Ultraviolet curable resin composition, cured product thereof, and electronic device including the cured product

Abstract

To provide a UV curable resin composition which gives a cured product improved in moisture proofness (reducing water vapor permeation), improved in adhesiveness with a substrate and improved in flexibility after being cured and which is used for securing moisture proofness and insulation in a terminal portion of a substrate on which an electronic component is disposed, the UV curable resin composition being curable at a room temperature or at a low temperature and having suitable low viscosity, a UV curable resin composition giving a cured product which is obtained by UV curing the resin composition, improved in moisture proofness (reducing water vapor permeation), improved in adhesiveness with a substrate and improved in flexibility after being cured, a cured product obtained from the UV curable resin composition and an electronic device including the cured product.SOLUTION: An ultraviolet curable resin composition contains a cyclopolymereizable monomer (A), a multifunctional thiol compound (B), a bifunctional (meth) acrylate compound (C) having a polymerizable unsaturated group in a side chain, and a polymerization initiator (D).SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to an ultraviolet-curable resin composition, a cured product thereof, and an electronic device including the cured product. [Background technology]

[0002] When electronic components such as semiconductors and display devices are mounted on a printed wiring board, a moisture-proof insulating layer may be formed to ensure the connection reliability of the electrical connections (terminals, etc.) The moisture-proof insulating layer that covers the terminals is formed by applying and curing a curable resin composition.

[0003] For example, Patent Document 1 describes an ultraviolet-curable insulating coating resin composition that contains a urethane (meth)acrylate oligomer (A) having a hydrogenated polyisoprene skeleton or a hydrogenated polybutadiene skeleton, a (meth)acrylate having an alicyclic skeleton (B), a photopolymerization initiator (C), and paraffin wax (D).

[0004] Patent Document 2 describes a photocurable resin composition containing (A) a resin having a polymerizable unsaturated group and a predetermined number average molecular weight, (B) a monomer having a polymerizable unsaturated group and an alicyclic hydrocarbon group, and (C) a photopolymerization initiator.

[0005] Patent Document 3 describes an ink for electronic devices that contains an N-vinyl compound, a thiol, and a polymerizable monomer other than the N-vinyl compound.

[0006] In recent years, in order to use the composition for moisture-proofing and insulation of the terminal portion of an OLED mounting substrate (such as a polyimide substrate), there has been a demand for a curable resin composition that can be cured at room temperature or at a low temperature and has an appropriately low viscosity and good dilutability from the viewpoints of workability, handling, and the like. In addition, the cured product is required to have performance such as moisture-proofing (low water vapor permeability), excellent adhesion to the substrate, and excellent flexibility depending on the intended use. [Prior art documents] [Patent documents]

[0007] Patent Document 1 Japanese Unexamined Patent Application Publication No. 2020-158674 Patent Document 2 Japanese Unexamined Patent Application Publication No. 2019-218478 Patent Document 3 Japanese Unexamined Patent Application Publication No. 2023-70947 Summary of the Invention Problems to be Solved by the Invention

[0008] The present invention provides an ultraviolet curable resin composition (hereinafter, may be referred to as "UV curable resin composition") used for ensuring moisture resistance and insulation of terminal portions of a substrate on which electronic components are arranged, and a cured product obtained by UV curing the resin composition. Specifically, the present invention is a UV curable resin composition that can be cured at room temperature or low temperature and has an appropriate low viscosity, and after curing, provides a cured product having high moisture resistance (low water vapor transmission rate), excellent adhesion to a substrate, and excellent flexibility. Another object of the present invention is to provide a cured product obtained from the UV curable resin composition, and an electronic device having the cured product. Means for Solving the Problems

[0009] As a result of intensive studies, the inventors have found that a UV curable resin composition containing a cyclopolymerizable monomer, a polyfunctional thiol compound, a bifunctional (meth)acrylate compound having a polymerizable unsaturated group in the side chain, and a polymerization initiator can solve the above problems. Based on such findings, further studies were conducted to complete the present invention.

[0010] That is, the present invention provides the following ultraviolet curable resin composition, a cured product thereof, and an electronic device including the cured product. Item 1. An ultraviolet curable resin composition comprising a cyclopolymerizable monomer (A), a polyfunctional thiol compound (B), a bifunctional (meth)acrylate compound (C) having a polymerizable unsaturated group in the side chain, and a polymerization initiator (D). Item 2. The ultraviolet curable resin composition according to Item 1, wherein the bifunctional (meth)acrylate compound (C) having a polymerizable unsaturated group in the side chain is a bifunctional urethane (meth)acrylate compound having a vinyl group in the side chain. Item 3. The ultraviolet curable resin composition according to Item 2, wherein the bifunctional urethane (meth)acrylate compound (C) having a vinyl group in the side chain is polybutadiene urethane (meth)acrylate. Item 4. The ultraviolet curable resin composition according to Item 3, wherein the polybutadiene urethane (meth)acrylate contains a compound represented by the formula (1). TIFF2025083216000001.tif34168(In the formula, R is the same or different and is a group represented by the formula (1A), TIFF2025083216000002.tif21168(In the formula, R 1 represents a divalent hydrocarbon group, and R 2 represents an alkylene group.) n represents an integer of 1 or more.) Item 5. The ultraviolet curable resin composition according to any one of Items 1 to 4, wherein the cyclopolymerizable monomer (A) is 2-(allyloxymethyl)acrylate (particularly, methyl 2-(allyloxymethyl)acrylate). Item 6. The ultraviolet curable resin composition according to any one of Items 1 to 5, wherein the polyfunctional thiol compound (B) is a thiol compound having 3 or more functional groups (particularly, pentaerythritol tetrakis(3-mercaptobutyrate)). Item 7. The ultraviolet curable resin composition according to any one of Items 1 to 6, further comprising a filler (E). Item 8. The ultraviolet curable resin composition according to Item 7, wherein the filler (E) contains talc. Item 9. The ultraviolet curable resin composition according to Item 7, wherein the filler (E) contains nano-sized talc. Item 10. A cured product of the ultraviolet curable resin composition according to any one of Items 1 to 9. Item 11. An electronic device in which a terminal portion of a substrate on which electronic components are arranged is coated with the cured product according to Item 10. Item 12. A method for manufacturing the electronic device according to Item 11, the method including a step of applying and curing the ultraviolet curable resin composition according to any one of Items 1 to 9 to a terminal portion of a substrate on which electronic components are arranged.

