Silicone thermal conductive composition

Abstract

The present invention relates to a silicone thermal conductive composition comprising (A) 1 to 5 weight percent of a silicone wax; (B) a thermally conductive filler; (C) 0.5 to 6 weight percent of a wetting agent; (D) an antioxidant having melting point not more than 100°C; (E) a metal scavenger having melting point not more than 100°C; and (F) 0 to 3 weight percent of an optional additive and relates to an electronics package structure comprising the silicone thermal conductive composition.

Description

SILICONE THERMAL CONDUCTIVE COMPOSITIONCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to and the benefit of India Provisional Application No. 202411097579, filed on December 10, 2024, titled -SILICONE THERMAL CONDUCTIVE COMPOSITION,” and also claims priority to and the benefit of Japan Application No. 2025-091963 filed on June 2, 2025, titled “SILICONE THERMAL CONDUCTIVE COMPOSITION,” the disclosure of each of which is incorporated herein by reference in its entirety.FIELD OF THE INVENTION

[0002] The present invention relates to a silicone thermal conductive composition and an electronics package structure comprising the silicone thermal conductive composition.BACKGROUND ART

[0003] From LED (light emiting diode) to IGBT (insulated gate bipolar transistor), power modules are evolving to give high throughput, which means enhanced heat management is required for their longevity. A silicone-based thermal interface materials (TIMs) are widely used for this heat management.

[0004] A typical electronics package structure A including TIM is illustrated in FIG. 1. The electronics package structure illustratively includes a heat generating component, such as an electronic chip 1, and one or more heat dissipating components, such as a heat spreader 2, and a heat sink 3. Illustrative heat spreaders 2 and heat sinks comprise a metal, metal alloy, or metal-plated substrate, such as copper, copper alloy, aluminum, aluminum alloy, or nickel-plated copper.

[0005] The thermal interface materials, such as TIM 4 and TIM 5, provide a thermal connection between the heat generating component and the one or more heat dissipating components. Electronics package structure A includes a first TIM 4 connecting the electronic chip 1 and heat spreader 2. TIM 4 is typically referred to as a “TIM 1”. Electronics package structure A includes a second TIM 5 connecting the heat spreader 2 and heat sink 3. TIM 5 is typically referred to as a “TIM 2”. In another embodiment, electronics package structure A does not include a heat spreader 2, and a137239917.1TIM (not shown) connects the electronic chip 1 directly to the heat sink 3. Such a TIM connecting the electronic chip 1 directly to the heat sink 3 is typically referred to as a TIM 1.5.

[0006] Degradation of thermal interface materials typically occurs through polymer chain scission, such as illustrated in FIG. 2A. As shown in FIG. 2A, the initiation energy produces the initiation reaction RH— >R +H to form the radical R. This radical combines with an oxygen molecule to form the peroxide radical ROO . The peroxide radical can bond to a proton transferred from another R group to form the peroxide ROOH, as well as a new R. radical, which can combine with a new oxygen molecule. The branching reaction ROOH^RO +HO proceeds to form both a RO radical and a HO- radical. The RO and HO- are involved in scission of the remaining polymer chain, as well as embrittlement of the thermal interface material through unwanted crosslinking.

[0007] In a typical auto-oxidation cycle, the radical initiation reaction speed depends on provision of the initiation energy to produce the R- radical, as well as contaminants in the material. However, both the initiation reaction and the branching reaction are relatively slow due to relatively high activation energies involved in each reaction.

[0008] As shown in FIG. 2B, each of the initiation reaction and the branching reaction can be catalyzed by a metal ion. These metal ion catalyzed reactions have relatively low activation energies compared to the uncatalyzed reactions illustrated in FIG. 2A. This results in the generation of more radicals than the uncatalyzed cycle of FIG. 2A, which leads to faster degradation of the thermal interface material.

[0009] As illustrated in FIG. 1, at least one surface of a thermal interface material, such as TIM 4 or TIM 5, may be in direct contact with a metal surface, such as heat spreader 2 or heat sink 3. Such metal surfaces may provide metal ions to catalyze the initiation and branching reactions, such as from metal oxides that may form on the surface. For example, copper ions may interact with a polymer comprising the thermal interface material, particularly in the presence of heat, to form free radicals in the polymer that initiation chain scission that degrades the polymer during sendee.

[0010] WO 2017 / 051738 describes a thermosoftening and heat conductive silicone grease composition including a silicone wax having a melting point of 30-80 °C, an organopolysiloxane. a wetting agent and thermal conductive fdlers. The composition of WO 2017 / 051738 is used for the thermal interface material.237239917.1

[0011] WO 2016 / 004565 describes a thermal interface material including at least one polymer, at least one thermally conductive filler; an organic wax as phase change material, an antioxidant and at least one ion scavenger, wherein ion scavenger inhibits metal ion-induced free radical formation. In WO 2016 / 004565, although ion scavengers and antioxidants both reduce oxidative degradation of the TIM, ion scavengers are believed to function by capturing and binding metal ions in a complex such that the metal ions no longer have a net charge and are effectively disabled from participating in the metal-catalyzed reactions of FIG. 2B. In contrast, antioxidants are generally believed to function by transferring electrons to an oxidizing agent, such as the radicals of FIG. 2 A.SUMMARY OF THE INVENTIONTECHNICAL PROBLEM

[0012] As the silicone-based TIM tend to harden over time, it is important to optimize formulation to a softer formulation with desired thermal conductivity and thermal resistance. For high performing discrete electronic devices such as IGBT, there is need of high thermally conductive TIM with low bond line thickness.

[0013] However, compositions disclosed in WO 2017 / 051738 and WO 2016004565 do not provide high thermal conductivity along with low BLT and low TR. Further, the present inventors have found that in many cases high melting point of stabilizer such as antioxidant, and metal scavenger described in WO 2016 / 004565 can impart challenges to achieve low BLT at usable temperature range of belowlOO °C.

[0014] An object of the present invention is to provide a silicone thermal conductive composition which has high thermal conductivity along with low BLT and low TR.MEANS FOR SOLVING THE PROBLEMS

[0015] The inventors have found that the composition comprising a combination of low melting point antioxidant along with silicone wax, wetter and fillers can provide a silicone thermal conductive composition which has high thermal conductivity along with low BLT and low TR.

