JP2002309087A - Composition for heat resistant silicone rubber and silicon rubber using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the composition for a heat resistant silicone rubber capable of being resistant to a continuous use at >=300 deg.C, especially in applications at high temperatures under pressure-added conditions and provide a heat resistant silicone rubber by using the same. SOLUTION: This composition for a heat resistant silicone rubber comprises 100 mass wt. of an organopolysiloxane having the average unit formula: Ra SiO(4-a)/2 (wherein R expresses a substituted or nonsubstituted monovalent hydrocarbon group; a=1.95-2.05), 5-100 mass wt. of (B) a silica-based filler, 0.01-5 mass wt. of (C) a curing agent, 0.1-5 mass wt. of (D) iron oxide red and 0.1-5 mass wt. of (E) glass.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a silicone rubber having excellent heat resistance and a composition for a silicone rubber as a raw material thereof, and more particularly, to a silicone having a heat resistance capable of withstanding continuous use at 300 ° C. or more. The present invention relates to a polyorganosiloxane composition capable of providing a rubber and a heat-resistant silicone rubber produced using the composition.

[0002]

2. Description of the Related Art When natural rubber exceeds 100.degree. C. and general organic rubber exceeds 150.degree. C., it deteriorates in a short time and cannot be used. It can be used continuously even at high temperatures and is known as a rubber with excellent heat resistance.

In order to further improve the heat resistance of silicone rubber, a method of adding iron oxide (US Pat. No. 335278)
No. 1), a method of adding an oxide and a hydroxide of a lanthanum-based rare earth metal (Japanese Patent Publication No. 36-6189), a method of adding allyl urethane (Japanese Patent Publication No. 38-16677), and a method of adding polyethylpyridine (Japanese Patent Publication No. 49-150
No. 47). However, none of them can withstand long-time use at a high temperature of 300 ° C., and the heat deterioration is remarkable.

Japanese Patent Application Laid-Open No. H11-106559 discloses a silicone rubber that can withstand long-term use at 300 ° C. is a polyorganosiloxane containing a catalytic amount of a platinum-based catalyst, a large amount of redwood, and an organosilicon compound having an epoxy group. Organosiloxane compositions have been proposed. Also,
In JP-B-63-52060, a composition for silicone rubber with improved heat resistance, polyorganosiloxane,
Polyorganosiloxane compositions containing a large amount of ground or fused quartz and a large amount of red iron oxide are disclosed.

However, in these compositions, the addition of a silica-based filler, which is a reinforcing agent for silicone rubber, is considered to hinder the improvement of heat resistance.
The strength of the obtained silicone rubber is not sufficient, and it cannot be applied to applications under conditions where a compressive force is applied.

The present invention has been made in view of such circumstances, and an object of the present invention is to withstand continuous use at a temperature of 300 ° C. or more, particularly high temperature use under a pressure. And a heat-resistant silicone rubber using the same.

[0007]

The composition for heat-resistant silicone rubber of the present invention comprises: (A) an average unit formula of R _a SiO _{(4-a) / 2} (where R is a substituted or unsubstituted monovalent carbon); 100 parts by mass of an organopolysiloxane having a hydrogen group, a = 1.95 to 2.05) (B) Silica-based filler 5 to 100 parts by mass (C) Curing agent 0.01 to 5 parts by mass (D) Bengala 0 0.1 to 5 parts by mass (E) Glass 0.1 to 5 parts by mass.

[0008] The curing agent is preferably an organic peroxide. The glass has a diameter of 3 to 20 μm and a length of 50 to 150 μm, and a particle size of 10 to 300 μm.
And at least one selected from the group consisting of glass particles and glass powder of 150 mesh or less. The bengara preferably has a particle size of 0.02 to 50 μm.

The heat-resistant silicone rubber of the present invention is a silicone rubber obtained by vulcanizing the composition of the present invention,
The JIS-A hardness is 5 to 90.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The heat-resistant silicone rubber of the present invention is used.
The composition comprises (A) an average unit formula R_aSiO_{(4-a) / 2}(Where R
Is a substituted or unsubstituted monovalent hydrocarbon group, a = 1.95-
2.05), the organopolysiloxane (B)
Rica-based filler, (C) curing agent, (D) bengara, (E)
It contains glass.

