Photocurable composition

Abstract

Provided is a photocurable composition that undergoes curing even at locations where light is blocked, does not readily experience superficial curing defects caused by oxidative damage, and undergoes sufficient curing from the surface to deep within. A photocurable composition according to the present invention includes a monomer (A) that has an ethylenically unsaturated double bond, a photobase generator (B), a thermal polymerization initiator (C), a chain transfer agent (D), and a filler (E).

Description

photocurable composition

[0001] The present invention relates to a photocurable composition, and more specifically to a photocurable composition that can be used as a reinforcing material for reinforcing the connection between a substrate and a component (or element) mounted on the substrate, and an electronic component device including a substrate and a component connected by the cured product of the photocurable composition.

[0002] Electronic component devices generally have a substrate and components (or elements) mounted on the substrate. To reinforce the connection between the substrate and the components, a resin composition is filled or applied to the gap between the substrate and the components. Methods for filling or applying the resin composition to the gap between the substrate and the components include underfill and sidefill methods.

[0003] In the underfill method, a resin composition is infiltrated into the entire gap between the substrate and the component, and the resin composition is cured to seal the entire gap between the substrate and the component, thereby reinforcing the connection between the substrate and the component.

[0004] In the side-fill method, a resin composition is applied only to a portion between the substrate and the component, for example, the periphery of the component, and then cured to seal the gap between the substrate and the component, reinforcing the connection between the substrate and the component. In the side-fill method, if a defective product is discovered, the component can be more easily removed from the substrate, i.e., the repairability is superior, but the reliability of the semiconductor device (such as heat resistance reliability) tends to be lower. To improve heat resistance and heat resistance reliability, it is preferable that the cured product has a high Tg and a small coefficient of thermal expansion (CTE).

[0005] Patent Document 1 discloses that a resin composition for side fill material contains, per 100 parts by mass of the resin composition, 23.0 to 67.0 parts by mass of an epoxy resin and an oxetane resin, 0.2 to 2.0 parts by mass of a photopolymerization initiator, 30.0 to 75.0 parts by mass of an inorganic filler, 1.0 part by mass of a thixotropy imparting agent, and may contain 0.5 parts by mass of a photosensitizer, and that upon photocuring, the composition has excellent thermal shock resistance and excellent repairability (

[0085] to

[0097] [Table 1] Examples 1 to 9). Patent Document 1 also discloses that the photocurable resin composition is excellent in both repairability and heat resistance reliability, but that thermosetting resin compositions are inferior in either repairability or heat resistance reliability.

[0006] In recent years, with the electrification of automobiles, components mounted on substrates have become larger due to their high functionality. Furthermore, the increase in high-current components has led to increased demands for heat resistance, insulation, and thermal shock reliability. Furthermore, with the advent of autonomous driving, the demand for heat resistance is increasing due to the increased pixel count of image sensors. Side-fill methods are attracting more attention because they require less resin composition and do not require penetration between the component and the substrate, allowing for shorter processing times. Furthermore, photocurable resins that can be cured at room temperature are attracting attention because they do not generate CO2 due to heating during the curing process of the resin composition.

[0007] WO2021 / 157472A1 Patent No. 7285486

[0008] To improve heat resistance and heat resistance reliability, photocurable compositions for side fills preferably have a high Tg and a low coefficient of thermal expansion of the cured product. To achieve this, the composition typically contains a large amount of filler. Patent Document 1 discloses a resin composition containing 30.0 to 75.0 parts by mass of filler per 100 parts by mass of the resin composition. This filler acts as an obstacle, attenuating light (UV) and preventing curing from progressing deep within the composition. There are also problems with the composition not curing in areas where light is blocked by components. Furthermore, typical radical polymerization can also cause the problem of poor curing of the composition surface due to oxygen hindrance.

[0009] Patent Document 2 discloses a photoreactive composition containing a vinyl monomer, a photobase generator, a thermal radical generator, and a filler, wherein the content of the photobase generator is 0.1 mol % or more and 1.0 mol % or less, relative to 100 mol % of the total vinyl monomers, the content of the thermal radical generator is 1 mol % or more and 5 mol % or less, relative to 100 mol % of the total vinyl monomers, the content of the filler is 10 parts by weight or more and 80 parts by weight or less, relative to 100 parts by weight of the photoreactive composition, and the polymerization rate of the vinyl monomer is 90% or more as measured by a specific measurement method. The composition also discloses that the composition cures efficiently deep into the composition, even when producing a molded product that is poorly transparent to light (see [Claims],

[0008] , and

[0017] ). However, Patent Document 1 does not teach that the cured product of the composition has a high Tg and a small thermal expansion coefficient, or that poor curing of the composition surface due to oxygen damage can be suppressed. Furthermore, Patent Document 1 exemplifies applications of the composition, such as films, hard coats for molded products, and resist materials, but does not teach the connection of a substrate and a component by side filling.

[0010] As a result of extensive research, the present inventors have found that a photocurable composition containing a monomer (A) having an ethylenically unsaturated double bond, a photobase generator (B), a thermal polymerization initiator (C), a chain transfer agent (D), and a filler (E) can solve the above-mentioned problems. Furthermore, they have found that such a photocurable composition is suitable for side fill applications, leading to the completion of the present invention.

