Polymerizable compound, curable resin composition, and sealing agent for display element

Abstract

The present invention provides: a polymerizable compound which has high viscosity and provides a cured product having excellent transparency; a curable resin composition which contains the polymerizable compound; and a sealing agent for a display element, which is composed of the curable resin composition. This polymerizable compound is represented by formula (1u). In the formula (1u), au represents an integer of 0 or more; Ru each independently represents an organic group having 2 to 10 carbon atoms; at least one Ru has an alkylene glycol skeleton in which the number of repetitions of alkylene units having 2 to 6 carbon atoms is 1 or more; at least one Ru represents an organic group having a hydrogen-bonding polar functional group; R1u and R2u each independently represent an organic group having 2 to 10 carbon atoms; and Xu represents an organic group.

Description

Polymerizable compounds, curable resin compositions, and encapsulants for display elements

[0001] This invention relates to polymerizable compounds. Furthermore, this invention relates to a curable resin composition containing a polymerizable compound, and a encapsulant for display elements comprising the curable resin composition.

[0002] In recent years, liquid crystal displays and organic EL displays have been widely used as display elements that are thin, lightweight, and have low power consumption. For example, a liquid crystal display is usually manufactured by placing two transparent substrates with electrodes opposite each other at a predetermined distance apart, sealing the periphery with a sealant to form a cell, and injecting liquid crystal into the cell through a liquid crystal injection port provided in a part of the cell. Curable resin compositions containing polymerizable compounds are used for sealing liquid crystals in this way.

[0003] As a technology relating to curable resin compositions, for example, Patent Document 1 discloses a photocurable adhesive for polarizing plates that contains a polythiol compound having two or more thiol groups in one molecule, a polyene compound having two or more carbon-carbon double bonds in one molecule, and a photopolymerization initiator.

[0004] Patent Document 2 contains a polythiol monomer having two or more thiol groups in one molecule, a polyene monomer having two or more carbon-carbon double bonds in one molecule, and a photopolymerization initiator, with a volume resistivity of 5.0 × 10 at 30°C. １０ A encapsulant for display elements is disclosed, having a viscosity of Ω or more, and a viscosity of 0.4 to 8 Pa·s measured using a cone-rotor viscometer at 20°C and 20 rpm.

[0005] Patent Document 3 discloses a photocurable resin composition comprising a polyene compound having two or more carbon-carbon double bonds in one molecule, a polythiol compound having two or more thiol groups in one molecule, and a photopolymerization initiator, wherein the acid value is 3 or less.

[0006] Patent Document 4 discloses a crosslinked coating film obtained by crosslinking a crosslinkable resin composition, wherein the crosslinked coating film has a glass transition temperature of -30 to 60°C, a storage modulus in a dynamic viscoelasticity test of 0.1 to 1,000 MPa in the range of -30 to -10°C and 0.01 to 5 MPa in the range of 80 to 150°C, and an elongation of 30% or more in an atmosphere of 25°C.

[0007] Japanese Patent Publication No. 2005-139401, Japanese Patent Publication No. 2016-074784, Japanese Patent Publication No. Hei 6-306172, International Publication No. 2017 / 056141

[0008] In recent years, with the widespread adoption of foldable smartphones, it has become necessary for the encapsulant itself to not crack or peel when bent. Furthermore, considering the application process of the encapsulant, a high-viscosity encapsulant is required. Although curable resin compositions described in Patent Documents 1 to 4 were known, there was room for improvement in increasing the viscosity of the encapsulant and further enhancing the bending resistance of the cured encapsulant. In addition, in display elements, impact resistance and other properties are ensured by applying the encapsulant on an optical film or the like. Considering its application to optical uses, it is desirable that the encapsulant be transparent when cured. Although curable resin compositions described in Patent Documents 1 to 4 were known, there was room for improvement in obtaining a cured product with excellent transparency. The present invention aims to provide a polymerizable compound that is highly viscous and has excellent transparency in its cured product, a curable resin composition containing the polymerizable compound, and a encapsulant for display elements made from the curable resin composition.

[0009] Disclosure 1 is a polymerizable compound represented by the following formula (1u).

[0010]

[0011] In formula (1u), a ｕ represents a non-negative integer, R ｕ Each of these independently represents an organic group having 2 to 10 carbon atoms, and at least one R ｕ It has an alkylene glycol skeleton in which the number of repeating alkylene units having 2 to 6 carbon atoms is 1 or more, and at least one R ｕrepresents an organic group having a hydrogen-bonding polar functional group, and R １ｕ and R ２ｕ each independently represent an organic group having 2 to 10 carbon atoms, and X ｕ represents an organic group. The present disclosure 2 is the polymerizable compound according to the present disclosure 1, wherein in the above formula (1u), the number of carbon atoms in the alkylene unit contained in the alkylene glycol skeleton of R ｕ is 3 or 4. The present disclosure 3 is the polymerizable compound according to the present disclosure 1 or 2, wherein in the above formula (1u), at least one R ｕ has a structure represented by the following formula (2u).

[0012]

[0013] In formula (2u), * represents a bonding site.

[0014] The present disclosure 4 is the polymerizable compound according to any one of the present disclosures 1, 2 or 3, wherein in the above formula (1u), at least one R ｕ has a structure represented by the following formula (3u).

[0015]

[0016] In formula (3u), * represents a bonding site, k ｕ represents 1 or 2, m ｕ represents 0, 1 or 2, n ｕ represents 0, 1 or 2, and m ｕ and n ｕ are not both 0. The present disclosure 5 is a curable resin composition containing the polymerizable compound according to any one of the present disclosures 1, 2, 3 and 4. The present disclosure 6 is the curable resin composition according to the present disclosure 5, further containing a polythiol compound having a plurality of thiol groups in one molecule and a polymerization initiator. The present disclosure 7 is characterized in that, the storage elastic modulus at -20°C of a cured product obtained by applying the curable resin composition onto a substrate to a thickness of 500 µm and irradiating with light having a wavelength of 365 nm and an illuminance of 100 mW / cm ２ for 30 seconds is 500 MPa or less; when the curable resin composition is applied onto a substrate to a thickness of 50 µm and irradiated with light having a wavelength of 365 nm and an illuminance of 100 mW / cm ２The curable resin composition according to disclosure 5 or 6 has a haze value of 5% or less when cured by irradiation with light for 30 seconds. Disclosure 8 is a encapsulant for display elements made from the curable resin composition according to disclosure 5, 6 or 7. The present invention will be described in detail below.

[0017] The inventors focused on polymerizable compounds to be included in a curable resin composition in order to obtain a cured product with excellent transparency, and investigated the chemical structure of such polymerizable compounds. As a result, they found that by using a polymerizable compound having a specific chemical structure, the flexibility of the cured product can be increased and phase separation due to aggregation in the composition can be suppressed, thereby obtaining a cured product with excellent transparency, and thus completed the present invention.

[0018] The polymerizable compounds of this disclosure are represented by the following formula (1u), and are also called polyene monomers or polyene compounds.

