JPH0826225B2 - Heat-curable silicone elastomer composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to a heat-curable silicone elastomer composition which is cured by a hydrosilylation reaction. More specifically, the present invention relates to a heat-curable silicone elastomer composition that has excellent storage stability around room temperature and excellent curability at high temperatures and that is cured by a hydrosilylation reaction. More specifically, it has excellent storage stability by isolating the hydrosilylation reaction catalyst contained in the composition from other reactive components at room temperature,
And, the heat resistance and transparency of the silicone elastomer in which the components necessary for the separation of the catalyst are cured are not impaired.
The present invention relates to a heat-curable silicone elastomer composition.

[Prior Art and Its Problems] A heat-curable silicone elastomer composition that is cured by a hydrosilylation reaction has a feature that it rapidly proceeds to a deep layer portion without generating a reaction by-product. It is used in a wide range of fields such as adhesives, potting materials, and coating materials.

However, this type of heat-curable silicone elastomer composition has extremely poor storage stability and has a drawback that it is difficult to store the composition in a single container, and therefore, the components constituting the composition are usually used. There is a problem in that each of them must be stored in a separate container.

Heretofore, various methods for solving this problem have been proposed. The first method is a method using an additive having an action of suppressing the catalytic activity of the hydrosilylation reaction catalyst, for example, benzotriazole, acetylene compound, hydroperoxy compound and the like. However, these methods have drawbacks such that the curing characteristics are deteriorated when a long-term storage stability is attempted, and the curing time is prolonged.

The second method is to isolate the hydrosilylation reaction catalyst from other reactive components in the composition until heat curing.

For example, JP-B-53-41707 and JP-A-58-37053 have proposed a method in which a mixture of a hydrosilylation reaction catalyst and a silicone resin having a softening point is ground and then added to and mixed with a reaction system. These methods were effective for relatively low activity catalysts such as chloroplatinic acid 2-ethylhexanol solution and isopropanol-modified chloroplatinic acid, but when a highly active catalyst is used, there is almost no effect of suppressing the activity of the catalyst. There was a problem. Furthermore, since these proposals produced particles by pulverization, it was difficult to make the average particle diameter 10 μm or less. Therefore, there is a problem that the catalyst is not sufficiently diffused from the fine particles during the heat curing reaction and the curing reaction of the silicone elastomer is not completed.

Methods for solving this problem have been proposed in JP-A-64-45468, JP-A-64-47442 and JP-A-64-51140. The contents can be arranged in two. First, a solution consisting of a hydrosilylation reaction catalyst, a thermoplastic resin having a softening point, and a solvent compatible with them is emulsified with an aqueous surfactant solution, and the solvent is dried and removed from the emulsion to recover fine particles. That was the (in-liquid drying method). The second is a method of removing the catalyst remaining on the surface of the fine particles and in the vicinity of the surface by washing the fine particles containing the hydrosilylation reaction catalyst with a solvent which dissolves the hydrosilylation reaction catalyst but does not dissolve in the resin. By the first method, the average particle size is 10μ
Fine particles of m or less can be produced, which allows the crosslinking reaction of the silicone elastomer to be completed. The second method has made it possible to impart sufficient storage stability even with a highly active hydrosilylation reaction catalyst. These proposals have made it technically possible to keep the reaction system in an unreacted state until a certain period of time, in particular, to store a silicone elastomer that is cured by a hydrosilylation reaction for a long period of time after blending all components. However, since these methods take a lot of time and effort to produce the target fine particles, there remains a problem that they are economically difficult to carry out industrially. Another problem is that the fine particles produced by such a method have a strong aggregation and it is difficult to uniformly disperse them in the reaction system. Further, since a resin having heat resistance lower than that of the silicone polymer is used as the thermosetting resin, there is a problem that mechanical properties are deteriorated or discolored when the cured silicone elastomer is used at high temperature.