[0011] That is, the present specification includes the following embodiments. 1. A photocurable composition comprising a monomer (A) having an ethylenically unsaturated double bond, a photobase generator (B), a thermal polymerization initiator (C), a chain transfer agent (D), and a filler (E). 2. The photocurable composition according to the above item 1, wherein the monomer (A) having an ethylenically unsaturated double bond comprises at least a monomer (A1) having a monofunctional ethylenically unsaturated double bond. 3. The photocurable composition according to the above item 2, wherein (A1) comprises a monomer having a monofunctional ethylenically unsaturated double bond and a nitrogen-containing structure. 4. The photocurable composition according to any one of the above items 1 to 3, wherein the monomer (A) having an ethylenically unsaturated double bond comprises a monomer (A2) having a polyfunctional ethylenically unsaturated double bond. 5. The photocurable composition according to the above item 4, wherein the monomer (A2) having a polyfunctional ethylenically unsaturated double bond comprises a monomer having an ethylenically unsaturated double bond with a functionality of 3 or more. 6. The photocurable composition according to any one of the above items 1 to 5, wherein the monomer (A) having an ethylenically unsaturated double bond contains 50% by mass or more of a monomer having an ethylenically unsaturated double bond whose homopolymer Tg is 100°C or higher. 7. The photocurable composition according to any one of the above items 1 to 6, wherein the chain transfer agent (D) contains a compound having at least one thiol group. 8. The photocurable composition according to any one of the above items 1 to 7, wherein the thermal polymerization initiator (C) contains a peroxide having a 10-hour half-life temperature of 70°C or higher. 9. The photocurable composition according to any one of the above items 1 to 8, wherein the content of the filler (E) is 60 to 86% by mass of the total amount of the photocurable composition. 10. The photocurable composition according to any one of the above items 1 to 9, wherein the photobase generator (B) is contained in an amount of 0.01 to 3 parts by mass per 100 parts by mass of the monomer (A) having an ethylenically unsaturated double bond.

[0012] The photocurable composition of the present invention can cure deep into the composition, even in areas where light is blocked by a member, and the cured product has a high Tg and a small thermal expansion coefficient, resulting in excellent heat resistance and heat resistance reliability, and can suppress poor curing of the composition surface due to oxygen damage. Therefore, the photocurable composition of the present invention can suppress poor reliability of electronic component devices due to side fill.

[0013] The photocurable composition according to an embodiment of the present invention comprises a monomer (A) having an ethylenically unsaturated double bond, a photobase generator (B), a thermal polymerization initiator (C), a chain transfer agent (D), and a filler (E). In this specification, the monomer (A) having an ethylenically unsaturated double bond (hereinafter also referred to as "(A) monomer") is a polymerizable monomer containing an ethylenically unsaturated double bond, and is not particularly limited as long as it can produce a photocurable composition intended by the present invention. The monomer (A) having an ethylenically unsaturated double bond preferably comprises a monomer (A1) having a monofunctional ethylenically unsaturated double bond (hereinafter also referred to as "(A1) monomer"), and / or a monomer (A2) having a polyfunctional ethylenically unsaturated double bond (hereinafter also referred to as "(A2) monomer").

[0014] In this specification, the term "monomer (A1) having a monofunctional ethylenically unsaturated double bond" refers to a polymerizable monomer containing one ethylenically unsaturated double bond, and is not particularly limited as long as it can produce the photocurable composition of the present invention. The term "monomer (A1) having a monofunctional ethylenically unsaturated double bond" refers to a monomer having a monofunctional (meth)acryloyl group (CH2=C(R)-, where R=H or CH3). Examples of monomers having a monofunctional (meth)acryloyl group include (meth)acrylic acid, methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, isoamyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, ethoxydiethylene glycol (meth)acrylate, 2-ethylhexyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, isobornyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, methoxytriethylene glycol (meth)acrylate, 2-ethylhexyl diglycol (meth)acrylate, methoxytetraethylene glycol (meth)acrylate, Examples of the monofunctional (meth)acrylic acid and its esters include acrylate, methoxypolyethylene glycol (meth)acrylate, benzyl (meth)acrylate, phenoxyethyl (meth)acrylate, phenoxydiethylene glycol (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, neopentyl glycol-(meth)acrylic acid-benzoic acid ester, glycidyl (meth)acrylate, 3,4-epoxycyclohexylmethyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, dicyclopentanyl (meth)acrylate, and 4-tert-butylcyclohexyl (meth)acrylate. Further, examples of the monomer (A1) having a monofunctional ethylenically unsaturated double bond include, in addition to the above-mentioned monomers having a monofunctional (meth)acroyl group, chlorine-containing monomers having a monofunctional ethylenically unsaturated double bond such as vinyl chloride and vinylidene chloride, monofunctional vinyl esters and vinyl ethers such as vinyl acetate and methyl vinyl ether, and monofunctional aromatic vinyl monomers such as styrene and α-methylstyrene.The monomers (A1) having a monofunctional ethylenically unsaturated double bond can be used alone or in combination.

