WO2024204625A1 - Photocurable composition, three-dimensional molded article, dental product, (meth)acrylate, and monomer composition - Google Patents

Abstract

This photocurable composition contains a photopolymerizable component and a photopolymerization initiator. The photopolymerizable component contains (meth)acrylate (A) having one or more urethane bonds and one (meth)acryloyl group, and (meth)acrylate (B) having two or more urethane bonds and two (meth)acryloyl groups.

Description

Photocurable composition, three-dimensional object, dental product, (meth)acrylate and monomer composition

The present invention relates to a photocurable composition, a three-dimensional object, a dental product, a (meth)acrylate, and a monomer composition.

In recent years, technology has been developed to manufacture dental products such as dental prostheses and mouthpieces by stereolithography using a 3D printer (see, for example, Patent Document 1). As a result, a composition containing a (meth)acrylate as a photopolymerizable component has attracted attention as a material that can be used in stereolithography (i.e., is photocurable) and can form a three-dimensional object with physical properties suitable for dental products.

Patent document 1: Patent No. 4160311

The physical properties suitable for dental products include a moderate range of toughness. One method for increasing the toughness of a three-dimensional object made of a composition containing a (meth)acrylate as a photocurable component is to blend a monofunctional (meth)acrylate into the composition. However, the three-dimensional object obtained by this method does not fully achieve the level of toughness desired for dental products, and there is room for further improvement.

In view of the above circumstances, an object of one aspect of the present disclosure is to provide a photocurable composition suitable for obtaining a three-dimensional object having excellent toughness, a three-dimensional object obtained from this photocurable composition, and a dental product including this three-dimensional object.
It is an object of another aspect of the present disclosure to provide novel (meth)acrylates and monomer compositions containing the same.

Specific means for solving the above problems are as follows.
<1> A photopolymerizable component and a photopolymerization initiator are included,
The photocurable composition includes a (meth)acrylate (A) having one or more urethane bonds and one (meth)acryloyl group, and a (meth)acrylate (B) having two or more urethane bonds and two (meth)acryloyl groups.
<2> The photocurable composition according to <1>, wherein the (meth)acrylate (A) is represented by the following general formula (A-1):

In formula (A-1), X ^1A and X ^2A are urethane bonds, R ^1A is a monovalent organic group, R ^2A and R ^3A are each independently a divalent organic group, R ^4A is a methyl group or a hydrogen atom, and n ^A is 0 or 1.
<3> The photocurable composition according to <1> or <2>, wherein the (meth)acrylate (A) is represented by the following general formula (A-1-1) or general formula (A-1-2):

In formula (A-1-1), R ^1A1 is a monovalent organic group, R ^3A1 is a divalent organic group, and R ^4A1 is a methyl group or a hydrogen atom.

In formula (A-1-2), R ^1A2 is a monovalent organic group, R ^2A2 and R ^3A2 are each independently a divalent organic group, R ^4A2 is a methyl group or a hydrogen atom, and n ^A2 is 0 or 1.
<4> The photocurable composition according to any one of <1> to <3>, wherein the (meth)acrylate (A) has a molecular weight of 200 to 800.
<5> The photocurable composition according to any one of <1> to <4>, wherein the (meth)acrylate (B) is represented by the following general formula (B-1):

In formula (B-1), R ^1B is a divalent organic group, R ^2B and R ^3B are each independently a divalent organic group, and R ^4B and R ^5B are each independently a methyl group or a hydrogen atom.
<6> The photocurable composition according to any one of <1> to <5>, wherein the (meth)acrylate (B) has a molecular weight of 400 to 1,000.
<7> The photocurable composition according to any one of <1> to <6>, wherein the content of the (meth)acrylate (A) is 5% by mass to 70% by mass of the total photopolymerizable component.
<8> The photocurable composition according to any one of <1> to <7>, wherein a total content of the (meth)acrylate (A) and the (meth)acrylate (B) is 50 mass% or more of the total photopolymerizable components.
<9> The photocurable composition according to any one of <1> to <8>, having a viscosity of 5 mPa·s to 50,000 mPa·s as measured with an E-type viscometer at 25°C and 5 rpm. <10> The total work of fracture as measured using a test piece having a length of 39 mm, a width of 8 mm and a thickness of 4 mm is 250 J/ ^m2 or more,
The test piece was prepared by irradiating a photocurable composition with visible light having a wavelength of 405 nm at an irradiation dose of 11 mJ/ ^cm2 to form a cured layer having a thickness of 50 μm, and laminating the cured layer in the thickness direction to form a shaped object having a length of 39 mm, a width of 8 mm, and a thickness of 4 mm.
and irradiating the shaped object with ultraviolet light having a wavelength of 365 nm at an irradiation dose of 10 J/ ^cm2 .
<11> The photocurable composition according to any one of <1> to <10>, which is for use in stereolithography.
<12> The photocurable composition according to any one of <1> to <11>, which is used for producing a dental product.
<13> A three-dimensional object which is a cured product of the photocurable composition according to <1>.
<14> A dental product comprising the three-dimensional object according to <13>.
<15> (Meth)acrylate represented by the following general formula (A-1a):

In formula (A-1a), X ^1A and X ^2A are urethane bonds, R ^1A is a monovalent organic group, R ^2A and R ^3A are each independently a divalent organic group, R ^4A is a methyl group or a hydrogen atom, and n ^A is 0 or 1. When n ^A is 0, at least one of R ^1A or R ^3A has a ring structure, and when n ^A is 1, at least one of R ^1A , R ^2A or R ^3A has a ring structure.
<16> The (meth)acrylate according to <15>, which is represented by the following general formula (A-1a-1):

In formula (A-1a-1), R ^1A2 is a monovalent organic group, R ^2A2 and R ^3A2 are each independently a divalent organic group, R ^4A2 is a methyl group or a hydrogen atom, and at least one of R ^1A2 , R ^2A2 and R ^3A2 has a ring structure.
<17> A monomer composition comprising the (meth)acrylate according to <15> or <16>. <18> The monomer composition according to <17>, which is for use in stereolithography.
<19> The monomer composition according to <17> or <18>, which is used for producing a dental product.

According to one aspect of the present disclosure, there is provided a photocurable composition suitable for obtaining a three-dimensional object having excellent toughness, a three-dimensional object obtained from this photocurable composition, and a dental product including the three-dimensional object.
According to another aspect of the present disclosure, there is provided a novel (meth)acrylate and a monomer composition containing the same.

FIG. 2 is a diagram showing the shape of a test piece used in a fastening/detachment test in the examples.

In this specification, a numerical range expressed using "to" means a range that includes the numerical values before and after "to" as the lower and upper limits.
In this specification, "(meth)acrylic" is a concept that includes both acrylic and methacrylic, "(meth)acryloyl" is a concept that includes both acryloyl and methacryloyl, and "(meth)acrylate" is a concept that includes both acrylate and methacrylate.
In this specification, the term "urethane bond" refers to a bond represented by --NHC(.dbd.O)O--.

<Photocurable composition>
The photocurable composition according to the present disclosure includes a photopolymerizable component and a photopolymerization initiator,
The photopolymerizable component includes a (meth)acrylate (A) having one or more urethane bonds and one (meth)acryloyl group, and a (meth)acrylate (B) having two or more urethane bonds and two (meth)acryloyl groups.

As shown in the examples described below, a three-dimensional object formed using the photocurable composition of the present disclosure, which contains, as photopolymerizable components, a (meth)acrylate (A) having one or more urethane bonds and one (meth)acryloyl group, and a (meth)acrylate (B) having two or more urethane bonds and two (meth)acryloyl groups, exhibits superior toughness compared to a three-dimensional object formed using a photocurable composition that does not satisfy the above conditions. Furthermore, while there is a tendency for the bending strength and bending modulus of elasticity of a three-dimensional object obtained using a photocurable composition to decrease as the toughness of the three-dimensional object improves, a three-dimensional object formed using the photocurable composition of the present disclosure exhibits excellent toughness while maintaining good bending strength and bending modulus of elasticity.

