JP5278943B2 - Thermosetting silicone rubber composition, electronic component and electronic device - Google Patents

Description

The present invention relates to a thermosetting silicone rubber composition, and more specifically, a curable silicone rubber composition that has a small increase in viscosity at room temperature and excellent handling workability, and that is quickly cured by heating at a low temperature, and The present invention relates to an electronic component and an electronic device coated and bonded with the thermosetting silicone rubber composition.

Addition reaction type thermosetting silicone rubber composition that cures organo-polysiloxane containing silicon-bonded alkenyl group and organohydrogenpolysiloxane containing silicon-bonded hydrogen atom with platinum-based catalyst has excellent coating workability. As a highly reliable material having adhesiveness, curability, heat stability, electrical characteristics, heat conduction characteristics, etc., capacitors, resistors, diodes, memories, arithmetic components (CPU) and other electronic components, and coatings for electronic devices It is widely used as a heat-dissipating agent and adhesive.

In recent years, display devices such as liquid crystal and plasma have been improved in performance as electronic components, electronic equipment, and electronic devices mounted due to their upsizing, and their mounting positions have been increased by high-density mounting. Since it has become extremely close, the heat resistance restrictions of the parts and devices used in these devices have a great influence. As a result, the upper limit temperature of the thermosetting silicone rubber composition used is, for example, 70 to The restriction of being limited to 100 ° C. is becoming stronger. In addition, from the viewpoint of high-density mounting, there is no room for area in the vicinity of the parts where the thermosetting silicone rubber composition is used, and it is also necessary to cure quickly after application etc. and not spread around the periphery. Has been.

On the other hand, from the viewpoint of workability, the thermosetting silicone rubber composition is a one-component type that suppresses the reaction at room temperature, suppresses the increase in viscosity, keeps the pot life longer, and does not require any mixing work before use. There continues to be a need.
As described above, thermosetting having a contradictory curing characteristic is that the curing reaction is extremely slow at room temperature (working atmosphere temperature, for example, 25 ° C.) and that curing is rapid at the curing temperature (for example, 70 to 100 ° C.). There is an increasing demand for silicone rubber compositions.

In order for the thermosetting silicone rubber composition to cure quickly at a low heating temperature, a platinum-based catalyst that is liquid at room temperature, specifically, an alcohol solution of chloroplatinic acid, platinum and low-viscosity divinyltetramethyldisiloxane Complexes and the like are suitably used, and if the addition amount is increased, a thermosetting silicone rubber composition that can be rapidly cured even at a low curing temperature can be obtained. However, in this case, at the same time, the pot life at room temperature rapidly decreases, the working efficiency of coating is remarkably reduced, and it becomes difficult to obtain a thermosetting silicone rubber composition having a one-part product form.

On the other hand, for the purpose of extending the pot life at room temperature and reducing the influence of curing inhibition by contained substances and surrounding substances, for example, from a thermoplastic resin containing a platinum-based catalyst having a softening point of 40 to 200 ° C. A particulate catalyst has been proposed (Japanese Patent Laid-Open No. 8-319425). By using a thermoplastic resin having a softening point to form fine particles, it is possible to have a one-component and long pot life. However, at the curing temperature, the thermoplastic resin is only softened so that it can be cured. There is a problem that the release rate and diffusion of effective platinum-based catalyst components are slow, and particularly when the curing temperature is low (for example, 70 to 100 ° C.), the curing rate cannot be increased.

JP-A-8-319425

As a result of earnestly examining the form of the platinum-based catalyst used in the thermosetting silicone rubber composition in order to solve such a problem, by forming a fine particle composed of a platinum-based catalyst and a wax having a melting point in a specific range, It has been found that a thermosetting silicone rubber composition that can be cured in a short time by heating at a low temperature (for example, 70 to 100 ° C.) can be obtained because the increase in viscosity is small at room temperature. The present invention has been reached.
An object of the present invention is a thermosetting silicone rubber composition using a platinum-based catalyst that has a long pot life at room temperature and can be cured in a short time by heating at a low temperature (for example, 70 to 100 ° C.), Another object of the present invention is to provide an electronic component and an electronic device that are coated and bonded with the thermosetting silicone rubber composition.

The present invention
(A) 100 parts by weight of an organopolysiloxane containing at least two silicon-bonded alkenyl groups in one molecule;
(B) 0.1 to 50 parts by weight of an organohydrogenpolysiloxane containing at least two silicon-bonded hydrogen atoms in one molecule;
(C) 0 to 3000 parts by weight of thermally conductive particles and / or electrically conductive particles,
(D) 0.0001 to 20 parts by weight of a fine particle catalyst having an average particle diameter of 0.01 to 500 μm composed of wax particles having a melting point of 40 to 230 ° C. containing 0.001% by weight or more of platinum-based catalyst as platinum metal atoms ,
Tona is,
The thermosetting silicone rubber composition having a melt viscosity of 10 Pa · s or less at a melting point of the wax used for the wax particles + 20 ° C. and the thermosetting silicone rubber composition is coated or adhered. Relates to an electronic component or an electronic device.

