JP2024021294A - Photocurable gel nail composition, and gel nail method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gel nail composition or the like, demonstrating a very rapid curing rate, few unreacted components, and superior non-wipe properties, while ensuring superior storage stability even at relatively high temperatures.

SOLUTION: The present invention provides a gel nail composition or the like, comprising, as its constituents, an urethane acrylate resin as well as a specific amount of a monofunctional (meth)acrylate monomer, a specific amount of a polyfunctional (meth)acrylate monomer, a specific amount of a photopolymerization initiator, a specific amount of a polyfunctional thiol compound, and a specific amount of a polymerization inhibitor.

SELECTED DRAWING: Figure 1

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present invention relates to a photocurable gel nail composition (hereinafter sometimes simply referred to as a gel nail composition) and a gel nail method using the same.
In particular, the present invention relates to a composition for gel nails that has an extremely fast curing speed, excellent non-wipeability (few unreacted substances), and excellent storage stability even at relatively high temperatures, and a gel nail method using the composition.

In recent years, photocurable gel nails have been actively developed and various proposals have been made because they do not contain a significant amount of organic solvent, have a fast curing reaction, and are excellent in durability.
As such photocurable gel nails, even if the container containing the photocurable artificial nail composition is stored for a long period of time once opened, it will not harden, the viscosity will increase, and the coating properties will not deteriorate. Curable artificial nail compositions have been proposed (see, for example, Patent Document 1).
More specifically, it contains a urethane (meth)acrylate oligomer, a (meth)acrylate monomer, a polyfunctional thiol compound, a polymerization initiator, and a tocopherol compound as a polymerization inhibitor, and the amount of the tocopherol compound is 1, This is a photocurable artificial nail composition with a concentration of 000 to 5,000 ppm.
In addition, the amount of tocopherol compound blended is in the range of 0.01 to 0.1 part by weight with respect to 1 part by weight of the polymerization initiator, and the blended amount of tocopherol compound is set in the range of 0.01 to 0.1 part by weight with respect to 1 part by weight of the polyfunctional thiol compound. A preferred embodiment is a range of 0.01 to 0.1 parts by weight.

In addition, as a photocurable artificial nail composition that does not harden, increase viscosity, and exhibit poor applicability even after long-term storage, tert-butylhydroquinone is used instead of tocopherol compounds to inhibit polymerization. A photocurable artificial nail composition used as an agent has been proposed (see, for example, Patent Document 2).
More specifically, the photocurable artificial nail composition contains a polyfunctional thiol compound and tert-butylhydroquinone, and the content of tert-butylhydroquinone is 300 to 4,500 ppm.

In addition, it has excellent surface gloss, operability, adhesive durability, low curing heat generation, and stain resistance, as well as good surface curing properties, and after curing using ultraviolet and/or visible light, it can be used with wipes, etc. A photocurable artificial nail composition has been proposed that does not require a step of removing an unpolymerized layer on the surface of the cured product (see, for example, Patent Document 3).
More specifically, it is a photocurable artificial nail composition characterized by containing the following ingredients (A1) to (E1).
(A1) Urethane (meth)acrylate oligomer having at least one (meth)acrylate group and at least one urethane bond in one molecule (B1) Having two or more thiol groups in one molecule Polyfunctional thiol compound (C1) A radically polymerizable compound (D1) having one or more radically polymerizable unsaturated bonds in one molecule, which does not fall under the components (A1) and (B1), and the photopolymerization initiator (E1) chain transfer agent

Patent No. 6755544 (Claims, etc.) JP2019-34897A (Claims, etc.) JP2019-6689A (Claims, etc.)

However, the photocurable artificial nail composition disclosed in Patent Document 1 contains a predetermined amount of a tocopherol compound as a polymerization inhibitor, and the amount of the tocopherol compound is adjusted to a polymerization initiator and a polyfunctional thiol compound. On the other hand, even if each ratio was limited to a predetermined ratio, there was still a problem of poor storage stability.
That is, even if the blending amount of the tocopherol compound was limited to a predetermined ratio with respect to the polymerization initiator and the polyfunctional thiol compound, there was still a problem of poor storage stability.
More specifically, when the storage temperature is around 40°C, it shows a certain level of storage stability, but when the storage temperature reaches a relatively high temperature condition such as 60°C, the storage stability decreases rapidly, and the gel is lost in a short period of time. The problem was that it was easy to cause oxidation, etc.

Furthermore, although the photocurable artificial nail composition disclosed in Patent Document 2 contains a predetermined amount of tert-butylhydroquinone compound as a polymerization inhibitor, it may be carcinogenic and may be inferior in safety. A problem was found.
Moreover, even if the amount of the tert-butylhydroquinone compound is limited to a predetermined ratio with respect to the polymerization initiator and the polyfunctional thiol compound, the storage stability under relatively high temperature conditions such as 60°C is still poor. This problem was found.
Therefore, if a part of the photocurable artificial nail composition is used and the remaining part is stored, there has been a problem that gelation or the like tends to occur during the storage period, depending on the storage temperature.

Furthermore, the photocurable artificial nail composition disclosed in Patent Document 3 had to contain a predetermined amount of a chain transfer agent as a compounding component.
As a result, the reaction cannot be precisely controlled, resulting in excessive curing, resulting in a significant decrease in gloss and warping, or, conversely, insufficient curing, resulting in a large amount of unreacted materials. There was a problem that it was easy to remain.
Furthermore, there was a problem that there was a poor balance between photocurability and storage stability, and it was difficult to stably cure unless ultraviolet rays of a predetermined wavelength were irradiated with precision in an extremely narrow range. .

Therefore, as a result of intensive studies, the present inventors found that by using a specified polymerization inhibitor instead of a polymerization inhibitor such as a tert-butylhydroquinone compound or a tocopherol compound for a specified urethane acrylate resin, it was possible to improve the reciprocal property. The present invention was completed based on the discovery that a gel nail composition with excellent reactivity and storage stability can be obtained.
In other words, by incorporating a predetermined amount of a predetermined polymerization inhibitor, a composition for gel nails has an extremely fast curing speed, excellent non-wipeability, and excellent storage stability even under relatively high temperature conditions, and its use. The purpose is to provide a method.

According to the present invention, there is provided a photocurable gel nail composition characterized by containing the following components (A) to (F) as compounded components, and the above-mentioned problems can be solved.
(A) Urethane acrylate resin 100 parts by weight (B) Monofunctional (meth)acrylate monomer 1 to 30 parts by weight (C) Multifunctional (meth)acrylate monomer 20 to 120 parts by weight (D) Photopolymerization initiator 1 to 30 parts by weight Part (E) Polyfunctional thiol compound containing two or more thiol groups in one molecule
1 to 30 parts by weight (F) A polymerization inhibitor containing a metal salt of a nitroso compound and/or a phenol compound 0.01 to 5 parts by weight In other words, in this way, components (A) to (F) are mixed in predetermined amounts. When photopolymerized, it is possible to provide a photocurable gel nail composition that has an extremely fast curing speed (for example, an irradiation time of 15 seconds) and has excellent non-wipe properties.
On the other hand, excellent storage stability can be obtained even at relatively high temperatures (for example, 60° C. for 30 days) without substantially using a polymerization inhibitor such as a tert-butylhydroquinone compound or a tocopherol compound.

Furthermore, in constituting the photocurable gel nail composition of the present invention, the ratio (by weight) of (F) polymerization inhibitor blending amount/(E) polyfunctional thiol compound blending amount is 0.01 to 0. It is preferable to set the value within the range of .6.
By further considering the ratio of component (F)/component (E) in this way, a composition for gel nails that has an excellent balance between excellent photocurability and storage stability when photopolymerized can be obtained. can be provided.

In constituting the photocurable gel nail composition of the present invention, the metal salt of the nitroso compound is preferably a metal salt of N-nitroso-N-phenylhydroxylamine.
In this way, by using at least a metal salt of a specified nitroso compound as component (F), when photopolymerized, it has excellent non-wipe properties and also has excellent storage stability even at relatively high temperatures. It is possible to provide a composition for gel nails that exhibits the following properties.

In constituting the photocurable gel nail composition of the present invention, the phenol compound is preferably 4-methoxyphenol.
Thus, by using 4-methoxyphenol as component (F), when photopolymerized, it exhibits excellent non-wipe properties and also exhibits excellent storage stability even at relatively high temperatures. A composition for gel nails can be provided.

Further, in constituting the photocurable gel nail composition of the present invention, (A) urethane acrylate resin contains at least urethane acrylate resin (a1) having a weight average molecular weight within the range of 500 to 30,000. is preferred.
By considering the weight average molecular weight of component (A) in this way, when photopolymerized, the curing speed becomes faster and non-wipeability is improved, while the miscibility with other ingredients is improved. It is possible to provide a gel nail composition with improved storage stability.

In constituting the photocurable gel nail composition of the present invention, (B) the monofunctional (meth)acrylate monomer includes (meth)acryloylmorpholine, ethyl (meth)acrylate, and 2-hydroxyethyl (meth)acrylate. ) is preferably at least one compound selected from the group consisting of acrylates.
By considering the type of component (B) in this way, it is possible to adjust the glass transition point to a relatively high value when photopolymerized, and to provide a composition for gel nails that has little odor and relatively low viscosity. be able to.

In addition, in constituting the photocurable gel nail composition of the present invention, (E) a polyfunctional thiol compound containing two or more thiol groups in one molecule (hereinafter simply referred to as a polyfunctional thiol compound) ) is preferably a polyfunctional secondary thiol compound.
By considering the type of component (E) in this way, the curing speed (irradiation time about 15 seconds) can be stabilized and the curing rate can be extremely fast, and while the non-wipe property can be excellent, it can also be achieved at relatively high temperatures (e.g. 60°C, 30°C). Excellent storage stability can be obtained for up to 30 days.

Another aspect of the present invention is a gel nail method using any one of the photocurable gel nail compositions described above, comprising the following steps (1) to (4). This is a gel nail method.
(1) Step of preparing a composition for photocurable gel nails (2) Step of applying the composition for photocurable gel nails to form a coating layer (3) Photocuring the coating layer to form a cured film Step (4) Step of peeling off the cured film after use As described above, using a photocurable gel nail composition that has excellent reactivity and storage stability, which are contradictory properties, a prescribed gel nail method can be applied. By performing this, a cured film with excellent non-wipe properties can be efficiently obtained.

