Heat-softenable thermally conductive silicone composition and heat-softenable thermally conductive cured silicone product

Abstract

The present invention is a heat-softenable thermally conductive silicone composition characterized by comprising components (A) to (E): (A) a phenyl-modified organopolysiloxane; (B) an organohydrogenpolysiloxane; (C) one or more selected from the group consisting of organopolysiloxanes having a hydrolyzable functional group and alkoxysilane compounds represented by general formula (2); (D) one or more selected from the group consisting of metallic gallium and gallium alloys having a melting point of 0 to 70°C; and (E) a platinum group metal catalyst. The present invention makes it possible to achieve excellent heat-softenability, reworkability and compressibility, and to realize low thermal resistance.

Description

Thermosoftening thermally conductive silicone composition and thermosoftening thermally conductive silicone cured product

[0001] This invention relates to a thermosoftening, thermally conductive silicone composition and a thermosoftening, thermally conductive silicone cured product.

[0002] Electronic components such as CPUs, which are highly integrated circuits, experience a significant decrease in performance due to the heat generated during use. To solve this problem, heat dissipation materials are used to improve heat transfer efficiency by being introduced into the air layer between the heat-generating and cooling parts. Among these, silicone heat dissipation materials are widely used in various fields due to their high heat resistance, weather resistance, and electrical insulation properties derived from silicone. Furthermore, in recent years, as electronic devices have become smaller and more highly integrated, it has become important to cool the generated heat more efficiently, thus requiring heat dissipation materials with higher thermal conductivity.

[0003] In recent years, phase-change heat dissipation materials (phase-change materials) that are solid at room temperature and soften when heated have been proposed. Phase-change materials are mounted between electronic components and heat sinks, and when heated, the softened phase-change material conforms to the warping and unevenness of the electronic components and heat sink, significantly reducing the interfacial contact thermal resistance and improving heat dissipation characteristics.

[0004] It is known that in general phase-change materials, α-olefin resins or paraffin waxes are used as resin components, and these are compounded with thermally conductive fillers to exhibit phase-change functionality (Patent Document 1). However, these organic compound-based phase-change materials have problems such as poor heat resistance and flame retardancy.

[0005] On the other hand, silicone is known as a material with excellent heat resistance and flame retardancy, and many phase-change materials using silicone as a resin component have been reported. In fact, it is known that heat dissipation members consisting of thermoplastic silicone resin and a thermally conductive filler have improved heat resistance and flame retardancy (Patent Document 2). Thermoplastic silicone resin having a T unit is mainly used as the resin component of the above-mentioned silicone-based phase-change material. However, because thermoplastic silicone resin is highly tacky, conventional silicone resin-based phase-change materials have the problem of poor reworkability. In recent years, there has been a demand for heat dissipation materials that can be easily attached and detached from the viewpoint of workability and handling.

[0006] Furthermore, while heat dissipation materials, including phase-change materials, are obtained by incorporating thermally conductive fillers to impart thermal conductivity, a large amount of thermally conductive filler impairs compressibility. This limits the upper limit of the amount of thermally conductive filler that can be incorporated, resulting in the drawback of not being able to obtain sufficient thermal conductivity.

[0007] To enhance the heat conduction effect, methods have been proposed such as incorporating low-melting-point metals into a heat-conductive paste (Patent Documents 3 and 4), and using granular materials that fix and stabilize liquid metals within a three-phase composite (Patent Document 5). However, these heat-conductive materials using low-melting-point metals have problems such as contaminating parts other than the coated area, and leaking oily substances after prolonged use.

[0008] Japanese Patent Publication No. 2000-509209, International Publication No. 2002 / 091465, Japanese Patent Publication No. Hei 7-207160, Japanese Patent Publication No. Hei 8-53664, Japanese Patent Publication No. 2002-121292, Japanese Patent Publication No. 2005-112961, Japanese Patent Publication No. 2024-142155

[0009] The present invention has been made to solve the above problems, and aims to provide a thermosoftening, thermally conductive silicone composition that is excellent in thermosoftening, reworkability, and compressibility and can achieve low thermal resistance, as well as a thermosoftening, thermally conductive silicone cured product that is excellent in thermosoftening, reworkability, and compressibility and can achieve low thermal resistance.

[0010] In order to solve the above problems, the present invention provides a thermoplastic thermally conductive silicone composition, which is characterized by containing the following components (A) to (E). (A) A phenyl-modified organopolysiloxane having two or more alkenyl groups in one molecule and having a kinematic viscosity at 25°C of 100 to 100,000 mm ２ / s: 100 parts by mass, (B) An organohydrogenpolysiloxane having at least two hydrosilyl groups at the molecular chain ends, in an amount such that the molar number of hydrosilyl groups in component (B) is 0.1 to 3 moles with respect to 1 mole of the alkenyl groups in component (A), (C) One or more selected from the group consisting of an organopolysiloxane having a hydrolyzable functional group and an alkoxysilane compound represented by the following general formula (2): 10 to 1,000 parts by mass, R ３ ｂ R ４ ｃ Si(OR ５ ) ４－ｂ－ｃ (2) (In the formula, R ３ is independently an alkyl group having 6 to 15 carbon atoms, R ４ is independently a monovalent hydrocarbon group having 1 to 15 carbon atoms, R ５ is independently an alkyl group having 1 to 6 carbon atoms, b is an integer of 1 to 3, c is an integer of 0 to 2, provided that b + c is an integer of 1 to 3.) (D) One or more selected from the group consisting of metallic gallium and gallium alloys having a melting point of 0 to 70°C: 300 to 5,000 parts by mass, (E) A platinum group metal catalyst: 0.01 to 1,000 ppm on a mass basis converted to platinum group metal atoms with respect to the mass of component (A).

[0011] Such a thermoplastic thermally conductive silicone composition can be a thermoplastic thermally conductive silicone composition excellent in both thermoplasticity and reworkability.

[0012] Furthermore, the cured product of such a thermosoftening, thermally conductive silicone composition contains a necessary and sufficient amount, specifically 300 to 5,000 parts by mass, of one or more components (D) selected from the group consisting of metallic gallium and gallium alloys, which have a melting point of 0 to 70°C, and functions as a thermally conductive filler. At high temperatures, component (D) liquefies and improves compressibility, enabling thin-film formation under low-pressure conditions, and as a result, enabling low thermal resistance.

[0013] Furthermore, because the cured product of the thermosoftening, thermally conductive silicone composition of the present invention is thermosoftening, when, for example, a heat dissipation member is heated and pressed into place, it can follow the surface irregularities of both the heat dissipation member and the heat-generating electronic component, allowing them to adhere tightly without creating any gaps between them, thereby minimizing interfacial thermal resistance.