Advantages of the Invention

[0011] The UV curable resin composition of the present invention is usually a liquid composition and has appropriate low viscosity and good dilutability. Therefore, for example, it has excellent dischargeability from a dispenser and can uniformly coat an object. Further, since the UV curable resin composition can be cured by ultraviolet irradiation, high temperature conditions are not required. The cured product obtained by curing the UV curable resin composition is excellent in insulation properties, has high moisture resistance (low water vapor transmission rate), excellent adhesion to a substrate (especially polyimide), and further has excellent flexibility. Therefore, the UV curable resin composition is suitably used as a material for directly applying to a terminal portion of a substrate on which electronic components are arranged to ensure moisture resistance and insulation properties of the terminal portion. Further, since the cured product of the UV curable resin composition is excellent in flexibility, the cured product can follow the bending of the substrate while maintaining adhesion to the substrate. Further, by including an ion catcher in the UV curable resin composition of the present invention, the electrical conduction reliability (characteristics such as the ability to suppress deterioration of the terminal portion due to inorganic ion impurities in the cured product during use of the electronic device) is further improved.

Embodiments for Carrying Out the Invention

[0012] Hereinafter, the UV curable resin composition according to the present embodiment, its cured product, and an electronic device having the cured product will be described.

[0013] 1. UV curable resin composition The UV-curable resin composition of the present invention is characterized by containing a cyclopolymerizable monomer (A), a polyfunctional thiol compound (B), a bifunctional (meth)acrylate compound (C) having a polymerizable unsaturated group in the side chain, and a polymerization initiator (D). Optionally, it may further contain a filler (E) and other components as needed.

[0014] [Cyclopolymerizable monomer (A)] The UV-curable resin composition of the present invention contains a cyclopolymerizable monomer (A). The cyclopolymerizable monomer (A) means a monomer having two or more (particularly two) polymerizable unsaturated groups in the molecule and capable of undergoing an intramolecular cyclization reaction during polymerization to form a cyclic compound.

[0015] Typical examples of the cyclopolymerizable monomer (A) include 2-(allyloxy)acrylate esters. Specific examples thereof include alkyl 2-(allyloxy)acrylate esters such as methyl 2-(allyloxy)acrylate, ethyl 2-(allyloxy)acrylate, n-propyl 2-(allyloxy)acrylate, isopropyl 2-(allyloxy)acrylate, n-butyl 2-(allyloxy)acrylate, s-butyl 2-(allyloxy)acrylate, and t-butyl 2-(allyloxy)acrylate; 2-(allyloxy)acrylate esters having a ring structure such as cyclopentanyl 2-(allyloxy)acrylate, adamantyl 2-(allyloxy)acrylate, dicyclopentanyl 2-(allyloxy)acrylate, dicyclopentenyl 2-(allyloxy)acrylate, isobornyl 2-(allyloxy)acrylate, benzyl 2-(allyloxy)acrylate, naphthyl 2-(allyloxy)acrylate, and biphenyl 2-(allyloxy)acrylate. Among them, methyl 2-(allyloxy)acrylate, dicyclopentenyl 2-(allyloxy)acrylate, naphthyl 2-(allyloxy)acrylate, and biphenyl 2-(allyloxy)acrylate are preferred from the viewpoints of improving hydrophobicity, imparting high moisture resistance, and having an excellent viscosity reduction effect. The cyclopolymerizable monomer (A) can be used alone or in combination of two or more thereof.

[0016] The cyclic polymerizable monomer (A) has a low viscosity, is excellent in the property of diluting oligomers and the like, and exhibits high radical polymerizability, so it functions effectively as a reactive diluent. Further, the cyclic polymerizable monomer (A) cyclizes by polymerization to form a polymer having a ring structure in the main chain, that is, a polymer having a structure in which tetrahydrofuran rings are linked by a carbon chain (methylene group). Since the cured product of the UV curable resin composition of the present invention contains such a polymer, it has good flexibility, high adhesion to a substrate, and high moisture resistance (low water vapor permeability).

[0017] As the cyclic polymerizable monomer (A), commercially available products can be used. Specific examples thereof include AOMA (registered trademark) and the like.

[0018] The content of the cyclic polymerizable monomer (A) in the UV curable resin composition of the present invention is usually 10 to 60% by mass, preferably 15 to 50% by mass, more preferably 20 to 40% by mass with respect to the total amount of the UV curable resin composition.

[0019] [Polyfunctional thiol compound (B)] The UV curable resin composition of the present invention contains a polyfunctional thiol compound (B). The polyfunctional thiol compound (B) is a compound having two or more thiol groups, and is one of the components used to impart adhesion to a substrate and flexibility to the cured product of the UV curable resin composition of the present invention.

