JP7332264B2 - Adhesive for electronic parts - Google Patents

Description

TECHNICAL FIELD The present invention relates to an adhesive for electronic parts, an electronic part, a liquid crystal sealant, and a liquid crystal display cell.

Electronic component adhesives are widely used as sealants for displays, sealants for solar cells, semiconductor sealants, and the like. The display sealant includes, for example, a liquid crystal display sealant, an organic EL display sealant, and a touch panel adhesive. These display sealants are required to have properties such as excellent curability, low outgassing, and no damage to display elements.

In recent years, in the field of displays, curved displays, highly flexible displays, and the like have been developed and commercialized. Substrates used in such displays are flexible, such as plastic films, instead of conventional rigid substrates such as glass (Patent Document 1). Against this background, the resin composition is being required to have the property of following the bending of the substrate or the like, that is, the property of being flexible even after curing.

On the other hand, in order to increase the flexibility of the cured product, it is an effective means to lower the crosslink density of the cured product. However, when the crosslink density is lowered, the moisture permeability is usually deteriorated. It is considered that this is due to the infiltration of moisture from loose portions of the network. Therefore, in order to ensure low moisture permeability, it is necessary to realize contradictory characteristics such as increasing flexibility without lowering the crosslink density, or lowering the crosslink density but not deteriorating the moisture permeability. .

Moreover, in recent years, tablet-type displays have become popular in educational settings, and there is a strong demand for durability against dropping of displays. Therefore, adhesives for electronic parts are required to have an adhesive strength that does not cause the display to peel off even if the display is dropped.

JP 2012-238005 A

The present invention proposes an adhesive for electronic parts that does not peel off due to impact when the electronic parts are dropped, and the electronic parts.

As a result of intensive studies, the inventors of the present invention have found that there is a certain relationship between the peeling of the adhesive due to the drop of the electronic component and the loss tangent tan δ, and have completed the present invention.
In this specification, "(meth)acrylate" means "acrylate" and/or "methacrylate".

That is, the present invention relates to the following [1] to [7].
[1]
(A) A curable compound and (B) a heat curing agent are contained, and the cured product has a loss tangent tan δ value of 0.1 or more when measured with a dynamic viscoelasticity measuring device at a frequency of 5 Hz, a tensile mode, and 25 ° C. Adhesive for electronic parts.
[2]
The adhesive for electronic parts according to the preceding item [1], wherein a cured product having a thickness of 300 μm has a moisture permeability of 60 g/m ² ·24 hours or less, measured according to JIS-K7129 in an environment of 60° C. and 90% RH.
[3]
The adhesive for electronic parts according to the preceding item [1] or [2], wherein the component (A) contains at least one selected from urethane (meth)acrylates and polybutadiene compounds.
[4]
The adhesive for electronic components according to any one of the preceding items [1] to [3], further comprising (C) a thermal radical polymerization initiator.
[5]
An electronic component bonded with a cured product obtained by curing the adhesive for electronic components according to any one of [1] to [4] above.
[6]
A liquid crystal sealant using the adhesive for electronic parts according to any one of the preceding items [1] to [4].
[7]
A liquid crystal display cell adhered using the liquid crystal sealant according to the preceding item [6].

INDUSTRIAL APPLICABILITY The present invention can provide an adhesive for electronic components that is excellent in impact resistance when electronic components are dropped.

[(A) curable compound]
The adhesive for electronic parts of the present invention contains a curable compound (hereinafter also simply referred to as "component (A)") as component (A).
Component (A) is not particularly limited as long as it is a compound that is cured by light, heat, or the like, but is preferably a compound having a (meth)acrylic group or an epoxy group, such as (meth)acrylate or epoxy (meth)acrylate. , urethane (meth)acrylates, epoxy resins, and polybutadiene compounds are more preferable, and it is particularly preferable to contain at least one selected from urethane (meth)acrylates and polybutadiene compounds.

