Photocurable components

Abstract

The present invention provides a photocurable composition having good creep resistance and peel strength at high temperatures. [Solution] A photocurable composition comprising a polymer (A) having a radical polymerizable group and an isocyanate group, and a monomer (B) having a weight-average molecular weight of 10,000 to 50,000, wherein the amount of the compound having the radical polymerizable group and the isocyanate group added is 2% by mass or less relative to the polymer (A), and the monomer (B) contains nitrogen-containing monomer (b1) in an amount of 20 to 50% by mass relative to the total amount of the polymer (A) and the monomer (B).

Description

Technical Field

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

Background Art

[0002] Various studies have been made on adhesives used for displays and the like. Patent Document 1 describes an adhesive composition containing at least two acrylic resins having different glass transition points as an adhesive excellent in adhesive strength and also excellent in bending durability and the like.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] This disclosure makes it possible to provide a photocurable composition having good creep resistance and peel strength at high temperatures. [Modes for carrying out the invention]

[0007] The embodiments of the present invention will be described in detail below. The present invention is not limited to the embodiments described below.

[0008] In this disclosure, numerical ranges indicated using "~" represent a range that includes the numbers before and after "~" as the minimum and maximum values, respectively. In numerical ranges described stepwise in this disclosure, the upper or lower limit of one numerical range may be replaced with the upper or lower limit of another numerical range. Furthermore, the upper or lower limits of numerical ranges described in this disclosure may be replaced with the values ​​shown in the examples.

[0009] In this disclosure, each component may contain one or more of the applicable substances unless otherwise specified.

[0010] In this disclosure, the content of each component in the photocurable composition means the total amount of multiple substances present in the photocurable composition if there are multiple substances corresponding to each component, unless otherwise specified.

[0011] A photocurable composition according to one embodiment of the present disclosure comprises a polymer (A) (hereinafter sometimes simply referred to as polymer (A)) having a weight-average molecular weight of 10,000 to 50,000, to which a compound having a radical polymerizable group and an isocyanate group is added, and a monomer (B), wherein the amount of compound having a radical polymerizable group and an isocyanate group added is 2% by mass or less relative to polymer (A), and monomer (B) contains nitrogen-containing monomer (b1) (hereinafter sometimes simply referred to as monomer (b1)) in an amount of 20 to 50% by mass relative to the total amount of polymer (A) and monomer (B), and is a photocurable composition.

[0012] The following describes the photocurable compositions of the embodiments. In this specification, "(meth)acrylic" means acrylic and / or methacrylic, "(meth)acrylate" means acrylate and / or methacrylate, and "(meth)acryloyl" means acryloyl and / or methacryloyl.

[0013] From the viewpoint of good creep resistance, polymer (A) is preferably a polymer to which a compound having a radical polymerizable group and an isocyanate group is added. Examples of radical polymerizable groups include (meth)acryloyl groups. Examples of (meth)acryloyl groups include (meth)acryloyloxy groups.

[0014] Examples of compounds having a radical polymerizable group and an isocyanate group include, for example, compounds having a (meth)acryloyl group and an isocyanate group. Specific examples of compounds having a radical polymerizable group and an isocyanate group include, for example, 2-methacryloyloxyethyl isocyanate (MOI), 2-acryloyloxyethyl isocyanate (AOI), 2-(2-methacryloyloxyethyloxy)ethyl isocyanate, and 1,1-(bisacryloyloxymethyl)ethyl isocyanate.

[0015] Polymer A can be obtained, for example, by adding a compound having a radical polymerizable group and an isocyanate group to a polymer (prepolymer) having a group that can react with an isocyanate group. Polymer A can be obtained, for example, by adding a compound having a radical polymerizable group and an isocyanate group to a polymer having a hydroxyl group. In this way, a site modified by the compound having a radical polymerizable group and an isocyanate group can be introduced into the polymer. More specifically, for example, a urethane bond can be formed by the reaction between the hydroxyl group of a polymer having a hydroxyl group and the isocyanate group of a compound having a radical polymerizable group and an isocyanate group. In this way, a radical polymerizable group can be introduced into the polymer. Polymer A may have, for example, radical polymerizable groups, and in polymer A, the radical polymerizable groups may be bonded to the main chain via urethane bonds. Polymer A may have, for example, a (meth)acryloyloxy group, and in polymer A, the (meth)acryloyloxy group may be bonded to the main chain via a urethane bond.

