Thermally conductive silicone adhesive composition

Abstract

The present invention comprises (A) an alkenyl group-containing organopolysiloxane; (B) an organohydrogenpolysiloxane having, on average, at least two hydrogen atoms directly bonded to silicon atoms per molecule; (C) a thermally conductive filler; (D) a silane coupling agent; and (E) a catalyst, wherein component (D) is selected from the group consisting of compounds represented by the following general formulas (i) to (iii) and mixtures thereof: [Formula 1] TIFF2025535558000020.tif44154 [In each formula, R1 independently represents hydrogen or a vinyl group, and R2 independently represents an alkyl group having 1 to 4 carbon atoms; and component (D) is present in an amount of less than 1 wt %, based on the total weight of the composition. The present invention is characterized by a favorable combination of properties, including good flowability and high thermal conductivity upon curing.

Description

[Technical Field]

[0001] Technical Field The present invention relates to a thermally conductive silicone adhesive composition, and in particular to a thermally conductive silicone adhesive composition that has good flowability and exhibits high thermal conductivity when cured, as well as a method for producing the same and uses thereof. [Background technology]

[0002] Background of the Invention In recent years, the miniaturization and high performance of electronic devices have led to an increasing demand for heat-dissipating compositions. Thermally conductive silicone adhesive compositions with good fluidity and high thermal conductivity are widely used in electronic devices, especially telecommunications and data communication devices such as 5G stations.

[0003] Examples of such thermally conductive silicone adhesive compositions include those containing a vinyl-containing organopolysiloxane, an organohydrogenpolysiloxane, a thermally conductive filler, an adhesion promoter selected from epoxysilanes or alkyl titanates, and a platinum-based catalyst. To improve the thermal conductivity of the cured product obtained from such a thermally conductive silicone adhesive composition, it is necessary to incorporate a large amount of thermally conductive filler into the composition. However, increasing the amount of such filler impairs the fluidity of the composition, causing clogging of the nozzles of conventional adhesive dispensers.

[0004] US 2020 / 0157350A1 discloses a thermally conductive polysiloxane composition comprising: (A) a thermally conductive filler; (B) a polyorganosiloxane resin having a curable functional group in the polysiloxane molecule, the polyorganosiloxane resin including at least one polysiloxane (b1) having one curable functional group in the molecule; (C) a siloxane compound having an alkoxysilyl group and a linear siloxane structure; (D) a hydrogen polyorganosiloxane; and (E) a platinum catalyst, wherein the content of polysiloxane (b1) having one curable functional group in the molecule in the polyorganosiloxane resin (B) is greater than 80% by mass.

[0005] WO2019 / 021825A1 discloses a process for producing a polysiloxane comprising: (A) 100 parts by mass of an alkenyl group-containing organopolysiloxane having a viscosity of 10 to 100,000 mPa·s at 25°C; (B) an organohydrogenpolysiloxane in an amount such that the number of silicon-bonded hydrogen atoms in component (B) is 0.2 to 5 moles per mole of alkenyl groups in component (A); (C) a catalytic amount of a hydrosilylation reaction catalyst; and (D) 1,200 to 7,500 parts by mass of both of the above. Disclosed is a thermally conductive silicone gel composition comprising: a thermally conductive filler; (E) one or more silane coupling agents or hydrolysis condensates thereof; and (F) an organopolysiloxane having a specific structure, wherein when the total mass of component (D) in the composition is taken as 100 mass%, the combined amount of components (E) and (F) is 0.1 to 5.0 mass%, and the mass ratio of components (E) to (F) is in the range of 5:95 to 95:5.

[0006] US20180134938A1 discloses a thermally conductive composition that has good thermal conductivity, low viscosity, and is easy to apply, and that contains (A) a spherical thermally conductive filler and (B) an alkoxysilane compound or dimethylpolysiloxane. The spherical thermally conductive filler of component (A) is a mixture of fillers having different average particle sizes blended in a specific ratio, and the mixture contains 30% by mass or more of spherical thermally conductive fillers made from nitrides having an average particle size of 50 μm or more. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] U.S. Patent Application Publication No. 2020 / 0157350 [Patent Document 2] International Publication No. 2019 / 021825 [Patent Document 3] US Patent Application Publication No. 20180134938 Summary of the Invention [Problem to be solved by the invention]

[0008] However, the thermal conductivity of the compositions disclosed above is 10 W / (m·K) or less, which cannot meet the increasing demand for heat dissipation performance.

[0009] In view of the above, it is an object of the present invention to provide a thermally conductive silicone adhesive composition that has a favorable combination of properties including good flowability (greater than 15 g / min at 25°C) and high thermal conductivity after cure (greater than 10 W / (m·K)). [Means for solving the problem]

[0010] Summary of the Invention In this specification, (A) an alkenyl group-containing organopolysiloxane; (B) an organohydrogenpolysiloxane having, on average, at least two hydrogen atoms directly bonded to silicon atoms per molecule; (C) thermally conductive filler; (D) a silane coupling agent; and (E) Catalyst A thermally conductive silicone adhesive composition comprising: wherein component (D) is selected from the following general formulae (i) to (iii) and mixtures thereof: [ka] [In each formula, R 1は R independently represents hydrogen or a vinyl group. 2は each independently represents an alkyl group having 1 to 4 carbon atoms. Also, component (D) is present in an amount of less than 1 weight percent, based on the total weight of the composition. A thermally conductive silicone adhesive composition is disclosed.

[0011] Also disclosed herein is a method for preparing the thermally conductive silicone adhesive composition according to the present invention.

[0012] Also disclosed are cured products of the thermally conductive silicone adhesive compositions of the present invention.

[0013] Also disclosed herein are thermally conductive silicone adhesive compositions and the use of cured products of the thermally conductive silicone adhesive compositions according to the present invention in the manufacture of electronic devices.

