JP2021086751A - Cable and electric wire - Google Patents

Abstract

To provide a cable which has flame retardancy, heat resistance and restorability at a high level in a balanced manner.SOLUTION: The cable is provided, comprising a conductor, an insulating layer coating the periphery of the conductor, and an outer cover layer coating the periphery of the insulating layer. The outer cover layer is formed of a flame-retardant resin composition including a base polymer (A), a plasticizer (B), a stabilizer (C) and a flame retardant (D). The base polymer (A) includes a polyvinyl chloride resin (a1) and at least one urethane thermoplastic elastomer (a2) of an adipate-based urethane thermoplastic elastomer, a lactone-based urethane thermoplastic elastomer and a carbonate-based urethane thermoplastic elastomer in such a manner that a content of the urethane thermoplastic elastomer (a2) is 25 pts.mass or more and 640 pts.mass or less with respect to 100 pts.mass of the polyvinyl chloride resin (a1), the stabilizer (C) includes hydrotalcite (c1) and metal soap (c2), and the flame retardant (D) includes at least one of a metal hydroxide (d1), a bromine-based flame retardant (d2), amorphous silica (d3) and antimony trioxide (d4).SELECTED DRAWING: Figure 1

Description

The present invention relates to cables and electric wires.

The cable is configured by, for example, providing an outer skin layer (so-called sheath) as a covering material around an electric wire having an insulating layer provided around a conductor. The exodermis layer is formed of a resin composition containing rubber or a resin as a main raw material, and as this resin composition, for example, a soft vinyl chloride resin composition (soft PVC) containing a flame retardant is used.

The resin composition is required to have different properties depending on the use of the cable. For example, cables for FA robots are required to have flame retardancy, heat resistance, and resilience. In particular, in recent years, FA robots are composed of articulated and multi-axis types, and the cables used are repeatedly bent as the equipment moves, so that high resilience is required. Restorability means that the cable returns to its original shape when the cable is bent.

However, when soft PVC is used for the exodermis layer, the resilience of the exodermis layer is low, so that the cable may be broken when the FA robot is in operation. Therefore, in cables that require resilience, it has been proposed to use a resin composition in which an ether-based urethane thermoplastic elastomer (hereinafter, also simply referred to as TPU) is blended with soft PVC (see, for example, Patent Document 1). ) According to TPU, the exodermis layer can be imparted with resilience.

Japanese Unexamined Patent Publication No. 2016-91975

However, even if TPU is added to the exodermis layer, flame retardancy, heat resistance, and resilience may not be obtained in a well-balanced manner at a high level. Specifically, in the exodermis layer, a large amount of flame retardant may be added in order to obtain high flame retardancy, and this large amount of flame retardant causes the hard segment of TPU to collapse, and the heat resistance inherent in TPU. Will be damaged. On the other hand, if the amount of the flame retardant added is reduced in order to obtain heat resistance due to TPU, the desired flame retardancy may not be obtained. As described above, when TPU is used, although high resilience can be obtained, it may not be possible to maintain both flame retardancy and heat resistance at a high level.

An object of the present invention is to provide a technique for obtaining a high level of flame retardancy, heat resistance and resilience in a cable in a well-balanced manner.

According to one aspect of the invention
A cable including a conductor, an insulating layer coated around the conductor, and an outer skin layer coated around the insulating layer.
The exodermis layer is formed of a flame retardant resin composition containing a base polymer (A), a plasticizer (B), a stabilizer (C) and a flame retardant (D).
The base polymer (A) contains a polyvinyl chloride resin (a1) and at least one urethane thermoplastic elastomer (a2) of adipate-based, lactone-based and carbonate-based, and the content of the urethane thermoplastic elastomer (a2). It is contained so as to be 25 parts by mass or more and 640 parts by mass or less with respect to 100 parts by mass of the polyvinyl chloride resin (a1).
The stabilizer (C) contains hydrotalcite (c1) and metal soap (c2).
The flame retardant (D) contains at least one of a metal hydroxide (d1), a bromine-based flame retardant (d2), amorphous silica (d3) and antimony trioxide (d4).
Cables are provided.

According to another aspect of the invention
An electric wire provided with a conductor and an insulating layer coated around the conductor.
The insulating layer is formed of a flame retardant resin composition containing a base polymer (A), a plasticizer (B), a stabilizer (C) and a flame retardant (D).
The base polymer (A) contains a polyvinyl chloride resin (a1) and at least one urethane thermoplastic elastomer (a2) of adipate-based, lactone-based and carbonate-based, and the content of the urethane thermoplastic elastomer (a2). It is contained so as to be 25 parts by mass or more and 640 parts by mass or less with respect to 100 parts by mass of the polyvinyl chloride resin (a1).
The stabilizer (C) contains hydrotalcite (c1) and metal soap (c2).
The flame retardant (D) contains at least one of a metal hydroxide (d1), a bromine-based flame retardant (d2), amorphous silica (d3) and antimony trioxide (d4).
Wires are provided.

According to the present invention, flame retardancy, heat resistance and resilience can be obtained in a high level in a well-balanced manner in a cable.

It is sectional drawing which is perpendicular to the length direction of the cable which concerns on one Embodiment of this invention.

<Knowledge of the present inventors>
As described above, when TPU is mixed with soft PVC, the heat resistance is lowered due to a large amount of additives such as flame retardants entering the TPU. From this, the present inventors have investigated a combination of materials that selectively disperses the additive in PVC instead of TPU. Specifically, the types of plasticizers, stabilizers and flame retardants as materials were examined.

As a result, as a stabilizer, hydrotalcite and metal soap are preferable because they are easily dispersed in PVC, and as a flame retardant, they are easily dispersed in PVC. Therefore, metal hydroxide and bromine are used. It has been found that at least one of the flame retardants, amorphous silica and antimony trioxide should be used.

On the other hand, when TPU was also examined in order to increase the heat resistance of the mixture, it was found that among the TPUs, adipate-based, lactone-based and carbonate-based TPUs were preferable. Generally, the TPU is obtained by the reaction of a polyol, a diol and an isocyanate, and has a hard rigid hard segment and a flexible soft segment. Examples of the TPU include a polyester-based TPU using a polyester polyol and a polyether-based TPU using a polyether polyol. According to the studies by the present inventors, polyester-based TPU is desirable from the viewpoint of heat resistance. Further, although the polyester-based TPU varies depending on the type of polyester polyol, it has been found that adipate-based, lactone-based and carbonate-based are desirable from the viewpoint of various properties.

