JP2009298888A - Optical post-curable composition - Google Patents

Abstract

【選択図】なしAn optical post-curing composition that can maintain excellent adhesiveness regardless of changes in temperature of use environment, has excellent transparency, and has a long pot life.
An epoxy modified silicone and / or an oxetane modified silicone, a cationic polymerizable monomer, a photo cationic polymerization initiator, and a crown ether type curing retardant having a structure represented by the following formula (1) are contained. Photo-curing composition.

[Selection figure] None

Description

The present invention relates to an optical post-curing composition that can maintain excellent adhesiveness regardless of changes in ambient temperature, has excellent transparency, and has a long pod life.

As a method for improving the impact resistance of a liquid crystal display device, for example, a liquid crystal panel having a structure in which liquid crystal is sealed between a pair of transparent substrates and the periphery is sealed with a sealing agent, and the liquid crystal panel is protected from external impact. A method of providing an air gap (air layer) between a protective substrate for protection has been conventionally performed.
However, since the liquid crystal display device provided with such an air layer has a structure in which materials having different refractive indexes are stacked, a part of the external light such as sunlight or the light from the backlight is reflected. As a result, light scattering occurs and the brightness and contrast of the display image are reduced. For example, in Patent Document 1, a transparent elastic resin is interposed between the liquid crystal panel and the transparent member in place of the air layer, and the liquid crystal panel and the transparent member are joined with the transparent elastic resin. It is disclosed.

Here, portable information communication devices such as mobile phones may be used in a very wide temperature range, for example, a temperature range of −30 to 60 ° C., and good display quality is obtained in such a temperature range. Need to keep. However, when the information communication device formed by joining the liquid crystal panel and the transparent member with the transparent elastic resin described in Patent Document 1 is used in such a wide temperature range, the liquid crystal panel and the transparent member There was a problem that peeling occurred at the interface with the cured product of the transparent elastic resin, and the display quality of the liquid crystal display device deteriorated.
Japanese Patent Laid-Open No. 11-174417

As a result of intensive studies, the present inventors have used a curable composition containing an epoxy-modified silicone or oxetane-modified silicone, a cationic polymerizable monomer, and a cationic polymerization initiator as an adhesive for electronic parts and the like. In such a case, it was found that excellent adhesiveness can be maintained regardless of changes in use environment temperature (Japanese Patent Application No. 2007-157629).
However, such a curable composition has a problem in that it takes a short time from irradiation to curing, that is, a pod life. When bonding electronic parts using a curable composition with a short pod life, it is necessary to irradiate light after combining the adherend of the electronic part and the curable composition. Parts may deteriorate. As a method for extending the pod life of the composition, a method of blending a curing retarder is common. However, when a general curing retardant is blended with the curable composition, there is a problem that it becomes cloudy and the transparency of the entire composition is lowered, and cannot be used for optical applications.
The present invention has been made in view of the above situation, and an object thereof is to provide an optical post-curing composition that can maintain excellent adhesiveness regardless of changes in use environment temperature, has excellent transparency, and has a long pod life. And

The present invention relates to an epoxy-modified silicone and / or oxetane-modified silicone, a cationically polymerizable monomer, a photocationic polymerization initiator, and a photo retarder containing a curing retarder having a structure represented by the following general formula (1). It is a curable composition.

In formula (1), at least one of R ^{21 to} R ³² represents an alkyl group having 1 to 20 carbon atoms, and the remainder represents hydrogen. The alkyl group is a linear or branched alkoxy group having 1 to 20 carbon atoms, halogen atom, —OH group, —COOH group, and —COO-alkyl ester group (provided that the alkyl moiety is linear Or may be substituted with one or more functional groups selected from the group consisting of branched-chain C1-20 residues, and adjacent R ⁿ and R ^{n + 1} (where n is , Each representing an odd number of 1 to 11) may form a cyclic alkyl skeleton.
The present invention is described in detail below.

