Photocurable silicone resin composition

Abstract

Provided is a photocurable silicone resin composition which is capable of forming a cured product having a wide designable range of complex elastic modulus, high attenuation properties, and excellent shear elongation. The photocurable silicone resin composition according to the present invention contains (A) a mercaptoalkyl group-containing organopolysiloxane, (B) a linear organopolysiloxane containing aliphatic unsaturated groups at least at both ends, and (C) a photopolymerization initiator. Component (A) is composed of an organopolysiloxane (A1) containing mercaptoalkyl groups at both terminals and an organopolysiloxane (A2) containing two or more mercaptoalkyl groups bonded to a silicon atom per molecule, the ratio of the number of mercaptoalkyl groups in component (A) to the number of aliphatic unsaturated groups in component (B) being 0.70 or more and less than 1.00, and the organopolysiloxane (A1) is composed of an organopolysiloxane (A2) containing two or more mercaptoalkyl groups bonded to a silicon atom at both terminals and an organopolysiloxane (A2) containing two or more mercaptoalkyl groups bonded to a silicon atom per molecule. The ratio of the number of mercaptoalkyl groups in component (A1) to the number of aliphatic unsaturated groups in component (B) is 0.06 or more.

Description

Technical Field

[0001] The present invention relates to a photocurable silicone resin composition, and more particularly to a photocurable silicone resin composition capable of forming a cured product (silicone gel) having a wide designable elastic modulus, high attenuation, and excellent shear elongation. Background Art

[0002] Silicone gels are used as sealing materials for electrical and electronic parts, coating materials for sensors, potting materials, and damping materials due to their excellent heat resistance, electrical insulation, and flexibility. Among them, photocurable silicone resin compositions having a photopolymerizable functional group and a thiol-ene reaction system that forms silicone gel by light curing with ultraviolet light or the like are mainly used in electronic devices, along with recent production automation.

[0003] Moreover, in recent years, with the diversification of uses, the demand for photocurable silicone resin compositions that can form cured products (silicone gels) that have excellent elongation in addition to basic physical properties such as hardness, attenuation performance, and viscosity has increased in the use of sealing materials, coating materials, potting materials, vibration-proof materials, vibration-damping materials, optical adhesives (OCR, OCA), etc. The reason is that when the attenuation performance of silicone gel is improved, its flexibility tends to increase. Therefore, when impact or vibration is applied, silicone gel is easily deformed. At this time, if the elongation is lacking, the silicone gel is easily damaged. Therefore, in such uses, it is important to have excellent elongation while maintaining high attenuation performance. In particular, when it is envisioned to be used as a vibration-damping material, the shear elongation becomes important, and a material that does not break even when the shear strain (elongation) exceeds 100% is required. The design of the basic physical properties of the silicone gel is generally adjusted by making the photocurable silicone resin composition contain solid fillers such as silica or resin, but this method is difficult to take into account both attenuation performance and elongation, which becomes a problem. Therefore, in order to improve the elongation of a photocurable silicone resin composition, Patent Document 1 proposes a UV-curable silicone resin composition, which comprises a specific straight-chain organopolysiloxane (B) containing an aliphatic unsaturated group, an organopolysiloxane (A2) containing more than two mercaptoalkyl groups bonded to silicon atoms, and a specific organopolysiloxane (A1) containing dithiols at both ends, wherein the ratio of the number of thiol groups in the component (A1+A2) to the number of aliphatic unsaturated groups in the component (B) is 1 to 3.

[0004]

Prior art documents

[0005] [Patent Literature]

[0006] [Patent Document 1] Japanese Patent No. 6426023 Summary of the invention

[0007] [Problems to be solved by the invention]

[0008] However, in the photocurable silicone resin composition of Patent Document 1, although the elongation of the cured product is improved, there are problems such as too high complex elastic modulus or poor attenuation. In addition, in order to adjust the viscosity in the uncured state in the use of coating materials, potting materials, damping materials, etc., when the photocurable silicone resin composition contains solid fillers such as silica or resin, the complex elastic modulus of the cured product is further improved. Therefore, there is also room for improvement in the elastic modulus of the cured product (silicone gel) of the photocurable silicone resin composition in that the designable range is narrowed.

[0009] Therefore, the present invention has been made to solve the above-mentioned problems of the prior art, and an object thereof is to provide a photocurable silicone resin composition capable of forming a cured product having a wide designable range of complex elastic modulus, high attenuation, and excellent shear elongation.

[0010]

Methods to solve the problem

[0011] The photocurable silicone resin composition of the present invention is a photocurable silicone resin composition comprising the following components: an organopolysiloxane (A) containing a mercaptoalkyl group, a linear organopolysiloxane (B) containing an aliphatic unsaturated group at least at both ends, and a photopolymerization initiator (C), wherein the organopolysiloxane (A) is composed of an organopolysiloxane (A1) containing a mercaptoalkyl group at both ends and an organopolysiloxane (A2) containing 2 or more mercaptoalkyl groups bonded to silicon atoms per molecule, the ratio of the number of mercaptoalkyl groups in the organopolysiloxane (A) to the number of aliphatic unsaturated groups in the organopolysiloxane (B) is 0.70 or more and less than 1.00, and the ratio of the number of mercaptoalkyl groups in the organopolysiloxane (A1) to the number of aliphatic unsaturated groups in the organopolysiloxane (B) is 0.06 or more. In the present specification, the organopolysiloxane (A) containing a mercaptoalkyl group is referred to as an organopolysiloxane (A) or a component (A), the organopolysiloxane (A1) containing a mercaptoalkyl group at both ends is referred to as an organopolysiloxane (A1) or a component (A1), the organopolysiloxane (A2) containing two or more mercaptoalkyl groups bonded to a silicon atom per molecule is referred to as an organopolysiloxane (A2) or a component (A2), the straight-chain organopolysiloxane (B) containing an aliphatic unsaturated group at least at both ends is referred to as an organopolysiloxane (B) or a component (B), and the photopolymerization initiator (C) is referred to as a component (C).

