Bicyclic acetylene alcohol compound, addition-curable silicone composition, and thermally conductive addition-curable silicone composition

Abstract

The present invention is a bicyclic acetylene alcohol compound characterized in that: a hydroxyl-substituted carbon atom in the compound is a tertiary carbon atom that bonds with an acetylene group and the α-carbon in the compound is a bridged carbon atom; a hydrogen atom is not present on the α-carbon atom; or both of these conditions are satisfied. The present invention thus makes it possible to provide a bicyclic acetylene alcohol compound in which an isomerization reaction to α, β-unsaturated ketone is unlikely to occur, an addition-curable silicone composition containing the compound, and a thermally conductive addition-curable silicone composition.

Description

Bicyclic acetylene alcohol compound, addition-curable silicone composition, and thermally conductive addition-curable silicone composition

[0001] The present invention relates to a bicyclic acetylenic alcohol compound, an addition-curable silicone composition, and a thermally conductive addition-curable silicone composition.

[0002] Addition-curable silicone compositions cure to form silicone gels, silicone rubbers, hard coat films, and the like that have excellent electrical properties, cold resistance, heat resistance, and chemical stability, and are therefore widely used as sealants, fillers, or coating agents for electrical and electronic components and semiconductor elements, and insulating coating protectants for optical semiconductors. Furthermore, blending various inorganic fillers can increase the strength of the composition and impart heat resistance. Furthermore, they are also used as heat-dissipating and conductive materials for electronic components such as semiconductor elements and LED substrates.

[0003] In order to initiate the curing reaction (hydrosilylation reaction) of an addition-curable silicone composition at the desired timing, it is essential to control the pot life and shelf life, and several means for this purpose have been proposed. For example, a microcapsule structure in which a hydrosilylation reaction catalyst is embedded in a polymer compound has been proposed (see, for example, Patent Documents 1 and 2). However, the hydrosilylation reaction catalyst embedded inside the microcapsule structure diffuses slowly into the composition, which poses the problem of making it difficult to initiate the addition curing reaction.

[0004] Another method involves blending an addition curing reaction inhibitor selected from acetylene compounds, nitrogen compounds, organic phosphorus compounds, oxime compounds, organic chloro compounds, etc. (Patent Document 3). By blending an appropriate amount of these addition curing reaction inhibitors, it is possible to control the pot life and shelf life, and initiate the curing reaction of the addition-curable silicone composition at the desired timing. Acetylene alcohols are often used because they have a low odor and pose a small environmental burden.

[0005] As mentioned above, acetylene alcohols are useful as addition curing reaction inhibitors, but they are known to undergo isomerization to α,β-unsaturated ketones in the presence of acid (Meyer-Schuster rearrangement, Rupe rearrangement) (Non-Patent Document 1). The addition curing reaction inhibitory ability of the isomerized α,β-unsaturated ketone is greatly reduced, which poses the problem of significantly shortening the pot life and shelf life of addition-curable silicone compositions.

[0006] JP 11-236508 A JP 2014-024986 JP 04-046962

[0007] J. Org. Chem. 1977, 42, 3403

[0008] Therefore, the present invention has been made in consideration of the above circumstances, and has an object to provide a bicyclic acetylene alcohol compound that is less likely to undergo an isomerization reaction to form an α,β-unsaturated ketone, as well as an addition-curable silicone composition and a thermally conductive addition-curable silicone composition that contain the compound.

[0009] In order to solve the above problems, the present invention provides a bicyclic acetylenic alcohol compound, in which the carbon atom substituted with a hydroxyl group in the compound is a tertiary carbon atom bonded to an acetylene group, and the α-carbon in the compound is a bridgehead carbon, or there is no hydrogen atom on the α-carbon, or both. Here, the α-carbon refers to the two carbon atoms other than the acetylene group that are adjacent to the carbon atom substituted with a hydroxyl group.

[0010] Such bicyclic acetylene alcohol compounds are less likely to undergo an isomerization reaction to form α,β-unsaturated ketones, and when incorporated as an addition curing reaction inhibitor in an addition curing silicone composition or a thermally conductive addition curing silicone composition, the pot life and shelf life are less likely to be shortened.

[0011] In the present invention, the minimum number of carbon atoms constituting the ring is preferably 7 or less.

[0012] Such bicyclic acetylene alcohol compounds are less likely to undergo an isomerization reaction to form an α,β-unsaturated ketone, and when incorporated as an addition curing reaction inhibitor in an addition curing silicone composition or a thermally conductive addition curing silicone composition, they are less likely to shorten the pot life or shelf life.

[0013] The present invention also provides an addition-curable silicone composition that contains an effective amount of the bicyclic acetylenic alcohol compound described above as an addition-curing reaction inhibitor.

[0014] Such an addition-curable silicone composition is an addition-curable silicone composition whose pot life and shelf life are unlikely to be shortened.

[0015] The present invention also provides a thermally conductive addition-curable silicone composition, comprising: (A) a silicone compound having at least one aliphatic unsaturated hydrocarbon group per molecule and having a kinematic viscosity at 25°C of 60 to 100,000 mm ２ (B) at least one thermally conductive filler selected from the group consisting of metals, metal oxides, metal hydroxides, metal nitrides, metal carbides, and carbon allotropes: in an amount of 10 to 98 mass % based on the total composition; (C) an organohydrogenpolysiloxane having two or more silicon-bonded hydrogen atoms per molecule: in an amount sufficient to cause the composition to form a cured product; (D) a platinum group metal catalyst: in an effective amount; and (E) the bicyclic acetylene alcohol compound described above: in an effective amount.

[0016] Such a thermally conductive addition-curable silicone composition has excellent heat dissipation properties and is less likely to shorten its pot life or shelf life.

[0017] In this case, the component (B) is preferably silver powder.

[0018] Such a thermally conductive addition-curable silicone composition has even better heat dissipation properties.

