Curable silicone composition, adhesive and optical semiconductor device

Abstract

The curable silicone composition comprises the following: (A) an organopolysiloxane containing alkenyl groups with at least two alkenyl groups per molecule; (B) an organohydrogenpolysiloxane with at least two hydrogen atoms bonded to silicon atoms per molecule; (C) a thermally conductive filler in an amount of 5% by mass or more, based on the total mass of the composition; (D) an organopolysiloxane containing cerium; and (E) a curing catalyst.

Description

[TECHNICAL FIELD]

[0001] The present invention relates to a curable silicone composition and, in particular, to a curable silicone composition suitable for use in adhesives for optical semiconductors. The present invention also relates to an optical semiconductor device comprising an adhesive consisting of a cured product of the curable silicone composition.

[0002] The present patent application claims priority on the basis of patent application No. 2023-127893, which was filed in Japan on August 4, 2023, the contents of which are incorporated herein by reference. [State of the art]

[0003] When cured, curable silicone compounds form hardened products with excellent heat resistance, cold resistance, electrical insulation properties, weather resistance, water repellency, and transparency, and are therefore used in a wide range of industrial fields. In particular, these cured products are less prone to discoloration compared to other organic materials, and their physical properties, such as durability, deteriorate less. This makes them suitable for optical materials and especially widespread as silicone sealing materials used in optical semiconductor devices, such as light-emitting diodes (LEDs).

[0004] It is well known that cerium-containing organopolysiloxanes can be added to improve the heat resistance and / or light resistance of cured products of such curable silicone compositions.

[0005] For example, patent specification 1 discloses a curable silicone composition comprising at least the following: (A) a linear organopolysiloxane having at least two alkenyl groups per molecule; (B) an organopolysiloxane represented by the following average unit formula: (R 1 SiO 3 / 2 ) a (R 1 2SiO 2 / 2 ) b (R 1 3SiO 1 / 2 ) c (SiO 4 / 2 ) d (XO 1 / 2 ) e (in the formula R 1 each independently of each other C 1-12 -Alkyl groups, C 2-12 -Alkenyl groups, C 6-20 -Aryl groups, C 7-20-Aralkyl groups or one of these groups in which some or all of the hydrogen atoms are substituted with halogen atoms, except that at least two R 1per molecule alkenyl groups; X is a hydrogen atom or an alkyl group; a is a number from 0 to 0.3; b is 0 or a positive number; c is a positive number; d is a positive number; e is a number from 0 to 0.4; and a + b + c + d = 1, c / d is a number from 0 to 10, and b / d is a number from 0 to 0.5) {in an amount that results in a mass ratio of component (A) and component (B) of 1 / 99 to 99 / 1}; (C) an organopolysiloxane with at least two hydrogen atoms bonded to silicon atoms per molecule {in an amount such that the content of silicon-bonded hydrogen atoms in this component is 0.1 to 10 mol per mol of all alkenyl groups in components (A) and (B) combined}; (D) an organopolysiloxane containing cerium {in such an amount that the content of cerium atoms in component (D) is 20 to 2.000 ppm, based on mass units and relative to the total mass of the composition}; and (E) a catalytic amount of a catalyst for the hydrosilylation reaction.

[0006] Patent specification 2 also discloses a curable white silicone composition comprising: (A) an organopolysiloxane having at least 2 alkenyl groups per molecule; (B) a cerium-containing organopolysiloxane; (C) a white pigment; and (D) a curing catalyst.

[0007] However, one problem with conventional thermosetting silicone compositions is that the inclusion of a large amount of a thermally conductive filler, such as aluminum oxide, leads to a loss of thermal stability as well as a loss of strength after aging at elevated temperatures. [Previous technical documents][Patent specifications] [Patent 1] Japanese translation of international PCT patent application no. 2016-513165 [Patent Specification 2] Unexamined Japanese Patent Notice No. 2021-88678 [Abstract of Invention] [Problem solved by the invention]

[0008] One object of the present invention is to provide a curable silicone composition capable of forming a cured product that exhibits better thermal stability, even when a large amount of a thermally conductive filler is included.

[0009] Another object of the present invention is to provide a sealing material comprising the curable silicone composition of the present invention. Yet another object of the present invention is to provide an optical semiconductor device sealed with the sealing material of the present invention. [Means of solving the tasks]

[0010] As a result of extensive research to solve the problems described above, the inventors arrived at the present invention with the surprising discovery that a curable silicone composition comprising a cerium-containing organopolysiloxane is able to form a cured product that exhibits better thermal stability, even when a large amount of a thermally conductive filler is included.

[0011] The present invention therefore relates to a curable silicone composition comprising the following: (A) an organopolysiloxane containing alkenyl groups with at least two alkenyl groups per molecule; (B) an organohydrogen polysiloxane with at least two hydrogen atoms bonded to silicon atoms per molecule (C) a thermally conductive filler in an amount of 5% by mass or more, based on the total mass of the composition; (D) a cerium-containing organopolysiloxane; and (E) a hardening catalyst

[0012] The (A) alkenyl group-containing organopolysiloxane preferably contains an MQ resin.

[0013] The (C) thermally conductive filler is preferably a metal oxide.

[0014] The (C) thermally conductive filler preferably comprises two thermally conductive fillers with different average particle sizes.

[0015] The content of cerium atoms of the (D) cerium-containing organopolysiloxane is preferably 1 to 100 ppm, based on the total mass of all organopolysiloxane components in the composition.

[0016] The present invention also relates to an adhesive comprising the curable silicone composition according to the present invention.

[0017] The present invention also relates to an optical semiconductor device comprising the adhesive according to the present invention. [Advantageous effect of the invention]

[0018] The curable silicone composition according to the present invention is able to form a cured product that has better thermal stability, even when a large amount of a thermally conductive filler is included. [Types of embodiment of the invention][Curable silicone composition]: The curable silicone composition according to the present invention comprises at least the following: (A) an organopolysiloxane containing alkenyl groups with at least two alkenyl groups per molecule; (B) an organohydrogen polysiloxane with at least two hydrogen atoms bonded to silicon atoms per molecule (C) a thermally conductive filler in an amount of 5% by mass or more, based on the total mass of the composition; (D) a cerium-containing organopolysiloxane; and (E) a hardening catalyst

[0019] The components of the curable silicone composition of the present invention are described in detail below.

[0020] (A) An organopolysiloxane containing alkenyl groups with at least two alkenyl groups per molecule. Component (A) is a curable organopolysiloxane with at least two alkenyl groups per molecule. The curable silicone composition according to the present invention may comprise an organopolysiloxane (A) containing alkenyl groups, or it may comprise organopolysiloxanes (A) containing at least two alkenyl groups.

[0021] Examples of the molecular structure of component (A) include linear, slightly branched, resinous, cyclic, and 3D network structures. Component (A) may be an organopolysiloxane with such a molecular structure or a mixture of at least two such organopolysiloxanes. In this description, the term "resinous" means the presence of a branched structure or a 3D network structure in the molecular structure.

[0022] The curable silicone composition of the present invention preferably comprises a resinous organopolysiloxane containing alkenyl groups as component (A). The curable silicone composition of the present invention also preferably comprises an organopolysiloxane containing linear alkenyl groups as component (A). The curable silicone composition of the present invention also preferably comprises both a resinous organopolysiloxane containing alkenyl groups and an organopolysiloxane containing linear alkenyl groups as component (A).

[0023] Examples of the alkenyl groups in component (A) include C2-12 alkenyl groups, such as vinyl, allyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, undecenyl and dodecenyl groups, and preferably vinyl.

