Resin composition, cured product, article, and method for producing cured product

Abstract

To provide a resin composition which has high sensitivity to UV-LED, and is suppressed in discoloration occurring when irradiated with the UV-LED.SOLUTION: A resin composition is provided, for use in formation of a cured product by an ultraviolet light-emitting diode which contains a (meth)acrylic monomer (α) having one or more (meth)acrylic groups in the molecule, a photopolymerization initiator (β) having absorbance at 380 nm of 0.3 or more, other photopolymerization initiator (γ) having absorbance at 380 nm of less than 0.3, and an agent (δ) which has an absorption maximum wavelength of 300 nm or more and 400 nm or less, and improves ultraviolet sensitivity, wherein a content of a polyfunctional(meth)acrylic monomer (α3) in 100 pts.mass of the (meth)acrylic monomer (α) is 50 pts.mass or more, and a content of the other photopolymerization initiator (γ) with respect to 1 pts.mass of the photopolymerization initiator (β) is 0.05 pts.mass or more and 0.5 pts.mass or less.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a resin composition, a cured product, an article, and a method for producing a cured product.

Background Art

[0002] Conventionally, for curing an ultraviolet-curable resin composition, it has been common to use a mercury lamp, a xenon lamp, a metal halide lamp, etc. In recent years, however, the use of an ultraviolet light-emitting diode (UV-LED) has begun to be considered.

[0003] A UV-LED has an advantage in that its light source life is long and it is energy-saving as compared with conventional light sources.

[0004] Patent Document 1 discloses an active energy ray-curable coating composition which is characterized as a resin composition cured by a UV-LED and contains a mercapto-modified (meth)acrylate, a fluorescent brightening agent, and, as a photopolymerization initiator, an acylphosphine oxide-based photopolymerization initiator and a thioxanthone-based photopolymerization initiator.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] The emission wavelength range of a UV-LED is limited to a narrow range. Therefore, the total amount of ultraviolet energy is small as compared with a lamp light source that emits ultraviolet rays having a wide wavelength range. The present inventors have found a problem that the curing sensitivity of a resin composition is insufficient in irradiation with such a UV-LED.

[0007] In addition, the present inventors have found the problem that the resin composition discolors upon irradiation with UV-LED.

[0008] The present invention has been made in view of such circumstances. One object of the present invention is to provide a resin composition that has high sensitivity to UV-LED and further suppresses discoloration during UV-LED irradiation.

Means for Solving the Problems

[0009] The present inventors have completed the invention provided below and solved the above problems.

[0010] According to the present invention, a (meth)acrylic monomer (α) having one or more (meth)acrylic groups in the molecule, a photoinitiator (β) having an absorbance of 0.3 or more at 380 nm in the ultraviolet-visible light absorption spectrum measured by diluting to 0.1% by mass in acetonitrile, another photoinitiator (γ) having an absorbance of less than 0.3 at 380 nm in the ultraviolet-visible light absorption spectrum measured by diluting to 0.1% by mass in acetonitrile, an agent (δ) having an absorption maximum wavelength in the range of 300 nm or more and 400 nm or less and having an action of improving ultraviolet sensitivity, a resin composition used for forming a cured product by an ultraviolet light-emitting diode, containing in 100 parts by mass of the above (meth)acrylic monomer (α), the content of a polyfunctional (meth)acrylic monomer (α3) having three or more (meth)acrylic groups in the molecule is 50 parts by mass or more, when the content of the above photoinitiator (β) is 1 part by mass, the content of the other photoinitiator (γ) is in the range of 0.05 part by mass or more and 0.5 part by mass or less, the resin composition is provided.

[0011] According to the present invention, a cured product of the above resin composition is provided.

[0012] According to the present invention, an article comprising the above-mentioned cured product is provided.

[0013] According to the present invention, A film formation step in which a film is formed from the above resin composition, The process involves irradiating the obtained film with ultraviolet light using an ultraviolet light-emitting diode, A method for manufacturing a cured product is provided, comprising the above. [Effects of the Invention]

[0014] The present invention provides a resin composition that has high sensitivity to UV-LEDs and further suppresses discoloration during UV-LED irradiation. [Modes for carrying out the invention]

[0015] The present invention will be described below based on embodiments.

[0016] In this embodiment, unless otherwise specified, "A~B" indicating a numerical range means A or greater and B or less.

[0017] In this embodiment, non-volatile components refer to components excluding volatile components such as solvents.

[0018] In the notation of groups (atomic groups) in this embodiment, notations that do not specify whether they are substituted or unsubstituted include both unsubstituted and substituted groups. For example, "alkyl group" includes not only unsubstituted alkyl groups but also substituted alkyl groups.

[0019] In this embodiment, the term "(meth)acrylic" represents a concept that encompasses both acrylic and methacrylic. The same applies to similar terms such as "(meth)acrylate."

[0020] [Resin composition] The resin composition according to this embodiment is (Meth)acrylic monomer (α) having one or more (meth)acrylic groups in the molecule, A photopolymerization initiator (β) whose ultraviolet-visible light absorption spectrum measured after dilution in acetonitrile at 0.1% by mass has an absorbance of 0.3 or higher at 380 nm, and Other photopolymerization initiators (γ) whose absorbance at 380 nm in the ultraviolet-visible light absorption spectrum measured after dilution in 0.1% by mass in acetonitrile is less than 0.3, An agent (δ) having an absorption maximum wavelength in the range of 300 nm to 400 nm and having the effect of improving ultraviolet sensitivity, A resin composition used for curing products with ultraviolet light-emitting diodes, comprising: Of the above (meth)acrylic monomer (α) in 100 parts by mass, the content of polyfunctional (meth)acrylic monomer (α3) having three or more (meth)acrylic groups in the molecule is 50 parts by mass or more. When the content of the above-mentioned photopolymerization initiator (β) is 1 part by mass, the content of the other photopolymerization initiator (γ) is in the range of 0.05 parts by mass or more and 0.5 parts by mass or less.