((Meth)acrylate (A))
The (meth)acrylate (A) contained in the photocurable composition of the present disclosure is not particularly limited as long as it is a compound having one or more urethane bonds and one (meth)acryloyl group.
The number of urethane bonds contained in the (meth)acrylate (A) is not particularly limited as long as it is 1 or more.
From the viewpoint of improving the toughness of the three-dimensional object, the number of urethane bonds contained in the (meth)acrylate (A) is preferably 1 or more.
From the viewpoint of maintaining good bending strength and bending modulus of elasticity of the three-dimensional object, the number of urethane bonds contained in the (meth)acrylate (A) is preferably 3 or less, and more preferably 2 or less.
From the viewpoint of improving the toughness of the three-dimensional object, the (meth)acrylate (A) preferably contains at least one ring structure. When the (meth)acrylate (A) contains at least one ring structure, the number of ring structures may be selected from 1 to 5, and is preferably 1 to 3. Examples of the ring structure include an alicyclic structure and an aromatic ring structure.

The (meth)acrylate (A) may be a compound represented by the following general formula (A-1):

In formula (A-1), X ^1A and X ^2A are urethane bonds, R ^1A is a monovalent organic group, R ^2A and R ^3A are each independently a divalent organic group, R ^4A is a methyl group or a hydrogen atom, and n ^A is 0 or 1.

The orientation of the urethane bonds represented by ^X1A and ^X2A is not particularly limited. That is, the nitrogen atom constituting the urethane bond represented by ^X1A may be bonded to ^R1A or to ^R2A . The nitrogen atom constituting the urethane bond represented by ^X2A may be bonded to ^R1A or ^R2A , or to ^R3A .

The number of carbon atoms in the monovalent or divalent organic groups represented by R ^1A , R ^2A and R ^3A is not particularly limited.
From the viewpoint of improving the toughness of the three-dimensionally shaped object, it is preferable that the monovalent or divalent organic groups represented by R ^1A , R ^2A and R ^3A each independently have 2 or more carbon atoms.
From the viewpoint of maintaining good bending strength and bending modulus of elasticity of the three-dimensional object, the number of carbon atoms in the monovalent or divalent organic groups represented by R ^1A , R ^2A, and R ^3A is preferably 30 or less, more preferably 20 or less, and even more preferably 15 or less.
When the monovalent or divalent organic groups represented by R ^1A , R ^2A and R ^3A contain two or more hydrocarbon groups, the above number of carbon atoms is the total number of carbon atoms contained in the two or more hydrocarbon groups.
When the monovalent or divalent organic groups represented by R ^1A , R ^2A and R ^3A have a substituent, the above number of carbon atoms includes the number of carbon atoms contained in the substituent.
The monovalent or divalent organic groups represented by R ^1A , R ^2A and R ^3A may or may not contain an unsaturated double bond.

The monovalent or divalent organic groups represented by R ^1A , R ^2A and R ^3A include groups consisting only of hydrocarbons (monovalent or divalent hydrocarbon groups) and groups consisting of hydrocarbons and a linking group.
Examples of the linking group include an ether group (-O-), a sulfonyl group (-SO ₂ -), an ester group (-C(=O)O-), a carbonyl group (-C(=O)-), etc., with the ether group being preferred.
The monovalent or divalent organic groups represented by R ^1A , R ^2A and R ^3A may or may not contain a ring structure.

Examples of the ring structure contained in the monovalent or divalent organic group represented by R ^1A , R ^2A and R ^3A include an aromatic ring structure and an alicyclic structure.
Specific examples of the aromatic ring structure include a benzene ring, a naphthalene ring, and a heterocycle.
Specific examples of the alicyclic structure include a cyclopropane structure, a cyclobutane structure, a cyclopentane structure, a cyclohexane structure, an isobornane structure, a norbornane structure, an adamantane structure, and a decahydronaphthalene structure.
The ring structure may be a structure in which two or more rings are bonded via a single bond or a linking group, such as a biphenyl structure, a 2,2-diphenylpropane (bisphenol A) structure, a diphenylmethane (bisphenol F) structure, a diphenyl ether structure, or a structure in which the benzene ring contained in these structures is replaced with another ring structure.

The ring structure contained in the monovalent or divalent organic group represented by R ^1A , R ^2A , and R ^3A may or may not have a substituent. Specific examples of the substituent include monovalent hydrocarbon groups such as a methyl group, an ethyl group, and an isopropenyl group.

The monovalent or divalent organic group represented by R ^1A , R ^2A , and R ^3A may contain a linear or branched hydrocarbon group and a hydrocarbon group containing a ring structure. For example, a hydrocarbon group containing a ring structure may be bonded directly or via a linker as a branched chain of a linear hydrocarbon group.

When the monovalent or divalent organic groups represented by R ^1A , R ^2A, and R ^3A do not contain a ring structure, the organic group may be linear or branched. Examples of the organic group not containing a ring structure include monovalent or divalent hydrocarbon groups (alkyl groups or alkylene groups).

Specific examples of the monovalent organic group represented by R ^1A include aryl groups such as a phenyl group; arylalkyl groups such as a phenylmethyl (benzyl) group, a diphenylmethyl (benzhydryl) group, a phenylethyl group, a phenylpropyl group, and an isopropenyl-dimethylbenzyl group; aryloxyaryl groups such as a phenoxyphenyl group, and aryloxyarylalkyl groups such as a phenoxybenzyl group, a phenoxyethyl group, and a 2-phenoxy-3-phenoxypropyl group; arylsulfonyl groups such as a phenylsulfonyl group and a toluenesulfonyl group; and cycloalkyl groups such as a cyclohexyl group.

The monovalent organic group represented by R ^1A is preferably a group represented by the following formula: In the formula, * indicates the bonding position.

Specific examples of the divalent organic group represented by R ^2A include an alkylene group, an alkylenearylene group, an alkylenearylenealkylene group, an alkylarylene group, a cycloalkylene group, an alkylenecycloalkylene group, and an alkylenecycloalkylenealkylene group. More specific examples include a hexylene group, a 2,4,4-trimethylhexylene group, a 2,2,4-trimethylhexylene group, a 1,3- or 1,4-phenylene group, a 1,3- or 1,4-phenylenedimethylene group, a 1,3- or 1,4-phenylenediethylene group, a norbornylene group, an isobornylene group, an isophorone group, and a (1,4-cyclohexanediyl)bismethylene group. The divalent organic group represented by R ^2A preferably contains a ring structure, and more preferably has a structure in which an alkylene group, a ring structure, and an alkylene group are bonded in this order.

The divalent organic group represented by R ^2A is preferably a divalent hydrocarbon group represented by the following formulae (a-1) to (a-7), in which * indicates the bonding position.

Specific examples of the divalent organic group represented by ^R3A include alkylene groups such as a dimethylene group, a trimethylene group, and a tetramethylene group; and alkylene groups having a monovalent organic group as a substituent, such as a phenoxyethyl group and a 3-phenoxypropyl group.

At least one of the monovalent or divalent organic groups represented by R ^1A , R ^2A and R ^3A preferably contains a ring structure, and it is preferable that at least the monovalent organic group represented by R ^1A contains a ring structure.
In formula (A-1), n ^A is 0 or 1, and is preferably ¹ in that the three-dimensionally shaped object has an excellent balance of bending strength, bending modulus, and toughness.

The (meth)acrylate (A) may be a compound represented by the following general formula (A-1-1) or general formula (A-1-2).

In formula (A-1-1), R ^1A1 is a monovalent organic group, R ^3A1 is a divalent organic group, and R ^4A1 is a methyl group or a hydrogen atom.

In formula (A-1-2), R ^1A2 is a monovalent organic group, R ^2A2 and R ^3A2 are each independently a divalent organic group, R ^4A2 is a methyl group or a hydrogen atom, and n ^A2 is 0 or 1.

Preferred aspects and specific examples of R ^1A1 and R ^1A2 in formulae (A-1-1) and (A-1-2) are the same as the preferred aspects and specific examples of R ^1A in formula (A-1).
Preferred aspects and specific examples of R ^3A1 and R ^3A2 in formulae (A-1-1) and (A-1-2) are the same as the preferred aspects and specific examples of R ^3A in formula (A-1).
The preferred aspects and specific examples of R ^2A2 in formula (A-1-2) are the same as the preferred aspects and specific examples of R ^2A in formula (A-1).