As a result of intensive studies, the present inventors have determined a specific structure as a curing retarder in a curable composition containing an epoxy-modified silicone and / or an oxetane-modified silicone, a cationic polymerizable monomer, and a cationic polymerization initiator. When the compound which has it was mix | blended, it discovered that a pod life could be extended without impairing transparency, and came to complete this invention.

The post-photocurable composition of the present invention contains an epoxy-modified silicone and / or an oxetane-modified silicone, a cationic polymerizable monomer, a cationic polymerization initiator, and a curing retarder.
Although it does not specifically limit as said epoxy modified silicone and oxetane modified silicone, What is represented by the following general formula (3-1) and general formula (4) is suitable. The post-photocurable composition of the present invention containing such an epoxy-modified silicone or oxetane-modified silicone can exhibit stable adhesive force even when the usage environment changes, and peels off at the adherend interface. Will not occur.

In general formula (3-1), l, m, and n are ^{1 to} 500, R ¹ represents H and / or CH ₃ , and R ² is linear or branched having 1 to 6 carbon atoms. Represents a chain alkylene group, A represents a benzene ring or a cyclohexane ring, X represents CR ₂ , O, S (O ₂ ) or S, and Y represents an epoxy group, an oxetanyl group or an alicyclic epoxy group. Y ′ represents a structure in which an epoxy group, an oxetanyl group or an alicyclic epoxy group is opened, and R represents H and / or CH ₃ .

In the above general formula (3-1), the preferable lower limit of the number of repeating units “l”, “m” and “n” of the silicone skeleton portion is 1, the preferable upper limit is 500, and the more preferable upper limit of “l” is 200, “ A more preferable upper limit of m ”and“ n ”is 50.
In the general formula (3-1), the number of repeating units “n” of the silicone skeleton portion, the number of repeating units “m” composed of the bisphenol type epoxy skeleton, and the silicone skeleton portion and the bisphenol type epoxy skeleton When the number of repeating units “l” is within the above range, the photo-post-curing property of the present invention containing the epoxy-modified silicone represented by the general formula (3-1) and the oxetane-modified silicone as a photocationically polymerizable compound. The composition can exhibit a stable adhesive force even when the usage environment changes, and does not cause peeling at the interface of the adherend.

In the general formula (3-1), R ¹ represents H and / or CH ₃ , R ² represents a linear or branched alkylene group having 1 to 6 carbon atoms, and X represents CR ₂ , O, S (O ₂ ) or S, Y represents an epoxy group, oxetanyl group or alicyclic epoxy group, Y ′ represents a ring-opened structure of an epoxy group, oxetanyl group or alicyclic epoxy group. And R represents H and / or CH ₃ .

Specific examples of the structure of X, Y, and Y ′ include those represented by the following general formulas (3-2) to (3-4).

In the general formulas (3-2) to (3-4), R ³ , R ⁴ , and R ^{5 each} represent hydrogen or a linear or branched alkyl group having 1 to 6 carbon atoms.

The epoxy-modified silicone and oxetane-modified silicone represented by the general formula (3-1) are, for example, bisphenol when “A” is a benzene ring and X is CR ₂ in the general formula (3-1). It can be obtained by a condensation reaction of a mold type epoxy resin (oxetane resin) and a silicone resin by a known method.

Commercially available products of the bisphenol type epoxy resin include, for example, bisphenol A type epoxy resins such as Epicoat 828 and Epicoat 1004 (all manufactured by Japan Epoxy Resin), Epicoat 806 and Epicoat 4004 (all manufactured by Japan Epoxy Resin). Bisphenol F type epoxy resins such as R-710, and bisphenol E type epoxy resins such as R-710.

Moreover, as a commercial item of the epoxy-modified silicone represented by the general formula (3-1), for example, trade names “296”, “348”, “Nanoresin” epoxy silicone copolymer “ALBIFEX” series are available. XP544 "," 712 ", etc. are mentioned.

