KR101466257B1 - Liquid Silicone Rubber Composition for Insulator - Google Patents

Abstract

The present invention relates to linear polyorganosiloxanes comprising 0.001 to 5 mmol / g of alkenyl groups at both ends or side chains of the molecule, or both side chains and side chains, and having a viscosity at 25 DEG C of 100 to 20,000 mPa.s; A first polyorganohydrogenpolysiloxane containing 0.05 to 10 mmol / g of a hydrogen group in the side chain of the molecule; And a second polyorganohydrogensiloxane containing hydrogen groups at both ends of the molecule in an amount of 0.05 to 3.0 mmol / g, wherein the first polyorganohydrogen siloxane and the Si-H group of the second polyorganohydrogen siloxane And a molar ratio (H / Vi molar ratio) of the sum of the Si-vinyl groups of the polyorganosiloxane and the polyorganosiloxane is 1.2 to 2. The present invention also provides a liquid silicone rubber composition for an insulator.

Description

Technical Field [0001] The present invention relates to a silicone rubber composition for insulators,

The present invention relates to liquid silicone rubber compositions, and more particularly to silicone rubber compositions that can be used for insulators.

Liquid silicone rubber as a material for insulators is known to be superior to any other polymeric material due to its hydrophobicity.

Liquid silicone rubber suppresses leakage current, reduces the risk of flashover, and it is not necessary to clean the insulator when the insulator is made of liquid silicone rubber. Therefore, studies for manufacturing insulators with silicone rubber have been actively conducted, The use is generalized, and some use is done in Korea.

However, conventionally developed insulator liquid silicone rubbers have a problem in that the viscosity is high and the formability is very poor when a hollowcore insulatror for high voltage is manufactured.

KR 10-2006-0092089 A

An object of the present invention is to provide a silicone rubber composition for an insulator having low flame retardancy, mechanical properties, and insulation properties while having low moldability and high moldability, and a method for producing the same.

More particularly, the present invention relates to a silicone rubber composition for an insulator, which comprises 0.001 to 5 mmol / g of an alkenyl group at both ends or side chains of a molecule or both side chains and side chains and has a viscosity at 25 DEG C of 100 to 20,000 mPa lt; / RTI > linear polyorganosiloxane; A first polyorganohydrogenpolysiloxane containing 0.05 to 10 mmol / g of a hydrogen group in the side chain of the molecule; And a second polyorganohydrogensiloxane containing hydrogen groups at both ends of the molecule in an amount of 0.05 to 3.0 mmol / g, wherein the first polyorganohydrogen siloxane and the Si-H group of the second polyorganohydrogen siloxane And a molar ratio (H / Vi molar ratio) of the sum of the Si-vinyl groups of the polyorganosiloxane and the polyorganosiloxane is 1.2 to 2. The present invention relates to a liquid silicone rubber composition for an insulator.

In the present invention, the polyorganosiloxane is represented by the following formula (1), the first polyorganohydrogen siloxane is represented by the following formula (2), and the second polyorganohydrogen siloxane is represented by the following formula (3).

[Chemical Formula 1]

R-Si (R ¹ ) ₂ O (R ¹ ₂ SiO) _n Si (R ¹ ) ₂ -R

R represents an aliphatic unsaturated hydrocarbon having 1 to 20 carbon atoms, R1 is an aliphatic unsaturated hydrocarbon having 1 to 20 carbon atoms or an aliphatic hydrocarbon having 1 to 20 carbon atoms, and n is an integer of 50 to 500.

(2)

R-Si (R ¹ ) ₂ O (R ¹ HSiO) _m (R ¹ ₂ SiO) _n Si (R ¹ ) ₂ -R

R is an aliphatic saturated hydrocarbon or aromatic hydrocarbon having 1 to 20 carbon atoms, R1 is an aliphatic saturated hydrocarbon having 1 to 20 carbon atoms, and m and n are each independently an integer of 1 to 100.

(3)

HSi (R ¹ ) ₂ O (R ¹ ₂ SiO) _m Si (R ¹ ) ₂ H

Herein, R 1 is an aliphatic saturated hydrocarbon or aromatic hydrocarbon having 1 to 20 carbon atoms, and m is an integer of 5 to 50.

