Photocurable compositions, three-dimensional molded objects, and instruments worn in the oral cavity.

Abstract

Provided is a photocurable composition comprising: a (meth)acrylic monomer (A) that has two urethane bonds and two (meth)acryloyl groups, each of the two (meth)acryloyl groups being joined to each of the two urethane bonds via a C4-10 alkylene group having bonded thereto an oxygen atom or a nitrogen atom; a (meth)acrylic monomer (B) having one (meth)acryloyl group; and a photopolymerization initiator.

Description

Technical Field

[0001] The present disclosure relates to a photocurable composition, a three-dimensional shaped object, and an appliance worn in the oral cavity.

Background Art

[0002] In recent years, studies have been made on dental products such as dental prostheses and appliances used in the oral cavity. For example, from the viewpoint of the efficiency of shaping these dental products, a method of manufacturing a three-dimensional shaped object such as a dental product by optical shaping using a 3D printer is known (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When a three-dimensional shaped object manufactured by optical shaping using a photocurable composition is used for an appliance worn in the oral cavity such as a denture base or a splint, in addition to a certain bending strength and bending elastic modulus, a certain toughness is required. In addition, the three-dimensional shaped object manufactured by optical shaping may be washed with isopropyl alcohol after shaping, but the toughness of the three-dimensional shaped object may be reduced by the washing, and sufficient toughness may not be obtained.

[0005] An object of one aspect of the present disclosure is to provide a photocurable composition capable of manufacturing a three-dimensional shaped object having high toughness even after washing with isopropyl alcohol, a three-dimensional shaped object obtained from this photocurable composition, and an appliance worn in the oral cavity.

Means for Solving the Problems

[0006] The means for solving the above problems include the following aspects. <1> (Meth)acrylic monomer (A) having two urethane bonds and two (meth)acryloyl groups, each of the two (meth)acryloyl groups being linked to each of the two urethane bonds via a C4-C10 alkylene group to which an oxygen or nitrogen atom is bonded, A (meth)acrylic monomer (B) having one (meth)acryloyl group, A photocurable composition comprising a photopolymerization initiator. <2> The (meth)acrylic monomer (A) is a compound represented by the following general formula (A-1): <1> The photocurable composition described in [reference].

[0007] [ka]

[0008] (In formula (A-1), R 1A It is a divalent hydrocarbon group, R 2A and R 3A Each of these is an alkylene group having 4 to 10 carbon atoms, and R 4A and R 5A These are, independently, either a methyl group or a hydrogen atom. <3> In the above general formula (A-1), R 1A However, it is a divalent hydrocarbon group with 5 to 20 carbon atoms. <2> The photocurable composition described in [reference]. <4> In the above general formula (A-1), R 1A However, the base is represented by one of the following general formulas (a-1) to (a-7), <2> The photocurable composition described in [reference].

[0009] [ka]

[0010] (In equations (a-1) to (a-7), * indicates the bonding position.) <5> The photocurable composition according to any one of <1> to <4>, wherein the (meth)acrylic monomer (B) is at least one of a compound represented by the following general formula (B-1) and a compound represented by the following general formula (B-2).

[0011] [Chemical formula]

[0012] (In formula (B-1), R 1B1 is a monovalent organic group having one or more selected from the group consisting of an aromatic ring, a hydroxy group, and a carboxy group, and R 2B1 is a methyl group or a hydrogen atom. In formula (B-2), R 1B2 and R 2B2 are each independently a monovalent organic group, and R 1B2 and R 2B2 may be bonded to each other to form a ring, and R 3B2 is a methyl group or a hydrogen atom.) <6> The photocurable composition according to any one of <1> to <5>, wherein the molecular weight of the (meth)acrylic monomer (A) is 440 to 650. <7> The photocurable composition according to any one of <1> to <6>, wherein the molecular weight of the (meth)acrylic monomer (B) is 125 to 300. <8> The photocurable composition according to any one of <1> to <7>, wherein the content of the (meth)acrylic monomer (A) is 300 to 950 parts by mass with respect to 1000 parts by mass of the (meth)acrylic monomer component contained in the photocurable composition. <9> The content of the (meth)acrylic monomer (B) is 50 to 700 parts by mass with respect to 1000 parts by mass of the ( meth)acrylic monomer component contained in the photocurable composition. The photocurable composition according to any one of <1> to <8>. <10> The photocurable composition according to any one of <1> to <9>, wherein the viscosity measured at 25 °C and 50 rpm by an E-type viscometer is 5 mPa·s to 6000 mPa·s. <11> The photocurable composition was irradiated with visible light at a wavelength of 405 nm at a dose of 11 mJ / cm². 2 By irradiating with a 50 μm thick hardened layer A1, and stacking the hardened layer A1 in the thickness direction, a rectangular plate-shaped object A1 with a length of 64 mm, a width of 10 mm, and a thickness of 3.3 mm is formed, and the object A1 is irradiated with ultraviolet light of a wavelength of 365 nm at a dose of 10 J / cm². 2 When a rectangular plate-shaped test specimen A1 with a length of 64 mm, a width of 10 mm, and a thickness of 3.3 mm is prepared by irradiation, the bending strength of the test specimen A1 is 50 MPa or more, the bending modulus of elasticity is 1500 MPa or more, and, The photocurable composition was irradiated with visible light at a wavelength of 405 nm at a dose of 11 mJ / cm². 2 By irradiating with a 50 μm thick hardened layer A2, and stacking the hardened layer A2 in the thickness direction, a rectangular plate-shaped object A2 with a length of 39 mm, a width of 8 mm, and a thickness of 4 mm is formed, and the object A2 is irradiated with ultraviolet light of a wavelength of 365 nm at a dose of 10 J / cm². 2 When a rectangular plate-shaped test specimen A2 with a length of 39 mm, a width of 8 mm, and a thickness of 4 mm is prepared by irradiation, the total work of destruction of test specimen A2 is 500 J / m². 2 That's all. <1> ~ <10> A photocurable composition as described in any one of the following. <12> Used in stereolithography, <1> ~ <11> A photocurable composition as described in any one of the following. <13> Used in the manufacture of oral cavity instruments using stereolithography, <1> ~ <12> A photocurable composition as described in any one of the following. <14> <1> ~ <13> A three-dimensional object comprising a cured product of a photocurable composition described in any one of the above. <15> <14> An instrument to be placed inside the oral cavity, including the three-dimensional object described above. [Effects of the Invention]

[0013] According to one aspect of this disclosure, a photocurable composition capable of producing three-dimensional molded objects that have high toughness even after washing with isopropyl alcohol, as well as a three-dimensional molded object obtained from this photocurable composition, and an instrument to be worn in the oral cavity are provided. [Modes for carrying out the invention]

[0014] In this disclosure, a numerical range represented by "~" means a range that includes the numbers written before and after "~" as the lower and upper limits, respectively. In this disclosure, the amount of each component contained in the composition means the total amount of any multiple substances that constitute each component in the composition, unless otherwise specified. In numerical ranges described in stages within this disclosure, the upper or lower limit of one numerical range may be replaced with the upper or lower limit of another numerical range described in stages. Furthermore, in numerical ranges described within this disclosure, the upper or lower limit of that range may be replaced with the values ​​shown in the examples. In this disclosure, "light" is a concept that includes active energy rays such as ultraviolet light and visible light.