According to such a combination of materials, additives such as stabilizers and flame retardants can be selectively dispersed in PVC, so that a large amount of additives can be blended while taking advantage of the characteristics of PVC and TPU. As a result, the decrease in heat resistance can be suppressed. As a result, flame retardancy, heat resistance and resilience can be obtained at a high level in a well-balanced manner.

The present invention has been made based on the above findings.

<One Embodiment of the present invention>
Hereinafter, the cable according to the embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view perpendicular to the length direction of the cable according to the embodiment of the present invention. The numerical range represented by using "~" in the present specification means a range including the numerical values before and after "~" as the lower limit value and the upper limit value.

(Flame-retardant resin composition)
First, a flame-retardant resin composition that forms the outer skin layer of the cable will be described.

The flame retardant resin composition of the present embodiment contains a base polymer (A), a plasticizer (B), a stabilizer (C), a flame retardant (D), and, if necessary, other additives. Specifically, the base polymer (A) contains a polyvinyl chloride resin (a1) and at least one adipate-based, lactone-based and carbonate-based urethane thermoplastic elastomer (a2). Stabilizer (C) includes hydrotalcite (c1) and metal soap (c2). The flame retardant (D) contains at least one of a metal hydroxide (d1), a bromine-based flame retardant (d2), amorphous silica (d3) and antimony trioxide (d4).

Hereinafter, each component contained in the flame-retardant resin composition will be described in detail.

(Base polymer (A))
In the present embodiment, the polyvinyl chloride resin (a1) and at least one adipate-based, lactone-based, and carbonate-based urethane thermoplastic elastomer (a2) are used as the base polymer (A).

As the polyvinyl chloride resin (a1), a homopolymer of vinyl chloride, a copolymer of vinyl chloride and another copolymerizable monomer, or the like can be used. As such a copolymer, for example, a copolymer of vinyl chloride and ethylene, vinyl acetate or the like can be used. Further, as the polyvinyl chloride resin (a1), a partially crosslinked resin may be used.

The average degree of polymerization of the polyvinyl chloride resin (a1) is not particularly limited, but is preferably 1000 to 3800, and more preferably 1300 to 2500. By setting the average degree of polymerization to 1000 or more, high heat resistance can be obtained in the exodermis layer. On the other hand, if the average degree of polymerization is excessively high, the molding processability of the flame-retardant resin composition may be lowered. However, by setting the average degree of polymerization to 3800 or less, the outer skin layer is not impaired in the molding processability. Heat resistance can be increased. A plurality of polyvinyl chloride resins (a1) having different average degrees of polymerization may be used in combination.

Urethane thermoplastic elastomer (a2) is a component that mainly imparts resilience to the exodermis layer. The urethane thermoplastic elastomer (a2) of the present embodiment is an adipate-based, lactone-based or carbonate-based. The adipate type is a TPU obtained by reacting with an adipic acid type polyester polyol, a diol, and an isocyanate. The lactone type is, for example, a TPU obtained by reacting a caprolactone-based polyester polyol with a diol or an isocyanate. The carbonate type is, for example, a TPU obtained by reacting a carbonate compound type polyester polyol with a diol or an isocyanate.

Examples of the diol include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,3-butanediol, 1,6-hexanediol, and 1,8-octanediol. , 1,9-Nonandiol, Neopentyl glycol, 2-Butyl-2-ethyl-1,3-Propanediol, 3-Methyl-1,5-Pentanediol, 2-Methyl-1,3-Propanediol, 3 , 3,5-trimethylpentanediol, 2,4-diethyl-1,5-pentanediol, 1,12-octadecanediol, 1,2-alkanediol, 1,3-alkanediol, 1-monoglyceride, 2-monoglyceride , 1-monoglycerin ether, 2-monoglycerin ether, dimerdiol, hydrogenated dimerdiol and the like.

Known components can be used as the isocyanate. For example, fats such as hexamethylene diisocyanate, butane-1,4-diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, xylylene diisocyanate, and m-tetramethylxylylene diisocyanate. Group diisocyanate can be mentioned. In addition, isophorone diisocyanate, cyclohexane-1,4-diisocyanate, lysine diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, 1,3-bis (isocyanatemethyl) cyclohexane, methylcyclohexanediisocyanate, 4,4'-dicyclohexylmethane diisocyanate, Examples thereof include alicyclic diisocyanates such as isopropyridene dicyclohexyl-4,4'-diisocyanate and norbornane diisocyanate. Further, 1,5-naphthylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-diphenyldimethylmethane diisocyanate, 4,4'-dibenzyl diisocyanate, dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, 1,3- Examples thereof include aromatic diisocyanates such as phenylenediisocyanate, 1,4-phenylenediocyanate, tolylene diisocyanate, and tetramethylxylylene diisocyanate.

The TPU (a2) is not particularly limited as long as it is an adipate-based, lactone-based or carbonate-based TPU (a2) from the viewpoint of heat resistance of the exodermis layer, but an adipate-based TPU is preferable from the viewpoint of adjusting the hardness of the exodermis layer. The adipate type not only adjusts the hardness, but also has an excellent affinity with the polyvinyl chloride resin (a1) as compared with the lactone type and the carbonate type, and has a phase structure described later in the flame-retardant resin composition constituting the exodermis layer. It is easy to form, and various characteristics can be realized more stably and at a high level.

The hardness of the adipate-based TPU (a2) is not particularly limited, but from the viewpoint of the balance between the resilience of the exodermis layer and the heat resistance, the shore A hardness is preferably 80A to 95A, preferably 80A to 90A. Is more preferable.

The base polymer (A) may contain a polymer component other than the above components (a1) and (a2) as appropriate as long as the characteristics of the exodermis layer are not impaired. For example, as shown in Examples described later, an ether-based TPU may be used in combination. The amount of the other polymer component added may be 5% or less of the polyvinyl chloride resin (a1).

(Plasticizer (B))
The plasticizer (B) is a component that imparts flexibility to the exodermis layer. As the plasticizer (B), known components such as trimellitic acid ester, phthalate ester, and adipic acid polyester can be used. Of these, the trimellitic acid ester is preferable because it does not impair various properties of the exodermis layer. Trimellitic acid esters can maintain higher heat resistance of the exodermis layer than phthalates. Further, since the outer skin layer is not sticky as compared with polyester adipic acid, the handleability of the cable can be improved. The trimellitic acid ester may be used alone, or may be used in combination with, for example, polyester adipic acid as long as the characteristics of the exodermis layer are not impaired.

