Photocurable composition

Abstract

A photocurable composition containing at least the following component (A), component (B), component (C), and component (D): component (A): a compound having two or more glycidyl groups per molecule; component (B): a compound having a glycoluric acid structure in one molecule and having two or more thiol groups. Component (C): at least one type of photobase generator selected from the group consisting of biguanide compounds having a cyclic group and carbamates having a cyclic group; and component (D): a photosensitizer having an anthraquinone skeleton, in which the ratio of component (C) is 1-10 mass% with respect to the total mass of component (A), component (B), and component (C).

Description

Technical Field

[0001] The present application relates to a photocurable composition having excellent reactivity and storage stability and capable of forming a cured product having excellent curability. Background Art

[0002] Photocurable compositions can generally be classified into three types: radical type, cationic type, and anionic type, depending on the components generated by the initiator upon light irradiation. Among them, radical-type photocurable compositions can improve the photocuring rate of monomers, oligomers, or polymers, and thus have been widely developed and practically used. However, since the polymerization reaction of radical-type photocurable compositions is inhibited by oxygen in the air, special designs for oxygen blocking are required.

[0003] On the other hand, although cationic-type photocurable compositions do not have the inhibition of the polymerization reaction caused by oxygen as in radical-type photocurable compositions, strong acids generated by photoacid generators remain in the resin even after curing. Therefore, corrosion and resin yellowing may occur due to the presence of such strong acids.

[0004] Based on such a background, as a new photocurable composition that does not have the oxygen inhibition as in radical-type photocurable compositions, and also does not have the corrosion and yellowing caused by acids as in cationic-type photocurable compositions, and has more excellent reactivity, anionic-type photocurable compositions that generate a base by the action of light and use the base as a catalyst have attracted attention.

[0005] Along with this attention, anionic-type photocurable compositions are required not only for the high performance and miniaturization of packages for electronic components that support high-speed communication technologies, but also for long-term durability and heat resistance in high-temperature environments. In addition, in the manufacturing process of components, in order to suppress the generation of peeling and cracks caused by thermal strain at the bonding interface between resin and metal or between resin and ceramic, and reduce damage to components, a lower curing temperature of the curing process is also required.

[0006] Prior Art Documents

[0007] Patent Documents

[0008] Patent Document 1: International Publication No. 2013 / 089100

[0009] Patent Document 2: Japanese Patent Application Laid-Open No. 2009-167252 Summary of the Invention

[0010] The photocurable composition according to one aspect of the present application contains at least the following components (A), (B), (C), and (D).

[0011] Component (A): A compound having two or more glycidyl groups in one molecule;

[0012] Component (B): A compound having a glycoluril acid structure in one molecule and having two or more thiol groups;

[0013] Component (C): A photo-base generator, which is at least one selected from a biguanide compound having a cyclic group and a carbamate having a cyclic group; and

[0014] Component (D): A photosensitizer having an anthraquinone skeleton,

[0015] With respect to the total mass of the above-mentioned component (A), the above-mentioned component (B), and the above-mentioned component (C), the proportion of the above-mentioned component (C) is 1 to 10% by mass. Detailed Description

[0016] For example, when curing a conventionally used epoxy resin composition for electronic materials (a type of anionic photocurable composition) to form a sealed body, or when forming an insulating coating on the surface of an element within a component, for the purpose of improving the heat resistance of the epoxy resin, it is necessary to heat and cure the epoxy resin composition at a relatively high temperature (for example, 120 °C or higher). It is difficult for an epoxy resin composition that produces a cured product with such excellent heat resistance to achieve both excellent low-temperature curability (reactivity) and excellent storage stability.

[0017] For example, in Patent Document 1, regarding a photoanionic initiator as a photo-base initiator, curing of an epoxy resin using a compound that generates a strongly basic amidine by light, and a composition composed of an epoxy resin and a thiol compound are disclosed. However, when using the epoxy resin and thiol described in Patent Document 1, the curability and storage stability at 90 °C are excellent, but the heat resistance of the cured product is insufficient.

[0018] In addition, Patent Document 2 discloses an epoxy resin composition for a sealant, which contains: an epoxy resin (A) having an epoxy group, an organic compound (B) having a mercapto group, and a benzoxazine compound (C). By including a thiol compound as the organic compound (B), room-temperature curability is imparted to the composition. In addition, by including a benzoxazine compound (C) that increases the glass transition temperature of the cured product, heat resistance (specifically, the glass transition temperature is 140 to 150 °C) is imparted to the cured product of the composition. However, since this composition starts to cure at room temperature (for example, 25 °C), the storage stability is poor. Thus, epoxy resin compositions that produce cured products with heat resistance are insufficient in achieving both excellent low-temperature curability and excellent storage stability.

[0019] This application was completed to solve the above-mentioned conventional problems, and its object is to provide a photocurable resin composition having excellent low-temperature curability (reactivity), storage stability, and heat resistance.

[0020] Hereinafter, embodiments of the present application will be specifically described. The present application is not limited to this embodiment. The present application can be implemented with appropriate modifications within the scope of the object of the present application.