[0012] The photocurable silicone resin composition of the present invention is constituted in the following manner: an organopolysiloxane (A1) containing a mercaptoalkyl group at both ends is cross-linked with a linear organopolysiloxane (B) containing an aliphatic unsaturated group at both ends to extend the chain length of the organopolysiloxane (B), and an organopolysiloxane (A2) containing two or more mercaptoalkyl groups bonded to silicon atoms in one molecule is cross-linked with the aliphatic unsaturated groups remaining in the above-mentioned organopolysiloxane molecule with extended chain length, thereby lengthening the siloxane chains between the cross-linking points. At this time, by making the ratio of the number of mercaptoalkyl groups in the organopolysiloxane (A) to the number of aliphatic unsaturated groups in the organopolysiloxane (B) greater than or equal to 0.70 and less than 1.00, and making the ratio of the number of mercaptoalkyl groups in the organopolysiloxane (A1) to the number of aliphatic unsaturated groups in the organopolysiloxane (B) greater than or equal to 0.06, the viscoelastic properties of the cured product (silicone gel) of the photocurable silicone resin composition can be controlled, thereby obtaining a photocurable silicone resin composition having cured product properties with a wide designable range of complex elastic modulus, high attenuation, and excellent shear elongation.

[0013] In addition, in the photocurable silicone resin composition of the present invention, the content of the photopolymerization initiator (C) is preferably 0.05 to 50 parts by mass relative to 100 parts by mass of the organopolysiloxane (B). Thus, a photocurable silicone resin composition having a good effect based on the above-mentioned action can be obtained. In addition, the aliphatic unsaturated group in the organopolysiloxane (B) in the photocurable silicone resin composition of the present invention is preferably a vinyl group. Thus, a photocurable silicone resin composition having a good effect based on the above-mentioned action can be obtained.

[0014] The photocurable silicone resin composition of the present invention preferably further contains a filler (D). This can provide a photocurable silicone resin composition capable of forming a cured product having desired viscoelastic properties and functionality in addition to the above-mentioned effects.

[0015] In addition, in the photocurable silicone resin composition of the present invention, the filler (D) is preferably at least one substance selected from the group consisting of silica, silicone resin, solid resin, fibrous compound and metal oxide. Thus, the preferred constituent components of the photocurable silicone resin composition that can form a cured product having various viscoelastic properties and functionalities are selected.

[0016] [Effects of the Invention]

[0017] The photocurable silicone resin composition of the present invention comprises: an organopolysiloxane (A) composed of an organopolysiloxane (A1) containing a mercaptoalkyl group at both ends and an organopolysiloxane (A2) containing a mercaptoalkyl group bonded to a silicon atom; a linear organopolysiloxane (B) containing an aliphatic unsaturated group at both ends; and a photopolymerization initiator (C); the organopolysiloxane (B) whose chain length is extended by the organopolysiloxane (A1) is crosslinked with the organopolysiloxane (A2) in a manner that By setting the ratio of the number of mercaptoalkyl groups in the organopolysiloxane (A1) to the number of aliphatic unsaturated groups in the organopolysiloxane (B) and the ratio of the number of mercaptoalkyl groups in the organopolysiloxane (A) to the number of aliphatic unsaturated groups in the organopolysiloxane (B) to specific ranges, a photocurable silicone resin composition can be provided that can form a cured product having a wide designable range of complex elastic modulus, high attenuation, and excellent shear elongation. Thus, a sealing material, coating material, potting material, vibration-proof material, vibration-damping material, optical adhesive (OCR, OCA), etc. that does not break even when the shear elongation exceeds 100% and exhibits high attenuation can be provided. DETAILED DESCRIPTION

[0018] The photocurable silicone resin composition of the present invention is a photocurable silicone resin composition comprising an organopolysiloxane (A) containing a mercaptoalkyl group, a linear organopolysiloxane (B) containing an aliphatic unsaturated group at least at both ends, and a photopolymerization initiator (C), wherein the organopolysiloxane (A) is composed of an organopolysiloxane (A1) containing a mercaptoalkyl group at both ends, and an organopolysiloxane (A2) containing 2 or more mercaptoalkyl groups bonded to silicon atoms per molecule, the ratio of the number of mercaptoalkyl groups in the organopolysiloxane (A) to the number of aliphatic unsaturated groups in the organopolysiloxane (B) is 0.70 or more and less than 1.00, and the ratio of the number of mercaptoalkyl groups in the organopolysiloxane (A1) to the number of aliphatic unsaturated groups in the organopolysiloxane (B) is 0.06 or more. The following is a detailed description.

[0019] (Organopolysiloxane (A))

[0020] The mercaptoalkyl group-containing organopolysiloxane (A) constituting the photocurable silicone resin composition of the present invention is composed of an organopolysiloxane (A1) containing mercaptoalkyl groups at both ends and an organopolysiloxane (A2) containing two or more mercaptoalkyl groups bonded to silicon atoms per molecule.

[0021] (Organopolysiloxane (A1))

[0022] The organopolysiloxane (A1) constituting the organopolysiloxane (A) is a straight-chain organopolysiloxane having a mercaptoalkyl group at both ends, and is a component that functions as a chain extender for extending the chain length of the organopolysiloxane (B) by a thiol-ene reaction between the mercaptoalkyl groups at both ends and the aliphatic unsaturated groups of the organopolysiloxane (B). A specific preferred example is an organopolysiloxane represented by the structure of the following formula 1: wherein Ra is independently a C1-C6 alkyl group, a C6-C12 aryl group, or -Si(OX)3 (wherein X is independently a C1-C6 alkyl group), Rb is independently a C1-C6 alkyl group or a C6-C12 aryl group, and Rc is independently a C1-C6 alkylene group. p is an integer greater than or equal to 3, and is preferably a number that makes the viscosity of the organopolysiloxane (A1) at 23°C be 1 to 200 cP. In this specification, the viscosity of the composition or its constituent materials according to the present invention refers to a value measured by a rotational viscometer using a rotor No. 2 to No. 4 at 30 rpm to 60 rpm and 23° C. The organopolysiloxane (A1) is not particularly limited, and for example, model “X-22-167C” (mercapto equivalent: 0.4348 mmol / g) manufactured by Shin-Etsu Chemical Co., Ltd. can be used.

[0023]

Chemical formula 1

[0024]

[0025] In addition, as an example of another embodiment of the photocurable silicone resin composition, when the silicone gel is used for an application that does not require high heat resistance, the organopolysiloxane (A1) may have a structure in which a part of the siloxane chain is replaced with a hydrocarbon chain. In addition, part or all of the amount of the organopolysiloxane (A1) may be replaced by a chain extender composed of a linear hydrocarbon structure having mercapto groups at both ends.

