Hardened artificial claw components

Abstract

To provide a curable artificial nail composition that is suppressed in rise temperature during curing, has no risk of giving the users a heat feeling (a pain due to heat) or discomfort or anxiety, and has excellent curability.SOLUTION: A curable artificial nail composition contains (1) an urethane methacrylate oligomer having a polycarbonate skeleton with a mass average molecular weight of 30,000 or less and 1,000 or more, (2) a non-polymerizable organic polymer, (3) a methacrylic monomer with a mass average molecular weight of less than 1,000, and (4) a polymerization initiator.SELECTED DRAWING: None

Description

Technical Field

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

Background Art

[0002] The popularity of nail art, which involves decorating natural nails on the hands and feet or attaching artificial nails and decorating them, is increasing. Also, artificial nails are formed on the nails for reinforcement to prevent cracking and peeling of the nails due to external forces. For such nail decoration and reinforcement, resin-containing materials called so-called manicure, pedicure, and sculptura are applied to the nails.

[0003] Recently, as a material used for nail decoration or reinforcement, a photocurable artificial nail composition called gel nail has attracted attention. Gel nail is a photocurable gel-like nail coating material (photocurable artificial nail composition), and for example, those containing a (meth)acrylate-based oligomer and a (meth)acrylic monomer are known. Gel nail is applied to the nails and cured by irradiating with ultraviolet rays, and it is said that a tough film that is difficult to peel off from the nails can be formed by a radical polymerization reaction to form a crosslinked polymer film.

[0004] So far, curable artificial nail compositions such as gel nails have been mainly studied from the viewpoints of adhesion of the cured coating film to the substrate (adhesive force to the nails), adhesion persistence, curability, aesthetic appearance of the cured coating film, etc. As a result, it has become possible to make these characteristics within a certain practical range. On the other hand, the cured heat (polymerization heat) generated when the conventional photocurable artificial nail composition undergoes photopolymerization to form a cured coating film has not been examined in detail regarding the temperature rise during curing. And there was a risk that the temperature rise during curing would give the user a heat sensation (pain due to heat), discomfort, or a sense of horror. Therefore, there is a need for a curable artificial nail composition that possesses characteristics such as adhesion of the cured coating film to the substrate (adhesion to the nail), adhesion durability, curability, and aesthetic appeal of the cured coating film, and furthermore, a low temperature rise during curing.

[0005] The following studies have been conducted regarding the temperature rise during curing when gel nails are photopolymerized. Patent Document 1 describes an auto-nail base coat composition containing a urethane acrylate oligomer, a monomer component containing at least hydroxyethyl acrylamide and 2-hydroxyethyl methacrylate, a photopolymerization initiator, and a polymer component. The heat generated during curing of this composition is evaluated in three stages (high, medium, and low), but the specific temperature is unknown. Patent Document 2 describes a photocurable artificial nail composition containing a urethane (meth)acrylate oligomer, a polyfunctional thiol compound, a radical polymerizable compound, a photopolymerization initiator, and a chain transfer agent. The temperature rise during curing of this composition is evaluated on a three-point scale: "not felt," "slightly felt," and "felt as heat pain," but the specific temperature is unknown. These patent documents 1 and 2 only describe the sensitive evaluation of the temperature rise during curing of a curable artificial nail composition. They do not describe or suggest controlling the range of the temperature rise during curing to a specific range, nor do they describe controlling the temperature rise during curing from the perspective of the composition of the curable artificial nail composition. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2018-80129 [Patent Document 2] Japanese Patent Publication No. 2019-6689 [Overview of the project] [Problems that the invention aims to solve]

[0007] The problem that this invention aims to solve is to provide a curable artificial nail composition that exhibits excellent curability, has a low temperature rise during curing, does not pose a risk of causing the user a feeling of heat (pain due to heat), discomfort, or fear. [Means for solving the problem]

[0008] The inventors of this invention conducted diligent research to solve the above problems and found that the above problems can be solved by creating a curable artificial nail composition with a specific composition, thus completing the present invention. Specifically, it is as follows: Item 1: (1) Urethane (meth)acrylate oligomer having a polycarbonate backbone, with a mass-average molecular weight of 30,000 or less and 1,000 or more. (2) non-polymerizable organic polymer, (3) (meth)acrylic monomers with a mass-average molecular weight of less than 1,000 (4) Polymerization initiator, A hardening artificial nail composition containing [the specified ingredient]. Item 2: The curable artificial nail composition according to Item 1, wherein the polymerization initiator is an α-hydroxyalkylphenone-based polymerization initiator. Item 3: The curable artificial nail composition according to item 1 or 2, wherein the mass ratio of (1) to (2) is (1) / (2) = 2 / 98 to 60 / 40. Item 4: A curable artificial nail composition according to any one of items 1 to 3, wherein the temperature rise during curing is 23°C or less. [Effects of the Invention]

[0009] The present invention provides a curable artificial nail composition that exhibits excellent curability, has a low temperature rise during curing, does not pose a risk of causing the user a feeling of heat (pain due to heat), discomfort, or fear. The curable artificial nail composition of the present invention exhibits remarkable effects, including a low temperature rise during curing, no risk of causing the user a feeling of heat (pain due to heat), discomfort, or fear, and excellent curability. [Modes for carrying out the invention]

[0010] The curable artificial nail composition of the present invention is described below. The curable artificial nail composition of the present invention hardens when energy is applied. Examples of the curable artificial nail composition of the present invention include, but are not particularly limited to, photocurable artificial nail compositions that harden when irradiated with light such as ultraviolet light (UV). The curable artificial nail composition of the present invention contains (1) a urethane (meth)acrylate oligomer having a polycarbonate skeleton with a mass average molecular weight of 35,000 or less and 1,000 or more, (2) a non-polymerizable organic polymer, (3) a (meth)acrylic monomer with a mass average molecular weight of less than 1,000, and (4) a polymerization initiator.

