Optical hardening product for nails or artificial nails

Abstract

The invention proposes an optical hardening composition for nails or artificial nails, containing a polythiol compound and fumed silica, in which the composition allows both a high viscosity-to-texture ratio (high thixotropy) and high transparency (low opacity) of the hardened material to be achievable. The optical hardening composition for nails or artificial nails contains the following components (A) to (D): Component (A): a compound containing (met)acryloyl groups Component (B): a polythiol compound Component (C): an optical initiator Component (D): a filling agent containing component (D-1) and component (D-2); in which each component (D-1) and component (D-2) is surface-treated fumed silica with specific residues on their surfaces.

Description

Photocurable composition for nails or artificial nails

[0001] The present invention relates to a photocurable composition for nails or artificial nails, which contains a polythiol compound.

[0002] In the field of photocurable gel nails, it is known to add fumed silica to photocurable compositions for nails or artificial nails to enhance thixotropy (for example, JP 2010-013439 A).

[0003] However, when fumed silica is added to a photocurable composition for nails or artificial nails, thixotropy may not be exhibited depending on the types of raw materials contained in the composition or the combination of the raw materials and fumed silica. Furthermore, if the amount of fumed silica added is increased in order to increase thixotropy, the transparency of the cured product decreases.

[0004] As described above, in the past, it was difficult to achieve both a high structural viscosity ratio (high thixotropy) and high transparency (low turbidity) of the cured product when fumed silica was added to a photocurable composition for nails or artificial nails containing a polythiol compound.

[0005] Therefore, an object of the present invention is to provide a means for achieving both a high structural viscosity ratio (high thixotropy) and high transparency (low turbidity) of the cured product in a photocurable composition for nails or artificial nails containing a polythiol compound and fumed silica.

[0006] As a result of extensive research into achieving the above object, the present inventors have completed the present invention, which relates to a photocurable composition for nails or artificial nails.

[0007] The gist of the present invention will be described below. A first embodiment of the present invention is a photocurable composition for nails or artificial nails, comprising the following components (A) to (D): Component (A): a compound having a (meth)acryloyl group Component (B): a polythiol compound Component (C): a photoinitiator Component (D): a filler comprising components (D-1) and (D-2) Component (D-1): a surface-treated fumed silica, the surface residue of which is represented by the following formula 1:

[0008]

[0009] Here, n is an integer of 1 or more; Component (D-2): fumed silica that has been surface-treated, and whose surface residue is represented by the following formula 2.

[0010]

[0011] A second embodiment of the present invention is the photocurable composition for nail or artificial nail according to the first embodiment, wherein the mass ratio of the component (D-1) to the component (D-2) in the entire component (D) (component (D-1):component (D-2)) is 20:80 to 80:20.

[0012] A third embodiment of the present invention is the photocurable composition for nail or artificial nail according to the first or second embodiment, which contains 1.0 to 20.0 mass% of the component (D) based on the total mass of the composition.

[0013] A fourth embodiment of the present invention is the photocurable composition for nail or artificial nail according to any one of the first to third embodiments, comprising 0.1 to 50 parts by mass of the component (B) and 0.1 to 10 parts by mass of the component (C) relative to 100 parts by mass of the component (A).

[0014] A fifth embodiment of the present invention is the photocurable composition for nail or artificial nail according to any one of the first to fourth embodiments, wherein the component (A) comprises a (meth)acrylate oligomer and a (meth)acrylate monomer.

[0015] A sixth embodiment of the present invention is the photocurable composition for nail or artificial nail according to the fifth embodiment, wherein the (meth)acrylate monomer consists solely of monofunctional (meth)acrylate monomers and / or difunctional (meth)acrylate monomers.

[0016] A seventh embodiment of the present invention is the photocurable composition for nail or artificial nail according to the sixth embodiment, wherein the monofunctional (meth)acrylate monomer is a monofunctional (meth)acrylate monomer having a hydroxyl group.

[0017] An eighth embodiment of the present invention is the photocurable composition for nail or artificial nail according to the sixth or seventh embodiment, wherein the bifunctional (meth)acrylate monomer is dimethyloltricyclodecane di(meth)acrylate.

[0018] A ninth embodiment of the present invention is a photocurable composition for nails or artificial nails according to any one of the first to eighth embodiments, which is used for artistic gel nails.

[0019] Hereinafter, embodiments of the present invention will be described. However, the present invention is not limited to only the following embodiments. Furthermore, in this specification, unless otherwise specified, operations and measurements of physical properties are performed under conditions of room temperature (20°C or higher and 25°C or lower) and a relative humidity of 40% RH or higher and 50% RH or lower. Furthermore, in this specification, the photocurable composition for nails or artificial nails is also simply referred to as the "photocurable composition" or "composition."

[0020] One embodiment of the present invention is a photocurable composition for nails or artificial nails, comprising the following components (A) to (D): Component (A): a compound having a (meth)acryloyl group; Component (B): a polythiol compound; Component (C): a photoinitiator; Component (D): a filler comprising components (D-1) and (D-2); Component (D-1): a surface-treated fumed silica, the surface of which has a residue represented by the following formula 1:

[0021]

[0022] Here, n is an integer of 1 or more; Component (D-2): fumed silica that has been surface-treated, and whose surface residue is represented by the following formula 2.

[0023]

[0024] According to the present invention, a photocurable composition for nails or artificial nails containing a polythiol compound and fumed silica can achieve both a high structural viscosity ratio and high transparency (low turbidity) of the cured product. Therefore, the photocurable composition of the present invention is particularly suitable for art gel nails that form three-dimensional decorations.

[0025] The present invention will now be described in detail. The component (A) that can be used in the present invention may be any compound having a (meth)acryloyl group. Specifically, compounds such as (meth)acrylates and (meth)acrylamides can be used as the component (A). The component (A) also includes (meth)acrylate monomers and (meth)acrylate oligomers. In the present invention, acrylic and methacrylic are collectively referred to as (meth)acrylic. In this specification, the term "(meth)acrylic" encompasses both acrylic and methacrylic. Thus, for example, the term "(meth)acrylic acid" encompasses both acrylic acid and methacrylic acid. Similarly, the term "(meth)acryloyl" encompasses both acryloyl and methacryloyl. Thus, for example, the term "(meth)acryloyl group" encompasses both acryloyl and methacryloyl groups. The component (A) is preferably liquid at 25°C and can be suitably used if it has good compatibility with the components (B) and (C) of the present invention described below.

