Polysiloxane composition

Abstract

The present invention relates to an organosilicon composition containing vinyl silicone oil, a thermally conductive filler, a silane compound, and a polysiloxane, which has low viscosity and thixotropy index under high loading conditions. This composition can be used in the technical field of thermally conductive materials.

Description

[Technical Field]

[0001] The present invention relates to the technical field of thermally conductive silicone compositions. [Background technology]

[0002] CN113840881A discloses a thermal interface material containing a long-chain alkyl hydroxyl-terminated silicone oil, a long-chain alkyl silicone oil, a long-chain alkyl vinyl-terminated silicone oil, and a thermally conductive filler. In particular, the composition may also contain one or more silane coupling agents. The long-chain alkyl hydroxyl-terminated silicone oil contains a long-chain alkyl branch. The general formula of the silane coupling agent is Y-(CH2) n -Si-X3, where Y is an organic functional group, X is a hydrolyzable group, and n is 10 to 20. CN113840881A discloses that a long-chain alkyl hydroxyl-terminated silicone oil and a long-chain alkyl silane coupling agent can be used in a thermal interface composition, where the number of carbon atoms in the long-chain alkyl group is generally 10 or more.

[0003] US6169142 discloses a composition comprising a vinyl silicone oil, a hydrogen-containing silicone oil, an alumina thermally conductive filler and a long-chain alkylalkoxysilane R 1 a Si(OR 2 ) (4-a) (In the formula, R 1 is a C6-20 hydrocarbon group). Table 2 specifically lists comparative experiments of Example 6 and CE2. The product of Example 6 (obtained with hexyltrimethoxysilane) has a lower viscosity at 100°C than CE2 (obtained with methyltriethoxysilane).

[0004] Currently, for potting devices with complex structures and narrow gaps, it is necessary to obtain compositions with lower flow properties at different shear rates. Better flow properties can reduce the flow deficiency of the potting adhesive and avoid air bubbles and shrinkage cavities. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Chinese Patent Application Publication No. 113840881 [Patent Document 2] U.S. Patent No. 6,169,142 Summary of the Invention

[0006] The present invention discloses compositions with a lower thixotropic index (lower thixotropy) at high loadings. The compositions have lower viscosity under both high and low shear conditions.

[0007] In the present invention, high shear means a shear rate of 10 (1 / sec) and low shear means a shear rate of 1 (1 / sec).

[0008] The present invention provides a composition comprising: Component (A) is an organopolysiloxane, preferably component (A-1) is an organopolysiloxane having two or more alkenyl groups per molecule; optionally, component (B), which is an organohydrogenpolysiloxane having two or more hydrogen atoms directly bonded to silicon atoms, and which is contained in an amount such that the number of moles of hydrogen atoms directly bonded to silicon atoms in component (B) is 0.1 to 5.0 times the number of moles of alkenyl groups derived from component (A-1); Component (C) is a thermally conductive filler, Component (C), in which the filling rate of the thermally conductive filler is 0.80 or more, preferably 0.84 or more, preferably 0.88 or more, preferably 0.89 or more, preferably 0.90 or more; Optionally, component (D) is a platinum group metal curing catalyst having a platinum group metal element content of 0.1 to 1,000 ppm by mass relative to component (A-1); Component (E-1), which is an alkoxysilane compound represented by the following formula (1): R 1 a R 2 b Si(OR 3 ) 4-a-b (1) [In general formula (1), Each R 1 each independently represents an alkyl group having 1 to 3 carbon atoms, preferably methyl or ethyl; Each R 2 each independently represents an unsubstituted or substituted hydrocarbon group having 1 to 3 carbon atoms, preferably methyl or ethyl; Each R 3 each independently represents an alkyl group having 1 to 6 carbon atoms, preferably an alkyl group having 1 to 3 carbon atoms, more preferably methyl or ethyl; a represents an integer of 1 to 3, and b represents an integer of 0 to 2, with the proviso that a+b represents an integer of 1 to 3; and Component (E-2) is a polysiloxane represented by the following general formula (2): R 1 3SiO-(R 1 2SiO) m -Si-R 1 (3-n) R 2 n (2) [In formula (2), Each R 1 each independently represents a hydrocarbon group having 1 to 6 carbon atoms, preferably an alkyl or alkenyl group having 1 to 3 carbon atoms, preferably methyl, ethyl, propyl, or vinyl, more preferably methyl; Each R 2 are independently -OH or -(CH2) p OH, p is an integer of 1 to 3, and R 2 is preferably hydroxyl, m≦50, more preferably m≦20, more preferably 6≦m≦18, for example 8, 10, 12, 14, 16; n is an integer, preferably 1 to 3, and more preferably 1.] DETAILED DESCRIPTION OF THE INVENTION

[0009] For the above composition, according to DIN 53019, the viscosity of component (E-2) at 25°C is 500 mPa s or less, preferably 300 mPa s or less, more preferably 100 mPa s or less, more preferably 50 mPa s or less, more preferably 10 to 40 mPa s.

[0010] According to NMR measurement, Mn of component (E-2) is 5000 g / mol or less, preferably 3000 g / mol or less, more preferably 2000 g / mol or less, more preferably 500 to 1500 g / mol.

[0011] According to NMR measurement, the hydroxyl value of component (E-2) is 10% by weight or less, preferably 5% by weight or less, more preferably 3% by weight or less, more preferably 1.0 to 2.8% by weight.

