Curable silicone composition and cured product therefrom

Abstract

[Problem] To provide: a curable silicone composition giving cured objects which exhibit high hardness and mechanical strength (including tensile strength and elongation) at around room temperature and exhibit excellent viscoelastic characteristics, such as stress-attenuating properties, vibration-absorbing properties, and impact-absorbing properties; and a use of the curable silicone composition. [Solution] Provided is a curable silicone composition characterized by: comprising, in amounts within specific mass% ranges, (A) an organopolysiloxane resin having no curing-reactive functional group, (B) a chain organopolysiloxane having a curing-reactive functional group, and (C) an organopolysiloxane having, in an amount exceeding 10 mass% in the molecule at a molecular end, a curing-reactive functional group containing a carbon-carbon double bond, and further containing (D) a curing agent, the amount of the curing-reactive functional group containing a carbon-carbon double bond being 2.0 mol% or larger per 100 g of the composition; and giving a cured object which has a glass transition temperature between -30°C and 120°C and has a storage elastic modulus at 25°C of 0.5 MPa or greater. Also provided are a cured object of the curable silicone composition, and a use of the cured object in semiconductor devices, etc.

Description

Curable silicone composition and its cured product

[0001] The present invention relates to a curable silicone composition and its cured product, which, upon curing, has a very high tangent loss value at 25°C and sufficient hardness and elongation, thereby forming a cured product with excellent stress damping, vibration absorption, and shock absorption properties. Furthermore, the present invention relates to applications of the composition or its cured product (particularly including vibration absorbing members, shock absorbing members, display device components, and electronic device components containing semiconductors that require stress damping).

[0002] Curable silicone compositions are widely used in various industrial fields because they can cure into cured products with excellent heat resistance, cold resistance, electrical insulation, weather resistance, water repellency, and transparency. These cured silicone products are generally less prone to discoloration and exhibit less deterioration of physical properties over time compared to other organic materials, making them suitable for applications exposed to extreme heat and light.

[0003] Furthermore, while some silicone cured products exhibit excellent properties in stress damping, shock absorption, and vibration absorption in addition to the aforementioned heat resistance and light resistance (for example, Patent Documents 1 and 2), most of these cured products are extremely soft and have a sticky surface, limiting their applicable uses. It has also been found that attempting to increase the hardness of the cured product to suppress surface tack, as in Patent Document 3, results in the loss of the property of damping externally applied forces.

[0004] On the other hand, in Patent Document 4, the applicant has proposed a curable silicone composition that can form a relatively hard cured product while exhibiting stress damping characteristics by combining three types: a resinous polyorganosiloxane containing alkenyl groups, a resinous polyorganosiloxane not containing alkenyl groups, and a linear polyorganosiloxane containing alkenyl groups. However, these cured products are not intended to maximize stress damping characteristics at room temperature.

[0005] Furthermore, in Patent Document 5, the applicant has proposed a liquid curable silicone composition that exhibits relatively low viscosity by using components with low molecular weights among the three components described in the preceding paragraph. These compositions also form cured products that balance stress damping properties with a certain degree of hardness, but it has been found that these cured products do not exhibit sufficient strength.

[0006] Furthermore, there are many applications where materials used for stress absorption and shock absorption need to maximize their properties at or near room temperature. To achieve this, it is necessary to satisfy both a relatively high modulus of elasticity at room temperature (25°C) and a tangent loss value, which is the ratio of the maximized storage modulus to the loss modulus of elasticity. However, no known silicone material is known to satisfy both of these properties.

[0007] Japanese Patent Publication No. 2024-517120, International Publication No. 2018 / 056297, Japanese Patent Publication No. 2007-131694, International Publication No. 2020 / 203304, International Publication No. 2022 / 138336

[0008] The present invention was made to solve the above problems, and the object of the present invention is to provide a curable silicone composition and its applications, in which the resulting cured product exhibits high hardness and mechanical strength (including tensile strength and elongation) at or near room temperature, and also exhibits excellent viscoelastic properties such as stress damping, vibration absorption, and shock absorption.

[0009] As a result of diligent research, the present inventors have found that the above problems can be solved by using a curable silicone composition, its cured product, and its use in stress damping members, shock and vibration absorbing members, display members, semiconductor and other electronic device members, etc., the present invention, characterized in that the curable silicone composition contains an organopolysiloxane resin without curing-reactive functional groups containing carbon-carbon double bonds, a chain organopolysiloxane having such curing-reactive functional groups, an organopolysiloxane having curing-reactive functional groups at the molecular chain ends containing more than 10% by mass of carbon-carbon double bonds in the molecule, in a specific mass% range, and also contains a curing agent, and the amount of curing-reactive functional groups containing carbon-carbon double bonds in 100 g of the composition excluding solid fillers and solvents is 2.0 mol% or more, and the cured product obtained by curing the composition exhibits a glass transition temperature between -30 and 120°C and a storage modulus of 0.5 MPa or more at 25°C, and the cured product thereof exhibits a storage modulus of 0.5 MPa or more.

[0010] The cured product made from the curable silicone composition of the present invention exhibits high hardness and mechanical strength (including tensile strength and elongation), and has a very high tangent loss value at 25°C, thus exhibiting excellent viscoelastic properties such as stress damping, vibration absorption, and shock absorption. For this reason, the cured product made from the curable silicone composition of the present invention can be suitably applied to applications that require damping and absorption of externally applied forces. Such applications include vibration and shock absorbing members such as dampers and speakers. It can also be used as a component for electronic devices containing semiconductors that require large-area bonding or sealing.

[0011] The embodiments of the present invention will be described in detail below.

[0012] [Curable Silicone Composition] The curable silicone composition according to the present invention (A) does not have a curing-reactive functional group containing a carbon-carbon double bond in the molecule, and SiO ４／２(B) an organopolysiloxane resin containing at least 20 mol% or more of siloxane units represented by (A) of the total siloxane units, (C) a linear or branched organopolysiloxane having at least two curing-reactive functional groups containing carbon-carbon double bonds in the molecule and being liquid or plastic at 25°C, (D) an organopolysiloxane having curing-reactive functional groups at the molecular chain ends and containing more than 10% by mass of carbon-carbon double bonds in the molecule, (D) one or more curing agents necessary for curing the composition in an amount sufficient to cure the composition. The composition comprises at least the following, and when the total sum of the entire composition excluding the solid filler and solvent is taken as 100% by mass, the content of component (A) is in the range of 45 to 80% by mass, the content of component (B) is in the range of 20 to 55% by mass, the content of component (C) is in the range of 2 to 15% by mass, and the amount of curing-reactive functional groups containing carbon-carbon double bonds in 100 g of the composition excluding the solid filler and solvent is 2.0 mol% or more, and the cured product obtained by curing the composition exhibits a glass transition temperature between -30 and 120°C and a storage modulus of 0.5 MPa or more at 25°C. The composition may optionally contain (E) a functional filler (preferably one or more fillers selected from reinforcing fillers, white pigments, thermally conductive fillers, conductive fillers, or organic fillers) to impart further functionality to the cured product. Other additives may also be included as long as they do not impair the technical effects of the present invention.

[0013] [Organopolysiloxane resin (A) without curing-reactive functional groups] Component (A) is one of the main components of this composition and does not have curing-reactive functional groups containing carbon-carbon double bonds, and is SiO ４／２ This organopolysiloxane resin contains at least 20 mol% or more of the siloxane units represented by the formula, based on the total siloxane units. By using component (A) in combination with the entire composition within a predetermined quantitative range, it is possible to impart excellent properties such as stress damping, vibration absorption, and shock absorption to the resulting cured product.

