Ultraviolet-curable silicone composition, silicone cured product, and optical device

Abstract

The present invention is an ultraviolet-curable silicone composition containing the following components (A)-(D). (A) an organopolysiloxane resin having, as constituent units, a unit represented by formula (1) below, an R1 3SiO1 / 2 unit, an R1 2SiO2 / 2 unit, and an SiO4 / 2unit, wherein 5% or more of the total number of monovalent organic groups bonded to silicon atoms are aryl groups; (B) an organic silicon compound having two or more hydrogen atoms bonded to the silicon atoms in one molecule and having an acryloyloxyalkyl group, a methacryloyloxyalkyl group, an acryloyloxyalkyloxy group, or a methacryloyloxyalkyloxy group bonded to a silicon atom; (C) a photoactive platinum complex catalyst; and (D) a photopolymerization initiator. As a result, the present invention provides an ultraviolet-curable silicone composition that can be cured by ultraviolet irradiation without requiring a heating step in the atmosphere, and that provides a cured product having good adhesive strength.

Description

UV-curable silicone compositions, cured silicone products, and optical devices

[0001] This invention relates to an ultraviolet-curable silicone composition, a cured silicone product, and an optical device.

[0002] In recent years, UV-curable materials have attracted attention as materials that can be cured quickly and with low energy consumption. Photoradical-curable materials, in which radical species are generated by ultraviolet light and polymerization reactions proceed, can be cured in a very short time. However, in the atmosphere, they are inhibited by oxygen, resulting in the formation of uncured areas. To counteract oxygen inhibition, extra steps such as nitrogen replacement or air blockage with a film are required during curing (Patent Document 1). A method using a platinum addition reaction in combination has also been proposed to counter oxygen inhibition on the surface, but this required a heating step after UV irradiation for quick curing (Patent Document 2).

[0003] Japanese Patent Publication No. 2021-195439 Japanese Patent Publication No. 2013-203794

[0004] Conventional technology has the problem that it requires a heating step after UV irradiation in order to cure photoradical-curable materials in a short time.

[0005] The present invention has been made to solve the above problems, and aims to provide an ultraviolet-curable silicone composition that can be cured by ultraviolet irradiation without requiring a heating process in the atmosphere, and that provides a cured product with good adhesive strength.

[0006] To solve the above problems, the present invention provides an ultraviolet-curable silicone composition characterized by containing the following components (A) to (D): (A) A unit represented by the following general formula (1), R １ ３ SiO １／２ Unit, R １ ２ SiO ２／２ Units and SiO ４／２ Organopolysiloxane resins having a unit as a constituent unit, in which 5% or more of the total number of monovalent organic groups bonded to silicon atoms are aryl groups. (In the formula, R １is each independently a monovalent hydrocarbon group having 1 to 20 carbon atoms, and R ２ is an oxygen atom or a divalent hydrocarbon group having 1 to 20 carbon atoms, and R ３ is each independently an acryloyloxyalkyl group, a methacryloyloxyalkyl group, an acryloyloxyalkyloxy group, or a methacryloyloxyalkyloxy group, p is an integer of 0 to 10, and a is an integer of 1 to 3. (B) An organosilicon compound having two or more hydrogen atoms bonded to a silicon atom and having an acryloyloxyalkyl group, a methacryloyloxyalkyl group, an acryloyloxyalkyloxy group, or a methacryloyloxyalkyloxy group bonded to the silicon atom (C) A photoactive platinum complex catalyst (D) A photopolymerization initiator

[0007] For the ultraviolet curable silicone composition of the present invention, it can be cured by ultraviolet irradiation without requiring a heating step under the atmosphere, and can give a cured product having good adhesive strength.

[0008] Further, the R １ of the component (A) is preferably a methyl group, a phenyl group or a vinyl group.

[0009] For the ultraviolet curable silicone composition using such a component (A), it is more excellent in curability, mechanical properties and heat resistance of the cured product.

[0010] Further, as the component (B), HR ４ ２ SiO １／２ unit, HR ４ SiO ２／２ unit and R ３ R ４ SiO ２／２ unit (wherein R ３ represents the same meaning as described above, R ４ are each independently an alkyl group or an aryl group, and one or more of R ４ are aryl groups.) is preferably one containing an organohydrogenpolysiloxane having as a constitutional unit.

[0011] If component (B) contains such an organohydrogenpolysiloxane, a cured product with superior curability and mechanical properties can be obtained.

[0012] Furthermore, the above UV-curable silicone composition may further contain, as component (E), a linear organopolysiloxane represented by the following average composition formula (2). [R ５ R ６ ２ SiO １／２ ] ２ [R ８ ２ SiO ２／２ ] ｂ [R ７ R ９ SiO ２／２ ] ｃ (2) (wherein, R ５ R is an alkenyl group, ６ and R ７ Each of these is independently a monovalent hydrocarbon group having 1 to 20 carbon atoms, and R ８ R is an aryl group, ９ b is an alkyl group, b is an integer from 0 to 50, and c is an integer from 0 to 100. However, when b is 0, R ７ (where c is an aryl group, and c is an integer between 1 and 100.)

[0013] A UV-curable silicone composition containing such component (E) yields a cured product with superior curability and mechanical properties.

