JPH0150582B2 - - Google Patents

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention relates to a silicone rubber molded article and a method for producing the same, and more specifically relates to an unvulcanized conductive silicone rubber containing carbon black and an unvulcanized conductive silicone rubber containing no carbon black. The present invention relates to a silicone rubber molded article formed by adhering vulcanized silicone rubber and curing it by heating, and a method for producing the same.

[Technical Background of the Invention and Problems Therewith] A silicone rubber molded article is a silicone rubber molded article in which a conductive silicone rubber cured body portion containing carbon black and a silicone rubber cured body portion that does not substantially contain carbon black are integrated. It is widely used as various electrical components such as electrical contacts such as dichroic rubber contacts and zebra-type connectors, and gaskets for electromagnetic shielding.

As a method for manufacturing this type of silicone rubber molded article, Japanese Patent Publication No. 56-41417 discloses that an organic peroxide is added to unvulcanized silicone rubber containing carbon black, and conductive silicone rubber is cured by heat compression molding or the like. Then, an organic peroxide with an activation energy of 33 kcal/mol or more is added to an insulating unvulcanized silicone rubber that does not substantially contain carbon black, and the mixture is heated and compressed together with the above cured product. A method for manufacturing a silicone rubber molded article in which a conductive silicone rubber cured body part and an insulating silicone rubber cured body part are integrated is disclosed.

In addition, JP-A-58-171442 discloses that a conductive silicone rubber cured product containing 5 to 75% by weight of carbon black is used with a platinum-based catalyst to produce an unvulcanized product that does not substantially contain addition-reactive carbon black. A silicone rubber molded article in which insulating silicone rubber is adhered and heat-cured and a method for manufacturing the same are disclosed.

Furthermore, JP-A No. 58-205761 discloses that a conductive silicone rubber cured product using a platinum-based catalyst containing carbon black substantially contains a non-acyl organic peroxide. Disclosed is a silicone rubber molded article in which unvulcanized silicone rubber is closely adhered and heat-cured, and a method for producing the same.

However, in all of the above methods, the conductive silicone rubber is first heat-cured, and then the unvulcanized insulating silicone rubber is brought into close contact with the rubber and heat-cured, resulting in a two-step process, which poses problems in terms of mass production. Furthermore, all of them use non-acyl organic peroxides and are unsuitable for extrusion molding.

Furthermore, when various types of silicone rubber are integrally molded, a method is generally used in which an acyl organic peroxide is mixed with the silicone rubber as a vulcanizing agent, the mixture is simultaneously extruded using a multi-screw extruder, and the mixture is heated and cured.

On the other hand, in the combination of conductive silicone rubber containing carbon black and insulating silicone rubber that does not substantially contain carbon black,
Since the carbon black in the conductive silicone rubber inhibits curing of the acyl organic peroxide, a platinum catalyst is used as the curing agent for the conductive silicone rubber.

However, this method has a problem in that the adhesion between the two silicone rubbers when integrally molded is extremely poor and impractical.

[Object of the Invention] In order to solve the problems of the prior art, the present inventors added poly to an insulating silicone rubber that is vulcanized with an acyl organic peroxide and is substantially free of carbon black. It has been discovered that by adding organohydrogensiloxane and integrally molding, a silicone rubber molded article in which conductive silicone rubber using a platinum catalyst and insulating silicone rubber are firmly adhered can be obtained.

The present invention has been made based on this knowledge, and an object of the present invention is to provide a silicone rubber molded article in which a conductive portion and an insulating portion are bonded firmly and with good durability, and a method for manufacturing the same.