The thermosetting silicone rubber composition of the present invention has a long working life at room temperature and excellent storage stability, and is excellent in workability because it cures in a short time when heated above the melting point of the wax in the particulate catalyst. is there. In addition, the electronic component or electronic device of the present invention is characterized in that it is excellent in reliability because it is coated, adhered, etc. with the cured product of the curable silicone rubber composition.

Hereinafter, the thermosetting silicone rubber composition of the present invention will be described in detail. The (A) component organopolysiloxane is the main component of the composition and contains at least two silicon-bonded alkenyl groups in one molecule. Examples of the silicon atom-bonded alkenyl group in component (A) include a vinyl group, an allyl group, a butenyl group, a pentenyl group, a hexenyl group, and a heptenyl group, and a vinyl group is particularly preferable. Examples of the bonding position of the alkenyl group in the component (A) include a molecular chain terminal and / or a molecular chain side chain. Examples of silicon-bonded organic groups other than alkenyl groups in component (A) include alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl and heptyl groups; phenyl and tolyl groups Aryl groups such as xylyl group and naphthyl group; aralkyl groups such as benzyl group and phenethyl group; and halogenated alkyl groups such as chloromethyl group, 3-chloropropyl group, 3, 3, 3-trifluoropropyl group and the like. In particular, a methyl group and a phenyl group are preferable. Examples of the molecular structure of the component (A) include a straight chain, a partially branched straight chain, a ring, and a branched chain, and a straight chain is particularly preferable. (A) Although the viscosity of a component is not limited, It is preferable that the viscosity in 25 degreeC is in the range of 10-500000 centipoise, and it is especially preferable that it is in the range of 50-100000 centipoise. This is because if the viscosity of component (A) at 25 ° C. is less than 10 centipoise, the physical properties of the resulting silicone rubber will decrease, and if this exceeds 500,000 centipoise, the resulting composition will be handled. This is because workability is lowered.

Examples of the organopolysiloxane of the component (A) include, for example, a trimethylsiloxy group-capped dimethylsiloxane / methylvinylsiloxane copolymer, a molecular chain both-ends trimethylsiloxy group-capped methylvinylpolysiloxane, and both molecular chains. Terminal trimethylsiloxy group-blocked dimethylsiloxane / methylvinylsiloxane / methylphenylsiloxane copolymer, molecular chain both ends dimethylvinylsiloxy group-blocked dimethylpolysiloxane, molecular chain both ends dimethylvinylsiloxy group-blocked methylvinylpolysiloxane, molecular chain both ends Dimethylvinylsiloxy-blocked dimethylsiloxane / methylvinylsiloxane copolymer, dimethylvinylsiloxy-blocked dimethylsiloxane / methylvinylsiloxane / methylphenylsiloxane copolymer , Wherein: the siloxane units of the formula R ¹ ₃ SiO _1/2: siloxane units represented by the formula R ^{1 ₂} R ₂ SiO _1/2: units represented by R ¹ ₂ SiO _2/2 and a small amount of the formula : An organopolysiloxane copolymer comprising a siloxane unit represented by SiO _4/2 , a siloxane unit represented by the formula: R ¹ ₂ R ² SiO _1/2 and a siloxane unit represented by the formula: R ¹ ₂ SiO _2/2 And a small amount of an organopolysiloxane copolymer composed of a siloxane unit represented by SiO _4/2 , a siloxane unit represented by a formula: R ¹ R ² SiO _2/2 and a small amount of formula: R ¹ SiO _3/2 Examples thereof include an organopolysiloxane copolymer comprising a siloxane unit represented by the formula: R ² SiO _3/2 and a mixture of two or more of these organopolysiloxanes. In the above formula, R ¹ is a monovalent hydrocarbon group other than an alkenyl group, for example, an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group; a phenyl group, a tolyl group Aryl groups such as a group, xylyl group and naphthyl group; aralkyl groups such as benzyl group and phenethyl group; and halogenated alkyl groups such as chloromethyl group, 3-chloropropyl group, 3, 3, 3-trifluoropropyl group and the like. It is done. In the above formula, R ² is an alkenyl group, and examples thereof include a vinyl group, an allyl group, a butenyl group, a pentenyl group, a hexenyl group, and a heptenyl group.