[0021] In the numerical ranges mentioned in this specification, unless special terms such as "less than", "greater than", and "less than" are added, the lower limit value and the upper limit value itself are also intended to be included. For example, taking a numerical range such as 1 to 10% by weight as an example, this numerical range is interpreted as including the lower limit value "1% by weight" and the upper limit value "10% by weight".

[0022] Hereinafter, the photocurable composition of the embodiment of the present application (hereinafter referred to as "this embodiment") will be described in detail.

[0023] <Photocurable Composition>

[0024] The photocurable composition of the embodiment of the present application (hereinafter referred to as this embodiment) contains:

[0025] Component (A): A compound having two or more glycidyl groups in one molecule;

[0026] Component (B): A compound having a glycoluril structure in one molecule and having two or more mercapto groups;

[0027] Component (C): A photo-base generator, which is at least one selected from a biguanide compound having a cyclic group and a carbamate having a cyclic group; and

[0028] Component (D): A photosensitizer having an anthraquinone skeleton.

[0029] In addition, in the photocurable composition of this embodiment, in addition to the above components (A), (B), (C), and (D), within the range that does not impair the main effects of the present application (the "low-temperature curability (reactivity)" and "excellent storage stability" of the photocurable composition, and the "excellent heat resistance" of its cured product), various additives and other components can also be blended. As additives, for example, reactive diluents can be cited.

[0030] The active energy rays are, for example, ultraviolet rays (UV), electron beams, α-rays, and β-rays, and specifically, ultraviolet rays.

[0031] The irradiation of the active energy rays is not particularly limited, and for example, it can be carried out at a temperature of 20°C or higher and 30°C or lower.

[0032] Hereinafter, each component (component (A), component (B), component (C), component (D) and other components) will be described in detail.

[0033] [About ingredient (A)]

[0034] The component (A) has two or more glycidyl groups (C 2 H 3 O)-CH 2 - a compound (hereinafter also referred to as a "glycidyl group-containing compound"). The glycidyl group-containing compound of the component (A) forms the main skeleton of a cured product formed by anionic polymerization of the photocurable composition of the present embodiment.

[0035] The glycidyl group-containing compound of the component (A) includes not only compounds called monomers but also prepolymers (e.g., compounds having a weight average molecular weight of less than 10,000) and polymers (e.g., compounds having a weight average molecular weight of 10,000 or more) obtained by polymerizing two or more monomers.

[0036] The glycidyl group-containing compound of the component (A) may have a functional group other than the glycidyl group in addition to the glycidyl group. Specific examples of such functional groups include epoxy, hydroxyl, acryloyl, methacryloyl, vinyl, acetal, ester, carbonyl, amide, and alkoxysilyl groups. The glycidyl group-containing compound may have these functional groups alone or in combination of two or more.

[0037] Specific examples of the component (A) include, but are not limited to, epi-bis type liquid epoxy resins, alcohol diglycidyl ethers, and derivatives thereof.

[0038] The epi-bis type liquid epoxy resin is a bisphenol diglycidyl ether (a compound having a bisphenol as a skeleton and having two or more glycidyl ether groups), for example, bisphenol A diglycidyl ether (a compound having a bisphenol A as a skeleton and having two glycidyl ether groups: a diglycidyl ether derived from bisphenol A and epichlorohydrin), bisphenol F diglycidyl ether (a compound having a bisphenol F as a skeleton and having two glycidyl ether groups: a diglycidyl ether derived from bisphenol F and epichlorohydrin).

[0039] Examples of the alcohol diglycidyl ether include aliphatic alcohol diglycidyl ether and aromatic alcohol diglycidyl ether.

[0040] Examples of derivatives of the table-bis type liquid epoxy resin include derivatives of bisphenol A glycidyl ether. Examples of derivatives of bisphenol A glycidyl ether include hydrogenated bisphenol A glycidyl ether (a glycidyl ether derived from hydrogenated bisphenol A and epichlorohydrin), and α,α,α’-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene diglycidyl ether (a compound having a glycidyl ether group with α,α,α’-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene as the skeleton).

[0041] Among them, from the viewpoint of well-balanced curability, adhesiveness of the cured product, and high physical strength, the glycidyl group-containing compound of the component (A) is preferably bisphenol A diglycidyl ether and α,α,α’-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene triglycidyl ether.

[0042] From the viewpoint of improving the heat resistance of the cured product of the photocurable composition, the glycidyl group-containing compound of the component (A) is preferably a glycidyl group-containing compound having 3 or more glycidyl ether groups.

