JP7266484B2 - Sealant for electronic parts - Google Patents

Description

The present invention relates to a sealant for electronic parts. More particularly, it relates to a sealant for electronic parts containing a compound having a specific structure in its molecule. This sealant for electronic parts is highly sensitive to low-energy light and produces little outgas, so it is extremely useful as a sealant for electronic parts, and particularly useful as a sealant for display. be.

Photocurable resin compositions are widely used as sealants for electronic parts, such as display sealants, solar cell sealants, and semiconductor sealants. The display sealant includes, for example, a liquid crystal sealant, an organic EL display sealant, and a touch panel adhesive. What these materials have in common is that they are required to have excellent curability, little outgassing, and no damage to the display element.
However, a drawback of the photocurable resin composition is that the curing reaction does not proceed in areas where light cannot reach, and there are restrictions on the areas that can be used.

In particular, the liquid crystal sealant for the liquid crystal dropping method (hereinafter referred to as "sealant") is light-shielded by the wiring part of the array substrate of the liquid crystal display element and the black matrix part of the color filter substrate. The problem of defective display near the sealing portion has become more serious than before. That is, the presence of the light shielding portion makes the primary curing by the light insufficient, and a large amount of uncured components remain in the liquid crystal sealant. In this state, if the secondary curing process by heat is performed, the dissolution of the uncured component into the liquid crystal is accelerated by heat, which causes a problem of poor display in the vicinity of the seal portion.

In order to solve this problem, various studies have been made to improve the thermal reactivity. This is an attempt to suppress contamination of the liquid crystal by allowing the liquid crystal sealant, which has not been sufficiently cured by light, to quickly react at a low temperature in the light shielding portion. For example, Patent Documents 1 and 2 disclose a method using a thermal radical polymerization initiator. Further, Patent Documents 3 to 5 disclose a method using a polyvalent carboxylic acid as a curing accelerator.

However, in order for the thermal radical polymerization initiator to efficiently generate radicals, the molecular weight must be small to some extent. Liquid crystal contamination by the initiator itself becomes a problem.
Moreover, when a polycarboxylic acid is used, there is a possibility that the humidity resistance reliability may be impaired, and there are cases where it cannot be used depending on the application.

Recently, there is a movement to use visible light with a wavelength of 400 nm or more instead of ultraviolet light in the liquid crystal dropping method. Since visible light has lower energy than ultraviolet light, it is required that the liquid crystal sealant for the liquid crystal dripping method also cures with low energy. This is a subject similar to the improvement of curability in the light shielding portion.

As described above, although the development of liquid crystal sealants has been vigorously pursued, liquid crystal sealants with excellent photocurability and low liquid crystal contamination have not yet been realized. do not have.

JP-A-2004-126211 JP 2009-8754 A WO2007/138870 JP 2008-15155 A JP 2009-139922 A

The present invention relates to a sealant for electronic parts that is cured by irradiation with light such as ultraviolet light or visible light, and proposes a sealant for electronic parts that is highly sensitive to light and sufficiently cured even by low-energy light. be. The sealant for electronic parts has high curability in areas not sufficiently exposed to light, and has sufficient curability even with low-energy light irradiation in consideration of damage to other parts. It is useful as a deterrent.

As a result of intensive studies, the present inventors have found that a sealant for electronic components combined with a specific photopolymerization initiator has extremely excellent photocurability and sufficient curability even with low-energy light irradiation. This finding led to the present invention.
In this specification, "(meth)acryl" means "acryl and/or methacryl", and "(meth)acryloyl group" means "acryloyl group and/or methacryloyl group".

That is, the present invention relates to the following [1] to [16].
[1]
(A) A photopolymerization initiator having a phenyl sulfide structure and an oxime ester structure in the molecule, (B) a photopolymerization initiator having a thioxanthone structure in the molecule, (C) Encapsulation for electronic components containing a curable compound agent.
[2]
The sealant for electronic parts according to the preceding item [1], wherein the component (A) is a photopolymerization initiator having a furan structure, a phenyl sulfide structure and an oxime ester structure in the molecule.
[3]
The sealant for electronic parts according to the preceding item [1] or [2], wherein the component (A) is a compound represented by the following formula (A-1).

[4]
The sealant for electronic parts according to any one of the preceding items [1] to [3], wherein the component (B) is 2,4-diethylthioxanthone.
[5]
The sealant for electronic parts according to any one of the preceding items [1] to [4], wherein the component (C) is a (meth)acrylic compound.
[6]
The sealant for electronic parts according to any one of the preceding items [1] to [4], wherein the component (C) is a partial epoxy (meth)acrylate.
[7]
The sealant for electronic parts according to any one of the preceding items [1] to [6], further comprising (D) an organic filler.
[8]
The electronic component sealant according to the preceding item [7], wherein the component (D) is one or more organic fillers selected from the group consisting of urethane fine particles, acrylic fine particles, styrene fine particles, styrene olefin fine particles, and silicone fine particles. antidote.
[9]
The sealant for electronic parts according to any one of the preceding items [1] to [8], further comprising (E) an inorganic filler.
[10]
The sealant for electronic parts according to any one of the preceding items [1] to [9], further comprising (F) a silane coupling agent.
[11]
The sealant for electronic parts according to any one of the preceding items [1] to [10], further comprising (G) a thermosetting agent.
[12]
The sealant for electronic parts according to the preceding item [11], wherein the component (G) is an organic acid hydrazide compound.
[13]
The sealant for electronic parts according to any one of the preceding items [1] to [12], further comprising (H) a thermal radical polymerization initiator.
[14]
An electronic component using a cured product obtained by curing the sealant for electronic components according to [13] above.
[15]
The sealant for electronic parts according to any one of the preceding items [1] to [13], which is a sealant for a liquid crystal dropping method.
[16]
A liquid crystal display cell adhered using the sealant for liquid crystal dropping method according to the preceding item [15].

