A photoinitiator containing an aryliodonium salt for a dental light-curable composition

Abstract

To provide a photopolymerization initiator that exhibits excellent sensitivity to photopolymerization and can secure a sufficient pot life for ambient light, and a dental photocurable composition comprising the photopolymerization initiator.SOLUTION: A photopolymerization initiator and a dental photocurable composition are provided. (c) The photopolymerization initiator used in a dental photocurable composition comprises, (c-1) a photosensitizer, (c-2) polymerization accelerator, and (c-3) an aryliodonium salt represented by Formula (1). In the formula, R1 represents an organic group bonded to I, R2 represents an alkyl group in which one or more of hydrogen atoms is replaced with a fluorine atom, and b indicates the number thereof, which is an integer of 1 to 5.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a dental photocurable composition and a photoinitiator used in the dental photocurable composition.

Background Art

[0002] In the dental field, dental photocurable compositions are used for oral treatments and are applied to dental adhesives, dental composite resins, dental abutment building materials, dental resin cements, dental surface coatings, dental pit and fissure sealants, dental manicure materials, and the like.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, sufficient physical properties could not be obtained with the photoinitiators used in dental photocurable compositions.

[0005] Patent Documents 1 and 2 propose a photoinitiator comprising a photoacid generator (a triazine compound or a specific aryliodonium salt), a sensitizer, and an electron donor compound as the photoinitiator, but sufficient physical properties could not be obtained.

[0006] There is a demand for a photoinitiator that exhibits excellent sensitivity to photopolymerization and can ensure a sufficient pot life against ambient light, and an object of the present invention is to provide a dental photocurable composition containing the photoinitiator.

Means for Solving the Problems

[0007] The present invention relates to a (c) photoinitiator used in a dental photocurable composition, (c-1) a photosensitizer, (c-2) a polymerization accelerator, and (c-3) a formula (1):

[0008] [Chemical formula] (In the formula, R1 represents an organic group bonded to I, R2 represents an alkyl group in which a part of hydrogen atoms is substituted with fluorine atoms, b represents the number thereof, and is an integer of 1 to 5) an aryliodonium salt represented by is a photoinitiator containing [Advantages of the Invention]

[0009] The photoinitiator of the present invention exhibits excellent sensitivity to irradiation light and enables the production of a dental photocurable composition that ensures a sufficient pot life against ambient light. In addition, the dental photocurable composition containing the photoinitiator of the present invention has excellent flexural strength. [Embodiments for Carrying Out the Invention]

[0010] In the (c) photoinitiator of the present invention, the formula (1) of (c-3) may be an aryliodonium salt in which R2 is an alkyl group in which 80% or more of hydrogen atoms are substituted with fluorine atoms.

[0011] A dental photocurable composition containing the (c) photoinitiator and (a) a polymerizable monomer may also be used. A dental photocurable composition containing the (c) photoinitiator, (a) a polymerizable monomer, and (b) a filler may also be used.

[0012] A dental photocurable composition containing, per 100 parts by mass of (a) a polymerizable monomer, 0.1 to 5 parts by mass of (c-1) a photosensitizer, 0.01 to 10 parts by mass of (c-2) a polymerization accelerator, and 0.01 to 10 parts by mass of (c-3) an aryliodonium salt represented by formula (1) may also be used. It may also be a dental photocurable composition in which (a) the filler contains 10 to 1900 parts by weight with respect to 100 parts by weight of the polymerizable monomer.

[0013] It may also be a dental photocurable composition that is a dental adhesive, a dental composite resin, a dental abutment building material, a dental resin cement, a dental surface coating material, a dental pit and fissure sealant, or a dental manicure material.

[0014] Hereinafter, each component in the dental photocurable composition of the present invention will be described in detail. The present invention relates to a photopolymerization initiator and a dental photocurable composition containing the photopolymerization initiator. The dental photocurable composition of the present invention is applied as a dental adhesive, a dental composite resin, a dental abutment building material, a dental resin cement, a dental surface coating material, a dental pit and fissure sealant, or a dental manicure material.

[0015] In dental clinics, in order to aesthetically and functionally restore tooth defects caused by dental caries, fractures, etc., after pretreatment with a dental adhesive, direct restoration with a dental composite resin or an indirect restoration in which a prosthetic device made of ceramics or hard resin is attached using a dental resin cement is performed. Dental composite resins and dental resin cements are prepared by mixing a resin matrix composed of several types of polymerizable monomers, various fillers such as inorganic fillers and organic-inorganic composite fillers, and a polymerization initiator to form a uniform paste. Dental composite resin for filling is filled into a tooth in the state of an uncured paste, and after imparting the anatomical form of a natural tooth with a dental instrument such as an instrument, it is cured by irradiating light with a dental light irradiator or the like. The irradiation light from the light irradiator generally uses a light source with an output of about 100 to 2000 mW / cm 2 in the wavelength range of about 360 to 500 nm. On the other hand, dental resin cement is used when attaching a prosthetic device to a cavity or abutment tooth, and is cured by irradiating light after attaching the prosthetic device to the cavity or abutment tooth.

[0016] As photoinitiators for dental composite resins and dental resin cements, systems combining photosensitizers and appropriate photopolymerization accelerators for photosensitizers are widely used. As photosensitizers, acylphosphine oxide compounds and α-diketone compounds are known. In particular, α-diketone compounds have a polymerization initiation ability in the wavelength range of visible light that has little effect on the human body. In addition, tertiary amine compounds are well known as polymerization accelerators combined with photosensitizers. The combination of an α-diketone compound and a tertiary amine compound has high polymerization activity with respect to irradiated light, and thus is used in the field of dental materials. The dental photocurable composition containing the photoinitiator exhibits excellent mechanical properties such as hardness, flexural strength, and compressive strength required for dental filling composite resins and dental resin cements.

[0017] However, when the combination of the above-mentioned α-diketone compound and tertiary amine compound is used as a photoinitiator, there is a problem of poor environmental light stability. That is, it is carried out under white light (ambient light) such as a dental light or an indoor light such as a fluorescent lamp that illuminates the oral cavity by the operator. However, when only the combination of the α-diketone compound and the tertiary amine compound is used as a photoinitiator, it shows high sensitivity not only to the irradiated light but also to the ambient light. Therefore, during operations such as filling, building up, and mounting, curing gradually progresses, the viscosity of the paste increases, and there is a problem that the operation becomes difficult.

[0018] In order to solve the above problems, when the addition amount of the photoinitiator is reduced or the addition amount of the polymerization inhibitor is increased, although the stability against ambient light is improved, the sensitivity to irradiation light is simultaneously decreased. Therefore, even when irradiated with irradiation light for a long time, sufficient curing does not proceed, the mechanical strength of the cured body decreases, or a large amount of the surface unpolymerized layer remains, causing problems such as coloring over time in the oral cavity. As yet another problem, when a tertiary amine compound is blended as a polymerization accelerator, there has been a problem that the cured body easily discolors when exposed to sunlight or the like. When used as a dental adhesive, there have been problems such as a decrease in adhesive strength when a heat load assumed in the oral cavity is applied and discoloration of the adhesive layer after curing. Thus, it has been difficult to achieve both characteristics such as environmental light stability and high polymerization activity with respect to irradiation light.

