End-modified organopolysiloxane and its manufacturing method, surface treatment agent, and silicone composition

Abstract

To provide a wetter (surface treatment agent) that enables the incorporation of a filler into a silicone composition to a high degree, and yields a composition which, even after long-term storage, exhibits little change in viscosity.SOLUTION: The present invention pertains to: a one-end-modified organopolysiloxane represented by general formula (1); and a silicone composition comprising the one-end-modified organpolysiloxane and a filler. (In the formula, R1's are each independently a C1-20 monovalent hydrocarbon group that may have a substituent, R2's are each independently a C1-20 alkyl group that may have a substituent or a C3-20 cycloalkyl group that may have a substituent, a is an integer of 1-3, and n is a number of 1-300).SELECTED DRAWING: None

Description

[Technical Field]

[0001] This invention relates to a single-ended modified organopolysiloxane, particularly a linear organopolysiloxane having an alkoxysilyl-vinylene group at one end, a method for producing the same, a surface treatment agent, and a silicone composition. [Background technology]

[0002] Many electronic components generate heat during use, and therefore, heat dissipation is necessary for these components to function properly. In particular, integrated circuit elements such as CPUs and GPUs used in personal computers and smartphones continue to generate increasing heat due to higher operating frequencies and miniaturization of packages, making heat countermeasures and design crucial issues. Furthermore, with the recent advancement of electric vehicles, many electronic components are used, and these components may be used under more severe conditions, such as high temperature and high humidity environments.

[0003] Many methods have been proposed to remove this heat. In particular, for electronic components that generate a large amount of heat, a method has been proposed to dissipate heat by interposing a thermally conductive material such as thermally conductive grease or thermally conductive sheet between the electronic component and a heat sink or other material. Thermally conductive grease is particularly suitable for use because it is amorphous and exhibits high thermal conductivity by adhering to the substrate after curing. As such a thermally conductive material, a heat dissipation adhesive based on silicone and blended with zinc oxide, aluminum, or alumina powder is known (Patent Document 1).

[0004] To create a highly thermally conductive material based on silicone, it is necessary to fill it with a high concentration of thermally conductive filler. However, simply attempting to fill it with a high concentration significantly reduces the fluidity of the thermally conductive material, resulting in poor workability such as application (dispensing and screen printing), and furthermore, the inability to conform to the fine irregularities on the surface of electronic components and heat sinks. Therefore, to solve this problem, a method has been proposed in which the thermally conductive filler is surface-treated with a wetter and dispersed in the base polymer, silicone, in order to maintain the fluidity of the thermally conductive material. Currently, commonly used wetters include polydimethylsiloxanes containing hydrolyzable groups and oligosiloxanes containing hydrolyzable groups (Patent Documents 2 and 3). While these wetters provide good fluidity, challenges remain in suppressing viscosity increases during long-term storage (deterioration of discharge performance due to increased viscosity) and hardness increases due to prolonged exposure to high-temperature environments, as unreacted hydrolyzable groups present in the material react with the material. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Patent No. 3952184 [Patent Document 2] Patent No. 3543663 [Patent Document 3] Patent No. 4727017 [Overview of the project] [Problems that the invention aims to solve]

[0006] Therefore, the present invention aims to provide a wetter (surface treatment agent) that enables high-density filling of a silicone composition with filler and provides a composition that exhibits minimal viscosity changes even after long-term storage. Furthermore, the present invention aims to provide a wetter that, when added to an addition-curing type silicone composition, can suppress the increase in hardness of the resulting cured product when exposed to high-temperature environments for extended periods. [Means for Solving the Problems]

[0007] As a result of intensive studies to achieve the above object, the present inventors have found that a linear organopolysiloxane modified with a structure having an alkoxysilyl-vinylylene group at one end acts as a wetter useful for solving the above-described problems, and have completed the present invention.

[0008] That is, the present invention provides the following one-end modified organopolysiloxane and the like. [1] One-end modified organopolysiloxane represented by the following general formula (1). [Chemical formula] (In the formula, R 1 is, independently of each other, a monovalent hydrocarbon group having 1 to 20 carbon atoms which may have a substituent, and R 2 is, independently of each other, an alkyl group having 1 to 20 carbon atoms which may have a substituent or a cycloalkyl group having 3 to 20 carbon atoms which may have a substituent. a is an integer of 1 to 3. n is a number of 1 to 300.) [2] A method for producing one-end modified organopolysiloxane represented by the following general formula (1), which comprises a step of subjecting a bissilane compound represented by the following general formula (2) and an organohydrogenpolysiloxane represented by the following general formula (3) to a hydrosilylation reaction. [Chemical formula] (In the formula, R 1 is, independently of each other, a monovalent hydrocarbon group having 1 to 20 carbon atoms which may have a substituent, and R 2 is, independently of each other, an alkyl group having 1 to 20 carbon atoms which may have a substituent or a cycloalkyl group having 3 to 20 carbon atoms which may have a substituent. a is an integer of 1 to 3. n is a number of 1 to 300.) [3] A surface treatment agent for powder comprising the one-end modified organopolysiloxane according to [1]. [4] (A) A terminally modified organopolysiloxane represented by the following general formula (1), [ka] (In the formula, R 1 These are, independently of each other, monovalent hydrocarbon groups having 1 to 20 carbon atoms, which may have substituents, and R 2 These are, independently of each other, C1 to C20 alkyl groups that may have substituents, or C3 to C20 cycloalkyl groups that may have substituents. a is an integer from 1 to 3. n is a number from 1 to 300. And, (B) Filler A silicone composition containing the following: [5] The silicone composition according to [4], wherein the average particle size of component (B) is 0.01 to 150 μm. [6] moreover, (C) A molecule having at least two aliphatic unsaturated hydrocarbon groups bonded to silicon atoms, with a kinematic viscosity of 60-100,000 mm² at 25°C. 2 / s organopolysiloxane, (D) Organohydrogenpolysiloxane having two or more hydrogen atoms bonded to silicon atoms in one molecule: an amount such that the number of hydrogen atoms bonded to silicon atoms relative to the total number of aliphatic unsaturated hydrocarbon groups in component (A) and component (C) is 0.5 to 5. Furthermore, (E) Platinum group metal catalyst The silicone composition according to [4] or [5], comprising: [7] Furthermore, the silicone composition according to [6] further comprises (F) one or more addition reaction control agents selected from the group consisting of acetylene compounds, nitrogen compounds, organophosphorus compounds, oxime compounds and organochloro compounds. [8] Furthermore, the silicone composition according to any one of the following [4] to [7], further comprising (G) a hydrolyzable organopolysiloxane represented by the following general formula (W) in an amount of 0.1 to 20% by mass relative to the whole composition. [Chemical formula] (In the formula, R 3 is, independently of each other, a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms which may have a substituent, and R 4 is, independently of each other, an alkyl group having 1 to 20 carbon atoms which may have a substituent or a cycloalkyl group having 3 to 20 carbon atoms which may have a substituent. b is an integer from 1 to 3. m is a number from 1 to 200.) [9] The silicone composition according to any one of [4] to [8], wherein the filler of component (B) is a thermally conductive filler. [Advantages of the Invention]

