CN112863734A

CN112863734A - Cable and electric wire

Info

Publication number: CN112863734A
Application number: CN202011083191.4A
Authority: CN
Inventors: 菊池龙太郎; 三浦刚
Original assignee: Hitachi Metals Ltd
Current assignee: Proterial Ltd
Priority date: 2019-11-28
Filing date: 2020-10-12
Publication date: 2021-05-28
Also published as: JP2021086752A; JP7272247B2

Abstract

The invention aims to obtain flame retardancy, heat resistance and recoverability of a cable at a high level and in a balanced manner. The cable comprises a conductor, an insulating layer covering the periphery of the conductor, and an outer skin layer covering the periphery of the insulating layer, wherein the outer skin layer is formed by a flame-retardant resin composition comprising a base polymer (A), a plasticizer (B), a stabilizer (C) and a flame retardant (D), the base polymer (A) comprises chlorinated polyethylene (a1) and at least one polyurethane thermoplastic elastomer (a2) selected from adipate, lactone and carbonate, the stabilizer (C) comprises hydrotalcite (C1) and metal soap (C2), and the flame retardant (D) comprises at least 1 selected from metal hydroxide (D1), bromine flame retardant (D2), amorphous silica (D3) and antimony trioxide (D4).

Description

Cable and electric wire

Technical Field

The present invention relates to a cable and a wire.

Background

A cable is configured by providing an outer sheath (so-called jacket) as a coating material around an electric wire having an insulating layer provided around a conductor, for example. The outer skin layer is formed of a resin composition mainly composed of rubber or resin, and as the 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, a cable for FA robots is required to have flame retardancy, heat resistance, and restorability. In particular, in recent years, the FA robot is configured by a multiaxial articulated type, and a cable used is repeatedly bent along with movement of the device, and thus high resilience is required. The term "restorability" refers to a property of a cable to return to its original shape when the cable is bent.

However, when soft PVC is used for the outer skin layer, the resilience of the outer skin layer is low, and therefore, the cable may be disconnected during operation of the FA robot. Therefore, for a cable requiring restorability, it has been proposed to use a resin composition containing an ether polyurethane thermoplastic elastomer (hereinafter, also simply referred to as TPU) in soft PVC (for example, see patent document 1), and the TPU can impart restorability to the outer skin layer.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2016-91975

Disclosure of Invention

Problems to be solved by the invention

However, even if TPU is added to the outer skin layer, flame retardancy, heat resistance, and recovery may not be obtained in a well-balanced manner at a high level. Specifically, in the outer skin layer, a large amount of a flame retardant is added to obtain high flame retardancy, and the large amount of the flame retardant causes a hard segment of the TPU to collapse, thereby impairing the heat resistance inherent in the TPU. On the other hand, if the amount of the flame retardant to be added is reduced in order to obtain heat resistance by the TPU, desired flame retardancy may not be obtained. Thus, when TPU is used, although high restorability can be obtained, it is not possible to maintain both flame retardancy and heat resistance at a high level.

Further, the outer skin layer is required to have cold resistance such that it exhibits appropriate elasticity even in a low-temperature environment, but when TPU is blended, sufficient cold resistance may not be obtained.

The purpose of the present invention is to provide a technique for achieving flame retardancy, heat resistance, recovery, and cold resistance of a cable at a high level and in a balanced manner.

Means for solving the problems

According to one aspect of the present invention, there is provided a cable comprising a conductor, an insulating layer covering a periphery of the conductor, and a sheath layer covering a periphery of the insulating layer,

the outer skin layer is formed from a flame-retardant resin composition comprising a base polymer (A), a plasticizer (B), a stabilizer (C) and a flame retardant (D),

the base polymer (A) comprises a chlorinated polyethylene (a1) and at least 1 polyurethane thermoplastic elastomer (a2) selected from the group consisting of adipate-based, lactone-based and carbonate-based polyurethane thermoplastic elastomers,

the stabilizer (C) comprises hydrotalcite (C1) and metal soap (C2),

the flame retardant (D) contains at least 1 of a metal hydroxide (D1), a bromine-based flame retardant (D2), amorphous silica (D3) and antimony trioxide (D4).

According to another aspect of the present invention, there is provided an electric wire including a conductor and an insulating layer covering a periphery of the conductor,

the insulating layer is formed from a flame-retardant resin composition containing a base polymer (A), a plasticizer (B), a stabilizer (C) and a flame retardant (D),

the stabilizer (C) comprises hydrotalcite (C1) and metal soap (C2),

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, the cable can be made to have flame retardancy, heat resistance, restorability, and cold resistance in a high level and well-balanced manner.

Drawings

Fig. 1 is a cross-sectional view of a cable perpendicular to a longitudinal direction according to an embodiment of the present invention.

Description of the symbols

1: cable, 10: electric wire, 11: conductor, 12: insulating layer, 13: shielding layer, 14: outer skin layer (jacket).

Detailed Description

< recognition by the present inventors et al >

As described above, when TPU is mixed with soft PVC, a large amount of additives such as a flame retardant are incorporated into TPU, and heat resistance is lowered. In addition, the desired cold resistance may not be obtained in the case of a blend of soft PVC and TPU. Therefore, the present inventors have studied on the kind of a component that replaces PVC as a base polymer and a plasticizer, a stabilizer, and a flame retardant added thereto.

As a result, it has been found that it is preferable to use chlorinated polyethylene (hereinafter, also referred to as CPE) and TPU together as a base polymer from the viewpoint of obtaining flame retardancy, heat resistance, restorability, and cold resistance at a high level in a well-balanced manner.

