KR20180077789A - Cable for a Ship Comprising Insulating Layer Having Thermostable Insulating Layer - Google Patents

Abstract

The present invention relates to a cable for a ship and, more particularly, to a cable for a ship including a conductor and an insulating layer surrounding the conductor. The maximum allowable temperature of the conductor is 120°C. The cross-section of the cable has a diameter of 1 to 2 mm. A weight per unit length of the cable is 8 to 12 g.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a cable for a ship including an insulation layer having improved heat resistance,

The present invention relates to a marine cable including an insulation layer having improved heat resistance.

Materials used for ships or marine cables are made of materials such as Ethylene Propylene Rubber (EPR) or Cross-Linked Polyethylene (XLPE) because they are used in special environments such as ships or the ocean.

These materials are specified by international standards, and the values specified by the conductor maximum permissible temperature or specification, which determines the permissible current, which is the most important feature in selecting a ship or marine cable, shall apply.

According to the IEC 60092-3 series, which is a representative international standard for ships or marine cables, the maximum permissible conductor temperature of EPR is specified as 90 ° C, and the permissible current is calculated. Based on the allowable current, .

Thus, the maximum permissible temperature of the conductor of the EPR insulator is specified to be 90 ° C due to the limitation of EPR manufacturing technology. However, as the heat resistance improvement technology of the polymer resin material has been developed in the recent years, researches on the development of the technology for increasing the maximum permissible temperature of the conductor have been continued.

For example, Korean Patent Laid-Open Publication No. 2012-0048520 (Patent Document 1) discloses an insulating composition such that the maximum allowable conductor temperature of the electric cable is 110 to 120 占 폚. The insulating composition is prepared to include an insulating composition comprising non-crosslinked polypropylene or reactive polypropylene and polypropylene. The insulation composition can improve the maximum permissible temperature of the conductor of the electric cable. However, since the stability of the polymer is degraded due to the external environment such as heat, oxygen, and light, the insulation composition can be decomposed and the polymer itself is not structurally stable. There may be degraded problems

Therefore, there is a continuing need for the development of marine cables having improved heat resistance and improved conductor maximum permissible temperature.

Korean Utility Model Publication No. 2012-0048520, "Insulating Composition and Electric Cable Including It,

As a result of various studies to solve the above problems, the inventors of the present invention found that a coating composition for forming an insulating layer included in a ship cable, Compatibilizers; Antioxidants; And EPDM (ethylene-propylene-non conjugated diene-terpolymer) copolymerized with a specific amount of ENB (ethylene norbornene) is used as the rubber resin, and two kinds of different oxidation It has been found that a cable for marine including an insulating layer formed using a cable covering composition prepared using an inhibitor has an improved heat resistance and an allowable conductor temperature of up to 120 캜.

Accordingly, it is an object of the present invention to provide a marine cable including an insulation layer having improved heat resistance.

In order to achieve the above object, the present invention provides a marine cable including a conductor and an insulating layer surrounding the conductor, wherein a maximum allowable temperature of the conductor is 120 캜, a diameter of the cable cross section is 1 to 2 mm, And the weight per unit length of the cable is 8 to 12 g / mm.

The marine cable may include a conductor, an insulating layer surrounding the conductor, and a sheath layer formed on the insulating layer.

Wherein the insulating layer comprises a rubber resin; Compatibilizers; Antioxidants; And an additive,

The rubber resin includes ethylene propylene rubber (EPR), ethylene-propylene-non conjugated diene terpolymer (EPDM) copolymerized with ethyleneorbornene (ENB) in an amount of 15 to 20% by weight and polyolefin-

The antioxidant may include two kinds of different antioxidants, that is, a first antioxidant for improving compatibility and a second antioxidant for improving the degree of crosslinking.

At this time, the EPDM may be one obtained by copolymerizing 45 to 55% by weight of ethylene, 30 to 40% by weight of propylene and 15 to 20% by weight of ENB.

Also, the cable covering composition preferably comprises 70 to 80 parts by weight of EPDM relative to 100 parts by weight of EPR; 40 to 60 parts by weight of POE; 5 to 15 parts by weight of compatibilizing agent; 10 to 20 parts by weight of a primary antioxidant; 4 to 8 parts by weight of a secondary antioxidant; And 8 to 13 parts by weight of an additive.

