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

Abstract

The thermally conductive silicone composition comprises (A) 100 parts by weight of an alkenyl group-containing organopolysiloxane; and (B) a mixture of components (B1) and (B2), where component (B1) is an organosilicon compound of 1 to 100 silicon atoms, containing at least one phenylene structure and at least one silicon-bonded hydrogen atom per molecule, and component (B2) is an organohydrogenpolysiloxane containing an average of 2 to 4 silicon-bonded hydrogen atoms per molecule, having a viscosity of 1 to 1,000 mPa·s at 25°C, but containing no phenylene structures in the molecule. The thermally conductive silicone composition further comprises (C) 400 to 3,500 parts by weight of a thermally conductive filler, (D) a siloxane macromonomer, and (E) a catalytic amount of a hydrosilylation reaction catalyst. A thermally conductive member comprising the thermally conductive silicone composition is also provided.

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This application claims priority to and all benefits of U.S. Provisional Patent Application No. 63 / 435,019, filed December 23, 2022, the contents of which are incorporated herein by reference.

[0002] The present invention relates to a thermally conductive silicone composition that has high thermal conductivity, excellent adhesion even to poorly adhesive substrates (e.g., aluminum die-cast materials), and remains flexible even after prolonged heating. Furthermore, the composition can also be used as a solventless thermally conductive silicone composition that can be cured at room temperature. [Background technology]

[0003] In recent years, with the increasing density and integration of hybrid ICs and printed wiring boards equipped with transistors, ICs, memory elements, and other electronic components, and the increasing capacity of secondary batteries (cell type), thermally conductive silicone compositions comprising an organopolysiloxane and a thermally conductive filler, such as aluminum oxide powder and zinc oxide powder, have been widely used to efficiently dissipate heat generated by electronic components, batteries, and other electronic and electrical devices. In particular, thermally conductive silicone compositions filled with a large amount of thermally conductive filler have been proposed to accommodate high heat dissipation requirements.

[0004] Conventional thermally conductive silicone compositions with high thermal conductivity can be achieved by treating the surface of a thermally conductive filler with a hydrolyzable silane having a long-chain alkyl group, thereby imparting flexibility and heat-resistant mechanical properties to the molded article. This reduces the increase in viscosity, even when the thermally conductive silicone composition is highly filled with a thermally conductive inorganic filler, thereby improving its moldability and processability.

[0005] However, although these thermally conductive silicone compositions can achieve a certain degree of viscosity reduction and moldability improvement, their fluidity is insufficient. Thus, it is difficult to precisely apply them to the highly refined structures of electrical and electronic materials, and gaps may occur between electronic components that need to dissipate heat, which may generate latent heat and prevent sufficient heat dissipation. Furthermore, when these electronic components require repairability, such as positioning and circuit rearrangement, the thermally conductive cured product of conventional thermally conductive silicone compositions is likely to adhere to the components. Therefore, it is difficult to peel the thermally conductive cured product from the components without leaving residue, which can reduce production yield and hinder the repair or reuse of electronic and electrical devices such as electronic components and batteries. Summary of the Invention

[0006] A thermally conductive silicone composition is disclosed. The thermally conductive silicone composition comprises (A) 100 parts by weight of an alkenyl-containing organopolysiloxane having a viscosity of 10 to 100,000 mPa·s at 25°C. The thermally conductive silicone composition also comprises (B) a mixture of components (B1) and (B2). Component (B1) is an organosilicon compound of 1 to 100 silicon atoms, containing at least one phenylene structure and at least one silicon-bonded hydrogen atom per molecule, and component (B2) is an organohydrogenpolysiloxane containing an average of 2 to 4 silicon-bonded hydrogen atoms per molecule, having a viscosity of 1 to 1,000 mPa·s at 25°C, but not containing a phenylene structure in the molecule. The total amount of silicon-bonded hydrogen atoms in component (B) is 0.5 to 1.1 moles per mole of alkenyl groups in component (A), and the molar ratio of silicon-bonded hydrogen atoms in component (B2) to component (B1) is 0.1 to 1.0. The thermally conductive silicone composition comprises (C) 400 to 3,500 parts by weight of a thermally conductive filler, and (D) a siloxane macromonomer represented by formula (I) or formula (II): R 1 R 2 R 3 Si-[(CH2) n1 (Me2SiO) m1 ]r -[O-(Me2SiO) m3 ] p -(Me2Si) o (CH2) n2 (Me2SiO) m2 -(CH2) n3 -Si(OR 4 3)3(I) where each Me is a methyl group and R 1 , R 2 , and R 3 are independently an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 4 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, or -(OSiR 7 R 8 R 9 ) (where R 7 , R 8 , and R 9 are each independently selected from alkyl groups having 1 to 4 carbon atoms; R 4 is an alkyl group having 1 to 4 carbon atoms, n1, n2, m1, m3, and o are integers of 1 to 200, m2, n3, r, and p are integers of 0 to 200, and r and p are not simultaneously 0; (R 5 O)3Si-[(CH2) n1 (Me2SiO) m1 ] r -(CH2) n4 -[O-(Me2SiO)m3] p -(Me2Si) o -(CH2) n2 -(Me2SiO) m2 -(CH2) n3 -Si(OR 6 )3(II) In the formula, R 5 and R 6 is an alkyl group having 1 to 4 carbon atoms, n1, m1, m3, o, and n2 are integers from 1 to 200, and n3, n4, m2, r, and p are integers from 0 to 200, provided that r and p are not simultaneously 0. Finally, the thermally conductive silicone composition includes (E) a catalytic amount of a hydrosilylation reaction catalyst.

[0007] A thermally conductive member comprising the thermally conductive silicone composition is also provided, along with a heat dissipation structure comprising the thermally conductive member. [Problem to be solved by the invention]

[0008] Conventionally, heat-generating components such as power transistors and thyristors are exposed to heat that deteriorates their performance, and therefore measures have been taken to dissipate the heat and release it into the metal housing of the equipment by installing a heat sink during installation.

[0009] In recent years, reactors have become increasingly necessary in power control units for hybrid vehicles, electric vehicles, and fuel cell vehicles in order to boost battery voltage and apply it to the motor. Furthermore, as power control units become smaller, reactors, which are one of their components, must also be made smaller, and their internal structures have become increasingly smaller and more complex in recent years.

[0010] Furthermore, because the temperature inside the reactor is high, a high heat dissipation performance of at least 0.5 W / mK is required. By filling the reactor directly with heat dissipation material, it is possible to increase the heat dissipation area from the entire reactor.

[0011] Therefore, potting properties and adhesion to the outer case are important. In particular, if adhesion to the case is insufficient, peeling occurs during subsequent use, resulting in a significant decrease in heat dissipation. Considering its formability and cost, aluminum die-cast is often used as the material for the outer case. However, aluminum die-cast is a substrate or adherend for which it is difficult to obtain adhesion.

[0012] Therefore, it is important to develop products that exhibit high adhesive strength and cohesive failure rates. [Means for solving the problem]

[0013] After thorough investigation, the inventors have found that (A) 100 parts by mass of an alkenyl group-containing organopolysiloxane having a viscosity of 10 to 100,000 mPa s at 25°C; (B) Components (B1) and (B2): (B1) an organosilicon compound having 1 to 100 silicon atoms and containing at least one phenylene structure and at least one silicon-bonded hydrogen atom per molecule; and (B2) A mixture of organohydrogenpolysiloxanes containing an average of 2 to 4 silicon-bonded hydrogen atoms per molecule, having a viscosity of 1 to 1,000 mPa·s at 25°C, and not containing a phenylene structure in the molecule, a mixture in which the total amount of silicon-bonded hydrogen atoms in component (B) is 0.5 to 1.1 moles per mole of alkenyl groups contained in component (A), and the molar ratio of silicon-bonded hydrogen atoms in component (B1) to component (B2) is 0.1 to 1.0; (C) 400 to 3,500 parts by mass of a thermally conductive filler; (D) a siloxane macromonomer represented according to formula (I) or formula (II): R 1 R 2 R 3 Si-[(CH2) n1 (Me2SiO) m1 ] r -[O-(Me2SiO) m3 ] p -(Me2Si) o (CH2) n2 (Me2SiO) m2 -CH2) n3 -Si(OR 4 3)3(I) where each Me is a methyl group and R 1 , R 2 , and R 3 are independently an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 4 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, or-(OSiR 7 R 8 R 9 ) (where R 7 , R 8 , and R 9are each independently selected from alkyl groups having 1 to 4 carbon atoms; R 4 is an alkyl group having 1 to 4 carbon atoms, n1, n2, m1, m3, and o are integers of 1 to 200, m2, n3, r, and p are integers of 0 to 200, and r and p are not simultaneously 0; (R 5 O)3Si-[(CH2) n1 (Me2SiO) m1 ] r -(CH2) n4 -[O-(Me2SiO)m3] p -(Me2Si) o -(CH2) n2 -Me2SiO) m2 -(CH2) n3 -Si(OR 6 )3(II) In the formula, R 5 and R 6 is an alkyl group having 1 to 4 carbon atoms, n1, m1, m3, o, and n2 are integers of 1 to 200, n3, n4, m2, r, and p are integers of 0 to 200, and r and p are not simultaneously 0; and (E) a catalytic amount of a hydrosilylation reaction catalyst; It has been found that the above problems can be solved by a composition comprising: [Effects of the Invention]

[0014] The thermally conductive silicone composition of the present invention has excellent thermal conductivity and excellent adhesion to a variety of substrates, including those known to have poor adhesion, such as die-cast aluminum, even after curing. Furthermore, the thermally conductive silicone composition after curing maintains flexibility even after prolonged exposure to high temperatures. Furthermore, the thermally conductive silicone composition can be formulated as a solventless composition and can be cured at room temperature. DETAILED DESCRIPTION OF THE INVENTION

[0015] The present disclosure provides thermally conductive silicone compositions ("the compositions"). The compositions and cured products have excellent physical properties, such as thermal conductivity and adhesion to a wide variety of substrates, including those known to have poor adhesive properties. As such, the compositions are particularly well suited for use in or as thermally conductive members and / or heat-dissipating structures. However, the end uses of the compositions and cured products formed therefrom are not particularly limited.

[0016] The composition comprises (A) an alkenyl-containing organopolysiloxane having a viscosity of 10 to 100,000 mPa·s at 25° C. In some specific examples, component (A) has a viscosity in the range of 10 to 10,000, alternatively 10 to 9,000, alternatively 10 to 8,000, alternatively 10 to 7,000, alternatively 10 to 6,000, alternatively 10 to 5,000, alternatively 10 to 4,000, alternatively 10 to 3,000, alternatively 10 to 2,000, or alternatively 10 to 1,000 mPa·s at 25° C. Viscosity can be measured at 25° C. via a Brookfield LV DV-E viscometer equipped with a spindle appropriately selected for the viscosity of the substantially linear polyorganopolysiloxane, i.e., RV-1 to RV-7.

[0017] As will be appreciated by those skilled in the art, organopolysiloxanes comprise inorganic silicon-oxygen-silicon groups (i.e., -Si-O-Si-) with organosilicon and / or organic side groups bonded to the silicon atoms in the M, D, and / or Q siloxy units. Organopolysiloxanes are typically characterized by the number, type, and / or proportion of [M], [D], [T], and / or [Q] units / siloxy groups, each unit / siloxy group representing a structural unit of an individual functional group present in the organopolysiloxane resin. Specifically, [M] is a group having the general formula R"SiO 1 / 2 [D] represents a monofunctional unit of the general formula R''SiO 2 / 2 [T] represents a difunctional unit of the general formula R''SiO 3 / 2 [Q] represents a trifunctional unit of the general formula SiO 4 / 2which represent tetrafunctional units of the following general structural moiety:

[0018] [ka] is shown by

[0019] In these general structural moieties, each R" is independently a monovalent or polyvalent substituent. As is understood in the art, the specific substituents suitable for each R" are not particularly limited (e.g., they can be monoatomic or polyatomic, organic or inorganic, straight or branched chain, substituted or unsubstituted, aromatic, aliphatic, saturated or unsaturated, etc., as well as various combinations thereof).