Further, as the stabilizer, hydrotalcite and metal soap are preferable because they are easily selectively dispersed in CPE, and as the flame retardant, at least 1 of metal hydroxide, bromine-based flame retardant, amorphous silica and antimony trioxide is preferably used because they are easily selectively dispersed in CPE.

On the other hand, in order to improve the heat resistance of the outer skin layer, studies have been made on TPU, and it has been found that among TPU, adipate-based, lactone-based and carbonate-based TPU is preferable. In general, TPUs are obtained by the reaction of polyols, diols and isocyanates, with hard, rigid hard segments and soft segments. The TPU includes a polyester TPU using a polyester polyol as a polyol and a polyether TPU using a polyether polyol as a polyol. According to the studies of the present inventors, a polyester TPU is desired from the viewpoint of heat resistance. Further, it is known that there are many polyester TPUs depending on the kind of polyester polyol, but from the viewpoint of various characteristics, adipate type, lactone type and carbonate type are desirable.

According to such a combination of materials, since additives such as a stabilizer and a flame retardant can be selectively dispersed in CPE, not only can the characteristics of CPE and TPU be utilized flexibly, but also the decrease in heat resistance due to the addition of a large amount of additives can be suppressed and the cold resistance can be improved. As a result, flame retardancy, heat resistance, recovery properties and cold resistance can be obtained at a high level in a well-balanced manner.

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

< one embodiment of the present invention >

Hereinafter, a cable according to an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a cross-sectional view of a cable perpendicular to a longitudinal direction according to an embodiment of the present invention. In the present specification, the numerical range expressed by the term "to" means a range including the numerical values described before and after the term "to" as the lower limit value and the upper limit value.

(flame-retardant resin composition)

First, a flame-retardant resin composition for forming an outer sheath of a 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 other additives as needed. Specifically, the base polymer (a) contains a chlorinated polyethylene (a1) and at least 1 polyurethane thermoplastic elastomer (a2) of adipate series, lactone series and carbonate series. The stabilizer (C) comprises hydrotalcite (C1) and metal soap (C2). The flame retardant (D) contains at least 1 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, as the base polymer (a), chlorinated polyethylene (a1) and at least 1 kind of urethane thermoplastic elastomer (a2) of adipate series, lactone series and carbonate series are used.

The chlorinated polyethylene (a1) is a component contributing to improvement in flame retardancy and cold resistance of the outer skin layer. The chlorinated polyethylene (a1) was obtained by blowing chlorine gas into an aqueous suspension obtained by suspending and dispersing raw material polyethylene in water.

The chlorine content of CPE (a1) is not particularly limited, but is preferably 20% or more, and more preferably 20% to 45%, from the viewpoint of improving cold resistance and flame retardancy. In addition, a plurality of CPEs having different chlorine contents may be used in combination with CPE (a 1).

The polyurethane thermoplastic elastomer (a2) is a component that imparts recoverability mainly to the outer skin layer. The thermoplastic polyurethane elastomer (a2) according to the present embodiment is an adipate-based, lactone-based or carbonate-based elastomer. Adipate esters are TPUs obtained by reaction of adipic acid-based polyester polyols and diols with isocyanates. Lactones are, for example, TPUs obtained from the reaction of polyester polyols of caprolactam type with diols, isocyanates. The carbonate ester is, for example, a TPU obtained by reacting a polycarbonate compound type polyester polyol with a diol and 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, 1, 8-octanediol, 1, 9-nonanediol, neopentyl glycol, 2-butyl-2-ethyl-1, 3-propanediol, 3-methyl-1, 5-pentanediol, 2-methyl-1, 3-propanediol, 3, 5-trimethylpentanediol, 2, 4-diethyl-1, 5-pentanediol, 1, 12-octadecanediol, 1, 2-alkanediol, 1, 3-alkanediol, 1-monoglyceride, 2-monoglyceride, 1-monoglyceride ether, 2-monoglyceride ether, 1, 3-monoglyceride ether, 1, 4-butanediol, 1, 4-pentanediol ether, 1, 3-pentanediol ether, 1-methyl-1, 5-pentanediol ether, 1, 3-pentanediol ether, 2-diglyceride, diols, hydrogenated diols, and the like.

As the isocyanate, a known component can be used. Examples thereof include aliphatic diisocyanates such as hexamethylene diisocyanate, butane-1, 4-diisocyanate, 2, 4-trimethylhexamethylene diisocyanate, 2,4, 4-trimethylhexamethylene diisocyanate, xylylene diisocyanate and m-tetramethylxylylene diisocyanate. Further, alicyclic diisocyanates such as isophorone diisocyanate, cyclohexane-1, 4-diisocyanate, lysine diisocyanate, dicyclohexylmethane-4, 4 ' -diisocyanate, 1, 3-bis (isocyanatomethyl) cyclohexane, methylcyclohexane diisocyanate, 4 ' -dicyclohexylmethane diisocyanate, isopropylidene dicyclohexyl-4, 4 ' -diisocyanate, norbornane diisocyanate and the like can be mentioned. Further, aromatic diisocyanates such as 1, 5-naphthylene diisocyanate, 4 ' -diphenylmethane diisocyanate, 4 ' -diphenyldimethylmethane diisocyanate, 4 ' -dibenzyl diisocyanate, dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, 1, 3-phenylene diisocyanate, 1, 4-phenylene diisocyanate, toluene diisocyanate, and tetramethylxylylene diisocyanate are exemplified.