[Summary of the Invention] That is, the silicone rubber molded article of the present invention comprises: (A) one type of organic group having an average degree of polymerization of 500 to 12,000 and at least two of the organic groups bonded to silicon atoms in one molecule are vinyl groups; 100 parts by weight of two or more types of polydiorganosiloxane, 5 to 75 parts by weight of carbon black, and 0.1 to 10 parts by weight of polyorganohydrodiene siloxane in which the average number of hydrogen atoms bonded to silicon atoms exceeds 2 per molecule. 0.2 to 300 ppm of platinum or platinum compound, as platinum atoms, based on the total amount of
(B) an unvulcanized conductive silicone rubber portion whose main component is a composition containing (B) an average degree of polymerization of 500 to 12,000, and at least two of the organic groups bonded to silicon atoms in one molecule are vinyl groups; 100 parts by weight of one or more polydiorganosiloxanes, and 10 to 10 parts by weight of reinforcing and/or non-reinforcing fillers.
200 parts by weight, 0.1 to 10 parts by weight of an acyl organic peroxide, and 0.1 to 5 parts by weight of a polyorganohydrodiene siloxane having an average of more than 2 silicon-bonded hydrogen atoms per molecule. It is characterized in that it is made by integrating a composition containing a composition containing carbon black as a main component and an unvulcanized silicone rubber part that does not substantially contain carbon black, and its manufacturing method is as described in (A) above.
The unvulcanized conductive silicone rubber cured body portion of (B) and the unvulcanized silicone rubber cured body portion that does not substantially contain carbon black are simultaneously extruded, brought into close contact, and cured by heating. It is characterized by

(A) is the main material of (A) the conductive silicone rubber and (B) the insulating silicone rubber in the present invention.
Components (B) and (B) are those used as ordinary silicone rubbers, and may be the same or different from each other, and may be used alone or in combination of two or more. The repeating unit is dimethylsiloxy unit,
A polymer consisting of one or more diorganosiloxy units selected from phenylmethylsiloxy units, diphenylsiloxy units, methylvinylsiloxy units, phenylvinylsiloxy units, etc.
It is a copolymer or a mixture thereof, and must contain at least two vinyl groups in one molecule in order to obtain a rubber-like elastic body by curing.
Further, the terminal unit of this polydiorganosiloxane may be a triorganosiloxy group, a hydroxy group, or an alkoxy group.

Examples of the above triorganosiloxy group include trimethylsiloxy group, dimethylvinylsiloxy group, methylphenylvinylsiloxy group, methyldiphenylsiloxy group, and analogs thereof.

Furthermore, the average degree of polymerization of the polydiorganosiloxane used as component (A) and component (B) is 500.
~12000, preferably 1000-7000.
If it is less than 500, good mechanical properties cannot be obtained, and if it is less than 12,000
If it exceeds 20%, it becomes difficult to add conductive particles.

Examples of the carbon black of component (A) include channel black, phones black, thermal black, acetylene black, etc.
In particular, conductive grade is preferred. Conductive grades of carbon black are found in large numbers in Fornes black and acetylene black. The content of carbon black is 5 to 75 parts by weight per 100 parts by weight of component (A). If it is less than 5 parts by weight, the conductivity and adhesiveness will be insufficient, and if it exceeds 75 parts by weight, the processability will deteriorate and it will not be practical.

The polyorganohydrodiene siloxane of component (A) acts as a crosslinking agent for component (A), and has an average number of at least two hydrogen atoms bonded to silicon atoms per molecule to form a network structure. There is a need.

Examples of the organic group bonded to the silicon atom include those similar to the organic group bonded to the silicon atom of the polydiorganosiloxane (A). The average degree of polymerization of this polyorganohydrodiene siloxane is not particularly limited, but it is difficult to synthesize one in which two or more hydrogen atoms are bonded to the same silicon atom, so it is preferably composed of three or more siloxy units. .

The siloxane skeleton of component (A) may be linear, cyclic, or branched.

The blending amount of component (A) is 0.1 to 10 parts by weight per 100 parts by weight of component (A), preferably 1 to 1 silicon-bonded vinyl group of component (A).
0.5 to 15 hydrogen atoms bonded to silicon atoms in the component
The amount is preferably in the range of 1.5 to 5. Even if the amount of component (A) is less than 0.1 part by weight
Even if the amount exceeds 10 parts by weight, a rubber toxicant with excellent physical properties cannot be obtained.

