Hardened artificial claw composition

Abstract

To provide a curable artificial nail composition that is practical in the adhesion of a cured coating to a substrate (adhesive force to a nail), the persistence of adhesion, curability, applicability and the appearance of the cured coating and also shows a low temperature rise during its curing.SOLUTION: A curable artificial nail composition contains the following A-C: A) a radical polymerizable component containing a compound having at least one radical polymerizable unsaturated double bond in each molecule, B: an acylphosphine oxide-based photopolymerization initiator, and C: an α-hydroxyalkylphenone-based photopolymerization initiator. When the total of A-C is 100 mass%, if the content of B is X mass% and the content of C is Y mass%, the following formula (1) holds: 1.79X+Y≥22.0 (where X is 30.0≥X>0 and Y is 30.0≥Y>0).SELECTED DRAWING: Figure 1

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] Recently, photocurable artificial nail compositions known as gel nails have been attracting attention as materials used for decorating or reinforcing nails. Gel nails are photocurable gel-type nail coating materials (photocurable artificial nail compositions), and are known to contain, for example, (meth)acrylate oligomers and (meth)acrylic monomers. 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.

[0004] Until now, 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 (adhesion to the nail), adhesion durability, curability, aesthetics of the cured coating film, etc. Meanwhile, it has been known that photocurable artificial nail compositions may cause users to feel hot or uncomfortable due to the temperature rise during curing caused by the curing heat (heat of polymerization) generated when the photocurable compound is photopolymerized to form a cured coating film, but detailed studies have not been conducted to date. Recently, there has been an increasing need for curable artificial nail compositions that have a low temperature rise during curing, even if they have properties such as adhesion of the cured coating film to the substrate (adhesion to the nail), durability of adhesion, curability, and the aesthetic appearance of the cured coating film, in order to prevent the user from feeling pain or fear due to heat.

[0005] For example, the following are known as curable artificial nail compositions such as gel nails. Patent Document 1 describes a base coat composition for auto nails that contains a urethane acrylate oligomer, a monomer component containing at least hydroxyethyl acrylamide and 2-hydroxyethyl methacrylate, a photopolymerization initiator, and a polymer component. This composition is rated for sensitivity to heat during curing on a three-point scale (high, medium, 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 radically polymerizable compound, a photopolymerization initiator, and a chain transfer agent. The composition is evaluated for the temperature rise during curing using a three-point scale: "perceptible," "slightly perceptible," and "perceptible as a heat pain," but the specific temperature is unknown. Patent Document 3 describes an artificial nail composition that contains component (a), which is a compound having at least one radically polymerizable unsaturated double bond in the molecule, and component (b), which is a photopolymerization initiator that is a mixture of an acylphosphine oxide-type photopolymerization initiator and an α-hydroxyalkylphenone-type photopolymerization initiator, and in which the content of component (b) is 0.05 to 4.00 parts by weight per 100 parts by weight of component (a). Patent Document 4 describes a photocurable composition for use as a top coat for nails or artificial nails, which comprises: component (A): a (meth)acrylic oligomer; component (B): a trifunctional (meth)acrylic monomer contained in an amount of 50 to 100 parts by mass per 100 parts by mass of component (A); and component (C): a photopolymerization initiator contained in an amount of 1 to 20 parts by mass per 100 parts by mass of component (A), and which contains 40 to 70% by mass of trimethylolpropane trimethacrylate relative to the total amount of component (B), and which has a transmittance of 10.0% or more at a wavelength of 400 nm in an 800 μm thick cured product. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2018-80129 [Patent Document 2] Japanese Patent Application Publication No. 2019-6689 [Patent Document 3] Patent No. 5465934 [Patent Document 4] International Publication No. 2016 / 072353 Summary of the Invention [Problem to be solved by the invention]

[0007] Patent Documents 1 and 2 only conduct a sensitivity evaluation of the temperature rise during curing of a curable artificial nail composition, but do not describe or suggest controlling the temperature rise during curing from the compositional aspect of the curable artificial nail composition. Patent Documents 3 and 4 do not describe or suggest controlling the temperature rise during curing from the viewpoint of the composition of the curable artificial nail composition.

[0008] The problem to be solved by the present invention is to provide a curable artificial nail composition that provides a cured coating film with practical adhesion to a substrate (adhesion to the nail), adhesion durability, curability, ease of application, and aesthetic appearance, and that also has a low temperature rise during curing. [Means for solving the problem]

[0009] As a result of extensive research into solving the above problems, the present inventors have found that the above problems can be solved by forming a curable artificial nail composition with a specific composition, and have thus completed the present invention. Specifically, the following applies: [1] A to C below; A: a radically polymerizable component containing a compound having at least one radically polymerizable unsaturated double bond in the molecule; B: acylphosphine oxide type photopolymerization initiator, C: α-hydroxyalkylphenone type photopolymerization initiator, Contains When the total of A to C is 100 mass%, the content of B is X mass% and the content of C is Y mass%, the following formula (1) is satisfied: 1.79X+Y≧22.0 (1) (In the formula, X is 30.0≧X>0, and Y is 30.0≧Y>0.) A curable artificial nail composition that satisfies the above requirements. [2] The curable artificial nail composition according to Item 1, wherein the radical polymerizable component is a compound having at least one (meth)acryloyl group in the molecule. [Effects of the Invention]