[0014] Furthermore, when the heat dissipation member is heated and pressed together, the (D) component contained in the thermosoftening thermal conductive silicone composition of the present invention, which has a melting point of 0 to 70°C, can become, for example, liquid fine particles. These liquid fine particles aggregate to form larger liquid particles, and these larger liquid particles can connect to each other and form a kind of pathway. Such liquid particles can be uniformly dispersed in a thermosoftening matrix consisting of resin components derived from components (A) to (C) and (E) of the thermosoftening thermal conductive silicone composition of the present invention, forming a uniform heat conduction pathway throughout the matrix. Therefore, by interposing a cured product of the thermosoftening thermal conductive silicone composition of the present invention between a heat-generating electronic component and a heat dissipation member, heat generated from the heat-generating electronic component can be quickly conducted to the heat dissipation member, and a higher heat dissipation effect can be reliably achieved than with conventional phase-change materials.

[0015] Furthermore, in the cured product obtained by curing the thermosoftening thermal conductive silicone composition of the present invention, the metallic gallium and / or its alloy forming the heat conduction pathway can be fixed and held within a three-dimensional crosslinked network of resins derived from components (A) to (C) and (E) of the thermosoftening thermal conductive silicone composition of the present invention. As a result, the cured product of the thermosoftening thermal conductive silicone composition of the present invention does not contaminate other components, which was a problem with conventional heat dissipation materials, nor does it leak oily substances over time. Therefore, the reliability of devices including heat-generating electronic components, such as semiconductor devices, can be further improved.

[0016] In other words, the thermosoftening, thermally conductive silicone composition of the present invention exhibits excellent thermosoftening properties, excellent reworkability, and excellent compressibility, thereby achieving low thermal resistance. Furthermore, by curing the thermosoftening, thermally conductive silicone composition of the present invention, a cured product can be obtained that exhibits excellent thermosoftening properties, excellent reworkability, and excellent compressibility, thereby achieving low thermal resistance.

[0017] Furthermore, in the present invention, it is preferable that the organopolysiloxane having a hydrolyzable functional group of component (C) is represented by the following general formula (1). (In the formula, R １ R is independently an aromatic hydrocarbon group having 6 to 10 carbon atoms, or independently an alkyl group having 1 to 10 carbon atoms. ２ (where a is an alkyl group having 1 to 4 carbon atoms; a is 2 or 3, and n is an integer between 2 and 60; provided that it contains 1% or more of an aromatic hydrocarbon group having 6 to 10 carbon atoms.)

[0018] The organopolysiloxane having a hydrolyzable functional group of component (C) is not particularly limited, but such a structure is preferred.

[0019] Furthermore, in the present invention, it is preferable that the heat-softening, heat-conductive silicone composition further contains a non-reactive phenyl-modified organopolysiloxane as component (F).

[0020] The thermosoftening, thermally conductive silicone composition of the present invention may contain such (F) component.

[0021] In this case, it is preferable that the thermosoftening, thermally conductive silicone composition of the present invention contains 1 to 500 parts by mass of component (F) per 100 parts by mass of component (A).

[0022] With this amount of component (F), the viscosity of the composition and its cured product can be reduced without reducing processability.

[0023] Furthermore, the present invention provides a heat-softening, heat-conducting silicone cured product, which is a heat-softening, heat-conducting silicone composition described above that has been cured.

[0024] Such a thermosoft, thermally conductive silicone cured product can exhibit excellent thermosoftening properties, excellent reworkability, and excellent thermal conductivity. Furthermore, the thermosoft, thermally conductive silicone cured product of the present invention has excellent compressibility, and thinning and low thermal resistance are possible even under low pressure conditions.

[0025] More specifically, because the heat-softening, thermally conductive silicone cured product of the present invention is heat-softening, when, for example, a heat dissipation member is heated and pressed into place, it can conform to the surface irregularities of both the heat dissipation member and the heat-generating electronic component, allowing them to adhere tightly without creating any gaps between them, thereby minimizing interfacial thermal resistance.

[0026] Furthermore, when the heat dissipation member is heated and pressed together, the (D) component contained in the heat-softening, heat-conductive silicone cured product of the present invention, which has a melting point of 0 to 70°C, can become, for example, liquid fine particles. These liquid fine particles aggregate to form larger liquid particles, and these larger liquid particles can connect to each other and form a kind of pathway. Such liquid particles can be uniformly dispersed in a heat-softening matrix consisting of resin components derived from components (A) to (C) and (E) of the heat-softening, heat-conductive silicone composition of the present invention, forming a uniform heat conduction pathway throughout the matrix. Therefore, by interposing the heat-softening, heat-conductive silicone cured product of the present invention between a heat-generating electronic component and a heat dissipation component, heat generated from the heat-generating electronic component can be quickly conducted to the heat dissipation component, and a higher heat dissipation effect can be reliably achieved than with conventional phase-change materials.

[0027] Furthermore, in the thermosoftening, thermally conductive silicone cured product of the present invention, the metallic gallium and / or its alloy forming the heat conduction pathway can be fixed and held within a three-dimensional crosslinked network of resins derived from components (A) to (C) and (E) of the thermosoftening, thermally conductive silicone composition of the present invention. As a result, the thermosoftening, thermally conductive silicone cured product of the present invention does not contaminate other components, which was a problem with conventional heat dissipation materials, nor does it leak oily substances over time. Therefore, the reliability of devices including heat-generating electronic components, such as semiconductor devices, can be further improved.

[0028] In other words, the heat-softening, heat-conductive silicone cured product of the present invention can exhibit excellent heat softening properties, excellent reworkability, and excellent compressibility, and can achieve low thermal resistance.

[0029] As described above, the thermosoftening, thermally conductive silicone composition of the present invention exhibits excellent thermosoftening properties, excellent reworkability, and excellent compressibility, thereby achieving low thermal resistance.

[0030] Furthermore, the heat-softening, heat-conductive silicone cured product of the present invention exhibits excellent heat softening properties, excellent reworkability, and excellent compressibility, thereby achieving low thermal resistance.

[0031] As described above, there has been a need for the development of a thermosoftening, thermally conductive silicone composition that is excellent in thermosoftening, reworkability, and compressibility, and that can achieve low thermal resistance, as well as a thermosoftening, thermally conductive silicone cured product that is excellent in thermosoftening, reworkability, and compressibility, and that can achieve low thermal resistance.

[0032] As a result of diligent research into the above problems, the inventors of the present invention have found that a thermo-softening, thermally conductive silicone composition containing the following components (A) to (E) can solve the above problems, and have completed the present invention.

