Sealant for dimming elements

Abstract

The present invention aims to provide a sealant for dimming elements that can be cured by light irradiation to produce a product with excellent water penetration resistance and conformability to deformation of the substrate. Furthermore, the present invention aims to provide a method for using a curable resin composition as a sealant for dimming elements. The present invention relates to a sealant for a dimming element used to seal a dimming element having a dimming material, comprising a curable resin and a photoradical polymerization initiator, wherein the curable resin comprises a (meth)acrylic compound, and the (meth)acrylic compound comprises a compound having one (meth)acryloyl group, one or more aromatic rings, and one or more hydroxyl groups or carboxyl groups in one molecule.

Description

Technical Field

[0001] The present invention relates to a sealing agent for a dimming element. The present invention also relates to the use of a curable resin composition as the sealing agent for the dimming element.

Background Art

[0002] Dimming elements that change the light transmittance by applying a voltage are used in a wide range of applications. For example, in buildings and automobiles, laminated glass including dimming elements is used. In such laminated glass, a dimming element in which a dimming material is sandwiched between films with transparent electrodes is sandwiched between an intermediate film and a pair of glasses. In addition, in dimming elements, a sealing agent is usually used to protect the dimming material from moisture, contaminants, and the like. For example, Patent Document 1 discloses that a sealing portion using a curable resin is provided by coating formation at the peripheral edge of a dimming film in order to protect a liquid crystal layer from moisture, acid, ultraviolet rays, and the like.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Conventionally, sealants used for dimming elements have been those that excel in preventing moisture intrusion into dimming materials (moisture resistance). However, sealants with excellent moisture resistance sometimes cannot follow the deformation of films or glass. For example, when laminated glass is exposed to a high-temperature, high-humidity environment for a long time, the sealant may peel off when the substrate such as film or glass warps. On the other hand, if the flexibility of the sealant is improved to give it excellent conformability to the deformation of the substrate, it may not be able to adequately prevent moisture intrusion. Furthermore, from the viewpoint of shortening the work process, there has been a need for a sealant that can be cured by light irradiation to obtain a product with sufficient moisture resistance and conformability.

[0005] The present invention aims to provide a sealant for dimming elements that can be cured by light irradiation to produce a product with excellent water penetration resistance and conformability to deformation of the substrate. Furthermore, the present invention aims to provide a method for using a curable resin composition as a sealant for dimming elements. [Means for solving the problem]

[0006] Disclosure 1 is a sealant for a dimming element used to seal a dimming element having a dimming material, comprising a curable resin and a photoradical polymerization initiator, wherein the curable resin comprises a (meth)acrylic compound, and the (meth)acrylic compound comprises a compound having one (meth)acryloyl group, one or more aromatic rings, and one or more hydroxyl groups or carboxyl groups in one molecule. Disclosure 2 is a sealant for a dimming element according to Disclosure 1, wherein the (meth)acrylic compound is selected from the group consisting of a compound having one (meth)acryloyl group and one or more structures represented by the following formula (1) in one molecule, and a compound having one (meth)acryloyl group and one or more structures represented by the following formula (2) in one molecule. Disclosure 3 relates to the above-mentioned sealant for dimming element with an illuminance of 100 mW / cm². 2This is a sealant for a dimming element according to disclosure 1 or 2, wherein the glass transition temperature of the cured product obtained by irradiating it with light for 30 seconds is 60.0°C or higher and less than 85.0°C. Disclosure 4 is a sealant for a dimming element of Disclosure 1, 2, or 3, wherein the dimming material is a PDLC. Disclosure 5 relates to the use of a curable resin composition containing a curable resin and a photoradical polymerization initiator, wherein the curable resin contains a (meth)acrylic compound, and the (meth)acrylic compound contains a compound having one (meth)acryloyl group, one or more aromatic rings, and one or more hydroxyl groups or carboxyl groups in one molecule, as a sealant for a dimming element.

[0007] [ka]

[0008] In equation (1), * represents the bond position.