[0020] Specific examples of the polyfunctional thiol compound (B) include aliphatic dithiols such as hexane-1,6-dithiol, decane-1,10-dithiol, dimercapto diethyl ether, and dimercapto diethyl sulfide; aromatic dithiols such as xylylene dimercaptan, 4,4'-dimercapto diphenyl sulfide, and 1,4-benzenedithiol; Poly(mercaptoacetate) of polyhydric alcohols such as ethylene glycol bis(mercaptoacetate), polyethylene glycol bis(mercaptoacetate), propylene glycol bis(mercaptoacetate), glycerin tris(mercaptoacetate), trimethylolethane tris(mercaptoacetate), trimethylolpropane tris(mercaptoacetate), pentaerythritol tetrakis(mercaptoacetate), dipentaerythritol hexakis(mercaptoacetate); Poly(3-mercaptopropionate) of polyhydric alcohols such as ethylene glycol bis(3-mercaptopropionate), polyethylene glycol bis(3-mercaptopropionate), propylene glycol bis(3-mercaptopropionate), glycerin tris(3-mercaptopropionate), trimethylolethane tris(mercapto propionate), trimethylolpropane tris(3-mercaptopropionate), pentaerythritol tetrakis(3-mercaptopropionate), dipentaerythritol hexakis(3-mercaptopropionate); and, Examples thereof include poly(mercaptobutyrate) of polyhydric alcohols such as trimethylolpropane tris(3-mercaptobutyrate), 1,4-bis(3-mercaptobutyryloxy)butane, 1,3,5-tris(3-mercaptobutyloxyethyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, pentaerythritol tetrakis(3-mercaptobutyrate). The polyfunctional thiol compound (B) can be used alone or in combination of two or more thereof.

[0021] Among these polyfunctional thiol compounds (B), from the viewpoint of imparting appropriate flexibility, adhesion to a substrate, and touch-dry property after curing the UV curable resin composition of the present invention, a thiol compound having 3 or more functional groups (particularly 3 or 4 functional groups) is preferable, and a thiol compound having 4 or more functional groups (particularly 4 functional groups) is more preferable. Further, the polyfunctional thiol compound (B) is preferably a primary or secondary thiol compound, and from the viewpoint of the storage stability of the UV curable resin composition, it is more preferably a secondary thiol compound. Furthermore, it is particularly preferable that the polyfunctional thiol compound (B) is a 4-functional and secondary thiol compound.

[0022] Among the above specific examples, poly(methyl mercaptobutyrate) of polyhydric alcohol is preferable, trimethylolpropane tris(3-mercaptobutyrate), 1,3,5-tris(3-mercaptobutyloxyethyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, and pentaerythritol tetrakis(3-mercaptobutyrate) are more preferable, and pentaerythritol tetrakis(3-mercaptobutyrate) is particularly preferable.

[0023] As the polyfunctional thiol compound (B), commercially available products can be used. Specific examples thereof include Karenz MT (registered trademark; the same shall apply hereinafter) PE1, Karenz MT BD1, Karenz MT NR1, Karenz MT TPMB (manufactured by Resonac Co., Ltd.), and the like.

[0024] The content of the polyfunctional thiol compound (B) in the UV curable resin composition of the present invention is usually 0.5 to 20% by mass, preferably 1 to 15% by mass, and more preferably 2 to 10% by mass with respect to the total amount of the UV curable resin composition.

[0025] [Bifunctional (meth)acrylate compound (C) having a polymerizable unsaturated group in the side chain] The UV curable resin composition of the present invention contains a bifunctional (meth)acrylate compound (C) having a polymerizable unsaturated group in the side chain. In the bifunctional (meth)acrylate compound (C), examples of the polymerizable unsaturated group include a group having a polymerizable carbon-carbon double bond, a group having a carbon-carbon triple bond, etc., and preferably a vinyl group, an allyl group, etc. Further, (meth)acrylate means acrylate (acrylic acid ester) and / or methacrylate (methacrylic acid ester), and a bifunctional (meth)acrylate compound means a compound having two (meth)acrylate moieties in the molecule. The bifunctional (meth)acrylate compound (C) is usually a chain oligomer molecule and has (meth)acrylate moieties at both ends thereof.

[0026] As the bifunctional (meth)acrylate compound (C) having a polymerizable unsaturated group in the side chain, a bifunctional urethane (meth)acrylate compound having a vinyl group in the side chain is preferable, and polybutadiene urethane (meth)acrylate is more preferable. This polybutadiene urethane (meth)acrylate is a polybutadiene (meth)acrylate resin (oligomer) having (meth)acrylic groups at both ends of polybutadiene via urethane bonds.

[0027] Examples of the polybutadiene urethane methacrylate include a compound represented by the formula (1). TIFF2025083216000003.tif33168(In the formula, R is the same or different and is a group represented by the formula (1A), TIFF2025083216000004.tif22168(wherein R 1 represents a divalent hydrocarbon group, and R 2 represents an alkylene group.) n represents an integer of 1 or more.)

[0028] In the formula (1), n means the degree of polymerization of butadiene and can be arbitrarily set within the range in which the bifunctional (meth)acrylate compound (C) has the properties of the above oligomer.

[0029] In formula (1A), R 1 Examples of the divalent hydrocarbon group represented by 1 include divalent groups obtained by removing two hydrogen atoms from acyclic hydrocarbons, cyclic hydrocarbons (including alicyclic hydrocarbons, aromatic hydrocarbons, etc.). Examples of the divalent group obtained by removing two hydrogen atoms from an acyclic hydrocarbon include, for example, linear or branched alkylene groups having 1 to 10 carbon atoms. Specifically, a methylene group (-CH 2 -), a dimethylene group (-CH-CH 2 -), a trimethylene group, a tetramethylene group, a dimethylmethylene group, etc. are included.