FIG. 1 is a diagram provided to explain the relationship between the blending amount of the polymerization inhibitor (F), curability, and storage stability at 60°C. FIG. 2 is a diagram provided to explain the relationship between the metal salt ratio of (F1) phenol compound/(F2) nitroso compound, curability, and storage stability at 60°C. FIG. 3 is a diagram provided to explain the relationship between the ratio of (F) polymerization inhibitor/(E) polyfunctional thiol and curability and storage stability at 60°C. FIG. 4 is a diagram provided to explain the relationship between the ratio of (F) polymerization inhibitor/(D) polymerization initiator and curability and storage stability at 60°C. FIG. 5 is a diagram provided to explain the relationship between the elapsed time and the rate of increase in viscosity when the gel nail composition is stored at 60°C. FIGS. 6(a) to 6(b) are diagrams provided to explain gel nail stickers, which are one of the uses of the present invention, and FIGS. 6(c) to (d) are views, which are one of the uses. It is a figure provided in order to explain a gel nail tip. FIGS. 7(a) to 7(c) are diagrams provided to explain a method of forming a gel nail layer having a single-layer structure. FIGS. 8(a) to 8(d) are diagrams provided to explain a method for forming a gel nail layer having a multilayer structure.

[First embodiment]
A first embodiment of the present invention is a photocurable gel nail composition characterized by containing the following components (A) to (F) as compounded components.
(A) Urethane acrylate resin 100 parts by weight (B) Monofunctional (meth)acrylate monomer 1 to 30 parts by weight (C) Multifunctional (meth)acrylate monomer 20 to 120 parts by weight (D) Photopolymerization initiator 1 to 30 parts by weight Part (E) Polyfunctional thiol compound containing two or more thiol groups in one molecule
1 to 30 parts by weight (F) 0.01 to 5 parts by weight of a polymerization inhibitor containing a metal salt of a nitroso compound and/or a phenol compound

1. Ingredients (A)
The compounding component (A) is a urethane acrylate resin.
The form of the urethane acrylate oligomer is not particularly limited, but, for example, it is preferably a urethane acrylate oligomer having a weight average molecular weight of 500 to 8,000.
The reason for this is that by using a urethane acrylate oligomer with such a weight average molecular weight, it is possible to improve the curing speed and shorten the curing time while effectively maintaining adhesion to the nail. Another reason is that it is possible to easily obtain a predetermined hardness as a cured coating film.
That is, if the weight average molecular weight of the urethane acrylate oligomer is less than 500, the curing rate will increase excessively, and it will likely cause poor adhesion to the nail, making handling difficult.
On the other hand, when the weight average molecular weight of the urethane acrylate oligomer exceeds 8,000, the curing speed decreases, the curing time becomes excessively long, and the durability of the cured coating film cannot be effectively adjusted. This is because it may be difficult.
Therefore, it is more preferable that the weight average molecular weight of the urethane acrylate oligomer is within the range of 1,000 to 6,000, and even more preferably within the range of 3,000 to 5,000.

Moreover, it is preferable that the urethane acrylate oligomer is a polyester skeleton urethane acrylate oligomer.
That is, it is preferably a reaction product of a polyester skeleton polyol, an organic polyisocyanate compound, and a hydroxyacrylate.
The reason for this is that by using a polyester skeleton urethane acrylate oligomer, a predetermined photocuring reactivity can be obtained, while photocuring shrinkage is relatively small, making it easy to obtain excellent adhesion and flexibility.

Here, the type of polyester skeleton polyol for obtaining the polyester skeleton urethane acrylate oligomer is not particularly limited, but polyester skeleton diol compounds are used because they are easily available industrially and are relatively inexpensive. It is preferable that there be.
Furthermore, as the type of organic polyisocyanate compound for obtaining the polyester skeleton urethane acrylate oligomer, at least one non-yellowing type such as isophorone diisocyanate, hexamethylene diisocyanate, 4,4-dicyclohexylmethane diisocyanate, and trimethylhexamethylene diisocyanate is preferable.
Furthermore, as the hydroxyacrylate for obtaining the polyester skeleton urethane acrylate oligomer, at least one of 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, caprolactone-modified 2-hydroxyethyl acrylate, etc. is preferable.

(2) Blending amount In addition, the blending amount of the urethane acrylate oligomer may be within the range of 30 to 80% by weight based on the total amount (100% by weight) including components (A) to (F). preferable.
The reason for this is that it is possible to easily obtain a predetermined hardness as a cured coating while effectively maintaining adhesion to nails.
In other words, if the amount of the urethane acrylate oligomer is less than 30% by weight, the curing speed will decrease, the curing time will become excessively long, and the water absorption rate and durability of the cured coating film may not be effectively adjusted. This is because it may be difficult to do so.
On the other hand, if the amount of urethane acrylate oligomer exceeds 80% by weight, it may be difficult to control the curing speed, or it may tend to adhere poorly to nails, making it difficult to handle. It's for a reason.
Therefore, the amount of urethane acrylate oligomer blended is preferably within the range of 35 to 75% by weight, and more preferably within the range of 40 to 70% by weight, based on the total amount.

(3) Urethane acrylate oligomer mixture It is also preferable to use a mixture of a polyester skeleton urethane acrylate oligomer and other urethane acrylate oligomers as the urethane acrylate oligomer.
Examples of such other urethane acrylate oligomers include at least one of polyester skeleton urethane acrylate oligomers having a weight average molecular weight as described below, polycaprolactone-based urethane acrylate oligomers, polycarbonate-based urethane acrylate oligomers, and polyether-based urethane acrylate oligomers. It will be done.
In particular, other urethane acrylate oligomers include polyester skeleton urethane acrylate oligomers having a weight average molecular weight (10,000 to 25,000), which will be described later, and polyester skeleton urethane acrylate oligomers having a predetermined weight average molecular weight (500 to 8,000). It is preferable to use a mixture of and.
The reason for this is that by using multiple polyester skeleton urethane acrylate oligomers with different weight average molecular weights, a predetermined curing speed can be effectively maintained during curing, while improving adhesion to nails after curing. This is because it can be done.

Further, it is preferable that the weight average molecular weight of other urethane acrylate oligomers other than the polyester skeleton urethane acrylate oligomer is within the range of 10,000 to 25,000.
The reason for this is that if the weight average molecular weight of such other urethane acrylate oligomers is less than 10,000, the curing speed increases and the adhesion to nails tends to be poor, making handling difficult. This is because there is.
On the other hand, if the weight average molecular weight of such other urethane acrylate oligomer exceeds 25,000, the curing rate will decrease, the curing time will become excessively long, and the durability of the cured coating film will not be effectively adjusted. This is because it may be difficult to do so.
Therefore, the weight average molecular weight of the other urethane acrylate oligomer is more preferably within the range of 12,000 to 20,000, and even more preferably within the range of 15,000 to 18,000.

Further, the blending ratio of other urethane acrylate oligomers is preferably within the range of 5 to 25 parts by weight, and preferably within the range of 8 to 20 parts by weight, based on 100 parts by weight of the polyester skeleton urethane acrylate oligomer. It is more preferable that
The reason for this is that if the blending ratio of other urethane acrylate oligomers is too low, the curing rate will increase, making it more likely to cause poor adhesion to nails and making handling difficult. On the other hand, if the blending ratio of other urethane acrylate oligomers is too high, the curing speed may decrease excessively, making it difficult to adjust the durability of the cured coating film.

2. Ingredients (B)
(1) Function The compounding component (B) is a monofunctional (meth)acrylate monomer.
The monofunctional (meth)acrylate monomer is characterized in that it is used in combination with the urethane acrylate resin component (A).
The reason for this is that by blending such a monofunctional (meth)acrylate monomer, the photocurability, non-wipeability, viscosity (ease of use), storage stability, or gain of the photocurable gel nail composition can be improved. This is because it becomes easier to control the adhesion, durability, etc. of the applied gel nails within a desired range.

(2) Types Examples of such monofunctional (meth)acrylate monomers include (meth)acrylic acid, ethyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, and tert-butyl (meth)acrylate, pentyl (meth)acrylate, isoamyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isodecyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, isostearyl (meth)acrylate, Cyclohexyl (meth)acrylate, benzyl (meth)acrylate, isobornyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, phenoxyethyl (meth)acrylate Acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, methoxydiethylene glycol (meth)acrylate, ethoxydiethylene glycol (meth)acrylate, butoxydiethylene glycol (meth)acrylate, 2-ethylhexyldiethylene glycol (meth)acrylate, methoxytriethylene glycol ( meth)acrylate, methoxydipropylene glycol (meth)acrylate, ethoxydipropylene glycol (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, 2-(meth)acryloyloxyethylsuccinic acid, 2-(meth)acryloyloxy Ethylhexahydrophthalic acid, 2-(meth)acryloyloxyethyl phthalate, 2-(meth)acryloyloxyethyl-2-hydroxyethylphthalate, neopentyl glycol-acrylic acid-benzoate, 2-(meth) ) acryloyloxyethyl acid phosphate and the like.
By using such a monofunctional (meth)acrylate monomer, it is possible to adjust the glass transition point to a relatively high value when photopolymerized, and to provide a composition for gel nails that has little odor and relatively low viscosity. be able to.

In particular, among these monofunctional (meth)acrylate monomers, at least one compound selected from the group consisting of (meth)acryloylmorpholine, ethyl (meth)acrylate, and 2-hydroxyethyl (meth)acrylate. It is preferable that there be.
The reason for this is that by using these monofunctional (meth)acrylate monomers, not only can the curing speed when photocuring the photocurable gel nail composition be made faster, but also the curing speed can be increased. This is because the releasability can be further improved while maintaining excellent adhesion.
Furthermore, these monofunctional (meth)acrylate monomers are also excellent as reactive diluents, making it possible to easily adjust the viscosity of gel nail compositions and improve handling properties.
Note that monofunctional (meth)acrylate means monofunctional "acrylate and/or methacrylate." The same applies to polyfunctional (meth)acrylates described below.

(3) Blending amount The blending amount of (B) monofunctional (meth)acrylate is within the range of 1 to 30 parts by weight based on 100 parts by weight of (A) urethane acrylate oligomer. do.
The reason for this is that while effectively maintaining a predetermined curing speed, it is possible to not only improve adhesion to the nail, but also to obtain a cured coating that is less irritating to the nail and surrounding skin. It is.