[0024] Examples of groups bonded to a silicon atom other than alkenyl groups in component (A) include, optionally halogen-substituted monovalent hydrocarbon groups that are not alkenyl groups; C1-12 alkyl groups, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, cyclohexyl, heptyl, octyl, nonyl, decyl, undecyl, and dodecyl groups; C6-20 aryl groups, such as phenyl, tolyl, xylyl, and naphthyl groups; and C7-20 aralkyl groups, such as benzyl, phenethyl, and phenylpropyl groups. and each of these groups in which some or all of the hydrogen atoms are substituted with halogen atoms, such as fluorine, chlorine and bromine atoms.The silicon atoms in component (A) may also comprise a small amount of hydroxyl or alkoxy groups, such as methoxy or ethoxy groups, provided that this does not impair the objectives of the present invention. Groups bonded to a silicon atom other than alkenyl groups in component (A) are preferably selected from C1-6 alkyl groups, and in particular methyl.

[0025] In one embodiment of the present invention, component (A) can contain a resinous organopolysiloxane containing alkenyl groups as component (A-1). The (A-1) resinous organopolysiloxane containing alkenyl groups can preferably be represented by average unit formula (Ia): (R 1 3SiO 1 / 2 ) a (R 1 2SiO 2 / 2 ) b (R 1 SiO 3 / 2 ) c (SiO 4 / 2 ) d (XO 1 / 2 ) e (in formula (Ia) R1 the same or different, optionally halogen-substituted, monovalent hydrocarbons, wherein at least two R 1 per molecule alkenyl groups, and 0 ≤ a < 1, 0 ≤ b < 1, 0 ≤ c < 0.9, 0 ≤ d < 0.5 and 0 ≤ e < 0.4, and a + b + c + d = 1.0 and c + d > 0. The symbol e represents the number of (X0) groups when the total number of silicon atoms is 1 (ratio of the number of (X0) groups to the total number of silicon atoms).

[0026] -Examples of the monovalent hydrocarbon groups of R, possibly halogen-substituted 1in the formula (Ia) above, the following are included: C1-12 alkyl groups, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, cyclohexyl, heptyl, octyl, nonyl, decyl, undecyl, and dodecyl groups; C6-20 aryl groups, such as phenyl, tolyl, xylyl, and naphthyl groups; C7-20 aralkyl groups, such as benzyl, phenethyl, and phenylpropyl groups; C2-12 alkenyl groups, such as vinyl, allyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, undecenyl, and dodecenyl groups; and each of these groups in which some or all of the hydrogen atoms are substituted with halogen atoms, such as fluorine, chlorine, and bromine atoms. R 1They may also include a small amount of hydroxyl or alkoxy groups, such as methoxy or ethoxy groups, provided that this does not impair the objectives of the present invention. 1 are preferably selected under C1-6 alkyl groups and in particular methyl or C2-6 alkenyl groups and in particular vinyl.

[0027] X in the formula (Ia) above is a hydrogen atom or an alkyl group. Preferred examples of alkyl groups represented by X include C1-3 alkyl groups, in particular methyl, ethyl, and propyl groups. X is preferably a hydrogen atom.

[0028] In the formula (Ia) above, a is preferably in the range of 0.1 ≤ a ≤ 0.8, particularly preferably in the range of 0.2 ≤ a ≤ 0.7, and even more preferably in the range of 0.3 ≤ a ≤ 0.6. In the formula (Ia) above, b is preferably in the range of 0 ≤ b ≤ 0.5, particularly preferably in the range of 0 ≤ b ≤ 0.3, and especially in the range of 0 ≤ b ≤ 0.1. In the formula (Ia) above, c is preferably in the range of 0 ≤ c ≤ 0.5, particularly preferably in the range of 0 ≤ c ≤ 0.3, and especially in the range of 0 ≤ c ≤ 0.1. In formula (Ia), d is preferably in the range of 0.1 ≤ d ≤ 0.8, particularly preferably in the range of 0.2 ≤ d ≤ 0.7 and even more preferably in the range of 0.3 ≤ d ≤ 0.6. In the formula (Ia) above, e is preferably in the range of 0 ≤ e ≤ 0.15, particularly preferably in the range of 0 ≤ e ≤ 0.1 and especially in the range of 0 ≤ e ≤ 0.05.

[0029] In a preferred embodiment of the present invention, the structure of the resinous alkenyl group-containing organopolysiloxane of component (A-1) includes a siloxane unit (Q-unit) consisting of SiO 4 / 2 The structure of the resinous, alkenyl-group-containing organopolysiloxane of component (A-1) can be represented by siloxane units (D units) linked by SiO₂. 2 / 2 are reproduced, or contain none, and preferably none. The structure of the resinous alkenyl group-containing organopolysiloxane of component (A-1) can include siloxane units (T units) linked by SiO₂. 3 / 2 be reproduced, or contain none, and preferably none.

[0030] In a preferred embodiment of the present invention, the resinous organopolysiloxane containing alkenyl groups of component (A-1) contains molecularly terminal alkenyl groups. The resinous organopolysiloxane of component (A-1) preferably has alkenyl groups in siloxane units (M units) connected by SiO₂. 1 / 2 can be reproduced, and may have alkenyl groups in the side chains of the molecular chain or none, preferably but none (especially siloxane units (D units)) that are connected by SiO 2 / 2 are reproduced, and siloxane units (T units) represented by SiO 3 / 2 (be reproduced).

[0031] In a preferred embodiment of the present invention, the resinous, alkenyl-group-containing organopolysiloxane of component (A) contains an MQ resin or consists solely of an MQ resin. MQ resins are organopolysiloxanes consisting solely of siloxane units (M units) connected by SiO₂. 1 / 2are reproduced, and consist of siloxane units (Q units) that are composed of SiO₂ 4 / 2 The MQ resin of component (A-1) can preferably be represented by the following average unit formula (Ib).

[0032] Average unit formula (Ib): (R 1 3SiO 1 / 2 ) s (SiO 4 / 2 ) t (XO 1 / 2 ) u In the formula, R 1 the same or different, possibly halogen-substituted, monovalent hydrocarbon groups, except that at least two R 1 per molecule alkenyl groups are; 0 < s < 1.0 < t < 1.0 ≤ u < 0.4 and s + t = 1.0; and u is the number of (XO) groups when the total number of silicon atoms is 1 (ratio of the number of (XO) groups to the total number of silicon atoms).

[0033] R 1 in formula (II-b) is defined as in formula (II-a).

[0034] In formula (II-b), s is preferably in the range of 0.2 ≤ s ≤ 0.8, particularly preferably in the range of 0.3 ≤ s ≤ 0.7, and even more preferably in the range of 0.4 ≤ s ≤ 0.6. In formula (II-b) above, t is preferably in the range of 0.2 ≤ t ≤ 0.8, particularly preferably in the range of 0.3 ≤ t ≤ 0.7, and especially in the range of 0.3 ≤ t ≤ 0.7. In formula (II-b) above, u is preferably in the range of 0 ≤ u ≤ 0.3, particularly preferably in the range of 0 ≤ u ≤ 0.2, and especially in the range of 0 ≤ u ≤ 0.1.

[0035] The content of alkenyl groups in all organic groups bonded to a silicon atom of the resinous, alkenyl-group-containing organopolysiloxane of component (A-1) is not particularly limited, but may be, for example, 3 mol% or more, preferably 5 mol% or more, and particularly preferably 10 mol% or more of the total organic groups bonded to a silicon atom, and may be 40 mol% or less, preferably 30 mol%, and particularly preferably 20 mol% or less of the total organic groups bonded to a silicon atom. The content of alkenyl groups can be determined by analysis such as Fourier-transform infrared spectroscopy (FT-IR) or nuclear magnetic resonance (NMR), or by the titration method described below.