In formula (4), R ² represents H, CH ₃ or C ₂ H ₅ , p represents an integer of 1 to 100, and o represents an integer of 0 to 100.
At least one of R ³ , R ⁴ , R ⁵ and R ⁶ is represented by the following general formula (5-1), (5-2) or (5-3), and the remainder is H, CH ₃ or C ₂ H ₅ is represented, or at least one of the following general formula (6-1), (6-2) or (6-3), and the remainder is H, CH ₃ or C ₂ H ₅ , or any Or at least 1 represents the following general formula (7-1), (7-2) or (7-3), and the remainder represents H, CH ₃ or C ₂ H ₅ .

In the compound represented by the general formula (4), the lower limit of the number of repeating units “p” of the silicone skeleton is 1 and the upper limit is 100. By setting the number of repeating units of the silicone skeleton part in the above range, the curable composition for optical components of the present invention containing the epoxy-modified silicone represented by the general formula (4) and the oxetane-modified silicone as a photocationically polymerizable compound. The composition can exhibit a stable adhesive force even when the usage environment changes, and does not cause peeling at the interface of the adherend.

Specific examples of the compound having the structure represented by the general formula (4) include, for example, modified silicone oil manufactured by Shin-Etsu Silicone Co., Ltd., and those of the epoxy type include “X-22-163”. , “KF-105”, “X-22-163A”, “X-22-163B”, “X-22-163C” and the like, and as the alicyclic type, “X-22-169AS” And “X-22-169B”. In addition, as oxetane type, “OX-SQ”, “OX-SQ-H”, “OX-SQ-SI-20”, “Si-OX”, “OX-SC” (above, Toagosei Co., Ltd.) Manufactured) and the like.

The photocationically polymerizable compound is not particularly limited as long as it is a polymerizable monomer having at least one cation polymerizable functional group in the molecule. For example, at least one epoxy group or oxetanyl group in the molecule. , Compounds having a photocationically polymerizable functional group such as a hydroxyl group, a vinyl ether group, an episulfide group, and an ethyleneimine group. Of these, epoxy compounds are preferred.

The epoxy compound is not particularly limited, and examples thereof include bisphenol type epoxy compounds such as bisphenol A type epoxy compounds and bisphenol F type epoxy compounds, novolak type epoxy compounds such as phenol novolac type epoxy compounds and cresol novolak type epoxy compounds, and naphthalene. Type epoxy compound, aliphatic epoxy compound, alicyclic epoxy compound, heterocyclic epoxy compound, polyfunctional epoxy compound, biphenyl type epoxy compound, glycidyl ether type epoxy compound, glycidyl ester type epoxy compound, glycidyl amine type epoxy compound , Alcohol type epoxy compounds such as hydrogenated bisphenol A type epoxy compounds, halogenated epoxy compounds such as brominated epoxy compounds, rubber-modified epoxy compounds, urethane Forming epoxy compounds, epoxidized polybutadiene, epoxidized styrene - butadiene - styrene block copolymer, epoxy group-containing polyester compounds, epoxy group-containing polyurethane compound, an epoxy group-containing acrylic compounds. Among them, bisphenol A type epoxy compounds, naphthalene type epoxy compounds, alicyclic epoxy compounds, and the like are preferably used because they have higher photocationic polymerizability and more efficiently proceed with photocuring even with a small amount of light. These epoxy compounds may be used independently and 2 or more types may be used together.

The alicyclic epoxy compound is not particularly limited. For example, 1,2,8,9-diepoxy limonene, 4-vinylcyclohexene monooxide, vinylcyclohexene dioxide, methylated vinylcyclohexene dioxide, (3,4 -Epoxycyclohexyl) methyl-3,4-epoxycyclohexylcarboxylate, bis- (3,4-epoxycyclohexyl) adipate, bis- (3,4-epoxycyclohexylmethylene) adipate, bis- (2,3-epoxycyclopentyl) Ether, (2,3-epoxy-6-methylcyclohexylmethyl) adipate, dicyclopentadiene dioxide, etc., at least one 4- to 7-membered cyclic aliphatic group in the molecule and at least one epoxy in the molecule Compounds having a group It is. These alicyclic epoxy compounds may be used independently and 2 or more types may be used together.

