Curable resin composition and sealant for display device

Abstract

To provide a curable resin composition that has excellent application properties, low dielectric characteristics after curing, and superior heat resistance, and to provide a sealant for display device comprising the curable resin composition.SOLUTION: A curable resin composition contains an aliphatic bismaleimide compound, a monomaleimide compound, a compound having a vinyloxy group, and a polymerization initiator, wherein the content of the compound having a vinyloxy group is 10 pts.mass or more and 30 pts.mass or less based on 100 pts.mass in total of the aliphatic bismaleimide compound, the monomaleimide compound, and the compound having a vinyloxy group, and the composition contains no solvent or contains 0.05 mass% or less of a solvent.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a curable resin composition. The present invention also relates to a sealant for display elements, which is obtained by using the curable resin composition. [Background technology]

[0002] In recent years, the field of electronic devices has seen a demand for faster transmission and reception of larger volumes of data. The practical application of so-called fifth-generation mobile communication systems (5G) is also progressing, and this has led to an increase in the frequency of transmission signals. However, this increase in frequency has led to a problem of increased attenuation of transmission signals (transmission loss). Furthermore, display devices with capacitive touch panels are also becoming thinner and larger. Therefore, curable resin compositions used as interlayer insulating materials for printed wiring boards, sealants for display devices, and the like, require low dielectric properties, such as low dielectric constant and low dielectric loss tangent. For example, Patent Documents 1 to 3 disclose resin compositions containing bismaleimide compounds each having a specific structure, as curable resin compositions with excellent low dielectric properties. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-046517 [Patent Document 2] International Publication No. 2022 / 004211 [Patent Document 3] Japanese Patent Application Publication No. 2017-71738 Summary of the Invention [Problem to be solved by the invention]

[0004] Although conventional curable resin compositions containing bismaleimide compounds have excellent low dielectric loss tangents, there has been a demand for further reduction in the dielectric constant. One possible way to lower the dielectric constant is to reduce the number of crosslinking points to suppress polarization, but reducing the number of crosslinking points poses problems such as a decrease in the glass transition temperature, resulting in a cured product with poor heat resistance.

[0005] The present invention aims to provide a curable resin composition that has excellent coatability, low dielectric properties, and heat resistance after curing. The present invention also relates to a sealant for display elements that uses the curable resin composition. [Means for solving the problem]

[0006] Disclosure 1 relates to a curable resin composition comprising an aliphatic bismaleimide compound, a monomaleimide compound, a compound having a vinyloxy group, and a polymerization initiator, wherein the content of the compound having a vinyloxy group is 10 parts by mass or more and 30 parts by mass or less relative to a total of 100 parts by mass of the aliphatic bismaleimide compound, the monomaleimide compound, and the compound having a vinyloxy group, and the curable resin composition does not contain a solvent or contains 0.05% by mass or less of a solvent. Disclosure 2 is the curable resin composition of Disclosure 1, in which the content of the aliphatic bismaleimide compound is 10 parts by mass or more and 89 parts by mass or less based on 100 parts by mass of the total of the aliphatic bismaleimide compound, the monomaleimide compound, and the compound having a vinyloxy group. Disclosure 3 is the curable resin composition according to Disclosure 1 or 2, wherein the aliphatic bismaleimide compound has a molecular weight of 880 or more and 5,550 or less. Disclosure 4 is the curable resin composition according to Disclosure 1, 2, or 3, wherein the aliphatic bismaleimide compound has 40 or more and 360 or less carbon atoms. Disclosure 5 is a sealant for a display element, which is formed using the curable resin composition of Disclosure 1, 2, 3 or 4. The present invention will be described in detail below.

[0007] The present inventors have investigated the possibility of improving the low dielectric properties and heat resistance of a curable resin composition after curing by using a combination of an aliphatic bismaleimide compound, a monomaleimide compound, and a polymerization initiator. However, the resulting curable resin composition sometimes has high viscosity and poor coatability. Furthermore, using a solvent to reduce the viscosity of the curable resin composition poses problems such as the need for a drying process, deterioration of other materials, and outgassing. As a result of extensive research, the present inventors have found that by further adding a specific amount of a compound having a vinyloxy group to the curable resin composition, a curable resin composition with excellent coatability can be obtained without using a solvent, without deteriorating the low dielectric properties and heat resistance after curing, and have completed the present invention.

