JP7779500B2 - Curable artificial nail composition - Google Patents

Description

The present invention relates to a curable artificial nail composition.

Nail art, which involves decorating natural fingernails or toenails or gluing artificial nails onto them, is becoming increasingly popular. Furthermore, artificial nails are often 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.

Recently, curable artificial nail compositions known as gel nails have been attracting attention as materials used to decorate or reinforce nails. Gel nails are curable gel-like nail coating materials (curable 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 exposure to ultraviolet light, forming a cross-linked polymer coating through a radical polymerization reaction, which is said to create a tough coating that is resistant to peeling from the nail.

Gel nails generally include a base coat that is applied directly to the user's nail, a color coat that is applied over the base coat, and a top coat that is applied over the color coat.
Of these, the most important quality of the top coat is glossiness, and in particular, the top coat after the uncured components have been wiped off must have high glossiness and excellent luster.

Patent Document 1 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); the composition contains 40 to 70% by mass of trimethylolpropane trimethacrylate relative to the total amount of component (B); and the composition has a transmittance of 10.0% or more at a wavelength of 400 nm in an 800 μm thick cured product.
This photocurable composition for top coating of nails or artificial nails was applied to a test piece to a thickness of 100 μm, then cured by irradiating it with a nail LED lamp having a wavelength of 400 to 410 nm for 10 seconds, the uncured components were wiped off, and the gloss was visually confirmed. The evaluation of "gloss after surface treatment" was "Good: glossy." However, there is no mention of the curability or glossiness when irradiated with UV light having a wavelength of approximately 365 nm.

Patent Document 2 describes a photocurable artificial nail composition containing acryloylmorpholine, a urethane (meth)acrylate oligomer, and a polyfunctional radically polymerizable unsaturated group-containing compound other than the urethane (meth)acrylate oligomer.
This photocurable artificial nail composition is prepared by forming a coating film of a certain thickness on a plate, curing it by irradiating it with LED-UV light having a wavelength of 405 nm for 20 seconds, wiping off any uncured components from the cured coating film, and measuring the gloss value with a gloss checker, which is said to be 136 to 145. However, there is no mention of the curability or glossiness when irradiated with UV light having a wavelength of approximately 365 nm.

International Publication No. 2016/072353 JP 2017-66042 A

Currently, methods used to harden gel nails include irradiation with LED light (wavelength 385 to 415 nm; peak wavelength approximately 405 nm) and irradiation with UV light (wavelength 350 to 400 nm; peak wavelength approximately 365 nm, approximately 370 nm, approximately 375 nm, or approximately 380 nm).
Conventional curable artificial nail compositions have a specific wavelength at which they cure, and it has been necessary to select a light appropriate for the wavelength at which they cure. When irradiated with either UV light or LED light, a top coat cured film with excellent curability and high gloss can be formed, but when irradiated with the other, the curability and gloss may be insufficient. For this reason, curable artificial nail compositions, particularly those used as top coats for gel nails, are required to form a top coat cured film with excellent curability and high gloss, regardless of whether they are irradiated with UV light or LED light.
The problem to be solved by the present invention is to provide a curable artificial nail composition that forms a cured coating film that has excellent curability and a high gloss when irradiated with either an LED light or a UV light.

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:
[Item 1] Component (A): at least a compound of formula (1):
-OCONH-R ¹ -NHCOO-R ² - (1)
(In the formula, ^R1 is a divalent organic group containing an alicyclic structure, and ^R2 is an aliphatic hydrocarbon group.)
A urethane (meth)acrylate oligomer having a repeating unit represented by the formula:
Component (B): At least a compound of formula (2):
[ _CH2 = ^CHR3- COO- ^R4 - _CH2 -CH(OH) _-CH2 -O-] ^pR5 (OH)q (2)
(In the formula, ^R3 is hydrogen or a methyl group, ^R4 is a single bond or a group represented by ^-R6 -O- ( ^R6 is a divalent organic group), ^R5 is a divalent or higher aromatic hydrocarbon group, p is an integer of 1 or greater, and q is an integer of 0 or greater.)
An acrylate compound having a structure represented by the formula:
Component (C): a (meth)acrylate compound other than components (A) and (B),
Component (D): polymerization initiator,
1. A curable artificial nail composition comprising:
[Item 2] The curable artificial nail composition according to Item 1, wherein the content of component (B) is 5 parts by mass or more and 40 parts by mass or less per 100 parts by mass of the total of component (A) and component (C).

The present invention has the remarkable effect of producing a curable artificial nail composition that forms a cured coating film with excellent curability and high gloss, whether irradiated with LED light or UV light.

The curable artificial nail composition of the present invention will be described below.
The curable artificial nail composition of the present invention comprises:
Component (A): At least a compound of formula (1):
-OCONH-R ¹ -NHCOO-R ² - (1)
(In the formula, ^R1 is a divalent organic group containing an alicyclic structure, and ^R2 is an aliphatic hydrocarbon group.)
A urethane (meth)acrylate oligomer having a repeating unit represented by the formula:
Component (B): At least a compound of formula (2):
[ _CH2 = ^CHR3- COO- ^R4 - _CH2 -CH(OH) _-CH2 -O-] ^pR5 (OH)q (2)
(In the formula, ^R3 is hydrogen or a methyl group, ^R4 is a single bond or a group represented by ^-R6 -O- ( ^R6 is a divalent organic group), ^R5 is a divalent or higher aromatic hydrocarbon group, p is an integer of 1 or greater, and q is an integer of 0 or greater.)
An acrylate compound having a structure represented by the formula:
Component (C): a (meth)acrylate compound other than components (A) and (B),
Component (D): polymerization initiator,
Includes.
In this specification, "(meth)acrylate" means both "acrylate" and "methacrylate".

