Dental composition and dental molded body

Abstract

This dental composition contains a polymerizable monomer, a polymerization initiator, and a filler, wherein the amount of active oxygen in the polymerization initiator is 7.00-13.00% inclusive.

Description

Dental compositions and dental molded articles

[0001] This disclosure relates to dental compositions and dental molded articles.

[0002] In recent years, the use of CAD / CAM systems has become widespread as a method for fabricating dental prostheses used to replace missing teeth and other missing teeth. In CAD / CAM systems, dental prostheses are designed using a computer, and then fabricated by cutting a dental molded body using an automatically controlled milling machine according to that design.

[0003] Such dental molded articles are formed, for example, by preparing a dental composition containing a polymerizable monomer, a polymerization initiator, and an inorganic filler, and then thermally polymerizing the dental composition under pressure (see, for example, Patent Document 1). Specifically, in the examples of Patent Document 1, a dental composition is disclosed that contains 1,6-bis(methacrylateethyloxycarbonylamino)trimethylhexane (UDMA) and triethylene glycol methacrylate as polymerizable monomers, benzoyl peroxide as a thermal polymerization initiator, and an inorganic filler.

[0004] International Publication No. 2019 / 189698

[0005] However, the dental composition described in Patent Document 1 has a drawback in that cracks may occur depending on the conditions of pressurized thermal polymerization when forming a dental molded article.

[0006] This disclosure provides dental compositions and dental molded articles that can suppress the occurrence of cracks.

[0007] This disclosure [1] includes a dental composition comprising a polymerizable monomer, a polymerization initiator, and a filler, wherein the amount of active oxygen in the polymerization initiator is 7.00% or more and 13.00% or less.

[0008] This disclosure [2] includes the dental composition described in [1] above, wherein the polymerization initiator has a 10-hour half-life temperature of 70°C or higher and 150°C or lower.

[0009] The present disclosure [3] includes the dental composition described in [1] or [2] above, wherein the polymerizable monomer comprises a first polymerizable monomer having a urethane bond and a thiourethane bond.

[0010] This disclosure [4] includes the dental composition described in [3] above, wherein the first polymerizable monomer further comprises an aromatic ring.

[0011] The present disclosure [5] includes a dental composition according to any one of the above [1] to [4], wherein the polymerizable monomer comprises a second polymerizable monomer that does not have a urethane bond.

[0012] The present disclosure [6] includes a dental composition according to any one of the above [1] to [5], wherein the filler comprises a first filler and a second filler having different particle sizes.

[0013] The present disclosure [7] includes the dental composition described in [6] above, wherein the ratio of the particle size of the second filler to the particle size of the first filler is 1.5 or more and 6.0 or less.

[0014] The present disclosure [8] includes the dental composition described in [6] or [7] above, wherein the ratio of the amount of the second filler to the amount of the first filler is 0.3 or more and 3.5 or less.

[0015] This disclosure [9] includes the dental composition according to any one of the above [1] to [8], wherein the content of the filler in the dental composition is 85.0% by mass or less.

[0016] This disclosure

[10] includes a dental composition according to any one of the above [1] to [9], wherein the polymerization initiator comprises an amyl peroxide compound.

[0017] This disclosure

[11] includes a dental molded article which is a cured product of a dental composition described in any one of paragraphs [1] to

[10] above.

[0018] The dental composition disclosed herein comprises a polymerizable monomer, a polymerization initiator, and a filler, wherein the amount of reactive oxygen species in the polymerization initiator is 7.00% or more and 13.00% or less. Therefore, the occurrence of cracks can be suppressed.

[0019] Furthermore, the dental molded articles of this disclosure contain the above-mentioned dental composition. Therefore, the occurrence of cracks can be suppressed.

[0020] 1. Dental Composition An embodiment of the dental composition of this disclosure will be described. The dental composition is, for example, a material for forming dental molded articles used in dental treatment. Specifically, the dental composition forms dental molded articles used in CAD / CAM systems.

[0021] The dental composition comprises a polymerizable composition and a filler. The dental composition may also contain additives as needed. The polymerizable composition comprises a polymerizable monomer and a polymerization initiator. In other words, the dental composition comprises a polymerizable monomer, a polymerization initiator, and a filler. The dental composition may consist of a polymerizable monomer, a polymerization initiator, and a filler.

[0022] In the following description, (meth)acrylate includes acrylate and / or methacrylate. Also, (meth)acryloyl includes methacryloyl and / or acryloyl. Furthermore, isocyanate group means isocyanate group (-NCO) or isothiocyanate group (-NCS), and isocyanate compound means isocyanate compound or isothiocyanate compound.

[0023] 1.1. Polymerizable Monomers Polymerizable monomers have polymerizable groups. Polymerizable groups include ethylenically unsaturated double bonds. In other words, polymerizable groups are ethylenically unsaturated groups. Examples of polymerizable groups include (meth)acryloyloxy groups, (meth)acryloylamide groups, vinyl groups, and vinyl cyanide groups. Preferably, (meth)acryloyloxy groups are used.

[0024] The polymerizable monomer includes, for example, a first polymerizable monomer and a second polymerizable monomer.

[0025] [First Polymerizable Monomer] The first polymerizable monomer is a polymerizable monomer having the above-mentioned polymerizable group. Preferably, it has an ethylenically unsaturated group. More preferably, it has a (meth)acryloyloxy group.

[0026] Furthermore, the first polymerizable monomer has, for example, a urethane bond and / or a thiourethane bond. Preferably, it has a urethane bond and a thiourethane bond.

[0027] If the first polymerizable monomer has urethane bonds and thiourethane bonds, the flexural strength of dental molded articles can be improved.

[0028] Examples of first polymerizable monomers include reaction products (first (meth)acrylate compounds) of thiol compounds, isocyanate compounds, and hydroxy(meth)acrylate compounds. As will be explained in more detail later, thiol compounds have two or more mercapto groups, isocyanate compounds have two or more isocyanate groups, and hydroxy(meth)acrylate compounds are (meth)acrylate compounds having one or more hydroxyl groups.

[0029] In other words, the first polymerizable monomer is, for example, a reaction product (first (meth)acrylate compound) of a thiol compound having two or more mercapto groups, an isocyanate compound having two or more isocyanate groups, and a (meth)acrylate compound having one or more hydroxyl groups (hydroxy(meth)acrylate compound). Preferably, a reaction product (first (meth)acrylate compound) of a thiol compound having three or four mercapto groups, an isocyanate compound having two isocyanate groups, and a hydroxy(meth)acrylate compound having one hydroxyl group is included.

[0030] The first polymerizable monomer preferably contains a first (meth)acrylate compound. The first polymerizable monomer may also contain a first (meth)acrylate compound and a polymerizable compound having a urethane bond, as described later. The first polymerizable monomer more preferably consists of a first (meth)acrylate compound. When the first polymerizable monomer contains a first (meth)acrylate compound, the content of the first (meth)acrylate compound in the first polymerizable monomer is, for example, 60% by mass or more, preferably 80% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, and particularly preferably 100% by mass.

[0031] If the first polymerizable monomer contains a first (meth)acrylate compound, the flexural strength of the dental molded article can be improved. Furthermore, if the content of the first (meth)acrylate compound in the first polymerizable monomer is above the lower limit mentioned above, the flexural strength of the dental molded article can be further improved.

[0032] The first (meth)acrylate compound is thiourethane (meth)acrylate when an isocyanate group is used as the isocyanate compound. Furthermore, the first polymerizable monomer is a (meth)acrylate having a structure in which the C=O group constituting the thiourethane in the thiourethane (meth)acrylate is replaced with C=S when an isocyanate group is used as the isocyanate compound.

[0033] The first (meth)acrylate compound is preferably a thiourethane (meth)acrylate, from the viewpoint of mechanical properties, in which a compound having an isocyanate group is used as the isocyanate compound.

[0034] The first (meth)acrylate compound may or may not have mercapto groups. Specifically, in the reaction between the thiol compound, the iso(thio)cyanate compound, and the hydroxy(meth)acrylate compound, all of the mercapto groups of the thiol compound may react, or some of the mercapto groups of the thiol compound may not react. In this case, a mixture of the first (meth)acrylate compound and the unreacted thiol compound may be produced.

[0035] The first (meth)acrylate compound may or may not have isocyanate groups. Specifically, in the reaction between the thiol compound, the isocyanate compound, and the hydroxy(meth)acrylate, all of the isocyanate groups of the isocyanate compound may react, or some of the isocyanate groups of the isocyanate compound may not react. In this case, a mixture of the first (meth)acrylate compound and unreacted isocyanate compound may be produced.

[0036] The first (meth)acrylate compound has a mercapto group and / or an iso(thio)cyanate group, and may also have a hydroxyl group. Specifically, in the reaction between the thiol compound, the iso(thio)cyanate compound, and the hydroxy(meth)acrylate, some of the hydroxyl groups of the hydroxy(meth)acrylate compound may not react. In this case, a mixture of the first (meth)acrylate compound and the unreacted hydroxy(meth)acrylate compound may be formed.

[0037] The presence or absence of mercapto groups, iso(thio)cyanate groups, and (meth)acryloyloxy groups can be confirmed, for example, by FT-IR measurement.

[0038] The first (meth)acrylate compound preferably has a structure represented by the following general formula (1) and / or a structure represented by the following general formula (2). More preferably, it has a structure represented by the following general formula (1) and a structure represented by the following general formula (2).

[0039]

[0040]

[0041] In the above general formulas (1) and (2), R １ and R ２ each represent an oxygen atom or a sulfur atom, and * represents a bond. R １ and R ２ are each preferably an oxygen atom.

[0042] When R １ and R ２ are each an oxygen atom, general formula (1) represents a thiourethane bond, and general formula (2) represents a urethane bond. In other words, the first polymerizable monomer preferably has a thiourethane bond and / or a urethane bond. More preferably, it has a thiourethane bond and a urethane bond.

[0043] The structure represented by general formula (1) is formed by the reaction between a mercapto group contained in a thiol compound and an iso(thio)cyanate group contained in an iso(thio)cyanate compound. The structure represented by general formula (2) is usually formed by the reaction between an iso(thio)cyanate group contained in an iso(thio)cyanate compound and a hydroxy group contained in a hydroxy(meth)acrylate compound.

[0044] Examples of the first (meth)acrylate include compounds represented by the following general formula (3).

[0045]

[0046] In the above general formula (3), R １ and R ２ each represent an oxygen atom or a sulfur atom, and preferably represent an oxygen atom. R ３ represents a residue obtained by removing all mercapto groups from a thiol compound. R ４ represents a residue obtained by removing all iso(thio)cyanate groups from an iso(thio)cyanate compound. R ５ represents a residue obtained by removing one (meth)acryloyloxy group and one hydroxy group from a hydroxy(meth)acrylate compound. R ６represents a hydrogen atom or a methyl group. n represents the total number of mercapto groups contained in the thiol compound. Note that R １ and R ２ Each of these is equivalent to the same symbol in general formulas (1) and (2).

[0047] Note that there are multiple R １ , R ２ , R ４ ~R ６ Each of them may be the same or different.

[0048] R ３ For example, a trivalent or tetravalent hydrocarbon group having 6 to 20 carbon atoms, having at least one selected from the group consisting of sulfide bonds and ester bonds in the hydrocarbon group. ３ The molecular weight is, for example, 150 to 400.

[0049] Examples of trivalent or tetravalent hydrocarbon groups having 6 to 20 carbon atoms include the trimethylolpropanetris(propionate) group, the pentaerythritoltetrakis(acetate) group, the pentaerythritoltetrakis(propionate) group, the 5-ethyl-4,7-dithiaoctyl group, and the 6,8-diethyl-4,7,10-trithiatridecyl group.

[0050] R ３ For example, it is one selected from the group consisting of the following formulas (4) to (8). Preferably, it is one selected from the group consisting of the following formulas (6) to (8).

[0051]

[0052] R ４ For example, a divalent hydrocarbon group selected from the group consisting of a divalent aromatic hydrocarbon group having 6 to 12 carbon atoms, a divalent chain hydrocarbon group having 5 to 12 carbon atoms, and a divalent alicyclic hydrocarbon group having 5 to 12 carbon atoms, wherein both ends of the divalent group are CX ２ It is a group formed by the bonding of two groups.

[0053] R ４ The number of carbon atoms in the divalent aromatic hydrocarbon group, divalent chain hydrocarbon group, or divalent alicyclic hydrocarbon group contained in the material is, for example, 5 to 12, preferably 6 to 12, from the viewpoint of having appropriate rigidity. Examples of alicyclic hydrocarbon groups having 5 to 12 carbon atoms include isophorone group, cyclohexylmethylene group, and bicyclo[2.2.1]heptylene group. Preferably, from the viewpoint of flexural strength of dental molded articles, bicyclo[2.2.1]heptylene group is preferred. Examples of chain hydrocarbon groups having 5 to 12 carbon atoms include pentamethylene group, hexamethylene group, and trimethylhexamethylene group. Preferably, from the viewpoint of flexural strength of dental molded articles, trimethylhexamethylene group is preferred. Examples of aromatic hydrocarbon groups having 6 to 12 carbon atoms include phenylene group.

[0054] R ４ Preferably, a divalent aromatic hydrocarbon group having 6 to 12 carbon atoms, with CX at both ends of the divalent portion. ２ It is a group to which a group is bonded. More preferably, in a phenylene group, CX is bonded to both ends of the divalent group. ２ It is a group to which a group is bonded. In other words, the first polymerizable monomer preferably has an aromatic ring.

[0055] If the first polymerizable monomer has an aromatic ring, the flexural strength of the dental molded product can be improved.

