JP7574526B2 - Polymerization initiator, kit for preparing hardenable composition, hardenable composition, hardened product, and dental material - Google Patents

Description

The present disclosure relates to a polymerization initiator, a kit for preparing a hardenable composition, a hardenable composition, a cured product, and a dental material.

In the field of dentistry, synthetic resin moldings are used to repair missing teeth. For example, to repair large missing teeth, hardenable compositions known as cements are used as tooth substitutes. In recent years, the range of uses for cement has been expanding.

Photoinitiators and chemical initiators can be used to polymerize dental hardenable compositions such as cements.
For example, Patent Document 1 discloses benzotriazole as an example of a chemical polymerization initiator used in cement.

Patent No. 5986496

However, benzotriazoles such as those described in Patent Document 1 may not be able to improve the polymerizability of monomers, and there is room for improvement in terms of polymerizability.

The problem to be solved by one embodiment of the present disclosure is to provide a polymerization initiator capable of satisfactorily improving the polymerizability of a monomer, a kit for preparing a curable composition containing the polymerization initiator, a curable composition, a cured product of the curable composition, and a dental material.

Specific means for solving the above problems include the following aspects.
<1> A polymerization initiator including a heterocyclic compound including a mercapto group and a monocyclic heterocycle.
<2> The polymerization initiator according to <1>, wherein the monocyclic heterocycle contains a nitrogen atom.
<3> The polymerization initiator according to <1> or <2>, wherein the monocyclic heterocycle is a 5-membered or 6-membered ring and contains at least one of a hydrocarbon group and an oxo group.
<4> The polymerization initiator according to any one of <1> to <3>, wherein the monocyclic heterocycle is a heteroaromatic ring.
<5> The polymerization initiator according to any one of <1> to <4>, wherein the monocyclic heterocycle contains two or more nitrogen atoms.
<6> The polymerization initiator according to any one of <1> to <5>, wherein the monocyclic heterocycle is an imidazole ring, a 1,2,4-triazole ring, a 1,3,4-thiadiazole ring, a 1,3-thiazole ring, a 1,3-oxazole ring, or a 1,2,3,4-tetrazole ring.
<7> The polymerization initiator according to any one of <1> to <6>, wherein the monocyclic heterocycle is a 5-membered ring.
<8> A kit for preparing a curable composition, comprising a first agent containing a monomer (A) and a second agent containing a monomer (B), in which the polymerization initiator, the transition metal compound, and the peroxide according to any one of <1> to <7> are each independently contained in at least one of the first agent and the second agent.
<9> The kit for preparing a curable composition according to <8>, wherein the polymerization initiator and the transition metal compound are contained in the first agent, and the peroxide is contained in the second agent.
<10> The kit for preparing a curable composition according to <8> or <9>, wherein the monomer (A) is a monomer containing no acidic group.
<11> The kit for preparing a curable composition according to any one of <8> to <10>, in which the monomer (B) includes an acidic group-containing monomer.
<12> The kit for preparing a curable composition according to any one of <8> to <11>, wherein the transition metal compound includes at least one of a copper compound and a vanadium compound.
<13> The kit for preparing a curable composition according to any one of <8> to <12>, wherein the peroxide includes an organic peroxide.
<14> The kit for preparing a curable composition according to any one of <8> to <13>, wherein a content of the heterocyclic compound relative to a total mass of the first agent and the second agent is 0.01% by mass to 5.0% by mass.
<15> The kit for preparing a hardenable composition according to any one of <8> to <14>, which is for use as a dental material.
<16> A curable composition comprising the polymerization initiator according to any one of <1> to <7>, a monomer, a transition metal compound, and a peroxide.
<17> A cured product of the curable composition according to <16>.
<18> A dental material comprising the cured product according to <17>.

According to one embodiment of the present disclosure, it is possible to provide a polymerization initiator capable of satisfactorily improving the polymerizability of a monomer, a kit for preparing a curable composition containing the polymerization initiator, a curable composition, a cured product of the curable composition, and a dental material.

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 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 the present disclosure. In addition, 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, combinations of two or more preferred aspects are more preferred aspects.
In the present disclosure, when there are multiple substances corresponding to each component, the amount of each component means the total amount of the multiple substances, unless otherwise specified.
In this disclosure, "(meth)acrylic" means acrylic and methacrylic, and "(meth)acryloyl" means acryloyl and methacryloyl.

<Polymerization initiator>
The polymerization initiator of the present disclosure includes a heterocyclic compound that includes a mercapto group and a monocyclic heterocycle.
The polymerization initiator of the present disclosure can satisfactorily improve the polymerizability by including a heterocyclic compound containing a mercapto group and a monocyclic heterocycle.
The polymerization initiator of the present disclosure is a chemical polymerization initiator that polymerizes monomers together by utilizing an oxidation-reduction reaction, and is different from the photopolymerization initiator described below.

<Heterocyclic compounds>
The heterocyclic compound contained in the polymerization initiator of the present disclosure contains a mercapto group and a monocyclic heterocycle.
In the heterocyclic compounds of the present disclosure, the mercapto group is preferably bonded to an atom other than a heteroatom in a monocyclic heterocycle (i.e., a carbon atom).

