Sealant, cured body, display device, manufacturing method for display device, solar cell, and composition

Abstract

This invention relates to a sealant comprising a cationic polymerizable compound (A), a cationic polymerization initiator (B), and a curing retarder (X), wherein in a viscosity measurement performed under the following measurement conditions 1, the viscosity 20 seconds after the start of the measurement is defined as V. 0. Thirty seconds after the start of the measurement, a 365 nm wavelength, 30 mW / cm² light source is perpendicularly irradiated towards the alkali-free glass plate from a position 15 cm away for 20 seconds. 2% ultraviolet radiation (total 600 mJ / cm) 2) Let the viscosity 60 seconds after the end of the above ultraviolet irradiation be V. At 1 o'clock, by V 1 / V 0 represents a viscosity change rate greater than 1.00 but less than 1.75.

Description

Technical Field

[0001] The present invention relates to a sealant, a hardened body, a display device, a method for manufacturing the display device, a solar cell and a composition. Prior Art

[0002] In recent years, research on organic optical devices using organic thin-film elements, such as organic electroluminescent (OLED) displays and organic thin-film solar cells, has been advancing. Organic thin-film elements can be easily produced by vacuum deposition, solution coating, and other methods, resulting in excellent productivity.

[0003] An organic electroluminescent display device comprises a thin-film structure in which an organic light-emitting material layer is sandwiched between a pair of opposing electrodes. Electrons are injected into the organic light-emitting material layer from one electrode, and holes are injected into the layer from the other electrode. The electrons and holes combine within the organic light-emitting material layer, generating spontaneous light. Compared to liquid crystal displays (LCDs), which require backlights, organic electroluminescent displays offer advantages such as improved visibility, thinner design, and the ability to operate with low DC voltages. However, exposure of the organic light-emitting material layer or electrodes to ambient air can lead to a dramatic deterioration in luminescence properties and shortened lifespan. Therefore, sealing technology to prevent atmospheric moisture and oxygen from entering the organic light-emitting material layer or electrodes has become essential to improve the stability and durability of organic light-emitting display devices.

[0004] As technologies regarding such sealants for organic electroluminescent elements, for example, those described in Patent Document 1 (International Publication No. 2020 / 171186) and Patent Document 2 (International Publication No. 2020 / 067046) can be cited.

[0005] Patent Document 1 describes a composition comprising (A) a cationically polymerizable compound, (B) a cationic photopolymerization initiator, and (C) one or more phosphoric acid compounds selected from the group consisting of phosphoric acid esters and phosphites, wherein the cationically polymerizable compound (A) comprises (A-1) an alicyclic compound having an epoxy group and (A-2) an aromatic compound having an epoxy group, the aromatic compound (A-2) having an epoxy group comprises (A-2-1) a bisphenol A epoxy resin and (A-2-2) a bisphenol F epoxy resin, and the ratio A1 / A2 (mass ratio) of the content A1 of the bisphenol A epoxy resin (A-2-1) to the content A2 of the bisphenol F epoxy resin (A-2-2) is 0.2 to 5. The composition exhibits a minimal increase in viscosity after light irradiation and is suitable for use as a sealant for organic electroluminescent devices, with little tendency to deteriorate the organic electroluminescent device.

[0006] Patent Document 2 describes a sealant for an organic electroluminescent display element comprising: a cationic polymerizable compound containing an alicyclic compound having an epoxy group and an aromatic compound having an epoxy group; a cationic photopolymerization initiator; and two or more curing retarders selected from the group consisting of a phosphate-based curing retarder, an ether-based curing retarder, a metal complex-based curing retarder, and a nitroxide-based curing retarder; wherein the phosphate-based curing retarder is selected from the group consisting of phosphates and phosphites. The sealant for an organic electroluminescent display element has a sufficiently long service life after light irradiation, a moderate increase in viscosity after light irradiation, and easy adhesion, and excellent reliability after curing. Prior Art Literature Patent Literature

[0007] Patent Document 1: International Publication No. 2020 / 171186 Patent Document 2: International Publication No. 2020 / 067046 Summary of the Invention

[0008] [Problems to be solved by the invention]

[0009] As a sealant, it is preferred that uneven coating does not easily occur on concave and convex substrates such as color filters or substrates with light-emitting diode elements (TFT substrates). The present invention is completed in view of the above situation and provides a sealant and composition with improved coating properties on concave-convex substrates, a display device using the sealant, and a solar cell using the sealant. [Technical means to solve the problem]

[0010] The present inventors have conducted intensive research to achieve the above-mentioned objectives. As a result, they discovered that by controlling the viscosity change rate before and after ultraviolet irradiation within a specific range, the coating properties on uneven substrates can be improved, leading to the completion of the present invention.

[0011] According to the present invention, a sealant, a cured body, a display device, a method for manufacturing a display device, a solar cell, and a composition are provided below.

[0012] [1] A sealant comprising a cationic polymerizable compound (A), a cationic polymerization initiator (B), and a curing retarder (X), and In a viscosity measurement conducted under the following measurement condition 1, with the viscosity at 20 seconds from the start of the measurement being designated as V0, and 30 seconds from the start of the measurement, the alkali-free glass plate is vertically irradiated with ultraviolet light having a wavelength of 365 nm and a power of 30 mW / cm2 (a total of 600 mJ / cm2) for 20 seconds from a position 15 cm from the start of the measurement, and the viscosity at 60 seconds from the end of the ultraviolet irradiation being designated as V1, the rate of viscosity change represented by V1 / V0 is not less than 1.00 and not more than 1.75. <Measurement Condition 1> Device: Rheometer Temperature: 25℃ Geometry (top side): 8 mm diameter ,Aluminum parallel plates Plate (bottom): diameter 38 mm , alkali-free glass plate Shear speed: 1 min -1 Pitch: 0.05 mm Sample size: 20 mg Atmosphere: Nitrogen flow [2] The sealant as described in [1] above, wherein the viscosity V0 is greater than or equal to 1 mPa·s and less than or equal to 1000 mPa·s. [3] The sealant as described in [1] or [2] above, wherein the viscosity V1 is greater than or equal to 1 mPa·s and less than or equal to 2000 mPa·s. [4] The sealant as described in any one of [1] to [3] above, wherein the cationically polymerizable compound (A) contains an epoxy group. [5] The sealant as described in any one of [1] to [4] above, wherein the cationic polymerizable compound (A) comprises one or more selected from the group consisting of an alicyclic compound (A-1) having an epoxy group, an aromatic compound (A-2) having an epoxy group, and a glycidyl ether compound (A-3). [6] The sealant as described in any one of [1] to [5] above, wherein the cationically polymerizable compound (A) contains a bromine atom. [7] The sealant as described in any one of [1] to [6] above, wherein in the viscosity measurement performed under the measurement condition 1, the viscosity V2 10 minutes after the end of the ultraviolet irradiation is 5000 mPa·s or less. [8] The sealant as described in any one of [1] to [7] above, wherein the liquid specific gravity at 25°C is 1.10 or greater. [9] The sealant as described in any one of the above [1] to [8], wherein the static surface tension obtained by the hanging drop method is 50 mN / m or less.

[10] The sealant as described in any one of items [1] to [9] above, wherein the cationic polymerization initiator (B) comprises one or more selected from the group consisting of a cationic photopolymerization initiator (B1) and a cationic thermal polymerization initiator (B2).

[11] The sealant as described in any one of [1] to

[10] above, wherein the cationic polymerization initiator (B) contains an onium salt compound.

[12] The sealant as described in any one of [1] to

[11] above, wherein the content of the cationic polymerization initiator (B) is 0.01 parts by mass or more and 5.0 parts by mass or less relative to 100 parts by mass of the cationic polymerizable compound (A).

[13] The sealant as described in any one of items [1] to

[12] above, wherein the curing retarder (X) comprises one or more selected from the group consisting of a phosphate-based curing retarder, an ether-based curing retarder, a sulfide-based curing retarder, a metal complex-based curing retarder, and a nitroxide-based curing retarder.

[14] The sealant as described in any one of [1] to

[13] above, wherein the content of the curing retarder (X) is 0.10 parts by mass or more and 10.0 parts by mass or less relative to 100 parts by mass of the cationically polymerizable compound (A).

[15] The sealant as described in any one of [1] to

[14] above is used for a light-emitting diode element.

[16] A sealant as described in any one of [1] to

[15] above, which is used for bonding a color filter to an organic electroluminescent display element or for bonding a color filter to a micro LED (Light Emitting Diode).

[17] The sealant described in any one of [1] to

[14] above can be used to seal solar cells.

[18] The sealant as described in

[17] above, wherein the solar cell comprises a perovskite solar cell.

[19] A hardened body formed by hardening the sealant described in any one of items [1] to

[18] above.

[20] A display device comprises: a light-emitting diode element, a substrate, and a hardened sealing layer formed by the hardened body described in

[19] above and located between the light-emitting diode element and the substrate. [twenty one] A display device as described in

[20] above, wherein the light-emitting diode element comprises an organic electroluminescent display element or a micro-LED. [twenty two] A display device as described in

[20] or

[21] above, wherein the substrate includes a color filter. [twenty three] A method for manufacturing a display device, comprising: a coating step of coating the sealant as described in any one of items [1] to

[16] above on the first component; an irradiation step of irradiating the applied sealant with light; and The bonding step is to bond the first component to the second component via the sealant irradiated with light. [twenty four] A method for manufacturing a display device as described in

[23] above, wherein one of the first component and the second component is a substrate and the other is a light-emitting diode element.

