KR20210131257A - Composition for floating solar cable sheath and floating solar cable including cable sheath manufactured thereof - Google Patents

Abstract

The present invention relates to a composition for a floating solar cable sheath and a floating solar cable including a cable sheath prepared therefrom. The composition for a floating solar cable sheath and the floating solar cable including a cable sheath prepared therefrom can satisfy all of the physical properties required in the international standard (IEC 62930), which are necessary for cable use, and can additionally satisfy various environmental characteristics at the same time.

Description

Composition for a water solar cable sheath and a water solar cable comprising a cable sheath manufactured therefrom

The present invention relates to a composition for a waterborne solar cable sheath and a waterborne solar cable comprising the cable sheath prepared therefrom. More specifically, the present invention provides a composition for a water-based solar cable sheath that can satisfy various environmental resistance properties so that it can be utilized for a water-based solar cable purpose at the same time as physical properties to meet the standard as a cable (IEC 62930), and from this It relates to a floating solar cable comprising the manufactured cable sheath.

In general, the types of power generation devices that generate power can be divided according to the energy source used, and representatively, thermal power generation using fossil fuels such as petroleum or coal, and power generation using solar power, nuclear power, hydro power, tidal power, and wind power etc.

Among these power generation devices, nuclear power generation devices have the advantage of being able to generate electricity at a lower cost compared to thermal power generation, but there are many reports of environmental pollution and human harm caused by radiation, and installation is limited due to opposition from local residents. is made with Moreover, facility investment is not being made smoothly due to the risk of the recent Fukushima nuclear accident in Japan and the problem of disposal of nuclear waste generated after electricity is generated by nuclear power generation.

In addition, in the case of thermal power generation, fossil fuels such as coal or petroleum are used, and when electricity is generated from these fuels for power generation, there is a problem that not only pollutes the environment but also the cost of fossil fuels is high. Recently, oil prices are rising due to a decrease in resource reserves, such as fossil fuels, and the cost of power generation is increasing accordingly. .

In addition, since regulations to suppress the emission of carbon dioxide are being implemented around the world in recent years, the development of a new power generation device that does not emit carbon dioxide is required.

In the meantime, the rapid growth of solar power generation has been achieved due to the government's policy support, but the reality is that environmental problems that go against the concept of eco-friendly energy sources possessed by new and renewable energy sources are also emerging. Solar power generation is an inevitable choice in a country that is highly dependent on fossil fuels, such as Korea. However, due to the nature of the area-intensive photovoltaic power generation industry, large-capacity photovoltaic power plants are mainly installed in forests or farmlands where land costs are relatively low, which has been pointed out as an environmental and social problem due to damage to forests and landscapes.

Meanwhile, until now, solar power generation technology has mainly focused on research to increase the efficiency of solar modules, and as a result, the cost of solar power generation becomes the same as that of fossil fuels in the near future. We are achieving what we can expect to achieve. However, considering the reality of a narrow land and the characteristics of solar power generation, which is an area-intensive industry, it is difficult to build a large-scale power plant on the ground. Floating photovoltaic power generation is attracting attention based on the fact that it has a power generation efficiency of about 10% or more higher than that of actual terrestrial photovoltaic power generation.

The Floating Photovoltaic Power Plant system is a new concept power generation method that combines the existing terrestrial photovoltaic power generation technology and floating technology on the water surface.

1 is a conceptual diagram for a floating solar power generation system.

1, the structure 11 supporting the photovoltaic module 10 is supported by the buoyancy agent 12 to float the photovoltaic module 10 on the water, and an anchor 13 and a weight ( 14), etc., are connected to the structure 11 so that they are fixed regardless of water level fluctuations, and, like solar power generation on the ground, the power generated from the solar module 10 can be transferred to the underwater cable 100. It is transmitted to the electric room 15 on the ground through, and the electric power transmitted to the electric room 15 has a structure in which the electric power is moved or distributed through the KEPCO pole 16 .

Although the structure of the power cable may be slightly different depending on the application, a general structure of the power cable includes a conductor 20 and an insulating layer 21 surrounding the conductor 20 at the center.

In particular, the underwater cable used to transmit the power generated from the solar module to the electrical room on the ground, unlike the power cable generally used on the ground, has to be installed underwater, so the sheath layer formed on the outermost part of the underwater cable is It should be formed of a material with excellent water resistance. Therefore, a high-density polyethylene (HDPE) material satisfying such water resistance was used as a sheath to protect internal insulation and structures from moisture. In addition, as floating photovoltaic power generation facilities are installed in reservoirs and freshwater lakes, a proven material that does not pollute the water quality even when exposed to water for a long time was used as the cable sheath (dissolution test, sanitary and safety rules/waterworks Act Article 14).

However, it only satisfies the minimum conditions that can be used for the award, and in addition, the cable is vulnerable to various environmental resistance properties that can be exposed, such as UV, heat resistance and cold resistance. In particular, in the case of a sheath, there is a weak problem in terms of heat resistance and lifespan by using non-crosslinked polyethylene.

Patent Document 1 discloses a sheath composition for an electric wire for improving physical properties such as flexibility as a technique proposed to solve the above problems.

More specifically, the technology disclosed in Patent Document 1 is, (a) a thermoplastic polyurethane (TPU) having a melt index (MI) of 30 to 50 g/10 min 50 to 90 phr; (b) 10 to 50 phr of a styrenic thermoplastic elastomer having a melt index (MI) of 1 to 5 g/10 min; (c) 10 to 70 phr of phosphorus-based flame retardants; (d) 1 to 10 phr of a flame retardant aid; (e) 0.1 to 5 phr of antioxidant; (f) UV absorbers and stabilizers 0.1 to 5 phr; And (g) relates to a sheath composition for an electric wire comprising a lubricant 0.1 to 5phr.

However, in the case of the technology disclosed in Patent Document 1, not only cannot satisfy the tensile strength and elongation, which are physical properties required according to the required standards when applied as a sheath of an underwater cable, but also use a thermoplastic polyurethane resin as a base resin, Since the polymer of the ester or ether group and the polyol group of the thermoplastic polyurethane resin is very vulnerable to hydrolysis, there is a problem in that water resistance is very poor. Moreover, in order to increase compatibility between the mixed resins, a manufacturing method including an extrusion process through two screw mixing must be used.

Therefore, there is an urgent need to develop a technology for a floating solar cable that satisfies the physical properties required according to the required standard of the cable and at the same time satisfies various environmental resistance characteristics.

Patent Document 1: Korean Patent Publication No. 10-2017-0128024

In order to solve the problems of the prior art, the present inventors satisfy the physical properties required according to IEC 62930, a standard of the International Electrotechnical Commission (IEC) required for application as a sheath of a cable, and at the same time, various environmental resistance characteristics To provide a water-based solar cable comprising a composition for a water-based solar cable sheath satisfying the and a cable sheath prepared therefrom.

As a means for solving the above technical problem,

The present invention, ethylene vinyl acetate (EVA) resin; and a polyolefin resin grafted with a polar moiety as a base resin, and based on 100 parts by weight of the base resin, 80 to 153 parts by weight of a flame retardant. The composition for a solar cable sheath provides a composition for a water-based solar cable sheath that satisfies the following Equations 1 to 3.

[Formula 1]

A ≤ 40 (unit: %)

[Formula 2]

-15 ≤ ㅿTS ≤ 15 (Unit: %)

[Equation 3]

-20 ≤ ㅿE ≤ 20 (Unit: %)

In Equation 1, A is a dumbbell specimen prepared according to the IEC 60811-511 standard for a sheath separated from a water photovoltaic cable including a sheath layer prepared from the composition for a water photovoltaic cable sheath under 50% RH humidity. It refers to the rate of change of the mass of the dumbbell specimen measured after storage and pretreatment for 7 days, and then taking out the dumbbell specimen after maintaining immersion in a water bath at 50° C. for 100 days compared to the mass of the measured dumbbell specimen, in Equation 2, ㅿTS is The sheath separated from the water photovoltaic cable including the sheath layer prepared from the composition for the water photovoltaic cable sheath was pretreated by storing the dumbbell specimen prepared according to the IEC 60811-511 standard for 7 days under 50% RH humidity, It means the rate of change of tensile strength (ㅿTS100 - ㅿTS28 / ㅿTS28) measured after maintaining the immersion of the dumbbell specimen in a water bath at 50 ° C for 28 days (ㅿTS28) and 100 days (ㅿTS100), respectively, and the above formula In 3, ㅿE is a dumbbell specimen prepared according to the IEC 60811-511 standard for a sheath separated from a water photovoltaic cable including a sheath layer prepared from the composition for a water photovoltaic cable sheath, under 50%RH humidity for 7 days. After storage and pretreatment, the rate of change in elongation measured after maintaining the immersion in the dumbbell specimen for 28 days (ㅿE28) and 100 days (ㅿE100) in a water bath at 50°C (ㅿE100 - ㅿE28 / ㅿE28) it means.

In addition, the present invention, the base resin, 70 parts by weight to 90 parts by weight of ethylene vinyl acetate (EVA) resin; And 10 parts by weight to 30 parts by weight of a polar moiety grafted polyolefin resin; it provides a composition for a water-based solar cable sheath comprising a.

In addition, the present invention, the flame retardant, based on 100 parts by weight of the base resin, 80 parts by weight to 150 parts by weight of an inorganic metal-based flame retardant; And 0.5 parts by weight to 3 parts by weight of phosphorus-based flame retardant; provides a composition for a water-based solar cable sheath comprising a.

In addition, the present invention provides a composition for a water photovoltaic cable sheath, characterized in that the composition for a water photovoltaic cable sheath satisfies the following formula (4).

[Equation 4]

X ≥ 30 (unit: %)

In Equation 4, X is a dumbbell specimen prepared according to IEC 60811-501 standard for a sheath separated from a water photovoltaic cable including a sheath layer prepared from the composition for a water photovoltaic cable sheath, tension installed inside the low temperature chamber It means the low-temperature elongation measured at a tensile rate of 25±5 mm/min using a test facility.

In addition, the present invention, the melting temperature (T _m ) of the polyolefin resin grafted with the polar moiety is characterized in that 50 ℃ to 90 ℃, provides a composition for a water-borne solar cable sheath.

In addition, the present invention, the polyolefin resin grafted with the polar moiety is ethylene vinyl acetate grafted with maleic anhydride, it provides a composition for a waterborne solar cable sheath.

In addition, the present invention, the composition for the photovoltaic cable sheath, with respect to 100 parts by weight of the base resin, 5 parts by weight to 20 parts by weight of an antioxidant; And 5 to 10 parts by weight of UV stabilizer or carbon black; provides a composition for a water-based solar cable sheath, characterized in that it additionally comprises.

In addition, the present invention provides a composition for a water photovoltaic cable sheath, characterized in that the composition for a water photovoltaic cable sheath satisfies all of the following Equations 5 to 7.