The molecular weight of the (meth)acrylate (A) is not particularly limited.
From the viewpoint of improving the toughness of the three-dimensional object, the molecular weight of the (meth)acrylate (A) is preferably 200 or more, more preferably 210 or more, and even more preferably 230 or more.
From the viewpoint of maintaining good bending strength and bending modulus of elasticity of the three-dimensional object, the molecular weight of the (meth)acrylate (A) is preferably 800 or less, more preferably 700 or less, and even more preferably 600 or less.

The content of the (meth)acrylate (A) in the photocurable composition is not particularly limited.
From the viewpoint of improving the toughness of a three-dimensional object, the content of the (meth)acrylate (A) in the photocurable composition is preferably 5 mass% or more, more preferably 6 mass% or more, and even more preferably 8 mass% or more, based on the total photopolymerizable composition.

From the viewpoint of maintaining good bending strength and bending modulus of elasticity of the three-dimensional object, the content of (meth)acrylate (A) in the photocurable composition is preferably 70% by mass or less of the total photopolymerizable composition, more preferably 60% by mass or less, and even more preferably 50% by mass or less.

(Method of synthesizing (meth)acrylate (A))
The molecular structure of the (meth)acrylate (A) can be changed by selecting the type of monomer used in the synthesis of the (meth)acrylate (A). Examples of the synthesis method of the (meth)acrylate (A) include the following synthesis method 1, synthesis method 2, and synthesis method 3.

Synthesis method 1: A method of reacting a compound having a monovalent organic group represented by R ^1A1 and one hydroxyl group (hereinafter also referred to as alcohol compound 1) with a compound having a divalent organic group represented by R ^3A1 , one (meth)acryloyl group, and one isocyanate group (hereinafter also referred to as isocyanate compound 1). According to this method, a (meth)acrylate (A) having a structure represented by general formula (A-1-1) can be synthesized.

Synthesis method 2: A method of reacting a compound having a divalent organic group represented by R ^3A2 , one (meth)acryloyl group, and one hydroxyl group (hereinafter also referred to as alcohol compound 2) with a compound having a monovalent organic group represented by R ^1A2 and one isocyanate group (hereinafter also referred to as isocyanate compound 2). According to this method, a (meth)acrylate (A) having a structure in which n is 0 in general formula (A-1-2) can be synthesized.

Synthesis method 3: A method of reacting a compound having a divalent organic group represented by R ^3A2 , one (meth)acryloyl group, and one hydroxyl group (hereinafter also referred to as alcohol compound 3-1), a compound having a monovalent organic group represented by R ^1A2 and one hydroxyl group (hereinafter also referred to as alcohol compound 3-2), and a compound having a divalent organic group represented by R ^2A2 and two isocyanate groups (hereinafter also referred to as isocyanate compound 3). According to this method, a (meth)acrylate (A) having a structure in which n is 1 in general formula (A-1-2) can be synthesized.

The (meth)acrylate (A) obtained by Synthesis Method 3 may be in the form of a mixture of a compound having a monovalent organic group represented by two R ^1A2 , a divalent organic group represented by one R ^2A2 , and two urethane bonds, and a compound having a divalent organic group represented by two R ^3A2 , a divalent organic group represented by one R ^2A2 , two urethane bonds, and two (meth)acryloyl groups.

That is, the photocurable composition may contain a (meth)acrylate (A) having a structure in which n is 1 in general formula (A-1-2), a compound having a monovalent organic group represented by two R ^1A2 , a divalent organic group represented by one R ^2A2 , and two urethane bonds, and a compound having a divalent organic group represented by two R ^3A2 , a divalent organic group represented by one R ^2A2 , two urethane bonds, and two (meth)acryloyl groups.

Specific examples of the alcohol compound 1 and isocyanate compound 1 used in synthesis method 1 and the (meth)acrylate (A) synthesized are shown below.

Specific examples of the alcohol compound 2 and isocyanate compound 2 used in synthesis method 2 and the (meth)acrylate (A) synthesized are shown below.

Specific examples of the alcohol compound 3-1, alcohol compound 3-2, and isocyanate compound 3 used in synthesis method 3, and the (meth)acrylate (A) synthesized are shown below.

((Meth)acrylate (B))
The (meth)acrylate (B) contained in the photocurable composition of the present disclosure is not particularly limited as long as it is a compound having two or more urethane bonds and two (meth)acryloyl groups.
By including the (meth)acrylate (B) in the photocurable composition of the present disclosure, the bending strength and bending modulus of the three-dimensional object can be well maintained. Furthermore, the decrease in toughness after cleaning with a solvent after stereolithography can be suppressed.

The number of urethane bonds contained in the (meth)acrylate (B) is not particularly limited as long as it is 2 or more.
From the viewpoint of maintaining the bending strength and bending modulus of elasticity of the three-dimensional object in a good condition, the number of urethane bonds contained in the (meth)acrylate (B) is preferably 2 to 4, more preferably 2 to 3, and even more preferably 2.
From the viewpoint of preventing a decrease in toughness after cleaning with a solvent after stereolithography while maintaining good bending strength and bending modulus of elasticity of the three-dimensional object, it is preferable that the (meth)acrylate (B) contains at least one ring structure. When the (meth)acrylate (B) contains at least one ring structure, the number of ring structures may be selected from 1 to 5, or may be selected from 1 to 3.

The (meth)acrylate (B) may be a compound represented by the following general formula (B-1):

In formula (B-1), R ^1B is a divalent organic group, R ^2B and R ^3B are each independently a divalent organic group, and R ^4B and R ^5B are each independently a methyl group or a hydrogen atom.

The number of carbon atoms of the divalent organic group represented by R ^1B in formula (B-1) is not particularly limited.
From the viewpoint of improving the bending strength and bending modulus of elasticity of the three-dimensional object while preventing a decrease in toughness after cleaning with a solvent after stereolithography, it is preferable that the total number of carbon atoms in the divalent organic groups represented by R ^1B is independently 5 to 20.
The monovalent organic group represented by R ^1B in formula (B-1) may or may not contain an unsaturated double bond.

The monovalent organic group for R ^1B in formula (B-1) 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 or a divalent hydrocarbon group having 6 to 18 carbon atoms and a cyclic structure, and even more preferably a divalent hydrocarbon group having 8 to 16 carbon atoms and a cyclic structure.

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

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 bisphenol A structures.

Aromatic ring structures include benzene rings, naphthalene rings, bisphenol A structures, phenylphenol structures, phenoxybenzyl structures, phenylalkylene structures, and α-hydroxyphenyl structures.

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

Specific examples and preferred embodiments of the divalent organic group represented by R ^1B in formula (B-1) may be the same as the specific examples and preferred embodiments of the divalent organic group represented by R ^2A and R ^3A in formula (A-1) described above.

In formula (B-1), the divalent organic group represented by R ^1B preferably contains a ring structure, and more preferably has a structure in which an alkylene group, a ring structure, and an alkylene group are bonded in this order.

The divalent organic group represented by R ^1B is preferably a divalent hydrocarbon group represented by the following formulae (a-1) to (a-7), in which * indicates the bonding position.

The divalent organic groups represented by R ^2B and R ^3B in formula (B-1) are each preferably an alkylene group which may have a substituent, preferably an alkylene group having 4 to 10 carbon atoms, more preferably an alkylene group having 4 to 8 carbon atoms, and more preferably an alkylene group having 4 carbon atoms. Examples of the alkylene group having 4 to 10 carbon atoms include a 1,4-butanediyl group, a 1,2-dimethyl-1,2-ethanediyl group, a 2-methyl-1,3-propanediyl group, a 1,5-pentanediyl group, a 1,6-hexanediyl group, a 1,7-heptanediyl group, a 1,8-octanediyl group, a 1,9-nonanediyl group, a 1,10-decanediyl group, and a 2,4,4-trimethylhexylene group. Examples of the substituent include a phenoxy group.

The molecular weight of the (meth)acrylate (B) is not particularly limited.
From the viewpoint of preventing a decrease in toughness after cleaning with a solvent following stereolithography while maintaining good bending strength and bending modulus of elasticity of the three-dimensional object, the molecular weight of the (meth)acrylate (B) is preferably 400 to 1,000, more preferably 420 to 800, and even more preferably 450 to 700 or more.

The content of the (meth)acrylate (B) in the photocurable composition is not particularly limited.
From the viewpoint of preventing a decrease in toughness after cleaning with a solvent after photofabrication while maintaining good bending strength and bending modulus of elasticity of the three-dimensional object, the content of the (meth)acrylate (B) in the photocurable composition is preferably 10% by mass to 95% by mass, more preferably 20% by mass to 90% by mass, and even more preferably 35% by mass to 85% by mass, based on the total amount of the photopolymerizable components.

