KR102053591B1 - Sheath composition with low-temperature resistance and oil resistance - Google Patents

Abstract

The present invention relates to a sheath composition having cold resistance and oil resistance. Specifically, the present invention relates to a sheath composition that is not only environmentally friendly, such as not generating harmful substances such as toxic gases during combustion for disposal, but also exhibits cold resistance and oil resistance that are difficult to secure at the same time, and is excellent in intrinsic physical properties, flame retardancy, and fairness. .

Description

Sheath composition with cold resistance and oil resistance

The present invention relates to a sheath composition having cold resistance and oil resistance. Specifically, the present invention relates to a sheath composition that is not only environmentally friendly, such as not generating harmful substances such as toxic gases during combustion for disposal, but also exhibits cold resistance and oil resistance that are difficult to secure at the same time, and is excellent in intrinsic physical properties, flame retardancy, and fairness. .

The sheath layer of cables used in low temperature environments, such as ships or polar regions, which can be constantly affected by low temperature seawater, is resistant to low temperatures, i.e., if it does not have cold resistance, cracks may occur in the sheath layer. Therefore, damage may occur to the product or the insulation layer may not be protected inside the sheath layer.

In addition, since the sheath layer and the insulating layer therein are made of a polymer resin vulnerable to oil, the sheath layer may be oil, mud (mud) to effectively protect the sheath layer, the insulating layer, etc. made of such a polymer resin from the external oil. ), Ie oil resistance, mud resistance, etc. should be secured.

The cold resistance of the sheath layer is a property related to the glass transition temperature (Tg) of the polymer resin constituting the lower the glass transition temperature (Tg) is excellent in bringing fluidity at low temperatures. In this regard, polyethylene has a disadvantage of being vulnerable to oil, mud, etc. due to the absence of a polar group or a material having excellent low temperature properties having a low glass transition temperature (Tg) of -60 ° C.

In addition, in order to satisfy both the cold resistance and oil resistance of the sheath layer at the same time, a mixed use of polyethylene and a resin having a polar group may be considered. However, both cold resistance and oil resistance depend on the side chain, that is, the functional group, of the polymer main chain. It is difficult to satisfy oil resistance, mud resistance, etc., which are resistant to cold at low temperatures and vulnerable to polymers and mud.

On the other hand, chloroprene rubber, chlorosulfonated polyethylene, etc., which were used mainly as a cable sheath layer material having oil resistance, are excellent in oil resistance characteristics of the resin itself due to the inclusion of a halogen element and melting point due to the addition of a plasticizer. It was easy to satisfy the cold characteristic by the fall of. However, when the sheath layer produced using the resin is burned, toxic gases such as dioxins are released, and thus it is known that the human body is harmful to the environment. In relation to this, the development of new materials with relatively low hazards is being progressed along with the regulations for environmental protection or the interest of developing eco-friendly alternative materials.

In this regard, a technique of using an ethylene-vinyl acetate copolymer resin having a content of vinyl acetate of 70% for high oil resistance and adding a plasticizer for lowering the glass transition temperature (Tg) and a silica-based reinforcing material for improving mechanical strength (Reference: Korean Patent Registration Nos. 10-0627512 and 10-0635585) are disclosed. However, the above technique has a problem in that the compound viscosity is lowered and the sticky nature of the material itself is adhered to the metal compounding equipment, which leads to impossibility or a decrease in process capability. Furthermore, due to the low shear stress due to the decrease of the viscosity of the compound, the dispersibility of the silica-based reinforcement added for mechanical properties reinforcement is reduced, so that it is difficult to reproduce or maintain the tensile strength at room temperature and the quality of the material itself. have.

In addition, a technique using acrylonitrile butadiene rubber having a nitrile group for high oil resistance has been disclosed (see Japanese Patent Laid-Open Nos. 2007-028982 and 2007-077270), but this is due to insufficient heat resistance and rubber properties. There is a problem in that the modulus improvement is limited.