[0036] A method for quantifying alkenyl groups in components using a titration procedure is described. The content of alkenyl groups in organopolysiloxane components can be accurately quantified using a titration procedure commonly known as the Wijs method. The principles are described below. First, the alkenyl groups in the organopolysiloxane starting material and iodine monochloride undergo an addition reaction, as shown in equation (1). Then, according to the reaction shown in equation (2), an excess amount of iodine monochloride is reacted with potassium iodide, releasing iodine. The released iodine is then titrated with a sodium thiosulfate solution. CH2=CH- + 2ICl → CH2I-CHCl- + ICl (excess) Formula (1): ICl+KI → I2 + KCl Formula (2):

[0037] The amount of alkenyl groups in the components can be quantified from the difference between the amount of sodium thiosulfate required for the titration and the amount of a separately prepared blank solution.

[0038] The MQ resin of component (A-1) can be a solid at ambient temperature (25 °C).

[0039] If component (A) contains at least one (A-1) resinous organopolysiloxane, its content is not particularly limited, but is preferably 1 wt% or more, more preferably 3 wt% or more, and particularly preferably 5 wt% or more, based on the total mass of the curable silicone composition of the present invention. The content of component (A-1) is preferably 70 wt% or less, more preferably 60 wt% or less, and even more preferably 50 wt% or less, based on the total mass of the curable silicone composition. In the present description, numerical ranges can be specified using any combination of upper and lower limits of the numerical range.

[0040] Component (A) may contain a linear alkenyl group-containing organopolysiloxane as component (A-2). The linear alkenyl group-containing organopolysiloxane of component (A-2) may preferably be represented by average structural formula (Ic): R 1 3SiO(R 1 2SiO 2 / 2 ) m SiR 2 3 (in formula (Ic) R 1 the same or different, possibly halogen-substituted, monovalent hydrocarbon groups, provided that at least two R 1 per molecule alkenyl groups and m is 1 to 500).

[0041] In the formula above (Ic), the same groups as in the formula above (Ia) can be used for the monovalent hydrocarbon groups of R, which may be halogen-substituted. 1 be used.

[0042] In the formula (Ic) above, m is preferably 2 to 300, more preferably 5 to 200, even more preferably 10 to 100 and particularly preferably 15 to 50.

[0043] Examples of this component (A-2) include: dimethylpolysiloxanes terminating at both ends of the molecular chain with dimethylvinylsiloxy groups, dimethylpolysiloxanes terminating at both ends of the molecular chain with diphenylvinylsiloxy groups, dimethylsiloxane-methylphenylsiloxane copolymers terminating at both ends of the molecular chain with dimethylvinylsiloxy groups, dimethylsiloxane-diphenylsiloxane copolymers terminating at both ends of the molecular chain with dimethylvinylsiloxy groups, dimethylsiloxane-methylphenylsiloxane copolymers terminating at both ends of the molecular chain with diphenylvinylsiloxy groups, dimethylsiloxane-methylvinylsiloxane copolymers terminating at both ends of the molecular chain with dimethylvinylsiloxy groups, Dimethylsiloxane-methylphenylsiloxane-methylvinylsiloxane copolymers, which are terminated at both ends of the molecular chain with dimethylvinylsiloxy groups, dimethylsiloxane-diphenylsiloxane-methylvinylsiloxane copolymers,which are terminated at both ends of the molecular chain with dimethylvinylsiloxy groups, methylvinylpolysiloxane which is terminated at both ends of the molecular chain with trimethylsiloxy groups, methylvinylsiloxane-methylphenylsiloxane copolymers which are terminated at both ends of the molecular chain with trimethylsiloxy groups, methylvinylsiloxane-diphenylsiloxane copolymers which are terminated at both ends of the molecular chain with trimethylsiloxy groups, and dimethylsiloxane-methylvinylsiloxane copolymers which are terminated at both ends of the molecular chain with trimethylsiloxy groups.

[0044] In a preferred embodiment of the present invention, the linear organopolysiloxane containing linear alkenyl groups of component (A-2) can be a linear organopolysiloxane that is terminated at both ends of the molecular chain by alkenyl groups and has alkenyl groups at both molecular ends. The linear organopolysiloxane of component (A-2) can contain any alkenyl groups in side chains of the molecular chain (in particular D units) or none, but preferably none.

[0045] The content of alkenyl groups in the linear organopolysiloxane of component (A-2) (mol% of alkenyl groups in all functional groups bonded to a silicon atom of the linear organopolysiloxane) can be designed as desired, but can normally be 1 mol% or more, preferably 2 mol% or more, and particularly preferably 3 mol% or more, and can also be 20 mol% or less, preferably 15 mol% or less, and particularly preferably 10 mol% or less. The content of alkenyl groups can be determined by analysis such as Fourier-transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR), and the titration methods described above.

[0046] If component (A) contains at least one linear organopolysiloxane (A-2), the content is not particularly limited, but is preferably 1 wt% or more, more preferably 2 wt% or more, and particularly preferably 3 wt% or more, based on the total mass of the curable silicone composition of the present invention. The content of component (A-2) is also preferably 50 wt% or less, more preferably 40 wt% or less, and even more preferably 30 wt% or less, based on the total mass of the curable silicone composition of the present invention.

[0047] In one embodiment, aryl groups are either present in a small amount in the organic groups bonded to a silicon atom of component (A) or are not present at all. In particular, the content of aryl groups in all organic groups bonded to a silicon atom can be 10 mol% or less, 5 mol% or less, 3 mol% or less, or 1 mol% or less.

[0048] The viscosity of the alkenyl group-containing organopolysiloxane (A) can be from 5 mPa·s to 5,000 mPa·s and preferably from 10 mPa·s to 500 mPa·s at 25 °C, but is not specifically limited thereto. As used in the present description, the viscosity of the organopolysiloxane component can be determined using a rotational viscometer according to JIS K 7117-1.

[0049] The mass-averaged molecular mass (Mw) of the alkenyl group-containing organopolysiloxane (A) is, for example, in the range of 1,000 to 100,000 and preferably from 1,500 to 15,000, but is not specifically limited thereto. As used in the present description, the mass-averaged molecular mass can be determined by GPC.

[0050] The total content of component (A) is not particularly limited, but is preferably 3% by mass or more, more preferably 5% by mass or more, and more preferably 10% by mass or more, based on the total mass of the curable silicone composition. The content of component (A) may also be 90% by mass or less, more preferably 80% by mass or less, and more preferably 70% by mass or less, based on the total mass of the curable silicone composition.

[0051] (B) Organohydrogen polysiloxane with at least two hydrogen atoms bonded to silicon atoms per molecule Component (B) is an organohydrogen polysiloxane that acts as a crosslinking agent for the curable silicone composition via a hydrosilylation curing reaction and has at least two hydrogen atoms bonded to silicon atoms per molecule. The curable silicone composition according to the present invention can comprise one (B) organohydrogen polysiloxane, or it can comprise at least two (B) organohydrogen polysiloxanes.

[0052] Examples of the molecular structure of component (B) are linear, slightly branched, resinous, cyclic, and 3D network structures. Component (B) can be an organohydrogen polysiloxane with such a molecular structure or a mixture of at least two such organohydrogen polysiloxanes. The curable silicone composition of the present invention preferably comprises a linear organohydrogen polysiloxane as component (B).

[0053] Examples of groups bonded to a silicon atom other than hydrogen atoms bonded to a silicon atom that contain component (B) include, optionally halogen-substituted, monovalent hydrocarbon groups that are not alkenyl groups; C1-12 alkyl groups, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, cyclohexyl, heptyl, octyl, nonyl, decyl, undecyl, and dodecyl groups; C6-20 aryl groups, such as phenyl, tolyl, xylyl, and naphthyl groups; and C7-20 aralkyl groups, such as benzyl, phenethyl, and phenylpropyl groups. and each of these groups in which some or all of the hydrogen atoms are substituted with halogen atoms, such as fluorine, chlorine and bromine atoms.The silicon atoms in component (B) may also comprise a small amount of hydroxyl or alkoxy groups, such as methoxy or ethoxy groups, provided that this does not impair the objectives of the present invention. The groups bonded to a silicon atom other than hydrogen atoms bonded to a silicon atom in component (B) may be selected from C1-6 alkyl groups, and in particular methyl.