[0009] [ka]

[0010] In equation (2), * represents the bond position.

[0011] The present invention will be described in detail below. The inventors of the present invention have found that, regarding a sealant for a dimming element containing a curable resin and a photoradical polymerization initiator, by using a (meth)acrylic compound having a specific structure as the curable resin, a cured product with excellent water penetration resistance and conformability to deformation of the substrate can be obtained by light irradiation, and have completed the present invention.

[0012] The sealant for dimming elements of the present invention contains a curable resin. The above-mentioned curable resin contains a (meth)acrylic compound. By including the above-mentioned (meth)acrylic compound as the curable resin, the sealant for dimming elements of the present invention is less likely to cause contamination of dimming materials (excellent low-contamination properties). In this specification, "(meth)acrylic" means acrylic or methacrylic, "(meth)acrylic compound" means a compound having a (meth)acryloyl group, and "(meth)acryloyl" means acryloyl or methacryloyl.

[0013] The above (meth)acrylic compound includes a compound having one (meth)acryloyl group, one or more aromatic rings, and one or more hydroxyl or carboxyl groups in one molecule (hereinafter also referred to as "the monofunctional (meth)acrylic compound according to the present invention"). By containing the monofunctional (meth)acrylic compound according to the present invention, the sealant for dimming elements of the present invention can produce a cured product with excellent water penetration resistance and conformability to deformation of the substrate.

[0014] There is no particular preferred upper limit to the number of aromatic rings that the monofunctional (meth)acrylic compound according to the present invention may have in one molecule, but the practical upper limit is 3. The number of aromatic rings is counted as follows: for example, one for a benzene ring, two for a naphthalene ring, and three for an anthracene ring.

[0015] There is no particular preferred upper limit to the number of hydroxyl groups or carboxyl groups that the monofunctional (meth)acrylic compound according to the present invention may have in one molecule, but the substantial upper limit is 2. Furthermore, the monofunctional (meth)acrylic compound according to the present invention may have both hydroxyl groups and carboxyl groups. In this case, the number of hydroxyl groups or carboxyl groups in one molecule of the monofunctional (meth)acrylic compound according to the present invention means the sum of the number of hydroxyl groups and the number of carboxyl groups. Moreover, the above (meth)acrylic compound may include, as the monofunctional (meth)acrylic compound according to the present invention, a compound having one (meth)acryloyl group, one or more aromatic rings, and one or more hydroxyl groups in one molecule, and a compound having one (meth)acryloyl group, one or more aromatic rings, and one or more carboxyl groups in one molecule, in combination.

[0016] The above (meth)acrylic compound preferably contains at least one selected from the group consisting of a compound having one (meth)acryloyl group and one or more structures represented by the above formula (1) in one molecule, and a compound having one (meth)acryloyl group and one or more structures represented by the above formula (2) in one molecule, as the monofunctional (meth)acrylic compound according to the present invention.

[0017] Specific examples of the monofunctional (meth)acrylic compound according to the present invention include, for example, 2-hydroxy-3-phenoxypropyl (meth)acrylate, phthalic acid monohydroxyethyl (meth)acrylate, 2-acryloyloxyethyl-2-hydroxyethyl-phthalic acid, and the like. Among them, 2-hydroxy-3-phenoxypropyl (meth)acrylate is preferable as the compound having one (meth)acryloyl group and one or more structures represented by the above formula (1) in one molecule, and phthalic acid monohydroxyethyl (meth)acrylate is preferable as the compound having one (meth)acryloyl group and one or more structures represented by the above formula (2) in one molecule. In the present specification, the above "(meth)acrylate" means acrylate or methacrylate.