[0015] Furthermore, as the monomer (A1) having a monofunctional ethylenically unsaturated double bond, a monomer having a nitrogen-containing structure and a monofunctional ethylenically unsaturated double bond can be exemplified, and it is preferable to include such a monomer. The nitrogen-containing structure means a chemical structure containing a nitrogen atom, and is not particularly limited as long as the photocurable composition intended by the present invention can be obtained. Examples of the monomer having a monofunctional ethylenically unsaturated double bond and a nitrogen-containing structure include (meth)acryloylmorpholine, N-vinyl-2-pyrrolidone, vinylpyridine, N-vinylcarbazole, pentamethylpiperidyl (meth)acrylate, tetramethylpiperidyl (meth)acrylate, etc., maleimides having a five-membered ring structure in which maleic acid is imidized, N-methylmaleimide, N-ethylmaleimide, N-butylmaleimide, 2-maleimidoacetic acid, 2-maleimidopropionic acid, N-phenylmaleimide, N-cyclohexylmaleimide, N-tert-butylmaleimide, and N-dodecyl Examples include monomers having a monofunctional ethylenically unsaturated double bond with a ring structure containing a nitrogen atom, such as maleimide, 4-maleimidophenol, N-benzylmaleimide, and 2,6-xylemaleimide; and monomers having a monofunctional ethylenically unsaturated double bond with a chain structure containing a nitrogen atom, such as (meth)acrylamide, N,N-dimethylacrylamide, N,N-diethylacrylamide, isopropylacrylamide, hydroxyethylacrylamide, diacetoneacrylamide, N-[3-(dimethylamino)propyl]acrylamide, N-isopropylacrylamide, and acrylonitrile.

[0016] When the monomer (A1) having a monofunctional ethylenically unsaturated double bond has a nitrogen-containing structure, the polymerization reaction of the photocurable composition can proceed more efficiently. These monomers having an ethylenically unsaturated double bond with a nitrogen-containing structure can be used alone or in combination. In order to more efficiently cure deep into the cured product obtained by light irradiation, the monomer (A1) having a monofunctional ethylenically unsaturated double bond preferably contains a monomer having a monofunctional ethylenically unsaturated double bond with a ring structure containing a nitrogen atom, and preferably contains (meth)acryloylmorpholine. Note that "(meth)acryloyl" means "acryloyl" or "methacryloyl".

[0017] In this specification, the polyfunctional ethylenically unsaturated double bond-containing monomer (A2) is a polymerizable monomer that contains two or more ethylenically unsaturated double bonds, and is not particularly limited as long as it can produce the photocurable composition of the present invention. Examples of the monomer (A2) having a polyfunctional ethylenically unsaturated double bond include aliphatic compounds having two ethylenically unsaturated double bonds, such as butadiene and isoprene; aromatic compounds having two vinyl groups, such as divinylbenzene; triethylene glycol diacrylate, 1,6-hexanediol di(meth)acrylate, PEG 200 di(meth)acrylate, PEG 400 di(meth)acrylate, PEG 600 di(meth)acrylate, dimethylol-tricyclodecane di(meth)acrylate, polytetramethylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, trimethylolpropane ethoxy tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and the like. Examples of the di(meth)acrylate include bisphenol A di(meth)acrylates, ditrimethylolpropane tetra(meth)acrylate, glycerin di(meth)acrylate, 2-hydroxy-3-acryloyloxypropyl methacrylate, di(meth)acrylates of polyhydric phenols such as bisphenol A, hydrogenated di(meth)acrylates of polyhydric phenols and polyhydric heterophenols, di(meth)acrylates of tricyclodecane dimethanol, di(meth)acrylates of diols having a carbon ring such as cyclohexyl diacrylate, and di- or higher functional (meth)acrylic acid esters such as alkylene oxide adducts of polyhydric phenols and polyhydric heterophenols, EO-modified di(meth)acrylates of benzenetriol, EO-modified tri(meth)acrylates of benzenetriol, isocyanuric acid EO-modified di(meth)acrylates, and isocyanuric acid EO-modified tri(meth)acrylates.

[0018] The polyfunctional ethylenically unsaturated double bond-containing monomer (A2) preferably includes a monomer having an ethylenically unsaturated double bond with three or more functional groups. When the (A2) monomer includes a monomer having an ethylenically unsaturated double bond with three or more functional groups, thermal reliability can be further improved. Examples of such polyfunctional (meth)acrylate monomers include branched and cyclic (meth)acrylates such as trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, ethylene oxide-modified trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, tetramethylolmethane triacrylate, tetramethylolmethane tetraacrylate, and tris(2-hydroxyethyl)isocyanurate triacrylate. The polyfunctional ethylenically unsaturated double bond-containing monomer (A2) can be used alone or in combination.

[0019] In this specification, "(meth)acrylic acid" refers to "acrylic acid" or "methacrylic acid", and "(meth)acrylate" refers to "acrylate" or "methacrylate".

