Light-curing adhesive

Abstract

To provide a photocurable adhesive which can reduce a release amount of gas from a cured material.SOLUTION: A photocurable adhesive 1 is configured to be curable by irradiation of laser light. The photocurable adhesive 1 comprises: an epoxy-based adhesive component 11; and a light-absorbing component 12 which is configured to be capable of generating heat by irradiation of laser light. The epoxy-based adhesive component 11 comprises a cyanate ester resin (A), an epoxy resin (B), an amine-based latent curing agent (C) having an active hydrogen, and an ion scavenger (D).SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a light-curable adhesive. [Background technology]

[0002] Photocurable adhesives that can be cured by irradiation with light are used in various fields, taking advantage of the characteristic that the time required for curing is relatively short. For example, Patent Document 1 describes a rapid photocurable epoxy adhesive composition that contains an epoxy adhesive component and a light absorbing component that can heat-cure the epoxy adhesive by absorbing laser light. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2010-180352 A Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, adhesives are sometimes used to bond components of optical devices such as in-vehicle camera modules, LiDAR (i.e., Light Detection and Ranging) modules, and head-up displays. However, in the adhesive composition of Patent Document 1, gas may be generated from the cured product of the adhesive and remain inside the optical device. If this gas sublimes and precipitates inside the optical device, it may cause fluctuations in the optical properties, such as the reflectance and transmittance, of the components.

[0005] The present invention has been made in view of the above problems, and aims to provide a photocurable adhesive that can reduce the amount of gas released from the cured product. [Means for solving the problem]

[0006] One aspect of the present invention is a photocurable adhesive (1) configured to be cured by irradiation with laser light, An epoxy adhesive component (11); a light absorbing component (12) configured to generate heat when irradiated with the laser light, The epoxy adhesive component (11) is A cyanate ester resin (A); An epoxy resin (B); (C) an amine-based latent curing agent having active hydrogen; An ion scavenger (D), And, the content of the ion scavenger (D) is 1.9 parts by mass or more and 5 parts by mass or less per 100 parts by mass in total of the cyanate ester resin (A), the epoxy resin (B), and the amine-based latent curing agent (C); It is found in light-curing adhesives. Effect of the Invention

[0007] The epoxy adhesive component (11) of the photocurable adhesive (1) contains an ion trapping agent (D) in addition to the cyanate ester resin (A), epoxy resin (B), and amine-based latent curing agent (C) for developing adhesive properties. By blending the ion trapping agent (D) in the epoxy adhesive component in this way, ionic volatile components and volatile organic acids generated in the cured product of the photocurable adhesive can be trapped by the ion trapping agent (D). As a result, the amount of gas released from the cured product to the outside can be reduced.

[0008] As described above, according to the above aspect, it is possible to provide a photocurable adhesive (1) that can reduce the amount of gas released from the cured product. In addition, the symbols in parentheses described in the claims and the means for solving the problems indicate a correspondence with the specific means described in the embodiments described below, and do not limit the technical scope of the present invention. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is an explanatory diagram showing a schematic diagram of a photocurable adhesive according to the first embodiment. [Diagram 2]FIG. 2 is a cross-sectional view showing a main part of a lens module to which a light-curing adhesive is applied in the second embodiment. [Diagram 3] FIG. 3 is an explanatory diagram illustrating a schematic view of a main part of a LiDAR module to which a photocurable adhesive is applied in the second embodiment. [Figure 4] FIG. 4 is an explanatory diagram illustrating a schematic view of a main part of a head-up display to which a photocurable adhesive is applied in the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] (Embodiment 1) An embodiment of the photocurable adhesive will be described with reference to FIG. 1. The photocurable adhesive 1 of this embodiment is configured to be curable by irradiation with laser light. The wavelength of the laser light irradiated to the photocurable adhesive 1 may be a wavelength corresponding to the absorption wavelength of the light absorbing component. The laser light may be, for example, a near-infrared laser having a wavelength of 780 nm to 3 μm. The photocurable adhesive 1 includes an epoxy adhesive component 11 and a light absorbing component 12 configured to be able to generate heat by irradiation with laser light. The configuration of the photocurable adhesive 1 will be described in more detail below.

[0011] 1. Epoxy adhesive components The epoxy adhesive component 11 in the photocurable adhesive 1 is configured so that when irradiated with laser light, it can be cured by heat generation from the light absorbing component 12. The epoxy adhesive component 11 contains a cyanate ester resin (A), an epoxy resin (B), an amine-based latent curing agent (C), and an ion trapping agent (D).

[0012] 1-1. Cyanate ester resin (A) As the cyanate ester resin (A), a compound having two or more cyanato groups (-O-CN) in one molecule can be used. The cyanate ester resin (A) may be, for example, at least one compound selected from the group consisting of a compound (A-1) represented by the following general formula (1), a compound (A-2) represented by the following general formula (2), and a polymer (A-3) of one or more compounds selected from the compounds (A-1) to (A-2).

[0013] [ka]

[0014] However, A in the general formula (1) 1 and A 2 each independently represents an unsubstituted phenylene group or a phenylene group substituted with an alkyl group having 1 to 4 carbon atoms; Y 1 represents an ether bond, a thioether bond, or a divalent hydrocarbon group which may have a substituent.