[0014] Component (A) does not contain a curing-reactive functional group containing a carbon-carbon double bond such as an alkenyl group in the molecule, while preferably containing a monovalent hydrocarbon group having 1 to 10 carbon atoms and not having a carbon-carbon double bond, particularly a functional group selected from alkyl groups and aryl groups having 1 to 10 carbon atoms such as a methyl group. On the other hand, for component (A), the proportion of aryl groups such as phenyl groups in all silicon-bonded organic groups is preferably in the range of 0 to 5 mol%, more preferably in the range of 0 to 2 mol%, and most preferably not containing any aryl groups (= 0 mol%). When the content of aryl groups in component (A) exceeds the above upper limit, component (A) becomes hot-meltable, making it difficult to obtain the desired liquid composition. In addition, the reinforcing effect of the cured product derived from the siloxane unit represented by ４／２ SiO may decrease, and the color resistance of the cured product at high temperatures may deteriorate.

[0015] Preferably, 70 to 100 mol% of the organic groups bonded to the silicon atoms in component (A) are methyl groups, more preferably 80 to 100 mol% are methyl groups, and particularly preferably 88 to 100 mol% are methyl groups. In such a range, component (A) can be a component particularly excellent in the reinforcing effect of the cured product containing the siloxane unit represented by ４／２ SiO. The organopolysiloxane resin of component (A) may contain a small amount of hydroxyl groups or alkoxy groups.

[0016] Component (A) is an organopolysiloxane resin and is characterized by containing at least 20 mol% or more of the siloxane unit represented by ４／２ SiO in all siloxane units. Preferably, the organopolysiloxane of component (A) has the ４／２ unit being at least 40 mol% or more, particularly preferably 50 mol% or more, especially in the range of 50 to 65 mol% of all siloxane units.

[0017] Preferably, component (A) is (A1) the following average unit formula: (R ３ ３ SiO １／２ ), ａ (R３ ２ SiO ２／２ ) ｂ (R ３ SiO ３／２ ) ｃ (SiO ４／２ ) ｄ (R ２ O １／２）ｅ (In the formula, each R ３ R is a monovalent hydrocarbon group that independently has 1 to 10 carbon atoms and does not contain a carbon-carbon double bond; ２ The organopolysiloxane resin is represented as follows: a is an alkyl group having a hydrogen atom or 1 to 10 carbon atoms; a, b, c, d, and e are numbers satisfying the following: 0.35 ≤ a ≤ 0.55, 0 ≤ b ≤ 0.20, 0 ≤ c ≤ 0.20, 0.30 ≤ d ≤ 0.65, 0 ≤ e ≤ 0.05, and a + b + c + d + e = 1.

[0018] In the above average unit formula, R ２ R is an alkyl group having a hydrogen atom or 1 to 10 carbon atoms. ２ Base R including ２ O １／２ This corresponds to a hydroxyl group or alkoxy group possessed by the organopolysiloxane resin of component (A). Preferably, R ２ R is a hydrogen atom or a methyl group. ３ R is a monovalent hydrocarbon group that independently has 1 to 10 carbon atoms and does not contain a carbon-carbon double bond, such as an alkyl group like methyl. Here, the total R in one molecule ３ It is particularly preferable, from the standpoint of industrial production and the technical effects of the invention, that 70 mol% or more, more preferably 88 mol% or more, be alkyl groups having 1 to 10 carbon atoms, such as methyl groups, especially methyl groups. On the other hand, R ３ It is preferable that the compound substantially does not contain aryl groups such as phenyl groups.

[0019] In the above formula, a is the general formula: R ３ ３ SiO １／２This number represents the proportion of siloxane units. 'a' satisfies 0.35 ≤ a ≤ 0.55, preferably 0.40 ≤ a ≤ 0.50. If 'a' is within this range, the cured product made from a curable silicone composition containing this component can be imparted with excellent mechanical strength and viscoelastic properties.

[0020] In the above formula, b is the general formula: R １ ２ SiO ２／２ This is a number that indicates the proportion of siloxane units. b satisfies 0 ≤ b ≤ 0.20, preferably 0 ≤ b ≤ 0.10. If b is below the upper limit of the range, the hardness of the cured product obtained from the curable silicone composition containing this component will not be too low. In the present invention, b may be 0, and it is preferable that b is 0.

[0021] In the above formula, c is the general formula: R １ SiO ３／２ This number represents the proportion of siloxane units. c satisfies 0 ≤ c ≤ 0.20, preferably 0 ≤ c ≤ 0.10. If c is below the upper limit of the range, the resulting cured product can be given excellent mechanical strength. In the present invention, c may be 0, and it is preferable that c is 0.

[0022] In the above formula, d is SiO ４／２ This number represents the proportion of siloxane units, and is preferably 0.30 ≤ d ≤ 0.65, and particularly preferably 0.50 ≤ d ≤ 0.65. When d is within this numerical range, the cured product obtained by curing a curable silicone composition containing this component can be imparted with excellent mechanical strength and viscoelastic properties.

[0023] In the above formula, e is the general formula: R ２ O １／２ This number represents the proportion of units, where each unit means a hydroxyl group or alkoxy group bonded to a silicon atom that may be contained in the organopolysiloxane resin. e satisfies 0 ≤ e ≤ 0.05, preferably 0 ≤ e ≤ 0.03. In the above formula, the sum of a, b, c, d, and e, which are the sums of each siloxane unit, is equal to 1.

[0024] The amount of component (A) added is in the range of 45 to 80% by mass, preferably 45 to 70% by mass, when the total amount of the entire composition excluding the solid filler and solvent is taken as 100% by mass. When the amount of component (A) is in the above range, the resulting cured product has a very high tangent loss value at 25°C and can be imparted with excellent mechanical strength and viscoelastic properties. The total amount of the entire composition excluding the solid filler and solvent means the solid silicone forming component including the above-mentioned components (A) to (D) and other optional additives, excluding solid fillers such as the functional filler (E) described later and solvents that do not form solid silicone components. If the other optional component is a curing retarder described later, the "total amount of the entire composition excluding the solid filler and solvent" is the value when the total amount of the above-mentioned components (A) to (D) and curing retarder is taken as 100% by mass. The same applies hereinafter in the composition according to the present invention.

[0025] [Component (B)] Component (B) is one of the main components of this curable silicone composition, and is a linear or branched organopolysiloxane that is liquid or plastic at 25°C and has a curing-reactive functional group containing at least two carbon-carbon double bonds in its molecule. Such a curing-reactive linear organopolysiloxane can impart mechanical strength to the resulting cured product when used in combination with the organopolysiloxane resin, which is component (A) described above.

[0026] Component (B) must have a curing-reactive functional group having a carbon-carbon double bond within its molecule. Such a curing-reactive functional group has hydrosilylation reactivity and forms a cured product through crosslinking reactions with other components. Such a curing-reactive functional group is preferably an alkenyl group, particularly a vinyl group or a hexenyl group.

[0027] Component (B) is a linear organopolysiloxane that is liquid or plastic at 25°C (room temperature) and plays an important role in controlling the mechanical strength and permanent elongation properties of the present invention. The chemical structure of the organopolysiloxane of component (B) is preferably the following structural formula: (B1) R ４ ３ SiO(SiR)４ ２ O) ｋ SiR ４ ３ (In the formula, each R ４ R is a monovalent hydrocarbon group having 1 to 10 carbon atoms independently, provided that R in one molecule ４ The linear diorganopolysiloxane is represented by (at least two of which are alkenyl groups, and k is a number between 400 and 10,000). Preferably, the linear diorganopolysiloxane has one alkenyl group, particularly a vinyl group, at each end of the molecular chain.

[0028] In the above formula, each R ４ R is a group selected from the group consisting of a monovalent hydrocarbon group having 1 to 10 carbon atoms, such as an alkyl group such as methyl, particularly preferably a methyl group; an alkenyl group such as vinyl, particularly preferably a vinyl group and / or a hexenyl group; an aryl group such as phenyl; or an aralkyl group such as benzyl. Furthermore, R in one molecule ４ At least two of them are alkenyl groups, preferably vinyl groups. Also, each R ４ It is preferable that the functional group is selected from the group consisting of alkyl groups having 1 to 10 carbon atoms, such as methyl groups, and alkenyl groups, such as vinyl groups and hexenyl groups, and all R ４ Of these, at least two per molecule are alkenyl groups, and the remaining R ４ It is preferable that R is a methyl group. Furthermore, from the viewpoint of the technical effects of the invention, ４ It is preferable that it substantially does not contain aryl groups such as phenyl groups. If it contains a large amount of aryl groups such as phenyl groups, the color resistance of the cured product obtained from the curable silicone composition at high temperatures may deteriorate. Particularly preferable is having one alkenyl group such as a vinyl group at each end of the molecular chain, and other R ４ It is preferable that the group is a methyl group.