[0014] Other features and aspects of the present subject matter are described in further detail below. DETAILED DESCRIPTION OF THE INVENTION

[0015] Detailed Description of the Invention Those skilled in the art will appreciate that the present invention is merely a description of exemplary embodiments and is not intended to limit the broader aspects of the present invention. Each aspect so described may be combined with other aspects unless expressly indicated to the contrary. In particular, any feature indicated as being preferred or advantageous may be combined with any other feature indicated as being preferred or advantageous.

[0016] Unless otherwise specified, in the context of the present invention, the terms used shall be construed in accordance with the following definitions.

[0017] Unless otherwise specified, the terms "a," "an," and "the" as used herein include both the singular and the plural.

[0018] As used herein, the terms "comprising" and "comprises" are synonymous with "including," "includes," or "containing," and "contains," and are inclusive or open-ended and do not exclude additional, unlisted members, elements, or process steps.

[0019] As used herein, the term "room temperature" refers to a temperature of about 20°C to about 25°C, preferably about 25°C.

[0020] Molecular weight refers to weight average molecular weight (Mw) unless otherwise specified. All molecular weight data refer to values ​​obtained by gel permeation chromatography (GPC), unless otherwise specified, such as DIN 55672.

[0021] Unless otherwise specified, the recitation of numerical endpoints includes not only the recited endpoint but also all numerical values ​​and fractions within each range.

[0022] All references cited herein are incorporated by reference in their entirety.

[0023] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the meaning commonly understood by one of ordinary skill in the art to which this invention belongs.

[0024] In one aspect, the present disclosure generally relates to a thermally conductive silicone adhesive composition comprising: (A) an alkenyl group-containing organopolysiloxane; (B) an organohydrogenpolysiloxane having, on average, at least two hydrogen atoms directly bonded to silicon atoms per molecule; (C) thermally conductive filler; (D) a silane coupling agent; and (E) catalyst; Here, component (D) is a compound represented by the following general formulas (i) to (iii): [ka] [In each formula, R 1は R independently represents hydrogen or a vinyl group. 2は each independently represents an alkyl group having 1 to 4 carbon atoms. and mixtures thereof, and component (D) is present in an amount of less than 1 weight percent, based on the total weight of the composition.

[0025] (A) Alkenyl group-containing organopolysiloxane According to the present invention, the thermally conductive silicone adhesive composition comprises (A) an alkenyl group-containing organopolysiloxane.

[0026] As used herein, "alkenyl" refers to a straight or branched chain hydrocarbon group having 2 to 40 carbon atoms and one or more carbon-carbon double bonds (e.g., 1, 2, 3, or 4 double bonds) ("C 2-40 In some embodiments, an alkenyl group has 2 to 30 carbon atoms ("C 2-30 In some embodiments, the alkenyl group has 2 to 20 carbon atoms ("C 2-20 In some embodiments, the alkenyl group has 2 to 10 carbon atoms ("C 2-10 In some embodiments, the alkenyl group has 2 to 9 carbon atoms ("C 2-9 In some embodiments, the alkenyl group has 2 to 8 carbon atoms ("C 2-8 In some embodiments, the alkenyl group has 2 to 7 carbon atoms ("C 2-7 In some embodiments, the alkenyl group has 2 to 6 carbon atoms ("C 2-6 In some embodiments, the alkenyl group has 2 to 5 carbon atoms ("C 2-5 In some embodiments, the alkenyl group has 2 to 4 carbon atoms ("C 2-4 In some embodiments, the alkenyl group has 2 to 3 carbon atoms ("C 2-3 In some embodiments, an alkenyl group has two carbon atoms ("C2 alkenyl"). The one or more carbon-carbon double bonds can be internal (such as 2-butenyl) or terminal (such as 1-butenyl). C 2-4 Examples of alkenyl groups include ethenyl (C2), 1-propenyl (C3), 2-propenyl (C3), 1-butenyl (C4), 2-butenyl (C4), butadienyl (C4), and the like. 2-6 Examples of alkenyl groups include the aforementioned C 2-4Examples of alkenyl groups include pentenyl (C5), pentadienyl (C5), hexenyl (C6), and the like. Further examples of alkenyl include heptenyl (C7), octenyl (C8), octatrienyl (C8), and the like. Unless otherwise specified, each instance of an alkenyl group is independently unsubstituted (an "unsubstituted alkenyl") or substituted with one or more substituents (a "substituted alkenyl"). In certain embodiments, an alkenyl group is an unsubstituted C 2-30 In certain embodiments, the alkenyl group is a substituted C 2-30 It is alkenyl.

[0027] In some embodiments, the amount of alkenyl groups is within the range of 0.01 to 10% by weight, preferably 0.1 to 5% by weight, based on the total weight of the organopolysiloxane. These alkenyl groups may be bonded to terminal silicon atoms in the molecular chain, to non-terminal silicon atoms in the molecular chain, or to both of these silicon atoms. However, from the viewpoint of improving the curing rate of the composition and imparting desirable physical properties to the cured product, it is preferred that the organopolysiloxane contains alkenyl groups bonded to at least terminal silicon atoms in the molecular chain, and preferably to silicon atoms at both molecular chain ends.

[0028] In some embodiments, the viscosity of component (A) at 25°C is in the range of 10 to 1000 mPa·s, preferably 10 to 500 mPa·s. A viscosity at 25°C within this range can improve the physical properties of the cured silicone adhesive. The viscosity was measured using a TA rheometer parallel plate with a 25 mm spindle at 60 rpm at 25°C.

[0029] The molecular structure of component (A) is not particularly limited, and examples include, but are not limited to, a linear structure, a cyclic structure, a branched-chain structure, a partially branched linear structure, and a three-dimensional network structure. However, essentially linear diorganopolysiloxanes in which the main chain is formed from repeating diorganosiloxane units and both ends of the molecular chain are capped with triorganosiloxy groups are preferred. Furthermore, component (A) may be a single polymer having such a molecular structure, a copolymer having such a molecular structure, or a mixture of different polymers having such a molecular structure.