[0012] The thixotropy index (Ti) of the above composition at 25° C. is 1.70 or less, preferably 1.05 to 1.70, more preferably 1.20 to 1.70, and more preferably 1.30 to 1.55. If the thixotropy index exceeds 1.70, insufficient leveling is likely to occur, and unfilled gaps are likely to occur during potting of a slitted device, which is undesirable.

[0013] In the present invention, the thixotropy index (Ti) is the ratio of the viscosity η1 at a shear rate of 1 (1 / sec) to the viscosity η10 at a shear rate of 10 (1 / sec) at 25°C using a defined rheometer (Ti=η1 / η10).

[0014] In the present invention, the ratio of component (E-1) to component (C) is 0.02 to 1.00% by weight, preferably 0.05 to 0.50% by weight, more preferably 0.08 to 0.20% by weight, and even more preferably 0.08 to 0.15% by weight.

[0015] In the above composition, The weight ratio of the component (E-2) to the component (E-1) is 0.5 to 10, preferably 1 to 6, preferably 2 to 4, more preferably 2.5 to 3.5, for example, 2.3, 2.7, 2.9, 3.1, 3.3, or 3.7.

[0016] In the present invention, the ratio of component (E-2) to component (C) is 0.05 to 1.00% by weight, preferably 0.08 to 0.80% by weight, more preferably 0.08 to 0.60% by weight, and even more preferably 0.10 to 0.40% by weight.

[0017] In the present invention, the ratio of the total of components (E-1) and (E-2) to component (C) is 0.05 to 2.00% by weight, preferably 0.08 to 1.20% by weight, more preferably 0.10 to 1.00% by weight, more preferably 0.10 to 0.80% by weight, and more preferably 0.20 to 0.60% by weight.

[0018] In the present invention, the amount of the thixotropic agent is 1% by weight or less, preferably 0.1% by weight or less, calculated assuming the total amount of the composition to be 100% by weight.

[0019] Thixotropic agent: 100m 2 / g or more, preferably 150m 2 The silica particles are selected from montmorillonite, bentonite or metal oxide particles such as fumed silica and precipitated silica, having a BET specific surface area of ​​1 / g or more.

[0020] In the above composition, component (C) is treated with components (E-1) and (E-2).

[0021] In the above composition, component (C) is subjected to the thermal surface treatment of components (E-1) and (E-2).

[0022] Use of the above composition in the field of potting.

[0023] In electronics, potting is the process of filling a complete electronic assembly with a liquid or gelatinous composition to exclude gaseous phenomena such as corona discharge, for resistance to shock and vibration, and to exclude water, moisture, or corrosive agents.

[0024] A thermally conductive member comprising the above composition or a cured product thereof.

[0025] A heat dissipation structure including a heat conducting member.

[0026] A heat dissipation structure is obtained by providing a heat dissipation member on a heat dissipation component or a circuit board on which a heat dissipation component is mounted, via the composition or a cured product thereof.

[0027] The heat dissipation structure is an electric or electronic device.

[0028] In the above composition, the thermal conductivity at 25°C according to DIN 53019 is greater than 2.5 W / mk and, at a shear rate of 1 (1 / s), the initial viscosity of the composition after mixing is 100 Pa s or less, preferably 60 Pa s or less, more preferably 40 Pa s or less.

[0029] In the above composition, when the thermal conductivity at 25°C according to DIN 53019 is greater than 2.5 W / mk and the shear rate is 10 (1 / sec), the initial viscosity of the composition after mixing is 50 Pa s or less, preferably 30 Pa s or less, and more preferably 20 Pa s or less.

[0030] The composition has a thermal conductivity at 25°C according to DIN 53019 of less than 2.5 W / mk, and an initial viscosity after mixing of the composition after mixing at a shear rate of 1 (1 / s) of 60 Pa s or less, preferably 40 Pa s or less, more preferably 20 Pa s or less.

[0031] The composition has a thermal conductivity at 25°C according to DIN 53019 of less than 2.5 W / mk, and at a shear rate of 10 (1 / s), the initial viscosity of the composition after mixing is 40 Pa s or less, preferably 30 Pa s or less, more preferably 20 Pa s or less, more preferably 10 Pa s or less.

[0032] In the present invention, the loading factor is the total amount of thermally conductive filler / total weight of the composition. Generally, a loading factor of 0.84 or higher is considered to be high.

[0033] In the present invention, component (C) is a thermally conductive filler. Component (C) comprises: 10 to 30% by weight (C-1) of aluminum hydroxide having an average particle size of 0.1 μm or more and 4 μm or less; For example, in (C-1), the average particle size is 0.8, 1.0, 1.2, 1.4, 1.6, 1.8, 2.0, 2.2, 2.4, 2.6, and 2.8 μm, and the content is 18 wt%, 20 wt%, 22 wt%, 24 wt%, 26 wt%, and 28 wt%, 10 to 30% by weight (C-2) of aluminum hydroxide having an average particle size of 15 μm or more and 40 μm or less; For example, in (C-2), the average particle size is 18, 20, 22, 24, 26, 28, and 30 μm, and the content is 18 wt%, 20 wt%, 22 wt%, 24 wt%, 26 wt%, and 28 wt%, 40 to 80% by weight (C-3) of aluminum hydroxide having an average particle size of 80 μm or more and 100 μm or less; For example, in (C-3), the average particle size is 82, 84, 86, 88, 90, 92, 94, 96, and 98 μm, and the content is 44 wt%, 46 wt%, 48 wt%, 50 wt%, 52 wt%, 54 wt%, 56 wt%, 58 wt%, 60 wt%, 62 wt%, and 64 wt%, In (C-1), (C-2) and (C-3), the component (C) in the composition is calculated as 100% by weight.

