Thermally conductive curable silicone composition, cured product or gap filler obtained by curing said composition, two-part silicone composition set for obtaining said composition, and method for producing said composition

Abstract

A thermally conductive curable silicone composition containing components (a)-(g), wherein: component (a) is a linear organopolysiloxane compound having 1.5-2.0 alkenyl groups at the ends, component (b) is a thermally conductive filler, component (c) is an alkyltrialkoxysilane compound, component (d) is a condensation reaction catalyst, component (e) is a hydrosilylation reaction catalyst, component (f) is an organosilicon compound represented by general formula (1) (R1 and R2 are C1-4 alkyl groups, R3 is a hydrogen atom or a C1-8 alkyl group, X is a hydrogen atom or a C1-4 alkyl group, m is an integer of 0-8, and n is an integer of 3-8.), and (g) is an organopolysiloxane compound having 1.5 or more hydrosilyl groups; there are 0.5-10 mass parts of component (f) per 100 mass parts of component (a); there is 60-82 vol% of component (b) in the composition; there are 0.1-1.5 mass parts of component (c) per 100 mass parts of component (b); and the molar quantity of hydrosilyl groups in component (g) is 0.5-5.0 relative to the molar quantity of alkenyl groups in component (a).

Description

A thermally conductive curable silicone composition, a cured product or gap filler obtained by curing the composition, a two-component silicone composition set for obtaining the composition, and a method for manufacturing the composition.

[0001] The present invention relates to a thermally conductive curable silicone composition, a cured product or gap filler obtained by curing the composition, a two-component silicone composition set for obtaining the composition, and a method for manufacturing the composition.

[0002] As transportation vehicles such as automobiles, ships, and aircraft become more electrified, there is an increasing demand for higher capacity and higher output batteries to extend their range. As the current value increases with higher capacity and output of batteries, the amount of heat generated also increases. Therefore, the importance of thermally conductive materials (gap fillers, thermally conductive sheets, thermal grease, etc.) to efficiently transfer the heat generated by the battery to heat dissipation materials such as heat sinks is increasing. Gap fillers are adhesive thermally conductive filler materials that fill the gap between the battery and the heat dissipation material. They can be formed by applying or filling a slurry-like or paste-like curable composition containing a thermally conductive filler to the location where the gap filler is to be placed, and then subjecting it to a curing reaction.

[0003] As batteries become more high-capacity or higher-output, the degree of expansion and contraction (volume change) of batteries during charging and discharging is increasing. Furthermore, during the operation of a transport vehicle, the interior is subjected to continuous vibrations of varying magnitudes. Therefore, the gap filler described above requires high adhesion and flexibility that can continuously follow the large volume changes of the battery and withstand the shear forces and load changes associated with repeated vibrations.

[0004] For example, Patent Document 1 describes a two-component thermally conductive silicone composition prepared such that each component is present in a specific amount. The first liquid comprises (A) a diorganopolysiloxane having alkenyl groups bonded to silicon atoms, (D) an addition catalyst, (E) a thermally conductive filler, and (F) a condensation catalyst. The second liquid comprises (A) a diorganopolysiloxane having alkenyl groups bonded to silicon atoms, (B) a diorganopolysiloxane having hydrogen atoms bonded to silicon atoms, (C) an organosilicon compound having at least two groups selected from methoxy and ethoxy groups and having no hydrocarbon groups or vinyl groups with 3 or more carbon atoms, and (C-2) at least one selected from hydrolysates of the organosilicon compound (C-1), and (E) a thermally conductive filler. Patent Document 1 describes a method for forming a gap filler by mixing the first liquid and the second liquid to obtain a thermally conductive silicone composition, applying it to at least one of the substrates of the battery unit housing and the cooler, and then curing it. It also states that this gap filler has good storage stability, maintains good adhesion to the substrate even under vibrational conditions, and has excellent heat dissipation characteristics.

[0005] Patent No. 7368656

[0006] When the present inventors investigated the two-component thermal conductive silicone composition or gap filler described in Patent Document 1, they found that neither the adhesiveness nor the flexibility was sufficient to sustainably achieve efficient heat dissipation from high-capacity, high-output batteries installed in transport vehicles. In other words, when exposed to repeated expansion and contraction of the battery over a long period of time and repeated vibration, it became difficult to maintain sufficient conformability to the adherend such as the battery unit housing, and the gap filler may peel off from the adherend or suffer damage such as cracks or defects.

[0007] The object of the present invention is to provide a cured product (gap filler) that is resistant to peeling off and damage from the adherend even when repeatedly exposed to expansion, contraction, and vibration of the adherend, and that can sustainably exhibit highly efficient heat dissipation even when repeatedly driven while installed in a transport vehicle. Another object of the present invention is to provide a thermally conductive curable silicone composition suitable for forming the cured product, and a two-component silicone composition set for obtaining this composition.

[0008] The above problems of the present invention are solved by the following means: [1] A thermally conductive curable silicone composition, wherein the thermally conductive curable silicone composition contains the following components (a) to (g): (a) a linear organopolysiloxane compound having 1.5 to 2.0 alkenyl groups at the molecular chain ends and not having a hydrosilyl group; (b) a thermally conductive filler; (c) an alkyltrialkoxysilane compound; (d) a condensation reaction catalyst; (e) a hydrosilylation reaction catalyst; (f) an organosilicon compound represented by the following general formula (1); In the formula, R １ and R ２ Each of these independently represents an alkyl group having 1 to 4 carbon atoms. ３Each independently represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms. Each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. m is an integer from 0 to 8, and n is an integer from 3 to 8. (g) An organopolysiloxane compound having 1.5 or more hydrosilyl groups in the molecule and no alkenyl groups; The content of component (f) is 0.5 to 10 parts by mass per 100 parts by mass of component (a), the content of component (b) is 60 to 82 volume% in the thermally conductive curable silicone composition, the content of component (c) is 0.1 to 1.5 parts by mass per 100 parts by mass of component (b), and the ratio of the total molar amount of hydrosilyl groups in component (g) (Gm / Am) to the total molar amount of alkenyl groups in component (a) (Am) is 0.5 to 5.0, a thermally conductive curable silicone composition. [2] The thermally conductive curable silicone composition according to [1], wherein the thermally conductive curable silicone composition contains at least one of the following components (h-1) and (h-2): (h-1) a silicone resin having an alkenyl group; (h-2) hydrophobic silica; and the total content of each of the components (h-1) and (h-2) is 0.1 to 5 parts by mass per 100 parts by mass of the content of component (a). [3] The thermally conductive curable silicone composition according to [1] or [2], wherein the thermally conductive curable silicone composition contains the following component (i): (i) an alkenyltrialkoxysilane having 3 to 16 carbon atoms in the alkenyl group; and the content of component (i) is 0.1 to 3 parts by mass per 100 parts by mass of the content of component (a). [4] The thermally conductive curable silicone composition according to any one of [1] to [3], wherein component (b) comprises at least one of aluminum hydroxide and aluminum oxide, and the content of component (b) in the thermally conductive curable silicone composition is 67 to 73% by volume. [5] The thermally conductive curable silicone composition according to [4], wherein the proportion of aluminum hydroxide in component (b) is 70% by volume or more. [6] A cured product obtained by curing the thermally conductive curable silicone composition according to any one of [1] to [5]. [7] A gap filler comprising the cured product according to [6].[8] The gap filler according to [7] for application to batteries mounted on transport aircraft. [9] A two-component silicone composition set for obtaining the thermally conductive curable silicone composition according to any one of [1] to [5], comprising a first liquid containing component (e) but not component (g), and a second liquid containing component (g) but not component (e).

[10] The two-component silicone composition set according to [9], wherein the first liquid contains at least components (a) to (e), and the second liquid contains at least components (a) to (c), (f), and (g).

[11] A method for producing the thermally conductive curable silicone composition according to any one of [1] to [5], comprising mixing the first liquid and the second liquid of the two-component silicone composition set according to [9] or

[10] .

[12] A method for producing a thermally conductive curable silicone composition according to

[11] , comprising incorporating a mixture of component (b) and component (c) in the preparation of the first liquid and / or the second liquid.

[0009] In this invention, a numerical range represented using "~" means a range that includes the numbers written before and after "~" as the lower and upper limits, respectively.

[0010] The cured product (gap filler) of the present invention is resistant to peeling and damage even when repeatedly exposed to expansion, contraction, and vibration of the adherend, and can sustainably exhibit highly efficient heat dissipation even when repeatedly driven while installed in a transport vehicle. The thermally conductive curable silicone composition of the present invention can be used to obtain the above-mentioned cured product (gap filler) by subjecting this composition to a curing reaction. Furthermore, the two-component silicone composition set of the present invention can be used to obtain the thermally conductive curable silicone composition of the present invention by mixing the two components, and the above-mentioned cured product (gap filler) can be obtained by subjecting this composition to a curing reaction.

[0011] Preferred embodiments of the present invention will be described below, but the present invention is not limited to the embodiments described below other than those specified herein.

