Photocurable silicone composition and cured product thereof

Abstract

A photocurable silicone composition is disclosed. A cured product of the composition is also disclosed. The photocurable silicone composition includes: (A) an organopolysiloxane having at least one aryl group having 6 to 12 carbon atoms and at least one alkenyl group having 2 to 12 carbon atoms per molecule; (B) an organic compound having at least two ether bonds and at least one aliphatic carbon-carbon double bond per molecule; (C) a thiol group-containing organic compound, the thiol group-containing organic compound including (C1) an organic compound having two thiol groups per molecule and (C2) an organic compound having at least three thiol groups per molecule; and (D) a photoradical initiator. The composition generally inhibits cracking and delamination of a cured product laminated between two substrates after heat aging.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to and all benefits of U.S. Provisional Patent Application No. 62 / 939,640, filed November 24, 2019, the contents of which are incorporated herein by reference.

[0002] The present invention relates to a photocurable silicone composition and a cured product thereof. [Background technology]

[0003] Patent Document 1 proposes a photocurable silicone composition that includes an organopolysiloxane having at least one aryl group having 6 to 12 carbon atoms and at least one alkenyl group having 2 to 12 carbon atoms in the molecule, an organic compound having at least two ether bonds and at least one aliphatic carbon-carbon double bond in the molecule, a compound having at least two thiol groups in the molecule, a photoradical initiator having a phosphorus atom, and a hindered phenol compound. The photocurable silicone composition is cured by irradiation with active energy rays to form a cured product that suppresses the decrease in transmittance due to coloring and haze even when left under high temperature / high humidity conditions.

[0004] However, such photocurable silicone compositions have the problem that after heat aging, the cured product cracks or delaminates from substrates that it comes into contact with during curing.

[0005] [Cited documents] / [Patent documents] Patent Document 1: International Publication No. 2017 / 155919(A1) Summary of the Invention

[0006] [Technical issues] An object of the present invention is to provide a photocurable silicone composition that inhibits cracking and peeling of the cured product in an optical device or image display.

[0007] [Problem Solution] The photocurable silicone composition of the present invention comprises: (A) 100 parts by mass of an organopolysiloxane having at least one aryl group having 6 to 12 carbon atoms and at least one alkenyl group having 2 to 12 carbon atoms in the molecule; (B) 1 to 50 parts by mass of an organic compound having at least two ether bonds and at least one aliphatic carbon-carbon double bond in the molecule; (C) a thiol group-containing organic compound, (C1) an organic compound having two thiol groups in the molecule, and (C2) 4 to 40 parts by mass of a thiol group-containing organic compound including an organic compound having at least three thiol groups in the molecule; (D) 0.05 to 2 parts by mass of a photoradical initiator.

[0008] In various embodiments, component (A) has the average formula: R 1 a R 2 b SiO (4-a-b) / 2 The organopolysiloxane is represented by the following formula:

[0009] In the formula, R 1 is an alkenyl group having 2 to 12 carbon atoms, R 2 is an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an aralkyl group having 7 to 12 carbon atoms, provided that R 2 At least 30 mol % of the above groups are aryl groups or aralkyl groups, and "a" and "b" are positive numbers satisfying 1≦a+b≦2.5 and 0.001≦a / (a+b)≦0.2.

[0010] In various embodiments, component (B) is an organic compound having at least two ether bonds and at least one acryloyl or methacryloyl group in the molecule.

[0011] In various embodiments, the molar ratio of component (C1) to component (C2) in component (C) ranges from 0.45 to 2.8.

[0012] In various embodiments, component (D) is a photoradical initiator having a phosphorus atom.

[0013] In various embodiments, the photocurable silicone composition further comprises (E) a hindered phenol compound in an amount of 0.001 to 1 part by weight per 100 parts by weight of component (A).

[0014] In various embodiments, the photocurable silicone composition further comprises (F) a radical scavenger other than component (E) in an amount of 0.0001 to 1 part by weight per 100 parts by weight of component (A).

[0015] In various embodiments, the photocurable silicone composition further comprises (G) an adhesion promoter in an amount of up to 10 parts by weight per 100 parts by weight of component (A).

[0016] The cured product of the present invention can be obtained by irradiating the above-described photocurable silicone composition with light.

[0017] [Effects of the invention] The photocurable silicone composition of the present invention is cured by irradiation with active energy rays to form a cured product that is inhibited from cracking or peeling after thermal aging, even when the photocurable silicone composition is laminated between two substrates and cured.

