Sealing agent for dimming element

Abstract

The purpose of the present invention is to provide a sealing agent for a dimming element, the sealing agent being excellent in adhesiveness and low-staining properties. The present invention is a sealing agent for a dimming element, the sealing agent comprising a curable resin, a photo radical polymerization initiator, and an amine-based thermosetting agent, wherein: the curable resin includes a (meth)acrylic compound having no epoxy group; the (meth)acrylic compound includes a compound having two or more (meth)acryloyl groups in one molecule; and the curable resin includes no epoxy compound or includes 5 parts by mass or less of an epoxy compound in 100 parts by mass of the curable resin.

Description

Sealant for light-control devices

[0001] The present invention relates to a sealant for a light-adjusting element.

[0002] Liquid crystal dimming elements using liquid crystal materials and electrochromic elements using electrochromic compounds are widely used as dimming elements whose light transmittance changes when a voltage is applied. Liquid crystal dimming elements are dimming elements that control the amount of light transmitted by changing the orientation of liquid crystal molecules by changing the potential difference between transparent electrode layers, and have excellent responsiveness. Electrochromic elements are dimming elements that exhibit reversible color changes due to the electrochemical oxidation-reduction reaction of electrochromic compounds. They can maintain their colored state until they are decolorized, allowing them to be driven with low power consumption.

[0003] In such light-adjusting elements, a sealant is used to seal the liquid crystal, electrochromic compound solution, etc. For example, Patent Document 1 discloses the use of a sealant containing an epoxy compound to surround the liquid crystal layer of the light-adjusting unit, and Patent Document 2 discloses the use of a sealant containing a (meth)acrylic compound or an epoxy compound as a sealing material for the electrochromic element.

[0004] JP 2021-117456 A Patent No. 7327621 A

[0005] Sealant using epoxy compounds has excellent adhesive properties but has the problem of easily contaminating liquid crystals, electrochromic compound solutions, etc. On the other hand, sealant using (meth)acrylic compounds has low contamination properties (excellent low contamination properties) but has the problem of sometimes not being able to obtain sufficient adhesion. The present invention aims to provide a sealant for light control elements that has excellent adhesive properties and low contamination properties.

[0006] Disclosure 1 is a sealant for light control devices containing a curable resin, a photoradical polymerization initiator, and an amine-based heat curing agent, wherein the curable resin contains a (meth)acrylic compound without an epoxy group, the (meth)acrylic compound contains a compound having two or more (meth)acryloyl groups in one molecule, and the curable resin does not contain an epoxy compound or contains 5 parts by mass or less of an epoxy compound per 100 parts by mass of the curable resin. Disclosure 2 is the sealant for light control devices of Disclosure 1, wherein the curable resin does not contain an epoxy compound. Disclosure 3 is the sealant for light control devices of Disclosure 1 or 2, wherein the content of the amine-based heat curing agent per 100 parts by mass of the curable resin is 0.5 parts by mass or more and 3.0 parts by mass or less. Disclosure 4 is the sealant for light control devices according to Disclosure 1, 2, or 3, wherein the content of the amine-based heat curing agent per 100 parts by mass of the compound having two or more (meth)acryloyl groups per molecule is 0.5 parts by mass or more and 3.0 parts by mass or less. Disclosure 5 is the sealant for light control devices according to Disclosure 1, 2, 3, or 4, wherein the amine-based heat curing agent contains a hydrazide compound. Disclosure 6 is the sealant for light control devices according to Disclosure 1, 2, 3, 4, or 5, which is used to seal an electrochromic device. The present invention is described in detail below.

[0007] The present inventors have investigated the possibility of improving the adhesiveness of a light-controlling element sealant containing a (meth)acrylic compound including a compound having two or more (meth)acryloyl groups in one molecule and a photoradical polymerization initiator by further blending an amine-based heat curing agent and by subjecting the amine-based heat curing agent to a Michael addition reaction with the (meth)acrylic compound. As a result, they have found that a light-controlling element sealant can be obtained that has excellent adhesiveness and also excellent low contamination properties by using no epoxy compound or by using a small amount of epoxy compound, and have thus completed the present invention.

[0008] The sealant for light control devices of the present invention contains a curable resin. The curable resin contains a (meth)acrylic compound that does not have an epoxy group. By containing the (meth)acrylic compound, the sealant for light control devices of the present invention has excellent low-staining properties. In this specification, the term "(meth)acrylic" means acrylic or methacrylic, the term "(meth)acrylic compound" means a compound having a (meth)acryloyl group, and the term "(meth)acryloyl" means acryloyl or methacryloyl.

