Sealing agent for light control element and use of curable resin composition as sealing agent for light control element

Abstract

A purpose of the present invention is to provide a sealing agent for a light control element, with which it is possible to obtain, by light irradiation, a cured product that has excellent resistance to ingress of moisture and excellent followability to deformation of a base material. Another purpose of the present invention is to provide a method for using a curable resin composition as the sealing agent for a light control element. The present invention is a sealing agent for a light control element, which is used for the purpose of sealing a light control element that has a light control material, and which contains a curable resin and a radical photopolymerization initiator, wherein: the curable resin contains a (meth)acrylic compound; and the (meth)acrylic compound includes a compound that has one (meth)acryloyl group, one or more aromatic rings, and one or more hydroxyl groups or carboxy groups in each molecule.

Description

Sealant for dimming element and use of curable resin composition as sealant for dimming element

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

[0002] Dimming elements that change the light transmittance by applying a voltage are widely used. For example, in buildings, automobiles, etc., laminated glass containing a dimming element 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 a dimming element, a sealant is usually used to protect the dimming material from moisture, contaminants, etc. For example, Patent Document 1 discloses that in order to protect a liquid crystal layer from moisture, acid, ultraviolet rays, etc., a seal portion using a curable resin is provided by coating formation at the peripheral portion of a dimming film.

[0003] Japanese Patent Application Laid-Open No. 2020-95084

[0004] Conventionally, as a sealant for a dimming element, those having excellent performance (moisture intrusion resistance) in preventing moisture from entering the dimming material have been used. However, a sealant with excellent moisture intrusion resistance may not be able to follow the deformation of the film or glass. For example, when the laminated glass is exposed to a high temperature and high humidity environment for a long time and warping occurs in the base materials such as the film and glass, the sealant may peel off. On the other hand, when the flexibility of the sealant is improved to make it excellent in followability to the deformation of the base material, it may not be able to sufficiently prevent the intrusion of moisture. Furthermore, from the viewpoint of shortening the working process, there has been a demand for a sealant that can obtain a cured product having excellent moisture intrusion resistance and followability by light irradiation.

[0005] An object of the present invention is to provide a sealant for a dimming element that can obtain a cured product having excellent moisture intrusion resistance and followability to the deformation of the base material by light irradiation. Another object of the present invention is to provide a method for using a curable resin composition as the sealant for the dimming element.

[0006] Disclosure 1 is a sealant for dimming elements 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 or carboxyl groups in one molecule. Disclosure 2 is the sealant for dimming elements of Disclosure 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. Disclosure 3 is the sealant for dimming elements of Disclosure 1, which is illuminating at an illuminance of 100 mW / cm ２ The sealant for a dimming element according to Disclosure 1 or 2 is wherein the glass transition temperature of the cured product obtained by irradiating with light for 30 seconds is 60.0°C or higher and less than 85.0°C. Disclosure 4 is the sealant for a dimming element according to Disclosure 1, 2 or 3, wherein the dimming material is PDLC. Disclosure 5 is the use of a curable resin composition as a sealant for a dimming element, 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.

[0007]

[0008] In equation (1), * indicates the bonding position.

[0009]

[0010] In equation (2), * indicates the bonding position.

[0011] The present invention is described in detail below. The inventors have discovered 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, it is possible to obtain a cured product with excellent water penetration resistance and conformability to deformation of the substrate upon light irradiation, thereby completing the present invention.

[0012] The sealant for dimming elements of the present invention contains a curable resin. The curable resin contains a (meth)acrylic compound. By containing the (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 groups 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 a monofunctional (meth)acrylic compound according to the present invention may have in one molecule, but the practical upper limit is three. The number of aromatic rings is counted as, for example, one for a benzene ring, two for a naphthalene ring, and three for anthracene rings.

[0015] There is no particular preferred upper limit to the number of hydroxyl groups or carboxyl groups in one molecule of the monofunctional (meth)acrylic compound according to the present invention, but the substantial upper limit is 2. The monofunctional (meth)acrylic compound according to the present invention may have both hydroxyl groups and carboxyl groups, in which case the number of hydroxyl groups or carboxyl groups in one molecule of the monofunctional (meth)acrylic compound according to the present invention refers to the sum of the number of hydroxyl groups and the number of carboxyl groups. Furthermore, the above (meth)acrylic compound may include, as the monofunctional (meth)acrylic compound according to the present invention, a combination of 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.

