Curable composition and laminate

Abstract

To provide a curable composition with superior inkjet suitability and superior adhesive strength, and a laminate that is formed using the curable composition and resists peeling.SOLUTION: A curable composition includes a methacryl oligomer with a molecular weight of 2,000 or more (A), a methacryl monomer (B), and a radical polymerization initiator (C), where the methacryl monomer (B) includes an acryl monomer (B1) and a monomer with a methacryloyloxy group and a heterocycle (B2). The curable composition has a viscosity of 50 mPa s or less.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a curable composition and a laminate, and more particularly to a curable composition suitable for bonding two substrates.

Background Art

[0002] Microchannel devices (flow cells) in which fine channels are formed in substrates such as resins, glass, and silicon are known. The microchannel device can perform processes such as mixing, separation, and chemical reactions on fluids containing reagents, specimens, etc. in the microchannels, and can perform optical measurements of the obtained samples. Fluid transport in the microchannels utilizes capillary action and the like, and sometimes utilizes external forces such as vibration and centrifugal force. When utilizing an external force, it is necessary to bond a substrate serving as a lid onto the microchannel.

[0003] When bonding finely processed substrates, the adhesive is required to be printed in a predetermined fine pattern. The inkjet method is suitable for printing the fine pattern. When printing by the inkjet method, the adhesive is required to have a low viscosity. For example, Patent Document 1 discloses a curable resin composition containing a (meth)acrylic oligomer having a molecular weight of 5,000 or more, a (meth)acrylic monomer, and a radical polymerization initiator, and having a viscosity of 150 mPa·s or less.

[0004] Patent Document 2 discloses a specific active energy ray-curable adhesive composition containing an unsaturated compound (A) having one ethylenically unsaturated group and a urethane (meth)acrylate compound (B), which is excellent in coating properties and adhesiveness to an acrylic resin and also excellent in hardness, wherein the unsaturated compound (A) has a cyclic structure and the urethane (meth)acrylate compound (B) has an ether structure and / or a carbonate structure.

[0005] Cycloolefin copolymers (hereinafter sometimes referred to as COP) are being considered as substrates for the aforementioned microfluidic devices. COP is suitable as a substrate for microfluidic devices because it has excellent chemical resistance and is suitable for optical measurements due to its characteristics such as transparency and low birefringence. On the other hand, COP has low wettability, which has resulted in insufficient adhesion when COP substrates are bonded with adhesives. While methods to improve the adhesion of COP include hydrophilization treatment of the COP substrate surface and microfabrication, further improvement in the adhesive strength of the adhesive is needed. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2017-210578 [Patent Document 2] Japanese Patent Publication No. 2017-210607 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] This invention has been made in view of the above circumstances, and aims to provide a curable composition that has excellent inkjet suitability and excellent adhesive strength, and a laminate formed using the curable composition that is difficult to peel off. [Means for solving the problem]

[0008] [1] A (meth)acrylic oligomer (A) with a molecular weight of 2,000 or more, a (meth)acrylic monomer (B), and a radical polymerization initiator (C) The (meth)acrylic monomer (B) comprises an acrylic monomer (B1) and a monomer (B2) having a (meth)acryloyloxy group and a heterocycle. A curable composition having a viscosity of 50 mPa·s or less.

[0009] [2] The curable composition of [1], wherein the (meth)acrylic monomer (B) is present in a total of 100 parts by mass of the (meth)acrylic oligomer (A) and the (meth)acrylic monomer (B), with the (meth)acrylic monomer (B) being 80 to 98 parts by mass.

[0010] [3] A curable composition according to [1] or [2], wherein the acrylic monomer (B1) is 80 to 98 parts by mass in 100 parts by mass of the (meth)acrylic monomer (B).

[0011] [4] A curable composition according to any one of [1] to [3], wherein the monomer (B2) having a (meth)acryloyloxy group and a heterocycle is present in 15 to 40 parts by mass of a total of 100 parts by mass of the (meth)acrylic monomer (B).

[0012] [5] A curable composition according to any one of [1] to [4], comprising 1 to 5 parts by mass of the radical polymerization initiator (C) with respect to a total of 100 parts by mass of the (meth)acrylic oligomer (A) and the (meth)acrylic monomer (B).

[0013] [6] A curable composition according to any one of [1] to [5], wherein the heterocycle comprises a heterocycle having an alkyl group or an oxy group (=O) as a substituent.

[0014] [7] A solvent-free curable composition of any of [1] to [6].

[0015] [8] A curable composition of any of [1] to [7], which is an inkjet ink.

[0016] [9] A laminate having, in this order, a cured layer of any of the curable compositions [1] to [8] and a second substrate on a first substrate.

[0017]

[10] A laminate of [9] wherein the first substrate and / or the second substrate comprises a cycloolefin copolymer. [Effects of the Invention]

[0018] According to the present invention, it is possible to provide a curable composition having excellent inkjet suitability and excellent adhesive strength, and a laminate that is difficult to peel off formed using the curable composition.

Mode for Carrying Out the Invention

[0019] Hereinafter, the curable composition and laminate according to the present invention will be described in detail in order. In the present invention, the (meth)acrylic monomer represents at least one of an acrylic monomer and a methacrylic monomer, and (meth)acrylic oligomers, (meth)acryloyl groups, etc. are also construed accordingly. The acrylic monomer (B1) may be referred to as "monomer (B1)", and the monomer (B2) having a (meth)acryloyloxy group and a heterocyclic ring may be referred to as "monomer (B2)". The same applies to other monomers, oligomers, etc. In addition, "~" indicating a numerical range includes its lower limit value and upper limit value unless otherwise specified.

[0020] [Curable Composition] The curable composition according to the present invention (hereinafter sometimes simply referred to as the present curable composition) contains a (meth)acrylic oligomer (A) having a molecular weight of 2,000 or more, a (meth)acrylic monomer (B), and a radical polymerization initiator (C), and the (meth)acrylic monomer (B) includes an acrylic monomer (B1) and a monomer (B2) having a (meth)acryloyloxy group and a heterocyclic ring, and is characterized in that the viscosity is 50 mPa·s or less. The present curable composition contains the above monomer (B1) and the above monomer (B2) as the monomer (B). The acryloyl group possessed by the monomer (B1) and the heterocyclic ring possessed by the monomer (B2) can both improve the adhesion to the substrate and produce a laminate that is difficult to peel off after curing. The heterocyclic ring of the monomer (B2) is particularly suitable for improving the adhesion to a COP substrate. Further, since the monomer (B2) has a (meth)acryloyl group, it can improve the compatibility with the oligomer (A) and the monomer (B1) while having a heterocyclic ring, and can suppress the viscosity. This curable composition can have its viscosity reduced to 50 mPa·s or less without the addition of solvents, for example, making it highly suitable as an inkjet ink. Furthermore, it can be cured immediately after coating a substrate without the need for drying or other treatments.