In other words, if the amount of monofunctional (meth)acrylate monomer blended is less than 1 part by weight with respect to 100 parts by weight of urethane acrylate oligomer, the curing rate increases, making it difficult to control curability, and causing problems in adhesion to nails. This is because defects may easily occur and handling may become difficult.
On the other hand, if the amount of the monofunctional (meth)acrylate monomer exceeds 30 parts by weight, the curing time may become excessively long or the durability of the resulting cured coating film may not be effectively adjusted. This is because it may be difficult to do so.
Therefore, the amount of the (meth)acrylate monomer to be blended is more preferably within the range of 3 to 25 parts by weight, and more preferably 5 to 20 parts by weight, based on 100 parts by weight of the urethane acrylate oligomer having a predetermined weight average molecular weight. It is more preferable to set the value within the range of .
However, when using the above-mentioned isobornyl (meth)acrylate, it is more preferably a value within the range of 1 to 15 parts by weight, and a value within the range of 1 to 10 parts by weight, based on 100 parts by weight of the urethane acrylate oligomer. It is more preferable that
Furthermore, even when the above-mentioned isobornyl (meth)acrylate is used, it is more preferable that the value is 1% by weight or less, and 0.5% by weight or less, based on the total amount of the gel nail composition. It is more preferable to set the value to 0.1% by weight or less.
In other words, when using isobornyl (meth)acrylate, it has excellent curing properties and adhesion, but if the amount used increases, it may generate heat during curing and generate an odor when handling gel nails, so be careful. Should.

3. Ingredients (C)
(1) Function The compounding component (C) is a polyfunctional (meth)acrylate monomer.
By using such a polyfunctional (meth)acrylate monomer, it cooperates with other ingredients to improve the gel nail composition's excellent photocurability, non-wipeability, storage stability at relatively high temperatures, and This is because it becomes easier to control the adhesion, durability, etc. of the obtained gel nails within a desired range.

(2) Type The type of polyfunctional (meth)acrylate monomer is not particularly limited, but examples include itaconic acid, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, Ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6- Hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 3-methyl-1,5pentanediol di(meth)acrylate, 2-hydroxy-3- Acryloyloxypropyl methacrylate, glycerin dimethacrylate, ethylene oxide modified bisphenol A di(meth)acrylate, PO adduct di(meth)acrylate of bisphenol A, dimethylol-tricyclodecane di(meth)acrylate, trimethylolpropane tri(meth)acrylate ) acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, ethoxylated pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, ethoxylated isocyanurate At least one of acid tri(meth)acrylate, trifluoroethyl(meth)acrylate, etc. is mentioned.

In addition, as high molecular weight monomers having a polyether skeleton, there are polyether (meth)acrylate oligomers, such as methoxypolyethylene glycol (meth)acrylate, phenoxypolyethylene glycol (meth)acrylate, polyethylene glycol di(meth)acrylate, and polypropylene glycol di(meth)acrylate. At least one of (meth)acrylate and the like can be mentioned.

In particular, among these polyfunctional (meth)acrylate monomers, ethylene oxide modified bisphenol A di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate Preferably, it is at least one compound selected from the group consisting of:
The reason for this is that with these polyfunctional (meth)acrylate monomers, when a gel nail composition is photocured, it becomes a gel that has excellent non-wipe properties and excellent storage stability at a considerable temperature. This is because it becomes easier to provide the nail composition.

(3) Blending amount The blending amount of (C) polyfunctional (meth)acrylate is within the range of 20 to 120 parts by weight based on 100 parts by weight of (A) urethane acrylate oligomer. do.
The reason for this is that while effectively maintaining a predetermined curing speed, it is possible to not only improve adhesion to the nail, but also to obtain a cured coating that is less irritating to the nail and surrounding skin. It is.
In other words, if the amount of the polyfunctional (meth)acrylate monomer blended is less than 20 parts by weight with respect to 100 parts by weight of the urethane acrylate oligomer, the curing rate increases, making it difficult to control the curing property, and causing poor adhesion to the nail. This is because defects may easily occur and handling may become difficult.
On the other hand, if the amount of the polyfunctional (meth)acrylate monomer exceeds 120 parts by weight, the curing speed will decrease, the curing time will become excessively long, and the durability of the cured coating film will be effectively reduced. This is because it may be difficult to make adjustments.
Therefore, it is more preferable that the amount of the polyfunctional (meth)acrylate monomer is within the range of 30 to 110 parts by weight, and more preferably within the range of 40 to 100 parts by weight, based on 100 parts by weight of the urethane acrylate oligomer. It is more preferable to set it as a value.

4. Ingredients (D)
(1) Function (D) Component is characterized by containing a predetermined amount of a photopolymerization initiator.
Such a photopolymerization initiator may be one that generates radicals when exposed to ultraviolet rays and causes the radicals to polymerize urethane acrylate oligomers and monofunctional and polyfunctional (meth)acrylate monomers.

(2) Types Specific examples of such photopolymerization initiators include benzyl dimethyl ketal compounds such as 2,2-dimethoxy-1,2-diphenylethan-1-one, oligo[2-hydroxy-2-methyl α-hydroxyketone compounds such as -1-[4-(1-methylvinyl)phenyl]propanone], 1-hydroxycyclohexylphenylketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 2-methyl-1[4-(methylthio)phenyl]-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1, etc. α-aminoketone compounds, acylphosphine oxide compounds such as diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, 1-[4-(4-benzoylphenylsulfanyl)phenyl]-2-methyl-2- Ketosulfone compounds such as (4-methylphenylsulfonyl)propan-1-one, bis(η5-2,4-cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrole- Metallocene compounds such as 1-yl)-phenyl) titanium, 2,4-diethylthioxanthone, isopropylthioxanthone, 1-chloro-4-propoxythioxanthone, 2-(3-dimethylamino-2-hydroxypropoxy)3,4- At least one of thioxanthone compounds such as dimethyl-9H-thioxanthon-9-one-mesochloride may be used.

Particularly, among these photopolymerization initiators, at least one of an acylphosphine oxide compound having a phenyl group, a ketosulfone compound, and an α-hydroxyketone compound is preferred.
The reason for this is that radicals are stably generated by ultraviolet rays, and the radicals react efficiently with the photopolymerizable oligomer and the photopolymerizable monomer mixture, thereby further promoting the curing reaction.

Furthermore, when a compound such as a thioxanthone compound that extracts hydrogen to generate radicals is combined with a hydrogen donor, the curing reaction is accelerated.
Examples of the hydrogen donor include mercapto compounds and amine compounds, of which amine compounds are preferred. Examples of the amine compound include triethylamine, methyldiethanolamine, triethanolamine, diethylaminoethyl acrylate, p-dimethylaminoacetophenone, ethyl p-dimethylaminobenzoate, isoamyl p-dimethylaminobenzoate, N,N-dimethylbenzylamine, Examples include at least one of 4,4'-bis(diethylamino)benzophenone, p-dimethylaminobenzoic acid ethyl ester, and pentyl 4-dimethylaminobenzoate.

Moreover, it is preferable to use a mixture of at least two types of photopolymerization initiators.
In particular, α-hydroxyketone compounds are used in combination with acylphosphine oxide compounds, as they have appropriate curing speed and weather resistance, and can effectively adjust the durability of the cured coating. It is preferable to do so.
In addition, when forming a colorless (clear) gel nail composition that does not contain pigments or use coloring pigments, it is necessary to use a photopolymerization initiator in order to avoid the influence of coloring of the photocured coating film. It is preferred to use only α-hydroxyketone compounds.

(3) Amount of the photopolymerization initiator (D) The amount of the photopolymerization initiator (D) is within the range of 1 to 30 parts by weight based on 100 parts by weight of the urethane acrylate oligomer (A).
The reason for this is that if the amount of the photopolymerization initiator is less than 1 weight, the curing speed may be excessively reduced and the durability of the cured coating may be reduced.
On the other hand, if the amount of the photopolymerization initiator exceeds 30 parts by weight, the curing speed will increase excessively, making it more likely to cause poor adhesion to nails and making handling difficult.
Therefore, it is more preferable that the amount of the photopolymerization initiator (D) is within the range of 2 to 25 parts by weight, and more preferably 3 to 20 parts by weight, based on 100 parts by weight of the urethane acrylate oligomer (A). It is more preferable to set the value within the range.

5. Ingredients (E)
(1) Function The blending component (E) is a polyfunctional thiol compound containing two or more thiol groups in one molecule, and is characterized by blending a predetermined amount of such a polyfunctional thiol compound.
In other words, by using such a polyfunctional thiol compound, the curing speed is extremely fast, and even when the irradiation time is 15 seconds or less, a tackleless product with almost no unreacted substances can be produced by working in cooperation with other ingredients. It can be used as a gel nail composition from which a cured product can be obtained.

