Photocurable resin composition for nail or artificial nail, cured product, and method for covering nail or artificial nail

Abstract

The present invention provides a photocurable resin composition for nail or artificial nail with low curing heat. A photocurable resin composition for nail or artificial nail, comprising the following (A) to (D) components, the molecular weight of the (C) component being 200 or more, (A) component: urethane (meth) acrylate oligomer; (B) component: monomer (other than the (A) component) selected from the group consisting of (meth) acrylate monomer, (meth) acrylamide monomer, and (meth) acrylic acid; (C) component: polyglycerol having no (meth) acryloyl group, and / or a compound having a polyglycerol ether skeleton not containing a (meth) acryloyl group; (D) component: photoinitiator.

Description

Technical Field

[0001] This invention relates to a light-curing resin composition suitable for covering nails or artificial nails, a cured product, and a method for covering nails or artificial nails. Background Technology

[0002] Previously, in the nail industry, there were known light-curing resin compositions (UV nail gels) containing photopolymerizable monomers and / or oligomers. These UV nail gels were applied to the nails using a brush or similar tool, and then cured by irradiation with light to create a glossy, beautiful nail film with excellent adhesion to the nail. Because this process involves curing the resin directly onto the nail, the curing heat is directly transferred to the nail, sometimes causing pain. Therefore, there has always been a demand for resins with low curing heat.

[0003] Japanese Patent Application Publication No. 2020-12015 discloses a photocurable resin composition having a heating temperature below 55°C during the curing process, comprising a urethane (meth)acrylate resin having a polytetramethylene glycol backbone and 2 to 5 functional groups, a (meth)acrylate monomer, a polyether-modified polysiloxane copolymer, and a photopolymerization initiator. Summary of the Invention

[0004] The inventors of this invention have conducted in-depth research on light-curing resin compositions for nails or artificial nails with low curing heat, as described in Japanese Patent Application Publication No. 2020-12015.

[0005] Therefore, the object of the present invention is to provide a light-curing resin composition for nails or artificial nails with low curing heat.

[0006] Another object of the present invention is to provide a photocurable resin composition that yields a cured product with sufficient hardness.

[0007] The key points of this invention are described below.

[0008] [1] A light-curing resin composition for nails or artificial nails, comprising components (A) to (D) below, wherein component (C) has a molecular weight of 200 or more.

[0009] (A) Ingredients: Carbamate (meth)acrylate oligomers;

[0010] (B) Ingredients: (A) are selected from monomers of (meth)acrylate, (meth)acrylamide and (meth)acrylic acid, but do not include ingredient (A);

[0011] (C) Ingredients: Polyglycerol without (meth)acryloyl groups, and / or compounds having a polyglycerol ether backbone without (meth)acryloyl groups;

[0012] (D) Component: Photoinitiator.

[0013] [2] The light-curing resin composition for nails or artificial nails according to [1], wherein the molecular weight of component (C) is 200 or more and 5000 or less.

[0014] [3] The light-curing resin composition for nails or artificial nails according to [1] or [2], wherein the (C) component is polyglycerol without (meth)acryloyl and / or polyoxyethylene polyglycerol ether without (meth)acryloyl.

[0015] [4] The light-curing resin composition for nails or artificial nails according to any one of [1] to [3], wherein water is further contained as component (E).

[0016] [5] A light-curing resin composition for nails or artificial nails according to any one of [1] to [4], wherein the component (D) is an acylphosphine oxide photoinitiator and / or an alkyl phenyl ketone photoinitiator.

[0017] [6] A light-curing resin composition for nails or artificial nails according to any one of [1] to [5], wherein, relative to 100 parts by weight of component (A), it comprises 10 to 200 parts by weight of component (B), and relative to 100 parts by weight of components (A) and (B), it comprises 0.1 to 50 parts by weight of component (C) and 0.1 to 15 parts by weight of component (D).

[0018] [7] The light-curing resin composition for nails or artificial nails according to any one of [1] to [6], wherein it further contains a polyfunctional thiol compound.

[0019] [8] The light-curing resin composition for nails or artificial nails according to any one of [1] to [7] satisfies the following conditions.

[0020] The above-mentioned light-curable resin composition X for nails or artificial nails and resin composition Y which does not contain component (C) were prepared respectively. The maximum DSC peak value α (mW) of resin composition X and the maximum DSC peak value β (mW) of resin composition Y satisfy 100-(α / β×100)>5%.

[0021] [9] A cured product obtained by curing any one of the nails or artificial nails described in any one of [1] to [8] with a light-curing resin composition.

[0022]

[10] A method for covering a nail or artificial nail, comprising the following steps: applying a light-curing resin composition to the nail or artificial nail as described in any one of [1] to [8] to form a coating film, and then irradiating the coating film with active energy rays to cure the coating film. Detailed Implementation

[0023] The following describes embodiments of the invention. However, this disclosure is not limited to these embodiments. In this specification, "X to Y" refers to a range including the lower and upper limits of the values ​​(X and Y) described before and after it. Unless otherwise specified, "%" for concentration indicates mass concentration, i.e., "mass %", and "ratio" refers to mass ratio unless otherwise specified. Unless otherwise specified, measurements of operation and physical properties are performed at room temperature (20-25°C) and relative humidity 40-50%RH. "A and / or B" specifically refers to at least one of A and B, and also to A, B, and combinations of A and B.

[0024] <Light-curing resin compositions for nails or artificial nails>

[0025] An embodiment of the present invention provides a light-curing resin composition for artificial nails (hereinafter also referred to as "light-curing resin composition" or simply "composition") comprising the following components (A) to (D), wherein component (C) has a molecular weight of 200 or more.