The present invention also relates to a method for producing a rubber composition, comprising the steps of: (S1) mixing ethylene propylene rubber (EPR), ethylene-propylene-non conjugated diene terpolymer (EPDM), polyolefin elastomer (POE), compatibilizing agent,

(S2) mixing the mixture prepared in the step (S1) with a secondary antioxidant; The present invention also provides a method for producing a cable covering composition.

Since the marine cable according to the present invention includes the insulating layer with enhanced heat resistance, the maximum permissible temperature of the conductor can be improved to 120 캜.

As the maximum allowable conductor temperature of the marine cable is improved, the thickness of the insulating layer included in the marine cable does not need to be increased, so that the diameter of the cable can be reduced and consequently the weight of the cable per unit length can be reduced .

1 is a cross-sectional view of a ship cable according to an embodiment of the present invention.

Hereinafter, the present invention will be described in detail in order to facilitate understanding of the present invention.

The terms and words used in the present specification and claims should not be construed in an ordinary or dictionary sense and the inventor can properly define the concept of the term to describe its invention in the best possible way It should be construed as meaning and concept consistent with the technical idea of the present invention.

Hereinafter, the present invention will be described in more detail with reference to the drawings.

1 is a cross-sectional view of a ship cable according to an embodiment of the present invention.

1, a cable for a ship according to the present invention may include a conductor 10, an insulation layer 20 formed on the conductor 10, and a sheath layer 30 formed on the insulation layer 20.

It can be seen that the marine cable has a maximum permissible conductor temperature according to IEC 60092-3 of 120 ° C and a maximum permissible conductor temperature which is higher than the conventional permissible conductor temperature of 90 ° C, thereby enhancing the heat resistance.

As the heat resistance of the marine cable is strengthened as described above, even if the thickness of the insulating layer 20 is thin, it is expected that the marine cable according to the present invention has a cross-sectional diameter of 1 to 2 mm , And the weight per unit length of the cable may be reduced to 8 to 12 g.

The sheath layer 30 may be formed of a material commonly used in the art as a sheath layer of a marine cable, for example, 12 to 33 wt% of vinyl acetate, 40 to 80 wt% of ethylene vinyl acetate, -propylene-non conjugated diene-terpolymer) in an amount of 1 to 40% by weight.

The insulating layer of the marine cable having the maximum permissible conductor temperature, diameter and weight as described above is composed of a rubber resin; Compatibilizers; Antioxidants; And an additive. ≪ IMAGE >

In the cable covering composition, the rubber resin may include ethylene propylene rubber (EPR), ethylene-propylene-non conjugated diene terpolymer (EPDM) copolymerized with ENB (ethylene norbornene) and polyolefin rubber The antioxidant includes two different kinds of antioxidants, and may include a primary antioxidant for improving compatibility and a secondary antioxidant for improving the degree of crosslinking.

Hereinafter, the cable covering composition used for forming the insulating layer of the marine cable according to the present invention will be described in more detail.

EPR (ethylene propylene rubber) is an amorphous polymer substance obtained by copolymerizing ethylene and propylene, and is an insulator generally used for high-voltage electric wires.

In the present invention, the EPR can be used as a base resin for preparing a cable covering composition.

Generally, EPDM is a copolymer of ethylene, propylene, and diene, and has ozone resistance, weather resistance, heat resistance, chemical resistance and electrical properties, and is useful for applications in harsh environments It is suitable as a material for forming a covering material of a ship or a marine cable.

The EPDM according to the present invention may be one obtained by copolymerizing ENB (ethylene norbornene) as a diene and copolymerizing 15 to 20% by weight of ENB. Specifically, the EPDM contains 45 to 55% by weight of ethylene, 30 to 40% % And ENB 15 to 20% by weight may be copolymerized.

The ENB may serve as a crosslinking point for vulcanization of the rubber resin. If the content of the ENB is less than 15% by weight, the crosslinking speed and the crosslinking density may be lowered, and the mechanical properties of the covering composition may be deteriorated. The crosslinking density of the rubber resin is excessively high, and the flexibility of the cable can be lowered. In addition, it is preferable that 15 to 20 wt% of ENB is copolymerized among the dienes so that EPDM can be produced even without a separate crosslinking agent.