[0043] In addition, from the viewpoints of improving the transparency, weather resistance, and flexibility of the photocurable composition, the glycidyl group-containing compound of the component (A) is preferably a glycidyl group-containing compound having an aliphatic hydrocarbon, a cycloaliphatic hydrocarbon (aliphatic ring), and an aromatic hydrocarbon (aromatic ring) in the skeleton (that is, a glycidyl group-containing compound having at least one ring selected from an aromatic ring and an aliphatic ring in the skeleton). Here, examples of the aromatic ring include a monocyclic aromatic ring (more specifically, a benzene ring), a polycyclic aromatic ring (a ring formed by fusion of two or more aromatic rings: more specifically, a naphthalene ring, an anthracene ring, and a phenalene ring, etc.). These rings can be further fused with an aliphatic ring. Examples of the aliphatic ring include a monocyclic aliphatic ring (more specifically, a cyclopentane ring, a cyclohexane ring, and a cycloheptane ring, etc.) and a fused ring (more specifically, a bicycloundecane ring, etc.). Examples of the glycidyl group-containing compound having an aromatic hydrocarbon in the skeleton include bisphenol type diglycidyl ether (more specifically, α,α,α’-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene triglycidyl ether and BATG manufactured by Showa Denko K.K. described later).

[0044] Commercially available epoxy resin products are not limited to these, and examples thereof include JER (formerly EPIKOTE) 828, 1001, 801, 806, 807, 152, 604, 630, 871, YX8000, YX8034, and YX4000 manufactured by Mitsubishi Chemical Corporation, Denacol EX614B, EX411, EX314, EX201, EX212, and EX252 manufactured by Nagase ChemteX Co., Ltd., TEPIC, TEPIC-S, and TEPIC-VL manufactured by Nissan Chemical Industries, Ltd., BATG manufactured by Showa Denko K.K., and VG3101L manufactured by Printec Co., Ltd. These commercially available epoxy resin products may be used alone or in combination of two or more.

[0045] The content of the component (A) is, for example, 45 to 65 parts by mass based on 100 parts by mass of the total mass of the components (A), (B), and (C) contained in the photocurable composition of the present embodiment.

[0046] [About ingredient (B)]

[0047] Component (B) is a compound having a glycoluric acid structure and two or more thiol groups in one molecule (hereinafter also referred to as a "thiol group-containing glycoluril derivative"). In this specification, "glycouric acid structure" refers to a compound having glycoluril (also known as acetylene carbamide or tetrahydroimidazo[4,5-d]imidazole-2,5(1H,3H)-dione; C 4 H 6 N 4 O 2 ) is a condensed heterocyclic structure after hydrogen atoms bonded to four nitrogen atoms of glycoluril. The thiol group-containing glycoluril derivative is a compound in which at least two of the hydrogen atoms bonded to the four nitrogen atoms of glycoluril are substituted with a functional group having a thiol group.

[0048] The thiol group-containing glycoluril derivative of the component (B) functions as a crosslinking agent in the photocurable composition of the present embodiment. Specifically, when the photocurable composition of the present embodiment is irradiated with light, the component (C) decomposes to generate a base. The generated base removes a proton (H) from the thiol group of the component (B). ＋ ), generating the thiolate anion of the component (B). The generated thiolate anion reacts with the glycidyl group of the glycidyl group-containing compound of the component (A) to form a covalent bond. It is believed that crosslinking is formed in this way.

[0049] Examples of the thiol group-containing glycoluril derivative of the component (B) include compounds represented by the following general formula (1):

[0050] [Chemical formula 1]

[0051]

[0052] In general formula (1),

[0053] R 11 、R 12 、R 13 and R 14 at least two of them contain a mercapto group,

[0054] R 11 、R 12 、R 13 and R 14 each independently represents a hydrogen atom, an alkanethiol group, or a thioether group,

[0055] R 11 、R 12 、R 13 and R 14 may be the same or different from each other].

[0056] In general formula (1), as the alkanethiol group, for example, it is an alkanethiol group having 1 to 5 carbon atoms, and can be represented by C n H 2n＋ 1 SH (n represents a positive integer from 1 to 5). As the alkanethiol group having 1 to 5 carbon atoms, for example, methyl mercaptan, ethyl mercaptan, propyl mercaptan (more specifically, n-propyl mercaptan and isopropyl mercaptan), butyl mercaptan (more specifically, n-butyl mercaptan and isobutyl mercaptan, etc.), and pentyl mercaptan (more specifically, n-pentyl mercaptan and isopentyl mercaptan, etc.) can be cited.

[0057] In general formula (1), as the thioether group, for example, it is a thioether group having 2 to 6 carbon atoms, and can be represented by C k H 2k＋1 SC m H 2m＋3 (k and m each independently represent a positive integer from 1 to 3). As the thioether group having 2 to 6 carbon atoms, for example, methylthioalkylmethyl, methylthioalkylethyl, methylthioalkylpropyl, ethylthioalkylmethyl, ethylthioalkylethyl, and ethylthioalkylpropyl can be cited.

[0058] In general formula (1), R 11 、R 12 、R 13 and R 14 each independently preferably represents C n H 2n＋1 SH (n represents a positive integer from 1 to 5), more preferably represents -C n H 2n＋1 SH (n represents a positive integer from 1 to 3), and even more preferably represents -Cn H 2n＋1 SH (where n represents a positive integer from 2 to 3).

[0059] R in general formula (1) 11 、R 12 、R 13 and R 14 The C shown n H 2n＋1 SH (where n represents a positive integer from 1 to 5) can be linear or branched, preferably linear.

[0060] In general formula (1), R 11 、R 12 、R 13 and R 14 can be the same as or different from each other, preferably the same as each other.

