WO2012005357A1

WO2012005357A1 - Photovoltaic power collection cable

Info

Publication number: WO2012005357A1
Application number: PCT/JP2011/065709
Authority: WO
Inventors: 丈八木澤; 智山崎
Original assignee: 住友電気工業株式会社
Priority date: 2010-07-08
Filing date: 2011-07-08
Publication date: 2012-01-12
Also published as: JP2012018830A; CN102483974A; CN102483974B

Abstract

Provided is a photovoltaic power collection cable which satisfies the physical characteristics (elongation, tensile strength, and retentions of elongation and tensile strength after aging), thermal deformation resistance and flame retardance as stipulated in PSE standards for the sheath. Even when scratched, the photovoltaic power collection cable does not suffer from whitening and thus has excellent surface appearance. A photovoltaic power collection cable (1) configured in such a manner that a conductor (10) is covered with an insulation layer of double wall structure which comprises both an outer insulation layer (30) and an inner insulation layer (20) made of polyethylene, wherein the outer insulation layer (30) comprises synthetic magnesium hydroxide (A) and a base resin (B) at an (A)/(B) mass ratio of 1 to 1.6, and the base resin comprises a polyolefin resin (C) and a styrenic thermoplastic elastomer (D) at a (C)/(D) mass ratio of 70/30 to 90/10, said polyolefin resin (C) comprising a polypropylene resin (E) and an ethylene/ethyl acrylate copolymer (F) at an (E)/(F) mass ratio of 2/6 to 3/5.

Description

Solar collector cable

The present invention relates to a solar current collecting cable, and more particularly to a solar current collecting cable covered with an insulating layer having a two-layer structure.

In recent years, the development of clean energy has been demanded due to the growing interest in environmental issues and energy issues such as depletion of energy resources and increased CO ₂ in the atmosphere. In particular, solar power generation systems using solar cells Is being put to practical use as a new energy source.
Since a solar current collecting cable used in such a photovoltaic power generation system is assumed to be used in an outdoor environment, in addition to the wide usable temperature, UV resistance, flexibility, mechanical strength, It is required to be heavy insulation or reinforced insulation, and the solar collector cable is also required to be a cable that complies with the Electrical Appliance and Material Safety Law (PSE standard).

In addition to the requirements for conductors and insulators, the PSE standard requires physical properties (elongation, tensile strength, residual elongation ratio after aging and residual tensile strength ratio) and heat deformation in addition to the requirements for the sheath (sheath). There are items to prescribe. Furthermore, in order to prevent the fire from spreading through the cable in the event of a fire accident, the PSE standard requires flame retardancy.
As a flame-retardant electric wire, there is a non-halogen flame-retardant electric wire described in Patent Document 1.

Japanese Unexamined Patent Publication No. 2001-160324

However, in these cables, it is necessary to mix a metal oxide such as aluminum hydroxide or magnesium hydroxide in the outer layer in order to realize the above flame retardancy, and the cable containing this metal oxide was rubbed. There is a problem that the appearance becomes poor because a phenomenon that the portion becomes white sometimes, so-called whitening occurs.

The present invention has been made by paying attention to the above-mentioned problems in conventional solar current collecting cables, and its purpose is to provide physical properties (elongation, tensile strength, aging after aging) required for the jacket according to the PSE standard. An object of the present invention is to provide a solar power collecting cable that has a good appearance that does not cause so-called whitening due to rubbing or the like while satisfying elongation residual ratio and tensile strength residual ratio), heat deformability, and flame retardancy.

As a result of intensive studies to achieve the above-mentioned object, the inventors of the present invention incorporated a synthetic magnesium hydroxide into a resin constituting the outer insulating layer at a certain ratio in a cable in which a conductor is double-coated with an insulating layer. And it discovered that the said objective can be achieved by making the composition of resin which comprises an outer side insulating layer into a specific thing, and came to complete this invention.

That is, the solar collector cable of the present invention is a solar collector cable in which a conductor is coated with an insulating layer having a two-layer structure including an outer insulating layer and an inner insulating layer made of polyethylene, The insulating layer contains synthetic magnesium hydroxide (A) and base resin (B) in a mass ratio of (A) / (B) = 1 to 1.6, and the base resin is a polyolefin resin (C) And styrene-based thermoplastic elastomer (D) in a mass ratio of (C) / (D) = 70/30 to 90/10, and the polyolefin-based resin is a polypropylene-based resin (E) and ethylene-acrylic acid The ethyl copolymer (F) is contained in a mass ratio of (E) / (F) = 2/6 to 3/5.

In the solar current collecting cable of the present invention, it is preferable that the styrenic thermoplastic elastomer is SEBS (styrene-ethylenebutylene-styrene copolymer).