There are no particular limitations on the commercially available products of the above epoxy compounds, for example, “Epicoat” series such as “Epicoat 807”, “Epicoat 828”, and “Epicoat 1001” manufactured by Japan Epoxy Resin, Dainippon Ink & Chemicals, Inc. “Epicron” series such as “Epiclon HP-4032” manufactured by the company, “Celoxide” series such as “Celoxide 2021” manufactured by Daicel Chemical Industries, Ltd., and the like.

The cationic polymerizable monomer preferably contains an aliphatic epoxy compound and / or an aliphatic oxetane compound. These aliphatic epoxy compounds and aliphatic oxetane compounds can also serve as diluents, and can adjust the viscosity of the photo-curable composition of the present invention.

The aliphatic epoxy compound is not particularly limited. For example, 2-ethylhexyl glycidyl ether (product name Denacol EX-141, manufactured by Nagase ChemteX Corporation), polytetramethylene glycol (di) glycidyl ether, polyneopentylene glycol ( Di) Glycidyl ether (product name YL-7217, manufactured by Japan Epoxy Resin Co., Ltd.) and the like. Of these, 2-ethylhexyl glycidyl ether is preferred because of its high flexibility and high reactivity.

The aliphatic oxetane compound is not particularly limited, and examples thereof include 3-ethyl-3- (2-ethylhexyloxymethyl) oxetane (product name: Aron Oxetane OXT-212, manufactured by Toagosei Co., Ltd.), 3-ethyl-3- Hydroxymethyloxetane (product name Aron Oxetane OXT-101, manufactured by Toagosei Co., Ltd.) and the like can be mentioned. Among them, 3-ethyl-3- (2-ethylhexyloxymethyl) oxetane is preferable because of its high flexibility and high reactivity.

The post-photocurable composition of the present invention contains a cationic polymerization initiator.
The cationic polymerization initiator is not particularly limited as long as it generates a protonic acid or a Lewis acid by light irradiation, whether it is an ionic photoacid generating type or a nonionic photoacid generating type. Good.

As the cationic polymerization initiator, an onium salt represented by the following general formula (8) is suitable. When an onium salt represented by the following general formula (8) is used as a cationic polymerization initiator, and a benzophenone derivative represented by the following general formula (10) is used as a sensitizer, the obtained light The curable composition is very little colored by light or heat.

In formula (8), R ¹¹ and R ¹² are hydrogen, a linear alkyl group having 1 to 20 carbon atoms, a branched alkyl group having 1 to 20 carbon atoms, or an alkoxyl group having 1 to 20 carbon atoms. , A halogen atom, —OH group, —COOH group, or a —COO-alkyl ester group having 1 to 20 carbon atoms. R ¹¹ and R ¹² may be different or the same.
In formula (8), X ⁻ represents PF ₆ ⁻ , AsF ₅ ⁻ , BF ₄ ⁻ , or a boronic acid represented by the following chemical formula (9).

Especially, what consists of a salt which uses the bulky boronic acid represented by the said Chemical formula (9) as a counter anion is suitable for the said cationic polymerization initiator. When a photocationic polymerization initiator having a counter anion represented by the above chemical formula (9) is used, the transparency is excellent, and oxidation of the electrode hardly occurs at the interface between the electrode of the liquid crystal panel and the adhesive of the present invention, and durability. Excellent.

Although it does not specifically limit as content of the said cationic polymerization initiator, A preferable minimum is 0.1 weight part and a preferable upper limit is 10 weight part with respect to 100 weight part of whole quantity of the said photocationic polymerizable compound. If the content of the cationic polymerization initiator is less than 0.1 parts by weight, the cationic polymerization of the photocationically polymerizable compound may not proceed sufficiently, or the curing reaction thereof may become too slow. When the content of the cationic polymerization initiator exceeds 10 parts by weight, the curing reaction of the photocationically polymerizable compound becomes too fast, and the workability may be lowered or the cured product may be uneven. The minimum with more preferable content of the said cationic polymerization initiator is 0.3 weight part, and a more preferable upper limit is 5 weight part.