[0016] The present invention provides the following items [1] to

[0019] ,[1] A silicone thermal conductive composition comprising:(A) 1 to 5 w eight percent of a silicone wax;337239917.1(B) a thermally conductive filler;(C) 0.5 to 6 weight percent of a wetting agent;(D) an antioxidant having melting point not more than 100 °C;(E) 0 to 3 weight percent of an optional additive other than (F); and(F) optionally a metal scavenger having melting point not more than 100 °C; wherein the silicone thermal conductive composition does not comprise a metal scavenger having melting point more than 100 °C.[2] The silicone thermal conductive composition according to item [1]. wherein the component (A) is an alkylated poly dimethylsiloxane.[3] The silicone thermal conductive composition according to item [1] or [2], wherein the component (C) is a hydrolyzable organopolysiloxane (I) represented by the formula (I-i):(Formula I-i) or a hydrolysable polyorganosiloxane represented by the formula (I-ii):(Formula I-ii).37239917.1[4] The silicone thermal conductive composition according to any of items [1] to [3], wherein the component (D) is selected from hindered phenols, thioethers, and phosphites and / or a combination thereof.[5] The silicone thermal conductive composition according to anyone of items [1] to[4], wherein the component (D) is selected from the group consisting of didodecyl 3,3’- thiodipropionate, octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate, and a combination thereof.[6] The silicone thermal conductive composition according to anyone of items

[0001] to[5], wherein the component (D) is present in an amount of up to 5 weight percent based on the total weight of the composition.[7] The silicone thermal conductive composition according to anyone of items [1] to[6], wherein the component (F) is selected from the group consisting of 5-methyl-lH- benzotriazole, N, N-bis(2-ethylhexyl)-4-methyl-lH-benzotriazole-l-methanamine, 2,5-dimercapto-l,3,4-thiadiazole, and a combination thereof.[8] The silicone thermal conductive composition according to anyone of items [1] to[7], wherein the component (F) is present in an amount of up to 5 weight percent based on the total weight of composition.[9] The silicone thermal conductive composition according to anyone of items [1] to[8], wherein the component (B) is a metal oxide or a non-oxide filler.

[0010] The silicone thermal conductive composition according to anyone of items [1] to[9], wherein the component (B) is a metal oxide, and the metal oxide filler is selected from the group consisting of alumina, magnesia, ceria, hafhia, lanthanum oxide, neodymium oxide, samaria, praseodymium oxide, thoria, urania, yttria, zinc oxide, zirconia, and a combination thereof.

[0011] The silicone thermal conductive composition according to anyone of items [1] to [9], wherein the component (B) is a non-oxide filler, and the non-oxide filler is selected from the group consisting of aluminum, metal boride, a metal carbide, a metal nitride, a metal silicide, carbon black, graphite, expanded graphite, carbon fiber, diamond, carbon nanotubes, graphite fiber, and a combination thereof.

[0012] The silicone thermal conductive composition according to anyone of items [1] to [9], wherein the component (B) is selected from the group consisting of a zinc oxide, aluminum filler, and a combination thereof.

[0013] The silicone thermal conductive composition according to anyone of items [1] to

[0012] , wherein the particle size of the component (B) is from 0.01 pm to 500 pm.537239917.1

[0014] The silicone thermal conductive composition according to anyone of items [1] to

[0011] , wherein the component (B) is present in an amount of from 80 weight percent to 99 weight percent based on the total weight of the composition.

[0015] The silicone thermal conductive composition according to anyone of items [1] to

[0014] , wherein the component (E) is selected from the group consisting of flame retardants, crosslinking agents, viscosity modifiers, thermal stabilizers, colorants, and a combination thereof.

[0016] The silicone thermal conductive composition according to anyone of items [1] to

[0015] , wherein the component (E) is a carbosilane represented by the formula:wherein n is a number of 10 to 200.

[0017] The silicone thermal conductive composition according to anyone of items [1] to

[0016] , wherein the composition has a thermal resistance <10.0 mm2K / W.

[0018] The silicone thermal conductive composition according to anyone of items [1] to

[0017] , wherein when the composition has a thermal resistance <15.0 mm2K / W after aging-treatment at 150 °C for lOOOh on aluminum substrate or on copper substrate.

[0019] The silicone thermal conductive composition according to anyone of items [1] to

[0018] , wherein the composition has a viscosity of 1300Pa s or less after aging-treatment at 150 °C for lOOOh on aluminum substrate or on copper substrate, wherein the viscosity of the composition is measured using Rheometer at 60 °C at shear rate of 2 s'1w ith 0.3 mm gap with parallel plate.

[0020] An electronics package structure comprising the silicone thermal conductive composition according to anyone of items [1] to

[0019] , a heat generating component and one or more heat dissipating components, wherein the silicone thermal conductive composition provides a thermal connection between the heat generating component and the one or more heat dissipating components, and wherein the composition has a bond line thickness <50 microns.637239917.1EFFECT OF THE INVENTION

[0017] The present invention provides a silicone thermal conductive composition which has high thermal conductivity along with low BLT and low TR.BRIEF DESCRIPTION OF THE DRAWINGS

[0018] FIG. 1 illustrates a typical electronics package structure.

[0019] FIG. 2A illustrates a typical degradation mechanism for thermal interface materials.

[0020] FIG. 2B illustrates a metal-catalyzed degradation mechanism for thermal interface materials.DETAILED DESCRIPTION

[0021] Reference will now be made to exemplar}' embodiments, examples of which are illustrated in the accompanying drawings. It is to be understood that other embodiments may be utilized, and structural and functional changes may be made. Moreover, features of the various embodiments may be combined or altered. As such, the following description is presented by way of illustration only and should not limit in any way the various alternatives and modifications that may be made to the illustrated embodiments. In this disclosure, numerous specific details provide a thorough understanding of the subject disclosure. It should be understood that aspects of this disclosure may be practiced with other embodiments not necessarily including all aspects described herein, etc.

[0022] As used herein, the words ‘“example" and “exemplar}’" means an instance, or illustration. The words “example" or “exemplary" do not indicate a key or preferred aspect or embodiment. The word “or" is intended to be inclusive rather than exclusive, unless context suggests otherwise. As an example, the phrase “A employs B or C,” includes any inclusive permutation (e.g., A employs B; A employs C; or A employs both B and C). As another matter, the articles “a" and “an" are generally intended to mean “one or more” unless context suggest otherwise.

