JP5570880B2 - Power supply cable - Google Patents

Description

  The present invention relates to a power supply cable used in a solar power generation system or the like.

  As a solar power generation system, one that generates power using a plurality of solar cell modules laid in a matrix on the roof of a building is known. In such a solar power generation system, in order to take out the electric power generated by each solar cell module, adjacent solar cell modules are electrically connected by a cable (for example, refer to Patent Document 1). The cable connecting the solar cell modules is generally called a photovoltaic power supply system power supply cable or a photovoltaic power generation cable. Conventionally, an insulator made of cross-linked polyethylene on a copper stranded conductor, and a difficulty A cable in which a sheath made of flame-retardant polyethylene or flame-retardant crosslinked polyethylene is provided in order is used.

  However, the conventional cable does not necessarily have the characteristics required for the power supply cable for the photovoltaic power generation system, and in particular, the heat resistance and the heat life characteristics are insufficient. In other words, since the cable for feeding the photovoltaic power generation system is exposed to the sun for a long time, the temperature rise is large, and this high temperature state continues for a long time. Further, the temperature rise and fall by the sun is long. Repeated over a period of time. For this reason, extremely strict heat resistance and heat-resistant life characteristics are required, but conventional cables cannot sufficiently meet such strict requirements.

JP 2007-115915 A

  The present invention has been made in response to the above-described problems of the prior art, and an object of the present invention is to provide a power supply cable having excellent heat resistance and heat life characteristics that can be sufficiently used for applications of a photovoltaic power generation system. .

The power supply cable according to the first aspect of the present invention is a power supply cable including an insulator and a sheath in order on the outer periphery of the conductor, wherein the insulator is linear low-density polyethylene and / or ethylene.・ Ethyl acrylate copolymer as a base polymer, hindered phenolic antioxidant 0.30 to 0.70 mass%, sulfur antioxidant 0.10 to 0.50 mass%, and hindered amine light stability An insulating resin composition containing 0.05 to 0.35% by mass of an agent is coated on the outer periphery of the conductor and crosslinked by electron beam irradiation.

  According to a second aspect of the present invention, in the power supply cable according to the first aspect, the insulating resin composition includes a hindered phenol-based antioxidant 0.55 to 0.65% by mass, a sulfur-based antioxidant. It contains 0.25 to 0.45 mass% and hindered amine light stabilizer 0.05 to 0.25 mass%.

  According to a third aspect of the present invention, in the power supply cable according to the first aspect or the second aspect, the hindered phenol-based antioxidant is pentaerythritol tetrakis [3- (3,5-di-t- Butyl-4-hydroxyphenyl) propionate] and the sulfur-based antioxidant includes pentaerythritol tetrakis (β-lauryl-thiopropionate).

A fourth aspect of the present invention, in the power supply cable is any of the first aspect to third aspect, the insulator is a der shall oxidation induction period than 5 minutes at 240 ° C. is there.

According to a fifth aspect of the present invention, in the power supply cable according to any one of the first to fourth aspects, the power generation cable is a solar power generation system power supply cable.

  According to the power feeding cable of the present invention, it is possible to provide excellent heat resistance and heat resistance life characteristics that can be sufficiently used for applications of a solar power generation system.

It is a perspective view which shows the cable for electric power feeding which concerns on one Embodiment of this invention.

  Embodiments of the present invention will be described below.

  First, the insulating resin composition used for the power feeding cable of the present invention will be described.

  The insulating resin composition used in the present invention comprises a polyolefin as a base polymer, and contains a hindered phenol-based antioxidant, a sulfur-based antioxidant, and a hindered amine-based light stabilizer.