The content of ethylene and propylene is set so that a polymer in the rubber phase can be formed. In particular, the amount of ethylene and propylene copolymerized with 15 to 20 wt% of the ENB is optimized to have chemically stable, to be. In other words, in the EPDM, it may not be possible to copolymerize EPDM if the above content ranges of ethylene, propylene and ENB are not satisfied at all, and the physical properties as a basic rubber resin for producing a cable covering composition, Heat resistance, insulation, mechanical properties, flexibility and the like may be lowered.

In the cable covering composition of the present invention, the content of the EPDM may be 70 to 80 parts by weight based on 100 parts by weight of the EPR. When the EPDM is less than 70 parts by weight, the tensile strength and elongation of the cable covering composition may be lowered If the amount is more than 80 parts by weight, the content of EPDM is relatively increased as compared with other components including EPR, POE, antioxidant and additives, and the heat resistance is lowered.

In the present invention, in order to enhance the heat resistance by improving the compatibility of the components contained in the cable coating composition, the EPDM has a glass transition temperature (Tg) of -55 to -45 캜, an elastic modulus of 205 to 215 g / EPDM having a Mooney viscosity (ML _{1 + 4} , 100 ° C) of 23 to 25 is preferably used. If EPDM does not satisfy any of the above specified glass transition temperature, modulus of elasticity and Mooney viscosity, the compatibility of the cable cladding composition can not be expected because the compatibility is not good. As a result, It can be difficult to do. The Mooney viscosity may be measured according to ASTM D1646.

In the present invention, POE is a rubber resin having a stable structure as compared with EPR and EPDM, and is superior in heat resistance, so that a cable covering composition having improved heat resistance can be prepared by mixing POE with EPR and EPDM.

The POE content may be 40 to 60 parts by weight based on 100 parts by weight of the EPR. If the POE is less than 40 parts by weight, the heat resistance of the cable covering composition may not be improved. If the amount is more than 60 parts by weight, Relative to other components, the tensile strength and elongation of the cable covering composition may be lowered.

In the present invention, in order to enhance the heat resistance through improvement of the structural stability of the cable covering composition, POE has a glass transition temperature (Tg) of -65 to -50 캜, an elastic modulus of 220 to 230 g / _{1 + 4} , 100 ° C) of 31 to 33 is preferably used. If POE does not satisfy at least one of the above specified glass transition temperature, modulus of elasticity and Mooney viscosity, it can not be expected that the compatibility of the cable coating composition is improved and the effect of improving the heat resistance of the cable covering composition can not be expected. It can be difficult to do.

In order for POE according to the present invention to have a glass transition temperature, an elastic modulus and a Mooney viscosity as described above, the polyolefin may be a copolymer of ethylene and an? -Olefin.

The? -Olefin-based monomer used in the present invention may be a C ₃ to C ₂₀ linear or branched? -Olefin-based compound (or an alkene compound), preferably an olefin-based compound of C ₅ to C ₁₈ Preferably a linear olefinic compound, most preferably a linear alpha-olefinic compound.

Examples of the olefinic monomer include ethylene (or ethene), propylene (or propene), 1-butene, 1-pentene, 1-hexene, 1-heptene, Linear alpha-olefins such as dodecene, 1-tetradecene, 1-hexadecene and 1-aidocene, isobutylene, 3-methyl-1-butene, Branched alpha-olefins such as butene, 4-methyl-1-butene, 3-methyl-1-pentene, 4-methyl- Can be used alone or in combination, and more preferably, linear alpha olefins can be used.

The above-mentioned? -Olefin monomers are more flexible than branched? -Olefins and have excellent flowability and structural penetration ability when linear? -Olefins are used, thus securing high compatibility with polyolefin-based substrates. And is suitable as a raw material for a cable covering composition. Here, the? -Olefin monomer may be one kind of the above-mentioned monomers or two or more kinds of monomers, and is not particularly limited in the present invention.

In the present invention, the compatibilizing agent can improve the heat resistance of the cable covering composition by improving the compatibility.

