Photocurable resin composition for nails or artificial nails, cured product, and method for coating nails or artificial nails

Abstract

Provided is a photocurable resin composition for nails or artificial nails, the composition having low curing heat.　The present invention provides a photocurable resin composition for nails or artificial nails, the composition containing components (A) to (D), indicated below, wherein the molecular weight of the component (C) is equal to or greater than 200: the component (A) is a urethane (meth)acrylate oligomer; the component (B) is a monomer selected from the group consisting of a (meth)acrylate monomer, a (meth)acrylamide monomer, and a (meth)acrylic acid (excluding the component (A)); the component (C) is a compound having a polyglycerin that does not have a (meth)acryloyl group and / or a polyglyceryl ether skeleton that does not have a (meth)acryloyl group; and the component (D) is a photoinitiator.

Description

[Technical Field]

[0001] The present invention relates to a photocurable resin composition, a cured product, and a method for coating nails or artificial nails, all suitable for coating nails or artificial nails. [Background technology]

[0002] Conventionally, in the nail field, photocurable resin compositions (UV nail gels) containing photopolymerizable monomers and / or oligomers are known. These UV nail gels are applied to the nails using a brush or the like, and then cured by exposure to light to decorate and beautify the nails, resulting in a nail cosmetic film with a beautiful shine and high adhesion to the nail. Because this process involves curing the resin directly on the nail, the heat generated during curing is directly transferred to the nail, which can cause pain. Therefore, there has been a demand for resins that generate less heat during curing.

[0003] Japanese Patent Publication No. 2020-12015 discloses a photocurable resin composition having a polytetramethylene glycol skeleton and 2 to 5 functional groups in a urethane (meth)acrylate resin, a (meth)acrylate monomer, a polyether-modified polysiloxane copolymer, and a photopolymerization initiator, wherein the exothermic temperature during curing is less than 55°C. [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] The inventors are diligently studying photocurable resin compositions for nails or artificial nails that have low curing heat, such as those described in Japanese Patent Publication No. 2020-12015.

[0005] Therefore, the present invention aims to provide a photocurable resin composition for nails or artificial nails that generates low curing heat.

[0006] Another object of the present invention is to provide a photocurable resin composition that can produce a cured product having sufficient hardness. [Means for solving the problem]

[0007] The gist of this invention is described below; [1] A photocurable resin composition for nails or artificial nails comprising the following components (A) to (D), wherein the molecular weight of component (C) is 200 or more; (A) Ingredients: Urethane (meth)acrylate oligomer (B) Component: A monomer selected from the group consisting of (meth)acrylate monomer, (meth)acrylamide monomer, and (meth)acrylic acid (excluding component (A)). (C) Components: Polyglycerin without (meth)acryloyl groups and / or compounds having a polyglyceryl ether skeleton without (meth)acryloyl groups. (D) Component: Photoinitiator.

[0008] [2] The photocurable resin composition for nails or artificial nails according to [1], wherein the molecular weight of component (C) is 200 or more and 5,000 or less.

[0009] [3] The photocurable resin composition for nails or artificial nails according to [1] or [2], wherein component (C) is polyglycerin and / or polyoxyalkylene polyglyceryl ether that does not have a (meth)acryloyl group.

[0010] [4] A photocurable resin composition for nails or artificial nails according to any of [1] to [3], further comprising (E) water.

[0011] [5] A photocurable resin composition for nails or artificial nails according to any one of [1] to [4], wherein component (D) is an acylphosphine oxide-based photoinitiator and / or an alkylphenone-based photoinitiator.

[0012] [6] A photocurable resin composition for nails or artificial nails according to any one of [1] to [5], comprising 10 to 200 parts by mass of component (B) per 100 parts by mass of component (A), and comprising 0.1 to 50 parts by mass of component (C) and 0.1 to 15 parts by mass of component (D) per 100 parts by mass of component (A) and component (B).

[0013] [7] A photocurable resin composition for nails or artificial nails according to any one of [1] to [6], further comprising a polyfunctional thiol compound.

[0014] [8] A photocurable resin composition for nails or artificial nails described in any of [1] to [7] that satisfies the following conditions; A photocurable resin composition X for nails or artificial nails and a resin composition Y that does not contain component (C) in resin composition X are prepared, and the maximum DSC peak value of resin composition X: α (mW) and the maximum DSC peak value of resin composition Y: β (mW) are both 100 - (α / β × 100) > 5%.

[0015] A cured product obtained by curing a photocurable resin composition for nails or artificial nails described in any of [9][1] to [8].

[0016] A method for coating a nail or artificial nail, comprising applying a photocurable resin composition for nails or artificial nails described in any of

[10] [1] to [8] to the nail or artificial nail to form a coating film, and then curing the coating film by irradiating it with active energy rays. [Modes for carrying out the invention]

[0017] Embodiments of the invention are described below. However, this disclosure is not limited to the embodiments described below. In this specification, "X~Y" means a range that includes the numerical values ​​(X and Y) described before and after it as the lower and upper limits. Furthermore, unless otherwise specified, "%" of concentration represents mass concentration "mass%", and ratios represent mass ratios unless otherwise specified. Furthermore, unless otherwise specified, operations and measurements of physical properties, etc., are performed under conditions of room temperature (20~25℃) / relative humidity 40~50%RH. Furthermore, "A and / or B" specifically means at least one of A and B, and means A, B, and combinations of A and B.

[0018] <Photocurable resin composition for nails or artificial nails> One form of the present invention relates to a photocurable resin composition for artificial nails (hereinafter, also referred to as "photocurable resin composition" or simply "composition"), which contains the following components (A) to (D), and the molecular weight of component (C) is 200 or more; Component (A): Urethane (meth)acrylate oligomer Component (B): A monomer selected from the group consisting of (meth)acrylate monomer, (meth)acrylamide monomer, and (meth)acrylic acid (excluding component (A)) Component (C): Polyglycerin having no (meth)acryloyl group and / or a compound having a polyglyceryl ether skeleton having no (meth)acryloyl group Component (D): Photoinitiator

[0019] According to one form of the present invention, it is possible to provide a photocurable resin composition for nails or artificial nails with low curing heat. Further, the photocurable resin composition of one form of the present invention has a viscosity suitable for the operation of applying to nails and artificial nails. Furthermore, according to the photocurable resin composition which is one form of the present invention, a cured product having sufficient hardness (rigidity) as a coating for nails and artificial nails can be obtained.

