Active energy ray-curable composition and cured product

Abstract

An active energy ray-curable composition which contains (A) a monofunctional monomer that contains (A1) a monofunctional monomer having a homopolymer glass transition temperature of less than 25 DEG C and (A2) a monofunctional monomer having a homopolymer glass transition temperature of 25 DEG C or more, (C) a polyfunctional (meth) acrylate having a number average molecular weight of 500-40,000, and (D) a photopolymerization initiator, and wherein: the monofunctional monomer (A) contains (A1) a monofunctional monomer having a homopolymer glass transition temperature of less than 25 DEG C and (A2) a monofunctional monomer having a homopolymer glass transition temperature of 25 DEG C or more; based on the total weight of the monofunctional monomer (A) and the polyfunctional (meth) acrylate (C), the content of the monofunctional monomer (A) is 10-75 wt%, the content of the polyfunctional (meth) acrylate (C) is 25-90 wt%, the content of the photopolymerization initiator (D) is 0.1-20 wt%, and the molecular weight between crosslinking points is 1000-25000.

Description

Technical Field

[0001] The present invention relates to an active energy ray curable composition and a cured product thereof. Background Art

[0002] In recent years, the development of so-called flexible displays that can be bent and stretchable stretchable devices has been actively carried out. Correspondingly, as materials, stretchable properties are required such that they do not break even when bent and do not cause peeling between components. In addition, an active energy ray curable composition having a low viscosity at room temperature can be applied to various coating methods including an inkjet method, and is used as a material for electronic components, optical components, etc. that require high-precision coating. Further, a soft material that can be pasted onto a curved surface of a display or the like is desired. Conventionally, although there has been an extensible UV resin, there have been problems such as poor recovery rate, poor flexibility, high elastic modulus, and peeling from other substrates when stretching the device (Patent Document 1).

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2020-70338 Summary of the Invention

[0006] Problems to be Solved by the Invention

[0007] An object of the present invention is to provide an active energy ray curable composition that can provide a cured product having excellent flexibility and stretchability.

[0008] Means for Solving the Problems

[0009] The inventors of the present invention conducted intensive studies to solve the above problems, and as a result, completed the present invention.

[0010] That is, the present invention relates to an active energy ray curable composition containing a monofunctional monomer (A), a polyfunctional (meth)acrylate (C) having a number average molecular weight of 500 to 40,000, and a photopolymerization initiator (D), wherein the monofunctional monomer (A) contains a monofunctional monomer (A1) having a glass transition temperature of a homopolymer lower than 25°C and a monofunctional monomer (A2) having a glass transition temperature of a homopolymer of 25°C or higher. Based on the total weight of the monofunctional monomer (A) and the polyfunctional (meth)acrylate (C), the content of the monofunctional monomer (A) is 10 to 75% by weight, the content of the polyfunctional (meth)acrylate (C) is 25 to 90% by weight, the content of the photopolymerization initiator (D) is 0.1 to 20% by weight, and the molecular weight between crosslinking points is 1,000 to 25,000; a cured product obtained by curing the active energy ray curable composition.

[0011] Effects of the Invention

[0012] The active energy ray-curable composition of the present invention exhibits the effect of providing a cured product having excellent flexibility and stretchability. Detailed Description of the Invention

[0013] The active energy ray-curable composition of the present invention is an active energy ray-curable composition containing a monofunctional monomer (A), a polyfunctional (meth)acrylate (C) having a number average molecular weight of 500 to 40,000, and a photopolymerization initiator (D).

[0014] It should be noted that in the present invention, “(meth)acrylate” means “methacrylate or acrylate”, “(meth)acrylic acid” means “methacrylic acid or acrylic acid”, and “(meth)acryloyl” means “methacryloyl or acryloyl”.

[0015] Hereinafter, the monofunctional monomer (A), the polyfunctional (meth)acrylate (C) having a number average molecular weight of 500 to 40,000, and the photopolymerization initiator (D), which are essential components of the active energy ray-curable composition of the present invention, will be described in turn.

[0016] The monofunctional monomer (A) contains a monofunctional monomer (A1) having a glass transition temperature of the homopolymer lower than 25°C and a monofunctional monomer (A2) having a glass transition temperature of the homopolymer of 25°C or higher.

[0017] The monofunctional monomer (A1) having a glass transition temperature of the homopolymer lower than 25°C is not particularly limited in chemical structure as long as the glass transition temperature of the homopolymer is lower than 25°C.

[0018] Here, the glass transition temperature of the homopolymer means the temperature at which the loss tangent (tanδ) shows a maximum value when measuring the dynamic viscoelasticity of the polymer obtained by homopolymerizing the monofunctional monomer by the following method.

[0019] <Preparation of Test Specimen>

[0020] (1) As a photoinitiator for free radical polymerization, 3% by weight of 1-hydroxycyclohexyl phenyl ketone [trade name “Irgacure184”, manufactured by IGM Resins B.V.] was added to the monofunctional monomer, and stirred until homogeneous to prepare a sample for test specimen production.

[0021] (2) Cut a silicone rubber sheet with a thickness of 1 mm [Product name: Silicone Rubber Sheet, manufactured by AS ONE Corporation] into a width of 10 mm × a length of 150 mm. Paste two obtained silicone rubber sheets at both ends of a glass plate [Product name: GLASS PLATE, manufactured by AS ONE Corporation, longitudinal 200 mm × transverse 200 mm × thickness 5 mm]. Place about 5 g of test pieces between the silicone rubber sheets to make a sample. Cover it with a PET film [Product name: Lumirror S, manufactured by Toray Industries, Inc.] so that air does not enter from above, and then cover it with a glass plate from above to make a laminate.

[0022] (3) Irradiate the laminate in (2) with a UV irradiation device (e.g., VPS / I600 manufactured by Fusion UV Systems Japan, lamp: D lamp) at an illuminance of 1500 mW / cm 2 (UV-A) for 1000 mJ / cm 2 of irradiation. Then turn over the laminate in (2) and irradiate it from the opposite side with 1000 mJ / cm 2 of irradiation to cure the composition.

[0023] (4) Cut the cured sample in (3) into a longitudinal width of 40 mm, a transverse width of 5 mm, and a thickness of 1 mm to make a test piece.

[0024] <Dynamic Viscoelasticity Measurement Method>

[0025] Use this test piece and measure the dynamic viscoelasticity under the following conditions with a dynamic viscoelasticity measurement device (e.g., Rheogel-E4000, manufactured by UBM Corporation).

[0026] Measurement mode: Temperature dependence, measurement temperature range: -80°C to 200°C, frequency: 10 Hz, heating rate: 4°C / minute, strain waveform: sine wave, measurement jig: tension

[0027] Take the temperature at which the ratio (tanδ) of the loss modulus E” to the storage modulus E’ of the obtained spectrum reaches the maximum as the glass transition temperature (Tg).

[0028] As the monofunctional monomer (A1) whose glass transition temperature as a homopolymer is lower than 25°C, it is preferably at least one selected from the group consisting of monofunctional (meth)acrylates (E) having a linear or branched alkyl group with 10 to 22 carbon atoms, monofunctional urethane (meth)acrylates (F), and other monofunctional (meth)acrylates (G).

[0029] As the monofunctional (meth)acrylate (E) having a linear or branched alkyl group with 10 to 22 carbon atoms, examples include decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, stearyl (meth)acrylate, isostearyl (meth)acrylate, behenyl (meth)acrylate, and the like. These (meth)acrylates can be easily produced by direct esterification or transesterification of (meth)acrylic acid, methyl (meth)acrylate, or the like with natural or synthetic alcohols. When using natural alcohols, the alkyl group becomes a linear alkyl group and the number of carbon atoms is an even number. When using synthetic alcohols, for example, when using Dobanol (manufactured by Mitsubishi Chemical Corporation), the alkyl group becomes a mixture of a linear alkyl group and a branched alkyl group, and the number of carbon atoms also becomes a mixture of odd and even numbers. When using Diadol (manufactured by Mitsubishi Chemical Corporation), the alkyl group becomes a mixture of a linear alkyl group and a branched alkyl group, and the number of carbon atoms is only an odd number.

[0030] In the present invention, these monofunctional (meth)acrylates (E) having a linear or branched alkyl group with 10 to 22 carbon atoms may be used alone or in combination of two or more.

