Artificial nail composition

Abstract

The present invention provides an artificial nail composition that obtains adhesiveness without using an acid component and exhibits excellent removability by solvent. This artificial nail composition is characterized by including a urethane (meth)acrylate (A component), a hydroxyl group-containing (meth)acrylate (B component), and a photopolymerization initiator (C component), wherein the urethane (meth)acrylate (A component) includes a structure derived from a polyester polyol (a-1) that is liquid at 20°C, an isocyanate (a-2), a hydroxy(meth)acrylate (a-3), and a diol (a-4) that has a branch and is liquid at 20°C, and the urethane (meth)acrylate (A component) content is 38-75 wt% relative to the total amount of the constituent components of the artificial nail composition.

Description

artificial nail composition

[0001] The present invention relates to artificial nail compositions.

[0002] In recent years, photocurable artificial nail compositions known as gel nails have been attracting attention. These artificial nail compositions are used to strengthen and decorate natural nails. The artificial nail composition contains, for example, a urethane acrylate oligomer and an acrylic monomer. After application to the nail, the artificial nail composition is irradiated with, for example, ultraviolet light. The compounds contained in the artificial nail composition are crosslinked by a radical polymerization reaction. As a result, an artificial nail coating is formed.

[0003] In addition, there is a need for an artificial nail composition that adheres well to the nail (natural nail) and prevents peeling. In other words, there is a need for an artificial nail composition that has a high adhesive strength to the nail. In particular, the base gel that is applied to the nail first (as the bottom layer) is required to have good adhesion. For example, Patent Document 1 proposes an artificial nail composition that contains a compound having at least one radically polymerizable unsaturated double bond in the molecule, an acidic phosphorus compound having at least one radically polymerizable unsaturated double bond in the molecule, and a radical polymerization initiator, for the purpose of improving the adhesive strength between the nail and the artificial nail and suppressing peeling or detachment (see, for example, Patent Document 1).

[0004] JP 2010-53097 A

[0005] As described in Patent Document 1, the use of an acid component such as an acidic phosphorus compound can improve adhesion between the nail and the artificial nail composition. However, the use of an acid component can have an adverse effect on the nail, for example, by bonding the acid component with nail proteins. As a result, the nail may be damaged. The present invention aims to solve the above problems and provides an artificial nail composition that has adhesion without using an acid component and is easily removable with a solvent.

[0006] The artificial nail composition of the present invention comprises a urethane (meth)acrylate (component A), a (meth)acrylate having a hydroxyl group (component B), and a photopolymerization initiator (component C), wherein the urethane (meth)acrylate (component A) comprises a structure derived from a polyester polyol (a-1) that is liquid at 20°C, an isocyanate (a-2), a hydroxy (meth)acrylate (a-3), and a branched diol (a-4) that is liquid at 20°C, and wherein the content of the urethane (meth)acrylate (component A) is 38% by weight or more and 75% by weight or less based on the total amount of the components constituting the artificial nail composition.

[0007] According to the present invention, it is possible to provide an artificial nail composition that has adhesion without using an acid component and is easily removable with a solvent.

[0008] Conventionally, artificial nail compositions have been made to adhere well to natural nails by using acidic components such as acrylic acid, methacrylic acid, and phosphoric acid compounds. However, the use of acidic components inevitably affects the nails. The inventors of the present application have discovered an artificial nail composition that has excellent adhesion to natural nails (good adhesion, resistance to peeling, and resistance to lifting) and does not peel off for a long time without using the acidic component by using a urethane (meth)acrylate (component A) described below. Generally, artificial nail compositions that adhere well tend to be resistant to peeling, but they have been able to obtain an artificial nail composition that even has excellent solvent removability.

[0009] <Constituents of Artificial Nail Composition> The artificial nail composition of the present invention contains at least a urethane (meth)acrylate (component A), a (meth)acrylate having a hydroxyl group (component B), and a photopolymerization initiator (component C). The urethane (meth)acrylate (component A) contains a structure derived from a polyester polyol (a-1) that is liquid at 20°C, an isocyanate (a-2), a hydroxy (meth)acrylate (a-3), and a branched diol (a-4) that is liquid at 20°C. The content of the urethane (meth)acrylate (component A) is 38% by weight or more and 75% by weight or less of the total amount of the constituent components of the artificial nail composition.

[0010] The urethane (meth)acrylate (component A) contains a polyester polyol (a-1) that is liquid at 20°C and a branched diol (a-4) that is liquid at 20°C. Therefore, the molecules of component A tend to become irregularly entangled and easily get caught on the nail surface. This allows for an artificial nail composition with high adhesion to be obtained without using an acid component.

[0011] Here, the molar ratio of the diol (a-4) to the polyester polyol (a-1) is preferably in the range of 0.25 or more and 5 or less.

[0012] This allows for the production of an artificial nail composition with high adhesion without the use of an acid component. Furthermore, by ensuring that the molar ratio is within the above range, it is easy to obtain an artificial nail composition that combines hardness and flexibility. Such an artificial nail composition can be filled in.

[0013] The polyester polyol (a-1) is preferably a polyester polyol having a number average molecular weight in the range of 1,000 to 3,000.

[0014] This allows for the production of an artificial nail composition with high adhesion without the use of an acid component. Furthermore, when the number-average molecular weight of the polyester polyol (a-1) that is liquid at 20°C is within the above range, an artificial nail composition that combines hardness and flexibility is easily obtained. Furthermore, the alkyl chain contained in the polyester polyol (a-1) having a number-average molecular weight within the above range is expected to provide water resistance.

[0015] The R value of the urethane (meth)acrylate (component A) is preferably in the range of 1.25 or more and 2.0 or less.

[0016] This allows for an artificial nail composition with high adhesion without using an acid component. Furthermore, when the R value (number of isocyanate groups / number of hydroxyl groups) is within the above range, an artificial nail composition with high leveling properties is easily obtained.