[0018] The cured product of the present invention exhibits excellent crack resistance and adhesion. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] The terms "comprising" or "comprise" are used herein in their broadest sense to mean and encompass the ideas of "including," "include," "consist(ing) essentially of," and "consist(ing) of." The use of "for example," "eg," "such as," and "including" to list examples does not limit the examples listed. Thus, "for example" or "such as" means "for example, but not limited to" or "such as, but not limited to," and includes other similar or equivalent examples. As used herein, the term "about" serves to reasonably encompass or account for slight variations in numerical values ​​as determined by instrumental analysis or as a result of handling samples. Such slight variations may be on the order of ±0-25%, ±0-10%, ±0-5%, or ±0-2.5% of the numerical value. Furthermore, the term "about" applies to both numerical values ​​when relating to a range of values. Furthermore, the term "about" may apply to numerical values ​​even if not expressly stated.

[0020] Generally, as used herein, a hyphen "-" or a wavy line "~" in a range of values ​​means "to" or "through," ">" means "above" or "greater-than," "≥" means "at least" or "greater-than or equal to," "<" means "below" or "less-than," and "≤" means "at most" or "less-than or equal to." Each of the foregoing patent applications, patents, and / or patent publications is expressly incorporated herein in its entirety in one or more non-limiting embodiments on an individual basis.

[0021] It should be understood that the appended claims are not limited to the expressions and specific compounds, compositions, or methods described in the detailed description, which may vary among the specific embodiments within the scope of the appended claims. With respect to any Markush group relied upon herein to describe particular features or aspects of various embodiments, it should be understood that different, special, and / or unexpected results may be obtained from each element of the respective Markush group independently of all other Markush elements. Each element of the Markush group may be relied upon individually and / or in combination to provide appropriate support for specific embodiments within the scope of the appended claims.

[0022] Any ranges and subranges relied upon in describing various embodiments of the present invention should also be understood to be within the scope of the appended claims, both individually and inclusively, and all ranges including integer and / or fractional values ​​therein are understood to be described and contemplated, even if such values ​​are not expressly written herein. Those skilled in the art will readily recognize that the recited ranges and subranges fully describe and enable various embodiments of the present invention, and that such ranges and subranges may be further delineated into relevant halves, thirds, fourths, fifths, etc. As merely an example, the range "0.1-0.9" may be further delineated into a lower third, i.e., 0.1-0.3, a middle third, i.e., 0.4-0.6, and an upper third, i.e., 0.7-0.9, which are individually and inclusively within the scope of the appended claims, and may be relied upon and provide sufficient support for specific embodiments within the scope of the appended claims, individually and / or inclusively. Furthermore, with respect to words defining or modifying a range, such as "at least," "greater than," "less than," "less than," etc., such words should be understood to include subranges and / or upper or lower limits. As another example, the range "at least 10" inherently includes the subranges of at least 10 to 35, at least 10 to 25, 25 to 35, etc., and each subrange may be relied upon and fully supported by specific embodiments within the appended claims, individually and / or collectively. Finally, each individual number within a disclosed range may be relied upon and fully supported by specific embodiments within the appended claims. For example, the range "1 to 9" includes various individual integers, such as 3, as well as individual numbers including decimal points (or fractions), such as 4.1, which may be relied upon and fully supported by specific embodiments within the appended claims.

[0023] <Photocurable silicone composition> Component (A) is the base compound of the present composition and is an organopolysiloxane having at least one aryl group having 6 to 12 carbon atoms and at least one alkenyl group having 2 to 12 carbon atoms in the molecule.

[0024] Examples of aryl groups include phenyl, tolyl, xylyl, and naphthyl groups, with phenyl groups being preferred in various embodiments from an economical standpoint.

[0025] Examples of alkenyl groups include vinyl, allyl, isopropenyl, butenyl, pentenyl, hexenyl, heptenyl, cyclohexenyl, octenyl, nonenyl, decenyl, undecenyl, and dodecenyl groups. In various embodiments, vinyl, allyl, hexenyl, and octenyl groups may be desirable from the standpoint of economy and reactivity.