[0009] The (meth)acrylic compound includes a compound having two or more (meth)acryloyl groups in one molecule (hereinafter also referred to as a "difunctional or higher functional (meth)acrylic compound"). By including the difunctional or higher functional (meth)acrylic compound as the (meth)acrylic compound in combination with a photoradical polymerization initiator described later and an amine-based heat curing agent described later, the sealing agent for light control devices of the present invention has excellent curability and adhesiveness.

[0010] Among the above-mentioned difunctional or more functional (meth)acrylic compounds, examples of bifunctional (meth)acrylic compounds having two (meth)acryloyl groups in one molecule include bifunctional epoxy (meth)acrylates, bifunctional (meth)acrylic acid ester compounds, and bifunctional urethane (meth)acrylates. Among these, bifunctional epoxy (meth)acrylates are preferred. In this specification, the term "epoxy (meth)acrylate" refers to a compound in which all epoxy groups in an epoxy compound have reacted with (meth)acrylic acid.

[0011] Examples of the difunctional epoxy (meth)acrylate include those obtained by reacting a difunctional epoxy compound having two epoxy groups in one molecule with (meth)acrylic acid in the presence of a basic catalyst according to a conventional method.

[0012] Examples of the bifunctional epoxy compound that serves as a raw material for the bifunctional epoxy (meth)acrylate include bisphenol A-type epoxy compounds, bisphenol F-type epoxy compounds, bisphenol S-type epoxy compounds, 2,2'-diallyl bisphenol 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, glycidylamine-type epoxy compounds, alkyl polyol-type epoxy compounds, rubber-modified epoxy compounds, and glycidyl ester compounds. Among these, resorcinol-type epoxy compounds are preferred from the viewpoint of improving reliability. That is, the bifunctional or higher (meth)acrylic compound preferably contains a resorcinol-type epoxy (meth)acrylate.

[0013] When the difunctional or higher functional (meth)acrylic compound contains the resorcinol-type epoxy (meth)acrylate, the content of the resorcinol-type epoxy (meth)acrylate in 100 parts by mass of the curable resin is preferably 10 parts by mass at the lower limit and 90 parts by mass at the upper limit. By ensuring that the content of the resorcinol-type epoxy (meth)acrylate is within this range, the resulting sealant for light control devices has superior reliability. The content of the resorcinol-type epoxy (meth)acrylate is more preferably 30 parts by mass at the lower limit and 80 parts by mass at the upper limit.

[0014] Examples of the bifunctional (meth)acrylic acid ester compound 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, polypropylene glycol di(meth)acrylate, tert-butyl 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, dimethyloldicyclopentadienyl di(meth)acrylate, ethylene oxide-modified isocyanuric acid 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.

[0015] The difunctional urethane (meth)acrylate can be obtained, for example, by reacting a difunctional isocyanate compound with a (meth)acrylic acid derivative having a hydroxyl group in the presence of a catalytic amount of a tin compound.

[0016] Examples of the bifunctional isocyanate compound 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, tolidine diisocyanate, xylylene diisocyanate (XDI), hydrogenated XDI, lysine diisocyanate, and tetramethylxylylene diisocyanate.

[0017] Furthermore, the bifunctional isocyanate compound may be a chain-extended bifunctional isocyanate compound obtained by reacting a polyol with an excess of the bifunctional isocyanate compound. Examples of the polyol include ethylene glycol, propylene glycol, glycerin, sorbitol, trimethylolpropane, carbonate diol, polyether diol, polyester diol, and polycaprolactone diol.

[0018] Examples of the (meth)acrylic acid derivatives having a hydroxyl group include hydroxyalkyl mono(meth)acrylates, dihydric alcohol mono(meth)acrylates, and trihydric alcohol mono(meth)acrylates. Examples of the hydroxyalkyl mono(meth)acrylates include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate. Examples of the dihydric alcohols include ethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, and polyethylene glycol. Examples of the trihydric alcohols include trimethylolethane, trimethylolpropane, and glycerin.

[0019] Among the difunctional or higher (meth)acrylic compounds, examples of trifunctional or higher (meth)acrylic compounds having three or more (meth)acryloyl groups in one molecule 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.

