Photocurable composition for nails or artificial nails

Abstract

To provide a photocurable composition for nails or artificial nails that develops gloss on the surface of the cured product, while ensuring the durability of the gloss.SOLUTION: A photocurable composition for nails or artificial nails comprises components (A)-(D). Relative to 100 pts.mass of the component (A), the component (B) is present in an amount of 30-70 pts.mass and the component (C) is present in an amount of 10-80 pts.mass. The component (A): a urethane-modified (meth)acrylate oligomer having a weight-average molecular weight of 3,000-6,000 and containing 3-5 (meth)acryloyl groups for each molecule. The component (B): a (meth)acrylate containing one or more (meth)acryloyl groups for each molecule, excluding the component (A). The component (C): a polythiol compound. The component (D): a photoinitiator.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a photocurable composition containing a thiol compound. [Background technology]

[0002] Patent Document 1 describes the invention of a so-called gel nail, and it is known that adding a polythiol compound to a compound having a (meth)acryloyl group improves photocurability, and accordingly improves surface curability, making it less susceptible to oxygen inhibition even at the interface exposed to oxygen. However, as a characteristic unique to gel nails, it is difficult to develop gloss on the surface of the cured product and make the gloss durable. In addition, nail treatment involves applying gel nails directly or indirectly to a person's natural nails and curing them by irradiating them with light, but the gel nails may self-heat during curing. In such cases, the heat causes stress and pain for the subjects.

[0003] On the other hand, gel nails containing polythiol tend to have poor storage stability due to their high photocurability, such as increased viscosity of the gel nail. In order to maintain storage stability, adding a polymerization inhibitor or the like can suppress radical polymerization and increase storage stability, but this also affects the gloss of the surface of the cured product. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2017-210475 A Summary of the Invention [Problem to be solved by the invention]

[0005] Conventionally, gel nails would self-heat, causing stress to the subject, and did not exhibit a gloss on the surface of the cured product. It was also difficult to achieve both storage stability and photocurability by adding a polythiol compound to a compound having a (meth)acryloyl group. [Means for solving the problem]

[0006] As a result of intensive research by the present inventors in order to achieve the above object, they have completed the present invention, which is a photocurable composition.

[0007] The gist of the present invention will now be described. A first embodiment of the present invention is a photocurable composition for nail or artificial nail, comprising components (A) to (D), in which 100 parts by mass of component (A) is 30 to 70 parts by mass of component (B) and 10 to 80 parts by mass of component (C). Component (A): A urethane-modified (meth)acrylate oligomer having a weight average molecular weight of 3,000 to 6,000 and containing 3 to 5 (meth)acryloyl groups per molecule. Component (B): (meth)acrylate having one or more (meth)acryloyl groups per molecule (excluding component (A)) Component (C): Polythiol compound Component (D): Photoinitiator

[0008] A second embodiment of the present invention is a photocurable composition for nail or artificial nail according to the first embodiment, wherein the component (A) has a polyether skeleton.

[0009] A third embodiment of the present invention is a photocurable composition for nail or artificial nail according to the first embodiment, in which the component (B) consists solely of a monofunctional (meth)acrylate and / or a difunctional (meth)acrylate.

[0010] A fourth embodiment of the present invention is the photocurable composition for nail or artificial nail according to the third embodiment, in which the monofunctional (meth)acrylate is a monofunctional (meth)acrylate having a hydroxyl group.

[0011] A fifth embodiment of the present invention is the photocurable composition for nail or artificial nail according to the third embodiment, wherein the bifunctional (meth)acrylate is dimethyloltricyclodecane diacrylate.

[0012] A sixth embodiment of the present invention is the photocurable composition for nail or artificial nail according to the first embodiment, further comprising a phosphorus-based compound as a storage stabilizer.

[0013] A seventh embodiment of the present invention relates to a method for producing a phosphorus-based compound, the phosphorus-based compound being a phosphonic acid compound R 1 ?P(=O)(OR 2 )2 (where R 1 , R 2 is independently hydrogen or an organic group.

