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

Abstract

The thermally conductive silicone composition comprises (A) 100 parts by mass of an organopolysiloxane containing an alkenyl group; (B) a mixture of components (B1) and (B2), where component (B1) is an organosilicon compound of from 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 organosilicon compound of from 1 to 100 silicon atoms containing on average from 2 to 4 silicon-bonded hydrogen atoms per molecule and having an average of from 1 mPa.s to 1,000 mPa.s at 25 DEG C; the organohydrogenpolysiloxane has a viscosity of 10,000-10,000 mPa * s, but does not contain a phenylene structure in the molecule. The thermally conductive silicone composition further includes (C) 400 to 3500 parts by mass of a thermally conductive filler, and (D) a siloxane macromonomer, and (E) a catalytic amount of a hydrosilylation reaction catalyst. Also provided is a thermally conductive member comprising the thermally conductive silicone composition.

Description

[0001] Cross - reference to related applications

[0002] This application claims the priority and all advantages of U.S. Provisional Application No. 63 / 435,019, filed on December 23, 2022, the content of which is incorporated herein by reference. Technical field

[0003] The present invention relates to a thermally conductive silicone composition having a high thermal conductivity, excellent adhesion even to substrates with poor adhesion (such as aluminum die - casting materials), and soft characteristics after long - term heating. In addition, it can also be applied as a solvent - free thermally conductive silicone composition that can be cured at room temperature. Background art

[0004] In recent years, with the increase in the density and integration of hybrid ICs and printed circuit boards carrying transistors, ICs, memory elements, and other electronic components, as well as the increase in the capacity of secondary batteries (battery types), in order to effectively dissipate the heat generated by electronic and electrical devices such as electronic components and batteries, thermally conductive silicone compositions composed of organopolysiloxanes and thermally conductive fillers such as alumina powder and zinc oxide powder have been widely used. In particular, in order to cope with high heat dissipation, thermally conductive silicone compositions filled with a large amount of thermally conductive fillers have been proposed.

[0005] Conventional thermally conductive silicone compositions treat the surface of thermally conductive fillers with hydrolyzable silanes having long - chain alkyl groups, so that even in the case of high - filled thermally conductive inorganic fillers, flexibility, heat - resistant mechanical properties can be imparted to molded products, and molding performance and processability can be improved by reducing the viscosity increase, thereby enabling high thermal conductivity.

[0006] However, in these thermally conductive silicone compositions, although a certain viscosity reduction and improvement in molding performance can be confirmed, their fluidity is insufficient. Therefore, it is difficult to precisely apply them to highly refined structures of electrical and electronic materials, and when there are gaps between electronic components where heat should be released, sufficient heat dissipation may not be achieved, resulting in latent heat. In addition, when these electronic components require repairability corresponding to positioning, circuit rearrangement, etc., conventional thermally conductive silicone compositions make the thermally conductive cured product easily adhere to the components. Therefore, it is difficult to peel the thermally conductive cured product from the components without residue, which may reduce the yield in the manufacturing process and may hinder the repair or reuse of electronic and electrical devices such as electronic components and batteries. Summary of the invention

[0007] Disclosed is a thermally conductive silicone composition. The thermally conductive silicone composition comprises (A) 100 parts by mass of an alkenyl group-containing organopolysiloxane having a viscosity of 10 mPa·s to 100,000 mPa·s at 25°C. The thermally conductive silicone composition further comprises (B) a mixture of components (B1) and (B2). Component (B1) is an organosilicon compound having 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 and having a viscosity of 1 mPa·s 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 mol to 1.1 mol per 1 mol of alkenyl groups contained 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 further comprises (C) 400 parts by mass to 3,500 parts by mass of a thermally conductive filler; and (D) a siloxane macromonomer represented by the following formula (I) or formula (II):

[0008] 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);

[0009] wherein each Me is a methyl group, R 1 、R 2 and R 3 are independently selected from 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 ), wherein R 7 、R 8 and R 9 are each independently selected from an alkyl group 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;​​

[0010] (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);

[0011] wherein R 5 and R 6 are alkyl groups 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 both 0. Finally, the thermally conductive silicone composition contains (E) a catalytic amount of a hydrosilylation reaction catalyst.

[0012] There is also provided a thermally conductive member containing the thermally conductive silicone composition, and a heat dissipation structure containing the thermally conductive member.

[0013] Problems to be solved

[0014] Conventionally, heat-generating components such as power transistors and thyristors deteriorate in characteristics due to heat generation. Therefore, when installing, a heat sink is provided, and means are taken to dissipate heat and release heat to the metal infrastructure of the device.

[0015] In recent years, there has been an increasing need for reactors in the power control units of hybrid, electric, and fuel cell vehicles to boost the battery voltage and apply it to the motor. In addition, with the miniaturization of the power control unit, as one of the components, the reactor also needs to be miniaturized, and its internal structure has become increasingly miniaturized and complex in recent years.

[0016] In addition, due to the high temperature inside the reactor, a high heat dissipation performance of 0.5 W / mK or more is required. By directly filling the reactor with a heat dissipation material, the heat dissipation area of the entire reactor can be increased.

[0017] Therefore, the potting characteristics and the adhesion to the external housing have become increasingly important. In particular, if the adhesion to the housing is insufficient, peeling occurs during subsequent use, and the heat dissipation performance is significantly reduced. Considering formability and cost, aluminum die casting is mostly used as the material for the external housing. However, aluminum die casting is a substrate or adherend that is difficult to obtain adhesion.

[0018] ​Therefore, it is important to develop products that exhibit high adhesion strength and cohesive failure rate.

[0019] Ways to solve the problems

[0020] Through in-depth research, the present inventors have found that the above problems can be solved by a composition comprising the following:

[0021] (A) 100 parts by mass of an alkenyl group-containing organopolysiloxane having a viscosity of 10 mPa·s to 100,000 mPa·s at 25°C;

[0022] (B) A mixture of components (B1) and (B2):

[0023] (B1) An organosilicon compound having 1 to 100 silicon atoms, the organosilicon compound containing at least one phenylene structure and at least one silicon-bonded hydrogen atom per molecule, and

[0024] (B2) An organohydrogenpolysiloxane containing an average of 2 to 4 silicon-bonded hydrogen atoms per molecule and having a viscosity of 1 mPa·s to 1,000 mPa·s at 25°C but not containing a phenylene structure in the molecule,

[0025] wherein the total amount of silicon-bonded hydrogen atoms in component (B) is 0.5 mol to 1.1 mol per 1 mol 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;

[0026] (C) 400 parts by mass to 3,500 parts by mass of a heat conductive filler;

[0027] (D) A siloxane macromonomer represented by the following formula (I) or formula (II)

[0028] 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)

[0029] where each Me is a methyl group, R 1 、R 2 ​​and R 3 are each independently selected from 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 an alkyl group 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 both 0;

[0030] (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)

[0031] where R 5 and R 6 are alkyl groups 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 both 0; and

[0032] (E) a catalytic amount of a hydrosilylation catalyst

[0033] Advantages of the Invention

[0034] The thermally conductive silicone composition of the present invention has excellent thermal conductivity and adhesion to various substrates, including those known to have poor adhesion, such as die-cast aluminum, including after curing. In addition, the cured thermally conductive silicone composition retains its soft characteristics after long-term exposure to high temperatures. Further, the thermally conductive silicone composition can be formulated as a solvent-free composition and can be cured at room temperature. Detailed Description

[0035] ​The present disclosure provides a thermally conductive silicone composition (the “composition”). The composition and the cured product have excellent physical properties, including thermal conductivity and adhesion to a variety of different substrates, including those known to have poor adhesion properties. Thus, the composition is particularly suitable for use as or as a thermally conductive member and / or heat dissipation structure or as a thermally conductive member and / or heat dissipation structure body. However, the end uses of the composition and the cured product formed therefrom are not limited thereto.

[0036] The composition comprises (A) an alkenyl group-containing organopolysiloxane having a viscosity of 10 mPa·s to 100,000 mPa·s at 25 °C. In some specific examples, component (A) has a viscosity of 10 mPa·s to 10,000 mPa·s, alternatively 10 mPa·s to 9,000 mPa·s, alternatively 10 mPa·s to 8,000 mPa·s, alternatively 10 mPa·s to 7,000 mPa·s, alternatively 10 mPa·s to 6,000 mPa·s, alternatively 10 mPa·s to 5,000 mPa·s, alternatively 10 mPa·s to 4,000 mPa·s, alternatively 10 mPa·s to 3,000 mPa·s, alternatively 10 mPa·s to 2,000 mPa·s, alternatively 10 mPa·s to 1,000 mPa·s at 25 °C. The viscosity can be measured at 25 °C using a Brookfield LV DV-E viscometer with a rotor selected to be suitable for substantially linear polyorganosiloxanes, i.e., viscosities of RV-1 to RV-7.

[0037] As understood by those skilled in the art, organopolysiloxanes contain inorganic silicon-oxygen-silicon groups (i.e., —Si—O—Si—), where organic silicon and / or organic side groups are attached to silicon atoms in M, D, T, and / or Q siloxane units. Organopolysiloxanes are typically characterized by the number, type, and / or ratio of [M], [D], [T], and / or [Q] units / siloxane groups, which each represent the structural units of the respective functional groups present in the organopolysiloxane resin. Specifically, [M] represents the monofunctional unit of the general formula R″3SiO 1 / 2 ; [D] represents the difunctional unit of the general formula R″2SiO 2 / 2 ; [T] represents the trifunctional unit of the general formula R″SiO 3 / 2 ; and [Q] represents the tetrafunctional unit of the general formula SiO 4 / 2 as shown in the following general structural moieties:

[0038]

[0039] In these general structural moieties, each R″ is independently a monovalent or polyvalent substituent. As understood in the art, there is no particular limitation on the specific substituents applicable to each R″ (e.g., it can be monoatomic or polyatomic, organic or inorganic, linear or branched, substituted or unsubstituted, aromatic, aliphatic, saturated or unsaturated, etc., as well as various combinations thereof).