[0016] A polymer having a hydroxyl group may, for example, be a polymer having structural units derived from a monomer having a hydroxyl group. Examples of monomers having a hydroxyl group include (meth)acrylates having a hydroxyl group, and examples of (meth)acrylates having a hydroxyl group include alkyl (meth)acrylates having an alkyl group substituted with a hydroxyl group. The number of carbon atoms in the alkyl group substituted with a hydroxyl group may be, for example, 3 or less. Specific examples of monomers having a hydroxyl group include hydroxyethyl (meth)acrylate and hydroxypropyl (meth)acrylate. One of these monomers having a hydroxyl group may be used alone, or two or more may be used in combination. Hydroxypropyl (meth)acrylate and 2-hydroxyethyl acrylate are particularly preferred.

[0017] The polymer having hydroxyl groups may be, for example, a polymer obtained by polymerizing a monomer having hydroxyl groups, or a monomer mixture containing a monomer having hydroxyl groups. Examples of monomers other than those containing hydroxyl groups that can be included in the monomer mixture include alkyl (meth)acrylates and N-vinylpyrrolidone. From the viewpoint of improving creep resistance at high temperatures, it is preferable that the monomer mixture contains N-vinylpyrrolidone. The number of carbon atoms in the alkyl(meth)acrylate is preferably 4 or more, more preferably 6 or more, and even more preferably 8 or more. The number of carbon atoms in the alkyl(meth)acrylate may be, for example, 4 to 30, 6 to 20, or 8 to 20. Examples of alkyl(meth)acrylates include methyl(meth)acrylate, ethyl(meth)acrylate, propyl(meth)acrylate, butyl(meth)acrylate, isobutyl(meth)acrylate, ethylhexyl(meth)acrylate (2-ethylhexyl(meth)acrylate), octyl(meth)acrylate, isooctyl(meth)acrylate, isononyl(meth)acrylate, isodecyl(meth)acrylate, lauryl(meth)acrylate, isobornyl(meth)acrylate, etc. One of these monomers may be used alone, or two or more may be used in combination.

[0018] A polymer having hydroxyl groups may be, for example, a polymer obtained by polymerizing a monomer mixture containing a monomer having hydroxyl groups and at least one selected from the group consisting of alkyl (meth)acrylate and N-vinylpyrrolidone. A polymer having hydroxyl groups may contain, for example, structural units derived from a monomer having hydroxyl groups and at least one structural unit selected from the group consisting of structural units derived from alkyl (meth)acrylate and structural units derived from N-vinylpyrrolidone. From the viewpoint of improving creep resistance at high temperatures, it is preferable that the polymer having hydroxyl groups contains structural units derived from N-vinylpyrrolidone.

[0019] When adding a compound having a radically polymerizable group and an isocyanate group to a polymer having a hydroxyl group, a part of the hydroxyl groups of the polymer may remain unused in the reaction with the compound having a radically polymerizable group and an isocyanate group. The polymer (A) may have, for example, a hydroxyalkyloxycarbonyl group. The addition amount of the compound having a radically polymerizable group and an isocyanate group may be, for example, 2 parts by mass or less, 1.5 parts by mass or less, or 1 part by mass or less with respect to 100 parts by mass of the polymer having a hydroxyl group. The addition amount of the compound having a radically polymerizable group and an isocyanate group may be 0.001 parts by mass or more, 0.01 parts by mass or more, or 0.1 parts by mass or more with respect to 100 parts by mass of the polymer having a hydroxyl group. The addition amount of the compound having a radically polymerizable group and an isocyanate group may be, for example, 0.001 to 2 parts by mass, 0.001 to 1.5 parts by mass, 0.001 to 1 part by mass, 0.01 to 1 part by mass, or 0.1 to 1 part by mass with respect to 100 parts by mass of the polymer having a hydroxyl group.

[0020] The polymer A may be, for example, a polymer containing at least one selected from the group consisting of a structural unit derived from a monomer having a hydroxyl group to which a compound having a radically polymerizable group and an isocyanate group is added, a structural unit derived from a monomer having a hydroxyl group and having a hydroxyl group, a structural unit derived from an alkyl (meth) acrylate, and a structural unit derived from N-vinylpyrrolidone. The structural unit to which a compound having a radically polymerizable group and an isocyanate group is added may be a structural unit derived from a monomer having a hydroxyl group. From the viewpoint of improving creep resistance at high temperatures, it is preferable that the polymer A contains a structural unit derived from N-vinylpyrrolidone.

[0021] From the viewpoint of improving peel strength at high temperatures, the addition amount of the compound having a radically polymerizable group and an isocyanate group is preferably 2% by mass or less with respect to the polymer (A). The addition amount of the compound having a radically polymerizable group and an isocyanate group may be, for example, 1.5% by mass or less or 1% by mass or less with respect to the polymer (A).