[0026] Examples of groups bonded to silicon atoms other than aryl and alkenyl groups in component (A) include alkyl groups having 1 to 12 carbon atoms, such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, and octyl; aralkyl groups having 7 to 20 carbon atoms, such as benzyl, phenethyl, and 3-phenylpropyl; and halogenated alkyl groups having 1 to 12 carbon atoms, such as chloromethyl, 3-chloropropyl, 3,3,3-trifluoropropyl, and nonafluorobutylethyl. In various embodiments, methyl groups may be desirable from the standpoint of economic efficiency. Additionally, silicon atoms in component (A) may be bonded to small amounts of hydroxyl or alkoxy groups, such as methoxy, ethoxy, n-propoxy, i-propoxy, n-butoxy, sec-butoxy, and tert-butoxy groups.

[0027] Component (A) preferably has the average formula: R 1 a R 2 b SiO (4-a-b) / 2 The organopolysiloxane is represented by the following formula:

[0028] In the formula, R 1is an alkenyl group having 2 to 12 carbon atoms, examples of which include a vinyl group, an allyl group, a butenyl group, a pentenyl group, a hexenyl group, a heptenyl group, an octenyl group, a nonenyl group, a decenyl group, an undecenyl group, and a dodecenyl group. Among these, a vinyl group and a hexenyl group are preferred.

[0029] In the formula, R 2 is an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an aralkyl group having 7 to 12 carbon atoms. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a isopropyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, an undecyl group, and a dodecyl group. Of these, a methyl group is preferred. Examples of the aryl group include a phenyl group, a tolyl group, a naphthyl group, and a biphenyl group. Of these, a phenyl group is preferred. Examples of the aralkyl group include a phenylmethyl group, a 1-phenylethyl group, a 2-phenylethyl group, and a 2-phenylpropyl group. Of these, a 2-phenylethyl group and a 2-phenylpropyl group are preferred. In component (A), when R 2 At least 30 mol % of the groups are aryl or aralkyl groups.

[0030] Furthermore, in the formula, "a" and "b" are positive numbers satisfying 1≦a+b≦2.5, preferably 1.5≦a+b≦2.2, and 0.001≦a / (a+b)≦0.2, preferably 0.005≦a / (a+b)≦0.1.

[0031] The state of component (A) at 25° C. is not limited, but it is preferably a liquid. The viscosity of component (A) at 25° C. is not limited, but the viscosity is preferably within the range of 100 to 1,000,000 mPa·s.

[0032] Component (A) may be one organopolysiloxane satisfying the above average compositional formula, or may be a mixture of at least two organopolysiloxanes satisfying the above average compositional formula. Examples of such component (A) include organopolysiloxanes represented by the following "average compositional formula: average formula". In the formula, "Me", "Vi", "Hex", "Ph", "Phe", and "Php" respectively represent methyl, vinyl, hexenyl, phenyl, 2-phenylethyl, and 2-phenylpropyl groups. Vi 0.03 Me 1.03 Ph 0.97 SiO 0.99 :ViMe2SiO(MePhSiO) 65 SiMe2Vi Vi 0.10 Me 1.10 Ph 0.90 SiO 0.95 :ViMe2SiO(MePhSiO) 18.4 SiMe2Vi Vi 0.09 Me 1.06 Ph 0.91 SiO 0.97 :PhSi{O(PhMeSiO) 10 SiMe2Vi}3 Hex 0.09 Me 1.07 Ph 0.89 SiO 0.98 :Si{O(PhMeSiO) 10 SiMe2Hex}4 Hex 0.12 Me 1.12 Ph 0.88 SiO 0.94 :HexMe2SiO(PhMeSiO) 15 SiMe2Hex Vi 0.06 Me 1.38 Phe 0.63 SiO 0.97 :ViMe2SiO(PheMeSiO) 20 (Me2SiO) 10 SiMe2Vi Hex 0.06 Me 1.38 Php 0.63 SiO0.97 :HexMe2SiO(PhpMeSiO) 20 (Me2SiO) 10 SiMe2Hex

[0033] Component (B) is a second base compound of the composition, and is an organic compound having at least two ether bonds and at least one aliphatic carbon-carbon double bond in the molecule. The group having an aliphatic carbon-carbon double bond in component (B) is not limited, and examples thereof include an alkenyl group, an acryloyl group, and a methacryloyl group. Among them, an acryloyl group or a methacryloyl group is preferred. Furthermore, the state of component (B) at 25°C is not limited, and is preferably a liquid. The viscosity of component (B) at 25°C is not limited, but the viscosity is preferably within the range of 1 to 10,000 mPa·s.

