Curable artificial nail composition

Abstract

To provide a curable artificial nail composition, even when containing a polyfunctional (meth)acrylate compound, having a sufficiently high crosslink density of a cured coating film, usable as a fill-in gel on nails for a long period of time without any problem, and further having a suppressed temperature rise during curing.SOLUTION: A curable artificial nail composition includes (a) one or more urethane (meth)acrylate oligomers having a weight-average molecular weight of 5,000 or more, (b) one or more urethane (meth)acrylate oligomers having a weight-average molecular weight of 1,000 or more and less than 5,000, (c) one or more alicyclic monofunctional methacrylate compounds, (d) one or more (meth)acrylamide compounds, and (e) a polymerization initiator, where the content of (c) the alicyclic monofunctional methacrylate compound is 5.0 mass% or more and 25.0 mass% or less based on 100 mass% of the total amount of the curable artificial nail composition.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a curable artificial nail composition. [Background technology]

[0002] Nail art, which involves decorating natural fingernails or toenails or gluing artificial nails onto them, is becoming increasingly popular. Artificial nails are also being formed on top of natural nails to reinforce them and prevent them from cracking or peeling due to external forces. For such nail decoration or reinforcement, resin-containing materials known as manicures, pedicures, and sculptures are applied to the nails.

[0003] As a material used for decorating or reinforcing nails, a photocurable artificial nail composition known as gel nails has been attracting attention. Gel nails are photocurable gel-type nail coating materials (photocurable artificial nail compositions), and are known to contain, for example, a (meth)acrylate oligomer and a (meth)acrylic monomer. Gel nails are applied to nails and cured by irradiating them with ultraviolet light, forming a crosslinked polymer coating through a radical polymerization reaction, which is believed to form a tough coating that is resistant to peeling from the nail. Patent Documents 1 to 6 disclose photocurable gel nail coating materials (photocurable artificial nail compositions) called gel nails, which contain, for example, a (meth)acrylate compound. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-55771 [Patent Document 2] Japanese Patent Publication No. 2022-167213 [Patent Document 3] Japanese Patent Application Laid-Open No. 2013-43853 [Patent Document 4] Japanese Patent Application Publication No. 2019-85394 [Patent Document 5] Japanese Patent Publication No. 2020-152793 [Patent Document 6] Japanese Patent Application Laid-Open No. 2017-105759 Summary of the Invention [Problem to be solved by the invention]

[0005] Recently, gel nails have been replaced with new ones using the fill-in method. This method involves leaving the base gel behind and sanding off the top layer of the base gel with a sanding machine, without removing the entire gel nail. Then, a new gel nail is applied on top of that, creating a new gel nail. Regular base gels wear off after about three to four weeks. However, fill-in gels must be highly durable, maintaining their quality on the nails for approximately three to four months, until the nails are fully grown. For this reason, fill-in gels are often designed with a higher crosslink density in the cured film than regular gels that wear off. A low crosslink density makes them more susceptible to moisture, allowing moisture from the inside (the nail side) and external sources such as household water to accumulate in the cured film, potentially resulting in a deterioration in durability. Furthermore, a low crosslink density of the cured film can be difficult to withstand external impacts, causing plastic deformation of the cured film and potentially leading to problems such as lifting and chipping.

[0006] To increase the crosslink density of a cured coating film, a method of incorporating a multifunctional (meth)acrylate compound is generally used. However, this method poses the problem of increasing the temperature during curing. However, the inventors have confirmed that even when a multifunctional compound is incorporated, the curing heat does not reach the expected range. This means that the multifunctional compound is relatively unreacted, indicating that the crosslink density of the cured coating film is not sufficiently improved. As a result, there is a problem in that the quality of the coating cannot be maintained on the nail without problems for approximately 3 to 4 months until the nail is fully grown, and there is a high possibility of defects occurring.

[0007] The problem to be solved by the present invention is to provide a curable artificial nail composition that has high durability, excellent curability, and a suppressed temperature rise during curing. [Means for solving the problem]

[0008] As a result of extensive research into solving the above problems, the present inventors have found that the above problems can be solved by a curable artificial nail composition having a specific composition, and have thus completed the present invention. Specifically, the following applies: [Section 1] (a) one or more urethane (meth)acrylate oligomers having a weight average molecular weight of 5,000 or more; (b) one or more urethane (meth)acrylate oligomers having a weight average molecular weight of 1,000 or more and less than 5,000; (c) one or more alicyclic monofunctional methacrylate compounds; (d) one or more (meth)acrylamide compounds; (e) a polymerization initiator, Contains the content of the (c) alicyclic monofunctional methacrylate compound is 5.0% by mass or more and 25.0% by mass or less, based on 100% by mass of the total amount of the curable artificial nail composition; Curable artificial nail composition. [Section 2] Item 2. The curable artificial nail composition according to Item 1, wherein the urethane (meth)acrylate oligomer (a) and / or the urethane (meth)acrylate oligomer (b) contains a polyether-based urethane (meth)acrylate oligomer and / or a polycarbonate-based urethane (meth)acrylate oligomer. [Section 3] Item 3. The curable artificial nail composition according to Item 1 or 2, further comprising (f) one or more trifunctional or higher functional (meth)acrylate compounds. [Section 4] Item 4. The curable artificial nail composition according to any one of Items 1 to 3, wherein the (d) (meth)acrylamide compound contains dimethylacrylamide and / or hydroxyethylacrylamide. [Effects of the Invention]

[0009] The present invention provides a curable artificial nail composition that has high durability, excellent curability, and a suppressed temperature rise during curing. The curable artificial nail composition of the present invention can be used on nails as a fill-in gel for a long period of time without any problems. The mechanism by which the curable artificial nail composition of the present invention exerts such effects is unknown, but the present inventors speculate as follows.

[0010] The curable artificial nail composition of the present invention contains (a) one or more urethane (meth)acrylate oligomers having a weight-average molecular weight of 5,000 or more, (b) one or more urethane (meth)acrylate oligomers having a weight-average molecular weight of 1,000 or more but less than 5,000, (c) one or more alicyclic monofunctional methacrylate compounds, and (d) one or more (meth)acrylamide compounds. This controls the balance of factors related to "reaction rate, curing heat" and "crosslink density," and is presumed to result in sufficient reactivity without excessively high curing heat, resulting in a cured coating film with an appropriately high hardness. In controlling the reaction rate and curing heat, it is thought that the curing heat can be reduced by using one or more (c) alicyclic monofunctional methacrylate compounds, which are monomers with high homopolymer Tg and low molecular mobility, and that the reactivity can be increased by using one or more (d) (meth)acrylamide compounds, which have low Q values ​​in the Qe theory and high radical stability, and that the reactivity can be further increased by using one or more (b) urethane (meth)acrylate oligomers with a weight average molecular weight of 1,000 or more and less than 5,000, which have a large number of vinyl groups per unit molecular weight. When controlling the crosslink density (improving the crosslink density) to increase the hardness of the cured coating film, it is presumed that the crosslink density can be increased by using one or more urethane (meth)acrylate oligomers (b) with a large number of vinyl groups per unit molecular weight and a weight-average molecular weight of 1,000 or more but less than 5,000, and furthermore, if necessary, by using one or more (f) trifunctional or higher (meth)acrylate compounds. However, the present invention is not limited to these speculations. DETAILED DESCRIPTION OF THE INVENTION

[0011] The curable artificial nail composition of the present invention will be described below. In this specification, "urethane (meth)acrylate oligomer" refers to "urethane acrylate oligomer" and "urethane methacrylate oligomer", "(meth)acrylamide" refers to "acrylamide" and "methacrylamide", and "(meth)acrylate" refers to "acrylate" and "methacrylate".

