Thermal radical curable thermoconductive silicone composition, and method for producing the same

Abstract

To provide a high thermoconductive silicone composition that has excellent curing properties in heating at a low temperature in short time.SOLUTION: A thermal radical curable thermoconductive silicone composition contains addition reaction product of the following component (A) and component (B), thermoconductive filler (C) having 10 W / m K or more of thermal conductivity by 20 to 95 mass% for the whole composition, platinum group metal catalyst (D), organic peroxide (E) by 1 to 10 pts.mass for 100 pts.mass of the component (A), where (A) is organopolysiloxane which has 10 to 100,000 mm2 / s of kinetic viscosity at 25°C and contains one or more aliphatic unsaturated groups in one molecule, (B) is polyorganohydrogensiloxane which has one or more hydrogen atoms bonded to silicon atoms in one molecule, and has at least one or more groups of acrylate group and methacrylate group, and the number of hydrogen atoms bonded to silicon atoms in the component (B) / the number of aliphatic unsaturated groups in the component (A) is 0.1 to 3.0.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a thermally radically curable, heat-conductive silicone composition that exhibits excellent curability, and a method for producing the same. [Background technology]

[0002] It is widely known that semiconductor elements generate heat during use and the performance is reduced as a result, and various heat dissipation technologies are used as a means to solve this problem. In general, a cooling member (such as a heat sink) is placed near the heat generating part, and the two are placed in close contact with each other, and then the heat is efficiently removed from the cooling member to dissipate heat. In this case, if there is a gap between the heat generating part and the cooling member, the heat conductivity decreases due to the presence of air with poor thermal conductivity, and the temperature of the heat generating part does not drop sufficiently. In order to prevent this phenomenon, heat dissipation materials that have good thermal conductivity and conform to the surface of the part, such as heat dissipation grease and heat dissipation sheets, are used. In addition, heat dissipation grease that hardens into an elastomer material when heated is widely known, and is widely used because it achieves both low thermal resistance and low stress. On the other hand, due to the increase in the number of semiconductors in recent years, the tact time required for hardening can no longer be ignored. In Patent Document 1, high heat dissipation and strong adhesion are achieved by using a platinum catalyst and a peroxide in combination, but looking at the examples, a long heating and hardening time at a high temperature of 150°C for 60 minutes is required, which is not sufficient. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2019 / 138991 Summary of the Invention [Problem to be solved by the invention]

[0004] Prior art silicone compositions suffer from the problem of requiring long heat curing times at high temperatures. The present invention has been made in order to solve the above problems, and has as its object to provide a highly thermally conductive silicone composition that exhibits excellent curing properties when heated at low temperature for a short period of time, and a method for producing the same. [Means for solving the problem]

[0005] In order to solve the above problems, the present invention provides a thermally radically curable, thermally conductive silicone composition, comprising: an addition reaction product of the following components (A) and (B); (C) 20 to 95 mass% of a thermally conductive filler having a thermal conductivity of 10 W / m K or more relative to the total mass of the composition; (D) a platinum group metal catalyst; and (E) 1 to 10 mass parts of an organic peroxide relative to 100 mass parts of component (A); (A) has a kinetic viscosity of 10 to 100,000 mm at 25°C 2 / s, and containing one or more aliphatic unsaturated groups in one molecule; The present invention provides a thermally radically curable, heat-conductive silicone composition in which (B) is a polyorganohydrogensiloxane having, per molecule, one or more hydrogen atoms bonded to silicon atoms and at least one or more groups selected from the group consisting of an acrylate group and a methacrylate group, and the ratio of the number of hydrogen atoms bonded to silicon atoms in component (B) to the number of aliphatic unsaturated groups in component (A) is 0.1 to 3.0.

[0006] Such a thermally radically curable, heat-conductive silicone composition can be cured by heating at a low temperature for a short period of time.

[0007] The thermally radically curable, heat-conductive silicone composition may further contain (F) an organic compound having one or more allyl groups.

[0008] Such a thermally radically curable, heat-conductive silicone composition further improves the adhesive performance of the composition.

[0009] Furthermore, the thermally radically curable, heat-conductive silicone composition may further contain (G) an organic compound having a trialkoxysilyl group.

[0010] Such a thermally radically curable, heat-conductive silicone composition further improves the adhesive performance of the composition.

[0011] The thermally radically curable, heat-conductive silicone composition may further contain (H) a condensation catalyst.

[0012] If the thermally radically curable heat-conductive silicone composition contains such a condensation catalyst, it is possible to accelerate the curing caused by moisture.