[0026] (A) Ingredients: Carbamate (meth)acrylate oligomers;

[0027] (B) Ingredients: Selected from (meth)acrylate monomers, (meth)acrylamide monomers and (meth)acrylic acid monomers (excluding (A) ingredient);

[0028] (C) Ingredients: Polyglycerol without (meth)acryloyl groups and / or compounds with a polyglycerol ether backbone without (meth)acryloyl groups;

[0029] (D) Component: Photoinitiator.

[0030] According to one aspect of the present invention, a light-curing resin composition for nails or artificial nails with low curing heat can be provided. Furthermore, the light-curing resin composition of one aspect of the present invention has a viscosity suitable for application to nails and artificial nails. Moreover, the light-curing resin composition of one aspect of the present invention can yield a cured product with sufficient hardness (hardness) as a coating for nails and artificial nails.

[0031] <(A)Component>

[0032] The photocurable resin composition of the present invention contains component (A) as a urethane (meth)acrylate oligomer. A urethane (meth)acrylate oligomer refers to an oligomer having one or more urethane bonds and (meth)acryloyl groups. Adding a urethane (meth)acrylate oligomer can improve the adhesion to nails or artificial nails, and improve the curing properties and strength of the photocurable resin composition (coating). Furthermore, in this specification, the urethane (meth)acrylate oligomer may have a (meth)acryloyl group as a (meth)acryloyloxy group. Additionally, the term "(meth)acryloyl" includes both acryloyl and methacryloyl groups. Therefore, for example, the term "(meth)acryloyl" includes an acryloyl group (H... ２ C=CH-C(=O)-) and methacryloyl (H) ２ C = C(CH) ３ Both )-C (=O)-). Similarly, the term "(meth)acrylate" includes both acrylate and methacrylate, and the term "(meth)acrylic acid" includes both acrylic acid and methacrylic acid. Additionally, "oligomer" refers to polymers with monomer units repeating from 2 to several tens.

[0033] (A) is not particularly limited as long as it is an oligomer having one or more urethane bonds and (meth)acryloyl groups, but preferably contains 2 to 6 (meth)acryloyl groups, more preferably 2 to 3, and even more preferably 3. The presence of 2 to 6 (meth)acryloyl groups helps to reduce the curing heat of this photocurable resin composition. Furthermore, the (meth)acryloyl group in (A) is preferably an acryloyl group. In addition to urethane bonds and (meth)acryloyl groups, it may also have other functional groups such as carboxyl groups, phosphate groups, epoxy groups, and hydroxyl groups.

[0034] (A) The weight-average molecular weight of the oligomer of component (A) is preferably 1,000 to 100,000, more preferably 2,000 to 70,000. Within this range, a viscosity with good workability can be maintained, while also ensuring good curability of the cured product. Furthermore, in this specification, the weight-average molecular weight is a value determined by gel permeation chromatography (GPC) using polystyrene as a standard.

[0035] For urethane (meth)acrylate oligomers having urethane bonds, urethane bonds can be formed by reacting a polyol with a polyisocyanate, and then a compound having hydroxyl and (meth)acryloyl groups or (meth)acrylic acid can be added to an unreacted isocyanate group to synthesize the oligomer. However, the method of synthesizing the (meth)acrylate oligomer is not limited to this method. The urethane (meth)acrylate oligomer preferably has a polyalkylene glycol backbone, more preferably a polypropylene glycol backbone. Having a polyalkylene glycol backbone improves the adhesion to the nail or artificial nail. Furthermore, the urethane (meth)acrylate oligomer preferably has a cyclic structure, more preferably an alicyclic structure. Additionally, the cyclic structure preferably has two or more rings, more preferably two. By giving the urethane (meth)acrylate oligomer a cyclic structure, the curability and strength of the photocurable resin composition of the present invention can be improved.

[0036] Specific examples of commercially available products containing ingredient (A) above include AH-600 (phenyl glycidyl ether acrylate hexamethylene diisocyanate carbamate prepolymer with 2 (meth)acryloyl groups), AT-600 (phenyl glycidyl ether acrylate toluene diisocyanate carbamate prepolymer with 2 (meth)acryloyl groups), UA-306H (pentaerythritol triacrylate hexamethylene diisocyanate carbamate prepolymer with 2 (meth)acryloyl groups), UF-8001G (non-yellowing oligomeric carbamate acrylate with 2 (meth)acryloyl groups) (manufactured by Kyoei Chemical Co., Ltd.), or RUA-071 (6-functional carbamate acrylate with 6 (meth)acryloyl groups), RUA-003VE (15-functional carbamate acrylate). Esters, having 15 (meth)acryloyl groups), RUA-075 (5-functional urethane acrylate with 5 (meth)acryloyl groups), RUA-048 (3-functional urethane acrylate with 3 (meth)acryloyl groups) (manufactured by Asia Chemical Industry Co., Ltd.), UN-9200A (polycarbonate-based difunctional urethane acrylate with 2 (meth)acryloyl groups), UN-9000PEP (polycarbonate-based difunctional urethane acrylate with 2 (meth)acryloyl groups), UN-7700 (polyester-based difunctional urethane acrylate with 2 (meth)acryloyl groups), KY-11 (polyether-based trifunctional urethane acrylate with 3 (meth)acryloyl groups) (manufactured by Negami Kogyo Co., Ltd.), etc., but not limited to these.