[0019] In addition, in the present invention, it is preferable that the thermally conductive addition-curable silicone composition further contains: (F) a phenol compound represented by the following general formula (1A): (In general formula (1A), R １ represents a hydrogen atom, a halogen atom, a cyano group, or a hydroxyl group. Az represents a linear, branched, or cyclic hydrocarbon group having 1 to 20 carbon atoms and a valence of (ka+2), or a fluorinated hydrocarbon group, and —CH ２ - is -O-, -C(=O)-, or -Si(R ２ R ３ )- may be substituted. ２ , R ３ is a linear, branched, or cyclic alkyl group having 1 to 6 carbon atoms, or a phenyl group, and —CH ２ - is -O-, -C(=O)-, or -Si(CH ３ ) ２ - may be substituted. Each Xf independently represents a hydrogen atom, a halogen atom, a linear, branched, or cyclic monovalent hydrocarbon group having 1 to 10 carbon atoms which may be substituted with a fluorine atom, an alkoxy group having 1 to 10 carbon atoms which may be substituted with a fluorine atom, or an electron-withdrawing group. Z represents a single bond or an oxygen atom. Each ring ZZ independently represents an aromatic monocyclic or polycyclic ring having 3 to 20 carbon atoms. A carbon atom of the ring ZZ may be substituted with a nitrogen atom, an oxygen atom, or a sulfur atom. ka represents an integer of 0 to 2. kb and kd represent 1 or 2. kc and ke represent integers of 0 to 2.

[0020] Such a thermally conductive addition-curable silicone composition will more reliably exhibit excellent heat dissipation properties.

[0021] In this case, the component (F) is preferably a phenol compound represented by the following general formula (1B). In the general formula (1B), Az′ represents a linear, branched, or cyclic hydrocarbon group having 1 to 19 carbon atoms and a valence of (ka′+2), or a fluorinated hydrocarbon group, and —CH ２ - is -O-, -C(=O)-, or -Si(R ２ R３ )-. ka' represents 0 or 1. kb', kc', kd', and ke' represent 1 or 2. R １ , R ２ , R ３ is the same as above.)

[0022] Such a thermally conductive addition-curable silicone composition will more reliably exhibit excellent heat dissipation properties.

[0023] As described above, the bicyclic acetylenic alcohol compounds of the present invention are tertiary acetylenic alcohol compounds in which the α-carbon is a bridgehead carbon, or there is no hydrogen atom on the α-carbon, or both, and therefore are less likely to undergo isomerization to α,β-unsaturated ketones. As a result, when incorporated as an addition curing reaction inhibitor in addition-curable silicone compositions or thermally conductive addition-curable silicone compositions, the pot life and shelf life are less likely to be shortened.

[0024] As described above, there has been a need for the development of bicyclic acetylenic alcohol compounds that are less susceptible to isomerization to α,β-unsaturated ketones.

[0025] As a result of extensive research into the above-mentioned problems, the present inventors have found that the above-mentioned problems can be solved by a tertiary acetylene alcohol compound in which the α-carbon is a bridgehead carbon, or there is no hydrogen atom on the α-carbon, or both. Based on this finding, the present invention has been completed.

[0026] That is, the present invention is a bicyclic acetylene alcohol compound, in which the carbon atom substituted with a hydroxyl group in the compound is a tertiary carbon atom bonded to an acetylene group, and the α-carbon in the compound is a bridgehead carbon, or there is no hydrogen atom on the α-carbon, or both of these are satisfied.

[0027] The present invention will be described in detail below, but is not limited thereto. In the following description, some structures represented by chemical formulas may have asymmetric carbon atoms, and enantiomers or diastereoisomers may exist. In such cases, a single formula will be used to represent all of the isomers. These isomers may be used alone or as a mixture.

[0028] [Bicyclic acetylene alcohol compound] The present invention relates to a bicyclic acetylene alcohol compound, in which the carbon atom substituted with a hydroxyl group in the compound is a tertiary carbon atom bonded to an acetylene group, and the α-carbon in the compound is a bridgehead carbon, or there is no hydrogen atom on the α-carbon, or both. Such a compound can be suitably used as an addition curing reaction inhibitor for addition curing silicone compositions or thermally conductive addition curing silicone compositions.

[0029] In the present invention, the α carbon refers to two carbon atoms other than the acetylene group that are adjacent to the carbon atom substituted with a hydroxyl group.

[0030] This structure makes it difficult for the isomerization reaction to form an α,β-unsaturated ketone to occur, and therefore the ability to control the addition curing reaction is less likely to decrease, and the pot life and shelf life of the addition-curable silicone composition and thermally conductive addition-curable silicone composition are less likely to be shortened.

[0031] Specific examples of the bicyclic acetylene alcohol compound include the following:

[0032]

[0033]

[0034] The method for synthesizing the bicyclic acetylene alcohol compound of the present invention is not particularly limited, and an optimum method can be selected depending on the structure, but for example, the compound can be obtained by reacting a corresponding bicyclic ketone compound with an ethynyl magnesium halide and treating the resulting mixture with an acid, and if necessary, the compound can be purified by a conventional method such as distillation, recrystallization, or chromatography.

[0035] Furthermore, the bicyclic acetylene alcohol compound of the present invention preferably has a minimum ring-constituting carbon atom number of 7 or less. The lower limit of the minimum ring-constituting carbon atom number can be, for example, 3.

[0036] Cyclic alkenes with seven or fewer members and trans-configured double bonds cannot exist stably, and therefore bicyclic acetylene alcohol compounds with a ring containing seven or fewer carbon atoms are less likely to undergo isomerization to α,β-unsaturated ketones. As a result, the ability to control the addition curing reaction is less likely to decrease, and the pot life and shelf life of the addition-curable silicone composition and thermally conductive addition-curable silicone composition are less likely to be shortened.

[0037] [Addition-Curable Silicone Composition] The addition-curable silicone composition of the present invention contains an effective amount of the bicyclic acetylene alcohol compound described above as an addition-cure reaction inhibitor.

