Curable composition and its cured product

Abstract

This curable composition contains the following components (A) and (B).　Component (A): a monofunctional radical-polymerizable compound containing a compound represented by formula [1] Component (B): a radical initiator (In formula [1], X1 represents a structure selected from among formulae [1-a] to [1-g].　X2 represents a linear C2-14 alkylene group. The alkylene group may be subjected to specific substitution.　X3 represents -O-, -CO-, -COO-, -OCO-, -CONH-, -NHCO-, or-NH-.　X4 represents a linear or branched C12-40 alkyl group.) (TA represents a hydrogen atom or a benzene ring. * indicates a bond.)

Description

Technical Field

[0001] The present invention relates to a curable composition and a cured product thereof.

Background Art

[0002] In display elements and semiconductor elements, various adhesives have been conventionally used for the purpose of attaching various members within the elements. The properties required for the adhesive are the adhesion between the base material and the member, as well as its processability and reliability.

[0003] In addition, adherends to be adhered include organic base materials such as printed wiring boards and transparent polyimide films, and inorganic base materials such as glass, aluminum, ITO (Indium Tin Oxide), and SiN (Silicon Nitride). Therefore, the adhesive requires a design according to each target adherend.

[0004] So far, for adhesives of display elements and semiconductor elements, thermally or ultraviolet-curable resin components of an epoxy curing system using a compound having a highly reliable epoxy group or a radical curing system using a radical polymerizable compound have been used (for example, Patent Document 1 and Patent Document 2).

[0005] The epoxy curing system includes a resin component containing a compound having an epoxy group or an epoxy resin and a curing catalyst that generates a cationic catalyst by heat or light. On the other hand, the radical curing system generally includes a resin component containing a compound having a radical polymerizable acrylate group or the like and a radical initiator that generates radicals by irradiation with heat or ultraviolet rays.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

[0007] With the thinning of optical elements, it has been required to reduce the film thickness of the adhesive layer (also referred to as an adhesive layer) used therefor. In order to reduce the film thickness of the adhesive layer, it is necessary to reduce the film thickness of the curable composition applied to the substrate. However, many of the curable compositions using compounds having an epoxy group heretofore have high viscosities, and when they are applied with a thin film thickness, peeling and coating unevenness are likely to occur.

[0008] In addition, in the case of a radical-curable composition, since radicals are easily inhibited by oxygen, the curability of the adhesive layer is lowered. Further, compared with those using an epoxy group, since the curing shrinkage during curing is large, there are problems such as distortion and voids occurring at the interface between the substrate and the adhesive layer, or the adhesive strength (also referred to as adhesion) to the substrate being lowered.

[0009] From the above points, an object of the present invention is to provide a radical-curable composition having a low viscosity, a small curing shrinkage, and a high adhesion. [Means for Solving the Problems]

[0010] As a result of intensive studies to achieve the above object, the present inventor has completed the present invention having the following gist. That is, it is a curable composition containing the following component (A) and component (B). Component (A): A monofunctional radically polymerizable compound containing a compound represented by the following formula [1] (also referred to as a specific compound) Component (B): A radical initiator [Chemical Formula] (In formula [1], X 1 represents a structure selected from the following formulas [1-a] to [1-g]. X 2This represents a linear alkylene group having 2 to 14 carbon atoms. However, the alkylene group may be substituted with at least one of the following (i) and (ii). (i): X of the alkylene group above 1 or X 3 Substitution of any non-adjacent -CH2- to -O-, -CO-, -COO-, -OCO-, -CONH-, -NHCO-, -NH-, benzene ring, or cyclohexane ring (ii) Substitution of any -CH2- in the alkylene group with -CH(CH3)- X 3 -O-, -CO-, -COO-, -OCO-, -CONH-, -NHCO-, or -NH- represent -O-, -CO-, -COO-, -COO-, -CO-, -CONH-, -NHCO-, or -NH-. X 4 (This represents a linear or branched alkyl group having 12 to 40 carbon atoms.) [ka] (T A (* represents a hydrogen atom or a benzene ring. * represents a bond.) [Effects of the Invention]

[0011] The curable composition of the present invention has low viscosity, allowing it to be used with various coating methods and enabling uniform coating without uneven film thickness. Furthermore, when the curable composition of the present invention is used as an adhesive for display elements or semiconductor elements, the small curing shrinkage and high adhesion suppress the generation of strain and voids between the substrate and the adhesive layer, resulting in a highly reliable element. The mechanism by which the present invention yields a curable composition with the above-mentioned excellent properties is not entirely clear, but it is presumed to be approximately as follows. The curable composition uses a radical-curable polymerizable compound that reacts with radicals. Therefore, because it has a lower viscosity than compounds containing epoxy groups, the curable composition using it has a lower viscosity. Furthermore, X in the above formula [1] in a specific compound 4The structure is a long-chain alkyl group that lowers the Tg of the cured product. Therefore, the curable composition containing the specific compound cures while maintaining viscosity, resulting in high adhesion to the substrate and members. Furthermore, X 4 The structure has a large excluded volume between molecules, enabling reduction of curing shrinkage.

Brief Description of the Drawings

[0012] [Figure 1A] It is a schematic view of the test cell used for adhesion evaluation as seen from above. [Figure 1B] It is a schematic view of the test cell used for adhesion evaluation as seen from the side. [Figure 2A] It is a schematic view of the U-shaped upper jig used for adhesion evaluation. [Figure 2B] It is a schematic view of the U-shaped lower jig used for adhesion evaluation. [Figure 3] It is a schematic view of the test cell as seen from above, explaining the region where the test cell and the U-shaped jig contact during adhesion evaluation.

Modes for Carrying Out the Invention

[0013] Hereinafter, the present invention will be specifically described. The curable composition of the present invention contains the following component (A) and component (B). Component (A): A monofunctional radically polymerizable compound containing the compound represented by the above formula [1] Component (B): A radical initiator Another aspect of the present invention is the compound represented by the above formula [1].

[0014] <(Component A)> Component (A) is a monofunctional radically polymerizable compound containing the compound represented by the above formula [1] (also referred to as a specific compound) as an essential component. Here, a monofunctional radically polymerizable compound is a compound having one functional group that reacts with radicals in the molecule. In formula [1], X 1 , X 2 , X 3 and X4 As defined above, the following are preferred among them. X 1 From the viewpoint of enhancing the reactivity of the radical reaction, the structure represented by formula [1-a], formula [1-b], formula [1-c], or formula [1-d] is preferred. X 2 A structure represented by the following formula [X1a] is preferred. [ka] (In formula [X1a], M 1 and M 2 These independently represent -CH2-CH2-, -CH(CH3)-CH2-, or -CH2-CH(CH3)-. 1 represents -O-, -CO-, -COO-, or -OCO-. n represents an integer from 0 to 4. If n is an integer greater than or equal to 2, there are n Z 1 and M 2 Each of the above definitions is independent. *1 is X 1 This indicates the bonding position with X, where *2 is X 3 (This indicates the bonding position.)

[0015] X 3 -O-, -CO-, -COO-, or -OCO- are preferred. X 4 From the viewpoint of lowering the Tg of the cured product and increasing the intermolecular exclusion volume, branched alkyl groups having 12 to 40 carbon atoms are preferred.