[0056] In the above general formula (1), R ４ In CX ２ Each group is bonded to the nitrogen atom of the adjacent NH group. Examples of X include a hydrogen atom and an alkyl group having 1 to 3 carbon atoms. Note that each of the multiple X groups may be the same or different.

[0057] CX ２ As a base, for example, CH where each of the two X atoms is a hydrogen atom. ２ C(CH) is a methylene group, and each of the two X's is a methyl group. ３ ) ２ The basis is cited.

[0058] R ４Two CX included ２ When the group to which the group is bonded is an aromatic hydrocarbon group, two CXs are attached to the benzene ring contained in that aromatic hydrocarbon group. ２ The relative positions of the groups may be ortho, meta, or para. Preferably, they are in the meta or para position. More preferably, they are in the meta position.

[0059] R ４ Two CX included ２ When the group to which the group is bonded is an alicyclic hydrocarbon group, two CXs are attached to the carbon ring contained in that alicyclic hydrocarbon group. ２ The relative positions of the bases are not particularly limited. These two CX ２ The group is preferably not bonded to the same carbon atom of the carbocyclic. More preferably, one CX ２ For carbon atoms on a carbocyclic ring to which the group is bonded, and for carbon atoms on carbocyclic rings two or more distance away, the other CX ２ The groups bond together.

[0060] Note that the two CX ２ Positional isomers with different group positions may be used individually or in combination of two or more.

[0061] R ４ For example, it is one group selected from the group consisting of the following formulas (9) to (12). In the case of the group of formula (9), it is generally a mixture of positional isomers in which methylene groups are bonded at the 2,5 position and the 2,6 position.

[0062]

[0063] R ５ For example, R is a linear alkylene group having 2 to 6 carbon atoms, in which case the hydrogen atoms may be substituted with an alkyl group having 1 to 3 carbon atoms or a (meth)acryloyloxymethylene group. ５This is, for example, a linear oxyalkylene group in which the hydrogen atoms may be substituted with an alkyl group having 1 to 3 carbon atoms or a (meth)acryloyloxymethylene group. Preferably, it is a linear alkylene group having 2 to 6 carbon atoms (more preferably 2 to 4 carbon atoms) in which the hydrogen atoms may be substituted with an alkyl group having 1 to 3 carbon atoms, or a linear oxyalkylene group in which the hydrogen atoms may be substituted with an alkyl group having 1 to 3 carbon atoms.

[0064] Examples of linear alkylene groups include -CH ２ CH ２ -ien-CH ２ CH ２ CH ２ -ien-CH ２ CH ２ CH ２ CH ２ -ien-CH ２ CH ２ CH ２ CH ２ CH ２ -, and -CH ２ CH ２ CH ２ CH ２ CH ２ CH ２ - is one example. Preferably, -CH ２ CH ２ -ien-CH ２ CH ２ CH ２ -, and -CH ２ CH ２ CH ２ CH ２ - is one example.

[0065] Examples of linear oxyalkylene groups include -CH ２ CH ２ OCH ２ CH ２ -, and -CH ２ CH ２ OCH ２ CH ２ OCH ２ CH ２ - is one example. Preferably, -CH ２ CH ２ OCH ２ CH ２-, which may be mentioned.

[0066] From the viewpoint of imparting appropriate flexibility to the first (meth)acrylate, the number of carbon atoms in the linear alkylene group and linear oxyalkylene group is, for example, 2 to 6, preferably 2 to 4, more preferably 2.

[0067] Examples of the alkyl group substitutable for a hydrogen atom contained in a linear alkylene group and a linear oxyalkylene group include CH ３ -, CH ３ CH ２ -, CH ３ CH ２ CH ２ -, and (CH ３ ) ２ CH-, which may be mentioned. From the viewpoint of imparting appropriate flexibility to the first (meth)acrylate, the number of carbon atoms in the alkyl group is, for example, 1 to 3, preferably 1 to 2, more preferably 1.

[0068] Examples of the (meth)acryloyloxymethylene group substitutable for a hydrogen atom contained in a linear alkylene group and a linear oxyalkylene group include a methacryloyloxymethylene group and an acryloyloxymethylene group.

[0069] R ５ The substituent of preferably substitutes for a hydrogen bonded to a carbon adjacent to a carbon of the linear alkylene group or linear oxyalkylene group adjacent to the (meth)acryloyl groups at both ends contained in the first (meth)acrylate.

[0070] R ５ The number of substituents (alkyl groups substitutable for hydrogen atoms and (meth)acryloyloxymethylene groups substitutable for hydrogen atoms) is not particularly limited. R ５ From the viewpoint of imparting appropriate flexibility to the first (meth)acrylate, the number of substituents for each R ５ is 0 to 8, preferably 0 to 4, more preferably 0 to 2, still more preferably 0 (that is, no substituent for R ５ ).

[0071] R ６This represents, for example, a hydrogen atom or a methyl group. From the viewpoint of the flexural strength of dental molded articles, a hydrogen atom is preferred.

[0072] From the viewpoint of the flexural strength of dental molded articles, the first (meth)acrylate preferably contains relatively few methacryloyl groups and relatively many acryloyl groups as polymerizable groups. More preferably, it contains only acryloyl groups as polymerizable groups (R ６ is a hydrogen atom, and R ５ The (meth)acryloyloxymethylene group that it may possess is an acryloyloxymethylene group.

[0073] R １ and R ２ Each of these represents either an oxygen atom or a sulfur atom. From the viewpoint of mechanical properties, an oxygen atom is preferred. １ and R ２ If each of them is an oxygen atom, the first (meth)acrylate is thiourethane (meth)acrylate. １ and R ２ In some cases, the first (meth)acrylate is referred to as a thiourethane-type (meth)acrylate when each of the atoms is either an oxygen atom or a sulfur atom.

[0074] If the first polymerizable monomer of this disclosure contains a first (meth)acrylate which is a thiourethane-type (meth)acrylate, the dental molded article will possess both toughness and rigidity.

[0075] (Thiol Compounds) Thiol compounds have two or more mercapto groups. The number of mercapto groups in a thiol compound is, for example, two or more, preferably three or more, and more preferably three or four. In other words, thiol compounds are more preferably thiol compounds having three or four mercapto groups.

[0076] Thiol compounds include, for example, R ３ - (SH) ｎ It is represented by R ３ Each of n and n is equivalent to the same symbol in general formula (3).

[0077] Examples of thiol compounds include aliphatic polythiol compounds, aromatic polythiol compounds, and heterocyclic polythiol compounds.

[0078] Specifically, aliphatic polythiol compounds having three or more mercapto groups include, for example, 1,2,3-propanetrithiol, tetrakis(mercaptomethyl)methane, trimethylolpropanetris(2-mercaptoacetate), trimethylolpropanetris(3-mercaptopropionate), trimethylolethanetris(2-mercaptoacetate), trimethylolethanetris(3-mercaptopropionate), pentaerythritoltetrakis(2-mercaptoacetate), pentaerythritoltetrakis(3-mercaptopropionate), 1,2,3-tris(mercaptomethylthio)propane, 1,2,3-tris(2-mercaptoethylthio)propane, and 1,2,3-tris(3 Examples include mercaptopropylthio)propane, 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane, 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,8-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, tetrakis(mercaptomethylthiomethyl)methane, tetrakis(2-mercaptoethylthiomethyl)methane, tetrakis(3-mercaptopropylthiomethyl)methane, bis(2,3-dimercaptopropyl)sulfide, and esters of these thioglycolic acid and mercaptopropionic acid. Furthermore, aliphatic polythiol compounds having three or more mercapto groups include, for example, 1,1,3,3-tetrakis(mercaptomethylthio)propane, 1,1,2,2-tetrakis(mercaptomethylthio)ethane, tris(mercaptomethylthio)methane, and tris(mercaptoethylthio)methane.

[0079] Examples of aromatic polythiol compounds having three or more mercapto groups include 1,3,5-trimercaptobenzene, 1,3,5-tris(mercaptomethyl)benzene, 1,3,5-tris(mercaptomethyleneoxy)benzene, and 1,3,5-tris(mercaptoethyleneoxy)benzene.

[0080] Examples of heterocyclic polythiol compounds having three or more mercapto groups include 2,4,6-trimercapto-s-triazine and 2,4,6-trimercapto-1,3,5-triazine.

[0081] Examples of aliphatic polythiol compounds having two mercapto groups include methanedithiol, 1,2-ethanedithiol, 1,2-cyclohexanedithiol, bis(2-mercaptoethyl) ether, diethylene glycol bis(2-mercaptoacetate), diethylene glycol bis(3-mercaptopropionate), ethylene glycol bis(2-mercaptoacetate), ethylene glycol bis(3-mercaptopropionate), bis(mercaptomethyl) sulfide, bis(mercaptomethyl) disulfide, bis(mercaptoethyl) sulfide, and bis(mercaptoethyl) disulfide. Examples include phyto, bis(mercaptopropyl) sulfide, bis(mercaptomethylthio)methane, bis(2-mercaptoethylthio)methane, bis(3-mercaptopropylthio)methane, 1,2-bis(mercaptomethylthio)ethane, 1,2-bis(2-mercaptoethylthio)ethane, 1,2-bis(3-mercaptopropylthio)ethane, 2,5-dimercaptomethyl-1,4-dithiane, 2,5-dimercapto-1,4-dithiane, 2,5-dimercaptomethyl-2,5-dimethyl-1,4-dithiane, and esters of these thioglycolic acid and mercaptopropionic acid.Furthermore, aliphatic polythiol compounds having two mercapto groups include, for example, bis(2-mercaptoethyl) sulfide, hydroxymethyl sulfide bis(2-mercaptoacetate), hydroxymethyl sulfide bis(3-mercaptopropionate), hydroxyethyl sulfide bis(2-mercaptoacetate), hydroxyethyl sulfide bis(3-mercaptopropionate), hydroxymethyl disulfide bis(2-mercaptoacetate), hydroxymethyl disulfide bis(3-mercaptopropionate), and hydroxyethyl disulfide bis(2 Examples include mercaptoacetate, hydroxyethyl disulfide bis(3-mercaptopropineauto), 2-mercaptoethyl ether bis(2-mercaptoacetate), 2-mercaptoethyl ether bis(3-mercaptopropionate), thiodiglycolate bis(2-mercaptoethyl ester), thiodipropionate bis(2-mercaptoethyl ester), dithiodiglycolate bis(2-mercaptoethyl ester), dithiodipropionate bis(2-mercaptoethyl ester), and 4,6-bis(mercaptomethylthio)-1,3-dithiane.

[0082] Examples of aromatic polythiol compounds having two mercapto groups include 1,2-dimercaptobenzene, 1,3-dimercaptobenzene, 1,4-dimercaptobenzene, 1,2-bis(mercaptomethyl)benzene, 1,3-bis(mercaptomethyl)benzene, 1,4-bis(mercaptomethyl)benzene, 1,2-bis(mercaptoethyl)benzene, 1,3-bis(mercaptoethyl)benzene, 1,4-bis(mercaptoethyl)benzene, 2,5-toluenedithiol, 3,4-toluenedithiol, 1,5-naphthalenedithiol, and 2,6-naphthalenedithiol.

[0083] Examples of heterocyclic polythiol compounds having two mercapto groups include 2-methylamino-4,6-dithiol-sym-triazine, 3,4-thiophenedithiol, bismuthiol, 4,6-bis(mercaptomethylthio)-1,3-dithiane, and 2-(2,2-bis(mercaptomethylthio)ethyl)-1,3-dithiethane.

[0084] Thiol compounds may be used individually or in combination of two or more.

[0085] Preferably, the thiol compound is at least one selected from the group consisting of trimethylolpropane tris(3-mercaptopropionate), pentaerythritol tetrakis(2-mercaptoacetate), pentaerythritol tetrakis(3-mercaptopropionate), 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane, 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,8-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, and 1,1,3,3-tetrakis(mercaptomethylthio)propane. More preferably, it is at least one selected from the group consisting of pentaerythritol tetrakis(3-mercaptopropionate), 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane, 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, and 4,8-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane.

[0086] (Iso(thio)cyanate compounds) Iso(thio)cyanate compounds have two or more iso(thio)cyanate groups. Preferably, they have two iso(thio)cyanate groups.

[0087] Iso(thio)cyanate compounds include, for example, (NCR １ )-R ４ - (NCR２ ) is represented by R １ , R ２ , and, R ４ Each of these is equivalent to the same symbol in general formula (3).

[0088] Examples of iso(thio)cyanate compounds include aliphatic polyisocyanate compounds, alicyclic polyisocyanate compounds, aromatic polyisocyanate compounds, heterocyclic polyisocyanate compounds, aliphatic polyisothiocyanate compounds, alicyclic polyisothiocyanate compounds, aromatic polyisothiocyanate compounds, sulfur-containing heterocyclic polyisothiocyanate compounds, and modified versions thereof.

[0089] Specifically, aliphatic polyisocyanate compounds include, for example, pentamethylene diisocyanate, hexamethylene diisocyanate, 2,2,4-trimethylhexane diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, lysine diisocyanate methyl ester, lysine triisocyanate, m-xylylene diisocyanate, p-xylylene diisocyanate, α,α,α′,α′-tetramethylxylylene diisocyanate, and Examples include bis(isocyanate-methyl)naphthalene, methylisocyanate, bis(isocyanate-methyl)sulfide, bis(isocyanate-ethyl)sulfide, bis(isocyanate-methyl)disulfide, bis(isocyanate-ethyl)disulfide, bis(isocyanate-methylthio)methane, bis(isocyanate-ethylthio)methane, bis(isocyanate-ethylthio)ethane, and bis(isocyanate-methylthio)ethane.

