Resin composition for sealing material, and film liquid crystal panel sealed with said resin composition for sealing material

Abstract

This resin composition for a sealing material comprises (A) a polyfunctional thiol having 2-6 thiol groups, (B) a compound having 2-3 polymerizable unsaturated bonds, and (C) a crosslinking regulator. The (B) compound having 2-3 polymerizable unsaturated bonds contains (B1) a bifunctional urethane (meth)acrylate. The (C) crosslinking regulator is an amine compound that is solid at 25°C. The resin composition for a sealing material has high viscosity stability in an uncured state, and has, after being cured, high adhesion to a base material, cleaning liquid resistance, excellent light resistance, and the ability to suppress bleed-out under high temperature and high humidity conditions.

Description

Resin composition for sealing material, and film liquid crystal panel sealed with said resin composition for sealing material

[0001] The present invention relates to a resin composition for an encapsulant used in a film liquid crystal panel. Specifically, the present invention relates to a resin composition for an encapsulant that has high viscosity stability in an uncured state, and after curing, has high adhesion to a substrate, is resistant to cleaning solutions, has excellent light resistance, and can suppress bleed-out under high-temperature and high-humidity conditions. The present invention also relates to a film liquid crystal panel encapsulated with an encapsulant made of the resin composition for an encapsulant.

[0002] Liquid crystal panels are widely used for displaying images in various electronic devices, including televisions and smartphones. A liquid crystal panel typically comprises a pair of glass substrates with electrodes on their surfaces, a frame-shaped sealant sandwiched between them, and a liquid crystal layer sealed within the area surrounded by the sealant. The sealant is required to protect the electrodes and the liquid crystal layer from mechanical and chemical action.

[0003] While most conventional liquid crystal panels use a glass substrate, in recent years, liquid crystal panels using a lightweight and flexible film substrate (hereinafter referred to as film liquid crystal panels) have been developed. Furthermore, film liquid crystal panels are required to have a narrow frame that allows for a large image display area while minimizing installation space. To meet this demand for a narrow frame, encapsulants are required to have improved adhesion and durability.

[0004] Generally, a resin composition for an encapsulant is composed of an acrylic resin, which is a photocurable resin, and a clay mineral powder. However, in order to improve the adhesion and durability described above, a technique of blending various additives into the resin composition for an encapsulant has been proposed (Patent Document 1).

[0005] Furthermore, in the manufacture of liquid crystal panels, after forming a sealant and bonding the substrates together, liquid crystal adhering to the exterior of the liquid crystal panel may be washed away. In this case, the sealant is required to protect the interior of the liquid crystal panel from the cleaning solution. To meet the above-mentioned requirement for resistance to the cleaning solution, a technology has been proposed in which a sealing portion made of an acrylic resin, which is resistant to the cleaning solution, is provided around the periphery of a sealant made of an epoxy resin (Patent Document 2).

[0006] In addition, as the frame of the encapsulant becomes narrower, it is necessary to apply the encapsulant resin composition more precisely. However, in the production of liquid crystal panels, the production time can sometimes be extended due to production problems, etc., and if the viscosity stability of the encapsulant resin composition is low in this case, the viscosity gradually increases, which can easily cause uneven coating during application. For this reason, high viscosity stability is required for the encapsulant resin composition. Furthermore, since film liquid crystal panels are also used outdoors, high light resistance performance is also required for the encapsulant.

[0007] JP 2022-072999 A Patent No. 4609679

[0008] In recent years, film liquid crystal panels have been increasingly deployed in mobile and mobility applications due to their high portability. However, their portability means that they may be exposed to unexpected high temperatures and high humidity, and they are therefore required to be more durable in harsh high-temperature, high-humidity environments than conventional film liquid crystal panels. Similarly, improved durability is also required for encapsulants. However, with conventional film liquid crystal panels, water absorption into the encapsulant occurs over time under high-temperature, high-humidity conditions, causing components in the cured film to bleed out, raising concerns about poor alignment of the liquid crystal layer and adverse effects on peripheral components of the film liquid crystal panel. The resin composition for encapsulant described in Patent Document 1 had insufficient durability to high temperatures and humidity, and posed the problem of components bleeding out from the cured film.

[0009] Furthermore, in Patent Document 2, two or more sealing portions are provided, which causes a problem of a complicated manufacturing process. Furthermore, conventional acrylic resins have insufficient durability against cleaning solutions, which makes it necessary to increase the volume of the sealing portions, which is a problem that goes against the demand for narrower frame sizes for film liquid crystal panels.

[0010] In addition to the traditional challenges of viscosity stability, adhesion to the substrate, resistance to cleaning solutions, and light resistance, encapsulant technology is also required to suppress bleed-out, but achieving all of these properties simultaneously has not been easy.

[0011] An object of the present invention is to provide a resin composition for an encapsulant which has high viscosity stability in an uncured state, and after curing, has high adhesion to a substrate, is resistant to cleaning solutions, has excellent light resistance, and is capable of suppressing bleed-out under high-temperature and high-humidity conditions, and a film liquid crystal panel encapsulated using the resin composition for an encapsulant.

[0012] That is, the present invention relates to the following [1] to [3]. [1] An encapsulant resin composition containing (A) a polyfunctional thiol having 2 to 6 thiol groups, (B) a compound having 2 to 3 polymerizable unsaturated bonds, and (C) a crosslinking adjuster, wherein the component (B) contains (B1) a bifunctional urethane (meth)acrylate, and the component (C) is an amine compound that is solid at 25°C. [2] The encapsulant resin composition according to the above [1], wherein the component (B) contains (B2) a polyfunctional (meth)allyl compound. [3] A film liquid crystal panel encapsulated using the encapsulant resin composition according to the above [1] or [2].

[0013] The resin composition for an encapsulant of the present invention has high viscosity stability in an uncured state, and after curing, has high adhesion to a substrate, is resistant to cleaning solutions, has excellent light resistance, and can suppress bleed-out under high-temperature and high-humidity conditions. Although the details of the mechanism of action are partially unknown, it is presumed as follows.

[0014] Conventional resin compositions for encapsulants absorb water into the cured film under high-temperature and high-humidity conditions, causing components that are incompatible with water to bleed out. On the other hand, by using the (C) crosslinking regulator, the (C) crosslinking regulator acts as a hydrogen bond acceptor and provides excellent interaction sites with the S—H bonds of the thiol groups of the (A) polyfunctional thiol, which are hydrogen bond donors, and the N—H bonds of the (B1) urethane (meth)acrylate, and it is presumed that this makes it possible to retain the components inside the cured film and suppress bleed-out due to water absorption.

[0015] Furthermore, since the crosslinking regulator (C) is a solid at 25°C, it is uniformly dispersed in the blend of the polyfunctional thiol (A) and the urethane (meth)acrylate (B1) and is in an inactive state.

[0016] Furthermore, conventional encapsulant resin compositions tend to shrink in volume due to the curing reaction upon light irradiation, which generates internal stress and makes them more susceptible to peeling from the substrate. On the other hand, the (C) crosslinking regulator can adjust the formation density (crosslink density) of carbon-carbon bonds and thioether bonds, and is therefore presumed to be able to suppress volume shrinkage. As a result, a cured film with low internal stress is formed, and an encapsulant with excellent adhesion to the substrate is obtained.

