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

Abstract

The present invention addresses the problem of providing a curable resin composition for use in a sealing material for a film liquid crystal panel, the resin composition being stable in a state of being uncured, not experiencing crystal misalignment even under a harsh environment of heat and humidity or under conditions of acidity, and having excellent conformance to a substrate.　In order to solve the problem described above, there is provided a curable resin composition for use in a sealing material for film liquid crystal panel, the composition containing: (A) a polyfunctional thiol compound; (B) a polyfunctional (meth)acrylic compound which has 3-6 (meth)acrylic groups and has a (meth)acrylic equivalent of 100-250; (C) a polyfunctional acrylic compound which has 2-4 (meth)acrylic groups; and (D) a photopolymerization initiator. The blending mass ratio of (B) / (C) is 0.1-1.0, and the ratio between thiol groups of (A) and polymerizable unsaturated bonds of (B) and (C) (thiol groups / polymerizable unsaturated bonds) is 0.5-3.0.

Description

[Technical Field]

[0001] The present invention relates to a curable resin composition for use as an encapsulant for film liquid crystal panels. More specifically, the present invention relates to a curable resin composition that is stable in its uncured state, does not cause orientation disruption of liquid crystals even when the cured product is in contact with liquid crystals under harsh humid and hot environments or acidic conditions, and forms an encapsulant for film liquid crystals that exhibits excellent conformability to the substrate regardless of temperature changes. 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 advantages in terms of workability and productivity, such as immediate curing with light, stability in the uncured state, and no gelation during storage at room temperature or during work, 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 low barrier properties and are prone to decomposition. As a result, in humid and hot environments and acidic conditions, they cause contamination of the liquid crystals by moisture, acid, and encapsulant decomposition products, 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, the sealing material described in Patent Document 1 had the problem that liquid crystal alignment disorder occurred under acidic conditions. 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 lacks flexibility in exchange for its moisture barrier properties, resulting in insufficient conformability to flexible film substrates and a problem where the sealing material peels off the film. Furthermore, because thiol monomers and en monomers are generally highly reactive, the encapsulant described in Patent Document 1 had poor stability in its uncured state, resulting in problems with workability and productivity. [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 is stable in an uncured state, does not cause orientation disorder of liquid crystals even when the cured product is in contact with liquid crystals under harsh humid heat environments or acidic conditions, 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 have diligently conducted research and have discovered that by combining a specific polyfunctional (meth)acrylic compound and a specific polyfunctional (meth)allyl compound, and further using a curable resin composition containing a polyfunctional thiol compound, it is possible to obtain a encapsulant for film liquid crystal panels in which the curable resin composition is stable in the uncured state and 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 or acidic conditions. Furthermore, the inventors have discovered 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] (A) A polyfunctional thiol compound having 2 to 6 thiol groups, (B) A polyfunctional (meth)acrylic compound having 3 to 6 (meth)acrylic groups and a (meth)acrylic equivalent of 100 to 250, (C) A polyfunctional allyl compound having 2 to 4 (meth)allyl groups, (D) Contains a photopolymerization initiator, The combined mass ratio (B) / (C) of (B) and (C) is between 0.1 and 1.0. A curable resin composition for use as a encapsulant for film liquid crystal panels, wherein 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 groups / polymerizable unsaturated bonds) is 0.5 to 3.0. [2] A film liquid crystal panel with its ends sealed using the curable resin composition described in [1] above.

[0010] In the present invention, the "(meth)allyl compound" means a general term including both a compound having an allyl group and a compound having a methallyl group. The same applies to "(meth)acrylic group" and the like. In the present invention, "○○~××" indicating a numerical range means a concept including its lower limit value ("○○") and upper limit value ("××") unless otherwise specified. That is, precisely, it means "○○ or more and ×× or less". [Advantages of the Invention]

[0011] According to the present invention, a curable resin composition can be provided for use as a sealing material for a film liquid crystal panel, which is stable in an uncured state, and in addition, the cured product does not cause disorder in the liquid crystal alignment even when in contact with the liquid crystal under severe humid heat environment or acidic conditions, and has excellent followability to the substrate regardless of changes in the temperature environment. Further, a film liquid crystal panel using the above curable resin composition as a sealing material can be provided. [Modes for Carrying Out the Invention]

[0012] The curable resin composition of the present invention, which is used as a sealing material for a film liquid crystal panel, contains the following (A), (B), (C), and (D) as essential components.