As the trimellitic acid ester, for example, tri2ethylhexyl trimellitic acid, trinoctyl trimellitic acid, trimixed alkyl trimellitic acid, triisononyl trimellitic acid and the like can be used.

(Stabilizer (C))
The stabilizer (C) acts as a heat stabilizer that suppresses deterioration of the polyvinyl chloride resin (a1) when preparing the flame-retardant resin composition, and stabilizes the phase structure of the flame-retardant resin composition. It is an ingredient. In this embodiment, hydrotalcite (c1) and metal soap (c2) are used from the viewpoint of selectively dispersing them in the polyvinyl chloride resin (a1). The hydrotalcite (c1) and the metal soap (c2) are not particularly limited as long as they have excellent compatibility with the polyvinyl chloride resin (a1), and known components can be used. As the metal soap (c2), for example, a component composed of fatty acids such as stearic acid, lauric acid and octyl acid and metals such as calcium and zinc can be used.

The stabilizer (C) may contain a stabilizing aid as a component other than the above. The stabilizing aid is a component that has no effect on the TPU (a2) with or without addition and acts only on the polyvinyl chloride resin (a1). As the stabilizing aid, for example, dibensoil methane, stearylbenzoyl methane and metal salts thereof, polyhydric alcohols, trihydroxyethyl isocyanate, silica, calcium carbonate, antioxidant, talc, clay and the like are used as required. Can be used in an appropriate amount.

(Flame retardant (D))
The flame retardant (D) is a component that imparts flame retardancy to the exodermis layer. In the present embodiment, from the viewpoint of selectively dispersing the additive in the polyvinyl chloride resin (a1), the flame retardant (D) includes a metal hydroxide (d1), a bromine-based flame retardant (d2), and an amorphous substance. At least one of silica (d3) and antimony trioxide (d4) is used.

As the metal hydroxide (d1), for example, magnesium hydroxide, aluminum hydroxide and the like can be used. Of these, aluminum hydroxide is particularly preferable. In magnesium hydroxide, as the alkalinity of the flame-retardant resin composition increases, the urethane bonding force, hydrogen bonding force, ester bonding force, etc. in the hard segment of TPU weaken, and the heat resistance of TPU may be impaired. There is. In this respect, according to aluminum hydroxide, high heat resistance can be maintained without increasing the alkalinity excessively. The metal hydroxide (d1) may not be surface-treated, or may be surface-treated such as silane treatment. From the viewpoint of dispersibility, the metal hydroxide (d1) preferably has an average particle size of 5 μm or less. The lower limit is not particularly limited, but is, for example, 0.8 μm.

As the brominated flame retardant (d2), for example, decabromodiphenyl ether, decabromodiphenyl ethane and the like can be used. From the viewpoint of dispersibility, the brominated flame retardant (d2) preferably has an average particle size of 10 μm or less. The lower limit is not particularly limited, but is, for example, 2 μm.

The amorphous silica (d3) preferably has an average particle size of 5 μm or less from the viewpoint of dispersibility. The lower limit is not particularly limited, but is, for example, 0.01 μm.

The antimony trioxide (d4) preferably has an average particle size of 5 μm or less from the viewpoint of dispersibility. The lower limit is not particularly limited, but is, for example, 0.5 μm.

(Other additives)
In addition to the components (A) to (D), other additives may be added to the flame-retardant resin composition, if necessary. As other additives, for example, a cross-linking aid, an antioxidant (anti-aging agent), a copper damage inhibitor, a lubricant or a processing aid can be used.

Specifically, the cross-linking aid includes trimethylolpropane trimethacrylate (TMPT), triallyl isocyanurate, triallyl cyanurate, N, N'-metaphenylene bismaleimide, ethylene glycol dimethacrylate, zinc acrylate or methacrylic acid. Examples include zinc acid.

Further, examples of the antioxidant include a phenol-based antioxidant, a phosphorus-based antioxidant, a sulfur-based antioxidant, and the like. Examples of the copper damage inhibitor include N- (2H-1,2,4-triazole-5-yl) salicylamide and bis dodecanoate [N2- (2-hydroxybenzoyl) hydrazide], 2', 3-bis. [[3- [3,5-di-tert-butyl-4-hydroxyphenyl] propionyl]] propionohydrazide and the like can be mentioned, and more preferably 2', 3-bis [[3- [3,5-] Di-tert-butyl-4-hydroxyphenyl] propionyl]] propionohydrazide.

Examples of the lubricant include hydrocarbon-based, fatty acid-based, fatty acid amide-based, ester-based, and alcohol-based lubricants.

Examples of the processing aid include ricinoleic acid, stearic acid, palmitic acid, lauric acid, salts or esters thereof, polymethylmethacrylate and the like.

(Phase structure)
In the flame-retardant resin composition of the present embodiment, the polyvinyl chloride resin (a1) and TPU (a2) form a sea-island structure by dispersing one component in the other component, or spinodal-dispersed. There is. Since the stabilizer (C) and the flame retardant (D) are more easily dispersed in the polyvinyl chloride resin (a1) than the TPU (a2), less additives enter the TPU (a2). It is possible to suppress a decrease in the urethane bonding force and the hydrogen bonding force of the component (a2), and it is possible to maintain the original characteristics of the component (a2).

(Content ratio)
The content ratio of each component in the resin composition is as follows.

In the flame-retardant resin composition, the content of the urethane thermoplastic elastomer (a2) is X, the total content of the polyvinyl chloride resin (a1), the plasticizer (B), the stabilizer (C) and the flame retardant (D). When is Y, the ratio X / Y is preferably 5/95 to 70/30. By blending each component in such a ratio, the additive can be selectively dispersed in the component (a1), and various properties can be further improved in the exodermis layer.

In the base polymer (A), the ratio of the polyvinyl chloride resin (a1) and the TPU (a2) is TPU (a2) with respect to 100 parts by mass of the polyvinyl chloride resin (a1) from the viewpoint of obtaining various characteristics in a well-balanced manner. ) Is 25 parts by mass to 640 parts by mass, preferably 47 parts by mass to 510 parts by mass, and more preferably 115 parts by mass to 336 parts by mass.

The content of the plasticizer (B) is not particularly limited, but if it is excessively small, the resilience becomes low and various properties can be obtained in a well-balanced manner when the polyvinyl chloride resin (a1) and the TPU (a2) are mixed. Not only that, there is a risk that moldability and cold resistance will decrease. Further, if the amount is excessively large, the adhesiveness of the exodermis layer may increase and the moldability and flame retardancy may decrease. From the viewpoint of obtaining various properties in the exodermis layer at a high level and in a well-balanced manner, the content of the plasticizer (B) is 30 parts by mass to 95 parts by mass with respect to 100 parts by mass of the polyvinyl chloride resin (a1). preferable.