[0010] The curable artificial nail composition of the present invention exhibits practical properties of adhesion of the cured coating film to the substrate (adhesion to the nail), adhesion durability, curability, ease of application, and aesthetic appearance of the cured coating film, as well as the remarkable effect of a low temperature rise during curing. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a graph showing the relationship between the content of B: acylphosphine oxide-type photopolymerization initiator and the content of C: α-hydroxyalkylphenone-type photopolymerization initiator. DETAILED DESCRIPTION OF THE INVENTION

[0012] The curable artificial nail composition of the present invention will be described below. The curable artificial nail composition of the present invention comprises the following A to C: A: a radically polymerizable component containing a compound having at least one radically polymerizable unsaturated double bond in the molecule; B: acylphosphine oxide type photopolymerization initiator, C: α-hydroxyalkylphenone type photopolymerization initiator, Contains When the total of A to C is 100 mass%, the content of B is X mass% and the content of C is Y mass%, the following formula (1) is satisfied: 1.79X+Y≧22.0 (1) (In the formula, X is 30.0≧X>0, and Y is 30.0≧Y>0.) Meet the following.

[0013] The means for curing the curable artificial nail composition of the present invention is not particularly limited as long as it is capable of imparting energy that causes curing to the curable composition. Examples include irradiation with energy rays such as light (ultraviolet (UV) rays), electron beams, and heat. In particular, curing by irradiation with ultraviolet (UV) rays can be preferably used because it can be carried out relatively quickly and easily. The present inventors have found that highly reactive compounds, particularly highly photoreactive compounds, tend to generate heat when cured (polymerized) by irradiation with light, etc., resulting in a high temperature rise during curing. Therefore, it is possible to control the temperature rise during curing of the curable artificial nail composition by not using a relatively highly reactive compound such as an acryloyl group-containing polymerizable compound (acrylate compound), by reducing the content of the acryloyl group-containing polymerizable compound relative to 100% by mass of the total of all components of the curable artificial nail composition, or by reducing the content of the acryloyl group-containing polymerizable compound relative to 100% by mass of the total of the acryloyl group-containing polymerizable compound and the methacryloyl group-containing polymerizable compound in the curable artificial nail composition.

[0014] The mechanism by which the curable artificial nail composition of the present invention can reduce the temperature rise during curing is unknown, but the present inventors speculate as follows. The curable artificial nail composition of the present invention has a high blend ratio of B: acylphosphine oxide-type photopolymerization initiator and C: α-hydroxyalkylphenone-type photopolymerization initiator, which causes a rapid reaction when curing begins. Because the reaction is so rapid, the fluidity of the film of the curable artificial nail composition is suddenly lost. The loss of fluidity in the cured coating film of the curable artificial nail composition reduces the degree of freedom of the radicals that contribute to the reaction, resulting in lower reactivity and allowing a reduction in the temperature rise during curing. However, the present invention is not limited to this speculation.

[0015] [A: Radical polymerizable component] In the curable artificial nail composition of the present invention, A: the radically polymerizable component containing a compound having at least one radically polymerizable unsaturated double bond in the molecule is not particularly limited as long as it can initiate polymerization with B: the acylphosphine oxide-type photopolymerization initiator and C: the α-hydroxyalkylphenone-type photopolymerization initiator. The compound having at least one radically polymerizable unsaturated double bond in the molecule is a radically polymerizable compound having a functional group (also referred to as a polymerizable double bond) with a carbon-carbon double bond capable of radical polymerization. In the present invention, it is preferable to use a (meth)acryloyl group-containing polymerizable compound as the radically polymerizable compound. In addition, in the present invention, a radically polymerizable compound other than a (meth)acryloyl group-containing polymerizable compound may also be used as the radically polymerizable compound.

[0016] <(Meth)acryloyl Group-Containing Polymerizable Compound> The (meth)acryloyl group-containing polymerizable compound used as the radically polymerizable component of the curable artificial nail composition of the present invention includes one or more compounds selected from the group consisting of (meth)acrylate oligomers and (meth)acrylate monomers. As used herein, "(meth)acrylate oligomer" refers to acrylate oligomers and methacrylate oligomers, and "(meth)acrylate monomer" refers to acrylate monomers and methacrylate monomers.

[0017] ((Meth)acrylate oligomer) The (meth)acrylate oligomer is not particularly limited as long as it is an oligomer having one or more (meth)acryloyl groups. 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, the hardness of the cured coating film, and the like. 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. The weight-average molecular weight of the (meth)acrylate oligomer is not particularly limited. For example, it is 1,000 or more, preferably 2,000 or more, more preferably 3,000 or more, and for example, it is 100,000 or less, preferably 50,000 or less, 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.

