Active energy ray-curable composition

Abstract

To provide an active energy ray-curable composition which gives a cured product having excellent mechanical properties, weather resistance and heat resistance, especially weather resistance and elongation.SOLUTION: An active energy ray-curable composition comprises: a (meth)acrylic polymer (A) modified with an unsaturated double bond-containing oligomer (a2) having a glass transition temperature (Tg) of -30 to -90°C; and an isocyanate compound (B). The (A) component may be a polymer obtained by adding the oligomer (a2) to a copolymer (a1) comprising a constitutional unit derived from a (meth)acrylic monomer having no reactive group and a constitutional unit derived from a (meth)acrylic monomer having a reactive group selected from the group consisting of an epoxy group, a carboxyl group, a hydroxyl group, and an isocyanate group via the reactive group. This composition can be suitably used for applications including a coating agent such as a paint and the like, adhesives and the like.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an active energy ray-curable composition which provides a cured product having excellent weather resistance, heat resistance, and mechanical properties, and which can be suitably used for applications such as coating agents such as paints and adhesives. [Background technology]

[0002] Active energy ray-curable compositions can be cured by exposure to active energy rays such as ultraviolet rays, visible light, and electron beams for a very short period of time, and are highly productive, so they are widely used in inks, coating agents, adhesives, and the like.

[0003] For example, in the case of a top coating agent for decorative films, the cured product is required to have high elongation and strength, and when used outdoors, high weather resistance is also required.

[0004] As the top coating agent, Patent Document 1 proposes a composition containing a (meth)acrylic resin having a (meth)acryloyl group in the side chain and a urethane (meth)acrylate. However, since the composition contains a certain amount or more of urethane acrylate in order to achieve elongation, there is a problem in that the weather resistance is insufficient.

[0005] Meanwhile, Patent Document 2 proposes an active energy ray-curable composition for forming optical films such as polarizer protective films, which contains a (meth)acrylate polymer having an acryloyl group in a side chain and in which the acryloyl group is separated from the main chain by a certain distance or more. However, although the cured product of this polymer has excellent mechanical properties such as elongation, it has the problem of insufficient weather resistance.

[0006] Therefore, the applicant has already proposed that the mechanical properties, weather resistance, and heat resistance of the cured product be improved by using, as a curable component of an active energy ray-curable composition, a (meth)acrylate polymer (A) modified with an unsaturated double bond-containing oligomer having a glass transition temperature (Tg) of −30 to −90°C. However, further improvements in the weather resistance and elongation of the cured product are expected (Patent Document 3). [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-132288 [Patent Document 2] Japanese Patent Application Laid-Open No. 2014-115538 [Patent Document 3] Patent Application No. 2019-237240 Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention provides an active energy ray-curable composition that gives a cured product excellent in mechanical properties, weather resistance, and heat resistance, particularly excellent in weather resistance and elongation. [Means for solving the problem]

[0009] As a result of intensive research to solve the above-mentioned problems, the present inventors have found that an active energy ray-curable composition containing a polymer (A) obtained by modifying a (meth)acrylate polymer with an unsaturated double bond-containing oligomer (a2) having a glass transition temperature (Tg) of −30 to −90° C., and an isocyanate compound (B), can solve the above-mentioned problems and can be suitably used for coating agents such as paints and adhesives, thereby completing the present invention.

[0010] The present invention relates to an active energy ray-curable composition containing a (meth)acrylate polymer (A) [hereinafter also referred to as "component (A)"] modified with an unsaturated double bond-containing oligomer (a2) [hereinafter also referred to as "unsaturated oligomer (a2)"] having a glass transition temperature (hereinafter also referred to as "Tg") of -30 to -90°C, and an isocyanate compound (B) [hereinafter also referred to as "component (B)"]. The component (A) is preferably a reaction product of a copolymer (a1) (hereinafter also referred to as "copolymer (a1)") having a structural unit derived from a (meth)acrylate monomer (a1-1) having no reactive group and a structural unit derived from a (meth)acrylate monomer (a1-2) having a reactive group, and an unsaturated oligomer (a2) having a group reactive with the reactive group and an ethylenically unsaturated group. Furthermore, the (meth)acrylate monomer (a1-2) having a reactive group constituting the copolymer (a1) is preferably a (meth)acrylate monomer having a reactive group selected from the group consisting of an epoxy group, a carboxyl group, a hydroxyl group, and an isocyanate group. Furthermore, it is preferable that the (meth)acrylate monomer (a1-2) having a reactive group constituting the copolymer (a1) is a (meth)acrylate monomer having an epoxy group, and the unsaturated oligomer (a2) is an oligomer having a carboxyl group. In the component (A), the unsaturated oligomer (a2) is preferably a (meth)acrylate oligomer. In the component (A), the unsaturated oligomer (a2) is preferably an oligomer containing a ring-opened caprolactone structure. The weight average molecular weight (Mw) of the component (A) is preferably 2,000 to 60,000.

[0011] In another embodiment of the present invention, a composition further containing an organic solvent (C) (hereinafter also referred to as "component (C)") is preferred, and a composition containing component (C) in a proportion of 70 parts by weight or less per 100 parts by weight of component (A) is preferred. Furthermore, in the present invention, a composition containing an ethylenically unsaturated compound (D) (hereinafter also referred to as "component (D)") is preferred, and a composition containing component (C) in an amount of 70 parts by weight or less per 100 parts by weight of the total of components (A) and (D) is preferred. The composition of the present invention preferably further contains a photopolymerization initiator (E).

[0012] The composition of the present invention is preferably used as an active energy ray-curable composition for coating agents and an active energy ray-curable composition for adhesives. [Effects of the Invention]

[0013] The active energy ray-curable composition of the present invention uses, as active ingredients, a (meth)acrylate polymer (A) modified with an unsaturated double bond-containing oligomer (a2) having a Tg of −30 to −90°C and an isocyanate compound (B) in combination. Therefore, the cured product thereof is excellent in mechanical properties, weather resistance, and heat resistance, particularly in both weather resistance and mechanical properties, and can be suitably used for applications such as coating agents for paints and adhesives. DETAILED DESCRIPTION OF THE INVENTION

[0014] The present invention relates to an active energy ray-curable composition containing component (A) and component (B). The present invention will be described in detail below. The component (A), the component (B), the active energy ray-curable composition, and the method of use will be described below. In the present invention, the term "(meth)acrylate polymer" refers to a polymer containing (meth)acrylate as a main component of the structural unit, the term "(meth)acrylate" refers to acrylate and / or methacrylate, the term "(meth)acrylic" refers to acrylic and / or methacrylic, and the term "(meth)acryloyl" refers to acryloyl and / or methacryloyl.

[0015] 1. Component (A) The component (A) is a (meth)acrylate polymer modified with an unsaturated oligomer (a2). As described above, the (meth)acrylate polymer refers to a polymer containing (meth)acrylate as the main component of the structural units, and refers to a polymer containing 80 to 100% by weight of (meth)acrylate in all structural monomer units. The component (A) is preferably a reaction product of a copolymer (a1) consisting of a structural unit derived from a (meth)acrylate monomer (a1-1) (hereinafter also referred to as "monomer (a1-1)") that does not have a reactive group and a structural unit derived from a (meth)acrylate monomer (a1-2) (hereinafter also referred to as "monomer (a1-2)") that has a reactive group, and an unsaturated oligomer (a2) that has a group that reacts with the reactive group and an ethylenically unsaturated group. That is, as component (A), a polymer having an ethylenically unsaturated group bonded as a side chain, obtained by reacting a reactive group of the backbone polymer (a1) with a reactive group of the unsaturated oligomer (a2), is preferred. The copolymer (a1), the unsaturated oligomer (a2), the method for producing the component (A), and the physical properties of the component (A) will be described below.

[0016] (1) Copolymer (a1) Copolymer (a1), which is the raw material copolymer of component (A), is a copolymer comprising structural units derived from monomer (a1-1) and structural units derived from monomer (a1-2). The monomer (a1-1) and the monomer (a1-2) will be described below.

[0017] (1-1) Monomer (a1-1) The monomer (a1-1) is a (meth)acrylate monomer (a1-1) having no reactive group. Specific examples of the monomer (a1-1) are not particularly limited as long as they are (meth)acrylate-based monomers that do not have the above-mentioned reactive group, and include, for example, alkyl (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, i-butyl (meth)acrylate, t-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, tetradecyl (meth)acrylate, and stearyl (meth)acrylate; alicyclic (meth)acrylates such as isobornyl (meth)acrylate, cyclohexyl (meth)acrylate, dicyclopentanyl (meth)acrylate, and dicyclopentenyl (meth)acrylate; N-(meth)acryloylmorpholine; Acrylamides such as (meth)acrylamide, N-methylolacrylamide, N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, and N,N-dimethylaminopropyl(meth)acrylamide; and Examples include acrylonitrile and methacrylonitrile.

[0018] (1-2) Monomer (a1-2) The monomer (a1-2) is a (meth)acrylate monomer having a reactive group. The monomer (a1-2) is preferably a (meth)acrylate monomer having a reactive group selected from the group consisting of an epoxy group, a carboxyl group, a hydroxyl group, and an isocyanate group.