[0021] This curable composition contains at least an oligomer (A), a (meth)acrylic monomer (B), and a radical polymerization initiator (C), and may contain other components to the extent that the effects of the present invention are achieved. The components that may be included in this curable composition are described below.

[0022] <(meth)acrylic oligomer (A) with a molecular weight of 2,000 or more> In this curable composition, oligomer (A) has a molecular weight of 2,000 or more. By using an oligomer with a molecular weight of 2,000 or more, a cured product with excellent adhesive strength can be obtained. From the viewpoint of adhesive strength, the molecular weight of oligomer (A) is preferably 2,500 or more, and more preferably 3,000 or more. On the other hand, the upper limit of the molecular weight of oligomer (A) can be appropriately selected within a range that allows the viscosity of the composition to be adjusted to 50 mPa·s or less. From the viewpoint of suppressing viscosity, the molecular weight of oligomer (A) is preferably 100,000 or less, more preferably 50,000 or less, even more preferably 30,000 or less, and particularly preferably less than 20,000. The molecular weight of oligomer (A) was measured by gel permeation chromatography (GPC) and converted using a calibration curve for standard polystyrene to obtain the weight-average molecular weight.

[0023] Oligomer (A) only needs to have one or more (meth)acryloyl groups (CH2=CR-C(=O)-; where R is a hydrogen atom or a methyl group) in its molecule, preferably having two or more (meth)acryloyl groups, and more preferably having two. The presence of (meth)acryloyl groups gives oligomer (A) curability. From the standpoint of adhesive strength and other factors, oligomer (A) is preferably one having (meth)acryloyl groups at both ends of the main chain.

[0024] Examples of polymer chains for oligomer (A) include polyurethane, polyether, polycarbonate, polyester, and polydiene, and may have a block structure in which two or more polymer chains are linked together. Polyurethane or polydiene is preferred in terms of suppressing the viscosity of the composition and providing good adhesion, electrical insulation, water resistance, and transparency. Oligomer (A) can be used alone or in combination of two or more types.

[0025] (Urethane (meth)acrylate oligomer) A polyurethane-containing (meth)acrylic oligomer (hereinafter also called a urethane (meth)acrylate oligomer) is an oligomer having a main chain (polyurethane) with two or more urethane bonds (-NH-C(=O)-O-). Commercially available urethane (meth)acrylate oligomers include UV-3700B (manufactured by Nippon Synthetic Co., Ltd.: molecular weight 38,000), UA10000B (manufactured by KSM Co., Ltd.: molecular weight 25,000), UA01 (manufactured by KSM Co., Ltd.: molecular weight 19,000), UN7700 (manufactured by Negami Kogyo Co., Ltd.: molecular weight 20,000), UN-9200A (manufactured by Negami Kogyo Co., Ltd.: molecular weight 15,000), UN-9000H (manufactured by Negami Kogyo Co., Ltd.: molecular weight 5,000), and EB230 (manufactured by Daicel Cytec Co., Ltd.: molecular weight 5,000).

[0026] Furthermore, urethane (meth)acrylate oligomers can be obtained, for example, by reacting a polyisocyanate with a polyol to form a polyurethane having isocyanate ends, and then reacting the polyurethane with a (meth)acrylate having a hydroxyl group. For specific manufacturing conditions, see, for example, Japanese Patent Application Publication No. 2008-260898.

[0027] The above polyisocyanate only needs to have two or more isocyanate groups in one molecule, and diisocyanate is preferred from the viewpoint of the adhesion of the resulting oligomer. Examples of polyisocyanates include aliphatic diisocyanates such as hexamethylene diisocyanate and trimethylhexamethylene diisocyanate; aromatic isocyanate compounds such as tolylene diisocyanate, diphenylmethane diisocyanate, polyphenylmethane polyisocyanate, modified diphenylmethane diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, phenylene diisocyanate, and naphthalene diisocyanate; hydrogenated aromatic isocyanates (hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate), alicyclic diisocyanates such as isophorone diisocyanate, norbornene diisocyanate, and 1,3-bis(isocyanatomethyl)cyclohexane; and lysine diisocyanate. Urethane prepolymers with terminal isocyanate groups obtained by reacting these diisocyanates with polyols may also be used.

[0028] The above polyol only needs to have two or more hydroxyl groups in one molecule, and a diol is preferred from the viewpoint of the adhesion of the resulting oligomer. Examples of polyols include ethylene glycol, propylene glycol, neopentyl glycol, 3-methyl-1,5-pentanediol, 1,4-butanediol, and 1,6-hexanediol; polyester polyols obtained by the reaction of the above diols with polybasic acids (e.g., succinic acid, phthalic acid, hexahydrophthalic anhydride, terephthalic acid, adipic acid, azelaic acid, tetrahydrophthalic anhydride, etc.); polycaprolactone diols obtained by the reaction of the above diols with caprolactone; polycarbonate polyols (e.g., polycarbonate diols obtained by the reaction of 1,6-hexanediol with diphenyl carbonate, etc.); and polyether polyols such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and ethylene oxide-modified bisphenol A. Furthermore, a hydrogenated polydiene to which two or more hydroxyl groups have been introduced may be used as the polyol. A hydrogenated polydiene to which two or more hydroxyl groups have been introduced can be obtained, for example, by introducing two or more hydroxyl groups to a hydrogenated polydiene such as polybutadiene, polyisoprene, polypentadiene, polyhexadiene, polyoctadiene, polycyclopentadiene, polydicyclopentadiene, or polyethylidene norbornene. Furthermore, the terms "hydrogenated" and "hydrogenated" refer to substances in which hydrogen has been added to unsaturated bonds to create saturated bonds.

[0029] Polyisocyanates and polyols can be used individually or in combination of two or more. The polyols preferably contain hydrogenated polydienes with two or more hydroxyl groups, due to their low curing shrinkage rate during polymerization and excellent adhesion, electrical insulation, water resistance, and transparency.