[0011] The inventors have found that reducing the number of reaction sites (polymerizable unsaturated groups and acryloyl groups) in the components constituting the curable artificial nail composition reduces the heat of curing and lowers the temperature rise during curing. On the other hand, they have also found that simply reducing the number of reaction sites (polymerizable unsaturated groups and acryloyl groups) in the components constituting the curable artificial nail composition may prevent the curable artificial nail composition itself from curing. Based on these findings, further investigations have shown that by providing a curable artificial nail composition containing (1) a urethane (meth)acrylate oligomer having a polycarbonate skeleton with a mass average molecular weight of 35,000 or less and 1,000 or more, (2) a non-polymerizable organic polymer, (3) a (meth)acrylic monomer with a mass average molecular weight of less than 1,000, and (4) a polymerization initiator, and more preferably by setting the mass ratio of (1) and (2) within a specific range, the heat of curing is reduced, the temperature rise during curing is lower, and the curability of the curable artificial nail composition itself is not affected. Furthermore, the inventors have found that when the curing temperature rise exceeds 23°C, the number of users experiencing heat sensation (pain due to heat) increases. Therefore, they have found that controlling the curing temperature rise of the curable artificial nail composition to 23°C or lower is effective as a criterion for reducing the risk of causing heat sensation (pain due to heat), discomfort, or fear in users. In this specification, the curing temperature rise is obtained by the method described in the examples.

[0012] <(1) A urethane (meth)acrylate oligomer having a polycarbonate skeleton> The urethane (meth)acrylate oligomer having a polycarbonate skeleton is not particularly limited as long as it has a mass average molecular weight of 1,000 or more and 35,000 or less, has a polycarbonate skeleton in the molecule, and has one or more urethane bonds and (meth)acryloyl groups. In particular, using a urethane methacrylate oligomer with a large steric hindrance is advantageous for reducing the curing heat. By blending a urethane (meth)acrylate oligomer having a polycarbonate skeleton, a high adhesive force can be imparted to the cured coating film of the curable artificial nail composition, and the strain caused by external impact, nail growth, etc. can be absorbed.

[0013] The mass average molecular weight of the urethane (meth)acrylate oligomer having a polycarbonate skeleton is 35,000 or less, preferably 33,000 or less, more preferably 32,000 or less, still more preferably 30,000 or less, and 1,000 or more, preferably 3,000 or more, more preferably more than 5,000, still more preferably 10,000 or more. By setting the mass average molecular weight within such a range, the durability of the cured coating film can be improved while maintaining a low viscosity.

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

[0015] The urethane (meth)acrylate oligomer having a polycarbonate skeleton is not particularly limited, and examples thereof include (meth)acrylate oligomers having urethane bonds and polycarbonate units in the main skeleton (main chain). (Meth)acrylate oligomers having a polycarbonate skeleton may be either commercially available products or synthetic products.

[0016] (Meth)acrylate oligomers having a polycarbonate skeleton can be synthesized, for example, by forming an isocyanate group-containing urethane prepolymer through the reaction of a polycarbonate polyol and a polyisocyanate, and reacting the isocyanate group-containing urethane prepolymer with a compound having an active hydrogen-containing group and a (meth)acryloyl group in the molecule (such as hydroxyalkyl (meth)acrylate, (meth)acrylic acid, etc.), but is not limited to this method. Examples of commercially available products of (meth)acrylate oligomers having a polycarbonate skeleton include, but are not limited to, one or more selected from the group consisting of SUA TH1 (manufactured by KSM), UV-3310B (manufactured by Mitsubishi Chemical), UN-9000PEP, UN-9200A, AU-2040 (manufactured by Tokushiki), KUA-PC2I (manufactured by KSM), etc.

[0017] In the curable artificial nail composition of the present invention, the content of (1) the (meth)acrylate oligomer having a polycarbonate skeleton is, for example, 3% by mass or more, preferably 20% by mass or more, more preferably 40% by mass or more, and for example, 85% by mass or less, preferably 80% by mass or less, more preferably 75% by mass or less when the total of (1) to (4) components is 100% by mass. If the content is less than 30% by mass, the viscosity of the curable artificial nail composition may become too low, and there is a risk that the coating property and handling property may deteriorate. If the content exceeds 85% by mass, the viscosity of the curable artificial nail composition may become too high, and there is a risk that the coating property, handling property, etc. may deteriorate, and there is a risk of deterioration of the leveling property of the coating film and deterioration of smoothness due to foam entrainment, etc.

[0018] <(2) Non-polymerizable organic polymer> The non-polymerizable organic polymer is not particularly limited as long as it is an organic polymer that does not have a polymerizable group such as a (meth)acrylate group or a vinyl group in the molecule and does not participate in the radical polymerization reaction. Furthermore, the mass-average molecular weight of the non-polymerizable organic polymer is not particularly limited. For example, it may be 1,000 or more, preferably 2,000 or more, more preferably 2,500 or more, and for example, 22,000 or less, preferably 20,000 or less, more preferably 10,000 or less, and may be an oligomer or a polymer (resin).

[0019] Examples of non-polymerizable organic polymers include resins such as polyurethane resins, polyester resins, polyether resins, polyamide resins, aliphatic olefin resins, aromatic hydrocarbon resins, (meth)acrylic resins, vinyl halogen resins, vinyl acetate resins, polyvinyl alcohol resins, polyvinyl acetal resins, core-shell polymers, graft resins, and block resins; and oligomers such as polyurethane oligomers, polyester oligomers, polyether oligomers, polyamide oligomers, aliphatic olefin oligomers, aromatic hydrocarbon oligomers, (meth)acrylic oligomers, vinyl halogen oligomers, vinyl acetate oligomers, polyvinyl alcohol oligomers, polyvinyl acetal oligomers, core-shell oligomers, graft oligomers, and block oligomers; one or more selected from this group.

[0020] In the curable artificial nail composition of the present invention, (2) the content of non-polymerizable organic polymer is, for example, 1% by mass or more, preferably 3% by mass or more, more preferably 5% by mass or more, and for example, 50% by mass or less, preferably 45% by mass or less, and more preferably 40% by mass or less, when the total of components (1) to (4) is 100% by mass. If the content is less than 1% by mass, it will not be possible to lower the temperature rise during curing of the curable artificial nail composition, which may cause the user to feel heat (pain due to heat), discomfort, or fear. If the content exceeds 50% by mass, the curability of the curable artificial nail composition may be poor. Furthermore, in the curable artificial nail composition of the present invention, the mass ratio of (1) a urethane (meth)acrylate oligomer having a polycarbonate skeleton and (2) a non-polymerizable organic polymer is preferably in the range of (1) / (2) = 2 / 98 to 60 / 40, more preferably 10 / 90 to 60 / 40.