[0009] The one-end modified organopolysiloxane of the present invention has an alkoxysilyl-vinylene group (alkoxysilyl-ethenylene group) excellent in reactivity with a filler, and thus is useful as a wetting agent (surface treatment agent) for highly filling a filler in a silicone composition, and can provide a silicone composition with little viscosity change even after long-term storage. Furthermore, when the one-end modified organopolysiloxane of the present invention is added as a wetting agent for a thermally conductive filler to an addition-curable silicone composition, the resulting cured product can suppress an increase in hardness when exposed to a high-temperature environment for a long time, and thus can provide a highly reliable heat dissipation material suitable for electronic component packages and power modules. [Modes for Carrying Out the Invention]

[0010] Hereinafter, the present invention will be described in more detail. [One-end modified organopolysiloxane] The one-end modified organopolysiloxane of the present invention is a linear organopolysiloxane modified with a structure having an alkoxysilyl-vinylene group at one end, represented by the following general formula (1).

[0011] [Chemical formula] (In the formula, R 1 These are, independently of each other, monovalent hydrocarbon groups having 1 to 20 carbon atoms, which may have substituents, and R 2 These are, independently of each other, C1 to C20 alkyl groups or C3 to C20 cycloalkyl groups that may have substituents. a is an integer from 1 to 3. n is a number from 1 to 300.

[0012] Here, in the above general formula (1), R 1 The substituted or unsubstituted monovalent hydrocarbon groups having 1 to 20 carbon atoms may be the same or different alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, and eicosyl groups; cyclopentyl, cyclohexyl Examples of these groups include cycloalkyl groups such as xyl groups; alkenyl groups such as vinyl groups, allyl groups, butenyl groups, pentenyl groups, and hexenyl groups; aryl groups such as phenyl groups, tolyl groups, xylyl groups, and α-,β-naphthyl groups; aralkyl groups such as benzyl groups, 2-phenylethyl groups, and 3-phenylpropyl groups; and groups in which some or all of the hydrogen atoms of these groups are substituted with halogen atoms such as F, Cl, Br, or cyano groups, such as 3-chloropropyl groups, 3,3,3-trifluoropropyl groups, and 2-cyanoethyl groups. Among these, monovalent hydrocarbon groups having 1 to 10 carbon atoms, particularly 1 to 6 carbon atoms, are preferred, with methyl groups, ethyl groups, and phenyl groups being more preferred, and methyl groups and phenyl groups being even more preferred in terms of availability, productivity, and cost.

[0013] R 2Examples of C1 to C20 alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, and eicosyl groups. Examples of cycloalkyl groups include cyclopentyl and cyclohexyl groups. Examples of C1 to C20 alkyl groups that may have substituents include aralkyl groups such as benzyl, 2-phenylethyl, and 3-phenylpropyl. Furthermore, some or all of the hydrogen atoms of these (substituted) alkyl groups may be substituted with halogen atoms such as F, Cl, Br, or cyano groups, for example, 3-chloropropyl group, 3,3,3-trifluoropropyl group, 2-cyanoethyl group, etc. 2 Among these, alkyl groups having 1 to 6 carbon atoms, particularly 1 to 4 carbon atoms, are preferred, with methyl and ethyl groups being more preferred, and methyl groups being even more preferred in terms of availability, productivity, and cost.

[0014] a is an integer from 1 to 3, but is preferably 2 or 3, and more preferably 3.

[0015] n is a number between 1 and 300, preferably between 10 and 250, and more preferably between 30 and 200. If n is less than 1, reliability may be reduced because the end-modified organopolysiloxane is more likely to bleed out, and if n is greater than 300, the wettability of the filler may become insufficient, or the viscosity of the composition may increase, resulting in poor fluidity.

[0016] Specific examples of the one-ended modified organopolysiloxane represented by the general formula (1) of the present invention include, for example, those represented by the following structural formula.

[0017] [ka]

[0018] <Method for producing terminally modified organopolysiloxanes> The one-ended modified organopolysiloxane of the present invention can be produced, for example, by hydrosilylation a bissilane compound (2) obtained by a hydrosilylation reaction (reaction formula [1] below) between a silane having two ethynyl groups on the same silicon atom (diethynyldiorganosilane) and an alkoxyhydrogensilane, and a linear organopolysiloxane (3) having a SiH group at one end (reaction formula [2] below).

[0019] [ka] (In the formula, R 1 , R 2 (a and n are as described above.)