It is a general | schematic cross-section perspective view which shows an example of the solar collector cable of this invention.

Hereinafter, the solar current collecting cable of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic cross-sectional perspective view showing an example of the solar current collecting cable of the present invention.
The solar collector cable 1 has a shape in which the conductor 10 is covered with a double-structured insulating layer including an inner insulating layer 20 and an outer insulating layer 30 laminated on the outer periphery thereof. In the solar power generation system, one having a length of about 1.5 m is usually used as a set of two.

The size of the conductor 10 is preferably a cross-sectional area of 2.0 to 6.0 mm ² , and considering the PSE standard, the nominal cross-sectional area is 2.0 mm ² and 3.5 mm ² , and the configuration is 7 strands. / The strand diameter is preferably 0.6 mm, 7 strands / strand diameter is preferably 0.8 mm. The material can be, for example, annealed copper.

In consideration of the PSE standard, the inner insulating layer 20 preferably has a thickness of 0.7 to 1.2 mm and an outer diameter of 3.4 to 5.1 mm. The material of the inner insulating layer 20 is polyethylene. By making the inner insulating layer 20 pure polyethylene, good electrical characteristics can be realized.

In consideration of the PSE standard, the outer insulating layer 30 preferably has a thickness of 1.5 mm and a finished outer diameter of 6.4 to 8.1 mm.

The outer insulating layer 30 contains synthetic magnesium hydroxide as a flame retardant. Examples of commercially available synthetic magnesium hydroxide include Kisuma (trademark) manufactured by Kyowa Chemical Industry Co., Ltd. Here, the reason why the flame retardant is limited to the synthetic magnesium hydroxide is that the flame retardancy can be realized without causing whitening when the cable is rubbed by adding the flame retardant to a specific content ratio. The synthetic magnesium hydroxide may be surface-treated. On the other hand, normally used metal oxides such as aluminum hydroxide and natural magnesium hydroxide are effective for obtaining flame retardancy, but when an amount capable of obtaining flame retardancy is added, the abrasion point of the cable Since it becomes white, it is impossible to achieve both flame retardancy and good appearance.
The synthetic magnesium hydroxide is contained at a mass ratio of 1 to 1.6 with respect to the base resin of the outer insulating layer 30. If it is less than 1, the desired flame retardancy cannot be obtained, and if it exceeds 1.6, the extrudability during molding deteriorates.

The base resin of the outer insulating layer 30 contains a polyolefin resin (C) and a styrene thermoplastic elastomer (D). The mass ratio is (C) / (D) = 70/30 to 90/10. When the content ratio of the polyolefin resin exceeds 90% by mass of the total amount of the polyolefin resin and the styrene thermoplastic elastomer, the flame retardancy tends to be inferior and a desired tensile strength cannot be obtained. On the other hand, when the content is less than 70% by mass, the outer insulating layer 30 is whitened.

The polyolefin resin contains a polypropylene resin (E) and an ethylene-ethyl acrylate copolymer (F) in a mass ratio of (E) / (F) = 2/6 to 3/5. If the content ratio of the polypropylene resin is less than 2/8 of the total amount of the polypropylene resin and the ethylene-ethyl acrylate copolymer, the desired tensile strength cannot be obtained. It will be inferior in growth.
The polypropylene-based resin is not particularly limited, but an ethylene-propylene copolymer or polypropylene obtained by melt-kneading ethylene-propylene rubber (EPDM, EPR) is preferable. Particularly preferred is an ethylene propylene copolymer obtained by melt-kneading EPDM or EPR. This is because flexibility that facilitates work during wiring can be provided while having sufficient heat resistance and strength. As the polypropylene resin, a reactor TPO type can be used in addition to the compound TPO type (TPO: olefinic thermoplastic elastomer) synthesized by melt-kneading the resin component and the rubber component as described above. Reactor TPO is an olefinic thermoplastic elastomer in which a rubber component, which is a soft part, is dispersed in a matrix resin, which is a hard part, during polymer polymerization, and a compound TPO that is synthesized by melting and kneading the above resin component and rubber component. Thus, the resin component and the rubber component are polymerized in the same polymerization field to obtain TPO. In the present invention, a matrix part having polypropylene can be used.

The styrene-based thermoplastic elastomer is not particularly limited, but is preferably SEBS (styrene-ethylenebutylene-styrene copolymer) or SEBC (styrene-ethylenebutylene-olefin crystal block copolymer). By containing an aromatic ring of a styrene component, the shell-making property at the time of combustion is improved and it becomes easy to pass the flame retardant test. Also, since it has an ethylene-butadiene component, it does not deteriorate the elongation and strength of the polyolefin resin when mixed with the polyolefin resin, and the tensile strength can be improved as compared with the case where the polyolefin resin is used alone. it can.