[0090] Examples of alicyclic polyisocyanate compounds include isophorone diisocyanate, bis(isocyanate methyl)cyclohexane, dicyclohexylmethane-4,4'-diisocyanate, cyclohexane diisocyanate, methylcyclohexane diisocyanate, dicyclohexyldimethylmethane isocyanate, 2,5-bis(isocyanate methyl)bicyclo-[2.2.1]-heptane, 2,6-bis(isocyanate methyl)bicyclo-[2.2.1]-heptane, 3,8-bis(isocyanate methyl)tricyclodecane, 3,9-bis(isocyanate methyl)tricyclodecane, 4,8-bis(isocyanate methyl)tricyclodecane, and 4,9-bis(isocyanate methyl)tricyclodecane.

[0091] Examples of aromatic polyisocyanate compounds include phenylenediisocyanate, 2,4-tolylenediisocyanate, 2,6-tolylenediisocyanate, 4,4'-diphenylmethanediisocyanate, and diphenyl sulfide-4,4-diisocyanate.

[0092] Examples of heterocyclic polyisocyanate compounds include 2,5-diisocyanatethiophene, 2,5-bis(isocyanatemethyl)thiophene, 2,5-diisocyanatetetrahydrothiophene, 2,5-bis(isocyanatemethyl)tetrahydrothiophene, 3,4-bis(isocyanatemethyl)tetrahydrothiophene, 2,5-diisocyanate-1,4-dithiane, 2,5-bis(isocyanatemethyl)-1,4-dithiane, 4,5-diisocyanate-1,3-dithiolane, and 4,5-bis(isocyanatemethyl)-1,3-dithiolane.

[0093] Examples of aliphatic polyisothiocyanate compounds include hexamethylene diisothiocyanate, lysine diisothiocyanate methyl ester, lysine triisothiocyanate, m-xylylene diisothiocyanate, bis(isothiocyanate methyl) sulfide, bis(isothiocyanate ethyl) sulfide, and bis(isothiocyanate ethyl) disulfide.

[0094] Examples of alicyclic polyisothiocyanate compounds include isophorone diisothiocyanate, bis(isothiocyanate methyl)cyclohexane, dicyclohexylmethane diisothiocyanate, cyclohexane diisothiocyanate, methylcyclohexane diisothiocyanate, 2,5-bis(isothiocyanate methyl)bicyclo-[2.2.1]-heptane, 2,6-bis(isothiocyanate methyl)bicyclo-[2.2.1]-heptane, 3,8-bis(isothiocyanate methyl)tricyclodecane, 3,9-bis(isothiocyanate methyl)tricyclodecane, 4,8-bis(isothiocyanate methyl)tricyclodecane, and 4,9-bis(isothiocyanate methyl)tricyclodecane.

[0095] Examples of aromatic polyisothiocyanate compounds include tolylene diisothiocyanate, 4,4-diphenylmethane diisothiocyanate, and diphenyl disulfide-4,4-diisothiocyanate.

[0096] Examples of sulfur-containing heterocyclic polyisothiocyanate compounds include 2,5-diisothiocyanate thiophene, 2,5-bis(isothiocyanate methyl)thiophene, 2,5-isothiocyanate tetrahydrothiophene, 2,5-bis(isothiocyanate methyl)tetrahydrothiophene, 3,4-bis(isothiocyanate methyl)tetrahydrothiophene, 2,5-diisothiocyanate 1,4-dithiane, 2,5-bis(isothiocyanate methyl)-1,4-dithiane, 4,5-diisothiocyanate 1,3-dithiolane, and 4,5-bis(isothiocyanate methyl)-1,3-dithiolane.

[0097] Furthermore, examples of iso(thio)cyanate compounds include chlorine-substituted, halogen-substituted (e.g., bromine-substituted), alkyl-substituted, alkoxy-substituted, nitro-substituted, prepolymer-type modified compounds with polyhydric alcohols, carbodiimide-substituted, urea-substituted, biuret-substituted, and dimerization or trimmerization reaction products of the above compounds.

[0098] Preferred isocyanate compounds include hexamethylene diisocyanate, 2,2,4-trimethylhexane diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, pentamethylene diisocyanate, m-xylylene diisocyanate, isophorone diisocyanate, bis(isocyanate methyl)cyclohexane, bis(isocyanate cyclohexyl)methane, 2,5-bis(isocyanate methyl)bicyclo-[2.2.1]-heptane, 2,6-bis(isocyanate methyl)bicyclo-[2.2.1]-heptane, tolylene diisocyanate, phenylene diisocyanate, and 4,4'-diphenylmethane diisocyanate. More preferably, examples include 2,2,4-trimethylhexanediisocyanate, 2,4,4-trimethylhexamethylenediisocyanate, m-xylylenediisocyanate, bis(isocyanatemethyl)cyclohexane, bis(isocyanatecyclohexyl)methane, 2,5-bis(isocyanatemethyl)bicyclo-[2.2.1]-heptane, and 2,6-bis(isocyanatemethyl)bicyclo-[2.2.1]-heptane.

[0099] Iso(thio)cyanate compounds may be used alone or in combination of two or more.

[0100] (Hydroxy(meth)acrylate compounds) Hydroxy(meth)acrylate compounds have one or more hydroxyl groups and one or more polymerizable groups. Preferably, they have one or more hydroxyl groups and one or more (meth)acryloyl groups. From the viewpoint of handling the first (meth)acrylate compound, it is more preferable that it has one hydroxyl group and one (meth)acryloyl group.

[0101] Hydroxy(meth)acrylate compounds include, for example, CH ２ = C(R ６ )-COO-R ５ It is a compound represented by -OH. ５ and R ６ Each of these is equivalent to the same symbol in general formula (3).

[0102] Examples of hydroxyacrylate compounds having one polymerizable group and one hydroxyl group include 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxybutyl acrylate, 2-hydroxy-3-phenoxypropyl acrylate, 4-hydroxybutyl acrylate, and 1,4-cyclohexanedimethanol monoacrylate.

[0103] Examples of hydroxymethacrylate compounds having one polymerizable group and one hydroxyl group include 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2-hydroxybutyl methacrylate, 2-hydroxy-3-phenoxypropyl methacrylate, 4-hydroxybutyl methacrylate, and 1,4-cyclohexanedimethanol monomethacrylate.

[0104] Hydroxy(meth)acrylate compounds may be used alone or in combination of two or more.

[0105] (Meth)method for producing the first (meth)acrylate) The first (meth)acrylate is obtained by reacting a thiol compound with an isocyanate compound and a hydroxy(meth)acrylate compound, as described above. The reaction method is not particularly limited and may include known or similar methods.

[0106] Examples of methods for producing the first (meth)acrylate include adding a mixture of a thiol compound and a hydroxy(meth)acrylate compound to an isocyanate compound in a reaction vessel while controlling the amount added and mixing them; adding a thiol compound to an isocyanate compound in a reaction vessel while controlling the amount added and mixing them to produce an intermediate, and then adding a hydroxy(meth)acrylate compound to this intermediate while controlling the amount added and mixing them; and simultaneously adding a thiol compound, an isocyanate compound, and a hydroxy(meth)acrylate compound to a reaction vessel while controlling the amounts added and mixing them.

[0107] As described above, producing the first (meth)acrylate by miscion allows for the control of the amount of heat generated by the reaction between the mercapto group and the iso(thio)cyanate group, and the reaction between the hydroxyl group and the iso(thio)cyanate group, within an appropriate range, thus facilitating temperature control during the reaction.

[0108] As a method for producing the first (meth)acrylate, from the viewpoint of the reactivity of the raw materials and the pot life of the obtained first (meth)acrylate, a preferred method is one that involves an intermediate, that is, a method in which a thiol compound and an isocyanate compound are reacted to obtain an intermediate, and then a hydroxy(meth)acrylate compound is mixed with this intermediate.

[0109] Furthermore, a catalyst, polymerization inhibitor, and solvent may be added in the production of the first (meth)acrylate. The catalyst can improve the reaction rate. The polymerization inhibitor can suppress unintended polymerization and excessive polymerization in the production of the first (meth)acrylate.

[0110] Examples of catalysts include organotin compounds, tin halide compounds, other organometallic compounds other than tin, trialkylphosphine compounds, and amine compounds and their salts. Examples of organotin compounds include dibutyltin dilaurate, dibutyltin dioctate, and tin octanoate. Examples of tin halide compounds include dibutyltin dichloride and dimethyltin dichloride. Examples of other organometallic compounds other than tin include copper naphthenate, cobalt naphthenate, zinc naphthenate, acetylacetonatozirconium, acetylacetonatoiron, and acetylacetonatogermanium. Examples of amine compounds include triethylamine, 1,4-diazabicyclo[2.2.2]octane, 2,6,7-trimethyl-1-diazabicyclo[2.2.2]octane, 1,8-diazabicyclo[5.4.0]undecene, N,N-dimethylcyclohexylamine, pyridine, N-methylmorpholine, N,N,N',N'-tetramethylethylenediamine, N,N,N',N'-tetramethyl-1,3-butanediamine, N,N,N',N'-pentamethyldiethylenetriamine, N,N,N',N'-tetra(3-dimethylaminopropyl)-methanediamine, N,N'-dimethylpiperazine, and 1,2-dimethylimidazole. Examples of trialkylphosphine compounds include tri-n-butylphosphine, tri-n-hexylphosphine, tricyclohexylphosphine, and tri-n-octylphosphine.

[0111] The amount of catalyst added per 100 parts by mass of the total amount of the thiol compound, iso(thio)cyanate compound, and hydroxy(meth)acrylate compound is, for example, 0.001 to 0.5 parts by mass, preferably 0.002 to 0.3 parts by mass, more preferably 0.01 to 0.2 parts by mass, and even more preferably 0.05 to 0.2 parts by mass.

[0112] Examples of polymerization inhibitors include known polymerization inhibitors that can suppress the reaction of acrylate groups. Examples of polymerization inhibitors include dibutylhydroxytoluene (BHT), hydroquinone (HQ), hydroquinone monomethyl ether (MEHQ), 4-methoxyphenol, and phenothiazine (PTZ).

[0113] The amount of polymerization inhibitor added per 100 parts by mass of the total amount of thiol compound, iso(thio)cyanate compound, and hydroxy(meth)acrylate compound is, for example, 0.001 to 0.5 parts by mass, preferably 0.002 to 0.3 parts by mass, more preferably 0.005 to 0.3 parts by mass, even more preferably 0.005 to 0.1 parts by mass, and most preferably 0.01 to 0.1 parts by mass.

[0114] The solvent is not particularly limited, as long as it does not have practical reactivity with the thiol compound, iso(thio)cyanate compound, and hydroxy(meth)acrylate compound, does not inhibit the reaction, and dissolves the starting materials and products. Alternatively, the reaction may be carried out without a solvent. Since thiol compounds and hydroxy(meth)acrylate compounds are usually low-viscosity liquids, they are miscible with iso(thio)cyanate compounds and can be reacted without a solvent.

[0115] The ratio (a / b) of the number of moles of mercapto groups in the thiol compound to the number of moles of iso(thio)cyanate groups in the iso(thio)cyanate compound (b) is, for example, 0.01 to 0.20, preferably 0.01 to 0.18.

[0116] The ratio ((a+c) / b) of the total number of moles (a) of mercapto groups in a thiol compound and hydroxyl groups in a hydroxy(meth)acrylate compound to the number of moles (b) of iso(thio)cyanate groups in an iso(thio)cyanate compound is, for example, 0.70 to 1.30, preferably 0.70 to 1.20, and more preferably 0.90 to 1.10.

[0117] If the above molar ratio (a / b, and / or (a+c) / b) is within the above range, a first (meth)acrylate can be obtained that provides a dental molded article with excellent heat resistance, solvent resistance, and impact resistance.

[0118] Furthermore, the first (meth)acrylate may be used alone or in combination of two or more types. Specifically, when the first (meth)acrylate is produced using a thiol compound, an iso(thio)cyanate compound, and two or more hydroxyacrylate compounds as raw materials, or when the first (meth)acrylate is produced using a thiol compound, an iso(thio)cyanate compound, a hydroxyacrylate compound, and a hydroxymethacrylate compound as raw materials, the polymerizable composition will contain two or more types of the first (meth)acrylate.

[0119] The obtained first (meth)acrylate is represented by general formula (3) and is preferably a liquid at room temperature. The viscosity of the first (meth)acrylate at 65°C is, for example, 1 mPa·s to 50,000 mPa·s, preferably 1 mPa·s to 20,000 mPa·s, and more preferably 1 mPa·s to 5,000 mPa·s.

[0120] If the viscosity of the first (meth)acrylate at 65°C is within the above range, the viscosity of the polymerizable composition containing the first (meth)acrylate will be low, and the dental composition can be easily prepared. The viscosity at 65°C can be measured at 65°C using, for example, an E-type viscometer (TVE-22H, manufactured by Toki Sangyo Co., Ltd.) (the same applies hereinafter).

[0121] The refractive index of the first (meth)acrylate at 25°C is, for example, 1.40 to 1.70, preferably 1.45 to 1.60.

[0122] If the refractive index of the first (meth)acrylate at 25°C is within the above range, the aesthetics of the dental molded product can be improved. The refractive index at 25°C can be measured at 25°C using, for example, an Abbe-type fully digital refractometer (Abbemat 550, manufactured by Anton Paar) (the same applies hereinafter).

