Photocurable resin composition, cured product, electronic component, and flexible display

Abstract

[Problem] To provide a photocurable resin composition which can be coated by an inkjet method and which has excellent flexibility of a cured film. [Solution] A photocurable resin composition comprising: a polyfunctional (meth) acrylate compound (a) having an isocyanuric acid skeleton and a (meth) acryloyl group; a first monofunctional (meth) acrylate compound (b1) containing a nitrogen atom; a second monofunctional (meth) acrylate compound (b2) having at least one functional group selected from the group consisting of an ether bond, an epoxy group, and a hydroxyl group; and a photopolymerization initiator (c).

Description

Technical Field

[0001] The present invention relates to a photocurable resin composition, a cured product, an electronic component and a flexible display. Background Art

[0002] Compared with photolithography, the inkjet method for forming a cured film requires fewer steps and has higher production efficiency. Therefore, it is expected to be used in the electronics field for circuit protection, light shielding of specific parts, and spacer formation.

[0003] In addition, there are cases where a cured film formed from a curable composition is required to have flexibility. For example, Patent Document 1 proposes a curable composition comprising a difunctional urethane acrylate, a thiol compound, and a polymerization initiator. Furthermore, Patent Document 2 proposes a curable composition in which the total mass of a trifunctional (meth)acrylate monomer, a tetrafunctional (meth)acrylate monomer, and an octafunctional (meth)acrylate monomer is greater than a specified value.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1 International Publication No. 2009 / 011211

[0007] Patent Document 2 International Publication No. 2019 / 054412 Summary of the Invention

[0008] Problems to be solved by the present invention

[0009] When a cured coating film on a substrate is bent, it is stretched and elongated. Therefore, the curable composition described in Patent Document 1 has insufficient elongation at break, making it difficult to use in applications requiring bending of 180° or more. In addition, the curable composition described in Patent Document 2 does not quickly return to its original size when a certain tension is applied externally and then released, making it difficult to use in applications requiring repeated flexibility.

[0010] An object of one embodiment of the present invention is to provide a photocurable resin composition that can be applied by an inkjet method and has excellent bendability of a cured film.

[0011] Means of solving the problem

[0012] The present invention includes the following embodiments.

[0013] [1] A photocurable resin composition comprising:

[0014] A polyfunctional (meth)acrylate compound (a) having an isocyanuric acid skeleton and a (meth)acryloyl group;

[0015] a first monofunctional (meth)acrylate compound (b1) containing a nitrogen atom;

[0016] a second monofunctional (meth)acrylate compound (b2) having at least one functional group selected from the group consisting of an ether bond, an epoxy group, and a hydroxyl group; and

[0017] Photopolymerization initiator (c).

[0018] [2] The photocurable resin composition described in [1], wherein the first monofunctional (meth)acrylate compound (b1) has at least one functional group selected from the group consisting of an amide bond, an imide bond, and a urethane bond.

[0019] [3] The photocurable resin composition according to [1] or [2], wherein the viscosity of the second monofunctional (meth)acrylate compound (b2) at 25° C. is 100 mPa·s or less.

[0020] [4] The photocurable resin composition described in any one of [1] to [3], wherein the second monofunctional (meth)acrylate compound (b2) comprises at least one selected from the group consisting of allyloxymethyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, cyclic trimethylolpropane formal (meth)acrylate, (2-methyl-2-ethyl-1,3-dioxolan-4-yl)methyl (meth)acrylate, 2-(2-vinyloxyethoxy)ethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate glycidyl ether, and 1,4-cyclohexanedimethanol mono(meth)acrylate.

[0021] [5] The photocurable resin composition described in any one of [1] to [4], wherein the content of the polyfunctional (meth)acrylate compound (a) is 10 parts by mass or more and 50 parts by mass or less in 100 parts by mass of the total of the polyfunctional (meth)acrylate compound (a), the first monofunctional (meth)acrylate compound (b1), and the second monofunctional (meth)acrylate compound (b2).

[0022] [6] The photocurable resin composition described in any one of [1] to [5], wherein the total content of the first monofunctional (meth)acrylate compound (b1) and the second monofunctional (meth)acrylate compound (b2) is 40 parts by mass or more and 80 parts by mass or less in 100 parts by mass of the total of the polyfunctional (meth)acrylate compound (a), the first monofunctional (meth)acrylate compound (b1) and the second monofunctional (meth)acrylate compound (b2).

[0023] [7] The photocurable resin composition according to any one of [1] to [6], wherein the viscosity at 25°C is 150 mPa·s or less.

[0024] [8] A cured product obtained by curing the photocurable resin composition according to any one of [1] to [7].

[0025] [9] An electronic component having a bent portion, wherein the bent portion comprises the cured product described in [8].

[0026]

[10] A flexible display comprising the cured product described in [8].

[0027] Effects of the Invention

[0028] According to one embodiment of the present invention, there can be provided a photocurable resin composition that can be applied by an inkjet method and has excellent bendability of a cured film. DETAILED DESCRIPTION

[0029] In this specification, the term "process" includes not only independent processes, but also, when it cannot be clearly distinguished from other processes, it is included in this term as long as the intended purpose of the process is achieved. In addition, when there are multiple substances corresponding to each component in the composition, unless otherwise specified, the content of each component in the composition refers to the total amount of the multiple substances present in the composition. In addition, the upper and lower limits of the numerical ranges described in this specification can be optionally combined with the numerical values ​​exemplified as numerical ranges. In this specification, "(meth)acrylate" is a term that collectively refers to acrylates, methacrylates and mixtures thereof, and the same applies to other similar expressions (for example, (meth)acryloyl). In addition, solid content refers to the remaining components after removing volatile components (for example, organic solvents) from the composition or its components. Below, embodiments of the present invention are described in detail. However, the embodiments shown below illustrate photocurable resin compositions, cured products, electronic components and flexible displays for concretizing the technical ideas of the present invention, and the present invention is not limited to the photocurable resin compositions, cured products, electronic components and flexible displays shown below.