[0034] Examples of such component (B) include phenoxydiethylene glycol acrylate, phenoxytetraethylene glycol acrylate, methoxytriethylene glycol acrylate, methoxynonaethylene glycol acrylate, methoxypolyethylene glycol acrylate, ethoxydiethylene glycol acrylate, ethoxyethoxyethyl acrylate, nonylphenoxytetraethylene glycol acrylate, nonylphenoxyoctaethylene glycol acrylate, nonylphenoxydipropylene glycol acrylate, methoxydiethylene glycol methacrylate, methoxypolyethylene glycol methacrylate, polyethylene glycol methacrylate, triethylene glycol diacrylate, polyethylene glycol diacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, polypropylene glycol diacrylate, bisphenol diethylene glycol diacrylate, bisphenol A triethylene glycol diacrylate, tetraethylene glycol diacrylate, bis Phenol A polyethylene glycol diacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, polypropylene glycol dimethacrylate, bisphenol A diethylene glycol dimethacrylate, bisphenol A triethylene glycol dimethacrylate, bisphenol A tetraethylene glycol dimethacrylate, bisphenol A polyethylene glycol dimethacrylate, triethylene glycol divinyl ether, tripropylene glycol divinyl ether, polyethylene glycol monoallyl ether, methoxypolyethylene glycol allyl ether, propylene glycol allyl ether, butoxypolyethylene glycol / propylene glycol allyl ether, polyethylene glycol diallyl ether, polypropylene glycol diallyl ether, trimethylolpropane triallyl ether, trimethylolpropane diallyl ether, pentaerythritol tetraallyl ether, and pentaerythritol triallyl ether.

[0035] The content of component (B) is within the range of 1 to 50 parts by mass, optionally within the range of 5 to 40 parts by mass, optionally within the range of 5 to 40 parts by mass, or optionally within the range of 10 to 40 parts by mass per 100 parts by mass of component (A). This is because when the content of component (B) is equal to or higher than the lower limit of the above range, the decrease in transmittance of the cured product at high temperature / high humidity is small. On the other hand, when the content is equal to or lower than the upper limit of the above range, the change in hardness of the cured product at high temperature is small, and coloring is reduced.

[0036] Component (C) is a curing agent for the composition and is a thiol group-containing organic compound including (C1) an organic compound having two thiol groups in its molecule, and (C2) an organic compound having at least three thiol groups in its molecule.

[0037] Component (C1) is an organic compound having two thiol groups in the molecule. Component (C1) is not limited as long as the organic compound has sufficient solubility in component (A) and / or component (B). Examples of such component (C1) include o-, m-, or p-xylenedithiol, ethylene glycol bisthioglycolate, butanediol bisthioglycolate, hexanediol bisthioglycolate, ethylene glycol bis(3-thiopropionate), butanediol bis(3-thiopropionate), and organopolysiloxane substituted with a mercapto group.

[0038] Component (C2) is an organic compound having at least three thiol groups in the molecule. Component (C2) is not limited as long as the organic compound has sufficient solubility in component (A) and / or component (B). Examples of such component (C2) include trimethylolpropane tris(3-thiopropionate), pentaerythritol tetrakis(3-thiopropionate), trihydroxyethyl triisocyanurate tris(3-thiopropionate), and organopolysiloxane substituted with a mercapto group.

[0039] The molar ratio of component (C1) to component (C2) in component (C) is preferably within the range of 0.45 to 2.8, optionally within the range of 0.5 to 2.8, optionally within the range of 0.6 to 2.8, optionally within the range of 0.5 to 2.6, optionally within the range of 0.5 to 2.5, or optionally within the range of 0.6 to 2.4. This is because when the molar ratio of component (C1) to component (C2) in component (C) is equal to or greater than the lower limit of the above range, the decrease in transmittance of the cured product at high temperature / high humidity is small. On the other hand, when the molar ratio of component (C1) to component (C2) in component (C) is equal to or less than the upper limit of the above range, the change in hardness of the cured product at high temperature is small, and coloring is reduced.

[0040] Examples of such components (C) include o-, m-, or p-xylenedithiol, ethylene glycol bisthioglycolate, butanediol bisthioglycolate, Examples of the thioglycolate include hexanediol bisthioglycolate, ethylene glycol bis(3-thiopropionate), butanediol bis(3-thiopropionate), trimethylolpropane tris(3-thiopropionate), pentaerythritol tetrakis(3-thiopropionate), trihydroxyethyl triisocyanurate tris(3-thiopropionate), and organopolysiloxanes substituted with mercapto groups.