The polyorganosiloxane used as the component (A) in the composition of the present invention has an average unit formula of R _a SiO
_{(4-a) / 2} . In the formula, R is an alkyl group having 1 to 10, preferably 1 to 8 carbon atoms such as a methyl group, an ethyl group, a propyl group and a butyl group; and 1 to 1 carbon atoms such as a vinyl group, an allyl group and a butenyl group. 10, preferably 1 to 8 alkenyl groups; aryl groups such as phenyl and tolyl;
Halogen-substituted carbon atoms such as chloromethyl, chloropropyl, and 3,3,3-trifluoropropyl in which some or all of the hydrogen atoms bonded to the carbon atoms of the alkyl, alkenyl, and aryl groups have been substituted with halogen atoms. Hydrogen group; 2- or 2-, wherein a part or all of hydrogen atoms bonded to carbon atoms of an alkyl group, an alkenyl group, and an aryl group are substituted with a cyano group.
A substituted or unsubstituted hydrocarbon group having 1 to 10 carbon atoms selected from a cyano-substituted hydrocarbon group such as a cyanoethyl group. In the formula, a is from 1.95 to 2.05. Specifically, it is mainly composed of a linear diorganosiloxane represented by the following chemical formula (1), and as long as a satisfies the above range, there is a branch as in the following chemical formula (2), As shown in the formula (3), the terminal may be cyclic with a siloxane bond.

[0012]

Embedded image

A preferred repeating unit is dimethylsiloxane in which at least 50%, more preferably at least 98% of R is a methyl group. The degree of polymerization n is 3000-10000
It is preferable that

The silica filler as the component (B) in the composition of the present invention is added for the purpose of reinforcing the silicone rubber, increasing the viscosity, improving the processability, and increasing the amount. In particular,
Fumed silica, wet silica, fumed silica whose surface is hydrophobized, wet silica, diatomaceous earth, and the like are used. The silica-based filler has a specific surface area of 1 m ² /
g or more, preferably 50 m ² / g or more is preferably used.

The content of the component (B) in the composition of the present invention is at least 5 parts by weight, preferably at least 25 parts by weight, based on 100 parts by weight of the polyorganosiloxane as the component (A). Not more than 75 parts by mass, preferably 75
Not more than parts by mass. If the amount is less than 5 parts by mass, the reinforcing effect is not sufficient, so that the strength of the obtained silicone rubber is weak, and the silicone rubber cannot withstand applications used under a compression load. If the amount exceeds 100 parts by mass, the obtained silicone rubber becomes too hard and lacks elasticity, and is not suitable for use as a rubber.

The curing agent as the component (C) is used for crosslinking and curing of the polyorganosiloxane, and specifically includes an organic peroxide, a metal fatty acid salt, a metal alcoholate, an amine compound, or an organohydrogensiloxane and platinum. Although a combination of a series compound is used, an organic peroxide is preferably used in order to obtain more excellent heat resistance.

As the organic peroxide, benzoyl peroxide, monochlorobenzoyl peroxide, p-
Methylbenzoyl peroxide, 2,4-dichlorobenzoyl peroxide, t-butyl perbenzoate, dicumyl peroxide, 2,5-bis- (t-butylperoxy) -2,5-dimethylhexane, 2,5
Dicarbonates such as -bis- (t-butylperoxy) -2,5-dimethylhexine, dimyristyl peroxycarbonate, dicyclododecylperoxydicarbonate, and t-butyl monoperoxycarbonate. , One or a combination of two or more of these.

The content of the component (C) in the composition of the present invention is in the range of 0.01 to 5 parts by mass based on 100 parts by mass of the polyorganopolysiloxane as the component (A). Is appropriately selected according to the hardness of the silicone rubber to be used.

Bengala as the component (D) is added in combination with glass as the component (E) to increase heat resistance.

The type of redwood used is not particularly limited, but the particle size is 0.02 to 50 μm and the specific surface area is 50 to 150 m
² / g is preferably used. As industrial bengara, CAPELLE C, a pigment for transparent blending,
Appoxyt Red 4435B, Transoxide Red (TOR) manufactured by Dainichi Seika, and the like are used.
The same effect can also be obtained by Ryuka Hanabe, manufactured by Mie Color Techno Co., Transoxide Yellow (TOY) manufactured by Dainichi Seika Co., Ltd., which has crystal water and is generally called iron yellow, and Biferrox manufactured by Bayer Corporation.