In the liquid silicone rubber composition for an insulator according to the present invention, the content of the polyorganosiloxane, the first polyorganohydrogen siloxane and the second polyorganohydrogen siloxane is not particularly limited, but the content of the polyorganosiloxane,

The first polyorganohydrogen siloxane is contained in an amount of 1 to 10 parts by weight,

The second polyorganohydrogen siloxane may be included in an amount of 1 to 20 parts by weight.

The liquid silicone rubber composition for an insulator of the present invention may further contain 15 to 35 parts by weight of fumed silica having a specific surface area (by BET method) of 50 m < 2 > / g or more with respect to 100 parts by weight of the polyorganosiloxane, Titanium dioxide having an average particle size of 0.1 to 1 占 퐉 in an amount of 90% or more and 5 to 10 parts by weight with respect to 100 parts by weight of the polyorganosiloxane may be further contained, and carbon black, azodicarbonamide, May be included. The content of the carbon black, the azodicarbonamide, the platinum compound and the curing retardant is not particularly limited, but it is preferable that the content of the carbon black is 0.1 to 0.5 parts by weight based on 100 parts by weight of the polyorganosiloxane, 0.1 to 0.5 parts by weight of the platinum compound, 0.1 to 0.2 parts by weight of the platinum compound, and 0.02 to 0.5 parts by weight of the curing retardant.

The silicone rubber composition for insulators according to the present invention has a very low viscosity and is easy to mold the insulator, exhibits excellent insulating properties and flame retardancy suitable for insulators after curing, and exhibits a change in hardness even under severe conditions during use (salt water, high temperature, ultraviolet ray) It is possible to exhibit stable physical properties for a long period of time.

Further, it is possible to manufacture a molded article without bubbles or defects by using a mold without pressing in a complicated large mold.

Before describing the present invention in detail, it is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the invention, which is defined solely by the appended claims. shall. All technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art unless otherwise stated.

Throughout the description and claims, unless the context requires otherwise, the word "comprise" is intended to include the stated article, step or group of articles, and steps; It is not meant to exclude an object, step or group of objects or a group of steps.

On the contrary, the various embodiments of the present invention can be combined with any other embodiments as long as there is no clear counterpoint. In particular, any feature that is indicated to be advantageous or advantageous may be combined with any other feature or feature that is indicated to be advantageous or advantageous.

The insulator silicone rubber composition according to one aspect of the present invention comprises a polyorganosiloxane, a first polyorganohydrogen siloxane, a second polyorganohydrogen siloxane, and a reinforcing silicate, wherein the H / Vi molar ratio is 1.2 Lt; / RTI >

1. Polyorganosiloxane

The polyorganosiloxane used in the present invention is represented by the following chemical formula (1), and contains 0.001 to 5 mmol / g of alkenyl groups at both ends and / or side chains of the molecule and has a viscosity at 25 ° C of 100 to 20,000 mPa · s. s. < / RTI >

[Chemical Formula 1]

R-Si (R ¹ ) ₂ O (R ¹ ₂ SiO) _n Si (R ¹ ) ₂ -R

R represents an aliphatic unsaturated hydrocarbon having 1 to 20 carbon atoms, R1 is an aliphatic unsaturated hydrocarbon having 1 to 20 carbon atoms or an aliphatic hydrocarbon having 1 to 20 carbon atoms, and n is an integer of 50 to 500.

When R 1 is an aliphatic unsaturated hydrocarbon, R may be a vinyl group, an allyl group, a butenyl group, a pentenyl group, a hexenyl group, a heptenyl group and the like. When the aliphatic hydrocarbon group is methyl, ethyl, Can be used.

The alkenyl group is included at both ends and / or side chains of the polyorganosiloxane molecule. The alkenyl group is preferably contained in an amount of 0.001 to 5 mmol per gram of polyorganosiloxane, more preferably 0.01 to 3 mmol / g.

If the content is less than 0.001 mmol / g, there is a problem that the mechanical properties are lowered and the viscosity is increased. If the content exceeds 5 mmol / g, tackiness may occur on the surface of the silicone rubber due to the residual alkenyl group .

The viscosity of the polyorganosiloxane is preferably 50 to 50,000 mPa.s at 25 deg. If the viscosity is less than 50 mPa.s, the mechanical properties (strength, etc.) of the silicone rubber coating may be lowered, and if the viscosity exceeds 50,000 mPa.s, it is required for high-capacity injection such as a hollow core insulator The viscosity may be exceeded and the workability may be deteriorated.