Particularly, in order to enhance the heat resistance by improving the compatibility of the cable covering composition, the compatibilizer is a maleic anhydride modified polymer, and the polymer is a styrene polymer, an ethylene polymer, a butadiene polymer, a propylene polymer A polymer, a copolymer thereof, and a mixture thereof. For example, the compatibilizing agent may be selected from the group consisting of maleic anhydride-styrene-ethylene-butadiene-styrene (SEBS-g-MA), styrene-ethylene-butadiene-styrene (SEBS), maleic anhydride polypropylene And ethylene-propylene-diene-ethylene-ethylene-propylene-diene-monomer (EPDM-g-MA).

In the cable covering composition of the present invention, the content of the compatibilizing agent may be 5 to 15 parts by weight based on 100 parts by weight of the EPR. If the amount of the compatibilizing agent is less than 5 parts by weight, the compatibility of the cable covering composition may deteriorate If the amount is more than 15 parts by weight, the content of the compatibilizing agent becomes relatively larger than that of the other components, resulting in deterioration of physical properties such as tensile strength and elongation.

The cable covering composition according to the present invention comprises a first antioxidant for improving compatibility and a second antioxidant for improving the degree of crosslinking, wherein two different kinds of antioxidants are included, Heat resistance can be improved.

The primary antioxidant not only improves the compatibility but also can protect the rubber resin from external environment including heat, oxygen and light.

The primary antioxidant may be at least one selected from the group consisting of an amine-based antioxidant, a phenol-based antioxidant, and a quinoline-based antioxidant.

The amine antioxidant may be selected from the group consisting of p-phenylene diamine, diphenyl amine and acetone, diphenylamine and diisobutylene, and 4,4'-bis (Alpha, alphadimethylbenzyl) diphenylamine), and the phenol-based antioxidant may be at least one selected from the group consisting of 2,2'-thiodiethylbis (3,5-di-tert-butyl-4-hydroxyphenyl) -propionate] (2,2'-thiodiethylbis- [3- propionate] and tetrakis [methylene 3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] methane (tetrakis methylene 3- (3,5- -hydroxyphenyl) propionate] methane), and the quinoline antioxidant may be at least one selected from the group consisting of poly (1,2-dihydro-2,2,4-trimethylquinoline) -2,2,4-trimethylquinoline).

The secondary antioxidant not only improves the degree of crosslinking but also acts to decompose and remove the product formed due to the structural instability of the rubber resin.

The secondary antioxidant may be one or more selected from the group consisting of a phosphite-based antioxidant, a benzimidazole-based antioxidant, and a thioester-based antioxidant.

Wherein the phosphite-based antioxidant is triphenyl phosphite, the benzimidazole-based antioxidant is 2-mercaptobenzimidazole, the thioester-based antioxidant is distearyl 3 , Distearyl 3,3-thiodipropionate.

By using the primary and secondary antioxidants, which are different antioxidants, as described above, the present invention can achieve improvement in heat resistance through compatibility, degree of crosslinking, and structural stability. In order to maximize the effect of improving the heat resistance The content of the primary and secondary antioxidants can be optimized.

The content of the primary antioxidant may be 10 to 20 parts by weight based on 100 parts by weight of the EPR. When the content of the primary antioxidant is less than 10 parts by weight, the rubber resin becomes unstable due to the external environment, If the amount is more than 20 parts by weight, the content of the first-order antioxidant may be relatively increased, thereby deteriorating physical properties such as tensile strength and elongation.

The content of the second antioxidant may be 8 to 13 parts by weight based on 100 parts by weight of EPR. If the content of the second antioxidant is less than 8 parts by weight, the degree of crosslinking may be lowered and the polymer may become unstable due to the external environment If the amount is more than 13 parts by weight, the content of the secondary antioxidant becomes relatively large, and properties such as tensile strength and elongation can be lowered.

The cable covering composition according to the present invention may further comprise at least one additive selected from the group consisting of a flame retardant, a filler, and a reinforcing agent for reinforcement of various properties other than heat resistance.

The additive may be surface-coated to improve compatibility, and may be surface-coated with at least one selected from the group consisting of stearic acid, vinyl based silane, and mixtures thereof .