[0008] The curable resin composition of the present invention contains an aliphatic bismaleimide compound. By using the aliphatic bismaleimide compound in combination with a monomaleimide compound described below, the curable resin composition of the present invention will have low dielectric properties and excellent heat resistance after curing. In this specification, the term "aliphatic" in the above-mentioned aliphatic bismaleimide compounds and the aliphatic monomaleimide compounds described below means that the structure directly bonded to the maleimide group is an aliphatic hydrocarbon. Furthermore, aliphatic bismaleimide compounds having a vinyloxy group are treated as compounds having a vinyloxy group described below, rather than as the above-mentioned aliphatic bismaleimide compounds.

[0009] The aliphatic bismaleimide compound has a molecular weight of preferably 880 (lower limit) and 5550 (upper limit). When the molecular weight of the aliphatic bismaleimide compound is within this range, the resulting curable resin composition exhibits excellent effects of achieving both low dielectric properties and heat resistance after curing. The aliphatic bismaleimide compound has a molecular weight of more preferably 890 (lower limit) and 4000 (upper limit). In this specification, the "molecular weight" refers to the molecular weight calculated from the structural formula of a compound with a specific molecular structure, but may be expressed as the number average molecular weight for compounds with a wide distribution of polymerization degrees and compounds with unspecified modification sites. The "number average molecular weight" referred to in this specification is a value calculated by measuring the number average molecular weight in terms of polystyrene using gel permeation chromatography (GPC) with tetrahydrofuran as a solvent. Columns used for measuring the number average molecular weight in terms of polystyrene using GPC include, for example, JAIGEL-2H-A (manufactured by Japan Analytical Industry Co., Ltd.).

[0010] The aliphatic bismaleimide compound preferably has a lower limit of 40 carbon atoms and a higher limit of 360 carbon atoms. When the aliphatic bismaleimide compound has a carbon number within this range, the resulting curable resin composition exhibits excellent effects of achieving both low dielectric properties and heat resistance after curing. The aliphatic bismaleimide compound more preferably has a lower limit of 44 carbon atoms and a higher limit of 350 carbon atoms. The number of carbon atoms in the aliphatic bismaleimide compound includes the number of carbon atoms contained in the maleimide group. Furthermore, in this specification, the "carbon number" refers to the carbon number determined from the structural formula for compounds with a specific molecular structure. However, for compounds with a wide distribution of polymerization degrees and compounds with an unspecified modification site, the "carbon number" refers to the carbon number of the compound corresponding to the position of the highest peak observed when determining the molecular weight by GPC using the method described above. When there are multiple peaks with the highest peak height, the carbon number refers to the carbon number corresponding to the positions of all of those peaks. For example, when there are multiple peaks with the highest peak height, if at least one of them has a carbon number equal to or greater than the preferred lower limit, the carbon number of the aliphatic bismaleimide compound is considered to be equal to or greater than the preferred lower limit, and the same applies to the preferred upper limit, the more preferred lower limit, and the more preferred upper limit.

[0011] Examples of the aliphatic bismaleimide compound include a compound represented by the following formula (1), a compound represented by the following formula (2), and a compound represented by the following formula (3). Of these, the compound represented by the following formula (1) and the compound represented by the following formula (2) are preferred. The compound represented by the following formula (1), the compound represented by the following formula (2), and the compound represented by the following formula (3) may all have a hydrogen atom substituted.

[0012] [ka]

[0013] [ka]

[0014] In formula (2), n is 1 or more and 10 or less.

[0015] [ka]

[0016] In formula (3), m is 1 or more and 10 or less.

[0017] The preferred lower limit of the content of the aliphatic bismaleimide compound is 10 parts by mass, and the preferred upper limit is 89 parts by mass, based on 100 parts by mass of the total of the aliphatic bismaleimide compound, the monomaleimide compound described below, and the compound having a vinyloxy group described below. When the content of the aliphatic bismaleimide compound is within this range, the resulting curable resin composition exhibits an excellent effect of achieving both low dielectric properties and heat resistance after curing. The more preferred lower limit of the content of the aliphatic bismaleimide compound is 20 parts by mass, and the more preferred upper limit is 80 parts by mass.