[Equation 5]

X ≥ 30 (unit: %)

[Equation 6]

Y ₁ ≥ 70 (unit: %)

[Equation 7]

Y ₂ ≥ 70 (unit: %)

In Equation 5, X is a dumbbell specimen prepared in accordance with IEC 60811-511 standards for a sheath separated from a water photovoltaic cable including a sheath layer prepared from the composition for a water photovoltaic cable sheath, tension installed inside a low temperature chamber It means a low-temperature elongation rate measured at a tensile rate of 25±5 mm/min using a test facility, and in Equation 6, Y ₁ is waterborne sunlight including a sheath layer prepared from the composition for the water-borne solar cable sheath. Dumbbell specimens prepared according to IEC 60811-501 standards of the sheath separated from the cables are put in a weathering test facility, exposed for 720 hours, and then taken out, and then the specimens are stored at 25±5℃, 50%RH for 18 hours, It means the residual tensile strength versus the tensile strength during the weather resistance/UV test measured at a tensile rate of 25±5 mm/min using a tensile test facility, and in Equation 7, Y ₂ is prepared from the composition for the water-borne solar cable sheath Dumbbell specimens prepared according to IEC 60811-501 standards of the sheath separated from the floating solar cable including the sheath layer were put in a weathering test facility, exposed for 720 hours, and then taken out, and the specimens were removed at 25±5℃, 50 It means the residual elongation compared to the elongation during the weather resistance/UV test measured at a tensile rate of 25±5 mm/min using a tensile test facility after storage at %RH for 18 hours.

In addition, the present invention provides a composition for a water photovoltaic cable sheath, characterized in that the composition for a water photovoltaic cable sheath satisfies both Equations 8 and 9 below.

[Equation 8]

Z ≥ 0.816 (Unit: kgf/mm ² )

[Equation 9]

T ≥ 120 (unit: ℃)

In Equation 8, Z is a dumbbell specimen prepared according to the IEC 60811-501 standard for a sheath separated from a water-based solar cable including a sheath layer prepared from the composition for a water-based solar cable sheath Extrusion and cross-linking process 16 hours Thereafter, it means the tensile strength among non-aging properties measured at a tensile rate of 250±50 mm/min using a tensile test facility, and in Equation 9, T is a sheath layer prepared from the composition for a water-based solar cable sheath. It means the Temperature Index calculated by selecting the end-point as 50% elongation based on IEC 60216-1 and IEC 62930 for a dumbbell specimen manufactured according to IEC 60811-511 standard of a sheath separated from a floating solar cable containing do.

In addition, the present invention, the composition for the water photovoltaic cable sheath, with respect to 100 parts by weight of the base resin, 2 parts by weight to 10 parts by weight of a crosslinking agent; And 0.5 parts by weight to 3 parts by weight of a crosslinking aid is provided, it characterized in that it further comprises, it provides a composition for a water-based photovoltaic cable sheath.

In addition, the present invention provides a composition for a water photovoltaic cable sheath, characterized in that the composition for a water photovoltaic cable sheath satisfies all of the following Equations 10 to 12.

[Equation 10]

E ₁ ≥ 125 (Unit: %)

[Equation 11]

E ₂ ≥ 100 (unit: %)

[Equation 12]

X ≥ 30 (unit: %)

In Equation 10, E ₁ is the extruding and crosslinking process of a dumbbell specimen prepared according to IEC 60811-501 standards for a sheath separated from a water photovoltaic cable including a sheath layer prepared from the composition for a water photovoltaic cable sheath. After time, it means the elongation rate among the non-aging properties measured at a tensile rate of 250±50 mm/min using a tensile test facility, and in Equation 11, E ₂ is the sheath prepared from the composition for the water-borne solar cable sheath. Dumbbell specimens prepared according to the IEC 60811-511 standard of the sheath separated from the floating solar cable including the layer were placed in a base solution (N-Sodium hydroxide, 1N, 23±2℃) according to the IEC 60811-404 standard for 168 hours. It means the elongation rate in the base resistance measured at a tensile rate of 250±50 mm/min using a tensile test facility after putting it in for a while and then taking it out, and in Equation 12, X is the sheath prepared from the composition for the water photovoltaic cable sheath. Low-temperature elongation measured at a tensile rate of 25±5 mm/min using a tensile test facility installed inside a low-temperature chamber on a dumbbell specimen manufactured in accordance with IEC 60811-501 of a sheath separated from a floating solar cable including a layer means

In addition, the present invention provides a composition for a water photovoltaic cable sheath, characterized in that the composition for a water photovoltaic cable sheath satisfies all of the following Equations 13 to 15.

[Equation 13]

Z ≥ 0.816 (Unit: kgf/mm ² )

[Equation 14]

-30 ≤ △E ≤ +30 (Unit: %)

[Equation 15]

H ≤ 100 (unit: %)

In Equation 13, Z is a dumbbell specimen prepared according to the IEC 60811-501 standard for a sheath separated from a water-based solar cable including a sheath layer prepared from the composition for a water-based solar cable sheath Extrusion and cross-linking process 16 hours After that, it means the tensile strength among the non-aging properties measured at a tensile rate of 250±50 mm/min using a tensile test facility, and in Equation 14, ΔE is the sheath prepared from the composition for the water-borne solar cable sheath. Dumbbell specimens prepared according to the IEC 60811-511 standard of the sheath separated from the floating solar cable including the layer were placed in an acid solution (N-Oxalic Acid, 1N, 23±2℃) according to the IEC 60811-404 standard for 168 hours. It means the rate of change compared to the tensile strength in acid resistance measured at a tensile rate of 250±50 mm/min using a tensile test facility after putting it in for a while, and in Equation 15, H is from the composition for the water solar cable sheath. Dumbbell specimens manufactured according to the IEC 60811-501 standard for the sheath separated from the floating photovoltaic cable including the manufactured sheath layer were marked at intervals of 20 mm in the middle, and then placed on the specimen in a chamber at a temperature of 200±3℃. It refers to the rate of change (Hot) measured by hanging a load (weight) of 20.4N/cm ² (based on the cross-sectional area) and exposing it for 15 minutes, and then measuring the extended length (marked interval).

In addition, the present invention is a conductor; an insulating layer provided to surround the outer periphery of the conductor; And it provides a water-based solar cable comprising a sheath layer prepared from the above-described composition for a water-based solar cable sheath.

In addition, the present invention provides a water-based solar cable, characterized in that the water-based solar cable satisfies the following Equation 16.

[Equation 16]

50 ≤ L ≤ 540 (unit: mm)

In Equation 16, L is the digested length in the flame retardant test measured in accordance with the IEC 60332-1-2 standard for the cable specimen by making a specimen 16 hours or more after the crosslinking process is completed in the finished product of the water photovoltaic cable. means

The composition for a water photovoltaic cable sheath according to the present invention and a water photovoltaic cable comprising a cable sheath prepared therefrom can satisfy all the physical properties required in the international standard (IEC 62930) required for cable use, and additionally Various environmental resistance characteristics can be satisfied.

The accompanying drawings are intended to explain the contents of the present invention in more detail to those skilled in the art, but the technical spirit of the present invention is not limited thereto.
1 is a conceptual diagram for a floating solar power system related to the present invention.
Figure 2 is a cross-sectional view schematically showing a water-borne solar cable according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The description below is only for specifying the embodiments, and is not intended to limit or limit the scope of rights according to the present invention. What a person of ordinary skill in the art related to the present invention can easily infer from the detailed description and embodiments of the invention should be construed as belonging to the scope of the present invention.

Although the terms used in the present invention have been described as general terms widely used in the technical field related to the present invention, the meaning of the terms used in the present invention is the intention of a technician in the relevant field, the emergence of new technology, examination standards or precedents. It may vary depending on Some terms may be arbitrarily selected by the applicant, and in this case, the meaning of the arbitrarily selected terms will be described in detail. Terms used in the present invention should be interpreted as meanings reflecting the overall context of the specification, not just dictionary meanings.

Terms such as 'consisting of' or 'comprising' used in the present invention should not be construed as necessarily including all of the components or steps described in the specification, and if some components or steps are not included, And when additional components or steps are further included, it should also be construed as intended from the term.

Hereinafter, the present invention will be described in detail.

The present invention relates to a composition for a cable sheath.

More specifically, the present invention relates to a composition suitable for use in a water-based solar cable sheath among the compositions for a cable sheath (hereinafter referred to as “composition for water-based solar cable sheath” or “composition for cable sheath”).

In one example, the composition for a waterborne solar cable sheath may include a base resin.

The base resin is ethylene vinyl acetate (EVA) resin; and a polyolefin resin grafted with a polar moiety.

The ethylene vinyl acetate resin is not particularly limited, but for example, the content of units derived from vinyl acetate in the resin may be 15 wt% to 40 wt%.

As used herein, the term "derived unit" may refer to a structural unit in which a monomer is polymerized to form a polymer.

The polyolefin resin grafted with the polar moiety may have a melting temperature (T _m ) of 50°C to 90°C.

As used herein, the term “polar moiety” may refer to a polar group, and may refer to a side chain introduced into a main chain in a polymer.

In addition, as used herein, the term "grafted" may mean that a polyolefin resin is used as a main chain and a polar moiety is provided as a side chain.

In one example, the polar moiety may be anhydride, and more specifically maleic anhydride.

In an exemplary embodiment of the present invention, the polyolefin resin grafted with the polar moiety may be a polyolefin resin grafted with maleic anhydride.

In an exemplary embodiment of the present specification, the polyolefin resin grafted with the polar moiety is ethylene vinyl acetate grafted with maleic anhydride, high-density polyethylene grafted with maleic anhydride, polypropylene grafted with maleic anhydride, anhydrous It may be polyethylene acrylate grafted with maleic acid or polyethylene elastomer grafted with maleic anhydride, preferably ethylene vinyl acetate grafted with maleic anhydride.

When the melting temperature of the polyolefin resin grafted with the polar moiety is less than 50°C, a problem may occur in dispersing the additive due to low viscosity during compound manufacturing, and if it exceeds 90°C, scorch occurs during cable extrusion This can happen.

In one example, the composition for a water photovoltaic cable sheath may include a flame retardant to ensure flame retardancy and heat resistance.

The flame retardant may be included in an amount of 80 parts by weight to 153 parts by weight based on 100 parts by weight of the base resin.

The content of the flame retardant is preferably included in the above-described range, and when included in less than 80 parts by weight or in excess of 153 parts by weight based on 100 parts by weight of the base resin, when produced as a specimen of the composition for sheath to be described later, The low-temperature elongation test of the specimen, the rate of change compared to the tensile strength and the rate of change compared to the elongation during the damp heat test test do not meet the requirements related to the physical properties, and the cable prepared from the composition for the sheath is the physical property for use as a floating solar cable. There may be problems that do not meet the requirements of bending test, long-term DC insulation resistance test, flame retardancy test and smoke density test.

The type of the flame retardant is not particularly limited, but for example, it is preferable to include a mixture of an inorganic metal-based flame retardant and a phosphorus-based flame retardant.

The type of the inorganic metal-based flame retardant is not particularly limited, but, for example, aluminum hydroxide (Alumina Trihydrate, ATH) or magnesium hydroxide (Magnesium Hydroxide, MDH) may be used alone or in mixture of two or more, preferably may use magnesium hydroxide (MDH).

Since the phosphorus-based flame retardant can exhibit a flame retardant effect by reacting with oxygen element in the polymer resin included in the base resin to dehydrate and carbonize, it can effectively perform a flame retardant role in a polymer containing an oxygen element. As the type of the phosphorus-based flame retardant, phosphoric acid ester, halogen phosphoric acid ester, non-halogen condensed phosphorus-based flame retardant, polyphosphate-based and red-based flame retardant may be used alone or in combination of two or more, but is not particularly limited thereto, preferably A red flame retardant may be used.

In one example, the composition for the water photovoltaic cable sheath, based on 100 parts by weight of the base resin, 80 parts by weight to 150 parts by weight of an inorganic metal-based flame retardant; and 0.5 to 3 parts by weight of a phosphorus-based flame retardant.