[0018] The (meth)acrylate oligomer is not particularly limited, but examples thereof include: (i) (meth)acrylate oligomers having in their main skeleton (main chain) one or more bonds selected from the group consisting of urethane bonds, bonds resulting from a ring-opening reaction of an epoxy group, ester bonds, ether bonds, urea bonds, carbonate bonds, and amide bonds; and (ii) (meth)acrylate oligomers having in their main skeleton (main chain) molecular chains formed by polymerization of one or more monomers selected from the group consisting of styrene-based, (meth)acrylic, olefin-based, and diene-based monomers. Among these, the use of one or more oligomers selected from the group consisting of urethane (meth)acrylate oligomers ((meth)acrylate oligomers having a urethane bond in the main skeleton), epoxy (meth)acrylate oligomers having a molecular chain generated by a ring-opening reaction of an epoxy group, ester (meth)acrylate oligomers ((meth)acrylate oligomers having an ester bond in the main skeleton), and ether (meth)acrylate oligomers ((meth)acrylate oligomers having an ether bond in the main skeleton) is advantageous in terms of adhesion, etc. The (meth)acrylate oligomer may be either a commercially available product or a synthetic product. In the present invention, from the viewpoint of nail adhesion and durability of the curable artificial nail composition and / or its cured coating film, it is preferable that the curable artificial nail composition contains one or more types of urethane (meth)acrylate oligomer.

[0019] The urethane (meth)acrylate oligomer 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.

[0020] When a urethane (meth)acrylate oligomer is used in a curable artificial nail composition, a cured coating film having excellent stretchability, adhesion, and strength can be obtained. 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 skeletons selected from the group consisting of a polyether skeleton, a polycarbonate skeleton, a polyester skeleton, an acrylic skeleton, and a polyolefin skeleton, and among these, those having one or more skeletons of a polyether skeleton or a polycarbonate skeleton are preferred.

[0021] For example, a urethane (meth)acrylate oligomer having one or more types of polyether skeleton can be 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 polyether polyol such as polypropylene polyol with a polyisocyanate such as isophorone diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, or their isocyanurate or biuret derivatives, and then subjecting 10% or more of the total number of isocyanate groups in the urethane prepolymer to an addition reaction with the (meth)acrylic compound having a hydroxyl group.

[0022] The urethane (meth)acrylate oligomer may be a commercially available product, such as, but not limited to, one or more selected from the group consisting of AH-600, AT-600, UA-306H, and UF-8001G (manufactured by Kyoeisha Chemical Co., Ltd.), RUA-071, RUA-003VE, RUA-075, and RUA-048 (manufactured by Asia Chemical Industry Co., Ltd.), SUA TH1 and SUA 2 (manufactured by KSM Co., Ltd.), UV-3310B (manufactured by Mitsubishi Chemical Corporation), UN-9000PEP and UN-9200A (manufactured by Negami Chemical Industrial Co., Ltd.), AU-2040 (manufactured by Tokushiki Co., Ltd.), and KUA-PC2I (manufactured by KSM Co., Ltd.).

[0023] An epoxy (meth)acrylate oligomer having a molecular chain generated by a ring-opening reaction of an epoxy group can be synthesized, for example, by reacting a polyfunctional epoxy resin with a (meth)acrylate having a functional group reactive with an epoxy group, but the synthesis method is not limited to this. Examples of commercially available products include, but are not limited to, one or more selected from the group consisting of EBECRYL 1259, 605, 1606 (manufactured by Daicel-Cytec), EPOXY ESTER 3000A, 3000MK, 3002A(N), 3002M(N), 40EM (manufactured by Kyoeisha Chemical Co., Ltd.), etc.

[0024] An ester (meth)acrylate oligomer having an ester bond can be synthesized, for example, by adding a compound having a hydroxyl group and a (meth)acryloyl group in the molecule and / or (meth)acrylic acid or an acrylic compound having a carboxyl group to a carboxyl group and / or a hydroxyl group of an ester oligomer obtained by reacting a polyol with a polycarboxylic acid, but the synthesis method is not limited to this. Examples of commercially available products include, but are not limited to, one or more types selected from the group consisting of Aronix (registered trademark) M-6100, M-6200, M-6250, M-6500, M-7100, M-7300K, M-8030, M-8060, M-8100, M-8530, M-8560, and M-9050 (manufactured by Toagosei Co., Ltd.), and UV-3500BA, UV3520TL, UV-3200B, and UV-3000B (manufactured by Mitsubishi Chemical Corporation).

[0025] An ether (meth)acrylate oligomer having an ether bond can be synthesized, for example, by adding one or more members selected from the group consisting of a compound having a hydroxyl group and a (meth)acryloyl group in the molecule, (meth)acrylic acid, and a compound having a carboxyl group and a (meth)acryloyl group in the molecule to a hydroxyl group of an aliphatic polyether polyol or a hydroxyl group of an aromatic polyether polyol made from a raw material such as bisphenol, but the synthesis method is not limited to this. Examples of commercially available products include, but are not limited to, one or more selected from the group consisting of UV-6640B, UV-6100B, UV-3700B (manufactured by Mitsubishi Chemical Corporation), Light Acrylate (registered trademark) 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.), and EBECRYL (registered trademark) 3700 (manufactured by Daicel-Cytec Co., Ltd.).

