Photocurable resin composition and cured product thereof

Abstract

The present disclosure provides a means for obtaining a photocurable resin composition that is capable of maintaining a low curing shrinkage rate while realizing adhesive strength with respect to a cured product and reactivity with short-term curing. The present disclosure relates to a photocurable resin composition containing components (A) to (E).　Component (A) is (A-1) a urethane (meth)acrylate having a bisphenol skeleton and / or (A-2) a urethane (meth)acrylate having a polybutadiene skeleton.　Component (B) is a (meth)acrylamide having a heterocyclic structure. Component (C) is a (meth)acrylamide having a specific structure. Component (D) is a (meth)acrylate having a fluorene skeleton. Component (E) is a photoinitiator.

Description

Photocurable resin composition and cured product thereof

[0001] The present invention relates to a photocurable resin composition and a cured product thereof.

[0002] Conventionally, photocurable resin compositions have been used as adhesives and potting agents, and photocurable (meth)acrylic resins are known as photocurable resin compositions. However, photocurable (meth)acrylic resins have a large cure shrinkage rate, which causes deformation of the cured product during curing, resulting in the formation of voids that can cause the cured product to peel off from the substrate. In response to this problem, a method is known in which a urethane acrylate having a polybutadiene skeleton is used to reduce the cure shrinkage rate, as disclosed in Japanese Patent Laid-Open Publication No. 2003-073429.

[0003] However, with conventional techniques, there are problems in that lowering the cure shrinkage rate reduces the reaction rate in short-time curing, causing the physical properties of the cured product to change over time, and there are also problems in that lowering the cure shrinkage rate reduces the adhesive strength of the cured product, making it difficult to achieve both a good cure shrinkage rate and other physical properties.

[0004] As a result of extensive research, the present inventors discovered a method for producing a photocurable resin composition that can achieve both high adhesive strength of the cured product and a high reaction rate in short curing time while keeping the cure shrinkage rate low, and thus completed the present invention.

[0005] The gist of the present invention will now be described.

[0006] One aspect of the present invention that can achieve at least one of the above-mentioned objects relates to the following item [1]. [1] A photocurable resin composition comprising the following components (A) to (E): Component (A): (A-1) a urethane (meth)acrylate having a bisphenol skeleton and / or (A-2) a urethane (meth)acrylate having a polybutadiene skeleton; Component (B): a (meth)acrylamide having a heterocyclic structure; Component (C): a (meth)acrylamide represented by the following general formula 1, wherein R １ represents a methyl group or a hydrogen atom, R ２ and R ３each independently represents an alkyl group having 1 to 5 carbon atoms or a hydrogen atom; component (D): a (meth)acrylate having a fluorene skeleton; component (E): a photoinitiator.

[0007] The present invention also encompasses the following embodiments [2] to

[12] as non-limiting examples of preferred embodiments. [2] The photocurable resin composition according to [1], wherein (A-1) is a urethane (meth)acrylate having a bisphenol skeleton and a polyether skeleton. [3] The photocurable resin composition according to [1] or [2], wherein component (A) is a urethane (meth)acrylate having a bisphenol skeleton and a polyether skeleton. [4] The photocurable resin composition according to [1] or [2], wherein the polybutadiene skeleton is a hydrogenated polybutadiene skeleton. [5] The photocurable resin composition according to any of [1] to [4], wherein the bisphenol skeleton is not a hydrogenated bisphenol skeleton. [6] The photocurable resin composition according to any of [1] to [5], wherein component (B) is a (meth)acrylamide having a morpholine skeleton. [7] The photocurable resin composition according to any of [1] to [6], wherein component (B) is 4-acryloylmorpholine. [8] The photocurable resin composition according to any one of [1] to [7], wherein the total amount of the component (B) and the component (C) is 1 to 50 mass% based on the total photocurable resin components. [9] The photocurable resin composition according to any one of [1] to [8], wherein the content of the component (D) is 1 to 50 mass% based on the total photocurable resin components.

[10] The photocurable resin composition according to any one of [1] to [8], wherein the content of the component (D) is 1 to 50 mass% based on the total photocurable resin components.

[11] The photocurable resin composition according to any one of [1] to [8], wherein the content of the component (D) is 1 to 50 mass% based on the total photocurable resin components.

[12] The photocurable resin composition according to any one of [1] to [8], wherein the total amount of the component (B) and the component (C) is 1 to 50 mass% based on the total photocurable resin components. ２

[10] The photocurable resin composition according to any one of [1] to [9], which has a cure shrinkage of 6.5% or less when cured at room temperature.

[11] The photocurable resin composition according to any one of [1] to

[10] , which is used for casting.

[12] A cured product obtained by curing the photocurable resin composition according to any one of [1] to

[11] .

[0008] The present invention will be described in detail below. Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the following embodiments and can be modified in various ways within the scope of the claims. The embodiments described in this specification can be combined in any manner to form other embodiments.

[0009] In this specification, "X to Y" is used to mean that the numerical values ​​(X and Y) written before and after it are included as the lower limit and upper limit, and means "at least X but not more than Y."

[0010] As used herein, the term (meth)acrylic refers to both acrylic and methacrylic. As used herein, the term (meth)acryloyl refers to both acryloyl and methacryloyl. As used herein, the term (meth)acrylate refers to both acrylate and methacrylate.

[0011] As used herein, "A and / or B" means that each of A and B is included, as well as any combination thereof.

[0012] As used herein, the term "photocurable resin component" refers to components (A) to (D), an optional (meth)acrylate monomer, and an optional (meth)acrylate oligomer. The photocurable resin composition according to some embodiments does not include the optional (meth)acrylate oligomer, and the photocurable resin component may consist solely of components (A) to (D) and the optional (meth)acrylate monomer. The photocurable resin composition according to some embodiments does not include the optional (meth)acrylate monomer, and does not include the optional (meth)acrylate oligomer, and the photocurable resin component may consist solely of components (A) to (D).

[0013] In this specification, the term "oligomer" refers to a polymer in which two to several tens of repeating units (monomer units) are repeated. Preferred examples of the range of the number of repeating units include 2 to 99, 2 to 90, 2 to 80, 2 to 70, 2 to 60, 2 to 50, 2 to 40, 2 to 30, 2 to 20, and 2 to 10.

[0014] In this specification, the term "(meth)acrylate oligomer" refers to a polymer in which two to several tens of repeating units (monomer units) (including repeating units other than (meth)acrylate monomers) are repeated. That is, when the (meth)acrylate oligomer contains only repeating units of (meth)acrylate monomers as repeating units, the term "(meth)acrylate oligomer" refers to a polymer in which two to several tens of repeating units of the (meth)acrylate oligomer (number of monomer units) are repeated. Furthermore, when the (meth)acrylate oligomer contains repeating units other than the (meth)acrylate monomers, the term "(meth)acrylate oligomer" refers to a polymer in which two to several tens of repeating units (monomer units) (the repeating units include repeating units of the (meth)acrylate oligomer as well as repeating units other than the (meth)acrylate monomers) are repeated. Preferred examples of the range of the number of repeating units of the (meth)acrylate oligomer (including repeating units other than the (meth)acrylate monomers) are the same as those described above for the oligomer.

[0015] One aspect of the present invention relates to a photocurable resin composition comprising the following components (A) to (E): component (A): (A-1) a urethane (meth)acrylate having a bisphenol skeleton and / or (A-2) a urethane (meth)acrylate having a polybutadiene skeleton; component (B): a (meth)acrylamide having a heterocyclic structure; component (C): a (meth)acrylamide represented by the general formula 1 described below, wherein in the general formula 1 described below, R １ represents a methyl group or a hydrogen atom, R ２ and R ３ each independently represents an alkyl group having 1 to 5 carbon atoms or a hydrogen atom; component (D): a (meth)acrylate having a fluorene skeleton; component (E): a photoinitiator.

[0016] According to this aspect, it is possible to provide a photocurable resin composition that can achieve both high adhesive strength of the cured product and a high reaction rate in short-time curing while keeping the cure shrinkage rate low.

[0017] <Component (A)> The component (A) that can be used in the present invention is (A-1) a urethane (meth)acrylate having a bisphenol skeleton and / or (A-2) a urethane (meth)acrylate having a polybutadiene skeleton. It is preferable that both (A-1) and (A-2) are oligomers. The component (A) may be a single type, or two or more types may be used in combination. The component (A-1) may be a single type, or two or more types may be used in combination. The component (A-2) may be a single type, or two or more types may be used in combination. The component (A) may contain either (A-1) or (A-2), or both. The component (A) may be (A-1), (A-2), or both. The component (A) may be (A-1). The component (A) may be (A-2). In terms of excellent reactivity in short-time curing, it is preferable that component (A) contains (A-1), and in terms of superior adhesive strength of the cured product, it is preferable that component (A) contains (A-2). Since component (A) is particularly preferable to contain (A-1), it is more excellent in reactivity, in that the physical properties of the cured product are less likely to change over time after curing. The bisphenol skeleton referred to here refers to either a so-called bisphenol skeleton or a hydrogenated bisphenol skeleton, or both a so-called bisphenol skeleton and a hydrogenated bisphenol skeleton. The polybutadiene skeleton referred to here refers to either a so-called polybutadiene skeleton or a hydrogenated polybutadiene skeleton, or both a so-called polybutadiene skeleton and a hydrogenated polybutadiene skeleton. It is preferable that the bisphenol skeleton is not a hydrogenated bisphenol skeleton. The polybutadiene skeleton preferably contains a hydrogenated polybutadiene skeleton, and the polybutadiene skeleton is preferably a hydrogenated polybutadiene skeleton.

[0018] When a (meth)acrylate contains both a bisphenol skeleton and a polybutadiene skeleton, the (meth)acrylate is treated as falling under (A-1). Therefore, (A-2) does not have a bisphenol skeleton. It is preferable that (A-1) does not have a polybutadiene skeleton.

[0019] Examples of the bisphenol skeleton include a structure derived from a polyol represented by the following general formula 2 and a structure derived from a polyol represented by the following general formula 3. Examples of the bisphenol skeleton include a structure in which hydrogen atoms have been removed from both ends of a polyol represented by the following general formula 2 and a structure in which hydrogen atoms have been removed from both ends of a polyol represented by the following general formula 3. The bisphenol skeleton may be one of the structures exemplified above, or a combination of two or more of the structures exemplified above. The bisphenol skeleton may include at least one structure selected from the group consisting of the structures exemplified above. The bisphenol skeleton may be a structure in which hydrogen atoms have been removed from both ends of a polyol represented by the following general formula 2.