[0012] [(a) Urethane (meth)acrylate oligomer having a weight-average molecular weight of 5,000 or more] The (a) urethane (meth)acrylate oligomer having a weight-average molecular weight of 5,000 or more contained in the curable artificial nail composition of the present invention is not particularly limited as long as it is an oligomer having one or more (meth)acryloyloxy groups (CH═CHCOO— groups and / or CH═C(CH)COO— groups) in the molecule, having a urethane bond in the main skeleton, and having a plurality of repeating units, and has a weight-average molecular weight of 5,000 or more. (a) The urethane (meth)acrylate oligomer having a weight-average molecular weight of 5,000 or more has the effect of optimizing the viscosity of the curable artificial nail composition and adjusting the curability. Furthermore, it has the effect of optimizing the curing heat generated during curing of the curable artificial nail composition, as well as the release properties, hardness, and elongation of the cured coating film of the curable artificial nail composition.

[0013] The weight-average molecular weight is 5,000 or more, for example, 6,000 or more, preferably 10,000 or more, and more preferably 12,000 or more, and can be, for example, 100,000 or less, preferably 50,000 or less, and more preferably 35,000 or less. By setting the weight-average molecular weight within this range, it is possible to improve the durability of the cured coating film while maintaining low viscosity.

[0014] The number of (meth)acryloyl groups contained in one molecule is not particularly limited, but is 1 to 10, preferably 2 to 8, from the viewpoints of the curability of the curable artificial nail composition and the hardness of the cured coating film. The number of (meth)acryloyl groups can be confirmed by analysis using infrared absorption spectroscopy (IR), nuclear magnetic resonance (NMR), gas chromatography mass spectrometry (GC / MS), or the like.

[0015] A urethane (meth)acrylate oligomer having a weight-average molecular weight of 5,000 or more can be synthesized, for example, by reacting a polyol with a polyisocyanate to form an isocyanate group- or hydroxyl group-containing urethane prepolymer, and then reacting the isocyanate group- or hydroxyl group-containing urethane prepolymer with a compound having an active hydrogen-containing group and a (meth)acryloyl group in the molecule (hydroxyalkyl (meth)acrylate, (meth)acrylic acid, etc.) or a compound having an isocyanate group and a (meth)acryloyl group in the molecule, but the synthesis method is not limited to this. The urethane (meth)acrylate oligomer having a weight average molecular weight of 5,000 or more can be selected from those having one or more skeletons selected from the group consisting of a polyether skeleton, a polycarbonate skeleton, a polyester skeleton, an acrylic skeleton, and a polyolefin skeleton.

[0016] The urethane (meth)acrylate oligomer having a weight average molecular weight of 5,000 or more may be either a commercially available product or a synthetic product. KSM SUA TH1, SUA-TH2, KN20-32, etc. Mitsubishi Chemical's Shiko series (UV-6640B, UV-3300B, UV-3700B, UV-3310B, UV-3500BA, UV3200B, UV-3000B, UV-3520EA, UV-7610B, etc.); Negami Industrial Art Resin series (UN-6200, UN-6207, UN-6304, UN-6305, UN-6306, UN-6307, UN-6060S, PMH-101B, PMH-401B, MB-191, UN-9000PEP, UN-9200A, UN-353, UN-350, UN-7600, UN-7700, MBU-71, UN-952, UN-905, H-575, etc.); Daicel-Allnex EBECRYL series (230, 4491, 8411, 3700, etc.); Daicel Allnex KRM series (9465, 9556, 8961, etc.); Examples of suitable compounds include, but are not limited to, one or more selected from the group consisting of:

[0017] In the present invention, the urethane (meth)acrylate oligomer having a weight average molecular weight of 5,000 or more is preferably at least one of a polyether-based urethane (meth)acrylate oligomer having a polyether skeleton and / or a polycarbonate-based urethane (meth)acrylate oligomer having a polycarbonate skeleton.

[0018] The polyether-based polyurethane (meth)acrylate oligomer is not particularly limited as long as it is an oligomer having one or more (meth)acryloyl groups in the molecule and having a plurality of polyether repeating units and polyurethane repeating units. The polycarbonate-based polyurethane (meth)acrylate oligomer is not particularly limited as long as it has one or more (meth)acryloyl groups in the molecule and has a plurality of polycarbonate repeating units and a plurality of polyurethane repeating units.

[0019] Polyether-based polyurethane (meth)acrylate oligomers can be synthesized, for example, by reacting a polyisocyanate component with a polyol component containing a polyether-based polyol to form an isocyanate group- or hydroxyl group-containing urethane prepolymer, and then reacting the isocyanate group- or hydroxyl group-containing urethane prepolymer with a compound having an active hydrogen-containing group and a (meth)acryloyl group in the molecule (hydroxyalkyl (meth)acrylate, (meth)acrylic acid, etc.) or a compound having an isocyanate group and a (meth)acryloyl group in the molecule, but are not limited to this method. In the present invention, preferred are those obtained by reacting a polyisocyanate component with a polyol component to form an isocyanate group-containing urethane prepolymer, and then reacting the isocyanate group-containing urethane prepolymer with a hydroxyl group-containing (meth)acrylate compound.

[0020] Polycarbonate-based polyurethane (meth)acrylate oligomers can be synthesized, for example, by reacting a polyisocyanate component with a polyol component containing a polycarbonate-based polyol to form an isocyanate group- or hydroxyl group-containing urethane prepolymer, and then reacting the isocyanate group- or hydroxyl group-containing urethane prepolymer with a compound having an active hydrogen-containing group and a (meth)acryloyl group in the molecule (hydroxyalkyl (meth)acrylate, (meth)acrylic acid, etc.) or a compound having an isocyanate group and a (meth)acryloyl group in the molecule, but are not limited to this method. In the present invention, preferred are those obtained by reacting a polyisocyanate component with a polyol component to form an isocyanate group-containing urethane prepolymer, and then reacting the isocyanate group-containing urethane prepolymer with a hydroxyl group-containing (meth)acrylate compound.

[0021] Examples of the polyisocyanate component used in producing the polyether-based polyurethane (meth)acrylate oligomer and the polycarbonate-based polyurethane (meth)acrylate oligomer include one or more selected from the group consisting of tolylene diisocyanate, diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate, phenylene diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, naphthalene diisocyanate, hexamethylene diisocyanate, 1,5-pentamethylene diisocyanate, isophorone diisocyanate, methylenebis(4-cyclohexyl isocyanate), trimethylhexamethylene diisocyanate, hydrogenated tolylene diisocyanate, dicyclohexylmethane diisocyanate, carbodiimide-modified polyisocyanates of these, and isocyanurate-modified polyisocyanates of these.

[0022] Examples of the polyether-based polyol used in producing the polyether-based polyurethane (meth)acrylate oligomer include one or more selected from the group consisting of polyalkylene polyols such as polyoxyethylene polyol, polyoxypropylene polyol, polyoxybutylene polyol, and poly(oxyethylene-oxypropylene) polyol. The polycarbonate polyol used in producing the polycarbonate-based polyurethane (meth)acrylate oligomer may be one or more compounds having a hydroxyl group at the end of the polycarbonate molecular chain.

[0023] Examples of polyol components other than polyether-based polyols and polycarbonate-based polyols that can be used in producing polyether-based polyurethane (meth)acrylate oligomers and polycarbonate-based polyurethane (meth)acrylate oligomers include one or more selected from the group consisting of ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, co(polyethylene oxide-propylene oxide)diol, tetramethylene glycol, polytetramethylene glycol, bisphenol A, ethoxylated bisphenol A, caprolactone-modified polyols, carbonate polyols, polyester polyols, 1,6-hexanediol, trimethylolpropane, glycerin, pentaerythritol, dipentaerythritol, and the like.