Component (A) is a curing catalyst for providing a rubber-like elastic body through an addition reaction between components (A) and (A).

Components (A) include platinum black, monolithic platinum, platinum tetrachloride, chloroplatinic acid and its alkali metal salts, alcohol modified products, platinum-olefin complex, platinum-vinylsiloxane complex, platinum-phosphine. Examples include complexes, platinum-phosphite complexes, etc., but alcohol-modified chloroplatinic acid, platinum-olefin complexes, platinum-vinylsiloxane complexes, etc. preferable.

The blending amount of component (A) is 0.2 in terms of the amount of platinum atoms based on the total amount of each component (A), (A), and (A).
-300ppm, preferably 1-100ppm.
If it is less than 0.2 ppm, the curing speed will be slow, causing stickiness in the cured product and inhibiting removability, and if it exceeds 300 ppm, the curing speed will be too fast, impairing workability.
It is also uneconomical.

In addition to the above components, in the present invention, necessary amounts of addition reaction inhibitors such as acetylene compounds, diallyl maleate, triallylisocyanurate, nitrile compounds, and organic peroxides are added to extend the curing time at room temperature. It can also be blended.

In order to further increase the mechanical strength, it is also possible to add known reinforcing filler silica used in conventional silicone rubbers.

Examples of such silica include fumed silica, precipitated silica, pyrogenic silica, and silica aerogel.

These reinforcing filler silicas may be surface-untreated or previously surface-treated with an organosilicon compound such as organochlorosilane, polydiorganosiloxane, hexaorganodisilazane, or Surface treatment with an organosilicon compound such as disilazane may be used.

Such surface treatment of filler silica can be performed by any known method. In addition to these components, cerium hydroxide, for example, can also be added as a heat-resistant additive.

This cerium hydroxide powder has an average particle size of
A material having a diameter of 50 μm or less is suitable, and is blended in an amount of 0.1 to 10 parts by weight per 100 parts by weight of component (A). Further, if necessary, an adhesion improver such as polysiloxane in which a side chain containing a trialkoxysilylalkyl group or an ester bond is bonded to a silicon atom may be added. In addition, desired amounts of other heat-resistant additives, antioxidants, processing aids, non-reinforcing fillers such as quartz powder and diatomaceous earth, and flame retardants may be added as necessary.

In addition, unvulcanized silicone rubber that does not substantially contain carbon black, which is component (B) in the present invention, does not contain carbon black at all, or contains only a small amount of carbon black necessary for coloring or flame retardation. It is an unvulcanized silicone rubber containing

The filler component (B) provides mechanical strength to the silicone rubber (B), and is a known reinforcing and non-reinforcing filler used in conventional silicone rubbers.

Examples of such reinforcing filler silica include fumed silica, precipitated silica, pyrogenic silica, and silica aerogel.

These reinforcing filler silicas may be surface-untreated or previously surface-treated with an organosilicon compound such as organochlorosilane, polydiorganosiloxane, hexaorganodisilazane, or Surface treatment with an organosilicon compound such as disilazane may be used.

Such surface treatment of filler silica can be performed by any known method.

In addition, non-reinforcing fillers include crushed quartz, diatomaceous earth, and the like. One or more kinds of these fillers can be selected according to each requirement, and the amount of the fillers to be added can be arbitrarily selected.

The blending amount of component (B) is 10 to 200 parts by weight per 100 parts by weight of component (B). If it is less than 10 parts by weight, the necessary mechanical strength cannot be obtained, and if it exceeds 200 parts by weight, extrusion molding is impossible.