[0026] Component (A) preferably contains a (meth)acrylate monomer or a (meth)acrylate oligomer, and more preferably contains both a (meth)acrylate monomer and a (meth)acrylate oligomer. In a preferred embodiment of the present invention, component (A) consists of a (meth)acrylate monomer and a (meth)acrylate oligomer.

[0027] Specific examples of the (meth)acrylate oligomer include (meth)acrylate oligomers having an ester bond in the molecule, (meth)acrylate oligomers having an ether bond, (meth)acrylate oligomers having a urethane bond (urethane (meth)acrylate oligomer), and epoxy-modified (meth)acrylate oligomers, and the main skeleton thereof may be, but is not limited to, bisphenol A, novolac phenol, polybutadiene, polyester, polyether, etc. Two or more types of (meth)acrylate oligomers may be used in combination. The component (A) that can be used in the present invention also includes compounds having one or more epoxy groups and one or more (meth)acryloyl groups in one molecule.

[0028] For (meth)acrylate oligomers having an ester bond, a synthesis method is known in which an ester bond is formed by reacting a polyol with a polycarboxylic acid, and then (meth)acrylic acid is added to unreacted hydroxyl groups, but the synthesis method is not limited to this. Specific examples include Aronix M-6100, M-6200, M-6250, M-6500, M-7100, M-7300K, M-8030, M-8060, M-8100, M-8530, M-8560, and M-9050 manufactured by Toagosei Co., Ltd., and UV-3500BA, UV-3520TL, UV-3200B, and UV-3000B manufactured by The Nippon Synthetic Chemical Industry Co., Ltd., but are not limited thereto.

[0029] For (meth)acrylate oligomers having an ether bond, a synthesis method in which (meth)acrylic acid is added to the hydroxyl groups of a polyether polyol or to the hydroxyl groups of a polyether polyol having an aromatic group such as bisphenol is known, but the synthesis method is not limited to this. Specific examples include UV-6640B, UV-6100B, and UV-3700B manufactured by Nippon Synthetic Chemical Industry Co., Ltd., Light (meth)acrylate 3EG-A, 4EG-A, 9EG-A, 14EG-A, PTMGA-250, BP-4EA, BP-4PA, and BP-10EA manufactured by Kyoeisha Chemical Co., Ltd., and EBECRYL3700 manufactured by Daicel-Cytec Co., Ltd., but are not limited thereto.

[0030] Known synthetic methods for (meth)acrylate oligomers having a urethane bond include forming a urethane bond with a polyol and a polyisocyanate, and then adding a compound having a hydroxyl group and a (meth)acryloyl group in the molecule or (meth)acrylic acid to the remaining isocyanate group. From the viewpoint of improving durability, it is preferable to add a (meth)acrylate oligomer having a urethane bond. Specific examples include AH-600, AT-600, UA-306H, UF-8001G manufactured by Kyoeisha Chemical Co., Ltd., KY-11 manufactured by Negami Chemical Industrial Co., Ltd., and RUA-075 manufactured by Asia Industries Co., Ltd., but are not limited thereto.

[0031] Epoxy-modified (meth)acrylate oligomers can be synthesized by ring-opening polymerization of (meth)acrylic acid or the like with the glycidyl group of a polyfunctional glycidyl ether compound, but are not limited thereto. The main chain of the polyfunctional glycidyl ether can have a variety of skeletons, such as bisphenol A, bisphenol F, or novolac phenol. Specific examples of epoxy-modified (meth)acrylate oligomers include, but are not limited to, Epoxy Ester 3000A and 3002A manufactured by Kyoeisha Chemical Co., Ltd., and EBECRYL 3700 manufactured by Daicel-Allnex Corporation.

[0032] The weight-average molecular weight of the (meth)acrylate oligomer is not particularly limited, but is preferably 1,000 to 50,000, and more preferably 1,000 to 10,000. A weight-average molecular weight of 1,000 or more provides toughness to the cured product, while a weight-average molecular weight of 50,000 or less allows the composition to have a low viscosity. Here, the weight-average molecular weight refers to the weight-average molecular weight in terms of polystyrene measured by gel permeation chromatography. When two or more types of (meth)acrylate oligomers are used, it is preferable that the weight-average molecular weight of at least one type be within the above range, and it is more preferable that all weight-average molecular weights be within the above range. Furthermore, the (meth)acrylate oligomer preferably contains three or more (meth)acryloyl groups per molecule (trifunctional or higher). Furthermore, the (meth)acrylate oligomer is not particularly limited, but it is preferable that it contains five or fewer (meth)acryloyl groups per molecule (pentafunctional or lower).

[0033] The (meth)acrylate monomer may include monofunctional, difunctional, or trifunctional (meth)acrylate monomers and (meth)acrylamide monomers. Two or more types of (meth)acrylate monomers may be used in combination. A plurality of other (meth)acrylate monomers may also be used in combination. The molecular weight of these (meth)acrylate monomers is not particularly limited, but is, for example, less than 1,000.

[0034] In the photocurable composition of this embodiment, the component (A) preferably contains, as the (meth)acrylate monomer, a monofunctional (meth)acrylate monomer or a difunctional (meth)acrylate monomer, and more preferably contains both a monofunctional (meth)acrylate monomer and a difunctional (meth)acrylate monomer.

[0035] In a preferred embodiment of the present invention, the (meth)acrylate monomer consists solely of monofunctional (meth)acrylate monomers and / or difunctional (meth)acrylate monomers. In a preferred embodiment of the present invention, the (meth)acrylate monomer consists solely of monofunctional (meth)acrylate monomers and difunctional (meth)acrylate monomers. This makes it possible to obtain the effects of the present invention even more significantly.

[0036] Specific examples of monofunctional (meth)acrylate monomers include lauryl (meth)acrylate, stearyl (meth)acrylate, ethyl carbitol (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, caprolactone-modified tetrahydrofurfuryl (meth)acrylate, cyclohexyl (meth)acrylate, dicyclopentanyl (meth)acrylate, isobornyl (meth)acrylate, benzyl (meth)acrylate, phenyl (meth)acrylate, phenoxyethyl (meth)acrylate, phenoxydiethylene glycol (meth)acrylate, phenoxytetraethylene glycol (meth)acrylate, nonylphenoxyethyl (meth)acrylate, nonylphenoxytetraethylene glycol (meth)acrylate, methoxydiethylene glycol (meth)acrylate, ethoxydiethylene glycol (meth)acrylate, Examples of suitable acrylates include, but are not limited to, butoxyethyl (meth)acrylate, butoxytriethylene glycol (meth)acrylate, 2-ethylhexyl polyethylene glycol (meth)acrylate, 4-hydroxybutyl (meth)acrylate, nonylphenyl polypropylene glycol (meth)acrylate, methoxydipropylene glycol (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, glycerol (meth)acrylate, polyethylene glycol (meth)acrylate, polypropylene glycol (meth)acrylate, epichlorohydrin-modified butyl (meth)acrylate, epichlorohydrin-modified phenoxy (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, and N,N-diethylaminoethyl (meth)acrylate. It is preferable that component (A) contains a monofunctional (meth)acrylate monomer having a hydroxyl group. This can more significantly enhance the effects of the present invention. Specific examples of the monofunctional (meth)acrylate monomer having a hydroxyl group include, but are not limited to, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate.