[0020] [ka] (In the formula, R 1 , R 2 (a and n are as described above.)

[0021] Suitable catalysts for the hydrosilylation reaction described above include platinum group metal catalysts, such as platinum, palladium, rhodium, and ruthenium-based catalysts, with platinum-based catalysts being particularly preferred. Specific examples include solid platinum supported on a support such as platinum black, alumina, or silica; chloroplatinic acid; alcohol-modified chloroplatinic acid; and complexes of chloroplatinic acid with olefins or vinylsiloxanes. Platinum group metal catalysts may be used individually or in combination of two or more. The amount of these catalysts used can be a so-called catalytic amount; for example, relative to an alkoxyhydrogensilane or bissilane compound, it can be used in amounts of 0.1 to 1,000 ppm by mass, particularly 0.5 to 100 ppm by mass, in terms of platinum group metal.

[0022] The above hydrosilylation reaction can be carried out according to conventional methods, preferably at a temperature of 50 to 120°C, particularly 60 to 100°C, for 0.5 to 12 hours, especially 1 to 6 hours. It can be carried out without a solvent, but organic solvents such as hexane, octane, toluene, and xylene may be used if necessary. Furthermore, in reaction formula [1], since 1 mole of alkoxyhydrogensilane is reacted with 1 mole of diethynyldiorganosilane, it is preferable to mix an excess amount of diethynyldiorganosilane with the alkoxyhydrogensilane and carry out the hydrosilylation reaction, and it is preferable that the reaction occurs in a molar ratio of diethynyldiorganosilane:alkoxyhydrogensilane = 9:2 to 3:2, and more preferably in a molar ratio of 4:1 to 2:1. Furthermore, in reaction formula [2], it is preferable that the bissilane compound represented by formula (2) reacts with a linear organopolysiloxane having a SiH group at one end, represented by formula (3), in a 1:1 molar ratio.

[0023] In addition reactions to the ethynyl group, for example, geometric isomers represented by the following reaction formula [3] are produced. Of these, the formation of the E-isomer (trans isomer) is highly selective and also highly reactive. Since this does not affect the properties of the resulting bissilane compound, these geometric isomers can be used without separation in the present invention.

[0024] [ka] (In the formula, R 1 , R 2 (a and n are as described above.) The above hydrosilylation reaction can produce a bissilane compound represented by formula (2) or a one-end modified organopolysiloxane represented by general formula (1). After the hydrosilylation reaction, purification may be carried out according to conventional methods as appropriate.

[0025] The end-modified organopolysiloxane of the present invention is useful as a surface treatment agent (wetter) for powders such as fillers, particularly thermally conductive fillers.

[0026] [Silicone composition] Furthermore, in the present invention, (A) a single-ended modified organopolysiloxane represented by the following general formula (1) [ka] (In the formula, R 1 These are, independently of each other, monovalent hydrocarbon groups having 1 to 20 carbon atoms, which may have substituents, and R 2 These are, independently of each other, C1 to C20 alkyl groups or C3 to C20 cycloalkyl groups that may have substituents. a is an integer from 1 to 3. n is a number from 1 to 300. And, (B) Filler A silicone composition containing the above is provided.

[0027] <(A) component> Component (A) in the silicone composition of the present invention is a one-ended modified organopolysiloxane represented by the general formula (1) described above.

[0028] The amount of component (A) is preferably in the range of 0.1 to 20% by mass, more preferably 0.5 to 15% by mass, and even more preferably 1 to 10% by mass, relative to the total composition. Within this range, sufficient wettability can be provided to the filler, and bleeding of this component from the composition can be suppressed.

[0029] <(B) component> (B) As the filler for component (B), known materials can be used, for example, metals such as aluminum, silver, copper, and metallic silicon; metal oxides such as alumina, zinc oxide, magnesium oxide, beryllium oxide, aluminum oxide, titanium oxide, chromium oxide, cerium oxide, and iron oxide; silica-based fillers such as fumed silica (fumed silica or dry silica), fused silica, settling silica (wet silica), quartz powder (crystalline silica), and silica whose surface has been hydrophobized with an organosilicon compound; glass-based fillers such as glass fibers, glass beads, and glass balloons. Examples of fillers include metal carbonates such as calcium carbonate, magnesium carbonate, and zinc carbonate; metal hydroxides such as aluminum hydride and cerium hydride; metal nitrides such as aluminum nitride and boron nitride; metal carbides such as boron carbide and silicon carbide; allotropes of carbon such as diamond, graphite, carbon nanotubes, graphene, and carbon black; mineral-based fillers such as diatomaceous earth, talc, mica, zeolite, and bentonite; and synthetic resin powders such as polystyrene, polyvinyl chloride, and polypropylene. One type or a mixture of two or more types may be used. (B) By using a highly thermally conductive filler as the filler for component (B), the silicone composition of the present invention becomes a highly thermally conductive silicone composition capable of filling with a high amount of thermally conductive filler, exhibiting excellent workability such as applicability and fluidity, and can be suitably used as a heat dissipation material with excellent stability due to minimal viscosity change after long-term storage and long-term high-temperature storage. Examples of thermally conductive fillers include metals, metal oxides, silica-based fillers, metal hydroxides, metal nitrides, metal carbides, and allotropes of carbon. Specifically, examples include aluminum, silver, copper, metallic silicon, alumina, zinc oxide, magnesium oxide, beryllium oxide, aluminum oxide, titanium oxide, chromium oxide, various silicas (silicon dioxide), cerium oxide, iron oxide, aluminum hydride, cerium hydride, aluminum nitride, boron nitride, boron carbide powder, silicon carbide, diamond, graphite, carbon nanotubes, graphene, etc., and one type or a mixture of two or more types may be used.