[0054] In one embodiment of the present invention, component (B) can contain a linear organohydrogen polysiloxane as component (B-1). The linear organohydrogen polysiloxane of component (B-1) can preferably be represented by average structural formula (II): R 2 3SiO(R 2 2SiO 2 / 2 ) n SiR 2 3 (in formula (II) R 2Hydrogen atoms or the same or different, optionally halogen-substituted, other monovalent hydrocarbon groups than alkenyl groups, except that at least two R 2 per molecule are hydrogen atoms and n is 1 to 200).

[0055] Examples of monovalent hydrocarbon groups, possibly halogen-substituted, that are not alkenyl groups, represented by R 2as represented in formula (II), include: C1-12 alkyl groups, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, cyclohexyl, heptyl, octyl, nonyl, decyl, undecyl, and dodecyl groups; C6-20 aryl groups, such as phenyl, tolyl, xylyl, and naphthyl groups; C7-20 aralkyl groups, such as benzyl, phenethyl, and phenylpropyl groups; and any of these groups in which some or all of the hydrogen atoms are substituted with halogen atoms, such as fluorine, chlorine, and bromine atoms. 2 They may also include a small amount of hydroxyl or alkoxy groups, such as methoxy or ethoxy groups, provided that this does not impair the objectives of the present invention. 2 is preferably selected from hydrogen atoms and C1-6 alkyl groups, and in particular methyl.

[0056] In formula (II) n is preferably 2 to 150 and particularly preferably 5 to 100.

[0057] In a preferred embodiment of the present invention, the linear organohydrogen polysiloxane of component (B-1) has hydrogen atoms bonded to a silicon atom at both ends of the molecular chain. The linear organohydrogen polysiloxane of component (B-1) has one hydrogen atom bonded to a silicon atom in M ​​units and may contain one hydrogen atom bonded to a silicon atom in D units or none, preferably none.

[0058] In one embodiment, aryl groups are either present in a small amount in the organic groups bonded to a silicon atom of component (B) or are not present at all. In particular, the content of aryl groups in all organic groups bonded to a silicon atom can be 10 mol% or less, 5 mol% or less, 3 mol% or less, or 1 mol% or less.

[0059] The content of component (B) is not particularly limited, but is preferably 1% by mass or more, more preferably 2% by mass or more, and more preferably 3% by mass or more, based on the total mass of the curable silicone composition. In a preferred embodiment, the content of component (B) is 30% by mass or less, more preferably 20% by mass or less, and more preferably 15% by mass or less, based on the total mass of the curable silicone composition.

[0060] In one embodiment of the present invention, component (B) can be contained such that the ratio (H / Ar) of hydrogen atoms bonded to a silicon atom to the alkenyl groups bonded to a silicon atom in the organopolysiloxane components of component (B) is 0.5 mol or more, preferably 0.7 mol or more, particularly preferably 1 mol or more and particularly 1.2 mol or more hydrogen atoms bonded to a silicon atom per mol alkenyl groups bonded to a silicon atom in the curable silicone composition, and can also be contained such that the ratio is, for example, 5 mol or less, preferably 3 mol or less, more preferably 2.5 mol or less and even more preferably 2 mol or less hydrogen atoms bonded to a silicon atom per mol alkenyl groups bonded to a silicon atom in the curable silicone composition. (C) Thermally conductive filler

[0061] The thermally conductive filler, which serves as component (C), is a component that provides the desired thermal conductivity to the curable silicone composition of the present invention. The curable silicone composition according to the present invention can comprise one (C) thermally conductive filler, or it can comprise at least two (C) thermally conductive fillers.

[0062] Examples of component (C) may be selected from the group consisting of pure metals, alloys, metal oxides, metal hydroxides, metal nitrides, metal carbides, metal silicides, carbon, soft magnetic alloys, and ferrites. Component (C) preferably comprises at least one powder and / or fiber, wherein metal powder, metal oxide powder, metal nitride powder, or carbon powder are preferred.

[0063] Examples of pure metals include bismuth, lead, tin, antimony, indium, cadmium, zinc, silver, copper, nickel, aluminum, iron, and metallic silicon. Examples of alloys include at least two metals selected from the group consisting of bismuth, lead, tin, antimony, indium, cadmium, zinc, silver, copper, nickel, aluminum, iron, and metallic silicon. Examples of metal oxides include aluminum oxide (alumina), zinc oxide, silica, magnesium oxide, beryllium oxide, chromium oxide, and titanium oxide. Examples of metal hydroxides include magnesium hydroxide, aluminum hydroxide, barium hydroxide, and calcium hydroxide. Examples of metal nitrides include boron nitride, aluminum nitride, and silicon nitride. Examples of metal carbides include silicon carbide, boron carbide, and titanium carbide. Examples of metal silicides include magnesium silicide, titanium silicide, zirconium silicide, tantalum silicide, niobium silicide, chromium silicide, tungsten silicide, and molybdenum silicide.Examples of carbon include diamond, graphite, fullerenes, carbon nanotubes, graphene, activated carbon, and amorphous carbon black. Examples of soft magnetic alloys include Fe-Si alloys, Fe-Al alloys, Fe-Si-Al alloys, Fe-Si-Cr alloys, Fe-Ni alloys, Fe-Ni-Co alloys, Fe-Ni-Mo alloys, Fe-Co alloys, Fe-Si-Al-Cr alloys, Fe-Si-B alloys, and Fe-Si-Co-B alloys. Examples of ferrites include Mn-Zn ferrites, Mn-Mg-Zn ferrites, Mg-Cu-Zn ferrites, Ni-Zn ferrites, Ni-Cu-Zn ferrites, and Cu-Zn ferrites.

[0064] The component (C) is preferably selected from metal oxides and can in particular be selected from aluminium oxide (alumina), zinc oxide, silica, magnesium oxide, beryllium oxide, chromium oxide and titanium oxide.

[0065] Examples of the configuration of component (C) include spherical, needle-shaped, disc-shaped, rod-shaped and irregularly shaped, and preferably spherical, but not specifically limited thereto.

[0066] The average primary particle size of component (C) is not particularly limited, but is preferably in the range of 0.01 to 50 µm, more preferably in the range of 0.01 to 20 µm, and even more preferably in the range of 0.1 to 5 µm. As used in this description, the average particle size means the particle size of 50% of all particles (D50) in the particle size distribution as determined by laser diffraction / scattering.

[0067] In a preferred embodiment of the present invention, component (C) comprises two thermally conductive fillers having different average particle sizes. In the present embodiment, component (C) preferably comprises a combination of component (C-1) with an average particle size of 2 µm or less and component (C-2) with an average particle size of more than 2 µm. The average particle size range of component (C-1), which has a smaller average particle size, is preferably 0.01 to 1.5 µm and particularly preferably 0.1 to 1 µm. The average particle size range of component (C-2), which has a larger average particle size, is preferably 2.5 to 20 µm and particularly preferably 3 to 5 µm.

[0068] The content of the thermally conductive filler in component (C) is preferably 5% by mass or more, based on the total mass of the curable silicone composition. The content of the thermally conductive filler in component (C) is also preferably 7% by mass or more, and more preferably 10% by mass or more, based on the total mass of the curable silicone composition. In a preferred embodiment, the content of component (C) is 90% by mass or less, and more preferably 80% by mass or less, based on the total mass of the curable silicone composition.

[0069] In another embodiment, the content of the thermally conductive filler of component (C) is 20% or more by mass, 30% or more by mass, 40% or more by mass, 50% or more by mass, 60% or more by mass, or 70% or more by mass, based on the total mass of the curable silicone composition. The content of component (C) is also 90% or less by mass, and preferably 80% or less by mass, based on the total mass of the curable silicone composition.