[0014] An eighth embodiment of the present invention is a photocurable composition for nail or artificial nail for use as a top coat, comprising the photocurable composition for nail or artificial nail according to the first embodiment. Effect of the Invention

[0015] The present invention makes it possible to provide a photocurable composition that contains a compound having a (meth)acryloyl group and a polythiol compound, which suppresses self-heating during photocuring, exhibits gloss on the surface of the cured product, and has high storage stability without reducing curability. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] The present invention will be described in detail below. The component (A) that can be used in the present invention is a urethane-modified (meth)acrylate oligomer having a weight average molecular weight of 3000 to 6000 and containing 3 to 5 (meth)acryloyl groups per molecule. Hereinafter, acryloyl and methacryloyl will be collectively referred to as (meth)acryloyl, and a compound having a (meth)acryloyl group will also be referred to as (meth)acrylate.

[0017] The urethane-modified (meth)acrylate oligomer is a (meth)acrylate oligomer having a urethane bond, and a synthesis method is known in which a urethane bond is formed by polyol and polyisocyanate, and a compound having a hydroxyl group and a (meth)acryloyl group in the molecule or (meth)acryloyl acid is added to the remaining isocyanate group. From the viewpoint of improving durability and good photocurability, it is most preferable that the (A) component is a urethane-modified acrylate oligomer having a weight average molecular weight of 3000 to 6000 and containing 3 to 5 acryloyl groups per molecule.

[0018] Examples of polyols include polyol compounds having two or more hydroxyl groups in the molecule, specifically polyether polyols, polyester polyols, caprolactone diols, bisphenol polyols, polyisoprene polyols, hydrogenated polyisoprene polyols, polybutadiene polyols, hydrogenated polybutadiene polyols, castor oil polyols, polycarbonate diols, etc. Among them, polyether diols are preferred because they introduce a polyether skeleton from the viewpoint of expressing gloss. These may be used alone or in combination.

[0019] Polyisocyanates include compounds having two or more isocyanate groups in the molecule, and specific examples thereof include aromatic polyisocyanates and aliphatic polyisocyanates. Examples of aromatic polyisocyanates include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, tetramethylxylylene diisocyanate, diphenylmethane diisocyanate, naphthalene-1,5-diisocyanate, and triphenylmethane triisocyanate. Examples of alicyclic polyisocyanates include isophorone diisocyanate, bis(4-isocyanatocyclohexyl)methane, 1,3-bis(isocyanatomethyl)cyclohexane, 1,4-bis(isocyanatomethyl)cyclohexane, norbornane diisocyanate, and bicycloheptane triisocyanate. Examples of aliphatic polyisocyanates include hexamethylene diisocyanate, 1,3,6-hexamethylene triisocyanate, and 1,6,11-undeca triisocyanate. Among these, diisocyanates such as isophorone diisocyanate and hexamethylene diisocyanate are preferred.

[0020] Examples of compounds having a hydroxyl group and a (meth)acryloyl group include mono(meth)acrylates of dihydric alcohols such as ethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, and polyethylene glycol, and mono(meth)acrylates or di(meth)acrylates of trihydric alcohols such as trimethylolethane, trimethylolpropane, and glycerin. These may be used alone or in combination.

[0021] Component (A) contains 3 to 5 (meth)acryloyl groups per molecule and has a weight average molecular weight of 3000 to 6000, so that it does not generate heat during photocuring and can be cured quickly. Furthermore, the surface of the cured product does not remain tacky and develops a glossy finish.

[0022] A specific example is Art Resin KY-11 manufactured by Negami Chemical Industrial Co., Ltd., but is not limited to this.

[0023] The component (B) that can be used in the present invention is a (meth)acrylate having one or more (meth)acryloyl groups per molecule. However, the component (A) is excluded. The component (B) can be any compound having a (meth)acryloyl group. Specifically, it refers to a (meth)acrylate monomer or a (meth)acrylate oligomer. The difference between a monomer and an oligomer is that the weight average molecular weight (or molecular weight) can be divided by 1000, and the weight average molecular weight (or molecular weight) of a monomer is 1000 or less. The component (B) is preferably liquid in an atmosphere of 25°C, and can be used if it has good compatibility with the components (A) and (C) of the present invention.

