Granular curable silicone composition, cured product of same, and method for producing same

Abstract

[Problem] To provide a curable silicone composition which is a composition that can contain large amounts of a functional inorganic filler, that exhibits an excellent hot meltability characterized by a high fluidity at high temperatures, an excellent gap-filling performance, and an excellent uniformity, and that yields a cured product, wherein this curable silicone composition can be favorably used in processes from sealing to molding, e.g., transfer molding, is resistant to dust generation, and exhibits an excellent handling workability; also, to provide a production method that exhibits an excellent production efficiency for and homogeneity of said composition. [Solution] The solution is a granular curable silicone composition and applications thereof, wherein the granular curable silicone composition comprises an organopolysiloxane resin (A) that contains at least 20 mol% or more T units, a curing agent (B), and a functional inorganic filler (C), with the component (C) content being 400-3,000 mass parts per 100 mass parts of the total of component (A) and component (B). This granular curable silicone composition is a solid at 25°C; has a melt viscosity, as measured with a flow tester at 180°C, of not more than 200 Pa·s; and has an average particle diameter in the range from 0.1-10.0 mm.

Description

Granular curable silicone composition, cured product thereof, and method for producing same

[0001] The present invention relates to a granular curable silicone composition that has hot-melt properties and high fluidity at high temperatures, and that gives a cured product with excellent gap-filling properties and uniformity. The present invention also relates to a cured product made from the granular curable silicone composition, a molding method for this cured product, and uses such as semiconductor devices that include this cured product. In this invention, the term "hot-melt properties" refers to the property of being solid at 25°C but exhibiting viscosity at 180°C.

[0002] Curable silicone compositions are used in a wide range of industrial fields because they cure to form cured products with excellent heat resistance, cold resistance, electrical insulation, weather resistance, water repellency, and transparency. Cured products of such curable silicone compositions are generally less susceptible to discoloration than other organic materials, and also suffer less deterioration in physical properties, making them suitable as sealants for optical materials and semiconductor devices. Meanwhile, in recent years, from the standpoint of ease of handling and workability, hot-melt curable silicone compositions have been widely used as sealants for optical materials and semiconductor devices.

[0003] In Patent Documents 1 and 2, the present applicant has proposed a hot-melt granular curable silicone composition for molding, primarily composed of a resinous silicone, which can be used for the above-mentioned applications. However, the granular compositions proposed in these inventions are fine granules with a particle size of 100 μm or less, and no granular composition that has been homogenized in advance by melt-kneading or the like is disclosed. For this reason, it is known that using the composition in its granular form poses a risk of generating dust and is difficult to handle. Furthermore, since the components of the granular silicone composition are mixed by mechanical force and are not a granular composition that is uniform and homogenized in composition, it is difficult to use in molding processes that do not involve material movement or shear pressure, such as compression molding or press molding. Therefore, the documents recommend transfer molding.

[0004] On the other hand, Patent Document 3 discloses a powder hot-melt composition using a resin-linear siloxane block copolymer, proposing particles having an average particle size of not more than 500 μm and flakes uniformly mixed using a twin-screw extruder with a toluene solvent or the like. However, while this document discloses that the composition may contain a reinforcing filler in a ratio of 0.1% to approximately 95%, the composition has a high melt viscosity, particularly at 180°C, and when a large amount of functional inorganic filler is added, the composition does not melt even when exposed to high temperatures, making it particularly unsuitable for transfer molding processes. In other words, Patent Document 3 does not disclose a hot-melt composition or granule thereof having a melt viscosity of 200 Pa·s or less at 180°C and containing a functional inorganic filler in an amount of more than 400 parts by mass per 100 parts by mass of the silicone component and curing agent combined.

[0005] Furthermore, these documents do not specifically disclose granular curable silicone compositions that contain a relatively large amount of inorganic filler, have good hot-melt properties, and have a relatively large average particle size that has been homogenized through a heat-melting process.

[0006] International Publication No. 2018 / 030288 Pamphlet International Publication No. 2018 / 235491 Pamphlet Special Publication No. 2016-522978

[0007] The object of the present invention is to provide a curable silicone composition that can contain large amounts of functional inorganic filler and that gives a cured product characterized by high fluidity at high temperatures and that has excellent hot-melt properties, gap-filling properties, and uniformity, and that is suitable for use in molding or sealing processes such as transfer molding, compression molding, and press molding, that generates little dust, and that is easy to handle, as well as a method for producing the same that is excellent in production efficiency and uniformity.Furthermore, the present invention provides a cured product obtained by curing the curable silicone composition, a semiconductor device component made of the cured product, a semiconductor device comprising the cured product, and a method for molding the cured product.

[0008] As a result of extensive investigation, the present inventors have found that (A) RSiO ３／２The inventors have discovered that the above-mentioned problems can be solved by a granular curable silicone composition comprising an organopolysiloxane resin containing siloxane units of the formula (wherein R is a monovalent hydrocarbon group) that account for at least 20 mol % of all siloxane units, (B) a curing agent, and (C) a functional inorganic filler, wherein the amount of component (C) is 400 to 3,000 parts by mass per 100 parts by mass of the combined total of components (A) and (B), the composition being solid at 25°C, having a melt viscosity of 200 Pa s or less at 180°C as measured with a flow tester, and having an average particle size in the range of 0.1 to 10.0 mm, and have completed the present invention.

[0009] The granular curable silicone composition is preferably formed into granules after being compositionally homogenized by melt-kneading in the temperature range of 50 to 150° C. Furthermore, the granular product of the present invention may be further molded into pellets or tablets.

[0010] The above problems are also solved by a cured product such as the granular molding, its use as a semiconductor device component, and a molding method for the cured product.

[0011] The granular curable silicone composition of the present invention has hot-melt properties, and even when it contains a large amount of functional inorganic filler, it has excellent melting and curing properties characterized by high fluidity at high temperatures; its dust-resistant granular form makes it easy to handle; and because the individual components are highly uniform, the cured product is characterized by high hardness and a low coefficient of linear expansion, making it particularly suitable for use as sealing, molding, and protective materials for semiconductor devices. Furthermore, the method for producing granular molded products of the present invention allows for efficient production using only a simple mixing step, and the method for molding cured products using the granular molded products of the present invention allows for the efficient production of semiconductor device components made from the cured product, as well as semiconductor devices containing the cured product.

[0012] 1A and 1B are diagrams showing the granular curable silicone composition obtained in Production Example 1 (Comparative Example 1) and Example 1, respectively, crushed in a hot press before being melt-kneaded.

[0013] [Granular Form] The curable silicone composition of the present invention is characterized by its hot-melt properties, which are characterized by its compositional features and specific melting characteristics, and is also characterized by its granular form. Here, "granular" means that the components that make up the composition are at least substantially homogenized and in the form of granules with a certain average particle size. The problems of the present invention may not be solved by granular mixtures in which the components are simply mixed using mechanical force, or by compositions that have not been granulated for the purpose of compositional homogenization. Here, in the granular composition of the present invention, "average particle size" refers to the average primary particle size of granules made from the homogenized composition, unless otherwise defined.

[0014] The granular molded product of the present invention has an average particle size in the range of 0.1 to 10.0 mm, preferably in the range of 0.1 to 5.0 mm, more preferably in the range of 0.5 to 5.0 mm, and particularly preferably in the range of 1.0 to 5.0 mm. As long as it is in the form of granules, the shape is not particularly limited, and may be irregular granules obtained by pulverization or granular molded products formed into spherical, cylindrical, spindle-shaped, plate-shaped, irregular shapes, etc. The shapes of these granules can be easily observed using an optical microscope, etc.

[0015] In particular, the granular composition according to the present invention preferably has a particle size distribution in which 85% by mass or more of the constituent particles are within the range of 0.1 to 10 mm, more preferably within the range of 0.1 to 5 mm, and does not contain a large amount of fine particles or coarse particles outside this range. Here, if the granular composition according to the present invention has an average particle size outside the above-mentioned range, or if the number of particles outside the upper and lower particle size limits in the particle size distribution is greater than the above-mentioned range, the substrate tends not to be sealed properly during the molding step.

[0016] For example, if there is too much composition in the granular composition with a particle size smaller than the above range, the small particle size composition will melt preferentially, and will not melt uniformly during heat compression, which will tend to prevent the substrate from being properly sealed. Also, if there is too much composition with a particle size larger than the above range, the small particle size composition will be less likely to melt, and some of the granular resin composition will remain unmelted in the molten composition during heat compression, which may prevent the substrate from being properly sealed. The particle size distribution of the granular resin composition can be measured using a general particle size analyzer. Since the granular composition of the present invention has a relatively large average particle size, the granular composition may be sieved through sieves with various mesh sizes stacked from bottom to top in order of smallest mesh size, and the mass of the particles remaining on each sieve may be calculated.

[0017] [Melt Viscosity of Granular Composition] The granular curable silicone composition of the present invention is either non-fluid or a plastic solid at 25°C, but exhibits high fluidity at high temperatures. Specifically, the granular composition has a melt viscosity of 200 Pa·s or less, more preferably 150 Pa·s or less, and particularly preferably 100 Pa·s or less, as measured with a flow tester at 180°C. It may be, and is preferred, a granular molded product that satisfies the compositional characteristics described below and has a melt viscosity in the range of 1 to 100 Pa·s, or 1 to 50 Pa·s. Note that the configuration of the invention described in Patent Document 3, etc., fails to achieve high fluidity characterized by a melt viscosity of 200 Pa·s or less at 180°C, particularly when the content of component (C) is high, and this can result in insufficient gap-filling properties of the composition and insufficient physical properties of the cured product.

[0018] [Curable Silicone Composition] The granular curable silicone composition of the present invention comprises: (A) RSiO ３／２ (wherein R is a monovalent hydrocarbon group), at least 20 mol % of all siloxane units are siloxane units; (B) a curing agent; and (C) a functional inorganic filler. The composition is characterized in that the content of component (C) is 400 to 3,000 parts by mass per 100 parts by mass of the total of components (A) and (B), and other optional components may be included as long as the above-mentioned conditions of form and melt viscosity are met.

[0019] Component (A) is the main component of the composition and is RSiO ３／２ The organopolysiloxane resin preferably contains siloxane units represented by the formula (wherein R is a monovalent hydrocarbon group) in an amount of at least 20 mol % of all siloxane units, and is an organopolysiloxane resin component that itself has hot-melt properties in order to impart hot-melt properties to the composition. Furthermore, it preferably contains reactive functional groups in order to react with component (B) described below to form a cured product. Examples of curing reactions include hydrosilylation reactions, radical reactions, and condensation reactions, but from the perspective of the curing rate of the resulting composition, it is preferable that the reaction be either a hydrosilylation reaction, a radical reaction, or both.

[0020] Component (A) preferably has a reactive functional group, such as a hydrosilylation-reactive group or a radical-reactive group. Examples of hydrosilylation-reactive groups include alkenyl groups having 2 to 20 carbon atoms, such as vinyl, allyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, undecenyl, and dodecenyl, as well as silicon-bonded hydrogen atoms. The hydrosilylation-reactive group is preferably an alkenyl group. This alkenyl group may be linear or branched, and is preferably a vinyl group or a hexenyl group. Component (A) preferably has at least two hydrosilylation-reactive groups per molecule.

[0021] Examples of groups bonded to silicon atoms in component (A) other than hydrosilylation reactive groups include alkyl groups having 1 to 20 carbon atoms such as methyl groups, halogen-substituted alkyl groups having 1 to 20 carbon atoms, aryl groups having 6 to 20 carbon atoms such as phenyl groups, halogen-substituted aryl groups having 6 to 20 carbon atoms, aralkyl groups having 7 to 20 carbon atoms, alkoxy groups, and hydroxyl groups. Methyl groups, phenyl groups, and hydroxyl groups are particularly preferred.

[0022] Examples of radically reactive groups in component (A) include alkyl groups having 1 to 20 carbon atoms, such as methyl groups; alkenyl groups having 2 to 20 carbon atoms, such as vinyl groups and hexenyl groups; acrylic-containing groups, such as 3-acryloxypropyl groups and 4-acryloxybutyl groups; methacrylic-containing groups, such as 3-methacryloxypropyl groups and 4-methacryloxybutyl groups; and silicon-bonded hydrogen atoms. Alkenyl groups are preferred as this radically reactive group. These alkenyl groups may be linear or branched, and are preferably vinyl or hexenyl groups. It is preferred that component (A) have at least two radically reactive groups per molecule.

[0023] Examples of groups bonded to silicon atoms in component (A) other than radical reactive groups include halogen-substituted alkyl groups having 1 to 20 carbon atoms, aryl groups having 6 to 20 carbon atoms, halogen-substituted aryl groups having 6 to 20 carbon atoms, aralkyl groups having 7 to 20 carbon atoms, alkoxy groups, and hydroxyl groups, including the same groups as those listed above. Phenyl groups and hydroxyl groups are particularly preferred. It is particularly preferred that component (A) have aryl groups, especially phenyl groups, accounting for 10 mol % or more of all organic groups in the molecule.