[0026] (Organopolysiloxane (A2))

[0027] The organopolysiloxane (A2) constituting the organopolysiloxane (A) is an organopolysiloxane containing two or more mercaptoalkyl groups bonded to silicon atoms per molecule, and is a crosslinking agent component for crosslinking the organopolysiloxane (B) by reacting the mercaptoalkyl groups bonded to silicon atoms with the aliphatic unsaturated groups of the organopolysiloxane (B) by thiol-ene reaction, and curing the photocurable silicone resin composition. The structure of the main chain of the organopolysiloxane (A2) may be any one of a linear, branched, or cyclic structure, and from the viewpoint of three-dimensional crosslinking, an organopolysiloxane in which the side chains of the main chain are substituted with mercaptoalkyl groups is preferred. Specifically, the organopolysiloxane (A2) is not particularly limited, and for example, the model "KF-2001" (mercapto equivalent: 0.5263 mmol / g) of Shin-Etsu Chemical Co., Ltd., the model "SMS-022" (mercapto equivalent: 0.3286 mmol / g) of Gelest Co., Ltd., etc. may be used.

[0028] (Organopolysiloxane (B))

[0029] The organopolysiloxane (B) constituting the photocurable silicone resin composition of the present invention is a linear organopolysiloxane containing an aliphatic unsaturated group at least at both ends, and can be selected, for example, from a linear organopolysiloxane having a structure of the following formula 2, wherein R is an aliphatic unsaturated group, R1 to R4 are unsubstituted or substituted monovalent hydrocarbon groups of the same or different types, and q is an integer greater than or equal to 10, preferably a number that makes the viscosity of the organopolysiloxane (B) at 23° C. 100 cP to 25000 cP. Examples of the aliphatic unsaturated group include vinyl, propenyl, butenyl, hexenyl, etc., and vinyl is preferred in terms of ease of synthesis. Specific examples of R1 to R4 include C1 to C6 alkyl groups (e.g., methyl, ethyl, propyl, etc.) or C6 to C12 aryl groups (e.g., phenyl, tolyl, xylyl, etc.). From the perspective of ease of synthesis, the C1 to C6 alkyl group is preferably a methyl group, and the C6 to C12 aryl group is preferably a phenyl group. The organopolysiloxane (B) is not particularly limited, and for example, the product model "DMS-V33" (vinyl equivalent: 0.0465 mmol / g) of Gelest Company and the product model "DMS-V22" (vinyl equivalent: 0.2222 mmol / g) of Gelest Company can be used.

[0030]

Chemical formula 2

[0031]

[0032] From the viewpoint of obtaining a cured product having a wide range of elastic modulus that can be adjusted in design, high damping properties, and excellent shear elongation, the mixing ratio of the organopolysiloxane (A) and the organopolysiloxane (B) composed of the organopolysiloxane (A1) and the organopolysiloxane (A2) is such that the ratio of the number of mercaptoalkyl groups in the organopolysiloxane (A) to the number of aliphatic unsaturated groups in the organopolysiloxane (B) is greater than or equal to 0.70 and less than 1.00, and the ratio of the number of mercaptoalkyl groups in the organopolysiloxane (A1) to the number of aliphatic unsaturated groups in the organopolysiloxane (B) is greater than or equal to 0.06. When the ratio of the number of mercaptoalkyl groups in the organopolysiloxane (A) to the number of aliphatic unsaturated groups in the organopolysiloxane (B) is less than 0.70, crosslinking by thiol-ene reaction becomes insufficient, and the photocurable silicone resin composition does not cure. When the ratio is greater than or equal to 1.00, the elastic modulus of the cured product becomes too high, or good damping properties cannot be obtained. Therefore, the ratio of the number of mercaptoalkyl groups in the organopolysiloxane (A) to the number of aliphatic unsaturated groups in the organopolysiloxane (B) is preferably greater than or equal to 0.70 and less than 1.00, more preferably greater than or equal to 0.70 and less than or equal to 0.95, and further preferably greater than or equal to 0.70 and less than or equal to 0.90. In addition, when the ratio of the number of mercaptoalkyl groups in the organopolysiloxane (A1) to the number of aliphatic unsaturated groups in the organopolysiloxane (B) is less than 0.06, good shear elongation of the cured product cannot be obtained. Therefore, the ratio of the number of mercaptoalkyl groups in the organopolysiloxane (A1) to the number of aliphatic unsaturated groups in the organopolysiloxane (B) is preferably 0.06 or more, more preferably 0.06 or more and 0.5 or less, and further preferably 0.1 or more and 0.5 or less.

[0033] (Photopolymerization initiator (C))

[0034] The photopolymerization initiator (C) constituting the photocurable silicone resin composition of the present invention is a component that promotes the crosslinking reaction between the mercaptoalkyl group in the organopolysiloxane (A) and the aliphatic unsaturated group in the organopolysiloxane (B) under ultraviolet irradiation, and a known photopolymerization initiator that acts on a thiol-ene reaction can be used. Specifically, 1-hydroxy-cyclohexyl-phenyl-ketone, 2,2-dimethoxy-2-phenylacetophenone, xanthone, fluorenone, benzaldehyde, fluorene, anthraquinone, triphenylamine, carbazole, 3-methylacetophenone, 4-chlorobenzophenone, 4,4'-dimethoxybenzophenone, 4,4'-diaminobenzophenone, Michler's ketone, benzoin propyl ether, benzoin ethyl ether, benzyl dimethyl ketal, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropane-1-one, 2-hydroxy The photopolymerization initiator (C) may be used alone or in combination of two or more. The amount of the photopolymerization initiator (C) may be an effective amount for initiating the thiol-ene reaction by ultraviolet rays, and is preferably 0.05 to 50 parts by mass, more preferably 0.1 to 5 parts by mass, based on 100 parts by mass of the organopolysiloxane (B).

[0035] (Filling agent (D))

[0036] The photocurable silicone resin composition of the present invention may also contain a filler (D) for imparting viscoelastic properties or further functionality to the cured product. As filler (D), there is no particular limitation as long as it is a powdered filler that can impart an adjustment effect and functionality to the viscoelastic properties of the cured product and does not hinder the thiol-ene reaction. For example, fumed silica represented by AEROSIL (registered trademark) of AEROSIL of Japan, REOLOSIL (registered trademark) of TOKUYAMA, WACKER HDK (registered trademark) of Asahi Kasei Wacker Co., Ltd., TOKUSIL (registered trademark) of TOKUYAMA, silica or silicone resin, metal oxides such as alumina, fibrous compounds such as cellulose nanofibers, etc. can be appropriately selected and applied according to the purpose.

[0037] Furthermore, any additives may be added to the photocurable silicone resin composition of the present invention within the range that does not hinder the effects of the present invention. For example, known additives such as pigments or conductivity-imparting agents, flame retardants, dispersants, adhesion / bonding-imparting agents, polymerization inhibitors, antioxidants as additives for improving weather resistance, ultraviolet absorbers, and light stabilizers may be used as needed.