[0024] Examples of the (meth)acrylate compound having a hydroxyl group used in producing the polyether-based polyurethane (meth)acrylate oligomer and the polycarbonate-based polyurethane (meth)acrylate oligomer include one or more compounds selected from the group consisting of 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, polyethylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, tris(hydroxyethyl)isocyanuric acid di(meth)acrylate, pentaerythritol tri(meth)acrylate, and the like.

[0025] Examples of polyether-based polyurethane (meth)acrylate oligomers include those obtained by adding a (meth)acrylic compound having a hydroxyl group such as hydroxyethyl (meth)acrylate to an isocyanate group-containing polyether urethane prepolymer obtained by reacting a polyoxyalkylene polyol such as polyoxypropylene polyol with a polyisocyanate such as isophorone diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, or an isocyanurate or biuret product of these, and then subjecting the (meth)acrylic compound having a hydroxyl group to an addition reaction of 10% or more of the total number of isocyanate groups in the urethane prepolymer.

[0026] Examples of polycarbonate-based polyurethane (meth)acrylate oligomers include those obtained by adding a (meth)acrylic compound having a hydroxyl group such as hydroxyethyl (meth)acrylate to an isocyanate group-containing polyether urethane prepolymer obtained by reacting a polycarbonate polyol with a polyisocyanate such as isophorone diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, or an isocyanurate or biuret product of any of these, and then subjecting the (meth)acrylic compound having a hydroxyl group to an addition reaction of 10% or more of the total number of isocyanate groups in the urethane prepolymer.

[0027] The content of (a) urethane (meth)acrylate oligomer having a weight-average molecular weight of 5,000 or more in the curable artificial nail composition of the present invention is not particularly limited. Taking the total amount of the curable artificial nail composition as 100% by mass, the content can be, for example, 20% by mass or more, preferably 30% by mass or more, and more preferably 35% by mass or more, and can be, for example, 70% by mass or less, preferably 60% by mass or less, and more preferably 55% by mass or less. If the content is less than 20% by mass, the viscosity may be too low, resulting in poor application properties, and the cured coating film may become too hard and brittle. If the content exceeds 70% by mass, the viscosity may be too high, resulting in poor application properties.

[0028] [(b) Urethane (meth)acrylate oligomer having a weight-average molecular weight of 1,000 or more but less than 5,000] The urethane (meth)acrylate oligomer (b) having a weight-average molecular weight of 1,000 or more and less than 5,000 contained in the curable artificial nail composition of the present invention is not particularly limited as long as it is an oligomer having one or more (meth)acryloyloxy groups (CH═CHCOO— groups and / or CH═C(CH)COO— groups) in the molecule, having a urethane bond in the main skeleton, and having a plurality of repeating units, and has a weight-average molecular weight of 1,000 or more and less than 5,000. (b) The urethane (meth)acrylate oligomer having a weight-average molecular weight of 1,000 or more but less than 5,000 optimizes the viscosity of the curable artificial nail composition and adjusts its curability. It also optimizes the heat generated during curing of the curable artificial nail composition, as well as the release properties, hardness, and elongation of the cured coating film of the curable artificial nail composition.

[0029] The weight average molecular weight is 1,000 or more and less than 5,000, for example, 1,200 or more, preferably 1,500 or more, and for example, 4,500 or less, preferably 4,000 or less.

[0030] The number of (meth)acryloyl groups contained in one molecule is not particularly limited, but is 1 to 10, preferably 2 to 8, from the viewpoints of the curability of the curable artificial nail composition and the hardness of the cured coating film. The number of (meth)acryloyl groups can be confirmed by analysis using infrared absorption spectroscopy (IR), nuclear magnetic resonance (NMR), gas chromatography mass spectrometry (GC / MS), or the like.

[0031] A urethane (meth)acrylate oligomer having a weight-average molecular weight of 1,000 or more but less than 5,000 can be synthesized, for example, by reacting a polyol with a polyisocyanate to form an isocyanate group- or hydroxyl group-containing urethane prepolymer, and then reacting the isocyanate group- or hydroxyl group-containing urethane prepolymer with a compound having an active hydrogen-containing group and a (meth)acryloyl group in the molecule (hydroxyalkyl (meth)acrylate, (meth)acrylic acid, etc.) or a compound having an isocyanate group and a (meth)acryloyl group in the molecule, but the synthesis method is not limited to this.

[0032] The urethane (meth)acrylate oligomer having a weight average molecular weight of 1,000 or more and less than 5,000 may be either a commercially available product or a synthetic product. SUA-16N manufactured by KSM Co., Ltd., etc.; Mitsubishi Chemical's Shiko series (UV-1700B, UV-6300B, UV-6630B, UV-7620B, UV-7630, UV-7640B, UV-7650B, etc.); Negami Industrial Co., Ltd. Art Resin series (UN-6303PR, STQI-037PR, UN-5500, UN-5590, UN-333, UN-3320HA, UN-3320HC, UN-904, UN-901T, UN-954, UN-2310, UN-2601, UN-2701, SMT-001, etc.); Daicel-Allnex EBECRYL series (210, 220, 270, 4220, 4666, 4680, 4820, 8402, 8701, etc.); Daicel Allnex KRM series (2000, 7735, 8904, 8452, 8528, 8296, etc.); Examples of suitable compounds include, but are not limited to, one or more selected from the group consisting of:

[0033] The content of (b) urethane (meth)acrylate oligomer having a weight-average molecular weight of 1,000 or more but less than 5,000 in the curable artificial nail composition of the present invention is not particularly limited. Taking the total amount of the curable artificial nail composition as 100% by mass, the content can be, for example, 5% by mass or more, preferably 10% by mass or more, and more preferably 15% by mass or more, and can be, for example, 40% by mass or less, preferably 30% by mass or less, and more preferably 25% by mass or less. If the content is less than 5% by mass, the viscosity may be too low, resulting in poor application properties, and the cured coating film may become too hard and brittle. If the content exceeds 40% by mass, the viscosity may be too high, resulting in poor application properties.

[0034] [(c) Alicyclic monofunctional methacrylate compound] The (c) alicyclic monofunctional methacrylate compound contained in the curable artificial nail composition of the present invention is not particularly limited as long as it is a compound having one methacryloyloxy group (CH═C(CH)COO— group) and an alicyclic group in the molecule. The (c) alicyclic monofunctional methacrylate compound imparts the effect of improving the curability while suppressing an excessive reaction rate of the curable artificial nail composition. Furthermore, it imparts the effect of optimizing the curing heat during curing of the curable artificial nail composition, and the release properties, hardness, and elongation of the cured coating film of the curable artificial nail composition.

[0035] (c) Examples of the alicyclic monofunctional methacrylate compound include one or more selected from the group consisting of cycloalkyl methacrylates in which the cycloalkyl group has 3 to 10 carbon atoms, such as cyclopropyl methacrylate, cyclobutyl methacrylate, cyclopentyl methacrylate, cyclohexyl methacrylate, cycloheptyl methacrylate, cyclooctyl methacrylate, cyclononyl methacrylate, and cyclodecyl methacrylate; isobornyl methacrylate, norbornyl methacrylate, adamantyl methacrylate, dicyclopentanyl methacrylate, dicyclopentenyloxyethyl methacrylate, dicyclopentadiene methacrylate, dicyclopentenyl methacrylate, tricyclodecanyl methacrylate, and tricyclodecanyloxyethyl methacrylate. Among these, one or more selected from the group consisting of isobornyl methacrylate, norbornyl methacrylate, and cyclohexyl methacrylate are preferred, with isobornyl methacrylate being more preferred.