The reason for using polyorganosiloxane is because of the hydrophobicity, electrical insulation, weatherability, and stain resistance imparted by the siloxane structure, and satisfies the properties required by the insulator. The siloxane polymer structure having a Si-O bond has ion-binding properties unlike a polymer structure having a carbon-carbon bond, so that the molecular structure is not rigid, is flexible, and the intermolecular bonding force is weaker than that of carbon- It has excellent heat resistance and cold resistance, and Si-O bonding energy is higher than CC bonding energy, so it is excellent in heat resistance and weather resistance.

The hydrophobicity and low specific gravity of polyorganosiloxane is less than that of agglomerates made of inorganic materials such as ceramics and glass, so that it is easy to move, and there is no problem of breakage due to the advantage of rubber and high hydrophobicity, The pollutants generated on the surface of the city are self-cleaning that can be washed down by rainwater. Due to this specificity, inorganic and organic materials such as ceramics, glass, EPDM, and epoxy are being replaced.

Examples of the polyorganosiloxane that can be used in the present invention include vinyl-terminated polydimethylsiloxane, vinyl-terminated vinylmethyldimethylcopolymer, allyl-terminated polydimethylsiloxane, allyl-terminated vinylmethyldimethylcopolymer, butenyl-terminatedpoly-dimethylsiloxane and butenyl-terminated vinylmethyldimethylcopolymer.

2. The first polyorganohydrogensiloxane

The first polyorganohydrogen siloxane used in the present invention is represented by the following formula (2), and is a polyorganohydrogensiloxane containing a hydrogen group in a side chain of the molecule in an amount of 0.05 to 10 mmol / g.

(2)

R-Si (R ¹ ) ₂ O (R ¹ HSiO) _m (R ¹ ₂ SiO) _n Si (R ¹ ) ₂ -R

Wherein each R is an aliphatic saturated hydrocarbon or aromatic hydrocarbon having 1 to 20 carbon atoms, R1 is an aliphatic saturated hydrocarbon having 1 to 20 carbon atoms, and m and n are each independently an integer of 1 to 100.

R may be methyl, ethyl, butyl, phenyl or the like, and R1 may be methyl, ethyl, butyl, phenyl or the like (preferably methyl).

The hydrogen group contained in the molecular side chain is preferably contained in an amount of 0.05 to 10 mmol per g of the polyorganohydrogen siloxane. If the content is less than 0.05 mmol / g, the strength and mechanical strength of the silicone rubber may be weakened, and if the content exceeds 10 mmol / g, the silicone rubber hardness may increase.

The first polyorganohydrogen siloxane is used in an amount of 1 to 10 parts by weight based on 100 parts by weight of the polyorganosiloxane, more preferably 3 to 7 parts by weight based on 100 parts by weight of the polyorganosiloxane. If the content is less than 3 parts by weight, curing may not occur or crosslinking density may be lowered. If the content is more than 7 parts by weight, foaming may occur due to the dehydrogenation reaction, or there may be a problem in releasability.

The reason why the first polyorganohydrogensiloxane is used is that it functions as a crosslinking agent while imparting the same function as the polyorganosiloxane.

In the present embodiment, the first polyorganohydrogen siloxane may be polymethylhydrogensiloxane, polymethylhydrogen, dimethylcopolymer, polyethylhydrogensiloxane, poly-methylhydrogen, diethylcopolymer, or the like.

3. A second polyorganohydrogensiloxane

The second polyorganohydrogensiloxane used in the present invention is a polyorganohydrogensiloxane represented by the following formula (3) and containing hydrogen groups at both ends of 0.05 to 3.0 mmol / g.

(3)

HSi (R ¹ ) ₂ O (R ¹ ₂ SiO) _m Si (R ¹ ) ₂ H

In this case, each R1 is an aliphatic saturated hydrocarbon or aromatic hydrocarbon having 1 to 20 carbon atoms, such as methyl, ethyl, butyl, phenyl, etc., and m is an integer of 5 to 50.

It is preferable that the hydrogen group contained in the molecular end is contained in an amount of 0.005 to 3 mmol per g of polyorganohydrogensiloxane. If the content is less than 0.005 mmol / g, the mechanical strength of the silicone rubber may be weakened. If the content is more than 3 mmol / g, the working time may be shortened and the workability may be impaired.

The preferable content of the second polyorganohydrogen siloxane is 1 to 20 parts by weight based on 100 parts by weight of the polyorganosiloxane, and more preferably 4 to 10 parts by weight with respect to 100 parts by weight of the polyorganosiloxane. If the amount is less than 4 parts by weight, the tear strength may be weak and the crosslinking density may be lowered. If the amount is more than 10 parts by weight, the working time may be shortened and the workability may be deteriorated.