[0061] Preferably, a compound having a glycoluril structure as a skeleton and having 4 mercapto groups, and a compound having a thioether group in addition to 2 or more mercapto groups can be used.

[0062] As commercially available thiol products (glycoluril derivatives containing a mercapto group), for example, TS-G and C3TS-G manufactured by Shikoku Kasei Kogyo Co., Ltd. can be cited. These compounds can be used individually, respectively. In addition, 2 or more kinds can be used in combination.

[0063] With respect to 100 parts by mass in total of the components (A), (B), and (C) contained in the photocurable composition of the present embodiment, the content of the component (B) is, for example, 35 to 55 parts by mass.

[0064] [Regarding component (C)]

[0065] The component (C) is a photoacid generator, and the photoacid generator is at least 1 selected from a biguanide compound having a cyclic group and a carbamate having a cyclic group.

[0066] The photo-base generator of component (C) has a base that is latent with respect to actinic energy rays. When the photocurable composition is irradiated with actinic energy rays, the photo-base generator of component (C) decomposes to generate a base. In addition, the generated base promotes the ring-opening polymerization reaction (homopolymerization reaction) of the glycidyl groups of component (A) with each other and the addition polymerization reaction of component (B) to component (A) in the anionic polymerization reaction. Furthermore, the biguanide compound having a cyclic group and the carbamate having a cyclic group have relatively large cyclic groups, so the reactive species are not easily physically accessible to the portion corresponding to the base potentially contained in the biguanide compound and the carbamate. Therefore, the biguanide compound having a cyclic group and the carbamate having a cyclic group are not likely to undergo dark reactions. Therefore, the photocurable composition of the present embodiment has excellent storage stability because it contains component (C).

[0067] (Biguanide compound having a cyclic group)

[0068] In the present specification, a biguanide compound having a cyclic group refers to a compound or a salt thereof having a biguanide structure (a skeleton structure obtained by removing hydrogen atoms from biguanide: NC(=N)NC(=N)N) and a cyclic group. In other words, a biguanide compound having a cyclic group is a compound or a salt thereof in which at least one of the seven hydrogen atoms of biguanide (or diguanide: H 2 NC(=NH)NHC(=NH)NH 2 ) is substituted with a cyclic group.

[0069] The biguanide compound having a cyclic group is represented by the general formula (2),

[0070] [Chemical formula 2]

[0071]

[0072] [In the general formula (2),

[0073] R 21 , R 22 , R 23 , R 24 , R 25 , R 26 and R 27 each independently represent a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, and a cyclic group,

[0074] R 21 , R 22 , R 23 , R 24 , R 25 , R 26 and R 27 at least one of which represents a cyclic group].

[0075] In the general formula (2), R 21 ~R 27 Examples of the alkyl group having 1 to 3 carbon atoms include methyl group, ethyl group, n-propyl group and isopropyl group.

[0076] In the general formula (2), R 21 ~R 27 Examples of the cyclic group include an aliphatic cyclic group, an aromatic carbocyclic group, a non-aromatic heterocyclic group, and an aromatic heterocyclic group.

[0077] In the general formula (2), R 21 ~R 27 Examples of the aliphatic cyclic group include a monocyclic cycloalkyl group having 5 to 7 carbon atoms (more specifically, a cycloheptyl group, a cyclohexyl group, and a cycloheptyl group), and a polycyclic group formed by condensing these groups (condensed polycyclic group).

[0078] In the general formula (2), R 21 ~R 27 The aromatic carbocyclic group shown is an aromatic ring group in which all ring atoms are carbon atoms, and examples thereof include a monocyclic benzene ring group and a polycyclic aromatic ring group (more specifically, a bicyclic naphthalene ring group and a tricyclic anthracene ring and phenanthrene ring group).

[0079] In the general formula (2), R 21 ~R 27 The non-aromatic heterocyclic group shown in the formula (a) includes a monocyclic heterocyclic group having 5 to 6 carbon atoms (more specifically, imidazolyl, tetrahydropyranyl, piperidinyl, cyclopentylsulfide (Japanese: チアニル基) and morpholinyl (Japanese: モノフォニリニル基) etc.), a polycyclic group formed by condensing these groups, and a polycyclic group formed by condensing these groups with the above-mentioned monocyclic aliphatic ring groups.

[0080] In the general formula (2), R 21 ~R 27 The aromatic heterocyclic group shown in the formula (a) may include a monocyclic aromatic heterocyclic group, a group formed by condensing an aromatic carbocyclic group with a non-aromatic heterocyclic group (more specifically, an anthraquinone ring group, etc.), and a group formed by condensing a monocyclic aromatic heterocyclic group with an aliphatic ring group or a non-aromatic heterocyclic group. Examples of the monocyclic aromatic heterocyclic group include a furan ring group, a pyrrole ring group, a thiophene ring group, and a pyridine ring group.