[0038] There are no particular limitations on the molecular structure or amount of the organopolysiloxane or organohydrogenpolysiloxane having an aliphatic unsaturated hydrocarbon group contained in the addition-curable silicone composition, the presence or absence, type and amount of filler, type and amount of curing catalyst, or whether or not other components are included, but the bicyclic acetylene alcohol compound of the present invention is particularly effective in terms of its ability to extend the pot life and shelf life of compositions containing acidic components.

[0039] [Thermal-conductive addition-curable silicone composition] The thermal-conductive addition-curable silicone composition of the present invention contains the bicyclic acetylene alcohol compound described above as component (E), components (A) to (D) described below, and, if necessary, component (F) and / or other components. Each component is described in detail below.

[0040] Component (A) Component (A) has at least one, preferably 1 to 100, more preferably 2 to 50 aliphatic unsaturated hydrocarbon groups per molecule, and has a kinematic viscosity at 25°C of 60 to 100,000 mm ２ and organopolysiloxanes in which

[0041] The aliphatic unsaturated hydrocarbon group 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, and even more preferably an alkenyl group. Examples of alkenyl groups include vinyl, allyl, propenyl, isopropenyl, butenyl, hexenyl, cyclohexenyl, and octenyl groups. Vinyl groups are particularly preferred. The aliphatic unsaturated hydrocarbon group may be bonded to a silicon atom at the molecular chain terminal, a silicon atom in the molecular chain, or both.

[0042] The organic group other than an aliphatic unsaturated hydrocarbon group bonded to the silicon atom of the organopolysiloxane is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 18 carbon atoms, preferably 1 to 10 carbon atoms, and more preferably 1 to 8 carbon atoms. Examples include alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, cyclohexyl, octyl, nonyl, and decyl; aryl groups such as phenyl, tolyl, xylyl, and naphthyl; aralkyl groups such as benzyl, phenylethyl, and phenylpropyl; and groups in which some or all of the hydrogen atoms of these groups have been substituted with halogen atoms such as fluorine, bromine, or chlorine, or with cyano groups, such as chloromethyl, chloropropyl, bromoethyl, trifluoropropyl, and cyanoethyl. Methyl and trifluoropropyl groups are particularly preferred.

[0043] The organopolysiloxane has a kinematic viscosity at 25°C of 60 to 100,000 mm ２ / s, preferably 100 to 30,000 mm ２ / s. The kinematic viscosity is 60 mm ２ / s or more, the physical properties of the thermally conductive addition-curable silicone composition will be excellent, and ２ If the viscosity is less than 1 / s, the thermally conductive addition-curable silicone composition will have excellent extensibility.

[0044] In the present invention, the kinematic viscosity is a value measured at 25° C. using an Ubbelohde-type Ostwald viscometer (the same applies hereinafter).

[0045] The molecular structure of the organopolysiloxane is not particularly limited as long as it has the above properties, and examples thereof include a linear structure, a branched structure, a partially branched structure, and a linear structure having a cyclic structure. A linear structure in which the main chain is composed of repeating diorganosiloxane units and both molecular chain terminals are capped with triorganosiloxy groups is particularly preferred. The linear organopolysiloxane may also have a partially branched or cyclic structure.

[0046] The blending amount of component (A) is preferably 1.5 to 89% by mass, more preferably 1.7 to 50% by mass, and even more preferably 2 to 20% by mass, of the total composition. If the blending amount of component (A) is 89% by mass or less, the composition will have excellent thermal conductivity, and if it is 1.5% by mass or more, the viscosity of the composition will not increase more than necessary, and the composition will have excellent workability.

[0047] The organopolysiloxanes may be used alone or in combination of two or more.

[0048] Component (B) Component (B) is one or more thermally conductive fillers selected from the group consisting of metals, metal oxides, metal hydroxides, metal nitrides, metal carbides, and carbon allotropes. Examples include aluminum, silver, copper, metallic silicon, zinc oxide, magnesium oxide, aluminum oxide (alumina), silicon dioxide, cerium oxide, iron oxide, aluminum hydroxide, cerium hydroxide, aluminum nitride, boron nitride, silicon carbide, diamond, graphite, carbon nanotubes, and graphene. However, silver, particularly silver powder, is preferred due to its excellent thermal conductivity. These fillers can be used alone or in appropriate combinations of two or more, and the ratio is not particularly limited and can be freely selected.

[0049] If the average particle size of component (B) is 0.01 μm or more, the viscosity of the resulting composition will not be too high and the composition will have excellent extensibility, and if it is 300 μm or less, the resulting composition will be uniform, so it is preferably in the range of 0.01 to 300 μm, more preferably 0.1 to 100 μm, and even more preferably 1 to 50 μm. The average particle size can be determined, for example, as the volume-based average value (or median diameter) in particle size distribution measurement by laser light diffraction method.

[0050] The component (B) can be used alone or in combination of two or more types, and the ratio is not particularly limited and can be any ratio.

[0051] The shape of component (B) is not particularly limited and may be flake-like, spherical, granular, irregular, dendritic, needle-like, or the like.

[0052] The blending amount of component (B) is preferably 10 to 98% by mass, more preferably 40 to 96% by mass, and even more preferably 70 to 95% by mass, based on the total mass of the composition. If the blending amount of component (B) is 98% by mass or less, the composition will have excellent extensibility, and if it is 10% by mass or more, the composition will have excellent thermal conductivity.

[0053] Component (C) is an organohydrogenpolysiloxane having two or more silicon-bonded hydrogen atoms per molecule, i.e., an organohydrogenpolysiloxane having two or more silicon-bonded hydrogen atoms (SiH groups) per molecule, particularly preferably 2 to 100, and even more preferably 2 to 50. The organohydrogenpolysiloxane may be any organohydrogenpolysiloxane as long as the SiH groups in the molecule can undergo an addition reaction with the aliphatic unsaturated hydrocarbon groups in component (A) described above in the presence of a platinum group metal catalyst, component (D) described below, to form a crosslinked structure.