[0070] If component (C) contains components (C-1) and (C-2) with different particle sizes, the ratio of these components is not particularly limited, but the mass ratio of component (C-2) to component (C-1) is usually in the range of 1:10 to 10:1, preferably in the range of 1:5 to 5:1, and particularly preferably in the range of 1:3 to 3:1. In a preferred embodiment, component (C-2) is present in a larger quantity than component (C-1), for example, in a mass ratio of component (C-2) to component (C-1) in the range of 1 to 10:1, preferably 1.25 to 5:1, and particularly preferably 1.5 to 3:1. (D) organopolysiloxane containing cerium,

[0071] The curable silicone composition according to the present invention comprises a cerium-containing organopolysiloxane as component (D). The cerium-containing organopolysiloxane (D) can be obtained, for example, by a reaction between cerium chloride or a cerium salt of a carboxylic acid and an alkali metal salt of a silanol-containing organopolysiloxane. Consequently, the term “cerium-containing organopolysiloxane,” as used in the present description, can mean a substance obtained by reacting a silanol-containing organopolysiloxane and a cerium salt, wherein the silanol group of the organopolysiloxane and the cerium atom are chemically bonded.

[0072] Examples of cerium salts of a carboxylic acid include cerium 2-ethylhexanoate, cernaphthenate, ceroleate, cerlaurate, and cerstearate. An example of a cerium chloride is cerium trichloride.

[0073] Examples of alkali metal salts of organopolysiloxanes containing silanol groups include potassium salts of diorganopolysiloxanes terminating at both ends of the molecular chain with silanol groups, sodium salts of diorganopolysiloxanes terminating at both ends of the molecular chain with silanol groups, potassium salts of diorganopolysiloxanes terminating at one end of the molecular chain with a silanol group and at the other end of the molecular chain with a triorganosiloxy group, and sodium salts of diorganopolysiloxanes terminating at one end of the molecular chain with a silanol group and at the other end of the molecular chain with a triorganosiloxy group.Furthermore, examples of groups bonded to a silicon atom in these organopolysiloxanes include C1-12 alkyl groups, such as methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, neopentyl, hexyl, cyclohexyl, heptyl, octyl, nonyl, decyl, undecyl, and dodecyl groups; C6-20 aryl groups, such as phenyl, tolyl, xylyl, and naphthyl groups; C7-20 aralkyl groups, such as benzyl, phenethyl, and phenylpropyl groups; and any of these groups in which some or all of the hydrogen atoms are substituted with halogen atoms, such as fluorine, chlorine, or bromine atoms.

[0074] The above reaction is carried out at room temperature or under heat in an alcohol, such as methanol, ethanol, isopropanol, or butanol; an aromatic hydrocarbon, such as toluene or xylene; an aliphatic hydrocarbon, such as hexane or heptane; or an organic solvent, such as mineral spirits, ligroin, or petroleum ether. The resulting reaction product is preferably treated as required by distilling off organic solvents or low-boiling components or by filtering off sediments. A dialkylformamide, hexaalkylphosphoamide, or the like may also be added to facilitate the reaction. The cerium content of the resulting cerium-containing organopolysiloxane is preferably in the range of 0.1 to 15% by weight.

[0075] The content of component (D) is not particularly limited, but is an amount at which the content of cerium atoms in the cerium-containing organopolysiloxane (D) is preferably in the range of 1 to 100 ppm and more preferably in the range of 2 to 50 ppm with respect to the total mass of all organopolysiloxane components in the present composition. (E)-Hardening catalyst

[0076] The curing catalyst of component (E) is a curing catalyst for the hydrosilylation reaction, which is a catalyst for promoting the curing of the curable silicone composition of the present invention. Examples of component (E) include platinum-based catalysts, such as chloroplatinic acid, alcoholic solutions of chloroplatinic acid, platinum-olefin complexes, platinum-and-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complexes, and platinum-bearing powders; palladium-based catalysts, such as tetrakis(triphenylphosphine)palladium and mixtures of triphenylphosphine and palladium black; and rhodium-based catalysts; however, platinum-based catalysts are particularly preferred.

[0077] Component (E) is mixed in a catalytic quantity; if a platinum-based catalyst is used as component (E), the amount of platinum atoms is more precisely preferably 0.01 ppm or more, more preferably 0.1 ppm or more and more preferably 1 ppm or more with respect to the total mass of the curable silicone composition of the present invention, and the amount of platinum atoms can also preferably be 20 ppm or less, more preferably 15 ppm or less, more preferably 10 ppm or less and particularly preferably 5 ppm or less, with respect to the total mass of the curable silicone composition of the present invention. (Other organopolysiloxane components)

[0078] The curable silicone composition according to the present invention may comprise organopolysiloxanes containing epoxide groups as organopolysiloxane components other than components (A) and (B). Organopolysiloxanes containing epoxide groups preferably contain at least one epoxide group and at least two alkenyl groups per molecule. Organopolysiloxanes containing epoxide groups may act as tackifiers.

[0079] Examples of the molecular structure of organopolysiloxanes containing epoxy groups are linear, slightly branched, resinous, cyclic, and 3D network structures, with resinous organopolysiloxanes containing epoxy groups being preferred. The curable silicone composition according to the present invention can comprise an organopolysiloxane containing epoxy groups, or it can comprise combinations of at least two organopolysiloxanes containing epoxy groups.

[0080] Organopolysiloxanes containing epoxide groups may preferably contain alkenyl groups, such as C2-12-alkenyl groups, such as vinyl, allyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, undecenyl, and dodecenyl groups, preferably vinyl groups, and may also contain organic groups containing epoxide groups, such as: glycidoxyalkyl groups, such as 2-glycidoxyethyl, 3-glycidoxypropyl, and 4-glycidoxybutyl groups; epoxycyclohexylalkyl groups, such as 2-3,4-epoxycyclohexylethyl and 3-3,4-epoxycyclohexylpropyl groups; and epoxyalkyl groups, such as 3,4-epoxybutyl and 7,8-epoxyoctyl groups; glycidoxyalkyl groups are preferred and 3-glycidoxypropyl groups are particularly preferred.

[0081] Examples of organic groups bonded to a silicon atom other than alkenyl groups and epoxide groups in organopolysiloxanes containing epoxide groups include other, optionally halogen-substituted, monovalent hydrocarbon groups than alkenyl groups and epoxide groups, such as: C1-12 alkyl groups, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, cyclohexyl, heptyl, octyl, nonyl, decyl, undecyl, and dodecyl groups; C6-20 aryl groups, such as phenyl, tolyl, xylyl, and naphthyl groups; C7-20 aralkyl groups, such as benzyl, phenethyl, and phenylpropyl groups; and each of these groups in which some or all of the hydrogen atoms are substituted with halogen atoms, such as fluorine, chlorine and bromine atoms; C1-12 alkyl groups are preferred, especially methyl groups.

[0080] Organopolysiloxanes containing resinous epoxide groups are preferably represented by the following average unit formula (III):. (R 3 3SiO 1 / 2 ) f (R 3 2SiO 2 / 2 ) g (R 3 SiO 3 / 2 ) h (SiO 4 / 2 ) i (XO 1 / 2 ) j {in formula (III) are R 3 each independent, optionally halogen-substituted, monovalent hydrocarbon groups, except that at least two R 3 alkenyl groups and at least one R 3 an organic group containing epoxide groups, X is a hydrogen atom or an alkyl group, 0 ≤ f < 1, 0 < g < 1, 0 ≤ h < 0.9, 0 ≤ i < 0.5, 0 ≤ j < 0.4, f + g + h + i = 1.0 and h + i > 0. The symbol j represents the number of (X0) groups when the total number of silicon atoms is 1 (ratio of the number of (X0) groups to the total number of silicon atoms).