[0017] Furthermore, when a cured film of the encapsulant resin composition comes into contact with a cleaning liquid, the (C) crosslinking regulator is fixed in a solid state in the cured film, and therefore it is presumed that the (C) crosslinking regulator inhibits the cleaning liquid from penetrating into the cured film and improves the cleaning liquid resistance.

[0018] Furthermore, it is presumed that the crosslinking regulator (C) is fixed in the cured product during the light resistance test, which prevents an increase in yellowness index (YI value).

[0019] The present invention provides a resin composition for an encapsulant, comprising (A) a polyfunctional thiol having 2 to 6 thiol groups, (B) a compound having 2 to 3 polymerizable unsaturated bonds, and (C) a crosslinking adjuster, wherein the (B) compound having 2 to 3 polymerizable unsaturated bonds contains at least (B1) a bifunctional urethane (meth)acrylate, and the (C) crosslinking adjuster is an amine compound that is solid at 25°C.

[0020] In the present invention, unless otherwise specified, the term "XX to XX" indicating a numerical range is a concept including the lower limit ("XX") and the upper limit ("XX"). In other words, it precisely means "not less than XX and not more than XX."

[0021] The present invention will be described in detail below. The resin composition for encapsulation of the present invention is used as an encapsulant for a film liquid crystal panel, and contains the following (A), (B), and (C) as essential components.

[0022] <(A) Polyfunctional Thiol> The (A) polyfunctional thiol may be any compound having 2 to 6 thiol groups per molecule. A single compound may be used alone, or two or more compounds may be used in combination. The inclusion of such a compound promotes a thiol-ene reaction with other components, enhancing adhesion to the substrate. Furthermore, the thioether bond formed has a more flexible bond angle than bonds between atoms such as C, O, and N, resulting in a highly flexible cured product and enhancing adhesion of the encapsulant to the substrate. Furthermore, cured products formed from thioether bonds have high bond angle flexibility and can be cured at a high density so that the atoms fill the gaps between the bonds. This provides a high moisture barrier and prevents an increase in water absorption even when subjected to a cleaning solution resistance test. The (A) polyfunctional thiol is preferably a compound represented by the following formula 1:

[0023] (wherein a is an integer of 2 to 6, and R １ is a divalent to hexavalent organic group having 10 to 60 carbon atoms.

[0024] In the formula, a is preferably an integer of 3 to 6 from the viewpoints of improving the barrier properties of the sealing material for film liquid crystal panels, providing excellent cleaning solution resistance, and suppressing bleed-out under high temperature and humidity conditions. If a in the formula is within this range, the curing shrinkage after curing is small, and a good cured product can be obtained without reducing adhesion to the substrate. Among these, it is most preferable that a in the formula is 6 from the viewpoint of excellent cleaning solution resistance. Furthermore, R １ From the same viewpoint, R is preferably trivalent to hexavalent. １ has 10 to 60 carbon atoms, preferably 10 to 45 carbon atoms, and more preferably 12 to 30 carbon atoms. １ When the number of carbon atoms is within this range, the crosslink density of the cured product of the encapsulant resin composition is sufficient, the encapsulant has excellent barrier properties and cleaning solution resistance, and bleed-out under high-temperature and high-humidity conditions can be suppressed.

[0025] The organic group is a group that contains C and may further contain at least one element selected from the group consisting of Si, N, P, O, and S. The organic group may be a polymer having repeating units. In addition, the organic group may contain, for example, a ketone group, an ester group, an ether group, a hydroxyl group, an amide group, a thioether group, an isocyanurate group, or a glycoluril group in its structure.

[0026] Specific examples of (A) polyfunctional thiols include ethylene glycol bis(3-mercaptopropionate), tetraethylene glycol bis(3-mercaptopropionate), dipentaerythritol hexakis(3-mercaptopropionate), trimethylolpropane tris(2-mercaptoacetate), trimethylolpropane tris(3-mercaptopropionate), trimethylolethane tris(2-mercaptoacetate), trimethylolethane tris(3-mercaptopropionate), pentaerythritol tetrakis(2-mercaptoacetate), pentaerythritol tetrakis(3-mercaptopropionate), and 1,2,3-tris(2-mercaptoethylthio)propionate. Examples of such alkyl acrylate copolymers include 1,2,3-tris(3-mercaptopropylthio)propane, 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane, 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,8-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, tetrakis(2-mercaptoethylthiomethyl)methane, tetrakis(3-mercaptopropylthiomethyl)methane, 1,3,5-tris(mercaptoethyleneoxy)benzene, and tris-[(3-mercaptopropionyloxy)ethyl]-isocyanurate.

[0027] Among the compounds represented by the above formula 1, preferred are polyfunctional thiols having a pentaerythritol skeleton, polyfunctional thiols having a dipentaerythritol skeleton, and polyfunctional thiols having an isocyanurate skeleton. Among these, preferred are pentaerythritol tetrakis(3-mercaptopropionate), dipentaerythritol hexakis(3-mercaptopropionate), and tris-[(3-mercaptopropionyloxy)-ethyl]-isocyanurate, from the viewpoints of achieving high adhesion to substrates after curing, excellent light resistance, and suppressing bleed-out under high-temperature and high-humidity conditions.

[0028] The polyfunctional thiol (A) may be a commercially available product or may be synthesized. Specifically, the polyfunctional thiol can be obtained by a known method of esterification of a polyhydric alcohol such as pentaerythritol with a mercapto group-containing carboxylic acid such as 3-mercaptopropionic acid.

[0029] <(B) Compound Having 2 or 3 Polymerizable Unsaturated Bonds> The (B) compound having 2 or 3 polymerizable unsaturated bonds preferably contains a compound having two polymerizable unsaturated bonds, from the viewpoint of providing a cured product with high flexibility and excellent adhesion to a substrate, and therefore contains at least (B1) a difunctional urethane (meth)acrylate.

[0030] In addition, in the resin composition for encapsulant of the present invention, the compound (B) having 2 to 3 polymerizable unsaturated bonds may further contain a polyfunctional (meth)allyl compound (B2), within the range not impairing the object of the present invention.

[0031] <(B1) Bifunctional Urethane (Meth)acrylate> The (B1) bifunctional urethane (meth)acrylate is not particularly limited as long as it has a urethane bond in the molecule. It is a compound having two (meth)acrylic groups, and the cured product of the encapsulant resin composition can have high flexibility and high adhesion to the substrate. The (B1) bifunctional urethane (meth)acrylate can be obtained by reacting a polyisocyanate compound, a polyol compound, and a (meth)acrylate compound having a hydroxyl group using a known method. Furthermore, when a polyol compound is not used, the cured product can be obtained by reacting a polyisocyanate compound and a (meth)acrylate compound having a hydroxyl group using a known method. The (B1) bifunctional urethane (meth)acrylate can be used alone or in combination with two or more types. The urethane groups contained in such compounds can exhibit strong interactions, such as hydrogen bonds, between the urethane groups and with other polar groups. Furthermore, because the hydrogen bonds are more flexible than covalent bonds, the cured product of the encapsulant resin composition can maintain flexibility.