[0016] Among these, the compound represented by the following formula [1a] is even more preferred. [ka] (In formula [1a], R 1 L represents a hydrogen atom or a methyl group. 1 and L 2 These independently represent -CH2-CH2-, -CH(CH3)-CH2-, or -CH2-CH(CH3)-. 1-O-, -CO-, -COO-, or -OCO-. n is an integer from 0 to 4. If n is an integer greater than or equal to 2, there are n Y 1 and L 2 Each of these has its own independent definition. Y 2 L indicates -COO- or -OCO-. 3 R represents a single bond or a linear or branched alkylene group having 1 to 4 carbon atoms. 2 and R 3 Each of these independently represents a linear or branched alkyl group having 4 to 18 carbon atoms. 4 L represents a hydrogen atom, or a linear or branched alkyl group having 1 to 18 carbon atoms. However, L 3 If L represents a group other than a single bond, 3 , and R 2 ~R 4 The total number of carbon atoms is 11-39, L 3 When R represents a single bond, 2 ~R 4 The total number of carbon atoms is between 11 and 39.

[0017] Specific examples of particular compounds include those represented by the following formulas [A1] to [A5], and it is preferable to use these. [ka]

[0018] Furthermore, in order to adjust the liquid properties of the curable composition and the film properties of the cured product, component (A) may also contain monofunctional radical polymerizable compounds other than the specified compound.

[0019] Examples of monofunctional radical polymerizable compounds other than the specified compounds include 2-ethylhexyl acrylate, 1-butyl ethyl acrylate, 2-butoxyethyl acrylate, 2-cyanoethyl acrylate, benzyl acrylate, cyclohexyl acrylate, 2-hydroxypropyl acrylate, 2-ethoxyethyl acrylate, N,N-diethyl-2-aminoethyl acrylate, N,N-dimethyl-2-aminoethyl acrylate, dicyclopentanyl acrylate, dicyclopentenyl acrylate, Glycidyl acrylate, tetrahydrofurfuryl acrylate, isobornyl acrylate, isodecyl acrylate, lauryl acrylate, 4-acryloylmorpholine, 2-phenoxyethyl acrylate, diethylene glycol acrylate phenyl ether, 2,2,2-trifluoroethyl acrylate, 2,2,3,3,3-pentafluoropropyl acrylate, 2,2,3,3-tetrafluoropropyl acrylate, 2,2,3,4,4,4-hexafluorobutyl acrylate, 2-ethyl Dihexyl methacrylate, 1-butylethyl methacrylate, 2-butoxyethyl methacrylate, 2-cyanoethyl methacrylate, benzyl methacrylate, cyclohexyl methacrylate, 2-hydroxypropyl methacrylate, 2-ethoxyethyl acrylate, N,N-diethyl-2-aminoethyl methacrylate, N,N-dimethyl-2-aminoethyl methacrylate, dicyclopentanyl methacrylate, dicyclopentenyl methacrylate, glycidyl methacrylate, tetrahydrofur Examples include methacrylate, isobornyl methacrylate, isodecyl methacrylate, lauryl methacrylate, 4-methacryloylmorpholine, 2-phenoxyethyl methacrylate, diethylene glycol methacrylate phenyl ether, 2,2,2-trifluoroethyl methacrylate, 2,2,3,3-tetrafluoropropyl methacrylate, 2,2,3,4,4,4-hexafluorobutyl methacrylate, nonylphenol EO modified acrylate, and nonylphenol EO modified methacrylate.

[0020] More specifically, examples include NK ester A-LEN-10, AM-90G, AM-130G, AMP-20GY, A-SA, S-1800A, CB-1, M-90G, M-230G, PHE-1G, S, SA (all manufactured by Shin Nakamura Chemical Industry Co., Ltd.), and Aronics M-111, M-120, M-140 (all manufactured by Toagosei Co., Ltd.).

[0021] Other monofunctional radical polymerizable compounds may include monofunctional aromatic urethane acrylates or aliphatic urethane acrylates, from the viewpoint of curability and curing shrinkage of the adhesive layer.

[0022] In addition, other monofunctional radical polymerizable compounds may include compounds having a thiol group in their molecule, in order to enhance the adhesion between the adhesive layer and the substrate. Specifically, examples include 1-decanethiol, 1-dodecanethiol, 1-hexadecanethiol, 1-octanethiol, and 1-octadecanethiol.

[0023] Furthermore, it is preferable to include a compound having a phosphate group in its molecule as a monofunctional radical polymerizable compound other than those mentioned above, for the purpose of improving the adhesion between the adhesive layer and the substrate. Specific examples of monofunctional radical polymerizable compounds having a phosphate group in their molecule include Phosmer M, PE, PP (all manufactured by Unichemical Co., Ltd.), Light Acrylate P-1A(N), and Light Ester P-1M (both manufactured by Kyoeisha Chemical Co., Ltd.).

[0024] (A) Component can use only a specific compound, or it can be used as a mixture of two or more specific compounds. It is also possible to use a mixture of one or more specific compounds and one or more monofunctional radical polymerizable compounds other than the specific compound. In component (A), the ratio of the specific compound to the monofunctional radical polymerizable compounds other than the specific compound is preferably such that the specific compound is present in a quantity of 10 parts by mass or more when the total amount of component (A) is 100 parts by mass.

[0025] <(B) component> Component (B) can include a thermal radical initiator that generates radicals with heat, and a photoradical initiator that generates radicals with ultraviolet light. These are appropriately selected depending on the curing process of the curable composition.

[0026] Examples of thermal radical initiators that generate radicals with heat include compounds having a ketone peroxide structure, peroxyketal structure, hydroperoxide structure, dialkyl peroxide structure, diacyl peroxide structure, peroxyester structure, peroxydicarbonate structure, or azo structure. However, if a thermal radical initiator that generates gas during radical generation is used, voids may be created. Therefore, compounds having a ketone peroxide structure, peroxyketal structure, hydroperoxide structure, dialkyl peroxide structure, diacyl peroxide structure, peroxyester structure, or peroxydicarbonate structure are preferred as thermal radical initiators.

[0027] Specifically, diisobutyryl peroxide, cumyl peroxyneodecanoate, di-n-propyl peroxydicarbonate, diisopropyl peroxydicarbonate, di-sec-butyl peroxydicarbonate, 1,1,3,3-tetramethylbutyl peroxyneodecanate, bis(4-tert-butylcyclohexyl) peroxydicarbonate, bis(2-ethylhexyl) peroxydicarbonate, tert-hexyl peroxyneodecanoate, tert-butyl peroxyneodecanoate, tert-butyl Peroxyneoheptanoate, tert-hexylperoxypivalate, tert-butylperoxypivalate, bis(3,5,5-trimethylhexanoyl)peroxide, dilaurylperoxide, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, disuccinate peroxide, 2,5-dimethyl-2,5-bis(2-ethylhexanoylperoxy)hexane, tert-hexylperoxy-2-ethylhexanoate, di(4-methylbenzoyl)peroxide, tert-butylperoxy Xy-2-ethylhexanoate, dibenzoyl peroxide, 1,1-bis(t-butylperoxy)-2-methylcyclohexane, 1,1-bis(tert-hexylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(tert-hexylperoxy)cyclohexane, 1,1-bis(tert-butylperoxy)cyclohexane, 2,2-bis(4,4-di-(tert-butylperoxy)cyclohexyl)propane, tert-hexylperoxyisopropyl monocarbonate, tert-butylperoxy Xymaleic acid, tert-butyl peroxy-3,5,5-trimethylhexanoate, tert-butyl peroxylaurate, tert-butyl peroxyisopropyl monocarbonate, tert-butyl peroxy-2-ethylhexyl monocarbonate, tert-hexyl peroxybenzoate, 2,5-dimethyl-2,5-bis(benzoylperoxy)hexane, tert-butyl peroxyacetate, 2,2-bis(tert-butylperoxy)butane, tert-butyl peroxybenzoate, n-butyl-4,Examples include 4-bis(tert-butylperoxy)valerate, 1,4-bis(tert-butylperoxyisopropyl)benzene, dicumyl peroxide, di-tert-hexyl peroxide, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, tert-butylcumyl peroxide, di-tert-butyl peroxide, p-menthane hydroperoxide, 2,5-dimethyl-2,5-bis(tert-butylperoxy)-3-hexine, diisopropylbenzene hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, cumene hydroperoxide, and tert-butyl hydroperoxide.