[0024] Specific examples of the (meth)acrylate oligomer include urethane-modified (meth)acrylate oligomers other than component (A), (meth)acrylate oligomers having an ester bond in the molecule, (meth)acrylate oligomers having an ether bond, and epoxy-modified (meth)acrylate oligomers, and the main skeletons thereof include, but are not limited to, bisphenol A, novolac phenol, polybutadiene, polyester, polyether, etc. In addition, 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.

[0025] The urethane-modified (meth)acrylate oligomer other than component (A) is a urethane-modified (meth)acrylate oligomer having a weight average molecular weight of less than 3,000 or more than 6,000, or containing fewer than 3 or more than 5 (meth)acryloyl groups per molecule.

[0026] As for the (meth)acrylate oligomer having an ester bond, a synthesis in which a polyol and a polycarboxylic acid form an ester bond and acrylic acid is added to the unreacted hydroxyl group is known, 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, M-9050, etc. manufactured by Toa Gosei Co., Ltd., and UV-3500BA, UV-3520TL, UV-3200B, UV-3000B, etc. manufactured by Nippon Gosei Chemical Industry Co., Ltd., but are not limited thereto.

[0027] As for the (meth)acrylate oligomer having an ether bond, a synthesis method is known in which acrylic acid is added to the hydroxyl group of a polyether polyol or to the hydroxyl group of a polyether polyol having an aromatic group such as bisphenol, but this synthesis method is not limited thereto. 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.

[0028] The epoxy-modified (meth)acrylate oligomer can be synthesized by ring-opening polymerization of (meth)acrylic acid or the like to the glycidyl group of a multifunctional glycidyl ether compound, but is not limited thereto. The main chain of the multifunctional glycidyl ether can be one having various skeletons such as bisphenol A type, bisphenol F type, novolac phenol type, etc. Specific examples of the epoxy-modified acrylic oligomer include, but are not limited to, Epoxy Ester 3000A, 3002A, etc. manufactured by Kyoeisha Chemical Co., Ltd., and EBECRYL3700, etc. manufactured by Daicel-Allnex Corporation.

[0029] The (meth)acrylate monomer may include monofunctional, difunctional, and trifunctional (meth)acrylate monomers, and may be used alone or in combination of multiple monomers.

[0030] 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, butoxyethyl (meth)acrylate, butoxytriethylene glycol (meth)acrylate, Examples of the acrylate include, but are not limited to, ethylene 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. Preferably, the (A) component contains a monofunctional monomer having a hydroxyl group. Specifically, examples of the acrylate include, but are not limited to, 2-hydroxyethyl (meth)acrylate and 2-hydroxypropyl (meth)acrylate.

[0031] The monofunctional (meth)acrylate monomer also includes a (meth)acrylate monomer having an acidic group. In particular, it refers to a carboxylic acid or phosphoric acid having a (meth)acryloyl group in the molecule. Carboxylic acids having a (meth)acryloyl group in the molecule include (meth)acryloyl 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, and 3-(meth)acryloyloxypropyl hexahydrophthalic acid. Examples of phosphates having a (meth)acryloyl group in the molecule include, but are not limited to, 2-ethylhexyl acid phosphate, 2-hydroxyethyl methacrylate acid phosphate, and dibutyl phosphate. It is preferable to include a (meth)acrylate monomer having an acidic group in order to improve durability.