[0019] Examples of the monomer (a1-2) having an epoxy group as a reactive group include glycidyl (meth)acrylate, 3,4-epoxycyclohexyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate glycidyl ether.

[0020] Examples of the monomer (a1-2) having a hydroxyl group as a reactive group include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and an ε-caprolactone adduct of 2-hydroxyethyl (meth)acrylate.

[0021] An example of the monomer (a1-2) having an isocyanate group as a reactive group is (meth)acryloxyethyl isocyanate, and specific products include "Karenz MOI" and "Karenz AOI" (both trade names, manufactured by Showa Denko).

[0022] Examples of the monomer (a1-2) having a carboxyl group as a reactive group include (meth)acrylic acid, phthalic acid monohydroxyethyl acrylate, ω-carboxy-polycaprolactone (n≈2) monoacrylate, (meth)acryloyloxyethyl succinate, (meth)acryloyloxyethyl hexahydrophthalate, (meth)acryloyloxyethyl phthalate, (meth)acryloyloxyethyl-2-hydroxyethyl phthalate, β-carboxyethyl acrylate, a phthalic anhydride adduct of pentaerythritol triacrylate, a succinic anhydride adduct of pentaerythritol triacrylate, a succinic anhydride adduct of dipentaerythritol triacrylate, and a phthalic anhydride adduct of dipentaerythritol triacrylate.

[0023] (1-3) Polymerization method of copolymer (a1) The method for producing the copolymer (a1) before modification with the unsaturated oligomer (a2) is not particularly limited, and known methods such as suspension polymerization, emulsion polymerization, solution polymerization, and bulk polymerization can be used. Among these, bulk polymerization and solution polymerization are preferred because they allow easy production of polymers and do not contain impurities such as emulsifiers.

[0024] (1-3-1) Solution polymerization The solution polymerization method includes a method in which the raw material monomers to be used are dissolved in an organic solvent, a thermal polymerization initiator is added, and the mixture is heated and stirred. When synthesis is performed by radical polymerization using the solution polymerization method, the raw material monomers to be used are dissolved in an organic solvent, a thermal radical polymerization initiator is added, and the mixture is heated and stirred to obtain the polymer. If necessary, a chain transfer agent can be used to adjust the molecular weight of the polymer.

[0025] Examples of organic solvents used in solution polymerization include ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; esters such as ethyl acetate and butyl acetate; ethers such as propylene glycol monomethyl ether; aromatic hydrocarbons such as toluene and xylene; and aliphatic hydrocarbons such as hexane, heptane, and mineral spirits.

[0026] Examples of the thermal polymerization initiator include azo-based initiators such as azobisisobutyronitrile, azobisisovaleronitrile, azobiscyclohexanecarbonitrile, and azobiscyanovaleric acid; organic peroxides such as t-butyl peroxypivalate, t-hexyl peroxypivalate, dilauroyl peroxide, di(2-ethylhexyl)peroxydicarbonate, di-t-butyl peroxide, and dicumyl peroxide; and hydrogen peroxide-iron(II) salt, peroxodisulfate-sodium hydrogensulfite, and cumene hydroperoxide-iron(II) salt. The proportion of the thermal polymerization initiator used may be appropriately set depending on the target molecular weight. The proportion of the thermal radical polymerization initiator used is preferably 0.1 to 10 parts by weight per 100 parts by weight of the total of all the monomers used.

[0027] (1-3-2) Bulk polymerization Examples of the bulk polymerization method include known methods disclosed in JP-A Nos. 57-502171, 59-6207, and 60-215007. For example, a method can be mentioned in which a pressurizable reactor is filled with a solvent, and the reactor is set at a predetermined temperature under pressure, and then a monomer mixture comprising each monomer and, if necessary, a polymerization solvent is fed to the reactor at a constant feed rate, and a polymerization liquid is withdrawn in an amount corresponding to the amount of the monomer mixture fed. If necessary, a polymerization initiator can be blended into the monomer mixture, and the blending amount, if any, is preferably 0.001 to 2 parts by weight per 100 parts by weight of the monomer mixture. The pressure depends on the reaction temperature and the boiling points of the monomer mixture and solvent used, and may be any pressure that does not affect the reaction but can maintain the desired reaction temperature. The residence time of the monomer mixture is preferably 1 to 60 minutes. If the residence time is less than 1 minute, the monomers may not react sufficiently, and if the residence time exceeds 60 minutes, productivity may decrease. The preferred residence time is 2 to 40 minutes.

[0028] Examples of polymerization initiators used to obtain copolymer (a1) include any initiator that generates radicals at a predetermined reaction temperature. Specific examples include organic peroxides such as di-t-butyl peroxide, di-t-hexyl peroxide, t-hexylperoxy-2-ethylhexanoate, t-butylperoxy-2-ethylhexanoate, cumene hydroperoxide, and t-butyl hydroperoxide, and azo compounds such as 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2-methylbutyronitrile), azobiscyclohexacarbonitrile, azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2-amidinopropane) dihydrochloride, and 4,4'-azobis(4-cyanovaleric acid). These polymerization initiators may be used alone or in combination.

[0029] The amount of the polymerization initiator used can be adjusted appropriately depending on the types of polymerization initiator and monomer, the desired molecular weight, polymerization conditions, etc., but is generally 0.001 to 10 parts by weight per 100 parts by weight of the monomer used.

[0030] When an organic solvent is used to produce the copolymer (a1), an organic hydrocarbon compound is suitable, and examples thereof include cyclic ethers such as tetrahydrofuran and dioxane, aromatic hydrocarbon compounds such as benzene, toluene and xylene, esters such as ethyl acetate and butyl acetate, ketones such as acetone, methyl ethyl ketone and cyclohexanone, and alcohols such as methanol, ethanol and isopropanol, and one or more of these can be used. Organic solvents that do not dissolve the (meth)acrylate copolymer well tend to cause scale growth on the walls of the reactor, which can lead to production problems during cleaning processes and the like.

[0031] The amount of organic solvent used is preferably 80 parts by weight or less relative to 100 parts by weight of the total vinyl monomers. By using 80 parts by weight or less, a high conversion rate can be obtained in a short time. More preferably, it is 1 to 50 parts by weight. In addition, a dehydrating agent such as trimethyl orthoacetate or trimethyl orthoformate can also be added. A known chain transfer agent may be used in the production of the copolymer (a1).

[0032] The reaction liquid withdrawn from the reactor can be directly used in the next step, or the polymer can be isolated by removing volatile components such as unreacted monomers, organic solvents, and low-molecular-weight oligomers by distillation, etc. A portion of the volatile components such as unreacted monomers, organic solvents, and low-molecular-weight oligomers distilled off from the reaction liquid can be returned to the raw material tank or directly to the reactor and reused in the polymerization reaction. Recycling the unreacted monomers and the organic solvent is an economically preferable method. When recycling, it is necessary to determine the mixing ratio of the newly fed monomer mixture so as to maintain the desired monomer ratio and the desired amount of organic solvent in the reactor.

[0033] (1-3-3) Physical properties of copolymer (a1) The weight-average molecular weight (hereinafter also referred to as "Mw") of copolymer (a1) is preferably 1,500 to 50,000, more preferably 1,500 to 40,000, even more preferably 2,000 to 30,000, even more preferably 2,500 to 25,000, and particularly preferably 3,000 to 15,000. By ensuring that Mw is 50,000 or less, the resulting component (A) can be made low-viscosity even at relatively high concentrations, improving coatability and compatibility when mixed with other curable resins. By ensuring that Mw is 1,500 or more, the resulting cured product of component (A) will have excellent weather resistance and tensile properties. In the present invention, Mw means a value obtained by converting the molecular weight measured by gel permeation chromatography (hereinafter referred to as GPC) into polystyrene equivalent.

[0034] The Tg (glass transition temperature) of copolymer (a1) is not particularly limited, but is usually from -40°C to 90°C, and preferably from 0°C to 90°C. A temperature of 0°C or higher results in excellent strength of the cured product, while a temperature of 90°C or lower results in excellent flexibility of the cured product. A temperature of 30 to 80°C is more preferred.

[0035] In the present invention, Tg is determined from the intersection of the baseline and the tangent at the inflection point of a heat flux curve obtained using a differential scanning calorimeter such as a TA Instruments (Q-100) etc. The heat flux curve is obtained by cooling approximately 10 mg of a sample to -100°C in a nitrogen atmosphere, holding it for 5 minutes, then heating it to 300°C at a rate of 10°C / min, further cooling it to -100°C, holding it for 5 minutes, and then heating it to 350°C at a rate of 10°C / min.

[0036] In the case of a typical solution polymerization method such as that disclosed in JP 2014-115538 A, the polymerization temperature is relatively low, and therefore the number of functional groups varies among polymer molecules due to the influence of the copolymerization reactivity ratio. On the other hand, in the case of high-temperature polymerization, the influence of the copolymerization reactivity ratio is reduced, and in the case of continuous polymerization, a constant polymer continues to be produced, so the variation in the number of functional groups among molecules becomes extremely small. Furthermore, when comparing conventional solution polymerization with high-temperature polymerization, when synthesizing a polymer of the same molecular weight, high-temperature polymerization requires less polymerization initiator and leaves less initiator residue, resulting in better weather resistance. In particular, in the case of electron beam curing, since no polymerization catalyst such as a photoinitiator is used in the curing reaction, the amount of initiator residue contained in the polymer has a significant effect on weather resistance. Therefore, the copolymer (a1) used in the present invention generally preferably has a terminal double bond concentration of 0.5 meq / g or less, more preferably 0.4 meq / g or less. When the terminal double bond concentration is 0.5 meq / g or less, a decrease in the curing rate can be suppressed. Furthermore, when a copolymer obtained by high-temperature continuous polymerization is used as the copolymer (a1) in the present invention, the terminal double bond concentration of the copolymer (a1) is preferably 0.02 meq / g or more and 0.5 meq / g or less. By having a terminal double bond concentration of 0.02 meq / g or more, rapid curing during curing is suppressed, and residual stress is less likely to remain, resulting in improved mechanical properties.