[0021] <(3) (meth)acrylic monomers with a mass-average molecular weight of less than 1,000> (Meth)acrylic monomers with a mass-average molecular weight of less than 1,000 are monomers having one or more (meth)acryloyl groups and are not particularly limited as long as their mass-average molecular weight (molecular weight) is less than 1,000. The number of (meth)acryloyl groups contained in one molecule is not particularly limited, but from the viewpoint of the temperature rise during curing of the curable artificial nail composition, curability, etc., it is 1 to 10, preferably 1 to 8, and more preferably 1 to 6. In the present invention, it is preferable to use one or more (meth)acrylate monomers selected from those having one (meth)acryloyl group as the (meth)acrylate monomer. It is also preferable to use a mixture of one or more (meth)acrylate monomers having one (meth)acryloyl group and one or more (meth)acrylate monomers having two or more (meth)acryloyl groups.

[0022] Examples of (meth)acrylate monomers having one (meth)acryloyl group include 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, cyclohexyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, isobornyl (meth)acrylate, phenyl (meth)acrylate, benzyl (meth)acrylate, etc., esterified with (meth)acrylic acid; 2-hydroxyethyl (meth)acrylate, 1-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 1-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate Hydroxyalkyl (meth)acrylates such as t)acrylate, 3-hydroxybutyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 1-hydroxybutyl (meth)acrylate, and hydroxyphenoxypropyl (meth)acrylate; polyol (meth)acrylates such as trimethylolpropane (meth)acrylate, pentaerythritol (meth)acrylate, dipentaerythritol (meth)acrylate, and ditrimethylolpropane (meth)acrylate; (meth)acrylates having alkylene glycol chains such as diethylene glycol mono(meth)acrylate, triethylene glycol mono(meth)acrylate, tetraethylene glycol mono(meth)acrylate, dipropylene glycol mono(meth)acrylate, tripropylene glycol mono(meth)acrylate, dibutylene glycol mono(meth)acrylate, and tributylene glycol mono(meth)acrylate;(meth)acrylamide, hydroxyethyl(meth)acrylamide, dimethyl(meth)acrylamide, diethyl(meth)acrylamide, N-methyl(meth)acrylamide, N-hydroxyethyl(meth)acrylamide, N-ethyl(meth)acrylamide, N-methylol(meth)acrylamide, N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N,N-dimethylaminopropyl(meth)acrylamide, N,N-dimethylaminoethyl(meth)acrylamide, N,N-dipropyl(meth)acrylamide, N,N-diisopropyl(meth)acrylamide (meth)acryloyl group-containing amide compounds such as N,N-dibutyl(meth)acrylamide, N,N-diisobutyl(meth)acrylamide, N,N-di-tert-butyl(meth)acrylamide, N,N-diheptyl(meth)acrylamide, N,N-dioctyl(meth)acrylamide, N,N-di-tert-octyl(meth)acrylamide, N,N-didodecyl(meth)acrylamide, and N,N-dioctadecyl(meth)acrylamide; nitrogen-containing alkyl(meth)acrylates such as N,N-dimethylaminoethyl(meth)acrylate and N,N-diethylaminoethyl(meth)acrylate;Adamantyl (meth)acrylate, (2-methyl-2-ethyl-1,3-dioxolan-4yl)methyl (meth)acrylate, 4-(meth)acryloyloxymethyl-2-cyclohexyl-1,3-dioxolane, (2-isobutyl-2-methyl-1,3-dioxolan-4yl)methyl (meth)acrylate, cyclic trimethylolpropaneformal (meth)acrylate, (1,4-dioxaspiro[4,5]decane-2yl)methyl (meth)acrylate, tetrafurfuryl alcohol oligo(meth)acrylate, alkoxylated tetrahydrofurfuryl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate One or more heterocyclic (meth)acrylates selected from the group consisting of (3-ethyloxetane-3-yl)methyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate glycidyl ether, glycidyl (meth)acrylate, (meth)acryloylmorpholine, N-(meth)acryloyloxyethylhexahydrophthalimide, pentamethylpiperidyl (meth)acrylate, di(meth)acrylate isocyanurate, tri(meth)acrylate isocyanurate, triazine tri(meth)acrylate, N-(meth)acrylooxysuccinimide, N-(meth)acrylooxyphthalimide, etc., are examples.

[0023] Of these (meth)acrylate monomers having one (meth)acryloyl group, it is preferable to select one or more from the group consisting of esters of monohydric alcohols 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, cyclohexyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, isobornyl (meth)acrylate and (meth)acrylic acid, hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, and heterocyclic (meth)acrylates such as (meth)acryloylmorpholine.

[0024] Examples of (meth)acrylate monomers having two or more (meth)acryloyl groups include ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, polyethylene glycol (meth)acrylate, propylene glycol di(meth)acrylate, polypropylene di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, glycerin di(meth)acrylate, trimethylolpropane di(meth)acrylate, and ditrimethylolpropane. Di(meth)acrylate, pentaerythritol di(meth)acrylate, dipentaerythritol di(meth)acrylate, neopentyl glycol di(meth)acrylate, bisphenol A ethylene oxide modified di(meth)acrylate, ethoxylated bisphenol A di(meth)acrylate, propoxylated bisphenol A di(meth)acrylate (isopyridene diphenylbis(oxyhydroxypropyl methacrylate), etc.), propoxylated ethoxylated bisphenol A di(meth)acrylate, alkylene oxide added trimethyl Di(meth)acrylate monomers such as dolpropane di(meth)acrylate; glycerin tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, ditrimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, ε-caprolactone modified tris(acryloxyethyl) isocyanurate, tri(meth)acrylate monomers such as alkylene oxide-added pentaerythritol tri(meth)acrylate; tetra(meth)acrylate such as pentaerythritol tetra(meth)acrylate (Meth)acrylate monomers having five or more (meth)acrylate groups, such as polypentaerythritol (meth)acrylates including dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, tripentaerythritol (meth)acrylate, and tetrapentaerythritol (meth)acrylate; ethoxylated isocyanuric acid triacrylate, ethoxylated pentaerythritol tetraacrylate, and alkylene oxide-added dipentaerythritol penta(meth)acrylate;One or more types can be selected from the group consisting of the following:

[0025] Of these (meth)acrylate monomers having two or more (meth)acryloyl groups, it is preferable to select one or more from the group consisting of ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, polypropylene di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, etc.