[0082] In the formula (IV) above, examples of monovalent hydrocarbon groups, optionally halogen-substituted, are represented by R. 3 The alkenyl groups mentioned above, organic groups containing epoxide groups, and other monovalent hydrocarbon groups are represented. In formula (III) above, X is a hydrogen atom or an alkyl group. Preferred examples of alkyl groups represented by X include Cl-3 alkyl groups, in particular methyl, ethyl, and propyl groups.

[0083] In formula (III) above, f is preferably in the range of 0 ≤ f ≤ 0.5, particularly preferably in the range of 0 ≤ f ≤ 0.3, and even more preferably in the range of 0 ≤ f ≤ 0.1. In formula (III) above, g is preferably in the range of 0.1 ≤ g ≤ 0.7, particularly preferably in the range of 0.2 ≤ g ≤ 0.6, and especially in the range of 0.3 ≤ g ≤ 0.5. In formula (III) above, h is preferably in the range of 0.2 ≤ h ≤ 0.8, particularly preferably in the range of 0.3 ≤ h ≤ 0.7, and especially in the range of 0.4 ≤ h ≤ 0.65. In formula (III) above, i is preferably in the range of 0 ≤ i ≤ 0.4, particularly preferably in the range of 0 ≤ i ≤ 0.25 and especially in the range of 0 ≤ i ≤ 0.1. In formula (III) above, j is preferably in the range of 0 ≤ j ≤ 0.3, particularly preferably in the range of 0 ≤ j ≤ 0.2 and especially in the range of 0 ≤ j ≤ 0.1.

[0084] In a preferred embodiment of the present invention, organopolysiloxanes containing resinous epoxy groups are such that h in the above formula (III) is greater than 0, and in particular contain siloxane units connected by SiO 3 / 2 (T units) are represented. The resinous epoxy group-containing organopolysiloxanes can be siloxane units linked by SiO₂. 4 / 2 (Q units) are represented, or none, and preferably none. The resinous epoxy group-containing organopolysiloxanes can be siloxane units linked by SiO₂. 1 / 2 (M units) are represented, or none, and preferably none.

[0085] In a preferred embodiment of the present invention, organopolysiloxanes containing epoxide groups have organic groups containing epoxide groups in the form of molecular side-chain side groups. Organopolysiloxanes containing epoxide groups preferably have organic groups containing epoxide groups in siloxane units (T-units) connected by SiO₂. 3 / 2 be reproduced.

[0086] In a preferred embodiment, the amount of alkenyl groups in all organopolysiloxanes containing epoxide groups and bound to a silicon atom is not particularly limited, but is preferably 1 mol% or more, more preferably 3 mol% or more and more preferably 5 mol% or more, and is for example 30 mol% or less, preferably 20 mol% or less and more preferably 15 mol% or less.

[0087] The amount of epoxide-containing organic groups in all organic groups bonded to a silicon atom in epoxide-containing organopolysiloxanes is not particularly limited, but is preferably 5 mol% or more, more preferably 10 mol% or more, and even more preferably 20 mol% or more, and is, for example, 60 mol% or less, and preferably 50 mol% or less. The amount of epoxide-containing organic groups can be determined, for example, by analysis such as Fourier-transform infrared spectroscopy (FT-IR) or nuclear magnetic resonance (NMR).

[0088] The mass-averaged molecular mass (Mw) of organopolysiloxanes containing epoxide groups is not particularly limited, but can range from 1,000 to 10,000. As used in this description, the mass-averaged molecular mass can be determined by GPC.

[0089] The content of organopolysiloxanes containing epoxy groups is not particularly limited, but may preferably be 0.01 wt% or more, more preferably 0.1 wt% or more and particularly preferably 0.5 wt% or more, based on the total mass of the curable silicone composition of the present invention, and may also be an amount of 20 wt% or less, more preferably 10 wt% or less and particularly preferably 5 wt% or less, based on the total mass of the curable silicone composition of the present invention.

[0090] The curable silicone composition may contain, as another organopolysiloxane component, a cyclic organopolysiloxane with at least two alkenyl groups per molecule as a silicone-reactive diluent. Such a cyclic organopolysiloxane may preferably be represented by average structural formula (IV): (R 4 2SiO) n(in formula (IV) are R 4 the same or different, possibly halogen-substituted, monovalent hydrocarbon groups, except that at least two R 4 per molecule alkenyl groups are and n is 4 to 15, preferably 4 to 10 and particularly preferably 4 to 8.).

[0091] In formula (IV) are the monovalent hydrocarbon groups, which may be halogen-substituted, that are represented by R 4reproduced, preferably selected from: C1-12 alkyl groups, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, cyclohexyl, heptyl, octyl, nonyl, decyl, undecyl and dodecyl groups; C6-20 aryl groups, such as phenyl, tolyl, xylyl and naphthyl groups; C2-12 alkenyl groups, such as vinyl, allyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, undecenyl and dodecenyl groups; and each of these groups in which some or all of the hydrogen atoms are substituted with halogen atoms, such as fluorine, chlorine, and bromine atoms. R 4 are preferably selected from C1-6 alkyl groups and in particular methyl or C2-6 alkenyl groups and in particular vinyl.

[0092] The content of cyclic organopolysiloxanes is not particularly limited, but may preferably be 0.01 wt% or more, more preferably 0.1 wt% or more and particularly preferably 0.5 wt% or more, based on the total mass of the curable silicone composition of the present invention, and may also be 20 wt% or less, more preferably 10 wt% or less and particularly preferably 5 wt% or less, based on the total mass of the curable silicone composition of the present invention. (Other components)

[0093] Optional components may be mixed with the curable silicone composition of the present invention, provided that the objectives of the present invention are not thereby impaired. Examples of optional components include acetylene compounds, organophosphorus compounds, siloxane compounds containing vinyl groups; other inorganic fillers as component (C), such as quartz flour, silicon dioxide, magnesium carbonate, diatomaceous earth, and inorganic fillers obtained by subjecting the surface of such inorganic fillers to a hydrophobic treatment with an organosilicon compound; surface treatment agents, hydrosilylation reaction inhibitors, tackifiers, heat-conferring agents, cold-conferring agents, flame-retardant agents, thixotropic agents, phosphors, and solvents.Such optional components are usually added in an amount of 0.001 to 20% by mass of the total composition present.

[0094] Examples of inorganic fillers include silica fume-forming silica, dry silica, wet silica, crystalline silica, precipitated silica, and the like. Furthermore, the silica can be subjected to a hydrophobic surface treatment using an organosilicon compound, such as an organoalkoxysilane compound, an organochlorosilane compound, an organosilasane compound, a low-molecular-weight siloxane compound, a silane adhesion promoter, a titanate adhesion promoter, or the like.

[0095] Hydrosilylation reaction inhibitors are components used to suppress the hydrosilylation reaction of the curable silicone composition. Examples of such curing reaction inhibitors include: alkyne alcohols, such as 2-methyl-3-butyn-2-ol, 3,5-dimethyl-1-hexyn-3-ol, 2-phenyl-3-butyn-2-ol, 1-ethinyl-1-cyclohexanol, and 1-ethinyl-2-cyclohexanol; enyne compounds, such as 3-methyl-3-penten-1-yne and 3,5-dimethyl-3-hexen-1-yne; and low molecular weight siloxanes containing alkenyl groups, such as tetramethyltetravinylcyclotetrasiloxane and tetramethyltetrahexenylcyclotetrasiloxane. and alkynyloxysilanes, such as methyl-tris-1,1-dimethylpropynyloxysilane, vinyl-tris-1,1-dimethylpropynyloxysilane, and methyl-tris-3-methyl-1-butyn-3-oxysilane. The hydrosilylation reaction inhibitor is preferably selected from alkyne alcohols and is particularly preferably 1-ethinyl-1-cyclohexanol.The reaction inhibitor is usually added in an amount of 0.001 to 5% by mass of the total composition present.

