JP2009155589A - Curable composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a curable resin composition excellent in low temperature quick curing property, heat resistance, shaded part curing property and reducing liquid crystal pollution as a material suitable for sealing a liquid crystal display device manufactured by a dripping method. <P>SOLUTION: The curable resin composition contains the following (A)-(D) components as essential components: (A) a (meth)acrylic compound having at least one (meth)acrylic group in one molecule, (B) a photoinitiator, (C) epoxy resin having at least one glycidyl group in one molecule, and (D) a curing agent comprising an aminoalkylimidazole compound. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a curable composition, and more particularly to a curable composition suitable as a sealant or adhesive for liquid crystal display devices used in devices such as notebook PCs, televisions, and mobile phones. In more detail, this invention relates to the curable composition suitable for sealing of the liquid crystal display device manufactured by a dripping system (ODF).

  In recent years, liquid crystal display devices have been used in devices such as notebook PCs and televisions, and the size of liquid crystal display devices has been increasing. As a manufacturing method of these liquid crystal display devices, a dropping method (ODF) with higher productivity and extremely high utilization efficiency of expensive liquid crystal materials has been proposed (Patent Documents 1 and 2). Specifically, a liquid crystal sealing sealant called a main seal is applied to one substrate so as to form a bank-like frame, and the liquid crystal composition is dropped inside the frame while the sealant is uncured. After that, the other substrate is bonded and the sealant is cured to manufacture a liquid crystal display device.

  However, in the dripping method, the uncured main seal is in contact with the liquid crystal composition. For this reason, since the time required for curing is relatively long when a conventional thermosetting sealant is used, the liquid crystal material and the alignment film, which is a peripheral member, are contaminated by elution of the sealant component into the liquid crystal composition. Since the display quality of the display device is remarkably lowered, it has not been practically used.

  Then, in order to shorten the contact time between the uncured main seal and the liquid crystal composition as much as possible, a photo-curing main seal has been proposed (Patent Document 3). However, in the dripping method, because the metal wiring part of the TFT substrate of the liquid crystal display device and the black matrix part of the color filter substrate exist, the light-shielding part that is not exposed to light remains as an uncured part without curing the sealant. There is a problem that the display quality of the apparatus is deteriorated.

  As described above, since the thermosetting method and the photocuring method have respective problems, a number of two-stage curing type main seals using both photocuring and thermosetting have been proposed as a solution (Patent Document 4, Patent Document). 5, Patent Document 6, Patent Document 7, Patent Document 8, etc.). The method of using the two-stage curing type main seal by light and heat is such that first, the sealing agent sandwiched between two glass substrates is irradiated with light to be cured in the first stage, and then heated. It is characterized by a second stage of heat curing.

  However, the main seal described in Patent Document 7 is an acrylic ester or methacrylic ester as a main component and polymerizes by a radical polymerization mechanism. Therefore, the adhesive strength to glass, particularly in a high-temperature and high-humidity environment, decreases the adhesive strength. It is large and has a problem in reliability as compared with the thermosetting type. Therefore, a sealing agent using a combination of (meth) acrylic acid ester and an epoxy resin as a main component is used in Patent Document 9, Patent Document 10, Patent Document 11, Patent Document 12, etc., with the two-stage curing type using light and heat as it is. Has been proposed.

  However, the main seal as described above has problems such as seal puncture due to a decrease in the viscosity of the sealant and elution of the sealant component into the liquid crystal in the thermosetting process performed after photocuring. Therefore, the thermosetting agent used for the epoxy resin is required to have characteristics such as low temperature curability and fast curability.

  Curing agents that satisfy the above required characteristics include certain polyamine curing agents and certain imidazole curing agents. However, any of the cured products using polyamine curing agents cannot maintain practical strength because the glass transition point is as low as 100 ° C. or less. In addition, in a general imidazole-based curing agent, there is a problem that liquid crystal contamination occurs in a portion where the photocurable resin that is a sealing agent does not react due to the shadow. In order to improve the shadow curing property, it is conceivable to add a (meth) acrylic ester thermal initiator, but if the thermal initiator is brought into contact with the liquid crystal composition, the liquid crystal composition will be soiled, Moreover, the storage stability of curable resin composition is reduced.