[0037] In addition to the above, the monofunctional (meth)acrylate monomer also includes a (meth)acrylate monomer having an acidic group. Examples of the (meth)acrylate monomer having an acidic group include, in particular, a carboxylic acid or phosphoric acid having a (meth)acryloyl group in the molecule. Examples of carboxylic acids having a (meth)acryloyl group in the molecule include (meth)acrylic acid, 3-(meth)acryloyloxypropyl succinic acid, 4-(meth)acryloyloxybutyl succinic acid, 2-(meth)acryloyloxyethyl maleic acid, 3-(meth)acryloyloxypropyl maleic acid, 4-(meth)acryloyloxybutyl maleic acid, 2-(meth)acryloyloxyethyl hexahydrophthalic acid, 3-(meth)acryloyloxypropyl hexahydrophthalic acid, 4-(meth)acryloyloxybutyl hexahydrophthalic acid, 2-(meth)acryloyloxyethyl phthalic acid, 3-(meth)acryloyloxypropyl phthalic acid, and 4-(meth)acryloyloxybutyl phthalic acid. Examples of phosphoric acids having a (meth)acryloyl group in the molecule include, but are not limited to, 2-ethylhexyl acid phosphate, 2-hydroxyethyl methacrylate acid phosphate, dibutyl phosphate, etc. From the viewpoint of improving durability, it is preferable that component (A) contains a (meth)acrylate monomer having an acidic group.

[0038] Specific examples of bifunctional (meth)acrylate monomers include 1,3-butylene glycol di(meth)acrylate, 1,4-butylene glycol di(meth)acrylate, dimethyloltricyclodecane di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,6-hexane glycol di(meth)acrylate, ethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, and ethylene oxide-modified neopentyl glycol di(meth)acrylate. Examples of the bifunctional (meth)acrylate monomer include, but are not limited to, acrylate, propylene oxide-modified neopentyl glycol di(meth)acrylate, bisphenol A di(meth)acrylate, ethylene oxide-modified bisphenol A di(meth)acrylate, epichlorohydrin-modified bisphenol A di(meth)acrylate, ethylene oxide-modified bisphenol S di(meth)acrylate, neopentyl glycol-modified trimethylolpropane di(meth)acrylate, dicyclopentenyl di(meth)acrylate, ethylene oxide-modified dicyclopentenyl di(meth)acrylate, and di(meth)acryloyl isocyanurate. Among these, the bifunctional (meth)acrylate monomer is preferably dimethyloltricyclodecane di(meth)acrylate, and more preferably dimethyloltricyclodecane diacrylate. This allows the effects of the present invention to be more pronounced.

[0039] Specific examples of trifunctional (meth)acrylate monomers include trimethylolpropane tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, ethylene oxide (EO)-modified trimethylolpropane tri(meth)acrylate, propylene oxide (PO)-modified trimethylolpropane tri(meth)acrylate, epichlorohydrin (ECH)-modified trimethylolpropane tri(meth)acrylate, ECH-modified glycerol tri(meth)acrylate, tris(acryloyloxyethyl)isocyanurate, and caprolactone-modified tris(2-acryloyloxyethyl)isocyanurate, but are not limited to these.

[0040] Specific examples of (meth)acrylamide monomers include, but are not limited to, dimethyl(meth)acrylamide, (meth)acryloylmorpholine, and diethyl(meth)acrylamide. Although the exact cause is unknown, from the viewpoint of improving durability, it is preferable that the monomer contains a (meth)acrylamide monomer. In the present invention, specific examples of (meth)acrylamide monomers known include, but are not limited to, DMAA, ACMO, and DEAA manufactured by KJ Chemical Co., Ltd.

[0041] Examples of other (meth)acrylate monomers include tetra- or higher functional (meth)acrylate monomers such as dipentaerythritol hexa(meth)acrylate.

[0042] Component (A) preferably contains both a (meth)acrylate oligomer and a (meth)acrylate monomer. In this case, the ratio of the content of the (meth)acrylate oligomer to the (meth)acrylate monomer (mass ratio of (meth)acrylate oligomer:(meth)acrylate monomer) is preferably 50:50 to 95:5, more preferably 60:40 to 95:5, even more preferably 70:30 to 95:5, and preferably 70:30 to 80:20. When the photocurable composition contains two or more types of (meth)acrylate oligomers, the above content refers to the total amount of these. Similarly, when the photocurable composition contains two or more types of (meth)acrylate monomers, the above content refers to the total amount of these. The inclusion of a (meth)acrylate oligomer improves durability.

[0043] Furthermore, it is preferable to use a monofunctional (meth)acrylate monomer in combination with a difunctional or higher functional (meth)acrylate monomer as the (meth)acrylate monomer. When a monofunctional (meth)acrylate monomer and a difunctional or higher functional (meth)acrylate monomer are used in combination, the ratio of their contents (mass ratio of monofunctional (meth)acrylate monomer: difunctional or higher functional (meth)acrylate monomer) is not particularly limited, but is, for example, 95:5 to 5:95, preferably 80:20 to 50:50, and more preferably 70:30 to 60:40. Note that when the photocurable composition contains two or more monofunctional (meth)acrylate monomers, the above content refers to the total amount thereof. Similarly, when the photocurable composition contains two or more difunctional or higher functional (meth)acrylate monomers, the above content refers to the total amount thereof.

[0044] The component (B) that can be used in the present invention is a polythiol compound. The component (B) is not particularly limited as long as it is a compound having two or more thiol groups. Only one polythiol compound may be used, or two or more may be used in combination. Addition of the component (B) improves surface curability without oxygen inhibition. Specific examples of the component (B) include, but are not limited to, aliphatic polythiol compounds and aromatic polythiol compounds. The aliphatic polythiol compounds and aromatic polythiol compounds may be polythiol compounds having sulfide bonds and polythiol compounds having secondary thiol groups, respectively.