The content of the additive may be 8 to 13 parts by weight based on 100 parts by weight of the EPR. If the amount of the additive is less than 8 parts by weight, the effect of improving the flame retardancy and mechanical strength may be insignificant. , The content of the additive becomes relatively large, and properties such as tensile strength and elongation can be lowered.

The flame retardant is for improving the flame retardancy, and the flame retardancy of the cable cover composition can be improved by simply adding and mixing the flame retardant into the cable cover composition or chemically reacting with the EPR, EPDM and POE to introduce flame retardant into the molecule .

The flame retardant may be a non-halogen flame retardant in consideration of environmental friendliness. The non-halogen flame retardant may be classified into a non-halogen type inorganic flame retardant and a non-halogen type organic flame retardant.

Wherein the non-halogen based inorganic flame retardant is at least one hydrated metal compound selected from the group consisting of Al (OH) ₃ , Mg (OH) ₃ and calcium aluminate; And at least one phosphorus compound selected from the group consisting of APP (Ammonium Polyphosphate); At least one nitrogen-based compound selected from the group consisting of ammonium phosphate and ammonium carbonate; Molybdenum compounds; Zinc borate; And zinc stannate; or one or more selected from the group consisting of zinc stearate and zinc stearate.

The filler may serve to improve mechanical properties such as impact resistance of the heat-resistant insulating composition, and may be any conventional organic filler or inorganic filler. However, at least one filler selected from the group consisting of talc and calcium carbonate may be used have.

The reinforcing agent may serve to improve mechanical properties such as strength, and the reinforcing agent may be a clay.

The cable covering composition according to the present invention has a maximum allowable conductor temperature of 120 캜, a volume resistivity of 2 x 10 ¹⁵ to 2 x 10 ¹² (Ω · cm), a capacitance change rate of 5 to 15% The rate of change of the tensile strength and the rate of change of the elongation percentage measured by the above method may be 30% or less, respectively.

The maximum permissible conductor temperature of the cable covering composition is 120 ° C., as described above, by selecting EPR, 15-20 wt% ENB copolymerized EPDM and different types of primary and secondary antioxidants as described above, Weight range. ≪ / RTI > Further, the rubber having a specific physical property such as a glass transition temperature, an elastic modulus and a Mooney viscosity of the POE rubber can be selected and used as a rubber resin to further improve the heat resistance improving effect.

As the conductor maximum allowable temperature is improved up to 120 ° C, the cable made of the cable covering composition exhibits excellent heat resistance and insulation even with a thin covering material, so that the diameter of the cable, that is, the cross-sectional area can be reduced, Weight per unit can also be reduced.

The present invention also relates to a method for producing a cable covering composition as described above, wherein said cable covering composition comprises (S1) ethylene propylene rubber (EPR), ethylene-propylene-non conjugated diene terpolymer (EPDM) a polyolefin elastomer, a compatibilizing agent, an additive, and a primary antioxidant; And

(S2) mixing the mixture prepared in the step (S1) with a secondary antioxidant.

The weight and kind of each component used in the method for producing the cable covering composition are as described above.

In the method for producing the cable covering composition according to the present invention, the antioxidant may be classified into a primary antioxidant and a secondary antioxidant depending on its function. The primary antioxidant may improve compatibility, Oxygen and light, and the second antioxidant may serve to improve the degree of crosslinking and to decompose the resulting product due to instability due to the external environment.

Due to the different functions of such primary and secondary antioxidants, it is possible to mix the primary antioxidant first and then mix the secondary antioxidant later.

In the step (S1), the primary antioxidant may be first mixed with a resin such as EPR, EPDM and POE to uniformly mix these resins and protect them from external environments including heat, oxygen and light.

In the step (S2), the product produced due to the instability due to the external environment including heat, oxygen and light, in spite of the structural instability of the resin such as EPR, EPDM or the primary antioxidant mixture, A secondary antioxidant can be mixed to decompose.

