Thermally conductive composition, thermally conductive member, and heat dissipation structure

Abstract

[Problem] To provide: a thermally conductive composition which has very high thermal conductivity, excellent extrusion workability, excellent filling properties into small-capacity packages, and the like, and which is suppressed in changes in hardness and deterioration in heat dissipation performance after heat aging; a thermally conductive member formed from the thermally conductive composition; and a heat dissipation structure using the thermally conductive member. [Solution] A thermally conductive composition characterized by comprising (A) one or more matrix polymers having a viscosity in the range of 10-1,000,000 mPas at 25 DEG C, (B) one or more thermally conductive fillers, (C) an organopolysiloxane represented by general formula (1) (in the formula, R1 is a monovalent hydrocarbon group having no carbon-carbon double bond, R2 is a hydrogen atom or the like, a is a number of 40-90, and b is a number of 1-3), and (C) a solvent, and a solvent, the content of the component (B) is in the range of 60-95 vol% with respect to the total solid content in the composition. (1)

Description

Technical Field

[0001] This invention relates to a thermally conductive composition, a thermally conductive component thereof, and a heat dissipation structure using the same. The thermally conductive composition has a very high thermal conductivity, and the cured product has practically sufficient softness and stress relief properties. Even under high-temperature heating and aging, the hardness of the cured product changes little, maintaining its softness. Therefore, it can maintain good heat dissipation characteristics for heat dissipation parts for a long time. Furthermore, the thermally conductive composition has good extrudability and ejection properties from cartridges, etc. In addition to its filling properties for small-capacity packaging, it also has excellent work efficiency during coating. Background Technology

[0002] In recent years, with the increasing density and high integration of printed circuit boards (PCBs) housing electronic components such as transistors, ICs, and memory elements, the growing capacity of hybrid ICs, and the increasing capacity of secondary batteries (cell-type), thermally conductive silicone compositions composed of organopolysiloxanes and thermally conductive fillers such as alumina powder, aluminum hydroxide powder, and zinc oxide powder have been widely used to efficiently dissipate heat generated by electronic components, batteries, and other electronic and electrical devices. These thermally conductive silicone compositions exhibit excellent heat resistance, and even when the thermally conductive filler is formulated at high concentrations and high volume percentages, the cured product remains rubbery. Therefore, a certain degree of flexibility and stress mitigation is desirable, enabling them to maintain the ability to follow and adhere to heat sources within the heat dissipation structure, thus preserving heat dissipation performance.

[0003] In recent years, to address the issue of high heat dissipation, thermally conductive organosilicon compositions filled with a large amount of thermally conductive filler have been proposed. In particular, in recent years, boron nitride powder has been proposed as a thermally conductive filler with excellent thermal conductivity (e.g., Patent Document 1, etc.).

[0004] However, in these thermally conductive silicone compositions containing thermally conductive fillers, the addition of large amounts of thermally conductive fillers such as aluminum nitride powder often tends to impair the rubber properties of the cured silicone polymer. Excessive amounts of thermally conductive fillers result in an overly hard cured product, creating gaps between the product and the heat dissipation target, impairing conformability and stress relief, and sometimes failing to achieve adequate heat dissipation. In other words, controlling the hardness of the cured thermally and electrically conductive silicone composition is a crucial technical issue for achieving good heat dissipation. Furthermore, the addition of large amounts of thermally conductive fillers such as aluminum nitride powder tends to impair the flowability of the composition itself. When filling cartridges and dispensing machines for small-volume or precise coating purposes, it is sometimes impossible to ensure sufficient extrusion volume, especially for small-volume packaging, which can become difficult, or reduce the workability and coating properties after filling, thus reducing operational efficiency. In addition, sometimes it is impossible to uniformly disperse the thermally conductive filler in the silicone composition, which can adversely affect the expected thermal conductivity, curability, and operability in commercial production. Therefore, silicone compositions with high thermal conductivity, especially those with thermally conductive fillers such as aluminum nitride powder and having a thermal conductivity of 9.0 W / mK or higher, have room for improvement in terms of performance and operability for industrial application.

[0005] On the other hand, to adjust the viscosity and plasticity of thermally conductive fillers, the use of methyl polysiloxanes (sometimes referred to as "macromonomer-type treatment agents") with a single terminal trifunctional hydrolyzable group in thermally conductive silicone rubber compositions has been proposed (Patent Documents 2 to 9). These documents propose a method to suppress the increase in viscosity and plasticity of thermally conductive compositions containing a large amount of thermally conductive filler by heating and mixing (sometimes referred to as "base compositions") of a mixture containing a matrix polymer as a main agent, a thermally conductive filler, and their macromonomer-type treatment agents at high temperatures and then cooling it. The degree of polymerization of these siloxanes is disclosed as ranging from 5 to 100 or from 100 to 200. However, the examples in these documents only use substances with a degree of polymerization of about 30 or greater than 100, and there is no record or suggestion regarding the significance of limiting the degree of polymerization to a specific range, particularly regarding its effects on extrusion operability, heat aging properties of the cured product, and thermal conductivity.

[0006] In addition, there is no record or suggestion in the literature regarding the further adjustment of the hardness of the cured product by adjusting fatty acids and the like in the hydrosilylation curing organosilicon compositions, or the combined use with heat-resistant agents such as phthalocyanine compounds.

[0007] Existing technical documents

[0008] Patent documents

[0009] Patent Document 1: Japanese Patent Application Publication No. 07-330927

[0010] Patent Document 2: Japanese Patent Application Publication No. 2000-256558 (Patent Grant No. 3543663)

[0011] Patent Document 3: International Publication No. 2002 / 092693 (US Patent No. 7329706)

[0012] Patent Document 4: International Publication No. 2022 / 249754

[0013] Patent Document 5: Japanese Patent Application Publication No. 2017-75202 (Patent Grant No. 6524879)

[0014] Patent Document 6: International Publication No. 2018 / 093030 (Booklet)

[0015] Patent Document 7: International Publication No. 2015 / 040777

[0016] Patent Document 8: Japanese Patent Application Publication No. 2021-113290 (Patent Grant No. 7306278)

[0017] Patent Document 9: International Publication No. 2019 / 093052 Summary of the Invention

[0018] The problem that the invention aims to solve

[0019] Furthermore, the inventors of this application have discovered new technical problems in thermally conductive silicone compositions that cure via hydrosilylation. As described above, when a thermally conductive silicone composition containing a large amount of thermally conductive filler is cured, the cured product tends to harden, and high thermal conductivity and the softness of the cured product are mostly in a trade-off. However, even when the hardness and thermal conductivity of the cured product are adjusted to design the thermally conductive silicone composition, in the case of a high heat dissipation composition containing the thermally conductive filler described above at a very high volume percentage (e.g., 60% or more relative to the total solid content of the composition), the cured product sometimes hardens rapidly after heat aging and loses its softness and rubber elasticity. Sometimes stress relief, conformability in the heat dissipation structure, and adhesion are impaired. Consequently, the originally intended heat dissipation characteristics are sometimes not fully realized.

[0020] The present invention was made to solve the above-mentioned problems, and its object is to provide a thermally conductive composition, a thermally conductive component composed therefrom, and a heat dissipation structure using the same. The thermally conductive composition contains thermally conductive fillers such as aluminum nitride powder in a very high volume percentage, thus having high thermal conductivity. The thermally conductive component composed of the cured product has practically sufficient flexibility and stress relief characteristics. Even when heated and aged at high temperatures, the hardness of the cured product changes little, and it can maintain flexibility. Therefore, it can maintain good heat dissipation characteristics for heat dissipation parts for a long time. Furthermore, the thermally conductive composition is easy to extrude from cartridges, dispensing machines, etc., and has excellent filling, handling, and coating properties, especially for small-capacity packaging.

[0021] Solution for solving the problem

[0022] The inventors conducted in-depth research and discovered that the above-mentioned problems can be solved by the following thermally conductive composition, thereby completing the present invention. The thermally conductive composition is characterized by comprising:

[0023] (A) One or more matrix polymers having a viscosity in the range of 10 to 1,000,000 mPa·s at 25°C.

[0024] (B) One or more thermally conductive fillers,

[0025] (C) General formula (1):

[0026] [Chemical Formula 1]

[0027]

[0028] (where R) 1 R is an independent, unsubstituted or substituted monovalent hydrocarbon group without a carbon-carbon double bond. 2 Organopolysiloxanes, which are independently composed of hydrogen atoms, alkyl groups, alkoxyalkyl groups, or acyl groups, where a is a number from 40 to 90 and b is a number from 1 to 3.

[0029] The content of component (B) is in the range of 60 to 95% by volume relative to the total solid components in the composition. That is, this composition is a thermally conductive composition containing a large amount (specifically, in the range of 60 to 95% by volume relative to the total solid components in the composition) of thermally conductive fillers such as aluminum nitride powder in order to impart high thermal conductivity. However, by selectively using organopolysiloxanes with a specific degree of siloxane polymerization as shown in general formula (1), it is possible to achieve both extremely high thermal conductivity and coating and workability of the composition itself, which have usually been compromised. Furthermore, when the composition is curable reactive, in addition to its softness (= rubber properties), the hardness of the cured product changes little even when heated and aged at high temperatures, and it can maintain its softness. Therefore, it is possible to simultaneously achieve good heat dissipation characteristics for heat dissipation parts over a long period of time. In addition, this composition has particularly excellent extrusion workability from small-capacity packaging.

[0030] It should be noted that the composition may further contain a certain amount of a surface treatment agent as other organosilicon compounds; at least one fatty acid compound selected from fatty acids, fatty acid esters, and fatty acid metal salts; and a heat resistance imparting agent (preferably phthalocyanine compounds and / or carbon black). Furthermore, in preparing the composition, the matrix polymer (preferably organopolysiloxane), the thermally conductive filler, and the component that functions as a specific surface treatment agent (the aforementioned component (C)) can be mixed together and heated (basic heating), or the matrix polymer (preferably organopolysiloxane), the thermally conductive filler, and component (C) can be mixed and added to the mixture after basic heating along with other components.