[0034] In the above composition, the total amount of all aluminum hydroxide is greater than 95% by weight, preferably greater than 99% by weight, and more preferably greater than 99.9% by weight, calculated assuming the total amount of thermally conductive fillers to be 100% by weight.

[0035] In the above compositions, the total amount of all aluminum hydroxide is greater than 95% by weight, preferably greater than 99% by weight, and more preferably greater than 99.9% by weight, calculated as 100% by weight of the total amount of fillers.

[0036] In the above compositions, (C-1), (C-2) and (C-3) aluminum hydroxides are all in amorphous form.

[0037] In the above composition, the amount of spherical filler is less than 10% by weight, preferably less than 1% by weight, calculated on the weight of the composition being 100% by weight.

[0038] In the above composition, the amount of spherical alumina is less than 10% by weight, preferably less than 1% by weight, based on 100% by weight of the composition.

[0039] In the above compositions, the content of Al(OH)3 in the aluminum hydroxides (C-1), (C-2) and (C-3) is 99.1% or more, preferably 99.5% or more.

[0040] In the above compositions, the content of Na2O in aluminum hydroxide (C-1), (C-2) and (C-3) is 0.1% or less, and preferably the total content of water-soluble Na2O and lattice-state Na2O is 0.1% or less.

[0041] In the above composition, component (C) is 10 to 30% by weight (C-1) of aluminum hydroxide having an average particle size of 0.5 μm or more and 3 μm or less; 10 to 30% by weight (C-2) of aluminum hydroxide having an average particle size of 15 μm or more and 40 μm or less; 40-80% by weight (C-3) aluminum hydroxide with an average particle size of 85 μm or more and 95 μm or less In (C-1), (C-2) and (C-3), the component (C) in the composition is calculated as 100% by weight.

[0042] In the above composition, component (C) is 20 to 50 wt. % (C-5) alumina having an average particle size of 1 μm or more and 10 μm or less; 50-80% by weight of alumina (C-6) with an average particle size of 30 μm or more and 95 μm or less In (C-5) and (C-6), the component (C) in the composition is calculated as 100% by weight.

[0043] The definition of the average particle size refers to the cumulative average particle size (D50 median diameter) measured on a volume basis using a particle size analyzer LS 13 320 manufactured by Beckman Coulter.

[0044] (C-1) Prepare the sample by the solution method. Place 0.1 g of sample in 10 ml of absolute ethanol, disperse it by ultrasonication (100 watts), and stir for 2 minutes to completely disperse the sample. Take 2-3 drops of the sample solution and place them in the sample cell of the particle size analyzer.

[0045] Prepare samples (C-2), (C-3), (C-5), and (C-6) (or other thermally conductive fillers with an average particle size of 7 μm or greater) using the dry powder method. Place an appropriate amount of the sample, dried at room temperature, into the loading cylinder of the particle size analyzer. Insert the loading cylinder into the detection slot of the device.

[0046] In the present invention, the particle size distribution of the thermally conductive fillers is unimodal, or their particle sizes satisfy a unimodal or nearly unimodal particle size distribution.

[0047] In the present invention, an almost unimodal particle size distribution means that, although there may be two or more peaks in the volume integral map of the measured sample, the volume integral area of ​​the main peak accounts for more than 80%, preferably more than 85%, more preferably more than 90%, more preferably more than 95% of the total volume integral area.

[0048] Spherical fillers, which are generally spherical in shape, are filler materials obtained from amorphous fillers that have been treated by chemical and / or physical (including heat treatment) processes.

[0049] Spherical alumina is a product obtained after heat treatment of amorphous alumina, and has an approximately spherical outer shape.

[0050] Additionally, the present invention provides a cured thermally conductive silicone product comprising the cured product of the thermally conductive silicone composition.

[0051] Such a thermally conductive silicone cured product has excellent fluidity and thermal conductivity, and is lightweight.

[0052] As described above, the thermally conductive silicone composition of the present invention precisely adjusts and blends a silicone composition containing a specific organopolysiloxane, hydrogenpolysiloxane, and thermally conductive filler, thereby densely packing the thermally conductive filler into the substrate. This makes it possible to provide a thermally conductive silicone composition that produces a lightweight thermally conductive cured silicone product with high thermal conductivity. Such thermally conductive silicone cured products are useful as thermally conductive materials in potting applications, particularly for thermal conduction cooling of electronic components.

[0053] As described above, the present invention creates a thermally conductive silicone cured product (thermally conductive gel molded product) that is low in viscosity, low in thixotropy, highly fluid, highly thermally conductive, and lightweight, as well as a thermally conductive silicone composition for forming the cured product.

[0054] Specifically, the thermally conductive silicone composition includes: Component (A): organopolysiloxane, preferably component (A-1): alkenyl group-containing organopolysiloxane

[0055] Component (A) is an organopolysiloxane. Component (A) is the main component of the composition of the present invention. The main chain portion is usually composed of repeating basic diorganosiloxane units, but this molecular structure may partially contain a branched structure or may be a cyclic structure. However, from the viewpoint of physical properties such as the mechanical strength of the cured product, it is preferable that the main chain be a linear diorganopolysiloxane.