[0022] The amount of compound having a radical polymerizable group and an isocyanate group added is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, and even more preferably 0.1% by mass or more, relative to polymer (A). The amount of compound having a radical polymerizable group and an isocyanate group added may be, for example, 0.001 to 2% by mass, 0.001 to 1.5% by mass, 0.001 to 1% by mass, 0.01 to 1% by mass, or 0.1 to 1% by mass, relative to polymer (A).

[0023] The weight-average molecular weight of polymer A is preferably 10,000 to 50,000. The weight-average molecular weight of polymer A may be, for example, 10,000 or more, 12,500 or more, 15,000 or more, or 20,000 or more. On the other hand, the weight-average molecular weight of polymer A may be, for example, 50,000 or less, 45,000 or less, or 40,000 or less. The weight-average molecular weight of polymer A may be, for example, 10,000 to 45,000, 10,000 to 40,000, 12,500 to 45,000, or 15,000 to 40,000, or 20,000 to 40,000. From the viewpoint of improving creep resistance at high temperatures, the weight-average molecular weight of polymer A is preferably 12,500 or more, more preferably 15,000 or more, and even more preferably 20,000 or more. In this disclosure, weight-average molecular weight refers to a value calculated from a calibration curve using standard polystyrene by gel permeation chromatography (GPC).

[0024] The method for producing polymer A is not particularly limited. For example, it can be produced by a method that involves producing a polymer having hydroxyl groups using a solution polymerization method, forming a urethane bond by reaction between the hydroxyl groups of the polymer and the isocyanate groups of a compound having radical polymerizable groups and isocyanate groups, and then adding the compound having radical polymerizable groups and isocyanate groups. The method for producing polymer A may include, for example, adding a compound having radical polymerizable groups and isocyanate groups to a polymer having hydroxyl groups and then desolving it. In the production of polymers containing hydroxyl groups, solvents used in solution polymerization include, for example, ethyl acetate, toluene, hexane, acetone, and methyl ethyl ketone. Initiators such as t-butyl 2-ethyl peroxyhexanoate (hereinafter sometimes referred to as "polymerization initiators") may also be used for polymerization. In the step of adding a compound having a radical polymerizable group and an isocyanate group to a polymer having a hydroxyl group and then desolving it, a catalyst such as dioctyl tin dilaurate may be used. Alternatively, for example, 3,5-di-tert-butyl-4-hydroxytoluene (BHT), 4-methoxyphenol, etc. may be used.

[0025] The photocurable composition may contain one polymer (A) alone or a combination of two or more polymers (A).

[0026] The polymer (A) content may be 1% by mass or more, 10% by mass or more, or 20% by mass or more, relative to the total amount of polymer (A) and monomer (B). On the other hand, the polymer (A) content may be 50% by mass or less, 40% by mass or less, or 30% by mass or less, relative to the total amount of polymer (A) and monomer (B). The polymer (A) content may be, for example, 1 to 50% by mass, 10 to 40% by mass or 20 to 30% by mass, relative to the total amount of polymer (A) and monomer (B).

[0027] As monomer (B), one or more monomers (B) including nitrogen-containing monomer (b1) can be used. Examples of nitrogen-containing monomers (b1) include monomers having nitrogen-containing groups such as amino groups and amide groups. Specifically, examples include dimethyl(meth)acrylamide, aminomethyl(meth)acrylate, diethyl(meth)acrylamide, N-vinylpyrrolidone, and 4-acryloylmorpholine. Among these, (meth)acrylamide monomers such as dimethyl(meth)acrylamide are preferred. Nitrogen-containing monomers (b1) may be used individually or in combination of two or more.

[0028] The nitrogen-containing monomer (b1) is preferably in an amount of 20 to 50% by mass relative to the total amount of polymer (A) and monomer (B). From the viewpoint of improving peel strength at high temperatures, the nitrogen-containing monomer (b1) is preferably 20 to 50% by mass, more preferably 20 to 40% by mass, and even more preferably 20 to 30% by mass, relative to the total amount of polymer (A) and monomer (B).