The reason why the second polyorganohydrogensiloxane is used is that it functions as a cross-linking agent while imparting the same function as the polyorganosiloxane and improves the mechanical strength, particularly the tear strength, of the silicone rubber.

In the present embodiment, the second polyorganohydrogen siloxane may be H-terminated polydimethyl-siloxane, H-terminated polydiethylsiloxane, H-terminated polydibutylsiloxane, or the like.

At this time, by adjusting the molar ratio of H / Vi, that is, the sum of the Si-H groups of the first polyorganohydrogensiloxane and the second polyorganohydrogensiloxane and the Si-vinyl group of the polyorganosiloxane, And at the same time reduce the change in hardness. For this, the H / Vi molar ratio is preferably 1.2 to 2. When the ratio is less than 1.2, the mechanical properties and hardness of the silicone rubber can not be obtained while the viscosity is low, and when the ratio is more than 2, the hardness varies depending on the flow rate.

4. Reinforcing silica

The reinforcing silica is used to improve the strength of the silicone rubber, and fumed silica having a specific surface area (BET method) of 50 m 2 / g or more can be used. Preferably, fumed silica is used in an amount of 200 to 300 m < 2 > / g, for example, D200 and D300 produced by KCC may be used.

The reinforcing silica is preferably contained in an amount of 15 to 35 parts by weight based on 100 parts by weight of the polyorganosiloxane.

If the amount is less than 15 parts by weight, the mechanical strength of the silicone rubber may be lowered. If the amount is more than 35 parts by weight, the silicone rubber molding viscosity may be too high to be suitable for large-volume injection such as a hollow core insulator.

5. Titanium Dioxide

Titanium dioxide may be further included for tracking performance of the insulator silicone rubber.

At this time, it is preferable to use titanium dioxide of the rutile type, and the titanium dioxide has a purity of 90% or more and an average particle size of 0.1 to 1 占 퐉.

The titanium dioxide is preferably contained in an amount of 5 to 10 parts by weight based on 100 parts by weight of the polyorganosiloxane. If the amount is less than 5 parts by weight, the tracking resistance tends to deteriorate. If the amount is more than 10 parts by weight, the viscosity tends to be high and the workability is deteriorated.

6. Remaining constituents

(1) Carbon black

The carbon black can be used for improving the tracking resistance performance. The carbon black is preferably contained in an amount of 0.1 to 0.5 parts by weight based on 100 parts by weight of the polyorganosiloxane. When the amount is less than 0.1 parts by weight, the tracking resistance may be deteriorated. When the amount is more than 0.5 parts by weight, conductive performance may be exhibited and tracking tracking performance may deteriorate.

(2) azodicarbonamide

The azo compound may be used to improve the flame retardancy of the silicone rubber, and the azo compound is preferably contained in an amount of 0.001 to 0.005 parts by weight based on 100 parts by weight of the polyorganosiloxane. When the amount is less than 0.001 parts by weight, the flame retardancy is not improved. When the amount is more than 0.005 parts by weight, the curing rate is delayed.

(3) Platinum compound

The addition reaction catalyst contained in the composition of the present invention is a component for promoting the addition reaction between the polyorganosiloxane component and the first and second polyorganosiloxane components

As the addition reaction catalyst, any catalyst capable of promoting the addition reaction between the polyorganosiloxane component and the first or second polyorganosiloxane component can be used without any particular limitation, and platinum, rhodium, palladium-based catalysts and the like can be used. A platinum compound is used.

In this case, the platinum in the platinum compound acts as a catalyst to crosslink the polyorganosiloxane containing an alkenyl group (e.g., a vinyl group) and the polyorganohydrogen siloxane.

The use of a compound having a zero oxidation number which forms a complex with a vinylsiloxane having a low molecular weight as a platinum compound can improve the reactivity and compatibility with the silicone polymer. Examples of the ligand that forms a complex with platinum in the platinum compound include divinyltetramethylsiloxane, tetramethyltetravinyltetracyclosiloxane, and the like, but the present invention is not limited thereto. The platinum content in the platinum compound is preferably 0.5 to 15% by weight.