[0038] As the adhesiveness and adhesion imparting agent, for example, one or more silicone resin adhesion improving agents selected from the group consisting of MQ resin, MDQ resin, MT resin, MDT resin, MDTQ resin, DQ resin, DTQ resin and TQ resin (wherein, no aliphatic unsaturated group and mercapto group are contained) are preferred. From the viewpoint of fluidity and dispersibility in the photocurable silicone resin composition, one or more silicone resin adhesion improving agents selected from the group consisting of MQ resin, MDQ resin, MDT resin and MDTQ resin are more preferred. From the viewpoint of adhesion imparting effect and easy structure control, MQ resin is more preferred. In addition, a silane coupling agent may be added for improving adhesion to the object to be bonded. Examples of the silane coupling agent include triethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 1,3-bis(3-methacryloxypropyl)tetramethyldisiloxane, trimethoxysilylpropyldiallyl isocyanurate, bis(trimethoxysilylpropyl)allyl isocyanurate, tris(trimethoxysilylpropyl)isocyanurate, triethoxysilylpropyldiallyl isocyanurate, bis(triethoxysilylpropyl)allyl isocyanurate, and tris(triethoxysilylpropyl)isocyanurate. In addition, as other examples of silane coupling agents, disiloxane compounds having functional groups such as (meth)acryloyloxy, alkoxy (e.g., methoxy, ethoxy, propoxy), and amino groups, such as 1,3-bis(3-methacryloxypropyl)tetramethyldisiloxane, may also be used. Among them, from the perspective of improving adhesion and bonding, it is preferred to contain an aliphatic unsaturated group, and 3-methacryloxypropyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, and 1,3-bis(3-methacryloxypropyl)tetramethyldisiloxane are more preferred. The adhesiveness and bonding agent may be one or more.

[0039] As the antioxidant, an antioxidant that can add the function of preventing oxidation of the cured product of the composition of the present invention and improving weather resistance can be used, for example, hindered amine antioxidants or hindered phenol antioxidants can be listed. As the hindered amine antioxidant, a known substance can be appropriately selected, for example, N,N',N",N-tetrakis-(4,6-bis(butyl-(N-methyl-2,2,6,6-tetramethylpiperidin-4-yl)amino)-triazine-2-yl)-4,7-diazadecane-1,10-diamine, dibutylamine·1,3,5-triazine·N,N'-bis-(2,2,6,6-tetramethyl-4-piperidinyl-1,6-hexamethylenediamine·N-(2,2,6, 6-tetramethyl-4-piperidinyl)butylamine, poly[{6-(1,1,3,3-tetramethylbutyl)amino-1,3,5-triazine-2,4-diyl}{(2,2,6,6-tetramethyl-4-piperidinyl)imino}hexamethylene{(2,2,6,6-tetramethyl-4-piperidinyl)imino}], polymer of dimethyl succinate and 4-hydroxy-2,2,6,6-tetramethyl-1-piperidinylethanol, [bis(2,2,6,6-tetramethyl-1-piperidinyl)butylamine, poly[{6-(1,1,3,3-tetramethylbutyl)amino-1,3,5-triazine-2,4-diyl}{(2,2,6,6-tetramethyl-4-piperidinyl)imino}hexamethylene{(2,2,6,6-tetramethyl-4-piperidinyl)imino}], polymer of dimethyl succinate and 4-hydroxy-2,2,6,6-tetramethyl-1-piperidinylethanol, 1,2,2,6,6-pentamethyl-4-piperidinyl) [3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]malonate, 1,2,2,6,6-pentamethyl-4-piperidinyl sebacate, bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidinyl) [3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]malonate, 1,2,2,6,6-pentamethyl-4-piperidinyl sebacate, bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate, bis(1,2,2,6 ,6-pentamethyl-4-piperidinyl) sebacate, 1-[2-[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxy]ethyl]-4-[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxy]-2,2,6,6-tetramethylpiperidine, 4-benzoyloxy-2,2,6,6-tetramethylpiperidine, 8-acetyl-3-dodecyl-7,7,9,9-tetramethyl-1,3,8-triazaspiro[4.5]decane-2,4-dione, etc.

[0040] On the other hand, as the hindered phenol antioxidant, a known substance can be appropriately selected, and examples thereof 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), N,N'-hexane-1,6-diylbis[3-(3 ,5-di-tert-butyl-4-hydroxyphenylpropionamide), phenylpropionic acid 3,5-bis(1,1-dimethylethyl)-4-hydroxy C7-C9 side chain alkyl ester, 2,4-dimethyl-6-(1-methylpentadecyl)phenol, [[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]phosphonic acid diethyl ester, 3,3',3",5,5',5"-hexane-tert-butyl-4-a,a',a"-(all Trimethylol-2,4,6-methylphenyl) tri-p-cresol, calcium diethyl bis[[[3,5-bis-(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]phosphonate], 4,6-bis(octylthiomethyl)-o-cresol, ethylene bis(oxyethylene) bis[3-(5-tert-butyl-4-hydroxy-m-tolyl) propionate], hexamethylene bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione, a reaction product of N-phenylaniline and 2,4,4-trimethylpentene, 2,6-di-tert-butyl-4-(4,6-bis(octylthio)-1,3,5-triazine-2-ylamino)phenol, etc., but not limited thereto. The above antioxidant may be one or more.

[0041] As a light stabilizer, a material that can add the function of preventing the composition or its cured product from photooxidative degradation according to the present invention can be used, for example, benzotriazoles, hindered amines, benzoate compounds, etc. can be cited. Among them, as a light stabilizer, a hindered amine light stabilizer is preferred. Among them, in order to improve the storage stability of the composition, a hindered amine light stabilizer containing a tertiary amine is preferably used. As a hindered amine light stabilizer containing a tertiary amine, TINUVIN622LD, TINUVIN 144, CHIMASSORC119FL (all of the above are made by BASF), MARKLA-57, LA-62, LA-67, LA-63 (all of the above are made by Asahi Electric Industry Co., Ltd.), SANOL LS-765, LS-292, LS-2626, LS-1114, LS-744 (all of the above are made by Sankyo Co., Ltd.), etc. can be cited. In addition, as the ultraviolet absorber that functions as a light resistance stabilizer, for example, ultraviolet absorbers such as benzotriazoles, triazines, benzophenones, or benzoate compounds can be cited. As the ultraviolet absorber, a known ultraviolet absorber can be appropriately selected, for example, 2,4-di-tert-butyl-6-(5-chlorobenzotriazol-2-yl)phenol, 2-(2H-benzotriazol-2-yl)-4,6-di-tert-amylphenol, 2-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol, 3-(3-(2H-benzotriazol-2-yl)-5-tert-butyl-4-hydroxyphenyl)propionate / polyethylene glycol can be cited. 300 reaction products, benzotriazole type ultraviolet absorbers such as 2-(2H-benzotriazole-2-yl)-6-(linear and side chain dodecyl)-4-methylphenol, triazine type ultraviolet absorbers such as 2-(4,6-diphenyl-1,3,5-triazine-2-yl)-5-[(hexyl)oxy]-phenol, benzophenone type ultraviolet absorbers such as octanone, benzoate type ultraviolet absorbers such as 2,4-di-tert-butylphenyl-3,5-di-tert-butyl-4-hydroxybenzoate, etc. The above-mentioned light stabilizer and ultraviolet absorber may be one kind or two or more kinds.

