Active energy ray curable composition and cured product

Abstract

To provide an active energy ray-curable composition excellent in the bending strength of a cured product.SOLUTION: The active energy ray-curable composition contains: a monofunctional monomer (A1) comprising 4-(meth)acryloyl morpholine (A11) and / or N,N-dimethyl (meth)acrylamide (A12); a monofunctional (meth)acrylate (A2) with an aromatic ring; a radical polymerizable monomer (A3) represented by general formula (1); and a bifunctional monomer (B) with an aromatic ring.SELECTED DRAWING: None

Description

[Technical Field]

[0001] This invention relates to an active energy ray curable composition and a cured product thereof. [Background technology]

[0002] In recent years, there has been a growing demand for materials with high bending strength used in electronic devices. For example, to make touch panels used in smartphones and other devices thinner and lighter, improve transparency, and reduce material costs, cover-integrated touch panels have been developed in which touch sensors such as ITO are directly formed on the cover glass. Glass has the advantage of having a high elastic modulus, meaning it has high surface hardness and is resistant to scratches, but it is brittle and easily breaks, and if it breaks, the touch panel becomes unusable. Acrylic resin and polycarbonate resin sheets have been used as alternative cover materials to glass, but their low surface hardness makes them easily scratched, and they can also be brittle, potentially breaking from external impacts. There is a demand for materials with high elastic modulus and low brittleness, that is, materials with high bending strength, but the development of materials with sufficient bending strength has not yet been achieved. For example, Patent Document 1 discloses a cured product obtained by thermosetting a resin composition containing a silsesquioxane derivative and an epoxy resin containing an alicyclic skeleton. Furthermore, Patent Document 2 discloses a cured product obtained by photocuring a resin composition containing an adamantane derivative. Neither of the cured products disclosed in Patent Documents 1 and 2 have sufficient flexural strength. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Re-tabled publication No. 2016-076257 [Patent Document 2] Japanese Patent Publication No. 2012-246264 [Overview of the Initiative]

Problems to be Solved by the Invention

[0004] An object of the present invention is to provide an active energy ray-curable composition having excellent flexural strength of a cured product.

Means for Solving the Problems

[0005] As a result of investigations to achieve the above object, the present inventors have arrived at the present invention. That is, the present invention provides an active energy ray-curable composition containing a monofunctional monomer (A1) composed of 4-(meth)acryloylmorpholine (A11) and / or N,N-dimethyl(meth)acrylamide (A12), a monofunctional (meth)acrylate (A2) having an aromatic ring, a radically polymerizable monomer (A3) represented by the following general formula (1), and a bifunctional monomer (B) having an aromatic ring; and a cured product of the curable composition.

Chemical Formula

Advantages of the Invention

[0006] The cured product of the active energy ray-curable composition in the present invention exhibits the effect of excellent flexural strength.

Modes for Carrying Out the Invention

[0007] The active energy ray curable composition of the present invention (hereinafter sometimes simply referred to as the curable composition) is a curable composition containing a monofunctional monomer (A1) consisting of 4-(meth)acryloylmorpholine (A11) and / or N,N-dimethyl(meth)acrylamide (A12), a monofunctional (meth)acrylic acid ester (A2) having an aromatic ring, a radical polymerizable monomer (A3) represented by the following general formula (1), and a difunctional monomer (B) having an aromatic ring. In this invention, the notation "(meth)acrylate" means acrylate and / or methacrylate, the notation "(meth)acrylic" means acrylic and / or methacrylic, and the notation "(meth)acryloyl group" means acryloyl group and / or methacryloyl group.

[0008] The curable composition of the present invention comprises, as an essential component, a monofunctional monomer (A1) consisting of 4-(meth)acryloylmorpholine (A11) and / or N,N-dimethyl(meth)acrylamide (A12). Of 4-(meth)acryloylmorpholine and N,N-dimethyl(meth)acrylamide, 4-acryloylmorpholine is preferred from the viewpoint of the flexural strength of the cured product.