[0032] Specific examples of bifunctional (meth)acrylate monomers include 1,3-butylene glycol di(meth)acrylate, 1,4-butylene glycol di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,6-hexane glycol di(meth)acrylate, ethylene glycol diacrylate, tetraethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, dimethylol tricyclodecane di(meth)acrylate, and ethylene oxide modified neopentyl glycol di(meth)acrylate. Examples of the di(meth)acrylate include, but are not limited to, butyl glycol di(meth)acrylate, propylene oxide side 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, diacryloyl isocyanurate, etc. Considering the improvement of curing properties, it is preferable to include a bifunctional (meth)acrylate monomer having an alicyclic structure, and it is most preferable to use dimethyloltricyclodecane di(meth)acrylate. Here, the alicyclic structure refers to a cyclic aliphatic hydrocarbon structure, and specific examples thereof include cycloalkyls such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, butylhexyl, methylcyclohexyl, dimethylcyclohexyl, cycloheptyl, methylcycloheptyl, cyclooctyl, cyclononyl, and cyclodecyl, hydronaphthyl, 1-adamantyl, 2-adamantyl, norbornyl, methylnorbornyl, isobornyl, dicyclopentenyl, dicyclopentanyl, dicyclopentenyloxyethyl, and tricyclodecane.

[0033] Specific examples of trifunctional (meth)acrylate monomers include trimethylolpropane tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, EO-modified trimethylolpropane tri(meth)acrylate, PO-modified trimethylolpropane tri(meth)acrylate, ECH-modified trimethylolpropane tri(meth)acrylate, ECH-modified glycerol tri(meth)acrylate, tris(acryloyloxyethyl)isocyanurate, and the like, but are not limited to these.

[0034] From the viewpoint of developing surface curability and gloss, it is preferred that the monofunctional (meth)acrylate contains a monofunctional (meth)acrylate having a hydroxyl group, and the difunctional (meth)acrylate contains dimethyloltricyclodecanediacrylate.

[0035] Component (B) preferably contains a monofunctional (meth)acrylate and / or a bifunctional (meth)acrylate, more preferably contains only a monofunctional (meth)acrylate and / or a bifunctional (meth)acrylate, and most preferably contains only a monofunctional (meth)acrylate and a bifunctional (meth)acrylate. From the viewpoint of suppressing heat generation during treatment, component (B) preferably does not contain a trifunctional or higher functional (meth)acrylate.

[0036] The amount of component (B) is preferably 30 to 70 parts by mass, and most preferably 40 to 60 parts by mass, per 100 parts by mass of component (A). When component (B) is contained in an amount of 30 or more parts by mass, the viscosity of the composition is lowered to facilitate application, and when component (B) is contained in an amount of 70 or less parts by mass, the curability is good.

[0037] The (C) component that can be used in the present invention is a polythiol compound. The (C) component is not particularly limited as long as it has two or more thiol groups in one molecule, and one type may be used alone or two or more types may be used in combination. Specific examples of the (C) component that have a primary thiol group include aliphatic polythiol compounds, aromatic polythiol compounds, and polythiol compounds with sulfide bonds, but are not limited thereto.

[0038] 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).

[0039] Examples of 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.

[0040] 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.

[0041] 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, 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 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) Examples of the mercaptoethylthio benzene 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.

[0042] 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.

[0043] Commercially available examples of the component (C) having a primary thiol group include PEMP, TMMP, TMMP-20P, DPMP, and TEMPIC manufactured by SC Organic Chemical Co., Ltd., but are not limited to these.

[0044] Specific examples of the (C) component 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. Examples of 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.

[0045] The content of the (C) component is preferably 10 to 80 parts by mass, and more preferably 10 to 70 parts by mass, per 100 parts by mass of the (A) component. The content of 10 parts by mass or more of the (C) component improves surface curability, and the content of 80 parts by mass or less improves storage stability. The content of the (C) component is preferably more than 8% by mass and less than 30% by mass of the entire composition.

[0046] The component (D) that can be used in the present invention is a photoinitiator. There are no limitations on the component (D) 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.

[0047] Specific examples of the component (D) include acetophenones 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, 4-phenyl phenyl ketone, and the like. Benzophenone, 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, (4-benzoylbenzyl)trimethylammonium chloride, and other benzophenones; 2-isopropylthioxanthone, 4-isopropylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone, 1-chloro-4-propoxythioxanthone, 2-(3-dimethylamino-2-hydroxy)-3,4-dimethyl-9H-thioxanthone-9-one mesochloride, and other thioxanthones, but are not limited thereto. Also, multiple (D) components can be used in combination.