[0015] [ka]

[0016] In the general formula (2), m is an integer of 1 or more, and R 1 ~R 6 each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; Y 2 and Y 3 each independently represents a divalent hydrocarbon group or a fluorine-substituted divalent alkylene group.

[0017] Y in the general formula (1) 1 Y in the general formula (2) 2 and Y 3 may be, for example, a divalent hydrocarbon group represented by the following structural formulas (3) to (11).

[0018] [ka]

[0019] [ka]

[0020] [ka]

[0021] [ka]

[0022] [ka]

[0023] [ka]

[0024] [ka]

[0025] [ka]

[0026] [ka]

[0027] In the structural formulas (3) to (11), * represents a bond. 7 and R 8 each independently represents a hydrogen atom, an unsubstituted methyl group, or a fluorine-substituted methyl group. In the structural formula (11), n ​​is an integer of 4 or more and 12 or less.

[0028] More specifically, the cyanate ester resin (A) is particularly preferably a bisphenol type cyanate ester resin.

[0029] 1-2.Epoxy resin (B) As the epoxy resin (B), a compound having two or more epoxy groups in one molecule can be used. The epoxy resin (B) may be composed of only one type of compound having an epoxy group, or may be composed of two or more types of compounds having an epoxy group.

[0030] The content of the epoxy resin (B) in the photocurable adhesive 1 can be appropriately set within the range of, for example, 1 part by mass or more and 10,000 parts by mass or less per 100 parts by mass of the cyanate ester resin (A). By setting the content of the epoxy resin (B) to 1 part by mass or more per 100 parts by mass of the cyanate ester resin (A), the photocurable adhesive 1 can be sufficiently cured when irradiated with laser light. From the viewpoint of further improving the curability of the photocurable adhesive 1, the content of the epoxy resin (B) is preferably 10 parts by mass or more, more preferably 20 parts by mass or more, per 100 parts by mass of the cyanate ester resin (A).

[0031] In addition, by setting the content of the epoxy resin (B) to 10,000 parts by mass or less per 100 parts by mass of the cyanate ester resin (A), a cured product having excellent physical properties can be obtained. From the viewpoint of further improving the physical properties of the cured product, the content of the epoxy resin (B) is preferably 1,000 parts by mass or less, more preferably 500 parts by mass or less, per 100 parts by mass of the cyanate ester resin (A).

[0032] The epoxy resin (B) is, for example, a polyglycidyl ether compound of a mononuclear polyhydric phenol compound such as hydroquinone, resorcinol, pyrocatechol, or phloroglucinol; or a polynuclear polyhydric phenol such as dihydroxynaphthalene, biphenol, methylene bisphenol (bisphenol F), methylene bis(ortho-cresol), ethylidene bisphenol, isopropylidene bisphenol (bisphenol A), isopropylidene bis(ortho-cresol), tetrabromobisphenol A, 1,3-bis(4-hydroxycumylbenzene), 1,4-bis(4-hydroxycumylbenzene), 1,1,3-tris(4-hydroxyphenyl)butane, 1,1,2,2-tetra(4-hydroxyphenyl)ethane, thiobisphenol, sulfobisphenol, oxybisphenol, phenol novolac, orthocresol novolac, ethylphenol novolac, butylphenol novolac, octylphenol novolac, resorcinol novolac, or terpene phenol. Polyglycidyl ether compounds of compounds; polyglycidyl ethers of polyhydric alcohols such as ethylene glycol, propylene glycol, butylene glycol, hexanediol, polyglycol, thiodiglycol, glycerin, trimethylolpropane, pentaerythritol, sorbitol, and bisphenol A-ethylene oxide adduct; maleic acid, fumaric acid, itaconic acid, succinic acid, glutaric acid, suberic acid, adipic acid, azelaic acid, sebacic acid, dimer acid, trimer acid, Glycidyl esters of aliphatic, aromatic or alicyclic polybasic acids, such as phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, trimesic acid, pyromellitic acid, tetrahydrophthalic acid, hexahydrophthalic acid, and endomethylenetetrahydrophthalic acid; homopolymers or copolymers of glycidyl methacrylate; epoxy compounds having a glycidylamino group, such as N,N-diglycidylaniline, bis(4-(N-methyl-N-glycidylamino)phenyl)methane, and diglycidyl orthotoluidine;The epoxy compound may be an epoxy compound of a cyclic olefin compound such as vinylcyclohexene diepoxide, dicyclopentadiene diepoxide, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexane carboxylate, 3,4-epoxy-6-methylcyclohexylmethyl-6-methylcyclohexane carboxylate, or bis(3,4-epoxy-6-methylcyclohexylmethyl) adipate; an epoxy compound of a conjugated diene polymer such as an epoxy polybutadiene or an epoxy styrene-butadiene copolymer; or a heterocyclic compound such as triglycidyl isocyanurate. These compounds may be internally crosslinked with a prepolymer of a terminal isocyanate, or may be polymerized with a polyvalent active hydrogen compound (polyhydric phenol, polyamine, carbonyl group-containing compound, polyphosphate ester, etc.);

[0033] From the viewpoint of reactivity, the epoxy resin (B) preferably contains a glycidyl type epoxy resin having a glycidyl group, and more preferably contains one or more compounds selected from the group consisting of a polyglycidyl ether compound of a polynuclear polyhydric phenol compound, an epoxy compound having a glycidyl amino group, and a polyglycidyl ether compound of dicyclopentadiene dimethanol. When the epoxy resin (B) contains a polyglycidyl ether compound of a polynuclear polyhydric phenol compound, the heat resistance of the cured product can be further improved. When the epoxy resin (B) contains an epoxy compound having a glycidyl amino group, the reactivity of the photocurable adhesive 1 can be further improved and the heat resistance of the cured product can be further improved. When the epoxy resin (B) contains a polyglycidyl ether compound of dicyclopentadiene dimethanol, the photocurable adhesive 1 can be provided with adhesion.