[0017] The molecular weight of the diol (a-4) is preferably 300 or less.

[0018] This allows an artificial nail composition with high adhesion to be obtained without using an acid component. Furthermore, when the molecular weight of the diol (a-4) is 300 or less, the branch density in the urethane (meth)acrylate (component A) can be easily increased. As a result, an artificial nail composition with high adhesion to the nail can be easily obtained.

[0019] Furthermore, when the urethane (meth)acrylate (component A) is taken as 100 parts, the (meth)acrylate (component B) is preferably 30 parts or more and 150 parts or less. By adjusting the amount of the (meth)acrylate (component B) added as a reactive diluent, a jar-type artificial nail composition with high viscosity or a polish-type artificial nail composition with low viscosity can be obtained.

[0020] In this specification, "urethane (meth)acrylate" means one or both of urethane acrylate and urethane methacrylate. "hydroxy (meth)acrylate" means one or both of hydroxy acrylate and hydroxy methacrylate. "(meth)acrylate" means one or both of acrylate and methacrylate.

[0021] Each of the above components will be described in detail below.

[0022] (1) Urethane (meth)acrylate (Component A) In the present invention, the urethane (meth)acrylate (Component A) contains a structure derived from a polyester polyol (a-1), which is liquid at 20°C, an isocyanate (a-2), a hydroxy(meth)acrylate (a-3), and a branched diol (a-4), which is liquid at 20°C.

[0023] (1-1) Polyester Polyol (a-1) The polyester polyol (a-1) is liquid at 20°C (near room temperature). Being liquid at 20°C allows for handling at low temperatures near room temperature. The polyester polyol (a-1) is preferably a polyester polyol having a number-average molecular weight in the range of 1,000 to 3,000. Furthermore, it is preferably an amorphous polyester polyol. Longer alkyl chain lengths are expected to improve water resistance. The number-average molecular weight is more preferably 1,500 to 2,000. For example, it is preferable to include a polyester polyol having a linear chain of C6 or more or a polyol having a branched structure as a structural unit. Furthermore, a polyester polyol having a hydroxyl value of approximately 30 to 120 and an acid value of 0.5 or less can be suitably used. From the viewpoint of handleability, it is preferable that the viscosity at 30°C is 15,000 mPa·s or less and the viscosity at 70°C is 1,500 mPa·s or less in the temperature-viscosity curve. Examples of the polyester polyol (a-1) include bifunctional polyester polyols made from sebacic acid, bifunctional polyester polyols made from sebacic acid and 3-methyl-pentanediol, and bifunctional polyester polyols made from isophthalic acid and 3-methyl-pentanediol. These bifunctional polyester polyols are commercially available, for example, as "URIC SE 2013C" (sebacic acid-based polyester polyol manufactured by Ito Oil Mills, Ltd., Mn: 2,000), "Kuraray Polyol P-2050" (manufactured by Kuraray Co., Ltd., Mn: 2,000), and "Kuraray Polyol P-2030" (manufactured by Kuraray Co., Ltd., Mn: 2,000). As the polyester polyol (a-1), one type may be used, or two or more types may be used in combination. The blending amount of the polyester polyol (a-1) contained in the raw material composition of the urethane (meth)acrylate (component A) is preferably, for example, 35 to 75% by weight relative to the raw material composition of the urethane (meth)acrylate (component A).

[0024] (1-2) Isocyanate (a-2) The isocyanate (a-2) is a compound having an isocyanate group. Examples of isocyanate (a-2) that can be used include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 2,4-tolylene diisocyanate dimer, p-xylylene diisocyanate, m-xylylene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, hexamethylene diisocyanate, 4,4-trimethylhexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, bis(isocyanatomethyl)cyclohexane, norbornene diisocyanate, lysine diisocyanate, a reaction product of 1 mole of a diol with 2 moles of a diisocyanate, and an isocyanurate polyisocyanate, biuret polyisocyanate, or adduct polyisocyanate derived from a bifunctional isocyanate. However, the isocyanate is not limited to the above isocyanates.

[0025] It is preferable to use an alicyclic isocyanate as the isocyanate (a-2). Examples of alicyclic isocyanates include 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate (isophorone diisocyanate) (IPDI). The use of an alicyclic isocyanate suppresses yellowing of the artificial nail composition. It also suppresses excessively high viscosity of the urethane (meth)acrylate (component A). As a result, the artificial nail composition can be easily prepared. Only one type of isocyanate (a-2) may be used as the isocyanate (a-2). Alternatively, two or more types of isocyanates (a-2) may be used in combination. The isocyanate (a-2) may include isocyanates other than alicyclic isocyanates (e.g., aliphatic isocyanates). However, the main component of the isocyanate (a-2) contained in the raw material of the urethane (meth)acrylate (component A) is preferably an alicyclic isocyanate. The blending amount of the isocyanate (a-2) contained in the raw material composition of the urethane (meth)acrylate (component A) is, for example, preferably 14 to 35 wt %, more preferably 16 to 31 wt %, relative to the raw material composition of the urethane (meth)acrylate (component A).

[0026] (1-3) Hydroxy(meth)acrylate (a-3) The raw material composition of urethane (meth)acrylate (component A) contains a (meth)acrylate having a hydroxy group (OH group). Examples of the hydroxy(meth)acrylate (a-3) include hydroxypropyl methacrylate (HOP(N)), hydroxypropyl acrylate, hydroxyethyl (meth)acrylate, hydroxybutyl (meth)acrylate, hydroxyhexyl (meth)acrylate, hydroxyethyl acrylamide (HEAA), N-hydroxyethyl (meth)acrylamide, 3-butanediol (meth)acrylate, 1,4-butanediol (meth)acrylate, 1,6-hexanediol (meth)acrylate, 3-methylpentanediol (meth)acrylate, pentaerythritol tri(meth)acrylate, and dipentaerythritol penta(meth)acrylate. As the hydroxy(meth)acrylate (a-3), only one type of hydroxy(meth)acrylate (a-3) may be used. Alternatively, two or more types of hydroxy(meth)acrylate (a-3) may be used in combination. The amount of hydroxy(meth)acrylate (a-3) contained in the raw material composition of the urethane(meth)acrylate (component A) is, for example, preferably 5 to 16 wt %, and more preferably 9 to 12 wt %, relative to the raw material composition of the urethane(meth)acrylate (component A).