[0026] In the curable artificial nail composition of the present invention, (3) the (meth)acrylic monomer having a mass-average molecular weight of less than 1,000 preferably contains one of the following conditions (a) to (d): (a) low viscosity of 2 Pa·s or less, (b) three or fewer (meth)acryloyl groups per molecule, (c) polarized acrylamide, or (d) having a polar group such as a hydroxyl group.

[0027] In the curable artificial nail composition of the present invention, (3) the content of (meth)acrylic monomers having a mass-average molecular weight of less than 1,000 is, for example, 10% by mass or more, preferably 15% by mass or more, more preferably 20% by mass or more, and for example, 55% by mass or less, preferably 50% by mass or less, more preferably 45% by mass or less, when the total of components (1) to (4) is 100% by mass. If the content is less than 10% by mass, the viscosity of the curable artificial nail composition may become too low, which may result in poor applicability and handling. If the content exceeds 55% by mass, the viscosity of the curable artificial nail composition may become too high, which may result in poor applicability and handling, and furthermore, the temperature rise during curing may become too high, and the cured coating film may become too hard.

[0028] <(4) Polymerization initiator> Polymerization initiators generate radicals when energy is supplied by light (e.g., ultraviolet light) or heat irradiation. Examples include one or more polymerization initiators selected from the group consisting of acylphosphine oxides, α-hydroxyalkylphenones, benzoin ethers, benzyl ketals, acid esters, α-aminoalkylphenones, benzophenones, thioxanthones, titanocenes, quinones, peroxides, azos, and persulfates. For example, by using a photopolymerization initiator, good curability can be imparted to a curable artificial nail composition even when irradiated with light using various light sources, including UV-LED light sources.

[0029] For example, acylphosphine oxide polymerization initiators generate radicals when irradiated with ultraviolet light of a wavelength of 365-405 nm emitted from commonly used UV-LED light sources. Therefore, even when curing by irradiation with light using various light sources, including UV-LED light sources, good curability can be imparted to the curable composition. Furthermore, when curing by irradiation with 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 the like. In particular, 2,4,6-trimethylbenzoyldiphenylphosphine oxide can be preferably used in the present invention because it also functions as a skin conditioning agent.

[0030] Examples of polymerization initiators other than acylphosphine oxide-based 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, and 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 Ride, 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-diphenylethane-1-one,2-hydroxy-1-{4-[4-(2-hydroxy-2-methylpropionyl)-benzyl]phenyl}-2-methylpropane, isophthalphenone, methyl phenylglyoxyate, 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, benzyl 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-cyclohexanecarbonitride), 2,2'-Azobis(2-methylpropionitrile), 2,2′-Azobis(2-cyclopropylpropionitrile), 2,2′-Azobis(methylisobutyrate), t-butyl hydroperoxide, cumene hydroperoxide, diacetyl peroxide, didecanoyl peroxide Oxide, di-t-butyl peroxide, methyl ethyl ketone peroxide, cyclohexanone peroxide, dicumyl peroxide, di(3,5,5-trimethylhexanoyl) peroxide, dilauroyl peroxide, disaxinic acid peroxide, dibenzoyl peroxide, t-butyl peroxypivalate, t-butyl peroxybenzoate, t-hexyl peroxide parerate, 2,5-dimethyl-2,5-di(2-ethylhexanoylperoxy)hexane, 1,1,3,3-tetramethylbutyl Peroxy-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, 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane, 2,2-bis(t-butylperoxy)butane, 2,One or more substances selected from the group consisting of 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, ammonium persulfate, etc.

[0031] In the present invention, when curing the curable composition by irradiation with an LED lamp, it is preferable to use a polymerization initiator containing an acylphosphine oxide-based polymerization initiator. Furthermore, when curing the curable composition by irradiation with a UV lamp, it is preferable to use a polymerization initiator containing an α-hydroxyalkylphenone-based polymerization initiator. In the present invention, it is preferable to use a polymerization initiator that includes an acylphosphine oxide polymerization initiator and an α-hydroxyalkylphenone polymerization initiator. In this case, the mixing ratio of the two is preferably in the range of 1 / 0.5 to 1 / 4 as acylphosphine oxide polymerization initiator / α-hydroxyalkylphenone polymerization initiator. Furthermore, polymerization initiators containing acylphosphine oxide-based polymerization initiators, α-hydroxyalkylphenone-based polymerization initiators, and peroxide-based polymerization initiators can also be used.

[0032] In the curable artificial nail composition of the present invention, the content of the polymerization initiator is, for example, 0.1% by mass or more, preferably 0.5% by mass or more, more preferably 1.0% by mass or more, and for example, 10.0% by mass or less, preferably 7.0% by mass or less, and more preferably 5.0% by mass or less, when the total of components (1) to (4) is 100% by mass. If the content is less than 0.1% by mass, the curing of the curable artificial nail composition may take a long time to cure, and curing may be incomplete. If the content exceeds 10.0% by mass, the molecular weight of the cured coating film may decrease, making the cured coating film brittle, and the cured coating film of the curable artificial nail composition may yellow (discolor).