[0028] More specifically, these include Perloyl IB, Perloyl ND, Perloyl NPP, Perloyl IPP, Perloyl SBP, Perocta ND, Perloyl TCP, Perloyl OPP, Perhexyl ND, Perbutyl ND, Perbutyl NHP, Perhexyl PV, Perbutyl PV, Perloyl 355, Perloyl L, Perocta O, Perloyl SA, Perhexa 25O, Perhexyl O, Naiper PMB, Perbutyl O, Naiper BMT, Naiper BW, Perhexa MC, Perhexa TMH, and Perhexa HC. Examples include Perhexa C, Pertetra A, Perhexyl I, Perbutyl MA, Perbutyl 355, Perbutyl L, Perbutyl I, Perbutyl E, Perhexyl Z, Perhexa 25Z, Perbutyl A, Perhexa 22, Perbutyl Z, Perhexa V, Perbutyl P, Permil D, Perhexyl D, Perhexa 25B, Perbutyl C, Perbutyl D, Permenta H, Perhexin 25B, Permil P, Perocta H, Permil H, Perbutyl H, or Nofmer BC (all manufactured by NOF Corporation).

[0029] In particular, from the viewpoint of reactivity and reaction initiation temperature, it is preferable to use bis(4-tert-butylcyclohexyl)peroxydicarbonate (Perloyl TCP / manufactured by NOF Corporation), tert-butylperoxypivalate (Perbutyl PV / manufactured by NOF Corporation), 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate (Perocta O / manufactured by NOF Corporation), 1,1-bis(tert-hexylperoxy)cyclohexane (Perhexa HC / manufactured by NOF Corporation), 2,5-dimethyl-2,5-di(benzoylperoxy)hexane (Perhexa 25Z / manufactured by NOF Corporation), tert-butylperoxybenzoate (Perbutyl Z / manufactured by NOF Corporation), and 1,4-bis(tert-butylperoxyisopropyl)benzene (Perbutyl P / manufactured by NOF Corporation).

[0030] The amount of thermal radical initiator used is preferably 0.01 to 10 parts by mass per 100 parts by mass of all radical polymerizable compounds, including component (A), from the viewpoint of storage stability and curability of the curable composition. More preferably, it is 0.05 to 5 parts by mass. Furthermore, these thermal radical initiators can be used individually or in mixtures of two or more types, depending on the above-mentioned properties.

[0031] Examples of photoradical initiators that generate radicals under ultraviolet light include 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methyl-1-phenylpropane-1-one, 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methylpropane-1-one, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methylpropionyl)-benzyl]phenyl}-2-methylpropane-1-one, 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropane-1-one, 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morphonyl)phenyl]-1-butanone, and 2,4,6-trimethyl Examples include benzoyl diphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, 1-[4-(phenylthio)phenyl]octane-1,2-dione=2-(O-benzoyl oxime)], 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]-ethanone=1-(O-acetyl oxime), methylbenzoyl formate, a mixture of oxyphenyl-acetic acid 2-[2-oxo-2-phenyl-acetoxy-ethoxy]ethyl ester and oxyphenyl acetate-2-[2-hydroxy-ethoxy]ethyl ester, or 2-benzyl-2-(dimethylamino)-1-[4-(4-morpholinyl)phenyl]-1-butanone.

[0032] More specifically, examples include Omnirad1173, 184, 127, 2959, 369, 379, 389, 907, 4265, 1000, 651, TPO-H, TPO-L, 819, 819DW, 2022, 2100, 754, OXE-01, OXE-02, OXE-03, OXE-04, BPFlakes, 4MBZFlakes, OMBB, 1601, BMS, ITX, DETX, BBF, EMK, EsacureKIP150, KIP100F, or TZT (all manufactured by IGM Resins).

[0033] In particular, from the standpoint of reactivity and wavelength selectivity, 1-hydroxycyclohexylphenyl ketone (Omnirad184 / IGM Resins), 2-hydroxy-2-methyl-1-phenylpropan-1-one (Omnirad1173 / IGM Resins), 2-benzyl-2-(dimethylamino)-1-[4-(4-morpholinyl)phenyl]-1-butanone (Omnirad369 / IGM Resins), 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one (Omnirad907 / IGM Resins), bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (Omnirad819 / IGM Resins), and 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (OmniradTPO-H / IGM It is preferable to use 1-[4-(phenylthio)phenyl]octane-1,2-dione=2-(O-benzoyl oxime)](O-acetyl oxime) (OmniradOXE01 / IGM Resins), OmniradTPO-L / IGM Resins, and 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]-ethanone=2,1-(O-acetyl oxime) (OmniradOXE02 / IGM Resins).

[0034] The amount of photoradical initiator used is preferably 0.01 to 10 parts by mass per 100 parts by mass of all radical polymerizable compounds, including component (A), from the viewpoint of curability of the adhesive layer. More preferably, it is 0.05 to 5 parts by mass. Furthermore, these photoradical initiators can be used individually or in mixtures of two or more types, depending on the wavelength of the light source used in the curing process and the curability of the adhesive layer.

[0035] <(C) component> In the present invention, from the viewpoint of the curability and film strength of the adhesive layer, it is also preferable to use a difunctional or more radical polymerizable compound (hereinafter referred to as a polyfunctional radical polymerizable compound) having two or more radical-reactive functional groups in its molecule as component (C).

[0036] Specifically, the following polyfunctional radical polymerizable compounds are examples. For example, 4,4'-biphenyl diacrylate, diethylstilbestrol diacrylate, 1,4-bisacryloyloxybenzene, 4,4'-bisacryloyloxydiphenyl ether, 4,4'-bisacryloyloxydiphenylmethane, 3,9-[1,1-dimethyl-2-acryloyloxyethyl]-2,4,8,10-tetraspiro[5,5]undecane, α,α'-bis[4-acryloyloxyphenyl]-1,4-diisopropylbenzene, 1,4-bi Acryloyloxytetrafluorobenzene, 4,4'-bisacryloyloxyoctafluorobiphenyl, diethylene glycol diacrylate, 1,4-butanediol diacrylate, 1,3-butylene glycol diacrylate, glycerol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, tetraethylene glycol diacrylate, trimethylolpropane triacrylate, pentaerythritol tetraacrylate, pentaerythritol triacrylate, ditrimethylolpropane tetraacrylate, dipentaerythritol hexaacrylate, dipentaerythritol monohydroxypentaacrylate, 4,4'-diacryloyloxystilbene, 4,4'-diacryloyloxydimethylstilbene, 4,4'-diacryloyloxydiethylstilbene, 4,4'-diacryloyloxydipropylstilbene, 4,4'-diacryloyloxydibutylstilbene, 4,4'-Diacryloyloxydipentylstilbene, 4,4'-Diacryloyloxydihexylstilbene, 4,4'-Diacryloyloxydifluorostilbene, 2,2,3,3,4,4-Hexafluoropentanediol-1,5-Diacrylate, 1,1,2,2,3,3-Hexafluoropropyl-1,3-Diacrylate, Diethylene glycol dimethacrylate, 1,4-Butanediol dimethacrylate, 1,3-Butylene glycol dimethacrylate, 1,6-Hexanediol dimethacrylate, neopentyl glycol dimethacrylate, tetraethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, pentaerythritol tetramethacrylate, pentaerythritol trimethacrylate, ditrimethylolpropane tetramethacrylate, dipentaerythritol hexamethacrylate, dipentaerythritol monohydroxypentamethacrylate, 2,2,3,3,4,4-hexafluoropentanediol-1,5-dimethacrylate, tricyclodecane dimethanol diacrylate, tricyclodecane dimethanol dimethacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, polypropylene glycol #400 diacrylate, polypropylene glycol #700 diacrylate, Examples include monomers and oligomers such as dipropylene glycol dimethacrylate, tripropylene glycol dimethacrylate, polypropylene glycol #400 dimethacrylate, polypropylene glycol #700 dimethacrylate, polyethylene glycol #200 diacrylate, polyethylene glycol #400 diacrylate, polyethylene glycol #600 diacrylate, polyethylene glycol #200 dimethacrylate, polyethylene glycol #400 dimethacrylate, polyethylene glycol #600 dimethacrylate, ethoxylated bisphenol A diacrylate, propoxylated bisphenol A diacrylate, ethoxylated bisphenol A dimethacrylate, propoxylated bisphenol A dimethacrylate, or ethoxylated pentaerythritol tetraacrylate.