[0019] As a photoinitiator, a photoinitiator comprising a specific aryliodonium salt, a sensitizer, and an electron donor compound has been proposed, but sufficient physical properties could not be obtained. The photoinitiator containing an aryliodonium salt has the following problems. First, conventional aryliodonium salts have low solubility in polymerizable monomers, and assuming the use temperature in clinical practice, they are limited to extremely low concentrations due to the risk of precipitation or the like. Therefore, the photo-polymerization activity was insufficient. Furthermore, when an aryliodonium salt and a polymerization accelerator such as a tertiary amine compound are used in combination, the photosensitivity increases, so the stability against ambient light is low, the operable time is significantly shortened, and the discoloration of the cured body when exposed to sunlight or the like is more promoted, which has been a problem. Although the detailed promotion mechanism for discoloration is unclear, it is presumed that the discoloration is promoted by the formation of a salt or interaction between the cation moiety contained in the structure of the polymerization accelerator such as a tertiary amine compound or an organometallic compound and the photoacid generator.

[0020] However, according to the studies of the present inventors, in a dental photocurable composition, when a photoinitiator containing an aryliodonium salt having a specific structure is used, the solubility in a polymerizable monomer is improved, there is no risk of precipitation, etc., appropriate photosensitivity is exhibited, and furthermore, it has been found that discoloration when exposed to sunlight or the like is significantly reduced, and thus the present invention has been completed.

[0021] As described above, there is provided a dental photocurable composition that exhibits high polymerization activity with respect to irradiation light, and has aesthetic properties and mechanical properties (hardness, flexural strength, compressive strength, etc.) when applied to, for example, a composite resin for dental filling or a dental resin cement, and has durable adhesive strength when applied as an adhesive, and is excellent in long-term storage stability, environmental light stability, and color tone stability.

[0022] <(a) Polymerizable monomer> The (a) polymerizable monomer that can be used in the present invention can be used without any limitation from known monofunctional and / or polyfunctional polymerizable monomers generally used in the dental field. Exemplifying typical ones generally preferably used, they are (meth)acrylate monomers or (meth)acryloyl polymerizable monomers having an acryloyl group and / or a methacryloyl group. In the present invention, (meth)acrylate or (meth)acryloyl is used to comprehensively represent both acryloyl group-containing polymerizable monomers and methacryloyl group-containing polymerizable monomers.

[0023] Specific examples of the (meth)acrylate polymerizable monomer that can be used as the (a) polymerizable monomer are as follows. Examples of the monofunctional monomer include (meth)acrylic acid esters such as methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate (n-butyl (meth)acrylate, i-butyl (meth)acrylate), hexyl (meth)acrylate, dicyclopentenyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, glycidyl (meth)acrylate, lauryl (meth)acrylate, cyclohexyl (meth)acrylate, benzyl (meth)acrylate, allyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, glycerol (meth)acrylate, isobornyl (meth)acrylate; silane compounds such as γ-(meth)acryloyloxypropyltrimethoxysilane, γ-(meth)acryloyloxypropyltriethoxysilane; and nitrogen-containing compounds such as 2-(N,N-dimethylamino)ethyl (meth)acrylate, N-methylol (meth)acrylamide, diacetone (meth)acrylamide.

[0024] Examples of the aromatic difunctional monomer include 2,2-bis(4-(meth)acryloyloxyphenyl)propane, 2,2-bis(4-(3-(meth)acryloyloxy-2-hydroxypropoxy)phenyl)propane, 2,2-bis(4-(meth)acryloyloxyethoxyphenyl)propane, 2,2-bis(4-(meth)acryloyloxydiethoxyphenyl)propane, 2,2-bis(4-(meth)acryloyloxytetraethoxyphenyl)propane, 2,2-bis(4-(meth)acryloyloxypentaethoxyphenyl)propane, 2,2-bis(4-(meth)acryloyloxydipropoxyphenyl)propane, 2(4-(meth)acryloyloxyethoxyphenyl)-2(4-(meth)acryloyloxydiethoxyphenyl)propane, 2(4-(meth)acryloyloxydiethoxyphenyl)-2(4-(meth)acryloyloxytriethoxyphenyl)propane, 2(4-(meth)acryloyloxydipropoxyphenyl)-2(4-(meth)acryloyloxytriethoxyphenyl)propane, 2,2-bis(4-(meth)acryloyloxydipropoxyphenyl)propane, 2,2-bis(4-(meth)acryloyloxyisopropoxyphenyl)propane, and the like.

[0025] Examples of the aliphatic difunctional monomer include 2-hydroxy-3-acryloyloxypropyl methacrylate, hydroxypivalic acid neopentyl glycol di(meth)acrylate, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, butylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, propylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, 1,3-butanediol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, glycerol di(meth)acrylate, and the like.

[0026] Examples of trifunctional monomers include trimethylolpropane tri(meth)acrylate, trimethylolethane tri(meth)acrylate, trimethylolmethane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, and the like.

[0027] Examples of tetrafunctional monomers include pentaerythritol tetra(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, and the like.

[0028] Examples of urethane-based polymerizable monomers include di(meth)acrylates having a bifunctional or higher-functional urethane bond derived from an adduct of a polymerizable monomer having a hydroxyl group such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-chloro-2-hydroxypropyl (meth)acrylate, and a diisocyanate compound such as methylcyclohexane diisocyanate, methylene bis(4-cyclohexyl isocyanate), hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, isophorone diisocyanate, diisocyanate methyl methylbenzene, 4,4-diphenylmethane diisocyanate.

[0029] There is no restriction on using an oligomer or prepolymer having at least one or more polymerizable groups in the molecule other than these (meth)acrylate polymerizable monomers. Also, there is no problem even if a substituent such as a fluoro group is present in the same molecule. The polymerizable monomers described above can be used alone or in combination of two or more.

[0030] (a) The polymerizable monomer contained in the dental photocurable composition of the present invention may include a polymerizable monomer containing an acidic group known for imparting adhesiveness to dentin and prosthetic devices. Specific examples of the acidic group contained in the polymerizable monomer containing an acidic group include a phosphate group, a pyrophosphate group, a phosphonic acid group, a carboxylic acid group, a sulfonic acid group, a thiophosphate group, etc., and refer to a polymerizable monomer having at least one of these, preferably 10-methacryloyloxydecyl dihydrogen phosphate, or 6-methacryloxyhexyl phosphonoacetate or 4-methacryloxyethyl trimellitic acid. From the viewpoint of imparting adhesiveness, the blending amount may be 5 to 60 parts by weight, more preferably 10 to 50 parts by weight, out of 100 parts by weight of the total amount of the polymerizable monomer in the composition.