[0037] <(B) Ingredients>

[0038] The photocurable resin composition of the present invention includes component (B) which is selected from monomers of (meth)acrylate, (meth)acrylamide, and (meth)acrylic acid (excluding component (A)). There are no particular limitations on the (meth)acrylate monomers and (meth)acrylamide monomers; known monomers can be used. Preferably, the monomers used as component (B) are monofunctional, difunctional, or trifunctional monomers. Furthermore, component (B) preferably comprises a combination of multiple monomers with different numbers of functional groups, and more preferably, it comprises monofunctional and difunctional monomers. By including multiple monomers with different numbers of functional groups in component (B), it is possible to improve the adhesion to the nail or artificial nail.

[0039] In one embodiment of the present invention, the content of component (B) in the photocurable resin composition (in the case where two or more monomers are used as component (B), it refers to their total amount) is preferably in the range of 10 to 200 parts by mass relative to the content of component (A), more preferably 15 to 150 parts by mass. By being within the above range, the photocurable resin composition of the present invention can yield a cured product with strong toughness and excellent adhesion.

[0040] Specific examples of monofunctional (meth)acrylate monomers include lauryl (meth)acrylate, octadecyl (meth)acrylate, ethyl carbitol (meth)acrylate, tetrahydrofuran meth(meth)acrylate, caprolactone-modified tetrahydrofuran meth(meth)acrylate, cyclohexyl (meth)acrylate, dicyclopentyl (meth)acrylate, isobornyl (meth)acrylate, benzyl (meth)acrylate, phenyl (meth)acrylate, phenoxyethyl (meth)acrylate, and phenoxydiethylene glycol (meth)acrylate. Phenoxytetraethylene glycol (meth)acrylate, Nonylphenoxyethyl methacrylate, Nonylphenoxytetraethylene glycol (meth)acrylate, Methoxydiethylene glycol (meth)acrylate, Ethoxydiethylene glycol (meth)acrylate, Butoxyethyl methacrylate, Butoxytriethylene glycol (meth)acrylate, 2-Ethylhexyl polyethylene glycol (meth)acrylate, 4-Hydroxybutyl methacrylate, Nonylphenyl polypropylene glycol (meth)acrylate, Methoxydipropylene glycol (meth)acrylate, 2-Hydroxyethyl methacrylate, 2-Hydroxypropyl (meth)acrylate, Glyceryl (meth)acrylate, Polyethylene glycol (meth)acrylate, Polypropylene glycol (meth)acrylate, Epichlorohydrin-modified butyl (meth)acrylate, Epichlorohydrin-modified phenoxy (meth)acrylate, N,N-Dimethylamino (meth)acrylate, N,N-Diethylamino (meth)acrylate, 3-(meth)acryloyloxypropyl succinic acid, 4-(meth)acryloyloxybutyl succinic acid, 2-(meth)acryloyloxyethyl maleic acid, 3-(meth)acryloyloxyethyl maleic acid 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, 2-hydroxyethyl methacrylate phosphate, etc., but not limited to these.

[0041] Among these, the monofunctional (meth)acrylate monomer preferably includes a monofunctional (meth)acrylate monomer having a hydroxyl group. Specific examples of the hydroxyl-containing monofunctional (meth)acrylate monomer include 2-hydroxyethyl (meth)acrylate and 2-hydroxypropyl (meth)acrylate, but it is not limited to these. The hydroxyl-containing monofunctional (meth)acrylate monomer is preferably 2-hydroxypropyl (meth)acrylate, and more preferably 2-hydroxypropyl methacrylate. The hydroxyl-containing monofunctional monomer can be a commercially available product; specific examples of commercially available products include Acrylates HP (registered trademark) manufactured by Mitsubishi Rayon Co., Ltd., but it is not limited to these.

[0042] Specific examples of difunctional (meth)acrylate monomers include 1,3-butanediol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, tricyclodecanediethanol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,6-hexanediol 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, and ethylene oxide-modified neopentyl glycol di(meth)acrylate. Acrylic esters, propylene 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 triisocyanate, dimethyloltricyclodecanoic acid di(meth)acrylate, etc., but not limited to these.

[0043] Specific examples of trifunctional (meth)acrylate monomers include 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, tri(acryloyloxyethyl)tripolyisocyanate, etc., but are not limited to these.

[0044] Specific examples of (meth)acrylamide monomers include (meth)acrylamide, N-methyl (meth)acrylamide, N-ethyl (meth)acrylamide, N-propyl (meth)acrylamide, N-n-butyl (meth)acrylamide, N-tert-butyl (meth)acrylamide, N-butoxymethyl (meth)acrylamide, N-isopropyl (meth)acrylamide, N-hydroxymethyl (meth)acrylamide, N,N-dimethyl (meth)acrylamide, (meth)acryloylmorpholine, N,N-diethyl (meth)acrylamide, N-methyl-N-ethyl (meth)acrylamide, N-hydroxyethyl (meth)acrylamide, etc., but are not limited to these.

[0045] <(C) Ingredients>

[0046] The photocurable resin composition of the present invention includes component (C) which is a polyglycerol without a (meth)acrylyl group and / or a compound with a polyglycerol ether backbone without a (meth)acrylyl group, having a molecular weight of 200 or more. Component (C) can be a compound represented by formula (1) and / or formula (2). By using component (C), the curing heat of the photocurable resin composition can be reduced. One or more components (C) can be used.

[0047] Polyglycerol without (meth)acryloyl groups can be as shown in formula (1). Here, n in formula (1) is preferably an integer of 3 or more, and from the viewpoint of reducing the curing heat of the photocurable resin composition, n is more preferably an integer of 3 to 45.

[0048] [Chemical Formula 1]

[0049]

[0050] Polyglycerols without (meth)acryloyl groups can be commercially available. Specific examples of commercially available products include polyglycerol #310, #500, #750 (manufactured by Sakamoto Pharmaceutical Co., Ltd.), polyglycerol 20PW, and polyglycerol XPW (manufactured by Daicel Co., Ltd.).