When the curable artificial nail composition of the present invention is irradiated with either an LED light or a UV light, if a top coat for a gel nail is cured by UV, uncured components remain on the surface due to inhibition by oxygen. When this is wiped off with a solvent, if the curability is poor, scratches will occur, and as a result, the gloss of the coating film will often deteriorate.
The curable artificial nail composition of the present invention uses a combination of component (A), which has good UV curability, and component (B), which has high UV curability and forms a coating film with high hardness and a high refractive index after curing, to form a top coat cured coating film with excellent curability, high coating hardness, and high gloss, regardless of whether the composition is irradiated with LED light having a wavelength of approximately 405 nm or UV light having a wavelength of approximately 365 nm.
The inventors speculate that this reduces the occurrence of scratches when wiping off the uncured components with a solvent, and furthermore makes it easier to wipe off the uncured components, resulting in a high gloss appearance, but the present invention is not limited to this speculation.

[Component (A)]
The component (A) is at least a compound represented by the formula (1):
-OCONH-R ¹ -NHCOO-R ² - (1)
(In the formula, ^R1 is a divalent organic group containing an alicyclic structure, and ^R2 is an aliphatic hydrocarbon group.)
It is a urethane (meth)acrylate oligomer having a repeating unit represented by the following formula:
The component (A) can be obtained, for example, by reacting at least a polyurethane oligomer obtained by reacting an alicyclic polyisocyanate with an alkane polyol with a hydroxyalkyl (meth)acrylate compound or an isocyanate group-containing (meth)acrylate compound.

There are no particular limitations on the alicyclic diisocyanate, but specifically, those with 7 to 30 carbon atoms are preferred. For example, isophorone diisocyanate (IPDI), 1,3-cyclopentane diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, 1,4-bis(isocyanatemethyl)cyclohexane, 1,3-bis(isocyanatemethyl)cyclohexane, 4,4'-dicyclohexylmethane diisocyanate, hydrogenated xylylene diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated tetramethylxylene diisocyanate, bis(2-isocyanatoethyl)-4-cyclohexene-1,2-dicarboxylate, 2,5-norbornane diisocyanate, 2,6-norbornane diisocyanate, and the like. Of these, one or more selected from the group consisting of isophorone diisocyanate, 1,3-cyclopentane diisocyanate, 1,4-cyclohexane diisocyanate, hydrogenated xylylene diisocyanate, hydrogenated tolylene diisocyanate, and hydrogenated diphenylmethane diisocyanate are preferred.

The alkane polyol is not particularly limited as long as it is a compound in which two or more hydrogen atoms of an alkane are substituted with hydroxyl groups. The molecular weight is, for example, less than 500, preferably 50 to 300. Examples include one or more selected from the group consisting of ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,3-butanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 2-methyl-1,3-propanediol, 3,3,5-trimethylpentanediol, 2,4-diethyl-1,5-pentanediol, and 1,12-octadecanediol. Of these, one or more selected from the group consisting of 1,3-propanediol, 1,4-butanediol, 1,3-butanediol, and 1,6-hexanediol are preferred.

The polyurethane oligomer is obtained by reacting an alicyclic polyisocyanate with an alkane polyol in a molar ratio of (alicyclic polyisocyanate)/(alkane polyol) ranging from 1/1.8 to 1.8/1, for example. The number of repeating units in the polyurethane oligomer is, for example, 3 or more, preferably 6 or more, and for example, 30 or less, preferably 15 or less.
The polyurethane oligomer is terminated with an isocyanate group or a hydroxyl group. When the polyurethane oligomer terminates with an isocyanate group, component (A) is obtained by reacting it with a hydroxyalkyl (meth)acrylate compound. When the polyurethane oligomer terminates with a hydroxyl group, component (A) is obtained by reacting it with an isocyanate group-containing (meth)acrylate compound.

The hydroxyalkyl (meth)acrylate compound may be at least one selected from the group consisting of hydroxyalkyl (meth)acrylates, polyol (meth)acrylates, and alkylene oxide-added polyol (meth)acrylates. For example, hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 1-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 1-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 1-hydroxybutyl (meth)acrylate, and hydroxyphenoxypropyl (meth)acrylate; trimethylolpropane (meth)acrylate, trimethylolpropane di(meth)acrylate, pentaerythritol (meth)acrylate, pentaerythritol di(meth)acrylate, dipentaerythritol (meth)acrylate, dipentaerythritol di(meth)acrylate, and ditrimethylolpropane (meth)acrylate; [0033] Examples of the alkylene oxide-added polyol (meth)acrylate include one or more selected from the group consisting of polyol (meth)acrylates such as ditrimethylolpropane di(meth)acrylate; (meth)acrylates having an alkylene glycol chain 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; and alkylene oxide-added polyol (meth)acrylates such as alkylene oxide-added trimethylolpropane di(meth)acrylate, alkylene oxide-added pentaerythritol tri(meth)acrylate, and alkylene oxide-added dipentaerythritol penta(meth)acrylate.
Of these, hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate are preferred.