In addition, a technique of blending acrylonitrile butadiene rubber on fluorine rubber for compatibility with a plasticizer has been disclosed (see Japanese Patent Laid-Open No. 2003-268182), but the compatibility between the fluorine rubber and the plasticizer is still not solved. There is a problem that can not achieve the desired level of cold resistance.

In this situation, new sheath material and a sheath layer manufactured therefrom which are environmentally friendly, do not cause toxic gases during combustion, have excellent quality stability and process stability, and have excellent cold resistance, oil resistance, flexibility, and flame retardancy in the material itself. A power cable to say is required.

An object of the present invention is to provide an environmentally friendly sheath composition such that no harmful substances such as toxic gases are generated during combustion for cable disposal.

Moreover, an object of this invention is to provide the sheath composition which has both cold resistance and oil resistance which are difficult to ensure simultaneously.

In addition, an object of the present invention is to provide a sheath composition having quality stability and process stability by intrinsic physical properties such as heat resistance, flame retardancy, mechanical properties.

In order to solve the above problems, the present invention,

Silicone rubber having a molecular weight of 400,000 or more and less than 700,000 and having a tensile strength of 40 kgf / cm 2 or more, an elongation of 120% or more, and a shore A hardness of 30 or more (measured according to standard ASTM D 2240), the silicone rubber 100 A sheath composition is provided, comprising 50 to 150 parts by weight of reinforcing agent, and 1 to 7 parts by weight of curing agent, based on parts by weight.

Here, the silicone rubber provides a sheath composition, characterized in that the main raw material is at least one silicone gum selected from the group consisting of methyl silicone, methylphenyl silicone, methylvinyl silicone, methylphenylvinyl silicone and fluorine silicone. .

In addition, the silicone rubber provides a sheath composition, characterized in that the viscosity of 10 million cps or more.

On the other hand, the reinforcing agent is a dry or wet silica surface modified or not with at least one compound selected from the group consisting of amine, epoxy, thiol, carboxylic acid, sulfonic acid, phosphoric acid, phosphine and cyanic acid, the curing agent is benzoyl peroxide, An alkyl-based peroxide, dicumyl peroxide, or a combination thereof is provided, and a sheath composition is provided.

In addition, the silica is 3-aminopropyltrimethoxysilane, N-2-aminoethyl-3-aminopropyltrimethoxysilane, 3-glydoxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-isocyanatopropyltrimethoxysilane, N- (beta-aminoethyl) gamma-aminopropyltrimethoxysilane, N- (beta-aminoethyl) gamma-aminopropylmethyldimethoxysilane, gamma-ureidopropyl A sheath composition, which is trimethoxysilane or a dry silica that is a combination thereof, is provided.

In addition, the curing agent is 2,4-dichlorobenzoyl peroxide, benzoyl peroxide, p-chlorobenzoyl peroxide, 2,5-dimethyl-2,5-di (tert-butylperoxy) hexane, di (3-gold -Butyl) peroxide, dicumyl peroxide, tert-butyl cumyl peroxide, or a combination thereof, providing a sheath composition.

On the other hand, it provides a sheath composition, characterized in that it further comprises a heat-resistant improving agent, anti-scorch agent, flame retardant, mold release agent, or a combination thereof.

1 is a cross-sectional view schematically showing the cross-sectional structure of a power cable according to the present invention.
2 is a longitudinal sectional view schematically showing a cross-sectional structure of a power cable according to the present invention.

1 and 2 show an embodiment of a power cable according to the invention.

As shown in Figures 1 and 2, the power cable according to the present invention comprises at least one conductor (1) made of a conductive material such as copper, aluminum, insulating layer (2) made of an insulating polymer and surrounding each conductor (1) ), A bedding layer (3) that maintains the cross section of the cable in a circular shape and performs supplementary functions such as mechanical strength, watertightness, and flame retardancy, and braiding to compensate for the expansion and relaxation of the cable or to protect the inside of the cable from external impact or contamination. Layer 4, sheath layer 5 for cable protection, and the like.