[0027] (1-4) Diol (a-4) Having Branches and Being Liquid at 20° C. The diol (a-4) is used as a chain extender. The diol (a-4) is preferably a bifunctional amorphous chain extender having a molecular weight of 50 or more and 300 or less, more preferably 100 or more and 200 or less. Examples of the branched diol (a-4) that is liquid at 20°C include 3-methyl-1,5-pentanediol (MPD), C8 branched diols (e.g., 2-ethyl-1,3-hexanediol (HD)), 2-methyl-1,3-propanediol, 2-methyl-2,4-pentanediol, 1,2-hexanediol, 1,2-propanediol, 1,2-butanediol, 1,2-pentanediol, 1,3-butanediol, 1,4-pentanediol, 2,4-pentanediol, 2,5-hexanediol, 2,3-butanediol, 2-methylene-1,3-propanediol, 2,4-dimethyl-2,4-pentanediol, neopentyl glycol, and 2-methyl-1,8-octanediol. Only one type of diol (a-4) may be used as the diol (a-4). Alternatively, two or more types of diol (a-4) may be used in combination. The blending amount of the branched diol (a-4) that is liquid at 20°C and contained in the raw material composition of the urethane (meth)acrylate (component A) is, for example, preferably 0.8 to 14 wt%, more preferably 1.0 to 12 wt%, and even more preferably 1.1 to 11 wt%, relative to the raw material composition of the urethane (meth)acrylate (component A).

[0028] The molar ratio of the branched diol (a-4) that is liquid at 20°C to the polyester polyol (a-1) is preferably in the range of 0.25 or more and 5 or less, more preferably in the range of more than 0.25 and 5 or less. Typically, when removing artificial gel nails from nails, the remover uses a solvent such as acetone to swell and dissolve the gel nail, then scrapes it off. However, the solvent used for removal not only dissolves the gel nail, but also strips the natural nail of its oils and moisture. Therefore, the use of such solvents can cause dryness of the nails and skin, as well as whitening, chipping, and cracking of the nails.

[0029] In contrast, there is a technique for replacing gel nails with artificial nails called "fill-in." In this technique, the original artificial nail is not completely removed. At least one layer of the original artificial nail is left on the nail. A new gel nail is then applied on top of the remaining layer. Fill-in does not require the use of a solvent to remove the artificial nail. This reduces the burden (damage) on the natural nail. Gel nails used for fill-in require higher adhesion to the natural nail after hardening than regular gel nails, and a hardness that allows for filing. However, generally, the harder the artificial nail, the lower the adhesion (the more likely it is to peel). Artificial nail compositions using a urethane (meth)acrylate (component A) with a molar ratio in the range of 0.25 to 5 have a hardness suitable for fill-in and also good adhesion. Therefore, both hardness and adhesion are possible.

[0030] In addition, conventional fill-in artificial nail compositions generally use urethane (meth)acrylates other than the urethane (meth)acrylate (component A) of the present invention. Examples of commonly used conventional urethane (meth)acrylates include di-HEMA trimethylhexyl dicarbamate. When conventional urethane (meth)acrylates are incorporated, the artificial nail becomes hard and easy to file. As a result, fill-in becomes easier. On the other hand, for example, di-HEMA trimethylhexyl dicarbamate has disadvantages such as reduced adhesion, high curing heat generation, and skin sensitization. In the present invention, the addition of a urethane (meth)acrylate (second urethane (meth)acrylate) other than component A, such as di-HEMA trimethylhexyl dicarbamate, is not inhibited. However, for the reasons mentioned above, it is important that the content of the urethane (meth)acrylate (component A) be 38% by weight or more and 75% by weight or less based on the total amount of components of the artificial nail composition.

[0031] The R value of the urethane (meth)acrylate (component A) is preferably in the range of 1.25 or more and 2.0 or less. The R value is the molar ratio of isocyanate groups to hydroxyl groups. The measured number average molecular weight of a urethane (meth)acrylate (component A) having an R value within this range is in the range of 10,000±5,000. An artificial nail composition having an R value within this range has good adhesion to natural nails, hardness that does not crack even when bent, and conformability.

[0032] (2) (Meth)acrylate Having a Hydroxyl Group (Component B) The (meth)acrylate having a hydroxyl group (Component B) is a reactive diluent. A monofunctional acrylic monomer having a hydroxyl group can be suitably used as the (meth)acrylate having a hydroxyl group (Component B). When a (meth)acrylate having a hydroxyl group (Component B) is used, the artificial nail composition is likely to swell in a solvent such as acetone. This improves the removal (removability) of the artificial nail composition. Furthermore, the use of a (meth)acrylate having a hydroxyl group (Component B) can increase the hydrophilicity of the artificial nail composition. This improves the affinity with nails and enhances the adhesion between the nail and the artificial nail composition. Examples of the (meth)acrylate having a hydroxyl group (component B) include 2-hydroxypropyl methacrylate (HOP(N)), 2-hydroxypropyl acrylate, 2-hydroxyethyl (meth)acrylate, hydroxybutyl (meth)acrylate, hydroxyhexyl (meth)acrylate, hydroxyethyl acrylamide (HEAA), N-hydroxyethyl (meth)acrylamide, 3-butanediol (meth)acrylate, 1,4-butanediol (meth)acrylate, 1,6-hexanediol (meth)acrylate, 3-methylpentanediol (meth)acrylate, pentaerythritol tri(meth)acrylate, and dipentaerythritol penta(meth)acrylate. As the (meth)acrylate having a hydroxyl group (component B), only one type of (meth)acrylate having a hydroxyl group (component B) may be used. Alternatively, two or more types of (meth)acrylates having a hydroxyl group (component B) may be used in combination. The content of the hydroxyl group-containing (meth)acrylate (component B) is preferably within a range of, for example, 20% by weight to 60% by weight, based on 100% by weight of the entire artificial nail composition. Furthermore, the content of the hydroxyl group-containing (meth)acrylate (component B) is preferably within a range of, for example, 150% by weight or less, based on 100% by weight of the urethane (meth)acrylate (component A).