JP-A 63-179323 JP-A-10-239694 JP-A-1-243029 JP 58-105124 A Japanese Patent Laid-Open No. 1-266610 Japanese Patent Laid-Open No. 7-13175 JP-A-8-328026 Japanese Patent Laid-Open No. 9-5759 JP 2001-133794 A JP 2004-37937 A JP 2004-61925 A JP-A-5-295087

  The object of the present invention is to solve the above-mentioned problems of the prior art, and in particular, it is excellent in storage stability and coating workability, and can give a high-quality cured product in a short time. Another object of the present invention is to provide a two-stage curable resin composition suitable as a sealing agent for sealing liquid crystal display devices.

  In order to solve the above problems, the first embodiment of the present invention is as follows. (A) (meth) acrylic compound having at least one (meth) acrylic group in one molecule, (B) photoinitiator, (C) 1 It is a curable resin composition containing, as essential components, an epoxy resin having at least one glycidyl group in the molecule and (D) a curing agent comprising an aminoalkylimidazole compound.

  The 2nd form of this invention is the curable resin composition of the said 1st form whose aminoalkyl imidazole compound of (D) component is an aminoalkyl imidazole compound shown by General formula (1).

(Here, R is a hydrogen atom or a monovalent hydrocarbon group, R _{1 to} R ₃ are each independently a hydrogen atom or a hydrocarbon group which may have a substituent, and n is 2 or 3. )

  In the third embodiment of the present invention, the component (D) comprises an aminoalkylimidazole compound (d1), a diamine compound (d2) having a cyclic structure in advance, urea (d3), and an average of two glycidyl groups in the molecule. It is a curable resin composition of the 1st or 2nd form which exists in the form of the processed material heat-processed with the epoxy resin (d4) which has this.

  The fourth aspect of the present invention is the curing according to any one of the first to third aspects, wherein the component (D) is present at 1 to 20 parts by weight per 100 parts by weight in total of the components (A) to (C). It is an adhesive resin composition.

  According to a fifth aspect of the present invention, a partially esterified epoxy (meta) obtained by subjecting (meth) acrylic acid to a partial esterification reaction with an epoxy resin having (A) component having at least two glycidyl groups in one molecule. ) It is a curable resin composition of the said 1st-4th form which is an acrylic compound.

  The 6th form of this invention is the sealing compound for bonding of the liquid crystal display device by the dripping system which consists of a curable resin composition of the form in any one of the 1st-5th.

  In the present invention, the expression “(meth) acrylic acid” means “acrylic acid and / or methacrylic acid” as is well known. The meaning content of “(meth)” in the indications such as “(meth) acrylic compound” and “(meth) acrylate” is the same.

  The curable resin composition of the present invention is based on a reaction with an active hydrogen moiety of an aminoalkyl group while maintaining a low temperature rapid curing property and heat resistance peculiar to imidazoles by using a thermosetting agent composed of an aminoalkylimidazole compound. By curing the (meth) acrylic group, a light / thermosetting resin composition having good shadow curable properties can be obtained. In addition, when the curable resin composition of the present invention is used as a sealing agent for laminating a liquid crystal display device, the liquid crystal contamination is low, the coating workability to a substrate is excellent, and the storage stability is good. Furthermore, it becomes a sealing agent having a high adhesive force. By applying this sealant to the dropping method, it is possible to manufacture a liquid crystal display device with improved display quality, yield, and productivity.

  By combining the component (D) of the present invention with the component (A) and the component (C), not only acts as an epoxy curing agent for the component (C), but the alkylamino group present in the structure can By reacting with the component (A) in the shadow that has not been cured by irradiation, this is cured, and as a result, the uncured component (A) does not elute into the liquid crystal, and thus a high-quality liquid crystal display device is obtained. Can be manufactured.