[0030] Photocurable resin composition

[0031] The photocurable resin composition includes: a multifunctional (meth)acrylate compound (a; hereinafter referred to as the "multifunctional (meth)acrylate compound") having an isocyanuric acid skeleton and a (meth)acryloyl group; a first monofunctional (meth)acrylate compound (b1; hereinafter referred to as the "first monofunctional (meth)acrylate compound") containing a nitrogen atom; a second monofunctional (meth)acrylate compound (b2; hereinafter referred to as the "second monofunctional (meth)acrylate compound") having at least one functional group selected from the group consisting of an ether bond, an epoxy group and a hydroxyl group; and a photopolymerization initiator (c).

[0032] In addition to the polyfunctional (meth) acrylate compound with an isocyanuric acid skeleton, the curing film obtained by curing the photocurable resin composition containing a specific monofunctional (meth) acrylate compound is excellent in bendability and has high recoverability. It is also possible to take into account both high elastic modulus (rigidity) and excellent flexibility. For example, it can be considered as follows. It is considered that the cross-linked structure formed by the polyfunctional (meth) acrylate compound with an isocyanuric acid skeleton is densely formed by the intermolecular force acting on the isocyanuric acid skeleton, and the elastic modulus (rigidity) can be improved by increasing the cross-linking density of acrylates. It is considered that by using a first monofunctional (meth) acrylate compound containing a nitrogen atom and a second monofunctional (meth) acrylate compound with an oxygen functional group, when a three-dimensional structure is formed by cross-linking, the reaction of the first and second monofunctional (meth) acrylate compounds with the polyfunctional (meth) acrylate with an isocyanuric acid skeleton is more likely to occur than the reaction between the polyfunctional (meth) acrylate with an isocyanuric acid skeleton. Therefore, it is considered that there is no local region with a high elastic modulus (rigidity) in the cured film formed, and flexibility is excellent. Because the first and second monofunctional (meth) acrylate compounds are monofunctional (meth) acrylates, it is considered that a coating film can be formed without excessively increasing the crosslinking density, and a cured film that takes into account both elastic modulus (rigidity) and flexibility can be formed at a high level. In addition, it is considered that a multifunctional (meth) acrylate compound can form a cured film with an extremely high elastic modulus (rigidity) by having an isocyanuric acid skeleton. Further, it is considered that the second monofunctional (meth) acrylate compound has a functional group comprising an oxygen atom, so that, for example, the adhesion to a polyethylene terephthalate (PET) substrate can be further improved. In addition, it is considered that the first monofunctional (meth) acrylate compound can easily undergo repetition with a multifunctional (meth) acrylate compound and acrylate having an isocyanuric acid skeleton by having a functional group comprising a nitrogen atom, and the flexibility of the cured film can be improved.

[0033] (a) Multifunctional (meth)acrylate compounds

[0034] The multifunctional (meth)acrylate compound has a skeleton derived from isocyanuric acid and two or three (meth)acryloyl groups. The skeleton derived from isocyanuric acid may also be an ethylene oxide (EO) modified form of isocyanuric acid. The multifunctional (meth)acrylate compound may be a di(meth)acrylate or a tri(meth)acrylate, or a mixture thereof. When the multifunctional (meth)acrylate compound is a mixture of a di(meth)acrylate and a tri(meth)acrylate, the content of the di(meth)acrylate may be, for example, 10% by mass or more and 90% by mass or less, preferably 20% by mass or more or 25% by mass or more, and further preferably 60% by mass or less or 50% by mass or less.

[0035] The polyfunctional (meth)acrylate compound can be appropriately selected from compounds available commercially, and specific examples thereof include: M-313 (THEIC type polyfunctional acrylate; manufactured by Toagosei Co., Ltd.), M-315 (THEIC type polyfunctional acrylate; manufactured by Toagosei Co., Ltd.), A-9300 (THEIC type polyfunctional acrylate; manufactured by Shin-Nakamura Chemical Co., Ltd.), and A-9200YN (THEIC type polyfunctional acrylate; manufactured by Shin-Nakamura Chemical Co., Ltd.).

[0036] The content of the multifunctional (meth)acrylate compound in 100 parts by mass of the total of the multifunctional (meth)acrylate compound, the first monofunctional (meth)acrylate compound, and the second monofunctional (meth)acrylate compound can be, for example, 3 parts by mass or more and 60 parts by mass or less, preferably 5 parts by mass or more, 8 parts by mass or more, 10 parts by mass or more, 20 parts by mass or more, or 25 parts by mass or more, and can be 55 parts by mass or less, 50 parts by mass or less, 40 parts by mass or less, 35 parts by mass or less, or 30 parts by mass or less. In one embodiment, the content of the multifunctional (meth)acrylate compound can be 10 parts by mass or more and 50 parts by mass or less. If the content of the multifunctional (meth)acrylate compound is within the above range, there is a tendency to achieve both high elastic modulus and high recovery.