[0029] Monoma(B) may include monoma(b2) having an alkyl group with 4 or more carbon atoms (hereinafter sometimes simply referred to as monoma(b2)). The number of carbon atoms in the alkyl group of monoma(b2) may be, for example, 6 or more, or 8 or more. The number of carbon atoms in the alkyl group of monoma(b2) may be, for example, 4 to 30, 6 to 20, or 8 to 20. Monoma(b2) having an alkyl group with 4 or more carbon atoms may be, for example, an alkyl (meth)acrylate having an alkyl group with 4 or more carbon atoms. Examples of monomer (b) include butyl (meth)acrylate, hydroxybutyl (meth)acrylate, isobutyl (meth)acrylate, ethylhexyl (meth)acrylate (2-ethylhexyl (meth)acrylate), octyl (meth)acrylate, isooctyl (meth)acrylate, isononyl (meth)acrylate, isodecyl (meth)acrylate, lauryl (meth)acrylate, isobornyl (meth)acrylate, etc. One of these may be used alone or in combination of two or more. Ethylhexyl (meth)acrylate (2-ethylhexyl (meth)acrylate), hydroxybutyl (meth)acrylate, isobornyl (meth)acrylate, and isodecyl (meth)acrylate are particularly preferred.

[0030] The monomer (b2) having an alkyl group with 4 or more carbon atoms may be, for example, 30-70% by mass, 35-65% by mass, or 40-60% by mass relative to the total amount of polymer (A) and monomer (B).

[0031] The photocurable composition may contain a photoinitiator (hereinafter sometimes referred to as a "photopolymerization initiator"). Examples of photoinitiators include acetophenone-based photoinitiators such as 2,2-dimethoxy-1,2-diphenylethane-1-one, 4-phenoxydichloroacetophenone, 4-t-butyl-dichloroacetophenone, 4-t-butyl-trichloroacetophenone, diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropane-1-one, 1-(4-isopropylphenyl-2-hydroxy-2-methylpropane-1-one, 1-(4-dodecylphenyl)-2-hydroxy-2-methylpropane-1-one, 4-(2-hydroxyethoxy)-phenyl-(2-hydroxy-2-propyl)ketone, 1-hydroxycyclohexylphenyl ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropane-1, etc.; benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, Examples of photoinitiators include benzoin-based photoinitiators such as benzoin isobutyl ether and benzyldimethyl ketal; benzophenone-based photoinitiators such as benzophenone, benzoylbenzoic acid, methyl benzoylbenzoate, 4-phenylbenzophenone, hydroxybenzophenone, 4-benzoyl-4'-methyldiphenyl sulfide, and 3,3'-dimethyl-4-methoxybenzophenone; and thioxanthone-based photoinitiators such as thioxanthone, 2-chlorthioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone, 2,4-diethylthioxanthone, and 2,4-diisopropylthioxanthone. One of these polymerization initiators may be used alone or in combination of two or more. 2,2-dimethoxy-1,2-diphenylethane-1-one is particularly preferred as a photopolymerization initiator.

[0032] The photoinitiator may be, for example, 0.1 to 20 parts by mass or 1 to 10 parts by mass per 100 parts by mass of the total amount of polymer (A) and monomer (B).

[0033] The photocurable composition may also contain other components such as antioxidants.

[0034] In some embodiments, the viscosity of the photocurable composition at 25°C is preferably 1 to 60 mPa·s, more preferably 1 to 40 mPa·s, and even more preferably 1 to 30 mPa·s. The viscosity mentioned above can be measured, for example, using a viscometer (RE-85R viscometer manufactured by Toki Sangyo Co., Ltd.) at a set temperature of 25°C and a rotation speed of 100 rpm. In some embodiments, the photocurable composition can be suitably used for inkjet coating (hereinafter, the photocurable composition used for inkjet coating will also be referred to as the inkjet photocurable composition). The viscosity of the photocurable composition for inkjet printing at 25°C may be, for example, 1 to 60 mPa·s, 1 to 40 mPa·s, or 1 to 30 mPa·s. For example, in some embodiments, when the viscosity of the photocurable composition at 25°C is 1 to 30 mPa·s, it is suitable for, for example, a general piezo or thermal inkjet printing apparatus. Also, in some embodiments, when the viscosity of the photocurable composition at 25°C is greater than 30 mPa·s and less than or equal to 60 mPa·s (for example, 31 to 60 mPa·s), it is suitable for, for example, a heated coating inkjet apparatus or a high-viscosity compatible inkjet apparatus.

[0035] A cured product can be obtained using the photocurable composition described above. For example, a cured product can be obtained by photocuring the photocurable composition by irradiating it with active energy rays such as ultraviolet (UV), electron beams, alpha rays, beta rays, and gamma rays.