[0020] <(A) component> Component (A) contained in the photocurable resin composition according to the present invention is a urethane (meth)acrylate oligomer. A urethane (meth)acrylate oligomer is an oligomer having one or more urethane bonds and one or more (meth)acryloyl groups. Adding a urethane (meth)acrylate oligomer improves adhesion to nails or artificial nails, and improves the curability and strength of the photocurable resin composition (coating film). In this specification, the urethane (meth)acrylate oligomer may have the (meth)acryloyl group in the form of a (meth)acryloyloxy group. Also, the term "(meth)acryloyl" includes both acryloyl and methacryloyl. Therefore, for example, the term "(meth)acryloyl group" includes both acryloyl group (H2C=CH-C(=O)-) and methacryloyl group (H2C=C(CH3)-C(=O)-). Similarly, the term "(meth)acrylate" encompasses both acrylate and methacrylate, and the term "(meth)acrylic" encompasses both acrylic and methacrylic. Furthermore, "oligomer" refers to a polymer in which monomer units are repeated two to several dozen times.

[0021] Component (A) is not particularly limited as long as it is an oligomer having one or more urethane bonds and one or more (meth)acryloyl groups, but it is preferable to have 2 to 6 (meth)acryloyl groups, more preferably 2 to 3, and even more preferably 3. Having 2 to 6 (meth)acryloyl groups can contribute to reducing the curing heat of this photocurable resin composition. Furthermore, it is preferable that the (meth)acryloyl groups of component (A) are acryloyl groups. In addition to urethane bonds and (meth)acryloyl groups, it may also have other functional groups such as carboxyl groups, phosphate groups, epoxy groups, hydroxyl groups, etc.

[0022] The weight-average molecular weight of the oligomer of component (A) is preferably 1,000 to 100,000, and more preferably 2,000 to 70,000. Within this range, good curability of the cured product can be achieved while maintaining a viscosity that allows for good workability. In this specification, the weight-average molecular weight is the value measured by gel permeation chromatography (GPC) using polystyrene as a standard substance.

[0023] Urethane (meth)acrylate oligomers having urethane bonds can be synthesized by forming urethane bonds through the reaction of a polyol and a polyisocyanate, and then adding a compound having a hydroxyl group and a (meth)acryloyl group in the molecule, or (meth)acrylic acid, to the unreacted isocyanate group. However, the method of synthesizing the (meth)acrylate oligomer is not limited to this method. Urethane (meth)acrylate oligomers preferably have a polyalkylene glycol skeleton, and more preferably have a polypropylene glycol skeleton. Having a polyalkylene glycol skeleton improves adhesion to nails or artificial nails. Furthermore, urethane (meth)acrylate oligomers preferably have a cyclic structure, and more preferably have an alicyclic structure. Furthermore, it is preferable to have two or more cyclic structures, and more preferably two. Having a cyclic structure in the urethane (meth)acrylate oligomer improves the curability of the photocurable resin composition of the present invention and the strength of the cured product.

[0024] Specific examples of commercially available products of component (A) include AH-600 (phenylglycidyl ether acrylate hexamethylene diisocyanate urethane prepolymer, having two (meth)acryloyl groups), AT-600 (phenylglycidyl ether acrylate toluene diisocyanate urethane prepolymer, having two (meth)acryloyl groups), and UA-306H (pentaerythritol triacrylate hexamethylene diisocyanate Urethane prepolymer (having 2 (meth)acryloyl groups), UF-8001G (non-yellowing type oligourethane acrylate, having 2 (meth)acryloyl groups) (manufactured by Kyoeisha Chemical Co., Ltd.), RUA-071 (hexafunctional urethane acrylate, having 6 (meth)acryloyl groups), RUA-003VE (15-functional urethane acrylate, having 15 (meth)acryloyl groups), RUA-075 (pentafunctional urethane acrylate, having 5 (meth)acryloyl groups), RUA-048 (trifunctional urethane acrylate, having 3 (meth)acryloyl groups) Examples include, but are not limited to, UN-9200A (polycarbonate-based bifunctional urethane acrylate with two (meth)acryloyl groups), UN-9000PEP (polycarbonate-based bifunctional urethane acrylate with two (meth)acryloyl groups), UN-7700 (polyester-based bifunctional urethane acrylate with two (meth)acryloyl groups), and KY-11 (polyether-based trifunctional urethane acrylate with three (meth)acryloyl groups) (manufactured by Negami Kogyo Co., Ltd.).

[0025] <(B) component> Component (B) of the photocurable resin composition according to the present invention is a monomer selected from the group consisting of (meth)acrylate monomer, (meth)acrylamide monomer, and (meth)acrylic acid (excluding component (A)). The (meth)acrylate monomer and (meth)acrylamide monomer are not particularly limited, and known ones can be used. Among these, the monomer of component (B) is preferably a monofunctional, difunctional, or trifunctional monomer. Furthermore, component (B) preferably contains a combination of multiple monomers with different numbers of functional groups, and more preferably contains monofunctional and difunctional monomers. By containing multiple monomers with different numbers of functional groups in component (B), it is possible to improve adhesion to nails or artificial nails.

[0026] In a photocurable resin composition according to one embodiment of the present invention, the content of component (B) (or the total amount thereof if two or more monomers are used in combination as component (B)) is preferably in the range of 10 to 200 parts by mass, and more preferably 15 to 150 parts by mass, per 100 parts by mass of component (A). By being within the above range, the photocurable resin composition of the present invention can produce a cured product that is tough and has excellent adhesion.