[0023] As used herein, the term:

[0024] “alkyl" includes straight, branched, and cyclic monovalent hydrocarbon groups, which may be substituted with a heteroatom or heteroatom containing group;737239917.1

[0025] ‘‘alkylene'’ includes straight, branched, and cyclic divalent hydrocarbon groups, which may be substituted with a heteroatom or heteroatom containing group;

[0026] ‘'aryl” includes any monovalent aromatic hydrocarbon group, which may be substituted with a heteroatom or heteroatom containing group; this term also includes fused systems containing an aromatic group;

[0027] “arylene’" includes any divalent aromatic hydrocarbon group, which may be substituted with a heteroatom or heteroatom containing group this term also includes fused systems containing an aromatic group;

[0028] “aralkyl” include straight, branched, and cyclic monovalent hydrocarbon groups substituted with an ary l substituent;

[0029] “cyclo” or “cyclic” alkyl includes a monovalent cyclic hydrocarbon and includes, free cyclic groups, bicyclic groups, tricyclic groups, and higher cyclic structures, as well as bridged cyclic groups, fused cyclic groups, and fused cyclic groups containing at least one bridged cyclic group;

[0030] “cyclo” or “cyclic” alkylene includes a divalent cyclic hydrocarbon and includes, free cyclic groups, bicyclic groups, tricyclic groups, and higher cyclic structures, as well as bridged cyclic groups, fused cyclic groups, and fused cyclic groups containing at least one bridged cyclic group;

[0031] “hetero"’ as used refer to an atom or in conjunction with another group includes atom or group containing an atom such as oxygen, nitrogen, sulfur, silicon, phosphorus, boron, etc.

[0032] 1. Silicone thermal conductive composition

[0033] In one embodiment, the present invention provides a silicone thermal conductive composition comprising:(A) 1 to 5 weight percent of a silicone wax;(B) a thermally7conductive filler;(C) 0.5 to 6 weight percent of a wetting agent;(D) an antioxidant having melting point not more than 100 °C;(E) 0 to 3 weight percent of an optional additive other than (F); and(F) optionally a metal scavenger having melting point not more than 100 °C; wherein the silicone thermal conductive composition does not comprise a metal scavenger having melting point more than 100 °C.

[0034] (1) (A) silicone wax837239917.1

[0035] The component (A) is a silicone wax. The component (A) is a component that serves as a base polymer in the composition. The silicone wax serving as the component (A) may be any silicone wax.

[0036] The component (A) may have a melting point of from 30 °C to 80 °C. The component (A) may have a viscosity of from 10 Pa s to 50 Pa s at 60 °C with the shear rate of 1 s'1with 0.5 mm gap using parallel plate. The viscosity can be measured using Haake RS-600 Rheometer.

[0037] In embodiments, component (A) is an alkylated polydimethylsiloxane. In the specification, “alkylated poly dimethylsiloxane” refers to a polydimethylsiloxane in which at least one methyl group is replaced with the long chain alkyl group. In the specification, “long chain alkyl group” refers to an alkyl group having from 10 to 50 carbon atoms.

[0038] In embodiments, component (A) is obtained by a hydrosilylation reaction between an alkene compound (preferably, a-olefm) and a SiH bond-containing silicone compound (preferably, silicone dihydride). Here, the alkene compound is not an alkenyl group-containing silicone compound. Thus, the alkylated polydimethylsiloxane that is the preferred component (A) preferably has no Si- alkylene-Si bond. The component (A) preferably does not have Si-alkylene-Si bond, alkoxy group or alkenyl group.

[0039] A hydrosilylation reaction between an alkene and a SiH bond-containing silicone compound is carried out by a known method.

[0040] In the component (A), the alkyl group bonded to the terminal vinyl group on the a-olefm is preferably one having from 10 to 50 carbon atoms, more preferably one having from 22 to 47 carbon atoms. Here, the alkyl group is preferably linear alkyl group, although they may be branched. a-Olefins in a plurality of types may be mixed together.

[0041] An organohydrogenpolysiloxane may be used as the SiH bondcontaining silicone compound. The SiH bond may be present either at an end or in an intermediate unit. Example of the organohydrogenpolysiloxane includes a polydimethylsiloxanes capped at both ends of the molecular chain with dimethylhydrogensiloxy groups, dimethylsiloxane / methylhydrogensiloxane copolymers capped at both ends of the molecular chain with trimethylsiloxy groups, dimethylsiloxane / methylhydrogensiloxane copolymers capped at both ends of the molecular chain with dimethylhydrogensiloxy groups, organosiloxane copolymers937239917.1consisting of siloxane units of the formula (CH3)3SiOi / 2, siloxane units of the formula (CH3)2HSiOi / 2and siloxane units of the formula SiO4 / 2, and mixtures of two or more thereof.

[0042] For example, the component (A) can be prepared by standard hydrosilylation reaction using Karstedt’s catalyst and the reaction between a silicone dihydride compound and an alkene compound as shown in below reaction scheme.

[0043]

[0044] Here, n=20-40 and m=20-45. The alkene compound was procured from Chevron Phillips Chemical Company, and the chemical name is Alphaplus C30+.

[0045] The reaction of an alkene compound with a SiH bond-containing silicone compound is preferably carried out with amounts thereof such that the number of hydrogen atoms bonded to silicon atoms on the SiH bond-containing silicone compound per vinyl group on the a-olefin is from 0.8 to 1.4.

[0046] The component (A) is present in an amount of 1 to 5 weight percent based on the total weight of composition. The component (A) can be present in an amount of 1.5 to 4 weight percent based on the total weight of composition.

[0047] (2) (B) Thermally conductive filler

[0048] The component (B) is a thermally conductive filler. Examples of thermally conductive fillers include, but are not limited to. alumina, magnesia, ceria, hafnia, lanthanum oxide, neodymium oxide, samaria, praseodymium oxide, thoria, urania, yttria, zinc oxide, zirconia, silicon aluminium oxynitride, borosilicate glasses, barium titanate, silicon carbide, silica, boron carbide, titanium carbide, zirconium carbide, boron nitride, silicon nitride, aluminium nitride, titanium nitride, zirconium nitride, zirconium boride, titanium diboride, aluminium dodecaboride, barytes, barium sulfate, asbestos, barite, diatomite, feldspar, gypsum, hormite, kaolin, mica, nepheline1037239917.1syenite, perlite, phyrophyllite, smectite, talc, vermiculite, zeolite, calcite, calcium carbonate, wollastonite, calcium metasilicate, clay, aluminium silicate, talc, magnesium aluminium silicate, hydrated alumina, hydrated aluminium oxide, silica, silicon dioxide, titanium dioxide, glass fibers, glass flake, clays, exfoliated clays, or other high aspect ratio fibers, rods, or flakes, calcium carbonate, zinc oxide, magnesia, titania, calcium carbonate, talc, mica, wollastonite, alumina, aluminium nitride, graphite, expanded graphite, metallic powders, e.g., aluminium, copper, bronze, brass, etc., fibers or whiskers of carbon, graphite, silicon carbide, silicon nitride, alumina, aluminium nitride, zinc oxide, nano-scale fibers such as carbon nanotubes, boron nitride nanosheets, zinc oxide nanotubes, etc., and mixtures of two or more thereof. In one embodiment, the thermally conductive filler has a low electrical conductivity or is electrically insulating.

