Primer coat resin composition for nails

Abstract

The purpose of the present invention is to provide a means for imparting adhesiveness to nails without sanding.　The present invention is a primer coat resin composition for nails, the composition containing components (A) and (B) but being free of a photo-radical initiator.　Component (A) is at least one selected from the group consisting of secondary alcohols having a molecular weight of at least 145 and a (meth)acryloyl group and tertiary alcohols having a molecular weight of at least 145 and having a (meth)acryloyl group (excluding component (B)). Component (B) is a phosphoric acid ester compound having a (meth)acryloyl group.

Description

Nail primer coating resin composition

[0001] The present invention relates to a primer coating resin composition for nails.

[0002] Conventionally, photocurable resin compositions (UV gel nails) containing photopolymerizable monomers and / or photopolymerizable oligomers have been used in the nail industry. These UV gel nails are used to decorate and make up nails by applying the resin to the nail using a brush or the like and then curing it by irradiating it with light. UV gel nails require adhesive properties, and various studies have been conducted on them. For example, Japanese Patent Laid-Open Publication No. 2010-53097 (equivalent to U.S. Patent Application Publication No. 2010 / 055057) discloses an artificial nail composition with improved adhesive properties, which contains a compound having a radically polymerizable unsaturated double bond, an acidic phosphorus compound, and a radical polymerization initiator.

[0003] Conventionally, when applying UV gel nails, the nail surface is sanded with a file or the like to create fine irregularities on the nail surface, and then the UV gel nail is applied over that to provide adhesion. However, creating irregularities on the nail surface can damage the nail, resulting in the problem that the patient's nails become thin and brittle after the cured UV gel nail is removed. Despite these problems, sufficient adhesion cannot be achieved without sanding, and a means of achieving sufficient adhesion without sanding has been sought.

[0004] Therefore, an object of the present invention is to provide a means for imparting adhesion to nails without sanding.

[0005] As a result of intensive research to achieve the above object, the inventors have discovered a nail primer coating resin composition that can impart adhesion to nails without sanding, and have completed the present invention.

[0006] The gist of the present invention will now be described.

[0007] [1] A nail primer coating resin composition comprising the following components (A) and (B), and containing no photoradical initiator: Component (A): at least one selected from the group consisting of a secondary alcohol having a molecular weight of 145 or more and having a (meth)acryloyl group, and a tertiary alcohol having a molecular weight of 145 or more and having a (meth)acryloyl group (excluding component (B)); Component (B): a phosphate ester compound having a (meth)acryloyl group. [2] The nail primer coating resin composition according to [1], further comprising an organic solvent as component (C). [3] The nail primer coating resin composition according to [1] or [2], wherein component (B) contains at least one of 2-(meth)acryloyloxyethyl acid phosphate and di(2-(meth)acryloyloxyethyl) acid phosphate. [4] The nail primer coating resin composition according to any one of [1] to [3], wherein the (B) component contains di(2-(meth)acryloyloxyethyl) acid phosphate. [5] The nail primer coating resin composition according to any one of [1] to [4], wherein the content of the (B) component is 0.01 to 10 parts by mass per part by mass of the (A) component. [6] The nail primer coating resin composition according to any one of [2] to [5], wherein the total content of the (A) component and the (B) component is 1.5 to 4.5 parts by mass per 25 parts by mass of the (C) component. [7] The nail primer coating resin composition according to any one of [2] to [6], wherein the (C) component contains an organic solvent having a boiling point of less than 80°C in an amount of 60% by mass or more relative to the total mass of the (C) component. [8] The nail primer coating resin composition according to any one of [1] to [7], which does not contain any of a primary alcohol having a (meth)acryloyl group, a secondary alcohol having a molecular weight of less than 145 and having a (meth)acryloyl group, and a tertiary alcohol having a molecular weight of less than 145 and having a (meth)acryloyl group. [9] The nail primer coating resin composition according to any one of [2] to [8], which consists only of the component (A), the component (B), and the component (C).

[10] A cured product obtained by curing a laminate having a primer coating layer formed from the nail primer coating resin composition according to any one of [1] to [9] and a layer formed from a photocurable resin composition for nail or artificial nail.

[11] A coating method comprising: applying the nail primer coating resin composition according to any one of [1] to [9] to a nail to form a primer coating layer; applying a photocurable resin composition for nail or artificial nail on top of the primer coating layer to form a layer of the photocurable resin composition for nail or artificial nail; and irradiating the layer of the photocurable resin composition for nail or artificial nail with active energy rays.

[0008] The nail primer coating resin composition according to the present invention will be described in detail below. In this specification, "X to Y" is used to mean that the numerical values ​​(X and Y) before and after it are included as the lower and upper limits, respectively, and means "X or more and Y or less." Unless otherwise specified, operations and measurements of physical properties are carried out under conditions of room temperature (20 to 25°C) and relative humidity of 40 to 50% RH. In this specification, the term "(meth)acryloyl" also includes the form (meth)acryloyloxy, and encompasses both acryloyl and methacryloyl. Therefore, for example, the term "(meth)acryloyl group" refers to an acryloyl group (H ２ C=CH-C(=O)-) and methacryloyl groups (H ２ C=C(CH ３ )—C(═O)—). Similarly, the term “(meth)acrylic” includes both acrylic and methacrylic. Thus, for example, the term “(meth)acrylic acid” includes both acrylic acid and methacrylic acid.