[(Meth)acrylate]
Specific examples of (meth)acrylates 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, phenylpolyethoxy (meth)acrylate, 2-hydroxy-3-phenyloxypropyl (meth)acrylate, o-phenylphenol monoethoxy (meth)acrylate acrylates, o-phenylphenol polyethoxy (meth) acrylate, p-cumylphenoxyethyl (meth) acrylate, isobornyl (meth) acrylate, tribromophenyloxyethyl (meth) acrylate, dicyclopentanyl (meth) acrylate, di Cyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate ) acrylate, tricyclodecanedimethanol (meth) acrylate, bisphenol A polyethoxy di (meth) acrylate, bisphenol A polypropoxy di (meth) acrylate, bisphenol F polyethoxy di (meth) acrylate, ethylene glycol di (meth) acrylate, polyethylene glycol di (Meth)acrylates, tris(acryloxyethyl)isocyanurate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, dipentaerythritol penta(meth)acrylate, tripentaerythritol hexa(meth)acrylate, tri pentaerythritol penta(meth)acrylate, trimethylolpropane tri(meth)acrylate, trimethylolpropane polyethoxytri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, neopentyl glycol and hydroxypivalic acid ester diacrylate and neo Monomers such as the diacrylate of the ε-caprolactone adduct of an ester of pentyl glycol and hydroxypivalic acid can be mentioned. N-acryloyloxyethylhexahydrophthalimide, phenoxyethyl (meth)acrylate, and dicyclopentenyloxyethyl (meth)acrylate are preferred.
Epoxy (meth)acrylates are obtained by known methods by reacting epoxy resins with (meth)acrylic acid. The epoxy resin used as a raw material is not particularly limited, but is preferably a bifunctional or higher epoxy resin, such as resorcinol diglycidyl ether, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin. , phenol novolak 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, glycidyl amine type epoxy Resins, hydantoin-type epoxy resins, isocyanurate-type epoxy resins, phenol novolac-type epoxy resins 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 resin and resorcinol diglycidyl ether are preferable from the viewpoint of liquid crystal contamination. Moreover, the ratio of the epoxy group and the (meth)acryloyl group is not limited, and is appropriately selected from the viewpoint of process compatibility.
In addition, a partial epoxy (meth)acrylate in which a part of the epoxy group is acryl-esterified is preferably used. In this case, the acrylic ratio is preferably about 30 to 70%.

[Urethane (meth)acrylate]
Urethane (meth)acrylate has a flexible skeleton that is unique to the urethane structure, so the cured product has the characteristics of flexibility and low moisture permeability, and can follow the bending of flexible displays. A) is preferably used, more preferably having a polyester structure.
The urethane (meth)acrylate can be obtained by reacting (a) a polyol, (b) an organic polyisocyanate and (c) a hydroxyl group-containing (meth)acrylate and synthesizing it in a conventional manner. A catalyst such as a chemical compound is used.
In the synthesis of urethane (meth)acrylate, it is preferable to react 1.1 to 2.0 equivalents of isocyanate groups of component (b) with 1 equivalent of hydroxyl groups of component (a). It is particularly preferred to react .0 equivalents. The reaction temperature is preferably room temperature (25°C) to 100°C.
It is preferable to react 0.95 to 1.1 equivalents of hydroxyl groups in component (c) per equivalent of isocyanate groups in the reactants of components (a) and (b). The reaction temperature is preferably room temperature (25°C) to 100°C.

(a) Specific examples of polyols include tricyclodecanedimethanol, hydrogenated polybutadiene polyol, dimer diol, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, and 1,4-butanediol. , neopentyl glycol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-dodecanediol, 1,14-tetradecanediol, 1,16 -hexadecanediol, 1,18-octadecanediol, 1,20-icosanediol, 1-methyl-1,8-octanediol, 2-methyl-1,8-octanediol, 3-methyl-1,5-pentane Diol, 2,4-diethyl-1,5-pentanediol, cyclohexane-1,4-dimethanol, polyethylene glycol, polypropylene glycol, bisphenol A poly(n≈2-20) ethoxydiol, bisphenol A poly(n≈2 ~20) Diols (a-1) such as propoxydiol, these diols (a-1) and dibasic acids or their anhydrides (e.g. succinic acid, adipic acid, azelaic acid, sebacic acid, dimer acid, isophthalic acid, terephthalic acid Polyester diol (a-2) which is a reaction product with acid, phthalic acid, or their anhydrides, and the like can be mentioned. Preferred are tricyclodecanedimethanol, dimer diol, 1,9-nonanediol, 3-methyl-1,5-pentanediol and polyester diols thereof.
Component (a) may be used alone or in combination of two or more.