[0041] The content of component (C) is within the range of 4 to 40 parts by mass, optionally within the range of 5 to 30 parts by mass, or optionally within the range of 5 to 20 parts by mass per 100 parts by mass of component (A). The content of component (C) is such that the amount of thiol groups provided by this component is within the range of 0.2 to 2.0 mol, optionally within the range of 0.3 to 1.6 mol, or optionally within the range of 0.5 to 1.5 mol per 1 mol of all aliphatic carbon-carbon double bonds in components (A) and (B) of the composition. This is because when the content of component (C) is within the above range, the mechanical strength of the obtained cured product is increased.

[0042] Component (D) is a component for initiating the photocuring reaction of the present composition. Component (D) is not limited, but is preferably a photoradical initiator containing a phosphorus atom. Examples of such component (D) include diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide (trade name: TPO, manufactured by BASF), ethyl (2,4,6-trimethylbenzoyl) phenylphosphonate (trade name: TPO-L, manufactured by BASF), and phenylbis (2,4,6-trimethylbenzoyl) phosphine oxide (trade name: Irgacure 819, manufactured by BASF).

[0043] The content of component (D) is within the range of 0.05 to 2 parts by mass, optionally within the range of 0.05 to 1 part by mass, or optionally within the range of 0.1 to 0.8 parts by mass per 100 parts by mass of component (A), because when the content of component (D) is within the above range, curing proceeds efficiently and a cured product having excellent heat resistance and light resistance is formed.

[0044] The composition contains the above-mentioned components (A) to (D), and in order to improve the heat resistance of the cured product of the composition, it is preferable to contain a hindered phenol compound (E). Examples of such component (E) include pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], thiodiethylene bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 2,4-dimethyl-6-(1-methylpentadecyl)phenol, diethyl[{3,5-bis(1,1-di-tert-butyl-4-hydroxyphenyl)methyl}phosphonate, 3,4-dimethyl-6-(1-methylpentadecyl)phenol, ... 3′,3″,5,5′,5″-hexane-tert-butyl-4-a,a′,a″-(mesitylene-2,4,6-tolyl)tri-p-cresol, 4,6-bis(octylthiomethyl)-o-cresol, ethylene bis(oxyethylene) bis[3-(5-tert-butyl-4-hydroxy-m-tolyl)propionate], and hexamethylene bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate].

[0045] The content of component (E) is not limited, but the content is preferably within the range of 0.001 to 1 part by mass, or optionally within the range of 0.003 to 0.5 parts by mass, per 100 parts by mass of component (A). This is because, when the content of component (E) is within the above range, the viscosity change of the composition before photocuring is small, and a cured product having excellent heat resistance and light resistance can be obtained.

[0046] The present composition contains the above-mentioned components (A) to (E), but in order to improve the storage stability of the present composition in a light-shielded state, it is preferable to contain (F) a radical scavenger other than component (E). Examples of such component (F) include hindered amines such as N,N',N'',N'''-tetrakis(4,6-bis(butyl-(N-methyl-2,2,6,6-tetramethylpiperidin-4-yl)amino)-triazin-2-yl)-4,7-diazadecane-1,10-diamine, bis(1,2,2,6,6-pentamethyl-4-piperidyl)[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]butylmalonate, and methyl-1,2,2,6,6-pentamethyl-4-piperidine. lysyl sebacate, bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, and 8-acetyl-3-dodecyl-7,7,9,9-tetramethyl-1,3,8-triazaspiro[4.5]decane-2,4-dione; quinones or phenols such as methylhydroquinone, 1,4-naphthoquinone, 4-methoxynaphthol, tert-butylhydroquinone, benzoquinone, pyrogallol, and phenothiazine.

[0047] The content of component (F) is not limited, but the content is preferably within the range of 0.0001 to 1 part by mass, optionally within the range of 0.0001 to 0.1 part by mass, or optionally within the range of 0.0001 to 0.05 part by mass per 100 parts by mass of component (A). This is because when the content of component (F) is within the above range, a cured product having excellent heat resistance and light resistance can be obtained.

[0048] The present composition may further contain an adhesion promoter (G) as an optional component, so long as the object of the present invention is not impaired.