[0030] Examples of the divalent group obtained by removing two hydrogen atoms from an alicyclic hydrocarbon include, for example, divalent groups obtained by removing two hydrogen atoms from a monocyclic or polycyclic condensed alicyclic hydrocarbon. Specifically, a cyclopropanediyl group, a cyclobutanediyl group, a cyclopentanediyl group, a cyclohexane diyl, a cycloheptanediyl group, etc. are included. Examples of the divalent group obtained by removing two hydrogen atoms from an aromatic hydrocarbon include, for example, divalent groups obtained by removing two hydrogen atoms from a monocyclic or polycyclic condensed aromatic hydrocarbon. Specifically, a benzenediyl group, a toluenediyl group, a xylenediyl group, a naphthalenediyl group, etc. are included.

[0031] Among these, as R 1 , a divalent group obtained by removing two hydrogen atoms from a monocyclic aromatic hydrocarbon is preferable, a benzenediyl group or a toluenediyl group is more preferable, and a toluenediyl group is particularly preferable.

[0032] In formula (1A), examples of the alkylene group represented by R 2 include linear or branched alkylene groups having 1 to 10 (preferably 2 to 6) carbon atoms. Specifically, a methylene group (-CH 2 -), a dimethylene group (-CH 2 -CH 2-), a trimethylene group, a tetramethylene group, a dimethylmethylene group, etc. may be mentioned, and a dimethylene group is preferable.

[0033] The number average molecular weight (Mn) of the bifunctional (meth)acrylate compound (C) having a polymerizable unsaturated group in the side chain is usually 1500 to 4000, preferably 2000 to 3000, and more preferably 2300 to 2700. This number average molecular weight can be measured using gel permeation chromatography (standard polymer: polystyrene conversion, eluent: THF).

[0034] The viscosity of the bifunctional (meth)acrylate compound (C) is usually 500 to 4000 poise / 45 °C, and further 1000 to 3000 poise / 45 °C. The viscosity can be measured using a cone and plate viscometer. Also, its acrylic equivalent is usually 1000 to 3000 g / eq, and further 1600 to 2300 g / eq. Its glass transition temperature (Tg) is usually -20 to 0 °C, and further -15 to -5 °C.

[0035] The bifunctional (meth)acrylate compound (C) can be used alone or in combination of two or more of these.

[0036] When curing the UV curable resin composition of the present invention, the bifunctional (meth)acrylate compound (C) having a polymerizable unsaturated group in the side chain and the polyfunctional thiol compound (B) can react to form a crosslinked structure. The cured product obtained thereby has excellent adhesion to the substrate, has hydrophobicity, so has a low water vapor permeability and has appropriate flexibility.

[0037] As the bifunctional (meth)acrylate compound (C) having a polymerizable unsaturated group in the side chain, commercially available products can be used. Specific examples thereof include TE-2000 (manufactured by Nippon Soda Co., Ltd.).

[0038] The content of the bifunctional (meth)acrylate compound (C) having a polymerizable unsaturated group in the side chain in the UV-curable resin composition of the present invention is usually 20 to 80% by mass, preferably 30 to 70% by mass, and more preferably 40 to 60% by mass with respect to the total amount of the UV-curable resin composition.

[0039] [Polymerization initiator (D)] The UV-curable resin composition of the present invention contains a polymerization initiator (D). The polymerization initiator (D) is not particularly limited as long as it can initiate a radical polymerization reaction. For example, oxime compounds, alkylphenone compounds, acylphosphine oxide compounds, aromatic onium salt compounds, organic peroxides, thioxanthone compounds, hexaaryl bisimidazole compounds, borate compounds, azinium compounds, titanocene compounds, active ester compounds, compounds having a carbon-halogen bond, and alkylamines can be mentioned.

[0040] From the viewpoint of UV curability, it is preferable that the polymerization initiator contains at least one selected from the group consisting of alkylphenone compounds, acylphosphine oxide compounds, and thioxanthone compounds.

[0041] Examples of the alkylphenone compound include α-hydroxyalkylphenone compounds, α-aminoalkylphenone compounds, and benzyl ketal alkylphenone compounds.

[0042] Examples of the α-hydroxyalkylphenone compound include 2,2'-dihydroxy-2,2'-dimethyl-1,1'-[methylenebis(4,1-phenylene)]bis(propan-1-one), 1-[4-(2-hydroxyethoxy)phenyl]-2-methyl-2-hydroxy-1-propanone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, and 1-hydroxycyclohexyl phenyl ketone.

[0043] Examples of α-aminoalkylphenone compounds include 2-methyl-1-phenyl-2-morpholinopropan-1-one, 2-methyl-1-[4-(hexyl)phenyl]-2-morpholinopropan-1-one, 2-ethyl-2-dimethylamino-1-(4-morpholinophenyl)butan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butan-1-one, 2-dimethylamino-2-(4-methylbenzyl)-1-(4-morpholin-4-yl-phenyl)butan-1-one, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, 2-(dimethylamino)-2-(4-methylbenzyl)-1-(4-morpholinophenyl)butan-1-one, and 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]butan-1-one.

[0044] Examples of benzyl ketal alkylphenone compounds include, for example, the alkylphenone compound 2,2-dimethoxy-2-phenylacetophenone.

[0045] Examples of commercially available alkylphenone compounds include, for example, Omnirad 651, Omnirad 184, Omnirad 1173, Omnirad 2959, Omnirad 127, Omnirad 907, Omnirad 369, Omnirad 369E, and Omnirad 379 (manufactured by IGM Resins B.V.).

[0046] Specific examples of acylphosphine oxide compounds include 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethyl-pentylphosphine oxide, and the like.