[0056] Component (A-1) is an alkenyl-containing organopolysiloxane containing at least two alkenyl groups bonded to silicon atoms per molecule. Component (A-1) functions as the main component of the composition of the present invention. The main chain is typically composed of repeating basic diorganosiloxane units, but this molecular structure may also contain partial branched structures or may be cyclic. However, from the perspective of physical properties such as the mechanical strength of the cured product, it is preferable that the main chain be a linear diorganopolysiloxane.

[0057] The functional group bonded to silicon atom can be exemplified by unsubstituted or substituted monovalent hydrocarbon group.For example, alkyl group, for example, methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, pentyl group, neopentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group and dodecyl group, cycloalkyl group, for example, cyclopentyl group, cyclohexyl group and cycloheptyl group, aryl group, for example, phenyl group, tolyl group, xylyl group, naphthyl group and biphenylyl group, aralkyl group, for example, benzyl group, phenylethyl group, phenylpropyl group and methylbenzyl group, and the groups in which part or all of the hydrogen atoms bonded to carbon atoms of these groups are substituted with cyano group, halogen atoms such as fluorine, chlorine, bromine, etc. Examples of such substituted groups include a chloromethyl group, a 2-bromoethyl group, a 3-chloropropyl group, a 3,3,3-trifluoropropyl group, a chlorophenyl group, a fluorophenyl group, a cyanoethyl group, and a 3,3,4,4,5,5,6,6,6-nonafluorohexyl group. Representative examples of functional groups include those having 1 to 10 carbon atoms, with particularly representative examples including those having 1 to 6 carbon atoms. Preferred examples of functional groups include unsubstituted or substituted alkyl groups having 1 to 3 carbon atoms, such as a methyl group, an ethyl group, a propyl group, a chloromethyl group, a bromoethyl group, a 3,3,3-trifluoropropyl group, and a cyanoethyl group, as well as unsubstituted or substituted phenyl groups, such as a phenyl group, a chlorophenyl group, and a fluorophenyl group. Furthermore, the functional groups bonded to the silicon atom do not all need to be the same.

[0058] Furthermore, the alkenyl group typically has about 2 to 8 carbon atoms. Examples include vinyl, allyl, propenyl, isopropenyl, butenyl, hexenyl, and cyclohexenyl groups. Among these, lower alkenyl groups such as vinyl and allyl are preferred, with vinyl being particularly preferred. Note that two or more alkenyl groups are required per molecule, and in order to improve the flexibility of the resulting cured product, it is preferred that the alkenyl groups be bonded only to silicon atoms at the molecular chain terminals.

[0059] The organopolysiloxane of component (A) preferably has a viscosity at 25°C in the range of 10 to 100,000 mPa s, particularly preferably 50 to 50,000 mPa s, more preferably 50 to 20,000 mPa s, and even more preferably 50 to 2,000 mPa s. The organopolysiloxane of component (A) is preferably polydimethylsiloxane.

[0060] Component (A-1): The alkenyl group-containing organopolysiloxane preferably has a viscosity at 25°C of 10 to 100,000 mPa·s, particularly preferably 50 to 10,000 mPa·s, more preferably 50 to 1,000 mPa·s, and even more preferably 50 to 200 mPa·s. A viscosity of 10 mPa·s or higher results in good storage stability of the resulting composition. On the other hand, a viscosity of 100,000 mPa·s or lower results in good stretchability of the resulting composition. Component (A-1) alkenyl group-containing organopolysiloxane is preferably a vinyl-terminated polydimethylsiloxane.

[0061] The organopolysiloxane of component (A) may be used alone or in combination of two or more types with different viscosities.

[0062] The alkenyl group-containing organopolysiloxane of component (A-1) may be used alone or in combination of two or more types with different viscosities.

[0063] Optional ingredient (B): organohydrogenpolysiloxane Component (B) is an organohydrogenpolysiloxane containing at least two, preferably 2 to 100, hydrogen atoms directly bonded to silicon atoms (Si-H groups) per molecule. This component acts as a crosslinker for component (A-1). Specifically, the Si-H groups in component (B) are added to alkenyl groups in component (A-1) through a hydrosilylation reaction promoted by a platinum group metal curing catalyst (component (D)) described below, forming a three-dimensional network structure with a crosslinked structure. Note that component (B) will not cure if it contains fewer than two Si-H groups per molecule.

[0064] The organohydrogenpolysiloxane used can be represented by the following average structural formula (4), but is not limited thereto.

[0065] [ka] In the formula, R' each independently represents a hydrogen atom or an unsubstituted or substituted monovalent hydrocarbon group containing no aliphatic unsaturated bonds, at least two R' are hydrogen atoms, and e represents an integer of 1 or greater.