[0019]

[0020] In formula (1u), a ｕ represents a non-negative integer, R ｕ Each of these independently represents an organic group having 2 to 10 carbon atoms, and at least one R ｕ It has an alkylene glycol skeleton in which the number of repeating alkylene units having 2 to 6 carbon atoms is 1 or more, and at least one R ｕ R represents an organic group having a hydrogen-bonding polar functional group. １ｕ and R ２ｕ Each of these independently represents an organic group with 2 to 10 carbon atoms, X ｕ represents an organic group.

[0021] Conventional urethane allyl compounds may undergo reaction-induced phase separation during curing, resulting in cloudiness. In contrast, the polymerizable compounds of this disclosure, possessing a novel urethane allyl structure with hydrogen-bonding polar functional groups, effectively suppress phase separation due to aggregation of the urethane skeleton, thus maintaining transparency after curing. In other words, a cured product with excellent transparency (reduced haze) can be obtained. Therefore, the polymerizable compounds of this disclosure are particularly suitable for applications requiring optical transparency.

[0022] Furthermore, since the polymerizable compound represented by formula (1u) is a urethane allyl compound having the alkylene glycol skeleton, the cured product has high bending resistance. Thus, because the polymerizable compound of this disclosure has high bending resistance (flexibility) in the cured product, it can be suitably used as a peripheral sealing agent for the housing of foldable smartphones and the like.

[0023] Furthermore, considering the coating process such as dispensing, a viscosity of several hundred mPa·s or higher is preferable for encapsulants for display elements. However, it has been difficult to achieve high viscosity while maintaining high bending resistance with conventional encapsulants for display elements. On the other hand, as described above, the polymerizable compound of this disclosure achieves high bending resistance and transparency in the cured product, while the viscosity and reactivity of the polymerizable compound can be increased by the allyl groups located at both ends of the main chain.

[0024] In formula (1u), a ｕ The lower limit is 0. ｕ By having a value greater than or equal to 0, high viscosity and high cohesive force derived from the urethane skeleton can be achieved. ｕ The preferred lower limit of is 1, and the more preferred lower limit is 3. In equation (1u), a ｕ The preferred upper limit is 30. ｕ By having an integer less than or equal to 30, the compatibility between the polymerizable compound and other resins can be improved. ｕ A more preferable upper limit is 20, and an even more preferable upper limit is 10.

[0025] In formula (1u), R ｕ Each of these independently represents an organic group having 2 to 10 carbon atoms. By having a lower limit of 2 carbon atoms in the organic group, a high cohesive force derived from the urethane skeleton of the main chain can be expressed. A preferred lower limit for the number of carbon atoms in the organic group is 3, and a more preferred lower limit is 5. Furthermore, by having an upper limit of 10 carbon atoms in the organic group, phase separation can be suppressed, and a transparent liquid state can be maintained. A preferred upper limit for the number of carbon atoms in the organic group is 9, and a more preferred upper limit is 8.

[0026] R ｕThe above-mentioned organic group having 2 to 10 carbon atoms, represented by the above, preferably contains an alkylene group. Examples include a group having one or more constituent units of polyether, a group having one or more constituent units of polypropylene, a group having one or more constituent units of polytetramethylene ether, a group having one or more constituent units of polyester, a group having one or more constituent units of polycarbonate, and a group derived from glycerin monoallyl ether.

[0027] In the above formula (1u), at least one R ｕ R has an alkylene glycol skeleton in which the number of repeating alkylene units having 2 to 6 carbon atoms is 1 or more. ｕ If multiple elements are present in a single molecule, their structures may be identical to each other, or at least one of them may be different from the others.

[0028] R ｕ The lower limit of the number of repeating alkylene units contained in the alkylene glycol skeleton is 1. A high viscosity liquid compound can be obtained when the number of repeating units is 1 or more. The preferred lower limit of the number of repeating units is 2.

[0029] R ｕ The preferred upper limit for the number of repeating alkylene units contained in the alkylene glycol skeleton is 50. A high viscosity liquid compound can be obtained when the number of repeating units is 50 or less. A more preferred upper limit for the number of repeating units is 10.

[0030] R ｕ The number of carbon atoms in the alkylene unit contained in the alkylene glycol skeleton is preferably 3 or 4. Having 3 or 4 carbon atoms in the alkylene unit allows for obtaining a compound that is liquid at room temperature.

[0031] R ｕ Examples of the alkylene glycol skeletons possessed by the above-mentioned material include ethylene glycol, propylene glycol, tetramethylene glycol, and hexamethylene glycol.

[0032] at least one R ｕR represents an organic group having a hydrogen-bonding polar functional group. ｕ By representing an organic group having a hydrogen-bonding polar functional group, phase separation due to aggregation of the urethane skeleton can be effectively suppressed, and transparency can be maintained even after curing. In other words, a cured product with excellent transparency can be obtained. The organic group having a hydrogen-bonding polar functional group is the R having the alkylene glycol skeleton mentioned above. ｕ It may be bonded to the side chain, and R may not have the alkylene glycol skeleton. ｕ It may be bonded to the side chain. The above-mentioned organic group R having a hydrogen-bonding polar functional group ｕ If multiple elements are present in a single molecule, their structures may be identical to each other, or at least one of them may be different from the others.

[0033] R is an organic group having a hydrogen-bonding polar functional group. ｕ These are carbonate groups (*-O-C(=O)-O-*), carboxyl groups (*-C(=O)-OH), carbonyl groups (*-C(=O)-*), nitrile groups (*-C≡N), and amino groups (*-NH ２ , *-NH-*, N(-*) ２ It is preferable that the organic group has at least one group selected from the group consisting of ) (where * represents a bond). R is an organic group having a hydrogen bonding polar functional group. ｕ It is more preferable that R is an organic group having at least one group selected from the group consisting of carbonate groups and carboxyl groups. ｕ However, by having an organic group having at least one group selected from the group consisting of carbonate groups and carboxyl groups, the formation of a phase separation structure during resin curing is suppressed, and a transparent cured product can be obtained.

[0034] The preferred lower limit for the number of carbon atoms in an organic group having a hydrogen-bonding polar functional group is 5. Having 5 or more carbon atoms in the organic group having a hydrogen-bonding polar functional group suppresses the formation of phase separation structures during resin curing, allowing for the production of a transparent cured product. A more preferred lower limit for the number of carbon atoms in the above organic group is 6.

[0035] The preferred upper limit for the number of carbon atoms in an organic group having a hydrogen-bonding polar functional group is 100. By having 100 or fewer carbon atoms in the organic group having a hydrogen-bonding polar functional group, the formation of a phase separation structure during resin curing is suppressed, and a transparent cured product can be obtained. The more preferred upper limit for the number of carbon atoms in the above organic group is 50.

[0036] R ｕ Examples of organic groups having hydrogen-bonding polar functional groups represented by this include ester groups, carboxyl groups, carbonate groups, and amide groups.

[0037] R contained in one molecule of the polymerizable compound represented by the above formula (1u) ｕ R is an organic group having a hydrogen-bonding polar functional group relative to the total number of R groups. ｕ The preferred lower limit for the number of polar functional groups (hereinafter also simply referred to as the content ratio of polar functional groups) is 0.1 mol%. By having a content ratio of 0.1 mol% or more of the above polar functional groups, it is possible to improve the bending resistance of the cured product of the polymerizable compound. A more preferred lower limit for the content ratio of the above polar functional groups is 0.5 mol%, and an even more preferred lower limit is 0.7 mol%.