[0031] Among these monofunctional (meth)acrylates (E) having a linear or branched alkyl group with 10 to 22 carbon atoms, lauryl (meth)acrylate, isodecyl (meth)acrylate, and isostearyl (meth)acrylate are preferred from the viewpoints of the elongation of the cured product, the strength of the cured product, and the adhesion to the substrate.

[0032] The monofunctional urethane (meth)acrylate (F) in the present invention refers to a monomer having one (meth)acryloyl group and at least one urethane group in the molecule. From the viewpoint of viscosity, a monomer having one (meth)acryloyl group and one urethane group is preferred.

[0033] As the monofunctional urethane (meth)acrylate (F), examples include reaction products of a monofunctional (meth)acrylate (a) having a hydroxyl group and an organic monoisocyanate compound (b).

[0034] As the monofunctional (meth)acrylate (a) having a hydroxyl group, examples include hydroxyalkyl (meth)acrylates ((2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 1,4-cyclohexanedimethanol monoacrylate, etc.)).

[0035] The monofunctional (meth)acrylate (a) having a hydroxyl group may be used alone or in combination of two or more.

[0036] Among these monofunctional (meth)acrylates (a) having a hydroxyl group, from the viewpoint of viscosity, 2-hydroxyethyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate are preferred.

[0037] Examples of the organic monoisocyanate compound (b) include aliphatic monoisocyanate compounds (b1), alicyclic monoisocyanate compounds (b2), and aromatic monoisocyanate compounds (b3).

[0038] Examples of the aliphatic monoisocyanate compound (b1) include methyl isocyanate, ethyl isocyanate, propyl isocyanate, isopropyl isocyanate, butyl isocyanate, hexyl isocyanate, octyl isocyanate, lauryl isocyanate, tetradecyl isocyanate, hexadecyl isocyanate, and octadecyl isocyanate.

[0039] Examples of the alicyclic monoisocyanate compound (b2) include cyclohexyl isocyanate.

[0040] Examples of the aromatic monoisocyanate compound (b3) include phenyl isocyanate and tolyl isocyanate.

[0041] The organic monoisocyanate compound (b) may be used alone as one kind, or two or more kinds may be used in combination.

[0042] Among these organic monoisocyanate compounds (b), from the viewpoints of the elongation and viscosity of the cured product, aliphatic monoisocyanate compounds (b1) and alicyclic monoisocyanate compounds (b2) are preferred, aliphatic monoisocyanate compounds (b1) are more preferred, and methyl isocyanate, ethyl isocyanate, propyl isocyanate, butyl isocyanate, and hexyl isocyanate are particularly preferred.

[0043] As the monofunctional urethane (meth)acrylate (F), a reaction product obtained by subjecting a monofunctional (meth)acrylate (a) having a hydroxyl group to a urethanization reaction with an organic monoisocyanate compound (b) by a known method can be used. Alternatively, commercially available products can also be used. Examples of commercially available products include Viscoat #216 (2-[(butylamino)carbonyl]oxyethyl acrylate: manufactured by Osaka Organic Chemical Industry Co., Ltd.), Etermer EM2080 (manufactured by Changxing Materials Industry Co., Ltd.), and Genomer 1122 (manufactured by RAHN Co., Ltd.).

[0044] As other monofunctional (meth)acrylates (G), examples thereof include methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, tert-butyl (meth)acrylate, hexyl (meth)acrylate, isoamyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, benzyl (meth)acrylate, phenoxyethyl (meth)acrylate, 2-ethylhexyl diglycol (meth)acrylate, 2-ethylhexyl carbitol (meth)acrylate, 2,2,2-trifluoroethyl (meth)acrylate, 1H,1H,2H,2H-perfluorodecyl (meth)acrylate, 4-butylphenyl (meth)acrylate, phenyl (meth)acrylate, 2,4,5-trimethylphenyl (meth)acrylate, phenoxymethyl (meth)acrylate, phenoxyethyl (meth)acrylate, trimethoxysilylpropyl (meth)acrylate, triethoxysilylpropyl (meth)acrylate, trimethylsilylpropyl (meth)acrylate, trifluoroethyl (meth)acrylate, perfluorooctylethyl (meth)acrylate, tetrahydrofurfuryl acrylate, 2-hydroxyethyl acrylate, methoxytriethylene glycol acrylate, etc.

[0045] In the present invention, these other monofunctional (meth)acrylates (G) may be used alone or in combination of two or more.

[0046] The monofunctional monomer (A2) whose homopolymer has a glass transition temperature of 25°C or higher is not particularly limited in chemical structure as long as the homopolymer has a glass transition temperature of 25°C or higher. As the monofunctional monomer (A2) whose homopolymer has a glass transition temperature of 25°C or higher, examples thereof include (meth)acrylates (H) having an alicyclic skeleton, monofunctional monomers (I) having a nitrogen atom in the molecule, and other monofunctional (meth)acrylates (J). From the viewpoint of curability, monofunctional monomers (I) having a nitrogen atom in the molecule are preferred.

[0047] As the (meth)acrylates (H) having an alicyclic skeleton, examples thereof include isobornyl (meth)acrylate, cyclohexyl (meth)acrylate, tert-butylcyclohexyl (meth)acrylate, 1-ethylcyclohexyl (meth)acrylate, and adamantyl (meth)acrylate.

[0048] In the present invention, these (meth)acrylates (H) having an alicyclic skeleton may be used alone or in combination of two or more.

[0049] Among these (meth)acrylates (H) having an alicyclic skeleton, from the viewpoints of the elongation of the cured product and the strength of the cured product, isobornyl (meth)acrylate, tert-butylcyclohexyl (meth)acrylate, trimethylcyclohexyl (meth)acrylate, and 1-ethylcyclohexyl (meth)acrylate are preferred.

[0050] As the monofunctional monomer (I) having a nitrogen atom in the molecule, N-substituted vinyl monomers, N-substituted (meth)acrylamides, etc. can be mentioned. From the viewpoint of curability, N-substituted (meth)acrylamides are preferred.

[0051] As the N-substituted vinyl monomer, N-vinylpyrrolidone, N-vinylcarbazole, N-vinylcaprolactam, N-vinylimidazole, vinylmethyl oxazolidinone, etc. can be mentioned.

[0052] In the present invention, the N-substituted (meth)acrylamide means a substance obtained by substituting one or two hydrogen atoms of the amino group of (meth)acrylamide with a substituent such as a hydrocarbon group. As the N-substituted (meth)acrylamide, a chain amide (I1) having an N-(meth)acryloyl group, a cyclic amide (I2) having an N-(meth)acryloyl group, diacetone acrylamide, etc. can be mentioned.

[0053] As the chain amide (I1) having an N-(meth)acryloyl group, N-alkyl (meth)acrylamide (I11), N,N-dialkyl (meth)acrylamide (I12), N-hydroxyalkyl (meth)acrylamide (I13), N-alkoxyalkyl (meth)acrylamide (I14), and N-alkyl-N-alkoxy (meth)acrylamide (I15), etc. can be mentioned.

[0054] As the N-alkyl (meth)acrylamide (I11), N-methyl (meth)acrylamide, N-ethyl (meth)acrylamide, N-propyl (meth)acrylamide, N-isopropyl (meth)acrylamide, N-dodecyl (meth)acrylamide, N-octadecyl (meth)acrylamide, etc. can be mentioned.

[0055] As the N,N-dialkyl (meth)acrylamide (I12), N,N-dimethyl (meth)acrylamide, N,N-diethyl (meth)acrylamide, N,N-dipropyl (meth)acrylamide, N,N-diisopropyl (meth)acrylamide, N,N-dibutyl (meth)acrylamide, N,N-diisobutyl (meth)acrylamide, N,N-di-tert-butyl (meth)acrylamide, N,N-diheptyl (meth)acrylamide, N,N-dioctyl (meth)acrylamide, N,N-di-tert-octyl (meth)acrylamide, N,N-di(dodecyl) (meth)acrylamide, and N,N-di(octadecyl) (meth)acrylamide, etc. can be mentioned. The two alkyl groups of the N,N-dialkyl (meth)acrylamide (I12) may be the same or different. From the viewpoint of curability, the number of carbon atoms of the alkyl group is preferably 1 to 20, more preferably 1 to 8, and particularly preferably 1 to 4.