[0020] Examples of the polybutadiene skeleton include a structure derived from (a2-1) described below. The polybutadiene skeleton is preferably contained in the molecule of (A-2) as a structure obtained by removing hydrogen atoms from both ends of (a2-1). Examples of the polybutadiene skeleton include a so-called polybutadiene skeleton and a hydrogenated polybutadiene skeleton. The polybutadiene skeleton may be one of the structures exemplified above, or a combination of two or more of the structures exemplified above. The polybutadiene skeleton may include at least one structure selected from the group consisting of the structures exemplified above. The polybutadiene skeleton may be a hydrogenated polybutadiene skeleton.

[0021] (A-1) is preferably synthesized from (a1-1) to (a1-3) described below. The weight-average molecular weight of (A-1) is not particularly limited, but from the viewpoint of obtaining a composition with a lower cure shrinkage rate, it is preferably 1,000 to 50,000, more preferably 10,000 to 45,000, and particularly preferably 11,000 to 20,000. Here, the weight-average molecular weight refers to a value measured by gel permeation chromatography (GPC) using polystyrene as a standard substance. When two or more compounds are used as (A-1), the weight-average molecular weight refers to the weight-average molecular weight of each individual compound. From the viewpoint of achieving a superior cure shrinkage rate and a superior reactivity rate in short-time curing, (A-1) preferably contains 1 to 4 (meth)acrylic groups ((meth)acryloyl groups) per molecule, (A-1) more preferably contains 2 to 4 (meth)acrylic groups ((meth)acryloyl groups) per molecule, and (A-1) particularly preferably contains 2 (meth)acrylic groups ((meth)acryloyl groups) per molecule. (A-1) preferably contains 1 to 4 (meth)acryloyloxy groups per molecule, (A-1) more preferably contains 2 to 4 (meth)acryloyloxy groups per molecule, and (A-1) particularly preferably contains 2 (meth)acryloyloxy groups per molecule. (A-1) preferably contains a methacryloyl group per molecule, more preferably contains a methacryloyloxy group per molecule, and particularly preferably contains two methacryloyloxy groups per molecule. (A-1) is preferably a urethane methacrylate having a bisphenol skeleton. For example, (A-1) may be a urethane (meth)acrylate oligomer having a bisphenol skeleton, or a urethane methacrylate oligomer having a bisphenol skeleton. (A-1) particularly preferably contains two methacryloyloxy groups per molecule.

[0022] (a1-1) is a polyol having a structure represented by the following general formula 2 or the following general formula 3. (a1-1) may be a polyol having a structure represented by the following general formula 2, or may be a polyol having a structure represented by the following general formula 3. As (a1-1), a polyol having a structure represented by the following general formula 2 and a polyol having a structure represented by the following general formula 3 may be used in combination. In general formulas 2 and 3, R ４ and R ５ Each of R is an alkylene group (also known as a divalent alkylene group) having one or more carbon atoms, and m and n are integers of 0 or more. ４ and R ５ In consideration of the cure shrinkage, in general formula 2 and general formula 3, R ４ is preferably an alkylene group having 1 to 5 carbon atoms (also known as a divalent alkylene group), and R ５ is preferably an alkylene group (also known as a divalent alkylene group) having 1 to 3 carbon atoms, and n and m are each preferably an integer of 0 to 5, and m and n may be the same or different. n and m may each independently be an integer of 1 or more, or may be an integer of 1 to 5. R ５ It is particularly preferable that R has 3 carbon atoms (also known as a divalent alkylene group). These may be used alone or in combination. ５ is preferably an alkylene group having 3 carbon atoms (also known as a divalent alkylene group), and is preferably a dimethylmethylene group (*-C(CH ３ ) ２ -*), where * represents a bonding site with an adjacent atom.

[0023]

[0024]

[0025] The bisphenol skeleton contained in (A-1) is particularly preferably a bisphenol A skeleton. Examples of the bisphenol A skeleton include those represented by the above general formula 2 and having the structure R ５The bisphenol A skeleton is represented by the general formula 2 above, and a structure in which hydrogen atoms are removed from both ends of a polyol in which R is a dimethylmethylene group can be given. ５ may be a structure in which hydrogen atoms are removed from both ends of a polyol in which R is a dimethylmethylene group, and is represented by the above general formula (2), ４ is an alkylene group having one or more carbon atoms (also known as a divalent alkylene group), and R ５ is a dimethylmethylene group, m is an integer of 1 or more, and n is an integer of 1 or more, and a structure in which hydrogen atoms have been removed from both ends of a polyol.

[0026] (a1-2) is a polyisocyanate compound. A polyisocyanate compound refers to a compound having two or more isocyanate groups in the molecule. In consideration of the adhesive strength of the cured product, a compound having two isocyanate groups in the molecule is preferable. Specific examples of polyisocyanate compounds include aromatic polyisocyanates, alicyclic polyisocyanates, and aliphatic polyisocyanates. Examples of aromatic polyisocyanates include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, tetramethylxylylene diisocyanate, diphenylmethane diisocyanate, naphthalene-1,5-diisocyanate, and triphenylmethane triisocyanate. Examples of alicyclic polyisocyanates include isophorone diisocyanate, bis(4-isocyanatocyclohexyl)methane, 1,3-bis(isocyanatomethyl)cyclohexane, 1,4-bis(isocyanatomethyl)cyclohexane, norbornane diisocyanate, and bicycloheptane triisocyanate. Examples of aliphatic polyisocyanates include hexamethylene diisocyanate, 1,3,6-hexamethylene triisocyanate, and 1,6,11-undeca triisocyanate. These may be used alone or in combination. From the viewpoint of adhesive strength of the cured product, (a1-2) is preferably isophorone diisocyanate or tolylene diisocyanate. From the viewpoint of adhesive strength of the cured product, (a1-2) is particularly preferably isophorone diisocyanate, 2,4-tolylene diisocyanate, or 2,6-tolylene diisocyanate. (a1-2) may be 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, or a combination thereof.

[0027] (a1-3) is a (meth)acrylate containing a hydroxyl group in the molecule. As (a1-3), a (meth)acrylate containing one or more hydroxyl groups in one molecule can be used. As (a1-3), a compound containing one hydroxyl group and one (meth)acryloyloxy group in the molecule may be used, or a compound containing one hydroxyl group and one methacryloyloxy group in the molecule may be used. Examples of (meth)acrylates containing a hydroxyl group in the molecule include 2-hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, mono(meth)acrylates of dihydric alcohols, mono(meth)acrylates of trihydric alcohols, and di(meth)acrylates of trihydric alcohols. With regard to the mono(meth)acrylates of dihydric alcohols, examples of the dihydric alcohols include ethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, and polyethylene glycol. With regard to the mono(meth)acrylates of trihydric alcohols and di(meth)acrylates of trihydric alcohols, examples of the trihydric alcohols include trimethylolethane, trimethylolpropane, and glycerin. These (meth)acrylates containing a hydroxyl group in the molecule may be used alone or in combination. From the viewpoint of adhesive strength of the cured product, it is particularly preferable that (a1-3) be at least one selected from the group consisting of 2-hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate.

[0028] In order to obtain a composition with a lower cure shrinkage rate, it is preferable that (A-1) further has a polyether skeleton different from the skeleton derived from (a1-1). (A-1) preferably contains a urethane (meth)acrylate having a bisphenol skeleton and a polyether skeleton, and (A-1) is more preferably a urethane (meth)acrylate having a bisphenol skeleton and a polyether skeleton. Component (A) is even more preferably a urethane (meth)acrylate having a bisphenol skeleton and a polyether skeleton. Examples of polyether skeletons include a structure derived from (a1-4) described below. A urethane (meth)acrylate having a bisphenol skeleton and a polyether skeleton can be synthesized, for example, by adding a polyol having a polyether skeleton (a1-4) to (a1-1) to (a1-3) during synthesis.

[0029] (a1-4) is a polyol having a polyether skeleton. However, in this specification, (a1-4) is treated as excluding (a1-1): a polyol having a structure represented by the above general formula 2 or 3. Examples of polyether skeletons include a structure obtained by removing hydrogen atoms from at least two hydroxyl groups of (a1-4). The polyether skeleton may be, for example, a structure obtained by removing hydrogen atoms from at least two hydroxyl groups of (a1-4). Any polyether polyol having two or more hydroxyl groups in the molecule can be used as (a1-4). The alkylene oxide group of the polyether polyol having two or more hydroxyl groups in the molecule may contain an alkylene group (also known as a divalent alkylene group) having one or more carbon atoms. Specific examples of the alkylene oxide group include a methylene oxide group (*-CH ２ -O-*), ethylene oxide group (*-CH ２ -CH ２ -O-*), propylene oxide group (*-CH ２ -CH ２ (CH ３ )-O-*), trimethylene oxide group (*-CH ２ -CH ２ -CH ２-O-*), butylene oxide group (*-CH ２ -CH ２ (C ２ H ５ )-O-*), tetramethylene oxide group (*-CH ２ -CH ２ -CH ２ -CH ２ -O-*). * represents a bonding site with an adjacent atom. However, the alkylene oxide group is not limited to these. (a1-4) may contain one type of these alkylene oxide groups alone, or two or more types of these alkylene oxide groups. Furthermore, the alkylene group (also known as a divalent alkylene group) in the alkylene oxide group may be structurally linear or branched. From the viewpoint of obtaining a composition with a lower cure shrinkage rate, (a1-4) is preferably a polyether polyol, more preferably a linear polyether glycol having primary hydroxy groups at both ends, and most preferably polytetramethylene glycol (also known as polytetramethylene ether glycol). (a1-1) and (a1-4) are preferably used in combination, and the weight ratio (mass ratio) of the components can be 9:1 to 1:9.

[0030] The polyether skeleton contained in (A-1) is not particularly limited. Examples of the polyether skeleton contained in (A-1) include a polymethylene glycol skeleton, a polyethylene glycol skeleton, a polypropylene glycol skeleton, a polytrimethylene glycol skeleton, a polybutylene glycol skeleton, and a polytetramethylene glycol skeleton. The polyether skeleton contained in (A-1) may be one of the skeletons exemplified above, or a combination of two or more of the skeletons exemplified above. The polyether skeleton contained in (A-1) preferably contains at least one skeleton selected from the group consisting of the skeletons exemplified above, and the polyether skeleton contained in (A-1) more preferably contains a polytetramethylene glycol skeleton. The polyether skeleton contained in (A-1) is particularly preferably a polytetramethylene glycol skeleton.

[0031] (A-1) is preferably a urethane methacrylate having a bisphenol skeleton and a polyether skeleton. For example, (A-1) may be a urethane (meth)acrylate oligomer having a bisphenol skeleton and a polyether skeleton, or a urethane methacrylate oligomer having a bisphenol skeleton and a polyether skeleton.