The acyl organic peroxide of component (B) is
It is a necessary and important component for vulcanizing the silicone rubber (B) using a mold or extrusion molding and vulcanizing it with hot air. Examples of the acyl organic peroxide include 2,4-dichlorobenzoyl peroxide, p-chlorobenzoyl peroxide, and benzoyl peroxide.

The blending amount of (B) is 0.1 per 100 parts by weight of component (B).
~10 parts by weight, preferably 0.2 to 5 parts by weight. If it is less than 0.1 part by weight, sufficient vulcanization will not take place, if it is used in excess of 10 parts by weight, the curing rate will not change, and if it is used in excess, decomposition products will remain, which will adversely affect heat resistance.

Component (B), polyorganohydrodiene siloxane, is a necessary and important component for integrating the silicone rubber of the present invention and obtaining a molded article. In order for (B) to obtain the necessary adhesion function, the number of hydrogen atoms bonded to silicon atoms must be present in one molecule, on average, at least two.

Examples of the organic group bonded to the silicon atom include those similar to the organic group bonded to the silicon atom of the polydiorganosiloxane (B). The average degree of polymerization of this polyorganohydrodiene siloxane is not particularly limited, but since it is difficult to synthesize one in which two or more hydrogen atoms are bonded to the same silicon atom, it is preferably composed of three or more siloxy units. The siloxane skeleton may be linear, cyclic, or branched.

The amount of component (B) added is 0.1 to 5 parts by weight, preferably 0.2 to 2 parts by weight, per 100 parts by weight of component (B). If it is less than 0.1 parts by weight, good adhesive strength cannot be obtained, and if it exceeds 5 parts by weight, it will adversely affect the mechanical properties of the silicone rubber.

In the method of integrally molding silicone rubber in the present invention, (A) unvulcanized conductive silicone rubber and
It is also possible to adopt the method of (B) in which unvulcanized silicone rubber is molded, but in particular, when extruding them simultaneously using a twin-screw extruder to bring them into close contact with each other, and performing hot air vulcanization using a vulcanizing furnace, Since (A) and (B) are firmly integrated and a cured silicone rubber molded article can be continuously molded, it is advantageous in terms of characteristics and economy. Vulcanization temperature and time are 0.5 at 300-350℃
~1 minute is preferred. In addition, 150~ if necessary.
If secondary vulcanization is performed at 250° C. for 1 to 24 hours, residues from decomposition of the organic peroxide are removed, thereby stabilizing the conductive properties and mechanical properties, and improving the connection strength between the two.

[Effects of the Invention] According to the present invention, a silicone rubber molded article is obtained in which conductive silicone rubber containing carbon black and silicone rubber substantially free of carbon black are firmly integrated.

This silicone rubber molded product has a strong and durable bond between the conductive part and the insulating part.
Moreover, continuous molding is possible in one process, and two
It is extremely useful for application to various electrical parts such as colored rubber tactile conductors, ignition cables, and gaskets for electromagnetic shielding.

[Embodiments of the invention] The present invention will be explained below with reference to Examples.

Example 1 100 parts by weight of a positive organosiloxane consisting of 99.8 mol% dimethylsiloxy units and 0.2 mol% methylvinylsiloxy units and having an average degree of polymerization of 4000 and having a terminal dimethylvinylsiloxy unit and Denka Black (manufactured by Denki Kagaku Kogyo Co., Ltd.) (trade name) and 50 parts by weight were kneaded with a roll until uniform.

Add an isopropanol solution containing 1% by weight of chloroplatinic acid to 100 parts by weight of this mixture as platinum atoms.
Si-H at 50ppm and viscosity 21cSt at 25℃
2.0 parts by weight of polymethylhydrodiene siloxane having a content of 0.86% by weight and 0.05 parts by weight of methyl ethyl ketone peroxide as a reaction inhibitor were added and sufficiently kneaded to obtain an unvulcanized conductive silicone rubber.