[0032] The polyisocyanate compound may be a known compound. Examples include aliphatic polyisocyanates, alicyclic polyisocyanates, and aromatic polyisocyanates. More specifically, examples include aliphatic polyisocyanates such as pentamethylene diisocyanate, hexamethylene diisocyanate, and trimethylhexamethylene diisocyanate; alicyclic polyisocyanates such as isophorone diisocyanate, hydrogenated diphenyl diisocyanate, and norbornene diisocyanate; aromatic polyisocyanates such as xylylene diisocyanate, tolylene diisocyanate, and diphenylmethane diisocyanate; and isocyanuric skeleton-containing triisocyanates, which are diisocyanate trimers. Among these, divalent diisocyanate compounds are preferred from the viewpoints of achieving high flexibility and excellent adhesion to substrates in the cured product of the encapsulant resin composition.

[0033] The polyol compound may be a known compound. Specific examples include polyester polyols, polyether polyols, polycarbonate polyols, and hydrocarbon polyols. Among these, polyester polyols and polycarbonate polyols are more preferred from the viewpoints of excellent adhesion to substrates and suppression of bleed-out under high-temperature and high-humidity conditions. The polyol compound is preferably a divalent diol compound from the viewpoint of flexibility of the urethane (meth)acrylate compound obtained after the reaction.

[0034] The polyester polyol may be a compound obtained by condensation reaction of a dicarboxylic acid compound and a polyol compound. Alternatively, a polyester polyol may be obtained by ring-opening addition polymerization of a cyclic ester with a dihydroxycarboxylic acid in the presence of a basic compound. Specific examples of the dicarboxylic acid compound include succinic acid, adipic acid, pimelic acid, and sebacic acid. Among these, adipic acid and pimelic acid are preferred. Examples of the polyol compound include diol compounds and triol compounds. Specific examples of the diol compound include ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, diethylene glycol, and dipropylene glycol. Specific examples of the triol compound include glycerin, 1,2,4-butanetriol, and trimethylolpropane. Among these, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, and diethylene glycol are preferred from the viewpoint of adhesion to the substrate.

[0035] The cyclic esters may usually be composed of lactones. Specific examples of lactones (and cyclic monoesters) include β-propiolactone, β-butyrolactone, γ-butyrolactone, δ-valerolactone, δ-caprolactone, ε-caprolactone, γ-valerolactone, γ-caprolactone, γ-caprylolactone, γ-laurolactone, enantholactone, dodecanolactone, stearolactone, and alkyl-ε-caprolactone, and are preferably lactones having 3 to 20 carbon atoms, more preferably lactones having 4 to 15 carbon atoms.

[0036] The polyether polyol may be a known compound. Specific examples include diol compounds such as polyethylene glycol, polypropylene glycol, polybutylene glycol, and polytetramethylene glycol, and triol compounds such as polyoxypropylene triol and polyoxyethylene polyoxypropylene triol. Among these, polyethylene glycol and polypropylene glycol are preferred from the viewpoint of adhesion to the substrate.

[0037] The polycarbonate polyol may be a compound obtained by transesterification of a carbonate diester with a polyol compound. Specific examples of carbonate diesters include diphenyl carbonate, dimethyl carbonate, and diethylene carbonate. Among these, diethylene carbonate is preferred. Specific examples of polyol compounds include diol compounds and triol compounds. Specific examples of diol compounds include ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, diethylene glycol, and dipropylene glycol. Specific examples of triol compounds include glycerin, 1,2,4-butanetriol, and trimethylolpropane. Among these, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, and diethylene glycol are preferred from the viewpoint of adhesion to the substrate.

[0038] Known compounds can be used as the hydrocarbon polyol, and specific examples of hydrocarbon polyols include diol compounds such as ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, and 1,8-octanediol, and triol compounds such as glycerin, 1,2,4-butanetriol, and trimethylolpropane.

[0039] The (meth)acrylate compound having a hydroxyl group can be a known compound. Specific examples include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 4-hydroxycyclohexyl (meth)acrylate, 5-hydroxycyclooctyl (meth)acrylate, 2-hydroxy-3-phenyloxypropyl (meth)acrylate, propylene glycol monoacrylate, polyethylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, and polycaprolactone mono(meth)acrylate. Among these, 2-hydroxyethyl (meth)acrylate, propylene glycol mono(meth)acrylate, and polycaprolactone mono(meth)acrylate are more preferred from the viewpoint of suppressing bleed-out under high-temperature and high-humidity conditions, and 2-hydroxyethyl acrylate, propylene glycol monoacrylate, and polycaprolactone monoacrylate, which can introduce an acrylate group into the molecular terminal of a urethane (meth)acrylate, are even more preferred.

[0040] The weight-average molecular weight of the (B1) bifunctional urethane (meth)acrylate compound is preferably 1,300 or more, more preferably 3,000 or more, from the viewpoint of excellent viscosity stability. Furthermore, from the viewpoint of maintaining cleaning solution resistance, it is preferably 20,000 or less, more preferably 12,500 or less. That is, in order for the encapsulant resin composition to have high viscosity stability in the uncured state and excellent cleaning solution resistance after curing, the weight-average molecular weight of the (B1) bifunctional urethane (meth)acrylate compound is preferably 1,300 to 20,000, more preferably 3,000 to 12,500. The weight-average molecular weight of the (B1) bifunctional urethane (meth)acrylate compound is determined by gel permeation chromatography (GPC) using a standard polystyrene calibration curve.

[0041] In the compound (B) having 2 to 3 polymerizable unsaturated bonds, the content of the difunctional urethane (meth)acrylate (B1) is preferably 10% by mass or more, and more preferably 20% by mass or more.

[0042] <(B2) Polyfunctional (meth)allyl Compound> When the polyfunctional (meth)allyl compound (B2) is used in combination with (B1), it forms a thioether bond through a thiol-ene reaction with the polythiol compound (A), thereby improving adhesion and cleaning solution resistance while maintaining the flexibility of the cured product of the encapsulant resin composition, and obtaining a cured product with a low yellowness index (YI value). The polyfunctional (meth)allyl compound (B2) is a compound having 2 to 3 (meth)allyl groups, and from the viewpoints of achieving high flexibility and excellent adhesion to substrates in the cured product, a compound having two (meth)allyl groups is preferred.

[0043] Specific examples of the polyfunctional (meth)allyl compound (B2) include 1,4-cyclohexanedicarboxylic acid di(meth)allyl ester, isophthalic acid di(meth)allyl ester, phthalic acid di(meth)allyl ester, hexahydrophthalic acid di(meth)allyl ester, di(meth)allyl methylglycidyl isocyanurate, magnolol, di(meth)allyldiphenylsilane, trimethylolpropane di(meth)allyl ether, 2,2'-bis(3-(meth)allyl-4-hydroxyphenyl)propane, 2,2-bis(3-(meth)allyl-4-allyloxyphenyl)propane, Examples of suitable (meth)allyl compounds include 2,2-bis(3-(meth)allyl-4-glycidyloxyphenyl)propane, 1,3-diallyl-5-propyl isocyanurate, 1,3-di(meth)allyl-5-glycidyl isocyanurate, 1,3-di(meth)allyl cyanurate, 1,3-di(meth)allyl glycoluril, 1,3-di(meth)allyl-4,6-bis(methoxymethyl)glycoluril, tri(meth)allyl isocyanurate, pentaerythritol tri(meth)allyl ether, glycerin tri(meth)allyl ether, and trimethylolpropane tri(meth)allyl ether. Among the above (meth)allyl compounds, compounds having two (meth)allyl groups, such as phthalic acid diallyl ester, 1,3-diallyl-5-glycidyl isocyanurate, and 1,3-diallyl-5-propyl isocyanurate, are preferred from the viewpoint of achieving high flexibility and excellent adhesion to substrates in a cured product.

