A curable resin composition for use as a encapsulant for film liquid crystal panels, and a film liquid crystal panel with its edges encapsulated with the curable resin composition.

Abstract

The present invention provides a curable resin composition which contains (A) a multifunctional thiol compound having 2 to 6 thiol groups, (B) a multifunctional urethane (meth)acrylate compound having 2 to 3 (meth)acrylic groups, (C) a multifunctional allyl compound having 2 to 4 (meth)allyl groups, (D) a spherical filler that has an average particle diameter of 15 µm or less and (E) a photopolymerization initiator, wherein: the blending mass ratio (B) / (C) is 0.1 to 1.0; the ratio of the thiol groups in the component (A) to the polymerizable unsaturated bonds in the components (B) and (C) is 0.5 to 3.0; and the amount of the component (D) is 1 to 50 parts by mass relative to a total of 100 parts by mass of the components (A) to (C). This curable resin composition does not contaminate liquid crystals even in cases where the curable resin composition in an uncured state comes into contact with the liquid crystals, while being capable of maintaining the shape on a base material for a long period of time; and in addition, alignment disturbance of liquid crystals is not caused even in cases where a cured product of this curable resin composition is in contact with the liquid crystals under harsh wet heat conditions. Consequently, this curable resin composition is used in a sealing material for film liquid crystal panels, the sealing material exhibiting excellent followability to a base material regardless of changes in the temperature environment.

Description

[Technical Field]

[0001] The present invention relates to a curable resin composition for use as a encapsulant for film liquid crystal panels. More specifically, the present invention relates to a curable resin composition that does not contaminate liquid crystals even when in contact with them in an uncured state, maintains its shape on the substrate for a long time without wetting, spreading, or repelling, and furthermore, does not cause orientation disorder of the liquid crystals even when the cured product is in contact with the liquid crystals in a harsh humid and hot environment, and has excellent conformability to the substrate regardless of changes in the temperature environment. The present invention also relates to a film liquid crystal panel using an encapsulant made of the curable resin composition. [Background technology]

[0002] Liquid crystal panels are widely used for displaying images in various electronic devices, including mobile phones and personal computers. A liquid crystal panel typically consists of a pair of glass substrates with electrodes on their surfaces, a frame-shaped sealing material sandwiched between them, and a liquid crystal layer surrounded by the sealing material.

[0003] Conventionally, photocurable acrylic resin compositions have been used as encapsulants. However, while conventional acrylic resin compositions offer excellent workability and productivity, they have the problem of generating a large amount of outgassing during the manufacturing process, which reduces the adhesion between the encapsulant and the substrate. Furthermore, encapsulants are required to protect liquid crystals in harsh humid and hot environments, but conventional acrylic resin compositions have poor moisture barrier properties and are prone to decomposition. This leads to contamination of the liquid crystal by moisture and decomposition products in humid and hot environments, disrupting the orientation of the liquid crystals.

[0004] To address these problems, it is known that using a resin composition containing a thiol monomer having a thiol group and an en monomer having a carbon-carbon double bond can suppress outgassing and improve the adhesion of the encapsulant (Patent Document 1). Furthermore, Patent Document 1 confirms that by improving the moisture barrier properties and durability of the encapsulant, liquid crystal orientation disruption does not occur even when the encapsulant and liquid crystal are in contact under harsh humid and hot environments.

[0005] However, in the manufacturing of liquid crystal panels, there is a process in which the resin composition used as the encapsulant comes into contact with the liquid crystal while it is still uncured. In such a process, the encapsulant described in Patent Document 1 has the problem that the resin components dissolve into the liquid crystal, causing liquid crystal contamination and resulting in display defects. Furthermore, in recent years, film liquid crystal panels using flexible film materials as a substrate have attracted attention, and development is progressing. Unlike the encapsulants used for rigid glass substrates, the encapsulants used in these film liquid crystal panels are required to be highly flexible and tough, and to conform to the film substrate. Moreover, this conformability is required even after accelerated testing that simulates the temperature changes that film liquid crystal panels may be exposed to, considering actual use. However, the sealing material described in Patent Document 1 lacked flexibility and toughness, and did not conform well to the flexible film substrate, resulting in the problem that the sealing material peeled off the film during accelerated testing. Furthermore, from the perspective of improving the productivity of liquid crystal panels, the resin composition used as a encapsulant must not wet or repel on the substrate after coating. However, the encapsulant described in Patent Document 1 had the problem of repelling on the substrate. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2016-169298 [Overview of the project] [Problems that the invention aims to solve]

[0007] The present invention has been made in view of the above circumstances, and its objectives are to provide a curable resin composition for use as a encapsulant for film liquid crystal panels that does not contaminate liquid crystals even when in contact with liquid crystals in an uncured state, can maintain its shape on a substrate for a long time without wetting, spreading or repelling, and furthermore does not cause orientation disorder of liquid crystals even when the cured product is in contact with liquid crystals in a harsh humid and hot environment, and has excellent conformability to the substrate regardless of changes in the temperature environment, and to provide a film liquid crystal panel that uses the above curable resin composition as an encapsulant. [Means for solving the problem]

[0008] In order to solve the above problems, the inventors of the present invention have conducted extensive research and have focused on the fact that polyfunctional urethane (meth)acrylate compounds have high hydrophobicity with liquid crystals. They have found that by using a curable resin composition containing the urethane (meth)acrylate compound, a specific polyfunctional (meth)allyl compound, a polyfunctional thiol compound, and a spherical filler, it is possible to obtain a encapsulant for film liquid crystal panels that does not contaminate the liquid crystal even when in contact with it in an uncured state, can maintain its shape on the substrate for a long time without wetting or spreading or repelling, and furthermore, does not cause orientation disorder of the liquid crystal even when the cured product is in contact with the liquid crystal under harsh humid and hot environments. In addition, they have found that this encapsulant possesses both flexibility and toughness, and exhibits excellent conformability to the substrate regardless of changes in the temperature environment, thus completing the present invention.

[0009] In other words, the present invention is as follows: [1] to [2]. [1] The following components (A) to (E) (A) A polyfunctional thiol compound having 2 to 6 thiol groups, (B) A polyfunctional urethane (meth)acrylate compound having 2 to 3 (meth)acrylic groups, (C) A polyfunctional allyl compound having 2 to 4 (meth)allyl groups, (D) Spherical fillers with an average particle diameter of 15 μm or less, (E) Contains a photopolymerization initiator, The combined mass ratio (B) / (C) of (B) and (C) is between 0.1 and 1.0. The ratio of the functional group concentration of thiol groups in (A) to the total functional group concentration of polymerizable unsaturated bonds in (B) and (C) (thiol groups / polymerizable unsaturated bonds) is 0.5 to 3.0. A curable resin composition for use as a encapsulant for film liquid crystal panels, wherein (D) is 1 to 50 parts by mass relative to a total of 100 parts by mass of (A), (B), and (C). [2] A film liquid crystal panel having its edges sealed with the curable resin composition described in [1] above.