[0054] The molecular structure of the organohydrogenpolysiloxane is not particularly limited as long as it has the above properties, and examples thereof include a linear structure, a branched structure, a cyclic structure, a partially branched structure, and a linear structure having a cyclic structure, etc. A linear structure or a cyclic structure is preferred.

[0055] The organohydrogenpolysiloxane preferably has a kinematic viscosity at 25°C of 1 to 1,000 mm ２ / s, more preferably 10 to 300 mm ２ / s. The kinematic viscosity is 1 mm ２ / s or more, the physical properties of the thermally conductive addition-curable silicone composition will be excellent, and ２ If the viscosity is 1 / s or less, the thermally conductive addition-curable silicone composition will have good extensibility.

[0056] The organic group bonded to the silicon atom of the organohydrogenpolysiloxane may be an unsubstituted or substituted monovalent hydrocarbon group other than an aliphatic unsaturated hydrocarbon group. Particularly preferred 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; aryl groups such as phenyl; aralkyl groups such as 2-phenylethyl and 2-phenylpropyl; and groups in which some or all of the hydrogen atoms have been substituted with halogen atoms such as fluorine, bromine, and chlorine; cyano groups; and epoxy ring-containing organic groups (glycidyl or glycidyloxy-substituted alkyl groups), such as chloromethyl, chloropropyl, bromoethyl, trifluoropropyl, cyanoethyl, 2-glycidoxyethyl, 3-glycidoxypropyl, and 4-glycidoxybutyl. Of these, methyl and trifluoropropyl groups are preferred.

[0057] The organohydrogenpolysiloxanes may be used alone or in combination of two or more.

[0058] The amount of organohydrogenpolysiloxane in component (C) is an effective amount sufficient to enable the composition to form a cured product, preferably an amount such that the ratio of the number of SiH groups in component (C) to the total number of aliphatic unsaturated hydrocarbon groups in component (A) is 0.5 to 10, more preferably 0.7 to 7.5, and even more preferably 1.0 to 5.0. When the amount of component (C) is at least the lower limit, the addition reaction proceeds sufficiently, resulting in sufficient crosslinking. When the amount is at most the upper limit, the crosslinked structure is uniform, resulting in good shelf life for the composition.

[0059] Component (D) Component (D) is a platinum group metal catalyst that functions to promote the addition curing reaction of the above-mentioned components. Any conventionally known platinum group metal catalyst used in addition curing reactions can be used. Examples include platinum-based, palladium-based, and rhodium-based catalysts, with platinum or platinum compounds being preferred, as they are relatively readily available. Examples include platinum itself, platinum black, chloroplatinic acid, platinum-olefin complexes, platinum-alcohol complexes, and platinum coordination compounds. Platinum group metal catalysts may be used alone or in combination of two or more.

[0060] The amount of component (D) blended should be an effective catalytic amount, i.e., an effective amount necessary to promote the addition curing reaction and cure the thermally conductive addition-curable silicone composition of the present invention. It is preferably 0.1 to 500 ppm, more preferably 0.5 to 300 ppm, and even more preferably 1 to 200 ppm, by mass, calculated as platinum group metal atoms, relative to the total composition. When the blending amount of component (D) is at least the lower limit, the catalytic effect is obtained, while when it is at most the upper limit, the catalytic effect is sufficient and economical.

[0061] Component (E) The thermally conductive addition-curable silicone composition of the present invention contains the above-described bicyclic acetylene alcohol compound as component (E) as an addition-curing reaction inhibitor.

[0062] The amount of component (E) may be an effective amount, preferably 0.05 to 10 parts by mass, more preferably 0.07 to 5 parts by mass, and even more preferably 0.1 to 2 parts by mass, per 100 parts by mass of component (A). When the amount of component (E) is 0.05 part by mass or more, the desired sufficient shelf life and pot life are obtained, while when it is 10 parts by mass or less, the silicone composition has sufficient curability.

[0063] The bicyclic acetylene alcohol compounds of component (E) may be used either individually or in combination of two or more.

[0064] Furthermore, component (E) may be diluted with an organo(poly)siloxane, toluene, or the like to improve dispersibility in the thermally conductive addition-curable silicone composition.

[0065] In addition to the components described above, the following optional components may also be added to the thermally conductive addition-curable silicone composition of the present invention, as needed.

[0066] Component (F) Component (F) is a phenolic compound that is blended as an additive in the thermally conductive addition-curable silicone composition. The phenolic compound is preferably a phenolic compound represented by the following general formula (1A). In the following explanation, some structures represented by chemical formulas may have asymmetric carbons, leading to the existence of enantiomers or diastereoisomers. In such cases, a single formula will be used to represent all of the isomers. These isomers may be used alone or as a mixture. (In general formula (1A), R １ represents a hydrogen atom, a halogen atom, a cyano group, or a hydroxyl group. Az represents a linear, branched, or cyclic hydrocarbon group having 1 to 20 carbon atoms and a valence of (ka+2), or a fluorinated hydrocarbon group, and —CH ２ - is -O-, -C(=O)-, or -Si(R ２ R ３ )- may be substituted. ２ , R ３ is a linear, branched, or cyclic alkyl group having 1 to 6 carbon atoms, or a phenyl group, and —CH ２ - is -O-, -C(=O)-, or -Si(CH ３ ) ２ - may be substituted. Each Xf independently represents a hydrogen atom, a halogen atom, a linear, branched, or cyclic monovalent hydrocarbon group having 1 to 10 carbon atoms which may be substituted with a fluorine atom, an alkoxy group having 1 to 10 carbon atoms which may be substituted with a fluorine atom, or an electron-withdrawing group. Z represents a single bond or an oxygen atom. Each ring ZZ independently represents an aromatic monocyclic or polycyclic ring having 3 to 20 carbon atoms. A carbon atom of the ring ZZ may be substituted with a nitrogen atom, an oxygen atom, or a sulfur atom. ka represents an integer of 0 to 2. kb and kd represent 1 or 2. kc and ke represent integers of 0 to 2.