The preferred content of the platinum compound is 0.1 to 0.2 parts by weight based on 100 parts by weight of the polyorganosiloxane. If the amount is less than 0.1 part by weight, the addition reaction of the composition may be significantly slowed or the curing itself may not be attained. If the content exceeds 0.2 parts by weight, the addition reaction may be accelerated and the pot life may be shortened, ..

(4) Hardener

Examples of the curing retarder include a double bond or a triple bond compound containing an alkenyl group such as 1-ethynyl-1-cyclohexanol, 1,1,3,3-tetramethyl-1,3-divinyldisilazane, 2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane, 2-methyl-3-butyn-2-ol and the like can be used but are not limited thereto. Is preferably 0.02 to 0.5 part by weight based on 100 parts by weight of the polyorganosiloxane. If the content is less than 0.02 parts by weight, a problem may occur due to an excessively high curing rate. If the content exceeds 0.5 parts by weight, curing itself may not be attained.

Example

Example 1

The components and contents as shown in Table 1 below were used to prepare a liquid silicone rubber composition for an insulator.

The manufacturing process of the liquid silicone rubber for the insulator is largely composed of two steps: a base compound manufacturing step and a dilution step. The base compound manufacturing step is a step of preparing a base compound by a dispersion process of a polyorganosiloxane and a fumed silica, and a diluting step is a step of diluting with a polyorganohydrogensiloxane and other additives.

To obtain the base compound, 28 parts by weight of reinforcing fumed silica (300 m 2 / g), 6 parts by weight of hexamethyldisilazane and 3 parts by weight of water were added to 100 parts by weight of vinyl-terminated polydimethyl-siloxane at room temperature for 30 minutes And refluxed for 1 hour at < RTI ID = 0.0 > 90-100 C. < / RTI > Next, the normal pressure and reduced pressure recovery process were performed at 140 to 160 ° C for 2 hours, and then the cooling process was performed.

To the thus obtained base compound, 0.13 part by weight of an addition reaction catalyst (PtViMM) and 0.05 part by weight of a curing retardant (1-ethynylcyclohexanol) were respectively mixed for 10 minutes. 5 parts by weight of a first polyorganohydrogen siloxane and a second polyorganohydrogensiloxane were added as crosslinking agents for 10 minutes or more. Subsequently, 6 parts by weight of titanium dioxide (TiO2), 0.2 part by weight of carbon black and 0.002 part by weight of azodicarbonamide were added and stirring was continued for 15 minutes to prepare an insulator liquid silicone rubber composition.

Example 2

A silicone rubber composition for an insulator was prepared in the same manner as in Example 1, except that the content of azodicarbonamide was different.

Comparative Example

Comparative Example 1

A silicone rubber composition for an insulator was prepared in the same manner as in Example 1, except that the amount of the first polyorganohydogenosiloxane was 8 g and the amount of polyorganohydrogensiloxane was 8 g.

Comparative Example 2

A silicone rubber composition for an insulator was prepared in the same manner as in Example 1 except that the amount of the first polyorganohydogenosiloxane was 11 g and the amount of polyorganohydrogensiloxane was 11 g.

The foregoing examples and comparative examples are summarized in Table 1.

division Example 1 Example 2 Comparative Example 1 Comparative Example 2 Furtherance
ingredient Polyorganosiloxane
100 100 100 100 The first polyorganohydrogen siloxane 5 5 8 11 The second polyorganohydrogen siloxane 5 5 8 11 Fumed silica 28 28 28 28 Titanium dioxide 6 6 6 6 Carbon black 0.2 0.2 0.2 0.2 Azodicarbonamide 0.002 0.004 0.002 0.002 Platinum compound 0.13 0.13 0.13 0.13 Hardening retarder 0.05 0.05 0.05 0.05 H / Vi mol ratio 1.7 1.7 2.7 3.7

Experimental Example

The physical properties such as viscosity, hardness, tensile strength, tear strength, elongation, specific gravity, dielectric breakdown, volume resistance, tracking resistance and arc resistance were tested for the above-mentioned Examples and Comparative Examples, Results were obtained.

division
Example 1 Example 2 Comparative Example 1 Comparative Example 2 Before curing
Properties Viscosity Pa.s 18 18 17 16 Mechanical
Properties



Hardness Shore 38 38 37 36 Hardness (after boiling) Shore 41 41 47 57 The tensile strength MPa 5.2 5.4 4.8 4.6 Phosphorus strength N / mm 22 21 25 27 Elongation % 400 380 410 420 importance - 1.12 1.12 1.11 1.12 Electrical
Properties