[0010] In this invention, "(meth)allyl compound" is a general term that includes both compounds having an allyl group and compounds having a methallyl group, and the same applies to "(meth)acrylic group," etc. In this invention, "○○~××" indicating a numerical range is a concept that includes the lower limit ("○○") and upper limit ("××") unless otherwise specified. In other words, it more precisely means "○○ or more and ×× or less." [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a curable resin composition for use as a encapsulant for film liquid crystal panels that does not contaminate the liquid crystal even when in contact with the liquid crystal in an uncured state, can maintain its shape on the substrate for a long time without wetting or spreading or repelling, does not cause orientation disorder of the liquid crystal even when the cured product is in contact with the liquid crystal in a harsh humid and hot environment, and exhibits excellent conformability to the substrate regardless of changes in the temperature environment. Another objective is to provide a film liquid crystal panel that uses the above curable resin composition as an encapsulant. [Modes for carrying out the invention]

[0012] The present invention will be described in detail below. The curable resin composition of the present invention is used as a encapsulant for film liquid crystal panels and comprises the following essential components: (A), (B), (C), (D), and (E).

[0013] <Polyfunctional thiol compound (A)> The polyfunctional thiol compound (A) is a compound having 2 to 6 thiol groups. The polyfunctional thiol compound (A) can be used alone or in combination of two or more. By containing such a compound, the thiol-ene reaction proceeds with other components and the curability can be enhanced. The formed thioether bond can change the bond angle flexibly compared with the bonds of atoms such as C, O, and N, so the cured product has high flexibility and can enhance the followability to the substrate of the sealing material. In addition, the cured product composed of thioether bonds has high flexibility of the bond angle and can be cured at a high density so that atoms fill the gaps between bonds, so it has high moisture barrier properties and can prevent the alignment disorder of the liquid crystal even after the damp heat test without being affected by moisture.

[0014] The polyfunctional thiol compound (A) is preferably a compound represented by the following formula 1.

Chemical formula

[0016] , 1 , , 1 , is an organic group having a valence of 2 to 6 and 10 to 60 carbon atoms.)

[0015] From the viewpoint of enhancing the moisture barrier property of the sealing material for the film liquid crystal panel and suppressing the alignment disorder even when exposed to a severe damp heat test, a is preferably an integer of 3 to 6. If a is within this range, a large curing shrinkage does not occur and the followability to the substrate after curing does not decrease, and a good cured product can be obtained. Also, R 1 is preferably trivalent to hexavalent from the same viewpoint. The carbon number of R 1 is 10 to 60, preferably 10 to 45, and more preferably 12 to 30. If the carbon number of R 1 is within this range, the crosslink density of the cured product of the curable resin composition is sufficient, the sealing material has excellent moisture barrier properties, and the alignment disorder of the liquid crystal can be suppressed even when exposed to a severe damp heat test.

[0016] An 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. Furthermore, its structure may contain groups such as ketone groups, ester groups, ether groups, hydroxyl groups, amide groups, thioether groups, isocyanurate groups, and glycoluryl groups.

[0017] Specifically, the polyfunctional thiol compound (A) includes dipentaerythritol hexakis(3-mercaptopropionate), trimethylolpropanetris(2-mercaptoacetate), trimethylolpropanetris(3-mercaptopropionate), trimethylolethanetris(2-mercaptoacetate), trimethylolethanetris(3-mercaptopropionate), pentaerythritol tetrakis(2-mercaptoacetate), pentaerythritol tetrakis(3-mercaptopropionate), 1,2,3-tris(2-mercaptoethylthio)propane, and 1,2,3-tris(3-mercaptopropylthio)propane. Examples include pan, 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, tris-[(3-mercaptopropionyloxy)-ethyl]-isocyanurate, etc. Among the compounds represented by Formula 1 above, polyfunctional thiols having a pentaerythritol skeleton, polyfunctional thiols having a dipentaerythritol skeleton, and polyfunctional thiols having an isocyanurate skeleton are preferred. Among these, dipentaerythritol hexakis(3-mercaptopropionate), pentaerythritol tetrakis(3-mercaptopropionate), and tris-[(3-mercaptopropionyloxy)-ethyl]-isocyanurate are preferred because they enhance the moisture barrier properties of the encapsulant, suppress orientation disorder of the liquid crystal even when exposed to harsh humid heat tests, and increase the flexibility of the cured product of the curable resin composition, thereby improving the substrate conformability of the encapsulant.

[0018] The polyfunctional thiol compound (A) may be a commercially available product or a synthesized product. For example, it can be obtained by esterifying a polyhydric alcohol such as pentaerythritol with a mercapto group-containing carboxylic acid such as 3-mercaptopropionic acid using a known method.

[0019] <Polyfunctional urethane (meth)acrylate compound (B)> The polyfunctional urethane (meth)acrylate compound (B) is obtained by reacting a diisocyanate compound, a polyol compound, and a (meth)acrylate compound having a hydroxyl group by a known method. The polyfunctional urethane (meth)acrylate compound (B) can be used alone or in combination of two or more types. Because such compounds have high hydrophobicity with liquid crystals, including such compounds reduces the solubility of the uncured curable resin composition in liquid crystals, preventing contamination of the liquid crystal even when in prolonged contact with it. Furthermore, it can strengthen the cured product of the curable resin composition and improve the conformability of the encapsulant to the substrate. In addition, the urethane groups contained can exhibit strong interactions such as hydrogen bonding with other urethane groups and other polar groups in the temperature range from -30°C or below to about 100°C, thus strengthening the cured product of the curable resin composition regardless of the temperature environment and improving the conformability of the encapsulant to the substrate. The polyfunctional urethane (meth)acrylate compound (B) is a compound having 2 to 3 (meth)acrylic groups. Having this number of (meth)acrylic groups prevents the cured product of the curable resin composition from becoming rigid, improving the conformability of the encapsulant to the substrate, and also prevents excessive polarity, thus maintaining compatibility with other components.

[0020] Any known compound can be used as the diisocyanate compound. Examples include aliphatic diisocyanates, alicyclic diisocyanates, and aromatic diisocyanates. Specifically, examples include aliphatic diisocyanates such as pentamethylene diisocyanate, hexamethylene diisocyanate, and trimethylhexamethylene diisocyanate; alicyclic diisocyanates such as isophorone diisocyanate, hydrogenated diphenyl diisocyanate, and norbornene diisocyanate; and aromatic diisocyanates such as xylylene diisocyanate, tolylene diisocyanate, and diphenylmethane diisocyanate. Among these, aliphatic and alicyclic diisocyanates are preferred from the viewpoint of preventing discoloration of the resulting sealant over time.

[0021] Known compounds can be used as the polyol compound. Examples include polyester polyols, polyether polyols, polycarbonate polyols, and polyols composed of hydrocarbons. From the viewpoint of not making the polarity of the polyfunctional urethane acrylate compound obtained after the reaction too high and improving the conformability of the encapsulant to the substrate, divalent diol compounds and trivalent triol compounds are preferred as the polyol compound.

[0022] As the polyester polyol, a compound obtained by condensation reaction of a dicarboxylic acid compound and a polyol compound can be used. Specifically, dicarboxylic acid compounds include succinic acid, adipic acid, pimelic acid, and sebacic acid. Among these, adipic acid and pimelic acid are preferred. Polyol compounds include, for example, diol compounds and triol compounds. Specifically, 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. Specifically, triol compounds include glycerin, 1,2,4-butanetriol, and trimethylolpropane. Among these, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, diethylene glycol, and glycerin are preferred.

[0023] As the polyether polyol, known compounds can be used. Specifically, 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, polypropylene glycol, and polyoxypropylene triol are preferred.