[0009] The curable composition of the present invention contains a monofunctional (meth)acrylic acid ester (A2) having an aromatic ring as an essential component. The glass transition temperature (hereinafter also referred to as Tg) of the homopolymer of the monofunctional (meth)acrylic acid ester (A2) is preferably 0 to 50°C, and more preferably 5 to 35°C, from the viewpoint of the flexural strength of the cured product.

[0010] The Tg of the homopolymer of the monofunctional (meth)acrylic acid ester (A2) mentioned above is the temperature at which the loss tangent (tanδ) shows its maximum value when the dynamic viscoelasticity of the cured product obtained by homopolymerizing the monomer is measured by the method described below. The same applies to the Tg of the homopolymer of the radical polymerizable monomer (A3) represented by general formula (1) described later.

[0011] <Method for measuring the Tg of homopolymers> As an initiator, for example, 1-hydroxycyclohexyl phenyl ketone [trade name "Irgacure 184", manufactured by BASF] was added at 3% by weight relative to the monomer, and then ultraviolet light was applied at 1000 mJ / cm² using an ultraviolet irradiation device. 2 Irradiate and cure the material to create a test piece measuring 40mm in length, 5mm in width, and 1mm in thickness. Using this test piece, measurements are taken with a dynamic viscoelasticity measuring device (e.g., Rheogel-E4000, manufactured by UBM Co., Ltd.) under the conditions of frequency: 10 Hz and heating rate: 4 °C / min to determine the temperature at which the loss tangent (tanδ) of the homopolymer reaches its maximum value (the Tg of the homopolymer).

[0012] Examples of the monofunctional (meth)acrylic acid ester (A2) include phenyl (meth)acrylate, benzyl (meth)acrylate, phenoxyethyl (meth)acrylate, phenoxy 2-methylethyl (meth)acrylate, phenoxyethoxyethyl (meth)acrylate, paracumylphenoxyethyl (meth)acrylate, phenoxybenzyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, phenylbenzyl (meth)acrylate, phenylphenoxyethyl acrylate, 2-acryloyloxyethylhexahydrophthalate, and monofunctional (meth)acrylic acid esters containing a fluorene skeleton.

[0013] Of the monofunctional (meth)acrylic acid esters (A2) having the aromatic ring, from the viewpoint of the flexural strength of the cured product, benzyl (meth)acrylate, phenoxyethyl (meth)acrylate, and phenylphenoxyethyl (meth)acrylate are preferred, and phenoxyethyl (meth)acrylate and phenylphenoxyethyl (meth)acrylate are more preferred.

[0014] The curable composition of the present invention contains, as an essential component, a radically polymerizable monomer (A3) represented by the following general formula (1). The Tg of the homopolymer of the radically polymerizable monomer (A3) is preferably 50 to 150°C, more preferably 75 to 140°C, from the viewpoint of the flexural strength of the cured product.

[0015] The Tg of the homopolymer of the radically polymerizable monomer (A3) is the same as that defined by the Tg of the homopolymer of the monofunctional (meth)acrylate (A2).

[0016] The radically polymerizable monomer (A3) is an α-(unsaturated alkoxyalkyl) acrylate having radical polymerizability represented by the following general formula (1).

[0017]

Chemical formula

[0018] In the general formula (1), R 1 represents a hydrogen atom or an organic group composed of an aliphatic hydrocarbon having 1 to 30 carbon atoms. R 2 , R 3 , R 4 , R 5 and R 6 are each independently a hydrogen atom or an organic group composed of an aliphatic hydrocarbon having 1 to 6 carbon atoms.

[0019] When the above R 1 is an organic group composed of an aliphatic hydrocarbon having 1 to 30 carbon atoms, the organic group may be linear, branched or cyclic. From the viewpoint of the flexural strength of the cured product, the preferred carbon number of the organic group is 1 to 18, more preferably 1 to 12, and still more preferably 1 to 8. Specifically, methyl group, ethyl group, propyl group, butyl group, amyl group, neopentyl group, hexyl group, octyl group, 2-ethylhexyl group, cyclohexyl group, cyclohexylmethyl group, isobornyl group, adamantyl group, dicyclopentanyl group and dicyclopentenyl group, etc. can be mentioned.