[0020] Those skilled in the art understand how the [M], [D], [T], and [Q] units and their relative proportions (i.e., mole fractions) influence and control the structure of a siloxane, and polysiloxanes can generally be monomeric, polymeric, oligomeric, linear, branched, cyclic, and / or resinous, depending on the selection of [M], [D], [T], and / or [Q] units therein. For example, [T] and / or [Q] units are present in organopolysiloxane resins, but linear organopolysiloxanes typically do not contain such [T] and / or [Q] units.

[0021] In certain embodiments, component (A) is a free-form Q unit. In these or other embodiments, component (A) does not contain both T and Q units. Specifically, component (A) is typically linear. The alkenyl groups are silicon-bonded and can be present at terminal positions (i.e., one or more M units) and / or pendant positions (i.e., one or more D units).

[0022] For example, component (A) may have the average formula: R a’ SiO (4-a’) / 2 wherein each R is independently selected from a substituted or unsubstituted hydrocarbyl group, provided that at least two of the R are independently alkenyl groups, and the subscript a' is selected such that 1.9≦a'≦2.2.

[0023] Generally, suitable hydrocarbyl groups for R can be independently linear, branched, cyclic, or a combination thereof. Cyclic hydrocarbyl groups include aryl groups and saturated or non-conjugated cyclic groups. Cyclic hydrocarbyl groups can independently be monocyclic or polycyclic. Linear and branched hydrocarbyl groups can independently be saturated or unsaturated. An example of a combination of linear and cyclic hydrocarbyl groups is an aralkyl group. Common examples of hydrocarbyl groups include alkyl groups, aryl groups, alkenyl groups, halocarbon groups, etc., as well as derivatives, variants, and combinations thereof. Examples of suitable alkyl groups include methyl, ethyl, propyl (e.g., isopropyl and / or n-propyl), butyl (e.g., isobutyl, n-butyl, tert-butyl, and / or sec-butyl), pentyl (e.g., isopentyl, neopentyl, and / or tert-pentyl), hexyl, hexadecyl, octadecyl, and branched saturated hydrocarbon groups having 6 to 18 carbon atoms. Examples of suitable non-conjugated cyclic groups include cyclobutyl, cyclohexyl, and cycloheptyl groups. Examples of suitable aryl groups include phenyl, tolyl, xylyl, naphthyl, benzyl, and dimethylphenyl. Examples of suitable alkenyl groups include vinyl, allyl, propenyl, isopropenyl, butenyl, isobutenyl, pentenyl, heptenyl, hexenyl, octenyl, hexadecenyl, octadecenyl, and cyclohexenyl groups. Examples of suitable monovalent halogenated hydrocarbon groups (i.e., halocarbon groups) include halogenated alkyl groups, aryl groups, and combinations thereof. Examples of halogenated alkyl groups include the alkyl groups described above in which one or more hydrogen atoms have been replaced with halogen atoms such as F or Cl.Specific examples of halogenated alkyl groups include fluoromethyl, 2-fluoropropyl, 3,3,3-trifluoropropyl, 4,4,4-trifluorobutyl, 4,4,4,3,3-pentafluorobutyl, 5,5,5,4,4,3,3-heptafluoropentyl, 6,6,6,5,5,4,4,3,3-nonafluorohexyl, and 8,8,8,7,7-pentafluorooctyl, 2,2-difluorocyclopropyl, 2,3-difluorocyclobutyl, 3,4-difluorocyclohexyl, and 3,4-difluoro-5-methylcycloheptyl, chloromethyl, chloropropyl, 2-dichlorocyclopropyl, and 2,3-dichlorocyclopentyl groups, and derivatives thereof. Examples of halogenated aryl groups include the aryl groups described above, in which one or more hydrogen atoms are replaced with halogen atoms such as F or Cl. Specific examples of halogenated aryl groups include chlorobenzyl and fluorobenzyl groups.

[0024] In certain embodiments, each R is independently selected from alkyl groups having 1 to 32, alternatively 1 to 28, alternatively 1 to 24, alternatively 1 to 20, alternatively 1 to 16, alternatively 1 to 12, alternatively 1 to 8, alternatively 1 to 4, alternatively 1 carbon atoms, and ethylenically unsaturated groups (i.e., alkenyl and / or alkynyl groups) having 2 to 32, alternatively 2 to 28, alternatively 2 to 24, alternatively 2 to 20, alternatively 2 to 16, alternatively 2 to 12, alternatively 2 to 8, alternatively 2 to 4, alternatively 2 carbon atoms.

[0025] "Alkenyl" refers to an acyclic, branched, or unbranched monovalent hydrocarbon group having one or more carbon-carbon double bonds. Specific examples include vinyl, allyl, hexenyl, and octenyl groups. Examples of ethylenically unsaturated groups include CH2=CH-, CH2=CHCH2-, CH2=CH(CH2)4-, CH2=CH(CH2)6-, CH2=C(CH3)CH2-, HC=C(CH3)-, HC=C(CH3)-, HC=C(CH3)CH2-, HC=CHCH2CH2-, and HC=CHCH2CH2CH2-. Typically, when R is an ethylenically unsaturated group, the ethylenic unsaturation is at the terminal of R. As understood in the art, ethylenic unsaturation can be referred to as aliphatic unsaturation.

[0026] (A) When the organopolysiloxane is substantially linear, or alternatively linear, the at least two aliphatically unsaturated groups may be bonded to the silicon atom at pendant positions, terminal positions, or both pendant and terminal positions.

[0027] When the (A) organopolysiloxane is a substantially linear polyorganosiloxane, the (B) organopolysiloxane may be a dimethylpolysiloxane capped at both molecular ends with dimethylvinylsiloxy groups, a methylphenylpolysiloxane capped at both molecular ends with dimethylvinylsiloxy groups, a copolymer of a methylphenylsiloxane and a dimethylsiloxane capped at both molecular ends with dimethylvinylsiloxy groups, a copolymer of a methylvinylsiloxane and a methylphenylsiloxane capped at both molecular ends with dimethylvinylsiloxy groups, a methylvinylsiloxane capped at both molecular ends with dimethylvinylsiloxy groups, or a methylvinylsiloxane capped at both molecular ends with dimethylvinylsiloxy groups. copolymers of methylvinylsiloxane, methylphenylsiloxane, and dimethylsiloxane, both of which are end-capped with dimethylvinylsiloxy groups; copolymers of methylvinylsiloxane and methylphenylsiloxane, both of which are end-capped with trimethylsiloxy groups; copolymers of methylvinylsiloxane and diphenylsiloxane, both of which are end-capped with trimethylsiloxy groups; and copolymers of methylvinylsiloxane, methylphenylsiloxane, and dimethylsiloxane, both of which are end-capped with trimethylsiloxy groups.

[0028] In certain embodiments, component (A) is: i) dimethylvinylsiloxy-terminated polydimethylsiloxane; ii) dimethylvinylsiloxy-terminated poly(dimethylsiloxane / methylvinylsiloxane); iii) dimethylvinylsiloxy-terminated polymethylvinylsiloxane; iv) trimethylsiloxy-terminated poly(dimethylsiloxane / methylvinylsiloxane); v) trimethylsiloxy-terminated polymethylvinylsiloxane; vi) dimethylvinylsiloxy-terminated poly(dimethylsiloxane / methylvinylsiloxane), vii) dimethylvinylsiloxy-terminated poly(dimethylsiloxane / methylphenylsiloxane); viii) dimethylvinylsiloxy-terminated poly(dimethylsiloxane / diphenylsiloxane); ix) phenyl, methyl, vinyl-siloxy terminated polydimethylsiloxanes; x) dimethylhexenylsiloxy-terminated polydimethylsiloxane, xi) dimethylhexenylsiloxy-terminated poly(dimethylsiloxane / methylhexenylsiloxane); xii) dimethylhexenylsiloxy-terminated polymethylhexenylsiloxane; xiii) trimethylsiloxy-terminated poly(dimethylsiloxane / methylhexenylsiloxane); xiv) trimethylsiloxy-terminated polymethylhexenylsiloxane; xv) dimethylhexenylsiloxy-terminated poly(dimethylsiloxane / methylhexenylsiloxane), xvi) dimethylvinylsiloxy-terminated poly(dimethylsiloxane / methylhexenylsiloxane) and xvii) combinations of these is selected from the group consisting of:

[0029] Component (A) can contain one or more alkenyl group-containing organopolysiloxanes. The molecular structure of the alkenyl group-containing organopolysiloxane of component (A) is not particularly limited, and examples include linear, branched, cyclic, and three-dimensional network structures, as well as combinations thereof. Component (A) can contain only linear alkenyl group-containing organopolysiloxanes, only alkenyl group-containing organopolysiloxanes having a branched structure, or a mixture of linear organopolysiloxanes and alkenyl group-containing organopolysiloxanes having a branched structure.

[0030] The composition comprises component (A) in an amount of 100 parts by weight.

[0031] The composition also includes (B) a mixture of components (B1) and (B2). Typically, component (B) is a premix, i.e., components (B1) and (B2) are mixed to obtain component (B) before combining component (B) with the other components of the composition. However, in other embodiments, component (B) can be formed in situ by mixing components (B1) and (B2) in the presence of one or more other components of the composition.

[0032] Component (B1) is an organosilicon compound having 1 to 100 silicon atoms, alternatively 2 to 30 silicon atoms, and containing at least one phenylene structure and at least one silicon-bonded hydrogen atom (i.e., SiH group) per molecule. The term "phenylene structure" as used herein encompasses aromatic ring structures having a valence of 2 to 6, alternatively 2 to 4, such as phenylene, naphthalene, and anthracene structures. Component (B1) is effective in imparting adhesive properties to the composition. In this sense, component (B1) can be referred to as a tackifier.

[0033] Examples of component (B1) include organosilicon compounds having 1 to 100 silicon atoms, alternatively 2 to 30 silicon atoms, alternatively 2 to 20 silicon atoms, alternatively 4 to 10 silicon atoms. The organosilicon compound of component (B1) may be a linear or cyclic organosiloxane oligomer or organosilane having at least 1, typically 1 to 20, alternatively 2 to 10 SiH groups (i.e., silicon-bonded hydrogen atoms) per molecule, may have at least 1, typically 1 to 4 phenylene structures, and may further contain one or more functional groups including epoxy groups such as glycidoxy, alkoxysilyl groups such as trimethoxysilyl, triethoxysilyl, and methyldimethoxysilyl, ester, acrylic acid, methacrylic acid, carboxylic acid anhydride, isocyanate, amino, or amide groups.

[0034] In a specific embodiment, component (B1) has the following structure:

[0035] [ka] wherein each subscript n is independently an integer from 1 to 3, and each D 1 is independently selected from a divalent hydrocarbon group and a covalent bond. 1 When D is a covalent bond, only oxygen atoms are present between the phenylene moiety and the cyclic siloxane moiety. 1 is a covalent bond. In other embodiments, each D 1 is a divalent hydrocarbon group having 1 to 8, alternatively 1 to 7, alternatively 1 to 6, alternatively 1 to 5, alternatively 1 to 4, alternatively 1 to 3 carbon atoms.

[0036] Examples of organosilicon compounds suitable for component (B1) are illustrated below:

[0037] [ka]

[0038] [ka] In the formula, n is independently an integer of 1 to 4. In the above structure, any of the O(CH2)3 moieties bridging each phenylene moiety and each cyclic siloxane moiety can be substituted with, for example, O, OCH2, O(CH2)2, etc.

[0039] Further examples of component (B1) are:

[0040] [ka] In the formula, x is

[0041] [ka] is.