The TPU (a2) is not particularly limited as long as it is an adipate type, an lactone type and a carbonate type from the viewpoint of the heat resistance of the outer skin layer, and is preferably an adipate type from the viewpoint of adjusting the hardness of the outer skin layer. The adipate type is excellent not only in hardness adjustment but also in affinity with the polyvinyl chloride resin (a1) as compared with the lactone type and carbonate type, and the flame retardant resin composition constituting the outer skin layer is likely to form a phase structure described later, and can more stably realize various properties at a high level. This is because: since the adipate TPU has a structure derived from adipic acid, even when an additive is added, the bonding force of a hydrogen bond or a urethane bond in a hard segment is not significantly impaired, and the properties can be easily maintained high.

The hardness of the adipate TPU (a2) is not particularly limited, and from the viewpoint of the balance between the recovery property of the outer skin layer and the heat resistance, the shore a hardness is preferably 80A to 95A, more preferably 80A to 90A.

The base polymer (a) may contain a polymer component other than the above-mentioned component (a1) and component (a2) within a range not impairing the properties of the outer skin layer. For example, a polyvinyl chloride resin, an ethylene-vinyl chloride copolymer, an ethylene-vinyl acetate copolymer, a styrene-based elastomer, an ethylene- α -olefin copolymer, an ethylene-acrylic acid ester copolymer, an acrylic resin, or a modified product thereof, or the like can be used. Among them, the polyvinyl chloride resin (a3) (hereinafter, also simply referred to as PVC (a3)) is preferable from the viewpoint of having excellent affinity with CPE (a1) and TPU (a2) and obtaining various properties at a higher level.

As the polyvinyl chloride resin (a3), in addition to 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 or a copolymer with vinyl acetate or the like can be used. Further, as the PVC (a3), a compound partially crosslinked may be used.

The average polymerization degree of the polyvinyl chloride resin (a3) is not particularly limited, but is preferably 1000 to 3800, and more preferably 1300 to 2500. By setting the average polymerization degree to 1000 or more, the outer skin layer can obtain high heat resistance. On the other hand, if the average polymerization degree is excessively increased, the moldability of the flame-retardant resin composition may be lowered, and by setting the average polymerization degree to 3800 or less, the heat resistance of the outer skin layer can be improved without impairing the moldability. Further, as PVC (a3), a plurality of compounds having different average polymerization degrees may be used in combination.

(plasticizer (B))

The plasticizer (B) is a component for imparting flexibility to the outer skin layer. As the plasticizer (B), known components such as trimellitic ester, phthalic ester, and adipic acid polyester can be used. Among them, trimellitate is preferable because it does not impair the characteristics of the outer skin layer. Trimellitic esters can maintain the heat resistance of the outer skin layer higher than phthalic esters. Further, the outer skin layer is not tacky as compared with adipic acid polyester, and therefore, the workability of the cable can be improved. Trimellitate ester may be used alone or in combination with, for example, adipic acid polyester within a range not impairing the characteristics of the outer skin layer.

Examples of the trimellitic acid ester include tri (2-ethylhexyl) trimellitate, tri-n-octyl trimellitate, tribasic alkyl trimellitate, and triisononyl trimellitate.

(stabilizer (C))

The stabilizer (C) functions as a heat stabilizer for inhibiting the deterioration of CPE (a1) and PVC (a3) when preparing the flame-retardant resin composition, and is a component for stabilizing the phase structure of the flame-retardant resin composition. In the present embodiment, in the case of CPE (a1) or PVC (a3) in combination, hydrotalcite (c1) and metal soap (c2) are used from the viewpoint of selectively dispersing both components. The hydrotalcite (c1) and the metal soap (c2) are not particularly limited as long as they have excellent compatibility with CPE (a1) and PVC (a3), and known components can be used. As the metal soap (c2), for example, a component composed of a fatty acid such as stearic acid, lauric acid, or caprylic acid and a metal such as calcium or 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 which does not affect whether or not the TPU (a2) is added, and acts only on the polyvinyl chloride resin (a 1). As the stabilizing aid, for example, dibenzoylmethane, stearylbenzoylmethane and metal salts thereof, polyhydric alcohols, trihydroxyethyl isocyanate, silica, calcium carbonate, antioxidants, talc, clay and the like can be used in an appropriate amount as required.

(flame retardant (D))

The flame retardant (D) is a component for imparting flame retardancy to the outer skin layer. In the present embodiment, at least 1 of the metal hydroxide (D1), the bromine-based flame retardant (D2), the amorphous silica (D3), and the antimony trioxide (D4) is used as the flame retardant (D) from the viewpoint of dispersing the additive in the chlorinated polyethylene (a1) or, in the case of using the polyvinyl chloride resin (a3) in combination, from the viewpoint of selectively dispersing the additive in both of the CPE (a1) and the PVC (a 3).

As the metal hydroxide (d1), for example, magnesium hydroxide, aluminum hydroxide, or the like can be used. Among them, aluminum hydroxide is particularly preferable. In the case of magnesium hydroxide, the basicity of the flame-retardant resin composition increases, and the urethane bond strength, hydrogen bond strength, ester bond strength, and the like in the hard segment of the TPU decrease, and the heat resistance of the TPU may be impaired. In this regard, aluminum hydroxide can maintain high heat resistance without excessively increasing the basicity. The metal hydroxide (d1) may not be subjected to surface treatment, and may be subjected to surface treatment such as silane treatment. From the viewpoint of dispersibility, the average particle diameter of the metal hydroxide (d1) is preferably 5 μm or less. The lower limit is not particularly limited, and is, for example, 0.2. mu.m.