[0020] The photocurable composition of the present invention preferably contains 13 to 40 parts by mass, more preferably 14 to 30 parts by mass, even more preferably 15 to 25 parts by mass, and even more preferably 16 to 20 parts by mass of the monomer (A) having an ethylenically unsaturated double bond per 100 parts by mass of the photocurable composition of the present invention. When the photocurable composition of the present invention contains 13 to 40 parts by mass of the monomer (A) having an ethylenically unsaturated double bond per 100 parts by mass of the photocurable composition, the photocurable composition exhibits an excellent reduction in cure shrinkage.

[0021] The monomer (A) having an ethylenically unsaturated double bond preferably contains 50% by mass or more of a monomer having an ethylenically unsaturated double bond, the homopolymer of which has a Tg of 100°C or higher. In this case, the photocurable composition according to an embodiment of the present invention advantageously exhibits an improved glass transition temperature. The Tg of the homopolymer of the monomer having an ethylenically unsaturated double bond can be measured by a method known as thermomechanical analysis (TMA). The Tg of the homopolymer of the monomer having an ethylenically unsaturated double bond is, for example, as follows: Homopolymer of acryloyl morpholine: 145°C Homopolymer of isobornyl acrylate: 97°C Homopolymer of isobornyl methacrylate: 180°C Homopolymer of trimethylolpropane triacrylate: 62°C Homopolymer of neopentyl glycol diacrylate: 117°C Homopolymer of dimethylol-tricyclodecane diacrylate: 190°C

[0022] The monomer (A) having an ethylenically unsaturated double bond preferably contains a monomer having an ethylenically unsaturated double bond whose homopolymer Tg is 100° C. or higher, more preferably contains a monomer having an ethylenically unsaturated double bond whose homopolymer Tg is 110° C. or higher, even more preferably contains a monomer having an ethylenically unsaturated double bond whose homopolymer Tg is 120° C. or higher, even more preferably contains a monomer having an ethylenically unsaturated double bond whose homopolymer Tg is 130° C. or higher, and particularly preferably contains a monomer having an ethylenically unsaturated double bond whose homopolymer Tg is 140° C. or higher. The monomer (A) having an ethylenically unsaturated double bond preferably contains 50% by mass or more, more preferably 50 to 95% by mass, even more preferably 60 to 90% by mass, and particularly preferably 70 to 80% by mass, of a monomer having an ethylenically unsaturated double bond whose homopolymer Tg is 100° C. or higher.

[0023] In this specification, the photobase generator (B) refers to a substance that generates a base upon irradiation with light, and is not particularly limited as long as the photocurable composition of the present invention can be obtained. Examples of light include infrared light, visible light, ultraviolet light, and electron beams, with ultraviolet light and visible light being preferred.

[0024] Examples of the photobase generator (B) include oxime ester compounds, ammonium compounds, benzoin compounds, dimethoxybenzylurethane compounds, and orthonitrobenzylurethane compounds.

[0025] More specifically, examples of the photobase generator (B) include 2-(9-oxoxanthen-2-yl)propionic acid 1,5,7-triazabicyclo[4.4.0]dec-5-ene, 9-anthrylmethyl N,N-diethylcarbamate, (E)-1-[3-(2-hydroxyphenyl)-2-propenoyl]piperidine, guanidinium 2-(3-benzoylphenyl)propionate, 1-(anthraquinone-2-yl)ethyl imidazole carboxylate, 2-nitrophenylmethyl 4-methacryloyloxypiperidine-1-carboxylate, 1-(anthraquinone-2-yl)-ethyl N,N-dicyclo Examples of the tetrakis(3-fluorophenyl)borate include hexyl carbamate, dicyclohexylammonium 2-(3-benzoylphenyl)propionate, cyclohexylammonium 2-(3-benzoylphenyl)propionate, 9-anthrylmethyl N,N-dicyclohexylcarbamate, 1,2-diisopropyl-3-[bis(dimethylamino)methylene]guanidium 2-(3-benzoylphenyl)propionate, 1,6-hexamethylene-bis(4,5-dimethoxy-2-nitrobenzylcarbamate), (Z)-{[bis(dimethylamino)methylidene]amino}-N-cyclohexyl(cyclohexylamino)methaniminium tetrakis(3-fluorophenyl)borate, etc. These can be used alone or in combination.

[0026] The content of the photobase generator (B) is not particularly limited, but is preferably 0.01 to 3.0 parts by mass, more preferably 0.02 to 2.0 parts by mass, even more preferably 0.05 to 1.5 parts by mass, even more preferably 0.1 to 1.0 part by mass, and particularly preferably 0.3 to 0.8 parts by mass, per 100 parts by mass of the total of the monomers (A) having an ethylenically unsaturated double bond. When the content of the photobase generator is 0.01 to 3.0 parts by mass, a more sufficient amount of base is generated, the concentration of the base component is further increased, and the cured product obtained by light irradiation can be cured more efficiently to the depths thereof.

[0027] In this specification, the thermal polymerization initiator (C) is a compound capable of initiating polymerization by heating, and is not particularly limited as long as the composition intended by the present invention can be obtained. The thermal polymerization initiator (C) preferably includes, for example, a thermal polymerization initiator having a 10-hour half-life temperature of 70°C or higher. The thermal polymerization initiator (C) may include, for example, an organic peroxide or an azo compound.