[0031] The effects of the invention

[0032] This invention provides a thermally conductive composition or its cured reactant that can form a thermally conductive composition with a very high thermal conductivity of 9.0 W / mK or higher, and possesses practically sufficient coatability, flexibility, and stress-relieving properties, as well as thermally conductive components formed therefrom. Furthermore, it is extremely easy to extrude from cartridges, dispensing machines, etc., and can be easily filled into small-volume packages such as syringes, exhibiting particularly excellent operability and coatability. Moreover, when the composition is a curing reactive compound, in addition to its flexibility (=rubber properties), even under heat aging at high temperatures, the hardness change of the cured product is small, maintaining flexibility and stress-relieving properties, thus maintaining good heat dissipation characteristics for heat dissipation parts over a long period. In addition, this invention provides the thermally conductive composition or thermally conductive components formed therefrom, and heat dissipation structures using the same components (particularly heat dissipation structures for electrical / electronic components and heat dissipation structures for secondary batteries).

[0033] It should be noted that, for the cured product of the thermally conductive composition of the present invention, by further adding the aforementioned fatty acid-based compounds and heat-resistant agents as needed, the hardness change and cracking during heat aging can sometimes be further improved. Even when applied to heat dissipation objects of various shapes and used for a long time at high temperatures, it is not easy to peel off from the heat-generating component due to vibration or other reasons, or to generate voids (including voids caused by partial / temporary peeling from the component, the same below). It maintains excellent adhesion and conformability, thus having the advantage of not compromising the heat dissipation efficiency in the initial adaptation period. Therefore, compared with conventional products, it has the following advantages: excellent operating efficiency during extrusion, excellent durability and heat dissipation performance of the heat dissipation component, and applicability to heat dissipation objects of various shapes. It is not easy to peel off even when used for assembly / assembly at high temperatures, and it can be used for a long time in the heat dissipation process at high temperatures. Detailed Implementation

[0034] [Thermal Conductive Composition]

[0035] The composition of the present invention comprises a matrix polymer, preferably an organopolysiloxane, a thermally conductive filler, and a macromolecular monomer type treatment agent with a specific degree of polymerization of the siloxane as shown in the above general formula (1), and the amount of the thermally conductive filler is specified in a range. In particular, by selectively using a macromolecular monomer type treatment agent with a specific degree of polymerization of the siloxane, the cured product has extremely high thermal conductivity and rubber properties, and even under heat aging at high temperatures, the hardness of the cured product changes little, maintaining softness and stress relief characteristics, thus maintaining good heat dissipation characteristics for heat dissipation parts for a long time. Furthermore, the thermally conductive composition of the present invention is very easy to extrude from cartridges, dispensing machines, etc., and even in small-volume packaging, it has excellent filling properties, excellent operability, and excellent work efficiency during coating (especially extrusion operability).

[0036] It should be noted that the compositions of the present invention can be used as greases or gap fillers in an uncured state, or they can be curing reactive compositions based on hydrosilylation reactions with a specified SiH / alkene ratio. When the composition has curing reactive properties, it may contain other surface treatment agents; at least one selected from fatty acids, fatty acid esters, and fatty acid metal salts (hereinafter, sometimes referred to as "fatty acid compounds"); and heat resistance imparting agents.

[0037] This composition can be used in an uncured state or as a curing reactive compound. Specifically, component (A) preferably includes one or more organopolysiloxanes with a viscosity at 25°C ranging from 10 to 1,000,000 mPa·s. These organopolysiloxanes can be selected from organopolysiloxanes (A1) that do not have curing reactive groups containing carbon-carbon double bonds and (A2) organopolysiloxanes that do have curing reactive groups containing carbon-carbon double bonds. In a curing reactive composition using component (A2), it may further include (D) an organohydrogen polysiloxane and (E) a catalyst amount for hydrosilylation reactions. (F) a heat-resistant agent and (G) a fatty acid compound can be arbitrarily incorporated. Furthermore, the composition may include hydrosilylation reaction inhibitors, adhesion promoters, organic solvents, and other additives. Moreover, the composition of the present invention can be a single-component composition or a multi-component composition such as a two-component composition. Hereinafter, the components and their amounts will be described.

[0038] The average particle size of each component (including spherical or amorphous) of the thermally conductive filler (B) is given below as the cumulative average particle size D in the particle size distribution based on the volumetric reference of laser diffraction scattering. 50 The median diameter can be determined using a laser diffraction particle size distribution measuring device commonly used in this field. Furthermore, based on the same principle, the content (volume %) of coarse particles below a certain particle size can be determined using a laser diffraction particle size distribution measuring device. Additionally, component (C) described later does not overlap with the organopolysiloxane that is component (A) and is excluded from its range.

[0039] [(A) Matrix polymer]

[0040] Component (A) is a matrix polymer used to carry the thermally conductive filler. It can be any curable or non-curable liquid or fluid polymeric material with a viscosity at 25°C in the range of 10 to 1,000,000 mPa·s, preferably in the range of 10 to 10,000 mPa·s, without particular limitation. For example, organopolysiloxanes, liquid polyurethane resins, liquid polyester resins, liquid acrylic resins, liquid polyol resins, liquid butadiene rubbers, liquid isoprene rubbers, liquid styrene-butadiene rubbers, etc., can be used without limitation. However, from the perspective of application in semiconductor devices and the like that that generate high temperatures, the thermally conductive composition of the present invention particularly preferably contains one or more organopolysiloxanes with excellent heat and cold resistance and a viscosity at 25°C in the range of 10 to 1,000,000 mPa·s (A0).

[0041] The organopolysiloxane (A0) is the main agent of this composition and is one or more organopolysiloxanes with a viscosity at 25°C in the range of 10 mPa·s to 1,000,000 mPa·s. The viscosity of component (A) at 25°C is preferably in the range of 10 to 100,000 mPa·s, more preferably in the range of 10 to 10,000 mPa·s. If the viscosity of component (A) is less than 10 mPa·s, the mechanical strength of the resulting organopolysiloxane composition or its cured form tends to decrease. On the other hand, if the viscosity of component (A) is greater than 100,000 mPa·s, the viscosity of the resulting composition is too high, thus tending to reduce workability and coating properties for fine areas. It should be noted that, from the viewpoint of preventing contact failure, it is preferable to reduce or remove low molecular weight siloxane oligomers (octamethyltetrasiloxane (D4), decamethylpentasiloxane (D5)) from component (A).

[0042] Component (A) may consist of one or more organopolysiloxanes. The molecular structure of such organopolysiloxanes is not particularly limited, and examples include linear, branched, cyclic, three-dimensional network structures (including so-called resin-like three-dimensional structures) and combinations thereof.

[0043] Depending on the presence or absence of curing reactive groups in component (A), this composition can be designed as a curable or non-curable composition. Here, curing reactive groups are functional groups capable of curing the entire composition (including gelation, the same below) through crosslinking reactions. Their type is not particularly limited, but hydrosilylation reactive or free radical polymerization reactive groups are preferred, and curing reactive groups having carbon-carbon double bonds within the molecule are particularly preferred. Furthermore, curing reactive groups having carbon-carbon double bonds within the molecule are preferably at least one organic group selected from alkenyl groups, organic groups containing methacryloyloxy groups, and organic groups containing acryloyloxy groups, and are particularly preferred to be alkenyl groups with 2 to 20 carbon atoms.

[0044] Component (A) is preferably one or more organopolysiloxanes selected from organopolysiloxanes (A1) that do not have curing reactive groups containing carbon-carbon double bonds in their molecules and organopolysiloxanes (A2) that have curing reactive groups containing carbon-carbon double bonds in their molecules. Component (A1) can be used alone, component (A2) alone, or a combination of both. It should be noted that when component (A2) is used in at least a portion of component (A), this composition can be designed to be curable.

[0045] Component (A1) is an organopolysiloxane that does not contain curing reactive groups with carbon-carbon double bonds within its molecule. It is suitable as a main agent in non-curing thermally conductive organopolysiloxane compositions, such as thermally conductive greases and non-curing thermally conductive gap fillers. The functional group in component (A1) is a group other than a curing reactive functional group, and examples include alkyl groups such as methyl; aryl groups such as phenyl; and monovalent hydrocarbon groups other than alkenyl groups such as 3,3,3-trifluoropropyl. Industrially, methyl or phenyl is preferred.

[0046] Particularly preferred component (A1) is a linear, non-curable organopolysiloxane, such as trimethylsiloxy-terminated dimethylpolysiloxane, trimethylsiloxy-terminated dimethylsiloxane / methylphenylsiloxane copolymer, and silanol-terminated dimethylsiloxane copolymer. These polymers are formed by replacing a portion of the methyl group with alkyl groups other than methyl groups such as ethyl or propyl, or haloalkyl groups such as 3,3,3-trifluoropropyl, and mixtures of two or more of these polymers. It should be noted that, as described above, the organopolysiloxanes described later as component (C) are excluded from the scope of component (A), and these components are not repeated.

[0047] Component (A2) is an organopolysiloxane with a curing reactive group having a carbon-carbon double bond in its molecule. The curing reactive group having a carbon-carbon double bond in its molecule has at least one organic group selected from alkenyl, methacryloyloxy, and acryloyloxy organic groups. Therefore, it is suitable as a main agent for curable thermally conductive organopolysiloxane compositions, such as curable thermally conductive elastomers, thermally conductive gels, and curable thermally conductive gap fillers.

[0048] Examples of alkenyl groups within the molecule of component (A2) include vinyl, allyl, butenyl, and hexenyl groups. Furthermore, examples of organic groups other than alkenyl groups in component (A2) include alkyl groups such as methyl; aryl groups such as phenyl; and monovalent hydrocarbon groups other than alkenyl groups such as 3,3,3-trifluoropropyl. Industrially, methyl or phenyl groups are preferred.

[0049] The particularly preferred component (A2) is a linear alkenyl-containing organopolysiloxane, such as dimethylvinylsiloxy-terminated dimethylpolysiloxane, dimethylvinylsiloxy-terminated dimethylsiloxane / methylphenylsiloxane copolymer, trimethylsiloxy-terminated dimethylsiloxane / methylvinylsiloxane copolymer, trimethylsiloxy-terminated dimethylsiloxane / methylvinylsiloxane / methylphenylsiloxane copolymer, silanol-terminated dimethylsiloxane / methylvinylsiloxane copolymer, polymers in which a portion of the methyl group of these polymers is replaced by alkyl groups other than methyl such as ethyl or propyl, or by haloalkyl such as 3,3,3-trifluoropropyl, polymers in which the vinyl groups of these polymers are replaced by alkenyl groups other than vinyl such as allyl, butenyl, or hexenyl, and mixtures of two or more of these polymers.

[0050] When component (A) includes component (A2), the curing agent of the composition may include (D) an organohydrogen polysiloxane and (E) a catalytic amount of a catalyst for hydrosilylation reaction, and is preferred.