[0040] Those skilled in the art understand how the [M], [D], [T], and [Q] units and their relative proportions (i.e., mole fractions) affect and control the structure of the siloxane, and depending on the selection of the [M], [D], [T], and / or [Q] units therein, the polysiloxane can generally be monomeric, polymeric, oligomeric, linear, branched, cyclic, and / or resinous. For example, [T] units and / or [Q] units are present in organopolysiloxane resins, while linear organopolysiloxanes generally do not contain such [T] units and / or [Q] units.

[0041] In a specific embodiment, component (A) does not contain Q units. In these or other embodiments, component (A) does not contain both T and Q units. Specifically, component (A) is generally linear. The alkenyl groups are silicon-bonded and can be present at terminal positions (i.e., in one or more M units), and / or at side-chain positions (i.e., in one or more D units).

[0042] For example, component (A) can have the following average formula: R a' SiO (4-a') / 2 , where each R is independently selected from substituted or unsubstituted hydrocarbon groups, provided that at least two of the Rs are independently alkenyl groups, and where the subscript a′ is selected such that 1.9 ≤ a′ ≤ 2.2.

[0043] Typically, the hydrocarbyl groups suitable for R can independently be straight-chain, branched-chain, cyclic, or a combination thereof. Cyclic hydrocarbyl groups include aryl groups and saturated or non-conjugated cyclic groups. The cyclic hydrocarbyl groups can independently be monocyclic or polycyclic. The straight-chain and branched-chain hydrocarbyl groups can independently be saturated or unsaturated. An example of a combination of linear and cyclic hydrocarbyl groups is an aralkyl group. General examples of hydrocarbyl groups include alkyl groups, aryl groups, alkenyl groups, halo-carbon groups, etc., as well as their derivatives, modifications, and combinations. 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 halo-hydrocarbon groups (i.e., hydrocarbyl groups) include haloalkyl groups, aryl groups, and combinations thereof. Examples of haloalkyl groups include alkyl groups in which one or more of the above hydrogen atoms are replaced by a halogen atom such as F or Cl. Specific examples of haloalkyl 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, as well as their derivatives. Examples of haloaryl groups include aryl groups in which one or more of the above hydrogen atoms are replaced by a halogen atom such as F or Cl. Specific examples of haloaryl groups include chlorobenzyl and fluorobenzyl groups.

[0044] In a specific embodiment, each R is independently selected from alkyl groups having from 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 atom, and ethylenically unsaturated (i.e., alkenyl and / or alkynyl groups) groups having from 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.

[0045] "Alkenyl" means an acyclic, branched or unbranched monovalent hydrocarbon group having one or more carbon-carbon double bonds. Specific examples thereof include vinyl groups, allyl groups, hexenyl groups and octenyl groups. Various examples of ethylenically unsaturated groups include CH2=CH—, CH2=CHCH2—, CH2=CH(CH2)4—, CH2=CH(CH2)6—, CH2=C(CH3)CH2—, H2C=C(CH3)—, H2C=C(CH3)—, H2C=C(CH3)CH2—, H2C=CHCH2CH2—, H2C=CHCH2CH2CH2—. Generally, when R is an ethylenically unsaturated group, the ethylenic unsaturation is at the end of R. As understood in the art, ethylenic unsaturation may be referred to as aliphatic unsaturation.

[0046] When (A) the organopolysiloxane is substantially linear, alternatively linear, at least two aliphatic unsaturated groups may be bonded to silicon atoms in side chain positions, terminal positions or both side chain positions and terminal positions.

[0047] When (A) the organopolysiloxane is a substantially linear polyorganosiloxane, examples of (B) the organopolysiloxane can include: dimethylpolysiloxane capped at both molecular ends with dimethylethenylsilyloxy groups; methylphenylpolysiloxane capped at both molecular ends with dimethylethenylsilyloxy groups; a copolymer of methylphenylsiloxane and dimethylsiloxane capped at both molecular ends with dimethylethenylsilyloxy groups; a copolymer of methylvinylsiloxane and methylphenylsiloxane capped at both molecular ends with dimethylethenylsilyloxy groups; a copolymer of methylvinylsiloxane and diphenylsiloxane capped at both molecular ends with dimethylethenylsilyloxy groups; a copolymer of methylvinylsiloxane, methylphenylsiloxane and dimethylsiloxane capped at both molecular ends with dimethylethenylsilyloxy groups; a copolymer of methylvinylsiloxane and methylphenylsiloxane capped at both molecular ends with trimethylsilyloxy groups; a copolymer of methylvinylsiloxane and diphenylsiloxane capped at both molecular ends with trimethylsilyloxy groups; and a copolymer of methylvinylsiloxane, methylphenylsiloxane and dimethylsiloxane capped at both molecular ends with trimethylsilyloxy groups.

[0048] In a specific embodiment, component (A) is selected from the group consisting of:

[0049] i) Dimethylethenylsilyloxy-capped polydimethylsiloxane,

[0050] ii) Dimethylethenylsilyloxy-capped poly(dimethylsiloxane / methylvinylsiloxane),

[0051] iii) Dimethylethenylsilyloxy-capped polymethylvinylsiloxane,

[0052] iv) Trimethylsilyloxy-capped poly(dimethylsiloxane / methylvinylsiloxane),

[0053] v) Trimethylsilyloxy-capped polymethylvinylsiloxane,

[0054] vi) Dimethylethenylsilyloxy-capped poly(dimethylsiloxane / methylvinylsiloxane),

[0055] vii) Dimethylethenylsilyloxy-capped poly(dimethylsiloxane / methylphenylsiloxane),

[0056] viii) Dimethylethenylsilyloxy-capped poly(dimethylsiloxane / diphenylsiloxane),

[0057] ix) Phenyl, methyl, vinyl-silyloxy-capped polydimethylsiloxane,

[0058] x) Polydimethylsiloxane endblocked with dimethylhexenylsilyloxy,

[0059] xi) Poly(dimethylsiloxane / methylhexenylsiloxane) endblocked with dimethylhexenylsilyloxy,

[0060] xii) Polymethylhexenylsiloxane endblocked with dimethylhexenylsilyloxy,

[0061] xiii) Poly(dimethylsiloxane / methylhexenylsiloxane) endblocked with trimethylsilyloxy,

[0062] xiv) Polymethylhexenylsiloxane endblocked with trimethylsilyloxy,

[0063] xv) Poly(dimethylsiloxane / methylhexenylsiloxane) endblocked with dimethylhexenylsilyloxy,

[0064] xvi) Poly(dimethylsiloxane / methylhexenylsiloxane) endblocked with dimethylethenylsilyloxy, and

[0065] xvii) Combinations thereof.

[0066] Component (A) may contain one or more types of alkenyl group-containing organopolysiloxanes. The molecular structure of the alkenyl group-containing organopolysiloxane of component (A) is not particularly limited, and examples may include linear, branched, cyclic, and three-dimensional network structures, and combinations thereof. Component (A) may 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.

[0067] The composition contains component (A) in an amount of 100 parts by weight.

[0068] The composition further contains a mixture of components (B) (B1) and (B2). Generally, 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) may be formed in situ by mixing components (B1) and (B2) in the presence of one or more other components of the composition.

[0069] Component (B1) is a silicone compound having 1 to 100 silicon atoms, alternatively 2 to 30 silicon atoms, 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) effectively imparts adhesiveness to the composition. In this sense, component (B1) can be referred to as a tackifier.

[0070] Examples of component (B1) include silicone compounds having 1 to 100 silicon atoms, alternatively 2 to 30 silicon atoms, alternatively 2 to 20 silicon atoms, and alternatively 4 to 10 silicon atoms. The silicone compound of component (B1) can be a linear or cyclic silicone oligomer or silane having at least one, usually 1 to 20, alternatively 2 to 10 SiH groups (i.e., silicon-bonded hydrogen atoms) per molecule, having at least one, usually 1 to 4 phenylene structures, and can also contain one or more functional groups including epoxy groups (such as glycidoxy), alkoxysilyl groups (such as trimethoxysilyl, triethoxysilyl, and methyldimethoxysilyl), esters, acrylic acid, methacrylic acid, carboxylic anhydrides, isocyanates, amino, or amide groups.

[0071] In a specific embodiment, component (B1) has the following structure:

[0072]

[0073] where each subscript n is independently an integer from 1 to 3, and each D 1 is independently selected from divalent hydrocarbon groups and covalent bonds. When D 1 is a covalent bond, only oxygen atoms exist between the phenylene moiety and the cyclic siloxane moiety. In certain embodiments, each D 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.

[0074] Examples of silicone compounds suitable for component (B1) are illustrated as follows:

[0075]

[0076]

[0077] wherein n is independently an integer from 1 to 4. In the above structure, any O(CH2)3 moiety bridging each phenylene moiety and each cyclic siloxane moiety can be replaced by, for example, O, OCH2, O(CH2)2, etc.

[0078] Additional examples of component (B1) are as follows:

[0079]

[0080] wherein X is:

[0081]

[0082] In the above examples, Y is any one of the following groups:

[0083]

[0084] wherein n is an integer from 1 to 4; and

[0085]

[0086] wherein R' is a group selected from:

[0087] -O-CH2CH2CH2-, -CH2CH2CH2-,

[0088] —OCH , CH , CH2O-,

[0089] and

[0090] wherein R w and R x are each independently a substituted or unsubstituted monovalent hydrocarbon group, wherein q is an integer from 1 to 50, alternatively 1 to 20, wherein h is an integer from 0 to 100, alternatively 1 to 50, wherein R" is a group selected from:

[0091]

[0092] and

[0093] wherein R w and R x are as defined above, and y is an integer from 0 to 100, wherein Y' is any one of the groups:

[0094]

[0095] wherein n is an integer from 1 to 4, and

[0096] wherein R w 、R x 、q and h are as defined above, and z is an integer from 1 to 10.

[0097] Suitable optionally substituted monovalent hydrocarbon groups represented by R w and R x include those groups described above for R. The hydrocarbon groups described for R can be substituted by alkoxy groups, acrylic acid, methacrylic acid, acryloyl, methacryloyl, amino or alkylamino groups in R w and / or R x .

[0098] Additional examples of component (B1) include the silicone compounds exemplified above, which have alkoxysilyl groups (such as trimethoxysilyl, triethoxysilyl or methyldimethoxysilyl), acrylic acid, methacrylic acid, esters, carboxylic anhydrides, isocyanates, amino or amide groups further introduced therein.