  The acrylic compound having at least one (meth) acryl group in one molecule used in the present invention is a radical polymerizable monomer or oligomer having a (meth) acryl group at the molecular end or side chain. There is no particular limitation, for example, polyester (meth) acrylate, epoxy (meth) acrylate, urethane (meth) acrylate, polyether (meth) acrylate, polybutadiene (meth) acrylate, silicon (meth) acrylate, etc. Examples include various polymerizable monomers and oligomers.

  Here, as a polyester (meth) acrylate oligomer, for example, by esterifying the hydroxyl group of a polyester oligomer having a hydroxyl group at both ends obtained by condensation of a polyvalent carboxylic acid and a polyhydric alcohol with (meth) acrylic acid, Or it can obtain by esterifying the hydroxyl group of the terminal of the oligomer obtained by adding an alkylene oxide to polyhydric carboxylic acid with (meth) acrylic acid. Epoxy (meth) acrylate oligomers are compounds that have been modified with (meth) acrylic by an ester bond by reacting (meth) acrylic acid with the oxirane ring of a relatively low molecular weight bisphenol-type epoxy resin or novolak-type epoxy resin, for example. Obtainable.

  Further, a carboxyl-modified epoxy (meth) acrylate oligomer obtained by partially modifying this epoxy (meth) acrylate-based oligomer with a dibasic carboxylic acid anhydride can also be used. The urethane (meth) acrylate oligomer can be obtained, for example, by esterifying a polyurethane oligomer obtained by reaction of polyether polyol or polyester polyol and polyisocyanate with (meth) acrylic acid, and polyol (meth) The acrylate oligomer can be obtained by esterifying the hydroxyl group of the polyether polyol with (meth) acrylic acid.

  These oligomers are appropriately selected according to the use of the photocurable material. For example, in fields that require photocurability, hardness, heat resistance, electrical properties, etc., epoxy (meth) acrylic compounds are mainly used, and flexibility, toughness, wear resistance, chemical resistance, etc. are required. In the field, urethane (meth) acrylic compounds are mainly used. In fields where low viscosity, handling properties, and low prices are required, polyester (meth) acrylic compounds and polyether (meth) acrylic compounds are mainly used, and alkali developability, hardness, heat resistance, etc. are required. In the field of solder resists and the like, carboxyl group-modified epoxy (meth) acrylate compounds are mainly used.

  Other photopolymerizable oligomers include a highly hydrophobic polybutadiene (meth) acrylate oligomer having a (meth) acryl group in the side chain of the polybutadiene oligomer, a silicone (meth) acrylate oligomer having a polysiloxane bond in the main chain, There are aminoplast resin (meth) acrylate oligomers obtained by modifying aminoplast resins having many reactive groups in a small molecule, and they are used in fields where each characteristic can be exhibited. This photopolymerizable oligomer may be used individually by 1 type, and may be used in combination of 2 or more type. Any of the photopolymerizable oligomers has a relatively high viscosity, and the viscosity increases as the molecular weight increases. Therefore, when this photopolymerizable oligomer is photocured alone, the crosslinking reaction may not proceed sufficiently, and conversely, the crosslinking density may increase and the cured product may become brittle. Therefore, in the present invention, a monofunctional or polyfunctional photopolymerizable monomer can be used in combination for adjusting the viscosity, promoting the photocrosslinking reaction, adjusting the crosslink density of the cured product, and the like.

  In the present invention, as the component (A), a partially esterified epoxy (meth) acryl obtained by reacting (meth) acrylic acid with a part of glycidyl groups of an epoxy resin having at least two glycidyl groups in one molecule. It is effective to use a compound. This is useful, for example, in order to minimize the unreacted (meth) acrylic resin in the shadow that could not be photocured when the curable composition of the present invention is used as a liquid crystal sealant.