[0021] The content of red iron oxide in the composition of the present invention is 0.1 to 100 parts by mass of the polyorganosiloxane.
It is at least 1 part by mass, preferably at least 0.5 part by mass and at most 5 parts by mass, preferably at most 2 parts by mass. If the amount is less than 0.1 part by mass, the effect of improving heat resistance due to bengal is not sufficient, and if it exceeds 5 parts by mass, the change in hardness and elongation becomes too large, and the rubber cannot be used.

The glass as the component (E) is added together with the component (D) to improve the heat resistance of the silicone rubber. It is known that, as a component (D), red iron oxide has a function as a radical scavenger to suppress curing deterioration due to the progress of crosslinking of silicone rubber and a function to cut a polysiloxane main chain as a catalyst. on the other hand,
(E) Addition of only glass as a component does not have the effect of improving heat resistance. However, due to the synergistic action with red iron oxide having the above-mentioned effect, excellent heat resistance effect, specifically, even when used at a high temperature of 300 ° C., Curing deterioration and softening deterioration are suppressed, and rubber elasticity can be maintained for a long time.

The glass used for the component (E) may be one containing silicate as a main component.
Various glasses such as soda-lime glass, borosilicate glass, lead glass, aluminosilicate glass, and alkali glass can be used. The shape of the glass is also not particularly limited, and a glass fiber having a diameter of 3 to 20 μm and a length of 50 to 150 μm; a glass particle having a particle size of 10 to 300 μm; Glass powder is used. Specifically, colorless, brown, green, crushed cullet manufactured by Ino Glass Co., Ltd., EGP70M-01N manufactured by Unitika Glass Fiber Co., Ltd., MB-10, J120, GB731 manufactured by Toshiba Barotini can be used.

The glass content of the composition is 0.1 parts by mass or more, preferably 0.5 parts by mass or more, and 5 parts by mass or less, preferably 2 parts by mass or less, based on 100 parts by mass of the polyorganosiloxane. is there. If the amount is less than 0.1 part by mass, the effect of improving heat resistance by combined use with bengara is not recognized. If the amount is more than 5 parts by mass, a change in hardness and elongation with respect to standing at a high temperature is increased because a synergistic effect with bengala is offset. Because.

The heat-resistant silicone rubber composition of the present invention comprises:
In addition to the above components (A) to (E), a low molecular weight organosilicon compound such as dimethylsiloxane, diphenylsilanediol, or alkoxysilane having a hydroxyl group at a terminal may be added as necessary.

The silicone rubber of the present invention is obtained by vulcanizing and molding the silicone rubber of the present invention having the above composition.
The IS-A hardness is 5 to 90, preferably 20 to 80. If the JIS-A hardness is less than 5, the strength is too small to withstand the load, and if it exceeds 90, the rubber elasticity becomes small, and it becomes harder due to use at high temperature, so that it cannot be used as rubber.

Although the production method is not particularly limited, generally, first, the above components (A) and (B) are uniformly mixed with a two-roll mill or a kneader mixer, and then mixed at 100-400.
After a heat treatment of several seconds to several hours at ° C., a base compound is obtained. (C)-(E)
After blending the components, the mixture is uniformly kneaded using two rolls or the like, placed in a mold and vulcanized. The vulcanization molding conditions may be appropriately set according to the composition of the composition to be used and the hardness of the silicone rubber to be obtained. Specifically, 160-1
After press vulcanization molding at 70 ° C, 2 to 2 at about 200 ° C
Secondary vulcanization for 4 hours.

The silicone rubber of the present invention is formed to have a JIS-A hardness of about 5 to 90. The hardness may be appropriately selected depending on the application, and the specific composition of the composition of the present invention and the vulcanization conditions may be appropriately selected according to the hardness of the silicone rubber finally obtained. For example, when used in a compressed state like a sealing material, the JIS-A hardness is preferably 20 to 80 from the viewpoint of the balance between strength and rubber elasticity.

The silicone rubber of the present invention has a small change in hardness and can maintain rubber elasticity even when continuously used at 300 ° C. due to the synergistic action of bengara and glass. In particular, when kept at a high temperature of 300 ° C. in a compressed state, the surface of the conventional silicone rubber was hardened due to severe curing, but the silicone rubber of the present invention hardened the surface and maintained the rubber elasticity. it can.
Therefore, the heat-resistant silicone rubber of the present invention can be suitably used as a sealing material for members used at high temperatures.