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

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

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

(other additives)

In the flame-retardant resin composition, other additives may be added as necessary in addition to the components (A) to (D). As other additives, for example, a crosslinking aid, an antioxidant (heat aging inhibitor), a copper corrosion inhibitor, a lubricant, a processing aid, or the like can be used.

Specifically, examples of the crosslinking assistant include trimethylolpropane trimethacrylate (TMPT), triallylisocyanurate, triallylcyanurate, N' -m-phenylene bismaleimide, ethylene glycol dimethacrylate, zinc acrylate and zinc methacrylate.

Further, examples of the antioxidant include a phenol-based antioxidant, a phosphorus-based antioxidant, and a sulfur-based antioxidant. Examples of the copper corrosion inhibitor include N- (2H-1,2, 4-triazol-5-yl) salicylamide, dodecanedioic acid bis [ N2- (2-hydroxybenzoyl) hydrazide ], 2 ', 3-bis [ [3- [3, 5-di-t-butyl-4-hydroxyphenyl ] propionyl ] propanehydrazide and the like, and more preferably, 2', 3-bis [ [3- [3, 5-di-t-butyl-4-hydroxyphenyl ] propionyl ] propanehydrazide.

Examples of the lubricant include hydrocarbon-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, and polymethyl methacrylate.

(photo structure)

In the flame-retardant resin composition of the present embodiment, the chlorinated polyethylene (a1) and the TPU (a2) are dispersed in one component in the other component to form a sea-island structure or to be unstably dispersed. Further, since the stabilizer (C) and the flame retardant (D) are more easily selectively dispersed in CPE (a1) than TPU (a2), the amount of the additive incorporated into TPU (a2) is reduced, and thus the reduction of urethane bond strength and hydrogen bond strength in the (a2) component can be suppressed. This can maintain the original properties of component (a2) high.

In addition, when the polyvinyl chloride resin (a3) is further added as the base polymer (a), a clear sea-island structure tends not to be formed, as compared with the case of using CPE (a1) and TPU (a 2). In addition, it was confirmed that the additive was more selectively dispersed in CPE (a1) and PVC (a3) than TPU (a2) and the degree of dispersion was decreased. Further, it was confirmed that by using PVC (a3) in combination, each characteristic can be stably obtained with a high level of balance. The mechanism by which this characteristic can be obtained is not clear, but it is presumed that the compatibility between the chlorinated polyethylene (a1) and the polyvinyl chloride resin (a3) is high, and a finer and specific phase structure is formed by mixing these 3 components.

(containing ratio)

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

First, when the chlorinated polyethylene (a1) and TPU (a2) are used as the base polymer (a), the following content ratios are preferable.

The base polymer (a) preferably contains 6 to 620 parts by mass of TPU per 100 parts by mass of the chlorinated polyethylene (a1), and more preferably contains 15 to 200 parts by mass. By mixing in such a ratio, the above-described phase structure is easily formed, and desired characteristics are easily obtained.

The content of the chlorinated polyethylene (a1) in the flame-retardant resin composition is preferably 2% to 60%. By adding the (a1) component at such a ratio, the outer skin layer can obtain the characteristics well balanced at a higher level.

The content of the plasticizer (B) is not particularly limited, and if it is excessively small, when CPE (a1) and TPU (a2) are mixed, not only the recovery property is lowered and the respective properties cannot be obtained in a well-balanced manner, but also the molding processability and the cold resistance may be lowered. If the amount of the flame retardant is excessively large, the adhesiveness of the outer skin layer may be increased, and the moldability and flame retardancy may be lowered. The content of the plasticizer (B) is preferably 2 to 60 parts by mass with respect to 100 parts by mass of the CPE (a1) from the viewpoint of obtaining the properties of the outer skin layer in a high level and well-balanced manner.

The content of the stabilizer (C) is not particularly limited, and the metal soap (C2) may lower the hydrogen bonding force and the urethane bonding force in the hard segment of the TPU (a2) more easily than the hydrotalcite (C1), and may impair the heat resistance of the outer skin layer. Therefore, from the viewpoint of stabilizing the chlorinated polyethylene (a1) and maintaining the heat resistance high, it is preferable to reduce the content of the metal soap (C2), and to increase the content of the hydrotalcite (C1) in order to ensure the effect of the stabilizer (C). Specifically, the content of the metal soap (c2) is preferably 1.6 parts by mass or less based on 100 parts by mass of the chlorinated polyethylene (a1), and the content of the hydrotalcite (c1) is preferably 4 times or more of the content of the metal soap (c 2). The lower limit of the content of the metal soap (c2) is not particularly limited, and if it is excessively small, the flame-retardant resin composition is colored or the properties thereof are deteriorated, and therefore, it is preferably 0.01 part by mass or more. The content of the hydrotalcite (c1) is not particularly limited, and is preferably 10 to 120 parts by mass with respect to 100 parts by mass of CPE (a 1). The total content of the stabilizers (C) is preferably 2 to 20 parts by mass.

The content of the flame retardant (D) is not particularly limited, and the total content of (D1) to (D4) is preferably 1 to 70 parts by mass with respect to 100 parts by mass of the chlorinated polyethylene (a 1). The total amount of the contents of (d1) to (d4) is not particularly limited as long as it is within the above range, but is preferably within the following range. (d1) 0 to 50 parts by mass, (d2) 0 to 50 parts by mass, (d3) 0 to 40 parts by mass, and (d4) 0 to 50 parts by mass.