[0032] The synthesis method for component (A-1) is not particularly limited, and known methods can be used. First, regarding the synthesis method for the urethane prepolymer, an example of the synthesis method for the urethane prepolymer is a synthesis method in which a mixture of (a1-1) and (a1-4), which are polyol compounds having two or more hydroxyl groups in the molecule, is reacted with (a1-2), which is an isocyanate compound having two or more isocyanate groups in the molecule. The synthesis method for the urethane prepolymer may be, for example, a synthesis method in which an isocyanate compound is added to either (a1-1) or (a1-4), and the remaining component (polyol compound) is then added stepwise. Here, the molar ratio of polyol compound to isocyanate compound is preferably 3:1 to 1:3, and more preferably 2:1 to 1:2. During synthesis, the urethane prepolymer can also be obtained by reaction in a diluent. Next, the remaining isocyanate groups in the resulting urethane prepolymer are reacted with a sufficient amount of (a1-3): a (meth)acrylate containing a hydroxyl group in the molecule (a (meth)acrylate containing at least one hydroxyl group in the molecule) to synthesize a urethane (meth)acrylate. Examples of catalysts used in the synthesis include lead oleate, tetrabutyltin, antimony trichloride, triphenylaluminum, trioctylaluminum, dibutyltin dilaurate, copper naphthenate, zinc naphthenate, zinc octoate, zinc octenoate, zirconium naphthenate, cobalt naphthenate, tetra-n-butyl-1,3-diacetyloxydistannoxane, triethylamine, 1,4-diaza[2,2,2]bicyclooctane, and N-ethylmorpholine. Among these, dibutyltin dilaurate, zinc naphthenate, zinc octoate, and / or zinc octenoate are preferably used because they produce highly reactive urethane (meth)acrylates. These catalysts are preferably used in an amount of 0.0001 to 10 parts by mass per 100 parts by mass of the total amount of the reactants. The reaction temperature may usually be 10 to 100°C, and is particularly preferably 30 to 90°C.Before starting the synthesis of (A-1), a solvent and / or a (meth)acrylate monomer (described later) may be used as a diluent. Examples of the solvent include methyl ethyl ketone and methoxyphenol. However, it is preferable to use (A-1) after volatilizing the solvent.

[0033] (A-2) is preferably synthesized from the following (a2-1) to (a2-3). The weight-average molecular weight of (A-2) is not particularly limited, but from the viewpoint of obtaining a composition with a lower cure shrinkage rate, it is preferably 5,000 to 50,000, more preferably 10,000 to 45,000, and particularly preferably 11,000 to 30,000. Here, the weight-average molecular weight refers to a value measured by gel permeation chromatography (GPC) using polystyrene as a standard substance. When two or more compounds are used as (A-2), the weight-average molecular weight refers to the weight-average molecular weight of each individual compound. From the viewpoint of achieving superior cure shrinkage and adhesive strength of the cured product, (A-2) preferably contains 1 to 4 (meth)acrylic groups ((meth)acryloyl groups) per molecule, (A-2) more preferably contains 2 to 4 (meth)acrylic groups ((meth)acryloyl groups) per molecule, and (A-2) most preferably contains 2 (meth)acrylic groups ((meth)acryloyl groups) per molecule. (A-2) preferably contains 1 to 4 (meth)acryloyloxy groups per molecule, (A-2) more preferably contains 2 to 4 (meth)acryloyloxy groups per molecule, and (A-2) particularly preferably contains 2 (meth)acryloyloxy groups per molecule. (A-2) preferably contains an acryloyl group per molecule, more preferably contains an acryloyloxy group per molecule, and particularly preferably contains two acryloyloxy groups per molecule. (A-2) is preferably a urethane acrylate having a polybutadiene skeleton, and more preferably a urethane acrylate having a hydrogenated polybutadiene skeleton. For example, (A-2) may be a urethane (meth)acrylate oligomer having a polybutadiene skeleton, or a urethane acrylate oligomer having a polybutadiene skeleton. For example, (A-2) may be a urethane (meth)acrylate oligomer having a hydrogenated polybutadiene skeleton, or a urethane acrylate oligomer having a hydrogenated polybutadiene skeleton. (A-2) particularly preferably contains two acryloyloxy groups per molecule.

[0034] (a2-1) may be a compound having a so-called polybutadiene skeleton or a hydrogenated polybutadiene skeleton with hydroxyl groups at at least two terminals. (a2-1) may also be a compound having a structure in which hydrogen atoms are bonded to at least two terminals of a polybutadiene or hydrogenated polybutadiene, directly or via a linking group. (a2-1) is not particularly limited as long as it has a so-called polybutadiene skeleton and / or a hydrogenated polybutadiene skeleton. The weight-average molecular weight of (a2-1) is not particularly limited, but is preferably 500 to 5,000, more preferably 1,000 to 4,500, and particularly preferably 2,000 to 4,000, in order to obtain a composition with a lower cure shrinkage rate. These may be used alone or in combination. The linking group is not particularly limited, but is preferably a divalent group, more preferably an alkylene group (also known as a divalent alkylene group). (a2-1) may contain a compound having a structure in which hydrogen atoms are bonded to at least two terminals of a hydrogenated polybutadiene directly or via a linking group, or (a2-1) may contain a polyol in which hydroxyl groups are bonded to two terminals of a hydrogenated polybutadiene via an alkylene group (also known as a divalent alkylene group). (a2-1) may be a compound having a structure in which hydrogen atoms are bonded to at least two terminals of a hydrogenated polybutadiene directly or via a linking group, or may be a polyol in which hydroxyl groups are bonded to two terminals of a hydrogenated polybutadiene via an alkylene group (also known as a divalent alkylene group).

[0035] (a2-2) is a polyisocyanate compound. A polyisocyanate compound refers to a compound having two or more isocyanate groups in the molecule. In consideration of the adhesive strength of the cured product, the polyisocyanate compound is preferably a compound having two isocyanate groups in the molecule. Specific examples of polyisocyanate compounds include aromatic polyisocyanates, alicyclic polyisocyanates, and aliphatic polyisocyanates. Examples of aromatic polyisocyanates include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, tetramethylxylylene diisocyanate, diphenylmethane diisocyanate, naphthalene-1,5-diisocyanate, and triphenylmethane triisocyanate. Examples of alicyclic polyisocyanates include isophorone diisocyanate, bis(4-isocyanatocyclohexyl)methane, 1,3-bis(isocyanatomethyl)cyclohexane, 1,4-bis(isocyanatomethyl)cyclohexane, norbornane diisocyanate, and bicycloheptane triisocyanate. Examples of aliphatic polyisocyanates include hexamethylene diisocyanate, 1,3,6-hexamethylene triisocyanate, and 1,6,11-undeca triisocyanate. These may be used alone or in combination. From the viewpoint of adhesive strength of the cured product, (a2-2) is preferably isophorone diisocyanate or tolylene diisocyanate. From the viewpoint of adhesive strength of the cured product, (a2-2) is particularly preferably isophorone diisocyanate, 2,4-tolylene diisocyanate, or 2,6-tolylene diisocyanate.

[0036] (a2-3) is a (meth)acrylate containing a hydroxyl group in the molecule. As (a2-3), a (meth)acrylate containing one or more hydroxyl groups in one molecule can be used. As (a1-3), a compound containing one hydroxyl group and one (meth)acryloyloxy group in the molecule may be used, or a compound containing one hydroxyl group and one acryloyloxy group in the molecule may be used. Examples of (meth)acrylates containing a hydroxyl group in the molecule include 2-hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, mono(meth)acrylates of dihydric alcohols, mono(meth)acrylates of trihydric alcohols, and di(meth)acrylates of trihydric alcohols. Examples of dihydric alcohols include ethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, and polyethylene glycol. Examples of trihydric alcohols include trimethylolethane, trimethylolpropane, and glycerin. These (meth)acrylates containing a hydroxyl group in the molecule may be used alone or in combination. From the viewpoint of adhesive strength of the cured product, it is particularly preferable that (a2-3) be at least one selected from hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate.

[0037] The synthesis method for component (A-2) is not particularly limited, and known methods can be used. First, regarding the synthesis of the urethane prepolymer, an example of the synthesis of the urethane prepolymer includes a synthesis method in which (a2-1), a polyol compound having two or more hydroxyl groups in its molecule, is reacted with (a2-2), an isocyanate compound having two or more isocyanate groups in its molecule. During synthesis, the reaction can be carried out in a diluent to obtain a urethane prepolymer. Next, the remaining isocyanate groups in the obtained urethane prepolymer are reacted with a sufficient amount of (a2-3), a (meth)acrylate containing a hydroxyl group in its molecule (a (meth)acrylate containing at least one or more hydroxyl groups in its molecule), to synthesize a urethane (meth)acrylate. Alternatively, a different synthesis method may be used, for example, by adding (a2-3) to one of the isocyanate groups in (a2-2), followed by adding (a2-1). Here, the molar ratio of (a2-2) to (a2-1) and the molar ratio of (a2-3) to (a2-1) are preferably such that (a2-1) is 0.5 to 4 to 1, and more preferably (a2-1) is 1 to 3 to 1. Examples of catalysts used in the synthesis include lead oleate, tetrabutyltin, antimony trichloride, triphenylaluminum, trioctylaluminum, dibutyltin dilaurate, copper naphthenate, zinc naphthenate, zinc octoate, zinc octenoate, zirconium naphthenate, cobalt naphthenate, tetra-n-butyl-1,3-diacetyloxydistannoxane, triethylamine, 1,4-diaza[2,2,2]bicyclooctane, and N-ethylmorpholine. Among these, dibutyltin dilaurate, zinc naphthenate, zinc octoate, and / or zinc octenoate are preferably used because they produce highly reactive urethane (meth)acrylates. These catalysts are preferably used in an amount of 0.0001 to 10 parts by mass per 100 parts by mass of the total amount of reactants. The reaction temperature may usually be 10 to 100°C, and is particularly preferably 30 to 90°C.Before starting the synthesis of (A-2), a solvent and / or a (meth)acrylate monomer (described later) may be used as a diluent. Examples of the solvent include methyl ethyl ketone and methoxyphenol. However, it is preferable to use (A-2) after volatilizing the solvent.