[25] A method for manufacturing a display device as described in

[24] above, wherein the light-emitting diode element comprises an organic electroluminescent display element or a micro-LED.

[26] A method for manufacturing a display device as described in

[24] or

[25] above, wherein the substrate includes a color filter.

[27] A solar cell comprising: a solar cell cell, a substrate, and a hardened sealing layer located between the solar cell cell and the substrate and comprising a hardened body as described in

[19] above.

[28] The solar cell as described in

[27] above, wherein the solar cell cell comprises a perovskite solar cell cell.

[29] A composition comprising a cationic polymerizable compound (A), a cationic polymerization initiator (B), and a hardening retarder (X), and In a viscosity measurement conducted under the following measurement condition 1, with the viscosity at 20 seconds from the start of the measurement being designated as V0, and 30 seconds from the start of the measurement, the alkali-free glass plate is vertically irradiated with ultraviolet light having a wavelength of 365 nm and a power of 30 mW / cm2 (a total of 600 mJ / cm2) for 20 seconds from a position 15 cm from the start of the measurement, and the viscosity at 60 seconds from the end of the ultraviolet irradiation being designated as V1, the rate of viscosity change represented by V1 / V0 is not less than 1.00 and not more than 1.75. <Measurement Condition 1> Device: Rheometer Temperature: 25℃ Geometry (top side): 8 mm diameter ,Aluminum parallel plates Plate (bottom): diameter 38 mm , alkali-free glass plate Shear speed: 1 min -1 Pitch: 0.05 mm Sample size: 20 mg Atmosphere: Nitrogen flow [Effects of the Invention]

[0013] According to the present invention, a sealant and a composition having improved coating properties on a concave-convex substrate, a display device using the sealant, and a solar cell using the sealant can be provided. Implementation Method

[0014] The following describes the embodiments of the present invention in detail. Furthermore, unless otherwise stated, the "~" between numbers in the text represents above to below.

[0015] 1. Sealant The sealant of this embodiment comprises a cationically polymerizable compound (A), a cationic polymerization initiator (B), and a curing retarder (X). In a viscosity measurement conducted under the following measurement condition 1, the viscosity 20 seconds after the start of the measurement is defined as V0. 30 seconds after the start of the measurement, the sealant is irradiated perpendicularly with ultraviolet light having a wavelength of 365 nm and a power of 30 mW / cm2 (a total of 600 mJ / cm2) for 20 seconds from a position 15 cm from the start of the measurement toward the alkali-free glass plate. 60 seconds after the end of the ultraviolet irradiation is defined as V1. The viscosity change rate represented by V1 / V0 is 1.00 or greater and less than 1.75.

[0016] <Measurement Condition 1> Device: Rheometer (viscoelasticity measuring device) Temperature: 25℃ Geometry (jig) (upper side): 8 mm diameter ,Aluminum parallel plates Plate (bottom): diameter 38 mm , alkali-free glass plate Shear speed: 1 min -1 Pitch: 0.05 mm Sample size: 20 mg Atmosphere: Nitrogen flow

[0017] The sealant of this embodiment, by maintaining the viscosity change rate represented by V1 / V0 within the aforementioned range, can improve coating properties on concave-convex substrates such as color filters or substrates with light-emitting diodes (TFT substrates). The sealant of this embodiment can be easily spread without uneven coating on concave-convex substrates, thereby suppressing the presence of bubbles in the coating film. As a result, a hardened sealant layer with enhanced transparency can be formed on the concave-convex substrate.

[0018] The sealant of this embodiment is controlled so that the viscosity change rate, represented by V1 / V0, is greater than 1.00 and less than 1.75. This improves the sealant's coating properties on uneven substrates. The reason for this is unclear, but the following are considered. First, it is believed that by keeping the viscosity change rate represented by V1 / V0 above the lower limit, it is possible to suppress uneven film thickness caused by excessive wetting and spreading of the applied droplet. Furthermore, it is believed that by keeping the viscosity change rate represented by V1 / V0 below the upper limit, wetting and spreading are facilitated on the uneven surface of the substrate, thereby suppressing the presence of bubbles in the coated film and uneven film thickness. Here, in order to adjust the viscosity change rate represented by V1 / V0 within the above range, it is important to, for example, appropriately select the types of the cationic polymerizable compound (A), cationic polymerization initiator (B), and curing retarder (X) that constitute the sealant of this embodiment, and appropriately adjust the content ratio of each component; after mixing the components, add molecular sieves, let it stand for dehydration, and then filter; and manufacture under a "yellow light environment" with a short wavelength cutoff of 500 nm or less (500 nm or less) to suppress unintended polymerization.

[0019] The viscosity change rate of the sealant of this embodiment, represented by V1 / V0, is greater than 1.00 and less than 1.75. From the perspective of further improving the coating properties on concave and convex substrates, it is preferably less than 1.74, more preferably less than 1.73, further preferably less than 1.70, further preferably less than 1.65, and particularly preferably less than 1.60.

[0020] From the perspective of further improving the performance balance between the coating properties of the sealant of this embodiment on the concave-convex substrate and the flowability during coating, the viscosity V0 of the sealant of this embodiment is preferably 1 mPa·s or more, more preferably 10 mPa·s or more, further preferably 50 mPa·s or more, further preferably 70 mPa·s or more, particularly preferably 100 mPa·s or more, further particularly preferably 150 mPa·s or more, and preferably 1000 mPa·s or less, more preferably 800 mPa·s or less, further preferably 500 mPa·s or less, further preferably 300 mPa·s or less, and particularly preferably 250 mPa·s or less.

[0021] From the viewpoint of further improving the performance balance of the sealant of this embodiment in terms of the coating properties on the concave-convex substrate and the flow properties during coating, and from the viewpoint of obtaining a longer service life, the viscosity V1 of the sealant of this embodiment is preferably 1 mPa·s or more, more preferably 10 mPa·s or more, further preferably 50 mPa·s or more, further preferably 70 mPa·s or more, particularly preferably 100 mPa·s or more, further particularly preferably 150 mPa·s or more, and preferably 2000 mPa·s or less, more preferably 1500 mPa·s or less, further preferably 1000 mPa·s or less, further preferably 800 mPa·s or less, particularly preferably 600 mPa·s or less, and further particularly preferably 500 mPa·s or less.

[0022] From the perspective of further improving the performance balance of the sealant of this embodiment in terms of coating properties on the concave-convex substrate and flow properties during coating, and from the perspective of obtaining a longer service life, in the viscosity measurement performed by the above-mentioned measurement condition 1, the viscosity V2 10 minutes after the end of the above-mentioned ultraviolet irradiation is preferably 10 mPa·s or more, more preferably 20 mPa·s or more, further preferably 100 mPa·s or more, further preferably 150 mPa·s or more, particularly preferably 200 mPa·s or more, further particularly preferably 300 mPa·s or more, and preferably 5000 mPa·s or less, more preferably 4000 mPa·s or less, further preferably 3000 mPa·s or less, further preferably 2000 mPa·s or less, particularly preferably 1800 mPa·s or less, further particularly preferably 1500 mPa·s or less, and particularly preferably 1200 mPa·s or less. mPa·s or less, more preferably 1000 mPa·s or less, and most preferably 600 mPa·s or less.

[0023] The sealant of this embodiment has good coating properties on concave-convex substrates and can therefore be preferably used as a sealant for light-emitting diode elements, and can even be more preferably used as a sealant for organic electroluminescent display elements. It can further be preferably used for bonding color filters to organic electroluminescent display elements or bonding color filters to micro-LEDs.

[0024] The sealant of this embodiment is preferably used to seal a solar cell. The solar cell of this embodiment is preferably a perovskite solar cell.

[0025] Hereinafter, each component of the sealant according to this embodiment will be described.

[0026] (Component (A): cationically polymerizable compound) Component (A) is a cationically polymerizable compound, also referred to as a compound having a cationically polymerizable group. Examples of cationically polymerizable groups include cyclic ether groups such as epoxy groups (oxirane rings) and oxetane groups (oxetane rings); and cationically polymerizable vinyl groups. Component (A) preferably contains an epoxy group. Furthermore, component (A) is preferably photopolymerizable. That is, component (A) preferably comprises one or more selected from the group consisting of epoxy compounds, oxetane compounds, and cationic polymerizable vinyl compounds, and more preferably comprises an epoxy compound. Examples of the epoxy compound include an alicyclic compound (A-1) having an epoxy group (alicyclic epoxy compound), an aromatic compound (A-2) having an epoxy group (aromatic epoxy compound), and a glycidyl ether compound (A-3).

[0027] Component (A) may be a compound having one cationically polymerizable group or a compound having two or more cationically polymerizable groups. Component (A) preferably has two or more cationically polymerizable groups, more preferably two cationically polymerizable groups.

[0028] From the perspective of further improving the coating properties on concavo-convex substrates and further improving the performance balance between the adhesion and transparency of the obtained cured product, component (A) preferably includes one or more selected from the group consisting of an alicyclic compound (A-1) having an epoxy group, an aromatic compound (A-2) having an epoxy group, and a glycidyl ether compound (A-3), and more preferably includes an alicyclic compound (A-1) having an epoxy group, an aromatic compound (A-2) having an epoxy group, and a glycidyl ether compound (A-3). Furthermore, from the perspective of further improving the coating properties on the concavo-convex substrate, the component (A) preferably contains a bromine atom. Here, the component (A) containing a bromine atom means containing a compound containing a bromine atom.