[0036] The above-described photocurable compositions and cured products can be used in a variety of applications, such as smartphones, in-car displays, and PC devices. Furthermore, one embodiment of this disclosure relates to an adhesive using the above-described photocurable composition. In some embodiments, the photocurable composition may be used, for example, as an adhesive. Furthermore, one embodiment of the present disclosure relates to a laminate using the above-described photocurable composition. In some embodiments, the laminate may include layers obtained using the photocurable composition of the embodiment. In some embodiments, the laminate may have a structure in which two or more layers are laminated via layers obtained using the photocurable composition of the embodiment.

[0037] This disclosure includes the following embodiments. The present invention is not limited to the following embodiments. <1> A polymer (A) having a radical polymerizable group and an isocyanate group added to it, and having a weight-average molecular weight of 10,000 to 50,000, A photocurable composition comprising monoma(B), The amount of the compound having the radical polymerizable group and the isocyanate group added is 2% by mass or less relative to polymer (A). The monomer (B) is a photocurable composition containing nitrogen-containing monomer (b1) in an amount of 20 to 50% by mass relative to the total amount of polymer (A) and monomer (B). <2> The monomer (B) further comprises monomer (b2) having an alkyl group having 4 or more carbon atoms. <1> The photocurable composition described in [reference]. <3> The compound having the radical polymerizable group and the isocyanate group is a compound having a (meth)acryloyl group and an isocyanate group. <1> or <2> The photocurable composition described in [reference]. <4> The polymer A has radical polymerizable groups, and the radical polymerizable groups are bonded to the main chain via urethane bonds. <1> or <2> The photocurable composition described in [reference]. <5> The polymer (A) has a hydroxyalkyloxycarbonyl group, <1> ~ <4> A photocurable composition according to any one of the following items. <6> The weight-average molecular weight of polymer A is 10,000 to 40,000. <1> ~ <5> A photocurable composition according to any one of the following items. <7> The amount of the compound having the radical polymerizable group and the isocyanate group added is 0.001 to 1% by mass relative to polymer (A). <1> ~ <6> A photocurable composition according to any one of the following items. <8> The amount of the nitrogen-containing monomer (b1) is 20 to 30% by mass relative to the total amount of polymer (A) and monomer (B). <1> ~ <7> A photocurable composition according to any one of the following items. [Examples]

[0038] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples.

[0039] [Weight average molecular weight] The weight-average molecular weight was calculated from a calibration curve using standard polystyrene by gel permeation chromatography (GPC). The measurement conditions for the GPC method are as follows: Equipment: HLC-8320GPC manufactured by Tosoh Corporation (with built-in radioisotope detector) Detector: RI (Differential Refractometer) Solvent: Pure primary THF (tetrahydrofuran) Guard column: TSK-guardcolumnSuperMP(HZ)-H (1 piece) Guard column size: 4.6mm (ID) x 20mm Column: TSK-GEL Super Multipore HZ-H (3-column linked) manufactured by Tosoh Corporation Column size: 4.6mm (ID) x 150mm Temperature: 40℃ Sample concentration: 0.01 g / 5 mL Injection volume: 10μL Flow rate: 0.35mL / min

[0040] [Production of the composition] Tables 1-3 show the details of the compositions of the examples and comparative examples. In Tables 1-3, the "Composition and Mass Ratio" of the "polymer" indicates the monomer composition and mass ratio of the monomer composition of the acrylic polymerization intermediate (polymer main chain) produced in step 1 of the polymer manufacturing method described below. In Examples 1-8 and Comparative Examples 2-4, the MOI (2-methacryloyloxyethyl isocyanate) or AOI (2-acryloyloxyethyl isocyanate) listed in the table is added to this acrylic polymerization intermediate (polymer main chain). In the table, "AOI (parts by mass)" and "MOI (parts by mass)" indicate the amount of AOI or MOI used per 100 parts by mass of acrylic polymerization intermediate in step 2 of the polymer manufacturing method described below (unit: parts by mass). Tables 1-3 show the compositional materials and their proportions (in parts by mass) under "Composition Composition (parts by mass)". Additionally, the viscosity (in mPa·s) of each composition at 25°C is shown under "Composition Viscosity (mPa·s, 25°C)".