The curing retarder has a structure represented by the general formula (1). By containing a curing retarder, the pod life is lengthened and the handleability is improved. In addition, since it is possible to perform bonding and the like after irradiating light once, it becomes possible to bond a member that is easily damaged by light. The curing retarder having the structure represented by the general formula (1) does not impair the transparency of the composition even when used in combination with the epoxy-modified silicone or the like.

Among the curing retarders having the structure represented by the general formula (1), those having at least one cyclohexyl group are preferable. By having a cyclohexyl group, compatibility with the silicone resin is improved and transparency is improved.
Specific examples of the curing retarder having a structure represented by the general formula (1) having a cyclohexyl group include those having a structure represented by the following formula (2).

The compound having the structure represented by the chemical formula (2) has two cyclohexyl groups at positions symmetrical with respect to a line passing through the center of the 18-crown-6-ether molecule. It is considered that the effect of improving the compatibility is increased without causing distortion or the like in the skeleton of the 6-ether molecule.

As content of the said hardening retarder, a preferable minimum is 0.05 weight part and a preferable upper limit is 5.0 weight part with respect to 100 weight part of said photocationic polymerizable compounds. If the content of the curing retarder is less than 0.05 parts by weight, the post-curing composition of the present invention may not be sufficiently imparted with a retarding effect, and if it exceeds 5.0 parts by weight, The outgas etc. which generate | occur | produce when hardening a photo post-curing composition increase, and it may become difficult to use the photo post curable composition of this invention for the use which this out gas has a big influence. The minimum with more preferable content of the said retarder is 0.1 weight part, and a more preferable upper limit is 3 weight part.

The photo post-curing composition of the present invention preferably contains a sensitizer comprising a benzophenone derivative represented by the following general formula (10). The said sensitizer improves the efficiency of the said photocationic polymerization initiator more, and accelerates | stimulates the hardening reaction of the photo after-curable composition of this invention more.

In formula (10), R ¹³ and R ¹⁴ represent hydrogen, the following general formula (11-1), and the following general formula (11-2). R ¹³ and R ¹⁴ may be different or the same.

In the formulas (11-1) and (11-2), R ¹⁵ represents hydrogen, a linear alkyl group having 1 to 20 carbon atoms, a branched alkyl group having 1 to 20 carbon atoms, or 1 carbon atom. Represents an alkoxyl group having 20 carbon atoms, a halogen atom, -OH group, -COOH group, or a -COO-alkyl ester group having 1 to 20 carbon atoms.

Specific examples of the sensitizer represented by the general formula (10) include benzophenone, 2,4-dichlorobenzophenone, methyl o-benzoylbenzoate, 4,4′-bis (dimethylamino) benzophenone, 4-benzoyl-4'methyldiphenyl sulfide is mentioned.

Although it does not specifically limit as content of the said sensitizer, A preferable minimum is 0.05 weight part and a preferable upper limit is 3 weight part with respect to 100 weight part of whole quantity of the said photocationic polymerizable compound. When the content of the sensitizer is less than 0.05 parts by weight, the sensitizing effect may be weak. If it exceeds 3 parts by weight, the absorption may be too great and light may not be transmitted to the deep part. The minimum with more preferable content of the said sensitizer is 0.1 weight part, and a more preferable upper limit is 1 weight part.

It is preferable that the photo post-curable composition of the present invention further contains a thermosetting agent.
By containing the said thermosetting agent, thermosetting property can be suitably provided to the optical post-curable composition of this invention.
The thermosetting agent is not particularly limited. For example, hydrazide compounds such as 1,3-bis [hydrazinocarbonoethyl-5-isopropylhydantoin], dicyandiamide, guanidine derivatives, 1-cyanoethyl-2-phenylimidazole, N -[2- (2-methyl-
1-imidazolyl) ethyl] urea, 2,4-diamino-6- [2′-methylimidazolyl- (1 ′)]-ethyl-s-triazine, N, N′-bis (2-methyl-1-imidazolylethyl) ) Imidazole derivatives such as urea, N, N ′-(2-methyl-1-imidazolylethyl) -adipamide, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole And acid anhydrides such as modified aliphatic polyamines, tetrahydrophthalic anhydride, ethylene glycol-bis (anhydrotrimellitate), addition products of various amines and epoxy resins, and the like. These may be used alone or in combination of two or more.