[0038] A preferred upper limit for the content of the above polar functional groups is 90 mol%. By having a content of 90 mol% or less of the above polar functional groups, it is possible to suppress excessive aggregation of the polymerizable compound, and a cured product with excellent transparency can be obtained. A more preferred upper limit for the content of the above polar functional groups is 80 mol%, and an even more preferred upper limit is 75 mol%.

[0039] When the above-mentioned hydrogen-bonding polar functional group is a carbonate group, the preferred lower limit of the content of the polar functional group is 20 mol%. When the above-mentioned hydrogen-bonding polar functional group is a carbonate group, a content of 20 mol% or more of the polar functional group can further improve the bending resistance of the cured product of the polymerizable compound. When the above-mentioned hydrogen-bonding polar functional group is a carbonate group, a more preferred lower limit of the content of the polar functional group is 25 mol%, and an even more preferred lower limit is 30 mol%.

[0040] When the above-mentioned hydrogen-bonding polar functional group is a carbonate group, the preferred upper limit of the content of the above-mentioned polar functional group is 80 mol%. When the above-mentioned hydrogen-bonding polar functional group is a carbonate group, a cured product with better transparency can be obtained if the content of the above-mentioned polar functional group is 80 mol% or less. When the above-mentioned hydrogen-bonding polar functional group is a carbonate group, a more preferred upper limit of the content of the above-mentioned polar functional group is 75 mol%, and an even more preferred upper limit is 70 mol%.

[0041] When the above-mentioned hydrogen-bonding polar functional group is a carboxyl group, the preferred lower limit of the content of the polar functional group is 0.1 mol%. When the above-mentioned hydrogen-bonding polar functional group is a carboxyl group, a content of 0.1 mol% or more of the polar functional group can further improve the bending resistance of the cured product of the polymerizable compound. When the above-mentioned hydrogen-bonding polar functional group is a carboxyl group, a more preferred lower limit of the content of the polar functional group is 0.5 mol%, and an even more preferred lower limit is 1 mol%.

[0042] When the above-mentioned hydrogen-bonding polar functional group is a carboxyl group, the preferred upper limit of the content of the above-mentioned polar functional group is 20 mol%. When the above-mentioned hydrogen-bonding polar functional group is a carboxyl group, a cured product with better transparency can be obtained if the content of the above-mentioned polar functional group is 20 mol% or less. When the above-mentioned hydrogen-bonding polar functional group is a carboxyl group, a more preferred upper limit of the content of the above-mentioned polar functional group is 15 mol%, and an even more preferred upper limit is 10 mol%.

[0043] In the above formula (1u), at least one R ｕ It is preferable that it has a structure represented by the following formula (2u): at least one R ｕ The structure represented by the following formula (2u) suppresses the formation of sea-island structures during the curing of the curable resin, making it possible to obtain a cured product with excellent transparency.

[0044]

[0045] In equation (2u), * represents a bond.

[0046] In the above formula (1u), at least one R ｕIt is preferable that it has a structure represented by the following formula (3u): at least one R ｕ The structure represented by the following formula (3u) suppresses the formation of sea-island structures during the curing of the curable resin, making it possible to obtain a cured product with excellent transparency.

[0047]

[0048] In equation (3u), * represents a bond, and k ｕ represents 1 or 2, m ｕ represents 0, 1, or 2, and n ｕ represents 0, 1, or 2, m ｕ and n ｕ Neither of these can be zero. This allows for excellent transparency and flexibility.

[0049] In formula (1u), R １ｕ and R ２ｕ Each of these independently represents an organic group having 2 to 10 carbon atoms. By having a lower limit of 2 carbon atoms in the organic group, a high cohesive force derived from the urethane skeleton of the main chain can be expressed. A preferred lower limit for the number of carbon atoms in the organic group is 3, and a more preferred lower limit is 5. Furthermore, by having an upper limit of 10 carbon atoms in the organic group, phase separation can be suppressed, and a transparent liquid state can be maintained. A preferred upper limit for the number of carbon atoms in the organic group is 9, and a more preferred upper limit is 8.

[0050] R １ｕ and R ２ｕ The above-mentioned organic group having 2 to 10 carbon atoms, represented by the above, preferably contains an alkylene group. Examples include a group having one or more constituent units of polyether, a group having one or more constituent units of polypropylene, a group having one or more constituent units of polytetramethylene ether, a group having one or more constituent units of polyester, a group having one or more constituent units of polycarbonate, and a group derived from glycerin monoallyl ether.

[0051] R １ｕ The formula is as follows (R １ｕ -1) or (R １ｕ -2) is preferable.

[0052]

[0053] R ２ｕ The formula is as follows (R ２ｕ -1) or (R ２ｕ -2) is preferable.

[0054]

[0055] Formula (R １ｕ -1), (R １ｕ -2), (R ２ｕ -1) and (R ２ｕ -2) In this case, * represents a bonding hand, b ｕ This represents an integer between 1 and 140.

[0056] Formula (R １ｕ -1), (R １ｕ -2), (R ２ｕ -1) and (R ２ｕ -2) Medium, b ｕ The preferred upper limit is 30. ｕ By having a value less than or equal to 30, a flexible cured product with sufficient crosslinking density can be obtained. ｕ A more preferable upper limit is 10, and an even more preferable upper limit is 5.

[0057] X ｕ represents an organic group. The above organic group is preferably an organic group having 6 to 20 carbon atoms, and more preferably an organic group having 6 to 14 carbon atoms. Furthermore, it is even more preferable that the organic group has an aromatic or aliphatic skeleton within the above preferred range of carbon atoms. ｕPreferably, the diisocyanate is an organic group derived from a diisocyanate skeleton. Examples of the above diisocyanates include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, xylene-1,4-diisocyanate, xylene-1,3-diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenyl ether diisocyanate, 2-nitrodiphenyl-4,4'-diisocyanate, 2,2'-diphenylpropane-4,4'-diisocyanate, 3,3'-dimethyldiphenylmethane-4,4'-diisocyanate, and 4,4'-diphenylpropane diisocyanate. Examples include aromatic diisocyanates such as annetes, m-phenylenediisocyanate, p-phenylenediisocyanate, naphthylene-1,4-diisocyanate, naphthylene-1,5-diisocyanate, and 3,3'-dimethoxydiphenyl-4,4'-diisocyanate; aliphatic diisocyanates such as tetramethylene diisocyanate, hexamethylene diisocyanate, and lysine diisocyanate; and alicyclic diisocyanates such as isophorone diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated xylene diisocyanate, and hydrogenated diphenylmethane diisocyanate. ｕ The structures may be identical to each other, or at least one of them may be different from the others.