[0024] [Component (A1)] More specifically, at least a part or all of component (A) is a curable composition having a softening point of 30°C or higher, a curable functional group containing at least one carbon-carbon double bond in the molecule, and RSiO ３／２ Preferably, the resin is a hot-melt organopolysiloxane resin containing siloxane units represented by the formula (wherein R is a monovalent hydrocarbon group) in an amount of at least 20 mol % of all siloxane units. These components will be described below.

[0025] Component (A1) itself has hot-melt properties and contains a curable functional group containing at least one carbon-carbon double bond in the molecule, and therefore is cured by the curing agent (B), which will be described later. Component (A1) is preferably a resinous organopolysiloxane.

[0026] The component (A1) is particularly a resinous organopolysiloxane having a carbon-carbon double bond group (a hydrosilylation reactive group and / or a radical reactive group), and is represented by RSiO ３／２ (wherein R is a monovalent hydrocarbon group), at least 20 mol % of all siloxane units are siloxane units, and (A1-1) 10 mol % or more of the silicon-bonded organic groups are aryl groups.

[0027] Suitable examples of such component (A1) include MT resins, MDT resins, MTQ resins, MDTQ resins, TD resins, TQ resins, and TDQ resins, which are composed of any combination of triorganosiloxy units (M units) (organo groups are methyl groups only, or methyl groups and vinyl groups or phenyl groups), diorganosiloxy units (D units) (organo groups are methyl groups only, or methyl groups and vinyl groups or phenyl groups), monoorganosiloxy units (T units) (organo groups are methyl groups, vinyl groups, or phenyl groups), and siloxy units (Q units), with the content of T units being at least 20 mol% or more of the total siloxane units. １ Preferably, the ) component has at least two carbon-carbon double bond groups (hydrosilylation reactive groups and / or radical reactive groups) in the molecule, and 10 mol % or more of all silicon-bonded organic groups in the molecule are aryl groups, particularly phenyl groups.

[0028] Preferably, the component (A1) is the following (R １ ３ SiO １／２ ) ａ (R ２ ２ SiO ２／２ ) ｂ (R ３ SiO ３／２ ) ｃ (SiO ４／２ ) ｄ (R ４ O １／２）ｅ It is an organopolysiloxane that is solid at room temperature but softens as the temperature rises, exhibiting hot-melt properties.

[0029] In the formula, each R１ , R ２ , R ３ are independently monovalent hydrocarbon groups having 1 to 10 carbon atoms, provided that at least two of all R groups in one molecule must be alkenyl groups, and 70% or more of all alkenyl groups must be R １ It is preferable that R ４ is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms; and a, b, c, d, and e are numbers that satisfy the following: (0.10≦a≦0.40, 0≦b≦0.50, 0.20≦c≦0.90, 0≦d≦0.20, 0≦e≦0.05, with the proviso that a+b+c+d=1).

[0030] The preferred alkenyl group content is 10 to 20 mol% of the total R component. Below this range, a cured product exhibiting sufficient strength cannot be obtained, while above this range, the cured product tends to be hard and brittle. Examples of alkenyl groups include vinyl, allyl, butenyl, pentenyl, and hexenyl groups. From the viewpoint of imparting suitable hot-melt properties to this component, R １ , R ２ , R ３ At least a part of the groups is preferably an aryl group, more preferably a phenyl group. Examples of other monovalent hydrocarbon groups include a methyl group.

[0031] Furthermore, in the formula, a represents a group represented by the general formula: R １ ３ SiO １ / ２ is a number that indicates the proportion of siloxane units represented by the formula: R ２ ２ SiO ２ / ２ and is a number that satisfies the relationship 0≦b≦0.5. This is because good hot melt properties can be obtained when b is equal to or less than the upper limit of the above range. Furthermore, c is a number that indicates the proportion of siloxane units represented by the general formula: R ３ SiO ３ / ２is a number that indicates the proportion of siloxane units represented by the general formula: SiO ４ / ２ is a number that indicates the proportion of siloxane units represented by the formula: R, and is a number that satisfies 0≦d≦0.20, preferably 0≦d≦0.10. This is because when d is equal to or less than the upper limit of the above range, the mechanical strength of the resulting cured product is good. ２ O １ / ２ is a number indicating the proportion of units represented by the formula a, b, c, and d, and satisfies the condition 0≦e≦0.05. This is because when e is equal to or less than the upper limit of the above range, the hardness of the resulting cured product at room temperature is good. In the formula, the sum of a, b, c, and d is 1.

[0032] Component (A1) exhibits hot-melt properties; specifically, it is non-flowable at 25°C, and has a melt viscosity at 150°C of 8000 Pa s or less, preferably 5000 Pa s or less, and more preferably in the range of 10 to 3000 Pa s. "Non-flowable" means that it does not flow under no load, and refers to a state below the softening point measured by the ring and ball softening point test method for hot-melt adhesives specified in JIS K 6863-1994 "Softening Point Test Method for Hot-Melt Adhesives." In other words, in order to be non-flowable at 25°C, the softening point must be higher than 25°C.

[0033] Component (A), preferably component (A1), may be an organosiloxane resin of any molecular weight as long as it exhibits the structure and melting properties described above. For example, an organopolysiloxane having the structure described above may be used in which some of the alkenyl groups have been crosslinked with component (B), described below, to increase the molecular weight. However, from the viewpoint of the melting properties of the resulting composition, the molecular weight (Mw) is preferably 20,000 g / mol or less.

[0034] Furthermore, as mentioned above, component (A) is a solid at room temperature. Therefore, from the viewpoint of ease of handling when mixed with other components, it is preferable to make it a particulate resin or to dissolve it in other components required for the present composition and use it as a liquid mixture.

[0035] When component (A) is used in the form of fine particles, the particle size is not limited, but the average primary particle size is preferably within the range of 1 to 5,000 μm, 1 to 500 μm, 1 to 100 μm, 1 to 20 μm, or 1 to 10 μm. This average primary particle size can be determined, for example, by observation with an optical microscope or SEM. The shape of the fine particle (A) component is not limited, and examples include spherical, spindle-shaped, plate-shaped, needle-shaped, and irregular shapes. Spherical or true spherical shapes are preferred because they melt uniformly. In particular, by forming component (A) into true spherical fine particles, the process of producing the present composition by powder mixing or melt-kneading, as described below, can be carried out efficiently.

[0036] When component (A) is microparticulated, the production method is not limited, and known methods can be used. When obtaining microparticulate component (A), a hydrosilylation reaction catalyst, which is component (B) described below, may also be microparticulated together with component (A), and this is preferred.

[0037] Specific methods for microparticulating component (A) include pulverizing component (A), which is solid at room temperature, using a pulverizer, and directly microparticulating component (A) in the presence of a solvent. The pulverizer is not limited, and examples include a roll mill, a ball mill, a jet mill, a turbo mill, and a planetary mill. Alternatively, component (A) may be directly microparticulated in the presence of a solvent, for example, by spraying with a spray dryer, or by microparticulation with a twin-screw kneader or belt dryer. When microparticulating component (A), it is preferable to obtain spherical hot-melt organopolysiloxane resin microparticles by spraying with a spray dryer.

[0038] By using a spray dryer or the like, it is possible to produce component (A) that is spherical and has an average primary particle size of 1 to 500 μm. The heating and drying temperature of the spray dryer must be appropriately set based on the heat resistance, etc., of the organopolysiloxane resin microparticles. In order to prevent secondary aggregation of the organopolysiloxane resin microparticles, it is preferable to control the temperature of the organopolysiloxane resin microparticles below their glass transition temperature. The organopolysiloxane resin microparticles obtained in this manner can be recovered using a cyclone, bag filter, or the like.

[0039] To obtain a uniform component (A), a solvent may be used in the above step as long as it does not inhibit the curing reaction. The solvent is not limited, but examples include aliphatic hydrocarbons such as n-hexane, cyclohexane, and n-heptane; aromatic hydrocarbons such as toluene, xylene, and mesitylene; ethers such as tetrahydrofuran and dipropyl ether; silicones such as hexamethyldisiloxane, octamethyltrisiloxane, and decamethyltetrasiloxane; esters such as ethyl acetate, butyl acetate, and propylene glycol monomethyl ether acetate; and ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone.

[0040] Furthermore, when a silicone compound that is liquid at room temperature is used as all or part of the component (B) described below, the component (A) may be dissolved in part of the component (B). The liquid silicone compound exhibits a certain degree of mutual solubility with the component (A), and the component (A) can be dissolved by adding, for example, 10 to 50 parts by mass of a part of the component (B) per 100 parts by mass of the component (A). By liquefying the component (A), it is possible to efficiently produce the present composition described below by powder mixing or melt kneading.

[0041] [Component (B)] Component (B) is a curing agent for curing component (A), and is not limited as long as it can cure component (A). When component (A) has an alkenyl group, component (B) is an organohydrogenpolysiloxane having at least two silicon-bonded hydrogen atoms per molecule and a hydrosilylation catalyst. When component (A) contains an alkenyl group and a hydrosilylation catalyst, component (B) may be an organopolysiloxane having at least two silicon-bonded hydrogen atoms per molecule alone, or may be used in combination with a hydrosilylation catalyst. Furthermore, when component (A) has an alkenyl group, component (B) may be an organic peroxide, or may be used in combination with an organopolysiloxane having at least two silicon-bonded hydrogen atoms per molecule. On the other hand, when component (A) has silicon-bonded hydrogen atoms, component (B) is an organopolysiloxane having at least two alkenyl groups per molecule and a hydrosilylation catalyst; when component (A) has silicon-bonded hydrogen atoms and contains a hydrosilylation catalyst, component (B) may be an organopolysiloxane having at least two alkenyl groups per molecule alone, but a hydrosilylation catalyst may also be used in combination. Furthermore, when component (A) has reactive silanol groups, a condensation catalyst may also be contained. Note that when a condensation reaction is used as the curing reaction, a known thermal base generator or the like may be used as part of component (B).

[0042] As mentioned above, component (B) contains a curing catalyst suited to the selected reaction system, and the granular composition of the present invention is preferably granulated after being homogenized by melt kneading or the like in a temperature range of 50 to 150°C, preferably 50 to 120°C, for the purpose of achieving compositional uniformity. Therefore, from the standpoint of suppressing unintended curing reactions and maintaining the curing reactivity of the granular curable silicone composition of the present invention, component (B) is preferably a curing agent that is inactive unless subjected to a certain level of thermal energy stimulation; specifically, a curing agent that is insoluble in the other components of the composition at room temperature (i.e., incompatible with them) and contains a curing reaction catalyst that becomes active in the composition when stimulated by thermal energy of 80°C or higher, preferably 100°C or higher, and more preferably 120°C or higher, and below which the curing reaction does not begin. For example, it is possible to dissolve some or all of the curing agent in advance in other components, including component (A), and then incorporate the curing agent into the present composition. However, such a curing agent dissolves in the other components at room temperature and diffuses throughout the system, which can lead to the curing reaction proceeding at an unintended time, and the storage stability and controllability of the curing reactivity of the composition as a whole may be poor.

[0043] More specifically, component (B) preferably contains or is one or more curing agents selected from (B1) an organic peroxide having a 10-hour half-life at a temperature of 80° C. or higher, and (B2) hydrosilylation reaction catalyst-containing thermoplastic resin microparticles containing a thermoplastic resin having a softening point or glass transition point of 80° C. or higher. This is because the use of component (B1) or (B2) as a curing agent effectively suppresses unintended curing reactions, even when the composition is homogenized and granulated by a process involving heating, such as melt-kneading, and the resulting granular composition can achieve both good hot-melt properties and high-temperature curing properties.

[0044] Component (B1) is a curing agent that is preferably used when a radical reaction is used as the curing reaction for the present composition, and is preferably an organic peroxide that has a 10-hour half-life 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.

[0045] There are no limitations on the amount of organic peroxide contained, but it is preferable that the amount be in the range of 0.05 to 10 parts by mass, or 0.10 to 5.0 parts by mass, per 100 parts by mass of component (A).