The content of the stabilizer (C) is not particularly limited, but the metal soap (c2) is more likely to reduce the hydrogen bonding force and the urethane bonding force in the hard segment of the TPU (a2) than the hydrotalcite (c1), and is exodermis. The heat resistance of the skin layer may be impaired. Therefore, from the viewpoint of stabilizing the polyvinyl chloride resin (a1) and maintaining high heat resistance, in order to reduce the content of the metal soap (c2) and ensure the effect of the stabilizer (C). It is advisable to increase the content of hydrotalcite (c1). Specifically, the content of the metal soap (c2) is 1.6 parts by mass or less with respect to 100 parts by mass of the polyvinyl chloride resin (a1), and the content of the hydrotalcite (c1) is the metal soap (c2). It is preferable that the content is 4 times or more the content of. The lower limit of the content of the metal soap (c2) is not particularly limited, but if it is excessively small, the flame-retardant resin composition will be colored or its characteristics will be deteriorated. It is preferable to do so. The content of hydrotalcite (c1) is not particularly limited, but is preferably 3.2 parts by mass to 16 parts by mass with respect to 100 parts by mass of PVC (a1). The total content of the stabilizer (C) is preferably 4 parts by mass to 20 parts by mass.

The content of the flame retardant (D) is not particularly limited, but the total content of (d1) to (d4) may be 5 parts by mass to 80 parts by mass with respect to 100 parts by mass of the base polymer (A). It is preferably 5 parts by mass to 70 parts by mass, more preferably 5 parts by mass to 40 parts by mass. The contents of (d1) to (d4) are not particularly limited as long as the total amount is within the above range, but are preferably set to the following ranges. (D1) is 0 parts by mass to 50 parts by mass, (d2) is 0 parts by mass to 50 parts by mass, (d3) is 0 parts by mass to 40 parts by mass, and (d4) is 0 parts by mass to 50 parts by mass.

(Preparation of flame-retardant resin composition)
The flame-retardant resin composition may be prepared by mixing (A) to (D) above and, if necessary, other additives and melt-kneading. The kneading may be carried out using a known kneading device such as a batch type kneader such as a Banbury mixer or a pressure kneader, or a continuous kneader such as a twin-screw extruder.

Specifically, first, a polyvinyl chloride resin (a1), a plasticizer (B), a stabilizer (C) and a flame retardant (D) are kneaded to obtain pellets of a soft PVC mixture. Subsequently, the obtained pellet of the soft PVC mixture and TPU (a2) are mixed and melt-kneaded. Thereby, the TPU (a2) can be dispersed in the soft PVC, or the soft PVC can be dispersed in the TPU (a2) to form a flame-retardant resin composition. In the flame-retardant resin composition, by preparing a soft PVC mixture in advance, it is possible to reduce the entry of additives into the phase of TPU (a2). This makes it possible to maintain higher heat resistance in the exodermis layer. The soft PVC mixture may be in a powder state in which a polyvinyl chloride resin (a1), a plasticizer (B), a stabilizer (C) and a flame retardant (D) are mixed.

Even when the materials are mixed and melt-kneaded, the polyvinyl chloride resin (a1) melts at a temperature lower than that of the TPU (a2), so that various additives are more (a1) than the component (a2). ), But by preparing the soft PVC in advance as described above, it is possible to further reduce the entry of the additive into the component (a2).

(cable)
Subsequently, the cable of the present embodiment will be described with reference to FIG. FIG. 1 is a cross-sectional view perpendicular to the length direction of the cable according to the embodiment of the present invention.

As shown in FIG. 1, the cable 1 of the present embodiment is formed around the electric wire 10 in which the insulating layer 12 is formed around the conductor 11, the shield layer 13 provided around the electric wire 10, and the shield layer 13. The outer skin layer 14 (sheath 14) to be formed is provided.

(conductor)
As the conductor 11, in addition to commonly used metal wires such as copper wire and copper alloy wire, aluminum wire, gold wire, silver wire and the like can be used. Further, as the conductor 11, a conductor having metal plating such as tin or nickel around the metal wire may be used. Further, as the conductor 11, a stranded wire obtained by twisting metal wires can also be used.

(Insulation layer)
The insulating layer 12 is provided around the conductor 11. The insulating layer 12 may be formed of a conventionally known material, for example, a fluororesin, a polyester resin, high-density polyethylene, or an admixture to which a flame retardant, an antioxidant, or the like is added, in order to form the above-mentioned outer skin layer. It may be formed of the flame retardant resin composition of. The thickness of the insulating layer 12 is not particularly limited, and may be, for example, 0.1 mm to 1.5 mm.

(Shield layer)
The shield layer 13 is provided around a stranded wire obtained by twisting a plurality of electric wires 10. The shield layer 13 is formed by a braided structure in which a plurality of metal strands such as annealed copper wires are woven.

(Exodermis layer)
The exodermis layer 14 is provided around the shield layer 13 and is formed from the flame-retardant resin composition described above. The thickness of the outer skin layer 14 is not particularly limited, but is preferably 0.1 mm to 2 mm from the viewpoint of obtaining various characteristics in a well-balanced manner at a high level.

From the viewpoint of enhancing the oil resistance of the exodermis layer 14 and the flame-retardant stability during combustion, the flame-retardant resin composition may be crosslinked. The cross-linking method is not particularly limited, and for example, electron beam cross-linking can be adopted. When performing electron beam cross-linking, it is preferable to irradiate the extruded flame-retardant resin composition with an electron beam of 1 to 30 mad to cross-link.

(Cable manufacturing method)
First, the conductor 11 is prepared, and for example, the above-mentioned flame-retardant resin composition is extruded by an extrusion molding machine so as to cover the periphery of the conductor 11 to form an insulating layer 12 having a predetermined thickness to obtain an electric wire 10. .. Subsequently, a plurality of electric wires 10 are twisted together, and a shield layer 13 is formed around the electric wires 10 by a braiding machine. Subsequently, the flame-retardant resin composition is extruded by an extrusion molding machine so as to cover the periphery of the shield layer 13 to form an outer skin layer 14 having a predetermined thickness. As a result, the cable 1 of the present embodiment can be manufactured.

<Effect of this embodiment>
According to this embodiment, one or more of the following effects are exhibited.