[0009] <Component (A)> The component (A) of the present invention is at least one selected from the group consisting of secondary alcohols having a molecular weight of 145 or more and a (meth)acryloyl group, and tertiary alcohols having a molecular weight of 145 or more and a (meth)acryloyl group. However, this does not include the component (B) described below. A secondary alcohol refers to a compound in which the carbon to which a hydroxy group is bonded is also bonded to two carbon atoms, and a tertiary alcohol refers to a compound in which the carbon to which a hydroxy group is bonded is also bonded to three carbon atoms. From the viewpoint of further improving adhesion, secondary alcohols are preferred. The component (A) is not particularly limited as long as it contains one or more hydroxy groups and one or more (meth)acryloyl groups. Furthermore, when the component (A) contains two or more hydroxy groups, it is preferable that the component (A) does not have a hydroxy group bonded to a primary carbon from the viewpoint of adhesion. That is, a —CH ２ It is preferable that the component (A) does not have an OH structure. The lower limit of the molecular weight of the component (A) is not particularly limited as long as it is 145 or more, but from the viewpoint of adhesion, the molecular weight of the component (A) is preferably 160 or more, more preferably 180 or more, and most preferably 200 or more. The upper limit of the molecular weight of the component (A) is not particularly limited, but from the viewpoint of improving adhesion, it is preferably 1000 or less, more preferably 800 or less, and most preferably 700 or less. This molecular weight can be calculated from the sum of the atomic weights of the atoms constituting the compound of the component (A).

[0010] Specific examples of secondary alcohols having a molecular weight of 145 or more and containing a (meth)acryloyl group include 3-hydroxybutyl methacrylate, 2-hydroxybutyl methacrylate, 3-hydroxypentyl (meth)acrylate, 2-hydroxypentyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl acrylate, bisphenol A diglycidyl ether (meth)acrylic acid adduct, tripropylene glycol diglycidyl ether (meth)acrylic acid adduct, glycerin diglycidyl ether acrylic acid adduct, 2-hydroxy-3-acrylpropyl methacrylate, etc. Specific examples of tertiary alcohols having a molecular weight of 145 or more and containing a (meth)acryloyl group include 3-methyl-3-hydroxybutyl (meth)acrylate, 4-methyl-4-hydroxypentyl (meth)acrylate, etc.

[0011] The component (A) may be used alone or in combination of two or more.

[0012] <Component (B)> The component (B) of the present invention is a phosphate ester compound having a (meth)acryloyl group. ３(wherein each R is independently a hydrogen atom or an organic group, and at least one R is an organic group). Specific examples include a phosphoric acid monoester compound, a phosphoric acid diester compound, and a phosphoric acid triester compound. From the viewpoint of further improving adhesion, a phosphoric acid monoester compound and a phosphoric acid diester compound are preferred, and a phosphoric acid diester compound is more preferred. The number of (meth)acryloyl groups is not particularly limited as long as there is one or more, but from the viewpoint of further improving adhesion, it is preferable that there are one to two (meth)acryloyl groups, and most preferably two. Specific examples of component (B) include 2-(meth)acryloyloxyethyl acid phosphate, which is a phosphoric acid monoester compound; di(2-(meth)acryloyloxyethyl) acid phosphate, which is a phosphoric acid diester compound; and triacryloyl phosphate and trimethacryloyl phosphate, which are phosphoric acid triester compounds.

[0013] From the viewpoint of adhesion, the component (B) preferably contains at least one of 2-(meth)acryloyloxyethyl acid phosphate and di(2-(meth)acryloyloxyethyl) acid phosphate, and more preferably contains at least one of 2-methacryloyloxyethyl acid phosphate and di(2-methacryloyloxyethyl) acid phosphate. Furthermore, according to another embodiment, from the viewpoint of adhesion, the component (B) particularly preferably contains di(2-(meth)acryloyloxyethyl) acid phosphate, and most preferably contains di(2-methacryloyloxyethyl) acid phosphate. The component (B) may be used singly or in combination of two or more.

[0014] The content of component (B) in the composition is preferably 0.01 to 10 parts by mass, more preferably 0.05 to 8 parts by mass, even more preferably 0.3 to 6 parts by mass, and most preferably 0.7 to 4 parts by mass, per part by mass of component (A). Having the content of component (B) within this range can impart high adhesion. Note that when two or more types of component (B) are used, the above content refers to the total amount.