The content of the inorganic metal-based flame retardant and the phosphorus-based flame retardant is preferably included in each of the above ranges, and if the content of the inorganic metal-based flame retardant is less than 80 parts by weight based on 100 parts by weight of the base resin, or exceeds 150 parts by weight When included as, or when the content of the phosphorus-based flame retardant is included in less than 0.5 parts by weight or more than 3 parts by weight based on 100 parts by weight of the base resin, when producing a specimen of the composition for sheath to be described later, the low temperature of the specimen During the elongation test, the damp heat test test, the rate of change compared to the tensile strength and the rate of change compared to the elongation rate do not meet the physical property-related requirements, and the cable prepared from the composition for the sheath is a low-temperature bending test, which is a physical property for use as a floating solar cable. There may be problems that do not meet the requirements of DC insulation resistance test, flame retardancy test and smoke density test.

In one example, the composition for a water-based solar cable sheath may satisfy the following Equations 1 to 3.

[Formula 1]

A ≤ 40 (unit: %)

[Formula 2]

-15 ≤ ㅿTS ≤ 15 (Unit: %)

[Equation 3]

-20 ≤ ㅿE ≤ 20 (Unit: %)

In Equation 1, A is a dumbbell specimen prepared according to the IEC 60811-511 standard for a sheath separated from a water photovoltaic cable including a sheath layer prepared from the composition for a water photovoltaic cable sheath under 50% RH humidity. It refers to the rate of change of the mass of the dumbbell specimen measured after storage and pretreatment for 7 days, and then taking out the dumbbell specimen after maintaining immersion in a water bath at 50° C. for 100 days compared to the mass of the measured dumbbell specimen, in Equation 2, ㅿTS is The sheath separated from the water photovoltaic cable including the sheath layer prepared from the composition for the water photovoltaic cable sheath was pretreated by storing the dumbbell specimen prepared according to the IEC 60811-511 standard for 7 days under 50% RH humidity, It means the rate of change of tensile strength (ㅿTS100 - ㅿTS28 / ㅿTS28) measured after maintaining the immersion of the dumbbell specimen in a water bath at 50 ° C for 28 days (ㅿTS28) and 100 days (ㅿTS100), respectively, and the above formula In 3, ㅿE is a dumbbell specimen prepared according to the IEC 60811-511 standard for a sheath separated from a water photovoltaic cable including a sheath layer prepared from the composition for a water photovoltaic cable sheath, under 50% RH humidity for 7 days. After storage and pretreatment, the rate of change in elongation measured after maintaining the immersion in the dumbbell specimen for 28 days (ㅿE28) and 100 days (ㅿE100) in a water bath at 50°C (ㅿE100 - ㅿE28 / ㅿE28) it means.

In addition to the base resin, the composition for a water photovoltaic cable sheath according to the present invention includes, as described above, with respect to 100 parts by weight of the base resin, 80 parts by weight to 150 parts by weight of an inorganic metal-based flame retardant; And 0.5 parts by weight to 3 parts by weight of a phosphorus-based flame retardant; By including, the cable including the sheath layer containing the composition for the cable sheath meets the criteria required in the above Equations 1 to 3, that is, the immersion evaluation test, It can be suitably applied to an optical cable.

In one example, the base resin, 70 parts by weight to 90 parts by weight of ethylene vinyl acetate (EVA) resin; and 10 parts by weight to 30 parts by weight of a polyolefin resin grafted with a polar moiety.

The composition for a cable sheath according to the present invention, based on 100 parts by weight of the total resin, 70 parts by weight to 90 parts by weight of ethylene vinyl acetate (EVA) resin; and 10 parts by weight to 30 parts by weight of a polyolefin resin grafted with a polar moiety; may include as a base resin,

The ethylene vinyl acetate (EVA) resin included in the base resin is preferably included in the above-mentioned content range, and the content of the ethylene vinyl acetate (EVA) is included in less than 70 parts by weight based on 100 parts by weight of the total resin, When included in more than 90 parts by weight as a specimen of the composition for a sheath to be described later, it does not meet the requirements in the low-temperature elongation test of the specimen, and the cable prepared from the composition for the sheath is used for the purpose of a water-borne solar cable. There may be problems that do not meet the requirements of low-temperature bending test and dynamic penetration test, which are physical properties.

In addition, even in the case of the polyolefin resin grafted with a polar moiety among the base resins included in the composition for cable sheath, it is preferably included in the above-described content range, and the content of the polyolefin resin grafted with the polar moiety is When included in less than 10 parts by weight based on 100 parts by weight of the total resin, or when included in more than 30 parts by weight as a specimen of the composition for sheath to be described later, it does not meet the requirements in the low-temperature elongation test of the specimen, and the composition for sheath There may be problems in that the cable manufactured by the company does not meet the requirements of low-temperature bending test and dynamic penetration test, which are physical properties for use in floating solar cables.

In one example, the composition for a water-borne solar cable sheath may satisfy Equation 4 below.

[Equation 4]

X ≥ 30 (unit: %)

In Equation 4, X is a dumbbell specimen prepared according to IEC 60811-501 standard for a sheath separated from a water photovoltaic cable including a sheath layer prepared from the composition for a water photovoltaic cable sheath, tension installed inside the low temperature chamber It means the low-temperature elongation measured at a tensile rate of 25±5 mm/min using a test facility.

The composition for a waterborne solar cable sheath according to the present invention is a base resin, and as described above, 70 parts by weight to 90 parts by weight of ethylene vinyl acetate (EVA) resin; And by including a polyolefin resin grafted with 10 to 30 parts by weight of a polar moiety, the above Equation 4, that is, by satisfying the standards required in the specification for elongation at low temperature, to be suitably applied to a sheath for a floating solar cable can

In one example, the composition for a waterborne solar cable sheath may include an antioxidant capable of improving thermal stability by preventing oxidation of the composition.

The type of the antioxidant is not particularly limited, but, for example, phenol-based, phosphorus-based, amine-based, zinc-based (eg, MBZ, ZnO) and triazole-based antioxidants may be used alone or in combination of two or more. , preferably a phenol-based antioxidant may be used.

In one example, the composition for a water-based solar cable sheath may include a UV stabilizer together to further improve the thermal stability of the composition in addition to the above-described antioxidant.

The UV stabilizer may be used alone or in combination of two or more selected from the group consisting of a metal deactivator, a heat stabilizer, an ultraviolet absorber, a quencher, a peroxide decomposer, a radical scavenger, and HALS, and carbon black is used. Preferably, it is not particularly limited thereto.

In one example, the composition for a waterborne solar cable sheath, with respect to 100 parts by weight of the base resin, 5 parts by weight to 20 parts by weight of an antioxidant; and 5 parts by weight to 10 parts by weight of a UV stabilizer or carbon black.

With respect to 100 parts by weight of the base resin, the antioxidant is preferably included in the above-described content range, and the content of the antioxidant is included in less than 5 parts by weight or more than 20 parts by weight based on 100 parts by weight of the base resin. When included, when producing a specimen of the composition for sheath to be described later, tensile strength, temperature index, residual tensile strength versus tensile strength in weather resistance / UV test, residual elongation versus elongation, and required values in low temperature elongation test among the non-aging properties of the specimen A problem may occur that does not meet the requirements of the ozone resistance test, which is a physical property for the cable manufactured from the composition for the sheath to be used for the purpose of a floating solar cable.

In addition, with respect to 100 parts by weight of the base resin, it is preferable that the UV stabilizer or carbon black is also included in the above-described content range, and the content of the UV stabilizer or carbon black is 5 parts by weight based on 100 parts by weight of the base resin. When included in less than or included in more than 10 parts by weight, when producing a specimen of the composition for sheath to be described later, tensile strength, Temperature Index, and tensile strength in weather resistance/UV test among non-aging physical properties of the specimen compared to tensile residual ratio/elongation ratio It does not meet the requirements in the elongation residual rate and low temperature elongation test, and the cable prepared from the composition for the sheath does not meet the requirements of the ozone resistance test, which is a physical property for use in the use of a floating solar cable.

In one example, the composition for a water-based solar cable sheath may satisfy all of the following Equations 5 to 7.

[Equation 5]

X ≥ 30 (unit: %)

[Equation 6]

Y ₁ ≥ 70 (unit: %)

[Equation 7]

Y ₂ ≥ 70 (unit: %)

In Equation 5, X is a dumbbell specimen prepared in accordance with IEC 60811-511 standards for a sheath separated from a water photovoltaic cable including a sheath layer prepared from the composition for a water photovoltaic cable sheath, tension installed inside a low temperature chamber It means a low-temperature elongation rate measured at a tensile rate of 25±5 mm/min using a test facility, and in Equation 6, Y ₁ is waterborne sunlight including a sheath layer prepared from the composition for the water-borne solar cable sheath. Dumbbell specimens prepared according to IEC 60811-501 standards of the sheath separated from the cables are put in a weathering test facility, exposed for 720 hours, and then taken out, and then the specimens are stored at 25±5℃, 50%RH for 18 hours, It means the residual tensile strength versus the tensile strength during the weather resistance/UV test measured at a tensile rate of 25±5 mm/min using a tensile test facility, and in Equation 7, Y ₂ is prepared from the composition for the water-borne solar cable sheath Dumbbell specimens prepared according to IEC 60811-501 standards of the sheath separated from the floating solar cable including the sheath layer were put in a weathering test facility, exposed for 720 hours, and then taken out, and the specimens were removed at 25±5℃, 50 It means the residual elongation compared to the elongation during the weather resistance/UV test measured at a tensile rate of 25±5 mm/min using a tensile test facility after storage at %RH for 18 hours.

In addition, in one example, the composition for a water photovoltaic cable sheath may satisfy both Equations 8 and 9 below.

[Equation 8]

Z ≥ 0.816 (Unit: kgf/mm ² )

[Equation 9]

T ≥ 120 (unit: ℃)

In Equation 8, Z is a dumbbell specimen prepared according to the IEC 60811-501 standard for a sheath separated from a water-based solar cable including a sheath layer prepared from the composition for a water-based solar cable sheath Extrusion and cross-linking process 16 hours Thereafter, it means the tensile strength among non-aging properties measured at a tensile rate of 250±50 mm/min using a tensile test facility, and in Equation 9, T is a sheath layer prepared from the composition for a water-based solar cable sheath. It means the Temperature Index calculated by selecting the end-point as 50% elongation based on IEC 60216-1 and IEC 62930 for a dumbbell specimen manufactured according to IEC 60811-511 standard of a sheath separated from a floating solar cable containing do.

The composition for a water-based solar cable sheath according to the present invention, with respect to 100 parts by weight of the base resin contained in the composition, 5 parts by weight to 20 parts by weight of an antioxidant; and 5 to 10 parts by weight of a UV stabilizer or carbon black; by including, among the above formulas 5 to 9, that is, elongation at low temperature, weather resistance / tensile strength vs. tensile strength / residual elongation vs. elongation, non-aging properties By satisfying the standards required by the standards related to tensile strength and temperature index properties, it can be suitably applied to the sheath for floating solar cables.

In one example, the composition for a waterborne solar cable sheath may include a crosslinking agent and a crosslinking aid in order to reinforce thermal, mechanical and chemical properties by crosslinking the molecules of the resin included in the composition.

The type of the crosslinking agent is not particularly limited, but, for example, dicumyl peroxide (DCP), perkadox or peroxan may be used alone or in combination of two or more. have.