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

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

[0018] The preferred lower limit for 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 preferred 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, the resulting sealant for dimming elements will have a cured product that is superior in water penetration resistance and conformability to deformation of the substrate. When the content of the monofunctional (meth)acrylic compound according to the present invention is 50 parts by mass or less, the resulting sealant for dimming elements will have superior curability and adhesion. The more preferred lower limit for the content of the monofunctional (meth)acrylic compound according to the present invention is 25 parts by mass, and the more preferred 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 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 "bifunctional or more (meth)acrylic compound"). By including the above bifunctional or more (meth)acrylic compound as the above (meth)acrylic compound, the sealant for dimming elements of the present invention has superior curability and adhesion.

[0020] Examples of the above-mentioned bifunctional or more (meth)acrylic compounds include epoxy (meth)acrylate, (meth)acrylic acid ester compounds, urethane (meth)acrylate, etc., which have two or more (meth)acryloyl groups in one molecule. Among these, the above-mentioned bifunctional or more (meth)acrylic compounds preferably include epoxy (meth)acrylate from the viewpoint of low staining (especially low liquid crystal staining). In this specification, "epoxy (meth)acrylate" means a compound obtained by reacting all epoxy groups in an epoxy compound with (meth)acrylic acid.

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

[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 above-mentioned polyols 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 a hydroxyl group include hydroxyalkyl (meth)acrylate, mono(meth)acrylate of a dihydric alcohol, mono(meth)acrylate or di(meth)acrylate of a trihydric alcohol, and epoxy (meth)acrylate. Examples of hydroxyalkyl (meth)acrylate include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate. Examples of dihydric alcohol include ethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, and polyethylene glycol. Examples of trihydric alcohol include trimethylolethane, trimethylolpropane, and glycerin. Examples of epoxy (meth)acrylate 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, since a cured product with superior low tack can be obtained by light irradiation alone, and superior high-temperature water resistance and water penetration resistance can be achieved, 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., 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 above-mentioned (meth)acrylic compound, examples of such other curable resins include epoxy compounds. Examples of epoxy compounds used as the above-mentioned other curable resins include those described as epoxy compounds that serve as raw materials for the 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, thioxanthone compounds, etc. Specific examples of the above-mentioned photoradical polymerization initiators include 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 content of the above-mentioned radical polymerization initiator within this range results in a sealant for dimming elements having superior storage stability and photocurability. A more preferred lower limit for the content of the above-mentioned radical polymerization initiator is 0.1 parts by mass and a more preferred upper limit is 5 parts by mass. The content of the above-mentioned photoradical polymerization initiator per 100 parts by mass of the above-mentioned 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 azo compounds include, for example, those having a structure in which multiple units such as polyalkylene oxide or polydimethylsiloxane 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 glycol, and polycondensates of 4,4'-azobis(4-cyanopentanoic acid) and polydimethylsiloxane having a terminal amino group. Examples of the above 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 content of the above-mentioned thermal radical polymerization initiator is preferably 0.01 parts by mass and preferably 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 preferable lower limit for the content of the above-mentioned thermal radical polymerization initiator is 0.1 parts by mass, a more preferable upper limit is 5 parts by mass, and an even more preferable upper limit is 0.2 parts by mass. The content of the above-mentioned thermal radical polymerization initiator per 100 parts by mass of the above-mentioned 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 the dimming element of the present invention may contain a heat curing agent. In particular, when the curable resin contains an epoxy compound as another curable resin, it is preferable that the sealant for the dimming element of the present invention contains a heat curing agent.

[0041] Examples of the heat curing agent include organic acid hydrazides, imidazole derivatives, amine compounds, polyhydric phenol compounds, acid anhydrides, and the like. Among them, organic acid hydrazides are preferably used.

[0042] Examples of the organic acid hydrazide include sebacic acid dihydrazide, isophthalic acid dihydrazide, adipic acid dihydrazide, malonic acid dihydrazide, and the like.

[0043] The content of the heat curing agent preferably has a lower limit of 1 part by mass and an upper limit of 50 parts by mass with respect to 100 parts by mass of the curable resin. When the content of the heat curing agent is within this range, the heat curability can be made excellent without deteriorating the coating property and the like of the obtained sealant for the dimming element. A more preferable upper limit of the content of the heat curing agent is 30 parts by mass.

