Additive for polymerization, photopolymerization initiator, photocurable composition, and dental material

Abstract

This additive for polymerization contains a nitrogen-containing compound (1) represented by formula (1). In formula (1), R 1 is an aromatic heterocyclic group, and R 2 and R 3 are each independently a hydrogen atom or a monovalent organic group, or are bonded to each other and are a group that forms a heterocyclic ring and may have a substituent together with the nitrogen atom in formula (1).

Description

Polymerization additive, photopolymerization initiator, photocurable composition, and dental material

[0001] The present disclosure relates to a polymerization additive, a photopolymerization initiator, a photocurable composition, and a dental material.

[0002] Photopolymerization initiators have been used in various fields in recent years. For example, in the dental field, photopolymerization initiators are often used for the polymerization of dental curable compositions such as composite resins for repairing dental defects. Photopolymerization initiators in the dental field often contain photoradical generators such as camphorquinone (hereinafter also referred to as "CQ"), photobase generators, etc. In particular, the combination of "CQ" and a tertiary amine is one of the commonly used forms of dental photopolymerization initiators.

[0003] For example, Patent Document 1 discloses a combination of an α / diketone such as camphorquinone (CQ) and an aromatic hydrocarbon amine compound such as ethyl N,N-dimethylaminobenzoate as an example of a photopolymerization initiator used in dental restorative compositions such as the above-mentioned dental composite resin (hardenable composition).

[0004] Patent Document 1: Japanese Patent Application Laid-Open No. 2016-8211

[0005] There are cases where a photocurable composition is required to have excellent polymerization depth (that is, excellent polymerizability (i.e., curability) from the surface layer including the light-irradiated surface to deep portions).

[0006] For example, when a photocurable composition as a dental composition (e.g., a dental composite resin) is filled into a deep defect in a tooth, the photocurable composition may be required to have an excellent polymerization depth in order to sufficiently photocure the composition from the surface including the light-irradiated surface to the deep portion.

[0007] Photopolymerization initiators are also used as a component of photocurable compositions for stereolithography using 3D printers, which have become popular in recent years. Photocurable compositions for stereolithography are required to have the ability to produce a cured product with a consistent film thickness with a single light exposure when performing stereolithography using an accumulation method. To ensure this performance, photocurable compositions for stereolithography are also required to have an excellent polymerization depth.

[0008] Therefore, an object of one embodiment of the present disclosure is to provide a polymerization additive and a photopolymerization initiator that can improve the polymerization depth of a photocurable composition, a photocurable composition containing the photopolymerization initiator, and a dental material that contains at least one of the photocurable composition and its cured product.

[0009] Specific means for solving the above problems include the following aspects: <1> A polymerization additive containing a nitrogen-containing compound (1) represented by the following formula (1):

[0010]

[0011] In formula (1), R １ is an aromatic heterocyclic group, R ２ and R ３ are each independently a hydrogen atom or a monovalent organic group, or are groups which bond to each other to form, together with the nitrogen atom in formula (1), a heterocycle which may have a substituent.

[0012] <2> R １ <3> The polymerization additive according to <1>, wherein R is a pyrimidine ring group. ２ and R ３ are each independently an alkyl group or a group that is bonded to each other to form, together with the nitrogen atom in formula (1), a heterocycle that may have a substituent. <4> A photopolymerization initiator comprising a nitrogen-containing compound (1) represented by the following formula (1) and a photosensitizer:

[0013]

[0014] In formula (1), R １ is an aromatic heterocyclic group, R ２ and R ３ are each independently a hydrogen atom or a monovalent organic group, or are groups which bond to each other to form, together with the nitrogen atom in formula (1), a heterocycle which may have a substituent.

[0015] <5> A photocurable composition comprising a nitrogen-containing compound (1) represented by the following formula (1), a photosensitizer, and a monomer:

[0016]

[0017] In formula (1), R １ is an aromatic heterocyclic group, R ２ and R ３ are each independently a hydrogen atom or a monovalent organic group, or are groups which bond to each other to form, together with the nitrogen atom in formula (1), a heterocycle which may have a substituent.