[0024] As the polycarbonate polyol, compounds obtained by transesterification of a diester carbonate and a polyol compound can be used. Specifically, diphenyl carbonate, dimethyl carbonate, and diethylene carbonate are examples of diester carbonates. Among these, diphenyl carbonate is preferred. Examples of polyol compounds include diol compounds and triol compounds. Specifically, 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. Specifically, triol compounds include glycerin, 1,2,4-butanetriol, and trimethylolpropane. Among these, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, diethylene glycol, and glycerin are preferred.

[0025] Known compounds can be used as the hydrocarbon polyol. Specifically, examples 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. Among these, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, and glycerin are preferred.

[0026] The (meth)acrylate compound having a hydroxyl group can be any known compound. Specifically, 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, etc. can be used. Among these, 2-hydroxyethyl acrylate and propylene glycol monoacrylate are preferred from the viewpoint of preventing discoloration of the encapsulant over time, increasing the flexibility of the cured product of the curable resin composition, and improving the conformability of the encapsulant to the substrate.

[0027] The weight-average molecular weight of the polyfunctional urethane (meth)acrylate compound (B) is preferably 1,000 to 15,000, and more preferably 3,000 to 10,000, from the viewpoint of achieving a balance between the following properties: the curable resin composition does not contaminate the liquid crystal even when in contact with the liquid crystal in an uncured state; the encapsulant suppresses disorder of liquid crystal orientation even when exposed to harsh humid heat testing; and the encapsulant has high conformability to the substrate regardless of the temperature environment, as well as being easy to handle. The weight-average molecular weight of the urethane (meth)acrylate is determined by gel permeation chromatography (GPC) using a calibration curve for standard polystyrene.

[0028] <Polyfunctional (meth)allyl compound (C)> The polyfunctional allyl compound (C) is a compound having 2 to 4 (meth)allyl groups. Only one type of the polyfunctional allyl compound (C) can be used alone, or two or more types can be used in combination. By containing (C), the toughness of the cured product of the curable resin composition can be increased, and the followability of the sealing material to the base material can be enhanced. In addition, since it is excellent in forming a crosslinked network with other components, the sealing material has excellent moisture barrier properties. Furthermore, since hydrolysis is less likely to occur during the moisture resistance test compared to the (meth)acrylic compound, the high moisture barrier properties of the sealing material can be maintained during the moisture resistance test, and the orientation disorder of the liquid crystal can be suppressed even when exposed to a severe damp heat test. The polyfunctional allyl compound (C) is preferably a compound represented by the following formula (2). [Chemical formula] (In the formula, b is an integer of 2 to 4. R 2 is a hydrogen atom or a methyl group. R 3 is a divalent to tetravalent organic group having 2 to 40 carbon atoms.) In the formula, R 2 is a hydrogen atom or a methyl group, and from the viewpoint of increasing the flexibility of the cured product of the curable resin composition and enhancing the followability of the sealing material to the base material, a hydrogen atom is preferable. b is an integer of 2 to 4, and within this range, the moisture barrier properties of the sealing material can be enhanced, the orientation disorder can be suppressed even when exposed to a severe damp heat test, and the flexibility of the cured product of the curable resin composition can be increased, and the followability of the sealing material to the base material can be enhanced. Also, from the same viewpoint, R 3 is divalent to tetravalent. The number of carbon atoms of R 3 is 2 to 40, preferably 2 to 30, and more preferably 2 to 25. If the number of carbon atoms of R 23 is within this range, the crosslink density of the cured product of the curable resin composition is sufficient, and the sealing material can obtain good moisture barrier properties, so the orientation disorder can be suppressed even when exposed to a severe damp heat test.

[0029] An 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. Furthermore, its structure may contain groups such as ketone groups, ester groups, ether groups, hydroxyl groups, amide groups, thioether groups, and isocyanurate groups.

[0030] For example, specific examples of compounds in which b in the formula is 2 include 1,4-cyclohexanedicarboxylic acid di(meth)allyl ester, isophthalate di(meth)allyl ester, phthalate di(meth)allyl ester, hexahydrophthalate di(meth)allyl ester, di(meth)allylmethylglycidyl 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, 2,2-bis(3-(meth)allyl-4-glycidyloxyphenyl)propane, 1,3-di(meth)allyl-5-glycidyl isocyanurate, and 1,3-di(meth)allyl cyanurate. Examples of compounds where b is 3 include triallyl isocyanurate, pentaerythritol tri(meth)allyl ether, glycerin tri(meth)allyl ether, and trimethylolpropane triallyl ether. Specific examples of compounds where b is 4 include 1,3,4,6-tetra(meth)allyl glycoluryl, 1,3,4,6-tetra(meth)allyl-3a-methyl glycoluryl, pentaerythritol tetra(meth)allyl ether, and tetra(meth)allyl oxyethane. Among the above (meth)allyl compounds, (meth)allyl compounds having an isocyanurate skeleton and (meth)allyl compounds having a pentaerythritol skeleton are preferred from the viewpoint of preventing discoloration of the encapsulant over time, improving the moisture barrier properties of the encapsulant, suppressing orientation disorder even when exposed to harsh moist heat tests, and further increasing the toughness of the cured product of the curable resin composition and improving the conformability of the encapsulant to the substrate. Specifically, 1,3-diallyl-5-glycidyl isocyanurate, triallyl isocyanurate, pentaerythritol triallyl ether, and pentaerythritol tetraallyl ether are preferred.

[0031] <Spherical filler (D)> Spherical filler (D) is a spherical filler made of inorganic or organic material with an average particle diameter of 15 μm or less. Spherical filler (D) can be used alone or in combination of two or more types. The inclusion of (D) improves the shape stability of the uncured curable resin composition, allowing it to maintain its shape on the substrate for a long time without spreading or repelling.

[0032] The spherical filler (D) has an average particle diameter of 15 μm or less, preferably 10 μm or less. Within this average particle diameter range, the flexibility and adhesion of the curable resin composition to the substrate are not impaired, and the conformability of the encapsulant to the substrate can be maintained. The average particle diameter can be measured using a commercially available particle size distribution analyzer such as the Microtrac MT-3000II manufactured by Microtrac-Bell.

[0033] Examples of the spherical filler (D) made of inorganic materials include silica, silicon carbide, calcium carbonate, magnesium carbonate, alumina, titania, calcium oxide, magnesium oxide, magnesium hydroxide, and aluminum hydroxide. Among these, silica is preferred from the viewpoint of not impairing the moisture barrier properties of the sealing material and improving shape stability while maintaining the ability to suppress orientation disorder even when exposed to harsh humid heat tests. Examples of spherical fillers (D) made of organic material include acrylic particles, urethane particles, styrene particles, melamine particles, and acrylic-styrene particles. Among these, acrylic particles and urethane particles are preferred from the viewpoint of not impairing the flexibility of the curable resin composition and adhesion to the substrate, and maintaining the conformability of the sealant to the substrate.

[0034] <Photopolymerization initiator (E)> Photopolymerization initiator (E) is added to promote the photocuring reaction of polymerizable compounds when polymerizable compounds are added to (A), (B), (C), and other materials, thereby reducing the amount of light irradiation required for curing the curable resin composition. Photopolymerization initiator (D) can be used alone or in combination of two or more types. 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 shortening reaction time and improving productivity.