[0020] The preferred lower limit of the content of the difunctional or higher (meth)acrylic compound per 100 parts by mass of the curable resin is 90 parts by mass. When the content of the difunctional or higher (meth)acrylic compound is 90 parts by mass or more, the resulting sealant for light control devices has excellent low-contamination properties. The more preferred lower limit of the content of the difunctional or higher (meth)acrylic compound is 95 parts by mass, and even more preferred lower limit is 97 parts by mass. It is particularly preferred that the content of the difunctional or higher (meth)acrylic compound is 100 parts by mass, that is, the curable resin is composed solely of the difunctional or higher (meth)acrylic compound.

[0021] The (meth)acrylic compound may include a monofunctional (meth)acrylic compound having one (meth)acryloyl group in one molecule.

[0022] The curable resin does not contain an epoxy compound or contains 5 parts by mass or less of an epoxy compound per 100 parts by mass of the curable resin. By not containing the epoxy compound or, even if the epoxy compound is contained, keeping the content of the epoxy compound at 5 parts by mass or less, the sealant for a light control element of the present invention has excellent low-contamination properties. In this specification, the term "epoxy compound" refers to a compound having an epoxy group.

[0023] Examples of the epoxy compound include bisphenol A type epoxy compounds, bisphenol F type epoxy compounds, bisphenol S type epoxy compounds, 2,2'-diallyl bisphenol 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, ortho-cresol 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, and glycidyl ester compounds.

[0024] The epoxy compound also includes a partially (meth)acrylic-modified epoxy compound. In this specification, the partially (meth)acrylic-modified epoxy compound refers to a compound having one or more epoxy groups and one or more (meth)acryloyl groups in one molecule, which is obtained by reacting a portion of the epoxy groups of an epoxy compound having two or more epoxy groups with (meth)acrylic acid. Although the partially (meth)acrylic-modified epoxy compound has a (meth)acryloyl group, it is treated as the epoxy compound rather than the (meth)acrylic compound.

[0025] The curable resin preferably does not contain an epoxy compound. On the other hand, when the curable resin contains the epoxy compound, the upper limit of the content of the epoxy compound per 100 parts by mass of the curable resin is 5 parts by mass. When the content of the epoxy compound is 5 parts by mass or less, the resulting sealant for light control devices has excellent low-contamination properties. The upper limit of the content of the epoxy compound is preferably 3 parts by mass, and more preferably 1 part by mass.

[0026] The preferred lower limit of the total content of the curable resin in 100 parts by mass of the sealant for light control devices of the present invention is 65 parts by mass, and the preferred upper limit is 96 parts by mass. When the total content of the curable resin is within this range, the resulting sealant for light control devices has better curability and adhesiveness. The more preferred lower limit of the total content of the curable resin is 70 parts by mass, and the more preferred upper limit is 88 parts by mass.

[0027] The sealing agent for light control elements of the present invention contains a photoradical polymerization initiator. Examples of the photoradical polymerization initiator include benzophenone compounds, acetophenone compounds, acylphosphine oxide compounds, titanocene compounds, oxime ester compounds, benzoin ether compounds, and thioxanthone compounds. Specific examples of the photoradical polymerization initiator include 1-hydroxycyclohexyl phenyl ketone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone, 2-(dimethylamino)-2-((4-methylphenyl)methyl)-1-(4-(4-morpholinyl)phenyl)-1-butanone, 2,2-dimethoxy-1,2-diphenylethan-1-one, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, and 2-methyl-1-(4-methylthiophenyl) 2-morpholinopropan-1-one, 1-(4-(2-hydroxyethoxy)-phenyl)-2-hydroxy-2-methyl-1-propan-1-one, 1-(4-(phenylthio)phenyl)-1,2-octanedione 2-(O-benzoyloxime), 2-(acetoxyimino)-1-(4-(4-(2-hydroxyethoxy)phenylthio)phenyl)propan-1-one, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,4-dimethylthioxanthen-9-one, and the like.

[0028] The content of the photoradical polymerization initiator is preferably 0.01 parts by mass at the lower limit and 10 parts by mass at the upper limit relative to 100 parts by mass of the curable resin. When the content of the photoradical polymerization initiator is within this range, the resulting sealant for light-controlling elements has better storage stability and photocurability. The content of the photoradical polymerization initiator is more preferably 0.1 parts by mass at the lower limit and 5 parts by mass at the upper limit.

[0029] The sealing agent for light-controlling elements of the present invention may contain a thermal radical polymerization initiator. Examples of the thermal radical polymerization initiator include those composed of an azo compound or an organic peroxide. Among them, initiators composed of an azo compound (hereinafter also referred to as "azo initiators") are preferred from the viewpoint of suppressing contamination of liquid crystals, electrochromic compound solutions, etc. The thermal radical polymerization initiators may be used alone or in combination of two or more.