[0015] <Component (C)> The composition of the present invention preferably contains an organic solvent as component (C). The inclusion of an organic solvent improves the wettability of the nail and the nail primer coating resin composition of the present invention, further improving adhesion and allowing the nail primer coating resin composition to be applied substantially uniformly to the nail surface. From the perspective of workability, component (C) preferably contains an organic solvent having a boiling point of less than 80°C. Here, the boiling point of the organic solvent refers to the boiling point at 1 atmosphere. Examples of organic solvents include acetone (boiling point 50°C), ethyl acetate (boiling point 77°C), ethanol (boiling point 78°C), and isopropanol (boiling point 82°C). Considering the effects on the human body and workability (volatility), ethanol is particularly preferred. Component (C) may be used alone or in combination of two or more. Component (C) may also contain an organic solvent with a boiling point of 80°C or higher. However, when an organic solvent with a boiling point of 80°C or higher is contained, from the viewpoint of workability, the content of the organic solvent with a boiling point of less than 80°C is preferably 60% by mass or more, and more preferably 70% by mass or more, of the total mass of component (C).

[0016] The total content of the (A) component and the (B) component is preferably 0.1 to 25 parts by mass, more preferably 0.25 to 10 parts by mass, even more preferably 0.5 to 8 parts by mass, particularly preferably 1 to 4.5 parts by mass, and most preferably 1.5 to 4.5 parts by mass, relative to 25 parts by mass of the (C) component. Having the total content of the (A) component and the (B) component within this range can impart good adhesion.

[0017] The nail primer coat resin composition of the present invention is used to improve adhesion between a photocurable resin composition and an adherend, and is particularly suitable for improving adhesion between a photocurable resin composition for nails or artificial nails and nails. The nail primer coat resin composition of the present invention does not contain a component that crosslinks and hardens when exposed to light such as ultraviolet light. The nail primer coat resin composition of the present invention is a composition that does not undergo a crosslinking reaction when simply applied to a nail. Another embodiment of the present invention includes an application method that includes applying the nail primer coat resin composition of the present invention to a nail to form a primer coat layer, applying a photocurable resin composition for nails or artificial nails on the primer coat layer to form a layer of the photocurable resin composition for nails or artificial nails, and irradiating the layer of the photocurable resin composition for nails or artificial nails with active energy rays. Yet another embodiment of the present invention includes a cured product obtained by curing a laminate having a primer coat layer formed from the nail primer coat resin composition and a layer formed from the photocurable resin composition for nails or artificial nails.

[0018] In the present invention, the term "artificial nail" refers to a layer formed on a human or animal nail for decorative and / or protective purposes. Other examples of artificial nails include resin substrates (false nails) of any shape intended for decorative and / or protective purposes. The shape of the artificial nail is not particularly limited, and it may be formed to cover the nail, or may be formed to be larger than the nail in order to lengthen the nail. It may also be formed for the purpose of adhering items such as stones to the nail to enhance its aesthetic appearance.

[0019] The photocurable resin composition for nails or artificial nails is a photocurable resin composition (UV gel nail) that can be used on nails or artificial nails, and is a photocurable resin composition that can form a cured layer on the nail or artificial nail by irradiating it with active energy rays such as ultraviolet light or visible light. Examples of photocurable resin compositions for nails or artificial nails include, but are not limited to, compositions containing a radical polymerizable compound and a photoradical initiator. Photocurable resin compositions for nails or artificial nails are classified into photocurable resin compositions for base coats, photocurable resin compositions for coloring, photocurable resin compositions for top coats, etc.

[0020] Artificial nails are generally composed of a base coat layer (a layer intended to provide adhesion to the nail, prevent color transfer, etc.) formed by applying a base coat photocurable resin composition to the surface of the nail and curing it, a color layer (a layer containing coloring materials and intended for decoration) formed by applying a color photocurable resin composition to the base coat layer and curing it, and a top coat layer (a layer intended for coating, providing gloss, improving aesthetics, etc.) formed by applying a top coat photocurable resin composition to the color layer and curing it. The nail primer coat resin composition of the present invention is preferably applied to the nail or artificial nail and used for the purpose of forming an artificial nail layer thereon, and from the viewpoint of excellent adhesion, it is particularly suitable for use in bonding the nail to the base coat layer.

[0021] When applying the nail primer coating resin composition of the present invention to nails, there is no need to sand the nail surface with a file or other tool to improve adhesion, as has been done in the past. A primer coating layer can be formed by directly applying the composition to the nail and, if component (C) is included, by drying component (C). It is preferable to apply the composition after removing dust, oil, moisture, etc. from the nail surface with a nail-specific solvent primarily containing ethanol. When applying the nail primer coating resin composition of the present invention, it is preferable to form a coating film using a brush or paintbrush. A photocurable resin composition for nails or artificial nails is applied onto the primer coating layer thus formed to form a layer of the photocurable resin composition for nails or artificial nails. The layer of the photocurable resin composition for nails or artificial nails is then cured by irradiating it with active energy rays such as ultraviolet light or visible light. Commercially available nail UV lamps or nail LED lamps can be used as curing irradiators. The irradiation time is preferably 15 to 120 seconds, and, considering the effects on the fingers, more preferably 20 to 70 seconds. The integrated light amount is preferably 300 to 1500 mJ / cm ２ and more preferably 500 to 1000 mJ / cm ２ is.