[0018] <6> The photocurable composition according to <5>, wherein the photosensitizer comprises at least one selected from a 1,2-diketone compound and a benzoylcoumarin compound. <7> The photocurable composition according to <6>, wherein the 1,2-diketone compound is camphorquinone. <8> The photocurable composition according to any one of <5> to <7>, wherein the content of the photosensitizer and the content of the nitrogen-containing compound (1) relative to the total content of the photosensitizer are 0.5% by mass to 30% by mass. <9> The photocurable composition according to any one of <5> to <8>, wherein the photocurable composition does not contain an aromatic hydrocarbon amine compound, or, if it contains an aromatic hydrocarbon amine compound, the content of the aromatic hydrocarbon amine compound relative to the total amount of the photocurable composition is less than 0.01% by mass. <10> The photocurable composition according to any one of <5> to <9>, which does not contain a phosphine oxide compound, or if it contains one, the content of the phosphine oxide compound relative to the total amount of the photocurable composition is less than 0.01% by mass. <11> The photocurable composition according to any one of <5> to <10>, which corresponds to at least one of a composition for a dental material and a composition for stereolithography. <12> The photocurable composition according to any one of <5> to <11>, which is a composition for a dental material. <13> The photocurable composition according to any one of <5> to <11>, which is a composition for stereolithography. <14> A dental material comprising at least one of the photocurable composition according to any one of <5> to <13> and a cured product of the photocurable composition.

[0019] According to one embodiment of the present disclosure, there are provided a polymerization additive and a photopolymerization initiator that can improve the polymerization depth of a photocurable composition, a photocurable composition containing the photopolymerization initiator, and a dental material that contains at least one of the photocurable composition and a cured product thereof.

[0020] In the present disclosure, a numerical range indicated using "to" means a range that includes the numerical values ​​before and after "to" as the minimum and maximum values, respectively. In the numerical ranges described in stages in the present disclosure, the upper or lower limit value described in a certain numerical range may be replaced with the upper or lower limit value of another numerical range described in stages. Furthermore, in the numerical ranges described in the present disclosure, the upper or lower limit value described in a certain numerical range may be replaced with a value shown in the Examples. In the present disclosure, a combination of two or more preferred embodiments is a more preferred embodiment. In the present disclosure, when multiple substances corresponding to each component are present, the amount of each component refers to the total amount of multiple substances unless otherwise specified. In the present disclosure, "(meth)acrylic" means acrylic and methacrylic, and "(meth)acryloyl" means acryloyl and methacryloyl.

[0021] [Polymerization Additive] <Nitrogen-Containing Compound (1)> The polymerization additive of the present disclosure contains a nitrogen-containing compound (1) represented by the following formula (1). The polymerization additive of the present disclosure is used as a component of a photopolymerization initiator and / or a component of a photocurable composition. According to the polymerization additive of the present disclosure, the action of the nitrogen-containing compound (1) can improve the polymerization depth of the photocurable composition. In other words, the nitrogen-containing compound (1) is useful as an active ingredient in the polymerization additive for improving the polymerization depth of the photocurable composition.

[0022]

[0023] In formula (1), R １ is an aromatic heterocyclic group, R ２ and R ３ are each independently a hydrogen atom or a monovalent organic group, or are bonded to each other to form, together with the nitrogen atom in formula (1), a heterocycle which may have a substituent.

[0024] In formula (1), R １ The aromatic heterocyclic group represented by the formula (I) is preferably an aromatic heterocyclic group containing a nitrogen atom, more preferably an aromatic heterocyclic group having a 6-membered ring structure containing a nitrogen atom.

[0025] R １ Examples of the aromatic heterocyclic group represented by the formula (I) include a pyridine ring group, a pyrimidine ring group, and a triazine ring group. １ The aromatic heterocyclic group represented by the formula (I) is preferably a pyridine ring group (i.e., a pyridyl group) or a pyrimidine ring group (i.e., a pyrimidinyl group), and more preferably a pyrimidine ring group.

[0026] In formula (1), R ２ and R ３ are each independently a hydrogen atom or a monovalent organic group, or are bonded to each other to form, together with the nitrogen atom in formula (1), a heterocycle which may have a substituent.

[0027] R ２ and R ３ are each independently a hydrogen atom or a monovalent organic group, the monovalent organic group is preferably an alkyl group, more preferably an alkyl group having 1 to 20 carbon atoms (even more preferably 1 to 10, even more preferably 1 to 6, and even more preferably 1 to 3).

[0028] R ２ and R ３ are bonded to each other to form a heterocycle which may have a substituent together with the nitrogen atom in formula (1), the heterocycle is preferably a 5- or 6-membered ring, more preferably a 6-membered ring. The heterocycle is preferably a piperidine ring, a piperazine ring, a morpholine ring, or a pyrrolidine ring, more preferably a piperazine ring.