[0049] In embodiments, component (B) is selected from a metal oxide or a nonoxide filler.

[0050] The metal oxide filler may be selected from the group consisting of alumina, magnesia, ceria, hafnia, lanthanum oxide, neodymium oxide, samaria, praseodymium oxide, thoria, urania, yttria, zinc oxide, zirconia, and a combination thereof.

[0051] The non-oxide filler may be selected from the group consisting of aluminum, metal boride, a metal carbide, a metal nitride, a metal silicide, carbon black, graphite, expanded graphite, carbon fiber, diamond, carbon nanotubes, graphite fiber, and a combination thereof.

[0052] In embodiments, component (B) is selected from the group consisting of a zinc oxide, aluminum filler, and a combination thereof.

[0053] The particle size of the component (B) may be chosen as desired for a particular purpose or intended application. In embodiments, the component (B) can have an average particle size of from about 0.01 pm to about 500 pm; from about 0.1 to about 250 pm; from about 1 to about 100 pm; from about 5 to about 75 pm; or even from about 10 to about 50 pm.

[0054] The average particle size is typically supplied or reported by the material provider. It can be determined by measuring the particle size distribution using laser diffraction and scattering, following the JIS R1629 standard. In the present invention, the median diameter (D50) on a volume basis, obtained from these measurements, is used as the average particle diameter.1137239917.1

[0055] The composition may comprise a combination of the component (B) of different average particle sizes. Such combinations may be chosen as desired for a particular purpose or intended application. In one embodiment, the composition comprises a first thermally conductive filler having an average particle size from about 0.05 to about 1 pm; a second thermally conductive filler having an average particle size of about 0.2 pm to about 5 pm; and optionally a third thermally conductive filler having an average particle size of about 1 pm to about 50 pm. The first, second, and third fillers may be the same or different from one another in terms of the chemical makeup of the filler.

[0056] The component (B) may be present in an amount of from about 80 weight percent to about 98.5 weight percent, from about 82 weight percent to about 96 weight percent, or from about 85 weight percent to about 95 weight percent based on the total weight of the composition.

[0057] (3) (C) Wetting agent

[0058] The component (C) is a wetting agent. The component (C) is a component that serves as a surface treating agent for the component (B). The component (C) may be a hydrolyzable organopolysiloxane having the hydrolyzable group.

[0059] In embodiments, component (C) is represented by the following general formula (1):whereinR1is a group having an alkoxysilyl group having 1 to 4 carbon atoms, R2is a linear organosiloxy group represented by the following general formula (2):37239917.1wherein each R4is independently a monovalent hydrocarbon group having 1 to 12 carbon atoms,Y is a group selected from the group consisting of R4and an aliphatic unsaturated group, and d is an integer of 2 to 60, each X is independently a divalent hydrocarbon group having 2 to 10 carbon atoms, each of a and b is independently an integer of 1 or more, c is an integer of 0 or more, wherein a + b + c is an integer of 4 or more, and each R3is independently a monovalent hydrocarbon group having 1 to 6 carbon atoms or a hydrogen atom.

[0060] In a compound of formula (1), the unit containing R1, the unit containing R2, and the unit represented by SiR32<D are not necessarily arranged as shown in the general formula (1) above, and, for example, the unit represented by SiR32O may be present between the unit containing R1and the unit containing R2.

[0061] The siloxane compound having the cyclic structure represented by the general formula (1) can have a large number of hydrolysable groups introduced into the cyclic structure, and further has the hydrolysable groups concentrated in the position of the structure, and therefore is considered to have an increased treatment efficiency for component (B), enabling higher filling. In addition, the siloxane compound per se has high heat resistance, and therefore can cause the thermally conductive silicone composition to have high heat resistance. Further, the siloxane compound represented by the general formula (1) has an advantage in that the compound can be easily obtained by subjecting to addition reaction, for example, a cyclic siloxane containing a hydrogen group, a siloxane having a vinyl group at one end, and a silane compound containing a vinyl group and a hydrolysable group.

[0062] R1is a group having an alkoxysilyl group having 1 to 4 carbon atoms, which is a hydrolysable functional group. R1may be directly bonded to X with silicon, but may be bonded through a linking group, such as an ester linkage. R1is preferably a group having the following structure.1337239917.1

[0063] In view of a tendency toward a further improvement of the treatment efficiency for the component (B), R1is, in embodiments, selected from a group of a structure having two or more alkoxysilyl groups, especially having three or more alkoxysilyl groups. Further, in view of easy availability of the raw material, R1may contain a methoxysilyl group.

[0064] R2is a linear organosiloxy group represented by the general formula (2). In the general formula (2), d is an integer of 2 to 60. d is 2 to 60, and therefore the effect on the fluidity is improved, enabling high incorporation, so that the viscosity of the siloxane compound per se can be reduced. Each R4is independently a monovalent hydrocarbon group having 1 to 12 carbon atoms, and examples of R4's include linear or branched Cl-12 alkyl groups, and aryl groups, such as phenyl and naphthyl. Further, the hydrocarbon group may be substituted with a halogen, such as chlorine, fluorine, or bromine, and examples of such groups include perfluoroalkyl groups, such as a trifluoromethyl group. In view of easy synthesis of the compound, R4is preferably a methyl group. Y is a group selected from the group consisting of R4, and an aliphatic unsaturated group. The aliphatic unsaturated group preferably has 2 to 10 carbon atoms, more preferably 2 to 6 carbon atoms. Further, from the viewpoint of facilitating the curing reaction, the aliphatic unsaturated group preferably has a double bond at the end thereof. In view of easy synthesis of the compound, Y is preferably a methyl group or a vinyl group.

[0065] R1and R2are individually bonded through group X to the cyclic siloxane portion of the siloxane represented by the general formula (1). Group X is a divalent hydrocarbon group having 2 to 10 carbon atoms, and examples of such groups include alkylene groups, such as -CH2CH2-. -CH2CH2CH2-, -CH2CH2CH2CH2CH2CH2-, - CH2CH(CH3)-, and -CH2CH(CH3)CH2-. In view of easy synthesis of the compound, X is preferably -CH2CH2- or -CH CH(CH3)-.1437239917.1

[0066] Each R3is independently a monovalent hydrocarbon group having 1 to 6 carbon atoms or a hydrogen atom. R3's may be the same or different. R3is preferably a methyl group or a hydrogen atom in view of easy synthesis of the compound.