[0038] The content of component (A) is not particularly limited. The content of component (A) is preferably 10 to 90% by mass, more preferably 20 to 80% by mass, and particularly preferably 30 to 75% by mass, based on the total photocurable resin components. When the content of component (A) is 10% by mass or more based on the total photocurable resin components, a composition with a lower cure shrinkage rate can be obtained. When the content of component (A) is 90% by mass or less based on the total photocurable resin components, the adhesive strength of the cured product and the reactivity in short-term curing are superior. The content of component (A) may be 30 to 55% by mass based on the total photocurable resin components. The content of component (A) may be more than 55% by mass and 75% by mass or less based on the total photocurable resin components. As described above, the photocurable resin components refer to component (A), components (B) to (D) described below, optional (meth)acrylate monomers, and optional (meth)acrylate oligomers. Therefore, the total photocurable resin components refers to the total mass of the photocurable resin components, i.e., the total mass of the (A), (B), (C), (D) components, optional (meth)acrylate monomers, and optional (meth)acrylate oligomers. When two or more compounds are used as the (A) component, the amount of the (A) component refers to the total amount thereof. When two or more compounds are used as the (B) component, the amount of the (B) component refers to the total amount thereof. When two or more compounds are used as the (C) component, the amount of the (C) component refers to the total amount thereof. When two or more compounds are used as the (D) component, the amount of the (D) component refers to the total amount thereof. When two or more compounds are used as the optional (meth)acrylate monomers, the amount of the optional (meth)acrylate monomers refers to the total amount thereof. When two or more compounds are used as the optional (meth)acrylate oligomers, the amount of the optional (meth)acrylate oligomers refers to the total amount thereof.

[0039] <Component (B)> The component (B) that can be used in the present invention is a (meth)acrylamide having a heterocyclic structure. In this specification, the term "heterocycle" refers to a cyclic structure containing two or more different elements that constitute the ring. The elements that constitute the ring are not particularly limited as long as they contain two or more different elements. The component (B) may be used alone or in combination. From the viewpoint of achieving superior adhesive strength of the cured product and superior reactivity in short-time curing, the elements that constitute the ring are preferably carbon and heteroatoms, and more preferably carbon, oxygen, and / or nitrogen. The heterocycle is preferably composed of carbon and heteroatoms, and more preferably carbon, oxygen, and / or nitrogen. Examples of heterocycles include those with a 3- to 7-membered ring structure. From the viewpoint of achieving superior reactivity in short-time curing, the heterocycle is preferably a 5- or 6-membered ring. The heterocycle may be saturated or unsaturated. From the viewpoint of achieving superior reactivity in short-time curing, the heterocycle is preferably saturated. From the viewpoint of achieving a superior reaction rate in short-term curing, the heterocycle is more preferably a saturated 3- to 7-membered ring, and even more preferably a saturated 5-membered ring or a saturated 6-membered ring. Specific examples of the heterocycle include a pyrrolidine ring, a tetrahydrofuran ring, an imidazolidine ring, an imidazole ring, a triazole ring, an oxazolidine ring, an oxazole ring, a piperidine ring, a tetrahydropyran ring, a piperazine ring, a morpholine ring, an oxazine ring, a dioxane ring, a hexahydro-1,3,5-triazine ring, and a triazine ring. The heterocycle is preferably a piperidine ring, a tetrahydropyran ring, a piperazine ring, a morpholine ring, an oxazine ring, a dioxane ring, or a hexahydro-1,3,5-triazine ring, and most preferably a morpholine ring. The component (B) preferably contains a (meth)acrylamide having at least one skeleton selected from the group consisting of a piperidine ring skeleton, a tetrahydropyran ring skeleton, a piperazine ring skeleton, a morpholine ring skeleton, an oxazine ring skeleton, a dioxane ring skeleton, and a hexahydro-1,3,5-triazine ring skeleton, and more preferably contains a (meth)acrylamide having a morpholine ring skeleton.The component (B) may be a (meth)acrylamide having at least one skeleton selected from the group consisting of a piperidine ring skeleton, a tetrahydropyran ring skeleton, a piperazine ring skeleton, a morpholine ring skeleton, an oxazine ring skeleton, a dioxane ring skeleton, and a hexahydro-1,3,5-triazine ring skeleton, or may be a (meth)acrylamide having a morpholine ring skeleton, or may be an acrylamide having a morpholine ring skeleton.

[0040] Component (B) contains a (meth)acrylamide group. The number of (meth)acrylamide groups in component (B) is not particularly limited, as long as there is one or more per molecule. From the viewpoint of achieving a superior cure shrinkage rate, component (B) preferably contains one to three (meth)acrylamide groups, more preferably one or two, and most preferably only one. From the viewpoint of achieving a superior cure shrinkage rate, component (B) preferably contains one to three (meth)acrylamide groups per molecule, more preferably one or two (meth)acrylamide groups per molecule, and particularly preferably only one (meth)acrylamide group per molecule. The (meth)acrylamide group in component (B) may be present independently of the heterocyclic ring in the molecule. The (meth)acrylamide group in component (B) may be present such that the nitrogen atom constituting the (meth)acrylamide group is included in the heterocyclic ring. Specifically, the nitrogen atom contained in the pyrrolidine ring, imidazolidine ring, imidazole ring, triazole ring, piperidine ring, piperazine ring, morpholine ring, and / or hexahydro-1,3,5-triazine ring may be the same as the nitrogen atom constituting the (meth)acrylamide group. It is particularly preferable that component (B) contains a compound in which the nitrogen atom constituting the (meth)acrylamide group is contained in a heterocycle. It is particularly preferable that component (B) contains an acrylamide group. It is particularly preferable that component (B) contains only one acrylamide group per molecule.

[0041] Specific examples of component (B) include 3-(meth)acryloyl-2-oxazolidinone, 4-(meth)acryloylmorpholine, and 1,3,5-tri(meth)acryloylhexahydro-1,3,5-triazine. These may be used alone or in combination. Among these, 4-(meth)acryloylmorpholine is preferred, and 4-acryloylmorpholine is more preferred, from the viewpoint of achieving a superior reaction rate in short-time curing. Component (B) preferably contains 4-(meth)acryloylmorpholine, and more preferably contains 4-acryloylmorpholine. Component (B) may be 4-(meth)acryloylmorpholine or may be 4-acryloylmorpholine.

[0042] The content of component (B) is not particularly limited. The content of component (B) is preferably 1 to 50 mass%, more preferably 1 to 17 mass%, even more preferably 5 to 15 mass%, and particularly preferably 7.5 to 12.5 mass%, based on the total photocurable resin components. When the content of component (B) is 1 mass% or more based on the total photocurable resin components, the adhesive strength of the cured product and the reactivity in short-term curing are superior. When the content of component (B) is 50 mass% or less based on the total photocurable resin components, a composition with a lower cure shrinkage rate can be obtained. The content of component (B) per 100 parts by mass of component (A) is preferably 5 to 50 parts by mass, more preferably 10 to 35 parts by mass, and particularly preferably 10 to 30 parts by mass. The content of component (B) per 100 parts by mass of component (A) is preferably 5 to 50 parts by mass, more preferably 10 to 35 parts by mass, and particularly preferably 10 to 30 parts by mass. The content of component (B) may be 10 parts by mass or more but less than 20 parts by mass, or may be 20 to 30 parts by mass, per 100 parts by mass of component (A). When two or more compounds are used as component (A), the amount of component (A) represents the total amount of these. When two or more compounds are used as component (B), the amount of component (B) represents the total amount of these. When two or more compounds are used as component (C), the amount of component (C) represents the total amount of these. When two or more compounds are used as component (D), the amount of component (D) represents the total amount of these. When two or more compounds are used as optional (meth)acrylate monomers, the amount of optional (meth)acrylate monomers represents the total amount of these. When two or more compounds are used as optional (meth)acrylate oligomers, the amount of optional (meth)acrylate oligomers represents the total amount of these.

[0043] <Component (C)> The component (C) that can be used in the present invention is a (meth)acrylamide represented by the following general formula 1. The component (C) excludes the component (B). That is, the (meth)acrylamide represented by the following general formula 1 does not have a heterocyclic structure. It can also be said that the component (C) is a (meth)acrylamide-based compound of a specific structure selected from (meth)acrylamides excluding the component (B). In the following general formula 1, R１ represents a methyl group or a hydrogen atom, R ２ and R ３ Each represents an alkyl group having 1 to 5 carbon atoms or a hydrogen atom. ２ and R ３ R each independently represents an alkyl group having 1 to 5 carbon atoms or a hydrogen atom. １ is preferably a hydrogen atom. ２ and R ３ may be the same alkyl group. ２ and R ３ may be alkyl groups with different carbon numbers. ２ and R ３ are each preferably independently a chain alkyl group. ２ and R ３ It is more preferable that both of R are chain alkyl groups. ２ and R ３ may each independently be a methyl group or an ethyl group. ２ and R ３ are preferably the same alkyl groups. ２ and R ３ It is more preferable that both of the above are methyl groups or ethyl groups. The component (C) may be used alone or in combination of two or more.

[0044]

[0045] The number of (meth)acrylamide groups in component (C) is not particularly limited as long as it contains one or more per molecule. From the viewpoint of achieving a better cure shrinkage rate, it is preferable that component (C) contains 1 to 3 (meth)acrylamide groups per molecule, more preferably 1 or 2 per molecule, and particularly preferably only 1 per molecule. It is preferable that component (C) contains an acrylamide group. That is, １ is preferably a hydrogen atom. It is particularly preferred that component (C) contains only one acrylamide group per molecule.

[0046] Specific examples of component (C) include (meth)acrylamide, N-methyl(meth)acrylamide, N-ethyl(meth)acrylamide, N-propyl(meth)acrylamide, N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, and N-methyl-N-ethyl(meth)acrylamide. These may be used alone or in combination. From the viewpoint of achieving a superior reaction rate in short-time curing, component (C) is preferably N,N-dimethyl(meth)acrylamide and / or N,N-diethyl(meth)acrylamide, and more preferably N,N-dimethylacrylamide and / or N,N-diethylacrylamide. Component (C) preferably contains at least one compound selected from the group consisting of the compounds exemplified above. Component (C) more preferably contains N,N-dimethyl(meth)acrylamide and / or N,N-diethyl(meth)acrylamide, and even more preferably contains N,N-dimethylacrylamide and / or N,N-diethylacrylamide. Component (C) may be N,N-dimethyl(meth)acrylamide and / or N,N-diethyl(meth)acrylamide, or may be N,N-dimethylacrylamide and / or N,N-diethylacrylamide. Component (C) may be N,N-dimethylacrylamide. Component (C) may be N,N-diethylacrylamide.

