Curable composition for coating and cured product thereof

Abstract

Provided are: a curable composition for coating, which contains a urethane (meth) acrylate resin, an alkyl (meth) acrylate, a photopolymerization initiator, an organic peroxide, and an amine compound; and the like.

Description

[0001] Cross-reference of related applications

[0002] This application claims priority to Japanese Patent Application No. 2023-055571, which is incorporated herein by reference. Technical Field

[0003] This invention relates to curable compositions for coating and cured products thereof. Background Technology

[0004] Conventionally, curable compositions that cure by light irradiation are known. Furthermore, curable compositions that cure even under anaerobic conditions are also known.

[0005] As described above, curable compositions that are cured by light irradiation and also cured under anaerobic conditions are known, for example, curable compositions whose anaerobic curability is improved by irradiation with active energy rays, which contain compounds having (meth)acryloyl groups, saccharin, organic peroxides and photoacid-producing agents (e.g., Patent Document 1).

[0006] The curing composition described in Patent Document 1 is used for applications such as adhesives to cure the cured product.

[0007] The curable composition described in Patent Document 1, when irradiated with active energy rays, becomes a state that promotes curing under anaerobic conditions. If it is then cured under anaerobic conditions, the time until curing is complete can be shortened. In other words, the curable composition described in Patent Document 1 exhibits good stability before irradiation with active energy rays and demonstrates good anaerobic curing properties after irradiation.

[0008] Prior art literature

[0009] Patent Literature

[0010] Patent Document 1: Japanese Patent Application Publication No. 2020-172651 Summary of the Invention

[0011] Problems to be solved by the invention

[0012] However, it is also considered to use the curable composition as described in Patent Document 1 for applications other than adhesives. The curable composition described in Patent Document 1 assumes that, when applied to coating materials, good electrical insulation is required for the cured product.

[0013] However, conventional curable compositions, as described in Patent Document 1, become cured products with good electrical insulation in the portions irradiated with active energy rays, but the curing in the unirradiated portions is insufficient, and therefore may not impart good electrical insulation. Specifically, there is a problem that good electrical insulation may not be achieved in both the irradiated portion cured by irradiation with active energy rays and the unirradiated portion.

[0014] To address this, a curable composition was proposed that further incorporates an isocyanate compound into the curable composition. This curable composition is also referred to as a moisture-curing combined photocurable composition because, as described above, the un-irradiated portion cures due to moisture. However, in the un-irradiated portion, the (meth)acryloyl-containing compound that should undergo a polymerization reaction upon irradiation with active energy rays remains in an unreacted state, resulting in a semi-cured state for the curable composition. Therefore, the cured product may not necessarily possess sufficient electrical insulation properties.

[0015] Therefore, it is desirable to have a coating curing composition that can produce a cured product with good electrical insulation in both the cured portion and the un-irradiated portion described above.

[0016] In view of the above-mentioned problems and expectations, the object of the present invention is to provide a curing composition for coating, which is a curing composition that can not only cure the irradiated part irradiated by active energy rays, but also cure the unirradiated part under anaerobic conditions, and can obtain a cured product with good electrical insulation properties for both the irradiated part and the unirradiated part.

[0017] Furthermore, the objective of this invention is to provide a cured product of the above-mentioned curable composition for coating.

[0018] Solutions for solving problems

[0019] To address the aforementioned issues, the coating curable composition of the present invention comprises urethane (meth)acrylate resin, alkyl (meth)acrylate, photopolymerization initiator, organic peroxide, and amine compound.

[0020] The cured product of the present invention is a cured product of the above-mentioned coating curing composition, which adheres to the object to be coated. Attached Figure Description

[0021] Figure 1 This is a schematic diagram illustrating examples of urethane (meth)acrylate resins and (meth)acrylate alkyl esters contained in a curable composition.

[0022] Figure 2AThis is a schematic diagram illustrating examples of locations where a curable composition is applied to the surface of an IC package and then subjected to UV-based curing and anaerobic curing reactions.

[0023] Figure 2B This is a schematic diagram illustrating examples of locations where a curable composition is applied to the surface of a chip component and then subjected to UV-based curing and anaerobic curing reactions.

[0024] Figure 2C This is a schematic diagram illustrating an example of an anaerobic curing reaction occurring at the location where the curable composition enters a through-hole on the back of a component.

[0025] Figure 2D This is a schematic diagram illustrating examples of sites undergoing UV-based curing and anaerobic curing reactions after a curable composition is applied to the surface of a BGA array.

[0026] Figure 3 This is a schematic diagram illustrating a method for evaluating insulation resistance. Detailed Implementation

[0027] The following describes one embodiment of the curable composition of the present invention. The curable composition of the present invention is primarily used for coating (covering) electronic circuits and circuit components. Then, for example, the curable composition is cured to cover the aforementioned components with a cured film.

[0028] The curable composition of this embodiment comprises urethane (meth)acrylate resin, (meth)acrylate alkyl ester, photopolymerization initiator, organic peroxide and amine compound.

[0029] The curable composition of this embodiment can be cured not only by irradiation with active energy rays, but also by anaerobic conditions. Furthermore, the cured product of the curable composition has good electrical insulation properties in both the cured portion cured by the irradiation and the unirradiated portion cured by anaerobic conditions.

[0030] Thus, for example, parts such as the back side of components on a mounting substrate that cannot be irradiated by active energy rays, or through-holes that are structurally anaerobic, can have sufficient electrical insulation.

[0031] Furthermore, even parts that are not irradiated with active energy rays and are structurally anaerobic can still provide sufficient electrical insulation by being exposed to an anaerobic environment. This transition to an anaerobic state can be achieved, for example, by using deoxidizers during packaging, replacing the surrounding environment with nitrogen, or reducing the oxygen concentration in the surrounding environment through vacuum treatment.

[0032] <Carbamate (meth)acrylate resin>

[0033] The urethane (meth)acrylate resin included in the curable composition of this embodiment is not particularly limited as long as it is a polymer compound having (meth)acryloyl groups and urethane bonds in its molecule. Commercially available products can be used as the urethane (meth)acrylate resin.

[0034] It should be noted that in this specification, the term "(meth)acrylate" includes both "acrylate" and "methacrylate". The same applies to the term "(meth)acrylic acid".