[0021] The resin composition according to this embodiment has high sensitivity to UV-LEDs, and furthermore, discoloration during UV-LED irradiation is suppressed. The mechanism by which such effects are produced is not clear, but the following mechanism is hypothesized. For the sake of clarity, it should be noted that the scope of the present invention is not limited by the following explanation.

[0022] In the resin composition according to this embodiment, by using a photopolymerization initiator (β), other photopolymerization initiators (γ) and agent (δ) in combination, energy is efficiently propagated between these agents, and it is presumed that curing occurs sensitively even when irradiated with a UV-LED with a narrow wavelength range (e.g., 360-385 nm). It is also presumed that using a certain amount or more of polyfunctional (meth)acrylic monomer (α3) with many bonds contributes to curing. Furthermore, it is presumed that maintaining a certain ratio of photopolymerization initiator (β) to other photopolymerization initiators (γ) contributes to suppressing discoloration during UV-LED irradiation. Based on the above mechanism, it is presumed that the resin composition according to this embodiment has high sensitivity to UV-LEDs and further suppresses discoloration during UV-LED irradiation.

[0023] The components contained in the resin composition according to this embodiment will be described in detail below.

[0024] <(meth)acrylmonomer(α)> The (meth)acrylic monomer (α) according to this embodiment has one or more (meth)acrylic groups in its molecule.

[0025] Examples of (meth)acrylic monomers (α) include monofunctional monomers (α1) having one (meth)acrylic group in the molecule, difunctional monomers (α2) having two (meth)acrylic groups in the molecule, and polyfunctional monomers (α3) having three or more (meth)acrylic groups in the molecule.

[0026] Examples of monofunctional monomers (α1) include methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isodecyl (meth)acrylate, n-lauryl (meth)acrylate, n-stearyl (meth)acrylate, phenyl (meth)acrylate, benzyl (meth)acrylate, isobornyl (meth)acrylate, dimethyl (meth)acrylamide, diethyl (meth)acrylamide, di-n-propyl (meth)acrylamide, dibutyl (meth)acrylamide, (meth)acryloylmorpholine, tetrahydrofurfuryl (meth)acrylate, diacetone acrylamide, and ethoxy-diethylene glycol acrylate.

[0027] Examples of difunctional monomers (α2) include triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, dimethylol-tricyclodecane di(meth)acrylate, bisphenol A type epoxy di(meth)acrylate, bisphenol A type PO adduct di(meth)acrylate, hydroxypivalate neopentyl glycol di(meth)acrylate, polytetramethylene glycol di(meth)acrylate, hydroxyethyl (meth)acrylate, benzyl (meth)acrylate, and phenoxyethyl (meth)acrylate.

[0028] Examples of polyfunctional monomers (α3) include trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, EO-modified trimethylolpropane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, EO-modified pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, glycerin propoxytri(meth)acrylate, caprolactone-modified trimethylolpropane tri(meth)acrylate, pentaerythritol ethoxytetra(meth)acrylate, and caprolactam-modified dipentaerythritol hexa(meth)acrylate.

[0029] In 100 parts by mass of (meth)acrylic monomer (α), the content of polyfunctional (meth)acrylic monomer (α3) is 50 parts by mass or more, preferably 70 parts by mass or more, more preferably 90 parts by mass or more, and it is even more preferable that the entire amount of (meth)acrylic monomer (α) is polyfunctional (meth)acrylic monomer (α3). This allows for improved sensitivity to UV-LEDs. Furthermore, this makes it possible to improve the durability of cured products made by curing resin compositions.

[0030] There is no upper limit to the content of polyfunctional (meth)acrylic monomer (α3) in 100 parts by mass of (meth)acrylic monomer (α), and the entire amount of (meth)acrylic monomer (α) may be polyfunctional (meth)acrylic monomer (α3), which is usually 95 parts by mass or less.

[0031] The content of (meth)acrylic monomer (α) in the nonvolatile components of the resin composition according to this embodiment is preferably 50% by mass or more, preferably 70% by mass or more, and more preferably 90% by mass or more.

[0032] The content of (meth)acrylic monomer (α) in the nonvolatile components of the resin composition according to this embodiment is usually 99 parts by mass or less, and preferably 95 parts by mass or less.

[0033] The resin composition according to this embodiment may contain only one (meth)acrylic monomer (α), or it may contain two or more.

[0034] <Photopolymerization initiator (β)> The photopolymerization initiator (β) according to this embodiment has an absorbance of 0.3 or higher at 380 nm in the ultraviolet-visible light absorption spectrum measured after dilution in acetonitrile at 0.1% by mass.

[0035] A photopolymerization initiator (β) is an agent that absorbs light such as ultraviolet light and generates radicals.

[0036] Examples of photopolymerization initiators (β) include the following: Here, "Abs 380 " is the absorbance at 380 nm of the ultraviolet-visible light absorption spectrum measured after dilution with 0.1% by mass in acetonitrile. Omnirad TPO (2,4,6-trimethylbenzoyldiphenylphosphine oxide, Abs 380 = 1.6), Omnirad TPO-L (ethyl phenyl(2,4,6-trimethylbenzoyl)phosphinate, Abs 380 = 0.7), Omnirad 369 (2-(dimethylamino)-1-(4-morpholinophenyl)-2-benzyl-1-butanone, Abs 380 greater than 2.0), Omnirad 819 (phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, Abs 380 = 1.9), Omnirad EMK (4,4'-bis(diethylamino)benzophenone, Abs 380 = 0.8), Omnirad 379 (2-dimethylamino-2-(4-methyl-benzyl)-1-(4-morpholin-4-yl-phenyl)-butan-1-one, Abs 380 = 1.2), (All of the above are manufactured by IGM Resins) Irgacure OXE01 (1-[4-(phenylthio)phenyl]octane-1,2-dione-2-(O-benzoyloxime), Abs 380 greater than 2.0), Irgacure OXE02 (ethanone, 1-[8-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, 1-(O-acet yloxime), Abs 380 = 0.6), Irgacure 784 (di-η5-cyclopentadienylbis[2,6-difluoro-3-(pyrrol-1-yl)phenyltitanium(4)], Abs 380 = 1.9) (All of the above are manufactured by BASF)

[0037] The photopolymerization initiator (β) preferably contains a compound having a benzoyl group. The hydrogen on the benzene ring of the benzoyl group may be substituted with any group.