[0013] <省 [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 base material of the encapsulant. In addition, the cured product composed of thioether bonds has a highly flexible bond angle and can be cured at a high density so that atoms fill the gaps between bonds. Therefore, it has high barrier properties against moisture and acids and can prevent the alignment disorder of liquid crystals even under severe damp heat tests or acidic conditions.

[0014] The polyfunctional thiol compound (A) is preferably a compound represented by the following formula 1. [Chemical formula] (In the formula, a is an integer of 2 to 6, and R 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 barrier properties of the encapsulant for the film liquid crystal panel against moisture and acids and suppressing the alignment disorder of liquid crystals even under severe damp heat tests or acidic conditions, a is preferably an integer of 3 to 6. If a in the formula is within this range, a large curing shrinkage does not occur and the followability to the base material after curing does not decrease, and a good cured product can be obtained. Also, from the same viewpoint, R 1 is preferably trivalent to hexavalent. The number of carbon atoms of R 1 is 10 to 60, preferably 10 to 45, and more preferably 12 to 30. If the number of carbon atoms of R 1 is within this range, the crosslink density of the cured product of the curable resin composition is sufficient, the encapsulant has excellent barrier properties against moisture and acids, and can suppress the alignment disorder of liquid crystals even under severe damp heat tests or acidic conditions.

[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-mercaptopropiomoloxy)-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 barrier properties of the encapsulant against moisture and acid, suppress orientation disorder of the liquid crystal even under harsh humid heat testing and acidic conditions, and increase the flexibility of the cured product of the curable resin composition, thereby improving the conformability of the encapsulant to the substrate.

[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 (meth)acrylic compound (B)> Polyfunctional (meth)acrylic compound (B) is a compound having 3 to 6 (meth)acrylic groups and a (meth)acrylic equivalent of 100 to 250. The (meth)acrylic equivalent is the molecular weight divided by the number of (meth)acrylic groups contained. Polyfunctional (meth)acrylic compound (B) can be used alone or in combination of two or more types. By including polyfunctional (meth)acrylic compound (B), the cured product of the curable resin composition can be given appropriate flexibility and polarity, and the conformability of the encapsulant to the substrate can be improved regardless of changes in the temperature environment. Furthermore, polyfunctional thiol compound (A) and polyfunctional (meth)allyl compound (C) are highly reactive, and the uncured product of a curable resin composition containing these is unstable and difficult to use. However, by coexisting with polyfunctional (meth)acrylic compound (B), the reactivity can be suppressed, thereby increasing the stability of the uncured product of the curable resin composition and improving its usability.

[0020] From the perspective that the (meth)acrylic equivalent of the polyfunctional (meth)acrylic compound (B) can enhance the followability of the sealing material to the base material regardless of the change in temperature environment while maintaining the flexibility of the cured product of the curable resin composition and the barrier properties against moisture and acids, it is preferably 120 to 200.

[0021] The polyfunctional (meth)acrylic compound (B) is preferably a compound represented by the following formula 2. [Chemical formula] (In the formula, b is an integer from 3 to 6. R 2 is a hydrogen atom or a methyl group. R 3 is an organic group with a valence of 3 to 6 and a carbon number of 5 to 70.) In the formula, R 2 is a hydrogen atom or a methyl group, and from the perspective 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 preferred. b is an integer from 3 to 6, and within this range, while maintaining the flexibility of the cured product of the curable resin composition and the barrier properties against moisture and acids, the followability of the sealing material to the base material can be enhanced regardless of the change in temperature environment. Furthermore, the stability of the uncured product of the curable resin composition can be increased and the usability can be improved. Also, R 3 is also trivalent to hexavalent from the same perspective. The carbon number of R 3 is 5 to 70, preferably 5 to 60, and more preferably 5 to 50. If the carbon number of R 3 is within this range, while maintaining the flexibility of the cured product of the curable resin composition and the barrier properties against moisture and acids, the followability of the sealing material to the base material can be enhanced regardless of the change in temperature environment.