[0033] The artificial nail composition may contain a (meth)acrylate having no hydroxyl group as a reactive diluent. A monofunctional (meth)acrylic monomer having no hydroxyl group can be suitably used as the reactive diluent. Examples of the monofunctional (meth)acrylate having one (meth)acryloyl group and no hydroxyl group include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, neopentyl (meth)acrylate, cyclohexyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, and the like. (meth)acrylate, isobornyl (meth)acrylate, phenyl (meth)acrylate, benzyl (meth)acrylate, esters of monohydric alcohols such as N-acryloyloxyethylhexahydrophthalimide with (meth)acrylic acid; acrylamide, dimethylacrylamide, diethylacrylamide, methacrylamide, N-methyl(meth)acrylamide, N-ethyl(meth)acrylamide, N-methylol(meth)acrylamide, N-methoxymethyl(meth)acrylamide, N-butoxymethyl(meth)acrylamide, N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N,N-dipropyl(meth)acrylamide, N,N-diisopropyl(meth)acrylamide, N,N-dibutyl(meth)acrylamide, N,N-diisobutyl(meth)acrylamide, N,N-di-tert-butyl(meth)acrylamide, N,N-diheptyl(meth)acrylamide, N,N-dioctyl(meth)acrylamide, N,N-di-tert- (meth)acryloyl group-containing amide compounds such as octyl(meth)acrylamide, N,N-didodecyl(meth)acrylamide, N,N-dioctadecyl(meth)acrylamide, N,N-dimethylaminopropyl(meth)acrylamide, and N,N-dimethylaminoethyl(meth)acrylamide; nitrogen-containing alkyl(meth)acrylates such as N,N-dimethylaminoethyl(meth)acrylate, N,N-diethylaminoethyl(meth)acrylate, and N-t-butylaminoethyl(meth)acrylate;Glycidyl (meth)acrylate; 4-(meth)acryloyloxymethyl-2-cyclohexyl-1,3-dioxolane, adamantyl (meth)acrylate, (2-methyl-2-ethyl-1,3-dioxolan-4yl)methyl (meth)acrylate, cyclic trimethylolpropane formal (meth)acrylate, (2-isobutyl-2-methyl-1,3-dioxolan-4yl)methyl (meth)acrylate, (2-ethyl-2-methyl-1,3-dioxolan-4yl)methyl (meth)acrylate, (1,4-dioxaspiro[4,5]decan-2yl)methyl (meth)acrylate, tetrafurfuryl alcohol oligo(meth)acrylate, alkoxylated tetrahydrofuran and one or more selected from the group consisting of heterocycle-containing (meth)acrylates such as tetrahydrofurfuryl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, (3-ethyloxetan-3-yl)methyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate glycidyl ether, (meth)acryloylmorpholine, N-(meth)acryloyloxyethylhexahydrophthalimide, pentamethylpiperidyl (meth)acrylate, isocyanuric acid di(meth)acrylate, isocyanuric acid tri(meth)acrylate, triazine tri(meth)acrylate, N-(meth)acryloxysuccinimide, and N-(meth)acryloxyphthalimide;

[0034] The (meth)acrylate without a hydroxyl group is preferably an acrylic monomer having an alicyclic skeleton, such as isobornyl (meth)acrylate. When an acrylic monomer having an alicyclic skeleton is used as the (meth)acrylate without a hydroxyl group, good dilution properties are obtained, and the generation of curing heat is suppressed. When both a (meth)acrylate with a hydroxyl group (component B) and a (meth)acrylate without a hydroxyl group are contained, the total content of these components is preferably within the range of, for example, 20% by weight to 60% by weight, with the entire artificial nail composition being 100% by weight. Of the total content, it is preferable that component B accounts for 50% by weight or more.

[0035] (3) Photopolymerization Initiator (Component C) The photopolymerization initiator (Component C) is preferably one that can be sufficiently cured with ultraviolet light from an LED light source or light with a wavelength of approximately 365 to 410 nm (a portion of visible light) and that can suppress the amount of heat generated during curing. Examples of such photopolymerization initiators that can be used include benzoyl ethers, benzil ketals, acid esters, α-aminoalkylphenones, acylphosphine oxides, benzophenones, thioxanthones, titanocenes, and oxime esters. These initiators are preferred because they do not inhibit the radical generation reaction even when light is absorbed by dyes, pigments, or photopolymerizable compounds, have high radical generation efficiency, and can enhance the curing properties of the nail enamel composition. For example, alkylphenone-based photopolymerization initiators, acylphosphine oxide-based photopolymerization initiators, titanocene-based photopolymerization initiators, and oxime ester photopolymerization initiators can be used. In particular, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide is preferably used as the photopolymerization initiator (component C).

[0036] Examples of alkylphenone photopolymerization initiators include benzyl dimethyl ketal (BDK) compounds, α-hydroxyalkylphenone compounds, and α-aminoalkylphenone compounds. Examples of benzyl dimethyl ketal (BDK) photopolymerization initiators include 2,2-dimethoxy-1,2-diphenylethan-1-one. Examples of α-hydroxyalkylphenone photopolymerization initiators include 1-hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methylpropionyl)benzyl]phenyl}-2-methylpropan-1-one, and phenylglyoxylic acid methyl ester. Examples of the α-aminoalkylphenone photopolymerization initiator include 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1, 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone.