[0081] In general formula (2), R 21 ~R 27 The cyclic group shown in may further have a functional group (more specifically, a hydroxyl group, a nitro group, an alkylene group, a carbonyl group, etc.). Examples of the cyclic group further having a functional group include -CR 28 (OH)C(=O)C 6 H5 (Here, R 28 represents an alkyl group having 1 to 3 carbon atoms), and nitrobenzyl (more specifically, -CH 2 -C 6 H 4 -о-NO 2 and -CH 2 -C 6 H 4 -p-NO 2 ).

[0082] In addition, the salt of the biguanide compound contains a cation and a counter anion obtained by removing one of R 21 to R 27 from the compound represented by the general formula (2). As the counter anion, for example, a borate anion can be cited.

[0083] As the borate anion, for example, tetraphenylborate and alkyltriphenylborate can be cited. The borate anion may have 4 to 20 fluorine atoms per molecule. As the tetraphenylborate, for example, tetrakis(fluorophenyl)borate (more specifically, tetrakis(3-fluorophenyl)borate, etc.) can be cited. As the alkyltriphenylborate, for example, n-butyltriphenylborate can be cited.

[0084] As the salt of the biguanide compound containing a borate anion as the counter anion, for example, 1,2-dicyclohexyl-4,4,5,5-tetramethylbiguanidinium n-butyltriphenylborate, (z)-{[bis(dimethylamino)methylene]amino}-N-cyclohexyl(cyclohexylamino)methanimonium = tetrakis(3-fluorophenyl)borate can be cited.

[0085] As the biguanide compound having a cyclic group, for example, (z)-{[bis(dimethylamino)methylene]amino}-N-cyclohexyl(cyclohexylamino)methanimonium = tetrakis(3-fluorophenyl)borate can be cited.

[0086] (Carbamate having a cyclic group)

[0087] The carbamate having a cyclic group in the present specification means a carbamate having an N-C(=O)O structure. The carbamate has at least one of a cyclic group bonded (directly or indirectly) to the nitrogen atom or oxygen atom (the rightmost oxygen atom in the chemical formula) of N-C(=O)O, and a cyclic group in which the nitrogen atom constitutes a ring-forming atom. As the cyclic group possessed by the carbamate, for example, is the cyclic group possessed by the biguanide compound.

[0088] As the carbamate having a cyclic group, for example, 9-anthrylmethyl N,N-diethylcarbamate and 1-(anthraquinon-2-yl)ethyl imidazole-1-carboxylate can be cited.

[0089] The compound represented by the general formula (2) can be synthesized by a known method. The compound represented by the general formula (2) has a cyclic group and is less likely to undergo a dark reaction between an epoxy group and a thiol group before light irradiation. Therefore, if the photocurable composition contains the compound represented by the general formula (2) as the component (C), the storage stability during pasting as the photocurable composition is excellent.

[0090] By using the above-described component (C), a strong base such as guanidine can be generated after irradiation with active energy rays (more specifically, ultraviolet rays), and the reaction with an epoxy compound or the like proceeds in a chain, and excellent reaction efficiency is achieved, so the curability is excellent.

[0091] The basicity of the urethane having a cyclic group as the component (C) is not as high as that of a photo-base generator such as a guanidine compound having a cyclic group, but its solubility in an epoxy compound or the like is excellent, and the storage stability is also excellent.

[0092] Among the above, it is more preferable that the component (C) is 1,2-dicyclohexyl-4,4,5,5-tetramethylbiguanidinium n-butyltriphenylborate or (z)-{[bis(dimethylamino)methylene]amino}-N-cyclohexyl(cyclohexylamino)methanimonium = tetrakis(3-fluorophenyl)borate which generates a strong base and has excellent reactivity. In addition, for the component (C), it is formulated in such a manner that the proportion of the component (C) is 1 to 10% by mass based on the total weight of the above component (A), the above component (B), and the above component (C). When the proportion of the component (C) is less than 1% by mass, the reactivity deteriorates and film formation cannot be achieved. On the other hand, when the proportion of the component (C) exceeds 10% by mass, the reactivity is good, but the storage stability deteriorates.

[0093] As commercially available photo-base generators, for example, WPBG-300 and 345 manufactured by Fujifilm Wako Pure Chemical Corporation can be cited. These compounds can be used alone or in combination of two or more.

[0094] With respect to 100 parts by mass of the total of the component (A), the component (B), and the component (C) contained in the photocurable composition of the present embodiment, the content of the component (C) is, for example, 1 to 10 parts by mass.

[0095] ((Component (D)))

[0096] The component (D) is a photosensitizer having an anthraquinone skeleton. The photosensitizer of the component (D) absorbs light in the ultraviolet region and sensitizes the photo-base generator of the component (C).

[0097] The photosensitizer of component (D) may have an alkyl group having 1 to 5 carbon atoms (more specifically, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, neopentyl, sec-pentyl, tert-pentyl, and 1-ethylpropyl).

[0098] Component (D) is preferably, for example, 2-methylanthraquinone, 2-ethylanthraquinone, and 2-pentylanthraquinone.

[0099] Examples of commercially available photosensitizers include 2-EAQ and 2-AAQ manufactured by Yamamoto Chemical Co., Ltd., and M0156 and B0816 manufactured by Tokyo Chemical Industry Co., Ltd. These compounds can be used alone or in combination of two or more.