In addition, the type of the crosslinking aid is not particularly limited, but for example, TAIC (Trially Isocyanurate), TAC (Trially Cyanurate), TMPTMA (Trimethylolpropane Trimethacrylate) or TMPTA (Trimethylolpropane Triacrylate), etc. alone or two or more It can be used by mixing.

In one example, the composition for a water photovoltaic cable sheath, with respect to 100 parts by weight of the base resin, 2 parts by weight to 10 parts by weight of a crosslinking agent; and 0.5 to 3 parts by weight of a crosslinking aid may be additionally included.

With respect to 100 parts by weight of the base resin, the crosslinking agent is preferably included in the above-described content range. When the content of the crosslinking agent is included in less than 2 parts by weight or more than 10 parts by weight based on 100 parts by weight of the base resin. When producing a specimen of the composition for sheath, which will be described later, tensile strength/elongation among the non-aging properties of the specimen, change rate of tensile strength compared to acid resistance, elongation rate among base resistance, increased length change rate (Hot) and low temperature elongation among hot/set items Problems may arise that do not meet the requirements of the test.

In addition, with respect to 100 parts by weight of the base resin, the crosslinking aid is preferably included in the above-mentioned content range, and the content of the crosslinking aid is included in less than 0.5 parts by weight based on 100 parts by weight of the base resin, or 3 When included in more than parts by weight, when producing a specimen of the composition for sheath to be described later, tensile strength/elongation among the non-aging properties of the specimen, change rate of tensile strength among acid resistance, elongation rate among base resistance, and length change rate among Hot/Set items (Hot) and low temperature elongation test may have a problem that does not meet the requirements.

In one example, the composition for the water-borne solar cable sheath may satisfy all of the following Equations 10 to 12.

[Equation 10]

E ₁ ≥ 125 (Unit: %)

[Equation 11]

E ₂ ≥ 100 (unit: %)

[Equation 12]

X ≥ 30 (unit: %)

In Equation 10, E ₁ is the extruding and crosslinking process of a dumbbell specimen prepared according to IEC 60811-501 standards for a sheath separated from a water photovoltaic cable including a sheath layer prepared from the composition for a water photovoltaic cable sheath. After time, it means the elongation rate among the non-aging properties measured at a tensile rate of 250±50 mm/min using a tensile test facility, and in Equation 11, E ₂ is the sheath prepared from the composition for the water-borne solar cable sheath. Dumbbell specimens prepared according to the IEC 60811-511 standard of the sheath separated from the floating solar cable including the layer were placed in a base solution (N-Sodium hydroxide, 1N, 23±2℃) according to the IEC 60811-404 standard for 168 hours. It means the elongation rate in the base resistance measured at a tensile rate of 250±50 mm/min using a tensile test facility after putting it in for a while and then taking it out, and in Equation 12, X is the sheath prepared from the composition for the water photovoltaic cable sheath. Low-temperature elongation measured at a tensile rate of 25±5 mm/min using a tensile test facility installed inside a low-temperature chamber on a dumbbell specimen manufactured in accordance with IEC 60811-501 of a sheath separated from a floating solar cable including a layer means

In addition, in one example, the composition for the water photovoltaic cable sheath may satisfy all of the following Equations 13 to 15.

[Equation 13]

Z ≥ 0.816 (Unit: kgf/mm ² )

[Equation 14]

-30 ≤ △E ≤ +30 (Unit: %)

[Equation 15]

H ≤ 100 (unit: %)

In Equation 13, Z is a dumbbell specimen prepared according to the IEC 60811-501 standard for a sheath separated from a water-based solar cable including a sheath layer prepared from the composition for a water-based solar cable sheath Extrusion and cross-linking process 16 hours After that, it means the tensile strength among the non-aging properties measured at a tensile rate of 250±50 mm/min using a tensile test facility, and in Equation 14, ΔE is the sheath prepared from the composition for the water-borne solar cable sheath. Dumbbell specimens prepared according to the IEC 60811-511 standard of the sheath separated from the floating solar cable including the layer were placed in an acid solution (N-Oxalic Acid, 1N, 23±2℃) according to the IEC 60811-404 standard for 168 hours. It means the rate of change compared to the tensile strength in acid resistance measured at a tensile rate of 250±50 mm/min using a tensile test facility after putting it in for a while, and in Equation 15, H is from the composition for the water solar cable sheath. Dumbbell specimens manufactured according to the IEC 60811-501 standard for the sheath separated from the floating photovoltaic cable including the manufactured sheath layer were marked at intervals of 20 mm in the middle, and then placed on the specimen in a chamber at a temperature of 200±3℃. It refers to the rate of change (Hot) measured by hanging a load (weight) of 20.4N/cm ² (based on the cross-sectional area) and exposing it for 15 minutes, and then measuring the extended length (marked interval).

The composition for a water photovoltaic cable sheath according to the present invention, with respect to 100 parts by weight of the base resin, 2 parts by weight to 10 parts by weight of a crosslinking agent; And 0.5 parts by weight to 3 parts by weight of a crosslinking aid by additionally including, Equations 9 to 14, that is, tensile strength/elongation among non-aging properties, elongation in base resistance, elongation at low temperature, tensile strength in acid resistance, and Hot/Set By satisfying the criteria required in the standard for the increased length ratio in the test (Hot), it can be appropriately applied to the sheath for the floating solar cable.

In addition to the above-described configuration, the composition for a water-based solar cable sheath according to the present invention is not particularly limited, but, for example, in order to supplement the required physical properties, various additives, that is, nanoclay, high molecular weight wax, low molecular weight wax, polyolefin One selected from the group consisting of lubricants such as wax, paraffin wax, paraffin oil, stearic acid, metal soap, organic silicone, fatty acid ester, fatty acid amide, fatty alcohol, fatty acid, reinforcing agent, release agent, stabilizer, pigment, dye and colorant Or two or more may be additionally included.

The present invention also relates to a floating solar cable.

More specifically, the present invention relates to a waterborne solar cable comprising a sheath layer prepared from the above-described composition for a waterborne solar cable sheath.

Figure 2 is a cross-sectional view schematically showing a water-borne solar cable according to an embodiment of the present invention.

Referring to Figure 2, the solar water cable 300 according to the present invention, the conductor 20; an insulating layer 21 provided to surround the outer periphery of the conductor; And it may include a sheath layer 200 prepared from the above-mentioned composition for a water-based solar cable sheath.

The sheath layer 200 is manufactured from the above-described composition for a water-based photovoltaic cable sheath, and the contents overlapping with the above-described contents will be omitted below.

The conductor 20 may have a composite stranded wire structure made by twisting a plurality of metal wires at a constant pitch, and the metal wire may be made of a single metal or at least two or more metal alloys. That is, the metal wire may be made of a metal selected from copper, aluminum, iron, and nickel or an alloy of these metals, but is not particularly limited thereto.

The insulating layer 21 may be formed using an insulating composition as a polymer resin layer surrounding the conductor by extrusion molding on the outside.

Although not particularly limited, the insulating layer may include polyolefin elastomer (POE); ethylene propylene rubber (EPDM); and polyethylene (PE) as a base resin.

In addition, if necessary, various additional components may be included in the insulating layer composition, for example, antioxidants, UV stabilizers, crosslinking agents, and crosslinking aids may be applied in the same manner as in the examples in the above-described composition for cable sheath.

In one embodiment of the present invention, the photovoltaic cable may be manufactured according to a general method of manufacturing a cable, except that the sheath is formed using the sheath composition.

Specifically, in one embodiment, the photovoltaic cable comprises the steps of preparing a conductor; forming an insulating layer on the conductor using an insulating composition; and forming a sheath layer on the insulating layer using a sheath composition.

In the present invention, in the step of forming the insulating layer and the step of forming the sheath layer, each layer may be separately extruded sequentially or sequentially, or may be extruded simultaneously.

In addition, in the present invention, in the step of forming the insulating layer and the step of forming the sheath, it is crosslinked through CCV (Catenary Continuous Vulcanizing: Suspended continuous extrusion system) equipment, crosslinked using water crosslinking, or irradiation crosslinking can be cross-linked using

In one example, the water photovoltaic cable may satisfy Equation 16 below.

[Equation 16]

50 ≤ L ≤ 540 (unit: mm)

In Equation 16, L is the digested length in the flame retardant test measured in accordance with the IEC 60332-1-2 standard for the cable specimen by making a specimen 16 hours or more after the crosslinking process is completed in the finished product of the water photovoltaic cable. means

The waterborne solar cable according to the present invention, by including the sheath layer prepared from the above-described composition for the waterborne solar cable sheath, the above Equation 16, that is, it can satisfy the requirements of the flame retardant test items required as a waterborne solar cable.

Hereinafter, examples will be given to describe the present invention in detail. However, the embodiments according to the present invention may be modified in various other forms, and the scope of the present invention is not to be construed as being limited to the embodiments described below. The embodiments of the present specification are provided to more completely explain the present invention to those of ordinary skill in the art.

[Experimental design and related standards]

For the sheath among the underwater solar cables used in the floating solar power system, the experimental method and evaluation criteria were designed based on the criteria shown in Table 1 below. Each evaluation was measured according to IEC.

division Test Items unit demand One Non-aging properties (IEC 60811-501) ^b Exam conditions - - Temperature ℃ 23±5 Metrics - - Tensile strength (250±50mm/min, average, min.) kg _f /mm ² 0.816 or higher Elongation (250±50 mm/min, average, min.) % over 125 2 Temperature Index (IEC 60216-1 and IEC 60216-2) ^b Exam conditions - - Failure criteria: elongation rate % 50 Metrics - - Ti(Temperature index at 20,000h) ℃ over 120 3 N-Oxalic Acid Resistance ^c (IEC 60811-404) Exam conditions - - - exposure temperature ℃ 23±2 - exposure time h 168 Metrics - - Rate of change compared to tensile strength (max.) % ±30 Elongation (min.) % over 100 4 Base resistance (N-Sodium hydroixde) ^c (IEC 60811-404) Exam conditions - - - exposure temperature ℃ 23±2 - exposure time h 168 Metrics - - Rate of change compared to tensile strength (max.) % ±30 Elongation (min.) % over 100 5 Weathering/UV test (IEC 62930 Annex E) Exam conditions - - - exposure time h 720 - xenon arc lamp W/m ² 60 ± 15% (300nm ~ 400nm) - conductivity of deionized water μS/cm < 5 - Cycle cycle 360 dry radiation exposure - 102min (60±3℃, RH 50±10%) rain exposure - 18 min(50±3℃, No radiation & RH control) Metrics - - - Tensile residual ratio to tensile strength (min.) % over 70 - Residual kidney ratio compared to elongation rate (min.) % over 70 6 Hot/set (IEC 60811-507) ^b Exam conditions - - - exposure temperature ℃ 200±3 - exposure time min 15 - weight N/cm ² 20.4 Metrics - - Hot (percentage of length change under test conditions, max.) % less than 100 Set(Ratio of change in length after taking out of the oven and shrinking, max.) % less than 25 7 Low temperature elongation test (IEC 60811-505) ^b Exam conditions - - - exposure temperature ℃ -40±2 - exposure time h 4 Metrics - - Elongation (25mm/min, min.) % 30 or more 8 Damp heat test (IEC 60068-2-78) Exam conditions - - - exposure temperature ℃ 90±2 - exposure time h 1000 - Exposure Relative Humidity (Min.) % 85 - reconditioning period
(stabilization time after test) h 16 to 24 Metrics - - - Rate of change compared to tensile strength (max.) % over -30 ^a - Rate of change compared to elongation (max.) % over -30 ^a a. Only negative values are accepted
b. The test is carried out by taking sheath samples from the finished cable.
c. N is 1 Normal Concentration

The specific method of each test was carried out as follows by applying the test conditions according to Table 1, etc.