[0044] The polyfunctional (meth)allyl compound (B2) may be used alone or in combination of two or more kinds.

[0045] When the polyfunctional (meth)allyl compound (B2) is used, the content of the polyfunctional (meth)allyl compound (B2) in the compound (B) having 2 to 3 polymerizable unsaturated bonds is preferably 80 mass% or less.

[0046] <(C) Crosslinking Regulator> The (C) crosslinking regulator may be any amine compound that is solid at 25° C., and one type may be used alone, or two or more types may be used in combination. By including such a compound, the composition after curing can have high adhesion to substrates, cleaning solution resistance, and excellent light fastness, and can suppress bleeding out under high-temperature and high-humidity conditions.

[0047] Specific examples of the amine compound include imidazole-type adducts and aliphatic amine compounds made from imidazole as a raw material, and amine-type adducts made from aromatic amine compounds as raw materials, and the amine-type adducts are preferred from the viewpoint of excellent resistance to cleaning solutions.

[0048] [Imidazole Adduct] The imidazole adduct is a reaction product of an imidazole compound and an epoxy resin, or a reaction product of an imidazole compound and an isocyanate compound, and also includes reaction products whose surfaces are treated with an isocyanate compound or an acidic compound such as a phenol resin. From the viewpoint of excellent cleaning solution resistance, a reaction product of an imidazole compound and an epoxy is preferred.

[0049] Examples of imidazole compounds that can be used as raw materials for forming the imidazole adduct include 2-ethyl-4-methylimidazole, 2-methylimidazole, 1-(2-hydroxy-3-phenoxypropyl)-2-methylimidazole, 1-(2-hydroxy-3-phenoxypropyl)-2-ethyl-4-methylimidazole, 1-(2-hydroxy-3-butoxypropyl)-2-methylimidazole, 1-(2-hydroxy-3-butoxypropyl)-2-ethyl-4-methylimidazole, etc. In the present invention, the imidazole compound also includes imidazoline compounds in which the double bond of the imidazole ring is hydrogenated. Examples of such imidazoline compounds include 2-ethyl-4-methylimidazoline, 2,4-dimethylimidazoline, 1-(2-hydroxy-3-phenoxypropyl)-2-phenylimidazoline, and 1-(2-hydroxy-3-butoxypropyl)-2-methylimidazoline.

[0050] Specific examples of commercially available crosslinking regulators that are imidazole adducts include Amicure PN-23, Amicure PN-23J, Amicure PN-31, Amicure PN-31J, Amicure PN-40, Amicure PN-40J, Amicure PN-H (all manufactured by Ajinomoto Fine-Techno Co., Ltd.), ADEKA Hardener EH-3293S, ADEKA Hardener EH-5011S, ADEKA Hardener EH-5019S, ADEKA Hardener EH-5046S (all manufactured by ADEKA Corporation), Fujicure FXR-1020, Fujicure FXR-1130, Fujicure FXR-1121 (all manufactured by T&K TOKA Corporation), and the like.

[0051] [Amine Adduct] The amine adduct is a reaction product of an aliphatic amine compound or an aromatic amine compound with an epoxy resin, or a reaction product of an aliphatic amine compound or an aromatic amine compound with an isocyanate compound, and also includes reaction products of these reaction products whose surfaces are treated with an isocyanate compound or with an acidic compound such as a phenol resin. From the viewpoint of excellent resistance to cleaning solutions, reaction products of an aliphatic amine compound or an aromatic amine compound with an epoxy are preferred.

[0052] The amine compound used as a raw material for forming the amine adduct can be appropriately selected from aliphatic amine compounds and aromatic amine compounds known as curing agents for epoxy resins. Examples of the aliphatic amine compound include ethylenediamine, propylenediamine, butylenediamine, hexamethylenediamine, diethylenetriamine, dipropylenetriamine, dibutylenetriamine, triethylenetetramine, tripropylenetetramine, tributylenetetramine, tetraethylenepentamine, tetrapropylenepentamine, tetrabutylenepentamine, N,N'-dimethylethylenediamine, pentaethylenehexamine, isophoronediamine, menthanediamine, piperazine, 1-aminoethylpiperazine, monomethylamine, methylaminopropanol ... Examples of the aromatic amine compounds include phenylenediamine, 4-aminodiphenylamine, 3,5-diaminochlorobenzene, melamine, aminophenyl ether, etc. Among these, from the viewpoint of suppressing bleed-out under high-temperature and high-humidity conditions, aliphatic amine compounds are preferred, and specifically, propylenediamine, isophoronediamine, and 1,3-bisaminocyclohexane are preferred.

[0053] Examples of epoxy resins that can be used as raw materials for forming the imidazole adduct and the amine adduct include polyglycidyl aromatic ethers obtained by reacting polyhydric phenols such as bisphenol A, bisphenol F, and resorcinol with epichlorohydrin; polyglycidyl aliphatic ethers obtained by reacting polyhydric alcohols such as glycerin and polyethylene glycol with epichlorohydrin; glycidyl ether esters obtained by reacting hydroxycarboxylic acids such as p-hydroxybenzoic acid with epichlorohydrin; polyglycidyl esters obtained by reacting polycarboxylic acids such as phthalic acid and terephthalic acid with epichlorohydrin; glycidyl amine compounds obtained by reacting 4,4'-diaminodiphenylmethane, m-aminophenol, or the like with epichlorohydrin; polyfunctional epoxy compounds such as epoxidized phenol novolac resins, epoxidized cresol novolac resins, and epoxidized polyolefins; and monofunctional epoxy compounds such as butyl glycidyl ether, phenyl glycidyl ether, and glycidyl methacrylate.

[0054] Examples of the isocyanate compound that serves as a raw material for forming the imidazole-type adduct and the amine-type adduct include monofunctional isocyanate compounds such as butyl isocyanate, isopropyl isocyanate, phenyl isocyanate, and benzyl isocyanate; polyfunctional isocyanate compounds such as hexamethylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,5-naphthalene diisocyanate, diphenylmethane-4,4'-diisocyanate, isophorone diisocyanate, xylylene diisocyanate, paraphenylene diisocyanate, 1,3,6-hexamethylene triisocyanate, and bicycloheptane triisocyanate; and terminal isocyanate group-containing compounds obtained by reacting these polyfunctional isocyanate compounds with active hydrogen compounds. Examples of such a terminal isocyanate group-containing compound include an addition compound having a terminal isocyanate group obtained by reacting tolylene diisocyanate with trimethylolpropane, and an addition compound having a terminal isocyanate group obtained by reacting tolylene diisocyanate with pentaerythritol.

[0055] Examples of acidic compounds for surface treatment of the imidazole adduct and the amine adduct include phenolic resins, polyhydric phenol compounds, polycarboxylic acids, etc. Phenolic resins are synthesized from phenols and aldehydes, and examples thereof include phenol / formalin resin, cresol / formalin resin, bisphenol A (BPA) / formalin resin, bisphenol F (BPF) / formalin resin, alkylphenol / formalin resin, and mixtures thereof.

[0056] Examples of the polyhydric phenol compound include bisphenol A, bisphenol F, and resorcinol.

[0057] Examples of the polycarboxylic acids include dicarboxylic acids such as adipic acid, sebacic acid, dodecanedioic acid, and azelaic acid.