  Examples of the base polymer polyolefin include polyethylene such as low density polyethylene (LDPE), medium density polyethylene (MDPE), high density polyethylene (HDPE), very low density polyethylene (VLDPE), and linear low density polyethylene (LLDPE). Polypropylene (PP); polyisobutylene; ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, Ethylene / α-olefin copolymerized with α-olefin such as 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-nonadecene, 1-eicocene, 4-methyl-1-pentene Copolymer; ethylene, vinyl acetate, propylene Ethylene / vinyl ester copolymer obtained by copolymerization of vinyl esters such as vinyl onate, vinyl butyrate, vinyl persicate, vinyl laurate, vinyl stearate, vinyl benzoate, vinyl salicylate, vinyl cyclohexanecarboxylate; , Methyl acrylate, ethyl acrylate, isopropyl acrylate, isobutyl acrylate, n-butyl acrylate, isooctyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, isobutyl acrylate, dimethyl maleate, Examples thereof include an ethylene / acrylic acid ester copolymer obtained by copolymerizing an unsaturated carboxylic acid ester such as diethyl maleate; an isobutylene / isoprene copolymer. As the polypropylene, not only a homopolymer of propylene, but also a random copolymer or block copolymer with ethylene, a copolymer with a small amount of α-olefin, and the like can be used. Examples of the α-olefin include 1-butene, 1-pentene, 1-hexene, 1-octene, 4-methyl-1-pentene and the like. A non-conjugated polyene may be further copolymerized with the propylene / α-olefin copolymer. Examples of the non-conjugated polyene include dicyclopentadiene, 1,4-hexadiene, ethylidene norbornene, and vinyl norbornene. These may be used individually by 1 type and may be used in combination of 2 or more type.

  Polyolefin is generally used as a cable coating material, and low-density polyethylene, linear low-density polyethylene, and ethylene / ethyl acrylate copolymer are preferred because they are easy to recycle. From the viewpoint of superiority, linear low density polyethylene and ethylene / ethyl acrylate copolymer are more preferable.

  In the insulating resin composition used in the present invention, a hindered phenol-based antioxidant and a sulfur-based antioxidant are used in combination as an antioxidant, and a hindered amine-based light stabilizer is used as a light stabilizer. Is done.

  Any hindered phenol-based antioxidant can be used without particular limitation as long as it has a 3,5-di-t-butyl-4-hydroxybenzyl group. Specifically, for example, pentaerythritol tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], tetrakis [methylene-3- (3,5-di-t-butyl-4) -Hydroxyphenyl) propionate] methane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, 1,6-hexanediol-bis ( 3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 1,3,5-tris ( 3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate, isooctyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) Lopionate, etc. are used, and these may be used alone or in admixture of two or more. Pentaerythritol tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] is preferable from the viewpoint of superiority.As a commercially available product of this compound, for example, IRGANOX 1010 (trade name) manufactured by BASF Is mentioned.

  This hindered phenol-based antioxidant is blended in the insulating resin composition in an amount of 0.30 to 0.70% by mass, preferably 0.55 to 0.65% by mass. If the amount of the hindered phenol-based antioxidant is less than 0.30% by mass, the heat resistance and heat-resistant life characteristics become insufficient, and if it exceeds 0.70% by mass, the surface of the insulator may be bloomed.

  The sulfur-based antioxidant is not particularly limited as long as it is an antioxidant having a sulfur atom in the molecular skeleton. Specifically, for example, pentaerythritol tetrakis (β-lauryl-thiopropionate), dilauryl-3,3′-thiodipropionate, 4,4′-thiobis (6-t-butyl-3-methylphenol) ), Dimyristyl-3,3'-thiodipropionate, distearyl-3,3'-thiodipropionate, bis [2-methyl-4- (3-n-alkylthiopropionyloxy) 5-t-butylphenyl Sulfide, 2-mercaptobenzimidazole, zinc salt of 2-mercaptobenzimidazole, 2-mercaptomethylbenzimidazole, zinc salt of 2-mercaptomethylbenzimidazole, dioctadecyl sulfide and the like are used. These may be used individually by 1 type, and may mix and use 2 or more types. Among them, pentaerythritol tetrakis (β-lauryl-thiopropionate) is preferable because it is excellent in heat resistance and heat-resistant lifetime characteristics. As a commercial item of this compound, ADK STAB AO-412S (trade name) manufactured by ADEKA Corporation is exemplified.

  This sulfur-based antioxidant is blended in the insulating resin composition at 0.10 to 0.50 mass%, preferably 0.25 to 0.45 mass%. If the amount of the sulfur-based antioxidant is less than 0.10% by mass, the heat resistance and heat-resistant life characteristics are insufficient, and if it exceeds 0.50% by mass, the surface of the insulator may be bloomed.