[0038] Examples of photopolymerization initiators (β) containing a benzoyl group include the following: Omnirad TPO(2,4,6-trimethylbenzoyldiphenylphosphine oxide, Abs 380 =1.6), Omnirad TPO-L(phenyl(2,4,6-trimethylbenzoyl)phosphinate ethyl, Abs 380 =0.7), Omnirad 369(2-(dimethylamino)-1-(4-morpholinophenyl)-2-benzyl-1-butanone, Abs 380 (is greater than 2.0), Omnirad 819 (phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, Abs 380 =1.9), Omnirad EMK(4,4'-bis(diethylamino)benzophenone, Abs 380 =0.8), Omnirad 379(2-dimethylamino-2-(4-methylbenzyl)-1-(4-morpholin-4-ylphenyl)-butan-1-one, Abs 380 =1.2), (All of the above are manufactured by IGM Resins.) Irgacure OXE01(1-[4-(phenylthio)phenyl]octane-1,2-dione-2-(O-benzoyloxime), Abs 380 (is greater than 2.0), Irgacure OXE02 (Ethanone, 1-[8-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]-,1-(O-acetyloxime), Abs 380 =0.6), (All of the above are manufactured by BASF.)

[0039] The photopolymerization initiator (β) more preferably contains an acylphosphine compound or an α-alkylaminophenone compound, and even more preferably contains an acylphosphine compound.

[0040] Examples of photopolymerization initiators (β) containing acylphosphine compounds include the following: Omnirad TPO(2,4,6-trimethylbenzoyldiphenylphosphine oxide, Abs 380 =1.6), Omnirad 819 (phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, Abs 380 =1.9) Products containing acylphosphine oxide compounds such as, Omnirad TPO-L(phenyl(2,4,6-trimethylbenzoyl)phosphinate ethyl, Abs 380 =0.7) Products containing acylphosphine ester compounds such as (All of the above are manufactured by IGM Resins.)

[0041] Examples of photopolymerization initiators (β) containing α-alkylaminophenone compounds include the following: Omnirad 369(2-(dimethylamino)-1-(4-morpholinophenyl)-2-benzyl-1-butanone, Abs 380 (is greater than 2.0), Omnirad 379(2-dimethylamino-2-(4-methylbenzyl)-1-(4-morpholin-4-ylphenyl)-butan-1-one, Abs 380 =1.2), (All of the above are manufactured by IGM Resins.)

[0042] The content of the above photopolymerization initiator (β) per 100 parts by mass of the above (meth)acrylic monomer (α) is preferably 1.0 part by mass or more, more preferably 2.0 parts by mass or more, even more preferably 5.0 parts by mass or more, and even more preferably 10 parts by mass or more. This allows for improved sensitivity to UV-LEDs. Furthermore, this makes it possible to improve the durability of cured products made by curing resin compositions.

[0043] The content of the above photopolymerization initiator (β) per 100 parts by mass of the above (meth)acrylic monomer (α) is preferably 20 parts by mass or less, more preferably 17 parts by mass or less, and even more preferably 15 parts by mass or less. This makes it possible to suppress discoloration during UV-LED irradiation.

[0044] The content of the above photopolymerization initiator (β) per 100 parts by mass of the above (meth)acrylic monomer (α) is preferably in the range of 1.0 part by mass or more and 20 parts by mass or less, more preferably 2.0 parts by mass or more and 17 parts by mass or less, and even more preferably 5.0 parts by mass or more and 15 parts by mass or less. This makes it possible to improve sensitivity to UV-LEDs, durability of cured products made by curing the resin composition, and suppression of discoloration during UV-LED irradiation.

[0045] The resin composition according to this embodiment may contain only one type of photopolymerization initiator (β), or it may contain two or more types.

[0046] <Other photopolymerization initiators (γ)> The other photopolymerization initiator (γ) according to this embodiment has an absorbance of less than 0.3 at 380 nm in the ultraviolet-visible light absorption spectrum measured after dilution in acetonitrile at 0.1% by mass.

[0047] Other photopolymerization initiators (γ) are agents that absorb light such as ultraviolet light and generate radicals.

[0048] Other examples of photopolymerization initiators (γ) include the following: Omnirad 184 (1-hydroxycyclohexyl phenyl ketone, Abs 380 (less than 0.1) Omnirad 754 (a mixture of 2-(2-oxo-2-phenylacetoxy-ethoxy)-ethyl oxyphenylacetic acid and 2-(2-hydroxy-ethoxy)-ethyl oxyphenylacetic acid, Abs 380=0.10) Omnirad 1173 (2-hydroxy-2-methylpropiophenone, Abs 380 (less than 0.1) Omnirad 127(2,2'-dihydroxy-2,2'-dimethyl-1,1'-[methylenebis(4,1-phenylene)]bis(propan-1-one), Abs 380 (less than 0.1) Omnirad 2959(1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one, Abs 380 (less than 0.1) (All of the above are manufactured by IGM Resins.)

[0049] The other photopolymerization initiator (γ) preferably contains a compound having a benzoyl group. The hydrogen atoms on the benzene ring of the benzoyl group may be substituted with any other group.

[0050] Other photopolymerization initiators (γ) containing a benzoyl group include the following: Omnirad 184 (1-hydroxycyclohexyl phenyl ketone, Abs 380 (less than 0.1) Omnirad 754 (a mixture of 2-(2-oxo-2-phenylacetoxy-ethoxy)-ethyl oxyphenylacetic acid and 2-(2-hydroxy-ethoxy)-ethyl oxyphenylacetic acid, Abs 380 =0.10) Omnirad 1173 (2-hydroxy-2-methylpropiophenone, Abs 380 (less than 0.1) Omnirad 127(2,2'-dihydroxy-2,2'-dimethyl-1,1'-[methylenebis(4,1-phenylene)]bis(propan-1-one), Abs 380 (less than 0.1) Omnirad 2959(1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one, Abs 380(less than 0.1) (All of the above are manufactured by IGM Resins.)