Examples of isocyanate group-containing (meth)acrylate compounds include one or more compounds selected from the group consisting of 2-isocyanatoethyl (meth)acrylate, 3-isocyanatopropyl (meth)acrylate, 2-isocyanato-1-methylethyl (meth)acrylate, 2-isocyanato-1,1-dimethylethyl (meth)acrylate, 4-isocyanatocyclohexyl (meth)acrylate, 2-(2-isocyanatoethoxy)ethyl (meth)acrylate, 1,1-bis((meth)acryloyloxymethyl)ethyl isocyanate, 2-(2-(meth)acryloyloxyethyloxy)ethyl isocyanate, and derivatives thereof. Derivatives include, for example, compounds having an isocyanate group masked with a blocking agent and at least one (meth)acryloyl group, such as 2-[(3,5-dimethylpyrazolyl)carbonylamino]ethyl methacrylate and 2-(0-[1'-methylpropylideneamino]carboxyamino)ethyl methacrylate. Commercially available products include, for example, one or more selected from the group consisting of Karenz AOI, Karenz MOI, AOI-VM, Karenz MOI-EG, Karenz BEI, Karenz MOI-BP, and Karenz MOI-BM (all registered trademarks manufactured by Showa Denko KK).

In the present invention, component (A) is preferably a urethane (meth)acrylate oligomer obtained by reacting an isocyanate-terminated polyurethane oligomer having a weight average molecular weight of 10,000 or less, preferably 6,000 or less, obtained by reacting one or more alicyclic polyisocyanates selected from the group consisting of isophorone diisocyanate (IPDI), 1,4-cyclohexane diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, hydrogenated xylylene diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated diphenylmethane diisocyanate, and hydrogenated tetramethylxylene diisocyanate with one or more alkane polyols selected from the group consisting of 1,3-propanediol, 1,4-butanediol, 1,3-butanediol, and 1,6-hexanediol, with a hydroxyalkyl (meth)acrylate compound.
More preferred is a polyurethane (meth)acrylate oligomer (cosmetic ingredient name: bisHEA (poly(1,4-butanediol)-9/IPDI) copolymer) obtained by reacting a polyurethane oligomer having an average of nine repeating units obtained from 1,4-butanediol and isophorone diisocyanate and having an isocyanate group at its terminal with two moles of hydroxyethyl acrylate, or a polyurethane (meth)acrylate oligomer (cosmetic ingredient name: bisHEMA (poly(1,4-butanediol)-9/IPDI) copolymer) obtained by reacting a polyurethane oligomer having an average of nine repeating units obtained from 1,4-butanediol and isophorone diisocyanate and having an isocyanate group at its terminal with two moles of hydroxyethyl methacrylate.

The content of component (A) in the curable artificial nail composition of the present invention is not particularly limited. For example, the content is 50% by mass or more, preferably 60% by mass or more, and for example, 90% by mass or less, preferably 80% by mass or less, where the total amount of components (A) to (D) in the curable artificial nail composition is 100% by mass. If the content of component (A) is less than 50% by mass, the viscosity of the curable artificial nail composition may be too low, causing problems with application, etc., and the gloss of the cured coating film may be reduced. If the content exceeds 90% by mass, the viscosity of the curable artificial nail composition may be too high, causing problems with application, etc.

[(B) Component]
The component (B) is at least a compound represented by the formula (2):
[ _CH2 = ^CHR3- COO- ^R4 - _CH2 -CH(OH) _-CH2 -O-] ^pR5 (OH)q (2)
(In the formula, ^R3 is hydrogen or a methyl group, ^R4 is a single bond or a group represented by ^-R6 -O- ( ^R6 is a divalent organic group), ^R5 is a divalent or higher aromatic hydrocarbon group, p is an integer of 1 or greater, and q is an integer of 0 or greater.)
The component (B) is an acrylate compound having a structure represented by the formula: Component (B) has the effect of imparting high hardness to the cured coating film. Component (B) can be obtained, for example, by reacting at least a polyphenol compound with a (meth)acrylate compound having an epoxy group. Component (B) can also be obtained by reacting at least an aromatic polyepoxy compound with a hydroxyalkyl (meth)acrylate compound.

Examples of polyphenol compounds include bisphenol A (bis(4-hydroxyphenyl)-2,2-propane), bisphenol F (bis(4-hydroxyphenyl)methane), (2,2-bis(4-hydroxycyclohexyl)propane, bis(4-hydroxycyclohexyl)methane, 4,4'-dihydroxydiphenyl ketone, bis(4-hydroxyphenyl)-1,1-ethane, bis(4-hydroxyphenyl)-1,1-isobutane, bis(4-hydroxy-3-t-butyl-phenyl)-2, Examples include one or more selected from the group consisting of 2-propane, bis(2-hydroxynaphthyl)methane, tetra(4-hydroxyphenyl)-1,1,2,2-ethane, 4,4'-dihydroxydiphenyl sulfone, 4,4'-dihydroxydiphenyl ether, 1,4-bis(4-hydroxyphenoxy)benzene, 1,3-bis(4-hydroxyphenoxy)benzene, 4,4'-dihydroxydiphenyl sulfide, 4,4'-dihydroxybiphenyl, phenol novolac, cresol novolac, and the like.
The aromatic polyepoxy compound may be, for example, one or more compounds selected from the group consisting of glycidyl ether compounds of the above-mentioned polyphenol compounds.

Examples of the (meth)acrylate compound having an epoxy group include one or more compounds selected from the group consisting of glycidyl group-containing (meth)acrylate compounds such as glycidyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate glycidyl ether, and epoxycyclohexylmethyl (meth)acrylate; and mono(meth)acrylate products of diglycidyl ether compounds such as dihydroxybenzene diglycidyl ether, dihydroxynaphthalene diglycidyl ether, biphenol diglycidyl ether, and bisphenol diglycidyl ether.
Examples of the hydroxyalkyl (meth)acrylate compound include one or more compounds selected from the group consisting of the hydroxyalkyl (meth)acrylate compounds described above in [Component (A)].