The sealant for electronic parts of the present invention exhibits sufficient curability even with low-energy light, and is excellent in moisture permeability and adhesiveness. It is very useful as a sealant for In addition, when used as a sealant for the liquid crystal dripping method, it is excellent in voltage holding ratio and liquid crystal orientation.

[(A) a photopolymerization initiator having an oxime ester structure in the molecule]
The electronic component sealant of the present invention contains a photopolymerization initiator having a phenyl sulfide structure and an oxime ester structure in the molecule (hereinafter also simply referred to as "component (A)"). Component (A) is very sensitive to low energy light. Therefore, it is suitable for use as a liquid crystal sealant because it can prevent the curable compound from eluting into the liquid crystal and adversely affect the display characteristics of the liquid crystal.

Component (A) has a phenylsulfide structure and an oxime structure in its molecule, and more preferably has a furan structure, a phenylsulfide structure and an oxime ester structure in its molecule. This is because a compound having both of these structures can cure the sealing agent for electronic parts even with weak visible light, and has good contamination property to the liquid crystal.
The furan structure may be a furan ring itself or a ring-condensed structure with other rings, including skeletons such as benzofuran and isobenzofuran. Those containing a benzofuran skeleton are preferred.
Further, the furan structure may have other substituents. Examples of substituents include C1-C10 alkyl groups, C1-C10 alkoxy groups, C1-C10 aryl groups, halogen atoms, hydroxy groups, carboxy groups, nitro groups, and cyano groups.
The C1-C10 alkyl group is preferably a C1-C6 alkyl group, and an alkyl group having a linear, branched or cyclic structure such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group and a hexyl group. is more preferred, and methyl group, ethyl group, butyl group and tert-butyl group are particularly preferred. The C1-C10 alkoxy group is preferably a C1-C6 alkoxy group, and more preferably an alkoxy group having a linear, branched or cyclic structure such as a methoxy group, an ethoxy group, a propoxy group, a butoxy group, and a methoxy group, an ethoxy Groups such as the propoxy group are particularly preferred. A phenyl group is preferred as the C1-C10 aryl group.
The furan structure is preferably bonded to a phenyl sulfide (diphenyl sulfide) structure, a diphenyl ether structure or a fluorene structure via a carbonyl group.

Examples of component (A) include IRGACURE OXE01, OXE02, OXE03 and OXE04 (manufactured by BASF), and OXE04 represented by the following formula (A-1) is particularly preferred.

Component (A) may be used alone or in combination of two or more. In the sealant for electronic parts of the present invention, the amount of component (A) compounded is usually 0.1 to 5 parts by mass, preferably 0.2 to 3 parts by mass, per 100 parts by mass of the curable compound. , more preferably 0.3 to 1.5 parts by mass, particularly preferably 0.3 to 1.0 parts by mass.

[(B) a photopolymerization initiator having a thioxanthone structure in the molecule]
The sealant for electronic parts of the present invention contains, as component (B), a photopolymerization initiator having a thioxanthone structure in its molecule (hereinafter also simply referred to as "component (B)").
The thioxanthone structure has a wide ultraviolet absorption range and is particularly useful for applications using weak light or visible light.

Examples of component (B) include 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, 2,4-diisopropylthioxanthone and the like.
Component (B) may be used alone or in combination of two or more. In the sealant for electronic parts of the present invention, the amount of component (B) compounded is usually 0.1 to 5 parts by mass, preferably 0.2 to 3 parts by mass, per 100 parts by mass of the curable compound. , more preferably 0.3 to 1.5 parts by mass, particularly preferably 0.5 to 1.5 parts by mass.

The sealant for electronic parts of the present invention exhibits high sensitivity to low-energy light by using both the component (A) and the component (B). Therefore, the cured product has good moisture permeability, and there is little decrease in adhesive strength even after the environmental test.

[(C) curable compound]
The resin composition of the present invention contains a curable compound (hereinafter also simply referred to as "component (C)") as component (C).
Component (C) is not particularly limited as long as it is a compound that is cured by light, heat, or the like, but epoxy compounds and (meth)acrylic compounds are preferred.