[0037] (2) Unsaturated oligomer (a2) The unsaturated oligomer (a2) is an oligomer containing an unsaturated double bond and having a Tg of -30 to -90°C. Here, the unsaturated double bond is preferably an ethylenically unsaturated group, and specific examples include a (meth)acryloyl group and a vinyl group, of which a (meth)acryloyl group is more preferred, and an acryloyl group is particularly preferred. In the present invention, the oligomer means a compound having a molecular weight of 250 or more and 2,000 or less. As described above, component (A) can be obtained by reacting the reactive group in copolymer (a1) obtained by the above polymerization method with the reactive group of unsaturated oligomer (a2). More specifically, it can be obtained by chemically bonding and adding unsaturated oligomer (a2) to copolymer (a1) having the reactive group via the reactive group.

[0038] When the copolymer (a1) is an epoxy polymer or a copolymer having a hydroxyl group as a reactive group, the unsaturated oligomer (a2) can be a compound having a carboxyl group or an isocyanate group as a functional group that reacts with the reactive group.

[0039] Examples of the unsaturated oligomer (a2) having a carboxyl group include an ε-caprolactone adduct of (meth)acrylic acid. ε-caprolactone adducts of acrylic acid are commercially available, and examples thereof include Aronix M-5300 (trade name, manufactured by Toagosei Co., Ltd., Tg=−78° C., polycaprolactone chain length≈2).

[0040] Examples of the unsaturated oligomer (a2) having an isocyanate group include urethane (meth)acrylates having an isocyanate group at one end. Urethane acrylates with an isocyanate group at one end can be prepared by reacting a diol with a diisocyanate to produce a compound with isocyanate groups at both ends, and then reacting this compound with a hydroxyl group-containing acrylate. Examples of diisocyanates include isophorone diisocyanate and hexamethylene diisocyanate, and examples of diols include polytetramethylene glycol. Examples of hydroxyl group-containing acrylates include 2-hydroxyethyl acrylate. Examples of methods for producing the compound include a method in which a diisocyanate and a diol are reacted in an organic solvent in the presence of a tin catalyst such as dioctyltin to obtain a urethane oligomer having isocyanate groups at both ends, and then a hydroxyl group-containing (meth)acrylate is reacted in the presence of a polymerization inhibitor.

[0041] When the copolymer (a1) is a copolymer having an isocyanate group or a carboxyl group as a reactive group, the unsaturated oligomer (a2) can be a compound having a hydroxyl group as a functional group that reacts with the reactive group. Examples of the unsaturated oligomer (a2) having a hydroxyl group include ε-caprolactone adducts of hydroxyalkyl (meth)acrylates such as ε-caprolactone adducts of 2-hydroxyethyl (meth)acrylate, polypropylene glycol adducts of (meth)acrylic acid, polyethylene glycol adducts of (meth)acrylic acid, poly(3-hydroxybutyrate) adducts of 2-hydroxyethyl (meth)acrylate, and polytetramethylene glycol adducts of (meth)acrylic acid. The ε-caprolactone adduct of 2-hydroxyethyl (meth)acrylate is commercially available, such as Plaxel FA2D (ε-caprolactone adduct of 2-hydroxyethyl acrylate, Daicel Corporation). Manufacturer Product name, same as below. Molecular weight 344, Tg=- 40 °C), FA5 (an adduct of 2-hydroxyethyl acrylate and ε-caprolactone, molecular weight 689), FM2D (an adduct of 2-hydroxyethyl methacrylate and ε-caprolactone, molecular weight 358), FM3 (an adduct of 2-hydroxyethyl methacrylate and ε-caprolactone, molecular weight 473), and FM5 (an adduct of 2-hydroxyethyl methacrylate and ε-caprolactone, molecular weight 701). An example of a polypropylene glycol adduct of acrylic acid is a compound having a Tg of -75°C, an example of a polyethylene glycol adduct of acrylic acid is a compound having a Tg of -41°C, an example of a poly(3-hydroxybutyrate) adduct of 2-hydroxyethyl acrylate is a compound having a Tg of -40°C, and an example of a polytetramethylene glycol adduct of acrylic acid is a compound having a Tg of -84°C.

[0042] The unsaturated oligomer (a2) is preferably a compound containing a ring-opened caprolactone structure. The composition containing component (A) obtained using such a compound is preferred in that the cured product has excellent elongation. Specific examples of the compound include the compounds listed above. Examples of the unsaturated oligomer (a2) having a carboxyl group include an ε-caprolactone adduct of (meth)acrylic acid. Examples of the unsaturated oligomer (a2) having a hydroxyl group include ε-caprolactone adducts of hydroxyalkyl (meth)acrylates, such as ε-caprolactone adducts of 2-hydroxyethyl (meth)acrylate.

[0043] (3) Manufacturing method of component (A) The component (A) is preferably produced by reacting a reactive group of the copolymer (a1) with a group in the unsaturated oligomer (a2) that is reactive with the reactive group. That is, examples of the reaction for adding an unsaturated oligomer (a2) to a copolymer (a1) include a method of reacting a copolymer (a1) having an epoxy group or a hydroxyl group as a reactive group with an unsaturated oligomer (a2) having a carboxyl group, and a method of reacting a copolymer (a1) having an isocyanate group or a carboxyl group as a reactive group with an unsaturated oligomer (a2) having a hydroxyl group. Among these, the method of reacting a copolymer (a1) having an epoxy group as a reactive group with an unsaturated oligomer (a2) having a carboxyl group is preferred.

[0044] The reaction ratio of the copolymer (a1) and the unsaturated oligomer (a2) may be appropriately set depending on the type of component (A) to be produced. The amount of the reactive group contained in the unsaturated oligomer (a2) is preferably 0.5 to 1.5 mol, more preferably 0.8 to 1.2 mol, and even more preferably 0.9 to 1.1 mol, per 1 mol of the reactive group contained in the copolymer (a1).

[0045] As a method for reacting and adding the unsaturated oligomer (a2) having a carboxyl group to the copolymer (a1) having an epoxy group, there can be mentioned a method in which the copolymer (a1) having an epoxy group, the unsaturated oligomer (a2) having a carboxyl group, a catalyst, and an organic solvent are mixed and heated to 60 to 120°C for about 5 to 30 hours.

[0046] The reaction ratio of the copolymer (a1) having an epoxy group and the unsaturated oligomer (a2) having a carboxyl group is preferably 0.5 to 1.5 moles, more preferably 0.8 to 1.2 moles, and even more preferably 0.9 to 1.1 moles of carboxyl groups in the unsaturated oligomer (a2) having a carboxyl group per mole of epoxy groups in the copolymer (a1) having an epoxy group.

[0047] Examples of catalysts include tetrabutylammonium bromide, tetrabutylammonium chloride, tetramethylammonium bromide, tetramethylammonium chloride, triphenylphosphine, tributylphosphine, 1,8-diazabicyclo[5,4,0]-7-undecene, and 1,4-diazabicyclo[2,2,2]octane. Of these, triphenylphosphine is preferred because it causes less discoloration of the cured product after a heat resistance test.

[0048] The amount of catalyst added is preferably about 0.5 to 5% by weight based on the total amount of the copolymer (a1) having an epoxy group and the unsaturated oligomer (a2) having a carboxyl group.

[0049] Examples of the organic solvent include ethyl acetate, butyl acetate, acetone, methyl ethyl ketone, etc. When the copolymer (a1) having an epoxy group is in a liquid state, the modification reaction can be carried out without adding an organic solvent.

[0050] A typical method for reacting the hydroxyl-containing copolymer (a1) with the carboxyl-containing unsaturated oligomer (a2) is a dehydration esterification method, which involves heating a mixture of the hydroxyl-containing copolymer (a1), the carboxyl-containing unsaturated oligomer (a2), a catalyst, and a solvent at 100 to 120°C, and azeotropically dehydrating the organic solvent and the resulting water to allow the reaction to proceed.

[0051] Examples of the catalyst include p-toluenesulfonic acid, methanesulfonic acid, trifluoromethanesulfonic acid, and sulfuric acid, and the amount of the catalyst used is 0.05 to 5 mol % based on the number of moles of hydroxyl groups to be reacted.

[0052] The organic solvent used is preferably one that has low solubility in the water produced in the dehydration esterification reaction and allows the reaction to proceed while distilling off the water as an azeotrope. Preferred organic solvents include, for example, aromatic hydrocarbons such as toluene, benzene, and xylene; aliphatic hydrocarbons such as hexane, cyclohexane, and heptane; and ketones such as methyl ethyl ketone and cyclohexanone. The proportion of the solvent is preferably 30 to 70% by weight based on the total amount of the reaction solution.