[0034] 1-3. Amine-based latent hardener (C) As the amine-based latent curing agent (C), for example, a compound having active hydrogen derived from an amino group or a mixture containing the compound can be used. The content of the amine-based latent curing agent (C) can be appropriately set, for example, within the range of 1 part by mass or more and 100 parts by mass or less per 100 parts by mass of the total amount of the cyanate ester resin (A) and the epoxy resin (B). The content of the amine-based latent curing agent (C) is preferably 5 to 60 parts by mass per 100 parts by mass of the total amount of the cyanate ester resin (A) and the epoxy resin (B).

[0035] The amine-based latent curing agent (C) may be, for example, a modified amine (C-1) obtained by reacting an amine compound having one or more active hydrogens in one molecule with an epoxy compound. The amine-based latent curing agent (C) may be composed of one type of modified amine (C-1), or may be composed of two or more types of modified amines (C-1).

[0036] The modified amine (C-1) has an amine structural unit derived from the amine compound and an epoxy structural unit derived from the epoxy compound, and has a structure in which the amine structural unit and the epoxy structural unit are bonded together. Examples of the amine compound used in the modified amine (C-1) include diamines having two primary and / or secondary amino groups in the molecule, and polyamines having two or more primary and / or secondary amino groups in the molecule. These amine compounds may be used alone, or two or more amine compounds may be used in combination.

[0037] More specifically, examples of the amine compounds used in the modified amine (C-1) include aliphatic diamines and polyamines such as ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, polyoxypropylenediamine, and polyoxypropylenetriamine; isophoronediamine, menthenediamine, bis(4-amino-3-methyldicyclohexyl)methane, diaminodicyclohexylmethane, bis(aminomethyl)cyclohexane, N-aminoethylpiperazine, and 3,9-bis(3-aminopropyl)-2,4,8,10-tetraoxaspiro(5.5)undecane. Alicyclic diamines and polyamines; mononuclear diamines and polyamines such as m-phenylenediamine, p-phenylenediamine, tolylene-2,4-diamine, tolylene-2,6-diamine, mesitylene-2,4-diamine, mesitylene-2,6-diamine, 3,5-diethyltolylene-2,4-diamine, and 3,5-diethyltolylene-2,6-diamine; aromatic diamines and polyamines such as biphenylenediamine, 4,4-diaminodiphenylmethane, 2,5-naphthylenediamine, and 2,6-naphthylenediamine; imidazole compounds having amino groups such as 2-aminopropylimidazole. In addition, as the amine compound used in the modified amine (C-1), an epoxy modified amine obtained by reacting the above-mentioned compound with an epoxy compound can also be used. These amine compounds may be used alone, or two or more amine compounds may be used in combination.

[0038] The modified amine (C-1) preferably has a structural unit derived from one or more amine compounds selected from the group consisting of diamines having two primary and / or secondary amino groups with different reactivity in the molecule, and polyamines having two or more primary and / or secondary amino groups in the molecule, in which when one of the groups reacts with an epoxy group, the reactivity of the remaining primary and / or secondary amino groups with the epoxy group decreases due to steric hindrance. The modified amine (C-1) obtained by using these amine compounds can improve the adhesiveness of the photocurable adhesive 1 and the physical properties of the cured product. The diamines mentioned above include aliphatic diamines, alicyclic diamines, and aromatic diamines. The polyamines mentioned above include aliphatic polyamines, alicyclic polyamines, and aromatic polyamines.

[0039] Examples of such diamines include isophoronediamine, menthanediamine, 2,2,4-trimethylhexamethylenediamine, 2,4,4-trimethylhexamethylenediamine, 1,2-diaminopropane, m-xylylenediamine, 1,3-bisaminocyclohexane, and N-aminoethylpiperazine.

[0040] As the amine compound, an imidazole compound containing a primary amino group such as 2-aminopropylimidazole can also be used. The modified amine (C-1) obtained using such an imidazole compound further improves the low-temperature curing property of the photocurable adhesive 1, and allows the photocurable adhesive 1 to be cured more easily even at low temperatures.

[0041] The epoxy compound used in the modified amine (C-1) may have one or more epoxy groups in one molecule.