(Other Photopolymerizable Components)
The photocurable composition may contain only (meth)acrylate (A) and (meth)acrylate (B) as photopolymerizable components, or may further contain a photopolymerizable component other than (meth)acrylate (A) and (meth)acrylate (B). For example, the photocurable composition may contain (meth)acrylate (C) other than (meth)acrylate (A) and (meth)acrylate (B).

Examples of the (meth)acrylate (C) include (meth)acrylate (C-1) having two (meth)acryloyl groups and (meth)acrylate (C-2) having one (meth)acryloyl group. From the viewpoint of the balance between the toughness of the three-dimensional object and the bending strength and bending modulus, (meth)acrylate (C-2) is preferred.

An example of a (meth)acrylate (C-1) having two (meth)acryloyl groups is a (meth)acrylate represented by the following general formula (2).

In the above general formula (2), ^R3 represents a monovalent hydrocarbon group having 1 to 40 carbon atoms or a group in which a portion of the carbon atoms of the hydrocarbon group has been substituted with an oxygen atom or a nitrogen atom, and ^R4 and ^R5 each independently represent a hydrogen atom or a methyl group.
The hydrocarbon group having 1 to 40 carbon atoms represented by ^R3 may or may not contain an unsaturated double bond.

Examples of the monovalent hydrocarbon group having 1 to 40 carbon atoms represented by ^R3 or the group in which a part of the carbon atoms of the hydrocarbon group is substituted with an oxygen atom or a nitrogen atom include an alkylene group, an arylene group, an alkylene oxide group, and combinations thereof having 1 to 40 carbon atoms. Examples of the alkylene group include linear, branched, or cyclic alkyl groups. The number of carbon atoms in the monovalent hydrocarbon group having 1 to 40 carbon atoms represented by ^R3 is preferably 1 to 22, more preferably 1 to 16, and even more preferably 4 to 12.

The monovalent hydrocarbon group having 1 to 40 carbon atoms represented by ^R3 may be unsubstituted or may have a substituent. Examples of the substituent include a halogen atom, an amino group, a hydroxyl group, a carboxy group, and an epoxy group. When the substituent contains a carbon atom, this is not included in the carbon number of the hydrocarbon group.

Specific examples of compounds represented by general formula (2) include propoxylated (2) neopentyl glycol di(meth)acrylate, ethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, glycerin di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, ethoxylated bisphenol A di(meth)acrylate, dimethylol-tricyclodecane di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, dioxane glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, ethoxylated hydrogenated bisphenol A di(meth)acrylate, 2-hydroxy-3-acryloyloxypropyl (meth)acrylate, polyethylene glycol di(meth)acrylate, and polypropylene glycol di(meth)acrylate.

Examples of (meth)acrylates (C-2) having one (meth)acryloyl group include compounds represented by the following general formula (3) and (meth)acryloylmorpholine.

In formula (3), R ¹ represents a monovalent hydrocarbon group having 1 to 40 carbon atoms or a group in which some of the carbon atoms of the hydrocarbon group have been substituted with oxygen atoms or nitrogen atoms, and R ² represents a hydrogen atom or a methyl group.
The monovalent hydrocarbon group having 1 to 40 carbon atoms represented by R ¹ may or may not contain an unsaturated double bond.

Examples of the monovalent hydrocarbon group having 1 to 40 carbon atoms represented by R ¹ or the group in which a part of the carbon atoms of the hydrocarbon group is substituted with an oxygen atom or a nitrogen atom include an alkyl group having 1 to 40 carbon atoms, an aryl group, a group derived from a cyclic ether compound, a group having a urethane bond, and combinations thereof. The alkyl group may be linear, branched, or cyclic. The hydrocarbon group preferably has a cyclic structure. The number of carbon atoms of the monovalent hydrocarbon group having 1 to 40 carbon atoms represented by ^{R 1} is preferably 1 to 22, and more preferably 4 to 12.

The monovalent hydrocarbon group having 1 to 40 carbon atoms represented by ^R1 may be unsubstituted or may have a substituent. Examples of the substituent include a halogen atom, an amino group, a hydroxyl group, a carboxy group, and an epoxy group. When the substituent contains a carbon atom, this is not included in the carbon number of the hydrocarbon group.

Specific examples of compounds represented by general formula (3) include m-phenoxybenzyl acrylate, ethoxylated-o-phenylphenol acrylate, phenoxyethyl (meth)acrylate, phenoxydiethylene glycol (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, isobornyl (meth)acrylate, benzyl (meth)acrylate, cyclohexyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyl (meth)acrylate, 4-tert-butylcyclohexyl (meth)acrylate, tetrahydro Examples include furfuryl (meth)acrylate, (2-methyl-2-ethyl-1,3-dioxolan-4-yl)methyl (meth)acrylate, cyclic trimethylolpropane formal (meth)acrylate, lauryl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-dodecyl-1-hexadecanyl (meth)acrylate, 2-(meth)acryloyloxyethyl-succinic acid, 2-[[(butylamino)carbonyl]oxy]ethyl (meth)acrylate, and 2-(2-ethoxyethoxy)ethyl (meth)acrylate.

When the photocurable composition contains a (meth)acrylate (C), the content of the (meth)acrylate (C) in the photocurable composition is not particularly limited, but is preferably 1% by mass to 40% by mass, more preferably 3% by mass to 30% by mass, and even more preferably 4% by mass to 25% by mass of the entire photocurable composition.

When the photocurable composition contains a photopolymerizable component that does not fall under (meth)acrylate (A) and (meth)acrylate (B), the total proportion of (meth)acrylate (A) and (meth)acrylate (B) is preferably 50% by mass or more of the total photopolymerizable components, more preferably 60% by mass or more, and even more preferably 70% by mass or more.

When the photocurable composition contains a (meth)acrylate component that does not fall under (meth)acrylate (A) or (meth)acrylate (B), the total proportion of (meth)acrylate (A) and (meth)acrylate (B) is preferably 50% by mass or more of the total (meth)acrylate components, more preferably 60% by mass or more, and even more preferably 70% by mass or more.

When the photocurable composition contains (meth)acrylate (C), the total proportion of (meth)acrylate (A), (meth)acrylate (B) and (meth)acrylate (C) is preferably 50% by mass or more of the total photopolymerizable components, more preferably 80% by mass or more, even more preferably 90% by mass or more, and particularly preferably 95% by mass or more.

When the photocurable composition contains (meth)acrylate (C), the total proportion of (meth)acrylate (A), (meth)acrylate (B) and (meth)acrylate (C) is preferably 50% by mass or more of the total (meth)acrylate components, more preferably 80% by mass or more, even more preferably 90% by mass or more, and particularly preferably 95% by mass or more.

(Photopolymerization initiator)
The photocurable composition 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 the photopolymerization initiator generates radicals at the wavelength of light used in stereolithography.
The wavelength of light used in stereolithography is generally 365 nm to 500 nm, preferably 365 nm to 430 nm in practical use, and more preferably 365 nm to 420 nm.

Specific examples of the photopolymerization initiator include alkylphenone compounds, acylphosphine oxide 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.
Among these, from the viewpoint of reactivity and the like, alkylphenone compounds and acylphosphine oxide compounds are preferred.

A specific example of the alkylphenone compound is 1-hydroxy-cyclohexyl-phenyl-ketone (Omnirad 184: manufactured by IGM resins).
Specific examples of the acylphosphine oxide compound include bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (Omnirad 819: manufactured by IGM resins) and 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (Omnirad TPO: manufactured by IGM resins).

The photocurable composition may contain only one type of photopolymerization initiator, or may contain two or more types.

The content of the photopolymerization initiator in the photocurable composition (total content when there are two or more types) is preferably 0.1% by mass to 10% by mass, more preferably 0.2% by mass to 5% by mass, and even more preferably 0.3% by mass to 3% by mass, of the entire photocurable composition.

(Urethane compounds)
The photocurable composition may contain a compound that contains a urethane bond but does not contain a (meth)acryloyl group or a hydroxyl group (hereinafter also referred to as a urethane compound).
The urethane compound includes a compound represented by the following general formula (U-1).