[0047] Examples of commercially available acylphosphine oxide compounds include Omnirad 819 (manufactured by IGM Resins B.V.).

[0048] Examples of the thioxanthone compound include thioxanthone, 2-isopropylthioxanthone, 4-isopropylthioxanthone, 2-chlorothioxanthone, and 2,4-dichlorothioxanthone.

[0049] As the polymerization initiator (D), only one of these or a combination of two or more thereof can be used.

[0050] The content of the polymerization initiator (D) in the UV curable resin composition of the present invention is usually 0.2 to 8.0% by mass, preferably 0.5 to 6.0% by mass, more preferably 1.0 to 5.0% by mass with respect to the total amount of the UV curable resin composition.

[0051] [Filler (E)] The UV curable resin composition of the present invention may further contain a filler (E). By including the filler (E), the water vapor permeability of the cured product can be further reduced.

[0052] The filler (E) may be either an inorganic filler or an organic filler, preferably an inorganic filler. Examples of the inorganic filler include talc, mica, kaolin, glass flake, silica (silicon dioxide), alumina, clay compound (clay), barium sulfate, calcium carbonate, hydrotalcite, etc. Among them, talc having a plate-like particle shape and a Mohs hardness of 1 is preferable. Talc can effectively suppress the permeation of water vapor in the cured product due to its shape and arrangement, and can relieve the internal stress generated by the curing shrinkage during UV curing and prevent a decrease in the adhesion strength. Further, even if added due to its low Mohs hardness, it does not significantly impair the flexibility of the cured product.

[0053] As the talc, those whose surfaces are chemically or physically surface-treated with a silane coupling agent or the like can be used. By this, it is possible to impart affinity, dispersibility, etc. to a resin or the like, or to impart hydrophobicity. In particular, talc treated with a silane coupling agent having a methacryl group (methacryl silane treatment) is preferable.

[0054] The average particle diameter (D50) of the filler (E) (especially talc) is usually 0.1 to 50 μm, preferably 0.5 to 40 μm. Among them, nano-sized talc is recommended, and its average particle diameter (D50) is usually 0.1 to 1.0 μm, preferably 0.2 to 0.8 μm. This average particle diameter can be measured using the laser diffraction method.

[0055] Examples of commercially available products of the filler (E) include D-600, D-800, D-1000, FG-15, D-600C3-BM53, D-800C3-BM53, D-1000C3-BM53, FG-15C3-BM53 (nano ace series), SG-2000 (manufactured by Nippon Talc Co., Ltd.), etc.

[0056] When the UV curable resin composition of the present invention contains the filler (E), the content of the filler (E) in the composition is usually 2 to 50% by mass, preferably 5 to 30% by mass, more preferably 10 to 20% by mass with respect to the total amount of the UV curable resin composition.

[0057] [Other components] The UV curable resin composition of the present invention may further contain components (additives) such as a polymerization inhibitor, a surfactant, an organic solvent, a co-sensitizer, an ultraviolet absorber, an antioxidant, a non-cyclized polymerizable monomer, an ion catcher, a coupling agent, and a tackifier, as necessary, within the range where the effects of the present invention can be exhibited. For example, the energization reliability of a cured product obtained by adding an ion catcher to a UV-curable resin composition is further improved. When energizing (applying a charge) to metal (copper, aluminum, etc.) terminals encapsulated with the cured product, inorganic ion impurities (inorganic ions such as sulfate ions and chloride ions) in the cured product may elute (corrode) the metal, causing the resistance value of the circuit to increase rapidly, or may cause a short circuit due to metal migration. By including an ion catcher in the UV-curable resin composition, these inorganic ion impurities can be effectively captured, so that problems caused by elution (corrosion) of the electrodes can be avoided or delayed. That is, the energization reliability of the circuit can be further improved.

[0058] Examples of the ion catcher include, as a hydrotalcite-based ion catcher, Indigirite Mg 2 Al 2 [(CO 3 ) 4 (OH) 2 ·15H 2 O, Fe 2 +4Al 2 [(OH) 12 CO 3 ·3H 2 O, Quintinite Mg 4 Al 2 (OH)12CO 3 ·H 2 O, Manasseite Mg 6 Al 2 [(OH) 16 CO 3 ·4H 2 O, SjOegrenite Mg 6 Fe 3 +2[(OH) 16 CO 3 ·4H 2 O, Zaccagnaite Zn 4 Al 2 (CO 3 )(OH) 12 ·3H 2 O, Desautelsite Mg 6 Mn 3 +2[(OH) 16 CO3 ·4H 2 O, Hydrotalcite Mg 6 Al 2 [(OH) 16 CO 3 ·4H 2 O, Pyroaurite Mg 6 Fe 3 +2[(OH) 16 CO 3 ·4H 2 O, Reevesite Ni 6 Fe 3 +2[(OH) 16 CO 3 ·4H 2 O, Stichtite Mg 6 Cr 2 [(OH) 16 CO 3 ·4H 2 O, Takovite Ni 6 Al 2 [(OH) 16 CO 3 ·4H 2 O and the like can be mentioned. Examples of commercially available products include synthetic hydrotalcite-like compounds such as Alcamizer, DHT-4A, DHT-4A, DHT-4A-2, DHT-4C, Kyoward 500, Kyoward 1000, and HT-1, HT-7, HT-P of the STABIACE series manufactured by Sakai Chemical Industry Co., Ltd.