[0036] The content of the (c) alicyclic monofunctional methacrylate compound is 5.0% by mass or more and 25.0% by mass or less, preferably 7% by mass or more, more preferably 10% by mass or more, and preferably 23% by mass or less, more preferably 20% by mass or less, based on 100% by mass of the total amount of the curable artificial nail composition. If the (c) alicyclic monofunctional methacrylate compound exceeds 25% by mass, the viscosity of the curable artificial nail composition may become too low, resulting in poor application properties, and the reactivity of the curable artificial nail composition may decrease, resulting in poor strength of the cured coating film. If the content is less than 5% by mass, the viscosity of the curable artificial nail composition may become too high, resulting in poor application properties, making it difficult to reduce the heat generated during curing, and resulting in poor coating film strength.

[0037] [(d) (Meth)acrylamide compounds] The (d) (meth)acrylamide compound contained in the curable artificial nail composition of the present invention is not particularly limited as long as it is a compound having one or more (meth)acrylamide groups (CH═CHCON< group and / or CH═C(CH)CONH< group) in the molecule. (d) The (meth)acrylamide compound improves the reaction rate of the curable artificial nail composition and improves the adhesive strength of the cured coating film.

[0038] (d) Examples of the (meth)acrylamide compound include (meth)acrylamide, diacetone (meth)acrylamide, N-methyl (meth)acrylamide, N-ethyl (meth)acrylamide, N-methylol (meth)acrylamide, N-methoxymethyl (meth)acrylamide, N-butoxymethyl (meth)acrylamide, N-isopropyl (meth)acrylamide, Nn-butoxymethyl (meth)acrylamide, N-isobutoxymethyl (meth)acrylamide, Nt-butyl (meth)acrylamide, N-acryloylmorpholine, N-(2-hydroxyethyl) (meth)acrylamide, N-(hydroxymethyl) (meth)acrylamide, N-[3-(dimethylamino)propyl] (meth)acrylamide, N-(1,1-dimethyl-3-oxobutyl) (meth)acrylamide, 2-(meth)acrylamido-2-methylpropanesulfonic acid, Nt-butyl (meth)acrylamide, N-methyl ... and at least one selected from the group consisting of t)acrylamidosulfonic acid, N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N,N-dipropyl(meth)acrylamide, N,N-diisopropyl(meth)acrylamide, N,N-dibutyl(meth)acrylamide, N,N-diisobutyl(meth)acrylamide, N,N-di-t-butyl(meth)acrylamide, N,N-diheptyl(meth)acrylamide, N,N-dioctyl(meth)acrylamide, N,N-di-t-octyl(meth)acrylamide, N,N-didodecyl(meth)acrylamide, N,N-dioctadecyl(meth)acrylamide, N,N-dimethylaminopropyl(meth)acrylamide, N,N-dimethylaminoethyl(meth)acrylamide, N,N-dimethylaminopropyl(meth)acrylamide, and N,N'-methylenebis(meth)acrylamide. Of these, N,N-dimethylacrylamide and / or N-hydroxyethylacrylamide are preferred.

[0039] The content of the (d) (meth)acrylamide compound is not particularly limited. It can be, for example, 20% by mass or less, preferably 15% by mass or less, and more preferably 10% by mass or less, relative to the total amount (100% by mass) of the curable artificial nail composition. It can be, for example, 1% by mass or more, preferably 2% by mass or more, and more preferably 5% by mass or more. If the (d) (meth)acrylamide compound exceeds 20% by mass, the curing heat generated during curing of the curable artificial nail composition may become too high, the water resistance and alcohol resistance of the cured coating film may decrease, making it more prone to peeling, and there may be a problem with a particular odor. If the content is less than 1% by mass, the reaction rate of the curable artificial nail composition may not be improved, and curing may take a long time and / or may result in poor curing.

[0040] [(e) Polymerization initiator] The polymerization initiator (e) contained in the curable artificial nail composition of the present invention is not particularly limited as long as it generates radicals when given energy by irradiation with light (e.g., ultraviolet light) or heat, and is capable of initiating polymerization of components (a) to (d). Examples of the polymerization initiator include one or more polymerization initiators selected from the group consisting of acylphosphine oxides, α-hydroxyalkylphenones, benzoin ethers, benzil ketals, acid esters, α-aminoalkylphenones, benzophenones, thioxanthones, titanocenes, quinones, peroxides, azo compounds, and persulfates. For example, the photopolymerization initiator has the effect of imparting good curability to the curable artificial nail composition even when irradiated with light using various light sources including a UV-LED light source.

[0041] For example, acylphosphine oxide polymerization initiators generate radicals when irradiated with ultraviolet light having a wavelength of 365 to 405 nm, which is emitted from commonly used UV-LED light sources. Therefore, even when curing is performed by irradiating light using various light sources, including UV-LED light sources, the curable composition can be imparted with good curability. Furthermore, when curing is performed by irradiating light using a UV-LED light source, yellowing of the cured coating film can be prevented. Examples of acylphosphine oxide polymerization initiators include one or more selected from the group consisting of 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, and 2,4,6-trimethylbenzoylethoxyphenylphosphine oxide. In the present invention, 2,4,6-trimethylbenzoyldiphenylphosphine oxide (OMNIRAD TPO) and 2,4,6-trimethylbenzoylethoxyphenylphosphine oxide are preferably used. 2,4,6-trimethylbenzoyldiphenylphosphine oxide is preferably used because it also functions as a skin conditioning agent.

[0042] Examples of polymerization initiators other than acylphosphine oxide polymerization initiators include 1-hydroxycyclohexylphenyl ketone (OMNIRAD 184), 1-(4-(phenylthio)-2,2-(O-benzoyloxime))1-hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one, 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methylpropan-1-one, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methylpropionyl)-benzyl]-phenyl}-2-methyl Propan-1-one, 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propan-1-one, thioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-isopropylthioxanthone, 2-chlorothioxanthone, 1-chloro-4-propylthioxanthone, 3-[3,4-dimethyl-9-oxo-9H-thioxanthone-2-yl-oxy]-2-hydroxypropyl-N,N,N-trimethylammonium chloro lide, fluorothioxanthone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one, 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one, oligo(2-hydroxy-2-methyl-1-(4-(1-methylvinyl)phenyl)propanone), 4-benzoyl-4'-methyl-diphenyl sulfide, 1,2-octanedione, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, 2-benzyl-2 -Dimethylamino-1-(4-morpholinophenyl)-butanone-1,2,2-dimethoxy-1,2-diphenylethan-1-one, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methylpropionyl)-benzyl]phenyl}-2-methylpropane, isophthalphenone, methyl phenylglyoxylate, butylanthraquinone, ethylanthraquinone, phenanthrenequinone, camphorquinone, benzophenone, 4-phenylbenzophenone, benzoylbenzoic acid, hydroxybenzophenone, 4,4'-Bis(diethylamino)benzophenone, benzoin, benzoin ethyl ether, benzoin isopropyl ether, benzoin butyl ether, benzoin isobutyl ether, benzil dimethyl ketal, 4-phenoxydichloroacetophenone, 4-t-butyl-dichloroacetophenone, 4-t-butyl-trichloroacetophenone, diethoxyacetophenone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone, 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2' -Azobis(2-amidinopropane) dihydrochloride, 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(isobutyronitrile), 2,2'-azobis-2-methylbutyronitrile, 1,1-azobis(1-cyclohexanecarbonitrile), 2,2'-azobis(2-methylpropionitrile), 2,2'-azobis(2-cyclopropylpropionitrile), 2,2'-azobis(methyl isobutyrate), t-butyl hydroperoxide, cumene hydroperoxide, diacetyl peroxide, didecanoyl peroxide , di-t-butyl peroxide, methyl ethyl ketone peroxide, cyclohexanone peroxide, dicumyl peroxide, di(3,5,5-trimethylhexanoyl) peroxide, 2,5-dimethylhexane-2,5-dihydroperoxide, dilauroyl peroxide, disuccinic acid peroxide, dibenzoyl peroxide, parachlorobenzoyl peroxide, 2,4-dichlorobenzoyl peroxide, t-butyl peroxypivalate, t-butyl peroxybenzoate, t-hexyl peroxide Sidevalerate, 2,5-dimethyl-2,5-di(2-ethylhexanoylperoxy)hexane, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, t-hexylperoxy-2-ethylhexanoate, t-butylperoxy-2-ethylhexanoate, n-butyl-4,4-di(t-butylperoxy)valerate, 1,1-di(t-butylperoxy)cyclohexane, 1,1-di(t-hexylperoxy)cyclohexane, 2,2-bis(4,4-di-t-butylperoxycyclohexyl)propane, 1,Examples of the peroxycarbonate include one or more selected from the group consisting of 1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane, 2,2-bis(t-butylperoxy)butane, 2,2-bis(t-butylperoxy)octane, dicetyl peroxydicarbonate, t-hexylperoxyisopropyl monocarbonate, diisopropyl peroxydicarbonate, t-butylperoxyisopropyl carbonate, di(4-t-butylcyclohexyl)peroxydicarbonate, di(2-ethylhexyl)peroxydicarbonate, potassium persulfate, sodium persulfate, and ammonium persulfate.