[0048] The amount of the (D) component is 0.1 to 20 parts by weight, more preferably 5 to 15 parts by weight, per 100 parts by weight of the (A) component. When the (D) component is more than 0.1 parts by weight, the photocurability can be maintained. On the other hand, when the (D) component is less than 20 parts by weight, the viscosity does not increase during storage and storage stability can be maintained. The visible light type photoinitiator is preferably contained at 0 to 70% by weight based on the total weight of the (D) component, and the cured product is less likely to yellow. Here, the visible light type photoinitiator is a photoinitiator with the strongest light absorption in the visible light region, and mainly refers to an acylphosphine oxide-based photopolymerization initiator containing a phosphorus atom. Specific examples include 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide and bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, but are not limited thereto.

[0049] The present invention may contain additives such as (meth)acrylamide monomers, storage stabilizers, coupling agents, inorganic or organic fillers, colorants such as pigments and dyes, antioxidants, polymerization inhibitors, defoamers, leveling agents, rheology control agents, etc. in appropriate amounts within the scope of the present invention. By adding these additives, a composition or a cured product thereof having excellent resin strength, workability, storage stability, etc. can be obtained.

[0050] In the present invention, (meth)acrylamide monomers can be added within a range that does not impair the characteristics of the present invention. Specific examples 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.

[0051] In the present invention, a storage stabilizer can be added within a range that does not impair the characteristics of the present invention. The storage stabilizer is a storage stabilizer having a pKa (acid dissociation constant) of 1.0 to 4.0, and does not include the (A) component and the (B) component. More specifically, it is an organic acid having a pKa of 1.0 to 4.0. Although the exact cause is unknown, adding it to the composition of the present invention improves both the storage stability such as viscosity and the surface curing property. pKa is one of the indicators that quantitatively expresses the strength of the acid (ease of dissociating hydrogen ions), and the lower the pKa, the stronger the acid is. It is known that pKa is measured by neutralization titration, absorptiometry, capillary electrophoresis, etc., and among them, neutralization titration is the most accurate. Particularly preferred as a storage stabilizer is a phosphorus compound as a storage stabilizer. Here, phosphonic acid and phosphoric acid are collectively called phosphorus compounds, excluding the (D) component. Most preferred is a phosphonic acid compound. The phosphonic acid compound is a compound having R 1 ?P(=O)(OR 2 )2, where R 1 is an organic group that is not bonded to a hydrogen or phosphorus atom through an oxygen atom, and R 2 are each independently hydrogen or an organic group. Examples of organic groups include, but are not limited to, phenyl groups and hydrocarbon groups. The most preferred component (D) is phenylphosphonic acid. The storage stabilizers may be used alone or in combination, but it is preferred that the composition does not contain any storage stabilizers other than the storage stabilizers mentioned above. Phosphoric acid is usually represented as P(=O)(OH)3, which is different from phosphonic acid, H?P(=O)(OH)2.

[0052] Specific examples of storage stabilizers include phosphoric acid (pKa=1.83), oxalic acid (pKa=1.04), and phosphonic acid compounds. In particular, phosphonic acid compounds include phenylphosphonic acid (pKa=1.83), vinylphosphonic acid (pKa=2.11), and methylphosphonic acid (pKa=2.38), but are not limited thereto. Storage stabilizers may be used alone or in combination. In addition, in order to avoid reducing storage stability in terms of viscosity, etc., it is preferable not to use organic acids with a pKa of more than 4.0 in addition to the storage stabilizers.

[0053] The storage stabilizer is preferably added in an amount of 0.01 to 5.0 parts by mass, and most preferably 0.01 to 2.0 parts by mass, per 100 parts by mass of component (A). When the storage stabilizer is 0.01 part by mass or more, viscosity change is suppressed, and when it is 5.0 parts by mass or less, surface curability is maintained. Furthermore, the storage stabilizer is preferably contained in an amount of 0.01 to 10.0% by mass with respect to the entire composition.