[0029] Examples of the substituent that may be substituted on the heterocycle include an alkyl group having 1 to 20 carbon atoms (more preferably 1 to 10, and even more preferably 1 to 6), an aryl group having 6 to 20 carbon atoms (more preferably 6 to 12), and an aralkyl group having 7 to 20 carbon atoms (more preferably 7 to 12). Examples of the aralkyl group having 7 to 20 carbon atoms include an unsubstituted benzyl group and the following groups, which are benzyl groups containing a substituent. In the following groups, * indicates the bonding position.

[0030]

[0031] The molecular weight of the nitrogen-containing compound (1) is preferably 1,000 or less, more preferably 500 or less, and even more preferably 400 or less. The lower limit of the molecular weight of the nitrogen-containing compound (1) is 100, for example.

[0032] One preferred embodiment of formula (1) is R ２ and R ３ are each independently an alkyl group, or are bonded to each other to form a heterocycle which may have a substituent together with the nitrogen atom in formula (1).

[0033] For specific examples of the nitrogen-containing compound (1), see the examples described later. In addition to the compounds in the examples described later, the following compounds are also specific examples.

[0034]

[0035] [Photopolymerization initiator] The photopolymerization initiator of the present disclosure contains the nitrogen-containing compound (1) and a photosensitizer. The photopolymerization initiator of the present disclosure can improve the polymerization depth of the photocurable composition due to the action of the nitrogen-containing compound (1). The photopolymerization initiator of the present disclosure may contain the polymerization additive of the present disclosure and a photosensitizer.

[0036] <Nitrogen-containing compound (1)> The photopolymerization initiator of the present disclosure contains at least one nitrogen-containing compound (1). The nitrogen-containing compound (1) in the photopolymerization initiator of the present disclosure is the same as the nitrogen-containing compound (1) in the polymerization additive of the present disclosure described above, and preferred embodiments are also the same.

[0037] In the photopolymerization initiator of the present disclosure, the proportion of the nitrogen-containing compound (1) to the total content of the nitrogen-containing compound (1) and the photosensitizer is preferably 70% by mass to 99.5% by mass, more preferably 80% by mass to 99.5% by mass.

[0038] <Photosensitizer> The photopolymerization initiator of the present disclosure contains at least one photosensitizer. Examples of the photosensitizer include a 1,2-diketone compound and a benzoylcoumarin compound.

[0039] The photosensitizer preferably contains at least one selected from a 1,2-diketone compound and a benzoylcoumarin compound. In this case, the total proportion of the 1,2-diketone compound and the benzoylcoumarin compound in the photosensitizer is preferably 50% by mass to 100% by mass, more preferably 70% by mass to 100% by mass, and even more preferably 80% by mass to 100% by mass.

[0040] Examples of the 1,2-diketone compound include camphorquinone (hereinafter also referred to as "CQ"), benzil, 2,3-pentanedione, 1,2-indandione, etc. As the 1,2-diketone compound, camphorquinone is particularly preferred.

[0041] Examples of the benzoylcoumarin compound include methoxybenzoylcoumarin, dimethoxybenzoylcoumarin, and diethylaminobenzoylcoumarin.

[0042] In the photopolymerization initiator of the present disclosure, the proportion of the photosensitizer relative to the total content of the nitrogen-containing compound (1) and the photosensitizer is preferably 0.5% by mass to 30% by mass, more preferably 0.5% by mass to 20% by mass.

[0043] The photopolymerization initiator of the present disclosure may or may not contain components other than the nitrogen-containing compound (1) and the photosensitizer. The total proportion of the nitrogen-containing compound (1) and the photosensitizer in the photopolymerization initiator of the present disclosure is preferably 50% by mass to 100% by mass, more preferably 70% by mass to 100% by mass, and even more preferably 80% by mass to 100% by mass.

[0044] <Preferred Uses> There are no particular limitations on the use of the photopolymerization initiator of the present disclosure, and it can be applied to any use in which an improvement in the polymerization depth of a photocurable composition is required. From the viewpoint of more effectively exhibiting the effect of improving the polymerization depth of a photocurable composition, it is preferable that the photopolymerization initiator of the present disclosure corresponds to at least one of a photopolymerization initiator for dental materials (i.e., a photopolymerization initiator contained in a photocurable composition for dental materials) and a photopolymerization initiator for stereolithography (i.e., a photopolymerization initiator contained in a photocurable composition for stereolithography).

[0045] [Photocurable composition] The photocurable composition of the present disclosure contains the nitrogen-containing compound (1), the photosensitizer, and a monomer. The photocurable composition of the present disclosure contains the nitrogen-containing compound (1), and therefore has excellent polymerization depth. The photocurable composition of the present disclosure may contain the polymerization additive of the present disclosure, the photosensitizer, and a monomer. The photocurable composition of the present disclosure may also contain the photopolymerization initiator of the present disclosure and a monomer.