[0043] In the curable artificial nail composition of the present invention, it is preferable to use a polymerization initiator that can generate radicals and initiate polymerization when irradiated with ultraviolet light having wavelengths of around 405 nm and around 365 nm during curing, and it is more preferable to use a polymerization initiator containing an acylphosphine oxide polymerization initiator. In addition to the acylphosphine oxide polymerization initiator, a polymerization initiator containing an α-hydroxyalkylphenone polymerization initiator may also be used, or a polymerization initiator composition containing an acylphosphine oxide polymerization initiator and a peroxide polymerization initiator may also be used.

[0044] The content of the (e) polymerization initiator is not particularly limited. It is, for example, 0.1% by mass or more, preferably 1.0% by mass or more, more preferably 4.0% by mass or more, and for example, 15.0% by mass or less, preferably 12.0% by mass or less, more preferably 10.0% by mass or less, based on 100% by mass of the total amount of the curable artificial nail composition. If the content of the (e) polymerization initiator exceeds 15.0% by mass, the cured coating film of the curable artificial nail composition may become brittle or may yellow. If the content of the (e) polymerization initiator is less than 0.1% by mass, the curing of the curable artificial nail composition may take a long time or may not cure properly.

[0045] The (e) polymerization initiator may be a polymerization initiator containing an acylphosphine oxide polymerization initiator and an α-hydroxyalkylphenone polymerization initiator. In this case, the content of the acylphosphine oxide polymerization initiator is, relative to 100% by mass of the total curable artificial nail composition, for example, 0.05% by mass or more, preferably 0.5% by mass or more, more preferably 1.0% by mass or more, and for example, 4.0% by mass or less, preferably 3.0% by mass or less, and more preferably 2.0% by mass or less. The content of the α-hydroxyalkylphenone polymerization initiator is, relative to 100% by mass of the total curable artificial nail composition, for example, 1.0% by mass or more, preferably 2.0% by mass or more, more preferably 3.0% by mass or more, and for example, less than 15.0% by mass, preferably 12.0% by mass or less, and more preferably 10.0% by mass or less. The total content of the acylphosphine oxide polymerization initiator and the α-hydroxyalkylphenone polymerization initiator is, for example, 1.05% by mass or more, preferably 2.0% by mass or more, more preferably 3.0% by mass or more, even more preferably 4.0% by mass or more, and even more preferably 4.1% by mass or more, and is, for example, 15.0% by mass or less, preferably 12.0% by mass or less, and more preferably 10.0% by mass or less. If the content of the acylphosphine oxide polymerization initiator exceeds 4.0% by mass, the cured coating film of the curable artificial nail composition may become brittle or yellow. If the content of the acylphosphine oxide polymerization initiator is less than 0.05% by mass, the curing heat of the curable artificial nail composition may be high, and the temperature rise during curing may be large.

[0046] [(f) Trifunctional or higher (meth)acrylate compounds] The (f) tri- or higher functional (meth)acrylate compound that may be contained in the curable artificial nail composition of the present invention is not particularly limited as long as it is a compound having three or more (meth)acrylate compounds in the molecule and is a compound other than (a) and (b). (f) The tri- or higher functional (meth)acrylate compound improves the crosslink density of the cured coating film of the curable artificial nail composition, and imparts the effect of improving the durability of the cured coating film.

[0047] (f) The tri- or higher functional (meth)acrylate compound may be one or more selected from the group consisting of tri- or higher functional (meth)acrylate monomers and tri- or higher functional acrylate oligomers other than urethane (meth)acrylate oligomers. Among these, tri- or higher functional (meth)acrylate monomers are preferred. (f) The tri- or higher functional (meth)acrylate compound preferably has a molecular weight (weight average molecular weight) of less than 1,000.

[0048] Examples of trifunctional or higher functional (meth)acrylate monomers include trimethylolpropane tri(meth)acrylate (trimethylolpropane triacrylate alone, trimethylolpropane trimethacrylate alone, or a mixture of trimethylolpropane triacrylate and trimethylolpropane trimethacrylate); polypentaerythritol octa(meth)acrylate (polypentaerythritol octa(meth)acrylate, an ester of a hydroxyl group of a pentaerythritol polymer having eight (meth)acrylate groups with (meth)acrylic acid (for example, "tripentaerythritol acrylate, a mixture of mono- and dipentaerythritol acrylate, and polypentaerythritol acrylate" (manufactured by Osaka Organic Chemical Industry, Ltd., "Viscoat #802, TriPEA"); glycerin tri(meth)acrylate, ditrimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, ε-caprolactone-modified tris( tri(meth)acrylate monomers such as acryloxyethyl isocyanurate; tetra(meth)acrylate monomers such as pentaerythritol tetra(meth)acrylate and dipentaerythritol tetra(meth)acrylate; polypentaerythritol monomers such as dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, tripentaerythritol hexa(meth)acrylate and tetrapentaerythritol hexa(meth)acrylate; and (meth)acrylate monomers having four or more (meth)acrylate groups, such as ethanol poly(meth)acrylate, isocyanuric acid tri(meth)acrylate, triazine tri(meth)acrylate, ethoxylated isocyanuric acid triacrylate, and ethoxylated pentaerythritol tetraacrylate. Among these, trimethylolpropane tri(meth)acrylate is preferred, and trimethylolpropane trimethacrylate is more preferred.

[0049] The content of the (f) trifunctional or higher (meth)acrylate compound is not particularly limited and can be, for example, 20% by mass or less, preferably 15% by mass or less, and more preferably 10% by mass or less, relative to 100% by mass of the total amount of the curable artificial nail composition, and can be, for example, 1% by mass or more, preferably 2% by mass or more, and more preferably 5% by mass or more. (f) When the content of a trifunctional or higher (meth)acrylate compound exceeds 20 mass%, the following (i) to (iii): (i) The curing heat generated when the curable artificial nail composition is cured is too high. (ii) The cured film becomes too hard and loses flexibility, which reduces its ability to conform to the nail, causing lifting and chipping. (iii) specific odor problems; There is a risk of one of the following. If the (f) tri- or higher functional (meth)acrylate compound is less than 1% by mass, the reaction rate of the curable artificial nail composition cannot be improved, and curing may take a long time and / or may not be complete.

[0050] [(g) Other ingredients] The curable artificial nail composition of the present invention may contain various components as “(g) other components” in addition to the components (a) to (f) above, within a range that does not adversely affect storage stability, curability, color tone of the cured coating film, durability of the cured coating film, adhesion of the cured coating film, viscosity, handleability, coatability, etc. (g) Other components include, for example, one or more selected from the group consisting of various additives such as radical polymerizable compounds other than (a) to (d) and (f), resins, polyfunctional thiol compounds, polymerization inhibitors, colorants, polyol compounds, solvents, plasticizers, fragrances, anti-settling agents such as alumina, silicone-based and fluorine-based antifoaming agents, silane coupling agents such as γ-glycidoxypropyltrimethoxysilane, polymerization accelerators such as tertiary amines, surface tension adjusters, flame retardants, antioxidants, ion adsorbents, stress reducers, preservatives, antibacterial agents, flexibility-imparting agents, waxes, halogen trapping agents, leveling agents, wetting improvers, and decorative materials.