[0058] The polymerizable compound represented by formula (1u) above can be synthesized, for example, by the following method: A polyol and a polyisocyanate are heated at 80°C for 3 hours, and after the temperature rise stabilizes, the reaction is carried out at 100°C to obtain a urethane prepolymer. Then, the temperature is raised to 80°C, a basic catalyst is added, and a monoallylated polyether is added, and the mixture is stirred and reacted for 3 hours to obtain the polymerizable compound represented by formula (1u) above. IR measurement revealed approximately 2260 cm⁻¹, which originates from the isocyanate group. －１The reaction endpoint is determined by the disappearance of the peak. As monoallylated polyethers, for example, allyl glycol manufactured by Nippon Emulsifier Co., Ltd., and Uniox PKA-5001, Uniox PKA-5002, Uniox PKA-5003, Uniox PKA-5004, Uniox PKA-5005, Uniox PKA-5011, Uniox PKA-5013, Uniox PKA-5014TF, Uniox PKA-5015, Uniox PKA-5016, and Uniox PKA-5017 manufactured by NOF Corporation can be used.

[0059] The curable resin composition of this disclosure contains a polymerizable compound represented by the above formula (1u). The polymerizable compound represented by the above formula (1u) may be used alone or in combination of two or more types. As described above, the polymerizable compound of this disclosure has excellent bending resistance and transparency of the cured product, and therefore the curable resin composition of this disclosure also has excellent bending resistance and transparency of the cured product. Furthermore, as described above, the polymerizable compound of this disclosure can increase the viscosity and reactivity of the polymerizable compound. Therefore, the curable resin composition of this disclosure can also increase the viscosity and reactivity of the curable resin composition.

[0060] The preferred lower limit for the content of the polymerizable compound represented by formula (1u) in the above curable resin composition is 10% by mass, and the preferred upper limit is 80% by mass. By having the content of the polymerizable compound represented by formula (1u) within this range, a cured product with high flexibility and low surface tack can be obtained. The more preferred lower limit for the content of the polymerizable compound represented by formula (1u) is 20% by mass, and the more preferred upper limit is 70% by mass.

[0061] Preferably, the above curable resin composition further contains a polythiol compound having multiple thiol groups in one molecule and a polymerization initiator. By including a polythiol compound having multiple thiol groups in one molecule and a polymerization initiator in addition to the polymerizable compound represented by formula (1u), hydrogen bonds are formed between the hydrogen-bonding polar functional groups of the polymerizable compound represented by formula (1u) and the thiol groups of the polythiol compound, thereby increasing the compatibility of the polymerizable compound. As a result, it is possible to suppress phase separation due to aggregation of polymerizable compounds that create a sea-island structure in the cured product of the curable resin composition, and thus obtain a cured product with superior transparency.

[0062] Furthermore, when the curable resin composition of this disclosure is used as a encapsulant for a display element, for example, if the curable resin composition in the form of a coating is cured with one side of the coating exposed to air, surface reactivity (surface curability) under atmospheric conditions becomes important. Also, if tack remains on the surface, it poses a risk of foreign matter adhesion, so it is necessary to reduce surface tackiness.

[0063] By including a polymerizable compound represented by formula (1u), a polythiol compound having multiple thiol groups in one molecule, and a polymerization initiator in addition to the polymerizable compound represented by formula (1u), the surface reactivity of the curable resin composition under atmospheric conditions can be enhanced. As a result, the surface tackiness of the cured product of the curable resin composition of this disclosure can be reduced.

[0064] The above-mentioned polythiol compound is a compound having multiple thiol groups in one molecule. Preferably, the thiol groups of the above-mentioned polythiol compound are secondary thiol groups. The fact that the thiol groups of the above-mentioned polythiol compound are secondary thiol groups results in a curable resin composition having excellent storage stability.

[0065] From the viewpoint of reactivity and flexibility, the above polythiol compound preferably has two to four thiol groups per molecule, and more preferably has two to three thiol groups.

[0066] Examples of the polythiol compounds having two thiol groups in one molecule include 1,4-bis(3-mercaptobutyryloxy)butane, trimethylolpropanedipropanthol, butanediol bisthiopropionate, ethylenebis(3-mercaptopropionate), 1,2-bis(2-mercaptoethoxy)ethane, and ethylenebis(thioglycolate). These polythiol compounds having two thiol groups in one molecule may be used individually or in combination of two or more.

[0067] Examples of the polythiol compounds having three or more thiol groups in one molecule include pentaerythritol trippropanthol, 1,3,5-tris(2-(3-sulfanylbutanoyloxy)ethyl)-1,3,5-triazinane-2,4,6-trione, pentaerythritol tetrakis(3-mercaptobutyrate), pentaerythritol tetrakis(3-mercaptopropionate), and dipentaerythritol hexakis(3-mercaptopropionate). These polythiol compounds having three or more thiol groups in one molecule may be used individually or in combination of two or more.

[0068] The preferred lower limit for the content of the polythiol compound in the above curable resin composition is 10% by mass, and the preferred upper limit is 60% by mass. By having the content of the polythiol compound within this range, a cured product with excellent flexibility can be obtained. The more preferred lower limit for the content of the polythiol compound is 15% by mass, and the more preferred upper limit is 50% by mass.

[0069] Examples of polymerization initiators include photopolymerization initiators and thermal polymerization initiators, with photopolymerization initiators being preferred.

[0070] Examples of the above-mentioned photopolymerization initiators include benzophenone compounds, acetophenone compounds, acylphosphine oxide compounds, titanocene compounds, oxime ester compounds, benzoin ether compounds, and thioxanthone compounds. Examples of the above-mentioned photopolymerization initiators include, specifically, 1-hydroxycyclohexylphenyl ketone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone, 2-(dimethylamino)-2-((4-methylphenyl)methyl)-1-(4-(4-morpholinyl)phenyl)-1-butanone, 2,2-dimethoxy-1,2-diphenylethane-1-one, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one, 1-(4-(2-hydroxyethoxy)-phenyl)-2-hydroxy-2-methyl-1-propan-1-one, 1-(4-(phenylthio)phenyl)-1,2-octanedione 2-(O-benzoyloxime), and 2,4,6-trimethylbenzoyldiphenylphosphine oxide (TPO). The above photopolymerization initiators may be used alone or in combination of two or more.

[0071] Examples of the thermal polymerization initiators include those composed of azo compounds and organic peroxides. Examples of the azo compounds include those having a structure in which multiple units such as polyalkylene oxide or polydimethylsiloxane are bonded via an azo group. As for polymer azo compounds having a structure in which multiple units such as polyalkylene oxide are bonded via an azo group, those having a polyethylene oxide structure are preferred. Specific examples of the azo compounds include polycondensates of 4,4'-azobis(4-cyanopentanoic acid) and polyalkylene glycol, and polycondensates of 4,4'-azobis(4-cyanopentanoic acid) and polydimethylsiloxane having terminal amino groups. Examples of the organic peroxides include ketone peroxides, peroxyketals, hydroperoxides, dialkyl peroxides, peroxyesters, diacyl peroxides, and peroxydicarbonates.

[0072] The preferred lower limit for the content of the polymerization initiator in the above curable resin composition is 0.1% by mass, and the preferred upper limit is 5% by mass. Having the polymerization initiator content within this range allows for excellent UV curability. A more preferred lower limit for the content of the polymerization initiator is 0.5% by mass, and a more preferred upper limit is 2% by mass.