Dielectric breakdown kV / mm 25 24 24 24 Volume resistance
10 ¹³ Ω cm 1.5 1.8 1.5 1.5 Tracking resistance Rating 1A4.5 1A4.5 1A3.5 1A4.5 Arc arcability Sec. 420 420 420 420 Flammability UL94 Rating V0 V0 V0 V0

According to this, it can be seen that the embodiments have the characteristics of an ultra-low viscosity of 20 Pa.s or less (25 ° C, cone & plate viscometer, 10s-1) and a hardness change of less than 10%. However, in the comparative examples, it can be confirmed that the change in hardness exceeds 10%. At this time, the change in hardness was measured by changing the hardness of the cured specimen after it was terminated at 100 ° C for 72 hours in a 0.1% NaCl solution.

Claims (7)

Linear polyorganosiloxanes containing 0.001 to 5 mmol / g of alkenyl groups at both ends or side chains of the molecule or both side chains and side chains and having a viscosity at 25 DEG C of 100 to 20,000 mPa.s;
A first polyorganohydrogenpolysiloxane containing 0.05 to 10 mmol / g of a hydrogen group in the side chain of the molecule;
And a second polyorganohydrogenpolysiloxane containing hydrogen groups at both ends of the molecule in an amount of 0.05 to 3.0 mmol / g,
The molar ratio (H / Vi molar ratio) of the sum of the Si-H groups of the first polyorganohydrogensiloxane and the second polyorganohydrogensiloxane to the Si-vinyl groups of the polyorganosiloxane is 1.2 to 2,
Wherein the change in hardness after boiling at 100 占 폚 for 72 hours in 0.1% NaCl solution is within 10%.
The method according to claim 1,
The polyorganosiloxane is represented by the following general formula (1)
Wherein the first polyorganohydrogen siloxane is represented by the following formula (2)
And the second polyorganohydrogen siloxane is represented by the following formula (3).
[Chemical Formula 1]
R-Si (R ¹ ) ₂ O (R ¹ ₂ SiO) _n Si (R ¹ ) ₂ -R
(Wherein R represents an aliphatic unsaturated hydrocarbon having 1 to 20 carbon atoms, R1 is an aliphatic unsaturated hydrocarbon having 1 to 20 carbon atoms or an aliphatic hydrocarbon having 1 to 20 carbon atoms, and n is an integer of 50 to 500)
(2)
R-Si (R ¹ ) ₂ O (R ¹ HSiO) _m (R ¹ ₂ SiO) _n Si (R ¹ ) ₂ -R
(Wherein R is an aliphatic saturated hydrocarbon or aromatic hydrocarbon having 1 to 20 carbon atoms, R1 is an aliphatic saturated hydrocarbon having 1 to 20 carbon atoms, and m and n are each independently an integer of 1 to 100)
(3)
HSi (R ¹ ) ₂ O (R ¹ ₂ SiO) _m Si (R ¹ ) ₂ H
(Wherein R1 is an aliphatic saturated hydrocarbon or aromatic hydrocarbon having 1 to 20 carbon atoms, and m is an integer of 5 to 50)
The method according to claim 1,
With respect to 100 parts by weight of the polyorganosiloxane,
The first polyorganohydrogen siloxane is contained in an amount of 1 to 10 parts by weight,
And the second polyorganohydrogenpolysiloxane is contained in an amount of 1 to 20 parts by weight.
The method according to claim 1,
Wherein the fumed silica having a specific surface area (by the BET method) of 50 m < 2 > / g or more is further contained in an amount of 15 to 35 parts by weight based on 100 parts by weight of the polyorganosiloxane.
5. The method of claim 4,
Wherein the titanium dioxide having a purity of 90% or more and an average particle size of 0.1 to 1 占 퐉 is further contained in an amount of 5 to 10 parts by weight based on 100 parts by weight of the polyorganosiloxane.
6. The method of claim 5,
The insulator silicone rubber composition
Carbon black, azodicarbonamide, a platinum compound, and a curing retarder.
The method according to claim 6,
With respect to 100 parts by weight of the polyorganosiloxane,
Wherein the carbon black is 0.1 to 0.5 parts by weight, the azodicarbonamide is 0.001 to 0.005 parts by weight, the platinum compound is 0.1 to 0.2 parts by weight, and the curing retardant is 0.02 to 0.5 parts by weight, Composition.