According to the cable 1 of the present embodiment, the flame retardant resin composition forming the outer skin layer 14 is at least one of a polyvinyl chloride resin (a1) as a base polymer (A) and an adipate-based, lactone-based and carbonate-based resin. It contains one urethane thermoplastic elastomer (a2) in a predetermined ratio, hydrotalcite (c1) and metal soap (c2) as a plasticizer (B) and a stabilizer (C), and a metal as a flame retardant (D). It contains at least one of a hydroxide (d1), a brominated flame retardant (d2), an amorphous silica (d3) and an antimony trioxide (d4). Since the component (C) and the component (D) are more easily dispersed in the polyvinyl chloride resin (a1) than the TPU (a2), it is possible to reduce the entry of additives into the TPU (a2). Therefore, in the component (a2), it is possible to suppress a decrease in urethane bonding force and hydrogen bonding force due to the entry of additives. As a result, the heat resistance of the exodermis layer 14 can be maintained high while obtaining the resilience of the component (a2). Further, since at least one (a2) component of adipate-based, lactone-based and carbonate-based is used as the TPU, the heat resistance of the exodermis layer 14 can be maintained higher. Further, according to the combination of the plasticizer (B) and the stabilizer (C), the characteristics inherent in the components (a1) and (a2) can be maintained high without being significantly impaired. Further, according to the flame retardant (D), the flame retardancy of the exodermis layer 14 can be improved. Therefore, according to the cable 1 of the present embodiment, stability, heat resistance, and flame retardancy can be obtained in a well-balanced manner at a high level.

Specifically, the cable 1 of the present embodiment has high flame retardancy so as to pass the vertical flame retardant test VW-1 defined in the flame retardancy standard UL1581. In addition, it has high heat resistance that satisfies the 105 ° C rating in the UL standard. Furthermore, it has high resilience so that it will not break when used as a cable for FA robots.

The TPU (a2) is preferably an adipate type. According to the adipate-based TPU, the hardness of the exodermis layer can be appropriately adjusted as compared with the lactone-based and carbonate-based TPUs.

Further, the content of hydrotalcite (c1) is set to 4 times or more the content of the metal soap (c2), and the content of the metal soap (c2) is 1. It is preferably 6 parts by mass or less. As a result, it is possible to suppress a decrease in the hydrogen bonding force and the urethane bonding force of the TPU (a2), and it is possible to maintain high heat resistance of the outer skin layer 14.

The plasticizer (B) is preferably a trimellitic acid ester. According to the trimellitic acid ester, the heat resistance of the exodermis layer can be maintained high.

The content of the plasticizer (B) is preferably 30 parts by mass to 95 parts by mass with respect to 100 parts by mass of the polyvinyl chloride resin (a1). With such a content, heat resistance, flame retardancy and resilience can be maintained higher in the exodermis layer.

The content of the flame retardant (D) is preferably 5 parts by mass to 80 parts by mass with respect to 100 parts by mass of the polyvinyl chloride resin (a1). With such a content, heat resistance, flame retardancy and resilience can be maintained higher in the exodermis layer.

Further, according to the cable 1 of the present embodiment, since TPU (a2) is blended in the outer skin layer 14, oil resistance and cold resistance can be improved as compared with the case where only PVC is blended.

In the flame-retardant resin composition, the content X of the urethane thermoplastic elastomer (a2) and the total content of the polyvinyl chloride resin (a1), the plasticizer (B), the stabilizer (C) and the flame retardant (D). The ratio X / Y to Y is preferably 5/95 to 70/30. By blending each component in such a ratio, the additive can be selectively dispersed in the component (a1), and various properties can be further improved in the exodermis layer 14.

Further, in the present embodiment, since the polymer alloy is formed by using the two components (a1) and (a2) in combination as the base polymer (A), desired unevenness is imparted to the surface of the exodermis layer 14. Can be done. Thereby, the surface frictional resistance of the cable 1 can be reduced.

In the present embodiment, the case where the above-mentioned flame-retardant resin composition is used for the outer skin layer of the cable has been described, but the present invention is not limited to this. For example, the flame-retardant resin composition can also be used for an insulating layer of an electric wire. The flame-retardant resin composition may be used as it is, but for example, 5 parts by mass to 60 parts by mass, preferably 30 parts by mass to 50 parts by mass is added to 100 parts by mass of the polyvinyl chloride resin (a1). It is good to use it.

Next, the present invention will be described in more detail based on Examples, but the present invention is not limited to these Examples.

<Material>
In this example, the materials used for the flame-retardant resin composition for the exodermis layer are as follows.

The following was used as the polyvinyl chloride resin (a1).
-Polyvinyl chloride resin 1 (product name "TH-1300", manufactured by Taiyo PVC Co., Ltd., average degree of polymerization 1270-1370)
-Polyvinyl chloride resin 2 (product name "TH-1700", manufactured by Taiyo PVC Co., Ltd., average degree of polymerization 1600-1800)
-Polyvinyl chloride resin 3 (product name "TH-2500", manufactured by Taiyo PVC Co., Ltd., average degree of polymerization 2400-2600)

The following was used as the urethane thermoplastic elastomer (a2).
・ Adipate type TPU1 (Product name "P25MRWJE", manufactured by Nippon Miractran Co., Ltd., Shore A hardness 90)
・ Adipate type TPU2 (Product name "P485RWJE", manufactured by Nippon Miractran Co., Ltd., Shore A hardness 85)

The following ether types were used as the ether-based urethane thermoplastic elastomer (a2)'for comparison.
-Ether type TPU1 (Product name "ET890 black", manufactured by BASF Corporation, Shore A hardness 90)

The following was used as the plasticizer (B).
-Di2ethylhexyl trimellitic acid (TOTM) (product name "T08", manufactured by Kao Corporation)
-Dioctyl trimellitic acid (n-TOTM) (product name "N08", manufactured by Kao Corporation)

The following was used as the hydrotalcite (c1) of the stabilizer (C).
・ Hydrotalcite (product name "HT-1", manufactured by Sakai Chemical Co., Ltd.)

The following was used as the metal soap (c2) of the stabilizer (C).
-Zinc stearate (product name "SZ-P", manufactured by Sakai Chemical Co., Ltd.)
・ Calcium stearate (product name "SC-P", manufactured by Sakai Chemical Co., Ltd.)

The following were used as other components of the stabilizer (C).
・ Stabilizing aid (including β-diketone, etc.)

The following was used as the metal hydroxide (d1) of the flame retardant (D).
-Untreated aluminum hydroxide (product name "BF013", manufactured by Nippon Light Metal Co., Ltd.)
-Silane-treated aluminum hydroxide (product name "BF013STV", manufactured by Nippon Light Metal Co., Ltd.)