(2) Type The type of polyfunctional thiol compound is not particularly limited, but examples include 1,2-ethanedithiol, 1,2-propanedithiol, 1,3-propanedithiol, 1,3 -Butanedithiol, 2,3-butanedithiol, 1,5-pentanedithiol, 1,6-hexanedithiol, 1,8-octanedithiol, 1,9-nonanedithiol, 1,10-decanedithiol, 1,2- Benzenedithiol, 1,3-benzenedithiol, 1,4-benzenedithiol, 3,6-dichloro-1,2-benzenedithiol, toluene-3,4-dithiol, 1,5-naphthalenedithiol, ethylene glycol bis(thio glycolate), ethylene glycol bis(3-mercaptopropionate), 1,4-butanediol bisthioglycolate, tetraethylene glycol bis(3-mercaptopropionate), trimethylolpropane tris(thioglycolate), Trimethylolpropane tris (3-mercaptopropionate), trimethylolpropane tris (3-mercaptobutyrate), tris [(3-mercaptopropionyloxy)-ethyl] isocyanurate, pentaerythritol tetrakis (thioglycolate), Pentaerythritol tetrakis (3-mercaptopropionate), dipentaerythritol hexakis (3-mercaptopropionate), 1,4-bis(3-mercaptobutyryloxy)butane, pentaerythritol tetrakis (3-mercaptobutyrate) ), pentaerythritol tetrakis (3-mercaptobutyrate), 1,3,5-tris(3-mercaptobutyloxyethyl)-1,3,5-triazine-2,4,6(1H,3H,5H)- trione, dimercapto diethyl sulfide, 1,8-dimercapto-3,6-dithiaoctane, 1,2-bis[(2-mercaptoethyl)thio]-3-mercaptopropane, tetrakis(7-mercapto-2,5-dithiaheptyl) ) Methane, trithiocyanuric acid, 1,2-benzenedimethane, thiol, 4,4'-thiobisbenzenethiol, 2-di-n-butylamino-4,6-dimercapto-s-triazine, 2-di-n -Butylamino-4,6-dimercapto-s-triazine, 2,5-dimercapto-1,3,4-thiadiazole, 1,8-dimercapto-3,6-dioxaoctane, 1,5-dimercapto-3- Thiapentane, trimercaptopropionate tris(2-hydroxyethyl)isocyanurate, 1,4-dimethylmercaptobenzene, 2,4,6-trimercapto-s-triazine, 2-(N,N-dibutylamino)-4, 6-dimercapto-s-triazine, bis(4-(2-mercaptopropoxy)phenyl)methane, 1,1-bis(4-(2-mercaptopropoxy)phenyl)ethane, 2,2-bis(4-(2-mercaptopropoxy)phenyl)ethane, -mercaptopropoxy)phenyl)propane, 2,2-bis(4-(2-mercaptopropoxy)phenyl)butane, 1,1-bis(4-(2-mercaptopropoxy)phenyl)isobutane, 2,2-bis( 4-(2-mercaptopropoxy)-3-methylphenyl)propane, 2,2-bis(4-(2-mercaptopropoxy)-5-methylphenyl)propane, bis(2-(2-mercaptopropoxy)-5 -methylphenyl)methane, 2,2-bis(4-(2-mercaptopropoxy)-3-t-butylphenyl)propane, tris(4-(2-mercaptopropoxy)phenyl)methane, 1,1,1- Tris(4-(2-mercaptopropoxy)phenyl)ethane, bis(4-(2-mercaptobutoxy)phenyl)methane, 2,2-bis(4-(2-mercaptobutoxy)phenyl)propane, tris(4- Examples include at least one of alkyl vinyl ether adducts of (2-mercaptobutoxy)phenyl)methane and 1,3,5-triazine-2,4,6-trithiol.

Among these polyfunctional thiol compounds, polyfunctional secondary thiol compounds are particularly preferred, and more specifically, pentaerythritol tetrakis (3-mercaptobutyrate), 1,4-bis(3-mercaptobutyrate), lyloxy)butane, 1,3,5-tris(3-mercaptobutyloxyethyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione and pentaerythritoltetrakis(3- mercaptobutyrate) is more preferred.
The reason for this is that such polyfunctional secondary thiol compounds can effectively suppress thermal addition reactions to monomers (gelation during storage) due to steric hindrance around the thiol group. .
In addition, if such a polyfunctional secondary thiol compound is used, there is less risk of inhibiting polymerization due to oxygen when irradiated with ultraviolet rays, etc., and high curability can be obtained due to the ene-thiol reaction. It is.
Moreover, by using a polyfunctional secondary thiol compound, yellowing of the obtained cured product is reduced, and odor derived from thiol is easily suppressed.
Therefore, with such component (E), the curing speed is extremely fast and the non-wipe property is excellent, while superior storage stability under relatively high temperature conditions (60° C., 30 days) can be obtained.

(3) Blending amount The blending amount of (E) the polyfunctional thiol compound is within the range of 1 to 30 parts by weight based on 100 parts by weight of (A) urethane acrylate oligomer.
The reason for this is that if the amount of the polyfunctional thiol compound is less than 1 weight, the curing speed may be excessively reduced and the non-wipeability may be significantly reduced.
On the other hand, if the amount of the polyfunctional thiol compound exceeds 30 parts by weight, the adhesiveness and durability of the resulting cured film may decrease, and furthermore, it may become more likely to be colored.
Therefore, it is more preferable that the amount of the polyfunctional thiol compound (E) is within the range of 2 to 25 parts by weight, and more preferably 3 to 20 parts by weight, based on 100 parts by weight of the urethane acrylate oligomer (A). It is more preferable to set the value within the range.

Here, with reference to FIG. 1, the relationship between the blending amount of the polymerization inhibitor (F) and the curability and storage stability of the gel nail composition will be explained.
That is, the horizontal axis shows the amount (parts by weight) of the polymerization inhibitor (F) prepared according to Example 1, etc., and the left vertical axis shows the curability evaluation score (relative value). The evaluation points (relative values) of storage stability at 60°C are shown on the right vertical axis.
In addition, the curability evaluation score (relative value) and the storage stability evaluation score (relative value) are the evaluations described in Example 1, respectively: 5 points for ◎, 3 points for ○, 1 point for △, × is given as 0 points.
From the characteristic curve A showing curability in FIG. 1, it is understood that the gel nail composition exhibits good curability when the amount (parts by weight) of the polymerization inhibitor is 5 parts by weight or less. .
Furthermore, from the characteristic curve B showing storage stability, it is understood that the gel nail composition exhibits good storage stability when the amount (parts by weight) of the polymerization inhibitor is 0.01 parts by weight or more. Ru.
Therefore, by setting the blending amount of the polymerization inhibitor (F) to 0.01 to 5 parts by weight, a good balance between curability and storage stability, which are contradictory properties, can be achieved, resulting in a gel with good quality. A nail composition can be obtained.

6. Ingredients (F)
(1) Function The compounding component (F) is a polymerization inhibitor containing (F1) a metal salt of a nitroso compound and/or (F2) a phenol compound. Features.
That is, by using such a polymerization inhibitor, an extremely fast curing speed can be obtained in cooperation with other ingredients without excessively suppressing the function of radicals generated by ultraviolet irradiation.
In addition, with such a polymerization inhibitor, a gel nail composition with excellent long-term storage stability can be obtained not only at room temperature (25°C) but also under relatively high temperature conditions of about 60°C. be able to.

In other words, the single use of conventionally used tocopherol compounds, tert-butylhydroquinone compounds, etc. is still poor in terms of storage stability.
Therefore, when using a tocopherol compound as part of the compounding component (F), the content is preferably less than 1,000 ppm, and more preferably within the range of 5 to 200 ppm. is more preferably a value within the range of 10 to 80 ppm.
Similarly, when a tert-butylhydroquinone compound is used in combination, the content is preferably less than 300 ppm, more preferably 5 to less than 100 ppm. More preferably, the value is less than 20 ppm.

(2) Type The type of metal salt of the nitroso compound is not particularly limited, but may include at least one of aluminum salts of nitroso compounds, iron salts of nitroso compounds, zinc salts of nitroso compounds, and the like.

More specifically, among the metal salts of nitroso compounds, aluminum salts of N-nitroso-N-phenylhydroxylamine, iron salts of N-nitroso-N-phenylhydroxylamine, and iron salts of N-nitroso-N-phenylhydroxylamine are used. It is preferable to use at least one compound selected from the group consisting of zinc salts.
The reason for this is that by blending such a metal salt of a nitroso compound into a composition for gel nails, the storage stability can be easily improved without significantly inhibiting the curability of the composition for gel nails.

Furthermore, among the metal salts of these nitroso compounds, it is particularly preferable to use the aluminum salt of N-nitroso-N-phenylhydroxylamine.
The reason for this is that by incorporating the metal salt of such a nitroso compound into a composition for gel nails, it is possible to achieve both curability and storage stability even in a relatively small amount; This is because it is difficult to generate heat when the composition for use in polymerization is polymerized.

Further, when blending the metal salt of the nitroso compound into the gel nail composition as a polymerization inhibitor, first mix the metal salt of the nitroso compound and (B) the monofunctional (meth)acrylate monomer, and then It is preferable to incorporate it into a gel nail composition.
The reason for this is that by blending in this way, the highly cohesive metal of the nitroso compound can be easily dispersed uniformly in the gel nail composition, which in turn can further improve storage stability. be.

The mixing ratio of the metal salt of the nitroso compound (F1) and the monofunctional (meth)acrylate monomer (B) is not particularly limited as long as the metal salt of the nitroso compound is uniformly dispersed in the gel nail composition, but From the viewpoint of ease of mixing, the ratio (by weight) of (B) monofunctional (meth)acrylate monomer/(F1) nitroso compound metal salt is preferably set to a value within the range of 2 to 10.

Furthermore, the types of phenolic compounds are not particularly limited, but include 4-methoxyphenol, 2,6-di-tert-butyl-4-methylphenol, 2,6-di-tert-butylphenol, 1 , 4-dihydroxybenzene, 4-tert-butylpyrocatechol, 2-tert-butyl-1,4-dihydroxybenzene, 2-tert-butyl-4,6-dimethylphenol, and the like.

More specifically, among the phenol compounds, at least one of 4-methoxyphenol, 2,6-di-tert-butyl-4-methylphenol, and 2,6-di-tert-butylphenol is preferred; Methoxyphenol is more preferred.
The reason for this is that by using such a phenol compound, even in a relatively small amount, the contradictory properties of curability and storage stability of the composition for gel nails can be easily achieved, and furthermore, the composition for gel nails This is because it is difficult to generate heat when polymerized.

(3) Blend amount 1
The content of the polymerization inhibitor (F) is within the range of 0.01 to 5 parts by weight based on 100 parts by weight of the urethane acrylate oligomer (A).
The reason for this is that if the amount of the polymerization inhibitor incorporated is less than 0.01 weight, the storage stability at a relatively high temperature (60° C.) may be significantly reduced.
On the other hand, if the amount of the polymerization inhibitor added exceeds 5 parts by weight, the curing speed may be significantly reduced and the non-wipeability may also be reduced.
Therefore, it is more preferable that the amount of the polymerization inhibitor (F) is in the range of 0.05 to 4 parts by weight, and more preferably 0.1 to 3 parts by weight, based on 100 parts by weight of the urethane acrylate oligomer (A). More preferably, the value is within the range of parts by weight.