When the thermosetting agent is contained, the content is not particularly limited, but the preferred lower limit is 0.5 parts by weight and the preferred upper limit is 30 parts by weight with respect to a total of 100 parts by weight of the photocationically polymerizable compound. is there. If the content of the thermosetting agent is less than 0.5 parts by weight, sufficient photocurability may not be imparted to the photo-curable composition of the present invention, and if it exceeds 30 parts by weight, The storage stability of the photo post-curable composition may become unstable, and the moisture resistance of the cured product of the photo post-curable composition of the present invention may be insufficient. The minimum with more preferable content of the said thermosetting agent is 1 weight part, and a more preferable upper limit is 15 weight part.

The photo post-curable composition of the present invention preferably further contains a silane coupling agent. By containing a silane coupling agent, the adhesiveness with a liquid crystal panel, a board | substrate, etc. improves.

Specific examples of the silane coupling agent include γ-aminopropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, and γ-isocyanatopropyltrimethoxysilane. Can be mentioned. These silane compounds may be used alone or in combination of two or more.

The blending ratio of the silane coupling agent is not particularly limited, but a preferred lower limit is 0.1 parts by weight and a preferred upper limit is 10 parts by weight with respect to a total of 100 parts by weight of the photocationically polymerizable compound. If the blending ratio of the silane coupling agent is less than 0.1 parts by weight, the effect of adding the silane coupling agent may hardly be obtained, and if it exceeds 10 parts by weight, an excess silane coupling agent May bleed out. The minimum with a more preferable mixture ratio of the said silane coupling agent is 0.5 weight part, and a more preferable upper limit is 5 weight part.

The photo post-curable composition of the present invention may contain a filler as long as the transparency is not impaired.
The filler is not particularly limited, for example, talc, asbestos, silica, diatomaceous earth, smectite, bentonite, calcium carbonate, magnesium carbonate, alumina, montmorillonite, diatomaceous earth, magnesium oxide, titanium oxide, magnesium hydroxide, aluminum hydroxide, Examples include inorganic fillers such as glass beads, barium sulfate, gypsum, calcium silicate, talc, glass beads, sericite activated clay and bentonite, and organic fillers such as polyester fine particles, polyurethane fine particles, vinyl polymer fine particles, and acrylic polymer fine particles. .

The light post-curable composition of the present invention preferably has a light transmittance of 90% or more in the visible light region when the cured product has a thickness of 100 μm. If it is less than 90%, the transparency of the cured adhesive of the present invention may be insufficient.
The post-photocurable composition of the present invention preferably has a haze of 5% or less when the cured product has a thickness of 100 μm.

The method for producing the photo post-curable composition of the present invention is not particularly limited. For example, the epoxy-modified silicone is used by using a mixer such as a homodisper, a homomixer, a universal mixer, a planetarium mixer, a kneader, or a three roll. Or the method of mixing an oxetane modified silicone, a cation polymerizable monomer, a photocationic polymerization initiator, a hardening retarder, and the additive added as needed is mentioned.

The curable composition for optical components of the present invention is suitably used for applications such as a sealing agent for organic EL elements, an adhesive for bonding a liquid crystal panel of a liquid crystal display device and a transparent member, and the like. it can.

ADVANTAGE OF THE INVENTION According to this invention, the outstanding adhesiveness can be maintained irrespective of use environment temperature change, it can be excellent in transparency, and the photo curable composition with a long pod life can be provided.

Hereinafter, embodiments of the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.

(Examples 1-7, Comparative Examples 1-3)
According to the composition shown in Table 1, an epoxy-modified silicone or oxetane-modified silicone, a cationic polymerizable monomer, a cationic polymerization initiator, a curing retarder, and a silane coupling agent were mixed to prepare a photo post-curing composition. .
In addition, the manufacturing company name etc. of each material which concerns on the Example and comparative example which were shown in Table 1 are as follows.