[0073] The curable resin composition of this disclosure preferably further contains a polymerizable compound (hereinafter simply referred to as "other polymerizable compound") that does not have the structure represented by formula (1u) above and has two or more polymerizable unsaturated double bonds (also referred to as "aliphatic carbon-carbon double bonds") in one molecule. By containing other polymerizable compounds in the curable resin composition, the viscosity and reactivity of the curable resin composition can be increased.

[0074] The other polymerizable compounds mentioned above are preferably monomers, and examples include diallyl isophthalate, diallyl phthalate, diallyl maleate, diallyl diphenate, triallyl isocyanurate, pentaerythritol tetraallyl ether, and 1,3,4,6-tetraallyltetrahydroimidazo[4,5-d]imidazole-2,5(1H,3H)-dione.

[0075] The other polymerizable compounds mentioned above are preferably (meth)allyl monomers having two or three polymerizable unsaturated double bonds in one molecule. The other polymerizable compounds may be used individually or in combination of two or more.

[0076] The preferred lower limit and preferred upper limit of the content of the other polymerizable compounds in the curable resin composition of this disclosure is 5% by mass. By having the content of the other polymerizable compounds within this range, the viscosity and reactivity of the resulting curable resin composition can be further increased. A more preferred lower limit and a more preferred upper limit of 40% by mass are for the content of the other polymerizable compounds.

[0077] In the curable resin composition of this disclosure, the preferred lower limit of the content of (meth)allyl monomer having two or three polymerizable unsaturated double bonds in one molecule is 5% by mass, and the preferred upper limit is 45% by mass. By having the content of (meth)allyl monomer having two or three polymerizable unsaturated double bonds in one molecule within this range, the viscosity and reactivity of the resulting curable resin composition can be further increased. A more preferred lower limit of the content of (meth)allyl monomer having two or three polymerizable unsaturated double bonds in one molecule is 10% by mass, and a more preferred upper limit is 40% by mass.

[0078] The curable resin composition of this disclosure may contain an antifoaming agent from the viewpoint of improving coatability, etc. Examples of the antifoaming agent include silicone-based antifoaming agents, acrylic polymer-based antifoaming agents, vinyl ether polymer-based antifoaming agents, olefin polymer-based antifoaming agents, and the like.

[0079] The curable resin compositions of this disclosure may further contain various known additives, such as plasticizers, silane coupling agents, sensitizers, thermosetting agents, curing retarders, antioxidants, storage stabilizers, and dispersants, to the extent that they do not impede the objectives of the present invention.

[0080] From the viewpoint of preventing a decrease in curability (reactivity), the curable resin composition of this disclosure preferably contains substantially no solvent, and more specifically, the solvent content in the curable resin composition is preferably 1.5% by mass or less. More preferably, the curable resin composition of this disclosure contains no solvent, and more specifically, the solvent content in the curable resin composition is 0% by mass. That is, the viscosity of the curable resin composition of this disclosure is preferably adjusted not by the solvent, but by the type and physical properties of the polymerizable compound represented by formula (1u) used.

[0081] A method for preparing the curable resin composition of this disclosure includes, for example, a method of mixing the polymerizable compound represented by the above formula (1u) with additives to be added as needed using a mixer (stirrer). Examples of such mixers include homodispersers, homomixers, universal mixers, planetary mixers, kneaders, and three-roll mixers.

[0082] The curable resin composition of this disclosure is preferably curable by at least one of light irradiation and / or heating, and more preferably curable by light irradiation.

[0083] A method for curing the curable resin composition of this disclosure by light irradiation includes, for example, a wavelength of 315 nm to 480 nm and an illuminance of 10 mW / cm². ２ More than 1000mW / cm ２ Examples of methods include irradiating with the following light for more than 10 seconds but less than 10 minutes.

[0084] Examples of light sources for irradiating the curable resin composition of this disclosure include low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, excimer lasers, chemical lamps, black light lamps, microwave-excited mercury lamps, metal halide lamps, sodium lamps, halogen lamps, xenon lamps, LED lamps, fluorescent lamps, sunlight, electron beam irradiation devices, and the like. These light sources may be used individually or in combination of two or more types.

[0085] Examples of methods for irradiating the curable resin composition with light according to this disclosure include simultaneous irradiation with various light sources, sequential irradiation with time differences, and combined irradiation of simultaneous and sequential irradiation, and any of these irradiation methods may be used.

[0086] The curable resin composition of this disclosure can prevent the occurrence of liquid crystal contamination when used in liquid crystal display elements and damage to the organic light-emitting material layer when used in organic EL display elements. A encapsulant for display elements made from the curable resin composition of this disclosure is also one of the present inventions.

[0087] The sealing agent for display elements disclosed herein can be used as a sealing agent for sealing the entire surface, front, rear surface, or periphery of a display element, or as a sealing agent for sealing an opening provided in a display element, and is particularly suitable for sealing the entire surface of a display element. In this specification, "entire surface" does not necessarily mean 100% of the surface of the display element, but rather means the entire required sealing surface of the display element. Furthermore, "front surface" means the side from which light rays are extracted, i.e., the viewing side.

[0088] The encapsulant for display elements of the present disclosure can be used, for example, in organic EL curable resin compositions, sealing agents for liquid crystal display elements, encapsulants for electrochromic substrates, encapsulants for electronic paper, and the like.

[0089] When the curable resin composition of the present disclosure is used as an encapsulant for display elements, the preferable lower limit of the viscosity at 25°C of the curable resin composition of the present disclosure measured with an E-type viscometer at 10 rpm is 100 mPa·s. When the viscosity of the curable resin composition at 25°C is 100 mPa·s or higher, it becomes possible to dispense the curable resin composition with high accuracy. The more preferable lower limit of the viscosity at 25°C of the curable resin composition of the present disclosure is 200 mPa·s.

[0090] The preferable upper limit of the viscosity at 25°C of the curable resin composition of the present disclosure is 60000 mPa·s. When the viscosity of the curable resin composition at 25°C is 60000 mPa·s or lower, it becomes possible to dispense the curable resin composition with high accuracy. The more preferable upper limit of the viscosity at 25°C of the curable resin composition of the present disclosure is 50000 mPa·s.

[0091] Note that the viscosity of the curable resin composition at 25°C can be measured using an E-type viscometer (for example, "VISCOMETER TV-22" manufactured by Toki Sangyo Co., Ltd.) with a No. 4 cone plate under the conditions of 25°C and 10 rpm.

[0092] The viscosity of the curable resin composition at 25°C can be adjusted by changing the type and content of the polymerizable compound represented by formula (1u), the type and content of polymerizable compounds other than formula (1u), the type of polythiol compound, thickeners, fillers, and the like.

[0093] The above curable resin composition is applied onto a substrate to a thickness of 500 µm, and irradiated with light at a wavelength of 365 nm and an illuminance of 100 mW / cm ２The preferred upper limit of the storage modulus at -20°C for the cured product obtained by irradiating it with light for 30 seconds is 500 MPa. Because the storage modulus at -20°C of the cured product is 500 MPa or less, the cured product has high bending resistance (flexibility) even when used in cold regions, making it suitable for use as a peripheral sealant for the casing of foldable smartphones and the like. A more preferred upper limit of the storage modulus at -20°C for the cured product is 300 MPa.