[0027] Specific examples of monofunctional (meth)acrylate monomers include lauryl (meth)acrylate, stearyl (meth)acrylate, ethyl carbitol (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, caprolactone-modified tetrahydrofurfuryl (meth)acrylate, cyclohexyl (meth)acrylate, dicyclopentanyl (meth)acrylate, isobornyl (meth)acrylate, benzyl (meth)acrylate, phenyl (meth)acrylate, phenoxyethyl (meth)acrylate, phenoxydiethylene glycol (meth)acrylate, phenoxytetraethylene glycol (meth)acrylate, nonylphenoxyethyl (meth)acrylate, nonylphenoxytetraethylene glycol (meth)acrylate, and methoxydiethylene glycol. (meth)acrylate, ethoxydiethylene glycol (meth)acrylate, butoxyethyl (meth)acrylate, butoxytriethylene glycol (meth)acrylate, 2-ethylhexyl polyethylene glycol (meth)acrylate, 4-hydroxybutyl (meth)acrylate, nonylphenyl polypropylene glycol (meth)acrylate, methoxydipropylene glycol (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, polyethylene glycol (meth)acrylate, polypropylene glycol (meth)acrylate, epichlorohydrin-modified butyl (meth)acrylate, epichlorohydrin-modified phenoxy (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, N,Examples include, but are not limited to, N-diethylaminoethyl (meth)acrylate, 3-(meth)acryloyloxypropyl succinic acid, 4-(meth)acryloyloxybutyl succinic acid, 2-(meth)acryloyloxyethyl maleic acid, 3-(meth)acryloyloxypropyl maleic acid, 4-(meth)acryloyloxybutyl maleic acid, 2-(meth)acryloyloxyethyl hexahydrophthalic acid, 3-(meth)acryloyloxypropyl hexahydrophthalic acid, 4-(meth)acryloyloxybutyl hexahydrophthalic acid, 2-(meth)acryloyloxyethyl phthalic acid, 3-(meth)acryloyloxypropyl phthalic acid, 4-(meth)acryloyloxybutyl phthalic acid, and 2-hydroxyethyl methacrylate acid phosphate.

[0028] Among these, it is preferable that the monofunctional (meth)acrylate monomer includes a monofunctional (meth)acrylate monomer having a hydroxyl group. Specific examples of monofunctional (meth)acrylate monomers having a hydroxyl group include, but are not limited to, 2-hydroxyethyl (meth)acrylate and 2-hydroxypropyl (meth)acrylate. Among these, the monofunctional (meth)acrylate monomer having a hydroxyl group is preferably 2-hydroxypropyl (meth)acrylate, and more preferably 2-hydroxypropyl methacrylate. The monofunctional monomer having a hydroxyl group may be a commercially available product, and specific examples of commercially available products include, but are not limited to, Acryester® HP manufactured by Mitsubishi Rayon Co., Ltd.

[0029] Specific examples of difunctional (meth)acrylate monomers 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)acrylate, tetraethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, ethylene oxide modified neopentyl glycol di(meth)acrylate, pro Examples include, but are not limited to, pyrene oxide-modified neopentyl glycol di(meth)acrylate, bisphenol A di(meth)acrylate, ethylene oxide-modified bisphenol A di(meth)acrylate, epichlorohydrin-modified bisphenol A di(meth)acrylate, ethylene oxide-modified bisphenol S di(meth)acrylate, neopentyl glycol-modified trimethylolpropane di(meth)acrylate, dicyclopentenyl di(meth)acrylate, ethylene oxide-modified dicyclopentenyl di(meth)acrylate, diacryloyl isocyanurate, and dimethylol tricyclodecane di(meth)acrylate.

[0030] Specific examples of trifunctional (meth)acrylate monomers include, but are not limited to, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, EO-modified trimethylolpropane tri(meth)acrylate, PO-modified trimethylolpropane tri(meth)acrylate, ECH-modified trimethylolpropane tri(meth)acrylate, ECH-modified glycerol tri(meth)acrylate, and tris(acryloyloxyethyl) isocyanurate.

[0031] Specific examples of (meth)acrylamide monomers include, but are not limited to, (meth)acrylamide, N-methyl(meth)acrylamide, N-ethyl(meth)acrylamide, N-propyl(meth)acrylamide, Nn-butyl(meth)acrylamide, N-tert-butyl(meth)acrylamide, N-butoxymethyl(meth)acrylamide, N-isopropyl(meth)acrylamide, N-methylol(meth)acrylamide, N,N-dimethyl(meth)acrylamide, (meth)acryloylmorpholine, N,N-diethyl(meth)acrylamide, N-methyl-N-ethyl(meth)acrylamide, and N-hydroxyethyl(meth)acrylamide.

[0032] <(C) component> The (C) component contained in the photocurable resin composition according to the present invention is a compound having a polyglycerin and / or polyglyceryl ether skeleton without a (meth)acryloyl group, and has a molecular weight of 200 or more. The (C) component may be a compound represented by formula (1) and / or formula (2). By using the (C) component, the curing heat of the photocurable resin composition can be reduced. One or more types of the (C) component may be used.

[0033] Polyglycerin without a (meth)acryloyl group can be represented as shown in formula (1). Here, n in formula (1) is preferably an integer of 3 or more, and more preferably an integer between 3 and 45 from the viewpoint of reducing the curing heat of the photocurable resin composition.

[0034] [ka]

[0035] Polyglycerin without a (meth)acryloyl group may be a commercially available product. Specific examples of commercially available products include polyglycerin #310, #500, #750 (manufactured by Sakamoto Pharmaceutical Co., Ltd.), polyglycerin 20PW, and polyglycerin XPW (manufactured by Daicel Corporation).