  The epoxy resin used in this esterification reaction is not particularly limited as long as it is an epoxy resin having at least two glycidyl groups, and among these, bisphenol A type, F type or novolac type epoxy resins can be preferably used. . Among these, it is preferable to use a liquid at room temperature in consideration of handling during handling, easiness, and the like. These epoxy resins may be used alone or in combination of two or more.

  In the partially esterified epoxy (meth) acrylic resin, the equivalent ratio of (meth) acrylic acid to the equivalent of the glycidyl group of the epoxy resin can be arbitrarily set in the epoxy resin having at least two epoxy groups in the molecule. It can be obtained by selective esterification. In this invention, it is preferable when this esterification rate shall be 20-80 equivalent%. As a method for synthesizing a partially esterified epoxy (meth) acrylic resin, an epoxy resin and (meth) acrylic acid are mixed at a predetermined equivalent ratio, and an esterification catalyst (for example, benzyldimethylamine, triethylamine, benzyltrimethylammonium chloride, Phenylphosphine, triphenylstibine, etc.) and a polymerization inhibitor (for example, methoquinone, hydroquinone, methylhydroquinone, phenothiazine, dibutylhydroxytoluene, etc.) are added and reacted.

  For example, when an esterification reaction of a bifunctional epoxy resin and (meth) acrylic acid is carried out at an equivalent ratio of 1: 1, usually 50 equivalent% partially esterified epoxy (meth) acrylic resin and 25 equivalent% unreacted A bifunctional epoxy resin, 25 equivalent% of a bifunctional (meth) acrylic resin (fully esterified product) is formed. In the present invention, the above three types of components are distinguished and their blending ratios are shown.

  As described above, the present invention includes an arbitrary amount of a completely esterified product in the process of synthesizing a partially esterified epoxy (meth) acrylic resin, and the amount of this product is added to the component (A). The amount of the partially esterified epoxy (meth) acrylic resin is 50% by weight or more, preferably 65% by weight or more in the component (A), thereby exhibiting its effect. Moreover, it is also possible to control the production | generation ratio of the said 3 types of product synthesize | combined by selecting the equivalent ratio of a (meth) acrylic acid made to react with an epoxy resin, a catalyst, etc.

  As the (B) photoinitiator used in the present invention, a conventionally known radical-generating photopolymerization initiator can be used. Specifically, benzophenone, 2,2-diethoxyacetophenone, benzyl, benzoyl isopropyl ether, benzyl dimethyl ketal, 1-hydroxycyclohexyl phenyl ketone, thioxanthone benzyl dimethyl ketal, 1-hydroxycyclohexyl phenyl ketone, diethyl thioxanthone, 2-ethyl Anthraquinone, 2-hydroxy-2-methylpropiophenone, 2-methyl- [4- (methylthio) phenyl] -2-morpholino-1-propane, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, etc. can be used. . In particular, it is useful to use a radical-generating photopolymerization initiator obtained by a urethanization reaction between a hydroxyl group-containing benzoyl compound and an isocyanate compound represented by the following general formula (3). This is preferably used in the present invention because the amount of outgas generated during photocuring is small and the contamination of the liquid crystal material is extremely low.

In the formula, R ₁ is a hydroxyalkoxy group such as a hydroxyl group, a hydroxymethoxy group, a hydroxyethoxy group, and a hydroxyprop group, and R ₂ and R ₃ are alkyl groups such as a methyl group, an ethyl group, and a propyl group. . The number of carbon atoms of the alkyl group is not particularly limited, but is preferably 6 or less. R ₁ may be bonded to any position of ortho, meta, and para.

  The blending ratio of the photopolymerization initiator (B) to the component (A) used in the present invention is preferably 1 to 10 parts by weight, particularly preferably 1.5 to 5 parts by weight per 100 parts by weight of the component (A). Part. When the blending amount of the photoinitiator is less than 1 part by weight, the photocuring reaction is not sufficient, and when it is more than 10 parts by weight, the amount of the initiator is too large, causing contamination of the initiator with respect to the liquid crystal.