  In the insulating resin composition, an antioxidant other than the hindered phenol-based antioxidant and the sulfur-based antioxidant can be blended within a range that does not impair the effects of the present invention. Examples of such antioxidants include 2,6-di-t-butyl-p-cresol, 2-t-butyl-4,6-dimethylphenol, 2,6-di-t-butyl-4- Phenolic antioxidants other than hindered phenols such as ethylphenol; heavy metals such as 2 ', 3-bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyl] propionohydrazide Activating agents: phosphorus antioxidants such as triphenyl phosphite and tris (2-ethylhexyl) phosphite, amine antioxidants such as alkylated diphenylamine and 4,4'-bis (α, α-dimethylbenzyl) diphenylamine Examples thereof include agents.

  On the other hand, examples of the hindered amine light stabilizer include dimethyl succinate-1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethylpiperidine polycondensate, bis (2,2, 6,6-tetramethyl-4-piperidyl) sebacate, 4-benzoyloxy-2,2,6,6-tetramethylpiperidine, poly [(6-morpholino-s-triazine-2,4-diyl) [2, 2,6,6-tetramethyl-4-piperidyl] imino]], dibutylamine, 1,3,5-triazine, N, N′-bis (2,2,6,6-tetramethyl-4-piperidyl- 1,6-hexamethylenediamine and N- (2,2,6,6-tetramethyl-4-piperidyl) butylamine polycondensate, poly [{6- (1,1,3,3-tetramethylbutyl) A -1,3,5-triazine-2,4-diyl} {(2,2,6,6-tetramethyl-4-piperidyl) imino} hexamethylene {(2,2,6,6-tetramethyl- 4-piperidyl) imino}], bis (1,2,2,6,6-pentamethyl-4-piperidyl) [[3,5-bis (1,1-dimethylethyl) -4-hydroxyphenyl] methyl] Butyl malonate etc. are used, These may be used individually by 1 type, and 2 or more types may be mixed and used as a hindered amine light stabilizer especially in heat-resistant lifetime characteristics. NOR type hindered amine light stabilizers are preferable from the viewpoint of superiority.Examples of commercially available light stabilizers containing this compound include Chimassorb 2020 and TINUVIN XT 855F manufactured by BASF (above, Name), and the like.

  When a hindered amine light stabilizer is used in combination with the above hindered phenol antioxidant and sulfur antioxidant, the insulating resin composition is irradiated with an electron beam and crosslinked with an electron beam. Deterioration of the inhibitor is suppressed or prevented. As a result, the antioxidant effect by the antioxidant is sufficiently exhibited, and the heat resistance and heat resistance life characteristics of the insulating resin composition can be improved.

  In order to effectively exhibit such an effect, the hindered amine light stabilizer needs to be blended in an amount of 0.05 to 0.35% by mass in the insulating resin composition, and preferably 0.05 to 0. 25% by mass. When the amount of the hindered amine light stabilizer is less than 0.05% by mass, the above effects cannot be obtained and the heat resistance and heat-resistant life characteristics become insufficient. When the amount exceeds 0.35% by mass, the insulator surface blooms. There is a fear.

  In the insulating resin composition, a light stabilizer other than the hindered amine light stabilizer can be blended within a range that does not impair the effects of the present invention. Examples of such a light stabilizer include 2- (2′-hydroxy-4′-n-octoxyphenyl) bezotriazole, 2,4-di-t-butylphenyl-3,5-di-t. UV absorbers such as butyl-4-hydroxybenzoate are exemplified.

  In addition to the above components, the insulating resin composition of the present embodiment further includes a plasticizer, a softening agent, a copper damage inhibitor, a filler, and a processing aid, as necessary, as long as the effects of the present invention are not impaired. Additives such as lubricants, colorants, stabilizers, flame retardants and flame retardant aids can be blended.

  Examples of the filler include fused silica, crystalline silica, alumina, zirconia, talc, clay, mica, calcium carbonate, titanium white, bengara, silicon carbide, boron nitride, silicon nitride, and aluminum nitride.