[0100] With respect to 100 parts by mass in total of components (A), (B), (C), and (D) contained in the photocurable composition of the present embodiment, the content of component (D) is, for example, 0.5 to 5 parts by mass.

[0101] [Regarding other components]

[0102] (Epoxy source monomer)

[0103] The photocurable composition of the present embodiment may further contain an epoxy monomer. When the photocurable composition of the present embodiment contains an epoxy monomer, the adhesive strength of the photocurable composition can be improved when the adherend is a metal. Examples of such an epoxy monomer include phenol (EO) 5 glycidyl ether, N-glycidyl phthalimide, and 2-ethylhexyl glycidyl monomer, etc.

[0104] Examples of commercially available epoxy monomers include EX-731 (2-ethylhexyl glycidyl monomer) manufactured by Nagase ChemteX Corporation.

[0105] Examples

[0106] Hereinafter, the present application will be described more specifically by way of examples. It should be noted that the present application is not limited by any of the following examples.

[0107] Table 1 shows the conditions of components (A) to (D) in each example and comparative example, which will be described in detail later. The measurement results and determination contents are summarized.

[0108] As a production example of the photocurable resin composition 1, it will be described in Example 1.

[0109] <Example 1>

[0110] [1. Preparation of photocurable composition]

[0111] (1-1. Preparation of component (A), component (B), component (C), and component (D))

[0112] As the component (A), a glycidyl group-containing compound containing four glycidyl groups in one molecule ("Shofree (registered trademark) BATG manufactured by Showa Denko K.K., epoxy group equivalent weight 128) was prepared (represented as (A-1) in Table 1). As the component (B), a tetrafunctional thiol having a glycoluril skeleton as a parent skeleton ("C3TS-G" manufactured by Shikoku Chemical Industry Co., Ltd., thiol group equivalent weight 110) was prepared (represented as (B-1) in Table 1). As the component (C), (z)-{[bis(dimethylamino)methylene]amino}-N-cyclohexyl(cyclohexylamino)methaniminium=tetrakis(3-fluorophenyl)borate ("WPBG-345" manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was prepared (represented as (C-1) in Table 1). As the component (D), 2-pentylanthraquinone (“2-AAQ” manufactured by Yamamoto Chemicals Co., Ltd.) was prepared (referred to as (D-1) in Table 1).

[0113] (1-2. Preparation of photocurable composition)

[0114] A mixed solution of 5.19 parts by mass of component (A), 4.44 parts by mass of component (B), 0.30 parts by mass of component (C) and 0.06 parts by mass of component (D) was prepared, and the mixture was fully kneaded using a planetary mixer to prepare a photocurable composition 1 of Example 1. The composition of the photocurable composition of Example 1 is shown in Table 1. Specifically, Table 1 shows the types of components (A), (B), (C) and (D) of the photocurable composition, and the amounts of each component (unit: parts by mass).

[0115] [2. Evaluation method]

[0116] The following evaluations were performed on the various characteristics.

[0117] (2-1. Reactivity of Photocurable Composition (Low-temperature Curability))

[0118] The reactivity of a photocurable composition is evaluated based on the degree of curing of a coating film cured under specific curing conditions.

[0119] First, a photocurable composition was applied to a silicone rubber sheet to form a coating film. Next, a UV irradiator (Ushio Electric Co., Ltd. "UniJet UV-LED Series E075Z 365nm Wavelength Type") was used to illuminate the silicone rubber sheet at a cumulative light intensity of 10,000 mJ / cm 2Under the condition of [condition not specified in the original], ultraviolet-visible light near a wavelength of 365 nm was irradiated onto the coated film. Then, heat treatment was performed on the coated film under the conditions of a heating temperature of 100 °C and a heating time of 10 minutes. Thereby, a measurement sample (sample for reactivity evaluation) was prepared. In addition, except for not performing heat treatment, the same operations as for the measurement sample were carried out to prepare a blank.

[0120] Next, the cured product (coated film) was set in a differential scanning calorimeter (DSC7000X manufactured by Hitachi High-Tech Science Co., Ltd.), and the heat of reaction was measured under the measurement conditions of a measurement temperature of 20 to 350 °C and a heating rate of 20 °C / minute. In addition, the heat of reaction of the blank was also measured. Based on the heat of reaction of the photocurable composition 1 (object of measurement) obtained and the heat of reaction of its blank, the reaction rate (unit: %) was calculated using Mathematical Formula (1).

[0121] [Mathematical Formula 1]

[0122]

[0123] Based on the following evaluation criteria, the reactivity of the photocurable composition 1 was evaluated according to the calculated reaction rate. The evaluation results of the reactivity were summarized in Table 1.