[0046] <Nitrogen-Containing Compound (1)> The photocurable composition of the present disclosure contains at least one nitrogen-containing compound (1). The nitrogen-containing compound (1) in the photocurable composition of the present disclosure is the same as the nitrogen-containing compound (1) in the polymerization additive of the present disclosure, and preferred embodiments are also the same.

[0047] In the photocurable composition of the present disclosure, the proportion of the nitrogen-containing compound (1) relative to the total content of the nitrogen-containing compound (1) and the photosensitizer is preferably 70% by mass to 99.5% by mass, more preferably 80% by mass to 99.5% by mass.

[0048] In the photocurable composition of the present disclosure, the ratio of the content of the nitrogen-containing compound (1) to the content of the monomer is preferably 0.3% by mass to 10% by mass, more preferably 0.5% by mass to 5.0% by mass, and even more preferably 0.8% by mass to 4.0% by mass.

[0049] The photocurable composition of the present disclosure includes at least one photosensitizer. The photosensitizer in the photocurable composition of the present disclosure is the same as the photosensitizer in the photopolymerization initiator of the present disclosure, and preferred embodiments are also the same.

[0050] In the photocurable composition of the present disclosure, the proportion of the photosensitizer relative to the total content of the nitrogen-containing compound (1) and the photosensitizer is preferably 0.5% by mass to 30% by mass, more preferably 0.5% by mass to 20% by mass.

[0051] <Monomer> The photocurable composition of the present disclosure contains at least one monomer. As the monomer, a compound containing a radical polymerizable group is preferably used. As the radical polymerizable group, a group containing an ethylenic double bond is preferred, and a (meth)acryloyl group is particularly preferred.

[0052] The monomer preferably contains at least one (meth)acrylate compound. In this case, the proportion of the (meth)acrylate compound in the monomer is preferably 60% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more.

[0053] Examples of the (meth)acrylate compound include monofunctional (meth)acrylate compounds and difunctional or higher functional (meth)acrylate compounds. The (meth)acrylate compound preferably contains a difunctional or higher functional (meth)acrylate compound, more preferably contains a difunctional to hexafunctional (meth)acrylate compound, even more preferably contains a difunctional to tetrafunctional (meth)acrylate compound, and particularly preferably contains a difunctional (meth)acrylate compound (i.e., a di(meth)acrylate compound).

[0054] The bifunctional (meth)acrylate compound (i.e., di(meth)acrylate compound) is not particularly limited, and examples thereof include urethane di(meth)acrylate, neopentyl di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,8-octanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, tetrapropylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, 2,2-bis[4-(3-(meth)acryloyloxy-2-hydroxypropoxy)phenyl]propane, ethylene oxide-modified bisphenol A di(meth)acrylate, propylene oxide-modified bisphenol A di(meth)acrylate, and the like.

[0055] The proportion of the di(meth)acrylate compound in the monomer is preferably 60% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more.

[0056] The proportion of the di(meth)acrylate compound in the (meth)acrylate compound is preferably 60% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more.

[0057] The urethane di(meth)acrylate is preferably a reaction product of an isocyanate having two or more isocyanate groups and a (meth)acrylate having a hydroxy group (for example, hydroxyethyl methacrylate (HEMA)). The isocyanate having two or more isocyanate groups is preferably at least one selected from the group consisting of hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, pentamethylene diisocyanate, m-xylylene diisocyanate, 1,3-tetramethylxylylene diisocyanate, isophorone diisocyanate, bis(isocyanatemethyl)cyclohexane, bis(isocyanatecyclohexyl)methane, 2,5-bis(isocyanatemethyl)bicyclo-[2.2.1]-heptane, 2,6-bis(isocyanatemethyl)bicyclo-[2.2.1]-heptane, tolylene diisocyanate, phenylene diisocyanate, and 4,4'-diphenylmethane diisocyanate. The (meth)acrylate having a hydroxy group is preferably at least one selected from the group consisting of 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and 1,4-cyclohexanedimethanol mono(meth)acrylate.

[0058] For example, a urethane di(meth)acrylate that is the reaction product of a mixture of 2,2,4-trimethylhexamethylene diisocyanate and 2,4,4-trimethylhexamethylene diisocyanate with hydroxyethyl methacrylate (HEMA) is sometimes referred to as di-HEMA trimethylhexyl dicarbamate or di-HEMA trimethylhexyl dicarbamate.

[0059] The proportion of urethane di(meth)acrylate in the monomers is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 80% by mass or more.