The organohydrogenpolysiloxane of component (B) is a crosslinking agent of the present composition and contains at least two silicon-bonded hydrogen atoms in one molecule. Examples of the bonding position of silicon atom-bonded hydrogen atoms in component (B) include molecular chain terminals and / or molecular chain side chains. Examples of the silicon atom-bonded organic group in component (B) include alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, and heptyl groups; phenyl, tolyl, xylyl, Aryl groups such as naphthyl group; aralkyl groups such as benzyl group and phenethyl group; halogenated alkyl groups such as chloromethyl group, 3-chloropropyl group, 3,3,3-trifluoropropyl group, etc. And a phenyl group are preferred. Examples of the molecular structure of the component (B) include linear, partially branched linear, cyclic, and branched, with linear being particularly preferred. Although the viscosity of (B) component is not limited, It is preferable that the viscosity in 25 degreeC is in the range of 1-500000 centipoise, and it is further more preferable in the range of 5-100,000 centipoise. This is because if the viscosity of the component (B) at 25 ° C. is less than 1 centipoise, the physical properties of the resulting silicone rubber will deteriorate, and if this exceeds 500,000 centipoise, the resulting composition will be handled. This is because workability is lowered.

Examples of such an organopolysiloxane of component (B) include, for example, molecular chain both ends trimethylsiloxy group-blocked methylhydrogen polysiloxane, molecular chain both ends trimethylsiloxy group-blocked dimethylsiloxane / methylhydrogensiloxane copolymer, molecule Trimethylsiloxy group-capped dimethylsiloxane / methylhydrogensiloxane / methylphenylsiloxane copolymer, both chain ends dimethylhydrogensiloxy group-capped dimethylpolysiloxane, molecular chain both ends dimethylhydrogensiloxy group-capped dimethylsiloxane / methyl Phenylsiloxane copolymer, dimethylhydrogensiloxy group-blocked methylphenylpolysiloxane with molecular chain at both ends, siloxane unit represented by formula: R ¹ ₃ SiO _1/2 and formula: R ¹ ₂ HSiO _{1 An} organopolysiloxane copolymer comprising a siloxane unit represented by _{/ 2} and a siloxane unit represented by the formula: SiO _4/2 , a siloxane unit represented by the formula: R ¹ ₂ HSiO _1/2 and a formula: SiO _4/2 An organopolysiloxane copolymer comprising the indicated siloxane units, a siloxane unit represented by the formula: R ¹ HSiO _2/2 and a siloxane unit represented by the formula: R ¹ SiO _3/2 or a formula: HSiO _3/2 Examples thereof include organopolysiloxane copolymers composed of siloxane units, and mixtures of two or more of these organopolysiloxanes. In the above formula, R ¹ is a monovalent hydrocarbon group other than an alkenyl group, for example, an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group; a phenyl group, a tolyl group Aryl groups such as a group, xylyl group and naphthyl group; aralkyl groups such as benzyl group and phenethyl group; and halogenated alkyl groups such as chloromethyl group, 3-chloropropyl group, 3, 3, 3-trifluoropropyl group and the like. It is done.

(B) The compounding quantity of a component exists in the range of 0.1-50 weight part with respect to 100 weight part of (A) component. This is because when the component (B) is less than 0.1 part by weight relative to 100 parts by weight of the component (A), the resulting composition does not sufficiently cure, and when this exceeds 50 parts by weight. This is because the resulting composition does not cure sufficiently, or the physical properties of the resulting silicone rubber change over time.

The thermally conductive particles and / or electrically conductive particles of component (C) are components added when high thermal conductivity is imparted to the silicone rubber obtained by curing the present composition. As these particles, known inorganic or metal particles (powder) can be used. Specifically, silica, alumina, aluminum nitride, silicon nitride, boron nitride, silicon carbide, calcium carbonate, zinc carbonate, zinc oxide, Inorganic powders such as magnesium oxide, titanium oxide, iron oxide, aluminum hydroxide, magnesium hydroxide, carbon black, diamond, platinum, gold, silver, copper, palladium, indium, aluminum, nickel, tin, lead, zinc, bismuth Examples thereof include metal powders such as iron and cobalt, mixtures thereof and alloy powders. Even if the main body of the particles is organic, at least a part of the surface may be coated with an inorganic or metallic heat conductive material or conductive material.