[0018] The curable resin composition of the present invention contains a monomaleimide compound. As described above, by using the monomaleimide compound in combination with the aliphatic bismaleimide compound, the curable resin composition of the present invention exhibits low dielectric properties and excellent heat resistance after curing. The monomaleimide compound having a vinyloxy group will be treated as a compound having a vinyloxy group described below, rather than as the above-mentioned monomaleimide compound.

[0019] The monomaleimide compound has a molecular weight of preferably 139 or less and 270 or less. When the molecular weight of the monomaleimide compound is within this range, the resulting curable resin composition exhibits an excellent effect of achieving both low dielectric properties and heat resistance after curing.

[0020] The monomaleimide compound has a carbon number of preferably 7 as its lower limit and 16 as its upper limit. When the monomaleimide compound has a carbon number within this range, the resulting curable resin composition after curing has an excellent effect of achieving both low dielectric properties and heat resistance. The number of carbon atoms in the monomaleimide compound includes the number of carbon atoms contained in the maleimide group.

[0021] The monomaleimide compound may be an aliphatic monomaleimide compound or an aromatic monomaleimide compound, of which an aliphatic monomaleimide compound is preferred because the resulting curable resin composition will have better low dielectric properties after curing.

[0022] Examples of the aliphatic monomaleimide compound include N-methylmaleimide, N-ethylmaleimide, N-propylmaleimide, N-isopropylmaleimide, N-laurylmaleimide, N-hexylmaleimide, N-vinylmaleimide, N-allylmaleimide, N-(3-butenyl)maleimide, N-(4-pentenyl)maleimide, etc. Among these, N-alkylmaleimides having 7 to 16 carbon atoms are preferred.

[0023] Examples of the aromatic monomaleimide compound include N-phenylmaleimide, N-(1-naphthyl)maleimide, N-(2-naphthyl)maleimide, 1-(2-anthracetyl)-1H-pyrrole-2,5-dione, N-(4-methylphenyl)maleimide, and 1-[4-(1,1'-dimethylethyl)phenyl]-1H-pyrrole-2,5-dione.

[0024] The preferred lower limit of the content of the monomaleimide compound per 100 parts by mass of the total of the aliphatic bismaleimide compound, the monomaleimide compound, and the compound having a vinyloxy group described below is 1 part by mass, and the preferred upper limit is 80 parts by mass. When the content of the monomaleimide compound is within this range, the obtained curable resin composition becomes even more excellent in the effect of achieving both low dielectric properties and heat resistance after curing. The more preferred lower limit of the content of the monomaleimide compound is 10 parts by mass, and the more preferred upper limit is 70 parts by mass.

[0025] The curable resin composition of the present invention contains a compound having a vinyloxy group. By using the compound having a vinyloxy group, the curable resin composition of the present invention can have excellent coatability without deteriorating the low dielectric properties and heat resistance after curing, even without using a solvent.

[0026] The vinyloxy group-containing compound preferably has a molecular weight of 70 (lower limit) and 300 (upper limit). When the molecular weight of the aliphatic monomaleimide compound is within this range, the resulting curable resin composition has excellent coatability. The vinyloxy group-containing compound more preferably has a molecular weight of 100 (lower limit) and 201 (upper limit).

[0027] The compound having a vinyloxy group is preferably a chain aliphatic compound from the viewpoint of further improving the low dielectric properties of the resulting curable resin composition after curing. The vinyloxy group-containing compound is preferably a compound having one vinyloxy group per molecule, from the viewpoint of further improving the heat resistance of the resulting curable resin composition after curing. Furthermore, the compound having a vinyloxy group preferably has a (meth)acryloyl group, from the viewpoint of further improving the heat resistance of the resulting curable resin composition after curing. In this specification, the term "(meth)acryloyl" means acryloyl or methacryloyl.

[0028] Examples of compounds having the vinyloxy group include 1-vinyloxybutane, 2-ethyl-1-(vinyloxy)hexane, diethylene glycol methyl vinyl ether, triethylene glycol methyl vinyl ether, 2-vinyloxyethyl (meth)acrylate, and 2-(2-vinyloxyethoxy)ethyl (meth)acrylate. In this specification, the term "(meth)acrylate" means acrylate or methacrylate.