[0059] Examples of ion catchers other than hydrotalcite-based ones include inorganic particles composed of Zr-based compounds, inorganic particles composed of Sb-based compounds, inorganic particles composed of Bi-based compounds, etc. Also, inorganic particles composed of a binary system of Sb-based compounds and Bi-based compounds, inorganic particles composed of a binary system of Mg-based compounds and Al-based compounds, inorganic particles composed of a binary system of Zr-based compounds and Bi-based compounds, inorganic particles composed of a ternary system of Zr-based compounds, Mg-based compounds, and Al-based compounds, etc. can be mentioned. Examples of commercially available products include IXE-100, IXE-300, IXE-500, IXE-550, IXE-800, IXE-600, IXE-6107, IXE-6136, IXEPLAS-A1, IXEPLAS-B1, etc. manufactured by Toagosei Co., Ltd. These ion catchers may be used alone or in combination of two or more.

[0060] When the UV curable resin composition of the present invention contains an ion catcher, the content of the ion catcher in the composition is usually 0.1 to 20% by mass, preferably 1 to 10% by mass, based on the total amount of the UV curable resin composition.

[0061] [Preparation of UV Curable Resin Composition] The UV curable resin composition of the present invention can be prepared by mixing the above-described cyclopolymerizable monomer (A), polyfunctional thiol compound (B), bifunctional (meth)acrylate compound (C) having a polymerizable unsaturated group in the side chain, and polymerization initiator (D), and if necessary, further filler (E), other components, etc., and then finely dispersing the filler using a disperser such as a three-roll mill or a bead mill.

[0062] The UV curable resin composition of the present invention is usually a liquid composition, and its viscosity is, for example, 1.0 to 15 poise / 25 °C, preferably 2.0 to 13 poise / 25 °C, more preferably 5.0 to 10 poise / 25 °C. The viscosity is measured in accordance with 10 "Viscosity Measurement Method by Cone-Plate Rotational Viscometer" of JIS Z 8803:2011, at 25 °C, 50 rpm, as a 10-second value, using a 3°×R14 or 1°34’×R24 as the cone and rotor, and can be measured using a cone-plate type viscometer.

[0063] As a preferred embodiment of the UV-curable resin composition of the present invention, there is provided a composition containing, as component (A), AOMA; as component (B), a trifunctional or tetrafunctional secondary thiol compound; as component (C), a polybutadiene urethane (meth) acrylate (particularly, a compound represented by formula (1)); and as component (D), at least one selected from the group consisting of an alkylphenone compound and a thioxanthone compound.

[0064] As another preferred embodiment of the UV-curable resin composition of the present invention, there is provided a composition further containing, as component (E), nano-sized talc in the above composition.

[0065] 2. Application of the UV curable resin composition to a substrate The UV-curable resin composition of the present invention is widely used for forming a cured product by applying it onto a substrate. In particular, the UV-curable resin composition is applied to a terminal portion on a substrate on which electronic components such as LEDs and OLEDs are disposed, and is subjected to a curing treatment to form a cured product (insulating and moisture-proof layer) that coats the terminals on the substrate. Here, the terminal means a connection portion such as a metal wire (lead wire) of an element such as a resistor, a metal portion (wiring) for electrically connecting a semiconductor element to the outside, a screw for connecting an electric wire to an electric device or connecting electric devices to each other, or a projection (lug) for soldering.

[0066] The substrate to be applied may be any substrate having the above terminal portion, and known substrates can be used. Examples of the substrate include a rigid printed circuit board, a flexible printed circuit board, and a rigid-flexible printed circuit board. Examples of the substrate material include a polyimide substrate, a glass epoxy substrate, a ceramic substrate, and a polyethylene terephthalate substrate, among which a polyimide substrate is preferred. The substrate may be single-layer or multi-layer.

[0067] The terminals (metal wires, wirings, etc.) provided on the substrate are made of a conductive metal (for example, copper). Examples of the electronic components include semiconductor chips, capacitors, and transistors.

[0068] The UV curable resin composition of the present invention is applied to the terminal portion on the substrate. The application method is not particularly limited, but a known coating method, and among them, a dispensing method capable of precisely controlling the range and thickness of the insulating layer and the moisture-proof layer is preferable.

[0069] Next, the substrate to which the UV curable resin composition of the present invention is applied is irradiated with ultraviolet rays (UV) for curing. The peak wavelength of the ultraviolet rays is usually 200 to 450 nm, preferably 250 to 420 nm, and more preferably 300 to 405 nm. Examples of the light source for ultraviolet irradiation include UV-LED (light emitting diode), UV-LD (laser diode), mercury lamp, metal halide lamp, ultraviolet fluorescent lamp, etc. Among them, from the viewpoints of small size, long life, high efficiency, etc., UV-LED and UV-LD are preferable.

[0070] The thickness (film thickness) of the cured product formed on the substrate is usually 30 to 300 μm, preferably 50 to 150 μm. This thickness can be measured using a micrometer.

[0071] Thus, an electronic device in which the terminal portion on the substrate is covered with a cured product (insulating and moisture-proof layer) is manufactured. The cured product of the present invention is excellent in insulation and moisture-proof properties (low water vapor permeability), has appropriate flexibility, and is excellent in adhesion to the base material. In addition, since it has good touch dryness, adhesion of foreign substances to the surface of the cured product can be prevented.

Examples

[0072] Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

[0073] (1) Preparation of UV curable resin composition With the composition and ratio described in Table 1 below, after mixing each component, a filler or the like was finely dispersed using a disperser such as a three-roll mill or a bead mill, and the resulting composition was filtered through a filter with an opening diameter of 10 μm, and then defoamed using a centrifugal defoamer at 1800 rpm for 2 minutes, whereby the ultraviolet curable resin compositions of Examples 1 to 2 and Comparative Examples 1 to 5 were respectively prepared. The numerical values in Table 1 mean "parts by mass" unless otherwise specified.