[0067] Specific examples of the linear, branched or cyclic (ka+2)-valent hydrocarbon group having 1 to 20 carbon atoms for Az include the following: (In the formula, the dashed lines represent bonds.)

[0068] (In the formula, the dashed lines represent bonds.)

[0069] (In the formula, the dashed lines represent bonds.)

[0070] Specific examples of the linear, branched, or cyclic (ka+2)-valent fluorinated hydrocarbon group having 1 to 20 carbon atoms represented by Az include the above hydrocarbon groups in which some or all of the hydrogen atoms have been substituted with fluorine atoms. ２ - is -O-, -C(=O)-, or -Si(R ２ R ３ The number of carbon atoms in Az is preferably 2 to 18, more preferably 3 to 16, and even more preferably 4 to 14. In addition, the —CH ２ A part of - is -Si(R ２ R ３ ) - or -Si(R ２ R ３ )-O- is preferably substituted.

[0071] R ２ , R ３ Specific examples of the linear, branched, or cyclic alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an n-hexyl group, a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, and a cyclohexyl group.

[0072] Specific examples of the halogen atom of Xf include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0073] Specific examples of Xf as a linear, branched, or cyclic monovalent hydrocarbon group having 1 to 10 carbon atoms which may be substituted with a fluorine atom include alkyl groups such as a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, a cyclopropyl group, and a cyclobutyl group; a trifluoromethyl group; and a 2,2,2-trifluoroethyl group.

[0074] Specific examples of the alkoxy group having 1 to 10 carbon atoms for Xf which may be substituted with a fluorine atom include a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, an n-butoxy group, a sec-butoxy group, a tert-butoxy group, a cyclopropoxy group, a trifluoromethoxy group, and a 2,2,2-trifluoroethoxy group.

[0075] Specific examples of the electron-withdrawing group of Xf include a carbonyl group, an alkoxycarbonyl group, a cyano group, a nitro group, a sulfo group, a formyl group, a sulfonate ester group, an amide group, and —O—C(═O)-G- (wherein G is a sulfur atom or NH).

[0076] Specific examples of the aromatic monocyclic or polycyclic ring having 3 to 20 carbon atoms for ring ZZ include the following: Ring ZZ may further have a substituent as shown below.

[0077] It is particularly preferred that the component (F) is a phenol compound represented by the following general formula (1B). In the general formula (1B), Az′ represents a linear, branched, or cyclic hydrocarbon group having 1 to 19 carbon atoms and a valence of (ka′+2), or a fluorinated hydrocarbon group, and —CH ２ - is -O-, -C(=O)-, or -Si(R ２ R ３ )-. ka' represents 0 or 1. kb', kc', kd', and ke' represent 1 or 2. R １ , R ２ , R ３ is the same as above.)

[0078] Specific examples of the phenol compounds represented by the above general formulas (1A) and (1B) are as follows:

[0079]

[0080]

[0081]

[0082]

[0083]

[0084]

[0085] The blend amount of component (F) is preferably 0.01 to 10% by mass, more preferably 0.03 to 5% by mass, and even more preferably 0.05 to 1.0% by mass, of the total composition. When the blend amount of component (F) is 0.01% by mass or more, it has the effect of contributing to improving the heat dissipation properties of the thermally conductive addition-curable silicone composition, and when it is 10% by mass or less, the effect of improving heat dissipation is sufficient and it is economical.

[0086] Other Components The thermally conductive addition-curable silicone composition of the present invention may contain a non-reactive organo(poly)siloxane, such as methylpolysiloxane, to adjust the strength and viscosity of the composition. Furthermore, hydrolyzable organopolysiloxanes, various modified silicones, and hydrolyzable organosilanes may be blended to improve the filling properties of the thermally conductive filler or to impart adhesive properties to the composition. Furthermore, a solvent may be blended to adjust the viscosity of the composition. Furthermore, to prevent deterioration of the thermally conductive addition-curable silicone composition, a conventionally known antioxidant, such as 2,6-di-tert-butyl-4-methylphenol, may be added as needed. Furthermore, dyes, pigments, flame retardants, anti-settling agents, thixotropy improvers, and the like may be blended as needed.

[0087] Method for Producing Thermally Conductive Addition-Curable Silicone Composition The method for producing the thermally conductive addition-curable silicone composition of the present invention is not particularly limited, but comprises the step of producing a thermally conductive addition-curable silicone composition containing the above-mentioned components (A) to (E), and, if necessary, component (F) and / or other components.

[0088] The above-mentioned components (A) to (E), and optionally component (F) and other components, are mixed at 25°C for typically 3 minutes to 24 hours, preferably 5 minutes to 12 hours, and particularly preferably 10 minutes to 6 hours, using a mixer such as Trimix, Twinmix, or Planetary Mixer (all registered trademarks of mixers manufactured by Inoue Seisakusho Co., Ltd.), Ultramix (registered trademark of mixers manufactured by Mizuho Industries Co., Ltd.), or Hivismix (registered trademark of mixers manufactured by Primix Corporation). Degassing may be performed during mixing, and mixing may be performed while heating at a temperature in the range of 40 to 170°C.

[0089] In the present invention, from the perspective of enabling the thermally conductive addition-curable silicone composition to exhibit good thermal conductivity, it is preferable to first mix components (A) and (B) at 70° C., and then mix components (C), (D), and (E) at 25° C. When the optional component (F) is added, it is preferable to first mix components (A) and (B), then mix component (F), and then mix components (C), (D), and (E).