[0123] Furthermore, the first polymerizable monomer is, for example, a liquid at room temperature. The viscosity of the first polymerizable monomer at 65°C is, for example, 1 mPa·s to 50,000 mPa·s, preferably 1 mPa·s to 20,000 mPa·s, and more preferably 1 mPa·s to 5,000 mPa·s. When the first polymerizable monomer consists of a first (meth)acrylate, the viscosity of the first polymerizable monomer at 65°C is the same as the viscosity of the first (meth)acrylate at 65°C.

[0124] If the viscosity of the first polymerizable monomer at 65°C is within the above range, the viscosity of the polymerizable composition containing the first polymerizable monomer will be low, and the dental composition can be easily prepared.

[0125] The refractive index of the first polymerizable monomer at 25°C is, for example, 1.40 to 1.70, preferably 1.45 to 1.60.

[0126] If the refractive index of the first polymerizable monomer at 25°C is within the above range, the aesthetics of the dental molded product can be improved.

[0127] The content of the first polymerizable monomer in the polymerizable composition is, for example, 50% to 100% by mass, preferably 60% to 90% by mass, and more preferably 65% ​​to 80% by mass. Alternatively, the content of the first polymerizable monomer in the polymerizable composition may be, for example, 50% or more by mass, preferably 60% or more by mass, more preferably 65% ​​or more by mass, or, for example, less than 100% by mass, preferably 90% or less by mass, and more preferably 80% or less by mass.

[0128] If the content of the first polymerizable monomer in the polymerizable composition is within the above range, the occurrence of cracks can be suppressed, and the flexural strength of dental molded articles can be improved.

[0129] The content of the first polymerizable monomer in the dental composition is, for example, 1% to 50% by mass, preferably 3% to 40% by mass, and more preferably 5% to 30% by mass. Alternatively, the content of the first polymerizable monomer in the dental composition may be, for example, 1% or more by mass, preferably 3% or more by mass, more preferably 5% or more by mass, or, for example, 50% or less by mass, preferably 40% or less by mass, and more preferably 30% or less by mass.

[0130] If the content of the first polymerizable monomer in the dental composition is within the above range, the occurrence of cracks can be suppressed, and the flexural strength of the dental molded article can be improved.

[0131] [Second Polymerizable Monomer] The second polymerizable monomer is a polymerizable monomer having the polymerizable group described above. Preferably, it has an ethylenically unsaturated group. More preferably, it has a (meth)acryloyloxy group.

[0132] The second polymerizable monomer is different from the first polymerizable monomer. The second polymerizable monomer, for example, does not have urethane bonds. Preferably, it does not have thiourethane bonds and urethane bonds.

[0133] The second polymerizable monomer is a dilution monomer. The second polymerizable monomer suppresses the excessively high content of the first polymerizable monomer in the polymerizable composition. Therefore, the viscosity of the polymerizable composition can be adjusted. Furthermore, when forming dental molded articles by pressure thermal polymerization, the occurrence of cracks can be suppressed, and the elastic modulus of the dental molded article can be adjusted.

[0134] The number of polymerizable groups contained in the second polymerizable monomer may be one or two or more. Preferably, it is 2 to 10, more preferably 2 to 6, even more preferably 2 to 4, and most preferably 2.

[0135] The molecular weight of the second polymerizable monomer is, for example, 80 to 1000, preferably 150 to 700. If the molecular weight of the second polymerizable monomer is above the lower limit, it is possible to suppress excessively low boiling points. Also, if the molecular weight of the second polymerizable monomer is below the upper limit, it is possible to suppress excessively high viscosity. In other words, if the molecular weight of the second polymerizable monomer is within the above range, the operability in preparing the polymerizable composition can be improved.

[0136] The second polymerizable monomer is, for example, a liquid at room temperature. The viscosity of the second polymerizable monomer at 65°C is, for example, 1 mPa·s to 50,000 mPa·s, preferably 1 mPa·s to 20,000 mPa·s, more preferably 1 mPa·s to 5,000 mPa·s, and even more preferably 1 mPa·s to 3,000 mPa·s.

[0137] If the viscosity of the second polymerizable monomer at 65°C is within the above range, the viscosity of the polymerizable composition will be low, and the dental composition can be easily prepared.

[0138] The viscosity of the second polymerizable monomer at 65°C is preferably lower than the viscosity of the first polymerizable monomer at 65°C. Note that storage at high temperatures may partially oligomerize the second polymerizable monomer, generating by-components other than the desired second polymerizable monomer, forming a mixture of the second polymerizable monomer and the by-components. However, if the viscosity of the second polymerizable monomer at 65°C is within the above range, even when using these mixtures, the influence of the by-components can be sufficiently minimized when used as a polymerizable composition or a dental material composition.

[0139] The refractive index of the second polymerizable monomer at 25°C is, for example, 1.40 to 1.70, preferably 1.45 to 1.60.

[0140] If the refractive index of the second polymerizable monomer at 25°C is within the above range, the aesthetics of dental molded articles can be improved.

[0141] The second polymerizable monomer may be used alone or in combination of two or more types.

[0142] Examples of secondary polymerizable monomers having one polymerizable group include compounds represented by the following general formula (13).

[0143]

[0144] In the above general formula (13), R ７ R is a hydrogen or methyl group, ８ This represents a monovalent organic group having 1 to 20 carbon atoms, which may contain oxygen or nitrogen.

[0145] Examples of monovalent organic groups include monovalent hydrocarbon groups and monovalent oxygen-containing hydrocarbon groups. Examples of monovalent hydrocarbon groups include monovalent acyclic hydrocarbon groups and monovalent cyclic hydrocarbon groups. Examples of monovalent acyclic hydrocarbon groups include alkyl groups, alkenyl groups, and alkynyl groups. Examples of monovalent cyclic hydrocarbon groups include cycloalkyl groups, cycloalkenyl groups, cycloalkynyl groups, and aryl groups. A monovalent oxygen-containing hydrocarbon group is a group in which oxygen is inserted between at least some of the carbon-carbon bonds of the above monovalent hydrocarbon group (however, oxygen is not inserted continuously; that is, it does not have an oxygen-oxygen bond). Examples of monovalent oxygen-containing hydrocarbon groups include alkoxyalkyl groups, alkoxyalkylene glycol groups, and tetrahydrofurfuryl groups. Note that monovalent cyclic hydrocarbon groups may have an acyclic hydrocarbon portion. Furthermore, the acyclic hydrocarbon portion included in the above functional groups may be linear or branched.

[0146] The monovalent hydrocarbon groups and monovalent oxygen-containing hydrocarbon groups mentioned above have 1 to 20 carbon atoms.

[0147] If the monovalent hydrocarbon group or monovalent oxygen-containing hydrocarbon group described above contains a linear alkylene moiety, at least one methylene group may be replaced by an ester bond, amide bond, carbonate bond, urethane bond (carbamoyl group), or urea bond (however, methylene groups may not be replaced consecutively). Preferably, it is not replaced by a urethane bond (carbamoyl group).

[0148] The hydrogen atoms contained in the above-mentioned monovalent hydrocarbon group or monovalent oxygen-containing hydrocarbon group may be replaced by functional groups such as acidic groups (e.g., carboxyl groups and phosphate groups), hydroxyl groups, amino groups, and epoxy groups.

[0149] Examples of compounds having a methacryloyl group represented by general formula (13) include methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, ethoxydiethylene glycol methacrylate, methoxytriethylene glycol methacrylate, phenoxyethyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2-hydroxybutyl methacrylate, 2-hydroxy-3-phenoxypropyl methacrylate, 4-hydroxybutyl methacrylate, and 1,4-cyclohexanedimethanol monomethacrylate.

[0150] Examples of compounds having an acryloyl group represented by general formula (13) include methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, hexyl acrylate, cyclohexyl acrylate, ethoxydiethylene glycol acrylate, methoxytriethylene glycol acrylate, phenoxyethyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxybutyl acrylate, 2-hydroxy-3-phenoxypropyl acrylate, 4-hydroxybutyl acrylate, and 1,4-cyclohexanedimethanol monoacrylate.

[0151] Examples of compounds represented by general formula (13) in which hydrogen atoms in an organic group such as a hydrocarbon group having 1 to 20 carbon atoms or an oxygen-containing hydrocarbon group having 1 to 20 carbon atoms are replaced by hydroxyl groups include 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, and dihydroxypropyl mono (meth)acrylate.

[0152] Examples of secondary polymerizable monomers having two polymerizable groups include compounds represented by the following general formula (14).

[0153]

[0154] In the above general formula (14), R ９ and R １０ Each of these represents a hydrogen or methyl group, and these may be the same or different. Preferably, R ９ and R １０ Each of these represents a methyl group. １１ represents a divalent organic group having 1 to 40 carbon atoms, which may contain oxygen or nitrogen. However, the compounds represented by the above general formula (14) do not include the first polymerizable monomer (first (meth)acrylate).

[0155] Examples of divalent organic groups include divalent hydrocarbon groups and divalent oxygen-containing hydrocarbon groups. Examples of divalent hydrocarbon groups include divalent acyclic hydrocarbon groups and divalent cyclic hydrocarbon groups. Examples of divalent acyclic hydrocarbon groups include alkylene groups, alkenylene groups, and alkylylene groups. Examples of divalent cyclic hydrocarbon groups include cycloalkylene groups, cycloalkenylene groups, cycloalkylynylene groups, and arylene groups. Divalent oxygen-containing hydrocarbon groups are groups in which oxygen is inserted between at least some of the carbon-carbon bonds of the above-mentioned divalent hydrocarbon groups (however, oxygen is not inserted continuously; that is, there is no oxygen-oxygen bond). Examples of divalent oxygen-containing hydrocarbon groups include alkoxyalkyl groups, alkoxyalkylene glycol groups, and tetrahydrofurfuryl groups. Note that divalent cyclic hydrocarbon groups may have an acyclic hydrocarbon portion. Furthermore, the acyclic hydrocarbon portion included in the above functional group may be either linear or branched.

[0156] The divalent hydrocarbon groups and monovalent oxygen-containing hydrocarbon groups mentioned above have 1 to 40 carbon atoms.

[0157] If the above-mentioned divalent hydrocarbon group or divalent oxygen-containing hydrocarbon group contains a linear alkylene moiety, at least one methylene group may be replaced by an ester bond, amide bond, carbonate bond, urethane bond (carbamoyl group), or urea bond (however, methylene groups may not be replaced consecutively). Preferably, it is not replaced by a urethane bond (carbamoyl group).

[0158] Furthermore, the hydrogen atoms contained in the above-mentioned divalent hydrocarbon groups or divalent oxygen-containing hydrocarbon groups may be replaced with functional groups such as acidic groups (e.g., carboxyl groups, phosphate groups), hydroxyl groups, amino groups, epoxy groups, or polymerizable groups such as acryloyl groups and methacryloyl groups.

[0159] R １１ Preferably, this is an alkylene group having 2 to 20 carbon atoms, more preferably an alkylene group having 2 to 12 carbon atoms.

[0160] R １１ The alkylene group has 2 to 12 carbon atoms, and examples of second polymerizable monomers having a methacryloyl group include ethylene glycol dimethacrylate, 1,3-butanediol dimethacrylate, 1,4-butanediol dimethacrylate, neopentyl glycol dimethacrylate, 1,6-hexanediol dimethacrylate, 3-methyl-1,5-pentanediol dimethacrylate, 1,8-octanediol dimethacrylate, 1,9-nonanediol dimethacrylate, 1,10-decanediol dimethacrylate, and 1,12-dodecanediol dimethacrylate. １１ A secondary polymerizable monomer is an alkylene group having 2 to 12 carbon atoms, in which one hydrogen atom of the alkylene group is replaced by a hydroxyl group, and further having a methacryloyl group, for example, glycerol dimethacrylate.

[0161] R １１The alkylene group has 2 to 12 carbon atoms, and examples of secondary polymerizable monomers having an acryloyl group include ethylene glycol diacrylate, 1,4-butanediol diacrylate, neopentyl glycol diacrylate, 1,6-hexanediol diacrylate, 3-methyl-1,5-pentanediol diacrylate, 1,8-octanediool diacrylate, 1,9-nonanediol diacrylate, and 1,10-decanediol diacrylate.

[0162] Also, R １１ This may preferably be a divalent cyclic hydrocarbon group having 1 to 40 carbon atoms. １１ Examples of secondary polymerizable monomers in which is a divalent cyclic hydrocarbon group having 1 to 40 carbon atoms include tricyclodecanedimethanol dimethacrylate, 4,4'-biphenol dimethacrylate, and 4,4'-isopropylidenediphenol dimethacrylate. １１ Examples of second polymerizable monomers in which the molecule is a divalent cyclic hydrocarbon group having 1 to 40 carbon atoms, and one hydrogen atom of the alkylene group is replaced by a hydroxyl group, include 2,2-bis(4-methacryloyloxypolyethoxyphenyl)propane and bisphenol A glycidyl methacrylate.

[0163] Furthermore, R １１ Preferably, this may be an oxyalkylene group having 2 to 20 carbon atoms, and more preferably, an oxyalkylene group having 4 to 12 carbon atoms.

[0164] R １１ Examples of second polymerizable monomers having a methacryloyl group and being an oxyalkylene group having 4 to 12 carbon atoms include diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, dipropylene glycol dimethacrylate, tripropylene glycol dimethacrylate, tetrapropylene glycol dimethacrylate, and polypropylene glycol dimethacrylate.

[0165] R １１Examples of secondary polymerizable monomers having an oxyalkylene group with 4 to 12 carbon atoms and an acryloyl group include diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, tetrapropylene glycol diacrylate, and polypropylene glycol diacrylate.