[0035] The curable composition of this embodiment contains, for example, a urethane (meth)acrylate resin with two or more functionalities, a diol compound, or a urethane reaction product of a hydroxyl-containing (meth)acrylate and an aliphatic monohydric alcohol. The isocyanate compound is preferably a trifunctional or more functional isocyanate compound.

[0036] (Isocyanate compounds)

[0037] The isocyanate compound used to obtain the above-mentioned carbamate reaction product is not particularly limited as long as it has two or more isocyanate groups (-NCO) in its molecule. From the viewpoint of being able to introduce more hydrophobic groups into the molecule of the carbamate reaction product, the above-mentioned isocyanate compound is preferably a compound having three or more isocyanate groups (-NCO) in its molecule.

[0038] Examples of the aforementioned isocyanate compounds include aromatic polyisocyanate compounds, alicyclic polyisocyanate compounds, and aliphatic polyisocyanate compounds. These isocyanate compounds may have 2, 3, or 4 isocyanate groups in their molecules. From the perspective of improving the weather resistance of the cured product, isocyanate compounds that do not contain benzene rings and unsaturated bonds are preferred.

[0039] These isocyanate compounds can be used alone or in combination of two or more.

[0040] In addition, examples of the aforementioned isocyanate compounds include isocyanurates, adducts, and biuret forms of aliphatic diisocyanates with a total carbon number of 6 to 10. These isocyanate compounds, for example, have 3 or 4 isocyanate groups in their molecules. Preferably, these isocyanate compounds do not have either a benzene ring structure (aromatic ring structure) or a saturated cycloalkyl structure (saturated structure where the ring consists only of carbon atoms).

[0041] The isocyanurate body of the above-mentioned isocyanate compound is, for example, a trimer of the above-mentioned hexamethylene diisocyanate (HMDI), having three isocyanate groups in the molecule.

[0042] An adduct of the aforementioned isocyanate compound is, for example, a reaction product of trimethylolpropane and an aliphatic diisocyanate (such as HMDI mentioned above) with a total carbon number of 6 to 10. This adduct has three isocyanate groups in its molecule.

[0043] As for the aforementioned isocyanate compound, considering its good weather resistance after curing due to the absence of benzene rings, and its good solubility in the diluent when the diluent is coexisting in the urethane esterification reaction, the adduct formed by the reaction of hexamethylene diisocyanate (HMDI) with trimethylolpropane, or the isocyanurate form (trimer) of hexamethylene diisocyanate (HMDI) is preferred.

[0044] Preferably, the isocyanate compound with three or more functions is an isocyanurate ester of an aliphatic diisocyanate with a total carbon number of 6 to 10 (three-functional), and more preferably an isocyanurate ester of an aliphatic diisocyanate with a total carbon number of 8 (three-functional).

[0045] (diol)

[0046] The diol compound used to obtain the above-mentioned carbamate reaction product can be a branched polyolefin diol, an aliphatic polycarbonate diol, or an aliphatic polyether diol.

[0047] In branched polyolefin diols, the polyolefin portion, for example, the side chains of the branched structure can have unsaturated double bonds. Because the side chains of the branched structure have unsaturated double bonds, the cured product of the above-mentioned curable composition can exhibit better insulation properties. It should be noted that if the side chains of the branched structure are saturated hydrocarbons, the cured product of the above-mentioned curable composition can exhibit better heat resistance.

[0048] The aliphatic portion (the hydrocarbon portion with continuously bonded carbon atoms) in aliphatic polycarbonate diols can have 4 or more but less than 12 carbon atoms.

[0049] Examples of branched polyolefin diols include 1,2-polybutadiene diol or hydrogenated 1,2-polybutadiene diol.

[0050] Aliphatic polycarbonate diols include, for example, aliphatic polycarbonate diols in which the hydrocarbon portion, with continuous carbon atom bonding, is a straight-chain hydrocarbon.

[0051] Examples of aliphatic polyether diols include polyethylene glycol, polypropylene glycol, and polybutanediol.

[0052] Commercially available products can be used as diol compounds for obtaining the above-mentioned carbamate reaction products.

[0053] (Hydroxy-containing (meth)acrylates)

[0054] The hydroxyl-containing (meth)acrylate used to obtain the above-mentioned carbamate reaction product has one hydroxyl group and one (meth)acryloyl group in its molecule. Specifically, the hydroxyl-containing (meth)acrylate is an alkyl ester compound of (meth)acrylic acid, wherein one hydroxyl group is bonded to any carbon atom of the alkyl moiety. The number of carbon atoms in the alkyl moiety is preferably one or more and four or less. The (meth)acryloyl group of the hydroxyl-containing (meth)acrylate can initiate a polymerization reaction when irradiated with active energy rays. Furthermore, the (meth)acryloyl group of the hydroxyl-containing (meth)acrylate can initiate a polymerization reaction when placed in an anaerobic environment in the presence of organic peroxides and amine compounds.

[0055] Examples of hydroxyl-containing (meth)acrylates include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate. From the perspective of better polymerizability based on irradiation with active energy rays, 2-hydroxyethyl (meth)acrylate is preferred.

[0056] <Aliphatic monohydric alcohols>

[0057] The aliphatic monohydric alcohols that can be used to obtain the products of the above carbamate reaction are monohydric alcohols with a total number of carbons of 6 or more and 18 or less in their molecules. In other words, aliphatic monohydric alcohols are compounds with 6 or more and 18 or less carbons in their molecules and one hydroxyl group.

[0058] The hydrocarbon in an aliphatic monohydric alcohol molecule is preferably a saturated hydrocarbon. Furthermore, the hydrocarbon is preferably linear. The hydroxyl group of the aliphatic monohydric alcohol is preferably bonded to the end of the linear hydrocarbon chain.

[0059] For example, examples of aliphatic monohydric alcohols include 1-hexanol, 1-heptanol, 1-octanol, 1-nonanol, 1-decanol, 1-undecanol, or 1-dodecylol.

[0060] · Carbamate reaction products

[0061] The curable composition of this embodiment contains various of the above-described carbamate reaction products. In other words, the molecular structure of the above-described carbamate reaction products is not necessarily limited to one.

[0062] Therefore, specifying the molecular structure of all compounds contained in the curable composition of this embodiment is practically impractical. In other words, directly specifying the structure or properties of all compounds contained in the curable composition of this embodiment is practically impractical. However, specifying the molecular structure of the compounds before the urethane esterification reaction allows for a thorough prediction of the products of the urethane esterification reaction, and thus allows for a thorough prediction of the molecular structure of the urethane esterification reaction products.