In the present invention, the component (B) is preferably a compound obtained by reacting a bisphenol compound with a glycidyl group-containing (meth)acrylate compound, more preferably a compound obtained by reacting bisphenol A with a glycidyl group-containing (meth)acrylate compound, and is more preferably a compound represented by the following formula (3) obtained by reacting bisphenol A with glycidyl methacrylate:
...(3)
Propoxylated bisphenol A dimethacrylate (bisphenol A diglycidyl methacrylate; Bis-GMA) represented by the following formula is more preferred.

The content of component (B) in the curable artificial nail composition of the present invention is not particularly limited. For example, the content is 5% by mass or more, preferably 10% by mass or more, and for example, 50% by mass or less, preferably 30% by mass or less, where the total amount of components (A) to (D) in the curable artificial nail composition is 100% by mass. If the content of component (B) is less than 5% by mass, the coating film strength of the curable artificial nail composition may be low and the composition may be prone to scratches. If the content exceeds 50% by mass, the flexibility of the cured coating film may be reduced and the composition may be prone to cracking or chipping.
Furthermore, the content of the component (B) is preferably 5 parts by mass or more and 40 parts by mass or less per 100 parts by mass of the total of the components (A) and (C).

[(C) Component]
The component (C) is a (meth)acrylate compound other than the components (A) and (B).
Examples of such (meth)acrylate compounds include:
i: a (meth)acrylate monomer having one or more (meth)acryloyl groups;
ii: a (meth)acrylate oligomer having one or more (meth)acryloyl groups,
One or more selected from the group consisting of:
Here, 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, 30,000 or less, more preferably 20,000 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 a low viscosity.

<(i) (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 coating film, and the like.
In the present invention, it is preferable to use, as the (meth)acrylate monomer, one or more types selected from (meth)acrylate monomers having one (meth)acryloyl group. It is also preferable to use a mixture of one or more types selected from (meth)acrylate monomers having one (meth)acryloyl group and one or more types selected from (meth)acrylate monomers having two or more (meth)acryloyl groups.

Examples of (meth)acrylate monomers having one (meth)acryloyl group include monohydric alcohols and (meth)acrylates 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, phenyl (meth)acrylate, and benzyl (meth)acrylate. esters with acrylic acid; the hydroxyalkyl(meth)acrylate compounds described above in [Component (A)]; (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, etc. p) Acryloyl group-containing amide compounds; 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, cyclic trimethylolpropane formal (meth)acrylate, (1,4-dioxaspiro[4,5]decan-2yl)methyl (meth)acrylate, tetrafurfuryl alcohol oligo(meth)acrylate, alkoxylated tetrahydrofurfuryl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate Examples include one or more selected from the group consisting of heterocycle-containing (meth)acrylates such as methyl (3-ethyloxetan-3-yl)methyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate glycidyl ether, glycidyl (meth)acrylate, (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, and N-(meth)acryloxyphthalimide.

Of these (meth)acrylate monomers having one (meth)acryloyl group, one or more selected from the group consisting of 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; hydroxyalkyl (meth)acrylates, such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and hydroxybutyl (meth)acrylate; and heterocyclic ring-containing (meth)acrylates, such as (meth)acryloylmorpholine, are preferred.

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, pentaerythritol 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 (isopyridenediphenylbis(oxyhydroxypropyl methacrylate), etc.), and propoxylated ethoxylated bisphenol A di(meth)acrylate. di(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; dipentaerythritol Examples include one or more selected from the group consisting of polypentaerythritol (meth)acrylates such as penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, tripentaerythritol (meth)acrylate, and tetrapentaerythritol (meth)acrylate, and (meth)acrylate monomers having five or more (meth)acrylate groups such as ethoxylated isocyanuric acid triacrylate and ethoxylated pentaerythritol tetraacrylate.

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, 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.

<(ii) (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 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, 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 weight-average molecular weight within this range, it is possible to improve the durability of the cured product while maintaining low viscosity.

The (meth)acrylate oligomer is not particularly limited, but examples thereof include:
a (meth)acrylate oligomer having, in its main skeleton (main chain), one or more bonds selected from the group consisting of a urethane bond, an ester bond, an ether bond, a urea bond, a carbonate bond, and an amide bond;
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, olefin-based, and diene-based monomers;
and the like.
The (meth)acrylate oligomer may be either a commercially available product or a synthetic product.

Examples of (meth)acrylate oligomers having one or more bonds selected from the group consisting of urethane bonds, ester bonds, ether bonds, urea bonds, carbonate bonds, and amide bonds in the main skeleton (main chain) include one or more bonds selected from the group consisting of urethane (meth)acrylate oligomers ((meth)acrylate oligomers having urethane bonds in the main skeleton), carbonate (meth)acrylate oligomers ((meth)acrylate oligomers having carbonate bonds in the main skeleton), ester (meth)acrylate oligomers ((meth)acrylate oligomers having ester bonds in the main skeleton), and ether (meth)acrylate oligomers ((meth)acrylate oligomers having ether bonds in the main skeleton).

The urethane (meth)acrylate oligomer 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 the molecule (e.g., hydroxyalkyl (meth)acrylate, (meth)acrylic acid, etc.), but the synthesis method is not limited to this.
The polyol may have, for example, one or more types selected from the group consisting of a polyether skeleton, a polycarbonate skeleton, and an ester skeleton.