As a method for improving this, the present inventors previously disclosed in JP-A-2-4833 that after producing fine particles composed of a silicone resin having a softening point and a hydrosilylation reaction catalyst, the hydrosilylation reaction catalyst is dissolved but the silicone resin Proposed a method of washing fine particles with an insoluble solvent. By this method, it is possible to produce a heat-curable silicone elastomer composition which has sufficiently high storage stability and rapid curing characteristics at high temperature, and which does not lower the heat resistance of the cured silicone elastomer. I can do it now. However, there remains a big problem in the production of fine particles before washing with a solvent. The first method for producing the fine particles exemplified in JP-A-2-4833 is to emulsify a solution of a hydrosilylation reaction catalyst, a silicone resin having a softening point and a solvent compatible with them with an aqueous surfactant solution, It was a method of collecting fine particles after the solvent was dried and removed from the emulsion. The second method was a method of pulverizing a mixture of a hydrosilylation reaction catalyst and a silicone resin having a softening point. In the first method, it takes time to manufacture fine particles,
It was economically very disadvantageous to carry out industrially. The second method has a problem that it is difficult to completely cure the silicone elastomer composition because it is not possible to produce fine particles having an average particle diameter of 10 μm or less.

In JP-A-2-9448, a heat-curable silicone elastomer having long-term storage stability at room temperature and unexpectedly high curing rate at a high temperature by using a hydrosilylation reaction catalyst-containing silicone resin in combination with a hydrosilylation reaction-inhibiting compound It was proposed that a composition be obtained. By using this method and the method of JP-A-2-4833 together, a very rapid curing at a high temperature becomes possible. However, this method also has the same problems in the production of granular materials as described in JP-A-2-4833.

There has been another common problem in making the hydrosilylation reaction catalyst fine particles proposed so far. The resin to be microparticulated had to be selected from materials that did not dissolve in the base polymer of the silicone elastomer composition. For example, in the case of a silicone elastomer composition using dimethylpolysiloxane as a base polymer, it was necessary to use a silicone resin containing a phenyl group. However, for this reason, when fine particles composed of a silicone resin and a hydrosilylation reaction catalyst are added, there is a problem that the composition becomes cloudy and the transparency, which is one of the characteristics of the silicone elastomer, is impaired. In studying to solve the problem of the decrease in transparency, the present inventors have found that the surfactant, which is an essential component when producing fine particles by a liquid drying method, impairs the transparency of the silicone elastomer composition. It was found to be one of the causes. After producing the fine particles in the liquid, even if the fine particles are washed many times, a certain amount of the surfactant may remain on the surface of the fine particles, and further, the smaller the particle diameter, the larger the residual amount of the surfactant may be. I also checked. Then, it was confirmed that this residual surfactant not only impairs the transparency of the silicone elastomer composition but also impairs the heat resistance after curing, that is, causes mechanical properties to deteriorate and discolor.

[Problems to be Solved by the Invention] The present inventors have arrived at the present invention as a result of extensive studies to solve the above problems. The object of the present invention is excellent in economy, has a sufficiently long storage stability at room temperature, has a rapid curing rate at high temperature and complete curability, and does not impair the heat resistance of conventional silicone elastomers, and is transparent. It is intended to provide a heat-curable silicone elastomer composition having excellent properties.

[Means for Solving the Problem and Its Action] The present invention provides (a) an organopolysiloxane having at least two alkenyl groups in one molecule, (b) at least two silicon atom-bonded hydrogen atoms in one molecule. And (c) a hydrosilylation reaction catalyst and a silicone resin having a softening point or a glass transition point of 40 to 200 ° C., which has an average particle diameter of 0.01 to 10 μm. (D) a hydrosilylation reaction-inhibiting compound, which is within the range, the content of particles having a particle size of more than 10 μm is 5% by weight or less, and which contains substantially no surfactant. And a heat-curable silicone elastomer composition.

The organopolysiloxane of the component (a) used in the present invention is a main component of the composition of the present invention and is required to have at least two silicon-bonded alkenyl groups in one molecule. Examples of the alkenyl group include a vinyl group, an allyl group and a hexenyl group. Examples of the organic group other than the alkenyl group bonded to the silicon atom of the organopolysiloxane include a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, an alkyl group such as an octyl group, and an aryl group such as a phenyl group, 3 It is a monovalent hydrocarbon group exemplified by a substituted hydrocarbon group such as a 3,3,3-trifluoropropyl group, and the number of organic groups bonded to a silicon atom is preferably 1.0 to 2.3 on average. The organopolysiloxane is generally linear, but may have a branched siloxane skeleton. The degree of polymerization is not particularly limited, but usually the viscosity at 25 ° C is 10 to
Those in the range of 1,000,000 centipoise are used.