[0022] The nail primer coating resin composition of the present invention does not contain a photoradical initiator. A photoradical initiator is a compound that decomposes to generate radical species upon irradiation with active energy rays such as ultraviolet light or visible light. If the primer coating layer contains a photoradical initiator, adhesion will not be improved even if each artificial nail layer is formed and then cured separately. Conversely, if the nail primer coating resin composition of the present invention does not contain a photoradical initiator, the primer coating layer remains on the nail surface and is partially compatible with the nail or the photocurable resin composition for artificial nails, improving adhesion between the nail and the artificial nail layer. Furthermore, since a photoradical initiator may cause yellowing and deteriorate the appearance, it is not preferable to include it in the nail primer coating resin composition of the present invention. Examples of photoradical initiators include acetophenone-based photoinitiators, benzoin-based photoinitiators, benzophenone-based photoinitiators, thioxanthone-based photoinitiators, and acylphosphine oxide-based photoinitiators. Examples of acetophenone-based photoinitiators include diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzyl dimethyl ketal, 4-(2-hydroxyethoxy)phenyl-(2-hydroxy-2-propyl)ketone, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-2-morpholino(4-thiomethylphenyl)propan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone, 2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanone oligomer, etc. Examples of benzoin-based photoinitiators include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, etc.Examples of the benzophenone-based photoinitiator include benzophenone, methyl o-benzoylbenzoate, 4-phenylbenzophenone, 4-benzoyl-4'-methyl-diphenyl sulfide, 3,3',4,4'-tetra(t-butylperoxycarbonyl)benzophenone, 2,4,6-trimethylbenzophenone, 4-benzoyl-N,N-dimethyl-N-[2-(1-oxo-2-propenyloxy)ethyl]benzenemethanaminium bromide, and (4-benzoylbenzyl)trimethylammonium chloride. Examples of thioxanthone-based photoinitiators include 2-isopropylthioxanthone, 4-isopropylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone, 1-chloro-4-propoxythioxanthone, 2-(3-dimethylamino-2-hydroxy)-3,4-dimethyl-9H-thioxanthone-9-one mesochloride, etc. Examples of acylphosphine oxide-based photoinitiators include, but are not limited to, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 2,4,6-trimethylbenzoylphenylethoxyphosphine oxide, etc.

[0023] <Optional Components> The nail primer coating resin composition of the present invention may further contain a radically polymerizable compound and various additives to the extent that they do not adversely affect the viscosity, transparency, adhesion, etc. Examples of such additives include a filler, a conductive filler, a silane coupling agent, a plasticizer, an adhesive, an antifoaming agent, a pigment, a rust inhibitor, a leveling agent, a dispersant, a rheology modifier, and a flame retardant.

[0024] Examples of the radical polymerizable compound include urethane (meth)acrylate oligomers, monofunctional, difunctional, or trifunctional (meth)acrylate monomers (i.e., (meth)acrylate monomers having 1 to 3 (meth)acryloyl groups), and (meth)acrylamide monomers (excluding the above-mentioned components (A) and (B)).

[0025] In addition, the optional radical polymerizable compound may include at least one compound selected from the group consisting of a primary alcohol having a (meth)acryloyl group, a secondary alcohol having a molecular weight of less than 145 and a (meth)acryloyl group, and a tertiary alcohol having a molecular weight of less than 145 and a (meth)acryloyl group. However, when these compounds are contained, the content is preferably 0.5 parts by mass or less, and more preferably 0.15 parts by mass or less, per part by mass of component (A) in order to avoid reducing adhesion. In one embodiment of the present invention, it is particularly preferable that the nail primer coating resin composition is substantially free of at least one compound selected from the group consisting of a primary alcohol having a (meth)acryloyl group, a secondary alcohol having a molecular weight of less than 145 and a (meth)acryloyl group, and a tertiary alcohol having a molecular weight of less than 145 and a (meth)acryloyl group. Here, "substantially free" includes both a form in which none of the compounds is contained (the content is 0 parts by mass) and a form in which the content of these compounds is more than 0 parts by mass and 0.001 parts by mass or less per part by mass of component (A).

[0026] In one embodiment of the present invention, it is most preferable that the nail primer coating resin composition does not contain any of the following: a primary alcohol having a (meth)acryloyl group; a secondary alcohol having a molecular weight of less than 145 and a (meth)acryloyl group; and a tertiary alcohol having a molecular weight of less than 145 and a (meth)acryloyl group.

[0027] The radical polymerizable compound may be a commercially available product or a synthetic product. These radical polymerizable compounds may be used alone or in combination of two or more.