[0018] The preferable lower limit of the content of the monofunctional (meth)acrylic compound according to the present invention in 100 parts by mass of the above curable resin is 16 parts by mass, and the preferable upper limit is 50 parts by mass. When the content of the monofunctional (meth)acrylic compound according to the present invention is 16 parts by mass or more, a cured product excellent in water intrusion resistance and followability to deformation of the base material can be obtained for the obtained light control element sealing agent. When the content of the monofunctional (meth)acrylic compound according to the present invention is 50 parts by mass or less, the obtained light control element sealing agent is excellent in curability and adhesiveness. The more preferable lower limit of the content of the monofunctional (meth)acrylic compound according to the present invention is 25 parts by mass, and the more preferable upper limit is 33 parts by mass. The content of the monofunctional (meth)acrylic compound according to the present invention in 100 parts by mass of the above curable resin may be 16 parts by mass or more and 50 parts by mass or less, or may be 25 parts by mass or more and 33 parts by mass or less.

[0019] The above (meth)acrylic compound preferably further contains a compound having two or more (meth)acryloyl groups in one molecule (hereinafter also referred to as "a (meth)acrylic compound having two or more functional groups"). By containing the above (meth)acrylic compound having two or more functional groups as the above (meth)acrylic compound, the sealant for the dimming element of the present invention becomes excellent in curability and adhesiveness.

[0020] Examples of the above (meth)acrylic compound having two or more functional groups include those having two or more (meth)acryloyl groups in one molecule, such as epoxy (meth)acrylate, (meth)acrylate compound, urethane (meth)acrylate, etc. Among them, from the viewpoint of low contamination (especially low liquid crystal contamination), the above (meth)acrylic compound having two or more functional groups preferably contains epoxy (meth)acrylate. In the present specification, the above "epoxy (meth)acrylate" means a compound obtained by reacting all epoxy groups in an epoxy compound with (meth)acrylic acid.

[0021] Examples of the above epoxy (meth)acrylate include those obtained by reacting an epoxy compound having two or more epoxy groups in one molecule with (meth)acrylic acid according to a conventional method in the presence of a basic catalyst.

[0022] Examples of epoxy compounds that serve as raw materials for the above-mentioned epoxy (meth)acrylate include bisphenol A type epoxy compounds, bisphenol F type epoxy compounds, bisphenol E type epoxy compounds, bisphenol S type epoxy compounds, 2,2'-diallylbisphenol A type epoxy compounds, hydrogenated bisphenol type epoxy compounds, propylene oxide-added bisphenol A type epoxy compounds, resorcinol type epoxy compounds, biphenyl type epoxy compounds, sulfide type epoxy compounds, diphenyl ether type epoxy compounds, dicyclopentadiene type epoxy compounds, naphthalene type epoxy compounds, phenol novolac type epoxy compounds, orthocresol novolac type epoxy compounds, dicyclopentadiene novolac type epoxy compounds, biphenyl novolac type epoxy compounds, naphthalene phenol novolac type epoxy compounds, glycidylamine type epoxy compounds, alkyl polyol type epoxy compounds, rubber-modified epoxy compounds, glycidyl ester compounds, and the like.

[0023] Examples of the difunctional (meth)acrylic acid ester compounds listed above include 1,3-butanediol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, 2-n-butyl-2-ethyl-1,3-propanediol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, and polypropylene glycol di Examples include (meth)acrylate, neopentyl glycol di(meth)acrylate, ethylene oxide-added bisphenol A di(meth)acrylate, propylene oxide-added bisphenol A di(meth)acrylate, ethylene oxide-added bisphenol F di(meth)acrylate, dimethylol dicyclopentadienyl di(meth)acrylate, ethylene oxide-modified isocyanurate di(meth)acrylate, 2-hydroxy-3-(meth)acryloyloxypropyl(meth)acrylate, carbonate diol di(meth)acrylate, polyether diol di(meth)acrylate, polyester diol di(meth)acrylate, polycaprolactone diol di(meth)acrylate, polybutadiene diol di(meth)acrylate, and the like.