[0015] In this disclosure, "(meth)acrylate" means acrylate or methacrylate, "(meth)acryloyl" means acryloyl or methacryloyl, and "(meth)acrylic" means acrylic or methacrylic.

[0016] [Photocurable composition] The photocurable composition of the present disclosure comprises a (meth)acrylic monomer (A) (hereinafter also referred to as "(meth)acrylic monomer (A)") having two urethane bonds and two (meth)acryloyl groups, each of which is linked to each of the two urethane bonds via a C4-C10 alkylene group to which an oxygen atom or nitrogen atom is bonded; a (meth)acrylic monomer (B) (hereinafter also referred to as "(meth)acrylic monomer (B)") having one (meth)acryloyl group; and a photopolymerization initiator. The photocurable composition disclosed herein makes it possible to produce three-dimensional molded objects that have high toughness even after washing with isopropyl alcohol by combining (meth)acrylic monomer (A) and (meth)acrylic monomer (B).

[0017] The photocurable composition disclosed herein is a composition that hardens upon irradiation with light, and a cured product is obtained by hardening this composition. When producing a cured product using the photocurable composition disclosed herein, stereolithography is preferred as the manufacturing method. Preferably, the photocurable composition of the present disclosure is a photocurable composition for stereolithography, in other words, the cured product produced using the photocurable composition of the present disclosure is preferably a stereolithographic product (i.e., a cured product by stereolithography).

[0018] Stereolithography is a method of obtaining a cured object (i.e., a stereolithographic object) by repeatedly irradiating a photocurable composition with light to form a cured layer, thereby accumulating the cured layer. The stereolithography process may be inkjet-based or tank-based (i.e., stereolithography using a liquid tank).

[0019] In inkjet-based stereolithography, droplets of a photocurable composition are ejected from an inkjet nozzle onto a substrate, and a cured product is obtained by irradiating the droplets attached to the substrate with light. In one example of inkjet-based stereolithography, a head equipped with an inkjet nozzle and a light source is scanned in a plane, a photocurable composition is ejected from the inkjet nozzle onto a substrate, and a cured layer is formed by irradiating the ejected photocurable composition with light. These operations are repeated to sequentially build up the cured layers and obtain a cured product (i.e., a stereolithographic product).

[0020] In tank-type stereolithography, a portion of the photocurable composition (i.e., the uncured photocurable composition in a liquid state; the same applies hereinafter) contained in the tank is cured by light irradiation to form a cured layer. By repeating this operation, the cured layers are stacked to obtain a cured product (i.e., a stereolithographic product). Tank-type stereolithography differs from inkjet-type stereolithography in that it uses a tank. Examples of stereolithography using a liquid bath include DLP (Digital Light Processing) and SLA (Stereolithography). In the DLP method, a planar beam of light is irradiated onto the photocurable composition in the liquid tank. In the SLA method, a laser beam is scanned over the photocurable composition in the liquid tank. From the viewpoint of achieving a more effective effect with the photocurable composition disclosed herein, DLP (Deep Light Processing) type stereolithography is preferred as the tank-type stereolithography.

[0021] One example of DLP-based stereolithography is, for instance, A build table that can move vertically, A tray (i.e., a liquid tank) containing a light-transmitting portion is located below the build table (on the gravity side; the same applies hereafter) and contains a photocurable composition. A light source (e.g., an LED light source) is positioned below the tray to irradiate the photocurable composition inside the tray with planar light through the light-transmitting portion of the tray. A 3D printer equipped with the necessary features (for example, Kulzer's "Cara Print 4.0", Asiga's "Max UV", etc.) is used. In this example, first, a gap of one layer is created between the build table and the tray, and this gap is filled with a photocurable composition. Next, the photocurable composition filling the gap is irradiated from below with planar light through the light-transmitting part of the tray, and the irradiated area is cured to form the first cured layer. Next, the gap between the build table and the tray is widened by the next layer, and the resulting space is filled with a photocurable composition. Next, the photocurable composition filling the space is irradiated with light in the same manner as the first curing to form the second cured layer. By repeating the above operations, cured layers are stacked and a three-dimensional object is manufactured. In this example, the manufactured three-dimensional object may be further cured by irradiating it with light again. For DLP-type stereolithography, you may refer to, for example, the descriptions in Japanese Patent Publication No. 5111880 and Japanese Patent Publication No. 5235056.

[0022] <Application> The uses of the photocurable compositions disclosed herein are not particularly limited. The photocurable composition disclosed herein may be a photocurable composition used in the manufacture of dental products. Dental products manufactured using the photocurable composition have high toughness even after washing with isopropyl alcohol. Dental products include dental prostheses, instruments worn in the oral cavity, dental models, and models for lost-wax casting. Dental prosthetics include inlays, crowns, bridges, temporary crowns, and temporary bridges. Examples of devices fitted into the oral cavity include dentures (e.g., complete dentures, partial dentures, etc.), mouthguards, orthodontic appliances, splints such as occlusal splints and splints for treating temporomandibular joint disorders, impression trays, surgical guides, and the like. Examples of dental models include tooth and jaw models.

[0023] The photocurable composition disclosed herein is preferably a photocurable composition used in stereolithography, more preferably a photocurable composition used in the manufacture of dental products by stereolithography, and even more preferably a photocurable composition used in the manufacture of oral instruments by stereolithography.

[0024] <(meth)acrylmonomer(A)> The photocurable compositions of the present disclosure include a (meth)acrylic monomer (A) having two urethane bonds and two (meth)acryloyl groups, each of which is linked to each of the two urethane bonds via a C4-C10 alkylene group to which an oxygen or nitrogen atom is bonded. (Meth)acrylic monomer (A) may be used alone or in combination of two or more types.

[0025] (Meth)acrylic monomer (A) is a compound having two urethane bonds, and each of the two (meth)acryloyl groups and each of the two urethane bonds is linked via a C4-C10 alkylene group to which an oxygen atom or nitrogen atom is bonded. In (meth)acrylic monomer (A), each of the two (meth)acryloyl groups is bonded to an oxygen atom or nitrogen atom bonded to a C4-C10 alkylene group, preferably to an oxygen atom or nitrogen atom bonded to a C4-C8 alkylene group, and more preferably to an oxygen atom or nitrogen atom bonded to a C4 alkylene group. By using this (meth)acrylic monomer (A), three-dimensional molded objects with excellent flexural modulus, flexural strength, and toughness can be obtained.