[0037] More specifically, NK Ester 701A, A-200, A-400, A-600, A-1000, A-B1206PE, ABE-300, A-BPE-1 0, A-BPE-20, A-BPE-30, A-BPE-4, A-BPEF, A-BPP-3, A-DCP, A-DOD-N, A-HD-N, A-NOD- N, APG-100, APG-200, APG-400, APG-700, A-PTMG-65, A-9300, A-9300-1CL, A-GLY-9E , A-GLY-20E, A-TMM-3, A-TMM-3L, A-TMM-3LM-N, A-TMPT, AD-TMP, ATM-35E, A-TMMT, A Examples include -9550, A-DPH, 1G, 2G, 3G, 4G, 9G, 14G, 23G, BPE-80N, BPE-100, BPE-200, BPE-500, BPE-900, BPE-1300N, DCP, DOD-N, HD-N, NOD-N, NPG, 1206PE, 701, 9PG, TMPT (all manufactured by Shin Nakamura Chemical Industry Co., Ltd.), KAYARADFM-400, HX-220, HX-620, R-712 (all manufactured by Nippon Kayaku Co., Ltd.), Bremmer PDE-100, PDE-200, PDE-400, PDP-400N, ADE-200, ADE-300, ADE-400A, or ADP-400 (all manufactured by NOF Corporation).

[0038] In particular, tricyclodecanedimethanol diacrylate, tricyclodecanedimethanol dimethacrylate, polyethylene glycol #200 diacrylate, polyethylene glycol #400 diacrylate, polyethylene glycol #600 diacrylate, polyethylene glycol #200 dimethacrylate, polyethylene glycol #400 dimethacrylate, polyethylene glycol #600 dimethacrylate, tripropylene glycol diacrylate, polypropylene glycol #400 diacrylate, polypropylene glycol #700 diacrylate, tripropylene glycol dimethacrylate, polypropylene glycol #400 dimethacrylate, polypropylene glycol #700 dimethacrylate, ethoxylated bisphenol A diacrylate, ethoxylated bisphenol A dimethacrylate, KAYARADFM-400, HX-220, and HX-620 (all manufactured by Nippon Kayaku Co., Ltd.) are preferred in terms of adhesive layer strength and curing shrinkage.

[0039] Component (C) preferably includes aromatic urethane polyfunctional acrylate or aliphatic urethane polyfunctional acrylate from the viewpoint of curability and curing shrinkage of the adhesive layer. Specifically, examples include EBECRYL210, 220, 230, 270, 4858, 8402, 8804, 8807, 9270, 4513, 4738, 4740, 8311, 9260, 8701, 4265, 4587, 4666, 8210, 1290, 5129, 8301R, 4501, 2221, 1271, 4859, 8409, 8465, 8809, 8810, 8811, 4101, 4201, 8209, 1291, 8602, 225, KRM8191, 8667, 8296, 8200, 8904, or 8452 (all manufactured by Daicel Ornex Co., Ltd.).

[0040] In particular, from the viewpoint of transparency of the adhesive layer, it is preferable to include the aliphatic urethane polyfunctional acrylates EBECRYL230, 4858, 8402, 8804, 8807, 4859, 8465, 8809, and 8811 (all manufactured by Daicel Ornex Co., Ltd.).

[0041] Furthermore, component (C) preferably contains a polyfunctional radical polymerizable compound having a thiol group in its molecule, in order to enhance the adhesion between the adhesive layer and the substrate. Specifically, this includes trimethylolpropane tris(3-mercaptopropionate), tris-[(3-mercaptopropionyloxy)-ethyl]-isocyanurate, pentaerythritol tetrakis(3-mercaptopropionate), tetraethylene glycol bis(3-mercaptopropionate), dipentaerythritol hexakis(3-mercaptopropionate), trimethylolpropane tris(3-mercaptobutyrate), trimethylol Examples include tris(3-mercaptobutyrate), pentaerythritol tetrakis(3-mercaptobutyrate), 1,3,5-tris(3-mercaptobutyryloxyethyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione, neopentanetetrathiol, pentaerythritol tetrakis(3-mercaptopropionate), and dipentaerythritol hexakis(3-mercaptopropionate). More specifically, examples include Karens MTPE1, BD1, NR1, and TPMB (all manufactured by Showa Denko Corporation). Among these, it is preferable to include Karens MTPE1, BD1, and NR1 (all manufactured by Showa Denko Corporation). The blending ratio of the polyfunctional radical polymerizable compound having a thiol group in its molecule is preferably 0.05 to 10 parts by mass, and more preferably 0.1 to 5 parts by mass, per 100 parts by mass of the total of components (A) and (C). Compounds containing thiol groups act as chain transfer agents in radical polymerization. Typically, residues of compounds with one thiol group in their molecule are located at the end of the polymerization chain, similar to initiators. However, when compounds containing two or more thiol groups are used, they not only act as chain transfer agents, but also undergo growth reactions from two or more thiol groups, resulting in residues of the compound being located in the middle of the polymerization chain. Furthermore, when compounds containing three or more thiol groups are used, growth reactions occur from three or more thiol groups, resulting in residues of the compound potentially acting as crosslinking points in the polymerization chain. Therefore, in this invention, compounds containing two or more thiol groups are included in the category of polyfunctional radical polymerizable compounds.

[0042] Furthermore, to enhance the adhesion between the adhesive layer and the substrate, a polyfunctional radical polymerizable compound having a phosphate group in its molecule may be used. Specifically, examples include KAYAMERPM-2 or PM-21 (both manufactured by Nippon Kayaku Co., Ltd.). The blending ratio of the polyfunctional radical polymerizable compound containing a phosphate group in its molecule is preferably 0.01 to 3 parts by mass, and more preferably 0.05 to 2 parts by mass, per 100 parts by mass of the total of components (A) and (C).

[0043] (C) Component can be used by mixing one or more of these polyfunctional radical polymerizable compounds.

[0044] <Curable composition> The curable composition contains components (A) and (B). In this case, component (C) may also be included from the viewpoint of curability and film strength of the adhesive layer.

[0045] When component (A) and component (C) are included, the blending ratio of component (A) is preferably 10 to 99 parts by mass per 100 parts by mass of the total of component (A) and component (C). More preferably, 20 to 95 parts by mass, and even more preferably, 40 to 90 parts by mass. Furthermore, it is preferable that component (C) is included in an amount of 1 part by mass or more per 100 parts by mass of the total of component (A) and component (C). More preferably, 5 parts by mass or more, and even more preferably, 10 parts by mass or more. Furthermore, when component (A) and component (C) are included, the blending ratio of component (C) is preferably 90 parts by mass or less, more preferably 80 parts by mass or less, and even more preferably 60 parts by mass or less per 100 parts by mass of the total of component (A) and component (C). Furthermore, when component (A) and component (C) are included, the blending ratio of the compound represented by the above formula [1] is preferably 10 to 99 parts by mass per 100 parts by mass of the total of component (A) and component (C). Of these, 20 to 95 parts by mass is more preferable, and even more preferable is 40 to 90 parts by mass.