The organohydrogenpolysiloxane of the component (b) used in the present invention is a cross-linking agent for the organopolysiloxane of the component (a). In order for the composition of the present invention to form a network structure, at least one molecule should be used. It is necessary to have two silicon-bonded hydrogen atoms. As the organic group bonded to the silicon atom in addition to the hydrogen atom, the above-mentioned (a)
Examples thereof are the same as the component organopolysiloxane. Only one type of organic group may be used in one molecule, or two or more types may be mixed. The molecular structure of the organohydrogenpolysiloxane may include a linear structure, a network structure, or a three-dimensional structure, and a homopolymer or copolymer thereof or a mixture of two or more polymers can also be used. . The degree of polymerization of this organohydrogenpolysiloxane is usually such that the viscosity at 25 ° C is 0.5 to 50,
The range is 000 centipoise, preferably 1 to 10,000
Those within the range of centipoise are used.

The blending amount is such that the molar ratio of silicon atom-bonded hydrogen atoms in this component to silicon atom-bonded alkenyl groups in component (a) is preferably in the range of 0.5 / 1 to 10/1. Usually, it is in the range of 0.1 to 10 parts by weight with respect to 100 parts by weight of the component (A).

The granular material composed of the hydrosilylation reaction catalyst of the component (c) and the silicone resin is a catalyst for crosslinking the silicon atom-bonded alkenyl group of the component (a) and the silicon atom-bonded hydrogen atom of the component (b) by a hydrosilylation reaction. Is. All conventionally known catalysts exhibiting hydrosilylation catalytic activity can be used. Specifically, chloroplatinic acid, alcohol-modified chloroplatinic acid, platinum-olefin complex, platinum-ketone complex, platinum-vinylsiloxane complex, alumina, silica, platinum supported on carbon black,
Examples include platinum catalysts such as platinum black, palladium catalysts such as tetrakis (triphenylphosphine) palladium, and complex catalysts such as rhodium, nickel and cobalt catalysts. Among these, a platinum catalyst is preferable from the viewpoint of high activity, and a platinum-vinylsiloxane complex catalyst is particularly preferable from the viewpoint of compatibility with the components (a) and (b).

The silicone resin used as the component (c) needs to have a softening point or glass transition point of 40 to 200 ° C. This softening point is the temperature at which the resin begins to flow due to its own weight or its surface tension, and can be easily known by observing the crushed particles with a microscope while raising the temperature at a constant rate. The glass transition point can be known by measuring with a DSC (differential scanning calorimeter). In the present invention, if either the softening point or the glass transition point is in the range of 40 to 200 ° C, it can be used. When the softening point or the glass transition point is lower than 40 ° C, the storage stability of the composition is significantly lowered, and when it is higher than 200 ° C, a sufficient heat curing rate cannot be obtained. The composition of the silicone resin is not particularly limited, and any resin having a siloxane skeleton as a main component can be used, but a monophenyl siloxane unit (PhSiO _3/2 ) as a main component,
In addition, diphenylsiloxane unit (Ph ₂ SiO), dimethylsiloxane unit (Me ₂ SiO), methylsiloxane unit (Me
Resins containing SiO _3/2 ), methylvinylsiloxane units (MeViSiO), etc. are common. Among them, it is preferable to use a silicone resin containing an alkenyl group such as a vinyl group from the viewpoint of improving storage stability and transparency of the composition of the present invention.

The component (c) is fine particles composed of such a hydrosilylation reaction catalyst and a silicone resin having a softening point or a glass transition point of 40 to 200 ° C., and its size has an average particle diameter of 0.
It is necessary to be 01 to 10 μm. Average particle size is 10μ
If it is larger than m, the curing will be incomplete even if the composition is heated, and the heat resistance and the like of the silicone elastomer composition will be impaired. On the other hand, if the average particle size is smaller than 0.01 μm, it becomes difficult to obtain sufficient storage stability of the composition. The particle size distribution can be measured by the centrifugal sedimentation method or the laser scattering method, but the weight% of particles having a size of more than 10 μm measured by these methods should not exceed 5%. If it exceeds 5%, the physical properties and transparency of the cured silicone elastomer composition will deteriorate. Further, it is desirable that the shape of such fine particles is spherical in view of dispersibility in the composition and curing stability.