[0030] Furthermore, the (meth)acrylate having the above-mentioned hydroxyl group only needs to have one or more hydroxyl groups in one molecule, and it is preferable that it has one hydroxyl group in one molecule from the viewpoint of the adhesion of the resulting oligomer. Examples of (meth)acrylates having a hydroxyl group include mono(meth)acrylates such as 2-hydroxyethyl(meth)acrylate, 2-hydroxypropyl(meth)acrylate, 1,4-butanediol mono(meth)acrylate, 1,6-hexanediol mono(meth)acrylate, polyethylene glycol mono(meth)acrylate, and caprolactone-modified hydroxyethyl(meth)acrylate; di(meth)acrylates such as trimethylolpropanedi(meth)acrylate; and polyfunctional(meth)acrylates such as pentaerythritol tri(meth)acrylate and dipentaerythritol penta(meth)acrylate. These can be used individually or in combination of two or more.

[0031] (Polydiene-containing (meth)acryl oligomers) Examples of (meth)acrylic oligomers having the polydiene mentioned above include (meth)acrylic oligomers having polyisoprene or polybutadiene, and the polydiene may be a hydrogenated product. In this invention, oligomers having a urethane bond and a polydiene are treated as the above-mentioned urethane (meth)acrylate oligomers. (Meth)acrylic oligomers containing polydiene can be commercially available. For example, commercially available (meth)acrylate oligomers with a polyisoprene backbone include UC-1 (manufactured by Kuraray Co., Ltd.: molecular weight 25,000) and UC-203 (manufactured by Kuraray Co., Ltd.: molecular weight 35,000).

[0032] The (meth)acryloyl group in oligomer (A) is preferably a (meth)acryloyloxy group. Having a (meth)acryloyloxy group in oligomer (A) improves compatibility with monomer (B2), which will be described later, and improves the storage stability of the composition.

[0033] <(meth)acrylmonomer(B)> This curable composition uses a combination of an acrylic monomer (B1) and a monomer (B2) having a (meth)acryloyloxy group and a heterocycle as the (meth)acrylic monomer (B), and may further contain other monomers to the extent that the effects of the present invention are achieved. By combining monomer (B1) and monomer (B2), it is possible to produce a laminate that is difficult to peel off after curing by improving adhesion to the substrate while suppressing an increase in the viscosity of the composition. Monomer (B) only needs to have one or more (meth)acryloyl groups in its molecule. A monofunctional monomer having one (meth)acryloyl group is preferred because it has low viscosity, excellent curability, and small shrinkage during curing. Furthermore, to suppress the viscosity of the composition, monomer (B) is preferably a liquid with a viscosity of 10 mPa·s or less, preferably 8 mPa·s or less, at room temperature (25°C). Furthermore, some monomers, such as monomers having an acryloyloxy group and a heterocycle, fall under both monomer (B1) and monomer (B2). In this invention, such monomers are defined as falling under both monomer (B1) and monomer (B2), and their content ratios and other properties are specified accordingly.

[0034] (Acrylic monomer (B1)) Acrylic monomer (B1) can be appropriately selected from monomers having an acryloyl group (CH2=CH-C(=O)-). By having a monomer (B1) with an acryloyl group, it is possible to improve adhesion to the substrate and produce a laminate that is less likely to peel off after curing. Examples of monomers (B1) include linear or branched alkyl acrylates, alicyclic acrylates, aromatic acrylates, heterocyclic acrylates, monomers with hydroxyl groups, and acrylamides. Monomers (B1) can be used individually or in combination of two or more.

[0035] Specific examples of monomer (B1) include: Linear or branched alkyl acrylates such as methyl acrylate, ethyl acrylate, isopropyl acrylate, n-propyl acrylate, n-butyl acrylate, isobutyl acrylate, t-butyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, isooctyl acrylate, isodecyl acrylate, lauryl acrylate, stearyl acrylate, and isostearyl acrylate; Monomers having a hydroxyl group, including hydroxyalkyl acrylates such as 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxybutyl acrylate, and 4-hydroxybutyl acrylate, and monomers such as N-hydroxymethyl acrylamide, N-hydroxyethyl acrylamide, 2-acryloyloxyethyl-2-hydroxypropyl phthalate, 2-hydroxy-3-acryloyloxypropyl acrylate, caprolactone-modified 2-hydroxyethyl acrylate, and cyclohexanedimethanol monoacrylate; Acrylates having an alicyclic ring, such as cyclohexyl acrylate, dicyclopentenyloxyethyl acrylate, adamantyl acrylate, dicyclopentanyl acrylate, and isobornyl acrylate; Acrylates having aromatic rings, such as benzyl acrylate and phenyl acrylate; Acrylamides such as methylacrylamide, N-butoxymethylacrylamide, N-methoxyethylacrylamide, and N-ethoxyethylacrylamide; Monomers containing a carboxyl group, such as acrylic acid and carboxyethyl acrylate; Monomers having an amino group, such as dimethylaminomethyl acrylate; Acrylates having a heterocycle, as described later; Examples include allyl acrylate; and others.

[0036] The monomer (B1) preferably comprises one or more selected from linear or branched alkyl acrylates, monomers having a hydroxyl group, acrylates having an alicyclic ring, and acrylates having an aromatic ring, and it is more preferable to use a combination of linear or branched alkyl acrylates, acrylates having an alicyclic ring, and acrylates having an aromatic ring.

[0037] Of the linear or branched alkyl acrylates mentioned above, alkyl acrylates with 6 to 30 carbon atoms in the alkyl group are preferred, and linear alkyl acrylates are more preferred, in terms of reducing the viscosity of the composition and imparting flexibility to the resulting cured product. Furthermore, the number of carbon atoms in the alkyl group of the alkyl acrylate is preferably 6 to 20, and more preferably 8 to 16. Of the monomers having a hydroxyl group, hydroxyalkyl acrylates are preferred from the viewpoint of the curability of the composition and adhesion to the substrate. The number of carbon atoms in the hydroxyalkyl group is preferably 1 to 20, and more preferably 2 to 16. The acrylate having the above-mentioned alicyclic ring preferably has 8 or more carbon atoms, including the alicyclic ring and the substituents it has, and more preferably 8 to 20 carbon atoms.