[0045] Examples of aliphatic polythiol compounds having two thiol groups include 1,2-ethanedithiol, 1,2-propanedithiol, 1,3-propanedithiol, 1,4-butanedithiol, 1,6-hexanedithiol, 1,7-heptanedithiol, 1,8-octanedithiol, 1,9-nonanedithiol, 1,10-decanedithiol, 1,12-dodecanedithiol, 2,2-dimethyl-1,3-propanedithiol, 3-methyl-1,5-pentanedithiol, 2-methyl-1,8-octanedithiol, and 1 ,4-cyclohexanedithiol, 1,4-bis(mercaptomethyl)cyclohexane, 1,1-cyclohexanedithiol, 1,2-cyclohexanedithiol, bicyclo[2,2,1]hepta-exo-cis-2,3-dithiol, 1,1-bis(mercaptomethyl)cyclohexane, bis(2-mercaptoethyl)ether, ethylene glycol bis(2-mercaptoacetate), and ethylene glycol bis(3-mercaptopropionate).

[0046] Aliphatic polythiol compounds having three thiol groups include, but are not limited to, 1,1,1-tris(mercaptomethyl)ethane, 2-ethyl-2-mercaptomethyl-1,3-propanedithiol, 1,2,3-propanetrithiol, trimethylolpropane tris(2-mercaptoacetate), trimethylolpropane tris(3-mercaptopropionate), and tris[(mercaptopropionyloxy)-ethyl]isocyanurate.

[0047] Examples of aliphatic polythiol compounds having four or more thiol groups include, but are not limited to, pentaerythritol tetrakis(2-mercaptoacetate), pentaerythritol tetrakis(3-mercaptopropionate), pentaerythritol tetrakis(3-mercaptobutyrate), and dipentaerythritol hexa-3-mercaptopropionate.

[0048] Examples of aromatic polythiol compounds 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(2-mercaptoethyl)benzene, 1,3-bis(2-mercaptoethyl)benzene, 1,4-bis(2-mercaptoethyl)benzene, 1,2-bis(2-mercaptoethyleneoxy)benzene, and 1,3-bis(2-mercaptoethyleneoxy)benzene. 1,4-bis(2-mercaptoethyleneoxy)benzene, 1,2,3-trimercaptobenzene, 1,2,4-trimercaptobenzene, 1,3,5-trimercaptobenzene, 1,2,3-tris(mercaptomethyl)benzene, 1,2,4-tris(mercaptomethyl)benzene, 1,3,5-tris(mercaptomethyl)benzene, 1,2,3-tris(2-mercaptoethyl)benzene, 1,2,4-tris(2-mercaptoethyl)benzene, 1,3,5-tris(2-mercaptoethyl)benzene, 1,2,3-tris(2-mercapto 1,2,4-Tris(2-mercaptoethyleneoxy)benzene, 1,3,5-Tris(2-mercaptoethyleneoxy)benzene, 1,2,3,4-tetramercaptobenzene, 1,2,3,5-tetramercaptobenzene, 1,2,4,5-tetramercaptobenzene, 1,2,3,4-tetrakis(mercaptomethyl)benzene, 1,2,3,5-tetrakis(mercaptomethyl)benzene, 1,2,4,5-tetrakis(mercaptomethyl)benzene, 1,2,3,4-tetrakis(2-mercaptoethyl)benzene benzene, 1,2,3,5-tetrakis(2-mercaptoethyl)benzene, 1,2,4,5-tetrakis(2-mercaptoethyl)benzene, 1,2,3,4-tetrakis(2-mercaptoethyleneoxy)benzene, 1,2,3,5-tetrakis(2-mercaptoethyleneoxy)benzene, 1,2,4,5-tetrakis(2-mercaptoethyleneoxy)benzene, 2,2'-mercaptobiphenyl, 4,4'-thiobis-benzenethiol, 4,4'-dimercaptobiphenyl, 4,4'-dimercaptobibenzyl, 2,5-toluenedithiol, 3,4-toluenedithiol, 1,4-naphthalenedithiol, 1,5-naphthalenedithiol, 2,6-naphthalenedithiol, 2,7-naphthalenedithiol, 2,4-dimethylbenzene-1,3-dithiol, 4,5-dimethylbenzene-1,3-dithiol, 9,10-anthracenedimethanethiol, 1,3-bis(2-mercaptoethylthio)benzene, 1,4-bis(2-mercaptoethylthio)benzene, 1,2-bis(2-mercaptoethylthiomethyl)benzene, 1,3-bis(2-mercaptoethylthiomethyl)benzene Examples of the mercaptoethylthio include, but are not limited to, benzene, 1,4-bis(2-mercaptoethylthiomethyl)benzene, 1,2,3-tris(2-mercaptoethylthio)benzene, 1,2,4-tris(2-mercaptoethylthio)benzene, 1,3,5-tris(2-mercaptoethylthio)benzene, 1,2,3,4-tetrakis(2-mercaptoethylthio)benzene, 1,2,3,5-tetrakis(2-mercaptoethylthio)benzene, and 1,2,4,5-tetrakis(2-mercaptoethylthio)benzene.

[0049] Examples of polythiol compounds having a sulfide bond include, but are not limited to, bis(2-mercaptoethyl)sulfide, bis(2-mercaptoethylthio)methane, 1,2-bis(2-mercaptoethylthio)ethane, 1,3-bis(2-mercaptoethylthio)propane, 1,2,3-tris(2-mercaptoethylthio)propane, tetrakis(2-mercaptoethylthiomethyl)methane, 1,2-bis(2-mercaptoethylthio)propanethiol, 2,5-dimercapto-1,4-dithiane, bis(2-mercaptoethyl)disulfide, 3,4-thiophenedithiol, 1,2-bis(2-mercaptoethyl)thio-3-mercaptopropane, and bis-(2-mercaptoethylthio-3-mercaptopropane)sulfide.

[0050] Specific examples of polythiol compounds having a secondary thiol group include, but are not limited to, pentaerythritol tetrakis(3-mercaptobutyrate), 1,4-bis(3-mercaptobutyryloxy)butane, 1,3,5-tris(3-mercaptobutyryloxyethyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, trimethylolpropane tris(3-mercaptobutyrate), trimethylolethane tris(3-mercaptobutyrate), trimethylolpropane tris(3-mercaptobutyrate), trimethylolethane tris(3-mercaptobutyrate), etc. Commercial products include, but are not limited to, PEMP manufactured by SC Organic Chemical Co., Ltd., and PE1, BD1, and NR1 of the Karenz MT (registered trademark) series manufactured by Showa Denko K.K.