[0066] Examples of unsubstituted or substituted monovalent hydrocarbon groups that do not contain an aliphatic unsaturated bond and are represented by R' other than hydrogen in formula (4) include alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, heptyl, octyl, nonyl, decyl, and dodecyl groups; cycloalkyl groups such as cyclopentyl, cyclohexyl, and cycloheptyl groups; aryl groups such as phenyl, tolyl, xylyl, naphthyl, and biphenylyl groups; aralkyl groups such as benzyl, phenylethyl, phenylpropyl, and methylbenzyl groups; and groups in which some or all of the hydrogen atoms bonded to carbon atoms of these groups have been substituted with cyano groups or halogen atoms such as fluorine, chlorine, or bromine. Examples of such substituted groups include chloromethyl, 2-bromoethyl, 3-chloropropyl, 3,3,3-trifluoropropyl, chlorophenyl, fluorophenyl, cyanoethyl, and 3,3,4,4,5,5,6,6,6-nonafluorohexyl. Representative examples of monovalent hydrocarbon groups include those having 1 to 10 carbon atoms, with particularly representative examples including those having 1 to 6 carbon atoms. Preferred examples of monovalent hydrocarbon groups include unsubstituted or substituted alkyl groups having 1 to 3 carbon atoms, such as methyl, ethyl, propyl, chloromethyl, bromoethyl, 3,3,3-trifluoropropyl, and cyanoethyl, as well as unsubstituted or substituted phenyl groups, such as phenyl, chlorophenyl, and fluorophenyl. Furthermore, all R's do not necessarily have to be the same.

[0067] The amount of component (B) added is such that the amount of Si-H groups derived from component (B) is 0.1 to 5.0 moles per mole of alkenyl groups derived from component (A-1) (the number of moles of hydrogen atoms directly bonded to silicon atoms is 0.1 to 5.0 times the number of moles of alkenyl groups derived from component (A-1)), preferably 0.3 to 2.0 moles, and more preferably 0.5 to 1.0 moles. If the amount of Si-H groups derived from component (B) is less than 0.1 mole per mole of alkenyl groups derived from component (A-1), curing may not occur or the strength of the cured product may be insufficient, causing the molded product to be unable to maintain its shape and making it difficult to handle. On the other hand, if the amount exceeds 5.0 moles, the cured product may be inflexible and brittle.

[0068] The organopolysiloxane of component (B) may be used alone or in combination of two or more types with different viscosities.

[0069] In the above composition, component (B) can include (B-1) and (B-2).

[0070] Component (B-1) organic hydrogen-containing polysiloxane is an organic hydrogen-containing polysiloxane having at least three, and preferably 3 to 100, hydrogen atoms (Si-H groups) directly bonded to silicon atoms in each molecule, and the hydrogen content is 0.5 to 4 mmol / g, preferably 0.8 to 3 mmol / g, more preferably 1.1 to 2.7 mmol / g, and more preferably 1.5 to 2.3 mmol / g.

[0071] The organic hydrogen-containing polysiloxane of component (B-2) is an organic hydrogen-containing polysiloxane having two hydrogen atoms directly bonded to silicon atoms (Si-H groups) per molecule, and the hydrogen content is 0.01 to 1.5 mmol / g, preferably 0.1 to 1.2 mmol / g, more preferably 0.3 to 1.0 mmol / g, and more preferably 0.4 to 0.8 mmol / g.

[0072] In the above composition, component (B) contains (B-1) and (B-2), and the amount of component (B-1) is 0.5 to 3% by weight, preferably 1.5 to 2.5% by weight, based on component (A-1) calculated as 100% by weight.

[0073] In the above composition, component (B) contains (B-1) and (B-2), and the amount of component (B-2) is 10 to 50% by weight, preferably 20 to 40% by weight, based on component (A-1) calculated as 100% by weight.

[0074] Component (C): Thermally conductive filler Thermally conductive fillers generally do not contain fumed or precipitated silica.

[0075] In the compositions of the present invention, the content of fumed silica and / or precipitated silica is less than 1% by weight, preferably less than 0.1% by weight, calculated on 100% by weight of the total composition, and the BET specific surface area of ​​the fumed silica or precipitated silica is between 150 and 600 m 2 / g.

[0076] Thermally conductive fillers include materials commonly considered to be thermally conductive fillers, including metals, metal oxides, metal nitrides, and metal hydroxides, as well as non-magnetic metals such as silver, copper, and aluminum; metal oxides such as alumina, silica, magnesia, red iron oxide, beryllia, titania, and zirconia; metal nitrides such as aluminum nitride, silicon nitride, and boron nitride; metal hydroxides such as aluminum hydroxide, magnesium hydroxide, artificial diamond, and silicon carbide. Particle sizes of 0.1 to 200 μm can be used. One or more of these may be used as a composite.

[0077] Component (C) should be blended in an amount of 800 to 4,000 parts by mass, preferably 900 to 2,000 parts by mass, and more preferably 900 to 1,500 parts by mass per 100 parts by mass of component (A). If this blending amount is less than 800 parts by mass, the resulting composition will have insufficient thermal conductivity. If the blending amount exceeds 2,000 parts by mass, kneading workability will be impaired and the cured product will become significantly brittle. To obtain higher thermal conductivity and a lightweight product, the filling factor of the composition is usually 0.84 or higher.

[0078] Optional component (D): Platinum group metal curing catalyst Component (D) is a platinum group metal-based curing catalyst, and is not particularly limited as long as it promotes the addition reaction between the alkenyl group derived from component (A-1) and the Si-H group derived from component (B). Examples of catalysts include well-known catalysts used in hydrosilylation reactions. Specific examples include 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, KHPtCl·nH0, NaPtCl·nH0, KPtCl·nH0, PtCl·nH0, PtCl and NaHPtCl·nH0 (where n is an integer from 0 to 6, preferably 0 or 6); alcohol-modified chloroplatinic acid (U.S. Pat. No. 3,220,972); Nos. 3,159,601, 3,159,662, and 3,775,452), platinum group metals such as platinum black and palladium supported on supports such as alumina, silica, or carbon, rhodium-olefin complexes, chlorotris(triphenylphosphine)rhodium (Wilkinson's catalyst), complexes of platinum chloride, chloroplatinic acid, or chloroplatinate with vinyl group-containing siloxanes, particularly cyclic siloxanes containing no further vinyl groups, and the like.