[0124] (Evaluation Criteria for Reactivity)

[0125] Y (Good): The reaction rate is 80% or more

[0126] N (Poor): The reaction rate is less than 80%

[0127] (2-2. Storage Stability of Photocurable Composition)

[0128] 3 g of the photocurable composition was hermetically stored in a light-shielding container at an indoor temperature of 25 °C. Based on the time after hermetic sealing, the time (days) until the photocurable composition gelled and did not flow was measured visually. Here, the state of gelling and not flowing was evaluated as a state where it took 1 second or more for the surface of the photocurable composition to become parallel to the horizontal plane starting from tilting the container by 90°. The evaluation results of the storage stability were summarized in Table 1. In Table 1, the mark ">14 days" in "Time to Gelation (days)" indicates the result of no gelation for 14 days or more.

[0129] (Evaluation Criteria for Storage Stability)

[0130] Y (Good): The photocurable composition 1 hermetically stored in a light-shielding container did not gel for 14 days or more

[0131] N (Poor): The photocurable composition hermetically stored in a light-shielding container gelled in less than 14 days

[0132] (2-3. Heat resistance of the cured product of the photocurable composition)

[0133] The glass transition temperature of the cured product of the photocurable composition was measured to evaluate the heat resistance of the cured product.

[0134] First, a measurement sample was prepared. The heat treatment conditions were changed from a heating temperature of 100 °C and a heating time of 10 minutes to a heating temperature of 100 °C and a heating time of 10 minutes, and a heating temperature of 150 °C and a heating time of 30 minutes. Except for this, the operation was the same as in (2-2. Reactivity of the photocurable composition) to prepare a measurement sample (sample for heat resistance evaluation).

[0135] Using a dynamic viscoelasticity measuring device ("DMA7100" manufactured by Hitachi High-Tech Science Corporation), the glass transition temperature of the measurement sample (cured product of photocurable composition 1) was measured. The measurement conditions were a heating rate of 10 °C / minute and an application frequency of 10 Hz. As a result of the measurement, the temperature at the peak of the obtained loss rigidity modulus (G'') was taken as the glass transition temperature. Based on the following evaluation criteria, the heat resistance of the cured product of the photocurable composition was evaluated according to the obtained glass transition temperature. The evaluation results were summarized in Table 1.

[0136] (Evaluation criteria for heat resistance)

[0137] Y (good): The glass transition temperature of the cured product of the photocurable composition is 120 °C or higher

[0138] N (poor): The glass transition temperature of the cured product of the photocurable composition is less than 120 °C

[0139] (Comprehensive evaluation)

[0140] Based on the following evaluation criteria, a comprehensive evaluation of the photocurable composition was carried out according to the evaluation results of reactivity, storage stability, and heat resistance. The results of the comprehensive evaluation were summarized in Table 1.

[0141] (Evaluation criteria for comprehensive evaluation)

[0142] Y (good): The evaluation results of reactivity, storage stability, and heat resistance are all Y (good)

[0143] N (poor): At least one of the evaluation results of reactivity, storage stability, and heat resistance is N (poor)

[0144] <Examples 2 to 4 and Comparative Examples 1 to 4>

[0145] In addition, the following reagents were prepared.

[0146] · Component (A):

[0147] A glycidyl group-containing compound having 3 glycidyl groups in one molecule (“VG3101L” manufactured by Printec Co., Ltd., 210 equivalents, denoted as (A-2) in Table 1),

[0148] · Component (B):

[0149] A tetrafunctional thiol having a glycoluril skeleton as the main skeleton (“TS-G” manufactured by Shikoku Kasei Kogyo Co., Ltd., thiol group equivalent 96) (denoted as (B-2) in Table 1) and

[0150] A tetrafunctional thiol having a pentaerythritol skeleton as the main skeleton (Showa Denko K.K. “Karenz MT (registered trademark) PE1” (pentaerythritol tetra(3-mercaptobutyrate)) 136 equivalents) (denoted as (B-3) in Table 1), and

[0151] · Component (C):

[0152] An o-nitrobenzyl type photoacid generator represented by the following chemical formula (denoted as (C-2) in Table 1)

[0153] [Chemical formula 3]

[0154]

[0155] · Component (D):

[0156] 2-Propylthioxanthone (“I0678” manufactured by Tokyo Chemical Industry Co., Ltd.) (denoted as (D-2) in Table 1)

[0157] · Component (E): Reactive diluent

[0158] An epoxy monomer (“EX-731” manufactured by Nagase ChemteX Corporation, 216 equivalents, (N-glycidylphthalimide))

[0159] Next, in Examples 2 to 4 and Comparative Examples 1 to 4, the composition shown in Table 1 was changed, and except for this, the same operations as in Example 1 were carried out to prepare photocurable compositions respectively. In addition, the reactivity, storage stability of the photocurable compositions and the heat resistance of their cured products were evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1.

[0160]

[0161] <Examples 1 to 4>

[0162] (Examples 1 to 4)

[0163] As shown in Table 1, the photocurable compositions of Examples 1 to 4 contain component (A), component (B), component (C), and component (D). The proportion of component (C) is 1 to 10% by mass based on the total mass of components (A), (B), and (C). That is, the photocurable compositions of Examples 1 to 4 are photocurable compositions within the scope of the invention of Claim 1.

[0164] As shown in Table 1, the results of the comprehensive evaluation of Examples 1 to 4 are all Y (good).