Examples of the heteroatom contained in the monocyclic heterocycle include a nitrogen atom, a sulfur atom, and an oxygen atom.
Among the above, a nitrogen atom and a sulfur atom are preferred, and a nitrogen atom is more preferred.

The number of heteroatoms contained in the monocyclic heterocycle is preferably 2 or more. Also, the number of heteroatoms contained in the monocyclic heterocycle is preferably 4 or less.
The heterocyclic compounds in the present disclosure preferably have a monocyclic heterocycle containing two or more nitrogen atoms.

The monocyclic heterocycle is preferably a 5- or 6-membered ring, more preferably a 5-membered ring.
The monocyclic heterocycle is preferably a heteroaromatic ring.

The monocyclic heterocycle may contain substituents.
Examples of the substituent include a monovalent organic group, an oxo group (=O), a thiooxo group (=S), and a halogen atom.
Among the above, as the substituent, a monovalent organic group and an oxo group are preferable, and a monovalent organic group is more preferable.

Examples of the monovalent organic group include a monovalent hydrocarbon group and a monovalent group containing a hetero atom and a carbon atom.
The monovalent organic group preferably has 1 to 10 carbon atoms, and more preferably has 1 to 6 carbon atoms.
The monovalent hydrocarbon group may be a linear or branched chain hydrocarbon group, or a cyclic hydrocarbon group. Of the above, the hydrocarbon group is preferably a cyclic hydrocarbon group.
Examples of the monovalent hydrocarbon group include a methyl group, an ethyl group, an isopropyl group, and a phenyl group.
Examples of the heteroatom in the monovalent group containing a heteroatom and a carbon atom include an oxygen atom, a sulfur atom, and a nitrogen atom.
Examples of the monovalent group containing a hetero atom and a carbon atom include a benzyl group, a methoxy group, and an ethoxy group.

It is preferred that the monocyclic heterocycle is a 5- or 6-membered ring and contains at least one of a hydrocarbon group and an oxo group.

Specific examples of the monocyclic heterocycle include an imidazole ring, a 1,2,4-triazole ring, a 1,3,4-thiadiazole ring, a 1,3-thiazole ring, a 1,3-oxazole ring, and a 1,2,3,4-tetrazole ring.
Among the above, the monocyclic heterocycle is preferably an imidazole ring, a 1,2,4-triazole ring, or a 1,3,4-thiadiazole ring.

Heterocyclic compounds include, for example, compounds represented by the following chemical formula:

<Curable composition preparation kit>
The kit for preparing a curable composition according to the present disclosure includes a first agent containing a monomer (A) and a second agent containing a monomer (B), and the polymerization initiator, transition metal compound, and peroxide according to the present disclosure are each independently contained in at least one of the first agent and the second agent.

<Monomer>
In the kit for preparing a curable composition of the present disclosure, the first part contains the monomer (A) and the second part contains the monomer (B).
The monomer (A) and the monomer (B) may be the same monomer or different monomers.
Known monomers can be used as the monomer (A) and the monomer (B). The monomer (A) and the monomer (B) may be a monomer that does not contain an acidic group, or may be a monomer that contains an acidic group.
The monomer (A) and the monomer (B) preferably include a monomer that does not contain an acidic group.

The monomer is a monomer that undergoes a radical polymerization reaction in the presence of the polymerization initiator of the present disclosure to become a polymer.
The monomer constituting the monomer in the present disclosure is not limited to one type, and may be two or more types. The monomer not containing an acidic group may be a (meth)acrylate monomer not containing an acidic group. The (meth)acrylate monomer not containing an acidic group may be a monofunctional monomer, a bifunctional monomer, or a trifunctional or higher functional monomer.

In the present disclosure, the content of the monomers (i.e., the total amount of monomer (A) and monomer (B) in the curable composition to be prepared) is preferably 10% by mass to 90% by mass, more preferably 20% by mass to 75% by mass, and even more preferably 30% by mass to 60% by mass, based on the total mass of the curable composition to be prepared.

Examples of monofunctional monomers include 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 1,3-dihydroxypropyl (meth)acrylate, and 2,3-dihydroxypropyl (meth)acrylate. Of these, 2-hydroxyethyl methacrylate (HEMA) is preferred.

Examples of aromatic bifunctional monomers include 2,2-bis((meth)acryloyloxyphenyl)propane, 2,2-bis[4-(3-(meth)acryloyloxy)-2-hydroxypropoxyphenyl]propane, 2,2-bis(4-(meth)acryloyloxyethoxyphenyl)propane, 2,2-bis(4-(meth)acryloyloxypolyethoxyphenyl)propane, 2,2-bis(4-(meth)acryloyloxypolypropoxyphenyl)propane, and the like.
Among these, 2,2-bis[4-(3-(methacryloyloxy)-2-hydroxypropoxyphenyl]propane (commonly known as “Bis-GMA”) and 2,2-bis(4-methacryloyloxypolyethoxyphenyl)propane are preferred.