[0014] Furthermore, it is preferable that the above UV-curable silicone composition further contains an organopolysiloxane having the average structure shown in the following average composition formula (3) as component (F). [R ３ SiO ３／２ ] ｄ [R １ SiO ３／２ ] ｅ [R １０ O １／２ ] ｆ (3) (wherein, R １ and R ３ This has the same meaning as above, R １０(where is a hydrogen atom or an alkyl group, d is a number satisfying 1 ≤ d ≤ 30, e is a number satisfying 0 ≤ e ≤ 30, and f is a number satisfying 1 ≤ f ≤ 20.)

[0015] A UV-curable silicone composition containing such a (F) component will have superior adhesive strength.

[0016] Furthermore, the present invention provides a cured silicone product which is a cured product of the above-mentioned ultraviolet-curable silicone composition.

[0017] Such a cured material will have good adhesive strength.

[0018] Furthermore, the present invention provides an optical device comprising the above-mentioned silicone cured product.

[0019] Such optical devices offer excellent adhesive strength for the cured silicone material, resulting in high reliability.

[0020] As described above, the UV-curable silicone composition of the present invention can be cured by UV irradiation without requiring a heating process in the atmosphere, and also has excellent adhesive properties, making it useful as an adhesive material or protective material for optical devices and the like.

[0021] As described above, there was a need for the development of an ultraviolet-curable silicone composition that exhibits excellent curability in atmospheric conditions and provides a cured product with superior adhesive strength.

[0022] As a result of diligent research into the above-mentioned problems, the inventors of the present invention have found that the above objectives can be achieved with an ultraviolet-curable silicone composition containing components (A) to (D) described later, and have completed the present invention.

[0023] In other words, the present invention is an ultraviolet-curable silicone composition characterized by comprising the following components (A) to (D): (A) A unit represented by the following general formula (1), R １ ３ SiO １／２ Unit, R １ ２ SiO ２／２ Units and SiO ４／２Organopolysiloxane resins having a unit as a constituent unit, in which 5% or more of the total number of monovalent organic groups bonded to silicon atoms are aryl groups. (In the formula, R １ Each of these is independently a monovalent hydrocarbon group having 1 to 20 carbon atoms, and R ２ R is an oxygen atom or a divalent hydrocarbon group having 1 to 20 carbon atoms. ３ (A) Each is independently an acryloyloxyalkyl group, a methacryloyloxyalkyl group, an acryloyloxyalkyloxy group, or a methacryloyloxyalkyloxy group, where p is an integer from 0 to 10 and a is an integer from 1 to 3. (B) An organosilicon compound having two or more hydrogen atoms bonded to a silicon atom in one molecule, and having an acryloyloxyalkyl group, a methacryloyloxyalkyl group, or a methacryloyloxyalkyloxy group bonded to a silicon atom. (C) A photoactive platinum complex catalyst. (D) A photopolymerization initiator.

[0024] The present invention will be described in detail below, but the present invention is not limited to these descriptions.

[0025] [UV-curable silicone composition] The UV-curable silicone composition of the present invention contains components (A) to (D) described below, but may also contain components (E), (F), (G) and other components as needed. Each component will be described in detail below.

[0026] <Component (A)> Component (A) is the unit shown in the general formula (1) below, R １ ３ SiO １／２ Unit, R １ ２ SiO ２／２ Units and SiO ４／２ This organopolysiloxane resin has a constituent unit, and more than 5% of the total number of monovalent organic groups bonded to silicon atoms are aryl groups. (In the formula, R １ Each of these is independently a monovalent hydrocarbon group having 1 to 20 carbon atoms, and R ２ R is an oxygen atom or a divalent hydrocarbon group having 1 to 20 carbon atoms. ３Each of these is independently an acryloyloxyalkyl group, a methacryloyloxyalkyl group, an acryloyloxyalkyloxy group, or a methacryloyloxyalkyloxy group, where p is an integer from 0 to 10, and a is an integer from 1 to 3.

[0027] R １ Examples of monovalent hydrocarbon groups having 1 to 20 carbon atoms include alkyl groups such as methyl, ethyl, propyl, and butyl groups; cycloalkyl groups such as cyclohexyl and cyclopentyl groups; aryl groups such as phenyl, tolyl, and xylyl groups; aralkyl groups such as benzyl and phenylethyl groups; alkenyl groups such as vinyl, allyl, propenyl, isopropenyl, butenyl, hexenyl, cyclohexenyl, and octenyl groups; and halogenated hydrocarbon groups such as chloromethyl, chloropropyl, and chlorocyclohexyl groups. Preferably, the group is an alkyl group or an aryl group, and more preferably, a methyl, phenyl, or vinyl group.

[0028] R ２ Examples of divalent hydrocarbon groups include linear, branched, or cyclic alkylene groups having 1 to 12 carbon atoms, such as methylene, ethylene, propylene, trimethylene, pentamethylene, hexamethylene, heptamethylene, octamethylene, nonamethylene, and decamethylene; arylene groups having 6 to 12 carbon atoms, such as phenylene, biphenylene, and naphthylene; and aralkylene groups having 7 to 12 carbon atoms, such as phenylenemethylene and methylenephenylmethylene.

[0029] Among these, alkylene groups having 1 to 5 carbon atoms are preferred, and ethylene groups or trimethylene groups are more preferred.

[0030] R ３ The number of carbon atoms in the alkyl (alkylene) group in the acryloyloxyalkyl group, methacryloyloxyalkyl group, acryloyloxyalkyloxy group, or methacryloyloxyalkyloxy group is not particularly limited, but is preferably 1 to 20, more preferably 1 to 10, and particularly preferably 2 or 3.