[0030] Specific examples of component (A) include compounds represented by the following general formulas (iv) to (viii). [ka] [ka] [ka] [ka] [ka]

[0031] In the above formulas (iv) to (viii), each R independently represents a substituted or unsubstituted monovalent hydrocarbon group bonded to a silicon atom, preferably a methyl group or a phenyl group, excluding alkenyl groups as described above. In formulas (iv) to (viii), n is an integer from 0 to 5,000, m is an integer from 5 to 5,000, and the sum of n and m is in the range of 5 to 10,000. In some embodiments, n is in the range of from 0, 10, 50, 100, 200, or 500 to 1,000, 2,000, or 5,000, or any range defined between any two of the aforementioned values; and m is in the range of from 5, 10, 50, or 200 to 500, 1,000, 2,000, or 5,000, or any range defined between any two of the aforementioned values. Furthermore, the sum of n and m can range from 5, 10, 30, 50, 100, 200, 500, to 1000, 2000, 5000, 10000, or any range defined between any two of the aforementioned values, e.g., 10-10000, 1000-5000.

[0032] In some embodiments, the unsubstituted or substituted monovalent hydrocarbon groups R in the above formulas (iv) to (viii) are each independently a straight-chain alkyl group, preferably a straight-chain alkyl group selected from methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-pentadecyl, n-hexadecyl, n-heptadecyl, n-octadecyl, n-nonadecyl, and n-eicosyl groups; preferably an isopropyl group, a t-butyl group, an isobutyl group, a 2-methylundecyl group, and branched alkyl groups selected from 1-hexylheptyl and 1-hexylheptyl; cyclic alkyl groups, preferably selected from cyclopentyl, cyclohexyl, and cyclododecyl; aryl groups, preferably selected from phenyl, tolyl, and xylyl; aralkyl groups, preferably selected from benzyl, phenethyl, and 2-(2,4,6-trimethylphenyl)propyl; and halogenated alkyl groups, preferably selected from 3,3,3-trifluoropropyl and 3-chloropropyl; preferably selected from straight-chain alkyl groups and aryl groups; and more preferably selected from methyl, ethyl, and phenyl groups.

[0033] In a preferred embodiment, component (A) is selected from the group consisting of vinyl-terminated polydimethylsiloxane, vinyl-terminated diphenylsiloxane-dimethylsiloxane copolymer, vinyl-terminated polyphenylsiloxane, vinylbenzyl-terminated vinylphenylsiloxane-phenylmethylsiloxane copolymer, vinyl-terminated trifluoropropylmethylsiloxane-dimethylsiloxane copolymer, vinyl-terminated diethylsiloxane-dimethylsiloxane copolymer, vinylmethylsiloxane-dimethylsiloxane copolymer, trimethylsilanyl-terminated vinylmethylsiloxane-dimethylsiloxane copolymer, silanol-terminated vinyl The polymer may be selected from methylsiloxane-dimethylsiloxane copolymer, vinylmethylsiloxane homopolymer, vinylmethylsiloxane copolymer, vinyl-terminated poly(methylsiloxane) copolymer, vinyl-terminated poly(methylsiloxane) copolymer, polyvinyl-terminated poly(methylsiloxane) copolymer, poly(vinyl-terminated poly(methylsiloxane) copolymer, poly(vinyl-terminated poly(methylsiloxane) and poly(vinylsiloxane) copolymer, monovinyl-terminated polydimethylsiloxane, vinylmethylsiloxane terpolymer, vinylmethoxysilane homopolymer, or combinations thereof.

[0034] There are no particular restrictions on the molecular weight of component (A), but it is preferably in the range of 3,000 to 20,000 g / mol.

[0035] The component (A) may be used alone or in combination of two or more different compounds.

[0036] The alkenyl-containing organopolysiloxane used as component (A) can be produced by a conventional method. In a typical production method, the alkenyl-containing organopolysiloxane is produced by carrying out an equilibrium reaction between an organocyclooligosiloxane and a hexaorganodisiloxane in the presence of an alkali or acid catalyst.

[0037] Commercially available products of component (A) include vinyl-terminated polydimethylsiloxanes Vi 393, Vi 70E, and Vi 100E manufactured by Zhejiang Runhe Chemical New Materials Co., Ltd.

[0038] According to the present invention, component (A) is present in an amount of 0.01% to 5% by weight, preferably 0.05% to 4% by weight, based on the total weight of the composition.

[0039] (B) Organohydrogenpolysiloxane According to the present invention, the thermally conductive silicone adhesive composition also contains an organohydrogenpolysiloxane (B) having an average of at least two hydrogen atoms directly bonded to silicon atoms per molecule, which acts as a crosslinker for component (A) to form a silicone polymer matrix.

[0040] In one embodiment, the organohydrogenpolysiloxane has two or more -Si-H groups per molecule. The -Si-H groups in component (B) and the alkenyl groups in component (A) are added via a hydrosilylation reaction promoted by the catalyst (E), described below, to form a three-dimensional network structure with a crosslinked structure.

[0041] Component (B) may have an average of at least two, and preferably three or more, -Si-H groups per molecule, and these -Si-H groups may be located at terminal, non-terminal, or both positions on the molecular chain.

[0042] In one embodiment, the organohydrogenpolysiloxane is linear or branched, and in a preferred embodiment, the organohydrogenpolysiloxane may be represented by the general formula (ix): [ka]

[0043] In the formula (ix), R' groups each independently represent a hydrogen atom or an unsubstituted or substituted monovalent hydrocarbon group excluding aliphatic unsaturated bonds, and at least two R' groups are hydrogen atoms. Index e represents an integer of 1 or greater.

[0044] Suitable examples of unsubstituted or substituted monovalent hydrocarbon groups in general formula (ix) are each independently selected from linear alkyl groups, preferably methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-pentadecyl, n-hexadecyl, n-heptadecyl, n-octadecyl, n-nonadecyl, and n-eicosyl groups; branched alkyl groups, preferably isopropyl, t-butyl, isobutyl, 2-methylundecyl, and 1-hexylheptyl; cyclic alkyl groups, preferably selected from cyclopentyl, cyclohexyl, and cyclododecyl groups; aryl groups, preferably selected from phenyl, tolyl, and xylyl groups; aralkyl groups, preferably selected from benzyl, phenethyl, and 2-(2,4,6-trimethylphenyl)propyl groups; and halogenated alkyl groups, preferably selected from 3,3,3-trifluoropropyl and 3-chloropropyl groups, preferably selected from straight-chain alkyl groups and aryl groups; and more preferably selected from methyl, ethyl, and phenyl groups.