[0028] Examples of organic peroxides include benzoyl peroxide, diisopropyl peroxycarbonate, dioctyl peroxydicarbonate, t-butyl peroxylaurate, lauroyl peroxide, dioctanoyl peroxide, t-butyl peroxybenzoate, t-butylperoxy-2-ethylhexanoate, hydrogen peroxyperoxide, acetyl peroxide, cumyl peroxide, t-butyl peroxide, propionyl peroxide, benzoyl peroxide, chlorobenzoyl peroxide, dichlorobenzoyl peroxide, and bromomethyl peroxide. Examples of the perfluoroalkyl peroxide include benzoyl peroxide, lauroyl peroxide, ammonium persulfate, sodium persulfate, potassium persulfate, diisopropyl peroxycarbonate, tetralin hydroperoxide, 1-phenyl-2-methylpropyl-1-hydroperoxide, t-butyl pertriphenylacetate hydroperoxide, t-butyl performate, t-butyl peracetate, t-butyl perbenzoate, t-butyl perphenylacetate, t-butyl permethoxyacetate, t-butyl per-N-(3-toluyl)carbamate, ammonium bisulfate, sodium bisulfate, etc. These may be used alone or in combination.

[0029] Examples of the azo compound include azobisisobutyronitrile, azobis(2,4-dimethylvaleronitrile), 1,1-azobis(cyclohexane-1-carbonitrile), dimethyl 2,2-azobis(2-methylpropionate), 2,2'-azobis(2-amidinopropane), 2,2'-azobis(N,N'-dimethyleneisobutylamidine), 2,2'-azobis[2-(5-methyl-2-imidazolin-2-yl)propane], 1,1'-azobis(1-amidino-1-cyclohexane). Examples thereof include 2,2'-azobis(2-amidino-4-methylpentane), 2,2'-azobis(2-N-phenylaminoamidinopropane), 2,2'-azobis(1-imino-1-ethylamino-2-methylpropane), 2,2'-azobis(1-allylamino-1-imino-2-methylbutane), 2,2'-azobis(2-N-cyclohexylamidinopropane), 2,2'-azobis(2-N-benzylamidinopropane), and their hydrochloric acid, sulfuric acid, and acetate salts. These may be used alone or in combination of two or more.

[0030] The content of the thermal polymerization initiator (C) is not particularly limited, but is preferably 0.01 to 3.0 parts by mass, more preferably 0.02 to 2.0 parts by mass, even more preferably 0.05 to 1.5 parts by mass, even more preferably 0.1 to 1.0 part by mass, and particularly preferably 0.03 to 0.08 parts by mass, per 100 parts by mass of the total of the monomers (A) having an ethylenically unsaturated double bond. When the content of the thermal polymerization initiator (C) is within the above range, a more sufficient amount of radical active species is generated, the concentration of the radical active species is further increased, and the cured product can be cured more efficiently to a depth.

[0031] In this specification, the chain transfer agent (D) is not particularly limited as long as it is a compound that can continuously progress polymerization and improve reaction efficiency by allowing the chain transfer agent, which has received a radical, to react with a monomer again during a radical termination reaction or disproportionation reaction that occurs concomitantly with the progress of radical polymerization, and that can obtain the photocurable composition of the present invention. Examples of the chain transfer agent (D) include sulfur-free compounds such as disulfide compounds (dibenzothiazyl disulfide, etc.), sulfur compounds such as thiol compounds (2-mercaptobenzothiazole, trimethylolpropane tris(3-mercaptopropionate), and pentaerythritol tetrakis(3-mercaptobutyrate), styrene dimer derivatives (α-methylstyrene dimer, etc.), and aliphatic alcohols (stearyl alcohol, etc.). The chain transfer agent (D) preferably contains a compound having at least one thiol group. Examples of compounds having at least one thiol group include 2-mercaptobenzothiazole, trimethylolpropane tris(3-mercaptopropionate), and pentaerythritol tetrakis(3-mercaptobutyrate). The chain transfer agent (D) can be used alone or in combination.

[0032] The content of the chain transfer agent (D) is not particularly limited, but is preferably 0.1 to 15.0 parts by mass, more preferably 0.5 to 12.0 parts by mass, even more preferably 1.0 to 10.0 parts by mass, even more preferably 2.0 to 8.0 parts by mass, and particularly preferably 4.0 to 6.0 parts by mass, relative to 100 parts by mass of the total of the monomers having an ethylenically unsaturated double bond. When the content of the chain transfer agent (D) is within the above-mentioned range, the improvement in surface curability and deep section curability is excellent.

[0033] In this specification, the filler (E) is a substance that increases the amount of the photocurable composition according to an embodiment of the present invention and can impart a certain degree of strength to the cured product formed from the photocurable composition, and in some cases can contribute to viscosity adjustment or weight reduction. There are no particular limitations on the filler (E) as long as the photocurable composition intended by the present invention can be obtained.