[0042] More specifically, examples of epoxy compounds used in the modified amine (C-1) include monoglycidyl ether compounds such as phenyl glycidyl ether, allyl glycidyl ether, methyl glycidyl ether, butyl glycidyl ether, secondary butyl glycidyl ether, 2-ethylhexyl glycidyl ether, 2-methyloctyl glycidyl ether, and stearyl glycidyl ether; monoglycidyl ester compounds such as versatic acid glycidyl ester; mononuclear glycidyl ether compounds such as hydroquinone, resorcinol, pyrocatechol, and phloroglucinol; Polyglycidyl ether compounds of polyhydric phenol compounds; dihydroxynaphthalene, biphenol, methylene bisphenol (i.e., bisphenol F), methylene bis(ortho-cresol), ethylidene bisphenol, isopropylidene bisphenol (i.e., bisphenol A), isopropylidene bis(ortho-cresol), tetrabromobisphenol A, 1,3-bis(4-hydroxycumylbenzene), 1,4-bis(4-hydroxycumylbenzene), 1,1,3-tris(4-hydroxyphenyl)butane, 1,1,2 Polyglycidyl ether compounds of polynuclear polyhydric phenol compounds such as 2-tetra(4-hydroxyphenyl)ethane, thiobisphenol, sulfobisphenol, oxybisphenol, phenol novolac, orthocresol novolac, ethylphenol novolac, butylphenol novolac, octylphenol novolac, resorcinol novolac, and terpene phenol; ethylene glycol, propylene glycol, butylene glycol, hexanediol, polyglycol, thiodiglycol, glycerin, and trimethylol. Polyglycidyl ethers of polyhydric alcohols such as propane, pentaerythritol, sorbitol, and bisphenol A-ethylene oxide adducts; glycidyl esters of aliphatic, aromatic, or alicyclic polybasic acids such as maleic acid, fumaric acid, itaconic acid, succinic acid, glutaric acid, suberic acid, adipic acid, azelaic acid, sebacic acid, dimer acid, trimer acid, phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, trimesic acid, pyromellitic acid, tetrahydrophthalic acid, hexahydrophthalic acid, and endomethylenetetrahydrophthalic acid;Examples of the epoxy compounds include homopolymers or copolymers of glycidyl methacrylate; epoxy compounds having a glycidyl amino group, such as N,N-diglycidylaniline, bis(4-(N-methyl-N-glycidylamino)phenyl)methane, and diglycidyl orthotoluidine; epoxidized products of cyclic olefin compounds, such as vinylcyclohexene diepoxide, dicyclopentadiene diepoxide, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, 3,4-epoxy-6-methylcyclohexylmethyl-6-methylcyclohexanecarboxylate, and bis(3,4-epoxy-6-methylcyclohexylmethyl)adipate; epoxidized conjugated diene polymers, such as epoxidized polybutadiene and epoxidized styrene-butadiene copolymer; and heterocyclic compounds, such as triglycidyl isocyanurate. These epoxy compounds may be used alone, or two or more kinds of epoxy compounds may be used in combination.

[0043] The epoxy compound used in the modified amine (C-1) is preferably a polyglycidyl ether compound having two or more epoxy groups in the molecule, and is particularly preferably a polyglycidyl ether of a bisphenol compound such as methylene bisphenol (i.e., bisphenol F), methylene bis(ortho-cresol), ethylidene bisphenol, isopropylidene bisphenol (i.e., bisphenol A), or isopropylidene bis(ortho-cresol).

[0044] In preparing the modified amine (C-1), the amine compound and the epoxy compound may be reacted so that primary and / or secondary amino groups remain after the reaction. For example, when an amine compound having a total of two or more primary and / or secondary amino groups in one molecule is reacted with an epoxy compound, the epoxy compound is preferably reacted in an amount such that the epoxy equivalent is 0.5 to 2 equivalents, more preferably 0.8 to 1.5 equivalents, relative to the amount of 1 mole of the amine compound.

[0045] The amine-based latent curing agent (C) may be a mixture (C-2) of the modified amine (C-1) and a phenolic resin. The mixture (C-2) may contain one type of modified amine (C-1), or may contain two or more types of modified amine (C-1). Similarly, the mixture (C-2) may contain one type of phenolic resin, or may contain two or more types of phenolic resin. By using the mixture (C-2) as the amine-based latent curing agent (C), the storage stability of the photocurable adhesive 1 can be further improved.

[0046] The phenolic resin used in combination with the modified amine (C-1) is, for example, a resin obtained by polycondensation of phenols and aldehydes. Examples of phenols include phenol, cresol, ethylphenol, n-propylphenol, isopropylphenol, butylphenol, tertiary butylphenol, octylphenol, nonylphenol, dodecylphenol, cyclohexylphenol, chlorophenol, bromophenol, resorcinol, catechol, hydroquinone, 2,2-bis(4-hydroxyphenyl)propane, 4,4'-thiodiphenol, dihydroxydiphenylmethane, naphthol, terpenephenol, and phenolized dicyclopentadiene. Examples of aldehydes include formaldehyde.

[0047] The content of the phenol resin in the mixture (C-2) of the modified amine (C-1) and the phenol resin can be appropriately set, for example, in the range of 10 parts by mass or more and 100 parts by mass or less per 100 parts by mass of the modified amine (C-1).

[0048] 1-4. Ion scavenger (D) The ion trapping agent (D) has the function of trapping ionic volatile components and volatile organic acids generated in the cured product of the photocurable adhesive 1. The ionic volatile components and volatile organic acids generated in the cured product are derived from decomposition products derived from, for example, glass contained in the components of the photocurable adhesive 1 or the members to be bonded. The ion trapping agent (D) may be an organic or inorganic substance as long as it has the above-mentioned function. From the viewpoint of heat resistance, the ion trapping agent (D) is preferably an inorganic substance. In addition, the photocurable adhesive 1 may contain one type of ion trapping agent (D) or two or more types of ion trapping agents (D).