[0060] For the monomer, for example, JP-A-11-315059, JP-A-2001-70437, JP-A-2011-105722, JP-A-2000-204069, JP-T-2013-544823, WO 2016 / 125758, WO 2015 / 119163 and other known documents may be referred to as appropriate.

[0061] The content of the monomer in the photocurable composition of the present disclosure is preferably 10% by mass or more, more preferably 20% by mass or more, and even more preferably 30% by mass or more, based on the total amount of the photocurable composition. The upper limit of the content of the monomer in the photocurable composition of the present disclosure is, for example, 99% by mass, based on the total amount of the photocurable composition.

[0062] <Filler> The photocurable composition of the present disclosure may contain a filler as needed. As the filler, for example, a general filler used in the dental field can be used. Fillers are generally broadly classified into organic fillers and inorganic fillers.

[0063] Examples of organic fillers include fine powders of polymethyl methacrylate, polyethyl methacrylate, methyl methacrylate-ethyl methacrylate copolymer, crosslinked polymethyl methacrylate, crosslinked polyethyl methacrylate, ethylene-vinyl acetate copolymer, styrene-butadiene copolymer, and the like.

[0064] Examples of inorganic fillers include fine powders of various glasses (mainly composed of silicon dioxide and optionally containing oxides of heavy metals, boron, aluminum, etc.), various ceramics, diatomaceous earth, kaolin, clay minerals (montmorillonite, etc.), activated clay, synthetic zeolite, mica, calcium fluoride, ytterbium fluoride, calcium phosphate, barium sulfate, zirconium dioxide, titanium dioxide, hydroxyapatite, etc. Specific examples of such inorganic fillers include barium borosilicate glass (Kimble Raysorb T3000, Schott 8235, Schott GM27884, Schott GM39923, etc.), strontium boroaluminosilicate glass (Raysorb T4000, Schott G018-093, Schott GM32087, etc.), lanthanum glass (Scott GM31684, etc.), fluoroaluminosilicate glass (Scott G018-091, Schott G018-117, etc.), and boroaluminosilicate glass containing zirconium, cesium, etc. (Scott G018-307, G018-308, G018-310, etc.).

[0065] Alternatively, an organic-inorganic composite filler may be used which is obtained by adding a monomer to an inorganic filler in advance, forming a paste, polymerizing and curing it, and then pulverizing it.

[0066] Furthermore, a photocurable composition containing microfillers with a particle size of 0.1 μm or less is one of the preferred embodiments for use as a photocurable composition for dental materials. Preferred materials for such small particle size fillers include silica (e.g., Aerosil), alumina, zirconia, and titania.

[0067] These fillers may be surface-treated with a surface treatment agent such as a silane coupling agent depending on the purpose. Examples of the surface treatment agent include known silane coupling agents, such as methacryloxyalkyltrimethoxysilane (number of carbon atoms between the methacryloxy group and the silicon atom: 3 to 12), methacryloxyalkyltriethoxysilane (number of carbon atoms between the methacryloxy group and the silicon atom: 3 to 12), vinyltrimethoxysilane, vinylethoxysilane, vinyltriacetoxysilane, and other organosilicon compounds.

[0068] When the photocurable composition of the present disclosure contains a filler, the content of the filler in the photocurable composition of the present disclosure is preferably 1% by mass or more, more preferably 10% by mass or more, more preferably 30% by mass or more, and even more preferably 50% by mass, relative to the total amount of the photocurable composition. The upper limit of the filler content, depending on the content of other components, is, for example, 90% by mass or less, 80% by mass or less, or 70% by mass or less, relative to the total amount of the photocurable composition.

[0069] The photocurable composition of the present disclosure may be substantially free of fillers. For example, the content of fillers in the photocurable composition of the present disclosure may be less than 1% by mass, based on the total amount of the photocurable composition.

[0070] <Other Components> The photocurable composition of the present disclosure may contain other components in addition to the components described above, as necessary. Examples of other components include polymerization inhibitors, non-polymerizable diluents (e.g., water), colorants (e.g., pigments or dyes), reinforcing materials (e.g., fibers), bactericides, disinfectants, stabilizers, preservatives, etc. For other components, reference may be made to the descriptions in known documents such as JP-A-11-315059, JP-A-2001-70437, JP-A-2011-105722, JP-A-2000-204069, JP-A-2013-544823, WO 2016 / 125758, and WO 2015 / 119163, as appropriate.