[0042] (Physical Properties of Photocurable Silicone Resin Composition)

[0043] Among the physical properties of the photocurable silicone resin composition of the present invention, the viscosity of the composition can be appropriately set according to the application. From the viewpoint of coating properties or spraying properties using a dispenser, the viscosity at 23° C. is preferably 50 cP to 10,000 cP, more preferably 70 cP to 9,000 cP, and even more preferably 100 cP to 7,000 cP.

[0044] (Physical Properties of Cured Material of Photocurable Silicone Resin Composition)

[0045] The photocurable silicone resin composition of the present invention has the above-mentioned structure. In a state where the organopolysiloxane (A1) is linked to the organopolysiloxane (B) to extend the chain length of the organopolysiloxane (B), the organopolysiloxane (A2) is cross-linked to extend the siloxane chain between the cross-linking points, thereby contributing to the improvement of the shear elongation of the cured product. Furthermore, by setting the ratio of the number of mercaptoalkyl groups in the organopolysiloxane (A1) to the number of aliphatic unsaturated groups in the organopolysiloxane (B) to be 0.06 or more, and setting the ratio of the number of mercaptoalkyl groups in the organopolysiloxane (A) to the number of aliphatic unsaturated groups in the organopolysiloxane (B) to be 0.70 or more and less than 1.00, the linking reaction of the component (A1) and the component (B) and the cross-linking reaction of the component (B) with an extended chain length and the component (A2) are carried out so as to achieve the desired properties of the cured product. Thus, a silicone gel having cured product characteristics with a wide designable range of complex elastic modulus, high attenuation, and excellent shear elongation can be obtained. Specifically, as the attenuation of the cured product, the viscoelastic characteristic tanδ (10 Hz) is preferably greater than or equal to 0.5, and when used as a damping material for precision instruments, it is more preferably in the range of 0.5 to 2.0. In addition, relative to the shear elongation of a cured product composed of a composition composed of an organic polysiloxane (A2) and an organic polysiloxane (B) without component (A1), and the ratio of the number of mercaptoalkyl groups in the organic polysiloxane (A) to the number of aliphatic unsaturated groups in the organic polysiloxane (B) is equal, the shear elongation of the cured product is preferably greater than or equal to 110%, more preferably greater than or equal to 200%, and further preferably greater than or equal to 300%. In particular, when used as a damping material for precision instruments, tanδ and shear elongation are preferably within the above range.

[0046] (Application of photocurable silicone resin composition)

[0047] The photocurable silicone resin composition of the present invention has the above-mentioned high attenuation and shear elongation properties obtained by photocuring, so it will not break even when the shear elongation exceeds 100%, and can be used as a sealing material, coating material, potting material, vibration-proof material, vibration-damping material, optical adhesive (OCR, OCA) with high attenuation. In addition, it also maintains high attenuation and is difficult to break for vibrations in the high-frequency range of 10 Hz or more in optical devices such as optical pickup modules, and is suitable as a damping component with excellent vibration damping properties.

[0048] The photocurable silicone resin composition of the present invention can be obtained by mixing the above-mentioned (A) to (C) components or (A) to (D) components, as well as fillers or other various components added as needed, in a prescribed mixing ratio. The order of mixing the above-mentioned (A) to (C) components or (A) to (D) components is not particularly limited. In addition, as the (A) component, it is also possible to pre-react part or all of the (A1) component and the (A2) component in the presence of a photopolymerization initiator (C) to achieve chain length extension, and then mix the (B) component or the (D) component. As a mixing method, there is no particular limitation, and known methods such as a manual mixer or a chemical mixer can be used. The photocurable silicone resin composition of the present invention forms a cured product by irradiating active energy rays. As active energy rays, ultraviolet rays, electron beams, X-rays or radiation, etc. can be listed. From the viewpoint of ease of operation, ultraviolet rays are preferably used. The light source of the ultraviolet rays to be irradiated or the wavelength range of the ultraviolet rays are not particularly limited. For example, all known devices such as low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, black light lamps, microwave-excited mercury lamps, metal halide lamps, sodium lamps, halogen lamps, xenon lamps, LEDs, fluorescent lamps, sunlight, electron beam irradiation devices, etc. can be used.

[0049] [Example]

[0050] Hereinafter, the present invention will be described in more detail by way of examples and comparative examples, but the present invention is not limited to these examples.

[0051] [Measurement and evaluation methods]

[0052] For each composition of the examples and comparative examples, the photocurable silicone resin composition was formed into a sheet on a transparent PP film so that the thickness of the cured product was 2 mm, and irradiated with 3000 mJ / cm from each direction of the top and bottom surfaces. 2 The sheet was solidified by ultraviolet light with a wavelength of 365 nm to prepare a measurement sample. The following measurements (1) to (3) were performed using a rheometer (ARES-G2, manufactured by TA Instruments).

[0053] (1) Shear elongation

[0054] At 25°C, 1.0 Hz, and a strain of 100% to 1500%, a Strain Sweep test was performed on each measured sample, and the strain value when tanδ became the minimum value was taken as the shear elongation. The following composition was prepared as the composition involved in each comparative example, wherein the composition only did not contain component (A1), was composed of an organopolysiloxane (A2) and an organopolysiloxane (B), and the ratio of the number of mercaptoalkyl groups (SH) in the organopolysiloxane (A) to the number of aliphatic unsaturated groups (Vi) in the organopolysiloxane (B) (hereinafter referred to as the SH / Vi ratio) was equal; the ratio of the shear elongation value of the measured sample of each embodiment to the shear elongation value of the measured sample of each comparative example was calculated as the elongation improvement rate (%). An elongation improvement rate of 110% or more was judged as qualified (○), and less than 110% was judged as unqualified (×). Furthermore, when determining the elongation improvement rate, the comparative examples corresponding to the following examples, which do not contain only the organopolysiloxane (A1) and have the same SH / Vi ratio, are as follows: Examples 1, 4, and Comparative Example 7 are Comparative Example 1, Example 2 is Comparative Example 2, Example 3 is Comparative Example 3, Example 5 is Comparative Example 4, Examples 6, 9, and Comparative Example 14 are Comparative Example 8, Example 7 is Comparative Example 9, Example 8 is Comparative Example 10, and Example 10 is Comparative Example 11.