[0029] The lower limit of the content of the vinyloxy group-containing compound in 100 parts by mass of the total of the aliphatic bismaleimide compound, the monomaleimide compound, and the vinyloxy group-containing compound is 10 parts by mass, and the upper limit is 30 parts by mass. When the content of the vinyloxy group-containing compound is within this range, the curable resin composition of the present invention exhibits excellent coatability without deteriorating the low dielectric properties and heat resistance after curing. The lower limit of the content of the vinyloxy group-containing compound is preferably 15 parts by mass, and the upper limit is preferably 25 parts by mass, and more preferably 17 parts by mass, and more preferably 22 parts by mass.

[0030] The preferred lower limit of the total content of the aliphatic bismaleimide compound, the monomaleimide compound, and the compound having a vinyloxy group per 100 parts by mass of the curable resin composition of the present invention is 20 parts by mass, and the preferred upper limit is 80 parts by mass. When the total content of the aliphatic bismaleimide compound, the monomaleimide compound, and the compound having a vinyloxy group is within this range, the resulting curable resin composition will have better curability and adhesiveness.

[0031] The curable resin composition of the present invention contains a polymerization initiator. Examples of the polymerization initiator include a thermal radical polymerization initiator, a photoradical polymerization initiator, etc. Among these, a photoradical polymerization initiator is preferred.

[0032] Examples of the photoradical polymerization initiator include benzophenone compounds, acetophenone compounds, acylphosphine oxide compounds, titanocene compounds, oxime ester compounds, benzoin ether compounds, and thioxanthone compounds. Specific examples of the photoradical polymerization initiator include 1-hydroxycyclohexyl phenyl 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-diphenylethan-1-one, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, and 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), 2-(acetoxyimino)-1-(4-(4-(2-hydroxyethoxy)phenylthio)phenyl)propan-1-one, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,4-dimethylthioxanthen-9-one, and the like.

[0033] Examples of the thermal radical polymerization initiator include organic peroxides and azo compounds. Examples of the organic peroxides include 1,1-bis(t-hexylperoxy)-3,3,5-trimethylcyclohexane, t-hexylperoxypivalate, t-butylperoxypivalate, 2,5-dimethyl-2,5-bis(2-ethylhexanoylperoxy)hexane, t-hexylperoxy-2-ethylhexanoate, t-butylperoxy-2-ethylhexanoate, t-butylperoxyisobutyrate, t-butylperoxy-3,5,5-trimethylhexanoate, and t-butylperoxylaurate. Examples of the azo compound include 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2-methylbutyronitrile), and 1,1'-azobis(cyclohexane-1-carbonitrile).

[0034] The content of the polymerization initiator is preferably 0.1 parts by mass at the lower limit and 5 parts by mass at the upper limit, relative to 100 parts by mass of the total of the aliphatic bismaleimide compound, the monomaleimide compound, and the compound having a vinyloxy group. By using the polymerization initiator in this range, the resulting curable resin composition has better storage stability and curability. The lower limit of the content of the polymerization initiator is more preferably 0.5 parts by mass, and the upper limit is more preferably 2 parts by mass.

[0035] From the viewpoint of the flatness of the coating film, the curable resin composition of the present invention preferably further contains a leveling agent. Examples of the leveling agent include polyurethane leveling agents, silicone leveling agents, fluorine leveling agents, and acrylic leveling agents.

[0036] The content of the leveling agent is preferably 0.01 parts by mass at the lower limit and 1.0 parts by mass at the upper limit, relative to 100 parts by mass of the total of the aliphatic bismaleimide compound, the monomaleimide compound, and the compound having a vinyloxy group. By using a leveling agent in this range, the resulting curable resin composition exhibits superior coatability and coating film flatness. The lower limit of the content of the leveling agent is more preferably 0.1 parts by mass, and the upper limit is more preferably 0.5 parts by mass.

[0037] The curable resin composition of the present invention may further contain an inorganic filler within a range that does not deteriorate the coatability, etc. By containing the inorganic filler, the obtained curable resin composition will have even more excellent low dielectric properties after curing. Examples of the inorganic filler include silica, alumina, boron nitride, magnesium oxide, boehmite, etc. Among these, silica is preferred.

[0038] The curable resin composition of the present invention may further contain an organic filler for the purposes of stress relaxation, toughness impartation, etc., within a range that does not impair the coating properties, etc. Examples of the organic filler include silicone rubber particles, acrylic rubber particles, urethane rubber particles, polyamide particles, polyamideimide particles, polyimide particles, benzoguanamine particles, and core-shell particles thereof. Among these, polyamide particles, polyamideimide particles, and polyimide particles are preferred.