[0029] <Component (A1): Alicyclic Compound Having an Epoxy Group> Component (A1) is a compound having an epoxy group and an alicyclic group. Component (A1) may be a compound having one epoxy group or a compound having two or more epoxy groups. Component (A1) preferably has two or more epoxy groups, more preferably two epoxy groups. Component (A1) may be a compound without an aromatic ring. Component (A1) may be used alone or in combination of two or more.

[0030] Component (A1) may be, for example, a compound obtained by epoxidizing a compound having a cycloolefin ring, or a derivative thereof. Examples of cycloolefin rings include cyclohexene, cyclopentene, and pinene. Epoxidation can be performed using an oxidizing agent. Examples of oxidizing agents include hydrogen peroxide and peracids. Examples of such component (A1) include one or more selected from the group consisting of 3',4'-epoxycyclohexylmethyl 3,4-epoxycyclohexylcarboxylate, 3,4-epoxycyclohexylalkyl (meth)acrylates (e.g., 3,4-epoxycyclohexylmethyl (meth)acrylate), and (3,3',4,4'-diepoxy)bicyclohexane.

[0031] Component (A1) can be, for example, a compound obtained by hydrogenating a compound having an epoxy group and an aromatic ring, or a derivative thereof. Examples of compounds having an epoxy group and an aromatic ring include bisphenol A epoxy resin and bisphenol F epoxy resin. Examples of such component (A-1) include hydrogenated bisphenol A epoxy resin and hydrogenated bisphenol F epoxy resin.

[0032] Component (A1) is preferably a compound having a 1,2-epoxycyclohexane structure. For example, a compound represented by formula (A1-1) is preferred as the compound having a 1,2-epoxycyclohexane structure.

[0033] [Chemistry 1]

[0034] In formula (A1-1), X represents a single bond or a linking group (a divalent group having one or more atoms).

[0035] When X is a single bond, the compound represented by formula (A1-1) is (3,3',4,4'-diepoxy)bicyclohexane.

[0036] The linking group may be, for example, a divalent hydrocarbon group, a carbonyl group, an ether bond, an ester bond, a carbonate group, an amide bond, or a combination of these groups. X is preferably a linking group. The linking group is preferably a group having an ester bond, more preferably a group formed by linking an ester bond and a divalent hydrocarbon group. Examples of compounds containing a group having an ester bond as a linking group include 3',4'-epoxycyclohexylmethyl 3,4-epoxycyclohexylcarboxylate (molecular weight 252).

[0037] The divalent hydrocarbon group is preferably an alkanediyl group, more preferably an alkanediyl group having 1 to 3 carbon atoms.

[0038] The compound represented by formula (A1-1) is preferably 3',4'-epoxycyclohexylmethyl 3,4-epoxycyclohexylcarboxylate.

[0039] From the perspective of further improving the performance balance among the sealant's coatability on uneven substrates, the sealant's storage stability, and the moisture resistance of the cured product, the molecular weight of component (A1) is preferably 450 or less, more preferably 400 or less, even more preferably 300 or less, and even more preferably 280 or less. Furthermore, the molecular weight of component (A1) may be, for example, 100 or greater, 150 or greater, or even 200 or greater.

[0040] When component (A1) has a molecular weight distribution, the number average molecular weight of component (A1) is preferably within the above range. Furthermore, in this specification, the number average molecular weight represents a polystyrene-equivalent value measured by gel permeation chromatography (GPC) under the following measurement conditions. Solvent (mobile phase): THF (tetrahydrofuran) Degassing device: ERC-3310 manufactured by ERMA Pump: PU-980 manufactured by Nippon Spectrophotometer Flow rate: 1.0 ml / min Automatic sampler: AS-8020 manufactured by Tosoh Corporation Column oven: L-5030 manufactured by Hitachi, Ltd. Set temperature: 40℃ Column composition: 2 TSK guard columns MP (×L) 6.0 mm ID × 4.0 cm manufactured by Tosoh Corporation, and 2 TSK-GELMULTIPORE HXL-M 7.8 mm ID × 30.0 cm manufactured by Tosoh Corporation, for a total of 4 columns Detector: RI (refractive index) L-3350 manufactured by Hitachi Ltd. Data processing: SIC480 data station

[0041] <Component (A2): Aromatic compound having an epoxy group> Component (A2) is a compound having an epoxy group and an aromatic ring. Component (A2) may be a compound having one epoxy group or a compound having two or more epoxy groups. Component (A2) preferably has two or more epoxy groups, more preferably two epoxy groups. Component (A2) may also be a compound without an alicyclic group. Component (A2) may be used alone or in combination of two or more.

[0042] Component (A2) can be any monomer, oligomer, or polymer. Examples thereof include one or more selected from the group consisting of bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin, biphenyl epoxy resin, naphthalene epoxy resin, fluorene epoxy resin, novolac phenol epoxy resin, cresol novolac epoxy resin, and modified products thereof. Furthermore, component (A2) can be one or more selected from the group consisting of halogenated phenyl glycidyl ethers such as bromophenyl glycidyl ether and dibromophenyl glycidyl ether; and bromine-containing aromatic epoxy compounds such as brominated bisphenol A epoxy resin, brominated bisphenol F novolac epoxy resin, and brominated phenol novolac epoxy resin. Halogenated phenyl glycidyl ether is preferred as the aromatic epoxy compound containing bromine atoms. As the halophenyl glycidyl ether, dibromophenyl glycidyl ether is preferred.

[0043] The (A2) component preferably includes one or more compounds selected from the group consisting of compounds having a bisphenol structure (for example, a bisphenol A structure, a bisphenol F structure, a bisphenol S structure, etc.) and aromatic epoxy compounds containing bromine atoms, more preferably includes one or more compounds selected from the group consisting of bisphenol A epoxy resin, bisphenol F epoxy resin and halophenyl glycidyl ether, further preferably includes one or more compounds selected from the group consisting of bisphenol A epoxy resin, bisphenol F epoxy resin and dibromophenyl glycidyl ether, further preferably includes at least one compound selected from the group consisting of bisphenol F epoxy resin and dibromophenyl glycidyl ether.

[0044] From the perspective of further improving the performance balance of the sealant's coating properties on concave-convex substrates, the sealant's storage stability, and the moisture resistance of the cured product, the molecular weight of component (A2) is preferably 100 or more, more preferably 150 or more, and further preferably 200 or more, and is preferably 5000 or less, more preferably 1000 or less, and further preferably 450 or less.

[0045] When component (A2) has a molecular weight distribution, the number average molecular weight of component (A2) is preferably within the above range. Furthermore, in this specification, the number average molecular weight represents the polystyrene-equivalent value measured by gel permeation chromatography (GPC) under the above-described measurement conditions.

[0046] <Component (A3): Glycidyl Ether Compound> Component (A3) is a compound having a glycidyl ether group. Component (A3) may be a compound having one epoxy group or a compound having two or more epoxy groups. Component (A3) preferably has two or more epoxy groups, more preferably two epoxy groups. Component (A3) may also be a compound without an alicyclic group or an aromatic ring. Component (A3) may be used alone or in combination of two or more. Component (A3) is preferably different from component (A1) and component (A2).

[0047] The component (A3) is preferably a diglycidyl ether compound. From the perspective of further improving the coating properties of the sealant on the concave-convex substrate, the diglycidyl ether compound preferably includes one or more diglycidyl ethers of alkylene glycols such as diglycidyl ether of ethylene glycol, diglycidyl ether of propylene glycol, diglycidyl ether of 1,6-hexanediol, and diglycidyl ether of neopentyl glycol; polyglycidyl ethers of polyols such as diglycidyl ether or triglycidyl ether of glycerol or its alkylene oxide adducts; and diglycidyl ethers of polyalkylene glycols such as diglycidyl ether of polyethylene glycol or its alkylene oxide adducts, and diglycidyl ether of polypropylene glycol or its alkylene oxide adducts. It is more preferable to include diglycidyl ethers of alkylene glycols. The diglycidyl ether of alkylene glycol is preferably one or more selected from the group consisting of diglycidyl ether of ethylene glycol, diglycidyl ether of propylene glycol, diglycidyl ether of 1,6-hexanediol, and diglycidyl ether of neopentyl glycol, and more preferably one or two selected from the group consisting of diglycidyl ether of 1,6-hexanediol and diglycidyl ether of neopentyl glycol. Examples of the alkylene glycol include ethylene glycol, propylene glycol, 1,6-hexanediol, and neopentyl glycol. Examples of the polyalkylene glycol include polyethylene glycol or its alkylene oxide adducts, polypropylene glycol or its alkylene oxide adducts, and the like. Examples of the alkylene oxide include ethylene oxide and propylene oxide.

[0048] Regarding the content of the component (A1) in the sealant of the present embodiment, from the viewpoint of further improving the performance balance between the coating properties of the sealant on the concave-convex substrate and the durability of the cured body, when the total amount of the component (A) in the sealant of the present embodiment is set to 100 parts by mass, it is preferably 10.0 parts by mass or more, more preferably 15.0 parts by mass or more, further preferably 18.0 parts by mass or more, further preferably 30.0 parts by mass or more, particularly preferably 40.0 parts by mass or more, further particularly preferably 50.0 parts by mass or more, particularly preferably 55.0 parts by mass or more, and most preferably 60.0 parts by mass or more, and preferably 90.0 parts by mass or less, more preferably 85.0 parts by mass or less, further preferably 80.0 parts by mass or less, and further preferably 75.0 parts by mass or less.