[0046] It is preferable to adjust the mixing ratio of components (A), (B), and (C) so that the viscosity of the curable composition at 25°C is 1 to 10,000 mPa·s. Furthermore, for application to the various coating methods shown below, it is preferable that the viscosity at 25°C is 1 to 500 mPa·s. In particular, from the viewpoint of maintaining dimensional control and reducing unevenness that occurs when the curable composition is applied or cured, 1 to 300 mPa·s is more preferable, and even more preferable is 1 to 100 mPa·s. Methods for preparing the curable composition include mixing components (A), (B), and (C) together, or mixing component (B) with a mixture of components (A) and (C) that has been mixed beforehand.

[0047] The curable composition can also be used as a varnish by adding a solvent. This improves the applicability to the substrate and enhances processability. The solvent used is not particularly limited as long as it uniformly dissolves components (A), (B), and (C), and any known solvent can be used. Specifically, examples include methanol, ethanol, isopropyl alcohol, acetone, toluene, tetrahydrofuran, hexane, ethyl acetate, 1-butanol, 2-methoxyethanol, 2-ethoxyethanol, cyclohexanone, propylene glycol monomethyl ether acetate, N-methyl-2-pyrrolidone, and γ-butyrolactone. These can be used individually or in combination of two or more. However, if it is necessary to reduce gas generation from the solvent, it is preferable not to add a solvent.

[0048] The curable composition may contain inorganic fillers or organic fillers. In particular, inorganic fillers are preferred in terms of improving the heat resistance of the adhesive layer. Examples of known inorganic fillers include aluminum hydroxide, magnesium hydroxide, boron nitride, crystalline silica, and amorphous silica. These can be used individually or in mixtures of two or more.

[0049] The curable composition may also include spacers to control the gaps (also called voids) in the adhesive layer.

[0050] The curable composition can be used, for example, as an adhesive. The cured product of the present invention is obtained from the curable composition or adhesive of the present invention. The cured product is obtained, for example, by curing the curable composition described later.

[0051] <Method for preparing the adhesive layer> The curable composition can be used as an adhesive for bonding substrates together, attaching components to substrates, or bonding liquid crystal display elements or organic EL elements together. An example of a bonding method includes the steps of: applying the curable composition to the bonding surface of one adherend (substrate); attaching the other adherend (substrate or component) to the bonding surface of the first adherend; and further curing the curable composition. Furthermore, when using the curable composition of the present invention as an adhesive, from the viewpoint of environmental, safety, and health considerations, the adhesive may be a solvent-free adhesive that substantially contains no solvent. Here, "substantially contained" means that the curable composition contains 0 to 0.5 parts by mass, preferably 0 to 0.2 parts by mass, of solvent per 100 parts by mass of the total amount of curable composition. Moreover, the curable composition of the present invention can also be used as a cured film, such as an insulating film, after being applied and cured.

[0052] Methods for applying the curable composition to a substrate include spin coating, slit coating, roll coating, inkjet printing, screen printing, bar coating, flexographic printing, gravure printing, die coating, and dispensing. These methods are appropriately selected depending on the type of substrate and the desired thickness of the adhesive layer. The curable composition of the present invention has low viscosity, making it ideal for inkjet application.

[0053] The curing treatment for the curable composition is appropriately selected depending on the type of radical initiator used.

[0054] In the case of a curable composition using a thermal radical initiator, the following method is suggested. After applying the curable composition using the above method, bonding the substrates together or attaching the component to the substrate, a heat treatment is performed. Examples of heating equipment used at this time include hot plates, heat-circulating ovens, and IR (infrared) ovens. Since the presence of oxygen inhibits curing, it is preferable to use an oxygen-free environment such as a nitrogen atmosphere or under vacuum. Furthermore, it is preferable to press the substrates together or the substrates together with the component during the heat treatment.

[0055] In the case of a curable composition using a photoradical initiator, the following methods can be used. One method involves applying the curable composition using the method described above, then bonding the other substrate or attaching a component, and irradiating with ultraviolet light. In this case, as described above, it is preferable to use a nitrogen atmosphere or a vacuum. Furthermore, in order to improve the accuracy of bonding or attachment, as a preliminary curing step, after applying the curable composition, the layer of curable composition after application is irradiated with ultraviolet light, the other substrate is bonded, or a component is attached, and the main curing treatment is performed. It is preferable to perform the ultraviolet irradiation in the preliminary curing step under atmospheric conditions. As for the main curing treatment, ultraviolet irradiation or heat treatment can be used. The amount of ultraviolet irradiation and the temperature of the heat treatment are appropriately selected depending on the type of substrate and the type of radical initiator. It is preferable to perform the ultraviolet irradiation and heat treatment under a nitrogen atmosphere. The oxygen concentration may be controlled to less than 100 mg / L.

[0056] The curing shrinkage rate of the curable composition of the present invention is preferably low, and in this embodiment, it is preferably 9.0% or less, and more preferably 8.5% or less. The curing shrinkage rate can be determined by the method described in "Evaluation of Curing Shrinkage Rate" below.

[0057] Light sources for ultraviolet irradiation devices used for ultraviolet irradiation include metal halide lamps, high-pressure mercury lamps, and LED light sources. In this case, the wavelength of ultraviolet light is preferably 250 to 450 nm, and more preferably 310 to 400 nm. From the perspective of improving productivity, the ultraviolet irradiance should be 1-50 mW / cm². 2 It is preferable to keep it within this range. The amount of ultraviolet irradiation should be 50 mJ / cm² from the viewpoint of ensuring sufficient curing. 2 ~30000 mJ / cm 2 It is preferable to set it within that range.

[0058] Suitable substrates for adhesion include oxides and nitrides (e.g., quartz, glass, silica, titania, alumina, sapphire, aluminosilicate glass, borosilicate glass, silicon nitride, SiON, ITO, IZO, and IGZO), plastics (e.g., polymethyl methacrylate, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, ABS, polycarbonate, polystyrene, epoxy, unsaturated polyester, melamine, diallyl phthalate, polyimide, urethane, nylon, polyethylene, polypropylene, cycloolefin polymers, polyvinyl chloride, and fluororesins (polytetrafluoroethylene resin, polychlorotrifluoride). Examples of substrates and sheet films include polyethylene resins, polyvinylidene fluoride resins, polyvinyl fluoride resins, perfluoroalkoxy fluororesins, tetrafluoroethylene-hexafluoropropylene copolymer resins, ethylene-tetrafluoroethylene copolymer resins, ethylene-chlorotrifluoroethylene copolymer resins, etc.), polybutadiene, polyisoprene, SBR, nitrile rubber, EPM, EPDM, epichlorohydrin rubber, neoprene rubber, porsulfide, butyl rubber, cellulose, cellulose derivatives, and cellulose analogs, etc., and metals (e.g., iron, aluminum, stainless steel, titanium, gold, silver, copper, zinc, molybdenum, and alloys thereof).

[0059] Among these, for optical element applications, preferred oxides and nitrides include glass, silica, alumina, aluminosilicate glass, borosilicate glass, silicon nitride, silicon dioxide (SiON), and ITO. Preferred plastics include polymethyl methacrylate, polyethylene terephthalate, polycarbonate, and polyimide. Preferred metals include aluminum, silver, copper, molybdenum, and alloys thereof.