[0020] R 2 , R 3 , R 4 , R 5 and R 6 If the organic group consists of an aliphatic hydrocarbon having 1 to 6 carbon atoms, the organic group consisting of an aliphatic hydrocarbon having 1 to 6 carbon atoms may be linear or branched. Specifically, examples include methyl groups, ethyl groups, propyl groups, butyl groups, amyl groups, neopentyl groups, and hexyl groups.

[0021] A preferred embodiment of the α-(unsaturated alkoxyalkyl) acrylate represented by general formula (1) is, from the viewpoint of the flexural strength of the cured product, R 5 and R 6 A compound represented by the following general formula (2), wherein R is a hydrogen atom, and a more preferred embodiment is R 2 , R 3 , R 4 , R 5 and R 6 This is the case for α-allyloxymethyl acrylate, where both atoms are hydrogen atoms.

[0022] [ka]

[0023] In the above general formula (2), R 1 , R 2 , R 3 and R 4 These are R in general formula (1) 1 , R 2 , R 3 and R 4 It is similar to that.

[0024] The radical polymerizable monomer (A3) is one whose homopolymer Tg is 50°C to 150°C, specifically α-allyloxymethylacrylic acid, α-allyloxymethylacrylate methyl, α-allyloxymethylacrylate ethyl, α-allyloxymethylacrylate n-propyl, α-allyloxymethylacrylate i-propyl, α-allyloxymethylacrylate n-butyl, α-allyloxymethylacrylate s-butyl, α-allyloxymethylacrylate t-butyl, α-allyloxymethylacrylate n-pentyl, α-ally S-pentyl alpha-allyloxymethylacrylate, t-pentyl alpha-allyloxymethylacrylate, neopentyl alpha-allyloxymethylacrylate, n-hexyl alpha-allyloxymethylacrylate, s-hexyl alpha-allyloxymethylacrylate, n-heptyl alpha-allyloxymethylacrylate, n-octyl alpha-allyloxymethylacrylate, s-octyl alpha-allyloxymethylacrylate, t-octyl alpha-allyloxymethylacrylate, 2-ethylhexyl alpha-allyloxymethylacrylate, nonyl alpha-allyloxymethylacrylate, α - Decyl allyloxymethylacrylate, undecyl α-allyloxymethylacrylate, lauryl α-allyloxymethylacrylate, tridecyl α-allyloxymethylacrylate, myristyl α-allyloxymethylacrylate, pentadecyl α-allyloxymethylacrylate, cetyl α-allyloxymethylacrylate, heptadecyl α-allyloxymethylacrylate, stearyl α-allyloxymethylacrylate, nonadecyl α-allyloxymethylacrylate, eicosyl α-allyloxymethylacrylate, α-allyloxymethyl α-(allyloxymethyl)acrylate containing chain-like saturated hydrocarbon groups such as ceryl acrylate and α-allyloxymethyl acrylate melicyl, α-allyloxymethyl acrylate cyclopentyl, α-allyloxymethyl acrylate cyclopentylmethyl, α-allyloxymethyl acrylate cyclohexyl, α-allyloxymethyl acrylate cyclohexylmethyl, α-allyloxymethyl acrylate 4-methylcyclohexyl, α-allyloxymethyl acrylate 4-t-butylcyclohexyl, α-allyloxymethyl acrylate tricyclodecanyl,Examples include α-allyloxymethyl acrylates containing alicyclic hydrocarbon groups, such as isobornyl α-allyloxymethylacrylate, adamantyl α-allyloxymethylacrylate, dicyclopentanyl α-allyloxymethylacrylate, and dicyclopentenyl α-allyloxymethylacrylate.

[0025] The radical polymerizable monomer (A3) can be produced, for example, by the method disclosed in International Publication No. 2010 / 114077.

[0026] Of the radical polymerizable monomers (A3) mentioned above, from the viewpoint of the flexural strength of the cured product, the compound represented by the general formula (2) is preferred, and more preferably methyl α-allyloxymethylacrylate.