[0030] The average particle size of component (B) is preferably in the range of 0.01 to 150 μm, and more preferably in the range of 0.1 to 100 μm. If the average particle size is greater than 0.01 μm, the resulting composition will have better spreadability, and if it is less than 150 μm, the thermal resistance of the composition will be reduced and the performance will be improved.

[0031] In this invention, the average particle size can be measured using the Microtrac MT3300EX manufactured by Nikkiso Co., Ltd., and is the volume-based volume-average diameter. The shape of component (B) may be irregular, spherical, or any other shape.

[0032] From the viewpoint of the spreadability of the composition, the amount of component (B) is preferably 100 to 4,000 parts by mass, and more preferably 500 to 3,500 parts by mass, relative to 100 parts by mass of the total of component (A) and component (C) described later. When a thermally conductive filler is used as component (B), the amount of component (B) is also preferably within the above range from the viewpoint of the thermal conductivity of the composition.

[0033] The silicone composition of the present invention can be further made into an addition-curing type silicone composition by including the following components (C), (D), and (E).

[0034] <(C) component> Component (C) has at least two, preferably 2 to 100, more preferably 2 to 50, aliphatic unsaturated hydrocarbon groups bonded to silicon atoms in one molecule, and has a kinematic viscosity of 60 to 100,000 mm at 25°C. 2 It is an organopolysiloxane with the / s property.

[0035] The aliphatic unsaturated hydrocarbon group bonded to the silicon atom is preferably a monovalent hydrocarbon group having an aliphatic unsaturated bond and having 2 to 8 carbon atoms, more preferably 2 to 6 carbon atoms. Examples include alkenyl groups such as vinyl, allyl, propenyl, isopropenyl, butenyl, hexenyl, cyclohexenyl, and octenyl groups, with vinyl being particularly preferred. The aliphatic unsaturated hydrocarbon group may be bonded to either a silicon atom at the end of the molecular chain, a silicon atom in the middle of the molecular chain, or both.

[0036] Examples of organic groups other than aliphatic unsaturated hydrocarbon groups bonded to a silicon atom include unsubstituted or substituted monovalent hydrocarbon groups having 1 to 18 carbon atoms, preferably 1 to 10 carbon atoms, and more preferably 1 to 8 carbon atoms. Examples of such monovalent hydrocarbon groups include alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, cyclohexyl, octyl, nonyl, and decyl groups; aryl groups such as phenyl, tolyl, xylyl, and naphthyl groups; aralkyl groups such as benzyl, phenylethyl, and phenylpropyl groups; or groups in which some or all of the hydrogen atoms of these groups are substituted with halogen atoms such as fluorine, bromine, or chlorine, or cyano groups, such as chloromethyl, chloropropyl, bromoethyl, trifluoropropyl, and cyanoethyl groups, with methyl and phenyl groups being particularly preferred.

[0037] The kinematic viscosity of component (C) at 25°C is 60-100,000 mm². 2 The speed is / s, preferably 100 to 300,000 mm 2 The kinematic viscosity is 60 mm² / s. 2 If the value is less than / s, the physical properties of the silicone composition will deteriorate, and 100,000 mm 2 If the value exceeds / s, the extensibility of the silicone composition may be poor. In this invention, the kinematic viscosity is the value measured at 25°C using an Ostwald viscometer (the same applies hereinafter).

[0038] The molecular structure of component (C) is not particularly limited and includes linear structures, branched structures, partially branched structures, or linear structures having a cyclic structure. Particularly preferred is a linear structure in which the main chain consists of repeating diorganosiloxane units and both ends of the molecular chain are sealed with triorganosiloxy groups. The organopolysiloxane having a linear structure may also have a partially branched or cyclic structure. (C) Component can be used individually or in combination of two or more components.

[0039] <(D) component> Component (D) is an organohydrogenpolysiloxane having two or more hydrogen atoms (SiH groups) bonded to silicon atoms (SiH groups) in one molecule, particularly preferably 2 to 100, and more preferably 2 to 50. The organohydrogenpolysiloxane only needs to be capable of forming a crosslinked structure by addition reactions between the SiH groups in the molecule and the aliphatic unsaturated hydrocarbon groups of components (A) and (C) described above in the presence of a platinum catalyst.

[0040] Organic groups bonded to silicon atoms other than SiH groups include unsubstituted or substituted monovalent hydrocarbon groups other than aliphatic unsaturated hydrocarbon groups. In particular, these are unsubstituted or substituted monovalent hydrocarbon groups having 1 to 12 carbon atoms, preferably 1 to 10 carbon atoms. Examples include alkyl groups such as methyl, ethyl, propyl, butyl, hexyl, and dodecyl groups, aryl groups such as phenyl groups, aralkyl groups such as 2-phenylethyl and 2-phenylpropyl groups, and those in which some or all of the hydrogen atoms are substituted with halogen atoms such as fluorine, bromine, and chlorine, cyano groups, epoxy ring-containing organic groups (glycidyl or glycidyloxy-substituted alkyl groups), such as chloromethyl, chloropropyl, cyanoethyl, 2-glycidoxyethyl, 3-glycidoxypropyl, and 4-glycidoxybutyl groups. Among these, methyl and 3-glycidoxypropyl groups are preferred.

[0041] The kinematic viscosity of component (D) at 25°C is preferably 1 to 1,000 mm². 2 / s, more preferably 10-300mm 2 The kinematic viscosity is 1 mm² / s. 2 If the value is 1 / s or higher, there is no risk of deterioration in the physical properties of the silicone composition, and 1,000 mm 2 If the value is less than or equal to / s, there is no risk of the silicone composition having poor extensibility.

[0042] The molecular structure of component (D) is not particularly limited and includes linear structures, branched structures, cyclic structures, and linear structures having a partially branched or cyclic structure. Linear structures and cyclic structures are preferred. (D) Component can be used individually or in combination of two or more components.