[0079] Component (D) is used in an amount such that the platinum group metal content is 0.1 to 1,000 ppm by mass relative to component (A-1). If the content is less than 0.1 ppm, sufficient catalytic activity cannot be obtained. If the content exceeds 1,000 ppm, costs will simply increase without improving the effect of accelerating the addition reaction, and residual catalyst in the cured product may reduce insulating properties.

[0080] Component (E-1): An alkoxysilane compound represented by the following formula (1): ·R 1 a R 2 b Si(OR 3 ) 4-a-b (1) In formula (1), ·Each R 1 each independently represents an alkyl group having 1 to 3 carbon atoms, preferably methyl or ethyl; ·Each R 2 each independently represents an unsubstituted or substituted hydrocarbon group having 1 to 3 carbon atoms, preferably an unsubstituted or substituted alkyl group having 1 to 3 carbon atoms, preferably methyl or ethyl; ·Each R 3 each independently represents an alkyl group having 1 to 3 carbon atoms, preferably methyl or ethyl; a represents an integer of 1 to 3, and b represents an integer of 0 to 2, provided that a+b represents an integer of 1 to 3, and preferably a is 1 and b is 0.

[0081] Component (E-1) is preferably an alkoxysilane containing an alkyl group having 1 to 3 carbon atoms, more preferably a trialkoxysilane containing an alkyl group having 1 to 3 carbon atoms, more preferably methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, propyltrimethoxysilane, propyltriethoxysilane, and even more preferably methyltrimethoxysilane or methyltriethoxysilane.

[0082] As a surface treatment agent, component (E-1) can be blended alone or in combination.

[0083] The surface treatment method using component (E-1) and component (E-2) is not particularly limited. The thermally conductive inorganic filler of component (D) can be subjected to, for example, a direct treatment method, an integrated blending method, or a dry concentration method. Direct treatment methods include a dry method, a slurry method, and a spraying method. Integrated blending methods include a direct method and a masterbatch method. Dry methods include a slurry method and a direct method. Preferably, component (D), component (E-1), and component (E-2) are mixed together in advance, either at once or in multiple stages, using a conventional mixing device.

[0084] The surface treatment method using components (E-1) and (E-2) in the present invention is preferably a direct treatment method, and more preferably a thermal surface treatment method in which component (D) is mixed with components (E-1) and (E-2) and heated (base heat). Specifically, component (D) or a portion of component (D) is uniformly mixed with components (E-1), (E-2), and optionally a portion of main component (A) or (B), and then the remaining component (D) is stirred under heating at 100 to 200°C, preferably under reduced pressure, to form a mixture. The temperature conditions and stirring time can be set depending on the amount of sample used, but are preferably 90 to 180°C and 0.25 to 10 hours.

[0085] The mixing device is not particularly limited, and examples thereof include a single-screw or twin-screw continuous mixer, a two-roll mixer, a Ross mixer, a Hobart mixer, a dental mixer, a planetary mixer, a kneader mixer, and a Henschel mixer.

[0086] Component (F): Characterization agent As component (F), an organopolysiloxane having a viscosity of 10 to 100,000 mPa·s at 25°C and represented by the following formula (3) can be added:

[0087] [ka] In the formula, R 5 each independently represents a monovalent hydrocarbon group having 1 to 10 carbon atoms and no aliphatic unsaturated bonds, and d represents an integer of 5 to 2,000.

[0088] Component (F) is used as needed to impart properties such as viscosity modifier and plasticizer to the thermally conductive silicone composition, but is not limited to these. These may be used alone or in combination of two or more.

[0089] Each R 5 R each independently represents an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms. 5Examples of the alkyl group include alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, heptyl, octyl, nonyl, decyl, and dodecyl groups; cycloalkyl groups such as cyclopentyl, cyclohexyl, and cycloheptyl groups; aryl groups such as phenyl, tolyl, xylyl, naphthyl, and biphenylyl groups; aralkyl groups such as benzyl, phenylethyl, phenylpropyl, and methylbenzyl groups; and groups in which some or all of the hydrogen atoms bonded to carbon atoms of these groups have been substituted with cyano groups or halogen atoms such as fluorine, chlorine, or bromine. Examples of such substituted groups include a chloromethyl group, a 2-bromoethyl group, a 3-chloropropyl group, a 3,3,3-trifluoropropyl group, a chlorophenyl group, a fluorophenyl group, a cyanoethyl group, and a 3,3,4,4,5,5,6,6,6-nonafluorohexyl group. Representative examples of monovalent hydrocarbon groups include those having 1 to 10 carbon atoms, and particularly representative examples include those having 1 to 6 carbon atoms. Preferred examples of monovalent hydrocarbon groups include unsubstituted or substituted alkyl groups having 1 to 3 carbon atoms, such as a methyl group, an ethyl group, a propyl group, a chloromethyl group, a bromoethyl group, a 3,3,3-trifluoropropyl group, and a cyanoethyl group, as well as unsubstituted or substituted phenyl groups, such as a phenyl group, a chlorophenyl group, and a fluorophenyl group. A methyl group and a phenyl group are particularly preferred.