[0090] The thermally conductive addition-curable silicone composition of the present invention preferably has a viscosity measured at 25°C of 10 to 1,000 Pa·s, more preferably 20 to 700 Pa·s, and even more preferably 40 to 600 Pa·s. A viscosity of 10 Pa·s or higher facilitates shape retention and prevents the thermally conductive filler from settling, resulting in good workability. Furthermore, a viscosity of 1,000 Pa·s or lower facilitates discharge and application, resulting in good workability. The viscosity can be obtained by adjusting the blending amounts of the above-mentioned components. The viscosity can be measured at 25°C, for example, using a Malcom viscometer (Type PC-1T).

[0091] Furthermore, the cured product of the thermally conductive addition-curable silicone composition of the present invention typically has a thermal conductivity of 0.5 to 100 W / m·K. The thermal conductivity can be calculated, for example, from the following formula: (thickness of silicone composition [μm]) ÷ (thermal resistance value of silicone composition [mm ２ The thermal resistance can be measured using, for example, Nanoflash (manufactured by Nitsche, LFA447).

[0092] The curing conditions for heat curing the thermally conductive addition-curable silicone composition of the present invention are not particularly limited, but are typically 80 to 200°C, preferably 100 to 180°C, for 15 minutes to 4 hours, preferably 30 minutes to 2 hours.

[0093] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples. Structural analysis of the compounds was carried out using a BRUKER AVANCEIII HD NanoBay 400 MHz nuclear magnetic resonance spectrometer and a PerkinElmer Spectrum One Fourier transform infrared spectrometer.

[0094] The bicyclic acetylene alcohol compounds 1 to 3 of the present invention were synthesized by the following method.

[0095] [Synthesis Example 1] Synthesis of bicyclic acetylene alcohol compound 1 Under a nitrogen atmosphere, bicyclo[3.3.1]nonan-9-one (0.69 g) was dissolved in THF (5.0 ml) and cooled to 0°C. A 0.5 M ethynylmagnesium bromide THF solution (15.0 ml) was carefully added dropwise thereto at an internal temperature of 10°C or below. The mixture was then stirred at room temperature for 24 hours. Subsequently, 0.5 N aqueous hydrochloric acid (20.0 ml) was added, and the mixture was stirred at room temperature for 10 minutes. After separating the organic layer, the aqueous layer was extracted three times with ethyl acetate (40 ml). The combined organic layer was neutralized and washed with tap water. Dehydrated sodium sulfate (40 g) was added to the organic layer after neutralization and washing, and the mixture was stirred at room temperature for 3 hours. After filtering off the sodium sulfate, the mixture was concentrated to obtain bicyclic acetylene alcohol compound 1 (0.70 g, yield 85%) as a light brown solid. １H-NMR (400MHz in DMSO-d6): δ = 5.24 (1H, s), 3.25 (1H, s), 2.10-1.32 (14H, m) ppm.

[0096] [Synthesis Example 2] Synthesis of bicyclic acetylene alcohol compound 2 Under a nitrogen atmosphere, 3-methylene-2-norbornanone (2.44 g) was dissolved in THF (20 ml) and cooled to 0°C. A 0.5 M ethynylmagnesium bromide THF solution (60.0 ml) was carefully added dropwise thereto at an internal temperature of 10°C or below. The mixture was then stirred at room temperature for 24 hours. Subsequently, 0.5 N aqueous hydrochloric acid (80.0 ml) was added, and the mixture was stirred at room temperature for 10 minutes. After separating the organic layer, the aqueous layer was extracted three times with ethyl acetate (120 ml). The combined organic layer was neutralized and washed with tap water. Dehydrated sodium sulfate (140 g) was added to the organic layer after neutralization and washing, and the mixture was stirred at room temperature for 3 hours. After filtering off the sodium sulfate, the mixture was concentrated to obtain bicyclic acetylene alcohol compound 2 (2.48 g, yield 84%) as an orange-brown, transparent liquid. １ H-NMR (400MHz in DMSO-d6): δ = 5.63 (1H, s), 4.96 (1H, s), 4.85 (1H, s), 3.20 (1H, s), 2.67 (1H, s), 2.31 (1H, s), 1.87 to 1.27 (8H, m) ppm.

[0097] [Synthesis Example 3] Synthesis of bicyclic acetylene alcohol compound 3 Under a nitrogen atmosphere, (+)-fenchone (2.28 g) was dissolved in THF (15 ml) and cooled to 0°C. A 0.5 M ethynylmagnesium bromide THF solution (45.0 ml) was carefully added dropwise thereto at an internal temperature of 10°C or below. The mixture was then stirred at 50°C for 7 hours. Subsequently, 0.5 N aqueous hydrochloric acid (60.0 ml) was added, and the mixture was stirred at room temperature for 10 minutes. After separating the organic layer, the aqueous layer was extracted three times with ethyl acetate (80 ml). The combined organic layer was neutralized and washed with tap water. Dehydrated sodium sulfate (70 g) was added to the organic layer after neutralization and washing, and the mixture was stirred at room temperature for 3 hours. After filtering off the sodium sulfate, the mixture was concentrated to obtain bicyclic acetylene alcohol compound 3 (2.04 g, 76% yield) as a pale orange, transparent liquid. １H-NMR (400MHz in DMSO-d6): δ = 5.01 (1H, s), 3.26 (1H, s), 2.11 (1H, s), 1.89-0.85 (16H, m) ppm.

[0098] The following components were prepared to prepare the thermally conductive addition-curable silicone composition of the present invention: The kinematic viscosity was measured at 25°C using an Ubbelohde-Ostwald viscometer.