Examples of aliphatic compound-based bifunctional monomers include erythritol di(meth)acrylate, sorbitol di(meth)acrylate, mannitol di(meth)acrylate, pentaerythritol di(meth)acrylate, dipentaerythritol di(meth)acrylate, glycerol di(meth)acrylate, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, butylene glycol di(meth)acrylate, acrylate, neopentyl glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, 1,3-butanediol di(meth)acrylate, 1,5-pentanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, 2,2,4-trimethylhexamethylenebis(2-carbamoyloxyethyl)dimethacrylate (UDMA), 1,2-bis(3-methacryloyloxy-2-hydroxypropyloxy)ethane, and the like.
Among these, glycerol dimethacrylate, triethylene glycol dimethacrylate (TEGDMA), 1,6-hexanediol dimethacrylate (HexDMA), neopentyl glycol dimethacrylate (NPG), 2,2,4-trimethylhexamethylenebis(2-carbamoyloxyethyl)dimethacrylate (UDMA) and 1,2-bis(3-methacryloyloxy-2-hydroxypropyloxy)ethane are preferred.

Examples of trifunctional or higher monomers include trimethylolpropane tri(meth)acrylate, trimethylolethane tri(meth)acrylate, trimethylolmethane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol tri(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, N,N-(2,2,4-trimethylhexamethylene)bis[2-(aminocarboxy)propane-1,3-diol]tetramethacrylate, 1,7-diacryloyloxy-2,2,6,6-tetraacryloyloxymethyl-4-oxyheptane, etc.

The above monomers may be used alone or in combination.

The amount of the monomer not containing an acidic group is preferably in the range of 10 parts by mass to 100 parts by mass, more preferably in the range of 20 parts by mass to 100 parts by mass, and even more preferably in the range of 5 parts by mass to 100 parts by mass, relative to 100 parts by mass of the total amount of the monomer components in the kit for preparing a curable composition of the present disclosure.
Furthermore, when the monomer components in the curable composition preparation kit of the present disclosure include an acidic group-containing monomer, the blending amount of the monomer not containing an acidic group is preferably 10 parts by mass to 99 parts by mass, more preferably 30 parts by mass to 97 parts by mass, and even more preferably 50 parts by mass to 95 parts by mass, relative to 100 parts by mass of the total amount of the monomer components in the curable composition preparation kit of the present disclosure.

<Acidic Group-Containing Monomer>
In the kit for preparing a curable composition of the present disclosure, the acidic group-containing monomer may be contained in at least one of the first agent and the second agent.
By containing an acidic group-containing monomer in at least one of the first agent and the second agent, for example, when the hardenable composition preparation kit of the present disclosure is used for dental applications, good tooth structure and high adhesion to dental prosthetic materials can be imparted.

Examples of the acidic group-containing monomer include monomers having at least one acidic group, such as a phosphoric acid group, a pyrophosphoric acid group, a thiophosphoric acid group, a phosphonic acid group, a sulfonic acid group, or a carboxylic acid group, and having at least one polymerizable group, such as an acryloyl group, a methacryloyl group, a vinyl group, or a styrene group.
The acidic group-containing monomer has an affinity for the adherend and has a demineralizing effect on tooth structure.

Examples of phosphate group-containing monomers include (meth)acryloyloxyalkyl dihydrogen phosphates such as 10-(meth)acryloyloxydecyl dihydrogen phosphate (MDP), bis[2-(meth)acryloyloxyethyl]hydrogen phosphate, bis[4-(meth)acryloyloxybutyl]hydrogen phosphate, bis[6-(meth)acryloyloxyhexyl]hydrogen phosphate, bis[8-(meth)acryloyloxyoctyl]hydrogen phosphate, bis[9-(meth)acryloyloxy Examples include bis[10-(meth)acryloyloxydecyl]hydrogen phosphate, 1,3-di(meth)acryloyloxypropyl dihydrogen phosphate, 2-(meth)acryloyloxyethylphenyl hydrogen phosphate, 2-(meth)acryloyloxyethyl-2-bromoethyl hydrogen phosphate, bis[2-(meth)acryloyloxy-(1-hydroxymethyl)ethyl]hydrogen phosphate, and their acid chlorides, alkali metal salts, and ammonium salts.

Examples of pyrophosphate group-containing monomers include bis[2-(meth)acryloyloxyethyl]pyrophosphate, bis[4-(meth)acryloyloxybutyl]pyrophosphate, and their acid chlorides, alkali metal salts, and ammonium salts.

Examples of thiophosphate group-containing monomers include 2-(meth)acryloyloxyethyl dihydrogen thiophosphate, 3-(meth)acryloyloxypropyl dihydrogen thiophosphate, and their acid chlorides, alkali metal salts, and ammonium salts.

Examples of phosphonic acid group-containing monomers include 2-(meth)acryloyloxyethyl phenylphosphonate, 5-(meth)acryloyloxypentyl-3-phosphonopropionate, and their acid chlorides, alkali metal salts, and ammonium salts.

Examples of sulfonic acid group-containing monomers include 2-(meth)acrylamido-2-methylpropanesulfonic acid, styrenesulfonic acid, and 2-sulfoethyl(meth)acrylate.