[0063] Examples of the products of the above carbamate reaction include, for example, those from... Figure 1 The general formula is represented by the above-mentioned carbamate reaction products, which typically have oligomer-level molecular weights.

[0064] Alkyl (meth)acrylates

[0065] The alkyl methacrylate contained in the curable composition of this embodiment is an alkyl ester compound of (meth)acrylic acid. Examples of such alkyl methacrylates include monofunctional alkyl methacrylates having one (meth)acryloyl group in the molecule. Alkyl methacrylates are compounds capable of polymerization when irradiated with active energy rays. Furthermore, alkyl methacrylates are compounds capable of polymerization under anaerobic conditions in the presence of organic peroxides and amine compounds.

[0066] Examples of monofunctional (meth)acrylate alkyl esters include (meth)acrylate alkyl esters having a cyclic hydrocarbon structure in the molecule or (meth)acrylate alkyl esters having a chain hydrocarbon structure in the molecule.

[0067] In alkyl (meth)acrylates having a cyclic hydrocarbon structure in the molecule, the cyclic hydrocarbon structure is preferably a saturated hydrocarbon. Furthermore, the alkyl (meth)acrylate preferably has 8 to 15 carbon atoms in the molecule. Additionally, the alkyl (meth)acrylate preferably does not contain a benzene ring or any of the following polar groups: ether (-CH2-O-CH2-), -OH, and -COOH. In the alkyl (meth)acrylate, the cyclic hydrocarbon structure can be a saturated hydrocarbon structure consisting of 4 to 8 carbon atoms without heteroatoms. The alkyl (meth)acrylate can be monocyclic, bicyclic, or polycyclic. Bicyclic or polycyclic cyclic hydrocarbon structures can have two or more carbon atoms. It should be noted that in bicyclic or polycyclic alkyl (meth)acrylates, at least one cyclic hydrocarbon structure can be a saturated hydrocarbon structure, or, for example, all cyclic hydrocarbon structures can be saturated hydrocarbon structures. In the alkyl (meth)acrylate, methyl or ethyl groups can be further bonded to the carbon atoms of the saturated cyclic hydrocarbon structure.

[0068] Specifically, examples of alkyl methacrylates with cyclic hydrocarbon structures in their molecules include isobornyl methacrylate, dicyclopentadienoxyethyl methacrylate, dicyclopentyl methacrylate, dicyclopentadienoxyethyl methacrylate, and adamantyl methacrylate.

[0069] By including alkyl (meth)acrylates with cyclic hydrocarbon structures in the molecule in the above curable composition, the cured product of the curable composition can have more adequate moisture resistance and, in addition, more adequate electrical insulation.

[0070] On the other hand, in alkyl (meth)acrylates with a chain hydrocarbon structure in the molecule, the chain hydrocarbon structure can be a straight-chain hydrocarbon structure or a branched-chain hydrocarbon structure. The number of carbon atoms in the chain hydrocarbon structure can be 6 or more and 18 or less. The chain hydrocarbon structure is preferably a saturated chain hydrocarbon structure.

[0071] The alkyl (meth)acrylates with a chain hydrocarbon structure in the above-mentioned molecules are preferably free from any type of polar groups such as benzene rings, ether bonds (-CH2-O-CH2-), -OH groups, and -COOH groups. In alkyl (meth)acrylates, the chain hydrocarbon structure is preferably a saturated chain hydrocarbon structure consisting of 6 to 18 carbon atoms, free from atoms other than C and H.

[0072] By including alkyl (meth)acrylates with a chain hydrocarbon structure in the molecule in the above curable composition, the cured product of the curable composition can have more adequate moisture resistance and more adequate flexibility.

[0073] In alkyl (meth)acrylates with a chain hydrocarbon structure in the molecule, the chain hydrocarbon structure can be straight-chain or branched. In other words, the chain hydrocarbon structure can be straight-chain or branched.

[0074] As an alkyl methacrylate with a chain hydrocarbon structure in its molecule, an alkyl methacrylate with a saturated branched hydrocarbon structure is preferred from the perspective of further improving the flexibility of the cured product after curing the curable composition. Therefore, a more uniform cured product coating can be obtained with almost no influence from the substrate supporting the cured product, the thickness of the cured product, or the curing reaction conditions.

[0075] Specifically, examples of alkyl methacrylates with a saturated straight-chain hydrocarbon structure in the molecule include n-hexyl methacrylate, n-heptyl methacrylate, n-octyl methacrylate, n-nonyl methacrylate, n-decyl methacrylate, tridecyl methacrylate, lauryl methacrylate, and myristyl methacrylate.

[0076] For alkyl methacrylates with saturated branched hydrocarbon structures in their molecules, the hydrocarbon structure can be any saturated branched alkyl structure, including iso, sec, neo, or tert structures.

[0077] Specifically, examples of alkyl methacrylates with saturated branched hydrocarbon structures in their molecules include isoheptyl methacrylate, isooctyl methacrylate, isononyl methacrylate, isodecanyl methacrylate, and 2-ethylhexyl methacrylate.

[0078] The above-mentioned monofunctional (meth)acrylate alkyl esters can be used alone or in combination of two or more.

[0079] The curable composition of this embodiment preferably comprises both a (meth)acrylate alkyl ester having a cyclic hydrocarbon structure in the above-described molecule (hereinafter, sometimes referred to as (meth)acrylate cyclic alkyl ester) and a (meth)acrylate alkyl ester having a chain hydrocarbon structure having 6 or more carbon atoms in the above-described molecule (hereinafter, sometimes referred to as (meth)acrylate chain alkyl ester) as a monofunctional (meth)acrylate alkyl ester.

[0080] In the curable composition of this embodiment, the mass ratio (η / θ) of cyclic alkyl methacrylate (η) to alkyl chain methacrylate (θ) can be within a specified range. By further increasing the above-mentioned mass ratio (η / θ), the electrical insulation of the cured product can be further improved. On the other hand, by further decreasing the above-mentioned mass ratio (η / θ), the flexibility of the cured product can be further improved.