[Specific test method]

1. Non-aging property test

1) Specimen production

When the total diameter is 12.5 mm or more or the main axis of the flat cable is 12.5 mm or more, specimens were prepared from the cable. In this case, when it was smaller than the diameter or the main axis, the specimen was prepared by press-crosslinking the raw material. The thickness of the specimen was manufactured to be at least 0.8 mm or more and 2 mm or less. All samples were stored at room temperature for at least 3 hours, and after that, specimens were prepared according to Figure 1 of IEC 60811-501, and the specimens were collected in the longitudinal direction.

2) Test method

After 16 hours of extrusion and crosslinking of the prepared specimen, the tensile speed was set to 250±50 mm/min, and tensile strength and elongation were measured, respectively.

2. Temperature Index test

1) Specimen production

When the total diameter is 12.5 mm or more or the main axis of the flat cable is 12.5 mm or more, specimens were prepared from the cable. In this case, when it was smaller than the diameter or the main axis, the specimen was prepared by press-crosslinking the raw material. The thickness of the specimen was manufactured to be at least 0.8 mm or more and 2 mm or less. All samples were stored at room temperature for at least 3 hours, and after that, specimens were prepared according to Figure 1 of IEC 60811-501, and the specimens were collected in the longitudinal direction.

2) Test method

The Temperature Index (Ti) test is a test that calculates the lifespan of a material, and it is to obtain a temperature having a lifespan of 20,000 hours. The Ti value was calculated by selecting the end-point as 50% elongation according to the term.

3. Acid resistance test

1) Specimen production

When the total diameter is 12.5 mm or more or the main axis of the flat cable is 12.5 mm or more, specimens were prepared from the cable. In this case, when it was smaller than the diameter or the main axis, the specimen was prepared by press-crosslinking the raw material. The thickness of the specimen was manufactured to be at least 0.8 mm or more and 2 mm or less. All samples were stored at room temperature for at least 3 hours, and after that, specimens were prepared according to Figure 1 of IEC 60811-501, and the specimens were collected in the longitudinal direction.

2) Refer to the test method IEC 60811-404

The prepared specimen was placed in an acid solution (N-Oxalic Acid, 1N, 23±2° C.) for 168 hours according to IEC 60811-404 standard, and then taken out, and the elongation rate was measured at a tensile speed of 250±50 mm/min.

4. Base resistance test

1) Specimen production

When the total diameter is 12.5 mm or more or the main axis of the flat cable is 12.5 mm or more, specimens were prepared from the cable. In this case, when it was smaller than the diameter or the main axis, the specimen was prepared by press-crosslinking the raw material. The thickness of the specimen was manufactured to be at least 0.8 mm or more and 2 mm or less. All samples were stored at room temperature for at least 3 hours, and after that, specimens were prepared according to Figure 1 of IEC 60811-501, and the specimens were collected in the longitudinal direction.

2) Refer to the test method IEC 60811-404

The prepared specimen was put in a base solution (N-Sodium hydroxide, 1N, 23±2℃) for 168 hours according to IEC 60811-404 standard, and then taken out, and the elongation rate was measured at a tensile speed of 250±50 mm/min.

5. Weather resistance/UV test

1) Specimen production

When the total diameter is 12.5 mm or more or the main axis of the flat cable is 12.5 mm or more, specimens were prepared from the cable. In this case, when it was smaller than the diameter or the main axis, the specimen was prepared by press-crosslinking the raw material. The thickness of the specimen was manufactured to be at least 0.8 mm or more and 2 mm or less. All samples were stored at room temperature for at least 3 hours, and after that, specimens were prepared according to Figure 1 of IEC 60811-501, and the specimens were collected in the longitudinal direction.

2) Test method

The prepared specimen was placed in a weathering test facility, exposed for 720 hours, and then the specimen was taken out. After the specimen was stored at 25±5° C. and 50% RH for 18 hours, a tensile test was performed to measure the tensile residual ratio and the elongation residual ratio compared to the unaged sample.

The specific environmental conditions of the weathering test facility refer to ISO 4892 as follows.

- Lamp : xenon Arc Lamp 60W/m ² ± 15% (300nm ~ 400nm)

- Conductivity of distilled water: < 5 μS/cm

- Cycle composition: total 360 cycles

- Dry radiation exposure: 102min (60±3℃, 50±10%RH)

- Rain exposure: 18min (60±3℃, no radiation & RH control)

Additionally, in order to create a weatherproof environment, the test was conducted by creating one cycle of UV exposure conditions for 102 minutes and rain conditions for 18 minutes.

6. Hot/Set test

1) Specimen production

When the total diameter is 12.5 mm or more or the main axis of the flat cable is 12.5 mm or more, specimens were prepared from the cable. In this case, when it was smaller than the diameter or the main axis, the specimen was prepared by press-crosslinking the raw material. The thickness of the specimen was manufactured to be at least 0.8 mm to 2 mm or less. All samples were stored at room temperature for at least 3 hours, and after that, specimens were prepared according to Figure 1 of IEC 60811-501, and the specimens were collected in the longitudinal direction.

2) Test method

^{After marking the manufactured dumbbell specimens at intervals of 20 mm in the middle, a load (weight) of 20.4 N/cm 2} (based on the cross-sectional area) was hung on the specimen in a chamber at a temperature of 200±3° C. and exposed for 15 minutes. , the length (marked interval) was measured to calculate the rate of change (Hot). In addition, after the specimen was further exposed to the chamber for 5 minutes after removal, the specimen was taken out and the length was measured when the specimen was sufficiently reduced to calculate the rate of change (Set).

7. Low temperature elongation test

1) Specimen production

When the total diameter is 12.5 mm or more or the main axis of the flat cable is 12.5 mm or more, specimens were prepared from the cable. In this case, when it was smaller than the diameter or the main axis, the specimen was prepared by press-crosslinking the raw material. The thickness of the specimen was manufactured to be at least 0.8 mm or more and 2 mm or less. All samples were stored at room temperature for at least 3 hours, and after that, specimens were prepared according to Figure 1 of IEC 60811-501, and the specimens were collected in the longitudinal direction.

2) Test method

After 16 hours of extrusion and crosslinking of the prepared specimen, the tensile rate was 25±5 mm/min, and the elongation rate was measured. Here, the tensile test equipment installed inside the low-temperature chamber was used for the elongation rate, and when using a liquid as a coolant, it was maintained at the temperature for at least 10 minutes or more. After maintaining in the elongation was measured.

8. Damp heat test

1) Specimen production

When the total diameter is 12.5 mm or more or the main axis of the flat cable is 12.5 mm or more, specimens were prepared from the cable. In this case, when it was smaller than the diameter or the main axis, the specimen was prepared by press-crosslinking the raw material. The thickness of the specimen was manufactured to be at least 0.8 mm to 2 mm or less. All samples were stored at room temperature for at least 3 hours, and after that, specimens were prepared according to Figure 1 of IEC 60811-501, and the specimens were taken in the longitudinal direction, but the sheath was removed from the finished product to prepare the specimen.

2) Test method

The prepared specimen is placed in a constant temperature / constant humidity tester at a temperature of 90 ± 2 ° C and a humidity of 85% RH, exposed for 1,000 hours and then taken out, and then the specimen is again stabilized at room temperature for 16 to 24 hours, the tensile rate is Tensile strength and elongation were measured at 250±50 mm/min, respectively.

In addition, the rate of change of the measured tensile strength and elongation with respect to the above-described non-aging test results with respect to tensile strength and elongation was calculated, respectively.

In addition, for the underwater photovoltaic cable used in the floating photovoltaic system, the experimental method and evaluation criteria were designed based on the criteria shown in Table 2 below. Each evaluation was measured according to IEC.

No. Test Items unit demand 9 Ozone resistance test (IEC 60811-403) Exam conditions - Measure as finished product - Temperature ℃ 25±2 - test time h 24 - Ozone concentration (vol%) % 250 to 300 x 10 ^-4 Metrics - - - Check the cable sheath appearance - no crack 10 Low temperature impact test (IEC 60811-506) Exam conditions - Measure as finished product - Temperature ℃ -40 - hour h 16 - Impact test conditions for each sample - - cable diameter, D weight
weight jig weight weight
fall height - - mm g g mm - - D ≤ 15 1,000 200 100 - - 15 < D ≤ 25 1,500 200 150 - - D > 25 2,000 200 200 - - Metrics - - - Cable exterior and internal components
Check for cracks - no crack 11 Low temperature bending test (IEC 60811-504) Exam conditions - - - Temperature ℃ -40±2 - test time h 4 - bend diameter (mendrel diameter) - 4 times the outer diameter - rotation speed times/sec 0.2 - number of turns according to diameter - - Sample diameter (mm) number of turns - - d < 2.5 10 - - 2.5 < d ≤ 4.5 6 - - 4.5 < d ≤ 6.5 4 - - 6.5 < d ≤ 8.5 3 - - 8.5 < d 2 - - Metrics - - - Cable exterior and internal components
Check for cracks - No Crack 12 Long-term DC insulation resistance (IEC 62821-2) Exam conditions - - - sample length (min.) m 5 - Immersion time (min.) h 240 - water temperature ℃ 85±5 - NaCl aqueous solution content g/L 10 - applied voltage kVdc 1.8 Metrics - - - Withstand voltage test - No break down 13 Dynamic Penetration (based on 150SQ) Exam conditions - - - number of tests episode 4 - Temperature ℃ RT - speed of pressure application N/s One - needle diameter mm 0.5±0.01 Metrics - - - Insulation breaking strength (average of 4 times) N 587 or higher 14 Flame retardant test (60332-1-2) Exam conditions - - - Propane gas purity (min.) % 98 - gas supply flow ml/min 650±30 - Oxygen supply flow ml/min 10±0.5 - inner blue flame length mm 50 - 60 - outer flame length mm 170 - 190 - Flame application time - - outer diameter of the sample flame application time - - mm sec - - D ≤ 25 60±2 - - 25 ≤ D ≤ 50 120±2 - - 50 ≤ D ≤ 75 240±2 - - D > 75 480±2 - - Metrics - - - the distance between the upper fixture and the highest point of combustion (min.) mm 50 - the distance between the upper fixture and the lowest point of combustion (max.) mm 540 15 Smoke density (IEC 61034) Exam conditions - - - test time min 40 Metrics - Test as finished product
(Several 100mm) - Light transmittance (min.) % over 60

The specific method of each test was carried out as follows by applying the test conditions according to Table 2 above.

[Specific test method]

9. Ozone resistance test

1) Specimen production

When the total diameter is 12.5 mm or more or the main axis of the flat cable is 12.5 mm or more, specimens were prepared from the cable. In this case, when it was smaller than the diameter or the main axis, the specimen was prepared by press-crosslinking the raw material. The thickness of the specimen was manufactured to be at least 0.8 mm to 2 mm or less. All samples were stored at room temperature for at least 3 hours. After that, specimens were prepared according to Figure 1 of IEC 60811-501, and the specimens were taken in the longitudinal direction, but two dumbbell specimens with a thickness of 0.6 mm or more were prepared from the finished product. did.

2) Test method

According to the IEC 60811-403 standard, the ozone concentration in the chamber is 250 ~ 300 × 10 ^-4 vol%, the temperature is 25±2℃, hold the both ends of the prepared specimen with clamps, and after increasing by 33±2% , and then exposed for 24 h in the chamber. Thereafter, it was checked whether cracks occurred in the exterior of the exposed specimen.