[0049] Examples of component (G) include silane compounds such as 3-glycidoxypropyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and 3-methacryloxypropyltrimethoxysilane; siloxane compounds having at least one silicon-bonded alkenyl group and / or silicon-bonded hydrogen atom, and at least one silicon-bonded alkoxy group in the molecule; silane compounds or siloxane compounds having at least one silicon-bonded alkoxy group, A mixture of a siloxane compound having at least one silicon-bonded hydroxy group and at least one silicon-bonded alkenyl group in the molecule; methyl polysilicate, ethyl polysilicate, and epoxy group-containing ethyl polysilicate are included. The content of the tackifier is not limited, but the content is preferably within the range of 0.01 to 10 parts by mass per 100 parts by mass of component (A).

[0050] The present composition may further contain, as an optional component, (H) a UV absorber other than the above component (D), so long as the object of the present invention is not impaired.

[0051] Examples of such components (H) include substituted and unsubstituted benzophenones, benzotriazoles, cyanoacrylates, and hydroxyphenyltriazines. For example, suitable UV absorbers include various hydroxybenzophenones, hydroxyphenyltriazines (HPT), and hydroxybenzotriazoles. Preferred UV absorbers include compounds sold under the trade name TINUVIN® by BASF (Florham Park, New Jersey), including TINUVIN® 384-2 (liquid hydroxybenzotriazole UV absorbing compound), TINUVIN® 479 (hydroxyphenyltriazine UV absorbing compound) and TINUVIN® 400 (liquid hydroxyphenyltriazine (HPT) UV absorbing compound). Other suitable UV absorbers that can be utilized are disclosed, for example, in U.S. Patent Application Publication No. 2006 / 0007519(A1), the disclosure of which is incorporated herein by reference.

[0052] The content of component (H) is not limited, but the content is preferably 2 parts by mass or less, or optionally 1 part by mass or less, per 100 parts by mass of component (A).

[0053] In addition to the above components (A) and (B), the present composition may further contain, as optional components, an organic compound having at least one aliphatic carbon-carbon double bond in the molecule; an inorganic filler, for example, silica, titanium oxide, glass, alumina, or zinc oxide; a fine powder of an organic resin, such as a polymethacrylate resin or a silicone resin; and a pigment or a fluorescent substance, so long as the object of the present invention is not impaired.

[0054] Examples of such organic compounds include methyl acrylate, methyl methacrylate, butyl acrylate, butyl methacrylate, isobornyl acrylate, isobornyl methacrylate, isooctyl acrylate, lauryl acrylate, stearyl acrylate, isodecyl acrylate, triacrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, methoxyethyl acrylate, methoxyethyl methacrylate, phenoxyethyl acrylate, tetrahydrofuran acrylate, benzyl acrylate, o- Phenylphenol ethoxyethyl acrylate, 2-ethylhexyl acrylate, hexanediol diacrylate, nonanediol diacrylate, 2-propenoic acid octahydro-4,7-methano-1H-inden-5-yl ester, decyl vinyl ether, 2-ethylhexyl vinyl ether, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, allyl methacrylate, divinyl sulfone, 3-methacryloxypropyltrimethoxysilane, and 3-acryloxypropyltrimethoxysilane.

[0055] The viscosity of the composition at 25°C is not limited, but is preferably within the range of 100 to 100,000 mPa·s, or optionally within the range of 500 to 10,000 mPa·s. This is because when the viscosity of the composition is equal to or higher than the lower limit of the above range, a cured product having high mechanical strength is obtained. On the other hand, when the viscosity is equal to or lower than the upper limit of the above range, the coating property / workability of the obtained composition is excellent, and the formation of voids in the cured product is avoided.

[0056] The composition is useful as a variety of potting agents, sealants, and adhesives. The cured product is less colored and less prone to haze at high temperatures or under high temperature / high humidity conditions, making the composition suitable as a material for forming an intermediate layer between an image display section and a protective section of an image display device.

[0057] <Cured product> The cured product of the present invention can be obtained by irradiating the above-mentioned photocurable silicone composition with light. Examples of light used to cure the composition include ultraviolet light and visible light, and light having a wavelength in the range of 250 to 500 nm is preferred. This is because excellent curability can be obtained and the cured product is not decomposed by light.

[0058] The cured product is typically optically transparent. This is because optical transparency is desirable for high performance when the cured product is preferably used in an optical device or image display. The form of the cured product is not limited and can be in the form of a sheet, film, or block. The cured product can be combined with various substrates. The cured product is typically laminated between the same substrate or different substrates, particularly between the same substrate or different substrates in an optical device.