[0099] Component (A) A-1: ​​A copolymer having both ends capped with dimethylvinylsilyl groups and a kinematic viscosity of 600 mm at 25°C. ２ / s dimethylpolysiloxane (SiVi = 0.014 mol / 100 g)

[0100] (B) Component B-1: Average particle size 2 μm, tap density 2.4 g / mL, specific surface area 0.9 m ２ / g Flake silver powder B-2: average particle size 3 μm, tap density 7.0 g / mL, specific surface area 0.2 m ２ / g of spherical silver powder

[0101] Component (C) C-1: Methylhydrogendimethylpolysiloxane represented by the following formula (2) (kinematic viscosity at 25°C = 100 mm ２ / s, SiH = 0.0055 mol / g)

[0102] Component (D) D-1: A solution of platinum-divinyltetramethyldisiloxane complex dissolved in the same dimethylpolysiloxane as in A-1 (platinum atom content: 1% by mass)

[0103] Component (E) E-1: Bicyclic acetylene alcohol compound 1 synthesized in Synthesis Example 1 and represented by the following formula (3): E-2: A solution of the bicyclic acetylene alcohol compound 1 synthesized in Synthesis Example 1 represented by the above formula (3) dissolved in toluene (bicyclic acetylene alcohol compound 1 content: 50% by mass). E-3: A bicyclic acetylene alcohol compound 2 synthesized in Synthesis Example 2 represented by the following formula (4). e-4 (for comparison): Acetylenic alcohol compound represented by the following formula (5): e-5 (for comparison): Acetylenic alcohol compound represented by the following formula (6):

[0104] Component (F) F-1: a phenol compound represented by the following formula (7)

[0105] Examples 1-3, Comparative Examples 1-3: Preparation of Thermally Conductive Addition-Curable Silicone Compositions Thermally conductive addition-curable silicone compositions were prepared by blending the above components (A) to (F) in the amounts shown in Tables 1-2 using the method described below. In the tables, SiH / SiVi refers to the ratio of the total number of SiH groups in component (C) to the total number of alkenyl groups in component (A). Components (A) and (B) were added to 0.3 liters of Hibismix (manufactured by Primix Corporation) and mixed at 70°C for 1 hour. After cooling to 40°C or below, components (F), (E), (D), and (C) were added and mixed until uniform, preparing thermally conductive addition-curable silicone compositions. The viscosity, thermal conductivity, and 25°C pot life of each thermally conductive addition-curable silicone composition obtained by the above method were measured according to the following methods. The results are shown in Tables 1-2.

[0106] [Viscosity] The absolute viscosity of each thermally conductive addition-curable silicone composition was measured at 25° C. using a Malcom viscometer (Type PC-1T) (rotor A, 10 rpm, shear rate 6 [1 / s]).

[0107] [Thermal Conductivity] Each thermally conductive addition-curable silicone composition was sandwiched between two 12.7 mm diameter silicon plates and heat-cured at 125°C for 1 hour under a pressure of 0.14 MPa to prepare test pieces for measuring thermal resistance, and the thermal resistance value of the cured thermally conductive addition-curable silicone was measured. Furthermore, the thickness of the test piece was measured with a microgauge, and the thickness of the cured thermally conductive addition-curable silicone was calculated from the difference with the thickness of the silicon plate that had been measured in advance. The thermal conductivity of the cured thermally conductive addition-curable silicone was then derived using the following formula: (thickness of the cured thermally conductive addition-curable silicone, μm) ÷ (thermal resistance value of the cured thermally conductive addition-curable silicone, mm ２ *K / W) For the thermal resistance measurement, Nanoflash (manufactured by Nitsche, LFA447) was used.

[0108] [25°C Pot Life] The absolute viscosity of each thermally conductive addition-curable silicone composition was measured at 25°C using a Malcolm viscometer (Type PC-1T) (rotor A at 10 rpm, shear rate of 6 [1 / s]), and then the absolute viscosity after storage at 25°C for 24 hours was measured in the same manner, and the difference in viscosity before and after storage was calculated.

[0109]

[0110]

[0111] The results in Table 1 show that the thermally conductive addition-curable silicone compositions of Examples 1 to 3, which contained a bicyclic acetylene alcohol compound of the present invention as an addition-curing reaction inhibitor, showed a small difference between the initial viscosity and the viscosity after storage at 25°C for 24 hours.

[0112] On the other hand, the results in Table 2 show that the thermally conductive addition-curable silicone compositions of Comparative Examples 1 to 3, which did not contain the bicyclic acetylene alcohol compound of the present invention as an addition-curing reaction inhibitor, showed a large difference between the initial viscosity and the viscosity after storage at 25°C for 24 hours.

[0113] That is, it can be seen that the pot life at 25°C of a thermally conductive addition-curable silicone composition containing the bicyclic acetylene alcohol compound of the present invention as an addition-curing reaction inhibitor is extended.