[0055] (2) Attenuation (tanδ)

[0056] The dynamic viscoelasticity of each sample was measured in accordance with JIS K7244-10 to obtain tan δ at 25° C. and 10 Hz. A tan δ of 0.5 or more was judged as acceptable (○), and a tan δ of less than 0.5 was judged as unacceptable (×).

[0057] (3) Elastic modulus (complex elastic modulus G ＊ )

[0058] The dynamic viscoelasticity of each sample was measured in accordance with JIS K7244-10 to obtain the complex elastic modulus G at 25°C and 10 Hz. ＊ .

[0059] [Example 1]

[0060] 0.60 g of the product of Shin-Etsu Chemical Co., Ltd. with the product model X-22-167C (mercaptan equivalent: 0.4348 mmol / g) as the organopolysiloxane (A1), 0.93 g of the product of Shin-Etsu Chemical Co., Ltd. with the product model KF-2001 (mercaptan equivalent: 0.5263 mmol / g, hereinafter referred to as component A2-1 in the following table) as the organopolysiloxane (A2), 18.07 g of the product of Gelest Inc. with the product model DMS-V33 (vinyl equivalent: 0.0465 mmol / g, hereinafter referred to as component B-1 in the following table) as the organopolysiloxane (B), and 0.40 g of Omnirad 1173 of the product of IGM Resins B.V. as the photoinitiator (C) were put into a plastic container with a lid. The SH / Vi ratio in the constituent components was made 0.89, and the ratio of the number of mercaptoalkyl groups (SH(A1)) in the organopolysiloxane (A1) to the number of aliphatic unsaturated groups (Vi) in the organopolysiloxane (B) (hereinafter referred to as the SH(A1) / Vi ratio) was made 0.31 for the formulation. Using a rotation-revolution mixer (product name: Awa Toriren Taro (Defoaming Taro) (registered trademark) ARE-350, product of THINKY Corporation), after kneading at 2000 rpm for 3 minutes, centrifugal defoaming was carried out at 2200 rpm for 1 minute to obtain the photocurable silicone resin composition of Example 1. For this photocurable silicone resin composition, according to the above-mentioned measurement and evaluation methods, the measurements and evaluations of (1) shear elongation rate, (2) attenuation property, and (3) elastic modulus were carried out.

[0061] [Example 2]

[0062] The components (A1), (A2), (B), and (C) (hereinafter also referred to as each constituent component) in Example 1 were replaced with the formulations shown in Table 1, the SH / Vi ratio was made 0.70, and the SH(A1) / Vi ratio was made 0.31. Otherwise, the same operations as in Example 1 were carried out to obtain the photocurable silicone resin composition of Example 2. For this photocurable silicone resin composition, according to the above-mentioned measurement and evaluation methods, the measurements and evaluations of (1) shear elongation rate, (2) attenuation property, and (3) elastic modulus were carried out.

[0063] [Example 3]

[0064] The constituent components in Example 1 were replaced with the formulations shown in Table 1, the SH / Vi ratio was made 0.99, and the SH(A1) / Vi ratio was made 0.31. Otherwise, the same operations as in Example 1 were carried out to obtain the photocurable silicone resin composition of Example 3. For this photocurable silicone resin composition, according to the above-mentioned measurement and evaluation methods, the measurements and evaluations of (1) shear elongation rate, (2) attenuation property, and (3) elastic modulus were carried out.

[0065] [Example 4]

[0066] The photocurable silicone resin composition of Example 4 was obtained in the same manner as in Example 1 except that the components in Example 1 were replaced with the ratios shown in Table 1 so that the SH / Vi ratio was 0.89 and the SH(A1) / Vi ratio was 0.06. The photocurable silicone resin composition was measured and evaluated for (1) shear elongation, (2) attenuation, and (3) elastic modulus according to the above-mentioned measurement and evaluation methods.

[0067] [Example 5]

[0068] A photocurable silicone resin composition of Example 5 was obtained in the same manner as in Example 1 except that 0.40 g (equivalent to 2.00 wt % relative to the total weight of component (A1), component (A2), component (B) and component (C)) of fumed silica (AEROSIL product, model: R972) was further added as a filler (D). The photocurable silicone resin composition was measured and evaluated for (1) shear elongation, (2) damping property and (3) elastic modulus according to the above-mentioned measurement and evaluation methods.

[0069] [Example 6]

[0070] The organopolysiloxane (A2) in Example 1 was changed to SMS-022 (mercapto equivalent: 0.3286 mmol / g, hereinafter referred to as component A2-2 in the table) produced by Gelest, and the organopolysiloxane (B) was changed to DMS-V22 (vinyl equivalent: 0.2222 mmol / g, hereinafter referred to as component B-2) produced by Gelest, to form the proportions shown in Table 2. The components were blended so that the SH / Vi ratio in the constituent components was 0.89 and the SH(A1) / Vi ratio was 0.10. The same operation as in Example 1 was performed to obtain the photocurable silicone resin composition of Example 6. The photocurable silicone resin composition was measured and evaluated for (1) shear elongation, (2) attenuation and (3) elastic modulus according to the above-mentioned measurement and evaluation methods.

[0071] [Example 7]

[0072] The photocurable silicone resin composition of Example 7 was obtained in the same manner as in Example 6 except that the components in Example 6 were replaced with the ratios shown in Table 2 so that the SH / Vi ratio was 0.80 and the SH(A1) / Vi ratio was 0.09. The photocurable silicone resin composition was measured and evaluated for (1) shear elongation, (2) attenuation, and (3) elastic modulus according to the above-mentioned measurement and evaluation methods.

[0073] [Example 8]

[0074] The same operation as in Example 6 was carried out except that the components in Example 6 were replaced with the ratios shown in Table 2 so that the SH / Vi ratio was 0.99 and the SH(A1) / Vi ratio was 0.10 to obtain a photocurable silicone resin composition of Example 8. The photocurable silicone resin composition was measured and evaluated for (1) shear elongation, (2) attenuation, and (3) elastic modulus according to the above-mentioned measurement and evaluation methods.