[0013] Next, the present invention can provide a method for producing a thermally radically curable, heat-conductive silicone composition, in which components (A), (B), (C), and (D) are heated and mixed at 100°C or higher for 30 minutes or longer, and then cooled, and component (E) is added.

[0014] This method for producing a thermally radically curable, heat-conductive silicone composition makes it possible to produce a thermally radically curable, heat-conductive silicone composition that can be cured at low temperature by heating for a short period of time.

[0015] In this case, the components (A), (B), (C), (D), (G) an organic compound having a trialkoxysilyl group, and (I) a reaction inhibitor are heated and mixed at 100° C. or higher for 30 minutes or longer, cooled, and then It is also possible to provide a method for producing the thermally radically curable, heat-conductive silicone composition, which comprises adding component (E), (F) an organic compound having one or more allyl groups, and (H) a condensation catalyst.

[0016] This method for producing a thermally radically curable, heat-conductive silicone composition makes it possible to produce a thermally radically curable, heat-conductive silicone composition that has superior adhesive strength, superior curability, and can extend the pot life during production of the composition. Effect of the Invention

[0017] As described above, the thermally radically curable, heat-conductive silicone composition of the present invention can provide a silicone composition that has an appropriate thickness and thermal conductivity during practical use, thereby realizing high heat dissipation performance and abrasion resistance. In addition, the composition can be cured by heating at a low temperature for a short period of time. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] As described above, there has been a need for the development of a highly thermally conductive silicone composition that can be cured at low temperature by heating for a short period of time.

[0019] As a result of extensive investigations into the above-mentioned problems, the present inventors discovered that a highly thermally conductive silicone composition with excellent curability can be obtained by combining a thermally conductive filler with a compound obtained by crosslinking an organopolysiloxane of a specific kinematic viscosity and an organohydrogensiloxane having a curable group via a hydrosilylation reaction, and thus arrived at the present invention.

[0020] That is, the present invention relates to a thermally radically curable, thermally conductive silicone composition (hereinafter, simply referred to as silicone composition), which comprises an addition reaction product of the following components (A) and (B), (C) 20 to 95 mass% of a thermally conductive filler having a thermal conductivity of 10 W / m K or more relative to the entire composition, (D) a platinum group metal catalyst, and (E) 1 to 10 parts by mass of an organic peroxide relative to 100 parts by mass of component (A); (A) has a kinetic viscosity of 10 to 100,000 mm at 25°C 2 / s, and containing one or more aliphatic unsaturated groups in one molecule; The thermally radically curable, heat-conductive silicone composition is one in which (B) is a polyorganohydrogensiloxane having, per molecule, one or more hydrogen atoms bonded to silicon atoms and at least one or more groups selected from the group consisting of an acrylate group and a methacrylate group, and the ratio of the number of hydrogen atoms bonded to silicon atoms in component (B) to the number of aliphatic unsaturated groups in component (A) is 0.1 to 3.0.

[0021] The present invention will be described in detail below, but the present invention is not limited thereto.

[0022] Component (A) Component (A) has a kinetic viscosity of 10 to 100,000 mm at 25°C. 2 / s, preferably 30 to 10,000 mm 2 / s, and is an organopolysiloxane containing one or more aliphatic unsaturated groups per molecule. If the kinetic viscosity of the organopolysiloxane is lower than the above lower limit, oil bleeding is likely to occur when the silicone composition is made. If it is higher than the above upper limit, the extensibility of the silicone composition may be poor. In the present invention, the kinetic viscosity of the organopolysiloxane is a value at 25°C measured with an Ostwald viscometer.

[0023] In the present invention, the organopolysiloxane has the above-mentioned kinetic viscosity and contains one or more aliphatic unsaturated groups in one molecule, and any known organopolysiloxane can be used. The molecular structure of the organopolysiloxane is not particularly limited, and may be linear, branched, cyclic, or the like. In particular, it is preferable that the main chain is made of a repeating diorganosiloxane unit, and has a linear structure in which both ends of the molecular chain are blocked with triorganosiloxy groups. The organopolysiloxane may be used alone or in combination of two or more kinds.