[0039] The curable resin composition of the present invention may further contain a polymer component within a range that does not deteriorate the coating properties, etc. The polymer component plays a role as a film-forming component.

[0040] The number average molecular weight of the polymer component preferably has a lower limit of 3,000 and an upper limit of 100,000. When the number average molecular weight of the polymer component is within this range, the resulting curable resin composition has better flexibility and processability before curing and better heat resistance after curing. The number average molecular weight of the polymer component is more preferably 5,000 and an upper limit of 80,000.

[0041] Examples of the polymer component include polyimide, phenoxy resin, polyamide, polyamideimide, polymaleimide, cyanate resin, benzoxazine resin, acrylic resin, urethane resin, polyester, etc. Among these, from the viewpoint of heat resistance, polyimide, polyamide, polyamideimide, and polymaleimide are preferred, and polyimide is more preferred.

[0042] The curable resin composition of the present invention may further contain additives such as a heat curing agent, a curing accelerator, a dispersant, a flame retardant, a coupling agent, a storage stabilizer, a bleeding inhibitor, and a fluxing agent.

[0043] The curable resin composition of the present invention does not contain a solvent or contains 0.05 mass% or less of a solvent. By not containing the solvent or, if it contains the solvent, keeping the content of the solvent to 0.05 mass% or less, the curable resin composition of the present invention does not require a drying step after application, and can suppress deterioration of other materials and generation of outgassing.

[0044] Examples of a method for producing the curable resin composition of the present invention include a method of using a mixer to mix the aliphatic bismaleimide compound, the monomaleimide compound, the compound having a vinyloxy group, a polymerization initiator, a leveling agent, etc. Examples of the mixer include a homodisper, a universal mixer, a Banbury mixer, and a kneader.

[0045] The curable resin composition of the present invention preferably has an upper limit of viscosity at 25°C of 300 mPa·s. When the viscosity at 25°C is 300 mPa·s or less, the curable resin composition of the present invention has better coatability. The more preferred upper limit of the viscosity is 100 mPa·s. There is no particular preferred lower limit to the viscosity, but the substantial lower limit is 5 mPa·s. In this specification, the "viscosity" refers to a value measured using an E-type viscometer at 100 rpm. Examples of the E-type viscometer include the VISCOMETER TV-22 (manufactured by Toki Sangyo Co., Ltd.), and a CP1 type cone plate can be used.

[0046] A cured product can be obtained by applying the curable resin composition of the present invention to a substrate film and curing the resulting coating.

[0047] The curable resin composition of the present invention is cured using an LED UV lamp at a wavelength of 365 nm and an illuminance of 100 mW / cm. 2 UV rays of 3000mJ / cm 2 When the composition is cured by irradiating the composition with light or by heating at 190°C for 1 hour, or by both, the reaction rate is preferably 85% or more, as determined from the amount of heat generated by differential scanning calorimetry of the curable resin composition before curing and the cured product of the curable resin composition. A reaction rate of 85% or more makes the curable resin composition of the present invention more suitable for use as an adhesive, a sealant for display elements, an interlayer insulating material, and the like. A preferred lower limit of the reaction rate is 87%. The higher the reaction rate, the better, and 100% is most preferable. The differential scanning calorimetry is performed using a differential scanning calorimeter in a temperature range of 25° C. to 300° C. at a temperature rise rate of 10° C. / min. Examples of the differential scanning calorimeter include DSC200 (manufactured by Hitachi High-Tech Science Corporation).

[0048] The curable resin composition of the present invention preferably has an upper limit of the dielectric constant at 23°C after curing of 2.5. Since the dielectric constant at 23°C after curing is 2.5 or less, the curable resin composition of the present invention can be suitably used as a sealant for use in display elements having touch panels, an interlayer insulating material for multilayer printed wiring boards, etc. The more preferred upper limit of the dielectric constant at 23°C after curing is 2.4. There is no particular preferred lower limit for the dielectric constant after curing, but the substantial lower limit is 2.2. The dielectric constant and the dielectric loss tangent described below are values ​​measured at 1.0 GHz using a dielectric constant measuring device and a network analyzer. The cured product for measuring the dielectric constant and the dielectric loss tangent described below can be obtained by curing a coating film of the curable resin composition having a thickness of 40 to 200 μm. As for the curing method, in the case of a photocurable curable resin composition, the curing is carried out at a wavelength of 365 nm and an illuminance of 100 mW / cm. 2 UV rays of 3000mJ / cm 2 In the case of a thermosetting curable resin composition, a method of heating at 190°C for 1 hour is used, and in the case of a photothermosetting curable resin composition, a combination of these two methods is used.