[0049] The content of the ion scavenger (D) is, for example, 100 parts by mass of the total of the cyanate ester resin (A), the epoxy resin (B), and the amine-based latent curing agent (C). 1.9 The amount can be appropriately set within the range of not less than 5 parts by mass.

[0050] The ion trapping agent (D) preferably has an ion exchange capacity of 1.0 meq / g or more. By using such an ion trapping agent (D), it is possible to trap more ionic volatile components and further reduce the amount of gas released from the cured product of the photocurable adhesive 1 to the outside. In addition, the photocurable adhesive 1 containing such an ion trapping agent (D) has excellent anti-fogging properties in a high-temperature and high-humidity environment, and when used in an optical device, it is possible to suppress the deterioration of the optical properties of the optical element for a longer period of time.

[0051] The ion exchange capacity of the ion trapping agent (D) can be measured, for example, by the method described in WO2008 / 053694. Specifically, first, a sodium hydroxide aqueous solution with a concentration of 0.1 mol / L is prepared, and the measurement specimen and 50 mL of the sodium hydroxide aqueous solution are placed in a 100 mL polyethylene container. After shaking the container at 40° C. for 20 hours, the supernatant is collected from the container. Separately, a blank is collected from the contents of the container by performing the same operation as above except that the measurement specimen is not placed in the container. Then, the sodium ion concentration of the supernatant and the sodium ion concentration of the blank are measured by inductively coupled plasma atomic emission spectrometry (i.e., ICP). The sodium ion concentration of the supernatant is subtracted from the sodium ion concentration of the blank thus obtained to obtain the equivalent of sodium ions held in the specimen. Then, the value obtained by dividing the equivalent of sodium ions by the weight of the specimen is taken as the ion exchange capacity of the ion trapping agent (D). The ion exchange capacity of the ion trapping agent (D) is usually 10 meq / g or less.

[0052] The ion scavenger (D) is preferably inorganic fine particles, which have excellent heat resistance and are easily dispersed uniformly in the photocurable adhesive 1.

[0053] The ion trapping agent (D) preferably contains one or more metal atoms selected from the group consisting of Zr (zirconium) atoms, Sb (antimony) atoms, Bi (bismuth) atoms, Y (yttrium) atoms, Al (aluminum) atoms, Mg (magnesium) atoms, La (lanthanum) atoms, and Nd (neodymium) atoms. In this case, the trapping ability of ionic volatile components in a high-temperature and high-humidity environment can be further improved.

[0054] The ion trapping agent (D) containing the above-mentioned metal atom may be a single metal or a metal compound. Examples of such an ion trapping agent (D) include zirconium phosphate, zirconium tungstate, zirconium molybdate, zirconium antimonate, zirconium selenate, zirconium tellurate, zirconium silicate, zirconium phosphosilicate, zirconium polyphosphate, bismuth oxide compounds, bismuth hydroxide compounds, yttrium oxide, lanthanum oxide, neodymium oxide, composite oxides of magnesium and aluminum, hydrotalcite, hydrocalumite, hydroohmite, zeolite, and other composite metal oxides. These substances may be natural or artificial.

[0055] In addition, examples of the ion scavenger (D) that can be used include commercially available products such as "IXE-100", "IXE-300", "IXE-500", "IXE-530", "IXE-550", "IXE-600", "IXE-633", "IXE-700F", "IXE-770D", "IXE-800", "IXE-1000", "IXE-6107", "IXE-6136", "IXEPLAS-A1", "IXEPLAS-A2", and "IXEPLAS-B1" manufactured by Toagosei Co., Ltd., and "Kyoward 200", "Kyoward 500", "Kyoward 600", "Kyoward 700", "KW-2000", and "DHT-4A" manufactured by Kyowa Chemical Industry Co., Ltd.

[0056] "IXE" and "IXEPLAS" are registered trademarks of Toagosei Co., Ltd., and "Kyoward" and "DHT-4A" are registered trademarks of Kyowa Chemical Industry Co., Ltd.

[0057] From the viewpoint of further improving the ability to capture ionic volatile components in a high-temperature and high-humidity environment, the ion scavenger (D) is more preferably a metal compound.

[0058] The ion trapping agent (D) preferably has a particle size distribution in which the median diameter in the volumetric particle size distribution is 0.001 μm or more and 100 μm or less, and more preferably has a particle size distribution in which the median diameter is 0.01 μm or more and 20 μm or less. In this case, the trapping ability of ionic volatile components in a high-temperature and high-humidity environment can be further improved. The above-mentioned particle size distribution can be obtained, for example, by a laser diffraction / scattering method.

