Photocurable composition

Abstract

To provide a photocurable composition that has reduced tackiness even in contact with air; gives a cured product having high adhesion and coating strength; and shows high compatibility.SOLUTION: A photocurable composition contains (A) at least one elastomer selected from the group consisting of (A1) a diene elastomer unmodified by a methacryloyl group with no hydrogen added thereto and (A2) a hydrogenated product of the component (A1), a methacryloyl group-bearing monomer (B), a photopolymerization initiator (C) and, as an optional component, a methacryloyl group-bearing oligomer (D). Relative to 100 pts.wt. of the total of the component (A) and the component (B), the content of the component (D) is less than 4 pts.wt. Relative to 100 pts.wt. of the component (B), the content of a polyfunctional monomer (B1) bearing two or more methacryloyl groups in each molecule is 7 pts.wt. or less. If (i) the component (A) comprises the (A2) component, a cured product of the photocurable composition has a storage elastic modulus G' of 1.00×103 Pa or more at 200°C, or (ii) the component (A2) is solid at 25°C.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a photocurable composition.

Background Art

[0002] Curing techniques using active energy rays such as electron beams or ultraviolet rays have become important techniques in various technical fields from the viewpoints of organic solvent emission regulations and reduction of energy consumption in the manufacturing process, and are used in applications such as adhesives, pressure-sensitive adhesives, coating agents, inks, sealing agents, and potting agents.

[0003] Patent Document 1 proposes a method of using an ultraviolet curable resin composition containing a conjugated diene polymer having an average of 1 or more (meth)acryloyl groups per molecule in a predetermined content. Further, Patent Document 2 proposes a method of using a curable resin composition containing elastomer particles in order to obtain a cured product having excellent impact resistance and the like.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] Since the ultraviolet curable resin composition of Patent Document 1 is strongly affected by oxygen inhibition, when irradiated with ultraviolet rays in a state of being in contact with air, the tackiness of the outermost surface becomes remarkable. Further, since the curable resin composition of Patent Document 2 uses particles, it becomes whitened and a problem of transparency occurs.

[0006] Therefore, an object of the present invention is to provide a photocurable composition that can suppress tackiness even when exposed to air, can obtain a cured product having excellent adhesion and film strength, and has good compatibility.

Means for Solving the Problems

[0007] The present invention relates to the following. [1] A photocurable composition comprising at least one elastomer (A) selected from the group consisting of a diene-based elastomer (A1) that is not modified with a (meth)acryloyl group and is non-hydrogenated, and a hydrogenated product (A2) of the component (A1), a monomer (B) having a (meth)acryloyl group, a photopolymerization initiator (C), and an oligomer (D) having a (meth)acryloyl group as an optional component, wherein the component (A2) is solid at 25°C, and the content of the component (D) is less than 4 parts by weight with respect to a total of 100 parts by weight of the components (A) and (B), and the content of a polyfunctional monomer (B1) having two or more (meth)acryloyl groups in the molecule is 7 parts by weight or less with respect to 100 parts by weight of the component (B). [2] A photocurable composition comprising at least one elastomer (A) selected from the group consisting of a diene-based elastomer (A1) that is not modified with a (meth)acryloyl group and is non-hydrogenated, and a hydrogenated product (A3) of the component (A1), a monomer (B) having a (meth)acryloyl group, a photopolymerization initiator (C), and an oligomer (D) having a (meth)acryloyl group as an optional component, wherein the content of the component (D) is less than 4 parts by weight with respect to a total of 100 parts by weight of the components (A) and (B), and the content of a polyfunctional monomer (B1) having two or more (meth)acryloyl groups in the molecule is 7 parts by weight or less with respect to 100 parts by weight of the component (B), provided that when the component (A) contains the component (A3), the storage elastic modulus G' of the cured product of the photocurable composition at 200°C is 1.00×10 3 Pa or more. [3] The photocurable composition according to [1] or [2], wherein the component (C) is a photo radical initiator having two or more 2-hydroxy-2-methyl-1-phenyl-propanone structures in the molecule. [4] The photocurable composition according to any one of [1] to [3], wherein the component (B) contains at least one selected from the group consisting of an alicyclic mono(meth)acrylic monomer, an aromatic mono(meth)acrylic monomer, and a hydroxyl group-containing alkyl mono(meth)acrylic monomer. [5] The photocurable composition according to any one of [1] to [4], wherein the component (A) is the component (A1). [6] A coating agent using the photocurable composition according to any one of [1] to [5]. [7] A potting agent using the photocurable composition according to any one of [1] to [5]. [Effect of the Invention]

[0008] According to the present invention, it is possible to provide a photocurable composition that can suppress tackiness even in a state of being in contact with air, can obtain a cured product excellent in adhesion and film strength, and has good compatibility. [Embodiments for Carrying Out the Invention]

[0009] [Definition of Terms] "(Meth)acrylate" has the meaning of at least one of acrylate and methacrylate. "(Meth)acryloyl group" has the meaning of at least one of acryloyl group and methacryloyl group. "Elastomer (A)" is also referred to as "component (A)". The same applies to "(meth)acryloyl group-containing monomer (B)" and the like. Regarding a numerical range, "~" means including both end values. Also, "below" means "the same or less", and "above" means "the same or more".