[0022] 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 a repeating unit. Also, the structure may contain groups such as a ketone group, an ester group, an ether group, a hydroxyl group, an amide group, a thioether group, and an isocyanurate group.

[0023] Examples of polyfunctional (meth)acrylic compounds where b is 3 include trimethylolpropane trimethacrylate, ethylene oxide-modified trimethylolpropane tri(meth)methacrylate, propylene oxide-modified trimethylolpropane tri(meth)methacrylate, caprolactone-modified trimethylolpropane tri(meth)acrylate, ethylene oxide-modified glycerol tri(meth)acrylate, propylene oxide-modified glycerol tri(meth)acrylate, pentaerythritol trimethacrylate, ethoxylated isocyanuric acid tri(meth)acrylate, ethylene oxide-modified isocyanuric acid tri(meth)acrylate, propylene oxide-modified isocyanuric acid tri(meth)acrylate, and caprolactone-modified isocyanuric acid tri(meth)acrylate. Examples of polyfunctional (meth)acrylic compounds where b is 4 include ditrimethylolpropanetetra(meth)acrylate, ethylene oxide-modified ditrimethylolpropanetetra(meth)acrylate, propylene oxide-modified ditrimethylolpropanetetra(meth)acrylate, caprolactone-modified ditrimethylolpropanetetra(meth)acrylate, pentaerythritol tetramethacrylate, ethylene oxide-modified pentaerythritol tetra(meth)acrylate, propylene oxide-modified pentaerythritol tetra(meth)acrylate, and caprolactone-modified pentaerythritol tetra(meth)acrylate. Examples of polyfunctional (meth)acrylic compounds with b = 5 to 6 include dipentaerythritol hydroxypenta(meth)acrylate, ethylene oxide-modified dipentaerythritol hexa(meth)acrylate, propylene oxide-modified dipentaerythritol hexa(meth)acrylate, caprolactone-modified dipentaerythritol hexa(meth)acrylate, alkyl-modified dipentaerythritol hexa(meth)acrylate, and others. Among the above-mentioned polyfunctional (meth)acrylic compounds, (meth)acrylic compounds having an isocyanurate skeleton, (meth)acrylic compounds having a dipentaerythritol skeleton, and (meth)acrylic compounds having a pentaerythritol skeleton are preferred from the viewpoint of being able to improve the conformability of the encapsulant to the substrate regardless of changes in the temperature environment while maintaining the flexibility and barrier properties from moisture and acid of the cured product of the curable resin composition. Specifically, ethoxylated isocyanuric acid tri(meth)acrylate, ethylene oxide-modified isocyanuric acid tri(meth)acrylate, ethylene oxide-modified dipentaerythritol hexa(meth)acrylate, propylene oxide-modified dipentaerythritol hexa(meth)acrylate, and caprolactone-modified dipentaerythritol hexa(meth)acrylate are preferred.

[0024] <Polyfunctional (meth)allyl compound (C)> Polyfunctional allyl compounds (C) are compounds having 2 to 4 (meth)allyl groups. Polyfunctional allyl compounds (C) can be used alone or in combination of two or more. Because (C) is difficult to polymerize on its own, it excels at forming crosslinked networks with other components, increasing the toughness of the cured product of the curable resin composition and improving the conformability of the encapsulant to the substrate. It also enhances barrier properties against moisture and acid, preventing liquid crystal orientation disorder even under harsh humid heat testing or acidic conditions. The polyfunctional allyl compound (C) is preferably a compound represented by the following formula 3. [ka] (In the formula, c is an integer between 2 and 4. R 4 R is a hydrogen atom or a methyl group. 5 (It is a divalent to tetravalent organic group with 2 to 40 carbon atoms.) R in the formula 4c is a hydrogen atom or a methyl group, and a hydrogen atom is preferred from the viewpoint of increasing the flexibility of the cured product of the curable resin composition and improving the conformability of the encapsulant to the substrate. c is an integer from 2 to 4, and being within this range enhances the barrier properties of the encapsulant from moisture and acid, preventing disorder of liquid crystal orientation even under harsh humid heat tests and acidic conditions. Furthermore, the flexibility of the cured product of the curable resin composition is increased, improving the conformability of the encapsulant to the substrate. Also, R 5 From a similar perspective, R is 2-4 valent. 5 The number of carbon atoms is 2 to 40, preferably 2 to 30, and more preferably 2 to 25. 5 If the number of carbon atoms is within this range, the crosslinking density of the cured product of the curable resin composition is sufficient, and the encapsulant has high barrier properties against moisture and acid, so orientation disorder can be suppressed even under harsh humid heat testing or acidic conditions.