[0037] Examples of the acylphosphine oxide photopolymerization initiator include monoacylphosphine oxide (MAPO) compounds and bisacylphosphine oxide (BAPO) compounds. An example of a monoacylphosphine oxide (MAPO) compound is 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide. An example of a bisacylphosphine oxide (BAPO) compound is bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide.

[0038] An example of a titanocene photopolymerization initiator is bis(η5-2,4-cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrol-1-yl)-phenyl)titanium. An example of an oxime ester photopolymerization initiator is 1,2-octanedione, 1-[4-(phenylthio)-, 2-(O-benzoyloxime)], ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, 1-(O-acetyloxime).

[0039] Only one type of photopolymerization initiator (component C) among these may be used. Alternatively, two or more types of photopolymerization initiators (component C) may be used in combination. The content of the photopolymerization initiator (component C) is preferably, for example, in the range of 2.4 wt % to 3.4 wt %, more preferably 2.6 wt % to 3.2 wt %, based on 100 wt % of the total artificial nail composition.

[0040] (4) Other Components The artificial nail composition may contain additives such as oils and fats, higher alcohols, higher fatty acids, silicone oils, other oily components, silica, silane coupling agents, surfactants, fragrances, solvents such as ethanol and ethyl acetate, polymerization inhibitors, antioxidants, UV absorbers, antibacterial agents, antifungal agents, and pigments, provided that the objectives of the present invention are not impaired. Purple pigments such as Purple No. 401 may also be added. Some artificial nail compositions may turn yellow due to the influence of photopolymerization initiators, etc. Adding a purple pigment, such as Purple No. 401, which is a complementary color to yellow, can prevent the composition from appearing yellow. The amount of purple pigment added is preferably within a range of, for example, 0.0002% by weight to 0.002% by weight, with the total artificial nail composition being 100% by weight.

[0041] Artificial nails are typically composed of three resin layers: a base layer, a color layer, and a top layer. The base layer constitutes the portion of the artificial nail that comes into contact with the natural nail. The color layer is decorated and determines the design of the artificial nail. The top layer is the outermost layer and functions to enhance the durability and gloss of the artificial nail. Note that the artificial nail may be configured without any of the base layer, color layer, and top layer. Furthermore, the artificial nail may have multiple layers selected from the base layer, color layer, and top layer. The artificial nail composition of the present invention has excellent adhesion to the natural nail without the use of an acid component. Therefore, it can be suitably used to form the base layer of an artificial nail. However, the use of the artificial nail composition of the present invention is not limited to the base layer. The color layer or top layer of an artificial nail may also be formed using the artificial nail composition of the present invention.

[0042] <Method for Producing Artificial Nail Composition> The artificial nail composition according to the embodiment of the present invention can be produced, for example, by the following method.

[0043] (1) Preparation of Urethane (Meth)acrylate (Component A) Polyurethane (terminal -NCO group) was obtained by reacting polyester polyol (a-1), branched diol (a-4) that is liquid at 20°C, and isocyanate (a-2) at 80°C to 130°C for 2 hours (urethane polymerization). Hydroxy(meth)acrylate (a-3) and a polymerization catalyst were added to the reaction mixture. Further reaction was continued at 80°C to 100°C for 2 hours, whereby the terminal -NCO group reacted with the OH group of the hydroxy(meth)acrylate, bonding the hydroxy(meth)acrylate (a-3) to the polyurethane terminal. As a result, urethane (meth)acrylate (Component A) with acrylated terminals was obtained. During the second-stage reaction, it is preferable to add a polymerization inhibitor, polymerization catalyst, antioxidant, etc. Methoquinone, for example, can be used as the polymerization inhibitor. The amount added is approximately 0.1 to 2 wt% of the nonvolatile content. The amount of polymerization catalyst added is approximately 0.01% by weight based on the nonvolatile content. The polymerization catalyst is preferably added by dissolving it in a solvent. The amount of solvent for the polymerization catalyst added is approximately 1% by weight based on the nonvolatile content. The amount of antioxidant added is approximately 0.1% by weight based on the nonvolatile content. (2) Preparation of Artificial Nail Composition: A visible light stability imparting agent, pigment, etc. are added to the obtained urethane (meth)acrylate (component A), hydroxyl group-containing (meth)acrylate (component B), and photopolymerization initiator (component C). The artificial nail composition is obtained by dissolving and mixing at room temperature to 80°C in the dark. The stability imparting agent is an optional component, and examples thereof include methylhydroquinone. The stability imparting agent is effective in preventing natural hardening of the artificial nail composition.

[0044] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to these.

[0045] Example 1 "URIC SE 2013C" (sebacic acid-based polyester polyol, Mn: 2,000, manufactured by Ito Oil Mills, Ltd.) was used as a polyester polyol (a-1) that was liquid at 20°C, isophorone diisocyanate (IPDI) was used as an isocyanate (a-2), hydroxypropyl methacrylate (HOP(N)) was used as a hydroxy(meth)acrylate (a-3), and 3-methyl-1,5-pentanediol (MPD) was used as a branched diol (a-4) that was liquid at 20°C.

[0046] 1. Preparation of Artificial Nail Composition (1) Preparation of Urethane (Meth)acrylate (Component A) 63.9 parts of URIC SE 2013C (a-1), 3.8 parts of MPD (a-4), and 18.9 parts of IPDI (a-2) were reacted for 2 hours (urethane polymerization) while adjusting the reaction temperature to fall within the range of 80°C to 130°C, to obtain a polyurethane (terminal -NCO group). The molar ratio of the diol (a-4) to the polyester polyol (a-1) was 1.0 ((a-1):(a-4) = 1:1). The R value of the resulting polyurethane (molar ratio of isocyanate groups to hydroxyl groups) was 1.33. Furthermore, 12.3 parts of HOP(N)(a-3), 0.1 parts of methoquinone, 0.01 parts of a polymerization catalyst (ADK STAB 465E), 1.0 parts of a solvent for the polymerization catalyst (MEK), and 0.1 parts of an antioxidant (JPP-100) were added, and the reaction was carried out for 2 hours while adjusting the temperature during the reaction to be within the range of 80°C to 100°C, thereby obtaining a urethane (meth)acrylate (component A) in which the terminal —NCO groups were acrylated.