[0010] [First Photocurable Composition] The first photocurable composition is a photocurable composition containing at least one elastomer (A) selected from the group consisting of a diene-based elastomer (A1) that is not modified with a (meth)acryloyl group and is not hydrogenated, and a hydrogenated product (A2) of the component (A1), a monomer (B) having a (meth)acryloyl group, a photopolymerization initiator (C), and an oligomer (D) having a (meth)acryloyl group as an optional component. The component (A2) is solid at 25°C. With respect to 100 parts by weight in total of the components (A) and (B), the content of the component (D) is less than 4 parts by weight, and with respect to 100 parts by weight of the component (B), the content of a polyfunctional monomer (B1) having two or more (meth)acryloyl groups in the molecule is 7 parts by weight or less.

[0011] <One or more elastomers (A) selected from the group consisting of (A1) and (A2)> The component (A) is one or more selected from the group consisting of (A1) and (A2). Since the component (A) is not modified with a (meth)acryloyl group, the photocurable composition containing the component (A) has suppressed tackiness (that is, is excellent in suppressing tackiness).

[0012] ≪Component (A1)≫ The component (A1) is a diene-based elastomer (A1) that is not modified with a (meth)acryloyl group and is not hydrogenated. The component (A1) is also called an unhydrogenated product. Further, the component (A1) may be liquid or solid at 25°C. Here, "liquid" means having fluidity at 25°C.

[0013] (A1) The component may be a polymer obtained by polymerizing a monomer containing a conjugated diene compound. Examples of the conjugated diene compound include 1,3-butadiene, isoprene (2-methyl-1,3-butadiene), 2,3-dimethyl-1,3-butadiene, 2-phenylbutadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, 1,3-hexadiene, 1,3-octadiene, 1,3-cyclohexadiene, 2-methyl-1,3-octadiene, 1,3,7-octatriene, myrcene, and chloroprene. The conjugated diene compound may be one kind or a combination of two or more kinds.

[0014] The monomer containing a conjugated diene compound may contain an aromatic vinyl compound as a copolymerizable monomer other than the conjugated diene compound, or may consist only of the conjugated diene compound. Specific examples of the aromatic vinyl compound include styrene, α-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 4-propylstyrene, 4-t-butylstyrene, 4-cyclohexylstyrene, 4-dodecylstyrene, 2,4-dimethylstyrene, 2,4-diisopropylstyrene, 2,4,6-trimethylstyrene, 2-ethyl-4-benzylstyrene, 4-(phenylbutyl)styrene, 1-vinylnaphthalene, 2-vinylnaphthalene, vinylanthracene, N,N-diethyl-4-aminoethylstyrene, vinylpyridine, 4-methoxystyrene, monochlorostyrene, dichlorostyrene, divinylbenzene, etc.

[0015] (A1) The component may be a homopolymer of a conjugated diene compound, a random copolymer or a block copolymer of two or more monomers.

[0016] When the (A1) component is a homopolymer of a conjugated diene compound, polybutadiene, polyisoprene, etc. may be mentioned.

[0017] When the component (A1) is a random copolymer or block copolymer of two or more monomers, it is preferably a block copolymer of two or more monomers, and particularly preferably a block copolymer of a conjugated diene compound and an aromatic vinyl compound. When the component (A1) is a block copolymer, each block may be a block consisting of a single monomer or a block of a random copolymer consisting of two or more monomers. Further, the block copolymer may be a diblock or a triblock. When the block copolymer is a diblock or triblock, an A-B type block copolymer is preferred. When the block copolymer is a triblock, an A-B-A type block copolymer is preferred. Here, A is a block of an aromatic vinyl compound, and B is a block of a conjugated diene compound. When the component (A1) is a block copolymer of a conjugated diene compound and an aromatic vinyl compound, the styrene content in the block copolymer is preferably 10 to 50% by mass.

[0018] (A1) component may be modified by a functional group other than a (meth)acryloyl group. In this case, the (A1) component can have a functional group other than a (meth)acryloyl group. Examples of such a functional group other than a (meth)acryloyl group include a carboxyl group, a carbonyl group, a mercapto group, an isocyanate group, a nitrile group, an acid anhydride group, an amino group, an amide group, an imino group, an imidazole group, a urea group, an alkoxysilyl group, a hydroxyl group, an epoxy group, etc. In the (A1) component, the modification site by a functional group other than a (meth)acryloyl group can be at the terminal or other than the terminal of the polymer. When the modification site by a functional group other than a (meth)acryloyl group is other than the terminal, the functional group may exist as a functional group contained in an intermediate unit. For example, when a polystyrene-polybutadiene-polystyrene copolymer or a polystyrene-polybutadiene copolymer is modified by an epoxy group, the modification site by the epoxy group may be other than the terminal of the polymer. Here, the epoxy group may exist as a functional group contained in an intermediate unit represented by [-CH-CH(O)CH-CH-] between a polystyrene unit and a polybutadiene unit. As a method for producing the (A) component modified by a functional group other than a (meth)acryloyl group, for example, the method described in JP-A-2011-132298 can be referred to.

[0019] Specific examples of the component (A1) include diene homopolymers such as polybutadiene and polyisoprene; diene diblock copolymers such as polystyrene-polybutadiene copolymer and polystyrene-polyisoprene copolymer; and diene triblock copolymers such as polystyrene-polybutadiene-polystyrene copolymer, polystyrene-polyisoprene-polystyrene copolymer, and polystyrene-(random copolymer of polyisoprene and polybutadiene)-polystyrene copolymer. These polymers may all be modified with functional groups other than the (meth)acryloyl group. Specific examples of the component (A1) modified with a functional group other than the (meth)acryloyl group include polyisoprene modified with a carboxyl group, or a polystyrene-polybutadiene-polystyrene copolymer or a polystyrene-polybutadiene copolymer modified with an epoxy group. Note that a polystyrene-polybutadiene-polystyrene copolymer or a polystyrene-polybutadiene copolymer modified with an epoxy group is also called an epoxidized styrene-butadiene block polymer.