[0067] The subscript a is an integer of 1 or more. In embodiments, the subscript a is 1. The subscript b is an integer of 1 or more. In embodiments, the subscript b is 1 or 2. The subscript c is an integer of 0 or more. In embodiments, the subscript c is 0 to 2. Further, the total of a + b + c is an integer of 4 or more, and, in embodiments, is 4 in view of ease synthesis of the compound.

[0068] In embodiments, the component (C) is a hydrolyzable organopolysiloxane represented by a compound of the formula (I-i) or formula (I-ii). The component (C) can be prepared by the process disclosed in W02005 / 030874 Al.

[0069] (Formula I-ii)

[0070] The component (C) is present in an amount of 0.5 to 6.0 weight percent based on the total weight of composition. The component (C) can be present in an amount of 1.5 to 5.0 weight percent based on the total weight of composition.

[0071] (4) (D) Antioxidant having melting point not more than 100°C1537239917.1

[0072] The component (D) is an antioxidant having melting point not more than 100°C. When the composition comprises an antioxidant having melting point more than 100 °C, both higher BLT (more than 150 microns) and higher TR (more than 30.0 mm2K / W) are observed. With respect to the component (D), there is no particular limitation as long as the component (D) has melting point not more than 100 °C. In embodiments, the component (D) is chosen from didodecyl 3,3’-thiodipropionate, octadecyl 3-(3.5-ditert-butyl-4-hydroxyphenyl) propionate, tris(2.4-di-tert-butylphenyl) phosphite, 2,4,6-tris(3’,5’-di-tert-butyl-4’-hydroxybenzj4) mesitylene, triethylene glycol bis[3-(3-tert-butyl-4-hydroxy-5-methylphyenyl)propionate], dioctadecyl 3,3’- thiodipropionate, pentaerythritol tetrakis[3-laurylthiopropionate], or a combination of two or more thereof.

[0073] The component (D) can be present in an amount of up to 5 weight percent based on the total weight of the composition. In one embodiment, the component (D) can be present in an amount of from about 0.05 weight percent to about 5 weight percent, or from about 0. 1 weight percent to about 2 weight percent based on the total weight of the composition.

[0074] (5) (E) Optional additive other than (F)

[0075] The component (E) is an optional additive other than (F). Examples of the component (E) include, but are not limited to, flame retardants, crosslinking agents, viscosity modifiers such as a carbosilane, thermal stabilizers, colorants, or a combination thereof. These components are can be appropriately selected from conventionally known components.

[0076] The component (E) can be a carbosilane which is a reaction product between an alkenyl group-containing silicone compound and a SiH bond-containing silicone compound. Therefore, the carbosilane has -Si-alkylene-Si- bond. In embdoiments, the carbosilane does not have alkoxy group or alkenyl group.

[0077] The carbosilane may have a viscosity in the range of from 0.01 Pa s to below 10 Pa s at 60 °C with the shear rate of 1 s’1with 0.5 mm gap using parallel plate.

[0078] In embodiments, the carbosilane has the following structure:1637239917.1where n=l 0-200 and a viscosity in the range of 20 mPa s to 1000 mPa s.

[0079] The carbosilane of the above structure may be prepared by a hydrosilylation reaction between di-alkenyl polysiloxane and 1.1.1.3, 5,5,5- Heptamethyltrisiloxane using 5 ppm of Karstedt’s catalyst.

[0080] 1,1,1,3,5,5,5-Heptamethyltrisiloxane was obtained from Sigma-Aldrich (MERCK). The reaction scheme is shown below.

[0081] The component (E) can be present in an amount of 0 to 3 weight percent based on the total weight of composition.

[0082] (6) (F) Metal scavenger having melting point not more than 100 °C

[0083] The component (F) is a metal scavenger having a melting point of not more than 100 °C. The metal scavenger is also called as ion-scavenger. The component (F) is optional component. The composition may not comprise the component (F). The composition may comprise the component (F) in the viewpoint of heat stability. In other words, when the composition comprises the component (F), the resulting composition has superior thermal stability, wettability, or spreadability.

[0084] The melting point of the component (F) is generally not more than 100 °C. In embodiments, the melting point of component (F) may be from 0°C to 100 °C in the viewpoint of the thermal resistance. The melting point of the component (F) is may be from -80 °C to 100 °C, and in some embodiments from -80 °C to 85 °C in the viewpoint of BLT.1737239917.1

[0085] With respect to the component (F), there is no particular limitation as long as the component (F) has melting point not more than 100 °C. The component (F) includes, but is not limited to, amine type metal scavengers, amide type metal scavengers, phenolic type metal scavengers, and thio ether type metal scavengers.

[0086] Examples of the component (F) include, but is not limited to, 5-Methyl- IH-benzotriazole, N,N-bis(2-ethylhexyl)-ar-methyl-lH-benzotriazole-l-methanamine, 2.5-dimercapto-l,3,4-thiadiazole derivative). 3-(3,5-Di-tert-butyl-4- hydroxyphenyl)Propanehydrazide, N,N'-(Hexane-l ,6-diyl)bis[3-(3,5-di-tert-butyl-4- hydroxyphenyl) propanamide, Oxalylbis(azanediyl)]bis(ethane-2,l-diyl) Bis[3-(3,5-di- tert-butyl-4-hydroxyphenyl)propanoate and 2,5-bis(tert-dodecyldithio)-l,3,4- thiadi azole.

[0087] In embodiments, the component (F) is chosen from 5-Methyl-lH- benzotriazole (Tolyltriazole), N,N-bis(2-ethylhexyl)-4-methyl-lH-benzotriazole-l- methanamine, 2,5-dimercapto-l,3,4-thiadiazole derivative or a combination of two or more thereof.

[0088] In the composition, the component (F) can be present in an amount of up to 5 weight percent based on the total weight of composition. In one embodiment, the component (F) can be present in an amount of from about 0.05 weight percent to about 5 weight percent, from about 0. 1 weight percent to about 2 weight percent.

[0089] (7) Metal scavenger having melting point more than 100 °C

[0090] The silicone thermal conductive composition does not comprise a metal scavenger having melting point more than 100 °C. When the composition comprises a metal scavenger having melting point more than 100 °C, both higher BLT (more than 150 microns) and higher TR (more than 30.0 mm2K / W) are observed.