[0038] ((meth)acryloyloxy group and heterocyclic monomer (B2)) Monomer (B2) is a monomer having a (meth)acryloyloxy group (CH2=CR-C(=O)-O-, where R is a hydrogen atom or a methyl group) and a heterocycle. The presence of a heterocycle in monomer (B2) improves adhesion to the substrate (especially COP substrates), making this curable composition an excellent adhesive for COP substrates. Furthermore, the presence of a (meth)acryloyloxy group in monomer (B2) improves compatibility with oligomer (A) and monomer (B1) while maintaining a heterocycle, thus reducing viscosity. Monomer (B2) can be used alone or in combination of two or more types.

[0039] From the standpoint of structural stability and affinity with the substrate, particularly cycloolefins, the heterocycle preferably has a ring structure of four or more members, and more preferably five or more members. Examples of heteroatoms that the heterocycle may contain include O, S, N, and Si, with O or N being preferred. The number of heteroatoms in the heterocycle may be one or more, preferably 1 to 3, and more preferably 1 to 2.

[0040] The heterocycle may have further substituents on the C, N, and Si atoms that form the ring skeleton. Examples of substituents include alkyl groups, alkoxy groups, halogen atoms, hydroxyl groups, and oxy groups (=O). Among the alkyl groups, linear or branched alkyl groups having 1 to 6 carbon atoms are preferred, and alkyl groups having 1 to 4 carbon atoms are more preferred. Among the alkoxy groups, alkoxy groups having 1 to 4 carbon atoms are preferred, and alkoxy groups having 1 to 2 carbon atoms are preferred. Examples of halogen atoms include fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms. Furthermore, the hydrogen atoms of the alkyl and alkoxy groups may be further substituted with halogen atoms or hydroxyl groups. In the following description of heterocycles, heterocycles having an oxy group as a substituent will be considered to have a heterocycle skeleton that includes the oxy group.

[0041] The heterocycle may be aromatic or non-aromatic. Aromatic ring skeletons include pyrrole, oxazole, imidazole, pyridine, indole, quinoline, and benzofuran skeletons. Furthermore, examples of ring skeletons that do not possess aromaticity include the piperidyl skeleton (formula (1) below), the maleimide skeleton (formula (2) below), the isocyanurate skeleton (formula (3) below), the tetrahydrofuran skeleton (formula (4) below), the dioxolane skeleton (formula (5) below), the cyclic trimethylolpropane skeleton (formula (6) below), the oxetane skeleton (formula (7) below), and the morpholine skeleton (formula (8) below).

[0042] [ka] However, the asterisk (*) in the formula represents a bond that is directly or via a linking group to the (meth)acryloyloxy group, and the hydrogen atoms in the formula may be substituted with alkyl groups, alkoxy groups, halogen atoms, or hydroxyl groups.

[0043] The heterocycle of monomer (B2) is preferably non-aromatic in terms of its affinity with cycloolefins, and among these, the structure represented by the following formulas (1a) to (6a) is preferred.

[0044] [ka] However, * in the formula represents a bond that is directly or via a linking group to the (meth)acryloyloxy group, and R 1 This group is a -CH2CH2OH or (meth)acryloyloxy group.

[0045] Examples of linking groups that connect the (meth)acryloyloxy group to the ring structure include alkyl groups having 1 to 6 carbon atoms. Furthermore, if the (meth)acryloyloxy group is an acryloyloxy group, the compound also corresponds to the monomer (B1) mentioned above.

[0046] (Other monomers) The (meth)acrylic monomer (B) may further contain other monomers. Examples of other monomers include methacrylic monomer (B3) which does not have a heterocycle and other vinyl monomers. The methacrylic monomer (B3) that does not have a heterocycle can be appropriately selected from monomers having a methacryloyl group (CH2=C(CH3)-C(=O)-). Examples of monomers (B3) include linear or branched alkyl methacrylates, alicyclic methacrylates, aromatic methacrylates, monomers with hydroxyl groups, and methacrylamides. Monomers (B3) can be used individually or in combination of two or more.

[0047] Specific examples of monomers (B3) include: Linear or branched alkyl methacrylates such as methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, isooctyl methacrylate, isodecyl methacrylate, lauryl methacrylate, stearyl methacrylate, and isostearyl methacrylate; Hydroxyalkyl methacrylates such as 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2-hydroxybutyl methacrylate, and 4-hydroxybutyl methacrylate, and monomers having a hydroxyl group, including monomers such as N-hydroxymethyl methacrylamide, N-hydroxyethyl methacrylamide, 2-methacryloyloxyethyl-2-hydroxypropyl phthalate, 2-hydroxy-3-methacryloyloxypropyl methacrylate, caprolactone-modified 2-hydroxyethyl methacrylate, and cyclohexanedimethanol monomethacrylate; Alicyclic methacrylates such as cyclohexyl methacrylate, dicyclopentenyloxyethyl methacrylate, adamantyl methacrylate, dicyclopentanyl methacrylate, and isobornyl methacrylate; Methacrylates having aromatic rings, such as benzyl methacrylate and phenyl methacrylate; Methacrylamides such as methyl methacrylamide, N-butoxymethyl methacrylamide, N-methoxyethyl methacrylamide, and N-ethoxyethyl methacrylamide; monomers having a carboxyl group, such as methacrylic acid and carboxyethyl methacrylate; Monomers having an amino group, such as dimethylaminomethyl methacrylate; Examples include allyl methacrylate; and others.

[0048] The monomer (B3) preferably comprises one or more selected from linear or branched alkyl methacrylates, monomers having a hydroxyl group, methacrylates having an alicyclic ring, and methacrylates having an aromatic ring.

[0049] Of the linear or branched alkyl methacrylates mentioned above, alkyl methacrylates having 6 to 30 carbon atoms are preferred, and linear alkyl methacrylates are more preferred, in terms of reducing the viscosity of the composition and imparting flexibility to the resulting cured product. Among these, alkyl methacrylates with 6 to 20 carbon atoms are preferred, and 8 to 16 carbon atoms are more preferred. Of the monomers having a hydroxyl group, hydroxyalkyl methacrylate is preferred from the viewpoint of the curability of the composition and adhesion to the substrate. The number of carbon atoms in the hydroxyalkyl group is preferably 1 to 20, and more preferably 2 to 16. The methacrylate having the above-mentioned alicyclic ring preferably has 8 or more carbon atoms, including the alicyclic ring and the substituents it has, and more preferably 8 to 20 carbon atoms.