Carboxylic acid group-containing monomers include monomers that have one carboxy group in the molecule and monomers that have multiple carboxy groups in the molecule.

Monomers having one carboxy group in the molecule include (meth)acrylic acid, N-(meth)acryloylglycine, N-(meth)acryloylaspartic acid, O-(meth)acryloyltyrosine, N-(meth)acryloyltyrosine, N-(meth)acryloylphenylalanine, N-(meth)acryloyl-p-aminobenzoic acid, N-(meth)acryloyl-o-aminobenzoic acid, p-vinylbenzoic acid, and 2-(meth)acryloyloxybenzoic acid. Examples include acryloyloxybenzoic acid, 3-(meth)acryloyloxybenzoic acid, 4-(meth)acryloyloxybenzoic acid, N-(meth)acryloyl-5-aminosalicylic acid, N-(meth)acryloyl-4-aminosalicylic acid, 2-(meth)acryloyloxyethyl hydrogen succinate, 2-(meth)acryloyloxyethyl hydrogen phthalate, 2-(meth)acryloyloxyethyl hydrogen maleate, and acid halides thereof.

Examples of monomers having multiple carboxy groups in the molecule include 6-(meth)acryloyloxyhexane-1,1-dicarboxylic acid, 9-(meth)acryloyloxynonane-1,1-dicarboxylic acid, 10-(meth)acryloyloxydecane-1,1-dicarboxylic acid, 11-(meth)acryloyloxyundecane-1,1-dicarboxylic acid, 12-(meth)acryloyloxydodecane-1,1-dicarboxylic acid, 13-(meth)acryloyloxytridecane-1,1-dicarboxylic acid, 4 ...4-(meth)acryloyloxyhexane-1,1-dicarboxylic acid, 4-(meth)acryloyloxyhexane-1,1-dicarboxylic acid, 4-(meth)acryloyloxyhexane-1,1-dicarboxylic acid, 4-(meth)acryloyloxyhexane-1,1-dicarboxylic acid, 4-(meth)acryloyloxyhexane-1,1-dicarboxylic acid, 4-(meth)acryloyloxyhexane-1,1-dicarboxylic acid, 4-(meth)acryloyloxyhexane-1,1-dicarboxylic acid, 4-(meth)acryloyloxyhexane-1,1-dicarboxylic acid, 4-(meth)acryloyloxyhexane-1,1-dicarboxylic acid, 4-(meth)acryloyl Examples include acryloyloxyethyl trimellitate, 4-(meth)acryloyloxyethyl trimellitate anhydride, 4-(meth)acryloyloxybutyl trimellitate, 4-(meth)acryloyloxyhexyl trimellitate, 4-(meth)acryloyloxydecyl trimellitate, 2-(meth)acryloyloxyethyl-3'-(meth)acryloyloxy-2'-(3,4-dicarboxybenzoyloxy)propyl succinate, and acid anhydrides or acid halides thereof.

Among the above-mentioned acidic group-containing monomers, 10-(meth)acryloyloxydecyl dihydrogen phosphate (MDP), 1,3-di(meth)acryloyloxypropyl dihydrogen phosphate, 2-(meth)acryloyloxyethyl dihydrogen phosphate, 4-(meth)acryloyloxyethyl trimellitate anhydride, 4-(meth)acryloyloxyethyl trimellitate, 2-(meth)acrylamido-2-methylpropanesulfonic acid, and 11-(meth)acryloyloxyundecane-1,1-dicarboxylic acid are preferred in terms of their high adhesive strength to the adherend.
The above-mentioned acidic group-containing monomers may be used alone or in combination of two or more kinds.

The amount of the acidic group-containing monomer is preferably 1 part by mass to 50 parts by mass, more preferably 3 parts by mass to 40 parts by mass, and even more preferably 5 parts by mass to 30 parts by mass, relative to 100 parts by mass of the total amount of the monomer components in the kit for preparing a curable composition of the present disclosure.
When the amount of the acidic group-containing monomer is 1 part by mass or more, high adhesion to various adherends can be easily obtained.
In addition, when the amount of the acidic group-containing monomer is 50 parts by mass or less, it is easy to maintain a balance between polymerizability and adhesiveness. The total amount of the monomer components means the total amount of the acidic group-containing monomer and the monomer not containing an acidic group.

The monomers used in this disclosure may be those described in known documents such as WO 2012/157566, WO 2015/015220, WO 2015/015221, and JP 2016-094482.

<Transition metal compounds>
In the kit for preparing a curable composition of the present disclosure, a transition metal compound is contained in at least one of the first agent and the second agent.
The transition metal compound is preferably a compound that is soluble in the monomer component.

Examples of the transition metal compound include a copper compound, a vanadium compound, a molybdenum compound, a scandium compound, a titanium compound, a chromium compound, a manganese compound, an iron compound, a cobalt compound, and a nickel compound.
Among the above, it is preferable that the transition metal compound contains at least one of a copper compound and a vanadium compound.