[0059] The state of the cured product is not limited, but is preferably an elastomer or a gel. The hardness of the cured product is preferably in the range of 0 to 80, or optionally in the range of 10 to 70, in Shore OO hardness. On the other hand, the penetration of the cured product is preferably in the range of 0 to 100, or optionally in the range of 10 to 70. This is because, when the cured product is within the above range, good cohesive force against deformation and good flexibility against material crushing are obtained. In this specification, the Shore OO hardness is a value measured at 23±2°C using OO hardness according to ASTM D 2240. On the other hand, the penetration is a value measured using the penetration specified with a 1 / 4 cone according to JIS K 2220.

[0060] The cured product is useful as a laminate in an optical device or image display. The optical device is, for example, an optical semiconductor device. Examples of optical semiconductor devices include light-emitting diodes (LEDs), photocouplers, and CCDs. Furthermore, as optical semiconductor elements, light-emitting diode (LED) elements and solid-state image sensors are shown. In particular, even when so-called micro LEDs (mini LEDs) having a structure in which a large number of small LED elements are arranged on a substrate are collectively sealed, the photocurable silicone composition of the present invention can be suitably used. At this time, the refractive index of the cured product can be adjusted as necessary by selecting the type of functional group, such as the content of aryl groups. Furthermore, since the photocurable silicone composition of the present invention has excellent heat resistance and moisture resistance, the transparency is unlikely to decrease and turbidity is hardly caused. Therefore, there is an advantage that the light extraction efficiency of an optical semiconductor device including a micro LED can be well maintained. EXAMPLES

[0061] The photocurable silicone composition of the present invention and its cured product will be described in detail using examples and comparative examples. In the formulas, "Me", "Ph", and "Vi" respectively represent a methyl group, a phenyl group, and a vinyl group. The properties of the cured product of the photocurable silicone composition were measured as follows.

[0062] <Appearance of the cured product> The photocurable silicone composition was filled into a mold having a recess of a predetermined shape, and the cumulative radiation was 4000 mJ / cm 2 The liquid was irradiated with ultraviolet light from above using a 405 nm UV-LED lamp so that the liquid surface ...

[0063] <Penetration of cured product> The photocurable silicone composition was filled into a mold having a recess of a predetermined shape, and the cumulative radiation was 4000 mJ / cm 2 The liquid was irradiated with ultraviolet light from a 405 nm UV-LED lamp from above the liquid surface so that the penetration of the cured product was measured using the penetration specified with a 1 / 4 cone in accordance with JIS K 2220.

[0064] <Lap shear elongation and strength of the cured product> The photocurable silicone composition was poured between two glass substrates measuring 25 mm long x 75 mm wide x 2 mm thick to create a bonding area of ​​25 mm long x 25 mm wide x 0.2 mm thick, and the cumulative radiation was 4000 mJ / cm 2 The glass surface above was irradiated with ultraviolet light using a 405 nm UV-LED lamp so that the cured product was lap shear strength measured in accordance with JIS K 6850. At the same time, the lap shear elongation was expressed as a percentage of the thickness of the cured product relative to the deformation at the break point.

[0065] <Appearance of laminated panel after heat aging test> The photocurable silicone composition was filled between a glass substrate measuring 165 mm in length, 105 mm in width, and 2 mm in thickness and a PMMA-coated PC substrate measuring 210 mm in length, 160 mm in width, and 1 mm in thickness to produce a cured product measuring 165 mm in length, 85 mm in width, and 0.13 mm in thickness. The laminate was then subjected to a cumulative radiation of 4000 mJ / cm 2 The upper glass surface was irradiated with ultraviolet light using a 405 nm UV-LED lamp so that the cured laminate was heat aged at 90° C. for 24 hours, and its appearance was visually confirmed.

[0066] <Examples 1 to 5 and Comparative Examples 1 to 8> The photocurable silicone compositions of Examples 1 to 5 and Comparative Examples 1 to 8 were prepared by uniformly mixing the following components according to the compositions (parts by mass) shown in Tables 1 to 5. In the formulas, "Me", "Vi", "Ph", and "Ep" represent a methyl group, a vinyl group, a phenyl group, and a 3-glycidoxypropyl group, respectively. In Table 1, "(c1) / (c2)" represents the number of moles of component (c1) per mole of component (c2) in the photocurable silicone composition. Furthermore, in Table 1, "SH / C=C" represents the number of moles of thiol groups in component (C) per mole of aliphatic saturated carbon-carbon double bonds in components (A) and (B) in the photocurable silicone composition. The properties of the photocurable silicone compositions and their cured products are shown in Table 1.