[0035] Examples of photoradical polymerization initiators include 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxycyclohexylphenyl 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 Examples include ru-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 1,2-octanedion-1-[4-(phenylthio)phenyl]-2-(O-benzoyl oxime), and 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3yl]ethanone-1-(O-acetyloxime).

[0036] Examples of photocationic polymerization initiators 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.

[0037] Examples of photoanionic polymerization initiators include acetophenone o-benzoyl oxime, nifedipine, 1,5,7-triazabicyclo[4,4,0]deca-5-ene 2-(9-oxoxanthene-2-yl)propionic acid, 2-nitrophenylmethyl 4-methacryloyloxypiperidine-1-carboxylate, 1,2-diisopropyl-3-[bis(dimethylamino)methylene]guanidium 2-(3-benzoylphenyl)propionate, and 1,2-dicyclohexyl-4,4,5,5-tetramethylbiguanidium n-butyltriphenyl borate.

[0038] <Polyfunctional (meth)acrylic compound (F)> The curable resin composition of the present invention may contain a polyfunctional (meth)acrylic compound (F) to the extent that it does not impede the objectives of the present invention. The polyfunctional (meth)acrylic compound (F) acts as a compatibilizer between the polyfunctional urethane (meth)acrylate compound (B) and other components, and can improve the performance of preventing contamination of liquid crystals even when the uncured product of the curable resin composition is in contact with the liquid crystal for a long period of time. From the viewpoint of not impeding the curability of the curable resin composition, the polyfunctional (meth)acrylic compound is preferably one having two or more (meth)acrylic groups. Furthermore, from the viewpoint of not reducing the flexibility of the cured product of the curable resin composition and not impeding its conformability to the substrate, it is preferable that it has six or fewer (meth)acrylic groups. Known compounds can be used as such polyfunctional (meth)acrylic compounds. Among them, the compound represented by the following formula 3 is preferred from the viewpoint of acting better as a compatibilizer and not reducing the flexibility of the cured product of the curable resin composition and not impeding its conformability to the substrate. [ka] (In the formula, c is an integer between 2 and 4. 4 R is a hydrogen atom or a methyl group. 5 This group consists of a hydrocarbon group having 2 to 14 carbon atoms, a group consisting of an ether oxygen (-O-) and a hydrocarbon group having 2 to 14 carbon atoms, a group consisting of a hydroxyl group and a hydrocarbon group having 2 to 14 carbon atoms, an isocyanurate skeleton, and a group consisting of at least one group selected from ether oxygen, hydroxyl group, and hydrocarbon, or a bisphenol skeleton and a group consisting of at least one group selected from ether oxygen, hydroxyl group, and hydrocarbon.

[0039] Examples of polyfunctional (meth)acrylic compounds where c is 2 include, specifically, 1,3-butanediol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, and tripropylene glycol di(meth)acrylate. Examples include polypropylene glycol di(meth)acrylate, ethylene oxide-modified bisphenol A di(meth)acrylate, propylene oxide-modified bisphenol A di(meth)acrylate, ethylene oxide-modified bisphenol F di(meth)acrylate, dimethylol dicyclopentadiene di(meth)acrylate, neopentyl glycol di(meth)acrylate, ethylene oxide-modified isocyanurate di(meth)acrylate, 2-hydroxy-3-(meth)acryloyloxypropyl(meth)acrylate, and polyetherdiol di(meth)acrylate.

[0040] Examples of polyfunctional (meth)acrylic compounds in which c is 3 or 4 include trimethylolpropane tri(meth)acrylate, caprolactone-modified trimethylolpropane tri(meth)acrylate, ethylene oxide-added trimethylolpropane tri(meth)acrylate, propylene oxide-added trimethylolpropane tri(meth)acrylate, ethylene oxide-added isocyanuric acid tri(meth)acrylate, ethoxylated isocyanuric acid triacrylate, pentaerythritol tri(meth)acrylate, glycerin tri(meth)acrylate, propylene oxide-added glycerin tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, and pentaerythritol tetra(meth)acrylate.

[0041] The content of the polyfunctional (meth)acrylic compound (F) in the curable resin composition of the present invention is 0 to 25 parts by mass, preferably 1 to 15 parts by mass, based on 100 parts by mass of the total of (A), (B), and (C).

[0042] <Surfactant (G)> The curable resin composition of the present invention may contain a surfactant (G) to the extent that it does not hinder the objectives of the present invention. Because surfactant (G) has high hydrophobicity, its inclusion in the curable resin composition improves the moisture barrier properties of the encapsulant, and further suppresses the disorder of liquid crystal orientation even when exposed to harsh moist heat tests. Known silicone-based surfactants, fluorine-based surfactants, acrylic-based surfactants, etc., can be used as surfactant (G) without particular limitation, but fluorine-based surfactants are preferred from the viewpoint of improving moisture barrier properties. Commercially available fluorine-based surfactants include, specifically, DIC Corporation's "Megafac F-410," "F-430," "F-444," "F-472SF," "F-477," "F-552," "F-553," "F-554," "F-555," "F-556," "F-558," "F-559," "F-561," "R-94," "RS-72-K," and "RS-75." These surfactants may be used individually or in combination of two or more.

[0043] The amount of surfactant (G) in the curable resin composition of the present invention is 0 to 1 part by mass, preferably 0.01 to 0.2 parts by mass, based on 100 parts by mass of the total of (A), (B), and (C).

[0044] <Silane coupling agent (H)> The curable resin composition of the present invention may contain a silane coupling agent (H) to the extent that it does not hinder the objectives of the present invention. The silane coupling agent (H) improves the interaction with other components and the substrate, and by including it in the curable resin composition, the toughness and adhesion to the substrate of the cured product of the curable resin composition can be improved, and the ability to follow the substrate regardless of changes in the temperature environment can be further enhanced. Known silane coupling agents can be used without particular limitation, but from the viewpoint of preventing contamination of the liquid crystal by bleed-out of the silane coupling agent when the encapsulant is used for a long period of time, causing disorder of the liquid crystal alignment, those having reactive functional groups such as (meth)acrylic groups, vinyl groups, thiol groups, epoxy groups, and isocyanate groups are preferred. Specifically, examples include 3-(meth)acryloxypropylmethyldimethoxysilane, 3-(meth)acryloxypropylmethyltrimethoxysilane, 3-(meth)acryloxypropylmethyldiethoxysilane, 3-(meth)acryloxypropylmethyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropylmethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, and 3-isocyanatetopropyltriethoxysilane. These silane coupling agents may be used alone or in combination of two or more.

[0045] The content of the silane coupling agent (H) in the curable resin composition of the present invention is 0 to 10 parts by mass, preferably 1 to 5 parts by mass, based on 100 parts by mass of the total of (A), (B), and (C).

[0046] <Other ingredients> The curable resin composition of the present invention may contain additives other than the polyfunctional (meth)acrylic compound (F), surfactant (G), and silane coupling agent (H) described above, to the extent that they do not impede the objectives of the present invention, such as epoxy compounds, curing accelerators, ultraviolet absorbers, light stabilizers, antioxidants, polymerization inhibitors, leveling agents, adhesion promoters, plasticizers, defoamers, light-shielding materials, conductive materials, and spacers.