[0075] [Example 9]

[0076] The same operation as in Example 6 was carried out except that the components in Example 6 were replaced with the ratios shown in Table 2 so that the SH / Vi ratio was 0.89 and the SH(A1) / Vi ratio was 0.06 to obtain a photocurable silicone resin composition of Example 9. The photocurable silicone resin composition was measured and evaluated for (1) shear elongation, (2) attenuation, and (3) elastic modulus according to the above-mentioned measurement and evaluation methods.

[0077] [Example 10]

[0078] A photocurable silicone resin composition of Example 10 was obtained in the same manner as in Example 6 except that 0.40 g (corresponding to 2.04 wt % relative to the total weight of component (A1), component (A2), component (B) and component (C)) of fumed silica (AEROSIL product, model: R972) was further added as a filler (D). The photocurable silicone resin composition was measured and evaluated for (1) shear elongation, (2) damping property and (3) elastic modulus according to the above-mentioned measurement and evaluation methods.

[0079] [Comparative Example 1]

[0080] The same procedures as in Example 1 were carried out except that the components in Example 1 were replaced with the ratios shown in Table 3, component (A1) was not contained, the SH / Vi ratio was 0.89, and the SH(A1) / Vi ratio was 0.00, to obtain a photocurable silicone resin composition of Comparative Example 1. The photocurable silicone resin composition was measured and evaluated for (1) shear elongation, (2) attenuation, and (3) elastic modulus according to the above-mentioned measurement and evaluation methods.

[0081] [Comparative Example 2]

[0082] The same operation as in Comparative Example 1 was carried out except that the components in Comparative Example 1 were replaced with the ratios shown in Table 3 so that the SH / Vi ratio was 0.70 to obtain a photocurable silicone resin composition of Comparative Example 2. The photocurable silicone resin composition was measured and evaluated for (1) shear elongation, (2) attenuation, and (3) elastic modulus according to the above-mentioned measurement and evaluation methods.

[0083] [Comparative Example 3]

[0084] The same operation as in Comparative Example 1 was carried out except that the components in Comparative Example 1 were replaced with the ratios shown in Table 3 so that the SH / Vi ratio was 0.99 to obtain a photocurable silicone resin composition of Comparative Example 3. The photocurable silicone resin composition was measured and evaluated for (1) shear elongation, (2) attenuation, and (3) elastic modulus according to the above-mentioned measurement and evaluation methods.

[0085] [Comparative Example 4]

[0086] In Comparative Example 1, except that fumed silica (AEROSIL product, model: R972) was further added as a filler (D), and the components were replaced with the ratios shown in Table 3 so that the SH / Vi ratio was 0.89, the same operation as in Comparative Example 1 was carried out to obtain a photocurable silicone resin composition of Comparative Example 4. The photocurable silicone resin composition was measured and evaluated for (1) shear elongation, (2) attenuation, and (3) elastic modulus according to the above-mentioned measurement and evaluation methods.

[0087] [Comparative Example 5]

[0088] The same operation as in Example 1 was carried out except that the components in Example 1 were replaced with the ratios shown in Table 3 so that the SH / Vi ratio was 0.67 and the SH(A1) / Vi ratio was 0.30, to obtain a photocurable silicone resin composition of Comparative Example 5. The photocurable silicone resin composition was measured and evaluated for (1) shear elongation, (2) attenuation, and (3) elastic modulus according to the above-mentioned measurement and evaluation methods.

[0089] [Comparative Example 6]

[0090] The same operation as in Example 1 was carried out except that the components in Example 1 were replaced with the ratios shown in Table 3 so that the SH / Vi ratio was 1.05 and the SH(A1) / Vi ratio was 0.31, to obtain a photocurable silicone resin composition of Comparative Example 6. The photocurable silicone resin composition was measured and evaluated for (1) shear elongation, (2) attenuation, and (3) elastic modulus according to the above-mentioned measurement and evaluation methods.

[0091] [Comparative Example 7]

[0092] The same operation as in Example 1 was carried out except that the components in Example 1 were replaced with the ratios shown in Table 3 so that the SH / Vi ratio was 0.89 and the SH(A1) / Vi ratio was 0.05, to obtain a photocurable silicone resin composition of Comparative Example 7. The photocurable silicone resin composition was measured and evaluated for (1) shear elongation, (2) attenuation, and (3) elastic modulus according to the above-mentioned measurement and evaluation methods.

[0093] [Comparative Example 8]

[0094] The same procedures as in Example 6 were carried out except that the components in Example 6 were replaced with the ratios shown in Table 4, component (A1) was not contained, the SH / Vi ratio was 0.89, and the SH(A1) / Vi ratio was 0.00, to obtain a photocurable silicone resin composition of Comparative Example 8. The photocurable silicone resin composition was measured and evaluated for (1) shear elongation, (2) attenuation, and (3) elastic modulus according to the above-mentioned measurement and evaluation methods.

[0095] [Comparative Example 9]

[0096] A photocurable silicone resin composition of Comparative Example 9 was obtained in the same manner as in Comparative Example 8 except that the components in Comparative Example 8 were replaced with the ratios shown in Table 4 so that the SH / Vi ratio was 0.80. The photocurable silicone resin composition was measured and evaluated for (1) shear elongation, (2) attenuation, and (3) elastic modulus according to the above-mentioned measurement and evaluation methods.

[0097] [Comparative Example 10]

[0098] The photocurable silicone resin composition of Comparative Example 10 was obtained in the same manner as in Comparative Example 8 except that the components in Comparative Example 8 were replaced with the ratios shown in Table 4 so that the SH / Vi ratio was 0.99. The photocurable silicone resin composition was measured and evaluated for (1) shear elongation, (2) attenuation, and (3) elastic modulus according to the above-mentioned measurement and evaluation methods.

[0099] [Comparative Example 11]

[0100] A photocurable silicone resin composition of Comparative Example 11 was obtained in the same manner as in Comparative Example 8 except that fumed silica (AEROSIL product, model: R972) was further added as a filler (D) in Comparative Example 8 and the components were replaced with the ratios shown in Table 4 so that the SH / Vi ratio was 0.89. The photocurable silicone resin composition was measured and evaluated for (1) shear elongation, (2) attenuation, and (3) elastic modulus according to the above-mentioned measurement and evaluation methods.