[0037] (b1) First monofunctional (meth)acrylate compound

[0038] The first monofunctional (meth)acrylate compound has a functional group containing a nitrogen atom and a (meth)acryloyl group. As the functional group containing a nitrogen atom, there can be listed: a functional group containing a bonding structure of a nitrogen atom and a carbonyl group. The functional group containing a nitrogen atom can be a divalent functional group, for example, there can be listed: an amide bond, an imide bond, a carbamate bond, a urea bond, etc. The functional group containing a nitrogen atom can be at least one selected from the group consisting of an amide bond, an imide bond, a carbamate bond and a urea bond, and is preferably at least one selected from the group consisting of an amide bond, an imide bond and a carbamate bond. The functional group containing a nitrogen atom is more preferably at least one selected from the group consisting of an imide bond and a carbamate bond, and can also be modified with ethylene oxide (EO).

[0039] Specific examples of the first monofunctional (meth)acrylate compound include amide acrylate, imide acrylate, and urethane acrylate. The first monofunctional (meth)acrylate compound can be appropriately selected from commercially available compounds. Specific examples thereof include DMAA (N,N-dimethylacrylamide; manufactured by Cosmos Chemical Co., Ltd.), ACMO (acryloylmorpholine; manufactured by Cosmos Chemical Co., Ltd.), HEAA (N-(2-hydroxyethyl)acrylamide; manufactured by Cosmos Chemical Co., Ltd.), DAAM (diacetoneacrylamide; manufactured by Cosmos Chemical Co., Ltd.), NIPAM (N-isopropylacrylamide), DEAA (N,N-diethylacrylamide), DMAPA (N-[3-(dimethylamino)propyl]acrylamide), M-140 (imide acrylate; manufactured by Toagosei Co., Ltd.), KRM9276 (urethane acrylate; manufactured by Daicel Zenshin Co., Ltd.), and LD-301 (urethane acrylate; manufactured by Aegis Corporation).

[0040] The content of the first monofunctional (meth)acrylate compound in 100 parts by mass of the total of the multifunctional (meth)acrylate compound, the first monofunctional (meth)acrylate compound, and the second monofunctional (meth)acrylate compound can be, for example, 5 parts by mass or more and 80 parts by mass or less, preferably 10 parts by mass or more, 15 parts by mass or more, 20 parts by mass or more, or 25 parts by mass or more, and can be 75 parts by mass or less, 70 parts by mass or less, 65 parts by mass or less, 60 parts by mass or less, 55 parts by mass or less, 45 parts by mass or less, or 35 parts by mass or less. When the content of the first monofunctional (meth)acrylate compound is within the above range, a high elongation at break can be achieved, and the flexibility tends to be excellent.

[0041] The ratio of the content of the first monofunctional (meth)acrylate compound to the content of the multifunctional (meth)acrylate compound in the photocurable resin composition can be, for example, 0.2 or more and 20 or less, preferably 0.4 or more, 0.8 or more, or 2 or more, and preferably 17.5 or less, 15 or less, 12.5 or less, 8 or less, 4 or less, or 2 or less, based on mass.

[0042] (b2) Second monofunctional (meth)acrylate compound

[0043] The second monofunctional (meth)acrylate compound has a functional group containing an oxygen atom and one (meth)acryloyl group. Examples of the functional group containing an oxygen atom include an ether bond, an epoxy group, and a hydroxyl group, and may be at least one selected from the group consisting of these.

[0044] The viscosity of the second monofunctional (meth)acrylate compound at 25°C can be, for example, 200 mPa·s or less, preferably 100 mPa·s or less, 95 mPa·s or less, 90 mPa·s or less, 10 mPa·s or less, or 5 mPa·s or less. The viscosity of the second monofunctional (meth)acrylate compound at 25°C can be, for example, 1 mPa·s or greater. When the viscosity of the second monofunctional (meth)acrylate compound is within the above range, good inkjet printability is likely to be achieved.

[0045] Here, the viscosity of the second monofunctional (meth)acrylate compound is measured at 25°C, 50 rpm, and 30 seconds using a cone-plate viscometer (TVe-33H, manufactured by Toki Sangyo Co., Ltd.) using a 1°34'×R24 cone rotor in accordance with "Viscosity measurement method using a cone-plate type rotational viscometer" in JIS Z8803:2011 (10).

[0046] Specific examples of the second monofunctional (meth)acrylate compound include allyloxymethyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, cyclic trimethylolpropane formal (meth)acrylate, (2-methyl-2-ethyl-1,3-dioxolan-4-yl)methyl (meth)acrylate, 2-(2-vinyloxyethoxy)ethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate glycidyl ether, 1,4-cyclohexanedimethanol mono(meth)acrylate, 2-hydroxy-3-phenoxypropyl acrylate, phenoxyethyl acrylate, phenoxydiglycol acrylate, nonylphenoxydiglycol acrylate, 2-ethylhexyl diglycol acrylate, hydroxyethyl acrylate, hydroxypropyl acrylate, 4-hydroxybutyl acrylate, ethyl carbitol acrylate, and cyclic trimethylolpropane formal acrylate. The compound may also contain at least one selected from the group consisting of these.

[0047] The second monofunctional (meth)acrylate compound can be appropriately selected from commercially available compounds. Specific examples thereof include AOMA, VEEA (manufactured by Nippon Shokubai Co., Ltd.), VEEM, VISCOAT#155, VISCOAT#190, VISCOAT#192, VISCOAT#200, MEDOL-10 (manufactured by Osaka Organic Chemical Industry Co., Ltd.), SR256, SR285, and SR339N. S, SR495NS, SR504NS, SR531, SR551, SR611, CD9075, SR9087, SR203, SR340, CD545, SR550, CD730 (manufactured by Arkema), EBECRYL110, EBECRYL114 (manufactured by Daicel Chamsin Co., Ltd.), M-101A, M-102, M-111, M-113, M-120 (manufactured by Toagosei Co., Ltd.), etc.