[0042] In the above examples, Y is any of the following groups:

[0043] [ka] In the formula, n is an integer of 1 to 4,

[0044] [ka] In the formula, R′ is

[0045] [ka] where R w and R x are each independently a substituted or unsubstituted monovalent hydrocarbon group; q is an integer from 1 to 50, alternatively from 1 to 20; h is an integer from 0 to 100, alternatively from 1 to 50; and R″ is

[0046] [ka] where R w and R x is as defined above, and y is an integer from 0 to 100, and Y′ is any of the following groups:

[0047] [ka] where n is an integer from 1 to 4, and

[0048] [ka] In the formula, R w , R x, q, and h are as defined above, and z is an integer from 1 to 10.

[0049] R w and R x Suitable optionally substituted monovalent hydrocarbon groups represented by include those groups described above for R. The hydrocarbyl groups described above for R w and / or R x may be substituted with an alkoxy, acryl, methacryl, acryloyl, methacryloyl, amino, or alkylamino group.

[0050] Additional examples of component (B1) include the above organosilicon compounds further containing alkoxysilyl groups such as trimethoxysilyl, triethoxysilyl, and methyldimethoxysilyl, as well as acrylic, methacrylic, ester, carboxylic anhydride, isocyanate, amino, and amide groups.

[0051] The silicon-bonded hydrogen atom content (SiH content) of the organosilicon compound of component (B1) is typically 0.001 to 0.01 mol / g, and more preferably 0.002 to 0.01 mol / g.

[0052] The organosilicon compound of component (B1) generally does not contain alkenyl groups. When an alkenyl-containing organosilicon compound is used as component (B1), it should be used in an amount such that the molar ratio of total SiH groups in the composition to total silicon-bonded alkenyl groups in the composition is 1.0 to 5.0, alternatively 1.2 to 4.0, alternatively 1.5 to 3.0.

[0053] Component (B2) is an organohydrogenpolysiloxane containing an average of 2 to 4 silicon-bonded hydrogen atoms per molecule and having a viscosity of 1 to 1,000 mPa·s at 25°C. Unlike component (B1), component (B2) does not contain a phenylene structure within the molecule. Component (B2) functions as a crosslinker or chain extender for component (A) when the SiH groups in the molecule undergo a hydrosilylation reaction or addition reaction with the silicon-bonded alkenyl groups of component (A). The organohydrogenpolysiloxane of component (B2) is typically linear.

[0054] In certain embodiments, component (B2) contains silicon-bonded hydrogen atoms only at its molecular terminals. In other words, in such embodiments, component (B2) does not contain silicon-bonded hydrogen atoms at pendant positions, i.e., silicon-bonded hydrogen atoms bonded to silicon atoms in D siloxy units. In other embodiments, component (B2) contains silicon-bonded hydrogen atoms only at pendant positions, i.e., silicon-bonded hydrogen atoms bonded to silicon atoms in D siloxy units. In other words, in such embodiments, component (B2) does not contain silicon-bonded hydrogen atoms at terminal positions, i.e., silicon-bonded hydrogen atoms bonded to silicon atoms in M ​​siloxy units. In yet other embodiments, component (B2) contains silicon-bonded hydrogen atoms at both pendant and terminal positions.

[0055] In a specific embodiment, component (B2) has the average unit formula: (HR 10 2SiO 1 / 2 )(R 10 2SiO 2 / 2 ) n’ (HR 10 2SiO 1 / 2 ), wherein each R 10 are independently selected hydrocarbyl groups, alternatively independently selected alkyl groups, and the subscript n' is selected to provide a viscosity of component (B2) at 25°C of 1 to 1,000 mPa·s, alternatively 10 to 500 mPa·s. In other embodiments, the linear organohydrogenpolysiloxane has the average unit formula: (R 103SiO 1 / 2 )(R 10 2SiO 2 / 2 ) x’ (HR 10 SiO 2 / 2 )y'(R 10 3SiO 1 / 2 ) wherein each R 10 is an independently selected hydrocarbyl group, alternatively an independently selected alkyl group; subscript y' is 2 to 4; and subscript x' is selected to provide a viscosity of component (B) at 25°C of 1 to 1,000 mPa·s, alternatively 10 to 500 mPa·s.

[0056] In another embodiment, component (B2) has the average formula: H(CH3)2SiO[(CH3)2SiO 2 / 2 ] n’ Si(CH3)2H In a different specific embodiment, component (B2) has the average formula: (CH3)3SiO[(CH3)2SiO 2 / 2 ] x’ (H(CH3)SiO 2 / 2 )y'OSi(CH3)3 where x' and y' are as defined above. Component (B2) may comprise a combination or two or more different organohydrogenpolysiloxanes that differ in at least one property, such as structure, molecular weight, degree of polymerization, viscosity, etc.

[0057] The total amount of silicon-bonded hydrogen atoms in component (B) (including those derived from both components (B1) and (B2)) is 0.5 to 1.1 mol, alternatively 0.6 to 1.1 mol, or alternatively 0.7 to 1.1 mol per mole of alkenyl groups in component (A). Furthermore, the molar ratio of silicon-bonded hydrogen atoms in component (B1) to silicon-bonded hydrogen atoms in component (B2) is 0.1 to 1.0, alternatively 0.10 to 0.75, or alternatively 0.15 to 0.60. If the conversion of component (B) or the molar ratio of SiH in (B1) to SiH in (B2) is outside this range, the flexibility of the composition after heating may be impaired or insufficient.

[0058] The composition further contains (C) 400 to 3,500 parts by mass of a thermally conductive filler.

[0059] The thermally conductive filler (C) is used to impart thermal conductivity to the composition and the thermally conductive member obtained by curing the composition. Such component (C) is typically at least one powder and / or fiber selected from the group consisting of pure metals, alloys, metal oxides, metal hydroxides, metal nitrides, metal carbides, metal silicides, carbon, soft magnetic alloys, and ferrites. Among these, metal powders, metal oxide powders, metal nitride powders, and carbon powders are most typical.

[0060] All or a portion of the thermally conductive filler (C) is optionally, but typically, surface-treated with an alkoxysilane as component (G), which will be described later. Furthermore, powders and / or fibers treated with various surface treatment agents known as coupling agents can be used alone or together with component (G). Examples of surface treatment agents for treating the powders and / or fibers of component (C), in addition to component (G), include surfactants, other silane coupling agents, aluminum-based coupling agents, silicone-based surface treatment agents, etc.

[0061] Examples of pure metals include bismuth, lead, tin, antimony, indium, cadmium, zinc, silver, copper, nickel, aluminum, iron, and metallic silicon. Examples of alloys include alloys of two or more metals selected from the group consisting of bismuth, lead, tin, antimony, indium, cadmium, zinc, silver, aluminum, iron, and metallic silicon. Examples of metal oxides include alumina, zinc oxide, silicon oxide, magnesium oxide, beryllium oxide, chromium oxide, and titanium oxide. Examples of metal hydroxides include magnesium hydroxide, aluminum hydroxide, barium hydroxide, and calcium hydroxide. Examples of metal nitrides include boron nitride, aluminum nitride, and silicon nitride. Examples of metal carbides include silicon carbide, boron carbide, and titanium carbide. Examples of metal silicides include magnesium silicide, titanium silicide, zirconium silicide, tantalum silicide, niobium silicide, chromium silicide, tungsten silicide, and molybdenum silicide. Examples of carbon include diamond, graphite, fullerenes, carbon nanotubes, graphene, activated carbon, and amorphous carbon black. Examples of soft magnetic alloys include Fe-Si alloys, Fe-Al alloys, Fe-Si-Al alloys, Fe-Si-Cr alloys, Fe-Ni alloys, Fe-Ni-Co alloys, Fe-Ni-Mo alloys, Fe-Co alloys, Fe-Si-Al-Cr alloys, Fe-Si-B alloys, and Fe-Si-Co-B alloys. Examples of ferrites include Mn-Zn ferrite, Mn-Mg-Zn ferrite, Mg-Cu-Zn ferrite, Ni-Zn ferrite, Ni-Cu-Zn ferrite, and Cu-Zn ferrite.

[0062] In a specific embodiment, component (C) comprises silver powder, aluminum powder, aluminum oxide powder, zinc oxide powder, aluminum nitride powder, or graphite. When the composition requires electrical insulation, a metal oxide powder or a metal nitride powder is preferably used, and aluminum oxide powder, zinc oxide powder, or aluminum nitride powder is particularly preferably used.

[0063] The shape of component (C) is not particularly limited, and examples thereof include spherical, acicular, discoid, rod-like, and irregular shapes, but is typically spherical or irregular. The average particle size of component (C) is not particularly limited, but is typically in the range of 0.01 to 100 μm, alternatively in the range of 0.01 to 50 μm.

[0064] In a specific embodiment, component (C) comprises (C1) layered boron nitride powder having an average particle size of 0.1 to 30 μm, (C2) granular boron nitride powder having an average particle size of 0.1 to 50 μm, (C3) spherical and / or crushed aluminum oxide powder having an average particle size of 0.01 to 50 μm, or (C4) spherical and / or crushed graphite having an average particle size of 0.01 to 50 μm, or a combination of two or more of these. A mixture of two or more types of spherical and / or crushed aluminum oxide powder having an average particle size of 0.01 to 50 μm is most typical. The combination of aluminum oxide powder having a large particle size and aluminum oxide powder having a small particle size in a ratio according to the closest packing theoretical distribution curve can, among other things, improve packing efficiency, reduce viscosity, and increase thermal conductivity.

[0065] The content of component (C) in the composition is in the range of 400 to 3,500 parts by mass, alternatively 400 to 3,000 parts by mass, per 100 parts by mass of component (A). This is because if the content of component (C) is below the lower limit of the aforementioned range, the thermal conductivity of the resulting composition tends to be insufficient, and if the content of component (C) is above the upper limit of the aforementioned range, the viscosity of the resulting composition increases significantly, even when component (G) is blended or used for surface treatment of component (C), and therefore, the handleability, gap-filling properties, etc. tend to deteriorate.

[0066] The composition further comprises (D) a siloxane macromonomer represented by the following formula (I) and / or formula (II): Formula (I) is as follows: R 1 R 2 R3 Si-[(CH2) n1 (Me2SiO) m1 ] r -[O-(Me2SiO) m3 ] p -(Me2Si) o (CH2) n2 (Me2SiO) m2 -CH2) n3 -Si(OR 4 3)3(I) where each Me is a methyl group and R 1 , R 2 , and R 3 are independently an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 4 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, or -(OSiR 7 R 8 R 9 ) (where R 7 , R 8 , and R 9 are each independently selected from alkyl groups having 1 to 4 carbon atoms; R 4 is an alkyl group having 1 to 4 carbon atoms, n1, n2, m1, m3, and o are integers of 1 to 200, m2, n3, r, and p are integers of 0 to 200, and r and p are not simultaneously 0.

[0067] The formula (II) of component (D) is as follows: (R 5 O)3Si-[(CH2) n1 (Me2SiO) m1 ] r -(CH2) n4 -[O-(Me2SiO)m3] p -(Me2Si) o -(CH2) n2 -Me2SiO) m2 -(CH2) n3 -Si(OR 6 )3(II) In the formula, R 5 and R 6is an alkyl group having 1 to 4 carbon atoms, n1, m1, m3, o, and n2 are integers of 1 to 200, n3, n4, m2, r, and p are integers of 0 to 200, and r and p are not simultaneously 0.

[0068] In certain embodiments, component (D) can be considered a surface treatment agent. For example, without wishing to be bound by theory, it is believed that the compound of formula (I) can easily bond to the surface of the filler, such as component (C), by chemical and / or physical bonding, and can provide the filler with better affinity for the organopolysiloxane, thereby making the composition flowable and having good processability, even when a large amount of filler is loaded.