(b) Specific examples of organic polyisocyanate include tolylene diisocyanate, isophorone diisocyanate, 1,6-hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, xylylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-cyclohexyl Methane diisocyanate, xylylene diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, trimethylhexamethylene diisocyanate, dimeryl diisocyanate, 1,5-naphthalene diisocyanate, 3,3'-dimethyl-4,4'-diphenylene diisocyanate etc. can be mentioned. Tolylene diisocyanate, isophorone diisocyanate, 1,6-hexamethylene diisocyanate, and trimethylhexamethylene diisocyanate are preferred.

(c) Specific examples of hydroxyl group-containing (meth)acrylates include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 1,4-butanediol (meth)acrylate, and polyethylene glycol mono(meth)acrylate. acrylate, polypropylene glycol mono(meth)acrylate, pentaerythritol tri(meth)acrylate, ε-caprolactone adduct of 2-hydroxyethyl(meth)acrylate, 2-hydroxy-3-phenyloxypropyl(meth)acrylate, etc. can be done. Preferred are 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate and polyethylene glycol mono(meth)acrylate.

The lower limit of the weight average molecular weight of the urethane (meth)acrylate in terms of polystyrene in GPC is preferably 1000 or more, more preferably 2000 or more, particularly preferably 3000 or more, and most preferably 4000 or more. Also, the upper limit is preferably 10,000 or less, more preferably 8,000 or less, particularly preferably 7,000 or less, and most preferably 6,000 or less. By being in the above range, the viscosity of the adhesive for electronic parts is in an appropriate range while maintaining good flexibility and moisture permeability.

[Epoxy resin]
As an aspect of the present invention, it is more preferable that the component (A) contains an epoxy resin.
Although the epoxy resin is not particularly limited, a bifunctional or higher epoxy resin is preferable. 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 resins, isocyanurate-type epoxy resins, phenolic novolac-type epoxy resins having a triphenolmethane skeleton, diglycidyl-etherified products of bifunctional phenols such as catechol and resorcinol, diglycidyl-etherified products of bifunctional alcohols, and these Halides and hydrogenated products of Among these, bisphenol A type epoxy resin and resorcinol diglycidyl ether are preferable from the viewpoint of liquid crystal contamination.

[Polybutadiene compound]
It is also a preferred embodiment of the present invention to use a polybutadiene compound having an epoxy group or a (meth)acrylic group in the component (A). Polybutadiene compounds having epoxy groups are commercially available as JP-100 and JP-200 manufactured by Nippon Soda Co., Ltd., for example. Polybutadiene compounds having (meth)acrylic groups are commercially available as TEAI-1000 and TE-2000 manufactured by Nippon Soda Co., Ltd., for example.
The lower limit of the number average molecular weight of these polybutadiene compounds is preferably 500, more preferably 500, from the viewpoint of gas generation from adhesives for electronic parts and reduction of liquid crystal contamination when used as a liquid crystal peripheral material, for example, a liquid crystal sealant. 750, particularly preferably 1000. From the viewpoint of handleability, the upper limit of the number average molecular weight is preferably 10,000, more preferably 8,000, and particularly preferably 6,000.

A preferable content of component (A) is 30 to 99% by mass, more preferably 40 to 90% by mass, based on the total amount of the adhesive for electronic parts.