Standards of the conductor 1, the insulating layer 2, the bedding layer 3, the braided layer 4, the sheath layer 5, and the like may vary according to the purpose of the cable, the transmission voltage, and the like. ), The material constituting the bedding layer 3 and the sheath layer 5 may be the same or different, respectively.

The insulating material for forming the insulating layer 2 of the power cable according to the present invention is not particularly limited as long as it has an insulating property. In particular, most of the polymer resin is an electrically insulating material, and therefore plays an important role as an insulating material. In order for electricity to flow, there must be positive charges or free electrons such as metals or ions that can move electrons, because polymers are made of covalent bonds between carbons, and thus have little such capability. For example, a polymer resin such as polyolefin such as polyvinyl chloride, polyethylene, polypropylene, ethylene / propylene / diene copolymer (EPDM), polyimide, polyamide imide, polyester, preferably the sheath layer 5 The same material as the material may be used as the insulating material for the insulating layer 2 of the cable.

The bedding layer 3 of the power cable according to the invention is a three-phase cable in which the cable comprises three conductors 1 arranged in a triangular shape as shown in FIGS. 1 and 2 as described above. It keeps the cross section circular and also supplements the mechanical strength, watertightness, flame retardancy, etc. of the cable.

The material forming the bedding layer 3 may vary according to the use of the cable, the transmission voltage, the use environment, and the like. For example, a composite flame retardant material or a polyolefin resin based on polyvinyl chloride resin, in particular ethylene-vinyl acetate ( It may be made of a halogen-free flame retardant composite material based on EVA) copolymer resin, and preferably made of the same material as the material of the sheath layer 5. The bedding layer 3 entirely encloses one or more conductors 1 wrapped in the insulating layer 2.

In addition, the power cable according to the present invention may have a structure in which the braided layer 4 formed by braided aggregation of copper or tin-plated copper wire is formed on the outer surface of the bedding layer 3. The braided layer 4 is configured to improve high tensile strength, load resistance, flame barrier function, and the like, in the case of a non-halogen resin cable conforming to the International Electrotechnical Commission (IEC) standard, in a hazardous area or an explosion-proof area. As the cable to be installed, a cable in which the braided layer 4 was built or externally used was used.

The power cable according to the present invention may comprise a sheath layer 5 made from a rubber composition comprising silicone rubber (hereinafter referred to as a 'silicone rubber composition') and surrounding the braided layer 4. The sheath layer 5 may be made of a silicone rubber composition other than a sheath material such as a crosslinking compound of conventional chlorosulfonated polyethylene (CSP) and non-halogen polyolefin (HF-PO). In addition, the insulating layer 2 and the bedding layer 3 may also be made of a silicone rubber composition made of the same material as the sheath layer 5.

The silicone rubber is a colorless or faint yellow elastic solid with slight fluidity even at room temperature, also called silicon rubber, and has a higher molecular weight than silicone oil, and has a molecular weight of several hundred thousand, preferably 400,000 to 700,000, and a viscosity of 1,000. It may be a high polymer (> 5,000 to 10,000 siloxane units) of more than 10,000 cps. Silicone gum, which is a main ingredient of the silicone rubber, may be methyl silicone, methylphenyl silicone in which a part of the methyl group is substituted with a phenyl group and / or a vinyl group, methylvinyl silicone, methylphenylvinyl silicone, fluorine silicone, or the like.

The silicone rubber composition may further comprise a reinforcing agent for mechanical strength. The content of the reinforcing agent may be 50 to 150 parts by weight based on 100 parts by weight of the silicone rubber. When the content of the reinforcing agent is less than 50 parts by weight, the mechanical strength, oil resistance, etc. of the silicone rubber composition may be lowered to satisfy the specification. When the content of the reinforcing agent is more than 150 parts by weight, the elongation of the silicone rubber composition may be lowered, and the cold resistance and flexibility may be reduced. Cracking may occur in the sheath layer 5 at low temperatures.