[0166] Examples of secondary polymerizable monomers having three or more polymerizable groups include trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, trimethylolpropane ethoxytriacrylate, glycerin propoxytriacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, pentaerythritol alkoxytetraacrylate, pentaerythritol ethoxytetraacrylate, ditrimethylolpropane tetraacrylate, and dipentaerythritol hexaacrylate.

[0167] Furthermore, the second polymerizable monomer may have both a polymerizable group and an acidic group, from the viewpoint of improving adhesion. Preferably, it does not have an acidic group. Examples of acidic groups include phosphate residues, pyrophosphate residues, thiophosphate residues, carboxylic acid residues, and sulfonic acid residues.

[0168] Examples of second polymerizable monomers having a methacryloyl group and a phosphate residue include 2-methacryloyloxyethyl dihydrogen phosphate, 9-methacryloyloxynonyl dihydrogen phosphate, 10-methacryloyloxydecyl dihydrogen phosphate, 11-methacryloyloxyundecyl dihydrogen phosphate, 20-methacryloyloxyeicosyl dihydrogen phosphate, 1,3-dimethacryloyloxypropyl-2-dihydrogen phosphate, 2-methacryloyloxyethylphenyl phosphate, 2-methacryloyloxyethyl 2'-bromoethyl phosphate, methacryloyloxyethylphenyl phosphonate, and their acid chlorides.

[0169] Examples of second polymerizable monomers having an acryloyl group and a phosphate residue include 2-acryloyloxyethyl dihydrogen phosphate, 9-acryloyloxynonyl dihydrogen phosphate, 10-acryloyloxydecyl dihydrogen phosphate, 11-acryloyloxyundecyl dihydrogen phosphate, 20-acryloyloxyeicosyl dihydrogen phosphate, 1,3-diacryloyloxypropyl-2-dihydrogen phosphate, 2-acryloyloxyethylphenyl phosphate, 2-acryloyloxyethyl 2'-bromoethyl phosphate, acryloyloxyethylphenyl phosphonate, and their acid chlorides.

[0170] Examples of second polymerizable monomers having a methacryloyl group and a pyrophosphate residue include di(2-methacryloyloxyethyl) pyrophosphate and their acid chlorides.

[0171] Examples of second polymerizable monomers having an acryloyl group and a pyrophosphate residue include di(2-acryloyloxyethyl) pyrophosphate and its acid chloride.

[0172] Examples of second polymerizable monomers having a methacryloyl group and a thiophosphate residue include 2-methacryloyloxyethyl dihydrogen dithiophosphate, 10-methacryloyloxydecyl dihydrogen thiophosphate, and their acid chlorides.

[0173] Examples of second polymerizable monomers having an acryloyl group and a thiophosphate residue include 2-acryloyloxyethyl dihydrogen dithiophosphate, 10-acryloyloxydecyl dihydrogen thiophosphate, and their acid chlorides.

[0174] Examples of second polymerizable monomers having a methacryloyl group and a carboxylic acid residue include 4-methacryloyloxyethoxycarbonylphthalic acid, 5-methacryloylaminopentylcarboxylic acid, and 11-methacryloyloxy-1,1-undecanedicarboxylic acid, their acid chlorides, and their acid anhydrides.

[0175] Examples of second polymerizable monomers having an acryloyl group and a carboxylic acid residue include 4-acryloyloxyethoxycarbonylphthalic acid, 5-acryloylaminopentylcarboxylic acid, and 11-acryloyloxy-1,1-undecanedicarboxylic acid, their acid chlorides, and their acid anhydrides.

[0176] Examples of second polymerizable monomers having a methacryloyl group and a sulfonic acid residue include 2-sulfoethyl methacrylate and 2-methacrylamido-2-methylpropanesulfonic acid.

[0177] Examples of second polymerizable monomers having an acryloyl group and a sulfonic acid residue include 2-sulfoethyl acrylate and 2-acrylamido-2-methylpropanesulfonic acid.

[0178] The content of the second polymerizable monomer in the polymerizable composition is, for example, 0% to 50% by mass, preferably 10% to 40% by mass, and more preferably 20% to 35% by mass. Alternatively, the content of the second polymerizable monomer in the polymerizable composition is, for example, more than 0% by mass, preferably 10% or more by mass, more preferably 20% or more by mass, and also, for example, 50% or less by mass, preferably 40% or less by mass, and more preferably 35% or less by mass.

[0179] If the content of the second polymerizable monomer in the polymerizable composition is below the above upper limit, the content of the first polymerizable monomer can be ensured. Furthermore, if the content of the second polymerizable monomer in the polymerizable composition is above the above lower limit, it prevents the content of the first polymerizable monomer from becoming excessively high. As a result, the viscosity of the polymerizable composition can be adjusted. In addition, when forming dental molded articles by pressure thermal polymerization, the occurrence of cracks can be suppressed, and the elastic modulus of the dental molded article can be adjusted.

[0180] The content of the second polymerizable monomer in the dental composition is, for example, 0.1% to 30% by mass, preferably 1% to 20% by mass, and more preferably 3% to 15% by mass. Alternatively, the content of the second polymerizable monomer in the dental composition may be, for example, 0.1% or more by mass, preferably 1% or more by mass, more preferably 3% or more by mass, or, for example, 30% or less by mass, preferably 20% or less by mass, and more preferably 15% or less by mass.

[0181] If the content of the second polymerizable monomer in the dental composition is within the above range, the content of the first polymerizable monomer and the content of the filler can be adjusted to an appropriate range. As a result, when forming dental molded articles by pressure thermal polymerization, the occurrence of cracks can be suppressed, and the elastic modulus of the dental molded article can be adjusted.

[0182] When the polymerizable composition contains the above-mentioned second polymerizable monomer having an acidic group, the amount of the second polymerizable monomer having an acidic group is appropriately adjusted within the above range, but preferably the polymerizable groups contained in the second polymerizable monomer having an acidic group are 50% or less of the total number of polymerizable groups in the polymerizable composition.

[0183] 1.2. Polymerization Initiator The polymerization initiator used in the dental composition of this disclosure is a thermal polymerization initiator. In other words, the dental composition contains a thermal polymerization initiator and is therefore thermally polymerizable.

[0184] Examples of polymerization initiators include organic peroxides having at least one peroxide bond in their molecule. If the polymerization initiator is an organic peroxide, the polymerization reaction in dental compositions can be accelerated.

[0185] The number of peroxide bonds per molecule in an organic peroxide is not particularly limited and may be one or two or more. For example, the number of peroxide bonds per molecule in an organic peroxide is 1 to 5, preferably 1 to 4, more preferably 1 to 3, and even more preferably 1 or 2.

[0186] The polymerization initiator of this disclosure has an active oxygen content of 7.00% or more and 13.00% or less. The active oxygen content is the amount of oxygen contained in the organic peroxide that can be used to form free radicals, and is expressed as the mass percentage of one oxygen atom derived from a peroxide bond. Specifically, it can be calculated using the following formula. Note that the active oxygen content of the polymerization initiator in this disclosure is the ideal active oxygen content calculated using the following formula, and is the active oxygen content when the purity of the organic peroxide is 100%. Active oxygen content (%) = (Number of peroxide bonds × 16) / (Molecular weight of organic peroxide) × 100

[0187] The amount of reactive oxygen species in the polymerization initiator is, for example, 7.00% to 13.00%, preferably 7.50% to 12.50%, more preferably 8.00% to 12.00%, even more preferably 8.25% to 11.75%, particularly preferably 8.50% to 11.50%, and most preferably 8.75% to 11.25%.

[0188] The amount of reactive oxygen species in the polymerization initiator is 7.00% or more, preferably 7.50% or more, more preferably 8.00% or more, even more preferably 8.25% or more, particularly preferably 8.50% or more, and most preferably 8.75% or more. Alternatively, the amount of reactive oxygen species in the polymerization initiator is 13.00% or less, preferably 12.50% or less, more preferably 12.00% or less, even more preferably 11.75% or less, particularly preferably 11.50% or less, and most preferably 11.25% or less.

[0189] If the amount of reactive oxygen species in the polymerization initiator is within the above range, the polymerization reaction in the dental composition can be promoted. Therefore, when forming a dental molded article by pressurized thermal polymerization, the occurrence of cracks caused by the difference in polymerization rate between the surface and the deeper parts can be suppressed. In addition, if the amount of reactive oxygen species in the polymerization initiator is within the above range, the dental composition can be prepared uniformly.

[0190] The molecular weight of the polymerization initiator is appropriately selected within the range that satisfies the amount of reactive oxygen species of the polymerization initiator described above.

[0191] When the polymerization initiator has one peroxide bond, the molecular weight of the polymerization initiator is, for example, 123 or more, preferably 128 or more, more preferably 133 or more, even more preferably 136 or more, particularly preferably 139 or more, most preferably 142 or more, and also, for example, 229 or less, preferably 214 or less, more preferably 200 or less, even more preferably 194 or less, particularly preferably 189 or less, most preferably 183 or less.

[0192] When the polymerization initiator has two peroxide bonds, the molecular weight of the polymerization initiator is 246 or more, preferably 256 or more, more preferably 266 or more, even more preferably 272 or more, particularly preferably 278 or more, most preferably 284 or more, and also, for example, 458 or less, preferably 427 or less, more preferably 400 or less, even more preferably 388 or less, particularly preferably 377 or less, most preferably 366 or less.

[0193] Examples of organic peroxides include alkyl peroxyester compounds, peroxycarbonate compounds, dialkyl peroxide compounds, peroxyketal compounds, and hydroperoxide compounds.

[0194] Alkyl peroxyester compounds are represented by the following general formula (15).

[0195]

[0196] In the above general formula (15), R １２ and R １３Each of these is, for example, a hydrocarbon group having 1 to 10 carbon atoms. １２ The carbon group is preferably a hydrocarbon group having 2 to 6 carbon atoms. More preferably, a t-butyl group and a t-amyl group are mentioned. Even more preferably, a t-amyl group is mentioned. １３ Preferably, R is a hydrocarbon group having 1 to 8 carbon atoms. More preferably, it is a hydrocarbon group having 1 to 4 carbon atoms. １２ and R １３ They may be the same, or they may be different from one another.

[0197] Examples of alkyl peroxyester compounds include t-butyl peroxyneoheptanoate, t-butyl peroxyisopropyl monocarbonate, t-butyl peroxypivalate, t-butyl peroxy-2-ethylhexanoate, t-butyl peroxyisobutyrate, t-butyl peroxybenzoate, t-butyl peroxyacetate, t-amyl peroxypivalate, t-amyl peroxybenzoate, and t-amyl peroxyacetate.

[0198] Peroxycarbonate compounds are represented by the following general formula (16).

[0199] In the above general formula (16), R １４ and R １５ Each of these is, for example, a hydrocarbon group having 1 to 10 carbon atoms. １４ The carbon group is preferably a hydrocarbon group having 2 to 6 carbon atoms. More preferably, a t-butyl group and a t-amyl group are mentioned. Even more preferably, a t-amyl group is mentioned. １５ Preferably, R is a hydrocarbon group having 1 to 6 carbon atoms. More preferably, it is a hydrocarbon group having 2 to 4 carbon atoms. １４ and R １５ They may be the same, or they may be different from one another.

[0200] Examples of peroxycarbonate compounds include t-butylperoxyisopropyl carbonate, t-amylperoxyisopropyl carbonate, and 1,6-bis-(t-butylperoxycarbonyloxy)hexane.

[0201] Dialkylperoxide compounds are represented by the following general formula (17) or general formula (18). General formula (17) represents a dialkylperoxide compound having one peroxide bond, and general formula (18) represents a dialkylperoxide compound having two peroxide bonds (excluding peroxyketal compounds, which will be discussed later).

[0202]

[0203]

[0204] In the above general formula (17), R １６ and R １７ Each of these is, for example, a hydrocarbon group having 1 to 10 carbon atoms. Preferably, it is a hydrocarbon group having 2 to 6 carbon atoms. More preferably, a t-butyl group and a t-amyl group are mentioned. Even more preferably, a t-amyl group is mentioned. Note that R １６ and R １７ They may be the same, or they may be different from one another.

[0205] In the above general formula (18), R １８ and R １９ Each of these is, for example, a hydrocarbon group having 1 to 10 carbon atoms. Preferably, it is a hydrocarbon group having 2 to 6 carbon atoms. More preferably, a t-butyl group and a t-amyl group are mentioned. Even more preferably, a t-amyl group is mentioned. Also, R ２０ For example, R is a hydrocarbon group having 1 to 12 carbon atoms. １８ , R １９ and R ２０ They may be the same, or they may be different from one another.

[0206] Examples of dialkylperoxide compounds include 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, 1,3-di(2-t-butylperoxyisopropyl)benzene, di-t-butylperoxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexine-3, and di-t-amylperoxide. Di-t-amylperoxide is preferred.

[0207] Peroxyketal compounds are represented by the following general formula (19).

[0208] In the above general formula (19), R ２１ and R ２２ Each of these is, for example, a hydrocarbon group having 1 to 10 carbon atoms. Preferably, it is a hydrocarbon group having 2 to 6 carbon atoms. More preferably, a t-butyl group and a t-amyl group are mentioned. Even more preferably, a t-amyl group is mentioned. R ２３ and R ２４ Each of these is, for example, a hydrocarbon group having 1 to 6 carbon atoms and a carboxylic acid ester group having 1 to 10 carbon atoms.

[0209] Examples of peroxyketal compounds include n-butyl 4,4-di(t-butylperoxy)valerate, ethyl 3,3-di(t-butylperoxy)butyrate, 1,1-di(t-butylperoxy)cyclohexane, 1,1-di(t-amylperoxy)cyclohexane, 1,1-di(t-hexylperoxy)cyclohexane, 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane, and 2,2-bis(4,4-di-t-butylperoxycyclohexyl)propane. Preferably, 1,1-di(t-amylperoxy)cyclohexane is used.