[0094] A preferred lower limit for the storage modulus of the cured product at -20°C is 0.1 MPa. A storage modulus of 0.1 MPa or higher at -20°C ensures the strength required for applications such as sealing agents for display elements. A more preferred lower limit for the storage modulus of the cured product at -20°C is 0.5 MPa.

[0095] The storage modulus of the cured product at -20°C can be measured by the following method. First, the curable resin composition is applied to a release PET film used as a base material. A 500 μm thick silicone rubber sheet is used to create a hole punched out in a shape of 5 mm wide and 45 mm long, so that the resin has a thickness of 500 μm. The top surface is then sealed with another release PET film and flattened by squeezing. After that, a light irradiation device is used to irradiate the surface at a wavelength of 365 nm and an irradiance of 100 mW / cm². ２ The curable resin composition is cured by irradiating it with light from the front side for 30 seconds, obtaining a cured product sandwiched between a pair of release PET films. If the curable resin composition contains a coloring agent, light is also irradiated from the back side at a wavelength of 365 nm and an illuminance of 100 mW / cm². ２ A cured product is obtained by irradiating it with light for 30 seconds. The two release PET films that sandwich the cured product are peeled off, and the dynamic viscoelastic spectrum of the obtained test piece is measured from -40 to 140°C using a viscoelastic spectrometer (e.g., DVA-200, manufactured by IT Measurement Control Co., Ltd.) under the conditions of constant-speed heating tensile mode at 10°C / min, strain of 0.1%, and frequency of 10 Hz. The storage modulus at -20°C obtained as a result is taken as the storage modulus at -20°C of the cured product.

[0096] The storage modulus of the cured product at -20°C can be adjusted by changing the type and content of polymerizable compounds represented by formula (1u), the type and content of polymerizable compounds other than those represented by formula (1u), the type of polythiol compound, fillers, etc.

[0097] The above curable resin composition is applied to a substrate to a thickness of 500 μm, and the illuminance is set to a wavelength of 365 nm and an illuminance of 100 mW / cm². ２ The preferred lower limit of the tensile elongation at 25°C for the cured product obtained by irradiating it with light for 30 seconds is 80%. Because the tensile elongation at 25°C of the cured product is 80% or higher, it has high bending resistance (flexibility), making it suitable for use as a peripheral sealant for the casings of foldable smartphones and the like. A more preferred lower limit for the tensile elongation at 25°C of the cured product is 90%. There is no particular preferred upper limit for the tensile elongation at 25°C of the above cured product, but the practical upper limit is 1000%.

[0098] The tensile elongation at 25°C of the cured material can be measured by the following method. First, the curable resin composition is applied to a release PET film used as a base material. A 500 μm thick silicone rubber sheet is used to create a hole punched out in a shape of 5 mm wide and 45 mm long, and the resin is applied to the recessed portion. The top surface is then sealed with another release PET film and flattened by squeegees. After that, a light irradiation device is used to measure the elongation at a wavelength of 365 nm and an illuminance of 100 mW / cm². ２ The curable resin composition is cured by irradiating it with light from the front side for 30 seconds, obtaining a cured product sandwiched between a pair of release PET films. If the curable resin composition contains a coloring agent, light is also irradiated from the back side at a wavelength of 365 nm and an illuminance of 100 mW / cm². ２ The material is irradiated with light for 30 seconds to obtain a cured product. The two release PET films holding the cured product are peeled off, and the resulting test piece is measured using a tensile testing machine (for example, Shimadzu Corporation's "Autograph AG-XPlus") under the conditions of 25°C, a grip distance of 25 mm, and a tensile speed of 10 mm / min. The resulting tensile elongation at 25°C is taken as the tensile elongation at 25°C for the cured product.

[0099] The tensile elongation at break of the cured product at 25°C can be adjusted by changing the type and content of the polymerizable compound represented by formula (1u), the type and content of polymerizable compounds other than formula (1u), the type of polythiol compound, the filler, and the like.

[0100] A rubber sheet with a thickness of 500 μm is provided with a through hole having a diameter of 5 mm, one side of the hole is sealed with tape, the hole is filled with the curable resin composition described above, and the composition is irradiated with light having a wavelength of 365 nm and an illuminance of 100 mW / cm ２ for 30 seconds to obtain a cured product (hereinafter, also simply referred to as "cured product formed using a 500 μm-thick rubber sheet"). The preferable lower limit of the thickness of the cured product is 200 μm. When the thickness of the cured product formed using the 500 μm-thick rubber sheet is 200 μm or more, the curable resin composition can form a cured product excellent in deep-section curability. A more preferable lower limit of the thickness of the cured product formed using the 500 μm-thick rubber sheet is 400 μm. The upper limit of the thickness of the cured product formed using the 500 μm-thick rubber sheet is 500 μm.

[0101] The thickness of the cured product formed using a 500 μm-thick rubber sheet can be measured by the following method. A rubber sheet with a thickness of 500 μm is provided with a through hole having a diameter of 5 mm, one side of the hole is sealed with tape, and the hole is filled with each curable resin composition. Thereafter, using a light irradiation device, the composition is irradiated with light having a wavelength of 365 nm and an illuminance of 100 mW / cm ２ for 30 seconds to cure the curable resin composition and obtain a cured product. The cured product is taken out, and the thickness of the cured product is measured with a micrometer (for example, "Soft Touch Micro CLM" manufactured by Mitutoyo Corporation). The thickness obtained as a result is taken as the thickness of the cured product formed using the 500 μm-thick rubber sheet.

[0102] The thickness (deep-section curability) of the cured product formed using the 500 μm-thick rubber sheet can be adjusted by changing the type and content of the polymerizable compound represented by formula (1u), the type and content of polymerizable compounds other than formula (1u), the type of polythiol compound, the filler, and the like.

[0103] The above curable resin composition is applied to a substrate to a thickness of 50 μm, and the illuminance is set to a wavelength of 365 nm and an illuminance of 100 mW / cm². ２ The preferred upper limit of the haze value of the cured product obtained by irradiating it with light for 30 seconds is 5%. A cured product with excellent transparency can be obtained when the haze value of the cured product is 5% or less. A more preferred upper limit of the haze value of the cured product is 2%. A haze value of 0% is preferable.

[0104] The haze value of the cured product can be measured by the following method. First, the curable resin composition is applied to a glass substrate (AGC Fabretech Eagle XG) to a thickness of 50 μm, using a 50 μm thick Kapton tape as a dam. Then, the top surface is sealed with glass, and a light irradiation device is used to irradiate it at a wavelength of 365 nm and an irradiance of 100 mW / cm². ２ By irradiating the curable resin composition with light for 30 seconds, a laminate of cured material is obtained. The haze value of the test piece is measured using a colorimeter (for example, "SH7000" manufactured by Nippon Denshoku Industries, Ltd.). The resulting haze value is taken as the haze value of the cured material.

[0105] The haze value of the cured product can be adjusted by changing the type and content of polymerizable compounds represented by formula (1u), the type and content of polymerizable compounds other than those represented by formula (1u), the type of polythiol compound, fillers, etc.