The epoxy compound is not particularly limited, but is preferably a bifunctional or higher epoxy compound. type epoxy resin, cresol novolak type epoxy resin, bisphenol A novolak type epoxy resin, bisphenol F novolak type epoxy resin, alicyclic epoxy resin, aliphatic chain epoxy resin, glycidyl ester type epoxy resin, glycidylamine type epoxy resin, hydantoin type epoxy resin, isocyanurate type epoxy resin, phenol novolac type epoxy resin having a triphenolmethane skeleton, other diglycidyl etherified products of bifunctional phenols such as catechol and resorcinol, diglycidyl etherified products of bifunctional alcohols, and Examples thereof include halides and hydrogenated products thereof. Among these, bisphenol A type epoxy resin and resorcinol diglycidyl ether are preferable from the viewpoint of liquid crystal contamination.

(Meth)acrylic compounds include, for example, (meth)acrylic ester compounds and epoxy (meth)acrylate compounds.
Specific examples of (meth)acrylic ester compounds include N-acryloyloxyethylhexahydrophthalimide, acryloylmorpholine, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, cyclohexane-1,4-dimethanol mono (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, phenoxyethyl (meth) acrylate, phenyl polyethoxy (meth) acrylate, 2-hydroxy-3-phenyloxypropyl (meth) acrylate, o-phenylphenol monoethoxy ( meth) acrylate, o-phenylphenol polyethoxy (meth) acrylate, p-cumylphenoxyethyl (meth) acrylate, isobornyl (meth) acrylate, tribromophenyloxyethyl (meth) acrylate, dicyclopentanyl (meth) acrylate , dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate (meth)acrylate, tricyclodecanedimethanol di(meth)acrylate, bisphenol A polyethoxydi(meth)acrylate, bisphenol A polypropoxydi(meth)acrylate, bisphenol F polyethoxydi(meth)acrylate, ethylene glycol di(meth)acrylate, Polyethylene glycol di(meth)acrylate, tris(acryloxyethyl)isocyanurate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, dipentaerythritol penta(meth)acrylate, tripentaerythritol hexa(meth) acrylates, tripentaerythritol penta(meth)acrylate, trimethylolpropane tri(meth)acrylate, trimethylolpropane polyethoxytri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, neopentyl glycol and hydroxypivalic acid ester di(meth)acrylate Monomers such as acrylates and diacrylates of ε-caprolactone adducts of esters of neopentyl glycol and hydroxypivalic acid can be mentioned. N-acryloyloxyethylhexahydrophthalimide, phenoxyethyl (meth)acrylate, and dicyclopentenyloxyethyl (meth)acrylate are preferred.

An epoxy (meth)acrylate compound is obtained by a known method by reacting an epoxy compound with (meth)acrylic acid. The epoxy compound used as a raw material is not particularly limited, but is preferably a bifunctional or higher epoxy compound, such as resorcinol diglycidyl ether, bisphenol A type epoxy compound, bisphenol F type epoxy compound, bisphenol S type epoxy compound. , phenol novolac type epoxy compound, cresol novolak type epoxy compound, bisphenol A novolak type epoxy compound, bisphenol F novolak type epoxy compound, alicyclic epoxy compound, aliphatic chain epoxy compound, glycidyl ester type epoxy compound, glycidylamine type epoxy compounds, hydantoin-type epoxy compounds, isocyanurate-type epoxy compounds, phenolic novolac-type epoxy compounds having a triphenolmethane skeleton, other diglycidyl ethers of bifunctional phenols such as catechol and resorcinol, diglycidyl ethers of bifunctional alcohols compounds, and halides and hydrogenated products thereof. Among these, bisphenol A type epoxy compounds and resorcinol diglycidyl ether are preferable from the viewpoint of liquid crystal contamination.

Also, as the component (C), a partial epoxy (meth)acrylate in which a part of the epoxy group is acryl-esterified is preferably used. Partial epoxy (meth)acrylates are mixtures of acrylic and epoxy compounds.
The ratio of the epoxy group to the (meth)acryloyl group is not limited and can be adjusted appropriately, but the acrylation ratio is preferably about 30 to 70%.

Component (C) may be used alone or in combination of two or more. In the electronic component sealant of the present invention, the amount of component (C) to be blended is usually 20 to 95% by mass, preferably 50 to 90% by mass, based on the total amount of the electronic component sealant.