[0081] Photopolymerization initiators

[0082] The photopolymerization initiator included in the curable composition of this embodiment is not particularly limited as long as it is a compound that generates free radicals by irradiation with active energy rays (such as ultraviolet light). Examples of photopolymerization initiators include acetophenone-based polymerization initiators, acylphosphine oxide-based polymerization initiators, O-acyl oxime-based polymerization initiators, benzophenone-based polymerization initiators, thioxanone-based polymerization initiators, and acylphosphine oxide-based polymerization initiators. Among these, hydrogen-abstraction type photopolymerization initiators, such as acyl photopolymerization initiators containing camphorquinone, or benzophenone-based polymerization initiators or thioxanone-based polymerization initiators, are preferred.

[0083] Commercially available products can be used as photopolymerization initiators.

[0084] <Organic peroxides>

[0085] The organic peroxide contained in the curable composition of this embodiment is not particularly limited, and general organic peroxides can be used. Organic peroxides are compounds capable of generating free radicals, and therefore have the effect of promoting the reaction when the above-mentioned curable composition is cured under anaerobic conditions. That is, organic peroxides are compounds capable of promoting the polymerization reactions of the hydroxyl-containing (meth)acrylate residues and the alkyl (meth)acrylates in the above-mentioned urethane (meth)acrylate resin.

[0086] As an organic peroxide, an organic peroxide with a 10-hour half-life temperature of 100°C or higher is preferred. This provides the advantage of further improved storage stability of the curable composition.

[0087] Examples of organic peroxides include p-menthane hydroperoxide, diisopropylbenzene hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, isopropylbenzene hydroperoxide, or tert-butyl hydroperoxide.

[0088] <Amine compounds>

[0089] The amine compound contained in the curable composition of this embodiment is not particularly limited, and general amine compounds can be used. The amine compound promotes the reaction of the curable composition under anaerobic conditions. Furthermore, the amine compound, particularly with a specific photopolymerization initiator (the aforementioned hydrogen-abstraction type), promotes the curing reaction of the curable composition based on irradiation with active energy rays.

[0090] Examples of the aforementioned amine compounds include, for example, secondary or tertiary amines having a defined molecular structure. Additionally, examples of the aforementioned amine compounds include amine compounds having an aromatic ring structure or amine compounds having a heterocyclic structure. Preferably, the aforementioned amine compounds include at least one of a tertiary amine compound having an aromatic ring and a secondary amine compound having a heterocyclic structure.

[0091] The aforementioned amine compounds more preferably include dimethylaminobenzoate or 1,2,3,4-tetrahydroquinoline. By including these specified amine compounds in the above-described curable composition, the rate of the curing reaction of the curable composition can be moderately maintained, thus allowing the curable composition to reach the interior of the microstructure before it becomes excessively thickened as the curing reaction proceeds. Therefore, even within the microstructure, a cured product with good electrical insulation properties can be generated. Furthermore, the storage stability of the curable composition can be improved.

[0092] In the curable composition of this embodiment, the mass ratio of alkyl (meth)acrylate to the above-described urethane (meth)acrylate resin is preferably 1.0 or more and 5.0 or less. This allows the curable composition to penetrate the interior of the fine structure as described above, and the cured product exhibits good flexibility.

[0093] In the curable composition of this embodiment, the mass ratio of the organic peroxide to the total amount of the above-mentioned urethane (meth)acrylate resin and (meth)acrylate alkyl ester is preferably 0.005 or more and 0.030 or less. By setting the mass ratio to 0.005 or more, the above-mentioned curable composition can be cured more thoroughly. On the other hand, by setting the mass ratio to 0.030 or less, the electrical insulation of the cured product can be ensured more reliably.

[0094] In the curable composition of this embodiment, the mass ratio of the amine compound to the total amount of the above-mentioned urethane (meth)acrylate resin and (meth)acrylate alkyl ester is preferably 0.005 or more and 0.030 or less. By setting the mass ratio to 0.005 or more, the curable composition can be cured more thoroughly, and the electrical insulation of the cured product can be further improved. On the other hand, by setting the mass ratio to 0.030 or less, the electrical insulation of the cured product can be more reliably ensured.

[0095] <Catalyst for carbamate reaction>

[0096] To obtain the above-mentioned carbamate reaction product, a carbamate reaction catalyst can be used; therefore, the curable composition of this embodiment may contain a carbamate reaction catalyst.

[0097] As catalysts for carbamate reactions, metal-based catalysts such as organotin catalysts like dibutyltin dilaurate or stannous octoate, and acetylacetone complex catalysts can be used.

[0098] The curable composition of this embodiment may, as needed, include photosensitizers, reducing agents that facilitate curing reactions under anaerobic conditions, polymerization inhibitors, antioxidants, dyes (fluorescent dyes), pigments, etc.

[0099] Examples of reducing agents include saccharin, metal soaps for coatings such as manganese octoate or cobalt octoate that act as auxiliary agents, or organic compounds with α-hydrogen and unsaturated double bonds (such as unsaturated fatty acids, oligomers of butadiene rubber, etc.).

[0100] In the curable composition of this embodiment, the content of saccharin is preferably less than 1% by mass (including 0%), and more preferably, the curable composition is free of saccharin. By keeping the saccharin content as low as possible, the electrical insulation of the cured product can be further improved. In addition, since saccharin is one of the sulfonamides, it is preferable to have an even lower saccharin content in the cured product from the following aspects: Specifically, by keeping the saccharin content low, for example, it is possible to suppress the generation of strongly acidic compounds due to the hydrolysis of saccharin under high temperature and high humidity. In addition, it is possible to suppress the generation of corrosive sulfur compounds such as hydrogen sulfide and sulfurous acid gas due to the thermal decomposition of saccharin under high temperature conditions.

[0101] Next, one embodiment of the method for manufacturing the curable composition of the present invention will be described.

[0102] The method for manufacturing the curable composition of this embodiment includes a step of mixing urethane (meth)acrylate resin, alkyl (meth)acrylate, photopolymerization initiator, organic peroxide and amine compound.

[0103] The method for manufacturing the curable composition of this embodiment may include, for example, a step of synthesizing the above-mentioned urethane (meth)acrylate resin. It should be noted that commercially available products can be used as the above-mentioned urethane (meth)acrylate resin.

[0104] For example, the method for manufacturing the curable composition of this embodiment includes a synthesis step for synthesizing the above-mentioned urethane (meth)acrylate resin, and

[0105] The mixing process involves at least the mixing of the synthesized urethane (meth)acrylate resin, alkyl (meth)acrylate, photopolymerization initiator, organic peroxide, and amine compound.