[0020] ≪Component (A2)≫ The component (A2) is a hydrogenated product of the component (A1). Also, in the first composition, the component (A2) is solid at 25°C. The component (A2) is a polymer obtained by hydrogenating at least a part of the unsaturated bonds derived from the conjugated diene compound contained in the component (A1). Here, the component (A1) used as the raw material for the component (A2) is as described above, including the preferred range. Also, the component (A2) modified with a functional group other than the (meth)acryloyl group can be obtained by hydrogenating at least a part of the unsaturated bonds contained in the unmodified component (A1) and then performing modification with the functional groups described below.

[0021] ≪Preferred embodiments of component (A)≫ (A) component's weight average molecular weight is not particularly limited, but it is preferably 2,000 or more, and particularly preferably 3,000 to 100,000. As a method for measuring the weight average molecular weight, for components with relatively high molecular weights such as oligomers and polymers, a method of converting the measurement results of gel permeation chromatography (GPC) using a calibration curve of standard polystyrene is generally known.

[0022] (A) component is preferably a non-hydrogenated component. That is, (A) component is preferably (A1) component, and among (A1) components, it is particularly preferably a styrene-isoprene block polymer.

[0023] (A) component preferably consists only of (A) component that is solid at 25°C or is a combination of (A) component that is solid at 25°C and (A1) component that is liquid at 25°C, and particularly preferably consists only of (A) component that is solid at 25°C. Here, the "(A) component that is solid at 25°C" is one or more selected from the group consisting of (A1) component and (A2) component that are solid at 25°C. Also, in the above case, from the viewpoint of more efficiently exerting the effect of the preferred (A) component, the photocurable composition may not contain the content of the (B1) component described later.

[0024] (A) component can use commercially available products. Such commercially available products include Septon (registered trademark, manufactured by Kuraray Co., Ltd.), Hybrar (registered trademark, manufactured by Kuraray Co., Ltd.), Claprene (registered trademark, manufactured by Kuraray Co., Ltd.), Quintac (registered trademark, manufactured by Nippon Zeon Co., Ltd.), TR (registered trademark, manufactured by JSR Corporation), SBR (registered trademark, manufactured by Sumitomo Chemical Co., Ltd.), Epofrend (registered trademark, manufactured by Daicel Corporation), etc. (A) component may be one kind or a combination of two or more kinds.

[0025] <Monomer (B) having a (meth)acryloyl group> (Meta) acryloyl group-containing monomer (B) is not particularly limited as long as it is a monomer having one or more (meta) acryloyl groups. Examples of component (B) include monofunctional monomers having one (meta) acryloyl group in the molecule and polyfunctional monomers having two or more (meta) acryloyl groups in the molecule.

[0026] ≪Monofunctional monomer having one (meta) acryloyl group in the molecule≫ The monofunctional monomer having one (meta) acryloyl group in the molecule is a monofunctional (meta) acrylate monomer, and examples thereof include alicyclic mono (meta) acrylate monomers, aromatic mono (meta) acrylate monomers, hydroxyl group-containing alkyl mono (meta) acrylate monomers, and other mono (meta) acrylate monomers.

[0027] Examples of alicyclic mono (meta) acrylate monomers include isobornyl (meta) acrylate, dicyclopentenyl oxyethyl (meta) acrylate, norbornene (meta) acrylate, dicyclopentanyl (meta) acrylate, cyclohexyl (meta) acrylate, and the like.

[0028] Examples of aromatic mono (meta) acrylate monomers include benzyl (meta) acrylate, phenoxyethyl (meta) acrylate, ethoxylated o-phenylphenol acrylate, phenoxybenzyl (meta) acrylate, naphthalene (meta) acrylate, and the like.

[0029] Examples of hydroxyl group-containing mono (meta) acrylate monomers include hydroxyalkyl (meta) acrylates such as hydroxyethyl (meta) acrylate (e.g., 2-hydroxyethyl (meta) acrylate), hydroxypropyl (meta) acrylate (e.g., 2-hydroxypropyl (meta) acrylate), hydroxybutyl (meta) acrylate (e.g., 4-hydroxybutyl (meta) acrylate), and diethylene glycol monoethyl ether (meta) acrylate.

[0030] Examples of other mono(meth)acrylate monomers include alkyl mono(meth)acrylate monomers, mono(meth)acrylic monomers having a heterocyclic structure, and the like.

[0031] The alkyl group of the alkyl mono(meth)acrylate monomer may be linear or branched. The alkyl group may be either a long chain (C12 - C20) or a short chain (C1 - C11). Examples of the alkyl (meth)acrylate monomer include methyl (meth)acrylate, ethyl (meth)acrylate, tert-butyl (meth)acrylate, isooctyl (meth)acrylate, isomyristyl (meth)acrylate, lauryl (meth)acrylate, and the like. The alkyl mono(meth)acrylate monomer is preferably a C12 - C20 alkyl (meth)acrylate monomer.

[0032] The mono(meth)acrylic monomer having a heterocyclic structure has at least one selected from the group consisting of an oxygen atom and a nitrogen atom as the heteroatom constituting the ring structure. The total number of oxygen atoms and nitrogen atoms in the ring structure is preferably 2 - 4, and particularly preferably 2 - 3. The ring structure may be a monocyclic or polycyclic ring. The total number of atoms constituting one ring structure is not particularly limited, but is preferably 3 - 20. The ring structure is particularly preferably a 5-membered or 6-membered monocyclic heterocyclic ring.