[0024] The organopolysiloxane can be represented by the following average composition formula (1). R 1 a SiO (4-a) / 2 (1)

[0025] In the above formula (1), R 1are each independently a saturated or unsaturated, unsubstituted or substituted monovalent hydrocarbon group having 1 to 18 carbon atoms, preferably 1 to 14. Examples of the monovalent hydrocarbon group include alkyl groups such as methyl, ethyl, propyl, hexyl, octyl, decyl, dodecyl, tetradecyl, hexadecyl, and octadecyl, cycloalkyl groups such as cyclopentyl and cyclohexyl, alkenyl groups such as vinyl and allyl, aryl groups such as phenyl and tolyl, aralkyl groups such as 2-phenylethyl and 2-methyl-2-phenylethyl, and groups in which some or all of the hydrogen atoms of these groups have been substituted with halogen atoms such as fluorine, bromine, and chlorine, or with a cyano group, for example, a 3,3,3-trifluoropropyl group, a 2-(perfluorobutyl)ethyl group, a 2-(perfluorooctyl)ethyl group, and a p-chlorophenyl group.

[0026] In the above formula (1), a is a number within the range of 1.8 to 2.2, and particularly within the range of 1.9 to 2.1. By having a within the above range, the resulting silicone composition can have a good viscosity.

[0027] As the organopolysiloxane represented by the above average composition formula (1), a linear organopolysiloxane represented by the following formula (2) is preferred. [ka]

[0028] In the above formula, R 2 are each independently a saturated or unsaturated, unsubstituted or substituted monovalent hydrocarbon group having 1 to 18 carbon atoms, preferably 1 to 14 carbon atoms. Examples of the monovalent hydrocarbon group include the groups described above. Furthermore, at least one R 2 is preferably a vinyl group. 2 The number of carbon atoms is such that the kinematic viscosity of the organopolysiloxane at 25°C is 10 to 100,000 mm 2 / s, preferably 30 to 10,000 mm 2 / s, and more preferably 100 to 8,000 mm 2 / s.

[0029] (B) Component The (B) component is a polyorganohydrogensiloxane having one or more hydrogen atoms bonded to silicon atoms in one molecule and at least one or more groups selected from the group consisting of acrylate and methacrylate groups. The (B) component may be used alone or in combination of two or more. The organohydrogenpolysiloxane is one in which silicon-bonded hydrogen atoms (SiH groups) in the molecule undergo an addition reaction with aliphatic unsaturated hydrocarbon groups in the composition in the presence of a platinum group metal catalyst described below to form a crosslinked structure, and therefore, it is necessary that there be at least one group on average in one molecule. The upper limit is not particularly limited, but is preferably 5 or less, more preferably 3 or less. It is also necessary that there be at least one group on average in one molecule selected from the group consisting of acrylate and methacrylate groups. The upper limit is not particularly limited, but is preferably 5 or less, more preferably 3 or less, and even more preferably 1. It is also possible that there are only a plurality of acrylate groups, or only a plurality of methacrylate groups. The molecular structure of component (B) is not particularly limited and may be, for example, linear, branched, or cyclic, but can be one represented by the average composition formula below.

[0030] [ka] (In the formula, R 3is an unsubstituted or substituted monovalent hydrocarbon group, or a hydrogen atom. They may be different from each other, but at least one is a hydrogen atom. Examples of the monovalent hydrocarbon group include alkyl groups such as methyl, ethyl, propyl, hexyl, octyl, decyl, dodecyl, tetradecyl, hexadecyl, and octadecyl, cycloalkyl groups such as cyclopentyl and cyclohexyl, alkenyl groups such as vinyl and allyl, aryl groups such as phenyl and tolyl, aralkyl groups such as 2-phenylethyl and 2-methyl-2-phenylethyl, and groups in which some or all of the hydrogen atoms of these groups are substituted with halogen atoms such as fluorine, bromine, and chlorine, or cyano groups, such as 3,3,3-trifluoropropyl, 2-(perfluorobutyl)ethyl, 2-(perfluorooctyl)ethyl, and p-chlorophenyl.

[0031] X 1 , X 2 , X 3 is R 1 or -(CH2) n -O(=O)C-CR 4 Each of them may be different, but at least one of them is -(CH2) n -O(=O)C-CR 4 =CH2. R 4 is a hydrogen atom or a methyl group. n is an integer of 1 to 10, preferably an integer of 1 to 5, and more preferably an integer of 2 to 4.

[0032] a and b are respectively 1≦a≦1,000 and 0≦b≦1,000, more preferably 1≦a≦100 and 0≦b≦100, and even more preferably 1≦a≦50 and 0≦b≦50.

[0033] Examples of component (B) include the following.