In the power cable according to the present invention, the reinforcing agent is not particularly limited, and may be, for example, dry or wet silica, preferably, the silica may be dry silica having a low moisture content, and a BET surface area of 150 to 400. M 2 / g.

In addition, the silica may be surface-treated with at least one selected from the group consisting of amine, epoxy, thiol, carboxylic acid, sulfonic acid, phosphoric acid, phosphine and cyanic acid. Since silica has a hydroxyl group (-OH) on its surface, it is incompatible with a relatively hydrophobic silicone rubber, and the surface-treated silica has a functional group capable of chemically bonding to the surface, thereby covalently bonding to the silicone rubber. Non-covalent bonding can be achieved, thereby improving compatibility with silicone rubber.

The surface treated or unsilica may have an average particle diameter of 5 to 500 nm. When the average particle diameter is less than 5 nm, the surface energy and cohesion of the silica particles may be increased, so that functional groups capable of chemical bonding on the silica surface may be difficult to be uniformly formed, and when the average particle diameter is greater than 500 nm, uniform dispersion may be difficult.

The surface treated silica is, for example, 3-aminopropyltrimethoxysilane, N-2-aminoethyl-3-aminopropyltrimethoxysilane, 3-glydopropylpropylmethoxymethoxy, 3-mercaptopropyl Trimethoxysilane, 3-isocyanatopropyltrimethoxysilane, N- (beta-aminoethyl) gamma-aminopropyltrimethoxysilane, N- (beta-aminoethyl) gamma-aminopropylmethyldimethoxysilane, Gamma-ureidopropyltrimethoxysilane, or combinations thereof.

The silicone rubber composition may further include a curing agent for crosslinking the silicone rubber. The content of the curing agent may be 1 to 7 parts by weight based on 100 parts by weight of the silicone rubber. When the content of the curing agent is less than 1 part by weight, the degree of crosslinking of the silicone rubber may be lowered, so that room temperature mechanical properties of the silicone rubber composition may not be maintained, and oil resistance and heat deformation characteristics may be lowered. Another addition reaction may be caused to decrease the physical properties of the silicone rubber composition.

In the power cable according to the present invention, the curing agent is not particularly limited, and for example, organic peroxides such as benzoyl peroxide, alkyl peroxide, dicumyl peroxide, specifically 2,4-dichlorobenzoyl peroxide, benzoyl peroxide, p-chlorobenzoyl peroxide, 2,5-dimethyl-2,5-di (tert-butylperoxy) hexane, di (tert-butyl) peroxide, dicumyl peroxide, tert-butyl cumyl peroxide, Or a combination thereof.

The silicone rubber composition may further include a heat improver, an anti-scoring agent, a flame retardant, a mold release agent, and the like, in addition to the reinforcing agent and the curing agent. In particular, the content of the flame retardant may be 50 to 100 parts by weight based on 100 parts by weight of the silicone rubber, when the content of the flame retardant is less than 50 parts by weight can not satisfy the vertical ladder flame retardant characteristics of the flame retardant standard is more than 100 parts by weight When the elongation and flexibility of the silicone rubber composition may be reduced.

The silicone rubber may have a molecular weight of several hundred thousand, preferably 400,000 to 700,000. When the molecular weight of the silicone rubber is less than 400,000, mechanical properties before and after heating, oil resistance and the like may be lowered. In addition, the silicone rubber may exhibit a tensile strength of 40 kgf / cm 2 or more, preferably 70 to 90 kgf / cm 2. When the tensile strength of the silicone rubber is less than 40 kgf / cm 2, it is unsuitable to the cable sheath standard, and it is inevitable to add an excessive amount of reinforcing agent to the silicone rubber composition, thereby reducing the flexibility and cold resistance of the silicone rubber composition.