Next, when the chlorinated polyethylene (a1), TPU (a2) and polyvinyl chloride resin (a3) are used as the base polymer (a), the following content ratios are preferably set.

The base polymer (a) preferably contains 20 to 1700 parts by mass of TPU (a2) and 3 to 900 parts by mass of polyvinyl chloride resin (a3) per 100 parts by mass of chlorinated polyethylene (a 1). More preferably, the thermoplastic polyurethane composition comprises 30 to 1700 parts by mass of TPU (a2) and 4 to 900 parts by mass of PVC (a 3).

When a compound other than the polyvinyl chloride resin (a3) is used as the other polymer, the amount of the compound added is preferably in the same range as that of PVC (a 3).

The respective contents of the plasticizer (B), the stabilizer (C) and the flame retardant (D) are preferably in the following ranges with respect to 100 parts by mass of the chlorinated polyethylene (a 1). That is, the content of the plasticizer (B) is preferably 2 to 600 parts by mass, the content of the stabilizer (C) is preferably 5 to 150 parts by mass, and the content of the flame retardant (D) is preferably 5 to 350 parts by mass. The content of the metal soap (c2) is preferably 1 to 21 parts by mass. The content of the hydrotalcite (c1) is preferably 4 times or more, and preferably 10 to 120 parts by mass, the content of the metal soap (c 2). Further, the components (D1) to (D4) of the flame retardant (D) are preferably 0 to 100 parts by mass of (D1), 0 to 50 parts by mass of (D2), 0 to 50 parts by mass of (D3) and 0 to 100 parts by mass of (D4).

(preparation of flame-retardant resin composition)

The flame-retardant resin composition is preferably prepared by mixing and melt-kneading the above-mentioned components (A) to (D) and, if necessary, other additives. The kneading is preferably carried out using a known kneading apparatus such as a batch kneader such as a Banbury mixer or a pressure kneader, a continuous kneader such as a twin-screw extruder, or the like.

Specifically, first, the chlorinated polyethylene (a1), the plasticizer (B), the stabilizer (C), and the flame retardant (D) are kneaded to obtain CPE particles. Subsequently, the obtained CPE pellets were mixed with TPU (a2) and melt-kneaded. This enables the flame-retardant resin composition to be formed by dispersing the TPU (a2) in the CPE mixture or dispersing the CPE mixture in the TPU (a 2). In the flame-retardant resin composition, the incorporation of the additive into the phase of the TPU (a2) can be reduced by preparing CPE particles in advance. This can maintain the heat resistance of the outer skin layer higher.

When the polyvinyl chloride resin (a3) is used, it is preferably blended with CPE (a1) and molded into pellets, and then TPU (a2) is blended. Further, the plasticizer (B) may be a powder product in which CPE (a1) is mixed in a powder state in which it has affinity with PVC (a3) and a stabilizer (C) or the like is dispersed, or TPU (a2) may be mixed and kneaded in pellets obtained by melt-kneading these components. In this case, the generation of a sticky lump when the CPE (a1) and the plasticizer (B) are brought into contact can be appropriately suppressed, and the material supply property can be improved.

Even when the respective materials are mixed and melt-kneaded, since CPE (a1) and PVC (a3) melt at a lower temperature than TPU (a2), the respective additives are more easily dispersed in the (a1) component and the (a3) component than the (a2) component, but as described above, the incorporation of the additives into the (a2) component can be further reduced by preparing CPE particles in advance.

(Cable)

Next, the cable according to the present embodiment will be described with reference to fig. 1. Fig. 1 is a cross-sectional view of a cable perpendicular to a longitudinal direction according to an embodiment of the present invention.

As shown in fig. 1, the cable 1 of the present embodiment includes: the electric wire 10 includes an insulating layer 12 formed around a conductor 11, a shield layer 13 provided around the electric wire 10, and an outer sheath layer 14 (jacket 14) formed around the shield layer 13.

(conductor)

As the conductor 11, besides a metal wire that is generally used, for example, a copper wire or a copper alloy wire, an aluminum wire, a gold wire, a silver wire, or the like can be used. As the conductor 11, a conductor plated with a metal such as tin or nickel around a metal wire can be used. Further, as the conductor 11, a twisted wire obtained by twisting a metal wire can be used.

(insulating layer)

The insulating layer 12 is provided around the conductor 11. The insulating layer 12 may be formed of a mixture to which a conventionally known material, for example, a fluororesin, a polyester resin, high-density polyethylene, a flame retardant, an antioxidant, or the like is added, or may be formed of a flame-retardant resin composition for forming the outer skin layer. The thickness of the insulating layer 12 is not particularly limited, and is preferably 0.1mm to 1.5mm, for example.

(Shielding layer)

The shield layer 13 is provided around a twisted wire obtained by twisting a plurality of electric wires 10. The shield layer 13 is formed of a braided structure obtained by braiding a plurality of metal wires such as annealed copper wires.

(outer skin layer)

The outer skin layer 14 is provided around the shield layer 13 and is formed of the flame-retardant resin composition. The thickness of the outer skin layer 14 is not particularly limited, and is preferably 0.1mm to 1.4mm from the viewpoint of obtaining various properties in a high level of balance.

The flame-retardant resin composition may be crosslinked from the viewpoint of improving the oil resistance of the outer skin layer 14 and the flame-out stability during combustion. The crosslinking method is not particularly limited, and electron beam crosslinking, for example, can be employed. When electron beam crosslinking is performed, the flame-retardant resin composition is preferably crosslinked by irradiating the flame-retardant resin composition to be extruded with an electron beam of 0.5 to 30 Mrad.

