(Meth)acrylate compounds, photocurable resin compositions, and their cured products

Abstract

The present invention aims to provide (meth)acrylate compounds and resin compositions that exhibit excellent adhesion to substrates and curability, and that yield a cured film with a high refractive index. [Solution] A (meth)acrylate compound (A) having at least one group selected from the group of formulas (a3) ​​and (a4) is provided. TIFF2026165911000010.tif29170 (In the formula, each X independently represents an aromatic ring which may have substituents, and R 7 ,R 8 Each of these independently represents a linear or branched chain, aliphatic ring, or aromatic ring of 1 to 20 hydrogen atoms or carbon atoms.

Description

[Technical Field]

[0001] This invention relates to (meth)acrylate compounds, photocurable resin compositions, and cured products thereof.

[0002] The (meth)acrylate compound of the present invention has substrate adhesion, curability, and a high refractive index, and can therefore be used as a lens forming material for photopolymerization materials and display elements, as well as an overcoat agent, adhesives, and as a wiring protection and insulating material for electronic materials. [Background technology]

[0003] Polyfunctional (meth)acrylate compounds are known to harden with light or heat and are widely used in coating materials, three-dimensional photopolymerization materials, wiring protection materials, and insulating materials. Recently, they have also been found to contribute to improved brightness and reduced energy consumption by forming microlenses as light extraction layers in image display devices. Compounds containing aromatic heterocycles are known to have high refractive indices and exhibit easy polymerization. However, even higher refractive indices are required to further improve brightness. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2024-022622 [Patent Document 2] Japanese Patent Publication No. 2024-036282 [Patent Document 3] Japanese Patent Publication No. 2024-175683 [Overview of the project] [Problems that the invention aims to solve]

[0005] The present invention aims to provide (meth)acrylate compounds and resin compositions thereof that exhibit excellent adhesion to substrates and curability, and that yield a cured film with a high refractive index. [Means for solving the problem]

[0006] To solve the aforementioned problems, the present inventors conducted diligent research and found that a (meth)acrylate compound (A) having a specific bonding site and a resin composition containing the (meth)acrylate compound (A) solve the aforementioned problems, thus arriving at the present invention. In other words, the present invention relates to the following:

[0007] [1] (A) A (meth)acrylate compound having at least one group selected from the group of formulas (a1) and (a2) below.

[0008] [ka]

[0009] (In the formula, each X independently represents an aromatic ring which may have substituents, and R 1 or R 2 These are independently represented by (b1) and (b2), and R 3 R represents a divalent organic group containing an oxygen atom. 4 R represents a hydrogen or methyl group. 5 is represented by hydrogen or (c), R 6 (* represents a divalent organic group. * indicates a bonding site.) [2] The (meth)acrylate compound (A) described in [1], wherein the aromatic ring is selected from the group consisting of a benzothiazole ring, a benzimidazole ring, a benzoxazole ring, and a naphthalene ring. [3] (A) an (meth)acrylate compound according to [1] or [2], wherein formula (a1) is the following formula (a3) ​​and (a2) is the following formula (a4).

[0010] [ka]

[0011] (R in the formula 7 ,R 8each independently represents hydrogen, or a linear or branched chain, aliphatic ring or aromatic ring having 1 to 20 carbon atoms.) [4] A photocurable resin composition comprising the (meth)acrylate compound (A) according to any one of claims [1] to [3] and a photopolymerization initiator (B). [5] A cured product formed using the photocurable resin composition according to claim [4], having a refractive index of 1.60 or more at a wavelength of 589.

Effects of the Invention

[0012] The resin composition of the present invention can achieve a high refractive index of the cured product, can provide a cured resin composition excellent in substrate adhesion and curability, and can be suitably used for materials requiring the above properties.

Modes for Carrying Out the Invention

[0013] The present invention relates to a (meth)acrylate compound (A) having at least one group selected from the group of the following formulas (a1) and (a2).

[0014]

Chemical Formula

[0015] (In the formula, X each independently represents an optionally substituted aromatic ring, R 1 or R 2 each independently is represented by (b1) or (b2), R 3 represents a divalent organic group containing an oxygen atom, R 4 represents hydrogen or a methyl group. R 5 is hydrogen or represented by (c), R 6 represents a divalent organic group. * indicates a bonding site)

[0016] When the aromatic ring is a hydrocarbon ring, examples include aromatic hydrocarbon rings having 6 to 14 carbon atoms, preferably 6 to 12, such as benzene rings, indene rings, naphthalene rings, azulene rings, fluorene rings, acenaphthylene rings, anthracene rings, phenanthrene rings, and pyrene rings. Particularly preferred are aromatic hydrocarbon rings having 6 to 10 carbon atoms, such as benzene rings and naphthalene rings, from the viewpoint of avoiding discoloration and ensuring solubility.