[0051] <Radical polymerizable compounds other than (a) to (d) and (f)> The radical polymerizable compound other than (a) to (d) and (f) is not particularly limited as long as it is, for example, a difunctional or lower functional (meth)acrylate oligomer other than a urethane (meth)acrylate oligomer, or a difunctional or lower functional radical polymerizable compound.

[0052] Examples of the difunctional or less functional (meth)acrylate oligomer other than the urethane (meth)acrylate oligomer include one or more selected from the group consisting of an epoxy (meth)acrylate oligomer having a molecular chain generated by a ring-opening reaction of an epoxy group, an ester (meth)acrylate oligomer (a (meth)acrylate oligomer having an ester bond in the main skeleton), and an ether (meth)acrylate oligomer (a (meth)acrylate oligomer having an ether bond in the main skeleton).

[0053] Examples of the radically polymerizable compound having two or less functionalities include one or more compounds selected from the group consisting of vinyl group-containing compounds, allyl group-containing compounds, etc. Specific examples include one or more compounds selected from the group consisting of styrene, α-methylstyrene, vinyltoluene, α-chlorostyrene, vinyl acetate, vinyl propionate, methyl vinyl ether, ethyl vinyl ether, N-vinylpyrrolidone, vinylpyridine, allyl glycidyl ether, vinyl group-containing oligomers, allyl group-containing oligomers, etc.

[0054] Examples of the difunctional or less radically polymerizable compound include one or more (meth)acrylate compounds having one or two (meth)acryloyl groups, such as methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, neopentyl (meth)acrylate, phenyl (meth)acrylate, benzyl (meth)acrylate, isobornyl (meth)acrylate, adamantyl (meth)acrylate, cyclohexyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, and dicyclopentanyl (meth)acrylate; Hydroxyl group-containing (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, and pentaerythritol mono(meth)acrylate; nitrogen-containing alkyl (meth)acrylates such as N,N-dimethylaminoethyl (meth)acrylate, N,N-diethylaminoethyl (meth)acrylate, and Nt-butylaminoethyl (meth)acrylate; phosphate ester-based (meth)acrylates such as (meth)acryloyloxyethyl phosphate, (meth)acryloyloxypropyl phosphate, caprolactone-modified (meth)acryloyloxyethyl phosphate, ethyl (meth)acrylic acid hexanoate phosphate, and pentyl (meth)acrylic acid propanoate phosphate;Glycidyl (meth)acrylate, 4-(meth)acryloyloxymethyl-2-cyclohexyl-1,3-dioxolane, (2-methyl-2-ethyl-1,3-dioxolan-4-yl)methyl (meth)acrylate, cyclic trimethylolpropane formal (meth)acrylate, (2-isobutyl-2-methyl-1,3-dioxolan-4-yl)methyl (meth)acrylate, (2-methyl-2-methyl-1,3-dioxolan-4-yl)methyl (meth)acrylate, (1,4-dioxaspiro[4,5]decan-2-yl)methyl (meth)acrylate, tetrahydrofuran heterocycle-containing (meth)acrylates such as tetrahydrofurfuryl (meth)acrylate, tetrafurfuryl alcohol oligo(meth)acrylate, alkoxylated tetrahydrofurfuryl (meth)acrylate, (3-ethyloxetan-3-yl)methyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate glycidyl ether, (meth)acryloylmorpholine, N-(meth)acryloyloxyethylhexahydrophthalimide, pentamethylpiperidyl (meth)acrylate, N-(meth)acryloxysuccinimide, and N-(meth)acryloxyphthalimide;Ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, polypropylene di(meth)acrylate, ethoxylated polypropylene glycol di(meth)acrylate, ethoxylated propylene glycol di(meth)acrylate, 1,3-butanediol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, glycerin di(meth)acrylate, trimethylolpropane di(meth)acrylate, pentaerythritol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,6-hexanediol and at least one selected from the group consisting of di(meth)acrylate monomers such as phosphate ester di(meth)acrylates, such as di(meth)acrylate, ethoxylated bisphenol A di(meth)acrylate, propoxylated bisphenol A di(meth)acrylate (isopyridenediphenylbis(oxyhydroxypropyl methacrylate), etc.), isocyanuric acid di(meth)acrylate, propoxylated ethoxylated bisphenol A di(meth)acrylate, di(meth)acryloyloxyethyl phosphate, di(meth)acryloyloxypropyl phosphate, caprolactone-modified di(meth)acryloyloxyethyl phosphate, di(meth)acrylic acid ethyl hexanoate phosphate, and di(meth)acrylic acid pentyl propanoate phosphate.

[0055] <Resin> The resin is not particularly limited as long as it is a resin that is neither polymerizable nor a polyol compound, and examples thereof include one or more resins selected from the group consisting of polyurethane resins, polyester resins, polyamide resins, polyether resins, olefin resins, aromatic olefin resins, aromatic hydrocarbon resins, acrylic resins, vinyl chloride resins, vinyl acetate resins, polyvinyl alcohol resins, polyvinyl acetal resins, core-shell polymers, graft resins, and block resins.

[0056] <Multifunctional thiol compounds> The polyfunctional thiol compound that may be contained in the curable artificial nail composition of the present invention is not particularly limited as long as it is a compound having two or more thiol groups in the molecule. The polyfunctional thiol compound is blended as a chain transfer agent, curability modifier, crosslinking agent, and viscosity modifier for the curable artificial nail composition. By blending the polyfunctional thiol compound in the curable artificial nail composition, it is possible to suppress the remaining of uncured components on the surface of the cured coating film. Examples of polyfunctional thiol compounds include those obtained by reacting a compound having a thiol group or a group that becomes a thiol group upon reaction with a hydroxyl group of a polyol compound such as trimethylolpropane, pentaerythritol, dipentaerythritol, or ethylene glycol. Among these, trifunctional or tetrafunctional thiol compounds are preferred, and one or more selected from the group consisting of trimethylolpropane tris(3-mercaptopropionate), trimethylolpropane tristhioglycolate, trimethylolpropane tris(3-mercaptobutyrate), pentaerythritol tetrakisthioglycolate, pentaerythritol tetrakis(3-mercaptobutyrate), and pentaerythritol tetrakis(3-mercaptopropionate) are preferred.

[0057] <Polymerization inhibitor> The polymerization inhibitor is not particularly limited as long as it is a compound capable of inhibiting the polymerization of the (meth)acrylate compounds (a) and (b). For example, it may be one or more compounds selected from the group consisting of tocopherol-based compounds, quinone-based compounds, phenol-based compounds, catechol-based compounds, oxydiphenylamine-based compounds, nitroso-based compounds, nitrone-based compounds, nitrile-based compounds, hydrazyl-based compounds, and phenothiazine-based compounds. Among these, it is preferable to use tocopherol-based compounds and / or quinone-based compounds. The content of the polymerization inhibitor in the curable artificial nail composition of the present invention is not particularly limited. For example, it can be 1.0 mass % or less based on the total amount of the curable artificial nail composition. If the content of the polymerization inhibitor exceeds 1.0 mass %, uncured components may remain on the surface of the cured coating film of the curable artificial nail composition, which may increase the viscosity over time and reduce the applicability and handleability. If the composition does not contain a polymerization inhibitor, storage stability may be reduced.