The ethylene-ethyl acrylate copolymer is not particularly limited, but preferably has an ethyl acrylate content of 10 to 25% by mass, and an ethyl acrylate content of about 15% by mass. Is particularly preferred. This is because the dispersibility of magnesium hydroxide is improved. When the content of ethyl acrylate is small, magnesium hydroxide cannot be sufficiently dispersed, and elongation cannot be obtained, and aggregation of magnesium hydroxide occurs.

The base resin of the outer insulating layer 30 may further include a plasticizer, an ultraviolet absorber, a light stabilizer, an anti-aging agent, a lubricant, a colorant, a filler, a processability improver, and other modifiers as necessary. It can also be used individually or in combination of 2 or more types.

The solar collector cable 1 is obtained by covering the conductor 10 in the order of the inner insulating layer 20 and the outer insulating layer 30 by extrusion coating. The polyethylene used for the inner insulating layer 20 is preferably crosslinked by a method such as electron beam or ultraviolet irradiation.
In the extrusion coating, the respective compositions are kneaded with a roll, a banbury, an extruder, etc., and the obtained pellet compound and conductor are subjected to wire coating extrusion molding with a conventionally known wire extruder provided with a crosshead die. It can be done by things.

Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited to these examples.

(1) Manufacture of solar collector cables Solar collector cables of Examples 1 to 5 and Comparative Examples 1 to 6 using jackets having the compositions shown in Table 1 as outer insulating layers were prepared. For each cable, two types of cables (cables 1 and 2) having different finished outer diameters shown in Table 2 were produced.

(2) Evaluation of produced solar collector cable Table 1 shows the obtained cables and evaluation. It should be noted that in all of Examples 1 to 5 and Comparative Examples 1 to 6, the same result is obtained with cables (cables 1 and 2) having different finished outer diameters.

The evaluation methods for various characteristics performed on the solar current collecting cables in the above examples are as follows.

[Flame retardant test]
Flame retardancy was evaluated by 60 ° tilted flame retardancy.
About 60 degree inclination flame-retardant, the flame was applied to the cable for 30 seconds, the flame was removed immediately after ignition, and the case where it disappeared within 60 seconds was set as the pass.

[Extension of outer cover]
The outer insulating layer portion was taken out from the cable and measured according to JIS C3005: 2000 4.16. The test machine specified in JIS B 7721 was used. A tubular test piece was attached to the chuck of the testing machine, and the pulling speed was 200 mm / min. The length between the marked lines at the time of cutting and cutting was measured, and the elongation was calculated by the following formula. The test was performed at room temperature and judged with n = 3.
(Expression) ε = (l ₁ −l ₀ / l ₀ ) × 100
In the above formula, ε is elongation (%), l ₁ is the length between marked lines (mm) at the time of cutting, and l ₀ is the length (mm) between marked lines.

[Residual growth rate after aging of jacket]
For the outer insulating layer taken out from the cable, the elongation was measured and calculated after aging (90 ° C. × 4 days), and the residual ratio exceeded 65% compared with the elongation before aging was regarded as acceptable. The residual rate was calculated by the following formula, and was determined by n = 3.
(Formula) X = (C ₁ / C ₀ ) × 100
In the above formula, X is a residual rate (%), C ₁ is a value after aging, and C ₀ is an average value before aging.

[Strength of jacket]
The outer insulating layer portion was taken out from the cable and measured according to JIS C3005: 2000 4.16. The test machine specified in JIS B 7721 was used. A tubular test piece was attached to the chuck of the testing machine, and the pulling speed was 200 mm / min. The tensile strength was measured by the following formula, and the tensile strength was calculated by the following formula. The test was performed at room temperature and judged with n = 3.
(Formula) δ = F / A
In the above formula, δ is the tensile strength (MPa), F is the maximum tensile load (N), and A is the cross-sectional area (mm ² ) of the test piece.

[Residual tensile strength after aging of jacket]
For the outer insulating layer taken out from the cable, the tensile strength was measured and calculated after aging (90 ° C. × 4 days), and the residual ratio exceeded 80% compared with the tensile strength before aging. In calculating the tensile strength, the cross-sectional area of the test piece was the value before aging. Further, the remaining rate was calculated by the following equation, and the determination was made with n = 3.
(Formula) X = (C ₁ / C ₀ ) × 100
In the above formula, X is a residual rate (%), C ₁ is a value after aging, and C ₀ is an average value before aging.