[0051] [(D) Organohydrogen polysiloxane]

[0052] Component (D) is the main crosslinking agent of the composition of the present invention. Organohydrogen polysiloxanes having two or more silicon atoms bonded to hydrogen atoms within the molecule can be used without particular limitation. However, from the viewpoint of the softness of the cured product and the retention of adhesion to the substrate, the number (average) of silicon atoms bonded to hydrogen atoms in the molecule of the organohydrogen polysiloxane is preferably not greater than eight. Particularly preferred is a linear organohydrogen polysiloxane containing at least (D1) a viscosity of 1 to 1000 mPa·s at 25°C, an average of 2 to 4 silicon atoms bonded to hydrogen atoms within the molecule, wherein the side chains of the molecular chain have at least an average of one silicon atom bonded to hydrogen atom.

[0053] Such components (D1) can be exemplified by trimethylsiloxy-terminated methylhydrosiloxane / dimethylsiloxane copolymers at both ends of the molecular chain, and dimethylsiloxy-terminated methylhydrosiloxane / dimethylsiloxane copolymers at both ends of the molecular chain. It should be noted that these examples are not limiting, and a portion of the methyl group may also be replaced by phenyl, hydroxyl, alkoxy, etc.

[0054] The viscosity of component (D1) at 25°C is not particularly limited, but is preferably in the range of 1 to 500 mPa·s, and particularly preferably in the range of 1 to 100 mPa·s. Furthermore, from the viewpoint of preventing contact failure, it is preferable to reduce or remove low molecular weight siloxane oligomers (octamethyltetrasiloxane (D4), decamethylpentasiloxane (D5)).

[0055] [Amount of organohydrogen polysiloxane (crosslinking agent) in the composition]

[0056] From the perspective of the rubber properties, mechanical strength, and adhesive properties of the obtained organopolysiloxane cured product, it is particularly preferred that, with respect to component (D), at least relative to 1 mole of alkenyl group contained in component (A), the amount of silicon atoms bonded to hydrogen atoms in component (A) is in the range of 0.2 to 5.0 moles, 0.3 to 3.0 moles, or 0.4 to 2.0 moles.

[0057] [(E) Catalyst for hydrosilylation reaction]

[0058] The catalyst for the hydrosilylation reaction is a component used for curing this composition. Examples of such catalysts include platinum-based catalysts, rhodium-based catalysts, and palladium-based catalysts. From the viewpoint of significantly promoting the curing of this composition, platinum-based catalysts are preferred. Examples of such platinum-based catalysts include platinum micropowder, chloroplatinic acid, alcoholic solutions of chloroplatinic acid, platinum-alkenylsiloxane complexes, platinum-olefin complexes, platinum-carbonyl complexes, and catalysts in which these platinum-based catalysts are dispersed or encapsulated in thermoplastic resins such as silicone resins, polycarbonate resins, and acrylic resins. Platinum-alkenylsiloxane complexes are particularly preferred. 1,3-Divinyl-1,1,3,3-tetramethyldisiloxane complexes of platinum are particularly preferred, and it is preferable to add them in the form of an alkenylsiloxane solution of this complex. In addition, from the viewpoint of improving workability and the pot life of the composition, particulate platinum-containing hydrosilylation reaction catalysts dispersed or encapsulated in thermoplastic resins can also be used. It should be noted that non-platinum metal catalysts such as iron, ruthenium, and iron / cobalt can be used as catalysts to promote hydrosilylation reactions.

[0059] On the other hand, as catalysts for hydrosilylation reactions, so-called high-energy ray-activated catalysts or photoactivated catalysts such as (methylcyclopentadienyl)trimethylplatinum(IV) complex and bis(2,4-pentanedione)platinum(II) complex can be used. By using such catalysts for hydrosilylation reactions, the overall composition can sometimes achieve the following characteristics: it can be cured even at low temperatures when triggered by high-energy ray irradiation, exhibits excellent storage stability, and the reaction is easy to control, thus resulting in excellent workability. In this case, from the perspective of catalytic activation efficiency, ultraviolet light is preferred as the high-energy ray, and from the viewpoint of industrial application, ultraviolet light in the wavelength range of 280–380 nm is preferred. Furthermore, the irradiation dose varies depending on the type of high-energy ray-activated catalyst, but in the case of ultraviolet light, the cumulative irradiation dose at a wavelength of 365 nm is preferably 100 mJ / cm². 2 ~100J / cm 2 Within the range.

[0060] The amount of catalyst added for the hydrosilylation reaction is only the amount of catalyst. More specifically, relative to the whole composition, it is an amount of metal atoms in the range of 0.01 to 500 ppm by mass, an amount in the range of 0.01 to 100 ppm, or an amount in the range of 0.01 to 50 ppm.

[0061] [(B) Thermally conductive filler]

[0062] Component (B) is one or more thermally conductive fillers used to impart thermal conductivity to the composition and the thermally conductive component formed by curing the composition. As such a component (B), it is preferably selected from at least one powder and / or fiber composed of pure metals, alloys, metal oxides, metal hydroxides, metal nitrides, metal carbides, metal silicides, carbon, soft magnetic alloys, and ferrite, preferably metal-based powders, metal oxide-based powders, metal nitride-based powders, or carbon powders. The shape of component (B) is not particularly limited, and examples include spherical, needle-shaped, disc-shaped, rod-shaped, and amorphous shapes, with spherical and amorphous shapes being preferred. Furthermore, the average particle size of component (B) is not particularly limited, but is preferably in the range of 0.01 to 500 μm, and more preferably in the range of 0.01 to 300 μm.

[0063] As component (B), silver powder, aluminum powder, alumina powder, zinc oxide powder, aluminum nitride powder, boron nitride powder, or graphite are preferred. Furthermore, where electrical insulation is required in this composition, metal oxide powders or metal nitride powders are preferred, and alumina powder, zinc oxide powder, boron nitride powder, or aluminum nitride powder are particularly preferred.

[0064] The combination of component (B) is not particularly limited. As an example, it can be (b1-1) plate-shaped boron nitride powder with an average particle size of 0.1 to 150 μm, (b1-2) boron nitride powder shaped into granules or spheres with an average particle size of 0.1 to 500 μm, (b1-3) spherical melt-solidified and / or fragmented alumina powder with an average particle size of 0.01 to 150 μm, or (b1-4) amorphous or spherical aluminum nitride powder with an average particle size of 0.1 to 150 μm, or (b1-5) spherical and / or fragmented graphite with an average particle size of 0.01 to 50 μm, or a mixture of two or more of these components. As a preferred example of component (B), it is a mixture of two or more spherical and fragmented alumina powders with an average particle size of 0.01 to 50 μm. In particular, as exemplified by the embodiments of this application, by combining large-particle-size alumina powder with small-particle-size alumina powder in a ratio according to the distribution curve of dense filling theory, the filling efficiency can be improved, and the viscosity can be reduced and the thermal conductivity increased.

[0065] Furthermore, from the viewpoint of improving the thermal conductivity of the cured product without compromising the rubber properties and extrusion operability of the thermally conductive composition of the present invention, as component (B), it is preferable to substantially not contain thermally conductive fillers with an average particle size of less than 2.0 μm, particularly aluminum nitride powder (hereinafter sometimes referred to as "coarse particles"). Here, "substantially not contain" means that the content of thermally conductive fillers with an average particle size of less than 2.0 μm, particularly aluminum nitride powder, in the total thermally conductive filler is less than 0.5% by volume, more preferably less than 0.1% by volume, and particularly preferably less than the detection limit (=0.0% by volume). On the other hand, when more than 0.5% by mass of aluminum nitride powder with an average particle size of less than 2.0 μm is mixed into the thermally conductive filler, the technical effects of the present invention cannot always be fully achieved.

[0066] Furthermore, from the viewpoint of the rubber properties of the thermally conductive composition of the present invention and its good operability during extrusion, it can be used in combination with...

[0067] (b2-1) A thermally conductive filler with an average particle size in the range of 0.1 to 1.0 μm, selected from at least one of zinc oxide powder and alumina powder;

[0068] (b2-2) A thermally conductive filler with an average particle size in the range of 2.0 to 29 μm, selected from at least one of amorphous, spherical and polyhedral aluminum nitride powder and aluminum oxide powder;

[0069] (b2-3) Aluminum nitride powders with an average particle size of 30 μm or larger, selected from amorphous, spherical, and polyhedral forms; and

[0070] (b2-4) Spherical aluminum nitride powder with an average particle size greater than 50 μm

[0071] Furthermore, preferred thermally conductive fillers are described below. By selecting these thermally conductive fillers as component (B) and using them in combination with component (C), the technical problems of the present invention can sometimes be particularly suitably solved.

[0072] Component (b2-1) is a thermally conductive filler selected from at least one of zinc oxide powder and alumina powder, with an average particle size ranging from 0.1 to 1.0 μm. Its shape is not particularly limited, and examples include spherical, needle-like, disc-like, rod-like, and amorphous shapes, with spherical and amorphous shapes being preferred. It should be noted that spherical shapes include polyhedral spherical shapes. Furthermore, the average particle size of component (A) is preferably in the range of 0.10 to 0.75 μm, but may also be in the range of 0.10 to 0.60 μm.

[0073] Component (b2-1) is a thermally conductive filler with the smallest average particle size among the thermally conductive fillers of the present invention, added for the purpose of fine filling. By using the above component in a certain amount range and in combination with aluminum nitride powder, etc., as described later, the thermal conductivity of the cured product can be improved without impairing the rubber properties and the workability during extrusion.

[0074] Component (b2-2) is aluminum nitride powder and aluminum oxide powder selected from amorphous, spherical, and polyhedral forms, with an average particle size ranging from 2.0 to 29 μm. The shape of component (b2-2) is preferably amorphous, excluding spherical and polyhedral spherical forms. In other words, spherical or polyhedral spherical components are explicitly excluded from the range of components (b2-2). Furthermore, in this invention, amorphous means that the particles do not have a definite shape, have multiple corners or protrusions, and are particularly distinguishable from symmetrical spherical or polyhedral spherical forms. Further, spherical refers to particles with few corners and smooth, spherical-like surfaces, but because they still have corners or protrusions, they can be clearly distinguished from the aforementioned symmetrical spherical or polyhedral spherical forms. Additionally, polyhedral refers to spherical surfaces without rounded corners, and is therefore clearly distinguishable from symmetrical spherical or polyhedral spherical forms. Spherical objects are difficult to contact due to the lack of corners and have poor thermal conductivity, and are therefore not preferred. In this invention, the most preferred component (b2-2) is amorphous aluminum nitride powder and aluminum oxide powder with an average particle size in the range of 2.0 to 29 μm. Furthermore, the average particle size of component (b2-2) is preferably in the range of 2.1 to 25 μm, but can also be in the range of 2.4 to 15.0 μm. When the type of component (b2-2) is different, or when the particle size is smaller than the above lower limit, the operability during extrusion is impaired, or a paste-like composition cannot be obtained at all, and it is sometimes difficult to extrude from a cassette or dispensing machine.