[(B) Thermosetting agent]
In the adhesive for electronic parts of the present invention, a thermosetting agent (hereinafter also simply referred to as "component (B)") is added as component (B) to improve reactivity.
Examples of component (B) include compounds having a carboxy group bonded to an aromatic ring in the molecule, polyvalent amines, polyvalent phenols, organic acid hydrazides, and the like. However, it is not limited to these. 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. In the case of aliphatic hydrazides, for example, 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(hydrazide dihydrazide and tris(1-hydrazinocarbonylmethyl)isocyanurate having a hydantoin skeleton such as dinocarbonoethyl)-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 (2-hydrazinocarbonylethyl) isocyanurate, tris (1-hydrazinocarbonylethyl) isocyanurate, tris (3-hydrazinocarbonylpropyl) isocyanurate, bis (2-hydrazinocarbonylethyl) isocyanurate, etc. I can give 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.
As the component (B), it is preferable to use a compound having a carboxy group bonded to an aromatic ring in the molecule. -(Aminomethyl)benzoic acid, 2-mercaptonicotinic acid.
Component (B) may be used alone or in combination of two or more. When component (B) is used in the adhesive for electronic components of the present invention, it is usually 1 to 70% by mass, preferably 1 to 30% by mass, more preferably 1 to 30% by mass of the total amount of the adhesive for electronic components. is 2 to 15% by mass.

[Measurement of cured product by dynamic viscoelasticity measuring device]
The adhesive for electronic parts of the present invention has a cured product with a loss tangent tan δ value of 0.1 or more, preferably 0.15, measured at a frequency of 5 Hz, tensile mode, and 25° C. with a dynamic viscoelasticity measuring device. 0.3 or more, and particularly preferably 0.3 or more. The upper limit is preferably 1.0 or less, more preferably 0.6 or less, particularly preferably 0.5 or less, and most preferably 0.4 or less. The value of loss factor tan δ is obtained from the ratio of loss modulus to storage modulus (JIS K 7244-1).
When the loss tangent tan δ is within the above range, the impact when the electronic component is dropped can be reduced, and the substrate is less likely to peel off.
The measurement of the cured product with a dynamic viscoelasticity measuring device was carried out by sandwiching the adhesive for electronic parts of the present invention between polyethylene terephthalate (PET) films to form a thin film having a thickness of 100 μm and exposing it to 3000 mJ/cm ² (measurement wavelength: After being irradiated with ultraviolet rays (365 nm, irradiation intensity: 100 mW/cm ² ), the film was placed in an oven and thermally cured at 120° C. for 40 minutes. Thereafter, the PET film was peeled off, and the cured sealant film was cut into strips of 50 mm×5 mm to obtain sample pieces. This sample piece was measured with a dynamic viscoelasticity measuring device (DMS-6100: manufactured by SII Nanotechnology Co., Ltd.) in a tensile mode at a frequency of 5 Hz and at 25°C.

[Moisture permeability measurement]
The moisture permeability of the cured product of the adhesive for electronic parts of the present invention is preferably 60 g/m ² ·24 hours or less, more preferably 50 g/m ² ·24 hours or less, and more preferably 40 g/m ^{2 .} - 24 hours or less is particularly preferred. This is to maintain performance for a long period of time in a high-temperature and high-humidity environment.
Moisture permeability is measured by a method conforming to JIS-K7129 (method A). The use of Lyssy L80-5000 manufactured by Systech Illinois makes it possible to measure according to JIS-K7129 (method A).
The measurement environment is 60° C. and 90% RH, and the measurement is performed using a cured product having a thickness of 300 μm prepared in the same manner as the measurement of the cured product using the dynamic viscoelasticity measuring device.

[(C) Thermal radical polymerization initiator]
The adhesive for electronic parts of the present invention can improve the curing speed and curability by containing (C) a thermal radical polymerization initiator (hereinafter also simply referred to as "component (C)").
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.

When the component (C) is used in the adhesive for electronic components of the present invention, it is preferably 0.0001 to 10% by mass, more preferably 0, based on the total amount of the adhesive for electronic components of the present invention. 0.0005 to 5 mass %, particularly preferably 0.001 to 3 mass %.