[0048] The content of the second monofunctional (meth)acrylate compound in 100 parts by mass of the total of the multifunctional (meth)acrylate compound, the first monofunctional (meth)acrylate compound, and the second monofunctional (meth)acrylate compound can be, for example, 10 parts by mass or more and 85 parts by mass or less, preferably 12.5 parts by mass or more, 15 parts by mass or more, 17.5 parts by mass or more, 20 parts by mass or more, 25 parts by mass or more, 30 parts by mass or more, or 35 parts by mass or more, and can be 80 parts by mass or less, 75 parts by mass or less, 70 parts by mass or less, 60 parts by mass or less, 50 parts by mass or less, or 45 parts by mass or less. When the content of the second monofunctional (meth)acrylate compound is within the above range, there is a tendency to achieve both good adhesion to the substrate and excellent flexibility.

[0049] The total content of the first monofunctional (meth)acrylate compound and the second monofunctional (meth)acrylate compound in 100 parts by mass of the total of the multifunctional (meth)acrylate compound, the first monofunctional (meth)acrylate compound, and the second monofunctional (meth)acrylate compound can be, for example, 30 parts by mass or more and 95 parts by mass or less, preferably 32.5 parts by mass or more, 35 parts by mass or more, 37.5 parts by mass or more, 40 parts by mass or more, 50 parts by mass or more, 55 parts by mass or more, 60 parts by mass or more, or 65 parts by mass or more, and can be 92.5 parts by mass or less, 90 parts by mass or less, 85 parts by mass or less, 80 parts by mass or less, or 75 parts by mass or less. In one embodiment, the total content of the first monofunctional (meth)acrylate and the second monofunctional (meth)acrylate compound can be 40 parts by mass or more and 80 parts by mass or less. If the total content of the first monofunctional (meth)acrylate and the second monofunctional (meth)acrylate compound is within the above range, there is a tendency to achieve both a high elastic modulus and excellent flexibility.

[0050] The ratio of the content of the second monofunctional (meth)acrylate compound to the content of the multifunctional (meth)acrylate compound in the photocurable resin composition can be, for example, 0.2 or more and 20 or less, preferably 0.4 or more, 0.8 or more, or 1 or more, and preferably 17.5 or less, 15 or less, 12.5 or less, 10 or less, 6 or less, 4 or less, or 2 or less, based on mass.

[0051] The ratio of the total content of the first monofunctional (meth)acrylate compound and the second monofunctional (meth)acrylate compound to the content of the multifunctional (meth)acrylate compound in the photocurable resin composition can be, for example, 0.25 or more and 50 or less, preferably 0.5 or more, 0.8 or more, 1.2 or more, 1.8 or more, or 2 or more, and preferably 40 or less, 30 or less, 20 or less, 12 or less, 8 or less, or 4 or less, on a mass basis.

[0052] The ratio of the content of the second monofunctional (meth)acrylate compound to the content of the first monofunctional (meth)acrylate compound in the photocurable resin composition can be, for example, 0.1 or more and 5 or less, preferably 0.25 or more, 0.6 or more, or 1 or more, and preferably 4.5 or less, 4 or less, 3.5 or less, 2 or less, 1.6 or less, or 1.4 or less, on a mass basis.

[0053] In addition to the multifunctional (meth) acrylate compound, the first monofunctional (meth) acrylate compound and the second monofunctional (meth) acrylate compound, the photocurable resin composition may also include other compounds with ethylenically unsaturated bonds as needed. As other compounds with ethylenically unsaturated bonds, vinyl compounds, allyl compounds, substituted allyl compounds, etc. can be listed. The photocurable resin composition may contain one other compound with ethylenically unsaturated bonds alone, or it may contain two or more in combination. As commercially available products of other compounds with ethylenically unsaturated bonds, NPVE, IPVE, NBVE, IBVE, EHVE, CHVE, HEVE, HBVE, CHMVE, BDVE, DEGDVE, CHDVE, TEGDVE (the above are manufactured by Nippon Carbide Industries, Ltd.), DEGV (manufactured by Maruzen Petrochemical Co., Ltd.), N-vinyl pyrrolidone, N-vinyl-2-caprolactam (the above are manufactured by Mitsui Pharmaceuticals Food Chemicals Co., Ltd.), etc.

[0054] When the photocurable resin composition further contains a compound having another ethylenically unsaturated bond, the content of the compound having another ethylenically unsaturated bond, based on the total content of the polyfunctional (meth)acrylate compound, the first monofunctional (meth)acrylate compound, and the second monofunctional (meth)acrylate compound being 100 parts by mass, can be, for example, 1.0 part by mass or more and 30 parts by mass or less, preferably 20 parts by mass or less, more preferably 10 parts by mass or less, or 2 parts by mass or less, in terms of solid content.

[0055] (c) Photopolymerization initiator

[0056] The photocurable resin composition contains at least one photopolymerization initiator. Examples of the photopolymerization initiator in the photocurable resin composition include benzophenone derivatives, thioxanthone derivatives, oxime ester compounds, benzoin derivatives, acetophenone derivatives, α-aminoacetophenone derivatives, hydroxyacetophenone derivatives, anthraquinone derivatives, and acylphosphine oxide compounds. The photopolymerization initiator may include at least one selected from the group consisting of these compounds, preferably at least one selected from the group consisting of acylphosphine oxide compounds and oxime ester compounds. The photocurable resin composition may contain a single photopolymerization initiator or a combination of two or more.