[0026] The (meth)acrylic monomer (A) is preferably a compound having two urethane bonds, wherein each of the two (meth)acryloyl groups and each of the two urethane bonds are linked via an alkylene group having 4 to 10 carbon atoms to which an oxygen atom is bonded, and more preferably a compound represented by the following general formula (A-1).

[0027] [ka]

[0028] In formula (A-1), R 1A It is a divalent hydrocarbon group, R 2A and R 3A Each of these is an alkylene group having 4 to 10 carbon atoms, and R 4A and R 5A These are, independently, a methyl group or a hydrogen atom.

[0029] R in general formula (A-1) 1A It is preferably a divalent hydrocarbon group having 5 to 20 carbon atoms, more preferably a divalent chain hydrocarbon group having 5 to 10 carbon atoms, more preferably a divalent hydrocarbon group having 6 to 18 carbon atoms with a cyclic structure, and even more preferably a divalent hydrocarbon group having 8 to 16 carbon atoms with a cyclic structure.

[0030] Examples of divalent chain hydrocarbon groups having 5 to 10 carbon atoms include pentylene, hexylene, heptylene, octylene, nonylene, and desilene groups.

[0031] Examples of cyclic structures include aromatic ring structures and alicyclic structures. Cyclic structures also include combinations of aromatic ring structures with other linking groups (e.g., divalent hydrocarbon groups), such as the bisphenol A structure.

[0032] Examples of aromatic ring structures include benzene rings, naphthalene rings, bisphenol A structures, phenylphenol structures, phenoxybenzyl structures, phenylalkylene structures, and α-hydroxyphenyl structures.

[0033] Examples of alicyclic structures include cyclopropylene, cyclobutylene, cyclopentylene, cyclohexylene, cyclohexenylene, cycloheptylene, cyclooctylene, cyclononylene, cyclodecylene, cycloundecylene, cyclododecylene, cyclotridecylene, cyclotetradecylene, cyclopentadecylene, cyclooctadecylene, cycloicosilene, bicyclohexylene, norbornylene, isobornylene, and adamantylene groups. Of these, norbornylene and isobornylene groups are preferred.

[0034] R in general formula (A-1) 1A It is preferable that the group is represented by any of the following general formulas (a-1) to (a-7), and more preferably by any of the following general formulas (a-1) to (a-4).

[0035] [ka]

[0036] In equations (a-1) to (a-7), * indicates the bonding position.

[0037] R2A and R 3A Each of these is independently an alkylene group having 4 to 10 carbon atoms, preferably an alkylene group having 4 to 8 carbon atoms, and more preferably an alkylene group having 4 carbon atoms. Examples of alkylene groups having 4 to 10 carbon atoms include 1,4-butanediyl group, 1,2-dimethyl-1,2-ethanediyl group, 2-methyl-1,3-propanediyl group, 1,5-pentanediyl group, 1,6-hexanediyl group, 1,7-heptanediyl group, 1,8-octanediyl group, 1,9-nonanediyl group, 1,10-decanediyl group, and 2,4,4-trimethylhexylene group. 2A and R 3A Preferably, both are 1,4-butanediyl groups.

[0038] The molecular weight of (meth)acrylic monomer (A) is preferably 440 to 750, more preferably 440 to 650, even more preferably 450 to 600, and particularly preferably 470 to 550.

[0039] From the viewpoint of obtaining a three-dimensional molded product with excellent flexural modulus, flexural strength, and toughness, the content of (meth)acrylic monomer (A) is preferably 300 to 950 parts by mass, more preferably 350 to 900 parts by mass, and even more preferably 400 to 900 parts by mass, per 1000 parts by mass of (meth)acrylic monomer components contained in the photocurable composition.

[0040] <(meth)acrylmonomer(B)> The photocurable compositions of this disclosure comprise a (meth)acrylic monomer (B) having one (meth)acryloyl group. (Meth)acrylic monomer (B) may be used alone or in combination of two or more types.

[0041] By combining this (meth)acrylic monomer (B), which has one (meth)acryloyl group, with the aforementioned (meth)acrylic monomer (A), it becomes possible to manufacture three-dimensional objects that retain high toughness even after washing with isopropyl alcohol.

[0042] The (meth)acrylic monomer (B) of this disclosure is preferably at least one of the compound represented by the following general formula (B-1) and the compound represented by the following general formula (B-2).

[0043] [ka]

[0044] In formula (B-1), R 1B1 R is a monovalent organic group having one or more selected from the group consisting of an aromatic ring, a hydroxyl group, and a carboxyl group. 2B1 This is a methyl group or a hydrogen atom. R 1B1 The aforementioned monovalent organic group is preferably a monovalent organic group having 2 to 30 carbon atoms, and more preferably a monovalent organic group having 4 to 20 carbon atoms. In formula (B-2), R 1B2 and R 2B2 Each of these is independently a monovalent organic group, and R 1B2 and R 2B2 They may bond to each other to form a ring, R 3B2 This is a methyl group or a hydrogen atom. R 1B2 and R 2B2 The aforementioned monovalent organic group is preferably a monovalent organic group having 2 to 10 carbon atoms, and more preferably a monovalent organic group having 2 to 5 carbon atoms. R 1B2 and R 2B2 When the atoms are bonded to each other to form a ring, the ring may be composed of nitrogen atoms and carbon atoms, or it may be composed of nitrogen atoms, heteroatoms other than nitrogen atoms (e.g., oxygen atoms), and carbon atoms. R 1B2 and R 2B2 When the elements are bonded to each other to form a ring, the ring may be a 4-membered to 8-membered ring, or a 5-membered or 6-membered ring.

[0045] The (meth)acrylic monomer (B) of this disclosure may contain two or more compounds represented by general formula (B-1), or two or more compounds represented by general formula (B-2), or a combination of one or more compounds represented by general formula (B-1) and one or more compounds represented by general formula (B-2).

[0046] R 1B1 It is preferable that the group is a monovalent organic group having an aromatic ring, a monovalent organic group having a hydroxyl group, or a monovalent organic group having a carboxyl group. Monovalent organic groups having both an aromatic ring and a hydroxyl group, and monovalent organic groups having both an aromatic ring and a carboxyl group, are classified as monovalent organic groups having an aromatic ring. R 1B1 The flexibility of the three-dimensional object tends to improve when the group is a monovalent organic group having a hydroxyl group or a monovalent organic group having a carboxyl group. A monovalent organic group having an aromatic ring may also be a monovalent organic group having both an aromatic ring and a hydroxyl group.

[0047] A monovalent organic group having an aromatic ring may have the aromatic ring structure shown below. In the aromatic ring structure shown below, * indicates the bond position.

[0048] [ka]

[0049] The molecular weight of (meth)acrylic monomer (B) is preferably 125 to 300, more preferably 130 to 280, and even more preferably 130 to 270.