The particle diameter of the component (C) is not limited, but the average particle diameter is preferably 50 μm or less, and particularly preferably 0.1 μm to 30 μm. Two or more kinds of particles or particles having different average particle diameters may be used in combination. Examples of the shape of the component (C) include a spherical shape, a true spherical shape, a flake shape, a needle shape, and an indeterminate shape. Moreover, since the storage stability of the curable silicone rubber composition of the present invention is excellent, the component (C) may be surface-treated with an organosilicon compound or a known surface treating agent. Examples of the organosilicon compound include methyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, Alkoxysilanes such as 3-aminopropyltriethoxysilane and N- (2-aminoethyl) -3-aminopropyltrimethoxysilane; chlorosilanes such as methyltrichlorosilane, dimethyldichlorosilane and trimethylmonochlorosilane; hexamethyldisilazane; Silazanes such as hexamethylcyclotrisilazane; molecular chain both ends silanol-blocked dimethylsiloxane oligomer, molecular chain both ends silanol-blocked dimethylsiloxane / methylvinylsiloxane copolymer oligomer Both molecular chain terminals blocked with silanol groups methylvinylsiloxane oligomer and the siloxane oligomer such as both molecular chain terminals blocked with silanol groups methylphenylsiloxane oligomer. Examples of other surface treatment agents include organic metal compounds, organic metal complexes, fluorine-based organic compounds, organic compounds having a hydroxyl group, a carboxy group, and an amino group. As the surface treatment method, for example, a method of directly mixing heat conductive particles and / or electrically conductive particles and these surface treatment agents (dry treatment method), these surface treatment agents are treated with toluene, methanol, heptane. A method of treating by mixing with heat conductive particles and / or electrically conductive particles together with an organic solvent such as (wet treatment method), heat conductive particles in a mixture of component (A) and these surface treatment agents and / or Alternatively, the electrically conductive particles are blended, or these surface treatment agents are blended in the mixture of the component (A) with the thermally conductive particles and / or the electrically conductive particles, and the thermally conductive particles and / or the electrically conductive particles. And a method of treating the surface of the conductive particles (in-situ treatment method). In addition, when performing surface treatment of thermally conductive particles and / or electrically conductive particles with these surface treatment agents, for example, an organic metal compound such as organic titanium, water, or the like is added to improve the treatment efficiency. It is preferable to do.

(C) The compounding quantity of a component exists in the range of 0-3000 weight part with respect to 100 weight part of (A) component. Component (C) is a component for imparting thermal conductivity and / or electrical conductivity to the curable silicone rubber composition of the present invention, and unless it is necessary to obtain thermal conductivity and / or electrical conductivity. Although it is not necessary to use, if the amount of component (C) exceeds 3000 parts by weight with respect to 100 parts by weight of component (A), the viscosity of the resulting composition is remarkably increased, and the handling workability thereof is remarkably lowered. .

The fine particle catalyst of the component (D) is a catalyst for accelerating the curing of the composition, and is composed of wax particles having a melting point of 40 to 230 ° C. containing 0.001% by weight or more of a platinum-based catalyst as a platinum metal atom, The average particle diameter is 0.01-500 micrometers, Preferably it exists in the range of 0.1-50 micrometers. This is because it is difficult to produce a fine particle catalyst having an average particle diameter of less than 0.01 μm, and a fine particle catalyst having an average particle diameter exceeding 500 μm is difficult to uniformly disperse in component (A), and the resulting composition This is because the curability of the resin becomes uneven. The wax used for the wax particles has a melting point higher than room temperature, that is, a melting point of 40 ° C. or higher and 230 ° C. or lower, desirably 40 ° C. or higher and 150 ° C. or lower, particularly 60 to 100 ° C. It is essential to melt. Elution and diffusion of the platinum-based catalyst component in the thermal curing at a low temperature does not proceed smoothly and cannot be sufficiently cured in a short time if it is a simple thermoplastic having only a softening point and no melting point. At a temperature above the melting point, it is desirable to liquefy before the viscosity (melt viscosity) can be measured with a viscometer, and it is particularly desirable that the melt viscosity at a temperature of melting point + 20 ° C. is 10 Pa · s or less.

Although it is desirable that this wax does not dissolve in the liquid epoxy-containing polymer and / or epoxy-containing oligomer at 25 ° C., it does not have to be completely insoluble and may be substantially insoluble. In order to impart excellent adhesive properties to the thermosetting silicone rubber composition, a polymer component having a so-called epoxy group such as a glycidoxypropyl group and / or an oligomer component having an epoxy group are added. If the liquid epoxy-containing component has the property of dissolving the wax in the platinum-based catalyst-containing wax particles, the platinum-based catalyst component will elute into the thermosetting silicone rubber composition over the course of the storage period, resulting in stable storage. This is because there is a risk of remarkably reducing the performance. These epoxy-containing polymers and epoxy-containing oligomers are not particularly limited as long as they are liquid at room temperature. Epoxy resins, partial hydrolysates of epoxy-functional organoalkoxysilanes, cohydrolysates, partial cohydrolysates, epoxy modified Examples thereof include silicone and silicone-modified epoxy resin.