[(D) organic filler]
The adhesive for electronic parts 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 preferable 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-351S.
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 adhesive for electronic parts of the present invention, it is usually 5 to 50% by mass, preferably 5 to 40% by mass, of the total amount of the adhesive for electronic parts.

[(E) Curing accelerator]
The adhesive for electronic parts of the present invention can further improve reactivity by adding a curing accelerator (hereinafter also simply referred to as "component (E)"). Examples of curing accelerators include amines and imidazoles, and imidazoles are particularly preferred. Examples of imidazoles include 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, 2:3 adduct of 2-methylimidazole isocyanuric acid , 2-phenylimidazole isocyanuric acid adduct, 2-phenyl-3,5-dihydroxymethylimidazole, 2-phenyl-4-hydroxymethyl-5-methylimidazole, 1-cyanoethyl-2-phenyl-3,5-dicyanoethoxy and methylimidazole. When component (E) is used in the adhesive for electronic parts of the present invention, it is usually 0.01 to 5% by mass, preferably 0.1 to 1% by mass, of the total amount of the adhesive for electronic parts. .

[(F) photoradical polymerization initiator]
The adhesive for electronic parts of the present invention may contain a photoradical polymerization initiator (hereinafter also simply referred to as "component (F)") as component (F). The photoradical polymerization initiator is not particularly limited as long as it is a compound that generates radicals or acids upon irradiation with ultraviolet light or visible light and initiates a chain polymerization reaction. Examples include benzyl dimethyl ketal and 1-hydroxycyclohexyl phenyl ketone. , diethylthioxanthone, benzophenone, 2-ethylanthraquinone, 2-hydroxy-2-methylpropiophenone, 2-methyl-[4-(methylthio)phenyl]-2-morpholino-1-propane, 2,4,6- trimethylbenzoyldiphenylphosphine oxide, camphorquinone, 9-fluorenone, diphenyldisulfide and the like. Specifically, Omnirad 651, 184, 2959, 127, 907, 369, 379EG, TPO, 819, 754 (all manufactured by IGM Resins), Irgacure ^RTM OXE01, OXE02, OXE03, OXE04, (all manufactured by BASF ), Seikuol ^RTM Z, BZ, BEE, BIP, and BBI (all manufactured by Seiko Kagaku Co., Ltd.). Among these, IRGACURE ^RTM OXE01, OXE02, OXE03 and OXE04, which are oxime ester initiators, are preferred.
Also, from the viewpoint of liquid crystal contamination, it is preferable to use those having a (meth)acrylic group in the molecule, such as 2-methacryloyloxyethyl isocyanate and 1-[4-(2-hydroxyethoxy)-phenyl]- Reaction products with 2-hydroxy-2methyl-1-propan-1-one are preferably used. This compound can be produced and obtained by the method described in International Publication No. 2006/027982.
When component (F) is used in the adhesive for electronic parts of the present invention, it is usually 0.001 to 3% by mass, preferably 0.002 to 2% by mass, based on the total amount of the adhesive for electronic parts.

[(G) inorganic filler]
The adhesive for electronic parts of the present invention can improve adhesive strength and moisture permeability by containing (G) an inorganic filler (hereinafter also simply referred to as "component (G)").
Inorganic fillers include silica, silicon carbide, silicon nitride, boron nitride, calcium carbonate, magnesium carbonate, barium sulfate, calcium sulfate, mica, talc, clay, alumina, magnesium oxide, zirconium oxide, aluminum hydroxide, magnesium hydroxide, Calcium silicate, aluminum silicate, lithium aluminum silicate, zirconium silicate, barium titanate, glass fiber, carbon fiber, molybdenum disulfide, asbestos, preferably fused silica, crystalline silica, silicon nitride, boron nitride, calcium carbonate, Barium sulfate, calcium sulfate, mica, talc, clay, alumina, aluminum hydroxide, calcium silicate and aluminum silicate can be mentioned, with silica, alumina and talc being preferred. 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. 300 nm or less, and more preferably 300 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 component (G) is used in the adhesive for electronic parts of the present invention, it is usually 5 to 50% by mass, preferably 5 to 40% by mass, of the total amount of the adhesive for electronic parts. If the content of component (G) is less than 5% 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 component (G) is more than 50% by mass, the amount of component (G) is too large, so that it may become difficult to collapse, making it impossible to form a gap in the liquid crystal cell.