[0025] 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.

[0026] For example, specific examples of compounds in which c 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 c is 3 include triallyl isocyanurate, pentaerythritol tri(meth)allyl ether, glycerin tri(meth)allyl ether, and trimethylolpropane triallyl ether. Examples of compounds where c 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 enhancing the barrier properties of the encapsulant from moisture and acid, suppressing orientation disorder even under harsh moist heat tests and acidic conditions, and also 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.

[0027] <Photopolymerization initiator (D)> Photopolymerization initiator (D) is added to promote the photo-curing reaction of polymerizable compounds when polymerizable compounds such as (A), (B), (C), and others are added, 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 usability.

[0028] 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).

[0029] 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.

[0030] 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.

[0031] <Polyfunctional urethane (meth)acrylate (E)> The curable resin composition of the present invention may contain a polyfunctional urethane (meth)acrylate (E) to the extent that it does not hinder the objectives of the present invention. The polyfunctional urethane (meth)acrylate (E) is obtained by reacting a diisocyanate compound, a polyol compound, and a (meth)acrylate compound having a hydroxyl group by known methods. The polyfunctional urethane (meth)acrylate (E) may be used alone or in combination of two or more types. By including such compounds, the cured product of the curable resin composition can be strengthened, and the conformability of the encapsulant to the substrate can be further improved. In addition, the urethane groups contained can exhibit strong interactions such as hydrogen bonding with each other and with other polar groups from low to high temperatures, so the cured product of the curable resin composition is strengthened regardless of the temperature environment, and the conformability of the encapsulant to the substrate can be further improved. Polyfunctional urethane (meth)acrylate (E) 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] The weight-average molecular weight of the polyfunctional urethane (meth)acrylate (E) is preferably 1,000 to 15,000, from the viewpoint of the encapsulant maintaining barrier properties against moisture and acid, having high conformability to the substrate regardless of the temperature environment, and 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.

[0040] The content of polyfunctional urethane (meth)acrylate (E) in the curable resin composition of the present invention is 0 to 20 parts by mass, preferably 1 to 15 parts by mass, based on 100 parts by mass of the total of (A), (B), and (C).

[0041] <Surfactant (F)> The curable resin composition of the present invention may contain a surfactant (F) to the extent that it does not hinder the objectives of the present invention. Because surfactant (F) has high hydrophobicity, its inclusion in the curable resin composition improves the moisture barrier properties of the encapsulant, and further suppresses liquid crystal orientation disorder even when exposed to harsh moist heat tests or acidic conditions. Known silicone-based surfactants, fluorine-based surfactants, acrylic-based surfactants, etc., can be used as surfactant (F) 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.

[0042] The amount of surfactant (F) in the curable resin composition of the present invention is 0 to 3 parts by mass, preferably 0.01 to 1 part by mass, based on 100 parts by mass of the total of (A), (B), and (C).

[0043] <Silane coupling agent (G)> The curable resin composition of the present invention may contain a silane coupling agent (G) to the extent that it does not hinder the objectives of the present invention. The silane coupling agent (G) 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 due to bleed-out and causing disorder of liquid crystal orientation when the encapsulant is used for a long period of time, 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.

[0044] The content of the silane coupling agent (G) in the curable resin composition of the present invention is 0 to 15 parts by mass, preferably 1 to 10 parts by mass, based on 100 parts by mass of the total of (A), (B), and (C).

[0045] <Other ingredients> The curable resin composition of the present invention may contain, in addition to the above-mentioned polyfunctional urethane (meth)acrylate (E), surfactant (F), and silane coupling agent (G), other additives such as epoxy compounds, curing accelerators, ultraviolet absorbers, light stabilizers, antioxidants, polymerization inhibitors, leveling agents, adhesion promoters, plasticizers, defoamers, fillers, light shielding materials, conductive materials, and spacers, to the extent that they do not hinder the objectives of the present invention.