In addition, the elongation of the silicone rubber may be 120% or more, preferably 300 to 500%. When the elongation rate of the silicone rubber is less than 120%, the sheath layer manufactured from the silicone rubber composition may not meet the cable sheath specification and the melt strength may be lowered, so that molding of the silicone rubber composition may be difficult during extrusion. And, the hardness of the silicone rubber may be 30 or more, preferably 50 to 80, based on Shore A hardness (ASTM D 2240), when the Shore A hardness of the silicone rubber is less than 30 of the silicone rubber composition Damage may be caused by external impact or scratch before and after extrusion, thereby lowering the mechanical strength of the silicone rubber composition.

EXAMPLE

Hereinafter, preferred embodiments of the present invention will be described in detail. However, the invention is not limited to the embodiments described herein but may be embodied in other forms. Rather, the embodiments introduced herein are provided so that the disclosure may be made thorough and complete, and to fully convey the spirit of the present invention to those skilled in the art.

1. Manufacturing Example

In order to evaluate the physical properties of the sheath layer 5 included in the power cable according to the present invention, the rubber compositions of Examples and Comparative Examples were prepared using the components and contents shown in Table 1 below. Here, the unit of content is parts by weight.

division Example Comparative example One 2 3 One 2 3 4 Silicone rubber a 100 Silicone rubber b 100 Silicone rubber c 100 Silicone rubber d 100 Silicone rubber e 100 Silicone rubber f 100 Non-halogen
Polyolefin 100 Reinforcement 100 100 100 100 40 40 100 Hardener 5 4 6 5 5 4 5 Flame retardant 100 80 80 100 100 40 150

-Silicone rubber a: methyl silicone, molecular weight 430,000, viscosity 35 million cps, tensile strength 50kgf / cm 2, hardness 60- silicone rubber b: methyl silicone, molecular weight 500,000, viscosity 42 million cps, tensile strength 55kgf / cm 2, hardness 42

-Silicone rubber c: methyl silicon, molecular weight 600,000, viscosity 60 million cps, tensile strength 60 kgf / ㎠, hardness 51

-Silicone rubber d: Methyl silicone, molecular weight 300,000, viscosity 25 million cps, tensile strength 32 kgf / ㎠, hardness 32

-Silicone rubber e: methyl silicone, molecular weight 350,000, viscosity 8 million cps, tensile strength 30 kgf / ㎠, hardness 24

-Silicone rubber f: methyl silicon, molecular weight 700,000, viscosity 9.2 million cps, tensile strength 42 kgf / ㎠, hardness 26

Non-halogen polyolefin: Ethylene vinyl acetate (manufacturer: Foundec, product name: MX-2220B; vinyl acetate content: 70%)

-Reinforcing agent: Silica (manufacturer: Rhodia, product name: zeosil 155PD)

-Curing agent: Peroxide (Manufacturer: PERGAN, Product Name: Peroxan PK 295P)

-Flame Retardant: Aluminum Hydroxide (Manufacturer: KC Chemical, Product Name: KH-101LP)

Insulating layer 2 consisting of ethylene / propylene / diene copolymer (EPDM) (manufacturer: Foundec, product name: RZ-P0098) and ethylene, a non-halogenated polyolefin, in a tin-coated copper wire (IEC 60228, class 5) of a constant length After forming a bedding layer 3 made of a vinyl acetate resin (70% vinyl acetate content) (manufacturer: Foundec, product name: MX-2220B), a continuous vulcanization plant (manufacturer: mace, product name: 110 mm SCV, cylinder and head) Each cable specimen (standard) was formed by forming the sheath layer 5 from the respective rubber compositions of Examples 1 to 3 and Comparative Examples 1 to 4 prepared at a crosslinking temperature of 220 to 240 ° C using a temperature of 30 ° C or lower). : 3 x 24 SQ).

2. Measurement and Evaluation of Physical Properties of Cable Specimen

end. Evaluation of mechanical properties at room temperature and after heating

The speed was measured at 250mm / min according to IEC 60811-1-1, -2 and the reference value is according to IEC 60092-359.