[0050] From the viewpoint of obtaining a three-dimensional molded product with excellent flexural modulus, flexural strength, and toughness, the content of (meth)acrylic monomer (B) is preferably 50 to 700 parts by mass, more preferably 100 to 650 parts by mass, and even more preferably 100 to 600 parts by mass, per 1000 parts by mass of (meth)acrylic monomer components contained in the photocurable composition.

[0051] From the viewpoint of obtaining a three-dimensional molded object with excellent flexural modulus, flexural strength, and toughness, the ratio of (meth)acrylic monomer (A) and (meth)acrylic monomer (B) content ((meth)acrylic monomer (A):(meth)acrylic monomer (B)) may be 40:60 to 95:5, or 45:55 to 90:10.

[0052] The photocurable compositions disclosed herein may also contain photopolymerizable components other than (meth)acrylic monomer (A) and (meth)acrylic monomer (B) (hereinafter referred to as "other photopolymerizable components"). Other photopolymerizable components include compounds containing ethylenic double bonds. Compounds containing ethylenic double bonds include (meth)acrylic monomers other than (meth)acrylic monomer (A) and (meth)acrylic monomer (B), styrene, styrene derivatives, (meth)acrylonitrile, and the like. Hereinafter, (meth)acrylic monomer (A), (meth)acrylic monomer (B), and other photopolymerizable components used as needed will also be referred to as photopolymerizable components.

[0053] From the viewpoint of mechanical strength in three-dimensional molded objects, the content of the photopolymerizable component relative to the total amount of the photocurable composition of the present disclosure is preferably 60% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more. The upper limit of the amount of photopolymerizable components relative to the total amount of the photocurable composition disclosed herein is not particularly limited and may be less than 100% by mass, for example, 99.9% by mass or less.

[0054] From the viewpoint of obtaining a three-dimensional molded product with excellent flexural modulus, flexural strength, and toughness, the total content of (meth)acrylic monomer (A) and (meth)acrylic monomer (B) is preferably 50% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more, based on the total mass of the photopolymerizable components. There is no particular upper limit on the total content of (meth)acrylic monomer (A) and (meth)acrylic monomer (B), as long as it is 100% by mass or less relative to the total mass of the photopolymerizable components.

[0055] Other photopolymerizable components, (meth)acrylic monomers, are represented by the general formula (C-1). It may also contain (meth)acrylic monomer (C).

[0056] [ka]

[0057] In formula (C-1), R 1C It is a divalent hydrocarbon group, R 2C and R 3C Each of these is independently an alkylene group having 2 or 3 carbon atoms, and R 4C and R 5C These are, independently, a methyl group or a hydrogen atom. R 1C A preferred configuration is R in the above-mentioned equation (A-1). 1A This is similar to the preferred configuration. R 2C and R 3C These are, independently, alkylene groups having 2 or 3 carbon atoms. Examples of alkylene groups having 2 or 3 carbon atoms include ethylene, propylene, and methylethylene groups. 2C and R 3C Preferably, both are ethylene groups.

[0058] Other photopolymerizable components, such as (meth)acrylic monomers, include (meth)acrylic monomers having two (meth)acryloyl groups and no urethane bond, and (meth)acrylic monomers having three or more (meth)acryloyl groups.

[0059] The content of other photopolymerizable components (preferably (meth)acrylic monomer (C)) is preferably 50% by mass or less, more preferably 20% by mass or less, and even more preferably 10% by mass or less, based on the total mass of the photopolymerizable components. The lower limit of the content of other photopolymerizable components (preferably (meth)acrylic monomer (C)) is not particularly limited, and it is sufficient if it is 0% by mass or more relative to the total mass of the photopolymerizable components.

[0060] <Photopolymerization initiator> The photocurable composition disclosed herein contains a photopolymerization initiator. The photopolymerization initiator is not particularly limited as long as it generates radicals when irradiated with light, but it is preferable that it generates radicals at the wavelength of light used during stereolithography. The wavelength of light used in stereolithography is generally 365nm to 500nm, but in practical terms, it is preferably 365nm to 430nm, and more preferably 365nm to 420nm. Examples of photopolymerization initiators include acylphosphine oxide compounds, alkyl benzoyl formate compounds, alkylphenone compounds, titanocene compounds, oxime ester compounds, benzoin compounds, acetophenone compounds, benzophenone compounds, thioxanthone compounds, α-acyloxime ester compounds, phenylglyoxylate compounds, benzyl compounds, azo compounds, diphenyl sulfide compounds, organic dye compounds, iron-phthalocyanine compounds, benzoin ether compounds, and anthraquinone compounds. The photopolymerization initiator may contain only one type, or it may contain two or more types.

[0061] From the viewpoint of reactivity, acylphosphine oxide compounds and alkylphenone compounds are more preferred as photopolymerization initiators, and it is even more preferable to use one or more acylphosphine oxide compounds as photopolymerization initiators, or to use a combination of one or more acylphosphine oxide compounds and one or more alkylphenone compounds.

[0062] Examples of acylphosphine oxide compounds include 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,6-dimethoxybenzoyldiphenylphosphine oxide, and bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide.

[0063] Examples of alkylphenone compounds include 1-hydroxycyclohexylphenyl ketone.

[0064] The total content of the photopolymerization initiator in the photocurable composition of this disclosure is preferably 0.1% to 10% by mass, more preferably 0.3% to 8% by mass, and even more preferably 0.5% to 5% by mass, based on the total amount of the photocurable composition.

[0065] <Other ingredients> The photocurable compositions disclosed herein may optionally contain one or more other components in addition to those described above. If the photocurable composition contains other components, the total mass of (meth)acrylic monomer (A), (meth)acrylic monomer (B), and photopolymerization initiator is preferably 30% by mass or more, more preferably 50% by mass or more, even more preferably 70% by mass or more, even more preferably 80% by mass or more, and even more preferably 90% by mass or more, based on the total amount of the photocurable composition.

[0066] Other components include, for example, monomers other than (meth)acrylic monomer (A) and (meth)acrylic monomer (B) (for example, the aforementioned (meth)acrylic monomer (C)). When a photocurable composition contains monomers other than (meth)acrylic monomer (A) and (meth)acrylic monomer (B) as other components, the content of the monomers as other components is preferably 50% by mass or less, more preferably 30% by mass or less, even more preferably 20% by mass or less, and particularly preferably 10% by mass or less, based on the total mass of (meth)acrylic monomer (A) and (meth)acrylic monomer (B).

[0067] Other components may include, for example, colorants, coupling agents such as silane coupling agents (e.g., 3-acryloxypropyltrimethoxysilane), rubber agents, ion trapping agents, ion exchange agents, leveling agents, plasticizers, defoaming agents, and thermal polymerization initiators. If the photocurable composition of this disclosure contains a thermal polymerization initiator, it becomes possible to use both photocuring and thermal curing in combination. Examples of thermal polymerization initiators include thermal radical generators and amine compounds.