[0050] Other vinyl monomers include, for example, styrene monomers such as styrene, vinyltoluene, 2-methylstyrene, t-butylstyrene, and chlorostyrene; and vinyl acetate. Each monomer in monomer (B) can be a commercially available product.

[0051] (Ratio of oligomer (A) to monomer (B)) In this curable composition, the ratio of oligomer (A) to monomer (B) can be adjusted as appropriate. To suppress the viscosity of the composition, improve adhesion and adhesive strength, and impart flexibility to suppress peeling, it is preferable that the (meth)acrylic monomer (B) is present in an amount of 80 to 98 parts by mass, and more preferably 82 to 95 parts by mass, of the total 100 parts by mass of oligomer (A) and monomer (B). From the viewpoint of adhesion to the substrate, the proportion of monomer (B1) is preferably 80 to 98 parts by mass of monomer (B) per 100 parts by mass of monomer (B), and more preferably 81 to 97 parts by mass. From the viewpoint of adhesion to the substrate, the proportion of monomer (B2) is preferably 15 to 40 parts by mass of monomer (B) and more preferably 20 to 35 parts by mass of monomer (B) per 100 parts by mass of monomer (B).

[0052] <Radical polymerization initiator (C)> This curable composition contains a radical polymerization initiator to accelerate curing. The radical polymerization initiator (C) can be used alone or in combination of two or more types. Examples of radical polymerization initiators (C) include photo-radical polymerization initiators and thermal radical polymerization initiators, and either one or a combination thereof may be used. This curable composition preferably contains a photo-radical polymerization initiator from the viewpoint of ease of manufacturing the laminate, and preferably consists substantially of a photo-radical polymerization initiator. In this invention, the radical polymerization initiator is preferably a cleavage-type initiator that generates radicals by cleaving itself upon the action of light or heat. Once a cleavage-type initiator generates radicals, it decomposes, losing its initiator function and reducing its reactivity. Therefore, the risk of unexpected reactions with reagents in microfluidic channels, for example, is suppressed. Furthermore, such cleavage-type initiators exhibit excellent curability, and after decomposition, their light absorption decreases, suppressing discoloration of the cured product and improving transparency. The following radical polymerization initiators are all examples of cleavage-type initiators.

[0053] (Photoradical polymerization initiator) A photoradical polymerization initiator can be any compound that generates radicals upon irradiation with light, and can be selected and used as appropriate. Specific examples of photoradical polymerization initiators include benzophenone, diacetyl, benzyl, benzoin, ω-bromoacetophenone, chloroacetone, acetophenone, 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetone, p-dimethylaminoacetophenone, p-dimethylaminopropiophenone, 2-chlorobenzophenone, p,p'-bisdiethylaminobenzophenone, Michler ketone, benzoin methyl ether, benzoin isobutyl ether, benzoin-n-butyl ether, benzyldimethyl ketal, 1-hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methyl-1-one, 2-hydroxy-2-methyl-1-phenyl-propanone polymer, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one, and methyl Examples of photopolymerization initiators include carbonyl-based photopolymerization initiators such as benzoyl formate, 2,2-diethoxyacetophenone, and 4-N,N'-dimethylacetophenones; sulfide-based photopolymerization initiators such as diphenyl disulfide and dibenzyl disulfide; quinone-based photopolymerization initiators such as benzoquinone and anthraquinone; ultraviolet light initiators such as azobisisobutyronitrile and 2,2'-azobispropane; and visible light initiators such as 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one, 2-dimethylamino-2-(4-methyl-benzyl)-1-(4-morpholinophenyl)-butan-1-one, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, and 2,4,6-trimethylbenzoyl-diphenylphosphine oxide.

[0054] From the viewpoint of sensitivity and curing speed, carbonyl-based photopolymerization initiators or visible light initiators are preferred as photoradical polymerization initiators, and it is even more preferable to use carbonyl-based photopolymerization initiators and visible light initiators in combination. Among carbonyl-based photopolymerization initiators, 1-hydroxycyclohexylphenyl ketone or 2-hydroxy-2-methyl-1-phenyl-propanone polymers are preferred. Furthermore, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide is preferred as a visible light initiator.

[0055] (Thermal radical polymerization initiator) Any compound that generates radicals upon heating can be used as a thermal radical polymerization initiator, and can be selected as appropriate. Examples of thermal radical polymerization initiators include organic peroxides and azo compounds, with organic peroxides being preferred.

[0056] Organic peroxides are compounds containing a peroxy group (-OO-), and examples include diacyl peroxides, hydroperoxides, dialkyl peroxides, peroxyketals, peroxyesters, and peroxycarbonates.

[0057] Specific examples of organic peroxides include diacyl peroxides such as dilauroyl peroxide, dibenzoyl peroxide, and bis-3,5,5-trimethylhexanoyl peroxide; hydroperoxides such as 1,1,3,3-tetramethylbutyl hydroperoxide, cumene hydroperoxide (e.g., Kayacmen H from Kayaku Akzo), and t-butyl hydroperoxide; t-hexylperoxy 2-ethylhexanoate, dicumyl peroxide, and 2,5-dimethyl-2,5-di(t-butylperoxy)hexane. Dialkyl peroxides such as 1,3-bis(t-butylperoxyisopropyl)benzene, t-butylcumyl peroxide, di-t-butyl peroxide, and 2,5-dimethyl-2,5-di(t-butylperoxy)hexine-3; peroxyketals such as 2,2-bis(4,4-di-t-butylperoxycyclohexyl)propane, 1,1-di-t-butylperoxycyclohexane, and 2,2-di-t-butylperoxybutane; and 1,1,3,3-tetramethylbutylperoxyneodecanoate and α-cumylperoxy Syneodecanoate, t-butylperoxyneodecanoate, t-butylperoxyneoheptanoate, t-butylperoxypivalate, 1,1,3,3-tetramethylbutylperoxy2-ethylhexanoate, t-amylperoxy2-ethylhexanoate, t-butylperoxy2-ethylhexanoate, di-t-butylperoxyhexahydroterephthalate, t-amylperoxy3,5,5-trimethylhexanoate, t-butylperoxyacetate, Examples include peroxyesters such as t-butylperoxybenzoate, t-hexylperoxybenzoate, and t-amylperoxybenzoate; and peroxycarbonates such as di-2-ethylhexylperoxydicarbonate, diisopropylperoxydicarbonate, t-butylperoxyisopropyl carbonate, t-butylperoxy2-ethylhexyl carbonate, and 1,6-bis(t-butylperoxycarbonyloxy)hexane.