Examples of urethane (meth)acrylate oligomers include those obtained by addition reaction of at least a portion of the isocyanate groups in an isocyanate group-containing polyether urethane prepolymer with a (meth)acrylic compound having a hydroxyl group. The isocyanate group-containing polyether urethane prepolymer is, for example, obtained by reacting a polyol compound having an alkylene group having 3 or more carbon atoms with a polyisocyanate, and has a weight average molecular weight of 400 to 30,000.
The polyol compound is preferably polypropylene polyol. The polyisocyanate may be at least one selected from the group consisting of non-aromatic polyisocyanates such as isophorone diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, and their isocyanurates and biuret derivatives.

The ester (meth)acrylate oligomer 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 the carboxyl group and/or 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).

The ether (meth)acrylate oligomer 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 groups of an aliphatic polyether polyol or an aromatic polyether polyol made from a bisphenol or the like, but is not limited to this method.
Examples of commercially available products include 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.), EBECRYL (registered trademark) 3700 (manufactured by Daicel-Cytec Co., Ltd.), and one or more types selected from the group consisting of these, but are not limited thereto.

Examples of (meth)acrylate oligomers 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 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 polyisocyanate, followed by reaction with a (meth)acrylate compound having a functional group reactive with a hydroxyl group or an isocyanate group.
Among these, urethane (meth)acrylate oligomers obtained using one or more polyol components selected from the group consisting of acrylic polyols, polyolefin polyols, butadiene polyols, etc. are preferred.

Of these, component (C) is preferably "i: (meth)acrylate monomer having one or more (meth)acryloyl groups," more preferably an ester of a monohydric alicyclic alcohol with (meth)acrylic acid, such as cyclohexyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, or isobornyl (meth)acrylate, or a hydroxyalkyl (meth)acrylate, such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, or hydroxybutyl (meth)acrylate, and even more preferably isobornyl (meth)acrylate or hydroxyethyl (meth)acrylate.

The content of component (C) in the curable artificial nail composition of the present invention is not particularly limited. For example, it is 5% by mass or more, preferably 10% by mass or more, and for example, 50% by mass or less, preferably 40% by mass or less, where the total amount of components (A) to (D) in the curable artificial nail composition is 100% by mass. If the content of component (C) is less than 5% by mass, the viscosity of the curable artificial nail composition may become too high, causing problems with application and handling, and there is a risk of reduced adhesion. If the content exceeds 50% by mass, the viscosity of the curable artificial nail composition may become too low, causing problems with application and handling, etc.

[(D) Component]
The component (D) is a polymerization initiator. The polymerization initiator generates radicals when energy is imparted to it by irradiation with light (e.g., ultraviolet light, visible light, etc.) or heat. Examples of the polymerization initiator include one or more polymerization initiators selected from the group consisting of acylphosphine oxides, α-hydroxyalkylphenones, benzoin ethers, benzil ketals, acid esters, α-aminoalkylphenones, benzophenones, thioxanthones, titanocenes, quinones, peroxides, azo compounds, and persulfates.
For example, when a photopolymerization initiator is used, good curability can be imparted to the curable artificial nail composition even when the composition is irradiated with light using various light sources including a UV-LED light source.

For example, acylphosphine oxide polymerization initiators generate radicals when irradiated with ultraviolet light having a wavelength of 365 to 405 nm, which is emitted from commonly used UV-LED light sources. Therefore, even when the composition is cured by irradiation with light from various light sources, including UV-LED light sources, the curable artificial nail composition can be imparted with good curability. Furthermore, when the composition is cured by irradiation with light from a UV-LED light source, yellowing of the cured coating film can be prevented.
Examples of the acylphosphine oxide polymerization initiator 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.

Examples of polymerization initiators other than acylphosphine oxide polymerization initiators include 1-hydroxycyclohexyl phenyl ketone, 1-(4-(phenylthio)-2,2-(O-benzoyloxime))1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methylpropionyl)-benzyl]-phenyl}-2-methylpropan-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, 3-[3,4-dimethyl-9-oxo-9H-thioxanthone-2-yl-oxy]-2-hydroxypropyl-N,N,N-trimethylammonium chloride, fluorothioxanthone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butane- 1-one, 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one, oligo(2-hydroxy-2-methyl-1-(4-(1-methylvinyl)phenyl)propanone), 4-benzoyl-4'-methyl-diphenyl sulfide, 1,2-octanedione, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1,2,2-dimethoxy-1,2-diphenylethan-1-one, 2-hydroxy-1-{4-[ 4-(2-hydroxy-2-methylpropionyl)-benzyl]phenyl}-2-methylpropane, isophthalphenone, methyl phenylglyoxylate, butylanthraquinone, ethylanthraquinone, phenanthrenequinone, camphorquinone, benzophenone, 4-phenylbenzophenone, benzoylbenzoic acid, hydroxybenzophenone, 4,4'-bis(diethylamino)benzophenone, benzoin, benzoin ethyl ether, benzoin isopropyl ether, benzoin butyl ether, benzoin isobutyl ether, benzyl dimethyl ketone 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 bis(1-cyclohexanecarbonitrile), 2,2'-azobis(2-methylpropionitrile), 2,2'-azobis(2-cyclopropylpropionitrile), 2,2'-azobis(methyl isobutyrate), t-butyl hydroperoxide, cumene hydroperoxide, diacetyl peroxide, didecanoyl peroxide, di-t-butyl peroxide, methyl ethyl ketone peroxide, cyclohexanone peroxide, dicumyl peroxide, di(3,5,5-trimethylhexanoyl) peroxide, dilauroyl peroxide, di Benzoyl peroxide, t-butyl peroxypivalate, t-butyl peroxybenzoate, 2,5-dimethyl-2,5-di(2-ethylhexanoylperoxy)hexane, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, t-butylperoxy-2-ethylhexanoate, n-butyl-4,4-di(t-butylperoxy)valerate, 1,1-di(t-butylperoxy)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, 2,2-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.