[0099] The content of silicon-bonded hydrogen atoms (SiH content) in the silicone compounds of component (B1) is generally 0.001 mol / g to 0.01 mol / g, more preferably 0.002 mol / g to 0.01 mol / g.

[0100] The silicone compounds of component (B1) generally do not contain any alkenyl groups. When an alkenyl-containing silicone compound is used as component (B1), its amount should be such that the molar ratio of the total SiH groups in the composition to the total silicon-bonded alkenyl groups in the composition is 1.0 to 5.0, alternatively 1.2 to 4.0, and alternatively 1.5 to 3.0.

[0101] Component (B2) is an organohydrogenpolysiloxane containing on average 2 to 4 silicon-bonded hydrogen atoms per molecule and having a viscosity of 1 mPa·s to 1,000 mPa·s at 25°C. Different from component (B1), component (B2) does not have a phenylene structure in the molecule. Component (B2) is used as a crosslinking agent or chain extender for component (A) because the SiH groups in its molecule undergo hydrosilylation or addition reaction with the silicon-bonded alkenyl groups in component (A). The organohydrogenpolysiloxane as component (B2) is generally linear.

[0102] In some embodiments, component (B2) contains silicon-bonded hydrogen atoms only at the molecular ends. In other words, in such embodiments, component (B2) does not contain silicon-bonded hydrogen atoms at the side-chain positions, i.e., the hydrogen atoms bonded to the silicon atoms in the D siloxane units. In other embodiments, component (B2) contains silicon-bonded hydrogen atoms only at the side-chain positions, i.e., the hydrogen atoms bonded to the silicon atoms in the D siloxane units. In other words, in such embodiments, component (B2) does not contain silicon-bonded hydrogen atoms at the terminal positions, i.e., the hydrogen atoms bonded to the silicon atoms in the M siloxane units. In still other embodiments, component (B2) contains silicon-bonded hydrogen atoms at both the side-chain positions and the terminal positions.

[0103] In a specific embodiment, component (B2) has an average unit formula: (HR 10 2SiO 1 / 2 )(R 10 2SiO 2 / 2 ) n '(HR 10 2SiO 1 / 2 ), where each R 10 is an independently selected hydrocarbon group, alternatively an independently selected alkyl group, and the subscript n' is selected to give component (B2) a viscosity at 25 °C of from 1 mPa·s to 1,000 mPa·s, alternatively from 10 mPa·s to 500 mPa·s. In other embodiments, the linear organohydrogenpolysiloxane has an average unit formula: (R 10 3SiO 1 / 2 )(R 10 2SiO 2 / 2 ) x '(HR 10 SiO 2 / 2 )y'(R 10 3SiO 1 / 2 ), where each R 10 is an independently selected hydrocarbon group, alternatively an independently selected alkyl group, and the subscript y' is from 2 to 4, and the subscript x' is selected to give component (B) a viscosity at 25 °C of from 1 mPa·s to 1,000 mPa·s, alternatively from 10 mPa·s to 500 mPa·s

[0104] In another specific embodiment, component (B2) has an average formula:

[0105] H(CH3)2SiO[(CH3)2SiO 2 / 2 n'Si(CH3)2H

[0106] where n' is defined as above. In different specific embodiments, component (B2) has an average formula:

[0107] (CH3)3SiO[(CH3)2SiO 2 / 2 x'(H(CH3)SiO 2 / 2 )y'OSi(CH3)3

[0108] wherein x' and y' are defined as above. Component (B2) may comprise a combination of two or more different organohydrogenpolysiloxanes that differ in at least one property such as structure, molecular weight, degree of polymerization, viscosity, etc.

[0109] The total amount of silicon-bonded hydrogen atoms in component (B) (including those attributable to both component (B1) and component (B2)) is 0.5 mol to 1.1 mol, alternatively 0.6 mol to 1.1 mol, alternatively 0.7 mol to 1.1 mol per 1 mol of alkenyl groups contained in component (A). In addition, 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, alternatively 0.15 to 0.60. When the reaction ratio of component (B) or the molar ratio of SiH in (B1) to SiH in (B2) is outside the said range, the soft characteristics of the composition after heating may be impaired or insufficient.

[0110] The composition further comprises (C) 400 parts by mass to 3,500 parts by mass of a heat-conductive filler.

[0111] The heat-conductive filler (C) is used to impart thermal conductivity to the composition and to the heat-conductive member obtained by curing the composition. This component (C) is generally at least one or more types of powders and / or fibers 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 them, the most typical are metal powders, metal oxide powders, metal nitride powders, or carbon powders.

[0112] All or part of the heat-conductive filler (C) is optionally but usually surface-treated with an alkoxysilane of the following component (G). In addition, those powders and / or fibers that have been 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) include, in addition to component (G), surfactants, other silane coupling agents, aluminum-based coupling agents, silicone-based surface treatment agents, etc.

[0113] 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 composed of two or more types of 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 aluminum oxide, 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, fullerene, carbon nanotube, graphene, activated carbon, and monolithic 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 ferrites, Mn-Mg-Zn ferrites, Mg-Cu-Zn ferrites, Ni-Zn ferrites, Ni-Cu-Zn ferrites, and Cu-Zn ferrites.

[0114] [In a specific embodiment, component (C) comprises silver powder, aluminum powder, aluminum oxide powder, zinc oxide powder, aluminum nitride powder, or graphite. In cases where electrical insulation is required, metal oxide-based powders or metal nitride-based powders are preferably used; aluminum oxide powder, zinc oxide powder, or aluminum nitride powder is particularly preferred.

[0115] The shape of component (C) is not particularly limited, and examples thereof include spherical, needle-like, disk-like, rod-like, irregular shapes, but usually spherical or irregular shapes. The average particle size of component (C) is not particularly limited, but is usually in the range of 0.01 μm to 100 μm, and alternatively in the range of 0.01 μm to 50 μm.

[0116] In a specific embodiment, component (C) comprises (C1) a layered boron nitride powder having an average particle size of 0.1 μm to 30 μm, (C2) a particulate boron nitride powder having an average particle size of 0.1 μm to 50 μm, (C3) a spherical and / or crushed alumina powder having an average particle size of 0.01 μm to 50 μm, or (C4) spherical and / or pulverized graphite having an average particle size of 0.01 μm to 50 μm; or a mixture of two or more types thereof. Most typically, it is a mixture of two or more types of spherical and pulverized alumina powders having an average particle size of 0.01 μm to 50 μm. Combining alumina powders with larger particle sizes and alumina powders with smaller particle sizes in a ratio according to the closest packing theory distribution curve can particularly improve the filling efficiency, reduce the viscosity, and increase the thermal conductivity.

[0117] The content of component (C) in the composition ranges from 400 parts by mass to 3,500 parts by mass, alternatively 400 parts by mass 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 obtained composition tends to be insufficient, and if the content of component (C) exceeds the upper limit of the aforementioned range, the viscosity of the obtained composition significantly increases even when component (G) is blended or used for surface treatment of component (C), and thus, the processability, gap filling ability, etc. tend to deteriorate.

[0118] In addition, the composition contains (D) a siloxane macromonomer represented by the following formula (I) and / or formula (II).

[0119] The formula (I) is as follows:

[0120] 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)

[0121] where each Me is a methyl group, and R 1 、R 2 and R 3 are independently selected from 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 )), wherein 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.

[0122] Component (D) has the following formula (II):

[0123] (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)

[0124] wherein R 5 and R 6 are alkyl groups 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.

[0125] In certain embodiments, component (D) can be considered a surface treating agent. For example, without wishing to be bound by theory, it is believed that the compound of formula (I) can readily bind to the surface of a filler such as component (C) by chemical and / or physical bonds and impart better affinity to the filler through the organopolysiloxane, thereby enabling the composition to flow and have good processability even when a large amount of filler is loaded.

[0126] Specific examples of the compound represented by formula (I) include, but are not limited to:

[0127] ·ViMe2SiO(Me2SiO) 27 SiMe2-(CH2)2-(Me2SiO)2-(CH2)2—Si(OMe)3,

[0128] ·ViMe2SiO(Me2SiO) 58 ​SiMe2-(CH2)2-(Me2SiO)2—(CH2)2—Si(OMe)3,

[0129] ·ViMe2SiO(Me2SiO) 125 SiMe2-(CH2)2-(Me2SiO)2—(CH2)2—Si(OMe)3,

[0130] ·(OSiMe3)2SiMe-(CH2)2-Me2SiO(Me2SiO) 58 SiMe2-(CH2)2-(Me2SiO)2-

[0131] (CH2)2-Si(OMe)3,

[0132] ·C8H 17 -(Me2SiO) 25 SiMe2-(CH2)6—Si(OMe)3,

[0133] ·C8H 17 -(Me2SiO) 45 SiMe2-(CH2)6—Si(OMe)3,

[0134] ·(C8H 17 -(Me2SiO) 65 SiMe2-(CH2)6—Si(OMe)3) and

[0135] ·(C8H 17 -(Me2SiO) 115 SiMe2-(CH2)6—Si(OMe)3).

[0136] Specific examples of the compounds represented by formula (II) include, but are not limited to:

[0137] ·(OMe)3Si—(CH2)2-(Me2SiO)2—(CH2)2-Me2SiO(Me2SiO) 27 SiMe2-

[0138] (CH2)2-(Me2SiO)2—(CH2)2—Si(OMe)3,

[0139] ·(OMe)3Si—(CH2)2-(Me2SiO)2—(CH2)2-Me2SiO(Me2SiO) 58 SiMe2-

[0140] (CH2)2-(Me2SiO)2—(CH2)2—Si(OMe)3,

[0141] ·(OMe)3Si—(CH2)2-(Me2SiO)2—(CH2)2-Me2SiO(Me2SiO) 125 SiMe2-

[0142] (CH2)2-(Me2SiO)2—(CH2)2—Si(OMe)3,

[0143] (OMe)3Si—(CH2)6-(Me2SiO) 25 SiMe2-(CH2)6—Si(OMe)3,

[0144] (OMe)3Si—(CH2)6-(Me2SiO) 45 SiMe2-(CH2)6—Si(OMe)3,

[0145] (OMe)3Si—(CH2)6-(Me2SiO) 65 SiMe2-(CH2)6—Si(OMe)3 and

[0146] (OMe)3Si—(CH2)6-(Me2SiO) 115 SiMe2-(CH2)6—Si(OMe)3.