In formula (U-1), R ^1U is a divalent organic group, and R ^2U and R ^3U are each independently a monovalent organic group.

Specific examples and preferred embodiments of the divalent organic group represented by R ^1U are the same as the specific examples and preferred embodiments of the divalent organic group represented by R ^2A in the above formula (A-1).
Specific examples and preferred embodiments of the monovalent organic group represented by R ^2U and R ^3U are the same as the specific examples and preferred embodiments of the monovalent organic group represented by R ^1A in formula (A-1) described above.

When the photocurable composition contains a urethane compound, its content is preferably 0.1% by mass to 20% by mass, more preferably 0.2% by mass to 10% by mass, and even more preferably 1% by mass to 5% by mass, of the entire photocurable composition.

The inclusion of a urethane compound in the photocurable composition can impart plasticity to the three-dimensional object. On the other hand, if the content of the urethane compound is too high, the bending properties and bending modulus of the three-dimensional object may decrease. Therefore, from the viewpoint of suppressing the decrease in bending properties and bending modulus of elasticity, the content of the urethane compound is preferably 20% by mass or less of the entire photocurable composition, more preferably 10% by mass or less, even more preferably 5% by mass or less, and particularly preferably 0% by mass (no urethane compound).

(Other ingredients)
If necessary, the photocurable composition may contain components (other components) other than the photopolymerizable component, the photopolymerization initiator, and the urethane compound.
Specific examples of other components include additives such as coloring materials, coupling agents, rubber agents, ion trapping agents, ion exchange agents, leveling agents, plasticizers, and antifoaming agents, and thermal polymerization initiators.

If the photocurable composition contains other components, the content thereof (the total content if there are two or more types) is preferably 0.1% by mass to 10% by mass, more preferably 0.2% by mass to 5% by mass, and even more preferably 0.3% by mass to 3% by mass of the entire photocurable composition.

When the photocurable composition contains other components, the total mass of the (meth)acrylate (A), the (meth)acrylic monomer (B) and the photopolymerization initiator is preferably 30 mass% or more, more preferably 50 mass% or more, and even more preferably 70 mass% or more, based on the total amount of the photocurable composition.
When the photocurable composition contains a (meth)acrylate (C), the total mass of the (meth)acrylate (A), the (meth)acrylic monomer (B), the (meth)acrylate (C) and the photopolymerization initiator is more preferably 50 mass% or more, even more preferably 70 mass% or more, even more preferably 80 mass% or more, and even more preferably 90 mass% or more, based on the total amount of the photocurable composition.

(Total Destruction Job)
The photocurable composition of the present disclosure preferably has a total work of fracture of 250 J/m2 ^or more, as measured using a test piece made from the photocurable composition and having a length of 39 mm, a width of 8 mm, and a thickness of 4 mm. When the total work of fracture is 250 J/m2 or ^more , a three-dimensional object made from the photocurable composition can be evaluated as exhibiting excellent toughness.

From the viewpoint of ensuring sufficient toughness, the total work of fracture is preferably 300 J/m ² or more, more preferably 400 J/m ² or more, and even more preferably 500 J/m ² or more.
The total work of fracture may be less than or equal to 2000 J/ ^m2 .

The test piece used for measuring the total work of fracture was prepared by irradiating a photocurable composition with visible light having a wavelength of 405 nm at an irradiation dose of 11 mJ/ ^cm2 to form a cured layer having a thickness of 50 μm, which was then laminated in the thickness direction to form a 39 mm long, 8 mm wide and 4 mm thick object.
The object is irradiated with ultraviolet light having a wavelength of 365 nm at an irradiation dose of 10 J/ ^cm2 .

The total work of fracture is measured by a fracture toughness test using a bending test in accordance with ISO 20795-1:2013. Specifically, it is measured using the method described in the Examples.

(viscosity)
The photocurable composition of the present disclosure preferably has a viscosity (hereinafter also simply referred to as "viscosity") measured with an E-type viscometer at 25°C and 5 rpm of 5 mPa·s to 50,000 mPa·s.
Here, rpm means revolutions per minute.
When the viscosity of the photocurable composition is within the above range, the photocurable composition has excellent handleability when a three-dimensional object is produced by stereolithography.

The viscosity of the photocurable composition is more preferably 10 mPa·s to 30,000 mPa·s, even more preferably 20 mPa·s to 25,000 mPa·s, and even more preferably 100 mPa·s to 15,000 mPa·s.

(Uses of the photocurable composition)
The photocurable composition can be suitably used in a method for producing a three-dimensional object by stereolithography.
In this disclosure, "stereolithography" is one type of three-dimensional modeling method using a 3D printer.
The photocurable composition can be suitably used for producing dental products, and preferably can be suitably used for instruments to be worn in the oral cavity, dental models (such as dental surgery models), dental materials (such as dental restorative materials), etc. Examples of instruments to be worn in the oral cavity are described below.

<Three-dimensional objects>
The three-dimensional object of the present disclosure is a three-dimensional object made of the photocurable composition of the present disclosure described above. More specifically, the three-dimensional object of the present disclosure is a cured product obtained by irradiating the photocurable composition with light and curing it.
The method for producing a three-dimensional object from the photocurable composition is not particularly limited, and can be selected from known stereolithography methods.

Representative stereolithography methods include liquid tank type stereolithography methods such as the SLA (Stereo Lithography Apparatus) method and the DLP (Digital Light Processing) method, and inkjet methods.
An example of the SLA method is a method in which a photocurable composition is irradiated with spot-shaped light to form a cured product, and layers of the cured product are laminated to obtain a three-dimensional object.
An example of the DLP method is a method in which a photocurable composition is irradiated with planar light to form a cured product, and layers of the cured product are laminated to obtain a three-dimensional object.
An example of the inkjet method is a method in which droplets of a photocurable composition are continuously discharged from an inkjet nozzle onto a substrate, and the droplets attached to the substrate are irradiated with light to obtain a three-dimensional object.

When irradiating light to completely harden a three-dimensional object obtained by photopolymerization, the method is not particularly limited. For example, the three-dimensional object may be completely hardened by irradiating light using an LED lamp or the like.

The physical properties of the three-dimensional object are not particularly limited and can be selected according to the application.
For example, the bending strength of the three-dimensional object is preferably 50 MPa or more, more preferably 60 MPa or more, and even more preferably 65 MPa or more.
For example, the flexural modulus of elasticity of the three-dimensional object is preferably 1500 MPa or more, more preferably 1700 MPa or more, and further preferably 2000 MPa or more.
The bending strength and bending modulus of elasticity of the three-dimensional object are measured by the methods described in the Examples section below.

<Dental products>
The dental product of the present disclosure includes the three-dimensional object of the present disclosure.
The type of dental product is not particularly limited. Specific examples include instruments to be attached to the oral cavity, dental models (such as models for dental surgery), and dental materials (such as dental restorative materials).
Specific examples of devices that are worn in the oral cavity include dentures, lining materials, mouthpieces, mouthguards, splints, etc.

The dental product of the present disclosure includes the three-dimensionally shaped object of the present disclosure, which has excellent toughness, and therefore provides an excellent fit in the user's oral cavity and excellent durability, therapeutic effect, protection from impact, and the like according to the intended use of the dental product.

<(Meth)acrylate>
The (meth)acrylate of the present disclosure is a (meth)acrylate represented by the following general formula (A-1a).

In formula (A-1a), X ^1A and X ^2A are urethane bonds, R ^1A is a monovalent organic group, R ^2A and R ^3A are each independently a divalent organic group, R ^4A is a methyl group or a hydrogen atom, and n ^A is 0 or 1. When n ^A is 0, at least one of R ^1A or R ^3A has a ring structure, and when n ^A is 1, at least one of R ^1A , R ^2A or R ^3A has a ring structure.

The (meth)acrylate having the above structure is useful, for example, as a photopolymerizable component contained in a material for stereolithography.
As shown in the examples described later, a three-dimensional object obtained using a composition containing a (meth)acrylate having the above structure exhibits superior toughness compared to a three-dimensional object obtained using a composition not containing a (meth)acrylate having the above structure.

Specific examples and preferred embodiments of R ^1A , R ^2A and R ^3A in formula (A-1a) are the same as the specific examples and preferred embodiments of R ^1A , R ^2A and R ^3A in formula (A-1).