(method of manufacturing Cable)

First, a conductor 11 is prepared, and the flame-retardant resin composition is coated around the conductor 11 and extruded by an extrusion molding machine to form an insulating layer 12 having a predetermined thickness, thereby obtaining an electric wire 10. Next, the plurality of wires 10 are twisted together, and a shield layer 13 is formed around the twisted wires by a knitting machine. Next, the flame-retardant resin composition is extruded by an extrusion molding machine so as to cover the periphery of the shield layer 13, thereby forming the outer skin layer 14 having a predetermined thickness. Thereby, the cable 1 of the present embodiment can be manufactured.

< Effect of the present embodiment >

According to the present embodiment, 1 or more effects shown below are achieved.

According to the cable 1 of the present embodiment, the flame-retardant resin composition forming the outer skin layer 14 contains, as the base polymer (a), chlorinated polyethylene (a1) and at least 1 kind of urethane thermoplastic elastomer (a2) of adipate series, lactone series and carbonate series, and contains at least 1 of hydrotalcite (C1) and metal soap (C2) as the stabilizer (C), metal hydroxide (D1) as the flame retardant (D), bromine series flame retardant (D2), amorphous silica (D3) and antimony trioxide (D4) as the flame retardant (D). (C) Component (D) and component (D) can reduce the entry of additives into TPU (a2) because they are more easily selectively dispersed in chlorinated polyethylene (a1) than TPU (a 2). Therefore, the decrease in urethane bonding force and hydrogen bonding force due to the incorporation of the additive in the component (a2) can be suppressed. As a result, not only the recovery property due to the component (a2) can be obtained, but also the heat resistance of the outer skin layer 14 can be maintained high. Further, since at least 1 (a2) component of adipate, lactone, and carbonate is used as the TPU, the heat resistance of the outer skin layer 14 can be maintained higher. Further, the combination of the plasticizer (B) and the stabilizer (C) can maintain the properties inherent in the component (a1) and the component (a2) at a high level without causing a large damage. Further, according to the flame retardant (D), the flame retardancy of the outer skin layer 14 can be improved. Therefore, according to the cable 1 of the present embodiment, the restorability, the heat resistance, the flame retardancy, and the cold resistance can be obtained in a well-balanced manner at a high level.

Specifically, the cable 1 of the present embodiment has high flame retardancy that can be passed the vertical flame retardancy test VW-1 defined in the flame retardancy standard UL 1581. Further, the heat resistance is high enough to satisfy the 105 ℃ rating in the UL standard. Further, the cable has high restorability such that the cable is not broken when used as a cable for an FA robot. Further, the steel sheet has high cold resistance such that it does not break even at-50 ℃ in an embrittlement test described later.

Further, the flame-retardant resin composition can achieve flame retardancy, heat resistance, restorability, and cold resistance in a balanced and stable manner at a higher level by further comprising the polyvinyl chloride resin (a3) as the base polymer (a).

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

The plasticizer (B) is preferably trimellitic ester. The trimellitic ester can maintain high heat resistance of the outer skin layer.

The content of the plasticizer (B) is preferably 2 to 60 parts by mass with respect to 100 parts by mass of CPE (a 1). When PVC (a3) is used in combination, it is preferably 2 to 600 parts by mass per 100 parts by mass of CPE (a 1). By using such a content, the heat resistance, flame retardancy, and recovery of the outer skin layer can be maintained higher.

The content of the flame retardant (D) is preferably 1 to 70 parts by mass with respect to 100 parts by mass of the CPE (a 1). When PVC (a3) is used in combination, it is preferably 5 to 350 parts by mass per 100 parts by mass of CPE (a 1). By using such a content, the heat resistance, flame retardancy, and recovery of the outer skin layer can be maintained higher.

It is preferable that the content of the hydrotalcite (c1) is 4 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 per 100 parts by mass of CPE (a1), and the content of the hydrotalcite (c1) is 10 to 120 parts by mass. When PVC (a3) is used in combination, it is preferable that the content of the metal soap (c2) is 21 parts by mass or less and the content of the hydrotalcite (c1) is 10 to 120 parts by mass with respect to 100 parts by mass of CPE (a 1). This can suppress a decrease in the hydrogen bonding force or urethane bonding force of the TPU (a2), and can maintain the heat resistance of the outer skin layer 14 high.

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

The content of the chlorinated polyethylene (a1) in the flame-retardant resin composition is preferably 2% to 60%. By containing the component (a1) in such a ratio, the outer skin layer 14 can be made to have various properties in a more balanced manner.

Further, the chlorine content of the chlorinated polyethylene (a1) is preferably 20% or more. According to such a chlorinated polyethylene (a1), since the balance between flame retardancy and cold resistance is excellent, the outer skin layer 14 can be made to have various properties in a balanced manner at a higher level.

In addition, in the present embodiment, since 2 components (a1) and (a2) as the base polymer (a) are used together to form the polymer alloy, a desired unevenness can be provided to the surface of the outer skin layer 14. This can reduce the surface friction resistance of the cable 1.

In the present embodiment, the case where the flame-retardant resin composition is used for the outer sheath layer of a cable has been described, but the present invention is not limited thereto. For example, the flame-retardant resin composition can also be used for an insulating layer of an electric wire.

Examples

The present invention will be described in more detail below with reference to 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 outer skin layer were as follows.

As the chlorinated polyethylene (a1), the following was used.