[0049] Regarding the content of the component (A2) in the sealant of the present embodiment, from the viewpoint of further improving the performance balance between the coating properties of the sealant on the concave-convex substrate and the durability of the cured body, when the total amount of the component (A) in the sealant of the present embodiment is set to 100 parts by mass, it is preferably 5.0 parts by mass or more, more preferably 10.0 parts by mass or more, further preferably 15.0 parts by mass or more, further preferably 20.0 parts by mass or more, and particularly preferably 25.0 parts by mass or more, and is preferably 65.0 parts by mass or less, more preferably 60.0 parts by mass or less, further preferably 55.0 parts by mass or less, further preferably 50.0 parts by mass or less, and particularly preferably 45.0 parts by mass or less.

[0050] Regarding the content of the component (A3) in the sealant of the present embodiment, from the viewpoint of further improving the performance balance between the coating properties of the sealant on the concave-convex substrate and the durability of the cured product, when the total amount of the component (A) in the sealant of the present embodiment is set to 100 parts by mass, it is preferably 0.1 parts by mass or more, more preferably 0.2 parts by mass or more, further preferably 0.5 parts by mass or more, further preferably 1.0 parts by mass or more, particularly preferably 1.5 parts by mass or more, and preferably 90.0 parts by mass or less, more preferably 85.0 parts by mass or less, further preferably 82.0 parts by mass or less, further preferably 20.0 parts by mass or less, particularly preferably 15.0 parts by mass or less, further preferably 10.0 parts by mass or less, particularly preferably 5.0 parts by mass or less, and most preferably 3.0 parts by mass or less.

[0051] When the total amount of component (A) in the sealant of this embodiment is 100 parts by mass, the total content of components (A1), (A2), and (A3) in the sealant of this embodiment is preferably 60 parts by mass or more, more preferably 70 parts by mass or more, further preferably 80 parts by mass or more, further preferably 95 parts by mass or more, further preferably 98 parts by mass or more, and may also be 100 parts by mass.

[0052] ((B) Cationic polymerization initiator) Component (B) may be one or more selected from the group consisting of a cationic photopolymerization initiator capable of initiating cationic polymerization of component (A) by light activation, and a cationic thermal polymerization initiator capable of initiating cationic polymerization of component (A) by heat activation, preferably a cationic photopolymerization initiator.

[0053] Examples of the cationic photopolymerization initiator include aryl iodonium salt derivatives (e.g., Cyracure UVI-6990 and Cyracure UVI-6974 manufactured by The Dow Chemical Company, Adeka Optomer SP-150, Adeka Optomer SP-152, Adeka Optomer SP-170, and Adeka Optomer SP-172 manufactured by ADEKA, CPI-100P, CPI-101A, CPI-200K, CPI-210S, CPI-310FG, and LW-S1 manufactured by San-Apro, and Ciba-Cure-1190 manufactured by Double Bond), aryl iodonium salt derivatives (e.g., Irgacure 250 and Rhodia manufactured by Ciba Specialty Chemicals), Japan RP-2074, etc.), allene-ion complex derivatives, diazonium salt derivatives, tri-ion initiators, other halides and other acid generators, etc.

[0054] Examples of cationic thermal polymerization initiators include any cationic thermal polymerization initiator that is activated by heating to induce the ring-opening of the ring-opening polymerizable group. Examples of cationic thermal polymerization initiators include onium salt compounds such as quaternary ammonium salts, phosphonium salts, and coronium salts. Examples of commercially available cationic thermal polymerization initiators include Adekaopton CP-66, Adekaopton CP-77 (manufactured by ADEKA Corporation), San-Aid SI-60L, San-Aid SI-80L, San-Aid SI-100L (manufactured by Sanshin Chemical Industry Co., Ltd.), and CI Series (manufactured by Nippon Soda Co., Ltd.).

[0055] From the perspective of more significantly achieving the aforementioned effects of using two or more hardening retardants, component (B) preferably contains an onium salt compound. The onium salt compound preferably contains one or more selected from the group consisting of aryl coronium salt derivatives, aryl iodonium salt derivatives, and diazonium salt derivatives, and more preferably contains an aryl coronium salt derivative. The anion preferably contains one or more selected from the group consisting of antimonates and gallates.

[0056] To facilitate mixing with other components such as component (A), component (B) may be pre-dissolved in a solvent. The solvent is not particularly limited, and examples thereof include carbonates such as propylene carbonate, ethylene carbonate, 1,2-butylene carbonate, dimethyl carbonate, and diethyl carbonate.

[0057] The content of component (B) in the sealant of this embodiment is preferably 0.01 parts by mass or more, more preferably 0.05 parts by mass or more, further preferably 0.10 parts by mass or more, further preferably 0.15 parts by mass or more, and particularly preferably 0.20 parts by mass or more, relative to 100 parts by mass of component (A), from the viewpoint of further improving the curability of the sealant. From the viewpoint of further improving the adhesive durability of the cured product, the content is preferably 5.0 parts by mass or less, more preferably 3.0 parts by mass or less, further preferably 2.0 parts by mass or less, further preferably 1.0 part by mass or less, particularly preferably 0.70 parts by mass or less, further particularly preferably 0.50 parts by mass or less, and particularly preferably 0.30 parts by mass or less.

[0058] ((X) ingredient: hardening retarder) The sealant of this embodiment contains a hardening retarder as the component (X). From the perspective of further improving the performance balance between the sealant's coating properties on the concave-convex substrate and the sealant's storage stability, the (X) component preferably includes one or more selected from the group consisting of a phosphate-based curing retarder (component (C)), an ether-based curing retarder (component (D)), a thioether-based curing retarder (component (E)), a metal complex-based curing retarder (component (F)), and a nitroxide-based curing retarder (component (G)), and more preferably includes one or more selected from the group consisting of a phosphate-based curing retarder (component (C)) and an ether-based curing retarder (component (D)).

[0059] The content of component (X) in the sealant of this embodiment is preferably 0.10 parts by mass or more, more preferably 0.20 parts by mass or more, further preferably 0.50 parts by mass or more, further preferably 0.80 parts by mass or more, and particularly preferably 1.0 parts by mass or more, relative to 100 parts by mass of component (A), from the viewpoint of achieving a longer service life. From the viewpoint of further improving the performance balance between moisture resistance and adhesion of the cured product, the content is preferably 10.0 parts by mass or less, more preferably 5.0 parts by mass or less, further preferably 2.0 parts by mass or less, and further preferably 1.5 parts by mass or less.

[0060] <Component (C): Phosphate-based Hardening Retardant> The phosphoric acid-based hardening retarder is a hardening retarder selected from the group consisting of phosphate esters (component (C1)) and phosphites (component (C2)). Component (C) may be used alone or in combination of two or more.

[0061] Examples of the component (C1) include benzyl diethyl phosphate, trimethyl phosphate, triethyl phosphate, tri-n-butyl phosphate, tris(butoxyethyl) phosphate, tris(2-ethylhexyl) phosphate, (RO) 3P═O (R is lauryl, cetyl, stearyl, or oleyl), tris(2-chloroethyl) phosphate, tris(2-dichloropropyl) phosphate, triphenyl phosphate, butyl pyrophosphate, tricresyl phosphate, tris(xylyl) phosphate, diphenyl octyl phosphate, diphenyl cresyl phosphate, ditolyl diphosphate, monobutyl phosphate, dibutyl phosphate, di-2-ethylhexyl phosphate, monoisodecyl phosphate, acidic ethyl ammonium phosphate, and 2-ethylhexyl acid phosphate salt. The component (C1) may be used alone or in combination of two or more.

[0062] From the perspective of moderate reactivity to cations and reduced outgassing, component (C1) preferably includes one or more compounds selected from the group consisting of compounds represented by formula (C1-1), compounds represented by formula (C1-2), and compounds represented by formula (C1-3), and more preferably includes a compound represented by formula (C1-2).

[0063] [Chemistry 2]

[0064] [Chemistry 3]

[0065] [Chemistry 4]

[0066] In formula (C1-1), formula (C1-2) and formula (C1-3), R 1, R 2, R 3, R 4, R 5 and R 6 each independently represent a hydrocarbon group which may have a substituent.

[0067] R 2, R 3 and R 4 in formula (C1-2), and R 5 and R 6 in formula (C1-3) are preferably the same group in each formula.

[0068] Examples of substituents that the hydrocarbon groups in R1, R2, R3, R4, R5, and R6 may have include oxyalkyl groups. The hydrocarbon groups in R1, R2, R3, R4, R5, and R6 are preferably unsubstituted hydrocarbon groups.

[0069] The hydrocarbon groups in R1, R2, R3, R4, R5, and R6 are preferably alkyl or aryl groups, more preferably alkyl or phenyl groups, and even more preferably alkyl groups. The number of carbon atoms in the alkyl group can be, for example, 1 to 18, preferably 4 to 13.

[0070] Examples of the compound represented by formula (C1-1) include monoalkyl phosphate (i.e., a compound in which R1 is an alkyl group), and specific examples include monoethyl phosphate, mono-n-butyl phosphate, mono(butoxyethyl) phosphate, and mono(2-ethylhexyl) phosphate.

[0071] The compound represented by formula (C1-2) is preferably a trialkyl phosphate (i.e., a compound in which R2, R3, and R4 are alkyl groups). In this case, the number of carbon atoms in the alkyl groups of R2, R3, and R4 is preferably 1 to 18, more preferably 4 to 12, and even more preferably 8.

[0072] Specific examples of trialkyl phosphates include triethyl phosphate, tri-n-butyl phosphate, tri(butoxyethyl) phosphate, tri(2-ethylhexyl) phosphate, (RO) 3P═O (R is lauryl, cetyl, stearyl, or oleyl), and the like.