[0051] Compounds having a polyglycerol ether backbone without (meth)acryloyl groups can be as shown in formula (2). Where m is an integer greater than or equal to 1, R... 1 These are the groups that are shown independently in equation (3). In equation (3), p is an integer greater than or equal to 0 or 1, and R... 3 It is hydrogen or alkyl, R 2 It is an alkylene group. In formula (2), it contains at least one molecule with p=1 or more and / or p=0, and R... 3 R is an alkyl group 1 That is, R in equation (2) 1 At least one of the groups shown is in formula (3) where p is 1 or more and / or p is 0, and R 3 It is an alkyl group.

[0052] [Chemical Formula 2]

[0053]

[0054] [Chemical Formula 3]

[0055]

[0056] As long as the molecular weight of the compound having a polyglycerol ether backbone without (meth)acryloyl groups is 200 or more, m in formula (2) can be an integer of 1 or more, without particular limitation. From the viewpoint of helping to reduce curing heat, m in formula (2) is preferably an integer of 2 or more, and more preferably m is 2.

[0057] The total number of p in formula (3) contained in one molecule of a compound having a polyglycerol ether backbone without (meth)acryloyl groups is preferably 2 to 45, more preferably 3 to 35, further preferably 4 to 25, and particularly preferably 5 to 15. When the total number of p is in the range of 2 to 45, it can further contribute to the reduction of curing heat.

[0058] Compounds having a polyglycerol ether backbone without (meth)acrylyl groups can be polyoxyalkylene polyglycerol ethers without (meth)acrylyl groups. More preferably, such polyoxyalkylene polyglycerol ethers contain at least one alkylene oxide (p is an integer greater than or equal to 1, R) per molecule. 3 (For hydrogen). The polyoxyethylene polyglycerol ether is further preferably containing at least one ethylene oxide moiety (p is an integer greater than or equal to 1, R) in one molecule. 2 It is ethylene, R 3 Polyethylene polyglycerol ether containing hydrogen (p is an integer greater than or equal to 1), or containing at least one propylene oxide molecule (p is an integer greater than or equal to 1, R is a hydrogen molecule). 2 It is propylidene, R 3 Polyoxypropylene polyglycerol ether (containing hydrogen).

[0059] Compounds having a polyglycerol ether backbone without (meth)acryloyl groups can be commercially available. Specific examples of commercially available products include SC-P750, SC-P1000, SC-P1600, SC-E750, SC-E1000, SC-E1500, and SC-E2000 (manufactured by Sakamoto Pharmaceutical Co., Ltd.).

[0060] Additionally, commercially available products that can be used as ingredient (C) above contain 0-15% water and / or 0-20% glycerol as impurities. However, the content of ingredient (C) described later does not include the content of water and glycerol, which can be present as impurities. Furthermore, water, which is present as an impurity in commercially available products that can be used as ingredient (C), is also present in ingredient (E).

[0061] The molecular weight of component (C) is 200 or more, preferably 250 or more, and more preferably 290 or more. Furthermore, there is no particular upper limit to the molecular weight of component (C), but it is preferably 5000 or less, and more preferably 3500 or less. Additionally, the molecular weight of component (C) is a value calculated theoretically, but if it cannot be derived from a calculation, it may be a weight-average molecular weight value.

[0062] The content of component (C) in the photocurable resin composition of the present invention (the total amount when containing two or more components) is preferably 0.1 to 50 parts by mass relative to the total content of components (A) and (B) of 100 parts by mass, more preferably 1 to 35 parts by mass, further preferably 3 to 25 parts by mass, and particularly preferably 7 to 20 parts by mass. By ensuring that the content of component (C) is 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.

[0063] <(D) Components>

[0064] According to one aspect of the present invention, the photocurable resin composition contains a photoinitiator (photopolymerization initiator) as component (D). Examples of photoinitiators as component (D) include free radical photoinitiators that generate free radical species by irradiation with active energy rays such as visible light, ultraviolet light, X-rays, and electron beams; cationic photoinitiators that generate cationic species; and anionic photoinitiators that generate anionic species, with free radical photoinitiators being preferred.

[0065] Examples of free radical photoinitiators include alkyl phenyl ketone compounds, acylphosphine oxide compounds, titanoceramic compounds, oxime ester compounds, benzoin compounds, acetophenone compounds, benzophenone compounds, thioxanthone compounds, α-acyl oxime ester compounds, phenylglyoxylate compounds, azo compounds, diphenyl sulfide compounds, organic pigment compounds, iron-phthalocyanine compounds, benzoin ether compounds, and anthraquinone compounds. From a reactivity perspective, alkyl phenyl ketone compounds or acylphosphine oxide compounds are preferred as free radical photoinitiators. That is, component (D) is preferably an acylphosphine oxide photoinitiator and / or an alkyl phenyl ketone photoinitiator.

[0066] Examples of alkylphenyl ketone compounds include 1-hydroxycyclohexylphenyl ketone, and examples of acylphosphine oxide compounds include 2,4,6-trimethylbenzoyl-diphenylphosphine oxide or bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide. As component (D), one type can be used alone, or two or more types can be used in combination. Furthermore, from the viewpoint of balancing gloss and transparency, it is preferable to use both alkylphenyl ketone compounds and acylphosphine oxide compounds as component (D). When two or more types are used together, the content of component (D) refers to the total amount.