[0047] The content of component (C) is not particularly limited. The content of component (C) is preferably 1 to 50 mass%, more preferably 1 to 17 mass%, even more preferably 5 to 15 mass%, and particularly preferably 7.5 to 12.5 mass%, based on the total photocurable resin components. When the content of component (C) is 1 mass% or more based on the total photocurable resin components, the adhesive strength of the cured product and the reactivity in short-time curing are superior. When the content of component (C) is 50 mass% or less based on the total photocurable resin components, a composition with a lower cure shrinkage rate is obtained. The content of component (C) per 100 parts by mass of component (A) is preferably 5 to 50 parts by mass, more preferably 10 to 35 parts by mass, and particularly preferably 10 to 30 parts by mass. The content of component (C) per 100 parts by mass of component (A) is preferably 5 to 50 parts by mass, more preferably 10 to 35 parts by mass, and particularly preferably 10 to 30 parts by mass. When two or more compounds are used as component (A), the amount of component (A) represents the total amount thereof. When two or more compounds are used as component (B), the amount of component (B) represents the total amount thereof. When two or more compounds are used as component (C), the amount of component (C) represents the total amount thereof. When two or more compounds are used as component (D), the amount of component (D) represents the total amount thereof. When two or more compounds are used as optional (meth)acrylate monomers, the amount of optional (meth)acrylate monomers represents the total amount thereof. When two or more compounds are used as optional (meth)acrylate oligomers, the amount of optional (meth)acrylate oligomers represents the total amount thereof.

[0048] The total amount of components (B) and (C) is not particularly limited. The total amount of components (B) and (C) is preferably 1 to 50% by mass, more preferably 2 to 34% by mass, even more preferably 10 to 30% by mass, and particularly preferably 15 to 25% by mass, based on the total photocurable resin components. When the total amount of components (B) and (C) is 1% by mass or more based on the total photocurable resin components, the adhesive strength of the cured product and the reactivity in short-term curing are superior. When the total amount of components (B) and (C) is 50% by mass or less based on the total photocurable resin components, a composition with a lower cure shrinkage rate can be obtained. The total amount of components (B) and (C) per 100 parts by mass of component (A) is preferably 10 to 100 parts by mass, more preferably 20 to 75 parts by mass, and particularly preferably 20 to 60 parts by mass. The total amount of component (B) and component (C) is preferably 10 to 100 parts by mass, more preferably 20 to 75 parts by mass, and particularly preferably 20 to 60 parts by mass, per 100 parts by mass of component (A). When two or more compounds are used as component (A), the amount of component (A) represents the total amount of these. When two or more compounds are used as component (B), the amount of component (B) represents the total amount of these. When two or more compounds are used as component (C), the amount of component (C) represents the total amount of these. When two or more compounds are used as component (D), the amount of component (D) represents the total amount of these. When two or more compounds are used as optional (meth)acrylate monomers, the amount of optional (meth)acrylate monomers represents the total amount of these. When two or more compounds are used as optional (meth)acrylate oligomers, the amount of optional (meth)acrylate oligomers represents the total amount of these.

[0049] <Component (D)> The component (D) that can be used in the present invention is a (meth)acrylate having a fluorene skeleton. However, the component (D) does not include the component (A). The component (D) does not include a urethane (meth)acrylate having a bisphenol skeleton, and does not include a urethane (meth)acrylate having a polybutadiene skeleton. The component (D) may be used alone or in combination. There are no particular restrictions on the component (D) as long as it is a (meth)acrylate having a fluorene skeleton. In terms of achieving a superior reaction rate in short-term curing, the component (D) preferably contains 1 to 4 (meth)acrylic groups ((meth)acryloyl groups) in the molecule, more preferably the component (D) contains 2 or 3 (meth)acrylic groups ((meth)acryloyl groups) in the molecule, and particularly preferably the component (D) contains 2 (meth)acrylic groups ((meth)acryloyl groups) in the molecule. The component (D) preferably contains 1 to 4 (meth)acryloyloxy groups per molecule, more preferably 2 to 4 (meth)acryloyloxy groups per molecule, and particularly preferably 2 (meth)acryloyloxy groups per molecule. The component (D) preferably contains an acryloyl group per molecule, more preferably acryloyloxy groups per molecule, and particularly preferably 2 acryloyloxy groups per molecule. In terms of superior adhesive strength of the cured product, the component (D) is preferably a (meth)acrylate having a cardo structure and a fluorene skeleton, and more preferably one having a cardo structure in which two aromatic rings are bonded to a fluorene skeleton. Component (D) preferably contains a (meth)acrylate having a cardo structure and a fluorene skeleton, and more preferably contains a (meth)acrylate having a cardo structure in which two aromatic rings are bonded to a fluorene skeleton. Component (D) may be a (meth)acrylate having a cardo structure and a fluorene skeleton, or may be a (meth)acrylate having a cardo structure in which two aromatic rings are bonded to a fluorene skeleton.Component (D) may be an acrylate having a cardo structure and a fluorene skeleton, an acrylate having a cardo structure in which two aromatic rings are bonded to a fluorene skeleton, or an acrylate having a cardo structure in which two aromatic rings are bonded to a fluorene skeleton and containing two acryloyloxy groups in one molecule.

[0050] The component (D) may be a monomer, an oligomer, or a polymer, or two or more of these may be used in combination.

[0051] Specific examples of the component (D) include OGSOL EA-0200, GA-5060P, EA-0300, and GA-2800 (manufactured by Osaka Gas Chemicals Co., Ltd.). These may be used alone or in combination.

[0052] The content of component (D) is not particularly limited. The content of component (D) is preferably 1 to 50 mass%, more preferably 1 to 30 mass%, even more preferably 5 to 25 mass%, and particularly preferably 10 to 20 mass%, based on the total photocurable resin components. When the content of component (D) is within the range of 1 to 50 mass%, based on the total photocurable resin components, the adhesive strength of the cured product and the reactivity in short-term curing are superior. The content of component (D) per 100 parts by mass of component (A) is preferably 5 to 50 parts by mass, more preferably 10 to 45 parts by mass, and particularly preferably 15 to 40 parts by mass. The content of component (D) per 100 parts by mass of component (A) is preferably 5 to 50 parts by mass, more preferably 10 to 45 parts by mass, and particularly preferably 15 to 40 parts by mass. When two or more compounds are used as component (A), the amount of component (A) represents the total amount of these compounds. When two or more compounds are used as the (B) component, the amount of the (B) component represents the total amount thereof. When two or more compounds are used as the (C) component, the amount of the (C) component represents the total amount thereof. When two or more compounds are used as the (D) component, the amount of the (D) component represents the total amount thereof. When two or more compounds are used as the optional (meth)acrylate monomer, the amount of the optional (meth)acrylate monomer represents the total amount thereof. When two or more compounds are used as the optional (meth)acrylate oligomer, the amount of the optional (meth)acrylate oligomer represents the total amount thereof.

[0053] <Component (E)> The component (E) that can be used in the present invention is a photoinitiator. Any component that decomposes upon irradiation with energy rays such as ultraviolet light and / or visible light to generate radical species can be used as the component (E). The component (E) may be used alone or in combination. Examples of the component (E) include acetophenone-based photoinitiators, benzoin-based photoinitiators, benzophenone-based photoinitiators, thioxanthone-based photoinitiators, and acylphosphine oxide-based photoinitiators. These may be used alone or in combination of two or more. The component (E) preferably contains at least one photoinitiator selected from the group consisting of the photoinitiators exemplified above. Because photocurability is improved even with light irradiation at low illuminance or a small cumulative light dose, the component (E) more preferably contains an acylphosphine oxide-based photoinitiator. The component (E) may be an acylphosphine oxide-based photoinitiator.

[0054] Examples of acetophenone-based photoinitiators include diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzyl dimethyl ketal, 4-(2-hydroxyethoxy)phenyl-(2-hydroxy-2-propyl)ketone, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-2-morpholino(4-thiomethylphenyl)propan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone, and 2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanone oligomer, but the acetophenone-based photoinitiator is not limited thereto. These may be used alone or in combination of two or more.

[0055] Examples of benzoin-based photoinitiators include, but are not limited to, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, etc. These may be used alone or in combination of two or more.

[0056] Examples of benzophenone-based photoinitiators include benzophenone, methyl o-benzoylbenzoate, 4-phenylbenzophenone, 4-benzoyl-4'-methyl-diphenyl sulfide, 3,3',4,4'-tetra(t-butylperoxycarbonyl)benzophenone, 2,4,6-trimethylbenzophenone, etc., but the benzophenone-based photoinitiator is not limited thereto. These may be used alone or in combination of two or more.

[0057] Examples of thioxanthone-based photoinitiators include 2-isopropylthioxanthone, 4-isopropylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone, 1-chloro-4-propoxythioxanthone, and 2-(3-dimethylamino-2-hydroxy)-3,4-dimethyl-9H-thioxanthone-9-one mesochloride, but the thioxanthone-based photoinitiator is not limited thereto. These may be used alone or in combination of two or more.

[0058] Examples of acylphosphine oxide photoinitiators include bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, and 2,4,6-trimethylbenzoylphenylethoxyphosphine oxide, but the acylphosphine oxide photoinitiator is not limited thereto. These may be used alone or in combination of two or more. The acylphosphine oxide photoinitiator preferably contains at least one compound selected from the group consisting of the compounds exemplified above, and more preferably contains 2,4,6-trimethylbenzoyldiphenylphosphine oxide. The acylphosphine oxide photoinitiator may be 2,4,6-trimethylbenzoyldiphenylphosphine oxide.

[0059] The component (E) may contain at least one compound selected from the group consisting of the compounds exemplified above.

[0060] The content of component (E) is not particularly limited. The content of component (E) is preferably 0.1 to 20 parts by mass, more preferably 0.5 to 10 parts by mass, and particularly preferably 1 to 5 parts by mass, per 100 parts by mass of the photocurable resin component. A content of component (E) in the range of 0.1 to 20 parts by mass per 100 parts by mass of the photocurable resin component results in a superior reaction rate in short-time curing and a lower likelihood of change in the cured product over time. When two or more compounds are used as component (A), the amount of component (A) represents the total amount of these. When two or more compounds are used as component (B), the amount of component (B) represents the total amount of these. When two or more compounds are used as component (C), the amount of component (C) represents the total amount of these. When two or more compounds are used as component (D), the amount of component (D) represents the total amount of these. When two or more compounds are used as component (E), the amount of component (E) represents the total amount of these. When two or more compounds are used as the optional (meth)acrylate monomer, the amount of the optional (meth)acrylate monomer represents the total amount thereof. When two or more compounds are used as the optional (meth)acrylate oligomer, the amount of the optional (meth)acrylate oligomer represents the total amount thereof.