  As the (C) epoxy resin used in the present invention, the same epoxy resin as that used for synthesizing the partially esterified epoxy (meth) acrylic resin which is a kind of the component (A), and other bisphenol A type are used. Conventionally known epoxy resins such as epoxy resins, bisphenol F type epoxy resins, novolac type epoxy resins, cycloaliphatic epoxy resins and the like can be mentioned. These epoxy resins of component (C) are used in the range of 80 to 250 parts by weight, preferably 90 to 200 parts by weight, per 100 parts by weight of component (A).

  When the partially esterified epoxy (meth) acrylic resin selected as component (A) is synthesized, the product mixture usually contains an unreacted epoxy resin and a completely esterified product in addition to the partially esterified product. When the reaction epoxy resin is present, the amount is added as the amount of the epoxy resin as the component (C). When the amount of the epoxy resin of component (C) is less than 90 parts by weight, sufficient adhesive strength cannot be obtained, and when it exceeds 250 parts by weight, an uncured epoxy resin is formed during the thermosetting process after UV temporary curing. Elution into the liquid crystal material causes problems such as display defects.

  The aminoalkyl constituting the curing agent comprising (D) an aminoalkylimidazole compound used in the present invention has a basic structure in which an alkyl group having a primary or secondary amino group is bonded to the nitrogen atom constituting the imidazole ring. And acts mainly as a curing agent for epoxy groups and (meth) acryl groups in the composition of the present invention. As the aminoalkylimidazole compound, a compound having a structure represented by the following general formula (1) is particularly preferable.

(Where R is a hydrogen atom or a monovalent hydrocarbon group (preferably an alkyl group having 1 to 3 carbon atoms), and R _{1 to} R ₃ are each independently a hydrocarbon which may have a hydrogen atom or a substituent. Group (preferably an alkyl group having 1 to 3 carbon atoms), and n is 2 or 3.)

  In the present invention, the addition amount of the component (D) is preferably 1 to 20 parts by weight, particularly preferably 5 to 15 parts by weight, based on 100 parts by weight of the total addition amount of the components (A) and (C). . If it is less than 1 part by weight, the curability of the component (A) cannot be obtained during heating, and if it exceeds 20 parts by weight, the glass transition temperature of the cured product is lowered.

  As the component (D), an aminoalkylimidazole compound may be used in combination with other components. In particular, a heat-treated product with a diamine compound (d2) having a cyclic structure, urea (d3), and an epoxy resin (d4) having an average of two glycidyl groups in the molecule (see JP-A-2005-206744) ) Is preferably used. This treated product is commercially available under the name FXQ-1110 from Fuji Chemical Industry Co., Ltd.

  The curable composition of the present invention may be blended with an appropriate amount of other additives as long as the characteristics are not impaired. Examples of other additives include sensitizers, colorants such as pigments and dyes, storage stabilizers, polymerization inhibitors, facial agents, antifoaming agents, coupling agents, organic and inorganic fillers, and the like. Examples of fillers include fused silica, crystalline 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, etc., 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, and more preferably fused silica, crystalline silica, and talc. Those having an average particle diameter of 5 μm or less are effective. For example, the gap of the glass substrate of the liquid crystal display device needs to be made smaller in order to realize the high-speed response, and specifically 5 μm or less is required. If the average particle size is larger than 5 μm, the currently required liquid crystal display device cannot be produced.