[0058] When a phenolic resin and a polyhydric phenolic compound are used as the acidic compound, the amount of the phenolic resin and the polyhydric phenolic compound is preferably 1.0 to 40.0 parts by mass, more preferably 3.0 to 25.0 parts by mass, and even more preferably 5.0 to 15.0 parts by mass or less, relative to 100.0 parts by mass of the imidazole adduct and the amine adduct.

[0059] When polycarboxylic acids are used as the acidic compound, the amount of the polycarboxylic acids is preferably 1.0 to 15.0 parts by mass, more preferably 2.0 to 10.0 parts by mass, and even more preferably 3.0 to 8.0 parts by mass, per 100.0 parts by mass of the imidazole adduct and the amine adduct.

[0060] The reaction of the imidazole adduct and the amine adduct with the acidic compound is carried out at 80 to 200° C. for 30 minutes to 5 hours.

[0061] Specific examples of commercially available crosslinking regulators that are amine-type adducts include ADEKA HARDNER EH-4357S, ADEKA HARDNER EH-5030S, ADEKA HARDNER EH-5057P, and ADEKA HARDNER EH-5057PK (all manufactured by ADEKA Corporation).

[0062] The (C) crosslinking regulator can be obtained by reacting the raw materials using a known method. For example, the raw materials can be stirred and reacted at 80 to 200°C, followed by cooling and pulverizing the solid content. Alternatively, a solvent can be used, and the raw materials can be reacted in a solvent such as methyl ethyl ketone, dioxane, tetrahydrofuran, or xylene, and the solvent can be removed, followed by pulverizing the solid content.

[0063] From the viewpoint of excellent cleaning solution resistance, the melting point of the (C) crosslinking modifier is 50 to 180°C, more preferably 75 to 150°C. The shape is not particularly specified, but is preferably spherical. The melting point can be measured in accordance with JIS K0064:1992, "Method for measuring the melting point and melting range of chemical products (visual method)," using a commercially available melting point measuring device such as the M-565 melting point measuring device manufactured by Shibata Scientific Products Co., Ltd. Specifically, a capillary tube for measuring melting point filled with a sample of the (C) crosslinking modifier or the like was placed in the M-565 melting point measuring device, and the melting point was measured at a heating rate of 1°C / min. The melting point was measured as the temperature at which the sample melted in the capillary and was completely liquefied. If the sample did not clearly melt, the temperature was measured from the temperature at which the sample began to soften and deform until it gathered at the tip of the capillary.

[0064] The average particle size of the (C) crosslinking regulator is preferably 30 μm or less, more preferably 15 μm or less, and even more preferably 5 μm or less, from the viewpoints of maintaining adhesion to the substrate, excellent cleaning solution resistance, and suppressing bleed-out under high-temperature and high-humidity conditions. Furthermore, from the viewpoints of excellent viscosity stability and light resistance, the average particle size is preferably 0.5 μm or more, more preferably 1 μm or more, and even more preferably 2 μm or more.

[0065] That is, in order for the resin composition for an encapsulant to have high viscosity stability in an uncured state, maintain adhesion to a substrate after curing, have excellent cleaning solution resistance, and be able to suppress bleed-out under high-temperature and high-humidity conditions, the average particle size of the crosslinking regulator (C) is 0.5 μm to 30 μm, more preferably 1 μm to 15 μm, and even more preferably 2 μm to 5 μm.

[0066] The average particle size can be measured using a commercially available laser diffraction particle size distribution analyzer such as the Microtrac MT-3300II manufactured by Microtrac Bell Corporation. Specifically, 0.1 to 0.5 g of (C) crosslinking modifier and 30 g of ethanol were weighed into a beaker and pre-dispersed using an ultrasonic disperser. This was used as a sample for particle size measurement. The ultrasonic dispersion used for pre-dispersion is preferably performed under constant conditions. A US-300T ultrasonic disperser (manufactured by Nippon Seiki Seisakusho Co., Ltd.) was used as the ultrasonic disperser, and pre-dispersion was performed under constant conditions for 60 seconds at a current value of 300 μA. The laser diffraction particle size distribution analyzer used was the Microtrac MT-3300II. The entire process from sample preparation to measurement of the prepared sample was completed within 5 minutes, and the value at 50% of the cumulative average diameter displayed as the measurement result was taken as the average particle size (D50).

[0067] <(D) Photopolymerization initiator> The (D) photopolymerization initiator is added to promote the photocuring reaction of the (A) polyfunctional thiol and the (B1) urethane (meth)acrylate, and can reduce the amount of light irradiation required to cure the encapsulant resin composition. The (D) photopolymerization initiator can be used alone or in combination of two or more. Examples of photopolymerization initiators include photoradical polymerization initiators, photocationic polymerization initiators, and photoanionic polymerization initiators. Among these, photoradical polymerization initiators are preferred from the viewpoint of excellent light resistance.

[0068] Specific examples of the photoradical polymerization initiator include 2,2-dimethoxy-1,2-diphenylethan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]-phenyl}-2-methyl-propan-1-one, and 2-methyl -1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, 1,2-octanedione-1-[4-(phenylthio)phenyl]-2-(O-benzoyloxime), 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3yl]ethanone-1-(O-acetyloxime), and the like.

[0069] Specific examples of the photocationic polymerization initiator include bis(4-tert-butylphenyl)iodonium hexafluorophosphate, bis(4-tert-butylphenyl)iodonium trifluoromethanesulfonate, cyclopropyldiphenylsulfonium tetrafluoroborate, diphenyliodonium hexafluorophosphate, diphenyliodonium hexafluoroarsenate, 2-(3,4-dimethoxystyryl)-4,6-bis(trichloromethyl)-1,3,5-triazine, triphenylsulfonium tetrafluoroborate, triphenylsulfonium bromide, tri-p-tolylsulfonium hexafluorophosphate, and tri-p-tolylsulfonium trifluoromethanesulfonate.

[0070] Specific examples of the photoanionic polymerization initiator include acetophenone o-benzoyloxime, nifedipine, 2-(9-oxoxanthen-2-yl)propionic acid 1,5,7-triazabicyclo[4,4,0]dec-5-ene, 2-nitrophenylmethyl 4-methacryloyloxypiperidine-1-carboxylate, 1,2-diisopropyl-3-[bis(dimethylamino)methylene]guanidinium 2-(3-benzoylphenyl)propionate, and 1,2-dicyclohexyl-4,4,5,5-tetramethylbiguanidinium n-butyltriphenylborate.

[0071] <Other Components> The resin composition for encapsulant of the present invention may contain additives such as a surfactant, a silane coupling agent, a curing accelerator, an ultraviolet absorber, a light stabilizer, an antioxidant, a polymerization inhibitor, a leveling agent, an adhesion promoter, a plasticizer, an antifoaming agent, a light-shielding material, a conductive material, and a spacer, as long as the additives do not impair the object of the present invention.

[0072] <Composition Ratio> From the viewpoint of excellent viscosity stability and light resistance, the content of the crosslinking adjuster (C) in the resin composition for encapsulant of the present invention is preferably 30.0 parts by mass or less, more preferably 15.0 parts by mass or less, and even more preferably 10.0 parts by mass or less, relative to 100 parts by mass of the total of (A) and (B).