[0067] In one embodiment of the present invention, the content of component (D) in the photocurable resin composition is 0.1 to 15 parts by weight, more preferably 1 to 12 parts by weight, and even more preferably 3 to 9 parts by weight, relative to 100 parts by weight of the total content of components (A) and (B). By having the content of component (D) relative to the total content of components (A) and (B) within the above range, a photocurable resin composition with low heat of curing and excellent curability can be obtained.

[0068] <(E) Components>

[0069] One aspect of the photocurable resin composition of the present invention may contain water (H2O) as component (E). The water is preferably free of impurities, and particularly preferably pure water. By adding component (E), the curing heat of the photocurable resin composition can be further reduced.

[0070] The lower limit of the content of component (E) in the photocurable resin composition according to one aspect 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, relative to 100 parts by mass of the total content of components (A) and (B). Furthermore, 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, relative to 100 parts by mass of the total content of components (A) and (B). Additionally, the preferred addition amount here refers to the amount of water added, which also contains impurities of component (C).

[0071] <Any ingredient>

[0072] The photocurable resin composition of one aspect 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, without prejudice to the purpose of the present invention.

[0073] One aspect of the photocurable resin composition of the present invention preferably contains a polyfunctional thiol compound. By containing a polyfunctional thiol compound, cross-linking is promoted, oxygen hindrance to (meth)acryloyl groups is reduced, and it is not necessary to wipe away uncured material remaining on the surface of the cured product. As polyfunctional thiols, there are no particular restrictions as long as a compound contains two or more thiol groups per molecule. 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(mercaptoacetate), and ethylene glycol bis(3-mercaptopropionate). 1,4-Butanediol dimercaptoacetate, tetraethylene glycol bis(3-mercaptopropionate), trimethylolpropane tri(mercaptoacetate), trimethylolpropane tri(3-mercaptopropionate), trimethylolpropane tri(3-mercaptobutyrate), tris[(3-mercaptopropionyloxy)-ethyl]isocyanurate, pentaerythritol tetra(mercaptoacetate), pentaerythritol tetra(3-mercaptopropionate), dipentaerythritol hexa(3-mercaptopropionate), 1,4-bis(3-mercaptobutyryloxy)butane, pentaerythritol tetra(3-mercaptobutyrate), pentaerythritol tetra(3-mercaptobutyrate), 1,3,5-tris(3-mercaptobutyloxyethyl)-1,3,5-triazine-2,4,6(1 H,3H,5H)-trione, dimercapto-diethyl sulfide, 1,8-dimercapto-3,6-dithiooctane, 1,2-bis[(2-mercaptoethyl)thio]-3-mercaptopropane, tetra(7-mercapto-2,5-dithioheptyl)methane, trithiocyanate, 1,2-phenylenediane, thiols, 4,4'-thiobisphenylthiol, 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-dioxooctane, 1,5-dimercapto-3-dimethylthiomethane (1,5-Dimercapto-3-Th iapentane), tri(2-hydroxyethyl)tripolyisocyanate trimercaptopropionate, 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)-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-2,4,6-trithiol, etc. Preferably, as polyfunctional thiols, examples include compounds obtained by reacting the hydroxyl groups originally present in trimethylolpropane, pentaerythritol, and dipentaerythritol with compounds having thiol groups or groups that become thiol groups after reaction. Particularly preferred are examples such as trimethylolpropane tris(3-mercaptopropionate), tris[(3-mercaptopropionyloxy)-ethyl]-tripolyisocyanate, pentaerythritol tetra(3-mercaptopropionate), pentaerythritol tetra(3-mercaptobutyrate), dipentaerythritol hexa(3-mercaptopropionate), and dipentaerythritol hexa(3-mercaptobutyrate). Most preferred is trimethylolpropane tris(3-mercaptopropionate). By containing the above-mentioned components, the curing properties and storage stability of the photocurable resin composition of this embodiment are improved.

[0074] In one embodiment of the present invention, the content of the polyfunctional thiol compound in the photocurable resin composition is preferably 0.1 to 30 parts by mass relative to 100 parts by mass of the total content of components (A) and (B), more preferably 3 to 25 parts by mass, and even more preferably 5 to 20 parts by mass. By keeping the content of the polyfunctional thiol compound within the above range, a photocurable resin composition with low heat of curing and excellent curability can be obtained.

[0075] In one aspect of the photocurable resin composition of the present invention, fillers may be added to improve the elastic modulus, flowability, etc. of the cured product without prejudice to the purpose of the present invention. Specific examples of fillers include inorganic powders and organic powders.

[0076] Examples of inorganic powder fillers include glass, calcined silica, alumina, mica, ceramics, silicone rubber powder, calcium carbonate, aluminum nitride, carbon powder, kaolin, dried clay minerals, dried diatomaceous earth, etc., but are not limited to these. These can be used individually or in combination of two or more. In one embodiment of the present invention, the content of inorganic powder in the photocurable resin composition is preferably about 0.1 to 200 parts by weight relative to the content of component (A) of 100 parts by weight.

[0077] Fumed silica is formulated to adjust the viscosity of photocurable resin compositions or to improve the mechanical strength of cured products. Preferably, fumed silica with surface treatments such as dimethylsilane, trimethylsilane, alkylsilane, methacryloxysilane, organochlorosilane, polydimethylsiloxane, and hexamethyldisilazane is used. Commercially available fumed silica products 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, and R7200 (manufactured by AEROSIL Corporation of Japan). These can be used individually or in combination of two or more.

[0078] Examples of fillers for organic powders include, but are not limited to, polyethylene, polypropylene, polystyrene, nylon, polyester, polyvinyl alcohol, polyvinyl butyral, polycarbonate, and poly(meth)acrylate. These can be used individually or in combination of two or more. In one embodiment of the present invention, the content of organic powder in the photocurable resin composition is preferably 0.1 to 200 parts by mass relative to 100 parts by mass of component (A).