[0033] Examples of the mono(meth)acrylic monomer having a heterocyclic structure include tetrahydrofurfuryl (meth)acrylate, alkoxylated tetrahydrofurfuryl acrylate, caprolactone-modified tetrahydrofurfuryl (meth)acrylate, morpholine (meth)acrylate (such as 4-(meth)acryloylmorpholine), pentamethylpiperidinyl (meth)acrylate, cyclic trimethylolpropane formal (meth)acrylate, and the like.

[0034] ≪Multifunctional Monomers Having Two or More (Meth)acryloyl Groups in the Molecule≫ Examples of the polyfunctional monomer having two or more (meth)acryloyl groups in the molecule (hereinafter sometimes referred to as the “component (B1)”) include bifunctional (meth)acrylate monomers and trifunctional or higher (meth)acrylate monomers.

[0035] Examples of the bifunctional (meth)acrylate monomers include alkylene glycol di(meth)acrylates, polyalkylene glycol di(meth)acrylates, di(meth)acrylates having an ester group-containing diol skeleton, alicyclic di(meth)acrylates, and other bifunctional (meth)acrylate monomers. Examples of the alkylene glycol di(meth)acrylates include 1,4-butanediol di(meth)acrylate, neopentyl glycol diacrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, and the like. Examples of the polyalkylene glycol di(meth)acrylates include diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, and the like. Examples of the di(meth)acrylates having an ester group-containing diol skeleton include hydroxypivalic acid ester neopentyl glycol di(meth)acrylate and the like. Examples of the alicyclic di(meth)acrylates include dicyclopentanyl di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, ethoxylated hydrogenated bisphenol A di(meth)acrylate, and the like. Examples of the other bifunctional (meth)acrylate monomers include hydroxypropyl di(meth)acrylate, diethylene glycol bis(hydroxypropyl (meth)acrylate), propoxylated bisphenol A bis(hydroxyfluoropropyl (meth)acrylate), and the like.

[0036] Examples of polyfunctional (meth)acrylate monomers having three or more functional groups include trimethylolpropane type polyvalent (meth)acrylates, pentaerythritol type polyvalent (meth)acrylates, isocyanurate type polyvalent (meth)acrylates, and the like. Examples of trimethylolpropane type polyvalent (meth)acrylates include trimethylolpropane tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, hydroxypropylated trimethylolpropane tri(meth)acrylate, and the like. Examples of pentaerythritol type polyvalent (meth)acrylates include pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, monohydroxypentaerythritol tri(meth)acrylate, and the like. Examples of isocyanurate type polyvalent (meth)acrylates include tris((meth)acryloxyethyl)isocyanurate, and the like.

[0037] ≪Preferred embodiments of component (B)≫ From the viewpoint of no tack and further film strength, component (B) preferably contains one or more selected from the group consisting of alicyclic mono(meth)acrylic monomers and aromatic mono(meth)acrylic monomers. Here, when component (B) contains an alicyclic mono(meth)acrylic monomer, it may further contain a hydroxy group-containing alkyl mono(meth)acrylic monomer. The molecular weight of component (B) is preferably less than 1,500. Since monomers do not have a molecular weight distribution, the molecular weight of component (B) can be determined from the structural formula. Component (B) may be one kind or a combination of two or more kinds.

[0038] <Photopolymerization initiator (C)> The photoinitiator (C) is not particularly limited as long as it is a compound that generates radicals upon irradiation with energy rays. Component (C) is 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, benzophenone, 2,2-dimethoxy-1,2-diphenylethane-1-one, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoylphenylethoxyphosphine oxide, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone-1, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 2-methyl-1-[4-methylthio]phenyl]-2-morpholinopropan-1-one, oligo[2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanone], oligo[2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanone], benzoin methyl ether, benzoin ethyl ether, benzoin isobutyl ether, benzoin isopropyl ether, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, oligo 2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanol, oligo 2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanol, 2-hydroxy-2-methyl-1-phenyl-1-propanone, isopropylthioxanthone, methyl o-benzoylbenzoate, [4-(methylphenylthio)phenyl]phenylmethane, 2,4-diethylthioxanthone, 2-chlorothioxanthone, benzophenone, ethylanthraquinone, benzophenone ammonium salt, thioxanthone ammonium salt, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethyl-pentylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethyl-pentylphosphine oxide, 2,4,6-trimethylbenzophenone, 4-methylbenzophenone, 4,4’-bisdiethylaminobenzophenone, 1,4-dibenzoylbenzene, 10-butyl-2-chloroacridone, 2,2’bis(o-chlorophenyl)4,5,4’,5’-tetrakis(3,4,5 - Trimethoxyphenyl)1,2’ - biimidazole, 2,2’ - bis(o - chlorophenyl)4,5,4’,5’ - tetraphenyl - 1,2’ - biimidazole, 4 - benzoyldiphenyl ether, acrylated benzophenone, bis(η5 - 2,4 - cyclopentadien - 1 - yl) - bis(2,6 - difluoro - 3 - (1H - pyrrol - 1 - yl) - phenyl)titanium, o - methylbenzoyl benzoate, ethyl p - dimethylaminobenzoate, isoamyl ethyl p - dimethylaminobenzoate, active tertiary amine, carbazole - phenone - based photoinitiator, acridine - based photoinitiator, triazine - based photoinitiator, benzoyl - based photoinitiator, etc. can be mentioned.,

[0039] Examples of commercially available products of component (C) include KIP - 150 manufactured by DKSH Japan, Omnirad (registered trademark) series such as Omnirad184, Omnirad819, Omnirad127, Omnirad1173 manufactured by IGM Resins B.V., Darocur (registered trademark) series such as Darocur1173, Lucirin (registered trademark) series such as Lucirin TPO, ESACURE 1001M manufactured by ESACUR Japan Sieber Hegner, etc.