[0061] <Optional Components> In addition to the above components, various monomers, oligomers, and / or additives may be added as optional components to the photocurable resin composition according to some embodiments, as long as the effects of the present invention are not impaired. The optional components may be used alone or in combination. The optional components are not particularly limited. Examples of optional components include (meth)acrylate monomers (excluding (A) and excluding component (D)), (meth)acrylate oligomers (excluding (A) and excluding component (D)), silane coupling agents, polythiol compounds, storage stabilizers, plasticizers, fillers, tackifiers, colorants, rust inhibitors, antifoaming agents, dispersants, surfactants, antioxidants, light stabilizers, UV absorbers, viscoelasticity modifiers, thickeners, etc. The colorant is not particularly limited. Examples of colorants include organic pigments, inorganic pigments, dyes, etc.

[0062] The photocurable resin composition according to some embodiments may or may not contain a (meth)acrylate monomer as an optional component. The (meth)acrylate monomer may be used alone or in combination. However, the (meth)acrylate monomer is excluding component (A) and component (D). The (meth)acrylate monomer is excluding urethane (meth)acrylates having a bisphenol skeleton, urethane (meth)acrylates having a polybutadiene skeleton, and (meth)acrylates having a fluorene skeleton. The (meth)acrylate monomer may include monofunctional, difunctional, trifunctional, or higher functional polyfunctional (meth)acrylate monomers. These may be used alone or in combination. These may be used as diluents when synthesizing component (A), but in that case, it is preferable to use a (meth)acrylate monomer without a hydroxyl group. The photocurable resin composition according to some embodiments may or may not contain a monofunctional (meth)acrylate monomer.

[0063] Specific examples of monofunctional (meth)acrylate monomers include ethyl (meth)acrylate, n-butyl (meth)acrylate, tert-butyl (meth)acrylate, isobutyl (meth)acrylate, isobornyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isodecyl (meth)acrylate, butoxydiethylene glycol (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, glycidyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, caprolactone-modified tetrahydrofurfuryl (meth)acrylate, cyclohexyl (meth)acrylate, and dicyclopentanyl (meth)acrylate. Examples of the monofunctional (meth)acrylate monomer include acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxy (meth)acrylate, isobornyl (meth)acrylate, adamantyl (meth)acrylate, benzyl (meth)acrylate, phenyl (meth)acrylate, phenoxyethyl (meth)acrylate, phenoxydiethylene glycol (meth)acrylate, phenoxytetraethylene glycol (meth)acrylate, nonylphenoxyethyl (meth)acrylate, butoxyethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, glycerol (meth)acrylate, and trifluoroethyl (meth)acrylate. However, the monofunctional (meth)acrylate monomer is not limited to these. These may be used alone, or two or more may be used in combination. The monofunctional (meth)acrylate monomer preferably contains at least one compound selected from the group consisting of the compounds exemplified above, more preferably contains isobornyl (meth)acrylate, and even more preferably contains isobornyl methacrylate. The monofunctional (meth)acrylate monomer may be isobornyl (meth)acrylate or isobornyl methacrylate.

[0064] Specific examples of bifunctional (meth)acrylate monomers include 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,3-butylene glycol di(meth)acrylate, 1,4-butylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, polytetramethylene glycol (meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, neopentyl glycol-modified trimethylolpropane di(meth)acrylate, etc., but the bifunctional (meth)acrylate monomer is not limited to these. These may be used alone or two or more types may be used in combination.

[0065] Specific examples of trifunctional or higher functional (meth)acrylate monomers include trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, EO-modified trimethylolpropane tri(meth)acrylate, PO-modified trimethylolpropane tri(meth)acrylate, alkoxylated glycerin tri(meth)acrylate, pentaerythritol tetraacrylate, ditrimethylolpropane tetraacrylate, polypentaerythritol polyacrylate, etc., but the trifunctional or higher functional (meth)acrylate monomer is not limited thereto. These may be used alone or in combination of two or more.

[0066] Examples of the (meth)acrylate monomer also include a (meth)acrylate monomer having an acidic group, such as a carboxylic acid having a (meth)acryloyl group in the molecule, or a phosphoric acid having a (meth)acryloyl group in the molecule. Examples of carboxylic acids having a (meth)acryloyl group in the molecule include (meth)acryloyl acid, 3-(meth)acryloyloxypropyl succinic acid, 4-(meth)acryloyloxybutyl succinic acid, 2-(meth)acryloyloxyethyl maleic acid, 3-(meth)acryloyloxypropyl maleic acid, 4-(meth)acryloyloxybutyl maleic acid, 2-(meth)acryloyloxyethyl hexahydrophthalic acid, 3-(meth)acryloyloxypropyl hexahydrophthalic acid, 4-(meth)acryloyloxybutyl hexahydrophthalic acid, 2-(meth)acryloyloxyethyl phthalic acid, 3-(meth)acryloyloxypropyl phthalic acid, and 4-(meth)acryloyloxybutyl phthalic acid. Examples of phosphoric acid having a (meth)acryloyl group in the molecule include 2-ethylhexyl acid phosphate, 2-hydroxyethyl methacrylate acid phosphate, dibutyl phosphate, etc. However, the (meth)acrylate monomer having an acidic group is not limited to these.

[0067] The (meth)acrylate monomer may contain at least one compound selected from the group consisting of the compounds exemplified above.

[0068] The content of the (meth)acrylate monomer is not particularly limited. The content of the (meth)acrylate monomer is preferably 0 to 50% by mass relative to the total photocurable resin components. The photocurable resin composition preferably does not contain a (meth)acrylate monomer, or contains a (meth)acrylate monomer, and the content of the (meth)acrylate monomer is preferably greater than 0% by mass and less than 50% by mass relative to the total photocurable resin components. The content of the (meth)acrylate monomer is more preferably 5 to 40% by mass, and particularly preferably 10 to 30% by mass, relative to the total photocurable resin components. By containing the (meth)acrylate monomer in the range of 0 to 50% by mass relative to the total photocurable resin components, a photocurable resin composition with superior adhesive strength of the cured product can be obtained. The content of the (meth)acrylate monomer relative to 100 parts by mass of component (A) is preferably 0 to 100 parts by mass, more preferably 10 to 75 parts by mass, and particularly preferably 30 to 60 parts by mass. The content of the (meth)acrylate monomer is preferably 0 to 100 parts by mass per 100 parts by mass of the component (A). Preferably, the photocurable resin composition does not contain a (meth)acrylate monomer; or preferably contains a (meth)acrylate monomer, and the content of the (meth)acrylate monomer is more than 0 parts by mass and not more than 100 parts by mass per 100 parts by mass of the component (A). The content of the (meth)acrylate monomer is more preferably 10 to 75 parts by mass, and particularly preferably 30 to 60 parts by mass per 100 parts by mass of the component (A). When two or more compounds are used as the component (A), the amount of the component (A) represents the total amount of these. When two or more compounds are used as the component (B), the amount of the component (B) represents the total amount of these. When two or more compounds are used as the component (C), the amount of the component (C) represents the total amount of these. When two or more compounds are used as the component (D), the amount of the component (D) represents the total amount of these. When two or more compounds are used as the optional (meth)acrylate monomer, the amount of the optional (meth)acrylate monomer represents the total amount thereof. When two or more compounds are used as the optional (meth)acrylate oligomer, the amount of the optional (meth)acrylate oligomer represents the total amount thereof.

[0069] The photocurable resin composition according to some embodiments may or may not contain a (meth)acrylate oligomer as an optional component. However, the (meth)acrylate oligomer is excluding component (A) and component (D). The (meth)acrylate oligomer is excluding urethane (meth)acrylates having a bisphenol skeleton, urethane (meth)acrylates having a polybutadiene skeleton, and (meth)acrylates having a fluorene skeleton. The (meth)acrylate oligomers may be used alone or in combination. Examples of the (meth)acrylate oligomer include polyester (meth)acrylate oligomers having an ester bond in the molecule, polyether (meth)acrylate oligomers having an ether skeleton, urethane (meth)acrylate oligomers having a urethane bond, polycarbonate (meth)acrylate oligomers having a carbonate skeleton, polybutadiene (meth)acrylate oligomers having a butadiene skeleton, epoxy (meth)acrylate oligomers having a bisphenol skeleton, and (meth)acrylic polymers having a (meth)acrylic group at the terminal.

[0070] Photocurable resin compositions according to some embodiments may or may not contain a silane coupling agent. By including a silane coupling agent, a photocurable resin composition having superior adhesive strength of the cured product can be obtained. Silane coupling agents may be used alone or in combination. Specific examples of silane coupling agents include glycidyl group-containing silane coupling agents, vinyl group-containing silane coupling agents, (meth)acrylic group-containing silane coupling agents, amino group-containing silane coupling agents, and mercapto group-containing silane coupling agents. These may be used alone or in combination of two or more. Examples of glycidyl group-containing silane coupling agents include 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and the like. Examples of vinyl group-containing silane coupling agents include vinyltris(β-methoxyethoxy)silane, vinyltriethoxysilane, vinyltrimethoxysilane, and the like. Examples of (meth)acrylic group-containing silane coupling agents include γ-(methacryloxypropyl)trimethoxysilane, etc.; examples of amino group-containing silane coupling agents include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, and N-phenyl-γ-aminopropyltrimethoxysilane, etc.; and examples of mercapto group-containing silane coupling agents include γ-(mercaptopropyl)trimethoxysilane, etc. These may be used alone or in combination of two or more. Note that (meth)acrylic group-containing silane coupling agents that have a (meth)acrylic group and an alkoxysilyl group are not included in components (A) to (D), are not included in (meth)acrylate monomers, and are not included in (meth)acrylate oligomers, and are treated as silane coupling agents.

[0071] The photocurable resin composition according to some embodiments may or may not contain a polythiol compound. A polythiol compound is a compound having two or more thiol groups in one molecule. The addition of a polythiol compound further improves photocurability. Polythiol compounds may be used alone or in combination. Specific examples of polythiol compounds include aliphatic polythiol compounds, aromatic polythiol compounds, and polythiol compounds having sulfide bonds, but the polythiol compounds are not limited thereto.

[0072] Photocurable resin compositions according to some embodiments may or may not contain a filler. Addition of a filler can adjust the adhesive strength and / or cure shrinkage of the cured product. Fillers may be used alone or in combination. Examples of inorganic fillers include, but are not limited to, alumina, silica, and amorphous silica. Examples of organic fillers include, but are not limited to, styrene fillers, rubber fillers, and core-shell acrylic fillers. Specific examples of silica products include FUSELEX E-1 manufactured by Tatsumori Co., Ltd. and AO-802 manufactured by Admafine Co., Ltd., and examples of amorphous silica include the Aerosil series manufactured by Nippon Aerosil Japan Co., Ltd., such as 200 (untreated), R972 (treated with dimethyldichlorosilane), R976 (treated with dimethyldichlorosilane), RY200 (treated with dimethylsilicone), RX200 (treated with hexamethyldisilazane), and R800 (treated with octylsilane), but the products are not limited to these.