  Further, the curable composition of the present invention is added with a coupling agent for improving adhesiveness, a spacer agent for ensuring a predetermined clearance, a storage stabilizer and the like in addition to the above components. Also good. Examples of the silane coupling agent include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane 2- (3,4-epoxycyclohexyl) ethyltrimethoxy. Silane, N-phenyl-γ-aminopropylmethyldimethoxysilane, N- (2-aminoethyl) 3-aminopropylmethyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, vinyltrimethoxy Silane, N- (2- (vinylbenzylamino) ethyl) 3-aminopropyltrimethoxysilane hydrochloride, 3-methacryloxypropyltrimethoxysilane, 3-chloropropylmethyldimethoxysilane, 3-chloropropyltrime Silane coupling agents such as Kishishiran like. These silane coupling agents may be used in combination of two or more. By using a silane coupling agent, an adhesive strength is improved, and a liquid crystal sealing agent having excellent moisture resistance reliability can be obtained.

  Examples of the storage stabilizer include trisnonyl phenyl phosphite, triphenyl phosphite, diisooctyl octyl phenyl phosphite, diphenyl isooctyl phosphite, diphenyl isodecyl phosphite, phenyl diisodecyl phosphite, triisodecyl phosphite. Phyto, triisooctyl phosphite, trilauryl phosphite, alkylallyl phosphite, trialkyl phosphite, allyl phosphite, diisodecyl pentaerythritol diphosphite, bis (2,4-di-t-butylphenyl) pentaerythritol di Phosphate, distearyl pentaerythritol diphosphite, phosphate derivatives such as distearyl pentaerythritol diphosphite, tris-o-phenylene Suvorate, bis-o-phenylene pyroborate, bis-2,3-dimethylethylenepyreborate, bis-2,2-dimethyltrimethylene pyroborate, 2,2-oxybis (5,5-dimethyl-1,3, Boric acid ester derivatives such as 2-dioxaborinane). When these are used together with a phenolic compound, the storage stability is greatly improved.

  In order to obtain a liquid crystal sealant, the component (B) and the component (C) are first dissolved and mixed in the component (A), and then the component (D) and a coupling agent as described above as a thermosetting agent are added to the mixture. It is preferable to add a predetermined amount of a filler, a storage stabilizer and the like, and to mix them uniformly by a known mixing apparatus such as a roll mill, a sand mill, a ball mill or the like. By this method, the liquid crystal sealant of the present invention can be produced.

〔Example〕
Hereinafter, the present invention will be described in detail with reference to examples.
<Synthesis of partially esterified epoxy (meth) acrylic resin>

(Synthesis Example 1)
In a reaction vessel, 312 g (2.0 equivalents) of bisphenol F-type epoxy resin (Epiclon 830-LVP manufactured by Dainippon Ink and Chemicals, Inc.), 72 g (1.0 equivalent) of acrylic acid, 0.2 g of hydroquinone, Then, 1.5 g of benzyldimethylamine was charged, and the reaction was carried out at 110 to 120 ° C. for 8 hours while blowing air to obtain the desired reaction product. (Bisphenol F type epoxy resin and acrylic acid are equivalent in molar ratio)
[Evaluation of Reaction Product] The obtained reaction product was dissolved in chloroform, filtered through a 0.45 μm membrane filter, and injected into a preparative HPLC apparatus, and the confirmed peak was fractionated. Next, the fractions are bisphenol F type diglycidyl ether monoacrylate (partially esterified epoxidized acrylate resin), bisphenol F type diglycidyl ether diacrylate (epoxy acrylate), bisphenol F type diglycidyl ether (epoxy resin), In a molar ratio of about 2: 1: 1.

(Synthesis Example 2)
In a reaction vessel, 350 g (2.0 equivalents) of a phenol novolac type epoxy resin (Epicoat 152 manufactured by Japan Epoxy Resin Co., Ltd.), 72 g (1.0 equivalent) of acrylic acid, 0.2 g of hydroquinone, and benzyldimethyl Amine 1.5 g was charged and reacted in the same manner as in Synthesis Example 1 to obtain the desired reaction product. Moreover, when the reaction product was evaluated in the same manner as in Synthesis Example 1, phenol novolac glycidyl ether half acrylate (partially esterified epoxidized acrylate resin), phenol novolac glycidyl ether acrylate (epoxy acrylate) and It was confirmed that phenol novolac-type diglycidyl ether (epoxy resin) was contained in a molar ratio of about 2: 1: 1.