[0068] Other components include inorganic fillers. However, from the viewpoint of further improving the molding accuracy of the cured product, it is preferable that the photocurable composition of this disclosure does not contain an inorganic filler (for example, silica, barium borosilicate glass, etc.; the same applies hereinafter), or, if it contains an inorganic filler, the content of the inorganic filler relative to the total amount of the photocurable composition is 60% by mass or less (more preferably 40% by mass or less, even more preferably 20% by mass or less, and particularly preferably 10% by mass or less).

[0069] The method for preparing the photocurable composition of the present disclosure is not particularly limited. A method for preparing the photocurable composition of this disclosure includes, for example, a method of mixing (meth)acrylic monomer (A), (meth)acrylic monomer (B), a photopolymerization initiator, and other components as needed. The means for mixing each component are not particularly limited and include, for example, ultrasonic dissolution, a double-arm agitator, a roll kneader, a twin-screw extruder, a ball mill kneader, and a planetary agitator. The photocurable composition of this embodiment may also be prepared by mixing the components, filtering them to remove impurities, and then subjecting them to vacuum degassing.

[0070] <Preferred viscosity of photocurable composition> The photocurable composition disclosed herein preferably has a viscosity (hereinafter also simply referred to as "viscosity") of 5 mPa·s to 6000 mPa·s, as measured by an E-type viscometer at 25°C and 50 rpm. Here, rpm stands for revolutions per minute. When the viscosity is between 5 mPa·s and 6000 mPa·s, the photocurable composition offers excellent handling properties when manufacturing cured products (especially stereolithography products). The viscosity is more preferably 10 mPa·s to 5000 mPa·s, even more preferably 20 mPa·s to 5000 mPa·s, and even more preferably 100 mPa·s to 4500 mPa·s.

[0071] In the photocurable composition disclosed herein, the photocurable composition is irradiated with visible light at a wavelength of 405 nm at a dose of 11 mJ / cm². 2 By irradiating with a 50 μm thick hardened layer A1, and stacking the hardened layer A1 in the thickness direction, a rectangular plate-shaped object A1 with a length of 64 mm, a width of 10 mm, and a thickness of 3.3 mm is formed, and the object A1 is irradiated with ultraviolet light of a wavelength of 365 nm at a dose of 10 J / cm². 2 When a rectangular plate-shaped test specimen A1 with a length of 64 mm, a width of 10 mm, and a thickness of 3.3 mm is produced by irradiation, it is preferable that the bending strength of the test specimen A1 is 50 MPa or more and the bending modulus of elasticity is 1500 MPa or more.

[0072] In the photocurable composition disclosed herein, the photocurable composition is irradiated with visible light at a wavelength of 405 nm at a dose of 11 mJ / cm². 2By irradiating with a 50 μm thick hardened layer A2, and stacking the hardened layer A2 in the thickness direction, a rectangular plate-shaped object A2 with a length of 39 mm, a width of 8 mm, and a thickness of 4 mm is formed, and the object A2 is irradiated with ultraviolet light of a wavelength of 365 nm at a dose of 10 J / cm². 2 When a rectangular plate-shaped test specimen A2 with a length of 39 mm, a width of 8 mm, and a thickness of 4 mm is prepared by irradiation, the total work of destruction of test specimen A2 is 500 J / m². 2 It is preferable that the above conditions are met.

[0073] The upper limit of the bending strength of test specimen A1 is not particularly limited and may be, for example, 90 MPa or less. The upper limit of the flexural modulus of test specimen A1 is not particularly limited and may be, for example, 3000 MPa or less. There is no particular upper limit to the total work of fracture for specimen A2, which is 2000 J / m 2 The following is also acceptable.

[0074] For test specimen A1 that has been cleaned with IPA, the bending strength and bending modulus of test specimen A1 may satisfy the aforementioned numerical conditions. For test specimen A2 that has been cleaned with IPA, the total work of fracture of test specimen A2 may satisfy the aforementioned numerical conditions. An example of a cleaning method using IPA is the method described in the examples below.

[0075] When test specimen A1 obtained from the photocurable composition of this disclosure satisfies the aforementioned conditions for flexural strength and flexural modulus, it tends to yield an oral appliance with excellent mechanical strength. When a test specimen A2 obtained from the photocurable composition of this disclosure satisfies the aforementioned conditions for total work of fracture, it tends to yield an oral appliance with excellent toughness.

[0076] [Three-dimensional object] The three-dimensional objects of this disclosure include cured products of the photocurable compositions of this disclosure. Therefore, the three-dimensional molded object of this disclosure retains high toughness even after cleaning with isopropyl alcohol. The three-dimensional object of this disclosure preferably includes a cured product produced by stereolithography (i.e., a stereolithographic object). The method for manufacturing cured products (e.g., stereolithography products) is as described above.

[0077] [Instruments placed inside the oral cavity] The oral cavity instruments of this disclosure include the three-dimensional objects of this disclosure described above. Therefore, the oral cavity instrument of this disclosure retains high toughness even after cleaning with isopropyl alcohol. Specific examples of devices fitted inside the oral cavity are as described above, including dentures, splints, and the like. [Examples]

[0078] The following are examples of the embodiments of this disclosure, but this disclosure is not limited to the following embodiments.

[0079] [Examples 1-19, Comparative Examples 1-3] <Preparation of photocurable compositions> A photocurable composition was obtained by mixing the components shown in Tables 1 to 4 below.

[0080] <Measurement and Evaluation> The obtained photocurable compositions were used for the following measurements and evaluations. The results are shown in Tables 1 to 4.

[0081] (IPA cleaning method) Using a 3D printer (Kulzer, Cara Print 4.0), the resulting photocurable composition was irradiated with visible light at a wavelength of 405 nm at a dose of 11 mJ / cm². 2 A hardened layer A1 with a thickness of 50 μm was formed by irradiation, and by stacking the hardened layer A1 in the thickness direction, a molded object A1 with dimensions of 64 mm in length, 10 mm in width, and 3.3 mm in thickness was obtained. The obtained molded object A1 was immersed in isopropyl alcohol (IPA) and cleaned for 5 minutes using a 60 W ultrasonic cleaner. After drying the cleaned molded object A1 with an air blower, the molded object A1 was irradiated with ultraviolet light at a wavelength of 365 nm at a dose of 10 J / cm².2 By stereolithography under the specified irradiation conditions, a rectangular plate-shaped test specimen A1 with a length of 64 mm, a width of 10 mm, and a thickness of 3.3 mm was obtained. Similarly, using a 3D printer (Kulzer, Cara Print 4.0), the photocurable composition was irradiated with visible light at a wavelength of 405 nm at a dose of 11 mJ / cm². 2 The object was irradiated with UV light to form a 50 μm thick hardened layer A2, and then fabricated to a size of 39 mm in length, 8 mm in width, and 4 mm in thickness, obtaining the fabricated object A2. The obtained fabricated object A2 was immersed in isopropyl alcohol and cleaned for 5 minutes using a 60 W ultrasonic cleaner. After drying the cleaned fabricated object A2 with air blowing, the fabricated object A2 was irradiated with ultraviolet light at a wavelength of 365 nm at a dose of 10 J / cm². 2 By stereolithography under the specified irradiation conditions, a rectangular plate-shaped test specimen A2 with a length of 39 mm, a width of 8 mm, and a thickness of 4 mm was obtained. Test specimens that were not washed with IPA were irradiated with ultraviolet light at a wavelength of 365 nm without going through the isopropyl alcohol immersion process described above, to obtain test specimens A1 and A2, respectively. The above cleaning method using IPA is just one example, and the cleaning method using IPA is not limited to the method described in the examples. Furthermore, Tables 1 to 4 show a comparison of each of Examples 1 to 3 and Comparative Examples 1 to 3 with and without IPA cleaning (Examples 1B to 3B, Comparative Examples 1B to 3B). For Examples 4-19, only those with IPA cleaning (Examples 4B-19B) are shown.