[0046] <Composition ratio (mixing ratio)> 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 (meth)acrylic compound (B) and the polyfunctional (meth)allyl compound (C), yielding a cured product. The formed thioether bonds can flexibly change their bond angles, thereby increasing the flexibility of the cured product of the curable resin composition. Furthermore, because the atoms can harden to a high density, filling the gaps between bonds, the barrier properties against moisture and acids can be enhanced. Since the polyfunctional (meth)allyl compound (C) does not polymerize on its own, the inclusion of the polyfunctional (meth)allyl compound (C) allows for efficient formation of thioether bonds, resulting in a flexible and tough cured product. In addition, the crosslinking density is improved, further enhancing the barrier properties. The encapsulant exhibits excellent conformability to the substrate and can prevent disruption of liquid crystal orientation even when in contact with liquid crystals under harsh humid and hot environments or acidic conditions. Furthermore, the polyfunctional (meth)acrylic compound (B) suppresses the reactivity between the polyfunctional thiol compound (A) and the polyfunctional (meth)allyl compound (C), increasing the stability of the uncured product of the curable resin composition and improving its usability. In addition, the polyfunctional (meth)acrylic compound (B) imparts appropriate flexibility and polarity to the cured product of the curable resin composition, improving the conformability of the encapsulant to the substrate regardless of temperature changes. Thus, in order for the curable resin composition of the present invention to be stable in the uncured state, and for the encapsulant made from the cured product to not cause disorder of liquid crystal orientation even when in contact with liquid crystal under harsh humid and hot environments or acidic conditions, and to have excellent conformability to the substrate regardless of temperature changes, all of (A), (B), and (C) are indispensable. Moreover, by further using (D) in a curable resin composition containing (A), (B), and (C), the above effects can be achieved by curing with 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 them so that the sum of the functional group concentration of the thiol group in (A) and the functional group concentrations of the polymerizable unsaturated bonds in (B) and (C) (thiol group / polymerizable unsaturated bond) is 0.5 to 3.0, the curable resin composition is stable in its uncured state, and the resulting encapsulant does not cause disorder of liquid crystal orientation even when in contact with liquid crystal under harsh humid and hot environments or acidic conditions, and exhibits excellent conformability to the substrate regardless of changes in temperature. 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].

[0047] In the curable resin composition of the present invention, in order for the curable resin composition to have excellent stability in the uncured state and to further improve usability, the mixing mass ratio of (B) and (C), (B) / (C), is 0.2 to 1.0. In order to improve the toughness of the cured product of the curable resin composition and to further enhance the conformability of the encapsulant to the substrate, as well as to impart appropriate flexibility and polarity to the cured product and to further enhance the conformability of the encapsulant to the substrate regardless of changes in the temperature environment, the mixing mass ratio of (B) and (C), (B) / (C), is 0.2 to 0.9. To enhance the barrier properties of materials against moisture and acid, and to further prevent liquid crystal orientation disorder even under harsh humid heat testing or acidic conditions, the blending mass ratio (B) / (C) of (B) to (C) is preferably 0.1 to 0.8. In other words, to achieve a higher level of performance in conjunction with the high usability of the curable resin composition, the high conformability of the encapsulant to the substrate regardless of temperature changes, and the ability of the encapsulant to prevent liquid crystal orientation disorder even under harsh humid heat testing or acidic conditions, the blending mass ratio (B) / (C) of (B) to (C) is preferably 0.2 to 0.8.

[0048] Furthermore, in the curable resin composition of the present invention, in order to enhance the toughness of the cured product of the curable resin composition and to further improve the conformability of the encapsulant to the substrate, it is preferable that 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 group / polymerizable unsaturated bond) is 0.7 to 3.0. In order to maintain the flexibility and toughness of the cured product of the curable resin composition from low to high temperatures and to further improve the conformability of the encapsulant to the substrate regardless of changes in the temperature environment, it is preferable that 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 group / polymerizable unsaturated bond) is 0.7 to 2.8. In order to enhance the barrier properties of the cured product against moisture and acid, and to further prevent liquid crystal orientation disorder even under harsh humid heat testing or acidic conditions, it is preferable that 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 group / polymerizable unsaturated bond) be 0.5 to 2.6. In other words, in order to achieve higher levels of performance in conjunction with the ability of the encapsulant to follow the substrate regardless of temperature changes, and to prevent liquid crystal orientation disorder even under harsh humid heat testing or acidic conditions, it is preferable that 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 group / polymerizable unsaturated bond) be 0.7 to 2.6.