[0059] It is more preferable that the ion trapping agent (D) contains Zr atoms, Al atoms, and Mg atoms. The photocurable adhesive 1 containing such an ion trapping agent (D) can exhibit excellent anti-fogging properties when applied to an optical device. From this viewpoint, it is more preferable that the ion trapping agent (D) is an inorganic fine particle containing Zr atoms, Al atoms, and Mg atoms, and is particularly preferable that the ion trapping agent (D) is an inorganic fine particle containing Zr atoms, Al atoms, and Mg atoms and having a particle size distribution in which the median diameter in the volumetric particle size distribution is 0.01 μm or more and 10 μm or less, and is most preferable that the ion trapping agent (D) is an inorganic fine particle containing Zr atoms, Al atoms, and Mg atoms, not containing Bi atoms, and having a particle size distribution in which the median diameter in the volumetric particle size distribution is 0.01 μm or more and 10 μm or less. Examples of such an ion trapping agent (D) include "IXEPLAS-A1" and "IXEPLAS-A2" manufactured by Toagosei Co., Ltd.

[0060] 1-5. Filling material The epoxy adhesive component 11 may contain a filler 13 in addition to the essential components of the cyanate ester resin (A), the epoxy resin (B), the amine-based latent curing agent (C) and the ion scavenger (D). By blending the filler 13 in the epoxy adhesive component 11, the physical properties of the cured product of the photocurable adhesive 1 can be improved. As the filler 13, for example, inorganic fillers such as silica, alumina, aluminum nitride, glass, boron nitride, titanium dioxide, kaolin, clay, talc, carbon fiber, iron oxide and diamond can be used. The filler 13 is preferably translucent, and more preferably has a transmittance of 80% or more for infrared laser light with a wavelength of 800 nm to 1100 nm. In this case, the curability of the photocurable adhesive 1 can be improved.

[0061] 2. Light-absorbing components The light-curable adhesive 1 contains a light-absorbing component 12 that is configured to generate heat when absorbing laser light. The light-absorbing component 12 has the effect of heating and curing the epoxy adhesive component 11 by generating heat when irradiated with laser light. As the light-absorbing component 12, for example, light-absorbing substances such as carbon black, black metal-containing paint, azine-based paint, and nigrosine-based compounds can be used. As the nigrosine-based compounds, for example, water-insoluble nigrosine-based compounds such as nigrosine sulfate and phosphate can be used. The light-absorbing substance may be used alone or in combination of two or more substances. The light-absorbing component 12 is preferably made of carbon black. In this case, the curability of the light-curable adhesive 1 against laser light can be further improved.

[0062] The content of the light absorbing component 12 can be, for example, 0.1 mass % or less relative to the entire photocurable adhesive 1.

[0063] 3.Other Ingredients In addition to the epoxy adhesive component 11 and the light absorbing component 12, the photocurable adhesive 1 may contain various additives used in adhesives.

[0064] For example, various solvents may be contained in the photocurable adhesive 1 to facilitate handling. As the solvent, it is preferable to use an organic solvent. More specifically, ethers such as tetrahydrofuran, 1,2-dimethoxyethane, and 1,2-diethoxyethane, alcohols such as iso- or n-butanol, iso- or n-propanol, amyl alcohol, benzyl alcohol, furfuryl alcohol, and tetrahydrofurfuryl alcohol, ketones such as methyl ethyl ketone, methyl isopropyl ketone, and methyl butyl ketone, aromatic hydrocarbons such as benzene, toluene, and xylene, triethylamine, pyridine, dioxane, and acetonitrile can be used as the solvent.

[0065] (Embodiment 2) In this embodiment, examples will be described in which the photocurable adhesive 1 of the first embodiment is applied to various optical devices 2. Note that, among the symbols used in this and subsequent embodiments, the same symbols as those used in the previous embodiments represent the same components, etc. as those in the previous embodiments, unless otherwise specified.

[0066] The photocurable adhesive 1 of the first embodiment can be applied to various optical devices 2. The optical device 2 may be, for example, a lens module 21 as shown in FIG. 2. The lens module 21 of FIG. 2 has a circuit board 211, a lens holder 212 provided on the circuit board 211, one or more lenses 213 held by the lens holder 212, and an image sensor 214 held on the optical path L of the lens 213 on the circuit board 211. These components are bonded together via a cured product 10 of the photocurable adhesive 1. The lens holder 212 may hold an optical filter instead of the lens 213.

[0067] The optical device 2 may be, for example, a LiDAR module 22 as shown in FIG. 3. The LiDAR module 22 in FIG. 3 includes a circuit board 221, a light source 222 held by the circuit board 221, one or more reflectors 223 arranged on an optical path L of light generated from the light source 222, and a fixing base 224 that holds the reflector 223. Between the circuit board 221 and the light source 222, and between the reflector 223 and the fixing base 224, a cured product 10 of the photocurable adhesive 1 is interposed, and these components are joined via the cured product 10 of the photocurable adhesive 1. As the light source 222, for example, a laser diode or the like can be used.

[0068] The optical device 2 may be, for example, a head-up display 23 as shown in Fig. 4. The head-up display 23 in Fig. 4 has a circuit board 231, a light source 232 held by the circuit board 231, a magnifying mirror 233 arranged on an optical path L of light generated from the light source 232, a stay 234 holding the magnifying mirror 233, and a screen 235 arranged on an optical path L of light reflected by the magnifying mirror 233. A cured product 10 of the photocurable adhesive 1 is interposed between the circuit board 231 and the light source 232, and between the magnifying mirror 233 and the stay 234, and these components are joined via the cured product 10 of the photocurable adhesive 1.