[0053] After the reaction, the acid is generally removed with water or an aqueous alkaline solution.

[0054] As a method of reacting and adding the unsaturated oligomer (a2) having a hydroxyl group to the copolymer (a1) having an isocyanate group, there can be mentioned a method in which the copolymer (a1) having an isocyanate group and the unsaturated oligomer (a2) having a hydroxyl group are mixed, and then a curing catalyst such as dibutyltin dilaurate is added as necessary, and the mixture is heated to 60 to 100°C.

[0055] Examples of a method for reacting and adding an unsaturated oligomer (a2) having a hydroxyl group to a copolymer (a1) having a carboxyl group include a method in which the copolymer (a1) and the unsaturated oligomer (a2) having a hydroxyl group are mixed, and then a catalyst such as sulfuric acid, methanesulfonic acid, p-toluenesulfonic acid, sulfonated polystyrene, or Nafion-H is added, and the mixture is heated to 80 to 120°C, optionally in the presence of an organic solvent such as toluene, to proceed with the esterification reaction while distilling off the water produced. Furthermore, the catalyst remaining after the reaction can be removed by one or a combination of two or more of the following methods: washing with water, alkali neutralization, ion exchange resin, chemical filter for catalyst removal, and filtration.

[0056] In any of the above modification methods, it is preferable to add a polymerization inhibitor to suppress gelation or to improve the storage stability of the modified product. Examples of the polymerization inhibitor include methoxyphenol, hydroquinone, dibutylhydroxytoluene, etc. From the viewpoint of suppressing coloration of the cured product, it is particularly preferable to use dibutylhydroxytoluene.

[0057] (4) Physical properties of component (A) (acrylic equivalent and molecular weight) The acrylic equivalent of component (A) is preferably 3000 g / eq or less. More preferred ranges of the acrylic equivalent of component (A) are, in order, 150 g / eq to 2500 g / eq, 300 g / eq to 2000 g / eq, 400 g / eq to 1400 g / eq, and 700 g / eq to 1000 g / eq. By ensuring that the acrylic equivalent is 150 g / eq or more, the elongation and flexibility of the cured product can be ensured, and by ensuring that the acrylic equivalent is 3000 g / eq or less, the strength and weather resistance of the cured product can be ensured and a good curing rate can be maintained.

[0058] In the present invention, the acrylic equivalent (g / eq) represents the weight (g) per equivalent (eq) of (meth)acryloyl groups, and the larger the value, the lower the concentration of (meth)acryloyl groups, and the smaller the value, the higher the concentration of (meth)acryloyl groups.

[0059] The acrylic equivalent can be calculated using the following formula: In the formula, the number of moles of (meth)acryloyl groups in component (A) is the number of moles of (meth)acryloyl groups in the unsaturated oligomer (a2) added to the copolymer (a1) in the modification reaction, and does not include (meth)acryloyl groups derived from unreacted unsaturated oligomer (a2) present after the modification reaction.

[0060]

number

[0061] The molecular weight, Mw, of the component (A) is preferably from 2,000 to 60,000, and more preferably from 2,000 to 50,000. A Mw of 2,000 or more provides a cured product with excellent weather resistance and tensile properties, while a Mw of 60,000 or less allows for low viscosity even at relatively high concentrations, resulting in excellent coatability and excellent compatibility when mixed with other curable compounds.More preferred ranges of Mw for component (A) are 3,000 to 50,000, 3,000 to 40,000, 3,000 to 30,000, and 4,000 to 20,000, in order of preference. The number average molecular weight (hereinafter referred to as "Mn") of component (A) is preferably 1,000 to 30,000. A Mn of 1,000 or more provides a cured product with excellent weather resistance and tensile properties, while a Mn of 30,000 or less allows for low viscosity even at relatively high concentrations, resulting in excellent coatability and excellent compatibility when mixed with other curable compounds. More preferred ranges for Mn of component (A) are 1,500 to 15,000, 2,000 to 10,000, and 2,500 to 7,000, in order of preference. In the present invention, Mn means a value obtained by converting the molecular weight measured by GPC into polystyrene equivalent.

[0062] 2. Component (B) The component (B) is an isocyanate compound. The component (B) is not particularly limited as long as it is a compound having an isocyanate group (-N=C=O), and examples thereof include aromatic isocyanates, aliphatic isocyanates, alicyclic isocyanates, and modified isocyanates thereof.

[0063] Examples of aromatic isocyanates include diphenylmethane diisocyanate (MDI), crude diphenylmethane diisocyanate, tolylene diisocyanate, naphthalene diisocyanate (NDI), p-phenylene diisocyanate (PPDI), xylene diisocyanate (XDI), tetramethylxylylene diisocyanate (TMXDI), and tolidine diisocyanate (TODI). Examples of the aliphatic isocyanate include hexamethylene diisocyanate (HDI), lysine diisocyanate (LDI), and lysine triisocyanate (LTI). Examples of alicyclic isocyanates include isophorone diisocyanate (IPDI), cyclohexyl diisocyanate (CHDI), hydrogenated XDI (H6XDI), and hydrogenated MDI (H12MDI). Examples of modified isocyanates include urethane-modified, dimer-, trimer-, carbodiimide-modified, allophanate-modified, biuret-modified, urea-modified, isocyanurate-modified, oxazolidone-modified, and isocyanate-terminated prepolymers of the above-mentioned isocyanate compounds. Of these compounds, aliphatic isocyanates and alicyclic isocyanates are preferred as component (B) because they provide a cured product with excellent weather resistance.

[0064] 3. Active energy ray curable composition The present invention relates to an active energy ray-curable composition containing components (A) and (B). The composition can be produced by stirring and mixing components (A) and (B), and, if necessary, other components described below.

[0065] The ratio of component (A) to component (B) is preferably 0.5 to 1.5 equivalents, more preferably 0.8 to 1.2, of component (B) per equivalent of hydroxyl groups contained in component (A).

[0066] The viscosity of the composition may be appropriately set depending on the application and purpose of use, etc. The viscosity is preferably 100 to 20,000 mPa·s, and more preferably 200 to 8,000 mPa·s. In the present invention, the viscosity refers to a value measured at 25°C using an E-type viscometer (cone-plate type viscometer).

[0067] The composition of the present invention exhibits the effect that the cured product thereof has excellent tensile properties such as tensile strength and elongation, heat resistance, and weather resistance. In terms of tensile properties, the breaking strength is preferably 20 MPa or more, more preferably 30 MPa or more. Next, the elongation is preferably 5% or more. The tensile product is preferably 150 MPa or more, more preferably 200 MPa or more. Since breaking strength and elongation are generally in a trade-off relationship, the higher the tensile product (breaking strength × elongation / 2), the better the tensile properties.

[0068] The composition of the present invention essentially comprises the above-mentioned components (A) and (B), but may also contain various other components as required. Preferred other components include an organic solvent (C) [hereinafter also referred to as "component (C)"], an ethylenically unsaturated compound (D) other than component (A) [hereinafter also referred to as "component (D)"], and a photoradical polymerization initiator [hereinafter also referred to as "component (E)"]. Components (C) to (E) and other components will be described below. In the following, components (A) and (D) are referred to as "curable components."

[0069] (1) Component (C) The composition of the present invention may contain an organic solvent as component (C) for the purpose of improving the coating properties on the substrate. Even if the organic solvent is the same compound, it is referred to as an "organic solvent" when used in a reaction system, and as an "organic solvent" when used in a composition such as a paint; in the present invention, these are collectively referred to as "organic solvent."

[0070] Specific examples of component (C) include hydrocarbon solvents such as n-hexane, benzene, toluene, xylene, ethylbenzene, and cyclohexane; alcoholic solvents such as methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutyl alcohol, 2-methoxyethanol, 2-ethoxyethanol, 2-(methoxymethoxy)ethanol, 2-isopropoxyethanol, 2-butoxyethanol, 2-isopentyloxyethanol, 2-hexyloxyethanol, 2-phenoxyethanol, 2-benzyloxyethanol, furfuryl alcohol, tetrahydrofurfuryl alcohol, diethylene glycol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, and propylene glycol monomethyl ether; ether solvents such as tetrahydrofuran, dioxane, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, bis(2-methoxyethyl) ether, bis(2-ethoxyethyl) ether, and bis(2-butoxyethyl) ether; ketone solvents such as acetone, methyl ethyl ketone, methyl-n-propyl ketone, diethyl ketone, butyl methyl ketone, methyl isobutyl ketone, methyl pentyl ketone, di-n-propyl ketone, diisobutyl ketone, phorone, isophorone, cyclopentanone, cyclohexanone, and methylcyclohexanone; ester solvents such as ethyl acetate, butyl acetate, isobutyl acetate, methyl glycol acetate, propylene glycol monomethyl ether acetate, and cellosolve acetate; Examples of the aprotic polar solvent include N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, N-methyl-2-pyrrolidone, and γ-butyrolactone.

[0071] As the component (C), one or more of the above-mentioned compounds can be used. Component (C) may be added separately to dilute component (A), or the organic solvent used in the production of component (A) may be used directly without separation.