[0058] Examples of azo compounds include azobisisobutyronitrile, 2,2'-azobis(2-methylisobutyronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl-2,2'-azobis(isobutyrate), and 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile).

[0059] A commercially available radical polymerization initiator (C) can be used. From the viewpoint of curability and adhesive strength after curing, the radical polymerization initiator (C) is preferably in an amount of 1 to 5 parts by mass per 100 parts by mass of the total of the oligomer (A) and monomer (B).

[0060] <Optional addition ingredients> The curable composition may further contain other components to the extent that it achieves the effects of the present invention. Examples of such components include plasticizers, coupling agents, polymerization inhibitors, adhesion promoters, antioxidants, defoamers, pigments, fillers, chain transfer agents, light stabilizers, surface tension modifiers, leveling agents, UV absorbers, antifoaming agents, and solvents.

[0061] Examples of antioxidants include hindered phenol antioxidants, amine antioxidants, phosphorus antioxidants, sulfur antioxidants, and hydrazine antioxidants. Hindered phenol antioxidants are preferred in terms of heat resistance and light resistance. Specific examples of hindered phenol antioxidants include, for example, pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (Irganox 1010, manufactured by BASF), 2,2'-thiodiethylbis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (Irganox 1035, manufactured by BASF), and 4,6-bis(octylthiomethyl Examples include )-o-cresol (Irganox 1520L, manufactured by BASF), 2-tert-butyl-4-methyl-6-(2-hydroxy-3-tert-butyl-5-methylbenzyl)phenyl acrylate (Smirizer GM, manufactured by Sumitomo Chemical), and 1-dimethyl-2-[(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy]ethyl]2,4,8,10-tetraoxaspiro[5.5]undecane (trade name: ADK STAB AO-80, manufactured by ADEKA). In addition, latent antioxidants in which the hindered phenolic hydroxyl group is protected by a protecting group may also be used. Antioxidants can be used individually or in combination of two or more. When an antioxidant is used, the content of the antioxidant is preferably 0.0005 to 0.05 parts by mass, and more preferably 0.001 to 0.01 parts by mass, per 100 parts by mass of the total amount of the curable composition.

[0062] Examples of polymerization inhibitors include phenolic polymerization inhibitors such as 4-methoxyphenol, 2,5-di-tert-butyl-4-methylphenol, 2,6-di-tert-butyl-4-methylphenol, 4,4'-thiobis(3-methyl-6-t-butylphenol), 2,2'-methylenebis(4-methyl-6-t-butylphenol), 2,6-di-tert-butyl-p-cresol, and 4-tert-butylcatechol; hydroquinone polymerization inhibitors such as hydroquinone and 2,6-di-tert-butylhydroquinone; quinone polymerization inhibitors such as benzoquinone; and phenothiazine polymerization inhibitors such as phenothiazine and 2-methoxyphenothiazine. These can be used individually or in combination of two or more. From the viewpoint of storage stability of this curable composition, phenolic polymerization inhibitors or hydroquinone polymerization inhibitors are preferred. When a polymerization inhibitor is used, the content of the polymerization inhibitor is preferably 0.00005 to 0.005 parts by mass, and more preferably 0.0001 to 0.001 parts by mass, per 100 parts by mass of the total amount of the curable composition.

[0063] Furthermore, as coupling agents, silane coupling agents having various reactive functional groups, such as 3-glycidoxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane, and vinyltriethoxysilane, are preferred from the viewpoint of adhesion to the substrate. The coupling agent can be used alone or in combination of two or more. When a coupling agent is used, the content of the coupling agent is preferably 0.0001 to 0.01 parts by mass, and more preferably 0.005 to 0.05 parts by mass, per 100 parts by mass of the total amount of the curable composition.

[0064] This curable composition may contain a solvent as needed. However, it is preferable to be solvent-free from the viewpoint of eliminating the drying step after application and strengthening the adhesive strength after curing. In this invention, "solvent-free" means substantially free of solvents, and more specifically, the solvent content in the curable composition is 0.1% by mass or less, preferably 0.05% by mass or less, and more preferably 0.01% by mass or less.

[0065] <Viscosity of the composition> The viscosity of this curable composition is 50 mPa·s or less. This viscosity of 50 mPa·s or less allows it to be used as an inkjet ink with excellent inkjet suitability. Furthermore, it can be applied to a substrate in a thin film. The viscosity of this curable composition is preferably 45 mPa·s or less, and more preferably 40 mPa·s or less. The lower limit of the viscosity of this curable composition is not particularly limited as long as it allows for inkjet application, and may be below the viscosity measurable by a viscometer. Although not intended to limit the lower limit of the viscosity of the composition, the viscosity of the composition may, for example, be 1 mPa·s or more. In this invention, viscosity is the value measured using a cone-plate viscometer at atmospheric pressure and 25°C.

[0066] Viscosity tends to be lowered by methods such as reducing the molecular weight of oligomer (A), reducing the proportion of oligomer (A) in the composition, or selecting a monomer (B) with low viscosity. These methods can be used to adjust the viscosity, referring to the above-mentioned configurations. Viscosity can also be adjusted by adding a solvent, but it is preferable to adjust it without adding a solvent, as this eliminates the need for a drying step after coating and strengthens the adhesive strength after curing.

[0067] The method for preparing this curable composition is not particularly limited as long as it allows for the dispersion of monomer (B), oligomer (A), radical polymerization initiator (C), and optional additives as needed, and can be mixed using known mixing methods.

[0068] <Method for curing a curable composition> If the curable composition contains a photoradical polymerization initiator, the composition can be cured by energy rays. If the curable composition contains a thermal radical polymerization initiator, the composition can be cured by heating. If the curable composition contains both a photoradical polymerization initiator and a thermal radical polymerization initiator, the composition can be cured by energy rays and / or heating.

[0069] The above-mentioned energy rays are not particularly limited and include active energy rays such as visible light, ultraviolet rays, X-rays, and electron beams. Ultraviolet rays are preferred as the energy rays. As a light source for ultraviolet rays, a light source that emits ultraviolet (UV) rays can be used. Examples of ultraviolet light sources include metal halide lamps, high-pressure mercury lamps, xenon lamps, mercury xenon lamps, halogen lamps, pulsed xenon lamps, and LEDs. The irradiation of energy rays involves an integrated energy ray intensity of 500-10,000 mJ / cm². 2 It is preferable to irradiate in such a manner. The integrated light intensity should be 1,000 to 8,000 mJ / cm². 2 Preferably, the concentration is 1,000 to 6,000 mJ / cm². 2 It is preferable that this is the case.