[0045] The content of functional groups of -Si-H groups in component (B) is preferably in the range of 0.1 to 10.0 mmol / g, more preferably 0.1 to 5.0 mmol / g.

[0046] In a preferred embodiment, the number of moles of -Si-H groups contained in component (B) is preferably 0.1 to 5.0 times the number of moles of alkenyl groups derived from component (A).

[0047] Specific examples of component (B) include 1,1,3,3-tetramethyldisiloxane, dimethylhydrosiloxane, methylhydrogencyclopolysiloxane, cyclic copolymer of methylhydrogensiloxane and dimethylsiloxane, methylhydrogenpolysiloxane terminated at both ends with trimethylsiloxy groups, copolymer of dimethylsiloxane and methylhydrogensiloxane terminated at both ends with trimethylsiloxy groups, dimethylpolysiloxane terminated at both ends with dimethylhydrogensiloxy groups, dimethylpolysiloxane terminated at both ends with dimethylhydrogensiloxy groups, Examples of the siloxane include, but are not limited to, a copolymer of dimethylsiloxane and methylhydrogensiloxane terminated at both ends with trimethylsiloxy groups, a copolymer of methylhydrogensiloxane and diphenylsiloxane terminated at both ends with trimethylsiloxy groups, a copolymer of methylhydrogensiloxane, diphenylsiloxane, and dimethylsiloxane terminated at both ends with trimethylsiloxy groups, and a copolymer of methylhydrogensiloxane, dimethylsiloxane, and diphenylsiloxane terminated at both ends with dimethylhydrogensiloxy groups.

[0048] Component (B) can be produced using conventional methods. A typical production method involves equilibrating octamethylcyclotetrasiloxane and / or tetramethylcyclodisiloxane with a compound that forms a terminal group, such as hexamethyldisiloxane, or a compound containing 1,1'-dihydro-2,2',3,3'-tetramethyldisiloxane units, in the presence of a catalyst such as sulfuric acid, trifluoromethanesulfonic acid, or methanesulfonic acid at a temperature of -10°C to 40°C. Commercially available products are also available. Examples of commercially available products of component (B) include RH-H86 and H3 dimethylhydrosiloxane, DH04 hydrogen-terminated polydimethylsiloxane, and H57 polydimethylmethylhydrosiloxane, all manufactured by Zhejiang Runhe Chemical New Materials Co., Ltd.

[0049] According to the present invention, component (B) is present in an amount of 0.01% to 5% by weight, preferably 0.05% to 3% by weight, based on the total weight of the composition.

[0050] (C) Thermally conductive filler According to the present invention, the thermally conductive silicone adhesive composition contains (C) a thermally conductive filler.

[0051] In some embodiments, component (C) can be selected from alumina particles, aluminum nitride particles, fumed silica particles, precipitated silica particles, fumed titanium oxide particles, and combinations thereof, preferably alumina particles, aluminum nitride particles, and combinations thereof.

[0052] In one embodiment, D of component (C) 50 The particle size is less than 200 μm, preferably less than 100 μm.

[0053] Here, "D 50 The term "particle size" refers to the median diameter in a volume-based particle size distribution curve measured with a laser diffraction particle size analyzer.

[0054] In a preferred embodiment, component (C) is D 50 At least one alumina particle having a particle size of 0.01 μm to 2 μm, preferably 0.1 μm to 1 μm, and D 50 and at least one aluminum nitride particle having a particle size of 1 μm to 200 μm, preferably 1 μm to 100 μm.

[0055] In a preferred embodiment, component (C) is D 50 At least one alumina particle having a particle size of 0.01 μm to 2 μm, preferably 0.1 μm to 1 μm, and D 50 At least one aluminum nitride particle having a particle size of 50 μm to 100 μm, preferably 70 μm to 100 μm, and D 50 and at least one aluminum nitride particle having a particle size of 1 μm to 50 μm, preferably 1 μm to 30 μm.

[0056] The shape of component (C) used in the present invention is not particularly limited. The shape may be spherical, rod-like, needle-like, disc-like, or amorphous, with spherical being preferred. In this specification, "spherical" refers to a shape in which the entire surface is formed as a convex, smooth surface.

[0057] Component (C) may be surface-treated or untreated. In the present invention, it is preferable to use surface-treated particles as component (C) to enhance compatibility with component (C) in the silicone polymer matrix. The particles can be surface-treated with a surface treatment agent such as a silane compound, an organotitanium compound, an organoaluminum compound, or a phosphate compound, preferably a silane compound.

[0058] In a preferred embodiment, the amount of the surface treatment agent attached to the thermal particles is, for example, 0.01% to 2% by weight, preferably 0.02% to 1.5% by weight, and more preferably 0.03% to 1% by weight, based on the weight of the thermal particles. If the content of the surface treatment agent is within the above range, the compatibility of the thermal particles with other thermal particles is improved.

[0059] The silane compound used for the surface treatment is not particularly limited, but examples thereof include alkoxysilanes and chlorosilanes, with alkoxysilanes being preferred. Thermal particles surface-treated with a silane compound are more likely to conform to the silicone polymer matrix, making it easier to increase the amount of thermal particles incorporated into the thermally conductive composition.

[0060] Examples of the alkoxysilane include alkoxysilanes having a reactive group, alkoxysilanes not having a reactive group, etc. The reactive group of the alkoxysilane having a reactive group is selected from, for example, an epoxy group, a (meth)acryloyl group, an amino group, a vinyl group, a ureido group, a mercapto group, and an isocyanate group.