[0106] According to the present invention, it is possible to provide a polymerizable compound that has high viscosity and excellent transparency of the cured product, a curable resin composition containing the polymerizable compound, and a encapsulant for display elements made from the curable resin composition.

[0107] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0108] (Synthesis Example 1: Synthesis of Urethane Allyl Au) 14.19 parts by mass of polytrimethylene ether glycol (SK Chemicals "ECOTRION H-2000", hydroxyl value 56.0 mg KOH / g) as a polyol and 6.08 parts by mass of polycarbonate diol (Mitsubishi Chemical Corporation "BENEBIOL NT-2002", hydroxyl value 56.0 mg KOH / g) as a polyol were placed in a 500 mL separable flask. 3.73 parts by mass of diphenylmethane diisocyanate (Nisso Shoji Co., Ltd. "Pure MDI") as a polyisocyanate were added, and the mixture was stirred at 80°C for 3 hours to allow the reaction to proceed. After the temperature stabilized, the reaction was continued at 100°C to obtain a urethane prepolymer. Subsequently, the temperature was lowered to 80°C, and 0.24 parts by mass of U-CAT 660M (manufactured by Sunapro Co., Ltd.) and 0.98 parts by mass of allyl glycol (manufactured by Nippon Emulsifier Co., Ltd.) were added. The mixture was stirred and reacted for 3 hours to obtain urethane allyl Au with allylated ends.

[0109] Based on the types and amounts of reagents used in the synthesis of urethane allyl At, urethane allyl Au has a structure represented by the following formula (1u-1), and a ｕ is a non-negative integer, and the total R contained in one molecule of urethane allyl Au is 0 or greater. ｕ Of which 30 mol% of R ｕ The structure is represented by the above formula (3u), and the remaining R ｕ The material had the structure represented by the above formula (4u). The content of polar functional groups (carbonate groups) of urethane allyl Au was 30 mol%.

[0110]

[0111]

[0112] In equation (4u), q ｕ is an integer greater than or equal to 1, and * represents a combination.

[0113] (Synthesis Examples 2-9: Synthesis of Urethane Allyl Bu, Cu, Du, Eu, Fu, Gu, Hu, and Zu) Urethane allyl Bu, Cu, Du, Eu, Fu, and Zu were synthesized in the same manner as in Synthesis Example 1, except for changes in the ratio of ECOTRION H-2000 and BENEBIOL NT-2002 and changes in the type of diol compound. Urethane allyl Bu, Cu, Du, Eu, Fu, Gu, Hu, and Zu are R ｕ Aside from the difference in the carboxyl group, it had the same structure as urethane allyl Au. For the introduction of the carboxyl group in urethane allyl Du, Eu, Fu, and Hu, 2,2-bis(hydroxymethyl)butyric acid was used as the diol, while for the introduction of the allyl ether group in urethane allyl Gu and Hu, glycerin monoallyl ether was used as the diol.

[0114] Urethane allyl Bu contains the total R in one molecule. ｕ Of which 50 mol% R ｕ The structure is represented by the above formula (3u), and the remaining R ｕ The compound had the structure represented by the above formula (4u). The content of polar functional groups (carbonate groups) of urethane allyl Bu was 50 mol%.

[0115] Urethane allyl Cu contains the total R in one molecule. ｕ Of which 70 mol% of R ｕ The structure is represented by the above formula (3u), and the remaining R ｕ The compound had the structure represented by the above formula (4u). The content of polar functional groups (carbonate groups) of urethane allyl Cu was 70 mol%.

[0116] Urethane allyl Du contains the total R in one molecule. ｕ Of which 1 mol% of R ｕ It has a structure represented by the following formula (5u), and the remaining R ｕ The compound had the structure represented by the above formula (4u). The content of the polar functional group (carboxyl group) of urethane allyl Du was 1 mol%.

[0117]

[0118] In equation (5u), * represents a coupling.

[0119] Urethane allyl Eu contains the total R in one molecule. ｕ Of which 5 mol% of R ｕ It has a structure represented by the following formula (5u), and the remaining R ｕ The compound had the structure represented by the above formula (4u). The content of the polar functional group (carboxyl group) of urethane allyl Eu was 5 mol%.

[0120] Urethane allyl Fu contains the total R in one molecule. ｕ Of which 10 mol% of R ｕ It has a structure represented by the following formula (5u), and the remaining R ｕ The compound had the structure represented by the above formula (4u). The content of polar functional groups (carboxyl groups) of urethane allyl Fu was 10 mol%.

[0121] Urethane allyl Gu contains the total R in one molecule. ｕ Of which 25 mol% of R ｕ The structure is represented by the above formula (3u), and contains 70 mol% R ｕ It has a structure represented by the above formula (4u), and contains 5 mol% R ｕ The compound had a structure represented by the following formula (6u). The content of polar functional groups (carbonate groups) of urethane allyl Gu was 25 mol%. The content of reactive functional groups (allyl ether groups) of urethane allyl Gu was 5 mol%.

[0122]

[0123] In equation (6u), * represents a bond.

[0124] Urethane allyl Hu contains the total R in one molecule. ｕ Of which 90 mol% R ｕ It has a structure represented by the above formula (4u), and contains 5 mol% R ｕ It has a structure represented by the above formula (5u), and contains 5 mol% R ｕ The compound had the structure represented by the above formula (6u). The content of polar functional groups (carboxyl groups) of urethane allyl Hu was 5 mol%. In addition, the content of reactive functional groups (allyl ether groups) of urethane allyl Hu was 5 mol%.

[0125] Urethane allyl Zu contains all R in one molecule of said urethane allyl Zu. ｕ The compound had the structure represented by the above formula (4u).

[0126] (Examples 1-11, Comparative Examples 1-2) Each material was mixed in a planetary agitator (Sinky Co., Ltd., "Awatori Rentaro") according to the mixing ratios (mass ratios) listed in Tables 1-2 to obtain the respective curable resin compositions of the Examples and Comparative Examples. Details of the materials indicated by abbreviations in the table are as follows.

[0127] <Polythiol Compounds> ・Karenz MT BD 1: 1,4-bis(3-mercaptobutyryloxy)butane (manufactured by Resonaq) ・Multiol Y-2: Trimethylolpropanedipropanthol (manufactured by Sakai Chemical Industry Co., Ltd.) ・Multiol Y-3: Pentaerythritoltripropanthol (manufactured by Sakai Chemical Industry Co., Ltd.) <Other Polymerizable Compounds> ・TAIC: Triallyl isocyanurate (manufactured by Shinryo Co., Ltd., an allyl monomer having three polymerizable unsaturated double bonds in one molecule) ・Daiso Dap 100 monomer: Diallyl isophthalate monomer (DAIM, manufactured by Osaka Soda Co., Ltd., an allyl monomer having two polymerizable unsaturated double bonds in one molecule) <Polymerization Initiators> ・Omnirad TPO-N: 2,4,6-trimethylbenzoyldiphenylphosphine oxide (TPO-N, IGM Resins (Manufactured by B.V. Corporation, photopolymerization initiator)

[0128]

[0129]

[0130] (Viscosity of curable resin composition at 25°C) 0.4 mL of the obtained curable resin composition was taken, and its viscosity was measured at 25°C and 10 rpm using an E-type viscometer (Toki Sangyo Co., Ltd., "VISCOMETER TV-22") with a No. 4 cone plate. The viscosity at 25°C was evaluated as follows: "A" if the viscosity was 1000 mPa·s or higher, and "B" if it was less than 1000 mPa·s. The results are shown in Table 3.