[0026] ((Meth)acrylate Monomer) The (meth)acrylate monomer is not particularly limited as long as it is a monomer having one or more (meth)acryloyl groups. The number of (meth)acryloyl groups contained in one molecule is not particularly limited, but is 1 to 10, preferably 1 to 8, and more preferably 1 to 6, from the viewpoints of the curability of the curable artificial nail composition, the hardness of the cured coating film, and the like. In the present invention, it is preferable to use one or more (meth)acrylate monomers having one (meth)acryloyl group as the (meth)acrylate monomer. Alternatively, 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 may be used.

[0027] 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, and isopropyl (meth)acrylate. Esters of monohydric alcohols such as bornyl (meth)acrylate, phenyl (meth)acrylate, benzyl (meth)acrylate, and N-acryloyloxyethylhexahydrophthalimide with (meth)acrylic acid; acrylamide, hydroxyethyl acrylamide, dimethyl acrylamide, diethyl acrylamide, methacrylamide, N-methyl (meth)acrylamide, N-hydroxyethyl (meth)acrylamide, N-ethyl (meth)acrylamide, and N-methylol (meth)acrylamide. , N-Methoxymethyl(meth)acrylamide, N-Butoxymethyl(meth)acrylamide, 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-tert-butyl(meth)acrylamide, N,N-Diheptyl(meth)acrylamide, N,N-Dioctyl(meth)acrylamide (Meth)acryloyl group-containing amide compounds such as acrylamide, N,N-di-tert-octyl(meth)acrylamide, N,N-didodecyl(meth)acrylamide, N,N-dioctadecyl(meth)acrylamide, N,N-dimethylaminopropyl(meth)acrylamide, and N,N-dimethylaminoethyl(meth)acrylamide; hydroxyl group-containing (meth)acrylates such as 2-hydroxyethyl(meth)acrylate, 2-hydroxypropyl(meth)acrylate, and hydroxybutyl(meth)acrylate;Nitrogen-containing alkyl (meth)acrylates such as N,N-dimethylaminoethyl (meth)acrylate, N,N-diethylaminoethyl (meth)acrylate, and Nt-butylaminoethyl (meth)acrylate; glycidyl (meth)acrylate; 4-(meth)acryloyloxymethyl-2-cyclohexyl-1,3-dioxolane, adamantyl (meth)acrylate, (2-methyl-2-ethyl-1,3-dioxolan-4yl)methyl (meth)acrylate, cyclic trimethylolpropane formal (meth)acrylate, (2-isobutyl-2-methyl-1,3-dioxolan-4yl)methyl (meth)acrylate, (2-ethyl-2-methyl-1,3-dioxolan-4yl)methyl (meth)acrylate, and (1,4-dioxaspiro[4,5]decan-2yl)methyl (meth)acrylate. ) acrylate, tetrafurfuryl alcohol oligo(meth)acrylate, alkoxylated tetrahydrofurfuryl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, (3-ethyloxetan-3-yl)methyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate glycidyl ether, (meth)acryloylmorpholine, N-(meth)acryloyloxyethylhexahydrophthalimide, pentamethylpiperidyl (meth)acrylate, isocyanuric acid di(meth)acrylate, isocyanuric acid tri(meth)acrylate, triazine tri(meth)acrylate, N-(meth)acryloxysuccinimide, N-(meth)acryloxyphthalimide and other heterocycle-containing (meth)acrylates can be mentioned as one or more selected from the group consisting of;

[0028] Among these (meth)acrylate monomers having one (meth)acryloyl group, esters of monohydric alcohols and (meth)acrylic acid 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, and isobornyl (meth)acrylate, hydroxyethyl acrylamide, dimethyl acrylamide, diethyl acrylamide, N- Preferred is at least one selected from the group consisting of (meth)acryloyl group-containing amide compounds such as methyl(meth)acrylamide, N-hydroxyethyl(meth)acrylamide, N-ethyl(meth)acrylamide, N-methylol(meth)acrylamide, N,N-dimethylaminopropyl(meth)acrylamide, and N,N-dimethylaminoethyl(meth)acrylamide; hydroxyl group-containing (meth)acrylates such as 2-hydroxyethyl(meth)acrylate, 2-hydroxypropyl(meth)acrylate, and hydroxybutyl(meth)acrylate; and heterocycle-containing (meth)acrylates such as (meth)acryloylmorpholine and N-(meth)acryloyloxyethylhexahydrophthalimide.

[0029] Examples of the (meth)acrylate monomer having two or more (meth)acryloyl groups include 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 di(meth)acrylate, pentaerythritol di(meth)acrylate, ethoxylated bisphenol A di(meth)acrylate, propoxylated bisphenol A di(meth)acrylate (isopyridenediphenylbis(methacrylate) di(meth)acrylate monomers such as propoxylated ethoxylated bisphenol A di(meth)acrylate; tri(meth)acrylate monomers such as glycerin tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, ditrimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, and ε-caprolactone-modified tris(acryloxyethyl)isocyanurate; tetra(meth)acrylate monomers such as pentaerythritol tetra(meth)acrylate ) acrylate monomers; polypentaerythritol (meth)acrylates such as dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, tripentaerythritol (meth)acrylate, and tetrapentaerythritol (meth)acrylate; (meth)acrylate monomers having four or more (meth)acrylate groups such as ethoxylated isocyanuric acid triacrylate and ethoxylated pentaerythritol tetraacrylate; and the like.