The (meth)acrylate of the present disclosure may be a compound represented by the general formula (A-1a-1).

In formula (A-1a-1), R ^1A2 is a monovalent organic group, R ^2A2 and R ^3A2 are each independently a divalent organic group, R ^4A2 is a methyl group or a hydrogen atom, and at least one of R ^1A2 , R ^2A2 and R ^3A2 has a ring structure.

Specific examples and preferred embodiments of R ^1A2 , R ^2A2 and R ^3A2 in formula (A-1a-1) are the same as the specific examples and preferred embodiments of R ^1A , R ^2A and R ^3A in formula (A-1).

<Monomer Composition>
The monomer composition of the present disclosure includes the (meth)acrylate of the present disclosure described above.
The monomer composition can be suitably used in a method for producing a three-dimensional object by stereolithography.
The monomer composition is suitable for use in the manufacture of dental products.

In the monomer composition of the present disclosure, the content of the (meth)acrylate of the present disclosure described above is preferably 70% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more, relative to the total monomer composition, and may be 99% by mass or less.

The present invention will be specifically explained below based on examples, but the present invention is not limited to these examples.

<Preparation of Photocurable Composition>
Photocurable compositions of Comparative Examples 1 to 3 and Examples 1 to 42 were prepared using the materials shown in Tables 2 to 5. Details of the materials shown in Tables 2 to 5 are as follows.

UA-A1: (meth)acrylate with the following structure, molecular weight: 249.27

UA-A2: (meth)acrylate with the following structure, molecular weight: 341.36

UA-A3: (Meth)acrylate with the following structure, molecular weight: 279.29

UA-A4: (Meth)acrylate with the following structure, molecular weight: 325.36

UA-4B1: (meth)acrylate with the following structure, molecular weight: 263.29

UA-4B2: (meth)acrylate with the following structure, molecular weight: 269.34

UA-4B3: (meth)acrylate with the following structure, molecular weight: 277.32

UA-4B4: (Meth)acrylate with the following structure, molecular weight: 341.38

UA-4B5: (meth)acrylate with the following structure, molecular weight: 345.44

UA-P1: (meth)acrylate with the following structure, molecular weight: 341.36

UA-P2: (meth)acrylate with the following structure, molecular weight: 347.41

UA-P3: (meth)acrylate with the following structure, molecular weight: 355.39

UA-P4: (meth)acrylate with the following structure, molecular weight: 419.45

UA-2: (meth)acrylate with the following structure, molecular weight: 496.60

UA-3: (Meth)acrylate with the following structure, molecular weight: 458.56

UA-4: (Meth)acrylate with the following structure, molecular weight: 588.70

UA-5: (Meth)acrylate with the following structure, molecular weight: 526.63

V216: (Meth)acrylate with the following structure (manufactured by Osaka Organic Chemical Industry Co., Ltd.), molecular weight: 215.25

UDA1: (meth)acrylate with the following structure, molecular weight: 476.53

UDA2: (Meth)acrylate with the following structure, molecular weight: 532.63

UDA3: (Meth)acrylate with the following structure, molecular weight: 494.59

UDA4: (Meth)acrylate with the following structure, molecular weight: 632.67

POB-A: (meth)acrylate with the following structure (manufactured by Kyoeisha Chemical), molecular weight: 254.28

A-LEN-10: (meth)acrylate with the following structure (manufactured by Shin-Nakamura Chemical Co., Ltd.), molecular weight: 268.31

ACMO: (meth)acrylate with the following structure (acryloylmorpholine, manufactured by KJ Chemicals), molecular weight: 141.17

DA-2: Urethane compound with the following structure, molecular weight: 460.57

DA-3: Urethane compound with the following structure, molecular weight: 422.53

DA-4: Urethane compound with the following structure, molecular weight: 644.77

DA-5: Urethane compound with the following structure, molecular weight: 520.63

Omnirad 819: Photopolymerization initiator with the following structure

Omnirad 184: Photopolymerization initiator with the following structure

OmniradTPO: Photopolymerization initiator with the following structure

The following describes examples of the preparation of compounds used in the preparation of photocurable compositions. The abbreviations in the examples are as follows.
4HBA: 4-hydroxybutyl acrylate DBTDL: dibutyltin dilaurate MEHQ: 4-methoxyphenol TMXDI: 1,3-tetramethylxylylene diisocyanate XDI: m-xylylene diisocyanate NBDI: norbornene diisocyanate PHI: phenyl isocyanate CHI: cyclohexyl isocyanate TOI: tolyl isocyanate TSI: toluenesulfonyl isocyanate IPDBI: isopropenyl-dimethylbenzyl isocyanate AOI: 2-isocyanatoethyl acrylate HPPA: 2-hydroxy-3-phenoxypropyl acrylate BZ-OH: benzyl alcohol POB-OH: m-phenoxybenzyl alcohol PH-OH: 2-phenoxyethanol BHR-OH: benzhydrol

(Production Example of UA-A1)
In a 1-liter four-neck flask equipped with a thoroughly dried stirring blade and a thermometer, 216 g (2.00 mol) of BZ-OH as an alcohol compound, 0.53 g (0.1 wt % relative to the total weight of BZ-OH and AOI), and 0.27 g (0.05 wt % relative to the total weight of BZ-OH and AOI) were added, stirred until homogenized, and then heated to 60°C. Subsequently, 314 g (2.00 mol) of AOI as an isocyanate compound was added dropwise over 1 hour. During the dropwise addition, the internal temperature rose due to reaction heat, so the amount of dropwise addition was controlled so that the temperature was 80°C or less. After the entire amount was added dropwise, the reaction temperature was kept at 80°C and the reaction was carried out for 10 hours. At this time, the progress of the reaction was tracked by HPLC analysis to confirm the end point of the reaction. By discharging the product from the reactor, 530 g of urethane acrylate (UA-A1) was obtained. The viscosity at 25° C. was 80 mPa·s.

(UA-A2, UA-A2, UA-A3, UA-A4, UA-4B1, UA-4B2, UA-4B3, UA-4B4, UA-4B5, UA-P1, UA-P2, UA-P3 and UA - Manufacturing example of P4)
The same procedure as in Production Example UA-A1 was repeated except that the types of isocyanate compound and alcohol compound in Production Example UA-A1 were changed to those shown in Table 1 and the amounts of each component were changed to those shown in Table 1. The above (meth)acrylate was produced in the same manner as in Example 1. The yield of the produced (meth)acrylate and its viscosity at 65° C. or 25° C. are shown in Table 1.

(Production Example of UDA2/UA-2/DA-2 Mixture)
In a 1-liter four-neck flask equipped with a thoroughly dried stirring blade and a thermometer, 231 g (1.60 mol) of 4HBA, 43 g (0.40 mol) of BZ-OH, 0.52 g (0.1 wt % relative to the total weight of 4HBA, BZ-OH and TMXDI), and 0.26 g (0.05 wt % relative to the total weight of 4HBA, BZ-OH and TMXDI) were added, stirred until homogeneous, and then heated to 60°C. Subsequently, 244 g (1.00 mol) of TMXDI was added dropwise over 1 hour. During the dropwise addition, the internal temperature rose due to the heat of reaction, so the amount of dropwise addition was controlled so that it was 80°C or less. After the entire amount was added dropwise, the reaction temperature was kept at 80°C and the reaction was carried out for 10 hours. At this time, the progress of the reaction was tracked by HPLC analysis to confirm the end point of the reaction. The product was discharged from the reactor to obtain 490 g of urethane acrylate (UDA2/UA-2/DA-2 mixture). The viscosity at 65° C. was 1300 mPa·s. The composition ratio of UDA2/UA-2/DA-2 was 65.78 wt %/30.67 wt %/3.55 wt %.