[0030]

[Example] [Measurement and evaluation method of heat resistance]
Hardness before and after standing at 00 ° C for 24 hours or 72 hours,
The changes in tensile strength and elongation were examined by the following evaluation methods.

Hardness (degree) JIS-K6253 before and after conducting a heat resistance test
JIS-A hardness was measured according to the above, and the change (difference) in hardness before and after the test was determined.

Tensile strength Before and after the heat resistance test, the tensile strength (MP
a) was measured according to JIS-K6253. Also,
The rate of change (%) in tensile strength by the test was determined.

Elongation (%) Before and after performing the heat resistance test, the elongation (%)
It was measured according to JIS-K6253. Further, the rate of change (%) of elongation by the test was determined.

[Blending composition and heat resistance] 99.775 mol% of dimethylsiloxane unit, 0.2 mol% of methylvinylsiloxane unit, 0.02 mol% of dimethylvinylsiloxane unit
5 parts by weight of 100 parts by weight of a gum-like polyorganosiloxane having an average degree of polymerization of 5000, 3 parts by weight of diphenylsilanediol and 5 parts by weight of dimethyldimethoxysilane as a dispersant, and 40 parts by weight of fumed silica as a reinforcing agent (Japan) 20 parts by mass of Nipsil VN3LP manufactured by Silica Co., Ltd. and 20 parts by mass of Aerosil 200 manufactured by Nippon Aerosil Co., Ltd. were mixed and uniformly kneaded, and then heat-treated at 150 ° C. for 4 hours to prepare a base compound.

In the base compound, 2, 2
5-dimethyl 2,5-di (t-butylperoxy) hexane (RC-4 manufactured by Toray D. Corning Silicone Co., Ltd.)
(50P)), and bengara (CAPELLE Ca)
ppoxyt Red 4435B: particle size 0.1-0.
02 μm), glass fiber (EGP70M-01N manufactured by Unitika Glass Fiber Co., Ltd .: diameter 9 μm, average fiber length 70)
μm) and cerium oxide (Cerium oxide FN, manufactured by Daiichi Kagaku Kagaku Kogyo Co., Ltd.) in the amounts shown in Table 1, and uniformly kneaded with two rolls, followed by press vulcanization at 175 ° C. for 10 minutes. Further, secondary vulcanization was performed at 200 ° C. for 4 hours to obtain a silicone rubber sheet No. having hardness, elongation and tensile strength as shown in Table 1. 1-9 were obtained.

The obtained silicone rubber sheet no. 1 to
For No. 9, hardness, tensile strength and elongation were measured. Table 1
In the middle, it is indicated as “initial”. Furthermore, the hardness, tensile strength, and elongation after being left at 300 ° C. for 24 hours were measured to determine the change or rate of change before and after the heat test. Table 1 shows the results.

[0037]

[Table 1]

In the case of silicone rubber (No. 1) in which the base compound was merely cured with a curing agent, the crosslinking at a high temperature allowed the polyorganosiloxane to crosslink, and the rubber was turned into a resin. Decreased. When only Bengala was added (No. 2), it was softened by leaving it at a high temperature, and its tensile strength and elongation were reduced. In addition, when cerium oxide was added (No. 4), and when cerium oxide and glass fiber were added (No. 5), in both cases, they were softened by being left at a high temperature, and the tensile strength and elongation were reduced. . On the other hand, when only glass fiber was added (No.
3) When left at a high temperature, crosslinking progressed to form a resin, and the tensile strength and elongation decreased.

Silicone rubber No. containing both red iron and glass fiber Nos. 6 to 9 are Nos. The change in hardness was small and the change in tensile strength and elongation was also small as compared with 1 to 5. Therefore, it can be seen that both the glass and glass are necessary in order to ensure the heat resistance to withstand the use condition at 300 ° C.

No. With respect to the silicone rubber test pieces corresponding to 1, 2, 3, and 7, the decomposition start and end temperatures of the polymer were measured by thermal analysis. Table 2 shows the results.