[0034] B-1: Organohydrogenpolysiloxane represented by the following formula: (Siloxane content: 0.0038 mol / g) [ka]

[0035] B-2: Organohydrogenpolysiloxane represented by the following formula: (Siloxane content: 0.0055 mol / g) [ka]

[0036] B-3: Organohydrogenpolysiloxane represented by the following formula: (Siloxane content: 0.0011 mol / g) [ka] The amount of component (B) is such that the ratio (number of hydrogen atoms bonded to silicon atoms in component (B) / number of aliphatic unsaturated groups in component (A)) is 0.1 to 3.0, and preferably 0.2 to 2.5. If the ratio (number of hydrogen atoms bonded to silicon atoms in component (B) / number of aliphatic unsaturated groups in component (A)) is less than 0.1, the curability becomes insufficient, and if it exceeds 3.0, the curability does not improve and it is uneconomical.

[0037] (C) Component The component (C) is a thermally conductive filler. The component (C) is a thermally conductive filler having a thermal conductivity of 10 W / m·K or more. The thermally conductive filler of the component (C) has a thermal conductivity of 10 W / m·K or more, preferably 15 W / m·K or more. If the thermal conductivity of the filler is less than 10 W / m·K, the thermal conductivity of the thermally conductive silicone composition itself will be small. The upper limit of the thermal conductivity is not particularly limited, but since silver powder, which has the highest thermal conductivity among compounds commonly used as thermally conductive fillers, is 420 W / m·K, it can be set to 420 W / m·K or less. Examples of such thermally conductive fillers include aluminum powder, copper powder, silver powder, iron powder, nickel powder, gold powder, tin powder, metal silicon powder, aluminum nitride powder, boron nitride powder, alumina powder, diamond powder, carbon powder, indium powder, gallium powder, and zinc oxide powder. Any filler having a thermal conductivity of 10 W / m·K or more may be used, and one or a mixture of two or more fillers may be used. The average particle size of component (C) is preferably in the range of 0.1 to 150 μm, more preferably in the range of 0.1 to 120 μm. When the average particle size is 0.1 μm or more, the composition obtained becomes grease-like and has good extensibility, and when it is 150 μm or less, the thermal resistance of the heat dissipation grease does not become excessive and the performance is good. In the present invention, the average particle size can be measured using a Microtrac MT330OEX manufactured by Nikkiso Co., Ltd., and is a volume-average diameter based on volume. The shape of component (C) may be any shape, such as amorphous or spherical. The amount of the thermally conductive filler is 20 to 95% by mass, more preferably 50 to 95% by mass, and more preferably 80 to 95% by mass, based on the entire composition. If it exceeds 95% by mass, the composition will not be uniform, and if it is less than 20% by mass, the heat dissipation properties may be insufficient.

[0038] (D) Component The component (D) is a platinum group metal catalyst, and functions to promote the above-mentioned addition reaction. The platinum group metal catalyst may be any known catalyst used in addition reactions. Examples include platinum-based, palladium-based, and rhodium-based catalysts, among which platinum or platinum compounds, which are relatively easy to obtain, are preferred. Examples include platinum alone, platinum black, chloroplatinic acid, platinum-olefin complexes, platinum-alcohol complexes, and platinum coordination compounds. Platinum-based catalysts may be used alone or in combination of two or more. The amount of the component (D) to be blended may be an effective amount as a catalyst, that is, an effective amount required to promote the addition reaction and cure the composition of the present invention. In particular, the amount of the component (D) is 0.1 to 500 ppm, more preferably 1 to 200 ppm, based on the mass of the platinum group metal atom relative to the component (A). When the amount of the catalyst is equal to or more than the lower limit, the effect of the catalyst can be obtained. Also, when the amount of the catalyst is equal to or less than the upper limit, it is economical and preferable for the catalytic effect.