10. Low temperature impact test

1) Specimen production

Specimens that have passed 16 hours or more after the crosslinking process of the finished cable is completed were used.

2) Test method

According to the IEC 60811-506 standard, after exposing the prepared specimen in a chamber at -40°C for 16 hours, an impact test (Table.2, Paragraph 10) was performed by varying the weight and drop height for each specimen. Thereafter, it was checked whether cracks occurred in the exterior and internal structures of each specimen.

11. Low temperature bending test

1) Specimen production

Specimens that have passed 16 hours or more after the crosslinking process of the finished cable is completed were used.

2) Test method

According to IEC 60811-504 standard, after exposing the prepared specimen in a chamber at -40°C for 16 hours, the number of revolutions (Table. ) was tightly wound on the After fixing each of the specimens wound on the mandrel, they were stored as they were until returned to room temperature. Thereafter, it was checked whether cracks occurred in the exterior and internal structures of the specimen.

12. Long-term DC insulation resistance test

1) Specimen production

Specimens that have passed 16 hours or more after the crosslinking process of the finished cable is completed were used. In the finished product, all other components (tape, sheath, etc.) existing on the insulation should be removed and the test should be conducted in the insulating state.

2) Test method

According to the IEC 62821-2 standard, the prepared specimen was immersed in an aqueous NaCl solution of -10 g/L concentration, 250 mm of both ends of each specimen were not immersed in the aqueous solution, and then the negative electrode (-) was connected to the conductor and the positive electrode ( After +) was connected to the aqueous solution, 1.8 kVdc was applied by immersion in an aqueous solution at 85±5° C. for 240 hours. In this case, it was checked whether break-down occurred for 240 hours.

13. Dynamic Penetration Test

1) Specimen production

Specimens that have passed 16 hours or more after the crosslinking process of the finished cable is completed were used.

2) Test method

According to IEC 62930 Annex D standard, press the specimen with a needle of 0.5±0.01 mm in diameter at room temperature, and conduct the test after making the axis of the needle and the cable specimen perpendicular. , the pressure on the cable specimen was increased at a rate of 1 N/s. Insulation and sheath included in the cable specimen were broken, and the pressure at the moment when the needle and the conductor came into contact was measured, and this test was repeated 4 times to calculate the average value.

In this case, the required pressure (F, newton) was calculated according to the following formula according to the diameter (d) of the cable specimen.

[Calculation formula]

≥ F = 150

14. Flame Retardant Test

1) Specimen production

Specimens that have passed 16 hours or more after the crosslinking process of the finished cable is completed were used.

2) Test method

In accordance with the IEC 60332-1-2 standard, a flame retardant test was performed.

15. Smoke Density Test

1) Specimen production

Specimens that have passed 16 hours or more after the crosslinking process of the finished cable is completed were used.

2) Test method

According to IEC 61034 standard, smoke density test was performed.

In addition, since the floating photovoltaic power generation cable according to the present invention must be an underwater cable to be installed in reservoirs and freshwater lakes, it must be certified for hygiene and safety standards in accordance with Article 14 of the Waterworks Act, and the sanitary and safety standards are based on a total of 44 types of hazardous substances. Since the permissible value for dissolution is limited, the actual test was conducted with the following examples and comparative examples in consideration of the relevant certifications and standards.

[Examples and Comparative Examples] Preparation of the sheath composition

Compounding was carried out while raising the temperature to about 110 °C using a kneader. In order to prevent scorching of the compound, a crosslinking agent was added at the last stage of compounding and kneading was performed for a short time.

The cis compounding composition is shown in Tables 3 to 5 below.

division Example comparative example 1.1 1.2 1.3 1.1 1.2 1.3 1.4 resin a 70 80 90 65 70 90 95 resin b 30 20 10 35 30 10 5 antioxidant 17 17 17 17 17 17 17 UV Stabilizer 8 8 8 8 8 8 8 Inorganic metal-based flame retardant 130 130 130 130 130 130 130 Phosphorus flame retardant 2 2 2 2 2 2 2 crosslinking aid 0.5 3 3 3 0.2 3.5 3 crosslinking agent 2 10 10 10 1.5 10.5 10

division Example comparative example 2.1 2.2 2.3 2.4 2.5 2.6 2.1 2.2 2.3 2.4 resin a 70 70 80 80 90 90 70 70 90 90 resin b 30 30 20 20 10 10 30 30 10 10 antioxidant 5 20 5 20 5 20 3 25 3 25 UV Stabilizer 5 10 5 10 5 10 3 15 3 15 Inorganic metal-based flame retardant 130 130 130 130 130 130 130 130 130 130 Phosphorus flame retardant 2 2 2 2 2 2 2 2 2 2 crosslinking aid 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 crosslinking agent 5 5 5 5 5 5 5 5 5 5

division Example comparative example 3.1 3.2 3.3 3.4 3.5 3.6 3.1 3.2 3.3 3.4 resin a 70 70 80 80 90 90 70 70 90 90 resin b 30 30 20 20 10 10 30 30 10 10 antioxidant 17 17 17 17 17 17 17 17 17 17 UV Stabilizer 8 8 8 8 8 8 8 8 8 8 Inorganic metal-based flame retardant 80 150 80 150 80 150 60 170 60 170 Phosphorus flame retardant 0.5 3 0.5 3 0.5 3 0.2 4 0.2 4 crosslinking aid 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 crosslinking agent 5 5 5 5 5 5 5 5 5 5

Components in Tables 3 to 5 are as follows, and the unit is each part by weight based on 100 parts by weight of the total resin.

Resin a: Ethylene vinyl acetate (EVA) resin (VA content: 32wt.%, Lotte Chemical)

Resin b: ethylene vinyl acetate resin grafted with maleic anhydride (melting temperature (T _m ): 71° C.)

Antioxidant: Phenolic antioxidant (Songwon Industrial Co., Ltd.)

UV Stabilizer: carbon black

Inorganic metal-based flame retardant: MDH

Phosphorus Flame Retardant: Enemy

The evaluation results are shown in Tables 6 to 8 below by applying the experimental methods and evaluation criteria to the criteria as in Table 1 of the sheath compositions prepared in Tables 3 to 5, and in this case, each evaluation was performed according to IEC. .

division unit baseline Example comparative example 1.1 1.2 1.3 1.1 1.2 1.3 1.4 Non-aging property test tensile strength kgf/mm ² 0.816
more 1.167 1.535 1.513 1.468 0.667 1.556 1.426 elongation % 125
more 276.45 130.55 135.09 142.50 345.50 119.50 144.68 Temperature Index
exam Ti ℃ 120
more 131.42 139.5 140.2 135.7 - 135.8 138.1 Mountain
resistance test Tensile strength vs.
rate of change % within ±30 -20.47 -8.58 -4.25 -11.43 -33.52 -1.25 -3.58 elongation % 100
more 186.76 122.99 126.75 132.78 135.40 105.91 135.85 base
resistance test Tensile strength vs.
rate of change % within ±30 -4.16 -6.07 +0.20 +4.19 +2.02 -4.85 +1.22 elongation % 100
more 160.40 172.75 202.42 246.27 99.94 223.15 186.42 Weather resistance/
UV test Tensile Residual Ratio to Tensile Strength % 70
more 102.75 103.11 103.85 100.52 101.52 98.52 102.44 elongation
prepare
Kidney Residual Rate % 70
more 91.52 85.75 89.75 91.19 88.25 94.85 96.75 Hot/
Set
exam Hot % 100
below 70 5 5 10 110 5 5 Set % 25
below 10 0 0 5 20 0 0 low temperature
elongation
exam elongation % 30
more 35 40 34 25 25 35 27 Damp heat
exam tensile strength
prepare
rate of change % -30
Excess -2.75 +2.00 +3.52 +5.76 -4.34 +5.74 +1.52 elongation
prepare
rate of change % -30
Excess -14.67 -12.69 -10.76 -11.89 -18.27 -8.48 -11.36

division unit baseline Example comparative example 2.1 2.2 2.3 2.4 2.5 2.6 2.1 2.2 2.3 non-aging
Properties
exam Seal
burglar kgf/mm ² 0.816
more 1.351 0.876 1.315 0.815 1.251 0.746 1.386 0.646 1.402 elongation % 125
more 215.13 315.67 254.76 316.80 264.00 338.40 200.53 351.70 210.60 Temperature Index
exam Ti ℃ 120
more 124 141 127 140 128 142 113 145 116 Mountain
resistance test Seal
rate of change versus intensity % within ±30 -5.88 -10.44 -5.66 -15.33 -2.67 -9.85 -4.19 -13.52 -1.87 elongation % 100
more 189.66 265.12 239.75 265.49 244.64 287.76 188.64 299.46 195.10 base
resistance test Seal
rate of change versus intensity % within ±30 -2.99 -4.14 -0.90 -3.83 -4.41 -4.34 -13.40 -8.10 -3.00 elongation % over 100 179.15 184.80 229.10 245.87 257.70 243.52 209.70 225.00 258.40 Weathering/UV test Seal
Tensile versus strength
balance % 70
more 75.66 97.68 73.56 103.41 76.85 97.34 69.02 98.11 68.51 elongation
prepare
kidney
balance % 70
more 74.99 92.45 78.84 98.81 81.25 95.14 68.95 91.64 66.15 Hot/
Set
exam Hot % 100
below 10 30 10 30 10 30 10 40 10 Set % 25
below 0 10 0 10 0 10 0 15 0 low temperature
elongation
exam elongation % 30
more 38 32 40 34 38 32 36 28 40 Damp heat
exam Seal
burglar
prepare
rate of change % -30
Excess +0.20 -4.88 +3.52 -0.48 +6.85 -1.48 +1.95 -5.65 +5.65 elongation
prepare
rate of change % -30
Excess -11.01 -15.84 -7.52 -15.03 -9.48 -11.88 -11.39 -13.48 -8.35

division unit baseline Example comparative example 3.1 3.2 3.3 3.4 3.5 3.6 3.1 3.2 3.3 Non-aging properties
exam Seal
burglar kgf/mm ² 0.816
more 1.452 1.512 1.385 1.368 1.352 1.367 1.425 1.515 1.402 elongation % 125
more 282.53 254.50 295.55 265.52 284.59 254.52 285.50 246.10 298.74 Temperature Index
exam Ti ℃ 120
more 140 138 139 137 139 138 141 135 139 Mountain
resistance test Seal
rate of change versus intensity % within ±30 -6.51 -5.72 -4.81 -8.48 -5.27 -7.48 -6.34 -8.66 -3.02 elongation % 100
more 257.56 233.45 266.85 242.52 240.52 239.51 257.91 215.65 287.00 base
resistance test Seal
rate of change versus intensity % within ±30 -18.50 -16.60 -8.40 -8.10 -3.00 -7.53 -4.58 -8.46 -6.58 elongation % over 100 271.70 264.40 293.20 225.00 258.40 211.90 189.95 175.95 195.35 Weathering/UV test Seal
Tensile versus strength
balance % 70
more 94.16 95.52 98.52 95.52 102.66 103.52 98.52 97.18 101.52 elongation
prepare
kidney
balance % 70
more 98.19 96.52 94.15 89.52 92.52 94.52 94.98 92.46 88.97 Hot/Set
exam Hot % 100
below 10 20 10 15 15 20 15 20 10 Set % 25
below 0 0 0 5 0 5 0 5 0 low temperature
elongation
hum elongation % 30
more 44 33 43 32 42 32 46 28 45 Damp heat
exam Seal
burglar
prepare
rate of change % -30
Excess +3.52 -23.48 +1.52 -25.48 +2.52 -24.35 +2.45 -30.39 +6.52 elongation
prepare
rate of change % -30
Excess -10.15 -21.48 -8.36 -23.75 -3.58 -22.48 -5.37 -31.35 -7.02

From the results of Tables 6 to 8, it can be confirmed that the sheath composition according to an exemplary embodiment of the present invention can satisfy all of the physical properties required as a sheath included in an underwater solar cable used in a floating solar power system. have.