[0029] In the above formula, k is preferably 400 or more; if it is lower, the resulting cured product tends to have lower mechanical strength. The value of k can be set arbitrarily, but as it increases, the viscosity of the composition of the present invention increases, so it is necessary to select it as needed.

[0030] Here, the amount of component (B) added is in the range of 20 to 55% by mass, preferably 20 to 50% by mass, when the total amount of the entire composition excluding the solid filler and solvent is taken as 100% by mass. By setting the amount of component (B) added within this range, it is possible to balance the mechanical strength, hardness, and viscoelastic properties of the composition of the present invention at room temperature. [Component (C)] Component (C) is an organopolysiloxane having a curing-reactive functional group (typically an alkenyl group) containing more than 10% by mass of carbon-carbon double bonds in the molecule. Its structure can be linear, branched, cyclic, or any other structure, and the position of the curing-reactive functional group can be at the molecular end or intramolecular. The curing-reactive functional group is preferably an alkenyl group, and specific examples include vinyl groups, allyl groups, hexenyl groups, etc. The composition may be liquid or solid at room temperature, but since the molecular weights of components (A) and (B), which are the main components of the present invention, are relatively high and the composition tends to be highly viscous, it is preferable that component (C) has a low molecular weight and low viscosity.

[0031] Component (C) contains a large amount of reactive functional groups at high density within its molecule, so it can effectively increase the concentration of curing-reactive functional groups without adding a large amount to the composition. Furthermore, if a large amount is added to the composition, the intermolecular crosslinking density increases unnecessarily, and the resulting cured product tends to become brittle. Therefore, in order to obtain a cured product that has a very high tangent loss value at 25°C after curing, and has sufficient hardness and elongation, and exhibits stress and shock absorption, and possesses practical mechanical strength for use as an adhesive, sealant, component for electronic devices including semiconductors, or component for optoelectronic devices, the content of component (C) is preferably in the range of 2 to 15% by mass when the total sum of the entire composition excluding solid fillers and solvents is taken as 100% by mass. Within this range, it is possible to add sufficient amounts of components (A) and (B) to the entire composition, and it is possible to maximize the mechanical strength, hardness, and viscoelastic properties of the resulting cured product.

[0032] Component (C) may be any origanopolysiloxane compound with any structure as long as it satisfies the above conditions, but preferably (R １３ SiO １／２ ) ａ´ (R ２ ２ SiO ２／２ ) ｂ´ (R ２ SiO ３／２ ) ｃ´ (SiO ４／２ ) ｄ´ (R ３ O １／２ ) ｅ´ (In the formula, each R １ R is a monovalent hydrocarbon group having 1 to 10 carbon atoms independently, provided that the total R in one molecule １ At least two of them are alkenyl groups, and each R ２ Each R is an independent monovalent hydrocarbon group having 1 to 10 carbon atoms and not containing an alkenyl group; ３ The branched organopolysiloxane contains 10% by mass or more of an alkenyl group (where is an alkyl group having a hydrogen atom or 1 to 10 carbon atoms) in one molecule and satisfies c' + d' ≥ 0.1.

[0033] In the formula, each R １ , R ２ , R ３ The same groups are independent of each other, and similar groups are exemplified. a', b', c', d', and e' are numbers satisfying the following: 0.40 ≤ a' ≤ 0.80, 0 ≤ b' ≤ 0.90, 0 ≤ c' ≤ 0.60, 0 ≤ d' ≤ 0.50, 0 ≤ e' ≤ 0.05, where a' + b' + c' + d' = 1 and c' + d' ≥ 0.1.

[0034] From the standpoint of efficiently increasing the mechanical strength of the resulting cured product, R in component (C) １ Or R ２ At least three of these are alkenyl groups, and within the molecule, there are more than 10% by mass, preferably in the range of 12 to 40% by mass, R １ Or R ２It is preferable that an alkenyl group is contained therein. When the content of the alkenyl group in the component (C) is within the above range, the hardness can be effectively increased without deteriorating the mechanical strength and viscoelastic properties of the cured product obtained from the curable silicone composition of the present invention. Examples of the alkenyl group in the component (C) include a vinyl group, an allyl group, a butenyl group, a pentenyl group, and a hexenyl group.

[0035] In the formula, a' is a number indicating the ratio of the siloxane unit represented by the general formula: R １ ３ SiO １ / ２ and is a number satisfying 0.40 ≦ a' ≦ 0.90, preferably 0.50 ≦ a' ≦ 0.85. This is because when a' is below the upper limit of the above range, the strength of the obtained cured product is good, and when it is above the lower limit of the lower limit range, the hardness of the cured product can be suitably improved. Further, in the formula, b' is a number indicating the ratio of the siloxane unit represented by the general formula: R ２ ２ SiO ２ / ２ and is a number satisfying 0 ≦ b' ≦ 0.50. This is because when b' is below the upper limit of the above range, the effect of improving the strength of the obtained cured product becomes sufficient. Further, c' is a number indicating the ratio of the siloxane unit represented by the general formula: R ２ SiO ３ / ２ and is a number satisfying 0 ≦ c' ≦ 0.60. This is because when c' is below the upper limit of the above range, the mechanical strength of the obtained cured product becomes good. Further, d' is a number indicating the ratio of the siloxane unit represented by the general formula: SiO ４ / ２ and is a number satisfying 0 ≦ d' ≦ 0.50. This is because when d' is below the upper limit of the above range, the mechanical strength of the obtained cured product is good. Further, e' is a number indicating the ratio of the unit represented by the general formula: R ２ O １ / ２ and is a number satisfying 0 ≦ e' ≦ 0.05. This is because when e' is below the upper limit of the above range, the hardness of the obtained cured product at room temperature is good. In the formula, the sum of a', b', c', and d' is 1, and c' + d' is 0.1 or more.

[0036] Such a (C) component has the above structure and is liquid at room temperature, and is particularly preferred if its viscosity at 25°C is 10,000 mPa·s or less.

[0037] [Component (D)] Component (D) is a curing agent for curing components (B) and (C) described above, and specifically, it is one or more curing agents selected from (d1) or (d2) below. Two or more of these curing agents may be used in combination, for example, a curing system containing both component (d1) and component (d2) may be used. (d1) Organic peroxide (d2) Organohydrogenpolysiloxane having at least two silicon-bonded hydrogen atoms in the molecule and hydrosilylation reaction catalyst

[0038] (d1) The organic peroxide is a component that hardens components (B) and (C) above by heating, and examples include alkyl peroxides, diacyl peroxides, peroxide esters, and peroxide carbonates. Furthermore, it is preferable that the organic peroxide has a half-life of 10 hours at a temperature of 90°C or higher, or 95°C or higher. Examples of such organic peroxides include dicumyl peroxide, di-t-butyl peroxide, di-t-hexyl peroxide, t-butylcumyl peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, 1,3-bis(tert-butylperoxyisopropyl)benzene, di-(2-t-butylperoxyisopropyl)benzene, and 3,6,9-triethyl-3,6,9-trimethyl-1,4,7-triperoxonane.

[0039] (d1) The content of organic peroxide is not limited, but it is preferably in the range of 0.05 to 10 parts by mass or 0.10 to 5.0 parts by mass with respect to the total amount (100 parts by mass) of the composition of the present invention.

[0040] (d2) An organohydrogenpolysiloxane having at least two silicon atom-bonded hydrogen atoms in the molecule and a hydrosilylation reaction catalyst are components that cure the composition by undergoing an addition reaction (hydrosilylation reaction) with the carbon-carbon double bonds in the (B) component and the (C) component in the presence of the hydrosilylation reaction catalyst.