[0030] Of these (meth)acrylate monomers having two or more (meth)acryloyl groups, it is preferable to use one or more selected from the group consisting of ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, polypropylene di(meth)acrylate, 1,3-butanediol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, propoxylated bisphenol A dimethacrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and the like.

[0031] <Radical polymerizable compounds other than (meth)acryloyl group-containing polymerizable compounds> The curable artificial nail composition of the present invention may use a radically polymerizable compound other than a (meth)acryloyl group-containing polymerizable compound as the radically polymerizable compound. Examples of radically polymerizable compounds other than a (meth)acryloyl group-containing polymerizable compound include vinyl group-containing compounds and allyl group-containing compounds. Specific examples include one or more 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, and allyl group-containing oligomers.

[0032] <Configuration of radically polymerizable component> According to the findings of the present inventors, the heat of polymerization generated during curing of a curable artificial nail composition is primarily due to the heat generated by the reaction of (meth)acryloyl groups with radicals. Therefore, when a component with a high degree of polymerization (high weight-average molecular weight), such as a (meth)acrylate oligomer, is used, the number of (meth)acryloyl groups per unit mass is reduced, and the number of reactive sites per unit mass is reduced, making it possible to reduce the heat of polymerization generated during curing (reducing the temperature rise during curing). On the other hand, when a polyfunctional (meth)acrylate is used, the number of (meth)acryloyl groups per unit mass is increased, which tends to increase the heat of polymerization generated. In the present invention, the temperature rise during curing can be reduced by increasing the degree of polymerization of the (meth)acrylate oligomer or the content of the (meth)acrylate oligomer.

[0033] The content of the radically polymerizable component relative to the entire curable artificial nail composition is, for example, 20.0 mass% or more, preferably 40.0 mass% or more, more preferably 50.0 mass% or more, and even more preferably 60.0 mass% or more, and for example, 88.2 mass% or less, preferably 80.0 mass% or less, more preferably 75.0 mass% or less, and even more preferably 70.0 mass% or less. The content of the (meth)acryloyl group-containing polymerizable compound in the radically polymerizable component is, for example, 20 to 100 mass %, and preferably 30 to 100 mass %. The content of the (meth)acrylate oligomer in the radical polymerizable component is, for example, 0 to 100% by mass, preferably 30 to 90% by mass, and more preferably 40 to 80% by mass. The content of the (meth)acrylate monomer in the radical polymerizable component is, for example, 0 to 100% by mass, preferably 10 to 70% by mass, and more preferably 20 to 60% by mass. In the present invention, it is preferable to use a mixture of the (meth)acrylate oligomer and the (meth)acrylate monomer.

[0034] In the curable artificial nail composition of the present invention, the content of the acryloyl group-containing polymerizable compound is low, for example, 30.0% by mass or less, and preferably 25% by mass or less, relative to 100% by mass of the total of all components of the curable composition, thereby making it possible to suppress the temperature rise during curing. In the curable artificial nail composition of the present invention, the content of the acryloyl group-containing polymerizable compound is low, for example, 40 mass % or less, and preferably 30 mass % or less, relative to 100 mass % in total of the acryloyl group-containing polymerizable compound and the methacryloyl group-containing polymerizable compound in the curable artificial nail composition, so that the temperature rise during curing can be kept low. The curable artificial nail composition of the present invention can keep the temperature rise during curing low by controlling the weight average molecular weight of the methacryloyl group-containing polymerizable compound in the curable artificial nail composition. By using these techniques, the temperature rise during curing of the curable artificial nail composition of the present invention can be more efficiently suppressed to a low level. The temperature rise during curing of the curable artificial nail composition of the present invention can be, for example, 23°C or lower, preferably 20°C or lower, and more preferably 15°C or lower.

[0035] [B: Acylphosphine oxide photoinitiator] Acylphosphine oxide-type photopolymerization initiators generate radicals when given energy by irradiation with light (e.g., ultraviolet light). Acylphosphine oxide-type photopolymerization initiators generate radicals when irradiated with ultraviolet light having a wavelength of 365 to 405 nm, which is emitted from a commonly used UV-LED light source. Therefore, even when curing is performed by irradiating light using various light sources, including a UV-LED light source, good curability can be imparted to the curable composition. Furthermore, when curing is performed by irradiating light using a UV-LED light source, yellowing of the cured coating film can be prevented.

[0036] Examples of acylphosphine oxide type photoinitiators include one or more selected from the group consisting of 2,4,6-trimethylbenzoyldiphenylphosphine oxide (Omnirad TPO), bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, benzoyldiphenylphosphine oxide, and the like. In particular, 2,4,6-trimethylbenzoyldiphenylphosphine oxide can also function as a skin conditioning agent and can therefore be preferably used in the present invention.