[0069] Specific examples of compounds represented by formula (I) include: ViMe2SiO(Me2SiO) 27 SiMe2-(CH2)2-(Me2SiO)2-(CH2)2-Si(OMe)3, ViMe2SiO(Me2SiO) 58 SiMe2-(CH2)2-(Me2SiO)2-(CH2)2-Si(OMe)3, ViMe2SiO(Me2SiO) 125 SiMe2-(CH2)2-(Me2SiO)2-(CH2)2-Si(OMe)3, · (OSiMe3)2SiMe-(CH2)2-Me2SiO(Me2SiO) 58 SiMe2-(CH2)2-(Me2SiO)2-(CH2)2-Si(OMe)3, C8H 17 -(Me2SiO) 25 SiMe2-(CH2)6-Si(OMe)3, C8H 17 -(Me2SiO) 45 SiMe2-(CH2)6-Si(OMe)3, · (C8H 17 -(Me2SiO) 65 SiMe2-(CH2)6-Si(OMe)3), and · (C8H 17 -(Me2SiO) 115 SiMe2-(CH2)6-Si(OMe)3) These include, but are not limited to:

[0070] Specific examples of compounds represented by formula (II) include: · (OMe)3Si-(CH2)2-(Me2SiO)2-(CH2)2-Me2SiO(Me2SiO) 27 SiMe2-(CH2)2-(Me2SiO)2-(CH2)2-Si(OMe)3, · (OMe)3Si-(CH2)2-(Me2SiO)2-(CH2)2-Me2SiO(Me2SiO) 58 SiMe2-(CH2)2-(Me2SiO)2-(CH2)2-Si(OMe)3, · (OMe)3Si-(CH2)2-(Me2SiO)2-(CH2)2-Me2SiO(Me2SiO) 125 SiMe2-(CH2)2-(Me2SiO)2-(CH2)2-Si(OMe)3, (OMe)3Si-(CH2)6-(Me2SiO) 25 SiMe2-(CH2)6-Si(OMe)3, (OMe)3Si-(CH2)6-(Me2SiO) 45 SiMe2-(CH2)6-Si(OMe)3, (OMe)3Si-(CH2)6-(Me2SiO) 65 SiMe2-(CH2)6-Si(OMe)3, and (OMe)3Si-(CH2)6-(Me2SiO) 115 Examples include, but are not limited to, SiMe2-(CH2)6-Si(OMe)3.

[0071] In certain embodiments, component (D) comprises, or alternatively consists of, compounds of formula (I), excluding compounds of formula (II). In other embodiments, component (D) comprises, or alternatively consists of compounds of formula (II), excluding compounds of formula (I). In yet other embodiments, component (D) comprises a blend of compounds of formula (I) and formula (II). In such embodiments, i.e., embodiments in which a blend is used, the molar ratio of compounds of formula (I) to compounds of formula (II) ((I) / (II)) is from 2 to 15, alternatively from 6 to 12. Furthermore, component (D) can comprise a combination of two or more different compounds falling within the scope of formula (I), the scope of formula (II), or both.

[0072] Component (D) provides desirable processability for the composition, even though the composition contains a large amount of thermally conductive filler (C). Because the compounds of formulas (I) and (II) have terminal alkoxy groups, component (D) can react with hydroxyl groups on the surface of the thermally conductive filler (C). The amount of component (D) in the composition is 0.01 to 20 wt %, alternatively 0.1 to 10 wt %, based on the total weight of the composition. In a specific embodiment, the amount of component (D) in the composition is 0.005 to 10 parts by weight, based on 100 parts by weight of component (A).

[0073] The composition further comprises (E) a hydrosilylation catalyst. Those skilled in the art can easily determine the amount of catalyst based on the number of reactive groups in the other components of the composition and other reaction parameters. The hydrosilylation catalyst (E) is not limited and may be any known hydrosilylation catalyst for catalyzing a hydrosilylation reaction. A combination of different hydrosilylation catalysts may be used as component (E).

[0074] The hydrosilylation catalyst may be in or on a solid support. Examples of supports include activated carbon, silica, silica alumina, alumina, zeolites, and other inorganic powders / particles (e.g., sodium sulfate). The (E) hydrosilylation catalyst may be disposed in a vehicle, for example, in a solvent that solubilizes the (E) hydrosilylation catalyst, or alternatively, in a vehicle that simply carries but does not solubilize the (E) hydrosilylation catalyst. Such vehicles are known in the art.

[0075] In specific embodiments, the (E) hydrosilylation catalyst comprises platinum. In these embodiments, the (E) hydrosilylation catalyst is exemplified by compounds such as platinum black, chloroplatinic acid, chloroplatinic acid hexahydrate, reaction products of chloroplatinic acid with monohydric alcohols, platinum bis(ethylacetoacetate), platinum bis(acetylacetonate), platinum chloride, and complexes of such compounds with olefins or organopolysiloxanes, as well as platinum compounds microencapsulated in matrices or core-shell compounds. Microencapsulated hydrosilylation catalysts and methods for their preparation are also known in the art, as exemplified by U.S. Pat. Nos. 4,766,176 and 5,017,654, which are incorporated herein by reference in their entireties.

[0076] Suitable platinum complexes with organopolysiloxanes for use as the hydrosilylation reaction catalyst (E) include 1,3-diethenyl-1,1,3,3-tetramethyldisiloxane, 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane, alkenylsiloxanes obtained by substituting a portion of the methyl groups of alkenylsiloxanes with ethyl groups or phenyl groups, and alkenylsiloxanes obtained by substituting a portion of the vinyl groups of these alkenylsiloxanes with allyl groups, hexenyl groups, etc. In particular, 1,3-divinyl-1,1,3,3-tetramethyldisiloxane is typically used due to the good stability of this platinum-alkenylsiloxane complex, and is generally added in the form of a complex alkenylsiloxane solution. These complexes can be microencapsulated in a resin matrix. Alternatively, the hydrosilylation catalyst (E) may comprise a 1,3-diethenyl-1,1,3,3-tetramethyldisiloxane platinum complex. The hydrosilylation catalyst (E) may be prepared by a method comprising reacting chloroplatinic acid with an aliphatically unsaturated organosilicon compound, such as divinyltetramethyldisiloxane, or an alkene-platinum-silyl complex.

[0077] The hydrosilylation catalyst (E) may also or alternatively be a photoactivatable hydrosilylation catalyst, which may initiate curing via irradiation and / or heat. The photoactivatable hydrosilylation catalyst may be any hydrosilylation catalyst capable of catalyzing a hydrosilylation reaction, particularly when exposed to radiation having a wavelength of 150 to 800 nanometers (nm).

[0078] Specific examples of photoactivatable hydrosilylation catalysts suitable for the hydrosilylation reaction catalyst include platinum(II) β-diketonate complexes, such as platinum(II) bis(2,4-pentanedioate), platinum(II) bis(2,4-hexanedioate), platinum(II) bis(2,4-heptanedioate), platinum(II) bis(1-phenyl-1,3-butanedioate, platinum(II) bis(1,3-diphenyl-1,3-propanedioate), platinum(II) bis(1,1,1,5, 5,5-hexafluoro-2,4-pentanedioate), (η-cyclopentadienyl)trialkylplatinum complexes such as (Cp)trimethylplatinum, (Cp)ethyldimethylplatinum, (Cp)triethylplatinum, (chloro-Cp)trimethylplatinum, and (trimethylsilyl-Cp)trimethylplatinum, where Cp represents cyclopentadienyl; triazene oxide-transition metal complexes such as [Pt[C6H5NNNOCH3]4, Pt[p-CN-C6H4NNNOCH6H 11 ]4, Pt[p-H3COC6H4NNNOC6H 11 ]4, Pt[p-CH3(CH2) x -C6H4NNNOCH3]4, 1,5-cyclooctadienePt[p-CN-C6H4NNNOC6H 11 ]2, 1,5-cyclooctadiene Pt[p-CH3O-C6H4NNNOCH3]2, [(C6H5)3P]3Rh[p-CN-C6H4NNNOC6H 11 ], and Pd[p-CH3(CH2) x -C6H4NNNOCH3]2, etc., where x is 1, 3, 5, 11, or 17; (σ-diolefin)(σ-aryl)platinum complexes, such as (η 4 -1,5-cyclooctadienyl)diphenylplatinum, (η 4 -1,3,5,7-cyclooctatetraenyl)diphenylplatinum, (η 4 -2,5-norborazienyl)diphenylplatinum, (η 4 -1,5-cyclooctadienyl)bis-(4-dimethylaminophenyl)platinum, (η 4 -1,5-cyclooctadienyl)bis-(4-acetylphenyl)platinum, and (η 4Typically, the photoactivatable hydrosilylation catalyst is a Pt(II) β-diketonate complex, and more typically, the catalyst is platinum(II) bis(2,4-pentanediatoate).

[0079] The hydrosilylation catalyst (E) is present in the composition in a catalytic amount, i.e., an amount or quantity sufficient to promote cure under the desired conditions. The hydrosilylation catalyst can be a single hydrosilylation catalyst or a mixture comprising two or more different hydrosilylation catalysts.

[0080] The catalytic amount of the hydrosilylation reaction catalyst (E) can be an amount that results in a metal atom content in the range of 0.01 to 500 ppm, 0.01 to 100 ppm, or 0.01 to 50 ppm by mass relative to the entire composition.

[0081] In certain embodiments, the composition further comprises (F) a heat resistance imparting agent to improve the heat resistance of the thermally conductive silicone composition and its cured product. Component (F) is not particularly limited, provided that it is selected to impart heat resistance to the composition and its cured product. Examples include metal oxides such as iron oxide, titanium oxide, cerium oxide, magnesium oxide, aluminum oxide, and zinc oxide; metal hydroxides such as cerium hydroxide; phthalocyanine compounds; carbon black; cerium silanolates; cerium fatty acid salts; and reaction products of organopolysiloxanes and cerium carboxylates. Typically, phthalocyanine compounds are used, such as additives selected from the group consisting of metal-free phthalocyanine compounds and metal-containing phthalocyanine compounds, as disclosed in JP 2014-503680 A. Among metal-containing phthalocyanine compounds, copper phthalocyanine compounds are the most typical. A specific, non-limiting example of a heat resistance additive is 29H,31H-phthalocyaninato(2-)-N29,N30,N31,N32 copper. Such phthalocyanine compounds are commercially available, for example, as STAN-TONE™ 40SP03 from PolyOne Corporation (Avon Lake, Ohio, USA).

[0082] A blend of different heat resistance agents may be used together as component (F). The amount of component (F) may range from 0.01 to 5.0% by weight of the total composition. It may range from 0.05 to 0.2% by weight, or from 0.07 to 0.1% by weight.

[0083] In certain embodiments, the composition further comprises (G) an alkoxysilane. The alkoxysilane has an alkyl group having 6 or more carbon atoms. For example, the alkyl group having 6 or more carbon atoms can be an alkyl group such as hexyl, octyl, dodecyl, tetradecyl, hexadecyl, or octadecyl, as well as an aralkyl group such as benzyl or phenylethyl. In other words, the aralkyl group is considered an alkyl group for the purposes of component (G). Alkyl groups containing 6 to 20 carbon atoms are particularly preferred. In the case of alkoxysilanes having alkyl groups with fewer than 6 carbon atoms, the viscosity of the composition may be insufficient. As a result, the viscosity of the composition may increase, and the desired flowability and gap-filling properties may not be achieved. Furthermore, when alkoxysilanes having alkyl groups with 20 or more carbon atoms are used, not only is industrial supply difficult, but compatibility may also decrease depending on the type of component (A).

[0084] In certain embodiments, component (G) is represented by the following structural formula: Y n Si(OR) 4-n In the formula, Y is an alkyl group having 6 to 18 carbon atoms, R is an alkyl group having 1 to 5 carbon atoms, and n is 1 or 2. Examples of OR groups include methoxy, ethoxy, propoxy, and butoxy groups.

[0085] Specific examples of alkoxysilanes suitable for component (G) include 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 Examples include Si(OC2H5)3.

[0086] The amount of component (G) is 0.1 to 2.0% by mass relative to component (C). If this amount is less than the lower limit of the aforementioned range, the viscosity-reducing effect of the composition may be insufficient. If the amount of component (G) exceeds the upper limit of the aforementioned range, the viscosity-reducing effect may saturate and the alkoxysilane may further separate, resulting in a decrease in the storage stability of the composition. When used, component (G) may comprise a combination or two or more different organopolysiloxane resins that differ in at least one property, such as structure, molecular weight, or number of monovalent groups bonded to silicon atoms.