[0051] The content of component (B) in the photocurable composition is not particularly limited, but is preferably 0.1 to 50 parts by mass, more preferably 1 to 30 parts by mass, even more preferably 1 to 10 parts by mass, and even more preferably 1 to 5 parts by mass, per 100 parts by mass of component (A). When component (B) is present in an amount of 0.1 part by mass or more, surface curability is improved, and when component (B) is present in an amount of 50 parts by mass or less, storage stability is improved. When the photocurable composition contains two or more polythiol compounds as component (B), the above content refers to the total amount of these compounds. Similarly, when component (A) contains two or more compounds having a (meth)acryloyl group, the above content refers to the total amount of these compounds.

[0052] The component (C) that can be used in the present invention is a photoinitiator. There are no limitations on the component (C) as long as it is a radical photoinitiator that generates radical species when exposed to energy rays such as visible light, ultraviolet light, X-rays, and electron beams.

[0053] Specific examples of the component (C) include non-visible light photoinitiators such as diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzyl dimethyl ketal, 4-(2-hydroxyethoxy)phenyl-(2-hydroxy-2-propyl)ketone, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-2-morpholino(4-thiomethylphenyl)propan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone, and 2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanone oligomer; benzoins such as benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and benzoin isobutyl ether; benzophenone, o-benzoyl methyl benzoate, and 4-hydroxybenzoyl methyl benzoate; benzophenones such as 1-phenylbenzophenone, 4-benzoyl-4'-methyl-diphenyl sulfide, 3,3',4,4'-tetra(t-butylperoxycarbonyl)benzophenone, 2,4,6-trimethylbenzophenone, 4-benzoyl-N,N-dimethyl-N-[2-(1-oxo-2-propenyloxy)ethyl]benzenemethanaminium bromide, and (4-benzoylbenzyl)trimethylammonium chloride; and thioxanthones such as 2-isopropylthioxanthone, 4-isopropylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone, 1-chloro-4-propoxythioxanthone, and 2-(3-dimethylamino-2-hydroxy)-3,4-dimethyl-9H-thioxanthone-9-one mesochloride, but are not limited thereto. Furthermore, multiple components (C) can also be used in combination.

[0054] Furthermore, component (C) preferably contains a visible light photoinitiator. The content of the visible light photoinitiator (when two or more types are used, the total content) relative to the total content of component (C) is, for example, 0 to 70% by mass, preferably more than 0 to 70% by mass, more preferably 10 to 60% by mass, and even more preferably 20 to 50% by mass. The inclusion of a visible light photoinitiator reduces yellowing of the cured product. Here, the visible light photoinitiator is a photoinitiator that has the strongest light absorption in the visible light region, and in particular, an acylphosphine oxide photopolymerization initiator containing a phosphorus atom is preferably used. Specific examples of visible light photoinitiators include, but are not limited to, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide and bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide.

[0055] The content of component (C) in the photocurable composition is not particularly limited, but is preferably 0.1 to 20 parts by mass, more preferably 0.1 to 10 parts by mass, and even more preferably 1 to 10 parts by mass, per 100 parts by mass of component (A). When the content of component (C) is 0.1 part by mass or more, photocurability can be maintained. On the other hand, when the content of component (C) is 20 parts by mass or less, storage stability can be maintained without increasing viscosity during storage. When the photocurable composition contains two or more photoinitiators as component (C), the above content refers to the total amount of these. Similarly, when the photocurable composition contains two or more compounds having a (meth)acryloyl group as component (A), the above content refers to the total amount of these.

[0056] The component (D) that can be used in the present invention is a filler containing components (D-1) and (D-2). Here, component (D-1) is surface-treated fumed silica, the surface residue of which is represented by the following formula 1, and component (D-2) is surface-treated fumed silica, the surface residue of which is represented by the following formula 2. Fumed silica is obtained by a dry process, specifically, silicon dioxide obtained by hydrolyzing silicon tetrachloride as a raw material in a flame of oxygen and hydrogen. However, these may aggregate in the photocurable composition. After production, fumed silica has exposed silanol (≡SiOH) groups. However, surface-treated fumed silica can be obtained by surface treatment (chemical modification) by reacting the surface of the fumed silica with a compound that reacts with silanol. The addition of component (D) can control viscosity and thixotropy. The component (D) preferably consists of only the components (D-1) and (D-2), and most preferably contains no fillers other than the components (D-1) and (D-2). For example, of all fillers contained in the photocurable composition, the total content of the components (D-1) and (D-2) is preferably 95% by mass or more, more preferably 99% by mass or more, and most preferably 100% by mass.

[0057] The surface-treated fumed silica of component (D-1) is fumed silica in which the surface has been chemically modified so that the residue on the surface has a structure represented by the following formula 1: where n is an integer of 1 or greater. n is, for example, an integer of 2 or greater. There is no particular upper limit for n, but it is, for example, 1000 or less, e.g., 100 or less. Component (D-1) can be, for example, fumed silica that has been surface-treated with polydimethylsiloxane.

[0058]

[0059] The surface-treated fumed silica of component (D-2) is fumed silica in which the surface has been chemically modified so that the residue on the surface has a structure represented by the following formula 2. Component (D-2) can be, for example, fumed silica that has been surface-treated with hexamethyldisilazane.

[0060]

[0061] The mass ratio of the (D-1) component to the (D-2) component ((D-1) component:(D-2) component) in the entire (D) component is not particularly limited, but is preferably 20:80 to 80:20, more preferably 30:70 to 70:30, and even more preferably 33:67 to 66:34. This allows for a higher level of both thixotropy and transparency of the cured product. When two or more (D-1) components are included, the content of the (D-1) component refers to the total amount. Similarly, when two or more (D-2) components are included, the content of the (D-2) component refers to the total amount. In particular, when the (D) component consists only of the (D-1) component and the (D-2) component, it is preferable that the mass ratio of the (D-1) component to the (D-2) component in the entire (D) component is within the above range. This allows for more pronounced effects of the present invention to be achieved.