[0074] (2) Viscosity of the ultraviolet curable resin composition The viscosity of the obtained ultraviolet curable resin composition was measured. The results are shown in Table 1.

[0075] <Viscosity> The viscosities of the ultraviolet curable resin compositions of Examples 1 to 2 and Comparative Examples 1 to 5 were measured as follows. In accordance with Section 10 "Viscosity measurement method using a conical - plate rotational viscometer" of JIS Z 8803:2011, at 25 °C, 50 rpm, and the 10 - second value, using a 3°×R14 or 1°34’×R24 as the cone - rotor, the viscosity was measured using a cone - plate type viscometer (TVE - 33H, manufactured by Toki Sangyo Co., Ltd.).

[0076] (3) Formation of the cured film and evaluation of the cured product A cured film was formed on a substrate, and the following evaluations were performed on the obtained cured product. The results are shown in Table 1.

[0077] <Adhesion to the substrate (180° peel strength test)> On a polyimide film (Kapton 300H, manufactured by Toray DuPont Co., Ltd.) with a size of 250 mm×100 mm and a thickness of 75 μm (without surface treatment), the ultraviolet curable resin compositions of Examples 1 to 2 and Comparative Examples 1 to 6 were respectively applied using an applicator so that the film thickness after curing was 100 μm, and irradiated with light at 365 nm and 2000 mJ / cm 2 to cure the coating film. The obtained cured product was formed into a polyimide film, which was cut into strips of 200 mm × 10 mm. It was attached to a 250 mm × 100 mm, 1.0 mm thick stainless steel plate (SUS304) with double-sided tape (manufactured by 3M Japan Co., Ltd., Y-4920, adhesive force: 40 N) so that the cured product side was in contact with the double-sided tape. After handling well with fingers to make the double-sided tape and the cured product adhere tightly, one end of the polyimide film was peeled off by hand about 20 mm from the cured product in advance, and the peeled-off part was used as a test piece. Using a tensile testing machine (AG-X, manufactured by Shimadzu Corporation), the test piece was fixed vertically to one clamp, and the pre-peeled polyimide film was attached to the other clamp. The 180° peel strength at 25°C was measured under the conditions of a peel rate of 60 mm / min and a peel distance of 150 mm, and the adhesion between the polyimide film and the cured product was evaluated according to the following criteria.

[0078] (Evaluation Criteria) 180° peel strength of 4 N / cm or more: ○ 180° peel strength of less than 4 N / cm: ×

[0079] <Flexibility (Tensile Test)> On a fluororesin film (manufactured by AGC) with a size of 250 mm × 100 mm and a film thickness of 25 μm, the ultraviolet curable resin compositions of Examples 1 to 2 and Comparative Examples 1 to 6 were respectively applied with an applicator so that the film thickness after curing was 100 μm, and irradiated with light at 365 nm and 2000 mJ / cm 2 by an ultraviolet curing LED (FE400, manufactured by Phoseon). After peeling the obtained cured product from the fluororesin film, the cut-out part into strips of 50 mm × 10 mm was used as a test piece. Using a tensile testing machine (AG-X, manufactured by Shimadzu Corporation), a tensile test was carried out at a distance between grips of 10 mm and a speed of 50 mm / min, and the elongation at break at 25°C was measured, and the flexibility was evaluated according to the following criteria.

[0080] Elongation at break (%) = Distance between grips when the test piece breaks / Distance between grips before the start of tension (10 mm) (Evaluation Criteria) Elongation at break of 200% or more: ○ Breaking point elongation less than 200%: ×

[0081] <Moisture resistance (water vapor permeability test)> On a fluororesin film (manufactured by AGC Inc.) with a size of 250 mm × 100 mm and a film thickness of 25 μm, the ultraviolet curable resin compositions of Examples 1 to 2 and Comparative Examples 1 to 6 were each applied with an applicator so that the film thickness after curing was 100 μm, and irradiated with light at 365 nm and 2000 mJ / cm 2 using an ultraviolet curing LED (FE400, manufactured by Foseon). After peeling the cured product obtained therefrom from the fluororesin film, a circular piece with a diameter of Φ70 mm was cut out as a test piece, and the water vapor permeability was measured under the conditions of a temperature of 40°C and a relative humidity of 90%RH using a moisture permeation cup (manufactured by Yasuda Seiki Seisakusho, No. 318) based on the JIS Z 0208 cup method, and the moisture resistance was evaluated according to the following criteria.

[0082] (Evaluation criteria) Water vapor permeability 70 g / (m 2 ·24 hr) or less: ○ Water vapor permeability exceeding 70 g / (m 2 ·24 hr): ×

[0083] <Touch dryness> On a polyimide film (Kapton 300H, manufactured by Toray DuPont Co., Ltd.) with a size of 250 mm × 100 mm and a thickness of 75 μm (without surface treatment), the ultraviolet curable resin compositions of Examples 1 to 2 and Comparative Examples 1 to 6 were each applied with an applicator so that the film thickness after curing was 100 μm, and irradiated with light at 365 nm and 2000 mJ / cm 2 using an ultraviolet curing LED (FE400, manufactured by Foseon). The surface of the cured product obtained therefrom was touched for 3 seconds with a strength such that the entire fingertip of the index finger was in contact, and the touch dryness was evaluated according to the following criteria.