[(D) organic filler]
The sealant for electronic components of the present invention may contain an organic filler (hereinafter also simply referred to as "component (D)") as component (D). Examples of the organic filler include urethane fine particles, acrylic fine particles, styrene fine particles, styrene olefin fine particles and silicone fine particles. KMP-594, KMP-597, KMP-598 (manufactured by Shin-Etsu Chemical Co., Ltd.), Torayfil ^RTM E-5500, 9701 and EP-2001 (manufactured by Dow Corning Toray Co., Ltd.) are preferred as the fine silicone particles, and JB- 800T, HB-800BK (Neagari Kogyo Co., Ltd.), Lavalon ^RTM T320C, T331C, SJ4400, SJ5400, SJ6400, SJ4300C, SJ5300C, and SJ6300C (manufactured by Mitsubishi Chemical) are preferable as styrene fine particles, and Septon ^RTM SEPS2004, as styrene olefin fine particles. SEPS2063 is preferred.
These organic fillers may be used alone or in combination of two or more. Moreover, it is good also as a core shell structure using 2 or more types. Among these, acrylic fine particles and silicone fine particles are preferred.
When the acrylic fine particles are used, it is preferable that the acrylic rubber has a core-shell structure composed of two kinds of acrylic rubbers, and particularly preferably, the core layer is n-butyl acrylate and the shell layer is methyl methacrylate. This is marketed by Aica Kogyo Co., Ltd. as Zephiac ^RTM F-351.
Examples of the fine silicone particles include organopolysiloxane crosslinked powders and linear dimethylpolysiloxane crosslinked powders. Composite silicone rubbers include those obtained by coating the surface of the silicone rubber with a silicone resin (for example, polyorganosilsesquioxane resin). Among these fine particles, particularly preferred are silicone rubber particles of linear dimethylpolysiloxane crosslinked powder or composite silicone rubber particles of silicone resin-coated linear dimethylpolysiloxane crosslinked powder. These things may be used independently and may use 2 or more types together. Further, preferably, the shape of the rubber powder is spherical so that the increase in viscosity after addition is small. When component (D) is used in the electronic component sealant of the present invention, it is usually 5 to 50% by mass, preferably 5 to 30% by mass, based on the total amount of the electronic component sealant.

[(E) inorganic filler]
The sealant for electronic parts of the present invention may contain an inorganic filler (hereinafter also simply referred to as component (E)) as component (E). Inorganic fillers contained in the present invention include silica, silicon carbide, silicon nitride, boron nitride, calcium carbonate, magnesium carbonate, barium sulfate, calcium sulfate, mica, talc, clay, alumina, magnesium oxide, zirconium oxide, and aluminum hydroxide. , magnesium hydroxide, calcium silicate, aluminum silicate, lithium aluminum silicate, zirconium silicate, barium titanate, glass fiber, carbon fiber, molybdenum disulfide, asbestos, etc., preferably fused silica, crystalline silica, silicon nitride, nitride Examples include boron, calcium carbonate, barium sulfate, calcium sulfate, mica, talc, clay, alumina, aluminum hydroxide, calcium silicate, and aluminum silicate, preferably silica, alumina, and talc. These inorganic fillers may be used in combination of two or more.
If the average particle size of the inorganic filler is too large, it may cause defects such as failure to properly form a gap when the upper and lower glass substrates are bonded together when manufacturing a liquid crystal display cell with a narrow gap. 700 nm or less, more preferably 700 nm or less. A preferred lower limit is about 10 nm, more preferably about 100 nm. The particle size can be measured with a laser diffraction/scattering particle size distribution analyzer (dry type) (manufactured by Seishin Enterprise Co., Ltd.; LMS-30).
When an inorganic filler is used in the electronic component sealant of the present invention, it is usually 3 to 50% by mass, preferably 3 to 30% by mass, based on the total amount of the electronic component sealant. If the content of the inorganic filler is less than 3% by mass, the adhesion strength to the glass substrate is lowered, and the moisture resistance reliability is also inferior, so that the adhesion strength after moisture absorption may be greatly reduced. Moreover, when the content of the inorganic filler is more than 50% by mass, the content of the filler is too large, so that the liquid crystal cell may not be easily crushed and the gap formation of the liquid crystal cell may not be possible.

[(F) Silane coupling agent]
The sealant for electronic parts of the present invention can be improved in adhesive strength and moisture resistance by adding a silane coupling agent (hereinafter also simply referred to as "component (F)") as component (F). can.
Component (F) includes 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltri Methoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, N-(2-aminoethyl)3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)3-aminopropylmethyltrimethoxysilane, 3- aminopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, vinyltrimethoxysilane, N-(2-(vinylbenzylamino)ethyl)3-aminopropyltrimethoxysilane hydrochloride, 3-methacryloxypropyltrimethoxysilane, 3-chloropropylmethyldimethoxysilane, 3-chloropropyltrimethoxysilane and the like. These silane coupling agents are sold as KBM series, KBE series, etc. by Shin-Etsu Chemical Co., Ltd., etc., and are readily available on the market. When component (F) is used in the sealant for electronic parts of the present invention, it is preferably in an amount of 0.05 to 3% by mass based on the total amount of the sealant for electronic parts.