[0041] The structure of the organohydrogenpolysiloxane as the crosslinking agent is not particularly limited and may be linear, branched, cyclic or resinous. That is, the (d2) component has, as a main constituent unit, a hydrogenorganosiloxy unit (D unit, R is independently a monovalent organic group) represented by HR ２ SiO １／２ and may be an organohydrogenpolysiloxane having, at its terminals, a hydrogenorganodisiloxy unit (M unit, R is independently a monovalent organic group) represented by HR Ｈ SiO ２ SiO １／２ In particular, in the case of applications other than the molding process described later, even if the curable silicone composition is a chain organohydrogenpolysiloxane composed of the above D units or the like, practically sufficient curing is possible. Ｈ unit, R is independently a monovalent organic group). Ｈ unit, R is independently a monovalent organic group).

[0042] On the other hand, when the curable silicone composition is used in a molding process, since the density of the curing-reactive functional groups containing carbon-carbon double bonds in the composition tends to be low due to the presence of the (A) component, from the viewpoints of the curing rate, its moldability and curability, the organohydrogenpolysiloxane contains a branched unit which is a monoorganosiloxy unit (T unit, R is a monovalent organic group or a silicon atom-bonded hydrogen atom) represented by RSiO ３／２ or a siloxy unit (Q unit) represented by SiO ４／２ and has, in the molecule, at least two hydrogenorganodisiloxy units (M units, R is independently a monovalent organic group) represented by HR ２ SiO １／２ and is preferably an organohydrogenpolysiloxane resin having an M unit at the molecular terminals. Ｈ unit, R is independently a monovalent organic group). Ｈ unit, R is independently a monovalent organic group).

[0043] Particularly suitable organohydrogenpolysiloxanes are those with the following average unit formula: (R ５ ３ SiO １／２ ) ｌ (R ６ ２ SiO ２／２ ) ｍ (R ６ SiO ３／２ ) ｎ (SiO ４／２ ) ｐ (R ２ O １／２ ) ｑ This is an organohydrogen polysiloxane resin represented by [formula].

[0044] In the formula, each R ５ R is the same or different monovalent hydrocarbon group having 1 to 10 carbon atoms and not having an aliphatic unsaturated carbon bond, or hydrogen atom, provided that there are at least two R in one molecule. ５ R is a hydrogen atom. ５ The monovalent hydrocarbon group is, for example, an alkyl group such as methyl; an aryl group such as phenyl; an aralkyl group such as benzyl; or other halogenated alkyl groups. From an industrial standpoint, a methyl group or a phenyl group is preferred.

[0045] In the formula, R ６ R is a monovalent hydrocarbon group having 1 to 10 carbon atoms that does not have an aliphatic unsaturated carbon bond, and examples of groups similar to the monovalent hydrocarbon group described above are given. On the other hand, R ２ is an alkyl group having a hydrogen atom or 1 to 10 carbon atoms, and R in component (A) above ２ Similar groups are given as examples.

[0046] In the formula, l, m, n, and p are numbers satisfying the following: 0.1 ≤ l ≤ 0.80, 0 ≤ m ≤ 0.5, 0 ≤ n ≤ 0.8, 0 ≤ p ≤ 0.6, 0 ≤ q ≤ 0.05, where n + p > 0.1 and l + m + n + p = 1. Here, when this composition is used in the molding process, the organohydrogenpolysiloxane resin which is part of component (d2) is specifically M Ｈ T resin, M Ｈ MT resin, M Ｈ MTTＨ Resin, M Ｈ MTQ resin, M Ｈ MQ resin, M Ｈ MTT Ｈ Q, M Ｈ Q resin is preferred.

[0047] Particularly preferred is the organohydrogenpolysiloxane, which is part of component (d2), (H(CH) ３ ) ２ SiO １／２ ) ｌ１ (SiO ４／２ ) ｐ１ M Ｈ The material is Q resin. Here, l1 + p1 = 1, and it is preferable that 0.1 ≤ l1 ≤ 0.80 and 0.20 ≤ p1 ≤ 0.90.

[0048] Similarly, organohydrogenpolysiloxane, which is part of component (d2), is (HR ７ ２ SiO １／２ ) ｈ (R ７ ２ SiO ２／２ ) ｉ (R ８ SiO ３／２ ) ｊ It may be so. In the above equation, R ７ and R ８ Each of these is independently an unsubstituted or substituted monovalent hydrocarbon group having 1 to 12 carbon atoms and not containing an aliphatic unsaturated bond, and all R ８ At least 10 mol% of these are aryl groups, and h, i, and j are numbers that satisfy the conditions 0.01 ≤ h ≤ 0.6, 0 ≤ i ≤ 0.9, 0.2 ≤ j ≤ 0.9, and h + i + j = 1. A specific example of this monovalent hydrocarbon group is R in the above average composition formula (1). ４ This is the same as the specific example of a monovalent hydrocarbon group represented by R. ８ is all R ８ Preferably, each group is independently selected from methyl groups and phenyl groups, provided that at least 10 mol% of them are phenyl groups, and if no D units are present, M Ｈ T Ｐｈ It can be made of resin.

[0049] Similarly, the organohydrogenpolysiloxane, which is part of component (d2), may include a linear diorganopolyloxane, organohydrogenpolysiloxane, or diorganopolysiloxane-organohydrogensiloxane copolymer in which the molecular chain ends are sealed by silicon-bonded hydrogen atoms or trimethylsiloxy groups. The degree of siloxane polymerization of these linear organohydrogenpolysiloxanes is not particularly limited, but is in the range of 2 to 200, and preferably in the range of 5 to 100.

[0050] The amount of organohydrogenpolysiloxane, which is part of component (d2), is sufficient to cure the curable silicone composition of the present invention, and is such that the molar ratio of silicon-bonded hydrogen atoms in the organohydrogenpolysiloxane to curing-reactive functional groups containing carbon-carbon double bonds in components (B) and (C) (e.g., alkenyl groups such as vinyl groups) is 0.9 or more, and is preferably in the range of 0.9 to 2.0.

[0051] As a catalyst for the hydrosilylation reaction, which is part of component (d2), examples include platinum-based catalysts, rhodium-based catalysts, and palladium-based catalysts, and platinum-based catalysts are preferred because they can significantly accelerate the curing of the composition. Examples of platinum-based catalysts include platinum fine powder, chloroplatinic acid, an alcoholic solution of chloroplatinic acid, platinum-alkenylsiloxane complexes, platinum-olefin complexes, platinum-carbonyl complexes, and catalysts in which these platinum-based catalysts are dispersed or encapsulated in thermoplastic resins such as silicone resin, polycarbonate resin, and acrylic resin, with platinum-alkenylsiloxane complexes being particularly preferred. In particular, a platinum 1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex is preferred, and it is preferable to add the complex in the form of an alkenylsiloxane solution. In addition, from the viewpoint of improving handling workability and the pot life of the composition, particulate platinum-containing hydrosilylation reaction catalyst dispersed or encapsulated in a thermoplastic resin may be used. Furthermore, non-platinum metal catalysts such as iron, ruthenium, or iron / cobalt may be used as catalysts to promote the hydrosilylation reaction.

[0052] On the other hand, the hydrosilylation catalyst, which is part of component (d2), may be a hydrosilylation catalyst (component (d2-1)) that does not show activity without irradiation with high-energy rays but shows activity in the composition upon irradiation with high-energy rays. Component (d2-1) is a so-called high-energy ray activated catalyst or photoactivated catalyst, and is well known in the art. By using component (d2-1), the entire composition can be cured even at low temperatures triggered by irradiation with high-energy rays, has excellent storage stability, and is easy to control the reaction, thus achieving excellent handling properties.