[0106] In the above-described synthesis process, at least a diol compound is subjected to a carbamate reaction with a trifunctional or more isocyanate compound and a hydroxyl-containing (meth)acrylate to obtain the carbamate reaction product. Furthermore, the carbamate reaction can also be carried out in the presence of an aliphatic monohydric alcohol. The compounds used in the carbamate reaction are as described above.

[0107] In the synthesis process, in order to prevent undesirable reactions caused by moisture, the carbamate reaction is usually carried out after the air in the reaction vessel is replaced with nitrogen.

[0108] In the synthesis process, typical reaction conditions suitable for the carbamate reaction can be used. Preferably, the carbamate reaction is carried out in the synthesis process by maintaining a temperature of 50-90°C for 0.5-3 hours.

[0109] In the synthesis process, the preferred amounts (input amounts) of the isocyanate compound (a1) with three or more functions, the diol compound (a2), the hydroxyl-containing (meth)acrylate (a3), and the aliphatic monohydric alcohol (a4) used as needed are as follows.

[0110] In the synthesis process, the carbamate reaction is preferably carried out in such a manner that the total amount of each hydroxyl group (-OH) of the diol compound (a2), the hydroxyl-containing (meth)acrylate (a3), and the aliphatic monohydric alcohol (a4) used as needed is 0.95 moles or more and 1.00 moles or less, relative to 1 mole of the isocyanate group of the isocyanate compound (a1) with more than 3 functions.

[0111] By performing the urethane esterification reaction at the above molar ratio, even if a very small portion of the isocyanate groups decompose due to trace amounts of moisture, all hydroxyl groups can be quantitatively reacted, and the remaining isocyanate groups can be essentially eliminated. Therefore, both good electrical insulation of the cured product and good storage stability of the cured composition can be achieved.

[0112] In the synthesis process, the molar ratio of hydroxyl groups in the aliphatic monohydric alcohol (a4) to 1 mole of isocyanate compound (a1) with the number of isocyanate groups set to n in the molecule of the isocyanate compound (a1) with three or more functions is preferably (n-2)×0.8 or more and (n-2)×1.2 or less. This reduces the branched structure in the urethane (meth)acrylate resin molecule, thus providing the advantage of further improving the flexibility of the cured product.

[0113] It should be noted that when the isocyanate compound with three or more functions (a1) contains multiple isocyanate compounds, or when the aliphatic monohydric alcohol (a4) contains multiple aliphatic monohydric alcohols, the molar ratio as described above is calculated by the arithmetic mean.

[0114] In the synthesis process, relative to 1 mole of the hydroxyl group (-OH) of the diol compound (a2), the hydroxyl group (-OH) of the hydroxyl-containing (meth)acrylate (a3) ​​is preferably 0.5 moles or more and 2.0 moles or less. This provides the advantage of balancing good electrical insulation and good flexibility in the cured product.

[0115] In the synthesis process, the hydroxyl groups (-OH) of the aliphatic monohydric alcohol (a4) are preferably 0.8 moles or more and 1.2 moles or less, relative to 1 mole of the hydroxyl groups (-OH) of the diol compound (a2). This provides the advantage of improving the flexibility of the cured product.

[0116] In the synthesis process, it is preferable that the molar number of the trifunctional isocyanate compound (a1) is greater than the molar number of the diol compound (a2), and preferably the ratio of the difference between the molar number of hydroxyl groups in the hydroxyl-containing (meth)acrylate (a3) ​​and the molar number of the diol compound (a2) is 2.0 or more and 4.0 or less. This provides the advantage of achieving both good flexibility and good electrical insulation of the cured product.

[0117] The synthesis process can be carried out in one stage in the presence of isocyanate compounds with more than three functions (a1), diol compounds (a2), and hydroxyl-containing (meth)acrylates (a3), etc., to carry out the carbamate reaction.

[0118] The synthesis process is preferably carried out in two stages: a carbamate reaction is performed in the presence of a trifunctional or higher isocyanate compound (a1) and a diol compound (a2), followed by a carbamate reaction of a hydroxyl-containing (meth)acrylate (a3). This allows for more reliable production of the main chain structure formed by the reaction of a trifunctional or higher isocyanate compound with a diol compound.

[0119] In the above-mentioned mixing process, after the urethane esterification reaction, for example, the above-mentioned alkyl (meth)acrylate, photopolymerization initiator, organic peroxide and amine compound are further added.

[0120] During the mixing process, photosensitizers, polymerization inhibitors, antioxidants, fluorescent dyes, and other dyes and pigments can be added as needed.

[0121] The curable composition of this embodiment can be cured by irradiation with active energy rays such as ultraviolet light, and used as a cured product. Alternatively, the curable composition of this embodiment can be cured by exposure to an anaerobic environment, and used as a cured product.

[0122] Specifically, after applying the aforementioned curable composition to the area to be coated, the composition can be cured by irradiating it with ultraviolet light or other light to form a cured coating film. Furthermore, in areas placed in a sealed environment without light irradiation, an anaerobic curing reaction can also be carried out. Alternatively, even without placing the curable composition in a sealed environment, the curing reaction of the curable composition can be carried out by eliminating the influence of oxygen using deoxidizers, nitrogen replacement treatment, vacuum treatment, or other methods.

[0123] It should be noted that the curable composition of this embodiment can be cured by both light-based curing reaction and anaerobic curing reaction, or by either of these two curing reactions.

[0124] The active energy rays used for irradiation to carry out the curing reaction can be, for example, ultraviolet or infrared light, radiation, electron beams, etc.

[0125] Ultraviolet light is preferred as the illumination source. High-pressure mercury lamps, metal halide lamps, xenon lamps, chemical lamps, LED lamps, etc., can be used as the light source. For example, an illumination intensity of 100 W / cm² can be used. 2 Above and 10,000 mW / cm 2 the following.

[0126] The preferred temperature for the anaerobic curing reaction is 20-40°C, and the preferred oxygen concentration is less than 5 mg / L. Specific locations that constitute the anaerobic state include, for example, the gap between the IC package or mounting component and the printed circuit board, the through-hole portion of the printed circuit board, the internal electrode portion of the chip component, the area covered by cured material that has been cured by light irradiation but has not been sufficiently irradiated by light, or the back side of the lead portion of the IC package, etc.