[0051] The other photopolymerization initiator (γ) more preferably contains one or more selected from the group consisting of hydroxyalkylphenone compounds, α-oxyphenylacetic acid derivatives, and α-hydroxyacetophenone compounds.

[0052] Other photopolymerization initiators (γ) containing hydroxyalkylphenone compounds include the following: Omnirad 184 (1-hydroxycyclohexyl phenyl ketone, Abs 380 (Less than 0.1, manufactured by IGM Resins)

[0053] Other photopolymerization initiators (γ) containing α-oxyphenylacetic acid derivatives include the following: Omnirad 754 (a mixture of 2-(2-oxo-2-phenylacetoxy-ethoxy)-ethyl oxyphenylacetic acid and 2-(2-hydroxy-ethoxy)-ethyl oxyphenylacetic acid, Abs 380 =0.10)

[0054] Other photopolymerization initiators (γ) containing α-hydroxyacetophenone compounds include the following: Omnirad 1173 (2-hydroxy-2-methylpropiophenone, Abs 380 (less than 0.1) Omnirad 127(2,2'-dihydroxy-2,2'-dimethyl-1,1'-[methylenebis(4,1-phenylene)]bis(propan-1-one), Abs 380 (less than 0.1) Omnirad 2959(1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one, Abs 380 (less than 0.1) (All of the above are manufactured by IGM Resins.)

[0055] When the content of the above-mentioned photopolymerization initiator (β) is 1 part by mass, the content of the above-mentioned other photopolymerization initiator (γ) is 0.05 parts by mass or more, preferably 0.1 parts by mass or more, and more preferably 0.2 parts by mass or more. This allows for a relatively lower content of the photopolymerization initiator (β), thereby suppressing discoloration during UV-LED irradiation.

[0056] When the content of the above-mentioned photopolymerization initiator (β) is 1 part by mass, the content of the above-mentioned other photopolymerization initiator (γ) is 0.5 parts by mass or less, preferably 0.4 parts by mass or less, and more preferably 0.3 parts by mass or less. This allows for a relatively higher content of the photopolymerization initiator (β), thereby improving UV-LED sensitivity.

[0057] When the content of the above-mentioned photopolymerization initiator (β) is 1 part by mass, the content of the above-mentioned other photopolymerization initiator (γ) is in the range of 0.05 parts by mass or more and 0.5 parts by mass or less, preferably in the range of 0.1 parts by mass or more and 0.4 parts by mass or less, and more preferably in the range of 0.2 parts by mass or more and 0.3 parts by mass or less. This makes it possible to suppress discoloration during UV-LED irradiation and further improve UV-LED sensitivity.

[0058] The resin composition according to this embodiment may contain only one other photopolymerization initiator (γ), or it may contain two or more other photopolymerization initiators (γ).

[0059] <agent (δ)> Agent (δ) is a compound that, when added to the resin composition according to this embodiment, has the effect of improving ultraviolet sensitivity.

[0060] The mechanism by which agent (δ) improves UV sensitivity is presumed to be that energy is efficiently transferred from agent (δ) to the other photopolymerization initiators (γ) mentioned above, thereby improving UV sensitivity.

[0061] Agent (δ) has an absorption maximum wavelength in the range of 300 nm to 400 nm.

[0062] Examples of agent (δ) are listed below. The absorption maximum wavelengths listed below are catalog values ​​or values ​​read from the absorption curves listed in the catalog. If the absorption maximum wavelength for agent (δ) is not available in the catalog, the maximum absorption wavelength is measured by dissolving or dispersing agent (δ) in a solvent that can dissolve or disperse agent (δ) and does not substantially shift the maximum absorption wavelength. Omnirad DETX (2,4-diethylthioxanthene-9-one, manufactured by IGM Resins, absorption maximum wavelengths 261nm and 385nm) Omnirad ITX (2-isopropylthioxanthone, manufactured by IGM Resins, absorption maximum wavelengths 255nm and 384nm) Tinopal OB CO(2,5-bis(5-tert-butyl-2-benzoxazolyl)thiophene, manufactured by BASF, absorption maximum wavelength 375nm) Omnistab OB KCB (1,4-bis(2-benzoxazolyl)naphthalene, manufactured by Deltachem, absorption maximum wavelength 370nm) Omnistab OB 1 (4,4'-bis(2-benzoxazolyl)stilbene, manufactured by Deltachem, absorption maximum wavelength 374 nm) Omnipol TX (carboxymethoxymethoxybenzophenone, manufactured by IGM Resins, absorption maximum wavelengths 245nm, 280nm, 390nm)

[0063] Agent (δ) preferably contains a thioxanthone compound and / or a benzoxazoline compound, and more preferably contains a benzoxazoline compound.

[0064] Examples of agents containing thioxanthone compounds (δ) include the following: Omnirad DETX (2,4-diethylthioxanthene-9-one, manufactured by IGM Resins, absorption maximum wavelengths 261nm and 385nm) Omnirad ITX (2-isopropylthioxanthone, manufactured by IGM Resins, absorption maximum wavelengths 255nm and 384nm)

[0065] Examples of agents containing benzoxazoline compounds (δ) include the following: Tinopal OB CO (2,5-bis(5-tert-butyl-2-benzoxazolyl)thiophene, manufactured by BASF) Omnistab OB KCB (1,4-bis(2-benzoxazolyl)naphthalene, manufactured by Deltachem) Omnistab OB 1 (4,4'-bis(2-benzoxazolyl)stilbene, manufactured by Deltachem)

[0066] When the total amount of the above-mentioned photopolymerization initiator (β) and the above-mentioned other photopolymerization initiator (γ) is 1 part by mass, the content of the above-mentioned agent (δ) is preferably 0.005 parts by mass or more, more preferably 0.01 parts by mass or more, and even more preferably 0.02 parts by mass or more. This allows for improved UV-LED sensitivity.