[0060] The optical element of the present invention is obtained using the curable composition of the present invention. Furthermore, the optical element of the present invention can be obtained using the adhesive of the present invention.

[0061] The curable composition can also be suitably used as a encapsulation material for electronic devices. Examples of electronic devices include organic EL elements, organic thin-film solar cells, and light-emitting diode elements. Known methods can be used to encapsulate electronic devices. Specifically, the electronic device can be encapsulated by applying the curable composition onto a substrate or component using a spin-coating method or an inkjet method, and then curing it by heat treatment or ultraviolet irradiation. Furthermore, the curable composition can also be used as an adhesive when attaching acrylic plates, transparent polyimide resin plastic plates, or touch panel sensors to liquid crystal display elements, organic EL displays, quantum dot displays, etc. In this case, it can also be used when bonding liquid crystal display elements, organic EL displays, quantum dot displays, etc., together. [Examples]

[0062] The present invention will be further described in detail below with reference to examples, but it is not limited to these examples.

[0063] [Synthesis of specific compounds] Compounds A1 through A5 are novel compounds not yet published in the literature, and their synthesis methods are described in detail below.

[0064] The products (A1 to A5) described in Examples 1 to 5 below are 1 Identified by 1H-NMR analysis (analytical conditions are as follows). Equipment:BRUKER ADVANCE III-500MHz Measurement solvent: DMSO-d6, CDCl3 Reference substance: Tetramethylsilane (TMS) (δ 0.0 ppm for 1 H)

[0065] The abbreviations used in this invention have the following meanings. EDC·HCl: 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride DMAP: 4-dimethylaminopyridine

[0066] <Example 1: Synthesis of specific compound (A1)> [ka]

[0067] To 13.0 g, 99.9 mmol of 2-hydroxyethyl methacrylate, 2,2,4,8,10,10-hexamethylundecane-5-carboxylic acid (30.0 g, 105 mmol), methylene chloride (78 g), EDC·HCl (23.0 g, 120 mmol), and DMAP (1.22 g, 9.99 mmol) were charged, and the mixture was stirred at 25°C for 20 hours. After the reaction was complete, stirring was stopped, water (80 g) was added, and the mixture was separated and washed. This was followed by separation and washing with saturated sodium bicarbonate aqueous solution (80 g) and then with water (80 g). The organic layer was concentrated to obtain a pale yellow oil. Purification was performed by column chromatography (eluent: heptane / ethyl acetate = 4 / 1 (volume ratio)) to remove the solvent and obtain the specific compound (A1) (yield: 37 g, 93.3 mmol, yield: 98%). 1 H-NMR (500MHz / DMSO-d6): δ(ppm)=6.03(s,1H),5.69(s,1H),4.35-4.20(m,4H),2.18-2.11(m,1H),1.87(s,3H),1.79-0.72(m,34H).

[0068] <Example 2: Synthesis of specific compound (A2)> [ka]

[0069] Polyethylene glycol monomethacrylate (product name: Bremmer PE-90, manufactured by NOF Corporation) (16.0 g, 91.8 mmol) was charged with 2,2,4,8,10,10-hexamethylundecane-5-carboxylic acid (26.4 g, 92.8 mmol), methylene chloride (96 g), EDC·HCl (26.4 g, 138 mmol), and DMAP (1.12 g, 9.17 mmol), and the mixture was stirred at 25°C for 10 days. After the reaction was complete, stirring was stopped, water (96 g) was added and liquid-liquid washing was performed, followed by liquid-liquid washing with saturated sodium bicarbonate aqueous solution (96 g) and then liquid-liquid washing with water (96 g). The organic layer was concentrated to obtain a pale yellow oil. Purification was performed by column chromatography (eluent: ethyl acetate), and by removing the solvent, the specific compound (A2) was obtained (yield: 35 g, 79.4 mmol, yield: 87%). 1 H-NMR (500MHz / DMSO-d6): δ(ppm)=6.03(s,1H),5.69(m,1H),4.39-4.05(m, 4H),3.70-3.45(m,4H),2.30-2.09(m,2H),1.88(s,3H),1.80-0.72(m,33H).

[0070] <Example 3: Synthesis of specific compound (A3)> [ka]

[0071] 2-(4,4-dimethyl-2-pentanyl)-5,7,7-trimethyl-1-octanol (40.0 g, 148 mmol) was charged with succinic anhydride (30.0 g, 300 mmol), ethyl acetate (240 g), pyridine (26.0 g, 325 mmol), and DMAP (1.80 g, 14.8 mmol), and the mixture was stirred at 90°C for 5 hours. After stopping the stirring and cooling to 25°C, the organic layer was concentrated by three separatory washes with water (120 g) to obtain an oil and a mixture of partially precipitated white crystals. Heptane (230 g) was added to this mixture, and the mixture was stirred at 25°C for 30 minutes and filtered to remove the white crystals. The filtrate was then washed twice with 1 N hydrochloric acid (230 g), and the organic layer was concentrated and dried to obtain compound (1) (yield: 54 g, 146 mmol, yield: 99%). 1 H-NMR (500MHz / DMSO-d6): δ(ppm)=12.2(s,1H),4.00-3.83(m,2H),2.53-2.53(m,4H),1.62-1.73(m,1H),1.49-0.72(m,34H).

[0072] Next, compound (1) (54.0 g, 146 mmol) was charged with 2-hydroxyethyl methacrylate (19.3 g, 148 mmol), methylene chloride (326 g), EDC·HCl (33.7 g, 176 mmol), and DMAP (1.80 g, 14.7 mmol), and the mixture was stirred at 25°C for 21 hours. After the reaction was complete, stirring was stopped, and water (326 g) and saturated saline solution (54 g) were added for liquid-liquid washing. Liquid-liquid washing was then performed twice with saturated sodium bicarbonate aqueous solution (272 g) and saturated saline solution (109 g), and the organic layer (including part of the aqueous layer) was concentrated. Heptane (320 g) was added and liquid-liquid extraction was performed, and the organic layer was concentrated again. Purification was performed by column chromatography (eluent: heptane / ethyl acetate = 4 / 1 (volume ratio)), and the specific compound (A3) was obtained by removing the solvent (yield: 57 g, 118 mmol, yield: 80%). 1 H-NMR (500MHz / DMSO-d6): δ(ppm)=6.03(s,1H),5.67(s,1H),4.27(s,4H),3.97-3. 85(m,2H),2.56-2.54(m,4H),1.87(s,3H),1.70-1.60(m,1H),1.49-0.72(m,34H).

[0073] <Example 4: Synthesis of specific compound (A4)> [ka]

[0074] 2-Hydroxyethyl methacrylate (16.9 g, 130 mmol) was charged with 2-hexyldecanoic acid (40.0 g, 156 mmol), methylene chloride (240 g), EDC·HCl (29.9 g, 156 mmol), and DMAP (1.59 g, 13.0 mmol), and the mixture was stirred at 25°C for 4 days. After the reaction was complete, stirring was stopped, water (80 g) was added, and the mixture was separated and washed to concentrate the organic layer. Heptane (240 g) was added, and the mixture was separated and washed with saturated sodium bicarbonate aqueous solution (240 g), dimethyl sulfoxide (240 g), and water (240 g), respectively, and the organic layer was concentrated. The resulting oil was purified by column chromatography (eluent: heptane / ethyl acetate = 4 / 1 (volume ratio)) to remove the solvent and obtain the specific compound (A4) (yield: 46 g, 124 mmol, yield: 95%). 1 H-NMR (500MHz / CDCl3): δ(ppm)=6.13(s,1H),5.58(s,1H),4.34-4.32(m,4H),2.39-2.32(m,1 H),1.94(s,3H),1.65-1.57(m,2H),1.45-1.43(m,2H),1.31-1.09(m,20H),0.88-0.87(m,6H).