[0024] Examples of the above (meth)acrylic acid ester compounds that have three or more functionalities include ethylene oxide-added isocyanuric acid tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, ethylene oxide-added trimethylolpropane tri(meth)acrylate, propylene oxide-added trimethylolpropane tri(meth)acrylate, caprolactone-modified trimethylolpropane tri(meth)acrylate, glycerin tri(meth)acrylate, propylene oxide-added glycerin tri(meth)acrylate, pentaerythritol tri(meth)acrylate, tris(meth)acryloyloxyethyl phosphate, ditrimethylolpropane tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, and dipentaerythritol hexa(meth)acrylate.

[0025] The above-mentioned urethane (meth)acrylate can be obtained, for example, by reacting an isocyanate compound with a (meth)acrylic acid derivative having a hydroxyl group in the presence of a catalytic amount of a tin-based compound.

[0026] Examples of isocyanate compounds that serve as raw materials for the above-mentioned urethane (meth)acrylate include isophorone diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, diphenylmethane-4,4'-diisocyanate (MDI), hydrogenated MDI, polymeric MDI, 1,5-naphthalene diisocyanate, norbornane diisocyanate, tollidine diisocyanate, xylylene diisocyanate (XDI), hydrogenated XDI, lysine diisocyanate, triphenylmethane triisocyanate, tris(isocyanatephenyl)thiophosphate, tetramethylxylylene diisocyanate, and 1,6,11-undecane triisocyanate.

[0027] Furthermore, as the isocyanate compound used as a raw material for the above-mentioned urethane (meth)acrylate, a chain-extended isocyanate compound obtained by the reaction of a polyol with an excess isocyanate compound can also be used. Examples of the polyols mentioned above include ethylene glycol, propylene glycol, glycerin, sorbitol, trimethylolpropane, carbonate diol, polyether diol, polyester diol, and polycaprolactone diol.

[0028] Examples of (meth)acrylic acid derivatives having the hydroxyl group mentioned above include hydroxyalkyl (meth)acrylates, mono(meth)acrylates of dihydric alcohols, mono(meth)acrylates or di(meth)acrylates of trihydric alcohols, epoxy (meth)acrylates, and the like. Examples of the hydroxyalkyl (meth)acrylates mentioned above include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate. Examples of the dihydric alcohols mentioned above include ethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, polyethylene glycol, and the like. Examples of the above-mentioned trivalent alcohols include trimethylolethane, trimethylolpropane, and glycerin. Examples of the epoxy (meth)acrylates mentioned above include bisphenol A type epoxy (meth)acrylate.

[0029] The preferred lower limit for the content of the (meth)acrylic compound in 100 parts by mass of the curable resin is 50 parts by mass. A content of 50 parts by mass or more of the (meth)acrylic compound results in a sealant for dimming elements that exhibits superior low contamination (particularly low liquid crystal contamination). A more preferred lower limit for the content of the (meth)acrylic compound is 66 parts by mass. Furthermore, a cured product with superior low tack properties can be obtained solely by light irradiation, and superior high-temperature water resistance and water penetration resistance can be achieved. Therefore, it is particularly preferable that the content of the (meth)acrylic compound in 100 parts by mass of the curable resin is 100 parts by mass, i.e., that the curable resin is composed solely of the (meth)acrylic compound. Additionally, increasing the content of the (meth)acrylic compound in 100 parts by mass of the curable resin results in a sealant for dimming elements that also exhibits superior effectiveness in preventing the penetration of plasticizers and solvents.

[0030] If the above-mentioned curable resin contains other curable resins besides the (meth)acrylic compound, examples of such other curable resins include epoxy compounds. Examples of epoxy compounds used as other curable resins include those described above as epoxy compounds that serve as raw materials for epoxy (meth)acrylate.

[0031] The preferred lower limit of the total content of the curable resin in 100 parts by mass of the sealant for dimming elements of the present invention is 66 parts by mass, and the preferred upper limit is 99 parts by mass. Having the total content of the curable resin within this range results in a sealant for dimming elements with superior curability and adhesion.