[0043] The amount of component (D) is such that the number of SiH groups in component (D) relative to the total number of aliphatic unsaturated hydrocarbon groups in components (A) and (C) (hereinafter also simply referred to as "amount of component (D)") is 0.5 to 5, preferably 0.7 to 4.5, and more preferably 0.9 to 4. If the amount of component (D) is less than 0.5, the addition reaction may not proceed sufficiently, resulting in insufficient crosslinking and poor curing. If the amount of component (D) is greater than 5, the crosslinking structure may become non-uniform, or the shelf life of the composition may deteriorate significantly.

[0044] <(E) component> Component (E) is a platinum group metal catalyst that promotes the hydrosilylation reaction between the aliphatic unsaturated hydrocarbon group in component (C) and the SiH group in component (D). Examples of platinum group metal catalysts include platinum-based, palladium-based, rhodium-based, and ruthenium-based catalysts, with platinum-based catalysts being particularly preferred. Specific examples include, for instance, solid platinum supported on a support such as platinum black, alumina, or silica; chloroplatinic acid; alcohol-modified chloroplatinic acid; and complexes of chloroplatinic acid with olefins or vinylsiloxanes. The amount of component (E) used can be a so-called catalytic amount, for example, 0.1 to 1,000 ppm by mass, particularly 0.5 to 100 ppm by mass, in terms of platinum group metals, relative to component (C) above.

[0045] In addition to the above components (A) to (E), the silicone composition of the present invention may optionally contain the following further components.

[0046] <(F) component> Component (F) is a reaction control agent that suppresses the progress of the hydrosilylation reaction and can be added to extend the shelf life and pot life. The reaction control agent can be any conventionally known reaction control agent used in addition-curing silicone compositions. Examples of such reaction control agents include acetylene compounds such as acetylene alcohols (e.g., ethynylmethyldecylcarbinol, 1-ethynyl-1-cyclohexanol, 3,5-dimethyl-1-hexyne-3-ol); various nitrogen compounds such as tributylamine, tetramethylethylenediamine, and benzotriazole; organophosphorus compounds such as triphenylphosphine; oxime compounds; and organochloro compounds.

[0047] When component (F) is included, the amount is preferably 0.05 to 5 parts by mass, and more preferably 0.1 to 2 parts by mass, per 100 parts by mass of component (C). If the amount of reaction control agent is less than 0.05 parts by mass, the desired shelf life and pot life may not be obtained, and if it is more than 5 parts by mass, the curability of the silicone composition may decrease. Furthermore, the reaction control agent may be diluted with an organopolysiloxane or toluene, etc., to improve its dispersibility in the silicone composition.

[0048] <(G) component> Component (G) is a hydrolyzable organopolysiloxane represented by the following general formula (w). This component is used to treat the surface of the filler and plays a role in assisting in increasing the filler's density. [ka] (In the formula, R 3These are, independently of each other, a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms which may have substituents, and R 4 These are, independently of each other, an alkyl group having 1 to 20 carbon atoms that may have substituents, or a cycloalkyl group having 3 to 20 carbon atoms that may have substituents. b is an integer from 1 to 3. m is a number from 1 to 200.

[0049] Here, in the above general formula (w), R 3 The substituted or unsubstituted monovalent hydrocarbon groups having 1 to 20 carbon atoms may be the same or different alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, and eicosyl groups; cyclopentyl, cyclohexyl Examples of these groups include cycloalkyl groups such as xyl groups; alkenyl groups such as vinyl groups, allyl groups, butenyl groups, pentenyl groups, and hexenyl groups; aryl groups such as phenyl groups, tolyl groups, xylyl groups, and α-,β-naphthyl groups; aralkyl groups such as benzyl groups, 2-phenylethyl groups, and 3-phenylpropyl groups; and groups in which some or all of the hydrogen atoms of these groups are substituted with halogen atoms such as F, Cl, Br, or cyano groups, such as 3-chloropropyl groups, 3,3,3-trifluoropropyl groups, and 2-cyanoethyl groups. Among these, monovalent hydrocarbon groups having 1 to 10 carbon atoms, particularly 1 to 6 carbon atoms, are preferred, with methyl groups, ethyl groups, and phenyl groups being more preferred, and methyl groups and phenyl groups being even more preferred in terms of availability, productivity, and cost. Each of the following is an integer from 1 to 3, but is preferably 2 or 3, and more preferably 3.

[0050] R 4Examples of C1 to C20 alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, and eicosyl groups. Examples of cycloalkyl groups include cyclopentyl and cyclohexyl groups. Examples of C1 to C20 alkyl groups that may have substituents include aralkyl groups such as benzyl, 2-phenylethyl, and 3-phenylpropyl. Furthermore, some or all of the hydrogen atoms of these (substituted) alkyl groups may be substituted with halogen atoms such as F, Cl, Br, or cyano groups, for example, 3-chloropropyl group, 3,3,3-trifluoropropyl group, 2-cyanoethyl group, etc. 4 Among these, alkyl groups having 1 to 6 carbon atoms, particularly 1 to 4 carbon atoms, are preferred, with methyl and ethyl groups being more preferred, and methyl groups being even more preferred in terms of availability, productivity, and cost.

[0051] m is a number between 1 and 200, preferably between 3 and 100, and more preferably between 5 and 50. If m is less than 1, the component may bleed out more easily, potentially reducing reliability. If m is greater than 200, the viscosity of the composition may increase, leading to poor fluidity.

[0052] (G) When component is included, the amount included is preferably in the range of 0.1 to 20% by mass, more preferably 1 to 15% by mass, and even more preferably 1 to 10% by mass, relative to the total composition, from the viewpoint of wettability of the filler and prevention of bleeding of this component.