[0056] Examples of the N-hydroxyalkyl(meth)acrylamide (I13) include N-hydroxymethyl(meth)acrylamide, N-hydroxyethyl(meth)acrylamide, and N-(3-hydroxypropyl)(meth)acrylamide. From the viewpoint of curability, the number of carbon atoms of the alkyl group in the N-hydroxyalkyl(meth)acrylamide (I13) is preferably 1 to 20, more preferably 1 to 8, and particularly preferably 1 to 4.

[0057] Examples of the N-alkoxyalkyl(meth)acrylamide (I14) include N-methoxymethyl(meth)acrylamide, N-ethoxymethyl(meth)acrylamide, N-propoxymethyl(meth)acrylamide, N-butoxymethyl(meth)acrylamide, N-methoxyethyl(meth)acrylamide, N-ethoxyethyl(meth)acrylamide, N-butoxyethyl(meth)acrylamide, N-methoxypropyl(meth)acrylamide, N-ethoxypropyl(meth)acrylamide, N-methoxybutyl(meth)acrylamide, and N-ethoxybutyl(meth)acrylamide. From the viewpoint of curability, the number of carbon atoms of the alkoxyalkyl group in the N-alkoxyalkyl(meth)acrylamide (I14) is preferably 2 to 20, more preferably 2 to 8, and particularly preferably 2 to 6. From the viewpoint of curability, the number of carbon atoms of the alkyl group of the alkoxyalkyl is preferably 1 to 4, more preferably 1 to 3, and particularly preferably 1 to 2.

[0058] Examples of the N-alkyl-N-alkoxy(meth)acrylamide (I15) include N-methyl-N-methoxy(meth)acrylamide, N-methyl-N-ethoxy(meth)acrylamide, N-methyl-N-propoxy(meth)acrylamide, N-methyl-N-butoxy(meth)acrylamide, N-ethyl-N-methoxy(meth)acrylamide, N-ethyl-N-ethoxy(meth)acrylamide, N-ethyl-N-butoxy(meth)acrylamide, N-propyl-N-methoxy(meth)acrylamide, N-propyl-N-ethoxy(meth)acrylamide, N-butyl-N-methoxy(meth)acrylamide, and N-butyl-N-ethoxy(meth)acrylamide.

[0059] Examples of the cyclic amide having an N-(meth)acryloyl group (I2) include N-(meth)acryloylmorpholine, N-(meth)acryloylthiomorpholine, N-(meth)acryloylpiperidine, N-(meth)acryloylpyrrolidine, and N-(meth)acryloylpiperidine. From the viewpoint of curability, the number of carbon atoms of the cyclic amide having an N-(meth)acryloyl group is preferably 7 to 20, more preferably 7 to 18, and particularly preferably 7 to 16.

[0060] In the present invention, these N-substituted (meth)acrylamides can be used alone or in combination of two or more.

[0061] Among these N-substituted (meth)acrylamides, from the viewpoints of viscosity, curability, and elongation of the cured product, N,N-dialkyl (meth)acrylamides (I12), N-alkoxyalkyl (meth)acrylamides (I14), and cyclic amides having an N-(meth)acryloyl group (I2) are preferred, N,N-dialkyl (meth)acrylamides (I12) and cyclic amides having an N-(meth)acryloyl group (I2) are more preferred, and N,N-dimethyl (meth)acrylamide, N,N-diethyl (meth)acrylamide, and N-(meth)acryloylmorpholine are particularly preferred.

[0062] As other monofunctional (meth)acrylates (J), cyclic trimethylolpropane formal (meth)acrylate, 2-phenoxyethyl acrylate, etc. can be cited.

[0063] As the polyfunctional (meth)acrylates (C) having a number average molecular weight of 500 to 40,000, bifunctional (meth)acrylates having a number average molecular weight of 500 to 40,000 are preferred, and the bifunctional (meth)acrylates (K) represented by the general formula (1) or other bifunctional (meth)acrylates (L) can be cited.

[0064] As the bifunctional (meth)acrylate (K) represented by the general formula (1), it is the following substance.

[0065] CH2=CXCO-O-(R-O) n -COCX=CH2(1)

[0066] [In the general formula (1), n is an integer of 2 or more and 15 or less, R is an alkylene group having 2 or more and 6 or less carbon atoms (wherein when there are a plurality of Rs in one molecule, each R is independently an alkylene group having 2 or more and 6 or less carbon atoms), and each X is independently a hydrogen atom or a methyl group.]

[0067] In the general formula (1), R represents an alkylene group having 2 or more and 6 or less carbon atoms. Specifically, ethylene, 1,2-propylene, 1,3-propylene, 1,2-butylene, 1,3-butylene, 1,4-butylene, etc. can be cited.

[0068] From the viewpoint of the hardness of the cured product, R is preferably 2 to 3 carbon atoms, and more preferably ethylene and 1,2-propylene.

[0069] n is an integer of 2 or more and 15 or less. From the viewpoints of low gas release property and bend resistance, it is preferably an integer of 7 or more and 15 or less.

[0070] Examples of the bifunctional (meth)acrylate (K) represented by the general formula (1) include polyethylene glycol (n = 9) di(meth)acrylate, polyethylene glycol (n = 14) di(meth)acrylate, polypropylene glycol (n = 7) di(meth)acrylate, and polypropylene glycol (n = 12) di(meth)acrylate. Note that n represents the number of repetitions of the alkyleneoxy group. The same applies hereinafter.

[0071] These bifunctional (meth)acrylates (K) can be used alone or in combination of two or more.

[0072] Among them, from the viewpoint of the hardness of the cured product, bifunctional acrylate is preferred, and polyethylene glycol (n = 9) diacrylate, polyethylene glycol (n = 14) diacrylate, polypropylene glycol (n = 7) diacrylate, and polypropylene glycol (n = 12) diacrylate are particularly preferred. Polypropylene glycol (n = 7) diacrylate and polypropylene glycol (n = 12) diacrylate are most preferred.

[0073] Examples of other bifunctional (meth)acrylates (L) include di(meth)acrylates (L1) of 4 - 25 molar addition products of alkylene oxides (with 2 - 4 carbon atoms in the alkylene group) of diphenol compounds, diesters of 1 - 15 molar addition products of alkylene oxides (with 2 - 4 carbon atoms in the alkylene group) of dihydric alcohols having 2 - 30 carbon atoms and (meth)acrylic acid, diesters of diglycidyl ethers and (meth)acrylic acid, di(meth)acrylates of ethylene oxide addition products of fluorene, polysiloxane diacrylates (L2), urethane diacrylates (L3), etc.

[0074] Examples of the di(meth)acrylate (L1) of 4 - 25 molar addition products of alkylene oxides (with 2 - 4 carbon atoms in the alkylene group) of diphenol compounds include di(meth)acrylates of alkylene oxide addition products of diphenol compounds [monocyclic phenols (catechol, resorcinol, hydroquinone, etc.), condensed polycyclic phenols (dihydroxynaphthalene, etc.), bisphenol compounds (bisphenol A, bisphenol F, bisphenol S, etc.)]. For example, di(meth)acrylates of ethylene oxide addition products of catechol (hereinafter, ethylene oxide may be abbreviated as EO), di(meth)acrylates of 1,2 - or 1,3 - propylene oxide addition products of dihydroxynaphthalene (hereinafter, 1,2 - or 1,3 - propylene oxide may be abbreviated as PO), and di(meth)acrylates of EO addition products of bisphenol A.

[0075] Examples of the polysiloxane diacrylate (L2) include EBECRYL350, EBECRYL1360, etc.

[0076] The urethane diacrylate (L3) is a urethane (meth)acrylate containing a polyol (m), a polyisocyanate (n), and an active hydrogen - containing (meth)acrylate (c) as constituent raw materials.

[0077] As the polyol (m), examples thereof include linear aliphatic polyols (m1) having 1 to 20 carbon atoms, alicyclic polyols (m2) having 6 to 20 carbon atoms, aromatic polyols (m3) having 6 to 20 carbon atoms, and their alkylene oxide [ethylene oxide (EO), 1,2- or 1,3-propylene oxide (PO), 1,2-, 1,3-, 1,4- or 2,3-butylene oxide, etc.] adducts, etc.