[0030] Examples of the azo compound include those having a structure in which multiple units such as polyalkylene oxide or polydimethylsiloxane are bonded via azo groups. As the polymeric azo compound having a structure in which multiple units such as polyalkylene oxide are bonded via azo groups, those having a polyethylene oxide structure are preferred. Specific examples of the azo compound include 2,2'-azobis(2,4-dimethylvaleronitrile), 4,4'-azobis(4-cyanovaleric acid), polycondensates of 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 azo initiator 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.).

[0031] Examples of the organic peroxide include ketone peroxides, peroxyketals, hydroperoxides, dialkyl peroxides, peroxyesters, diacyl peroxides, and peroxydicarbonates.

[0032] The content of the thermal radical polymerization initiator is preferably 0.01 parts by mass at the lower limit and 10 parts by mass at the upper limit relative to 100 parts by mass of the curable resin. By using the thermal radical polymerization initiator in this range, the resulting sealant for light-controlling elements has better storage stability and thermosetting properties. The more preferred lower limit of the content of the thermal radical polymerization initiator is 0.1 parts by mass, and the more preferred upper limit is 5 parts by mass.

[0033] The light-adjusting element sealant of the present invention contains an amine-based heat curing agent. The amine-based heat curing agent acts as a nucleophile in the Michael addition reaction with the (meth)acrylic compound. Even if the light-adjusting element sealant of the present invention does not contain the epoxy compound or contains only a small amount of the epoxy compound, the light-adjusting element sealant exhibits excellent adhesive properties due to the progression of the Michael addition reaction between the (meth)acrylic compound and the amine-based heat curing agent. Furthermore, when the light-adjusting element sealant of the present invention contains a small amount of an epoxy compound, the amine-based heat curing agent also acts as a curing agent for the epoxy compound.

[0034] Examples of the amine-based heat curing agent include hydrazide compounds, imidazole derivatives, and amine adduct compounds. Among these, primary amine compounds and secondary amine compounds are preferred, and hydrazide compounds are more preferred. In this specification, the term "hydrazide compound" refers to a compound having a hydrazide group.

[0035] Examples of the hydrazide compound include sebacic acid dihydrazide, isophthalic acid dihydrazide, adipic acid dihydrazide, and malonic acid dihydrazide.

[0036] The preferred lower limit of the content of the amine-based heat curing agent per 100 parts by mass of the curable resin is 0.5 parts by mass, and the preferred upper limit is 3.0 parts by mass. When the content of the amine-based heat curing agent per 100 parts by mass of the curable resin is 0.5 parts by mass or more, the resulting sealant for light control devices has superior adhesive properties. When the content of the amine-based heat curing agent per 100 parts by mass of the curable resin is 3.0 parts by mass or less, the resulting sealant for light control devices has superior low-contamination properties. A more preferred lower limit of the content of the amine-based heat curing agent per 100 parts by mass of the curable resin is 1.0 parts by mass, and a more preferred upper limit is 1.5 parts by mass. Furthermore, a preferred lower limit of the content of the amine-based heat curing agent per 100 parts by mass of the bifunctional or higher (meth)acrylic compound is 0.5 parts by mass, and a preferred upper limit is 3.0 parts by mass. When the content of the amine-based heat curing agent per 100 parts by mass of the difunctional or higher (meth)acrylic compound is 0.5 parts by mass or more, the resulting sealant for light control devices has superior adhesiveness. When the content of the amine-based heat curing agent per 100 parts by mass of the difunctional or higher (meth)acrylic compound is 3.0 parts by mass or less, the resulting sealant for light control devices has superior low-staining properties. A more preferred lower limit of the content of the amine-based heat curing agent per 100 parts by mass of the difunctional or higher (meth)acrylic compound is 1.0 part by mass, and a more preferred upper limit is 1.5 parts by mass.

[0037] The sealant for a light control element of the present invention may further contain a filler for the purposes of improving viscosity, further improving adhesion due to a stress dispersion effect, improving the linear expansion coefficient, further improving moisture permeability, and the like.