[0057] Examples of benzophenone derivatives include benzophenone, 4-phenylbenzophenone, 4,4'-diethylaminobenzophenone, methyl-o-benzoylbenzoate, 4-(4-methylphenylthio)benzophenone, 1-[4-(4-benzoylphenylsulfonyl)phenyl]-2-methyl-2-(4-methylphenyl)sulfonyl)propan-1-one, 4,4'-dichlorobenzophenone, hydroxybenzophenone, 4-benzoyl-4'-methyldiphenyl sulfide, 3,3',4,4'-tetrakis(tert-butylperoxycarbonyl)benzophenone, and 3,3'-dimethyl-4-methoxybenzophenone.

[0058] Examples of the thioxanthone derivative include 2-isopropylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, 2,4-diisopropylthioxanthone, and 4-isopropylthioxanthone.

[0059] Examples of the oxime ester compounds include 2-(O-benzoyloxy)-1-[4-(phenylthio)phenyl]-1,2-butanedione, 2-(O-benzoyloxy)-1-[4-(phenylthio)phenyl]-1,2-pentanedione, 2-(O-benzoyloxy)-1-[4-(phenylthio)phenyl]-1,2-hexanedione, 2-(O-benzoyloxime)-1-[4-(phenylthio)phenyl]-1,2-heptanedione, and 2-(O-benzoyloxime)-1-[4-(phenylthio)phenyl]-1,2-heptanedione. -(O-benzoyloxy)-1-[4-(phenylthio)phenyl]-1,2-octanedione, 2-(O-benzoyloxy)-1-[4-(methylphenylthio)phenyl]-1,2-butanedione, 2-(O-benzoyloxy)-1-[4-(ethylphenylthio)phenyl]-1,2-butanedione, 2-(O-benzoyloxy)-1-[4-(butylphenylthio)phenyl]-1,2-butanedione, 1-(O-acetoxy)-1-[4-(methylphenylthio)phenyl]-1,2-butanedione )-1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]ethanone, 1-(O-acetoxy)-1-[9-methyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]ethanone, 1-(O-acetoxy)-9-propoxy(2-methylbenzoyl)-9H-carbazol-3-yl]ethanone, 1-(O-acetoxy)-1-[9-ethyl-6-(2-ethylbenzoyl) -9H-carbazol-3-yl]ethanone, 1-(O-acetyloximo)-1-[9-ethyl-6-(2-butylbenzoyl)-9H-carbazol-3-yl]ethanone, 2-(benzoyloxyimino)-1-[4-(phenylthio)phenyl]-1-octanone, 2-(acetoxyimino)-4-(4-chlorophenylthio)-1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-1-butanone, etc.

[0060] Examples of the benzoin derivative include benzoin, benzoin methyl ether, benzoin ethyl ether, and benzoin isopropyl ether.

[0061] Examples of the acetophenone derivative include acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, and 1,1-dichloroacetophenone.

[0062] Examples of α-aminoacetophenone derivatives include 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one, 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholino)phenyl]-1-butanone, and N,N-dimethylaminoacetophenone.

[0063] Examples of the hydroxyacetophenone derivative include 2-hydroxy-1-(4-(4-(2-hydroxy-2-methylpropionyl)benzyl)phenyl)-2-methylpropane-1-one.

[0064] Examples of the anthraquinone derivative include 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, and 1-chloroanthraquinone.

[0065] Examples of the acylphosphine oxide compounds include 2,4,6-trimethylbenzoyldiphenylphosphine oxide, (2,4,6-trimethylbenzoyl)ethoxyphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, and bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide.

[0066] The content of the photopolymerization initiator in the photocurable resin composition is converted to solid content. When the total content of the multifunctional (meth)acrylate compound, the first monofunctional (meth)acrylate compound, and the second monofunctional (meth)acrylate compound is 100 parts by mass, the content of the photopolymerization initiator can be, for example, 1 part by mass or more and 20 parts by mass or less, preferably 1.5 parts by mass or more or 2 parts by mass or more, and more preferably 15 parts by mass or less or 10 parts by mass or less.

[0067] Other ingredients

[0068] The photocurable resin composition may further contain a thermosetting component as needed. Examples of thermosetting components include amino resins such as melamine resins, benzoguanamine resins, melamine derivatives, and benzoguanamine derivatives; isocyanate compounds and blocked isocyanate compounds; cyclohexanoate compounds; compounds having cyclic (thio)ether groups such as epoxy compounds and oxetane compounds; bismaleimide resins and carbodiimide resins; and thermosetting resins such as epoxy resins. Thermosetting components may be used alone or in combination of two or more.

[0069] When the photocurable resin composition contains a thermosetting component, the content of the thermosetting component in the photocurable resin composition, calculated as solid content, can be, for example, 10 parts by mass or less, preferably 5 parts by mass or less, and more preferably 1 part by mass or less, based on the total content of the multifunctional (meth)acrylate compound, the first monofunctional (meth)acrylate compound, and the second monofunctional (meth)acrylate compound being 100 parts by mass.

[0070] The photocurable resin composition may further contain an organic solvent as needed. Examples of the organic solvent include ketones, aromatic hydrocarbons, aliphatic hydrocarbons, glycol ethers, esters, and petroleum solvents. These organic solvents may be used alone or in combination of two or more.

[0071] When the photocurable resin composition contains an organic solvent, the content of the organic solvent in the photocurable resin composition, when the total content of the multifunctional (meth)acrylate compound, the first monofunctional (meth)acrylate compound, and the second monofunctional (meth)acrylate compound is 100 parts by mass, can be, for example, 10 parts by mass or less, preferably 5 parts by mass or less, and more preferably 1 part by mass or less.

[0072] The photocurable resin composition may further contain at least one colorant selected from the group consisting of dyes and pigments as needed. The colorant can be selected in color according to the intended purpose and may be any of white, black, or other colorants.