  Examples of processing aids include ricinoleic acid, stearic acid, palmitic acid, lauric acid, and salts or esters thereof.

  Examples of the lubricant include hydrocarbons, fatty acids, fatty acid amides, esters, and alcohols.

  Flame retardants include metal hydroxides such as magnesium hydroxide, aluminum hydroxide and calcium hydroxide, nitrogen flame retardants such as guanidine and melamine, phosphorus flame retardants such as ammonium phosphate and red phosphorus, phosphorus- Examples thereof include nitrogen flame retardants, boric acid compounds such as zinc borate, and calcium carbonate.

  Each of the above additives may be used alone or in combination of two or more.

  The insulating resin composition used in the present invention includes the polyolefin, the hindered phenol antioxidant, the sulfur antioxidant, the hindered amine light stabilizer, and the above-described blended as necessary. The various components thus prepared can be easily prepared by uniformly mixing them using an ordinary kneader such as a Banbury mixer, tumbler, pressure kneader, kneading extruder, mixing roller or the like.

  In the power supply cable of the present invention, the insulating composition is formed by coating the insulating composition directly or through another coating on the outer periphery of the conductor, or by winding a tape-shaped one to form an insulator. It is manufactured by forming a sheath on the outer periphery by a conventional method. The insulating resin composition is crosslinked by irradiation with an electron beam after coating or molding. The degree of crosslinking is preferably 70% or more, more preferably 80% or more in terms of gel fraction. When the gel fraction is less than 70%, the heat resistance and heat resistance life characteristics cannot be sufficiently improved. This gel fraction is measured based on the crosslinking degree test method specified in JIS C 3005.

Hereinafter, the power supply cable of the present invention using the insulating resin composition will be described.
FIG. 1 is a perspective view showing an embodiment of a power supply cable according to the present invention.
In FIG. 1, the code | symbol 1 has shown the conductor which consists of 1 thru | or several tin plating annealed copper wire. The conductor 1 has a cross-sectional area of e.g. 2.5-4.0 ^2. On this conductor 1, the insulator 2 having a thickness of, for example, 1.0 to 1.5 mm is formed by extrusion-coating the insulating resin composition described above and crosslinking by irradiation with an electron beam. A sheath 3 is covered on the insulator 2. The sheath 3 is formed with a thickness of, for example, 0.6 to 1.0 mm using, for example, flame-retardant polyethylene.

  In the power supply cable of this embodiment, from the viewpoint of heat resistance and heat-resistant life characteristics, the insulator 2 preferably has an oxidation induction period at 240 ° C. of 5 minutes or more, and more preferably 10 minutes or more. . The oxidation induction period refers to the time until the sample is oxidized and an exothermic peak occurs when air is introduced into the sample chamber of the differential scanning calorimeter set at a predetermined temperature (here, 240 ° C.).

  In the power supply cable of the present embodiment, the insulator 2 uses the polyolefin as described above as a base polymer, and a hindered phenol-based antioxidant, a sulfur-based antioxidant, and a hindered amine-based light stabilizer in a specific ratio. Since the insulating resin composition contained in is cross-linked by electron beam irradiation, the cross-linking effect by the electron beam and the antioxidant effect of the antioxidant are sufficiently exerted for power supply of the photovoltaic power generation system. It can be provided with heat resistance and heat life characteristics that sufficiently satisfy the characteristics required for the cable.

  The present invention is not limited to the embodiment described above, and it is needless to say that the present invention can be implemented in various forms without departing from the gist of the present invention.

  Next, examples of the present invention will be described, but the present invention is not limited to the following examples.

Example 1
100 parts by mass of polyethylene compound based on linear low density polyethylene (LLDPE, density 0.920 g / cm ³ ) (trade name DFDJ-7540 manufactured by Nippon Unicar Co., Ltd.), hindered phenol antioxidant (manufactured by BASF) Product name IRGANOX 1010) 0.50 parts by mass, sulfur-based antioxidant (trade name ADEKA STAB AO-412S manufactured by ADEKA Corporation) 0.40 parts by mass and hindered amine light stabilizer (trade name TINUVIN XT 855 FF manufactured by BASF); An insulating resin composition was obtained by uniformly kneading 0.10 parts by mass of a hindered amine light stabilizer (A) with a mixing roll.