[0012] [Thermally Conductive Curable Silicone Composition] The thermally conductive curable silicone composition of the present invention (hereinafter also referred to as "the composition of the present invention") contains at least the following components (a) to (g) in specific amounts. The composition of the present invention may contain components other than the following components (a) to (g) as long as it does not impair the effects of the present invention. The composition of the present invention is in the state before the curing reaction proceeds, and therefore is normally a fluid dispersion at room temperature (25°C), in which at least the thermally conductive filler is dispersed as solid particles. The components contained in or that may be contained in the composition of the present invention will be described below.

[0013] <Component (a): A linear organopolysiloxane compound having 1.5 to 2.0 alkenyl groups at the molecular chain ends and lacking hydrosilyl groups> Component (a) is a linear organopolysiloxane having 1.5 to 2.0 alkenyl groups at the molecular chain ends and lacking hydrosilyl groups. "Linear" means that the linking structure by siloxane bonds is linear, and "molecular chain ends" means the ends of a straight chain. Therefore, there are two types of structures in which a single molecule of a linear organopolysiloxane compound has an alkenyl group at the molecular chain ends: a structure with an alkenyl group at one end (in this case, there is one alkenyl group in the molecule) and a structure with alkenyl groups at both ends (in this case, there are two alkenyl groups in the molecule). "Having 1.5 to 2.0 alkenyl groups at the molecular chain ends" means that the total number of alkenyl groups at the molecular chain ends of all molecules of the "linear organopolysiloxane having alkenyl groups at the molecular chain ends but not hydrosilyl groups" contained in the composition of the present invention (all molecules constituting component (a)) is divided by the total number of such molecules, and the resulting value (i.e., the average value) is 1.5 to 2.0. In component (a), the number of alkenyl groups at the molecular chain ends is preferably 1.6 to 2.0, more preferably 1.7 to 2.0, and also preferably 1.8 to 2.0. Furthermore, the linear organopolysiloxane, which is component (a), has 1.5 to 2.0 alkenyl groups at the end of the molecular chain and does not have a hydrosilyl group, preferably has 1.5 to 50 alkenyl groups in the molecule (the whole molecule), more preferably 1.6 to 20, even more preferably 1.7 to 10, even more preferably 1.8 to 6, and also preferably 2 to 4. The number of alkenyl groups in this molecule is also an average value for the entire component (a). Hereafter, individual molecules of the linear organopolysiloxane compound constituting component (a) will be referred to as "(a) linear organopolysiloxane molecule".

[0014] (a) Linear organopolysiloxane molecules are diorganosiloxy units (*-Si(R) ２A linear structure with a main chain consisting of repeating -O-* (where R is an organic group and * is a bond), and one or both ends of this main chain are alkenyl dialkylsiloxy groups (-Si(alkenyl)(alkyl) ２ A linear diorganopolysiloxane molecule is preferred, where "alkenyl" is an alkenyl group and "alkyl" is an alkyl group. In this case, the number of alkenyl groups at the end of the molecular chain (average value above) of component (a), which is an aggregate of linear organopolysiloxane molecules, is 1.5 to 2.0 as described above. The above organic group R is preferably a hydrocarbon group having 1 to 18 carbon atoms. Preferred specific examples of hydrocarbon groups having 1 to 18 carbon atoms include alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-, pentyl, neopentyl, hexyl, 2-ethylhexyl, heptyl, octyl, nonyl, decyl, and dodecyl groups; cycloalkyl groups such as cyclopentyl, cyclohexyl, and cycloheptyl groups; aryl groups such as phenyl, tolyl, xylyl, biphenyl, and naphthyl groups; aralkyl groups such as benzyl, phenylethyl, phenylpropyl, and methylbenzyl groups; and groups in which some or all of the hydrogen atoms in these hydrocarbon groups are substituted with halogen atoms, cyano groups, etc. (for example, chloromethyl, 2-bromoethyl, 3,3,3-trifluoropropyl, 3-chloropropyl, and cyanoethyl groups). The above organic group R is particularly preferably a methyl group. It is also preferable that part of the above organic group R is an alkenyl group.

[0015] (a) In the linear organopolysiloxane molecule, alkenyl groups may be bonded not only to the ends of the molecular chain, but also to at least some of the Si that constitute the siloxane bonds of the main chain, as described above. Using the (a) linear organopolysiloxane molecule which has crosslinking points in addition to the ends in this way results in a denser three-dimensional network of the resulting cured product, which is advantageous in improving shear adhesion strength. Conversely, if no alkenyl groups are bonded to the Si that constitute the siloxane bonds of the main chain, there is an advantage in that the flexibility of the resulting cured product is increased because there are fewer crosslinking points. (a) In the linear organopolysiloxane molecule, each siloxane unit constituting this molecule may be the same or different.

[0016] The viscosity of component (a) ((a) an aggregate of linear organopolysiloxane molecules) is not particularly limited, and for example, a viscosity of 10 to 10,000 mPa·s can be used. A viscosity of 20 to 5,000 mPa·s is preferred, and 30 to 2,000 mPa·s is more preferred. By setting the viscosity within the above range, the fluidity of the resulting thermally conductive curable silicone composition can be sufficiently ensured, resulting in excellent discharge properties and increased productivity of the cured product (gap filler). Furthermore, by setting the viscosity within the above range, the flexibility of the cured product of the thermally conductive curable silicone composition tends to be increased.

[0017] The alkenyl group in component (a) preferably has 2 to 10 carbon atoms, more preferably 2 to 8, even more preferably 2 to 6, and even more preferably 2 to 4 carbon atoms. Preferred specific examples of this alkenyl group include vinyl, allyl, propenyl, isopropenyl, butenyl, isobutenyl, hexenyl, and cyclohexenyl groups, with vinyl being particularly preferred.

[0018] <Component (b) Thermally conductive filler> Component (b) is a fine particle component that contributes to improving the thermal conductivity of the resulting cured product. For example, any thermally conductive filler used in existing gap fillers can be used as component (b) without any particular limitations. In the composition of the present invention, the content of component (b) is 60 to 82 volume%, more preferably 63 to 77 volume%, and even more preferably 67 to 73 volume%.

[0019] Examples of thermally conductive fillers constituting component (b) include at least one of the following: metals, metal oxides, metal hydroxides, metal carbonates, metal nitrides, and metal carbides. When curing the composition of the present invention to form a gap filler for use in transport aircraft batteries (battery cells and battery modules), excellent thermal conductivity as well as insulating properties are required. Therefore, when considering a gap filler for use in transport aircraft batteries, it is preferable to use ceramic particles or the like rather than conductive particles composed of metal itself (carrier metal or alloy).

[0020] Examples of materials that make up ceramic particles include: As metal oxides, for example, aluminum oxide, zinc oxide, magnesium oxide, titanium oxide, silicon oxide, beryllium oxide, etc. As metal hydroxides, for example, aluminum hydroxide, magnesium hydroxide, etc. As metal carbonates, for example, magnesium carbonate, calcium carbonate, etc. As metal nitrides, for example, aluminum nitride, silicon nitride, boron nitride, etc. As metal carbides, for example, boron carbide, titanium carbide, silicon carbide, etc.

[0021] Examples of materials for conductive, thermally conductive fillers include graphite, other types of graphite, metals such as aluminum, copper, nickel, and silver, or alloys of two or more metals, and mixtures thereof.

[0022] In particular, component (b) preferably contains at least one of aluminum oxide, aluminum hydroxide, magnesium oxide, magnesium hydroxide, zinc oxide, aluminum nitride, and boron nitride, and more preferably contains at least one of aluminum hydroxide and aluminum oxide. Silicone compositions using thermally conductive fillers with high Mohs hardness may cause wear on equipment during mixing and coating; therefore, from this viewpoint, it is preferable to use thermally conductive fillers with low Mohs hardness. For example, aluminum hydroxide, which has a low specific gravity, is inexpensive, and has low Mohs hardness, is suitable as component (b).

[0023] More specifically, a preferred form of component (b) is to include at least one of aluminum hydroxide and aluminum oxide, and the content of component (b) in the thermally conductive curable silicone composition is preferably 60 to 82% by volume, and more preferably 67 to 73% by volume. By adjusting component (b) in the composition in this way, the thermal conductivity of the resulting cured product can be more effectively enhanced while ensuring sufficient flexibility. Furthermore, it is preferable that component (b) includes aluminum hydroxide, and that the proportion of aluminum hydroxide in component (b) is 70% by volume or more. By including component (b) adjusted in this way in the composition, the adhesiveness can be further enhanced.

[0024] The particle size of the thermally conductive filler constituting component (b) is not particularly limited, but the particle size of the filler as a whole constituting component (b) is preferably 1 to 300 μm, more preferably 10 to 200 μm, even more preferably 20 to 150 μm, and even more preferably 25 to 120 μm. In this invention, when simply referred to as "particle size," it means the median diameter based on volume. By using such a particle size range, the fluidity of the composition is further enhanced, and even when the composition is applied thinly, streaking and roughness in the coating film are less likely to occur. It is also preferable to use a combination of multiple thermally conductive fillers with different particle sizes and shapes. By doing so, the filling rate of the thermally conductive filler in the composition or cured product is further increased, and the thermal conductivity of the cured product can be further enhanced. As an example, a configuration in which thermally conductive fillers with particle sizes of 100 μm, 10 μm, or 1 μm are used in combination can be mentioned. In this combination, the particle size (volume-based median diameter) of the filler as a whole constituting component (b) is preferably 10 to 90 μm, and more preferably 20 to 80 μm.