[0058] <Coloring agent> The colorant may be one or more selected from the group consisting of pigments, luster materials, and dyes, and may be used in any amount to impart a desired color tone to the curable artificial nail composition. In particular, the colorant may be one or more selected from the group consisting of inorganic pigments, luster materials, organic pigments, and dyes used in nail coatings, and does not significantly inhibit curing by ultraviolet irradiation (light irradiation) or the like. Before curing, the curable artificial nail composition may contain not only pigments but also resin particles and decorative materials that can be incorporated into known curable artificial nail compositions.

[0059] The curable artificial nail composition of the present invention preferably contains a bluing agent to form a transparent cured coating film and prevent the cured coating film from yellowing. The bluing agent used in the present invention preferably contains a blue colorant and a reactive diluent. Examples of blue colorants include colorants containing one or more selected from the group consisting of Violet 201, Violet 401, Blue 1, Blue 2, Blue 201, Blue 202, Blue 203, Blue 204, Blue 205, Blue 403, Blue 404, Green 201, Green 202, Green 204, Green 205, Green 3, Green 401, and Green 402, and preferably colorants containing one or more selected from the group consisting of Violet 201, Violet 401, Blue 1, Blue 2, Blue 201, Blue 202, Blue 203, Blue 204, Blue 205, Blue 403, and Blue 404. Examples of reactive diluents include one or more selected from the group consisting of (b) (meth)acrylate monomers.

[0060] <Polyol compounds> The polyol compound functions as a diluent and an adhesion improver for the curable artificial nail composition. Examples of the polyol compound include one or more selected from the group consisting of alkyl polyols, polyester polyols, polyether polyols, acrylic polyols, polybutadiene polyols, and phenolic polyols. Among these, alkyl polyols, polyester polyols, and polyether polyols are preferred.

[0061] <Solvent> The solvent is not particularly limited as long as it can adjust the viscosity at the time of application by dilution. For example, one or more solvents selected from the group consisting of alcohols such as methanol, ethanol, propanol, n-butanol, and i-butanol; ketones such as acetone, methyl isobutyl ketone, methyl ethyl ketone, and cyclohexanone; cellosolves such as ethyl cellosolve; aromatic hydrocarbons such as toluene and xylene; glycol ethers such as propylene glycol monomethyl ether; acetates such as methyl acetate, ethyl acetate, and butyl acetate; and diacetone alcohol.

[0062] [Viscosity of Curable Artificial Nail Composition] The viscosity of the curable artificial nail composition of the present invention at 25°C can be, for example, from 0.1 Pa·s to 60.0 Pa·s. The viscosity is preferably 0.5 Pa·s or more, more preferably 0.7 Pa·s or more, and is preferably 55.0 Pa·s or less, more preferably 50.0 Pa·s or less. By achieving a viscosity within this range, a curable artificial nail composition can be obtained that is easy to apply with an applicator such as a brush or inkjet printer.

[0063] [Uses of the curable artificial nail composition] The curable artificial nail composition of the present invention is a composition for coating the surface of nails, similar to so-called common manicures and pedicures. The curable artificial nail composition of the present invention is particularly suitable for use as a gel nail, and can be used to form any of a base coat layer applied directly to the user's nail, a color coat layer applied on top of the base coat layer, and a top coat layer applied on top of that. Examples include a color coat layer imparted with a desired color tone, a color top coat layer imparted with a desired color tone, a clear top coat layer that may also be imparted with a desired color tone, and a clear top coat layer containing glitter (metal powder, metal flakes, metal oxide flakes, glass flakes, etc.). After applying the curable artificial nail composition of the present invention, small decorations or powders can be attached to the coating surface of the curable artificial nail composition before curing to enhance the design.

[0064] The curable artificial nail composition of the present invention forms a cured coating film that has high hardness and excellent durability, and the cured coating film has excellent machine pressure resistance evaluation. Even when the cured coating film is sanded, the occurrence of cracks and unevenness is suppressed, and a smooth surface can be formed. Therefore, the curable artificial nail composition can be suitably used as a curable artificial nail composition for forming a base layer in a fill-in type gel nail.

[0065] [Coating of nails with curable artificial nail composition] The nails to be coated with the curable artificial nail composition of the present invention may be human fingernails or toenails, or may be the nails of animals such as dogs and cats. Furthermore, they may be artificial nails such as nail tips (false nails). When the curable artificial nail composition of the present invention is applied to a nail or an (un)cured coating film on the nail to form a coating, the applied surface may or may not be sanded. The method for applying the curable artificial nail composition is not particularly limited, and for example, an application tool such as a brush or an application method such as an inkjet can be used. The curable artificial nail composition of the present invention can be suitably used as a curable artificial nail composition for forming a base layer in a fill-in type gel nail. In this case, when replacing a gel nail with a new one, the base gel is left behind without removing the entire gel nail, and the upper layer of the base gel is sanded with a sanding machine, and a new gel nail is then applied on top of that, thereby forming a new gel nail.

[0066] An uncured coating film layer having the shape of a nail or the like can be formed on at least one surface of a sheet using the curable artificial nail composition of the present invention, and after contacting (transferring) this layer with the nail surface, the layer can be cured by irradiating with ultraviolet light, with or without peeling off the sheet. By using a method in which an uncured coating film layer is first formed on the surface of a sheet using a curable artificial nail composition and then transferred, it is possible to coat the nail surface with a uniform and accurate pattern without using an applicator such as a brush, and there is no need to clean the applicator after use.

[0067] The means for curing the curable artificial nail composition after application is not particularly limited as long as it is a means capable of imparting energy that causes the curing of the curable artificial nail composition. Examples include irradiation with energy rays such as light (ultraviolet (UV) rays, etc.), electron beams, and heat. Curing by irradiation with ultraviolet (UV) rays is particularly preferred because it can be carried out relatively quickly and easily. When curing by irradiation with light such as UV rays, a known UV curing device is used. Although the amount of energy required for curing varies depending on the composition of the curable artificial nail composition, for example, when curing by irradiation with light such as UV rays, the irradiation energy (integral light amount) by light irradiation is, for example, 5 mJ / cm. 2 or more, preferably 10 mJ / cm 2 or more, for example, 1000 mJ / cm 2 Less than or equal to 800 mJ / cm 2 If the irradiation energy is within this range, nail art with sufficient adhesion and abrasion resistance can be obtained.

[0068] Examples of light sources that can be used for irradiating light include known ultraviolet light sources such as multi-type UV lamps (UV+LEDs), mercury lamps, metal halide lamps, ultraviolet light-emitting diodes (UV-LEDs), and ultraviolet laser diodes (UV-LDs). Among these, from the viewpoints of compact size, long life, high efficiency, and low cost, multi-type lamps (UV+LEDs) (three-line dominant wavelength: about 365 nm, about 405 nm, and about 436 nm), ultraviolet light-emitting diodes (UV-LEDs; wavelength: about 385 nm to about 415 nm; peak wavelength: about 405 nm), and ultraviolet laser diodes (UV-LDs) are preferred. [Example]

[0069] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, "%" means "% by mass" and "parts" means "parts by mass." The blending amounts in Tables 1 to 3 are in parts by mass.

[0070] [Examples 1 to 7, Comparative Examples 1 to 20] The components shown in Tables 1 to 3 were placed in a container in the amounts (parts by mass) shown in Tables 1 to 3, respectively, and heated to 50° C. while stirring with a dissolver. The mixture was degassed for 10 minutes under a pressure of 0.1 MPa while stirring, and then left to stand at 50°C for 2 hours to further degas, yielding a curable artificial nail composition. All of these steps were performed in the dark.