[0044] The sealant for the dimming element of the present invention may further contain additives such as a curing accelerator, a light shielding agent, a filler, a silane coupling agent, a stress reliever, a reactive diluent, a thixotropic agent, a spacer, an antifoaming agent, a leveling agent, a polymerization inhibitor, etc., as necessary.

[0045] Examples of the method for producing the sealant for the dimming element of the present invention include a method of mixing a curable resin, a radical polymerization initiator, and additives used as necessary using a mixer. Examples of the mixer include a homodisper, a homomixer, a universal mixer, a planetary mixer, a kneader, a three-roll mill, and the like.

[0046] The sealant for the dimming element of the present invention has an illuminance of 100 mW / cm on the sealant for the dimming element ２It 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 be 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, or 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. ２ It 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 curable resin composition, the components and physical properties are the same as those of the sealant for dimming elements of the present 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.

[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 Epoxyacrylate) 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 resorcinol-type epoxy acrylate.

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

[0054] (Glass transition temperature of photocured product of sealant for dimming element) The obtained sealant for 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 irradiance of 100 mW / cm². ２ A photocured material with a thickness of 0.4 mm was obtained by irradiating it with light for 30 seconds. 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] <Evaluation> The following evaluation was performed on the obtained sealant for dimming elements. The results are shown in Tables 1 to 4.

[0056] (High Temperature Water Resistance) The obtained sealant for the dimming element 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 sealant for the dimming element was cured to obtain a test specimen. For the sealants for the dimming element obtained in Examples 1-8, 10-19, and Comparative Examples 1-5, a UV irradiation device (Sun Energy Co., Ltd., "MDB15001N-03") was used with a wavelength of 340 nm and an illuminance of 100 mW / cm². ２ The material was irradiated with light for 30 seconds, then heated at 120°C for 60 minutes to cure. Furthermore, the sealant for the dimming element obtained in Example 9 was treated using a UV irradiation device (Sun Energy Co., Ltd., "MDB15001N-03") at a wavelength of 340 nm and an illuminance of 100 mW / cm². ２The material was cured by irradiating it with light for 30 seconds. The resulting 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 Co., Ltd., "Spoon (with spatula)"), and then observed visually. The high temperature water resistance was evaluated according to the following criteria: ◎: No peeling in any of the cured portions of the dimming element sealant ○: Peeling in 1 to 3 portions of the cured portion of the dimming element sealant △: Peeling in 4 portions of the cured portion of the dimming element sealant ×: Peeling in all of the cured portions of the dimming element sealant

[0057] (Water Infiltration Resistance) The obtained sealant for the dimming element was applied in a 500 μm width around the dimming film (manufactured by Kyushu Nanotec 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. ２ Test 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 dimming film was checked, and the moisture penetration resistance was evaluated according to the following criteria: ○: No moisture penetration occurred. △: Moisture penetrated into the dimming film from a part of the cured portion of the dimming element sealant. ×: Moisture penetrated into the dimming film from most or all of the cured portion of the dimming element sealant.

[0058] (Followability) Test specimens obtained in the same manner as described above for "(Water Infiltration Resistance)" were left in an environment of 80°C and 90% RH for 100 hours and then observed visually. The presence or absence of peeling of the cured portion due to warping of the glass substrate or dimming film was checked, and the followability was evaluated according to the following criteria: ○: No peeling of the cured portion of the dimming element sealant △: Some peeling of the cured portion of the dimming element sealant ×: Most or all of the cured portion of the dimming element sealant peeling

[0059]

[0060]

[0061]

[0062]

[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, 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.

2. The (meth)acrylic compound comprises at least one selected from the group consisting of compounds having one (meth)acryloyl group and one or more structures represented by the following formula (1) in one molecule, and compounds having one (meth)acryloyl group and one or more structures represented by the following formula (2) in one molecule. In equation (1), * indicates the bonding position. In equation (2), * indicates the bonding position.

3. The sealant for the dimming element has an illuminance of 100 mW / cm ２ The sealant for a dimming element according to claim 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.

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

5. Use of a curable resin composition as a sealant for a dimming element, wherein the curable resin contains a photoradical polymerization initiator, 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.

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