The wax used for component (D) is not limited as long as it has the above-mentioned properties, and includes plant waxes, animal waxes, petroleum waxes, synthetic waxes, etc., but alkylmethylpolysiloxane waxes are particularly desirable. . In order for this wax to have a clear melting point, it is desirable that the alkyl group has 3 or more carbon atoms, and in particular, long-chain alkyl groups having 6 or more carbon atoms, such as alkylmethyl polyalkyls such as lauryl groups and stearyl groups. Desirably, it is siloxane. The terminal blocking group of alkylmethyl polysiloxane is not limited, and examples thereof include a methyl group and an alkyl group.
Examples of the structure of component (D) include a structure in which a platinum-based catalyst is dissolved or dispersed in wax particles, and a microcapsule structure in which a platinum-based catalyst is included in a wax shell. Examples of this platinum-based catalyst include platinum fine powder, platinum black, platinum-supported silica fine powder, platinum-supported activated carbon, chloroplatinic acid, platinum tetrachloride, an alcohol solution of chloroplatinic acid, a complex of platinum and olefin, A complex of platinum and an alkenylsiloxane such as divinyltetramethyldisiloxane may be mentioned, and a divinyldisiloxane complex of platinum is particularly preferable. The content of the platinum-based catalyst in the component (D) is such an amount that the platinum metal atom is 0.001% by weight or more. This is because a fine particle catalyst composed of wax particles having a platinum-based catalyst content of less than 0.001% by weight as platinum metal atoms does not exhibit sufficient curing acceleration.

(D) As a method for preparing the component, for example, a platinum-based catalyst component and a wax having a melting point are mixed and heated to a melting point or higher while being dissolved, mixed, cooled to room temperature, and then a massive platinum-based catalyst-containing wax is added. It can be easily obtained by mechanically pulverizing with a pulverizer or the like. The powdery platinum-based catalyst-containing wax particles produced in this way are water, hydrocarbons, alcohols, ketones, in the range not dissolving the wax component in order to sufficiently remove the platinum-based catalyst component adhering to the surface. You may wash | clean with volatile solvents, such as low molecular weight siloxane.

(D) The compounding quantity of a component exists in the range of 0.0001-20 weight part with respect to 100 weight part of (A) component. This is because if the component (D) is less than 0.0001 parts by weight relative to 100 parts by weight of the component (A), the curability of the resulting composition is significantly reduced, and this is 20 parts by weight. Even if it exceeds, curability does not change so much and becomes uneconomical. The platinum-based metal content in the thermosetting silicone rubber composition is preferably 0.1 to 5000 ppm, and particularly preferably 0.5 to 100 ppm. This is because if the platinum-based metal atom content in the thermosetting silicone rubber composition is less than 0.1 ppm, sufficient curability cannot be obtained, and if it exceeds 5000 ppm, it is wasted.
The thermosetting silicone rubber composition of the present invention can be used in combination with a platinum-based catalyst other than the component (D) in order to supplement curability at low temperatures. Examples of such platinum catalysts include solid platinum catalysts such as platinum powder, platinum black, and platinum-supported silica fine powder, alcohol solutions such as chloroplatinic acid and platinum tetrachloride, and platinum and olefins or low-viscosity alkenyls. A liquid platinum-based catalyst such as a complex composed of siloxane is exemplified, but a liquid which dissolves in the thermosetting silicone rubber composition and becomes uniform is desirable, and in particular, a complex composed of platinum and a low-viscosity alkenylsiloxane is desirable. .

The curable silicone rubber composition of the present invention is prepared by uniformly mixing the above components (A) to (D). As other optional components in this composition, for example, fumed silica, precipitated silica, carbon black, quartz powder, glass fiber, and inorganic fillers such as organoalkoxysilane, organochlorosilane, and organosilazane are used. An inorganic filler formed by surface treatment with a silicon compound is exemplified. Moreover, in order to further improve the handling workability of the present composition at room temperature, it is preferable to incorporate a curing inhibitor. Examples of the curing inhibitor include alkyne alcohols such as 3-methyl-1-butyn-3-ol, 3,5-dimethyl-1-hexyn-3-ol, and 2-phenyl-3-butyn-2-ol. Enyne compounds such as 3-methyl-3-penten-1-yne and 3,5-dimethyl-3-hexen-1-yne; 1,3,5,7-tetramethyl-1,3,5,7- Examples include tetravinylcyclotetrasiloxane, 1,3,5,7-tetramethyl-1,3,5,7-tetrahexenylcyclotetrasiloxane, and benzotriazole. These curing inhibitors are preferably in the range of 10 to 50,000 ppm by weight in the present invention. In addition, the composition contains an organopolysiloxane containing one silicon atom-bonded hydrogen atom or alkenyl group in one molecule and a silicon atom-bonded hydrogen atom or alkenyl group within a range not impairing the object of the present invention. Organopolysiloxanes that contain silicon-bonded hydrogen atoms or alkenyl groups and silicon-bonded alkoxy groups in one molecule, organosilicon compounds that contain silicon-bonded alkoxy groups and epoxy groups in one molecule, Organosilicon compounds containing silicon-bonded hydrogen atoms or alkenyl groups, silicon-bonded alkoxy groups and epoxy groups in the molecule, organosilicon compounds containing silicon-bonded alkoxy groups and methacryloxy groups in one molecule, and adhesion promoter , Creep hardening inhibitor, storage stabilizer, heat-resistant Agents, antioxidants, flame retardants, coloring agents.