[(G) Thermosetting agent]
The sealant for electronic parts of the present invention may contain a thermosetting agent (hereinafter also simply referred to as "component (G)") as component (G). Component (G) reacts nucleophilically with a lone pair of electrons or anions in the molecule, and examples thereof include polyvalent amines, polyvalent phenols, and organic acid hydrazide compounds. However, it is not limited to these. Among these, organic acid hydrazide compounds are particularly preferably used. For example, the aromatic hydrazides terephthalic acid dihydrazide, isophthalic acid dihydrazide, 2,6-naphthoic acid dihydrazide, 2,6-pyridinedihydrazide, 1,2,4-benzenetrihydrazide, 1,4,5,8-naphthoic acid Tetrahydrazide, pyromellitic acid tetrahydrazide and the like can be mentioned. Examples of aliphatic hydrazide compounds include formhydrazide, acetohydrazide, propionic hydrazide, oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, glutaric acid dihydrazide, adipic acid dihydrazide, pimelic acid dihydrazide, sebacic acid dihydrazide, 1,4-cyclohexanedihydrazide, tartaric acid dihydrazide, malic acid dihydrazide, iminodiacetic acid dihydrazide, N,N'-hexamethylenebissemicarbazide, citric acid trihydrazide, nitriloacetic acid trihydrazide, cyclohexanetricarboxylic acid trihydrazide, 1,3-bis( a dihydrazide compound having a hydantoin skeleton such as hydrazinocarbonoethyl)-5-isopropylhydantoin, preferably a valine hydantoin skeleton (a skeleton in which a carbon atom of the hydantoin ring is substituted with an isopropyl group), tris(1-hydrazinocarbonylmethyl) isocyanurate, tris(2-hydrazinocarbonylethyl)isocyanurate, tris(1-hydrazinocarbonylethyl)isocyanurate, tris(3-hydrazinocarbonylpropyl)isocyanurate, bis(2-hydrazinocarbonylethyl)isocyanurate etc. can be given. From the balance between curing reactivity and latency, isophthalic acid dihydrazide, malonic acid dihydrazide, adipic acid dihydrazide, tris(1-hydrazinocarbonylmethyl)isocyanurate, tris(1-hydrazinocarbonylethyl)isocyanurate, tris( 2-hydrazinocarbonylethyl)isocyanurate, tris(3-hydrazinocarbonylpropyl)isocyanurate, particularly preferably tris(2-hydrazinocarbonylethyl)isocyanurate.
Component (G) may be used alone or in combination of two or more. When component (G) is used in the electronic component sealant of the present invention, it is usually 0.1 to 10% by mass, preferably 1 to 10% by mass, based on the total amount of the electronic component sealant.

[(H) Thermal radical polymerization initiator]
The sealant for electronic parts of the present invention may contain a thermal radical polymerization initiator (hereinafter also simply referred to as "component (H)") as component (H) to improve the curing speed and curability. can.
The thermal radical polymerization initiator is not particularly limited as long as it is a compound that generates radicals by heating and initiates a chain polymerization reaction, but organic peroxides, azo compounds, benzoin compounds, benzoin ether compounds, acetophenone compounds, benzopinacol, etc. benzopinacol is preferably used. For example, organic peroxides include Kayamec ^RTM A, M, R, L, LH, SP-30C, Perkadox CH-50L, BC-FF, Kadox B-40ES, Perkadox 14, Trigonox ^RTM 22-70E, 23-C70, 121, 121-50E, 121-LS50E, 21-LS50E, 42, 42LS, Kayaester ^RTM P-70, TMPO-70, CND-C70, OO-50E, AN, Kayabutyl ^RTM B, Parkadox 16 , Kayacarbon ^RTM BIC-75, AIC-75 (manufactured by Kayaku Akzo Co., Ltd.), Permek ^RTM N, H, S, F, D, G, Perhexa ^RTM H, HC, TMH, C, V, 22, MC, Percure ^RTM AH, AL, HB, Perbutyl ^RTM H, C, ND, L, Permyl ^RTM H, D, Perroyl ^RTM IB, IPP, Perocta ^RTM ND (manufactured by NOF Corporation) and the like are commercially available.

As azo compounds, VA-044, 086, V-070, VPE-0201, VSP-1001 (manufactured by Wako Pure Chemical Industries, Ltd.) and the like are commercially available.

The content of component (H) is preferably 0.0001 to 10% by mass, more preferably 0.0005 to 5% by mass, based on the total amount of the sealant for electronic parts. 3% by weight is particularly preferred.

The sealant for electronic parts of the present invention may further contain, if necessary, photopolymerization initiators other than components (A) and (B), curing accelerators such as organic acids and imidazole, radical polymerization inhibitors, pigments, Additives such as leveling agents, antifoaming agents and solvents can be added.

[Photopolymerization initiator other than components (A) and (B)]
Photopolymerization initiators other than components (A) and (B) include, for example, benzyldimethylketal, 1-hydroxycyclohexylphenylketone, diethylthioxanthone, benzophenone, 2-ethylanthraquinone, 2-hydroxy-2-methylpropio phenone, 2-methyl-[4-(methylthio)phenyl]-2-morpholino-1-propane, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, camphorquinone, 9-fluorenone, diphenyl disulfide, etc. be able to. Specifically, IRGACURE ^RTM 651, 184, 2959, 127, 907, 369, 379EG, 819, 784, 754, 500, DAROCURE ^RTM 1173, LUCIRIN ^RTM TPO (all manufactured by BASF), Seikuol ^RTM Z, BZ, BEE, BIP, BBI (all manufactured by Seiko Kagaku Co., Ltd.) and the like can be mentioned.
Also, from the viewpoint of liquid crystal contamination, it is preferable to use those having a (meth)acrylic group in the molecule, for example, 2-methacryloyloxyethyl isocyanate and 1-[4-(2-hydroxyethoxy)-phenyl]- Reaction products with 2-hydroxy-2-methyl-1-propan-1-one are preferably used. This compound can be produced and obtained by the method described in International Publication No. 2006/027982.
In the resin composition of the present invention, when using a photopolymerization initiator other than components (A) and (B), it is usually 0.001 to 3% by mass, preferably 0.001 to 3% by mass, based on component (C). 002 to 2% by mass.