[0025] <Component (c) Alkyltrialkoxysilane compound> The alkyltrialkoxysilane compound of component (c) modifies the surface of the thermally conductive filler of component (b) by interacting with it (for example, by undergoing a dehydration condensation reaction with the hydroxyl groups on the surface). This improves the dispersibility of the thermally conductive filler, suppresses the increase in viscosity of the composition of the present invention, and also suppresses the phenomenon of the thermally conductive filler settling over time, thereby improving the handling properties of the composition. For example, in the preparation of the composition or composition set of the present invention, the interaction between components (b) and (c) can be further enhanced by pre-mixing components (b) and (c) while heating and reducing the pressure as necessary. Furthermore, in the preparation of the composition or composition set of the present invention, the surface modification efficiency of the thermally conductive filler, which is component (b), can be further enhanced by incorporating component (c) in a dissolved state in a solvent. In order to ensure that the thermally conductive filler is sufficiently and uniformly dispersed in the composition of the present invention, and to provide the composition with sufficient fluidity, as well as to ensure sufficient interaction between the thermally conductive filler of component (b) and component (f) described later, the content of component (c) in the composition of the present invention is 0.1 to 1.5 parts by mass per 100 parts by mass of component (b).

[0026] The alkoxy group of the alkyltrialkoxysilane compound constituting component (c) preferably has 1 to 10 carbon atoms, more preferably 1 to 6, even more preferably 1 to 3, and particularly preferably a methyl or ethyl group. Furthermore, the alkyl group of the alkyltrialkoxysilane compound preferably has 1 to 30 carbon atoms, more preferably 2 to 20, even more preferably 3 to 18, even more preferably 4 to 16, even more preferably 5 to 12, and particularly preferably 6 to 10. When the alkyl group has 3 or more carbon atoms, a linear chain is preferred.

[0027] Preferred specific examples of alkyltrialkoxysilane compounds constituting component (c) include methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, isopropyltrimethoxysilane, isopropyltriethoxysilane, n-hexyltrimethoxysilane, n-hexyltriethoxysilane, n-octyltrimethoxysilane, n-octyltriethoxysilane, n-decyltrimethoxysilane, n-decyltriethoxysilane, n-octadecyltrimethoxysilane, and n-octadecyltriethoxysilane.

[0028] <Component (d) Condensation Reaction Catalyst> By containing the condensation reaction catalyst component (d) of the composition of the present invention, sufficient adhesion to the adherend can be achieved even under mild curing reaction conditions such as room temperature. Typically, the surface of adherends such as metal substrates like aluminum and organic resin substrates like PET has condensation-reactive groups such as hydroxyl groups, alkoxy groups, and ester groups. The condensation reaction catalyst component (d) promotes the condensation reaction between the condensation-reactive groups on the adherend surface and the alkoxy groups, hydroxyl groups, etc., present in the components constituting the composition of the present invention. The condensation reaction catalyst that can be used as component (d) is known, and a wide range of known catalysts that function as this type of condensation reaction catalyst can be applied. For example, the condensation catalyst described as component (F) in Japanese Patent Publication No. 7368656 is suitable as the condensation reaction catalyst component (d) to be incorporated into the composition of the present invention. For example, one or more compounds containing metal atoms selected from magnesium, aluminum, titanium, chromium, iron, cobalt, nickel, copper, zinc, zirconium, tungsten, and bismuth (metal compounds) can be used as component (d). Examples of such metal compounds include metal complex compounds. Ligands constituting the above metal complex compounds include organic acids such as octic acid, lauric acid, and stearic acid; alkoxides such as propoxide and butoxide; catechol; crown ethers; polycarboxylic acids; hydroxy acids; diketones such as ethyl acetacetate; keto acids; and the like. Multiple types of ligands may be bonded to a single metal atom. Among these, complex compounds containing titanium, zirconium, or aluminum are preferred.

[0029] Preferred specific examples of the condensation reaction catalyst for component (d) include, as alkoxy group-containing titanium compounds (titanium alkoxides), titanium tetramethoxide, titanium tetraethoxide, titanium tetraallyl oxide, titanium tetra-n-propoxide, titanium tetraisopropoxide, titanium tetra-n-butoxide, titanium tetraisobutoxide, titanium tetra-s-butoxide, titanium tetra-t-butoxide, titanium tetra-n-pentyl oxide, titanium tetracyclopentyl oxide, titanium tetrahexyl oxide, titanium tetracyclohexyl oxide, titanium tetrabenzyl oxide, titanium tetraoctyl oxide, titanium tetrakis(2-ethylhexyl oxide), titanium tetradecyl oxide, and titanium tetrad Examples include decyl oxide, titanium tetrastearyl oxide, titanium tetrabutoxide dimer, titanium tetrakis(8-hydroxyoctyl oxide), titanium diisopropoxide bis(2-ethyl-1,3-hexanediolato), titanium bis(2-ethylhexyloxy)bis(2-ethyl-1,3-hexanediolato), titanium tetrakis(2-methoxyethoxide), titanium tetrakis(2-ethoxyethoxide), titanium butoxide trimethoxide, titanium dibutoxide dimethoxide, titanium butoxide triethoxide, titanium dibutoxide diethoxide, titanium butoxide triisopropoxide, titanium dibutoxide diisopropoxide, and titanium tetraphenoxide.

[0030] Examples of the titanium chelate compound include titanium dimethoxy bis(ethyl acetoacetate), titanium dimethoxide bis(acetylacetonate), titanium diethoxy bis(ethyl acetoacetate), titanium diethoxide bis(acetylacetonate), titanium diisopropoxy bis(ethyl acetoacetate), titanium diisopropoxy bis(methyl acetoacetate), titanium diisopropoxy bis(t-butyl acetoacetate), titanium diisopropoxy bis(methyl-3-oxo-4,4-dimethylhexanoate), titanium diisopropoxy bis(acetylacetonate), titanium di-n-butoxy bis(ethyl acetoacetate), titanium di-n-butoxy bis(acetylacetonate), titanium diisobutoxy bis(acetylacetonate), titanium di-t-butoxy bis(ethyl acetoacetate), titanium di-t-butoxy bis(acetylacetonate), titanium tetrakis(ethyl acetoacetate), titanium tetrakis(acetylacetonate), titanium bis(trimethylsiloxy) bis(ethyl acetoacetate), and titanium bis(trimethylsiloxy) bis(acetylacetonate).

[0031] Examples of zirconium compounds containing alkoxy groups include zirconium tetramethoxide, zirconium tetraethoxide, zirconium tetraallyloxide, zirconium tetra-n-propoxide, zirconium tetraisopropoxide, zirconium tetra-n-butoxide, zirconium tetraisobutoxide, zirconium tetra-s-butoxide, zirconium tetra-t-butoxide, zirconium tetra-n-pentyloxide, zirconium tetracyclopentyloxide, zirconium tetrahexyloxide, zirconium tetracyclohexyloxide, zirconium tetrabenzyloxide, and zirconium tetra Examples include traoctyl oxide, zirconium tetrakiss (2-ethylhexyl oxide), zirconium tetradecyl oxide, titanium tetradodecyl oxide, zirconium tetrastearyl oxide, zirconium tetrakiss (2-methoxyethoxide), zirconium tetrakiss (2-ethoxyethoxide), zirconium butoxide trimethoxide, zirconium dibutoxide dimethoxide, zirconium butoxide triethoxide, zirconium dibutoxide diethoxide, zirconium butoxide triisopropoxide, zirconium dibutoxide diisopropoxide, and zirconium tetraphenoxide.

[0032] Examples of zirconium chelate compounds include zirconium tetra(acetylacetonate), zirconium dimethoxybis(ethyl acetoacetate), zirconium dimethoxybis(acetylacetonate), zirconium diethoxybis(ethyl acetoacetate), zirconium diethoxybis(acetylacetonate), zirconium diethoxybis(ethyl acetoacetate), zirconium diisopropoxybis(ethyl acetoacetate), zirconium triisopropoxy(ethyl acetoacetate), zirconium tri-n-butoxide(ethyl acetoacetate), zirconium diisopropoxybis(methyl acetoacetate), zirconium diisopropoxybis(t-butyl acetoacetate), zirconium diisopropoxybis(acetylacetonate), zirconium di-n-butoxybis(ethyl acetoacetate), zirconium di-n-butoxybis(acetylacetonate), zirconium diisobutoxybis(ethyl acetoacetate), zirconium diisobutoxybis(acetylacetonate), zirconium di-t-butoxybis(ethyl acetoacetate), zirconium di-t-butoxybis(acetylacetonate), zirconium isopropoxytri(ethyl acetoacetate), zirconium-n-butoxidetri(ethyl acetoacetate), zirconium tetrakis(ethyl acetoacetate), and zirconium tetrakis(acetylacetonate).