[0075] <Example 5: Synthesis of a mixture of specific compounds (A5)> [ka]

[0076] To 15.2 g, 117 mmol of 2-hydroxyethyl methacrylate, 40.0 g, 141 mmol of a mixture of 2-octyldecanoic acid and 2-hexyldodecanoic acid (trade name: Isostearic Acid T, manufactured by Nissan Chemical Corporation), 240 g of methylene chloride, 27.0 g, 141 mmol of EDC·HCl, and 1.43 g, 11.7 mmol of DMAP were charged, and the mixture was stirred at 25°C for 24 hours. After the reaction was complete, stirring was stopped, water (240 g) was added, and the organic layer was concentrated by liquid-liquid washing. Heptane (240 g) was added, and the organic layer was concentrated by liquid-liquid washing in the following order: saturated sodium bicarbonate aqueous solution (240 g), dimethyl sulfoxide (240 g), and water (240 g). The obtained oil was purified by column chromatography (eluent: heptane / ethyl acetate = 4 / 1) to remove the solvent, thereby obtaining a mixture of specific compounds (A5) (yield: 42g, 106 mmol, yield: 91%). 1 H-NMR (500MHz / CDCl3): δ(ppm)=6.12(s,1H),5.58(s,1H),4.35-4.34(m,4H),2.39-2.32(m,1 H),1.95(s,3H),1.67-1.57(m,2H),1.45-1.43(m,2H),1.31-1.11(m,24H),0.89-0.86(m,6H).

[0077] [Compounds used in the preparation of curable compositions] <Specific compound> A1 to A5: Compounds and mixtures obtained in the above examples, respectively. <Monofunctional radical polymerizable compounds other than specified compounds> A6: Arronix M-111 (Nonylphenol EO-modified acrylate) (Manufactured by Toagosei Co., Ltd.) <Radical initiator> B1: Perhexa 25Z (manufactured by NOF Corporation) / Thermal radical initiator B2: OmniradTPO-H (manufactured by IGM Resins) / Photoradical initiator B3: OmniradOXE01 (manufactured by IGM Resins) / Photoradical initiator <Difunctional or more radical polymerizable compounds> C1: Bremmer PDE-200 (Polyethylene glycol #200 dimethacrylate) (Manufactured by NOF Corporation) C2: NK ester DCP (tricyclodecane dimethanol dimethacrylate) (manufactured by Shin-Nakamura Chemical Industry Co., Ltd.) C3: EBECRYL230 (manufactured by Daicel Ornex Co., Ltd.) / Urethane acrylate C4: EBECRYL9270 (manufactured by Daicel Ornex Co., Ltd.) / Urethane acrylate C5: Karenz MTBD1 (manufactured by Showa Denko Corporation) / Polymerizable compound containing a thiol group C6: Karenz MTPE1 (manufactured by Showa Denko Corporation) / Polymerizable compound containing a thiol group C7: KAYAMER PM-21 (manufactured by Nippon Kayaku Co., Ltd.) / Polymerizable compound containing a phosphate group

[0078] [Preparation of curable compositions] <Comparative Examples 1-2 and Examples 6-24> By mixing each component in the proportions (mass ratios) shown in Table 1 below, curable compositions (1) to (21) of Comparative Examples 1 to 2 and Examples 6 to 24 were obtained. In Table 1, the numerical values ​​represent the proportion (parts by mass) of each compound per 100 parts by mass of the curable composition.

[0079] [Table 1] In Table 1, "Other" refers to monofunctional radical polymerizable compounds other than the specified compounds.

[0080] Using the curable composition obtained above, the viscosity of the curable composition, the adhesion evaluation, and the curing shrinkage rate were evaluated using the following methods. For the evaluation of adhesion and curing shrinkage rate, the curable composition was pressure filtered through a membrane filter with a pore size of 1 μm.

[0081] [Measurement of viscosity of curable compositions] The viscosity of the curable composition was measured using an E-type viscometer TVE-25L (manufactured by Toki Sangyo Co., Ltd.) with a sample volume of 1.1 mL, a cone rotor TE-1 (1°34', R24), a rotation speed of 10 rpm during measurement, and a temperature of 25°C.

[0082] [Evaluation of adhesion] <Method for preparing test cells (curable composition using a thermal radical initiator)> Test cells were prepared using curable compositions (1), (3) to (9) containing a thermal radical initiator, respectively, by the following methods. Two glass substrates (length: 15 mm, width: 55 mm, thickness: 1.1 mm) were prepared after being washed with pure water, acetone, and IPA (isopropyl alcohol). 0.5% by mass of 4 μm bead spacers was added to the curable composition obtained above, and then spin-coated onto one of the glass substrates (lower glass substrate 1) to obtain a glass substrate with an uncured layer of curable composition (hereinafter also referred to as the glass substrate with the uncured curable composition layer). Then, as shown in Figure 1A, the other glass substrate (upper glass substrate 2) was brought into close contact with the glass substrate with the uncured curable composition layer so that their center points intersected in a direction perpendicular to each other, and the two substrates were pressed together using clips to obtain a bonded cell. After removing any unwanted curable composition adhering to the bonded cell, it was placed in a heat-circulating oven and heated at 140°C for 1 hour. After the treatment, the substrates were cooled and the clips were removed to obtain a test cell for adhesion evaluation (containing a cured product obtained from a curable composition using a thermal radical initiator). By adding bead spacers to the curable composition, an adhesive layer region 3 formed between the lower glass substrate 1 and the upper glass substrate 2 of the resulting test cell is created by the cured product obtained from the curable composition, as shown in Figure 1B.

[0083] <Method for preparing test cells (curable composition using photoradical initiator)> In Comparative Example 2 and Examples 13-22 (curable compositions (2), (10)-(19)), the coating surface of a glass substrate with an uncured curable composition layer, prepared by the same method as described above, was irradiated with ultraviolet light using an ultraviolet light-emitting diode under atmospheric conditions. Specifically, the wavelength of the light source of the ultraviolet light-emitting diode was 365 nm, and the irradiance of the ultraviolet light was 6.6 mW / cm². 2 The irradiation time was 30 seconds (total 198 mJ / cm²). 2 This corresponds to the irradiation dose.) Then, the other glass substrate (upper glass substrate 2) was brought into close contact with the glass substrate with the curable composition layer irradiated with the above ultraviolet light, with their center points intersecting in a direction perpendicular to each other, and the two substrates were pressed together using clips to obtain a press-fit cell. After removing any unwanted curable composition adhering to the press-fit cell, it was placed in a heat-circulating oven and heated at 140°C for 1 hour. After the treatment, the substrate was cooled and the clips were removed to obtain a test cell for adhesion evaluation (containing a cured product obtained from a curable composition using a photoradical initiator). In Examples 23 and 24 (curable compositions (20) and (21)), a glass substrate with an uncured curable composition layer was prepared using the same method as described above. The other glass substrate (upper glass substrate 2) was then placed in close contact with the glass substrate with the uncured curable composition layer so that their center points intersected in a direction perpendicular to each other. The two substrates were then pressed together using clips to obtain a crimped cell. The crimped cell was then fitted with a UV light-emitting diode light source with a wavelength of 365 nm and an UV irradiance of 6.6 mW / cm². 2 The ultraviolet light was irradiated for 220 seconds (total 1452 mJ / cm²). 2 This corresponds to the irradiation dose. A test cell for evaluating adhesion (including a cured product obtained from a curable composition using a photoradical initiator) was obtained.