[0047] <Composition ratio (mixing ratio)> The curable resin composition of the present invention contains (B), which has the property of being poorly miscible with liquid crystals, thereby reducing the liquid crystal contamination in the uncured state. Furthermore, in the curable resin composition of the present invention, a thiol-ene reaction proceeds between the thiol group of the polyfunctional thiol compound (A) and the polymerizable unsaturated bonds of the polyfunctional urethane (meth)acrylate compound (B) and the polyfunctional (meth)allyl compound (C), yielding a cured product. The formed thioether bond can flexibly change its bond angle, increasing the flexibility of the cured product of the curable resin composition and improving the conformability of the encapsulant to the substrate. In addition, the urethane groups contained in the polyfunctional urethane (meth)acrylate compound (B) can exhibit strong interactions such as hydrogen bonding with other urethane groups and other polar groups even in the low to high temperature range, so the cured product is toughened regardless of the temperature environment, improving the conformability of the encapsulant to the substrate. Furthermore, the cured product consisting of thioether bonds can harden to a high density, with atoms filling the gaps between bonds due to the high flexibility of the bond angles. This results in high moisture barrier properties, and even when exposed to harsh humid heat tests, it is unaffected by moisture and suppresses liquid crystal orientation disorder. Moreover, the inclusion of spherical filler (D) improves the shape stability of the uncured curable resin composition, allowing it to maintain its shape on the substrate for extended periods without wetting, spreading, or repelling. Thus, in order for the curable resin composition of the present invention to reduce liquid crystal contamination even when in contact with liquid crystal in an uncured state, and to maintain its shape on the substrate for extended periods without wetting, spreading, or repelling, and for the encapsulant made from the cured product of the curable resin composition to suppress liquid crystal orientation disorder even when in contact with liquid crystal in harsh humid heat environments, as well as to improve conformability to the substrate regardless of the temperature environment, all of (A), (B), (C), and (D) are indispensable. Furthermore, by using (E) in addition to the curable resin composition containing (A), (B), (C), and (D), the above effects can be achieved by light irradiation alone. Generally, the inclusion of (D) reduces the light transmittance in the curable resin composition, making deep curing by light irradiation alone difficult. However, in the curable resin composition of the present invention, the polyfunctional thiol compound (A) also contributes as a chain transfer agent, so sufficient deep curing can be achieved by light irradiation alone.In addition, by blending (B) and (C) in a mass ratio (B) / (C) of 0.1 to 1.0, and by blending (D) in a ratio of 1 to 50 parts by mass for every 100 parts by mass of (A), (B), and (C), the curable resin composition will not contaminate the liquid crystal even when in contact with the liquid crystal in an uncured state, will maintain its shape on the substrate for a long time without wetting or spreading, and will not cause disorder of the liquid crystal orientation even when the cured product is in contact with the liquid crystal in a harsh humid and hot environment, and will also exhibit excellent conformability to the substrate regardless of changes in the temperature environment. The thiol group functional group concentration is expressed as: (A) parts by mass in a total of 100 parts by mass of (A), (B), and (C) × (A) number of thiol groups / (A) molecular weight. The total of the polymerizable unsaturated bond functional group concentrations in (B) and (C) is expressed as: [(A) parts by mass in a total of 100 parts by mass of (B), (B), and (C) × (B) number of (meth)acrylic groups / (B) molecular weight] + [(C) parts by mass in a total of 100 parts by mass of (A), (B), and (C), × (C) number of allyl groups / (C) molecular weight].

[0048] In the curable resin composition of the present invention, in order to enhance the non-contamination of liquid crystals, to prevent further contamination of liquid crystals even when in contact with liquid crystals in an uncured state, and to enhance the flexibility and toughness of the cured product of the curable resin composition, and to further improve the conformability of the encapsulant to the substrate regardless of changes in the temperature environment, it is preferable to contain 10 parts by mass or more of (B) in a total of 100 parts by mass of (A), (B), and (C). Furthermore, in order to enhance the moisture barrier properties of the encapsulant and further suppress orientation disorder under harsh humid heat testing, it is preferable to contain 20 parts by mass or less of (B) in a total of 100 parts by mass of (A), (B), and (C). In other words, in order to achieve a higher level of performance in all aspects, such as the curable resin composition not contaminating the liquid crystal even when it comes into contact with the liquid crystal in an uncured state, suppressing disorder of liquid crystal orientation even when the encapsulant is exposed to harsh humid heat tests, and the encapsulant having high conformability to the substrate regardless of the temperature environment, it is preferable that (B) be contained in 100 parts by mass or more and 20 parts by mass or less of (A), (B), and (C) in total. Furthermore, in order to enhance the moisture barrier properties of the encapsulant and further suppress orientation disorder under harsh humid heat testing, the mixing mass ratio (B) / (C) of (B) to (C) in the curable resin composition of the present invention should be 0.1 to 0.6. In order to enhance the flexibility and toughness of the cured product of the curable resin composition and further improve the conformability of the encapsulant to the substrate, the mixing mass ratio (B) / (C) of (B) to (C) should be 0.2 to 1.0. In order to enhance the properties and toughness, and to further improve the conformability of the encapsulant to the substrate regardless of changes in the temperature environment, it is preferable that the mixing mass ratio of (B) and (C), (B) / (C), is 0.3 to 1.0. In other words, in order to achieve a higher level of performance in all aspects, such as suppressing liquid crystal orientation disorder even when the encapsulant is exposed to severe humid heat testing, and ensuring that the encapsulant has high conformability to the substrate regardless of the temperature environment, it is preferable that the mixing mass ratio of (B) and (C), (B) / (C), is 0.3 to 0.6. Furthermore, in order to enhance the moisture barrier properties of the encapsulant and further suppress orientation disorder under harsh humid heat testing, the ratio of the functional group concentration of thiol groups in (A) to the total functional group concentrations of polymerizable unsaturated bonds in (B) and (C) (thiol group / polymerizable unsaturated bond) is preferably 0.7 to 2.3. In order to enhance the flexibility and toughness of the cured product of the curable resin composition and further improve the conformability of the encapsulant to the substrate, the ratio of the functional group concentration of thiol groups in (A) to the total functional group concentrations of polymerizable unsaturated bonds in (B) and (C) (thiol group / polymerizable unsaturated bond) is preferably 0.7 to 2.5. In order to enhance the flexibility and toughness of the cured product and to improve the conformability of the encapsulant to the substrate regardless of changes in the temperature environment, it is preferable that the ratio of the total functional group concentration of thiol groups in (A) to the functional group concentrations of polymerizable unsaturated bonds in (B) and (C) (thiol group / polymerizable unsaturated bond) be 0.8 to 2.4. In other words, in order to achieve a higher level of performance in all aspects, such as suppressing liquid crystal orientation disorder even when the encapsulant is exposed to harsh humid heat tests and the encapsulant having high conformability to the substrate regardless of the temperature environment, it is preferable that the ratio of the total functional group concentration of thiol groups in (A) to the functional group concentrations of polymerizable unsaturated bonds in (B) and (C) (thiol group / polymerizable unsaturated bond) be 0.8 to 2.3. In addition, in order to improve the shape stability of the uncured curable resin composition in the present invention and enable it to maintain its shape on the substrate without wetting or spreading or repelling, it is preferable that (D) is 2 to 50 parts by mass per 100 parts by mass of the total of (A), (B), and (C). Furthermore, in order to maintain the flexibility and toughness of the cured product of the curable resin composition and to further improve the conformability of the sealing material to the substrate regardless of changes in the temperature environment, it is preferable that (D) is 1 to 40 parts by mass per 100 parts by mass of the total of (A), (B), and (C). In other words, in order for the curable resin composition to maintain its shape on the substrate for a long time without wetting or spreading or repelling in an uncured state, and for the sealing material to have high conformability to the substrate regardless of the temperature environment, it is preferable that (D) is 2 to 40 parts by mass per 100 parts by mass of the total of (A), (B), and (C). Furthermore, in the curable resin composition of the present invention, the ratio of (E) to 100 parts by mass of the total of (A), (B), and (C) is preferably 0.01 to 10.0 parts by mass, and more preferably 0.1 to 10.0 parts by mass. By setting the content of (E) within the above range, it is possible to obtain a sealing material that does not cause orientation disturbance of the liquid crystal even when in contact with the liquid crystal under harsh humid and hot environments, and that exhibits excellent conformability to the substrate regardless of changes in the temperature environment.