[0072] The blending ratio of component (C) may be set appropriately taking into consideration the viscosity of the composition, the intended use, etc., but when component (D) described below is blended with 100 parts by weight of the total of components (A), (B), and (C), the blending ratio is preferably 70 parts by weight or less, more preferably 60 parts by weight or less, even more preferably 50 parts by weight or less, even more preferably 40 parts by weight or less, and particularly preferably 15 to 40 parts by weight, per 100 parts by weight of the total of components (A), (B), (C), and (D).

[0073] (2) Component (D) The composition of the present invention may contain, as necessary, component (D) [an ethylenically unsaturated compound other than component (A)] for the purposes of reducing the viscosity of the entire composition or adjusting other physical properties.

[0074] Specific examples of the (D) component include the monomer (a1-1), the monomer (a1-2), (meth)acrylates other than the monomers (a1-1) and (a1-2) (hereinafter referred to as "other (meth)acrylates"), and N-vinyl-2-pyrrolidone.

[0075] Other (meth)acrylates include compounds having one (meth)acryloyl group (hereinafter referred to as "monofunctional (meth)acrylates") and compounds having two or more (meth)acryloyl groups (hereinafter referred to as "polyfunctional (meth)acrylates").

[0076] Specific examples of monofunctional (meth)acrylates include trimethylcyclohexyl (meth)acrylate, 1-adamantyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, benzyl (meth)acrylate, allyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, phenoxyethyl (meth)acrylate, o-phenylphenol EO-modified (n=1 to 4) (meth)acrylate, p-cumylphenol EO-modified (n=1 to 4) (meth)acrylate, phenyl (meth)acrylate, o-phenylphenyl (meth)acrylate, p-cumylphenyl (meth)acrylate, N-(meth)acryloylmorpholine, N-vinylformamide, N-(meth)acryloyloxyethyl hexahydrophthalimide, and N-(meth)acryloyloxyethyl tetrahydrophthalimide.

[0077] Specific examples of polyfunctional (meth)acrylates include urethane (meth)acrylates such as urethane acrylates having a polyester skeleton and urethane (meth)acrylates such as urethane acrylates having a polycarbonate skeleton; Di(meth)acrylates having a bisphenol skeleton, such as bisphenol A EO-modified (n=1 to 2) di(meth)acrylate and bisphenol A di(meth)acrylate; (Poly)alkylene glycol di(meth)acrylates such as ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, polyethylene glycol (n=5 to 14) di(meth)acrylate, propylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, tetrapropylene glycol di(meth)acrylate, polypropylene glycol (n=5 to 14) di(meth)acrylate, 1,3-butylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, polybutylene glycol (n=3 to 16) di(meth)acrylate, and poly(1-methylbutylene glycol) (n=5 to 20) di(meth)acrylate Di(meth)acrylates of aliphatic diols such as 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, and neopentyl glycol di(meth)acrylate; Hydroxypivalic acid neopentyl glycol di(meth)acrylate; Di(meth)acrylates having an alicyclic skeleton, such as tricyclodecanedimethylol di(meth)acrylate; (Meth)acrylates with an isocyanurate skeleton, such as EO-modified isocyanuric acid diacrylate and ε-caprolactone-modified tris((meth)acryloxyethyl)isocyanurate Polyol poly(meth)acrylates such as glycerin tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri- or tetra(meth)acrylate, ditrimethylolpropane tri- or tetra(meth)acrylate, diglycerin tri- or tetra(meth)acrylate, and dipentaerythritol tri-, tetra-, penta-, or hexa(meth)acrylate; and Examples thereof include poly(meth)acrylates of polyol alkylene oxide adducts such as tri(meth)acrylates of glycerin alkylene oxide adducts, tri- or tetra(meth)acrylates of pentaerythritol alkylene oxide adducts, tri- or tetra(meth)acrylates of ditrimethylolpropane alkylene oxide adducts, tri- or tetra(meth)acrylates of diglycerin alkylene oxide adducts, and tri-, tetra-, penta-, or hexa(meth)acrylates of dipentaerythritol alkylene oxide adducts. In the above, EO-modified means ethylene oxide-modified, and n means the number of repeating alkylene oxide units. Among these compounds, the polyfunctional (meth)acrylate is preferably a urethane (meth)acrylate or a (meth)acrylate having an isocyanate skeleton.

[0078] As the component (D), the above-mentioned compounds may be used alone or in combination of two or more.

[0079] The amount of component (D) to be added may be set appropriately depending on the purpose, as long as it does not reduce the flexibility of the resulting cured product. However, it is preferably 1 to 70 parts by weight, more preferably 1 to 50 parts by weight, and even more preferably 1 to 25 parts by weight per 100 parts by weight of component (A).

[0080] (3) Component (E) When ultraviolet light and visible light are used as the active energy rays, the composition of the present invention may contain component (E) (photopolymerization initiator). When electron beams are used as the active energy rays, it is not always necessary to incorporate component (E), but a small amount of component (E) can be incorporated as needed to improve curability.

[0081] Component (E) includes benzil dimethyl ketal, benzil, benzoin, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one, oligo[2-hydroxy-2-methyl-1-[4-1-(methylvinyl)phenyl]propanone, 2-hydroxy-1-[4-[4-(2-hydroxy-2-methyl- aromatic ketone compounds such as 2-methyl-1-[4-(methylthio)]phenyl]-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butan-1-one, 2-dimethylamino-2-(4-methylbenzyl)-1-(4-morpholin-4-ylphenyl)butan-1-one, ADEKA Optomer N-1414 (manufactured by ADEKA Corporation), phenylglyoxylic acid methyl ester, ethyl anthraquinone, and phenanthrenequinone; benzophenone compounds such as benzophenone, 2-methylbenzophenone, 3-methylbenzophenone, 4-methylbenzophenone, 2,4,6-trimethylbenzophenone, 4-phenylbenzophenone, 4-(methylphenylthio)phenylphenylmethane, methyl-2-benzophenone, 1-[4-(4-benzoylphenylsulfanyl)phenyl]-2-methyl-2-(4-methylphenylsulfonyl)propan-1-one, 4,4'-bis(dimethylamino)benzophenone, 4,4'-bis(diethylamino)benzophenone, N,N'-tetramethyl-4,4'-diaminobenzophenone, N,N'-tetraethyl-4,4'-diaminobenzophenone, and 4-methoxy-4'-dimethylaminobenzophenone; Bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, ethyl-(2,4,6-trimethylbenzoyl)phenylphosphinate and bis(2,6-dimethoxybenzo) acylphosphine oxide compounds such as (methyl)-2,4,4-trimethylpentylphosphine oxide; Thioxanthone compounds such as thioxanthone, 2-chlorothioxanthone, 2,4-diethylthioxanthone, isopropylthioxanthone, 1-chloro-4-propylthioxanthone, 3-[3,4-dimethyl-9-oxo-9H-thioxanthone-2-yl]oxy]-2-hydroxypropyl-N,N,N-trimethylammonium chloride, and fluorothioxanthone; acridone compounds such as acridone and 10-butyl-2-chloroacridone; Oxime esters such as 1,2-octanedione 1-[4-(phenylthio)-2-(O-benzoyloxime)] and ethanone 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-1-(O-acetyloxime); 2,4,5-triarylimidazole dimers such as 2-(o-chlorophenyl)-4,5-diphenylimidazole dimer, 2-(o-chlorophenyl)-4,5-di(m-methoxyphenyl)imidazole dimer, 2-(o-fluorophenyl)-4,5-phenylimidazole dimer, 2-(o-methoxyphenyl)-4,5-diphenylimidazole dimer, 2-(p-methoxyphenyl)-4,5-diphenylimidazole dimer, 2,4-di(p-methoxyphenyl)-5-phenylimidazole dimer and 2-(2,4-dimethoxyphenyl)-4,5-diphenylimidazole dimer; and Examples include acridine derivatives such as 9-phenylacridine and 1,7-bis(9,9'-acridinyl)heptane.

[0082] These compounds can be used alone or in combination of two or more.

[0083] The blending ratio of component (E) is preferably 0.01 to 10 parts by weight, more preferably 0.1 to 5 parts by weight, per 100 parts by weight of component (A) combined with component (D) when component (D) is included. By setting the blending ratio of component (E) to 0.01 parts by weight or more, the composition can be cured with an appropriate amount of ultraviolet or visible light, improving productivity, while by setting the blending ratio to 10 parts by weight or less, the cured product can be made to have excellent weather resistance and transparency.

[0084] (4) Other components other than the above As other components other than those mentioned above, various components can be blended depending on the purpose. When the composition of the present invention is used as a coating agent, examples of additives that can be used include polymerization inhibitors and / or antioxidants, light resistance improvers, inorganic particles, surface modifiers, pigments, dyes, and tackifiers. Among the other components, the polymerization inhibitor and / or antioxidant, and the light resistance improver will be described below.

[0085] <Polymerization inhibitor or / and antioxidant> The active energy ray-curable composition of the present invention may contain a polymerization inhibitor and / or an antioxidant in order to improve storage stability. The polymerization inhibitor is preferably hydroquinone, hydroquinone monomethyl ether, 2,6-di-tert-butyl-4-methylphenol, or various phenol-based antioxidants, but may also be a sulfur-based secondary antioxidant, a phosphorus-based secondary antioxidant, or the like.