[0049] Furthermore, in the curable resin composition of the present invention, the ratio of (D) 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 (D) within the above range, it is possible to obtain a sealing material that does not cause disorder of liquid crystal orientation even when in contact with liquid crystal under harsh humid and hot environments or acidic conditions, and that exhibits excellent conformability to the substrate regardless of changes in the temperature environment.

[0050] <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 members 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.

[0051] <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, then placing the other substrate on top of it with liquid crystal interposed inside, 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 of it, 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.

[0052] 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.

[0053] <Stability of curable resin compositions> The curable resin compositions prepared in the examples and comparative examples were added to sample bottles and left to stand at 25°C under light shielding. Every day, the sample bottles were tilted at a 45°C angle in a 25°C environment illuminated by a yellow lamp that did not emit light with wavelengths below 500 nm. After 5 minutes, the state of the curable resin composition in the bottle was observed, and the time until the fluidity of the curable resin composition disappeared and gelled was confirmed. In the above observation, the curable resin composition was determined to have gelled if its shape did not change according to the tilt of the bottle. Note that a longer time to gel indicates higher stability, and the time to gel is indicated in each table. ◎: Does not gel for more than 7 days. ○: It gels in 4 to 6 days. ×: It will gel within 3 days.

[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. 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 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] <Orientation disruption after harsh humid and hot environments> 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. 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 fabricated liquid crystal panel was exposed to 60°C and 95%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 using 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 0.4 mm from the edge of the sealing material. ○: Orientation disorder extends beyond 0.4 mm from the edge of the sealing material, but does not extend beyond 0.8 mm. ×: The orientation disorder extends beyond 0.8 mm from the edge of the sealing material.

[0057] <Orientation disorder after acidic condition testing> 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. Ultraviolet irradiation (1000mJ / cm²) was performed using a high-pressure mercury lamp. 2A liquid crystal panel was obtained by performing the following procedure. The fabricated liquid crystal panel was mounted on a CYP-90A combined cycle tester manufactured by Suga Test Instruments Co., Ltd. Artificial acid rain was prepared by adding nitric acid, sulfuric acid, and a 10% sodium hydroxide solution to a 5% sodium chloride aqueous solution to adjust the pH to 3.5. The panel was subjected to a cycle of (30 minutes of spraying the artificial acid rain at 30°C and 98% humidity, followed by 90 minutes of wetting at 30°C and 95% humidity, followed by 2 hours of drying at 50°C and 20% humidity, followed by 2 hours of drying at 30°C and 20% humidity) 10 times. After that, it was driven at an AC 5V voltage in a medium tone display state, and the orientation disorder of the liquid crystal 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 0.4 mm from the edge of the sealing material. ○: Orientation disorder extends beyond 0.4 mm from the edge of the sealing material, but does not extend beyond 0.8 mm. ×: The orientation disorder extends beyond 0.8 mm from the edge of the sealing material.

[0058] <Polyfunctional thiol compound (A)> A-1: Dipentaerythritol hexakis (3-mercaptopropionate) [Number of thiol groups: 6, Molecular weight: 783.0] A-2: Pentaerythritol tetrakis(3-mercaptopropionate) [Number of thiol groups: 4, Molecular weight: 488.6] A-3: Tris-[(3-mercaptopropiomoloxy)-ethyl]-isocyanurate [Number of thiol groups: 3, Molecular weight: 525.6]