[0036] Compounds having a polyglyceryl ether skeleton without a (meth)acryloyl group can be represented as shown in formula (2). Here, m is an integer of 1 or more, and R 1 These are each a basis that can be independently represented by equation (3). In equation (3), p refers to an integer of 0 or greater than or equal to 1, and R 3 R is hydrogen or alkyl group, 2 refers to an alkylene group. However, in formula (2), p is 1 or greater and / or p is 0 and R 3 R is an alkyl group 1 It contains at least one of the following: That is, R in equation (2) 1 At least one of the groups represented by is such that in formula (3), p is 1 or greater and / or p is 0 and R 3 This is the group that becomes an alkyl group.

[0037] [ka]

[0038] [ka]

[0039] If the molecular weight of the compound having a polyglyceryl ether skeleton without a (meth)acryloyl group is 200 or more, then m in formula (2) is not particularly limited as long as it is an integer of 1 or more. From the viewpoint of contributing to the reduction of curing heat, it is preferable that m in formula (2) is an integer of 2 or more, and more preferable that m is 2.

[0040] The total number of p in formula (3) contained in one molecule of a compound having a polyglyceryl ether skeleton without a (meth)acryloyl group is preferably 2 to 45, more preferably 3 to 35, even more preferably 4 to 25, and particularly preferably 5 to 15. Having a total number of p in the range of 2 to 45 can contribute to reducing the heat of curing.

[0041] The compound having a polyglyceryl ether skeleton without a (meth)acryloyl group may be a polyoxyalkylene polyglyceryl ether without a (meth)acryloyl group. The polyoxyalkylene polyglyceryl ether preferably contains at least one alkylene oxide (where p is an integer of 1 or more and R 3 is hydrogen). The polyoxyalkylene polyglyceryl ether is more preferably a polyoxyethylene polyglyceryl ether containing at least one ethylene oxide (where p is an integer of 1 or more, R 2 is an ethylene group and R 3 is hydrogen), or a polyoxypropylene polyglyceryl ether containing at least one propylene oxide (where p is an integer of 1 or more, R 2 is a propylene group and R 3 is hydrogen).

[0042] The compound having a polyglyceryl ether skeleton without a (meth)acryloyl group may be a commercially available product. Specific examples of commercially available products include SC-P750, SC-P1000, SC-P1600, SC-E750, SC-E1000, SC-E1500, SC-E2000 (manufactured by Sakamoto Yakuhin Kogyo Co., Ltd.), etc.

[0043] Some commercially available products that can be used as the above component (C) contain 0 to 15% water and / or 0 to 20% glycerin as impurities. However, the content of component (C) described below does not include the content of water and glycerin that may be contained as impurities. Also, the water contained as an impurity in the commercially available product that can be used as component (C) is included in component (E).

[0044] The molecular weight of component (C) is 200 or more, preferably 250 or more, more preferably 290 or more. Also, there is no particular upper limit to the molecular weight of component (C), but it is preferably 5,000 or less, more preferably 3,500 or less. The molecular weight of component (C) is a value calculated based on the theoretical calculation value, but when it cannot be derived from the calculated value, the value of the weight average molecular weight may also be used.

[0045] The content of component (C) in the photocurable resin composition according to the present invention (total amount if two or more are included) is preferably 0.1 to 50 parts by mass, more preferably 1 to 35 parts by mass, even more preferably 3 to 25 parts by mass, and particularly preferably 7 to 20 parts by mass, based on 100 parts by mass of the total content of components (A) and (B). By having the content of component (C) within the above range relative to the total content of components (A) and (B), a photocurable resin composition with low curing heat and excellent curability can be obtained.

[0046] <(D) component> Component (D) contained in a photocurable resin composition according to one embodiment of the present invention is a photoinitiator (photopolymerization initiator). Examples of photoinitiators that are component (D) include radical-type photoinitiators that generate radical species upon irradiation with active energy rays such as visible light, ultraviolet light, X-rays, and electron beams, cationic-type photoinitiators that generate cationic species, and anionic-type photogenerators that generate anionic species, but radical-type photoinitiators are preferred among these.

[0047] Examples of radical photoinitiators include alkylphenone compounds, acylphosphine oxide compounds, titanocene compounds, oxime ester compounds, benzoin compounds, acetophenone compounds, benzophenone compounds, thioxanthone compounds, α-acyloxime ester compounds, phenylglyoxylate compounds, benzyl compounds, azo compounds, diphenyl sulfide compounds, organic dye compounds, iron-phthalocyanine compounds, benzoin ether compounds, and anthraquinone compounds. Of these, from the viewpoint of reactivity, alkylphenone compounds or acylphosphine oxide compounds are preferred as radical photoinitiators. That is, component (D) is preferably an acylphosphine oxide photoinitiator and / or an alkylphenone photoinitiator.

[0048] Examples of alkylphenone compounds include 1-hydroxycyclohexylphenyl ketone, and examples of acylphosphine oxide compounds include 2,4,6-trimethylbenzoyl-diphenylphosphine oxide and bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide. Component (D) can be used alone or in combination of two or more. From the viewpoint of achieving both gloss and transparency, it is preferable to use alkylphenone compounds and acylphosphine oxide compounds in combination as component (D). When two or more are used in combination, the content of component (D) refers to the total amount.

[0049] In a photocurable resin composition according to one embodiment of the present invention, the content of component (D) is 0.1 to 15 parts by mass, more preferably 1 to 12 parts by mass, and even more preferably 3 to 9 parts by mass, relative to 100 parts by mass of the total content of components (A) and (B). By having component (D) within the above range relative to the total content of components (A) and (B), a photocurable resin composition with low curing heat and excellent curability can be obtained.

[0050] <(E) component> A photocurable resin composition according to one embodiment of the present invention may contain water (H2O) as component (E). The water is preferably free of impurities, and pure water is particularly preferred. Adding component (E) can further reduce the heat of curing of the photocurable resin composition.

[0051] The lower limit of the content of component (E) in the photocurable resin composition according to one embodiment of the present invention is preferably 0.001 parts by mass or more, more preferably 0.01 parts by mass or more, and even more preferably 0.1 parts by mass or more, based on 100 parts by mass of the total content of components (A) and (B). The upper limit of the content of component (E) is preferably 3 parts by mass or less, more preferably 2 parts by mass or less, and even more preferably 1.5 parts by mass or less, based on 100 parts by mass of the total content of components (A) and (B). Note that the preferred amount of addition here refers to the amount of addition including water, which is an impurity of component (C).