[0071] The photocurable composition of the present disclosure may not contain an aromatic hydrocarbon amine compound, or if it does contain one, the content of the aromatic hydrocarbon amine compound relative to the total amount of the photocurable composition may be less than 0.01% by mass (or less than 0.001% by mass). Even in these cases, the photocurable composition of the present disclosure exhibits excellent polymerization depth due to the action of the nitrogen-containing compound (1) in the photopolymerization initiator. Note that an aromatic hydrocarbon amine compound is one component that is sometimes used in conventional photopolymerization initiators. In the present disclosure, "aromatic hydrocarbon amine compound" refers to an amine containing an aromatic hydrocarbon structure. Examples of the aromatic hydrocarbon amine compound include aniline, toluidine, N-methylaniline, N-methyl-p-toluidine, N-phenylglycine, N-tolylglycine, N,N-(3-methacryloyloxy-2-hydroxypropyl)phenylglycine (NPG-GMA), N,N-dimethylaniline, N,N-dibenzylaniline, N,N-dimethyl-p-toluidine, N,N-diethyl-p-toluidine, N,N-di(2-hydroxyethyl)-p-toluidine, N,N-dimethyl-p-ethylaniline, N,N-dimethyl-p-isopropylaniline, N,N-dimethyl-p-tert-butylaniline, N,N-dimethylanisidine, N,N-dimethylxylidine, N,N-dimethyl-3,5-di-t-butylaniline, N,N-dimethyl-p-chloroaniline, and N,N-dimethyl-p-fluoroaniline.

[0072] The photocurable composition of the present disclosure may not contain a phosphine oxide compound, or if it contains one, the content of the phosphine oxide compound relative to the total amount of the photocurable composition may be less than 0.01% by mass (or less than 0.001% by mass). Even in these cases, the photocurable composition of the present disclosure exhibits excellent depth of polymerization due to the action of the nitrogen-containing compound (1) in the photopolymerization initiator. The phosphine oxide compound is one component that can be contained in conventional photopolymerization initiators. Examples of the phosphine oxide compound include acylphosphine oxide compounds such as 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,6-dimethoxybenzoyldiphenylphosphine oxide, and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide.

[0073] <Preferred Uses> There are no particular limitations on the uses of the photocurable composition of the present disclosure. The photocurable composition of the present disclosure can be used, for example, as a paint, a composition for forming a coating film, a composition for stereolithography (e.g., stereolithography using a 3D printer), a dental material, a component in a dental material, etc.

[0074] The photocurable composition of the present disclosure preferably corresponds to at least one of a composition for dental materials and a composition for stereolithography. Here, the photocurable composition for dental materials refers to a photocurable composition used as a dental material or as a component in a dental material. The photocurable composition of the present disclosure may correspond to both a composition for dental materials and a composition for stereolithography. For example, a dental material such as a denture base can be manufactured by stereolithography (e.g., stereolithography using a 3D printer) using a photocurable composition of the present disclosure that corresponds to both a composition for dental materials and a composition for stereolithography.

[0075] As described above, the photocurable composition of the present disclosure has excellent polymerization depth. Therefore, when the photocurable composition of the present disclosure is a dental material composition (e.g., a dental composite resin) and is used to fill a deep defect in a tooth, the photocurable composition of the present disclosure has excellent performance in sufficiently photocuring from the surface including the light-irradiated surface to the deep portion. Furthermore, when the photocurable composition of the present disclosure is a composition for stereolithography (e.g., stereolithography using a 3D printer) and is used for stereolithography using an accumulation method, the photocurable composition of the present disclosure has excellent performance in obtaining a cured product with a constant film thickness with a single light irradiation.

[0076] [Dental Material] The dental material of the present disclosure includes at least one of the above-described photocurable composition of the present disclosure and a cured product of the photocurable composition. The dental material of the present disclosure may also include other components as necessary.

[0077] Examples of dental materials of the present disclosure include dental restorative composite resins, denture base resins, denture base lining materials, impression materials, luting materials (resin cements, resin-added glass ionomer cements, etc.), dental adhesives (orthodontic adhesives, cavity application adhesives, etc.), fissure sealants, CAD / CAM resin blocks, temporary crowns, artificial tooth materials, etc. Examples of dental restorative composite resins include crown composite resins, caries cavity filling composite resins, core buildup composite resins, filling and restoration composite resins, etc. Dental restorative composite resins are particularly preferred as dental materials of the present disclosure.

[0078] Examples of the present disclosure will be shown below, but the present disclosure is not limited to the following examples. Each component used in the examples is shown below (where appropriate, the structure of the compound is also shown).