[(H) thiol compound]
The adhesive for electronic parts of the present invention may contain component (H) a thiol compound (hereinafter also simply referred to as component (H)). The addition of component (H) is very useful because it reacts with the epoxy groups and reactive double bonds of component (A).
Component (H) is not particularly limited as long as it is a compound having a thiol group in the molecule, but from the viewpoint of storage stability and reactivity, a thiol compound having a secondary thiol group is preferred.
Moreover, the number of thiol groups is preferably one having two or more thiol groups in the molecule (polyfunctional thiol compound), more preferably trifunctional or tetrafunctional.
The thiol equivalent of the thiol compound is preferably 80 or more, more preferably 100 or more, from the viewpoint of gas generation suppression. Also, the molecular weight is preferably 250 or more, more preferably 500 or more.
Component (H) may be used alone or in combination of two or more. When component (H) is used in the adhesive for electronic parts of the present invention, it is usually 0.5 to 30% by mass, preferably 0.5 to 20% by mass, based on the total amount of the adhesive for electronic parts.

[(O) other components]
Additives such as a silane coupling agent, a radical polymerization inhibitor, a pigment, a leveling agent, an antifoaming agent, and a solvent can be added to the adhesive for electronic parts of the present invention, if necessary.

[Silane coupling agent]
Examples of the silane coupling agent include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2-(3,4-epoxycyclohexyl)ethyl trimethoxysilane, 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 a silane coupling agent is used in the adhesive for electronic parts of the present invention, it is preferably 0.05 to 3% by mass based on the total amount of the adhesive for electronic parts.

[Radical polymerization inhibitor]
The radical polymerization inhibitor is not particularly limited as long as it is a compound that reacts with radicals generated from a radical photopolymerization initiator, a thermal radical polymerization initiator, or the like to prevent polymerization. Hindered phenol type, nitroso type and the like 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, tetrakis-[methylene-3-(3′,5′-di-t-butyl-4′-hydroxy phenylpropionate)methane], 1,3,5-tris(3′,5′-di-t-butyl-4′-hydroxybenzyl)-sec-triazine-2,4,6-(1H,3H,5H ) aluminum salt of trione, para-methoxyphenol, 4-methoxy-1-naphthol, thiodiphenylamine, N-nitrosophenylhydroxyamine, trade name Adekastab LA-81, tradename Adekastab LA-82 (manufactured by Adeka Co., Ltd.), and the like. but not limited to these. Of these, naphthoquinone-based, hydroquinone-based, nitroso-based, and piperazine-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.
In the adhesive for electronic parts of the present invention, when a radical polymerization inhibitor is used, it is preferably 0.0001 to 1% by mass, more preferably 0.001 to 0.5% by mass, based on the total amount of the adhesive for electronic parts. , 0.01 to 0.2% by weight are particularly preferred.

As an example of the method for obtaining the adhesive for electronic parts of the present invention, there is the following method. First, components (C), (F), a polymerization inhibitor and the like are heated and dissolved in component (A), if necessary. After cooling to room temperature, component (B), and optionally components (D), (E), (G) and (H), a silane coupling agent, an antifoaming agent, a leveling agent, a solvent, etc. are added. The adhesive for electronic parts of the present invention can be produced by uniformly mixing the components using a known mixing device such as a three-roll mill, sand mill, ball mill, etc., and filtering through a metal mesh.