[0071] <Ingredients> The components in Tables 1 to 3 are as follows: a1: Difunctional polyether polyurethane (meth)acrylate oligomer (weight average molecular weight 21,000) a2: Difunctional polycarbonate-based polyurethane (meth)acrylate oligomer (weight average molecular weight 21,000) b1: Difunctional polyether polyurethane (meth)acrylate oligomer (weight average molecular weight 1,600) c1: Isobornyl methacrylate d1: dimethylacrylamide e1: 2,4,6-trimethylbenzoyldiphenylphosphine oxide e2: 1-hydroxycyclohexyl phenyl ketone f1: Trimethylolpropane trimethacrylate f2: Trimethylolpropane triacrylate g1: A mixture containing 2-acryloyloxyethyl phosphate and bis(2-acryloyloxyethyl) phosphate g2: Isobornyl acrylate g3: hydroxyethyl methacrylate

[0072] <Temperature rise during curing> The temperature rise during curing of each of the obtained curable artificial nail compositions was measured as follows. The temperature at the start of measurement was measured using a temperature measuring device during curing attached to a cure shrinkage meter (manufactured by Acroedge, product name "Custron"), and the temperature during curing was measured, and the maximum temperature was taken as the maximum curing heat. The samples used in measuring maximum heat of cure were prepared as follows. A substrate fixing jig was provided above the ultraviolet light source, and a transparent glass substrate was fixed to the substrate fixing jig. A hole with a diameter of 1.0 mm was drilled in a fluororesin plate to prepare a fluororesin ring. The prepared fluororesin ring was placed on a transparent glass substrate, and the perforated portion was filled with the curable artificial nail composition so that the film thickness before curing was 1.00±0.05 mm. The fluororesin ring was then covered with a light-shielding material (black aluminum foil) to prepare a sample. The sample was irradiated with ultraviolet light from the transparent glass substrate side to cure the curable artificial nail composition filled in the perforated portion of the fluororesin ring, and the maximum curing heat generated during curing was measured. Using the obtained maximum curing heat, the following formula is calculated: Temperature rise during curing (℃) = Maximum curing heat (℃) - Measurement start temperature (℃) The temperature rise during curing was calculated using the above formula. The results are shown in Tables 1 to 3. In the present invention, a temperature of 32.0°C or less is acceptable.

[0073] <Strain rate 6% stress> The resulting curable artificial nail composition was applied to a hard vinyl chloride plate and cured by irradiating it with a 36 W LED lamp (irradiation wavelength: 405 nm) for 30 seconds to obtain a cured coating film with a thickness of 100 μm. The resulting cured coating film was peeled off and subjected to a tensile test in accordance with JIS K 7161:2014 to measure the 6% strain stress (MPa) of the cured coating film, which is the stress at a strain rate of 6%. The results are shown in Tables 1 to 3. In the present invention, a strength of 5.0 MPa or more is acceptable.

[0074] <Peel-off load> The adhesion of the obtained curable artificial nail composition was evaluated based on the peel-off load. The peel-off load was measured by a 90° peel-off test as follows. The results are shown in Tables 1 to 3.

[0075] (90° peel-off test) The surface of the nylon plate was wiped with ethanol to remove any dirt, and then the curable artificial nail composition was applied so that the cured film thickness was 100 μm. It was cured for 30 seconds with a 30 W LED light to form a cured coating film 10 mm long and 50 mm wide. The widthwise edge of the cured coating film was clamped with clips attached to a digital force gauge (Imada, ZTA-100N), and the cured coating film was peeled off from the nylon plate at 100 mm / sec in the widthwise direction at a peel angle of 90°, and the peel-off load (the maximum load (kg) required to peel off the cured coating film) was measured. The results are shown in Tables 1 to 3. In the present invention, 0.3 kg or more is acceptable.

[0076] <Water resistance evaluation> The surface of a polypropylene clear file was wiped with ethanol to remove any dirt, and then the curable artificial nail composition was applied using a doctor blade coater to a film thickness of 100 μm after curing. After curing for 30 seconds under a 30 W LED light, the composition was cut to form test specimens with a length of 50 mm to 60 mm and a width of 10 mm, each with a cured coating. A portion of the cured coating film from the test piece prepared above was immersed in water at 20°C ± 3°C for 2 hours, then removed, wiped dry, and placed on black drawing paper. The condition of the cured coating film was visually observed and evaluated according to the following criteria. The results are shown in Tables 1 to 3. In the present invention, A or B is acceptable. (Water resistance evaluation standard) A: The cured coating film in the water-impregnated area becomes slightly cloudy, but the condition underneath can be seen. B: The cured coating film in the water-impregnated area becomes cloudy, but the condition underneath the cured coating film can be seen. C: The cured coating film in the water-impregnated area was cloudy white, making it impossible to see the condition underneath the cured coating film.

[0077] [Table 1]

[0078] [Table 2]

[0079] [Table 3]

[0080] From Examples 1 to 7, it can be seen that the curable artificial nail composition according to the present invention containing components (a) to (e) is (i) The temperature rise during curing is 32.0°C or less, particularly 31.0°C or less, so that heat generation from the coating film during curing (curing by UV irradiation) is suppressed and the user is prevented from feeling heat; (ii) When the cured coating film is subjected to a tensile test, the stress at a strain rate of 6% (the stress at which the strain rate reaches 6% in a tensile test) is 5.0 MPa or more, which means that the film has excellent impact resistance and can prevent plastic deformation, lifting, and chipping of the cured coating film. (iii) The peel-off load (peel-off load in a 90° peel-off test) is 0.3 kg or more, demonstrating excellent adhesion to the substrate (nail). (iv) It has excellent water resistance and moisture does not easily penetrate or accumulate in the cured coating film, resulting in excellent durability of the cured coating film. It is clear that this is a

[0081] On the other hand, in the case of curable artificial nail compositions that do not contain component (b) (Comparative Examples 1 to 3, 7 to 20), in the case of curable artificial nail compositions that do not contain component (d) (Comparative Examples 7, 9, 10, 12), and in the case of curable artificial nail compositions in which the content of component (c) is outside the range of the present invention (Comparative Examples 4 to 6, 12), (i) The temperature rises during curing to over 32.0°C, causing the user to feel heat when creating a cured coating film. (ii) The stress at 6% strain (the stress when the strain rate reaches 6% in a tensile test) becomes less than 5.0 MPa, which reduces the impact resistance of the cured coating film. (iii) The peel-off load (peel-off load in a 90° peel-off test) is less than 0.3 kg, resulting in a decrease in the adhesion of the cured coating film. (iv) The water resistance rating becomes C, and the water resistance decreases. It can be seen that either one or more of the following is true.

[0082] From this, it can be seen that the curable artificial nail composition of the present invention suppresses the temperature rise during curing, and provides a cured coating film with excellent impact resistance, excellent adhesion, and excellent water resistance.

Claims

1. (a) one or more urethane (meth)acrylate oligomers having a weight average molecular weight of 5,000 or more; (b) one or more urethane (meth)acrylate oligomers having a weight average molecular weight of 1,000 or more and less than 5,000; (c) one or more alicyclic monofunctional methacrylate compounds; (d) one or more (meth)acrylamide compounds; (e) a polymerization initiator, Contains the content of the (c) alicyclic monofunctional methacrylate compound is 5.0% by mass or more and 25.0% by mass or less, based on 100% by mass of the total amount of the curable artificial nail composition; Curable artificial nail composition.

2. 2. The curable artificial nail composition according to claim 1, wherein the urethane (meth)acrylate oligomer (a) and / or the urethane (meth)acrylate oligomer (b) contains a polyether-based urethane (meth)acrylate oligomer and / or a polycarbonate-based urethane (meth)acrylate oligomer.

3. The curable artificial nail composition according to claim 1 or 2, further comprising (f) one or more trifunctional or higher functional (meth)acrylate compounds.

4. 3. The curable artificial nail composition according to claim 1, wherein the (meth)acrylamide compound (d) comprises dimethylacrylamide and / or hydroxyethylacrylamide.

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