Next, the average polymerization degree is 99.8 mol% of dimethylsiloxy units and 0.2 mol% of methylvinylsiloxy units, and the terminal is dimethylvinylsiloxy units.
100 parts by weight of 5000 polydiorganosiloxane;
45 parts by weight of fumed silica whose surface had been treated with tridimethylsiloxane was kneaded with a roll until uniform. This mixture has a viscosity of 21 cSt at 25°C.
Then, 0.5 parts by weight of polymethylhydrodiene siloxane with a Si-H content of 0.86% by weight and 1.5 parts by weight of 2,4-dichlorobenzoyl peroxide were added and thoroughly kneaded to obtain unvulcanized insulation properties. Silicone rubber was obtained.

By extruding these two types of silicone rubber at the same time using a twin-screw extruder, they are brought into close contact with each other.
Hot air vulcanization was performed in a vulcanization furnace set at 30 seconds for a residence time of 30 seconds to obtain a silicone rubber molded body in which a conductive silicone rubber cured body part and an insulating silicone rubber cured body part were integrated.

Example 2 Polydiorganosiloxane with an average degree of polymerization of 3000, in which 0.25 mol% of organic groups bonded to silicon atoms are vinyl groups, 8.5 mol% are phenyl groups, and the remainder is methyl groups, and the terminal is dimethylvinylsiloxy units. 100 parts by weight and 50 parts by weight of Denka Black (manufactured by Denki Kagaku Kogyo Co., Ltd., trade name) were kneaded with a roll until uniform.

Add an isopropanol solution containing 1% by weight of chloroplatinic acid to 100 parts by weight of this mixture as platinum atoms.
Si-H at 50ppm and viscosity 21cSt at 25℃
2.0 parts by weight of polymethylhydrodienesiloxane having a content of 0.86% by weight and 0.05 parts by weight of methyl ethyl ketone peroxide as a reaction inhibitor were added and thoroughly kneaded to obtain an unvulcanized conductive silicone rubber. .

Next, the average polymerization degree is 99.8 mol% of dimethylsiloxy units and 0.2 mol% of methylvinylsiloxy units, and the terminal is dimethylvinylsiloxy units.
100 parts by weight of 6000 polydiorganosiloxane;
40 parts by weight of fumed silica whose surface had been treated with tridimethylsiloxane and 1 part by weight of tetramethylcyclotetrasiloxane as a processing aid were kneaded with a roll until uniform.

This mixture was then given a viscosity of 21 cSt at 25°C.
Adding 0.5 parts by weight of polymethylhydrodiene siloxane with a Si-H content of 0.86% by weight and 1.5 parts by weight of 2,4-dichlorobenzoyl peroxide,
By sufficiently kneading, an unvulcanized insulating silicone rubber was obtained.

These two types of silicone rubber were brought into close contact with each other in the same manner as in Example 1, and heated and cured to obtain a silicone rubber molded body in which a conductive silicone rubber cured part and an insulating silicone rubber cured part were integrated. .

Example 3 100 parts by weight of polydimethylsiloxane, which has a dimethylvinylsiloxy unit at the end and has an average degree of polymerization of 4000, and 15 parts by weight of Ketsuen Black EC (manufactured by Lion Akzo Co., Ltd., trade name) were mixed with a roll until uniform. I practiced.

Add an isopropanol solution containing 1% by weight of chloroplatinic acid to 100 parts by weight of this mixture as platinum atoms.
Si-H at 50ppm and viscosity 21cSt at 25℃
1.5 parts by weight of polymethylhydrodiene siloxane having a content of 0.86% by weight and 0.05 parts by weight of methyl ethyl ketone peroxide as a reaction inhibitor were added and sufficiently kneaded to obtain an unvulcanized conductive silicone rubber.

This conductive silicone rubber and the unvulcanized insulating silicone rubber of Example 1 were cured in the same manner as in Example 1, so that the cured conductive silicone rubber portion and the cured insulating silicone rubber portion were integrated. A silicone rubber molded article was obtained.