[0082] (Viscosity of photocurable composition) The viscosity of the photocurable composition was measured using an E-type viscometer under conditions of 25°C and 50 rpm.

[0083] (Bending strength and bending modulus of stereolithography) The obtained test specimen A1 (hereinafter referred to as "test specimen") was stored in a constant temperature water bath at 37±1℃ for 50±2 hours. Subsequently, the test specimens were removed from the constant-temperature water bath, and their bending strength and flexural modulus were measured in accordance with ISO 20795-1:2008. These measurements were performed using a tensile testing apparatus (manufactured by Intesco Corporation) at a tensile speed of 5 ± 1 mm / min.

[0084] (Total work of fracture in fracture toughness tests using bending tests) The obtained test specimen A2 (hereinafter referred to as "test specimen") was notched in accordance with ISO20795-1:2008 and stored in a constant temperature water bath at 37±1℃ for 7 days ±2 hours. Subsequently, the test specimens were removed from the constant temperature water bath, and fracture toughness tests were performed on the removed specimens by bending tests in accordance with ISO20795-1:2008, determining the total work of fracture (J / m). 2 The fracture toughness test by bending (i.e., measurement of total work of fracture) was performed using a tensile testing device (manufactured by Intesco Corporation) at a pressing speed of 1.0 ± 0.2 mm / min.

[0085] [Table 1]

[0086] [Table 2]

[0087] [Table 3]

[0088] [Table 4]

[0089] In Tables 1 to 4, the numbers in the "Composition" column for each example and comparative example represent parts by mass, and a blank space means that the corresponding component is not present.

[0090] <(meth)acrylmonomer(A)> In Tables 1 to 4, the compounds classified as (meth)acrylic monomers (A), which have two urethane bonds and two (meth)acryloyl groups, and in which each of the two (meth)acryloyl groups is linked to each of the two urethane bonds via a C4-C10 alkylene group to which an oxygen or nitrogen atom is bonded, are specifically UDA1 to 4 below.

[0091] UDA1: Compound produced in Manufacturing Example 1 UDA2: Compounds produced in Manufacturing Example 2 UDA3: Compound produced in Manufacturing Example 3 UDA4: Compounds produced in Manufacturing Example 4

[0092] [ka]

[0093] <(meth)acrylmonomer(B)> In Tables 1 to 4, the compounds classified as (meth)acrylic monomers (B) having one (meth)acryloyl group are specifically the following compounds.

[0094] BZA: Benzyl acrylate, manufactured by Osaka Organic Chemical Industry Co., Ltd. PO-A: Phenoxyethyl acrylate, manufactured by Kyoeisha Chemical Co., Ltd. 4-HBA: 4-hydroxybutyl acrylate, manufactured by Osaka Organic Chemical Co., Ltd. POB-A: m-phenoxybenzyl acrylate, manufactured by Kyoeisha Chemical Co., Ltd. A-LEN-10: Ethoxylated-o-phenylphenol acrylate, manufactured by Shin-Nakamura Chemical Industry Co., Ltd. ACMO:4-Acryloylmorpholine, manufactured by KJ Chemicals M5700: 2-Hydroxy-3-Phenoxypropyl Acrylate, manufactured by Toagosei Co., Ltd. HOMS: 2-Methacryloyloxyethyl succinic acid, manufactured by Kyoeisha Chemical Co., Ltd. HEMA: 2-hydroxyethyl acrylate, manufactured by Kyoeisha Chemical Co., Ltd. PO: Phenoxyethyl methacrylate, manufactured by Kyoeisha Chemical Co., Ltd.

[0095] [ka]

[0096] <(meth)acrylmonomer(C)> In Tables 1 to 4, the compounds classified as (meth)acrylic monomer (C) represented by the aforementioned general formula (C-1) are specifically UDA5 to 7 listed below.

[0097] UDA5: Compound produced in manufacturing example 5 UDA6: Compound produced in manufacturing example 6 UDA7: Compound produced in manufacturing example 7

[0098] [ka]

[0099] <Photopolymerization initiator> In Tables 1 to 4, the compounds classified as photopolymerization initiators are specifically the following photopolymerization initiators 1 to 4.

[0100] Omnirad 819: Acylphosphine oxide compound (manufactured by IGM Resins BV) Omnirad 184: Alkylphenone compound (manufactured by IGM Resins BV) Omnirad TPO: Acylphosphine oxide compound (manufactured by IGM Resins BV)

[0101] [ka]

[0102] Manufacturing examples 1 to 7 are described below. The abbreviations used in the following manufacturing examples are explained below. HEA: 2-hydroxyethyl acrylate 2-HPA:2-Hydroxypropyl acrylate 4-HBA:4-hydroxybutyl acrylate DBTDL: Dibutyltin dilaurate MEHQ: 4-Methoxyphenol TMXDI: 1,3-Tetramethylxylylenediisocyanate XDI: m-Xylylene diisocyanate NBDI: norbornane-2,6-diirbis(methylene)diisocyanate H6XDI:1,3-bis(isocyanatomethyl)cyclohexane

[0103] (Manufacturing Example 1: Manufacturing of UDA1) In a 1-liter four-necked flask equipped with a thoroughly dried stirring blade and a thermometer, 288 g (2.00 mol) of 4-HBA, 0.48 g (0.1% by mass of the total mass of 4-HBA and XDI), and 0.24 g (0.05% by mass of the total mass of 4-HBA and XDI) were added and stirred until homogeneous, then the temperature was raised to 60°C. Subsequently, 188 g (1.00 mol) of XDI was added dropwise over 1 hour. As the internal temperature rose due to the heat of reaction during the addition, the amount of addition was controlled to keep the temperature below 80°C. After the entire amount had been added, the reaction temperature was maintained at 80°C and the reaction was carried out for 10 hours. During this time, the progress of the reaction was tracked by HPLC analysis to confirm the endpoint of the reaction. By discharging the product from the reactor, 445 g of urethane acrylate (UDA1) was obtained. The viscosity at 65°C was 430 mPa·s.