[0114] This specification encompasses the following aspects. [1]: A bicyclic acetylene alcohol compound, wherein the carbon atom substituted with a hydroxyl group in the compound is a tertiary carbon atom bonded to an acetylene group, and wherein the α-carbon in the compound is a bridgehead carbon, or there is no hydrogen atom on the α-carbon, or both. [2]: A bicyclic acetylene alcohol compound according to [1] above, wherein the minimum number of carbon atoms constituting the ring is 7 or less. [3]: An addition-curable silicone composition, wherein the bicyclic acetylene alcohol compound according to [1] above or [2] above is contained as an addition-curable reaction inhibitor in an effective amount. [4]: ​​A thermally conductive addition-curable silicone composition, comprising: (A) a bicyclic acetylene alcohol having at least one aliphatic unsaturated hydrocarbon group per molecule and having a kinematic viscosity at 25°C of 60 to 100,000 mm ２ (B) at least one thermally conductive filler selected from the group consisting of metals, metal oxides, metal hydroxides, metal nitrides, metal carbides, and carbon allotropes: in an amount of 10 to 98 mass% based on the total composition, (C) an organohydrogenpolysiloxane having two or more silicon-bonded hydrogen atoms per molecule: in an amount sufficient to cause the composition to form a cured product, (D) a platinum group metal catalyst: in an effective amount, and (E) the bicyclic acetylene alcohol compound of [1] or [2] above: in an effective amount. [5]: The thermally conductive addition-curable silicone composition of [4] above, wherein component (B) is silver powder. [6]: The thermally conductive addition-curable silicone composition according to [4] or [5] above, characterized in that the thermally conductive addition-curable silicone composition further contains: (F) a phenolic compound represented by the following general formula (1A): in an amount of 0.01 to 10% by mass, based on the total mass of the composition: (In general formula (1A), R １represents a hydrogen atom, a halogen atom, a cyano group, or a hydroxyl group. Az represents a linear, branched, or cyclic hydrocarbon group having 1 to 20 carbon atoms and a valence of (ka+2), or a fluorinated hydrocarbon group, and —CH ２ - is -O-, -C(=O)-, or -Si(R ２ R ３ )- may be substituted. ２ , R ３ is a linear, branched, or cyclic alkyl group having 1 to 6 carbon atoms, or a phenyl group, and —CH ２ - is -O-, -C(=O)-, or -Si(CH ３ ) ２ -. Xf each independently represent a hydrogen atom, a halogen atom, a linear, branched, or cyclic monovalent hydrocarbon group having 1 to 10 carbon atoms which may be substituted with a fluorine atom, an alkoxy group having 1 to 10 carbon atoms which may be substituted with a fluorine atom, or an electron-withdrawing group. Z represents a single bond or an oxygen atom. Rings ZZ each independently represent an aromatic monocyclic or polycyclic ring having 3 to 20 carbon atoms. A carbon atom in ring ZZ may be substituted with a nitrogen atom, an oxygen atom, or a sulfur atom. ka represents an integer of 0 to 2. kb and kd represent 1 or 2. kc and ke represent integers of 0 to 2.) [7]: The thermally conductive addition-curable silicone composition of above [6], wherein component (F) is a phenol compound represented by the following general formula (1B): In the general formula (1B), Az′ represents a linear, branched, or cyclic hydrocarbon group having 1 to 19 carbon atoms and a valence of (ka′+2), or a fluorinated hydrocarbon group, and —CH ２ - is -O-, -C(=O)-, or -Si(R ２ R ３ )-. ka' represents 0 or 1. kb', kc', kd', and ke' represent 1 or 2. R １ , R ２ , R ３ is the same as above.)

[0115] The present invention is not limited to the above-described embodiments, which are merely examples, and anything that has substantially the same configuration as the technical idea described in the claims of the present invention and that provides similar effects is included within the technical scope of the present invention.

Claims

1. A bicyclic acetylene alcohol compound, characterized in that the carbon atom in said compound substituted with a hydroxyl group is a tertiary carbon atom bonded to an acetylene group, and the α-carbon in said compound is a bridgehead carbon, or there is no hydrogen atom on the α-carbon, or both.

2. The bicyclic acetylene alcohol compound according to claim 1, characterized in that the minimum number of carbon atoms constituting the ring is 7 or less.

3. An addition-curing silicone composition, comprising an effective amount of the bicyclic acetylene alcohol compound according to claim 1 or 2 as an addition-curing reaction inhibitor.

4. A thermally conductive addition-curable silicone composition, comprising: (A) at least one aliphatic unsaturated hydrocarbon group per molecule, and a kinetic viscosity at 25°C of 60 to 100,000 mm ２ 1. A thermally conductive addition-curable silicone composition comprising: (a) an organopolysiloxane having a structure represented by the general formula (I) and a structure represented by the general formula (I): (A) an organopolysiloxane having a structure represented by the general formula (I): (B) an organopolysiloxane having a structure represented by the general formula (I): (C) an organopolysiloxane having a structure represented by the general formula (I): (C) an organopolysiloxane having a structure represented by the general formula (I): (D) an effective amount of a platinum group metal catalyst; and (E) the bicyclic acetylene alcohol compound according to claim 1 or 2.

5. The thermally conductive addition-curable silicone composition according to claim 4, wherein component (B) is silver powder.

6. The thermally conductive addition-curable silicone composition according to claim 4, further comprising: (F) a phenol compound represented by the following general formula (1A): in an amount of 0.01 to 10 mass % based on the total mass of the composition: (In general formula (1A), R １ represents a hydrogen atom, a halogen atom, a cyano group, or a hydroxyl group. Az represents a linear, branched, or cyclic (ka+2)-valent hydrocarbon group having 1 to 20 carbon atoms, or a fluorinated hydrocarbon group, and the -CH ２ - is -O-, -C(=O)-, or -Si(R ２ R ３ )- may be substituted. ２ , R ３ is a linear, branched, or cyclic alkyl group having 1 to 6 carbon atoms, or a phenyl group, and the --CH ２ - is -O-, -C(=O)-, or -Si(CH ３ ) ２ - may be substituted. Each Xf independently represents a hydrogen atom, a halogen atom, a linear, branched, or cyclic monovalent hydrocarbon group having 1 to 10 carbon atoms which may be substituted with a fluorine atom, an alkoxy group having 1 to 10 carbon atoms which may be substituted with a fluorine atom, or an electron-withdrawing group. Z represents a single bond or an oxygen atom. Each ring ZZ independently represents an aromatic monocyclic or polycyclic ring having 3 to 20 carbon atoms. The carbon atom of the ring ZZ may be substituted with a nitrogen atom, an oxygen atom, or a sulfur atom. ka represents an integer of 0 to 2. kb and kd represent 1 or 2. kc and ke represent integers of 0 to 2.) 7. The thermally conductive addition-curable silicone composition according to claim 6, wherein the component (F) is a phenol compound represented by the following general formula (1B): In the general formula (1B), Az' represents a linear, branched, or cyclic hydrocarbon group having 1 to 19 carbon atoms and a valence of (ka'+2), or a fluorinated hydrocarbon group, and -CH ２ - is -O-, -C(=O)-, or -Si(R ２ R ３ ka' represents 0 or 1. kb', kc', kd', and ke' represent 1 or 2. R １ , R ２ , R ３ is the same as above.)

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