[0067] When the total amount of the above-mentioned photopolymerization initiator (β) and the above-mentioned other photopolymerization initiator (γ) is 1 part by mass, the content of the above-mentioned agent (δ) is preferably 0.1 parts by mass or less, more preferably 0.08 parts by mass or less, and even more preferably 0.05 parts by mass or less. This makes it possible to suppress discoloration during UV-LED irradiation.

[0068] When the total amount of the above-mentioned photopolymerization initiator (β) and the above-mentioned other photopolymerization initiator (γ) is 1 part by mass, the content of the above-mentioned agent (δ) is preferably in the range of 0.005 parts by mass or more and 0.1 parts by mass or less, more preferably in the range of 0.01 parts by mass or more and 0.08 parts by mass or less, and even more preferably in the range of 0.02 parts by mass or more and 0.05 parts by mass or less. This improves UV-LED sensitivity and suppresses discoloration during UV-LED irradiation.

[0069] The resin composition according to this embodiment may contain only one agent (δ) or two or more agents.

[0070] <Any component other than (α)~(δ)> The resin composition according to this embodiment may contain any other components not listed above.

[0071] The resin composition according to this embodiment may contain a filler as an optional component. By including a filler, the viscosity of the resin composition can be adjusted to a level suitable for application.

[0072] The filler can be either inorganic or organic. Examples of inorganic fillers include silica, glass, mica, zeolite, diatomaceous earth, graphite, clay, talc, salts such as calcium carbonate, metals, and metal oxides. Examples of organic fillers include polyurethane particles, polyethylene particles, polystyrene particles, (meth)acrylic resin particles, polycarbonate particles, benzoguanamine / formaldehyde condensate particles, benzoguanamine / melamine / formaldehyde condensate particles, urea resin particles, and wax particles.

[0073] When the resin composition according to this embodiment contains a filler, the content of the filler in the nonvolatile components of the resin composition according to this embodiment is usually 1 to 50% by mass, preferably 2 to 45% by mass, and more preferably 3 to 40% by mass.

[0074] If the resin composition according to this embodiment contains a filler, the resin composition according to this embodiment may contain only one type of filler, or it may contain two or more types of fillers.

[0075] The resin composition according to this embodiment may contain a dispersant as an optional component. The dispersant is used to disperse insoluble components such as fillers in the resin composition.

[0076] Commercially available dispersants include BYK's "DISPERBYK" series and "BYK" series, TEGO's "DISPERS" series, and Lubrizol's "Solsperse" series.

[0077] When the resin composition according to this embodiment contains a dispersant, the content of the dispersant in the nonvolatile components of the resin composition according to this embodiment is usually 0.01 to 10% by mass, preferably 0.01 to 8% by mass.

[0078] If the resin composition according to this embodiment contains a dispersant, the resin composition according to this embodiment may contain only one type of dispersant or two or more types.

[0079] The resin composition according to this embodiment may contain a resin as an optional component. The resin is used for purposes such as forming a coating film and improving the adhesion of the coating film.

[0080] The resin is not particularly limited, and examples include (meth)acrylic resin, urethane (meth)acrylate resin, melamine resin, polyester resin, alkyd resin, silicone resin, fluororesin, epoxy resin, oxetane resin, vinyl chloride resin, polyurethane resin, etc. If the resin is a copolymer, its form may be random, block, graft, or any other.

[0081] When the resin composition according to this embodiment contains resin, the resin content in the nonvolatile components of the resin composition according to this embodiment is usually 1 to 50% by mass, preferably 2 to 45% by mass, and more preferably 3 to 40% by mass.

[0082] If the resin composition according to this embodiment contains a resin, the resin composition according to this embodiment may contain only one type of resin or two or more types of resin.

[0083] The resin composition according to this embodiment may also contain, in addition to the above-mentioned optional components, colorants, defoamers, leveling agents, polymerization inhibitors, waxes, antioxidants, non-reactive polymers, fine particle inorganic fillers, silane coupling agents, light stabilizers, UV absorbers, antistatic agents, slip agents, antibacterial agents, solvents (water and / or organic solvents), etc.

[0084] The resin composition according to this embodiment preferably does not contain thermosetting components. This prevents unintended changes in physical properties when heat is applied to the resin composition.

[0085] Examples of thermosetting components include compounds having a cyclic ether skeleton. Furthermore, epoxy compounds can be considered as compounds having a cyclic ether skeleton. Examples of epoxy compounds include phenol novolac type epoxy resins, bisphenol A type epoxy resins, bisphenol A-novolac type epoxy resins, bisphenol F type epoxy resins, bisphenol AD ​​type epoxy resins, biphenyl type epoxy resins, biphenyl novolac type epoxy resins, hydrogenated bisphenol A type epoxy resins, naphthalene type epoxy resins, hydroquinone type epoxy resins, tert-butylcatechol type epoxy resins, dicyclopentadiene type epoxy resins, adamantane type epoxy resins, biphenyl ether type epoxy resins, special bifunctional epoxy resins, and other bisphenol-based epoxy resins not listed above.

[0086] The viscosity (measured at 25°C) of the resin composition according to this embodiment is not particularly limited, but is usually 400 m·Pa or higher, preferably 1000 m·Pa or higher, and more preferably 1500 m·Pa or higher. Furthermore, there is no particular upper limit to the viscosity (measured at 25°C) of the resin composition according to this embodiment, but it is usually 10,000 m·Pa or less. Having a viscosity within a certain range in this way makes it possible to improve the applicability of the resin composition according to this embodiment.

[0087] [Cured product] The cured product according to this embodiment is a cured product of the above-described resin composition.

[0088] The cured product according to this embodiment is applied to the surface of articles such as wooden articles like flooring and furniture in houses, paper articles like books, and plastic articles like exterior materials for home appliances and electronic devices. In other words, the cured product can be applied to the surface of the article by applying the resin composition to the surface of the article and curing it.