Specifically, referring to Table 6, in the case of Comparative Examples 1.1 and 1.4, in which the content of the polyolefin resin grafted with the ethylene vinyl acetate resin and the polar moiety is not suitable, the low temperature elongation drops to less than 30%, and the ethylene vinyl In Comparative Examples 1.2 and 1.3, where the content of other sheath composition components (crosslinking aid and crosslinking agent) other than the content of the polyolefin resin grafted with the acetate resin and the polar moiety was not suitable, tensile strength among non-aging properties and acid resistance It was confirmed that the physical properties of contrast change rate, elongation rate during base resistance, hot item during hot/set test, and low temperature elongation did not satisfy the standard values.

In addition, referring to Table 7, in Comparative Examples 2.1 to 2.4, in which the content of the other sheath composition components (antioxidant and UV stabilizer) other than the content of the polyolefin resin grafted with the ethylene vinyl acetate resin and the polar moiety is not suitable, Among non-aging properties, it was confirmed that the physical properties of tensile strength, Temperature Index (Ti), weather resistance/UV test, tensile strength vs. tensile strength/residual elongation vs. elongation ratio, and low temperature elongation did not satisfy the standard values.

In addition, referring to Table 8, in Comparative Examples 3.1 to 3.4, the content of other sheath composition components (inorganic metal-based flame retardant and phosphorus-based flame retardant) other than the content of the polyolefin resin grafted with the ethylene vinyl acetate resin and the polar moiety is not suitable. , it was confirmed that the physical properties of the rate of change compared to tensile strength/rate of change compared to elongation during the low temperature elongation and damp heat tests did not satisfy the standard values.

[Examples and Comparative Examples] Manufacture of a floating solar cable

Cables were produced by extruding each of the sheath compositions of Examples and Comparative Examples prepared with the sheath compound components and content ratios of Tables 3 to 5 on the outer shell of the insulating layer surrounding the conductor. At this time, the extrusion temperature of the sheath composition was set to 90 °C to 110 °C. After extrusion, the sheath was cross-linked in a CV (Continuous Vulcanization) tube at 160°C to 200°C. For the conductor included in the cable for this evaluation, 150SQ conductor was used.

For each of the manufactured Example and Comparative Example cables, the test methods and evaluation criteria were evaluated based on the same standards as Table 2, which is the standard for underwater solar cables used in floating photovoltaic systems, and the evaluation results are shown in the following table 9 to Table 11. In this case, each evaluation was performed according to IEC.

division unit baseline Example comparative example 1.1 1.2 1.3 1.1 1.2 1.3 1.4 ozone resistance
exam Check the cable sheath appearance - No
crack Pass Pass Pass Pass Pass Pass Pass low temperature
Shock
exam Check cable appearance and internal components for cracks - No
crack Pass Pass Pass Pass Fail Pass Pass low temperature
bend
exam Check cable appearance and internal components for cracks - No
crack Pass Pass Pass Fail Fail Pass Pass long-term DC
Insulation Resistance
exam withstand voltage test - No
break down Pass Pass Pass Pass Pass Pass Pass Dynamic
Penetration
exam Insulation breaking strength
(Based on 150SQ) N 587
more 768 735 634 835 788 605 571 Flame Retardant
exam shot length mm 50 to 540 Pass Pass Pass Pass Pass Pass Pass smoke density
exam light transmittance % over 60 89 88 96 94 92 94 95

division unit baseline Example comparative example 2.1 2.2 2.3 2.4 2.5 2.6 2.1 2.2 2.3 Ozone resistance test Check the cable sheath appearance - No
crack Pass Pass Pass Pass Pass Pass Fail Pass Fail low temperature
Shock
exam Check cable appearance and internal components for cracks - No
crack Pass Pass Pass Pass Pass Pass Pass Pass Pass low temperature
bend test Check cable appearance and internal components for cracks - No
crack Pass Pass Pass Pass Pass Pass Pass Pass Pass Long-term DC insulation resistance
exam withstand voltage test - No
break down Pass Pass Pass Pass Pass Pass Pass Pass Pass Dynamic
Penetration
exam Insulation breaking strength
(Based on 150SQ) N 587
more 766 775 735 744 643 633 756 755 653 Flame Retardant
exam shot length mm 50 to 540 Pass Pass Pass Pass Pass Pass Pass Pass Pass smoke density
exam light transmittance % over 60 96 96 91 95 88 91 95 97 92

division unit baseline Example comparative example 3.1 3.2 3.3 3.4 3.5 3.6 3.1 3.2 3.3 Ozone resistance test Check the cable sheath appearance - No
crack Pass Pass Pass Pass Pass Pass Pass Pass Pass low temperature
Shock
exam Check cable appearance and internal components for cracks - No
crack Pass Pass Pass Pass Pass Pass Pass Pass Pass low temperature
bend test Check cable appearance and internal components for cracks - No
crack Pass Pass Pass Pass Pass Pass Pass Fail Pass Long-term DC insulation resistance
exam withstand voltage test - No
break down Pass Pass Pass Pass Pass Pass Pass Fail Pass Dynamic
Penetration
exam Insulation breaking strength
(Based on 150SQ) N 587
more 766 775 735 744 643 633 756 755 653 Flame Retardant
exam shot length mm 50 to 540 Pass Pass Pass Pass Pass Pass Fail Pass Fail smoke density
exam light transmittance % over 60 81 76 80 73 85 70 72 56 76

From the results of Tables 9 to 11, it can be confirmed that the sheath composition according to an exemplary embodiment of the present invention can satisfy all of the physical properties required as a cable when applied as an underwater solar cable used in a floating solar power system. can

Specifically, referring to Table 9, in the case of Comparative Examples 1.1 and 1.4, in which the content of the polyolefin resin grafted with the ethylene vinyl acetate resin and the polar moiety is not suitable, the reference values in the low-temperature bending test and the Dynamic Penetration test, respectively In the case of Comparative Example 1.2, where the content of the sheath composition components (crosslinking aid and crosslinking agent) other than the content of ethylene vinyl acetate resin and polyolefin resin grafted with a polar moiety was not suitable, low-temperature impact test and low-temperature bending It was confirmed that the standard value of the test item was not satisfied.

In addition, referring to Table 10, in the case of Comparative Examples 2.1 and 2.3, in which the content of other sheath composition components (antioxidant and UV stabilizer) in addition to the content of the polyolefin resin grafted with the ethylene vinyl acetate resin and the polar moiety was low, It was confirmed that the standard value of ozone test items was not satisfied.

In addition, referring to Table 11, in Comparative Examples 3.1 to 3.4, the content of other sheath composition components (inorganic metal-based flame retardant and phosphorus-based flame retardant) is not suitable in addition to the content of the polyolefin resin grafted with the ethylene vinyl acetate resin and the polar moiety. , low temperature bending test, long-term DC insulation resistance, dynamic penetration, flame retardancy test, and smoke density were found not to be satisfied.

Additionally, more specifically, in order to confirm whether the water-borne solar cable comprising the composition for a water-based solar cable sheath according to the present invention also satisfies the required water pressure and immersion evaluation, according to the Examples and Comparative Examples of Table 5 Including the sheath composition prepared in the composition and content ratio, but in the same manner as the above-described method for producing a water-based solar cable, each of the water-borne solar cables including the sheath composition was prepared, and the immersion evaluation was carried out by the following evaluation method .

[Additional test example] Immersion evaluation test

In accordance with HD (Harmonization Document) 22.16, the cables manufactured by each of the Examples and Comparative Examples in Table 5 were each stripped of the sheath and manufactured as a specimen according to the IEC 60811-501 standard. After that, the specimens were stored for 7 days at room temperature under 50%RH humidity conditions and pretreated, and then each specimen was immersed at 50°C for 100 days, and samples were collected every predetermined time to observe the changes in mass, tensile strength, and elongation. do.

The mass is measured after removing moisture from the surface and storing it for 16 hours at room temperature and 50%RH humidity.

The observed tensile strength and elongation must satisfy all of the following conditions.

1) The rate of change of tensile strength measured after 28 days and tensile strength measured after 100 days should be within ±15%.

2) The rate of change of elongation measured after 28 days and elongation measured after 100 days should be within ±20%.

The results of the immersion evaluation are shown in Tables 12 and 13 below.

division unit demand Example 3.1 3.2 3.3 3.4 3.5 3.6 Flooding
evaluation test
(50℃) 100 days later
mass change % <40 12 35 15 37 14 35 immersion 28 days Seal
burglar kgf/mm ² - 1.423 1.331 1.316 1.163 1.298 1.189 elongation % - 271.23 229.05 280.77 233.66 273.21 221.43 100 days of immersion Seal
burglar kgf/mm ² - 1.32132 1.17936 1.2188 1.026 1.20328 1.03892 elongation % - 234.50 190.88 245.31 199.14 241.90 180.71 Tensile strength change
(28 days ~ 100 days) % ≤±15 -7 -11 -7 -12 -7 -13 Elongation rate change (28 days ~ 100 days) % ≤±20 -14 -17 -13 -15 -11 -18

division unit demand comparative example 3.1 3.2 3.3 3.4 Flooding
evaluation test
(50℃) 100 days later
mass change % <40 11 45 8 43 immersion 28 days Seal
burglar kgf/mm ² - 1.454 1.242 1.416 1.108 elongation % - 279.79 209.19 292.77 199.19 100 days of immersion Seal
burglar kgf/mm ² - 1.368 1.0302 1.34592 0.90025 elongation % - 256.95 159.97 271.85 157.89 Tensile strength change
(28 days ~ 100 days) % ≤±15 -6 -17 -5 -19 Elongation rate change (28 days ~ 100 days) % ≤±20 -8 -24 -7 -21

From the results of Table 12, it was confirmed that the sheath composition according to an exemplary embodiment of the present invention can satisfy the immersion evaluation, which is a required major physical property, when applied as an underwater solar cable used in a floating photovoltaic system. .

However, referring to Table 13, if the components and content ratios of the sheath composition according to an embodiment of the present invention are not followed, it can be confirmed that the requirements of the immersion evaluation and the flame retardant test among the cable evaluation items are not satisfied. there was. More specifically, in Comparative Examples 3.2 and 3.4, in which excessive amounts of other sheath composition components (inorganic metal-based flame retardants and phosphorus-based flame retardants) were added in addition to the contents of the polyolefin resin grafted with the ethylene vinyl acetate resin and the polar moiety, the flame retardant test of the cable The evaluation can satisfy the requirements, but the change in mass after 100 days, the rate of change in tensile strength and the rate of change in tensile strength for 28 to 100 days after immersion among the submersion evaluation items do not satisfy the requirements, and ethylene vinyl acetate resin and polar moieties In Comparative Examples 3.1 and 3.3, in which the content of other sheath composition components (inorganic metal-based flame retardant and phosphorus-based flame retardant) other than the content of the grafted polyolefin resin was not sufficiently added, all of the submersion evaluation items may be satisfied, but in Table 11 above As confirmed, it was confirmed that it did not satisfy the requirements of the flame retardant test evaluation for the cable.