Examples of copper compounds include copper carboxylates such as copper acetate, copper isobutyrate, copper gluconate, copper citrate, copper phthalate, copper tartrate, copper oleate, copper octylate, copper octenate, copper naphthenate, copper methacrylate, and copper 4-cyclohexylbutyrate; β-diketone coppers such as copper acetylacetone, copper trifluoroacetylacetone, copper hexafluoroacetylacetone, copper 2,2,6,6-tetramethyl-3,5-heptanedionato, and copper benzoylacetone; β-ketoester coppers such as copper ethyl acetoacetate; copper alkoxides such as copper methoxide, copper ethoxide, copper isopropoxide, copper 2-(2-butoxyethoxy)ethoxide, and copper 2-(2-methoxyethoxy)ethoxide; copper dithiocarbamate such as copper dimethyldithiocarbamate; and salts of copper and inorganic acids such as copper nitrate and copper chloride.
These may be used alone or in appropriate combination of two or more.
Among these, copper carboxylate, copper β-diketone and copper β-ketoester are preferred, with copper acetate and copper acetylacetonate being particularly preferred, from the viewpoints of solubility and reactivity in monomers.

Examples of vanadium compounds include vanadyl acetylacetonate, vanadium naphthenate (III), vanadyl stearate, vanadium benzoylacetonate, bis(maltolate)oxovanadium (IV), and oxobis(1-phenyl-1,3-butanedionate)vanadium (IV).

From the viewpoint of curability, the amount of the transition metal compound is preferably 0.000005 parts by mass to 0.01 parts by mass, more preferably 0.00001 parts by mass to 0.005 parts by mass, and most preferably 0.00005 parts by mass to 0.001 parts by mass, relative to 100 parts by mass of the total amount of the monomer components in the kit for preparing a curable composition of the present disclosure.

<Peroxide>
In the kit for preparing a curable composition of the present disclosure, a peroxide is contained in at least one of the first agent and the second agent.
Peroxides include organic peroxides and inorganic peroxides, and it is preferred that the peroxide in the present disclosure comprises an organic peroxide.

The organic peroxide is not particularly limited and any known organic peroxide can be used. Representative organic peroxides include hydroperoxides, peroxyesters, ketone peroxides, peroxyketals, dialkyl peroxides, diacyl peroxides, and peroxydicarbonates. Among these, hydroperoxides are most preferred because there is little change in the operable time even when the curable composition is provided in a package and stored for a long period of time. One type of organic peroxide may be used alone, or multiple types may be used in combination.

More specifically, examples of hydroperoxides include cumene hydroperoxide, t-butyl hydroperoxide, t-hexyl hydroperoxide, p-menthane hydroperoxide, diisopropylbenzene hydroperoxide, and 1,1,3,3-tetramethylbutyl hydroperoxide.

Any known peroxy ester can be used without any restrictions as long as it has an acyl group on one side of a peroxy group (-OO- group) and a hydrocarbon group (or a group similar thereto) on the other side. Specific examples include α,α-bis(neodecanoylperoxy)diisopropylbenzene, cumyl peroxy neodecanoate, 1,1,3,3-tetramethylbutyl peroxy neodecanoate, 1-cyclohexyl-1-methylethyl peroxy neodecanoate, t-hexyl peroxy neodecanoate, t-butyl peroxy neodecanoate, t-hexyl peroxy pivalate, t-butyl peroxy pivalate, 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate, 2,5-dimethyl-2,5-bis(2-ethylhexanoylperoxy)hexane, 1-cyclohexyl-1-methylethyl peroxy-2-ethylhexanoate, t-hexyl peroxy 2-ethylhexanoate, and t-butyl peroxy 2-ethylhexanoate. Examples include tert-butylperoxy isobutyrate, tert-hexylperoxy isopropyl monocarbonate, tert-butylperoxy maleic acid, tert-butylperoxy 3,5,5-trimethylhexanoate, tert-butylperoxy laurate, 2,5-dimethyl-2,5-bis(m-toluoylperoxy)hexane, tert-butylperoxy isopropyl monocarbonate, tert-butylperoxy 2-ethylhexyl monocarbonate, tert-hexylperoxybenzoate, 2,5-dimethyl-2,5-bis(benzoylperoxy)hexane, tert-butylperoxy acetate, tert-butylperoxy-m-toluoyl benzoate, tert-butylperoxybenzoate, bis(t-butylperoxy)isophthalate, etc. These can be used alone or in appropriate combinations of two or more.

Examples of ketone peroxides include methyl ethyl ketone peroxide, cyclohexano peroxide, methylcyclohexanone peroxide, methyl acetoacetate peroxide, and acetylacetone peroxide.

Examples of peroxyketals include 1,1-bis(t-hexylperoxy)3,3,5-trimethylcyclohexane, 1,1-bis(t-hexylperoxy)cyclohexane, 1,1-bis(t-butylperoxy)3,3,5-trimethylcyclohexanone, 1,1-bis(t-butylperoxy)cyclohexane, 1,1-bis(t-butylperoxy)cyclodecane, 2,2-bis(t-butylperoxy)butane, n-butyl 4,4-bis(t-butylperoxy)valerate, and 2,2-bis(4,4-di-t-butylperoxycyclohexyl)propane.