[0075] Component (b2-3) is aluminum nitride powder with an average particle size of 30 μm or more, selected from amorphous, spherical, and polyhedral forms. In particular, by using it in combination with components (b2-1) and (b2-2) in a specific range, the technical effects of this invention are achieved, especially by avoiding anisotropy and achieving a very high thermal conductivity. It should be noted that component (b2-2) is defined by its upper limit of average particle size.

[0076] The shape of component (b2-3) is preferably amorphous, excluding spherical and polyhedral spherical shapes. It should be noted that "amorphous," "quasi-spherical," and "polyhedral" are the same as those described in component (B) above, and components (b2-3) having these shapes are clearly distinguishable in shape from symmetrical spherical or polyhedral spherical particles. In this invention, the most preferred component (b2-3) is amorphous aluminum nitride powder with an average particle size in the range of 30 μm or more. Furthermore, in this invention, as a large-particle-size and spherical aluminum nitride powder, component (b2-3) described later can be used in conjunction, and is preferred.

[0077] The average particle size of component (b2-3) is 30 μm or more, and can be in the range of 30–300 μm or 30–180 μm. Furthermore, as described above, component (b2-3) preferably does not contain aluminum nitride powder with an average particle size of less than 2.0 μm, and most preferably, the amount of such particles in the component (b2-3) is 1% by volume or less, and more preferably 0% by volume or less (with one significant figure). This is because if the content of low-particle-size aluminum nitride powder is high, even when using a specific amount of component (b2-3), the operability during extrusion may be impaired due to the influence of the low-particle-size aluminum nitride powder, or a paste-like composition may not be obtained, making extrusion itself difficult.

[0078] Component (b2-4) is spherical aluminum nitride powder with an average particle size greater than 50 μm. In this invention, its composition is arbitrary, but it is particularly improved by being used in combination with components (b2-1), (b2-2), and (b2-3) in a certain range of amounts. This further enhances the technical effect of the invention, especially by avoiding anisotropy and achieving very high thermal conductivity. It should be noted that component (b2-2) is classified according to its upper limit of average particle size, while component (b2-3) is classified according to its shape.

[0079] The average particle size of component (b2-4) is greater than 50 μm, and can be in the range of 51–300 μm or 51–180 μm. Furthermore, component (b2-4) preferably does not contain aluminum nitride powder with an average particle size of less than 2.0 μm, and most preferably, the amount of such particles in the component (b2-4) is 1% by volume or less, and more preferably 0% by volume (with one significant figure). The reasoning is the same as that described for component (b2-3).

[0080] [(B) Quantity of thermally conductive filler]

[0081] The composition of the present invention has a very high thermal conductivity of 9.0 W / mK or higher, and can form a cured product with practically sufficient softness and stress relief properties and a thermally conductive component formed therefrom. Furthermore, when filled into a cartridge or the like, since it is a paste, in order to achieve the characteristic of excellent operating efficiency during extrusion, it is necessary to set the range of the above-mentioned components in a specific range.

[0082] Specifically, in this invention, to achieve high thermal conductivity, the content of the thermally conductive filler as component (B) is in the range of 60 to 95% by volume relative to the total solid components in the composition, preferably in the range of 65 to 95% by volume, 70 to 93% by volume, or 75 to 92% by volume. If the content of the thermally conductive filler is less than the lower limit mentioned above, the thermal conductivity of the resulting composition tends to decrease, and sometimes the high thermal conductivity, especially the high thermal conductivity of 9.0 W / mK or higher, which is the objective of this invention, cannot be achieved. On the other hand, if the content is greater than the upper limit of the above range, even when component (C) is incorporated or used for surface treatment of fillers, the viscosity of the resulting composition will increase significantly, or the initial cured product will become significantly harder, and sometimes its workability, stress relief characteristics on the substrate, and adhesion will also decrease.

[0083] It should be noted that, relative to 100 parts by weight of component (A), the combined amount of the thermally conductive filler used as component (B) is more preferably in the range of 600 to 6000 parts by weight, and particularly preferably in the range of 800 to 4000 parts by weight. When the amount of thermally conductive filler satisfies the above-mentioned volume percentage range, and also satisfies the above-mentioned range relative to the amount of component (A), the technical problem of the present invention can be particularly appropriately solved.

[0084] Preferably, the content of the above-mentioned components (b2-3) is in the range of 1.0 to 20.0 vol% relative to the total solid components in the composition, more preferably in the range of 2.0 to 20.0 vol% or 3.0 to 19.0 vol%.

[0085] Component (D) is an optional component of the present invention, and therefore its content is in the range of 0.0 to 30.0 vol% relative to the total solid components in the composition, preferably in the range of 3.0 to 30.0 vol% or 5.0 to 30.0 vol%.

[0086] Furthermore, relative to the solid components in the composition as a whole, the content of amorphous aluminum nitride powder selected from components (b2-2) and (b2-3) is preferably 50% by mass or less.

[0087] Furthermore, the content of the thermally conductive filler, which is aluminum nitride powder, is particularly preferably 60% by mass or less, relative to the total solid components in the composition. Aluminum nitride powder is prone to internal cracking due to ammonia gas generated from hydrolysis, and this tendency becomes more pronounced as the filler content increases; therefore, minimizing the amount used is useful in addressing this problem.

[0088] It should be noted that for other thermally conductive fillers, in order to improve their filling efficiency, for example by combining large-particle-size powder with small-particle-size powder in a ratio according to the distribution curve of dense filling theory, the filling efficiency can be improved, and sometimes low viscosity and high thermal conductivity can be achieved.

[0089] [Other inorganic fillers]

[0090] As an optional component, the composition of the present invention may, for example, be formulated with inorganic fillers (also referred to as "inorganic filler materials") such as fumed silica, wet silica, pulverized quartz, titanium dioxide, magnesium carbonate, zinc oxide, iron oxide, diatomaceous earth, and carbon black, and obtained by hydrophobically treating the surface of these inorganic fillers using the following component (E) and / or other organosilicon compounds (silazanes, etc.). However, from the viewpoint of the technical effects of the present invention, and particularly from the viewpoint of balancing high thermal conductivity and the softness and stress relief properties of the cured product, from the extrusion operability of the cartridge, etc., and the adhesion to the substrate, it may be a composition that substantially does not contain fillers other than the thermally conductive filler as component (B). On the other hand, for the purpose of improving (strengthening) mechanical strength, adjusting viscosity, and other functions, the above-described fillers may be used within a range that does not impair the technical effects of the present invention, and may be included in one of the preferred embodiments of the present invention.

[0091] [(C) Macromolecular monomer type treatment agent with specific degree of polymerization]

[0092] Component (C) is one of the characteristic components of the composition of the present invention. By using this component, the thermally conductive composition is improved in terms of extrusion operability and ejection properties such as those of cartridges. In addition to excellent filling properties for small-capacity packaging, it also provides a composition with excellent operating efficiency during coating. Furthermore, even when the cured product is heated and aged at high temperatures, the change in hardness of the cured product is small, and it can maintain flexibility and stress relief properties. Therefore, it can maintain good heat dissipation properties for heat dissipation parts for a long time. In particular, component (C) is a component with critical significance in its degree of polymerization a of siloxane.

[0093] Specifically, component (C) is of general formula (1):

[0094] [Chemical Formula 2]

[0095]

[0096] (where R) 1 R is an independent, unsubstituted or substituted monovalent hydrocarbon group without a carbon-carbon double bond. 2 Organopolysiloxanes with a viscosity of 10 to less than 10,000 mPa·s at 25°C, defined as (independently hydrogen atoms, alkyl, alkoxyalkyl, or acyl groups, where a is a number from 40 to 90 and b is an integer from 1 to 3).

[0097] In general formula (1), R 1 Independently, it is a monovalent hydrocarbon group without a carbon-carbon double bond, whether unsubstituted or substituted. Examples include straight-chain alkyl, branched alkyl, cyclic alkyl, aryl, aralkyl, and haloalkyl. Industrially, R... 1 Methyl or phenyl is preferred, and from the viewpoint of heat resistance, methyl is preferred.

[0098] R 2 Independently, it can be a hydrogen atom, alkyl, alkoxyalkyl, alkenyl, or acyl group. From a surface treatment point of view, R 2 Alkyl groups are preferred, and methyl or ethyl groups are particularly preferred.

[0099] In general formula (1), when the degree of polymerization of the siloxane, represented by 'a', is within a specific range, the extrusion workability, heat aging properties of the cured product, and thermal conductivity of the composition can be further improved. When the value of 'a' is not within a specific range (e.g., when 'a' is 30 or 100), even when using the organopolysiloxane shown in general formula (1), the extrusion workability and heat aging properties of the cured product of the composition of the present invention sometimes cannot be sufficiently improved. Specifically, 'a' in general formula (1) needs to be a number in the range of 40 to 90, and is particularly preferably a number in the range of 40 to 90, 45 to 90, 50 to 90, or 50 to 80. Furthermore, as OR 2 The number of terminal hydrolyzable groups, b, shown is an integer from 1 to 3, preferably 2 or 3. As a component (C) of the present invention, b is preferably 3, having a trialkoxysilyloxy group at a single end of the molecular chain, R 1 It is a polydimethylsiloxane with methyl groups.

[0100] Component (C) is a surface treatment agent that functions as a thermally conductive filler or other inorganic filler. It can coexist with these components in the composition. It is preferred to use component (C) to surface treat the inorganic filler that is component (B). This is particularly preferred for further improving the uniform dispersion of these components and the processability of the resulting composition, especially the extrusion processability of the composition, the heat aging properties of the cured product, and the thermal conductivity.

[0101] [(C'), (C'') other surface treatment agents]

[0102] In addition to component (C), the present invention may also contain ingredients selected from...