[0079] <Polymerization additive (nitrogen-containing compound (1))>

[0080]

[0081] <Polymerization additive (comparative additive)>

[0082]

[0083] <Photosensitizer>

[0084]

[0085] <Phosphine oxide compound> Omnirad 819: bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, manufactured by IGM Resins

[0086] <Monomer> PUA: urethane diacrylate (PUA), a reaction product of one molecule of m-xylylene diisocyanate and two molecules of phenyl glycidyl ether acrylate (the production method is shown below). —Production of PUA— 444 g (2.00 mol) of M-600A (phenyl glycidyl ether acrylate, manufactured by Kyoeisha Chemical Co., Ltd.), 0.63 g of DBTDL (dibutyltin dilaurate), and 0.32 g of MEHQ (4-methoxyphenol) were added to a 5-liter, four-necked flask equipped with a thoroughly dried stirring blade and a thermometer, and the mixture was stirred until homogeneous. The mixture was then heated to 60°C. Subsequently, 188 g (1.00 mol) of XDI (m-xylylene diisocyanate) was added dropwise over one hour. During the dropwise addition of XDI, the internal temperature rose due to the heat of reaction, so the amount added was controlled to maintain the temperature at 80°C or below. After the entire amount was added dropwise, the reaction temperature was maintained at 80°C and the reaction was carried out for 10 hours. The progress of the reaction was monitored by HPLC analysis to confirm the end point of the reaction. The product was discharged from the reactor to obtain 600 g of urethane diacrylate (PUA). The viscosity of the urethane diacrylate (PUA) at 65°C was 6,210 mPa s.

[0087] TEGDA: Triethylene glycol diacrylate POB-A: 3-phenoxybenzyl acrylate SR540: Epoxidized (4) bisphenol A dimethacrylate UDMA: Dicarbamic acid di-HEMA trimethylhexyl

[0088] <Polymerization inhibitor> BHT: dibutylhydroxytoluene

[0089] <Non-polymerizable diluent> H ２ O: water

[0090] <Filler> SG-YBG100: ytterbium fluoride manufactured by SG Japan, median diameter 100 nm GM27884 UF1.5 Sil2.3%: barium borosilicate glass manufactured by Shott, median diameter 1.5 μm

[0091] [Examples 1 and 2 and Comparative Examples 1 to 4] <Preparation of Photocurable Compositions> Photocurable compositions of Examples 1 and 2 and Comparative Examples 1 to 4 were prepared using the components shown in Table 1. The numbers in the component columns in Table 1 indicate the amount (parts by mass) of each component. A blank cell in Table 1 means that the corresponding component was not contained.

[0092] <Evaluation of polymerization depth (A)> Evaluation of polymerization depth (A) was carried out for each of the photocurable compositions of Examples 1 and 2 and Comparative Examples 1 to 4 as follows. First, the photocurable composition was poured into a transparent petri dish made of polypropylene (PP) to a thickness of 20 mm. In this state, 36 mJ / cm was applied to the photocurable composition from the back side of the transparent petri dish through the transparent petri dish. ２ The photocurable composition was partially cured by irradiating it with light of 1000 kJ / cm 2 , thereby obtaining a cured product. The obtained cured product was removed from the transparent petri dish, and the film thickness of the cured product was measured using a laser microscope manufactured by KYENCE. Based on the measured film thickness, the polymerization depth was evaluated (A) according to the following evaluation criteria. The results are shown in Table 1. In the polymerization depth evaluation (A), the photocurable composition with the best polymerization depth was ranked "5."

[0093] --Evaluation criteria for evaluation of polymerization depth (A)-- 5: The film thickness of the cured product was 0.55 mm or more. 4: The film thickness of the cured product was 0.50 mm or more and less than 0.55 mm. 3: The film thickness of the cured product was 0.40 mm or more and less than 0.50 mm. 2: The film thickness of the cured product was 0.30 mm or more and less than 0.40 mm. 1: The film thickness of the cured product was less than 0.30 mm, or no cured product was obtained.

[0094]

[0095] As shown in Table 1, the photocurable compositions of Examples 1 and 2, which used the nitrogen-containing compound (1) as a polymerization additive, were superior in polymerization depth compared to the photocurable compositions of Comparative Examples 1 and 2, which did not use the nitrogen-containing compound (1) as a polymerization additive, and the photocurable compositions of Comparative Examples 3 and 4, which used a comparative additive instead of the nitrogen-containing compound (1).

[0096] Examples 101 to 108 and Comparative Example 101 Preparation of Photocurable Compositions Photocurable compositions of Examples 101 to 108 and Comparative Example 101 were each prepared using the components shown in Table 2. The numbers in the component columns in Table 2 indicate the amount (parts by mass) of each component. A blank cell in Table 2 means that the corresponding component was not contained.