[0027] The curable composition of the present invention comprises, as an essential component, a difunctional monomer (B) having an aromatic ring. The difunctional monomer (B) having an aromatic ring is an ester of a polyhydric alcohol having an aromatic ring and (meth)acrylic acid, and / or an ester of an alkylene oxide adduct of a polyhydric alcohol having an aromatic ring and (meth)acrylic acid. The aromatic ring-containing difunctional monomer (B) is a monomer having two (meth)acryloyl groups.

[0028] Specific examples of difunctional monomers (B) having an aromatic ring include di(meth)acrylate of an alkylene oxide adduct of bisphenol A, di(meth)acrylate of an alkylene oxide adduct of 9,9-bis(4-hydroxyphenyl)fluorene, dimethylol tricyclodecane di(meth)acrylate, di(meth)acrylate of an alkylene oxide adduct of bisphenol F, di(meth)acrylic acid adduct of diglycidyl ether of bisphenol A, di(meth)acrylic acid adduct of diglycidyl ether of bisphenol F, and di(meth)acrylic acid adduct of diglycidyl ether of 9,9-bis(4-hydroxyphenyl)fluorene. Of these, from the viewpoint of the flexural strength of the cured product, the di(meth)acrylic acid adduct of diglycidyl ether of bisphenol A, the di(meth)acrylic acid adduct of diglycidyl ether of bisphenol F, and the di(meth)acrylic acid adduct of diglycidyl ether of 9,9-bis(4-hydroxyphenyl)fluorene are preferred, and the dimethacrylic acid adduct of diglycidyl ether of bisphenol A is even more preferred.

[0029] The curable composition of the present invention may contain monomers other than the monofunctional monomer (A1) consisting of 4-(meth)acryloylmorpholine (A11) and / or N,N-dimethyl(meth)acrylamide (A12), the monofunctional (meth)acrylic acid ester having an aromatic ring (A2), the radical polymerizable monomer (A3), and the difunctional monomer having an aromatic ring (B). Examples of monomers other than (A1), (A2), (A3), and (B) include (meth)acrylamide, N-methyl(meth)acrylamide, N-ethyl(meth)acrylamide, N-propyl(meth)acrylamide, Nn-butyl(meth)acrylamide, Nt-butyl(meth)acrylamide, N-butoxymethyl(meth)acrylamide, N-isopropyl(meth)acrylamide, N-methylol(meth)acrylamide, and N,N-diethyl(meth)acrylamide.

[0030] The curable composition of the present invention may contain an acylphosphine photopolymerization initiator (C). Examples of acylphosphine photopolymerization initiators (C) include 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 6-trimethylbenzoyldiphenylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, 2,4-diethylthioxanthone, and 2-isopropylthioxanthone. The curable composition of the present invention may further contain photopolymerization initiators other than the acylphosphine photopolymerization initiator (C), for example, at least one selected from the group consisting of benzoin compounds, acetophenone compounds, anthraquinone compounds, thioxanthone compounds, ketal compounds, benzophenone compounds, α-aminoalkylphenone compounds, and oxime ester compounds. The benzoin compound may include, for example, at least one selected from the group consisting of benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isobutyl ether, 2-hydroxy-2-methyl-1-phenylpropan-1-one, and 1-hydroxycyclohexylphenyl ketone. The acetophenone compound contains, for example, at least one selected from the group consisting of acetophenone, 2,2-diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 2-hydroxy-2-methylphenylpropan-1-one, diethoxyacetophenone, 1-hydroxycyclohexylphenyl ketone, and 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one. The anthraquinone compound contains, for example, at least one selected from the group consisting of 2-ethylanthraquinone, 2-t-butylanthraquinone, 2-chloroanthraquinone, and 2-amylanthraquinone. The thioxanthone compound contains, for example, at least one selected from the group consisting of 2,4-diethylthioxanthone, 2-isopropylthioxanthone, and 2-chlorothioxanthone. The ketal compound contains at least one selected from the group consisting of, for example, acetophenone dimethyl ketal and benzyl dimethyl ketal. The benzophenone compound contains at least one selected from the group consisting of, for example, benzophenone, 4-benzoyl-4'-methyldiphenyl sulfide and 4,4'-bismethylaminobenzophenone.The α-aminoalkylphenone compound contains at least one selected from the group consisting of, for example, 2-methyl-1-(4-methylthiophenyl)-2-morpholinopro-butanone-1 and 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone]. The oxime ester compound contains at least one selected from the group consisting of, for example, 1,2-octanedione, 1-[4-(phenylthio)-,2-(O-benzoyl oxime)] and ethanone-1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]-1-(O-acetyl oxime). These acylphosphine photopolymerization initiators (C) can be used individually or in combination of two or more. Of these, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 2,4-diethylthioxanthone, and 2-isopropylthioxanthone are preferred from the viewpoint of curability, and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide is more preferred.