[0049] <Film LCD Panel> The film liquid crystal panel of the present invention includes, for example, dimming members that control transparency or opacity solely by the orientation of liquid crystals, and display elements that display images like a display. The film liquid crystal panel of the present invention, for example, has a pair of substrates placed opposite each other, the periphery of which is sealed with a sealing material for the film liquid crystal panel, and the liquid crystal material is present between them. Here, the substrate is a transparent plastic film base material such as polyethylene terephthalate, polycarbonate, cycloolefin (co)polymer, PMMA, or polyimide, on which silver or copper electrodes or transparent electrodes such as ITO or PEDOT are attached. It also includes cases on which an alignment film or the like is further formed on the transparent electrodes. The film liquid crystal panel of the present invention is a liquid crystal panel formed on a substrate using the above-mentioned transparent plastic film substrate, and the sealing material for the film liquid crystal panel is a sealing material used for the above-mentioned film liquid crystal panel.

[0050] <Formation of film liquid crystal panels> The film liquid crystal panel of the present invention is formed by applying the curable resin composition of the present invention to one of a pair of substrates, dropping liquid crystal onto the inside of the substrate, placing the other substrate on top, and curing the curable resin composition by irradiating it with light. Alternatively, one of the substrates may be formed by applying a polymer-dispersed liquid crystal containing liquid crystal and the curable resin composition to one of a pair of substrates, placing the other substrate on top, curing the polymer-dispersed liquid crystal by irradiating it with light, then applying the curable resin composition of the present invention to the outer periphery, and curing the curable resin composition by irradiating it with light. The method of applying the above-mentioned curable resin composition is not particularly limited, and methods such as using coating equipment such as dispenser coating, inkjet method, or screen printing method, or applying by hand with a syringe or brush, can be applied. The light source used to irradiate the above-mentioned curable resin composition is not particularly limited and can be, for example, 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, electron beam irradiation devices, etc. The contamination resistance of film liquid crystal panels can be evaluated not only by the method described above, which involves forming the film liquid crystal panel and applying voltage to check the alignment, but also by measuring the voltage retention rate. The voltage retention rate is an evaluation method that checks how well the charge accumulated in the liquid crystal cell after a certain period of time is retained when a voltage is applied. If the liquid crystal is contaminated, the charge will not be retained and the voltage retention rate will decrease. A good voltage retention rate of 90% or more is preferable for contaminated liquid crystal panels, and more preferably 95% or more. [Examples]

[0051] Next, the present invention will be described in more detail with reference to examples and comparative examples. <Evaluation Method> The curable resin compositions in each example and comparative example were evaluated for their performance by the method described below.

[0052] <Liquid crystal non-contaminating> 0.025 g of a curable resin composition was added to a sample vial, followed by 1 g of liquid crystal (Merck MLC-7021-000), and the sample was left to stand at 25°C for 1 hour. Afterward, ultraviolet irradiation (1000 mJ / cm²) was performed using a high-pressure mercury lamp. 2The curable resin composition was cured by performing the following procedure and heated at 100°C for 2 hours. After 2 hours, the cured material and liquid crystal were separated using a centrifuge, and the liquid crystal was injected into an ITO-coated glass substrate liquid crystal cell (KSSZ-05 / B107MINX05, manufactured by EHC Corporation). Using a liquid crystal property evaluation system (6245, manufactured by Toyo Technica Corporation), an initial voltage of 5V AC was applied to the liquid crystal cell at 25°C for 64μs, and the voltage ratio before and after a frame time of 16.7ms was multiplied by 100 to calculate the voltage retention rate. A higher voltage retention rate indicates that the liquid crystal is less susceptible to contamination, and in each table, the voltage retention rate is listed as liquid crystal non-contamination. <Shape stability> On a 40mm x 45mm glass substrate (RT-DM88-PIN, manufactured by EHC Corporation) with a transparent electrode and alignment film applied in that order, masking tape was applied, and then the curable resin compositions prepared in the examples and comparative examples were coated using an applicator to a film thickness of 100 μm. The masking tape was then removed to form a 25mm x 25mm square shape of the curable resin composition. After that, it was left to stand for 2 hours at 25°C under light shielding, and the side lengths of the square-shaped curable resin composition were measured. Note that the smaller the change in the side length of the square shape before and after standing, the less wetting and repulsion there is, and the higher the shape stability. The amount of change in side length is recorded in each table. ◎: The change in side length is within ±1 mm. ○: The change in side length exceeds ±1 mm but is within ±2 mm. ×: The side length is changing by more than ±2mm. <Curability> The curable resin compositions prepared in the examples and comparative examples were coated onto glass using an applicator to a film thickness of 100 μm, and then irradiated with ultraviolet light (200 mJ / cm²) using a high-pressure mercury lamp. 2 The following procedure was performed. Afterwards, the surface was rubbed back and forth five times with a non-woven wiper (Kimwipes manufactured by Nippon Paper Crecia), and the degree of scratching was visually checked. Note that the fewer or no scratches were found, the higher the hardening ability, and the number of scratches was recorded in each table. ◎: No damage found (0 items) ○: The number of wounds is 5 or less. ×: The number of wounds exceeds 5, or the wounds remain in a liquid state.

[0053] <Disruption of orientation under harsh humid and hot conditions> On a 40mm x 45mm glass substrate (RT-DM88-PIN, manufactured by EHC Corporation) with a transparent electrode and alignment film applied in that order, the curable resin compositions prepared in the examples and comparative examples were applied in a 35mm x 40mm square frame shape (line width: 1mm) using a dispenser (Shot Master, manufactured by Musashi Engineering Co., Ltd.), and liquid crystal (MLC-11900-000, manufactured by Merck) was dropped inside the curable resin composition drawn on the frame. Next, the glass substrate and the opposing glass substrate were bonded together under reduced pressure and left to stand at 25°C for 1 hour. Ultraviolet irradiation (1000mJ / cm²) was performed using a high-pressure mercury lamp. 2 A liquid crystal panel was obtained by performing the following procedure. The liquid crystal panel prepared in the same manner as above was exposed to 60°C and 90%RH conditions for 1000 hours, and then driven in a halftone display state with a voltage of AC 5V. The orientation disorder of the liquid crystals near the encapsulant, which is made of cured resin composition, was observed with a polarizing microscope. Note that the shorter the distance over which the orientation disorder spreads from the edge of the encapsulant, the less the orientation disorder is likely to occur, and the distance over which the orientation disorder spreads is indicated in each table. ◎: The orientation disorder does not extend beyond 0.3 mm from the edge of the sealing material. ○: Orientation disorder extends beyond 0.3 mm from the edge of the sealant, but does not extend beyond 0.6 mm. ×: Orientation disorder extends beyond 0.6 mm from the edge of the sealing material.