[0032] The sealant for dimming elements of the present invention contains a photoradical polymerization initiator that generates radicals upon light irradiation. By combining the above-mentioned photoradical polymerization initiator with the above-mentioned curable resin containing a monofunctional (meth)acrylic compound according to the present invention, the sealant for dimming elements of the present invention can produce a cured product with excellent water penetration resistance and conformability to deformation of the substrate upon light irradiation.

[0033] Examples of the above-mentioned photoradical polymerization initiators include benzophenone compounds, acetophenone compounds, acylphosphine oxide compounds, titanocene compounds, oxime ester compounds, benzoin ether compounds, and thioxanthone compounds. Examples of the above-mentioned photoradical polymerization initiators include, specifically, 1-hydroxycyclohexylphenyl ketone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone, 2-(dimethylamino)-2-((4-methylphenyl)methyl)-1-(4-(4-morpholinyl)phenyl)-1-butanone, 2,2-dimethoxy-1,2-diphenylethane-1-one, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, and 2-methyl-1-(4-methylthiophenyl). Examples include -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, and 2,4-dimethylthioxanthene-9-one.

[0034] The preferred lower limit of the content of the above-mentioned photoradical polymerization initiator is 0.01 parts by mass and the preferred upper limit is 10 parts by mass per 100 parts by mass of the above-mentioned curable resin. Having the radical polymerization initiator content within this range results in a sealant for dimming elements having superior storage stability and photocurability. A more preferred lower limit for the radical polymerization initiator content is 0.1 parts by mass and a more preferred upper limit is 5 parts by mass. The amount of the photoradical polymerization initiator per 100 parts by mass of the curable resin may be 0.01 parts by mass or more and 10 parts by mass or less, or 0.1 parts by mass or more and 5 parts by mass or less.

[0035] The sealing agent for dimming elements of the present invention may also contain, in addition to the above-mentioned photoradical polymerization initiator, a thermal radical polymerization initiator that generates radicals upon heating.

[0036] Examples of the above-mentioned thermal radical polymerization initiators include those composed of azo compounds and organic peroxides. Among these, initiators composed of azo compounds (hereinafter also referred to as "azo initiators") are preferred from the viewpoint of suppressing contamination of light-adjusting materials.

[0037] Examples of the above-mentioned azo compounds include those having a structure in which multiple units such as polyalkylene oxides and polydimethylsiloxanes are bonded via an azo group, polycondensates of 2,2'-azobis(2,4-dimethylvaleronitrile), 4,4'-azobis(4-cyanovaleric acid), 4,4'-azobis(4-cyanopentanoic acid) and polyalkylene glycols, and polycondensates of 4,4'-azobis(4-cyanopentanoic acid) and polydimethylsiloxanes having terminal amino groups. Examples of the above-mentioned azo initiators include VPE-0201, VPE-0401, VPE-0601, VPS-0501, VPS-1001, V-65, and V-501 (all manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.).

[0038] Examples of the above-mentioned organic peroxides include ketone peroxides, peroxyketals, hydroperoxides, dialkyl peroxides, peroxyesters, diacyl peroxides, and peroxydicarbonates.

[0039] The preferred lower limit of the content of the above-mentioned thermal radical polymerization initiator is 0.01 parts by mass and the preferred upper limit is 10 parts by mass per 100 parts by mass of the above-mentioned curable resin. Having the content of the above-mentioned thermal radical polymerization initiator within this range results in a sealant for dimming elements having superior storage stability and thermosetting properties. A more preferred lower limit for the content of the above-mentioned thermal radical polymerization initiator is 0.1 parts by mass, a more preferred upper limit is 5 parts by mass, and an even more preferred upper limit is 0.2 parts by mass. The content of the thermal radical polymerization initiator per 100 parts by mass of the curable resin may be 0.01 parts by mass or more and 10 parts by mass or less, 0.1 parts by mass or more and 5 parts by mass or less, or 0.1 parts by mass or more and 0.2 parts by mass or less.

[0040] The sealant for dimming elements of the present invention may contain a thermosetting agent. In particular, when the curable resin includes an epoxy compound as another curable resin, the sealant for dimming elements of the present invention preferably contains a thermosetting agent.