[0210] Hydroperoxide compounds are represented by the following general formula (20).

[0211] In the above general formula (20), R ２５For example, it is a hydrocarbon group having 1 to 10 carbon atoms. Preferably, it is a hydrocarbon group having 4 to 10 carbon atoms. More preferably, it is a hydrocarbon group having 6 to 10 carbon atoms.

[0212] Examples of hydroperoxide compounds include 1,1,3,3-tetramethylbutyl hydroperoxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, and p-menthane hydroperoxide.

[0213] Furthermore, the polymerization initiator preferably includes a compound having a t-amyl group in the above-mentioned organic peroxide, from the viewpoint of the stability of the radicals generated. In other words, the polymerization initiator preferably includes an amyl peroxide compound, from the viewpoint of the stability of the radicals generated. Examples of amyl peroxide compounds include t-amyl peroxypivalate, t-amyl peroxybenzoate, t-amyl peroxyacetate, t-amyl peroxyisopropyl carbonate, di-t-amyl peroxide, and 1,1-di(t-amyl peroxy)cyclohexane. Di-t-amyl peroxide and 1,1-di(t-amyl peroxy)cyclohexane are preferred.

[0214] If the polymerization initiator contains an amyl peroxide compound, the polymerization reaction in dental compositions can be appropriately promoted. Therefore, when forming dental molded articles by pressurized thermal polymerization, the occurrence of cracks caused by the difference in polymerization rates between the surface and the deeper parts can be suppressed.

[0215] Furthermore, among organic peroxides, peroxydicarbonate compounds (e.g., diisopropyl peroxydicarbonate, di-sec-butyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, dibenzyl peroxydicarbonate) and diacyl peroxide compounds (e.g., diisononanoyl peroxide, dilauroyl peroxide, and dibenzoyl peroxide) do not qualify as polymerization initiators in this disclosure because their reactive oxygen species content is less than 7.00%.

[0216] The half-life temperature of the polymerization initiator at 10 hours is, for example, 70°C to 150°C, preferably 80°C to 140°C, more preferably 85°C to 130°C, and even more preferably 90°C to 125°C.

[0217] The half-life temperature of the polymerization initiator at 10 hours is, for example, 70°C or higher, preferably 80°C or higher, more preferably 85°C or higher, even more preferably 90°C or higher, and also, for example, 150°C or lower, preferably 140°C or lower, more preferably 130°C or lower, and even more preferably 125°C or lower.

[0218] If the half-life temperature of the polymerization initiator (10 hours) is within the above range, crack formation can be further suppressed when forming dental molded articles by pressurized thermal polymerization.

[0219] The 10-hour half-life temperature of a polymerization initiator refers to the temperature at which the half-life of the polymerization initiator is 10 hours. Half-life is the time it takes for the concentration of the polymerization initiator to decrease to half of its initial value.

[0220] The content of polymerization initiator (solids) in the polymerizable composition is, for example, 0.1% to 10% by mass, preferably 0.2% to 5.0% by mass, and more preferably 0.3% to 3.0% by mass. Alternatively, the content of polymerization initiator (solids) in the polymerizable composition may be, for example, 0.1% or more by mass, preferably 0.2% or more by mass, more preferably 0.3% or more by mass, or, for example, 10% or less by mass, preferably 5.0% or less by mass, and more preferably 3.0% or less by mass.

[0221] If the content of polymerization initiator (solids) in the polymerizable composition is above the lower limit, the polymerization reaction in the dental composition can be promoted. Therefore, when forming dental molded articles by pressure thermal polymerization, the occurrence of cracks caused by the difference in polymerization rate between the surface and the deeper parts can be suppressed. Furthermore, if the content of polymerization initiator (solids) in the polymerizable composition is below the upper limit, the content of polymerizable monomers can be ensured. In addition, when forming dental molded articles by pressure thermal polymerization, the occurrence of excessive polymerization reactions in the surface can be suppressed.

[0222] The amount of polymerization initiator (solids) blended per 100 parts by mass of the total amount of polymerizable monomer is, for example, 0.1 to 10 parts by mass, preferably 0.2 to 5.0 parts by mass, and more preferably 0.3 to 3.0 parts by mass. The content ratio of polymerization initiator (solids) in the polymerizable composition is, for example, 0.1 parts by mass or more, preferably 0.2 parts by mass or more, more preferably 0.3 parts by mass or more, and also, for example, 10 parts by mass or less, preferably 5.0 parts by mass or less, and more preferably 3.0 parts by mass or less.

[0223] If the amount of polymerization initiator (solid content) per 100 parts by mass of polymerizable monomer is equal to or greater than the lower limit, the polymerization reaction in the dental composition can be promoted. Therefore, when forming a dental molded article by pressurized thermal polymerization, the occurrence of cracks caused by the difference in polymerization rate between the surface and the deep parts can be suppressed. If the amount of polymerization initiator (solid content) per 100 parts by mass of polymerizable monomer is equal to or less than the upper limit, when forming a dental molded article by pressurized thermal polymerization, the occurrence of excessive polymerization reaction in the surface part can be suppressed.

[0224] The content of polymerization initiator (solids) in the dental composition is, for example, 0.01% to 5.0% by mass, preferably 0.05% to 3.0% by mass, and more preferably 0.10% to 1.0% by mass. Alternatively, the content of polymerization initiator (solids) in the dental composition may be, for example, 0.01% or more by mass, preferably 0.05% or more by mass, more preferably 0.10% or more by mass, or, for example, 5.0% or less by mass, preferably 3.0% or less by mass, and more preferably 1.0% or less by mass.

[0225] If the content of polymerization initiator (solids) in the dental composition is above the lower limit, the polymerization reaction in the dental composition can be promoted. Therefore, when forming a dental molded body by pressurized thermal polymerization, the occurrence of cracks caused by the difference in polymerization rate between the surface and the deep parts can be suppressed. Furthermore, if the content of polymerization initiator (solids) in the dental composition is below the upper limit, the content ratio of polymerizable monomers to fillers can be ensured. If the content of polymerization initiator (solids) in the dental composition is below the upper limit, when forming a dental molded body by pressurized thermal polymerization, the occurrence of excessive polymerization reactions in the surface can be suppressed.

[0226] 1.3. Polymerizable Composition The polymerizable composition comprises a polymerizable monomer and a polymerization initiator. Preferably, it comprises a first polymerizable monomer, a second polymerizable monomer, and a polymerization initiator. More preferably, it comprises a first polymerizable monomer (first (meth)acrylate) having urethane bonds and thiourethane bonds, a second polymerizable monomer not having urethane bonds, and an organic peroxide as a polymerization initiator.

[0227] The polymerizable composition contains the above-mentioned polymerization initiator and therefore has thermal polymerizability.

[0228] The polymerizable composition may contain polymerizable compounds having acidic groups other than the first polymerizable monomer and the second polymerizable monomer. Examples of such polymerizable compounds having acidic groups include polymerizable compounds containing sulfonic acid residues, such as styrene sulfonic acid.

[0229] The polymerizable composition may contain polymerization initiators other than those described above. Examples of other polymerization initiators include other thermal polymerization initiators and photopolymerization initiators. Other thermal polymerization initiators include, for example, peroxydicarbonate compounds (e.g., diisopropyl peroxydicarbonate, di-sec-butyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, dibenzyl peroxydicarbonate), diacyl peroxide compounds (e.g., diisononanoyl peroxide, dilauroyl peroxide, and dibenzoyl peroxide), and azo compounds (e.g., 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobisisobutyronitrile, 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2-methylpropionate), and 2,2'-azobis(2-methylbutyronitrile)). Photopolymerization initiators include, for example, α-diketones, ketals, and thioxanthones. Examples of α-diketones include camphorquinone (CQ). Examples of ketals include benzyldimethyl ketal and benzyldiethyl ketal. Examples of thioxanthones include 2-chlorothioxanthone and 2,4-diethylthioxanthone. The polymerizable compositions of this disclosure preferably do not contain other polymerization initiators.

[0230] Furthermore, the polymerizable composition may contain the polymerization inhibitor described in the above-mentioned method for producing the first (meth)acrylate, from the viewpoint of improving storage stability. The polymerization inhibitor may be added when synthesizing the first (meth)acrylate (first polymerizable monomer), when preparing the polymerizable composition, or when preparing the dental composition.

[0231] Furthermore, the polymerizable composition may contain, as needed, bactericides, disinfectants, stabilizers, preservatives, and the like.

[0232] The polymerizable composition of this disclosure preferably comprises a first polymerizable monomer, a second polymerizable monomer, and a polymerization initiator.

[0233] A polymerizable composition is prepared by mixing a first polymerizable monomer, a second polymerizable monomer, and a polymerization initiator. The method of mixing the first polymerizable monomer, the second polymerizable monomer, and the polymerization initiator is not particularly limited. For example, one method of mixing the first polymerizable monomer, the second polymerizable monomer, and the polymerization initiator is to place them in a container and stir them while appropriately heating until they become homogeneous.

[0234] The viscosity of the polymerizable composition at 65°C is not particularly limited, but is, for example, 1 mPa·s to 100,000 mPa·s, preferably 5 mPa·s to 60,000 mPa·s, more preferably 10 mPa·s to 30,000 mPa·s, and even more preferably 100 mPa·s to 10,000 mPa·s. Note that the polymerizable composition may partially oligomerize when stored at high temperatures, but the above viscosity is the viscosity of the polymerizable composition immediately after preparation before oligomerization.

[0235] If the viscosity of the polymerizable composition at 65°C is below the above upper limit, the dispersibility of the polymerizable composition can be improved and it can be mixed uniformly in the preparation of the dental composition. Furthermore, if the viscosity of the polymerizable composition at 65°C is above the above lower limit, the incorporation of air bubbles can be suppressed and it can be mixed uniformly in the preparation of the dental composition.

[0236] Furthermore, since the polymerizable composition consists of a first polymerizable monomer and a second polymerizable monomer that are liquid at room temperature, the polymerizable composition is liquid at least immediately after preparation.

[0237] The hue of the polymerizable composition is not particularly limited, but is preferably suitable for use in dental compositions. Specifically, it is an APHA of, for example, 500 or less, preferably 200 or less, and more preferably 100 or less.

[0238] The content of polymerizable composition in dental compositions is, for example, 1.0% by mass or more, preferably 5.0% by mass or more, more preferably 10% by mass or more, even more preferably 15% by mass or more, and also, for example, 70% by mass or less, preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less.

[0239] 1.4. Fillers The fillers are not particularly limited as long as they are conventionally known fillers that can be commonly used in the dental field. Examples of fillers include organic fillers and inorganic fillers. Inorganic fillers are preferred.

[0240] Examples of organic fillers include fine powders such as polymethyl methacrylate, polyethyl methacrylate, methyl methacrylate-ethyl methacrylate copolymer, crosslinked polymethyl methacrylate, crosslinked polyethyl methacrylate, ethylene-vinyl acetate copolymer, and styrene-butadiene copolymer.

[0241] Examples of inorganic fillers include glass (mainly composed of silicon dioxide, and containing oxides of heavy metals such as boron and aluminum as needed), ceramics, diatomaceous earth, kaolin, clay minerals (e.g., montmorillonite), activated clay, synthetic zeolite, silica, silica-alumina, alumina, alumina-quartz, titania, zirconia, mica, calcium phosphate, barium sulfate, hydroxyapatite, calcium fluoride, and ytterbium fluoride. Examples of silica include fumed silica. Examples of glass include barium glass (e.g., barium-silica glass) and ceramic glass.

[0242] More specifically, examples of inorganic fillers include barium borosilicate glass (e.g., Kimble Raysorb T3000, Schott 8235, Schott GM27884, and Schott GM39923), strontium boroaluminosilicate glass (e.g., Raysorb T4000, Schott G018-093, and Schott GM32087), lanthanum glass (e.g., Schott GM31684), fluoroaluminosilicate glass (e.g., Schott G018-091, and Schott G018-117), and zirconium and / or cesium-containing boroaluminosilicate glass (e.g., Schott G018-307, G018-308, and G018-310).

[0243] The inorganic filler may be hydrophobic or hydrophilic by surface treatment with a silane coupling agent or the like. Examples of silane coupling agents include organosilicon compounds. Examples of organosilicon compounds include γ-methacryloxyalkyltrimethoxysilane (number of carbon atoms between the methacryloxy group and the silicon atom: 3 to 12), γ-methacryloxyalkyltriethoxysilane (number of carbon atoms between the methacryloxy group and the silicon atom: 3 to 12), vinyltrimethoxysilane, vinylethoxysilane, and vinyltriacetoxysilane.

[0244] The filler may be used alone or in combination of two or more types. Preferably, two or more types are used in combination.

[0245] The filler preferably comprises a first filler and a second filler having different particle sizes. More preferably, it consists of a first filler and a second filler having different particle sizes.

[0246] If the filler includes a first filler and a second filler with different particle sizes, it is possible to improve the bending strength of the dental molded body while suppressing the inclusion of air bubbles in the dental molded body.

[0247] The first filler may be an organic filler or an inorganic filler. Preferably, it is an inorganic filler (first inorganic filler). The second filler may also be an organic filler or an inorganic filler. Preferably, it is an inorganic filler (second inorganic filler). The materials of the first filler and the second filler may be the same or different from each other.

[0248] In other words, the filler preferably comprises a first inorganic filler and a second inorganic filler having different particle sizes. More preferably, it consists of a first inorganic filler and a second inorganic filler having different particle sizes.