[0079] One aspect of the photocurable resin composition of the present invention may contain conductive fillers. Examples include, but are not limited to, plated particles coated with a thin metal film on gold, silver, platinum, nickel, palladium, and organic polymer particles. These can be used individually or in combination of two or more.

[0080] One aspect of the photocurable resin composition of the present invention may contain a silane coupling agent. Silane coupling agents include, but are not limited to, γ-chloropropyltrimethoxysilane, octenyltrimethoxysilane, glycidyloctyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidylpropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane, γ-acylureapropyltriethoxysilane, p-styrenetrimethoxysilane, etc. 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 of one aspect of the present invention is preferably 0.05 to 30 parts by weight, more preferably 0.2 to 10 parts by weight, relative to 100 parts by weight of component (A).

[0081] In this invention, artificial nails refer to a layer formed on the nails of humans or animals for decoration and / or protection. Additionally, artificial nails may also include, for example, resin substrates (artificial nails) of any shape for the purpose of decoration and / or protection of the nails. Furthermore, the shape of artificial nails is not particularly limited; they can be formed to cover the nail, or they can be formed to elongate the nail and be larger than the nail itself. They can also be formed for the purpose of bonding accessories (decorative elements) such as stone to the nail to enhance its appearance.

[0082] Another aspect of the present invention is a cured product (cured product of the photocurable resin composition) obtained by curing the above-mentioned photocurable resin composition. Here, specific examples of cured products include base coats, color coats, and top coats used in nail art.

[0083] Artificial nails generally consist of a series of layers: a base coat (a layer designed to provide adhesion and prevent color migration), a color layer (a decorative layer containing pigments), and a top coat (a layer designed to seal, impart shine, and enhance aesthetics). The formation method involves forming a base coat on the nail surface, which is then cured with a light-curing resin composition; a color layer, which is cured with the same light-curing resin composition, is then formed on top of this base coat; and finally, a top coat, which is cured with the same light-curing resin composition, is formed on top of this color layer. The light-curing resin composition of this invention has a low curing heat, making it suitable for use as a base coat applied to the nail surface. Furthermore, while a thicker resin layer is sometimes applied and cured as a top coat to improve appearance, the low curing heat of this light-curing resin composition minimizes pain caused by curing heat, even with increased curing volume. Therefore, it is also suitable for use as a surface coat.

[0084] The following shows a preferred example of the method for covering (decorating) nails or artificial nails according to the present invention, but the method of the present invention is not limited to this method.

[0085] Before applying the photocurable resin composition of the present invention, when directly applying it to the nail, to improve adhesion, it is preferable to sand the surface of the nail with a nail file (or similar tool) and then remove dust, oil, moisture, etc., with a nail-specific solvent with ethanol as the main component. When applying the photocurable resin composition of the present invention, a coating film with a thickness of 50 to 300 μm is formed in the pre-curing state using a pen or brush. Alternatively, it can be directly applied to the cured film of a base coat resin or a coloring resin. A primer can also be used before application. As the irradiation device for curing, a commercially available nail UV lamp or nail LED lamp is used. As the irradiation time, 15 to 120 seconds is preferred, and 20 to 70 seconds is more preferred considering the effect on the fingers. In addition, as the cumulative light intensity, 300 to 1500 mJ / cm² is preferred. 2 More preferably, it is 500~1000 mJ / cm 2 In addition, when curing the topcoat with a light-curing resin composition, a step of wiping the surface of the cured material with an organic solvent can be included to eliminate stickiness and make the gloss look aesthetically pleasing.

[0086] The photocurable resin composition of the present invention can be manufactured by existing known methods. For example, it can be manufactured by mixing components (A) to (D) and other components in specified amounts as needed, using a planetary mixer or similar mixing method, under light-shielding conditions, preferably at a temperature of 10 to 50°C, for 0.1 to 5 hours.

[0087] <Methods of covering (decorating) nails or artificial nails>

[0088] Another aspect of the present invention is a method for covering nails or artificial nails, in which the above-mentioned photocurable resin composition is applied to the nail or artificial nail to form a coating film, and then the coating film is cured by irradiation with active energy rays. Furthermore, in this specification, "applied to nails or artificial nails" includes applying it directly to the surface of a human nail (original nail) or an artificial nail (nail extension), or applying it to one or more other layers formed on the surface of a human nail or artificial nail.

[0089] Example

[0090] The following examples illustrate the invention in more detail, but the invention is not limited to these examples. Furthermore, in the following examples, unless otherwise specified, operations are performed at room temperature (25°C).

[0091] <Preparation of Photocurable Resin Compositions>

[0092] The components shown below were collected in the proportions (parts by weight) 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. Furthermore, the proportions of component (C) shown in Table 1 include component (E) (water), which is present as an impurity in commercially available products. For example, in the photocurable resin composition of Example 1, component c1 is contained in a proportion of 6.15% by weight, of which 9-11% is water as component (E).

[0093] "(A)Component"

[0094] a1: 3-functional alicyclic urethane acrylate oligomer (ARTRESIN (registered trademark) KY-11 (85% by weight of KY-11 when the total amount of KY-11 is 100% by weight), manufactured by Genjo Kogyo Co., Ltd., weight average molecular weight: 5000).

[0095] (B) Ingredients

[0096] b1: Tripropylene glycol diacrylate (ARTRESIN (registered trademark) KY-11 (15% by weight of KY-11 when the total amount of KY-11 is 100% by weight, of which 15% by weight is tripropylene glycol diacrylate), manufactured by Nekami Kogyo Co., Ltd.)