[0087] In various embodiments, component (G) is blended in such a manner that component (C) is surface-treated with component (G). From the viewpoint of improving the fluidity and gap-filling ability of the present composition, it is desirable that at least a portion of component (C) is surface-treated with component (G). When component (G) is used as a surface treatment agent, its amount is typically 0.15 to 1.2% by mass, alternatively 0.2 to 1.0% by mass, relative to component (C).

[0088] The surface treatment method using component (G) is not particularly limited, but may include direct treatment of the thermally conductive filler, i.e., component (C), integral blending, dry concentrate, etc. Direct treatment methods include the dry method, slurry method, spray method, etc. Integral blending methods include the direct method and masterbatch method, etc. Among these, the dry method, slurry method, and direct method are frequently used. The total amounts of component (G) and component (C) may be premixed using a known mixing device, and the surface may be treated. The mixing device is not particularly limited, and examples thereof include a single-screw or twin-screw continuous mixer, a two-roll mill, a Ross mixer, a Hobart mixer, a dental mixer, a planetary mixer, a kneader mixer, and a Henschel mixer.

[0089] In a specific embodiment, component (C) is blended with both components (D) and (G) and surface treated, and then the surface-treated form of component (C) is combined with the other components of the composition. Component (C) may be blended incrementally with components (D) and (G), optionally in the presence of a portion of component (A).

[0090] In certain embodiments, the composition further comprises an adhesion promoter. Suitable adhesion promoters may include hydrocarbon oxysilanes such as alkoxysilanes, combinations of alkoxysilanes with hydroxy-functional polyorganosiloxanes, amino-functional silanes, epoxy-functional silanes, mercapto-functional silanes, or combinations thereof. Adhesion promoters are known in the art and may be represented by the formula: R 5 a R 6 b Si(OR 7 ) 4-(a+b) wherein each R 5 are independently a monovalent organic group having at least 3 carbon atoms, and R 6 contains at least one SiC-bonding substituent having an adhesion-promoting group such as an amino group, an epoxy group, a mercapto group, or an acrylate group, and each R 7 are independently monovalent organic groups (e.g., methyl, ethyl, propyl, butyl, etc.), the subscript a has a value ranging from 0 to 2, the subscript b is either 1 or 2, and the sum of (a+b) is 3 or less. In certain embodiments, the adhesion promoter comprises a partial condensate of the above-described silanes. In these or other embodiments, the adhesion promoter comprises a combination of an alkoxysilane and a hydroxy-functional polyorganosiloxane.

[0091] In some embodiments, the adhesion promoter comprises an unsaturated or epoxy-functional compound. In such embodiments, the adhesion promoter comprises an unsaturated or epoxy-functional alkoxysilane, such as a compound represented by formula (XIII): R 8 c Si(OR 9 ) (4-c)where subscript c is 1, 2, or 3; alternatively, subscript c can be or include 1. Each R 8 are independently a monovalent organic group, provided that at least one R 8 R is an unsaturated organic group or an epoxy-functional organic group. 8 Epoxy-functional organic groups of R are exemplified by 3-glycidoxypropyl and (epoxycyclohexyl)ethyl. 8 The unsaturated organic groups are exemplified by 3-methacryloyloxypropyl, 3-acryloyloxypropyl, and unsaturated monovalent hydrocarbon groups such as vinyl, allyl, hexenyl, undecylenyl, and the like. 9 are independently saturated hydrocarbon groups having 1 to 4 carbon atoms, alternatively 1 to 2 carbon atoms. 9 is exemplified by methyl, ethyl, propyl, and butyl.

[0092] Specific examples of suitable epoxy-functional alkoxysilanes include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, (epoxycyclohexyl)ethyldimethoxysilane, (epoxycyclohexyl)ethyldiethoxysilane, and combinations thereof. Examples of suitable unsaturated alkoxysilanes include vinyltrimethoxysilane, allyltrimethoxysilane, allyltriethoxysilane, hexenyltrimethoxysilane, undecylenyltrimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, 3-methacryloyloxypropyltriethoxysilane, 3-acryloyloxypropyltrimethoxysilane, 3-acryloyloxypropyltriethoxysilane, and combinations thereof.

[0093] In some embodiments, the adhesion promoter comprises an epoxy-functional siloxane (such as any of those described above), such as the reaction product of a hydroxy-terminated polyorganosiloxane with an epoxy-functional alkoxysilane, or a physical blend of a hydroxy-terminated polyorganosiloxane with an epoxy-functional alkoxysilane. The adhesion promoter may comprise a combination of an epoxy-functional alkoxysilane and an epoxy-functional siloxane. For example, the adhesion promoter is exemplified by a mixture of 3-glycidoxypropyltrimethoxysilane with the reaction product of a hydroxy-terminated methylvinylsiloxane and 3-glycidoxypropyltrimethoxysilane, or a mixture of 3-glycidoxypropyltrimethoxysilane with a hydroxy-terminated methylvinylsiloxane, or a mixture of 3-glycidoxypropyltrimethoxysilane with a hydroxy-terminated methylvinylsiloxane / dimethylsiloxane copolymer.

[0094] In certain embodiments, the adhesion promoter optionally comprises H2N(CH2)2Si(OCH3)3, H2N(CH2)2Si(OCH2CH3)3, H2N(CH2)3Si(OCH3)3, H2N(CH2)3Si(OCH2CH3)3, CH3NH(CH2)3Si(OCH3)3, CH3NH(CH2)3Si(OCH2CH3)3, CH3NH(CH2)5Si(OCH3)3, CH3NH(CH2)5Si(OCH2CH3)3, H2N(CH2)2NH(C H2)3Si(OCH3)3, H2N(CH2)2NH(CH2)3Si(OCH2CH3)3, CH3NH(CH2)2NH(CH2)3Si(OCH3)3, CH3NH(CH2)2NH(CH2)3Si(OCH2CH3)3, C4H9NH(CH2)2NH(CH2)3Si(OCH3)3, C4H9NH(CH2)2NH(CH2)3Si(OCH2CH3)3, H2N(CH2)2SiCH3(OCH3)2, H2N(CH2)2SiCH3(OCH2CH 3)2, H2N(CH2)3SiCH3(OCH3)2, H2N(CH2)3SiCH3(OCH2CH3)2, CH3NH(CH2)3SiCH3(OCH3)2, CH3NH(CH2)3SiCH3(OCH2CH3)2, CH3 NH(CH2)5SiCH3(OCH3)2, CH3NH(CH2)5SiCH3(OCH2CH3)2, H2N(CH2)2NH(CH2)3SiCH3(OCH3)2, H2N(CH2)2NH(CH2)3SiCH3(OCH2C H3)2, CH3NH(CH2)2NH(CH2)3SiCH3(OCH3)2, CH3NH(CH2)2NH(CH2)3SiCH3(OCH2CH3)2, CH4H9NH(CH2)2NH(CH2)3SiCH3(OCH3)2, CH4H9NH(CH2)2NH(CH2)3SiCH3(OCH2CH3)2, N-(3-(trimethoxysilyl)propyl)ethylenediamine, and the like, as well as combinations thereof. In these or other embodiments, the adhesion promoter comprises a mercapto-functional alkoxysilane, such as 3-mercaptopropyltrimethoxysilane or 3-mercaptopropyltriethoxysilane.

[0095] Additional examples of adhesion promoters include the reaction product of an epoxyalkylalkoxysilane, such as 3-glycidoxypropyltrimethoxysilane, with an amino-substituted alkoxysilane, such as 3-aminopropyltrimethoxysilane, and optionally with an alkylalkoxysilane, such as methyltrimethoxysilane.

[0096] An exemplary adhesion promoter includes a reaction mixture of an amino-containing organoalkoxysilane and an epoxy-containing organoalkoxysilane. Such a reaction mixture is disclosed in Japanese Patent Publication No. 52-8854(B) and Japanese Patent Publication No. 10-195085(A), both of which are incorporated herein by reference.

[0097] The molar ratio of the alkoxysilane having an amino group-containing organic group to the alkoxysilane having an epoxy group-containing organic group is typically within the range of (1:1.5) to (1:5), alternatively within the range of (1:2) to (1:4). This component can be easily synthesized by mixing the alkoxysilane having an amino group-containing organic group and the alkoxysilane having an epoxy group-containing organic group, as mentioned above, and reacting them at room temperature or by heating.

[0098] Specifically, when an alkoxysilane having an amino group-containing organic group is reacted with an alkoxysilane having an epoxy group-containing organic group by the method described in JP-A-10-195085(A), the present invention provides a carbasilatrane derivative that can be obtained by cyclization through an alcohol exchange reaction and is represented by the general formula:

[0099] [ka] In the formula, R 1 is an alkyl group, an alkenyl group, or an alkoxy group, and R 2 are the same or different groups selected from the group consisting of groups represented by the general formula:

[0100] [ka] In the formula, R 4 is an alkylene group or an alkyleneoxyalkylene group, and R 5 is a monovalent hydrocarbon group, and R 6 is an alkyl group and a is 0, 1 or 2; or

[0101] [ka] In the formula, R 7 is an alkylene group, and R 8 is an alkyl group, an alkenyl group, or an acyl group, and R 3 are the same or different hydrogen atoms or alkyl groups. Examples of carbasilatrane derivatives include carbasilatrane derivatives having a silicon-bonded alkoxy group or a silicon-bonded alkenyl group per molecule, as represented by the following structure:

[0102] [ka] In the formula, Rc is a group selected from a methoxy group, an ethoxy group, a vinyl group, an allyl group, and a hexenyl group.

[0103] Furthermore, in the present invention, a silatrane derivative represented by the following structural formula may be used as an adhesion promoter:

[0104] [ka] In the formula, R 1 are the same or different hydrogen atoms or alkyl groups, and R 1 is typically a hydrogen atom or a methyl group. 2are the same or different groups selected from the group consisting of organic groups containing hydrogen atoms, alkyl groups, and alkoxysilyl groups as represented by the general formula: -R 4 -Si(OR 5 ) x R 6 (3-x) In the formula, R 2 At least one of R is an organic group containing an alkoxysilyl group. 2 Examples of the alkyl group include a methyl group. 2 In the organic group containing an alkoxysilyl group, R 4 is a divalent organic group, examples of which include alkylene groups and alkyleneoxyalkylene groups. Typical examples include ethylene groups, propylene groups, butylene groups, methyleneoxypropylene groups, and methyleneoxypentylene groups. Furthermore, R 5 is an alkyl group having 1 to 10 carbon atoms, and is generally a methyl group or an ethyl group. 6 is a substituted or unsubstituted monovalent hydrocarbon group, typically a methyl group. Furthermore, x in the formula is 1, 2, or 3, typically 3.

[0105] R 2 Examples of such organic groups containing an alkoxysilyl group include the following groups: -(CH2)2Si(OCH3)3-(CH2)2Si(OCH3)2CH3 -(CH2)3Si(OC2H5)3-(CH2)3Si(OC2H5)(CH3)2 -CH2O(CH2)3Si(OCH3)3 -CH2O(CH2)3Si(OC2H5)3 -CH2O(CH2)3Si(OCH3)2CH3 -CH2O(CH2)3Si(OC2H5)2CH3 -CH2OCH2Si(OCH3)3-CH2OCH2Si(OCH3)(CH3)2 When used, the adhesion promoter is present in the composition in an amount of from greater than 0 to 3, alternatively from 0.001 to 2.0, weight percent, based on the total weight of the composition.

[0106] The curable silicone composition of the present invention may further contain a filler and / or pigment. If utilized, the filler is different from the thermally conductive filler (C). The filler is not limited and may be, for example, a reinforcing filler, an extending filler, a conductive filler, a flame-retardant filler, an acid-accepting filler, a rheology-modifying filler, a phosphor, a coloring filler, a mineral filler, a glass filler, a carbon filler, or a combination thereof. The selection of filler is typically a function of the cured product to be formed, its composition, and its end-use application.