(4) Blend amount 2
In addition, when using a combination of (F1) a metal salt of a nitroso compound and (F2) a phenol compound as the polymerization inhibitor of component (F), (F1) a metal salt of a nitroso compound and (F2) a phenol compound. It is preferable to combine them in a predetermined ratio.
More specifically, it is preferable that the ratio (by weight) of (F1) the amount of the metal salt of the nitroso compound blended/(F2) the amount of the phenol compound blended is a value within the range of 0.1 to 10.
The reason for this is that if the ratio of (F1) metal salt of nitroso compound/(F2) phenol compound is less than 0.1, storage stability at relatively high temperatures may be significantly reduced. This is because there is.
On the other hand, if the ratio of the amount of the metal salt of the nitroso compound (F1)/the amount of the phenol compound (F2) exceeds 10, the curing speed may decrease significantly and the non-wipeability may also decrease.
Therefore, it is more preferable to set the ratio of (F1) metal salt of nitroso compound/(F2) phenol compound to a value within the range of 0.2 to 7, and more preferably a value within the range of 0.3 to 4. It is more preferable that

Here, referring to FIG. 2, the relationship between the ratio of (F1) a metal salt of a nitroso compound/(F2) a phenol compound as a polymerization inhibitor, and curability and storage stability will be explained.
That is, the horizontal axis shows the ratio (-) of (F1) the metal salt of the nitroso compound/(F2) the phenol compound, and the left vertical axis shows the curing evaluation score (relative value). The evaluation score (relative value) of storage stability at 60° C. is shown on the right vertical axis.
In addition, the curability evaluation score (relative value) and the storage stability evaluation score (relative value) are the evaluations described in Example 1, respectively: 5 points for ◎, 3 points for ○, 1 point for △, × is given as 0 points.
From the characteristic curve A showing curability in FIG. 2, it is clear that when the gel nail composition is photocured by limiting the ratio of (F1) metal salt of nitroso compound/(F2) phenol compound to a predetermined range. It is understood that it shows good curability.
Furthermore, from characteristic curve B showing storage stability, by limiting the ratio of (F1) metal salt of nitroso compound/(F2) phenol compound to a predetermined range, when the gel nail composition is stored for a long period of time, It is understood that it exhibits good storage stability.
Therefore, by setting the ratio of (F1) a metal salt of a nitroso compound/(F2) a phenol compound as a polymerization inhibitor to 0.1 to 10, a balance between curability and storage stability, which are contradictory properties, can be achieved. The properties of the gel nail compositions are improved, and a gel nail composition of good quality can be obtained.

(5) Blend amount 3
It is preferable to determine the blending amount of (F) the polymerization inhibitor and also the blending amount of (E) the polyfunctional thiol compound.
That is, it is preferable that the ratio (by weight) of (F) the amount of polymerization inhibitor blended/(E) the amount of polyfunctional thiol compound blended is within the range of 0.01 to 0.6.
The reason for this is that if the ratio of (F) polymerization inhibitor content/(E) polyfunctional thiol compound content is less than 0.01, storage stability at relatively high temperatures may be significantly reduced. This is because there is.
On the other hand, if the ratio of the amount of polymerization inhibitor (F)/the amount of polyfunctional thiol compound (E) exceeds 0.6, the curing speed will decrease significantly and the non-wipeability may also decrease. be.
Therefore, it is more preferable to set the ratio of (F) amount of polymerization inhibitor/(E) amount of polyfunctional thiol compound to a value within the range of 0.03 to 0.55, and more preferably 0.07 to 0. More preferably, the value is within the range of .5.

Here, referring to FIG. 3, the relationship between the ratio of (F) polymerization inhibitor/(E) polyfunctional thiol and curability and storage stability will be explained.
That is, the horizontal axis shows (F) the ratio of polymerization inhibitor/(E) polyfunctional thiol (-), and the left vertical axis shows the curability evaluation score (relative value). The evaluation score (relative value) of storage stability at 60° C. is shown on the right vertical axis.
In addition, the evaluation points for curability (relative value) and the evaluation points for storage stability (relative value) are the evaluations described in Example 1, respectively: 5 points for ◎, 3 points for ○, 1 point for △, × is given as 0 points.
From the characteristic curve A showing curability in FIG. 3, by limiting the ratio of (F) polymerization inhibitor/(E) polyfunctional thiol, when the gel nail composition is photocured, good results can be obtained. It is understood that it exhibits curability.
Furthermore, from characteristic curve B showing storage stability, by limiting the ratio of (F) polymerization inhibitor/(E) polyfunctional thiol, gel nail compositions can be stored for a long period of time to have good storage stability. It is understood that it indicates gender.
Therefore, by setting the ratio of (F) polymerization inhibitor/(E) polyfunctional thiol to 0.01 to 0.6, a good balance between curability and storage stability, which are contradictory properties, can be achieved. Thus, a good gel nail composition can be obtained.

(6) Blend amount 4
Further, it is preferable to determine the amount of the polymerization inhibitor (F) in consideration of the amount of the polymerization initiator (D).
That is, it is preferable that the ratio (by weight) of (F) polymerization inhibitor loading/(D) polymerization initiator loading is within the range of 0.01 to 0.3.
The reason for this is that if the ratio of the amount of compounded component (F)/(D) polymerization initiator is less than 0.01, storage stability at relatively high temperatures may be significantly reduced. It is.
On the other hand, if the ratio of the amount of (F) polymerization inhibitor/(D) polymerization initiator exceeds 0.3, the curing speed may decrease significantly and the non-wipeability may also decrease. .
Therefore, it is more preferable to set the ratio of (F) amount of polymerization inhibitor/(D) amount of polymerization initiator to a value within the range of 0.03 to 0.25, more preferably 0.07 to 0. More preferably, the value is within the range of 2.

Here, referring to FIG. 4, the relationship between the ratio of (F) polymerization inhibitor/(D) polymerization initiator and curability and storage stability will be explained. That is, on the horizontal axis, (F) polymerization inhibitor The ratio of / (D) polymerization initiator (-) is taken and shown, the left vertical axis shows the curing evaluation score (relative value), and the right vertical axis shows the storage stability at 60°C. The evaluation score (relative value) of gender is taken and shown.
In addition, the curability evaluation score (relative value) and the storage stability evaluation score (relative value) are the evaluations described in Example 1, respectively: 5 points for ◎, 3 points for ○, 1 point for △, × is given as 0 points.
From the characteristic curve A showing the curability in FIG. It is understood that it exhibits curability.
In addition, from the characteristic curve B showing storage stability, by limiting the ratio of (F) polymerization inhibitor/(D) polymerization initiator, it is possible to achieve good storage stability when the gel nail composition is stored for a long period of time. It is understood that it indicates gender.
Therefore, by setting the ratio of (F) polymerization inhibitor/(D) polymerization initiator to 0.01 to 0.3, a good balance between curability and storage stability, which are contradictory characteristics, can be achieved. Thus, a good gel nail composition can be obtained.

7. Additive (1) Anti-coloring agent In constituting the composition for gel nails, it is preferable to use an anti-coloring agent as a compound different from the polymerization inhibitor.
However, a compound generally used as a polymerization inhibitor may also be referred to as a coloring inhibitor.
That is, by using such a coloring inhibitor, it is possible to obtain a gel nail composition in which yellowing caused by a polymerization inhibitor or thiol is reduced when the gel nail composition is cured.

Here, as a suitable coloring inhibitor, it is preferable to use a coloring inhibitor containing an arylphosphine compound, a silazane compound, or either one of the compounds.
The type of such arylphosphine compound is not particularly limited, but a more specific example is triphenylphosphine.
Further, the type of silazane compound is not particularly limited, but examples include 1,1,3,3-tetramethyldisilazane, 1,1,1,3,3,3-hexamethyldisilazane. At least one of silazane and the like can be mentioned.

Further, when using a coloring inhibitor, the amount thereof is preferably within the range of 0.01 to 3 parts by weight based on 100 parts by weight of the urethane acrylate oligomer (A).
The reason for this is that if the amount of the coloring inhibitor added is less than 0.01 weight, it may not be possible to sufficiently suppress coloring due to the polymerization inhibitor and the like.
On the other hand, if the amount of the coloring inhibitor exceeds 3 parts by weight, the photopolymerization reaction may be inhibited and the curability of the gel nail composition may decrease.
Therefore, it is more preferable that the amount of the coloring inhibitor is in the range of 0.02 to 2.5 parts by weight, and more preferably 0.03 to 2 parts by weight, based on 100 parts by weight of the urethane acrylate oligomer (A). It is more preferable to set the value within the range of .

(2) Fluorescent brightener In constituting the composition for gel nails, the fluorescent brightener is selected from the group consisting of benzophenone compounds, benzotriazole compounds, hydroxyphenyltriazine compounds, and benzoxazolylthiophene compounds. Preferably, at least one compound is used.
The reason for this is that by using such an optical brightener, when a gel nail composition containing the colorant described below is cured, a cured product with excellent color tone and reduced yellowing can be obtained. This is because it can be done.

Here, as a suitable optical brightener, a benzoxazolylthiophene compound can be mentioned, and more specifically, 2,5-bis(5-tert-butyl-2-benzoxazolyl)thiophene can be mentioned.
The amount of the optical brightener to be blended is determined within a range that does not inhibit the photocuring speed or reduce the object of the present invention, and is usually 0.01 parts by weight per 100 parts by weight of (A) urethane acrylate oligomer. It is preferable to use it in a range of 3 parts by weight.

(3) Ultraviolet absorber In constituting the gel nail composition, at least one type of ultraviolet absorber selected from the group consisting of benzophenone compounds, para-aminobenzoic acid (PABA) compounds, cinnamic acid compounds, and salicylic acid compounds is used. Preferably, compounds are used.
The reason for this is that by using such an ultraviolet absorber, the photocuring reaction can be effectively suppressed when the gel nail composition is stored for a long period of time under relatively high temperature conditions, and as a result, storage stability can be improved. This is because it can further increase the hardness and reduce yellowing during curing.
The type of ultraviolet absorber is not particularly limited, but examples include 4-tert-butyl-4'-methoxydibenzoylmethane, oxybenzone, 2,4,6-tris[4-(2- Examples include at least one of the following: ethylhexyloxycarbonyl)anilino]-1,3,5-triazine, diethylaminohydroxybenzoylhexylbenzoate, bisethylhexyloxyphenolmethoxyphenyltriazine, and the like.
The amount of the ultraviolet absorber to be added is determined within a range that does not inhibit the photocuring rate or reduce the object of the present invention, and is usually 0.01 to 10 parts by weight per 100 parts by weight of (A) urethane acrylate oligomer. It is preferable to use within the range of parts by weight.