[0040] ≪Preferred embodiments of component (C)≫ From the viewpoint of further suppressing tackiness, component (C) is preferably a photo - radical initiator having two or more 2 - hydroxy - 2 - methyl - 1 - phenyl - propanone structures in the molecule. Component (C) may be one kind or a combination of two or more kinds.

[0041] <Oligomer (D) having a (meth)acryloyl group> The photocurable composition contains, as an optional component, an oligomer (D) having a (meth)acryloyl group. The photocurable composition may or may not contain the component (D). The component (D) is not particularly limited as long as it is an oligomer having one or more (meth)acryloyl groups in the molecule. Examples of the component (D) include urethane (meth)acrylate oligomer, epoxy (meth)acrylate oligomer, and the like.

[0042] Examples of the urethane (meth)acrylate oligomer include aromatic, aliphatic, polyether, polycarbonate, polyester, or a combination thereof polyurethane (meth)acrylate oligomer.

[0043] Commercially available products of urethane (meth)acrylate oligomer include, in addition to those described in the examples, EBECRYL4858 (manufactured by Daicel Ornex Co., Ltd.), UN-2301 (manufactured by Negami Chemical Co., Ltd.), EBECRYL4859 (manufactured by Daicel Ornex Co., Ltd.), EBECRYL4738 (manufactured by Daicel Ornex Co., Ltd.), and the like.

[0044] The epoxy (meth)acrylate oligomer is an oligomer in which all epoxy groups in the epoxy resin have reacted with (meth)acrylic acid. The epoxy (meth)acrylate oligomer may contain an oligomer in which some of the epoxy groups in the epoxy resin have reacted with (meth)acrylic acid, that is, an oligomer having an epoxy group and a (meth)acryloyl group in the resin. Here, examples of the epoxy resin include aromatic epoxy resin, aliphatic epoxy resin, alicyclic epoxy resin, and other epoxy resins. The epoxy (meth)acrylate oligomer is preferably an epoxy (meth)acrylate oligomer of an aromatic epoxy resin.

[0045] Commercially available products of epoxy (meth)acrylate oligomer include EB3700 (manufactured by Daicel Ornex) and EB3708 (manufactured by Daicel Ornex).

[0046] The number of (meth)acryloyl groups in the (meth)acrylate oligomer is preferably from 1 to 6, more preferably from 1 to 4, and particularly preferably from 1 to 2.

[0047] The weight average molecular weight of component (D) is preferably 1,500 or more, and particularly preferably from 1,500 to 30,000.

[0048] As a method for measuring the weight average molecular weight, for components with relatively high molecular weights such as oligomers and polymers, a method of converting the measurement results of gel permeation chromatography (GPC) using a calibration curve of standard polystyrene is generally known.

[0049] Component (D) may each be one kind or a combination of two or more kinds.

[0050] <Further component (E)> The photocurable composition may contain a further component (E) as necessary, as long as the effects of the present invention are not impaired. Examples of component (E) include silane coupling agents, surfactants, curing accelerators, tackifiers, plasticizers, antioxidants, ultraviolet absorbers, stabilizers, softeners, defoamers, colorants, fillers, fragrances, etc. Component (E) is not particularly limited as long as it is a component usually used in photocurable compositions, and can be appropriately selected according to the purpose. Component (E) may each be one kind or a combination of two or more kinds.

[0051] (Content of each component) In the photocurable composition, the contents of component (D) and component (B1) are as follows. In the photocurable composition, the content of component (D) is less than 4 parts by weight with respect to a total of 100 parts by weight of components (A) and (B). When the content of component (D) is 4 parts by weight or more with respect to a total of 100 parts by weight of components (A) and (B), the compatibility is poor, and turbidity due to phase separation is likely to occur. From the viewpoint of better compatibility, the content of component (D) is preferably less than 3 parts by weight, and particularly preferably 2 parts by weight or less, with respect to a total of 100 parts by weight of components (A) and (B). In the photocurable composition, the content of component (D) may be 0 parts by weight or more with respect to a total of 100 parts by weight of components (A) and (B).

[0052] In the photocurable composition, the content of component (B1) is 7 parts by weight or less, preferably 5 parts by weight or less, with respect to a total of 100 parts by weight of component (B). When the content of component (B1) exceeds 7 parts by weight with respect to a total of 100 parts by weight of component (B), the compatibility is poor, and turbidity due to phase separation is likely to occur. From the viewpoint of not causing phase separation and the like, the content of component (B1) is preferably 0 to 7 parts by weight, and particularly preferably 0 to 5 parts by weight, with respect to a total of 100 parts by weight of component (B). Further, from the above viewpoint, the content of component (B1) may be 0 to 4 parts by weight or 0 to 3 parts by weight. Also, from the viewpoint of improving the film strength, the content of component (B1) may be 0.5 to 7 parts by weight or 3 to 5 parts by weight with respect to a total of 100 parts by weight of component (B). Therefore, the photocurable composition may or may not contain component (B1). That is, component (B) may consist only of a monofunctional monomer having one (meth)acryloyl group in the molecule, or may be a combination of a monofunctional monomer having one (meth)acryloyl group in the molecule and component (B1).