[0049] The curable resin composition of the present invention preferably has a dielectric loss tangent at 23°C after curing of less than 0.0030. Since the dielectric loss tangent at 23°C after curing is less than 0.0030, the curable resin composition of the present invention can be suitably used as a sealant for use in display elements having touch panels, an interlayer insulating material for multilayer printed wiring boards, etc. It is more preferable that the dielectric loss tangent at 23°C after curing is 0.0025 or less. There is no particular preferred lower limit for the dielectric loss tangent after curing, but the substantial lower limit is 0.0023.

[0050] The curable resin composition of the present invention has a preferable lower limit of the glass transition temperature after curing of 140° C. Since the curable resin composition of the present invention has a glass transition temperature of 140° C. or higher after curing, the curable resin composition of the present invention can be suitably used in applications that particularly require heat resistance. The more preferable lower limit of the glass transition temperature after curing is 150° C. There is no particular upper limit to the glass transition temperature after curing, but the practical upper limit is 200°C. In this specification, the "glass transition temperature" refers to the temperature at which a maximum due to micro-Brownian motion appears among the maximum loss tangents (tan δ) obtained by dynamic viscoelasticity measurement. The glass transition temperature can be measured by a conventionally known method using a dynamic viscoelasticity measuring device or the like. The cured product for measuring the glass transition temperature and the 5% weight loss temperature described below can be obtained by applying the curable resin composition to a substrate PET film to a thickness of 100 μm and then curing it. For a photocurable curable resin composition, the curing method is carried out at a wavelength of 365 nm and an illuminance of 100 mW / cm. 2 UV rays of 3000mJ / cm 2 In the case of a thermosetting curable resin composition, a method of heating at 190°C for 1 hour is used, and in the case of a photothermosetting curable resin composition, a combination of these two methods is used.

[0051] The curable resin composition of the present invention preferably has a 5% weight loss temperature after curing exceeding 390°C. By having a 5% weight loss temperature after curing exceeding 390°C, the curable resin composition of the present invention can be suitably used in applications that particularly require heat resistance. It is more preferable that the 5% weight loss temperature after curing of the curable resin composition of the present invention exceeds 400°C. Furthermore, although there is no particular preferred upper limit to the 5% weight loss temperature after curing of the curable resin composition of the present invention, the substantial upper limit is 405°C.

[0052] The curable resin composition of the present invention can be used in a wide range of applications, such as adhesives for printed wiring boards, adhesives for coverlays of flexible printed circuit boards, copper-clad laminates, adhesives for semiconductor bonding, interlayer insulating materials, prepregs, sealants for LEDs, adhesives for structural materials, and sealants for display elements. In particular, the curable resin composition of the present invention has excellent coatability, low dielectric properties after curing, and heat resistance, and therefore can be suitably used as a sealant for display elements that require these properties. A sealant for display elements obtained using the curable resin composition of the present invention also constitutes the present invention. A sealant for organic EL display elements is particularly suitable as the sealant for display elements of the present invention. [Effects of the Invention]

[0053] According to the present invention, it is possible to provide a curable resin composition that has excellent coatability, low dielectric properties, and heat resistance after curing. Furthermore, according to the present invention, it is possible to provide a sealant for display elements that uses the curable resin composition. DETAILED DESCRIPTION OF THE INVENTION

[0054] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0055] (Examples 1 to 7, Comparative Examples 1 to 5) According to the compounding ratios shown in Tables 1 and 2, each material was uniformly stirred and mixed using a homodisper type stirring mixer at a stirring speed of 3000 rpm to prepare each of the curable resin compositions of Examples 1 to 7 and Comparative Examples 1 to 5.

[0056] <Evaluation> The curable resin compositions obtained in the examples and comparative examples were evaluated as follows, and the results are shown in Tables 1 and 2.