[0054] In the present invention, a coupling agent can be added within a range that does not impair the characteristics of the present invention. Examples of the coupling agent include, but are not limited to, silane-based 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 the silane-based coupling agent include, but are not limited to, allyltrimethoxysilane, vinyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane, and 3-chloropropyltrimethoxysilane.

[0055] In the present invention, fillers such as inorganic fillers and organic fillers can be appropriately added within a range that does not impair the characteristics of the present invention. By adding a filler, it is possible to adjust not only the viscosity and thixotropy but also the hardening property and toughness. Examples of inorganic fillers include, but are not limited to, alumina, silica, amorphous silica, etc. On the other hand, examples of organic fillers include, but are not limited to, styrene fillers, rubber fillers, and core-shell acrylic fillers. Specific products include silica such as FUSELEX E-1 manufactured by Tatsumori Co., Ltd. and AO-802 manufactured by Adma Fine Co., Ltd., and amorphous silica such as Aerosil series manufactured by Nippon Aerosil Japan Co., Ltd., including 200 (untreated), R972 (treated with dimethyldichlorosilane), R976 (treated with dimethyldichlorosilane), RY200 (treated with dimethylsilicone), RX200 (treated with hexamethyldisilazane), and R800 (treated with octylsilane), but are not limited to these.

[0056] When the photocurable composition for nails or artificial nails of the present invention is used as a so-called gel nail, the procedure is as follows. Before the procedure, the surface of the human nail is sanded with a file or the like, and then dust, oil, moisture, etc. are removed with a nail-specific solvent containing ethanol as the main component. When applying the present invention, a coating film having a thickness of 100 to 300 μm is formed in the pre-cured state with a brush or paintbrush. A primer may be used before applying. A commercially available LED lamp for gel nails is used as an irradiation device for curing. The irradiation time is 15 to 120 seconds, and preferably 20 to 70 seconds in consideration of the effect on the fingers.

[0057] The photocurable composition for nail or artificial nail of the present invention preferably has a viscosity at 25° C. of 10 Pa·s or less, more preferably 5 Pa·s or less, in consideration of the applicability during application.

[0058] It is known that when radical species are generated by energy rays to polymerize a compound having a (meth)acryloyl group, polymerization is suppressed in the area exposed to oxygen due to oxygen inhibition. In this case, uncured components remain on the surface of the cured product, so the uncured components are often wiped off with a rag or the like during application to give a glossy finish, and this tendency is particularly strong in top coats used on the outermost surface. However, the present invention is suitable for non-wipe top coats that are not susceptible to oxygen inhibition and are cured by light irradiation, so that no uncured components remain on the surface after curing. EXAMPLES

[0059] The present invention will now be described in more detail with reference to examples, but the present invention is not limited to these examples.

[0060] [Examples 1 to 6, Comparative Examples 1 to 4] The following components were prepared to prepare a photocurable composition. (Hereinafter, the photocurable composition for nails or artificial nails will also be simply referred to as the composition.) Component (A): A urethane-modified (meth)acrylate oligomer having a weight average molecular weight of 3,000 to 6,000 and containing 3 to 5 (meth)acryloyl groups per molecule. Weight average molecular weight: 5000, functional group number: 3 polyether-based urethane acrylate oligomer (Art Resin KY-11, manufactured by Negami Chemical Industries, Ltd.) Urethane-modified (meth)acrylate oligomer other than component (A) Weight average molecular weight: 38,000, polyether urethane acrylate with 2 functional groups (Shiko UV-3700B, Mitsubishi Chemical Corporation) Weight average molecular weight: 3500, polyether urethane acrylate with 2 functional groups (Art Resin UN-6303, manufactured by Negami Chemical Industries, Ltd.) Weight average molecular weight: 4900, urethane acrylate oligomer with 10 functional groups (Art Resin UN-904, manufactured by Negami Chemical Industries, Ltd.) Component (B): (meth)acrylate having one or more (meth)acryloyl groups per molecule (excluding component (A)) 2-Hydroxypropyl methacrylate (HPMA, manufactured by Nippon Shokubai Co., Ltd.) Dimethyloltricyclodecane diacrylate (Light Acrylate DCP-A, manufactured by Kyoeisha Chemical Co., Ltd.) Component (C): Polythiol compound Trimethylolpropane tris(3-mercaptopropionate) (TMMP-20P manufactured by SC Organic Chemical Co., Ltd.) Component (D): Photoinitiator 1-Hydroxycyclohexyl phenyl ketone (non-visible light photoinitiator) (IRGACURE184, manufactured by BASF) 2,4,6-Trimethylbenzoyl-diphenyl-phosphine oxide (visible light photoinitiator) (LUCIRIN TPO manufactured by BASF) Storage stabilizer Phenylphosphonic acid (reagent)