In the present invention, it is preferable to use a polymerization initiator containing an acylphosphine oxide polymerization initiator, and it is preferable to use a polymerization initiator containing an acylphosphine oxide polymerization initiator and another polymerization initiator, particularly an α-hydroxyalkylphenone polymerization initiator. Alternatively, it is also possible to use a polymerization initiator containing an acylphosphine oxide polymerization initiator, an α-hydroxyalkylphenone polymerization initiator, and a peroxide polymerization initiator.
The amount of the acylphosphine oxide polymerization initiator used in the polymerization initiator is, when the total amount of the polymerization initiator is taken as 100% by mass, for example, 1% by mass or more, preferably 10% by mass or more, and more preferably 20% by mass or more, and for example, 100% by mass or less, preferably 95% by mass or less, and more preferably 80% by mass or less.
The amount of the α-hydroxyalkylphenone polymerization initiator used in the polymerization initiator is, when the total amount of the polymerization initiator is taken as 100% by mass, for example, 1% by mass or more, preferably 10% by mass or more, and more preferably 20% by mass or more, and for example, 99% by mass or less, preferably 95% by mass or less, and more preferably 80% by mass or less.

The content of component (D) in the curable artificial nail composition of the present invention is not particularly limited. For example, it is 0.05% by mass or more, preferably 0.1% by mass or more, and for example, 10% by mass or less, preferably 5% by mass or less, based on 100% by mass of the total amount of components (A) to (D) in the curable artificial nail composition. If the content of component (D) is less than 0.05% by mass, the curability of the curable artificial nail composition may be impaired, the curing of the curable artificial nail composition may take a long time, and in some cases, the curing may become impossible. If the content exceeds 10% 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 turn yellow.

[Other ingredients]
In addition to the components (A) to (D), various additives may be added to the curable artificial nail composition within the range that does not adversely affect the viscosity, application properties, handling properties, and durability of the cured coating film.
Examples of such additives include one or more selected from the group consisting of various additives such as radically polymerizable unsaturated group-containing compounds other than components (A) to (C) (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 antifoaming agents, silane coupling agents such as γ-glycidoxypropyltrimethoxysilane, photopolymerization accelerators such as tertiary amines, chain transfer agents, fillers, surface tension modifiers, flame retardants, antioxidants, ion adsorbents, stress reducers, preservatives, antibacterial agents, flexibility-imparting agents, waxes, halogen trapping agents, leveling agents, and wetting improvers.

<Other radical polymerizable compounds>
The other radically polymerizable unsaturated group-containing compound is a compound having a radically polymerizable unsaturated group other than a (meth)acryloyl group. The radically polymerizable unsaturated group is a functional group having a carbon-carbon double bond (also called a polymerizable double bond), such as a vinyl group, a vinyl ether group, or an allyl group.
Examples of other radical polymerizable compounds include one or more compounds selected from the group consisting of allyl glycidyl ether, styrene, α-methylstyrene, vinyl toluene, α-chlorostyrene, vinyl acetate, and the like.

<Coloring Agent>
The colorant may be one or more selected from the group consisting of pigments, luster materials, and dyes, and may be used in any amount to impart a desired color tone to the curable artificial nail composition. In particular, the colorant may be one or more selected from the group consisting of inorganic pigments, luster materials, organic pigments, and dyes used in nail coatings, and does not significantly inhibit curing by ultraviolet irradiation (light irradiation).
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.

Examples of colorants include brown No. 201, black No. 401, purple No. 201, 401, blue No. 1, 2, 201 to 205, 403, 404, green No. 201, 202, 204, 205, 3, 401, 402, yellow No. 201, 202-(1), 202-(2), 203, 204, 205, 4, 401, 402, 403-(1), 404, 405, 406, orange No. 201, 203, 204, 205, 206, 207, 401, 402, 403, red No. 102, 104-(1), 105-(1), 106, 2, 201, Examples include one or more selected from the group consisting of 202, 203, 204, 205, 206, 207, 208, 213, 214, 215, 218, 219, 220, 221, 223, 225, 226, 227, 228, 230-(1), 230-(2), 231, 232, 3, 401, 405, 501, 502, 503, 504, 505, Red No. 506, titanium oxide, iron oxide, chromium oxide, manganese violet, carbon black, metal powder, metal flakes, metal oxide flakes, glass flakes, etc.

<Multifunctional thiol compounds>
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, dipentaerythritol, etc. 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), dipentaerythritol hexakis(3-mercaptopropionate), etc.
When the polyfunctional thiol compound is contained in the curable artificial nail composition, the polyfunctional thiol compound can be contained in an amount of, for example, 1.0% by mass or more and 10.0% by mass or less, where the entire curable artificial nail composition is taken as 100% by mass.

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, 1,4-cyclohexanedimethanol, trimethylolpropane, pentaerythritol, and the like.