[0053] In the photocurable composition, the content of each component is preferably as follows. The content of component (A) is preferably 20 parts by weight or more, more preferably 20 to 70 parts by weight, and particularly preferably 30 to 60 parts by weight, based on 100 parts by weight in total of components (A) and (B) from the viewpoints of handling such as viscosity.

[0054] The content of component (C) is preferably 1 to 10 parts by weight, more preferably 2 to 8 parts by weight, and particularly preferably 3 to 7 parts by weight, based on 100 parts by weight in total of components (A) and (B) from the viewpoints of further suppressing tackiness and the like.

[0055] The total content of components (A) to (D) is preferably 50 to 100% by weight, more preferably 60 to 98% by weight, and particularly preferably 70 to 95% by weight in the photocurable composition. The balance is component (E).

[0056] [Second Photocurable Composition] The second photocurable composition is a photocurable composition containing at least one elastomer (A) selected from the group consisting of a diene-based elastomer (A1) that is not (meth)acryloyl group-modified and hydrogen-unadded, and a hydrogenated product (A3) of component (A1), a monomer (B) having a (meth)acryloyl group, a photopolymerization initiator (C), and an oligomer (D) having a (meth)acryloyl group as an optional component, wherein the content of component (D) is less than 4 parts by weight based on 100 parts by weight in total of components (A) and (B), and the content of a polyfunctional monomer (B1) having two or more (meth)acryloyl groups in the molecule is 7 parts by weight or less based on 100 parts by weight of component (B). However, when component (A) contains component (A3), the storage elastic modulus G' at 200 °C of the cured product of the photocurable composition is 1.00×10 3 Pa or more.

[0057] In the second photocurable composition, when component (A) contains component (A3), the storage elastic modulus G' at 200 °C of the cured product of the photocurable composition is 1.00×10 3It is 1.00×10 3 Pa or more. When the (A) component contains the (A3) component, the storage elastic modulus G' at 200 °C of the cured product of the photocurable composition is preferably 1.00×10 9 Pa or more and 1.00×10 3 Pa or less, and particularly preferably 1.00×10 8 Pa or more and 5.00×10

[0058] In the second photocurable composition, the storage elastic modulus G' is preferably the storage elastic modulus of the cured product obtained by performing UV irradiation such that the integrated light amount becomes 12,000 mJ / cm 2 at an illuminance of 200 mW / cm 2 . Further, the wavelength of the UV light in the UV irradiation is preferably 300 to 450 nm.

[0059] In the second photocurable composition, the (A3) component does not have to be solid at 25 °C. That is, the (A3) component includes the (A2) component. Examples of the (A3) component other than the (A2) component include components that are liquid at 25 °C. Here, "liquid" is as described above for the (A1) component. Commercially available products of the (A3) component other than the (A2) component include LIR290 (manufactured by Kuraray Co., Ltd.), GI3000 (manufactured by Nippon Soda Co., Ltd.), and the like.

[0060] Further, the second photocurable composition can contain a further component (E) as necessary, as long as the effects of the present invention are not impaired.

[0061] In the second photocurable composition, the (A1) component, (A2) component, (B) component, (C) component, (D) component, (E) component, and the content of each component are as described in the first photocurable composition, including preferred embodiments.

[0062] [Method for producing the first and second photocurable compositions] The photocurable composition is obtained by a production method including a step of mixing the (A) component, (B) component, (C) component, and a further component (the (D) component, (E) component) which is an optional component.

[0063] [Method for Curing the First and Second Photocurable Compositions] The photocurable composition can be cured by irradiating it with energy rays. The energy rays are not particularly limited, and active energy rays such as visible light, ultraviolet rays, X-rays, and electron beams can be used. The energy rays are preferably ultraviolet rays. As the light source for ultraviolet rays, a light source that emits ultraviolet rays (UV) can be used. Examples of the light source for ultraviolet rays include metal halide lamps, high-pressure mercury lamps, xenon lamps, mercury xenon lamps, halogen lamps, pulsed xenon lamps, LEDs, and the like. The integrated light amount of the energy rays is, for example, preferably 500 to 20,000 mJ / cm 2 at 365 nm, and particularly preferably 1,000 to 15,000 mJ / cm 2 .

[0064] [Uses of the First and Second Photocurable Compositions] The photocurable composition is not strongly affected by oxygen inhibition, and even when irradiated with energy rays in a state of being in contact with air, the tackiness of the outermost surface is suppressed. Therefore, it can be applied to coating agents (including masking agents, etc.) and / or potting agents (including liquid gaskets, etc.) for the purpose of protecting the surfaces of printed wiring boards, electronic components, optical fibers, automotive parts, and the like. In addition, since the photocurable composition has good compatibility, the resulting cured product tends to have excellent transparency. Therefore, the photocurable composition can be applied to optical adhesives and coating agents that require transparency. As a method of using the photocurable composition as a coating agent, a potting agent, or an optical adhesive, a conventionally known method can be applied. As a method of using the photocurable composition as a coating agent or a potting agent, at least a step of applying the photocurable composition to at least a part of a substrate that requires protection, and a step of irradiating the energy rays to cure the photocurable composition to obtain a cured product layer of the photocurable composition are included. Further, when the photocurable composition is used as a masking agent, a step of removing the cured product layer of the photocurable composition can be further included.

[0065] The material of the substrate is not particularly limited, but a substrate made of a material capable of transmitting energy rays (preferably ultraviolet rays) is preferred. Examples of such materials capable of transmitting ultraviolet rays include quartz, glass, plastics, and the like.