[0249] If the filler includes a first inorganic filler and a second inorganic filler with different particle sizes, it is possible to improve the bending strength of the dental molded body while suppressing the inclusion of air bubbles in the dental molded body.

[0250] The materials of the first inorganic filler and the second inorganic filler (such as the glass mentioned above) may be the same or different. Preferably, they are the same.

[0251] The particle size of the first filler is smaller than the particle size of the second filler. If the first filler is the first inorganic filler and the second filler is the second inorganic filler, the particle size of the first inorganic filler is smaller than the particle size of the second inorganic filler. In the following, if the first filler is the first inorganic filler and the second filler is the second inorganic filler, the first filler can be read as the first inorganic filler and the second filler as the second inorganic filler.

[0252] The ratio of the particle size of the second filler to the particle size of the first filler is, for example, 1.2 to 7.0, preferably 1.5 to 6.0, more preferably 1.8 to 6.0, and even more preferably 2.0 to 5.5. Also, the ratio of the particle size of the second filler to the particle size of the first filler is, for example, 1.2 or more, preferably 1.5 or more, more preferably 1.8 or more, even more preferably 2.0 or more, and also, for example, 7.0 or less, preferably 6.0 or less, more preferably 5.5 or less, even more preferably 5.0 or less, and particularly preferably 4.0 or less.

[0253] If the ratio of the particle size of the second filler to the particle size of the first filler is within the above range, it is possible to further improve the bending strength of the dental molded body while suppressing the inclusion of air bubbles in the dental molded body.

[0254] The difference between the particle size of the first filler and the particle size of the second filler (particle size of the second filler - particle size of the first filler) is, for example, 0.1 μm or more, preferably 0.3 μm or more, more preferably 0.5 μm or more, even more preferably 0.7 μm or more, or, for example, 5.0 μm or less, preferably 4.0 μm or less, more preferably 3.0 μm or less, even more preferably 2.0 μm or less, and particularly preferably 1.5 μm or less.

[0255] The particle size of the first filler is, for example, 0.05 μm or more, preferably 0.10 μm or more, more preferably 0.20 μm or more, and also, for example, 3.0 μm or less, preferably 1.5 μm or less, more preferably 1.0 μm or less.

[0256] The particle size of the second filler is, for example, 0.1 μm or more, preferably 0.5 μm or more, more preferably 1.0 μm or more, and also, for example, 5.0 μm or less, preferably 4.0 μm or less, more preferably 3.0 μm or less, even more preferably 2.0 μm or less, and particularly preferably 1.8 μm or less.

[0257] The particle sizes of the first and second fillers are defined as the median diameter in the volume-based particle size distribution (the particle size at which the volume cumulative frequency reaches 50% from the smallest diameter side), and can be determined, for example, based on the particle size distribution obtained by laser diffraction / scattering.

[0258] The ratio of the amount of the second filler to the amount of the first filler is, for example, 0.20 to 5.0, preferably 0.25 to 4.0, more preferably 0.30 to 3.5, and even more preferably 0.33 to 3.0. Also, the ratio of the amount of the second filler to the amount of the first filler is, for example, 0.20 or more, preferably 0.25 or more, more preferably 0.30 or more, even more preferably 0.33 or more, and also, for example, 5.0 or less, preferably 4.0 or less, more preferably 3.5 or less, and even more preferably 3.0 or less.

[0259] If the ratio of the amount of the second filler to the amount of the first filler is within the above range, it is possible to suppress the inclusion of air bubbles in the dental molded body while adjusting the bending strength and elastic modulus of the dental molded body to an appropriate range.

[0260] The amount of the first filler blended with 100 parts by mass of polymerizable composition is, for example, 10 parts by mass or more, preferably 50 parts by mass or more, more preferably 80 parts by mass or more, even more preferably 100 parts by mass or more, and also, for example, 500 parts by mass or less, preferably 450 parts by mass or less, more preferably 400 parts by mass or less, even more preferably 350 parts by mass or less.

[0261] If the amount of the first filler added to 100 parts by mass of the polymerizable composition is within the above range, the inclusion of air bubbles in the dental molded product can be suppressed.

[0262] The amount of the second filler added per 100 parts by mass of the polymerizable composition is, for example, 10 parts by mass or more, preferably 50 parts by mass or more, more preferably 80 parts by mass or more, even more preferably 100 parts by mass or more, and also, for example, 500 parts by mass or less, preferably 450 parts by mass or less, more preferably 400 parts by mass or less, and even more preferably 350 parts by mass or less.

[0263] If the amount of the second filler added to 100 parts by mass of the polymerizable composition is within the above range, the bending strength of the dental molded article can be improved.

[0264] The content of the first filler in the dental composition is, for example, 5% by mass or more, preferably 10% by mass or more, more preferably 15% by mass or more, even more preferably 20% by mass or more, and also, for example, 95% by mass or less, preferably 85% by mass or less, more preferably 80% by mass or less, and even more preferably 60% by mass or less.

[0265] If the content ratio of the first filler in the dental composition is within the above range, the inclusion of air bubbles in the dental molded product can be suppressed.

[0266] The content of the second filler in the dental composition is, for example, 5% by mass or more, preferably 10% by mass or more, more preferably 15% by mass or more, even more preferably 20% by mass or more, and also, for example, 95% by mass or less, preferably 85% by mass or less, more preferably 80% by mass or less, and even more preferably 60% by mass or less.

[0267] If the content ratio of the second filler in the dental composition is within the above range, the bending strength of the dental molded article can be improved.

[0268] The particle size of the filler is, for example, 0.05 μm or more, preferably 0.10 μm or more, more preferably 0.20 μm or more, and also, for example, 5.0 μm or less, preferably 4.0 μm or less, more preferably 3.0 μm or less.

[0269] The particle size of the filler can be calculated from the particle sizes of the first and second fillers, and the content ratio of the first and second fillers.

[0270] The amount of filler added per 100 parts by mass of polymerizable composition is, for example, 50 parts by mass or more, preferably 100 parts by mass or more, more preferably 150 parts by mass or more, even more preferably 200 parts by mass or more, or, for example, 800 parts by mass or less, preferably 700 parts by mass or less, more preferably 650 parts by mass or less, even more preferably 600 parts by mass or less.

[0271] If the amount of filler added per 100 parts by mass of polymerizable composition is below the above upper limit, it is possible to suppress the excessive increase in the elastic modulus of the dental molded article. In other words, it is possible to suppress the brittleness of the dental molded article. Furthermore, if the amount of filler added per 100 parts by mass of polymerizable composition is above the above lower limit, it is possible to improve the elastic modulus of the dental molded article.

[0272] The filler content in the dental composition is, for example, 30% by mass or more, preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, and also, for example, 99% by mass or less, preferably 95% by mass or less, more preferably 90% by mass or less, and even more preferably 85% by mass or less.

[0273] If the filler content in the dental composition is below the upper limit, it is possible to suppress the excessive increase in the elastic modulus of the dental molded body. In other words, it is possible to suppress the brittleness of the dental molded body. Furthermore, the dental composition can be uniformly mixed and easily injected into a predetermined mold. Also, if the filler content in the dental composition is above the lower limit, the elastic modulus of the dental molded body can be improved.

[0274] As described above, the dental compositions of this disclosure may optionally include additives other than polymerizable compositions and fillers. For example, additives may include polymerization inhibitors described in the above-described method for producing the first (meth)acrylate to improve storage stability. They may also include pigments such as known pigments and dyes to adjust the color tone. Furthermore, reinforcing materials such as known fibers may be included to improve the flexural strength and elastic modulus of the dental molded article. Other examples of additives include thickeners, coupling agents, ultraviolet absorbers, fluorescent agents, and solvents.

[0275] The dental compositions of this disclosure are prepared by kneading a polymerizable composition, a filler, and additives as needed. The method of kneading the polymerizable composition, the filler, and additives as needed is not particularly limited. For example, one method of kneading the polymerizable composition, the filler, and additives as needed is to add the filler to the polymerizable composition prepared in a container and knead until homogeneous. Additives as needed can be added at any time.

[0276] Dental compositions are solid at room temperature. Specifically, dental compositions are paste-like at room temperature.

[0277] 2. Dental molded bodies: Dental molded bodies are hardened products of the above-mentioned dental compositions. In a CAD / CAM system, dental prostheses are manufactured by cutting the dental molded bodies using an automatically controlled milling device.

[0278] Dental molded articles can be formed by thermal polymerization of the above-mentioned dental composition. The method for thermal polymerization of the dental composition is not particularly limited, and known methods can be used. Dental molded articles are formed by a manufacturing method that includes the steps of injecting the above-mentioned paste-like dental composition into a predetermined mold, and pressurizing and heating the dental composition in the mold to polymerize and harden the dental material composition.

[0279] In pressurized thermal polymerization, the pressure is, for example, 800 kgf / cm². ２ ~2500kgf / cm ２ Preferably, 1200 kgf / cm²２ ~2000kgf / cm ２ The temperature for pressurized thermal polymerization is, for example, 80°C to 250°C, preferably 120°C to 200°C, and more preferably 140°C to 180°C. The pressurizing and heating time for pressurized thermal polymerization is appropriately adjusted depending on the pressure and temperature, for example, 1 minute to 120 minutes, preferably 3 minutes to 60 minutes, and more preferably 5 minutes to 30 minutes.

[0280] The bending strength of the dental molded article is, for example, 200 MPa or more, preferably 210 MPa or more, more preferably 220 MPa or more, even more preferably 230 MPa or more, and particularly preferably 240 MPa or more. The upper limit of the bending strength of the dental molded article is not particularly limited, but for example, it is 500 MPa or less.

[0281] If the bending strength of a dental molded body is above the lower limit mentioned above, it has sufficient toughness to be used as a dental material such as a dental prosthesis. In particular, if the bending strength of a dental molded body is 240 MPa or higher, it can be suitably used as a dental material such as a dental prosthesis for areas with high occlusal forces, such as molars.

[0282] The bending strength of a dental molded body can be measured by the method described in the examples below.

[0283] The elastic modulus of the dental molded article is, for example, 10.0 GPa or more, preferably 11.0 GPa or more, more preferably 12.0 GPa or more, even more preferably 12.5 GPa or more, particularly preferably 13.0 GPa or more, and also, for example, 18.0 GPa or less, preferably 17.0 GPa or less, more preferably 16.0 GPa or less, even more preferably 15.5 GPa or less, particularly preferably 15.0 GPa or less.

[0284] If the elastic modulus of a dental molded body is above the lower limit mentioned above, it will have sufficient rigidity as a dental material for dental prostheses and other dental devices. Furthermore, if the elastic modulus of a dental molded body is below the upper limit mentioned above, excessive brittleness can be suppressed.

[0285] The elastic modulus of a dental molded article can be measured by the method described in the examples below.

[0286] 3. Effects (1) The dental composition of this disclosure comprises a polymerizable monomer, a polymerization initiator having an active oxygen content of 7.00% or more and 13.00% or less, and a filler. Therefore, when forming a dental molded article by pressurized thermal polymerization, the occurrence of cracks caused by the difference in polymerization rate between the surface and the deep part can be suppressed. In addition, the dental composition can be prepared uniformly.

[0287] (2) In the dental compositions of this disclosure, the half-life temperature of the polymerization initiator is 70°C or higher and 150°C or lower. Therefore, when forming dental molded articles by pressure thermal polymerization, the occurrence of cracks can be further suppressed.

[0288] (3) The dental composition of this disclosure includes a first polymerizable monomer having a urethane bond and a thiourethane bond. Therefore, the flexural strength of the dental molded article can be improved.

[0289] (4) In the dental composition of the present disclosure, the first polymerizable monomer further has an aromatic ring. Therefore, the flexural strength of the dental molded article can be improved.

[0290] (5) In the dental composition of this disclosure, the polymerizable monomer includes a second polymerizable monomer that does not have a urethane bond. Therefore, the viscosity of the polymerizable composition can be adjusted. Furthermore, when forming a dental molded article by pressure thermal polymerization, the occurrence of cracks can be suppressed, and the elastic modulus of the dental molded article can be adjusted.

[0291] (6) The dental composition of the present disclosure includes a first filler and a second filler having different particle sizes. Therefore, it is possible to improve the bending strength of the dental molded article while suppressing the inclusion of air bubbles in the dental molded article.

[0292] (7) In the dental composition of this disclosure, the ratio of the particle size of the second filler to the particle size of the first filler is 1.5 or more and 6.0 or less. Therefore, the bending strength of the dental molded article can be further improved while suppressing the inclusion of air bubbles in the dental molded article.

[0293] (8) In the dental composition disclosed herein, the ratio of the amount of the second filler to the amount of the first filler is 0.3 or more and 3.5 or less. Therefore, the bending strength and elastic modulus of the dental molded body can be adjusted to an appropriate range while suppressing the inclusion of air bubbles in the dental molded body.

[0294] (9) In the dental composition of this disclosure, the filler content in the dental composition is 85.0% by mass or less. Therefore, it is possible to suppress the elastic modulus of the dental molded article from becoming excessively high. In other words, it is possible to suppress the brittleness of the dental molded article. Furthermore, the dental composition can be uniformly mixed and the dental composition can be easily injected into a predetermined mold.

[0295] (10) In the dental composition of the present disclosure, the polymerization initiator contains an amyl peroxide compound. Therefore, the polymerization reaction in the dental composition can be promoted. Therefore, when forming a dental molded article by pressurized thermal polymerization, the occurrence of cracks caused by the difference in polymerization rate between the surface and the deep part can be suppressed.

[0296] (11) The dental molded articles of this disclosure are cured products of the above dental compositions. Therefore, cracks caused by differences in polymerization rates between the surface and the deeper parts are suppressed.