[0103] (C') General formula (2):

[0104] R alk R 3 2SiO(R 3 2SiO) c R 3 2Si-R 4 -SiR 3 (3-d) (OR 5 ) d

[0105] (where R) alk It is an alkenyl group, R 3 R is an independent, unsubstituted or substituted monovalent hydrocarbon group without a carbon-carbon double bond. 4 R is an oxygen atom or a divalent hydrocarbon group. 5 Independently comprising a hydrogen atom, alkyl, alkoxyalkyl, or acyl group, where c is an integer from 1 to 250 and d is an integer from 1 to 3. Siloxane compounds with an alkenyl group and a hydrolyzable silane group at the end of their molecular chains, as shown in the figure, having a viscosity at 25°C in the range of 10 to 10000 mPa·s; and

[0106] (C'') Alkoxysilanes or their hydrolytic condensates having 6 or more carbon atoms in their molecule

[0107] One or more surface treatment agents.

[0108] For component (C'), R in general formula (2) alk The alkenyl group can be exemplified by vinyl, allyl, hexenyl, and other alkenyl groups with 2 to 10 carbon atoms. Component (C') has an alkenyl group at a single end of the molecular chain, and therefore, in addition to its effect as a surface treatment agent and thermally conductive filler of component (B), it can sometimes improve curing and adhesion properties when used in combination with other crosslinking agents.

[0109] In the formula, R 3 Independently, it is an unsubstituted or substituted monovalent hydrocarbon group without a carbon-carbon double bond, including straight-chain alkyl, branched alkyl, cyclic alkyl, alkenyl, aryl, aralkyl, and haloalkyl groups. From an industrial point of view, it is methyl or phenyl, with methyl being preferred from a heat resistance point of view. R 4 It is an oxygen atom or a divalent hydrocarbon group. As R... 4 Divalent hydrocarbon groups can be exemplified by alkylene groups such as methylene; and alkylene oxides such as ethyleneoxide and ethyleneoxide propylene oxide. On the other hand, R... 4 It can be an oxygen atom, and is preferred.

[0110] In the formula, R 5Independently, it is a hydrogen atom, alkyl, alkoxyalkyl, or acyl group, preferably alkyl, and from the viewpoint of surface treatment, particularly preferably methyl or ethyl. The component (C') is determined by Si(OR). 5 The single-terminal structure shown in the figure has hydrolyzable silanes within the molecule, thus providing excellent surface treatment results when used in conjunction with component (C).

[0111] In the formula, c is the degree of polymerization (excluding the terminal) of the diorganosiloxane unit of component (C'), which is an integer from 1 to 250, preferably an integer from 1 to 100, and particularly preferably an integer from 1 to 50. In the formula, d is an integer from 1 to 3, preferably 3. When d is 3, the single terminal of component (C') is particularly preferably trimethoxysilyl (-Si(OMe)3).

[0112] The amount of component (C) and component (C') (or the total amount when both are used together) is not particularly limited as long as it is sufficient for the surface treatment of the filler. As an example, the amount of component (B) in the composition is in the range of 0.005 parts to 100 parts by weight relative to 100 parts by weight, preferably 0.05 parts to 100 parts by weight, and more preferably 0.5 parts to 50 parts by weight.

[0113] Component (C'') is an alkoxysilane or its hydrolytic condensate having an alkyl group having 6 or more carbon atoms in the molecule, and is used as a surface treatment agent for component (B), and is particularly preferred to be used in conjunction with component (C).

[0114] Component (C''), like component (C) or component (C'), is a surface treatment agent that functions as a thermally conductive filler in the composition, improving its dosage, overall viscosity and flowability, and adhesive properties. Such alkoxysilanes preferably have an alkyl group of C6 or more.

[0115] Specific examples of alkyl groups having 6 or more carbon atoms include hexyl, octyl, dodecyl, tetradecyl, hexadecyl, octadecyl, etc.; aralkyl groups such as benzyl and phenylethyl, etc., with alkyl groups having 6 to 20 carbon atoms being particularly preferred.

[0116] Component (C'') is preferably derived from the following structural formula

[0117] Y n Si(OR) 4-n

[0118] (In the formula, Y is an alkyl group with 6 to 18 carbon atoms, R is an alkyl group with 1 to 5 carbon atoms, and n is a number from 1 to 3.)

[0119] The alkoxysilanes shown, as OR groups, can be exemplified by methoxy, ethoxy, propoxy, butoxy, etc., with methoxy and ethoxy being particularly preferred. It should be noted that n is 1, 2, or 3, with 1 being particularly preferred.

[0120] Such a component (C'') can specifically be exemplified by C6H. 13 Si(OCH3)3, C8H 17 Si(OC2H5)3, C 10 H 21 Si(OCH3)3, C 11 H 23 Si(OCH3)3, C 12 H 25 Si(OCH3)3, C 14 H 29 Si(OC2H5)3, etc., with decyltrimethoxysilane being the most preferred.

[0121] There is no particular limitation on the amount of component (C'') as long as it is sufficient for the surface treatment of the filler. As an example, it is in the range of 0.005 to 20 parts by mass relative to 100 parts by mass of component (A) in the whole composition, preferably 0.05 to 10 parts by mass, and more preferably 0.5 to 7.5 parts by mass.

[0122] [(B) Surface treatment of thermally conductive fillers and other inorganic fillers]

[0123] In this invention, (B) the thermally conductive filler and any inorganic filler used as needed (hereinafter, these components are collectively referred to as "fillers") are preferably surface-treated using at least a portion of the aforementioned component (C), and more preferably using one or more selected from components (C') and (C''). Furthermore, treatment based on various surface treatment agents known as coupling agents may also be used together with these components as fillers. In addition to components (C), (C'), and (C''), examples of surface treatment agents for treating the fillers of this invention include surfactants, other silane coupling agents, aluminum-based coupling agents, and silicone-based surface treatment agents.

[0124] There are no particular limitations on the surface treatment methods for fillers based on these components; direct treatment of fillers, integral blending, dry concentration, etc., can be used. In this invention, from the viewpoint of improving the overall filling properties of the composition and the thermal conductivity, rubber properties, and adhesive strength of the cured product, the following heated surface treatment method is most preferably exemplified: pre-mixing a portion or all of the following component (A) with surface treatment agents such as component (C), sequentially mixing the filler into the mixture, homogenizing, and then heating (basic heating). In this surface treatment method, the mixture can be heated and stirred at 100–200°C under reduced pressure. The temperature conditions and stirring time can be designed according to the amount of sample, preferably in the range of 120–180°C and 0.25–10 hours. It should be noted that the surface treatment process for the filler is arbitrary, but from the viewpoint of improving the extrusion operability and thermal conductivity of this composition, it can also be a step-by-step process including surface treatment of at least a portion of the filler using component (C), optionally a further component (C'), and then surface treatment of the filler using component (C''). By using a surface treatment agent containing component (C) of the present invention, the extrusion operability of the composition can be improved in particular.

[0125] There are no particular limitations on the apparatus used for the above mixing, and examples include single-shaft or twin-shaft continuous mixers, two-roll mixers, Ross mixers, Hobart mixers, toothed mixers, planetary mixers, kneaders, Henschel mixers, etc.

[0126] [(F) Heat resistance enhancer]

[0127] In addition to the above-described components, the compositions of the present invention may optionally contain a heat-resistant agent. The heat-resistant agent can be formulated alone, and the technical effects of the compositions and their cured products can sometimes be further improved by use in combination with the (G) fatty acid compounds described below. The amount of the heat-resistant agent can be in the range of 0.01 to 5.0% by mass of the total composition (solid components), or in the range of 0.05 to 2.0% by mass or 0.07 to 0.5% by mass.

[0128] Examples of heat-resistant agents include metal oxides such as iron oxide, titanium oxide, cerium oxide, magnesium oxide, and zinc oxide; metal hydroxides such as cerium hydroxide; phthalocyanine compounds; cerium silanol salts; cerium fatty acid salts; reaction products of organopolysiloxanes and cerium carboxylates; and carbon black. Phthalocyanine compounds are particularly preferred (F1). For example, additives selected from the group consisting of metal-free phthalocyanine compounds and metal-containing phthalocyanine compounds, as disclosed in Japanese Patent Publication No. 2014-503680, are preferred. Among metal-containing phthalocyanine compounds, copper phthalocyanine compounds are particularly preferred. One example of a most preferred but not limited heat-resistant agent is 29H,31H-phthalocyanate (2-)-N29,N30,N31,N32 copper. Such phthalocyanine compounds are commercially available, such as Stan-tone (trademark) 40SP03 from PolyOne Corporation (Avon Lake, Ohio, USA). Similarly, by using carbon black (F2) as a heat resistance enhancer in a range of 0.1 to 5% by mass relative to the total composition, preferably 0.2 to 2% by mass, the heat aging resistance above 180°C and the high-temperature heat resistance can be significantly improved.

[0129] [(G) fatty acid compounds]

[0130] In the case of a curable composition of the present invention, in addition to the above-mentioned components, at least one fatty acid compound selected from fatty acid esters and fatty acid metal salts may be optionally included. This component is used to suppress the change in hardness of the present composition and the cured product formed by curing the present composition as an organosilicon-based thermally conductive component during heat aging. In particular, when the amount of the above-mentioned thermally conductive filler is within the above-mentioned range, in addition to the use of component (C), the change in hardness of the cured product during heat aging can be further suppressed by using component (G). The cured product will not harden rapidly during heat aging, and its stress relief, softness, and substrate adhesion will not be impaired. By using component (G) in the hydrogenated silanization curing reactive composition, and preferably using it as a heat-resistant imparting agent of the above-mentioned component (F), the resulting cured product has high thermal conductivity and can maintain its initial hardness and rubber properties, achieving good stress relief, softness, and substrate adhesion.

[0131] Specifically, component (G) is selected from at least one of fatty acids, fatty acid esters, and metal salts of fatty acids, and examples include fatty acids such as hexanoic acid, octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, lauric acid, myristic acid, palmitic acid, stearic acid, benzyl acid, and oleic acid; fatty acid esters as alkyl esters; alkali metal salts of fatty acids such as sodium, lithium, and potassium; and alkaline earth metal salts of fatty acids such as calcium. Preferably, component (G) is selected from at least one of saturated fatty acids and metal salts of saturated fatty acids, and particularly preferably (G1) is selected from at least one of stearic acid, alkali metal salts of stearic acid, and alkaline earth metal salts of stearic acid.