[0084] (Evaluation criteria) No feeling of stickiness: ○ Feeling of stickiness: ×

[0085]

Table 1

[0086] *1 AOMA (methyl 2-(allyloxymethyl)acrylate: cyclic polymerizable monomer) (manufactured by Nippon Shokubai Co., Ltd.) *2 Light Ester IB-X (isobornyl methacrylate: number of functional groups 1) (manufactured by Kyoeisha Chemical Co., Ltd.) *3 LA (lauryl acrylate: number of functional groups 1) (manufactured by Osaka Organic Chemical Industry Co., Ltd.) *4 KAYARAD R-604 (dioxane acrylate: number of functional groups 2) (manufactured by Nippon Kayaku Co., Ltd.) *5 Karenz MT PE1 (pentaerythritol tetrakis(3-mercaptobutyrate): 4-functional secondary thiol compound) (manufactured by Resonance Co., Ltd.) *6 TE-2000 (polybutadiene acrylate resin having (meth)acrylic groups at both ends of polybutadiene via urethane bonds) (manufactured by Nippon Soda Co., Ltd.) *7 (N-vinyl-ε-caprolactam) (manufactured by Fujifilm Wako Pure Chemical Corporation) *8 Omnirad 379 (2-(dimethylamino)-2-(4-methylbenzyl)-1-(4-morpholinophenyl)-butan-1-one) (manufactured by IGM Resins B.V.) *9 D-600C3-BM53 (methacryl-silane-treated talc: nano-sized talc (D50 = 0.6 μm)) (manufactured by Nippon Talc Co., Ltd.)

[0087] From the results in Table 1, it was confirmed that the ultraviolet curable resin compositions of Examples 1 and 2 had appropriate viscosities, and the cured products were excellent in adhesion to the substrate (with a large 180° peel strength), excellent in flexibility (with a large elongation rate in the tensile test), and high in moisture resistance (with a sufficiently low water vapor transmission rate). On the other hand, in Comparative Example 1, since the polyfunctional thiol compound (B) was not contained in the composition, it was confirmed that the obtained cured product was inferior in adhesion to the substrate, flexibility, and moisture resistance compared to the cured product of Example 1. In Comparative Example 2, an N-vinyl compound was used instead of the bifunctional (meth)acrylate compound (C) having a polymerizable unsaturated group in the side chain, which resulted in poor curing and no cured product being obtained. Therefore, the cured product could not be evaluated. In Comparative Examples 3 to 5, an acrylic monomer that does not undergo cyclopolymerization was used in place of AOMA (cyclopolymerizable monomer (A)) in the composition. Therefore, it was confirmed that the resulting cured products were all significantly inferior in adhesion to substrates, flexibility, and moisture resistance to the cured product of Example 1. Furthermore, the cured products of Examples 1 and 2 also had good dryness to the touch, whereas the cured product of Comparative Example 1 had poor dryness to the touch.

[0088] <Examples 3 and 4> Ion catcher (Kyowa Chemical Industry Co., Ltd.) 、 Except for adding 10 parts of DHT-4A, ultraviolet-curable resin compositions are prepared in the same manner as in Examples 1 and 2, and cured products are prepared using the compositions (Examples 3 and 4, respectively). When these are evaluated in the same manner as above, the adhesion, flexibility, moisture resistance, and dryness to the touch are as good as in Examples 1 and 2, and further, the current reliability is improved compared to Examples 1 and 2. This is thought to be because the ion catcher captures inorganic ion impurities in the cured product, effectively suppressing the deterioration of the terminals. [Industrial Applicability]

[0089] The UV-curable resin composition of the present invention is UV-curable and has an appropriate low viscosity, and the cured product thereof has high moisture resistance (low water vapor permeability), excellent adhesion to a substrate, excellent flexibility, and excellent dryness to the touch. Therefore, the UV-curable resin composition is suitably used as a material for ensuring the moisture resistance and insulation of the terminal portion by directly applying it to the terminal portion of a substrate on which an electronic component is arranged.

Claims

1. An ultraviolet curable resin composition comprising a cyclic polymerizable monomer (A), a polyfunctional thiol compound (B), a bifunctional (meth)acrylate compound (C) having a polymerizable unsaturated group in the side chain, and a polymerization initiator (D).

2. The ultraviolet curable resin composition according to claim 1, wherein the bifunctional (meth)acrylate compound (C) having a polymerizable unsaturated group in the side chain is a bifunctional urethane (meth)acrylate compound having a vinyl group in the side chain.

3. The ultraviolet curable resin composition according to claim 2, wherein the bifunctional urethane (meth)acrylate compound (C) having a vinyl group in the side chain is polybutadiene urethane (meth)acrylate.

4. The ultraviolet curable resin composition according to claim 3, wherein the polybutadiene urethane (meth)acrylate contains a compound represented by formula (1). (In the formula, R is the same or different and is a group represented by formula (1A), (wherein, R １ represents a divalent hydrocarbon group, and R ２ represents an alkylene group.) n represents an integer of 1 or more.)

5. The ultraviolet curable resin composition according to claim 1, wherein the cyclic polymerizable monomer (A) is 2-(allyloxymethyl)acrylate.

6. The ultraviolet curable resin composition according to claim 1, wherein the polyfunctional thiol compound (B) is a thiol compound having three or more functional groups.

7. The ultraviolet curable resin composition according to claim 1, further comprising a filler (E).

8. The ultraviolet curable resin composition according to claim 7, wherein the filler (E) contains talc.

9. The ultraviolet curable resin composition according to claim 7, wherein the filler (E) contains nano-sized talc.

10. A cured product of the ultraviolet curable resin composition according to any one of claims 1 to 9.

11. An electronic device in which a terminal portion of a substrate on which an electronic component is disposed is coated with the cured product according to claim 10.

12. A method for manufacturing the electronic device according to claim 11, comprising a step of applying and curing the ultraviolet curable resin composition according to any one of claims 1 to 9 to a terminal portion of a substrate on which an electronic component is disposed.

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