[0147] In certain embodiments, component (D) comprises a compound of formula (I), alternatively consisting of a compound of formula (I), excluding those of formula (II). In other embodiments, component (D) comprises a compound of formula (II), alternatively consisting of a compound of formula (II), excluding those of formula (I). In other embodiments, component (D) comprises a blend of compounds of formula (I) and formula (II). In such embodiments, that is, in the case of utilizing a blend, the molar ratio of the compound of formula (I) to the compound of formula (II) ((I) / (II)) is 2 to 15, and alternatively 6 to 12. In addition, component (D) may comprise a combination of two or more different compounds that do not belong to formula (I), do not belong to formula (II), or do not belong to both.

[0148] Although the composition includes a large amount of thermally conductive filler (C), component (D) still provides the desired processability of the composition. Since the compounds of formula (I) and (II) have terminal alkoxy groups, component (D) can react with the hydroxyl groups on the surface of the filler (thermal conductive filler (C)). Based on the total weight of the composition, the amount of component (D) in the composition is 0.01 wt % to 20 wt %, alternatively 0.1 wt % to 10 wt %. In a specific embodiment, based on 100 parts by weight of component (A), the amount of component (D) in the composition is 0.005 parts by weight to 10 parts by weight.

[0149] The composition further comprises (E) a catalytic amount of a hydrosilylation catalyst. Those skilled in the art can readily determine the catalytic amount 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 can be any known hydrosilylation catalyst for catalyzing hydrosilylation reactions. Combinations of different hydrosilylation catalysts can be used as component (E).

[0150] The hydrosilylation catalyst can be located within the solid support or on the solid support. Examples of supports include activated carbon, silica, silica-alumina, alumina, zeolites, and other inorganic powders / granules (e.g., sodium sulfate), etc. The (E) hydrosilylation catalyst can also be provided in a medium, such as a solvent that dissolves the (E) hydrosilylation catalyst, or alternatively a medium that only carries but does not dissolve the (E) hydrosilylation catalyst. Such media are known in the art.

[0151] In a specific embodiment, the (E) hydrosilylation catalyst comprises platinum. In these embodiments, the (E) hydrosilylation catalyst is exemplified by, for example, platinum black, compounds such as chloroplatinic acid, chloroplatinic acid hexahydrate, the reaction product of chloroplatinic acid and a monohydric alcohol, bis(ethyl acetoacetato)platinum, bis(acetylacetonato)platinum, platinum chloride, and complexes of such compounds with olefins or organopolysiloxanes, and platinum compounds microencapsulated in a matrix or core-shell type compound. Microencapsulated hydrosilylation catalysts and methods for their preparation are also known in the art, as illustrated in U.S. Patents 4,766,176 and 5,017,654, which are incorporated herein by reference in their entireties.

[0152] The complex of platinum and an organopolysiloxane suitable for use as a hydrosilylation catalyst (E) contains 1,3-divinyl-1,1,3,3-tetramethyldisiloxane; 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane; alkenylsiloxanes obtained by substituting a part of the methyl groups of these alkenylsiloxanes with ethyl groups, phenyl groups, etc.; and alkenylsiloxanes obtained by substituting a part of the vinyl groups of these alkenylsiloxanes with allyl groups, hexenyl groups, etc. In particular, since the platinum-alkenylsiloxane complex has good stability, 1,3-divinyl-1,1,3,3-tetramethyldisiloxane is usually used and is usually added in the form of a complexed alkenylsiloxane solution. These complexes can be microencapsulated in a resin matrix. Alternatively, the hydrosilylation catalyst (E) can contain a complex of 1,3-divinyl-1,1,3,3-tetramethyldisiloxane and platinum. The hydrosilylation catalyst (E) can be prepared by a method including reacting chloroplatinic acid with an aliphatic unsaturated organosilicon compound such as divinyltetramethyldisiloxane or an olefin-platinum-silyl complex.

[0153] The hydrosilylation catalyst (E) can also or alternatively be a photoactivatable hydrosilylation catalyst, which can initiate curing via irradiation and / or heating. The photoactivatable hydrosilylation catalyst can be any hydrosilylation catalyst that can catalyze the hydrosilylation reaction especially when exposed to radiation with a wavelength of 150 nanometers to 800 nanometers (nm).

[0154] Specific examples of the photoactivatable hydrosilylation catalyst applicable to the hydrosilylation catalyst (E) include, but are not limited to, β-diketonato platinum(II) complexes such as bis(2,4-pentanedionato)platinum(II), bis(2,4-hexanedionato)platinum(II), bis(2,4-heptanedionato)platinum(II), bis(1-phenyl-1,3-butanedionato)platinum(II), bis(1,3-diphenyl-1,3-propanedionato)platinum(II), bis(1,1,1,5,5,5-hexafluoro-2,4-pentanedionato)platinum(II); (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-C6H4NNNOC6H 11 4, Pt[p-H3COC6H4NNNOC6H 11 4, Pt[p-CH3(CH2)x-C6H4NNNOCH3]4, 1,5-cyclooctadiene.Pt[p-CN-C6H4NNNOC6H 112, 1,5 - cyclooctadiene, Pt[p-CH3O-C6H4NNNOCH3]2, [(C6H5)3P]3Rh[p-CN-C6H4NNNOC6H 11 and Pd[p-CH3(CH2)x—C6H4NNNOCH3]2, where x is 1, 3, 5, 11 or 17; (η-diene)(σ-aryl)platinum complexes such as (η 4 -1,5-cyclooctadienyl)diphenylplatinum, (η 4 -1,3,5,7-cyclooctatetraenyl)diphenylplatinum, (η 4 -2,5-norbornenyl)diphenylplatinum, (η 4 -1,5-cyclooctadienyl)bis-(4-dimethylaminophenyl)platinum, (η 4 -1,5-cyclooctadienyl)bis-(4-acetylphenyl)platinum and (η 4 -1,5-cyclooctadienyl)bis-(4-trifluoromethylphenyl)platinum. Generally, the photoactivatable hydrosilylation catalyst is a Pt(II) β-diketone complex, and more generally, the catalyst is platinum(II) bis(2,4-pentanedionate).

[0155] The hydrosilylation catalyst (E) is present in the composition in a catalytic amount (i.e., an amount or quantity sufficient to promote its curing under the desired conditions). The hydrosilylation catalyst can be a single hydrosilylation catalyst or a mixture comprising two or more different hydrosilylation catalysts.

[0156] The catalytic amount of the hydrosilylation catalyst (E) can be an amount in the range of 0.01 ppm to 500 ppm, 0.01 ppm to 100 ppm or 0.01 ppm to 50 ppm by mass of metal atoms relative to the entire composition.

[0157] In certain embodiments, the composition further comprises (F) a heat resistance imparting agent to enhance the heat resistance of the thermally conductive silicone composition and its cured product. Component (F) is not particularly limited, provided that component (F) is selected to impart heat resistance to the composition and its cured product. Examples thereof 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 silanol; cerium fatty acid salts; reaction products of organopolysiloxane and cerium carboxylate. Phthalocyanine compounds generally use additives such as those disclosed in JP2014-503680A, which are incorporated herein by reference, for example, additives selected from the group consisting of metal-free phthalocyanine compounds and metal-containing phthalocyanine compounds. Among the metal-containing phthalocyanine compounds, copper phthalocyanine compounds are the most typical. A specific and non-limiting heat resistance imparting agent is 29H,31H-phthalocyanato(2-)-N29,N30,N31,N32copper. Such phthalocyanine compounds are commercially available, for example, STAN-TONE TM 40SP03.

[0158] Blends of different heat resistance imparting agents can be used together as component (F). The amount of component (F) can range from 0.01% to 5.0% by mass of the total composition. It can range from 0.05% to 0.2% and from 0.07% to 0.1% by mass.

[0159] In certain embodiments, the composition further comprises (G) an alkoxysilane. The alkoxysilane contains 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 a hexyl group, an octyl group, a dodecyl group, a tetradecyl group, a hexadecyl group, and an octadecyl group, and an aralkyl group such as a benzyl group and a phenethyl group. In other words, the aralkyl group is considered an alkyl group for the purpose of component (G). An alkyl group having 6 to 20 carbon atoms is particularly preferred. When the alkyl group of the alkoxysilane has less than 6 carbon atoms, the effect of reducing the viscosity of the composition is insufficient, so the viscosity of the composition may increase, and the required fluidity and gap filling ability may not be achieved. In addition, when using an alkoxysilane having an alkyl group with 20 or more carbon atoms, in addition to poor industrial feasibility, the compatibility may deteriorate depending on the type of component (A).

[0160] In certain embodiments, component (G) is represented by the following structural formula: Y n Si(OR) 4-n, where 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 the OR group include a methoxy group, an ethoxy group, a propoxy group, and a butoxy group.

[0161] Specific examples of suitable alkoxysilanes 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 Si(OC2H5)3, etc.

[0162] The usage 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 foregoing range, the effect of reducing the viscosity of the composition may be insufficient. If the usage amount of component (G) exceeds the upper limit of the foregoing range, the effect of reducing the viscosity may saturate, and the alkoxysilane may be further separated, resulting in a decrease in the storage stability of the composition. If component (G) is used, it may comprise a combination of two or more different organopolysiloxane resins that are different in at least one property such as structure, molecular weight, monovalent groups bonded to silicon atoms, etc.

[0163] In various embodiments, component (G) is blended in a form such that component (C) is surface-treated with component (G). From the viewpoint of improving the fluidity and gap-filling ability of the composition, it is desirable that at least a part of component (C) is surface-treated with component (G). When component (G) is used as a surface treatment agent, its amount is usually 0.15% to 1.2% by mass, alternatively 0.2% to 1.0% by mass, relative to component (C).