[0057] (Applicability) The viscosity of the obtained curable resin composition was measured using an E-type viscometer with a CP1 type cone plate at 25°C and 100 rpm. The E-type viscometer used was a VISCOMETER TV-22 (manufactured by Toki Sangyo Co., Ltd.). The coating properties were evaluated according to the following criteria. ○: No solid precipitation and viscosity of 300 mPa·s or less △: No solid precipitation occurs, but viscosity exceeds 300 mPa·s ×: When solid precipitation is confirmed

[0058] (low dielectric properties) The obtained curable resin composition was poured into a PTFE mold having a width of 2 mm, a length of 80 mm, and a depth of 200 μm, taking care to prevent air from getting in. The mold into which the composition was poured was irradiated with an LED UV lamp at a wavelength of 365 nm and an illuminance of 100 mW / cm. 2 UV rays of 3000mJ / cm 2 The curable resin composition was cured by irradiating the cured product. The dielectric constant of the obtained cured product was measured at 23°C and a frequency of 1.0 GHz by the cavity resonance method using a cavity resonance perturbation dielectric constant measurement device CP521 (manufactured by Kanto Electronics Application Development Co., Ltd.) and a network analyzer N5224A PNA (manufactured by Keysight Technologies, Inc.). Note that for the curable resin compositions of comparative examples that were evaluated as × in the above "(Coatability)", the dielectric constant of the cured product was not measured. The low dielectric properties were evaluated according to the following criteria. ○: When the relative dielectric constant is 2.5 or less △: When the relative dielectric constant is greater than 2.5 and less than 3.0 ×: When the relative dielectric constant exceeds 3.0

[0059] (Heat resistance) The obtained curable resin composition was poured into a PTFE mold having a width of 2 mm, a length of 80 mm, and a depth of 200 μm, taking care to prevent air from getting in. The mold into which the composition was poured was irradiated with an LED UV lamp at a wavelength of 365 nm and an illuminance of 100 mW / cm. 2 UV rays of 3000mJ / cm 2The curable resin composition was cured by irradiating the cured product. Dynamic viscoelasticity measurement was performed on the obtained cured product using a dynamic viscoelasticity measuring device (manufactured by IT Measurement & Control Co., Ltd., "DVA-200") under conditions of a gripping width of 24 mm, a heating rate of 10°C / min, and a frequency of 10 Hz in the range of 25°C to 250°C, and the temperature at which the loss tangent (tan δ) reached its maximum value was determined as the glass transition temperature. Note that for the curable resin compositions of comparative examples that were evaluated as "×" in the above "(Coatability)", the glass transition temperature of the cured product was not measured. The heat resistance was evaluated according to the following criteria. ○: Glass transition temperature is 140°C or higher △: Glass transition temperature is 100℃ or higher but less than 140℃ ×: Glass transition temperature is less than 100°C

[0060] [Table 1]

[0061] [Table 2] [Industrial Applicability]

[0062] According to the present invention, it is possible to provide a curable resin composition that has excellent coatability, low dielectric properties, and heat resistance after curing. Furthermore, according to the present invention, it is possible to provide a sealant for display elements that uses the curable resin composition.

Claims

1. The composition contains an aliphatic bismaleimide compound, a monomaleimide compound, a compound having a vinyloxy group, and a polymerization initiator, the content of the compound having a vinyloxy group is 10 parts by mass or more and 30 parts by mass or less based on 100 parts by mass of the total of the aliphatic bismaleimide compound, the monomaleimide compound, and the compound having a vinyloxy group, Contains no solvent or 0.05% by mass or less of solvent A curable resin composition comprising:

2. 2. The curable resin composition according to claim 1, wherein the content of the aliphatic bismaleimide compound is 10 parts by mass or more and 89 parts by mass or less based on 100 parts by mass of the total of the aliphatic bismaleimide compound, the monomaleimide compound, and the compound having a vinyloxy group.

3. 3. The curable resin composition according to claim 1, wherein the aliphatic bismaleimide compound has a molecular weight of 880 or more and 5,550 or less.

4. The curable resin composition according to claim 1 or 2, wherein the aliphatic bismaleimide compound has 40 or more and 360 or less carbon atoms.

5. A sealant for display elements, which is obtained by using the curable resin composition according to claim 1 or 2.

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