[0053] High-energy rays include ultraviolet rays, gamma rays, X-rays, alpha rays, and electron beams. In particular, ultraviolet rays, X-rays, and electron beams irradiated from commercially available electron beam irradiation devices are preferred. Among these, ultraviolet rays are preferred from the viewpoint of catalyst activation efficiency, and ultraviolet rays in the wavelength range of 280 to 380 nm are preferred from the viewpoint of industrial use. The irradiation dose varies depending on the type of high-energy ray activated catalyst, but in the case of ultraviolet rays, the cumulative irradiation dose at a wavelength of 365 nm is 100 mJ / cm². ２ ~100 J / cm ２ It is preferable that it be within the range.

[0054] (d2-1)Specific examples of components include (methylcyclopentadienyl)trimethylplatinum (IV), (cyclopentadienyl)trimethylplatinum (IV), (1,2,3,4,5-pentamethylcyclopentadienyl)trimethylplatinum (IV), (cyclopentadienyl)dimethylethylplatinum (IV), (cyclopentadienyl)dimethylacetylplatinum (IV), (trimethylsilylcyclopentadienyl)trimethylplatinum (IV), (methoxycarbonylcyclopentadienyl)trimethylplatinum (IV), (dimethylphenylsilylcyclopentadienyl)trimethylcyclopentadienylplatinum (IV), trimethyl(acetylacetonate)platinum (IV), trimethyl(3,5- Examples include heptanedione) platinum (IV), trimethyl(methylacetoacetate) platinum (IV), bis(2,4-pentanedionato) platinum (II), bis(2,4-hexanedionato) platinum (II), bis(2,4-heptanedionato) platinum (II), bis(3,5-heptanedionato) platinum (II), bis(1-phenyl-1,3-butanedionato) platinum (II), bis(1,3-diphenyl-1,3-propanedionato) platinum (II), and bis(hexafluoroacetylacetonato) platinum (II). Among these, (methylcyclopentadienyl)trimethylplatinum (IV) and bis(2,4-pentanedionato) platinum (II) are preferred in terms of versatility and availability.

[0055] The amount of the hydrosilylation catalyst, which is part of these (d2) components, added is preferably such that the amount of metal atoms is in the range of 0.01 to 500 ppm, 0.01 to 100 ppm, or 0.01 to 50 ppm relative to the total composition by mass.

[0056] Particularly preferred components (d2) include at least an organohydrogenpolysiloxane resin represented by the average unit formula and a hydrosilylation reaction catalyst.

[0057] [Component (E)] If functionality is to be imparted to the cured product obtained from the curable silicone composition of the present invention, a functional filler may be optionally included as component (E) in addition to the above components (A) to (D). In this invention, component (E) is a solid filler and is excluded from the "entire composition excluding solid fillers and solvents" which is the basis for determining the content of components (A) to (C) above.

[0058] Functional fillers, which are optional components, are components that impart mechanical properties and other properties to the cured product, and examples include inorganic fillers, organic fillers, and mixtures thereof. Examples of inorganic fillers include reinforcing fillers, white pigments, thermally conductive fillers, conductive fillers, phosphors, and mixtures of at least two of these, while examples of organic fillers include silicone resin-based fillers, fluororesin-based fillers, and polybutadiene resin-based fillers. The shape of these fillers is not particularly limited and may be spherical, spindle-shaped, flattened, needle-shaped, amorphous, etc.

[0059] When this composition is used in applications such as sealants, protective agents, and adhesives, it may contain reinforcing fillers from the viewpoint of improving the mechanical strength, protective properties, and adhesive properties of the cured product.

[0060] Reinforcing fillers improve the mechanical strength of the cured product, enhance its protective and adhesive properties, and may also be added as binder fillers to maintain the solid particulate state of the curable silicone composition before curing. Examples of such reinforcing fillers include fumed silica, precipitated silica, fused silica, calcined silica, fumed titanium dioxide, quartz, calcium carbonate, diatomaceous earth, aluminum oxide, aluminum hydroxide, zinc oxide, and zinc carbonate. These reinforcing fillers may also be surface-treated with organoalkoxysilanes such as methyltrimethoxysilane; organohalosilanes such as trimethylchlorosilane; organosilazanes such as hexamethyldisilazane; and siloxane oligomers such as α,ω-silanol group-sealed dimethylsiloxane oligomers, α,ω-silanol group-sealed methylphenylsiloxane oligomers, and α,ω-silanol group-sealed methylvinylsiloxane oligomers. The particle size of this reinforcing filler is not limited, but it is preferable that the median diameter measured by laser diffraction scattering particle size distribution measurement is in the range of 1 nm to 500 μm. Furthermore, as the reinforcing filler, fibrous inorganic fillers such as calcium metasilicate, potassium titanate, magnesium sulfate, sepiolite, zonolite, aluminum borate, rock wool, glass fiber, carbon fiber, asbestos fiber, metal fiber, wollastonite, attapulgite, sepiolite, aluminum borate whiskers, potassium titanate fibers, calcium carbonate whiskers, titanium oxide whiskers, and ceramic fibers may be used; fibrous fillers such as aramid fibers, polyimide fibers, and poly(p-phenylenebenzobisoxazole) fibers may also be used. In addition, plate-shaped or granular fillers such as talc, kaolin clay, calcium carbonate, zinc oxide, calcium silicate hydrate, mica, glass flakes, glass powder, magnesium carbonate, silica, titanium dioxide, alumina, aluminum hydroxide, magnesium hydroxide, barium sulfate, calcium sulfate, calcium sulfite, zinc borate, barium metaborate, aluminum borate, calcium borate, sodium borate, aluminum nitride, boron nitride, silicon nitride, or crushed fibrous fillers may be used.Furthermore, the shape of the primary particles of the reinforcing filler is not particularly limited, and fillers having one or more shapes and particle sizes selected from spherical (including perfectly spherical, molten spherical, and rounded), plate-like, fibrous, flaky, and irregular shapes can be used.

[0061] Furthermore, white pigments, thermally conductive fillers, conductive fillers, or phosphors may be added to the cured product obtained using this composition in order to impart other functions to the product. Organic fillers such as silicone microparticles may also be added for purposes such as improving the stress relaxation properties of the cured product.

[0062] The white pigment is a component that imparts whiteness to the cured product and improves its light reflectivity. By incorporating this component, the cured product obtained by curing the composition can be used as a light reflector for light-emitting / optical devices. Examples of this white pigment include metal oxides such as titanium dioxide, aluminum oxide, zinc oxide, zirconium oxide, and magnesium oxide; hollow fillers such as glass balloons and glass beads; and others such as barium sulfate, zinc sulfate, barium titanate, aluminum nitride, boron nitride, and antimony oxide. Titanium dioxide is preferred due to its high light reflectivity and opacity. Aluminum oxide, zinc oxide, and barium titanate are also preferred due to their high light reflectivity in the UV region. The average particle size and shape of this white pigment are not limited, but the average particle size is preferably in the range of 0.05 to 10.0 μm, or in the range of 0.1 to 5.0 μm. Furthermore, this white pigment may be surface-treated with a silane coupling agent, silica, aluminum oxide, etc.

[0063] Thermally conductive fillers or conductive fillers are added to the cured product for the purpose of imparting thermal conductivity / electrical conductivity. Specifically, examples include fine metal powders such as gold, silver, nickel, copper, and aluminum; fine powders of ceramics, glass, quartz, organic resins, etc., on which metals such as gold, silver, nickel, and copper are deposited or plated; metal compounds such as aluminum oxide, magnesium oxide, aluminum nitride, boron nitride, and zinc oxide; graphite; and mixtures of two or more of these. When electrical insulation is required for the composition, metal oxide powders or metal nitride powders are preferred, and aluminum oxide powder, zinc oxide powder, or aluminum nitride powder are particularly preferred. These may be used in combination of type, particle size, particle shape, etc., depending on the requirements for thermal conductivity / electrical conductivity.

[0064] A phosphor is a component added to a cured material to convert the emission wavelength from a light source (optical semiconductor device) when the cured material is used as a wavelength conversion material. There are no particular restrictions on the phosphor, but examples include yellow, red, green, and blue emitting phosphors made from oxide-based phosphors, oxynitride-based phosphors, nitride-based phosphors, sulfide-based phosphors, oxysulfide-based phosphors, etc., which are widely used in light-emitting diodes (LEDs).