[0078] As the linear aliphatic polyol (m1), examples thereof include linear aliphatic diols having 1 to 20 carbon atoms (ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, etc.), branched aliphatic diols (1,2-propanediol, 1,2-, 1,3- or 2,3-butanediol, 2-methyl-1,4-butanediol, neopentyl glycol, 2,2-diethyl-1,3-propanediol, 2-methyl-1,5-pentanediol, 3-methyl-1,5-pentanediol, etc.), and linear aliphatic polyols having 3 to 8 hydroxyl groups (pentaerythritol, sorbitol, mannitol, sorbitan, diglycerol, dipentaerythritol, etc.).

[0079] As the alicyclic polyol (m2) having 6 to 20 carbon atoms, examples thereof include 1,2-cyclohexanediol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanediol, 1,3-cyclopentanediol, 1,4-cycloheptanediol, 1,4-bis(hydroxymethyl)cyclohexane, 2,2-bis(4-hydroxycyclohexyl)propane, 1,3,5-cyclohexanetriol, etc.

[0080] As the aromatic polyol (m3) having 6 to 20 carbon atoms, examples thereof include resorcinol, hydroquinone, naphthalenediol, and bisphenols (bisphenol A, bisphenol F, bisphenol S, etc.).

[0081] When using the alkylene oxide adduct of the above linear aliphatic polyol (m1), alicyclic polyol (m2) or aromatic polyol (m3) as the polyol (m), from the viewpoint of the elongation of the cured product, the addition molar number of the alkylene oxide is preferably 1 to 50 moles, more preferably 4 to 30 moles.

[0082] Among these polyols (m), from the viewpoint of the elongation of the cured product, the alkylene oxide adduct of the above linear aliphatic polyol (m1) is preferred, the 1,4-butylene oxide adduct of the aliphatic polyol (m1) is more preferred, and poly-1,4-butylene oxide (polytetramethylene glycol) is particularly preferred.

[0083] The polyol (m) may be used alone or in combination of two or more.

[0084] As the polyisocyanate (n), examples thereof include linear aliphatic polyisocyanates (n1) having 4 to 20 carbon atoms, alicyclic polyisocyanates (n2) having 6 to 22 carbon atoms, and aromatic polyisocyanates (n3) having 8 to 22 carbon atoms, etc.

[0085] As the linear aliphatic polyisocyanate (n1) having 4 to 20 carbon atoms, examples thereof include ethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), dodecamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, and lysine diisocyanate, etc.

[0086] As the alicyclic polyisocyanate (n2) having 6 to 22 carbon atoms, examples thereof include cyclohexane-1,3-diylbis(methylene diisocyanate), isophorone diisocyanate (IPDI), 2,4- or 2,6-methylcyclohexane diisocyanate (hydrogenated TDI), dicyclohexylmethane-4,4'-diisocyanate (hydrogenated MDI, hereinafter sometimes referred to as MDIH), cyclohexylidene diisocyanate, methylcyclohexylidene diisocyanate, bis(2-isocyanatoethyl)-4-cyclohexyl-1,2-dicarboxylate, 2,5- or 2,6-norbornane diisocyanate, and dimer acid diisocyanate, etc.

[0087] As the aromatic polyisocyanate (n3) having 8 to 22 carbon atoms, examples thereof include 1,3- or 1,4-phenylene diisocyanate, 2,4- or 2,6-toluene diisocyanate (TDI), 4,4'- or 2,4'-diphenylmethane diisocyanate (MDI), m- or p-isocyanatobenzenesulfonyl isocyanate, 4,4'-diisocyanatobiphenyl, 3,3'-dimethyl-4,4'-diisocyanatobiphenyl, 3,3'-dimethyl-4,4'-diisocyanatodiphenylmethane, 1,5-naphthalene diisocyanate, m- or p-isocyanatobenzenesulfonyl isocyanate, m- or p-xylylene diisocyanate (XDI), and α,α,α',α'-tetramethylxylylene diisocyanate (TMXDI), etc.

[0088] Among these polyisocyanates (n), from the viewpoints of the elongation rate and light resistance of the cured product, alicyclic polyisocyanates (n2) having 6 to 22 carbon atoms and aromatic polyisocyanates (n3) having 8 to 22 carbon atoms are preferred, alicyclic polyisocyanates having 6 to 20 carbon atoms and aromatic polyisocyanates having 8 to 20 carbon atoms are more preferred, cyclohexane-1,3-diylbis(methylene diisocyanate), IPDI, XDI, TMXDI, MDI, and TDI are particularly preferred, and IPDI is most preferred.

[0089] The polyisocyanate (n) may be used alone as one kind, or two or more kinds may be used in combination.

[0090] Examples of the (meth)acrylate (c) having an active hydrogen group include a hydroxy group-containing (meth)acrylate (c1), an amino group-containing (meth)acrylate (c2), a carboxyl group-containing (meth)acrylate (c3), and the like. Among them, a hydroxy group-containing (meth)acrylate is preferred.

[0091] Examples of the hydroxy group-containing (meth)acrylate (c1) include a hydroxyalkyl (meth)acrylate (c11) and a polyalkylene glycol mono(meth)acrylate (c12).

[0092] Examples of the hydroxyalkyl (meth)acrylate (c11) preferably include a hydroxyalkyl (meth)acrylate having 4 to 20 carbon atoms. Specifically, examples include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and 3-hydroxypropyl (meth)acrylate.

[0093] Examples of the polyalkylene glycol mono(meth)acrylate (c12) include polyethylene glycol mono(meth)acrylate and polypropylene glycol mono(meth)acrylate.

[0094] Examples of the amino group-containing (meth)acrylate (c2) include a monoalkyl (having 1 to 4 carbon atoms) aminoalkyl (having 2 to 6 carbon atoms) (meth)acrylate {aminoethyl (meth)acrylate, aminopropyl (meth)acrylate, methylaminoethyl (meth)acrylate, ethylaminoethyl (meth)acrylate, butylaminoethyl (meth)acrylate, or methylaminopropyl (meth)acrylate} and a dialkyl (having 1 to 4 carbon atoms) aminoalkyl (having 2 to 6 carbon atoms) (meth)acrylate {dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, dibutylaminoethyl (meth)acrylate, etc.}.

[0095] Examples of the carboxyl group-containing (meth)acrylate (c3) include 2-(meth)acryloyloxyethyl succinic acid, 2-(meth)acryloyloxyethyl phthalic acid, and 2-(meth)acryloyloxyethyl hexahydrophthalic acid.

[0096] Among the (meth)acrylates (c) having an active hydrogen group, from the viewpoints of the reactivity of the urethanization reaction and the elongation of the cured product, a hydroxy group-containing (meth)acrylate (c1) is preferred, a hydroxy group-containing monofunctional (meth)acrylate is more preferred, a hydroxyalkyl (meth)acrylate (c11) is particularly preferred, and 2-hydroxyethyl (meth)acrylate is most preferred.

[0097] The (meth)acrylate (c) having an active hydrogen group may be used alone or in combination of two or more.

[0098] The above urethane diacrylate (L3) can be used alone as one kind, or two or more kinds can be used in combination.

[0099] Regarding the polyol (m), polyisocyanate (n), and active hydrogen group-containing (meth)acrylate (c) that are constituent raw materials of the urethane diacrylate (L3), the molar ratio of the isocyanate groups possessed by the polyisocyanate (n) to the active hydrogen groups possessed by the polyol (m) and the active hydrogen group-containing (meth)acrylate (c) [(isocyanate groups possessed by (n) / total of active hydrogen groups possessed by (m) and active hydrogen groups possessed by (c))] is not particularly limited. From the viewpoint of storage stability, it is preferably 1 / 0.5 to 1 / 10, more preferably 1 / 0.7 to 1 / 5, and particularly preferably 1 / 1 to 1 / 2.

[0100] The urethane diacrylate (L3) in the present invention can be produced by reacting a polyol (m), a polyisocyanate (n), and an active hydrogen group-containing (meth)acrylate (c) by a known method.

[0101] Among them, it is preferably produced as follows: a urethane prepolymer having two or more isocyanate groups is produced by a polyaddition reaction of a polyol (m) and a polyisocyanate (n), and then an addition reaction of an active hydrogen group-containing (meth)acrylate (c) is carried out.

[0102] In the above polyaddition reaction and addition reaction, a urethanization catalyst can be used.

[0103] Examples of the urethanization catalyst include metal compounds (such as organic bismuth compounds, organic tin compounds, and organic titanium compounds) and quaternary ammonium salts.