(Production Example of UDA3/UA-3/DA-3 Mixture)
In a 1-liter four-neck flask equipped with a thoroughly dried stirring blade and a thermometer, 231 g (1.60 mol) of 4HBA, 43 g (0.40 mol) of BZ-OH, 0.48 g of DBTDL (0.1% by weight relative to the total weight of 4HBA, BZ-OH and NBDI), and 0.24 g of MEHQ (0.05% by weight relative to the total weight of 4HBA, BZ-OH and NBDI) were added, stirred until homogeneous, and then heated to 60°C. Subsequently, 206 g (1.00 mol) of NBDI was added dropwise over 1 hour. During the dropwise addition, the internal temperature rose due to the reaction heat, so the amount of dropwise addition was controlled so that it was 80°C or less. After the entire amount was added dropwise, the reaction temperature was kept at 80°C and the reaction was carried out for 10 hours. At this time, the progress of the reaction was tracked by HPLC analysis to confirm the end point of the reaction. The product was discharged from the reactor to obtain 450 g of urethane acrylate (UDA3/UA-3/DA-3 mixture). The viscosity at 65° C. was 400 mPa·s. The composition ratio of UDA3/UA-3/DA-3 was 65.92 wt %/30.56 wt %/3.52 wt %.

(Production Example of UDA2/UA-4/DA-4 Mixture)
In a 1-liter four-neck flask equipped with a thoroughly dried stirring blade and a thermometer, 231 g (1.60 mol) of 4HBA, 80 g (0.40 mol) of POB-OH, 0.56 g of DBTDL (0.1% by weight based on the total weight of 4HBA, POB-OH and TMXDI), and 0.28 g of MEHQ (0.05% by weight based on the total weight of 4HBA, POB-OH and TMXDI) were added, stirred until homogenous, and then heated to 60°C. Subsequently, 244 g (1.00 mol) of TMXDI was added dropwise over 1 hour. During the dropwise addition, the internal temperature rose due to the heat of reaction, so the amount of dropwise addition was controlled so that it was 80°C or less. After the entire amount was added dropwise, the reaction temperature was kept at 80°C and the reaction was carried out for 10 hours. At this time, the progress of the reaction was tracked by HPLC analysis to confirm the end point of the reaction. The product was discharged from the reactor to obtain 520 g of urethane acrylate (UDA2/UA-4/DA-4 mixture). The viscosity at 65° C. was 2800 mPa·s. The composition ratio of UDA2/UA-4/DA-4 was 61.41 wt %/33.94 wt %/4.65 wt %.

(Production Example of UDA2/UA-5/DA-5 Mixture)
In a 1-liter four-neck flask equipped with a thoroughly dried stirring blade and a thermometer, 231 g (1.60 mol) of 4HBA, 55 g (0.40 mol) of PH-OH, 0.53 g (0.1 wt % relative to the total weight of 4HBA, PH-OH and TMXDI), and 0.27 g (0.05 wt % relative to the total weight of 4HBA, PH-OH and TMXDI) were added, stirred until homogenous, and then heated to 60°C. Subsequently, 244 g (1.00 mol) of TMXDI was added dropwise over 1 hour. During the dropwise addition, the internal temperature rose due to the reaction heat, so the amount of dropwise addition was controlled so that it was 80°C or less. After the entire amount was added dropwise, the reaction temperature was kept at 80°C and the reaction was carried out for 10 hours. At this time, the progress of the reaction was tracked by HPLC analysis to confirm the end point of the reaction. The product was discharged from the reactor to obtain 500 g of urethane acrylate (UDA2/UA-5/DA-5 mixture). The viscosity at 65° C. was 2400 mPa·s. The composition ratio of UDA2/UA-5/DA-5 was 64.29 wt %/31.78 wt %/3.93 wt %.

(Production Example of UDA1)
In a 1-liter 4-neck flask equipped with a thoroughly dried stirring blade and a thermometer, 288 g (2.00 mol) of 4HBA, 0.48 g (0.1 wt % relative to the total weight of 4HBA and XDI), and 0.24 g (0.05 wt % relative to the total weight of 4HBA and XDI) were added, stirred until homogeneous, and then heated to 60°C. Subsequently, 188 g (1.00 mol) of XDI was added dropwise over 1 hour. During the dropwise addition, the internal temperature rose due to the reaction heat, so the amount of dropwise addition was controlled so that it was 80°C or less. After the entire amount was added dropwise, the reaction temperature was kept at 80°C and the reaction was carried out for 10 hours. At this time, the progress of the reaction was tracked by HPLC analysis to confirm the end point 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.

(Production Example of UDA2)
In a 1-liter 4-neck flask equipped with a thoroughly dried stirring blade and a thermometer, 288 g (2.00 mol) of 4HBA, 0.53 g (0.1 wt % relative to the total weight of 4HBA and TMXDI), and 0.27 g (0.05 wt % relative to the total weight of 4HBA and TMXDI) were added, stirred until homogeneous, and then heated to 60°C. Subsequently, 244 g (1.00 mol) of TMXDI was added dropwise over 1 hour. During the dropwise addition, the internal temperature rose due to the reaction heat, so the amount of dropwise addition was controlled so that it was 80°C or less. After the entire amount was added dropwise, the reaction temperature was kept at 80°C and the reaction was carried out for 10 hours. At this time, the progress of the reaction was tracked by HPLC analysis to confirm the end point 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.

(Production Example of UDA3)
In a 1-liter 4-neck flask equipped with a thoroughly dried stirring blade and a thermometer, 390 g (2.70 mol) of 4HBA, 0.67 g (0.1 wt % relative to the total weight of 4HBA and NBDI), and 0.34 g (0.05 wt % relative to the total weight of 4HBA and NBDI) were added, stirred until homogeneous, and then heated to 60°C. Then, 278 g (1.35 mol) of NBDI was added dropwise over 1 hour. During the dropwise addition, the internal temperature rose due to the reaction heat, so the amount of dropwise addition was controlled so that it was 80°C or less. After the entire amount was added dropwise, the reaction temperature was kept at 80°C and the reaction was carried out for 10 hours. At this time, the progress of the reaction was tracked by HPLC analysis to confirm the end point 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.

(Production Example of UDA4)
In a 1-liter 4-neck flask equipped with a thoroughly dried stirring blade and a thermometer, 444 g (2.00 mol) of M5700, 0.63 g of DBTDL (0.1 wt % relative to the total weight of M5700 and XDI), and 0.32 g of MEHQ (0.05 wt % relative to the total weight of M5700 and XDI) were added, stirred until homogeneous, and then heated to 60 ° C. Then, 188 g (1.00 mol) of XDI was added dropwise over 1 hour. During the dropwise addition, the internal temperature rose due to the reaction heat, so the amount of dropwise addition was controlled so that it was 80 ° C. or less. After the entire amount was added dropwise, the reaction temperature was kept at 80 ° C. and the reaction was carried out for 10 hours. At this time, the progress of the reaction was tracked by HPLC analysis to confirm the end point of the reaction. By discharging the product from the reactor, 600 g of urethane acrylate (UDA4) was obtained. The viscosity at 65° C. was 6,210 mPa·s.

<Measurement and Evaluation>
The photocurable compositions thus obtained were subjected to the following measurements and evaluations. The results are shown in Tables 2 to 5.

(Preparation of test specimens)
The obtained photocurable composition was shaped into a size of 64 mm x 10 mm x 3.3 mm using a 3D printer (Kulzer, Cara Print 4.0) to obtain a molded object P2 (irradiation conditions: wavelength 405 nm, irradiation amount 11 mJ/cm ² , DLP method). The obtained molded object P2 was immersed in isopropanol and washed for 5 minutes using an ultrasonic cleaner with an output of 60 W. After drying the washed molded object P2 with an air blower, the molded object P2 was irradiated with ultraviolet light having a wavelength of 365 nm at an irradiation amount of 10 J/cm ² to be fully cured. Through the above steps, a rectangular plate-shaped test piece P2 having a length of 64 mm, a width of 10 mm, and a thickness of 3.3 mm was obtained.
Similarly, the obtained photocurable composition was shaped into a size of 39 mm x 8 mm x 4 mm using a 3D printer (Kulzer, Cara Print 4.0) to obtain a molded object P1 (irradiation conditions: wavelength 405 nm, irradiation amount 11 mJ/cm ² , DLP method). The obtained molded object P1 was immersed in isopropanol and washed for 5 minutes using an ultrasonic cleaner with an output of 60 W. After drying the washed molded object P1 with an air blower, the molded object P1 was irradiated with ultraviolet light having a wavelength of 365 nm at an irradiation amount of 10 J/cm ² to be fully cured. Through the above steps, a rectangular plate-shaped test piece P1 with a length of 39 mm, a width of 8 mm, and a thickness of 4 mm was obtained.

(Viscosity of Photocurable Composition)
The viscosity of the photocurable composition was measured using an E-type viscometer at 25° C. and 5 rpm.