[0091] Examples of metal scavengers having melting point more than 100 °C include N,N'-(Hexane-l,6-diyl)bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl) propanamide, Oxalylbis(azanediyl)]bis(ethane-2,l-diyl) Bis[3-(3,5-di-ter / -butyl-4- hydroxyphenyl)propanoate, and 2'.3-bis[[3-[3,5-di-tert-butyl-4- hy droxy phenyl ] propiony 1] ] propi onohy drazi de.

[0092] (8) Thermal conductivity (TC)

[0093] The silicone thermal conductive composition has high thermal conductivity7. In another embodiment, the silicone thermal conductive composition has a thermal conductivity7of 5.0 W / mK or more. If the silicone thermal conductive1837239917.1composition has a thermal conductivity of 5.0 W / mK or more, it can be said that the composition has high thermal conductivity.

[0094] (9) Bond line thickness (BLT)

[0095] The silicone thermal conductive composition has a low bond line thickness (low BLT). In another embodiment, the silicone thermal conductive composition has a bond line thickness below 50 pm. If the silicone thermal conductive composition has a bond line thickness below 50 pm. it can be said that the composition has low BLT. The silicone thermal conductive composition preferably has BLT below 30 pm.

[0096] (10) Thermal resistance (TR)

[0097] The silicone thermal conductive composition has low thermal resistance (low TR). In another embodiment, the silicone thermal conductive composition has the thermal resistance of less than 10 mm2K / W. If the silicone thermal conductive composition has the thermal resistance of less than 10 mm2K / W, it can be said that the composition has low TR. The silicone thermal conductive composition preferably has a thermal resistance of less than 9.9 mm2K / W.

[0098] (11) Thermal stability

[0099] The silicone thermal conductive composition is preferably stable at high temperature for 1000 h on aluminium substrate or on copper substrate. The silicone thermal conductive composition is preferably stable at 150 °C for 1000 h on aluminium substrate or on copper substrate. In the present invention, the silicone thermal conductive composition maintains the stability when the thermal resistance (TR) is 15 mm2K / W or less after the compositions is treated at 150 °C for 1000 h on aluminium substrate or copper substrate. From the viewpoint of the stability, the thermal resistance (TR) is preferably less than 10 mm2K / W after the compositions is treated at 150 °C for 1000 h on aluminium and copper substrates.

[0100] (12) Wettability or spreadability7

[0101] The silicone thermal conductive composition preferably maintains the wettability or spreadability at high temperature for lOOOh on aluminium substrate or on copper substrate. In the present invention, the silicone thermal conductive composition maintains the wettability or spreadability when the viscosity is 1300 Pa s or less after the compositions is treated at 150 °C for 1000 h on aluminium substrate or copper substrate. Here, the viscosity is measured using Haake RS-600 Rheometer at 60 °C at shear rate of 2 s'1with 0.3 mm gap with parallel plate.1937239917.1

[0102] (13) Preparation of composition

[0103] The silicone thermal conductive composition can be produced by uniformly mixing components (A) to (D), which are essential components, and components (E) and (F), which are an optional component, by a mixing means, such as a universal kneading machine or a kneader. The silicone thermal conductive composition can be preferably produced by the method described in the following Examples.

[0104] (14) Application

[0105] The silicone thermal conductive composition is used for the thermosoftening and heat conductive silicone grease composition. The silicone thermal conductive composition is preferably used for a phase change thermal interface material (PCTIM). The silicone thermal conductive composition can be used as a radiator part of an electronic part for, for example, an electronics package structure.

[0106] (15) An electronics package structure

[0107] In another embodiment, the present invention directs to an electronics package structure comprises the above-mentioned silicone thermal conductive composition, a heat generating component and one or more heat dissipating components, wherein the silicone thermal conductive composition provides a thermal connection between the heat generating component and the one or more heat dissipating components, and wherein the composition has a bond line thickness (BLT) below 50 pm.

[0108] Example of the heat generating component includes an electronic chip 1 illustrated in FIG. 1. Example of the heat dissipating component includes a heat spreader 2, and a heat sink 3 illustrated in FIG. 1. The preferred embodiments for the silicone thermal conductive composition and the BLT of the composition are as mentioned above.EXAMPLES

[0109] The following examples are intended to illustrate aspects and embodiments of the silicone thermal conductive composition. All parts and percentages are by weight and all temperatures are in Celsius unless explicitly stated otherwise. All patents and other publications referred to in the instant application are incorporated herein by reference in their entireties. The disclosed embodiments are merely for2037239917.1illustrative purposes and not intended to limit the scope of the invention or the subject matter set forth in the claims. Modifications may occur to those skilled in the art and to those who may make and use the invention.

[0110] [Examples 1 to 6, Comparative Examples 1 to 4]

[0111] (Preparation of silicone composition)Silicone thermal conductive compositions were prepared by mixing the silicone wax. wetting agent, antioxidants (AO), metal scavengers (MS) and fillers as shown in Table 1 . The components other than fillers were mixed and was heated up to 80 °C to melt polymer (that is, the silicone wax) and fillers were added to it and blended it thoroughly. The composition was cooled to room temperature (25 °C) to prepare the thermally conductive silicone composition.

[0112] Then, properties of the bulk TC (thermal conductivity), TR (thermal resistance), BLT (bond line thickness), stability and wettability of the composition were evaluated by the following method.

[0113] (Method for evaluation)

[0114] 1. TC (thermal conductivity), TR (thermal resistance) and BLT (bond line thickness)The bulk TC, TR and BLT were measured at 80 °C using TIMA5 (thermal interface material analyser) instrument (ASTM D5470) from NANOTEST by using two Aluminum test heads and T3Ster DynTIM Tester (ASTMD5470) from Mentor Graphics. BLT was measured at 80 °C where the 1 g of sample was placed between two Aluminum test heads which has the area of 132.28 mm2and applied 300 N force.

[0115] 2. Stability and Wettability

[0116] 2-1. Preparation of aged composition on Al (aluminum) substrate0.5 g of the composition was placed between Al and glass substrate using 1 mm thickness spacer and clamped. Then, the aging treatment was performed by placing the sample vertically in the oven at 150 °C for 1000 h and followed by cooling at room temperature (25 °C) for 24h. Thus, the aged composition on Al substrate was obtained. Then, the aged composition was collected from the aged sample. Then, stability and wettability of the aged composition was evaluated by the following method. Here, the aged composition on Al substrate corresponds to the silicone thermal conductive composition after aging-treatment on Al substrate.