<Adjustment of curable composition>
Each component was mixed by the mixture ratio shown in Table 1, and each sample (Example 1, 2 and Comparative Examples 1-3) was adjusted. The addition amount of the amine compound used as the component (D) was added so that the sum of the reactive groups in the component (D) was approximately the same as the reactive groups in the component (C). In addition, the addition amount in a table | surface is a basis of weight unless there is particular notice. Moreover, each component used for the Example and the comparative example is as follows.

-Partially esterified epoxy (meth) acrylic resin: The compounds of Synthesis Examples 1 and 2 are used.
Epoxy resin: Novolac type epoxy resin (trade name Epicoat 152, manufactured by Japan Epoxy Resin Co., Ltd.)
Bisphenol A / F type epoxy mixed resin (trade name Epicron EXA-835LV, manufactured by Dainippon Ink & Chemicals, Inc.)
-Radiation-generating photopolymerization initiator PI-1: By urethanation reaction of 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one and isophorone diisocyanate Obtained photopolymerization initiator / phosphate ester derivative (storage stabilizer): JPP-13R (product of Johoku Chemical Industry Co., Ltd.)
・ Phenolic resin (storage stabilizer): HF-1M (Maywa Kasei Co., Ltd. product)
Component (D): Curing agent comprising an aminoalkylimidazole compound (processed by heat-treating 1- (2-aminoethyl) -2-methylimidazole in the presence of isophoronediamine, bisphenol F type epoxide and urea): FXR -1110 (product of Fuji Chemical Industry Co., Ltd.)
Aliphatic polyamine compound: EH-4342S (Asahi Denka Kogyo Co., Ltd. product)
・ Aromatic amino group-containing imidazole derivatives: 2MA-OKPW (product of Shikoku Chemicals)
・ Inorganic filler: Talc (trade name Microace L-1 manufactured by Nippon Talc)

Each sample obtained was evaluated as follows, and the results are shown in Table 1.
[Viscosity]: The viscosity at 25 ° C. was measured using an EHD viscometer (manufactured by Toki Sangyo Co., Ltd.). (According to JISK5600-2-3)
[Viscosity stability test]: Each liquid crystal sealant obtained was allowed to stand in a thermostatic bath at 25 ° C., and the initial viscosity and the viscosity after 24 hours were measured and compared with the above viscometer to determine the storage stability of the resin. evaluated.
[Adhesive strength test]: (Test piece preparation method) A curable resin composition having the composition shown in Table 1 was applied to a glass plate (100 mm x 25 mm x 5 mm) according to the method defined in JIS-K-6850, The sample was bonded to the other glass plate, irradiated with ultraviolet rays with a cumulative light quantity of 30 kJ / m ² using a high-pressure mercury lamp with a lamp height of 15 cm and heated at 120 ° C. for 1 hour, and used for evaluation as a test piece. .

(Evaluation method) Fix both ends of the test piece to the chuck, apply a tensile shear load at a tensile speed of 50 mm / min, measure the maximum load until the test piece breaks, and calculate the tensile shear bond strength from the following formula did.
(Shear bond strength calculation method) Ts = Fs / A
Ts: Tensile shear bond strength Pa {kgf / cm ² }
Fs: Maximum load N {kgf}
A: Adhesive area m ² {cm ² }