[0164] The surface treatment method using component (G) is not particularly limited, but a direct treatment method for the heat-conducting filler, i.e., component (C), an overall blending method, a dry concentration method, etc. can be used. The direct treatment method includes a dry method, a slurry method, a spray method, etc. The overall blending method includes a direct method, a masterbatch method, etc. Among them, the dry method, the slurry method, and the direct method are often used. The total amount of component (G) and component (C) can be pre-mixed using a known mixing device, and its surface can be treated. The foregoing 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 kneading mixer, a Henschel mixer, etc.

[0165] In a specific embodiment, before combining component (C) in its surface-treated form with the other components of the composition, component (C) is blended with both components (D) and (G) and surface-treated. Component (C) may optionally be incrementally blended with components (D) and (G) in the presence of a portion of component (A).

[0166] In certain embodiments, the composition further comprises an adhesion promoter. Suitable adhesion promoters may include alkoxysilanes such as alkoxysilanes, combinations of alkoxysilanes and hydroxy-functionalized polyorganosiloxanes, amino-functionalized silanes, epoxy-functionalized silanes, mercapto-functionalized silanes, or combinations thereof. Adhesion promoters are known in the art and may comprise silanes having the formula R 5 a R 6 b Si(OR 7 ) 4-(a+b) where each R 5 is independently a monovalent organic group having at least 3 carbon atoms; R 6 contains at least one SiC-bonded substituent having an adhesion-promoting group (such as an amino, epoxy, mercapto, or acrylate group); each R 7 is independently a monovalent organic group (e.g., methyl, ethyl, propyl, butyl, etc.); the subscript a has a value ranging from 0 to 2; the subscript b is 1 or 2; and the sum of (a + b) is not greater than 3. In certain embodiments, the adhesion promoter comprises a partial condensate of the above silanes. In these or other embodiments, the adhesion promoter includes a combination of an alkoxysilane and a hydroxy-functional polyorganosiloxane.

[0167] In some embodiments, the adhesion promoter includes an unsaturated compound or an epoxy-functional compound. In such embodiments, the adhesion promoter may be or include an unsaturated or epoxy-functionalized alkoxysilane, such as those having formula (XIII): R 8 cSi(OR 9 ) (4 -c ) where the subscript c is 1, 2, or 3, alternatively the subscript c is 1. Each R 8 is independently a monovalent organic group, provided that at least one R 8 is an unsaturated organic group or an epoxy-functionalized organic group. Epoxy-functionalized organic groups for R 8 are exemplified by 3-glycidoxypropyl and (epoxycyclohexyl)ethyl. Unsaturated organic groups for R 8 are exemplified by 3-methacryloxypropyl, 3-acryloxypropyl, and unsaturated monovalent hydrocarbon groups (such as vinyl, allyl, hexenyl, undecenyl). Each R9 Independently, a saturated hydrocarbon group having 1 to 4 carbon atoms, alternatively 1 to 2 carbon atoms. R 9 Illustrated by methyl, ethyl, propyl, and butyl.

[0168] 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, undecenyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-acryloxypropyltriethoxysilane, and combinations thereof.

[0169] In some embodiments, the adhesion promoter includes an epoxy-functionalized siloxane, such as the reaction product of a hydroxy-terminated polyorganosiloxane and an epoxy-functionalized alkoxysilane (e.g., such as one of the above alkoxysilanes), or a physical blend of a hydroxy-terminated polyorganosiloxane and an epoxy-functionalized alkoxysilane. The adhesion promoter can comprise a combination of an epoxy-functionalized alkoxysilane and an epoxy-functionalized siloxane. For example, examples of the adhesion promoter are a mixture of 3-glycidoxypropyltrimethoxysilane and the reaction product of a hydroxy-terminated methylvinylsiloxane and 3-glycidoxypropyltrimethoxysilane, or a mixture of 3-glycidoxypropyltrimethoxysilane and a hydroxy-terminated methylvinylsiloxane, or a mixture of 3-glycidoxypropyltrimethoxysilane and a hydroxy-terminated methylvinyl / dimethylsiloxane copolymer.

[0170] In certain embodiments, the adhesion promoter includes an amino-functionalized silane, optionally exemplified by: 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(CH2)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(OCH2CH3)2, H2N(CH2)3SiCH3(OCH3)2, H2N(CH2)3SiCH3(OCH2CH3)2, CH3NH(CH2)3SiCH3(OCH3)2, CH3NH(CH2)3SiCH3(OCH2CH3)2, CH3NH(CH2)5SiCH3(OCH3)2, CH3NH(CH2)5SiCH3(OCH2CH3)2, H2N(CH2)2NH(CH2)3SiCH3(OCH3)2, H2N(CH2)2NH(CH2)3SiCH3(OCH2CH3)2, CH3NH(CH2)2NH(CH2)3SiCH3(OCH3)2, CH3NH(CH2)2NH(CH2)3SiCH3(OCH2CH3)2, C4H9NH(CH2)2NH(CH2)3SiCH3(OCH3)2, C4H9NH(CH2)2NH(CH2)3SiCH3(OCH2CH3)2, N-(3-(trimethoxysilyl)propyl)ethylenediamine, and the like, and combinations thereof. In these or other embodiments, the adhesion promoter includes a thiol-functionalized alkoxysilane, such as 3-mercaptopropyltrimethoxysilane or 3-mercaptopropyltriethoxysilane.

[0171] Additional examples of adhesion promoters include reaction products of epoxyalkylalkoxysilanes (such as 3-glycidoxypropyltrimethoxysilane) and amino-substituted alkoxysilanes (such as 3-aminopropyltrimethoxysilane), optionally with alkylalkoxysilanes (such as methyltrimethoxysilane).

[0172] Exemplary adhesion promoters include reaction mixtures of organoalkoxysilanes containing amino groups and organoalkoxysilanes containing epoxy groups. Such reaction mixtures are disclosed in Japanese Patent Application Publication S52-8854 B and Japanese Unexamined Patent Application Publication H10-195085A, which are hereby incorporated by reference in their entireties.

[0173] In terms of molar ratio, the ratio of the alkoxysilane having an organic group containing an amino group to the alkoxysilane having an organic group containing an epoxy group is typically in the range of (1:1.5) to (1:5), alternatively in the range of (1:2) to (1:4). This component can be easily synthesized by mixing the alkoxysilane having an organic group containing an amino group and the alkoxysilane having an organic group containing an epoxy group as mentioned above and reacting them at room temperature or by heating.

[0174] In particular, when the alkoxysilane having an organic group containing an amino group reacts with the alkoxysilane having an organic group containing an epoxy group by the method described in Japanese Unexamined Patent Application H10-195085A, the present invention may include carbasilatrane derivatives obtained by cyclization through transesterification reaction and represented by the following general formula:

[0175]

[0176] wherein R 1 is an alkyl group, an alkenyl group or an alkoxy group, and R 2 is the same or different groups selected from the groups represented by the following general formula:

[0177]

[0178] wherein R 4 is an alkylene group or an alkyleneoxyalkylene group, R 5 is a monovalent hydrocarbon group, R 6 is an alkyl group, and a is 0, 1 or 2, or

[0179] -R 7 -O-R 8

[0180] wherein R 7 is an alkylene group, R 8 is an alkyl group, an alkenyl group or an acyl group, and R 3 is the same or different hydrogen atoms or alkyl groups. Examples of carbasilatrane derivatives may include carbasilatrane derivatives having a siloxane-bonded alkoxy group or a siloxane-bonded alkenyl group per molecule represented by the following structures.

[0181]

[0182] Wherein Rc is a group selected from a methoxy group, an ethoxy group, a vinyl group, an allyl group, and a hexenyl group.

[0183] In addition, in the present invention, a silatrane derivative represented by the following structural formula can be used as an adhesion promoter:

[0184]

[0185] Wherein R in the formula 1 is the same or different hydrogen atoms or alkyl groups, and R 1 is usually a hydrogen atom or a methyl group. In addition, R in the above formula 2 is the same or different group selected from the set consisting of a hydrogen atom, an alkyl group, and an organic group containing an alkoxysilyl group, represented by the following general formula:

[0186] -R 4 -Si(OR 5 ) x R 6 (3-x)

[0187] Wherein at least one of R 2 is an organic group containing an alkoxysilyl group. Examples of the alkyl group of R 2 include a methyl group and the like. In addition, in the organic group containing an alkoxysilyl group of R 2 , R in the formula 4 is a divalent organic group, and examples include an alkylene group or an alkyleneoxyalkylene group. Typically, an ethylene group, a propylene group, a butylene group, a methyleneoxypropylene group, and a methyleneoxypentylene group. In addition, R in the formula 5 is an alkyl group having 1 to 10 carbon atoms, and is usually a methyl group or an ethyl group. In addition, R in the formula 6 is a substituted or unsubstituted monovalent hydrocarbon group, and is usually a methyl group. In addition, x in the formula is 1, 2, or 3, and is usually 3.

[0188] R 2 Examples of such organic groups containing an alkoxysilyl group include the following groups.

[0189] -(CH2)2Si(OCH3)3-(CH2)2Si(OCH3)2CH3

[0190] -(CH2)3Si(OC2H5)3-(CH2)3Si(OC2H5)(CH3)2

[0191] -CH2O(CH2)3Si(OCH3)3

[0192] -CH2O(CH2)3Si(OC2H5)3

[0193] -CH2O(CH2)3Si(OCH3)2CH3

[0194] -CH2O(CH2)3Si(OC2H5)2CH3

[0195] -CH2OCH2Si(OCH3)3-CH2OCH2Si(OCH3)(CH3)2

[0196] When in use, based on the total weight of the composition, the adhesion promoter is present in the composition in an amount greater than 0% by weight to 3% by weight, alternatively 0.001% by weight to 2.0% by weight.

[0197] The curable silicone composition of the present invention may also comprise a filler and / or a pigment. When in use, the filler is different from the heat-conductive filler (C). The filler is not limited and may be, for example, a reinforcing filler, a compatibilizing filler, a conductive filler, a flame-retardant filler, an acid acceptor filler, a rheology-modifying filler, a phosphor, a coloring filler, a mineral filler, a glass filler, a carbon filler, or a combination thereof. The choice of filler is generally a function of the cured product to be formed from the composition and the end-use application of the cured product.