[0097] <Evaluation of Polymerization Depth (B)> For each of the photocurable compositions of Examples 101 to 108 and Comparative Example 101, the polymerization depth B was evaluated by the following method. A metal mold with a hole 4 mm in diameter and 15 mm deep was prepared, and the photocurable composition was poured into the hole. The exposed surface of the photocurable composition poured into the hole (i.e., the surface in contact with air) was covered with a 50 μm thick PET film (polyethylene terephthalate film), and the photocurable composition was irradiated with ultraviolet light through the PET film for 20 seconds. The ultraviolet light irradiation was performed using a Kulzer Translux 2wave. In this manner, the photocurable composition was cured by polymerizing the monomers in the photocurable composition, yielding a cured product. The obtained cured product was removed from the hole, and the length (mm) of the removed cured product was measured with a vernier caliper. Based on the measured length of the cured product, the polymerization depth (B) was evaluated according to the following evaluation criteria. The results are shown in Table 2. In the evaluation of polymerization depth (B), the most excellent polymerization depth of the photocurable composition is ranked "5".

[0098] <Evaluation> 5: The length of the cured product was 12 mm or more. 4: The length of the cured product was 11 mm or more and less than 12 mm. 3: The length of the cured product was 10 mm or more and less than 11 mm. 2: The length of the cured product was 9 mm or more and less than 10 mm. 1: The length of the cured product was less than 9 mm.

[0099]

[0100] As shown in Table 2, the photocurable compositions of Examples 101 to 108, which used nitrogen-containing compound (1) as the polymerization additive, were superior in polymerization depth compared to the photocurable composition of Comparative Example 101, which used a comparative additive instead of nitrogen-containing compound (1).

[0101] The disclosure of Japanese Patent Application No. 2023-127369, filed on August 3, 2023, is incorporated herein by reference in its entirety. All documents, patent applications, and technical standards described herein are incorporated herein by reference to the same extent as if each individual document, patent application, and technical standard was specifically and individually indicated to be incorporated by reference.

Claims

1. A polymerization additive comprising a nitrogen-containing compound (1) represented by the following formula (1): [In formula (1), R １ is an aromatic heterocyclic group; R ２ and R ３ are each independently a hydrogen atom or a monovalent organic group, or are a group which combines with each other to form a heterocycle, which may have a substituent, together with the nitrogen atom in formula (1).

2. R １ The polymerization additive according to claim 1 , wherein is a pyrimidine ring group.

3. R ２ and R ３ are each independently an alkyl group or a group which is bonded to each other to form a heterocycle, which may have a substituent, together with the nitrogen atom in formula (1).

4. A photopolymerization initiator comprising a nitrogen-containing compound (1) represented by the following formula (1) and a photosensitizer: [In formula (1), R １ is an aromatic heterocyclic group; R ２ and R ３ are each independently a hydrogen atom or a monovalent organic group, or are a group which combines with each other to form a heterocycle, which may have a substituent, together with the nitrogen atom in formula (1).

5. A photocurable composition comprising a nitrogen-containing compound (1) represented by the following formula (1), a photosensitizer, and a monomer: [In formula (1), R １ is an aromatic heterocyclic group; R ２ and R ３ are each independently a hydrogen atom or a monovalent organic group, or are a group which combines with each other to form a heterocycle, which may have a substituent, together with the nitrogen atom in formula (1).

6. The photocurable composition according to claim 5, wherein the photosensitizer comprises at least one selected from the group consisting of 1,2-diketone compounds and benzoylcoumarin compounds.

7. The photocurable composition according to claim 6, wherein the 1,2-diketone compound is camphorquinone.

8. The photocurable composition according to claim 5, wherein the content of the photosensitizer relative to the total content of the nitrogen-containing compound (1) and the photosensitizer is 0.5% by mass to 30% by mass.

9. The photocurable composition according to claim 5, which does not contain an aromatic hydrocarbon amine compound, or if it contains an aromatic hydrocarbon amine compound, the content of the aromatic hydrocarbon amine compound relative to the total amount of the photocurable composition is less than 0.01 mass%.

10. The photocurable composition according to claim 5, which does not contain a phosphine oxide compound, or if it contains one, the content of the phosphine oxide compound relative to the total amount of the photocurable composition is less than 0.01 mass%.

11. The photocurable composition according to claim 5, which corresponds to at least one of a composition for dental materials and a composition for stereolithography.

12. The photocurable composition according to claim 5, which is a dental material composition.

13. The photocurable composition according to claim 5, which is a composition for stereolithography.

14. A dental material comprising at least one of the photocurable composition according to claim 5 and a cured product of said photocurable composition.

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