[0033] <Other ingredients> Various additives can be incorporated into the curable artificial nail composition, provided they do not adversely affect viscosity, usability, or the durability of the coating film. Examples of such additives include one or more compounds containing radically polymerizable unsaturated groups other than "(1) urethane (meth)acrylate oligomers having a polycarbonate skeleton with a mass average molecular weight of 30,000 or less and 1,000 or more, and (3) (meth)acrylic monomers with a mass average molecular weight of less than 1,000" (hereinafter sometimes referred to as "other radically polymerizable compounds"), colorants, polyfunctional thiol compounds, polyol compounds, polymerization inhibitors, resins, solvents, fragrances, silicone-based and fluorine-based defoamers, silane coupling agents such as γ-glycidoxypropyltrimethoxysilane, polymerization accelerators such as tertiary amines, chain transfer agents, fillers, surface tension modifiers, flame retardants, antioxidants, ion adsorbents, stress reducers, preservatives, antibacterial agents, flexibility imparters, waxes, halogen trapping agents, leveling agents, wetting improvers, and various other additives.

[0034] Other radically polymerizable compounds are not particularly limited as long as they contain radically polymerizable unsaturated groups other than "(1) urethane (meth)acrylate oligomers having a polycarbonate skeleton with a mass average molecular weight of 30,000 or less and 1,000 or more, and (3) (meth)acrylic monomers having a mass average molecular weight of less than 1,000." For example, these include urethane (meth)acrylate oligomers having a polycarbonate skeleton with a mass average molecular weight exceeding 30,000, (meth)acrylate oligomers other than urethane (meth)acrylate oligomers having a polycarbonate skeleton with a mass average molecular weight of 1,000 or more, or compounds having radically polymerizable unsaturated groups other than (meth)acryloyl groups. Radically polymerizable unsaturated groups are functional groups having a carbon-carbon double bond (also called polymerizable double bonds), and examples include vinyl groups, vinyl ether groups, and allyl groups.

[0035] Other radical polymerizable compounds include, for example, (i) (meth)acrylate oligomers having one or more types selected from the group consisting of urethane bonds, bonds formed by ring-opening reactions of epoxy groups, ester bonds, ether bonds, urea bonds, and amide bonds in the main skeleton (main chain), (ii) A (meth)acrylate oligomer having a molecular chain formed by polymerization of one or more monomers selected from the group consisting of styrene-based, (meth)acrylic-based, olefin-based, and diene-based monomers, (iii) A radical polymerizable compound having one or more radically polymerizable unsaturated groups other than (meth)acryloyl groups, such as vinyl groups, vinyl ether groups, and allyl groups. One or more types can be selected from the group consisting of the following.

[0036] The mass-average molecular weight of the (meth)acrylate oligomers in (i) and (ii) above is not particularly limited, but is, for example, 1,000 to 100,000, preferably 2,000 to 30,000, and more preferably 3,000 to 20,000. By setting the mass-average molecular weight within this range, it is possible to improve the durability of the cured coating film while maintaining low viscosity.

[0037] (i) As for (meth)acrylate oligomers having one or more selected from the group consisting of urethane bonds, bonds formed by ring-opening reactions of epoxy groups, ester bonds, ether bonds, urea bonds, and amide bonds in the main skeleton (main chain), for example, one or more selected from the group consisting of urethane (meth)acrylate oligomers ((meth)acrylate oligomers having urethane bonds as the main skeleton), epoxy (meth)acrylate oligomers having molecular chains formed by ring-opening reactions of epoxy groups, ester (meth)acrylate oligomers ((meth)acrylate oligomers having ester bonds as the main skeleton), ether (meth)acrylate oligomers ((meth)acrylate oligomers having ether bonds as the main skeleton), etc., are preferred in terms of adhesion and the like. (Meth)acrylate oligomers may be either commercially available or synthetically produced.

[0038] Urethane (meth)acrylate oligomers can be synthesized, for example, by forming an isocyanate group-containing urethane prepolymer by reacting a polyol with a polyisocyanate, and then reacting the isocyanate group-containing urethane prepolymer with a compound having an active hydrogen-containing group and a (meth)acryloyl group in its molecule (such as hydroxyalkyl (meth)acrylate or (meth)acrylic acid), but the synthesis method is not limited to this method. Commercially available products include, but are not limited to, one or more types selected from the group consisting of AH-600, AT-600, UA-306H, UF-8001G (manufactured by Kyoeisha Chemical Co., Ltd.) and RUA-071, RUA-003VE, RUA-075, RUA-048 (manufactured by Asia Chemical Industries Co., Ltd.).

[0039] The one or more urethane (meth)acrylate oligomers that can be used in the present invention can be selected from those having one or more selected from the group consisting of a non-aromatic polyether skeleton, an aromatic polyether skeleton, a non-aromatic polycarbonate skeleton, an aromatic polycarbonate skeleton, a non-aromatic polyester skeleton, and an aromatic polyester skeleton. Among these, those having one or more non-aromatic polyether skeletons are preferred.

[0040] A urethane (meth)acrylate oligomer having one or more non-aromatic polyether skeletons can be obtained by adding a (meth)acrylic compound having hydroxyl groups to an isocyanate group-containing polyether urethane prepolymer, and then performing an addition reaction with the (meth)acrylic compound having hydroxyl groups on 10% or more of the total number of isocyanate groups in the urethane prepolymer. Here, the isocyanate group-containing polyether urethane prepolymer is obtained by reacting a polyol compound having an alkylene group with 3 or more carbon atoms with a polyisocyanate, for example, having a mass-average molecular weight of 400 to 30,000. Polypropylene polyol is preferred as the polyol compound. As the polyisocyanate, one or more non-aromatic polyisocyanates are selected from the group consisting of isophorone diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, and their isocyanurates and biuret compounds.

[0041] Ester (meth)acrylate oligomers having ester bonds can be synthesized, for example, by adding a compound having a hydroxyl group and a (meth)acryloyl group, and / or an acrylic compound having a (meth)acrylic acid or a carboxyl group, to the carboxyl group and / or hydroxyl group of an ester oligomer obtained by the reaction of a polyol and a polycarboxylic acid, but the method is not limited to this. Commercially available products include, but are not limited to, one or more types selected from the group consisting of, for example, 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 (manufactured by Toagosei Co., Ltd.) and UV-3500BA, UV3520TL, UV-3200B, UV-3000B (manufactured by Mitsubishi Chemical Corporation).