[0132] As a prerequisite for use with component (C), the mechanism by which the combined system of component (G) and optional component (F) suppresses changes in the hardness of the cured product is not clearly defined, but it is speculated that fatty acid compounds such as fatty acid salts (soaps), fatty acid esters, etc., exist in limited amounts within the heat-resistant silicone cured product matrix in the presence of component (C) and optional component (F), thereby forming a water-resistant and lubricating film or local structure composed of these fatty acid compounds on or near the surface of the thermally conductive filler particles. This makes the particle surface chemically inactive or inactive at high temperatures and effectively prevents the aggregation between the surfaces of the thermally conductive filler and the formation of coarse particles. However, component (G) exerts its technical effect even if it is not used as a surface treatment agent for the thermally conductive filler, but is simply mixed uniformly with other components. Therefore, in this invention, there is no limitation on the timing of adding component (G) to the composition.

[0133] The amount of component (G) is preferably in the range of 0.05 to 2.0 parts by mass relative to 100 parts by mass of the thermally conductive filler (B) described above (total amount when composed of multiple components). It should be noted that if the amount of component (G) is less than the lower limit mentioned above, the improvement in the hardness change of the cured product caused by its use with component (C) may sometimes become insufficient. On the other hand, if the amount of component (G) is greater than the upper limit mentioned above, similarly, the improvement effect in suppressing the hardness change of the cured product may sometimes become insufficient.

[0134] [(H) Hydrosilylation reaction inhibitors, adhesion promoters, organic solvents and other additives]

[0135] The compositions of the present invention require components (A) to (C). When component (A) includes a curing reactive component (A2), it is preferable to further include components (D) and (E). More preferably, it may optionally include one or more components selected from components (C'), (C''), (F), and (G). It is particularly preferable to use components (C''), (F), and (G) together. Other components may also be included. Especially when the composition has curable properties, it is particularly preferable to use a hydrosilylation inhibitor.

[0136] [Inhibitors of hydrosilylation reaction]

[0137] When the composition of the present invention has curable properties, from the viewpoint of its operability, it is preferable to further include a hydrosilylation reaction inhibitor. The hydrosilylation reaction inhibitor is a component used to inhibit the hydrosilylation reaction of the thermally conductive organopolysiloxane composition of the present invention. Specifically, examples include, for example, acetylene-based, amine-based, carboxylic acid ester-based, and phosphite-based reaction inhibitors such as acetylenol. The amount of reaction inhibitor added is typically 0.001 to 5% by mass of the total thermally conductive organopolysiloxane composition. In particular, for the purpose of improving the workability of this composition, acetylene compounds such as 3-methyl-1-butyn-3-ol, 3,5-dimethyl-1-hexyn-3-ol, and 3-phenyl-1-butyn-3-ol (=phenylbutynol) may be used without particular restriction; enynyne compounds such as 3-methyl-3-penten-1-yne and 3,5-dimethyl-3-hexen-1-yne; cycloalkenylsiloxanes such as 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane and 1,3,5,7-tetramethyl-1,3,5,7-tetrahexenylcyclotetrasiloxane; methyltris(1,1-dimethyl-2-propynoxy)silane; and triazole compounds such as benzotriazole.

[0138] [Adhesion-enhancing agent]

[0139] In the compositions of the present invention, an adhesive-improving agent may be formulated to improve the adhesive strength and permanent adhesion to the substrate of the cured product, etc. The adhesive-improving agent that can be used in the present invention may be selected from one or more of the following adhesive-improving agents: a reaction mixture of an amino-containing organoalkoxysilane and an epoxy-containing organoalkoxysilane (including carbasilyl heterocyclic derivatives and silicone heterocyclic propylene derivatives having specific structures), an organic compound having two or more alkoxysilyl groups in its molecule, represented by a disilane compound (e.g., 1,6-bis(trimethoxysilyl)hexane), an epoxy-containing silane, or a partially hydrolyzed condensate thereof; two or more adhesive-improving agents selected from these may be used in combination, and preferably.

[0140] The adhesive agent preferably comprises, in a mass ratio of 5:95 to 95:5, more preferably 50:50 to 95:5, and even more preferably 60:40 to 90:30.

[0141] (L-1) From the general formula:

[0142] R a n Si(OR b ) 4-n

[0143] (where R)a R is a monovalent organic group containing an epoxy group. b It consists of alkyl groups or hydrogen atoms with 1 to 6 carbon atoms. (n is a number in the range of 1 to 3)

[0144] The epoxy-containing silane or its partially hydrolyzed condensation polymer shown; and

[0145] (L-2) An organic compound having at least two alkoxysilyl groups in a molecule and containing bonds other than silicon-oxygen bonds between these silyl groups.

[0146] It should be noted that while these components can improve the initial adhesion of organopolysiloxane cured products even when used individually, when combined in the mass ratios described above, they can sometimes significantly improve the initial adhesion, adhesion durability, and adhesion strength (permanent adhesion) of organopolysiloxane cured products.

[0147] Examples of the above-mentioned components (L-1) include 3-glycidyl etheroxypropyltrimethoxysilane, 3-glycidyl etheroxypropylmethyldimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and 2-(3,4-epoxycyclohexyl)ethylmethyldimethoxysilane.

[0148] Examples of the above-mentioned components (L-2) include disilane hydrocarbons such as 1,6-bis(trimethoxysilyl)hexane, 1,6-bis(triethoxysilyl)hexane, 1,4-bis(trimethoxysilyl)hexane, 1,5-bis(trimethoxysilyl)hexane, 2,5-bis(trimethoxysilyl)hexane, 1-methyldimethoxysilyl-6-trimethoxysilylhexane, 1-phenyldiethoxysilyl-6-triethoxysilylhexane, and 1,6-bis(methyldimethoxysilyl)hexane.

[0149] As an adhesive agent other than the aforementioned components (L-1) and (L-2), it may further be used in the reaction mixture of an amino-containing organoalkoxysilane and an epoxy-containing organoalkoxysilane disclosed in Japanese Patent Publication No. 52-8854 and Japanese Patent Application Publication No. 10-195085 (including carbasil heterocyclic derivatives and silicone heterocyclic propylene derivatives with specific structures).

[0150] [Organic solvents and other additives]

[0151] In addition to the components described above, the thermally conductive composition of the present invention may be formulated with any components without prejudice to the purpose of the present invention. Examples of such arbitrary components include, for instance, cold-resistance agents, flame-retardant agents, pigments, dyes, etc. Furthermore, the thermally conductive composition of the present invention may, as desired, contain one or more antistatic agents composed of known surfactants, dielectric fillers, conductive fillers, release agents, thixotropic agents, and antifungal agents, etc. Additionally, organic solvents may be added as desired.

[0152] [Preparation method and dosage form of the composition]

[0153] The thermally conductive composition of the present invention can be prepared by mixing the above-described components. Examples of mixing devices include those similar to those exemplified in the surface treatment of the filler. Furthermore, as described above, component (G) can be added after the surface treatment / basic heating of the filler, or it can be added together with the surface treatment agent of the filler; regardless of when it is added, the technical effects of the present invention can be achieved.

[0154] More specifically, the compositions of the present invention are preferably manufactured by any of the following manufacturing methods (mixing processes):

[0155] i) A manufacturing method comprising the following steps: after a step of heating and mixing the mixture of the above-mentioned component (A), the filler containing component (B) and the surface treatment agent containing component (C), an optional component (G) and other components are mixed.

[0156] ii) A manufacturing method comprising the following steps: after a step of heating and mixing the mixture of the above-mentioned component (A), the filler containing the filler component (B), optional component (G) and component (C), a step of mixing other components.

[0157] It should be noted that the heating conditions are the same as the basic heating conditions described previously in the section on the surface treatment of fillers, and mixing is preferably carried out in a substantially uniform manner.

[0158] The thermally conductive composition of the present invention can be a single-component composition, optionally a composition containing the above-mentioned hydrosilylation reaction inhibitor and other components, or a multi-component composition consisting of two or more separately stored compositions. In the case of a multi-component composition, it is necessary not to simultaneously contain the above-mentioned components (A), (D), and (E) containing component (A2). This is because if these components (main agent, crosslinking agent, and catalyst) are prepared simultaneously, the crosslinking reaction will automatically begin, and the composition will lose its storage stability in a short time, sometimes failing to achieve the long-term storage stability and workability intended for a multi-component composition. It should be noted that when using the multi-component composition, it is stirred in a common container using mechanical force such as a stirrer, or mixed using a dispensing machine or similar device corresponding to multi-component mixing for coating or application.

[0159] The thermally conductive composition of the present invention has extremely high thermal conductivity, and its cured product exhibits excellent flexibility and stress-relieving properties. It is also easily extruded from cartridges or dispensing machines, exhibiting excellent handling efficiency, filling capacity, and coatability. Therefore, it has the advantage of excellent coating and extrusion operability, particularly for small-scale applications, such as filling small-scale syringes (approximately 10-300 ml). Consequently, this composition is easily filled into small-scale cartridges and syringes and is readily applicable to small-volume packaging production. In particular, the thermally conductive composition of the present invention, by including component (C) as a macromolecular monomer-type treatment agent with a specific degree of siloxane polymerization, improves its extrusion operability, making it especially suitable for small-volume packaging production.

[0160] [Use of non-curing / uncured compositions]

[0161] The thermally conductive composition of the present invention can be applied to a heat dissipation component or a circuit board on which the heat dissipation component is mounted in a non-cured or uncured state to obtain a heat dissipation structure having an uncured heat dissipation component (examples include thermal grease and uncured thermally conductive gap filler material).

[0162] [Curing properties]

[0163] When the thermally conductive composition of the present invention contains at least a portion of a curing reactive component (A2) in component (A), it can be cured by hydrosilylation reaction to form a cured product with excellent thermal conductivity, suppressed hardness change even after heat aging, and excellent softness and stress relief properties. The temperature conditions for curing this hydrosilylation reaction-curable composition are not particularly limited, but are generally in the range of 20°C to 200°C, preferably in the range of 20°C to 150°C, and more preferably in the range of 20°C to 80°C. It can also be cured at high temperature for a short time, or at low temperature such as room temperature for a long time (e.g., several hours to several days), without particular limitation. It should be noted that at least a portion of component (E) can be selected to activate a high-energy ray catalyst or a photo-activated catalyst, thereby achieving curing triggered by high-energy ray irradiation.