[0041] Details of each material in the table are as follows: 2-EHA:2-Ethylhexylacrylate HEA: Hydroxyethyl acrylate IBXA: Isobornyl acrylate NVP: N-vinylpyrrolidone HPA: Hydroxypropyl acrylate MOI: 2-Methacryloyloxyethyl isocyanate AOI: 2-Acryloyloxyethyl isocyanate FA-111A: Isodecyl acrylate (FA-111A manufactured by Resonac Co., Ltd.) DMAA: N,N-dimethylacrylamide 4-HBA:4-hydroxybutyl acrylate Initiator: 2,2-dimethoxy-1,2-diphenylethane-1-one (Omnirad651, manufactured by IGM Resin)

[0042] (Polymer manufacturing) Polymers for Examples 1-8 and Comparative Examples 1-4 were prepared as follows. (Example 1) Process 1: Polymerization process Methyl ethyl ketone (MEK), the solvent, was added to a stainless steel pressurized reactor equipped with a stirrer, thermometer, reflux condenser, dropping device, and nitrogen inlet tube, and the mixture was stirred. Next, the system was heated to 120°C while blowing nitrogen into the added solvent. Then, a mixture of 60 parts by mass of 2-ethylhexyl acrylate (2-EHA), 20 parts by mass of 2-hydroxyethyl acrylate (HEA), 11 parts by mass of isobornyl acrylate (IBXA), and 11 parts by mass of N-vinylpyrrolidone (NVP), the monomers, and 0.8 parts by mass of t-butyl 2-ethyl peroxyhexanoate (manufactured by NOF Corporation, trade name: Perbutyl O), the polymerization initiator, was added dropwise at a uniform rate over 2.5 hours. Finally, all monomers were added dropwise, and the mixture was kept warm for 1.5 hours. Next, as a deactivation step for the polymerization initiator, the mixture was heated to 125°C under a pressure of 0.3 MPa and maintained at that temperature for 2.5 hours to obtain an acrylic polymerization intermediate, which is a polymer containing hydroxyl groups and has a solid content of 50% by mass.

[0043] Step 2: Addition and desolvation process of a compound having a radical polymerizable group and an isocyanate group. As described below, a compound having a radical polymerizable group and an isocyanate group was added to the acrylic polymerization intermediate obtained above to introduce a radical polymerizable group, and then desolvated to obtain an acrylic polymer polymer. In a separable flask equipped with a stirrer, thermometer, air inlet, and vacuum pump, 100 parts by mass of the deactivated acrylic polymerization intermediate was charged, and the mixture was stirred while bubbling air into it, and the temperature was raised to 70°C. After maintaining the temperature at 70°C for 2 hours, 0.5 parts by mass of 2-methacryloyloxyethyl isocyanate (MOI) was added, and the temperature was maintained for 1 hour. Furthermore, 0.05 parts by mass of dioctyltin dilaurate was added, and the temperature was maintained at 70°C for 2 hours. Subsequently, 0.03 parts by mass of 3,5-di-tert-butyl-4-hydroxytoluene (BHT) and 0.03 parts by mass of 4-methoxyphenol were added, and the temperature was raised to 85°C, at which point the pressure was reduced using a vacuum pump. The pressure inside the flask was reduced while carefully monitoring for foaming, and the temperature was raised to 90°C while the solvent was distilled off. The mixture was kept at 90°C while maintaining reduced pressure. After 2 hours, gas chromatography confirmed that the amount of solvent remaining in the system was 0.02% by mass or less, and the polymer was obtained.

[0044] (Example 2) Process 1 Methyl ethyl ketone (MEK), the solvent, was added to a stainless steel pressurized reactor equipped with a stirrer, thermometer, reflux condenser, dropping device, and nitrogen inlet tube, and the mixture was stirred. Next, the system was heated to 100°C while blowing nitrogen into the added solvent. Then, a mixture of 50 parts by mass of 2-EHA, 50 parts by mass of hydroxypropyl acrylate (HPA), and 0.2 parts by mass of t-butyl 2-ethyl peroxyhexanoate, the polymerization initiator, was added dropwise over 2.5 hours in uniform amounts. After adding all the monomers dropwise, the mixture was kept warm for 1.5 hours. Next, as a deactivation step for the polymerization initiator, the mixture was heated to 125°C under a pressurized condition of 0.3 MPa and kept warm for 2.5 hours to obtain an acrylic polymerization intermediate with a solid content of 50% by mass. Process 2 Using the acrylic polymerization intermediate obtained above, a polymer was obtained in the same manner as in step 2 of Example 1.

[0045] (Example 3, Example 7, Comparative Example 3, Comparative Example 4) Process 1 An acrylic polymerization intermediate was obtained in the same manner as in Step 1 of Example 2, except that the polymerization initiator used was 0.8 parts by mass of t-butyl 2-ethyl peroxyhexanoate and the temperature during dropwise addition was changed to 120°C. Process 2 Using the acrylic polymerization intermediate obtained above, a polymer was obtained in the same manner as in step 2 of Example 1.