[0127] A portion of the object to which the curable composition is coated and applied contains a metal. More specifically, at least a portion of the surface of the object coated with the curable composition may be formed of a metal. This further promotes the curing of the curable composition. The metal is not particularly limited; examples include copper, silver, iron, titanium, nickel, manganese, cobalt, tin, or lead. The metal may include a variety of metals as described above.

[0128] If metal is present on the surface to be coated, the curing of the above-mentioned curing composition proceeds more rapidly when it becomes anaerobic. It should be noted that curing reactions also occur in areas far from the metal, eventually forming a cured product. Since the resulting cured product is not liquid, it will not leak accidentally under any pressure.

[0129] The object to which the above-mentioned curable composition is applied and coated (the coated object) is mainly a component of a circuit or electronic circuit. Examples of coated objects (the above-mentioned components) include, for example, a substrate and a mounting component, a connection between the mounting component and the substrate, and a connection between the substrates.

[0130] Examples of objects to be covered include wiring and terminals on mounting base plates or mounting components used in precision equipment; wiring and terminals on mounting base plates mounted in automobiles, bicycles, railways, airplanes, ships, etc.; wiring and terminals on mounting base plates used in mobile devices (mobile phones, digital cameras, digital camcorders, etc.); wiring and terminals on base plates used in outdoor equipment (water heaters, air conditioner outdoor units, etc.); and wiring and terminals on mounting base plates used in water treatment equipment such as washing machines, warm water toilet seats, and dishwashing dryers.

[0131] For example, Figure 2AAs shown, when the above-described curable composition is coated on a portion of the surface of an IC package, the curing reaction of the curable composition occurs in the portion irradiated with active energy rays (such as ultraviolet light) (denoted by U). In the portion that can become anaerobic even when not reached by active energy rays, particularly in the area close to the metal (denoted by m1) (denoted by K), the curing reaction of the above-described curable composition occurs under anaerobic conditions. It should be noted that curing also occurs in the portion far from the metal where active energy rays do not reach (denoted by G).

[0132] In addition, for example, Figure 2B As shown, when a portion of the surface of a chip component having ceramic (s), a protective film (h), an internal electrode (m2), an external electrode (m3), and solder (m4) is coated with the above-described curable composition, a curing reaction of the curable composition occurs in the portion irradiated with active energy rays (such as ultraviolet light) (denoted by U). In portions that can become anaerobic even when not reached by active energy rays, particularly in areas close to the metal (denoted by K), the curing reaction of the curable composition occurs under anaerobic conditions. Furthermore, curing also occurs and is achieved in portions far from the metal where active energy rays do not reach (denoted by G).

[0133] In addition, for example, Figure 2C As shown, in areas such as through-holes on the back of components, where an anaerobic environment may occur, particularly in areas close to the metal (represented by m4) (represented by K), the curing reaction of the above-mentioned curable composition is carried out under anaerobic conditions. It should be noted that curing reactions also occur and curing occurs in areas far from the metal (represented by G).

[0134] In addition, for example, Figure 2D As shown, when the above-described curable composition is coated on a portion of the surface of a BGA array, the curing reaction of the above-described curable composition occurs in the portion irradiated with active energy rays (such as ultraviolet light) (denoted by U), triggered by the irradiation. Curing occurs in the portion that can become anaerobic even when the active energy rays do not reach it (denoted by G), where a curing reaction takes place and the mixture is cured.

[0135] The curable composition, cured product, and method for manufacturing the curable composition in this embodiment are illustrated above, but the present invention is not limited to the curable compositions illustrated above.

[0136] That is, various forms used in general curable compositions or the like can be employed without compromising the effects of the present invention.

[0137] The matters disclosed in this specification include the following. (1)

[0139] A coating curable composition comprising a urethane (meth)acrylate resin, an alkyl (meth)acrylate, a photopolymerization initiator, an organic peroxide, and an amine compound. (2)

[0141] According to the coating curable composition described in (1) above, the aforementioned urethane (meth)acrylate resin is a product of the urethane reaction of at least a diol compound, a trifunctional or more isocyanate compound and a hydroxyl-containing (meth)acrylate. (3)

[0143] According to the coating curable composition described in (2) above, the aforementioned diol compound comprises at least one of branched polyolefin diol and aliphatic polycarbonate diol. (4)

[0145] The coating curable composition according to any one of (1) to (3) above, wherein the aforementioned urethane (meth)acrylate resin is at least the urethane reaction product of the aforementioned isocyanate compound, the aforementioned diol compound, the aforementioned hydroxyl-containing (meth)acrylate and an aliphatic monohydric alcohol. (5)

[0147] The coating curable composition according to any one of (1) to (4) above, wherein the aforementioned alkyl methacrylate contains at least one of an alkyl methacrylate having a cyclic hydrocarbon structure in the molecule and an alkyl methacrylate having a chain hydrocarbon structure having 6 or more carbon atoms in the molecule. (6)

[0149] The coating curable composition according to any one of (1) to (5) above, wherein the aforementioned amine compound comprises at least one of dimethylaminobenzoate and 1,2,3,4,-tetrahydroquinoline. (7)

[0151] A cured product, which is a cured product of any one of the coating curing compositions described in (1) to (6) above, is adhered to the object to be coated. (8)

[0153] According to the solidified material described in (7) above, its energy storage modulus at 25°C is less than 100 MPa. (9)

[0155] A method for manufacturing a curable composition for coating includes a step of mixing a urethane (meth)acrylate resin, an alkyl (meth)acrylate, a photopolymerization initiator, an organic peroxide, and an amine compound. (10)

[0157] According to the manufacturing method described above (9), it further includes a step of synthesizing the aforementioned urethane (meth) acrylate resin by reacting a trifunctional or higher isocyanate compound with at least a diol compound and a hydroxyl-containing (meth) acrylate with a urethane ester. (11)

[0159] According to the manufacturing method described in (10) above, the aforementioned diol compound comprises at least one of branched polyolefin diol and aliphatic polycarbonate diol. (12)

[0161] According to any one of the manufacturing methods (9) to (11) above, in the step of synthesizing the aforementioned urethane (meth)acrylate resin, the urethane esterification reaction is carried out in the presence of at least the aforementioned isocyanate compound, the aforementioned diol compound, the aforementioned hydroxyl-containing (meth)acrylate and aliphatic monohydric alcohol.

[0162] Example

[0163] The invention will now be described in more detail through examples, but the invention is not limited thereto.