[0097] b2: Dihydroxymethyl-tricyclododecane diacrylate (Light acrylate (registered trademark) DCP-A, manufactured by Kyoei Chemical Co., Ltd.)

[0098] b3: 2-hydroxypropyl methacrylate (acrylate HP, manufactured by Mitsubishi Rayon Co., Ltd.)

[0099] (C) Ingredients

[0100] c1: Polyglycerol (Polyglycerol #750, manufactured by Sakamoto Pharmaceutical Co., Ltd., molecular weight: 758, containing 9-11% water and less than 5% glycerol)

[0101] c2: Polyglycerol (Polyglycerol #310, manufactured by Sakamoto Pharmaceutical Co., Ltd., molecular weight: 314, containing 4-6% water and 5-15% glycerol)

[0102] c3: Polyglycerol (Polyglycerol 20PW, manufactured by Daicel Corporation, molecular weight: 1602, contains 10.1% water, does not contain glycerol)

[0103] c4: Polyglycerol (Polyglycerol XPW, manufactured by Daicel Corporation, molecular weight: 3222, contains 9.9% water, does not contain glycerol)

[0104] c5: Polyoxyethylene polyglycerol ether (SC-E750, manufactured by Sakamoto Pharmaceutical Co., Ltd., weight average molecular weight: 750, contains 0.11% water, glycerol-free)

[0105] c6: Polyoxypropylene polyglycerol ether (SC-P750, manufactured by Sakamoto Pharmaceutical Co., Ltd., weight average molecular weight: 750, contains 0.05% water, glycerol-free)

[0106] Comparative example of component (C), i.e., component (C')

[0107] c'1: Diaglycerol (Diaglycerol 801, manufactured by Sakamoto Pharmaceutical Co., Ltd., molecular weight: 166, containing 0.1% water and 1.0% glycerol)

[0108] c'2: Polyglycerol backbone hexafunctional acrylate (SA-TE6, manufactured by Sakamoto Pharmaceutical Co., Ltd., weight average molecular weight: 1,000, excluding water and glycerol)

[0109] (D) Ingredients

[0110] d1: 1-Hydroxycyclohexylphenyl ketone (DOUBLECURE 184, manufactured by Doublebond Chemical Company)

[0111] d2: 2,4,6-Trimethylbenzoyl-diphenylphosphine oxide (DOUBLECURE TPO, manufactured by Doublebond Chemical)

[0112] (E) Ingredients

[0113] e1: Water (pure water, manufactured by Kyoei Pharmaceutical Co., Ltd.)

[0114] Polyfunctional thiols

[0115] Trimethylolpropane tris(3-mercaptopropionate) (TMMP-20P, manufactured by SC Organic Chemicals Co., Ltd.)

[0116] The test methods used in the examples and comparative examples in Table 1 are described below.

[0117] <Determination of Curing Heat Reduction Rate>

[0118] Differential scanning calorimetry (DSC) was performed under active energy line irradiation. 0.5 mg of the photocurable resin composition from Table 1 was weighed into an aluminum sample pan. The sample pan was positioned in the specified location within the measuring apparatus, and an empty sample pan for reference was also positioned accordingly. A quartz cell was placed between the sample pan and the high-pressure mercury lamp. The measurement was started at an ambient temperature of 25°C. After standing at 25°C for 1 minute, the high-pressure mercury lamp was irradiated with 3 mW for 3 minutes, and finally, the sample was placed at 25°C for 1 minute, for a total measurement of 5 minutes. The lower the maximum value of the DSC peak (μW) (differential scanning calorimetry: the change in heat flow accompanying the endothermic and dissipative effects of the sample), the less heat would be perceived in the sensory tests described below. The photocurable resin composition X of the present invention and a resin composition Y containing no (C) component in resin composition X were prepared separately. When the maximum DSC peak value of resin composition X was set as α (mW) and the maximum DSC peak value of resin composition Y was set as β (mW), 100 - (α / β × 100) was defined as the curing heat reduction rate (%). In the present invention, the curing heat reduction rate is preferably greater than 5%, more preferably greater than 7%, further preferably greater than 9%, and most preferably greater than 13%.

[0119] That is, for a photocurable resin composition according to one embodiment of the present invention, preferably the maximum DSC peak value α (mW) of the photocurable resin composition X of the present invention and the maximum DSC peak value β (mW) of the resin composition Y having the composition after removing component (C) from the composition of the photocurable resin composition X satisfy the following formula (4).

[0120] [Mathematical Expression 1]

[0121]

[0122] <Sensory Test>

[0123] After degreasing the surface of human fingernails, the light-curing resin composition from Table 1 was applied to each nail to achieve a thickness of 100 μm. Then, a nail LED lamp (REXIAEX, 30W, wavelength 395~405nm) was used to cure the nails (curing conditions: irradiation time 30 seconds, cumulative light intensity 750 mJ / cm²). 2 The evaluation was conducted using the fingernails of three individuals, and the "curing heat" was determined according to the following evaluation criteria during curing. To ensure that the fingernails of the human hand do not feel hot, a "○" is preferred.

[0124] Evaluation Criteria

[0125] ○: Two or more people do not feel heat in their nails

[0126] ×: The nails of two or more people feel very hot.

[0127] <Viscosity Measurement>

[0128] Take 0.5 mL of each of the photocurable resin compositions listed in Table 1 and spray it into a measuring cup. Under the following conditions, measure the viscosity using an EHD type viscometer (manufactured by Toki Sangyo Co., Ltd.). Record the result as “viscosity (Pa·s)”. When applying nail coating (decoration), from the viewpoint of ease of operation such as suppressing flow and applying the composition, the viscosity of the composition is preferably 0.5 to 150 Pa·s.