[0031] The curable composition of the present invention may contain other additives as needed, as long as they do not impair the effects of the present invention. Examples of additives include mold release agents, antioxidants, hindered amine light stabilizers, UV absorbers, antistatic agents, colorants, polymerization inhibitors, chain transfer agents, fillers, surfactants, plasticizers, dispersants, and thixotropy-imparting agents (thickeners).

[0032] The viscosity of the curable composition of the present invention at 25°C is preferably 50 to 150 mPa·s or less, from the viewpoint of applicability when used as a resin sheet for optical components, etc. The viscosity is measured using a viscometer [VISCOMETER TV-25 manufactured by Toki Sangyo Co., Ltd.] under conditions of a rotation speed of 50 rpm and a temperature of 25°C.

[0033] The content of the monofunctional monomer (A1) consisting of 4-(meth)acryloylmorpholine (A11) and / or N,N-dimethyl(meth)acrylamide (A12) in the present invention is preferably 35 to 65% by weight, and more preferably 40 to 60% by weight, based on the total weight of (A1), (A2), (A3), and (B), from the viewpoint of achieving a high level of both the flexural modulus and flexural strength of the cured product. The content of the monofunctional (meth)acrylic acid ester (A2) having an aromatic ring in the present invention is preferably 1 to 10% by weight, and more preferably 5 to 10% by weight, based on the total weight of (A1), (A2), (A3), and (B), from the viewpoint of achieving a high level of both the flexural modulus and flexural strength of the cured product. The content of the radical polymerizable monomer (A3) in the present invention is preferably 1 to 10% by weight, and more preferably 5 to 10% by weight, based on the total weight of (A1), (A2), (A3), and (B), from the viewpoint of the flexural modulus and flexural strength of the cured product. The content of the aromatic ring-containing bifunctional monomer (B) of the present invention is preferably 15 to 45% by weight, and more preferably 15 to 40% by weight, based on the total weight of (A1), (A2), (A3), and (B) from the viewpoint of the flexural strength of the cured product. If the curable composition of the present invention contains monomers other than (A1), (A2), (A3), and (B), the total content of monomers other than (A1), (A2), (A3), and (B) is preferably 10% by weight or less, and more preferably 5% by weight or less, based on the total weight of (A1), (A2), (A3), and (B) from the viewpoint of the flexural modulus and flexural strength of the cured product.

[0034] In the present invention, the weight ratio [A1 / B] of (A1) to (B) is preferably 1 to 4.5, and more preferably 2 to 3, from the viewpoint of the flexural modulus and flexural strength of the cured product.

[0035] In the present invention, the content of the photopolymerization initiator (C) is preferably 1 to 10% by weight, and more preferably 2 to 5% by weight, based on the total weight of (A1), (A2), (A3), and (B), from the viewpoint of the flexural modulus and flexural strength of the cured product.