[0039] (E) Component Component (E) is a radical initiator that generates radicals by heat, and is an important component for thermally radical curing the polyorganosiloxane obtained by crosslinking components (A) and (B) above. The component (E) is not particularly limited as long as it is an organic peroxide, and examples thereof include dicumyl peroxide, 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane, di-t-butyl peroxide, 2,5-di(t-butylperoxy)-2,5-dimethylhexane, 1,1-bis(t-amylperoxy)cyclohexane, 2,2-bis(t-butylperoxy)butane, 2,4-pentanedione peroxide, 2,5-bis(t-butylperoxy)-2,5-dimethylhexane, 2,5-di(t-butylperoxy)-2,5-dimethyl-3-hexyne, 2-butanone peroxide, benzoyl peroxide, cumene hydroperoxide, lauroyl peroxide, t-butyl hydroperoxide, t-butyl peroxy benzoate, t-butylperoxy-2-ethylhexyl carbonate, Examples of organic peroxides include di(2,4-dichlorobenzoyl)peroxide, dichlorobenzoyl peroxide, di(t-butylperoxyisopropyl)benzene, di(4-methylbenzoyl)peroxide, di(2-methylbenzoyl)peroxide, butyl-4,4-di(t-butylperoxy)valerate, 3,3,5,7,7-pentamethyl-1,2,4-trioxepane, t-butylcumyl peroxide, di(4-t-butylcyclohexyl)peroxydicarbonate, dicetyl peroxydicarbonate, 2,3-dimethyl-2,3-diphenylbutane, dioctanoyl peroxide, t-butylperoxy-2-ethylhexyl carbonate, t-amylperoxy-2-ethylhexanoate, 1,6-hexanediol-bis-t-butylperoxycarbonate, and combinations thereof. To improve handling, the composition may be diluted with a solvent or the like, but the 1-minute half-life after dilution is preferably from 50° C. to 180° C., more preferably from 70° C. to 160° C., and even more preferably from 90° C. to 140° C. A 1-minute half-life of 50° C. or more provides good storage stability, while a 1-minute half-life of 180° C. or less provides good curability.As such peroxides, NOF Corp.'s Niper BMT (1-minute half-life 131.1°C), NOF Corp.'s Peroyl TCP (1-minute half-life 92.1°C), and NOF Corp.'s Perhexa C (1-minute half-life 153.8°C) are preferred. The content of component (E) is 1-10 parts by mass, and more preferably 3-7 parts by mass, per 100 parts by mass of component (A). If the content of component (E) is less than 1 part by mass, curing will be insufficient, and if it is more than 10 parts by mass, the curability will not improve and it will be uneconomical.

[0040] Ingredient (F) The component (F) is an organic compound containing one or more allyl groups. Examples of suitable organic compounds for the component (F) include, but are not limited to, allyl methacrylate, allyl acrylate, diallyl maleate, and mixtures thereof. The content of the component (F) is preferably 0.01 to 10 parts by mass, more preferably 2 to 5 parts by mass, per 100 parts by mass of the component (A). When the content of the component (F) is 0.01 parts by mass or more, the surface of the substrate can be sufficiently treated, and good adhesive strength is obtained, and when the content is 10 parts by mass or less, the mechanical properties of the silicone composition are good.

[0041] (G) Component The (G) component is an organic compound having a trialkoxysilyl group. The (G) component can improve the adhesive performance of the composition. Examples of suitable organic compounds include, but are not limited to, organotrialkoxysilanes such as methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, n-butyltrimethoxysilane, n-butyltriethoxysilane, isobutyltrimethoxysilane, n-hexyltrimethoxysilane, and n-decyltrimethoxysilane. 3-methacryloxypropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, and 7-octenyltrimethoxysilane are preferred because they provide excellent adhesive properties due to thermal radical curing of the composition of the present invention. The (G) component may be used alone or in combination of two or more types. The content of component (G) is preferably 0.1 to 10 parts by mass, and more preferably 0.5 to 4.0 parts by mass, per 100 parts by mass of component (A). When the content of component (G) is 0.1 part by mass or more, the alkoxysilane can be sufficiently surface-treated with the substrate surface, and good adhesive strength is obtained, and when it is 10 parts by mass or less, the mechanical properties of the silicone composition are good.

[0042] (H) Component Component (H) is used as a condensation reaction catalyst that accelerates curing by moisture, and examples of such catalysts include Lewis acids, primary, secondary, or tertiary organic amine compounds, metal oxides, organic titanium compounds, organic tin compounds, organic zirconium compounds, and organic carboxylates of metals such as iron, antimony, bismuth, and manganese. Component (H) may be used alone or as a mixture of two or more types.

[0043] Specific examples of the condensation reaction catalyst include dibutyltin dilaurate, dibutyltin dioctoate, dioctyltin dilaurate, dibutyltin malate ester, dimethyltin dineodecanoate, dibutyltin dimethoxide, dioctyltin dineodecanoate, stannous octoate, tetrabutyl titanate, tetra-(2-ethylhexyl) titanate, diisopropoxybis(acetylacetonate)titanium, diisopropoxybis(ethylacetoacetate)titanium, tetramethylguanidylpropyltrimethoxysilane and its salts. Since the curing properties of the composition of the present invention by condensation curing are excellent, it is preferable to add an organic tin compound or an organic titanium compound, and among them, an organic titanium compound, particularly tetra-(2-ethylhexyl) titanate, diisopropoxybis(acetylacetonate)titanium, and diisopropoxybis(ethylacetoacetate)titanium are preferable. The amount of component (H) added is preferably 0.01 to 10% by mass, more preferably 0.05 to 7% by mass, and even more preferably 0.1 to 1% by mass, based on the total composition. If the amount is 0.01% by mass or more, sufficient crosslinking by condensation curing can be obtained. If the amount is 10% by mass or less, it is advantageous in terms of cost and the curing speed is not reduced, so this is preferable.