[0046] (Example 4) Process 1 An acrylic polymerization intermediate was obtained in the same manner as in Step 1 of Example 3. Process 2 Using the acrylic polymerization intermediate obtained above, a polymer was obtained in the same manner as in step 2 of Example 1, except that the MOI was replaced with 2-acryloyloxyethyl isocyanate (AOI).

[0047] (Example 5) Process 1 An acrylic polymerization intermediate was obtained in the same manner as in Step 1 of Example 1. Process 2 Using the acrylic polymerization intermediate obtained above, a polymer was obtained in the same manner as in step 2 of Example 1, except that the MOI was changed to 1 part by mass.

[0048] (Example 6) Process 1 An acrylic polymerization intermediate was obtained in the same manner as in Step 1 of Example 1, except that the monomers used were replaced with 60 parts by mass of 2-EHA, 20 parts by mass of HEA, 20 parts by mass of IBXA, and 2 parts by mass of NVP. Process 2 Using the acrylic polymerization intermediate obtained above, a polymer was obtained in the same manner as in step 2 of Example 1.

[0049] (Example 8) Process 1 An acrylic polymerization intermediate was obtained in the same manner as in Step 1 of Example 3, except that the monomers used were replaced with 70 parts by mass of 2-EHA and 30 parts by mass of HEA. Process 2 Using the acrylic polymerization intermediate obtained above, a polymer was obtained in the same manner as in step 2 of Example 1.

[0050] (Comparative Example 1) Process 1 An acrylic polymerization intermediate was obtained in the same manner as in Step 1 of Example 3. Process 2 Using the acrylic polymerization intermediate obtained above, a polymer was obtained in the same manner as in step 2 of Example 1, except that no MOI was added.

[0051] (Comparative Example 2) Process 1 An acrylic polymerization intermediate was obtained in the same manner as in Step 1 of Example 3. Process 2 Using the acrylic polymerization intermediate obtained above, a polymer was obtained in the same manner as in step 2 of Example 1, except that the MOI was changed to 3 parts by mass.

[0052] (Comparative Example 5) Process 1 An acrylic polymerization intermediate was obtained in the same manner as in step 1 of Example 8. Process 2 Using the acrylic polymerization intermediate obtained above, a polymer was obtained in the same manner as in step 2 of Example 1, except that no MOI was added.

[0053] (Production of the composition) Using the polymer obtained as described above, along with the monomers and initiators listed in Tables 1-3, compositions for Examples 1-8 and Comparative Examples 1-5 were prepared as follows.

[0054] (Example 1, Example 2, Example 3, Example 4, Example 5, Example 6, Comparative Example 1, Comparative Example 2, Comparative Example 5) The composition was prepared by blending 25 parts by mass of polymer with 20 parts by mass of monomers: isodecyl acrylate (FA-111A), 20 parts by mass of monomers: isobornyl acrylate (IBXA), 20 parts by mass of monomers: dimethylacrylamide (DMAA), and 15 parts by mass of monomers: 4 parts by mass of photopolymerization initiator: 2,2-dimethoxy-1,2-diphenylethane-1-one (Omnirad651).

[0055] (Example 7) The composition was prepared by blending 25 parts by mass of polymer with 10 parts by mass of monomers: isodecyl acrylate (FA-111A), 20 parts by mass of monomers: isobornyl acrylate (IBXA), 30 parts by mass of monomers: dimethylacrylamide (DMAA), and 15 parts by mass of monomers: 4 parts by mass of photopolymerization initiator: 2,2-dimethoxy-1,2-diphenylethane-1-one (Omnirad651).

[0056] (Comparative Example 3) The composition was prepared by blending 25 parts by mass of polymer with 30 parts by mass of monomers: isodecyl acrylate (FA-111A), 20 parts by mass of monomers: isobornyl acrylate (IBXA), 10 parts by mass of monomers: dimethylacrylamide (DMAA), and 15 parts by mass of monomers: 4 parts by mass of photopolymerization initiator: 2,2-dimethoxy-1,2-diphenylethane-1-one (Omnirad651).

[0057] (Comparative Example 4) The composition was prepared by blending 25 parts by mass of polymer with 40 parts by mass of monomers, isodecyl acrylate (FA-111A), 20 parts by mass of monomers, isobornyl acrylate (IBXA), and 15 parts by mass of 4-hydroxybutyl acrylate (4-HBA), and 4 parts by mass of photopolymerization initiator, 2,2-dimethoxy-1,2-diphenylethane-1-one (Omnirad651).