[0104] The polyfunctional (meth)acrylate (C) having a number average molecular weight of 500 to 40,000 can be a (meth)acrylate having three or more functional groups, and examples thereof include urethane tetraacrylate.

[0105] As the photopolymerization initiator (D), there is no limitation as long as it is a substance that generates free radicals, ions, etc. by irradiation with active energy rays to cause the polymerization reaction of monomers, and a photopolymerization initiator that generates free radicals by irradiation with active energy rays can be preferably used.

[0106] Examples of the preferred photopolymerization initiator (D) include acylphosphine oxide-based compounds (D1), α-hydroxyalkylbenzophenone-based compounds (D2), α-aminoalkylbenzophenone-based compounds (D3), ketal-based compounds (D4), benzoylformate-based compounds (D5), thioxanthone-based compounds (D6), benzophenone-based compounds (D7), and oxime ester-based compounds (D8).

[0107] As the acylphosphine oxide compound (D1), examples thereof include bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, and ethyl 2,4,6-trimethylbenzoyl phenylphosphonate, etc.

[0108] As the α-hydroxyalkyl phenyl ketone compound (D2), examples thereof include 1-hydroxycyclohexyl phenyl ketone and 2-hydroxy-2-methyl-1-phenylpropan-1-one, etc.

[0109] As the α-aminoalkyl phenyl ketone compound (D3), examples thereof include 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]butan-1-one, and 2-benzyl-2-(dimethylamino)-1-[4-(4-morpholinyl)phenyl]butan-1-one, etc.

[0110] As the ketal compound (D4), examples thereof include benzil dimethyl ketal, etc.

[0111] As the benzoylformate compound (D5), examples thereof include methyl benzoylformate, etc.

[0112] As the thioxanthone compound (D6), examples thereof include 2,4-diethylthioxanthone, 2-isopropylthioxanthone, and 2-chlorothioxanthone, etc.

[0113] As the benzophenone compound (D7), examples thereof include benzophenone, 4-benzoyl-4'-methyldiphenyl sulfide, and 4,4'-bis(dimethylamino)benzophenone, etc.

[0114] As the oxime ester compound (D8), examples thereof include 1-[4-(phenylthio)phenyl]-1,2-octanedione 2-(O-benzoyl oxime) and 1-[6-(2-methylbenzoyl)-9-ethyl-9H-carbazol-3-yl]ethanone-1-(O-acetyl oxime), etc.

[0115] In the present invention, these photoinitiators (D) can be used alone or in combination of two or more.

[0116] Among these photoinitiators (D), from the viewpoints of curability and transmittance of the cured product, the acylphosphine oxide compound (D1) and the α-hydroxyalkyl phenyl ketone compound (D2) are preferred, the acylphosphine oxide compound (D1) is more preferred, and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide and 2,4,6-trimethylbenzoyldiphenylphosphine oxide are particularly preferred.

[0117] The content of the monofunctional monomer (A) in the present invention is 10 to 75% by weight based on the total weight of the monofunctional monomer (A) and the polyfunctional (meth)acrylate (C). When the content of the monofunctional monomer (A) is less than 10% by weight, the elongation of the cured product is insufficient, and when it exceeds 75% by weight, the flexibility of the cured product is insufficient.

[0118] From the viewpoints of curability and flexibility, the content of the monofunctional monomer (A1) having a glass transition temperature of less than 25 °C of the homopolymer in the present invention is preferably 5 to 30% by weight, more preferably 5 to 25% by weight, based on the total content of the monofunctional monomer (A) and the polyfunctional (meth)acrylate (C).

[0119] From the viewpoints of curability and flexibility, the content of the monofunctional monomer (A2) having a glass transition temperature of 25 °C or more of the homopolymer is preferably 5 to 70% by weight based on the total weight of the monofunctional monomer (A) and the polyfunctional (meth)acrylate (C).

[0120] The content of the polyfunctional (meth)acrylate (C) in the present invention is 25 to 90% by weight based on the total weight of the monofunctional monomer (A) and the polyfunctional (meth)acrylate (C). When the content of the polyfunctional (meth)acrylate (C) is less than 25% by weight, the flexibility of the cured product is insufficient, and when it exceeds 90% by weight, the elongation is insufficient.

[0121] The content of the photopolymerization initiator (D) in the present invention is 0.1 to 20% by weight, preferably 2 to 20% by weight, more preferably 2 to 18% by weight, and further preferably 5 to 15% by weight, based on the total weight of the monofunctional monomer (A) and the polyfunctional (meth)acrylate (C). If the content of the photopolymerization initiator (D) is less than 0.1% by weight, the curability becomes insufficient, and if it exceeds 20% by weight, the transmittance of the cured product becomes insufficient.

[0122] The molecular weight between crosslinks in the present invention is 1000 to 25000. The molecular weight between crosslinks is represented by [Mc] (g / mol), and from the viewpoints of flexibility and resilience, it is preferably 1200 to 20000 g / mol, more preferably 1300 to 15000. The molecular weight between crosslinks [Mc] (g / mol) can be calculated by the following calculation formula (1).

[0123] [Mc] = 1 / {a0×(1 / Mc0)+a1×(1 / Mc1)+……+a i ×(1 / Mc i )+……+a n ×(1 / Mc n )}(1)

[0124] In the above calculation formula (1), a0, a1, …… ai , ……a n represents the weight % of each component of the monomers that make up (hereinafter simply referred to as each component).

[0125] In addition, Mc0, Mc1, ……Mc i , ……Mc n represents the molecular weight between crosslinking points of each component.

[0126] In addition, [Mc i (g / mol) can be calculated by the following calculation formula (2).

[0127] [Mc i = Mn / {2×(n - 1)}(2)

[0128] In the above calculation formula (2), Mn represents the number average molecular weight (g / mol) of each component, and n represents the number of (meth)acryloyl groups that each component has (n is 2 or more).

[0129] The active energy ray curable composition of the present invention may contain other monomers (M) other than the monofunctional monomer (A) and the polyfunctional (meth)acrylate (C) having a number average molecular weight of 500 to 40000 within the range that does not hinder the effects of the present invention.

[0130] As other monomers (M), examples include difunctional or higher (meth)acrylates other than the polyfunctional (meth)acrylate (C) [for example, difunctional (meth)acrylate (N) (excluding substances equivalent to the polyfunctional (meth)acrylate (C)), trifunctional or higher (meth)acrylate (O), and (meth)acrylate (P) having a phosphate group, etc.].

[0131] It should be noted that when a monomer having a cationic polymerizable group such as a vinyl ether group and N-vinyl is used in the present invention, the storage stability of the active energy ray curable composition may become insufficient, and therefore it is preferably not used.

[0132] Examples of the bifunctional (meth)acrylate (N) include polyalkylene glycol (alkylene having 2 to 4 carbon atoms) di(meth)acrylate (N1), di(meth)acrylate (N2) of an alkylene oxide (alkylene having 2 to 4 carbon atoms) adduct of a dihydric phenol compound, a diester of an alkylene oxide (alkylene having 2 to 4 carbon atoms) adduct of a polyhydric (preferably 2- to 8-valent) alcohol having 2 to 30 carbon atoms and (meth)acrylic acid, a diester of a diglycidyl ether and (meth)acrylic acid, and di(meth)acrylate of an ethylene oxide adduct of fluorene, cyclohexanemethanol di(meth)acrylate, ethoxylated cyclohexanemethanol di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, and 1,3-adamantanediol di(meth)acrylate, etc.

[0133] In addition, examples of the polyfunctional (meth)acrylate having a number average molecular weight of less than 500 include 1,9-nonanediol di(meth)acrylate, etc.

[0134] In the present invention, these bifunctional (meth)acrylates (N) can be used alone or in combination of two or more.

[0135] Examples of the trifunctional or higher (meth)acrylate (O) include trifunctional (meth)acrylate monomers and tetrafunctional or higher (meth)acrylate monomers, etc.

[0136] Examples of the trifunctional (meth)acrylate monomer include trimethylolethane tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, an alkylene oxide (alkylene having 3 to 4 carbon atoms) modified trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol tri(meth)acrylate, trimethylolpropane tris((meth)acryloyloxypropyl) ether, sorbitol tri(meth)acrylate, a tri(meth)acrylate of a 1- to 30-mole addition product of an alkylene oxide (alkylene having 3 to 4 carbon atoms) to pentaerythritol, and ethoxylated glycerol tri(meth)acrylate, etc.