[0031] (A) Of the total number of monovalent organic groups bonded to silicon atoms in component (A), 5% or more are aryl groups, preferably 10% or more. If the aryl group content is less than 5%, the resulting cured product will have a low refractive index. Phenyl groups are preferred as aryl groups. There is no particular upper limit to the proportion of aryl groups among the total number of monovalent organic groups bonded to silicon atoms in component (A), but it can be, for example, 80%.

[0032] The content of the unit shown in formula (1) above is preferably 5 to 30 mol% relative to the total siloxane units in component (A). Within this range, the mechanical properties of the cured product are good.

[0033] (A) Component is R １ SiO ３／２ Unit (R １ The above has the same meaning. It may also contain trifunctional siloxane units (i.e., organosylsesquioxane units) represented as components, in which case R １ SiO ３／２ Units and SiO ４／２ The total content of the units is preferably 10 to 90 mol%, more preferably 20 to 70 mol%, of the total siloxane units in the organopolysiloxane resin of component (A).

[0034] (A) The number-average molecular weight of component is preferably 500 to 30,000, and more preferably 1,000 to 20,000. Within this range, the workability of the composition is good. Note that the number-average molecular weight is the value on a standard polystyrene basis in gel permeation chromatography (GPC).

[0035] (A) Component (A) may be used alone or in combination of two or more components.

[0036] <Component (B)> Component (B) is an organosilicon compound having two or more hydrogen atoms (i.e., SiH groups) bonded to a silicon atom in one molecule, and having an acryloyloxyalkyl group, methacryloyloxyalkyl group, acryloyloxyalkyl group, or methacryloyloxyalkyl group bonded to a silicon atom.

[0037] The SiH groups in this organosilicon compound act as crosslinking agents, crosslinking them with the alkenyl groups contained in component (A) and component (E), described later, through a hydrosilylation reaction. Component (B) can be organohydrogensilanes, organohydrogenpolysiloxanes, etc., but organohydrogenpolysiloxanes are preferred. There are no particular restrictions on the molecular structure of the organohydrogenpolysiloxane; for example, linear, cyclic, or branched structures can be used.

[0038] Other organic groups bonded to silicon preferably do not contain alkenyl groups, and examples include unsubstituted monovalent hydrocarbon groups, or monovalent hydrocarbon groups substituted with halogen atoms (e.g., chlorine atoms, bromine atoms), epoxy group-containing groups (e.g., epoxy groups, glycidyl groups, glycidyloxy groups), alkoxy groups (e.g., methoxy groups, ethoxy groups, propoxy groups, butoxy groups), etc. Examples of such substituted or unsubstituted monovalent hydrocarbon groups include C1-C6 alkyl groups, C6-C10 aryl groups, and more preferably methyl or phenyl groups. Furthermore, when the monovalent hydrocarbon group has an epoxy group-containing group and / or an alkoxy group as a substituent, the adhesion of the cured product of the silicone composition of the present invention can be improved.

[0039] Component (B) has at least two hydrogen atoms (SiH groups) bonded to silicon atoms in one molecule, preferably 2 to 200, more preferably 3 to 100. If the organosilicon compound of component (B) has a linear or branched structure, these SiH groups may be located only at either the molecular chain terminus or the molecular chain non-terminus, or at both.

[0040] The number of silicon atoms in one molecule of the organosilicon compound of component (B) (degree of polymerization) is preferably 2 to 1,000, more preferably 3 to 200, and even more preferably 4 to 100. Furthermore, the organosilicon compound of component (B) is preferably liquid at 25°C, and the viscosity at 25°C measured by a rotational viscometer is preferably 1 to 1,000 mPa·s, more preferably 10 to 100 mPa·s.

[0041] As the component (B), HR ４ ２ SiO １／２ unit, HR ４ SiO ２／２ unit and R ３ R ４ SiO ２／２ unit (wherein R ３ represents the same meaning as described above, and R ４ are each independently an alkyl group or an aryl group, and one or more of R ４ are aryl groups.). A linear organohydrogenpolysiloxane having as a structural unit, or HR ４ ２ SiO １／２ unit and R ３ SiO ３／２ It is preferably a branched organohydrogenpolysiloxane having a unit structure unit.

[0042] The alkyl group or aryl group of R ４ is exemplified by the same groups as those exemplified for R １ above, and a methyl group or a phenyl group is preferred.

[0043] Also, from the viewpoints of compatibility with the component (A) and the refractive index of the cured product, one or more of R ４ are preferably aryl groups, and more preferably two or more are aryl groups. The aryl group is preferably a phenyl group.

[0044] Further, the organohydrogensiloxane may contain R ４ ３ SiO １／２ unit (M unit), R ４ ２ SiO ２／２ unit (D unit), R ４ SiO ３／２ unit (T unit), or SiO ４／２ unit (Q unit).

[0045] Examples of the component (B) include, but are not limited to, those represented by the following formula. In the formula, Me is a methyl group and Ph is a phenyl group (the same applies hereinafter).

[0046] The amount of component (B) added is preferably such that there are 0.5 to 5.0 hydrogen atoms bonded to silicon atoms in component (B) for each alkenyl group bonded to silicon atoms in component (A) and component (E) described later, and more preferably 0.7 to 3.0 hydrogen atoms bonded to silicon atoms in component (B). Within this range, crosslinking proceeds sufficiently, and a cured product with excellent hardness can be obtained.