[0053] <Other ingredients> The silicone composition of the present invention may contain non-reactive organo(poly)siloxanes such as dimethylpolysiloxane to adjust the strength and viscosity of the composition. Furthermore, hydrolyzable organopolysiloxanes, various modified silicones, and hydrolyzable organosilanes may be added for the purpose of improving the filling properties of the filler or imparting adhesion to the composition. Furthermore, solvents may be added to adjust the viscosity of the composition. Furthermore, conventionally known antioxidants such as 2,6-di-tret-butyl-4-methylphenol may be added as needed to prevent degradation of the silicone composition. Furthermore, dyes, pigments, flame retardants, settling inhibitors, or thixotropic enhancers may be added as needed.

[0054] The method for producing the silicone composition of the present invention is not particularly limited, but one method is to mix the above-mentioned components (A) and (B), and optionally components (C) to (G) and other components, using a mixer such as Trimix, Twinmix, Planetary Mixer (all registered trademarks of Inoue Seisakusho Co., Ltd.), Ultra Mixer (a registered trademark of Mizuho Industries Ltd.), or Hybimix (a registered trademark of Primix Corporation). Mixing may also be done while heating. The heating conditions are not particularly limited, but the temperature is usually 25 to 220°C, preferably 40 to 200°C, and particularly preferably 50 to 180°C, and the time is usually 3 minutes to 24 hours, preferably 5 minutes to 12 hours, and particularly preferably 10 minutes to 6 hours. Degassing may also be performed during heating. In the present invention, it is preferable to preheat and mix components (A) to (C) and (G) at 20 to 220°C, and then mix in components (D) to (F). Degassing may also be performed during mixing.

[0055] The silicone composition of the present invention has an absolute viscosity, measured at 25°C, preferably 10 to 1,000 Pa·s, more preferably 20 to 700 Pa·s, and even more preferably 30 to 500 Pa·s. If the absolute viscosity is 10 Pa·s or higher, it is easy to maintain its shape, the filler does not settle, and there is no risk of poor workability. If the absolute viscosity is 1,000 Pa·s or lower, it is easy to dispense and apply, and there is no risk of poor workability. The above absolute viscosity can be obtained by adjusting the blending amounts of each component described above. The above absolute viscosity can be measured at 25°C using, for example, a Malcolm viscometer (type PC-1T). Furthermore, when a thermally conductive filler is used as the filler for component (B), the silicone composition of the present invention preferably has a thermal conductivity of 0.5 to 20 W / m·K. The thermal conductivity is the value measured at 25°C using the hot disk method. [Examples]

[0056] The present invention will be specifically described below using synthesis examples, examples, and comparative examples, but the present invention is not limited to these.

[0057] [Synthesis Example 1] In a 500 mL four-necked separable flask equipped with a mechanical stirrer, thermometer, and dropping funnel, 90.9 g (0.840 mol) of diethynyldimethylsilane, 0.25 g of a 0.5 mass% toluene solution of chloroplatinic acid (H2PtCl6·6H2O), and 50 mL of toluene were added, and 51.3 g (0.420 mol) of trimethoxysilane was added dropwise. After stirring at 85°C for 6 hours, the unreacted diethynyldimethylsilane was recovered by distillation, yielding 91.9 g of ethynyl(trimethoxysilyl-vinylene)dimethylsilane (reaction rate of trimethoxysilane 95%) represented by the following structural formula (4).

[0058] [ka]

[0059] [Synthesis Example 2] In a 500 mL four-necked separable flask equipped with a mechanical stirrer, thermometer, and dropping funnel, 212.1 g (1.959 mol) of diethynyldimethylsilane, 0.58 g of a 0.5 mass% toluene solution of chloroplatinic acid (H2PtCl6·6H2O), and 50 mL of toluene were added, and 53.6 g (0.506 mol) of dimethoxymethylsilane was added dropwise. After stirring at 85°C for 6 hours, the unreacted starting material, diethynyldimethylsilane, was recovered by distillation, yielding 102.9 g of ethinyl(dimethoxymethylsilyl-vinylene)dimethylsilane (reaction rate of dimethoxysilane 95%), represented by the following structural formula (7).

[0060] [ka]

[0061] [Synthesis Example 3] In a 500 mL four-necked separable flask equipped with a mechanical stirrer, thermometer, and dropping funnel, add 90.9 g (0.840 mol) of diethynyldimethylsilane, 0.25 g of a 0.5 mass% toluene solution of chloroplatinic acid (H2PtCl6·6H2O), and 50 mL of toluene, and then add 35.6 g (0. 217 A mole was added dropwise. After stirring at 85°C for 6 hours, the unreacted starting material, diethynyldimethylsilane, was recovered by distillation, yielding 56.2 g of ethynyl(triethoxysilyl-vinylene)dimethylsilane represented by the following structural formula (9) (reaction rate of triethoxysilane: 95%).

[0062] [ka]

[0063] [Example 1-1] In a 500 mL four-neck separable flask equipped with a mechanical stirrer, thermometer, and dropping funnel, 41.6 g (0.181 mol) of ethynyl(trimethoxysilyl-vinylene)dimethylsilane represented by formula (4) obtained in Synthesis Example 1, 0.5 g of a 0.5 mass% toluene solution of chloroplatinic acid (H2PtCl6·6H2O), and 200 mL of toluene were added. 375 g (Si-H, 0.181 mol) of organopolysiloxane represented by formula (5) was added dropwise, and after stirring at 85°C for 6 hours, the toluene was removed by distillation to obtain 396 g (95% yield) of the single-ended modified organopolysiloxane (A-1) represented by formula (6). This reaction is shown in the following reaction formula [4].