Further, the component (c) should not substantially contain a surfactant. If a surfactant is included,
This is because the heat resistance and transparency of the silicone elastomer composition produced by crosslinking the components (a) and (b) are impaired.
There are many production methods in which a surfactant is an essential component when producing a fine particle having an average particle size of 0.01 to 10 μm, which is composed of a hydrosilylation reaction platinum catalyst and a silicone resin, but such a surfactant is not used. It is desirable to avoid it in the present invention. Most of the surfactant used during manufacture can be removed by post-washing, but it is not possible to achieve complete cleaning. Particularly, in the fine particles as in the present invention, the amount of the remaining surfactant is large, and the heat resistance and transparency of the composition are impaired because the heat resistance of such residual surfactant is lower than that of polysiloxane. Most desirable is to produce a granulate that meets the above conditions without the use of any surfactant.

It consists of a silicone resin with a softening point or glass transition point of 40 to 200 ° C and a hydrosilylation reaction catalyst.
Granules of 0.01 to 10 μm can be produced by a gas phase drying method without using any surfactant. That is, it is a method in which a mixture of a solvent compatible with both the hydrosilylation reaction catalyst and the silicone resin is sprayed in a hot air stream and dried and solidified in a sprayed state. The average particle size produced by this method is in the range of 0.01-10 μm, and the particle size is 10 μm.
Granules having a content of particles exceeding m of 5% by weight or less are very preferable in that the heat resistance of the composition of the present invention is not impaired at all and the transparency of the silicone elastomer can be maintained. Further, the time and labor required for the production are remarkably reduced as compared with the in-liquid drying method, and the production can be economically advantageous. In addition, the vapor phase drying method is preferable because it is easy to uniformly add and mix the silicone elastomer composition.

The ratio of the hydrosilylation reaction catalyst to the silicone resin is preferably such that the content of the hydrosilylation reaction catalyst in the component (c) is 100 ppm or more as a metal atom. If this is less than 100 ppm, the ratio of the silicone resin in the composition of the present invention becomes too high,
This is because the physical properties after curing may be impaired. The compounding amount of the component (c) is usually 0.01 to 1000 pp as metal atom with respect to the organopolysiloxane of the component (a).
It is within the range of m, preferably within the range of 0.1 to 100 ppm. The blending amount of the component (c) itself is determined by the content ratio of the hydrosilylation reaction catalyst in the component (c) and the amount of the hydrosilylation reaction catalyst added to the component (a), and generally (a) ) For 100 parts by weight of ingredient
It will be 0.005 to 10 parts by weight. In order to obtain a highly transparent silicone elastomer composition, the addition amount of the component (c) is as small as possible, and is 0.1 part by weight or less based on 100 parts by weight of the organopolysiloxane of the component (a). desirable.

The component (d) is an essential component for promoting curing and achieving complete curing when the composition of the present invention is heated and cured. This is a compound that has a catalytic inhibitory effect on the hydrosilylation reaction catalyst, and all compounds that have been conventionally known to have a curing delaying effect and a storage stability improving effect in a silicone elastomer composition that cures by a hydrosilylation reaction are used. can do.
Examples of such compounds include phosphorus-containing compounds such as triphenylphosphine, nitrogen-containing compounds such as tributylamine and tetramethylethylenediamine and benzotriazole, sulfur-containing compounds, acetylene compounds, compounds containing two or more alkenyl groups, and hydro Examples include peroxy compounds and maleic acid derivatives. Among these, compounds containing an alkenyl group or an alkynyl group are desirable. In particular, a compound containing two or more alkynyl groups in a molecule, a compound containing an alkenyl group and an alkynyl group in a molecule, a compound containing an alkenyl group and an alcoholic hydroxyl group in a molecule, and silicon adjacent to each other through an oxygen atom. Organosilicon compounds having a bond unit in which an alkenyl group is bonded to both atoms, maleic acid diester, and the like are particularly desirable.

The degree of the effect promoting effect of the component (d) greatly differs depending on the chemical structure of the component (d). Therefore, the addition amount of the component (d) should be adjusted to the optimum amount for each of the component (d) to be used, but generally, if the addition amount is too small, the effect promoting effect cannot be obtained. If it is too much, the effect is rather impaired, so the content is preferably in the range of 0.1 to 50,000 ppm with respect to the component (a).