[0073] Examples of the compound represented by formula (C1-3) include dialkyl phosphates (i.e., compounds in which R5 and R6 are alkyl groups). Specific examples of dialkyl phosphates include dibutyl phosphate and bis(2-ethylhexyl) phosphate.

[0074] Component (C2) is a phosphite. Examples of component (C2) include trimethyl phosphite, triethyl phosphite, tri-n-butyl phosphite, tri(2-ethylhexyl) phosphite, triisooctyl phosphite, tridecyl phosphite, triisodecyl phosphite, tritridecyl phosphite, trioleyl phosphite, tristearyl phosphite, triphenyl phosphite, tri(nonylphenyl) phosphite, tri(2,4-di-tert-butylphenyl) phosphite, phenyl diisooctyl phosphite, phenyl diisodecyl phosphite, diphenyl mono(2-ethylhexyl) phosphite, diphenyl isooctyl phosphite, diphenyl monodecyl phosphite, diphenyl monoisodecyl phosphite, diphenyl monotridecyl phosphite, and bis(nonylphenyl) phosphite. Dinonylphenyl ester, tetraphenyldipropylene glycol diphosphite, poly(dipropylene glycol)phenyl phosphite, diisodecyl pentaerythritol diphosphite, bis(tridecyl)pentaerythritol diphosphite, distearyl pentaerythritol diphosphite, bis(nonylphenyl)pentaerythritol diphosphite, tetraphenyltetra(tridecyl)pentaerythritol tetraphosphite, tetra(tridecyl)-4,4'-isopropylidene diphenyl phosphite, trilauryl trithiophosphite, dimethyl phosphite, dibutyl phosphite, di(2-ethylhexyl) phosphite, dilauryl phosphite, dioleyl phosphite, diphenyl phosphite, diphenyl mono(2-ethylhexyl) phosphite, diphenyl mono(tridecyl) phosphite, and diphenyl mono(tridecyl) phosphite. Component (C2) may be used alone or in combination of two or more.

[0075] From the perspective of moderate reactivity toward cations, component (C2) preferably includes one or more selected from the group consisting of a compound represented by formula (C2-1), a compound represented by formula (C2-2), a compound represented by formula (C2-3), a compound represented by formula (C2-4), a compound represented by formula (C2-5), and a compound represented by formula (C2-6).

[0076] [Chemistry 5]

[0077] [Chemistry 6]

[0078] [Chemistry 7]

[0079] [Chemistry 8]

[0080] [Chemistry 9]

[0081] [Chemistry 10]

[0082] In Formula (C2-1) to Formula (C2-6), R7, R8, R9, R10, R11, R12, R13, R14, R15, R16, and R17 each independently represent a hydrocarbon group which may have a substituent.

[0083] Examples of substituents that the hydrocarbon groups in R7, R8, R9, R10, R11, R12, R13, R14, R15, R16, and R17 may have include oxyalkyl groups. The hydrocarbon groups in R7, R8, R9, R10, R11, R12, R13, R14, R15, R16, and R17 are preferably unsubstituted hydrocarbon groups.

[0084] The hydrocarbon group in R7, R8, R9, R10, R11, R12, R13, R14, R15, R16, and R17 is preferably an alkyl group or an aryl group, more preferably an alkyl group or a phenyl group, and even more preferably an alkyl group. The number of carbon atoms in the alkyl group can be, for example, from 1 to 30, preferably from 1 to 18. The aryl group is preferably a phenyl group.

[0085] R 8 and R 9 in formula (C2-2), R 10, R 11, and R 12 in formula (C2-3), R 13 and R 14 in formula (C2-4), and R 15 and R 16 in formula (C2-5) are preferably the same in each formula.

[0086] Examples of the compound represented by formula (C2-1) include monoalkyl phosphites (ie, compounds in which R 7 is an alkyl group).

[0087] Examples of the compound represented by formula (C2-2) include dialkyl phosphites (ie, compounds in which R 8 and R 9 are alkyl groups).

[0088] Examples of the compound represented by formula (C2-3) include trialkyl phosphites (i.e., compounds in which R10, R11, and R12 are alkyl groups) and phenyl phosphites (i.e., compounds in which one or more of R10, R11, and R12 are phenyl groups). Specific examples of trialkyl phosphites include triethyl phosphite, tri(2-ethylhexyl) phosphite, tridecyl phosphite, trilauryl phosphite, tri(tridecyl) phosphite, and trioleyl phosphite. Specific examples of phenyl phosphites include diphenyl monodecyl phosphite.

[0089] Examples of the compound represented by formula (C2-4) include bis(alkyl)pentaerythritol diphosphites (i.e., compounds in which R 13 and R 14 are alkyl groups). Specific examples of the compound represented by formula (C2-4) include bis(decyl)pentaerythritol diphosphite, bis(tridecyl)pentaerythritol diphosphite, and distearylpentaerythritol diphosphite.

[0090] Examples of the compound represented by formula (C2-5) include dialkyl phosphites (i.e., compounds in which R 15 and R 16 are alkyl groups). Specific examples of the compound represented by formula (C2-5) include diethyl phosphite, bis(2-ethylhexyl) phosphite, dilauryl phosphite, and dioleyl phosphite.

[0091] Examples of the compound represented by formula (C2-6) include monoalkyl phosphites (i.e., compounds in which R is an alkyl group). Specific examples of the compound represented by formula (C2-6) include monoethyl phosphite, mono(2-ethylhexyl) phosphite, monolauryl phosphite, and monooleyl phosphite.

[0092] As component (C2), it is preferred that the component comprises a phosphate selected from trimethyl phosphite, triethyl phosphite, tri-n-butyl phosphite, tri(2-ethylhexyl) phosphite, triisooctyl phosphite, tridecyl phosphite, triisodecyl phosphite, tritridecyl phosphite, trioleyl phosphite, tristearyl phosphite, triphenyl phosphite, tri(nonylphenyl) phosphite, diisodecyl pentaerythritol diphosphite, bis(tridecyl) pentaerythritol diphosphite, distearyl pentaerythritol diphosphite, bis(nonylphenyl) pentaerythritol diphosphite , dimethyl phosphite, dibutyl phosphite, di(2-ethylhexyl) phosphite, dilauryl phosphite and dioleyl phosphite, more preferably one or more selected from the group consisting of trimethyl phosphite, triethyl phosphite, tri-n-butyl phosphite, tri(2-ethylhexyl) phosphite, triisooctyl phosphite, tridecyl phosphite, triisodecyl phosphite, tritridecyl phosphite, trioleyl phosphite, tristearyl phosphite, triphenyl phosphite and tri(nonylphenyl) phosphite.

[0093] When the sealant of the present embodiment contains component (C), the content of component (C) in the sealant of the present embodiment is preferably 0.001 parts by mass or more, more preferably 0.005 parts by mass or more, further preferably 0.01 parts by mass or more, further preferably 0.02 parts by mass or more, particularly preferably 0.05 parts by mass or more, further particularly preferably 0.10 parts by mass or more, and particularly preferably 0.20 parts by mass or more, relative to 100 parts by mass of component (A), from the viewpoint of obtaining a longer service life. From the viewpoint of further improving the performance balance between moisture resistance and adhesion of the cured product, the content of component (C) is preferably 5.0 parts by mass or less, more preferably 2.0 parts by mass or less, further preferably 1.0 parts by mass or less, and further preferably 0.5 parts by mass or less.

[0094] <Component (D): Ether-based Curing Retardant> Component (D) is a hardening retarder having an ether bond. Component (D) may be used alone or in combination of two or more.

[0095] Component (D) may be a chain ether or a cyclic ether. Examples of chain ethers include polyalkylene oxides such as polyethylene glycol, polypropylene glycol, and polyoxytetramethylene glycol. Examples of polyalkylene oxides include polyoxyethylene dimethyl ether. Examples of cyclic ethers include crown ethers. Examples of crown ethers include 18-crown-6-ether and 15-crown-5-ether.

[0096] From the viewpoint of appropriate reactivity to cations, the component (D) is preferably a cyclic ether, more preferably a crown ether, and even more preferably 18-crown-6-ether.

[0097] When the sealant of the present embodiment contains component (D), the content of component (D) in the sealant of the present embodiment is preferably 0.01 parts by mass or more, more preferably 0.02 parts by mass or more, further preferably 0.05 parts by mass or more, further preferably 0.10 parts by mass or more, particularly preferably 0.20 parts by mass or more, further particularly preferably 0.50 parts by mass or more, relative to 100 parts by mass of component (A), from the viewpoint of obtaining a longer service life. From the viewpoint of further improving the performance balance between moisture resistance and adhesion of the cured product, the content is preferably 10.0 parts by mass or less, more preferably 5.0 parts by mass or less, further preferably 3.0 parts by mass or less, further preferably 2.0 parts by mass or less, and particularly preferably 1.5 parts by mass or less.

[0098] <Component (E): Sulfide-based Curing Retardant> Component (E) is a hardening retarder having a thioether bond. Component (E) may be used alone or in combination of two or more.

[0099] Component (E) may be a chain sulfide or a cyclic sulfide. Examples of chain sulfides include diethyl sulfide, isobutyl sulfide, and dithioctanediol. Examples of cyclic sulfides include 1,3-dithiane, 1,3,5-trithiane, 1,4,7-trithiacyclononane, and 1,4,8,11-tetrathiacyclotetradecane.