[0090] From the viewpoint of the required viscosity, d is preferably an integer of 5 to 2,000, and particularly preferably an integer of 10 to 1,000.

[0091] Furthermore, the viscosity at 25°C is preferably 10 to 100,000 mPa·s, and particularly preferably 100 to 10,000 mPa·s. If the viscosity is 10 mPa·s or higher, the resulting cured product of the composition will be less prone to oil bleeding. If the viscosity is 100,000 mPa·s or lower, the resulting thermally conductive silicone composition will have adequate flexibility.

[0092] When component (F) is added to the thermally conductive silicone composition of the present invention, the amount added is not particularly limited, but can be 10 to 100 parts by mass per 100 parts by mass of component (A). When the amount added is within this range, it becomes easier to maintain good fluidity and operability of the thermally conductive silicone composition before curing, and it becomes easier to fill the composition with the thermally conductive filler of component (C).

[0093] In the thermally conductive silicone composition of the present invention, the amount of component (F) blended is preferably less than 0.1 part by mass, and more preferably less than 0.01 part by mass, per 100 parts by mass of component (A), which prevents oil leakage and contamination of the substrate of the thermally conductive silicone composition.

[0094] Optional ingredient (G): Reaction inhibitor An addition reaction inhibitor can be used as component (G). Any of the known addition reaction inhibitors used in conventional addition reaction curable silicone compositions can be used. Examples include acetylene compounds such as 1-ethynyl-1-hexanol and 3-butyn-1-ol, various nitrogen compounds, organic phosphorus compounds, oxime compounds, and organic chlorine compounds. When component (G) is used, the amount used is preferably 0.01 to 1 part by mass, more preferably 0.1 to 0.8 parts by mass, per 100 parts by mass of component (A-1). This amount ensures that the curing reaction proceeds sufficiently and does not impair molding efficiency.

[0095] Other ingredients The thermally conductive silicone composition of the present invention may further contain other components as needed. Examples of optional components that can be added include heat resistance improvers such as iron oxide and cerium oxide, colorants, and release agents. [Example]

[0096] Embodiment Thermally conductive silicone cured product and its manufacturing method The thermally conductive silicone cured product (thermally conductive resin molded product) of the present invention is a cured product of the above-mentioned thermally conductive silicone composition. The curing conditions for curing (molding) the thermally conductive silicone composition can be the same as those for known addition reaction curable silicone rubber compositions. For example, the thermally conductive silicone composition will cure sufficiently at room temperature, but may be heated if necessary. Preferably, the thermally conductive silicone composition is addition cured at 100 to 120°C for 8 to 12 minutes. Such a cured product (molded product) of the present invention has excellent thermal conductivity.

[0097] Thermal conductivity of molded products The molded article of the present invention preferably has a thermal conductivity of 2.0 W / m K or more as measured by the hot disc method at 25°C. Products with a thermal conductivity of 2.0 W / m K or more are suitable for use in heat-generating components that generate a large amount of heat. This thermal conductivity can be adjusted by adjusting the type or particle size of the thermally conductive filler.

[0098] Hardness of molded product The molded article of the present invention is tested using a Zwick hardness tester. The hardness can be adjusted by changing the ratio of component (A-1) to component (B) to adjust the crosslink density.

[0099] The kinematic and static viscosity of the compositions of the present invention were tested according to DIN 53019 using an Anton Paar MCR302 instrument.

[0100] Components (A) to (G) used in the following examples and comparative examples are shown below.

[0101] Component (A): Component (A-1): An organopolysiloxane represented by the following formula (5), where X represents a vinyl group and n represents a number that results in a viscosity of 120 mPa·s.

[0102] [ka]

[0103] Ingredient (B): (B-1) A side chain hydrogen polysiloxane represented by the following formula (6), having a hydrogen content of 1.7 mmol / g.

[0104] [ka]

[0105] (B-2) A hydrogen-terminated polysiloxane represented by the following formula (7) (wherein X represents hydrogen), having a hydrogen content of 0.53 mmol / g.

[0106] [ka]

[0107] Ingredients (C): (C-1) Aluminum hydroxide with an average particle size of 1.5 μm (C-2) Aluminum hydroxide with an average particle size of 25 μm (C-3) Aluminum hydroxide with an average particle size of 90 μm (C-5) Alumina with an average particle size of 5 μm (C-6) Alumina with an average particle size of 40 μm

[0108] Ingredients (E-2): One-end hydroxyl silicone oil 1 R 1 3SiO-(R 1 2SiO) m -Si-R 1 (3-n) R 2 n (2) In equation (2), R 1 is methyl and R 2 is hydroxy, m is 9 to 15, and n=1; The viscosity is 15-30 mPa.s, the Mn is 700-1200 g / mol according to NMR measurements, and the hydroxyl number is 1.5-2.5 wt%.

[0109] Ingredients (G): Ethynylmethylidenecarbinol as an addition reaction inhibitor. The above materials are provided by Wacker Chemie.

[0110] The components were added in the prescribed amounts shown in the Examples and Comparative Examples in Table 1 or Table 2, and kneaded using a planetary mixer at 90°C for 30 to 60 minutes.

[0111] Molding method After mixing, the composition in Table 1 is obtained.

[0112] The resulting composition shown in Table 2 was poured into a mold having dimensions of 60 mm x 60 mm x 6 mm and molded using a press molding machine at 100°C for 60 minutes.