[0031] The dental photocurable composition of the present invention may contain a silane coupling agent to impart adhesiveness to glass ceramics. Any known silane coupling agent can be used without limitation, and 3-methacryloxypropyltrimethoxysilane may be used. From the viewpoint of imparting adhesiveness, the blending amount may be 0.5 to 10 parts by weight, out of 100 parts by weight of the total amount of the polymerizable monomer in the composition, and for example, it may be 0.5 to 5 parts by weight.

[0032] <(b) Filler> (b) The filler that can be used in the present invention can be any known filler generally used in dental composite materials.

[0033] (b) Examples of the types of fillers include inorganic fillers, organic fillers, organic-inorganic composite fillers, etc., and they can be used not only alone but also in combination of a plurality regardless of the type of filler.

[0034] The filler is not particularly limited, and examples include silica glass, fluoroaluminosilicate glass, fluoroaluminoborosilicate glass, other silicate glasses, and zirconium silicate glass containing zirconia, and among them, zirconium silicate may be used.

[0035] The above-mentioned (b) filler can be treated with a surface treatment material typified by a silane coupling material for the purpose of improving the affinity with the polymerizable monomer, the dispersibility in the polymerizable monomer, the mechanical strength and water resistance of the cured body. Such a surface treatment material and surface treatment method are not particularly limited, and known methods can be adopted without limitation. Examples of the silane coupling material used for the surface treatment of the filler include methyltrimethoxysilane, methyltriethoxysilane, methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, vinyltrichlorosilane, vinyltriethoxysilane, vinyltris(β-methoxyethoxy)silane, γ-methacryloyloxypropyltrimethoxysilane, γ-chloropropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, or hexamethyldisilazane. In addition to the silane coupling material, the surface treatment of the filler can be performed by a method using a titanate-based coupling material or an aluminate-based coupling material. The amount of the surface treatment material used for the filler is preferably 0.01 to 30 parts by weight, more preferably 0.5 to 20 parts by weight, based on 100 parts by weight of the filler before treatment.

[0036] The shape of the filler is not particularly limited, and amorphous and spherical fillers can be used. The average particle diameter of the filler preferably has an average particle diameter in the range of 0.01 μm to 50 μm, more preferably 0.1 μm to 30 μm, still more preferably 0.5 μm to 20 μm, and even more preferably 0.5 μm to 10 μm.

[0037] (a) With respect to 100 parts by mass of the polymerizable monomer, the blending amount of (b) the filler is preferably 10 to 1900 parts by weight, more preferably 30 to 900 parts by weight, and still more preferably 100 to 900 parts by weight. When blending more than 1900 parts by weight, the paste properties of the composition become hard and difficult to handle.

[0038] <(c) Photoinitiator> <(c-1) Photosensitizer> The (c-1) photosensitizer used in the dental photocurable composition of the present invention is not particularly limited, and known compounds generally used in the dental field can be used without any limitation.

[0039] Specific examples of the photosensitizer include α-diketones such as benzyl, camphorquinone, α-naphthyl, acetonaphthacene, p,p'-dimethoxybenzyl, p,p'-dichlorobenzylacetyl, pentanedione, 1,2-phenanthrenequinone, 1,4-phenanthrenequinone, 3,4-phenanthrenequinone, 9,10-phenanthrenequinone, naphthoquinone; benzoin alkyl ethers such as benzoin, benzoin methyl ether, benzoin ethyl ether; thioxanthones such as thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2-isopropylthioxanthone, 2-methoxythioxanthone, 2-hydroxythioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone; benzophenones such as benzophenone, p-chlorobenzophenone, p-methoxybenzophenone; acylphosphine oxides such as 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide; α-aminoacetophenones such as 2-benzyl-dimethylamino-1-(4-morpholinophenyl)-butanone-1, 2-benzyl-diethylamino-1-(4-morpholinophenyl)-propanone-1; ketals such as benzyldimethyl ketal, benzyldiethyl ketal, benzyl(2-methoxyethyl ketal); titanocenes such as bis(cyclopentadienyl)-bis[2,6-difluoro-3-(1-pyrrolyl)phenyl]-titanium, bis(cyclopentadienyl)-bis(pentafluorophenyl)-titanium, bis(cyclopentadienyl)-bis(2,3,5,6-tetrafluoro-4-disyloxyphenyl)-titanium, etc.

[0040] The (c-1) photosensitizer to be used can be appropriately selected according to the wavelength, intensity, light irradiation time of the light used for polymerization, and the types and blending amounts of other components to be combined. Further, the photosensitizer can be used alone or in combination of two or more. Among them, an α-diketone compound having a maximum absorption wavelength in the visible light region is preferably used, and particularly camphorquinone may be used.

[0041] Generally, the blending amount of the (c-1) photosensitizer is preferably 0.01 to 5 parts by weight, more preferably 0.05 to 3 parts by weight, and still more preferably 0.1 to 1 part by weight based on 100 parts by weight of the total amount of the (a) polymerizable monomer. When the blending amount of the photosensitizer is less than 0.01 part by weight, the polymerization activity with respect to the irradiated light is poor and the curing is insufficient. When blended in an amount more than 5 parts by weight, although sufficient curability is obtained, the environmental light stability becomes short and the yellowness increases.

[0042] <(c-2) Polymerization accelerator> The (c-2) polymerization accelerator used in the dental adhesive composition of the present invention is not particularly limited as long as it has a polymerization accelerating ability, and known polymerization accelerators generally used in the dental field can be used without any limitation. As the polymerization accelerator, tertiary amine compounds such as aromatic tertiary amine compounds and aliphatic tertiary amine compounds, and organometallic compounds can be used.

[0043] Specific examples of the above aromatic tertiary amine compounds include N,N-dimethylaniline, N,N-diethylaniline, N,N-di-n-butylaniline, N,N-dibenzylaniline, p-N,N-dimethyl-toluidine, m-N,N-dimethyl-toluidine, p-N,N-diethyl-toluidine, p-bromo-N,N-dimethylaniline, m-chloro-N,N-dimethylaniline, p-dimethylaminobenzaldehyde, p-dimethylaminoacetophenone, p-dimethylaminobenzoic acid, p-dimethylaminobenzoic acid ethyl ester, p-dimethylaminobenzoic acid amino ester, N,N-dimethylanthranilic acid methyl ester, N,N-dihydroxyethylaniline, p-N,N-dihydroxyethyl-toluidine, p-dimethylaminophenyl alcohol, p-dimethylaminostyrene, N,N-dimethyl-3,5-xylidine, 4-dimethylaminopyridine, N,N-dimethyl-α-naphthylamine, N,N-dimethyl-β-naphthylamine, and the like. Further, for example, it may be p-N,N-dimethyl-toluidine or p-N,N-dihydroxyethyl-toluidine.

[0044] Specific examples of the above aliphatic tertiary amine compounds include tributylamine, tripropylamine, triethylamine, triethanolamine, N-methyldiethanolamine, N-ethyldiethanolamine, N,N-dimethylhexylamine, N,N-dimethyldodecylamine, N,N-dimethylstearylamine, N,N-dimethylaminoethyl methacrylate, N,N-diethylaminoethyl methacrylate, 2-(N,N-diisopropylamino)ethyl methacrylate, 2,2'-(n-butylimino)diethanol, N-[3-(dimethylamino)propyl]acrylamide, and the like. Further, for example, it may be N,N-dimethylaminoethyl methacrylate, N,N-diethylaminoethyl methacrylate or triethanolamine.