[0107] The filler may be untreated, pretreated, or added in combination with an optional filler treating agent, as described below, which, if so added, may treat the filler in situ or may treat the filler prior to incorporation into the composition. The filler may be a single filler or a combination of two or more fillers that differ in at least one property, such as filler type, preparation method, treatment or surface chemistry, filler composition, filler shape, filler surface area, average particle size, and / or particle size distribution.

[0108] The shape and size of the filler and / or pigment are also not particularly limited. For example, the filler may be spherical, rectangular, oval, or irregular, and may be in the form of, for example, powder, dust, fibers, flakes, chips, shavings, strands, scrims, wafers, wool, straw, particles, and combinations thereof. The size and shape are typically selected based on the type of filler used, the selection of other ingredients included in the composition, and the end-use application of the cured product formed therefrom.

[0109] Non-limiting examples of fillers that can function as reinforcing fillers include reinforcing silica fillers such as fumed silica, silica aerogel, silica xerogel, and precipitated silica. Fumed silica is known in the art, for example, fumed silica is commercially available fumed silica sold under the name CAB-O-SIL by Cabot Corporation (Massachusetts, USA).

[0110] Non-limiting examples of fillers that may function as extending or reinforcing fillers include quartz and / or crushed quartz, aluminum oxide, magnesium oxide, silica (e.g., fumed silica, ground silica, precipitated silica), hydrated magnesium silicate, magnesium carbonate, dolomite, silicone resin, wollastonite, soapstone, kaolinite, kaolin, mica, muscovite, phlogopite, halloysite (hydrated alumina silicate), aluminum silicate, sodium aluminosilicate, glass (e.g., wind power), Fibers, beads or particles, including recycled glass from turbines or other sources), clay, magnetite, hematite, calcium carbonate, e.g., precipitated calcium carbonate, fumed calcium carbonate, and / or ground calcium carbonate, calcium sulfate, barium sulfate, calcium metasilicate, zinc oxide, talc, diatomaceous earth, iron oxide, clay, mica, chalk, titanium dioxide (titania), zirconia, sand, carbon black, graphite, anthracite, coal, lignite, charcoal, activated carbon, non-functional Silicone resin, alumina, silver, metal powder, magnesium oxide, magnesium hydroxide, magnesium oxysulfate fiber, aluminum trihydrate, aluminum oxide, coated fillers, carbon fiber (including, for example, recycled carbon fiber from the aircraft and / or automotive industries), polyaramid such as chopped KEVLAR™ or TWARON™, nylon fiber, mineral fillers or pigments (e.g., titanium dioxide, non-hydrated, partially hydrated, or hydrated fluorides, chlorides, bromides, iodides, chromates, carbonates, hydroxides, phosphates, hydrogen phosphates, nitrates, oxides, and sulfates of sodium, potassium, magnesium, calcium, and barium; zinc oxide, antimony pentoxide, antimony trioxide, beryllium oxide, chromium oxide, lithopone, boric acid or borates, such as zinc borate, barium metaborate, or aluminum borate, mixed metal oxides, such as vermiculite, bentonite, pumice, perlite, fly ash, clay, and silica gel;Examples of suitable fillers include rice husk ash, ceramics and zeolites, metals such as aluminum flakes or powders, bronze powders, copper, gold, molybdenum, nickel, silver powders or flakes, stainless steel powders, tungsten, barium titanate, silica-carbon black composites, functionalized carbon nanotubes, cement, slate powders, pyrophyllite, sepiolite, zinc stannate, zinc sulfide, and combinations thereof. Alternatively, the extending or reinforcing filler may be selected from the group consisting of calcium carbonate, talc, and combinations thereof.

[0111] As is known in the art, certain fillers can act as pigments. For example, white pigments can include metal oxides such as titanium oxide, aluminum oxide, zinc oxide, zirconium oxide, magnesium oxide, etc.; hollow fillers such as glass balloons and glass beads; and additionally, barium sulfate, zinc sulfate, barium titanate, aluminum nitride, boron nitride, and antimony oxide. Such components can be considered as fillers and / or pigments.

[0112] Extending fillers are known in the art and are commercially available, such as crushed silica sold under the name MIN-U-SIL by US Silica (Berkeley Springs, WV). Suitable precipitated calcium carbonates include Solvay's WINNOFIL™ SPM, and SMI's ULTRA-PFLEX™ and ULTRA-PFLEX™ 100.

[0113] Alternatively or additionally, the filler may comprise a non-reactive silicone resin. For example, the filler may comprise a T resin, a TD resin, a TDM resin, a TDMQ resin, or any other non-reactive silicone resin. Typically, such non-reactive silicone resins contain at least 30 mole percent T siloxy and / or Q siloxy units. As is known in the art, D siloxy units are those that are not part of the R 0 2SiO 2 / 2 and the T siloxy unit is represented by R 0 SiO3 / 2 where R 0 are independently selected substituents.

[0114] Weight average molecular weight M of non-reactive silicone resin w As used herein, M depends at least in part on the molecular weight of the silicone resin and the types of substituents (e.g., hydrocarbyl groups) present in the non-reactive silicone resin. w represents the weight average molecular weight measured using conventional gel permeation chromatography (GPC) with narrow molecular weight distribution polystyrene (PS) standard calibration when the peak representing neopentamer is excluded from the measurement. The PS equivalent weight M of the non-reactive silicone resin w The viscosity of the non-reactive silicone resin may be 12,000 to 30,000 g / mol, typically 17,000 to 22,000 g / mol. The non-reactive silicone resin may be prepared by any suitable method. This type of silicone resin has been prepared by the hydrolysis of the corresponding silane or by the silica hydrosol capping method, which are generally known in the art.

[0115] A phosphor is a type of filler that can convert the wavelength of light emitted from a light source (optical semiconductor device) when the cured product of the composition is used as a wavelength conversion material. There are no specific limitations on the phosphor, and examples of the phosphor include yellow light, red light, green light, and blue light phosphors. These phosphors include oxide phosphors, oxynitride phosphors, nitride phosphors, sulfide phosphors, and oxysulfide phosphors, which are widely used in light emitting diodes (LEDs).

[0116] In certain embodiments, the filler may include an acid acceptor. The acid acceptor may include a metal oxide such as magnesium oxide. Acid acceptors are generally known in the art and are commercially available under trade names including Rhenofit F, Star Mag CX-50, Star Mag CX-150, BLP-3, and MaxOx98LR. Rhenofit F was calcium oxide from Rhein Chemie Corporation (Chardon, Ohio, USA). Star Mag CX-50 was magnesium oxide from Merrand International Corp. (Portsmouth, NH, USA). MagOX 98LR was magnesium oxide from Premier Chemicals LLC (W. Conshohocken, Pa., USA). BLP-3 was calcium carbonate and was from Omya Americas (Cincinnati, Ohio, USA).

[0117] Regardless of the choice of filler, the filler may be added to form the composition untreated, pre-treated, or in combination with an optional filler treating agent, which, when so added, may treat the filler in situ in the composition.

[0118] Filler treating agents may include silanes such as alkoxysilanes, alkoxy-functional oligosiloxanes, cyclic polyorganosiloxanes, hydroxyl-functional oligosiloxanes such as dimethylsiloxane or methylphenylsiloxane, organosilicon compounds, stearic acid, or fatty acids. The filler treating agent may include a single filler treating agent or a combination of two or more filler treating agents selected from similar or different types of molecules.

[0119] The filler treating agent may comprise an alkoxysilane, which may be a monoalkoxysilane, a di-alkoxysilane, a tri-alkoxysilane, or a tetraalkoxysilane. Examples of alkoxysilane filler treating agents include hexyltrimethoxysilane, octyltriethoxysilane, decyltrimethoxysilane, dodecyltrimethoxysilane, tetradecyltrimethoxysilane, phenyltrimethoxysilane, phenylethyltrimethoxysilane, octadecyltrimethoxysilane, octadecyltriethoxysilane, and combinations thereof. In certain embodiments, the alkoxysilane may be used in combination with a silazane, which catalyzes the reaction of the less reactive alkoxysilane with the surface hydroxyl. Such reactions are typically carried out at temperatures above 100°C, under high shear, and with the removal of volatile by-products such as ammonia, methanol, and water.

[0120] Suitable filler treating agents also include alkoxysilyl-functional alkylmethylpolysiloxanes or similar materials in which the hydrolyzable groups can include, for example, silazane, acyloxy, or oximo.

[0121] Alkoxy-functional oligosiloxanes can also be used as filler treating agents. Alkoxy-functional oligosiloxanes and their preparation methods are generally known in the art. Other filler treating agents include mono-end-capped alkoxy-functional polydiorganosiloxanes, i.e., polyorganosiloxanes having an alkoxy functionality at one end.

[0122] Alternatively, filler treating agent can be any of the organosilicon compounds that are typically used to treat silica filler.The example of organosilicon compound includes organochlorosilane such as methyltrichlorosilane, dimethyldichlorosilane and trimethylmonochlorosilane; organosiloxane such as hydroxyl end-blocked dimethylsiloxane oligomer, silicon hydride functional siloxane, hexamethyldisiloxane and tetramethyldivinyldisiloxane; organosilazane such as hexamethyldisilazane and hexamethylcyclotrisilazane; and organoalkoxysilane such as alkylalkoxysilane with methyl, propyl, n-butyl, i-butyl, n-hexyl, n-octyl, i-octyl, n-decyl, dodecyl, tetradecyl, hexadecyl or octadecyl substituent. The organic reactive alkoxysilane may contain amino, methacryloxy, vinyl, glycidoxy, epoxycyclohexyl, isocyanurate, isocyanato, mercapto, sulfide, vinyl-benzyl-amino, benzyl-amino, or phenyl-amino substituents. Alternatively, the filler treating agent may include an organopolysiloxane. The use of such filler treating agents to treat the surface of a filler may utilize multiple hydrogen bonds, either clustered or dispersed, or both, as a method of bonding the organosiloxane to the filler surface. The hydrogen-bondable organosiloxane has, on average, at least one silicon-bonded group capable of hydrogen bonding per molecule. The group may be selected from monovalent organic groups with multiple hydroxyl functionalities or monovalent organic groups with at least one amino functional group. Hydrogen bonding may be the primary form of bonding of the organosiloxane to the filler. The organosiloxane may not be capable of forming covalent bonds with the filler. The hydrogen-bonding capable organosiloxane may be selected from the group consisting of a saccharide-siloxane polymer, an amino-functional organosiloxane, and combinations thereof. Alternatively, the hydrogen-bonding capable polyorganosiloxane may be a saccharide-siloxane polymer.

[0123] Alternatively, filler treating agents may include alkyl thiols such as octadecyl mercaptan, and fatty acids such as oleic acid, stearic acid, titanates, titanate coupling agents, zirconate coupling agents, and combinations thereof. One skilled in the art would be able to optimize the filler treating agent to aid in filler dispersion without undue experimentation.

[0124] If a filler treating agent is used, the relative amounts of filler treating agent and filler are selected based on the particular filler and filler treating agent used and their desired effects or properties.