[0061] Examples 1 to 6 and Comparative Examples 1 to 4 are prepared. The composition is prepared by weighing component (A) (and other oligomers), component (B), component (C) and a storage stabilizer into a stirring vessel, and then stirring is performed for 30 minutes. Then, stirring is performed for 30 minutes while vacuum degassing. Finally, component (D) is weighed and added to the stirring vessel, and stirring is performed for 30 minutes. Detailed preparation amounts are shown in Table 1, and all values ​​are expressed in parts by mass.

[0062] [Table 1]

[0063] Storage stability, surface condition of the cured product, surface curability, glossiness, abrasion test, and heat generation during application were confirmed for Examples 1 to 6 and Comparative Examples 1 to 4. The results are summarized in Table 2.

[0064] [Storage stability confirmation] 100 g of the composition is placed in a glass container and left in a hot air drying oven at 60°C for 3 days. The composition is then removed after 3 days and the properties of the composition are visually inspected according to the following evaluation criteria to determine "storage stability". Evaluation criteria ○: When the container is tilted, there is fluidity ×: No fluidity when container is tilted (gelation)

[0065] [Check the surface condition of the cured product] The composition is applied with a brush to a thickness of 300 μm on an acrylic plate of 2.0 mm thickness x 25 mm width x 100 mm length. The composition is cured by irradiating with a nail UV lamp (rated voltage: 100-110 V 50-60 Hz power consumption: 36 W, wavelength: 350-400 nm) for 30 seconds. The surface gloss is determined by visual inspection using the LED stand to reflect the light according to the following evaluation criteria. Evaluation criteria ○: The surface is glossy ×: The surface has no gloss.

[0066] [Surface hardening confirmation] The composition is applied with a brush to a thickness of 300 μm on an acrylic plate of 2.0 mm thick x 25 mm wide x 100 mm long. The composition is cured by irradiating with a nail UV lamp (rated voltage: 100-110 V, 50-60 Hz, power consumption: 36 W, wavelength: 350-400 nm) for 30 seconds. The surface condition of the cured product is visually confirmed by touching the surface with a cotton swab according to the following evaluation criteria, and is regarded as "surface curability". Evaluation criteria ○: No tackiness of ingredients on the surface ×: The ingredients become sticky on the surface.

[0067] [Gloss measurement] A test piece was prepared by electrochemically coating one side of a clear amino alkyd paint on the substrate SPCC-SD, coating the composition on the electrochemically coated surface to a thickness of 100 μm, and curing the composition by irradiating it with a nail UV lamp (rated voltage: 100-110 V 50-60 Hz power consumption: 36 W, wavelength: 350-400 nm) for 30 seconds to prepare a test piece. The "initial gloss (%)" of the surface of the test piece was measured using a high gloss gloss checker manufactured by Horiba Ltd. at an incident angle of 60° and a receiving angle of 60°. For the appearance to have a glossy appearance, the initial gloss should be 85% or more.