[0089] Furthermore, a resin composition can be applied to any surface, cured, and then peeled off to obtain a cured film or sheet.

[0090] [Goods] The article according to this embodiment comprises the cured material described above.

[0091] Examples of articles according to this embodiment include wooden articles such as flooring and furniture for houses, paper articles such as books, and plastic articles such as exterior materials for home appliances and electronic devices.

[0092] The article according to this embodiment has excellent stain resistance due to the presence of the above-mentioned cured material. The stain resistance of the article can be evaluated, for example, by the JAS plywood staining A test.

[0093] [Method for manufacturing hardened products] The method for producing a cured product according to this embodiment is: A film formation step in which a film is formed from the above resin composition, The process involves irradiating the obtained film with ultraviolet light using an ultraviolet light-emitting diode, It is equipped with.

[0094] In the film formation process, the amount of resin composition applied is, for example, 2 to 220 g / m². 2 Preferably 4-110 g / m² 2 That is the case.

[0095] The resin composition can be applied by any method / apparatus. Preferably, the film formation process is carried out by roll coating, flow coating (also called curtain coating), or spraying. These methods are industrially suitable for forming a uniform film on the substrate and are therefore preferred for the film formation process.

[0096] In the irradiation process, the wavelength range of ultraviolet light irradiated from the ultraviolet light-emitting diode is, for example, 350 to 420 nm, preferably 360 to 385 nm.

[0097] The exposure dose during the irradiation process is, for example, 150-800 mJ / cm². 2 Preferably 300-600 mJ / cm² 2 Of course, the exposure amount can be adjusted appropriately depending on the sensitivity and film thickness of the resin composition used.

[0098] The intensity during the irradiation process is, for example, 10 to 5000 W / cm². 2 Preferably 50-2000 W / cm² 2 Of course, the strength can be adjusted as appropriate depending on the sensitivity, film thickness, etc., of the resin composition used.

[0099] The irradiation process may consist of multiple irradiation steps. In that case, it is sufficient that at least one of the multiple irradiation steps is performed using an ultraviolet light-emitting diode (UV-LED).

[0100] When multiple irradiation steps include irradiation means other than UV-LEDs, examples of ultraviolet irradiation means other than UV-LEDs include ultraviolet irradiation using mercury lamps, xenon lamps, or metal halide lamps.

[0101] The method for manufacturing a cured product according to this embodiment may further include a step of curing the resin composition by irradiating it with light other than ultraviolet light, such as infrared light or visible light.

[0102] Furthermore, the method for producing a cured product according to this embodiment may further include a step of curing the resin composition by heating.

[0103] Although embodiments of the present invention have been described above, these are merely examples, and various other configurations can be adopted. Furthermore, the present invention is not limited to the embodiments described above, and modifications, improvements, etc., within the scope of achieving the objectives of the present invention are included. [Examples]

[0104] Embodiments of the present invention will be described in detail based on examples and comparative examples. It should be noted that the present invention is not limited to these examples.

[0105] [Preparation of resin composition] Each component shown in Table 1 was prepared in the amounts (unit: parts by mass) shown in the table and thoroughly mixed to obtain a resin composition.

[0106] Details of each component shown in Table 1 are as follows.

[0107] <Monofunctional (meth)acrylic monomer (α1)> • ACMO (Acryloylmorpholine, manufactured by KJ Chemicals) • IBXA (isobornyl acrylate, manufactured by Osaka Organic Chemical Industry Co., Ltd.)

[0108] <Bifunctional (meth)acrylic monomer (α2)> • Miramer M284 (polyethylene glycol diacrylate, manufactured by Miwon Specialty Chemical) • EBECRYL 605 (Bisphenol A type epoxy diacrylate (75%), Tripropylene glycol diacrylate (25%), manufactured by Daicel Ornex Co., Ltd.)

[0109] <Polyfunctional (meth)acrylic monomer (α3)> • DPHA (Dipentaerythritol Hexaacrylate, manufactured by Daicel Ornex) • PETIA (a mixture of pentaerythritol triacrylate and pentaerythritol tetraacrylate, manufactured by Daicel Ornex) • TMP-3 (EO-modified trimethylolpropane triacrylate, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.)

[0110] <Photopolymerization initiator (β)> Here, "Abs 380 " is the absorbance at 380 nm of the ultraviolet-visible light absorption spectrum measured after dilution with 0.1% by mass in acetonitrile. • Omnirad TPO (Photopolymerization initiator containing acylphosphine compounds (β), 2,4,6-trimethylbenzoyldiphenylphosphine oxide, manufactured by IGM Resins, Abs 380 =1.6) • Omnirad TPO-L (a photopolymerization initiator containing an acylphosphine compound (β), ethyl phenyl(2,4,6-trimethylbenzoyl)phosphinate, manufactured by IGM Resins, Abs 380 =0.7) • Omnirad 369 (α-alkylaminophenone compound-containing photopolymerization initiator (β), 2-(dimethylamino)-1-(4-morpholinophenyl)-2-benzyl-1-butanone, manufactured by IGM Resins, Abs 380 (greater than 2.0)

[0111] <Other photopolymerization initiators (γ)> • Omnirad 184 (Other photopolymerization initiators containing hydroxyalkylphenone compounds (γ), 1-hydroxycyclohexylphenyl ketone, manufactured by IGM Resins, Abs 380 (less than 0.1) • Omnirad 754 (α-oxyphenylacetic acid derivative-containing other photopolymerization initiators (γ), a mixture of 2-(2-oxo-2-phenylacetoxy-ethoxy)-ethyl oxyphenylacetic acid and 2-(2-hydroxy-ethoxy)-ethyl oxyphenylacetic acid, manufactured by IGM Resins, Abs 380 =0.10) • Omnirad 1173 (α-hydroxyacetophenone compound-containing other photopolymerization initiators (γ), 2-hydroxy-2-methylpropiophenone, manufactured by IGM Resins, Abs 380 (less than 0.1)

[0112] <agent (δ)> • Omnirad DETX (a compound containing thioxanthone compounds (δ), 2,4-diethylthioxanthene-9-one, manufactured by IGM Resins, absorption maximum wavelengths 261 nm and 385 nm) Tinopal OB CO (a compound containing a benzoxazoline derivative (δ), 2,5-bis(5-tert-butyl-2-benzoxazolyl)thiophene, manufactured by BASF, absorption maximum wavelength 375 nm) • Omnistab OB KCB (An agent containing a benzoxazoline compound (δ), 1,4-bis(2-benzoxazolyl)naphthalene, manufactured by Deltachem, absorption maximum wavelength 370 nm)

[0113] <Filling material> • Silica 550 (manufactured by Fuji Silica Co., Ltd.)