[0041] Examples of the above-mentioned thermosetting agents include organic acid hydrazides, imidazole derivatives, amine compounds, polyhydric phenolic compounds, and acid anhydrides. Among these, organic acid hydrazides are preferably used.

[0042] Examples of the above-mentioned organic acid hydrazides include sebacate dihydrazide, isophthalic acid dihydrazide, adipic acid dihydrazide, and malonic acid dihydrazide.

[0043] The content of the above-mentioned thermosetting agent is preferably 1 part by mass and preferably 50 parts by mass per 100 parts by mass of the above-mentioned curable resin. By having the content of the above-mentioned thermosetting agent within this range, the resulting sealant for the dimming element can be made more thermosetting without degrading its applicability. A more preferable upper limit for the content of the above-mentioned thermosetting agent is 30 parts by mass.

[0044] The sealant for dimming elements of the present invention may further contain, if necessary, additives such as a curing accelerator, a light-shielding agent, a filler, a silane coupling agent, a stress-relieving agent, a reactive diluent, a thixotrope, a spacer, an antifoaming agent, a leveling agent, or a polymerization inhibitor.

[0045] One method for producing the sealant for dimming elements of the present invention is to mix a curable resin, a radical polymerization initiator, and additives as needed using a mixer. Examples of the above-mentioned mixing machines include homodispers, homomixers, multi-purpose mixers, planetary mixers, kneaders, and three-roll mixers.

[0046] The present invention provides a sealant for dimming elements that can withstand an illuminance of 100 mW / cm². 2 It is preferable that the glass transition temperature of the cured product obtained by irradiating with light for 30 seconds (hereinafter also referred to as "photocured product") is 60.0°C or higher and less than 85.0°C. By having the glass transition temperature of the above photocured product within this range, the sealant for dimming elements of the present invention can produce a cured product with excellent water penetration resistance and conformability to deformation of the substrate upon light irradiation. It is more preferable that the glass transition temperature of the above photocured product be 65.0°C or higher, and even more preferable that it be 75.0°C or higher. Furthermore, it is more preferable that the glass transition temperature of the above photocured product be less than 83.0°C, even more preferable that it be less than 82.0°C, and even more preferable that it be less than 80.0°C. The glass transition temperature of the above photocured product may be 65.0°C or higher and less than 83.0°C, 75.0°C or higher and less than 82.0°C, or 75.0°C or higher and less than 80.0°C. The wavelength of light used to irradiate the light-modulating element sealant to obtain the above-mentioned photocured product and the photothermocured product described later is appropriately selected according to the type of photoradical polymerization initiator, for example, 340 nm. The glass transition temperature of the above-mentioned photocured product and the glass transition temperature of the photothermocured product described later can be obtained as the temperature of the maximum value of the loss tangent (tanδ) when dynamic viscoelasticity is measured using a dynamic viscoelasticity measuring device under the following conditions: test piece width 5 mm, thickness 0.35 mm, grip width 25 mm, heating rate 10 °C / min, temperature range -80 °C to 200 °C, frequency 10 Hz. For example, the DVA-200 (manufactured by IT Measurement Control Co., Ltd.) can be used as the dynamic viscoelasticity measuring device.

[0047] The present invention provides a sealant for dimming elements that can withstand an illuminance of 100 mW / cm². 2It is preferable that the glass transition temperature of the cured product (hereinafter also referred to as "photothermally cured product") obtained by irradiating with light for 30 seconds and then heating at 120°C for 60 minutes is 1.10 times or less the glass transition temperature of the photothermally cured product. By the glass transition temperature of the photothermally cured product being 1.10 times or less the glass transition temperature of the photothermally cured product, the sealant for the dimming element can be cured with superior low tack properties by light irradiation alone. It is more preferable that the glass transition temperature of the photothermally cured product is 1.03 times or less the glass transition temperature of the photothermally cured product, and most preferably 1.00 times.