[0037] [C: α-Hydroxyalkylphenone type photoinitiator] The above α-hydroxyalkylphenone type photoinitiator generates radicals when energy is applied by irradiation with light (e.g., ultraviolet light). The α-hydroxyalkylphenone type photoinitiator has a relatively high molar absorption coefficient and low yellowing property.

[0038] Examples of α-hydroxyalkylphenone type photoinitiators include one or more selected from the group consisting of 1-hydroxy-cyclohexyl phenyl ketone (Omnirad 184), hydroxymethyl-1-phenyl-propan-1-one, 1-[4-(2-hydroxymethoxy)phenyl]-2-hydroxy-2-methylpropan-1-one, 2-hydroxy-1-[4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl]-2-methylpropan-1-one, 1-(4-(phenylthio)-2,2-(O-benzoyloxime))1-hydroxycyclohexyl phenyl ketone, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one, and the like.

[0039] <B: Content of acylphosphine oxide type photoinitiator and C: α-hydroxyalkylphenone type photoinitiator> The curable artificial nail composition of the present invention comprises A: a radically polymerizable component containing a compound having at least one radically polymerizable unsaturated double bond in the molecule, B: an acylphosphine oxide-type photopolymerization initiator, and C: an α-hydroxyalkylphenone-type photopolymerization initiator, and the content X (mass%) of B and the content Y (mass%) of C relative to the total of A to C being 100 mass% satisfy the following formula (1): 1.79X+Y≧22.0 (1) (In the formula, X is 30.0≧X>0, and Y is 30.0≧Y>0.) Preferably, the B content X (mass %) and the C content Y (mass %) satisfy the following formula (2). 1.79X+Y≧23.0 (2) (In the formula, X is 30.0≧X>0, and Y is 30.0≧Y>0.)

[0040] B: The content X (mass%) of the acylphosphine oxide photopolymerization initiator is more than 0 mass%, preferably 0.1 mass% or more, more preferably 0.5 mass% or more, and is 30.0 mass% or less, preferably 25.0 mass% or less, more preferably 20.0 mass% or less. C: The content Y (mass%) of the acylphosphine oxide type photopolymerization initiator is more than 0 mass%, preferably 0.1 mass% or more, more preferably 0.5 mass% or more, and is 30.0 mass% or less, preferably 28.0 mass% or less, more preferably 26.0 mass% or less.

[0041] In the present invention, by using the acylphosphine oxide-type photopolymerization initiator B and the α-hydroxyalkylphenone-type photopolymerization initiator C in a quantity ratio that satisfies the relationship represented by formula (1), the temperature rise during curing of the curable artificial nail composition can be kept within a range that is not uncomfortable for the user, for example, less than 23°C.

[0042] In the curable artificial nail composition of the present invention, the content of the polymerization initiator, relative to 100% by mass of the total of all components of the curable composition, is 22 / 1.79 (approximately 12.3)% by mass or more, preferably 23 / 1.79 (approximately 12.8)% by mass or more, more preferably 13.0% by mass or more, and is 60% by mass or less, preferably 50.0% by mass or less, more preferably 45% by mass or less.

[0043] <Other ingredients> Various additives can be blended into the curable artificial nail composition to the extent that they do not adversely affect the viscosity, usability, durability of the cured coating film, etc. Examples of such additives include one or more selected from the group consisting of various additives such as resins, polymerization initiators other than acylphosphine oxide-type photopolymerization initiators and other than α-hydroxyalkylphenone-type photopolymerization initiators, colorants, polyfunctional thiol compounds, polyol compounds, fragrances, silicone-based and fluorine-based antifoaming agents, silane coupling agents such as γ-glycidoxypropyltrimethoxysilane, polymerization accelerators such as tertiary amines, chain transfer agents, fillers, surface tension modifiers, polymerization inhibitors, solvents, flame retardants, antioxidants, ion adsorbents, stress reducers, preservatives, antibacterial agents, flexibility-imparting agents, waxes, halogen trapping agents, leveling agents, and wetting improvers.

[0044] The resin is not particularly limited as long as it 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, 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.

[0045] Examples of polymerization initiators other than acylphosphine oxide-type photopolymerization initiators and other than α-hydroxyalkylphenone-type photopolymerization initiators include those that generate radicals when given energy by irradiation with light (e.g., ultraviolet light) or heat, etc. Examples include one or more polymerization initiators selected from the group consisting of benzoin ether-based, benzil ketal-based, acid ester-based, α-aminoalkylphenone-based, benzophenone-based, thioxanthone-based, titanocene-based, quinone-based, peroxide-based, azo-based, and persulfate-based initiators.

[0046] Examples of polymerization initiators other than acylphosphine oxide type photopolymerization initiators and other than α-hydroxyalkylphenone type photopolymerization initiators include 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 chloride, and fluorothioxane. ton, 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 isoprenoid propyl 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 -oxide, cyclohexanone peroxide, dicumyl peroxide, di(3,5,5-trimethylhexanoyl) peroxide, dilauroyl peroxide, disuccinic acid peroxide, dibenzoyl peroxide, t-butyl peroxypivalate, t-butyl peroxybenzoate, t-hexyl peroxide parethoxylate, 2,5-dimethyl-2,5-di(2-ethylhexanoylperoxy)hexane, 1,1,3,3-tetramethylbutylperoxy-2-ethoxy 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-butyl Examples of the peroxycarbonate include one or more selected from the group consisting of di(4-t-butylcyclohexyl)peroxydicarbonate, 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.