If the secondary antioxidant is first mixed in the step (S1) and then the primary antioxidant is mixed later in the step (S2), the degree of crosslinking between the rubber resins may be lowered and the rubber resin may be removed from the external environment The resin can not be protected and the unstable state of the resin due to the external environment is maintained. Therefore, the product produced from the resin may be increased due to such an unstable state. Therefore, there may be a limit in decomposing such a large amount of the produced product using the second antioxidant in the step (S1).

Further, when the primary and secondary antioxidants are mixed together in the step (S1), the functionality of each of the primary and secondary antioxidants is lowered, and the role of protecting the resin from the external environment and the continuation of the unstable state It is impossible to properly perform the function of decomposing the product generated from the resin, so that the insulation and heat resistance effect by EPR, EPDM and POE may be insignificant. The same result may be obtained when the primary and secondary antioxidants are mixed together in the step (S2).

Therefore, in the method for producing a coating composition for a cable according to the present invention, it is preferable that the primary antioxidant and the secondary antioxidant are mixed respectively, and in order to maximize their function, To protect the resin from the external environment, and then to mix the secondary antioxidant later to improve the degree of crosslinking and to decompose some of the products produced from the resin.

The coating composition for cable thus produced not only improves the heat resistance but also has excellent mechanical properties such as volume resistance, tensile strength and elongation, and can be used as a covering material for ships or marine cables used in harsh environments such as the oceans .

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope and spirit of the invention as disclosed in the accompanying claims. Changes and modifications may fall within the scope of the appended claims.

In the following Examples and Comparative Examples, a cable covering composition was prepared according to the composition and antioxidant mixing sequence as shown in Table 1 below.

Unit: parts by weight Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 EPR 100 100 100 100 100 100 100 EPDM 75 75 75 75 75 75 75 POE 50 50 50 50 50 50 50 Compatibilizer SEBS-g-MA 10 10 10 10 10 10 10 additive
(Flame retardant) Al (OH) ₃ 10 10 10 10 10 10 10 Primary antioxidant p-phenylenediamine 15 15 15 15 15 15 15 Secondary antioxidant Triphenylphosphite 10 10 10 10 10 10 10 Copolymerized with EPDM
ENB content 18 wt% 15
weight% 20
weight% 13
weight% 22
weight% 18
weight% 18
weight% Primary and secondary antioxidant mixing sequence Primary
→ Secondary Primary
→ Secondary Primary
→ Secondary Primary
→ Secondary Primary
→ Secondary Primary and secondary simultaneous Secondary
→ Primary

Example  1: Preparation of Cable Covering Composition

One- 1.EPR , EPDM , POE, compatibilizer, primary antioxidant and additive mixture

EPR 100 parts by weight, EPR 100 parts by weight, EPDM 75 parts by weight, POE 50 parts by weight, 10 parts by weight of maleic anhydride styrene-ethylene-butadiene-styrene (SEBS-g-MA) 15 parts by weight of p-phenylenediamine and 10 parts by weight of Al (OH) ₃ , which is a non-halogen flame retardant, as an additive.

At this time, the EPDM is obtained by copolymerizing 49 wt% of ethylene, 33 wt% of propylene, and 18 wt% of ENB.

1-2.2 Antioxidant Mixing

10 parts by weight of triphenylphosphite as a secondary antioxidant was mixed with the mixture obtained in the above 1-1 to prepare a cable coating composition.

Example  2: EPDM Copolymerized Of ENB  Manufacture of cable coating composition with different contents

A cable coating composition was prepared in the same manner as in Example 1 except that EPDM copolymerized with 51 wt% of ethylene, 34 wt% of propylene and 15 wt% of ENB was used.

Example  3: EPDM Copolymerized Of ENB  Manufacture of cable coating composition with different contents

A cable coating composition was prepared in the same manner as in Example 1 except that EPDM copolymerized with 47 wt% of ethylene, 36 wt% of propylene and 20 wt% of ENB was used.

Comparative Example  One: EPDM Copolymerized Of ENB  Manufacture of cable coating composition with different contents

A cable coating composition was prepared using EPDM copolymerized with 52 wt% of ethylene, 35 wt% of propylene and 13 wt% of ENB in the same manner as in Example 1.

Comparative Example  2: EPDM Copolymerized Of ENB  Manufacture of cable coating composition with different contents

A cable coating composition was prepared using EPDM copolymerized with 44 wt% of ethylene, 34 wt% of propylene and 22 wt% of ENB in the same manner as in Example 1.