[0047] (2) Preparation of Artificial Nail Composition The artificial nail composition of this example was obtained by dissolving and mixing 100 parts of urethane (meth)acrylate (component A), 40 parts of HOP(N) as a (meth)acrylate having a hydroxyl group (component B), 4.2 parts of triphenylphosphine oxide (TPO) as a photopolymerization initiator (component C), 0.14 parts of methylhydroquinone, and 0.00112 parts of pigment (Purple No. 401) at room temperature to 80°C under a light-shielded condition.

[0048] 2. Evaluation of Physical Properties of Artificial Nail Composition The obtained artificial nail composition was evaluated for the following physical properties. The results are shown in Table 1. The artificial nail composition of this example was rated "B" in the hardness evaluation, but was rated "A" in all other items. The overall rating was "G."

[0049] (1) Leveling Property Evaluation After applying the artificial nail composition with a brush, the state was observed and evaluated according to the following criteria: A: Brush marks disappeared in less than 10 seconds B: Brush marks disappeared in 10 to less than 60 seconds C: Brush marks did not disappear in 60 seconds or more

[0050] (2) Curing Heat Evaluation One gram of artificial nail composition was dropped onto a substrate (PET film) at once. Five seconds after dropping, an irradiation device was used to irradiate the dropped artificial nail composition with LED light for 30 seconds. The irradiation device was "NAILERS' Mix Light ULM-1" (manufactured by Beauty Nailer Co., Ltd., output 48 watts, wavelength 365 nm & 405 nm). This allowed the artificial nail composition to cure. The maximum surface temperature during the 30-second irradiation was measured and evaluated according to the following criteria: A: Less than 80°C B: 80°C or higher but less than 100°C C: 100°C or higher

[0051] (3) Durability Adhesion Evaluation The artificial nail composition was applied to the substrate described below using a brush. The artificial nail composition was cured using the irradiation device. A top gel (Nail Parfait high gloss top gel manufactured by Nonstress Co., Ltd.) was applied over the cured artificial nail composition. The top gel was then cured using the irradiation device. The entire laminate of the artificial nail composition and the top gel was immersed in water at 45°C. Then, visual evaluation was performed according to the following criteria. The substrate was a deer bone (manufactured by Petzroot Co., Ltd., product name "Hard Deer Bone") commercially available as a dog toy. The deer bone used had its surface smoothed by polishing with a nail file (sponge nail file 180G). A: No lifting occurs for 4 weeks or more. B: No lifting occurs for 2 weeks or more but less than 4 weeks. C: Lifting occurs in less than 2 weeks.

[0052] (4) Flexibility Evaluation The artificial nail composition was applied to a substrate (PET film), spread to a thickness of 1 mm, and then cured by irradiating with LEDs using the irradiation device to obtain a test piece for flexibility evaluation. The test piece was folded in half and evaluated according to the following criteria: A: No cracks; B: Cracks or whitening without cracks; C: Cracks.

[0053] (5) Hardness Evaluation 1.3 grams of the artificial nail composition was applied to a substrate (nail tip) and cured using the irradiation device to obtain a nail tip test piece. Next, the nail tip test piece was wiped with cotton soaked in ethanol to remove the uncured gel (artificial nail composition) from the nail tip test piece. Furthermore, the surface of the artificial nail composition was smoothed by polishing the nail tip test piece with a nail file (150G). Polishing consisted of rubbing the nail tip test piece with a load of 100 g and moving the nail file 5 cm at a time. After repeating the polishing 50 times, the weight difference before and after polishing was measured to calculate the weight of the artificial nail composition that had been removed. Evaluation was based on the following criteria: A: The weight was 5 mg or more (easy to remove); B: The weight was 2 mg or more but less than 5 mg (can be removed, but it takes time); C: The weight was less than 2 mg (difficult to remove).

[0054] (6) Solvent Removal Evaluation The obtained artificial nail composition (base gel) was applied to a nail and cured using the irradiation device to form an artificial nail. Then, cotton soaked in acetone was placed on the cured artificial nail. Furthermore, to prevent the acetone from volatilizing, the artificial nail was left for 5 minutes while wrapped in aluminum foil together with the cotton. This caused the artificial nail to swell and partially peel off from the nail. The peeled area was evaluated according to the following criteria: A: Peeled area is 70% or more B: Peeled area is 30% or more but less than 70% C: Peeled area is less than 30%

[0055] (7) Storage Stability Evaluation The obtained artificial nail composition (base gel) was stored in a light-shielding jar at 45°C for one month. The viscosity after storage was evaluated. A: Viscosity increase or decrease of 50% or less B: Viscosity increase of more than 50% but less than 100% C: Viscosity increase of 100% or more or gelation

[0056] (8) Overall rating: G: All items are A or B. NG: There is at least one C in one item.

[0057] The artificial nail compositions of Examples 2 to 15 and Comparative Examples 1 and 2 were obtained using the compositions shown in Table 1 or 2 in the same manner as in Example 1.

[0058] Example 2 This example is an artificial nail composition prepared in the same manner as in Example 1, using 100 parts of a urethane (meth)acrylate (Component A) obtained by varying the molar ratio of the diol (a-4) to the polyester polyol (a-1). Other ingredients included 30 parts of HOP(N) as the hydroxyl group-containing (meth)acrylate (Component B), 3.9 parts of triphenylphosphine oxide (TPO) as the photopolymerization initiator (Component C), 0.13 parts of methylhydroquinone, and 0.00104 parts of a pigment (Violet No. 401). The molar ratio of the diol (a-4) to the polyester polyol (a-1) was 0.5 ((a-1):(a-4) = 2:1). The R value was 1.33. The number average molecular weight Mn (main peak measured value by GPC) of the urethane (meth)acrylate (Component A) was 9,978. The artificial nail composition of this example was rated "B" in the hardness evaluation, but was rated "A" in all other items. The overall evaluation was "G."