[0065] Silicone microparticles include non-reactive silicone resin microparticles and silicone elastomer microparticles, but silicone elastomer microparticles are preferably exemplified from the viewpoint of improving the flexibility or stress relaxation properties of the cured product. The surface of the silicone elastomer particles may be modified with functional groups or coated with silicone resin or the like.

[0066] For the purpose of stably incorporating the above-mentioned functional fillers into this composition, the filler surface may be treated by using a specific surface treatment agent in an amount of 0.1 to 2.0% by mass, 0.1 to 1.0% by mass, or 0.2 to 0.8% by mass relative to the total mass of the filler components. Examples of these surface treatment agents include, for example, methyl hydrogen polysiloxane, silicone resin, metal soap, silane coupling agent, perfluoroalkylsilane, and fluorine compounds such as perfluoroalkyl phosphate salts.

[0067] The content of the functional filler component is not limited, but it is preferable that it be in the range of 1 to 2000 parts by mass, 1 to 1500 parts by mass, or 1 to 1000 parts by mass relative to the sum of components (A) to (D) above (100 parts by mass), in order to obtain a hard and mechanically strong cured product.

[0068] The curable silicone composition of the present invention may further contain a curing retarder in addition to the above components (A) to (D) and optional components. The type of curing retarder is not particularly limited, but examples include alkyne alcohols such as 2-methyl-3-butyne-2-ol, 3,5-dimethyl-1-hexyne-3-ol, 2-phenyl-3-butyne-2-ol, and 1-ethynyl-1-cyclohexanol; enyne compounds such as 3-methyl-3-penten-1-yne and 3,5-dimethyl-3-hexen-1-yne; alkenyl group-containing low molecular weight siloxanes such as tetramethyltetravinylcyclotetrasiloxane and tetramethyltetrahexenylcyclotetrasiloxane; and methyl-tris(1,1-dimethylpropynyl oxyl tetrasiloxane). Examples include alkynyloxysilanes such as silane and vinyl-tris(1,1-dimethylpropynyloxy)silane; and bis(alkynyloxysilyl)alkanes such as 1-[tris(1,1-dimethyl-2-propynyloxy)silyl-6-[bis(1,1-dimethyl-2-propynyloxy)methoxysilyl]hexane, 1,6-bis[tris(1,1-dimethyl-2-propynyloxy)silyl]hexane, or mixtures thereof, as proposed by the applicants in International Publication No. 2023 / 190892 and International Publication No. 2023 / 190893. Of these, it is particularly preferable to use compounds with a boiling point of 200°C or higher at atmospheric pressure. The content of the curing retarder in the curable silicone composition is not particularly limited, but it is preferably in the range of 1 to 10,000 ppm by mass relative to the composition.

[0069] The composition of the present invention may contain an adhesion promoter, provided that it does not impair the purpose of the present invention. Such adhesion promoters are common to the components suitably exemplified by the applicant in International Publication No. 2020 / 203304, and include silane compounds such as 3-glycidoxypropyltrimethoxysilane, organosiloxane oligomers, alkyl silicates, as well as reaction mixtures of amino group-containing organoalkoxysilanes and epoxy group-containing organoalkoxysilanes disclosed in Japanese Patent Publication No. 52-8854 and Japanese Patent Application Publication No. 10-195085. In particular, carbasilatran derivatives having a silicon atom-bonded alkoxy group or a silicon atom-bonded alkenyl group in one molecule, and silatran derivatives having an alkoxysilyl group-containing organic group can be suitably used.

[0070] Furthermore, the composition may contain, as long as it does not impair the purpose of the present invention, other optional components such as iron oxide (red iron oxide), cerium oxide, cerium dimethyl silanolate, cerium fatty acid salts, cerium hydroxide, zirconium compounds, and other heat-resistant agents; as well as dyes, pigments other than white, flame retardants, etc. Note that the composition may use solvents (dispersion media) such as toluene and xylene as dispersion media for components (A) to (C), but as stated above, these solvents are excluded from the "entire composition excluding solid fillers and solvents" which is the basis for determining the content of components (A) to (C).

[0071] The curable silicone composition of the present invention may be liquid, paste, or solid at room temperature. If the composition is liquid or paste, it can be produced by kneading the aforementioned components (A) to (D) and any other component using a known method. The mixing apparatus used for mixing or kneading is not limited, and examples include single-screw or twin-screw continuous mixers, double-roll mixers, Ross mixers, Hobart mixers, Dental mixers, Planetary mixers, Kneader mixers, etc. If the composition is solid, examples include single-screw or twin-screw continuous mixers, double-roll mixers, Kneader mixers, Lab Millsers, small pulverizers, Henschel mixers. If the components used are soluble in organic solvents, it is also possible to produce a solid composition at room temperature by dissolving them in a highly soluble solvent, performing a coating treatment, and then removing the solvent with hot air.

[0072] The curable silicone composition forms a cured product by one of the following methods: thermosetting, high-energy ray curing, or high-energy ray + thermosetting. Therefore, by applying the composition to the substrate to be cured using a coating or dispenser before the curing process, and then curing it, it is possible to form a cured product while simultaneously achieving adhesion to the substrate.

[0073] [Uses of the Composition] The curable silicone composition of the present invention exhibits excellent heat resistance and light resistance similar to ordinary silicone elastomers, while also possessing superior mechanical strength and hardness, and exhibiting excellent viscoelastic properties such as stress damping, vibration absorption, and shock absorption. Therefore, it can be suitably applied to components requiring damping properties, such as dampers and speakers. Furthermore, due to its excellent viscoelastic properties, it can also be suitably applied to bonding and sealing large areas, such as components for electronic devices containing semiconductors. On the other hand, since the hardness of the cured product can be freely controlled by adjusting the composition, compositions that form relatively soft, rubber-elastic cured products can also be used as a stress buffer layer (adhesive layer) between two substrates with different coefficients of linear expansion.

[0074] Furthermore, cured products made from the curable silicone composition of the present invention exhibit good adhesion to difficult-to-bond substrates such as polyphenylene sulfone resins, silicone resins, and fluororesins, and can therefore be used for sealing these substrates or as stress-relieving layers for bonding two different substrates. In other words, the curable silicone composition of the present invention may be a sealant intended for single-sided sealing, or a sealant intended for double-sided sealing involving adhesion between two substrates, and possesses desirable properties suitable for these applications.

[0075] [Curing Conditions for the Composition] As described above, the curable silicone composition of the present invention can be cured by heat curing, high-energy ray curing such as ultraviolet light, or a combination of these, depending on the selection of component (D). In the case of heat curing, curing can generally be rapidly advanced by exposure to a temperature of 100°C or higher, preferably 150°C or higher. In the case of the high-energy ray curing type, curing will proceed by leaving it at room temperature or heating after irradiation with the light. Therefore, applying the composition to the substrate before irradiating with high-energy rays makes it easier to ensure the stability of the liquid composition. After applying this composition to the substrate, it is possible to rapidly cure it at a relatively low temperature of about 80°C to 120°C by irradiating with high-energy rays.

[0076] [Concentration of curing reactive groups containing carbon-carbon double bonds in the composition] The composition of the present invention contains curing reactive groups containing carbon-carbon double bonds derived from its component (B), component (C), and other optional components. In order for the hardness of the resulting cured product to be in the elastomer range, the amount of curing reactive groups must be 2.0 mol% or more per 100 g of the composition excluding the solid filler and solvent, and preferably between 2.0 and 15.0 mol%. In particular, when the composition of the present invention is cured by a hydrosilylation reaction, it is preferable that the content of alkenyl groups, which are curing reactive groups, be 2.0 mol% or more per 100 g of the composition excluding the solid filler and solvent. By setting this range above the lower limit, the resulting cured product will have sufficient crosslinking density, and its hardness can be increased.