The method for preparing the heat conductive silicone rubber composition of the present invention is not particularly limited, and for example, the heat conductive silicone rubber composition can be prepared using a mixing apparatus such as a loss mixer or a planetary mixer. When preparing the thermally conductive silicone rubber composition of the present invention, particularly when the component (D) is blended, it is necessary to mix at a temperature below the melting point of the wax in the component (D) so that it does not break. There is. The heat conductive silicone rubber composition thus prepared can be stored refrigerated (for example, 10 ° C. or lower) or at room temperature (10-30 ° C.), but is preferably refrigerated.

The application method of the thermosetting silicone rubber composition of the present invention is not limited, and may be dispense application, print application, spray application, brush application or the like. Further, the thermosetting silicone rubber composition of the present invention can take various states such as liquid, paste, and clay at room temperature. When the thermosetting silicone rubber composition is held at a temperature equal to or higher than the melting point of the wax in the component (D), the wax is melted and rapidly cured by the action of the platinum-based catalyst. For example, when the wax has a melting point of 80 ° C., when heated to 80 ° C. or higher, preferably 100 ° C. or higher, it rapidly cures to form silicone rubber. Silicone rubber has various hardness from gel to rubber that is strong and difficult to deform. When thermal conductivity is required after curing, the thermal conductivity after curing is desirably 1 W / m · K or more. In the case of a thermosetting silicone rubber composition that requires electrical conductivity, the volume resistivity after curing is desirably 1 × 10 ⁰ Ω · cm or less, and 1 is required when semiconductivity is required. is preferably in the range of ^{× 10 0 Ω · cm~1 × 10} 10 Ω · cm, it is desirable if the electrical insulation is required is 1 × ^{10 10} Ω · cm or more. In addition, the content of the volatile low molecular weight siloxane component contained in the thermosetting silicone rubber composition of the present invention is not limited, but the content is included so as not to contaminate electronic components and electronic devices and their surroundings by volatile components and bleed components. A lower rate is desirable. For example, the volatile content when heated at 100 ° C. for 1 hour in a hot air circulating oven is preferably 1% by weight or less, and more preferably 0.1% by weight or less.

The electronic component and the electronic device of the present invention include a capacitor, a resistor, a diode, a memory, a computing element (CPU) and the like. The thermosetting silicone rubber composition of the present invention, particularly the thermally conductive filler and / or the electrically conductive filler. It is characterized by being coated or adhered with a thermosetting silicone rubber composition containing

[Method of measuring initial viscosity and viscosity after 120 hours of thermosetting silicone rubber composition]
Using a rotary viscometer (TV-20) manufactured by Toki Sangyo Co., Ltd., the viscosity (unit: Pa · s) was measured at a rotor rotation speed of 4 rpm and a temperature of 25 ° C. to obtain an initial viscosity. Thereafter, it was stored at a temperature of 25 ° C., and the viscosity was measured by the same method after 120 hours.

[Method for Measuring Solubility of Platinum-Based Catalyst-Containing Wax Particles in Co-hydrolyzate (Viscosity 30 mPa · s) of 3-Glycidoxypropyltrimethoxysilane and Methyltrimethoxylane]
After mixing platinum catalyst-containing wax particles, 3-glycidoxypropyltrimethoxysilane and methyltrimethoxylane co-hydrolyzate (viscosity 30 mPa · s) at a weight ratio of 1: 100, the mixture is put in a transparent container. The dispersion state of the platinum-based catalyst-containing wax particles was photographed. The container was allowed to stand at 25 ° C. for 20 hours, and then the state of dispersion of the platinum-based catalyst-containing wax particles was similarly photographed. The two photographs were compared visually, and when the platinum-based catalyst-containing wax particles were dissolved and the amount thereof was reduced, it was determined that the platinum-based catalyst-containing wax particles showed solubility.

[Method for Measuring Curability of Thermosetting Silicone Rubber Composition at 80 ° C.]
A thermosetting silicone rubber composition is applied to a 10 mm square silicon wafer in a thickness of 1 mm, placed in a hot air circulation oven at 80 ° C., and until the liquid thermosetting silicone rubber composition is cured by finger observation. Time was measured.

[Method of measuring thermal conductivity of thermosetting silicone rubber composition]
A thermosetting silicone rubber composition was applied between 10 mm square silicon wafers to a thickness of 40 μm or 80 μm, and cured by heating for 1 hour in a hot air circulation oven at 80 ° C. to obtain a test specimen. The thermal resistance (unit: ° C / W) at each thickness is measured, the relationship between each thickness (unit: m) and thermal resistance is plotted on a graph, a straight line is drawn, and the slope is determined as thermal conductivity (unit: W / mK).