[0073] As a white coloring agent, white pigments can be cited. As white pigments, known white pigments such as titanium oxide, zinc oxide, magnesium oxide, zirconium oxide, aluminum oxide, barium sulfate, silicon dioxide, talc, mica, aluminum hydroxide, calcium silicate, aluminum silicate, hollow resin particles, and zinc sulfide can be used. Among them, titanium oxide is preferred due to its high coloring properties and reflectivity. These white pigments can be used alone or in combination of two or more.

[0074] Titanium oxide may have any structure of rutile, anatase, or ramsdellite, and may be used alone or in combination of two or more. Of the above structures, rutile titanium oxide is preferably used.

[0075] Examples of black colorants include inorganic pigments such as carbon black, ferrosoferric oxide (Fe₃O₄), black titanium oxide, zirconium nitride, copper manganese black, copper chrome black, and cobalt black, as well as organic pigments such as perylene black, lactone black, cyanine black, and aniline black. In addition to black pigments, dyes or pigments such as red, blue, green, and yellow, as described below, may be mixed to produce black or similar black-based colors. These black colorants may be used alone or in combination of two or more.

[0076] As colorants of other hues, pigments and dyes of red, blue, green, and yellow can be cited, and known colorants indicated by pigment indices can be used. For example, Pigment Blue 15, 15:1, 15:2, 15:3, 15:4, 15:6, 16, 60, Solvent Blue 35, 63, 68, 70, 83, 87, 94, 97, 122, 136, 67, 70, Pigment Green 7, 36, 3, 5, 20, 28, Solvent Yellow 163, Pigment Yellow 24, 108, 193, 147, 199, 202, 110, 109, 139, 179, 185, 93, 94, 95, 128, 155, 166, 180, 120, 151, 154, 156, 175, 181, 1, 2, 3, 4, 5, 6, 9, 10, 12, 61, 62, 62:1, 65, 73, 74, 75, 97, 100, 104, 105, 111, 116, 167, 168, 169, 182, 183, 12, 13, 14, 16, 17, 55, 63, 81, 83, 87, 126, 127, 152, 170, 172, 174, 176, 188, 198, Pigment Orange 1, 5, 13, 14, 16, 17, 24, 34, 36, 38, 40, 43, 46, 49, 51, 61, 63, 64, 71, 73, Red 1, 2, 3, 4, 5, 6, 8, 9, 12, 14, 15, 16, 17, 21, 22, 23, 31, 32, 112, 114, 146, 147, 151, 170, 184, 187, 188, 193, 210, 245, 253, 258, 266, 267, 268, 269, 37, 38, 41, 48:1, 48:2, 48:3, 48:4, 49:1, 49:2, 50:1, 52:1, 52:2, 53:1, 53:2, 57:1, 58:4, 63:1, 63:2, 64:1, 65: 8, 171, 175, 176, 185, 208, 123, 149, 166, 178, 179, 190, 194, 224, 254, 255, 264, 270, 272, 220, 144, 166, 214, 220, 221, 242, 168, 177, 216, 122, 202, 206, 207, 209, Solvent Red 135, 179, 149, 150, 52, 207, Pigment Violet 19, 23, 29, 32, 36, 38, 42, Solvent Violet 13, 36, Pigment Brown 23, 25, Pigment Black 1, 7, etc.

[0077] When the photocurable resin composition contains a colorant, the content thereof in terms of solid content may be 1 part by mass or more and 50 parts by mass or less relative to 100 parts by mass of the photocurable resin composition.

[0078] The photocurable resin composition may also contain, as needed: amine compounds; polymerization inhibitors such as hydroquinone, hydroquinone monomethyl ether, tert-butylcatechol, pyrrolidine, and phenothiazine; inorganic fillers such as zirconium oxide, barium titanate, clay, magnesium carbonate, calcium carbonate, aluminum hydroxide, and mica powder; thickeners such as micropowdered silica, organic bentonite, and montmorillonite; at least one of defoaming agents and leveling agents such as silicone, fluorine, and polymers; antioxidants, photopolymerization sensitizers, light stabilizers, dispersants, curing accelerators, flame retardants, flame retardant additives, and silane coupling agents.

[0079] The viscosity of the photocurable resin composition at 25°C can be, for example, 150 mPa·s or less. The viscosity of the photocurable resin composition at 25°C is preferably less than 80 mPa·s, less than 50 mPa·s, or less than 30 mPa·s. The viscosity of the photocurable resin composition at 25°C can also be 5 mPa·s or greater. Photocurable resin compositions having a viscosity within the above range are suitable for use in inkjet printers. Therefore, the photocurable resin composition can be used as an ink to directly draw patterns on substrates for printed wiring boards, etc.

[0080] Here, the viscosity of the photocurable resin composition is measured in accordance with the "Viscosity measurement method using a cone-plate type rotational viscometer" in JIS Z8803:2011 (10), at 25°C, 50 rpm, and 30 seconds using a cone-plate viscometer (TVe-33H, manufactured by Toki Sangyo Co., Ltd.) using a 1°34'×R24 cone rotor.

[0081] As an embodiment, the present invention may include a cured product. The cured product can be obtained by photoirradiating a resin composition layer comprising a photocurable resin composition to photocuring the resin composition layer. The photoirradiation can be performed by irradiation with active energy rays such as ultraviolet rays, electron rays, and chemical rays, preferably by ultraviolet irradiation. Ultraviolet irradiation in an inkjet printer can be performed, for example, by installing a light source such as a high-pressure mercury lamp, a metal halide lamp, or an ultraviolet LED on the side of the print head and scanning the print head or substrate. In this case, printing and ultraviolet irradiation can be performed almost simultaneously.