Next, the insulating resin composition is extrusion coated to a thickness of 1.2 mm on a conductor composed of tin-plated annealed copper stranded wire (56 wires / 0.30 mm) having a cross-sectional area of 4 mm ² and irradiated with an electron beam (dose 250 kGy). After forming the insulator, a general-purpose flame-retardant polyethylene (trade name: CA1155B, manufactured by Nippon Polyethylene Co., Ltd.) is extrusion-coated to a thickness of 0.8 mm, and the outer diameter is about 6.7 mm. A power supply cable was manufactured.

(Examples 2 to 16, Comparative Examples 1 to 20)
An insulating resin composition was obtained in the same manner as in Example 1 except that the composition and / or the blending amount were changed as shown in Tables 1 and 2, and the Examples were further obtained using the obtained insulating resin composition. In the same manner as in Example 1, a power supply cable was manufactured.

Components other than the components used in Example 1 are as follows.
Ethylene / ethyl acrylate copolymer (EEA):
Product name manufactured by Nippon Polyethylene Co., Ltd. Lexpearl EEA A1150
Phosphorous antioxidants:
Product name Irgafos168 from BASF
Hindered amine light stabilizer (B):
BASF brand name Chimassorb2020

  The characteristics of the power feeding cables obtained in each of the above Examples and Comparative Examples were evaluated by the following method.

[Gel fraction]
The insulator sample peeled off from the power supply cable was measured according to JIS C 3005.
[Oxidation induction period]
About the insulator sample peeled off from the cable for electric power feeding, it measured at the temperature of 240 degreeC using the differential scanning calorimeter.
[Heat-resistant]
A heat aging test was carried out under three temperature conditions, the time required for an elongation remaining rate of 50% was determined, and the time required for the remaining rate of 50% at 120 ° C. to be calculated from the Arrhenius plot.
[Bloom]
The power supply cable was left at a temperature of 30 ° C. and a humidity of 80% RH. After 24 hours, the surface of the insulator was observed using a microscope to check for the presence of bloom.
○: No bloom ×: Bloom

  These results are shown in the lower column of Tables 1 and 2.

  As is clear from Tables 1 and 2, Examples 1, 2, 4, 6, 8, 9, 10, 12, 14 and 16 all gave good results in heat resistance, oxidation induction period, and bloom. It was. In Examples 3, 5, 7, 11, 13, and 15, results were obtained in which the oxidation induction period, bloom were good, and heat resistance was extremely good.

  DESCRIPTION OF SYMBOLS 1 ... Conductor, 2 ... Insulator, 3 ... Sheath.

Claims (5)

A power supply cable comprising an insulator and a sheath in order on the outer periphery of the conductor,
The insulator comprises a linear low density polyethylene and / or an ethylene / ethyl acrylate copolymer as a base polymer, and a hindered phenol antioxidant of 0.30 to 0.70% by mass, a sulfur antioxidant. An insulating resin composition containing 0.10 to 0.50% by mass and hindered amine light stabilizer 0.05 to 0.35% by mass is coated on the outer periphery of the conductor and crosslinked by electron beam irradiation. Power supply cable characterized by   The insulating resin composition has a hindered phenolic antioxidant of 0.55 to 0.65% by mass, a sulfuric antioxidant of 0.25 to 0.45% by mass, and a hindered amine light stabilizer of 0.05 to 0.05%. The power supply cable according to claim 1, comprising 0.25% by mass.   The hindered phenol-based antioxidant includes pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], and the sulfur-based antioxidant is pentaerythritol tetrakis (β The power supply cable according to claim 1, comprising: (lauryl-thiopropionate). The power supply cable according to any one of claims 1 to 3 , wherein the insulator has an oxidation induction period at 240 ° C of 5 minutes or more. The power supply cable according to any one of claims 1 to 4 , wherein the power supply cable is a solar power generation system power supply cable.

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