[0113] Thermal conductivity evaluation method: The obtained compositions of Tables 1 and 2 were poured into a mold having a size of 60 mm x 60 mm x 6 mm and used to measure thermal conductivity.

[0114] The compositions obtained in the following Examples and Comparative Examples in Table 2 were cured at 100°C for 60 minutes to form 6 mm thick sheets. Using two sheets of each composition, the thermal conductivity was measured using a thermal conductivity meter (product name: TC3000E, manufactured by Xi'an Xiatech Electronics Co., Ltd.).

[0115] hardness: The compositions obtained in the following Examples and Comparative Examples were cured into 6 mm thick sheets as described above. Two sheets from each composition were stacked on top of each other and measured with a Zwick hardness tester to obtain Shore 00 values.

[0116] density: Measurements were performed using a METTLER TOLEDO ML204.

[0117] [Table 1]

[0118] Table 2

Claims

1. A composition comprising: Component (A) is an organopolysiloxane, preferably component (A-1) is an organopolysiloxane having two or more alkenyl groups per molecule; optionally, component (B) is an organohydrogenpolysiloxane having two or more hydrogen atoms directly bonded to silicon atoms, and is contained in an amount such that the number of moles of hydrogen atoms directly bonded to silicon atoms in component (B) is 0.1 to 5.0 times the number of moles of alkenyl groups derived from component (A-1); Component (C) is a thermally conductive filler, wherein the filling rate of the thermally conductive filler is 0.80 or more, preferably 0.84 or more, preferably 0.88 or more, preferably 0.89 or more, preferably 0.90 or more; Optionally, component (D) is a platinum group metal curing catalyst having a platinum group metal element content of 0.1 to 1,000 ppm by weight relative to component (A-1); Component (E-1), which is an alkoxysilane compound represented by the following formula (1): R １ ａ R ２ ｂ Si(OR ３ ) ４－ａ－ｂ (1) [In formula (1), Each R １ independently represent an alkyl group having 1 to 3 carbon atoms, preferably methyl or ethyl; Each R ２ each independently represents an unsubstituted or substituted hydrocarbon group having 1 to 3 carbon atoms, preferably methyl or ethyl; Each R ３ independently represent an alkyl group having 1 to 6 carbon atoms, preferably an alkyl group having 1 to 3 carbon atoms, more preferably methyl or ethyl; a represents an integer of 1 to 3, b represents an integer of 0 to 2, and a+b represents an integer of 1 to 3. and Component (E-2) is a polysiloxane represented by the following general formula (2): R １ ３ SiO-(R １ ２ Yes) ｍ -Yes-R １ （３－ｎ） R ２ ｎ (2) [In formula (2), Each R １ independently represent a hydrocarbon group having 1 to 6 carbon atoms, preferably an alkyl or alkenyl group having 1 to 3 carbon atoms, preferably methyl, ethyl, propyl, vinyl, more preferably methyl; Each R ２ are independently —OH or —(CH ２ ) ｐ OH, p is an integer of 1 to 3, and R ２ is preferably hydroxyl, m≦50, more preferably m≦20, more preferably 6≦m≦18; n is an integer, preferably 1 to 3, and more preferably 1.

2. The composition of claim 1, wherein the thixotropy index (Ti) at 25°C is preferably 1.70 or less, preferably 1.05 to 1.70, more preferably 1.20 to 1.70, more preferably 1.30 to 1.

55.

3. 3. The composition according to claim 1 or 2, wherein the viscosity of component (E-2) at 25°C according to DIN 53019 is 500 mPa s or less, preferably 300 mPa s or less, more preferably 100 mPa s or less, more preferably 50 mPa s or less, more preferably 10 to 40 mPa s.

4. The composition according to any one of claims 1 to 3, wherein component (E-1) is preferably an alkoxysilane containing an alkyl group having 1 to 3 carbon atoms, more preferably a trialkoxysilane containing an alkyl group having 1 to 3 carbon atoms, more preferably methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, propyltrimethoxysilane, propyltriethoxysilane, more preferably methyltrimethoxysilane, methyltriethoxysilane.

5. The composition according to any one of claims 1 to 4, wherein the ratio of the component (E-1) to the component (C) is 0.02 to 1.00 wt%, preferably 0.05 to 0.50 wt%, more preferably 0.08 to 0.20 wt%, and more preferably 0.08 to 0.15 wt%.

6. The composition according to any one of claims 1 to 5, wherein the weight ratio of the component (E-2) to the component (E-1) is 0.5 to 10, preferably 0.8 to 6, preferably 2 to 4, and more preferably 2.5 to 3.

5.

7. The composition according to any one of claims 1 to 6, wherein the ratio of the component (E-2) to the component (C) is 0.05 to 1.00 wt%, preferably 0.08 to 0.80 wt%, more preferably 0.08 to 0.60 wt%, and more preferably 0.10 to 0.40 wt%.

8. The composition according to any one of claims 1 to 7, wherein the ratio of the total of components (E-1) and (E-2) to component (C) is 0.05 to 2.00% by weight, preferably 0.08 to 1.20% by weight, more preferably 0.10 to 1.00% by weight, more preferably 0.10 to 0.80% by weight, and more preferably 0.20 to 0.60% by weight.

9. Use of the composition according to any one of claims 1 to 8 in the field of potting.

10. A thermally conductive member comprising the composition according to any one of claims 1 to 8 or a cured product thereof.

11. A heat dissipation structure comprising the heat conduction member according to claim 10.

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