Examples of dialkyl peroxides include α,α-bis(t-butylperoxy)diisopropylbenzene, dicumyl peroxide, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexane, t-butylcumyl peroxide, di-t-butyl peroxide, and 2,5-dimethyl-2,5-bis(t-butylperoxy)hexane-3.

Diacyl peroxides include isobutyryl peroxide, 2,4-dichlorobenzoyl peroxide, 3,5,5-trimethylhexanoyl peroxide, octanoyl peroxide, lauroyl peroxide, stearyl peroxide, succinic acid peroxide, m-toluoylbenzoyl peroxide, and benzoyl peroxides.

Examples of peroxydicarbonates include di-n-propyl peroxydicarbonate, diisopropyl peroxydicarbonate, bis(4-t-butylcyclohexyl) peroxydicarbonate, di-2-ethoxyethyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, di-2-methoxybutyl peroxydicarbonate, and di(3-methyl-3-methoxybutyl) peroxydicarbonate.

From the viewpoint of curability, the amount of organic peroxide is preferably 0.01 parts by mass to 1 part by mass, and more preferably 0.05 parts by mass to 0.5 parts by mass, per 100 parts by mass of the total amount of the monomer components in the curable composition of the present disclosure.

Inorganic peroxides include peroxodisulfates and peroxodiphosphates, and among these, peroxodisulfates are preferred in terms of curability. Specific examples of peroxodisulfates include sodium peroxodisulfate, potassium peroxodisulfate, aluminum peroxodisulfate, and ammonium peroxodisulfate.

The above peroxodisulfates may be used alone or in combination. Among the above peroxodisulfates, sodium peroxodisulfate, potassium peroxodisulfate, and ammonium peroxodisulfate are preferred.

<Filler>
In the kit for preparing a curable composition of the present disclosure, a filler may be contained in at least one of the first agent and the second agent.
The filler may be used alone or in combination of two or more kinds. Examples of the filler include inorganic fillers, organic fillers, and composite fillers of inorganic fillers and organic fillers.

Examples of inorganic fillers include silica; minerals based on silica, such as kaolin, clay, mica _, and mica; ceramics and glasses based on silica and containing _Al2O3 , _{B2O3 , TiO2} , _{ZrO2 , BaO} , _La2O3 , SrO, ZnO, CaO, _P2O5 , _Li2O , _Na2O , etc. Examples of glasses that are preferably used include lanthanum glass, barium glass, strontium glass, soda glass, lithium borosilicate glass, zinc glass, fluoroaluminosilicate glass, borosilicate glass, and bioglass. Crystalline quartz, hydroxyapatite, alumina, titanium oxide, yttrium oxide, zirconia, calcium phosphate, barium sulfate, aluminum hydroxide, sodium fluoride, potassium fluoride, sodium monofluorophosphate, lithium fluoride, and ytterbium fluoride are also preferably used. Specifically, in terms of adhesive strength and ease of handling, fine particle silica having a primary particle size of 0.001 μm to 0.1 μm is preferably used. Commercially available products include "Aerosil OX50", "Aerosil 50", "Aerosil 200", "Aerosil 380", "Aerosil R972", and "Aerosil 130" (all manufactured by Nippon Aerosil Co., Ltd.).

Examples of organic fillers include polymethyl methacrylate, polyethyl methacrylate, polyfunctional methacrylate polymers, polyamide, polystyrene, polyvinyl chloride, chloroprene rubber, nitrile rubber, and styrene-butadiene rubber.

Examples of composite fillers made of inorganic and organic fillers include inorganic fillers dispersed in organic fillers, and inorganic/organic composite fillers made of inorganic fillers coated with various polymers.

To improve curability, mechanical strength, and ease of handling, the filler may be surface-treated with a known surface treatment agent such as a silane coupling agent before use. Examples of surface treatment agents include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltrichlorosilane, vinyltri(β-methoxyethoxy)silane, γ-methacryloyloxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, and γ-aminopropyltriethoxysilane.

The amount of filler is preferably in the range of 10% by mass to 80% by mass, more preferably in the range of 30% by mass to 80% by mass, and most preferably in the range of 50% by mass to 75% by mass, based on the total mass of the curable composition of the present disclosure.

<Reducing Agent>
In the kit for preparing a curable composition of the present disclosure, a reducing agent may be contained in at least one of the first agent and the second agent.
The reducing agent may be a known reducing agent, for example, a sulfinic acid compound or a salt thereof, an amine compound or a salt thereof, a hydrazine compound or a salt thereof, an ascorbic acid compound or a salt thereof, or the like.

Examples of the sulfinic acid compound or a salt thereof include alkane sulfinic acids or a salt thereof, alicyclic sulfinic acids or a salt thereof, and aromatic sulfinic acids or a salt thereof.
Examples of the salts of sulfinic acid compounds include lithium salts, sodium salts, potassium salts, rubidium salts, cesium salts, magnesium salts, calcium salts, strontium salts, iron salts, zinc salts, ammonium salts, tetramethylammonium salts, and tetraethylammonium salts.