[0061] Examples of alkoxysilanes having an epoxy group include 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 3-glycidoxypropyltriethoxysilane. Examples of alkoxysilanes having a (meth)acryloyl group include 3-(meth)acryloyloxypropylmethyldimethoxysilane, 3-(meth)acryloyloxypropyltrimethoxysilane, 3-(meth)acryloyloxypropylmethyldiethoxysilane, and 3-(meth)acryloyloxypropyltriethoxysilane. Examples of silane compounds having an amino group include alkoxysilanes such as N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, and N-phenyl-3-aminopropyltrimethoxysilane. Examples of silane compounds having a vinyl group include vinyltrimethoxysilane and vinyltriethoxysilane. Examples of alkoxysilanes having a mercapto group include 3-mercaptopropyltrimethoxysilane and 3-mercaptopropylmethyldimethoxysilane. Examples of alkoxysilanes having a ureido group include 3-ureidopropyltrimethoxysilane. Examples of alkoxysilanes having an isocyanate group include 3-isocyanatopropyltriethoxysilane. Examples of alkoxysilanes having no reactive group include trialkoxysilanes such as aryltrialkoxysilanes and alkyltrialkoxysilanes, and dialkoxysilanes such as dialkyldialkoxysilanes and diaryldialkoxysilanes. Of these, trialkoxysilanes such as alkyltrialkoxysilanes are preferred.Examples of alkyltrialkoxysilanes include alkyltrialkoxysilanes having an alkyl group with a carbon atom number D of about 1 to 10, such as methyltrimethoxysilane, methyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, n-hexyltrimethoxysilane, n-hexyltriethoxysilane, n-octyltriethoxysilane, and n-decyltrimethoxysilane. Examples of aryltrimethoxysilanes include aryltrimethoxysilanes having an aryl group with a carbon atom number of about 6 to 10, such as phenyltrimethoxysilane, benzyltrimethoxysilane, and tolyltrimethoxysilane. Examples of dialkoxysilanes include dimethyldimethoxysilane and dimethyldiethoxysilane. A preferred embodiment of the silane compound is a polymeric silane compound that is a reaction product of an alkoxy product having a reactive group and a polyorganosiloxane having a functional group capable of reacting with the reactive group.

[0062] Suitable polymeric silane compounds can be obtained, for example, by mixing an alkoxysilane having a reactive group with a polyorganosiloxane and heating the mixture in the presence of a catalyst such as a platinum catalyst, a palladium catalyst, or a rhodium catalyst. The alkoxysilane having a reactive group can be any of those listed above, but trialkoxysilanes are preferred. As the alkoxysilane having a reactive group, silane compounds having a (meth)acryloyl group or a vinyl group are preferred, with trialkoxysilanes having a (meth)acryloyl group being more preferred. Silane compounds having a (meth)acryloyl group or a vinyl group readily react with organopolysiloxanes having hydrosilyl groups (—SiH), as described below, allowing polymeric silane compounds to be obtained by a simple method. The polyorganosiloxanes having functional groups used in the polymeric silane compounds may have one functional group or two or more functional groups. When the polyorganosiloxane has two or more functional groups, two or more molecules of alkoxysilane having a reactive group may be bonded to one molecule of the polyorganosiloxane. As the polyorganosiloxane having a functional group, an organopolysiloxane having a hydrosilyl group (-SiH) is preferred. Examples of organopolysiloxanes having a hydrosilyl group (-SiH) include methylhydrosiloxane-dimethylsiloxane copolymers and methylhydrosiloxane-phenylmethylsiloxane copolymers. These may or may not contain hydrosilyl groups at their terminals. The weight-average molecular weight of the polyorganosiloxane having a functional group is preferably 800 to 5,000, more preferably 1,500 to 4,000. Here, the weight-average molecular weight is a polystyrene-equivalent value measured by GPC.

[0063] The surface treatment method using a silane compound is not particularly limited, and well-known methods, such as wet treatment, dry treatment, and pretreatment, can be used. Among these, wet treatment is preferred in the present invention. In the wet treatment, for example, thermal particles are added to a solution in which a silane compound is dispersed or dissolved, and the mixture is mixed, followed by heat treatment to bond or adhere the silane compound to the surface of the thermal particles. The dry treatment is a surface treatment method that does not use a solution. Specifically, the dry treatment is a method in which thermal particles and a silane compound are mixed, stirred in a mixer, or the like, and then heat treatment is performed to bond or adhere the silane compound to the surface of the thermal particles.

[0064] Suitable commercially available products of component (C) include AN5, AN20, and AN30 alumina particles manufactured by Suzhou Guinet New Material Technology Co., Ltd., AA04 manufactured by Sumitomo Chemical Co., Ltd., NSM-1 and BAK-2 manufactured by Vestry Performance Materials Co., Ltd., DAM-03 manufactured by Denka Co., Ltd., AN80, AND-A-01 aluminum nitride particles manufactured by Suzhou Guinet New Material Technology Co., Ltd., and the like.

[0065] In particularly preferred embodiments, component (C) is present in an amount of 0.01% to 99% by weight, preferably 50% to 99% by weight, based on the total weight of the composition.

[0066] (D) silane coupling agent According to the present invention, the thermally conductive silicone adhesive composition comprises (D) a silane coupling agent selected from the following general formulas (i) to (iii) and mixtures thereof: [ka]

[0067] In each formula, R1 independently represents hydrogen or a vinyl group, R2 independently represents an alkyl group having 1 to 4 carbon atoms; and component (D) is present in an amount of less than 1 weight percent, based on the total weight of the composition.

[0068] Suitable silane coupling agents that can be used in the present invention include, but are not limited to, trimethoxysilane, dimethoxy(methyl)silane, dimethoxy(ethyl)silane, dimethoxy(propyl)silane, dimethoxy(butyl)silane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyldimethoxy(methyl)silane, and the like.

[0069] Commercially available silane coupling agents include D2100 and T1035 from TCI, and Silquest A 2171 and Silquest A 171 from Momentive.