[0073] Furthermore, from the viewpoints of achieving excellent cleaning solution resistance and suppressing bleed-out under high-temperature and high-humidity conditions, the amount of the crosslinking regulator (C) is preferably 0.005 parts by mass or more, more preferably 0.01 parts by mass or more, and even more preferably 0.1 parts by mass or more, per 100 parts by mass of the total of (A) and (B).

[0074] In order for the resin composition for an encapsulant of the present invention to have high adhesion to a substrate after curing, excellent cleaning solution resistance, and be able to suppress bleed-out under high-temperature and high-humidity conditions, the ratio of the amount of thiol groups in (A) the polyfunctional thiol to the amount of polymerizable unsaturated bonds in (B) the compound having 2 to 3 polymerizable unsaturated bonds (amount of thiol groups / amount of polymerizable unsaturated bonds) is preferably 0.5 to 6.0, and more preferably 1.0 to 4.5.

[0075] <Film Liquid Crystal Panel> The film liquid crystal panel of the present invention includes, for example, a light control element that simply controls transparency and opacity by the alignment of liquid crystals, and a display element that displays images like a display. The film liquid crystal panel of the present invention includes, for example, a pair of substrates arranged opposite each other, the periphery of which is sealed with the above-mentioned encapsulant resin composition, and a liquid crystal material present between them. Here, the substrate is a plastic transparent film substrate such as polyethylene terephthalate, polycarbonate, cycloolefin (co)polymer, acrylic resin, methacrylic resin (PMMA), or polyimide, on which a silver or copper electrode and a transparent electrode such as indium tin oxide (ITO) or poly(3,4-ethylenedioxythiophene) (PEDOT) are provided. Also included are those in which an alignment film or the like is further formed on the transparent electrode.

[0076] The film liquid crystal panel of the present invention is a liquid crystal panel formed from the above-mentioned plastic transparent film substrate, and the resin composition for a sealant is used as a sealant for the above-mentioned film liquid crystal panel.

[0077] <Formation of Film Liquid Crystal Panel> The film liquid crystal panel of the present invention is formed by applying the encapsulant resin composition of the present invention to one of the pair of substrates, dropping liquid crystal on the inner side of the applied resin composition, overlaying the other substrate, irradiating with light and curing the encapsulant resin composition. Alternatively, the film liquid crystal panel of the present invention can be formed by applying a polymer dispersed liquid crystal containing liquid crystal and the encapsulant resin composition to one of the pair of substrates, overlaying the other substrate, irradiating with light to cure the polymer dispersed liquid crystal, and then applying the encapsulant resin composition of the present invention to the outer periphery and curing it with light.

[0078] The method for applying the resin composition for encapsulant is not particularly limited, and examples thereof include a method using coating equipment such as dispenser coating, inkjet method, or screen printing method, and a method of hand-applying with a syringe or a brush.

[0079] The light source for irradiating the resin composition for an encapsulant with light is not particularly limited, and examples thereof include mercury lamps such as high-pressure mercury lamps and ultra-high-pressure mercury lamps, black light lamps, LED lamps, halogen lamps, electrodeless lamps, xenon lamps, mercury fluorescent lamps, LED fluorescent lamps, sunlight, and electron beam irradiation devices.

[0080] Next, the present invention will be described more specifically with reference to examples and comparative examples.

[0081] <Evaluation Method> The performance of the encapsulant resin composition in each of the Examples and Comparative Examples was evaluated by the following methods.

[0082] <Viscosity Stability> Viscosity stability was evaluated based on the viscosity increase after the encapsulant resin composition was placed in a thermo-hygrostat chamber at 25°C / 55% RH. The viscosity was measured using an RE80 viscometer (manufactured by Toki Sangyo Co., Ltd., cone rotor: 3° x R9.7) after rotating the encapsulant resin composition (0.25 to 0.50 mL) at 1.0 rpm for 120 seconds (unit: Pa s). The viscosity increase rate was calculated from the obtained results using the following formula: ((viscosity after storage) / (initial viscosity)-1) x 100 = viscosity increase rate (%). The time required for the viscosity increase rate from the initial viscosity to exceed 50% was evaluated. The longer the time required for the viscosity increase rate from the initial viscosity to exceed 50%, the better the viscosity stability. ⊚: 72 hours or more ◯: 24 hours or more ×: Less than 24 hours

[0083] <Bleeding out> Bleeding out was carried out by applying the encapsulant resin composition to a glass substrate ("MICRO SLIDE GLASS S9110" manufactured by Matsunami Glass Industrial Co., Ltd.) with an applicator to a thickness of 100 μm, and then irradiating the encapsulant resin composition with a high-pressure mercury lamp (illuminance in terms of i-line: 100 mW / cm ２ ) for 30 seconds (integrated light amount: 3000 mJ / cm ２) to obtain a cured test piece. The obtained test piece was subjected to a pressure cooker test at 120°C, 80% RH, and 200 kPa for 200 hours. The appearance of the cured film surface after the test was observed using an optical microscope at a magnification of 200 times, in a field of view of 70 μm × 70 μm, and evaluated according to the following criteria. Note that if the evaluation is ◯ or higher, there is no problem in practical use, and if the evaluation is ⊚, it is more preferable. ⊚: No change from the initial state ⊚: Unevenness is visible in parts ⊚: Unevenness is visible overall

[0084] <Adhesion> The resin composition for an encapsulant was applied to one of two polycarbonate films (PC-1600 (transparent), 2.0 mm thick, 25 mm × 100 mm, manufactured by Takiron C.I. Co., Ltd.) using a screen printer, and the other polycarbonate film was placed on the other polycarbonate film with an overlapping length of 10 mm (adhesion area of ​​250 mm). ２ The resin composition for an encapsulant sandwiched between two polycarbonate films was irradiated with a high-pressure mercury lamp (illuminance in i-line equivalent: 100 mW / cm ２ ) for 30 seconds (integrated light amount: 3000 mJ / cm ２ ) to cure the resin composition for encapsulant, thereby obtaining a test piece. The tensile shear strength of the obtained test piece was measured in accordance with JIS-K-6850 using a tensile tester (Autograph AG-IS manufactured by Shimadzu Corporation) (measurement environment: temperature 25°C, tensile speed: 10 mm / min). From the obtained results, the initial tensile shear strength A was calculated using the following formula: (Formula): Tensile shear strength A (N / mm ２ )=Maximum load (N) / Adhesive area (mm ２ ) ◎: 10N / mm ２ Peeling occurs at 5 N / mm or more. ２ Above, 10N / mm ２ Peeling occurs at less than 5 N / mm. ２ It peels off in less than

[0085] <Cleaning Solution Resistance> A separate test specimen was prepared using the same procedure as in the evaluation of the initial tensile shear strength A. The obtained test specimen was immersed in a beaker containing a 1 mol / L hydrochloric acid aqueous solution (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) whose temperature was adjusted to 40°C. After 1 hour, the test specimen was removed from the hydrochloric acid aqueous solution, washed with pure water, and then air-dried. The tensile shear strength of the dried test specimen was measured in accordance with JIS-K-6850 using a tensile tester (Autograph AG-IS manufactured by Shimadzu Corporation) (measurement environment: temperature 25°C, tensile speed: 10 mm / min). The tensile shear strength B was calculated from the obtained results using the following formula. It can be said that the larger the value of tensile shear strength B, the better the cleaning solution resistance of the test specimen. (Formula): Tensile shear strength B (N / mm ２ )=Maximum load (N) / Adhesive area (mm ２ ) ◎: 10N / mm ２ Peeling occurs at 5 N / mm or more. ２ Above, 10N / mm ２ Peeling occurs at less than 5 N / mm. ２ It peels off in less than