(4) Surface Conditioning Agent In constituting the composition for gel nails, it is preferable to use a siloxane compound or the like as a surface conditioning agent in the coating film.
The reason for this is that by using these surface conditioning agents in the gel nail composition, it is possible to reduce the unevenness of the surface of the cured film of the gel nail composition and further improve the surface smoothness. be.
Further, the type of siloxane compound is not particularly limited, but examples include polydimethylsiloxane, polymethylalkylsiloxane, polyether-modified polydimethylsiloxane, polyester-modified polydimethylsiloxane, polyether-modified polymethylalkylsiloxane, At least one of polyester-modified polymethylalkylsiloxane, polyether-modified polydimethylsiloxane having an acrylic group, polyester-modified polydimethylsiloxane having an acrylic group, polyether-modified hydroxyl-containing polydimethylsiloxane, polyester-modified hydroxyl-containing polydimethylsiloxane, etc. It will be done.
In addition, the amount of the surface conditioner is determined within a range that does not impair the object of the present invention, and is usually used in the range of 0.01 to 10 parts by weight based on 100 parts by weight of the urethane acrylate oligomer (A). It is preferable.

(5) Silica particles In constituting the composition for gel nails, it is preferable to use silica particles as a viscosity modifier and storage stabilizer.
The reason for this is that by using such silica particles, the viscosity of the gel nail composition can be easily adjusted and a more uniform composition can be obtained, which improves storage stability at relatively high temperatures. It's for a reason.
Further, by using such silica particles, in the gel nail composition containing a pigment described below, it becomes easier to prevent the pigment from settling, and a cured film with a more uniform color tone can be obtained.
Here, such silica particles include, for example, hydrophobic fumed silica, and more specifically, "Aerosil RY200S", "Aerosil RY200", "Aerosil R202", "Aerosil RX200", and "Aerosil RY300". , "Aerosil R805,""AerosilR812," and "Aerosil R972" (all of which are trade names manufactured by Nippon Aerosil Co., Ltd.).
In addition, the amount of silica particles to be blended is determined within a range that does not reduce the transparency of the composition and the cured product of the composition, and is usually based on the total amount (100% by weight) containing components (A) to (F). , preferably within the range of 1 to 3% by weight.

(6) Coloring agent In constituting the composition for gel nails, it is preferable to add an inorganic coloring pigment, an organic coloring pigment, an organic coloring agent, a pearl pigment, a glitter coloring agent, etc. as a coloring agent.
That is, preferred pigments include organic coloring pigments such as condensed azo pigments, diketopyrrolopyrrole pigments, perylene pigments, quinacridone pigments, isoindolinone pigments, dioxazine pigments, and phthalocyanine pigments, and titanium pigments. At least one of inorganic coloring pigments such as carbon black pigments can be used.
Examples of the pearl pigment include at least one of natural pearls such as fish scale foil, and synthetic pearl pigments such as metal oxide-coated mica, bismuth acid chloride, and basic lead carbonate.
Examples of the glitter coloring agent include at least one of a polyethylene terephthalate film, which is a synthetic resin film having fine grooves, a vapor-deposited metal, and a binder resin, such as an epoxy resin, laminated and cut into pieces.
The amount of the pigment to be blended is determined within a range that does not inhibit the photocuring speed or reduce the object of the present invention, and is usually 0.1 to 30 parts by weight based on 100 parts by weight of (A) urethane acrylate oligomer. used within the range.

(7) Organic solvent In addition, when forming the photocurable gel nail composition, the photocurable gel nail composition may further contain an organic solvent for the purpose of viscosity adjustment, uniform mixing, etc. The amount is preferably within the range of 0.01 to 30 parts by weight based on 100 parts by weight of (A) urethane acrylate resin.
The reason for this is that by blending the organic solvent in this way, the ingredients of the photocurable gel nail composition can be mixed more uniformly and the viscosity can be adjusted to a suitable range, so it is possible to This is because it is possible to improve the ease of handling when applying to.
Therefore, when blending an organic solvent, it is more preferable to set the blending amount to a value within the range of 0.1 to 20 parts by weight, and 1 to 10 parts by weight, based on 100 parts by weight of (A) urethane acrylate resin. It is more preferable to set the value within the range of 1.

Regarding the type of organic solvent, it is preferable that it is at least one selected from the group selected from ethyl acetate, propyl acetate, butyl acetate, and isobutyl acetate.
If this type is used, it is possible to suppress odor and irritation to nails, etc. caused by the combination of organic solvents, and further improve safety in the use of photocurable gel nail compositions. Can be done.

(8) Other additives Also, in gel nail compositions, dispersants, antifoaming agents, pigment wetting agents, dispersants, flow regulators, thermal polymerization inhibitors are added for the purpose of adjusting viscosity and application suitability. , oxidative polymerization inhibitor, etc. may be added.

8. Viscosity The viscosity (initial viscosity) of the gel nail composition can be changed by appropriately adjusting the monomer type, additive type, and their blending amount depending on the purpose of use. Usually, it is preferable that the viscosity is within the range of 3,000 to 100,000 mPa·s at a measurement temperature of 25°C.
The reason for this is that by setting the viscosity within a specified range, not only is it easier to handle, but even if the viscosity has increased slightly during storage, a uniform coating film is formed and a good coating is formed. This is because a cured film having a good appearance can be obtained.
Therefore, it is more preferable to set the viscosity of the gel nail composition to a value within the range of 4,000 to 80,000 mPa·s, and more preferably to a value within the range of 5,000 to 60,000 mPa·s. .

Further, it is preferable that the gel nail composition exhibits a small increase in viscosity before and after storage.
More specifically, when stored at 60° C. for 30 days, it is preferable that the increase rate from the initial viscosity is 100% or less.
The reason for this is that gel nail compositions with such a small increase in viscosity can be easily applied to the base material (nails) even after long-term storage. This is because it can be done.
Therefore, the rate of increase in viscosity from the initial viscosity when stored at 60° C. for 30 days is more preferably 75% or less, and even more preferably 50% or less.

Here, referring to FIG. 5, the relationship between the elapsed time and the rate of increase in viscosity when the gel nail composition is stored at 60° C. will be explained.
That is, in FIG. 5, the horizontal axis shows elapsed time (days), and the vertical axis shows the rate of increase in viscosity from the initial viscosity.
From the characteristic curves A and B in FIG. 5, it can be seen that the gel nail composition of the present invention has a viscosity increase rate of 100% or less after 30 days at 60°C, and has good performance when stored for a long period of time. It is understood that it exhibits excellent storage stability.
On the other hand, from the characteristic curves C and D, it is understood that gel nail compositions that do not satisfy the constitution of the present invention have an increase rate of 300% or more after a certain period of time and do not exhibit good storage stability.
In addition, in characteristic curves C and D, gelation progresses after a certain period of time, making it difficult to measure the viscosity, and Figure 5 shows the rate of increase in viscosity during the period during which measurement was possible. There is.
Therefore, as compounding components, the urethane acrylate resin contains predetermined amounts of monofunctional and polyfunctional (meth)acrylate monomers, a photopolymerization initiator, a predetermined polyfunctional thiol compound, and a predetermined polymerization inhibitor. By preparing the composition for gel nails, it is possible to obtain a composition for gel nails that exhibits good storage stability when stored for a long period of time.

9. Application (1) Gel Nail One of the applications of the photocurable gel nail composition of the present invention is to use it in a gel nail method as shown in the second embodiment described below.
By using such a photocurable gel nail composition, a user can efficiently obtain a cured film with excellent non-wipeability.
A gel nail method using the photocurable gel nail composition of the present invention will be described in detail in the second embodiment described below.

(2) Gel Nail Seal Further, one of the further uses of the photocurable gel nail composition of the present invention is a gel nail seal using the photocurable gel nail composition.
Specifically, as shown in FIG. 6(a), the gel nail sticker includes an adhesive layer 28 formed on a release sheet 26, and a base layer 30 made of synthetic resin formed on the adhesive layer 28. , a gel nail seal 24 including a cured film layer 32 derived from the photocurable gel nail composition of the first embodiment, formed on a base layer 30 on the opposite side to the adhesive layer 28.

Therefore, by pasting such a gel nail sticker, it is possible to easily decorate the nail without applying gel nail directly to the nail.
Furthermore, when replacing the gel nail seal, it can be easily removed by peeling off the gel nail seal without using organic solvents or the like.

The release sheet 26 used in the gel nail seal 24 includes a main body sheet 26a made of a well-known synthetic resin such as polyethylene terephthalate film (PET film), polyethylene, vinyl chloride, etc., and a release sheet 26 formed on at least one surface of the main body sheet 26a. The mold release layer 26b can be composed of at least the mold release layer 26b.
The mold release layer 26b is preferably formed by applying a silicone mold release agent, but fluororesin, natural wax, polyethylene or polypropylene wax, higher fatty acids or higher fatty acid esters, metal salts thereof, etc. may also be used. .
Further, the thickness of the release sheet is not particularly limited, but it is usually preferably 0.5 to 1.2 mm.

The adhesive layer 28 provided on the release sheet 26 is for adhering the gel nail sticker 24 peeled off from the release sheet 26 to the user's nail, and is made of, for example, a synthetic resin such as acrylic and ethyl acetate. A well-known pressure-sensitive adhesive (adhesive) mixed with an organic solvent such as acetone or the like can be used.
Further, the base layer 30 provided on the adhesive layer 28 serves as a base for the cured film layer 32, and can be made of a well-known synthetic resin such as an acrylic resin, a urethane resin, or a vinyl acetate resin. Further, the base layer 30 is preferably formed of a soft material having a certain degree of flexibility.
Further, the thickness of the underlayer is not particularly limited, but it is usually preferably 10 to 500 μm.
Note that the base layer 30 may be transparent, or may be colored by mixing a predetermined pigment into a resin, or may contain glitter or the like as necessary.

Further, the cured film layer in the gel nail seal can be regarded as the same as the cured film layer formed by curing the composition for gel nails of the present invention.
Therefore, the gel nail composition can be cured by the same method as the photocuring step of the second embodiment described below.
Further, the thickness of the cured film layer is not particularly limited, but it is usually preferably a value within the range of 10 μm to 5 mm, more preferably a value within the range of 20 μm to 2 mm, More preferably, the value is within the range of 30 μm to 0.5 mm.