[0137] Examples of the tetrafunctional or higher (meth)acrylate monomer include pentaerythritol tetra(meth)acrylate, sorbitol tetra(meth)acrylate, bis(trimethylolpropane) tetra(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol tetra(meth)acrylate propionate, a tetra(meth)acrylate of a 1- to 11-mole addition product of an alkylene oxide (alkylene having 3 to 4 carbon atoms) to pentaerythritol, sorbitol penta(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, sorbitol hexa(meth)acrylate, and a caprolactone-modified dipentaerythritol hexa(meth)acrylate, etc.

[0138] In the present invention, these (meth)acrylates (O) having three or more functional groups may be used alone, or two or more thereof may be used in combination.

[0139] As the (meth)acrylate (P) having a phosphate group, there is no limitation as long as it is a phosphate ester having a (meth)acryloyl group, and examples thereof include (meth)acrylates having 1 to 3 functional groups of (meth)acryloyl group. Commercially available products can be used. As commercially available products, examples include 2-methacryloyloxyethyl acid phosphate (manufactured by Uni-Chemical Co., Ltd., Phosmer M), acid phosphyloxy polyethylene glycol monomethacrylate (manufactured by Uni-Chemical Co., Ltd., Phosmer PE), acid phosphyloxy polypropylene glycol monomethacrylate (manufactured by Uni-Chemical Co., Ltd., Phosmer PP), 2-acryloyloxyethyl acid phosphate (manufactured by Kyoeisha Chemical Co., Ltd., Light Acrylate P-1A(N)), 2-methacryloyloxyethyl acid phosphate (manufactured by Kyoeisha Chemical Co., Ltd., Light Ester P-1M), bis(2-methacryloyloxyethyl) acid phosphate (manufactured by Kyoeisha Chemical Co., Ltd., Light Ester P-2M), bis(2-methacryloyloxyethyl) acid phosphate (manufactured by Nippon Kayaku Co., Ltd., KAYAMER PM-2), and reaction product of 6-caprolactone addition polymer of 2-hydroxyethyl methacrylate and phosphoric anhydride (manufactured by Nippon Kayaku Co., Ltd., KAYAMER PM-21), etc.

[0140] In the present invention, these (meth)acrylates (P) having a phosphate group may be used alone, or two or more thereof may be used in combination.

[0141] Among the (meth)acrylates (P) having a phosphate group, from the viewpoint of metal adhesion, (meth)acrylates having a phosphate group with 1 to 2 functional groups of (meth)acryloyl group are preferred, and 2-(meth)acryloyloxyethyl acid phosphate, bis{2-(meth)acryloyloxyethyl} acid phosphate, and reaction product of 6-caprolactone addition polymer of 2-hydroxyethyl methacrylate and phosphoric anhydride are more preferred.

[0142] From the viewpoints of flexibility and adhesion, the content of other monomers (M) is preferably 0 to 20% by weight, more preferably 0 to 10% by weight, based on the total weight of the monofunctional monomer (A) and the polyfunctional (meth)acrylate (C).

[0143] From the viewpoint of elongation, the total content of the polyfunctional (meth)acrylate (C) and the polyfunctional (meth)acrylate having two or more functional groups other than the polyfunctional (meth)acrylate (C) is preferably 50% by weight or less based on the total weight of the monofunctional monomer (A) and the polyfunctional (meth)acrylate (C).

[0144] In the active energy ray-curable composition of the present invention, various additives can be contained as needed within a range that does not impair the effects of the present invention.

[0145] Examples of the additives include a leveling agent, a charge control agent, a light stabilizer, an ultraviolet absorber, a surface treatment agent, an antioxidant, an anti-aging agent, a crosslinking promoter, a plasticizer, a preservative, a pH adjuster, an antifoaming agent, and a humectant.

[0146] The method for producing the active energy ray-curable composition of the present invention is not particularly limited. For example, it can be produced by stirring and mixing the above-mentioned respective components in a suitable container such as a glass beaker, a tank, or a plastic cup using a stirring rod, a spatula, etc., or by uniformly mixing using a known mixing device (a method using a mechanical stirrer and a magnetic stirrer, a mixing device equipped with stirring blades such as a paddle type, a dissolver, a ball mill, and a planetary mixer, etc.).

[0147] It should be noted that the active energy ray-curable composition of the present invention is preferably in a liquid state at room temperature, and its viscosity can be measured using an E-type viscometer [such as "VISCOMETER TV-25L" manufactured by Toki Sangyo Co., Ltd.] and a B-type viscometer.

[0148] In order to obtain a cured product of the active energy ray-curable composition, the active energy ray-curable composition is coated on a substrate by a known method and then irradiated with active energy rays to cure it. Examples of the active energy rays in the present invention include ultraviolet rays and electron beams.

[0149] The active energy rays used in the curing of the active energy ray-curable composition of the present invention can be adjusted according to the selection of the photopolymerization initiator. In the case of using the above-mentioned photopolymerization initiator (D), photocuring can be carried out by irradiation with active energy rays having a wavelength of 200 to 700 nm, and curing is preferably carried out by irradiation with light (ultraviolet rays) having a wavelength of 200 to 400 nm.

[0150] As a light source that emits ultraviolet rays, in addition to high-pressure mercury lamps, ultra-high-pressure mercury lamps, metal halide lamps, high-power metal halide lamps, etc. (Latest Trends in UV·EB Curing Technology, edited by RadTech Research Group, published by CMC, page 138, 2006) and LEDs can also be used. Among them, compared with other light sources, LEDs consume less power, produce less ozone, have a lower operating cost, and a smaller environmental load. When curing with an LED light source, an LED light source ultraviolet irradiation device [for example, LED light source ultraviolet irradiation device "FJ100 150×20 365, phoseon", manufactured by TECHNOLOGY Co., Ltd.] can be used.

[0151] From the viewpoints of curability and flexibility of the cured product, the irradiation amount of ultraviolet rays when curing the active energy ray curable composition of the present invention is preferably 10 to 10,000 mJ / cm 2 , and more preferably 50 to 5,000 mJ / cm 2 .

[0152] When irradiating the above-mentioned electron beam, a known electron beam irradiation device can be used. From the viewpoints of curability and suppression of deterioration of the cured product, the irradiation amount of the electron beam is preferably 1 to 10 Mrad.

[0153] The material coated with the active energy ray curable composition of the present invention can be appropriately selected according to the use, etc., and organic materials such as plastics, and inorganic materials such as metals and glass can be used.

[0154] Examples of the metal include steel, hot-dip galvanized steel, electro-galvanized steel, tinplate, tin-free steel, various other plated or alloy-plated steels, stainless steel, aluminum, gold, platinum, silver, and copper. In addition, various surface treatments such as phosphate treatment, chromate treatment, organic phosphate treatment, organic chromate treatment, and heavy metal replacement treatment can also be carried out.

[0155] Examples of the plastic material include polyester resins {such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN)}, acrylic resins (such as methyl methacrylate copolymer), triacetyl cellulose, acrylonitrile-butadiene-styrene copolymer (ABS) resin, styrene resin, polysulfone resin, polyethersulfone resin, polycarbonate resin, vinyl chloride resin, polymethacrylimide resin, and polyolefin resins (such as polyethylene, polypropylene, and cycloolefin polymer), etc.

[0156] Examples of the inorganic material include glass and ceramics.

[0157] Among these materials, the active energy ray curable composition of the present invention has particularly excellent adhesion to metals.

[0158] As a method for coating the active energy ray curable composition of the present invention on a substrate, known coating methods such as spin coating, roll coating, and spray coating, as well as known printing methods such as lithography, carton printing, metal printing, offset printing, screen printing, and gravure printing can be applied. In addition, since the composition of the present invention has a low viscosity at room temperature, it can also be applied to coating by an inkjet method (inkjet printing) that continuously ejects fine droplets.

[0159] Inkjet printing can perform precise and high-speed printing with relatively simple equipment, and thus is suitable for manufacturing display components such as liquid crystal displays and organic EL displays, as well as other electronic components and optical components.

[0160] The active energy ray curable composition of the present invention has a low viscosity, and the cured product of the active energy ray curable composition has excellent elongation and elastic modulus, and thus is useful as a material for various electronic components and optical components represented by display components. In particular, it is suitable for bonding and sealing uses of display components, electronic components such as image sensors, and semiconductor packages. In addition, it can also be widely used for various coating, ink (such as UV printing ink and UV inkjet printing ink), and coating uses.