[0036] The active energy ray curable composition of the present invention can be produced by uniformly mixing a monofunctional monomer (A1) which is 4-(meth)acryloylmorpholine (A11) and / or N,N-dimethyl(meth)acrylamide (A12), a monofunctional (meth)acrylic acid ester having an aromatic ring (A2), a radical polymerizable monomer represented by general formula (1) (A3), and a bifunctional monomer having an aromatic ring (B), and optionally a photopolymerization initiator (C) and the aforementioned other additives, using a known mechanical mixing method (a method using a mechanical stirrer and a magnetic stirrer, etc.).

[0037] The following describes a method for producing a cured product by curing the curable composition of the present invention. The method for producing a cured product using the curable composition of the present invention is not particularly limited, but it can be obtained by curing the curable composition using a mold and then releasing it from the mold. More specific methods for manufacturing the cured product include the following: A frame made of a silicon spacer (2 mm thick) is placed on glass, and the resulting curable composition is poured into it. Then, it is cured by irradiation with active energy rays. The active energy rays in this invention include ultraviolet rays, electron beams, X-rays, infrared rays, and visible light. The active energy rays used for curing the active energy ray-curable composition of the present invention can be adjusted by selecting a photopolymerization initiator. When the aforementioned acylphosphine photopolymerization initiator (C) is used, photocuring is possible by irradiation with ultraviolet light having a wavelength of 200 to 700 nm, and it is preferable that curing is possible by irradiation with light (ultraviolet light) having a wavelength of 200 to 400 nm. As a light source that emits ultraviolet light, in addition to high-pressure mercury lamps, ultra-high-pressure mercury lamps, metal halide lamps and high-power metal halide lamps, etc. (Latest Trends in UV / EB Curing Technology, edited by Radtech Research Group, CMC Publishing, p. 138, 2006) and LEDs can be used. From the viewpoint of the bending strength of the cured product, metal halide lamps are preferred. When photocuring the active energy ray-curable composition of the present invention, the irradiation dose of active energy rays is preferably 1000 to 5000 mJ / cm² from the viewpoint of the curability of the composition and the flexibility of the cured product. 2 More preferably 2500 mJ / cm² 2 That is the case. When photocuring the active energy ray-curable composition of the present invention, the illuminance of the active energy rays is preferably 500 to 1000 mJ / cm² from the viewpoint of the curability of the composition and the flexibility of the cured product. 2 More preferably 600 mW / cm² 2 That is the case. The temperature during irradiation with active energy rays is preferably 20-30°C, and more preferably 22-27°C, from the viewpoint of curability of the composition and flexibility of the cured product.

[0038] The cured product of the curable composition of the present invention has excellent flexural strength and is therefore useful as various coating materials, casting materials, and molding materials for optical components and electrical / electronic components. Specifically, it is useful as a cover material for touch panels. [Examples]

[0039] The present invention will be further described below with reference to examples and comparative examples, but the present invention is not limited thereto.

[0040] Examples 1-11 and Comparative Examples 1-4 The materials were mixed together according to the formulations (parts by weight) listed in Table 1, and stirred in a disperser until homogeneous to obtain activated energy ray curable compositions (X-1) to (X-11) and comparative curable compositions (Z-1) to (Z-4). The results of their evaluation are shown in Table 1.

[0041] <Preparation of bending test specimens> A frame measuring 2 mm thick, 60 mm long, and 20 mm wide, made from a silicon spacer, was placed on the glass, and the obtained activated energy ray-curable composition was poured into each frame. The irradiation was performed using a UV irradiation device at 22-27°C, 30-60% RH, and a metal halide lamp at an irradiance of 600 mW / cm². 2, cumulative light intensity 2500 mJ / cm 2 The active energy ray-curable composition was cured by irradiation under these conditions, and the cured product was removed from the mold.

[0042] <Bending strength test (flexural modulus and bending strength)> The specimens for the bending strength test were prepared by processing the cured material, which was prepared under the above conditions, to a thickness of 2 mm, a length of 50 mm, and a width of 5 mm. The bending strength test was conducted in accordance with JIS K 6911:2006, except that the support distance was 30 ± 0.5 mm and the bending speed was 10 mm / min. The bending strength and bending modulus of the obtained cured material are shown in Table 1. A flexural modulus of the cured product of the curable composition is considered good if it is 4000 MPa or higher, and a flexural strength of the cured product is considered good if it is 200 MPa or higher.