[0164] By using the thermally conductive composition of the present invention, the above-described curable thermally conductive composition can be applied to a heat dissipation component or a circuit board on which the heat dissipation component is mounted, and a cured product is formed at a temperature of 20°C to 150°C, preferably below 130°C, for example in the range of 20°C to 125°C, to obtain a heat dissipation structure provided with a heat dissipation component.

[0165] [Thermal conductivity]

[0166] The thermally conductive composition of the present invention can stably and highly fill with a thermally conductive filler, preferably having a thermal conductivity of 9.0 W / mK or higher, and particularly preferably 9.1 W / mK or higher. It should be noted that the thermally conductive composition of the present invention can be designed with compositions and cured products having a thermal conductivity of 9.0 to 15.0 W / mK, and, as needed, a thermal conductivity of 9.1 to 14.0 W / mK, and exhibits excellent workability such as extrusion and dispensing properties in cartridges, etc. Furthermore, this composition can be either non-curable or curable. By including component (C) as a macromolecular monomer-type treatment agent having a specific degree of polymerization of siloxanes, in addition to improving its extrusion workability and thermal conductivity, in the case of curable composition, its heat aging properties at high temperatures are particularly excellent. Furthermore, by using components (F) / (G) (particularly the use of at least one of a phthalocyanine compound as component (F1) and carbon black as component (F2), hardness changes can be further suppressed even after heat aging, enabling the achievement of a thermally conductive cured product with excellent softness and stress relief properties.

[0167] [Applications and Heat Dissipation Structure]

[0168] The thermally conductive composition and its cured product of the present invention are useful as heat transfer materials (thermally conductive components) sandwiched at the interface between the thermal boundary surface of a heat-generating component and a heat dissipation component such as a heat sink or circuit board for cooling heat-generating components based on thermal conduction, and can form a heat dissipation structure having the composition and its cured product. Here, the type, size, and structure of the heat-generating component are not particularly limited, but the thermally conductive composition of the present invention or the cured product thereof not only has high thermal conductivity, but also excellent initial adhesion and adhesive strength to the component, and even after long-term hardness changes after heat aging, it suppresses the hardness changes and maintains flexibility and stress relief characteristics. Therefore, it is not easy to peel off from the heat-generating component due to vibration, etc., and it has high adhesion and conformability, and excellent industrial productivity. Therefore, it is preferably used in heat dissipation structures for automotive parts, electrical / electronic parts, or electrical / electronic equipment including cell-type secondary batteries.

[0169] There are no particular limitations on the structure of such a heat dissipation structure. Examples include a heat dissipation structure formed by providing a heat dissipation member on a heat dissipation component or a circuit board on which the heat dissipation component is mounted, using the aforementioned thermally conductive composition or its cured form. For example, such a structure can be illustrated by an electronic component, which serves as a heat dissipation member, mounted on a circuit board, and dissipating the heat generated by the electronic component through a thin film layer of the thermally conductive composition or its cured form via the heat dissipation member. These components, as a feature of the present invention, exhibit minimal hardness change after heat aging, maintaining the flexibility, stress relief, and excellent fit and conformability of the heat dissipation member. Therefore, they can be appropriately positioned not only on a horizontal plane but also on an inclined or vertical plane.

[0170] In such a heat dissipation structure, the thickness of the thermally conductive composition or its cured form is not particularly limited and can be in the range of 0.1 mm to 100 mm, which can efficiently transfer the heat generated by electronic components that are filled with the composition or its cured form without gaps to the heat dissipation component.

[0171] There are no particular limitations on electrical / electronic devices incorporating components made from the aforementioned thermally conductive composition. Examples include secondary batteries such as cell-type lithium-ion electrode secondary batteries and battery stack-type fuel cells; electronic circuit boards such as printed circuit boards; IC chips encapsulating optoelectronic semiconductor elements such as diodes (LEDs), organic electroluminescent devices (organic ELs), laser diodes, and LED arrays; CPUs used in electronic devices such as personal computers, digital video discs, mobile phones, and smartphones; and LSI chips such as driver ICs and memory. In particular, in high-performance digital / conversion circuits formed with high integration density, heat removal (heat dissipation) becomes a major factor for the performance and reliability of integrated circuits. Thermally conductive components made using the thermally conductive organopolysiloxane composition of the present invention exhibit excellent heat dissipation and operability even when applied to power semiconductor applications such as engine control, powertrain, and air conditioning control in conveyors. Even when assembled into automotive electronic components such as electronic control units (ECUs) and used in harsh environments, they maintain strong adhesion to the components, achieving excellent heat resistance and thermal conductivity.

[0172] Example

[0173] The present invention is illustrated below with examples, but the invention is not limited to these examples. In the examples and comparative examples shown below, the following compounds or compositions were used as raw materials. It should be noted that the average particle size of the thermally conductive filler is the cumulative average particle size D50 (median diameter) in the particle size distribution based on the volume of laser diffraction scattering method, which is a value determined based on the content (volume%) of coarse particles using the same method.

[0174] [Preparation of the composition and fabrication of thermally conductive organopolysiloxane cured products (evaluation samples)]

[0175] The components were mixed using the method described later to obtain the thermally conductive compositions of the examples and comparative examples (hereinafter, sometimes referred to as "thermally conductive organopolysiloxane compositions"). The thermally conductive organopolysiloxane compositions were filled into a mold with a height of 6 mm, a length of 50 mm, and a width of 30 mm. After curing at 80°C for 30 minutes, the mold was removed to obtain the cured thermally conductive organopolysiloxane. The hardness of the obtained cured thermally conductive organopolysiloxane was determined using the following method.

[0176] [Hardness (E type hardness)]

[0177] For hardness testing, two pieces of thermally conductive organopolysiloxane cured material obtained under the above conditions were overlapped, and the value was measured after 3 seconds using an ASKER TYPE E hardness tester manufactured by ASKER Corporation.

[0178] [Thermal conductivity]

[0179] For the determination of thermal conductivity, two pieces of thermally conductive organopolysiloxane cured material obtained under the above conditions were used, and the measurement was performed using a TPS-500 (hot plate method) manufactured by Kyoto Electronics Industries, Ltd.

[0180] [Changes in hardness and thermal conductivity]

[0181] For the hardness variation, the initial hardness of the thermally conductive organopolysiloxane cured product obtained under the above conditions and the hardness of the same cured product subjected to 100 hours of aging treatment in an oven at 150°C were calculated.

[0182] The change in thermal conductivity was calculated based on the initial thermal conductivity of the cured organopolysiloxane obtained under the above conditions and the thermal conductivity of the cured material after 100 hours of aging treatment in an oven at 150°C. If internal voids are generated due to aging, the thermal conductivity will decrease, which can be interpreted as internal foaming or cracking.

[0183] [Extrusion volume]

[0184] For extrusion volume, the thermally conductive composition was filled into a 30cc EFD syringe (manufactured by Nordson) and the extrusion weight per minute was measured when extruding at an extrusion pressure of 80 psi.

[0185] The composition of the present invention is formed from the following components.

[0186] Ingredient (C):

[0187] C-1: Formula: (CH3)3SiO[(CH3)2SiO] 40 Si(OCH3)3

[0188] C-2: Formula: (CH3)3SiO[(CH3)2SiO] 50 Si(OCH3)3

[0189] C-3: Formula: (CH3)3SiO[(CH3)2SiO] 60 Si(OCH3)3

[0190] C-4: Formula: (CH3)3SiO[(CH3)2SiO] 70 Si(OCH3)3

[0191] C-5: Formula: (CH3)3SiO[(CH3)2SiO] 80 Si(OCH3)3

[0192] C-6: Formula: (CH3)3SiO[(CH3)2SiO] 90 Si(OCH3)3

[0193] Non-C-1: Formula: (CH3)3SiO[(CH3)2SiO] 30 Si(OCH3)3

[0194] Non-C-2: Formula: (CH3)3SiO[(CH3)2SiO] 100 Si(OCH3)3

[0195] Non-C-3: Formula: (CH3)3SiO[(CH3)2SiO] 110 Si(OCH3)3

[0196] The organopolysiloxane shown is a macromolecular monomer-type treatment agent.

[0197] Ingredient (B):

[0198] B-1: Amorphous zinc oxide powder with an average particle size of 0.12 μm

[0199] B-2: Polyhedral spherical α-type alumina powder with an average particle size of 2μm

[0200] B-3: Amorphous aluminum nitride powder with an average particle size of 18.5 μm

[0201] B-4: Amorphous aluminum nitride powder with an average particle size of 100 μm

[0202] B-5: Spherical magnesium oxide powder with an average particle size of 120 μm

[0203] Ingredients (A):

[0204] A-1: Dimethylvinylsiloxy-terminated dimethyl polysiloxane (molecular weight dispersion 1.14, number average molecular weight 3890, Vi content 2.13% by mass)

[0205] Ingredient (D):

[0206] D-1: A methylhydrosiloxane-dimethylsiloxane copolymer with trimethylsiloxy groups at both ends of the molecular chain, averaging 2 groups per molecule and 2 groups per side chain (viscosity 20 mPa·s, Si-H content 0.10% by mass).

[0207] D-2: A methylhydrosiloxane-dimethylsiloxane copolymer with trimethylsiloxy groups at both ends of the molecular chain, averaging 3 groups per molecule and 3 groups per side chain (viscosity 12 mPa·s, Si-H content 0.21% by mass).

[0208] Ingredient (E):

[0209] E-1: A complex of platinum at a concentration of 5200 ppm and 1,3-divinyl-1,1,3,3-tetramethyldisiloxane.

[0210] Component (H):

[0211] H-1: Methyltri-1,1-dimethyl-2-propynoxysilane

[0212] Ingredients (F):

[0213] F-1: 29H,31H-phthalocyanate (2-)-N29,N30,N31,N32 copper

[0214] Other ingredients:

[0215] Ingredient (C''-1): Decyltrimethoxysilane

[0216] Ingredient (G-1): Calcium stearate (made by Fujifilm and Kohsen Pharmaceutical).

[0217] [Example 1]

[0218] Weigh 1.00 parts by mass of component (C-1), 2.31 parts by mass of component (A-1), 0.78 parts by mass of component (D-1), 0.120 parts by mass of component (D-2), 0.20 parts by mass of component (C''-1), and 0.10 parts by mass of component (G-1). Then, sequentially mix 14.28 parts by mass of component (B-1), 28.0 parts by mass of component (B-2), 19.0 parts by mass of component (B-3), 18.5 parts by mass of component (B-4), and 15.5 parts by mass of component (B-5) over 60 minutes. After homogenization, heat and mix at 160°C under reduced pressure for 60 minutes, then cool to room temperature to obtain the mixture.