[Method of measuring volume resistivity of thermosetting silicone rubber composition]
Using a metal mask having a thickness of 10 mm and an opening having a length of 50 mm and a thickness of 100 μm, the thermosetting silicone rubber composition was printed and applied onto an electrically insulating FR-4 glass epoxy resin substrate, It was cured by heating for 1 hour in a hot air circulation oven to obtain a test specimen. Resistance was measured by applying a voltage of 10 volts between 50 mm long measurement ends, and volume resistivity (unit: Ω · cm) was calculated.

[Reference Example 1] [Preparation of platinum particles containing platinum catalyst of the present invention]
Dissolve 1.3 g of chloroplatinic acid hexahydrate in 3 g of isopropyl alcohol, 100 g of alkylmethylsiloxane wax powder having a melting point of 70 ° C. (AMS-C30 manufactured by Dow Corning, melt viscosity 0.1 Pa · s at 90 ° C.) At the same time, it was put into a three-necked separable flask equipped with stirring blades, stirred while flowing a small amount of nitrogen gas, heated to 90 ° C. and completely dissolved. After confirming that the isopropyl alcohol did not flow out from the solvent outlet condenser attached to the upper part of the flask, stirring was stopped and the mixture was cooled to room temperature by natural cooling. Next, the chloroplatinic acid-containing wax in the flask was taken out while scraping, and crushed in a mortar to be fluted. The frosting was carried out at 300 mesh pass and 400 mesh on to obtain chloroplatinic acid-containing wax particles having an average particle diameter of 40 μm, a melting point of 70 ° C. and a platinum content of 0.5% by weight.
Visual observation of the solubility of the chloroplatinic acid-containing wax particles in the co-hydrolyzate (viscosity 30 mPa · s) of 3-glycidoxypropyltrimethoxysilane and methyltrimethoxylane did not dissolve at 25 ° C. It was.

[Reference Example 2] [Preparation of Comparative Example of Platinum-Based Catalyst-Containing Silicone Resin Particles]
Dissolve 1.3 g of chloroplatinic acid hexahydrate in 3 g of isopropyl alcohol and have a softening point of 85 ° C. as a main component, a siloxane unit represented by the formula: C ₆ H ₅ SiO _3/2 , and other formulas: Siloxane unit represented by (C ₆ H ₅ ) ₂ SiO _2/2 , siloxane unit represented by formula: (CH ₃ ) ₂ SiO _2/2 , represented by formula: CH ₃ (CH ₂ ═CH) SiO _2/2 Together with 100 g of a siloxane unit and a thermoplastic silicone resin containing a siloxane unit represented by the formula: CH ₃ (C ₆ H ₅ ) SiO _2/2 (melt viscosity at 105 ° C. exceeds 10 Pa · s) The mixture was put into a 300 cc loss mixer equipped with stirring blades, and the temperature was raised to 105 ° C. with stirring while flowing a small amount of nitrogen gas. After confirming that the isopropyl alcohol did not flow out from the exhaust pipe at the top of the mixer, stirring was stopped and the mixture was cooled to room temperature by natural cooling. Next, the chloroplatinic acid-containing silicone resin particles in the mixer were taken out while being scraped, and pulverized by pulverization in a mortar. A chloroplatinic acid-containing silicone resin particle having a mesh size of 300 mesh pass and 400 mesh on, an average particle size of 40 μm, a softening point of 85 ° C. and a platinum content of 0.5% by weight was obtained.
The solubility of the chloroplatinic acid-containing silicone resin particles in the co-hydrolyzate (viscosity 30 mPa · s) of 3-glycidoxypropyltrimethoxysilane and methyltrimethoxylane was visually observed. Was confirmed.

[Example 1]
100 parts by weight of dimethylpolysiloxane blocked with a dimethylvinylsiloxy group at both ends of a molecular chain having a viscosity of 100 mPa · s at 25 ° C. and an average of 3 silicon-bonded hydrogen atoms in the side chain of the molecular chain having a viscosity of 5 mPa · s at 25 ° C. 5 parts by weight of a trimethylsiloxy group-blocked dimethylsiloxane / methylhydrogensiloxane copolymer having both ends of a molecular chain having a molecular weight of 400 parts by weight of spherical alumina fine powder having an average particle diameter of 9 μm and a specific gravity of 3.9, and an average particle diameter of 20 μm 200 parts by weight of spherical alumina fine powder having a specific gravity of 3.9, 1.0 part by weight of the platinum-based catalyst-containing wax particles prepared in Reference Example 1, and 1,3,5,7-tetramethyl- 1,3,5,7-tetravinylcyclotetrasiloxane 0.5 parts by weight, 3-glycidoxypropyltrimethoxysilane and methyltri A thermosetting silicone rubber composition was prepared by uniformly mixing 1.0 part by weight of a co-hydrolyzed product of methoxylane (viscosity 30 mPa · s) in a loss mixer.
The initial viscosity, the viscosity after 120 hours, the curability at 80 ° C., the thermal conductivity after curing, and the volume resistivity of this composition were measured and summarized in Table 1.