[0064] [ka]

[0065] [Examples 1-2] In a 500 mL four-neck separable flask equipped with a mechanical stirrer, thermometer, and dropping funnel, 25.8 g (0.121 mol) of ethynyl(dimethoxymethylsilyl-vinylene)dimethylsilane represented by formula (7) obtained in Synthesis Example 2, 0.5 g of a 0.5 mass% toluene solution of chloroplatinic acid (H2PtCl6·6H2O), and 150 mL of toluene were added. 250 g (Si-H, 0.121 mol) of organopolysiloxane represented by formula (5) was added dropwise, and after stirring at 85°C for 6 hours, the toluene was removed by distillation to obtain 262 g (95% yield) of the single-ended modified organopolysiloxane (A-2) represented by formula (8). This reaction is shown in the following reaction formula [5].

[0066] [ka]

[0067] [Examples 1-3] In a 500 mL four-neck separable flask equipped with a mechanical stirrer, thermometer, and dropping funnel, 28.3 g (0.104 mol) of ethynyl(triethoxysilyl-vinylene)dimethylsilane represented by formula (9) obtained in Synthesis Example 3, 0.5 g of a 0.5 mass% toluene solution of chloroplatinic acid (H2PtCl6·6H2O), and 150 mL of toluene were added. 224 g (Si-H, 0.104 mol) of organopolysiloxane represented by formula (5) was added dropwise, and after stirring at 85°C for 6 hours, the toluene was removed by distillation to obtain 239 g (95% yield) of the single-ended modified organopolysiloxane (A-3) represented by formula (10). This reaction is shown in the following reaction formula [6].

[0068] [ka]

[0069] [Examples 1-4] In a 500 mL four-neck separable flask equipped with a mechanical stirrer, thermometer, and dropping funnel, 11.3 g (0.051 mol) of ethynyl(dimethoxymethylsilyl-vinylene)dimethylsilane represented by formula (7) obtained in Synthesis Example 2, 0.5 g of a 0.5 mass% toluene solution of chloroplatinic acid (H2PtCl6·6H2O), and 150 mL of toluene were added. 650 g (Si-H, 0.051 mol) of organopolysiloxane represented by formula (11) was added dropwise, and after stirring at 85°C for 6 hours, the toluene was removed by distillation to obtain 628 g (95% yield) of the single-ended modified organopolysiloxane (A-4) represented by formula (12). This reaction is shown in formula [7] below.

[0070] [ka]

[0071] [Examples 1-5] In a 500 mL four-neck separable flask equipped with a mechanical stirrer, thermometer, and dropping funnel, 5.57 g (0.025 mol) of ethynyl(dimethoxymethylsilyl-vinylene)dimethylsilane represented by formula (7) obtained in Synthesis Example 2, 0.5 g of a 0.5 mass% toluene solution of chloroplatinic acid (H2PtCl6·6H2O), and 150 mL of toluene were added. 325 g (Si-H, 0.025 mol) of organopolysiloxane represented by formula (13) was added dropwise, and after stirring at 85°C for 6 hours, the toluene was removed by distillation to obtain 310 g (94% yield) of the single-ended modified organopolysiloxane (A-5) represented by formula (14). This reaction is shown in the following reaction formula [8].

[0072] [ka]

[0073] [Examples 2-1 to 2-4, Comparative Examples 2-1, 2-2] Using a mixer, the following components were mixed in the proportions (parts by mass) shown in Table 1 to obtain a silicone composition.

[0074] (A) component (A-1): The terminally modified organopolysiloxane represented by formula (6) obtained in Example 1-1 (A-2): The terminally modified organopolysiloxane represented by formula (8) obtained in Example 1-2

[0075] (B) Component (B-1): Irregularly shaped zinc oxide powder with an average particle size of 0.3 μm.

[0076] (G) Component (G-1): Organopolysiloxane represented by the following formula (15) [ka]

[0077] (H) Component (H-1): Dimethylpolysiloxane with trimethylsiloxy groups at both ends of the molecular chain, whose viscosity at 25°C measured by a rotational viscometer is 1,000 mPa·s.

[0078] The results of the following measurements performed on the obtained silicone composition are shown in Table 1.

[0079] [viscosity] The absolute viscosity of the silicone composition was measured at 25°C using a Malcolm viscometer (Type PC-1TL) immediately after mixing (initial), after 5 days at 25°C, and after 14 days at 25°C (rotor A at 10 rpm, shear rate 6 [1 / s]). The ratio of the viscosity after 14 days at 25°C to the initial viscosity was also calculated. [Thermal conductivity] Each composition was wrapped in plastic wrap, and its thermal conductivity was measured using a TPS-2500S manufactured by Kyoto Electronics Manufacturing Co., Ltd.

[0080] [Table 1]

[0081] As shown in the evaluation results in Table 1, Examples 2-1 to 2-4 showed less viscosity change between the initial stage and after 14 days compared to Comparative Examples 2-1 and 2-2, demonstrating that the end-modified organopolysiloxane of the present invention is effective as a wetter that reduces viscosity changes in silicone compositions.

[0082] [Examples 3-1 to 3-4, Comparative Examples 3-1 to 3-4] A silicone composition was prepared by blending the following components (A) to (G) in the proportions (parts by mass) shown in Table 2, using the method described below. Components (A), (B), (C), and (G) were added to a 5-liter planetary mixer (manufactured by Inoue Seisakusho Co., Ltd.), stirring was started at 25°C, and the temperature was raised to 150°C while degassing, and the mixture was mixed at 150°C for 1 hour. After that, it was cooled to below 40°C, and components (F), (E), and (D) were added as needed, and the mixture was heated to 25°C until homogeneous to prepare the silicone composition. The kinematic viscosity is the value at 25°C measured with an Ostwald viscometer, and the SiH / SiVi ratio is the value in component (A).vinylene group and vinyl group in component (C) This is the ratio of the total number of SiH groups in component (D) to the total number of (D) groups.