[Reliability Test]: The same measurement was performed on the test piece prepared by the above-described method, which was left in a PCT (121 ° C., 2 atm) atmosphere for 12 hours.
[Liquid Crystal Contamination Test]: As a method for evaluating liquid crystal contamination in the present invention, a liquid crystal composition was measured by measuring a phase transition temperature. As a test method, 0.15 g of the curable resin composition of the present invention was put in a sample bottle, and a sample bottle that was not irradiated with ultraviolet rays with an integrated light amount of 30 kJ / m ² was prepared. Each of these was heated and cured at 120 ° C. for 1 hour, and then 1.5 g of a liquid crystal composition (ZLI-4792 manufactured by Merck) was added. These were put into a 100 ° C. oven for 1 hour to promote dissolution of the curable resin composition. Thereafter, the mixture was allowed to cool at room temperature for 1 hour, and the liquid crystal composition as the supernatant liquid was taken out from the sample bottle after the treatment, and the phase transition temperature of the liquid crystal was measured using DSC220 (manufactured by Seiko Instruments). Here, the liquid crystal composition treated in contact with the curable resin composition of the present invention (hereinafter, abbreviated as contact liquid crystal) was processed in the same manner without contacting the phase transition temperature (hereinafter referred to as non-contact liquid crystal). As a result of comparison with the phase transition temperature of (abbreviated)), the case where the value of the phase transition temperature of the contact liquid crystal does not decrease by 0.5 ° C. or more is indicated as “good”, and the case where the value decreases by 0.6 ° C. or more is determined as “fail”. Represented and judged.

  As can be seen from Table 1, it can be seen that Examples 1 and 2 are changes in viscosity that are not problematic in terms of work and have high adhesive strength. Moreover, since all use aminoalkyl imidazoles as a thermosetting agent, it turns out that liquid crystal contamination property is low, and the adhesive strength after a glass transition point and a reliability test is high. Since Comparative Example 1 uses a polyamine compound as a thermosetting agent, the liquid crystal contamination is low by reacting with an acrylic group, but the glass transition point is low and the adhesive strength after the reliability test is reduced. I understand. Comparative Example 2 uses an imidazole derivative having no aminoalkyl group as a thermosetting agent. In this imidazole derivative, there is a primary amino group, which is an aromatic amino group and does not react with the acrylic group, and therefore, the uncured part does not crosslink and cure at the time of heat curing. I understand that it is expensive. In Comparative Example 3 in which imidazoles and an aliphatic polyamine compound were mixed and used as a thermosetting agent, a sufficient glass transition temperature was not obtained due to the effect of mixing the aliphatic polyamine compound, and as a result, the adhesive strength after the reliability test It turns out that falls.

  According to the present invention, it is possible to provide a photocurable resin composition having high viscosity stability and high adhesive strength and reliability. Further, by using the photocurable resin composition according to the present invention as a main sealant for a liquid crystal panel or an adhesive member for a CCD camera module, the reliability and yield of the product can be improved.

Claims (6)

  (A) a (meth) acryl compound having at least one (meth) acryl group in one molecule, (B) a photoinitiator, (C) an epoxy resin having at least one glycidyl group in one molecule, and (D ) A curable resin composition comprising a curing agent comprising an aminoalkylimidazole compound as an essential component. The curable resin composition according to claim 1, wherein the aminoalkylimidazole compound of component (D) is an aminoalkylimidazole compound represented by the general formula (1).
(Here, R is a hydrogen atom or a monovalent hydrocarbon group, R _{1 to} R ₃ are each independently a hydrogen atom or a hydrocarbon group which may have a substituent, and n is 2 or 3. )   The component (D) is an aminoalkylimidazole compound (d1) that is heat-treated together with a diamine compound (d2) having a cyclic structure, urea (d3), and an epoxy resin (d4) having an average of two glycidyl groups in the molecule. The curable resin composition according to claim 1, which is present in the form of a treated product.   The curable resin composition according to any one of claims 1 to 3, wherein the component (D) is present in an amount of 1 to 20 parts by weight per 100 parts by weight of the total of the components (A) and (C).   The component (A) is a partially esterified epoxy (meth) acrylic compound obtained by partially esterifying (meth) acrylic acid with an epoxy resin having at least two glycidyl groups in one molecule. 5. The curable resin composition according to any one of 4 above.   The sealing agent for bonding of the liquid crystal display device manufactured by the dripping method which consists of a curable resin composition of any one of Claims 1-5.