The above description of the present application is for illustration, and those of ordinary skill in the art to which the present application pertains will understand that it can be easily modified into other specific forms without changing the technical spirit or essential features of the present application. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive. For example, each component described as a single type may be implemented in a dispersed form, and likewise components described as distributed may be implemented in a combined form.

The scope of the present application is indicated by the following claims rather than the above detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included in the scope of the present application.

10: solar module
11: struct
12: buoyancy agent
13: anchor
14: weight
15: electrical room
16: KEPCO
20: conductor
21: insulating layer
100: underwater cable
200: sheath
300: floating solar cable

Claims (14)

ethylene vinyl acetate (EVA) resin; and
A polyolefin resin grafted with a polar moiety is included as a base resin,
Based on 100 parts by weight of the base resin,
In the composition for an aqueous solar cable sheath comprising 80 parts by weight to 153 parts by weight of a flame retardant,
The composition for the water-based solar cable sheath satisfies the following Equations 1 to 3, the composition for the water-based solar cable sheath:
[Formula 1]
A ≤ 40 (unit: %)
[Formula 2]
-15 ≤ ㅿTS ≤ 15 (Unit: %)
[Equation 3]
-20 ≤ ㅿE ≤ 20 (Unit: %)
In Equation 1, A is a dumbbell specimen prepared according to the IEC 60811-511 standard for a sheath separated from a water photovoltaic cable including a sheath layer prepared from the composition for a water photovoltaic cable sheath under 50% RH humidity. It refers to the rate of change of the mass of the dumbbell specimen measured after storage and pretreatment for 7 days, and then taking out the dumbbell specimen after maintaining immersion in a water bath at 50 ° C for 100 days compared to the mass of the measured dumbbell specimen, in Equation 2, ㅿTS is Dumbbell specimens prepared in accordance with IEC 60811-511 standards for the sheath separated from the water photovoltaic cable including the sheath layer prepared from the composition for the water photovoltaic cable sheath were stored for 7 days under 50% RH humidity and then pre-treated, It means the rate of change of tensile strength (ㅿTS100 - ㅿTS28 / ㅿTS28) measured after maintaining the immersion of the dumbbell specimen in a water bath at 50 ° C for 28 days (ㅿTS28) and 100 days (ㅿTS100), respectively, and the above formula In 3, ㅿE is a dumbbell specimen prepared according to the IEC 60811-511 standard for a sheath separated from a water photovoltaic cable including a sheath layer prepared from the composition for a water photovoltaic cable sheath, under 50% RH humidity for 7 days. After storage and pretreatment, the rate of change in elongation measured after maintaining the immersion in the dumbbell specimen for 28 days (ㅿE28) and 100 days (ㅿE100) in a water bath at 50°C (ㅿE100 - ㅿE28 / ㅿE28) it means.
The method of claim 1,
The base resin,
70 parts by weight to 90 parts by weight of ethylene vinyl acetate (EVA) resin; and
10 parts by weight to 30 parts by weight of a polar moiety grafted polyolefin resin; characterized in that it comprises, a composition for a water-borne solar cable sheath.
The method of claim 1,
The flame retardant is based on 100 parts by weight of the base resin,
80 parts by weight to 150 parts by weight of an inorganic metal-based flame retardant; and
0.5 parts by weight to 3 parts by weight of a phosphorus-based flame retardant; characterized in that it comprises, a composition for a water-borne solar cable sheath.
3. The method of claim 2,
The composition for a water photovoltaic cable sheath, characterized in that it satisfies the following Equation 4, the composition for a water photovoltaic cable sheath:
[Equation 4]
X ≥ 30 (unit: %)
In Equation 4, X is a dumbbell specimen prepared according to IEC 60811-501 standard for a sheath separated from a water photovoltaic cable including a sheath layer prepared from the composition for a water photovoltaic cable sheath, tension installed inside the low temperature chamber It means the low-temperature elongation measured at a tensile rate of 25±5 mm/min using a test facility.
The method of claim 1,
_{The melting temperature (T m} ) of the polyolefin resin grafted with the polar moiety is 50° C. to 90° C.
The method of claim 1,
The polyolefin resin grafted with the polar moiety is ethylene vinyl acetate grafted with maleic anhydride, the composition for a water-based solar cable sheath.
The method of claim 1,
The composition for the water photovoltaic cable sheath is based on 100 parts by weight of the base resin,
5 to 20 parts by weight of an antioxidant; and
5 to 10 parts by weight of a UV stabilizer or carbon black;
8. The method of claim 7,
The composition for a water photovoltaic cable sheath, characterized in that it satisfies all of the following Equations 5 to 7, the composition for a water photovoltaic cable sheath:
[Equation 5]
X ≥ 30 (unit: %)
[Equation 6]
Y ₁ ≥ 70 (unit: %)
[Equation 7]
Y ₂ ≥ 70 (unit: %)
In Equation 5, X is a dumbbell specimen prepared in accordance with IEC 60811-511 standards for a sheath separated from a water photovoltaic cable including a sheath layer prepared from the composition for a water photovoltaic cable sheath, tension installed inside a low temperature chamber It means a low-temperature elongation rate measured at a tensile rate of 25±5 mm/min using a test facility, and in Equation 6, Y ₁ is waterborne sunlight including a sheath layer prepared from the composition for the water-borne solar cable sheath. Dumbbell specimens prepared according to IEC 60811-501 standards of the sheath separated from the cables are put in a weathering test facility, exposed for 720 hours, and then taken out, and then the specimens are stored at 25±5℃, 50%RH for 18 hours, It means the residual tensile strength versus the tensile strength during the weather resistance/UV test measured at a tensile rate of 25±5 mm/min using a tensile test facility, and in Equation 7, Y ₂ is prepared from the composition for the water-borne solar cable sheath Dumbbell specimens prepared according to IEC 60811-501 standards of the sheath separated from the floating solar cable including the sheath layer were put in a weathering test facility, exposed for 720 hours, and then taken out, and the specimens were removed at 25±5℃, 50 It means the residual elongation compared to the elongation during the weather resistance/UV test measured at a tensile rate of 25±5 mm/min using a tensile test facility after storage at %RH for 18 hours.
8. The method of claim 7,
The composition for a water photovoltaic cable sheath, characterized in that it satisfies all of the following Equations 8 and 9, the composition for a water photovoltaic cable sheath:
[Equation 8]
Z ≥ 0.816 (Unit: kgf/mm ² )
[Equation 9]
T ≥ 120 (unit: ℃)
In Equation 8, Z is a dumbbell specimen prepared according to the IEC 60811-501 standard for a sheath separated from a water-based solar cable including a sheath layer prepared from the composition for a water-based solar cable sheath Extrusion and cross-linking process 16 hours Thereafter, it means the tensile strength among non-aging properties measured at a tensile rate of 250±50 mm/min using a tensile test facility, and in Equation 9, T is a sheath layer prepared from the composition for a water-based solar cable sheath. It means the Temperature Index calculated by selecting the end-point as 50% elongation based on IEC 60216-1 and IEC 62930 for a dumbbell specimen manufactured according to IEC 60811-511 standard of a sheath separated from a floating solar cable containing do.
The method of claim 1,
The composition for the water photovoltaic cable sheath is based on 100 parts by weight of the base resin,
2 to 10 parts by weight of a crosslinking agent; and
0.5 parts by weight to 3 parts by weight of a crosslinking aid, characterized in that it further comprises, the composition for a water-based solar cable sheath.
11. The method of claim 10,
The composition for a water photovoltaic cable sheath, characterized in that it satisfies all of the following Equations 10 to 12, the composition for a water photovoltaic cable sheath:
[Equation 10]
E ₁ ≥ 125 (Unit: %)
[Equation 11]
E ₂ ≥ 100 (unit: %)
[Equation 12]
X ≥ 30 (unit: %)
In Equation 10, E ₁ is the extruding and crosslinking process of a dumbbell specimen prepared according to IEC 60811-501 standards for a sheath separated from a water photovoltaic cable including a sheath layer prepared from the composition for a water photovoltaic cable sheath. After time, it means the elongation rate among the non-aging properties measured at a tensile rate of 250±50 mm/min using a tensile test facility, and in Equation 11, E ₂ is the sheath prepared from the composition for the water-borne solar cable sheath. Dumbbell specimens prepared according to the IEC 60811-511 standard of the sheath separated from the floating solar cable including the layer were placed in a base solution (N-Sodium hydroxide, 1N, 23±2℃) according to the IEC 60811-404 standard for 168 hours. It means the elongation rate in the base resistance measured at a tensile rate of 250±50 mm/min using a tensile test facility after putting it in for a while and then taking it out, and in Equation 12, X is the sheath prepared from the composition for the water photovoltaic cable sheath. Low-temperature elongation measured at a tensile rate of 25±5 mm/min using a tensile test facility installed inside a low-temperature chamber on a dumbbell specimen manufactured in accordance with IEC 60811-501 of a sheath separated from a floating solar cable including a layer means
11. The method of claim 10,
The composition for a water photovoltaic cable sheath, characterized in that it satisfies all of the following Equations 13 to 15, the composition for a water photovoltaic cable sheath:
[Equation 13]
Z ≥ 0.816 (Unit: kgf/mm ² )
[Equation 14]
-30 ≤ △E ≤ +30 (Unit: %)
[Equation 15]
H ≤ 100 (unit: %)
In Equation 13, Z is a dumbbell specimen prepared according to the IEC 60811-501 standard for a sheath separated from a water-based solar cable including a sheath layer prepared from the composition for a water-based solar cable sheath Extrusion and cross-linking process 16 hours After that, it means the tensile strength among the non-aging properties measured at a tensile rate of 250±50 mm/min using a tensile test facility, and in Equation 14, ΔE is the sheath prepared from the composition for the water-borne solar cable sheath. Dumbbell specimens prepared according to the IEC 60811-511 standard of the sheath separated from the floating solar cable including the layer were placed in an acid solution (N-Oxalic Acid, 1N, 23±2℃) according to the IEC 60811-404 standard for 168 hours. It means the rate of change compared to the tensile strength in acid resistance measured at a tensile rate of 250±50 mm/min using a tensile test facility after putting it in for a while, and in Equation 15, H is from the composition for the water solar cable sheath. Dumbbell specimens manufactured according to the IEC 60811-501 standard for the sheath separated from the floating photovoltaic cable including the manufactured sheath layer were marked at intervals of 20 mm in the middle, and then placed on the specimen in a chamber at a temperature of 200±3℃. It refers to the rate of change (Hot) measured by hanging a load (weight) of 20.4N/cm ² (based on the cross-sectional area) and exposing it for 15 minutes, and then measuring the extended length (marked interval).
conductor;
an insulating layer provided to surround the outer periphery of the conductor; and
A waterborne solar cable comprising a sheath layer made from the composition for a waterborne solar cable sheath according to any one of claims 1 to 12.
14. The method of claim 13,
The water photovoltaic cable, characterized in that it satisfies the following Equation 16, water photovoltaic cable:
[Equation 16]
50 ≤ L ≤ 540 (unit: mm)
In Equation 16, L is the digested length in the flame retardant test measured in accordance with the IEC 60332-1-2 standard for the cable specimen by making a specimen 16 hours or more after the crosslinking process is completed in the finished product of the water photovoltaic cable. means

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