[0033] Examples of acylates containing zirconium include zirconium octylate and zirconium stearate.

[0034] Examples of alkoxy group-containing aluminum compounds include aluminum trimethoxide, aluminum triethoxide, aluminum triallyl oxide, aluminum tri-n-propoxide, aluminum triisopropoxide, aluminum tri-n-butoxide, aluminum triisobutoxide, aluminum tri-s-butoxide, aluminum tri-t-butoxide, aluminum tri-n-pentyl oxide, aluminum tricyclopentyl oxide, aluminum tridecyl oxide, aluminum tridodecyl oxide, aluminum tristearyl oxide, aluminum tris(2-methoxyethoxide), aluminum tris(2-ethoxyethoxide), aluminum butoxide dimethoxide, aluminum methoxide dibutoxide, aluminum butoxide diethoxide, aluminum ethoxide dibutoxide, aluminum butoxide diisopropoxide, aluminum isopropoxide dibutoxide, and aluminum triphenoxide.Examples of aluminum chelating compounds include aluminum methoxybis(ethyl acetate), aluminum methoxidebis(acetylacetonate), aluminum ethoxybis(ethyl acetate), aluminum ethoxidebis(acetylacetonate), aluminum isopropoxybis(ethyl acetate), aluminum isopropoxybis(methyl acetate), aluminum isopropoxybis(t-butyl acetate), aluminum dimethoxide(ethyl acetate), aluminum dimethoxy(acetylacetonate), aluminum diethoxy(ethyl acetate), aluminum diethoxy(acetylacetonate), aluminum diisopropoxy(ethyl acetate), aluminum diisopropoxy(methyl acetate), and aluminum diisopropoxy(t- Examples include butylacetate, aluminum diisopropoxy(methylacetate), aluminum isopropoxybis(acetylacetonate), aluminum-n-butoxybis(ethylacetate), aluminum-n-butoxybis(acetylacetonate), aluminum isobutoxybis(ethylacetate), aluminum isobutoxybis(acetylacetonate), aluminum-t-butoxybis(ethylacetate), aluminum-t-butoxybis(acetylacetonate), aluminum-2-ethylhexoxybis(ethylacetate), aluminum tris(ethylacetate), aluminum tris(acetylacetonate), and aluminum(acetylacetonate)bis(ethylacetate).

[0035] In the composition of the present invention, the content of component (d) only needs to be in an amount that functions as a catalyst (so-called catalytic amount). For example, the content of component (d) can be 0.1 to 10 parts by mass per 100 parts by mass of component (a), preferably 0.2 to 8 parts by mass, more preferably 0.3 to 6 parts by mass, even more preferably 0.4 to 4 parts by mass, and also preferably 0.6 to 3 parts by mass. Note that if component (d) is in the form of a catalytically active substance supported on a solid phase (supported catalyst), the content of component (d) shall be the total content of the supported catalyst. The same applies to component (e) described below.

[0036] <Component (e) Hydrosilylation Reaction Catalyst> The hydrosilylation reaction catalyst for component (e) is a component that promotes the hydrosilylation reaction (addition reaction) that occurs between the alkenyl group of component (a) and the hydrosilyl group of component (g). Hydrosilylation reaction catalysts that can be used as component (e) are known, and a wide range of known catalysts that function as hydrosilylation reaction catalysts can be applied. For example, the addition catalyst described as component (D) in Japanese Patent Publication No. 7368656 is suitable as the hydrosilylation reaction catalyst for component (e) to be incorporated into the composition of the present invention. For example, platinum group metals such as platinum, rhodium, palladium, osmium, iridium, and ruthenium are suitable as component (e). These metals can also constitute component (e) of the composition of the present invention when immobilized on a particulate carrier material (e.g., activated carbon, aluminum oxide, silicon oxide). Furthermore, platinum compounds such as platinum halides, platinum-olefin complexes, platinum-alcohol complexes, platinum-alkoxide complexes, platinum-vinylsiloxane complexes, dicyclopentadiene-platinum dichloride, cyclooctadiene-platinum dichloride, and cyclopentadiene-platinum dichloride can be used as component (e). Also, from the viewpoint of reducing costs, metal compound catalysts other than platinum group metals may be used as component (e). For example, iron-carbonyl complex catalysts, iron catalysts having a cyclopentadienyl group as a ligand, iron catalysts having a terpyridine ligand or a terpyridine ligand and a bistrimethylsilylmethyl group, iron catalysts having a bisiminopyridine ligand, iron catalysts having a bisiminoquinoline ligand, iron catalysts having an aryl group as a ligand, iron catalysts having a cyclic or acyclic olefin group having an unsaturated group, and iron catalysts having a cyclic or acyclic olefinyl group having an unsaturated group are suitable as component (e). In addition, cobalt catalysts, vanadium catalysts, ruthenium catalysts, iridium catalysts, samarium catalysts, nickel catalysts, and manganese catalysts can also be used as component (e).

[0037] In the composition of the present invention, the content of component (e) may be used in an amount that functions as a catalyst (so-called catalytic amount). For example, with respect to 100 parts by mass of the content of component (a), the content of component (e) is preferably 0.001 to 3 parts by mass, more preferably 0.01 to 2 parts by mass, and still more preferably 0.1 to 1 part by mass.

[0038] <Component (f): Organosilicon compound represented by general formula (1)> Component (f) is an organosilicon compound represented by the following general formula (1).

[0039]

[0040] In the formula, R １ and R ２ each independently represent an alkyl group having 1 to 4 carbon atoms. R ３ each independently represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms. X each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. m is an integer from 0 to 8, and n is an integer from 3 to 8.

[0041] Component (f) is a component that enhances the adhesiveness between the substrate to which the composition of the present invention is applied (for example, a battery cell, a battery module, a heat sink, etc.) and the cured product obtained by curing the composition of the present invention applied on the substrate.

[0042] The organosilicon compound of component (f) has one trialkoxysilyl group (—Si(OR １ ) ３ ) in the molecule, and this trialkoxysilyl group undergoes hydrolysis in the presence of a condensation catalyst to generate a silanol group. The generated silanol group forms a hydrogen bond or a bond by a dehydration reaction with, for example, a hydroxyl group present on the surface of the substrate. Further, the organosilicon compound of component (f) has at least one hydrosilyl group (a group in which a hydrogen atom is directly bonded to a ring-constituting silicon atom), and this hydrosilyl group undergoes an addition reaction with the alkenyl group of component (a) in the presence of a hydrosilylation catalyst to form a crosslinked structure. Due to these reaction mechanisms, the adhesiveness between the composition of the present invention or its cured product and the substrate is improved. Also, component (f) has a medium-chain alkylene group having 3 to 8 carbon atoms (—(CH ２ ) ｎA substructure exists. The presence of this substructure gives chemical structural flexibility to component (f), which functions as a crosslinking agent connecting the substrate surface with the thermally conductive filler and polysiloxane structure of component (b). As a result, flexibility is imparted to the adhesive interface or its vicinity in the cured product formed by the curing of the composition of the present invention. Therefore, even if the adhesive is subjected to significant distortion due to the expansion and contraction of the battery or vibrations during driving, the adhesive is less likely to be damaged, and good adhesion can be maintained over a long period of time.

[0043] The organosilicon compound of component (f) has three Rs in general formula (1). １ Each of these is an alkyl group having 1 to 4 carbon atoms. When the number of carbon atoms exceeds 5, the efficiency of the condensation reaction decreases, leading to a decrease in adhesive strength. Also, there are four R's. ２ The reason why each of these is independently an alkyl group having 1 to 4 carbon atoms (a lower alkyl group) is to ensure a sufficient number of reactive groups (trialkoxysilyl group and hydrosilyl group) per unit weight to enhance adhesion. ３ The same applies to the reasons for limiting the number of carbon atoms when X is an alkyl group, and for limiting the number of m and n atoms to 8 or less. １ ~R ３ The alkyl groups that can be taken as X are preferably a methyl group or an ethyl group, and more preferably a methyl group. m is preferably 1 to 6, more preferably 1 to 4, and even more preferably 2 or 3.

[0044] When the composition of the present invention is cured, in order to achieve sufficient adhesive strength to substrates such as battery cells, battery modules, and heat sinks while also sufficiently increasing the flexibility of the cured product, the content of component (f) is set to 0.5 to 10 parts by mass per 100 parts by mass of component (a). The content of component (f) is preferably 0.6 to 9 parts by mass, more preferably 0.7 to 8 parts by mass, even more preferably 0.8 to 7 parts by mass, even more preferably 0.9 to 6 parts by mass, and particularly preferably 1 to 5 parts by mass, per 100 parts by mass of component (a).