[0045] The above organometallic compound is an organometallic compound containing scandium (Sc), titanium (Ti), vanadium (V), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), tin (Sn), zinc (Zn), zirconia (Zr), and preferably an organometallic compound containing tin (Sn), vanadium (V), copper (Cu). Specifically, examples of the organometallic compound containing tin (Sn) include dibutyl-tin-diacetate, dibutyl-tin-dimaleate, dioctyl-tin-dimaleate, dioctyl-tin-dilaurate, dibutyl-tin-dilaurate, dioctyl-tin-diversate, dioctyl-tin-S,S'-bis-isooctyl mercaptoacetate, tetramethyl-1,3-diacetoxydistannoxane, etc. Examples of the organometallic compound containing vanadium (V) include vanadium acetylacetonate, vanadium dioxide, vanadyl acetylacetonate, vanadium stearate, vanadyl oxalate, vanadyl sulfate, vanadium oxobis(1-phenyl-1,3-butanedionate), vanadium bis(maltolate), vanadium pentoxide, sodium metavanadate, etc. Examples of the organometallic compound containing copper (Cu) include copper acetylacetonate, copper naphthenate, copper octylate, copper stearate, copper acetate.

[0046] The type of the (c-2) polymerization accelerator used can be appropriately selected according to the types and blending amounts of other components to be combined. In addition, the polymerization accelerator can be used alone or in combination of two or more kinds.

[0047] Usually, the blending amount of the (c-2) polymerization accelerator is preferably 0.01 to 10 parts by weight, more preferably 0.05 to 5 parts by weight, based on 100 parts by weight of the total amount of the (a) polymerizable monomer. When the blending amount of the polymerization accelerator is less than 0.01 part by weight, the polymerization accelerating ability is poor and curing is likely to be insufficient. When more than 10 parts by weight is blended, although sufficient curability is obtained, the environmental light stability is shortened and the discoloration of the cured product increases.

[0048] <(c-3) Aryliodonium salt> The (c-3) aryliodonium salt used in the dental adhesive composition of the present invention is an aryliodonium salt represented by the formula (1).

[0049]

Chemical formula

[0050] R1 in the formula (1) represents an organic group bonded to I, and R1 may be the same or different. Examples of R1 include an aryl group having 6 to 30 carbon atoms, a heterocyclic group having 4 to 30 carbon atoms, an alkyl group having 1 to 30 carbon atoms, an alkenyl group having 2 to 30 carbon atoms, or an alkynyl group having 2 to 30 carbon atoms, and these may be substituted with at least one selected from the group consisting of alkyl, hydroxy, alkoxy, alkylcarbonyl, arylcarbonyl, alkoxycarbonyl, aryloxycarbonyl, arylthiocarbonyl, acyloxy, arylthio, alkylthio, aryl, heterocycle, aryloxy, alkylsulfinyl, arylsulfinyl, alkylsulfonyl, arylsulfonyl, alkyleneoxy, amino, cyano, nitro groups, and halogen.

[0051] In the above, examples of the aryl group having 6 to 30 carbon atoms include monocyclic aryl groups such as a phenyl group, and condensed polycyclic aryl groups such as naphthyl, anthracenyl, phenanthrenyl, pyrenyl, chrysenyl, naphthacenyl, benzanthracenyl, anthraquinolyl, fluorenyl, naphthoquinone, and anthraquinone.

[0052] ​Examples of the complex cyclic group having 4 to 30 carbon atoms include cyclic groups containing 1 to 3 heteroatoms such as oxygen, nitrogen, and sulfur. These may be the same or different. Specific examples include monocyclic complex cyclic groups such as thienyl, furanyl, pyranyl, pyrrolyl, oxazolyl, thiazolyl, pyridyl, pyrimidyl, pyrazinyl, and condensed polycyclic complex cyclic groups such as indolyl, benzofuranyl, isobenzofuranyl, benzothienyl, isobenzothienyl, quinolinyl, isoquinolinyl, quinoxalinyl, quinazolinyl, carbazolyl, acridinyl, phenothiazinyl, phenazinyl, xanthenyl, thianthrenyl, phenoxazinyl, phenoxathiinyl, chromanyl, isochromanyl, dibenzothienyl, xanthonyl, thioxanthonyl, dibenzofuranyl.

[0053] Examples of the alkyl group having 1 to 30 carbon atoms include linear alkyl groups such as methyl, ethyl, propyl, butyl, hexadecyl, octadecyl, branched alkyl groups such as isopropyl, isobutyl, sec-butyl, tert-butyl, isopentyl, neopentyl, tert-pentyl, isohexyl, and cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl. Examples of the alkenyl group having 2 to 30 carbon atoms include linear or branched ones such as vinyl, allyl, 1-propenyl, isopropenyl, 1-butenyl, 2-butenyl, 3-butenyl, 1-methyl-1-propenyl. Further, examples of the alkynyl group having 2 to 30 carbon atoms include linear or branched ones such as ethynyl, 1-propynyl, 2-propynyl, 1-butynyl, 2-butynyl, 3-butynyl, 1-methyl-1-propynyl, 1-methyl-2-propynyl.