[0219] In this mixture, 0.001 parts by mass of component (H-1) and 0.053 parts by mass of component (F-1) were uniformly mixed. Then, 0.06 parts by mass of component (E-1) were uniformly mixed to obtain a thermally conductive silicone composition. It should be noted that in the mixing of the various embodiments / comparative examples in this invention, a HIVISMIX (model number) was used as the mixing apparatus, manufactured by TOKUSHU KIKA KOGYO CO.,LTD.

[0220] [Example 2]

[0221] The thermally conductive organosilicon composition was obtained in the same manner as in Example 1, except that 1.00 parts by mass of component (C-1) in Example 1 was replaced with 1.00 parts by mass of component (C-2).

[0222] [Example 3]

[0223] The thermally conductive organosilicon composition was obtained in the same manner as in Example 1, except that 1.00 parts by mass of component (C-1) in Example 1 was replaced with 1.00 parts by mass of component (C-3).

[0224] [Example 4]

[0225] The thermally conductive organosilicon composition was obtained in the same manner as in Example 1, except that 1.00 parts by mass of component (C-1) in Example 1 was replaced with 1.00 parts by mass of component (C-4).

[0226] [Example 5]

[0227] The thermally conductive organosilicon composition was obtained in the same manner as in Example 1, except that 1.00 parts by mass of component (C-1) in Example 1 was replaced with 1.00 parts by mass of component (C-5).

[0228] [Example 6]

[0229] The thermally conductive organosilicon composition was obtained in the same manner as in Example 1, except that 1.00 parts by mass of component (C-1) in Example 1 was replaced with 1.00 parts by mass of component (C-6).

[0230] [Comparative Example 1]

[0231] The thermally conductive organosilicon composition was obtained in the same manner as in Example 1, except that 1.00 parts by mass of component (C-1) in Example 1 was replaced with 1.00 parts by mass of component (non-C-1).

[0232] [Comparative Example 2]

[0233] The thermally conductive organosilicon composition was obtained in the same manner as in Example 1, except that 1.00 parts by mass of component (C-1) in Example 1 was replaced with 1.00 parts by mass of component (non-C-2).

[0234] [Comparative Example 3]

[0235] The thermally conductive organosilicon composition was obtained by replacing 1.00 parts by mass of component (C-1) in Example 1 with 1.00 parts by mass of component (non-C-3), otherwise the same as in Example 1.

[0236] Regarding the thermally conductive organopolysiloxane compositions of Examples 1-6, the composition, extrusion amount, hardness, thermal conductivity, and changes in hardness and thermal conductivity after heat aging of the obtained thermally conductive organopolysiloxane cured products are shown in Table 1.

[0237] Regarding the thermally conductive organopolysiloxane compositions of Comparative Examples 1 to 3, the composition, extrusion amount, hardness, thermal conductivity, and changes in hardness and thermal conductivity after heat aging of the obtained thermally conductive organopolysiloxane cured products are shown in Table 2.

[0238] [Table 1]

[0239]

[0240] [Table 2]

[0241]

[0242] As shown in Table 1, the thermally conductive silicone compositions of Examples 1-6, which use macromolecular monomer-type treatment agents with a degree of polymerization within a specified range as component (C) of the present invention, exhibit thermal conductivity greater than 10 W / m·K and extrusion rates greater than 40 g / min, demonstrating good operability. Furthermore, the hardness change of the cured product after aging at 150°C for 100 hours is less than 20 points, the stress relief properties and flexibility of the cured product are unaffected, the thermal conductivity is positive, and the thermal conductivity (= heat dissipation performance) does not decrease after heat aging.

[0243] On the other hand, as shown in Table 2, the thermally conductive silicone composition of Comparative Example 1, which used a macromolecular monomer-type treatment agent with a degree of polymerization below a specified range to replace component (C) of the present invention, exhibited a thermal conductivity greater than 10 W / m·K and an extrusion rate greater than 40 g / min, demonstrating good operability. However, the hardness change of its cured product after aging at 150°C for 100 hours was greater than 20 points, and the stress relief properties and flexibility of the cured product were impaired. Furthermore, the thermal conductivity was negative, and the thermal conductivity (= heat dissipation performance) decreased after heat aging.

[0244] Furthermore, the thermally conductive silicone compositions of Comparative Examples 2 and 3, which used macromolecular monomer-type treatment agents with a degree of polymerization of more than a specified range to replace component (C) of the present invention, showed a thermal conductivity greater than 10 W / m·K, but the extrusion rate was less than 40 g / min, resulting in significantly poorer extrusion operability compared to the examples.

[0245] [Summarize]

[0246] Based on the results of Examples 1 to 6, the thermally conductive organopolysiloxane compositions using components (A) to (C) of the present invention can achieve a high thermal conductivity of 10 W / m·K or more and good extrusion operability with an extrusion rate of more than 40 g / min. Furthermore, even when the hardened reactants are subjected to high-temperature heating aging at 150°C for 100 hours, the changes in hardness and thermal conductivity are minimal. Therefore, it is expected that even after long-term use at high temperatures, good stress relief characteristics, softness, and thermal conductivity can be maintained, and stable thermal conductivity / heat dissipation performance can be maintained.

[0247] On the other hand, based on the results of Comparative Examples 1 to 3, when a polymeric monomer type treatment agent with a degree of polymerization outside the specified range is used instead of the component (C) of the present invention, sufficient extrusion operability is sometimes not achieved, or the hardness changes greatly during high-temperature heating and aging, and the thermal conductivity decreases. If used at high temperatures for a long time, this becomes a cause of deterioration and cracking, or there is a strong concern that stable thermal conductivity / heat dissipation performance cannot be maintained.

Claims

1. A thermally conductive composition, characterized in that, contain: (A) One or more matrix polymers having a viscosity in the range of 10 to 1,000,000 mPa·s at 25°C. (B) One or more thermally conductive fillers, (C) General formula (1): [Chemical Formula 1] (where R) 1 R is an independent, unsubstituted or substituted monovalent hydrocarbon group without a carbon-carbon double bond. 2 Organopolysiloxanes, which are independently hydrogen atoms, alkyl groups, alkoxyalkyl groups, or acyl groups, where a is a number from 40 to 90 and b is a number from 1 to 3. The content of component (B) is 60 to 95% by volume relative to the total solid components in the composition.

2. The thermally conductive composition according to claim 1, wherein, The component (A) is one or more organopolysiloxanes with a viscosity in the range of 10 to 1,000,000 mPa·s at 25°C.

3. The thermally conductive composition according to claim 1, wherein, Component (A) is one or more organopolysiloxanes selected from organopolysiloxanes that do not have curing reactive groups with carbon-carbon double bonds in the molecule of (A1) and organopolysiloxanes that have curing reactive groups with carbon-carbon double bonds in the molecule of (A2).

4. The thermally conductive composition according to claim 1, wherein, Component (A) comprises at least one organopolysiloxane having a curing reactive group having a carbon-carbon double bond within the molecule (A2), and the thermally conductive composition contains (D) Organohydrogen polysiloxane: The amount of silicon atoms bonded to hydrogen atoms in component (D) is 0.2 to 5 moles, relative to 1 mole of the curing reactive groups with carbon-carbon double bonds contained in component (A); and (E) Catalyst for hydrosilylation reaction.

5. The thermally conductive composition according to claim 1, further comprising a component selected from... (C') General formula (2): R alk R 3 2SiO(R 3 2SiO) c R 3 2Si-R 4 -SiR 3 (3-d) (OR 5 ) d (where R) alk It is an alkenyl group, R 3 R is an independent, unsubstituted or substituted monovalent hydrocarbon group without a carbon-carbon double bond. 4 R is an oxygen atom or a divalent hydrocarbon group. 5 Independently, it consists of a hydrogen atom, alkyl, alkoxyalkyl, or acyl group, where c is an integer from 1 to 250 and d is an integer from 1 to 3. Siloxane compounds with a viscosity in the range of 10 to 10,000 mPa·s at 25°C, and whose molecular chain ends have alkenyl and hydrolyzable silane groups, as shown in the figure. (C'') Alkoxysilanes or their hydrolytic condensates having 6 or more carbon atoms in their molecule One or more of the components.

6. The thermally conductive composition according to claim 1, further comprising... (F) Heat resistance enhancer.

7. The thermally conductive composition according to claim 6, wherein, The component (F) is at least a portion of a heat-resistance imparting agent selected from (F1) phthalocyanine compounds and (F2) carbon black.

8. The thermally conductive composition according to claim 1, further comprising (G) at least one selected from fatty acids, fatty acid esters and fatty acid metal salts.

9. The thermally conductive composition according to claim 8, wherein, The component (G) is (G1) selected from one or more of stearic acid, alkali metal salts of stearic acid, and alkaline earth metal salts of stearic acid.

10. The thermally conductive composition according to claim 1, wherein, The component (B) is one or more thermally conductive fillers selected from zinc oxide powder, aluminum oxide powder and aluminum nitride powder.

11. The thermally conductive composition according to any one of claims 1 to 10, characterized in that, The composition or its cured reactant has a thermal conductivity of 9.0 W / mK or higher.

12. A thermally conductive component comprising the thermally conductive composition or its curing reactant as described in any one of claims 1 to 10.

13. A heat dissipation structure comprising the thermally conductive component as described in claim 12.

14. A heat dissipation structure comprising a heat dissipation component disposed on a heat dissipation component or a circuit board on which the heat dissipation component is mounted, by means of a thermally conductive composition or a cured product thereof as described in any one of claims 1 to 10.

15. The heat dissipation structure according to claim 13 or 14 is an electrical / electronic device.

16. The heat dissipation structure according to claim 13 or 14, wherein it is an electrical / electronic component or a secondary battery.

17. A method for manufacturing a thermally conductive composition according to any one of claims 1 to 10, comprising a step of mixing other components after mixing components (A) to (C) at least, and heating and mixing the mixture.

18. A method for manufacturing a heat dissipation structure, comprising a step of applying a thermally conductive composition according to any one of claims 1 to 10 to a heat dissipation component or a circuit board on which the heat dissipation component is mounted, and curing it at a temperature below 130°C.

19. A method of using a thermally conductive composition, characterized in that, The thermally conductive composition according to any one of claims 1 to 10 is filled into a package with a capacity of 10 to 300 ml selected from syringes, cartridges and dispensing machines, and extruded from the package for application to a heat dissipation part.

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