[0047] (B) Component may be used alone or in combination of two or more types.

[0048] <Component (C)> Component (C) is a photoactive platinum complex catalyst. That is, it is inert under light shielding and, preferably, when irradiated with light of a wavelength of 200 to 500 nm, it transforms into an active platinum group metal catalyst at room temperature, and is a catalyst for promoting the hydrosilylation reaction between the alkenyl groups in component (A) and component (E) described later and the hydrogen atoms bonded to the silicon atoms in component (B).

[0049] A concrete example of such a (C) component is (η ５ Examples include trialiphatic platinum compounds (-cyclopentadienyl) and their derivatives. Particularly preferred among these are cyclopentadienyltrimethylplatinum, methylcyclopentadienyltrimethylplatinum, and derivatives thereof modified with the cyclopentadienyl group. Bis(β-diketonato)platinum compounds are also listed as suitable examples of component (C), and particularly preferred among these are bis(acetylacetonato)platinum compounds and derivatives thereof modified with the acetylacetonato group. Particularly preferred among these is the trimethyl(methylcyclopentadienyl)platinum complex, from the viewpoint of compatibility with components (A), (B), and (E).

[0050] (C) Component may be used alone or in combination of two or more types.

[0051] The amount of component (C) is not limited as long as it promotes the curing (hydrosilylation reaction) of the composition. Preferably, the amount is such that the platinum group metal atoms in component (C) are in the range of 0.01 to 1000 ppm by mass, relative to the total mass of components (A), (B), and (E) of the composition, and more preferably in the range of 0.05 to 800 ppm. Within this range, the hydrosilylation reaction can be promoted more effectively, and the thickening of the silicone composition during storage can be effectively suppressed.

[0052] <Component (D)> Component (D) is a photopolymerization initiator. That is, it is a photopolymerization initiator that is inert under light shielding and, preferably, generates radical species when irradiated with light of a wavelength of 200 to 500 nm, thereby promoting the radical polymerization of polymerizable functional groups.

[0053] Specific examples of photopolymerization initiators usable in the present invention include 2,2-diethoxyacetophenone, 2,2-dimethoxy-1,2-diphenylethane-1-one (Omnirad 651), 1-hydroxycyclohexylphenyl-ketone (Omnirad 184), 2-hydroxy-2-methyl-1-phenyl-propan-1-one (Omnirad 1173), 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]-phenyl}-2-methyl-propan-1-one (Omnirad 127), phenylglyoxylic acid methyl ester (Omnirad MBF), and 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one (Omnirad Examples include 907), 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butan-1-one (Omnirad 369), 2-dimethylamino-2-(4-methyl-benzyl)-1-(4-morpholin-4-yl-phenyl)butan-1-one (Omnirad 379EG), bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (Omnirad 819), 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (Omnirad TPO), etc. (all manufactured by IGM Resins B.V.).

[0054] (D) As for component (D), from the viewpoint of reducing oxygen inhibition during UV curing and improving surface hardness, an α-aminoacetophenone type photopolymerization initiator is preferred, such as 2,2-diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one (Omnirad 1173), bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (Omnirad 819), 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (Omnirad TPO), 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butan-1-one (Omnirad 369), 2-dimethylamino-2-(4-methyl-benzyl)-1-(4-morpholin-4-yl-phenyl)butan-1-one (Omnirad 379EG) (all of the above are IGM) Resins B.V. is preferred.

[0055] Component (D) may be used alone or in combination of two or more.

[0056] The amount of component (D) added is preferably 0.01 to 20 parts by mass, and more preferably 0.1 to 10 parts by mass, based on 100 parts by mass of the total of components (A), (B), and (E), from the viewpoint of balancing surface hardening and deep hardening properties.

[0057] <Component (E)> The ultraviolet-curable silicone composition of the present invention may further contain (E) a linear organopolysiloxane represented by the following average composition formula (2) as an optional component in order to adjust the physical properties of the composition such as viscosity and hardness. [R ５ R ６ ２ SiO １／２ ] ２ [R ８ ２ SiO ２／２ ] ｂ [R ７ R ９ SiO ２／２ ] ｃ (2) (wherein, R ５ R is an alkenyl group, ６ and R ７Each of these is independently a monovalent hydrocarbon group having 1 to 20 carbon atoms, and R ８ R is an aryl group, ９ b is an alkyl group, b is an integer from 0 to 50, and c is an integer from 0 to 100. However, when b is 0, R ７ (where c is an aryl group, and c is an integer between 1 and 100.)

[0058] R ５ The alkenyl group is preferably a C2-C10, particularly C2-C6, alkenyl group such as vinyl, allyl, propenyl, isopropenyl, butenyl, hexenyl, cyclohexenyl, or octenyl, with vinyl being more preferred due to its availability and cost.

[0059] R ６ and R ７ Examples of monovalent hydrocarbon groups having 1 to 20 carbon atoms include alkyl groups such as methyl, ethyl, propyl, and butyl groups; cycloalkyl groups such as cyclohexyl and cyclopentyl groups; aryl groups such as phenyl, tolyl, and xylyl groups; aralkyl groups such as benzyl and phenylethyl groups; alkenyl groups such as vinyl, allyl, propenyl, isopropenyl, butenyl, hexenyl, cyclohexenyl, and octenyl groups; and halogenated hydrocarbon groups such as chloromethyl, chloropropyl, and chlorocyclohexyl groups. Preferably, the group is an alkyl group or an aryl group, and more preferably, a methyl or phenyl group.