[0048] The sealant for dimming elements of the present invention is used to seal a dimming element having a dimming material, and is preferably used when the dimming material is in solid form, and more preferably when it is a PDLC (polymer dispersed liquid crystal). The seal portion formed by the sealant for dimming elements of the present invention is preferably provided around the dimming material.

[0049] Furthermore, the use of a curable resin composition containing a curable resin and a photoradical polymerization initiator, wherein the curable resin contains a (meth)acrylic compound, and the (meth)acrylic compound contains a compound having one (meth)acryloyl group, one or more aromatic rings, and one or more hydroxyl or carboxyl groups in one molecule, as a sealant for dimming elements is also one aspect of the present invention. In the above-mentioned curable resin composition, the components and physical properties are the same as those of the sealant for dimming elements of the present invention. [Effects of the Invention]

[0050] According to the present invention, it is possible to provide a sealant for a dimming element that can be cured by light irradiation to obtain a product with excellent water penetration resistance and conformability to deformation of the substrate. Furthermore, according to the present invention, it is possible to provide a method for using a curable resin composition as a sealant for a dimming element. [Modes for carrying out the invention]

[0051] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0052] (Synthesis of resorcinol-type epoxy acrylates) 1000 parts by mass of a resorcinol-type epoxy compound (Nagase ChemteX, "Denacol EX-201"), 2 parts by mass of p-methoxyphenol as a polymerization inhibitor, 2 parts by mass of triethylamine as a reaction catalyst, and 649 parts by mass of acrylic acid were reacted at 90°C for 5 hours under reflux stirring while introducing air. 100 parts by mass of the resulting reaction product was filtered through a column packed with 10 parts by mass of a natural compound of quartz and kaolin (Hoffmann Minerals, "Silitin V85") to adsorb ionic impurities in the reaction product, thereby obtaining a resorcinol-type epoxy acrylate.

[0053] (Examples 1-19, Comparative Examples 1-5) According to the mixing ratios listed in Tables 1-4, each material was stirred using a planetary agitator, and then uniformly mixed using a ceramic three-roll roller to obtain the dimming element sealants of Examples 1-19 and Comparative Examples 1-5. A "Awatori Rentaro" (manufactured by Shinky Co., Ltd.) was used as the planetary agitator.

[0054] (Glass transition temperature of photocured sealant for dimming elements) The obtained sealant for the dimming element was subjected to UV irradiation using a UV irradiation device (Sun Energy Co., Ltd., "MDB15001N-03") at a wavelength of 340 nm and an illuminance of 100 mW / cm². 2 By irradiating with light for 30 seconds, a photocured material with a thickness of 0.4 mm was obtained. The dynamic viscoelasticity of the obtained photocured material was measured using a dynamic viscoelasticity measuring device under the following conditions: specimen width 5 mm, thickness 0.35 mm, grip width 25 mm, heating rate 10 °C / min, temperature range -80 °C to 200 °C, frequency 10 Hz. The temperature at which the loss tangent (tanδ) was maximized was determined as the glass transition temperature. The dynamic viscoelasticity measuring device used was the DVA-200 (manufactured by IT Measurement Control Co., Ltd.). The results are shown in Tables 1 to 4.

[0055] <Rating> The following evaluations were performed on the obtained sealant for dimming elements. The results are shown in Tables 1-4.