[0046] Component (B2) is a part of the curing agent suitable for use when a hydrosilylation reaction is used as the curing reaction for the present composition, and may be either fine particles in which a platinum-based catalyst is dissolved or dispersed in a thermoplastic resin, or microcapsule fine particles in which a platinum-based catalyst is contained as a core within a thermoplastic resin shell. Examples of platinum-based catalysts include platinum black, platinum-supported carbon fine powder, platinum-supported silica fine powder, chloroplatinic acid, alcohol-modified chloroplatinic acid, platinum olefin complexes, and platinum alkenylsiloxane complexes. The thermoplastic resin used in component (B2) is not particularly limited as long as it is substantially impermeable to the platinum-based catalyst at least during production and storage of the present composition and is substantially soluble in the organopolysiloxane, the main component of the present composition. However, the softening point or glass transition point of this thermoplastic resin is preferably 80°C or higher, more preferably 120°C or higher. Specifically, silicone resins, polysilane resins, epoxy resins, acrylic resins, methylcellulose resins, and polycarbonate resins are suitable, but they must have low solubility in the present composition. The softening point is the temperature at which the resin begins to flow under its own weight or surface tension, and can be measured by observing pulverized particles under a microscope while increasing the temperature at a constant rate. The glass transition point can also be measured using a differential scanning calorimeter (DSC). In the present invention, it is preferable that either the softening point or the glass transition point is 120°C or higher. This is because if the softening point or glass transition point of the thermoplastic resin is below 120°C, there is a risk that the platinum component will begin to leach out during the process of homogenizing the present composition, as described below. The average particle size of the platinum-based catalyst-containing thermoplastic microparticles is not limited, but is preferably within the range of 0.1 to 500 μm, and more preferably within the range of 0.3 to 100 μm. This is because it is difficult to prepare platinum-based catalyst-containing thermoplastic resin microparticles with an average particle size below the lower limit of the above range, while if the average particle size exceeds the upper limit of the above range, dispersibility in the curable silicone resin composition decreases.

[0047] The method for preparing such platinum-based catalyst-containing thermoplastic resin microparticles is not limited, and examples include conventionally known chemical methods such as interfacial polymerization and in-situ polymerization, as well as physical and mechanical methods such as coacervation and submerged drying. Submerged drying and vapor-phase drying are particularly desirable because they allow for the relatively easy production of microcapsule microparticles with a narrow particle size distribution. While the microparticles obtained by these methods can be used as is, it is desirable to wash them with an appropriate cleaning solvent to remove the platinum-based catalyst adhering to their surface in order to obtain a curable silicone resin composition with excellent storage stability. A suitable cleaning solvent is one that does not dissolve the thermoplastic resin but dissolves the platinum-based catalyst. Examples of such cleaning solvents include alcohols such as methyl alcohol and ethyl alcohol, and low-molecular-weight organopolysiloxanes such as hexamethyldisiloxane. The ratio of the hydrosilylation catalyst to the thermoplastic resin varies significantly depending on the method for producing the granules, so no particular limitation can be placed on it. However, it is preferable for the platinum-based catalyst content to be 0.01% by mass or greater relative to the thermoplastic resin. This is because if the platinum catalyst content is less than 0.01% by mass, the physical properties of the cured product will be impaired unless the composition contains a large amount of platinum catalyst-containing thermoplastic resin particles.

[0048] The amount of the hydrosilylation catalyst added is preferably an amount that provides a metal atom concentration, by mass, of 0.01 to 500 ppm, 0.01 to 100 ppm, or 0.01 to 50 ppm, relative to the entire composition.

[0049] When a hydrosilylation reaction is used as the curing reaction for the present composition, component (B) may contain, in addition to a hydrosilylation reaction catalyst (preferably the aforementioned component (B2)), an organosiloxane component other than component (A) as a hydrosilylation crosslinking component, and preferably contains (B3) an organohydrogenpolysiloxane. The structure is not particularly limited and may be linear, branched, cyclic, or resinous, but from the viewpoint of excellent curing properties of the resulting composition, it is preferable to use an organohydrogenpolysiloxane having HR at the terminal. ２ SiO １／２Hydrogen diorganosiloxy units (M Ｈ Preferably, the organohydrogenpolysiloxane has a unit (R) independently representing a monovalent organic group.

[0050] More specifically, the organohydrogenpolysiloxane (B3) serving as the hydrosilylation cross-linking component is preferably an organopolysiloxane in which 20 to 70 mol % of all silicon-bonded organic groups are phenyl groups. This is because when the phenyl group content is at least the lower limit of the above range, the resulting cured product has good mechanical strength at high temperatures, while when it is at most the upper limit of the above range, the resulting cured product has good mechanical strength.

[0051] Component (B3) contains two or more silicon-bonded hydrogen atoms per molecule, providing sufficient crosslinking reactivity for curing and resulting in a cured product with good hardness. Examples of silicon-bonded organic groups in component (B) include alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, cyclopentyl, cyclohexyl, and cycloheptyl; aryl groups such as phenyl, tolyl, and xylyl; and aralkyl groups such as benzyl and phenethyl. Preferred are phenyl and alkyl groups having 1 to 6 carbon atoms.

[0052] Examples of such a component (B3) include: (B3-1) a compound represented by the general formula: HR ４ ２ SiO(R ４ ２ SiO) ｎ SI ４ ２ and (B3-2) a linear organopolysiloxane represented by the average unit formula: (R ４ SiO ３／２ ) ｐ (R ４ ２ SiO ２／２ ) ｑ (HR ４ ２ SiO １／２ ) ｒ (SiO ４／２ ) ｓ (XO１／２ ) ｔ It is preferable to use a combination of these two types of component (B3) as the hydrosilylation crosslinking component.

[0053] In the formula, R ４ are the same or different and are phenyl groups or alkyl groups having 1 to 6 carbon atoms. ４ Examples of the alkyl group of R include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a cyclopentyl group, and a cyclohexyl group. ４ The content of phenyl groups is in the range of 30 to 70 mol %.

[0054] In the formula, n is an integer in the range of 5 to 1,000. In the formula, p is a positive number, q is 0 or a positive number, r is a positive number, s is 0 or a positive number, t is 0 or a positive number, q / p is a number in the range of 0 to 10, r / p is a number in the range of 0.1 to 5, s / (p+q+r+s) is a number in the range of 0 to 0.3, and t / (p+q+r+s) is a number in the range of 0 to 0.4.

[0055] In such a case, it is preferable to use a combination of components (B3-1) and (B3-2) in the (B3) component, from the viewpoint of facilitating control of the curing rate of the composition and the crosslink density of the resulting cured product. The ratio of the two components, per alkenyl group in the entire composition, is preferably (B3-1):(B3-2)=0.05-0.6:0.4-0.95, more preferably 0.05-0.5:0.5-0.95, and even more preferably 0.05-0.4:0.5-0.95.

[0056] When the above-mentioned organohydrogenpolysiloxane is used as part of component (B), there are no restrictions on its content, but in order to cure the composition, it is preferable that the amount be in the range of 0.5 to 20 moles, or 1.0 to 10 moles, of silicon-bonded hydrogen atoms per mole of alkenyl groups in the composition. The amount of hydrosilylation reaction catalyst used is as described above.

[0057] In the composition of the present invention, a particularly suitable component (B) is one that contains the above-mentioned components (B2), (B3-1), and (B3-2). As a result, the composition as a whole effectively suppresses side reactions and unintended curing reactions, and has the advantages of excellent hot-melt properties and heat-curing properties at high temperatures.

[0058] [Component (C)] Component (C) of the present invention is an inorganic filler, and can provide a curable silicone composition that cures to give a cured product with excellent hardness and toughness at room temperature to high temperatures. In the present invention, even when component (C) is added in a range of 400 to 3,000 parts by mass per 100 parts by mass of the total of components (A) and (B), a low melt viscosity suitable for encapsulation, transfer molding, compression molding, and press molding can be achieved, and component (C) can be blended in a range of 500 to 3,000 parts by mass, or in a range of 800 to 3,000 parts by mass.

[0059] In order to achieve a low average coefficient of linear expansion for the cured product of the granular curable silicone composition of the present invention, the content of component (C) is preferably at least 50% by volume of the total composition, more preferably at least 60% by volume, even more preferably at least 70% by volume, and especially preferably in the range of 80 to 95% by volume.

[0060] In order to achieve the above blending amounts and a low average linear expansion coefficient for the resulting cured product, it is preferable that component (C) be treated with a specific surface treatment agent, particularly a surface treatment agent in an amount of 0.1 to 2.0 mass%, 0.1 to 1.0 mass%, or 0.2 to 0.8 mass%, relative to the total mass of component (C). Treating component (C) with the above treatment amount of surface treatment agent has the advantage of allowing a high volume percentage of component (C) to be stably blended into the composition. Furthermore, any surface treatment method can be used, and any desired method can be used, such as a homogeneous mixing method using mechanical force (dry method) or a wet mixing method using a solvent.

[0061] Examples of these surface treatment agents include fluorine compounds such as methylhydrogenpolysiloxane, silicone resin, metal soap, silane coupling agent, perfluoroalkylsilane, and perfluoroalkyl phosphate ester salt, among others. Silicone-based surface treatment agents are particularly preferred, as described below. When a silane-based surface treatment agent such as methyltrimethoxysilane or phenyltrimethoxysilane is selected as the surface treatment agent, the hot-melt properties of the entire composition may be impaired, and the component (C) may not be stably blended up to the volume percent content described above. When an alkyltrialkoxysilane having a long-chain alkyl group such as an octyl group is selected as the surface treatment agent, the hot-melt properties of the composition and the blending stability of the component (C) tend to be maintained, but the strength of the cured product obtained by curing the composition of the present invention may be reduced, which may result in cracking or molding defects.

[0062] Here, examples of the organosilicon compound that is the surface treatment agent include low molecular weight organosilicon compounds such as silane, silazane, siloxane, or the like, and organosilicon polymers or oligomers such as polysiloxane, polycarbosiloxane, or the like.Preferred examples of silanes are so-called silane coupling agents.Representative examples of such silane coupling agents include alkyltrialkoxysilanes (methyltrimethoxysilane, vinyltrimethoxysilane, hexyltrimethoxysilane, octyltrimethoxysilane, decyltrimethoxysilane, or the like), and organofunctional group-containing trialkoxysilanes (glycidoxypropyltrimethoxysilane, epoxycyclohexylethyltrimethoxysilane, methacryloxypropyltrimethoxysilane, aminopropyltrimethoxysilane, or the like). Preferred siloxanes and polysiloxanes include hexamethyldisiloxane, 1,3-dihexyl-tetramethyldisiloxane, trialkoxysilyl single-terminated polydimethylsiloxane, trialkoxysilyl single-terminated dimethylvinyl single-terminated polydimethylsiloxane, trialkoxysilyl single-terminated organofunctional group single-terminated polydimethylsiloxane, trialkoxysilyl doubly-terminated polydimethylsiloxane, organofunctional group doubly-terminated polydimethylsiloxane, or the like. When siloxanes are used, the number n of siloxane bonds preferably ranges from 2 to 150. Examples of preferred silazanes include hexamethyldisilazane, 1,3-dihexyl-tetramethyldisilazane, or the like. Examples of preferred polycarbosiloxanes are polymers having Si-C-C-Si bonds within the polymer backbone.

[0063] Particularly preferred examples of silicone-based surface treatment agents include silicone-based surface treatment agents having at least one polysiloxane structure and a hydrolyzable silyl group in the molecule. Most preferred is the use of a silicone-based surface treatment agent having at least one polysiloxane structure and a hydrolyzable silyl group in the molecule, represented by the structural formula (1): R' ｎ (RO) ３－ｎ SiO—(R′ ２SiO) ｍ -SiR' ｎ (RO) ３－ｎ or structural formula (2): R' ３ SiO—(R′ ２ SiO) ｍ -SiR' ｎ (RO) ３－ｎ Examples include organopolysiloxanes having a linear alkoxysilyl end group represented by the formula: In this formula, R is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms (= methyl, ethyl, or propyl), and each R' is independently an alkyl group having 1 to 20 carbon atoms, a halogen-substituted alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, a halogen-substituted aryl group having 6 to 20 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms, examples of which are the same as those described above. n is a number ranging from 0 to 2, and m is a number ranging from 2 to 200, and may also be a number ranging from 2 to 150.

[0064] Component (C) is preferably at least one filler that has no softening point or does not soften below the softening point of component (A). It may also be a component that improves the handling and workability of the composition and imparts mechanical and other properties to the cured product of the composition. Examples of component (C) include inorganic fillers, organic fillers, and mixtures thereof, with inorganic fillers being preferred. Examples of inorganic fillers include reinforcing fillers, white pigments, thermally conductive fillers, electrically conductive fillers, phosphors, and mixtures of at least two of these. To achieve a high volumetric loading, it is preferable that 40% or more of the total component (C) contains reinforcing fillers with an average particle size of 10.0 μm or more. 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, flat, acicular, plate-like, amorphous, etc.