[0070] In one embodiment, component (D) is present in an amount of from 0.01 to less than 1 wt %, preferably from 0.05 to less than 1 wt %, and more preferably from 0.05 to less than 0.5 wt %, based on the total weight of the composition, to improve the thermal conductivity of the cured product obtained from the composition.

[0071] (E) catalyst In accordance with the present invention, the thermally conductive silicone adhesive composition includes (E) a catalyst that accelerates the curing process.

[0072] Component (E) is a catalyst that promotes the addition reaction between the alkenyl group derived from component (A) and the —Si—H group derived from component (B), and any catalyst known for use in hydrosilylation reactions can be used.

[0073] Specifically, platinum group metals such as platinum (including platinum black), rhodium, and palladium; platinum chloride, chloroplatinic acid, and chloroplatinic acid salts, such as HPtCl·nH0, HPtCl·nH0, NaHPtCl·nH0, KaHPtCl·nH0, NaPtCl·H0, KPtCl·nH0, PtCl·nH0, PtCl, and NaHPtCl·nH0 (wherein n is an integer of 0 to 6, preferably Examples of suitable catalysts include alcohol-modified chloroplatinic acid; complexes of chloroplatinic acid with olefins; platinum black, platinum group metals such as palladium supported on supports such as alumina, silica, and carbon; rhodium-olefin complexes, and chlorotris(triphenylphosphine)rhodium (Wilkinson's catalyst); and complexes of platinum chloride, chloroplatinic acid, or chloroplatinate with vinyl group-containing siloxanes, particularly vinyl group-containing cyclic siloxanes.

[0074] Examples of suitable commercially available catalysts include Evonik's CATALYST 512 and Avantor's CAT-50.

[0075] According to the present invention, component (E) is present in an amount of 0.001% to 0.1% by weight, preferably 0.001% to 0.05% by weight, based on the total weight of the composition.

[0076] (F) additives In some embodiments, the thermally conductive silicone adhesive composition may further optionally contain additives selected from inhibitors, pigments, dyes, fluorescent dyes, heat resistance additives, flame retardants, plasticizers, adhesion promoters, and combinations thereof, provided that the inclusion of these additives does not detract from the objectives of the present invention.

[0077] Suitable examples of inhibitors (blockers) for use in the present invention include, but are not limited to, acetylene-based compounds such as 2-methyl-3-butyn-2-ol, 2-phenyl-3-butyn-2-ol, and 1-ethynyl-1-cyclohexanol, hydrazine-based compounds, phosphine-based compounds, and mercaptan-based compounds. The inhibitor can adjust the curing speed of the composition, thereby improving the flowability and workability.

[0078] Examples of suitable commercially available inhibitors include Inhibitor MVC from Evonik and 3,5-dimethyl-1-hexyn-3-ol from Sigma-Aldrich Company.

[0079] Suitable commercially available pigments include red pigments manufactured by Lanxess.

[0080] When the composition of the present invention contains an additive, the amount of the additive is not particularly limited, but is preferably in the range of 0.0001 to 1.0% by weight based on the total weight of the composition.

[0081] In a particularly preferred embodiment, the thermally conductive silicone adhesive composition comprises, based on the total weight of the composition: (A) 0.01% by weight to 5% by weight, preferably 0.05% by weight to 4% by weight, of an alkenyl group-containing organopolysiloxane; (B) 0.01% by weight to 5% by weight, preferably 0.05% by weight to 3% by weight, of an organohydrogenpolysiloxane having an average of at least two hydrogen atoms directly bonded to silicon atoms per molecule; (C) 0.01% by weight to 99% by weight, more preferably 50% by weight to 99% by weight, of a thermally conductive filler; (D) 0.01% by weight or more and less than 1% by weight, preferably 0.05% by weight or more and less than 1% by weight, more preferably 0.05% by weight or more and less than 0.5% by weight of a silane coupling agent; (E) 0.001% to 0.1% by weight, preferably 0.001% to 0.05% by weight, of a catalyst, and (F) additives 0-1.0 wt%; wherein component (D) is selected from the following general formulae (i) to (iii) and mixtures thereof: [ka]

[0082] In each formula, R1 independently represents hydrogen or a vinyl group, and R2 independently represents an alkyl group having 1 to 4 carbon atoms.

[0083] A further aspect of the present invention relates to a method for preparing a thermally conductive silicone adhesive composition by mixing the components simultaneously at room temperature, for example for at least 1 hour, preferably at least 2 hours.

[0084] The thermally conductive silicone adhesive composition of the present invention, when cured with a thermally conductive filler loading of greater than 80%, has good fluidity, for example, a flow rate of greater than 15 g / min, preferably greater than 18 g / min, defined as the weight of 30 cc of adhesive composition with a nozzle having a diameter of 2.54 ± 5 ​​mm. Such a flow rate, particularly a flow rate greater than 15 g / min, prevents the nozzle of a conventional adhesive dispenser from becoming clogged with the adhesive composition after mixing.

[0085] In a preferred embodiment, the thermally conductive silicone adhesive composition can be cured at room temperature within 7 days. Curing can be accelerated by heating, for example, at 60 to 200°C for 30 minutes to 2 hours.

[0086] In the present invention, the thermally conductive silicone adhesive composition can be applied to the desired substrate by any convenient technique. It can be applied cold, or warm if necessary. It can be applied by extrusion or pasting onto the substrate, or by mechanical application methods such as a caulking gun. Typically, the thermally conductive silicone adhesive composition of the present invention is applied to one side of a pair of substrates, and the substrates are then brought into contact with each other to bond them. After application, the thermally conductive silicone adhesive composition of the present invention cures at room temperature, and then, if necessary, is subsequently cured at an elevated temperature.

[0087] In another aspect of the invention, there is provided an article comprising a first substrate, a cured adhesive, and a second substrate adhered to the first substrate via the cured adhesive comprising a cured product derived from the curable adhesive composition of any one of the preceding items.

[0088] The first substrate and / or the second substrate can be composed of a single material and a single layer, or multiple layers of the same or different materials. The layers can be continuous or discontinuous.