[Heat deformation of jacket]
The cable was cut into a length of 30 mm, and the lead wire and the inner insulating layer were removed to obtain a tubular test piece of the outer insulating layer. The tubular test piece was measured for heat deformation according to JISC3005: 2000 4.23 at a heating temperature of 75 ° C. and a load of 1 kg. Those with a remaining rate exceeding 90% were regarded as acceptable. The determination was made at n = 3.

[Presence of whitening]
A cable was manufactured and wound on a bobbin. The bobbin body was pulled out, and 10 m was visually observed as a bundle to find a whitened portion. No whitening was observed (OK) when there was one whitening spot per 1 m or where no whitening was observed. The thing where the whitening part exceeding it was observed was made into whitening (NG).

[Evaluation considerations]
Examples 1 to 4 are physical properties (elongation, tensile strength, residual elongation rate after tensile aging and residual tensile strength rate) required for the jacket according to the PSE standard, heat distortion, flame retardancy, and good appearance characteristics that do not cause whitening. Good results excellent in any of the above can be obtained.

In Comparative Examples 1 and 2, since natural magnesium hydroxide was used, whitening occurred. Furthermore, about Comparative Example 2, since homopolypropylene was used as the polypropylene-based resin, the result was that the elongation was inferior together with flame retardancy compared to Comparative Example 1 using the ethylene-propylene block copolymer.
Since Comparative Example 3 does not contain SEBS, which is a styrenic thermoplastic elastomer, no tensile strength can be obtained. On the other hand, if SEBS, which is a styrenic thermoplastic elastomer, is added too much as in Comparative Example 4, whitening occurs. Although Comparative Example 3 does not contain SEBS, which is a styrene thermoplastic elastomer, flame retardant is a problem because the blending ratio of the polypropylene resin and the ethylene-ethyl acrylate copolymer in the polyolefin resin is good. There is no level.
Comparative Examples 5 and 6 are experimental examples in which the blending ratio of the polypropylene resin and the ethylene-ethyl acrylate copolymer in the polyolefin resin was changed. In Comparative Example 5 containing a polypropylene resin exceeding a specific ratio, While the flame retardancy is inferior and the elongation is poor, Comparative Example 6 containing an ethylene-ethyl acrylate copolymer in excess of the specific ratio results in inferior tensile strength.

Further, in Comparative Examples 1 to 6, several (about 5) whitening portions were observed per 1 m. When the cables are wound, the cables are rubbed with each other or the cables are rubbed with the guide roller, and white streaks (length of several centimeters) may be attached to the cable.

According to the present invention, the conductor is covered with an insulating layer having a two-layer structure including an outer insulating layer and an inner insulating layer made of polyethylene, and the outer insulating layer is made of synthetic magnesium hydroxide (A) and a base resin ( B) is contained in a mass ratio of (A) / (B) = 1 to 1.6, and the base resin comprises a polyolefin resin (C) and a styrene thermoplastic elastomer (D) (C) / (D) = 70/30 to 90/10 in a mass ratio, and the polyolefin resin comprises a polypropylene resin (E) and an ethylene-ethyl acrylate copolymer (F) (E) / (F ) = 2/6 to 3/5 in a mass ratio, physical properties (elongation, tensile strength, residual elongation rate after tensile aging and residual tensile strength rate) and heat deformability required for the jacket according to PSE standards, So-called whitening due to scratching does not occur while satisfying flame retardancy It is possible to provide a solar collector cable having a good appearance.

DESCRIPTION OF SYMBOLS 1 ... Solar collector cable, 10 ... Conductor, 20 ... Inner insulating layer, 30 ... Outer insulating layer.

Although the invention has been described in detail with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.
Note that this application is based on a Japanese patent application filed on July 8, 2010 (Japanese Patent Application No. 2010-155766), which is incorporated by reference in its entirety. Also, all references cited herein are incorporated as a whole.

Claims

A solar collector cable in which a conductor is coated with an insulating layer having a two-layer structure including an outer insulating layer and an inner insulating layer made of polyethylene,
The outer insulating layer contains synthetic magnesium hydroxide (A) and base resin (B) in a mass ratio of (A) / (B) = 1 to 1.6,
The base resin contains a polyolefin resin (C) and a styrene thermoplastic elastomer (D) in a mass ratio of (C) / (D) = 70/30 to 90/10,
The solar radiation collection in which the polyolefin resin contains a polypropylene resin (E) and an ethylene-ethyl acrylate copolymer (F) in a mass ratio of (E) / (F) = 2/6 to 3/5 Electric cable.
The solar power collecting cable according to claim 1, wherein the styrenic thermoplastic elastomer is SEBS (styrene-ethylenebutylene-styrene copolymer).