[0062] The BET specific surface area of ​​component (D) is not particularly limited, but is preferably 10 to 500 m ２ / g, and 10 to 300m ２ / g, and more preferably 100 to 250m ２ / g is even more preferable. The particle size of component (D) is not particularly limited, but the average primary particle size of component (D) is, for example, 1 to 1,000 nm. Here, the average primary particle size is determined by observing the particle sizes of primary particles randomly sampled using an electron microscope and averaging the particle sizes. The average primary particle size of component (D) is preferably 1 to 50 nm. When fumed silica having an average primary particle size of 1 to 50 nm is contained in the composition, it is preferable that the fumed silica having an average primary particle size of 1 to 50 nm does not contain any fumed silica other than component (D) (component (D-1) and component (D-2)). Furthermore, the photocurable composition of this embodiment preferably does not contain any fumed silica other than component (D) (component (D-1) and component (D-2)).

[0063] Specific examples of the component (D-1) include, but are not limited to, the Aerosil (registered trademark) series manufactured by Nippon Aerosil Co., Ltd., such as RY50, RY51, NY50, NY50L, RY200S, R202, RY200, RY200L, and RY300, and TS-720 manufactured by CABOT Corp. The component (D-1) may be used alone or in combination of two or more types.

[0064] Specific examples of the component (D-2) include, but are not limited to, RX50, NAX50, NX90G, NX90S, NX130, RX200, R8200, RX300, R812, and R812S, which are part of the Aerosil (registered trademark) series manufactured by Nippon Aerosil Co., Ltd. The component (D-2) may be used alone or in combination of two or more types.

[0065] The content of component (D) in the photocurable composition is not particularly limited, but the content of component (D) is preferably 1.0 to 25 parts by mass, more preferably 1.0 to 10 parts by mass, per 100 parts by mass of component (A). Inclusion of 1.0 part by mass or more increases the structural viscosity ratio, while inclusion of 25 parts by mass or less reduces the turbidity (transparency) of the cured product. The content of component (D) is preferably 1.0 to 20.0% by mass, more preferably 1.0 to 10% by mass, of the entire composition. Furthermore, when component (D) consists solely of components (D-1) and (D-2), the content of component (D-1) is preferably 1.0 to 6.0 parts by mass, and the content of component (D-2) is preferably 0.1 to 6.0 parts by mass, per 100 parts by mass of component (A). When multiple types of component (D) are included, the above content refers to the total amount. Similarly, when multiple types of component (A) are contained, the above content refers to the total amount of these.

[0066] The photocurable composition of the present invention may contain additives such as coupling agents, inorganic fillers other than component (D), organic fillers, colorants such as pigments and dyes, antioxidants, polymerization inhibitors, antifoaming agents, leveling agents, rheology control agents, etc. in appropriate amounts within the range that does not impair the properties of the present invention. The addition of these additives can provide a composition or a cured product thereof that is excellent in photocurability, resin strength, adhesive strength, workability, storage stability, etc.

[0067] The photocurable composition of the present invention may contain a coupling agent within the range that does not impair the properties of the present invention. Examples of coupling agents include, but are not limited to, silane coupling agents having both an epoxy group, a vinyl group, an acryloyl group, or a methacryloyl group and a hydrolyzable silane group, polyorganosiloxanes having a phenyl group and a hydrolyzable silyl group, and / or polyorganosiloxanes having an epoxy group and a hydrolyzable silyl group. Specific examples of silane coupling agents include, but are not limited to, allyltrimethoxysilane, vinyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane, and 3-chloropropyltrimethoxysilane.

[0068] The photocurable composition of the present invention can be appropriately blended with fillers such as inorganic fillers and organic fillers other than component (D) as long as the properties of the present invention are not impaired. Blending a filler can adjust not only the viscosity and thixotropy but also the curability and toughness. Examples of inorganic fillers include, but are not limited to, alumina, silica, fumed silica other than component (D), metal powder, and glitter powder. Examples of organic fillers include, but are not limited to, styrene fillers, rubber fillers, and core-shell acrylic fillers. Specific examples of silica products include, but are not limited to, FUSELEX E-1 manufactured by Tatsumori Co., Ltd. and AO-802 manufactured by Adma Fine Co., Ltd.

[0069] The method for preparing the photocurable composition of the present invention is not particularly limited, and conventionally known methods can be appropriately employed. For example, predetermined amounts of components (A), (B), (D), and optional components are weighed and added to a stirring vessel sequentially or simultaneously in any order, and then mixed using a mixing means such as a planetary mixer, preferably while vacuum degassing. The production conditions are not particularly limited, but it is preferable to perform the process under light-shielded conditions. The mixing temperature is preferably 10 to 50°C, and the mixing time is preferably 0.1 to 5 hours. Subsequently, component (C) is weighed and added to the stirring vessel, and mixed using a mixing means such as a planetary mixer, preferably while vacuum degassing, to obtain a photocurable resin composition. The production conditions are not particularly limited, but it is preferable to perform the process under light-shielded conditions.

[0070] Although there are no particular limitations on the viscosity of the photocurable composition of the present invention, it is preferable that the viscosity at 25°C is 100 Pa·s or less, and more preferably 80 Pa·s or less. Within this range, handling during treatment can be improved. The viscosity of the photocurable composition is a value measured by the method described in the Examples below. The viscosity of the composition can be adjusted by appropriately selecting the type and content of the materials of the components (A) to (D).

[0071] The photocurable composition of the present invention is not particularly limited, but preferably has a structural viscosity ratio of 2.5 to 4.5. Within this range, coating properties can be improved. Furthermore, application can be appropriately controlled, facilitating three-dimensional decoration. The structural viscosity ratio of the photocurable composition is a value measured by the method described in the Examples below. The structural viscosity ratio of the composition can be adjusted by appropriately selecting the types and contents of the materials (A) to (D) above.

[0072] The photocurable composition of the present invention can be cured with energy rays such as visible light, ultraviolet light, X-rays, electron beams, etc. to give a cured product. The method for producing the cured product is not particularly limited.

[0073] For example, nail treatments can be performed on nails or artificial nails by applying the photocurable composition of the present invention to the nail or artificial nail and curing it. When performing nail treatments on human nails, it is preferable to sand the surface of the human nail with a file or the like before the treatment, and then remove dust, oil, moisture, etc. with a nail-specific solvent containing ethanol as the main component. Preferably, when applying the photocurable composition of the present invention to the nail or artificial nail, a coating film having a thickness of 100 to 300 μm before curing is formed using a brush or paintbrush. A primer may be used before application. The irradiation device used to cure the photocurable composition is not particularly limited, but commercially available UV lamps and LED lamps can be used. The wavelength of the irradiation light is, for example, 350 to 400 nm. The irradiation time is 15 to 120 seconds, and preferably 20 to 70 seconds considering the effect on the finger.