[0059] Example 3 The artificial nail composition of this example was obtained in the same manner as in Example 2, using the composition shown in Table 1, in which the molar ratio of the diol (a-4) to the polyester polyol (a-1) was 1.0 ((a-1):(a-4) = 1:1). The R value of the resulting polyurethane was 1.50. The number average molecular weight Mn (main peak value measured by GPC) of the urethane (meth)acrylate (component A) was 7,197. The artificial nail composition of this example was rated "B" in the curing heat evaluation, durable adhesion evaluation, and hardness evaluation, but was rated "A" in all other categories. The overall rating was "G."

[0060] [Example 4] The artificial nail composition of this example was obtained in the same manner as in Example 2, using the composition shown in Table 1, in which the molar ratio of the diol (a-4) to the polyester polyol (a-1) was 3.0 ((a-1):(a-4)=1:3). The R value of the resulting polyurethane was 1.33. The artificial nail composition of this example was rated "A" in all categories. The overall rating was "G."

[0061] [Example 5] The artificial nail composition of this example was obtained in the same manner as in Example 2, using the composition shown in Table 1, in which the molar ratio of the diol (a-4) to the polyester polyol (a-1) was 5.0 ((a-1):(a-4) = 1:5). The R value of the resulting polyurethane was 1.33. The artificial nail composition of this example was rated "B" in the flexibility evaluation, but was rated "A" in all other items. The overall rating was "G."

[0062] Example 6 The artificial nail composition of this example was prepared using the same composition as in Example 1, except that a urethane (meth)acrylate (component A) obtained by changing the molar ratio of the diol (a-4) to the polyester polyol (a-1) to be 0.25 ((a-1):(a-4)=4:1) was used. The R value of the resulting polyurethane was 1.33. The artificial nail composition of this example was rated "B" in the hardness and solvent removability evaluations, but was rated "A" in all other categories. The overall rating was "G." However, if the amount of component (a-4) is low, the resulting artificial nail tends to be softer. The hardness rating was rated "B." Although it did not receive a rating of "C," the artificial nail was harder to file than the artificial nails obtained in the other examples.

[0063] Example 7 The artificial nail composition of this example was obtained using the same compounds as in Example 1 and the composition shown in Table 1, except that hydroxyethyl acrylamide (HEAA) was used as the hydroxy(meth)acrylate (a-3). The molar ratio of the diol (a-4) to the polyester polyol (a-1) was 1.0 ((a-1):(a-4)=1:1). The R value of the resulting polyurethane was 1.33. The artificial nail composition of this example was rated "B" in the curing heat evaluation, but was rated "A" in all other categories. The overall rating was "G."

[0064] Example 8 The artificial nail composition of this example was obtained using the same compounds as in Example 1 and the composition shown in Table 1, except that 2-ethyl-1,3-hexanediol (OD) was used as the branched diol (a-4) that is liquid at 20°C. The molar ratio of the diol (a-4) to the polyester polyol (a-1) was 1.0 ((a-1):(a-4)=1:1). The R value of the resulting polyurethane was 1.33. The artificial nail composition of this example received a "B" rating in the hardness evaluation, but received an "A" rating in all other categories. The overall rating was "G."

[0065] Example 9 The artificial nail composition of this example was obtained by adding di-HEMA trimethylhexyl dicarbamate to the urethane (meth)acrylate (component A), hydroxyl group-containing (meth)acrylate (component B), photopolymerization initiator (component C), methylhydroquinone, and pigment (Purple No. 401) obtained in Example 1. The di-HEMA trimethylhexyl dicarbamate was a second urethane (meth)acrylate (a urethane (meth)acrylate different from component A). The molar ratio of the diol (a-4) to the polyester polyol (a-1) was 1.0 ((a-1):(a-4) = 1:1). The R value of the resulting polyurethane was 1.33. In this example, the content of the urethane (meth)acrylate (component A) was 53.9 wt % based on the total amount of components constituting the artificial nail composition. The artificial nail composition of this example was rated "B" in the curing heat evaluation, durable adhesion evaluation, and solvent removability evaluation, but was rated "A" in all other items. The overall evaluation was "G."

[0066] Comparative Example 1 In this comparative example, the same compounds as in Example 9 were used, except that a urethane (meth)acrylate (component A) prepared according to the composition shown in Table 1 was used. The content of the urethane (meth)acrylate (component A) was 37.3% by weight based on the total amount of components constituting the artificial nail composition. The molar ratio of the diol (a-4) to the polyester polyol (a-1) was 1.0 ((a-1):(a-4)=1:1). The R value of the resulting polyurethane was 1.33. The artificial nail composition of this comparative example was rated "C" in the curing heat evaluation, durable adhesion evaluation, and solvent removability evaluation. The overall evaluation was "NG."

[0067] The results of Example 9 and Comparative Example 1 show that increasing the proportion of the second urethane (meth)acrylate component other than the urethane (meth)acrylate (component A) tends to decrease removability with a solvent. It can be seen that when the content of the urethane (meth)acrylate (component A) is within a specified range relative to the total amount of components constituting the artificial nail composition, an artificial nail composition with favorable removability with a solvent can be obtained.

[0068] Example 10 The artificial nail composition of this example was obtained using the same compounds as in Example 1 and the composition shown in Table 2, except that the amounts added were changed so that the R value was 1.25. The molar ratio of the diol (a-4) to the polyester polyol (a-1) was 1.0 ((a-1):(a-4)=1:1). The R value of the resulting polyurethane was 1.25. The artificial nail composition of this example received a "B" rating in the leveling ability evaluation and hardness evaluation, but received an "A" rating in all other categories. The overall rating was "G."