Example 4 100 parts by weight of a polydiorganosiloxane consisting of 99.8 mol% dimethylsiloxy units and 0.2 mol% methylvinylsiloxy units and having an average degree of polymerization of 5000, which is terminally dimethylvinylsiloxy units, and a fume whose surface was treated with polydimethylsiloxane. quality silica
45 parts by weight were kneaded with a roll until uniform.
This has a viscosity of 21 cSt at 25°C and a Si-H content.
0.5 parts by weight of polymethylhydrodiene siloxane (0.86% by weight) and 1.2 parts by weight of p-chlorobenzoyl peroxide were added and sufficiently kneaded to obtain an unvulcanized insulating silicone rubber.

Two types of silicone rubber, this insulating silicone rubber and the unvulcanized conductive silicone rubber of Example 1, were extruded simultaneously using a twin-screw extruder to bring them into close contact, and the mixture was heated in a vulcanization furnace set at 350°C. Hot air vulcanization was carried out at a residence time of 1 minute to obtain a silicone rubber molded body in which a conductive silicone rubber cured body part and an insulating silicone rubber cured body part were integrated.

For the cured silicone rubber molded bodies of Examples 1 to 4, both cured body parts were pulled from both sides using a tensile tester equipped with an autograph, and the state of adhesion at the interface was observed. In all cases, the conductive silicone rubber cured body was broken and the interface remained intact.

Comparative Example 1 An unvulcanized conductive and insulating silicone rubber was obtained in the same manner as in Example 1 except that polymethylhydrodiene siloxane was not added in the preparation of the insulating silicone rubber. When these were extruded in the same manner as in Example 1 and cured by hot air vulcanization, both cured parts were not tightly adhered at the interface, and no integral molded product was obtained.

Comparative Example 2 The unvulcanized conductive silicone rubber of Example 1 was
A cured product was prepared by hot air vulcanization at 350°C for 30 seconds, and the unvulcanized insulating silicone rubber used in Comparative Example 1 was adhered to it, followed by hot air vulcanization at 350°C for 30 seconds to harden it. However, the two cured parts were not tightly adhered at the interface, and an integrated molded product could not be obtained.

Comparative Example 3 Two types of silicone rubber were obtained in the same manner as in Example 2, except that polymethylhydrodiene siloxane was not added in the preparation of the insulating silicone rubber. These were extruded in the same manner as in Example 1,
When the cured product was cured by hot air vulcanization, the two cured parts did not adhere tightly at the interface, and no integrated molded product could be obtained.

Comparative Example 4 100 parts by weight of dimethylpolysiloxane (average degree of polymerization 600) with both ends blocked with methylphenylvinylsilyl groups and 50 parts by weight of Denka Black were kneaded until uniform, and then dimethylsiloxane-methylhydrodienesiloxane copolymer was added. Coalescing (50 mol% dimethylsiloxane units, 50 mol% methylhydrogensiloxane units, viscosity 5 cSt at 25°C) 1.8
1.0 part by weight of an isopropanol solution of chloroplatinic acid (chloroplatinic acid content: 1% by weight) and 0.05 part by weight of methylbutynol were added and kneaded until homogeneous to obtain a conductive silicone rubber.

Next, 100 parts by weight of a raw copolymer rubber with an average degree of polymerization of 4000 consisting of 99.8 mol% dimethylsiloxane units and 0.2 mol% methylvinylsiloxane units and 40 parts by weight wet process silica were kneaded until uniform,
1.5 parts by weight of dicumyl peroxide was added to this and thoroughly kneaded to obtain an insulating silicone rubber.

When these two types of silicone rubber were extruded and hot-air vulcanized in the same manner as in Example 4, foaming occurred inside the insulating silicone rubber and a satisfactory integrally molded product could not be obtained.