[0034] Examples of fillers include calcium carbonate (heavy calcium carbonate, precipitated calcium carbonate, surface-treated calcium carbonate, etc.), magnesium carbonate, alkaline earth metal carbonates and sulfates such as barium sulfate, mica, graphite, talc, clay, glass flakes (glass beads), vermiculite, kaolinite, wollastonite (acicular calcium metasilicate), silica, diatomaceous earth, gypsum, cement, converter slag, shirasu, zeolite, cellulose powder, powdered rubber, zonolite, potassium titanate, bentonite, aluminum nitride, silicon nitride, zinc oxide, titanium oxide, alumina, zinc oxide, iron oxide, magnesium oxide, titanium oxide, magnesium hydroxide, hydroxide Examples of fillers include aluminum oxide, calcium silicate, calcium carbonate whiskers (needle-shaped calcium carbonate), ceramic short fibers or whiskers thereof, rock wool short fibers, glass fiber short fibers, potassium titanate short fibers, calcium silicate short fibers, aluminum silicate, carbon fiber short fibers, aramid fiber short fibers, mineral fibers such as sepiolite, various whiskers, and other fibrous fillers; hollow fillers such as glass balloons, silica balloons, resin balloons, and inorganic carbon hollow spheres; organic hollow fillers such as plastic balloons made of organic synthetic resins such as vinylidene chloride and acrylonitrile; and metallic fillers such as aluminum filler.

[0035] The photocurable composition preferably contains 60 to 86 parts by mass of filler (E), more preferably 65 to 84 parts by mass, even more preferably 70 to 83 parts by mass, and even more preferably 75 to 81 parts by mass of filler (E) relative to 100 parts by mass of the photocurable composition. When the photocurable composition contains 60 to 86 parts by mass of filler (E), the curing shrinkage rate and the linear expansion coefficient are further reduced.

[0036] The photocurable composition according to the embodiment of the present invention may appropriately contain an additive (F). Examples of the additive (F) include a plasticizer, a diluent, a surfactant, and other additives.

[0037] In an embodiment of the present invention, the plasticizer can increase plasticity and soften the composition, and is not particularly limited as long as it can obtain the photocurable composition of the present invention. Examples of the plasticizer include alkylbenzyl phthalate, dimethylcyclohexyl phthalate, phthalic acid polyester, benzoic acid ester, dialkyl phthalate, dialkylcyclohexane dicarboxylate, and trimellitic acid triester.

[0038] In the embodiment of the present invention, the diluent is not particularly limited as long as it can impart fluidity to the photocurable composition of the embodiment of the present invention and can obtain the photocurable composition intended by the present invention. Examples of the diluent include hydrocarbon solvents such as alcohol-based solvents, ketone-based solvents, paraffin-based solvents, isoparaffin-based solvents, naphthenic solvents, and aromatic solvents.

[0039] In an embodiment of the present invention, examples of other additives include moisture absorbents (calcium oxide, molecular sieves, etc.), thixotropic agents (organic bentonite, fumed silica, aluminum stearate, metallic soaps, castor oil derivatives, etc.), stabilizers [2,6-di-t-butyl-4-methylphenol, 2,2-methylene-bis(4-methyl-6-t-butylphenol), nickel dibutyldithiocarbamate, etc.], coupling agents such as silane or titanium, foaming agents, photoradical polymerization initiators, etc. The other additives are not particularly limited and can be used appropriately as long as the photocurable composition intended by the present invention can be obtained.

[0040] The photocurable composition according to an embodiment of the present invention can be produced by appropriately heating and mixing the above-described components. The device and method for mixing the above-described components are not particularly limited as long as the photocurable composition of the present invention can be produced. Specific examples of such mixing devices that can be used include a twin-screw mixer, planetary mixer, sigma mixer, kneader, attritor, grain mill, roll, dissolver, and the like. It is more preferable to use a twin-screw mixer, planetary mixer, or sigma mixer for mixing. Using a twin-screw mixer, planetary mixer, or sigma mixer allows for more efficient dispersion of high-viscosity materials. Furthermore, mixing can be carried out using a container capable of mixing, such as a tank or container.

[0041] The photocurable composition according to the embodiment of the present invention preferably has excellent viscosity, deep curability and surface curability (reaction rate of ethylenically unsaturated double bonds measured by FT-IR), coefficient of linear expansion and glass transition temperature (measured by TMA), and cure shrinkage. Detailed evaluation methods are described in the examples.

[0042] The photocurable composition according to an embodiment of the present invention can be applied to a desired location in any thickness and in any coating form using a known coating method, such as bead coating, slit coating, spray coating, swirl coating, or shot coating, and can be cured by irradiating it with light.

[0043] The photocurable composition of the present invention can be used as a reinforcing material for reinforcing the connection between a substrate and a component (or element) mounted on the substrate, and an electronic component device can be provided that includes a substrate and a component connected by a cured product of the photocurable composition. The electronic component device can be used in a wide range of fields, including electronics, electricity, automobiles, ships, aviation, housing, and medicine. The photocurable composition of the present invention can be efficiently cured from the surface to a deep portion of the cured product by irradiation with light. The photocurable composition of the present invention can be cured even in cases where light is blocked, for example, when a mold shaped to produce a light-blocked portion is used and the photocurable composition is injected into the mold to cause a reaction, or when the composition is used as a side fill material.