[0065] When the present composition is used as a sealant, protective agent, adhesive, light reflector, or the like, it is preferable to incorporate a reinforcing filler as component (E) to impart mechanical strength to the cured product and improve protective or adhesive properties. Examples of 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, zinc carbonate, glass beads, glass powder, talc, clay, mica, kaolin, silicon carbide, silicon nitride, aluminum nitride, carbon black, graphite, titanium dioxide, calcium sulfate, barium carbonate, magnesium carbonate, magnesium sulfate, barium sulfate, cellulose, and aramid. Furthermore, these reinforcing fillers may be surface-treated with an organoalkoxysilane such as methyltrimethoxysilane; an organohalosilane such as trimethylchlorosilane; an organosilazane such as hexamethyldisilazane; or a siloxane oligomer such as an α,ω-silanol group-blocked dimethylsiloxane oligomer, an α,ω-silanol group-blocked methylphenylsiloxane oligomer, or an α,ω-silanol group-blocked methylvinylsiloxane oligomer. 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 fiber, calcium carbonate whiskers, titanium oxide whiskers, and ceramic fiber; and fibrous fillers such as aramid fiber, polyimide fiber, and polyparaphenylene benzobisoxazole fiber may be used.Furthermore, plate-like fillers or granular fillers such as talc, kaolin clay, calcium carbonate, zinc oxide, calcium silicate hydrate, mica, glass flakes, glass powder, magnesium carbonate, silica, titanium oxide, 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, and pulverized products of the above-mentioned fibrous fillers may also be used.

[0066] In particular, from the standpoint of imparting hardness to the cured product of the present composition at room temperature to high temperatures, it is preferred that component (C) be spherical silica or aluminum oxide (alumina) having an average particle size of 10.0 μm or more.

[0067] Component (C) may contain silicone microparticles that do not have hot-melt properties, which can improve or, if desired, adjust stress relaxation properties, etc. Examples of silicone microparticles include non-reactive silicone resin microparticles and silicone elastomer microparticles, with silicone elastomer microparticles being a preferred example from the standpoint of improving flexibility or stress relaxation properties.

[0068] Silicone elastomer microparticles are crosslinked products of linear diorganopolysiloxanes primarily composed of diorganosiloxy units (D units). Silicone elastomer microparticles can be prepared by crosslinking diorganopolysiloxanes through hydrosilylation reactions or silanol group condensation reactions. Among these, they are preferably obtained by crosslinking an organohydrogenpolysiloxane having silicon-bonded hydrogen atoms in the side chain or at the end with a diorganopolysiloxane having unsaturated hydrocarbon groups such as alkenyl groups in the side chain or at the end in the presence of a hydrosilylation catalyst. Silicone elastomer microparticles can take various shapes, such as spherical, flat, and irregular, but spherical is preferred from the standpoint of dispersibility, and true spheres are even more preferred. Examples of commercially available silicone elastomer microparticles (C) include the "Trefil E Series" and "EP Powder Series" manufactured by Dow Corning Toray Co., Ltd., and the "KMP Series" manufactured by Shin-Etsu Chemical Co., Ltd. The silicone elastomer particles may be surface-treated. The elastomer particles may be made of acrylonitrile butadiene rubber, isoprene, styrene butadiene rubber, ethylene propylene rubber, or the like.

[0069] Furthermore, when the present composition is used as a wavelength conversion material for LEDs, a phosphor may be blended as component (C) to convert the wavelength of light emitted from an optical semiconductor element. The phosphor is not particularly limited, and examples thereof include yellow-, red-, green-, and blue-emitting phosphors composed of oxide-based phosphors, oxynitride-based phosphors, nitride-based phosphors, sulfide-based phosphors, oxysulfide-based phosphors, and the like, which are widely used in light-emitting diodes (LEDs). Examples of oxide-based phosphors include yttrium-, aluminum-, and garnet-based YAG-based green- to yellow-emitting phosphors containing cerium ions; terbium-, aluminum-, and garnet-based TAG-based yellow-emitting phosphors containing cerium ions; and silicate-based green- to yellow-emitting phosphors containing cerium and / or europium ions. Examples of oxynitride-based phosphors include silicon-, aluminum-, oxygen-, and nitrogen-based sialon-based red- to green-emitting phosphors containing europium ions. Examples of nitride-based phosphors include calcium, strontium, aluminum, silicon, and nitrogen-based red-emitting phosphors containing europium ions. Examples of sulfide-based phosphors include ZnS-based green-emitting phosphors containing copper ions or aluminum ions. Examples of oxysulfide-based phosphors include YS-based phosphors containing europium ions. ２ O ２ S-based red-emitting phosphors are exemplified. In the present composition, two or more of these phosphors may be used in combination.

[0070] Furthermore, the present composition may contain a thermally conductive filler or an electrically conductive filler to impart thermal conductivity or electrical conductivity to the cured product. Examples of such thermally conductive fillers or electrically conductive fillers include fine metal powders such as gold, silver, nickel, copper, aluminum, tin, lead, zinc, bismuth, and antimony; fine powders obtained by vapor-depositing or plating metals such as gold, silver, nickel, and copper on the surface of fine powders such as ceramic, glass, quartz, and organic resin; 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 present composition, metal oxide powders or metal nitride powders are preferred, and aluminum oxide powder, zinc oxide powder, and aluminum nitride powder are particularly preferred.

[0071] Furthermore, the composition may contain a colorant to impart color to the cured product. Examples of such colorants include black titanium oxide, pitch (the residue obtained by distilling tar obtained by dry distillation of organic substances such as petroleum, coal, and wood), carbon black, acetylene black, and red iron oxide. Acetylene black is preferably used when the content of metal impurities is to be reduced. Black dyes such as anthraquinone dyes (sometimes written as "anthraquinone"), azine dyes, azo dyes, disazo dyes, and chromium complex dyes may also be contained. When used in combination with yellow dyes such as methine dyes, disazo dyes, azocobalt complex dyes, and azochromium complex dyes, the color can be closer to that of a black pigment.

[0072] Furthermore, the composition may optionally contain a thermally expandable filler. The incorporation of a thermally expandable filler can improve the volumetric expansion coefficient of the composition of the present invention and may reduce uneven dispersion of the composition. Preferably, the thermally expandable filler has a core-shell structure, containing a volatile expanding agent within the shell of the core-shell structure. Here, a volatile expanding agent refers to a substance that generates gas at temperatures below the softening point of the shell. The thermally expandable filler has a structure in which a volatile expanding agent is encapsulated as a core agent within a shell with gas barrier properties. Therefore, the volatile expanding agent becomes gaseous upon exposure to heat, and the shell softens and expands. Examples of such components are exemplified in, for example, JP 2020-084094 A, and are available from Matsumoto Yushi Seiyaku Co., Ltd., such as FN-100SSD and FN-80GSD.

[0073] When the cured product obtained by curing the composition is used in magnetic components such as dust magnetic needles, coils, and electromagnetic wave shielding materials, magnetic particles may be included as component (C). Such magnetic particles contain one or more elements selected from the group consisting of Fe, Cr, Co, Ni, Ag, and Mn. In particular, soft magnetic particles may include magnetic particles made of iron (Fe), Fe—Si alloys, Fe—Al alloys, Fe—Ni alloys, Fe—Co alloys, Fe—Si—Al alloys, Fe—Si—Cr alloys, Fe—Cr alloys, carbonyl iron, stainless steel, etc. From the standpoint of availability, magnetic particles made of carbonyl iron may also be used. These magnetic particles may be surface-treated with a silane compound, titanate compound, aluminate compound, or a partial hydrolyzate thereof, as with the inorganic fillers described above, which may prevent deactivation of the curing catalyst or crosslinking agent and improve storage stability. In addition, these magnetic particles may have a surface coating layer containing a siloxane polymer, for example, by the method described in JP-A-2021-036013.

[0074] Furthermore, the present composition may contain other optional components, such as hot-melt fine particles (component D) other than component (A), a cure retarder (component E), or an adhesion promoter (component F), as long as the object of the present invention is not impaired.

[0075] Component (D) is a hot-melt fine particle other than component (A), and examples thereof include one or more selected from various hot-melt synthetic resins, waxes, fatty acid metal salts, etc. This wax component exhibits low kinematic viscosity at high temperatures (150°C) and forms a melt with excellent fluidity. Furthermore, when used in combination with components (A) to (C), the wax component in the melt of this composition rapidly spreads throughout the composition at high temperatures, thereby reducing the viscosity of the substrate surface to which the molten composition is applied and the entire composition, as well as rapidly reducing the surface friction between the substrate and the molten composition, thereby significantly increasing the fluidity of the entire composition. Therefore, adding only a small amount of this component relative to the total amount of the other components can significantly improve the viscosity and fluidity of the molten composition.

[0076] The wax component may be a petroleum wax such as paraffin, a natural wax such as carnauba wax, or a synthetic wax such as Montan acid ester wax, as long as it satisfies the above-mentioned conditions of dropping point and kinematic viscosity when melted. However, from the viewpoint of the technical effects of the present invention, a hot-melt component comprising a fatty acid metal salt or a fatty acid ester of an erythritol derivative is preferred, with metal salts of higher fatty acids such as stearic acid, palmitic acid, oleic acid, and isononanoic acid, as well as pentaerythritol tetrastearate, dipentaerythritol adipate stearate, glycerin tri-18-hydroxystearate, and pentaerythritol frustearate being particularly preferred. The type of fatty acid metal salt is not particularly limited, but suitable examples include alkali metal salts such as lithium, sodium, and potassium; alkaline earth metal salts such as magnesium, calcium, and barium; and zinc salts.

[0077] Particularly preferred wax components are fatty acid metal salts or erythritol derivatives with a free fatty acid content of 5.0% or less, and particularly preferably 4.0% or less, and 0.05 to 3.5%. Examples of such components include at least one metal stearate. Specifically, it is most preferred to use a hot-melt component with a melting point of 150°C or less, selected from calcium stearate (melting point 150°C), zinc stearate (melting point 120°C), magnesium stearate (melting point 130°C), pentaerythritol tetrastearate (melting point 60-70°C), pentaerythritol adipate stearate (melting point 55-61°C), pentaerythritol full stearate (melting point 62-67°C), etc.

[0078] The amount of wax component used, based on 100 parts by mass of the entire composition, is in the range of 0.01 to 5.0 parts by mass, or alternatively 0.01 to 3.5 parts by mass, or 0.01 to 3.0 parts by mass. If the amount of wax component used exceeds the upper limit, the adhesiveness and mechanical strength of the cured product obtained from the granular curable silicone composition of the present invention may be insufficient. If the amount used is less than the lower limit, sufficient fluidity may not be achieved when heated and melted.

[0079] Component (E) is a cure retarder that effectively suppresses side reactions, particularly when the present composition is cured by a hydrosilylation reaction, and may further improve the storage stability and usable life of the granular composition of the present invention when heated and melted.

[0080] Usable cure retarders are not particularly limited in structure or type, and can be selected from known hydrosilylation reaction inhibitors. Examples include alkyne alcohols such as 2-methyl-3-butyn-2-ol, 3,5-dimethyl-1-hexyn-3-ol, 2-phenyl-3-butyn-2-ol, and 1-ethynyl-1-cyclohexanol; eneyne 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; alkynyloxysilanes such as methyl-tris(1,1-dimethyl-2-propynyloxy)silane and vinyl-tris(1,1-dimethylpropynyloxy)silane; and bis(alkynyloxysilyl)alkanes represented by the following formula: (In the formula, R １ are independently alkynyl groups having 5 to 12 carbon atoms, and R ２ are independently an alkyl group having 1 to 3 carbon atoms or a hydrogen atom, and R ３ are independently an alkyl group having 1 to 3 carbon atoms, a is independently 1, 2, or 3, b is independently 0, 1, or 2, and a+b is 2 or 3, with the proviso that at least one b is 1 or 2, and n is an integer of 2 to 20.

[0081] In the above formula, R １ is the formula: an alkynyl group represented by the formula: or an alkynyl group represented by the formula: It is preferable that the alkynyl group is an alkynyl group represented by the following formula:

[0082] It is particularly preferable to use a compound with a boiling point of 200°C or higher at atmospheric pressure as component (E). From the standpoint of compositional homogenization, the granular composition of the present invention can be granulated through a process that involves heating, such as melt-kneading the composition. However, if a compound with a low boiling point is used as a retarder-curing agent, some or all of the cure retarder may volatilize during the melt-kneading or other process required for granulation, and the desired cure retardation effect may not be achieved in the final granular curable silicone composition. Note that methyl-tris(1,1-dimethyl-2-propynyloxy)silane and bis(alkynyloxysilyl)alkanes have boiling points of 245°C or higher and 300°C or higher, respectively, at atmospheric pressure, and are cited as suitable examples of component (F).

[0083] The amount of component (E) used is not limited, but is preferably within the range of 1 to 10,000 ppm by mass relative to the total composition.