[0041]

[Table 2]

From Table 2, when comparing the silicone rubber (No. 1) obtained by simply curing the base compound with a curing agent and the silicone rubber (No. 3) containing glass fibers, the difference in the decomposition behavior of the polymer is as follows. It was not recognized, and it was confirmed that the glass fiber alone had no heat resistance improving effect. On the other hand, in the case of silicone rubber (No. 2) to which bengara is added, the decomposition temperature of the polymer is No. 2; 30 compared to 1,3
It can be seen that the temperature was higher than about ° C, and it was difficult to decompose. However, no. Δt of No. 2 is No. Since it is smaller than 1,3, once the decomposition of the polymer starts,
It can be seen that the decomposition proceeds rapidly. On the other hand, when both glass fiber and red iron oxide are added (N
o. In 7), the decomposition start temperature is N
o. 2 and Δt is no. It is larger than 1, 3 and it can be seen that the decomposition progresses slowly even when the decomposition is started.

[Type of Glass and Heat Resistance] To the base compound prepared above, 2,5-dimethyl 2,5-di (t-butylperoxy) hexane (Toray Co., Ltd.) was used as a curing agent.
(Corning Silicone RC-4 (50P))
0.5 parts by mass were added, and then bengara (CAPELL) was added.
Capoxyt Red 4435B manufactured by E Company, glass fiber (EGP70M manufactured by Unitika Glass Fiber Co., Ltd.)
-01N: diameter 9 μm, fiber length 70 mm), glass beads (GB731: manufactured by Toshiba Barotini Co., particle size 30 μm),
Amorphous glass (Io Glass Co., cullet colorless, brown, green: 200 mesh or less) was added in the amount shown in Table 3,
After uniformly kneading with two rolls, press vulcanization was performed at 175 ° C. for 10 minutes, and secondary vulcanization was performed at 200 ° C. for 4 hours. 11-16 were obtained. The above glass fibers and glass beads correspond to E glass, and cullet corresponds to alkali glass.

The obtained silicone rubber sheet no. 11
The hardness, tensile strength, and elongation of each of the samples No. to No. 16 were measured, and the hardness, tensile strength, and elongation after standing at 300 ° C. for 24 hours were measured to determine the change or rate of change before and after the heat test. Table 3 shows the results.

[0045]

[Table 3]

No. containing both glass and red iron 12
No. to No. 16, the hardness change, the tensile strength change rate, and the elongation change rate before and after the heat resistance test were almost the same. From this, it is understood that the shape of the glass may be spherical, fibrous, or irregular in order to improve the heat resistance. Further, it is understood that the type of glass may be E glass or alkali glass. In addition, No. Since the hardness change rate, tensile strength change rate, and elongation change rate of 14 to 16 were almost the same, it is considered that there is no difference in the heat resistance effect by the coloring component.

[Type and heat resistance of bengalara] To the base compound prepared above, 2,5-dimethyl 2,5-di (t-butylperoxy) hexane (RC manufactured by Toray D. Corning Silicone Co., Ltd.) was used as a curing agent. -4 (50P))
After adding 0.5 parts by mass, 0.5 parts by mass of glass fiber (EGP70M-01N manufactured by Unitika Glass Fibers Co., Ltd.) and 0.5 parts by mass of bengara are added, and the mixture is uniformly kneaded with two rolls. Press vulcanization at 175 ° C. for 10 minutes, and secondary vulcanization at 200 ° C. for 4 hours. 21-25 were obtained.

As the bengala, Cappoxyt Red manufactured by CAPELLE, which is a bengara for transparent blending, is used.
4435B (average particle size: 0.1 to 0.02 μm) and TOR manufactured by Dainichi Seika (average particle size: 0.1 to 0.02 μm);
Rika 100 manufactured by Mie Color Techno Co., commonly called Iron Red
(Average particle size 0.5 μm) and Bayerox 915 manufactured by Bayer having water of crystallization and generally called iron yellow
(Average particle size: 0.5 μm).

The obtained silicone rubber sheet no. 21
About 25, hardness, tensile strength, and elongation were measured, and hardness, tensile strength, and elongation after standing at 300 ° C. for 72 hours were measured to determine the change or rate of change before and after the heat test. Table 4 shows the results.

[0050]

[Table 4]

From Table 4, it can be seen that The hardness change, the tensile strength change rate, and the elongation change rate were all the same in any of 22 to 25. It can be seen that each of the redwoods has an effect of imparting heat resistance.