[0045] <Component (g): An organopolysiloxane compound having 1.5 or more hydrosilyl groups in the molecule and lacking alkenyl groups> Component (g) is an organopolysiloxane compound having 1.5 or more hydrosilyl groups in the molecule and lacking alkenyl groups. "Having 1.5 or more hydrosilyl groups in the molecule" means that the total number of hydrosilyl groups in all molecules of the "organopolysiloxane having hydrosilyl groups in the molecule and lacking alkenyl groups" contained in the composition of the present invention (all molecules constituting component (g)) divided by the total number of such molecules (i.e., the average value) is 1.5 or more. Here, "hydrosilyl group" means a functional group in which a hydrogen atom is directly bonded to a silicon atom. In the present invention, the number of "hydrosilyl groups" is not the number of hydrogen atoms directly bonded to the silicon atom, but the number of siloxane units having hydrosilyl groups. Therefore, -SiH(R)-O-(R: substituent, preferably an organic group), -SiH ２ -O-, -SiH ２ (R), SiH(R) ２ , -SiH ３ Each of these is a siloxane unit, and the number of "hydrosilyl groups" is counted as one. In the present invention, it is preferable that the "hydrosilyl group" has one hydrogen atom directly bonded to a silicon atom, and that an organic group is bonded to the remaining bonds of the silicon atom that do not constitute a siloxane bond. This organic group is preferably an alkyl group or an aryl group, and more preferably an alkyl group. This alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 8, even more preferably 1 to 6, even more preferably 1 to 4, and even more preferably a methyl group or an ethyl group. Furthermore, the aryl group is preferably a phenyl group.

[0046] Component (g) is preferably an organopolysiloxane compound (organohydrogenpolysiloxane) having 1.5 to 50 hydrosilyl groups in the molecule, more preferably 1.6 to 20 hydrosilyl groups, even more preferably 1.7 to 10, even more preferably 1.8 to 6, and even more preferably 2 to 4.

[0047] The viscosity of component (g) (meaning the viscosity of the aggregate of organopolysiloxane molecules constituting component (g). The viscosity of component (g) is related to the degree of polymerization of the organopolysiloxane molecules constituting component (g)) is not particularly limited. For example, the viscosity of component (g) can be 10 to 10,000 mPa·s at 25°C. Component (g) is a component that acts as a curing agent for curing the composition of the present invention. Within the organopolysiloxane molecule constituting component (g), the location of the hydrosilyl group is not particularly limited. For example, a structure in which hydrogen atoms are directly bonded to silicon atoms at both ends of a linear diorganopolysiloxane molecule linked by siloxane bonds is preferred as the molecular structure of the organopolysiloxane constituting component (g). In this case, both ends are the above-mentioned -SiH(R) ２ It is preferable that the structure is such that one hydrogen atom is directly bonded to a silicon atom, and organic groups are bonded to the remaining two bonds. In the organopolysiloxane molecule constituting component (g), the amount of hydrosilyl groups is preferably 0.01 to 10.0 mmol / g, more preferably 0.05 to 5.0 mmol / g, and even more preferably 0.5 to 2.0 mmol / g, from the viewpoint of giving the composition of the present invention sufficient strength and displacement-following ability for practical purposes. Preferred specific examples of the organopolysiloxane molecule (organohydrogenpolysiloxane) constituting component (g) include, for example, methylhydrogenpolysiloxane, dimethylsiloxane / methylhydrogensiloxane copolymer, methylphenylsiloxane / methylhydrogensiloxane copolymer, and cyclic methylhydrogenpolysiloxane. As component (g), one type of organohydrogenpolysiloxane may be used, or two or more types of organohydrogenpolysiloxane may be used. In particular, dimethylpolysiloxane with dimethylhydrosilyl groups at both ends (the structure at both ends is -SiH(CH)) ３ ) ２ Dimethylpolysiloxane is preferred as component (g).

[0048] In the composition of the present invention, the ratio (Gm / Am) of the total molar amount (Gm) of hydrosilyl groups in component (g) to the total molar amount (Am) (synonymous with the number of alkenyl groups in component (a)) is 0.5 to 5.0. By setting the ratio of components (a) to (g) in this way, the composition of the present invention can be cured to form a three-dimensional network while also providing a suitable degree of flexibility. As a result, for example, even if the adhesive portion between the gap filler formed by curing the composition of the present invention and the battery cell or battery module as a substrate experiences significant strain due to the expansion and contraction of the battery or vibrations caused by driving, the gap filler is less likely to be damaged, such as cracks, defects, or peeling. The above ratio (Gm / Am) is more preferably 0.5 to 3.0, and even more preferably 0.8 to 1.4.

[0049] <Component (h-1): Silicone Resin Having an Alkenyl Group> The composition of the present invention may include a silicone resin having an alkenyl group as component (h-1). "Silicone resin" means silicone having a three-dimensional crosslinked structure. Silicone resin generally has at least one component selected from monofunctional component (M), difunctional component (D), trifunctional component (T), and tetrafunctional component (Q), and has a three-dimensional crosslinked structure by including at least one of the trifunctional component (T) and the tetrafunctional component (Q). When the composition of the present invention includes component (h-1), it is preferable that component (h-1) includes a silicone resin having a monofunctional component (M) and a tetrafunctional component (Q).

[0050] The silicone resin constituting component (h-1) preferably contains 0.1 to 10% by mass of alkenyl groups per molecule, more preferably 0.5 to 5% by mass, and even more preferably 1 to 3% by mass. The number of carbon atoms in the alkenyl group is preferably 2 to 10, more preferably 2 to 8, even more preferably 2 to 6, even more preferably 2 to 4, and even more preferably vinyl or allyl groups.

[0051] By including component (h-1) in the composition of the present invention, the mechanical strength of the resulting cured product is increased, and stronger adhesive force can be achieved. When the composition of the present invention contains component (h-1), it is preferable to determine the content of component (h-1) in the composition by taking into consideration the content of component (h-2), as described below.

[0052] Component (h-1) can be dissolved in component (a) by pre-mixing it with component (a) and heating it as needed. Therefore, it can be incorporated into the composition of the present invention without increasing its viscosity.

[0053] <Component (h-2) Hydrophobic Silica> The composition of the present invention may contain hydrophobic silica as component (h-2). By containing component (h-2) in the composition of the present invention, the mechanical strength of the cured product after the curing reaction can be increased, and the adhesion to the substrate can also be further improved.

[0054] The hydrophobic silica constituting component (h-2) can be obtained by treating the surface of fine silica powder, such as fumed silica, precipitated silica, or calcined silica, with an organic polysilazane compound (preferably an organic disilazane compound, e.g., hexamethyldisilazane), an organic silane compound (e.g., dimethyldichlorosilane), or a diorganopolysiloxane compound (e.g., dimethylpolysiloxane) to make it hydrophobic.

[0055] The hydrophobic silica constituting component (h-2) preferably has a volume-based median diameter of 1 to 100 nm, and more preferably 5 to 40 nm, in the aggregate of all particles constituting component (h-2). Commercially available hydrophobic silica can be used for component (h-2). Examples include AEROSIL90, 200, 300, R972, R974, or R976 (all manufactured by Evonik).

[0056] When the composition of the present invention contains component (h-2), it is preferable that its content be determined considering the content of component (h-1). That is, with respect to 100 parts by mass of component (a), the total content of components (h-1) and (h-2) is preferably 0.1 to 5 parts by mass, may also be 0.2 to 4 parts by mass, may also be 0.4 to 3 parts by mass, and may also be 0.6 to 3 parts by mass. Here, "total content of components (h-1) and (h-2)" means the content of component (h-1) if the composition of the present invention contains component (h-1) but not component (h-2), the content of component (h-2) if it does not contain component (h-1) but contains component (h-2), and the total amount of components (h-1) and (h-2) if it contains both component (h-1) and component (h-2).

[0057] <Component (i) Alkenyltrialkoxysilane having 3 to 16 carbon atoms in the alkenyl group> The composition of the present invention may contain an alkenyltrialkoxysilane having 3 to 16 carbon atoms in the alkenyl group as component (i). By containing component (i) in the composition of the present invention, it is possible to further increase the adhesive strength of the composition of the present invention or its cured product.

[0058] The alkenyl group of the alkenyltrialkoxysilane constituting component (i), having 3 to 16 carbon atoms, preferably has 4 to 14 carbon atoms, and more preferably 5 to 12 carbon atoms. A linear alkenyl group is preferred. The alkoxy group of the alkenyltrialkoxysilane constituting component (i), having 3 to 16 carbon atoms, preferably has 1 to 10 carbon atoms, more preferably 1 to 8, even more preferably 1 to 6, even more preferably 1 to 4, and a methyl group or an ethyl group is particularly preferred.

[0059] Preferred specific examples of alkenyltrialkoxysilanes having 3 to 16 carbon atoms that constitute component (i) include 7-octenyltrimethoxysilane, 7-octenyltriethoxysilane, 4-pentenyltrimethoxysilane, and 11-dodecenyltrimethoxysilane.

[0060] Component (i) can form primary bonds or hydrogen bonds with hydroxyl groups present on the surface of the substrate, for example, and at the same time react with components (b), (g), etc. to act as a crosslinking agent, contributing to improved adhesive strength.

[0061] When the composition of the present invention contains component (i), the content of component (i) in the composition of the present invention is preferably 0.1 to 3 parts by mass per 100 parts by mass of component (a). By setting the content within this range, it is possible to further increase the adhesive strength while ensuring sufficient flexibility of the cured product obtained by curing the composition of the present invention.