[Comparative Example 1]
In Example 1, instead of the preparation of the platinum-based catalyst-containing wax particles prepared in Reference Example 1, an isopropyl alcohol solution of platinum-containing catalyst (platinum containing 1.3 g of chloroplatinic acid hexahydrate dissolved in 100 g of isopropyl alcohol). A thermosetting silicone rubber composition was prepared in the same manner except that 0.5% by weight was used.
The initial viscosity, the viscosity after 120 hours, the curability at 80 ° C., the thermal conductivity after curing, and the volume resistivity of this composition were measured and summarized in Table 1.

[Comparative Example 2]
A thermosetting silicone rubber composition was prepared in the same manner as in Example 1 except that the chloroplatinic acid-containing silicone resin particles prepared in Reference Example 2 were used instead of the platinum-based catalyst-containing wax particles prepared in Reference Example 1. A product was prepared.
The initial viscosity, the viscosity after 120 hours, the 80 ° C. curability and thermal conductivity, and the volume resistivity of this composition were measured and summarized in Table 1.

[Example 2]
200 parts by weight of dimethylpolysiloxane blocked with a dimethylvinylsiloxy group at both ends of a molecular chain having a viscosity at 25 ° C. of 100 mPa · s, and an average of three silicon-bonded hydrogen atoms in the side chain of the molecular chain at 25 ° C. having a viscosity of 5 mPa · s 5 parts by weight of a trimethylsiloxy group-blocked dimethyl / methylhydrogensiloxane copolymer having both ends of a molecular chain having a molecular weight of 400 parts by weight of spherical atomized silver powder having an average particle diameter of 3 μm and a specific gravity of 10.5, and an average particle diameter of 400 parts by weight of flake silver powder on a scale having a specific gravity of 10.5, 8 μm, 0.8 parts by weight of the platinum-based catalyst-containing wax particles prepared in Reference Example 1, 1.3 g of chloroplatinic acid hexahydrate 0.2 parts by weight of an isopropyl alcohol solution of platinum-containing catalyst (platinum content: 0.5% by weight) dissolved in 100 g of isopropyl alcohol, and 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane 0.5 part by weight, co-hydrolyzate of 3-glycidoxypropyltrimethoxysilane and methyltrimethoxylane (Viscosity 30 mPa · s) was uniformly mixed in a loss mixer to prepare a thermosetting silicone rubber composition.
The initial viscosity, the viscosity after 120 hours, the curability at 80 ° C., the thermal conductivity after curing, and the volume resistivity of this composition were measured and summarized in Table 1.

[Comparative Example 3]
In Example 2, a thermosetting silicone rubber composition was prepared in the same manner except that the chloroplatinic acid-containing silicone resin particles prepared in Reference Example 2 were used instead of the platinum-based catalyst-containing wax particles prepared in Reference Example 1. Prepared.
The initial viscosity, the viscosity after 120 hours, the 80 ° C. curability and thermal conductivity, and the volume resistivity of this composition were measured and summarized in Table 1.

The thermosetting silicone rubber composition of the present invention is blended with a platinum-based catalyst-containing fine particle catalyst that does not melt at room temperature but easily melts by heating at a low temperature. It has excellent workability and is useful as a coating agent or adhesive that cures at a low temperature in a short time when heated. In addition, electronic components or electronic devices such as capacitors, resistors, diodes, memories, and arithmetic elements (CPUs) with low heat resistance coated or bonded at low temperature with the thermosetting silicone rubber composition of the present invention are highly reliable and useful. is there.

Claims (3)

(A) 100 parts by weight of an organopolysiloxane containing at least two silicon atom-bonded alkenyl groups in one molecule, (B) an organohydrogenpolysiloxane containing at least two silicon atom-bonded hydrogen atoms in one molecule 0.1 to 50 parts by weight, (C) heat conductive particles and / or electrically conductive particles 0 to 3000 parts by weight, and (D) a platinum-based catalyst containing 0.001% by weight or more as a platinum metal atom particulate catalyst from 0.0001 to 20 parts by weight of the average particle diameter 0.01~500μm consisting wax particles is 40 to 230 ° C., Ri Tona,
A thermosetting silicone rubber composition, wherein the wax has a melt viscosity of 10 Pa · s or less at a melting point + 20 ° C. of the wax used for the wax particles . 2. The thermosetting silicone rubber composition according to claim 1, wherein the wax is an alkylmethylpolysiloxane wax. An electronic component or electronic device coated or bonded with the thermosetting silicone rubber composition according to claim 1 or 2 .