Moreover, the adhesive for electronic parts of the present invention is very useful as a sealant for displays, particularly as a sealant for liquid crystals. An example of a liquid crystal display cell in which the adhesive 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 is prepared by arranging a pair of substrates having predetermined electrodes formed on the substrates facing each other at a predetermined interval, sealing the periphery with the liquid crystal sealing compound of the present invention, and Liquid crystal is sealed in the gap. 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 for the manufacturing method, after adding a spacer (gap control material) such as glass fiber to the liquid crystal sealant of the present invention, the liquid crystal sealant is applied to one of the pair of substrates using a dispenser or a screen printer. After that, temporary curing is performed at 80 to 120° 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 (measured wavelength: 365 nm, irradiation intensity: 100 mW/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 adhesive for electronic parts of the present invention is very suitable for use as an adhesive in fields requiring curability, adhesion to different adherends, and reliability against moist heat. For example, liquid crystal sealant, organic EL sealant, and touch panel adhesive.

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.

[Synthesis Example 1]
100 parts (0.28 mol) of commercially available benzopinacol (manufactured by Tokyo Kasei) was dissolved in 350 parts of dimethylformaldehyde. 32 parts (0.4 mol) of pyridine as a basic catalyst and 150 parts (0.58 mol) of BSTFA (manufactured by Shin-Etsu Chemical Co., Ltd.) as a silylating agent were added thereto, and the mixture was heated to 70° C. and stirred for 2 hours. The resulting reaction solution was cooled and 200 parts of water was added while stirring to precipitate the product and deactivate the unreacted silylating agent. After separating the precipitated product by filtration, it was thoroughly washed with water. The resulting product was then dissolved in acetone and recrystallized by adding water for purification. 105.6 parts of the desired 1,2-bis(trimethylsiloxy)-1,1,2,2-tetraphenylethane was obtained (yield 88.3%).

[Examples 3, 4, 6 , Comparative Example 1 , Reference Examples 1, 2, 5 ]
Components (A), (C), (F), and (O) were heated and mixed at 90° C. in the proportions shown in Table 1 below, then cooled to room temperature, and components (B), (D), and (E) were mixed. , (G), (H), and (O) were added, stirred, dispersed in a three-roll mill, and filtered through a metal mesh (635 mesh) to prepare an adhesive for electronic parts.

[Glass transition temperature (Tg)]
The adhesives for electronic components produced in Examples , Comparative Examples , and Reference Examples were sandwiched between polyethylene terephthalate (PET) films to form a thin film having a thickness of ¹⁰⁰ μm. After being irradiated with ultraviolet rays having an intensity of 100 mW/cm ² , it was placed in an oven and thermally cured at 120° C. for 40 minutes. Thereafter, the PET film was peeled off, and the cured sealant film was cut into strips of 50 mm×5 mm to obtain sample pieces. This sample piece was measured with a dynamic viscoelasticity measuring device (DMS-6100: manufactured by SII Nanotechnology Co., Ltd.) in a tensile mode at a frequency of 5 Hz and at 25°C. The loss factor tan δ was calculated from the ratio of loss modulus to storage modulus (JISK7244-1). Results are shown in Table 1.

[Moisture Permeability]
The adhesives for electronic components produced in Examples , Comparative Examples , and Reference Examples were sandwiched between polyethylene terephthalate (PET) films to form a thin film having a thickness of ³⁰⁰ μm. After irradiating with ultraviolet rays having an intensity of 100 mW/cm ² ), the film was placed in an oven and heat-cured at 120° C. for 40 minutes. The moisture permeability of the sample at 60° C. 90% was measured with a moisture permeability meter (manufactured by Lyssy: L80-5000). Results are shown in Table 1.