(Bending strength and bending modulus of elasticity of stereolithography)
Test piece P2 (hereinafter referred to as "test piece") was stored in a thermostatic water bath at 37±1° C. for 50±2 hours. Thereafter, the test piece was removed from the thermostatic water bath, and the flexural strength and flexural modulus of the removed test piece were measured in accordance with ISO20795-1:2013. These measurements were performed using a tensile tester (manufactured by Intesco Corporation) at a tensile speed of 5±1 mm/min.
A bending strength of 65 MPa or more was evaluated as "AA", a bending strength of 50 MPa or more but less than 65 MPa was evaluated as "A", and a bending strength of less than 50 MPa was evaluated as "B".
The flexural modulus was evaluated as "AA" when it was 2000 MPa or more, "A" when it was 1500 MPa or more and less than 2000 MPa, and "B" when it was less than 1500 MPa.

(Total work of fracture in fracture toughness test by bending test)
A notch was applied to the test piece P1 (hereinafter referred to as the "test piece") in accordance with ISO 20795-1: 2013. Thereafter, the test piece was stored in a constant temperature water bath at 37±1° C. for 7 days±2 hours.
Thereafter, the test piece was removed from the thermostatic water bath, and a fracture toughness test was performed by bending test in accordance with ISO 20795-1: 2013 to measure the total work of fracture (J/m ² ). The fracture toughness test by bending test (i.e., measurement of the total work of fracture) was performed using a tensile tester (manufactured by Intesco Corporation) at a pressing speed of 1.0±0.2 mm/min.
The total work of fracture (J/ ^m2 ) obtained was rated as "AA" if it was 1000 or more, "A" if it was 500 or more but less than 1000, "B" if it was 400 or more but less than 500, "C" if it was 250 or more but less than 400, "D" if it was 150 or more but less than 250, and "E" if it was less than 150.

(Attachment and detachment test of three-dimensional objects)
The photocurable composition was used in a 3D printer (Kulzer, Cara Print 4.0) to obtain a molded object having the shape shown in Fig. 1 (irradiation conditions: wavelength 405 nm, irradiation dose 11 mJ/ ^cm2 , DLP method). The obtained molded object was irradiated with ultraviolet light having a wavelength of 365 nm at 10 J/ ^cm2 for full curing, and a test piece for the attachment/detachment test was obtained.

FIG. 1 is a plan view of a test piece 10 used in a mounting/dismounting test and a metal member 20 arranged on a support 30. As shown in FIG.
The test piece 10 has a main body 10A for gripping a metal member and a handle 10B for moving the test piece in the direction of the arrow. The depth of the test piece 10 is 10 mm.
The metal member 20 is formed by cutting a cylinder made of SUS304 and having a diameter of 10 mm, and has a shape such that the cut portion is in contact with the support body 30. The depth of the metal member 20 is 10 mm.
In the attachment/detachment test, the test piece 10 was started from a state where it gripped the metal member 20, and was moved back and forth 10,000 times over a distance of 10 mm along the direction of the arrow. The test piece 10 was moved using a tensile testing device (manufactured by Intesco Corporation) at a moving speed of 120.0±2.0 mm/min.
After 10,000 reciprocating movements, the test piece 10 was observed. Evaluation was performed according to the following criteria: if there was no change in the shape of the test piece and no cracks, it was marked as "○", if there was no crack but there was a change in the shape of the test piece, it was marked as "△", and if there was a crack, it was marked as "×".

 
 

 
 

 
 

As shown in Tables 2 to 5, in the examples in which the photocurable resin contains (meth)acrylate (A) having one or more urethane bonds and one (meth)acryloyl group, and (meth)acrylate (B) having two or more urethane bonds and two (meth)acryloyl groups, the three-dimensional object exhibited superior toughness and good attachment/detachment evaluation compared to the comparative examples in which the photocurable resin contains (meth)acrylate (B) but not (meth)acrylate (A).

The disclosure of Japanese Patent Application No. 2023-059315 is incorporated herein by reference in its entirety.
All publications, patent applications, and standards mentioned in this specification are incorporated by reference into this specification to the same extent as if each individual publication, patent application, and standard was specifically and individually indicated to be incorporated by reference.

Claims (19)

Contains a photopolymerizable component and a photopolymerization initiator,
The photocurable composition includes a (meth)acrylate (A) having one or more urethane bonds and one (meth)acryloyl group, and a (meth)acrylate (B) having two or more urethane bonds and two (meth)acryloyl groups. The photocurable composition according to claim 1, wherein the (meth)acrylate (A) is represented by the following general formula (A-1):

In formula (A-1), X ^1A and X ^2A are urethane bonds, R ^1A is a monovalent organic group, R ^2A and R ^3A are each independently a divalent organic group, R ^4A is a methyl group or a hydrogen atom, and n ^A is 0 or 1. The photocurable composition according to claim 1, wherein the (meth)acrylate (A) is represented by the following general formula (A-1-1) or general formula (A-1-2):

In formula (A-1-1), R ^1A1 is a monovalent organic group, R ^3A1 is a divalent organic group, and R ^4A1 is a methyl group or a hydrogen atom.

In formula (A-1-2), R ^1A2 is a monovalent organic group, R ^2A2 and R ^3A2 are each independently a divalent organic group, R ^4A2 is a methyl group or a hydrogen atom, and n ^A2 is 0 or 1. The photocurable composition according to claim 1, wherein the molecular weight of the (meth)acrylate (A) is 200 to 800. The photocurable composition according to claim 1, wherein the (meth)acrylate (B) is represented by the following general formula (B-1):

In formula (B-1), R ^1B is a divalent organic group, R ^2B and R ^3B are each independently a divalent organic group, and R ^4B and R ^5B are each independently a methyl group or a hydrogen atom. The photocurable composition according to claim 1, wherein the molecular weight of the (meth)acrylate (B) is 400 to 1000. The photocurable composition according to claim 1, wherein the content of the (meth)acrylate (A) is 5% by mass to 70% by mass of the total photopolymerizable components. The photocurable composition according to claim 1, wherein the total content of the (meth)acrylate (A) and the (meth)acrylate (B) is 50% by mass or more of the total photopolymerizable components. The photocurable composition according to claim 1, whose viscosity measured at 25°C and 5 rpm using an E-type viscometer is 5 mPa·s to 50,000 mPa·s. The total work of fracture measured using a test specimen having a length of 39 mm, a width of 8 mm and a thickness of 4 mm is 250 J/ ^m2 or more;
The test piece was prepared by irradiating a photocurable composition with visible light having a wavelength of 405 nm at an irradiation dose of 11 mJ/ ^cm2 to form a cured layer having a thickness of 50 μm, and laminating the cured layer in the thickness direction to form a shaped object having a length of 39 mm, a width of 8 mm, and a thickness of 4 mm.
The photocurable composition according to claim 1 , which is produced by irradiating the shaped object with ultraviolet light having a wavelength of 365 nm at an irradiation dose of 10 J/cm ² . The photocurable composition according to claim 1, which is for photolithography. The photocurable composition according to any one of claims 1 to 11, which is used in the manufacture of dental products. A three-dimensional object that is a cured product of the photocurable composition according to claim 1. A dental product comprising the three-dimensional object according to claim 13. A (meth)acrylate represented by the following general formula (A-1a):

In formula (A-1a), X ^1A and X ^2A are urethane bonds, R ^1A is a monovalent organic group, R ^2A and R ^3A are each independently a divalent organic group, R ^4A is a methyl group or a hydrogen atom, and n ^A is 0 or 1. When n ^A is 0, at least one of R ^1A or R ^3A has a ring structure, and when n ^A is 1, at least one of R ^1A , R ^2A or R ^3A has a ring structure. The (meth)acrylate according to claim 15, represented by the following general formula (A-1a-1):

In formula (A-1a-1), R ^1A2 is a monovalent organic group, R ^2A2 and R ^3A2 are each independently a divalent organic group, R ^4A2 is a methyl group or a hydrogen atom, and at least one of R ^1A2 , R ^2A2 and R ^3A2 has a ring structure. A monomer composition comprising the (meth)acrylate according to claim 15. The monomer composition according to claim 17, which is for use in photolithography. The monomer composition according to claim 17, which is used in the manufacture of dental products.