[0044] The present invention will be specifically and in detail explained below with reference to Examples and Comparative Examples, but these Examples are merely one embodiment of the present invention, and the present invention is not limited by these Examples. In the description of the Examples, unless otherwise specified, parts by weight and % by weight are based on the parts not taking into account the solvent.

[0045] The components used in this example are as follows: (A) Monomers (a1-1) Acryloylmorpholine (ACMO (trade name) manufactured by KJ Chemicals, homopolymer Tg = 145°C) (a1-2) Isobornyl acrylate (IBXA (trade name) manufactured by Osaka Organic Chemical Industry, Ltd., homopolymer Tg = 97°C) (a2-1) Trimethylolpropane triacrylate (TMPTA (trade name) manufactured by Daicel Allnex Corporation, homopolymer Tg = 62°C) (a2-2) Dimethylol-tricyclodecane diacrylate (IRR 214-K (trade name) manufactured by Daicel Allnex Corporation, homopolymer Tg = 190°C) (a2-3) Isocyanuric acid EO-modified di- and triacrylate (M-313 (trade name) manufactured by Toagosei Co., Ltd., homopolymer Tg > 250°C, diacrylate ratio: 30-40%)

[0046] (B) Photobase Generator (b1) (Z)-{[Bis(dimethylamino)methylidene]amino}-N-cyclohexyl(cyclohexylamino)methaniminium tetrakis(3-fluorophenyl)borate (WPBG-345 (trade name) manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) (b2) 1,2-Diisopropyl-3-[Bis(dimethylamino)methylene]guanidium 2-(3-benzoylphenyl)propionate (WPBG-266 (trade name) manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)

[0047] (C) Thermal polymerization initiator (c1) t-Butyl peroxy-2-ethylhexanoate (Perbutyl O (trade name) manufactured by NOF Corporation, 10-hour half-life is 72.1°C) (c2) t-Butyl peroxybenzoate (Perbutyl Z (trade name) manufactured by NOF Corporation, 10-hour half-life is 104.3°C) (D) Chain transfer agent (d1) Pentaerythritol tetrakis(3-mercaptobutyrate) (Karenz MT PE1 (trade name) manufactured by Resonac Corporation) (d2) α-methylstyrene dimer (manufactured by Mitsui Fine Chemicals, Inc.)

[0048] (E) Filler (e1) Amorphous silica (SC70-2 (trade name) manufactured by Nippon Steel Chemical & Material Co., Ltd., average particle size D50 = 10 μm) (F) Others (f1) 3-methacryloxypropyltrimethoxysilane (KBM-503 (trade name) manufactured by Shin-Etsu Chemical Co., Ltd.) (f2) 3-mercaptopropyltrimethoxysilane (KBM-803 (trade name) manufactured by Shin-Etsu Chemical Co., Ltd.) (G) Photoradical polymerization initiator (g1) 4,4'-bis(diethylamino)benzophenone (Omnirad 651 (trade name) manufactured by IGM Resins BV)

[0049] These components were blended in the proportions shown in Tables 1 and 2 to produce photocurable compositions of Examples 1 to 16 and Comparative Examples 1 to 3. In Comparative Example 2, a photoradical polymerization initiator (g1) different from the photobase generator was blended. For each of the above photocurable compositions, the viscosity, deep curability and surface curability (reaction rate of ethylenically unsaturated double bonds measured by FT-IR), linear expansion coefficient and glass transition temperature (measured by TMA), cure shrinkage and insulating properties were measured and evaluated using the methods described below. The results are shown in Tables 1 and 2.

[0050] Viscosity Measurement: Measured at 25° C. using a CP type viscometer in accordance with JIS Z8803. The viscosity is preferably 20 Pa·s or more.

[0051] Deep curability and surface curability were evaluated by measuring the reaction rate of the ethylenically unsaturated double bond using FT-IR. The photocurable composition was poured into a 1.7 cm diameter PP resin container to a height of 5 mm from the bottom. Next, the composition was irradiated from above with light at an illuminance of 1000 mW / m2 for 6 seconds using a UV-LED lamp with a center wavelength of 365 nm. One hour after irradiation, the cured product was cut to obtain a cross section, and the polymerization rate of the monomer having an ethylenically unsaturated double bond was measured at the irradiated surface and at a position 3 mm deep from the irradiated surface. The polymerization rate of the ethylenically unsaturated double bond monomer was measured by measuring the FT-IR spectrum before and after curing. The reaction rate was calculated based on the following formula using the peak area at 1410 cm-1 before and after curing, which is assigned to the in-plane bending vibration of the ethylenically unsaturated double bond, and the peak area of ​​the absorption spectrum of the carbonyl group (1740 cm-1), which remained unchanged before and after curing. FT-IR spectra were measured using an FT-IR measurement device "Nicolet IZ10" (manufactured by Thermo Fisher Scientific) at a measurement wavelength of 4000 to 400 cm-1 and 16 scans. Reaction rate (%) = 100 - [(peak area at 1410 cm-1 before and after curing) / (peak area at 1740 cm-1 after curing)] / [(peak area at 1410 cm-1 before curing) / (peak area at 1740 cm-1 before light irradiation)] ○: Reaction rate is 90% or more. △: Reaction rate is more than 85% but less than 90%. ×: Reaction rate is 85% or less.