34 to 37 percent of chlorinated polyethylene 1 (product name "Elaslen 352 GB", manufactured by Showa Denko K.K., chlorine content)

30 to 33% of chlorinated polyethylene 2 (product name "Elaslen 301A", manufactured by Showa Denko K.K., chlorine content)

38% -41% of chlorinated polyethylene 3 (product name "Elaslen 401A", manufactured by Showa Denko K.K., chlorine content)

As the adipate type urethane thermoplastic elastomer (a2), the following was used.

Adipate type TPU1 (product name "P25 MRWJE", Miractran, Japan, Shore A hardness 90)

As the polymer components other than the above-mentioned component (a1) and component (a2), the following are used.

As the polyvinyl chloride resin (a3), the following was used.

Polyvinyl chloride resin 1 (product name "TH-1700", manufactured by Dayo vinyl chloride Co., Ltd., average polymerization degree 1600-

As components other than the component (a3), the following were used.

Ethylene-vinyl chloride copolymer (product name "TE-1300", manufactured by Water accumulation chemical Co., Ltd.)

Styrene elastomer (product name "S.O.ES1606", manufactured by Asahi Kasei chemical Co., Ltd.)

Ethylene-alpha olefin copolymer (product name "TAFMER DF 540", manufactured by Mitsui chemical Co., Ltd.)

Modified ethylene-alpha olefin copolymer (product name "TAFMER MH 7020", manufactured by Mitsui chemical Co., Ltd.)

Ethylene-vinyl acetate copolymer EVA1 (product name "45 LX", manufactured by Mitsui DuPont Polymer chemical Co., Ltd.)

Ethylene-vinyl acetate copolymer EVA2 (product name "Levapren 500", manufactured by Langsheng Co., Ltd.)

Ethylene-ethyl acrylate copolymer EEA (product name "REXPEARL 1150", manufactured by Mitsubishi chemical corporation)

Acrylic resin (polymethyl methacrylate resin PMMA) (product name "METABLEN P1050", manufactured by Mitsubishi chemical corporation)

As the plasticizer (B), the following was used.

Tri (2-ethylhexyl) trimellitate (TOTM) (product name "T08", manufactured by Kao corporation)

Trioctyl trimellitate (N-TOTM) (product name "N08", manufactured by Kao corporation)

Adipic acid polyester (product name "P1030", manufactured by ADEKA K.K.)

As the hydrotalcite (C1) as the stabilizer (C), the following ones were used.

Hydrotalcite (made by Sakai chemical Co., Ltd. "HT-1")

As the metal soap (C2) of the stabilizer (C), the following was used.

Zinc stearate (made by Sakai Kabushiki Kaisha "SZ-P")

Calcium stearate (made by Sakai Kagaku corporation, brand name "SC-P")

As other components of the stabilizer (C), the following were used.

Stabilizing aids (containing beta-diketones, etc.)

As the metal hydroxide (D1) of the flame retardant (D), the following were used.

Untreated aluminum hydroxide (product name "BF 013", manufactured by Nippon light Metal Co., Ltd.)

Silane-treated aluminum hydroxide (product name "BF 013 STV", manufactured by Nippon light Metal Co., Ltd.)

The following were used as the bromine-based flame retardant (D2) as the flame retardant (D).

Bromine-containing flame retardant (decabromodiphenylethane, product name "Saytex 8010", product of Yao Kabushiki Kaisha, average particle size 5.6 μm)

As the amorphous silica (D3) as the flame retardant (D), the following was used.

Amorphous silica (product name "SIDISTAR 120U", product name of Eken corporation, average particle diameter 0.15 μm)

Antimony trioxide (D4) as the flame retardant (D) used were as follows.

Antimony trioxide (product name "NANO 200", manufactured by Hendebi corporation, average particle diameter 0.8 μm)

As other additives, the following were used.

Crosslinking aid (trimethylolpropane trimethacrylate, product name "TMPT", manufactured by Xinzhongcun chemical Co., Ltd.)

Calcined Clay (product name "SP # 33", manufactured by BASF corporation)

Black colorant (product name "NBP 2425", manufactured by Nichihong VICS Co., Ltd.)

White colorant (product name "titanium white R820", product of Shiyu Kabushiki Kaisha)

Antioxidant (product name "AO-26", manufactured by ADEKA Co., Ltd.)

< example 1 >

First, a conductor, a resin composition for forming an insulating layer, and a flame-retardant resin composition for forming an outer skin layer are prepared.

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

As the resin composition for forming the insulating layer, a composition containing ETFE (ethylene tetrafluoride-ethylene copolymer) as a fluororesin is used.

The flame-retardant resin composition for forming the outer layer was prepared by mixing and kneading the above materials so as to have the compositions shown in table 1 below. Specifically, 100 parts by mass of chlorinated polyethylene 1 and 41.8 parts by mass of adipate-type TPU1 as a base polymer (a), 30.0 parts by mass of TOTM as a plasticizer (B), 11.66 parts by mass of hydrotalcite (C1) as a stabilizer (C), 1.14 parts by mass of zinc stearate as a metal soap (C2), 1.2 parts by mass of a stabilizing aid, 5.0 parts by mass of untreated aluminum hydroxide belonging to a metal hydroxide (D1) and 8.0 parts by mass of antimony trioxide (D4) as a flame retardant (D), and 1.0 part by mass of a crosslinking aid, 5.2 parts by mass of calcined clay, 3.5 parts by mass of a black colorant, and 0.5 part by mass of a white colorant as other additives were kneaded in total 209.0 parts by mass to prepare the flame-retardant resin composition of example 1. In example 1, the chlorinated polyethylene (a1) was prepared so that the ratio ((a 1)/total amount) of the chlorinated polyethylene in the flame-retardant resin composition was 0.48. The flame-retardant resin composition was prepared by melt-kneading at a take-out temperature of 165 ℃ using a pressure kneader, cutting the strand, and then drying at 80 ℃ for 2 hours.