The following was used as the brominated flame retardant (d2) of the flame retardant (D).
-Brominated flame retardant (decabromodiphenylethane, product name "Cytex 8010", manufactured by Albemarle Corporation, average particle size 5.6 μm)

The following was used as the amorphous silica (d3) of the flame retardant (D).
Amorphous silica (product name "SIDISTAR120U", manufactured by Elchem Co., Ltd., average particle size 0.15 μm)

The following was used as the antimony trioxide (d4) of the flame retardant (D).
・ Antimony trioxide (product name "NANO200", manufactured by Chenzhou Chenzhou, average particle size 0.8 μm)

The following were used as other additives.
・ Cross-linking aid (trimethylolpropane trimethacrylate, product name "TMPT", manufactured by Shin-Nakamura Chemical Co., Ltd.)
-Baked clay (product name "SP # 33", manufactured by BASF)
-Colorant black (product name "NBP2425", manufactured by Nikko Bics Co., Ltd.)
-Colorant white (product name "Titanium White R820", manufactured by Ishihara Sangyo Co., Ltd.)
-Antioxidant (product name "AO-26", manufactured by ADEKA CORPORATION)

<Example 1>
First, a conductor, a resin composition for forming an insulating layer, and a flame-retardant resin composition for forming an exodermis layer were prepared.

As the conductor, a 28 AWG (19 / 0.08) TA conductor was used.

As the resin composition for forming the insulating layer, a composition containing ETFE (tetrafluoroethylene / ethylene copolymer), which is a fluororesin, was used.

The flame-retardant resin composition for forming the exodermis layer was prepared by mixing and kneading the above-mentioned materials so as to have the compositions shown in Table 1 below. Specifically, the base polymer (A) is 100 parts by mass of the polyvinyl chloride resin 2, the adipate type TPU1 is 167.1 parts by mass, the plastic agent (B) is 60 parts by mass of TOTM, and the stabilizer (C). 11.66 parts by mass of hydrotalcite (c1), 1.14 parts by mass of zinc stearate, which is a metal soap (c2), 1.2 parts by mass of stabilizing aid, and metal as flame retardant (D). 5.0 parts by mass of untreated aluminum hydroxide as a hydroxide (d1), brominated flame retardant (d2), amorphous silica (d3) and antimony trioxide (d4), and other additives. As a result, 1.0 part by mass of the cross-linking aid, 5.2 parts by mass of the baked clay, 3.5 parts by mass of the colorant black, and 0.5 parts by mass of the colorant white are kneaded, for a total of 371.3 parts by mass. Then, the flame retardant resin composition of Example 1 was prepared. In Example 1, the ratio of the content X of the adipate-based TPU (a2) to the total content Y of the polyvinyl chloride resin (a1), the plasticizer (B), the stabilizer (C) and the flame retardant (D). It was prepared so that X / Y was 0.86. The flame-retardant resin composition was prepared by melt-kneading at a take-out temperature of 165 ° C., strand-cutting, and then drying at 80 ° C. for 2 hours using a pressure kneader.

Next, a resin composition for forming an insulating layer was extruded around the conductor using a 40 mm extruder for manufacturing an electric wire to form an insulating layer having a thickness of 0.2 mm. This gave an electric wire. After that, five electric wires were twisted together, and a rayon yarn and a polyester tape (1/4 wrap) were twisted (right-twisted) around the wire using a braiding machine to form a shield layer. Subsequently, a flame-retardant resin composition was extruded around the shield layer by a tube extrusion method using a 65 mm single-screw extruder for manufacturing electric wires to form an outer skin layer having a thickness of 1 mm. As a result, the cable of Example 1 was produced.

<Examples 2 and 3>
In Examples 2 and 3, a cable was produced in the same manner as in Example 1 except that the thickness of the exodermis layer was changed to 0.4 mm or 1.6 mm.

<Example 4>
In Example 4, every 50 parts by mass of polyvinyl chloride resin 1 and polyvinyl chloride resin 3 having different average degrees of polymerization were used in combination, and 50 parts by mass of n-TOTM was used as the cross-linking agent (B). A flame-retardant resin composition was prepared in the same manner as in Example 1, and a cable was prepared.

<Examples 5 to 7>
In Examples 5 to 7, the flame retardant resin composition was the same as in Example 1 except that the contents of the adipate type TPU1, the plasticizer (B) and the flame retardant (D) were appropriately changed as shown in Table 1. The thing was prepared and the cable was made.

<Examples 8 and 9>
In Examples 8 and 9, the contents of the stabilizer (C) hydrotalcite (c1), the metal soap (c2), and the stabilizing aid were appropriately changed as shown in Table 1, except that the contents of Examples were changed as appropriate. A flame-retardant resin composition was prepared in the same manner as in No. 1, and a cable was prepared.

<Example 10>
In Example 10, it is difficult as in Example 1 except that as the adipate-based TPU (a2), adipate type TPU2 having a shore A hardness of 85 is used instead of adipate type TPU1 having a shore A hardness of 90. A flammable resin composition was prepared and a cable was prepared.

<Example 11>
In Example 11, a flame-retardant resin composition was prepared in the same manner as in Example 1 except that a small amount of ether-based urethane thermoplastic elastomer (a2)'was used in combination with adipate-based TPU (a2) to prepare a cable. ..

<Examples 12 and 13>
In Examples 12 and 13, a flame-retardant resin composition was prepared in the same manner as in Example 1 except that 0.8 parts by mass and 0.4 parts by mass of antioxidants were added as other additives, respectively, and a cable was prepared. Was produced.

<Example 14>
In Example 14, a flame-retardant resin composition was prepared in the same manner as in Example 1 except that the flame-retardant resin composition was extruded and then crosslinked by irradiating an electron beam with an irradiation intensity of 3Mrad. Made.

<Comparative example 1>
In Comparative Example 1, as shown in Table 2 below, the same as in Example 1 except that an ether type urethane thermoplastic elastomer (a2') was used instead of the adipate type urethane thermoplastic elastomer (a2). A flame-retardant resin composition was prepared to prepare a cable.

<Comparative Examples 2 and 3>
In Comparative Examples 2 and 3, a flame-retardant resin composition was prepared in the same manner as in Example 1 except that the addition amounts of the ether type urethane thermoplastic elastomer (a2') and the plasticizer (B) were appropriately changed. A cable was made.

<Comparative example 4>
In Comparative Example 4, a flame-retardant resin composition was prepared in the same manner as in Example 1 except that the flame retardant (D) was not blended, and a cable was produced.