[0060] R ８ The aryl group is the above R ６ and R ７ Similar groups to those exemplified are shown, with the phenyl group being preferred.

[0061] R ９ The alkyl group is the above R ６ and R ７ Similar groups to those exemplified are shown, with the methyl group being preferred.

[0062] b is an integer between 0 and 50, preferably between 2 and 30. c is an integer between 0 and 100, preferably between 0 and 70, and more preferably between 0 and 30. However, when b is 0, R ７ b is an aryl group, and c is between 1 and 100. If b and c are below the above upper limits, the viscosity of component (E) will be within a range that offers excellent workability. The viscosity of component (E) at 25°C is preferably between 50 and 500,000 mPa·s, and more preferably between 500 and 10,000 mPa·s. Within this range, workability is excellent. The viscosity is a value measured using a B-type rotational viscometer in accordance with JIS-K7117-1:1999.

[0063] (E) Specific examples of component include, but are not limited to, the following: [(CH ２ =CH)(CH ３ ) (C ６ H ５ ) SiO １／２ ] ２ [(C ６ H ５ ) ２ SiO ２／２ ] ３ [(CH ２ =CH)(CH ３ ) (C ６ H ５ ) SiO １／２ ] ２ [(C ６ H ５ ) ２ SiO ２／２ ] ２ [(CH ３ ) (C ６ H ５ ) SiO ２／２ ] ２ [(CH ２ =CH)(CH ３ ) ２ SiO １／２ ] ２ [(C ６ H ５ ) ２ SiO ２／２ ] ２ [(CH ３ ) (C ６ H ５ ) SiO２／２ ] ２ [(CH ２ =CH)(CH ３ ) ２ SiO １／２ ] ２ [(C ６ H ５ ) ２ SiO ２／２ ] ９ [(CH ３ ) ２ SiO ２／２ ] １９ [(CH ２ =CH)(CH ３ ) ２ SiO １／２ ] ２ [(C ６ H ５ ) ２ SiO ２／２ ] ３０ [(CH ３ ) ２ SiO ２／２ ] ７０

[0064] (E) Component may be used alone or in combination of two or more types.

[0065] When component (E) is used, the amount added is preferably 10 to 90% by mass, more preferably 30 to 70% by mass, and even more preferably 40 to 60% by mass, relative to the total mass of components (A) and (B), from the viewpoint of the handling properties of the composition and the hardness of the cured product.

[0066] <Component (F)> The ultraviolet-curable silicone composition of the present invention may contain (F) an adhesion aid to improve its adhesion. Examples of this adhesion aid include silane coupling agents and their hydrolysis condensates. Examples of silane coupling agents include epoxy group-containing silane coupling agents, (meth)acrylic group-containing silane coupling agents, isocyanate group-containing silane coupling agents, isocyanurate group-containing silane coupling agents, amino group-containing silane coupling agents, and mercapto group-containing silane coupling agents, and these can be used individually or in combination of two or more.

[0067] The hydrolysis condensate preferably contains an organopolysiloxane having the average structure shown in the following average composition formula (3) as component (F). [R ３ SiO ３／２ ] ｄ [R １ SiO ３／２ ] ｅ [R １０ O １／２ ] ｆ (3) (wherein, R １ and R ３ This has the same meaning as above, R １０ (where is a hydrogen atom or an alkyl group, d is a number satisfying 1 ≤ d ≤ 30, e is a number satisfying 0 ≤ e ≤ 30, and f is a number satisfying 1 ≤ f ≤ 20.)

[0068] R １０ Examples of alkyl groups include methyl, ethyl, propyl, and butyl groups, with methyl or ethyl groups being preferred.

[0069] The adhesive aid may have the adhesive functional group described above, and may also contain an alkenyl group or hydrogen atom bonded to a silicon atom. In this case, it undergoes a hydrosilylation reaction with component (A), component (B), or component (E) and is incorporated into the reaction system.

[0070] Furthermore, adhesive aids that do not contain an organosiloxane skeleton can also be used. Specific examples include allyl glycidyl ether, vinylcyclohexene monooxide, diethyl 2-allyl malonate, allyl benzoate, diallyl phthalate, tetraallyl pyromellitic acid, and triallyl isocyanurate.

[0071] (F) Component may be used alone or in combination of two or more types.

[0072] When using component (F), the amount to be blended is preferably 0.05 to 20 parts by mass, more preferably 0.05 to 10 parts by mass, based on 100 parts by mass of the total of components (A), (B), and (E).

[0073] <Component (G)> The UV-curable silicone composition of the present invention may optionally contain a reaction control agent (G) to control the reactivity of the platinum metal catalyst (C) component, in order to prevent thickening or gelation during composition preparation or before curing.

[0074] Specific examples of reaction control agents include 3-methyl-1-butyne-3-ol, 3-methyl-1-pentin-3-ol, 3,5-dimethyl-1-hexyne-3-ol, 1-ethynylcyclohexanol, ethinylmethyldecylcarbinol, 3-methyl-3-trimethylsiloxy-1-butyne, 3-methyl-3-trimethylsiloxy-1-pentyne, 3,5-dimethyl-3-trimethylsiloxy-1-hexyne, 1-ethynyl-1-trimethylsiloxycyclohexane, dimethylbis(1,1-dimethyl-2-propynyloxy)silane, 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane, 1,1,3,3-tetramethyl-1,3-divinyldisiloxane, etc. These may be used individually or in combination of two or more.