[0033] In other words, the present invention is a thermosoftening, thermally conductive silicone composition characterized by containing the following components (A) to (E): (A) Having two or more alkenyl groups in one molecule and having a kinematic viscosity of 100 to 100,000 mm at 25°C ２ / s phenyl-modified organopolysiloxane: 100 parts by mass, (B) organohydrogenpolysiloxane having at least two hydrosilyl groups at the molecular chain ends: in an amount such that the number of moles of hydrosilyl groups in component (B) is 0.1 to 3 moles per mole of alkenyl groups in component (A), (C) one or more selected from the group consisting of organopolysiloxanes having hydrolyzable functional groups and alkoxysilane compounds represented by the following general formula (2): 10 to 1,000 parts by mass, R ３ ｂ R ４ ｃ Si ( OR ５ ) ４－ｂ－ｃ (2) (wherein, R ３ R is an alkyl group having 6 to 15 carbon atoms, ４ R is an independent monovalent hydrocarbon group having 1 to 15 carbon atoms. ５ (A) is an alkyl group having 1 to 6 carbon atoms independently, b is an integer from 1 to 3, and c is an integer from 0 to 2, provided that b + c is an integer from 1 to 3. (D) One or more selected from the group consisting of metallic gallium and gallium alloys having a melting point of 0 to 70°C: 300 to 5,000 parts by mass, (E) Platinum group metal catalyst: 0.01 to 1,000 ppm on a mass basis converted to platinum group metal atoms relative to the mass of component (A).

[0034] Such a thermosoftening, thermally conductive silicone composition of the present invention can be obtained that exhibits excellent thermosoftening properties as well as excellent reworkability.

[0035] Furthermore, the cured product of such a thermosoftening, thermally conductive silicone composition contains a necessary and sufficient amount, specifically 300 to 5,000 parts by mass, of one or more components (D) selected from the group consisting of metallic gallium and gallium alloys, which have a melting point of 0 to 70°C, and functions as a thermally conductive filler. At high temperatures, component (D) liquefies and improves compressibility, enabling thin-film formation under low-pressure conditions, and as a result, enabling low thermal resistance.

[0036] Furthermore, because the cured product of the thermosoftening, thermally conductive silicone composition of the present invention is thermosoftening, when, for example, a heat dissipation member is heated and pressed into place, it can follow the surface irregularities of both the heat dissipation member and the heat-generating electronic component, allowing them to adhere tightly without creating any gaps between them, thereby minimizing interfacial thermal resistance.

[0037] Furthermore, when the heat dissipation member is heated and pressed together, the (D) component contained in the thermosoftening thermal conductive silicone composition of the present invention, which has a melting point of 0 to 70°C, can become, for example, liquid fine particles. These liquid fine particles aggregate to form larger liquid particles, and these larger liquid particles can connect to each other and form a kind of pathway. Such liquid particles can be uniformly dispersed in a thermosoftening matrix consisting of resin components derived from components (A) to (C) and (E) of the thermosoftening thermal conductive silicone composition of the present invention, forming a uniform heat conduction pathway throughout the matrix. Therefore, by interposing a cured product of the thermosoftening thermal conductive silicone composition of the present invention between a heat-generating electronic component and a heat dissipation member, heat generated from the heat-generating electronic component can be quickly conducted to the heat dissipation member, and a higher heat dissipation effect can be reliably achieved than with conventional phase-change materials.

[0038] Furthermore, in the cured product obtained by curing the thermosoftening thermal conductive silicone composition of the present invention, the metallic gallium and / or its alloy forming the heat conduction pathway can be fixed and held within a three-dimensional crosslinked network of resins derived from components (A) to (C) and (E) of the thermosoftening thermal conductive silicone composition of the present invention. As a result, the cured product of the thermosoftening thermal conductive silicone composition of the present invention does not contaminate other components, which was a problem with conventional heat dissipation materials, nor does it leak oily substances over time. Therefore, the reliability of devices including heat-generating electronic components, such as semiconductor devices, can be further improved.

[0039] In other words, the thermosoftening, thermally conductive silicone composition of the present invention exhibits excellent thermosoftening properties, excellent reworkability, and excellent compressibility, thereby achieving low thermal resistance. Furthermore, by curing the thermosoftening, thermally conductive silicone composition of the present invention, a cured product can be obtained that exhibits excellent thermosoftening properties, excellent reworkability, and excellent compressibility, thereby achieving low thermal resistance.

[0040] Patent Document 6 discloses a curable organopolysiloxane containing gallium and / or its alloys, having a melting point of 0 to 70°C. However, Patent Document 6 does not describe or suggest that all of the components (A) to (C) included in the thermosoftening, thermally conductive silicone composition of the present invention are included. Therefore, the composition described in Patent Document 6 cannot achieve the fixation and retention of gallium and / or its alloys by a three-dimensional crosslinked network of resins derived from the above components (A) to (C) and (E), as in the present invention.

[0041] Furthermore, Patent Document 7 discloses an organopolysiloxane having a hydrolyzable group that corresponds to the organopolysiloxane used as component (C) in the present invention, a wetter made of this organopolysiloxane, and a composition which is a colorless, transparent liquid containing phenyl-modified silicone and this organopolysiloxane. However, Patent Document 7 does not relate to a curing composition.

[0042] The present invention will be described in detail below, but the present invention is not limited to these descriptions.

[0043] [Thermo-softening, thermally conductive silicone composition] The present invention is a thermo-softening, thermally conductive silicone composition comprising the above components (A) to (E). Furthermore, the thermo-softening, thermally conductive silicone composition of the present invention may optionally contain the following component (F) or other components. Each component will be described in detail below.

[0044] [(A) Phenyl-modified organopolysiloxane] Component (A) has two or more alkenyl groups in the molecule, preferably 2 to 10, more preferably 2 to 5, and has a kinematic viscosity of 100 to 100,000 mm at 25°C. ２ It is a phenyl-modified organopolysiloxane with R' / s. Component (A) is R' １ SiO ３／２ It is preferable that it does not contain units (T units) (R' in the formula). １ (This is a substituted or unsubstituted monovalent hydrocarbon group.)

[0045] The main chain of the phenyl-modified organopolysiloxane of component (A) is preferably composed of diorganosiloxane units, and more preferably is a linear organopolysiloxane.

[0046] The alkenyl group is preferably an alkenyl group having 2 to 8 carbon atoms, more preferably 2 to 6 carbon atoms. Examples include vinyl, allyl, propenyl, isopropenyl, butenyl, hexenyl, cyclohexenyl, and octenyl groups. The vinyl group is particularly preferred. The alkenyl group may be bonded to a silicon atom at the end of the molecular chain, a silicon atom in the middle of the molecular chain, or both.

[0047] Furthermore, the phenyl-modified organopolysiloxane of component (A) preferably has 0.0000001 to 0.005 mol / g, particularly 0.00001 to 0.005 mol / g of alkenyl groups per molecule.

[0048] Furthermore, the phenyl-modified organopolysiloxane of component (A) has phenyl groups. The amount of phenyl groups in one molecule is preferably 5 to 100%, and more preferably 20 to 100%, of the siloxane units containing phenyl groups per total siloxane unit. If the amount of phenyl groups in one molecule is within the above range relative to the total siloxane units, the thermal softening properties of the thermosoftening thermal conductive silicone composition and the cured product will be good.

[0049] Furthermore, the phenyl-modified organopolysiloxane of component (A) may contain phenyl groups at either the terminal or side chain, but it is preferable that the phenyl groups be contained only in the side chain.