[0066] The method of applying the photocurable composition to the substrate is not particularly limited, and examples include brush coating, screen printing, gravure printing, spray coating, dip coating, bar coater, roll coater, spin coater, die coater, dispenser, and other known coating means. The thickness of the layer formed by applying the photocurable composition is not particularly limited, but is preferably 10 to 500 μm, and particularly preferably 30 to 350 μm. Examples of the method for curing the photocurable composition include the methods described above.

Examples

[0067] The present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. The values in the tables are parts by weight unless otherwise specified.

[0068] (Components used) <Component (A)> <<Component (A1): A diene-based elastomer that is not modified with a (meth)acryloyl group and is not hydrogenated>> ·Component (A1) that is solid at 25°C QTC3620: Styrene-isoprene block polymer (manufactured by Nippon Zeon Co., Ltd.) QTC3520: Styrene-isoprene block polymer (manufactured by Nippon Zeon Co., Ltd.) QTC3280: Styrene-isoprene block polymer (manufactured by Nippon Zeon Co., Ltd.) AT501: Epoxidized styrene-butadiene block polymer (manufactured by Daicel Corporation) CT310: Epoxidized styrene-butadiene block polymer (manufactured by Daicel Corporation) ·Component (A1) that is liquid at 25°C LIR410: Liquid carboxylated polyisoprene (manufactured by Kuraray Co., Ltd.) LBR305: Liquid polybutadiene (manufactured by Kuraray Co., Ltd.) LIR310: Liquid styrene-isoprene block polymer (manufactured by Kuraray Co., Ltd.) LIR390: Liquid styrene-isoprene block polymer (manufactured by Kuraray Co., Ltd.) G3000: Liquid polybutadiene with hydroxyl groups at both ends (manufactured by Nippon Soda Co., Ltd.) B3000: Liquid 1,2-polybutadiene homopolymer (manufactured by Nippon Soda Co., Ltd.) <<(Component (A2) and Component (A3): Hydrogenated product of Component (A1) (solid at 25°C))>> SEP2002: Hydrogenated styrene-isoprene block polymer (manufactured by Kuraray Co., Ltd.) SEP8076: Hydrogenated styrene-butadiene block polymer (manufactured by Kuraray Co., Ltd.) <<(Component (A3): Hydrogenated product of Component (A1) (liquid at 25°C))>> LIR290: Liquid hydrogenated polyisoprene (manufactured by Kuraray Co., Ltd.) GI3000: Liquid hydrogenated polybutadiene with hydroxyl groups at both ends (manufactured by Nippon Soda Co., Ltd.) <Other polymer components> LA2250: Acrylic block polymer (manufactured by Kuraray Co., Ltd.) LA2250 is solid at 25°C.

[0069] <Component (B)> IBOA: Isobornyl acrylate (manufactured by Nippon Shokubai Co., Ltd.) A-BZ: Benzyl acrylate (manufactured by Shin-Nakamura Chemical Co., Ltd.) 4HBA: 4-Hydroxybutyl acrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd.) <<(Polyfunctional monomer (B1) having two or more (meth)acryloyl groups in the molecule)>> V#802: Tripentaerythritol acrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd.)

[0070] <Component (C)> KIP-150: 2-Hydroxy-2-methyl-1-phenyl-propanone multimer (manufactured by DKSH Japan) Omnirad 127: 2-Hydroxy-2-methyl-1-phenyl-propanone dimer (manufactured by IGM Resins B.V.)

[0071] <(Component (D))> UV3630 ID80: Urethane acrylate oligomer (manufactured by Mitsubishi Chemical Corporation)

[0072] [Manufacture of photocurable composition] According to the compounding ratios shown in the table, each raw material was weighed in an arbitrary amount, and while heating at 60 °C, it was stirred for 2 to 24 hours to prepare a uniform liquid (liquid photocurable composition).

[0073] [Compatibility (appearance of liquid)] After 24 hours had passed since the liquid was prepared, the appearance of the liquid was evaluated according to the following criteria. 〇: Transparent △: Slightly turbid (appears slightly white) ×: Turbid

[0074] [Preparation of test piece] The prepared liquid was applied to a metal plate to a thickness of 10 mm × 10 mm × 0.05 mm, and irradiated with UV light of wavelength 365 nm at an illuminance of 400 mW / cm 2 so that the integrated light quantity became 3,000 mJ / cm 2 to cure the liquid and obtain a test piece.

[0075] [Surface tackiness] After pressing a finger against the surface of the cured product on the test piece and then pulling it away, the surface tackiness was evaluated according to the following criteria. 〇: No tack at all △: Slightly tacky but no problem. ×: Strong tack, problem exists.

[0076] [Adhesion, film strength] The cured product was peeled off by hand from the test piece. The resistance during peeling was evaluated as adhesion according to the following criteria. Also, the breaking tendency of the cured product during peeling was evaluated as film strength according to the following criteria. Adhesion 〇: There is resistance ×: There is no resistance Film strength 〇: Does not break △: Difficult to break ×: Easily breaks

[0077] 〔Rheometer measurement (crosslink density)〕 Set the liquid into a rheometer (MCR302 manufactured by Anton Paar), and using a spot UV irradiation device (LC8 manufactured by Hamamatsu Photonics), irradiate with light of wavelength 365 nm at an illuminance of 200 mW / cm 2 to a cumulative light amount of 12,000 mJ / cm 2 and perform UV irradiation to cure the liquid. Raise the temperature from 25°C to 200°C at 2°C / min and measure the storage elastic modulus G'. The shape of the cured product was 8 mmφ × 0.5 mmt, the measurement frequency was 1 Hz, and the displacement was 1%. The crosslink density was evaluated according to the following criteria.