(Epoxy modified silicone)
Albiflex 348 (Nanoresin)

(Oxetane modified silicone)
Aron Oxetane OX-SC (Toagosei Co., Ltd.)

(Cationically polymerizable monomer)
X-22-169AS (manufactured by Shin-Etsu Silicone)

(Cationic polymerization initiator)
RP-2074 (iodonium salt, manufactured by Midori Chemical Co., Ltd.)

(Silane coupling agent)
KBM-403 (manufactured by Shin-Etsu Chemical)

(Evaluation)
The following evaluation was performed about the photo-curable composition prepared in the Example and the comparative example. The results are shown in Table 1.

(1) The storage elastic modulus glass substrate was poured into the optical post-curable compositions prepared in Examples and Comparative Examples to a thickness of about 1 mm, and irradiated with 1500 mJ with an ultraviolet lamp. Then, it heated at 80 degreeC for 10 minute (s), reaction was completed, and the hardening body of the photo after-curing composition which concerns on an Example and a comparative example was produced.
Using the EI measurement viscoelasticity spectrometer (DVA-200, manufactured by IT Measurement & Control Co., Ltd.), the cured product was tensile elastic in the temperature range of −60 to 120 ° C., under the condition of a frequency of 10 cycles / second. The storage modulus was measured.

(2) Optical characteristics (light transmittance)
The space between the alkali glass having a thickness of 1 mm is kept at 100 μm, and the photo-curable compositions prepared in Examples and Comparative Examples are poured into the glass. After irradiation with ultraviolet rays of 1500 mJ, the glass is held at 80 ° C. for 10 minutes and after light. The curable composition was cured, and samples according to Examples and Comparative Examples were prepared.
Using the obtained sample, the absorbance at wavelengths of 400 nm, 550 nm and 780 nm was measured using a spectrophotometer (manufactured by Hitachi, Ltd., U-3000, conditions 300 to 800 nm), and the initial light transmittance was calculated. .

(Haze)
Using the sample used for the measurement of the light transmittance, haze was measured with a haze meter (TC-H3DPK manufactured by Tokyo Denshoku Co., Ltd.).

(3) Workable time The photo-curable compositions obtained in Examples and Comparative Examples were irradiated with 2000 mJ / cm ² of ultraviolet rays using an ultraviolet lamp (Spot Cure SP-7, manufactured by USHIO INC.). The viscosity was measured over time using a viscometer (manufactured by Toki Sangyo Co., Ltd., TV-22). The time for the viscosity to reach twice the initial value was defined as the pot life.

ADVANTAGE OF THE INVENTION According to this invention, the outstanding adhesiveness can be maintained irrespective of a use environment temperature change, it can be excellent in transparency, and the photo post-curable composition with a long pot life can be provided.

Claims (5)

Light containing epoxy-modified silicone and / or oxetane-modified silicone, cationic polymerizable monomer, photocationic polymerization initiator, and curing retarder having a structure represented by the following general formula (1) Post-curing composition.

In formula (1), at least one of R ^{21 to} R ³² represents an alkyl group having 1 to 20 carbon atoms, and the remainder represents hydrogen. The alkyl group is a linear or branched alkoxy group having 1 to 20 carbon atoms, halogen atom, —OH group, —COOH group, and —COO-alkyl ester group (provided that the alkyl moiety is linear Or may be substituted with one or more functional groups selected from the group consisting of branched-chain C1-20 residues, and adjacent R ⁿ and R ^{n + 1} (where n is , Each representing an odd number of 1 to 11) may form a cyclic alkyl skeleton. The post-curing composition according to claim 1, wherein the curing retardant has at least one cyclohexyl group. The post-curing composition according to claim 2, wherein the curing retarder has a structure represented by the following formula (2).

An adhesive for optical parts, comprising the photocurable composition according to claim 1, 2 or 3. A sealing agent for organic EL elements, comprising the photocurable composition according to claim 1, 2 or 3.