[0161] <Others>

[0162] The present invention may also include the following configurations.

[0163] <1>

[0164] An active energy ray curable composition containing a monofunctional monomer (A), a polyfunctional (meth)acrylate (C) having a number average molecular weight of 500 to 40,000, and a photoinitiator (D), wherein the monofunctional monomer (A) contains a monofunctional monomer (A1) having a glass transition temperature of the homopolymer below 25°C and a monofunctional monomer (A2) having a glass transition temperature of the homopolymer of 25°C or higher. Based on the total weight of the monofunctional monomer (A) and the polyfunctional (meth)acrylate (C), the content of the monofunctional monomer (A) is 10 to 75% by weight, the content of the polyfunctional (meth)acrylate (C) is 25 to 90% by weight, the content of the photoinitiator (D) is 0.1 to 20% by weight, and the molecular weight between crosslinking points is 1000 to 25,000.

[0165] <2>

[0166] The active energy ray curable composition according to <1>, wherein the monofunctional monomer (A2) is a monofunctional monomer having a nitrogen atom in the molecule.

[0167] <3>

[0168] The active energy ray-curable composition according to <1> or <2>, wherein the monofunctional monomer (A2) is an N-substituted (meth)acrylamide.

[0169] <4>

[0170] A cured product obtained by curing the active energy ray-curable composition according to any one of <1> to <3>.

[0171] Examples

[0172] The present invention will be specifically described below by way of examples, but the present invention is not limited to these examples.

[0173] Production Example 1 [Synthesis of (meth)acrylate (C-4) having a urethane group]

[0174] 258 parts by weight of polypropylene glycol [trade name "Sunnix PP-2000", manufactured by Sanyo Chemical Industries, Ltd., number average molecular weight: 2000], 65 parts by weight of MDI, and 0.1 part by weight of a urethanization catalyst were charged into a reaction vessel, and reacted at 110 °C for 4 hours. Then, 33 parts by weight of 2-hydroxyethyl acrylate was added, and the reaction was carried out at 80 °C for 8 hours to obtain a bifunctional acrylate (C-4) having a urethane group. The number average molecular weight of (C-4) was 2700.

[0175] <Production of active energy ray-curable composition>

[0176] (Examples 1 to 14 and Comparative Examples 1 to 5)

[0177] According to the blending ratios (parts by weight) in Table 1, the monofunctional monomer (A), the polyfunctional (meth)acrylate (C) having a number average molecular weight of 500 to 40000, the photopolymerization initiator (D), and other monomers (M) were charged into a glass container and stirred until homogeneous to obtain the active energy ray-curable compositions of Examples 1 to 14 and Comparative Examples 1 to 5.

[0178]

[0179]

[0180] It should be noted that the raw materials used in Table 1 are as follows.

[0181] (A1-1): Lauryl acrylate [trade name: LA, manufactured by Osaka Organic Chemical Industry Co., Ltd.] (Tg of homopolymer: -30 °C)

[0182] (A1-2): Isostearyl acrylate [trade name: ISTA, manufactured by Osaka Organic Chemical Industry Co., Ltd.] (Tg of homopolymer: -15 °C)

[0183] (A1-3): 2-[(Butylamino)carbonyl]oxyethyl acrylate [Trade name: Viscoat#216, manufactured by Osaka Organic Chemical Industry Co., Ltd.] (Tg of homopolymer: 0 °C)

[0184] (A1-4): Tetrahydrofurfuryl acrylate [Trade name: Viscoat#150, manufactured by Osaka Organic Chemical Industry Co., Ltd.] (Tg of homopolymer: -12 °C)

[0185] (A2-1): N-Acryloylmorpholine [Trade name: ACMO, manufactured by KJ Chemicals Co., Ltd.] (Tg of homopolymer: 145 °C)

[0186] (A2-2): N,N-Dimethylacrylamide [Trade name: DMAA, manufactured by KJ Chemicals Co., Ltd.] (Tg of homopolymer: 119 °C)

[0187] (A2-3): Isobornyl acrylate [Trade name: Light Acrylate IBXA, manufactured by Kyoeisha Chemical Co., Ltd.] (Tg of homopolymer: 97 °C)

[0188] (A2-4): Cyclic trimethylolpropane formal acrylate [Trade name: Viscoat#200, manufactured by Osaka Organic Chemical Industry Co., Ltd.] (Tg of homopolymer: 27 °C)

[0189] (A2-5): Diacetone acrylamide [Trade name: DAAM, manufactured by KJ Chemicals Co., Ltd.] (Tg of homopolymer: 77 °C)

[0190] (C-1): Polyethylene glycol diacrylate (number average molecular weight of about 1100) [Trade name: NK ESTER A-1000, manufactured by Shin-Nakamura Chemical Co., Ltd.]

[0191] (C-2): Polypropylene glycol diacrylate (number average molecular weight of about 800) [Trade name: NK ESTER APG-700, manufactured by Shin-Nakamura Chemical Co., Ltd.]

[0192] (C-3): Polysiloxane diacrylate (number average molecular weight of about 2500) [Trade name: EBECRYL350, manufactured by DAICEL-ALLNEX Co., Ltd.]

[0193] (C-5): Urethane diacrylate (number average molecular weight of about 18000) [Trade name: UV-3000B, manufactured by Mitsubishi Chemical Corporation]

[0194] (C-6): Urethane diacrylate (number average molecular weight of about 6500) [Trade name: UN-6200, manufactured by Negami Kogyo Co., Ltd.]

[0195] (C-7): Carbamate diacrylate (number average molecular weight of about 20,000) [Trade name: UN-7700, manufactured by Negami Kogyo Co., Ltd.]

[0196] (C-8): Carbamate diacrylate (number average molecular weight of about 35,000) [Trade name: UF-C051, manufactured by Kyoeisha Chemical Co., Ltd.]

[0197] (C-9): Carbamate tetraacrylate (number average molecular weight of about 2,000) [Trade name: EBECRYL 4513, manufactured by DAICEL-ALLNEX Co., Ltd.]

[0198] (M-1): Reaction product of 6-caprolactone addition polymer of 2-hydroxyethyl methacrylate and phosphoric anhydride [Trade name: KAYAMER PM-21, manufactured by Nippon Kayaku Co., Ltd.]

[0199] (M-2): 1,9-Nonanediol diacrylate [Trade name: Viscoat #260, manufactured by Osaka Organic Chemical Industry Co., Ltd.]

[0200] (M-3): Trimethylolpropane triacrylate [Trade name: Viscoat #295, manufactured by Osaka Organic Chemical Industry Co., Ltd.]

[0201] (D-1): (2,4,6-Trimethylbenzoyl) diphenylphosphine oxide [Trade name: Irgacure TPO, manufactured by IGM Resins B.V.]

[0202] (D-2): Bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide [Trade name: Irgacure 819, manufactured by IGM Resins B.V.]

[0203] (D-3): Ethyl 2,4,6-trimethylbenzoyl phenylphosphonate [Trade name: Irgacure TPO-L, manufactured by CHEMBRIDGE]

[0204] (D-4): 1-Hydroxycyclohexyl phenyl ketone [Trade name: Irgacure 184, manufactured by IGM Resins B.V.]

[0205] The initial viscosities, film curing properties, total light transmittances, elastic moduli, elongation rates, recovery rates, and metal adhesions of the respective active energy ray-curable compositions obtained in Examples 1 to 14 and Comparative Examples 1 to 5 were measured or evaluated by the following test methods, and the results are shown in Table 1.

[0206] (1) Measurement of initial viscosity

[0207] The respective active energy ray-curable compositions obtained in Examples 1 to 14 and Comparative Examples 1 to 5 were conditioned at 25°C for 30 minutes, and the initial viscosity (mPa·s) was measured using an E-type viscometer ["VISCOMETER TV-25L" manufactured by Toki Sangyo Co., Ltd.] under the following conditions.