[0198] The filler may be untreated, pretreated, or added together with an optional filler treatment agent as described below, which when so added may treat the filler in situ or before incorporating the filler 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 the type of filler, the method of preparation, the treatment or surface chemistry, the filler composition, the filler shape, the filler surface area, the average particle size, or the particle size distribution.

[0199] The shape and size of the filler and / or pigment are also not particularly limited. For example, the filler may be spherical, rectangular, oval, irregular in shape, and may be in the form of, for example, powder, flour, fiber, flake, chip, shaving, strand, scrim, wafer, wool, straw, granule, and combinations thereof. The size and shape are generally selected based on the type of filler utilized, the choice of other components included in the composition, and the end-use application of the cured product formed therewith.

[0200] Non-limiting examples of fillers that can be used 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 and is commercially available; for example, fumed silica sold under the trade name CAB-O-SIL by Cabot Corporation of Massachusetts, U.S.A.

[0201] Non-limiting examples of fillers that can be used as compatibilizing or reinforcing fillers include quartz and / or ground quartz, alumina, magnesia, silica (e.g., fumed, milled, precipitated silica), magnesium silicate hydrate, magnesium carbonate, dolomite, silicone resin, wollastonite, steatite, kaolin, china clay, muscovite mica, phlogopite mica, halloysite (hydrated aluminum silicate), aluminum silicate, sodium aluminum silicate, glass (fibers, beads or particles, including recycled glass, e.g., from wind turbines or other sources), clay, magnetite, hematite, calcium carbonate (such as precipitated, fumed and / or ground calcium carbonate), calcium sulfate, barium sulfate, calcium metasilicate, zinc oxide, talc, diatomaceous earth, iron oxide, clay, mica, chalk, titanium dioxide, zirconium oxide, sand, carbon black, graphite, anthracite, coal, lignite, charcoal, activated carbon, non-functionalized silicone resin, alumina, silver, metal powder, magnesia, magnesium hydroxide, magnesium oxysulfate fiber, aluminum trihydroxide, aluminum hydroxide, coated fillers, carbon fiber (including recycled carbon fiber, e.g., from the aircraft and / or automotive industries), aromatic polyamide (such as chopped KEVLAR TM or TWARON TM ), nylon fiber, mineral fillers or pigments (e.g., titanium dioxide, anhydrous, 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); rice husk ash, ceramics and zeolites, metals (such as aluminum flakes or powder, bronze powder, copper, gold, molybdenum, nickel, silver powder or flakes), stainless steel powder, tungsten, barium titanate, silica-carbon black composite, functionalized carbon nanotubes, cement, slate powder, pyrophyllite, sepiolite, zinc stannate, zinc sulfide) and combinations thereof. Alternatively, the compatibilizing or reinforcing filler can be selected from the group consisting of calcium carbonate, talc, and combinations thereof.

[0202] As is known in the art, certain fillers can be used 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 spheres, glass beads, etc.; and additionally, barium sulfate, zinc sulfate, barium titanate, aluminum nitride, boron nitride, and antimony oxide. Such components can be considered fillers and / or pigments.

[0203] Compatibilizing fillers are known in the art and are commercially available; such as ground silica sold under the trade name MIN-U-SIL by U.S. Silica of Berkeley Springs, WV. Suitable precipitated calcium carbonates include WINNOFIL TM SPM from Solvay and ULTRA-PFLEX TM and ULTRA-PFLEX TM 100.

[0204] Alternatively or in addition, the filler can include non-reactive silicone resins. For example, the filler can include T resins, TD resins, TDM resins, TDMQ resins, or any other non-reactive silicone resin. Generally, such non-reactive silicone resins include at least 30 mole % of T siloxy and / or Q siloxy units. As is known in the art, D siloxy units are represented by R 0 2SiO 2 / 2 and T siloxy units are represented by R 0 SiO 3 / 2 where R 0 is an independently selected substituent.

[0205] The weight average molecular weight M w of the non-reactive silicone resin will depend at least in part on the molecular weight of the silicone resin and the type of substituent (e.g., hydrocarbon group) present in the non-reactive silicone resin. As used herein, M w represents the weight average molecular weight measured using conventional gel permeation chromatography (GPC), calibrated using narrow molecular weight distribution polystyrene (PS) standards when the peak representing the new pentamer is excluded from the measurement. The PS equivalent M w of the non-reactive silicone resin can be from 12,000 g / mole to 30,000 g / mol, typically from 17,000 g / mole to 22,000 g / mol. The non-reactive silicone resin can be prepared by any suitable method. This type of silicone resin has been prepared by co-hydrolysis of the corresponding silanes or by capping silica hydrosols commonly known in the art.

[0206] A phosphor is a filler of this type that can convert the emission wavelength from a light source (an optical semiconductor device) when the cured product of the composition is used as a wavelength conversion material. Such a phosphor is not particularly limited, and examples of the phosphor include yellow, red, green, and blue phosphors, including oxide phosphors, oxynitride phosphors, nitride phosphors, sulfide phosphors, oxysulfide phosphors, etc., which are widely used in light-emitting diodes (LEDs).

[0207] In certain embodiments, the filler can include an acid acceptor. The acid acceptor can include metal oxides such as magnesium oxide. Acid acceptors are generally known in the art and can be commercially obtained under trade names including Rhenofit F, Star Mag CX-50, Star Mag CX-150, BLP-3, and MaxOx98LR. Rhenofit F is calcium oxide purchased from Rhein Chemie Corporation of Shardon, Ohio, USA. Star Mag CX-50 is magnesium oxide purchased from Merrand International Corp. of Portsmouth, New Hampshire, USA. MagOX98LR is magnesium oxide purchased from Premier Chemicals LLC of West Conshohocken, Pennsylvania, USA. BLP-3 is calcium carbonate purchased from Omya Americas of Cincinnati, Ohio, USA.

[0208] Regardless of the choice of filler, the filler can be untreated, pretreated, or added with an optional filler treatment agent to form the composition, and the filler treatment agent can treat the filler in situ in the composition when added in this way.

[0209] The filler treatment agent can include silanes (such as alkoxysilanes), alkoxy-functionalized oligosiloxanes, cyclic polyorganosiloxanes, hydroxy-functionalized oligosiloxanes (such as dimethylsiloxane or methylphenylsiloxane), organosilicon compounds, stearates, or fatty acids. The filler treatment agent can include a single filler treatment agent or a combination of two or more filler treatment agents selected from similar or different types of molecules.

[0210] The filler treatment agent may include alkoxysilanes, which may be monoalkoxysilanes, dialkoxysilanes, trialkoxysilanes or tetraalkoxysilanes. Examples of alkoxysilane filler treatment agents are: hexyltrimethoxysilane, octyltriethoxysilane, decyltrimethoxysilane, dodecyltrimethoxysilane, tetradecyltrimethoxysilane, phenyltrimethoxysilane, phenethyltrimethoxysilane, octadecyltrimethoxysilane, octadecyltriethoxysilane, and combinations thereof. In some aspects, the alkoxysilane may be used in combination with silazanes, which can catalyze the reaction of less reactive alkoxysilanes with surface hydroxyl groups. Such reactions are typically carried out above 100 °C with high shear force and in the presence of removal of volatile by-products such as ammonia, methanol, and water.

[0211] Suitable filler treatment agents also include alkoxysilyl-functionalized alkyl methyl polysiloxanes, or similar materials in which the hydrolyzable group may include, for example, silazanes, acyloxy groups, or oxime groups.

[0212] Alkoxy-functionalized oligomeric siloxanes can also be used as filler treatment agents. Alkoxy-functionalized oligomeric siloxanes and their preparation methods are well known in the art. Other filler treatment agents include monofunctionalized alkoxy-functionalized polydiorganosiloxanes, i.e., polyorganosiloxanes having an alkoxy functional group at one end.

[0213] Alternatively, the filler treatment agent can be any silicone compound commonly used to treat silica fillers. Examples of silicone compounds include organochlorosilanes such as methyltrichlorosilane, dimethyldichlorosilane, and trimethylchlorosilane; siloxanes such as hydroxy-terminated dimethylsiloxane oligomers, hydrosilicon-functionalized siloxanes, hexamethyldisiloxane, and tetramethyldivinyldisiloxane; silazanes such as hexamethyldisilazane and hexamethylcyclotrisilazane; and organoalkoxysilanes such as alkylalkoxysilanes having methyl, propyl, n-butyl, isobutyl, n-hexyl, n-octyl, isooctyl, n-decyl, dodecyl, tetradecyl, hexadecyl, or octadecyl substituents. The organoreactive alkoxysilane can include amino, methacryloxy, vinyl, glycidyloxy, epoxycyclohexyl, isocyanurate, isocyanate, mercapto, thio, vinyl-benzyl-amino, benzyl-amino, or phenyl-amino substituents. Alternatively, the filler treatment agent can include organopolysiloxanes. Treating the surface of the filler with such a filler treatment agent can utilize multiple hydrogen bonds (clustered or dispersed or both) as a method of bonding the siloxane to the surface of the filler. The siloxane capable of hydrogen bonding has an average of at least one silicon-bonded group capable of hydrogen bonding per molecule. The group can be selected from: a monovalent organic group having multiple hydroxyl functional groups or a monovalent organic group having at least one amino functional group. Hydrogen bonding can be the primary mode of bonding the siloxane to the filler. The siloxane may not be able to form a covalent bond with the filler. The siloxane capable of hydrogen bonding can be selected from the group consisting of sugar-siloxane polymers, amino-functionalized siloxanes, and combinations thereof. Alternatively, the polyorganosiloxane capable of hydrogen bonding can be a sugar-siloxane polymer.

[0214] Alternatively, the filler treatment agent can include alkylthiols (such as octadecyl mercaptan, etc.) and fatty acids (such as oleic acid, stearic acid), titanates, titanate coupling agents, zirconate coupling agents, and combinations thereof. Those skilled in the art can optimize the filler treatment agent to assist in filler dispersion without undue experimentation.

[0215] If used, the relative amounts of the filler treatment agent and the filler are selected based on the specific filler used and the desired effects or properties of the filler treatment agent and them.