[0086] The total amount of these polymerization inhibitors and / or antioxidants blended is preferably 0.001 to 3 parts by weight, and more preferably 0.01 to 0.5 parts by weight, per 100 parts by weight of the combined amount of components (A) and (D) when component (D) is included, per 100 parts by weight of component (A).

[0087] <Light resistance improver> The active energy ray-curable composition of the present invention may contain a light resistance improver such as an ultraviolet absorber or a light stabilizer.

[0088] Examples of ultraviolet absorbers include benzotriazole compounds such as 2-(2'-hydroxy-5-methylphenyl)benzotriazole, 2-(2'-hydroxy-3',5'-di-t-butylphenyl)benzotriazole, and 2-(2'-hydroxy-3'-t-butyl-5'-methylphenyl)benzotriazole; Triazine compounds such as 2,4-bis(2,4-dimethylphenyl)-6-(2-hydroxy-4-isooctyloxyphenyl)-s-triazine; Examples of the benzophenone compounds include 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxy-benzophenone, 2-hydroxy-4-methoxy-4'-methylbenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2,4,4'-trihydroxybenzophenone, 2,2',4,4'-tetrahydroxybenzophenone, 2,3,4,4'-tetrahydroxybenzophenone, 2,3',4,4'-tetrahydroxybenzophenone, and 2,2'-dihydroxy-4,4'-dimethoxybenzophenone.

[0089] Examples of light stabilizers include low molecular weight hindered amine compounds such as N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)-N,N'-diformylhexamethylenediamine, bis(1,2,6,6-)pentamethyl-4-piperidyl)-2-(3,5-ditertiarybutyl-4-hydroxybenzyl)-2-n-butylmalonate, and bis(1,2,2,6,6-pentamethyl-4-piperidinyl)sebacate; Examples of the hindered amine light stabilizer include high molecular weight hindered amine compounds such as 2,6,6-tetramethyl-4-piperidyl)-N,N'-diformylhexamethylenediamine and bis(1,2,2,6,6-pentamethyl-4-piperidinyl)sebacate.

[0090] The amount of the light resistance improver to be added is preferably 0 to 5 parts by weight, more preferably 0 to 1 part by weight, per 100 parts by weight of the component (A), and more preferably 0 to 1 part by weight, if the component (D) is included, per 100 parts by weight of the total amount of the components (A) and (D).

[0091] 4. Usage method The active energy ray-curable composition of the present invention can be used in various ways depending on the purpose. For example, when the composition of the present invention is used as a coating agent, the composition is applied to a substrate, and if an organic solvent is contained in the composition, the organic solvent in the composition is evaporated by heating, and then the composition is cured by irradiating with active energy rays. Furthermore, when the composition of the present invention is used as an adhesive, a method can be used in which the composition is applied to a substrate, and if an organic solvent is contained in the composition, the organic solvent in the composition is evaporated by heating, and then the composition is bonded to another substrate, and then further cured by irradiation with active energy rays.

[0092] The composition of the present invention can be applied to a variety of substrates, including inorganic materials, plastics, and paper. Inorganic materials include glass, metal, mortar, concrete, and stone. Metals include steel sheets, aluminum, chromium, zinc oxide (ZnO), and indium oxide. Examples include metal oxides such as indium tin (ITO). Specific examples of plastics include polyolefins such as polyethylene and polypropylene, ABS resin, polyvinyl alcohol, cellulose acetate resins such as triacetyl cellulose and diacetyl cellulose, acrylic resin, polyethylene terephthalate (hereinafter referred to as "PET resin"), polycarbonate, polyarylate, polyethersulfone, cyclic polyolefin resins containing cyclic olefins as monomers such as norbornene, polyvinyl chloride, epoxy resin, polyurethane resin, etc. Thermoplastic plastics are preferred, and specific examples thereof include PET resin, acrylic resin, ABS resin, polycarbonate, polypropylene, polyethylene, etc., with PET resin being preferred. Of these materials, metals and plastics are preferred as the substrate. The shape of the substrate is not particularly limited, and may be any of a sheet, a film, a plate, and the like.

[0093] The method for applying the composition may be appropriately determined depending on the purpose, and examples thereof include coating methods using conventionally known bar coaters, applicators, doctor blades, knife coaters, comma coaters, reverse roll coaters, die coaters, lip coaters, gravure coaters, and microgravure coaters.

[0094] When the composition of the present invention contains an organic solvent, it is preferable that after coating on a substrate, the composition be heated and dried to evaporate the organic solvent. The drying temperature is not particularly limited as long as it is a temperature below which the substrate to be applied does not suffer from problems such as deformation. A preferred heating temperature is 40 to 100° C. The drying time may be appropriately set depending on the substrate to be applied and the heating temperature, and is preferably 0.5 to 20 minutes.

[0095] The thickness of the cured film of the composition on the substrate may be appropriately set depending on the purpose. The thickness of the cured film may be selected depending on the substrate to be used and the application of the substrate having the produced cured film, but is preferably 1 to 100 μm, more preferably 2 to 40 μm.

[0096] Examples of the active energy ray used to cure the active energy ray-curable composition of the present invention include electron beams, ultraviolet rays, and visible light. Of these, ultraviolet light is preferred because it can be cured using a relatively simple device and can be cured in a short time with low energy irradiation. Electron beam irradiation is preferred because it does not necessarily require the addition of component (E) (photopolymerization initiator) and the cured product has excellent heat resistance and weather resistance. Examples of ultraviolet irradiation devices include high-pressure mercury lamps, metal halide lamps, ultraviolet (UV) electrodeless lamps, and light-emitting diodes (LEDs).

[0097] The irradiation conditions for the active energy ray irradiation, such as the dose, irradiation amount, and irradiation intensity, may be appropriately selected depending on the composition used, the substrate, the purpose, and the like. As an example of using ultraviolet light, when using a high-pressure mercury lamp, the irradiation energy in the UV-A region is 100 to 8,000 mJ / cm 2 is preferred, and 200 to 3,000 mJ / cm 2 is more preferred. When an electron beam is used, it is preferable to irradiate at an acceleration voltage of 50 to 300 kV and with an absorbed dose of 10 to 1,000 kGy.

[0098] The composition of the present invention can be used in a variety of applications. Specific examples thereof include coating agents, adhesives, inks, and films, and the material can be preferably used as a coating agent. Specific applications of the coating agent include various paints, and top coating agents for decorative films and vehicle exterior parts. [Example]

[0099] The present invention will be described in more detail below with reference to examples and comparative examples. In the following, "parts" means parts by weight. In the Production Examples and Working Examples, the molecular weight, Tg, acid value, solid content, viscosity, and terminal double bond concentration were measured according to the following methods.

[0100] <Molecular weight measurement> Using a gel permeation chromatograph (model HLC-8320, manufactured by Tosoh Corporation), polystyrene-equivalent Mw (weight average molecular weight) and Mn (number average molecular weight) were obtained under the following conditions. Measurement conditions Column: Tosoh Corporation TSKgel SuperMultiporeHZ-M x 4 Column temperature: 40℃ Eluent: tetrahydrofuran Detector: RI

[0101] <Measurement of Tg> The Tg of the copolymer (a1) was measured by a differential scanning calorimeter (DSC) under the following conditions. Measurement conditions DSC: TA Instrument (Q-100) Temperature rise: 10°C / min Measurement atmosphere: Nitrogen

[0102] <Measurement of acid value> The acid value measurement was carried out in accordance with JIS K0070. Specifically, a sample was weighed so that the titration volume was approximately 10 mL, and diluted with approximately 50 mL of tetrahydrofuran. Then, titration was carried out using an automatic titrator COM-1600ST (manufactured by Hiranuma Sangyo Co., Ltd.) with a 0.1 N KOH / ethanol solution as the titrant.

[0103] <Solid content> The solid content was determined from the weight loss after drying in a forced air dryer at 150°C for 1 hour. The solid content was adjusted to achieve an easy-to-coat viscosity (1,000-4,000 mPa·s), so a high solid content means that less organic solvent is used, which is advantageous.

[0104] <Viscosity at 25°C with a solid content of 60%> The solid content of each sample was adjusted to 60% by diluting it with an organic solvent (butyl acetate or toluene) or by removing the organic solvent using an evaporator.The E-type viscosity of each sample was measured using a TVE-20H viscometer (cone / plate type, manufactured by Toki Sangyo Co., Ltd.) under the following conditions. Measurement conditions Cone shape: angle 1°34′, radius 24 mm (less than 10,000 mPa·s) Angle 3°, radius 7.7mm (10,000mPa s or more) Temperature: 25℃±0.5℃

[0105] <Terminal double bond concentration> 1By H-NMR measurement, the double bond concentration per weight of the polymer was calculated from the ratio of the integral value of the signal derived from hydrogen bonded to the double bond near 5.5 ppm to the integral value of the signal derived from hydrogen bonded to the carbon adjacent to the ester group at 3.0 to 4.5 ppm, as well as the monomer composition ratio of the polymer.