[0054] <Substrate followability> The curable resin compositions prepared in the examples and comparative examples were coated onto a 100 μm thick polyethylene terephthalate (PET) film using an applicator to a film thickness of 100 μm, and then irradiated with ultraviolet light (1000 mJ / cm²) using a high-pressure mercury lamp. 2The curable resin composition was cured by performing the following procedure. The resulting cured PET film was cut into rectangular shapes measuring 100 mm in length and 10 mm in width to obtain samples. The obtained samples were subjected to bending tests using an MIT testing machine (BE-202, manufactured by Tester Industries Co., Ltd.) (conditions: load 1N, bending speed 175 cpm, bending radius 2.5 mm, bending speed 135°). The test samples were visually inspected every 5000 bending cycles to check for cracks or peeling. Note that a higher number of bending cycles before cracks or peeling occurred indicates better substrate conformability, and the number of bending cycles at which cracks or peeling occurred is recorded in each table. ◎: No cracks or peeling even after bending 20,000 times (5,000 times x 4). ○: Cracks or peeling may occur after 20,000 cycles (5,000 cycles x 4) or after 15,000 cycles (5,000 cycles x 3). ×: Cracks or peeling occur within 10,000 cycles (5,000 cycles x 2).

[0055] <Substrate conformability after accelerated temperature change test> The curable resin compositions prepared in the examples and comparative examples were coated onto a 100 μm thick polyethylene terephthalate (PET) film using an applicator to a film thickness of 100 μm, and then irradiated with ultraviolet light (1000 mJ / cm²) using a high-pressure mercury lamp. 2 The curable resin composition was cured by performing the following procedure. The resulting cured PET film was cut into rectangular shapes measuring 100 mm in length and 10 mm in width to obtain samples. The obtained samples were subjected to accelerated temperature change tests, consisting of 200 heating and cooling shocks (-30°C, 30 minutes ⇔ 80°C, 30 minutes). Then, a bending test was performed using an MIT testing machine (BE-202, manufactured by Tester Industries Co., Ltd.) (conditions: load 1N, bending speed 175 cpm, bending radius 2.0 mm, bending speed 135°). The test samples were visually inspected every 5000 bending cycles to check for cracks or peeling. The more bending cycles required before cracks or peeling occurred, the better the substrate conformability. The number of bending cycles at which cracks or peeling occurred is recorded in each table. ◎: No cracks or peeling even after bending 20,000 times (5,000 times x 4). ○: Cracks or peeling may occur after 20,000 cycles (5,000 cycles x 4) or after 15,000 cycles (5,000 cycles x 3). ×: Cracks or peeling occur within 10,000 cycles (5,000 cycles x 2).

[0056] <Polyfunctional thiol compound (A)> A-1: Dipentaerythritol hexakis (3-mercaptopropionate) [Number of thiol groups: 6] A-2: Pentaerythritol tetrakis(3-mercaptopropionate) [Number of thiol groups: 4] A-3: Tris-[(3-mercaptopropionyloxy)-ethyl]-isocyanurate[3 thiol groups]

[0057] <Synthesis of polyfunctional urethane (meth)acrylate (B)> [Synthesis of polyol compound (b-1)] In a reaction vessel equipped with a stirrer, rectification column, nitrogen inlet tube, and thermometer, 151.5 parts by mass of pimelic acid and 187.3 parts by mass of diethylene glycol were charged and heated to 140°C under a nitrogen atmosphere, then stirred. 0.01 parts by mass of tetrabutyl titanate was added, and the temperature was raised to 220°C to carry out the dehydration reaction. The reaction was then held at 220°C to continue the dehydration reaction. After 18 hours from the start of the dehydration reaction, the contents were cooled to obtain diol compound (b-1) (weight-average molecular weight: 1,000).

[0058] [Synthesis of polyol compound (b-2)] In a reaction vessel equipped with a stirrer, rectification column, nitrogen inlet tube, and thermometer, 150.2 parts by mass of adipic acid and 158.3 parts by mass of 3-methyl-1,5-pentanediol were charged and heated to 140°C under a nitrogen atmosphere, and stirred. 0.01 parts by mass of tetrabutyl titanate was added, and the temperature was raised to 220°C to carry out the dehydration reaction. The reaction was then held at 220°C to continue the dehydration reaction. After 18 hours from the start of the dehydration reaction, the contents were cooled to obtain diol compound (b-2) (weight-average molecular weight: 1,500).

[0059] [Synthesis of polyol compound (b-3)] In a reaction vessel equipped with a stirrer, rectification column, air condenser, thermometer, receiver, and vacuum device, 160.3 parts by mass of diphenyl carbonate, 234.1 parts by mass of 1,6-hexanediol, and 0.1 parts by mass of tetrabutyl titanate were charged and heated to 100°C under a reduced pressure of 10 Torr, and stirred for 5 hours. The by-product phenol was removed by distillation, and the contents were cooled to obtain the diol compound (b-3) (weight-average molecular weight: 600).

[0060] [Synthesis of urethane (meth)acrylate (B-1)] In a reaction vessel equipped with a stirrer, reflux condenser, nitrogen inlet tube, and thermometer, 101.1 parts by mass of polyol compound (b-1) was charged, and stirring was started. Next, 0.1 parts by mass of dibutyltin laurate and 32.1 parts by mass of isophorone diisocyanate as diisocyanate were added, and the internal temperature was raised to 80°C while paying attention to the exothermic reaction, and then the mixture was stirred for 3 hours while maintaining the temperature. Furthermore, 0.1 parts by mass of methoquinone as a polymerization inhibitor and 24.0 parts by mass of 2-hydroxyethyl acrylate as a (meth)acrylate having a hydroxyl group were added, and the mixture was stirred at 85°C for 2 hours to obtain urethane (meth)acrylate (B-1) (weight-average molecular weight: 3000).

[0061] [Composition of (B-2) to (B-5)] Polyfunctional urethane (meth)acrylates (B-2) to (B-5) were obtained in the same manner as described above, except that the polyol compounds, diisocyanate compounds, and (meth)acrylate compounds having a hydroxyl group shown in Table 1 were used. [Table 1]

[0062] <Polyfunctional allyl compound (C)> C-1: 1,3-diallyl-5-glycidyl isocyanurate [Number of allyl groups: 2] C-2: Triallyl isocyanurate [Number of allyl groups: 3] C-3: Pentaerythritol tetraallyl ether [Number of allyl groups: 4] C-4: Ethylene glycol monoallyl AL [Number of allyl groups: 1]

[0063] <Spherical filler (D)> D-1:J-4P [Average particle size: 2.2μm] Acrylic particles manufactured by Negami Kogyo Co., Ltd. D-2: AEROSIL RX-200 [Average particle size: 12nm] Silica particles manufactured by Nippon Aerosil Co., Ltd. D-3:C-600T [Average particle size: 10 μm] Urethane particles manufactured by Negami Kogyo Co., Ltd. D-4:C-400T [Average particle size: 15μm] Urethane particles manufactured by Negami Kogyo Co., Ltd. D-5: SE-050T [Average particle size: 46 μm] Acrylic particles manufactured by Negami Kogyo Co., Ltd.