[0017] When the aromatic ring is a heterocycle, the heteroatom is not particularly limited and any atom such as S, O, N, or P can be used. However, from the viewpoint of ensuring compatibility, S, O, and N atoms are preferred, and from the viewpoint of avoiding discoloration and ensuring solubility, the number of heteroatoms in the molecule is preferably 1 to 3. Specifically, examples include aromatic heterocycles having 2 to 18 carbon atoms, preferably 3 to 6, such as furan rings, thiophene rings, pyrrole rings, imidazole rings, triazole rings, pyrazole rings, pyridine rings, pyrimidine rings, pyrazine rings, triazine rings, oxazole rings, thiazole rings, benzofuran rings, benzothiophene rings, indole rings, isoindole rings, benzimidazole rings, benzothiazole rings, benzoxazole rings, quinoline rings, isoquinoline rings, quinoxaline rings, dibenzofuran rings, dibenzothiophene rings, carbazole rings, thianthrene rings, dibenzothioxane rings, dibenzobenzothiophene rings, oxazolidine rings, and thiazolidinedion rings. In order to maintain a high refractive index while keeping the size of the rings in the overall compound small, benzothiazole rings, benzimidazole rings, and benzoxazole rings are preferred.

[0018] The substituents that the aromatic ring may have include alkyl groups, alkoxy groups, and aryl groups. From the viewpoint of solubility, unsubstituted or methyl groups are preferred.

[0019] In the above formula, R 1 , R 2 These are represented independently by (b1) and (b2), and from the viewpoint of curability, it is preferable to include at least one (b1) in each sentence.

[0020] R 3The symbol represents a divalent organic group containing an oxygen atom. Examples of divalent organic groups containing an oxygen atom include divalent hydrocarbon groups which may have substituents, or groups which include a divalent hydrocarbon group which may have substituents and a bond such as -O-, -COO-, -CO-, -NH-, -S-, -SO-, -SO2-, etc.

[0021] The group comprising a divalent hydrocarbon group which may have the above substituents and a bond such as -O-, -COO-, -CO-, -NH-, -S-, -SO-, -SO2- may contain only one type of divalent hydrocarbon group or one type of the above bond, or it may contain two or more types. The above bond is preferably at least one type selected from the group consisting of -O-, -CO-, -NH-, and -COO-, in terms of curability and high refractive index.

[0022] It is preferable that formula (a1) is the following formula (a3) ​​and (a2) is the following formula (a4).

[0023] [ka]

[0024] (R in the formula 7 ,R 8 Each of these independently represents a linear or branched chain, aliphatic ring, or aromatic ring of 1 to 20 hydrogen atoms or carbon atoms.

[0025] Examples of the linear or branched hydrocarbon groups mentioned above include aliphatic hydrocarbon groups. Examples of aliphatic hydrocarbon groups include alkylene groups such as methylene, ethylene, propylene, isopropylene, butylene, isobutylene, t-butylene, pentylene, neopentylene, hexamethylene, heptylene, octylene, 2-ethylhexylene, nonylene, decylene, undecylene, and dodecylene; alkenylene groups such as vinylene, propenylene, isopropenylene, butenylene, butadienylene, pentenylene, hexenylene, and heptenylene; and alkylene groups such as ethynylene, propynylene, 1-butylylene, and 2-butylylene.

[0026] Examples of the aliphatic or aromatic rings mentioned above include cycloalkylene groups such as cyclopropylene, cyclobutylene, cyclopentylene, cyclohexylene, norbornylene, adamantylene, tricyclodecanylene, and tetracyclodecanylene; cycloalkenylene groups such as cyclopropenylene, cyclobutenylene, cyclohexenylene, and cyclopentenylene; cycloalkylidene groups such as cyclopentylidene and cyclohexylidene; and arylene groups such as phenylene, torylene, and naphthylene.

[0027] From the viewpoint of solubility and high refractive index, R 7 , R 8 Hydrogen or an aromatic ring is preferred.

[0028] R 6 This represents a divalent organic group, which may have a linear, branched, aliphatic, or aromatic ring structure.

[0029] The molecular weight of the (meth)acrylate compound (A) is preferably 100 to 3000 from the viewpoint of curability and solvent solubility, and more specifically, 200 to 2500.