[0050] Furthermore, the phenyl-modified organopolysiloxane of component (A) may have groups other than the alkenyl group and the phenyl group. From the viewpoint of viscosity, groups other than the alkenyl group and the phenyl group are preferably alkyl groups having 1 to 18 carbon atoms, preferably 1 to 10 carbon atoms, and more preferably 1 to 8 carbon atoms. Examples include methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, pentyl group, neopentyl group, hexyl group, cyclohexyl group, octyl group, nonyl group, decyl group, etc. It is also possible to use alkyl groups in which some of the hydrogen atoms are substituted with halogen atoms. Among the alkyl groups, the methyl group is particularly preferred.

[0051] Furthermore, the phenyl-modified organopolysiloxane of component (A) has a kinematic viscosity of 100 to 100,000 mm² at 25°C. ２ The kinematic viscosity is / s. In this invention, the kinematic viscosity is the value measured by an Ostwald viscometer as described in JIS Z8803:2011. The kinematic viscosity is preferably 300 to 20,000 mm². ２ / s, and more preferably 500 to 10,000 mm ２ It is / s. The kinematic viscosity is 100 mm ２ If the value is less than / s, the phenyl modification rate becomes too small, which is undesirable. Also, if the kinematic viscosity is 100,000 mmHg ２ If the value exceeds / s, it becomes difficult to handle the thermo-softening, thermally conductive silicone composition, which is undesirable.

[0052] In the thermosoftening, thermally conductive silicone composition of the present invention, one type of phenyl-modified organopolysiloxane may be used alone, or two or more types may be used in combination.

[0053] [(B) Organohydrogenpolysiloxane] Component (B) is an organohydrogenpolysiloxane having at least two hydrosilyl groups at the ends of its molecular chain. It is also preferable that component (B) is an organohydrogenpolysiloxane having two hydrosilyl groups at the ends of its molecular chain and preferably 0 to 10, more preferably 0 to 4, hydrosilyl groups in its side chain. It is preferable that component (B) has one hydrosilyl group at each of its two ends.

[0054] Component (B) can undergo an addition reaction with the alkenyl group of component (A) in the presence of the platinum group metal catalyst (E), described later, to form a sylalkylene structure.

[0055] (B) The molecular structure of component (B) is not particularly limited as long as it has the above properties, and examples include a linear structure, a branched chain structure, or a linear structure having a partially branched or cyclic structure. A linear structure is preferred.

[0056] Component (B) preferably has a kinematic viscosity of 1 to 1,000 mm at 25°C. ２ / s, more preferably 2 to 100 mm ２ The kinematic viscosity is 1 mm². ２ If the temperature is 1 / s or higher, the physical properties of the thermosoftening, thermally conductive silicone composition will be good, and 1,000 mm ２ If the value is less than or equal to / s, the extensibility of the thermosoftening, thermally conductive silicone composition will be sufficient.

[0057] The organic group bonded to the silicon atom of component (B) preferably includes a monovalent aromatic hydrocarbon group having 6 to 10 carbon atoms, and preferably does not include groups that have hydrosilylation reactivity, such as alkenyl groups or alkynyl groups.

[0058] Furthermore, groups other than the monovalent aromatic hydrocarbon group are preferably alkyl groups, more preferably C1 to C12 alkyl groups, and more preferably C1 to C10 alkyl groups. Examples include methyl groups, ethyl groups, propyl groups, butyl groups, hexyl groups, and dodecyl groups. It is also possible to use alkyl groups in which some of the hydrogen atoms are substituted with halogen atoms. Among these, the methyl group is preferred.

[0059] (B) Component may be used alone or in combination of two or more types.

[0060] The amount of component (B) is such that the number of moles of hydrosilyl groups in component (B) is 0.1 to 3 moles per mole of alkenyl groups in component (A), preferably 0.5 to 3 moles, and more preferably 0.7 to 2 moles. If the amount of component (B) is less than the lower limit, the addition reaction will not proceed sufficiently, and crosslinking will be insufficient. If it exceeds the upper limit, the crosslinking structure may become non-uniform, or the long-term stability of the heat-softening, heat-conductive silicone composition may deteriorate.

[0061] [(C) One or more selected from the group consisting of organopolysiloxanes having hydrolyzable functional groups and alkoxysilane compounds represented by general formula (2)] Component (C) is one or more selected from the group consisting of organopolysiloxanes having hydrolyzable functional groups and alkoxysilane compounds represented by the following general formula (2). R ３ ｂ R ４ ｃ Si ( OR ５ ) ４－ｂ－ｃ (2)

[0062] It is preferable that the organopolysiloxane having a hydrolyzable functional group of component (C) is represented by the following general formula (1). (In the formula, R １ R is independently an aromatic hydrocarbon group having 6 to 10 carbon atoms, or independently an alkyl group having 1 to 10 carbon atoms. ２(where a is an alkyl group having 1 to 4 carbon atoms; a is 2 or 3, and n is an integer between 2 and 60; provided that it contains 1% or more of an aromatic hydrocarbon group having 6 to 10 carbon atoms.)

[0063] In the above general formula (1), R １ R is independently a monovalent aromatic hydrocarbon group having 6 to 10 carbon atoms, or independently an alkyl group having 1 to 10 carbon atoms. １ Specific examples include aryl groups such as phenyl, tolyl, xyl, and mesityl groups, and alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, tert-butyl, pentyl, hexyl, octyl, nonyl, and decyl groups. Among these, phenyl and methyl groups are preferred from the viewpoint of ease of synthesis.

[0064] In the above general formula (1), R ２ R is an alkyl group having 1 to 4 carbon atoms, preferably an alkyl group having 1 to 2 carbon atoms. ２ Examples of alkyl groups include methyl, ethyl, propyl, isopropyl, butyl, and tert-butyl groups. Among these, methyl and ethyl groups are particularly preferred from the viewpoint of hydrolysis of organopolysiloxanes having hydrolyzable functional groups. In addition, in the above general formula (1), a is an integer of 2 or 3, and is preferably 3.

[0065] In the above general formula (1), n ​​is an integer between 2 ≤ n ≤ 60, preferably an integer between 9 ≤ n ≤ 30, and more preferably an integer between 12 ≤ n ≤ 18. Within this range, it is preferable because it exhibits good compatibility with component (A), which is a phenyl-modified organopolysiloxane, and component (B), which is an organohydrogenpolysiloxane.

[0066] In the above general formula (1), the content of aromatic hydrocarbon groups having 6 to 10 carbon atoms is 1% or more, preferably 3% or more.

[0067] The alkoxysilane compound, which is an option for component (C), is represented by the following general formula (2). ３ ｂ R ４ ｃ Si ( OR ５ )４－ｂ－ｃ (2) (wherein, R ３ R is an alkyl group having 6 to 15 carbon atoms, ４ R is an independent monovalent hydrocarbon group having 1 to 15 carbon atoms. ５ (where b is an alkyl group having 1 to 6 carbon atoms, b is an integer from 1 to 3, c is an integer from 0 to 2, and b + c is an integer from 1 to 3.)