Comparative Example 3: Primary  Manufacture of Cable Covering Composition without Antioxidant

The procedure of Example 1 was followed except that the primary and secondary antioxidants were simultaneously mixed to prepare a cable coating composition. That is, the cable covering composition was prepared without mixing steps 1 and 2 by mixing the primary and secondary antioxidants together in step 1-1.

Comparative Example 4: Secondary  Manufacture of Cable Covering Composition without Antioxidant

The procedure of Example 1 was followed except that the order of mixing the primary and secondary antioxidants was changed and mixed to prepare a cable covering composition. That is, a secondary antioxidant was mixed in place of the primary antioxidant in the above-mentioned Step 1-1, and a primary antioxidant was mixed in the above Step 2-1 instead of the secondary antioxidant to prepare a cable covering composition.

Experimental Example  1: Property evaluation of cable cover composition

The volume resistivity, the change rate of the electrostatic capacity, the change rate of the tensile strength and the rate of change of the elongation percentage of the cable cover composition prepared in Examples and Comparative Examples were measured in the following manner.

At this time, the coating composition for cables prepared in Examples and Comparative Examples was kneaded in an open roll at 110 DEG C, and then molded in a press at 170 DEG C for 20 minutes to prepare a specimen.

(1) Volume resistivity

The volume resistivity was measured according to IEC 60092-350. The volume resistance was calculated using the measured insulation resistance after applying a voltage of 100 V for 3 minutes at 20 ° C to the specimen. When the volume resistivity according to IEC 60092-350 is 2 x 10 ¹² to 2 x 10 ¹⁵ (Ω · cm), it means that it has heat resistance suitable as a ship or marine cable covering composition.

(2) Capacitance change rate

IEC 60092-350, a 4.5 m insulated specimen was prepared and dried in an oven at 73 ° C. for 24 hours and then immersed in water heated to 50 ° C. for 14 days, And 14 days, respectively, and the rate of change was measured. The smaller the measured change rate, specifically 5 to 15%, means that the insulating property and the heat resistance are excellent.

(3) Tensile strength change rate

The tensile strength was measured at 250 mm / min according to IEC 60811-501, and the rate of change in tensile strength was calculated using the measured value at room temperature and the measured value after aging at 170 ° C for 169 hours . The smaller the rate of change in the calculated tensile strength, the better the heat resistance and the mechanical properties.

(4) Elongation rate change rate

The elongation percentage change rate was calculated in the same manner as the tensile strength according to IEC 60811-401. The smaller the calculated elongation percentage change rate, the better the heat resistance.

Volume resistance Capacitance change rate Tensile strength change rate Elongation rate
Rate of change Ω · cm % % % Example 1 2 x 10 ¹³ 7 15 8 Example 2 3 x 10 ¹² 8 18 12 Example 3 4 x 10 ¹³ 8 21 14 Comparative Example 1 5 x 10 ¹⁸ 20 33 31 Comparative Example 2 3 x 10 ¹⁶ 24 35 36 Comparative Example 3 4 x 10 ¹⁶ 21 40 34 Comparative Example 4 3 x 10 ¹⁷ 22 38 33

As shown in Table 2, the specimens prepared from the cable coating composition of Examples 1 to 3 had smaller volume resistivities than Comparative Examples 1 to 4, and were also excellent in heat resistance due to small capacitance change, tensile strength and rate of change in elongation percentage .

In particular, Comparative Examples 1 and 2 show that the content of ENB copolymerized in EPDM is smaller or larger than that in Examples, and the volume resistance becomes excessively large.

Comparative Example 3 was a mixture of primary and secondary antioxidants simultaneously. In Comparative Example 4, the secondary antioxidant was mixed first and then the primary antioxidant was mixed. As a result, the volume resistance was increased and the capacitance , The tensile strength and the elongation percentage change rate are also excessively large, and the heat resistance is poor.