[0054] The above aryl group having 6 to 30 carbon atoms, heterocyclic group having 4 to 30 carbon atoms, alkyl group having 1 to 30 carbon atoms, alkenyl group having 2 to 30 carbon atoms or alkynyl group having 2 to 30 carbon atoms may have at least one substituent. Examples of the substituent include linear alkyl groups having 1 to 18 carbon atoms such as methyl, ethyl, propyl, butyl, octadecyl; branched alkyl groups having 1 to 18 carbon atoms such as isopropyl, isobutyl, sec-butyl, tert-butyl; cycloalkyl groups having 3 to 18 carbon atoms such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl; hydroxy group; linear or branched alkoxy groups having 1 to 18 carbon atoms such as methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, sec-butoxy, tert-butoxy, dodecyloxy; linear or branched alkylcarbonyl groups having 2 to 18 carbon atoms such as acetyl, propionyl, butanoyl, 2-methylpropionyl, heptanoyl, 2-methylbutanoyl, 3-methylbutanoyl, octanoyl; arylcarbonyl groups having 7 to 11 carbon atoms such as benzoyl, naphthoyl; linear or branched alkoxycarbonyl groups having 2 to 19 carbon atoms such as methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, isopropoxycarbonyl, butoxycarbonyl, isobutoxycarbonyl, sec-butoxycarbonyl, tert-butoxycarbonyl; aryloxycarbonyl groups having 7 to 11 carbon atoms such as phenoxycarbonyl, naphthoxycarbonyl; arylthiocarbonyl groups having 7 to 11 carbon atoms such as phenylthiocarbonyl, naphthoxythiocarbonyl; linear or branched acyloxy groups having 2 to 19 carbon atoms such as acetoxy, ethylcarbonyloxy, propylcarbonyloxy, isobutylcarbonyloxy, sec-butylcarbonyloxy, tert-butylcarbonyloxy, octadecylcarbonyloxy;Phenylthio, biphenylylthio, methylphenylthio, chlorophenylthio, bromophenylthio, fluorophenylthio, hydroxyphenylthio, methoxyphenylthio, naphthylthio, 4-[4-(phenylthio)benzoyl]phenylthio, 4-[4-(phenylthio)phenoxy]phenylthio, 4-[4-(phenylthio)phenyl]phenylthio, 4-(phenylthio)phenylthio, 4-benzoylphenylthio, 4-benzoyl-chlorophenylthio, 4-benzoyl-methylthiophenylthio, 4-(methylthiobenzoyl)phenylthio, 4-(p-tert-butylbenzoyl)phenylthio and other arylthio groups having 6 to 20 carbon atoms; straight-chain or branched alkylthio groups having 1 to 18 carbon atoms such as methylthio, ethylthio, propylthio, tert-butylthio, neopentylthio, dodecylthio; aryl groups having 6 to 10 carbon atoms such as phenyl, tolyl, dimethylphenyl, naphthyl; heterocyclic groups having 4 to 20 carbon atoms such as thienyl, furanyl, pyranyl, xanthenyl, chromanyl, isochromanyl, xanthonyl, thioxanthonyl, dibenzofuranyl; aryloxy groups having 6 to 10 carbon atoms such as phenoxy, naphthyloxy; straight-chain or branched alkylsulfinyl groups having 1 to 18 carbon atoms such as methylsulfinyl, ethylsulfinyl, propylsulfinyl, tert-pentylsulfinyl, octylsulfinyl; arylsulfinyl groups having 6 to 10 carbon atoms such as phenylsulfinyl, tolylsulfinyl, naphthylsulfinyl; straight-chain or branched alkylsulfonyl groups having 1 to 18 carbon atoms such as methylsulfonyl, ethylsulfonyl, propylsulfonyl, isopropylsulfonyl, butylsulfonyl, octylsulfonyl; arylsulfonyl groups having 6 to 10 carbon atoms such as phenylsulfonyl, tolylsulfonyl (tosyl group), naphthylsulfonyl; alkyleneoxy group; cyano group; nitro group; halogens such as fluorine, chlorine, bromine, iodine, etc. are included.;

[0055] In formula (1), R2 represents an alkyl group substituted with a fluorine atom, and the number of carbon atoms may be 1 to 4. Specific examples of the alkyl group include linear alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, octyl; branched alkyl groups such as isopropyl, isobutyl, sec-butyl, tert-butyl; and further cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl. R2 may be an alkyl group in which 80% or more of the hydrogen atoms are substituted with fluorine atoms. Further, R2 may be an alkyl group in which 90% or more of the hydrogen atoms are substituted with fluorine atoms. Further, R2 may be an alkyl group in which 100% or more of the hydrogen atoms are substituted with fluorine atoms. When the hydrogen atoms in the alkyl group are not substituted with fluorine atoms, discoloration occurs after exposure to sunlight or the like.

[0056] By incorporating the aryliodonium salt represented by formula (1), suppression of discoloration after exposure and sufficient pot life under ambient light are ensured. Although this mechanism is not bound by a specific theory of the present invention, the following is presumed. The introduction of an alkyl group substituted with a fluorine atom increases the hydrophobicity of the aryliodonium salt. This is also the case in the excited state, and the interaction between the excited-state aryliodonium salt and the polymerization accelerator decreases. Therefore, when the aryliodonium salt itself is excited or is in an excited state by the energy obtained from a photosensitizer, the energy or electron transfer to the polymerization accelerator is suppressed, which is presumed to lead to suppression of discoloration after exposure to sunlight or the like and ensuring sufficient pot life under ambient light.

[0057] Particularly preferred R2 is a linear or branched alkyl group having 1 to 4 carbon atoms and in which all hydrogen atoms in the alkyl group are substituted with fluorine atoms. Specific examples include CF 3 、CF 3 CF 2 、(CF 3 ) 2 CF、CF 3 CF 2 CF 2 、CF 3 CF 2 CF2 CF 2 、(CF 3 ) 2 CFCF 2 、CF 3 CF 2 (CF 3 )CF、(CF 3 ) 3 Examples include C.

[0058] In formula (1), the number b of R2 is an integer from 1 to 5, preferably from 2 to 4, and particularly preferably 2 or 3. The b R2s may be the same or different from each other.

[0059] Specific examples of preferred anion moieties include [(CF 3 CF 2 ) 3 PF 3 - 、[(CF 3 CF 2 CF 2 ) 3 PF 3 - 、[((CF 3 ) 2 CF) 3 PF 3 - 、[((CF 3 ) 2 CF) 2 PF 4 - 、[((CF 3 ) 2 CFCF 2 ) 3 PF 3 - and [((CF 3 ) 2 CFCF 2 ) 2 PF 4 -.

[0060] ​​​​​The aryliodonium salts represented by formula (1) are excellent in solubility in polymerizable monomers and polymerization promoting ability, and include diphenyliodonium tris(pentafluoroethyl) trifluorophosphate, ditolyliodonium tris(pentafluoroethyl) trifluorophosphate, bis(4-dodecylphenyl)iodonium tris(pentafluoroethyl) trifluorophosphate, bis(4-methoxyphenyl)iodonium, (4-octyloxyphenyl)phenyliodonium tris(pentafluoroethyl) trifluorophosphate, bis(4-decyloxy)phenyliodonium tris(pentafluoroethyl) trifluorophosphate, 4-(2-hydroxytetradecyloxy)phenylphenyliodonium tris(pentafluoroethyl) trifluorophosphate, 4-isopropylphenyl(p-tolyl)iodonium tris(pentafluoroethyl) trifluorophosphate, 4-isobutylphenyl(p-tolyl)iodonium tris(pentafluoroethyl) trifluorophosphate, bis(4-tert-butylphenyl)iodonium tris(pentafluoroethyl) trifluorophosphate, and bis(4-tert-butylphenyl)iodonium tris(pentafluoropropyl) trifluorophosphate.

[0061] Generally, the blending amount of the (c-3) aryliodonium salt is preferably 0.01 to 10 parts by weight, more preferably 0.05 to 5 parts by weight, and may be, for example, 0.5 to 3 parts by weight, based on 100 parts by weight of the total amount of the (a) polymerizable monomer. When the blending amount of the aryliodonium salt is less than 0.01 part by weight, the polymerization promoting ability is poor and the curing is insufficient. When blended in an amount more than 10 parts by weight, although sufficient curability is achieved, the environmental light stability becomes short and discoloration such as the cured product turning brown increases.

[0062] These photoinitiators can be used alone or in combination of two or more. Further, these polymerization initiators may be subjected to secondary treatments such as encapsulation in microcapsules as necessary, without any problems. Furthermore, these various types of photoinitiators can be used alone or in combination of two or more, regardless of the polymerization mode or polymerization method.