[Types of Reinforcing Agent and Hardening Agent and Heat Resistance] In addition to the combination of the base compound and the hardening agent prepared above, a polymer base compound containing different types of reinforcing agents and curing specified by each manufacturer. As a combination of agents, SH871U manufactured by Toray D. Corning Silicone Co., Ltd. (reinforcing agent: diatomaceous earth, curing agent: 2,5-
Dimethyl 2,5- (t-butylperoxy) hexane), TSE2323-5U (reinforcing agent: fumed silica,
Curing agent: 2,5-dimethyl 2,5- (t-butylperoxy) hexane), TSE22 manufactured by GE Toshiba Silicone Co., Ltd.
77-U (reinforcing agent: fumed silica, curing agent: 2,5-dimethyl 2,5-di (t-butylperoxy) hexane), TSE221-7U (reinforcing agent: diatomaceous earth, curing agent: 2,5) -Dimethyl 2,5-di (t-butylperoxy) hexane). In each case, there was no additive, and there was a case where there was no additive, as well as Capella manufactured by CAPELLE.
xyt RED 4435B) and glass fiber (EGP70M-01N manufactured by Unitika Glass Fiber Co., Ltd.), kneaded uniformly with two rolls, press-vulcanized at 175 ° C. for 10 minutes, and further 200
After vulcanization at 4 ° C. for 4 hours, silicone rubber sheet no. 31-35 were obtained.

Regarding the prepared silicone rubber sheet,
The hardness, tensile strength and elongation were measured.
The hardness, tensile strength, and elongation after standing for a time were measured, and the rate of change before and after the heat test was determined. Table 5 shows the results.

[0054]

[Table 5]

No. In any of the cases 31 to 35, the degree of change in hardness was reduced by adding bengala and glass fiber, and it was found that the combined use of bengala and glass fiber improved heat resistance.

No. In the case of No. 35, the softening progressed somewhat due to the combination of the glass fiber and the bengara, probably because the hardening was small even without the additive. However, the tensile strength and elongation change are small,
It can be seen that the heat resistance of the silicone rubber has been improved.

[Heat resistance under compression conditions] 1 and No. 1 No. 7 silicone rubber sheet and TSE2 manufactured by Toshiba Silicone Co., Ltd. which is commercially available for heat resistance
For 323-5U (Reference Example), a test piece having a thickness of 12 mm was prepared, and left at 300 ° C. for 72 hours while being compressed by 25% in the thickness direction. The hardness (surface layer) before the test and after the compression was released was measured. Table 6 shows the results.

[0058]

[Table 6]

No. In each of Example 1 and Reference Example, remarkable hardening proceeded in the surface layer portion, softening occurred inside, and discoloration occurred. It is considered that the inside became hard to contact with air due to the hardening of the surface layer into a resin state, and the softening and deterioration were advanced. On the other hand, No. In No. 7, the degree of curing was small, no difference was observed between the surface layer portion and the inside, and rubber elasticity was maintained as a whole.

[0060]

The composition for a heat-resistant silicone rubber of the present invention can provide a heat-resistant silicone rubber which can withstand continuous use at a high temperature of 300 ° C. Further, the heat-resistant silicone rubber of the present invention can continue to maintain rubber elasticity even when kept at 300 ° C. in a compressed state.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4J002 CP031 DE118 DJ016 DL009 EK037 EK047 EK057 EK087 FB006 FD016 FD069 FD098 GJ02

Claims (5)

[Claims] (A) an average unit formula of R _a SiO _{(4-a) / 2} (where R is a substituted or unsubstituted monovalent hydrocarbon group, a = 1.9)
5 to 2.05)
100 parts by mass (B) Silica-based filler 5 to 100 parts by mass (C) Curing agent 0.01 to 5 parts by mass (D) Bengala 0.1 to 5 parts by mass (E) Glass 0.1 to 5 parts by mass A heat-resistant silicone rubber composition to be contained. 2. The heat-resistant silicone rubber composition according to claim 1, wherein the curing agent is an organic peroxide. 3. The glass has a diameter of 3 to 20 μm and a length of 5 μm.
The composition for a heat-resistant silicone rubber according to claim 1, wherein the composition is at least one selected from the group consisting of glass fibers having a size of 0 to 150 μm, glass particles having a particle size of 10 to 300 μm, and glass powder having a size of 150 mesh or less. . 4. The bengara has a particle size of 0.2 to 50 μm.
The composition for a heat-resistant silicone rubber according to any one of claims 1 to 3, wherein 5. A silicone rubber obtained by vulcanizing the composition according to claim 1, wherein the silicone rubber has a JIS-A hardness of 5 to 90.