[0030] The photopolymerization initiator used in the photocurable resin composition of the present invention can be used without particular limitations, but specifically, for example, benzoins such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, and benzoin isobutyl ether; acetophenones such as acetophenone, 2,2-diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 2-hydroxy-2-methyl-phenylpropan-1-one, diethoxyacetophenone, 1-hydroxychlorohexylphenyl ketone, and 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one (for example, Omnirad-907 described in the examples below); 2-ethylanthraquinone, 2 Examples include anthraquinones such as tert-butylanthraquinone, 2-chloroanthraquinone, and 2-amylanthraquinone; thioxanthones such as 2,4-diethylthioxanthone (e.g., DETX-S described in the examples below), 2-isopropylthioxanthone, and 2-chlorothioxanthone; ketals such as acetophenone dimethyl ketal and benzyl dimethyl ketal; benzophenones such as benzophenone, 4-benzoyl-4'-methyldiphenyl sulfide, and 4,4'-bismethylaminobenzophenone; and phosphine oxides such as 2,4,6-trimethylbenzoyldiphenylphosphine oxide and bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide. The photopolymerization initiator (C) may be used alone or in combination of two or more types. The content ratio in these photosensitive resin compositions is typically 0.1 to 20% by mass, preferably 0.2 to 10% by mass, when the solid content of the photocurable resin composition is taken as 100% by mass.

[0031] These photopolymerization initiators (C) can be used alone or as a mixture of two or more, and can also be used in combination with accelerators such as tertiary amines like triethanolamine and methyldiethanolamine, and benzoic acid derivatives such as ethyl N,N-dimethylaminobenzoate and isoamyl N,N-dimethylaminobenzoate. The amount of these accelerators added is preferably 100% by mass or less relative to the photopolymerization initiator (C).

[0032] The resin composition of the present invention can be diluted with an organic solvent as needed, and suitable solvents include, for example, the following: alcohols such as methanol and ethanol; ethers such as tetrahydrofuran; glycol ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol dimethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, and diethylene glycol monobutyl ether; methyl cellosolve acetate, ethyl cellosolve acetate, butyl cellosolve acetate, and propylene glycol methyl ether acetate. Alkylene glycol monoalkyl ether acetates such as 3-methoxybutyl-1-acetate; aromatic hydrocarbons such as toluene and xylene; ketones such as methyl ethyl ketone, methyl isobutyl ketone, methyl amyl ketone, cyclohexanone, and 4-hydroxy-4-methyl-2-pentanone; and esters such as ethyl 2-hydroxypropionate, methyl 2-hydroxy-2-methylpropionate, ethyl 2-hydroxy-2-methylpropionate, ethyl ethoxyacetate, ethyl hydroxyacetate, methyl 2-hydroxy-2-methylbutanoate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, methyl 3-ethoxypropionate, ethyl 3-ethoxypropionate, ethyl 3-ethoxypropionate, ethyl ethyl acetate, butyl acetate, methyl lactate, and ethyl lactate. These solvents may be used individually or in mixtures of two or more.

[0033] Furthermore, the resin composition of the present invention may optionally contain thermosetting resins, antioxidants, polymerization inhibitors, inorganic fillers, organic fillers, surfactants, adhesive aids, etc.

[0034] Furthermore, the resin composition of the present invention may contain other components as needed.

[0035] Other components that can react with component (A) and crosslink are also possible from the viewpoint of curability and film density. Examples include (meth)acryloyl group-containing compounds, chain vinyl group-containing compounds, aromatic vinyl group-containing compounds, maleimide group-containing compounds, epoxy group-containing compounds, phenol group-containing compounds, isocyanate group-containing compounds, cyanate group-containing compounds, etc.

[0036] This resin composition may further contain inorganic fillers, organic fillers, adhesive aids, surfactants, antioxidants, tackifiers, defoamers, plasticizers, UV absorbers, flame retardants, dyes, and the like.

[0037] Examples of inorganic fillers include silicon dioxide, silicon oxide, calcium carbonate, calcium silicate, magnesium carbonate, magnesium oxide, titanium dioxide, zirconium oxide, talc, kaolin clay, calcined clay, zinc oxide, zinc sulfate, aluminum hydroxyl, aluminum oxide, glass, mica, barium sulfate, alumina white, zeolite, silica balloons, glass balloons, etc. These inorganic fillers can also be given functional groups such as halogen groups, epoxy groups, hydroxyl groups, and thiol groups by adding and reacting silane coupling agents, titanate-based coupling agents, aluminum-based coupling agents, zirconate-based coupling agents, etc.