[0028] The urethane (meth)acrylate oligomer is not particularly limited as long as it has a urethane bond and one or more (meth)acryloyl groups. The urethane (meth)acrylate oligomer may be a commercially available product or a synthetic product. Examples of methods for synthesizing the urethane (meth)acrylate oligomer include a method in which a urethane bond is formed by reacting a polyol with a polyisocyanate, and then adding a compound having a hydroxy group and a (meth)acryloyl group in the molecule or (meth)acrylic acid to the unreacted isocyanate group, and a method in which a compound having a hydroxy group and a (meth)acryloyl group in the molecule or (meth)acrylic acid is added to a polyisocyanate to form a urethane bond. However, the synthesis method is not limited to these methods. Here, an oligomer refers to a polymer in which two to several dozen monomer units are repeated. The monomer units may include monomer units other than (meth)acrylate monomers. The weight-average molecular weight of the urethane (meth)acrylate oligomer is preferably 1,000 to 100,000, more preferably 2,500 to 90,000, and particularly preferably 3,000 to 80,000. Having the weight-average molecular weight of the urethane (meth)acrylate oligomer within this range improves workability and adhesion. Here, the weight-average molecular weight is a value measured by gel permeation chromatography (GPC) using polystyrene as a standard substance. From the standpoint of workability, the urethane (meth)acrylate oligomer is preferably liquid (liquid-like) at 25°C (i.e., has fluidity). The urethane (meth)acrylate oligomer may be used alone or in combination of two or more. Examples of the polyol include polyether polyol, polyester polyol, caprolactone diol, bisphenol polyol, polyisoprene polyol, hydrogenated polyisoprene polyol, polybutadiene polyol, hydrogenated polybutadiene polyol, castor oil polyol, and polycarbonate diol.Examples of the polyisocyanate include aromatic polyisocyanates, alicyclic polyisocyanates, aliphatic polyisocyanates, etc. Examples of the aromatic polyisocyanate include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, tetramethylxylylene diisocyanate, diphenylmethane diisocyanate, naphthalene-1,5-disocyanate, and triphenylmethane triisocyanate. Examples of alicyclic polyisocyanates include isophorone diisocyanate, bis(4-isocyanatocyclohexyl)methane, 1,3-bis(isocyanatomethyl)cyclohexane, 1,4-bis(isocyanatomethyl)cyclohexane, norbornane diisocyanate, and bicycloheptane triisocyanate. Examples of aliphatic polyisocyanates include hexamethylene diisocyanate, 1,3,6-hexamethylene triisocyanate, and 1,6,11-undeca triisocyanate. Examples of the compound having a hydroxy group and a (meth)acryloyl group include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, mono(meth)acrylates of dihydric alcohols such as ethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, and polyethylene glycol, and mono(meth)acrylates or di(meth)acrylates of trihydric alcohols such as trimethylolethane, trimethylolpropane, and glycerin. Examples of catalysts used in the synthesis of urethane (meth)acrylate oligomers include lead oleate, tetrabutyltin, antimony trichloride, triphenylaluminum, trioctylaluminum, dibutyltin dilaurate, copper naphthenate, zinc naphthenate, zinc octylate, zinc octenoate, zirconium naphthenate, cobalt naphthenate, tetra-n-butyl-1,3-diacetyloxydistannoxane, triethylamine, 1,4-diazabicyclo[2.2.2]octane, and N-ethylmorpholine.The amount of these catalysts used is preferably 0.0001 to 10 parts by mass per 100 parts by mass of the total amount of reaction raw materials. The reaction temperature is usually 10 to 100°C, and preferably 30 to 90°C. The urethane (meth)acrylate oligomer may be diluted with a solvent or other monomers at the raw material stage. These urethane (meth)acrylate oligomers may be used alone or in combination of two or more.

[0029] The monofunctional (meth)acrylate monomer is not particularly limited, and examples thereof include ethyl (meth)acrylate, n-butyl (meth)acrylate, tert-butyl (meth)acrylate, isobutyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isodecyl (meth)acrylate, butoxydiethylene glycol (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, glycidyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, caprolactone-modified tetrahydrofurfuryl (meth)acrylate, cyclohexyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxy (meth)acrylate, isobornyl (meth)acrylate, adamantyl (meth)acrylate, benzene Examples of the acrylates include methyl (meth)acrylate, phenyl (meth)acrylate, phenoxyethyl (meth)acrylate, phenoxydiethylene glycol (meth)acrylate, phenoxytetraethylene glycol (meth)acrylate, nonylphenoxyethyl (meth)acrylate, butoxyethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, glycerol (meth)acrylate, trifluoroethyl (meth)acrylate, γ-(meth)acryloxypropyltrimethoxysilane, γ-acryloxypropyltrimethoxysilane, morpholinoethyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, and N,N-dimethylaminopropyl (meth)acrylate. These monofunctional (meth)acrylate monomers may be used alone or in combination of two or more.