[0084] Component (F) is an adhesion promoter, and is exemplified by organosilicon compounds containing at least one alkoxy group bonded to a silicon atom per molecule. Examples of this alkoxy group include methoxy, ethoxy, propoxy, butoxy, and methoxyethoxy groups, with methoxy being particularly preferred. Examples of groups bonded to silicon atoms in organosilicon compounds other than the alkoxy group include halogen-substituted or unsubstituted monovalent hydrocarbon groups such as alkyl, alkenyl, aryl, aralkyl, and halogenated alkyl groups; glycidoxyalkyl groups such as 3-glycidoxypropyl and 4-glycidoxybutyl; epoxycyclohexylalkyl groups such as 2-(3,4-epoxycyclohexyl)ethyl and 3-(3,4-epoxycyclohexyl)propyl; epoxyalkyl groups such as 3,4-epoxybutyl and 7,8-epoxyoctyl; acrylic-containing monovalent organic groups such as 3-methacryloxypropyl; and hydrogen atoms. The organosilicon compound preferably has a group capable of reacting with an alkenyl group or a silicon-bonded hydrogen atom in the composition, and more specifically, a silicon-bonded hydrogen atom or an alkenyl group. Furthermore, since this provides good adhesion to various substrates, the organosilicon compound preferably has at least one epoxy-containing monovalent organic group per molecule. Examples of such organosilicon compounds include organosilane compounds, organosiloxane oligomers, and alkyl silicates. Examples of the molecular structure of the organosiloxane oligomer or alkyl silicate include linear, partially branched linear, branched, cyclic, and network structures, with linear, branched, and network structures being particularly preferred.Examples of organosilicon compounds include silane compounds such as 3-glycidoxypropyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and 3-methacryloxypropyltrimethoxysilane; siloxane compounds having in one molecule at least one silicon-bonded alkenyl group or one silicon-bonded hydrogen atom, and one silicon-bonded alkoxy group; a mixture of a silane compound or siloxane compound having in one molecule at least one silicon-bonded alkoxy group and a siloxane compound having in one molecule at least one silicon-bonded hydroxy group and one silicon-bonded alkenyl group; a reaction mixture of an amino-containing organoalkoxysilane and an epoxy-containing organoalkoxysilane; an organic compound having in one molecule at least two alkoxysilyl groups and containing a bond other than a silicon-oxygen bond between the silyl groups; and compounds represented by the general formula: R. ａ ｎ Si(OR ｂ ) ４－ｎ (In the formula, R ａ is a monovalent epoxy group-containing organic group, and R ｂ is an alkyl group having 1 to 6 carbon atoms or a hydrogen atom. n is a number ranging from 1 to 3), or a partial hydrolysis condensate thereof; a reaction mixture of a vinyl group-containing siloxane oligomer (including those with a linear or cyclic structure) with an epoxy group-containing trialkoxysilane; methyl polysilicate, ethyl polysilicate, and epoxy group-containing ethyl polysilicate. This adhesion promoter is preferably a low-viscosity liquid, and although there are no limitations on its viscosity, it is preferably in the range of 1 to 500 mPa·s at 25°C. Furthermore, there are no limitations on the content of this adhesion promoter, but it is preferably in the range of 0.01 to 10 parts by mass per 100 parts by mass of the total composition.

[0085] In the present invention, a particularly suitable adhesion promoter is a reaction mixture of an amino-containing organoalkoxysilane and an epoxy-containing organoalkoxysilane. This component improves the initial adhesion of the curable silicone composition to various substrates that it comes into contact with during curing, and in particular the low-temperature adhesion of the composition to unwashed substrates. Such reaction mixtures are disclosed in Japanese Patent Publication No. 52-8854 and Japanese Patent Laid-Open Publication No. 10-195085.

[0086] Examples of alkoxysilanes having an amino group-containing organic group that constitute such a component include aminomethyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)aminomethyltributoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, and 3-anilinopropyltriethoxysilane.

[0087] Examples of epoxy group-containing organoalkoxysilanes include 3-glycidoxyprolyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and 2-(3,4-epoxycyclohexyl)ethylmethyldimethoxysilane.

[0088] The molar ratio of these alkoxysilanes having an amino group-containing organic group to those having an epoxy group-containing organic group is preferably within the range of (1:1.5) to (1:5), and particularly preferably within the range of (1:2) to (1:4). This component can be easily synthesized by mixing the above-mentioned alkoxysilanes having an amino group-containing organic group and alkoxysilanes having an epoxy group-containing organic group and reacting them at room temperature or under heat.

[0089] In particular, in the curable hot-melt silicone composition of the present invention, when an alkoxysilane having an amino group-containing organic group is reacted with an alkoxysilane having an epoxy group-containing organic group by the method described in JP-A-10-195085, a compound having the general formula: {In the formula, R 1 is an alkyl group, an alkenyl group, or an alkoxy group, and R 2 are the same or different general formula: (In the formula, R 4 is an alkylene group or an alkyleneoxyalkylene group, and R 5 is a monovalent hydrocarbon group, and R 6 is an alkyl group, and R 7 is an alkylene group, and R 8 is an alkyl group, an alkenyl group, or an acyl group, and a is 0, 1, or 2; 3 are the same or different hydrogen atoms or alkyl groups.} Examples of such carbasilatrane derivatives include carbasilatrane derivatives having a silicon-bonded alkoxy group or a silicon-bonded alkenyl group in one molecule, as shown in the following structure: (wherein Rc is a group selected from a methoxy group, an ethoxy group, a vinyl group, an allyl group, and a hexenyl group.)

[0090] In the present invention, a silatrane derivative represented by the following structural formula may also be used as an adhesion promoter. R in the formula 1 are the same or different hydrogen atoms or alkyl groups, and in particular, R 1 is preferably a hydrogen atom or a methyl group. 2 represents a hydrogen atom, an alkyl group, or a group represented by the general formula: -R 4 -Si(OR 5 ) x R 6 (3-x) are the same or different groups selected from the group consisting of alkoxysilyl group-containing organic groups represented by the formula:2 At least one of R is an alkoxysilyl group-containing organic group. 2 Examples of the alkyl group of R include a methyl group. 2 In the alkoxysilyl group-containing organic group, R 4 is a divalent organic group, and examples thereof include an alkylene group or an alkyleneoxyalkylene group, and particularly preferably an ethylene group, a propylene group, a butylene group, a methyleneoxypropylene group, or a methyleneoxypentylene group. 5 is an alkyl group having 1 to 10 carbon atoms, and is preferably a methyl group or an ethyl group. 6 is a substituted or unsubstituted monovalent hydrocarbon group, preferably a methyl group, and x in the formula is 1, 2, or 3, preferably 3.

[0091] Such an R 2 Examples of the alkoxysilyl group-containing organic group include the following groups: -(CH ２ ) ２ Si(OCH ３ ) ２ (CH ２ ) ２ Si(OCH ３ ) ２ CH ３ -(CH ２ ) ３ Si(OC ２ H ５ ) ２ (CH ２ ) ３ Si(OC ２ H ５ )(CH ３ ) ２ -CH ２ O(CH ２ ) ３ Si(OCH ３ ) ３ -CH ２ O(CH ２ ) ３ Si(OC ２ H ５ ) ３ -CH ２ O(CH ２ ) ３ Si(OCH３ ) ２ CH ３ -CH ２ O(CH ２ ) ３ Si(OC ２ H ５ ) ２ CH ３ -CH ２ OCH ２ Si(OCH ３ ) ２ CH ２ OCH ２ Si(OCH ３ )(CH ３ ) ２

[0092] R in the above formula 3 is at least one group selected from the group consisting of substituted or unsubstituted monovalent hydrocarbon groups, alkoxy groups having 1 to 10 carbon atoms, glycidoxyalkyl groups, oxiranylalkyl groups, and acyloxyalkyl groups; R 3 Examples of the monovalent hydrocarbon group of R include alkyl groups such as methyl groups. 3 Examples of the alkoxy group of R include a methoxy group, an ethoxy group, and a propoxy group. 3 An example of the glycidoxyalkyl group of R is a 3-glycidoxypropyl group. 3 Examples of the oxiranylalkyl group of R include a 4-oxiranylbutyl group and an 8-oxiranyloctyl group. 3 Examples of the acyloxyalkyl group include an acetoxypropyl group and a 3-methacryloxypropyl group. 3 is preferably an alkyl group, an alkenyl group, or an alkoxy group, more preferably an alkyl group or an alkenyl group, and particularly preferably a group selected from a methyl group, a vinyl group, an allyl group, and a hexenyl group.

[0093] The amount of component (F) used is not particularly limited, but from the viewpoint of improving adhesion to poorly adhesive substrates, it is preferably in the range of 0.1 to 1.0 mass %, and more preferably 0.2 to 1.0 mass %, of the entire composition. The amount of component (G) blended may be in the range of 5 to 50 mass parts, or may be in the range of 5 to 40 mass parts, per 100 mass parts of the total of components (A) and (B).

[0094] Furthermore, the present composition may contain other optional components, as long as they do not impair the object of the present invention, such as heat resistance agents such as iron oxide (red iron oxide), cerium oxide, cerium dimethylsilanolate, fatty acid cerium salts, cerium hydroxide, and zirconium compounds; dyes, pigments other than white, flame retardants, heat retardants such as aluminum hydroxide, magnesium hydroxide, zinc borate, zinc molybdate, and phosphazene; ion scavengers and pH adjusters such as hydrotalcite, bismuth oxide, and yttrium oxide; flame retardants such as magnesium chloride, zinc borate, zinc molybdate, phosphazene, etc.; antioxidants such as hindered phenol compounds, hindered amine compounds, thioether compounds, etc.; soft magnetic particles such as pure iron, silicon steel, iron-cobalt alloys, iron-nickel alloys, iron-chromium alloys, iron-aluminum alloys, carbonyl iron, stainless steel, or composite materials containing one or more of these; inorganic flame retardants (for example, hydrated metal compounds such as aluminum hydroxide), halogen-based flame retardants, phosphorus-based flame retardants, organic metal salt-based flame retardants, Silicone oil, silicone rubber, polyisoprene, polybutadienes such as 1,2-polybutadiene and 1,4-polybutadiene, styrene-butadiene rubber, acrylonitrile-butadiene rubber, carboxyl group-terminated butadiene acrylonitrile rubber, thermoplastic elastomers such as polychloroprene, poly(oxypropylene), poly(oxytetramethylene) glycol, polyolefin glycol and poly-ε-caprolactone, stress reducing agents such as polysulfide rubber and fluororubber, barium titanate (BaTiO ３ ), strontium titanate (SrTiO ３ ), lead zirconate titanate (Pb(Zr,Ti)O ３ , also known as PZT), alumina (Al ２ O３ , also known as aluminum oxide), zirconia (ZrO ２ , also known as zirconium dioxide), magnesia (MgO, also known as magnesium oxide), silica (SiO ２ , also known as silicon dioxide), titania (TiO ２ , also known as titanium dioxide), aluminum nitride (AlN), silicon nitride (Si ３ N ４ ), silicon carbide (SiC), barium calcium zirconate titanate (also known as BCTZ), polyvinylidene fluoride or other dielectric ceramics; metal salt stabilizers such as copper chloride, cupric iodide, copper acetate, and cerium stearate; antioxidants and heat stabilizers such as hindered amines, hindered phenols, sulfur-containing compounds, acrylates, and phosphorus-based organic compounds; ultraviolet absorbers, weathering agents, and light stabilizers such as benzophenones, salicylates, and benzotriazoles.

[0095] [Granular composition and tablet-molded product thereof] As described above, one of the features of the curable silicone composition of the present invention is that it is compositionally uniform and in the form of granules with a constant average particle size, and this granular composition can be further tableted using a known method to be used in the form of a pellet-shaped product or a tablet-shaped product. Unlike when a granular composition (mixture) such as that of Patent Document 1 is tableted, the granular curable silicone composition of the present invention is compositionally uniform, so using this granular composition not only provides excellent production efficiency for the tablet-molded product, but also has the advantage that the hot-melt properties, melt viscosity, physical properties of the cured product, and other aspects of the tablet-molded product obtained are even better.

[0096] Here, "pellets" and "tablets" are general names or common names for granular tablet-molded products made from a resin composition. The shape of the pellets / tablets is not limited, but is usually spherical, oval-spherical, or cylindrical. The size of the pellets is also not limited, but may have, for example, an average particle diameter or equivalent circle diameter of 500 μm or more, and may have an average particle diameter or equivalent circle diameter of 1 mm or more.

[0097] [Method for producing a granular curable silicone composition] The present composition is in the form of granules in which the entire composition containing at least the above-mentioned components (A) to (C) has been homogenized in terms of composition beyond the extent of simple mechanical mixing. Such a granular composition is preferably obtained by melt-kneading the entire composition accompanied by heating. More specifically, it is preferable to melt-knead components (A) to (C) and any other optional components at a temperature in the range of 50 to 150°C using a single- or twin-screw continuous mixer, a twin-roll mill, a Ross mixer, a kneader mixer, or the like, and then mold the mixture into granules for use. Specific examples of production methods are given below.