[0129] Evaluation Criteria

[0130] ○: 0.5~150 Pa·s

[0131] ×: less than 0.5 Pa·s or greater than 150 Pa·s

[0132] Measurement Conditions

[0133] Conical impeller: 3° × R14

[0134] Speed: 1 rpm

[0135] Measurement time: 3 minutes

[0136] Measurement temperature: 25℃ (temperature control is achieved using a constant temperature bath).

[0137] <Hardness Measurement>

[0138] Place a 1mm thick spacer on a 1.0×150×150mm blue glass plate and coat it with resin. Then, overlap it with a PET film, followed by another blue glass plate to hold the resin in place. Use a high-pressure mercury lamp (curing conditions: cumulative light intensity 30kJ / m²). 2 Two sheets of blue glass were irradiated twice, once on the surface and once on the back, to create a 1mm thick cured product (the UV light passing through the PET film and blue glass was adjusted to meet the above curing conditions). Three cured products were made in the same way and left to stand for 2 hours. Then, the blue glass and PET film were peeled off, and the three 1mm thick sheet-like cured products were overlapped with the PET film-coated side facing up. The hardness of the overlapping sheet-like cured products was measured on a smooth surface using a D-type hardness tester. The measurement was performed five times, and the average of the three measurements excluding the maximum and minimum values ​​was calculated. In everyday life, a hardness of 70 or higher is preferred to prevent damage and peeling of the cured product.

[0139] Evaluation Criteria

[0140] ○:D70 or above

[0141] ×: Less than D70

[0142] Measurement Conditions

[0143] Hardness tester pressing speed: 3.0 mm / sec

[0144] Numerical reading method: The maximum value within 1 second after the front end of the hardness tester's measuring section is in close contact with the object being measured.

[0145] [Table 1]

[0146]

[0147] As can be seen from the examples in Table 1, these are light-curing resin compositions in which no heat is felt during curing. The content of component (C) differs in Examples 1 and 2, and the content of component (C) differs between Examples 1 and Examples 3-7. These compositions exhibit a high rate of reduction in heat generation during curing and are light-curing resin compositions in which no heat is felt during sensory testing. Furthermore, because they possess a viscosity range useful for application on nails and the cured product is sufficiently hard, they are suitable for application on human nails.

[0148] According to the comparative examples in Table 1, Comparative Example 1, lacking component (C), exhibited a 0% reduction in curing heat generation, resulting in a perceived heat in the sensory test. Comparative Example 2's c'1 was diglyceride with a molecular weight below 200, but it showed an opposite effect on reducing curing heat generation. Comparative Examples 3 and 4's c'2 were compounds with a polyglycerol backbone and methacrylamide groups, but they did not contribute to reducing curing heat generation, resulting in a perceived heat in the sensory test.

[0149] Industrial applicability

[0150] The photocurable resin composition of the present invention has low heat of curing, and its viscosity range is useful for application to nails. In addition, the cured product is a photocurable resin composition that is hard enough, so it can be widely used in the nail industry.

[0151] This application is based on Japanese Patent Application No. 2021-12014, filed on January 28, 2021, the disclosure of which is incorporated herein by reference in its entirety.

Claims

1. A light-curing resin composition for nails or artificial nails, comprising the following components (A) to (D) and a polyfunctional thiol compound, wherein, The product comprises, relative to 100 parts by mass of component (A), 10 to 200 parts by mass of component (B); relative to 100 parts by mass of components (A) and (B), 0.1 to 50 parts by mass of component (C); and 0.1 to 15 parts by mass of component (D), wherein component (C) has a molecular weight of 200 or more. (A) Ingredients: Carbamate (meth)acrylate oligomers; (B) Ingredients: Selected from (meth)acrylate monomers, (meth)acrylamide monomers and (meth)acrylic acid monomers, and excluding (A) ingredient; (C) Ingredients: Polyglycerol without (meth)acryloyl groups and / or compounds with a polyglycerol ether backbone without (meth)acryloyl groups; (D) Component: Photoinitiator.

2. The light-curing resin composition for nails or artificial nails according to claim 1, wherein, The molecular weight of component (C) is above 200 and below 5000.

3. The light-curing resin composition for nails or artificial nails according to claim 1 or 2, wherein, The component (C) is polyglycerol without (meth)acryloyl groups and / or polyoxyethylene polyglycerol ether without (meth)acryloyl groups.

4. The light-curing resin composition for nails or artificial nails according to claim 1 or 2, wherein, It also contains water as component (E).

5. The light-curing resin composition for nails or artificial nails according to claim 1 or 2, wherein, The component (D) is an acylphosphine oxide photoinitiator and / or an alkyl phenyl ketone photoinitiator.

6. The light-curing resin composition for nails or artificial nails according to claim 1 or 2, wherein it satisfies the following conditions: A light-curable 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 respectively. The maximum DSC peak value α of resin composition X and the maximum DSC peak value β of resin composition Y satisfy 100-(α / β×100)>5%, wherein, The unit for the maximum DSC peak value α is mW, and the unit for the maximum DSC peak value β is mW.

7. A cured product obtained by curing a nail or artificial nail according to any one of claims 1 to 6 with a light-curing resin composition.

8. A method for covering a nail or artificial nail, comprising the following steps: applying a light-curing resin composition according to any one of claims 1 to 6 to the nail or artificial nail to form a coating film, and then irradiating the coating film with active energy rays to cure the coating film.

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