[0114] <Dispersant> • DISPERBYK-2008 (polymer dispersant, manufactured by BYK)

[0115] [Viscosity measurement of resin compositions] For each resin composition, viscosity was measured using a Type B viscometer (model name TVB-10M) manufactured by Toki Sangyo Co., Ltd., under conditions of 25°C atmosphere, TM3 rotor, and rotation speed of 60 rpm. The results are shown in Table 1.

[0116] [Preparation of test coated panels] First, I prepared a piece of plywood measuring 60cm in length, 30cm in width, and 1.2cm in total thickness, with a 0.25mm thick oak veneer applied to the surface. This plywood was coated with a colored paint (Natco Flora No. 300: urethane dispersion type colored paint) at a rate of 33g / m². 2The plywood was then painted using a roll coater to achieve the desired finish. Afterwards, it was dried with 100°C hot air for 60 seconds to obtain the colored plywood.

[0117] The primer composition obtained by mixing the following components onto colored plywood is applied at a rate of 44 g / m². 2 It was painted to achieve this. This was then treated with ultraviolet light (irradiation dose 100 mJ / cm²). 2 , maximum irradiation intensity 80mW / cm 2 The painted primer composition was cured by irradiating it with ) and a primer layer was provided. (Components of the primer composition) • Urethane acrylate (product name: EBECRYL210, manufactured by Daicel Ornex Co., Ltd.) 40 parts by mass • Acryloylmorpholin (manufactured by KJ Chemical Co., Ltd.) 30 parts by mass • Radical polymerization initiator (product name: OMNIRAD1173, manufactured by IGM Resins) 6 parts by mass • Talc 24 parts by mass

[0118] Subsequently, the plywood with the undercoat layer was sanded with 320-grit waterproof sandpaper to obtain a substrate (a substrate to which the UV-LED curable resin composition would be applied).

[0119] The above resin composition was applied to the above substrate using a roll coater, with a coating rate of 16 g / m². 2 The coating was applied to a film thickness of 15 μm. Next, the surface coated with the resin composition was irradiated with a UV-LED and passed through a UV-LED irradiation device (UELCLP385-20028T, 385nm, 40cm irradiation port, manufactured by iGraphics Co., Ltd.). The speed at which light passes through is determined by the cumulative light intensity in the UV-V region (395-445 nm) measured with the UV Power Puck® II (manufactured by EIT Corporation) to 200 mJ / cm². 2 The intensity is 2000 mW / cm². 2 It was prepared to achieve this. The coated panels were obtained by repeatedly passing the coating over several passes until it was determined to be cured, according to the following criteria.

[0120] <Criteria for determining hardening> Steel wool #000 was placed on the UV-LED irradiated surface of the coated plate obtained as described above, at a density of 1 kg / cm². 2 The material was subjected to a load and subjected to 10 back-and-forth passes. When no visible scratches appeared, it was determined that the material had hardened.

[0121] [UV-LED sensuality] The UV-LED functionality of the resin composition was evaluated on a four-point scale based on the number of passes required for curing, according to the following criteria. A lower number of passes indicates superior UV-LED functionality. The results are shown in Table 1. ◎(Excellent): Number of passes: 2 or less ○ (Good): Number of passes: 3 △ (OK): Number of passes: 4 × (Not allowed): More than 5 passes

[0122] [Stain resistance] The stain resistance of the above-mentioned coated boards was evaluated in accordance with the JAS plywood staining test A. Specifically, a 10 mm wide line was drawn with blue ink on the surface of the coated plate irradiated with a UV-LED, left for 4 hours, and then wiped off with a cloth soaked in methanol. Next, the color difference (ΔE) with the untested area was measured in accordance with JIS Z 8781-4:2013 and evaluated on a four-point scale based on the following criteria. The results are shown in Table 1. ◎ (Excellent): ΔE is less than 0.5 ○ (Good): ΔE is between 0.5 and less than 1. △ (OK): ΔE is 1 or greater and less than 2 × (Not allowed): ΔE is 2 or greater

[0123] [Colorfastness] The color difference (ΔE) between the above substrate and the above coated plate was measured in accordance with JIS Z 8781-4:2013, and the discoloration of the resin composition was evaluated in four stages based on the following criteria. A smaller ΔE indicates that discoloration due to UV-LED irradiation is suppressed (excellent discoloration resistance). The results are shown in Table 1. ◎ (Excellent): ΔE is less than 3 ○ (Good): ΔE is 3 or greater and less than 4. △ (OK): ΔE is 4 or greater and less than 5 ×: (Not allowed) ΔE is 5 or greater

[0124] [Table 1]

[0125] Examples 1 to 15 exhibited excellent UV-LED functionality and suppressed discoloration. This indicates that the resin composition according to this embodiment has high sensitivity to UV-LEDs and further suppresses discoloration during UV-LED irradiation. On the other hand, Comparative Example 1, in which the content of polyfunctional (meth)acrylic monomer (α3) in 100 parts by mass of (meth)acrylic monomer (α) was less than 50 parts by mass, Comparative Example 2, which did not contain a photopolymerization initiator (β), Comparative Example 3, which did not contain other photopolymerization initiators (γ), and Comparative Example 4, which did not contain an agent (δ), were inferior in UV-LED functionality.