[0063] In the dental photocurable composition of the present invention, a chemical polymerization initiator may be blended in addition to (c) the photoinitiator, and known chemical polymerization initiators can be used without limitation. As the chemical polymerization initiator, a thiourea derivative, an organic peroxide having a hydroperoxide group, or a sulfinate can be used alone or in combination.

[0064] Any known thiourea derivative can be used without limitation as the thiourea derivative. Specific examples of the thiourea derivative include dimethylthiourea, diethylthiourea, tetramethylthiourea, (2-pyridyl)thiourea, N-methylthiourea, ethylenethiourea, N-allylthiourea, N-allyl-N'-(2-hydroxyethyl)thiourea, N-benzylthiourea, 1,3-dicyclohexylthiourea, N,N'-diphenylthiourea, 1,3-di(p-tolyl)thiourea, 1-methyl-3-phenylthiourea, N-acetylthiourea, N-benzoylthiourea, diphenylthiourea, dicyclohexylthiourea, and the like. Among these, N-acetylthiourea or N-benzoylthiourea may be used. These thiourea derivatives may be used in combination of a plurality of types as necessary. The blending amount of the thiourea derivative is preferably 0.1 to 4 parts by weight based on the total amount of all the polymerizable monomers. If it is less than 0.1 part by weight, the polymerization promoting ability is insufficient, and if it exceeds 4 parts by weight, the storage stability may decrease in some cases.

[0065] As the organic peroxide having a hydroperoxide group, any known organic peroxide having a hydroperoxide group can be used without limitation. Specific examples of the organic peroxide include t-butyl hydroperoxide, cyclohexyl hydroperoxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, p-menthane hydroperoxide, diisopropylbenzene hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, etc. From the viewpoint of reactivity, cumene hydroperoxide may be used. These organic peroxides may be used in combination of a plurality of types as necessary. The compounding amount of the organic peroxide having a hydroperoxide group is preferably 0.1 to 4 parts by weight based on the total amount of all polymerizable monomers. If it is less than 0.1 part by weight, the ability as a polymerization accelerator is insufficient, and if it exceeds 4 parts by weight, the storage stability may decrease.

[0066] Examples of the sulfinic acid derivative include salts (which may be alkali metals or alkaline earth metals) of p-toluenesulfinic acid, benzenesulfinic acid, 2,4,6-trimethylbenzenesulfinic acid, 2,4,6-triethylbenzenesulfinic acid, 2,4,6-triisopropylbenzenesulfinic acid, etc. Specific examples of the salt compounds of these sulfinic acids include sodium p-toluenesulfinate or sodium benzenesulfinate.

[0067] <(d) Solvent> The (d) solvent that can be used in the present invention can be used without any limitation as long as it is a known solvent used in the dental field. Exemplary representative solvents that are preferably used include water and organic solvents. Among the organic solvents, water-soluble volatile organic solvents having a boiling point of 100°C or lower under normal pressure are preferred. Specific examples thereof include ethanol, methanol, 1-propanol, isopropyl alcohol, acetone, methyl ethyl ketone, 1,2-dimethoxyethane, 1,2-diethoxyethane, and tetrahydrofuran. Particularly preferred are water, acetone, and ethanol. The blending amount of the (d) solvent may be 1 to 300 parts by weight, for example, 50 to 300 parts by weight, or 100 to 250 parts by weight based on the total amount of all polymerizable monomers.

[0068] <Other components> In addition, the dental photocurable composition of the present invention may contain components other than the components (a) to (d) above as long as the effects of the present invention are not inhibited. For example, excipients typified by fumed silica, ultraviolet absorbers such as benzophenone-based and benzotriazole-based compounds, polymerization inhibitors such as hydroquinone, hydroquinone monomethyl ether, and 2,5-di-tert-butyl-4-methylphenol, α-alkylstyrene compounds, mercaptan compounds such as n-butyl mercaptan and n-octyl mercaptan, chain transfer agents such as terpenoid compounds such as limonene, myrcene, α-terpinene, β-terpinene, γ-terpinene, terpinolene, β-pinene, and α-pinene, metal scavengers such as aminocarboxylic acid-based chelating agents and phosphonic acid-based chelating agents, discoloration preventives, antibacterial agents, coloring pigments, water, solvents that can be mixed with water in an arbitrary ratio, and other components such as conventionally known additives can be optionally added as needed.

[0069] The method for preparing the dental photocurable composition of the present invention is not particularly limited. As a general production method for dental photocurable compositions, after preparing a binder resin in which (a) a polymerizable monomer and (c) a photoinitiator are previously mixed, this binder resin is kneaded with (b) a filler, and air bubbles are removed under vacuum to prepare a uniform paste-like composition. Or a method of mixing (a) a polymerizable monomer, (c) a photoinitiator, and (d) a solvent to prepare a homogeneous liquid composition. Also in the present invention, it can be produced without any problem by the above production method.

Industrial Applicability

[0070] In the dental field, dental photocurable compositions are used for oral treatments, and are applicable to dental adhesives, dental composite resins, dental abutment building materials, dental resin cements, dental surface coatings, dental pit and fissure sealants, dental manicure materials, etc., so there is industrial applicability.

Examples

[0071] Examples of the present invention will be specifically described below, but the present invention is not limited to these examples.

[0072] The materials used in the examples and comparative examples and their abbreviations are shown below. 〔(a) Polymerizable monomer〕 ·Bis-GMA: 2,2-bis[4-(3-methacryloyloxy-2-hydroxypropoxy)phenyl]propane ·2.6E: 2,2-bis(4-(meth)acryloyloxypolyethoxyphenyl)propane with an average addition mole number of 2.6 of ethoxy groups ·UDMA: N,N-(2,2,4-trimethylhexamethylene)bis[2-(aminocarboxy)ethanol]methacrylate ·TEGDMA: Triethylene glycol dimethacrylate ·GDMA: Glycerol dimethacrylate ·2-HEMA: 2-Hydroxyethyl methacrylate ·MDP: 10-Methacryloyloxydecyl dihydrogen phosphate ·6-MHPA: 6-Methacryloxyhexyl phosphonoacetate ·4-MET: 4-Methacryloxyethyl trimellitate

[0073] [(c) Polymerization initiator] (c-1) Photosensitizer ·CQ: α-Camphorquinone

[0074] (c-2) Polymerization accelerator Aromatic tertiary amine compound ·DMBE: Ethyl N,N-dimethylaminobenzoate Aliphatic tertiary amine compound ·DMAEMA: N,N-Dimethylaminoethyl methacrylate Organometallic compound ·SnL: Dioctyl-tin-dilaurate

[0075] (c-3) Diaryliodonium salt ·IPIFP: 4-Isopropylphenyl(p-tolyl)iodonium tris(pentafluoroethyl)trifluorophosphate

[0076] [Chemical formula] ·tBIFP: Bis(4-tert-butylphenyl)iodonium tris(pentafluoropropyl)trifluorophosphate

[0077] [Chemical formula] ·DPIHP: Diphenyliodonium hexafluorophosphate

[0078] (d) Solvent ·Water ·Acetone

[0079] [(b) Filler] The manufacturing methods of each filler used in the preparation of the dental photocurable composition are shown below.