[0077] [Physical Properties of Cured Products] As described below, the cured product obtained by curing the curable silicone composition according to the present invention has a specific glass transition temperature and storage modulus at 25°C, and therefore has a very high tangent loss value at 25°C, as well as sufficient hardness and mechanical strength such as elongation. The cured product has excellent physical properties, stress damping properties, vibration absorption properties, and shock absorption properties as viscoelastic properties derived from these physical properties. These physical properties are characteristics of the cured product based on the selection of components (A) to (D) and arbitrary components as described above, and the content of each component within a specific range. (Glass Transition Temperature and Storage Modulus) The glass transition temperature of a cured product is defined as the temperature at which the tangent loss value, which is the ratio of the storage modulus and the loss modulus when the temperature is varied, shows its maximum value. The cured product obtained from the composition of the present invention is characterized by exhibiting a glass transition temperature in the range of -30 to 120°C. If the glass transition temperature is outside this temperature range, the desired very high tangent loss at 25°C may not be achieved, and sufficient viscoelastic properties may not be realized. Furthermore, the cured product obtained from the composition of the present invention has a storage modulus of 0.5 MPa or more at 25°C, preferably in the range of 0.50 to 50.0 MPa, and more preferably in the range of 0.50 to 45.0 MPa. If the storage modulus of the cured product is below the lower limit, viscoelastic properties such as shock absorption may not be realized. (Tangential loss at 25°C) The cured product obtained from the composition of the present invention has a tangent loss (loss modulus / storage modulus) value of 0.30 or more at 25°C, preferably in the range of 0.33 or more, and more preferably in the range of 0.33 to 0.70. If the tangent loss at 25°C is below the lower limit, viscoelastic properties such as shock absorption tend to deteriorate. (Elongation) The cured product obtained from the composition of the present invention preferably has a strain-elongation at fracture obtained by the tensile test of 100% or more, preferably in the range of 200 to 2000%, and more preferably in the range of 300 to 1800%. In addition to the very high tangential loss at 25°C mentioned above, the cured material achieves viscoelastic properties such as shock absorption because, given the assumption of shape changes, the fracture strain is sufficiently high.

[0078] [Applications of Cured Products] The applications of the cured products obtained by curing the curable silicone composition of the present invention are not particularly limited, but because they exhibit relatively high hardness, high toughness, and excellent viscoelastic properties due to very high tangent loss, they can be used as silicone elastomers exhibiting excellent stress damping, vibration absorption, and shock absorption properties. Cured products obtained by curing this composition can be suitably used as components for semiconductor devices and display devices.

[0079] Semiconductor devices and display devices equipped with a component made of a cured product obtained by curing the curable silicone composition of the present invention are not particularly limited, but are particularly suitable for dampers, speakers, etc., due to their excellent vibration absorption and shock absorption properties. Furthermore, are suitable for large-area bonding and sealing due to their excellent stress damping properties. For example, they are preferably used as sealing materials, case materials, or adhesive members for light-emitting semiconductor devices, optical components for displays, components for solar panels, and especially for large-scale versions of these devices. In addition, as an adhesive member, it can also be used as a stress buffer layer (adhesive layer) between two substrates with different coefficients of thermal expansion.

[0080] The curable silicone composition and its manufacturing method of the present invention will be described in detail below with reference to examples and comparative examples. In the following description, Me, Vi, and Ph in the average unit formulas represent methyl group, vinyl group, and phenyl group, respectively. Furthermore, the storage modulus, tensile elongation, glass transition temperature, and tangent loss at 25°C of the curable silicone composition of each example and comparative example were measured by the method described below, and the results are shown in Tables 1 and 2. For compositions using a UV-activated hydrosilylation reaction catalyst (component (c2-2) described later), ultraviolet light with a wavelength of 365 nm was irradiated at a dose of 10 J / cm². ２ The irradiation is performed before heating, in which case the desired result is achieved.

[0081] [Storage Modulus] A curable silicone composition was heated at 150°C for 2 hours to produce a cured product. The storage modulus of this cured product from -50°C to 200°C was measured using a rheometer ARES (manufactured by T.A. Instruments Japan Co., Ltd.), and the value at 25°C was read. Tables 1 and 2 show the measured values ​​at 25°C. [Loss Tangent] A curable silicone composition was heated at 150°C for 2 hours to produce a cured product. The storage modulus and loss modulus of this cured product from -50°C to 200°C were measured using a rheometer ARES (manufactured by T.A. Instruments Japan Co., Ltd.), and the value at 25°C was read. The loss tangent was calculated as loss modulus / storage modulus, and the results are shown in Tables 1 and 2. [Glass Transition Temperature] A curable silicone composition was heated at 150°C for 2 hours to produce a cured product. The storage modulus and loss modulus of this cured product from -50°C to 200°C were measured using a rheometer ARES (manufactured by T.A. Instruments Japan Co., Ltd.). The loss tangent was calculated as loss modulus / storage modulus, and the temperature at which this value was maximized was read as the glass transition temperature. The results are shown in Tables 1 and 2. [Tensile elongation] A curable silicone composition was heated at 150°C for 2 hours to produce a cured product. The tensile elongation of this cured product was measured according to the method specified in JIS K 6251-2010 "Vulcanized rubber and thermoplastic rubber - Method for determining tensile properties," and the results are shown in Table 1.

[0082] The following compounds were used in the examples and comparative examples shown below.

[0083] • Component (a-1): Average unit formula (Me ３ SiO １ / ２ ) ０.４４ (SiO ４ / ２ ) ０.５６ (HO １ / ２ ) ０.０２ Organopolysiloxane resin represented by (vinyl group content = 0 mol%, weight-average molecular weight (Mw) measured by GPC using toluene as a solvent is 18,500) ・Component (a-2): Average unit formula (Me ３ SiO １ / ２ ) ０.４９ (SiO ４ / ２ ) ０.５１(HO １ / ２ ) ０.０２ Organopolysiloxane resin represented by (vinyl group content = 0 mol%, weight-average molecular weight (Mw) measured by GPC using toluene as a solvent is 4,000) ・Comparative component (a-3): Average unit formula (Me ２ Visio １ / ２ ) ０.０８ (Me ３ SiO １ / ２ ) ０.４２ (SiO ４ / ２ ) ０.５０ (HO １ / ２ ) ０.０１ Organopolysiloxane resin represented by (vinyl group content = 3.1 mol%, weight-average molecular weight (Mw) measured by GPC using toluene as a solvent is 4,300) ・Comparative component (a-4): Average unit formula (Me ２ Visio １ / ２ ) ０.０５ (Me ３ SiO １ / ２ ) ０.３９ (SiO ４ / ２ ) ０.５６ (HO １ / ２ ) ０.０２ Organopolysiloxane resin represented by (vinyl group content = 1.9 mol%, weight-average molecular weight (Mw) measured by GPC using toluene as a solvent is 18,000) • Component (b-1): ViMe ２ SiO(Me ２ SiO) ８００ SiViMe ２ Represented as: Dimethylpolysiloxane with dimethylvinylsiloxy groups sealed at both ends of the molecular chain (vinyl group content = 0.09 mol%) • Component (b-2): ViMe ２ SiO(Me ２ SiO) ３００ SiViMe ２ Dimethylpolysiloxane with dimethylvinylsiloxy groups sealed at both ends of the molecular chain (vinyl group content = 0.23 mol%) - Component (c-1): (ViMe ２ SiO １／２ ) ０．８０ (SiO ４／２ ) ０．２０A branched organopolysiloxane with a viscosity of 3 mPa·s and containing vinyl groups at the molecular ends (vinyl group content = 27% by mass) represented by Component (c-2): (Me ２ Visio １ / ２ ) ０.５５ (Me ３ SiO １ / ２ ) ０.０５ (YiO ４ / ２ ) ０.４０ A branched organopolysiloxane with a viscosity of 300 mPa·s and containing vinyl groups at the molecular ends (vinyl group content = 19% by mass) - Component (d1-1): (HMe ２ SiO １ / ２ ) ０.６７ (SiO ４ / ２ ) ０.３３ Organohydrogenpolysiloxane represented by (PhSiO) (Silicon atom bonded hydrogen atom content = 1.0 mass%) • Components (d1-2): Average unit formula: (PhSiO) ３ / ２ ) ０.４ (HMe ２ SiO １ / ２ ) ０.６ Represented as a branched-chain organopolysiloxane having two or more silicon-bonded hydrogen atoms in one molecule (silicon-bonded hydrogen atom content = 0.65 mass %) • Components (d1-3): Me ３ SiO(Me ２ SiO) ３７ (MeHSiO) ３７ SiMe ３ Organohydrogenpolysiloxane represented by (silicon atom bonded hydrogen atom content = 0.7 mass%) • Components (d1-4): Me ３ SiO (MeHSiO) ５５ SiMe ３Organohydrogenpolysiloxane represented by (silicon atom bonded hydrogen atom content = 1.6 mass%) Component (d2-1): Platinum 1,3-divinyl-1,1,3,3-tetramethyldisiloxane solution Component (d2-2): (methylcyclopentadienyl)trimethylplatinum(IV) Component (e-1): Carbon black with an average particle size of 80 nm Component (e-2): Spherical silica with an average primary particle size of 4 μm Component (f-1): Methyltris-1,1-dimethyl-2-propynyloxysilane (boiling point at atmospheric pressure = 245°C) Component (f-2): 1,6-bis[tris(1,1-dimethyl-2-butyneoxy)silyl]hexane (boiling point at atmospheric pressure = 300°C or higher)