[0052] <Optional ingredients> A photocurable resin composition according to one embodiment of the present invention may contain additives such as polyfunctional thiol compounds, fillers, conductive fillers, silane coupling agents, plasticizers, adhesives, defoamers, pigments, rust inhibitors, leveling agents, dispersants, rheology modifiers, and flame retardants, to the extent that it does not impair the objectives of the present invention.

[0053] The photocurable resin composition according to one embodiment of the present invention preferably contains a polyfunctional thiol compound. The inclusion of a polyfunctional thiol compound promotes crosslinking, reduces oxygen inhibition on the (meth)acryloyl group, and eliminates the need to wipe off uncured material remaining on the surface of the cured product after curing. The polyfunctional thiol compound is not particularly limited as long as it contains two or more thiol groups in one molecule, but examples include 1,2-ethanedithiol, 1,2-propanedithiol, 1,3-propanedithiol, 1,3-butanedithiol, 2,3-butanedithiol, 1,5-pentanedithiol, 1,6-hexanedithiol, 1,8-octanedithiol, 1,9-nonanedithiol, 1,10-decanedithiol, 1,2-benzenedithiol, 1,3-benzenedithiol 1,4-Benzenedithiol, 3,6-Dichloro-1,2-Benzenedithiol, Toluene-3,4-Dithiol, 1,5-Naphthalenedithiol, Ethylene glycol bis(thioglycolate), Ethylene glycol bis(3-mercaptopropionate), 1,4-Butanediol bisthioglycolate, Tetraethylene glycol bis(3-mercaptopropionate), Trimethylolpropanetris(thioglycolate), Trimethylolpropanetris(3- Mercaptopropionate), trimethylolpropane tris(3-mercaptobutyrate), tris[(3-mercaptopropionyloxy)-ethyl]isocyanurate, pentaerythritol tetrakis(thioglycolate), pentaerythritol tetrakis(3-mercaptopropionate), dipentaerythritol hexakis(3-mercaptopropionate), 1,4-bis(3-mercaptobutyryloxy)butane, pentaerythritol tetrakis(3-mercaptopropionate) Putobutyrate), pentaerythritol tetrakis(3-mercaptobutyrate), 1,3,5-tris(3-mercaptobutyloxyethyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, dimercaptodiethyl sulfide, 1,8-dimercapto-3,6-dithiaoctane, 1,2-bis[(2-mercaptoethyl)thio]-3-mercaptopropane, tetrakis(7-mercapto-2,5-dithiaheptyl)methane, trithiocyanuric acid, 1,2-Benzene dimethane, thiol, 4,4'-thiobisbenzenethiol, 2-di-n-butylamino-4,6-dimercapto-s-triazine, 2-di-n-butylamino-4,6-dimercapto-s-triazine, 2,5-dimercapto-1,3,4-thiadiazole, 1,8-dimercapto-3,6-dioxaoctane, 1,5-dimercapto-3-thiapentane, tris(2-hydro)trimercaptopropionate Xyethyl) isocyanurate, 1,4-dimethylmercaptobenzene, 2,4,6-trimercapto-s-triazine, 2-(N,N-dibutylamino)-4,6-dimercapto-s-triazine, bis(4-(2-mercaptopropoxy)phenyl)methane, 1,1-bis(4-(2-mercaptopropoxy)phenyl)ethane, 2,2-bis(4-(2-mercaptopropoxy)phenyl)propane, 2,2-bis( 4-(2-mercaptopropoxy)phenyl)butane, 1,1-bis(4-(2-mercaptopropoxy)phenyl)isobutane, 2,2-bis(4-(2-mercaptopropoxy)-3-methylphenyl)propane, 2,2-bis(4-(2-mercaptopropoxy)-5-methylphenyl)propane, bis(2-(2-mercaptopropoxy)-5-methylphenyl)methane, 2,2-bis(4-(2-mercaptopropoxy) (Propoxy)-3-t-butylphenyl)propane, Tris(4-(2-mercaptopropoxy)phenyl)methane, 1,1,1-Tris(4-(2-mercaptopropoxy)phenyl)ethane, Bis(4-(2-mercaptobutoxy)phenyl)methane, 2,2-Bis(4-(2-mercaptobutoxy)phenyl)propane, Tris(4-(2-mercaptobutoxy)phenyl)methane, 1,3,5-triazine-2,4,Examples include 6-trithiol. Preferably, polyfunctional thiol compounds are obtained by reacting the hydroxyl groups inherent in trimethylolpropane, pentaerythritol, and dipentaerythritol with a compound having a thiol group or a group that reacts to form a thiol group. Particularly preferred are trimethylolpropane tris(3-mercaptopropionate), tris[(3-mercaptopropionyloxy)-ethyl]-isocyanurate, pentaerythritol tetrakis(3-mercaptopropionate), pentaerythritol tetrakis(3-mercaptobutyrate), dipentaerythritol hexakis(3-mercaptopropionate), and dipentaerythritol hexakis(3-mercaptobutyrate), with trimethylolpropane tris(3-mercaptopropionate) being the most preferred. By including these elements, the photocurable resin composition of this embodiment exhibits superior curability and storage stability.

[0054] In a photocurable resin composition according to one embodiment of the present invention, the content of the polyfunctional thiol compound is preferably 0.1 to 30 parts by mass, more preferably 3 to 25 parts by mass, and even more preferably 5 to 20 parts by mass, based on 100 parts by mass of the total content of component (A) and component (B). By having the content of the polyfunctional thiol compound within the above range, a photocurable resin composition with low curing heat and excellent curability can be obtained.

[0055] A photocurable resin composition according to one embodiment of the present invention may contain fillers to the extent that the objectives of the present invention are not impaired, in order to improve the elastic modulus, fluidity, and other properties of the cured product. Specific examples of fillers include inorganic powders and organic powders.