[0216] In certain embodiments, the composition further comprises an inhibitor. The inhibitor can be used to change the reaction rate or curing rate of the composition as compared to a composition that contains the same starting materials but omits the inhibitor. The inhibitor is exemplified by alkynols such as methyl butynol, ethynyl cyclohexanol, dimethyl hexynol, and 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; cycloalkenyl siloxanes such as methyl vinyl cyclo siloxanes exemplified by 1,3,5,7-tetramethyl-1,3,5,7-tetravinyl cyclotetrasiloxane, 1,3,5,7-tetramethyl-1,3,5,7-tetrahydrohexenyl cyclotetrasiloxane and combinations thereof; enyne compounds such as 3-methyl-3-penten-1-yne, 3,5-dimethyl-3-hexen-1-yne; triazoles such as benzotriazole; phosphines; thiols; hydrazines; amines such as tetramethylethylenediamine; dialkyl fumarates, diene fumarates, dialkoxyalkyl fumarates; maleates such as diallyl maleate; nitriles; ethers; carbon monoxide; olefins such as cyclooctadiene, divinyltetramethyldisiloxane; alcohols such as benzyl alcohol; and combinations thereof. Alternatively, the inhibitor can be selected from the group consisting of alkynols (e.g., 1-ethynyl-1-cyclohexanol) and maleates (e.g., diallyl maleate, bismaleate or n-propyl maleate) and combinations of two or more of them.

[0217] Alternatively, the inhibitor can be a silylated alkynyl compound. Without wishing to be bound by theory, it is believed that the addition of a silylated alkynyl compound reduces the yellowing of the reaction product prepared by the hydrosilylation reaction of the composition as compared to the reaction product obtained by hydrosilylation of a composition that does not contain a silylated alkynyl compound or contains an organic alkynol inhibitor (e.g., those described above).

[0218] Examples of silylated acetylenic compounds include (3-methyl-1-butyn-3-yloxy)trimethylsilane, ((1,1-dimethyl-2-propynyl)oxy)trimethylsilane, bis(3-methyl-1-butyn-3-yloxy)dimethylsilane, bis(3-methyl-1-butyn-3-yloxy)silane methylvinylsilane, bis((1,1-dimethyl-2-propynyl)oxy)dimethylsilane, methyl(tris(1,1-dimethyl-2-propynyloxy))silane, methyl(tris(3-methyl-1-butyn-3-yloxy))silane, (3-methyl-1-butyn-3-yloxy)dimethylphenylsilane, (3-methyl-1-butyn-3-yloxy)dimethylhexenylsilane, (3-methyl-1-butyn-3-yloxy)triethylsilane, bis(3-methyl-1-butyn-3-yloxy)methyltrifluoropropylsilane, (3,5-dimethyl-1-hexyn-3-yloxy)trimethylsilane, (3-phenyl-1-butyn-3-yloxy)diphenylmethylsilane, (3-phenyl-1-butyn-3-yloxy)dimethylphenylsilane, (3-phenyl-1-butyn-3-yloxy)dimethylvinylsilane, (3-phenyl-1-butyn-3-yloxy)dimethylhexenylsilane, (cyclohexyl-1-ethyn-1-yloxy)dimethylhexenylsilane, (cyclohexyl-1-ethyn-1-yloxy)dimethylvinylsilane, (cyclohexyl-1-ethyn-1-yloxy)diphenylmethylsilane, (cyclohexyl-1-ethyn-1-yloxy)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 combinations thereof. The silylated acetylenic compounds useful as inhibitors can be prepared by methods known in the art, such as by reacting the above-mentioned alkynols with chlorosilanes in the presence of an acid acceptor to silylate the above-mentioned alkynols.

[0219] The amount of inhibitor present in the composition will depend on various factors, including the desired shelf life of the composition, whether the composition will be a one-component or multi-component composition, the specific inhibitor used, and the selection and amount of components (A)-(G). However, when present, based on the total weight of the composition, the amount of inhibitor (D) can be 0% to 1%, alternatively 0% to 5%, alternatively 0.001% to 1%, alternatively 0.01% to 0.5%, and alternatively 0.0025% to 0.025%.

[0220] In some embodiments, the composition further comprises a heat resistance improver other than component (G). Other resistance improvers are exemplified by iron oxide (red iron oxide), cerium oxide, dimethylsilanol cerium, cerium fatty acid salts, cerium hydroxide, zirconium compounds, copper (Cu) phthalocyanine, or combinations thereof.

[0221] In addition to the above components, optional components can be blended into the thermally conductive silicone composition of the present invention within the range that does not impair the object of the present invention. Examples of the optional components include inorganic fillers (also referred to as "inorganic filling 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 hydrophobically treating the surface of such inorganic fillers with a silicone compound; 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. In addition, in the thermally conductive silicone gel composition of the present invention, if necessary, at least one type of antistatic agent can be included, and the antistatic agent includes known adhesion imparting agents, cationic surfactants, anionic surfactants, or nonionic surfactants; dielectric fillers; conductive fillers; release components; thixotropy imparting agents; antifungal agents; etc. If necessary, an organic solvent can also be added.

[0222] However, in certain embodiments, the composition is substantially free, alternatively does not contain, an organic solvent. With respect to the composition being substantially free of an organic solvent, "substantially free" means that the composition contains an amount of organic solvent that is 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 less than 0% by weight, based on the total weight of the composition.

[0223] Examples of organic solvents that are not normally present in the composition include organic oils, which include volatile and / or semi-volatile hydrocarbons, esters, and / or ethers. General examples of such organic fluids include volatile hydrocarbon oils, such as C6-C 16 alkanes, C8-C 16 isoparaffins (e.g., isodecane, isododecane, isocetane, etc.), C8-C 16 branched esters (e.g., isohxyl neopentanoate, isodecyl neopentanoate, etc.), etc. and their derivatives, modified products, and combinations. Additional examples of suitable organic fluids include aromatic hydrocarbons (such as benzene, toluene, and xylene), aliphatic hydrocarbons (such as heptane, hexane, and octane), alcohols having more than 3 carbon atoms, aldehydes, ketones (such as acetone, methyl ethyl ketone, and methyl isobutyl ketone), amines, esters, ethers, diols, diol ethers, alkyl halides, aromatic halides, and their combinations. Hydrocarbons include isododecane, isocetane, Isopar L (C 11 -C 13 ), Isopar H (C 11 -C 12) Hydrogenated polydecene. Ethers and esters include isodecyl neopentanoate, neopentyl glycol heptanoate, diol distearate, dioctyl 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), octadecyl neopentanoate, diisobutyl adipate, diisopropyl adipate, propylene glycol dicaprylate / dicaprate, octyl ether, octyl palmitate, and combinations thereof.

[0224] The composition can be cured to obtain a cured product in the form of a silicone gel having excellent physical properties, including crack resistance when exposed to elevated temperatures for an extended period. Because the occurrence of bubbles and cracks can be inhibited, the silicone gel has excellent adhesion properties to electrical or electronic parts.

[0225] The composition of the present invention can be prepared by mixing each of the above components. For example, it can be prepared by first mixing components (C) and (D), optionally with component (E) (if present), then treating the surface of component (C) with components (D) and (E) (if present), and then mixing the remaining components and other optional components. Alternatively, the composition can be prepared by mixing components (C) and (D) (and optional (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 usually combined to obtain component (B) before combining component (B) with other components. The method for mixing each component can be a conventionally known method and is not particularly limited. However, it is generally preferred to use a mixing device to mix the components because a uniform mixture can be obtained by simple stirring. This mixing device is not particularly limited, and examples thereof include single-axis or double-axis continuous mixers, two-roll mills, Ross mixers, Hobart mixers, dental mixers, planetary mixers, kneading mixers, Henschel mixers, etc.

[0226] The composition of the present invention can be used as a one-component composition (including single-package types), or, if necessary, also as a multi-component composition (including multi-package types, especially two-package types), where the separate multi-components are mixed during use. In the case of a one-component type, each component of the composition can be used by being placed in a single storage container. In the case of a multi-component type, a plurality of separately stored compositions can be mixed and used at a predetermined ratio. It should be noted that these packages are not particularly limited and can be selected as needed according to the curing method, coating method, and application items described later.

[0227] The composition of the present invention has excellent fluidity, can be precisely coated, and has excellent gap filling ability. Specifically, the viscosity of the composition before curing is in the range of 10 Pa·s to 500 Pa·s at 25°C, and more typically in the range of 50 Pa·s to 400 Pa·s at 25°C.

[0228] The composition of the present invention cures by a hydrosilylation reaction to form a silicone cured product having excellent thermal conductivity and adhesiveness. The temperature for curing the hydrosilylation reaction-curable silicone gel composition is not particularly limited. Surprisingly, the composition is capable of curing at room temperature, which is particularly advantageous for many end-use applications. If desired, elevated temperatures in the range of 20°C to 150°C, alternatively 20°C to 80°C, can be utilized to accelerate curing.

[0229] The hardness of the silicone cured product of the present invention preferably satisfies the range of 10 to 70, and more preferably satisfies the range of 15 to 60; the hardness is measured according to JIS Type A. Further, even after heating the silicone cured product at 200°C for 72 hours, its hardness is still less than 80 (measured according to JIS Type A).

[0230] The composition of the present invention can be stably and highly filled with a heat conductive filler, whereby a composition and a silicone gel cured product having a thermal conductivity of 2.0 W / mK or greater, alternatively 3.0 W / mK or greater, alternatively 3.0 W / mK to 7.0 W / mK can be designed.

[0231] The composition of the present invention can be used as an interface that can be inserted between a heat generating component and a heat dissipation member such as a radiator or a circuit board for conduction cooling of the heat generating component (heat conductive member), and a heat dissipation structure containing the same can be formed. Here, the type, size, and detailed structure of the heat generating component are not particularly limited, but the heat conductive silicone gel composition of the present invention has high thermal conductivity while having excellent gap filling ability for components, high adhesiveness and followability even for heat generating members having fine irregularities and narrow gap structures, and has the flexibility inherent to a gel. Therefore, the heat conductive silicone gel composition can be applied to heat dissipation structures of electrical / electronic devices including electrical / electronic components or battery-type secondary batteries.