[0089] The substrate of the articles described herein may have a variety of properties, including rigidity (e.g., a rigid substrate (i.e., the substrate cannot be bent using both hands or will break if an attempt is made to bend it using both hands), flexibility (e.g., a flexible substrate (i.e., the substrate can be bent using the strength of both hands), porous, conductive, non-conductive, and combinations thereof.

[0090] The substrate can take a variety of forms, including, for example, fibers, threads, yarns, woven fabrics, nonwoven fabrics, films (e.g., polymeric films, metallized polymeric films, continuous films, discontinuous films, and combinations thereof), foils (e.g., metal foils), sheets (e.g., metal sheets, polymeric sheets, continuous sheets, discontinuous sheets, and combinations thereof), and combinations thereof.

[0091] Useful substrate materials for use in the present invention include, for example, polymers (e.g., polycarbonate, ABS resin (acrylonitrile-butadiene-styrene resin), liquid crystal polymers, polyolefins (e.g., polypropylene, polyethylene, low-density polyethylene, linear low-density polyethylene, high-density polyethylene, polypropylene, oriented polypropylene, copolymers of polyolefins with other comonomers), polyether terephthalate, ethylene vinyl acetate, ethylene methacrylic acid ionomer, ethylene vinyl alcohol, polyesters (e.g., polyethylene terephthalate), polycarbonate, polyamides (e.g., nylon 6 and nylon 6,6), polyvinyl chloride, polyvinylidene chloride, cellulose, and the like. Examples of suitable composite materials include glass, cellulose, polystyrene, and epoxy), polymer composites (e.g., composites of polymers and metals, cellulose, glass, polymers, and combinations thereof), metals (aluminum, copper, zinc, lead, gold, silver, platinum, magnesium, and metal alloys (e.g., steel (e.g., stainless steel), tin, brass, and alloys of magnesium and aluminum), carbon fiber composites, other fiber-based composites, graphene, fillers, glass (e.g., alkali aluminosilicate glass and borosilicate glass), quartz, boron nitride, gallium nitride, sapphire, silicon, carbide, ceramics, and combinations thereof, preferably liquid crystal polymers, glass, and combinations thereof.

[0092] The cured product of the thermally conductive silicone adhesive composition of the present invention has a thermal conductivity of greater than 10 W / (m·K), preferably greater than 11 W / (m·K), as measured in accordance with ASTM-D5470.

[0093] A further aspect related to the present invention relates to the use of the thermally conductive silicone adhesive composition according to the present invention and the cured product of the thermally conductive silicone adhesive composition in the manufacture of electronic devices, in particular telecommunications and data communication devices such as 5G stations.

[0094] Exemplary electronic devices include computers and computer equipment, such as telecommunications and data communications devices, such as 5G stations; printers, fax machines, scanners, keyboards, and the like; medical sensors; automotive sensors, and the like; wearable electronic devices (e.g., watches and eyeglasses) and their integrated circuit elements, handheld electronic devices (e.g., phones (e.g., cell phones and smartphones) and their integrated circuit elements, cameras, tablets, e-readers, monitors (e.g., monitors used in hospitals and by medical professionals, athletes, and individuals), watches, calculators, mice, touchpads, joysticks, and the like), computers (e.g., desktop and laptop computers) and their integrated circuit elements, computer monitors, televisions, media players, household appliances (e.g., refrigerators, washers, dryers, ovens, microwaves), light bulbs (e.g., incandescent, light emitting diode, fluorescent), and articles containing visible, transparent or transparent components, glass housing structures, protective transparent covers for displays or other optical components.

[0095] According to the present invention, the use of the embodiments described above as being suitable or more suitable for the thermally conductive silicone adhesive composition of the present invention is preferred, and it is preferred that two or more of the above embodiments or corresponding features described for the thermally conductive silicone adhesive composition are combined with one another. [Example]

[0096] Example The following examples are intended to help those skilled in the art better understand and practice the present invention. The scope of the present invention is not limited by the examples, but is defined by the appended claims. Unless otherwise specified, all parts and percentages are by weight.

[0097] raw materials: Component (A) Component a: RH-Vi100E is a vinyl-terminated polydimethylsiloxane with a viscosity of less than 100 mPa·s, manufactured by Zhejiang Runhe Chemical New Materials Co., Ltd.

[0098] Ingredient (B) Component b: RH-H86 is a dimethylhydrosiloxane manufactured by Zhejiang Runhe Chemical New Materials Co., Ltd.

[0099] Ingredients (C) Component c-1: AN80 is aluminum nitride powder (D 50 =70~100μm). Component c-2: AND-A-01 is aluminum nitride powder (D 50 =1 to 30 μm). Component c-3: AA05 is alumina powder (D 50 =0.5 μm).

[0100] Ingredients (D) Component d-1: D2100 is dimethoxy(methyl)silane manufactured by TCI. Component d-2: T1035 is a trimethoxysilane manufactured by TCI. Component d-3: Silquest A 2171 is vinyldimethoxy(methyl)silane manufactured by Momentive. Component d-4: Silquest A 171 is a vinyltrimethoxysilane manufactured by Momentive. Component d-5:9116 is methyltrimethoxysilane manufactured by Evonik.

[0101] Ingredient (E) Component e: CATALYST 512 is a divinyltetramethyldisiloxane complex containing 2% by weight of platinum manufactured by Evonik.

[0102] Ingredient (F) Component f is a red pigment manufactured by Lanxess.

[0103] Test Method: Flow rate: The flow rates of the thermally conductive silicone adhesive composition of the present invention and the comparative sample were measured using a dispenser machine (Nordson Ultimus TM The test was performed under the conditions of 1.0-1.0 mm. The dispenser machine contained a 30 cc plastic tube with a nozzle having a diameter of 2.54 ± 5 ​​mm, and the tube was connected to a pressure unit. During the test, the sample was dispensed onto a balance tray at a pressure of 90 psi within one minute. The weight of the sample dispensed in one minute was measured and recorded as the flow rate value in Table 1. A higher flow rate value indicates a more fluid and easier handling of the thermally conductive silicone adhesive composition. A flow rate of more than 15 g / min is acceptable.