[0096] In one embodiment of the present invention, the curable silicone composition comprises two or more different curing reaction inhibitors. In a preferred embodiment, the curable silicone composition comprises a combination of at least one alkyne alcohol and at least one alkynyloxysilane as a curing reaction inhibitor.

[0097] The surface treatment agent is a surface treatment agent for a filler, in particular for the thermally conductive filler of component (C), the type of which is not particularly limited, but examples include organosilasanes, organocyclosiloxanes, organochlorosilanes, organoalkoxysilanes, organopolysiloxanes containing alkoxysilylalkyl groups, low molecular weight linear siloxanes and organic compounds, where examples of organic compounds include polyhydric alcohols, alkanolamines or derivatives thereof, organosilicon compounds such as organic siloxane, higher fatty acids or metal salts thereof, organometallic compounds, organometallic complexes, fluorine-based organic compounds, anionic surfactants, cationic surfactants and nonionic surfactants.

[0098] Organopolysiloxanes containing alkoxysilylalkyl groups, which serve as surface treatment agents, can be represented, for example, by the following formula: (R a O)3Si-(CH2)p-(R b 2SiO) q -R c (in the formula R a and R b each independently a Cl-4 alkyl group and in particular methyl, R c is a Cl-10 alkyl group and preferably a C2-6 alkyl group, p is 3 to 12 and preferably 4 to 10, and q is 50 to 150 and preferably 75 to 95).

[0099] The content of surface treatment agents is not particularly limited, but may usually be 0.01% by mass or more, preferably 0.05% by mass or more, based on the total mass of the curable silicone composition of the present invention, and may also be an amount of 10% by mass or less, preferably 5% by mass or less, based on the total mass of the curable silicone composition of the present invention.

[0100] In a preferred embodiment of the present invention, the curable silicone composition can be cured to form a cured product with improved thermal conductivity. In a preferred embodiment, for example, the thermal conductivity of a cured product of the curable silicone composition is 0.5 W / (m·K) or more, and preferably 1.0 W / (m·K) or more. The upper limit of the thermal conductivity is not particularly restricted, but is usually less than 3.0 W / (m·K). The thermal conductivity can be determined, for example, using a hot disk.

[0101] The curable silicone composition of the present invention can be produced by mixing the various components. The method for mixing the components may be a conventionally known method, but is not particularly limited; for example, the composition can be produced using a mixing device. Examples of such mixing devices include, but are not limited to, continuous single- and twin-screw mixers, twin-roller mixers, Ross mixers, Hobart mixers, dental mixers, planetary mixers, kneading mixers, and Henschel mixers. [Adhesive]

[0102] The present invention also relates to an adhesive consisting of the curable silicone composition of the present invention. The adhesive according to the present invention can preferably be used as a thermally conductive adhesive. The adhesive according to the present invention can preferably be used as an adhesive for bonding chips, such as optical semiconductor elements. The configuration of the adhesive of the present invention is not particularly limited, but is preferably in the form of a film. Examples of semiconductors that can be bonded with the adhesive of the present invention include semiconductors made of SiC or GaN, particularly optical semiconductors, such as power semiconductors or light-emitting diodes, but are not specifically limited to these. [Optical semiconductor device]

[0103] The present invention also relates to an optical semiconductor device containing the adhesive of the present invention. Examples of optical semiconductor elements in optical semiconductor devices include light-emitting diodes (LEDs), semiconductor lasers, photodiodes, phototransistors, and light emitters and light receivers for semiconductor imaging and for optocouplers, with light-emitting diodes (LEDs) being particularly preferred.

[0104] Since light is emitted from the top, bottom, left, and right sides of optical semiconductor elements in light-emitting diodes (LEDs), the components used to construct the LED should be non-absorbing and made of materials with high light transmittance or high reflectivity. Therefore, substrates on which optical semiconductor elements are mounted should also be made of materials with high light transmittance or high reflectivity.Examples of substrates on which optical semiconductor elements are mounted include: conductive metals, such as silver, gold, and copper; non-conductive metals, such as aluminum and nickel; thermoplastic resins mixed with white pigments, such as PPA and LCP; thermosetting resins containing white pigments, such as epoxy resins, BT resins, polyimide resins, and silicone resins; and ceramics, such as aluminum oxide and aluminum nitride.

[0105] Specific embodiments of the present invention are shown below.

[0106] Embodiment 1: A curable silicone composition comprising the following: (A) an organopolysiloxane containing alkenyl groups with at least two alkenyl groups per molecule; (B) an organohydrogen polysiloxane with at least two hydrogen atoms bonded to silicon atoms per molecule; (C) a thermally conductive filler in an amount of 5% by mass or more, based on the total mass of the composition; (D) a cerium-containing organopolysiloxane; and (E) a hardening catalyst.

[0107] Embodiment 2: The curable silicone composition according to embodiment 1, wherein the (A) alkenyl group-containing organopolysiloxane further comprises an MQ resin.

[0108] Embodiment 3: The curable silicone composition according to embodiment 1 or 2, wherein the (C) thermally conductive filler is a metal oxide.

[0109] Embodiment 4: The curable silicone composition according to any one of embodiments 1 to 3, wherein the (C) thermally conductive filler comprises two thermally conductive fillers with different average particle sizes. Embodiment 5: The curable silicone composition according to any one of embodiments 1 to 4, wherein the cerium content of the (D) cerium-containing organopolysiloxane is 1 to 100 ppm, based on the total mass of all organopolysiloxane components in the composition.

[0110] Embodiment 6: An adhesive consisting of the curable silicone composition according to one of embodiments 1 to 5.

[0111] Embodiment 7: An optical semiconductor device comprising the adhesive according to embodiment 6. [Examples]

[0112] The curable silicone composition of the present invention is described in more detail by means of the following examples and comparative examples.

[0113] Curable silicone compositions were prepared by mixing the components in the formulations (by weight) shown in the tables. Hereinafter, Me denotes methyl groups, Vi denotes vinyl groups, and Ep denotes 3-glycidoxypropyl groups. The structures of the organopolysiloxane components are also shown in a simplified manner in the tables, and the functional groups other than Me in the M, D, or T units are shown in parentheses. H / Vi indicates the molar ratio of hydrogen atoms (H) bonded to silicon atoms to the vinyl groups (Vi) in the organopolysiloxane components. In the description of this application, "unit formula" means a chemical formula containing a siloxane unit, which is represented by (SiO₂). x / 2(x is an integer from 1 to 4), and "structural formula" denotes a chemical formula that does not contain any such siloxane units. The content of component d in the tables indicates the amount of cerium atoms in component d (in ppm) in all organopolysiloxane components.