[0064] <Photopolymerization initiator (E)> E-1: Bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide E-2: 1-Hydroxycyclohexylphenyl ketone E-3: 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide

[0065] <(F) Component: Polyfunctional (meth)acrylate> F-1: Pentaerythritol tetraacrylate F-2: Trimethylolpropane trimethacrylate

[0066] <(G) Ingredient: Surfactant> G-1: Megafuck F-477, manufactured by DIC Corporation. G-2: Megafuck F-554, manufactured by DIC Corporation.

[0067] <(H) Component: Silane coupling agent> H-1:3-Methacryloxypropyltrimethoxysilane H-2:3-mercaptopropyltrimethoxysilane

[0068] [Example 1] The above components were added to a planetary mixer in the amounts shown in Tables 2 and 3 below, and mixed and stirred for 2 hours to obtain a curable resin composition. The curable resin composition was used for various evaluations. The results are shown in Tables 2-1, 2-2, 2-3, 3-1, and 3-2. [Table 2-1] [Table 2-2] [Table 2-3]

[0069] [Table 3-1] [Table 3-2]

[0070] The results of the above tests showed that the curable resin compositions of each example, by containing appropriate amounts of components (A) to (E) as specified in the present invention, exhibited excellent liquid crystal non-contamination properties, could maintain their shape on the substrate for a long time without wetting, spreading, or repelling, could be cured even with low integrated light intensity, did not cause disorder of liquid crystal orientation after the moist heat test, and had high conformability to the substrate regardless of the temperature environment.

[0071] On the other hand, in Comparative Example 1, because it did not contain the polyfunctional thiol compound (A), the curable resin composition had low photocurability, and the encapsulant for film liquid crystal panels obtained by curing the curable resin composition suffered from liquid crystal orientation disorder in severe humid heat tests and also had poor conformability to the substrate. In Comparative Example 2, because it did not contain the polyfunctional urethane (meth)acrylate compound (B), the curable resin composition had poor liquid crystal contamination resistance, and the encapsulant for film liquid crystal panels obtained by curing the curable resin composition suffered from liquid crystal orientation disorder in severe humid heat tests and also had poor conformability to the substrate. In Comparative Example 3, because it did not contain the polyfunctional allyl compound (C), the encapsulant for film liquid crystal panels obtained by curing the curable resin composition suffered from liquid crystal orientation disorder in severe humid heat tests and also had poor conformability to the substrate. In Comparative Example 4, because the number of functional groups of the polyfunctional allyl compound (C) was small, the encapsulant for film liquid crystal panels obtained by curing the curable resin composition suffered from liquid crystal orientation disorder in severe moist heat tests and exhibited poor conformability to the substrate. In Comparative Example 5, because it did not contain spherical filler (D), the curable resin composition could not maintain its shape on the substrate for a long time without wetting, spreading, or repelling. In Comparative Example 6, because the amount of spherical filler (D) was large, the encapsulant for film liquid crystal panels obtained by curing the curable resin composition exhibited poor conformability to the substrate. In Comparative Example 7, because the average particle size of the spherical filler (D) was large, the encapsulant for film liquid crystal panels obtained by curing the curable resin composition exhibited poor conformability to the substrate. In Comparative Example 8, because it did not contain a photopolymerization initiator (E), the curable resin composition had low photocurability, and the encapsulant for film liquid crystal panels obtained by curing the curable resin composition suffered from liquid crystal orientation disorder in severe humid heat tests and also had poor conformability to the substrate.

[0072] In Comparative Example 9, because the blending mass ratio (B) / (C) was greater than the specified range, the encapsulant for film liquid crystal panels obtained by curing the curable resin composition suffered from liquid crystal orientation disorder during a severe humid heat test. In Comparative Example 10, because the blending mass ratio (B) / (C) was smaller than the specified range, the curable resin composition had poor liquid crystal contamination resistance, and the encapsulant for film liquid crystal panels obtained by curing the curable resin composition suffered from liquid crystal orientation disorder during a severe humid heat test and also had poor conformability to the substrate.

[0073] In Comparative Example 11, the ratio of the functional group concentration of thiol groups in (A) to the combined functional group concentrations of polymerizable unsaturated bonds in (B) and (C) was greater than the specified range. As a result, the encapsulant for film liquid crystal panels obtained by curing the curable resin composition suffered from liquid crystal orientation disorder during a severe moist heat test and exhibited poor conformability to the substrate after an accelerated temperature change test. In Comparative Example 12, the ratio of the functional group concentration of thiol groups in (A) to the combined functional group concentrations of polymerizable unsaturated bonds in (B) and (C) was smaller than the specified range. As a result, the encapsulant for film liquid crystal panels obtained by curing the curable resin composition suffered from liquid crystal orientation disorder during a severe moist heat test and exhibited poor conformability to the substrate.

[0074] In Comparative Example 13, although the composition contains a polyfunctional (meth)acrylate (component F) as an additional component, the blending mass ratio (B) / (C) is smaller than the specified range. As a result, the curable resin composition has poor liquid crystal contamination resistance, and the encapsulant for film liquid crystal panels obtained by curing the curable resin composition suffers from liquid crystal orientation disorder in severe humid heat tests and also exhibits poor conformability to the substrate. In Comparative Example 14, although the composition contains a surfactant (component G) as an additional component, the blending mass ratio (B) / (C) is larger than the specified range. As a result, the encapsulant for film liquid crystal panels suffers from liquid crystal orientation disorder in severe humid heat tests. In Comparative Example 15, although a silane coupling agent (H) was included as an additional component, the ratio of the functional group concentration of the thiol group (A) to the combined functional group concentrations of the polymerizable unsaturated bonds (B) and (C) was greater than the specified range. As a result, the encapsulant for film liquid crystal panels obtained by curing the curable resin composition suffered from liquid crystal orientation disorder in severe humid heat tests and exhibited poor followability to the substrate after accelerated temperature change tests.

Claims

1. (A) A polyfunctional thiol compound having 2 to 6 thiol groups, (B) A polyfunctional urethane (meth)acrylate compound having 2 to 3 (meth)acrylic groups, (C) A polyfunctional allyl compound having 2 to 4 (meth)allyl groups, (D) Spherical fillers with an average particle diameter of 15 μm or less, (E) Contains a photopolymerization initiator, The combined mass ratio (B) / (C) of (B) and (C) is between 0.1 and 1.

0. The ratio of the functional group concentration of thiol groups in (A) to the total functional group concentration of polymerizable unsaturated bonds in (B) and (C) (thiol groups / polymerizable unsaturated bonds) is 0.5 to 3.

0. A curable resin composition for use as a encapsulant for film liquid crystal panels, wherein (D) is 1 to 50 parts by mass relative to a total of 100 parts by mass of (A), (B), and (C).

2. A film liquid crystal panel having its edges sealed with the curable resin composition described in claim 1.

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