[0100] <Component (F): Metal Complex Hardening Retardant> The component (F) may be a metal complex that functions as a hardening retarder. Examples of the component (F) include metal acetylacetonates. The components (F) may be used alone or in combination of two or more.

[0101] Examples of metal acetylacetonates include acetylacetonates of aluminum, titanium, zinc, zirconium, or copper. Among these, acetylacetonates of aluminum or zinc are preferred, and aluminum acetylacetonate is more preferred.

[0102] When the sealant of this embodiment includes component (F), the content of component (F) in the sealant of this embodiment is preferably 0.01 parts by mass or more, more preferably 0.02 parts by mass or more, relative to 100 parts by mass of component (A), from the viewpoint of obtaining a longer service life. From the viewpoint of further improving the performance balance between moisture resistance and adhesion of the cured product, the content is preferably 2.0 parts by mass or less, more preferably 1.0 part by mass or less.

[0103] <Component (G): Nitrogen oxide radical curing retarder> Component (G) is a hardening retarder having a nitroxide group. Component (G) may be used alone or in combination of two or more.

[0104] Examples of the component (G) include 2,2,6,6-tetramethyl-1-piperidinyl oxide (hereinafter referred to as TEMPO) or its derivatives such as 4-benzooxy-TEMPO, 4-methoxy-TEMPO, 4-carboxy-4-amino-TEMPO, 4-chloro-TEMPO, 4-hydroxyimino-TEMPO, 4-hydroxy-TEMPO, and 4-oxo-TEMPO; 4-amino-TEMPO, 2,2,5,5-tetramethyl-1-pyrrolidinyl oxide (hereinafter referred to as PROXYL) or its derivatives such as 3-carboxy-PROXYL, 3-aminoformyl-PROXYL, 2,2-dimethyl-4,5-cyclohexyl-PROXYL, and 3-oxo-PROXYL. XYL, 3-hydroxyimino-PROXYL, 3-aminomethyl-PROXYL, 3-methoxy-PROXYL, 3-tert-butyl-PROXYL, 3-maleimide-PROXYL, 3,4-di-tert-butyl-PROXYL, 3-carboxylic acid-2,2,5,5-tetramethyl-1-pyrrolidinyl oxide, etc.; dialkyl nitroxide free radical or its derivatives such as di-tert-butyl nitroxide, tert-butyl-tert-pentyl nitroxide, etc.; diaryl nitroxide free radical or its derivatives such as diphenyl nitroxide, etc.; 4,4-dimethyl-1-oxazolidinyl oxide (DOXYL) or its derivatives such as 2-di-tert-butyl-DOXYL, 5-decane-DOXYL, 2-cyclohexane-DOXYL, etc.; etc.

[0105] As the component (G), 2,2,6,6-tetramethyl-1-piperidinyl oxide is preferred.

[0106] When the sealant of this embodiment includes component (G), the content of component (G) in the sealant of this embodiment is preferably 0.01 parts by mass or more, more preferably 0.02 parts by mass or more, relative to 100 parts by mass of component (A), from the viewpoint of obtaining a longer service life. From the viewpoint of further improving the performance balance between moisture resistance and adhesion of the cured product, the content is preferably 2.0 parts by mass or less, more preferably 1.0 part by mass or less.

[0107] The sealant of this embodiment preferably contains components (C) and (D) as component (X). When the sealant of this embodiment contains components (C) and (D), the mass ratio of the content C1 of component (C) to the content D1 of component (D) (C1 / D1) is preferably 0.001 or greater, more preferably 0.005 or greater, further preferably 0.01 or greater, further preferably 0.05 or greater, particularly preferably 0.10 or greater, and further preferably 0.20 or greater, from the perspective of further improving the moisture resistance and adhesion of the cured product. From the perspective of further improving the moisture resistance and adhesion of the cured product, the mass ratio is preferably 2.0 or less, more preferably 1.0 or less, and further preferably 0.5 or less.

[0108] Regarding the total content of component (A), component (B) and component (X) in the sealant of this embodiment, when the total amount of the sealant of this embodiment is set to 100 mass%, from the viewpoint of further improving the coating property on the concave-convex substrate, it is preferably 60 mass% or more, more preferably 70 mass% or more, further preferably 80 mass% or more, further preferably 90 mass% or more, particularly preferably 95 mass% or more, further particularly preferably 98 mass% or more, and can be 100 mass% or less.

[0109] (Other ingredients) The sealant of this embodiment may further contain other components in addition to the component (A), the component (B), and the component (X).

[0110] Examples of other components include photosensitizers, silane coupling agents, antioxidants, inorganic fillers, resin particles, metal deactivators, fillers, stabilizers, neutralizers, lubricants, and antimicrobial agents.

[0111] The method for producing the sealant of this embodiment is not particularly limited, as long as the above-mentioned components can be thoroughly mixed. The mixing method of the components is not particularly limited, and examples include stirring methods utilizing the stirring force of a rotating propeller, and methods utilizing a conventional disperser such as a rotating planetary mixer. These mixing methods are preferred due to their low cost and stable mixing performance.

[0112] The method of using the sealant of this embodiment is not particularly limited. For example, by applying the sealant to an object (e.g., a component constituting a display device) and curing the sealant on the object, a hardened sealing layer containing a hardened body of the sealant can be formed.

[0113] Furthermore, the sealant of this embodiment can be cured into a predetermined shape (e.g., a film or sheet), thereby forming a hardened sealing layer having a predetermined shape. In this case, for example, when assembling a display device, the hardened sealing layer can be placed on a light-emitting diode element to seal the light-emitting diode element.

[0114] In this embodiment, the hardened sealing layer may be composed of a hardened sealant, or may include a hardened sealant and other constituent materials. Examples of other constituent materials include inorganic layers such as silicon nitride films, silicon oxide films, and silicon oxynitride; and inorganic fillers such as silicon dioxide, mica, kaolin, talc, and alumina.

[0115] According to the sealant of this embodiment, a display device including a light-emitting diode element and a hardened sealing layer can be easily manufactured.

[0116] To further enhance the sealant's coating properties on uneven substrates, the sealant of this embodiment preferably has a liquid specific gravity of 1.10 or greater, more preferably 1.12 or greater, even more preferably 1.15 or greater, and even more preferably 1.20 or greater, at 25°C. Furthermore, it is preferably 4.0 or less, more preferably 3.0 or less, even more preferably 2.5 or less, even more preferably 2.0 or less, and particularly preferably 1.5 or less. The liquid specific gravity of the sealant of this embodiment is measured using a 5 mL Gay-Lussac pycnometer in accordance with JIS-K-0061, Section 8.2.2. The types and amounts of the various components of the sealant of this embodiment can be appropriately adjusted to ensure that the liquid specific gravity falls within the above range.

[0117] To further enhance the sealant's coating properties on uneven substrates, the sealant of this embodiment preferably has a static surface tension of 50 mN / m or less, more preferably 40 mN / m or less, and even more preferably 35 mN / m or less, as measured by the pendant drop method. The lower limit of the static surface tension is not particularly limited; for example, it can be 10 mN / m or greater, 20 mN / m or greater, or even 25 mN / m or greater. The pendant drop method involves squeezing liquid from the tip of a tube and calculating the surface tension based on the shape of the resulting pendant drop.

[0118] 2. Hardened body The curing system of this embodiment is formed by curing the sealant of this embodiment. That is, by curing the sealant of this embodiment, a cured polymer containing the cationic polymerizable compound (A) can be obtained. The cured polymer of this embodiment can be preferably used as a cured sealing layer (especially a cured sealing layer for light-emitting diode devices).

[0119] The sealant of this embodiment, for example, increases in viscosity moderately after light irradiation and then hardens as the polymerization reaction of the cationic polymerizable compound (A) proceeds. The sealant after light irradiation can also be rapidly hardened by heating.

[0120] The light source for irradiating the sealant of this embodiment is not particularly limited. Examples thereof include halogen lamps, metal halide lamps, high-power metal halide lamps (containing indium, etc.), low-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, xenon lamps, xenon excimer lamps, xenon flash lamps, and LEDs. These light sources are preferred because they can efficiently irradiate with energy rays having a wavelength corresponding to the reaction wavelength of the cationic photopolymerization initiator.

[0121] Each of the above light sources has different radiation wavelengths or energy distributions. Therefore, the light source can be appropriately selected based on the reaction wavelength of the cationic photopolymerization initiator. Alternatively, natural light (sunlight) can also serve as a light source for initiating the sealant reaction.

[0122] Irradiation methods include direct irradiation, focused irradiation using a reflector, or focused irradiation using an optical fiber. Irradiation using a low-wavelength cutoff filter, a heat-ray cutoff filter, or a cold mirror is also possible.

[0123] The light irradiation dose is not particularly limited and can be appropriately adjusted according to the thickness of the sealant coating film, etc. The light irradiation dose can be, for example, 50 mJ / cm2 to 20,000 mJ / cm2, preferably 100 mJ / cm2 to 10,000 mJ / cm2.

[0124] When heating after light irradiation (also called post-heating) is performed, the heating temperature is preferably below 150° C., more preferably below 80° C., from the perspective of avoiding damage to light-emitting diode elements such as organic EL display elements.

[0125] 3. Display device The display device of this embodiment includes: a light-emitting diode element, a substrate, and a hardened sealing layer formed of the hardened body of this embodiment and located between the light-emitting diode element and the substrate.

[0126] The light emitting diode element includes, for example, an organic electroluminescent display element or a micro LED, preferably an organic electroluminescent display element. Furthermore, the light emitting diode element may be in the form of a substrate with a light emitting diode element (TFT substrate) as a concave-convex substrate.