[0082] The cured product obtained from the photocurable resin composition also has excellent flexibility and is therefore particularly suitable as a solder resist for flexible printed wiring boards. Examples of substrates for flexible printed wiring boards include films made of glass polyimide, polyimide, polyethylene terephthalate, liquid crystal polymer, polycarbonate, and the like.

[0083] As one embodiment, the present invention may include an electronic component having a curved portion, wherein the curved portion includes a cured product. The electronic component herein refers to a component used in an electronic circuit and is an electronic component having a curved portion, including a printed wiring board, particularly a flexible printed wiring board. The cured product of the photocurable resin composition is suitable as an insulating cured coating film in the curved portion of these electronic components. Examples of substrates for flexible printed wiring boards include films made of glass polyimide, polyimide, polyethylene terephthalate, liquid crystal polymer, polycarbonate, and the like.

[0084] As one embodiment, the present invention may include a flexible display comprising a cured product. Examples of flexible displays include organic EL displays and flexible liquid crystal displays. Examples of organic EL displays include bottom-emission flexible organic EL displays and top-emission flexible organic EL displays. The cured product is suitable for use as a solder resist in a curved portion of a flexible printed wiring board constituting the flexible display.

[0085] [Example]

[0086] The present invention will be described in more detail below with reference to Examples, but the present invention is not limited to these Examples. "Parts" and "%" are by mass unless otherwise specified.

[0087] As materials for preparing a photocurable resin composition, the following materials were prepared.

[0088] (a) Multifunctional (meth)acrylate compounds

[0089] ARONIX (R) M-313: Isocyanuric acid EO-modified diacrylate and triacrylate (manufactured by Toagosei Co., Ltd.)

[0090] (b1) First monofunctional (meth)acrylate compound

[0091] ARONIX (R) M-140: N-acryloyloxyethyl hexahydrophthalimide (manufactured by Toagosei Co., Ltd.)

[0092] KRM9276: Urethane acrylate (manufactured by Daicel Chamox Co., Ltd.)

[0093] (b2) Second monofunctional (meth)acrylate compound

[0094] AOMA: 2-(allyloxymethyl)methyl acrylate (manufactured by Nippon Shokubai Co., Ltd.); viscosity at 25°C: 1.6 mPa·s

[0095] VEEA: 2-(2-vinyloxyethoxy)ethyl acrylate (manufactured by Nippon Shokubai Co., Ltd.); viscosity at 25°C: 3.7 mPa·s

[0096] CHDMMA: 1,4-cyclohexanedimethanol monoacrylate (manufactured by Mitsubishi Chemical Corporation); viscosity at 25°C: 88 mPa·s

[0097] (c) Photopolymerization initiator

[0098] TPO-L: (2,4,6-trimethylbenzoyl)ethoxyphenylphosphine oxide (manufactured by Agenmon Resins Pte Ltd)

[0099] other

[0100] KAYARAD UX-6101: Difunctional urethane acrylate (manufactured by Nippon Kayaku Co., Ltd.)

[0101] Preparation of photocurable resin composition

[0102] The components were mixed in the proportions (unit: parts by mass) shown in Table 1 below and stirred with a high-speed stirrer (room temperature, rotation speed 500 rpm, 5 minutes). Subsequently, a dispersion treatment was performed for 2 hours using a bead mill (conical K-8 (manufactured by Bühler Co., Ltd.) using zirconia beads (under the conditions of rotation speed 1200 rpm, ejection volume 20%, bead particle size 0.65 mm, and filling rate 88%) to obtain photocurable resin compositions (Examples 1 to 7) and photocurable resin compositions of comparative examples (Comparative Examples 1 to 4). In addition, "-" in the table indicates that no additives were added.

[0103] Elastic modulus and elongation at breaking point

[0104] The photocurable resin composition obtained above was applied to a copper foil substrate for evaluation so that the cured film had a thickness of 50 μm. An exposure device equipped with a high-pressure mercury lamp was used at a cumulative exposure dose of 1000 mJ / cm 2 The cured film was peeled off from the copper foil substrate and cut into pieces of 10 mm x 40 mm to prepare evaluation samples.

[0105] Evaluation samples were tensile tested using an Autograph AG-X (manufactured by Shimadzu Corporation) at a chuck distance of 20 mm and a speed of 1 mm / min. The stress at break, elongation at break (%), and elastic modulus (GPa) at 25°C were measured. The elastic modulus (GPa) was determined from the slope of the stress-strain curve for test stresses ranging from 2 MPa to 7 MPa. Furthermore, elongation at break (%) was calculated by dividing the distance (mm) until the evaluation sample broke by the chuck distance (20 mm).

[0106] Elongation at break (%) = distance until the evaluation sample breaks (mm) / distance between chucks (20 mm) × 100

[0107] The values ​​of the elongation at break and the elastic modulus are calculated values ​​based on the measured values ​​of the elongation at break and the elastic modulus, respectively, and the values ​​obtained by rounding off the calculation results to the first decimal place are described.

[0108] Mandrel test

[0109] The evaluation was performed using the cylindrical mandrel method according to JIS K-5600-5-1:1999. The photocurable resin composition obtained above was applied to a 25 μm thick PET substrate using a coater so that the cured film had a thickness of 50 μm. An exposure device equipped with a high-pressure mercury lamp was used at a cumulative exposure dose of 1000 mJ / cm 2 Curing was performed to obtain a laminate having a cured film formed on a PET substrate. The laminate was cut into 100 mm x 50 mm rectangles and the cured film was bent outward with a curvature radius of 2 mm and 4 mm. The laminate was bent 180° using a 2-second bend tester and held for 10 seconds. The presence of cracks in the cured film was then confirmed visually and under an optical microscope, and evaluated based on the following criteria. The results are shown in Table 1.