[0083] (A) component (A-5): End-modified organopolysiloxane represented by formula (14) obtained in Examples 1-5 (kinematic viscosity at 25°C: 395 mm) 2 / s)

[0084] (B) Component (B-1): Irregularly shaped zinc oxide powder with an average particle size of 0.3 μm. (B-2): Mixture of aluminum powder with an average particle size of 2 μm and aluminum powder with an average particle size of 10 μm = 1:1 (mass ratio)

[0085] (C) Component (C-1): Both ends are sealed with dimethylvinylsilyl groups, and the kinematic viscosity at 25°C is 600 mmHg. 2 / s Dimethylpolysiloxane (C-2): Both ends are sealed with dimethylvinylsilyl groups, and the kinematic viscosity at 25°C is 30,000 mm². 2 / s Dimethylpolysiloxane

[0086] (D) Component (D-1): Methylhydrogendimethylpolysiloxane represented by the following formula (16) (kinematic viscosity at 25°C: 30 mm²) 2 (In the formula, the order of siloxane units can be block or random.) [ka] (D-2): Methylhydrogendimethylpolysiloxane represented by the following formula (17) (kinematic viscosity at 25°C: 40 mm) 2 (In the formula, the order of siloxane units can be block or random.) [ka]

[0087] (E) Component (E-1): A solution of platinum-divinyltetramethyldisiloxane complex dissolved in the same dimethylpolysiloxane as in (C-1) above (platinum atom content: 1% by mass)

[0088] (F) component (F-1): 1-Ethynyl-1-cyclohexanol

[0089] (G) Component (G-1): Organopolysiloxane represented by formula (15) above

[0090] The absolute viscosity and thermal conductivity of the obtained silicone composition were measured according to the method described above, and the hardness was measured according to the method described below. The results are shown in Table 2.

[0091] [hardness] Two 6mm thick cured specimens, prepared by curing a silicone composition by heating it at 150°C for 1 hour, were stacked together. The hardness of these specimens was then measured using an Asker C hardness tester after exposure to a 150°C environment for 0 hours (initial), 250 hours, 500 hours, and 1000 hours.

[0092] [Table 2]

[0093] From the evaluation results in Table 2, it can be seen that the silicone compositions of Examples 3-1 to 3-4, compared to the silicone compositions of Comparative Examples 3-1 to 3-4 which do not contain component (A), have high thermal conductivity due to the incorporation of a large amount of thermally conductive filler, while suppressing the increase in hardness after the 150°C heat resistance test. In other words, it has become clear that the silicone compositions of the present invention, when using a thermally conductive filler as a filler, can be made highly reliable as heat dissipation materials used particularly in electronic component packages and power modules.

Claims

1. A uniterminally degenerated organopolysiloxane represented by the following general formula (1). 【Chemistry 1】 (In the formula, R 1 R is a monovalent hydrocarbon group having 1 to 20 carbon atoms, which may have substituents, and R is independent of each other. 2 These are, independently of each other, C1 to C20 alkyl groups or C3 to C20 cycloalkyl groups that may have substituents. a is an integer from 1 to 3. n is a number from 1 to 300.

2. A method for producing a one-end modified organopolysiloxane represented by the following general formula (1), comprising the step of hydrosilylation reacting a bissilane compound represented by the following general formula (2) with an organohydrogenpolysiloxane represented by the following general formula (3). 【Chemistry 2】 (In the formula, R 1 R is a monovalent hydrocarbon group having 1 to 20 carbon atoms, which may have substituents, and R is independent of each other. 2 These are, independently of each other, C1 to C20 alkyl groups or C3 to C20 cycloalkyl groups that may have substituents. a is an integer from 1 to 3. n is a number from 1 to 300.

3. A surface treatment agent for powders comprising a single-ended modified organopolysiloxane as described in claim 1.

4. (A) A terminally modified organopolysiloxane represented by the following general formula (1), 【Transformation 3】 (In the formula, R 1 R is a monovalent hydrocarbon group having 1 to 20 carbon atoms, which may have substituents, and R is independent of each other. 2 These are, independently of each other, C1 to C20 alkyl groups or C3 to C20 cycloalkyl groups that may have substituents. a is an integer from 1 to 3. n is a number from 1 to 300. And, (B) Filler A silicone composition containing the following:

5. The silicone composition according to claim 4, wherein the average particle size of component (B) is 0.01 to 150 μm.

6. moreover, (C) A molecule having an aliphatic unsaturated hydrocarbon group bonded to at least two silicon atoms, a linear structure in which the main chain consists of repeating diorganosiloxane units and both ends of the main chain are sealed with triorganosiloxy groups, with a kinematic viscosity at 25°C of 60 to 100,000 mm². 2 / s organopolysiloxane, (D) Organohydrogenpolysiloxane having two or more hydrogen atoms bonded to silicon atoms in one molecule: an amount such that the number of hydrogen atoms bonded to silicon atoms relative to the total number of aliphatic unsaturated hydrocarbon groups in component (A) and component (C) is 0.5 to 5. Furthermore, (E) Platinum group metal catalyst A silicone composition according to claim 4 or 5, comprising:

7. Furthermore, the silicone composition according to claim 6, comprising (F) one or more addition reaction control agents selected from the group consisting of acetylene compounds, nitrogen compounds, organophosphorus compounds, oxime compounds and organochloro compounds.

8. Furthermore, the silicone composition according to claim 4, further comprising (G) a hydrolyzable organopolysiloxane represented by the following general formula (W) in an amount of 0.1 to 20% by mass relative to the entire composition. 【Chemistry 4】 (wherein, R 3 is, independently of one another, a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms which may have a substituent, and R 4 is, independently of one another, an alkyl group having 1 to 20 carbon atoms which may have a substituent or a cycloalkyl group having 3 to 20 carbon atoms which may have a substituent. b is an integer of 1 to 3. m is a number of 1 to 200.)

9. The silicone composition according to claim 4 or 5, wherein the filler of component (B) is a thermally conductive filler.

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