[0073] <Characteristics> The curing shrinkage of the photocurable resin composition according to some embodiments is preferably 6.5% or less, more preferably 6.2% or less, even more preferably 6.1% or less, even more preferably 6.0% or less, even more preferably 5.9% or less, even more preferably 5.8% or less, even more preferably 5.5% or less, and particularly preferably 5.0% or less (lower limit: 0%). The curing shrinkage is measured when the integrated light dose is 3000 mJ / cm. ２ represents the cure shrinkage rate when the photocurable resin composition is cured at an integrated light dose of 3000 mJ / cm ２ The means for realizing this is not particularly limited, and it is preferable that the cure shrinkage rate of the photocurable resin composition falls within the above range when at least one of the realization means is employed. The cure shrinkage rate is determined by applying ultraviolet light (peak wavelength: 365 nm) at an integrated light dose of 3000 mJ / cm. ２ The curing shrinkage is preferably the curing shrinkage when the photocurable resin composition is cured by irradiation so that the specific gravity (S １ ) and the specific gravity of the cured product (S ２ ) and the specific gravity of the cured product (S ２ ) is the weight in air (W １ ) and the weight of the cured product in water (distilled water) (W ２ ) can be calculated using the following formula (i): ２ ) = W １ / (W １ -W ２ ) Formula (i) Curing shrinkage rate [%] = ((S ２ -S １ ) / S ２ )×100 Formula (ii) Details of the evaluation method will be described in the Examples.

[0074] The reaction rate of the photocurable resin composition according to some embodiments is preferably 75% or more and 100% or less, more preferably 80% or more and 100% or less, even more preferably 85% or more and 100% or less, even more preferably 90% or more and 100% or less, even more preferably 95% or more and 100% or less, and particularly preferably 99% or more and 100% or less. The reaction rate of the photocurable resin composition is measured by measuring the reaction rate of the photocurable resin composition before UV irradiation at 1635 cm from the baseline in an FT-IR measurement chart. －１ Absorption peak (CH ２ =CH ２ - group absorption peak) height P １ and ultraviolet light (peak wavelength: 365 nm) at an illuminance of 500 mW / cm ２ for 5 seconds, with an integrated light intensity of 2500 mJ / cm ２ The cured product obtained by curing the photocurable resin composition by irradiating the photocurable resin composition so as to have a wavelength of 1635 cm from the baseline in the FT-IR measurement chart. －１ Absorption peak height P ２ and the value calculated by the following formula is expressed: Reaction rate [%] = ((P １ -P ２ ) / P １ ) × 100 Details of the evaluation method will be described in the Examples.

[0075] <Production Method> The method for producing the photocurable resin composition according to the above embodiment is not particularly limited. The method for producing the photocurable resin composition according to the above embodiment may include mixing components (A) to (E) and, if necessary, the optional components described above. A preferred example of the method for producing the photocurable resin composition according to the above embodiment is a method including mixing components (A) to (E) with a (meth)acrylate monomer. The order of addition of the components is not particularly limited. It is preferable to add components (A) to (D) and, if necessary, the optional components described above, and then further add component (E). The order of addition of the components is not particularly limited. It is preferable to add components (A) to (D) and the (meth)acrylate monomer, and then further add component (E). This addition order can further reduce the progression of unintended curing reactions. It is preferable to mix the components in a light-shielded environment. By mixing the components in a light-shielded environment, the progression of unintended curing reactions can further be reduced.

[0076] <Cured Product> In the present invention, a cured product obtained by curing the photocurable resin composition according to the above aspect is also one embodiment (another aspect of the present invention). The cured product is preferably obtained by irradiating the photocurable resin composition according to the above aspect with active energy rays such as ultraviolet rays. More specifically, in some embodiments, the cured product is particularly preferably obtained by applying the photocurable resin composition according to the above aspect to an adherend and then irradiating the applied composition with active energy rays.

[0077] The adhesive strength of the cured product according to some embodiments is not particularly limited, but is preferably 2.5 MPa or more, more preferably 3.0 MPa or more, even more preferably 4.0 MPa or more, and particularly preferably 6.0 MPa or more. The adhesive strength of the cured product is measured when ultraviolet light (peak wavelength 365 nm) is applied at an integrated light intensity of 6000 mJ / cm. ２ The evaluation method is described in detail in the Examples.

[0078] <Coating Method> The method for applying the photocurable resin composition according to the above embodiment to an adherend is not particularly limited. Examples of the method for applying the photocurable resin composition according to the above embodiment to an adherend include dispensing (e.g., dispensing using an automatic coater), spraying, inkjet printing, screen printing, gravure printing, dipping, and spin coating.

[0079] <Curing Method> The photocurable resin composition according to the above embodiment can be cured by irradiation with active energy rays (e.g., ultraviolet light and / or visible light). The light source used in this case is not particularly limited, and any known light source can be used. Examples of the light source used in this case include a low-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a black light lamp, a sodium lamp, a halogen lamp, a xenon lamp, and an LED.

[0080] The device for curing the photocurable resin composition according to the above embodiment by irradiation with active energy rays (light irradiation) is not particularly limited, and examples of the device include an irradiation device having the above light source (a high-pressure mercury lamp using active energy rays such as ultraviolet light and / or visible light as a light source, and / or an LED using active energy rays such as ultraviolet light and / or visible light as a light source). Specific examples of devices for curing the photocurable resin composition according to the above embodiment by irradiation with active energy rays (light irradiation) include a belt conveyor type irradiator and a spot irradiator, but the device is not limited to these. The lower limit of the integrated light amount is not particularly limited, but is preferably 100 mJ / cm. ２ It is preferable that the concentration is equal to or higher than 500 mJ / cm. ２ The upper limit of the cumulative light amount is not particularly limited, but is 8000 mJ / cm ２ Preferably, it is less than 5000 mJ / cm ２ A preferred example of the range of the integrated light amount is 100 mJ / cm ２ More than 8000mJ / cm ２ Below, 500mJ / cm ２ 5000 mJ / cm ２The following can be mentioned: If more sufficient light irradiation is possible as described above, the photocurable resin composition according to the above embodiment can be cured in a shorter time.

[0081] <Applications> The application of the photocurable resin composition according to the above embodiment is not particularly limited. Examples of applications in which the photocurable resin composition according to the above embodiment is suitably used include casting resins, sealants, potting agents, adhesives, coating materials, lining materials, and inks. Among these, the photocurable resin composition according to the above embodiment is particularly preferably used for casting applications (casting resin applications), sealing agents, potting agents, adhesives, or coating materials, due to the excellent adhesive strength of the cured product, the excellent reaction rate in short curing times, and the low cure shrinkage rate during curing that can be achieved by the photocurable resin composition according to the above embodiment. For example, the photocurable resin composition according to the above embodiment is particularly preferably used for casting applications. The photocurable resin composition according to the above embodiment can be used in, for example, various electrical and electronic fields, medical applications, automotive applications, building applications, civil engineering applications, and other fields.

[0082] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. Hereinafter, the photocurable resin composition will be simply referred to as the composition. Unless otherwise specified, tests were conducted at 23°C and a relative humidity of 50% RH.

[0083] Examples 1 to 4 and Comparative Examples 1 to 8 The following components were prepared to prepare compositions.

[0084] [Component (A)] ((A-1): Urethane (meth)acrylate having a bisphenol skeleton) - Urethane methacrylate oligomer having a bisphenol A skeleton and a polytetramethylene glycol skeleton (weight average molecular weight: 14,000, number of methacrylic functional groups: 2, hereinafter referred to as Compound 1).

[0085] The bisphenol A skeleton of the compound 1 is represented by the above general formula 2, and R ４ is an alkylene group having one or more carbon atoms, and R ５was a dimethylmethylene group, m was an integer of 1 or greater, and n was an integer of 1 or greater, and had a structure in which hydrogen atoms had been removed from both ends of a polyol. Furthermore, Compound 1 contained a polytetramethylene glycol skeleton as a portion different from the bisphenol A skeleton. The polytetramethylene glycol skeleton had a structure in which hydrogen atoms had been removed from both ends of polytetramethylene glycol.

[0086] The above (a1-1) to (a1-4) were used as raw material polyisocyanates and raw material polyols for the synthesis of Compound 1. (a1-1) is represented by the above general formula 2, and R ４ is an alkylene group having one or more carbon atoms, and R ５ A polyol was used in which (a1-1) was a dimethylmethylene group, m was an integer of 1 or greater, and n was an integer of 1 or greater. Tolylene diisocyanate was used as (a1-2). A compound containing one hydroxyl group and one methacryloyloxy group in the molecule was used as (a1-3). Polytetramethylene glycol was used as (a1-4). In Compound 1, the bisphenol skeleton was a partial structure derived from (a1-1) above, and the polytetramethylene glycol skeleton was a partial structure derived from (a1-4) above.

[0087] Compound 1 can be synthesized by a method including adding (a1-2) to (a1-1) or adding (a1-2) to (a1-4); then adding the remaining component ((a1-4) or (a1-1)) and adding it stepwise; and then adding (a1-3) and adding it.

[0088] ((A-2): Urethane (meth)acrylate having a polybutadiene skeleton) Urethane acrylate oligomer having a hydrogenated polybutadiene skeleton (weight average molecular weight: 12,000, number of functional groups of acrylic groups: 2, hereinafter referred to as synthetic product 2).

[0089] In the synthesis of Compound 2, the above-mentioned (a2-1) to (a2-3) were used as the raw polyisocyanate and raw polyol. As (a2-1), a polyol in which hydroxyl groups were bonded to two ends of hydrogenated polybutadiene via alkylene groups was used. As (a2-2), a diisocyanate (diisocyanate compound) was used. As (a2-3), a compound containing one hydroxyl group and one acryloyloxy group in the molecule was used.

[0090] Compound 2 can be synthesized by a method including: reacting (a2-1) with (a2-2) to obtain a urethane prepolymer; and reacting the obtained urethane prepolymer with (a2-3).