<Evaluation>
The heat resistance, flame retardancy and resilience of the prepared cables of Examples 1 to 14 and Comparative Examples 1 to 4 were evaluated. Each evaluation was performed as follows.

(Heat-resistant)
Heat resistance was evaluated by a test compliant with UL1581. Specifically, a sample (length of about 100 mm) containing only the exodermis layer of the produced cable was exposed to a gear oven at 136 ° C. for 168 hours to obtain initial tensile strength and elongation and post-exposure tensile strength and elongation. Was compared. Then, the tensile strength residual ratio (%) and the elongation residual ratio (%) are calculated by the following formulas, and those having a tensile strength residual ratio of 70% or more and an elongation residual ratio of 45% or more are regarded as "pass". Those that do not meet any of the above, or those that do not meet any of these, were regarded as "failed".
Residual tensile strength (%) = 100 x (tensile strength after the above exposure) / (initial tensile strength)
Residual growth rate (%) = 100 x (elongation after the above exposure) / (initial elongation)

(Flame retardance)
Flame retardancy was evaluated by testing according to UL1581. Specifically, the vertical flame retardancy test VW-1 specified in UL1581 was performed three times on the manufactured cable (length of about 500 mm), and those that met the criteria all three times were regarded as "passed". Those who did not meet the criteria even once were regarded as "failed".

(Stability)
Restorability was evaluated by the following method. First, a sample piece was obtained by punching the exodermis layer collected from each cable into a dumbbell shape. Subsequently, using a tensile tester, this sample piece was stretched 100% under the conditions of a distance between marked lines of 25 mm and a tensile speed of 200 mm / min, and then the testing machine was stopped. Then, the dumbbell was detached and marked 10 seconds later. The extent to which the line spacing of 25 mm was extended (X value) was measured. Then, the degree of restoration (Y) was calculated from the following formula. In this embodiment, a Y value of 60 or more was regarded as a pass, and a Y value of less than 60 was regarded as a failure. It has been confirmed that the stability Y is an index of stability because it shows a certain degree of correlation with the rebound resilience.
Y = -4 * X + 200

<Evaluation result>
The evaluation results of heat resistance, flame retardancy and resilience of cables are summarized in Tables 1 and 2.

According to Examples 1 to 3, it was confirmed that heat resistance, flame retardancy and resilience can be obtained at a high level in a well-balanced manner regardless of the thickness of the exodermis layer.

According to Example 4, it was confirmed that even if two types of polyvinyl chloride resins having different average degrees of polymerization were used, a balance of various properties could be realized in the exodermis layer.

According to Examples 5 to 7, the content X of the adipate-based TPU (a2) and the total content of the polyvinyl chloride resin (a1), the plasticizer (B), the stabilizer (C) and the flame retardant (D). It was confirmed that the balance of various characteristics can be obtained at a high level by adding each material so that the ratio X / Y with Y is 0.07 to 1.71.

According to Examples 1, 8 and 9, the content of hydrotalcite (c1) is four times or more that of the metal soap (c2), and the content of the metal soap (c2) is 100 mass by mass of the polyvinyl chloride resin (a2). It was confirmed that the balance of various characteristics can be obtained at a high level by setting the amount to 1.6 parts by mass or less with respect to the part.

According to Example 10, it was confirmed that even if the adipate-based TPU (a2) has a shore A hardness of 85, various characteristics can be obtained at a high level as in the case of the shore A hardness of 90.

According to Example 11, it was confirmed that the balance of various characteristics can be maintained at a high level even when a small amount of ether-based TPU is used in combination with adipate-based TPU (a2).

According to Examples 12 and 13, it was confirmed that the addition of an antioxidant has high heat resistance and can be stably obtained.

According to Example 14, it was confirmed that even if the exodermis layer was crosslinked, various characteristics could be obtained at a high level in a well-balanced manner. It was confirmed that the exodermis layer of Example 14 can be stably extinguished even if the exodermis layer is burned by the cross-linking treatment. It was also confirmed that not only the flame-retardant property but also the storage elastic modulus at 80 ° C. or higher can be improved.

On the other hand, in Comparative Example 1, since the ether-based TPU (a2)'was mixed with the polyvinyl chloride resin (a1), it was confirmed that the heat resistance was impaired by the addition of the flame retardant. On the other hand, in Comparative Example 2, it was confirmed that the desired flame retardancy could not be obtained. Further, in Comparative Example 3, it was confirmed that although the amount of the ether-based TPU (a2)'added was reduced, heat resistance and flame retardancy were obtained in a well-balanced manner, but desired stability could not be obtained. That is, in Comparative Examples 1 to 3, it was confirmed that heat resistance, flame retardancy and resilience could not be obtained at a high level in a well-balanced manner.

In Comparative Example 4, although the polyvinyl chloride resin (a1) and the adipate-based TPU (a2) were used in combination, it was confirmed that the desired flame retardancy could not be obtained because the flame retardant (D) was not blended. ..

As described above, according to the above-mentioned combination of the base polymer (A), the plasticizer (B), the plasticizer (C) and the flame retardant (D), the exodermis layer has heat resistance, flame retardancy and flame retardancy. Restorability can be obtained at a high level in a well-balanced manner. According to the cable provided with such an outer skin layer, it can be used as an FA robot cable.

<Preferable Aspect of the Present Invention>
Hereinafter, preferred embodiments of the present invention will be added.

[Appendix 1]
One aspect of the present invention is
A cable including a conductor, an insulating layer coated around the conductor, and an outer skin layer coated around the insulating layer.
The exodermis layer is formed of a flame retardant resin composition containing a base polymer (A), a plasticizer (B), a stabilizer (C) and a flame retardant (D).
The base polymer (A) contains a polyvinyl chloride resin (a1) and at least one urethane thermoplastic elastomer (a2) of adipate-based, lactone-based and carbonate-based, and the content of the urethane thermoplastic elastomer (a2). It is contained so as to be 25 parts by mass or more and 640 parts by mass or less with respect to 100 parts by mass of the polyvinyl chloride resin (a1).
The stabilizer (C) contains hydrotalcite (c1) and metal soap (c2).
The flame retardant (D) contains at least one of a metal hydroxide (d1), a bromine-based flame retardant (d2), amorphous silica (d3) and antimony trioxide (d4).
It is a cable.

[Appendix 2]
In Appendix 1, preferably
The urethane thermoplastic elastomer (a2) is an adipate type.

[Appendix 3]
In Appendix 1 or 2, preferably
The plasticizer (B) contains a trimellitic acid ester.