[0052] Glass transition temperature / linear expansion coefficient: Measurements were made in accordance with JIS K7197. The photocurable composition was irradiated with a UV-LED lamp having a central wavelength of 365 nm at an illuminance of 1000 mW / m for 6 seconds to obtain a cured product. The cured product was cut into a size of 3 mm x 6 mm x 15 mm to obtain a sample. Using a thermomechanical analyzer (TMA) (a TMA7100 (trade name) manufactured by Hitachi High-Tech Science Corporation), the sample was heated from -40°C to 250°C at a rate of 5°C / min, the amount of thermal deformation was measured, and the linear expansion coefficient was calculated from the gradient of the line from 30°C to 80°C. The glass transition temperature (Tg) was calculated from the intersection of two tangents to the obtained TMA curve. Tg is preferably 95°C or higher, more preferably 130°C or higher. The linear expansion coefficient is preferably 28 ppm or lower, more preferably 20 ppm or lower.

[0053] Curing shrinkage was measured in accordance with JIS K5600 2-4. The specific gravity was measured before and after curing, and the curing shrinkage was calculated from the change in specific gravity. Curing shrinkage: r = [(ds - dl) / dl] x 100 Specific gravity of photocurable resin composition (liquid) before curing: dl Measured by pycnometer method. Specific gravity of cured product after curing: ds Measured by solid specific gravity measurement method (weighed in liquid). The curing shrinkage is preferably 6.5% or less, and more preferably 5% or less.

[0054] Insulation: A photocurable composition was applied to a JIS Type II comb-tooth substrate to a thickness of 200 μm. Then, a UV-LED lamp with a central wavelength of 365 nm was used to irradiate the substrate from above at an illuminance of 1000 mW / m2 for 6 seconds to prepare a test specimen. The insulation resistance of the test specimen after leaving it in an environment of 85°C and 85% RH for 24 hours was measured at a voltage of 100 V using an insulation resistor "R8340" (manufactured by Advantest Corporation). ◯: 1.0 x 109 Ω or more. △: Less than 1.0 x 109 Ω, 1.0 x 108 Ω or more. ×: Less than 1.0 x 108 Ω.

[0055]

[0056]

[0057]

[0058] The photocurable compositions of Examples 1 to 17 exhibited certain performance in terms of viscosity, deep curability and surface curability (reaction rate of ethylenically unsaturated double bonds measured by FT-IR), coefficient of linear expansion and glass transition temperature (measured by TMA), cure shrinkage and insulating properties, without any measurement error.

[0059] The photocurable compositions of Comparative Examples 1 to 3 were either x or unmeasurable with respect to any of viscosity, deep curability and surface curability (reaction rate of ethylenically unsaturated double bonds measured by FT-IR), linear expansion coefficient and glass transition temperature (measured by TMA), cure shrinkage rate and insulating property, and did not exhibit usable performance in any of these areas.

[0060] The photocurable composition of the present invention can cure deep into the composition, even in areas where light is blocked by a member, and the cured product has a high Tg and a small thermal expansion coefficient, resulting in excellent heat resistance and heat resistance reliability, and can suppress poor curing of the composition surface due to oxygen damage. Therefore, the photocurable composition of the present invention can suppress poor reliability of electronic component devices due to side fill.

Claims

1. A photocurable composition comprising a monomer having an ethylenically unsaturated double bond (A), a photobase generator (B), a thermal polymerization initiator (C), a chain transfer agent (D) and a filler (E).

2. The photocurable composition according to claim 1, wherein the monomer (A) having an ethylenically unsaturated double bond includes at least a monomer (A1) having a monofunctional ethylenically unsaturated double bond.

3. The photocurable composition according to claim 2, wherein (A1) comprises a monomer having a monofunctional ethylenically unsaturated double bond with a nitrogen-containing structure.

4. The photocurable composition according to claim 1, wherein the monomer (A) having an ethylenically unsaturated double bond includes a monomer (A2) having a polyfunctional ethylenically unsaturated double bond.

5. The photocurable composition according to claim 4, wherein the monomer (A2) having a polyfunctional ethylenically unsaturated double bond includes a monomer having an ethylenically unsaturated double bond with a functionality of 3 or more.

6. The photocurable composition according to claim 1, wherein the monomer (A) having an ethylenically unsaturated double bond contains 50% by mass or more of a monomer having an ethylenically unsaturated double bond whose homopolymer Tg is 100°C or higher.

7. The photocurable composition according to claim 1, wherein the chain transfer agent (D) comprises a compound having at least one thiol group.

8. The photocurable composition according to claim 1, wherein the thermal polymerization initiator (C) contains a peroxide having a 10-hour half-life temperature of 70°C or higher.

9. The photocurable composition according to claim 1, wherein the content of the filler (E) is 60 to 86 mass % of the total amount of the photocurable composition.

10. The photocurable composition according to claim 1, comprising 0.01 to 3 parts by mass of the photobase generator (B) per 100 parts by mass of the monomer (A) having an ethylenically unsaturated double bond.

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