Examples of the alkanesulfinic acids include methanesulfinic acid.
Examples of alicyclic sulfinic acids include cyclohexanesulfinic acid and cyclooctanesulfinic acid.
Examples of aromatic sulfinic acids include benzenesulfinic acid, p-toluenesulfinic acid, o-toluenesulfinic acid, ethylbenzenesulfinic acid, decylbenzenesulfinic acid, dodecylbenzenesulfinic acid, 2,4,6-trimethylbenzenesulfinic acid, 2,4,6-triisopropylbenzenesulfinic acid, chlorobenzenesulfinic acid, and naphthalenesulfinic acid.

Examples of hydrazine compounds or salts thereof include adipic dihydrazide, isophthalic dihydrazide, azelaic dihydrazide, acetohydrazide, benzoylhydrazine, tert-butyl 2-methylcarbazate, carbohydrazide, N,N'-dibenzoylhydrazine, malonic hydrazide, phthalic hydrazide, acetylphenylhydrazine, and salts of these hydrazine compounds.

Examples of the amine compound or a salt thereof include an aromatic substituted glycine compound or a salt thereof, and an aromatic tertiary amine.
Examples of the salts of the aromatic substituted glycine compounds include alkali metal salts, alkaline earth metal salts, amine salts, and ammonium salts.
Examples of aromatic tertiary amines include N,N-dimethylaniline (DMA), N,N-dimethyl p-toluidine (DMPT), N,N-diethyl p-toluidine, N,N-diethanol p-toluidine (DEPT), methyl N,N-dimethylaminobenzoate, ethyl N,N-dimethylaminobenzoate (DMABAE), butoxyethyl N,N-dimethylaminobenzoate (DMABABE), N,N-diethylaminobenzoic acid (DEABA) and its alkyl esters, N,N-dimethylaminobenzaldehyde (DMABAd), and N,N-dimethylaminobenzophenone.

<Other Ingredients>
The curable composition of the present disclosure may contain additives such as a photopolymerization initiator, a stabilizer (polymerization inhibitor), a colorant, a fluorescent agent, and an ultraviolet absorber, water, etc. As the photopolymerization initiator, a known photopolymerization initiator can be used, and examples thereof include camphorquinone (CQ), ethyl dimethylaminobenzoate (EDB), etc.
In addition, antibacterial substances such as cetylpyridinium chloride, benzalkonium chloride, (meth)acryloyloxydodecylpyridinium bromide, (meth)acryloyloxyhexadecylpyridinium chloride, (meth)acryloyloxydecylammonium chloride, and triclosan may be added.
The curable composition of the present disclosure may contain known dyes and pigments.

In the kit for preparing a curable composition of the present disclosure, it is preferable that the polymerization initiator and transition metal compound of the present disclosure are contained in a first agent, and the peroxide is contained in a second agent.
By storing the polymerization initiator, the transition metal compound, and the peroxide separately as the first and second agents, it is possible to prevent the polymerization of the monomer from being unintentionally initiated, thereby improving the storage stability of the kit for preparing the curable composition.
In this case, polymerization of the monomer is initiated when the polymerization initiator, the transition metal compound, and the peroxide are mixed together.

It is preferred that the monomer (A) is a monomer that does not contain an acidic group.
In particular, when the polymerization initiator and transition metal compound of the present disclosure are contained in the first agent, by using monomer (A) as a monomer that does not contain an acidic group, it is possible to suppress unintended initiation of polymerization due to reaction of the acidic group with the polymerization initiator and the transition metal compound.

When it is desired to impart adhesive properties to the curable composition, it is preferred that the monomer (B) contains an acidic group-containing monomer.
In particular, when the second agent contains a peroxide, the initiation of polymerization can be suppressed even if the monomer (B) contains an acidic group-containing monomer, i.e., the timing at which polymerization of the monomer is initiated can be adjusted.

Both the first and second agents may contain a filler, a reducing agent, a photopolymerization initiator, and the like.
From the viewpoint of reactivity, the reducing agent is preferably contained in the first agent.

In the curable composition preparation kit of the present disclosure, the content of the heterocyclic compound contained in the polymerization initiator relative to the total mass of the first agent and the second agent is preferably 0.01% by mass to 5.0% by mass, more preferably 0.01% by mass to 1.0% by mass, and even more preferably 0.01% by mass to 0.1% by mass.

The hardenable composition preparation kit of the present disclosure is preferably for use in dental materials.

<Curable Composition>
The curable composition of the present disclosure includes the polymerization initiator of the present disclosure, a monomer, a transition metal compound, and a peroxide. When the curable composition of the present disclosure includes the above-mentioned components, the polymerizability can be improved.

<Cured Product>
The cured product of the present disclosure is a cured product of the curable composition of the present disclosure, or a cured product obtained using the kit for preparing a curable composition of the present disclosure.
The cured product of the present disclosure can be suitably used as a dental material. That is, the dental material of the present disclosure preferably contains the cured product of the present disclosure.

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

The following are examples of the present disclosure, but the present disclosure is not limited to the following examples.

The polymerization initiator and curable composition used in the examples of this disclosure are described below.