[0232] The electrical / electronic device including a member composed of the above-described thermally conductive silicone composition is not particularly limited. Examples thereof include secondary batteries such as battery-type lithium-ion electrode secondary batteries and battery stack fuel cells; electronic circuit boards such as printed circuit boards; IC chips packaged with optical semiconductor devices such as diodes (LEDs), organic electroluminescent elements (organic ELs), laser diodes, and LED arrays; electronic devices such as CPUs used in personal computers, digital video discs, mobile phones, and smart phones; LSI chips such as driver ICs and memories; and the like. In particular, in high-performance digital switching circuits formed with a high integration density, heat removal (heat dissipation) becomes a key factor in the performance and reliability of integrated circuits. However, the thermally conductive member using the thermally conductive silicone gel composition of the present invention has excellent heat dissipation and handleability even when applied to power semiconductor applications such as engine control, power train, and air-conditioning control in air transportation; and has excellent heat resistance and thermal conductivity even when used in a harsh environment built in in-vehicle electronic parts such as electronic control units (ECUs). In addition, the thermally conductive silicone gel composition according to the present invention can be disposed not only on a horizontal surface but also on a vertical surface by controlling its rheology, and it can also penetrate into the microstructure of heat-generating components such as electrical / electronic components or secondary batteries to provide a heat dissipation structure without gaps. Therefore, heat dissipation of the electrical / electronic device including the heat dissipation structure can be improved; latent heat and thermal runaway problems can be improved, while the flexible gel-like cured product can protect the sub-structure of the electrical / electronic device, thereby improving its reliability and operation stability.

[0233] Examples of the material constituting the above-described electrical / electronic device include resins, ceramics, glass, and metals (such as aluminum). The thermally conductive silicone composition of the present invention can be applied to a substrate either as a thermally conductive silicone gel composition (fluid) before curing or as a thermally conductive silicone cured product.

[0234] For the heat-generating component, the method of forming a heat dissipation structure using the thermally conductive silicone gel composition of the present invention is not limited, and examples include a method of pouring the thermally conductive silicone gel composition of the present invention into a heat dissipation part of an electrical / electronic component, sufficiently filling the gap, and then placing it at room temperature or optionally heating to cure the composition.

[0235] In applications where rapid curing is required, the method of heating and curing is particularly preferred because the entire material can be cured relatively quickly. At this time, the increase in the heating temperature promotes the generation of bubbles and cracks in the sealant for electrical / electronic components to be sealed or filled. Therefore, it is preferably heated in the range of 50°C to 250°C; particularly preferably in the range of 70°C to 130°C. In the case of thermal curing, a single-package type of package can be formed. In this case, from the viewpoints of improving the handleability of the composition and the pot life, a platinum hydrosilylation reaction catalyst dispersed or encapsulated in a thermoplastic resin in the form of particles can be used and is preferred.

[0236] 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 formed into a single-package type or a multi-package type of package. And, after mixing, it is preferably cured at room temperature or by heating at 50°C or lower for 1 hour to several days.

[0237] The shape, thickness, and arrangement of the thermally conductive silicone gel obtained by the above curing can be designed as needed. It can be cured as needed after filling the gap of an electrical / electronic device, or it can be applied or cured on a film provided with a release layer (separator), or it can be treated separately as a cured product of the thermally conductive silicone gel on the film. In addition, in this case, the shape of a thermally conductive sheet reinforced by a known reinforcing material can also be used.

[0238] The thermally conductive silicone gel composition of the present invention has excellent gap-filling ability and forms a gel-like thermally conductive member having excellent flexibility and thermal conductivity. Therefore, it is also effective for those between an electrical component and a package, between electrical components, and between electrodes in an electrical / electronic component having a narrow gap, and those having a structure in which the above structure is difficult to follow the expansion and contraction of the silicone gel. For example, it can also be used for semiconductor devices such as secondary batteries, ICs, hybrid ICs, and LSIs; electronic circuits and modules equipped with such semiconductor devices, capacitors, resistors, and other electrical components; various sensors such as pressure sensors; igniters and regulators for automobiles, power generation systems, or power devices such as space transportation systems.

[0239] The following examples are intended to illustrate the present invention and should not be construed in any way as limiting the scope of the present invention.

[0240] Some of the components used in the examples are listed in Table 1 below.

[0241] The following examples are intended to illustrate the present invention and should not be construed in any way as limiting the scope of the present invention.

[0242] Some of the components used in the examples are listed in Table 1 below.

[0243] Table 1:

[0244]

[0245]

[0246] Preparation Examples 1 and 2

[0247] Prepare Base Compositions 1 and 2 for preparing the compositions in the subsequent examples. Table 2 below shows the amounts of each component present in Base Compositions 1 and 2 prepared as in Preparation Examples 1 and 2. The values in Table 2 are parts by weight, with the sum of each of Base Compositions 1 and 2 being 95 parts by weight. Base Compositions 1 and 2 may alternatively be referred to as masterbatches.

[0248] Table 2:

[0249]

[0250] General Procedure 1: Preparation Examples 1 and 2

[0251] Prepare Base Compositions 1 and 2 according to General Procedure 1. In General Procedure 1, the organopolysiloxane (A-1), the siloxane macromonomer (D), and the alkoxysilane (G) (if used) are placed in a 1 L planetary mixer. Then, the fillers (C-1) and (C-2) are placed in the mixer and mixed at room temperature for 10 minutes. Then, half of the amount of the filler (C-4) used is placed in the mixer, followed by mixing at room temperature for another 10 minutes. Then, the remaining half of the filler (C-4) used is placed in the mixer, followed by scraping and further mixing at room temperature for 10 minutes.

[0252] Examples 1 to 9 and Comparative Examples 1 to 4

[0253] The 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. Unless otherwise specified, the values in Tables 3 and 4 are parts by weight. The SiH / Vi molar ratios reported for each composition below do not include the inhibitor and Component (E).

[0254] Table 3: Examples 1 - 7

[0255]

[0256] Table 4: Examples 8 - 9 and Comparative Examples 1 - 4

[0257]

[0258]

[0259] General Procedure 2: Examples 1 - 9 and Comparative Examples 1 - 4

[0260] The compositions of Examples 1-9 and Comparative Examples 1-4 were prepared according to General Procedure 2. In General Procedure 2, the 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. Then, the remaining components except the catalyst (E) were placed in a planetary mixer, and the contents of the mixer were mixed at room temperature for 15 minutes. The contents were removed from the mixture, mixed with the catalyst (E), and degassed for 3 minutes. Then, the composition was cured to obtain a heat-conductive member, and the physical properties were measured as described below.

[0261] Hardness

[0262] The hardness of each heat-conductive member was measured using a JIS A-type hardness tester. Specifically, a mold with a plate size of 120 mm × 120 mm × 2 mm was used, with PTFE sheets between each plate of the mold. Each composition was placed in the mold to form a sheet with a thickness of 2 mm, and cured in a hot press at 120 °C for 60 minutes, followed by measuring the JIS A-type hardness using a JIS A-type hardness tester. The hardness was measured by stacking three sheets on top of each other. The hardness of each heat-conductive member was also measured after aging at 200 °C for 72 hours.

[0263] Thermal conductivity (hot disk)

[0264] The thermal conductivity of each heat-conductive member was measured via a hot disk. More specifically, a test piece of the heat-conductive member was prepared in a mold with a plate size of 50 mm × 30 mm × 6 mm, with PTFE sheets 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. Then, the thermal conductivity of two samples was measured using a Hot Disk TPS 500S from HotDisk AB in Goteborg, Sweden, and the average value was taken and reported below.

[0265] Lap shear strength and cohesive failure rate

[0266] The adhesive strength (MPa) and the cohesive failure rate (%) of each heat-conductive member were measured by first cleaning the aluminum die-cast substrate (ADC12) with isopropyl alcohol. Each composition was filled into the overlapping area defined by the aluminum die-cast substrate having dimensions of 10 mm × 24 mm × 1 mm. When placed in the overlapping area defined by the substrate, each composition was cured in a hot press at 120 °C for 60 minutes. After curing, the excess cured product was removed from the periphery of the overlapping area via a cutter, and the properties were measured via a tensile test at a measurement speed of 50 mm / min.

[0267] Tables 5 and 6 below show the physical properties measured for the heat-conductive members formed from the respective compositions of Examples 1-9 and Comparative Examples 1-4.

[0268] Table 5: Examples 1 - 7

[0269]

[0270] Table 6: Examples 8 - 9 and Comparative Examples 1 - 4

[0271]

Claims

1. A thermally conductive silicone composition, the thermally conductive silicone composition comprising: (A) 100 parts by mass of an alkenyl group-containing organopolysiloxane having a viscosity of 10 mPa·s to 100,000 mPa·s at 25°C; (B) A mixture of components (B1) and (B2): (B1) An organosilicon compound having 1 to 100 silicon atoms, the organosilicon compound containing at least one phenylene structure and at least one silicon-bonded hydrogen atom per molecule, and (B2) an organohydrogenpolysiloxane containing an average of 2 to 4 silicon-bonded hydrogen atoms per molecule and having a viscosity of 1 mPa·s to 1,000 mPa·s at 25°C but not containing a phenylene structure in the molecule, wherein the total amount of silicon-bonded hydrogen atoms in component (B) is 0.5 mol to 1.1 mol per 1 mol 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 parts by mass 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-[(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, R 1 , R 2 and R 3 are independently selected from alkyl groups having 1 to 20 carbon atoms, alkenyl groups having 2 to 4 carbon atoms, alkoxy groups 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 both 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) wherein R 5 and R 6 are alkyl groups 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. The thermally conductive organosilicon composition according to claim 1, further comprising: (F) A heat resistance imparting agent.

3. The thermally conductive silicone composition according to claim 1 or claim 2, the thermally conductive silicone composition further comprising: (G) An alkoxysilane having an alkyl group with 6 or more carbon atoms.

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

5. The thermally conductive organosilicon composition according to claim 1, wherein the composition substantially does not contain an organic solvent.

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

7. The thermally conductive silicone composition according to claim 1, wherein the composition is a heat curable thermally conductive silicone composition.

8. A thermally conductive member, the thermally conductive member comprising the thermally conductive silicone composition according to claim 1.

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

10. A heat dissipation structure, the heat dissipation structure comprising the thermally conductive member according to claim 8 or 9.

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

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

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