[0038] The filler may be an inorganic filler or an organic filler. Examples of the inorganic filler include silica, talc, glass beads, asbestos, gypsum, diatomaceous earth, smectite, bentonite, montmorillonite, sericite, activated clay, alumina, zinc oxide, iron oxide, magnesium oxide, tin oxide, titanium oxide, calcium carbonate, magnesium carbonate, magnesium hydroxide, aluminum hydroxide, aluminum nitride, silicon nitride, barium sulfate, and calcium silicate. Examples of the organic filler include polyester fine particles, polyurethane fine particles, vinyl polymer fine particles, and (meth)acrylic polymer fine particles. The organic filler may have a core-shell structure. The fillers may be used alone or in combination of two or more.

[0039] When the filler is contained, the preferred lower limit of the content of the filler relative to 100 parts by mass of the curable resin is 10 parts by mass, and the preferred upper limit is 50 parts by mass. By having the content of the filler in this range, excellent effects such as improved adhesion can be achieved without deteriorating the coating properties, etc. A more preferred upper limit of the content of the filler is 40 parts by mass.

[0040] The light control element sealant of the present invention preferably further contains a silane coupling agent. The silane coupling agent mainly serves as an adhesion aid for favorably adhering the light control element sealant to a substrate or the like. Suitable examples of the silane coupling agent include 3-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-glycidoxypropyltrimethoxysilane.

[0041] The preferred lower limit of the content of the silane coupling agent relative to 100 parts by mass of the curable resin is 0.8 parts by mass, and the preferred upper limit is 3.4 parts by mass. By having the content of the silane coupling agent in this range, the effect of improving adhesion while suppressing the occurrence of contamination is excellent. The more preferred lower limit of the content of the silane coupling agent is 1.0 parts by mass, and the more preferred upper limit is 3.0 parts by mass.

[0042] The sealing agent for a light-controlling element of the present invention may further contain additives such as a light-shielding agent, a stress relaxation agent, a reactive diluent, a thixotropic agent, a spacer, a curing accelerator, an antifoaming agent, a leveling agent, and a polymerization inhibitor, as necessary.

[0043] Examples of a method for producing the sealant for a light-controlling element of the present invention include a method of mixing a curable resin, a photoradical polymerization initiator, an amine-based heat curing agent, and other components such as an inorganic filler and a silane coupling agent using a mixer. Examples of the mixer include a homodisper, a homomixer, a universal mixer, a planetary mixer, a kneader, and a three-roll mill.

[0044] The sealing agent for light control devices of the present invention is preferably used for sealing electrochromic devices. When used for sealing the electrochromic device, the sealing portion formed by the sealing agent for light control devices of the present invention is preferably provided around a solution containing an electrochromic compound and an electrolyte.

[0045] According to the present invention, it is possible to provide a sealant for a light control device that has excellent adhesiveness and low contamination.

[0046] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0047] (Examples 1 to 20, Comparative Examples 1 to 8) According to the blending ratios shown in Tables 1 to 3, each material was stirred with a planetary stirrer and then uniformly mixed with a ceramic triple roll to obtain sealants for light control elements of Examples 1 to 20 and Comparative Examples 1 to 8. Awatori Mixer (manufactured by Thinky Corporation) was used as the planetary stirrer.

[0048] <Evaluation> The sealants for light control devices obtained in the examples and comparative examples were evaluated as follows. The results are shown in Tables 1 to 3.

[0049] (Adhesion) The obtained sealant for light control elements was dropped in small drops onto one of two glass substrates (length 4.5 mm, width 2.5 mm) with an ITO thin film. The other glass substrate with an ITO thin film was then attached in a cross shape to this, and the adhesive was applied with a metal halide lamp at 100 mW / cm ２Test pieces were obtained by irradiating the test pieces with ultraviolet light of 1000 kJ / cm for 30 seconds, followed by heating at 120°C for 60 minutes. The edge of the substrate of the test pieces was pressed into a metal cylinder with a radius of 5 mm at a speed of 5 mm / min, and the strength at which panel peeling occurred was measured. The obtained measured value (kgf) was divided by the diameter (cm) of the joint to determine the adhesive strength, and the adhesiveness was evaluated according to the following criteria: ◎: When the adhesive strength was 2.5 kgf / cm or more ○: When the adhesive strength was 2.0 kgf / cm or more but less than 2.5 kgf / cm △: When the adhesive strength was 1.5 kgf / cm or more but less than 2.0 kgf / cm ×: When the adhesive strength was less than 1.5 kgf / cm