[Curing accelerator]
Examples of curing accelerators include organic acids and imidazole.
Examples of the organic acid include organic carboxylic acid and organic phosphoric acid, and organic carboxylic acid is preferable. Specifically, aromatic carboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, benzophenonetetracarboxylic acid, furandicarboxylic acid, succinic acid, adipic acid, dodecanedioic acid, sebacic acid, thiodipropionic acid , cyclohexanedicarboxylic acid, tris(2-carboxymethyl)isocyanurate, tris(2-carboxyethyl)isocyanurate, tris(2-carboxypropyl)isocyanurate, bis(2-carboxyethyl)isocyanurate and the like. .
Further, as imidazole compounds, 2-methylimidazole, 2-phenylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-phenylimidazole, 1-benzyl -2-methylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole, 2,4-diamino-6 (2'-methylimidazole (1' )) Ethyl-s-triazine, 2,4-diamino-6(2′-undecylimidazole (1′)) ethyl-s-triazine, 2,4-diamino-6(2′-ethyl-4-methylimidazole (1′)) ethyl-s-triazine, 2,4-diamino-6(2′-methylimidazole (1′)) ethyl-s-triazine isocyanuric acid adduct, 2-methylimidazole isocyanuric acid 2:3 adduct, 2-phenylimidazole isocyanuric acid adduct, 2-phenyl-3,5-dihydroxymethylimidazole, 2-phenyl-4-hydroxymethyl-5-methylimidazole, 1-cyanoethyl-2-phenyl-3,5- and dicyanoethoxymethylimidazole.
When a curing accelerator is used in the electronic component sealant of the present invention, it is usually 0.1 to 10% by mass, preferably 1 to 5% by mass, based on the total amount of the electronic component sealant.

[Radical polymerization inhibitor]
The radical polymerization inhibitor is not particularly limited as long as it is a compound that prevents polymerization by reacting with radicals generated from a photopolymerization initiator, a thermal radical polymerization initiator, or the like. Phenol-based, nitroso-based, etc. can be used. Specifically, naphthoquinone, 2-hydroxynaphthoquinone, 2-methylnaphthoquinone, 2-methoxynaphthoquinone, 2,2,6,6-tetramethylpiperidine-1-oxyl, 2,2,6,6-tetramethyl-4 - hydroxypiperidine-1-oxyl, 2,2,6,6-tetramethyl-4-methoxypiperidine-1-oxyl, 2,2,6,6-tetramethyl-4-phenoxypiperidine-1-oxyl, hydroquinone, 2-methylhydroquinone, 2-methoxyhydroquinone, parabenzoquinone, butylated hydroxyanisole, 2,6-di-t-butyl-4-ethylphenol, 2,6-di-t-butylcresol, stearyl β-(3, 5-di-t-butyl-4-hydroxyphenyl)propionate, 2,2'-methylenebis(4-ethyl-6-t-butylphenol), 4,4'-thiobis(3-methyl-6-t-butylphenol) , 4,4′-butylidenebis(3-methyl-6-t-butylphenol), 3,9-bis[1,1-dimethyl-2-[β-(3-t-butyl-4-hydroxy-5-methyl Phenyl)propionyloxy]ethyl]-2,4,8,10-tetraoxaspiro[5,5]undecane, pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] , 1,3,5-tris(3′,5′-di-t-butyl-4′-hydroxybenzyl)-sec-triazine-2,4,6-(1H,3H,5H)trione, para-methoxyphenol , 4-methoxy-1-naphthol, thiodiphenylamine, aluminum salt of N-nitrosophenylhydroxyamine, trade name ADEKA STAB LA-81, trade name ADEKA STAB LA-82 (manufactured by ADEKA CORPORATION) and the like, but are limited to these. not to be Among these, naphthoquinone-based, hydroquinone-based, nitroso-based, and piperidine-based radical polymerization inhibitors are preferred, and naphthoquinone, 2-hydroxynaphthoquinone, hydroquinone, 2,6-di-tert-butyl-p-cresol, Polystop 7300P (Hakuto Co., Ltd.) is more preferred, and Polystop 7300P (manufactured by Hakuto Co., Ltd.) is most preferred.
The content of the radical polymerization inhibitor is preferably 0.0001 to 1% by mass, more preferably 0.001 to 0.5% by mass, more preferably 0.01 to 0.5% by mass, based on the total amount of the sealant for electronic parts of the present invention. 2% by weight is particularly preferred.