[0068] [Wear test] The surface of the test piece measured in the above gloss measurement is wiped with a rag 100 times, and the same measurement as the gloss measurement is performed again to obtain the "glossiness (%) after abrasion." The "glossiness change rate (%)" is calculated by "glossiness change rate (%)" = ("glossiness (%) after abrasion" - "initial glossiness (%)") / "initial glossiness (%)" x 100. From the viewpoint of durability, the glossiness after abrasion is preferably 85% or more. The glossiness change rate is preferably -6.0 to 0.0%, and most preferably -3.0 to 0.0%.

[0069] [Check for fever during treatment] After sanding the nails, dust and oil are removed with a nail solvent (mainly ethanol). The composition is applied as a base coat wet to a thickness of approximately 100 μm. The composition is applied with a brush. The composition is then cured by irradiating it with a nail LED lamp (rated voltage: 100-110 V 50-60 Hz, power consumption: 36 W, wavelength: 350-400 nm) for 30 seconds. In the same manner, the color coat and top coat are cured in sequence on the surface of the base coat under the same conditions. The color coat was Super Color EX (color: pastel peach) manufactured by PREGEL, and the top coat was each composition. The fingernails (10 fingers) of one person's hand were evaluated for "heat generation during treatment" according to the following evaluation criteria. Considering the stress of the subject, it is preferable to be "○". Evaluation criteria ○: No heat felt △: Slightly warm ×: Hot

[0070] [Table 2]

[0071] Comparing Examples 1 to 6 with Comparative Examples 1 and 2, it can be seen that the surface curing property is improved by including 10 to 80 parts by mass of the (C) component per 100 parts by mass of the (A) component. In addition, Examples 1 to 6 use a urethane-modified (meth)acrylate oligomer having a weight average molecular weight of 3000 to 6000 and containing 3 to 5 (meth)acryloyl groups per molecule as the (A) component, and heat generation during treatment is suppressed compared to Comparative Examples 3 and 4, which use other urethane-modified (meth)acrylate oligomers. Furthermore, in Examples 1 to 6, there is a tendency for the gloss change rate after wear to be lower compared to Comparative Example 2. [Industrial Applicability]

[0072] The present invention is a photocurable composition that contains polythiol but has both surface curability and storage stability. In particular, in the nail field, viscosity changes affect application, so the present invention allows stable application. In addition, the present invention does not generate heat during application, but has good surface curability, so it can be used as a non-wipe top coat.

Claims

1. A photocurable composition for nails or artificial nails comprising components (A) to (D), in which the composition contains 30 to 70 parts by mass of component (B) and 10 to 80 parts by mass of component (C) relative to 100 parts by mass of component (A). Component (A): a urethane-modified (meth)acrylate oligomer having a weight average molecular weight of 3,000 to 6,000 and containing 3 to 5 (meth)acryloyl groups per molecule. Component (B): (meth)acrylate having one or more (meth)acryloyl groups per molecule (excluding component (A)) Component (C): Polythiol compound Component (D): Photoinitiator

2. The photocurable composition for nails or artificial nails according to claim 1 , wherein the component (A) has a polyether skeleton.

3. 2. The photocurable composition for nails or artificial nails according to claim 1, wherein the component (B) consists essentially of a monofunctional (meth)acrylate and / or a difunctional (meth)acrylate.

4. The photocurable composition for nail or artificial nail according to claim 3 , wherein the monofunctional (meth)acrylate is a monofunctional (meth)acrylate having a hydroxyl group.

5. 4. The photocurable composition for nails or artificial nails according to claim 3, wherein the bifunctional (meth)acrylate is dimethyloltricyclodecane diacrylate.

6. 2. The photocurable composition for nail or artificial nail according to claim 1, further comprising a phosphorus-based compound as a storage stabilizer.

7. The phosphorus compound is a phosphonic acid compound R １ ?P(=O)(OR ２ ) ２ (where R １ , R ２ The photocurable composition for nails or artificial nails according to claim 6, wherein each of the groups independently represents hydrogen or an organic group.

8. A photocurable composition for nails or artificial nails for use as a top coat, comprising the photocurable composition for nails or artificial nails according to claim 1 .

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