Further, the gel nail seal 24 may include a decorative layer 34 between the base layer 30 made of synthetic resin and the cured film layer 32, as shown in FIG. 6(b).
Furthermore, the gel nail seal 24 may have a protective layer 36 on the cured film layer 32, as shown in FIG. 6(b).
In this way, by using a gel nail seal that has a decorative layer and/or a protective layer, superior decoration can be applied to the nail more easily than by applying gel nail to the nail. be able to.

(3) Gel Nail Chip Another application of the photocurable gel nail composition of the present invention is a gel nail chip 38 as shown in FIGS. 6(c) and 6(d).

Specifically, as shown in FIG. 6(c), the gel nail tip 38 is similar to the gel nail seal described above except that it does not include the release sheet 26 and the adhesive layer 28 provided on the release sheet 26. The composition is as follows.
The user attaches an adhesive (adhesive) such as double-sided tape, a sticker, or an adhesive gummy to the side of the base layer 30 on which the cured film layer 32 is not formed, thereby attaching the nail to the gel nail tip. Can be pasted together.
In addition, users can easily remove the nail tip from the nail after use by soaking the nail in hot water or using a remover, and by handling it properly, the nail tip can be used repeatedly. It is.

Further, as shown in FIG. 6(d), the gel nail tip 38 may have a decorative layer 34 and/or a protective layer 36, similarly to a gel nail seal.
In this way, by providing a gel nail tip with a decorative layer and/or a protective layer, more excellent decoration can be applied to the nail.

[Second embodiment]
A second embodiment of the present invention is a gel nail method using any one of the photocurable gel nail compositions described above in the first embodiment, comprising the following steps (1) to (4). A gel nail method comprising:
(1) Step of preparing a composition for gel nails (2) Step of applying the composition for gel nails and forming a coating layer (3) Step of photocuring the coating layer to form a cured film (4) After use Process of peeling off the cured film of

1. Preparation Step As shown in FIG. 7(a), a base material 10, which is the nail of a finger 10', is prepared as a base material on which a gel nail layer is to be formed.
At that time, if the surface of the base material 10 of the finger 10' is dirty, it is preferable to degrease it with alcohol or the like in advance.
Further, the base material on which the coating layer is formed is usually a natural nail, but it may also be a synthetic plastic base material such as ABS or acrylic sheet.
That is, by forming a gel nail layer using the gel nail composition of the present invention using a synthetic plastic base material such as an ABS sheet, it is also possible to construct an artificial nail or a false nail. .

On the other hand, a gel nail composition according to the first embodiment is prepared. That is, such a gel nail composition can be prepared by a known mixing method. For example, a composition for gel nails can be prepared by uniformly mixing the ingredients using various mixing devices such as a propeller mixer, a planetary mixer, a ball mill, a jet mill, a three-roller, and a kneader.

2. Application Step Next, as shown in FIG. 7(b), the gel nail composition 12' is applied onto the base material (nail) 10.
Here, the method of applying the gel nail composition to the base material (nail) is not particularly limited either, but for example, a brush, brush, spatula, roller, dropper, etc. can be used.
Although the thickness of the coating layer depends on the design, it is generally preferable to set the value within the range of 50 μm to 2 mm, more preferably the value within the range of 30 μm to 3 mm, and the thickness of the coating layer is preferably within the range of 10 μm to 5 mm. It is more preferable to set the value within the range.

3. Photo-curing step Next, as shown in FIG. 7(c) etc., the gel nail composition 12' is irradiated with a predetermined amount of radiation (ultraviolet light) 14a from the irradiation device 14 to be photo-cured to a predetermined degree. A gel nail layer 12 is formed on the base material (nail) 10.
As shown in FIG. 8(d), when forming gel nail layers 20, 20' having a multilayer structure, the base material 10 shown in FIG. 8(a) is repeatedly subjected to a coating process and a photocuring process. Just repeat the process.

Here, when forming a gel nail layer from one coating layer, it is preferable to set the irradiation amount to a value within the range of 300 to 800 mJ/cm ² .
On the other hand, when forming a multilayer structure, for example, a gel nail layer 20' having a multilayer structure from two gel nail layers 12 and 16 as shown in FIG. It is preferable to set the ^second irradiation amount to a value within the range of 300 to 800 mJ/cm ² .

Further, as shown in FIG. 8(d), when forming a multilayered gel nail layer 20 from three gel nail layers 12, 16, and 18, the first irradiation amount is within the range of 100 to 500 mJ/cm ² It is preferable that the second irradiation amount be a value within the range of 120 to 600 mJ/cm ² and the third irradiation amount be a value within the range of 150 to 800 mJ/cm ² .
That is, it is preferable to apply the same amount of irradiation to each layer regardless of the number of coated layers.

As shown in FIGS. 8(a) to 8(d), when forming a gel nail layer 20 with a multilayer structure, for example, a combination of a base layer, an intermediate layer, and a protective layer, a base layer, a decorative layer, a decorative layer, etc. It is also preferred to consist of a combination of layers.
More specifically, when forming a gel nail layer 20 with a multilayer structure consisting of a combination of a base layer, an intermediate layer, and a protective layer, a clear gel nail composition is applied to the base material 10 and then exposed to ultraviolet rays. By irradiation, a clear base layer 12 with a thickness of 100 to 1,000 μm is formed as the first gel nail layer.

Next, after applying a colored gel nail composition on the clear base layer 12 that is the first gel nail layer, a predetermined amount of ultraviolet rays is further applied to the clear base layer 12, which is the second gel nail layer. A color intermediate layer 16 having a thickness of 100 to 1,000 μm is formed.
Furthermore, after applying the clear or colored non-wipe type gel nail composition of the present invention onto the colored intermediate layer 16, which is the second gel nail layer, a predetermined amount of ultraviolet rays is irradiated, and a third layer is formed. A clear protective layer 18 having a thickness of 100 to 1,000 μm is formed as a gel nail layer.

Therefore, in the gel nail layer 20 having a multilayer structure, the base layer 12 provides excellent adhesion to the nail, which is the base material 10, and the color intermediate layer 16 provides excellent decorative properties. Layer 18 can further enhance the durability of color intermediate layer 16 and the like.

4. Peeling Process Also, the peeling process is a process of peeling the formed gel nail layer 20 from the nail after use.
More specifically, the gel nail layer 20 is scratched by rubbing with a file (nail file).
Next, cotton soaked in acetone is placed on the gel nail layer, wrapped in aluminum foil or the like to prevent volatilization, and left as is for an appropriate period of time (for example, 10 minutes). As a result, the cured gel nail layer swells and is partially peeled off from the base material (nail) 10.
Furthermore, the gel nail layer 20 remaining on the base material (nail) 10 can be completely peeled off from the base material (nail) 10 using a stick-like tool or the like.

Hereinafter, the present invention will be explained in detail based on Examples, but the present invention is not limited to these Examples without particular reason.

[Example 1]
1. Preparation of composition for gel nails In a container, the following ingredients (A) to (G) are mixed in the proportions shown in Table 1, and then mixed using a stirring device until uniform. A composition for nails was prepared.

(A) Urethane acrylate resin a1: Polyester skeleton urethane acrylate resin (2-3 functional, Mw 3,500, Tg 52°C)
a2: Polyester skeleton urethane acrylate resin (bifunctional, Mw 18,000, Tg -39°C)
a3: Polyether skeleton urethane acrylate resin (bifunctional, Mw60,000, Tg-6°C)

(B) Monofunctional (meth)acrylate monomer b1: Acryloylmorpholine b2: Isobornyl methacrylate b3: Ethyl methacrylate b4: 2-hydroxyethyl methacrylate

(C) Polyfunctional (meth)acrylate monomer c1: Trimethylolpropane triacrylate (trifunctional acrylate monomer)
c2: EO 3.8 mole adduct diacrylate of bisphenol A (bifunctional acrylate monomer)
c3: Dipentaerythritol hexaacrylate (6-functional acrylate monomer)
c4: Pentaerythritol triacrylate (trifunctional acrylate monomer)

(D) Photopolymerization initiator, etc. d1: 1-Hydroxy-cyclohexyl-phenyl-ketone d2: 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide d3: 2-hydroxy-2-methylpropiophenone d4: Jujo Curing accelerator JAR-8 manufactured by Chemical Company

(E) Polyfunctional thiol compound e1: Pentaerythritol tetrakis (3-mercaptobutyrate)
e2: 1,4-bis(3-mercaptobutyryloxy)butane e3: 1,3,5-tris(3-mercaptobutyloxyethyl)-1,3,5-triazine-2,4,6(1H, 3H,5H)-trione e4: Pentaerythritol tetrakis (3-mercaptopropionate)

(F) Polymerization inhibitor f1: Nitrosophenylhydroxylamine aluminum salt f2: Nitrosophenylhydroxylamine iron salt f3: Nitrosophenylhydroxylamine zinc salt f4: 4-methoxyphenol f5: 2,6-di-tert-butyl-4- Methylphenol f6: tert-butylhydroquinone f7: tocopherol

(G) Additive g1: Polyether-modified polydimethylsiloxane (manufactured by BYK Chemie Japan Co., Ltd., trade name "BYK333")
g2: Hydrophobic fumed silica (manufactured by Nippon Aerosil Co., Ltd., trade name "Aerosil RY200S")
g3: Triphenylphosphine g4: 1,1,3,3-tetramethyldisilazane g5: 1,1,1,3,3,3-hexamethyldisilazane g6: 2,5-bis(5-tert- Butyl-2-benzoxazolyl)thiophene g7: 4-tert-butyl-4'-methoxydibenzoylmethane g8: Perylene-based red pigment Pigment Red149
g9: Phthalocyanine-based blue pigment PigmentBlue15

2. Evaluation of compositions for gel nails (1) Evaluation of handling properties The initial viscosity of the composition for gel nails was measured at 25°C using an E-type viscometer (Tokimec Co., Ltd. Digital Viscometer DVM-E2 model). , evaluated in light of the following criteria.
◎: The viscosity was 3,000 to 100,000 mPa·s.
○: The viscosity was 1000 to less than 3,000 mPa·s, or more than 100,000 to 300,000 mPa·s.
Δ: The viscosity was 500 to less than 1000 mPa·s, or more than 300,000 to 500,000 mPa·s.
×: Viscosity was less than 500 mPa·s or more than 500,000 mPa·s, or viscosity measurement was impossible due to gelation.