<Monomer>
The following monomers were prepared:
UDMA: dimethacryloxyethyl trimethylhexyl dicarbamate NPG: neopentyl glycol dimethacrylate MDP: methacryloxydecyl phosphate

<Polymerization inhibitor>
The following polymerization inhibitors were prepared:
BHT: Dibutyl hydroxytoluene MEHQ: Methoquinone

<Transition metal compounds>
The following transition metal compounds were prepared:
Cu(acac) ₂ : copper acetylacetonate VO(acac) ₂ : vanadyl acetylacetonate

<Organic Peroxide>
The following organic peroxides were prepared:
CHP: Cumene hydroperoxide

<Photopolymerization initiator>
The following photopolymerization initiators were prepared:
CQ: Camphorquinone EDB: Ethyl dimethylaminobenzoate

<Filler>
The following fillers were prepared:
GM27884: Barium aluminum silicate, 1.5 μm, silane coupling agent treatment amount 2.3%

<Monocyclic heterocyclic compound having a mercapto group>
As the monocyclic heterocyclic compound having a mercapto group, the following was prepared.
MT: mercaptotriazole MTT: methylthiadiazole thiol MMI: mercaptomethylimidazole PhMT: phenylmercaptotriazole

<Heterocyclic compound not having a mercapto group>
As heterocyclic compounds not having a mercapto group, the following were prepared.
BTA: benzotriazole TA: triazole AMTTA: aminomethylthiotriazole The structural formulae of the monocyclic heterocyclic compound having a mercapto group and the heterocyclic compound not having a mercapto group are as follows.

<Reducing Agent>
The following reducing agents were prepared:
pTSS: paratoluenesulfinic acid sodium

[Examples 1 to 5 and Comparative Examples 1 to 3]
<Preparation of Curable Composition>
The components shown in Table 1 below were weighed out and placed in a light-shielding bottle to prepare a first part and a second part. Next, the first part and the second part were mixed and stirred for 10 minutes using a planetary centrifugal mixer manufactured by THINKY Corporation under conditions of 20 kPa and 2000 rpm (revolutions per minute) to obtain the curable compositions of Examples 1 to 5 and Comparative Examples 1 to 3.
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 component was not used.

<Evaluation of Monomer Polymerizability>
For each of the curable compositions of Examples 1 to 5 and Comparative Examples 1 to 3, the polymerizability of the monomer was evaluated as follows.
Using a DSC manufactured by RETSCH, the curable composition immediately after mixing was filled into an aluminum pan, and the temperature inside the aluminum pan was quickly adjusted to 37.0° C., and the temperature of the curable composition was measured over time.
At this time, the maximum temperature (maximum value of the peak) of the curable composition and the time taken to reach the maximum temperature were measured. The results are shown in Table 1.
The "polymerizable" temperature (°C) shown in Table 1 means the maximum value of the temperature peak of the curable composition. The higher the maximum value of the temperature peak, the more excellent the polymerizability of the monomer in the curable composition.
The "polymerization time (min)" shown in Table 1 means the time at which the maximum value of the temperature peak was obtained. The shorter the time at which the maximum value of the temperature peak was obtained, the more excellent the polymerizability of the monomer in the curable composition.
"Not polymerizable" in Table 1 means that the temperature of the curable composition is below 37.1°C after 5 minutes of polymerization time.

As shown in Table 1, the examples using a polymerization initiator containing a heterocyclic compound containing a mercapto group and a monocyclic heterocycle had excellent monomer polymerization properties because the curing time was short and the temperature was high.
Among them, Examples 1 and 5 in which the monocyclic heterocycle was 1,2,4-triazole were more excellent in polymerizability.
On the other hand, in Comparative Examples 1 to 3, in which a polymerization initiator containing no mercapto group was used, no polymerization occurred.

Claims (10)

A first agent containing a monomer (A);
A second agent containing a monomer (B),
a polymerization initiator, a transition metal compound, and a peroxide, the polymerization initiator and the transition metal compound being contained in the first agent and the peroxide being contained in the second agent , the polymerization initiator and the transition metal compound being contained in the first agent, and the peroxide being contained in the second agent . The kit for preparing a curable composition according to claim 1 , wherein the monomer (A) is a monomer containing no acidic group. The kit for preparing a curable composition according to claim 1 , wherein the monomer (B) includes an acidic group-containing monomer. The kit for preparing a curable composition according to claim 1 , wherein the transition metal compound includes at least one of a copper compound and a vanadium compound. The kit for preparing a curable composition according to claim 1 , wherein the peroxide comprises an organic peroxide. The kit for preparing a curable composition according to claim 1 , wherein the content of the heterocyclic compound relative to the total mass of the first agent and the second agent is 0.01% by mass to 5.0% by mass. The kit for preparing a hardenable composition according to any one of claims 1 to 6, which is used as a dental material. A curable composition comprising: a polymerization initiator comprising a heterocyclic compound containing a mercapto group and a monocyclic heterocycle, the monocyclic heterocycle containing a nitrogen atom and being a heteroaromatic ring; a monomer; a transition metal compound; and a peroxide. A cured product of the curable composition according to claim 8 . A dental material comprising the cured product according to claim 9 .