[0047] 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.

[0048] 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 106, Red 2, Red 201, Red 202, Red 203, Red 204, Red 205, Red 206, Red 207, Red 208, Red 213, Red 214, Red 215, Red 218, Red 219, Red 220, Red 221, Red 223, Red 225, Red 226, Red 227, Red 228, Red 230-(1), Red 23 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 oxide, iron oxide, chromium oxide, manganese violet, carbon black, metal powder, metal flakes, metal oxide flakes, glass flakes, and the like.

[0049] The polyfunctional thiol compound is blended as a curability modifier, a crosslinking agent, and a viscosity modifier in the curable artificial nail composition. In addition, blending the polyfunctional thiol compound in the curable artificial nail composition can improve the wiping properties when wiping off and removing the cured coating film. Examples of polyfunctional thiol compounds include those obtained by reacting a hydroxyl group of a polyol compound such as trimethylolpropane, pentaerythritol, or dipentaerythritol with a compound having a thiol group or a group that reacts to become a thiol group. 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), and dipentaerythritol hexakis(3-mercaptopropionate) can be mentioned. When the polyfunctional thiol compound is contained in the curable artificial nail composition, it is preferably contained in an amount of 1.0 to 10.0 mass %.

[0050] 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. The alkyl polyol may be at least one 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.

[0051] Examples of polyester polyols include one or more selected from the group consisting of condensation polyester polyols, addition polymerization polyester polyols, and polycarbonate polyols. Condensation polyester polyols are obtained by a condensation reaction of 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, diol dimer acid, and polyethylene glycol with one or more organic polybasic acids selected from the group consisting of adipic acid, isophthalic acid, terephthalic acid, and sebacic acid, and preferably have a molecular weight of 100 to 100,000. Examples of addition polymerization polyester polyols include polycaprolactone, and preferably have a molecular weight of 100 to 100,000. Polycarbonate polyols are synthesized by direct phosgenation of polyols, transesterification with diphenyl carbonate, or the like, and preferably have a molecular weight of 100 to 100,000. Examples of polyether polyols include polyether polyols obtained by ring-opening polymerization of alkylene oxides.

[0052] The polymerization inhibitor may be, 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 contained in the curable artificial nail composition, it can be blended in an amount of 500 to 5000 ppm, preferably 1000 to 4500 ppm, based on the total amount of the curable artificial nail composition.

[0053] 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.

[0054] <Temperature Increase During Curing of Curable Artificial Nail Composition> In the present invention, the temperature rise during curing of the curable artificial nail composition can be determined by the method described in the examples below. The temperature rise during curing of the curable artificial nail composition of the present invention is preferably 23° C. or less, more preferably 20° C. or less, and even more preferably 15° C. or less. If the temperature rise during curing exceeds 23° C., the user may feel a strong heat sensation on the nail, which may cause discomfort. The lower limit of the temperature rise during curing is not particularly limited, but is, for example, 0° C. or higher, and preferably 5° C. or higher. If the temperature is lower than 0° C., the user may feel a strong cold on the nail, which may cause discomfort.

[0055] The viscosity of the curable artificial nail composition of the present invention at 25°C can be, for example, 0.1 Pa·s or more and 60.0 Pa·s or less. The viscosity is preferably 0.5 Pa·s or more, more preferably 0.7 Pa·s or more, and is preferably 50.0 Pa·s or less, more preferably 40.0 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.

[0056] <Uses of the curable artificial nail composition> The cured coating film of the curable artificial nail composition of the present invention has excellent adhesion to a substrate, maintains adhesion to the substrate for a long period of time, and has an appropriate hardness. The curable artificial nail composition of the present invention is a composition for coating the surface of a nail, like so-called common manicures or pedicures, and may be coated on the surface of the user's own nail, where necessary, by sanding or otherwise providing an uneven surface. It is particularly suitable for use as a gel nail, and can be used, for example, in any of a base coat layer that is applied directly to the user's nail, a color coat that is applied on the base coat layer, and a top coat layer that is further applied on top of that. When used as a color coat, the color can be adjusted to a variety of colors, such as solid colors, glitter, metallic luster, dark colors, and bright colors, using a colorant. When forming a cured coating film of the curable artificial nail composition of the present invention, the same equipment as that used when curing a radically polymerizable curable composition, such as general ultraviolet curing equipment or nail polish curing equipment, can be used.

[0057] Since the content of unpolymerized curable components in the cured coating film of the curable artificial nail composition of the present invention is reduced, the step of wiping off the unpolymerized curable components using a solvent such as ethanol, isopropanol, ethyl acetate, or acetone, particularly ethanol, can be omitted in some cases. Furthermore, when the curable artificial nail composition of the present invention is used in any layer, the cured coating film will not chip or peel off for a long period of time (e.g., at least two weeks after curing), and lifting from the underlying layer or the user's nail can be suppressed.