[0069] By applying the photocurable adhesive 1 of the first embodiment to the various optical devices 2 described above, it is possible to reduce the amount of gas released from the cured product 10 of the photocurable adhesive 1 to the outside. As a result, it is possible to prevent the gas released from the cured product 10 from sublimating into optical elements such as the lens 213, the image sensor 214, the optical filter, the reflector 223, and the magnifying mirror 233. As a result, it is possible to prevent a decrease in the transmittance, reflectance, etc. of the optical elements over a long period of time.

[0070] (Experimental Example) In this example, a more specific example of the configuration of the photocurable adhesive 1 according to the first embodiment will be described. In this example, first, a photocurable adhesive 1 (test agent S1, test agent S2) was prepared, which contains a cyanate ester resin (A), an epoxy resin (B), an amine-based latent curing agent (C), an ion trapping agent (D), a light absorbing component 12, and a filler 13 in the mass ratio shown in Table 1. The cyanate ester resin (A), the epoxy resin (B), the amine-based latent curing agent (C), the ion trapping agent (D), the light absorbing component 12, and the filler 13 used in this example are specifically as follows:

[0071] Cyanate ester resin (A) CY-1: Bisphenol-type cyanate ester resin ("Lecy" manufactured by Lonza)

[0072] Epoxy resin (B) EP-1: Bisphenol A type epoxy resin (ADEKA Corporation "ADEKA Resin EP-4300E") EP-2: Glycidylamine type epoxy resin (ADEKA Corporation "ADEKA Resin EP-3950S") EP-3: Dicyclopentadiene type epoxy resin (ADEKA Corporation "ADEKA Resin EP-4088S") "ADEKA RESIN" is a registered trademark of ADEKA Corporation.

[0073] Amine-based latent hardener (C) EH-1: A mixture of modified amine (C-1) and phenolic resin (C-2) prepared by the following method

[0074] First, 201 g (i.e., 2.71 moles) of 1,2-diaminopropane was placed in a flask and then heated to 60°C. Next, 580 g of bisphenol A type epoxy resin (ADEKA Corporation's "ADEKA RESIN EP-4100E", epoxy equivalent 190) was gradually added to the flask while maintaining the temperature in the system at 100 to 110°C. When 1,2-diaminopropane and bisphenol A type epoxy resin are mixed as described above, the epoxy equivalent of the bisphenol A type epoxy resin relative to 1 mole of 1,2-diaminopropane is 1.12.

[0075] After the addition of the bisphenol A type epoxy resin was completed, the temperature in the reaction system was raised to 140° C., and this temperature was maintained for 1.5 hours to react the contents. As a result, a modified amine (C-1) was obtained.

[0076] Next, 100 g of the modified amine (C-1) obtained by the above method was mixed with 30 g of phenolic resin ("MP-800K" manufactured by Asahi Organic Chemicals Co., Ltd., softening point 100°C), and the mixture was then held at a temperature of 180-190°C for 1 hour under a reduced pressure environment of 30-40 Torr to perform degassing under reduced pressure. This removed unreacted materials from the mixture. The mixture was then pulverized with a jet mill. As a result, EH-1 was obtained.

[0077] Ion trapping agent (D) IC-1: Inorganic fine particles containing Mg, Al, and Zr ("IXEPLAS-A1" manufactured by Toagosei Co., Ltd., median diameter 0.5 μm, sodium ion exchange capacity 1 meq / g to 10 meq / g)

[0078] Light absorbing component 12 P-1: Titanium black (Mitsubishi Materials Electronics Co., Ltd. "13M-C", primary particle size 97 nm) P-2: Carbon black (Mitsubishi Carbon Black Co., Ltd. "#750B", primary particle diameter 22 nm)

[0079] ·Filling material 13 Silica ("200SX-E1" manufactured by Admatechs Co., Ltd.)

[0080] In this example, test agents S3 and S4 were prepared for comparison with test agents S1 and S2. Test agents S3 and S4 have the same composition as test agents S1 and S2, except that the composition of each component was changed as shown in Table 1.

[0081] Next, the laser curability and anti-fogging properties of the test agents S1 to S4 were evaluated by the following method.

[0082] Laser hardenability 0.1g of the test agent was spread thinly on the bottom surface of a glass petri dish made of ordinary glass with dimensions of 75mm outer diameter and 20mm height. Next, the test agent was irradiated with near-infrared laser light having a wavelength of 915nm at an output of 3W for 5 seconds. After that, a spatula was brought into contact with the test agent in the petri dish to judge whether the test agent had hardened or not. If the test agent did not adhere to the spatula and was sufficiently hardened, the symbol "A" was entered in the "Laser hardening" column of Table 1. If the test agent adhered to the spatula or the test agent in contact with the spatula was deformed, the test agent was judged to have not hardened sufficiently, and the symbol "B" was entered in the same column.

[0083] Anti-fog The test agent was applied to the inside of a glass petri dish in the same manner as in the evaluation of laser hardening described above, and then the test agent was irradiated with laser light. The glass petri dish was then heated in an oven set at 120°C for 1 hour to allow the test agent in the dish to harden sufficiently.

[0084] Next, the petri dish on which the cured product of the test agent was placed was covered with a lid so that a gap of about 500 μm was formed. The glass petri dish was left to stand in a thermostatic chamber at a temperature of 85° C. and a relative humidity of 85% RH. When the total retention time in the thermostatic chamber reached 500 hours, 1000 hours, and 2000 hours, the glass petri dish was removed from the thermostatic chamber, and the glass surface around the cured product was observed using an optical microscope. The antifogging property was evaluated based on the time until the glass surface became cloudy.