[Adhesion strength]
An alignment film liquid (Nissan Chemical Industries, Ltd.: NRB-U738) was spin-coated on a glass substrate with an ITO film, calcined on a hot plate at 80° C. for 3 minutes, and baked in an oven at 230° C. for 30 minutes. Further, the substrate with the alignment film was irradiated with ultraviolet rays of 500 mJ/cm ² (measurement wavelength: 254 nm) using a UV irradiation machine, and baked in an oven at 230° C. for 30 minutes.
1 g of glass fiber of 5 μm as a spacer is added to 100 g of adhesives for electronic parts produced in Examples , Comparative Examples and Reference Examples, and mixed and stirred. On ^the glass substrate coated with the alignment film, this sealant for display was coated so as to reproduce a corner portion of 1 cm x 1 cm, and the opposing alignment film-coated substrates were bonded together. After being irradiated with ultraviolet rays having a wavelength of 365 nm, it was placed in an oven and thermally cured at 120° C. for 40 minutes. The peeling adhesion strength of the orientation film-coated glass substrate was measured with a bond tester (manufactured by Seishin Shoji Co., Ltd.: SS-30WD) by pressing the corner portion.

[Preparation of liquid crystal cell for evaluation]
An orientation film was applied to the substrate with the transparent electrode in the same manner as described above to prepare a substrate with the orientation film and the transparent electrode. A main seal and a dummy seal were dispensed so that the line width after bonding the obtained adhesive for electronic parts to the substrate was 0.6 mm, and then microdroplets of liquid crystal (JC-5015LA; manufactured by JNC Co., Ltd.) were applied. was dropped in the frame of the seal pattern. Furthermore, an in-plane spacer (manufactured by Natoco Co., Ltd.: Natoco Spacer KSEB-525F; gap width after bonding: 5 μm) was dispersed on another substrate with an alignment film and a transparent electrode, and then heat-fixed, and then vacuumed using a bonding device. Inside, it was pasted with the previous 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 irradiated with ultraviolet rays of 3000 mJ/cm ² (measurement wavelength: 365 nm, irradiation intensity: 100 mW/cm ² ) from a UV irradiation machine, and then placed in an oven. The composition was heat-cured at 120° C. for 40 minutes to prepare a liquid crystal test cell for evaluation having a size of 3×4.2 cm.

[Drop test]
A liquid crystal test cell for evaluation was dropped from a height of 75 cm above the ground with a weight attached to one corner of the test cell and adjusted so that the corner of the test cell hit the ground. The peeling state of the sealant after dropping was scored as follows, and the average value of five times was used as the test result. Results are shown in Table 1.
5: No peeling of the adhesive 4: Very little peeling of the adhesive 3: About 1/3 of the two sides of the adhesive peeled off 2: Almost two sides of the adhesive peeled off 1: The adhesive completely peeled off

From the results in Table 1, it was confirmed that the adhesive for electronic components of the present invention had good drop test results. On the other hand, it was confirmed that the drop test result of Comparative Example 1 was poor even though the adhesive strength was higher than that of Example 4.

The adhesive for electronic parts of the present invention is useful as an adhesive for electronic parts for various display applications because it has excellent drop impact resistance and excellent low moisture permeability.

Claims (4)

(A) a curable compound , (B) a thermosetting agent, (C) a thermal radical polymerization initiator and/or (F) a photoradical polymerization initiator, and an adhesive for electronic components,
The component (A) contains partial epoxy (meth) acrylate and urethane (meth)acrylate,
The urethane (meth)acrylate is a polyester urethane (meth)acrylate,
The weight average molecular weight of the urethane (meth)acrylate is 1000 or more and 10000 or less,
The content of the urethane (meth)acrylate (A) is 20% by mass or more and 35% by mass or less in the total amount of the curable compound,
In an environment of 60° C. and 90% RH, the moisture permeability of a cured product with a thickness of 300 μm measured according to JIS-K7129 is 60 g/m ² ·24 hours or less,
An adhesive for electronic parts having a loss tangent tan δ of 0.1 or more when measured with a dynamic viscoelasticity measuring device at a frequency of 5 Hz and a tension mode at 25°C. Electronic parts bonded with a cured product obtained by curing the adhesive for electronic parts according to claim 1 . A liquid crystal sealant using the adhesive for electronic parts according to claim 1 . A liquid crystal display cell adhered using the liquid crystal sealant according to claim 3 .