[0044] Other Ingredients The silicone composition of the present invention may contain (I) a reaction inhibitor. Component (I) is an inhibitor that suppresses the progress of the hydrosilylation reaction at room temperature and functions to extend the pot life during the production of the composition. The reaction inhibitor may be a known reaction inhibitor used in addition curing silicone compositions. Examples of the reaction inhibitor include acetylene compounds such as acetylene alcohols (e.g., ethynylmethyldecylcarbinol, 1-ethynyl-1-cyclohexanol, 3,5-dimethyl-1-hexyn-3-ol), various nitrogen compounds such as tributylamine, tetramethylethylenediamine, and benzotriazole, organic phosphorus compounds such as triphenylphosphine, oxime compounds, and organic chloro compounds. In order to adjust the viscosity of the composition, the composition may contain a non-reactive organo(poly)siloxane such as methylpolysiloxane. In addition, in order to prevent deterioration of the silicone composition, the composition may contain a known antioxidant such as 2,6-di-t-butyl-4-methylphenol, as necessary. Furthermore, dyes, pigments, flame retardants, anti-settling agents, thixotropy improvers, etc. may be blended as necessary.

[0045] Next, methods for producing the silicone composition of the present invention will be described, but the methods are not limited thereto.

[0046] Making the Silicone Composition The method for producing the silicone composition of the present invention may be according to the conventional method for producing silicone grease compositions, and is not particularly limited. For example, the silicone composition of the present invention can be produced by mixing the above components (A) to (H) and other components as necessary with a mixer such as Trimix, Twinmix, Planetary Mixer (all of which are registered trademarks of mixers manufactured by Inoue Seisakusho Co., Ltd.), Ultra Mixer (registered trademark of mixers manufactured by Mizuho Kogyo Co., Ltd.), or Hivis Dispermix (registered trademark of mixers manufactured by Tokushu Kika Kogyo Co., Ltd.). By stirring the above components (A), (B), (C), and (D) at a temperature of 100°C or higher, preferably 110°C, and more preferably 120°C, for 30 minutes or more, the components (A) and (B) are sufficiently crosslinked by hydrosilylation reaction, and the thermally conductive silicone composition can have an appropriate viscosity. The silicone composition of the present invention has high thermal conductivity, and is therefore optimal as a thermally conductive silicone composition. The thermal conductivity is measured by the method described in the Examples below.

[0047] Alternatively, the silicone composition can be prepared by heating and mixing components (A), (B), (C), and (D) at 100°C or higher for 30 minutes or more, cooling, and then adding component (E).In this case, a thermally radically curable heat-conductive silicone composition can also be prepared by heating and mixing components (A), (B), (C), (D), (G), and (I) at 100°C or higher for 30 minutes or more, cooling, and then adding components (E), (F), and (H).

[0048] The silicone composition of the present invention exhibits excellent curing properties and is therefore ideal as a thermally conductive silicone composition. EXAMPLES

[0049] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples. In the following, the kinematic viscosity is a value measured at 25°C using an Ubbelohde-type Ostwald viscometer (manufactured by Shibata Scientific Co., Ltd.).

[0050] Component (A) A-1: Both ends are blocked with dimethylvinylsilyl groups, and the kinetic viscosity at 25°C is 600mm 2 / s dimethylpolysiloxane (vinyl group amount 0.015mol / 100g) A-2: Both ends are blocked with dimethylvinylsilyl groups, and the kinetic viscosity at 25°C is 100,000mm 2 / s dimethylpolysiloxane (vinyl group amount 0.005mol / 100g)

[0051] (B) Component B-1: Organohydrogenpolysiloxane represented by the following formula (hydrogen group amount 0.0038 mol / g) [ka]

[0052] B-2: Organohydrogenpolysiloxane represented by the following formula (hydrogen group amount 0.0051 mol / g) [ka]

[0053] B-3: Organohydrogenpolysiloxane represented by the following formula (hydrogen group amount 0.0011 mol / g) [ka]