[0042] Ether (meth)acrylate oligomers having an ether linkage can be synthesized, for example, by adding one or more compounds selected from the group consisting of compounds having a hydroxyl group and a (meth)acryloyl group in the molecule, (meth)acrylic acid, and compounds having a carboxyl group and a (meth)acryloyl group in the molecule to the hydroxyl group of an aliphatic polyether polyol or the hydroxyl group of an aromatic polyether polyol derived from bisphenol, etc., but the method is not limited to this method. Commercially available products include, but are not limited to, one or more types selected from the group consisting of, for example, UV-6640B, UV-6100B, UV-3700B (manufactured by Mitsubishi Chemical Corporation), LIGHT ACRYLATE® 3EG-A, 4EG-A, 9EG-A, 14EG-A, PTMGA-250, BP-4EA, BP-4PA, BP-10EA, LIGHT ESTER 4EG, 9EG, 14EG (manufactured by Kyoeisha Chemical Co., Ltd.), EBECRYL® 3700 (manufactured by Daicel-Scytec Corporation), etc.

[0043] (ii) Examples of (meth)acrylate oligomers having molecular chains formed by polymerization of one or more monomers selected from the group consisting of styrene-based, (meth)acrylic-based, olefin-based, and diene-based monomers include (meth)acrylate oligomers obtained by reacting one or more polymer polyols selected from the group consisting of polystyrene polyols, acrylic polyols, polyolefin polyols, conjugated diene polyols, etc., with a polyisocyanate, and then reacting with a (meth)acrylate compound having a functional group that can react with a hydroxyl group or an isocyanate group. Of these, urethane (meth)acrylate oligomers obtained by selecting one or more from the group consisting of acrylic polyols, polyolefin polyols, butadiene polyols, etc., as the polyol component are preferred. Other radical polymerizable compounds are compounds having one or more (meth)acryloyl groups or compounds having radically polymerizable unsaturated groups other than (meth)acryloyl groups. Radically polymerizable unsaturated groups are functional groups having a carbon-carbon double bond (also called polymerizable double bonds), and examples include vinyl groups, vinyl ether groups, and allyl groups.

[0044] (iii) Examples of radical polymerizable compounds having one or more unsaturated groups other than (meth)acryloyl groups that can be radically polymerized include vinyl groups, vinyl ether groups, allyl groups, etc., one or more selected from the group consisting of allyl glycidyl ether, styrene, α-methylstyrene, vinyltoluene, α-chlorostyrene, vinyl acetate, etc.

[0045] The content of other radical polymerizable compounds in the curable artificial nail composition is 0% by mass or more (including 0% by mass, i.e., not present) relative to the total amount of components of the curable artificial nail composition, for example, 60% by mass or less, preferably 50% by mass or less, and more preferably 40% by mass or less. If the content exceeds 60% by mass, the adhesive strength and durability of the cured coating film of the curable artificial nail composition and its adhesion to the substrate may deteriorate, and the viscosity of the curable artificial nail composition may become too low, resulting in poor applicability and handling.

[0046] The coloring agent is one or more selected from the group consisting of pigments, luminescent agents, and dyes, and is used in any amount to impart a desired color tone to the curable artificial nail composition. In particular, it is one or more selected from the group consisting of inorganic pigments, luminescent agents, organic pigments, and dyes used in nail coating materials, and does not significantly hinder curing when cured by ultraviolet irradiation (light irradiation), etc. The curable artificial nail composition before hardening can also contain not only pigments, but also resin particles and decorative materials that can be incorporated into known curable artificial nail compositions.

[0047] Examples of colorants include Brown No. 201, Black No. 401, Purple No. 201, Purple No. 401, Blue No. 1, Blue No. 2, Blue No. 201, Blue No. 202, Blue No. 203, Blue No. 204, Blue No. 205, Blue No. 403, Blue No. 404, Green No. 201, Green No. 202, Green No. 204, Green No. 205, Green No. 3, Green No. 401, Green No. 402, Yellow No. 201, Yellow No. 202-(1), Yellow No. 20 No. 2-(2), Yellow No. 203, Yellow No. 204, Yellow No. 205, Yellow No. 4, Yellow No. 401, Yellow No. 402, Yellow No. 403-(1), Yellow No. 404, Yellow No. 405, Yellow No. 406, Orange 201 No., Orange No. 203, Orange No. 204, Orange No. 205, Orange No. 206, Orange No. 207, Orange No. 401, Orange No. 402, Orange No. 403, Red No. 102, Red No. 104-(1), Red No. 105-(1 ), Red No. 106, Red No. 2, Red No. 201, Red No. 202, Red No. 203, Red No. 204, Red No. 205, Red No. 206, Red No. 207, Red No. 208, Red No. 213, Red No. 214, Red No. 215, Red No. 218, Red No. 219, Red No. 220, Red No. 221, Red No. 223, Red No. 225, Red No. 226, Red No. 227, Red No. 228, Red No. 230-(1), Red No. 23 One or more substances selected from the group consisting of 0-(2), Red No. 231, Red No. 232, Red No. 3, Red No. 401, Red No. 405, Red No. 501, Red No. 502, Red No. 503, Red No. 504, Red No. 505, Red No. 506, titanium dioxide, iron oxide, chromium oxide, manganese violet, carbon black, metal powder, metal flakes, metal oxide flakes, glass flakes, etc.

[0048] Polyfunctional thiol compounds are incorporated into curable artificial nail compositions as curing modifiers, crosslinking agents, and viscosity modifiers. Furthermore, incorporating polyfunctional thiol compounds into curable artificial nail compositions can improve the wipeability when removing the cured coating film. Examples of polyfunctional thiol compounds include those obtained by reacting a thiol group or a compound having a group that reacts to form a thiol group with the hydroxyl group of a polyol compound such as trimethylolpropane, pentaerythritol, or dipentaerythritol. For example, one or more compounds selected from the group consisting of trimethylolpropane tris(3-mercaptopropionate), tris[(3-mercaptopropionyloxy)-ethyl]-isocyanurate, pentaerythritol tetrakis(3-mercaptobutyrate), pentaerythritol tetrakis(3-mercaptopropionate), dipentaerythritol hexakis(3-mercaptopropionate), etc. When a polyfunctional thiol compound is included in a curable artificial nail composition, it is preferably included in an amount of 1.0 to 10.0% by mass.