[0080] To 100.0 g of a zirconium silicate filler (average particle size 2.2 μm: 90 wt% zirconia, 10 wt% silica), 50.0 g of water, 35.0 g of ethanol, and 3.0 g of 3-methacryloyloxypropyltrimethoxysilane as a silane coupling material were added, and the resulting silane coupling treatment liquid was stirred at room temperature for 2 hours and then stirred and mixed for 30 minutes. Thereafter, heat treatment was performed at 140 °C for 15 hours to obtain Filler 1.

[0081] To 100.0 g of a zirconium silicate filler (average particle size 0.8 μm: 85 wt% zirconia, 15 wt% silica), 50.0 g of water, 35.0 g of ethanol, and 5.0 g of 3-methacryloyloxypropyltrimethoxysilane as a silane coupling material were added, and the resulting silane coupling treatment liquid was stirred at room temperature for 2 hours and then stirred and mixed for 30 minutes. Thereafter, heat treatment was performed at 140 °C for 15 hours to obtain Filler 2.

[0082] Chemical polymerization initiator Thiourea derivative ·BTU: N-benzoylthiourea Organic peroxide having a hydroperoxide group ·CHP: Cumene hydroperoxide

[0083] Ultraviolet absorber ·BT: 2-(2-Hydroxy-5-methylphenyl)benzotriazole Polymerization inhibitor ·BHT: 2,6-Di-t-butyl-4-methylphenol

[0084] 〈Method for producing a dental photocurable composition (composite resin for dental filling)〉 The polymerizable monomer (a), polymerization initiator (c), and others shown in Table 1 were mixed using a mix rotor VMRC-5 at 100 rpm for 24 hours to obtain a binder resin in which each material was uniformly dissolved. Thereafter, the binder resin and the filler (b) were put into a kneader, uniformly stirred, and then defoamed under vacuum to prepare the dental photocurable compositions of Examples 1 to 12 and Comparative Examples 1 to 2.

[0085]

Table 1

[0086] 〈Method for producing dental photocurable composition (dental resin cement)〉 The polymerizable monomer (a), polymerization initiator (c), and others shown in Table 2 were mixed using a mix rotor VMRC-5 at 100 rpm for 24 hours to obtain a binder resin in which each material was uniformly dissolved. Thereafter, the binder resin and the filler (b) were put into a kneader, uniformly stirred, and then defoamed under vacuum to obtain Pastes 1 and 2, which were then filled into a double syringe (5 mL) manufactured by Mix Pack to prepare the dental photocurable compositions of Examples 13 to 22 and Comparative Examples 3 to 4.

[0087]

Table 2

[0088] 〈Method for producing dental photocurable composition〉 The polymerizable monomer (a), polymerization initiator (c), and others shown in Table 3 were mixed using a mix rotor VMRC-5 at 100 rpm for 24 hours to prepare the dental photocurable compositions of Examples 23 to 28 and Comparative Examples 5 to 8.

[0089]

Table 3

[0090] 〈Method for producing dental photocurable composition (dental adhesive)〉 The polymerizable monomer (a), the photoinitiator (c), and the solvent (d) shown in Table 4 were mixed using a Turbler mixer T2F (manufactured by Shimadzu Enterprises) to prepare a homogeneous liquid dental photocurable composition, which was filled into a light-shielding plastic container to prepare the dental photocurable compositions of Examples 29 to 36 and Comparative Examples 9 to 10.

[0091] [Table 4]

[0092] The test methods employed in the examples and comparative examples are as follows. For the dental filling composite resin and the dental resin composition, samples were taken directly. For the dental resin cement, a paste obtained by mixing Paste 1 and Paste 2 using a mixing tip manufactured by Mixpac was used.

[0093] (1) Flexural strength After filling the prepared dental photocurable composition into a stainless steel mold, cover glasses were placed on both sides and pressed with a glass slab, and then light irradiation was performed 5 times for 10 seconds each using a photo-polymerization irradiator (Blue Shot: manufactured by Matsuura) to cure it. After curing, the cured product was taken out of the mold, and then the back surface was also irradiated with light in the same manner to obtain a test specimen (25×2×2 mm: rectangular parallelepiped). After immersing the test specimen in water at 37°C for 24 hours, a flexural test was conducted. The flexural test was performed using an Instron universal testing machine (manufactured by Instron) with a span of 20 mm and a crosshead speed of 1 mm / min.

[0094] (2) Environmental light stability Adjust the height of the dental lamp (manufactured by Morita Manufacturing Co., Ltd., Luna-Vue S) using an illuminance meter so that the light with an illuminance of 8000 ± 1000 lx hits the sample placement section. After placing a slide glass (26 × 16 mm, thickness 2 mm) on a glass slab covered with dull black paper, collect about 30 mg of the sample on it. After exposing the sample at the sample placement section for 60 ± 5 seconds, take out the sample from the sample placement section and immediately press another slide glass against the sample to form a thin layer. If the state of the sample at this time does not maintain a physically uniform state, it is determined that curing has started, and the time until curing is evaluated in 5-second increments. The longer this time is, the better the environmental light stability.

[0095] (3) Discoloration of the cured product a) Dental photo-curable composition (excluding dental adhesives) After filling the prepared dental photo-curable composition into a stainless steel mold (15φ × 1 mm: disc shape) respectively, place a cover glass from above and press it using a glass plate. Perform light irradiation for 1 minute using a photopolymerization irradiator (Grip Light II: manufactured by Matsuura) from above the cover glass to cure it. After taking out the cured product from the mold, remove the cover glass and measure the color tone of this specimen. For color measurement, place the specimen on the background of a standard white plate (D65 / 10° X = 81.07, Y = 86.15, Z = 93.38), and perform the measurement under predetermined fixed conditions (light source: C, viewing angle: 2°, measurement area: 11 mm) using a spectrocolorimeter (manufactured by BYK-Chemie). Then, after exposing the specimen to light for 24 hours using a xenon lamp light exposure tester (Sun Test CPS+), measure the color tone of the specimen again, and represent the difference in discoloration by ΔE calculated from the following formula. ΔE = {(ΔL*) 2 + (Δa*) 2 + (Δb*) 2} 1 / 2 ΔL* = L1* - L2* Δa* = a1* - a2* Δb* = b1* - b2* Here, L1* is the lightness index before light exposure, L2* is the lightness index after light exposure, a1*, b1* are the color quality indexes before light exposure, and a2*, b2* are the color quality indexes after light exposure. b) Dental photocurable composition (dental adhesive) A polyethylene frame with a thickness of 50 μm was fixed on a glass plate, the prepared dental photocurable composition was applied into the frame, and the operation of air-drying was repeated until the liquid surface stopped moving. When the thickness reached 50 μm or more, the glass plate was pressed against it, and light irradiation was performed for 1 minute using a photopolymerization irradiator (Grip Light II: manufactured by Matsuura) to cure it. After taking out the cured product from the frame, the cover glass was removed, and the color tone of this specimen was measured. For color measurement, the specimen was placed on the background of a standard white plate (D65 / 10° X = 81.07, Y = 86.15, Z = 93.38), and it was performed under predetermined constant conditions (light source: C, viewing angle: 2°, measurement area: 11 mm) using a spectrophotometer (manufactured by BYK-Chemie). Then, after immersing the specimen in water at 37°C for 2 months, the color tone of the specimen was measured again, and the difference in discoloration was expressed by ΔE calculated from the following formula. ΔE = {(ΔL*) 2 +(Δa*) 2 +(Δb*) 2} 1 / 2 ΔL* = L1* - L2* Δa* = a1* - a2* Δb* = b1* - b2* Here, L1* is the lightness index before immersion, L2* is the lightness index after immersion, a1*, b1* are the color quality indices before immersion, and a2*, b2* are the color quality indices after immersion.