[0085] The symbols in the "Anti-fogging property" column in Table 1 have the following meanings: A: Almost no clouding occurs on the glass surface after 2000 hours of retention time. B: The glass surface was almost cloudy until the retention time reached 1000 hours, and then cloudy at 2000 hours. C: The glass surface was almost cloudy until the retention time reached 500 hours, and then cloudy at 1000 hours. D: When the holding time reached 500 hours, the glass surface became cloudy.

[0086] [Table 1]

[0087] As shown in Table 1, the epoxy adhesive component 11 of test agents S1 and S2 contains an ion scavenger (D). Therefore, these test agents can be cured by irradiation with laser light. In addition, these test agents were able to suppress adhesion of precipitates to glass petri dishes even when left to stand in an environment with a temperature of 85°C and a relative humidity of 85%RH.

[0088] On the other hand, test agents S3 and S4 do not contain the ion scavenger (D), and therefore, when left to stand in an environment of 85°C temperature and 85% RH, these test agents were inferior in anti-fogging properties to test agents S1 and S2, and precipitates quickly formed on the glass petri dish.

[0089] The present invention is not limited to the above-described embodiments and experimental examples, and can be applied to various embodiments without departing from the gist of the present invention. [Explanation of symbols]

[0090] 1. Light-curing adhesive 11 Epoxy adhesive components 12 Light-absorbing components

Claims

1. A photocurable adhesive (1) configured to be cured by irradiation with laser light, An epoxy adhesive component (11); a light absorbing component (12) configured to generate heat by irradiation with the laser light, The epoxy adhesive component (11) is A cyanate ester resin (A); An epoxy resin (B); an amine-based latent curing agent (C) having active hydrogen; and an ion scavenger (D), a content of the ion scavenger (D) being 1.9 parts by mass or more and 5 parts by mass or less per 100 parts by mass of the total of the cyanate ester resin (A), the epoxy resin (B), and the amine-based latent curing agent (C),

2. 2. The photocurable adhesive according to claim 1, wherein the ion exchange capacity of the ion scavenger (D) is 1.0 meq / g or more.

3. The photocurable adhesive according to claim 1 or 2, wherein the ion scavenger (D) is an inorganic fine particle.

4. The photocurable adhesive according to any one of claims 1 to 3, wherein the ion scavenger (D) contains one or more metal atoms selected from the group consisting of Zr atoms, Sb atoms, Bi atoms, Y atoms, Al atoms, Mg atoms, La atoms, and Nd atoms.

5. The light-curable adhesive according to claim 4 , wherein the ion scavenger (D) contains Zr atoms, Al atoms, and Mg atoms.

6. The photocurable adhesive according to any one of claims 1 to 5, wherein the amine-based latent curing agent (C) is at least one selected from the group consisting of modified amines (C-1) obtained by reacting an amine compound having one or more active hydrogens in one molecule with an epoxy compound, and mixtures (C-2) of the modified amines (C-1) and phenolic resins.

7. 7. The photocurable adhesive according to claim 6, wherein the amine-based latent curing agent (C) is a mixture (C-2) of the modified amine (C-1) and a phenolic resin.

8. The photocurable adhesive according to any one of claims 1 to 7, wherein the cyanate ester resin (A) is at least one selected from the group consisting of a compound (A-1) represented by the following general formula (1), a compound (A-2) represented by the following general formula (2), and a polymer (A-3) of one or more compounds selected from the compounds (A-1) to (A-2). 【Chemistry 1】 (However, A in the general formula (1) １ and A ２ each independently represents an unsubstituted phenylene group or a phenylene group substituted with an alkyl group having 1 to 4 carbon atoms; Y １ represents an ether bond, a thioether bond, or a divalent hydrocarbon group which may have a substituent. 【Chemistry 2】 (In the above general formula (2), m is an integer of 1 or more, and R １ ~R ６ each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; Y ２ and Y ３ each independently represents a divalent hydrocarbon group or a fluorine-substituted divalent alkylene group.

9. Y in the general formula (1) １ , Y in the general formula (2) ２ and Y ３ is at least one of the divalent hydrocarbon groups represented by the following structural formulas (3) to (11): 【Chemistry 3】 (In the structural formula (3), * represents a bond, and R ７ and R ８ each independently represents a hydrogen atom, an unsubstituted methyl group, or a fluorine-substituted methyl group. 【Chemistry 4】 (Note that * in the structural formula (4) represents a bond.) 【Chemistry 5】 (Note that * in the structural formula (5) represents a bond.) 【Chemistry 6】 (Note that * in the structural formula (6) represents a bond.) 【Chemistry 7】 (Note that * in the structural formula (7) represents a bond.) 【Chemistry 8】 (Note that * in the structural formula (8) represents a bond.) 【Chemistry 9】 (Note that * in the structural formula (9) represents a bond.) 【Chemistry 10】 (Note that * in the structural formula (10) represents a bond.) 【Chemistry 11】 (In the structural formula (11), n ​​is an integer of 4 or more and 12 or less, and * represents a bond.)

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