Comparative Example 5 100 parts by weight of a raw copolymer rubber with an average degree of polymerization of 4000 consisting of 99.7 mol% of dimethylsiloxane units and 0.3 mol% of methylvinylsiloxane units and 15 parts by weight of Ketschen Black EC were kneaded until uniform,
Furthermore, the dimethylsiloxane used in Comparative Example 4
0.8 parts by weight of methyl hydrodiene siloxane copolymer and 0.2 parts by weight of a solution of chloroplatinic acid in isopropanol (chloroplatinic acid content: 1% by weight) were added and quickly kneaded to obtain a conductive silicone rubber.

Next, 100 parts by weight of the unvulcanized silicone rubber containing 28.6% by weight of the wet process silica used in Comparative Example 4 was added.
0.5 parts by weight of 2.5-dimethyl-2.5-di(t-butylperoxy)hexane was added and thoroughly kneaded to obtain an insulating silicone rubber.

When these two types of silicone rubber were extruded and hot air vulcanized in the same manner as in Example 4, foaming occurred inside the insulating silicone rubber side as in Comparative Example 4, and a satisfactory integrally molded product was not obtained. Nakatsuta.

Claims (1)

[Scope of Claims] 1 (A) One or more polydiorganosiloxanes 100 having an average degree of polymerization of 500 to 12,000 and in which at least two of the organic groups bonded to silicon atoms in one molecule are vinyl groups. parts by weight, 5 to 75 parts by weight of carbon black, 0.1 to 10 parts by weight of polyorganohydrodiene siloxane in which the average number of hydrogen atoms bonded to silicon atoms exceeds 2 per molecule, and platinum or a platinum compound. , as platinum atoms, 0.2 to 300 ppm relative to the total amount of and
(B) an unvulcanized conductive silicone rubber portion whose main component is a composition containing (B) an average degree of polymerization of 500 to 12,000, and at least two of the organic groups bonded to silicon atoms in one molecule are vinyl groups; 100 parts by weight of one or more polydiorganosiloxanes, and 10 to 10 parts by weight of reinforcing and/or non-reinforcing fillers.
200 parts by weight, 0.1 to 10 parts by weight of an acyl organic peroxide, and 0.1 to 5 parts by weight of a polyorganohydrodiene siloxane having an average of more than 2 silicon-bonded hydrogen atoms per molecule. What is claimed is: 1. A silicone rubber molded article, characterized in that the main component is a composition containing carbon black, and an unvulcanized silicone rubber portion substantially free of carbon black is integrated with the unvulcanized silicone rubber portion and cured by heating. 2 (B) 0.2% of the acyl organic peroxide component
The silicone rubber molded article according to claim 1, which contains up to 5 parts by weight. 3 (A) 100 parts by weight of one or more polydiorganosiloxanes having an average degree of polymerization of 500 to 12,000 and at least two of the organic groups bonded to silicon atoms in one molecule are vinyl groups, and carbon black. 5 to 75 parts by weight, 0.1 to 10 parts by weight of a polyorganohydrodiene siloxane in which the average number of hydrogen atoms bonded to silicon atoms exceeds 2 per molecule, platinum or a platinum compound as a platinum atom, and 0.2-300ppm for the total amount of
(B) an unvulcanized conductive silicone rubber part whose main component is a composition containing (B) an average degree of polymerization of 500 to 12,000, and at least two of the organic groups bonded to silicon atoms in one molecule are vinyl groups; 100 parts by weight of one or more polydiorganosiloxanes, and 10 to 10 parts by weight of reinforcing and/or non-reinforcing fillers.
200 parts by weight, 0.1 to 10 parts by weight of an acyl organic peroxide, and 0.1 to 5 parts by weight of polyorganohydrodiene siloxane in which the average number of hydrogen atoms bonded to silicon atoms exceeds 2 per molecule. Manufacture of a silicone rubber molded article, characterized in that a composition is the main component and an unvulcanized silicone rubber portion that does not substantially contain carbon black are simultaneously extruded to closely integrate them, and then heated and cured. Method.