[0068] In the above general formula (2), R ３ Examples of alkyl groups having 6 to 15 carbon atoms represented by this R include hexyl, octyl, nonyl, decyl, dodecyl, and tetradecyl groups. ３ If the number of carbon atoms in the alkyl group represented by is outside the range of 6 to 15, the wettability of component (A) will be insufficient, resulting in poor handling.

[0069] In the above general formula (2), R ４ Examples of monovalent hydrocarbon groups represented by include C1-C5 alkyl groups, preferably C1-C3 alkyl groups, C6-C15 aryl groups, preferably C6-C12 aryl groups, C7-C15 aralkyl groups, preferably C7-C12 aralkyl groups. Examples of alkyl groups include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, and neopentyl groups. Examples of aryl groups include phenyl, tolyl, xylyl, naphthyl, and biphenylyl groups. Examples of aralkyl groups include benzyl, phenylethyl, phenylpropyl, and methylbenzyl groups. Among these, methyl, ethyl, propyl, and phenyl groups are preferred.

[0070] In the above general formula (2), R ５ Examples of C1-C6 alkyl groups represented by include methyl, ethyl, propyl, butyl, and hexyl groups.

[0071] The amount of component (C) is 10 to 1,000 parts by mass, preferably 10 to 500 parts by mass, per 100 parts by mass of component (A). If the amount is less than 10 parts by mass, the phase inversion properties will be significantly reduced, and if it exceeds 1,000 parts by mass, the processability will be poor.

[0072] (C) Component may be used alone or in combination of two or more types.

[0073] [(D) One or more selected from the group consisting of metallic gallium and gallium alloys] Component (D) of the composition of the present invention is one or more selected from the group consisting of metallic gallium and gallium alloys, having a melting point of 0 to 70°C, and is a component that is added to impart good thermal conductivity to the cured product obtained from the composition of the present invention.

[0074] As described above, the melting point of component (D) must be in the range of 0 to 70°C. If the melting point is below 0°C after preparing the thermoflexible, thermally conductive silicone composition of the present invention, the liquid microparticles tend to aggregate during long-term storage and transportation, making it relatively difficult to maintain the composition's state at the time of preparation. Conversely, if the melting point exceeds 70°C, it does not melt quickly during the composition preparation process, resulting in poor workability. Furthermore, thinning during heat bonding becomes difficult. In particular, a melting point in the range of 15 to 50°C is more preferable because it facilitates the preparation of the thermoflexible, thermally conductive silicone composition of the present invention, makes handling during long-term storage and transportation easy, and facilitates the formation of thermally conductive pathways through aggregation and linkage of the liquid microparticles of component (D) under the heat treatment conditions during the curing of the composition.

[0075] The melting point of metallic gallium is approximately 29.8°C. Representative gallium alloys include, for example, gallium-indium alloys (e.g., Ga-In, mass ratio = 75.4:24.6, melting point = 15.7°C), gallium-tin alloys, gallium-tin-zinc alloys (e.g., Ga-Sn-Zn, mass ratio = 82:12:6, melting point = 17°C), gallium-indium-tin alloys (e.g., Ga-In-Sn, mass ratio = 21.5:16.0:62.5, melting point = 10.7°C), and gallium-indium-bismuth-tin alloys (e.g., Ga-In-Bi-Sn, mass ratio = 9.4:47.3:24.7:18.6, melting point = 48.0°C).

[0076] This (D) component may be used alone or in combination of two or more types.

[0077] The liquid or solid particles of component (D) present in the thermosoftening, thermally conductive silicone composition of the present invention are generally spherical, although irregularly shaped particles may be included. Furthermore, their average particle size (average primary particle diameter) is preferably 0.1 to 100 μm, particularly 5 to 50 μm. If the average particle size is 0.1 μm or more, the viscosity of the composition becomes appropriate, preventing a decrease in compressibility. If it is 100 μm or less, the composition becomes uniform, preventing sedimentation of liquid particles during long-term storage. The particle size can be measured, for example, by laser diffraction scattering.

[0078] The amount of component (D) is 300 to 5,000 parts by mass, preferably 500 to 4,500 parts by mass, and particularly preferably 1,000 to 4,000 parts by mass, per 100 parts by mass of component (A). If the amount is less than 300 parts by mass, it becomes difficult to form a heat conduction path, and a sufficient heat conduction effect may not be obtained. If the amount is more than 5,000 parts by mass, it becomes difficult to disperse and mix component (D) in component (A), etc., to form a uniform composition, and the viscosity of the composition becomes too high, which reduces compressibility and makes it difficult to form a thin film or reduce thermal resistance.

[0079] [(E) Platinum Group Metal Catalyst] Component (E) is a platinum group metal catalyst that functions to promote the addition reaction of components (A) and (B) described above. Conventional platinum group metal catalysts used in addition reactions can be used. Examples include platinum-based, palladium-based, and rhodium-based catalysts, but platinum or platinum compounds, which are relatively easy to obtain, are preferred. Examples include elemental platinum, platinum black, chloroplatinic acid, platinum-olefin complexes, platinum-alcohol complexes, and platinum coordination compounds. A single platinum group metal catalyst or a combination of two or more may be used.

[0080] The amount of component (E) is 0.01 to 1,000 ppm, preferably 10 to 1,000 ppm, based on the mass of platinum group metal atoms relative to the mass of component (A). If the amount of catalyst is less than the lower limit, the catalytic effect may not be obtained. Conversely, exceeding the upper limit does not increase the catalytic effect and is uneconomical, so it is undesirable.

[0081] [(F) Non-reactive phenyl-modified organopolysiloxane] In the thermosoftening, thermally conductive silicone composition of the present invention, in addition to the essential components (A) to (E) above, a non-reactive phenyl-modified organopolysiloxane that does not undergo hydrosilylation reactions with components (A) and (B) or condensation reactions with component (C) may be used as an optional component. That is, it is preferable that the thermosoftening, thermally conductive silicone composition further contains a non-reactive phenyl-modified organopolysiloxane as component (F). Note that component (F) is different from component (A). The molecular structure of component (F) is not particularly limited as long as it has the above properties, and examples include a linear structure, a branched structure, or a linear structure having a partially branched or cyclic structure. A linear structure is preferred.

[0082] Furthermore, component (F) has a phenyl group. The amount of phenyl groups in one molecule is preferably 10 to 100%, and more preferably 30 to 100%, of the number of siloxane units containing a phenyl group per side-chain siloxane unit. If the amount of phenyl groups in one molecule is 10% or more relative to the side-chain siloxane units, the change in viscosity at temperature of the thermo-softening, thermo-conductive silicone composition and the cured product is favorable.