[0056] 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, and kaolin. These may be used individually or in combination of two or more. The inorganic powder content in the photocurable resin composition according to one embodiment of the present invention is preferably about 0.1 to 200 parts by mass per 100 parts by mass of component (A).

[0057] Fumed silica is added to photocurable resin compositions for the purpose of adjusting the viscosity or improving the mechanical strength of the cured product. Preferably, fumed silica surface-treated with dimethylsilane, trimethylsilane, alkylsilane, methacryloxysilane, organochlorosilane, polydimethylsiloxane, hexamethyldisilazane, etc. is used. Examples of commercially available fumed silica include, but are not limited to, Aerosil 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, R7200, etc. (manufactured by Nippon Aerosil Co., Ltd.). These can be used individually or in combination of two or more types.

[0058] Examples of organic powder fillers include, but are not limited to, polyethylene, polypropylene, polystyrene, nylon, polyester, polyvinyl alcohol, polyvinyl butyral, polycarbonate, and polymethyl (meth)acrylate. These may be used individually or in combination of two or more. The content of the organic powder in the photocurable resin composition according to one embodiment of the present invention is preferably 0.1 to 200 parts by mass per 100 parts by mass of component (A).

[0059] A photocurable resin composition according to one embodiment of the present invention may contain conductive fillers. Examples include, but are not limited to, gold, silver, platinum, nickel, palladium, and plated particles in which a thin metal film is coated on organic polymer particles. These may be used individually or in combination of two or more.

[0060] A photocurable resin composition according to one embodiment of the present invention may contain a silane coupling agent. Examples of silane coupling agents include, but are not limited to, 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. These silane coupling agents may be used alone or in combination of two or more. The content of the silane coupling agent in the photocurable resin composition according to one embodiment of the present invention is preferably 0.05 to 30 parts by mass, and more preferably 0.2 to 10 parts by mass, based on the content of component (A) per 100 parts by mass.

[0061] In this invention, "artificial nail" refers to a layer formed on a human or animal nail for decorative and / or protective purposes. For example, artificial nails also include resin base materials (false nails) of any shape intended for decorative and / or protective purposes. The shape of the artificial nail is not particularly limited; it may be formed to cover the nail, or it may be formed in a shape larger than the nail for the purpose of extending the nail. It may also be formed for the purpose of adhering items (decorative items) such as stones to the nail to improve its appearance.

[0062] Another embodiment of the present invention is a cured product (cured product of a photocurable resin composition) obtained by curing the above-described photocurable resin composition. Here, specific examples of cured products include a base coat layer, a color layer, and a top coat layer used in nail color art.

[0063] Artificial nails generally have a structure in which a base coat layer (a layer intended to provide adhesion to the nail and prevent color transfer), a color layer (a layer containing colorants and intended for decoration), and a top coat layer (a layer intended for coating, providing gloss, and improving aesthetics) are layered in this order. Furthermore, the formation method involves first forming a base coat layer on the nail surface by curing a photocurable resin composition for the base coat, then forming a color layer on top of that by curing a photocurable resin composition for the color, and finally forming a top coat layer on top of that by curing a photocurable resin composition for the top coat. The photocurable resin composition according to the present invention is suitable for use as a base coat layer applied to the nail surface because it generates little heat during curing. In addition, when applying and curing a top coat layer to improve its appearance, the resin layer may be applied and cured to increase its thickness, but because this photocurable resin composition generates little heat during curing, even if the curing amount increases in this way, pain due to the heat of curing is less likely to be felt. For this reason, it is also suitable for use as a top coat layer.

[0064] A preferred example of a method for covering (decorating) nails or artificial nails according to the present invention is shown below, but the method according to the present invention is not limited to this method.

[0065] Before applying the photocurable resin composition according to the present invention directly to the nail, it is preferable to sand the nail surface with a file or the like to improve adhesion, and then remove dust, oil, moisture, etc. with a nail-specific solvent mainly composed of ethanol. When applying the photocurable resin composition according to the present invention, a coating film with a thickness of 50 to 300 μm in the pre-curing state is formed using a brush or similar tool. Alternatively, it may be applied directly on top of the cured film of the base coat resin or color resin. A primer may be used beforehand when applying. A commercially available nail UV lamp or nail LED lamp is used as the irradiation device for curing. The irradiation time is preferably 15 to 120 seconds, and more preferably 20 to 70 seconds considering the effect on the fingers. The cumulative light intensity is 300 to 1,500 mJ / cm². 2 Preferably, the concentration is 500-1,000 mJ / cm². 2 It is more preferable that this is the case. Furthermore, when the photocurable resin composition for the topcoat is cured, a step may be provided to wipe the surface of the cured product with an organic solvent or the like in order to remove stickiness and make the gloss look beautiful.

[0066] The photocurable resin composition of the present invention can be manufactured by conventionally known methods. For example, it can be manufactured by mixing components (A) to (D), and optionally a predetermined amount of other components, using a mixing means such as a planetary mixer, under light-shielding conditions at a temperature preferably of 10 to 50°C for preferably 0.1 to 5 hours.

[0067] <Methods for covering (decorating) natural or artificial nails> Another embodiment of the present invention is a method for coating a nail or artificial nail, comprising applying the above-mentioned photocurable resin composition to a nail or artificial nail to form a coating film, and then curing the coating film by irradiating it with active energy rays. In this specification, "applying to a nail or artificial nail" includes applying it directly to the surface of a human nail (natural nail) or an artificial nail (nail tip), or applying it on top of one or more other layers formed on the surface of a human nail or artificial nail. [Examples]

[0068] 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 examples, unless otherwise specified, the operations were carried out at room temperature (25°C).