The composition of the present invention is a silicone elastomer composition comprising the above-mentioned components (a) to (d). If necessary, finely powdered silica such as fumed silica or wet silica, or surface-hydrophobicized may be used. Finely divided silica, crepe hardening inhibitors, polymers other than silicone, organic solvents, iron oxides, heat-resistant agents such as rare earth compounds, manganese carbonate, flame retardants such as fumed titanium oxide, diatomaceous earth, carbonic acid Blending of calcium, glass fiber, carbon black, etc. may be carried out without impairing the object of the present invention.

The composition of the present invention can be easily obtained by uniformly mixing the components (a) to (d). The mixing order is not particularly limited, but the component (c) is mixed with a small amount of the component (a) and uniformly dispersed, and then added to the mixture of (a), (b) and (d). Method is preferred. In this case, any means may be used as long as it does not destroy the granulated catalyst for hydrosilylation reaction of the component (c). Further, the temperature condition differs depending on the component (c) to be used and therefore cannot be unconditionally specified, but it is desirable that the temperature is at least the softening point or glass transition temperature of the silicone resin used for the component (c).

The composition of the present invention as described above has excellent storage stability near room temperature, and thus can be stored for a long period of time as a one-component thermosetting silicone elastomer composition.
Moreover, it is possible to quickly and completely cure by heating. Further, since it does not contain a surfactant whose heat resistance is inferior to that of the silicone polymer, even if the cured silicone elastomer is used at high temperature, mechanical properties are not deteriorated or discolored, and a highly transparent elastomer. Can be

[Examples] Next, the present invention will be described with reference to Reference Examples, Examples, and Comparative Examples.

Reference Example 1 Preparation of platinum vinyl siloxane complex composition 6 g of chloroplatinic acid aqueous solution (platinum content 33%) and 16 g of 1,3
-Divinyltetramethyldisiloxane was dissolved in 35 g of isopropyl alcohol. 10 g of sodium bicarbonate was added to this solution, and the mixture was reacted at 70 to 80 ° C. for 30 minutes while stirring in a suspended state. Isopropyl alcohol and water at a pressure of 50 mmHg,
A 1,3-divinyltetramethyldisiloxane solution of a platinum complex-catalyzed platinum complex catalyst having a platinum content of 8.5 wt% was prepared by devolatization under a condition of a temperature of 45 ° C. and filtering the solid content.

Reference Example 2 Preparation of thermoplastic silicone resin 1 332 g of phenyltrichlorosilane, 53 g of dimethyldichlorosilane and 110 g of diphenyldichlorosilane were added.
The solution diluted with 150 g of toluene is mixed with 430 g of toluene and 14
Hydrolysis was carried out dropwise into a liquid composed of 2 g of methyl ethyl ketone and 114 g of water. The reaction mixture was washed with water to remove hydrogen chloride, then the organic phase was separated and further heated to remove methyl ethyl ketone. Next, 0.2 g of potassium hydroxide was added thereto, and the mixture was heated. The generated water was distilled off, and the mixture was neutralized with acetic acid and washed with water repeatedly. Thereafter, the solvent was evaporated to obtain a thermoplastic silicone resin. This thermoplastic silicone resin had a glass transition point of 65 ° C and a softening point of 85 ° C.

Reference Example 3 Preparation of Thermoplastic Silicone Resin 2 The glass transition point was the same as in Reference Example 2 except that the compound of the toluene solution of chlorosilanes was changed to 459 g of phenyltrichlorosilane, 31 g of dimethyldichlorosilane and 150 g of toluene. A thermoplastic silicone resin having a temperature of 95 ° C and a softening point of 140 ° C was obtained.

Reference Example 4 Preparation of Thermoplastic Silicone Resin 3 Glass transition in the same manner as in Reference Example 2 except that the compound of the toluene solution of chlorosilanes was changed to 459 g of phenyltrichlorosilane, 34 g of methylvinyldichlorosilane, and 150 g of toluene. A thermoplastic silicone resin having a point of 90 ° C and a softening point of 140 ° C was obtained.