[0110] Evaluation Benchmarks

[0111] A: No cracks were confirmed.

[0112] B: No cracks were observed in a bend with a curvature radius of 4 mm, but cracks were observed in a bend with a curvature radius of 2 mm.

[0113] C: Cracks were observed by bending with a curvature radius of 4 mm and 2 mm.

[0114] Restorative

[0115] Using a stretch tester ST-1501 (manufactured by HIMU Electronics Co., Ltd.), a 10 mm × 40 mm × 50 μm sample for evaluation, prepared in the same manner as for the evaluation of elastic modulus and elongation at break, was stretched 10% and then recovered 100 times. Immediately after 100 repetitions of stretching, the sample length was measured, and the recovery (%) was calculated by dividing the measured sample length by the pre-measurement sample length.

[0116] Recovery (%) = Sample length after measurement / Sample length before measurement × 100

[0117] Viscosity

[0118] The viscosity of the photocurable resin composition was measured to evaluate its suitability for inkjet coating. The viscosity of the photocurable resin composition was measured at 25°C, 50 rpm, and 30 seconds using a cone-plate viscometer (TVe-33H, manufactured by Toki Sangyo Co., Ltd.) with a 1°34' x R24 cone rotor. The measured values ​​were evaluated according to the following criteria. The results are shown in Table 1.

[0119] Evaluation Benchmarks

[0120] A: Less than 30 mPa·s. Inkjet coating is possible.

[0121] B: 30 mPa·s or more and less than 50 mPa·s. Inkjet coating is possible.

[0122] C: 50 mPa·s or more and less than 80 mPa·s. The ink can be ejected from the inkjet head, but the coating quality is poor.

[0123] D: 80 mPa·s or more, inkjet coating cannot be performed.

[0124]

Table 1

[0125]

[0126]

[0127] The photocurable resin compositions described in the examples achieved good evaluation results in all categories. In Comparative Example 1, which did not contain a multifunctional acrylate containing an isocyanuric acid skeleton, the elastic modulus of the cured film was insufficient, and it could not fully recover after repeated stretching. The recovery was insufficient, making it unsuitable for protecting the surface of curved portions of flexible displays, etc., and unsuitable for applications requiring repeated bending. In Comparative Example 2, which did not contain a first monofunctional acrylate, the elongation at break was not sufficiently achieved, and good results were not obtained in the mandrel test. Therefore, the flexibility was insufficient, making it unsuitable for protecting curved portions of flexible displays, etc. In Comparative Example 3, which did not contain a second monofunctional acrylate, the elongation at break was not sufficiently achieved, and the flexibility was insufficient. In addition, due to reduced adhesion to the substrate, good results could not be obtained in the mandrel test, making it unsuitable for protecting curved portions of flexible displays, etc. In Comparative Example 4, which contained a difunctional urethane acrylate instead of the first monofunctional acrylate, the elongation at break was not sufficiently achieved, the flexibility was insufficient, the recovery was reduced, and it was unsuitable for applications requiring repeated bending. For example, this is considered to be due to the formation of three-dimensional crosslinks formed by difunctional urethane acrylate, which has lower rigidity (elastic modulus) than acrylate having an isocyanuric acid skeleton.

Claims

1. A photocurable resin composition, characterized in that Include: A polyfunctional (meth)acrylate compound (a) having an isocyanuric acid skeleton and a (meth)acryloyl group; a first monofunctional (meth)acrylate compound (b1) containing a nitrogen atom; a second monofunctional (meth)acrylate compound (b2) having at least one functional group selected from the group consisting of an ether bond, an epoxy group, and a hydroxyl group; and Photopolymerization initiator (c).

2. The photocurable resin composition according to claim 1, wherein The first monofunctional (meth)acrylate compound (b1) has at least one functional group selected from the group consisting of an amide bond, an imide bond, and a urethane bond.

3. The photocurable resin composition according to claim 1, wherein The viscosity of the second monofunctional (meth)acrylate compound (b2) at 25° C. is 100 mPa·s or less.

4. The photocurable resin composition according to claim 1, wherein The second monofunctional (meth)acrylate compound (b2) comprises at least one selected from the group consisting of allyloxymethyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, cyclic trimethylolpropane formal (meth)acrylate, (2-methyl-2-ethyl-1,3-dioxolane-4-yl)methyl (meth)acrylate, 2-(2-vinyloxyethoxy)ethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate glycidyl ether, and 1,4-cyclohexanedimethanol mono(meth)acrylate.

5. The photocurable resin composition according to claim 1, wherein The content of the polyfunctional (meth)acrylate compound (a) is 10 parts by mass or more and 50 parts by mass or less in 100 parts by mass of the total of the polyfunctional (meth)acrylate compound (a), the first monofunctional (meth)acrylate compound (b1), and the second monofunctional (meth)acrylate compound (b2).

6. The photocurable resin composition according to claim 1, wherein In 100 parts by mass of the total of the polyfunctional (meth)acrylate compound (a), the first monofunctional (meth)acrylate compound (b1), and the second monofunctional (meth)acrylate compound (b2), the total content of the first monofunctional (meth)acrylate compound (b1) and the second monofunctional (meth)acrylate compound (b2) is 40 parts by mass or more and 80 parts by mass or less.

7. The photocurable resin composition according to claim 1, wherein The viscosity at 25°C is 150 mPa·s or less.

8. A cured product, characterized in that: A cured product obtained by curing the photocurable resin composition according to any one of claims 1 to 7.

9. An electronic component, characterized in that A curved portion is provided, wherein the curved portion comprises the cured product according to claim 8.

10. A flexible display, characterized in that: The method comprises the cured product according to claim 8.

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