[0075] Among these, 1-ethynylcyclohexanol, ethinylmethyldecylcarbinol, 3-methyl-1-buty-3-ol, and dimethylbis(1,1-dimethyl-2-propynyloxy)silane are preferred.

[0076] When using component (G), the amount added is preferably 0.01 to 2.0 parts by mass, and more preferably 0.01 to 0.1 parts by mass, per 100 parts by mass of the total of components (A), (B), and (E). Within this range, the effect of reaction control is sufficiently exhibited.

[0077] <Other Components> The UV-curable silicone composition of the present invention contains components (A) to (D) above, but may also contain other components other than components (E), (F), and (G) as needed, depending on the purpose of the present invention. Specific examples of other components include antioxidants, light stabilizers, inorganic fillers, etc.

[0078] The UV-curable silicone composition of the present invention may contain an antioxidant to prevent discoloration. Examples of such antioxidants include 2,6-di-t-butyl-4-methylphenol, 2,5-di-t-amylhydroquinone, 2,5-di-t-butylhydroquinone, 4,4'-butylidenebis(3-methyl-6-t-butylphenol), 2,2'-methylenebis(4-methyl-6-t-butylphenol), 2,2'-methylenebis(4-ethyl-6-t-butylphenol), and bis(1,2,2,6,6-pentamethyl-4-piperidine) sebacate, which can be used individually or in combination of two or more.

[0079] When an antioxidant is used, its amount is preferably 1 to 10,000 ppm, more preferably 10 to 1,000 ppm, relative to the total mass of components (A), (B), and (E). By using an amount within this range, the antioxidant capacity is fully exhibited, and a cured product with excellent optical properties is obtained without discoloration, clouding, oxidative degradation, etc.

[0080] The UV-curable silicone composition of the present invention may contain a light stabilizer to provide resistance to photodegradation. Suitable light stabilizers include hindered amine-based stabilizers that capture radicals generated by photooxidative degradation, and the antioxidant effect is further improved when used in combination with an antioxidant. Specific examples of light stabilizers include bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate and 4-benzoyl-2,2,6,6-tetramethylpiperidine.

[0081] When a light stabilizer is used, its amount is preferably 1 to 10,000 ppm, more preferably 10 to 1,000 ppm, relative to the total mass of components (A), (B), and (E). By using an amount within this range, sufficient resistance to photodegradation is achieved, and a cured product with excellent optical properties can be obtained.

[0082] In order to adjust the viscosity of the composition of the present invention or to improve the hardness of the resulting cured product, inorganic fillers such as fumed silica, fused silica, crystalline silica, titanium oxide, and alumina may be included.

[0083] When using inorganic fillers, the amount blended is preferably 0.1 to 20 parts by mass, and more preferably 1 to 10 parts by mass, based on 100 parts by mass of the total of components (A), (B), and (E). By blending within this range, a cured product with excellent workability and mechanical properties can be obtained.

[0084] The ultraviolet-curable silicone composition of the present invention can be obtained by mixing components (A) to (D) above, and optionally components (E), (F), (G), and other components, in any order and stirring. The apparatus used for stirring and other operations is not particularly limited, but a grinder, a three-roll mill, a ball mill, a planetary mixer, etc., can be used. These apparatuses may also be combined as appropriate.

[0085] [Cured product] Furthermore, the present invention provides a silicone cured product which is a cured product of the ultraviolet-curable silicone composition of the present invention.

[0086] Examples of light sources used for curing the UV-curable silicone composition of the present invention include UV LED lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, metal halide lamps, carbon arc lamps, and xenon lamps. A useful wavelength range is 250 to 500 nm, preferably 300 to 420 nm, and more preferably 340 to 410 nm. Among these, LED lamps with a wavelength of 365 nm or 405 nm are preferred, with those with a wavelength of 365 nm being particularly preferred. The amount of UV irradiation (cumulative light dose) is preferably 1 to 50,000 mJ / cm² for a sheet formed from the composition of the present invention to a thickness of about 2.0 mm. ２ More preferably, 10 to 20,000 mJ / cm² ２ That is, an illuminance of 1000 mW / cm². ２ When using ultraviolet light, curing can be achieved by irradiating with ultraviolet light for approximately 0.001 to 50 seconds. After ultraviolet irradiation, heating is not required, and curing can be achieved by the hydrosilylation reaction under conditions such as 25°C for 1 to 48 hours. However, curing can also be accelerated by heating after ultraviolet irradiation.

[0087] Furthermore, it is preferable that the Shore D hardness of the silicone cured product, in accordance with JIS-K6249:2003, be between 20 and 80.

[0088] [Optical Devices] The cured product of the UV-curable silicone composition of the present invention is useful for various devices, but is particularly useful as an adhesive for optical devices, for example, due to its high adhesive properties. In other words, it is possible to provide an optical device equipped with the cured silicone product of the present invention.

[0089] The present invention will be specifically described below using examples and comparative examples, but the present invention is not limited to these.