The polyester polyol may be one or more selected from the group consisting of condensation polyester polyols, addition polymerization polyester polyols, polycarbonate polyols, etc. The condensation polyester polyol may be obtained by a condensation reaction of one or more diol compounds selected from the group consisting of ethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,4-hexanedimethanol, dimer acid diols, polyethylene glycol, etc. with one or more organic polybasic acids selected from the group consisting of adipic acid, isophthalic acid, terephthalic acid, sebacic acid, etc., and preferably has a molecular weight of 100 to 100,000. The addition polymerization polyester polyol may be polycaprolactone, and preferably has 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.
The polyether polyol may be, for example, a polyether polyol obtained by the opening polymerization of an alkylene oxide.

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, for example, 500 ppm by mass or more, preferably 1,000 ppm by mass or more, and for example, 5,000 ppm by mass or less, preferably 4,500 ppm by mass or less, relative to the entire curable artificial nail composition.

The resin is not particularly limited as long as it is neither polymerizable nor a polyol compound. Examples 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.

The solvent is not particularly limited as long as it can dilute the curable artificial nail composition and adjust the viscosity during application. Examples include 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; acetate esters such as methyl acetate, ethyl acetate, and butyl acetate; and diacetone alcohol.

[Uses, properties, etc. of the curable artificial nail composition]
The curable artificial nail composition of the present invention has a gloss value of more than 140 and exhibits high gloss and excellent luster both when a cured coating film is formed by irradiation with a UV lamp and when a cured coating film is formed by irradiation with an LED lamp.
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 applied to the surface of a user's own nail, which may be sanded, if necessary, to form an uneven surface.
The curable artificial nail composition of the present invention can be particularly suitably used as a gel nail. For example, whether it is used to form a base coat layer that is applied directly to a user's nail, a color coat layer that is applied on top of the base coat layer, or a top coat layer that is applied on top of that, 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.

The curable artificial nail composition of the present invention provides a cured coating film with high gloss and excellent luster, making it suitable for use in forming a top coat layer for gel nails. It is particularly suitable for use as a clear top coat, a glitter-containing clear top coat containing a lustrous material such as metal powder, metal flakes, metal oxide flakes, or glass flakes, or a color coat layer toned with a desired colorant. Furthermore, after applying the curable artificial nail composition of the present invention and before curing, small decorations or powders can be attached to the coating surface of the curable artificial nail composition to enhance the design.

When forming a cured coating film of the curable artificial nail composition of the present invention, equipment similar to that used for conventional radically polymerizable nail polishes that are cured by ultraviolet light or the like, or general ultraviolet curing equipment, is used.
In particular, when irradiated with UV light (wavelength 350 to 400 nm; peak wavelength about 365 nm, about 370 nm, about 375 nm, or about 380 nm) from a mercury lamp or metal halide lamp, or ultraviolet light-emitting diode (UV-LED) light (wavelength 385 to 415 nm; peak wavelength about 405 nm), a cured coating film having excellent curability and a high gloss can be formed. Furthermore, ultraviolet light sources such as ultraviolet laser diodes (UV-LDs) can also be used.
When the applied coating film of the curable artificial nail composition is cured by irradiating it with light such as ultraviolet (UV) light, the irradiation energy required for curing varies depending on the composition of the curable artificial nail composition, but the irradiation energy (cumulative light amount) is, for example, 5 mJ/ ^cm2 or more, preferably 10 mJ/ ^cm2 or more, and for example, 1000 mJ/ ^cm2 or less, preferably 800 mJ/ ^cm2 or less. If the irradiation energy is within this range, nail art with sufficient adhesion and abrasion resistance can be obtained.

The cured coating film of the curable artificial nail composition of the present invention has a reduced content of unpolymerized curable components that are the cause of polymerization inhibition by oxygen, etc., so the cured coating film is not damaged when wiped off with a solvent such as ethanol, isopropanol, ethyl acetate, or acetone, and has a high gloss and excellent shine.

The curable artificial nail composition of the present invention only needs to have a viscosity that allows it to be applied sufficiently with an application tool such as a brush.
The curable artificial nail composition preferably has a stress (maximum stress) at break in a tensile test of the cured coating film of 15.0 MPa or more, more preferably 18.0 MPa or more, and even more preferably 20.0 MPa or more. If the stress is less than 15.0 MPa, the composition may be prone to peeling due to rubbing.
The strain at break of the cured coating film is preferably 95.0% or more, more preferably 97.0% or more, and even more preferably 100.0% or more.

[Coating Nails with Curable Artificial Nail Composition]
The nails to be coated with the curable artificial nail composition of the present invention may be either 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 a coating film on a nail to coat it, the coated 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 inkjet can be used.

Alternatively, an uncured layer having the shape of a nail or the like can be formed on one side of a sheet using the curable artificial nail composition of the present invention, and after bringing this layer into contact (transferring) with the nail surface, the layer can be cured by irradiating it with ultraviolet light, with or without peeling off the sheet.
According to the method of forming a layer of a curable artificial nail composition on the surface of a sheet in advance 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, which is advantageous.

The present invention will be explained in more detail below using examples, but the present invention is not limited to these examples. Unless otherwise specified, "%" means "% by mass" and "parts" means "parts by mass."

<Examples 1 to 5, Comparative Examples 1 to 6>
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, respectively, and the mixture was heated to 50°C while stirring with a dissolver and stirred for 1 hour. After stirring, the mixture was allowed to stand for 2 hours and degassed to obtain a curable artificial nail composition. All of these steps were performed in the dark.