[0054] b-4: Organohydrogenpolysiloxane represented by the following formula (hydrogen group amount 0.0054 mol / g) [ka]

[0055] (C) Component C-1: Spherical aluminum oxide with D50 of 10.0 μm (thermal conductivity 33.4 W / m K) C-2: Irregular aluminum oxide with D50 of 1.2 μm (thermal conductivity 21.8 W / m K) C-3: Irregular aluminum nitride with D50 of 20.2 μm (thermal conductivity 180.7 W / m K)

[0056] (D) Component D-1: A solution of platinum-divinyltetramethyldisiloxane complex dissolved in the same dimethylpolysiloxane as A-1 (platinum atom content: 1% by mass)

[0057] (E) Component E-1: Benzoyl peroxide xylene solution (active ingredient 40%), NOF Corp., product name: Niper BMT, 1 minute half-life 131.1℃ E-2: Bis(4-tert-butylcyclohexyl) peroxydicarbonate (90% or more active ingredient) Product name: NOF Peroyl TCP 1 minute half-life 92.1℃

[0058] Ingredient (F) F-1: Allyl methacrylate F-2: Diallyl maleate

[0059] (G) Component G-1: 3-methacryloxypropyltrimethoxysilane, G-2: 7-Octenyltrimethoxysilane

[0060] (H) Component H-1: Diisopropoxybis(ethylacetoacetate)titanium

[0061] Component (I) I-1: Ethynylcyclohexanol

[0062] [Examples 1 to 13, Comparative Examples 1 to 2] Preparation of Silicone Composition The above components (A) to (G) were mixed in the amounts shown in Tables 1 and 2 by the method described below to prepare silicone compositions. Components (A) to (D), (G), and (I) were added to a 5-liter planetary mixer (manufactured by Inoue Seisakusho Co., Ltd.) and mixed at 120°C for 2 hours. The mixture was then cooled to 30°C or less, and components (E), (F), and (H) were added to prepare silicone compositions. The viscosity, thermal conductivity, hardness, shear adhesion (elongation), and surface curability of each composition obtained by the above method were measured according to the methods described below. The results are shown in Tables 1 and 2.

[0063] [Comparative Examples 3 to 5] Preparation of Silicone Composition The above components (A), (C), and (G) were mixed for 2 hours at 120°C according to the amounts shown in Table 3 below. The mixture was then cooled to below 30°C, and components (B), (D), (E), (F), (H), and (I) were added to prepare a silicone composition. The viscosity, thermal conductivity, hardness, shear adhesion (elongation), and surface curability of each composition obtained by the above method were measured according to the following methods. The results are shown in Table 3.

[0064] [Viscosity measurement] The viscosity of the silicone composition was measured at 25° C. using a spiral viscometer (Type PC-1T) manufactured by Malcom Co., Ltd. (rotor A at 10 rpm, shear rate 6 [1 / s]).

[0065] [Measurement of thermal conductivity] Each composition was wrapped in kitchen wrap to form a pouch, and the thermal conductivity of the pouch was measured using a Kyoto Electronics Manufacturing Co., Ltd. TPA-501.

[0066] [Hardness measurement] Each composition was heated at 100° C. for 15 minutes, cured, and cut into a 6 mm sheet, which was then measured with a Shore A durometer.

[0067] [Shear adhesion measurement] Each composition was sandwiched between two aluminum plates with a thickness of 1 mm x 25 mm x 2 mm, heated at 100°C for 15 minutes to harden, and the stress when cut was measured.

[0068] [Confirmation of surface hardening] 20 g of the composition was placed in an aluminum petri dish with a diameter of 60 mm, heated at 100° C. for 15 minutes, removed, and the hardening of the surface was confirmed after 24 hours.

[0069] [Table 1]

[0070] [Table 2]

[0071] [Table 3]

[0072] From Tables 1 and 2, the silicone compositions of Examples 1 to 13, which satisfy the requirements of the present invention, have excellent heat dissipation adhesion properties after a curing time of 100°C for 15 minutes. Furthermore, when comparing Examples 1 to 8 and 10 to 13, which contain the component (H-1), with Example 9, which does not contain the component (H-1), it is found that the addition of the optional condensation catalyst results in excellent surface curing properties in addition to heat dissipation adhesion properties. On the other hand, from Tables 1 and 3, Comparative Examples 1 to 5, which do not satisfy the requirements of the present invention, are insufficiently cured and do not have adhesion properties. Comparative Example 2 does not cure, and the other cured Comparative Examples also have low hardness and low shear adhesion values. Therefore, the present invention can provide a thermally radical curable heat conductive silicone composition that cures well at low temperatures and for a short time under heating, and has excellent heat dissipation adhesion properties.