[0090] The meaning of the abbreviations for each siloxane unit is as follows: M Ｖｉ : (CH ２ =CH)(CH ３ ) ２ SiO １／２ M Ｖｉφ : (CH ２ =CH)(C ６ H ５ ) (CH ３ ) SiO １／２ M Ｈ : H(CH ３ ) ２ SiO １／２ M φＨ : H(C ６ H ５ ) (CH ３ ) SiO １／２ M ＭＡ : D ２φ : (C ６ H ５ ) ２ SiO ２／２ D: (CH ３ ) ２ SiO ２／２ D Ｈ : H(CH ３ ) SiO ２／２ D Ａ : [CH ２ =CHCOO(CH ２ ) ３ ] (CH ３ ) SiO ２／２ Q: SiO ４／２

[0091] [Examples 1-3 and Comparative Examples 1-3] The following components were mixed in the compositions (parts by mass) shown in Table 1 to prepare silicone compositions (Examples 1-3 and Comparative Examples 1-3).

[0092] (A) Component (A-1): M Ｖｉφ １０ M ＭＡ １０ D ２φ ４０ Q ４０ Organopolysiloxane resins represented by

[0093] (B) Component (B-1): M φＨ ２ D Ａ １ D Ｈ ３ Linear organohydrogenpolysiloxane represented by (B-2): M Ｈ ２ D Ａ １ D Ｈ ３ D ２φ １ Linear organohydrogenpolysiloxane represented by (B-3): M φＨ ２ D Ｈ ３ Linear organohydrogenpolysiloxane represented by

[0094] (C) Component (C-1): Toluene solution of trimethyl(methylcyclopentadienyl) platinum complex (platinum concentration 10.0% by mass)

[0095] (D) Component (D-1): 2-hydroxy-2-methyl-1-phenyl-propan-1-one (manufactured by IGM Resins B.V., Omnirad 1173)

[0096] (E) Component (E-1): M Ｖｉ ２ D ２φ ９ D １９ Linear organopolysiloxane represented by

[0097] (F) Component (F-1): A branched organopolysiloxane having an average structure represented by the following formula.

[0098] (G) Component (G-1): Dimethylbis(1,1-dimethyl-2-propynyloxy)silane

[0099]

[0100] The silicone compositions obtained in Examples 1-3 and Comparative Examples 1-3 were evaluated as follows, and the results are shown in Table 2.

[0101] [Curing] The composition is poured into a polytetrafluoroethylene (Teflon®) frame to a thickness of 2 mm, and then cured at 23°C under air using a UV-LED light source (wavelength 365 nm) manufactured by Quantum Ushikata Co., Ltd. at a rate of 1000 mW / cm². ２ ×10 seconds (10,000mJ / cm ２ The material was irradiated. If the resulting 2 mm thick cured material had no liquid portion and was completely cured, it was marked with a circle (○); if a liquid or gel-like portion remained, it was marked with a cross (×).

[0102] [Hardness] Three layers of the 2 mm thick hardened material obtained above (6 mm thick) were stacked, and the Shore D hardness was measured in accordance with JIS-K6249:2003.

[0103] [Glass Adhesion Strength] The composition was sandwiched between two glass plates (25 mm wide x 70 mm deep x 5 mm thick) with an overlap of 10 mm at the edges, and tested under atmospheric pressure using a UV-LED light source (wavelength 365 nm) manufactured by Quantum Ushikata Co., Ltd. at a rate of 1000 mW / cm². ２ ×10 seconds (10,000mJ / cm ２ The material was irradiated and cured, and a test piece was prepared. Using a tensile testing machine (Autograph, manufactured by Shimadzu Corporation), both ends of the test piece were pulled in opposite directions at a tensile speed of 50 mm / min, and the adhesive strength per unit area (MPa) was determined.

[0104]

[0105] As shown in Table 2, the UV-curable silicone compositions of Examples 1 to 3 cured with UV irradiation alone and exhibited good hardness and glass adhesion.

[0106] On the other hand, in Comparative Example 1, which did not contain a photoactive platinum catalyst, the hydrosilylation reaction did not proceed and surface hardening properties decreased. In Comparative Example 2, which did not contain a photopolymerization initiator, radical polymerization did not proceed and only a gel-like state was formed with UV irradiation alone. Furthermore, in Comparative Example 3, which used an organohydrogenpolysiloxane that did not contain a (meth)acrylic group in component (B), deep hardening properties were insufficient.