[0058] <Coating Nails with Curable Artificial Nail Composition> The nails to be coated with the curable composition of the present invention may be human fingernails or toenails, or may be the nails of animals such as dogs and cats. 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 used as any of a base coat layer (gel base; primer layer), an intermediate layer (color layer), and a top coat layer in a gel nail. In particular, because of its excellent adhesion to the substrate, it is suitable for use as a base coat layer (gel base; primer layer). After applying the curable artificial nail composition of the present invention, small decorations, powder, etc. can be attached to the coating surface of the curable artificial nail composition before curing to enhance the design.

[0059] Alternatively, a layer having the shape of a nail or the like can be prepared on one side of a sheet using the uncured 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 forming a layer on the surface of a sheet in advance using a curable artificial nail composition and then transferring the layer, 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 wash the applicator after use.

[0060] 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 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 varies 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 (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. As a light source for irradiating light, known ultraviolet light sources such as a mercury lamp, a metal halide lamp, an ultraviolet light emitting diode (UV-LED), an ultraviolet laser diode (UV-LD), etc. Among these, ultraviolet light emitting diodes (UV-LED) and ultraviolet laser diodes (UV-LD) are preferred from the viewpoints of small size, long life, high efficiency, and low cost. [Example]

[0061] 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."

[0062] [Examples 1 to 8, Comparative Examples 1 to 9] The components shown in Tables 1 and 2 were placed in a container in the amounts (parts by mass) shown in Tables 1 and 2, and the mixture was heated to 50°C and stirred with a dissolver. The mixture was degassed for 10 minutes under a pressure of 0.1 MPa while stirring, yielding a curable artificial nail composition. All of these steps were performed in the dark.

[0063] <Ingredients> The components in Tables 1 and 2 are as follows: (oligomer) PUA-1: Polyether polyurethane methacrylate (weight average molecular weight 29,000) obtained from hydroxyethyl methacrylate, isophorone diisocyanate, and polycarbonate diol (monomer) HBMA: 2-hydroxybutyl methacrylate IBXA: Isobornyl acrylate DMAA: Dimethylacrylamide (Polymerization initiator) TPO: 2,4,6-trimethylbenzoyldiphenylphosphine oxide HCPK: 1-hydroxycyclohexyl phenyl ketone

[0064] <Temperature rise during curing> The temperature rise during curing of the obtained curable artificial nail composition was measured as follows. The results are shown in Tables 1 and 2. (Measurement start temperature and curing heat measurement) The temperature at the start of measurement was measured using a temperature measuring device during curing attached to a cure shrinkage meter (trade name Custron, manufactured by Acroedge Co., Ltd.), and the temperature during curing was measured, with the maximum temperature being taken as the curing heat. The samples used in measuring the 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 punched in a Teflon (registered trademark) plate to prepare a Teflon ring. The prepared Teflon 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 1.0±0.1 mm. The Teflon 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 Teflon ring, and the heat of curing generated during curing was measured.

[0065] (Calculation of temperature rise during curing) Using the obtained curing heat, the following formula (A): Temperature rise during curing (℃) = Heat of curing (℃) - Measurement start temperature (℃) The temperature rise during curing was calculated using the following formula.

[0066] [Table 1]

[0067] [Table 2]

[0068] The curable artificial nail compositions of Examples 1 to 8 all had practical adhesion to the substrate (adhesion to the nail), adhesion durability, curability, ease of application, and aesthetic appearance of the cured coating film, and could be used as gel nails without any problems. From Tables 1 and 2, when the total of A: radical polymerizable component, B: acylphosphine oxide type photopolymerization initiator, and C: α-hydroxyalkylphenone type photopolymerization initiator is 100 mass %, the content of B is X mass % and the content of C is Y mass %, the curable artificial nail composition satisfies the formula (1); 1.79X+Y≧22.0 (1) (In the formula, X is 30.0≧X>0, and Y is 30.0≧Y>0.) When the above condition is satisfied, the temperature rise during curing can be kept low. Specifically, it is possible to keep the temperature rise during curing to 23°C or less.

Claims

1. Below A to C: A: a radically polymerizable component containing a compound having at least one radically polymerizable unsaturated double bond in the molecule; B: acylphosphine oxide type photopolymerization initiator, C: an α-hydroxyalkylphenone type photopolymerization initiator, Contains The A contains a hydroxyl group-containing (meth)acrylate having one (meth)acryloyl group, When the total of A to C is 100 mass%, the content of B is X mass%, and the content of C is Y mass%, the following formula (1): 1.79X+Y≧23.0...(1) (In the formula, X is 30.0≧X>0, and Y is 30.0≧Y>0.) A curable artificial nail composition that satisfies the above requirements.

2. The curable artificial nail composition according to claim 1, wherein the temperature rise during curing when the curable artificial nail composition has a diameter of 1.0 mm and a film thickness before curing of 1.0±0.1 mm is 5°C or higher and 23°C or lower.

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