[0069] <Preparation of photocurable resin composition> Each of the components listed below was taken in the proportions (parts by mass) shown in Table 1 and mixed for 60 minutes using a planetary mixer at 25°C under light-shielding conditions to prepare a photocurable resin composition. Details of each component are as follows. Note that the proportion of component (C) shown in Table 1 includes component (E) (water), which is present as an impurity in commercially available products. For example, the photocurable resin composition of Example 1 contains component c1 at a proportion of 6.15% by weight, of which 9-11% is water, which is component (E).

[0070] (A) component a1: Trifunctional alicyclic urethane acrylate oligomer (ART RESIN® KY-11 (85% by weight of KY-11 is the trifunctional alicyclic urethane acrylate oligomer when the total amount of KY-11 is 100% by weight), manufactured by Negami Kogyo Co., Ltd., weight-average molecular weight: 5,000) 《(B) Component》 b1: Tripropylene glycol diacrylate (ART RESIN® KY-11 (15% by weight of KY-11 is tripropylene glycol diacrylate when the total amount of KY-11 is 100% by weight), manufactured by Negami Kogyo Co., Ltd.) b2: Dimethylol-tricyclodecanediaacrylate (Light Acrylate® DCP-A, manufactured by Kyoeisha Chemical Co., Ltd.) b3: 2-Hydroxypropyl methacrylate (Acrylic ester HP, manufactured by Mitsubishi Rayon Co., Ltd.) 《(C) Component》 c1: Polyglycerin (Polyglycerin #750, manufactured by Sakamoto Pharmaceutical Co., Ltd., molecular weight: 758, contains 9-11% water and 5% or less glycerin) c2: Polyglycerin (Polyglycerin #310, manufactured by Sakamoto Pharmaceutical Co., Ltd., molecular weight: 314, contains 4-6% water and 5-15% glycerin) c3: Polyglycerin (Polyglycerin 20PW, manufactured by Daicel Corporation, molecular weight: 1602, contains 10.1% water, no glycerin content) c4: Polyglycerin (Polyglycerin XPW, manufactured by Daicel Corporation, molecular weight: 3222, contains 9.9% water, no glycerin content) c5: Polyoxyethylene polyglyceryl ether (SC-E750, manufactured by Sakamoto Pharmaceutical Co., Ltd., weight-average molecular weight: 750, contains 0.11% water, no glycerin content) c6: Polyoxypropylene polyglyceryl ether (SC-P750, manufactured by Sakamoto Pharmaceutical Co., Ltd., weight-average molecular weight: 750, contains 0.05% water, no glycerin content) (C') component is a comparative example of (C) component. c'1: Diglycerin (Diglycerin 801, manufactured by Sakamoto Pharmaceutical Co., Ltd., molecular weight: 166, contains 0.1% water and 1.0% glycerin) c'2: Polyglycerin skeleton hexafunctional acrylate (SA-TE6, manufactured by Sakamoto Pharmaceutical Co., Ltd., weight-average molecular weight: 1,000, no water or glycerin content) 《(D)Component》 d1: 1-Hydroxycyclohexylphenyl ketone (DOUBLECURE® 184, manufactured by Double Bond Chemical) d2: 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (DOUBLECURE® TPO, manufactured by Double Bond Chemical) 《(E) Component》 e1: Water (purified water, manufactured by Kyoei Pharmaceutical Co., Ltd.) Polyfunctional thiol compounds Trimethylolpropanetris (3-mercaptopropionate) (TMMP-20P, manufactured by SC Organic Chemicals Co., Ltd.) The test methods used in the examples and comparative examples in Table 1 are as follows:

[0071] <Measurement of curing heat reduction rate> Differential scanning calorimetry (DSC) was performed during irradiation with active energy rays. 0.5 mg of each of the photocurable resin compositions listed in Table 1 was weighed into an aluminum sample pan. The sample pans were placed in their designated positions within the measuring instrument, and an empty sample pan was also placed in its designated position for reference. A quartz cell was placed between the sample pan and the high-pressure mercury lamp. The measurement environment was set to 25°C at the start of the measurement. After standing at 25°C for 1 minute, the sample was irradiated with a 3 mW high-pressure mercury lamp for 3 minutes, and finally stood at 25°C for 1 minute, for a total measurement time of 5 minutes. The lower the maximum value of the DSC peak (μW) (differential scanning calorimetry: change in heat flow due to endothermic and exothermic reactions of the sample), the less heat is perceived in the sensory test described below. A photocurable resin composition X and a resin composition Y that does not contain component (C) in resin composition X were prepared, and when the maximum DSC peak value of resin composition X was α (mW) and the maximum DSC peak value of resin composition Y was β (mW), the curing heat reduction rate (%) was defined as 100 - (α / β × 100). In the present invention, a curing heat reduction rate of greater than 5% is preferable, greater than 7% is more preferable, even preferable than 9% is preferable, and most preferable is greater than 13%.

[0072] In other words, in a photocurable resin composition according to one embodiment of the present invention, it is preferable that the maximum DSC peak value of the photocurable resin composition X of the present invention, α (mW), and the maximum DSC peak value of the resin composition Y having a composition obtained by removing component (C) from the composition of the photocurable resin composition X, satisfy the following formula (4).

[0073]

number

[0074] <Sensory Testing> After degreasing the surface of the fingernails of a human body, the photocurable resin compositions shown in Table 1 were applied to a thickness of 100 μm, and then cured using a nail LED lamp (Lexia EX 30W, wavelength 395-405 nm) (curing conditions: irradiation time 30 seconds, integrated light intensity 750 mJ / cm²).2 The evaluation was conducted on the fingernails of three people, and the "heat generated during curing" was checked according to the following evaluation criteria. A "○" is preferable for no heat to be felt on the fingernails of a human body.

[0075] ≪Evaluation Criteria≫ ○: Two or more people do not feel their fingernails are hot. ×: Two or more people feel the nails are hot.

[0076] <Viscosity measurement> 0.5 mL of each photocurable resin composition from Table 1 was taken and dispensed into a measuring cup. Viscosity was measured using an EHD type viscometer (manufactured by Toki Sangyo Co., Ltd.) under the following conditions. The results were defined as "viscosity (Pa·s)". When coating (decorating) nails, a viscosity of 0.5 to 150 Pa·s is preferable from the viewpoint of workability, such as suppression of composition flow and ease of application.