[0164] The following steps are performed to synthesize (A) urethane (meth)acrylate resin, and further mix (B) (meth)acrylate alkyl ester, (C) photopolymerization initiator, (D) organic peroxide, (E) amine compound, etc., to manufacture a curable composition.

[0165] Raw materials in the synthesis process

[0166] (a1) Isocyanate compounds with more than three functions

[0167] • Isocyanurate derivatives of hexamethylene diisocyanate (HMDI)

[0168] Product name "DURANATE TPA-100: Isocyanate group content 23%" manufactured by Asahi Kasei Corporation

[0169] (a2) Diol compounds

[0170] Aliphatic polycarbonate diol

[0171] (Product name "ETERNACOLL PH-50", manufactured by UBE Company) Hydroxyl value: 224 [KOH mg / g]

[0172] Branched polyolefin diols (polybutadiene diol)

[0173] (Product name "G-1000", manufactured by Japan Soda) Hydroxyl value: 76 [KOH mg / g]

[0174] (a3) Hydroxyl-containing (meth)acrylates

[0175] • 2-Hydroxyethyl acrylate (HEA commercially available product, contains MEHQ 300ppm)

[0176] (a4) Aliphatic monohydric alcohols

[0177] ·1-Oc-OH

[0178] ·1-Dodecanool (Dd-OH)

[0179] (other)

[0180] • Carbamate esterification catalyst: Dibutyltin dilaurate

[0181] <Raw material used as a reaction solvent in the synthesis process>

[0182] (B) Alkyl methacrylate

[0183] Isoborneol acrylate (IBXA) is a commercially available product containing 100 ppm MEHQ.

[0184] • Commercially available 2-ethylhexyl acrylate (EHA) contains 15 ppm MEHQ.

[0185] <Raw materials in the mixing process>

[0186] (C) Photopolymerization initiator

[0187] ·4-Benzoyl-4'-methyldiphenyl sulfide (BMS)

[0188] (Product name "Omnirad BMS", manufactured by IGM RESINS) Benzophenone-based (hydrogen abstraction type) polymerization initiator

[0189] ·2,4-Diethylthioxanthone (DETX)

[0190] (Product name "KAYACURE DETX-S", manufactured by Nippon Kayaku Co., Ltd.) Thioxanone-based (hydrogen-extraction type) polymerization initiator

[0191] • (±)-Campoquinone (CQN)

[0192] ·Phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide (BTPO) (product name "Omnirad 819", manufactured by IGMRESINS) acylphosphine oxide polymerization initiator

[0193] ·2,4,6-Trimethylbenzoyl-diphenylphosphine oxide (TPO)

[0194] (Product name "Omnirad TPO", manufactured by IGM RESINS) Acylphosphine oxide polymerization initiator

[0195] (D) Organic peroxides (all of the following have a 10-hour half-life temperature above 100°C)

[0196] • tert-butyl hydroperoxide (tBPO)

[0197] • Cucurbitene hydroperoxide (CHPO)

[0198] (E) Amine compounds (polymerization accelerators)

[0199] Ethyl dimethylaminobenzoate (DMB)

[0200] (Tertiary amines with aromatic ring structures)

[0201] ·1,2,3,4,-Tetrahydroquinoline (THQ)

[0202] (Secondary amines with heterocyclic structures)

[0203] ·Dodecanedioic acid dihydrazide (DDH) (reference compound)

[0204] (F) Reducing agent for anaerobic curing

[0205] Saccharin (SAC)

[0206] (Synthesis example 1)

[0207] The synthesis process was carried out by performing a carbamate reaction at 60°C for 1 hour using the compounded components shown in Table 1, in the presence of (a1) to (a4) and a catalyst. It should be noted that the carbamate reaction was carried out in two stages by continuing the carbamate reaction of (a3) ​​and (a4) after the carbamate reaction of (a1) and (a2).

[0208] The values ​​in parentheses in Table 1 represent the relative molar ratios of the molecules of each component. These molar ratios are calculated based on the theoretical isocyanate group content of the (a1) isocyanate compound.

[0209] (Synthesis Examples 2 and 3)

[0210] Except for changing the mixing amounts shown in Table 1, the curable composition was synthesized in the same manner as in Example 1.

[0211] It should be noted that FT-IR analysis was performed on the reactants generated through the synthesis steps of Synthetic Examples 1-3 described above, and the results showed a value of 2260 cm⁻¹.-1 The absorption of nearby isocyanate groups disappears, and at 1730 cm⁻¹ -1 The increased absorption of the nearby carbonyl group confirms the synthesis of a compound with a carbamate bond.

[0212] [Table 1]

[0213]

[0214] The components of Synthetic Example 1 are Figure 1 The component with an average n value of 2. On the other hand, the components of synthetic examples 2-4 are... Figure 1 The average value of n in the equation becomes the component of 1.

[0215] (Each test case, each embodiment, and each comparative case)

[0216] Using the mixing amounts shown in Tables 2 to 6, the above-mentioned raw materials (B) to (F) were added to the compositions after each synthesis step and mixed to perform a mixing process. Tables 2 and 3 mainly show the mixing components used to investigate the effects of the above-mentioned components (D) to (F) on curing under anaerobic conditions.

[0217] It should be noted that the amount of each urethane (meth)acrylate resin in (A-1) to (A-4) is based on the total amount of each raw material used in the synthesis of each urethane (meth)acrylate resin.

[0218] [Table 2]

[0219]

[0220] [Table 3]

[0221]

[0222] [Table 4]

[0223]

[0224] [Table 5]

[0225]

[0226] [Table 6]

[0227]

[0228] As shown below, the curable compositions manufactured in the test examples, examples, and comparative examples were evaluated. Specifically, the electrical insulation resistance value of the cured products (cured films) formed by curing the manufactured curable compositions was measured.

[0229] <Cure Treatment>

[0230] like Figure 3 As shown, the curing process is carried out by performing the following operations, and then the insulation resistance value is measured.

[0231] Prepare to cover the back of a JIS II type comb-shaped substrate (rectangular, 35 μm copper thickness) with polyimide film adhesive tape (Nitto Denko No. 360UL, tape thickness m 0.06). Overlap two pieces of polyester tape (Nitto Denko N-300, tape thickness 0.10), each cut to 3 mm wide, onto the surface of the comb-shaped substrate along three sides (excluding the side with terminals). This tape is used to prevent the composition from dripping and to allow the composition to cure at a specified thickness (as a spacer). Then, mask the electrode area by covering it with the polyimide film adhesive tape, and subsequently, using the polyester tape as a spacer, apply each curable composition to one side of the comb-shaped substrate (35 μm copper thickness) with a thickness of 200 μm. Prepare two such samples.