<Comparative Examples 7 and 8>
As Comparative Example 7, a commercially available curable artificial nail composition containing a urethane acrylate oligomer, a (meth)acrylate monomer, and TPO was used.
As Comparative Example 8, a commercially available curable artificial nail composition containing urethane acrylate oligomer, IBXMA, TPO and 184 was used.

The components constituting the curable artificial nail composition are the following compounds.
UA1: A polyurethane (meth)acrylate oligomer obtained by reacting a polyurethane oligomer having an average of nine repeating units obtained from 1,4-butanediol and isophorone diisocyanate (IPDI) and having an isocyanate group at the end with two moles of hydroxyethyl acrylate (cosmetic ingredient name: BisHEA (poly(1,4-butanediol)-9/IPDI) copolymer).
UA2: A polyurethane (meth)acrylate oligomer obtained by reacting a polyurethane oligomer having an average of nine repeating units obtained from 1,4-butanediol and isophorone diisocyanate and having an isocyanate group at the end with two moles of hydroxyethyl methacrylate (cosmetic ingredient name: bisHEMA (poly(1,4-butanediol)-9/IPDI) copolymer).
Bis-GMA: isopropylidenediphenylbis(oxyhydroxypropyl methacrylate)
IBXA: Isobornyl acrylate, IBXMA: Isobornyl methacrylate, HEMA: 2-hydroxyethyl methacrylate, TPO: 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 184: 1-hydroxycyclohexylphenyl ketone, UA3: Dicarbamate, trimethylhexyl HEA (cosmetic ingredient name)
UA4: Polyurethane-74 (Ingredient name in cosmetics: A copolymer obtained by reacting a polyester prepolymer condensed from diethyl carbonate, hexanediol, glycol, and ε-caprolactone with neopentyl glycol mono(hydroxypivalate) and isophorone diisocyanate (IPDI), blocked with 2-hydroxyethyl acrylate)

<Gloss value (UV lamp curing)>
The resulting curable artificial nail composition was applied to a rigid polyvinyl chloride plate to form a coating film of a constant thickness (100 μm), which was then cured by irradiating it with a 36 W UV lamp (irradiation wavelength 365 nm) for 60 seconds. The resulting cured coating film was wiped to remove any uncured components using an 80% aqueous ethanol solution. The rigid polyvinyl chloride plate was then placed on black drawing paper, and the gloss value (UV lamp curing) was determined using a gloss checker (IG-310, manufactured by Horiba, Ltd.). The results are shown in Tables 1 and 2.

<Gloss value (LED lamp curing)>
The resulting curable artificial nail composition was applied to a rigid polyvinyl chloride plate to form a coating film of a constant thickness (100 μm), which was then cured by irradiating it with a 30 W LED lamp (irradiation wavelength 405 nm) for 30 seconds. The resulting cured coating film was wiped to remove any uncured components using an 80% aqueous ethanol solution. The rigid polyvinyl chloride plate was then placed on black drawing paper, and the gloss value (LED lamp curing) was determined using a gloss checker (IG-310, manufactured by Horiba, Ltd.). The results are shown in Tables 1 and 2.

From Table 1, it can be seen that the curable artificial nail compositions of Examples 1 to 5 according to the present invention, which contain the components (A), (B), (C), and (D), have a gloss value of more than 140 for both the cured coating films obtained by irradiation with a UV lamp and the cured coating films obtained by irradiation with an LED lamp, and thus have a high gloss and excellent luster.
On the other hand, Table 2 shows that the curable artificial nail compositions of Comparative Examples 1 to 8, which do not contain component (A) and/or component (B), have a cured coating film obtained by irradiation with an LED lamp with a gloss value of less than 140, and also have a cured coating film obtained by irradiation with a UV lamp with a gloss value of less than 140 in some cases, resulting in low gloss and problems with luster.

Claims (2)

Component (A): At least a compound of formula (1):
-OCONH-R ¹ -NHCOO-R ² - (1)
(In the formula, ^R1 is a divalent organic group containing an alicyclic structure, and ^R2 is an aliphatic hydrocarbon group that is an alkylene group .)
A urethane (meth)acrylate oligomer having a repeating unit represented by the formula:
Component (B): At least a compound of formula (2):
[CH ₂ =CHR ³ -COO-R ⁴ -CH ₂ -CH(OH)-CH ₂ -O-] _p R ⁵ (OH) _q (2)
(In the formula, ^R3 is hydrogen or a methyl group, ^R4 is a single bond or a group represented by ^-R6 -O- ( ^R6 is a divalent organic group), ^R5 is a divalent or higher aromatic hydrocarbon group, p is an integer of 1 or greater, and q is an integer of 0 or greater.)
An acrylate compound having a structure represented by the formula:
Component (C): a (meth)acrylate compound other than components (A) and (B),
Component (D): polymerization initiator,
1. A curable artificial nail composition comprising:
the content of the component (A) is 80% by mass or less, where the total amount of the components (A) to (D) in the curable artificial nail composition is 100% by mass;
the content of the component (B) is 5% by mass or more and 30% by mass or less, relative to 100% by mass of the total amount of the components (A) to (D) in the curable artificial nail composition;
the content of the component (C) is 5% by mass or more and 40% by mass or less, relative to 100% by mass of the total amount of the components (A) to (D) in the curable artificial nail composition;
the content of the component (D) is 0.05% by mass or more and 10% by mass or less, where the total amount of the components (A) to (D) in the curable artificial nail composition is 100% by mass . 2. The curable artificial nail composition according to claim 1, wherein the content of component (B) is 5 parts by mass or more and 40 parts by mass or less per 100 parts by mass of the total of components (A) and (C).