[0074] The turbidity of the cured product (cured product of the photocurable composition) obtained by curing the photocurable composition is not particularly limited, but is preferably 5.0 to 16.0%. This range is suitable for artistic gel nails. The turbidity of the cured product is measured by the method described in the Examples below. The turbidity of the cured product can be adjusted by appropriately selecting the type and content of the materials (A) to (D) above.

[0075] In compounds having a (meth)acryloyl group, polymerization is inhibited in areas exposed to oxygen due to oxygen inhibition. The photocurable composition of the present invention is less susceptible to oxygen inhibition due to the inclusion of a compound having a (meth)acryloyl group, and is rapidly curable upon light irradiation, making it suitable for nails and artificial nails. Oxygen inhibition can leave uncured components on the surface, causing stickiness and necessitating wiping. However, the photocurable composition of the present invention is less susceptible to oxygen inhibition, allowing for non-wiping, eliminating the need for wiping. Because the photocurable composition of the present invention has good surface curability, it is particularly suitable for art gel nails that form three-dimensional decorations.

[0076] The present invention will now be described in more detail with reference to examples, but the present invention is not limited to these examples.

[0077] The following components were prepared to prepare a photocurable composition for nails or artificial nails. (Hereinafter, the photocurable composition for nails or artificial nails will also be simply referred to as the photocurable composition or the composition.) Component (A): Compound having a (meth)acryloyl group - Polyether-based urethane acrylate oligomer having a weight average molecular weight of 5,000 and a functionality of 3 (KY-11, manufactured by Negami Chemical Industrial Co., Ltd.) - Urethane acrylate oligomer having a weight average molecular weight of 4,600 and a functionality of 5 (RUA-075, manufactured by Asia Kogyo Co., Ltd.) - 4-Hydroxybutyl acrylate (4-HBA, manufactured by Osaka Organic Chemical Industry Ltd.) - Dimethyloltricyclodecane diacrylate (Light Acrylate DCP-A, manufactured by Kyoeisha Chemical Co., Ltd.) - 2-Hydroxypropyl methacrylate (HPMA, manufactured by Nippon Shokubai Co., Ltd.) - Dipentaerythritol hexaacrylate (DPHA, manufactured by Daicel Allnex Corporation) Caprolactone-modified tris-(2-acryloyloxyethyl)isocyanurate (NK Ester A9300-1CL, manufactured by Shin-Nakamura Chemical Co., Ltd.) Component (B): Polythiol compound Trimethylolpropane tris(3-mercaptopropionate) (TMMP-20P, manufactured by SC Organic Chemical Co., Ltd.) Component (C): Photoinitiator 1-Hydroxycyclohexylphenyl ketone (invisible light photoinitiator) (Omnirad 184, manufactured by IGM Resins B.V.) 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (visible light photoinitiator) (Omnirad TPO H, manufactured by IGM Resins B.V.) Component (D): Filler consisting of components (D-1) and (D-2) Component (D-1): Surface-treated fumed silica, the surface residue of which is represented by the above formula 1. Fumed silica surface-treated with polydimethylsiloxane (BET specific surface area: 200 m ２ / g) (TS-720 manufactured by CABOT Corporation) Component (D-2): Surface-treated fumed silica, the surface residue of which is represented by the above formula 2. Fumed silica surface-treated with hexamethyldisilazane (BET specific surface area: 140 m ２ / g) (Aerosil (registered trademark) RX200, manufactured by Nippon Aerosil Co., Ltd.) Component (D'): fumed silica other than component (D) Untreated fumed silica (BET specific surface area: 200 m ２ / g) (Aerosil (registered trademark) 200, manufactured by Nippon Aerosil Co., Ltd.) Fumed silica surface-treated with octylsilane (BET specific surface area: 150 m ２ / g) (Aerosil (registered trademark) R805 manufactured by Nippon Aerosil Co., Ltd.) Fumed silica surface-treated with dimethyldichlorosilane (BET specific surface area: 110 m ２ / g) (Aerosil (registered trademark) R972 manufactured by Nippon Aerosil Co., Ltd.).

[0078] To 100 parts by mass of each raw material listed in Table 1, 10 parts by mass of component (D) (or component (D')) was added, and the mixture was stirred for 30 minutes while maintaining a reduced pressure using a planetary mixer to prepare a mixture. The structural viscosity ratio and turbidity of the mixture were measured as follows.

[0079] [Structural Viscosity Ratio of Mixture] The structural viscosity ratio was measured using a rheometer according to the following specifications. A HAAKE MARSIII manufactured by Thermo Fisher Scientific was used to measure the viscosity. The shear rate was 20 s －１ The viscosity at this time is viscosity 1, and the shear rate is 2s －１ The viscosity at this point was designated as viscosity 2. The value of viscosity 1 was designated as "viscosity (Pa s)," and the value of viscosity 2 / viscosity 1 was designated as the "structural viscosity ratio." In Table 1, when the mixture became dilatant rather than a viscoelastic body, the structural viscosity ratio was not measured, and the mixture was recorded as "dilatant." Furthermore, when component (D) (or component (D')) settled despite being stirred with a planetary mixer, the mixture was recorded as "separated."

[0080] [Turbidity of Mixture] A test piece was prepared by applying the composition to a thickness of 0.25 mm to an alkali-free glass plate having a length of 50 mm, a width of 50 mm, and a thickness of 0.7 mm, and the turbidity was measured using a haze meter NDH2000 manufactured by Nippon Denshoku Industries Co., Ltd. The result was recorded as "Turbidity (%)." In Table 1, in the case of "dilatancy" or "separation," no measurement was performed and the result was recorded as "not measured."

[0081]

[0082] In Table 1, in terms of the structural viscosity ratios of mixtures with component (A) or component (B), among the component (D) (or component (D')), component (D-1) TS-720 exhibited a high structural viscosity ratio (high thixotropy). Compared to (meth)acrylate oligomers and (meth)acrylate monomers, TS-720 exhibited a high structural viscosity ratio with the polythiol compound TMMP-20P, indicating that TS-720 exhibits a high structural viscosity ratio, particularly in compositions containing polythiol compounds. Furthermore, in terms of turbidity in Table 1, among the component (D) (or component (D')), component (D-2) RX200 exhibited low turbidity (high transparency). Compared to mixtures with (meth)acrylate oligomers and polythiol compounds, mixtures of RX200 with (meth)acrylate monomers tended to exhibit low turbidity. RX200 showed particularly low turbidity when mixed with 4-HBA, HPMA, and DPHA, which are (meth)acrylate monomers without a cyclic structure. This is thought to be because, when the (meth)acrylate monomer has a cyclic structure, the methyl groups on the surface of the RX200 particles and the cyclic structure of the (meth)acrylate monomer repel each other, which can lead to turbidity in the mixture. On the other hand, it was found that for 200, the (D') component, an appropriate structural viscosity ratio could not be measured depending on the raw materials mixed.