[0106] 1. Production example (1) Production example 1 The temperature of a 1000 mL oil-jacketed pressurized stirred tank reactor was maintained at 263°C. Next, while maintaining the pressure of the reactor constant, a monomer mixture consisting of 70 parts of methyl methacrylate (hereinafter referred to as "MMA"), 10 parts of ethyl acrylate (hereinafter referred to as "EA"), 20 parts of glycidyl methacrylate (hereinafter referred to as "GMA"), 12 parts of methyl ethyl ketone (hereinafter referred to as "MEK") as a solvent, 3 parts of trimethyl orthoacetate (manufactured by Nippoh Chemical Industries, Ltd., trade name "MOA", hereinafter referred to as "MOA"), and 1 part of di-t-hexyl peroxide (manufactured by NOF Corp., trade name "Perhexyl D", hereinafter referred to as "DTHP") as a polymerization initiator was continuously fed from a raw material tank to the reactor at a constant feed rate (48 g / min, residence time: 12 min), and a reaction liquid equivalent to the amount of the monomer mixture fed was continuously withdrawn from the outlet. Immediately after the start of the reaction, the reaction temperature dropped once, and then a temperature rise due to the heat of polymerization was observed, but the reaction temperature was maintained at 187 to 189°C by controlling the temperature of the oil jacket.

[0107] The point at which the temperature stabilized after the start of the monomer mixture supply was designated the start point for collecting the reaction solution, and the reaction was continued for 37 minutes from this point. As a result, 1.78 kg of the monomer mixture was supplied and 1.78 kg of the reaction solution was collected. The reaction solution was then introduced into a thin-film evaporator, and volatile components such as unreacted monomers were separated, yielding 1.08 kg of a (meth)acrylate polymer having an epoxy group (hereinafter referred to as "copolymer a1-1"). Table 1 shows the polystyrene-equivalent Mw, Tg, and terminal double bond concentration (meq / g) of copolymer a1-1.

[0108] Next, copolymer a1-1 (100 parts), dibutylhydroxytoluene (hereinafter referred to as "BHT") (0.15 parts) as a polymerization inhibitor, M-5300 (45.7 parts, corresponding to an acid value of 1.1 equivalents of the epoxy group of polymer a1-1), and butyl acetate (62.7 parts) as an organic solvent were placed in a 1 L flask, and the liquid temperature was raised to 95°C while bubbling a 5% oxygen-nitrogen mixed gas, to dissolve copolymer a1-1. After uniform dissolution, triphenylphosphine (hereinafter referred to as "TPP") (0.73 parts) was added as a reaction catalyst, and the mixture was stirred for 12 hours while maintaining the internal temperature at 95°C. Further TPP (0.73 parts) was added, and the reaction was continued for 12 hours. Thereafter, the acid value was measured, and it was confirmed to be 4.5 mgKOH / g, and the reaction was terminated. As a result, polymer A-1 was obtained, which was an M-5300 adduct (acrylate modified product) of copolymer a1-1.

[0109] Table 2 shows the solid content, acid value, Mn, Mw, acrylic equivalent (g / eq) calculated as polystyrene, and viscosity at 25° C. with a solid content of 60% of Polymer A-1.

[0110] (2) Production examples 2 to 11 Polymers A-2 to A-11 were obtained in the same manner as in Production Example 1, except for the changes shown in Tables 1 and 2. The physical properties of the obtained copolymers (a1) and component (A) are shown in Tables 1 and 2.

[0111] (3) Production example 12 Copolymer a1-12 was obtained by the same procedure as in Production Example 1, except for the changes shown in Tables 1 and 2. A 1 L reactor equipped with a stirrer, a thermometer, and a water separator was charged with copolymer a1-12 (100 parts), M-5300 (63.2 parts, corresponding to an acid value of 1.0 equivalent of the hydroxyl groups of polymer a1-12), toluene (71.0 parts) as a solvent, p-toluenesulfonic acid (1.6 parts) as a catalyst, and dibutylhydroxytoluene (hereinafter referred to as "BHT") (0.16 parts) as a polymerization inhibitor, and the mixture was refluxed at 80 kPa (absolute pressure) for 6 hours to distill off water (3.7 parts), thereby carrying out a dehydration esterification reaction. Then, 10% aqueous sodium hydroxide solution (50 parts) was added to the reaction solution, stirred, and then allowed to stand, and the lower layer (aqueous layer) was separated and removed. Next, water (50 parts) was added to the upper layer (organic layer), stirred, allowed to stand, and the lower layer (aqueous layer) was removed. BHT (0.16 parts) was added to the upper layer (organic layer) and dissolved, and then sodium sulfate was added to dehydrate, and the supernatant was removed. As a result, polymer A-12, which was an M-5300 adduct (acrylate modified product) of copolymer a1-12, was obtained. The physical properties of the obtained copolymer (a1) are shown in Table 1, and the physical properties of the component (A) are shown in Table 2.

[0112] [Table 1]

[0113] The abbreviations in Table 1 have the following meanings. Note that, in the following, some of the abbreviations already defined above are repeated. MMA: Methyl methacrylate EA: Ethyl acrylate GMA: Glycidyl methacrylate HEMA: 2-hydroxyethyl methacrylate MEK: Methyl ethyl ketone MOA: Trimethyl orthoacetate (MOA (trade name), manufactured by Nippoh Chemical Industries, Ltd.) DTHP: Di-t-hexyl peroxide (Perhexyl D (trade name), manufactured by NOF Corp.)

[0114] [Table 2]

[0115] The abbreviations in Table 2 have the following meanings. Note that, in the following, some of the abbreviations already defined above are repeated. M5300: ε-caprolactone adduct of acrylic acid (Aronix M-5300 (trade name), manufactured by Toagosei Co., Ltd., average degree of polymerization of caprolactone: 2, number average molecular weight: 300, Tg: -78°C, acid value: 186 mgKOH / g) TPP: Triphenylphosphine PTSA: p-toluenesulfonic acid BHT: Dibutylhydroxytoluene

[0116] 2. Examples 1 to 20, Comparative examples 1 to 4 (UV curable composition) The raw materials shown in Table 3 or Table 4 were used and stirred and mixed according to the ratios shown in Table 3 or Table 4 to prepare ultraviolet-curable compositions, which were then evaluated as follows. The results are shown in Table 3 or Table 4.

[0117] <Evaluation of tensile properties> Lumirror T-60 (product name, PET film manufactured by Toray Industries, Inc., film thickness: 100 μm) was prepared as a base film, tape was attached to both ends of the film, and the ultraviolet-curable compositions obtained in the above Examples and Comparative Examples were applied to the surface of the base film using a bar coater #0 so that the film thickness after drying would be 60 to 80 μm. The film was then dried in a forced air dryer at 90°C for 10 minutes to obtain a coated film having a dried coating film of the composition. Next, a high-pressure mercury lamp manufactured by Eye Graphics Co., Ltd. was used in an air atmosphere, with a focused UVA irradiance of 500 mW / cm. 2 , the irradiation dose per time is 800mJ / cm 2 The coated film was passed twice under the light irradiation on a conveyor. Next, the film having the cured film was cut into strips having a width of 1 cm, and then the cured film was peeled off from the substrate film. The breaking elongation (%) and breaking strength (unit: MPa) of this cured film were measured using a tensile tester (Autograph AGS-J, manufactured by Shimadzu Corporation) at a tensile speed of 5 mm / min. The tensile product was calculated using the following formula. Tensile product = Breaking strength x Elongation / 2

[0118] <Evaluation of heat resistance> Cosmoshine A-4300 (product name, easy-adhesion PET film manufactured by Toyobo Co., Ltd., film thickness: 50 μm) was prepared as a base film, tape was attached to both ends of the film, and the ultraviolet-curable compositions obtained in the above Examples and Comparative Examples were applied to the surface of the base film using a bar coater #0 so that the film thickness after drying was 50 to 60 μm. The film was then dried in a forced air dryer at 90°C for 10 minutes to obtain a coated film having a dried coating film of the composition. Next, a high-pressure mercury lamp manufactured by Eye Graphics Co., Ltd. was used in an air atmosphere, with a focused UVA irradiance of 500 mW / cm. 2 , the irradiation dose per time is 800mJ / cm 2 The coated film was passed twice under the light irradiation on a conveyor. The resulting film having the cured layer was heated in a ventilation dryer at 90° C. for 300 hours, and the color difference and haze before and after heating were measured.

[0119] <Measurement of color difference> The yellowness index (YI) was measured using a spectrophotometer SE-2000 (trade name) manufactured by Nippon Denshoku Industries Co., Ltd. (YI is calculated according to the following formula). YI = 100(1.28X-1.06Z) / Y (X, Y, Z are color coordinates) ΔYI = YI-YI0 (YI0 indicates YI before the heating test)

[0120] <Measurement of haze> Measurement was carried out using NDH2000 (trade name) manufactured by Nippon Denshoku Industries Co., Ltd., and the difference in haze (Δ haze) before and after heating was evaluated.