As an example of the method for obtaining the sealant for electronic parts of the present invention, there is the following method. First, components (A) and (B) are heated and dissolved in component (C). Next, after cooling to room temperature, components (D), (E), (F), (G), (H), antifoaming agents, leveling agents, solvents, etc. are added as necessary, and a known mixing device, For example, the liquid crystal sealant of the present invention can be produced by uniformly mixing with a three-roll mill, sand mill, ball mill or the like and filtering through a metal mesh.

The sealant for electronic parts of the present invention is very useful as an adhesive for electronic parts. The adhesives for electronic parts include, but are not limited to, adhesives for flexible printed wiring boards, adhesives for TAB, adhesives for semiconductors, adhesives for various displays, and the like.

Moreover, the sealant for electronic parts of the present invention is very useful as a sealant for liquid crystal display cells, particularly as a sealant for liquid crystals. An example of a liquid crystal display cell in which the sealant for electronic parts of the present invention is used as a liquid crystal sealant is shown below.

A liquid crystal display cell manufactured using the liquid crystal sealing compound of the present invention comprises a pair of substrates having predetermined electrodes formed on the substrates, arranged facing each other at a predetermined interval, sealing the periphery with the liquid crystal sealing compound, and filling the gap with the liquid crystal sealing compound. A liquid crystal is enclosed. The type of liquid crystal to be enclosed is not particularly limited. Here, the substrate is composed of a combination of substrates, at least one of which is made of glass, quartz, plastic, silicon, or the like and has optical transparency. As a method for producing the liquid crystal sealing agent, after adding a spacer (gap control material) such as glass fiber to the liquid crystal sealing agent, the liquid crystal sealing agent is applied to one of the pair of substrates using a dispenser or a screen printing device. , Temporary curing is performed at 80 to 130° C., if necessary. After that, liquid crystal is dropped inside the weir of the liquid crystal sealant, and another glass substrate is overlapped in a vacuum to form a gap. After forming the gap, the liquid crystal display cell of the present invention can be obtained by curing at 90 to 130° C. for 30 minutes to 2 hours. When used as a photothermal combination type, the liquid crystal sealant portion is irradiated with ultraviolet rays by an ultraviolet irradiator for photocuring. The UV irradiation dose is preferably 500 to 6000 mJ/cm ² , more preferably 1000 to 4000 mJ/cm ² . After that, if necessary, the liquid crystal display cell of the present invention can be obtained by curing at 90 to 130° C. for 30 minutes to 2 hours. The thus-obtained liquid crystal display cell of the present invention is free from defective display due to liquid crystal contamination and is excellent in adhesiveness and humidity resistance reliability. Examples of spacers include glass fibers, silica beads, polymer beads, and the like. Although the diameter varies depending on the purpose, it is usually 2-8 μm, preferably 4-7 μm. The amount used is usually 0.1 to 4 parts by mass, preferably 0.5 to 2 parts by mass, and more preferably about 0.9 to 1.5 parts by mass based on 100 parts by mass of the liquid crystal sealing agent of the present invention. be.

The sealant for electronic parts of the present invention is very suitable for use as a sealant that needs to be cured with electronic parts designed to have a light-shielding portion or with low-energy light such as visible light. For example, they are a liquid crystal sealant, an organic EL sealant, and a touch panel adhesive that are used under the wiring light-shielding portion.

EXAMPLES The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the examples. Unless otherwise specified, "parts" and "%" in the text are based on mass.

[Examples 1 to 3, Reference Example 4 , Comparative Examples 1 to 6]
Components (A), (B), (C), (O-1), and (O-2) were mixed in the proportions shown in Table 1 below, and component (O-3) was heated and dissolved at 90°C. After cooling to room temperature, components (D), (E), (F), (G), (H), and (O-4) are added, stirred, and dispersed with a three-roll mill, It was filtered through a metal mesh (635 mesh) to prepare Examples 1 to 3, Reference Example 4 , and Comparative Examples 1 to 6 of sealing agents for electronic parts.

[Preparation of substrate with photo-alignment treatment type alignment film]
An alignment film solution (RN2880: manufactured by Nissan Chemical Industries, Ltd.) was spin-coated on a glass substrate, calcined on a 90° C. hot plate for 60 seconds, and baked in a 230° C. oven for 1 hour. Further, the alignment film-attached substrate was irradiated with ultraviolet rays of 3000 mJ/cm ² (measurement wavelength: 254 nm) using a UV irradiation machine.

[Preparation of liquid crystal cell for evaluation]
A light-shielding portion is provided in the frames of the main seal, the dummy seal, and the main seal so that the line width after bonding the sealant for electronic parts obtained on the substrate with the alignment film of the photo-alignment treatment type is 0.8 mm. A seal for evaluation was dispensed, and then a microdroplet of liquid crystal (JC-5015LA; manufactured by JNC Co., Ltd.) was dropped within the frame of the seal pattern. Furthermore, an in-plane spacer (Natoco spacer KSEB-525F; manufactured by Natoco Co., Ltd.; gap width after bonding: 5 μm) was dispersed on another substrate that had undergone rubbing, and was then thermally fixed. was attached to the substrate on which the liquid crystal had been dropped. After opening to the atmosphere and forming a gap, only the inside of the seal pattern frame was masked, and visible light (measurement wavelength: 405 nm) was irradiated with ultraviolet rays of 100 mJ/ ^cm2 or 3000 mJ/ ^cm2 using a UV irradiation machine, and then placed in an oven. It was heat-cured at 130° C. for 40 minutes to prepare a liquid crystal test cell for evaluation.