[0043] [Viscosity evaluation] The viscosity in this invention was measured using a viscosity measuring device [VISCOMETER TV-25 manufactured by Toki Sangyo Co., Ltd.] under conditions of a rotation speed of 50 rpm and a temperature of 25°C. A viscosity of 60 to 100 mPa·s is considered low viscosity and is preferable.

[0044] [Table 1]

[0045] The details of the raw materials represented by the symbols in Table 1 are as follows: (A11-1): 4-Acryloylmorpholine [ACMO: Manufactured by KJ Chemicals Co., Ltd.] (A12-1): N,N-dimethyldimethylacrylamide [DMAA: Manufactured by KJ Chemicals Co., Ltd.] (A1'-1): Isobornyl acrylate [IBXA: Manufactured by Osaka Organic Chemical Industry Co., Ltd.] (A2-1): Phenoxyethyl acrylate [PO-A: manufactured by Kyoeisha Chemical Co., Ltd.], Tg of homopolymer: 7℃ (A2-2): Phenylphenoxyethyl acrylate [OPPEA: manufactured by Shin-Nakamura Chemical Industry Co., Ltd.], Tg of homopolymer: 33℃ (A3-1): α-Allyloxymethylacrylate ["AOMA (registered trademark): Manufactured by Nippon Shokubai Co., Ltd."] (R 1 is a methyl group, R 2 , R 3 , R 4 , R 5 and R 6 (Hydrogen atoms), Tg of homopolymer: 84℃ (B-1): Bis-GMA (Methacrylic acid adduct of bisphenol A diglycidyl ether) [Epoxy ester 3000MK: Manufactured by Kyoeisha Chemical Co., Ltd.] (B-2): Bis-GA (Acrylic acid adduct of bisphenol A diglycidyl ether) [Epoxy ester 3000A: Manufactured by Kyoeisha Chemical Co., Ltd.] (B-3): FGDA (methacrylate adduct of 9,9-bis(4-hydroxyphenyl)ful orange glycidyl ether) (B'-1): Dimethylol tricyclodecanediaacrylate [DCP-A: Manufactured by Kyoeisha Chemical Co., Ltd.]

[0046] As shown in Table 1, the active energy ray curable compositions of Examples 1 to 11 of the present invention had low viscosity, and their cured products exhibited excellent flexural strength. On the other hand, the cured products of the active energy ray curable compositions of Comparative Examples 1 to 4 exhibited inferior flexural strength. [Industrial applicability]

[0047] The cured product of the curable composition of the present invention exhibits excellent flexural strength and is therefore useful as various coating materials, casting materials, and molded materials for optical and electrical / electronic components. Specifically, it is useful as a cover material for touch panels.

Claims

1. An active energy ray curable composition containing a monofunctional monomer (A1) consisting of 4-(meth)acryloylmorpholine (A11) and / or N,N-dimethyl(meth)acrylamide (A12), a monofunctional (meth)acrylic acid ester (A2) having an aromatic ring, a radical polymerizable monomer (A3) represented by the following general formula (1), and a bifunctional monomer (B) having an aromatic ring, wherein the viscosity at 25°C is 50 to 150 mPa·s. 【Chemistry 1】 [In formula (1), R １ R is an organic group consisting of a hydrogen atom or a monovalent aliphatic hydrocarbon having 1 to 30 carbon atoms. ２ , R ３ , R ４ , R ５ and R ６ Each of these is an organic group consisting of either a hydrogen atom or an aliphatic hydrocarbon having 1 to 6 carbon atoms.

2. The active energy ray curable composition according to claim 1, wherein the weight ratio [A1 / B] of (A1) to (B) is 1 to 4.

5.

3. The active energy ray curable composition according to claim 1 or 2, wherein the radical polymerizable monomer (A3) represented by the general formula (1) is methyl α-allyloxymethylacrylate.

4. A cured product obtained by curing the active energy ray curable composition according to claim 1 or 2.

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