[0131] (Storage modulus of cured material at -20°C) The obtained curable resin composition was applied to a release PET film used as a base material. A 500 μm thick silicone rubber sheet was used to create holes in the recessed areas, which were 5 mm wide and 45 mm long, so that the total thickness of the recessed area was 500 μm. The top surface was then sealed with another release PET film and flattened by squeegeeing. Subsequently, a light irradiation device (CCS Corporation, "UVS01-01") was used to irradiate the surface at a wavelength of 365 nm and an irradiance of 100 mW / cm². ２ The curable resin composition was cured by irradiating it with light from the front side for 30 seconds, and a cured product was obtained sandwiched between a pair of release PET films. Both release PET films sandwiching the cured product were peeled off, and the dynamic viscoelastic spectrum of the obtained test piece was measured from -40 to 140°C using a viscoelastic spectrometer (IT Measurement Control Co., Ltd., DVA-200) under constant-speed heating tensile mode conditions of 10°C / min, strain of 0.1%, and frequency of 10 Hz. The storage modulus at -20°C obtained as a result was defined as the storage modulus at -20°C of the cured product. The storage modulus at -20°C was evaluated as follows: "A" if the storage modulus at -20°C was 500 MPa or less, and "B" if it exceeded 500 MPa. The results are shown in Table 3.

[0132] (Tensile elongation at 25°C of cured material) The tensile elongation at 25°C was measured using a tensile testing machine (Shimadzu Corporation, "Autograph AG-XPlus") obtained in the same manner as described above for "(Storage modulus of cured material at -20°C)". The tensile elongation at 25°C was evaluated as follows: "A" if the tensile elongation at 25°C was 80% or more, and "B" if it was less than 80%. The results are shown in Table 3.

[0133] (Haze value of cured product) The curable resin composition was applied to a glass substrate (AGC Fabretech Eagle XG) to a thickness of 50 μm using 50 μm thick Kapton tape as a dam. The top surface was then sealed with glass, and light irradiation was performed using a light irradiation device (CCS Corporation, "UVS01-01") at a wavelength of 365 nm and an irradiance of 100 mW / cm². ２A curable resin composition was cured by irradiating it with light for 30 seconds to obtain a cured product. The haze value of the test piece was measured using a colorimeter (SH7000, manufactured by Nippon Denshoku Industries Co., Ltd.). The haze value was evaluated as "A" if it was 5% or less, and "B" if it was greater than 5%. The results are shown in Table 3.

[0134] (Surface tackiness of cured material) The curable resin composition was applied to a glass substrate (AGC Fabretech Eagle XG) to a thickness of 50 μm using 50 μm thick Kapton tape as a dam. Then, the top surface was squeegeeed with glass, and with the coated surface exposed to air, light irradiation was performed using a light irradiation device (CCS Corporation, "UVS01-01") at a wavelength of 365 nm and an irradiance of 100 mW / cm². ２ The curable resin composition was cured by irradiating it with light for 30 seconds to obtain a cured product. Tackiness was evaluated using Rhesca's "TAC-II" under the following conditions: probe diameter Φ5 mm, indentation speed 120 mm / min, release speed 5 mm / min, indentation pressure 200 gf, and indentation time 5 s. 200 gf / cm ２ If the following conditions are met, it will be classified as "A", 200 gf / cm². ２ Surface tackiness of the cured product was evaluated, with values ​​exceeding a certain threshold designated as "B". The results are shown in Table 3. It should be noted that curable resin compositions with a surface tackiness rating of A have higher reactivity of the polymerizable compounds contained in the composition than curable resin compositions with a rating of B.

[0135] (Deep curing properties of the cured material) A 500 μm thick rubber sheet was prepared with a 5 mm diameter through-hole, and one side was sealed with tape. Each curable resin composition was then filled into the hole. Next, a light irradiation device (CCS Corporation, "UVS01-01") was used to irradiate the material at a wavelength of 365 nm and an irradiance of 100 mW / cm². ２A cured product was obtained by irradiating it with light for 30 seconds. The cured product was then removed, and its thickness was measured using a micrometer (Mitutoyo Corporation, "Soft Touch Micro CLM"). Deep curing properties were evaluated, with "A" indicating a thickness of 200 μm or more, and "B" indicating a thickness of less than 200 μm. The results are shown in Table 3. It should be noted that curable resin compositions with a deep curing property rating of A have higher reactivity of the polymerizable compounds contained in the composition than curable resin compositions with a rating of B.

[0136]

[0137] According to the present invention, it is possible to provide a polymerizable compound that has high viscosity and excellent transparency of the cured product, a curable resin composition containing the polymerizable compound, and a encapsulant for display elements made from the curable resin composition.

Claims

1. A polymerizable compound characterized by being represented by the following formula (1u). In formula (1u), a ｕ represents a non-negative integer, R ｕ Each of these independently represents an organic group having 2 to 10 carbon atoms, and at least one R ｕ It has an alkylene glycol skeleton in which the number of repeating alkylene units having 2 to 6 carbon atoms is 1 or more, and at least one R ｕ R represents an organic group having a hydrogen-bonding polar functional group. １ｕ and R ２ｕ Each of these independently represents an organic group with 2 to 10 carbon atoms, X ｕ represents an organic group.

2. In the above formula (1u), R ｕ The polymerizable compound according to claim 1, wherein the number of carbon atoms in the alkylene unit contained in the alkylene glycol skeleton is 3 or 4.

3. In formula (1u) above, at least one R ｕ is the polymerizable compound according to claim 1, which has a structure represented by the following formula (2u). In formula (2u), * represents a bonding site.

4. In formula (1u), at least one R ｕ The polymerizable compound according to claim 1, having a structure represented by the following formula (3u). In equation (3u), * represents a bond, and k ｕ represents 1 or 2, m ｕ represents 0, 1, or 2, and n ｕ represents 0, 1, or 2, m ｕ and n ｕ Both of these values ​​cannot be zero.

5. A curable resin composition characterized by containing the polymerizable compound described in any one of claims 1 to 4.

6. The curable resin composition according to claim 5, further comprising a polythiol compound having multiple thiol groups in one molecule and a polymerization initiator.

7. The curable resin composition is applied to the substrate to a thickness of 500 μm, and exposed to light at a wavelength of 365 nm and an illuminance of 100 mW / cm². ２ The storage modulus of the cured product obtained by irradiating with light for 30 seconds is 500 MPa or less at -20°C. The curable resin composition is applied to a substrate to a thickness of 50 μm, and the light is applied at a wavelength of 365 nm and an illuminance of 100 mW / cm². ２ The curable resin composition according to claim 5, wherein the haze value of the cured product obtained by irradiating it with light for 30 seconds is 5% or less.

8. A encapsulant for a display element, characterized by comprising the curable resin composition described in claim 5.

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