[0104] (Manufacturing example 2: Manufacturing of UDA2) In a 1-liter four-necked flask equipped with a thoroughly dried stirring blade and a thermometer, 288 g (2.00 mol) of 4-HBA, 0.48 g (0.1% by mass of the total mass of 4-HBA and TMXDI), and 0.24 g (0.05% by mass of the total mass of 4-HBA and TMXDI) were added and stirred until homogeneous, then the temperature was raised to 60°C. Subsequently, 244 g (1.00 mol) of TMXDI was added dropwise over 1 hour. As the internal temperature rose due to the heat of reaction during the addition, the amount of addition was controlled to keep the temperature below 80°C. After the entire amount had been added, the reaction temperature was maintained at 80°C and the reaction was carried out for 10 hours. During this time, the progress of the reaction was tracked by HPLC analysis to confirm the endpoint of the reaction. By discharging the product from the reactor, 510 g of urethane acrylate (UDA2) was obtained. The viscosity at 65°C was 1600 mPa·s.

[0105] (Manufacturing Example 3: Manufacturing of UDA3) In a 1-liter four-necked flask equipped with a thoroughly dried stirring blade and a thermometer, 390 g (2.70 mol) of 4-HBA, 0.67 g (0.1% by mass of the total mass of 4-HBA and NBDI), and 0.34 g (0.05% by mass of the total mass of 4-HBA and NBDI) were added and stirred until homogeneous, then the temperature was raised to 60°C. Subsequently, 278 g (1.35 mol) of NBDI was added dropwise over 1 hour. As the internal temperature rose due to the heat of reaction during the addition, the amount of addition was controlled to keep the temperature below 80°C. After the entire amount had been added, the reaction temperature was maintained at 80°C and the reaction was carried out for 10 hours. During this time, the progress of the reaction was tracked by HPLC analysis to confirm the endpoint of the reaction. By discharging the product from the reactor, 630 g of urethane acrylate (UDA3) was obtained. The viscosity at 65°C was 360 mPa·s.

[0106] (Manufacturing example 4: Manufacturing of UDA4) In a 1-liter four-necked flask equipped with a thoroughly dried stirring blade and a thermometer, add 288 g (2.00 mol) of 4-HBA, 0.48 g (0.1% by mass relative to the total mass of 4-HBA and H6XDI), and 0.24 g (0.05% by mass relative to the total mass of 4-HBA and H6XDI), stir until homogeneous, and then heat to 60°C. The temperature was raised. Subsequently, 194 g (1.00 mol) of H6XDI was added dropwise over 1 hour. As the internal temperature rose due to the heat of reaction during the addition, the amount added was controlled to keep the temperature below 80°C. After the entire amount had been added, the reaction temperature was maintained at 80°C and the reaction was carried out for 10 hours. During this time, the progress of the reaction was tracked by HPLC analysis to confirm the endpoint of the reaction. By discharging the product from the reactor, 450 g of urethane acrylate (UDA4) was obtained. The viscosity at 65°C was 340 mPa·s.

[0107] (Manufacturing example 5: Manufacturing of UDA5) In a 1-liter four-necked flask equipped with a thoroughly dried stirring blade and a thermometer, 232 g (2.00 mol) of HEA, 0.48 g (0.1% by mass of the total mass of HEA and TMXDI), and 0.24 g (0.05% by mass of the total mass of HEA and TMXDI) were added and stirred until homogeneous, then the temperature was raised to 60°C. Subsequently, 244 g (1.00 mol) of TMXDI was added dropwise over 1 hour. As the internal temperature rose due to the heat of reaction during the addition, the amount of addition was controlled to keep the temperature below 80°C. After the entire amount had been added, the reaction temperature was maintained at 80°C and the reaction was carried out for 10 hours. During this time, the progress of the reaction was tracked by HPLC analysis to confirm the endpoint of the reaction. By discharging the product from the reactor, 455 g of urethane acrylate (UDA5) was obtained. The viscosity at 65°C was 2200 mPa·s.

[0108] (Manufacturing example 6: Manufacturing of UDA6) In a 1-liter four-necked flask equipped with a thoroughly dried stirring blade and a thermometer, 418 g (3.21 mol) of 2HPA, 0.72 g (0.1% by mass of the total mass of 2-HPA and XDI), and 0.36 g (0.05% by mass of the total mass of 2-HPA and XDI) were added and stirred until homogeneous, then the temperature was raised to 60°C. Subsequently, 303 g (1.61 mol) of XDI was added dropwise over 1 hour. As the internal temperature rose due to the heat of reaction during the addition, the amount of addition was controlled to keep the temperature below 80°C. After the entire amount had been added, the reaction temperature was maintained at 80°C and the reaction was carried out for 10 hours. During this time, the progress of the reaction was tracked by HPLC analysis to confirm the endpoint of the reaction. By discharging the product from the reactor, 690 g of urethane acrylate (UDA7) was obtained. The viscosity at 65°C was 570 mPa·s.

[0109] (Manufacturing example 7: Manufacturing of UDA7) In a 1-liter four-necked flask equipped with a thoroughly dried stirring blade and a thermometer, 372 g (3.20 mol) of HEA, 0.70 g (0.1% by mass of the total mass of HEA and NBDI), and 0.35 g (0.05% by mass of the total mass of HEA and NBDI) were added and stirred until homogeneous, then the temperature was raised to 60°C. Subsequently, 330 g (1.60 mol) of NBDI was added dropwise over 1 hour. As the internal temperature rose due to the heat of reaction during the addition, the amount of addition was controlled to keep the temperature below 80°C. After the entire amount had been added, the reaction temperature was maintained at 80°C and the reaction was carried out for 10 hours. During this time, the progress of the reaction was tracked by HPLC analysis to confirm the endpoint of the reaction. By discharging the product from the reactor, 670 g of urethane acrylate (UDA7) was obtained. The viscosity at 65°C was 930 mPa·s.

[0110] As shown in Table 1, no significant change in the total work of fracture in the fracture toughness test by bending test was observed before and after IPA cleaning when using the photocurable compositions of each of Examples 1 to 3. On the other hand, as shown in Table 4, when using the photocurable compositions of Comparative Examples 1 to 3, a significant reduction in the total work of fracture in the fracture toughness test by bending test was observed after IPA cleaning. From these results, it was possible to obtain three-dimensional molded objects with high toughness even after washing with isopropyl alcohol by using the photocurable compositions of each of Examples 1 to 3. In each of Examples 4 to 19, after IPA cleaning, the photocurable compositions from each of Examples 1 to 3 were used. The total work of fracture in the fracture toughness test using a bending test was comparable to that obtained in the previous case. Furthermore, after IPA cleaning, the total work of fracture in the fracture toughness test using a bending test was significantly higher than that obtained when using the photocurable compositions of Comparative Examples 1 to 3. Therefore, by using the photocurable compositions of Examples 4 to 19, it was possible to obtain three-dimensional molded objects with high toughness even after cleaning with isopropyl alcohol.