[0114] -Component a-1: Resin-like organopolysiloxane containing alkenyl groups, described by the average unit formula (Me3SiO 1 / 2 ) 40.9 (ViMe2SiO 1 / 2 ) 7.1 (SiO 4 / 2 ) 52 (OH) 4.9 is reproduced (fixed at 25 °C; mass-averaged molecular mass (Mw): 5100) Component a-2: Organopolysiloxane containing linear alkenyl groups, characterized by the average structural formula ViMe2SiO(M2SiO) 46 SiMe2Vi is represented by component b: Linear organohydrogen polysiloxane, which is represented by the average structural formula Me3SiO(MeHSiO) 50 SiMe3 is played back Component c-1: Aluminum oxide (average particle size: 3.4 µm) Component c-2: Aluminum oxide (average particle size: 0.5 µm) Component d: Cerium-containing dimethylpolysiloxane with a cerium content of 1.4 wt% Component e: Complex of platinum and divinyltetramethyldisiloxane with a platinum concentration of 3.0 wt% Component f-1: 1-ethynyl-2-cyclohexanol Component f-2: Methyl-tris-3-methyl-1-butyne-3-oxysilane Component g: Cyclic alkenyl group-containing organopolysiloxane, represented by the average structural formula (ViMeSiO)4 Component h: Condensation reaction product of 3-glycidoxypropyltrimethoxysilane and methylvinylsiloxane oligomer, terminating both molecular ends with silanol groups (mass-averaged molecular mass (Mw): 1280; viscosity at 25 °C: 22.5 mm) 2 / s) Component i: Pyrogenic silica (surface treated with hexamethyldisilazane and trimethylsilane) Component j: Organopolysiloxane surface treatment agent containing alkoxysilylalkyl groups [Stamp shear strength]

[0115] Aluminum plates measuring 25 mm × 75 mm were used as substrates, and five aluminum chips measuring 5 mm × 5 mm × 1 mm were used as bonding chips. A curable silicone compound (0.0080 g ± 0.0005 g) for each chip was applied to the plates, the chips were arranged on top, and then bonded to the plates by curing at 150 °C for 2 hours. The bond shear strength was determined using a bond tester (model number: SS-30WD; test mode: PH50 press; speed: 0.120 mm / s). The test specimens were also aged for 1000 hours at 200 °C, and the bond shear strength was then determined similarly. The results for the bond shear strength before and after aging are shown below. [Table 1] Components Example 1 Example 2 Example 3 Comparative example 1 Comparative example 2 Comparative example 3 a-1 M 40,9 M(Vi) 7,1 Q 52 (OH) 4,9 9,9 9,9 9,9 9,9 9,9 9,9 a-2 M(We)D 46 M(We) 5,1 5,1 5,1 5,1 5,1 5,1 b MD(H) 50 M 3,35 3,35 3,35 3,35 3,35 3,35 c-1 Al2O3 (D50: 3, 4 µm) 1,8 16,2 55 1,8 16,2 55 c-2 Al2O3 (D50: 0.5 µm) 0,77 6,94 23,89 0,77 6,94 23,89 d (PDMS-0) Ce (ppm) 5 5 5 - - - e Pt catalyst (ppm Pt) 5,0 5,0 5, 0 5,0 5,0 5,0 f-1 0,119 0,119 0,119 0,119 0,119 0,119 f-2 0,037 0,037 0,037 0,037 0,037 0,037 g D(Vi)4 1 1 1 1 1 1 h D(Vi)8D 19 T(Ep)38 1 1 1 1 1 1 i 2 2 2 2 2 2 j 0,5 0,5 0,5 0,5 0, 5 0,5 H / Vi ratio 1,9 1,9 1,9 1,9 1,9 1,9 Al2O3 content (mass %) 10 50 78 10 50 78 Reviews Aging resistance (MPa) before aging 4,82 4,86 7,87 3,27 4,81 8,36 after aging 3,47 6,04 7,42 1,02 1,9 3,38 [Thermal conductivity]

[0116] Curable silicone compounds were cured by holding them at 150 °C and 20 MPa for 15 minutes and at atmospheric pressure for 105 minutes, yielding cylindrical cured samples with a height of 1 cm and a diameter of 2.1 cm. The thermal conductivity (W / (m·K)) of the samples was determined using a hot disk (Hot Disk from Kyoto Electronics Manufacturing Co., Ltd.; model number: TPS 500s). The results are shown in the following tables. [Table 2] Components Example 3 Example 4 a-1 M 40,9 M(Vi) 7,1 Q 52 (OH) 4,9 9,9 9,9 a-2 M(We)D 46 M(We) 5,1 5,1 b MD(H) 50 M 3,35 3,35 0-1 Al2O3 (D50: 3.4 µm) 55 42 c-2 Al2O3 (D50: 0.5 µm) 23,89 18 d (PDMS-0) Ce (ppm) 5 5 e Pt catalyst (ppm Pt) 5,0 5,0 f-1 0,119 0,119 f-2 0,037 0,037 g D(Vi)4 1 1 h D(Vi)8D 19 T(Ep) 38 1 1 i 2 2 j 0,5 0,5 SH / Vi 1,9 1,9 A2O3 content (mass %) 78 72 Reviews Thermal conductivity (W / (m·K)) 1,4 1,0 [Mass loss]

[0117] Curable silicone compounds were cured by holding them at 150 °C and 20 MPa for 15 minutes and at atmospheric pressure for 105 minutes, yielding cured foil samples measuring 1 cm × 5 cm × 2 mm. The samples were aged at 200 °C and weighed after 500 hours and 1000 hours, and the mass loss (%) was calculated using the following formula. (Initial mass - mass after aging) / Initial mass × 100 [Table 3] Components Example 3 Example 5 Example 6 Comparative example 4 a-1 M 40,9 M(Vi) 7,1 Q 52 (OH) 4,9 9,9 9,9 9,9 9,9 a-2 M(We)D 46 M(We)) 5,1 5,1 5,1 5,1 b MD(H) 50 M 3,35 3,35 3,35 3,35 c-1 Al2O3 (D50: 3.4 µm) 55 55 55 55 c-2 Al2O3 (D50: 0.5 µm) 23,89 23,89 23,89 23,89 d (PDMS-0) Ce (ppm) 5 2 10 - e Pt catalyst (ppm Pt) 5,0 5,0 5,0 5,0 f-1 0,119 0,119 0,119 0,119 f-2 0,037 0,037 0,037 0,037 g D(Vi)4 1 1 1 1 h D(Vi)8D 19 T(Ep) 38 1 1 1 1 i 2 2 2 2 j 0,5 0,5 0,5 0,5 SH / Vi 1,9 1,9 1,9 1,9 A2O3 content (mass %) 78 78 78 78 Reviews Mass loss (%) 500 stunces 0,73 0,82 0,81 1,3 1000 hours 0,99 1,02 1,02 1,56

[0118] As the results in Table 1 show, the curable silicone composition comprising the thermally conductive filler of the present invention retained exceptional strength and exhibited exceptional thermal stability even after aging at elevated temperatures. As the results in Table 2 also show, the curable silicone composition according to the present invention with a high content of thermally conductive filler exhibited high thermal conductivity. As the results in Table 3 further show, the curable silicone composition according to the present invention exhibited a low weight loss of approximately 1% even after 1000 hours of aging at elevated temperatures, and the chemical structure was preserved even after aging.

[0119] Preferred examples of the present invention have been described above, but the present invention is not limited to these examples. Additions, omissions, substitutions, and other modifications to the composition are possible within the scope of protection of the present invention. The present invention is not limited by the preceding description and only by the appended claims. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] JP 2016-513165

[0007] JP 2021-88678

[0007]

Claims

[1] Curable silicone composition comprising the following: (A) an organopolysiloxane containing alkenyl groups with at least two alkenyl groups per molecule; (B) an organohydrogen polysiloxane with at least two hydrogen atoms bonded to silicon atoms per molecule; (C) a thermally conductive filler in an amount of 5% by mass or more, based on the total mass of the composition; (D) a cerium-containing organopolysiloxane; and (E) a hardening catalyst. [2] Curable silicone composition according to claim 1, wherein the (A) alkenyl group-containing organopolysiloxane comprises an MQ resin. [3] Curable silicone composition according to claim 1 or 2, wherein the (C) thermally conductive filler is a metal oxide. [4] Curable silicone composition according to claim 1, wherein the (C) thermally conductive filler comprises two thermally conductive fillers with different mean particle sizes. [5] Curable silicone composition according to claim 1, wherein the content of cerium atoms of the (D) cerium-containing organopolysiloxane is 1 to 100 ppm, based on the total mass of all organopolysiloxane components in the composition. [6] Adhesive comprising the curable silicone composition according to any one of claims 1 to 5. [7] Optical semiconductor device comprising the adhesive according to claim 6.