[0096] (4) Evaluation of storage stability The prepared dental photocurable composition was stored in a thermostat set at 50°C under shielding. After 90 days, tests equivalent to the discoloration of the cured product in (3) and the precipitation of aryliodonium salt were confirmed. The storage stability was evaluated from the change over time between the initial value and the value after 90 days at 50°C. Regarding precipitation, the paste was discharged from the syringe, and the presence or absence of precipitates was confirmed. Those with no precipitation at all were designated as A, those with slight precipitation were designated as B, and those with obvious precipitation were designated as C. In addition, a dental photocurable composition without aryliodonium salt was prepared as a reference sample for each composition, and it was confirmed that there were no precipitates at all.

[0097] (5) Evaluation of Durable Adhesion Strength Cut the crown part of the extracted permanent mandibular central incisor of cattle, and embed the bovine tooth piece with epoxy resin. Under running water, expose the dentin with #600 waterproof abrasive paper, wash with water and dry. Stick a double-sided tape with a 4-mm diameter hole on the exposed dentin to define the bonding surface. Fix a plastic mold (inner diameter 4 mm, height 2 mm or 4 mm) on the defined surface, apply a dental curable composition to the bonding surface, and irradiate with light for 20 seconds using a photopolymerization irradiator (Grip Light II: manufactured by Matsuura) to cure. Then, fill the mold with a dental composite resin "Beauty Fill Flow Plus" (Matsuura Co., Ltd.), irradiate with light for 20 seconds again to cure. Remove the plastic mold to prepare an adhesion test specimen. After immersing this adhesion test specimen in distilled water at 37°C for 24 hours, use an Instron universal testing machine (Instron 5567, manufactured by Instron Corporation) to perform a dentin adhesion test based on shear adhesion strength at a crosshead speed of 1 mm / min, and measure the initial adhesion strength. In addition, after preparing an adhesion test specimen and immersing it in distilled water at 37°C for 24 hours, apply 10,000 thermal cycles (alternately immerse in 55°C for 30 seconds and 5°C for 30 seconds), and use the result of the dentin adhesion test as the durable adhesion strength.

[0098] 〔Examples 1 to 12〕 The dental photocurable compositions of Examples 1 to 12 exhibited high flexural strength, excellent environmental light stability, high stain resistance, and almost no decrease in stain resistance and precipitation even after 90 days at 50°C, showing excellent storage stability.

[0099] 〔Comparative Examples 1 to 2〕 The dental photocurable composition of Comparative Example 1 had low environmental light stability, significant discoloration, and precipitation of aryl iodonium salt was observed. It was confirmed that the dental photocurable composition of Comparative Example 2 had low flexural strength and significant discoloration.

[0100] The evaluation results of the dental photocurable compositions (dental resin cements) of the examples and comparative examples are shown in Table 5.

[0101]

Table 5

[0102] 〔Comparative Examples 3 - 4〕 The dental photocurable composition of Comparative Example 3 showed significant discoloration and precipitation of the aryliodonium salt was observed. It was confirmed that the dental photocurable composition of Comparative Example 4 had low flexural strength and significant discoloration.

[0103] The evaluation results of the dental photocurable compositions of the examples and comparative examples are shown in Table 6.

[0104]

Table 6

[0105] 〔Comparative Examples 5 - 8〕 The dental photocurable compositions of Comparative Examples 5 and 6 have low flexural strength and environmental light stability, and precipitation of the aryliodonium salt was observed after 90 days at 50°C. It was confirmed that the dental photocurable compositions of Comparative Examples 7 and 8 have low flexural strength, and furthermore, Comparative Example 8 has low environmental light stability.

[0106]

Table 7

[0107] 〔Examples 29 - 36〕 The dental photocurable compositions of Examples 29 to 36 have high adhesive strength, particularly high durable adhesiveness, no precipitation of aryl iodonium salt is observed even after 90 days at 50°C, the discoloration after immersion in water is extremely low, and they have excellent storage stability.

[0108] 〔Comparative Examples 9 and 10〕 The dental photocurable compositions of Comparative Examples 9 and 10 have low adhesive strength and color tone stability, and precipitation of aryl iodonium salt was observed after 90 days at 50°C. From these results, the effectiveness of the aryl iodonium salt having a specific structure was shown.

[0109]

Table 8

[0110] In the above examples, dental filling composite resins, dental resin cements, and dental adhesives have been described, but the present invention can be used without any limitation for other dental photocurable compositions.

Claims

1. (a) A polymerizable monomer; and (c-1) A photosensitizer, (c-2) A polymerization accelerator, and (c-3) A compound of formula (1): 【Chemical 1】 (In the formula, R1 represents an aryl group having 6 to 30 carbon atoms which may have at least one substituent and is bonded to I, R2 represents an alkyl group in which part of hydrogen atoms are substituted by fluorine atoms, b represents the number thereof, and is an integer of 1 to 5) an aryliodonium salt represented by contained in (c) a photoinitiator is included, wherein the (a) polymerizable monomer is a (meth)acrylate monomer or a (meth)acryloyl polymerizable monomer having an acryloyl group and / or a methacryloyl group, A dental photocurable composition.

2. The dental photocurable composition according to Claim 1, further comprising (b) a filler.

3. The (c) photoinitiator is with respect to 100 parts by mass of the (a) polymerizable monomer, (c-1) Photosensitizer: 0.1 to 5 parts by mass, (c-2) Polymerization accelerator: 0.01 to 10 parts by mass, and (c-3) Aryliodonium salt represented by formula (1): 0.01 to 10 parts by mass The dental photocurable composition according to Claim 1 or 2, which contains.

4. With respect to 100 parts by mass of the (a) polymerizable monomer, (b) The filler contains 10 to 1900 parts by weight The dental photocurable composition according to Claim 3, which contains.

5. A dental adhesive, a dental composite resin, a dental abutment building material, a dental resin cement, a dental surface coating material, a dental pit and fissure sealant, and / or a dental manicure material, which is the dental photocurable composition according to any one of Claims 1 to 4.

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