[0030] The bifunctional (meth)acrylate monomer is not particularly limited, but examples thereof include 1,3-butylene glycol di(meth)acrylate, 1,4-butylene glycol di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,6-hexane glycol di(meth)acrylate, ethylene glycol di(meth)arylate, tetraethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, propylene ...ethylene glycol di(meth)acrylate, ethylene glycol di(meth)acrylate, ethylene glycol di(meth)acrylate, ethylene glycol di(meth)acrylate, ethylene glycol di(meth)acrylate, ethylene glycol di(meth)acrylate, ethylene glycol di(meth)acrylate, ethylene glycol di(meth)acrylate, ethylene glycol di(meth)acrylate, ethylene glycol di(meth)acrylate, ethylene glycol di(meth)acrylate, ethylene glycol di(meth)acrylate, ethylene glycol di(meth Examples of the difunctional (meth)acrylate include tripropylene glycol di(meth)acrylate, ethylene oxide-modified neopentyl glycol di(meth)acrylate, propylene oxide-modified neopentyl glycol di(meth)acrylate, bisphenol A di(meth)acrylate, neopentyl glycol-modified trimethylolpropane di(meth)acrylate, dicyclopentenyl di(meth)acrylate, ethylene oxide-modified dicyclopentenyl di(meth)acrylate, and di(meth)acryloyl isocyanurate. These difunctional (meth)acrylate monomers may be used alone or in combination of two or more. The trifunctional (meth)acrylate monomer is not particularly limited, and examples thereof include, but are not limited to, trimethylolpropane tri(meth)acrylate, ethylene oxide (EO)-modified trimethylolpropane tri(meth)acrylate, propylene oxide (PO)-modified trimethylolpropane tri(meth)acrylate, epichlorohydrin (ECH)-modified trimethylolpropane tri(meth)acrylate, ECH-modified glycerol tri(meth)acrylate, tris((meth)acryloyloxyethyl)isocyanurate, etc. These trifunctional (meth)acrylate monomers may be used alone or in combination of two or more.

[0031] Examples of the (meth)acrylamide monomer are not particularly limited, but include (meth)acryloylmorpholine, dimethyl(meth)acrylamide, diethyl(meth)acrylamide, isopropyl(meth)acrylamide, hydroxyethyl(meth)acrylamide, etc. These (meth)acrylamide monomers may be used alone or in combination of two or more.

[0032] The nail primer coating resin composition of the present invention may further contain a filler to the extent that the object of the present invention is not impaired, for the purpose of improving the elastic modulus, flowability, etc. of the cured product. Specific examples of the filler include inorganic powders, organic powders, etc.

[0033] Examples of inorganic powder fillers include, but are not limited to, glass, fumed silica, alumina, mica, ceramics, silicone rubber powder, calcium carbonate, aluminum nitride, carbon powder, kaolin clay, dried clay minerals, dried diatomaceous earth, kaolin, etc. These inorganic powders may be used alone or in combination of two or more.

[0034] The fumed silica is blended for the purpose of adjusting the viscosity of the nail primer coating resin composition, and is preferably fumed silica that has been surface-treated with dimethylsilane, trimethylsilane, alkylsilane, methacryloxysilane, organochlorosilane, polydimethylsiloxane, hexamethyldisilazane, or the like. Examples of commercially available fumed silica include, but are not limited to, Aerosil (registered trademark) R972, R972V, R972CF, R974, R976, R976S, R9200, RX50, NAX50, NX90, RX200, RX300, R812, R812S, R8200, RY50, NY50, RY200S, RY200, RY300, R104, R106, R202, R805, R816, T805, R711, and R7200 (all manufactured by Nippon Aerosil Co., Ltd.). These fumed silicas may be used alone or in combination of two or more.

[0035] Examples of organic powder fillers include, but are not limited to, powders containing resins such as polyethylene, polypropylene, polystyrene, nylon, polyester, polyvinyl alcohol, polyvinyl butyral, polycarbonate, polymethyl (meth)acrylate, etc. These organic powders may be used alone or in combination of two or more.

[0036] The nail primer coating resin composition of the present invention may further contain a conductive filler. Examples of conductive fillers include, but are not limited to, fillers containing metals such as gold, silver, platinum, nickel, and palladium, and plated particles in which organic polymer particles are coated with a thin metal film. These conductive fillers may be used alone or in combination of two or more.

[0037] The nail primer coating resin composition of the present invention may further contain a silane coupling agent. Examples of silane coupling agents include γ-chloropropyltrimethoxysilane, octenyltrimethoxysilane, glycidoxyoctyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane, γ-ureidopropyltriethoxysilane, and p-styryltrimethoxysilane, but are not limited to these. These silane coupling agents may be used alone or in combination of two or more.

[0038] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. In the following, the nail primer coating resin composition will also be simply referred to as a resin.

[0039] <Preparation of nail primer coating resin composition> Each component was mixed in the parts by mass shown in Table 1 below using a planetary mixer in an environment of 25°C for 60 minutes to prepare a nail primer coating resin composition. Details of each component are as follows. Also, blank spaces in Table 1 below indicate that the component was not used.