[0067] The following organopolysiloxanes were used as component (A): (a1) having a viscosity of 2000 mPa s and the following average formula: ViMe2SiO(MePhSiO) 18.4 SiMe2Vi (Average composition formula: Vi 0.10 Me 1.10 Ph 0.90 SiO 0.95 ) Organopolysiloxane represented by the formula:

[0068] (a2) having a viscosity of 40,000 mPa s and the following average formula: ViMe2SiO(MePhSiO) 65 SiMe2Vi (Average composition formula: Vi 0.03 Me 1.03 Ph 0.97 SiO 0.99 ) Organopolysiloxane represented by the formula:

[0069] The following organic compounds were used as component (B): (b1): Nonylphenoxy octaethylene glycol acrylate having a viscosity of 150 mPa·s (b2): Tridecaethylene glycol diacrylate having a viscosity of 100 mPa·s

[0070] The following compounds were used as component (C): (c1): 1,4-bis(3-thiobutyryloxy)butane (c2): Pentaerythritol tetrakis(3-thiobutyrate)

[0071] The following photoradical initiators were used as component (D): (d1): Diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide

[0072] The following hindered phenol compounds were used as component (E): (e1): 2,6-di-tert-butyl-p-cresol

[0073] The following radical scavengers were used as component (F): (f1): Aluminum-N-nitroso-N-phenylhydroxylamine

[0074] The following organopolysiloxane was used as component (G): (g1) Average unit formula: (Me2ViSiO 1 / 2 ) 0.18 (MeEpSiO 2 / 2 ) 0.28 (PhSiO 3 / 2 ) 0.54 Organopolysiloxane represented by the formula:

[0075] The following organic compounds were used as components (H): (h1): Tinuvin 384-2, a liquid UV absorber in the hydroxyphenylbenzotriazole class manufactured by BASF [Table 1] [Table 2] [Table 3] [Industrial Applicability]

[0076] The composition is easily cured by irradiation with high-energy rays such as ultraviolet light and visible light, provides a transparent cured product, and inhibits cracking and peeling of the cured product in optical devices or image displays. Therefore, the composition is useful as a variety of potting agents, sealants, and adhesives.

Claims

1. (A) 100 parts by mass of an organopolysiloxane having at least one aryl group having 6 to 12 carbon atoms and at least one alkenyl group having 2 to 12 carbon atoms in the molecule; (B) 1 to 50 parts by mass of an organic compound having at least two ether bonds and at least one aliphatic carbon-carbon double bond in the molecule; (C) a thiol group-containing organic compound, (C １ ) an organic compound having two thiol groups in the molecule, and (C ２ ) An organic compound having at least three thiol groups in the molecule 4 to 9.7 parts by mass of a thiol group-containing organic compound comprising (D) 0.05 to 2 parts by mass of a photoradical initiator; Including, A photocurable silicone composition, in which the molar ratio of component (C 1 ) to component (C 2 ) in component (C) is in the range of 0.45 to 2.

8.

2. Component (A) has the average formula: R １ ａ R ２ ｂ SiO （４－ａ－ｂ）／２ (In the formula, R １ is an alkenyl group having 2 to 12 carbon atoms, R ２ is an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an aralkyl group having 7 to 12 carbon atoms, ２ at least 30 mol % of the aryl group or the aralkyl group, and "a" and "b" are positive numbers satisfying 1≦a+b≦2.5 and 0.001≦a / (a+b)≦0.

2.

2. The photocurable silicone composition of claim 1, which is an organopolysiloxane represented by the formula:

3. 2. The photocurable silicone composition according to claim 1, wherein component (B) is an organic compound that has at least two ether bonds and at least one acryloyl group or methacryloyl group in the molecule.

4. 2. The photocurable silicone composition according to claim 1, wherein component (D) is a photoradical initiator having a phosphorus atom.

5. 2. The photocurable silicone composition of claim 1, further comprising (E) a hindered phenol compound in an amount of 0.001 to 1 part by weight per 100 parts by weight of component (A).

6. 2. The photocurable silicone composition according to claim 1, further comprising (F) a radical scavenger other than component (E) in an amount of 0.0001 to 1 part by weight per 100 parts by weight of component (A).

7. 2. The photocurable silicone composition of claim 1, further comprising (G) an adhesion promoter in an amount of 10 parts by weight or less per 100 parts by weight of component (A).

8. A cured product obtained by irradiating the photocurable silicone composition according to any one of claims 1 to 7 with light.

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