[0073] The present specification includes the following aspects. [1]: A thermally radically curable thermally conductive silicone composition comprising: an addition reaction product of the following components (A) and (B); (C) 20 to 95 mass% of a thermally conductive filler having a thermal conductivity of 10 W / m K or more relative to the total mass of the composition; (D) a platinum group metal catalyst; and (E) 1 to 10 mass parts of an organic peroxide relative to 100 mass parts of component (A); (A) has a kinetic viscosity of 10 to 100,000 mm at 25°C 2 / s, and containing one or more aliphatic unsaturated groups in one molecule; A thermally radically curable, heat-conductive silicone composition in which (B) is a polyorganohydrogensiloxane having one or more hydrogen atoms bonded to silicon atoms in each molecule and having at least one or more groups selected from the group consisting of an acrylate group and a methacrylate group, wherein the ratio of the number of hydrogen atoms bonded to silicon atoms in component (B) to the number of aliphatic unsaturated groups in component (A) is 0.1 to 3.0. [2]: The thermally radically curable, heat-conductive silicone composition according to [1], further comprising (F) an organic compound having one or more allyl groups. [3]: The thermally radically curable, heat-conductive silicone composition according to [1] or [2], further comprising (G) an organic compound having a trialkoxysilyl group. [4]: The thermally radically curable, heat-conductive silicone composition according to any one of [1] to [3], further comprising (H) a condensation catalyst. [5]: A method for producing a thermally radically curable, heat-conductive silicone composition according to [1], characterized in that components (A), (B), (C), and (D) are heated and mixed at 100°C or higher for 30 minutes or longer, cooled, and then component (E) is added. [6]: A method for producing a thermally radically curable, heat-conductive silicone composition according to [5], characterized in that the components (A), (B), (C), and (D), (G) an organic compound having a trialkoxysilyl group, and (I) a reaction inhibitor are heated and mixed at 100°C or higher for 30 minutes or longer, and then cooled, and the component (E), (F) an organic compound having one or more allyl groups, and (H) a condensation catalyst are added.

[0074] The present invention is not limited to the above-described embodiment. The above-described embodiment is merely an example, and anything that has substantially the same configuration as the technical idea described in the claims of the present invention and exhibits similar effects is included in the technical scope of the present invention.

Claims

1. A thermally radically curable, thermally conductive silicone composition comprising an addition reaction product of the following components (A) and (B): (C) 20 to 95 mass % of a thermally conductive filler having a thermal conductivity of 10 W / m K or more relative to the entire composition; (D) a platinum group metal catalyst; and (E) 1 to 10 mass parts of an organic peroxide relative to 100 mass parts of component (A); (A) has a kinetic viscosity at 25°C of 10 to 100,000 mm ２ / s, an organopolysiloxane containing one or more aliphatic unsaturated groups in one molecule; The thermally radically curable, heat-conductive silicone composition is one in which (B) is a polyorganohydrogensiloxane having, per molecule, at least one hydrogen atom bonded to a silicon atom and at least one or more groups selected from the group consisting of an acrylate group and a methacrylate group, and the ratio of the number of hydrogen atoms bonded to silicon atoms in component (B) to the number of aliphatic unsaturated groups in component (A) is 0.1 to 3.

0.

2. 2. The thermally radically curable, heat-conductive silicone composition according to claim 1, further comprising (F) an organic compound having one or more allyl groups.

3. 2. The thermally radically curable, heat-conductive silicone composition according to claim 1, further comprising (G) an organic compound having a trialkoxysilyl group.

4. The thermally radically curable, heat-conductive silicone composition according to claim 1, further comprising (H) a condensation catalyst.

5. 2. The method for producing a thermally radically curable, heat-conductive silicone composition according to claim 1, characterized in that components (A), (B), (C), and (D) are heated and mixed at 100° C. or higher for 30 minutes or longer, and then cooled, and component (E) is added.

6. The components (A), (B), (C), and (D), the organic compound having a trialkoxysilyl group (G), and the reaction inhibitor (I) are mixed at 100° C. or higher for 30 minutes or longer, cooled, and then:

6. The method for producing a thermally radically curable, heat-conductive silicone composition according to claim 5, further comprising the addition of component (E), (F) an organic compound having one or more allyl groups, and (H) a condensation catalyst.

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