[0127] The substrate is not particularly limited and may include, for example, one or more selected from the group consisting of a color filter, a glass substrate, a silicon substrate, and a plastic substrate. Preferably, the sealant comprises a color filter. The sealant of this embodiment has good coating properties on a concave-convex substrate. Therefore, when a color filter serving as a concave-convex substrate is used as the substrate, the effects of this embodiment can be more effectively achieved.

[0128] The manufacturing method of the display device of this embodiment may include, for example, a coating step of coating the sealant of this embodiment on a first member; an irradiation step of irradiating the coated sealant with light; and a bonding step of bonding the first member to the second member via the irradiated sealant. This manufacturing method allows the bonding surface of the first and second members constituting the display device to be sealed by curing the sealant layer. Examples of methods for applying the sealant of this embodiment to the first member include solution coating, spray coating, and other coating methods, flash evaporation, and inkjet methods. Among these, the inkjet method is preferred from the perspective of enhancing productivity. The thickness of the sealant applied to the first member is, for example, 1 μm to 15 μm, preferably 3 μm to 10 μm. Forming a film of 1 μm or greater and curing it facilitates achieving sufficient sealing capability as a hardened sealant layer. Furthermore, a film thickness of 15 μm or less contributes to miniaturization of display devices and reduced manufacturing costs.

[0129] The sealant applied to the first member during the coating step is tackified by light exposure. In the laminating step, the first and second members are bonded together before the light-exposed sealant hardens, thereby bonding the first and second members together via the sealant. The sealant between the first and second members is subsequently cured by heating, if necessary, to form a hardened sealant layer. Furthermore, the display device of this embodiment can also be manufactured by applying the sealant of this embodiment onto the first member, attaching the second member via the sealant, and then irradiating the sealant with light.

[0130] In the above manufacturing method, the steps after the irradiation step can also be performed in a light-shielding manner. In this way, the second component can be bonded to the first component without being exposed to light. The first component and the second component can each be a component constituting a display device, without particular limitation. In one aspect, the first component can be a light-emitting diode (LED) and the second component can be a substrate. In another aspect, the first component can be a substrate and the second component can be a LED. Specifically, one of the first and second components can be a substrate and the other a LED.

[0131] 4. Solar cells The solar cell of this embodiment comprises: a solar cell, a substrate, and a hardened sealing layer comprising the hardened body of this embodiment located between the solar cell and the substrate. The solar cell of this embodiment preferably comprises a perovskite solar cell.

[0132] 5. Composition The composition of the present embodiment comprises a cationically polymerizable compound (A), a cationic polymerization initiator (B), and a curing retarder (X). In a viscosity measurement conducted under the following measurement condition 1, the viscosity 20 seconds after the start of the measurement is defined as V0. 30 seconds after the start of the measurement, the composition is irradiated perpendicularly with ultraviolet light having a wavelength of 365 nm and a power of 30 mW / cm2 (a total of 600 mJ / cm2) for 20 seconds from a position 15 cm from the start of the measurement toward the alkali-free glass plate. 60 seconds after the end of the ultraviolet irradiation is defined as V1. The viscosity change rate represented by V1 / V0 is 1.00 or greater and less than 1.75.

[0133] <Measurement Condition 1> Device: Rheometer (viscoelasticity measuring device) Temperature: 25℃ Geometry (jig) (upper side): 8 mm diameter ,Aluminum parallel plates Plate (bottom): diameter 38 mm , alkali-free glass plate Shear speed: 1 min -1 Pitch: 0.05 mm Sample size: 20 mg Atmosphere: Nitrogen flow

[0134] According to the composition of this embodiment, by keeping the viscosity change rate represented by V1 / V0 within the above range, coating properties on concave-convex substrates such as color filters or substrates with light-emitting diodes (TFT substrates) can be improved. The sealant of this embodiment can be easily spread on concave-convex substrates without uneven coating, thus suppressing the presence of bubbles in the coating film. As a result, a cured layer with improved transparency can be formed on the concave-convex substrate.

[0135] The composition of this embodiment is controlled so that the viscosity change ratio, represented by V1 / V0, is greater than 1.00 and less than 1.75. This improves the coating properties of the composition of this embodiment on uneven substrates. The reason for this is not yet clear, but the following are considered. First, it is believed that by keeping the viscosity change rate represented by V1 / V0 above the lower limit, it is possible to suppress uneven film thickness caused by excessive wetting and spreading of the applied droplet. Furthermore, it is believed that by keeping the viscosity change rate represented by V1 / V0 below the upper limit, wetting and spreading are facilitated on the uneven surface of the substrate, thereby suppressing the presence of bubbles in the coated film and uneven film thickness. Here, in order to adjust the viscosity change rate represented by V1 / V0 within the above range, it is important to, for example, appropriately select the types of the cationic polymerizable compound (A), cationic polymerization initiator (B), and hardening retarder (X) constituting the composition of this embodiment and appropriately adjust the content ratio of each component; after mixing the components, add molecular sieves, let stand for dehydration, and then filter; and manufacture under a "yellow light environment" with a short wavelength cutoff of 500 nm or less (500 nm or less) to suppress unintended polymerization.

[0136] The preferred aspects and preferred contents of the components constituting the composition of this embodiment, as well as the preferred physical properties and characteristics of the composition of this embodiment can be selected in the same manner as the sealant of this embodiment, and therefore, description thereof is omitted here. The composition of the present embodiment can be produced by the same production method as that of the sealant of the present embodiment. The composition of this embodiment can be used as, for example, a sealant, an adhesive, a photosensitive resin layer, an insulating resin layer, a thermally conductive resin layer, a covering material, and the like.

[0137] While the embodiments of the present invention have been described above, these are merely illustrative examples of the present invention, and various configurations other than those described above may be employed. Furthermore, the present invention is not limited to the aforementioned embodiments; modifications and improvements within the scope of achieving the objectives of the present invention are encompassed by the present invention. [Example]

[0138] The present invention will be described in more detail below with reference to the following examples, but the present invention is not limited to these examples. Unless otherwise specified, the examples were tested at 23° C. and a relative humidity of 50% by mass.

[0139] (Examples 1-4, Comparative Examples 1-2) <Preparation of sealant> The sealants of Examples and Comparative Examples were prepared by mixing the components listed in Table 1 at the composition ratios (parts by mass) under a short-wavelength yellow light environment with a cutoff wavelength of 500 nm or less. The mixture was then allowed to stand for dehydration using molecular sieves (5A granular, manufactured by Union Showa) and then filtered. The resulting sealant was tested for various viscosity, liquid specific gravity, and static surface tension using the evaluation methods described below. The sealant's coating properties were also evaluated using the evaluation methods described below. Furthermore, the sealant was cured under the light curing conditions described below to form a cured product, and its transparency was evaluated using the evaluation methods described below. The evaluation results are shown in Table 1.

[0140] The meanings of the components shown in Table 1 are as follows.

[0141] (Component (A1): an alicyclic compound having an epoxy group) (a1-1) 3',4'-Epoxycyclohexylmethyl 3,4-epoxycyclohexylcarboxylate ("Celloxide 2021P" manufactured by Daicel Chemical Co., Ltd.) (a1-2) (3,3',4,4'-diepoxy)bicyclohexane ("Celloxide 8010" manufactured by Daicel Chemical Co., Ltd.)

[0142] (Component (A2): Aromatic compound having an epoxy group) (a2-1) Bisphenol A epoxy resin (molecular weight 360-390, "jER828" manufactured by Mitsubishi Chemical Corporation) (a2-2) Bisphenol F epoxy resin (molecular weight 320-340, "jER806" manufactured by Mitsubishi Chemical Corporation) (a2-3) Dibromophenyl glycidyl ether ("BR-250H" manufactured by Nippon Kayaku Co., Ltd., molecular weight 308)

[0143] (Component (A3): glycidyl ether compound) (a3-1) 1,6-Hexanediol diglycidyl ether ("ED-503G" manufactured by ADEKA) (a3-2) Neopentyl glycol diglycidyl ether ("Denacol EX-211" manufactured by Nagase Chemicals Co., Ltd.)

[0144] (Component (B): cationic photopolymerization initiator) (b-1) Triaryl iron salt hexafluoroantimonate ("Adeka Optomer SP-170" manufactured by ADEKA, the anion species is hexafluoroantimonate) (b-2) Triarylsulfonium tetrakis-pentafluorophenyl gallate ("CPI-310FG" manufactured by San-Apro)

[0145] (Component (C): Phosphate-based hardening retarder) (c-1) Tri(2-ethylhexyl) phosphate ("TOP" manufactured by Daihachi Chemical Industry Co., Ltd.)

[0146] (Component (D): ether-based curing retarder) (d-1) 18-crown-6-ether ("Crown Ether O-18" manufactured by Tokyo Chemical Industry Co., Ltd.)