[0040] <Component (A) and Comparative Components> A-1: ​​Bisphenol A diglycidyl ether methacrylic acid adduct (secondary alcohol having a molecular weight of 512 and two methacryloyl groups: Epoxy Ester 3000MK, manufactured by Kyoeisha Chemical Co., Ltd.) A-2: 2-hydroxy-3-methacryloylpropyl acrylate (secondary alcohol having a molecular weight of 214 and one methacryloyl group and one acryloyl group: NK Ester 701A, manufactured by Shin-Nakamura Chemical Co., Ltd.) A-3: 2-hydroxy-3-phenoxypropyl acrylate (secondary alcohol having a molecular weight of 222 and one acryloyl group: NK Ester 702A, manufactured by Shin-Nakamura Chemical Co., Ltd.) A'-1: hydroxypropyl methacrylate (secondary alcohol having a molecular weight of 144 and one methacryloyl group: HPMA, manufactured by Nippon Shokubai Co., Ltd.) A'-2: Ethoxylated bisphenol A dimethacrylate (a compound having a molecular weight of 466, two methacryloyl groups, and no hydroxyl group: BPE-80N, manufactured by Shin-Nakamura Chemical Co., Ltd.) A'-3: Hydroxyethyl methacrylate (a primary alcohol having a molecular weight of 130 and one methacryloyl group: HEMA, manufactured by Nippon Shokubai Co., Ltd.).

[0041] <Component (B) and Comparative Components> B-1: di(2-methacryloyloxyethyl) acid phosphate (Light Ester P-2M, manufactured by Kyoeisha Chemical Co., Ltd.) B-2: 2-methacryloyloxyethyl acid phosphate (JPA-514, manufactured by Johoku Chemical Industry Co., Ltd.) B-3: 2-methacryloyloxyethyl acid phosphate (Light Ester P-1M, manufactured by Kyoeisha Chemical Co., Ltd.) B'-1: 2-methacryloyloxyethyl succinic acid (Light Ester HO-MS(N), manufactured by Kyoeisha Chemical Co., Ltd.) B'-2: 2-acrylamido-2-methylpropanesulfonic acid (reagent).

[0042] <Component (C)> C-1: Ethanol (boiling point 78°C: reagent) C-2: Isopropanol (boiling point 82°C: reagent).

[0043] The test methods used in the examples and comparative examples in Table 1 are as follows.

[0044] [Appearance Check] After preparing the composition as described above, the composition was placed in a glass bottle. After one hour had passed, the state of the composition was visually checked and the appearance was evaluated according to the following evaluation criteria. In order not to impair the aesthetic appearance of the artificial nail layer, it is preferable that the appearance be rated "A".

[0045] Evaluation criteria: A: transparent B: cloudy or separated.

[0046] [Confirmation of Adhesion] The treatment was performed on the fingernails (10 in total) of one person. First, dust and oil were removed using a nail-specific solvent (mainly ethanol). Next, the nail primer coating resin composition described in the Examples and Comparative Examples was applied with a brush and left to dry for 60 seconds. Next, Excellent Base (components: acrylate oligomer, acrylate monomer, photopolymerization initiator, silica) manufactured by Prianfa Co., Ltd. was applied as a base coat to a wet thickness of approximately 100 μm. The application was performed with a brush. The base coat was then cured by irradiating it with ultraviolet light for 30 seconds using a nail LED lamp (rated voltage: 100-110 V, 50-60 Hz, power consumption: 36 W, wavelength: 350-400 nm). Using the same method as for curing the base coat, the color coat and top coat were applied to the surface of the base coat and cured in order. The color coat used was Color EX (color: pale peach) manufactured by Prianfa Co., Ltd., and the top coat used was Cangel EX manufactured by Prianfa Co., Ltd. The day of treatment was counted as day 1, and the number of days until the first peeling occurred between one nail and the hardened layer was recorded as "adhesion" (days). Adhesion is preferably 15 days or more, and more preferably 25 days or more.

[0047] [Confirmation of Drying Time] The treatment was performed on the fingernails (10 in total) of one person. First, dust and oil were removed using a nail-specific solvent (mainly ethanol). Next, the nail primer coating resin composition described in the Examples and Comparative Examples was applied using a brush. When the coating film was touched with a toothpick, whether or not the toothpick became wet was visually confirmed according to the following evaluation criteria, and the average time for 10 toothpicks was recorded as "drying time." Considering workability, a rating of "A," "B," or "C" was preferable, with "A" or "B" being more preferable, and "A" being even more preferable.

[0048] Evaluation criteria: "A" The toothpick becomes wet within 15 seconds. "B" The toothpick becomes wet within 16 to 30 seconds. "C" The toothpick becomes wet within 31 to 45 seconds. "D" The toothpick remains wet even after 46 seconds.

[0049] The constitutions of the nail primer coating resin compositions of the Examples and Comparative Examples and the evaluation results are shown in Table 1 below.