[0111] The disclosure of Japanese Patent Application No. 2022-054222, filed on 29 March 2022, is incorporated herein by reference in its entirety. All documents, patent applications, and technical standards described herein are incorporated by reference to the same extent as if each individual document, patent application, and technical standard were specifically and individually noted to be incorporated by reference.

Claims

1. (Meth)acrylic monomer (A) having two urethane bonds and two (meth)acryloyl groups, each of the two (meth)acryloyl groups being linked to each of the two urethane bonds via a C4-C10 alkylene group to which an oxygen or nitrogen atom is bonded, A (meth)acrylic monomer (B) having one (meth)acryloyl group, A photopolymerization initiator is included, The (meth)acrylic monomer (B) is at least one of the compound represented by the following general formula (B-1) and the compound represented by the following general formula (B-2), The total content of (meth)acrylic monomer (A) and (meth)acrylic monomer (B) is 80% by mass or more of the total mass of the photopolymerizable components. A photocurable composition in which the (meth)acrylic monomer (A) is a compound represented by the following general formula (A-1). 【Chemistry 1】 (In formula (B-1), R １Ｂ１ R is a monovalent organic group having one or more selected from the group consisting of an aromatic ring, a hydroxyl group, and a carboxyl group. ２Ｂ１ R is a methyl group or a hydrogen atom. In formula (B-2), R １Ｂ２ and R ２Ｂ２ Each of these is independently a monovalent organic group, R １Ｂ２ and R ２Ｂ２ They may bond to each other to form a ring, R ３Ｂ２ (This is a methyl group or a hydrogen atom.) 【Chemistry 2】 (In formula (A-1), R 1A is a group represented by any of the following general formulas (a-1) to (a-7), R 2A and R 3A are each independently an alkylene group having 4 to 10 carbon atoms, and R 4A and R 5A are each independently a methyl group or a hydrogen atom.) 【Transformation 3】 (In equations (a-1) to (a-7), * indicates the bonding position.)

2. The photocurable composition according to claim 1, wherein the molecular weight of the (meth)acrylic monomer (A) is 440 to 650.

3. The photocurable composition according to claim 1, wherein the molecular weight of the (meth)acrylic monomer (B) is 125 to 300.

4. The photocurable composition according to claim 1, wherein the content of the (meth)acrylic monomer (A) is 300 to 950 parts by mass per 1,000 parts by mass of the (meth)acrylic monomer component contained in the photocurable composition.

5. The photocurable composition according to claim 1, wherein the content of the (meth)acrylic monomer (B) is 50 to 700 parts by mass per 1,000 parts by mass of the (meth)acrylic monomer component contained in the photocurable composition.

6. The photocurable composition according to claim 1, wherein the viscosity measured by an E-type viscometer at 25°C and 50 rpm is 5 mPa·s to 6000 mPa·s.

7. The photocurable composition was irradiated with visible light having a wavelength of 405 nm at an irradiation dose of 11 mJ / cm ２ to form a cured layer A1 with a thickness of 50 μm, and the cured layer A1 was laminated in the thickness direction to form a shaped article A1 having a rectangular plate shape with a length of 64 mm, a width of 10 mm, and a thickness of 3.3 mm. When the shaped article A1 was irradiated with ultraviolet light having a wavelength of 365 nm at an irradiation dose of 10 J / cm ２ to produce a test piece A1 having a rectangular plate shape with a length of 64 mm, a width of 10 mm, and a thickness of 3.3 mm, the flexural strength of the test piece A1 was 50 MPa or more, the flexural modulus was 1500 MPa or more, and The photocurable composition was irradiated with visible light at a wavelength of 405 nm at a dose of 11 mJ / cm². ２ By irradiating with a 50 μm thick hardened layer A2, and stacking the hardened layers A2 in the thickness direction, a rectangular plate-shaped object A2 with a length of 39 mm, a width of 8 mm, and a thickness of 4 mm is formed, and the object A2 is irradiated with ultraviolet light of a wavelength of 365 nm at a dose of 10 J / cm². ２ When a rectangular plate-shaped test specimen A2 with a length of 39 mm, a width of 8 mm, and a thickness of 4 mm is produced by irradiation, the total work of destruction of the test specimen A2 is 500 J / m². ２ The above is the photocurable composition according to claim 1.

8. A photocurable composition according to claim 1, used in stereolithography.

9. A (meth)acrylic monomer (A) having two urethane bonds and two (meth)acryloyl groups, each of the two (meth)acryloyl groups being linked to each of the two urethane bonds via a C4-C10 alkylene group to which an oxygen atom or nitrogen atom is bonded, A (meth)acrylic monomer (B) having one (meth)acryloyl group, A photopolymerization initiator is included, The (meth)acrylic monomer (B) is at least one of the compound represented by the following general formula (B-1) and the compound represented by the following general formula (B-2), A photocurable composition used for manufacturing oral appliances by stereolithography, wherein the total content of (meth)acrylic monomer (A) and (meth)acrylic monomer (B) is 80% by mass or more based on the total mass of the photopolymerizable components. 【Chemistry 4】 (In formula (B-1), R 1B1 is a monovalent organic group having one or more selected from the group consisting of an aromatic ring, a hydroxyl group, and a carboxyl group, and R 2B1 is a methyl group or a hydrogen atom. In formula (B-2), R 1B2 and R 2B2 are each independently a monovalent organic group, and R 1B2 and R 2B2 may be bonded to each other to form a ring, and R 3B2 is a methyl group or a hydrogen atom.)

10. A three-dimensional molded object comprising a cured product of the photocurable composition described in claim 1.

11. A (meth)acrylic monomer (A) having two urethane bonds and two (meth)acryloyl groups, each of the two (meth)acryloyl groups being linked to each of the two urethane bonds via a C4-C10 alkylene group to which an oxygen atom or nitrogen atom is bonded, A (meth)acrylic monomer (B) having one (meth)acryloyl group, A photopolymerization initiator is included, The (meth)acrylic monomer (B) is at least one of the compound represented by the following general formula (B-1) and the compound represented by the following general formula (B-2), An oral appliance comprising a three-dimensional molded object containing a cured product of a photocurable composition, wherein the total content of (meth)acrylic monomer (A) and (meth)acrylic monomer (B) is 80% by mass or more relative to the total mass of the photopolymerizable components. 【Transformation 5】 (In formula (B-1), R 1B1 is a monovalent organic group having one or more selected from the group consisting of an aromatic ring, a hydroxyl group, and a carboxyl group, and R 2B1 is a methyl group or a hydrogen atom. In formula (B-2), R 1B2 and R 2B2 are each independently a monovalent organic group, and R 1B2 and R 2B2 may be bonded to each other to form a ring, and R 3B2 is a methyl group or a hydrogen atom.)

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