[0062] <Other Components> The composition of the present invention may contain components other than the above components (a) to (i), to the extent that it does not impair the desired effect. Examples of such components include compounds having a triple bond between carbon atoms, such as 1-ethynyl-1-cyclohexanol, as a curing retarder; colorants such as pigments and dyes; reinforcing agents such as silica and silicone resins containing crosslinkable functional groups by hydrosilylation reactions; adhesion improvers; heat-resistant additives such as metal oxides; antistatic agents; radiation shielding agents; electromagnetic shielding agents; preservatives; plasticizers; settling inhibitors; and solvents. When the composition of the present invention contains components other than the above components (a) to (i), the proportion of the other components other than the solvent in the solid content of the composition (meaning in the composition if the composition does not contain a solvent, and meaning in all components other than the solvent if the composition contains a solvent) is preferably 20% by mass or less, more preferably 15% by mass or less, even more preferably 10% by mass or less, also preferably 7% by mass or less, also preferably 5% by mass or less, and also preferably 3% by mass or less.

[0063] [Method for preparing a thermally conductive curable silicone composition] The method for preparing the composition of the present invention is not particularly limited as long as the composition contains the desired components. Typically, the composition of the present invention can be obtained by mixing the components to be included in the composition of the present invention. In preparing this composition, in order to prevent reactions from proceeding between two or more components having mutually reactive groups, it is preferable to keep the mixing temperature as low as possible and to perform the mixing process for a short time when mixing two or more components having mutually reactive groups in the presence of each other. Furthermore, the composition of the present invention can be stably stored without virtually causing a curing reaction by storing the prepared composition at a low temperature (for example, 10°C or lower, preferably 5°C or lower) or by adding a curing retarder.

[0064] As described above, in order to more efficiently create a state in which the thermally conductive filler surface of component (b) is treated with the alkyltrialkoxysilane compound of component (c), it is also preferable to prepare a mixture of components (b) and (c) in advance and incorporate this mixture in the preparation of the composition of the present invention. The same applies to the preparation of the two-component silicone composition set described below.

[0065] If the composition of the present invention is prepared immediately before use, unintended curing reactions before use can be more reliably suppressed. To facilitate the preparation of this composition immediately before use, it is preferable to prepare a two-component silicone composition set (hereinafter also referred to as the "two-component composition set of the present invention") for obtaining the composition of the present invention. Of the components of the composition of the present invention, component (e), the "hydrosilylation reaction catalyst," can be included in only one of the compositions constituting the two-component composition set, and component (g), the "organopolysiloxane compound having 1.5 or more hydrosilyl groups in the molecule and not having an alkenyl group," can be included in only the other composition constituting the two-component composition set. As a result, even if the remaining components other than components (e) and (g) are included in only one of the compositions constituting the two-component composition set, only the other composition, or each of both compositions, curing reactions are less likely to occur in the state of the two-component composition set. To more reliably suppress curing reactions, it is preferable to store the two-component composition set of the present invention at a low temperature. There are no particular restrictions on how components other than components (e) and (g) are distributed and included in the two compositions that constitute the two-component composition set of the present invention; it is sufficient to set it appropriately according to the composition of the composition of the present invention prepared by mixing the two liquids. That is, in one embodiment, the present invention provides the following two-component composition set.

[0066] A two-component composition set for obtaining the composition of the present invention, comprising a first liquid containing component (e) but not component (g), and a second liquid containing component (g) but not component (e). In this two-component composition set, all of the essential components constituting the composition of the present invention are contained in the first liquid and / or the second liquid.

[0067] In the two-component composition set of the present invention, a preferred example of the distribution of each component to the first liquid and the second liquid is that the first liquid contains at least components (a) to (e), and the second liquid contains at least components (a) to (c), (f), and (g).

[0068] According to one embodiment of the present invention, a method for producing the composition of the present invention is provided, comprising mixing the first liquid and the second liquid of the two-component composition set of the present invention. Preferably, in the preparation of the first liquid and / or the second liquid, the method for producing the composition of the present invention includes blending a mixture of component (b) and component (c). By blending component (b) and component (c) in this way, as described above, component (c) can efficiently interact with the surface of the thermally conductive filler of component (b) (for example, by causing a dehydration condensation reaction with the hydroxyl groups on the surface of the thermally conductive filler), thereby modifying the surface of the thermally conductive filler with higher efficiency.

[0069] The composition of the present invention, when subjected to a curing reaction, can be used to obtain a cured product with suitable physical properties for use as a gap filler in batteries for transport vehicles and the like. In other words, it is possible to provide a cured product (gap filler) that is resistant to peeling off and damage from the adherend even when repeatedly exposed to expansion, contraction, and vibration of the adherend, and that can sustainably exhibit highly efficient heat dissipation even when repeatedly driven while installed in a transport vehicle. The preferred characteristics of a cured product that achieves such physical properties will be described below, but the present invention is not limited to products having such characteristics other than those specified in the present invention.

[0070] [Preferred Properties of the Cured Product (Gap Filler)] <Thermal Conductivity> Thermal conductivity is an indicator of the thermal conductivity of the gap filler. For example, considering the efficient transfer of heat generated from the battery cell to the heat sink, the thermal conductivity of the gap filler is preferably 1.5 W / m·K or higher, and more preferably 2.0 W / m·K or higher. This thermal conductivity is usually 1.5 to 10.0 W / m·K, and may also be 2.0 to 5.0 W / m·K. The method for measuring thermal conductivity is described in the Examples section.

[0071] <Initial Maximum Shear Bonding Strength> The initial maximum shear bonding strength is an indicator of the initial bonding strength of the gap filler. For example, considering the expansion and contraction during the initial charging and discharging of automotive battery cells, and the adhesion to vibrations during driving, it is preferable that the initial maximum shear bonding strength of the gap filler be 0.6 MPa or higher, and more preferably 0.9 MPa or higher. There is no particular upper limit to the initial maximum shear bonding strength, and it is usually 2.0 MPa or lower. The method for measuring the initial maximum shear bonding strength is described in the Examples section.

[0072] <Initial Maximum Shear Bonding Strain> The initial maximum shear bonding strain is an indicator of the flexibility of the gap filler. Considering the expansion and contraction during the initial charging and discharging of automotive battery cells, as well as the adhesion to vibrations during driving, it is preferable that the initial maximum shear bonding strain of the gap filler be 90% or higher, and more preferably 140% or higher. There is no particular upper limit to the initial maximum shear bonding strain, and it is usually 250% or lower. The method for measuring the initial maximum shear bonding strain is described in the Examples section.

[0073] <Maximum Shear Bonding Strength After Durability Test> The maximum shear bonding strength after durability test is an indicator of the bonding strength after the gap filler has been subjected to continuous vibration and displacement. Considering that the adhesion must be maintained over the long term even against the expansion and contraction caused by repeated charging and discharging of automotive battery cells, as well as vibrations during driving, it is preferable that the maximum shear bonding strength of the gap filler after durability test be 0.5 MPa or higher, and more preferably 0.7 MPa or higher. There is no particular upper limit to the value of the maximum shear bonding strength after durability test, and it is usually 1.6 MPa or lower. The method for measuring the maximum shear bonding strength after durability test is described in the Examples section.

[0074] <Maximum Shear Bonding Strain After Durability Test> The maximum shear bonding strain after durability testing is an indicator of the flexibility of the gap filler after being subjected to continuous vibration and displacement. Considering that the adhesive properties must be maintained over the long term even against the expansion and contraction caused by repeated charging and discharging of automotive battery cells, as well as vibrations during driving, it is preferable that the maximum shear bonding strain of the gap filler after durability testing be 70% or higher, and more preferably 120% or higher. There is no particular upper limit to the value of the maximum shear bonding strain after durability testing, and it is usually 200% or less. The method for measuring the maximum shear bonding strain after durability testing is described in the Examples section.

[0075] The curing reaction conditions for the composition of the present invention are not particularly limited, as long as the reactive components in the composition of the present invention react sufficiently and the curing reaction proceeds. Therefore, there are no particular restrictions on the curing reaction temperature, for example, it can be 15 to 200°C, preferably 20 to 150°C, and more preferably 20 to 100°C. Similarly, there are no particular restrictions on the pressure during the curing reaction, for example, it can be atmospheric pressure (about 0.1 MPa) to 300 MPa, preferably atmospheric pressure to 100 MPa, and more preferably atmospheric pressure to 50 MPa. The reaction time can also be appropriately set according to the curing reaction conditions. For example, the composition of the present invention can be sufficiently cured in a curing reaction of about 10 minutes to 24 hours.

[0076] The present invention will be described in more detail based on examples and comparative examples, but the present invention is not limited to the following examples other than those specified herein.