[0117] 2-2. Preparation of aged composition on Cu (copper) substrate2137239917.10.5 g of the composition was placed between Cu and glass substrate using 1 mm thickness spacer and clamped. Then, the aging treatment was performed by placing the sample vertically in the oven at 150 °C for 1000 h and followed by cooling at room temperature (25 °C) for 24h. Thus, the aged sample on Cu substrate was obtained. Then, the aged composition was collected from the aged sample. Then, stability and wettability of the composition was evaluated by the following method. Here, the aged composition on Cu substrate corresponds to the silicone thermal conductive composition after aging-treatment on Cu substrate.

[0118] 2-3. Evaluation of StabilityThe TR for the aged composition were measured. The aged composition having a thermal resistance (TR) below 15 mm2K / W was judged to have excellent stability. If the sample became powdery after aging for lOOOh at 150 °C, we can not measure the TR.

[0119] 2-4. Evaluation of WettabilityThe viscosity of the aged composition was measured using Haake RS- 600 Rheometer at 60 °C at shear rate of 2 s'1with 0.3 mm gap with parallel plate. The aged composition having a viscosity of 1300Pa s or less was judged to have excellent wettability. If the sample became powdery' after aging for lOOOh at 150 °C, we can not measure the viscosity.

[0120] 2-5. Evaluation of SpreadabilityThe spreadability' the aged composition of Examples 3 to 6 were measured. The spreadability was measured for the aged composition on Al substrate at 80 °C by visual inspection. Rating was given as 0 to 3 with rating 3 as very soft, rating 2-is soft, rating 1- is less soft, rating 0- is dry’ powdery.

[0121] The results are described in Tables 1 to 5.

[0122] Table 12237239917.1

[0123] Table 22337239917.1

[0124] Table 3

[0125] Table 437239917.1

[0126] Table 5

[0127] The components used in the Examples (Ex) and Comparative Examples (Comp. Ex) are as follows.

[0128] (A) Silicone wax

[0129] The silicone wax is SF1642 (an alkylated polydimethyl siloxane) procured from Momentive Performance materials. The silicone wax has the melting point of 57 °C and the viscosity of 30 Pa s at 60 °C with the shear rate of 1 s'1with 0.5 mm gap using parallel plate.

[0130] (B) Conductive filler

[0131] ZnO filler was procured from ZOCHEM and the average particle size (D50) is 0. 1 -0.5 pm.

[0132] Al Filler-1 was procured from Toyal and the average particle size (D50) of Al Filler- 1 is 1-2 pm.

[0133] Al Filler-2 was procured from Toyal and the average particle size (D50) of Al Filler-2 is 13-15 pm.

[0134] (C) Wetting agent

[0135] The wetting agent is a hydrolyzable organopolysiloxane represented by a compound of the formula (I-i). The compound of the formula (I-i) was prepared by the process disclosed in W02005 / 030874 Al.2537239917.1

[0136] (Formula I-i)

[0137] (D) Antioxidant selected from AO-1 to AO-7

[0138] AO-1 is a Irganox 1076 (Octadecyl 3-(3,5-ditert-butyl-4-hydroxyphenyl) propionate) antioxidant having a melting point of 50-52 °C procured from Sigma- Aldrich (MERCK).

[0139] AO-2 is a Irganox PS800 (Didodecyl 3,3'-thiodipropionate) antioxidant having a melting point of 40-42 °C and procured from Sigma-Aldrich (MERCK).

[0140] AO-3 is a Irgafos 168 (Tris(2,4-di-tert-butylphenyl) phosphite) antioxidant having a melting point of 181-184 °C and procured from Sigma-Aldrich (MERCK).

[0141] AO-4 is a 2,4,6-Tris(3,.5'-di-tert-butyl-4'-hydroxybenzyl) mesitylene antioxidant having a melting point of 240-245 °C and procured from TCI Chemicals.

[0142] AO-5 is a Triethylene Glycol Bis|3-(3-tert-butyl-4-hydro\y-5- methylphenyl)propionate] antioxidant having a melting point of 79 °C and procured from TCI chemicals

[0143] AO-6 is a Dioctadecyl 3,3'-Thiodipropionate antioxidant having a melting point of 65 °C and procured from TCI chemicals

[0144] AO-7 is a Pcntaerythritol Tetrakis[3-laurylthiopropionate] antioxidant having a melting point of 51 °C and procured from TCI chemical

[0145] (D’) antioxidant other than (D)

[0146] (E) is a carbosilane represented by the formula (II), wherein n is 80.37239917.1

[0147] The carbosilane was prepared by hydrosilylation reaction between dialkenyl polysiloxane and 1,1,1,3.5,5,5-Heptamethyltrisiloxane using 5 ppm ofKarstedt’s catalyst and the reaction was carried out at 75 °C for 5 hours under toluene as solvent. 1,1,1,3,5,5,5-Heptamethyltrisiloxane was obtained from Sigma-Aldrich (MERCK). Reaction scheme was shown below.

[0148] (F) Metal scavenger

[0149] MS-1 is 5-Methyl-lH-benzotriazole (Tolyltriazole), a metal scavenger having a melting point of 80-82 °C, procured from Sigma- Aldrich (MERCK).

[0150] MS-4 is CUV AN 303, chemical composition is N, N-bis(2-ethylhexyl)-4-methyl-lH-benzotriazole-l-methanamine, is a metal scavenger in liquid state at room temperature (at 25 °C) and having melting point of -62 °C, procured from Vanderbilt Chemicals, LLC.

[0151] MS-5 is CUV AN 826, chemical composition is 2,5-dimercapto-l,3,4- thiadiazole derivative, is a metal scavenger in liquid state at room temperature (at 25 oC) and having the melting point of-16 oC, procured from Vanderbilt Chemicals, LLC.

[0152] (F’) metal scavenger other than (F)

[0153] MS-2 is N,N'-(Hexane-l,6-diyl)bis[3-(3,5-di-tert-butyl-4- hydroxyphenyl) propanamide, a metal scavenger having the melting point of 158-162 °C and procured from TCI Chemicals.2737239917.1

[0154] MS-3 is Oxalylbis(azanediyl)]bis(ethane-2,l-diyl) Bis|3-(3.5-di- / c / 7- butyl-4-hydroxyphenyl)propanoate, a metal scavenger having the melting point of 178- 182 °C and procured from TCI Chemicals.