[0098] The method for producing a granular curable silicone composition of the present invention comprises the steps of melt-kneading a curable silicone composition comprising the above-described components (A) to (C) and any other optional components, wherein the content of component (C) is in the range of 400 to 3,000 parts by mass per 100 parts by mass of the combined components (A) and (B), at a temperature range of 50 to 150°C, and then molding the composition into granules having an average particle size in the range of 0.1 to 10.0 mm. The method is not particularly limited as long as the composition is molded into granules after melt-kneading, but it may, for example, include the following steps 1 to 3: Step 1: Kneading the components of the curable silicone composition while heating and melting them in a temperature range of 50 to 150°C; Step 2: Cooling the heated and melted mixture obtained in step 1 while discharging it; and Step 3: Cutting or breaking the mixture obtained in step 2 to mold a granular curable silicone composition.

[0099] [Step 1] Step 1 described above involves kneading the components of the curable silicone composition of the present invention while heating and melting them in a temperature range of 50 to 150°C. By heating and kneading the heat-meltable mixture at a temperature above its softening point, preferably in a temperature range of 50 to 120°C, the entire composition melts or softens, allowing components (A) to (C) and any optional components to be uniformly dispersed throughout.

[0100] The mixing device used in step 1 is not particularly limited, and may be a batch type heat-kneading device equipped with heating and cooling functions, such as a kneader, Banbury mixer, Henschel mixer, planetary mixer, two-roll mill, three-roll mill, Ross mixer, or Laboplastomill, or a continuous type heat-kneading device equipped with heating and cooling functions, such as a single-screw extruder or twin-screw extruder, and is selected based on the efficiency of processing time and the ability to control shear heat generation. From the perspective of processing time, the device may be a continuous type heat-kneading device such as a single-screw extruder or twin-screw extruder, or a batch type mixer such as a Laboplastomill. However, from the standpoint of production efficiency of the granular curable silicone composition, continuous type heat-kneading devices such as a single-screw extruder or twin-screw extruder are preferably used.

[0101] This mixture is then granulated in step 3 after passing through step 2. If the temperature is below the lower limit, softening will be insufficient, making it difficult to obtain a molten or softened mixture in which the components are uniformly dispersed throughout, even when mechanical force is used. Such a mixture may not have excellent uniformity among the components, and when the resulting granular curable silicone composition is used in a molding process, a uniform cured product may not be obtained. Conversely, if the temperature exceeds the upper limit, the curing agent may react during mixing, causing the entire mixture to significantly thicken or harden, losing its hot-melt properties and forming a cured product, which is undesirable. For this reason, when a hydrosilylation reaction component is used as component (B), it is preferable to use a particulate hydrosilylation reaction catalyst (e.g., the above-mentioned component (B2)) dispersed or encapsulated in a thermoplastic resin whose softening point is above the kneading temperature.

[0102] The components of the present invention can be fed into the kneading device described above by either feeding each component separately into the kneading device at a constant rate, or by mechanically or other means powder-mixing all of the components to form a granular curable silicone composition, which can then be fed into the kneading device.

[0103] [Step 2] Step 2 is a step in which the mixture melted and kneaded in step 1 is discharged from the kneader. The mixture may be discharged in any shape, but since the mixture is cut and broken into granules in step 3, it is preferable that the mixture be in a shape that allows for easy cutting and breaking. Examples include a rod shape (strand shape) with a diameter of about 0.5 to 5.0 mm or a sheet shape with a thickness of about 0.5 to 5.0 mm. Since the mixture is preferably a non-sticky solid for granulation in step 3, the temperature of the discharged mixture must be lowered to near room temperature by natural cooling or rapid cooling. Examples of rapid cooling methods include a method using a cooler or water cooling.

[0104] [Step 3] Step 3 is a step in which the mixture discharged in step 2 is cut or broken to form granules. If the mixture is hard enough to be broken by shear stress alone at room temperature, it can be broken and granulated by passing it through a two-roll mill or the like. The size and shape of the granules obtained in step 3 can be adjusted to some extent by controlling the dimensions of the mixture discharged in step 2 and the gap between the rolls, and in the present invention, the average particle size of the granular molded product must be in the range of 0.1 to 10.0 mm. Furthermore, if the mixture cannot be broken down using a roll or the like, it is also possible to obtain granules by discharging the mixture as a rod-shaped mixture in step 2 and cutting it to a predetermined size using a rotary cutter or the like while cooling.

[0105] The granular curable silicone composition obtained by the production method of the present invention has excellent flowability when hot melted and is highly uniform in composition, so that the composition is less likely to become non-uniform or to physically move during molding such as compression molding, press molding, and lamination. This has the advantage that the entire composition can be easily molded uniformly, making it suitable for use in molding processes that do not generate shear pressure. Furthermore, because the above advantages are not lost even when the granular composition is subjected to secondary molding, the granular curable silicone composition may be compressed or tableted using a tablet press or the like and used as tablets or pellets for transfer molding.

[0106] [Cured Product] The above-mentioned granular curable silicone composition or tablet-formed product thereof possesses hot-melt properties, exhibits excellent flowability during melting (hot-melt), ease of handling, and curing properties, and upon curing forms a cured product suitable for semiconductor components, etc. Depending on the type of curing agent (B), the curing method can be selected from known curing methods such as heat curing, photocuring with high-energy rays such as ultraviolet light, and moisture curing. However, when component (B) is selected from a thermal radical polymerization initiator such as an organic peroxide and a hydrosilylation reaction catalyst / its hydrosilylation reaction crosslinking agent, curing by heat curing in the range of 80°C to 200°C is preferred. Note that in the present invention, the physical properties of the cured product, such as the linear expansion coefficient, flexural strength, and hardness, can be easily designed to fall within the following preferred ranges based on the type of component (A) and the quantitative range of component (C).

[0107] [Linear Expansion Coefficient of Cured Product] The cured product obtained by curing the composition has an average linear expansion coefficient of 30 ppm / °C or less, preferably 20 ppm / °C or less, in the temperature range of 25°C to 200°C. Within this range, the difference in average linear expansion coefficient from the substrate to be used is small, so that residual stress in the obtained integrally molded product can be reduced, and device reliability can be improved.

[0108] [Flexural Strength of Cured Product] Furthermore, since the cured product is suitable as an encapsulant for semiconductors, which requires high hardness and strength, the flexural strength of the cured product measured by the method specified in JIS K 6911-1995 "General Testing Methods for Thermosetting Plastics" is preferably 15 MPa or more, or 20 MPa or more.

[0109] [Hardness of the Cured Product] Because the composition is suitable for use as a protective material for semiconductors, etc., the cured product obtained by curing the composition preferably has a Type D durometer hardness at 25°C of at least 20. The Type D durometer hardness is determined using a Type D durometer in accordance with JIS K 6253-1997 "Testing method for hardness of vulcanized rubber and thermoplastic rubber."

[0110] [Method of Molding a Cured Product] The present composition (including the granular composition and its tablet-formed pellets or tablets, the same applies hereinafter) can be cured by a method comprising at least the following steps (I) to (III): (I) a step of heating the present composition to 100°C or higher to melt it; (II) a step of injecting the curable silicone composition softened in step (I) into a mold, or a step of dispersing the curable silicone composition obtained in step (I) in the mold by clamping; and (III) a step of curing the curable silicone composition injected in step (II).

[0111] The present composition exhibits a relatively low melt viscosity at temperatures of 100°C or higher, and therefore has excellent hot-melt properties, flowability, and gap-filling properties under pressure, making it suitable for use in molding methods including a coating step in which overmolding and underfilling of semiconductor elements are performed simultaneously (the so-called mold underfill method).

[0112] Furthermore, due to the above-mentioned properties, the present composition can be suitably used in a molding method including a coating step (so-called wafer molding) in which the composition covers the surface of a semiconductor substrate (including a wafer substrate) on which one or more semiconductor elements are mounted, and overmoldes the surface so that the gaps between the semiconductor elements are filled with the cured product.

[0113] In the molding step, a transfer molding machine, a compression molding machine, an injection molding machine, a press molding machine, an auxiliary ram molding machine, a slide molding machine, a double ram molding machine, a low-pressure encapsulation molding machine, or the like can be used.

[0114] In step (III) above, the curable silicone composition injected (applied) in step (II) is cured. The curing method varies depending on the type of component (B), but when component (B) is selected from a thermal radical polymerization initiator such as an organic peroxide and a hydrosilylation reaction catalyst / its hydrosilylation reaction crosslinking agent, curing is preferably carried out by heat curing in the range of 80°C to 200°C. In particular, when an organic peroxide is used as component (B), the heating temperature is preferably 150°C or higher, or 170°C or higher.

[0115] [Uses of the Composition] The granular curable silicone composition of the present invention (including its tablet-shaped or pellet-shaped tableted product) has good hot-melt properties and excellent flowability during melting (hot-melt), ease of handling, and curing properties, making it suitable for use as an encapsulant or underfill agent for semiconductors; an encapsulant or underfill agent for power semiconductors such as SiC or GaN; an encapsulant or light-reflecting material for optical semiconductors such as light-emitting diodes, photodiodes, phototransistors, and laser diodes; and an adhesive or protective agent for electrical and electronic applications. Furthermore, because the composition has hot-melt properties, it is also suitable as a material for transfer molding, compression molding, press molding, or injection molding. It is particularly suitable for use as an encapsulant for semiconductors that are molded using mold underfill or wafer molding methods.

[0116] As described above, the present composition is suitable as a sealant for semiconductors, and by using the composition to replace part or all of a conventionally known sealant in the process of sealing semiconductors and the like by molding methods such as an overmolding method using a conventionally known sealant (including non-silicone hot-melt sealants such as epoxy sealants), an underfill method, a mold underfill method in which these are performed at the same time, or a wafer molding method, it is possible to produce semiconductor / optical components such as semiconductor packages, power semiconductor modules, MEMS, small integrated devices such as microsensors (fingerprint sensors), magnetic components such as coils containing magnetic particles, flexible substrates (stretchable wiring boards) used in wearable devices, and optical waveguides connected to electrical wiring boards and connectors. For example, the curable silicone composition according to the present invention is disclosed in Japanese Patent Application Laid-Open No. 2021-097123, Japanese Patent Application Laid-Open No. 2021-024945, Japanese Patent Application Laid-Open No. 2020-132771, Japanese Patent Application Laid-Open No. 2020-132750, Japanese Patent Application Laid-Open No. 2020-125399, Japanese Patent Application Laid-Open No. 2020-123670, Japanese Patent Application Laid-Open No. 2020-084094, Japanese Patent Application Laid-Open No. 2020-088055, Japanese Patent Application Laid-Open No. 2019-006905, Japanese Patent Application Laid-Open No. 2018-188494, Japanese Patent Application Laid-Open No. 2017-179185, Japanese Patent Application Laid-Open No. 2020-023643, Japanese Patent Application Laid-Open No. 2020-063459, Japanese Patent Application Laid-Open No. 2020-090634, Japanese Patent Application Laid-Open No. 2020-088055, It can be used in place of some or all of the sealants (especially silicone elastomer sealants, pastes containing functional fillers, and hot-melt sealants) described in JP 2020-107767, JP 2021-080411, JP 2021-036013, JP 2020-152844, JP 2020-158684, JP 2021-019031, JP 2021-059741, JP 2020-057775, JP 2021-015985, JP 2015-114390, JP 2016-177106, etc. If necessary, the technical elements applied to these sealant compositions may be applied to the present invention, and the composition of the present invention may be adjusted in terms of its composition, physical properties and melting characteristics of the cured product, etc., and is preferred.

[0117] [Uses of the cured product] There are no particular restrictions on the uses of the cured product of the present invention, but the granular curable silicone composition of the present invention (including its tablet-shaped or pellet-shaped products) has hot-melt properties and excellent moldability, and the resulting cured product has excellent adhesive properties, a high modulus of elasticity, and a low coefficient of linear expansion. For this reason, the cured product of the present invention can be suitably used as a component for semiconductor devices, and can be suitably used as an encapsulant for semiconductor elements, IC chips, etc., or as a light-reflecting material for optical semiconductor devices.

[0118] The semiconductor device equipped with a member made of the cured product of the present invention is not particularly limited, but is preferably a semiconductor device mounted on a power semiconductor device, an optical semiconductor device, or a flexible semiconductor device that is stretchable or deformable.