[0084] [Examples 1-12, Comparative Examples 1-9] Curable silicone compositions were prepared by mixing each component in the quantities listed in Tables 1 and 2. The cured product (compositions using d2-2 as component D were irradiated with ultraviolet light at a wavelength of 365 nm at a dose of 10 J / cm²) ２ The storage modulus, tangent loss, glass transition temperature, and tensile elongation of the material (cured by applying a predetermined amount of heat after irradiation) were measured using the method described above, and the results are shown in the table.

[0085]

[0086]

[0087] [Summary] The curable silicone compositions of Examples 1 to 12 according to the present invention utilize a vinyl group-free organopolysiloxane resin (a), a chain-like organopolysiloxane containing vinyl groups (b), and a branched organopolysiloxane having a high vinyl content and vinyl groups at its molecular ends (d), within the content range specified in the present invention. This allows for the creation of a glass transition temperature as specified in the present invention, maintaining high levels of hardness and elongation at room temperature while achieving a very high tangent loss at 25°C. The cured product obtained by curing this composition exhibits both excellent mechanical properties and viscoelastic properties, and can be used as a cured product with excellent stress damping, vibration absorption, and shock absorption.

[0088] On the other hand, it was found that the curable silicone compositions of Comparative Examples 1 and 2 had glass transition temperatures that did not fall within the range of the present invention, resulting in low tangent loss at 25°C. The curable silicone compositions of Comparative Examples 3 to 6 and 8 had a small amount of component (A) added, resulting in low tangent loss at 25°C for the resulting cured products. The cured product made from the curable silicone composition of Comparative Example 7 had a glass transition temperature that was too high, resulting in a low tangent loss at 25°C. The curable silicone composition of Comparative Example 9 had a concentration of curing reactive groups that was too low, resulting in a low elastic modulus of the resulting cured product and insufficient viscoelastic properties.

Claims

1. (A) It does not have a hardening-reactive functional group containing a carbon-carbon double bond within the molecule, and SiO ４／２ (B) an organopolysiloxane resin containing at least 20 mol% of the total siloxane units represented by (A), (C) a linear or branched organopolysiloxane having at least two curing-reactive functional groups containing carbon-carbon double bonds in the molecule and being liquid or plastic at 25°C, (D) an organopolysiloxane having curing-reactive functional groups at the molecular ends and containing more than 10% by mass of carbon-carbon double bonds in the molecule, (D) one or more curing agents necessary for curing the composition in an amount sufficient to cure the composition. A curable silicone composition comprising at least the following, wherein when the total sum of the entire composition excluding the solid filler and solvent is 100% by mass, the content of component (A) is in the range of 45 to 80% by mass, the content of component (B) is in the range of 20 to 55% by mass, the content of component (C) is in the range of 2 to 15% by mass, and the amount of curing-reactive functional groups containing carbon-carbon double bonds in 100 g of the composition excluding the solid filler and solvent is 2.0 mol% or more, and the cured product obtained by curing the composition exhibits a glass transition temperature between -30 and 120°C and a storage modulus of 0.5 MPa or more at 25°C.

2. The curable silicone composition according to claim 1, further characterized by containing (E) a functional inorganic filler.

3. The component (A) is an organopolysiloxane resin represented by the following average unit formula: (R ３ ３ SiO １／２ )(R ａ )(R ３ ２ SiO ２／２ )(R ｂ )(R ３ SiO ３／２ )(SiO ｃ )(R ４／２ )(R ｄ )(R ２ O １／２）ｅ (wherein each R ３ is independently a monovalent hydrocarbon group having 1 to 10 carbon atoms and not containing a carbon-carbon double bond; R ２ is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms; a, b, c, d, and e are numbers satisfying the following: 0.35 ≤ a ≤ 0.55, 0 ≤ b ≤ 0.20, 0 ≤ c ≤ 0.20, 0.30 ≤ d ≤ 0.65, 0 ≤ e ≤ 0.05, and a + b + c + d + e = 1). The curable silicone composition according to claim 1, characterized in that it is an organopolysiloxane resin represented by the above formula.

4. The above-mentioned component (B) is (B1) the following structural formula: R ４ ３ SiO(SiR) ４ ２ O) ｋ SiR ４ ３ (In the formula, each R ４ R is a monovalent hydrocarbon group having 1 to 10 carbon atoms independently, provided that R in one molecule ４ The curable silicone composition according to claim 1 or 2, wherein the linear diorganopolysiloxane is represented by (at least two of which are alkenyl groups, and k is a number from 400 to 10,000).

5. The above (C) component is (C1) with the following average unit formula: (R １ ３ SiO １／２ ) ａ´ (R ２ ２ SiO ２／２ ) ｂ´ (R ２ SiO ３／２ ) ｃ´ (SiO ４／２ ) ｄ´ (R ３ O １／２ ) ｅ´ (In the formula, each R １ R is a monovalent hydrocarbon group having 1 to 10 carbon atoms independently, provided that the total R in one molecule １ At least two of them are alkenyl groups, and each R ２ Each R is an independent monovalent hydrocarbon group having 1 to 10 carbon atoms and not containing an alkenyl group; ３ The curable silicone composition according to claim 1, characterized in that a is a branched organopolysiloxane represented by the following conditions: a', b', c', d', and e' are numbers satisfying the following conditions: 0.40 ≤ a' ≤ 0.80, 0 ≤ b' ≤ 0.90, 0 ≤ c' ≤ 0.60, 0 ≤ d' ≤ 0.50, 0 ≤ e' ≤ 0.05, where a' + b' + c' + d' = 1 and c' + d' ≥ 0.1).

6. The curable silicone composition according to claim 1, wherein component (D) is an organohydrogenpolysiloxane having at least two silicon-bonded hydrogen atoms in the molecule and a hydrosilylation reaction catalyst, and the organohydrogenpolysiloxane is contained in the composition in an amount that gives 0.9 to 2.0 moles of silicon-bonded hydrogen atoms per mole of total carbon-carbon double bonds in the composition.

7. A cured product obtained by curing the curable silicone composition according to any one of claims 1 to 6.

8. The cured product according to claim 7, characterized in that the elongation rate is 100% or more when a tensile test is performed as specified in JIS K 7161.

9. The cured product according to claim 7, characterized in that the loss tangent, which is the ratio of the storage modulus to the loss modulus at 25°C, is 0.3 or more.

10. A stress damping member comprising a cured product according to any one of claims 7 to 9.

11. A shock and vibration absorbing member comprising a cured product according to any one of claims 7 to 9.

12. A display component comprising a cured product according to any one of claims 7 to 9.

13. A semiconductor device comprising a cured product according to any one of claims 7 to 9.

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