Reference Example 5 Preparation of Platinum Catalyst-Containing Fine Particles 1 In a glass container equipped with a stirrer, 900 g of the thermoplastic silicone resin obtained in Reference Example 2, 500 g of toluene, and dichloromethane were added.
4600 g was charged and mixed uniformly. Next, 44.4 g of the platinum vinyl siloxane complex composition obtained in Reference Example 1 was added,
By mixing, a homogeneous solution of the platinum vinyl siloxane complex composition and the thermoplastic silicone resin was obtained. Next, this solution was continuously sprayed using a two-fluid nozzle into a spray dryer tank (manufactured by Ashizawa Nitro Atomizer Co., Ltd.) in which a nitrogen gas was made to flow in a hot air flow. Here, the hot airflow temperature of nitrogen gas was 95 ° C. at the inlet of the spray dryer and 45 ° C. at the outlet of the spray dryer, and the hot airflow velocity was 1.3 m ³ / min. After the operation for 1 hour, 450 g of platinum-vinylsiloxane complex composition-containing silicone resin fine particles were collected by a back filter. The average particle diameter of the fine particles was 1.1 μm, and the content of the fine particles of 5 μm or more was 0.5% by weight. The platinum content was 0.40% by weight. When the shape of the fine particles was observed with a scanning electron microscope, it was confirmed that the fine particles were spherical.

Reference Example 6 Preparation of Platinum Catalyst-Containing Fine Particles 2 In the same manner as in Reference Example 5, except that 900 g of the thermoplastic silicone resin obtained in Reference Example 3 was used in place of the thermoplastic silicone resin obtained in Reference Example 2, 425 g of platinum-vinylsiloxane complex composition-containing silicone resin fine particles were collected in 1 hour. The average particle diameter of the fine particles was 1.0 μm, and the content of the fine particles of 5 μm or more was 0.5% by weight. The platinum content was 0.39% by weight. It was confirmed by a scanning electron microscope that the fine particles were spherical.

Reference Example 7 Preparation of Platinum Catalyst-Containing Fine Particles 3 In the same manner as in Reference Example 5, except that 900 g of the thermoplastic silicone resin obtained in Reference Example 4 was used in place of the thermoplastic silicone resin obtained in Reference Example 2. 460 g of platinum vinyl siloxane complex composition-containing silicone resin fine particles were collected in 1 hour. The average particle diameter of the fine particles was 1.1 μm, and the content of the fine particles of 5 μm or more was 0.5% by weight. The platinum content was 0.40% by weight. It was confirmed by a scanning electron microscope that the fine particles were spherical.

Reference Example 8 Preparation of Platinum Catalyst-Containing Fine Particles 4 The amount of the thermoplastic silicone resin obtained in Reference Example 2 was changed to 90 g, and the amount of the platinum-vinylsiloxane complex composition obtained in Reference Example 1 was changed to 4.44 g. In the same manner as in Reference Example 28, 28 g of platinum-vinylsiloxane complex composition-containing silicone resin fine particles were collected in 1 hour. The average particle size of the fine particles was 0.6 μm, and the content of the fine particles of 5 μm or more was 0.1% by weight. The platinum content was 0.40% by weight. It was confirmed by a traveling electron microscope that the fine particles were spherical.

Example 1 A base composition was prepared by thoroughly mixing 1000 g of α, ω-divinyldimethylpolysiloxane (viscosity 1500 cs at 25 ° C.) and 200 g of fumed silica whose surface was hydrophobized with hexamethyldisilazane at room temperature. did. Each of the platinum catalyst-containing fine particles obtained in Reference Examples 5 to 8 and this base composition
After mixing 90 g at room temperature, a platinum catalyst-containing silicone composition was obtained by passing through three rolls once. It was confirmed that the platinum catalyst-containing fine particles were uniformly dispersed through the 200-mesh filter with almost no residue.

To 120 g of the base composition, 2.8 g of siloxane having an average molecular formula of Me ₃ SiO (Me ₂ SiO) ₃ (MeHSiO) ₅ SiMe ₃ and 0.01 g of phenylputinol
Is added and mixed uniformly, and the platinum catalyst-containing silicone composition prepared above is added so that the platinum content in the composition is 5 ppm and mixed at room temperature to obtain a heat-curable silicone elastomer. A composition was obtained.
The heat curing characteristics of these compositions were measured at a temperature shown in Table 1 with a Curastometer Model 3 (manufactured by Toyo Baldwin Co., Ltd.). Here, the heat-curing property was determined by the curing start time (It) and the time until the torque reached 90% of the maximum (T ₉₀ ). Also, the composition was stored at 25 ° C. for 1 year, and then the thermosetting property was measured again. Further, in order to quantify the storage stability, these compositions were stored under an atmosphere of 50 ° C. and the number of days until the viscosity became twice the initial value was examined. These measurement results were as shown in Table 1. From these measurement results, the heat-curable organopolysiloxane composition of the present invention can be stored at room temperature for a long period of time,
It was confirmed that curing was completed in a few minutes at high temperature. Furthermore, a remarkably high storage stability was confirmed when using platinum catalyst-containing fine particles of a thermoplastic silicone resin containing a vinyl group.