[0119] The hot-melt curable silicone composition of the present invention and its production method are described in detail below using examples and comparative examples. In the formula, Me, Ph, and Vi represent methyl, phenyl, and vinyl groups, respectively. The softening point and melt viscosity of the curable silicone composition of each example and comparative example were measured using the following methods. The curable silicone composition was heated at 180°C for 2 hours to produce a cured product, and the adhesive strength to various substrates was measured using the following method. The results are shown in Table 1.

[0120] [Softening Point of Curable Silicone Composition] The curable silicone composition was molded into a cylindrical pellet measuring φ14 mm x 22 mm. This pellet was placed on a hot plate set to 25°C to 100°C, and a 100 gram load was applied from above for 10 seconds. After the load was removed, the deformation of the pellet was measured. The softening point was determined as the temperature at which the deformation in the height direction reached 1 mm or more.

[0121] [Melt Viscosity] The melt viscosity of the curable silicone composition at 180°C was measured using a Koka-shiki Flow Tester CFT-500EX (manufactured by Shimadzu Corporation) under a pressure of 100 kgf using a nozzle with a diameter of 1.0 mm.

[0122] [Flexural Strength of Cured Product] A cured product was produced by heating the curable silicone composition for 2 hours at 180° C. The flexural strength of this cured product was measured according to the method specified in JIS K 6911-1995 "General Testing Methods for Thermosetting Plastics."

[0123] [Linear expansion coefficient curve of cured product] A cured product was produced by curing the curable silicone composition of Example 1 using the method described above. The linear expansion coefficient of this cured product was measured over a temperature range of 20°C to 200°C using a TM9200 manufactured by Shinku Riko Co., Ltd.

[0124] The main components containing the component (A) of the present invention were prepared by the methods shown below in Reference Examples 1 to 5. The presence or absence of hot-melt properties of the component (A) used was evaluated based on the presence or absence of softening point / melt viscosity.

[0125] [Reference Example 1] In a 1 L flask, a white solid having the average unit formula: (PhSiO ３ / ２ ) ０.８０ (Me ２ ViSiO １ / ２ ) ０.２０ A toluene solution of resinous organopolysiloxane (1) was prepared by dissolving 550 g of a resinous organopolysiloxane represented by the formula (I) in 450 g of toluene. The molecular weight (Mw) of this resinous organopolysiloxane (1) measured by GPC in a toluene solvent was 1,600, its softening point was 100°C, and its viscosity, measured at 150°C using a rotational viscometer, was 30 Pa s.

[0126] Reference Example 2: Hot-melt organopolysiloxane resin fine particles (P1) A toluene solution of the resinous organopolysiloxane (1) prepared in Reference Example 1 was spray-dried at 40°C to remove the toluene, thereby preparing spherical hot-melt organopolysiloxane resin fine particles (P1). When the fine particles were observed under an optical microscope, they had a particle size of 5 to 10 μm and an average particle size of 7.9 μm.

[0127] For use in comparative experiments, a resinous organosiloxane block copolymer C1 having resinous and linear siloxane block structures within the molecule was prepared by the method shown in Reference Example 3, and organopolysiloxane resin microparticles (C1) were prepared by the method shown in Reference Example 4. The presence or absence of hot-melt properties was evaluated based on the presence or absence of softening point / melt viscosity.

[0128] [Reference Example 3] In a 500 mL four-necked round-bottom flask, ３／２ ) ｎ(where n is a positive number such that Mw is 1500) was added to a flask under a nitrogen atmosphere. 318.6 g of a toluene solution of a phenyl resin (217 Flake manufactured by Dow Corning) (solid concentration: 56.5 wt %, Si: 1.318 mol) was added. The flask was equipped with a thermometer, a Teflon stirring blade, and a Dean-Stark apparatus (previously filled with toluene) connected to a water-cooled condenser. The reaction mixture of the above components was heated under reflux for 30 minutes, and 0.54 g of water was removed. The reaction solution was cooled to 108°C, followed immediately by the addition of 224.24 g of a methylphenylpolysiloxane capped with MTA / ETA, which had been synthesized by adding 50 / 50 MTA / ETA (methyltriacetoxysilane / ethyltriacetoxysilane, 4.24 g, Si: 0.0187 mol) to a methylphenylpolysiloxane capped with silanol groups at both ends of the chain (220 g, Si: 1.614 mol, DP = 181) and stirring at room temperature for 1 hour in a glove box. The reaction mixture was heated under reflux in a nitrogen atmosphere for 2 hours to remove 2.01 g of water. The reaction solution was again cooled to 108°C, and vinylmethyldiacetoxysilane (11.91 g, Si: 0.0633 mol) was added, followed by refluxing for 1 hour to remove 1.05 g of water. The reaction mixture was then cooled to 90°C, deionized water (47.8 g) was added, and the mixture was refluxed to remove water by azeotropic distillation. The reaction mixture was then cooled again to 108°C, and 50 / 50 MTA / ETA (methyltriacetoxysilane / ethyltriacetoxysilane) (21.57 g, Si: 0.0949 mol) was added. After refluxing for 1 hour, the reaction mixture was cooled to 90°C, deionized water (47.8 g) was added, and the mixture was refluxed to remove water by azeotropic distillation. (This water addition and removal procedure was repeated twice.) The same water treatment was repeated three times, and finally, volatiles (103.6 g) were removed by distillation at 118°C, increasing the solids content of the reaction mixture to approximately 70%.

[0129] The above process resulted in the synthesis of a resin-like organosiloxane block copolymer C1, which had a resinous and linear siloxane block structure within its molecule. The copolymer C1 was colorless and transparent and contained 2 mol% vinyl groups. Its molecular weight (Mw) measured by GPC in toluene was 89,571, its softening point was 100°C, and its viscosity measured by a rotational viscometer at 150°C was 10,000 Pa·s.

[0130] [Reference Example 4] The organosiloxane block copolymer C1 was pulverized by spray drying while removing the toluene, to obtain spherical resin-like organosiloxane block copolymer microparticles (C1). When the obtained powder was observed under an optical microscope, it was found to be a spherical powder with a diameter of 5 to 10 μm.

[0131] [Reference Example 5] In a 1 L flask, a white solid having the average unit formula: (PhSiO ３ / ２ ) ０.８０ (Me ２ ViSiO １ / ２ ) ０.２０ 100 g of a resinous organopolysiloxane represented by the formula: HMe ２ SiO(Ph ２ SiO)SiMe ２ 3.0 g of a diphenylsiloxane terminated at both molecular chain ends with dimethylhydrogensiloxy groups and having a viscosity of 5 mPa s, represented by H (content of silicon-bonded hydrogen atoms = 0.6 mass%), with an average unit formula: (PhSiO ３ / ２ ) ０.４ (HMe ２ SiO １ / ２ ) ０.６ A liquid silicone mixture (L1) was obtained by mixing 28.0 g of a branched-chain organopolysiloxane having two or more silicon-bonded hydrogen atoms per molecule and a viscosity of 25 mPa s (silicon-bonded hydrogen atom content = 0.65 mass%), represented by the formula:

[0132] [Examples 1 to 3, Production Example 1 (Comparative Example 1), Production Examples 2 and 3, and Examples 1, 2, and 3 were conducted using the hot-melt organopolysiloxane resin microparticles (P1) obtained in Reference Example 2 and the liquid silicone mixture obtained in Reference Example 5. For comparison, an experiment in Comparative Example 2 was conducted using the organosiloxane block copolymer microparticles (C1) obtained in Reference Example 4. The compositions of Production Example 1 (Comparative Example 1) and Example 1 were subjected to a pressure test at 5 MPa using a hot press set at 180°C, and the state of the crushed compositions is shown in Figures 1 and 2.

[0133] [Production Example 1 (Comparative Example 1)] 1,394.0 g of fused silica having an average particle size of 14.5 μm (S6105P manufactured by Nippon Steel Materials Micron Co., Ltd.), 153 g of fused silica having an average particle size of 0.7 μm (SPH507M manufactured by Nippon Steel Materials Micron Co., Ltd.), 1.7 g of Denka Black Pressed Product (manufactured by Denka Co., Ltd.), 1.7 g of calcium stearate (manufactured by Kawamura Chemicals Co., Ltd.), and a crystalline silica having the formula: Me ２ ViSiO(Me ２ SiO) ２９ Si(OMe) ３ 5.7 g of dimethylpolysiloxane represented by the formula: (ViMe) was added all at once to a small pulverizer and stirred at 100°C for 1 minute to subject the fused silica to a surface treatment, and the temperature of the pulverizer was then returned to 25°C. Next, 57.2 g of the hot-melt organopolysiloxane resin fine particles (P1) obtained in Reference Example 2 and ２ SiO １／２ ) ０．７５ (PhSiO ３／２ ) ０．２５ 5.7 g of a branched organopolysiloxane containing vinyl groups at its molecular terminals and having a viscosity of 5 mPa·s (vinyl group content=23% by mass), represented by the formula: HMe ２ SiO(Ph ２ SiO)SiMe ２ 2.9 g of a diphenylsiloxane terminated at both molecular chain ends with dimethylhydrogensiloxy groups and having a viscosity of 5 mPa s, represented by H (content of silicon-bonded hydrogen atoms = 0.6 mass%), with an average unit formula: (PhSiO３ / ２ ) ０.４ (HMe ２ SiO １ / ２ ) ０.６ 22.3 g of a branched-chain organopolysiloxane having two or more silicon-bonded hydrogen atoms per molecule and a viscosity of 25 mPa·s (silicon-bonded hydrogen atom content=0.65% by mass), {an amount such that the diphenylsiloxane and branched phenylsiloxane contain 1.0 mole of silicon-bonded hydrogen atoms per 1.0 mole of vinyl groups in the composition}, methyltris-1,1-dimethyl-2-propynyloxysilane (boiling point=245°C (1013.25 hPa, an amount such that the amount is 300 ppm by mass relative to the composition), bis(trimethoxysilylpropoxymethyl)vinylsilatrane (boiling point=245°C (1013.25 hPa, an amount such that the amount is 300 ppm by mass relative to the composition), 0.06 parts by mass of a thermoplastic polycarbonate resin (softening point = 150°C) containing 4000 ppm of platinum (Pt (zero valent) 1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex) was added to a small grinder and stirred at room temperature (25°C) for 1 minute to prepare a uniform, granular black-and-white curable silicone composition. Observation of the resulting granular composition with an optical microscope revealed that most particles had a particle size of 10 to 100 μm. Furthermore, the melt viscosity of this composition at 180°C was 17 Pa·s. Figure 1 shows a diagram of the resulting granular curable silicone composition crushed at a pressure of 5 MPa in a press set at 180°C. Furthermore, the flexural strength and linear expansion coefficient of the cured product of the resulting curable silicone composition were measured using the methods described above and found to be 52 MPa and 13 ppm / °C, respectively.

[0134] Example 1 The curable silicone composition obtained in Production Example 1 was charged into a kneader mixer set to 90°C and melt-kneaded for 5 minutes, resulting in a solid composition at room temperature. This solid was cooled to 0°C and pulverized to produce an amorphous granular curable silicone composition. Observation of the resulting granular composition under an optical microscope revealed that most of the granules were granules with particle diameters of 1.0 to 5.0 mm, with an average particle diameter of 2.2 mm. The melt viscosity of this composition at 180°C was 17 Pa·s. Figure 2 shows a diagram of the resulting granular curable silicone composition crushed at a pressure of 5 MPa in a press set to 180°C. The flexural strength and linear expansion coefficient of the cured product of the resulting curable silicone composition were measured using the methods described above and found to be 54 MPa and 12 ppm / °C, respectively.

[0135] [Comparative Example 2-1] 360 g of fused silica having an average particle size of 14.5 μm (S6105P manufactured by Nippon Steel Materials Micron Co., Ltd.), 40 g of fused silica having an average particle size of 0.7 μm (SPH507M manufactured by Nippon Steel Materials Micron Co., Ltd.), 0.5 g of Denka Black Pressed Product (manufactured by Denka Co., Ltd.), 0.5 g of calcium stearate (manufactured by Kawamura Chemicals Co., Ltd.), and a sintered body having a viscosity of 23 mPa·s and the formula: Me ２ ViSiO(Me ２ SiO) ２９ Si(OMe) ３ 1.5 g of a dimethylpolysiloxane represented by the following formula: ３ / ２ ) ０.４ (HMe ２ SiO １ / ２ ) ０.６9.1 g of a branched-chain organopolysiloxane having two or more silicon-bonded hydrogen atoms per molecule and a viscosity of 25 mPa·s (silicon-bonded hydrogen atom content=0.65% by mass), {an amount such that the diphenylsiloxane and branched phenylsiloxane contain 1.0 mole of silicon-bonded hydrogen atoms per 1.0 mole of vinyl groups in the composition}, methyltris-1,1-dimethyl-2-propynyloxysilane (boiling point=245°C (1013.25 hPa, an amount such that the amount is 300 ppm by mass relative to the composition), bis(trimethoxysilylpropoxymethyl)vinylsilatrane (boiling point=245°C (1013.25 hPa, an amount such that the amount is 300 ppm by mass relative to the composition), 0.025 parts by mass of a thermoplastic polycarbonate resin (softening point = 150°C) containing 4000 ppm platinum (1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex of Pt (zero valence)) was added to a small grinder and stirred at room temperature (25°C) for 1 minute to prepare a uniform, granular black curable silicone composition. The melt viscosity of this composition at 180°C was 3400 Pa s.