[0086] <Initial Yellowness Index (YI Value)> The yellowness index was measured by applying the resin composition for encapsulant to a thickness of 100 μm on a glass substrate (MICRO SLIDE GLASS S9110, thickness 0.9 mm, 50 mm × 50 mm, manufactured by Matsunami Glass Industrial Co., Ltd.) using an applicator, and then illuminating the resin composition for encapsulant with a high-pressure mercury lamp (illuminance in terms of i-line: 100 mW / cm ２ ) for 30 seconds (integrated light amount: 3000 mJ / cm ２ ) to obtain a cured test piece. Using a spectrophotometer ("SPECTROPHOTO METER CM-5", manufactured by Konica Minolta, Inc., light source: D65), the initial yellowness index (YI value) was measured in accordance with JIS-K-7373:2006 "Plastics - Determination of yellowness index and yellowing index". The evaluation criteria for the initial yellowness index (YI value) are as follows. The smaller the YI value, the better. ◎: YI value less than 6.0 ○: YI value 6.0 or more but less than 10.0 ×: YI value 10.0 or more

[0087] <Lightfastness> For lightfastness, the test specimens evaluated for the initial yellowness index (YI value) were used. The test specimens were placed in a Super Xenon Weather Meter (SX75 model, manufactured by Suga Test Instruments Co., Ltd.) and heated for 500 hours (78.5 W / m ２ The test was carried out (black panel temperature 63°C), and the yellowness index (YI value) after the test was measured using the spectrophotometer (light source: D65) in accordance with JIS-K-7373:2006 "Plastics - Determination of yellowness index and yellowing index". The yellowing index (ΔYI value) was calculated from the obtained results using the following formula: (Formula): Yellowness index after test (YI value) - Initial yellowness index (YI value) = Yellowing index (ΔYI value) The evaluation criteria for lightfastness are as follows. The smaller the ΔYI value, the better the lightfastness. ◎: ΔYI value less than 5.0 ○: ΔYI value 5.0 or more but less than 10.0 ×: ΔYI value 10.0 or more

[0088] <Synthesis of Urethane (Meth)acrylate Compound> (Production of Diol Compound (b-1): Raw Material 1 for Urethane (Meth)acrylate Compound (B1-1)) 1,000 g of adipic acid and 1,074 g of 3-methyl-1,5-pentanediol were charged into a reaction vessel equipped with a stirrer, a rectification column, a nitrogen inlet tube, and a thermometer, and the mixture was heated to 140°C under a nitrogen atmosphere and stirred. 0.07 g of tetrabutyl titanate was charged thereto, and the mixture was heated to 220°C to carry out a dehydration reaction. Thereafter, the mixture was held at 220°C to carry out a dehydration reaction. 18 hours after the start of the dehydration reaction, the contents were cooled to obtain 2,000 g of diol compound (b-1) (weight average molecular weight: 1,600).

[0089] (Production of diol compound (b-2): Raw material 2 for urethane (meth)acrylate compound (B1-2)) A reaction vessel equipped with a stirrer, a rectification column, a nitrogen inlet tube, and a thermometer was charged with 1,000 g of diethylene carbonate, 1,059 g of 1,6-hexanediol, and 0.06 g of tetraisopropyl titanate, and the reaction was carried out while refluxing the diethylene carbonate in a nitrogen atmosphere under normal pressure and distilling off the produced ethanol together with the diethylene carbonate to the outside of the system. From the point at which the amount of ethanol distilled off decreased, the temperature was gradually raised, and when the temperature reached 200°C and the distillation of ethanol stopped, the system was allowed to cool. The pressure was reduced with a vacuum pump, and the excess diol component was distilled off while heating again, yielding 2,000 g of diol compound (b-2) (weight average molecular weight: 2,100).

[0090] (Production of diol compound (b-3): Raw material 3 for urethane (meth)acrylate compound (B1-3)) 1,000 g of adipic acid and 1,401 g of 1,6-hexanediol were charged into a reaction vessel equipped with a stirrer, a rectification column, a nitrogen inlet tube, and a thermometer, and the mixture was heated to 140°C under a nitrogen atmosphere and stirred. 0.07 g of tetrabutyl titanate was charged thereto, and the mixture was heated to 220°C to carry out a dehydration reaction. Thereafter, the mixture was held at 220°C to carry out a dehydration reaction. 6 hours after the start of the dehydration reaction, the contents were cooled to obtain 2,350 g of diol compound (b-3) (weight average molecular weight: 800).

[0091] (Production of diol compound (b-4): Raw material 4 for urethane (meth)acrylate compound (B1-4)) 1,000 g of pimelic acid and 1,275 g of 3-methyl-1,5-pentanediol were charged into a reaction vessel equipped with a stirrer, a rectification column, a nitrogen inlet tube, and a thermometer, and the mixture was heated to 140°C under a nitrogen atmosphere and stirred. 0.06 g of tetrabutyl titanate was charged thereto, and the mixture was heated to 220°C to carry out a dehydration reaction. Thereafter, the mixture was held at 220°C to carry out a dehydration reaction. 18 hours after the start of the dehydration reaction, the contents were cooled to obtain 2,200 g of diol compound (b-4) (weight average molecular weight: 1,750).

[0092] (Production of diol compound (b-5): raw material 5 for urethane (meth)acrylate compound (B1-6)) 1,000 g of pimelic acid and 1,729 g parts by mass of 2,4-diethyl-1,5-pentanediol were charged into a reaction vessel equipped with a stirrer, a distillation column, a nitrogen inlet tube, and a thermometer, and the mixture was heated to 140°C under a nitrogen atmosphere and stirred. 0.06 g of tetrabutyl titanate was charged thereto, and the mixture was heated to 220°C to carry out a dehydration reaction. Thereafter, the mixture was held at 220°C to carry out a dehydration reaction. 18 hours after the start of the dehydration reaction, the contents were cooled to obtain 2,700 g of diol compound (b-5) (weight average molecular weight: 3,000).

[0093] (Production of Urethane (Meth)acrylate Compound (B1-1)) A reaction vessel equipped with a stirrer, a reflux condenser, a nitrogen inlet tube, and a thermometer was charged with 1,000 g of the diol compound (b-1) obtained above, and stirring was initiated. Next, 0.6 g of dibutyltin laurate and 278 g of 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate as a polyisocyanate compound were added to (b-1), and the internal temperature was raised to 80°C while taking care to avoid heat generation. After that, stirring was continued for 3 hours while maintaining the temperature. Furthermore, 0.6 g of methoquinone as a polymerization inhibitor and 145 g of 2-hydroxyethyl acrylate as a (meth)acrylate compound having a hydroxyl group were added, and the mixture was stirred at 85°C for 2 hours, yielding 1,400 g of urethane (meth)acrylate compound (B1-1) (weight average molecular weight: 3,000, number of functional groups: 2).

[0094] Urethane (meth)acrylate compounds (B1-2) to (B1-6) were obtained in the same manner as above, except that the polyol compounds, polyisocyanate compounds, and (meth)acrylate compounds having a hydroxyl group shown in Table 1 were used.