[0147] [Viscosity measurement method] The viscosity of the sealants of Examples and Comparative Examples was measured using the following measurement conditions 1. The viscosity 20 seconds after the start of the viscosity measurement was defined as V0. 30 seconds after the start of the measurement, the non-alkali glass plate was irradiated with ultraviolet light at a wavelength of 365 nm and 30 mW / cm² (a total of 600 mJ / cm²) perpendicularly toward the plate for 20 seconds from a distance of 15 cm from the plate. The viscosity 60 seconds after the end of the ultraviolet irradiation was defined as V1, and the viscosity 10 minutes after the end of the ultraviolet irradiation was defined as V2. Ultraviolet irradiation was performed while continuously measuring viscosity using an ultraviolet irradiation device attached to the rheometer (Execure 3000, manufactured by HOYA Corporation). "Start of measurement" refers to the moment the sample is placed in the device and begins rotating. <Measurement Condition 1> Apparatus: Rheometer (manufactured by Anton Paar, product name "MCR301") Temperature: 25℃ Geometry (top side): 8 mm diameter ,Aluminum parallel plates Plate (bottom): diameter 38 mm , alkali-free glass plate Shear speed: 1 min -1 Pitch: 0.05 mm Sample size: 20 mg Atmosphere: Nitrogen flow (1000 mL / min)

[0148] [Liquid specific gravity] The liquid specific gravity of the sealants of Examples and Comparative Examples was measured using a 5 mL Gay-Lussac pycnometer in accordance with 8.2.2 of JIS-K-0061.

[0149] [Static surface tension] The static surface tension of the sealants of Examples and Comparative Examples was measured by the pendant drop method using a contact angle meter (DM500 manufactured by Kyowa Interface Science Co., Ltd.) in an atmosphere at 23°C.

[0150] [Evaluation of coating properties] A 10 μL drop of sealant was placed on a 25 mm square color filter. The filter was then irradiated with 600 mJ / cm² of ultraviolet light using a high-pressure mercury lamp. After 10 minutes, the filter was bonded to an alkali-free glass plate and a 1 kg weight was placed on the plate. The sealant was then spread over the filter using image processing software. The coating properties were evaluated according to the following criteria. A (very good): The sealant is spread over an area of ​​625 mm2 B (good): The area of ​​sealant spread is more than 300 mm2 and less than 625 mm2 C (bad): The sealant spread area does not reach 300 mm2

[0151] [Evaluation of transparency] A sealant was applied evenly to a 50 mm square color filter, totaling 0.024 g. The film was then irradiated with UV light at 600 mJ / cm² using a high-pressure mercury lamp. After 10 minutes, the film was bonded to an alkali-free glass plate and vacuum-pressed at 0.05 kN. After pressurization, the presence of bubbles between the droplets was checked. Transparency was evaluated based on the following criteria. A (very good): no bubbles B (good): with bubbles C (bad): The droplets do not touch each other and exist in a circular shape at the coating location.

[0152] [Table 1] Table 1 Ingredients Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Cationic polymerizable compound (A) (a1-1) 70 68 58 20 70 (a1-2) 70 (a2-1) 15 (a2-2) 5 15 15 (a2-3) 28 25 25 30 (a3-1) 2 2 2 (a3-2) 80 Cationic polymerization initiator (B) (b-1) 0.5 (b-2) 0.25 0.25 0.25 0.5 0.25 Phosphate-based hardening retarder (C) (c-1) 0.3 0.3 0.3 0.01 0.3 Ether-based hardening retarder (D) (d-1) 1 1 1 1 1 1 V 0 [mPa·s] 200 220 260 12 400 70 V 1 [mPa·s] 200 340 450 12 700 230 V 1 / V 0 [-] 1.00 1.55 1.73 1.00 1.75 3.29 V 2 [mPa·s] 400 830 1500 30 5,000 1700 Liquid specific gravity [-] 1.23 1.21 1.21 1.13 1.19 1.25 Static surface tension [mN / m] 33 34 36 33 39 33 Coating properties A A B A C C Transparency A A B A C C

[0153] This application claims priority based on Japanese Patent Application No. 2022-177417, filed on November 4, 2022, and all contents disclosed therein are incorporated into this case.

Claims

1. A sealant comprising a cationic polymerizable compound (A), a cationic polymerization initiator (B), and a curing retarder (X), wherein, in a viscosity determination performed under the following determination conditions 1, the viscosity 20 seconds after the start of the determination is set as V0, and after 30 seconds after the start of the determination, ultraviolet light with a wavelength of 365 nm and a concentration of 30 mW / cm² (total 600 mJ / cm²) is irradiated perpendicularly towards the alkali-free glass plate from a distance of 15 cm towards the alkali-free glass plate for 20 seconds, and the viscosity 60 seconds after the end of the ultraviolet irradiation is set as V1, the viscosity change rate expressed by V1 / V0 is 1.00 or higher and less than 1.

75. <Determination Conditions 1> Apparatus: Rheometer Temperature: 25°C Geometry (top): Diameter 8 mm, Aluminum parallel plate (bottom): Diameter 38 mm, Alkali-free glass plate shear rate: 1 min⁻¹ Spacing: 0.05 mm Sample amount: 20 mg Atmosphere: Nitrogen gas flow.

2. The sealant of claim 1, wherein the viscosity V0 is above 1 mPa·s and below 1000 mPa·s.

3. The sealant as requested in item 1 or 2, wherein the viscosity V1 is above 1 mPa·s and below 2000 mPa·s.

4. The sealant of claim 1 or 2, wherein the aforementioned cationic polymeric compound (A) contains an epoxy group.

5. The sealant of claim 4, wherein the aforementioned cationic polymeric compound (A) comprises one or more of the group consisting of an alicyclic compound having an epoxy group (A-1), an aromatic compound having an epoxy group (A-2), and a glycidyl ether compound (A-3).

6. The sealant of claim 1 or 2, wherein the aforementioned cationic polymeric compound (A) contains bromine atoms.

7. The sealant of claim 1 or 2, in the viscosity test conducted by means of the above-described test conditions 1, has a viscosity V2 of 5000 mPa·s or less 10 minutes after the end of the above-described ultraviolet irradiation.

8. The sealant of request item 1 or 2 has a liquid specific gravity of 1.10 or higher in an atmosphere at 25°C.

9. The sealant of claim 1 or 2 has a static surface tension of less than 50 mN / m obtained by the pendant drop method.

10. The sealant of claim 1 or 2, wherein the cationic polymerization initiator (B) comprises one or more selected from the group consisting of cationic photopolymerization initiator (B1) and cationic thermal polymerization initiator (B2).

11. The sealant of claim 10, wherein the aforementioned cationic polymerization initiator (B) comprises an onium salt compound.

12. The sealant of claim 1 or 2, wherein the content of the above-mentioned cationic polymerization initiator (B) is more than 0.01 parts by mass and less than 5.0 parts by mass relative to 100 parts by mass of the above-mentioned cationic polymerizable compound (A).

13. The sealant of claim 1 or 2, wherein the curing retardant (X) comprises one or more of the group consisting of phosphoric acid curing retardants, ether curing retardants, thioether curing retardants, metal complex curing retardants, and nitroxide radical curing retardants.

14. The sealant of claim 1 or 2, wherein the content of the curing delay agent (X) is 0.10 parts by mass to 10.0 parts by mass relative to 100 parts by mass of the cationic polymeric compound (A).

15. The sealant as requested in item 1 or 2, which is used in light-emitting diode elements.

16. The sealant as claimed in item 1 or 2, used for bonding color filters to organic electroluminescent display elements or for bonding color filters to micro LEDs.

17. The sealant as requested in item 1 or 2, which can be used to seal solar cell cells.

18. The sealant of claim 17, wherein the solar cell comprises a perovskite solar cell.

19. A hardened body formed by hardening a sealant as claimed in any one of claims 1 to 18.

20. A display device comprising: a light-emitting diode element, a substrate, and a hardened sealing layer formed of a hardened body as claimed in claim 19 located between the light-emitting diode element and the substrate.

21. The display device of claim 20, wherein the light-emitting diode element comprises an organic electroluminescent display element or a micro LED.

22. The display device of claim 20 or 21, wherein the substrate comprises a color filter.

23. A method for manufacturing a display device, comprising: The coating step involves applying a sealant, such as any one of claims 1 to 16, onto the first component; the irradiation step involves irradiating the applied sealant with light; and the bonding step involves bonding the first component and the second component together via the light-irradiated sealant.

24. A method for manufacturing a display device as claimed in claim 23, wherein one of the first component and the second component is a substrate and the other is a light-emitting diode element.

25. A method for manufacturing a display device as claimed in claim 24, wherein the light-emitting diode element comprises an organic electroluminescent display element or a micro LED.

26. A method for manufacturing a display device as claimed in claim 24 or 25, wherein the substrate comprises a color filter.

27. A solar cell comprising: a solar cell cell, a substrate, and a hardened sealing layer comprising a hardened body as claimed in claim 19, located between the solar cell cell and the substrate.

28. The solar cell of claim 27, wherein the solar cell comprises a perovskite solar cell.

29. A composition comprising a cationic polymerizable compound (A), a cationic polymerization initiator (B), and a curing retarder (X), wherein, in a viscosity determination performed under the following determination conditions 1, the viscosity 20 seconds after the start of the determination is defined as V0, and after 30 seconds after the start of the determination, ultraviolet light (at a wavelength of 365 nm and a concentration of 30 mW / cm², totaling 600 mJ / cm²) is irradiated perpendicularly towards the alkali-free glass plate from a distance of 15 cm towards the alkali-free glass plate for 20 seconds, and the viscosity 60 seconds after the end of the ultraviolet irradiation is defined as V1, the viscosity change rate expressed by V1 / V0 is 1.00 or more and less than 1.

75. <Determination Conditions 1> Apparatus: Rheometer Temperature: 25°C Geometry (top): Diameter 8 mm, Aluminum parallel plate (bottom): Diameter 38 mm, Alkali-free glass plate shear rate: 1 min⁻¹ Spacing: 0.05 mm Sample amount: 20 mg Atmosphere: Nitrogen gas flow.