[0232] Then, a 500W metal halide lamp was used to accumulate a light intensity of 3000 mJ / cm². 2 The method of irradiating a sample with ultraviolet light (the cured sample after being irradiated by light) is used to measure the intensity of the light.

[0233] Another sample was subjected to anaerobic curing under the anaerobic conditions described below. Specifically, first, a glass epoxy substrate (a substrate with one side completely covered by the aforementioned polyimide film adhesive tape) was prepared in a way that could block ultraviolet light. Next, the side of the glass epoxy substrate without adhesive tape was placed against the coated portion (the side coated with the curable composition) of each sample, thus subjecting the curable composition of each sample to an anaerobic state. Then, the two substrates were clamped together using two binder clips, with the comb-shaped substrate and the glass epoxy substrate subjected to compressive force in the thickness direction. This anaerobic state was maintained for 30 days, resulting in the anaerobic curing treatment (anaerobic-cured sample).

[0234] <Insulation resistance value>

[0235] Remove the adhesive tape covering the electrode portion from each test specimen that has undergone curing treatment (light irradiation or anaerobic curing) as described above, and weld ethylene-coated copper wires to the electrode portion. Then, apply a DC 100V voltage to the comb-shaped electrodes and measure the insulation resistance value of the three comb-shaped wires after 60 seconds.

[0236] It should be noted that the detailed evaluation methods and judgment criteria for Evaluation 1-1~1-3, Evaluation 1-a, Evaluation 2, and Evaluation 3 recorded in Tables 2 to 6 are as follows.

[0237] Evaluation 1-1: Internal insulation resistance value [Ω] of the anaerobic cured sample / substrate (after 4 hours)

[0238] Evaluation 1-2: Internal insulation resistance value [Ω] of the anaerobic cured sample / substrate (after 7 days)

[0239] Evaluation 1-3: Internal insulation resistance [Ω] of the anaerobic cured sample / substrate (after 1 month)

[0240] Evaluation 1-a: Curing properties of anaerobic-cured samples / parts away from copper wiring (after 1 month)

[0241] ( Figure 3 (The part surrounded by dashed lines in the bottommost diagram)

[0242] Visual inspection (Excellent: solidified, Good: partially unsolidified, Poor: residual liquid)

[0243] Evaluation 2: Insulation resistance value of the surface of the cured sample / substrate after light irradiation [Ω]

[0244] Evaluation 3: Time-dependent stability of the curable composition (liquid)

[0245] Add 50g of the curing composition to a 250mL light-proof plastic bottle, leave at room temperature, and observe the number of days until curing.

[0246] Glass transition temperature (Tg)

[0247] For the ultraviolet irradiation portions in Examples 1, 5-7, the glass transition temperature of the cured products was measured. The results are shown in Table 4. It should be noted that the glass transition temperature was determined using a dynamic viscoelasticity measuring device to read the tensile mode, vibration frequency of 1 Hz, heating rate of 5 °C / min, and the maximum value of tanδ.

[0248] <Energy Storage Modulus>

[0249] For the ultraviolet irradiation portions in Examples 1, 5-7, the storage modulus of the cured material at 25°C was measured. The results are shown in Table 4. It should be noted that the storage modulus was measured using a dynamic viscoelasticity measuring device, in tensile mode, with a heating rate of 5°C / min and a vibration frequency of 1Hz.

[0250] The evaluation results of the cured products are shown in Tables 2 to 6.

[0251] The evaluation results show that, compared with the cured product of the comparative example composition, the cured product formed by curing the curable compositions of each embodiment has a higher insulation resistance value not only in the light-exposed part but also in the part cured under anaerobic conditions.

[0252] Furthermore, as can be seen from the measurement results of glass transition temperature and storage modulus in Table 4, the cured products of each curable composition in Examples 1, 5 to 7 have moderate softness.

[0253] Conventional curable compositions intended for adhesive applications have resulted in relatively hard cured products. Therefore, if applied to electrical insulation applications in the electrical and electronic fields and subjected to repeated high and low temperatures, the stress generated by repeated expansion and contraction could cause the cured product to crack. For example, there are concerns about wiring breakage containing the cured product or cracking of the cured product itself. Therefore, simply applying conventional adhesive-oriented curable compositions to electrical insulation applications could predictably compromise product reliability in terms of insulation reliability.

[0254] Industrial availability

[0255] The curable composition of the present invention (curing composition) is used, for example, to coat at least a portion of the surface of an object to be coated with a cured material onto circuit components constituting electronic circuits, circuits, etc. It is then cured by light irradiation or under anaerobic conditions, and is suitable for use as a cured material while still attached to the object to be coated. The curable composition of the present invention is suitable, for example, as a curable composition for insulating coatings.

Claims

1. A curable composition for coating, comprising urethane (meth)acrylate resin, alkyl (meth)acrylate, photopolymerization initiator, organic peroxide, and amine compound.

2. The coating curing composition according to claim 1, wherein, The urethane (meth)acrylate resin is a product of the urethane esterification reaction of at least a diol compound, a trifunctional or higher isocyanate compound, and a hydroxyl-containing (meth)acrylate.

3. The coating curing composition according to claim 2, wherein, The diol compound comprises at least one of branched polyolefin diol and aliphatic polycarbonate diol.

4. The coating curing composition according to claim 2 or 3, wherein, The urethane (meth)acrylate resin is at least the product of the urethane reaction of the isocyanate compound, the diol compound, the hydroxyl-containing (meth)acrylate, and an aliphatic monohydric alcohol.

5. The coating curable composition according to claim 2 or 3, wherein, The alkyl methacrylate contains at least one of an alkyl methacrylate having a cyclic hydrocarbon structure in the molecule and an alkyl methacrylate having a chain hydrocarbon structure having 6 or more carbon atoms in the molecule.

6. The coating curable composition according to claim 2 or 3, wherein, The amine compound comprises at least one of dimethylaminobenzoate and 1,2,3,4,-tetrahydroquinoline.

7. A cured product, which is a cured product of the coating curing composition according to any one of claims 1 to 3, and which adheres to the object to be coated.

8. The solidified material according to claim 7 has a storage modulus of less than 100 MPa at 25°C.

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