[0091] [Component (A'): Urethane (meth)acrylate oligomer other than (A-1) and (A-2)] Urethane acrylate oligomer having a polycarbonate skeleton (UF-8001G, weight average molecular weight: 4500, number of functional acrylic groups: 2, manufactured by Kyoeisha Chemical Co., Ltd.) Urethane acrylate oligomer having a polyester skeleton (ART RESIN UN-330, weight average molecular weight: 10000, number of functional acrylic groups: 2, manufactured by Negami Chemical Industrial Co., Ltd.) Urethane acrylate oligomer having a polyether skeleton (Shikou UV-3700B, weight average molecular weight: 38000, number of functional acrylic groups: 2, manufactured by Mitsubishi Chemical Corporation).

[0092] [Component (B): (meth)acrylamide having a heterocyclic structure] 4-acryloylmorpholine (ACMO KJ Chemicals Co., Ltd.).

[0093] [Component (C): (meth)acrylamide represented by general formula 1] N,N-dimethylacrylamide (DMAA manufactured by KJ Chemicals Co., Ltd.) N,N-diethylacrylamide (DEAA manufactured by KJ Chemicals Co., Ltd.).

[0094] [Component (D): (meth)acrylate having a fluorene skeleton] - An acrylate having a cardo structure and a fluorene skeleton (a (meth)acrylate having a cardo structure in which two aromatic rings are bonded to a fluorene skeleton, OGSOL EA-0300, number of functional groups in the acrylic group: 2, manufactured by Osaka Gas Chemicals Co., Ltd.).

[0095] [Component (E): Photoinitiator] 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (DOUBLECURE TPO, manufactured by Doublebond Chemical Co.).

[0096] [Optional Components] Isobornyl methacrylate (Light Ester IB-X, monofunctional methacrylate monomer, manufactured by Kyoeisha Chemical Co., Ltd.) Tricyclodecane dimethanol diacrylate (Light Acrylate DCP-A, bifunctional acrylate monomer, manufactured by Kyoeisha Chemical Co., Ltd.) Polyethylene glycol diacrylate (Light Acrylate 9EG-A, bifunctional acrylate monomer, manufactured by Kyoeisha Chemical Co., Ltd.) Trimethylolpropane triacrylate (NK Ester A-TMPT, trifunctional acrylate monomer, manufactured by Shin-Nakamura Chemical Co., Ltd.).

[0097] In components (A), (A'), and (D), the acrylic group (i.e., acryloyl group) was present in the form of an acryloyloxy group, and the methacrylic group (i.e., methacryloyl group) was present in the form of a methacryloyloxy group.

[0098] Compositions of Examples 1 to 4 and compositions of Comparative Examples 1 to 8 were each prepared. Each composition was prepared by weighing out component (A) (or component (A')), component (B), component (C), component (D), and any optional components and charging them into a stirring vessel, followed by stirring for 60 minutes, and then weighing out component (E) and charging it into the stirring vessel, followed by stirring for 60 minutes while vacuum degassing. Each composition was prepared in a light-shielded environment. Detailed preparation amounts were as shown in Table 1.

[0099] In Table 1, the numerical values ​​for each component and the total of these components are all expressed in parts by mass. Furthermore, in Table 1, a blank space for each component indicates that the component was not used.

[0100] <Curing shrinkage rate> The specific gravity (S １ ) was measured by the specific gravity cup method (JIS K 6833-1:2008). In addition, ultraviolet light (peak wavelength: 365 nm) was irradiated by a belt conveyor-type ultraviolet irradiator using a high-pressure mercury lamp with an integrated light intensity of 3000 mJ / cm. ２ The composition was cured by irradiating the composition so that the weight in air (W １ ) and the weight in water (distilled water) (W ２ ) and W were measured. １ and W ２ The specific gravity of the cured product (S ２ ) was obtained. １ and S ２ The cure shrinkage rate [%] was calculated using the following formula. In this evaluation, the cure shrinkage rate is preferably 6.5% or less, and more preferably 6.2% or less. ２ ) = W １ / (W １ -W ２ ) Curing shrinkage rate [%] = ((S ２ -S １ ) / S ２ ) × 100 The cure shrinkage is shown in Table 1.

[0101] <Adhesion Strength Measurement> Each of the compositions of the Examples and Comparative Examples shown in Table 1 was applied to a stainless steel (SUS304) test piece measuring 25 mm wide x 100 mm long x 1.6 mm thick. A transparent polycarbonate test piece measuring 25 mm wide x 100 mm long x 2 mm thick was then bonded and fixed to the stainless steel test piece to which each composition had been applied, so that the overlapping area was 25 mm x 10 mm, thereby obtaining each laminate. Then, ultraviolet light (peak wavelength: 365 nm) was irradiated using a belt conveyor-type ultraviolet irradiator with a high-pressure mercury lamp at an integrated light intensity of 6,000 mJ / cm. ２ The laminate was irradiated from the polycarbonate test piece side so that the composition was cured to obtain a test piece.

[0102] The shear bond strength of the obtained test specimen was measured at 25°C using a universal tensile tester (tensile speed 50 mm / min) in accordance with JIS K 6850:1999. The value at the maximum shear bond strength is shown in Table 1 as adhesive strength [MPa]. In this evaluation, the adhesive strength is preferably 2.5 MPa or more.

[0103] <Reaction rate in short-time curing> The reaction rate of the composition can be determined by the reduction rate of acrylic or methacrylic groups. The reduction rate can be determined by measuring the IR spectrum using an FT-IR (Spectrum 100, manufactured by PerkinElmer).

[0104] 1635 cm from the baseline in the FT-IR measurement chart of the composition before UV irradiation －１ Absorption peak (CH ２ =CH ２ - group absorption peak) height P １ and UV-LED (peak wavelength: 365 nm, illuminance: 500 mW / cm ２ ) After 5 seconds of irradiation (accumulated light amount 2500 mJ / cm ２ ) 1635 cm from the baseline in the FT-IR measurement chart of the cured product －１ Absorption peak height P ２ The reaction rate [%] was calculated using the following formula. In this evaluation, the reaction rate is preferably 75% or more, more preferably 80% or more, and particularly preferably 85% or more, in that there is no risk of the physical properties of the cured product changing over time. Reaction rate [%] = ((P １ -P ２ ) / P １ ) × 100 The reaction rates are shown in Table 1.

[0105]

[0106] It was confirmed that the compositions of Examples 1 to 4 containing components (A) to (E) had excellent adhesive strength of the cured product, a high reaction rate in a short curing time, and a low cure shrinkage rate.

[0107] On the other hand, Comparative Examples 1 to 3 are compositions containing component (A') instead of component (A). All of the component (A') compounds are outside the scope of the component (A). Comparative Example 1 confirmed that when component (A) was replaced with a urethane acrylate oligomer having a polycarbonate skeleton, which is a compound outside the scope of the component (A), the adhesive strength and cure shrinkage of the cured product were inferior. Comparative Example 2 confirmed that when component (A) was replaced with a urethane acrylate oligomer having a polyester skeleton, which is a compound outside the scope of the component (A), the adhesive strength of the cured product was excellent, but the short-term reactivity and cure shrinkage were inferior. Comparative Example 3 is a composition in which component (A) was replaced with a urethane acrylate oligomer having a polyether skeleton. Comparative Example 3 confirmed that when component (A) was replaced with a urethane acrylate oligomer having a polyether skeleton, which is a compound outside the scope of the component (A), the adhesive strength and cure shrinkage of the cured product were excellent, but the short-term reactivity was inferior.

[0108] Comparative Example 4 is a composition that does not contain component (C). From Comparative Example 4, it was confirmed that the composition that does not contain component (C) is inferior in adhesive strength of the cured product and in reaction rate in short-time curing.

[0109] Comparative Example 5 is a composition that does not contain component (D). From Comparative Example 5, it was confirmed that the composition that does not contain component (D) was inferior in adhesive strength and cure shrinkage of the cured product.

[0110] Comparative Examples 6 to 8 are compositions in which an optional acrylate monomer was used instead of component (D). Comparative Examples 6 to 8 confirmed that compositions containing an optional acrylate monomer but not component (D) were inferior in adhesive strength of the cured product and in reactivity in short-time curing.

[0111] The photocurable resin composition according to one embodiment of the present invention can suppress the cure shrinkage rate during curing to a low level, and has excellent adhesive strength and reactivity of the cured product in a short curing time. For this reason, the composition is extremely useful in various applications, such as casting applications (casting resin applications), sealants, potting agents, adhesives, and / or coating materials, in various fields, such as electrical and electronics, medical, automotive, building, and / or civil engineering.

[0112] This application is based on Japanese Patent Application No. 2024-63070, filed on April 10, 2024, the disclosure of which is incorporated herein by reference in its entirety.

Claims

1. A photocurable resin composition comprising the following components (A) to (E): Component (A): (A-1) a urethane (meth)acrylate having a bisphenol skeleton and / or (A-2) a urethane (meth)acrylate having a polybutadiene skeleton; Component (B): a (meth)acrylamide having a heterocyclic structure; Component (C): a (meth)acrylamide represented by the following general formula 1: In the above general formula 1, R １ represents a methyl group or a hydrogen atom, R ２ and R ３ each independently represents an alkyl group having 1 to 5 carbon atoms or a hydrogen atom; component (D): a (meth)acrylate having a fluorene skeleton; component (E): a photoinitiator.

2. The photocurable resin composition according to claim 1, wherein (A-1) is a urethane (meth)acrylate having a bisphenol skeleton and a polyether skeleton.

3. The photocurable resin composition according to claim 1, wherein the component (A) is a urethane (meth)acrylate having a bisphenol skeleton and a polyether skeleton.

4. The photocurable resin composition according to claim 1 or 2, wherein the polybutadiene skeleton is a hydrogenated polybutadiene skeleton.

5. The photocurable resin composition according to any one of claims 1 to 3, wherein the bisphenol skeleton is not a hydrogenated bisphenol skeleton.

6. The photocurable resin composition according to any one of claims 1 to 3, wherein the component (B) is a (meth)acrylamide having a morpholine ring skeleton.

7. The photocurable resin composition according to any one of claims 1 to 3, wherein the component (B) is 4-acryloylmorpholine.

8. A photocurable resin composition according to any one of claims 1 to 3, wherein the total amount of component (B) and component (C) is 1 to 50 mass% based on the total amount of the photocurable resin components.

9. A photocurable resin composition according to any one of claims 1 to 3, wherein the content of component (D) is 1 to 50 mass % based on the total amount of the photocurable resin components.

10. Accumulated light intensity: 3000 mJ / cm ２ The photocurable resin composition according to any one of claims 1 to 3, which has a cure shrinkage of 6.5% or less when cured at 200°C.

11. The photocurable resin composition according to any one of claims 1 to 3, which is used for casting purposes.

12. A cured product obtained by curing the photocurable resin composition according to any one of claims 1 to 3.

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