[0083] [Examples 1 to 5, Comparative Examples 1 to 3] [Preparation of Photocurable Composition] Component (A), component (B), and component (D) (or component (D')) were weighed into a stirring vessel and stirred for 30 minutes while degassing under vacuum. Finally, component (C) was weighed and added to the stirring vessel and stirred for 30 minutes to obtain a photocurable composition for each Example and Comparative Example. Detailed amounts prepared are shown in Table 2, with all values ​​expressed in parts by mass.

[0084]

[0085] The photocurable compositions of Examples 1 to 5 and Comparative Examples 1 to 3 were subjected to viscosity and structural viscosity ratio measurements, appearance confirmation, and turbidity measurements. The results are summarized in Table 3.

[0086] [Measurement of Viscosity and Structural Viscosity Ratio of Photocurable Composition] 0.5 ml of the composition was collected and dispensed into a measuring cup. Viscosity measurements were performed using an EHD viscometer (manufactured by Toki Sangyo Co., Ltd.) under the following conditions. The results are referred to as "viscosity (also referred to as viscosity at a rotational speed of 10 rpm) (Pa s)." Furthermore, "viscosity at a rotational speed of 1 rpm (Pa s)" was measured under the same measurement conditions as below, except that the rotational speed was 1 rpm. The viscosity at a rotational speed of 1 rpm / the viscosity at a rotational speed of 10 rpm was taken as the "structural viscosity ratio." The results are shown in Table 3 below. Considering handling during application and flowability, the viscosity (viscosity at a rotational speed of 10 rpm) is preferably 100 Pa s or less, and more preferably 80 Pa s or less. The structural viscosity ratio is preferably 2.5 to 4.5. Measurement conditions: Cone rotor: 3°×R14 Rotation speed: 10 rpm Measurement time: 3 minutes Measurement temperature: 25° C. (temperature controlled by a thermostatic bath).

[0087] [Appearance Check] A test piece was prepared by applying the composition to a thickness of 0.25 mm to an alkali-free glass plate measuring 50 mm long x 50 mm wide x 0.7 mm thick, and the composition was cured by irradiating it with light from a nail UV lamp (rated voltage: 100-110 V, 50-60 Hz, power consumption: 36 W, wavelength: 350-400 nm) for 60 seconds. The appearance was visually checked according to the following evaluation criteria, and the evaluation of "appearance" is shown in Table 3 below. ◯ indicates that the composition can be used without any problems: Evaluation criteria ◯: Colorless and transparent ×: Slightly cloudy white

[0088] [Turbidity Measurement] 1 mm thick SUS304 spacers were placed on both corners of an alkali-free glass plate measuring 50 mm long x 50 mm wide x 0.7 mm thick, and 1 g of the composition was applied to the glass plate. Next, the other glass plate was gently placed on top of the plate, taking care not to introduce air bubbles into the composition, to prepare a test piece. At this time, any excess composition flowed out, so the excess was wiped off. The prepared test piece was then placed in a nail UV lamp (rated voltage: AC 100 V 50-60 Hz, power consumption: 36 W, wavelength: 350-400 nm) and irradiated twice for 60 seconds to cure the composition. Note that n = 1 test piece was prepared. Next, the test piece containing the cured composition was measured using a haze meter NDH2000 manufactured by Nippon Denshoku Industries Co., Ltd., and the result was recorded as "turbidity (%)." Turbidity was measured three times and the average value was calculated. From the viewpoint of appearance, the "turbidity" is preferably 5.0 to 16.0%.

[0089]

[0090] In Comparative Example 1, only the component (D-1) was used, and in Comparative Example 2, only the component (D-2) was used. In Comparative Example 1, thixotropy was exhibited but the appearance and turbidity were poor, and in Comparative Example 2, the appearance was good but the thixotropy was low and the turbidity was inappropriate. In Comparative Example 3, the component (D'-2), which was a fumed silica that was surface-treated but whose surface residues were not of the structure represented by the above formula 2, was used. The turbidity was low and the appearance was good, but the structural viscosity ratio was not high. In Examples 1 to 5, the thixotropy was high, the turbidity was low, and the appearance was also rated "good," indicating that the product was transparent.

[0091] The present invention has a structural viscosity ratio that allows for appropriate control of application in nail treatments, while also achieving low turbidity and transparency. It is particularly suitable for art gel nails that create three-dimensional decorations.

[0092] This application is based on Japanese Patent Application No. 2021-184529, filed on November 12, 2021, the disclosure of which is incorporated by reference in its entirety.

Claims

1. A photocurable composition for nails or artificial nails containing the following components (A) to (D): Component (A): A compound having a (meth)acryloyl group Component (B): A polythiol compound Component (C): A photoinitiator Component (D): A filler containing component (D-1) and component (D-2) Component (D-1): Fumed silica that has been surface-treated, and the residue on the surface is fumed silica represented by the following formula 1:

2. The photocurable composition for nails or artificial nails according to claim 1, wherein the mass ratio of the component (D-1) to the component (D-2) in the whole component (D) is 20:80 to 80:20 ((D-1) component: (D-2) component).

3. The photocurable composition for nails or artificial nails according to claim 1, which contains 1.0 to 20.0% by mass of the component (D) with respect to the whole composition.

4. The photocurable composition for nails or artificial nails according to claim 1, which contains 0.1 to 50 parts by mass of the component (B) and 0.1 to 10 parts by mass of the component (C) with respect to 100 parts by mass of the component (A).

5. The photocurable composition for nails or artificial nails according to claim 1, wherein the component (A) contains a (meth)acrylate oligomer and a (meth)acrylate monomer.

6. The photocurable composition for nails or artificial nails according to claim 5, wherein the (meth)acrylate monomer consists only of a monofunctional (meth)acrylate monomer and / or a difunctional (meth)acrylate monomer.

7. The photocurable composition for nails or artificial nails according to claim 6, wherein the monofunctional (meth)acrylate monomer is a monofunctional (meth)acrylate monomer having a hydroxyl group.

8. The photocurable composition for nails or artificial nails according to claim 6, wherein the difunctional (meth)acrylate monomer is dimethyloltricyclodecane di(meth)acrylate.

9. The photocurable composition for nails or artificial nails according to claim 1, which is used for art gel nails.