[0058] [viscosity] The viscosity of each polymer was measured using a viscometer (RE-85R viscometer, manufactured by Toki Sangyo Co., Ltd.) at a set temperature of 60°C, a cone rotor of 3°×R14, and a rotation speed of 0.5-5 rpm. The viscosity of each composition was measured using similar equipment at a set temperature of 25°C, a cone rotor of 1°34'×R24, and a rotation speed of 100 rpm.

[0059] [Method for making adhesive sheets] An adhesive sheet was prepared using a composition prepared with the specified formulation as described above. Specifically, the composition prepared above was coated onto easy-to-adhere PET: A4360 (film thickness: 50 μm) or heavy-release separator: NS-75-B-500 (film thickness: 75 μm) using a bar coater (No. 44), and an adhesive sheet (film thickness: 50 μm) was prepared by UV curing. The UV curing conditions are as follows. UV irradiation device: UVSYSTEMCS60, manufactured by GSYUASALIGHTING Co., Ltd. UV lamp: Manufactured by GSYUASALIGHTING Co., Ltd., high-pressure mercury lamp Exposure conditions: Illuminance 100 mW / cm², integrated light intensity 3000 mJ / cm² 2 (250mJ·cm 2 (x 12 times)

[0060] [evaluation] The following evaluations were performed using the obtained adhesive sheets. The results are shown in Tables 1-3.

[0061] [Peel strength] The prepared adhesive sheet (easy-adhesion PET) was cut into strips 25 mm wide. The adhesive layer side was then pressed and attached to glass using a 2 kg rubber roller with two passes. After standing at room temperature for 1 hour, it was mounted on a Shimadzu Autograph AG-X / R, and the 180-degree peel strength (N / 25 mm) was measured at a peeling speed of 300 mm / min and a measurement temperature of 25°C or 60°C.

[0062] [Measurement of tan δ] Viscoelasticity was evaluated using a viscoelasticity measuring device (TA Instruments, product name: DHR-2) with an 8mm disposable rotor. The gap between the stage and rotor was 400±100μm, the frequency was 1Hz, and the displacement was 1%. For the measurements, a 400μm±100μm film made by stacking adhesive sheets (heavy-release separators) was punched out into a cylindrical shape with a diameter of 7mm.

[0063] [Creep test] Two stainless steel plates (70mm wide x 75mm long) were bonded together using the adhesive layer of an adhesive sheet cut to a size of 25mm wide and 25mm long, with the 25mm length overlapping portion. The test specimens were suspended in a dryer at 40°C or 60°C, and a 100g weight was suspended from the iron plate below. Measurement was taken until the adhesive surface peeled off.

[0064] The evaluation criteria for creep testing are as follows: A: No misalignment or less than 5mm B: The misalignment is greater than 5mm C: Falling

[0065] [Table 1]

[0066] [Table 2]

[0067] [Table 3]

[0068] Examples 1 to 8 showed good results in both peel strength at 60°C and creep tests at 40°C, demonstrating that photocurable compositions with good creep resistance and high-temperature peel strength can be obtained.

Claims

1. A polymer (A) having a radical polymerizable group and an isocyanate group added to it, and having a weight-average molecular weight of 10,000 to 50,000, A photocurable composition comprising monoma (B), The amount of the compound having the radical polymerizable group and the isocyanate group added is 2% by mass or less relative to the polymer (A). The monomer (B) is a photocurable composition comprising nitrogen-containing monomer (b1) in an amount of 20 to 50% by mass relative to the total amount of polymer (A) and monomer (B).

2. The photocurable composition according to claim 1, wherein the monomer (B) further comprises monomer (b2) having an alkyl group having 4 or more carbon atoms.

3. The photocurable composition according to claim 1 or 2, wherein the compound having the radical polymerizable group and the isocyanate group is a compound having a (meth)acryloyl group and the isocyanate group.

4. The photocurable composition according to claim 1 or 2, wherein the polymer A has radical polymerizable groups, and the radical polymerizable groups are bonded to the main chain via urethane bonds.

5. The photocurable composition according to claim 1 or 2, wherein the polymer (A) has a hydroxyalkyloxycarbonyl group.

6. The photocurable composition according to claim 1 or 2, wherein the weight-average molecular weight of polymer A is 10,000 to 40,000.

7. The photocurable composition according to claim 1 or 2, wherein the amount of compound having the radical polymerizable group and the isocyanate group added is 0.001 to 1% by mass relative to the polymer (A).

8. The photocurable composition according to claim 1 or 2, wherein the amount of the nitrogen-containing monomer (b1) is 20 to 30% by mass relative to the total amount of polymer (A) and monomer (B).

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