[0059] <Polyfunctional (meth)acrylic compound (B)> B-1: Ethoxylated isocyanuric acid triacrylate [Number of acrylic groups: 3, Acrylic equivalent: 141, Molecular weight: 423.0] B-2: Trimethylolpropane trimethacrylate [Number of methacrylate groups: 3, Methacrylate equivalent: 113, Molecular weight: 338.0] B-3: Caprolactone-modified dipentaerythritol hexaacrylate [Number of acrylic groups: 6, Acrylic equivalent weight: 131, Molecular weight: 783.0] B-4: Caprolactone-modified ditrimethylolpropanetetraacrylate [Number of acrylic groups: 4, Acrylic equivalent: 231, Molecular weight: 922.5] B-5: Dipropylene glycol diacrylate [Number of acrylic groups: 2, Acrylic equivalent: 121, Molecular weight: 242.0] B-6: Pentaerythritol tetraacrylate [Number of acrylic groups: 4, Acrylic equivalent: 88, Molecular weight: 352.0] B-7: Propylene oxide-modified trimethylolpropane triacrylate [Number of acrylic groups: 3, Acrylic equivalent: 261, Molecular weight: 783.0]

[0060] <Polyfunctional (meth)allyl compound (C)> C-1: 1,3-diallyl-5-glycidyl isocyanurate [Number of allyl groups: 2, Molecular weight: 265.3] C-2: Triallyl isocyanurate [Number of allyl groups: 3, Molecular weight: 249.7] C-3: Pentaerythritol tetraallyl ether [Number of allyl groups: 4, Molecular weight: 296.4] C-4: Ethylene glycol monoallyl AL [Number of allyl groups: 1, Molecular weight: 102.1]

[0061] <Photopolymerization initiator (D)> D-1: Bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide D-2: 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3yl]ethanone-1-(O-acetyloxime) D-3: 1-Hydroxycyclohexylphenyl ketone

[0062] <Polyfunctional urethane (meth)acrylate (E)> [Synthesis of urethane (meth)acrylate (E-1)] In a reaction vessel equipped with a stirrer, reflux condenser, nitrogen inlet tube, and thermometer, 9.7 parts by mass of glycerin were charged, and stirring was started. Next, 0.1 parts by mass of dibutyltin laurate and 88.2 parts by mass of isophorone diisocyanate were added, and the internal temperature was raised to 80°C while paying attention to the exothermic reaction. The mixture was then stirred for 3 hours while maintaining the temperature. Furthermore, 0.1 parts by mass of methoquinone as a polymerization inhibitor and 41.8 parts by mass of propylene glycol monoacrylate 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 (E-1) (weight-average molecular weight: 7,500).

[0063] [Synthesis of polyol compound (e-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 (e-1) (weight-average molecular weight: 1,000).

[0064] [Synthesis of urethane (meth)acrylate (E-2)] In a reaction vessel equipped with a stirrer, reflux condenser, nitrogen inlet tube, and thermometer, 101.1 parts by mass of polyol compound (e-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 (E-2) (weight-average molecular weight: 3,000).

[0065] <Surfactant (F)> F-1: Megafuck F-554, manufactured by DIC Corporation. F-2: Megafuck F-477, manufactured by DIC Corporation.

[0066] <Silane coupling agent (G)> G-1:3-Methacryloxypropyltrimethoxysilane G-2:3-mercaptopropyltrimethoxysilane

[0067] [Examples 1-20, Comparative Examples 1-15] The above components were added to a stirring vessel in the proportions shown in Tables 1-1, 1-2, 2-1, and 2-2 below, and mixed and stirred for 2 hours to obtain 1 kg of curable resin composition. The curable resin composition was used for various evaluations. The results are shown in the respective tables.

[0068] [Table 1-1]

[0069] [Table 1-2]

[0070] [Table 2-1]

[0071] [Table 2-2]

[0072] The results of the above tests showed that the curable resin compositions of each example, by containing appropriate amounts of components (A) to (D) as defined in the present invention, had high stability in the uncured product, the cured product had high conformability to the substrate regardless of the temperature environment, and furthermore, did not undergo liquid crystal orientation disorder after the humid heat test and the acidic condition test.