[0125] In certain embodiments, the composition further comprises an inhibitor, which can be used to modify the reaction rate or cure rate of the composition compared to a composition containing the same starting materials but omitting the inhibitor. Inhibitors include acetylenic alcohols such as methylbutynol, ethynylcyclohexanol, dimethylhexynol, and acetylenic alcohols such as 3,5-dimethyl-1-hexyn-3-ol, 1-butyn-3-ol, 1-propyn-3-ol, 2-methyl-3-butyn-2-ol, 3-methyl-1-butyn-3-ol, 3-methyl-1-pentyn-3-ol, 3-phenyl-1-butyn-3-ol, 4-ethyl-1-octyn-3-ol, and 1-ethynyl-1-cyclohexanol, and combinations thereof; 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane, 1,3,5,7-tetramethyl-1,3,5,7-tetrahexenylcyclotetrasiloxane, and combinations thereof. Siloxanes and cycloalkenylsiloxanes such as methylvinylcyclosiloxanes, exemplified by their combinations; ene-yne ​​compounds, such as 3-methyl-3-penten-1-yne, 3,5-dimethyl-3-hexen-1-yne; triazoles, such as benzotriazole; phosphines; mercaptans; hydrazines; amines, such as tetramethylethylenediamine; dialkyl fumarate, dialkenyl fumarate, dialkoxyalkyl fumarate, maleates, such as diallyl maleate; nitriles; ethers; carbon monoxide; alkenes, such as cyclooctadiene and divinyltetramethyldisiloxane; alcohols, such as benzyl alcohol; and combinations thereof. Alternatively, the inhibitor can be selected from the group consisting of acetylenic alcohols (e.g., 1-ethynyl-1-cyclohexanol) and maleates (e.g., diallyl maleate, bismaleate, or n-propyl maleate), and combinations of two or more thereof.

[0126] Alternatively, the inhibitor may be a silylated acetylenic compound. Without being bound by theory, it is believed that the addition of the silylated acetylenic compound reduces yellowing of the reaction product prepared from the hydrosilylation reaction of the composition when compared to the reaction product from the hydrosilylation of a composition that does not contain the silylated acetylenic compound or a composition that contains an organic acetylenic alcohol inhibitor such as those described above.

[0127] The silylated acetylene compounds are (3-methyl-1-butyn-3-oxy)trimethylsilane, ((1,1-dimethyl-2-propynyl)oxy)trimethylsilane, bis(3-methyl-1-butyn-3-oxy)dimethylsilane, bis(3-methyl-1-butyn-3-oxy)silanemethylvinylsilane, bis((1,1-dimethyl-2-propynyl)oxy)dimethylsilane, methyl(tris(1,1-dimethyl-2-propynyloxy))silane, methyl(tris(3-methyl-1-butyn-3-oxy))silane, (3-methyl-1-butyn-3-oxy)dimethylphenylsilane, (3-methyl-1-butyn-3-oxy)dimethylhexenylsilane, (3-methyl-1-butyn-3-oxy)triethylsilane, bis(3-methyl-1- cyclohexyl-1-ethyn-1-oxy)dimethylhexenylsilane, (cyclohexyl-1-ethyn-1-oxy)dimethylvinylsilane, (cyclohexyl-1-ethyn-1-oxy)diphenylmethylsilane, (cyclohexyl-1-ethyn-1-oxy)trimethylsilane, (cyclohexyl-1-ethyn-1-oxy)trifluoropropylsilane, (3,5-dimethyl-1-hexyn-3-oxy)trimethylsilane, (3-phenyl-1-butyn-3-oxy)diphenylmethylsilane, (3-phenyl-1-butyn-3-oxy)dimethylphenylsilane, (3-phenyl-1-butyn-3-oxy)dimethylvinylsilane, (3-phenyl-1-butyn-3-oxy)dimethylhexenylsilane, (cyclohexyl-1-ethyn-1-oxy)dimethylvinylsilane, (cyclohexyl-1-ethyn-1-oxy)diphenylmethylsilane, (cyclohexyl-1-ethyn-1-oxy)trimethylsilane, and combinations thereof. Alternatively, the inhibitor is exemplified by methyl(tris(1,1-dimethyl-2-propynyloxy))silane, ((1,1-dimethyl-2-propynyl)oxy)trimethylsilane, or a combination thereof. Silylated acetylenic compounds useful as inhibitors may be prepared by methods known in the art, for example, by silylation of the above-mentioned acetylenic alcohols by reaction with chlorosilanes in the presence of an acid acceptor.

[0128] The amount of inhibitor present in the composition will depend on various factors, including the desired pot life of the composition, whether the composition is a one-part or multi-part composition, the particular inhibitor used, and the selection and amounts of components (A)-(G). However, when present, the amount of inhibitor may be from 0% to 1%, alternatively from 0% to 5%, alternatively from 0.001% to 1%, alternatively from 0.01% to 0.5%, or alternatively from 0.0025% to 0.025%, based on the total weight of the composition.

[0129] In some embodiments, the composition further comprises a heat resistance improver other than component (G). The other resistance improver is exemplified by iron oxide (red iron oxide), cerium oxide, cerium dimethylsilanolate, a fatty acid cerium salt, cerium hydroxide, a zirconium compound, copper (Cu) phthalocyanine, or a combination thereof.

[0130] In addition to the above components, optional components can be blended with the thermally conductive silicone composition of the present invention within a range that achieves the objectives of the present invention. Examples of optional components include inorganic fillers (also referred to as "inorganic filler materials"), such as fumed silica, wet silica, ground quartz, titanium oxide, magnesium carbonate, zinc oxide, iron oxide, diatomaceous earth, and carbon black, inorganic fillers obtained by hydrophobizing the surface of such inorganic fillers with organosilicon compounds, organopolysiloxanes that do not contain silicon-bonded hydrogen atoms or silicon-bonded alkenyl groups, heat resistance imparting agents, cold resistance imparting agents, thermally conductive fillers, flame retardants, thixotropy imparting agents, pigments, dyes, etc. Furthermore, if desired, the thermally conductive silicone gel composition of the present invention may contain at least one of known adhesion imparting agents, antistatic agents including cationic surfactants, anionic surfactants, or nonionic surfactants, dielectric fillers, conductive fillers, mold release components, thixotropy imparting agents, antifungal agents, etc. If desired, an organic solvent may be added.

[0131] However, in certain embodiments, the composition is substantially free, alternatively free, of organic solvents. By "substantially free," it is meant, with respect to the composition being substantially free of organic solvents, that the composition comprises less than 10% by weight, alternatively less than 5% by weight, alternatively less than 4% by weight, alternatively less than 3% by weight, alternatively less than 2% by weight, alternatively less than 1% by weight, alternatively 0% by weight, based on the total weight of the composition.

[0132] Examples of organic solvents that are generally not present in the compositions include organic oils such as volatile and / or semi-volatile hydrocarbons, esters, and / or ethers. Common examples of such organic fluids include volatile hydrocarbon oils, e.g., C6-C8 16 Alkanes, C8-C 16 Isoalkanes (e.g., isodecane, isododecane, isohexadecane, etc.), C8 to C 16 Branched esters (e.g., isohexyl neopentanoate, isodecyl neopentanoate, etc.), and the like, as well as derivatives, modifications, and combinations thereof. Additional examples of suitable organic fluids include aromatic hydrocarbons (e.g., benzene, toluene, and xylene), aliphatic hydrocarbons (e.g., heptane, hexane, and octane), alcohols having more than three carbon atoms, aldehydes, ketones (e.g., acetone, methyl ethyl ketone, and methyl isobutyl ketone), amines, esters, ethers, glycols, glycol ethers, alkyl halides, aromatic halides, and combinations thereof. Hydrocarbons include isododecane, isohexadecane, Isopar L (C 11 ~C 13 ), Isopar H(C 11 ~C 12), hydrogenated polydecene. Ethers and esters include isodecyl neopentanoate, neopentyl glycol heptanoate, glycol distearate, dicaprylyl carbonate, diethylhexyl carbonate, propylene glycol n-butyl ether, ethyl-3 ethoxypropionate, propylene glycol methyl ether acetate, tridecyl neopentanoate, propylene glycol methyl ether acetate (PGMEA), propylene glycol methyl ether (PGME), octyldodecyl neopentanoate, diisobutyl adipate, diisopropyl adipate, propylene glycol dicaprylate / dicaprate, octyl ether, octyl palmitate, and combinations thereof.

[0133] The composition can be cured to give a cured product in the form of a silicone gel that has excellent physical properties, including resistance to cracking when exposed to high temperatures for extended periods of time. Because the generation of bubbles and cracks can be suppressed, the silicone gel has excellent bonding properties for electrical or electronic components.

[0134] The composition of the present invention can be prepared by mixing each of the above components. For example, it can be prepared by premixing components (C) and (D), and optionally, component (E), if present, then treating the surface of component (C) with component (D) and, if present, component (E), and then mixing the remaining components and other optional components. Alternatively, the composition can be prepared by mixing components (C) and (D) (and optionally (E)) with component (A), then treating the surface of component (C) with components (C) and (E) (if used), and then mixing the remaining components and other optional components. Similarly, components (B1) and (B2) are typically combined to provide component (B) before combining component (B) with other components. The method for mixing the components can be a conventional, known method and is not particularly limited. However, it is usually preferable to mix the components using a mixing device, as this allows a uniform mixture to be obtained by simple stirring. Such a mixing device is not particularly limited, and examples thereof include a single-screw or twin-screw continuous mixer, a twin roller, a Ross mixer, a Hobart mixer, a dental mixer, a planetary mixer, a kneader mixer, and a Henschel mixer.

[0135] The composition of the present invention can be used as a one-component composition (including a one-liquid type) or, if necessary, as a multi-component composition (multi-liquid type, particularly a two-liquid type) in which multiple separately separated components are mixed at the time of use. In the case of a one-component type, each component of the composition can be placed in a single storage container and used. In the case of a multi-component type, multiple compositions stored separately can be mixed in a predetermined ratio and used. These packages are not particularly limited and can be selected as desired depending on the curing method, application method, and application target described below.

[0136] The compositions of the present invention have excellent fluidity, can be applied precisely, and have excellent gap-filling capabilities. Specifically, the viscosity of the compositions before curing is in the range of 10 to 500 Pa·s at 25°C, more typically in the range of 50 to 400 Pa·s at 25°C.

[0137] The compositions of the present invention cure via a hydrosilylation reaction to form silicone cured products with excellent thermal conductivity and adhesion. The temperature at which the hydrosilylation-curable silicone gel compositions are cured is not particularly limited. Surprisingly, the compositions can be cured at room temperature, which is particularly advantageous for many end uses. If desired, curing can be accelerated using elevated temperatures in the range of 20°C to 150°C, alternatively 20 to 80°C.

[0138] The silicone cured product of the present invention preferably has a hardness that falls within the range of 10 to 70, more preferably 15 to 60, the hardness being measured in accordance with JIS Type A. Furthermore, the silicone cured product has a hardness that remains below 80 (measured in accordance with JIS Type A) even after heating at 200°C for 72 hours.

[0139] The compositions of the present invention can be stably loaded with high amounts of thermally conductive fillers, thereby enabling the compositions and silicone gel cured products to be designed with thermal conductivity of 2.0 W / mK or greater, alternatively 3.0 W / mK or greater, alternatively 3.0 to 7.0 W / mK.

[0140] The composition of the present invention is useful as a heat transfer material that can be interposed at the thermal interface between a heat-generating component and a heat sink or a heat dissipation member such as a circuit board to conduct heat-generating components, and a heat dissipation structure containing the composition can be formed. Here, the type, size, and detailed structure of the heat-generating component are not particularly limited, but the thermally conductive silicone gel composition of the present invention has high thermal conductivity, excellent gap filling ability with components, high adhesion and conformability even to heat-generating components with fine irregularities and narrow gap structures, and the inherent flexibility of a gel. Therefore, the thermally conductive silicone gel composition can be suitably applied to the heat dissipation structures of electric / electronic components or electric / electronic devices, including cell-type secondary batteries.