[0077] [Example 1] <Preparation of a two-component silicone composition set>

[0078] -Preparation of the First Solution- The first solution, with the composition shown in the table below, was prepared as follows. A mixture M1 was obtained by uniformly mixing component (b) and component (c). The container of Hibismix 2P-1 (manufactured by Primix Corporation) was heated to 60°C, component (a) and component (h-1) were added, and then 2 / 5 of the total volume of mixture M1 was added. Mixing and stirring were performed at a rotation speed of 20 rpm under normal pressure for 3 minutes, then 1 / 3 of the remaining mixture M1 was added, and mixing and stirring were performed under the same conditions for another 5 minutes. After that, the temperature of the material (mixture) was raised to 100°C, and mixing and stirring were performed at a rotation speed of 20 rpm for 20 minutes while under vacuum. Subsequently, the entire remaining volume of mixture M1 was added, and mixing and stirring were performed under the same conditions for 15 minutes. After that, the temperature of the material was raised to 140°C, and mixing and stirring were performed at a rotation speed of 20 rpm under vacuum for 50 minutes. Next, the mixture was mixed and stirred for 45 minutes while cooling the material temperature to below 80°C. Finally, components (d) and (e) were added and mixed and stirred under vacuum at a rotation speed of 20 rpm for 30 minutes to obtain the "first liquid" in Example 1.

[0079] -Preparation of the second solution- The second solution, with the composition shown in the table below, was prepared as follows. A mixture M2 was obtained by uniformly mixing component (b) and component (c). The container of Hibismix 2P-1 (manufactured by Primix Corporation) was heated to 60°C, and component (a) and component (h-1) were added, followed by 2 / 5 of the total volume of mixture M2. The mixture was mixed and stirred at a rotation speed of 20 rpm under normal pressure for 3 minutes, then 1 / 3 of the remaining mixture M2 was added, and the mixture was mixed and stirred for another 5 minutes under the same conditions. After that, the material temperature was raised to 100°C, and the mixture was mixed and stirred at a rotation speed of 20 rpm for 20 minutes under vacuum. Subsequently, the entire remaining volume of mixture M2 was added, and the mixture was mixed and stirred for 15 minutes under the same conditions. After that, the material temperature was raised to 140°C, and the mixture was mixed and stirred at a rotation speed of 20 rpm under vacuum for 50 minutes. Next, the mixture was mixed and stirred for 45 minutes while cooling the material temperature to below 80°C. Finally, components (f), (g), and (i) were added and mixed and stirred under vacuum at a rotation speed of 20 rpm for 30 minutes to obtain the "second liquid" in Example 1.

[0080] <Preparation of Thermally Conductive Curable Silicone Composition> The first and second liquids were filled into a two-component mixing cartridge. A resin static mixer was attached to the tip of the cartridge, and the first and second liquids were mixed in a volume ratio of 1:1 using a cartridge gun to obtain the thermally conductive curable silicone composition of Example 1. In this composition, the ratio (Gm / Am) of the total molar amount of hydrosilyl groups in component (g) to the total molar amount of alkenyl groups in component (a) (Am) was 1.0. This ratio was the same in other examples and comparative examples.

[0081] <Preparation of Cured Product-1 (Test Piece-1)> Using the cartridge gun and static mixer described above, the first liquid and the second liquid were mixed in a volume ratio of 1:1 to produce a thermally conductive curable silicone composition, which was then extruded into a mold measuring 150 mm (length) x 150 mm (width) x 10 mm (thickness). Using a mini test press MP-SCL (manufactured by Toyo Seiki Co., Ltd.), the mixture was pressurized at a pressure of 30 MPa and cured at room temperature (approximately 25°C) for 24 hours to produce Cured Product-1 (Test Piece-1) in Example 1. This Test Piece-1 was used to measure thermal conductivity and specific gravity.

[0082] <Preparation of Cured Product-2 (Test Piece-2)> Using the cartridge gun and static mixer described above, the first liquid and the second liquid were mixed in a volume ratio of 1:1 to produce a thermally conductive curable silicone composition, which was then extruded onto an aluminum (A5052) plate 1 measuring 60 mm in length, 25 mm in width, and 2 mm in thickness. A separately prepared aluminum (A5052) plate 2 measuring 60 mm in length, 25 mm in width, and 2 mm in thickness was pressed against the extruded surface. The two plates were positioned so that the distance between them was 2 mm and the bonding area between them was 25 mm in the length direction and 25 mm in the width direction, with the long axes of both plates aligned and an overlap of 25 mm being created. In this state, the cured product-2 (test piece-2) from Example 1 was produced by curing at room temperature (approximately 25°C) for 24 hours. In this test specimen-2, a 2 mm thick layer of cured material (gap filler) was present across the entire bonding area (25 mm x 25 mm) between aluminum plates 1 and 2, and the aluminum plates 1 and 2 were bonded together by this cured material. This test specimen-2 was used to measure shear bonding strength and shear bonding strain.

[0083] [Examples 2-30, Comparative Examples 1-11] Except that the compositions of the first and second liquids were as shown in the table below, two-component silicone composition sets, thermally conductive curable silicone compositions, cured product-1 (test piece-1), and cured product-2 (test piece-2) were obtained for each of Examples 2-30 and Comparative Examples 1-11 in the same manner as in Example 1.

[0084] [Test Example] <Measurement of Thermal Conductivity> Test specimen-1 was used to measure the thermal conductivity. Specifically, the thermal conductivity was measured using the hot-wire method with a rapid thermal conductivity meter QTM-500 (manufactured by Kyoto Electronics Manufacturing Co., Ltd.). <Evaluation Criteria for Thermal Conductivity> ◎: 1.5 W / m·K or higher ×: Less than 1.5 W / m·K

[0085] <Measurement of Initial Maximum Shear Bonding Strength and Maximum Shear Bonding Strain> Test specimen-2 was attached to an Autograph AGX-V (10 kN) and pulled in the longitudinal direction at a speed of 50 mm / min in an environment of 23°C (i.e., aluminum plates 1 and 2 were moved relative to each other in opposite directions in the longitudinal direction) to separate aluminum plates 1 and 2. At this time, the maximum load of the load-strain curve obtained and the displacement value corresponding to that point (relative distance of movement in the longitudinal direction) were used to determine the initial maximum shear bonding strength and initial maximum shear bonding strain from the following formula. For the principle of the method for measuring maximum shear bonding strength and maximum shear bonding strain, refer to the description in

[0081] and Figure 7 of Japanese Patent Publication No. 2024-022613. Also, in the following formula, "thickness of the cured material (mm)" is the thickness of test specimen-2 before pulling in the longitudinal direction, i.e., 2 mm. {Initial Maximum Shear Bonding Strength (MPa)} = {Maximum Load (N)} / {Bonding Area (mm)} ２ {Initial maximum shear bonding strain (%) = 100 × {Displacement of the point corresponding to the maximum load (mm)} / {Thickness of the cured material (mm)} <Criteria for evaluating initial maximum shear bonding strength> ◎: 0.9 MPa or more ○: 0.6 MPa or more and less than 0.9 MPa ×: Less than 0.6 MPa <Criteria for evaluating initial maximum shear bonding strain> ◎: 140% or more ○: 90% or more and less than 140% ×: Less than 90%

[0086] <Measurement of Maximum Shear Bond Strength and Maximum Shear Bond Strain After Durability Test> Test specimen-2 was attached to an Autograph AGX-V (10kN) and subjected to 2000 shear vibrations at 1Hz within a strain range of 0 to 1.2mm. Subsequently, the maximum shear bond strength and maximum shear bond strain after the durability test were determined in the same manner as above. <Evaluation Criteria for Maximum Shear Bond Strength After Durability Test> ◎: 0.7MPa or higher ○: 0.5MPa or higher and less than 0.7MPa ×: Less than 0.5MPa <Evaluation Criteria for Maximum Shear Bond Strain After Durability Test> ◎: 120% or higher ○: 70% or higher and less than 120% ×: Less than 70%

[0087] <Measurement of Specific Gravity> A 10mm x 10mm x 10mm block was cut from test piece-1, and the density of pure water was measured at 23°C using an automatic hydrometer (D-1: manufactured by Toyo Seiki Co., Ltd.) at a temperature of 0.998 g / cm³. ３ The specific gravity of test specimen-1 was measured.

[0088] The component composition of the composition set or composition and the results of the above tests for each of the above examples and comparative examples are shown below. In the table below, "octyl" means a straight chain. Also, "AEROSIL R972" is fumed silica that has been surface hydrophobized with dimethyldichlorosilane. Furthermore, the chemical structures of compounds 1 to 5 are as follows.