[0107] This specification includes the following embodiments: [1]: An ultraviolet-curable silicone composition characterized by comprising the following components (A) to (D): (A) a unit represented by the following general formula (1), R １ ３ SiO １／２ Unit, R １ ２ SiO ２／２ Units and SiO ４／２ Organopolysiloxane resins having a unit as a constituent unit, in which 5% or more of the total number of monovalent organic groups bonded to silicon atoms are aryl groups. (In the formula, R １ Each of these is independently a monovalent hydrocarbon group having 1 to 20 carbon atoms, and R ２ R is an oxygen atom or a divalent hydrocarbon group having 1 to 20 carbon atoms. ３ (A) Each is independently an acryloyloxyalkyl group, a methacryloyloxyalkyl group, an acryloyloxyalkyloxy group, or a methacryloyloxyalkyloxy group, where p is an integer from 0 to 10 and a is an integer from 1 to 3. (B) An organosilicon compound having two or more hydrogen atoms bonded to a silicon atom in one molecule, and having an acryloyloxyalkyl group, a methacryloyloxyalkyl group, or a methacryloyloxyalkyloxy group bonded to a silicon atom (C) A photoactive platinum complex catalyst (D) A photopolymerization initiator [2]: The R of component (A) above １ The ultraviolet-curable silicone composition according to [1], characterized in that the group is a methyl group, a phenyl group, or a vinyl group. [3]: As component (B), HR ４ ２ SiO １／２ Units, HR ４SiO ２／２ Units and R ３ R ４ SiO ２／２ Unit (in the formula, R) ３ This has the same meaning as above, R ４ Each is independently an alkyl group or an aryl group, and R ４ The ultraviolet-curable silicone composition according to [1] or [2], characterized in that it contains an organohydrogenpolysiloxane having one or more of the constituent units () as an aryl group. [4]: ​​The ultraviolet-curable silicone composition according to any one of [1] to [3], characterized in that it further contains a linear organopolysiloxane represented by the following average composition formula (2) as component (E). [R ５ R ６ ２ SiO １／２ ] ２ [R ８ ２ SiO ２／２ ] ｂ [R ７ R ９ SiO ２／２ ] ｃ (2) (wherein, R ５ R is an alkenyl group, ６ and R ７ Each of these is independently a monovalent hydrocarbon group having 1 to 20 carbon atoms, and R ８ R is an aryl group, ９ b is an alkyl group, b is an integer from 0 to 50, and c is an integer from 0 to 100. However, when b is 0, R ７ (wherein c is an aryl group and c is an integer from 1 to 100.) [5]: The ultraviolet-curable silicone composition according to any one of [1] to [4], characterized in that it further comprises an organopolysiloxane having the average structure shown in the following average composition formula (3) as component (F). [R ３ SiO ３／２ ] ｄ [R １ SiO ３／２ ] ｅ [R １０ O １／２ ] ｆ (3) (wherein, R１ and R ３ This has the same meaning as above, R １０ (wherein is a hydrogen atom or an alkyl group, d is a number satisfying 1 ≤ d ≤ 30, e is a number satisfying 0 ≤ e ≤ 30, and f is a number satisfying 1 ≤ f ≤ 20.) [6]: A silicone cured product characterized by being a cured product of an ultraviolet-curable silicone composition described in any one of [1] to [5]. [7]: An optical device characterized by comprising the silicone cured product described in [6].

[0108] It should be noted that the present invention is not limited to the embodiments described above. The embodiments described above are illustrative, and any configuration that is substantially identical to the technical idea described in the claims of the present invention and achieves similar effects is included within the technical scope of the present invention.

Claims

1. An ultraviolet-curable silicone composition, characterized by containing the following components (A) to (D). (A) A unit represented by the following general formula (1), R １ ３ SiO １／２ unit, R １ ２ SiO ２／２ unit and SiO ４／２ unit as constituent units, and an organopolysiloxane resin in which 5% or more of the total number of monovalent organic groups bonded to silicon atoms are aryl groups (In the formula, R １ are each independently a monovalent hydrocarbon group having 1 to 20 carbon atoms, R ２ is an oxygen atom or a divalent hydrocarbon group having 1 to 20 carbon atoms, R ３ are each independently an acryloyloxyalkyl group, a methacryloyloxyalkyl group, an acryloyloxyalkyloxy group, or a methacryloyloxyalkyloxy group, p is an integer of 0 to 10, and a is an integer of 1 to 3.) (B) An organosilicon compound having two or more hydrogen atoms bonded to silicon atoms in one molecule and having an acryloyloxyalkyl group, a methacryloyloxyalkyl group, an acryloyloxyalkyloxy group, or a methacryloyloxyalkyloxy group bonded to silicon atoms (C) A photoactive platinum complex catalyst (D) A photopolymerization initiator 2. The R of component (A) １ The ultraviolet-curable silicone composition according to claim 1, characterized in that the group is a methyl group, a phenyl group, or a vinyl group.

3. As component (B) above, HR ４ ２ SiO １／２ Units, HR ４ SiO ２／２ Units and R ３ R ４ SiO ２／２ Unit (in the formula, R) ３ This has the same meaning as above, R ４ Each is independently an alkyl group or an aryl group, and R ４ The ultraviolet-curable silicone composition according to claim 1, characterized in that it contains an organohydrogenpolysiloxane having one or more of the following as constituent units:

4. The ultraviolet-curable silicone composition according to claim 1, further comprising a linear organopolysiloxane represented by the following average composition formula (2) as component (E). [R ５ R ６ ２ SiO １／２ ] ２ [R ８ ２ SiO ２／２ ] ｂ [R ７ R ９ SiO ２／２ ] ｃ (2) (wherein, R ５ R is an alkenyl group, ６ and R ７ Each of these is independently a monovalent hydrocarbon group having 1 to 20 carbon atoms, and R ８ R is an aryl group, ９ b is an alkyl group, b is an integer from 0 to 50, and c is an integer from 0 to 100. However, when b is 0, R ７ (where c is an aryl group, and c is an integer between 1 and 100.) 5. The ultraviolet-curable silicone composition according to claim 1, further comprising an organopolysiloxane having the average structure shown in the following average composition formula (3) as component (F). [R ３ SiO ３／２ ] ｄ [R １ SiO ３／２ ] ｅ [R １０ O １／２ ] ｆ (3) (wherein, R １ and R ３ This has the same meaning as above, R １０ (where is a hydrogen atom or an alkyl group, d is a number satisfying 1 ≤ d ≤ 30, e is a number satisfying 0 ≤ e ≤ 30, and f is a number satisfying 1 ≤ f ≤ 20.) 6. A cured silicone product characterized by being a cured product of an ultraviolet-curable silicone composition according to any one of claims 1 to 5.

7. An optical device characterized by comprising the silicone cured product described in claim 6.

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