[0050]

[0051]

[0052] Table 1 shows that the compositions of Examples 1 to 12 were nail primer coating resin compositions with excellent appearance, adhesion, and drying properties. Adhesion was particularly good when B-1, which has a phosphate group on the side chain, was used as component (B). On the other hand, the composition of Comparative Example 1 used a secondary alcohol with a molecular weight of less than 145 instead of component (A), resulting in poor adhesion. Furthermore, in Comparative Example 2, a compound having no hydroxy group but a (meth)acryloyl group was used instead of component (A), resulting in poor adhesion. In Comparative Example 3, a primary alcohol was used instead of component (A), resulting in poor adhesion. In Comparative Example 4, the absence of component (A) resulted in poor adhesion. In Comparative Example 5, 2-methacryloyloxyethyl succinic acid was used instead of component (B), resulting in poor adhesion. In Comparative Example 6, 2-acrylamido-2-methylpropanesulfonic acid was used instead of component (B), resulting in insoluble residue and poor appearance and adhesion. In Comparative Example 7, the component (B) was not contained, and therefore the adhesion was poor.

[0053] Furthermore, the following test was carried out as a reference example: 0.5 parts by mass of the above-mentioned A-1 component and 0.5 parts by mass of the above-mentioned B-1 component were added to 100 parts by mass of Excellent Base (components: acrylate oligomer, acrylate monomer, photopolymerization initiator, silica) manufactured by Priampha Corporation, and mixed for 60 minutes in a light-shielded environment at 25°C using a planetary mixer to prepare a photocurable resin composition.

[0054] Next, the resulting photocurable resin composition was applied to the fingernails (10 in total) of one person. First, dust and oil were removed using a nail-specific solvent (mainly ethanol). Next, the photocurable resin composition was applied wet to a thickness of approximately 100 μm. Application was performed using a brush. The photocurable resin composition was then cured by irradiating it with ultraviolet light for 30 seconds using a nail LED lamp (rated voltage: 100-110 V 50-60 Hz, power consumption: 36 W, wavelength: 350-400 nm). The color coat and top coat were then cured on the surface of the cured product of the photocurable resin composition using the same method as in the adhesion test above, and adhesion was confirmed using the same criteria as in the adhesion test above. As a result, peeling occurred between the nail and the cured layer after 12 days.

[0055] As can be seen from the above-mentioned Reference Examples, the nail primer coating resin composition of the present invention can improve adhesion by applying it to nails before applying a photocurable resin composition.

[0056] The nail primer coating resin composition of the present invention can improve the adhesion of photocurable resin compositions and can therefore be widely used in the nail field.

[0057] This application is based on Japanese Patent Application No. 2023-217675, filed on December 25, 2023, the disclosure of which is incorporated herein by reference in its entirety.

Claims

1. A primer coat resin composition for nails, which contains the following component (A) and component (B) and does not contain a photoinitiator: Component (A): At least one selected from the group consisting of a secondary alcohol having a molecular weight of 145 or more and having a (meth)acryloyl group, and a tertiary alcohol having a molecular weight of 145 or more and having a (meth)acryloyl group (however, excluding component (B)) Component (B): A phosphate ester compound having a (meth)acryloyl group.

2. The primer coat resin composition for nails according to claim 1, further containing an organic solvent as component (C).

3. The primer coat resin composition for nails according to claim 1, wherein the component (B) contains at least one of 2-(meth)acryloyloxyethyl acid phosphate and di(2-(meth)acryloyloxyethyl) acid phosphate.

4. The primer coat resin composition for nails according to claim 1, wherein the component (B) contains di(2-(meth)acryloyloxyethyl) acid phosphate.

5. The primer coat resin composition for nails according to claim 1, wherein the content of the component (B) is 0.01 to 10 parts by mass with respect to 1 part by mass of the component (A).

6. The primer coat resin composition for nails according to claim 2, wherein the total content of the component (A) and the component (B) is 1.5 to 4.5 parts by mass with respect to 25 parts by mass of the component (C).

7. The primer coat resin composition for nails according to claim 2, wherein the component (C) contains an organic solvent having a boiling point of less than 80°C in an amount of 60% by mass or more based on the total mass of the component (C).

8. The primer coat resin composition for nails according to claim 1, which does not contain any of a primary alcohol having a (meth)acryloyl group, a secondary alcohol having a molecular weight of less than 145 and having a (meth)acryloyl group, and a tertiary alcohol having a molecular weight of less than 145 and having a (meth)acryloyl group.

9. The primer coat resin composition for nails according to claim 2, which consists only of the component (A), the component (B), and the component (C).

10. A cured product obtained by curing a laminate having a primer coat layer formed from the primer coat resin composition for nails according to any one of claims 1 to 9 and a layer formed from a photocurable resin composition for nails or artificial nails.

11. A coating method comprising: applying the primer coat resin composition for nails according to any one of claims 1 to 9 to the nails to form a primer coat layer; applying a photocurable resin composition for nails or artificial nails on the layer of the primer coat to form a layer of the photocurable resin composition for nails or artificial nails; and irradiating active energy rays from above the layer of the photocurable resin composition for nails or artificial nails.

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