[0077] ≪Evaluation Criteria≫ ○: 0.5~150 Pa·s ×: Less than 0.5 Pa·s or greater than 150 Pa·s <Measurement Conditions> Cone rotor: 3° × R14 Rotation speed: 1 rpm Measurement time: 3 minutes Measurement temperature: 25°C (temperature controlled by a constant temperature bath).

[0078] <Hardness measurement> A 1mm thick spacer was placed on a 1.0 x 150 x 150mm blue glass plate, and resin was applied. A PET film was placed on top of that, and then another blue glass plate was placed on top, sandwiching the resin. Curing conditions: High-pressure mercury lamp (cumulative light intensity 30kJ / m²) 2Using a UV meter, two sheets of blue glass were irradiated twice from the front and back surfaces to create a 1mm thick cured material (the UV light passing through the PET film and blue glass was adjusted to meet the curing conditions described above). Three cured materials were created in the same manner and left for 2 hours. After that, the blue glass and PET film were peeled off, and the three 1mm thick sheet-like cured materials were stacked with the side where the PET film was attached facing upwards. The hardness of the stacked sheet-like cured materials was measured on a smooth surface using a Type D durometer tester. Five measurements were taken, and the average of the three measurements excluding the maximum and minimum values ​​was calculated. For the cured material to be resistant to scratches and peeling in daily life, a hardness of 70 or higher is preferable.

[0079] ≪Evaluation Criteria≫ ○: D70 or higher ×: Less than D70 <Measurement Conditions> Durometer pressing speed: 3.0 mm / sec Numerical reading method: The maximum value within 1 second after the tip of the durometer's measuring part comes into close contact with the object being measured.

[0080] [Table 1]

[0081] Table 1 shows that the photocurable resin composition does not produce heat during curing. While the content of component (C) differs between Example 1 and Example 2, and between Example 1 and Examples 3-7, all exhibit a high reduction in heat generation during curing and are photocurable resin compositions that do not produce heat in sensory tests. Furthermore, the viscosity range is suitable for application to nails, and the cured product is sufficiently hard, making it suitable for application to human nails.

[0082] According to the comparative examples in Table 1, Comparative Example 1 did not contain component (C), so the reduction in curing heat was 0%, and the sensory test resulted in a feeling of heat. In Comparative Example 2, c'1 is diglycerin with a molecular weight of less than 200, but it was found to have a counterproductive effect on reducing curing heat. In Comparative Examples 3 and 4, c'2 is a compound having a polyglycerin skeleton and a methacryloyl group, but it did not contribute to the reduction in curing heat, and the sensory test resulted in a feeling of heat. [Industrial applicability]

[0083] The photocurable resin composition of the present invention has low curing heat, a viscosity range useful for application to nails, and a sufficiently hard cured product, making it widely usable in the nail industry.

[0084] This application is based on Japanese Patent Application No. 2021-12014, filed on 28 January 2021, the disclosures of which are referenced and incorporated in whole.

Claims

1. A photocurable resin composition for nails or artificial nails comprising the following components (A) to (D) and a polyfunctional thiol compound, wherein the molecular weight of component (C) is 200 or more; (A) Ingredients: Urethane (meth)acrylate oligomer (B) Component: A monomer selected from the group consisting of (meth)acrylate monomer, (meth)acrylamide monomer, and (meth)acrylic acid (excluding component (A)). (C) Component: Polyglycerin without a (meth)acryloyl group and / or a compound having a polyglyceryl ether skeleton without a (meth)acryloyl group. (D) Component: Photoinitiator.

2. The photocurable resin composition for nails or artificial nails according to claim 1, wherein the molecular weight of component (C) is 200 or more and 5,000 or less.

3. The photocurable resin composition for nails or artificial nails according to claim 1 or 2, wherein the (C) component is polyglycerin without a (meth)acryloyl group and / or polyoxyalkylene polyglyceryl ether without a (meth)acryloyl group.

4. The photocurable resin composition for nails or artificial nails according to any one of claims 1 to 3, further comprising water as component (E).

5. The photocurable resin composition for nails or artificial nails according to any one of claims 1 to 4, wherein the (D) component is an acylphosphine oxide-based photoinitiator and / or an alkylphenone-based photoinitiator.

6. A photocurable resin composition for nails or artificial nails according to any one of claims 1 to 5, comprising 10 to 200 parts by mass of component (B) per 100 parts by mass of component (A), 0.1 to 50 parts by mass of component (C) and 0.1 to 15 parts by mass of component (D) per 100 parts by mass of component (A) and component (B).

7. The photocurable resin composition for nails or artificial nails according to any one of claims 1 to 6, wherein the polyfunctional thiol compound is one or more selected from the group consisting of trimethylolpropane tris(3-mercaptopropionate), tris[(3-mercaptopropionyloxy)-ethyl]-isocyanurate, pentaerythritol tetrakis(3-mercaptopropionate), pentaerythritol tetrakis(3-mercaptobutyrate), dipentaerythritol hexakis(3-mercaptopropionate), and dipentaerythritol hexakis(3-mercaptobutyrate).

8. A photocurable resin composition for nails or artificial nails according to any one of claims 1 to 7, satisfying the following conditions: A photocurable resin composition X for nails or artificial nails and a resin composition Y that does not contain component (C) in resin composition X are prepared, and the maximum DSC peak value of resin composition X: α (mW) and the maximum DSC peak value of resin composition Y: β (mW) are both 100 - (α / β × 100) > 5%.

9. A cured product obtained by curing a photocurable resin composition for nails or artificial nails according to any one of claims 1 to 8.

10. A method for coating a nail or artificial nail, comprising applying a photocurable resin composition for nails or artificial nails according to any one of claims 1 to 8 to a nail or artificial nail to form a coating film, and then curing the coating film by irradiating it with active energy rays.

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