[0095] (Production of urethane (meth)acrylate compound (B1-7)) A reaction vessel equipped with a stirrer, a reflux condenser, a nitrogen inlet tube, and a thermometer was charged with 1,000 g of "PLACCEL FA2D" (manufactured by Daicel Corporation, polycaprolactone-modified hydroxyethyl acrylate) as a (meth)acrylate compound having a hydroxyl group, and stirring was initiated. Next, 0.6 g of dibutyltin laurate and 529 g of "DURANATE TPA-100" (manufactured by Asahi Kasei Corporation, NCO = 23.1%) as a polyisocyanate compound, and 1 g of methoquinone as a polymerization inhibitor were added to the (meth)acrylate compound, and the internal temperature was raised to 80 ° C. while paying attention to heat generation, and then the mixture was stirred for 3 hours while maintaining the temperature, to obtain 1,500 g of a urethane (meth)acrylate compound (B1-7) (weight average molecular weight: 3,000, number of functional groups: 3).

[0096]

[0097] The raw materials used are listed below: Diol compound: PEG-400 (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., polyethylene glycol), weight average molecular weight: 400

[0098] <Synthesis of Crosslinking Regulator> (Production of Crosslinking Regulator (C-5)) 120 g of "1,3-bisaminocyclohexane" (manufactured by Tokyo Chemical Industry Co., Ltd.) as an amine compound and 214 g of "jER828" (manufactured by Mitsubishi Chemical Corporation, bisphenol A-type epoxy resin) as an epoxy resin were added to a reaction vessel equipped with a stirrer, a reflux condenser, and a thermometer, and the mixture was stirred at 100°C. The temperature was then raised to 140°C, and the mixture was stirred for 2 hours while maintaining the temperature. 25 g of phenol novolak resin TD-2093Y (manufactured by DIC Corporation) with a melting point of 100°C was added to 200 g of the obtained solution, and the mixture was stirred at 150°C for 60 minutes. The molten solution was poured into a shallow dish, and after cooling, a solid mass was obtained. The obtained solid was coarsely pulverized with a hammer and repeatedly pulverized in a jet mill to a particle size of 4 μm or less, to obtain crosslinking regulator (C-5) with an average particle size of 1 μm. The melting point of the crosslinking regulator (C-5) was 75°C.

[0099] (Production of Crosslinking Regulator (C-6)) A solid mass was prepared in the same manner as in the production method of C-5 above, and repeatedly pulverized in a jet mill to a particle size of 40 μm or less, thereby obtaining a crosslinking regulator (C-6) having an average particle size of 15 μm. The melting point of the crosslinking regulator (C-6) was 80° C.

[0100] The materials used are listed below. (A-1) Multifunctional thiol: tris-[(3-mercaptopropionyloxy)-ethyl]-isocyanurate (manufactured by Tokyo Chemical Industry Co., Ltd.) (A-2) Multifunctional thiol: pentaerythritol tetrakis(3-mercaptopropionate) (manufactured by Tokyo Chemical Industry Co., Ltd.) (A-3) Multifunctional thiol: dipentaerythritol hexakis(3-mercaptopropionate) (manufactured by Tokyo Chemical Industry Co., Ltd.) (A-4) Multifunctional thiol: ethylene glycol bis(3-mercaptopropionate) (manufactured by Tokyo Chemical Industry Co., Ltd.) (B2-1) Multifunctional (meth)allyl compound: phthalic acid diallyl ester (manufactured by Tokyo Chemical Industry Co., Ltd.) (B2-2) Multifunctional (meth)allyl compound: 1,3-diallyl-5-propyl isocyanurate (manufactured by Tokyo Chemical Industry Co., Ltd.) (B2-3) Polyfunctional (meth)allyl compound: trimethylolpropane triallyl ether (manufactured by Osaka Soda Co., Ltd.) (C-1) Crosslinking regulator: ADEKA HARDNER EH-5019S [average particle size: 5 μm, melting point: 90 to 120° C.] (imidazole-type epoxy adduct manufactured by ADEKA Corporation) (C-2) Crosslinking regulator: FUJICURE FXR-1020 [average particle size: 5 μm, melting point: 120 to 130° C.] (amine-type isocyanate adduct manufactured by T&K TOKA Corporation) (C-3) Crosslinking regulator: FUJICURE FXR-1030 [average particle size: 5 μm, melting point: 130 to 145° C.] (amine-type isocyanate adduct manufactured by T&K TOKA Corporation) (C-4) Crosslinking regulator: ADEKA HARDNER EH-5057PK [average particle size: 2 μm, melting point: 75 to 85° C.] (amine-type epoxy adduct manufactured by ADEKA Corporation) (C-7) Crosslinking regulator: 1,3-bisaminocyclohexane [liquid at 25° C.] (liquid polyamine compound manufactured by Tokyo Chemical Industry Co., Ltd.) (C-8) Crosslinking regulator: ADEKA HARDNER EH-2021 [liquid at 25° C.] (liquid imidazole derivative manufactured by ADEKA Corporation) (D-1) Photopolymerization initiator: 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide

[0101] Examples 1-26 and Comparative Examples 1-5 The above components were added to a planetary mixer in the amounts shown in Table 2-4 below and mixed for 2 hours to obtain encapsulant resin compositions. The above-described evaluations were carried out using the obtained encapsulant resin compositions. The results are shown in Table 2-4.

[0102]

[0103]

[0104]

[0105] As a result of the above tests, it was found that the resin composition for an encapsulant of each Example, containing components (A) to (C), had high viscosity stability in an uncured state, and after curing, had high adhesion to a substrate, was resistant to cleaning solutions, had excellent light resistance, and was able to suppress bleeding out under high-temperature and high-humidity conditions.

[0106] On the other hand, in Comparative Example 1, a liquid polyamine compound other than the component (C) of the present invention was used, and therefore the encapsulant resin composition had reduced viscosity stability, and the cured product had poor adhesion to the substrate, poor resistance to cleaning solutions, and poor light resistance.

[0107] In Comparative Example 2, a liquid imidazole derivative that is not the component (C) of the present invention was used, and therefore the encapsulant resin composition had reduced viscosity stability, and the cured product had poor adhesion to the substrate, poor resistance to cleaning solutions, and reduced light resistance.

[0108] In Comparative Example 3, since the component (C) was not contained, the cured product of the encapsulant resin composition had reduced resistance to cleaning solutions, and bleed-out occurred under high temperature and high humidity conditions.

[0109] In Comparative Example 4, the component (B1) was not used, and therefore the encapsulant resin composition had reduced viscosity stability, and the cured product had reduced resistance to cleaning solutions.

[0110] In Comparative Example 5, since the component (A) was not contained, the cured product of the encapsulant resin composition had poor adhesion to the substrate, reduced resistance to cleaning liquids, and bleed-out occurred under high-temperature and high-humidity conditions.

Claims

1. A resin composition for encapsulation, comprising (A) a polyfunctional thiol having 2 to 6 thiol groups, (B) a compound having 2 to 3 polymerizable unsaturated bonds, and (C) a cross-linking adjuster, wherein the (B) compound having 2 to 3 polymerizable unsaturated bonds contains (B1) a bifunctional urethane (meth)acrylate, and the (C) cross-linking adjuster is an amine compound that is solid at 25°C.

2. The encapsulant resin composition according to claim 1, wherein the compound (B) having 2 to 3 polymerizable unsaturated bonds contains a polyfunctional (meth)allyl compound (B2).

3. A film liquid crystal panel sealed with the resin composition for sealing material according to claim 1 or 2.

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