[0049] Polyol compounds function as diluents and adhesion enhancers for curable artificial nail compositions. Examples of polyol compounds 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. Examples of alkyl polyols include one or more selected from the group consisting of ethylene glycol, 1,4-butanediol, 1,6-hexanediol, 1,8-octanediol, neopentyl glycol, cyclohexanedimethanol, trimethylolpropane, pentaerythritol, and the like.

[0050] Examples of polyester polyols include one or more selected from the group consisting of condensation-type polyester polyols, addition-polymerized polyester polyols, and polycarbonate polyols. Condensation-type polyester polyols are obtained by a condensation reaction between one or more diol compounds selected from the group consisting of ethylene glycol, propylene glycol, diethylene glycol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,9-nonanediol, 1,4-hexanedimethanol, dimer acid diol, polyethylene glycol, etc., and one or more organic polybasic acids selected from the group consisting of adipic acid, isophthalic acid, terephthalic acid, sebacic acid, etc., and a molecular weight of 100 to 100,000 is preferred. Examples of addition-polymerized polyester polyols include polycaprolactone, and a molecular weight of 100 to 100,000 is preferred. Polycarbonate polyols are synthesized by methods such as direct phosgenation of polyols or transesterification with diphenyl carbonate, and their molecular weight is preferably 100 to 100,000. Examples of polyether polyols include those obtained by open polymerization of alkylene oxides.

[0051] Polymerization inhibitors include, for example, one or more selected from the group consisting of quinone compounds, salicylic acid hydrazide, tocopherol compounds, and the like. When a polymerization inhibitor is included in the curable artificial nail composition, it can be blended in an amount of 500 to 5000 ppm, preferably 1000 to 4500 ppm, relative to the total curable artificial nail composition.

[0052] The solvent is not particularly limited as long as its viscosity during application can be adjusted by dilution. Examples include 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; acetic acid esters such as methyl acetate, ethyl acetate, and butyl acetate; and diacetone alcohol, among others.

[0053] <Uses and physical properties of hardened artificial nail compositions> The cured coating film of the curable artificial nail composition of the present invention exhibits excellent adhesion to the substrate, maintains its adhesion to the substrate for a long period of time, and has appropriate hardness. The curable artificial nail composition of the present invention is a composition for coating the surface of a nail, similar to so-called general manicures and pedicures, and may be used to coat the surface of the user's own nail, which may have been made uneven by sanding as needed. It is particularly suitable for use as a gel nail, and can be used, for example, as 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 the top coat. Furthermore, when used as a color coating layer, it can be used in a variety of colors by mixing colorants, including solid colors, glittery finishes, metallic finishes, dark colors, and light colors. When forming the cured coating film of the curable artificial nail composition of the present invention, equipment similar to that used for curing radical polymerizable curable compositions, such as general ultraviolet curing equipment or nail polish curing equipment, can be used.

[0054] The cured coating film of the curable artificial nail composition of the present invention has a suppressed content of unpolymerized curable components due to polymerization inhibition by oxygen, etc., and therefore eliminates the need for a wiping step using solvents such as ethanol, isopropanol, ethyl acetate, or acetone, especially ethanol. The curable artificial nail composition of the present invention, regardless of which layer it is used in, will not chip or peel off the cured coating for a long period of time (for example, at least two weeks after curing), and will also suppress lifting from the underlying layer or the user's nail.

[0055] The curable artificial nail composition of the present invention should have a viscosity that allows it to be sufficiently applied using an applicator such as a brush or an inkjet.

[0056] <Covering of nails using a hardening artificial nail composition> The nails covered with the curable artificial nail composition of the present invention may be human fingernails or toenails, or even animal nails such as those of dogs or cats. When applying the curable artificial nail composition of the present invention to a nail or a coating applied to a nail, sanding of the application surface is optional. The method of 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 inkjet printing can be used. The curable artificial nail composition of the present invention can be used as a base coat layer (gel base; undercoat), an intermediate layer (color layer), or a top coat layer in gel nails. In particular, it is preferable to use it as a base coat layer (gel base; undercoat) because of its excellent adhesion to the substrate. After applying the curable artificial nail composition of the present invention, it is also possible to enhance its aesthetic appeal by attaching small decorations, powders, etc., to the surface of the coating film of the curable artificial nail composition before it hardens.

[0057] Alternatively, a layer having the shape of a nail or the like can be prepared on one side of the sheet using the uncured curable artificial nail composition of the present invention, and after bringing this layer into contact with (transferring) the nail surface, the sheet can be peeled off or cured by irradiating it with ultraviolet light without peeling it off. By applying a layer of a curable artificial nail composition to the surface of a sheet in advance and then transferring it, it is possible to cover the surface of the nail 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.

[0058] The means for curing the curable artificial nail composition after application is not particularly limited, as long as it is a means that can impart energy to the curable artificial nail composition. For example, when curing by irradiation with light such as ultraviolet light, a known ultraviolet curing device is used. Although the amount of energy required for curing differs depending on the composition of the curable artificial nail composition, for example, when curing by irradiation with light such as ultraviolet light, the irradiation energy (integrated light amount) by light irradiation is, for example, 5 mJ / cm². 2 Preferably 10 mJ / cm² 2 That's all, for example, 1000 mJ / cm 2 Preferably 800 mJ / cm² 2 The following applies: If the irradiation energy is within this range, nail art with sufficient adhesion and abrasion resistance can be obtained. For the light source used for illumination, known ultraviolet light sources such as mercury lamps, metal halide lamps, ultraviolet light-emitting diodes (UV-LEDs), and ultraviolet laser diodes (UV-LDs) can be used. Among these, ultraviolet light-emitting diodes (UV-LEDs) and ultraviolet laser diodes (UV-LDs) are preferred from the viewpoint of being small, having a long lifespan, high efficiency, and low cost. [Examples]

[0059] 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 "mass%" and "parts" means "parts by mass".