[0141] Electrical / electronic devices equipped with components made from the thermally conductive silicone composition are not particularly limited. Examples include secondary batteries such as cell-type lithium-ion electrode secondary batteries, cell-stack type fuel cells, electronic circuit boards such as printed circuit boards, IC chips packaged with optical semiconductor elements such as diodes (LEDs), organic electroluminescent elements (OLEDs), laser diodes, and LED arrays, and LSI chips such as CPUs, driver ICs, and memory used in electronic devices such as personal computers, digital video discs, mobile phones, and smartphones. In particular, in high-performance digital switching circuits formed at high integration densities, heat removal (heat dissipation) is an important factor in the performance and reliability of integrated circuits. However, thermally conductive components made from the thermally conductive silicone gel composition of the present invention exhibit excellent heat dissipation and ease of handling even when used in power semiconductor applications such as engine control, powertrain systems, and air conditioning control in air transport. They also exhibit excellent heat resistance and thermal conductivity even when used in harsh environments such as in automotive electronic components such as electronic control units (ECUs). Furthermore, by controlling its rheology, the thermally conductive silicone gel composition of the present invention can be placed on not only horizontal surfaces but also vertical surfaces, and can penetrate into the microstructure of heat-generating components such as electric / electronic components or secondary batteries to provide a gap-free heat dissipation structure. This can improve the heat dissipation properties of electric / electronic devices equipped with heat dissipation structures, alleviating problems such as latent heat and thermal runaway, and the flexible, gel-like cured product can protect the underlying structure of the electric / electronic device, thereby improving reliability and operational stability.

[0142] Examples of materials that make up the above-mentioned electrical / electronic devices include resins, ceramics, glass, and metals such as aluminum. The thermally conductive silicone gel composition of the present invention can be applied to these substrates both as a thermally conductive silicone gel composition (fluid) before curing and as a thermally conductive silicone cured product.

[0143] There are no limitations on the method for forming a heat dissipation structure using the thermally conductive silicone gel composition of the present invention for a heat-generating component, and one example is a method in which the thermally conductive silicone gel composition of the present invention is poured into the heat-dissipating component of an electric / electronic component to sufficiently fill any gaps, and then the composition is left to stand at room temperature or, optionally, heated to harden.

[0144] For applications requiring rapid curing, the heating and curing method is particularly preferred because it allows the entire material to cure relatively quickly. In this case, if the heating temperature is too high, bubbles and cracks are likely to occur in the sealant for the sealed or filled electrical / electronic components. Therefore, heating is preferably carried out at a temperature in the range of 50 to 250°C, and particularly preferably in the range of 70 to 130°C. In the case of thermal curing, the present composition can be formed into a one-component package. In this case, a platinum-containing hydrosilylation reaction catalyst in the form of fine particles dispersed or encapsulated in a thermoplastic resin can be used and is preferred, from the viewpoint of improving the handleability and pot life of the present composition.

[0145] The thermally conductive silicone gel composition of the present invention can be cured at room temperature or by heating at 50°C or lower. In this case, the composition can be packaged in a single pack or multi-pack format. After mixing, the composition is preferably cured at room temperature or by heating at 50°C or lower for one hour to several days.

[0146] The shape, thickness, and arrangement of the thermally conductive silicone gel obtained by the above curing can be designed as desired. After filling the gaps in the electrical / electronic device, the composition may be cured as needed, or may be applied to a film provided with a release layer (separator) or cured thereon, or may be handled alone as a cured product of the thermally conductive silicone gel on the film. Furthermore, in this case, it may be used in the form of a thermally conductive sheet reinforced with a known reinforcing material.

[0147] The thermally conductive silicone gel composition of the present invention has excellent gap-filling properties and forms a gel-like thermally conductive member with excellent flexibility and thermal conductivity.Therefore, it is effective for electrical / electronic components with narrow gaps between electrical elements and packages, between electrical elements and electrical elements, or between electrodes, and for those structures where the silicone gel is difficult to adapt to expansion and contraction.For example, it can be used in semiconductor devices such as secondary batteries, ICs, hybrid ICs, and LSIs, electrical circuits or modules equipped with such semiconductor devices, capacitors, electrical resistors, and other electrical elements, various sensors such as pressure sensors, and igniters and regulators for power equipment such as automobiles, power generation systems, and space transportation systems.

[0148] The following examples are intended to illustrate the present invention and should not be construed as limiting the scope of the invention in any way.

[0149] The specific ingredients utilized in the examples are set forth in Table 1 below.

[0150] The following examples are intended to illustrate the present invention and should not be construed as limiting the scope of the invention in any way.

[0151] The specific ingredients utilized in the examples are set forth in Table 1 below.

[0152] [Table 1]

[0153] Preparation Examples 1 and 2 Base Compositions 1 and 2 were prepared for use in preparing the compositions in later examples. Table 2 below shows the amount of each component present in Base Compositions 1 and 2 produced in Preparative Examples 1 and 2, respectively. The values ​​in Table 2 are in parts by weight, and the total for each of Base Compositions 1 and 2 is 95 parts by weight. Base Compositions 1 and 2 may alternatively be referred to as masterbatches.

[0154] [Table 2]

[0155] General Procedure 1: Preparative Examples 1 and 2 Base Compositions 1 and 2 were prepared according to General Procedure 1. In General Procedure 1, organopolysiloxane (A-1), siloxane macromonomer (D), and alkoxysilane (G) (if used) were placed in a 1 L planetary mixer. Next, filler (C-1) and filler (C-2) were placed in the mixer and mixed at room temperature for 10 minutes. Next, half of the filler (C-4) used was placed in the mixer, followed by an additional 10 minutes of mixing at room temperature. Next, the remaining half of the filler (C-4) used was placed in the mixer, scraped, and mixed for an additional 10 minutes at room temperature.

[0156] Examples 1 to 9 and Comparative Examples 1 to 4 Compositions were prepared in Examples 1-9 and Comparative Examples 1-4. Tables 3 and 4 below show the amounts of each component in Examples 1-9 and Comparative Examples 1-4. Values ​​in Tables 3 and 4 are in parts by weight unless otherwise specified. The SiH / Vi molar ratio reported below for each composition excludes the inhibitor and component (E).

[0157] [Table 3]

[0158] [Table 4]

[0159] Basic Procedure 2: Examples 1 to 9 and Comparative Examples 1 to 4 The compositions of Examples 1 to 9 and Comparative Examples 1 to 4 were prepared according to General Procedure 2. In General Procedure 2, Base Composition 1 or 2 was heated to 160°C under vacuum for 60 minutes, and then cooled to room temperature under vacuum over 30 minutes. Next, the remaining ingredients except for Catalyst (E) were placed in a planetary mixer and mixed at room temperature for 15 minutes. The contents were removed from the mixture, mixed with Catalyst (E), and degassed for 3 minutes. The compositions were then cured to obtain thermally conductive members, and their physical properties were measured as follows.

[0160] hardness The hardness of each thermally conductive member was measured using a JIS Type A hardness tester. Specifically, a mold with plate dimensions of 120 mm x 120 mm x 2 mm was used, with a PTFE sheet between each plate of the mold. Each composition was placed in the mold to form a 2 mm thick sheet and cured in a hot press at 120°C for 60 minutes, after which the JIS Type A hardness was measured using a JIS Type A hardness tester. The hardness was measured by stacking three sheets on top of each other. Additionally, the hardness was measured after aging each thermally conductive member at 200°C for 72 hours.

[0161] Thermal conductivity (hot disk) The thermal conductivity of each thermally conductive member was measured via a hot disk. More specifically, test specimens of the thermally conductive member were prepared in a mold with plate dimensions of 50 mm x 30 mm x 6 mm, with a PTFE sheet between each plate of the mold. Each composition was placed in the mold to form a sheet with a thickness of 6 mm and cured in a hot press at 120°C for 60 minutes. The sheet was removed from the mold and stored at 25°C for 24 hours. The thermal conductivity of two samples was then measured using a Hot Disk TPS 500S manufactured by Hot Disk AB (Gothenburg, Sweden), and averaged and reported below.

[0162] Lap shear strength and cohesive failure rate First, the aluminum die-cast substrate (ADC12) was cleaned with isopropyl alcohol, and then the adhesive strength (MPa) and cohesive failure rate (%) of each thermal conductive member were measured. Each composition was filled into the overlapping area defined by the aluminum die-cast substrate, measuring 10 mm x 24 mm x 1 mm. Each composition was cured in a hot press at 120°C for 60 minutes while placed in the overlapping area defined by the substrate. After curing, excess cured product was removed from around the overlapping area using a cutter, and the properties were measured by a tensile test at a measurement speed of 50 mm / min.

[0163] Tables 5 and 6 below show the physical properties measured for the thermally conductive members formed from the compositions of Examples 1 to 9 and Comparative Examples 1 to 4, respectively.

[0164] [Table 5]

[0165] [Table 6]

Claims

1. A thermally conductive silicone composition comprising: (A) 100 parts by mass of an alkenyl group-containing organopolysiloxane having a viscosity of 10 to 100,000 mPa·s at 25°C; (B) Components (B1) and (B2): (B1) an organosilicon compound of 1 to 100 silicon atoms containing at least one phenylene structure and at least one silicon-bonded hydrogen atom per molecule; and (B2) A mixture of organohydrogenpolysiloxanes containing an average of 2 to 4 silicon-bonded hydrogen atoms per molecule, having a viscosity of 1 to 1,000 mPa·s at 25°C, and not containing a phenylene structure in the molecule, a mixture in which the total amount of silicon-bonded hydrogen atoms in component (B) is 0.5 to 1.1 moles per mole of alkenyl groups contained in component (A), and the molar ratio of silicon-bonded hydrogen atoms in component (B1) to component (B2) is 0.1 to 1.0; (C) 400 to 3,500 parts by mass of a thermally conductive filler; (D) a siloxane macromonomer represented by formula (I) or formula (II): R １ R ２ R ３ Si-[(CH ２ ) ｎ１ (Me ２ SiO) ｍ１ ] ｒ -[O-(Me ２ SiO) ｍ３ ] ｐ -(Me ２ Si) ｏ (CH ２ ) ｎ２ (Me ２ SiO) ｍ２ -CH ２ ) ｎ３ -Si(OR ４ ３ ) ３ (I) where each Me is a methyl group and R １ , R ２ , and R ３ are independently an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 4 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, or —(OSiR ７ R ８ R ９ ) (where R ７ , R ８ , and R ９ are each independently selected from alkyl groups having 1 to 4 carbon atoms; R ４ is an alkyl group having 1 to 4 carbon atoms, n1, n2, m1, m3, and o are integers from 1 to 200, m2, n3, r, and p are integers from 0 to 200, and r and p are not simultaneously 0; (R ５ O) ３ Si-[(CH ２ , ｎ１ (Me ２ SiO) ｍ１ , ｒ -(CH ２ , ｎ４ -[O-(Me ２ SiO)m ３ , ｐ -(Me ２ Si) ｏ -(CH ２ , ｎ２ -Me ２ SiO) ｍ２ -(CH ２ , ｎ３ -Si(OR ６ , ３ (II) In the formula, R ５ and R ６ is an alkyl group having 1 to 4 carbon atoms, n1, m1, m3, o, and n2 are integers from 1 to 200, n3, n4, m2, r, and p are integers from 0 to 200, and r and p are not simultaneously 0; and (E) a catalytic amount of a hydrosilylation reaction catalyst.

2. 2. The thermally conductive silicone composition according to claim 1, further comprising (F) a heat resistance imparting agent.

3. 3. The thermally conductive silicone composition according to claim 1, further comprising (G) an alkoxysilane having an alkyl group with 6 or more carbon atoms.

4. 4. The thermally conductive silicone composition of claim 3, wherein component (G) is a trialkoxysilane having an alkyl group with 6 to 18 carbon atoms.

5. 10. The thermally conductive silicone composition of claim 1, which is substantially free of organic solvents.

6. 2. The thermally conductive silicone composition according to claim 1, which is a room temperature curable thermally conductive silicone composition.

7. 2. The thermally conductive silicone composition according to claim 1, which is a heat-curable thermally conductive silicone composition.

8. A thermally conductive member comprising the thermally conductive silicone composition of claim 1.

9. A thermally conductive member obtained by curing the thermally conductive silicone composition of claim 1.

10. A heat dissipation structure comprising the heat conduction member according to claim 8 or 9.

11. The heat dissipation structure of claim 10, which is an electrical / electronic device.

12. The heat dissipation structure according to claim 10, which is an electric / electronic component or a secondary battery.

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