[0070] When heat curing is performed, the heating temperature and heating time are not particularly limited as long as they are the temperature and time at which the composition heats up and the substrates adhere to each other. The heating temperature is preferably 70 to 120°C, more preferably 80 to 110°C. The heating time is preferably 10 minutes to 2 hours, more preferably 20 minutes to 100 minutes.

[0071] (Uses of this curable composition) This curable composition can be used as a composition for forming a cured product on a substrate, and as an adhesive for bonding substrates together, and is preferably used as an adhesive. Furthermore, because this curable composition has low viscosity and can be applied to a substrate in a thin film, it can be suitably used as an inkjet ink. This curable composition is preferably used as an adhesive for bonding substrates together by inkjet coating.

[0072] [Laminated structure] The laminate according to the present invention (hereinafter also referred to as "this laminate") is characterized by having a cured layer of the curable composition and a second substrate on a first substrate in this order. This laminate has excellent bonding strength because it bonds a first substrate and a second substrate via a cured product of the curable composition.

[0073] The materials of the first and second substrates are not particularly limited and may be selected independently according to the intended use of each substrate. Because this curable composition exhibits excellent transparency, it is also suitable for bonding transparent substrates. Furthermore, when photocuring this curable composition, it is preferable that at least one of the substrates is transparent. Examples of substrate materials include acetylcellulose resins such as triacetylcellulose, polyester resins such as polyethylene terephthalate and polyethylene naphthalate, olefin resins such as polyethylene and polymethylpentene, acrylic resins, polyurethane resins, transparent resins such as polyethersulfone, polycarbonate, polysulfone, polyether, polyetherketone, acronitrile, methacrylonitrile, and cycloolefin copolymer (COP), as well as glass such as soda glass, potash glass, and lead glass, ceramics such as PLZT, and transparent inorganic materials such as quartz and fluorite. In this curable composition, it is preferable that at least one of the first substrate and the second substrate is a substrate containing a cycloolefin copolymer, as this composition exhibits excellent adhesion to COP.

[0074] Furthermore, the first substrate and / or the second substrate may have fine patterns such as microchannels formed on them. Since this curable composition can be applied by inkjet, it is possible to apply it in accordance with the fine patterns.

[0075] The thickness of the cured layer of this curable composition is not particularly limited, but from the viewpoint of bonding strength of the substrate, 1 to 100 μm is preferred, and 30 to 50 μm is more preferred.

[0076] <Method for manufacturing laminates> The method for manufacturing the laminate is not particularly limited, but for example, the laminate can be obtained by coating a first substrate with the curable composition to form a coating film, placing a second substrate on the coating film, and curing the curable composition.

[0077] The coating method for the curable composition can be appropriately selected from known methods. Specific examples include spin coaters, die coaters, dispensers, inkjet printing, screen printing, and gravure printing. This curable composition is suitable for inkjet printing.

[0078] A second substrate is placed on the obtained coating film. After placing the second substrate, a pressure treatment may be performed. The pressure treatment can be carried out using a rubber roller, a flat plate press, or the like.

[0079] The resulting laminate is obtained by curing the coating film of the curable composition by irradiating the laminate with light or by heating the laminate. The curing conditions are as described above.

[0080] The applications of this laminate are not particularly limited, but it can be suitably used, for example, as a microfluidic device made of COP. [Examples]

[0081] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.

[0082] [Preparation of curable compositions] According to the proportions (parts by mass) listed in Table 1, each component was weighed into a container (made of SUS material), and stirred at 200 revolutions per minute for 30 minutes to 1 hour using a Three-One motor (manufactured by Shinto Kagaku Co., Ltd.) at 60-80°C and atmospheric pressure. After confirming that the temperature of the composition had returned to 25°C, the radical polymerization initiator was weighed and uniformly mixed using a Three-One motor at atmospheric pressure and 25°C to prepare the curable compositions of the examples and comparative examples.

[0083] [Measurement of physical properties] The properties of the resulting curable composition were measured as follows. (viscosity) The viscosity of a liquid photocurable resin composition was measured using a viscometer (RE105U: manufactured by Toki Sangyo Co., Ltd.) under atmospheric pressure and at 25°C, with an appropriate cone plate and rotation speed selected. <Evaluation Criteria> ○ (Good): Viscosity was 50 mPa·s or less. × (Unacceptable): Viscosity exceeded 50 mPa·s. If the viscosity is 50 mPa·s or less, it is considered suitable as an inkjet ink.

[0084] (Adhesion) 0.2 g of each curable resin composition obtained above was dropped onto a COP plate (ZEONEX330R, manufactured by Nippon Zeon) with a 50 μm thick spacer placed on it. This was then bonded to a COP film (ZF-14, manufactured by Nippon Zeon) cut to 3 x 10 cm, and the liquid was spread onto the substrate by rolling a rubber roller (SN-Print Rubber Roller No. 1) back and forth five times with a force of approximately 1 kg. After that, a metal halide lamp (ECS-401GX, manufactured by I-Graphics) was used to heat the mixture at 3000 mJ / cm². 2 The specimens were cured by irradiation with light. Using these specimens, a 180° peel test was performed at a tensile speed of 300 mm / min using a tensile testing machine (Minebea TG-2kN). The peel strength was calculated after peeling off approximately 10 mm.

[0085] (curable) The shear modulus (G') was measured at 25°C and a frequency of 1 Hz using a rheometer (Anton Paar, MCR-302) equipped with a glass plate and a UV irradiation unit. Each curable resin composition obtained above was dropped onto a glass plate, controlled to a thickness of 100 μm on an 8 mm diameter flat plate, and after wiping off excess liquid, the measurement of the shear stiffness modulus was started. A high-pressure mercury lamp (Hamamatsu Photonics, LIGHTNINGCURE LC-8) was used at 200 mW / cm². 2The material was irradiated with UV light for 60 seconds, and then allowed to stand for 5 minutes after the irradiation ended. Measurements were continued during this time, and the G' value at the end of the measurement was set to 100%. From the measurement results, the time from the start of UV irradiation until G' reached 80% was determined. The shorter this time, the faster the composition hardens, making it easier to maintain the desired pattern even with low viscosity compositions, and indicating superior curing performance.