[0101] [Comparative Example 12]

[0102] The same operation as in Example 6 was carried out except that the components in Example 6 were replaced with the ratios shown in Table 4 so that the SH / Vi ratio was 0.69 and the SH(A1) / Vi ratio was 0.09 to obtain a photocurable silicone resin composition of Comparative Example 12. The photocurable silicone resin composition was measured and evaluated for (1) shear elongation, (2) attenuation, and (3) elastic modulus according to the above-mentioned measurement and evaluation methods.

[0103] [Comparative Example 13]

[0104] The same operation as in Example 6 was carried out except that the components in Example 6 were replaced with the ratios shown in Table 4 so that the SH / Vi ratio was 1.05 and the SH(A1) / Vi ratio was 0.10, to obtain a photocurable silicone resin composition of Comparative Example 13. The photocurable silicone resin composition was measured and evaluated for (1) shear elongation, (2) attenuation, and (3) elastic modulus according to the above-mentioned measurement and evaluation methods.

[0105] [Comparative Example 14]

[0106] The same operation as in Example 6 was carried out except that the components in Example 6 were replaced with the ratios shown in Table 4 so that the SH / Vi ratio was 0.89 and the SH(A1) / Vi ratio was 0.05, thereby obtaining a photocurable silicone resin composition of Comparative Example 14. The photocurable silicone resin composition was measured and evaluated for (1) shear elongation, (2) attenuation, and (3) elastic modulus according to the above-mentioned measurement and evaluation methods.

[0107] The evaluation results of Examples 1 to 5 are shown in Table 1, and the evaluation results of Examples 6 to 10 are shown in Table 2. In addition, the evaluation results of Comparative Examples 1 to 7 are shown in Table 3, and the evaluation results of Comparative Examples 8 to 14 are shown in Table 4.

[0108]

Table 1

[0109]

[0110]

Table 2

[0111]

[0112]

Table 3

[0113]

[0114]

Table 4

[0115]

[0116] From the results of Examples 1 to 10, it can be seen that the photocurable silicone resin composition of the present invention comprises: a linear organopolysiloxane (B) containing an aliphatic unsaturated group at least at both ends, an organopolysiloxane (A1) containing a mercaptoalkyl group at both ends which functions as a chain extender for the organopolysiloxane (B), an organopolysiloxane (A2) containing a mercaptoalkyl group bonded to a silicon atom which functions as a curing agent for crosslinking the organopolysiloxane (B), and a photopolymerization initiator (C), and by setting the SH / Vi ratio to be greater than or equal to 0.70 and less than 1.00 and the SH(A1) / Vi ratio to be greater than or equal to 0.06, a photocurable silicone resin composition having high attenuation and excellent shear elongation can be obtained. In addition, the complex elastic modulus G of the groups of Examples 1 to 5 and the groups of Examples 6 to 10 is greater than or equal to 0.70 and less than 1.00. ＊ As a result, it is understood that even in the case of a cured product composed only of an organopolysiloxane polymer, the complex elastic modulus of the cured product can be widely designed.

[0117] In addition, the results of Examples 5 and 10 show that the shear elongation is excellent even in the configuration containing the filler (D), and a high elongation improvement rate is shown. In addition, the comparison of the results of Examples 1 to 5 and Examples 6 to 10 shows that the effects of the present invention can be obtained even when the types of the organopolysiloxane (A2) and the organopolysiloxane (B) are changed.

[0118] On the other hand, from the comparison of the results of Examples 1 to 4 with the results of Comparative Examples 1 to 4, and from the comparison of the results of Examples 6 to 9 with the results of Comparative Examples 8 to 11, it can be seen that even under the same conditions of the components and the SH / Vi ratio, when the organopolysiloxane (A1) having a mercaptoalkyl group at both ends that functions as a chain extender for the organopolysiloxane (B) is not contained, the measured values ​​of the shear elongation and the measured values ​​of the attenuation (tan δ) are poor, and both the shear elongation and the attenuation cannot be achieved. In addition, according to the results of the comparative examples, the elastic modulus (G ＊) also becomes larger, indicating that the designable range of the complex elastic modulus of the cured product is limited. In addition, it can be seen from the results of Comparative Examples 5 and 12 that when the SH / Vi ratio is less than 0.70, the crosslinking by the thiol-ene reaction is insufficient and not cured, and it can be seen from the results of Comparative Examples 6 and 13 that when the SH / Vi ratio is greater than or equal to 1.00, good attenuation cannot be obtained. In addition, it can be seen from the results of Comparative Examples 7 and 14 that when the SH(A1) / Vi ratio is less than 0.06, the shear elongation cannot be improved. It can be seen from these results that it is important that, in the combination of the constituent components, the SH(A1) / Vi ratio is greater than or equal to 0.06, and the SH / Vi ratio is greater than or equal to 0.70 and less than 1.00.

[0119]

Industrial Applicability

[0120] The photocurable silicone resin composition of the present invention forms a cured product having a wide designable range of complex elastic modulus, high attenuation, and excellent shear elongation. Therefore, it can be used as, for example, a sealing material for electrical and electronic components, a coating material for sensors, a potting material, a damping material, and an optical adhesive (OCR, OCA) for image display devices. It is particularly suitable for use in narrow space parts in small electrical and electronic products.

Claims

1. A photocurable silicone resin composition comprising: an organopolysiloxane (A) containing a mercaptoalkyl group, a linear organopolysiloxane (B) containing an aliphatic unsaturated group at least at both ends, and a photopolymerization initiator (C), characterized in that: The organopolysiloxane (A) is composed of an organopolysiloxane (A1) containing a mercaptoalkyl group at both ends and an organopolysiloxane (A2) containing two or more mercaptoalkyl groups bonded to silicon atoms per molecule, The ratio of the number of mercaptoalkyl groups in the organopolysiloxane (A) to the number of aliphatic unsaturated groups in the organopolysiloxane (B) is greater than or equal to 0.70 and less than 1.00, and The ratio of the number of mercaptoalkyl groups in the organopolysiloxane (A1) to the number of aliphatic unsaturated groups in the organopolysiloxane (B) is 0.06 or more.

2. The photocurable silicone resin composition according to claim 1, characterized in that: The content of the photopolymerization initiator (C) is 0.05 to 50 parts by mass relative to 100 parts by mass of the organopolysiloxane (B).

3. The photocurable silicone resin composition according to claim 1 or 2, characterized in that: A filler (D) is also included.

4. The photocurable silicone resin composition according to claim 3, characterized in that: The filler (D) is at least one substance selected from the group consisting of silica, silicone resin, solid resin, fibrous compound and metal oxide.

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