I. Oil and Mud Resistance Evaluation

Tensile residual, elongated residual, volume change, and mass change were measured after impregnation for the oil or mud specified in NEK 606/2004 for a specified temperature and time. Here, the tensile residual and elongated residuals were evaluated according to IEC 60811-2-1, and the volume change and mass change were evaluated according to ASTM 471.

All. Cold resistance evaluation

CSA 22.2 No. According to 38, a cable specimen of 130 mm length was left at -40 ° C, -50 ° C, and -60 ° C for 4 hours, and the weight of 1.35 kg was dropped from the height of 915 mm. Cracks should not occur in the above specimens.

la. Flame Retardant Rating

IEC 60332-3-22 cat. According to A, the flame length shall not exceed 2.5 m after applying a flame for 40 minutes to a cable of length 3.5 m.

hemp. Heat deformation evaluation

According to IEC 60811-3-1, measure the thickness change after applying a load of 80 mm length for 6 hours at 80 ° C using a standard blade.

bar. 10% modulus

In order to compare the flexibility of the sheath layer 5 according to the material, a modulus of 10% is compared in a stress-strain curve, and a smaller value is evaluated as being flexible.

The mechanical properties, oil / mud resistance, cold resistance, heat deformation, and 10% modulus of the cable specimens measured / evaluated according to the evaluation method are shown in Table 2 below.

Reference value Example Comparative example One 2 3 One 2 3 4 Room temperature The tensile strength
(kgf / ㎡) 0.92 0.987 1.02 0.95 0.77 0.86 0.88 0.94 Elongation (%) 120 288.18 350.1 400 180 301 140 170 After heating Tensile Residual (%) 70 98 112 89 62 73.9 68.22 98.55 Elongation Residual (%) 70 110 87 85 60.1 75 110.1 101.2 Oil resistance
(IRM902,
100 ° C, 168 hours) Tensile Residual (%) 70 104.66 98.76 99.87 73.31 102.44 71.12 74.33 Elongation Residual (%) 70 101.32 100.09 79.98 75.4 98.12 73.42 76.7 Oil resistance
(IRM903,
100 ° C, 168 hours) Tensile Residual (%) 70 93.11 94.56 89.99 67.14 91.09 75.4 94.23 Elongation Residual (%) 70 89.79 90.57 83.49 62.74 87.77 71.28 83.53 Volume change (%) ± 30 16.2 15.44 25.22 35.6 18.4 28.22 28.05 Mass change (%) ± 30 11.7 12.34 20.8 34.9 13.9 26.39 22.94 Resistance to mud
(oil based mud,
70 ° C, 56 days) Tensile Residual (%) 75 80.95 82.1 79.99 59.5 93 73.44 93.29 Elongation Residual (%) 75 78.94 76.42 78.82 55.4 92.7 75.12 84.4 Volume change (%) ± 20 17.4 15.5 18.66 39.8 28.12 25.44 16.62 Mass change (%) ± 15 15 13.66 18.77 37.4 20 25.7 12.82
Cold resistance -40 ℃ pass pass pass pass pass pass pass -50 ℃ pass pass pass pass pass pass fail -60 ℃ pass pass pass pass pass pass fail Flame Retardant ≤250 103 78 60 98 110 100 200 Heating deformation 80 ℃, 4 hours ≤50% 21 30 16.7 40.5 38.1 54.3 28.5 10%
Modulus kgf / ㎠ 8.64 9.01 8.01 6.4 7.12 8.11 10.98

As shown in Table 2, the cable specimen according to Comparative Example 1 has a low molecular weight of 300,000 and a tensile strength of 32 kgf / cm 2 of the silicone rubber constituting the sheath layer 5 thereof, the tensile strength at room temperature of the specimen The mechanical properties such as tensile residual and elongation after heating, and resistance to oil IRM903 and mud were not significantly lower than the reference value. In addition, the cable specimens according to Comparative Example 2 were silicone rubbers forming the sheath layer 5 thereof. Has a molecular weight of 350,000, a tensile strength of 30 kgf / cm 2, a Shore A hardness of 24, and a content of a reinforcing agent of 40 parts by weight, respectively, resulting in poor mechanical properties such as tensile strength at room temperature. It was confirmed that it is inferior to Examples 1-3.