(2) Photocurability evaluation After screen printing the gel nail composition to a thickness of 50 μm on a 100 μm PET film as a base material under the following conditions, the gel nail composition was cured as described below using a UV device dedicated to gel nails. The gel nail composition was photocured under the following conditions to evaluate the photocurability of the gel nail composition.
That is, it was photocured using a UV device exclusively for gel nails under the curing conditions of a hybrid LED light (manufactured by Jujo Chemical Co., Ltd., SOFIRAH, 36W, 365 nm, 405 nm, irradiation time: 15 seconds).
Next, the obtained cured film was subjected to a grid test measured in accordance with JIS K 5600, and the photocurability of the gel nail composition was evaluated in accordance with the following criteria.
◎: The number of peelings in a grid pattern was 0 to 5 pieces/100 pieces.
○: The number of peelings in a grid pattern was 6 to 10 pieces/100 pieces.
Δ: The number of peelings in a grid pattern was 11 to 30 pieces/100 pieces.
x: The number of peelings in a grid pattern was 31 or more/100 pieces.

(3) Non-wipeability Similar to the photo-curing property evaluation, using a UV device dedicated to gel nails, the curing conditions were set using a hybrid LED light (manufactured by Jujo Chemical Co., Ltd., SOFIRAH, 36W, 365nm, 405nm, irradiation time: 15 seconds). The gel nail composition was then photocured to evaluate the non-wipeability of the gel nail composition.
That is, the resulting cured film was subjected to a finger touch test for tack, and the non-wipeability of the gel nail composition was evaluated in accordance with the following criteria.
(Coating conditions)
Viscosity: Approximately 8,000 mPa・s (measurement temperature: 25°C)
Brush: Brush for gel nails Cured film thickness: Approx. 0.1-1mm
(Curing conditions)
Irradiation device: Hybrid LED light (manufactured by Jujo Chemical Co., Ltd., SOFIRAH, 36W, 365nm, 405nm, irradiation time: 15 seconds, 20 seconds)
◎: Almost tackleless was obtained not only with an irradiation time of 20 seconds but also with an irradiation time of 15 seconds.
Good: When the irradiation time was 15 seconds, a tacky feeling remained, but when the irradiation time was 20 seconds, it became almost tackless.
Δ: Considerable tackiness remains when the irradiation time is 15 seconds, and a slight tackiness remains even when the irradiation time is 20 seconds.
×: A noticeable tackiness remains even when the irradiation time is 20 seconds as well as when the irradiation time is 15 seconds.

(4) Adhesion The cured film obtained under the conditions of irradiation time of 15 seconds was evaluated for adhesion by performing a nail scratch test. That is, the obtained cured film was scratched 30 times with a fingernail, and the adhesion was evaluated based on the change in appearance of the cured film based on the following criteria.
◎: No change in appearance.
○: Some peeling is observed in the appearance.
Δ: Some peeling and some whitening are observed in the appearance.
×: Large whitening in appearance and peeling observed throughout.

(5) Yellowing Yellowing of the cured film obtained under the conditions of irradiation time of 15 seconds, prepared for the evaluation of photocurability, was visually evaluated in accordance with the following criteria.
◎: Colorless and transparent in appearance, with no signs of yellowing observed.
○: A slight change to pale yellow is observed in appearance.
Δ: A change to pale yellow is observed in appearance.
x: A noticeable change to yellow is observed in appearance.

(6) Storage stability 1 (40℃)
The initial viscosity of the gel nail composition was measured at room temperature (25° C.) using an E-type viscometer (Tokimec Co., Ltd. Digital Viscometer Model DVM-E2).
Next, 20 g of the measured gel nail composition was placed inside an ultraviolet light shielding container and left at 40° C. for 30 days.
Next, the viscosity of the gel nail composition after being left was measured, and the storage stability was evaluated based on the change in the initial viscosity measurement based on the following criteria.
◎: The rate of increase in viscosity was 50% or less.
Good: The rate of increase in viscosity was 100% or less.
Δ: The rate of increase in viscosity was 300% or less.
×: The rate of increase in viscosity exceeded 300%, or viscosity measurement was impossible due to gelation.

(7) Storage stability 2 (60℃)
The initial viscosity of the gel nail composition was measured at room temperature (25° C.) using an E-type viscometer (Tokimec Co., Ltd. Digital Viscometer Model DVM-E2).
Next, 20 g of the measured gel nail composition was placed inside an ultraviolet light shielding container and left at 60° C. for 30 days.
Next, the viscosity of the gel nail composition after being left was measured, and the storage stability was evaluated based on the change in the initial viscosity measurement based on the following criteria.
◎: The rate of increase in viscosity was 50% or less.
Good: The rate of increase in viscosity was 100% or less.
Δ: The rate of increase in viscosity was 300% or less.
×: The rate of increase in viscosity exceeded 300%, or viscosity measurement was impossible due to gelation.

(8) Odor The odor of the gel nail composition was evaluated according to the following criteria.
◎: Almost no irritating odor due to the ingredients contained.
○: Slightly irritating odor due to the blended ingredients is felt.
△: Slightly irritating odor due to the blended ingredients is felt.
×: A noticeable irritating odor due to the ingredients is felt.

[Examples 2 to 7 and Comparative Examples 1 to 2]
As shown in Table 1, gel nail compositions were evaluated in the same manner as in Example 1, except that the type of urethane acrylate resin and the type and amount of the monofunctional (meth)acrylate monomer compound were changed.

[Examples 8 to 13 and Comparative Examples 3 to 4]
As shown in Table 2, gel nail compositions were evaluated in the same manner as in Example 1, except that the type and blending amount of the polyfunctional (meth)acrylate monomer compound were changed.

[Examples 14 to 19 and Comparative Examples 5 to 6]
As shown in Table 3, gel nail compositions were evaluated in the same manner as in Example 1, except that the type and blending ratio of the photopolymerization initiator were changed.

[Examples 20 to 25 and Comparative Examples 7 to 8]
As shown in Table 4, gel nail compositions were evaluated in the same manner as in Example 1, except that the type and amount of the polyfunctional thiol compound were changed.

[Examples 26 to 31 and Comparative Examples 9 to 10]
As shown in Table 5, gel nail compositions were evaluated in the same manner as in Example 1, except that the types and amounts of the photopolymerization initiator and polymerization inhibitor were changed.

[Examples 32 to 38 and Comparative Examples 11 to 13]
As shown in Table 6, gel nail compositions were evaluated in the same manner as in Example 1, except that the types and amounts of the polymerization inhibitor and additives were changed.

[Examples 39 to 44 and Comparative Examples 14 to 15]
In Examples 39 to 44 and Comparative Examples 14 to 15, the photocurable gel nail compositions of Examples 1 to 6 and Comparative Examples 1 to 2 were applied onto an adhesive-coated PET film having a thickness of 100 μm, respectively. A gel nail seal before curing was prepared by applying the gel to a thickness of 40 μm after curing.
Next, a pre-hardened gel nail sticker was applied to a predetermined location on the finger.
Next, in the same manner as in Example 1, the gel nail seal was irradiated with ultraviolet rays to cure the gel nail seal, and the excess gel nail seal was cut off to obtain the final form of the gel nail seal.
In addition, in the same way as Example 1 and Comparative Example 1, the handleability, photocurability, adhesion, yellowing, and storage stability of the photocurable gel nail composition used were evaluated. The results were similar to those of No. 1 and Comparative Example No. 1.

According to the gel nail composition of the present invention, a predetermined urethane acrylate resin, a monofunctional (meth)acrylate monomer, a polyfunctional (meth)acrylate monomer, a photopolymerization initiator, a predetermined polymerization inhibitor, By blending a predetermined amount of It has now become possible to obtain a gel nail composition with excellent storage stability and a gel nail method using the same.
Therefore, the composition for gel nails of the present invention and the gel nail method using the same can be suitably used not only for natural nails but also for artificial nails and false nails.

10: Base material (claw)
10': Finger 12: First gel nail layer (base layer)
12': Application layer of gel nail composition 14: Light irradiation device 14a: Radiation (ultraviolet light)
16: Second gel nail layer (middle layer)
18: Third gel nail layer (protective layer)
20: Gel nail layer with multilayer structure (3 layers) 20': Gel nail layer with multilayer structure (2 layers) 24: Gel nail seal 26: Release sheet 28: Adhesive layer 30: Base layer 32: Cured film layer 34: Decorative layer 36: Protective layer 38: Gel nail tip

Claims (8)

A photocurable gel nail composition characterized by containing the following components (A) to (F) as compounded components.
(A) Urethane acrylate resin 100 parts by weight (B) Monofunctional (meth)acrylate monomer 1 to 30 parts by weight (C) Multifunctional (meth)acrylate monomer 20 to 120 parts by weight (D) Photopolymerization initiator 1 to 30 parts by weight Part (E) Polyfunctional thiol compound containing two or more thiol groups in one molecule
1 to 30 parts by weight (F) 0.01 to 5 parts by weight of a polymerization inhibitor containing a metal salt of a nitroso compound and/or a phenol compound The ratio (weight basis) of the amount of the polymerization inhibitor as the component (F)/the amount of the polyfunctional thiol compound as the component (E) is within the range of 0.01 to 0.6. The photocurable gel nail composition according to claim 1, characterized in that: 3. The photocurable gel nail composition according to claim 1, wherein the metal salt of the nitroso compound is a metal salt of N-nitroso-N-phenylhydroxylamine. The photocurable gel nail composition according to claim 1 or 2, wherein the phenol compound is 4-methoxyphenol. The photocurable gel nail product according to claim 1 or 2, wherein the urethane acrylate resin (A) contains at least a urethane acrylate resin (a1) having a weight average molecular weight in the range of 500 to 3,0000. Composition. A claim characterized in that the monofunctional (meth)acrylate monomer (B) is at least one member selected from the group consisting of (meth)acryloylmorpholine, ethyl (meth)acrylate, and 2-hydroxyethyl (meth)acrylate. Item 2. The photocurable gel nail composition according to item 1 or 2. 3. For photocurable gel nails according to claim 1 or 2, wherein the (E) polyfunctional thiol compound containing two or more thiol groups in one molecule is a polyfunctional secondary thiol compound. Composition. A gel nail method using the photocurable gel nail composition according to any one of claims 1 to 7, comprising the following steps (1) to (4). Method.
(1) Step of preparing a photocurable gel nail composition (2) Applying a photocurable gel nail composition to form a coating layer (3) Photocuring the coating layer to form a cured film Step (4) Step of peeling off the cured film after use

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