[0084] <Method for evaluating adhesion> Adhesion was evaluated using a universal testing machine EZ-SX100N (Shimadzu Corporation) and U-shaped fixtures (upper fixture 4 and lower fixture 5) shown in Figures 2A and 2B. Specifically, the lower end 7 (the area in contact with the lower fixture 5) of the upper glass substrate 2 of the test cell, as shown in Figure 3, was set to contact the contact area 6 (the area in contact with the test cell) of the lower fixture 5 of the testing machine. Then, the upper fixture 4 of the testing machine was moved downward at a speed of 5 mm per second, and the upper fixture 4 was brought into contact with the upper end 8 (the area in contact with the upper fixture 4) of the lower glass substrate 1 of the test cell and pressed down, thereby vertically peeling the test cell, which consists of two substrates, from the surface of the adhesive layer (the cured product obtained from the curable composition). The adhesion was calculated by dividing the maximum force applied at this time by the area of ​​the adhesive layer region 3. A higher value indicated better adhesion.

[0085] "Evaluation of hardening shrinkage rate" The curing shrinkage rate was calculated using the density method, which utilizes the density of the curable composition and its cured product. Cured products of curable compositions using a thermal radical initiator were prepared by heat treatment at 140°C for 1 hour in a heat-circulating oven under a nitrogen atmosphere. Cured products of curable compositions using a photoradical initiator were prepared under a nitrogen atmosphere using an ultraviolet light-emitting diode with a wavelength of 365 nm and an ultraviolet irradiance of 6.6 mW / cm². 2 UV treatment with an irradiation time of 220 seconds (total 1452 mJ / cm²) 2 This corresponds to the irradiation dose. ) was produced by performing this procedure. A dry-type densimeter, AccuPic II (Shimadzu Corporation), was used to measure the density. The curing shrinkage rate was calculated using the following formula. Curing shrinkage rate (%) = ((d1 / d0)-1) × 100 In the above formula, d0 is the density of the curable composition before curing, and d1 is the density of the curable composition after curing. Furthermore, a lower curing shrinkage rate indicates less curing shrinkage, i.e., superior curing shrinkage resistance.

[0086] Table 2 shows the evaluation results of curable compositions using thermal radical initiators, and Table 3 shows the evaluation results of curable compositions using photoradical initiators.

[0087] [Table 2]

[0088] [Table 3]

[0089] As shown in Tables 2 to 3, the curable compositions containing the specific compounds obtained in Examples 6 to 24 exhibited lower viscosity, higher adhesion when curing the film, and smaller curing shrinkage compared to the comparative examples that did not use the specific compounds. Specifically, this was observed in comparisons between Comparative Example 1 and Example 7, and between Comparative Example 2 and Example 14, under identical conditions. Furthermore, when a compound containing a thiol group was used as the radical polymerizable compound, the adhesion was improved compared to when it was not used. Specifically, this was a comparison between Example 14 and Example 15 under identical conditions. In addition, when a compound containing a phosphate group was used as the radical polymerizable compound, the adhesion was improved compared to when it was not used. Specifically, this was a comparison between Example 17 and Example 18 under identical conditions. Furthermore, when aliphatic urethane acrylate was used as the radical polymerizable compound, curing shrinkage was reduced compared to when it was not used. Specifically, this was a comparison between Example 7 and Example 8 under identical conditions. Moreover, when polymerizable compounds having thiol groups and polymerizable compounds having phosphate groups were used in combination, using aliphatic urethane acrylate as the polymerizable compound reduced curing shrinkage and also improved adhesion. Specifically, this was a comparison between Example 18 and Example 19 under identical conditions. [Industrial applicability]

[0090] By using a curable composition containing a compound having a specific structure, a radical-curable type curable composition with low viscosity, small curing shrinkage, and high adhesion can be obtained. Therefore, display elements and semiconductor elements obtained using the curable composition of the present invention as an adhesive will have excellent reliability. [Explanation of symbols]

[0091] 1 Lower glass substrate 2 Upper glass substrate 3 Adhesive layer area 4 Upper jig 5 Lower jig 6 Contact area 7 Lower end 8 Upper end

Claims

1. A curable composition containing the following components (A) and (B). (A) Component: A monofunctional radical polymerizable compound containing the compound represented by the following formula [1a]. (B) Component: Radical initiator 【Chemistry 1】 (In formula [1a], R １ represents a hydrogen atom or a methyl group. L １ and L ２ each independently represent -CH ２ -CH ２ -, -CH(CH ３ )-CH ２ - or -CH ２ -CH(CH ３ ). Y １ represents -O-, -CO-, -COO- or -OCO-. n represents an integer from 0 to 4. When n is an integer of 2 or more, n Y １ and L ２ each independently have the above definitions. Y ２ represents -COO- or -OCO-. L ３ represents a single bond or a linear or branched alkylene group having 1 to 4 carbon atoms. R ２ and R ３ each independently represent a linear or branched alkyl group having 4 to 18 carbon atoms. R ４ represents a hydrogen atom or a linear or branched alkyl group having 1 to 18 carbon atoms. However, when L ３ represents a group other than a single bond, the total number of carbon atoms of L ３ , and R ２ to R ４ is 11 to 39, and when L ３ represents a single bond, the total number of carbon atoms of R ２ to R ４ is 11 to 39.)

2. The curable composition according to claim 1, comprising a bifunctional or more radical polymerizable compound as component (C).

3. The curable composition according to claim 2, wherein the radical polymerizable compound of component (C) comprises a compound having a phosphate group in its molecule.

4. The curable composition according to any one of claims 1 to 3, wherein the component (A) further comprises a monofunctional radical polymerizable compound having a phosphate group in the molecule.

5. The curable composition according to any one of claims 2 to 4, wherein the blending ratio of component (A) is 10 to 99 parts by mass with respect to 100 parts by mass of the total of component (A) and component (C).

6. The curable composition according to any one of claims 1 to 5, wherein the radical initiator is a thermal radical initiator that generates radicals with heat.

7. The curable composition according to any one of claims 1 to 5, wherein the radical initiator is a photoradical initiator that generates radicals when exposed to ultraviolet light.

8. An optical element obtained using the curable composition described in any one of claims 1 to 7.

9. An adhesive comprising the curable composition according to any one of claims 1 to 8.

10. The adhesive according to claim 9, wherein the adhesive is a solvent-free adhesive.

11. An optical element obtained using the adhesive described in claim 9 or 10.

12. A cured product obtained from the curable composition according to any one of claims 1 to 7.

13. A cured product obtained by irradiating the curable composition described in claim 7 with ultraviolet light and then heat-treating it.

14. A compound represented by the following formula [1a]. 【Chemistry 2】 (In formula [1a], R １ L represents a hydrogen atom or a methyl group. １ and L ２ Each is independent of the other, -CH ２ -CH ２ -, -CH(CH ３ ) - CH ２ - or -CH ２ -CH(CH ３ ) - indicates Y １ represents -O-, -CO-, -COO-, or -OCO-. n represents an integer from 0 to 4. If n is an integer of 2 or more, n Y １ and L ２ Each of these has its own independent definition. Y ２ indicates -COO- or -OCO-. ３ R represents a single bond or a linear or branched alkylene group having 1 to 4 carbon atoms. ２ and R ３ Each of these independently represents a linear or branched alkyl group having 4 to 18 carbon atoms. ４ L represents a hydrogen atom, or a linear or branched alkyl group having 1 to 18 carbon atoms. However, L ３ When L represents a group other than a single bond, ３ , and R ２ ~R ４ The total number of carbon atoms is 11 to 39, L ３ When R represents a single bond, ２ ~R ４ The total number of carbon atoms is between 11 and 39.

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