[0083] Furthermore, the non-reactive phenyl-modified organopolysiloxane may have groups other than the phenyl group. From the viewpoint of viscosity, the groups other than the phenyl group are preferably C1 to C18 alkyl groups, preferably C1 to C10 alkyl groups, and more preferably C1 to C8 alkyl groups. Examples include methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, pentyl group, neopentyl group, hexyl group, cyclohexyl group, octyl group, nonyl group, decyl group, etc. It should be noted that alkyl groups in which some of the hydrogen atoms are substituted with halogen atoms may also be used. Among the alkyl groups, the methyl group is particularly preferred.

[0084] Furthermore, non-reactive phenyl-modified organopolysiloxanes have a kinematic viscosity of 100 to 100,000 mmHg at 25°C. ２ It is preferably / s, and more preferably 300 to 10,000 mm ２ / s, and more preferably 400 to 5,000 mm ２ It is / s. The kinematic viscosity is 100 mm ２ A value of 1 / s or higher is preferable because it indicates a sufficient phenyl modification rate. Also, a kinematic viscosity of 100,000 mm² is preferable. ２ A value of / s or less is preferable because it facilitates the handling of the thermosoftening, thermally conductive silicone composition.

[0085] The amount of component (F) is preferably 1 to 500 parts by mass, and more preferably 10 to 100 parts by mass, per 100 parts by mass of component (A). Such an amount is preferable because it allows for a reduction in viscosity of the composition and its cured product without reducing processability.

[0086] (F) Component may be used alone or in combination of two or more types.

[0087] [Other Components] Depending on the purpose and effects of the present invention, other components may be further added to the heat-softening, heat-conductive silicone composition of the present invention. For example, optional components such as hydrosilylation reaction regulators; heat-resistant improvers such as iron oxide; viscosity modifiers such as silica; dilution solvents for lower viscosity; release agents; and other heat-conductive fillers may be added.

[0088] <Other Thermally Conductive Fillers> The thermally softening thermally conductive silicone composition of the present invention may optionally contain, along with component (D), conventionally known thermally conductive fillers used in thermally conductive sheets or thermally conductive greases. These fillers are not particularly limited as long as they have good thermal conductivity; all conventionally known fillers can be used, such as aluminum powder, zinc oxide powder, alumina powder, boron nitride powder, aluminum nitride powder, silicon nitride powder, copper powder, silver powder, diamond powder, nickel powder, zinc powder, stainless steel powder, carbon powder, etc. They can be used individually or in combination of two or more.

[0089] However, if a material with high reactivity with gallium, such as aluminum, is used, aggregation may occur during the mixing process when preparing the composition, making it difficult to achieve a uniform composition. In this case, the liquid fine particles of component (D) should first be uniformly dispersed in component (A), and after component (D) is coated with component (A), the other thermally conductive filler (D) should be added and the mixture mixed. This prevents the composition from becoming non-uniform.

[0090] The average particle size of other thermally conductive fillers is usually in the range of 0.1 to 100 μm, preferably 1 to 20 μm. If the average particle size is less than 0.1 μm, the viscosity of the resulting composition will be too high, resulting in poor compressibility. If it is greater than 100 μm, it becomes difficult to obtain a uniform composition. The particle size can be measured, for example, by laser diffraction scattering.

[0091] The amount of other thermally conductive fillers added is 1,000 parts by mass or less per 100 parts by mass of component (A), and is particularly preferably 500 parts by mass or less. If the amount added exceeds 1,000 parts by mass, the resulting composition will have poor compressibility. Furthermore, it will also inhibit the aggregation of the liquid fine particles of component (D), making it difficult to form the desired thermally conductive pathways, thus reducing the heat dissipation performance of the cured layer obtained from the thermally softening thermally conductive silicone composition of the present invention.

[0092] [Method for Manufacturing a Thermosoftening Thermal Conductive Silicone Composition] An example of a method for manufacturing a thermosoftening thermal conductive silicone composition according to the present invention will be described below. However, the method for manufacturing a thermosoftening thermal conductive silicone composition according to the present invention is not particularly limited.

[0093] Examples of manufacturing methods include mixing the components (A) to (E) mentioned above, and component (F) and other components as needed, using mixers such as a rotation / revolution type mixer (product name: Awatori Rentaro, manufactured by THINKY Co., Ltd.), Trimix, Twinmix, Planetary Mixer (all manufactured by Inoue Seisakusho Co., Ltd.), Ultra Mixer (Mizuho Industries Co., Ltd.), Hibiscus Disper Mix (Tokushu Kika Kogyo Co., Ltd.), etc. Furthermore, all components may be mixed at once, or one or more components may be mixed in several stages.

[0094] In the present invention, it is preferable to first mix components (A), (C), and (D) at room temperature, and then mix in components (B) and (E), as well as component (F) and other components if present. If necessary, heating may be performed during mixing.

[0095] [Heat-softening thermally conductive silicone cured product] Furthermore, the present invention provides a heat-softening thermally conductive silicone cured product characterized in that it is obtained by curing the heat-softening thermally conductive silicone composition of the present invention described above.

[0096] As explained earlier, the heat-softening, heat-conductive silicone cured product of the present invention exhibits excellent heat softening properties, excellent reworkability, and excellent compressibility, thereby achieving low thermal resistance.

[0097] [Method for producing a heat-softening, thermally conductive silicone cured product] The heat-softening, thermally conductive silicone cured product of the present invention can be obtained, for example, by heating the heat-softening, thermally conductive silicone composition of the present invention at a temperature of 40 to 180°C, preferably 60 to 150°C, and more preferably 80 to 120°C, which causes a hydrosilylation reaction between component (A) and component (B).

[0098] The present invention will be specifically described below using examples and comparative examples, but the present invention is not limited to these.

[0099] Preparation of a heat-softening, heat-conductive silicone composition The components (A) to (F) used in the following examples and comparative examples are shown below. Me represents a methyl group, Ph represents a phenyl group, and Vi represents a vinyl group.

[0100] (A) Component (A-1): A component with a kinematic viscosity of 2,000 mm², represented by the following formula. ２ / s phenyl-modified organopolysiloxane (phenyl modification rate: 66%)

[0101] (A-2): The kinematic viscosity is 700 mm, as expressed by the following formula. ２ ・s －１ Phenyl-modified organopolysiloxane (phenyl modification rate: 23%)

[0102] (A-3): The kinematic viscosity is 600 mm, as expressed by the following formula. ２ / s organopolysiloxane <for comparison>

[0103] (A-4): Silicone resin represented by the following formula <for comparison>: kinematic viscosity of 100,000 mm ２ D exceeding / s ２５ T Φ ５５ D Ｖｉ ２０ However, D is Me ２ SiO ２／２ , TΦ PhSiO ３／２ , D Ｖｉ is ViMeSiO ２／２ That is the case.