[0060] <Examples 1-8, Comparative Examples 1-5> The components shown in Table 1 were added to a container in the proportions (parts by mass) shown in Table 1, and the mixture was heated to 50°C while being stirred with a dissolver. After stirring, the mixture was allowed to stand at 80°C for 2 hours to remove air bubbles, and a curable artificial nail composition was obtained. All of these steps were carried out under light shielding conditions.

[0061] The components in Table 1 are as follows: PUA-1: Urethane (meth)acrylate oligomer with a polycarbonate backbone (mass-average molecular weight 29,000) PUA-2: Urethane (meth)acrylate oligomer with a polycarbonate backbone (mass-average molecular weight 5,100) PUA-3: Polyether backbone urethane (meth)acrylate oligomer (weight-average molecular weight 4,000) NPOC: Polycarbonate polyurethane (non-polymerizable oligomer) M-1:2-Hydroxybutyl methacrylate M-2: Isobornyl acrylate M-3: Dimethylacrylamide I-1: 2,4,6-trimethylbenzoyldiphenylphosphine oxide I-2: 1-Hydroxycyclohexylphenyl ketone

[0062] The temperature rise during curing and curability of the obtained curable artificial nail composition were evaluated as follows. The results are shown in Table 1. <Temperature rise during curing> (Measurement of temperature rise during curing) The heat generated during curing was measured using the curing temperature measuring device attached to the curing shrinkage meter (product name Custron; manufactured by Acroedge). The samples used for measuring the heat of curing were prepared as follows. A substrate fixing jig was placed on top of an ultraviolet light source, and a transparent glass substrate was fixed to the substrate fixing jig. A Teflon® ring was fabricated by drilling a 1.0 mm diameter hole in a Teflon® plate. A Teflon® ring was placed on a transparent glass substrate, and a curable artificial nail composition was filled into the perforated area to a pre-curing film thickness of 1.0 ± 0.1 mm. The Teflon® ring was then covered with black aluminum foil (light-shielding material) to prepare a sample. The sample was cured by irradiating it with ultraviolet light from the transparent glass substrate side, and the curable artificial nail composition filled in the perforated portion of the Teflon® ring was cured. The heat generated during curing was then measured.

[0063] (Calculation of temperature rise during curing) Using the heat of curing obtained, the following formula (A): Curing temperature rise (°C) = Maximum curing heat (°C) - Starting temperature (°C) The temperature rise during curing was calculated using the method described above. In this invention, a product was deemed acceptable if the temperature rise during curing was 23°C or less.

[0064] <Curability> When measuring the temperature rise during curing, if the cured product of the curable artificial nail composition peeled off the black aluminum foil covering the Teflon® ring, the curability evaluation was marked as "×" and the product was deemed to have passed. If it did not peel off, the curability evaluation was marked as "○" and the product was deemed to have passed.

[0065] [Table 1]

[0066] Table 1 shows that the curable artificial nail compositions of Examples 1 to 8 according to the present invention contain (1) a urethane (meth)acrylate oligomer having a polycarbonate backbone with a mass average molecular weight of 30,000 or less and 1,000 or more, (2) a non-polymerizable organic polymer, (3) a (meth)acrylic monomer with a mass average molecular weight of less than 1,000, and (4) a polymerization initiator, thereby suppressing the temperature rise during curing to less than 23°C and demonstrating that there are no problems with curability. On the other hand, from Table 1, From Comparative Examples 1 and 2, it can be seen that (2) all curable artificial nail compositions that do not contain non-polymerizable organic polymers have curing temperatures exceeding 30°C, and when applied as gel nail (BASE gel) and cured, there is a risk that the user may feel heat, pain, or fear. <ii>From Comparative Example 3, it can be seen that (1) a curable artificial nail composition that does not contain a urethane (meth)acrylate oligomer having a polycarbonate skeleton with a mass-average molecular weight of 30,000 or less and 1,000 or more has a suppressed rise in temperature during curing, but has problems in terms of curability. <iii>From Comparative Example 4, it can be seen that (1) a curable artificial nail composition containing a large amount of a urethane (meth)acrylate oligomer (polyether urethane (meth)acrylate oligomer) that does not have a polycarbonate skeleton, and has a mass average molecular weight of 30,000 or less and 1,000 or more, exhibits a higher temperature rise during curing. <iv>From Comparative Example 5, it can be seen that (1) a curable artificial nail composition containing a small amount of a urethane (meth)acrylate oligomer (polyether urethane (meth)acrylate oligomer) that does not have a polycarbonate skeleton, and which is not a urethane (meth)acrylate oligomer with a mass average molecular weight of 30,000 or less and 1,000 or more, has problems in terms of curability. The curable artificial nail composition of the present invention has low curing heat (polymerization heat) when cured after application and excellent curability, making it extremely useful as a base gel, especially for each layer that makes up gel nails (top layer, color layer, and base layer).< / iv> < / iii> < / ii>

Claims

1. (1) A urethane (meth)acrylate oligomer having a polycarbonate backbone, with a mass-average molecular weight of 30,000 or less and 1,000 or more. (2) non-polymerizable organic polymer, (3) (meth)acrylic monomers with a mass-average molecular weight of less than 1,000, (4) Polymerization initiator, A curable artificial nail composition containing, The (2) non-polymerizable organic polymer is an organic polymer that does not have polymerizable groups in its molecule and does not participate in radical polymerization reactions, and includes polycarbonate polyurethane. The content of (1) above is 2% by mass or more and 85% by mass or less, based on the total amount of (1) to (4) of the curable artificial nail composition being 100% by mass. The content of (2) above is 1% by mass or more and 50% by mass or less, based on the total amount of (1) to (4) of the curable artificial nail composition being 100% by mass. The content of component (3) is 10% by mass or more and 55% by mass or less, based on the total amount of (1) to (4) of the curable artificial nail composition being 100% by mass, in the curable artificial nail composition.

2. The curable artificial nail composition according to claim 1, wherein the polymerization initiator is an α-hydroxyalkylphenone-based polymerization initiator.

3. The curable artificial nail composition according to claim 1 or 2, wherein the mass ratio of (1) to (2) is (1) / (2) = 2 / 98 to 60 / 40.

4. A curable artificial nail composition according to any one of claims 1 to 3, wherein the temperature rise during curing is 23°C or less.

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