[Appendix 4]
In any of Supplementary notes 1 to 3, preferably
The content of the hydrotalcite (c1) is four times or more the content of the metal soap (c2).
The content of the metal soap (c2) is 1.6 parts by mass or less with respect to 100 parts by mass of the polyvinyl chloride resin (a2).

[Appendix 5]
In any of Supplementary notes 1 to 4, preferably
The content of the preplasticizer (B) is 30 parts by mass or more and 95 parts by mass or less with respect to 100 parts by mass of the polyvinyl chloride resin (a1).

[Appendix 6]
In any of Appendix 1-5, preferably
The content of the flame retardant (D) is 5 parts by mass or more and 60 parts by mass or less with respect to 100 parts by mass of the polyvinyl chloride resin (a1).

[Appendix 7]
In any of Supplementary notes 1 to 6, preferably
The content of the urethane thermoplastic elastomer (a2) was X, and the total content of the polyvinyl chloride resin (a1), the plasticizer (B), the stabilizer (C) and the flame retardant (D) was Y. When the ratio X / Y is 5/95 to 70/30.

[Appendix 8]
In any of Supplementary notes 1 to 7, preferably
The thickness of the exodermis layer is 0.1 mm or more and 2 mm or less.

[Appendix 9]
In any of Supplementary notes 1 to 8, preferably
The average degree of polymerization of the polyvinyl chloride resin (a1) is 1000 to 3800.

[Appendix 10]
In any of Appendix 1-9, preferably
The urethane thermoplastic elastomer (a2) has a shore A hardness of 80A to 95A.

[Appendix 11]
Another aspect of the present invention is
A cable including a conductor, an insulating layer coated around the conductor, and an outer skin layer coated around the insulating layer.
The exodermis layer is formed of a flame retardant resin composition containing a base polymer (A), a plasticizer (B), a stabilizer (C) and a flame retardant (D).
The base polymer (A) contains a polyvinyl chloride resin (a1) and at least one urethane thermoplastic elastomer (a2) of adipate-based, lactone-based and carbonate-based, and the content of the urethane thermoplastic elastomer (a2). It is contained so as to be 25 parts by mass or more and 640 parts by mass or less with respect to 100 parts by mass of the polyvinyl chloride resin (a1).
The plasticizer (B) contains a trimellitic acid ester and contains.
The stabilizer (C) contains hydrotalcite (c1) and metal soap (c2).
The flame retardant (D) contains at least one of a metal hydroxide (d1), a bromine-based flame retardant (d2), amorphous silica (d3) and antimony trioxide (d4).
With respect to 100 parts by mass of the polyvinyl chloride resin (a1)
The content of the plasticizer (B) is 30 parts by mass or more and 95 parts by mass or less.
The content of the metal soap (c2) is 1.6 parts by mass or less, and the content of the hydrotalcite (c1) is four times or more the content of the metal soap (c2).
The content of the flame retardant (D) is 5 parts by mass or more and 60 parts by mass or less.
It is a cable.

[Appendix 12]
Yet another aspect of the present invention is
An electric wire provided with a conductor and an insulating layer coated around the conductor.
The insulating layer is formed of a flame retardant resin composition containing a base polymer (A), a plasticizer (B), a stabilizer (C) and a flame retardant (D).
The base polymer (A) contains a polyvinyl chloride resin (a1) and at least one urethane thermoplastic elastomer (a2) of adipate-based, lactone-based and carbonate-based, and the content of the urethane thermoplastic elastomer (a2). It is contained so as to be 25 parts by mass or more and 640 parts by mass or less with respect to 100 parts by mass of the polyvinyl chloride resin (a1).
The stabilizer (C) contains hydrotalcite (c1) and metal soap (c2).
The flame retardant (D) contains at least one of a metal hydroxide (d1), a bromine-based flame retardant (d2), amorphous silica (d3) and antimony trioxide (d4).
It is an electric wire.

1 Cable 10 Electric wire 11 Conductor 12 Insulation layer 13 Shield layer 14 Skin layer (sheath)

Claims (7)

A cable including a conductor, an insulating layer coated around the conductor, and an outer skin layer coated around the insulating layer.
The exodermis layer is formed of a flame retardant resin composition containing a base polymer (A), a plasticizer (B), a stabilizer (C) and a flame retardant (D).
The base polymer (A) contains a polyvinyl chloride resin (a1) and at least one urethane thermoplastic elastomer (a2) of adipate-based, lactone-based and carbonate-based, and the content of the urethane thermoplastic elastomer (a2). It is contained so as to be 25 parts by mass or more and 640 parts by mass or less with respect to 100 parts by mass of the polyvinyl chloride resin (a1).
The stabilizer (C) contains hydrotalcite (c1) and metal soap (c2).
The flame retardant (D) contains at least one of a metal hydroxide (d1), a bromine-based flame retardant (d2), amorphous silica (d3) and antimony trioxide (d4).
cable. The urethane thermoplastic elastomer (a2) is an adipate type.
The cable according to claim 1. The plasticizer (B) contains a trimellitic acid ester.
The cable according to claim 1 or 2. The content of the hydrotalcite (c1) is four times or more the content of the metal soap (c2).
The content of the metal soap (c2) is 1.6 parts by mass or less with respect to 100 parts by mass of the polyvinyl chloride resin (a2).
The cable according to any one of claims 1 to 3. The content of the urethane thermoplastic elastomer (a2) was X, and the total content of the polyvinyl chloride resin (a1), the plasticizer (B), the stabilizer (C) and the flame retardant (D) was Y. When the ratio X / Y is 5/95 to 70/30,
The cable according to any one of claims 1 to 4. The thickness of the exodermis layer is 0.1 mm or more and 2 mm or less.
The cable according to any one of claims 1 to 5. An electric wire provided with a conductor and an insulating layer coated around the conductor.
The insulating layer is formed of a flame retardant resin composition containing a base polymer (A), a plasticizer (B), a stabilizer (C) and a flame retardant (D).
The base polymer (A) contains a polyvinyl chloride resin (a1) and at least one urethane thermoplastic elastomer (a2) of adipate-based, lactone-based and carbonate-based, and the content of the urethane thermoplastic elastomer (a2). It is contained so as to be 25 parts by mass or more and 640 parts by mass or less with respect to 100 parts by mass of the polyvinyl chloride resin (a1).
The stabilizer (C) contains hydrotalcite (c1) and metal soap (c2).
The flame retardant (D) contains at least one of a metal hydroxide (d1), a bromine-based flame retardant (d2), amorphous silica (d3) and antimony trioxide (d4).
Electrical wire.

Images