[0056] (High temperature water resistance) The obtained light-adjusting element sealant was applied to a glass substrate in five drop-type dots with a diameter of 3 mm and at 3 mm intervals, and then the light-adjusting element sealant was cured to obtain a test specimen. For the light-adjusting element sealants obtained in Examples 1-8, 10-19, and Comparative Examples 1-5, UV irradiation was performed using a UV irradiation device (Sun Energy Co., Ltd., "MDB15001N-03") at a wavelength of 340 nm and an illuminance of 100 mW / cm². 2 The material was cured by irradiating it with light for 30 seconds and then heating it at 120°C for 60 minutes. Furthermore, the sealant for the dimming element obtained in Example 9 was cured using a UV irradiation device (Sun Energy Co., Ltd., "MDB15001N-03") at a wavelength of 340 nm and an illuminance of 100 mW / cm². 2 It was cured by irradiating it with light for 30 seconds. The obtained test specimens were left in 85°C hot water for 2 hours. After that, the test specimens were removed from the hot water, and each cured portion of the dimming element sealant was rubbed five times using a stainless steel spoon with a spatula (AS ONE Corporation, "Spoon (with spatula)"), and then observed visually. The high-temperature water resistance was evaluated according to the following criteria. ◎: If there is no peeling of the cured portion of the sealant for all dimming elements. ○: If there is peeling of the cured portion of the sealant for the dimming element in one to three locations. △: If there is peeling of the cured portion of the sealant for the dimmer element in 4 locations. ×: If there is peeling of the cured portion of the sealant for all dimming elements.

[0057] (moisture intrusion resistance) The obtained light-adjusting element sealant was applied in a 500 μm width around a light-adjusting film (manufactured by Kyushu Nanotech Co., Ltd., "nanotec film type 1") placed on a glass substrate, and then exposed to UV light using a UV irradiation device (manufactured by Sun Energy Co., Ltd., "MDB15001N-03") at a wavelength of 340 nm and an illuminance of 100 mW / cm². 2Test specimens were obtained by curing the material by irradiating it with light for 30 seconds. The obtained test specimens were left in an environment of 80°C and 90%RH for 100 hours and then observed visually. The penetration of moisture into the light-adjusting film was confirmed, and the moisture penetration resistance was evaluated according to the following criteria. ○: If no moisture penetrated the system. △: In cases where moisture penetrates into the dimming film from a portion of the cured sealant for the dimming element. ×: If moisture penetrates into the dimming film from most or all of the cured portion of the sealant for the dimming element.

[0058] (Followability) Test specimens obtained in the same manner as described above for "(water penetration resistance)" were left in an environment of 80°C and 90%RH for 100 hours and then visually observed. The presence or absence of peeling of the cured portion due to warping of the glass substrate or dimming film was checked, and the conformability was evaluated according to the following criteria. ○: If there is no peeling of the cured portion of the sealant for the dimming element. △: In cases where a portion of the cured sealant for the dimming element has peeled off. ×: If a large portion or the entire cured portion of the sealant for the dimming element has peeled off.

[0059] [Table 1]

[0060] [Table 2]

[0061] [Table 3]

[0062] [Table 4] [Industrial applicability]

[0063] According to the present invention, it is possible to provide a sealant for a dimming element that can be cured by light irradiation to obtain a product with excellent water penetration resistance and conformability to deformation of the substrate. Furthermore, according to the present invention, it is possible to provide a method for using a curable resin composition as a sealant for a dimming element.

Claims

1. A sealant for a dimming element used to seal a dimming element having a dimming material, It contains a curable resin and a photoradical polymerization initiator. The curable resin contains a (meth)acrylic compound, The (meth)acrylic compound includes a compound having one (meth)acryloyl group, one or more aromatic rings, and one or more hydroxyl groups or carboxyl groups in one molecule. The aforementioned sealant for the dimming element has an illuminance of 100 mW / cm². ２ The glass transition temperature of the cured product obtained by irradiating it with light for 30 seconds is 60.0°C or higher and less than 85.0°C. A sealant for dimming elements characterized by the following features.

2. The sealant for a dimming element according to Claim 1, wherein the (meth)acrylic compound comprises at least one selected from the group consisting of a compound having one (meth)acryloyl group and one or more structures represented by the following formula (1) in one molecule, and a compound having one (meth)acryloyl group and one or more structures represented by the following formula (2) in one molecule. 【Chemistry 1】 In equation (1), * indicates the bonding position. 【Chemistry 2】 In equation (2), * indicates the bonding position.

3. The light-modulating material is a PDLC, as described in claim 1 or 2, as a sealant for a light-modulating element.

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