[0208] [Measurement Conditions]

[0209] Conical rotor: Standard conical rotor (1°34’×R24)

[0210] Measurement temperature: 25°C

[0211] Measurement range: M

[0212] Rotation speed: 50 rpm

[0213] (2) Evaluation of film curability

[0214] Each of the active energy ray-curable compositions obtained in Examples 1 to 14 and Comparative Examples 1 to 5 was applied to a surface-treated PET (polyethylene terephthalate) film [COSMOSHINE A4300 manufactured by Toyobo Co., Ltd.] with a thickness of 100 μm to a film thickness of 10 μm using a coater. Subsequently, using an LED light source ultraviolet irradiation device [model "FJ100 150×20 385", manufactured by phoseon TECHNOLOGY Co., Ltd., irradiation wavelength 385 nm], exposure was carried out in a nitrogen atmosphere at an irradiation intensity of 200 mW / cm 2 . The exposure dose was 1000 mJ / cm 2 . For the curability of the cured film immediately after light irradiation and 10 seconds after light irradiation, the presence or absence of stickiness was confirmed by touching with a finger.

[0215] In the case of stickiness, further exposure was carried out in the same manner as above at an irradiation intensity of 200 mW / cm 2 (total exposure dose for the first and second times: 2000 mJ / cm 2 ), and for the curability immediately after light irradiation and 10 seconds after light irradiation, the presence or absence of stickiness was confirmed by touching with a finger. The film curability was evaluated according to the following criteria. The film curability is preferably 2 or more, more preferably 3. In addition, when the evaluation of the film curability is 1, the curability is insufficient, so the evaluation of the total light transmittance, elastic modulus, elongation, recovery rate, and metal adhesion of the cured product is not carried out subsequently.

[0216] [Evaluation Criteria]

[0217] 3: Stickiness disappears when the exposure dose is 1000 mJ / cm 2 .

[0218] 2: The tack disappears when the total exposure dose is 2000 mJ / cm 2 .

[0219] 1: The tack still remains when the total exposure dose is 2000 mJ / cm 2 .

[0220] (3) Evaluation of the total light transmittance of the cured product

[0221] Using a coater, each of the active energy ray-curable compositions obtained in Examples 1 to 14, Comparative Examples 1 to 2, and 4 to 5 was coated on a surface-treated PET (polyethylene terephthalate) film [COSMOSHINE A4300, manufactured by Toyobo Co., Ltd.] with a thickness of 100 μm to a film thickness of 10 μm. Then, using an LED light source ultraviolet irradiation device [model "FJ100 150×20 385", manufactured by phoseon TECHNOLOGY Co., Ltd., irradiation wavelength 385 nm], irradiation was carried out in a nitrogen atmosphere at an irradiation intensity of 200 mW / cm 2 to perform exposure and produce an evaluation sample. The exposure dose was 2000 mJ / cm 2 .

[0222] The produced evaluation sample was conditioned at 25 °C for 30 minutes, and the total light transmittance (%) was measured using a total light transmittance measuring device [trade name "haze-garddual", manufactured by BYK gardner Co., Ltd.] in accordance with JIS K7136:2000. In the present invention, the total light transmittance is preferably 90% or more.

[0223] (4) Evaluation of the elongation rate of the cured product

[0224] [Production of test piece]

[0225] A PET film [trade name: Lumirror S, manufactured by Toray Industries, Inc.] was pasted on a glass plate [trade name: GLASS PLATE, manufactured by AS ONE Co., Ltd., longitudinal 200 mm × transverse 200 mm × thickness 5 mm], and the active energy ray-curable composition was coated using a coater to a cured film thickness of 100 μm. Using an ultraviolet irradiation device [model "VPS / I600", manufactured by Fusion UV Systems Co., Ltd.], ultraviolet rays of 2000 mJ / cm 2 were irradiated in a nitrogen atmosphere to obtain a PET film covered with a cured product of the active energy ray-curable composition.

[0226] The PET film covered with the cured product was punched into a dumbbell shape No. 3 in accordance with JIS K6251:2017, and then the PET film was peeled off to obtain a test piece for measurement.

[0227] <Tensile Test>

[0228] After leaving the obtained test pieces for measurement to stand at 25°C and 50% RH for 5 hours, a tensile test was conducted in accordance with JIS K6251:2017 using a universal testing machine Autograph [model "AG-IS", manufactured by Shimadzu Corporation] to measure the elastic modulus and elongation at break.

[0229] [Measurement Conditions]

[0230] Chuck distance: 20 mm

[0231] Gauge length: 20 mm

[0232] Tensile speed: 10 mm / minute

[0233] Next, the elongation at break (%) was calculated by the following formula (2).

[0234] Elongation at break (%) = (gauge length at break - gauge length) / (gauge length) × 100... (2)

[0235] The elastic modulus was analyzed for the portion where the displacement was 0.01 to 0.05 mm.

[0236] In the present invention, the elastic modulus is preferably 1000 MPa or less, more preferably 500 MPa or less, and further preferably 100 MPa or less. In addition, the elongation at break is preferably 50% or more, more preferably 100% or more.

[0237] <Recovery Rate>

[0238] After leaving the obtained test pieces for measurement to stand at 25°C and 50% RH for 5 hours, they were extended to an elongation at break of 50% in accordance with JIS K6251:2017 using a universal testing machine Autograph [model "AG-IS", manufactured by Shimadzu Corporation], and the recovery rate was calculated after returning the jig to the 0% position and leaving it to stand for 1 hour.

[0239] Recovery rate (%) = (gauge length before the test (20 mm) / gauge length after the test) × 100

[0240] It should be noted that in Comparative Examples 1 and 4, the test pieces were damaged, so the recovery rate could not be calculated.

[0241] In the present invention, the recovery rate is preferably 80% or more, more preferably 90% or more, and further preferably 95% or more.

[0242] (5) Evaluation of Metal Adhesion (to Copper Plate)

[0243] Using a coater, each of the active energy ray-curable compositions obtained in Examples 1 to 14, Comparative Examples 1 to 2, and 4 to 5 was coated on a copper plate (film thickness: 1 mm) to a film thickness of 10 μm. Then, using an LED light source ultraviolet irradiation device [model "FJ100 150×20 385", manufactured by phoseon TECHNOLOGY Co., Ltd., irradiation wavelength: 385 nm], exposure was carried out at an irradiation intensity of 200 mW / cm 2 to produce an evaluation sample. The exposure dose was 2000 mJ / cm 2 . After allowing the obtained evaluation sample to stand in an environment of 23°C and a relative humidity of 50% for 24 hours, the cured coating film on the substrate was cross-cut into 2 mm×2 mm checkerboards (100 pieces), and a cellophane tape was adhered thereto, followed by 90-degree peeling, and the state of peeling of the cured product from the substrate was visually observed. For each sample, two checkerboards were prepared for evaluation, and the average value of the number of squares in which the cured product did not peel and was adhered to the substrate is shown in Table 1. The average value of the number of adhered squares is preferably 80 or more, more preferably 90 or more, and further preferably 100.

[0244] Industrial Applicability

[0245] Both the elongation at break and the elastic modulus of the active energy ray-curable composition of the present invention are excellent, and thus it is useful as a material for various electronic components typified by display components such as flexible displays, stretchable devices, and various optical components. In particular, it can be suitably used for bonding and sealing applications of display components, electronic components such as image sensors, and semiconductor packages. In addition, it can also be widely used for various coating, ink (UV printing ink, UV inkjet printing ink, screen printing ink, etc.) and coating applications.

Claims

1. A radically curable composition containing a monofunctional monomer (A), a polyfunctional (meth)acrylate (C) having a number average molecular weight of 500 to 40,000, and a photopolymerization initiator (D), wherein the monofunctional monomer (A) contains a monofunctional monomer (A1) having a glass transition temperature of the homopolymer below 25°C and a monofunctional monomer (A2) having a glass transition temperature of the homopolymer of 25°C or higher, based on the total weight of the monofunctional monomer (A) and the polyfunctional (meth)acrylate (C), the content of the monofunctional monomer (A) is 10% by weight to 75% by weight, the content of the polyfunctional (meth)acrylate (C) is 25% by weight to 90% by weight, and the content of the photopolymerization initiator (D) is 0.1% by weight to 20% by weight, the molecular weight between crosslinks is 1,000 to 25,000.

2. The active energy ray-curable composition according to claim 1, wherein The monofunctional monomer (A2) is a monofunctional monomer having a nitrogen atom in the molecule.

3. The active energy ray-curable composition according to claim 1, wherein, The monofunctional monomer (A2) is an N-substituted (meth)acrylamide.

4. A cured product obtained by curing the radically curable composition according to any one of claims 1 to 3.

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