[0050] (Moisture Permeability Prevention) The obtained sealant for a light control element was applied to a smooth release film using a coater to a thickness of 200 to 300 μm. Then, the sealant was applied to a smooth release film using a metal halide lamp at 100 mW / cm ２ The sealant for light control devices was cured by irradiating it with ultraviolet light of 1000 kJ / cm² for 30 seconds, and then heated at 120°C for 60 minutes to obtain a film for measuring moisture permeability. A cup for measuring moisture permeability was prepared according to the method for testing moisture permeability of moisture-proof packaging materials (cup method) of JIS Z 0208, and the obtained film for measuring moisture permeability was attached to the cup. The cup was then placed in a constant temperature and humidity oven at 80°C and 90% RH to measure the moisture permeability. The moisture permeability was evaluated according to the following criteria: ⊚: Moisture permeability of 60 g / m² ２ ・24 hours or less ○: Moisture permeability is 60 g / m ２ ・Over 24 hours 70g / m ２ If it was 24 hours or less, △: Moisture permeability was 70 g / m ２ ・Over 24 hours 80g / m ２ If it was 24 hours or less, ×: Moisture permeability was 80 g / m ２ ・If it exceeds 24 hours

[0051] (Coating Property) The obtained sealant for a light control element was applied to one of two glass substrates with an ITO thin film using a dispenser so as to draw a square frame to form a seal pattern, and then the other substrate was placed on top of the glass substrate in a vacuum. After the vacuum was released, the seal pattern was irradiated with 100 mW / cm irradiated with a metal halide lamp. ２After irradiating the test piece with ultraviolet light for 30 seconds, the test piece was heated at 120°C for 60 minutes to obtain a test piece. The seal pattern portion in the test piece obtained was visually observed, and the coating property was evaluated according to the following criteria: ⊚: When the seal pattern had a clean line without any disconnection or undulations; ∘: When there was no disconnection but the seal pattern had undulations; ×: When there was disconnection

[0052] (Low contamination) The obtained sealant for light control devices was applied to one of two glass substrates with an ITO thin film using a dispenser in a circular frame pattern to form an outer frame seal pattern. The sealant for light control devices was applied in dots inside the formed seal pattern. Subsequently, a γ-butyrolactone solution containing 30% by mass of ethyl 2-cyano-3,3-diphenylacrylate as an electrochromic compound was applied dropwise to the entire inside the frame of the sealant on the glass substrate with the ITO thin film, and the other substrate was then placed on top of it in a vacuum. After releasing the vacuum, a metal halide lamp was used to illuminate the outer frame seal pattern at 100 mW / cm. ２ Test pieces were obtained by irradiating the test pieces with ultraviolet light for 30 seconds, followed by heating at 120°C for 60 minutes. During the ultraviolet light irradiation, a mask was used to prevent the dotted sealant for light control devices from being irradiated with ultraviolet light. A voltage of 1.0 V was applied to the test pieces obtained for 5 minutes, and the display unevenness and contamination distance around the dotted sealant for light control devices were checked, and the low contamination was evaluated according to the following criteria: 1: No display unevenness occurred 2: Display unevenness occurred and the contamination distance was 25 μm or less 3: The contamination distance was more than 25 μm and 50 μm or less 4: The contamination distance was more than 50 μm and 100 μm or less 5: The contamination distance was more than 100 μm and 200 μm or less

[0053]

[0054]

[0055]

[0056] According to the present invention, it is possible to provide a sealant for a light control device that has excellent adhesiveness and low contamination.

Claims

1. A sealant for light control elements comprising a curable resin, a photoradical polymerization initiator, and an amine-based heat curing agent, wherein the curable resin contains a (meth)acrylic compound having no epoxy groups, the (meth)acrylic compound contains a compound having two or more (meth)acryloyl groups in one molecule, and the curable resin does not contain an epoxy compound or contains 5 parts by mass or less of an epoxy compound per 100 parts by mass of the curable resin.

2. The sealant for light control devices according to claim 1, wherein the curable resin does not contain an epoxy compound.

3. A sealant for light control elements according to claim 1 or 2, wherein the content of said amine-based heat curing agent relative to 100 parts by mass of said curable resin is 0.5 parts by mass or more and 3.0 parts by mass or less.

4. A sealant for light control elements according to claim 1, 2 or 3, in which the content of the amine-based heat curing agent is 0.5 parts by mass or more and 3.0 parts by mass or less per 100 parts by mass of the compound having two or more (meth)acryloyl groups in one molecule.

5. A sealant for light control devices according to claim 1, 2, 3 or 4, wherein the amine-based heat curing agent contains a hydrazide compound.

6. The sealant for light-adjusting elements according to claim 1, 2, 3, 4 or 5, which is used to seal an electrochromic element.

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