[0297] 4. Modified Examples In the modified examples, the same reference numerals are used for components and processes as in the first embodiment, and their detailed descriptions are omitted. Furthermore, the modified examples can achieve the same effects and advantages as the first embodiment unless otherwise specified. Moreover, the first embodiment and its modified examples can be combined as appropriate.

[0298] In the dental composition of one embodiment described above, a first (meth)acrylate was given as the first polymerizable monomer, but the invention is not limited to this, as long as it has the polymerizable group described above (preferably an ethylenically unsaturated group) and is polymerizable.

[0299] Specifically, examples of first polymerizable monomers include monomers having urethane bonds. Preferably, (meth)acrylates having urethane bonds are included. The above-mentioned first (meth)acrylate has both urethane bonds and thiourethane bonds, but the modified (meth)acrylate having urethane bonds does not have thiourethane bonds.

[0300] Examples of (meth)acrylates having a urethane bond include [2,2,4-trimethylhexamethylenebis(2-carbamoyloxyethyl)]di(meth)acrylate. Preferably, [2,2,4-trimethylhexamethylenebis(2-carbamoyloxyethyl)]dimethacrylate (UDMA) is used.

[0301] 5. Applications The dental compositions and dental molded articles of this disclosure can be suitably used as dental materials. Specifically, the dental compositions and dental molded articles of this disclosure can be suitably used, for example, as dental restorative materials (e.g., composite resins for crowns, composite resins for filling carious cavities, composite resins for core buildup, and composite resins for filling and restorative purposes), denture base resins, denture base relining materials, impression materials, luthing materials (e.g., resin cements and resin-added glass ionomer cements), dental adhesives (e.g., orthodontic adhesives and cavity application adhesives), dental fissure sealing materials, CAD / CAM mill blanks, temporary crowns, and artificial tooth materials. The dental compositions and dental molded articles of this disclosure can be particularly suitably used as CAD / CAM mill blanks.

[0302] Examples and comparative examples are shown below to further illustrate this disclosure, but this disclosure is not limited thereto. Specific numerical values ​​such as formulation ratios (concentrations), physical properties, and parameters used in the following description may be replaced with the corresponding upper limits ("less than" and "less than") or lower limits ("greater than" and "greater than") of the formulation ratios (concentrations), physical properties, and parameters described in the "Modes for Carrying Out the Invention" above.

[0303] The components used in the examples and comparative examples are as follows: DBTDL: Dibutyltin dilaurate BHT: Dibutylhydroxytoluene XDI: m-Xylylene diisocyanate THIOL: A mixture of 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaoundecane, 4,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaoundecane, and 4,8-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaoundecane HPA: 2-Hydroxypropyl acrylate UDMA: 2,2,4-Trimethylhexamethylenebis(2-carbamoyloxyethyl) dimethacrylate (manufactured by SARTOMER) DCP: Tricyclodecane dimethanol dimethacrylate NPG: Neopentyl glycol dimethacrylate INI-1: Di-t-amyl peroxide (Trade name: Luperox DTA, Organic peroxide concentration: 93% by mass or more, Reactive oxygen species: 9.2%) INI-2: 1,1-di(t-amyl peroxy)cyclohexane (Trade name: Luperox 531, Organic peroxide concentration: 80% by mass, Reactive oxygen species: 11.1%) INI-3: 2,2-di(t-butyl peroxy)butane (Trade name: Luperox 220, Organic peroxide concentration: 50% by mass, Reactive oxygen species: 13.7%) INI-4: t-butyl peroxy 2-ethylhexyl carbonate (Trade name: Luperox TBEC, Organic peroxide concentration: 94% by mass or more, Reactive oxygen species concentration: 6.5%) INI-5: Dibenzoyl peroxide (Trade name: Luperox A75, Organic peroxide concentration: 75% by mass, Reactive oxygen species concentration: 6.6%) F 0.4 μm: Barium silica glass filler with an average primary particle size of 0.4 μm F 1.5 μm: Barium silica glass filler with an average primary particle size of 1.5 μm F 2.0 μm: Barium silica glass filler with an average primary particle size of 2.0 μm

[0304] (Synthesis of TUA) In a 100 mL four-necked flask equipped with a thoroughly dried stirring blade and thermometer, 0.1 parts by mass of DBTDL, 0.05 parts by mass of BHT, 21.08 parts by mass of XDI, and 0.62 parts by mass of THIOL were charged and dissolved to form a homogeneous solution. The mixture was then reacted at 80°C for 4 hours. After the reaction, the solution was heated to 90°C, and 28.30 parts by mass of HPA were added dropwise over 1 hour. During the dropwise addition, the temperature of the solution rose due to the heat of reaction, so the amount added was controlled to keep the temperature below 90°C. After the entire amount of HPA had been added, the solution temperature was maintained at 90°C and the mixture was reacted for 10 hours. The endpoint of the reaction was confirmed by analysis using HPLC. In this way, 50 g of thiourethane acrylate (TUA), represented by the above general formula (3), was obtained. TUA is the above-mentioned first (meth)acrylate. The viscosity of the obtained TUA at 65°C was 710 mPa·s, and the refractive index at 25°C was 1.5186. Viscosity was measured using an E-type viscometer (TVE-22H, manufactured by Toki Sangyo Co., Ltd.). The temperature for viscosity measurement was controlled to 65°C using a circulating constant-temperature water bath. The refractive index was measured using an Abbe-type fully digital refractometer (Abbemat 550, manufactured by Anton Paar Corporation) at a wavelength of 589.3 nm. The temperature for refractive index measurement was controlled to 25°C.

[0305] Example 1 A dental molded body of Example 1 was prepared according to the procedure shown below.

[0306] (Polymerizable composition: Preparation Example 1) 70 parts by mass of TUA as the first polymerizable monomer, 30 parts by mass of DCP as the second polymerizable monomer, and 1 part by mass of INI-1 as a polymerization initiator were placed in a container and stirred at 50°C until homogeneous to obtain the polymerizable composition of Preparation Example 1 shown in Table 1. The upper numbers in Table 1 represent the amount of INI-1 used as a polymerization initiator (amount of Luperox DTA), and the lower numbers in parentheses represent the amount of di-t-amyl peroxide used as an organic peroxide in the polymerization initiator. The amount of di-t-amyl peroxide used is 93% by mass or more of 1.0 part by mass of the polymerization initiator, that is, 0.93 parts by mass to 1.0 part by mass.

[0307] (Dental Molded Body) 20 parts by mass of the polymerizable composition of Preparation Example 1, 40 parts by mass of F0.4 μm (first inorganic filler) and 40 parts by mass of F1.5 μm (second inorganic filler) as fillers (inorganic fillers) were placed in a container, and mixed and kneaded at 40°C until homogenized to obtain the dental composition of Example 1. Next, the obtained dental composition was poured into a SUS mold measuring 14.5 mm × 14.5 mm × 18 mm, heated to 160°C, and molded under a pressure of 1600 kgf / cm². ２ The material was then subjected to pressurized thermal polymerization for 10 minutes to obtain the dental molded article of Example 1.

[0308] Examples 2-12 and Comparative Examples 1-3 Dental molded articles of Examples 2-12 and Comparative Examples 1-3 were prepared according to the procedure shown below.

[0309] (Polymerizable compositions: Preparation Examples 2-6, Comparative Preparation Examples 1-5) As shown in Table 1, polymerizable compositions of Preparation Examples 2-6 and Comparative Preparation Examples 1-5 were prepared in the same manner as Preparation Example 1, except that the polymerizable monomer and / or polymerization initiator were changed. The numbers in the upper part of Table 1 represent the amounts of INI-1 to INI-5 used as polymerization initiators, and the numbers in parentheses in the lower part of Table 1 represent the amounts of organic peroxides used in the polymerization initiators. Specifically, in Preparation Example 2, the amount of 1,1-di(t-amylperoxy)cyclohexane used as an organic peroxide in the polymerization initiator was 80% by mass of 1.0 part by mass of the polymerization initiator, or 0.80 parts by mass. In Preparation Example 3, the amount of 1,1-di(t-amylperoxy)cyclohexane used as an organic peroxide in the polymerization initiator was 80% by mass of 1.2 parts by mass of the polymerization initiator, or 0.96 parts by mass. In Preparation Examples 4 to 6, the amount of di-t-amyl peroxide as an organic peroxide in the polymerization initiator is 93% by mass or more of 1.0 part by mass of the polymerization initiator, i.e., 0.93 parts by mass to 1.0 part by mass. In Comparative Preparation Example 1, the amount of 2,2-di(t-butylperoxy)butane as an organic peroxide in the polymerization initiator is 50% by mass of 1.0 part by mass of the polymerization initiator, i.e., 0.50 parts by mass. In Comparative Preparation Example 2, the amount of t-butylperoxy 2-ethylhexyl carbonate as an organic peroxide in the polymerization initiator is 94% by mass or more of 1.0 part by mass of the polymerization initiator, i.e., 0.94 parts by mass to 1.0 part by mass. In Comparative Preparation Example 3, the amount of dibenzoyl peroxide as an organic peroxide in the polymerization initiator is 70% by mass of 1.0 part by mass of the polymerization initiator, i.e., 0.70 parts by mass. In comparative preparation example 4, the amount of 2,2-di(t-butylperoxy)butane as an organic peroxide in the polymerization initiator is 50% by mass of 1.9 parts by mass of the polymerization initiator, or 0.95 parts by mass. In comparative preparation example 5, the amount of dibenzoyl peroxide as an organic peroxide in the polymerization initiator is 70% by mass of 1.3 parts by mass of the polymerization initiator, or 0.975 parts by mass.

[0310] (Dental Molded Articles) As shown in Table 2, dental compositions and dental molded articles of Examples 2 to 13 and Comparative Examples 1 to 5 were obtained in the same manner as in Example 1, except that the type and amount of polymerizable composition and the type and amount of filler (inorganic filler) were changed.

[0311] [Evaluation] (Bending strength and modulus of elasticity) The bending strength of the dental molded bodies of each example and comparative example was measured. Specifically, test specimens (1.2 mm × 4 mm × 14 mm) of the dental molded bodies were prepared using a diamond cutter and polished with #2000 abrasive paper. The polished test specimens were immersed in water at 37°C for one week, and the bending strength and modulus of elasticity of the removed test specimens were measured using a universal testing machine (manufactured by Shimadzu Corporation). The test conditions were a crosshead speed of 1 mm / min and a three-point bending test method with a support distance of 12 mm. The results are shown in Table 2.

[0312] (Appearance (Cracks)) The appearance of the dental molded articles of each example and comparative example was checked for the presence or absence of cracks. Specifically, the presence or absence of cracks in the dental molded articles was checked visually and further checked using a microscope (magnification ×10 to 50). In addition, when test pieces of the dental molded articles were prepared for the evaluation of bending strength described above, the presence or absence of cracks was checked visually. The presence or absence of cracks was evaluated according to the following criteria. The results are shown in Table 2. {Criteria} A: No cracks were observed. B: Cracks were observed (cracks were observed in any of the above observations).

[0313]

[0314]

[0315] [Discussion] Examples 1 to 13 contain polymerization initiators with reactive oxygen species content ranging from 7.00% to 13.00%. Therefore, no cracks were observed in the visual evaluation. On the other hand, Comparative Examples 1 and 4 contain polymerization initiators with reactive oxygen species content greater than 13.00%, and therefore cracks were observed in the visual evaluation. Furthermore, Comparative Examples 2, 3, and 5 contain polymerization initiators with reactive oxygen species content less than 7.00%, and therefore cracks were observed in the visual evaluation.

[0316] Examples 1-6, 10, and 11 contain a first (meth)acrylate having urethane and thiourethane bonds as the first polymerizable monomer, and further contain a first filler (first inorganic filler) and a second filler (second inorganic filler) with different particle sizes. As a result, they exhibited relatively high flexural strength and toughness. In other words, they can be suitably used as dental materials such as dental prostheses for areas with high occlusal forces, such as molars.

[0317] Although the above invention is provided as an illustrative embodiment of this disclosure, it is merely illustrative and should not be interpreted restrictively. Modifications of this disclosure that are obvious to those skilled in the art are included in the claims below.

[0318] The dental compositions and dental molded articles of this disclosure are used in dental treatment.

Claims

1. A dental composition comprising a polymerizable monomer, a polymerization initiator, and a filler, wherein the amount of active oxygen in the polymerization initiator is 7.00% or more and 13.00% or less.

2. The dental composition according to claim 1, wherein the half-life temperature of the polymerization initiator at 10 hours is 70°C or higher and 150°C or lower.

3. The dental composition according to claim 1, wherein the polymerizable monomer comprises a first polymerizable monomer having a urethane bond and a thiourethane bond.

4. The dental composition according to claim 3, wherein the first polymerizable monomer further comprises an aromatic ring.

5. The dental composition according to claim 1, wherein the polymerizable monomer comprises a second polymerizable monomer that does not have a urethane bond.

6. The dental composition according to claim 1, wherein the filler comprises a first filler and a second filler having different particle sizes.

7. The dental composition according to claim 6, wherein the ratio of the particle size of the second filler to the particle size of the first filler is 1.5 or more and 6.0 or less.

8. The dental composition according to claim 6, wherein the ratio of the amount of the second filler to the amount of the first filler is 0.3 or more and 3.5 or less.

9. The dental composition according to claim 1, wherein the content of the filler in the dental composition is 85.0% by mass or less.

10. The dental composition according to claim 1, wherein the polymerization initiator comprises an amyl peroxide compound.

11. A dental molded article which is a cured product of a dental composition according to any one of claims 1 to 10.

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