Comparative Example 1 A solution was prepared by mixing 40 g of the platinum vinyl siloxane complex composition obtained in Reference Example 1, 320 g of the thermoplastic silicone resin obtained in Reference Example 2 and 6600 g of dichloromethane. An emulsion was prepared by adding this solution to an aqueous solution containing 15 g of polyvinyl alcohol and applying high shear. Dichloromethane was gradually volatilized while flowing nitrogen gas at room temperature for 48 hours, and then solid particles were obtained by centrifugation. Wash it twice with water,
Further, after washing twice with methanol and twice with hexamethyldisiloxane, it was dried at 40 ° C. for 2 days to obtain 305 g of fine particles. The average particle diameter of the fine particles was 1.0 μm, and the content of the fine particles of 5 μm or more was 0.5% by weight. The platinum content was 0.38% by weight. When the fine particles were observed with a traveling electron microscope, it was confirmed that the fine particles were spherical. The time required to produce these fine particles was substantially 4 days in total from the preparation of the emulsion to the end of drying.

Using the platinum catalyst-containing fine particles, a platinum catalyst-containing silicone composition was prepared in the same amount as in Example 1. Unlike that shown in Example 1, it was necessary to pass three rolls eight times in order to uniformly mix with a 200 mesh filter until almost all the residue was gone. Using this platinum catalyst-containing silicone composition, a heat-curable silicone elastomer composition was prepared in the same manner as in Example 1, and the evaluation results were as follows.

Immediately after preparation It 30.2 seconds T ₉₀ 36.7 seconds After 1 year It 28.7 seconds T ₉₀ 34.5 seconds Compared with Example 1, it was confirmed that the time from the preparation of the fine particles to the preparation of the platinum catalyst-containing composition and the number of steps were significantly increased. Was done.

Example 2 100 parts of organopolysiloxane raw rubber consisting of 99.8 mol% of dimethylsiloxane unit and 0.2 mol% of methylvinylsiloxane unit (polymerization degree: 5000), 8.0 parts of dimethylsiloxane blocked with silanol groups at both ends (viscosity 60 cs at 25 ° C.) and specific surface area 40 parts of 200 m ² / g fumed silica was put into a kneader mixer and kneaded under heating until uniform. To 100 parts of this rubber base, 0.40 parts of siloxane having an average molecular formula of Me ₃ SiO (Me ₂ SiO) ₃ (MeHSiO) ₅ SiMe ₃ and 0.001 part of 1-ethynyl-1-cyclohexanol are mixed, A heat-curable organopolysiloxane composition was prepared by adding and mixing the four platinum catalyst-containing silicone compositions obtained in Example 1 so that the platinum atom content was 0.85 ppm. For comparison, the platinum catalyst-containing silicone composition obtained in Comparative Example 1 was used to prepare a composition in the same manner. Further, for comparison, a composition was prepared in the same manner except that the platinum vinyl siloxane complex composition obtained in Reference Example 1 was used instead of the platinum catalyst-containing silicone composition. 170 ° C for these compositions
It was cured under pressure for 10 minutes to obtain a 2 mm thick sheet. JIS
The mechanical properties of these sheets were measured by the method according to K6301. Measure visible absorption spectrum, wavelength 600nm
The transparency was evaluated by measuring the transmittance at.
In addition, changes in appearance were observed by aging at 180 ° C for 1 month. Further, each composition before curing was stored at room temperature for 3 months, and then a sheet was prepared in the same manner as in the initial stage to measure mechanical properties. Table 2 shows the results.

Example 3 A thermosetting silicone elastomer composition was prepared in the same manner as in Example 1 except that the following compound was used instead of phenylbutynol, and the curability was measured immediately after the preparation and after storage for 3 months at room temperature. evaluated. The results are shown below.