[0104] (B) Component (B-1): Represented by the following formula, with a kinematic viscosity of 4 mm ２ Phenyl-modified organohydrogenpolysiloxane having hydrosilyl groups at both ends of the molecular chain of / s

[0105] (B-2): The kinematic viscosity is 20 mm, as expressed by the following formula. ２ Phenyl-modified organohydrogenpolysiloxane having hydrosilyl groups at both ends of the molecular chain and in the side chain of / s

[0106] (B-3): The kinematic viscosity is 20 mm, as expressed by the following formula. ２ Phenyl-modified organohydrogenpolysiloxane with a hydrosilyl group in the side chain of / s <for comparison>

[0107] (C) Component (C-1): Hydrolyzable organopolysiloxane represented by the following formula (aromatic hydrocarbon group content: 8.3%)

[0108] (C-2): Decyltrimethoxysilane represented by the following formula

[0109] (D) Component (D-1) Metallic gallium [Melting point = 29.8°C] (D-2) Ga-In alloy [Mass ratio = 75.4:24.6, Melting point = 15.7°C] (D-3) Ga-In-Bi-Sn alloy [Mass ratio = 9.4:47.3:24.7:18.6, Melting point = 48.0°C] (D-4) Metallic indium [Melting point = 156.2°C, Average particle size: 23 μm] <For comparison> Note that the average particle size of component (D-4) was measured by laser diffraction scattering using a particle size distribution analyzer MT3000II (manufactured by Microtrac-Bell Co., Ltd.).

[0110] (E) Component (E-1) 5% 2-ethylhexanol chloroplatinate solution

[0111] (F) Component (F-1) A component with a kinematic viscosity of 380 mm², represented by the following formula. ２ / s phenyl-modified organosiloxane

[0112] (G) Other components (G-1): Zinc oxide powder [Average particle size: 1.0 μm] The average particle size is the volume-based cumulative 50% particle size (D50) value measured by a Microtrac-Bell particle size distribution analyzer MT3000II.

[0113] [Manufacturing Method] Manufacturing of thermosoftening, thermally conductive silicone compositions and cured products Components (A) to (F) were mixed as follows to obtain the compositions of the Examples and Comparative Examples, and each composition was cured to obtain the thermosoftening, thermally conductive silicone cured products of the Examples and Comparative Examples.

[0114] Component (A), (C), (D), and (F) were weighed into a metal vessel in the composition ratios (parts by mass) shown in Table 1, and stirred for 1 hour at room temperature and 30 rpm using a planetary mixer (manufactured by Inoue Seisakusho Co., Ltd.). Then, component (E) was added and stirred for 30 minutes at room temperature and 30 rpm. Furthermore, component (B) was added and stirred for 20 minutes at room temperature and 30 rpm to obtain the respective thermoplastic and thermally conductive silicone compositions for the examples and comparative examples. After that, each composition was stirred at 100°C and 30 rpm for 1 hour, and then cooled to room temperature to obtain the respective thermoplastic and thermally conductive silicone cured products.

[0115] Furthermore, components (D-1), (D-2), and (D-3) were melted in advance at a temperature above their melting point and then blended together with components (A), (C), and (F) in a liquid state.

[0116] The average particle size of the liquid or solid fine particles of metallic gallium and / or gallium alloy present in the composition was obtained by dispersing a small amount of the composition in a large excess of toluene and measuring the particle size distribution of the particles contained in the dispersion using a particle size distribution analyzer MT3000II (manufactured by Microtrac-Bell Co., Ltd.) by laser diffraction scattering.

[0117] [Evaluation Method] Thermal softening and reworkability of the thermal softening and thermal conductive silicone compositions A portion of each thermal softening and thermal conductive silicone composition from Examples 1 to 3 before curing was taken and heated at 100°C for 1 hour. As a result, it was confirmed that the thermal softening and thermal conductive silicone compositions of Examples 1 to 3 have excellent thermal softening properties.

[0118] Furthermore, a portion of each of the thermosoft, thermally conductive silicone compositions from Examples 1 to 3, before curing, was applied to a thickness of 200 μm, attached to a module or aluminum plate, and left to stand for 24 hours. After that, the cured material was wiped off with a plastic spatula or paper towel without using a solvent. As a result, it was confirmed that each of the thermosoft, thermally conductive silicone compositions from Examples 1 to 3 could be sufficiently wiped off without a solvent. In other words, the thermosoft, thermally conductive silicone compositions from Examples 1 to 3 had excellent reworkability.

[0119] The thickness of the heat-softening, thermally conductive silicone cured material after heating and pressing was measured. The heat-softening, thermally conductive silicone cured material was applied to a nickel plate to a thickness of 200 μm, and a nickel plate was bonded on top, sandwiching each of the heat-softening, thermally conductive silicone cured materials between the two nickel plates. The heat-softening, thermally conductive silicone cured material sandwiched between the two nickel plates was heated at 80°C for 60 minutes while applying a pressure of 137.9 kPa using a clip or the like. The heat-softening, thermally conductive silicone cured materials of Examples 1 to 3 showed sufficient thermal softening properties. After cooling to room temperature, the thickness of the heat-softening, thermally conductive silicone cured material sandwiched between the two nickel plates was measured. A micrometer (Mitutoyo Corporation, Model: M802-25VA) was used for thickness measurement. Furthermore, the thermal resistance of the heat-softening, thermally conductive silicone cured product was measured using a laser flash measuring instrument (NETZSCH, LFA467 HyperFlash). The results are shown in Table 1. In the present invention, the thickness of the heat-softening, thermally conductive silicone cured product after heat bonding is preferably 30 μm or less, and the thermal resistance is 10 mm. ２ - Preferably less than kW, and more preferably 5 mm ２ It is below kW.

[0120] [Reworkability] Wiping property Each of the thermoplastic thermally conductive silicone cured products obtained as described above was applied so as to have a thickness of 200 μm, pasted onto a module or an aluminum plate, and allowed to stand for 24 hours. Thereafter, the cured product was wiped with a plastic spatula or a paper towel without using a solvent, and judged as follows. The results are shown in Table 1. 〇: Can be wiped without solvent ×: Cannot be wiped without solvent

[0121]

[0122] In the table, the composition of each component is in parts by mass. Further, H / Vi is the molar ratio of the hydrosilyl group in component (B) to the alkenyl group (vinyl group) in component (A).

[0123] As in Examples 1 to 3, a phenyl-modified organopolysiloxane as component (A), an organohydrogenpolysiloxane having at least two hydrosilyl groups at the terminals as component (B), and an organopolysiloxane having a hydrolyzable functional group and the general formula (2): R ３ ｂ R ４ ｃ Si(OR ５ ) ４－ｂ－ｃ The thermoplastic thermally conductive silicone composition and its cured product using one or more selected from the group consisting of alkoxysilane compounds represented by showed excellent thermoplasticity as described above. Further, it was found that the thermoplastic thermally conductive silicone compositions and their cured products of Examples 1 to 3 were capable of being wiped under conditions without using a solvent and were excellent in reworkability. Furthermore, the thermoplastic thermally conductive silicone compositions and their cured products of Examples 1 to 3 were capable of being thinned and having reduced thermal resistance under low pressure and low temperature conditions by blending a metal gallium and / or a gallium alloy having a melting point of 0 to 70°C as component (D).