[0038] Examples of organic fillers include benzoguanamine resin, silicone resin, low-density polyethylene, high-density polyethylene, polyolefin resin, ethylene-acrylic acid copolymer, polystyrene, acrylic copolymer, polymethyl methacrylate resin, fluororesin, nylon 12, nylon 6 / 66, phenolic resin, epoxy resin, urethane resin, polyimide resin, organic pigments, and organic dyes.

[0039] Examples of adhesive aids include silane coupling agents and metal chelates. These include silane coupling agents such as γ-glycidoxypropyltrimethoxysilane or γ-chloropropyltrimethoxysilane; titanate coupling agents such as tetra(2,2-diallyloxymethyl-1-butyl)bis(ditridecyl)phosphite titanate and bis(dioctylpyrophosphate)ethylene titanate; aluminum coupling agents such as acetalkoxyaluminum diisopropylate; and zirconium coupling agents such as acetylacetone zirconium complexes.

[0040] Surfactants can be used to improve the applicability (wetting spread and reduction of uneven application) of the composition of the present invention. Examples of surfactants include fluorine-based surfactants, silicone-based surfactants, and nonionic surfactants.

[0041] Examples of antioxidants include hindered phenol antioxidants, phosphite ester antioxidants, and thioether antioxidants.

[0042] Any tackifier, defoamer, plasticizer, ultraviolet absorber, flame retardant, and dye that can be used in the photocurable resin composition of the present invention can be used without particular limitation, provided that they are known and commonly used, as long as they do not impair the curability and resin properties.

[0043] To obtain the photocurable resin composition of the present invention, the above-mentioned components can be mixed, and the order and method of mixing are not particularly limited. [Examples]

[0044] Next, the present invention will be described in more detail with reference to examples. However, the present invention is not limited in any way by the following examples.

[0045] Example 1 In a 300 mL flask equipped with a stirrer and reflux tubing, 30.3 g of propylene glycol methyl ether acetate, 23.6 g of RE-310S (bisphenol A type epoxy resin, Nippon Kayaku Co., Ltd.), and 21.9 g of mercaptobenzothiazole were added and stirred at 100°C for 10 hours. To the resulting thiol-modified resin, 11.6 g of propylene glycol methyl ether acetate, 0.12 g of dibutyl tert-cresol, and 17.5 g of AOI (2-isocyanatoethyl acrylate, Resonaq Co., Ltd.) were added and mixed and stirred at 100°C for 20 hours to obtain 100 g of acrylate compound (A1).

[0046] Example 2 In a 300 mL flask equipped with a stirrer and reflux tubing, 32.0 g of propylene glycol methyl ether acetate, 29.5 g of WHR-991S (phenolphthaleimidine type epoxy resin, Nippon Kayaku Co., Ltd.), and 18.5 g of mercaptobenzothiazole were added and mixed at 100°C for 10 hours. To the resulting thiol-modified resin, 9.8 g of propylene glycol methyl ether acetate, 0.12 g of dibutyl tert-cresol, and 14.8 g of AOI (2-isocyanatoethyl acrylate, Resonaq Co., Ltd.) were added and mixed and stirred at 100°C for 20 hours to obtain 100 g of acrylate compound (A2).

[0047] Example 3 In a 300 mL flask equipped with a stirrer and reflux tubing, 30.5 g of propylene glycol methyl ether acetate, 25.1 g of YX-4000H (tetramethyl biphenyl type epoxy resin, Mitsubishi Chemical Corporation), and 20.6 g of 2-naphthothiol were added and stirred at 100°C for 10 hours. To the resulting thiol-modified resin, 11.5 g of propylene glycol methyl ether acetate, 0.12 g of dibutyl tertiary cresol, and 17.2 g of AOI (2-isocyanatoethyl acrylate, Resonaq Corporation) were added and mixed and stirred at 100°C for 20 hours to obtain 100 g of acrylate compound (A3).

[0048] Example 4 In a 300 mL flask equipped with a stirrer and reflux tubing, 32.4 g of propylene glycol methyl ether acetate, 30.7 g of Ogusol EG-200 (fluorene skeleton epoxy resin, Osaka Gas Chemical Co., Ltd.), and 17.9 g of mercaptobenzothiazole were added and stirred at 100°C for 10 hours. To the resulting thiol-modified resin, 9.5 g of propylene glycol methyl ether acetate, 0.12 g of dibutyl tert-cresol, and 13.3 g of acrylic anhydride were added and mixed and stirred at 100°C for 20 hours. Unreacted raw materials were removed by vacuum distillation, and propylene glycol methyl ether acetate was added to dilute the mixture to obtain 100 g of acrylate compound (A4).