[0155] As shown in Table 1 and Table 2, in examples 1 and 2, when the low melting point (less than 100 °C) antioxidants ( AO-1 and AO-2) were used, lower BLT (below 30 microns) and lower TR (less than 10.0 mm2K / W) was observed, whereas, as shown in comparative examples 1 and 2, when the high melting point (more than 100 °C) antioxidants (AO-3 and AO-4) were used, higher BLT (more than 150 microns) and higher TR (more than 30.0 mm2K / W) was observed.

[0156] As shown in Table 1 and Table 2, in examples 3, 4, 5 and 6, when the low melting point (less than 100 °C) metal scavengers (MS-1, MS-4 and MS-5) were used, lower BLT (below 30 microns) and lower TR (less than 10 mm2K / W) was observed, whereas, as shown in comparative examples 3 and 4, when the high melting point (more than 100 °C) metal scavengers (MS-2 and MS-3) were used, higher BLT (more than 80 microns) and higher TR (more than 13.0 mm2K / W) was observed.

[0157] As shown in Table 3, upon aging the compositions at 150 °C for 1000 h on aluminum and copper substrates, examples 3,5 and 6 were maintaining their thermal resistance (TR) below 15.0 mm2K / W. Therefore, the composition after aging-treatment of examples 3, 5 and 6 showed excellent stability. On the other hand, the composition after aging-treatment of comparative example 3 became powdery. Therefore, the composition after aging-treatment of comparative example 3 does not have excellent stability.

[0158] As shown in Table 4, upon aging the compositions at 150 °C for 1000 h on aluminum substrate and on copper substrate, examples 3, 5 and 6 were maintaining their viscosity of 1300 Pa s or less. Therefore, the composition after aging-treatment of examples 3, 5 and 6 showed excellent wettability.

[0159] As shown in Table 5, upon aging, the composition comprising the metal scavenger having melting point less than 100°C, examples 3, 4, 5 and 6 showed excellent spreadability.2837239917.1

Claims

1. Claims:

1. A silicone thermal conductive composition comprising:(A) 1 to 5 weight percent of a silicone wax;(B) a thermally conductive filler;(C) 0.5 to 6 weight percent of a wetting agent;(D) an antioxidant having melting point not more than 100°C;(E) 0 to 3 weight percent of an optional additive other than (F); and(F) optionally a metal scavenger having melting point not more than 100 °C; wherein the silicone thermal conductive composition does not comprise a metal scavenger having melting point more than 100 °C.

2. The silicone thermal conductive composition according to claim 1, wherein the component (A) is an alky lated poly dimethylsiloxane.

3. The silicone thermal conductive composition according to claim 1 or 2, wherein the component (C) is a hydrolyzable organopolysiloxane (1) represented by the formula (I-i):(Formula I-i) or a hydrolysable polyorganosiloxane represented by the formula (I-ii):2937239917.1(Formula I-ii).

4. The silicone thermal conductive composition according to any of claims 1 to 3, wherein the component (D) is selected from hindered phenols, thioethers, and phosphites and / or a combination thereof.

5. The silicone thermal conductive composition according to any of claims 1 to 4, wherein the component (D) is selected from the group consisting of didodecyl 3,3 ’-thiodipropionate, octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate, and a combination thereof.

6. The silicone thermal conductive composition according to any of claims 1 to 5, wherein the component (D) is present in an amount of up to 5 weight percent based on the total weight of the composition.

7. The silicone thermal conductive composition according to any of claims 1 to 6, wherein the component (F) is selected from the group consisting of 5-methyl- IH-benzotriazole, N, N-bis(2-ethylhexyl)-4-methyl-lH-benzotriazole-l-methanamine, 2.5-dimercapto-l,3,4-thiadiazole, and a combination thereof.

8. The silicone thermal conductive composition according to any of claims 1 to 7, wherein the component (F) is present in an amount of up to 5 wt % based on the total weight of composition.

9. The silicone thermal conductive composition according to any of claims 1 to 8, wherein the component (B) is a metal oxide or a non-oxide filler.

10. The silicone thermal conductive composition according to claim 1 or 8, wherein the component (B) is a metal oxide, and the metal oxide filler is selected from the group consisting of alumina, magnesia, ceria, hafnia, lanthanum oxide, neodymium oxide, samaria. praseodymium oxide, thoria, urania, yttria, zinc oxide, zirconia, and a combination thereof.3037239917.

111. The silicone thermal conductive composition according to any of claims 1 to 8, wherein the component (B) is a non-oxide filler, and the non-oxide filler is selected from the group consisting of aluminum, metal boride, a metal carbide, a metal nitride, a metal silicide, carbon black, graphite, expanded graphite, carbon fiber, diamond, carbon nanotubes, graphite fiber, and a combination thereof.

12. The silicone thermal conductive composition according to any of claims 1 to 8, wherein the component (B) is selected from the group consisting of a zinc oxide, aluminum filler, and a combination thereof.

13. The silicone thermal conductive composition according to any of claims 1 to 12, wherein the particle size of the component (B) is from 0.01 pm to 500 pm.

14. The silicone thermal conductive composition according to any of claims 1 to 13, wherein the component (B) is present in an amount of from 80 weight percent to 99 weight percent based on the total weight of the composition.

15. The silicone thermal conductive composition according to any of claims 1 to 14, wherein the component (E) is selected from the group consisting of flame retardants, crosslinking agents, viscosits’ modifiers, thermal stabilizers, colorants, and a combination thereof.

16. The silicone thermal conductive composition according to any of claims1 to 15, wherein the component (E) is a carbosilane represented by the formula:wherein n is a number of 10 to 200.

17. The silicone thermal conductive composition according to any of claims 1 to 16, wherein the composition has a thermal resistance <10.0 mm2K / W.

18. The silicone thermal conductive composition according to any of claims 1 to 17. wherein when the composition has a thermal resistance <15.0 mm2K / W after aging-treatment at 150°C for lOOOh on aluminum substrate or on copper substrate.3137239917.

119. The silicone thermal conductive composition according to any of claims 1 to 18, wherein the composition has a viscosity of 1300Pa s or less after agingtreatment at 150°C for 1000 hours on aluminum substrate or on copper substrate, wherein the viscosity7of the composition is measured using Rheometer at 60 °C at shear rate of 2 s'1with 0.3 mm gap with parallel plate.

20. The silicone thermal conductive composition according to any of claims 1 to 19. wherein the composition has a bond line thickness < 50 microns.

21. An electronics package structure comprising the silicone thermal conductive composition according to any of claims 1 to 20, a heat generating component and one or more heat dissipating components, wherein the silicone thermal conductive composition provides a thermal connection between the heat generating component and the one or more heat dissipating components, and wherein the composition has a bond line thickness <50 microns.3237239917.1

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