[0165] <Comparative Examples 1 to 4>

[0166] As shown in Table 1, the photocurable compositions of Comparative Examples 1 to 4 are photocurable compositions outside the scope of the invention of Claim 1, and the results of the comprehensive evaluation are all N (poor).

[0167] (Comparative Example 1)

[0168] Specifically, in the photocurable composition of Comparative Example 1, (B-3) contained as component (B) is a compound having a pentaerythritol skeleton in one molecule instead of a glycoluril structure, and thus is a compound outside the scope of component (B).

[0169] In addition, in Comparative Example 1, the heat resistance evaluation was N (poor). It is considered that this evaluation result is because (B-3) contained as component (B) does not have a glycoluril structure in one molecule, so that the density of the crosslinking obtained by the reaction of epoxy and thiol becomes small. As a result, the glass transition temperature of the cured product cannot be sufficiently increased.

[0170] (Comparative Example 2)

[0171] The photocurable composition of Comparative Example 2 does not contain component (D). (C-2) contained as component (C) is an o-nitrobenzyl type photo-base generator, and is neither a biguanide compound having a cyclic group nor a carbamate having a cyclic group.

[0172] In addition, in Comparative Example 2, the storage stability evaluation was N (poor). It is considered that this is because although the compound of component (C) has a guanidine group, it does not have a cyclohexyl group or a tetrahydropyranyl group. Therefore, component (C) functions as a reaction accelerator at 25°C (specifically, component (C) also generates a base at 25°C), and thus the addition polymerization reaction of component (A) and component (B) (the crosslinking reaction of component (A) based on component (B)) occurs.

[0173] (Comparative Example 3)

[0174] In the photocurable composition of Comparative Example 3, the proportion of component (C) was 0.52% by mass, which was not within the range of 1 to 10% by mass relative to the total mass of components (A), (B), and (C).

[0175] In Comparative Example 3, the evaluation result of reactivity was N (poor). It is considered that this is because the proportion of component (C) is very small, so the amount of base generated is reduced. As a result, the homopolymerization reaction of the glycidyl group-containing compound of component (A) and the above-mentioned addition polymerization reaction did not proceed smoothly.

[0176] In addition, in Comparative Example 3, the evaluation result of heat resistance was N (poor). It is considered that this is because the above-mentioned addition polymerization reaction and homopolymerization reaction did not proceed smoothly, so a cured product with a high crosslinking density could not be sufficiently formed.

[0177] (Comparative Example 4)

[0178] In the photocurable composition of Comparative Example 4, the compound of component (D) was 2-propylthioxanthone, which did not have an anthracene skeleton.

[0179] In Comparative Example 4, the evaluation result of reactivity was N (poor). It is considered that this is because the compound of component (D) does not have an anthraquinone skeleton, so component (C) cannot be sufficiently sensitized by the irradiated light at a wavelength of 365 nm. As a result, the amount of base generated is reduced, and the above-mentioned homopolymerization reaction and addition polymerization reaction cannot proceed smoothly.

[0180] In addition, in Comparative Example 4, the evaluation result of heat resistance was N (poor). It is considered that this is because the above-mentioned addition polymerization reaction and homopolymerization reaction did not proceed smoothly, so a cured product with a high crosslinking density could not be sufficiently formed.

[0181] From the above, it can be seen that Examples 1 to 4 included within the scope of the present application (the invention of Claim 1) are superior in reactivity, storage stability, and heat resistance compared to Comparative Examples 1 to 4 not included within the scope of the present application. Therefore, the photocurable composition of the present application has excellent reactivity, storage stability, and heat resistance.

[0182] According to the present application, a photocurable resin composition excellent in low-temperature curability (reactivity), storage stability, and heat resistance can be provided.

[0183] Industrial Applicability

[0184] The photocurable composition of the present application is cured below 100 °C by ultraviolet irradiation. Therefore, for example, it can be used as an adhesive material for heat-resistant substrates such as resin substrates. In addition, since the cured product has low corrosivity to metals, it can be used, for example, as an adhesive and coating material for metal wirings and members having electrodes.

Claims

1. A photocurable composition comprising at least the following components (A), (B), (C) and (D): Component (A): A compound having two or more glycidyl groups in one molecule; Component (B): A compound having a glycoluril structure and two or more mercapto groups in one molecule; Component (C): A photo-base generator, which is at least one selected from biguanide compounds having a cyclic group and carbamates having a cyclic group; and Component (D): A photosensitizer having an anthraquinone skeleton, The proportion of the component (C) is 1% by mass to 10% by mass based on the total mass of the components (A), (B) and (C).

2. The photocurable composition according to claim 1, wherein the compound of the component (A) has at least one ring selected from an aromatic ring and an aliphatic ring in the skeleton.

3. The photocurable composition according to claim 1 or 2, wherein the compound of the component (B) contains a compound represented by the general formula (1), In the general formula (1), R 11 、R 12 、R 13 and R 14 at least two of which contain a mercapto group R 11 、R 12 、R 13 and R 14 each independently represents a hydrogen atom, an alkanethiol group, or a thioether group, R 11 、R 12 、R 13 and R 14 are each independently the same or different from one another.

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