[0049] Comparative Example 1 Compound (A5) of Synthesis Example 1 was synthesized according to the method described in paragraph 0013 of Japanese Patent Application Publication No. 2024-175683.

[0050] Comparative Example 2 In a 300 mL flask equipped with a stirrer and reflux tubing, 39.9 g of propylene glycol methyl ether acetate, 32.6 g of DPHA (dipentaerythritol penta / hexaacrylate mixture, Nippon Kayaku Co., Ltd.), and 27.3 g of mercaptobenzothiazole were added, and the mixture was stirred at 100°C for 10 hours to synthesize acrylate compound (A6).

[0051] Comparative Example 3 DPHA (dipentaerythritol penta / hexaacrylate mixture, Nippon Kayaku Co., Ltd.) was used.

[0052] [Method for measuring and evaluating the refractive index nD of liquids] Table 1 shows the refractive indices of the compounds used in the examples and comparative examples, as well as compounds (A1) to (A6). The refractive index was calculated by preparing samples diluted with solvent at three different concentrations, measuring the refractive index at these three points, and then calculating the refractive index of the compound itself.

[0053] [Table 1]

[0054] Measurement device: Multi-wavelength Abbe refractometer DR-M2, manufactured by Atago Corporation. Measurement wavelength: 589nm (D line)

[0055] The photocurable resin compositions for Examples 5-7 and Comparative Example 4 were prepared by blending the materials in the amounts (parts by mass) shown in Table 2.

[0056] [Table 2]

[0057] <Photopolymerization initiator> Irgacure907: 2-methyl-1-[(4-methylthio)phenyl]-2-morpholinopropan-1-one

[0058] <Curing the hardened film> The prepared resin composition was spin-coated onto a glass substrate and heated at 80°C for 10 minutes to form a coating with a thickness of 5 to 15 μm. The resulting coating was then treated with an ultraviolet irradiator (USHIO ultra-high pressure mercury lamp) at a rate of 100 mJ / cm². 2 A cured film was obtained by irradiating it with ultraviolet light using this energy.

[0059] [Post-hardening tack] The prepared curable resin composition and cured film were touched with a finger to check for tackiness. ○: Not sticky, ×: Sticky

[0060] [Adhesion to substrate] Following JIS K5400, 11 vertical and 11 horizontal cuts were made on the surface of the film at 1mm intervals to create 100 grid squares. After applying cellophane tape to the surface and peeling it off in one swift motion, the number of squares that remained intact was indicated.

[0061] [Table 3] [Industrial applicability]

[0062] The (meth)acrylate compound of the present invention has high refractive index and can be used to obtain a cured film with excellent curability and adhesion to the substrate. Therefore, resin compositions containing the (meth)acrylate compound of the present invention can be suitably used in microlenses for image display devices, overcoat agents, resin compositions for stereolithography, electronic materials for wiring protection materials and insulating film materials, and the like.

Claims

1. (A) A (meth)acrylate compound having at least one group selected from the group of formulas (a1) and (a2) below. 【Chemistry 1】 (In the formula, each X independently represents an aromatic ring which may have substituents, and R １ is R ２ These are independently represented by (b1) and (b2), and R ３ R represents a divalent organic group containing an oxygen atom. ４ R represents a hydrogen or methyl group. ５ is represented by hydrogen or (c), R ６ (The symbol represents a divalent organic group. * indicates a bonding site.)

2. The (meth)acrylate compound (A) according to claim 1, wherein the aromatic ring is selected from the group consisting of a benzothiazole ring, a benzimidazole ring, a benzoxazole ring, and a naphthalene ring.

3. The (meth)acrylate compound (A) according to claim 1, wherein formula (a1) is the following formula (a3) ​​and formula (a2) is the following formula (a4). 【Chemistry 2】 (In the formula R ７ , R ８ Each of these independently represents a linear or branched chain, aliphatic ring, or aromatic ring of 1 to 20 hydrogen atoms or carbon atoms.

4. A photocurable resin composition comprising the (meth)acrylate compound (A) and a photopolymerization initiator (B) according to claim 1.

5. A cured product formed using the photocurable resin composition described in claim 4, wherein the refractive index at a wavelength of 589 is 1.60 or higher.

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