In addition, the cable specimen according to Comparative Example 3 has a low Shore A hardness of 26, a reinforcing agent and a flame retardant content of the silicone rubber constituting the sheath layer 5 of 40 parts by weight, respectively, the tensile strength at room temperature of the specimen, the tensile residual after heating It was confirmed that the mechanical properties and the heat deformation of the back were poor, and the oil resistance to the oil IRM903 was inferior to those of Examples 1 to 3. In addition, it was confirmed that the heat deformation of the specimen exceeded the reference value and was poor.

Furthermore, the cable specimen according to Comparative Example 4 used a non-halogen polyolefin as the resin forming the sheath layer 5, which had poor cold resistance at -50 ° C and -60 ° C, and the oil resistance to oil IRM902 was Example 1 Inferior to 3 was confirmed.

On the other hand, the cable specimens according to Examples 1 to 3 include a sheath layer 5 made of silicone rubber which is excellent in oil resistance, flexibility, cold resistance, and other intrinsic physical properties, so that the overall room temperature, mechanical properties after heating, Oil resistance, mud resistance, cold resistance, flame resistance, heat resistance and the like were all satisfied with the reference value.

Although the present specification has been described with reference to preferred embodiments of the invention, those skilled in the art may variously modify and change the invention without departing from the spirit and scope of the invention as set forth in the claims set forth below. Could be done. Therefore, it should be seen that all modifications included in the technical scope of the present invention are basically included in the scope of the claims of the present invention.

1: conductor 2: insulation layer
3: bedding layer 4: braided layer
5: sheath layer

Claims (7)

Silicone rubber having a molecular weight of 400,000 or more and less than 700,000 and having a tensile strength of 40 kgf / cm 2 or more, an elongation of 120% or more, and a shore A hardness of 30 or more (measured according to standard ASTM D 2240), the silicone rubber 100 A sheath composition comprising 50 to 150 parts by weight of reinforcing agent, and 1 to 7 parts by weight of curing agent, based on parts by weight. The method of claim 1,
The silicone rubber is a sheath composition, characterized in that the main raw material is at least one silicone gum selected from the group consisting of methyl silicone, methylphenyl silicone, methylvinyl silicone, methylphenylvinyl silicone and fluorine silicone. The method of claim 2,
Sheath composition, characterized in that the viscosity of the silicone rubber is 10 million cps or more. The method according to any one of claims 1 to 3,
The reinforcing agent is a dry or wet silica that is surface-modified or not modified with one or more compounds selected from the group consisting of amines, epoxies, thiols, carboxylic acids, sulfonic acids, phosphoric acids, phosphines and cyanic acids, and the curing agent is benzoyl peroxide, alkyl-based. Sheath composition, characterized in that peroxide, dicumyl peroxide, or a combination thereof. The method of claim 4, wherein
The silica is 3-aminopropyltrimethoxysilane, N-2-aminoethyl-3-aminopropyltrimethoxysilane, 3-glydoxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3- Isocyanatopropyltrimethoxysilane, N- (beta-aminoethyl) gamma-aminopropyltrimethoxysilane, N- (beta-aminoethyl) gamma-aminopropylmethyldimethoxysilane, gamma-ureidopropyltrimeth A sheath composition, characterized in that the dry silica is oxysilane or a combination thereof. The method of claim 4, wherein
The curing agent is 2,4-dichlorobenzoyl peroxide, benzoyl peroxide, p-chlorobenzoyl peroxide, 2,5-dimethyl-2,5-di (tert-butylperoxy) hexane, di (tert-butyl ) Peroxide, dicumyl peroxide, tert-butyl cumyl peroxide, or a combination thereof, sheath composition. The method according to any one of claims 1 to 3,
A sheath composition, characterized in that it further comprises a heat-resistant improving agent, an anti-scorch agent, a flame retardant, a mold release agent, or a combination thereof.

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