[0086] [Table 1]

[0087] <Oligomer (A)> • UA-01: Hydrogenated polyisoprene-based urethane acrylate oligomer (weight-average molecular weight 19,000) manufactured by KSM Corporation; the product contains 85% by mass of urethane acrylate oligomer and 15% by mass of lauryl acrylate; however, the values ​​in Table 1 represent the parts by mass of the oligomer. <Monomer (B1)> • IBOA: Isobornyl acrylate, manufactured by Nippon Shokubai Co., Ltd. LA: Lauryl acrylate manufactured by Kyoeisha Chemical Co., Ltd., and the total amount of lauryl acrylate contained in the above UA-01. • SR-395: Isodecyl acrylate manufactured by Arkema • 4-HBA: 4-hydroxybutyl acrylate manufactured by Osaka Organic Chemical Industry Co., Ltd. <Monomer (B1) and (B2)> • Viscoat 150D: Manufactured by Osaka Organic Chemical Industry Co., Ltd. Tetrahydrofurfuryl alcohol-acrylic acid polymer ester <Monomer (B2)> • LA-82: 1,2,2,6,6-pentamethyl-4-piperidyl methacrylate, manufactured by ADEKA Corporation. <Other monomers (B3)> BZ: Benzyl methacrylate, manufactured by Kyoeisha Chemical Co., Ltd. IB: Isobornyl methacrylate, manufactured by Kyoeisha Chemical Co., Ltd. • HO-250: 2-hydroxyethyl methacrylate, manufactured by Kyoeisha Chemical Co., Ltd. <Radical polymerization initiator (C)> • Omnirad-184: Manufactured by IGM Resins BV, 1-hydroxycyclohexylphenyl ketone (photopolymerization initiator) • KIP-150: Lamberti 2-hydroxy-2-methyl-1-phenyl-propanone polymer (photopolymerization initiator) • Omnirad-819: Manufactured by IGM Resins BV (Bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (photopolymerization initiator)) Irganox1010: BASF-made Pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate) (antioxidant) • BHT: Dibutylhydroxytoluene (polymerization inhibitor) manufactured by Kanto Chemical Co., Ltd. • KBM-403: 3-Glycidoxypropyltrimethoxysilane (silane coupling agent) manufactured by Shin-Etsu Chemical Co., Ltd. • KBM-503: 3-methacryloxypropyltrimethoxysilane (silane coupling agent) manufactured by Shin-Etsu Chemical Co., Ltd.

[0088] As shown in Table 1, the curable compositions of Examples 1 to 6, each containing a (meth)acrylic oligomer (A) with a molecular weight of 2,000 or more, an acrylic monomer (B1), a (meth)acrylic monomer (B) containing a monomer (B2) having a (meth)acryloyloxy group and a heterocyclic group, and a radical polymerization initiator (C), and having a viscosity of 50 mPa·s or less, all exhibited inkjet suitability and were shown to be suitably applicable for lamination of COP substrates.

Claims

1. A (meth)acrylic oligomer (A) having a weight-average molecular weight of 2,000 or more, a (meth)acrylic monomer (B), and a radical polymerization initiator (C), The (meth)acrylic monomer (B) comprises an acrylic monomer (B1) and a monomer (B2) having a (meth)acryloyloxy group and a heterocycle. The viscosity is 50 mPa·s or less. Of the 100 parts by mass of the (meth)acrylic monomer (B), the acrylic monomer (B1) is 80 to 93 parts by mass. Of the 100 parts by mass of the (meth)acrylic monomer (B), the monomer (B2) having the (meth)acryloyloxy group and a heterocycle is 15 to 40 parts by mass. Curable composition.

2. The curable composition according to claim 1, wherein the (meth)acrylic monomer (B) is present in an amount of 80 to 98 parts by mass of the total of 100 parts by mass of the (meth)acrylic oligomer (A) and the (meth)acrylic monomer (B).

3. The curable composition according to claim 1 or 2, comprising 1 to 5 parts by mass of the radical polymerization initiator (C) per 100 parts by mass of the (meth)acrylic oligomer (A) and the (meth)acrylic monomer (B) in total.

4. The curable composition according to claim 1 or 2, wherein the heterocycle comprises a heterocycle having an alkyl group or an oxy group (=O) as a substituent.

5. The curable composition according to claim 1 or 2, wherein 20 to 35 parts by mass of the monomer (B2) having a (meth)acryloyloxy group and a heterocycle are present in 100 parts by mass of the (meth)acrylic monomer (B).

6. A (meth)acrylic oligomer (A) having a weight-average molecular weight of 2,000 or more, a (meth)acrylic monomer (B), and a radical polymerization initiator (C), The (meth)acrylic monomer (B) comprises an acrylic monomer (B1) and a monomer (B2) having a (meth)acryloyloxy group and a heterocycle. Of the total 100 parts by mass of the (meth)acrylic oligomer (A) and the (meth)acrylic monomer (B), the (meth)acrylic monomer (B) is 80 to 98 parts by mass. Of the 100 parts by mass of the (meth)acrylic monomer (B), the acrylic monomer (B1) is 80 to 93 parts by mass, and the monomer (B2) having a (meth)acryloyloxy group and a heterocycle is 15 to 40 parts by mass. The total of 100 parts by mass of the (meth)acrylic oligomer (A) and the (meth)acrylic monomer (B) contains 1 to 5 parts by mass of the radical polymerization initiator (C), A curable composition having a viscosity of 50 mPa·s or less.

7. The curable composition according to claim 6, wherein the heterocycle comprises a heterocycle having an alkyl group or an oxy group (=O) as a substituent.

8. The curable composition according to claim 6 or 7, wherein 20 to 35 parts by mass of the monomer (B2) having a (meth)acryloyloxy group and a heterocycle are present in 100 parts by mass of the (meth)acrylic monomer (B).

9. The curable composition according to claim 1 or 6, which is solvent-free.

10. A curable composition according to claim 1 or 6, which is an inkjet ink.

11. A laminate comprising, in this order, a cured layer of the curable composition described in claim 1 or 6 and a second substrate on a first substrate.

12. The laminate according to claim 11, wherein the first substrate and / or the second substrate comprises a cycloolefin copolymer.

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