[0124] On the other hand, as in Comparative Example 1, when a metal with a high melting point ((D-4) metallic indium) was incorporated, the compressibility at low temperatures and pressures was poor, and thinning and low thermal resistance could not be achieved. Also, as in Comparative Example 2, when the amount of metallic gallium, a low melting point metal, as component (D) was too high, it was difficult to formulate the composition. Furthermore, as in Comparative Example 3, when an organohydrogenpolysiloxane having hydrosilyl groups only in the side chains was used as component (B), the cured product was hard and its compressibility decreased. Also, when the cured product was molded into a 200 μm sheet, the sheet was brittle and difficult to handle. Moreover, as in Comparative Example 4, when an organopolysiloxane without phenyl groups was used as component (A), the composition and cured product lacked thermal softening properties, resulting in decreased compressibility at low temperatures and pressures and increased thermal resistance. Furthermore, as in Comparative Example 5, when a thermoplastic silicone resin having T units was used for component (A), the composition exhibited the same thermal softening properties as in Example 1, but it was found that wiping without a solvent was difficult and the reworkability decreased. This is thought to be because the use of thermoplastic silicone resin results in greater tackiness derived from the silicone resin.

[0125] From these results, it was found that the heat-softening, thermally conductive silicone cured product according to the present invention exhibits good heat softening properties and excellent reworkability. Furthermore, it was shown that it exhibits good compressibility even under low temperature and low pressure conditions, enabling thinning and low thermal resistance.

[0126] This specification includes the following embodiments: [1] A thermosoftening, thermally conductive silicone composition characterized by comprising the following components (A) to (E): (A) Having two or more alkenyl groups in one molecule and having a kinematic viscosity of 100 to 100,000 mm at 25°C ２Phenyl-modified organopolysiloxane having a viscosity of / s: 100 parts by mass, (B) Organohydrogenpolysiloxane having at least two hydrosilyl groups at the molecular chain ends, in an amount such that the molar number of hydrosilyl groups in component (B) is 0.1 to 3 moles relative to 1 mole of the alkenyl group possessed by component (A), (C) Organopolysiloxane having a hydrolyzable functional group, and at least one selected from the group consisting of alkoxysilane compounds represented by the following general formula (2): 10 to 1,000 parts by mass, R ３ ｂ R ４ ｃ Si(OR ５ ) ４－ｂ－ｃ (2) (In the formula, R ３ is independently an alkyl group having 6 to 15 carbon atoms, R ４ is independently a monovalent hydrocarbon group having 1 to 15 carbon atoms, R ５ is independently an alkyl group having 1 to 6 carbon atoms, b is an integer of 1 to 3, c is an integer of 0 to 2, provided that b + c is an integer of 1 to 3.) (D) One or more selected from the group consisting of metallic gallium and gallium alloys having a melting point of 0 to 70°C: 300 to 5,000 parts by mass, (E) Platinum group metal catalyst: 0.01 to 1,000 ppm on a mass basis in terms of platinum group metal atoms relative to the mass of component (A). [2] The thermoplastic thermally conductive silicone composition according to [1], wherein the organopolysiloxane having a hydrolyzable functional group as component (C) is represented by the following general formula (1). (In the formula, R １ is independently an aromatic hydrocarbon group having 6 to 10 carbon atoms, or independently an alkyl group having 1 to 10 carbon atoms, R ２(1) is an alkyl group having 1 to 4 carbon atoms. a is 2 or 3, and n is an integer between 2 and n ≤ 60. (However, it contains 1% or more of an aromatic hydrocarbon group having 6 to 10 carbon atoms.) [3] The thermosoftening thermoconductive silicone composition according to [1] or [2], characterized in that the thermosoftening thermoconductive silicone composition further contains a nonreactive phenyl-modified organopolysiloxane as component (F). [4] The thermosoftening thermoconductive silicone composition according to [3], characterized in that it contains 1 to 500 parts by mass of component (F) per 100 parts by mass of component (A). [5] A thermosoftening thermoconductive silicone cured product, characterized in that it is a thermosoftening thermoconductive silicone composition according to any one of [1] to [4] that has been cured.

[0127] It should be noted that the present invention is not limited to the embodiments described above. The embodiments described above are illustrative, and any configuration that is substantially identical to the technical idea described in the claims of the present invention and achieves similar effects is included within the technical scope of the present invention.

Claims

1. A thermoplastic thermally conductive silicone composition, characterized by comprising the following components (A) to (E). (A) A phenyl-modified organopolysiloxane having two or more alkenyl groups in one molecule and a kinematic viscosity at 25°C of 100 to 100,000 mm ２ / s: 100 parts by mass, (B) An organohydrogenpolysiloxane having at least two hydrosilyl groups at the molecular chain ends, in an amount such that the molar number of hydrosilyl groups in component (B) is 0.1 to 3 moles per mole of alkenyl groups in component (A), (C) One or more selected from the group consisting of an organopolysiloxane having a hydrolyzable functional group and an alkoxysilane compound represented by the following general formula (2): 10 to 1,000 parts by mass, R ３ ｂ R ４ ｃ Si(OR ５ ) ４－ｂ－ｃ (2) (In the formula, R ３ is independently an alkyl group having 6 to 15 carbon atoms, R ４ is independently a monovalent hydrocarbon group having 1 to 15 carbon atoms, R ５ is independently an alkyl group having 1 to 6 carbon atoms, b is an integer of 1 to 3, c is an integer of 0 to 2, provided that b + c is an integer of 1 to 3.) (D) One or more selected from the group consisting of metallic gallium and gallium alloys having a melting point of 0 to 70°C: 300 to 5,000 parts by mass, (E) A platinum group metal catalyst: 0.01 to 1,000 ppm on a mass basis in terms of platinum group metal atoms relative to the mass of component (A).

2. The thermosoftening, thermally conductive silicone composition according to claim 1, characterized in that the organopolysiloxane having a hydrolyzable functional group of component (C) is represented by the following general formula (1). (In the formula, R １ R is independently an aromatic hydrocarbon group having 6 to 10 carbon atoms, or independently an alkyl group having 1 to 10 carbon atoms. ２ (where a is an alkyl group having 1 to 4 carbon atoms; a is 2 or 3, and n is an integer between 2 and 60; provided that it contains 1% or more of an aromatic hydrocarbon group having 6 to 10 carbon atoms.) 3. The thermosoftening, thermally conductive silicone composition according to claim 1, characterized in that the thermosoftening, thermally conductive silicone composition further contains a non-reactive phenyl-modified organopolysiloxane as component (F).

4. The thermosoftening, thermally conductive silicone composition according to claim 3, characterized in that it contains 1 to 500 parts by mass of component (F) per 100 parts by mass of component (A).

5. A heat-softening, heat-conducting silicone cured product, characterized in that it is a heat-softening, heat-conducting silicone composition according to any one of claims 1 to 4 that has been cured.

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