Methylbutynol (added amount: 0.1 g) Immediately after preparation: It = 28.3 seconds T ₉₀ = 33.5 seconds After 3 months: It = 28.1 seconds T ₉₀ = 32.0 seconds 3,5 Dimethyl-1-hexyn-3-ol (added amount) : 0.01
g) Immediately after preparation: It = 27.6 seconds T ₉₀ = 32.0 seconds After 3 months: It = 28.0 seconds T ₉₀ = 33.2 seconds 1,3,5,7-tetravinyltetramethyltetracyclosiloxane (addition amount: 0.1g) Preparation Immediately after: It = 30.5 seconds T ₉₀ = 35.0 seconds After 3 months: It = 31.2 seconds T ₉₀ = 35.7 seconds t-butyl hydroperoxide (addition amount: 0.01 g) Immediately after preparation: It = 35.8 seconds T ₉₀ = 40.7 seconds 3 After 3 months: It = 37.1 seconds T ₉₀ = 45.2 seconds Diethyl maleate (amount added: 0.01 g) Immediately after preparation: It = 28.3 seconds T ₉₀ = 34.1 seconds After 3 months: It = 29.4 seconds T ₉₀ = 34.9 seconds Methyltris (methylbutynoxy) ) Silane (amount added: 0.0
001g) Immediately after preparation: It = 31.2 seconds T ₉₀ = 36.0 seconds After 3 months: It = 33.4 seconds T ₉₀ = 37.4 seconds Tetramethylethylenediamine (amount added: 0.0005g) Immediately after preparation: It = 40.3 seconds T ₉₀ = 47.2 seconds 3 After 3 months: It = 44.2 seconds T ₉₀ = 50.0 seconds Benzotriazole (addition amount: 0.01g) Immediately after preparation: It = 35.2 seconds T ₉₀ = 50.1 seconds After 3 months: It = 38.1 seconds T ₉₀ = 54.3 seconds Triphenylphosphine ( Addition amount: 0.0005 g) Immediately after preparation: It = 41.5 seconds T ₉₀ = 56.1 seconds After 3 months: It = 44.4 seconds T ₉₀ = 59.8 seconds [Effect of the invention] The heat-curable silicone elastomer composition of the present invention is (a) )-(D) components, especially (c) component and (d) component, so they are economically efficient, have sufficiently long storage stability at room temperature, and have a rapid curing rate at high temperature. It has curability, does not impair the heat resistance of conventional silicone elastomers, and has excellent transparency.

Claims (8)

[Claims] 1. An organopolysiloxane having (a) at least two alkenyl groups in one molecule, (b) an organohydrogenpolysiloxane having at least two silicon-bonded hydrogen atoms in one molecule, (c) ) A particle comprising a hydrosilylation reaction catalyst and a silicone resin having a softening point or a glass transition point of 40 to 200 ° C., the particle having an average particle size of 0.01 to 10 μm and a particle size of more than 10 μm. A heat-curable silicone elastomer composition comprising: (d) a hydrosilylation reaction-inhibiting compound, which has a particle content of 5% by weight or less and contains substantially no surfactant. Stuff. 2. The heat-curable silicone elastomer composition according to claim 1, wherein the component (c) is a spherical granular material. 3. The heat-curable silicone elastomer composition according to claim 1, wherein the component (c) is a granular material produced without using a surfactant. 4. A component (c) comprising a silicone resin having a softening point or a glass transition point of 40 to 200 ° C., a hydrosilylation reaction catalyst, and a solvent compatible with both of them is sprayed in a hot air stream to obtain a sprayed state. The heat-curable silicone elastomer composition according to claim 1, which is obtained by drying and solidifying with. 5. The heat-curable silicone elastomer composition according to claim 1, wherein the component (d) is a hydrosilylation reaction-inhibiting compound having an alkenyl group or an alkynyl group. 6. The heat-curable silicone elastomer composition according to claim 1, wherein the hydrosilylation reaction catalyst is a platinum catalyst. 7. The heat-curable silicone elastomer composition according to claim 1, wherein the platinum catalyst is a platinum alkenyl siloxane catalyst. 8. The heat-curable silicone elastomer composition according to claim 1, wherein the silicone resin contains an alkenyl group.