claim 1, wherein the cured product has a color tone selected from the group consisting of pink and white.

7. A method for producing a dental part, comprising producing a dental part using a cured product obtained by a liquid tank photopolymerization method using the curable composition for three-dimensional stereolithography according to claim 1.

8. The method for producing a dental part according to claim 7, wherein the dental part is a denture base.

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