[0121] <Evaluation of weather resistance> A substrate film, Zeonor ZF14-100 (trade name, manufactured by Zeon Corporation, cycloolefin polymer, film thickness: 100 μm), was prepared, tape was attached to both ends of the film, and the ultraviolet-curable compositions obtained in the above Examples and Comparative Examples were applied to the surface of the substrate film using a bar coater #0 so that the film thickness after drying was 50 to 60 μm. The film was then dried in a forced air dryer at 90°C for 10 minutes, yielding a coated film having a dried coating film of the composition. Next, a high-pressure mercury lamp manufactured by Eye Graphics Co., Ltd. was used in an air atmosphere, with a focused UVA irradiance of 500 mW / cm. 2 , the irradiation dose per time is 800mJ / cm 2 The coated film was passed twice under the light irradiation on a conveyor. The resulting cured film was placed in a metal weather meter (Daipla Wintes Co., Ltd., "DAIPLA METAL WEATHER KU-R5NCI-A" (trade name)) and subjected to an accelerated weathering test. The irradiation conditions were 63°C, 70% RH, and an illuminance of 80 mW / cm. 2 The test was conducted for 300 hours, with a two-minute shower once every two hours. The evaluation was made based on the color difference and haze before and after the test. The color difference and haze were measured in the same manner as above.

[0122] [Table 3]

[0123] [Table 4]

[0124] The abbreviations in Tables 3 and 4 have the following meanings. TSS-100: Isocyanurate-type polyisocyanate of hexamethylene diisocyanate (Duranate TSS-100 (trade name), manufactured by Asahi Kasei Corporation, NCO%: 17.6 wt%, viscosity: 400 mPa·s / 25°C) WT20-100: Isocyanurate-type polyisocyanate of hexamethylene diisocyanate (Duranate WT20-100 (trade name), manufactured by Asahi Kasei Corporation, NCO%: 14.3 wt%, viscosity: 1400 mPa·s / 25°C) WT31-100: Isocyanurate-type polyisocyanate of hexamethylene diisocyanate (Duranate WT31-100 (trade name), manufactured by Asahi Kasei Corporation, NCO%: 17.4 wt%, viscosity: 2500 mPa·s / 25°C) M-215: Diacrylate of ethylene oxide 3 moles of isocyanuric acid adduct (Aronix M-215 (trade name), manufactured by Toagosei Co., Ltd.) M-327: Triacrylate of 3-mol ε-caprolactone adduct with 3-mol ethylene oxide isocyanuric acid adduct (Aronix M-327 (trade name), manufactured by Toagosei Co., Ltd.) M-1200: Polyester-based urethane acrylate (Mw=4,500) [Aronix M-1200 (product name), manufactured by Toagosei Co., Ltd.] Omni184: 1-Hydroxycyclohexyl-phenyl ketone (Omnirad184 (trade name), manufactured by IGM Resins BV)

[0125] The results in Tables 3 and 4 reveal the following: The compositions of Comparative Examples 1 to 4, which did not contain component (B), exhibited insufficient elongation in the tensile properties of the cured products. In contrast, the compositions of Examples 1 to 20, which contained component (B), exhibited excellent elongation in the tensile properties of the cured products, achieving both excellent tensile properties and weather resistance. More specifically, the following examples and comparative examples are compared. Comparison 1: Comparison of the compositions of Examples 3 and 13 to 17 with the composition of Comparative Example 1 (composition containing polymer A-3 as component (A)) Comparison 2: Comparison of the composition of Example 9 and the composition of Comparative Example 2 (composition containing polymer A-9 as component (A)) Comparison 3: Comparison of the composition of Example 11 and the composition of Comparative Example 3 (composition containing polymer A-11 as component (A)) Comparison 4: Comparison of the composition of Example 20 and the composition of Comparative Example 4 (composition containing polymer A-3 as component (A) and M-1200 as component (D)) In Comparisons 1 and 2, the compositions of the comparative examples had insufficient elongation of the cured products compared to the compositions of the examples, and as a result, the tensile product was also insufficient. In Comparison 3, the comparative composition had insufficient breaking strength and elongation of the cured product compared to the example compositions, and as a result, the tensile product was also insufficient. In Comparative Example 4, the comparative composition had insufficient breaking strength and elongation of the cured product compared to the example compositions, resulting in insufficient tensile product, as well as insufficient heat resistance and weather resistance. A comparison between Examples 3 to 8 showed that the greater the molecular weight (Mn, Mw) of component (A) was, the better the breaking strength was, and the more excellent the heat resistance and weather resistance were. A comparison between Examples 3, and 9 to 11 shows that those containing a component (A) with a high acrylic equivalent weight had a high elongation percentage of the cured product. A comparison between Examples 3 and 15 to 17 revealed that there was an optimum point for the blending ratio of component (A) to component (B), i.e., the NCO / OH ratio, and the composition of Example 3, where NCO / OH = 1, was the best overall in terms of the tensile properties, heat resistance, and weather resistance of the cured product.

[0126] 3. Examples 21 to 23, Comparative example 5 (Electron beam curable composition) The raw materials shown in Table 5 were used and stirred and mixed in the amounts shown in Table 5 to prepare electron beam curable compositions. Tape was attached to both ends of a smooth glass plate, and the electron beam curable compositions obtained in the above Examples and Comparative Examples were applied using a bar coater #0 so that the film thickness after drying would be 60 to 80 μm. The film was then dried in a forced air dryer at 90°C for 10 minutes to obtain a coated film having a dried coating film of the composition. The coated film was then irradiated with electron beams using an electron beam irradiation device manufactured by NHV Corporation under conditions of an acceleration voltage of 150 kV, a dose of 150 kGy (adjusted by beam current and transport speed), and an oxygen concentration of 300 ppm or less, to obtain a cured product. The cured product was peeled from the glass plate, and the tensile properties, heat resistance, and weather resistance of the cured product were evaluated in the same manner as in Examples 1 to 20. The results are shown in Table 5. The abbreviations in Table 5 are the same as those in Tables 3 and 4. The composition of Comparative Example 1, which did not contain component (B), had an insufficient elongation percentage of the cured product. In contrast, the compositions of Examples 21 to 23, which contained component (B), also had excellent elongation percentage of the cured product, achieving both excellent tensile properties and weather resistance. In addition, the electron beam curable compositions of Examples 21-23 were superior to the ultraviolet ray curable compositions of Examples 1-20 in heat resistance and weather resistance (particularly YI value).

[0127] [Table 5] [Industrial Applicability]

[0128] The active energy ray-curable composition of the present invention can be suitably used in fields where a cured product having high mechanical properties, weather resistance, and heat resistance is required, and can be used in fields such as coating agents such as paints, adhesives, etc.

Claims

1. An active energy ray-curable composition comprising a (meth)acrylate polymer (A) (hereinafter referred to as "component (A)") modified with an unsaturated double bond-containing oligomer (a2) (hereinafter referred to as "unsaturated oligomer (a2)") having a glass transition temperature (Tg) of -30 to -90°C, and an isocyanate compound (B) (hereinafter referred to as "component (B)"), the component (B) is a hexamethylene diisocyanate isocyanurate-type polyisocyanate, The weight average molecular weight (Mw) of the component (A) is 2,000 to 60,000, the unsaturated oligomer (a2) is an oligomer containing a ring-opened caprolactone structure and having a molecular weight of 250 or more and 2,000 or less, An active energy ray-curable composition comprising 0.5 to 1.5 equivalents of the component (B) relative to 1 equivalent of hydroxyl groups contained in the component (A).

2. 2. The active energy ray-curable composition according to claim 1, wherein the component (A) is a reaction product of a copolymer (a1) (hereinafter referred to as "copolymer (a1)") having a structural unit derived from a (meth)acrylate monomer (a1-1) that does not have a reactive group and a structural unit derived from a (meth)acrylate monomer (a1-2) that has a reactive group, and an unsaturated oligomer (a2) having a group that reacts with the reactive group and an ethylenically unsaturated group.

3. 3. The active energy ray-curable composition according to claim 2, wherein the (meth)acrylate monomer (a1-2) having a reactive group constituting the copolymer (a1) is a (meth)acrylate monomer having a reactive group selected from the group consisting of an epoxy group, a carboxyl group, a hydroxyl group, and an isocyanate group.

4. 4. The active energy ray-curable composition according to claim 3, wherein the (meth)acrylate monomer (a1-2) having a reactive group that constitutes the copolymer (a1) is a (meth)acrylate monomer having an epoxy group, and the unsaturated oligomer (a2) is an oligomer having a carboxyl group.

5. The active energy ray-curable composition according to any one of claims 1 to 4, wherein in the component (A), the unsaturated oligomer (a2) is a (meth)acrylate oligomer.

6. The active energy ray-curable composition according to any one of claims 1 to 5, wherein the weight average molecular weight (Mw) of the component (A) is 2,000 to 50,000.

7. The active energy ray-curable composition according to any one of claims 1 to 6, further comprising an organic solvent (C) (hereinafter referred to as "component (C)").

8. The active energy ray-curable composition according to claim 7 , comprising 70 parts by weight or less of the component (C) per 100 parts by weight of the component (A).

9. The active energy ray-curable composition according to any one of claims 1 to 7, further comprising an ethylenically unsaturated compound (D) (hereinafter referred to as "component (D)").

10. The active energy ray-curable composition according to claim 9 , comprising 70 parts by weight or less of the component (C) per 100 parts by weight of the total of the components (A) and (D).

11. The active energy ray-curable composition according to any one of claims 1 to 10, further comprising a photopolymerization initiator (E).

12. An active energy ray-curable composition for a coating agent, comprising the active energy ray-curable composition according to any one of claims 1 to 11.

13. An active energy ray-curable composition for adhesives, comprising the active energy ray-curable composition according to any one of claims 1 to 11.

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