[0126] A more detailed analysis of the examples reveals the following: Examples 1-3 show that the higher the content of the photopolymerization initiator (β), the better the UV-LED functionality tends to be. Examples 2, 12, and 13 show that when the photopolymerization initiator (β) is acylphosphine-based, it tends to exhibit excellent discoloration resistance. Examples 10 and 11 show that the higher the content of agent (δ), the more likely it is that the UV-LED functionality will be superior.

Claims

1. (Meth)acrylic monomer (α) having one or more (meth)acrylic groups in the molecule, A photopolymerization initiator (β) whose ultraviolet-visible light absorption spectrum measured after dilution in acetonitrile at 0.1% by mass has an absorbance of 0.3 or higher at 380 nm, and Other photopolymerization initiators (γ) whose absorbance at 380 nm in the ultraviolet-visible light absorption spectrum measured after dilution in 0.1% by mass of acetonitrile is less than 0.3, An agent (δ) having an absorption maximum wavelength in the range of 300 nm to 400 nm and having the effect of improving ultraviolet sensitivity, A resin composition used for curing products with ultraviolet light-emitting diodes, comprising: In 100 parts by mass of the (meth)acrylic monomer (α), the content of polyfunctional (meth)acrylic monomer (α3) having three or more (meth)acrylic groups in the molecule is 50 parts by mass or more. When the content of the aforementioned photopolymerization initiator (β) is 1 part by mass, the content of the aforementioned other photopolymerization initiator (γ) is in the range of 0.05 parts by mass or more and 0.5 parts by mass or less. The polyfunctional (meth)acrylic monomer (α3) contains one or more selected from the group consisting of trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, EO-modified trimethylolpropane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, EO-modified pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, glycerin propoxytri(meth)acrylate, caprolactone-modified trimethylolpropane tri(meth)acrylate, pentaerythritol ethoxytetra(meth)acrylate, and caprolactam-modified dipentaerythritol hexa(meth)acrylate. The photopolymerization initiator (β) contains an acylphosphine compound and / or an α-alkylaminophenone compound, The aforementioned other photopolymerization initiator (γ) contains one or more selected from the group consisting of hydroxyalkylphenone compounds, α-oxyphenylacetic acid derivatives, and α-hydroxyacetophenone compounds. A resin composition comprising an agent (δ) having the effect of improving ultraviolet sensitivity, which contains a benzoxazoline compound.

2. The resin composition according to claim 1, A resin composition comprising the agent (δ) having the effect of improving ultraviolet sensitivity, which contains 2,5-bis(5-tert-butyl-2-benzoxazolyl)thiophene.

3. (Meth)acrylic monomer (α) having one or more (meth)acrylic groups in the molecule, A photopolymerization initiator (β) whose ultraviolet-visible light absorption spectrum measured after dilution in acetonitrile at 0.1% by mass has an absorbance of 0.3 or higher at 380 nm, and Other photopolymerization initiators (γ) whose absorbance at 380 nm in the ultraviolet-visible light absorption spectrum measured after dilution in 0.1% by mass of acetonitrile is less than 0.3, An agent (δ) having an absorption maximum wavelength in the range of 300 nm to 400 nm and having the effect of improving ultraviolet sensitivity, A resin composition used for curing products with ultraviolet light-emitting diodes, comprising: In 100 parts by mass of the (meth)acrylic monomer (α), the content of polyfunctional (meth)acrylic monomer (α3) having three or more (meth)acrylic groups in the molecule is 50 parts by mass or more. When the content of the aforementioned photopolymerization initiator (β) is 1 part by mass, the content of the aforementioned other photopolymerization initiator (γ) is in the range of 0.05 parts by mass or more and 0.5 parts by mass or less. The polyfunctional (meth)acrylic monomer (α3) contains one or more selected from the group consisting of trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, EO-modified trimethylolpropane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, EO-modified pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, glycerin propoxytri(meth)acrylate, caprolactone-modified trimethylolpropane tri(meth)acrylate, pentaerythritol ethoxytetra(meth)acrylate, and caprolactam-modified dipentaerythritol hexa(meth)acrylate. The aforementioned photopolymerization initiator (β) contains an acylphosphine compound, The aforementioned other photopolymerization initiator (γ) contains one or more selected from the group consisting of hydroxyalkylphenone compounds, α-oxyphenylacetic acid derivatives, and α-hydroxyacetophenone compounds. A resin composition comprising an agent (δ) having the effect of improving ultraviolet sensitivity, which contains a thioxanthone compound.

4. A resin composition according to any one of claims 1 to 3, A resin composition wherein the photopolymerization initiator (β) contains a compound having a benzoyl group.

5. The resin composition according to claim 4, A resin composition wherein the photopolymerization initiator (β) contains one or two selected from the group consisting of 2,4,6-trimethylbenzoyldiphenylphosphine oxide and ethyl phenyl(2,4,6-trimethylbenzoyl)phosphinate.

6. A resin composition according to any one of claims 1 to 5, A resin composition wherein the aforementioned other photopolymerization initiator (γ) contains a compound having a benzoyl group.

7. A resin composition according to any one of claims 1 to 6, A resin composition in which the content of the photopolymerization initiator (β) is in the range of 1.0 part by mass or more and 20 parts by mass or less, relative to 100 parts by mass of the (meth)acrylic monomer (α).

8. A resin composition according to any one of claims 1 to 7, A resin composition in which, when the total amount of the photopolymerization initiator (β) and the other photopolymerization initiator (γ) is 1 part by mass, the content of the agent (δ) is in the range of 0.005 parts by mass or more and 0.1 parts by mass or less.

9. A cured product of the resin composition according to any one of claims 1 to 8.

10. An article comprising the cured product described in claim 9.

11. A film-forming step of forming a film from the resin composition according to any one of claims 1 to 8, The process involves irradiating the obtained film with ultraviolet light using an ultraviolet light-emitting diode, A method for manufacturing a cured product, comprising the following:

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