[0069] Example 11 The artificial nail composition of this example was obtained using the same compounds as in Example 1 and the formulation shown in Table 2, except that the amounts added were changed so that the R value was 2.0. The molar ratio of the diol (a-4) to the polyester polyol (a-1) was 1.0 ((a-1):(a-4)=1:1). The R value of the resulting polyurethane was 2.0. The number-average molecular weight Mn (main peak measured value by GPC) of the urethane (meth)acrylate (component A) was 6,629. The artificial nail composition of this example received a "B" rating in the curing heat evaluation and durable adhesion evaluation, but received an "A" rating in all other categories. The overall rating was "G."

[0070] Example 12 The artificial nail composition of this example was obtained using the same compounds as in Example 1 and the composition shown in Table 2, except that "P-2050" (sebacic acid-based polyester polyol, Mn: 2,000, manufactured by Kuraray Co., Ltd.) was used as the polyester polyol (a-1), which is liquid at 20°C. The molar ratio of the diol (a-4) to the polyester polyol (a-1) was 1.0 ((a-1):(a-4) = 1:1). The R value of the resulting polyurethane was 1.33. The artificial nail composition of this example was rated "B" in the curing heat evaluation, durable adhesion evaluation, and hardness evaluation, but was rated "A" in all other categories. The overall rating was "G."

[0071] Example 13 The artificial nail composition of this example was prepared using the same compounds as in Example 1 and the composition shown in Table 2, except that "P-2030" (an isophthalic acid-based polyester polyol manufactured by Kuraray Co., Ltd., Mn: 2,000) was used as the polyester polyol (a-1) that is liquid at 20°C, and 2-ethyl-1,3-hexanediol (OD) was used as the branched diol (a-4) that is liquid at 20°C. The molar ratio of the diol (a-4) to the polyester polyol (a-1) was 1.0 ((a-1):(a-4) = 1:1). The R value of the resulting polyurethane was 1.33. The artificial nail composition of this example was rated "B" in the leveling ability evaluation, but was rated "A" in all other categories. The overall rating was "G."

[0072] Example 14 This example is a low-viscosity artificial nail composition. The urethane (meth)acrylate (component A) obtained in Example 1 was used, and the content of the urethane (meth)acrylate (component A) was 44.1% by weight based on the total amount of components constituting the artificial nail composition. The molar ratio of the diol (a-4) to the polyester polyol (a-1) was 1.0 ((a-1):(a-4)=1:1). The R value of the resulting polyurethane was 1.33. The artificial nail composition of this example received a "B" rating in the curing heat evaluation, durable adhesion evaluation, and hardness evaluation, but received an "A" rating in all other categories. The overall rating was "G."

[0073] Example 15 This example is a low-viscosity artificial nail composition. The polyester polyol (a-1) is liquid at 20°C and contains "P-2030" (an isophthalic acid-based polyester polyol, Mn: 2,000, manufactured by Kuraray Co., Ltd.), and the branched diol (a-4) is liquid at 20°C. The urethane (meth)acrylate (component A) is made from 2-ethyl-1,3-hexanediol (OD). The content of the urethane (meth)acrylate (component A) is 38.8% by weight based on the total amount of components of the artificial nail composition. The molar ratio of the diol (a-4) to the polyester polyol (a-1) was 1.0 ((a-1):(a-4) = 1:1), and the R value of the resulting polyurethane was 1.33. The artificial nail composition of this example received a "B" rating in the durable adhesion evaluation and hardness evaluation, but received an "A" rating in all other evaluations. The overall rating was "G."

[0074] [Comparative Example 2] In this comparative example, the content of urethane (meth)acrylate (component A) in Example 14 was 35.9% by weight based on the total amount of components constituting the artificial nail composition. The molar ratio of the diol (a-4) to the polyester polyol (a-1) was 1.0 ((a-1):(a-4)=1:1), and the R value of the resulting polyurethane was 1.33. The artificial nail composition of this comparative example was rated "C" in the durable adhesion evaluation. The overall evaluation was "NG."

[0075]

[0076]

[0077] As described above, it can be seen that the present invention provides an artificial nail composition that has good durable adhesion to natural nails and is also easily removable with a solvent, without using acid components such as acrylic acid, methacrylic acid, and phosphoric acid that are used in conventional artificial nail compositions.

Claims

1. An artificial nail composition comprising a urethane (meth)acrylate (Component A), a (meth)acrylate having a hydroxyl group (Component B), and a photopolymerization initiator (Component C), wherein the urethane (meth)acrylate (Component A) contains a structure derived from a polyester polyol (a-1) that is liquid at 20°C, an isocyanate (a-2), a hydroxy (meth)acrylate (a-3), and a diol (a-4) having a branch and being liquid at 20°C, and the content of the urethane (meth)acrylate (Component A) is 38% by weight or more and 75% by weight or less based on the total amount of the components of the artificial nail composition.

2. The artificial nail composition according to claim 1, wherein the molar ratio of the diol (a-4) to the polyester polyol (a-1) is in the range of 0.25 or more and 5 or less.

3. The artificial nail composition according to claim 1, wherein the polyester polyol (a-1) is a polyester polyol having a number average molecular weight in the range of 1,000 or more and 3,000 or less.

4. The artificial nail composition according to claim 1, wherein the R value of the urethane (meth)acrylate (Component A) is in the range of 1.25 or more and 2.0 or less.

5. The artificial nail composition according to claim 1, wherein the molecular weight of the diol (a-4) is 300 or less.

6. The artificial nail composition according to claim 1, wherein when the urethane (meth)acrylate (Component A) is 100 parts, the (meth)acrylate having a hydroxyl group (Component B) is in the range of 30 parts or more and 150 parts or less.

Images