[0078] 〇: The storage elastic modulus G' at 200°C is 1×10 3 Pa or more, and the absolute value of the change rate of the storage elastic modulus G' at 125°C and 150°C is 50% or less (sufficiently crosslinked) Change rate = (Storage elastic modulus G' at 125°C - Storage elastic modulus G' at 150°C) / Storage elastic modulus G' at 125°C × 100 △: The storage elastic modulus G' at 200°C is 1×10 3 Pa or more (slightly crosslinked) ×: The storage elastic modulus G' at 200°C is less than 1×10 3 Pa (not crosslinked)

[0079] The results are shown in the following table. The values of the blending amounts of each component are all in parts by weight. Also, "*" in component (A) in the table indicates that it is liquid at 25°C.

[0080]

Table 1

[0081]

Table 2

[0082]

Table 3

[0083]

Table 4

[0084] From Tables 1 to 4, it was found that the photocurable compositions of the examples were excellent in compatibility, had suppressed tackiness even when exposed to air (i.e., were excellent in suppressing tackiness), and could obtain cured products excellent in adhesion and film strength.

[0085] From the results of Examples 1 to 3, 5 to 9, and 13 to 21, when the (A) component was the (A1) component or the (A2) component that was solid at 25°C, any one of the suppression of tackiness, adhesion, and film strength was more excellent than when the (A) component contained the (A1) component that was liquid at 25°C. From the results of Examples 6, 10, and 11 and Example 12, the film strength was improved by adding a small amount of the (B1) component. From the results of Examples 13 to 14 and Examples 5 and 15 to 16, when the (A) component was the (A2) component (or the (A3) component that was solid at 25°C) compared to when the (A) component was the (A1) component that was liquid at 25°C, the adhesion and film strength were more excellent even though the crosslinking density was slight.

[0086] On the other hand, in the compositions of Comparative Examples 1 to 2, since the content of the (D) component was 4 parts by weight or more based on 100 parts by weight in total of the (A) component and the (B) component, the compatibility of the composition was poor. In the composition of Comparative Example 3, since the content of the (B1) component exceeded 7 parts by weight based on 100 parts by weight in total of the (B) component, the compatibility of the composition was poor. The compositions of Comparative Examples 4 to 5 contained a diene-based hydrogenated elastomer that was liquid at 25°C as the (A) component, and the storage elastic modulus G' at 200°C of the obtained cured product was 1.00×103 Since it was less than Pa, the film strength and tackiness were inferior. The composition of Comparative Example 6 is a composition containing an acrylic block polymer instead of the component (A). The composition of Comparative Example 6 had inferior film strength. Also, from the comparison between Examples 13 and 14 and Comparative Examples 4 and 5, even when the component (A) contains the component (A3) other than (A2) as a hydrogenated product, the storage elastic modulus G' of the obtained cured product at 200 °C is 1.00×10 3 When it was less than Pa, the suppression of tackiness, adhesion, compatibility, etc. were inferior.

Claims

1. One or more elastomers (A) selected from the group consisting of a diene elastomer (A1) that is not modified with a (meth)acryloyl group and is non-hydrogenated, and a hydrogenated product (A2) of the component (A1), a monomer (B) having a (meth)acryloyl group, a photoinitiator (C), and an oligomer (D) having a (meth)acryloyl group as an optional component, wherein the photo-curable composition is such that: The component (A2) is solid at 25°C. The component (C) is a photo radical initiator having two or more 2-hydroxy-2-methyl-1-phenyl-propanone structures in the molecule. The content of the component (D) is less than 4 parts by weight with respect to a total of 100 parts by weight of the components (A) and (B), and The content of the polyfunctional monomer (B1) having two or more (meth)acryloyl groups in the molecule is 7 parts by weight or less with respect to 100 parts by weight of the component (B). A photo-curable composition.

2. The photo-curable composition according to claim 1, wherein the component (B) includes one or more selected from the group consisting of an alicyclic mono(meth)acrylic monomer and an aromatic mono(meth)acrylic monomer.

3. When the component (A) contains the component (A2), the storage elastic modulus G' at 200 °C of the cured product of the photocurable composition is 1.00×10 ３ Pa or more. The photocurable composition according to claim 1 or 2.

4. The photo-curable composition according to claim 1 or 2, wherein the component (A) is the component (A1).

5. A coating agent using the photo-curable composition according to any one of claims 1 to 4.

6. A potting agent using the photo-curable composition according to any one of claims 1 to 4.

7. A potting agent using a photo-curable composition including one or more elastomers (A) selected from the group consisting of a diene elastomer (A1) that is not modified with a (meth)acryloyl group and is non-hydrogenated, and a hydrogenated product (A2) of the component (A1), a monomer (B) having a (meth)acryloyl group, a photoinitiator (C), and an oligomer (D) having a (meth)acryloyl group as an optional component, wherein The component (A2) is solid at 25°C. The content of the component (D) is less than 4 parts by weight with respect to a total of 100 parts by weight of the components (A) and (B), and The content of the polyfunctional monomer (B1) having two or more (meth)acryloyl groups in the molecule is 7 parts by weight or less with respect to 100 parts by weight of the component (B). A potting agent. The potting agent according to claim 7, wherein the component (B) contains at least one selected from the group consisting of an alicyclic mono(meth)acrylic monomer and an aromatic mono(meth)acrylic monomer. The potting agent according to claim 7 or 8, wherein when the component (A) contains the component (A2), the storage elastic modulus G' at 200°C of the cured product of the photocurable composition is 1.00 × 10 3 Pa or more. The potting agent according to claim 7 or 8, wherein the component (A) is the component (A1).

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