[0073] On the other hand, in Comparative Example 1, because it did not contain the polyfunctional thiol compound (A), the encapsulant for film liquid crystal panels obtained by curing the curable resin composition had poor conformability to the substrate and suffered from liquid crystal orientation disorder in harsh humid heat tests and acidic condition tests. In Comparative Example 2, because it did not contain the polyfunctional (meth)acrylic compound (B), the curable resin composition had low stability, and the encapsulant for film liquid crystal panels obtained by curing the curable resin composition 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 had poor conformability to the substrate and suffered from liquid crystal orientation disorder in harsh humid heat tests and acidic condition tests. In Comparative Example 4, because it did not contain a photopolymerization initiator (D), the encapsulant for film liquid crystal panels obtained by curing the curable resin composition had poor conformability to the substrate and suffered from liquid crystal orientation disorder during harsh humid heat tests and acidic condition tests.

[0074] In Comparative Example 5, because the polyfunctional (meth)acrylic compound (B) had a small number of functional groups, the encapsulant for film liquid crystal panels obtained by curing the curable resin composition exhibited poor conformability to the substrate after the accelerated temperature change test. In Comparative Example 6, because the (meth)acrylic equivalent of the polyfunctional (meth)acrylic compound (B) was small, the encapsulant for film liquid crystal panels obtained by curing the curable resin composition exhibited poor conformability to the substrate after the accelerated temperature change test. In Comparative Example 7, because the (meth)acrylic equivalent of the polyfunctional (meth)acrylic compound (B) was large, the encapsulant for film liquid crystal panels obtained by curing the curable resin composition suffered from liquid crystal orientation disorder in the acidic condition test.

[0075] In Comparative Example 8, the blending mass ratio (B) / (C) was greater than the specified range, resulting in poor conformability to the substrate and causing liquid crystal orientation disruption during harsh humid heat and acidic condition tests. In Comparative Example 9, the blending mass ratio (B) / (C) was smaller than the specified range, resulting in low stability of the curable resin composition and poor conformability to the substrate of the encapsulant for film liquid crystal panels obtained by curing the curable resin composition.

[0076] In Comparative Example 10, the ratio of the functional group concentration of the thiol group in (A) to the combined functional group concentrations of the 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 exhibited poor conformability to the substrate after accelerated temperature change tests, and also suffered from liquid crystal orientation disorder in harsh humid heat tests and acidic condition tests. In Comparative Example 11, the ratio of the functional group concentration of the thiol group in (A) to the combined functional group concentrations of the 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 also exhibited poor conformability to the substrate.

[0077] In Comparative Example 12, 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 had poor conformability to the substrate and suffered from liquid crystal orientation disorder in harsh humid heat tests and acidic condition tests. In Comparative Example 13, because the amount of photopolymerization initiator (D) was large, the encapsulant for film liquid crystal panels obtained by curing the curable resin composition suffered from liquid crystal orientation disorder in harsh humid heat tests and acidic condition tests.

[0078] In Comparative Example 14, although the compounding mass ratio (B) / (C) contained polyfunctional urethane (meth)acrylate as an additional component, the curable resin composition had low stability because the blending mass ratio (B) / (C) was smaller than the specified range. Furthermore, the encapsulant for film liquid crystal panels obtained by curing the curable resin composition had poor conformability to the substrate. In Comparative Example 15, although the compounding mass contained surfactant as an additional component, 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 larger than the specified range. As a result, the encapsulant for film liquid crystal panels obtained by curing the curable resin composition had poor conformability to the substrate after accelerated temperature change tests, and also suffered from liquid crystal orientation disorder in harsh humid heat tests and acidic condition tests. In Comparative Example 16, although the silane coupling agent component (G) was included as an additional component, the ratio of the functional group concentration of the thiol group (A) to the total functional group concentrations of the polymerizable unsaturated bonds (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 had poor conformability to the substrate.

Claims

1. (A) Polyfunctional thiol compounds having 2 to 6 thiol groups, (B) A polyfunctional (meth)acrylic compound having 3 to 6 (meth)acrylic groups and a (meth)acrylic equivalent of 100 to 250. (C) A polyfunctional allyl compound having 2 to 4 (meth)allyl groups, (D) Photopolymerization initiator, It contains, The combined mass ratio (B) / (C) of (B) and (C) is between 0.1 and 1.

0. A curable resin composition for use as a encapsulant for film liquid crystal panels, wherein 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 groups / polymerizable unsaturated bonds) is 0.5 to 3.

0.

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

Images