[0104] Thermal Conductivity: The thermally conductive silicone adhesive compositions of the present invention and comparative examples were cured at 125°C for 1 hour. The thermal conductivity of the cured samples of the present invention was tested at 80°C and 40 psi pressure using a Longwin LW9389 adhesive in accordance with ASTM-D5470. A thermal conductivity greater than 10 W / (m·K) is acceptable.

[0105] Examples 1 to 5 (Ex.1 to Ex.5) and Comparative Examples 1 to 2 (CEx.1 to CEx.2) The inventive and comparative thermally conductive silicone adhesive compositions were prepared by mixing the components in the weight percents listed in Table 1 in a 2-liter planetary mixer (manufactured by Rose (Wuxi) Equipment Co., Ltd.) at room temperature for 2 hours, then cooling to room temperature. The properties were tested using the methods described above. The evaluation results are shown in Table 1 below.

[0106] [Table 1]

[0107] As can be seen from Table 1, the thermally conductive silicone adhesives of the present invention (Examples 1 to 5) exhibited good fluidity and high thermal conductivity even after curing. However, when the components of the present invention were not used, as in Comparative Examples 1 and 2 (CEx.1 and CEx.2), the fluidity of the thermally conductive silicones of the present invention was insufficient compared to the adhesive compositions, which tended to clog the nozzles of conventional adhesive dispensers and did not provide sufficient thermal conductivity for heat dissipation in electronic devices.

[0108] While several preferred embodiments have been described, many modifications and variations are possible in light of the above teachings. It is therefore understood that the invention can be practiced otherwise than as specifically described without departing from the scope of the appended claims.

Claims

1. (A) an alkenyl group-containing organopolysiloxane; (B) an organohydrogenpolysiloxane having, on average, at least two hydrogen atoms directly bonded to silicon atoms per molecule; (C) a thermally conductive filler; (D) a silane coupling agent; and (E) a catalyst; A thermally conductive silicone adhesive composition comprising: Component (D) is a compound represented by the following general formulas (i) to (iii): 【Chemistry 1】 [In each formula, R １ each independently represents hydrogen or a vinyl group; R ２ each independently represents an alkyl group having 1 to 4 carbon atoms. and mixtures thereof; and Component (D) is present in an amount of less than 1 wt. %, based on the total weight of the composition; A thermally conductive silicone adhesive composition.

2. Component (A) is a compound represented by the following general formulas (iv) to (viii): 【Chemistry 2】 (iv) 【Transformation 3】 (v) 【Chemistry 4】 (vi) 【Transformation 5】 (vii) 【Transformation 6】 (viii) [wherein, in each formula, R represents a substituted or unsubstituted monovalent hydrocarbon group excluding an alkenyl group; in formulas (iv) to (viii), n is an integer of 0 to 5,000, m is an integer of 5 to 5,000, and the sum of n and m is in the range of 5 to 10,000] 10. The thermally conductive silicone adhesive composition of claim 1, wherein the silicone is selected from any one of the following:

3. 3. The thermally conductive silicone adhesive composition according to claim 1, wherein component (A) has a viscosity at 25°C of 10 to 1000 mPa·s, preferably 10 to 100 mPa·s.

4. Component (B) is a compound represented by general formula (ix): 【Transformation 7】 (ix) [wherein each R′ independently represents a hydrogen atom or an unsubstituted or substituted monovalent hydrocarbon group excluding an aliphatic unsaturated bond, at least two R′ groups are hydrogen atoms, and e represents an integer of 1 or greater] is expressed as The thermally conductive silicone adhesive composition according to any one of claims 1 to 2.

5. 3. The thermally conductive silicone adhesive composition according to claim 1, wherein component (C) is selected from alumina particles, aluminum nitride particles, fumed silica particles, precipitated silica particles, fumed titanium oxide particles, and combinations thereof, and is preferably alumina particles, aluminum nitride particles, or combinations thereof.

6. Component (C) D ５０ The thermally conductive silicone adhesive composition according to any one of claims 1 to 2, wherein the particle size is 200 µm or less, preferably 100 µm or less.

7. Component (C) is D ５０ At least one alumina particle having a particle size of 0.01 μm to 2 μm, preferably 0.1 μm to 1 μm; ５０ At least one aluminum nitride particle having a particle size of 1 μm to 200 μm, preferably 1 μm to 100 μm, and D ５０ and at least one aluminum nitride particle having a particle size of 1 μm to 50 μm, preferably 1 μm to 30 μm.

8. 3. The thermally conductive silicone adhesive composition according to claim 1, wherein component (A) is present in an amount of 0.01 to 5% by weight, preferably 0.05 to 4% by weight, based on the total weight of the composition.

9. 3. The thermally conductive silicone adhesive composition according to claim 1, wherein component (B) is present in an amount of 0.01 to 5% by weight, preferably 0.05 to 3% by weight, based on the total weight of the composition.

10. 3. The thermally conductive silicone adhesive composition of claim 1, wherein component (C) is present in an amount of 0.01% to 99% by weight, more preferably 50% to 99% by weight, based on the total weight of the composition.

11. 3. The thermally conductive silicone adhesive composition according to claim 1, wherein component (D) is present in an amount of at least 0.01 wt % but less than 1 wt %, preferably at least 0.05 wt % but less than 1 wt %, and even more preferably at least 0.05 wt % but less than 0.5 wt %, based on the total weight of the composition.

12. 3. The thermally conductive silicone adhesive composition according to claim 1, wherein component (E) is present in an amount of 0.001 wt % to 0.1 wt %, preferably 0.001 wt % to 0.05 wt %, based on the total weight of the composition.

13. A method for producing the thermally conductive silicone adhesive composition of any of claims 1 to 2, comprising the step of simultaneously mixing the components at room temperature.

14. A cured product of the thermally conductive silicone adhesive composition according to any one of claims 1 to 2.

15. 3. Use of the thermally conductive silicone adhesive composition according to claim 1 in the manufacture of electronic devices.

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