[Evaluation of liquid crystal alignment]
In the liquid crystal test cell for evaluation, the disordered liquid crystal alignment in the vicinity of the sealant for electronic parts was observed with a polarizing microscope and evaluated according to the criteria shown below. Table 1 shows the results.
⊚: No alignment disturbance of the liquid crystal was observed.
◯: Disordered alignment of liquid crystal is less than 0.2 mm from the sealant for electronic parts.
Δ: Orientation disorder of liquid crystal is 0.2 mm or more and less than 0.4 mm from the sealant for electronic parts.
x: A cell could not be formed because the alignment disturbance of the liquid crystal was 0.4 mm or more from the sealing agent for electronic parts, or the curing of the sealing agent for electronic parts was insufficient.

[Measurement of voltage holding ratio (VHR)]
An electrode was attached to the liquid crystal test cell for evaluation, and the voltage holding rate was measured under the conditions of an applied voltage of 5 V, a frequency of 1 Hz, and an atmosphere of 60° C. using a liquid crystal physical property measurement system (manufactured by Toyo Technica Co., Ltd.). Table 1 shows the results. A case in which a cell could not be formed due to insufficient curing of the sealant for electronic parts was evaluated as x.

[Moisture Permeability]
A 100 μm-thick thin film of a sealant for electronic parts sandwiched between polyethylene terephthalate (PET) films is irradiated with visible light of 3,000 mJ/cm ² using a UV irradiator. let me After curing, the PET film was peeled off to obtain a sample. The moisture permeability of the sample at 60° C. 90% was measured with a moisture permeability meter (L80-5000 manufactured by Lessy). Table 1 shows the results.

[Adhesion strength measurement]
1 g of glass fiber of 5 μm as a spacer is added to 100 g of sealant for electronic parts, and mixed and stirred. This sealant for electronic parts is applied on a 25 mm × 25 mm substrate with an alignment film by a dispenser or a screen printer, the substrate with a 25 mm × 30 mm alignment film is laminated, and a visible light of 3000 mJ / cm ² is applied with a UV irradiation machine. After irradiation with ultraviolet rays, it was placed in an oven and thermally cured at 130° C. for 40 minutes. Adhesion strength was measured by pressing the obtained test piece with a bond tester (SS-30WD: manufactured by Seishin Shoji Co., Ltd.) with a pin at a position 5 mm in a straight line from the edge of the sealant for electronic parts. Table 1 shows the results.

[Adhesive strength after PCT]
The sealant for electronic parts was applied to the alignment film-coated substrate, and the cured test piece was subjected to a PCT test (conditions: temperature 121 ° C., humidity 100%, atmospheric pressure 2 atm, test time 24 hours), and the adhesive strength was measured in the same manner. It was measured. Table 1 shows the results.

As shown in Table 1, the sealants for electronic parts of Examples 1 to 3 exhibited favorable properties in terms of voltage holding ratio, liquid crystal orientation, moisture permeability, and adhesiveness under low-energy radiation curing conditions. It was confirmed that the sealants for electronic parts of Examples 1 and 2 exhibited particularly good properties.

The sealant for electronic parts of the present invention has excellent voltage holding ratio, liquid crystal orientation, moisture permeability, and adhesiveness under low-energy ray curing conditions. Useful.

Claims (8)

(A) a photopolymerization initiator having a phenyl sulfide structure and an oxime ester structure in the molecule, (B) a photopolymerization initiator having a thioxanthone structure in the molecule, and (C) a liquid crystal dropping method seal containing a curable compound is an agent
The component (A) is a compound represented by the following formula (A-1),
The component (B) is 2,4-diethylthioxanthone,
A sealant for a liquid crystal dropping method, wherein the component (C) is a partial epoxy (meth)acrylate.

2. The sealant for liquid crystal dropping method according to claim 1 , further comprising (D) an organic filler. 3. The liquid crystal dropping method seal according to claim 2 , wherein the component (D) is one or more organic fillers selected from the group consisting of urethane fine particles, acrylic fine particles, styrene fine particles, styrene olefin fine particles, and silicone fine particles. agent. 4. The sealant for liquid crystal dropping method according to any one of claims 1 to 3 , further comprising (E) an inorganic filler. 5. The sealant for liquid crystal dropping method according to any one of claims 1 to 4 , further comprising (F) a silane coupling agent. 6. The sealant for liquid crystal dripping method according to any one of claims 1 to 5, further comprising (G) an organic acid hydrazide compound as a thermosetting agent. 7. The sealant for liquid crystal dropping method according to any one of claims 1 to 6 , further comprising (H) a thermal radical polymerization initiator. A liquid crystal display cell adhered using the sealant for a liquid crystal dropping method according to any one of claims 1 to 7 .