[0089]

[0090]

[0091]

[0092]

[0093]

[0094]

[0095]

[0096] Examples 1 to 3 and Comparative Examples 1 and 2 are experimental examples in which the amount of the alkyltrialkoxysilane compound of component (c) was varied. In Examples 1 to 3 (0.5 parts by mass, 0.1 parts by mass, and 1.5 parts by mass, respectively), where the amount of component (c) was blended in the range of 0.1 to 1.5 parts by mass per 100 parts by mass of the thermally conductive filler of component (b), the resulting cured products all exhibited excellent thermal conductivity and excellent adhesive strength and adhesive strain (flexibility) both initially and after durability testing. On the other hand, in Comparative Example 1, in which component (c) was not blended, the fluidity of the first or second liquid was poor to begin with, and it was not possible to prepare test specimens. Furthermore, in Comparative Example 2 (1.6 parts by mass), where the amount of component (c) was blended in the range of 1.5 parts by mass per 100 parts by mass of component (b), the resulting cured product was inferior in both adhesive strength and flexibility both initially and after durability testing. When the cured product of Comparative Example 2 was used, for example, as a gap filler for battery cells or battery modules mounted on a transport aircraft, this gap filler could not adequately follow the continuous expansion and contraction of the battery cells or battery modules or the continuous vibrations during operation, and thus could not maintain its adhesive properties. Comparative Example 3 did not contain the condensation reaction catalyst of component (d) in its composition. The cured product of Comparative Example 3 obtained from this composition showed clear damage after durability testing and was inferior in practical use as a gap filler, etc.

[0097]

[0098]

[0099] Comparative Example 4 is an experimental example in which the organosilicon compound of component (f) is not included. Examples 4 to 7 and Comparative Example 5 are experimental examples in which compound 1 is used as component (f) and its amount is varied.

[0100] The cured product of Comparative Example 4, which did not contain component (f), was inferior in both initial adhesive strength and flexibility, and clearly showed damage after the durability test, making it unsuitable for practical use as a gap filler, etc. The cured product of Comparative Example 5, in which the content of component (f) was higher than that specified in the present invention, also lacked sufficient initial flexibility, and clearly showed damage after the durability test, making it unsuitable for practical use as a gap filler, etc. In contrast, the cured products of Examples 4 to 7, which contained component (f) in the specific amount specified in the present invention, had sufficient adhesion and flexibility both initially and after the durability test.

[0101]

[0102]

[0103] Examples 8 and 9 are experimental examples using compound 2 and compound 3 as component (f), respectively. Comparative Examples 10 and 11 have the same ring structure as the chemical structure of component (f), but with an alkylene group (-(CH ２ ) ｎ This is an experimental example in which compounds 4 and 5, whose chain lengths are outside the specified range for component (f), were used in place of component (f). From the results shown in the table above, it can be seen that the chain length of the alkylene group in the chemical structure of component (f) is an important technical element in the manifestation of the desired effect.

[0104]

[0105]

[0106] Comparative Examples 6 to 9 are experimental examples in which tetraethoxysilane was used instead of component (f). Tetraethoxysilane corresponds to component (C-1) used in the composition described in Japanese Patent Publication No. 7368656. When tetraethoxysilane was used, regardless of the amount added, the cured product showed inferior initial adhesive strength and flexibility. Furthermore, after the durability test, the test pieces peeled off or broke, failing to meet the gap filler properties required by the present invention. In addition, cured products (test pieces-1 and test pieces-2) were prepared in the same manner as above from a two-component composition (first liquid and second liquid) consisting of the composition of Example 1 of Japanese Patent Publication No. 7368656, and evaluated in the same manner as above. As a result, both initial adhesive strength and flexibility were inferior (both received a × rating), and furthermore, after the durability test, the test pieces peeled off or broke, failing to meet the gap filler properties required by the present invention. It was also found that the specific gravity of the cured product was high.

[0107]

[0108]

[0109] Examples 10-12 are experimental examples in which the amount of the optional component (h-1) was varied. Examples 10, 13-15 are examples in which the amount of the optional component (h-2) was varied. It was found that the cured product exhibited excellent properties as a gap filler whether or not component (h-1) or (h-2) was included. Although not shown in the table, it was also confirmed that the adhesive strength tended to be further increased by including a predetermined amount of component (h-1) or (h-2) (adhesive strength improved in the order of Examples 10, 11, and 12, and similarly in the order of Examples 10, 13, 14, and 15).

[0110]

[0111]

[0112] Examples 16 to 18 are experimental cases in which the amount of component (i), an optional component, was varied. It was found that the cured product exhibited excellent gap filler properties whether or not component (i) was included. Furthermore, it was shown that the adhesive strength tended to be further increased by including a predetermined amount of component (i).

[0113]

[0114]

[0115] Examples 19 to 22 are experimental examples in which the type of component corresponding to the optional component (i) is changed. In Example 19, vinyltrimethoxysilane was used; in Example 20, 4-pentenyltrimethoxysilane; in Example 21, 11-dodecenyltrimethoxysilane; and in Example 22, 17-octadecenyltrimethoxysilane. It was found that the alkenyltrialkoxysilane of component (i) contributes to higher adhesive strength and flexibility because the number of carbon atoms in the alkenyl group is within the range of 3 to 16. Conversely, it was also found that when alkenyltrialkoxysilanes with an alkenyl group outside the range of 3 to 16 carbon atoms were incorporated, the adhesive strength and flexibility tended to decrease compared to when they were not incorporated (comparison between Example 18 and Examples 19 and 22).

[0116]

[0117]

[0118] Examples 23 to 26 are examples in which the amount of thermally conductive filler (aluminum hydroxide) in component (b) was varied. It was found that the cured product exhibited excellent properties as a gap filler regardless of the amount of component (b) included. It was also found that by setting the amount of component (b) in the composition to 67 to 73 volume%, a higher level of balance between adhesive strength and flexibility in the cured product could be achieved.

[0119]

[0120]

[0121] Examples 27-29 are experimental examples in which the amount of component (b) (aluminum oxide) is varied. Example 30 is an example in which aluminum hydroxide and aluminum oxide are used in combination as component (b). It can be seen that the specific gravity of the cured product can be reduced by using aluminum hydroxide as component (b).

[0122] As described above, by using the composition of the present invention, the cured product obtained by curing this composition can be made to have excellent adhesive strength and flexibility, and it has also been shown that these properties can be stably maintained even when exposed to repeated vibration stress. Therefore, the composition of the present invention can be suitably used, for example, to form gap fillers used in batteries mounted on transport aircraft.

Claims

1. A thermally conductive curable silicone composition comprising the following components (a) to (g): (a) a linear organopolysiloxane compound having 1.5 to 2.0 alkenyl groups at the molecular chain ends and lacking hydrosilyl groups; (b) a thermally conductive filler; (c) an alkyltrialkoxysilane compound; (d) a condensation reaction catalyst; (e) a hydrosilylation reaction catalyst; (f) an organosilicon compound represented by the following general formula (1); In the formula, R １ and R ２ Each of these independently represents an alkyl group having 1 to 4 carbon atoms. ３ Each independently represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms. Each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. m is an integer from 0 to 8, and n is an integer from 3 to 8. (g) An organopolysiloxane compound having 1.5 or more hydrosilyl groups in the molecule and no alkenyl groups; The content of component (f) is 0.5 to 10 parts by mass per 100 parts by mass of component (a), the content of component (b) is 60 to 82 volume% in the thermally conductive curable silicone composition, the content of component (c) is 0.1 to 1.5 parts by mass per 100 parts by mass of component (b), and the ratio of the total molar amount of hydrosilyl groups in component (g) (Gm / Am) to the total molar amount of alkenyl groups in component (a) (Am) is 0.5 to 5.0, a thermally conductive curable silicone composition.

2. The thermally conductive curable silicone composition according to claim 1, wherein the thermally conductive curable silicone composition contains at least one of the following components (h-1) and (h-2): (h-1) a silicone resin having an alkenyl group; (h-2) hydrophobic silica; and the total content of each of the components (h-1) and (h-2) is 0.1 to 5 parts by mass per 100 parts by mass of the content of component (a).

3. The thermally conductive curable silicone composition according to claim 2, wherein the thermally conductive curable silicone composition contains the following component (i): (i) an alkenyltrialkoxysilane having 3 to 16 carbon atoms in the alkenyl group; the content of component (i) is 0.1 to 3 parts by mass per 100 parts by mass of component (a).

4. The thermally conductive curable silicone composition according to claim 3, wherein component (b) comprises at least one of aluminum hydroxide and aluminum oxide, and the content of component (b) in the thermally conductive curable silicone composition is 67 to 73% by volume.

5. The thermally conductive curable silicone composition according to claim 4, wherein the proportion of aluminum hydroxide in component (b) is 70% by volume or more.

6. A cured product obtained by curing the thermally conductive curable silicone composition according to any one of claims 1 to 5.

7. A gap filler comprising the cured product described in claim 6.

8. The gap filler according to claim 7, for application to batteries mounted on transport aircraft.

9. A two-component silicone composition set for obtaining the thermally conductive curable silicone composition according to any one of claims 1 to 5, comprising a first liquid containing component (e) but not containing component (g), and a second liquid containing component (g) but not containing component (e).

10. The two-component silicone composition set according to claim 9, wherein the first liquid comprises at least components (a) to (e), and the second liquid comprises at least components (a) to (c), (f), and (g).

11. A method for producing a thermally conductive curable silicone composition according to any one of claims 1 to 5, comprising mixing the first liquid and the second liquid of the two-component silicone composition set according to claim 9.

12. A method for producing a thermally conductive curable silicone composition according to claim 11, comprising incorporating a mixture of component (b) and component (c) in the preparation of the first liquid and / or the second liquid.

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