[0136] Comparative Example 2-2 The curable silicone composition obtained in Comparative Example 2-1 was charged into a kneader mixer set to 90°C and melt-kneaded for 5 minutes, resulting in a unified composition that was solid at room temperature. This solid was then cooled to 0°C and pulverized to produce an amorphous granular curable silicone composition. When the obtained granular composition was observed with an optical microscope, most of the particles were granules with a particle size of 1.0 to 5.0 mm. Furthermore, the melt viscosity of this composition at 180°C was 3000 Pa s.

[0137] [Production Example 2] 1,394.0 g of fused silica having an average particle size of 14.5 μm (S6105P manufactured by Nippon Steel Materials Micron Co., Ltd.), 153 g of fused silica having an average particle size of 0.7 μm (SPH507M manufactured by Nippon Steel Materials Micron Co., Ltd.), 1.7 g of Denka Black Pressed Product (manufactured by Denka Co., Ltd.), 1.7 g of calcium stearate (manufactured by Kawamura Chemicals Co., Ltd.), and a crystalline silica having the formula: Me ２ ViSiO(Me ２ SiO) ２９ Si(OMe) ３5.7 g of dimethylpolysiloxane represented by the following formula was added all at once to a small pulverizer and stirred at 100°C for 1 minute to subject the fused silica to a surface treatment, and the temperature of the pulverizer was then returned to 25°C. Next, 88.1 g of the liquid silicone mixture (L1) obtained in Reference Example 5, methyltris-1,1-dimethyl-2-propynyloxysilane (boiling point = 245°C (1013.25 hPa, an amount equivalent to 300 ppm by mass of the composition), 5.7 g of bis(trimethoxysilylpropoxymethyl)vinylsilatrane, and 0.06 parts by mass of thermoplastic polycarbonate resin (softening point = 150°C) containing 4000 ppm platinum in the form of a 1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex of Pt (zero valence) were added to a small grinder and stirred at room temperature (25°C) for 1 minute to prepare a uniform, granular black curable silicone composition. When the resulting granular composition was observed under an optical microscope, most of the particles had a particle size of 10 to 100 μm.

[0138] [Production Example 3] 1,394.0 g of fused silica having an average particle size of 14.5 μm (S6105P manufactured by Nippon Steel Materials Micron Co., Ltd.), 153 g of fused silica having an average particle size of 0.7 μm (SPH507M manufactured by Nippon Steel Materials Micron Co., Ltd.), 1.7 g of Denka Black Pressed Product (manufactured by Denka Co., Ltd.), 1.7 g of calcium stearate (manufactured by Kawamura Chemicals Co., Ltd.), and a crystalline silica having the formula: Me ２ ViSiO(Me ２ SiO) ２９ Si(OMe) ３5.7 g of dimethylpolysiloxane represented by the following formula was added all at once to a small pulverizer and stirred at 100°C for 1 minute to subject the fused silica to a surface treatment, and the temperature of the pulverizer was then returned to 25°C. Next, 88.1 g of the liquid silicone mixture (L1) obtained in Reference Example 5, methyltris-1,1-dimethyl-2-propynyloxysilane (boiling point = 245°C (1013.25 hPa, an amount equivalent to 600 ppm by mass relative to the composition), and 5.7 g of bis(trimethoxysilylpropoxymethyl)vinylsilatrane and 1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex of Pt (zero valence) (an amount equivalent to 5 ppm platinum relative to the composition) were added to a small grinder and stirred at room temperature (25°C) for 1 minute to prepare a uniform, granular black curable silicone composition. When the obtained granular composition was observed under an optical microscope, it was found that most of the particles had a particle size of 10 to 100 μm.

[0139] Example 2 The curable silicone composition obtained in Production Example 2 was charged into a kneader mixer set to 90°C and melt-kneaded for 5 minutes, resulting in a solid composition at room temperature. This solid was cooled to 0°C and pulverized to produce an amorphous granular curable silicone composition. When the obtained granular composition was observed under an optical microscope, it was found that most of the granules were 1.0 to 5.0 mm in particle size, with an average particle size of 1.9 mm. The melt viscosity of this composition at 180°C was 25 Pa·s. The flexural strength and linear expansion coefficient of the cured product made from the obtained curable silicone composition were measured using the methods described above and were 62 MPa and 12 ppm / °C, respectively.

[0140] Example 3 The curable silicone composition obtained in Production Example 3 was charged into a kneader mixer set to 90°C and melt-kneaded for 2 minutes, resulting in a solid composition at room temperature. This solid was cooled to 0°C and pulverized to produce an amorphous granular curable silicone composition. When the obtained granular composition was observed under an optical microscope, it was found that most of the granules were 1.0 to 5.0 mm in particle size, with an average particle size of 1.4 mm. The melt viscosity of this composition at 180°C was 170 Pa·s. The flexural strength and linear expansion coefficient of the cured product made from the obtained curable silicone composition were measured using the methods described above and were 59 MPa and 12 ppm / °C, respectively.

[0141]

[0142] [Summary] In Examples 1 to 3 of the present invention, granular curable silicone compositions that were compositionally uniform and had an average particle size in the range of 1 to 5 mm were obtained by melt kneading. These compositions had excellent hot-melt properties and low melt viscosity at 180°C. Furthermore, when evaluated by hot pressing, the crushed composition was uniform, with no separation of the silicone component and inorganic filler observed. For this reason, the granular compositions of Examples 1 to 3 are expected to have particularly excellent gap-filling properties and be suitable for use in encapsulating semiconductors and the like by compression molding or press molding.

[0143] Furthermore, in Examples 1 and 2, which used a curing catalyst that was not soluble in the components of the composition but that became active in the composition upon stimulation with thermal energy above 80°C, the melt viscosity of the granular curable silicone compositions obtained by melt-kneading was sufficiently low, whereas the melt viscosity of the composition of Example 3, which did not use a curing catalyst that became active in the composition upon stimulation with thermal energy above 80°C, was relatively high. This is thought to be because the reaction proceeded during melt-kneading, causing a slight increase in viscosity.

[0144] On the other hand, the composition of Comparative Example 1 (precursor of Example 1, corresponding to the example of Patent Document 1, etc.), which is a granular mixture that has not undergone melt-kneading, has a low melt viscosity at 180 ° C, but is not homogenized, so it becomes non-uniform during hot pressing, and separation of silicone component and inorganic filler is observed.In addition, in Comparative Example 2, which uses organosiloxane block copolymer microparticles (C1) having resinous and chain-like block structures in the molecule, even if melt-kneading is carried out in the same manner as in Example 1, when containing the same amount of inorganic filler, the melt viscosity at 180 ° C is too high, so sufficient fluidity cannot be obtained, and there is a concern that it is not suitable for the molding process that needs to fill small gaps or allow material to flow to a certain extent.

[0145] In Production Example 1 (Comparative Example 1) and Comparative Example 2-1, fine granular curable silicone compositions with particle sizes of 100 μm or less were obtained, but in Examples 1 to 3 and Comparative Example 2-2, granular curable silicone compositions with particle sizes of 100 μm or more were produced. In particular, in Examples 1 to 3, by forming the composition into granules with particle sizes of 100 μm or more, it is possible to prevent dust from flying around during use, which is expected to improve handleability during sealing processes, etc.

Claims

1. (A) RSiO ３／２ (wherein R is a monovalent hydrocarbon group) is an organopolysiloxane resin containing siloxane units represented by the formula (I) in an amount of at least 20 mol % of all siloxane units. (B) a curing agent, and (C) a functional inorganic filler; and the content of the component (C) is 400 to 3,000 parts by mass per 100 parts by mass of the total of the components (A) and (B), It is solid at 25°C and has a melt viscosity of 200 Pa s or less at 180°C as measured by a flow tester. A granular curable silicone composition having an average particle size in the range of 0.1 to 10.0 mm.

2. The granular curable silicone composition according to claim 1, characterized in that the curable silicone composition is melt-kneaded in the temperature range of 50 to 150°C to homogenize its composition, and then molded into granules.

3. 2. The granular curable silicone composition according to claim 1, wherein component (B) is a curing agent that is insoluble in the other components of the composition at room temperature and contains a curing reaction catalyst that becomes active in the composition when stimulated with thermal energy at 80°C or higher.

4. The component (B) is (B1) an organic peroxide having a half-life of 10 hours at a temperature of 80°C or higher, and (B2) Hydrosilylation reaction catalyst-containing thermoplastic resin particles containing a thermoplastic resin having a softening point or glass transition point of 80° C. or higher 2. The granular curable silicone composition according to claim 1, further comprising one or more curing agents selected from the group consisting of:

5. 2. The granular curable silicone composition according to claim 1, wherein component (A) has a weight-average molecular weight (Mw) of 20,000 or less.

6. At least a part or all of the component (A) is (A1) A curing agent having a softening point of 30°C or higher, a curing reactive functional group containing at least one carbon-carbon double bond in the molecule, and RSiO ３／２ 2. The granular curable silicone composition according to claim 1, which is a hot-melt organopolysiloxane resin containing siloxane units represented by the formula: (wherein R is a monovalent hydrocarbon group) in an amount of at least 20 mol % of all siloxane units.

7. At least a part or all of the component (A) is (A1-1) A curing agent having a softening point of 30°C or higher, a curing reactive functional group containing at least one carbon-carbon double bond in the molecule, and RSiO ３／２ 2. The granular curable silicone composition according to claim 1, which is a hot-melt organopolysiloxane resin containing siloxane units represented by the formula: (wherein R is a monovalent hydrocarbon group) in an amount of at least 20 mol % of all siloxane units, and in which at least 10 mol % of the silicon-bonded organic groups are aryl groups.

8. 2. The granular curable silicone composition according to claim 1, wherein component (C) is a reinforcing filler, a white pigment, a thermally conductive filler, an electrically conductive filler, a phosphor, or a mixture of at least two of these.

9. 2. The granular curable silicone composition according to claim 1, which upon curing gives a cured product having a flexural strength of at least 15 MPa, as measured according to the method specified in JIS K 6911-1995, "General Testing Methods for Thermosetting Plastics."

10. A pellet-shaped or tablet-shaped product obtained by tableting the granular curable silicone composition according to any one of claims 1 to 9.

11. A cured product obtained by curing the granular curable silicone composition according to any one of claims 1 to 9, or the pellet-shaped or tablet-shaped product according to claim 10.

12. A member for a semiconductor device, comprising the cured product of claim 11.

13. A semiconductor device comprising the cured product of claim 11.

14. (A) RSiO ３／２ (wherein R is a monovalent hydrocarbon group) is an organopolysiloxane resin containing siloxane units represented by the formula (I) in an amount of at least 20 mol % of all siloxane units. (B) a curing agent, (C) Functional inorganic filler a step of melt-kneading a curable silicone composition containing 400 to 3,000 parts by mass of component (C) per 100 parts by mass of the total of components (A) and (B) at a temperature range of 50 to 150°C, and then molding the composition into granules having an average particle size in the range of 0.1 to 10.0 mm.

10. A method for producing the granular curable silicone composition according to claim 1, comprising:

15. A method for molding a cured product, comprising at least the following steps (I) to (III): (I) a step of heating the granular curable silicone composition according to any one of claims 1 to 9, or the pellet-shaped or tablet-shaped product according to claim 10, to 100°C or higher to melt it; (II) a step of injecting the curable silicone composition softened in step (I) into a mold or a step of clamping the mold to distribute the curable silicone composition obtained in step (I) throughout the mold; and (III) A step of curing the curable silicone composition injected in the step (II).

16. 16. A method for molding a cured product according to claim 15, comprising a coating step in which overmolding and underfilling of a semiconductor element are carried out in one step with a cured product obtained by curing the granular curable silicone composition according to any one of claims 1 to 9, or the pellet-shaped or tablet-shaped product according to claim 10.

17. 16. A method for molding a cured product according to claim 15, comprising a coating step of overmolding a surface of a semiconductor substrate carrying one or more semiconductor elements with a cured product obtained by curing the granular curable silicone composition according to any one of claims 1 to 9, or the pellet-shaped or tablet-shaped product according to claim 10, so that the cured product covers the surface of the semiconductor substrate and fills gaps between the semiconductor elements.