Experimental Example  2: Maximum allowable conductor temperature of ship cable, diameter  And weighing

After forming the insulating layer of the marine cable including the conductor, the insulating layer and the sheath layer using the cable covering composition prepared in the examples and the comparative examples, the cable for the cable maximum permissible temperature, the cable diameter and the cable length per unit length of the marine cable The weight was measured. At this time, the sheath layer may be formed by a composition comprising 20% by weight of vinyl acetate, 60% by weight of ethylene vinyl acetate and 20% by weight of EPDM. The above-mentioned marine cables can be produced by a conventional extrusion method in the art.

At this time, the maximum permissible temperature of conductor is measured according to IEC 60092-3.

Maximum Allowable Conductor Temperature Cable diameter Cable weight per unit length ℃ mm g Example 1 120 1.11 9 Example 2 120 1.29 12 Example 3 120 1.21 14 Comparative Example 1 98 2.55 32 Comparative Example 2 101 3.01 37 Comparative Example 3 95 2.68 46 Comparative Example 4 97 2.88 44

As shown in Table 3, in the case of Examples 1 to 3, the maximum permissible temperature of the conductor was 120 ° C., whereas the maximum permissible conductors of Comparative Examples 1 to 4 were lower than those of the examples.

In addition, the cable diameter and the weight per unit length were also significantly lower than those of Comparative Examples 1 to 4 in Examples 1 to 3, indicating that a cable covering composition and cable excellent in heat resistance can be produced.

10: Conductor
20: Insulation layer
30: Sheath layer

Claims (12)

A cable for a ship comprising a conductor and an insulating layer surrounding the conductor,
Wherein the conductor has a maximum allowable temperature of 120 DEG C, a diameter of the cable cross-section of 1 to 2 mm, and a weight per unit length of the cable of 8 to 12 g / mm. The method according to claim 1,
And a sheath layer formed on the insulating layer. The method according to claim 1,
Wherein the insulating layer comprises a rubber resin; Compatibilizers; Antioxidants; And an additive,
The rubber resin includes EPDM (ethylene-propylene-non conjugated diene-terpolymer) and polyolefin elastomer (POE) copolymerized with ethylene propylene rubber (EPR), ethylene norbornene (ENB)
Wherein the antioxidant comprises two different kinds of antioxidants, the first antioxidant for improving compatibility and the second antioxidant for improving the degree of crosslinking. The method of claim 3,
Wherein said EPDM is copolymerized with 45 to 55% by weight of ethylene, 30 to 40% by weight of propylene and 15 to 20% by weight of ENB. The method of claim 3,
70 to 80 parts by weight of EPDM relative to 100 parts by weight of EPR; 40 to 60 parts by weight of POE; 5 to 15 parts by weight of compatibilizing agent; 10 to 20 parts by weight of a primary antioxidant; 4 to 8 parts by weight of a secondary antioxidant; And 8 to 13 parts by weight of an additive. The method of claim 3,
Wherein the EPR has a glass transition temperature (Tg) of -50 to -30 占 폚, an elastic modulus of 190 to 200 g / d and a Mooney viscosity (ML _{1 + 4} , 100) of 26 to 29. The method of claim 3,
Wherein the EPDM has a glass transition temperature (Tg) of -55 to -45 캜, an elastic modulus of 205 to 215 g / d, and a Mooney viscosity (ML _{1 + 4} , 100 캜) of 23 to 25 . The method of claim 3,
Wherein the POE has a glass transition temperature (Tg) of -65 to -50, an elastic modulus of 220 to 230 g / d, and a Mooney viscosity (ML _{1 + 4} , 100 캜) of 31 to 33. The method of claim 3,
Wherein the compatibilizer is one selected from the group consisting of a styrene polymer modified with maleic anhydride, an ethylene polymer, a butadiene polymer, a propylene polymer, a copolymer thereof, and a mixture thereof. cable. The method of claim 3,
Wherein the primary antioxidant is at least one selected from the group consisting of an amine antioxidant, a phenol antioxidant, and a quinoline antioxidant. The method of claim 3,
Wherein the secondary antioxidant is at least one selected from the group consisting of a phosphite antioxidant, a benzimidazole antioxidant, and a thioester antioxidant. The method of claim 3,
Wherein the additive is at least one selected from the group consisting of a flame retardant, a filler, and a reinforcing agent.

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