Then, a resin composition for forming an insulating layer was extruded around the conductor using a 40mm extruder for manufacturing an electric wire, thereby forming an insulating layer having a thickness of 0.2 mm. Thereby obtaining the electric wire. Then, 5 wires were twisted, and the rayon and the polyester tape (1/4 turns) were twisted around them using a knitting machine (right twist), thereby forming a shield layer. Subsequently, the flame-retardant resin composition was extruded around the shield layer by a tube extrusion method using a 65mm single-shaft extruder for manufacturing electric wires, thereby forming an outer skin layer having a thickness of 1 mm. Thus, the cable of example 1 was produced.

[ Table 1]

< examples 2 to 6 >

Cables were produced in the same manner as in example 1 except that the types and amounts of components (a) to (D) were changed as appropriate as shown in table 1 in examples 2 to 6.

< comparative examples 1 to 3 >

In comparative examples 1 and 2, cables were produced in the same manner as in example 1 except that an adipate TPU (a2) and a polyvinyl chloride resin (a3) were used instead of the chlorinated polyethylene (a1) as shown in table 1. A cable was produced in the same manner as in example 1, except that in comparative example 3, the chlorinated polyethylene (a1) and the flame retardant (D) were not used.

< examples 7 to 17 >

In examples 7 to 17, cables were produced in the same manner as in example 1, except that the content of each component was changed as appropriate using chlorinated polyethylene (a1), adipate TPU (a2) and polyvinyl chloride resin (a3) as shown in table 2 below.

< examples 18 to 22 >

Cables were produced in the same manner as in example 1, except that the polymer components in examples 18 to 22 were changed to those shown in table 2 instead of the polyvinyl chloride resin (a 3).

[ Table 2]

< evaluation >

The cables of examples 1 to 22 and comparative examples 1 to 3 were evaluated for heat resistance, flame retardancy, restorability, and cold resistance. Each evaluation was performed as follows.

(Heat resistance)

The heat resistance was evaluated by a test according to UL 1581. Specifically, a sample (about 100mm in length) of only the outer skin layer was made from the cable produced, and the sample was exposed in a Gill aging oven at 136 ℃ for 168 hours, and the initial tensile strength and elongation were compared with those after exposure. Then, the tensile strength residual rate (%) and the elongation residual rate (%) were calculated by the following formula, and the case where the tensile strength residual rate was 70% or more and the elongation residual rate was 45% or more was regarded as "pass", and the case where either one of them was not satisfied or the case where neither of them was satisfied was regarded as "fail".

Tensile strength residual ratio (%) < 100 × (tensile strength after exposure)/(initial tensile strength)

Residual elongation (%) of 100 × (elongation after exposure)/(initial elongation)

(flame retardancy)

Flame retardancy was evaluated by a test according to UL 1581. Specifically, the vertical flame retardant test VW-1 defined in UL1581 was performed 3 times for the manufactured cable (length about 500mm), and the cable was determined as "pass" when all of the 3 times satisfied the criterion, and as "fail" when the criterion was not satisfied 1 time.

(Return to original)

The recoverability was evaluated by the following method. First, the outer skin layer collected from each cable was punched into a dumbbell shape to obtain a sample piece. Then, the test piece was elongated by 100% under the conditions of a reticle pitch of 25mm and a tensile speed of 200 mm/min using a tensile tester, and then the tester was stopped, and then the dumbbell was separated, and the amount of elongation (X value) at a reticle pitch of 25mm was measured after 10 seconds. Then, the restoration degree (Y) is calculated from the following equation. In this example, the Y value is set to 84 or more as pass, and less than 84 as fail. In addition, the degree of recovery Y is confirmed as an index of recovery since it shows a certain correlation with the repulsive elastic modulus.

Y＝-4＊X+200

(Cold resistance)

The cold resistance was evaluated by the following test. Specifically, a sample was collected by peeling off the outer skin layer from the produced cable, and a fracture test was performed on the sample using an embrittlement tester. In this example, the case where the sample did not fracture even at a temperature of-50 ℃ was defined as "pass", and the case where the sample fractured at a temperature of-50 ℃ or higher was defined as "fail".

< evaluation result >

The results of the evaluation of heat resistance, flame retardancy and restorability of the cable are summarized in tables 1 and 2.

In comparative examples 1 and 2, it was confirmed that since chlorinated polyethylene (a1) was not used, the restorability and cold resistance were reduced. In addition, in comparative example 3, it was confirmed that the flame retardancy was also lowered because the flame retardant (D) was not further used.

On the other hand, in examples 1 to 6, it was confirmed that heat resistance, flame retardancy, restorability and cold resistance can be obtained at a high level in a well-balanced manner. Specifically, it was confirmed that the chlorinated polyethylene (a1) having a chlorine content of 20% or more was blended so that the content ratio of the chlorinated polyethylene in the flame-retardant resin composition was in the range of 2% to 60%, thereby improving the properties.

In examples 7 to 17, it was confirmed that by using the chlorinated polyethylene (a1), the adipate TPU (a2), and the polyvinyl chloride resin (a3), the respective properties can be obtained more stably at a higher level than in example 1 and the like.

Furthermore, it was confirmed from examples 18 to 22 that even when the polyvinyl chloride resin (a3) is other than the ethylene-vinyl chloride copolymer, the ethylene-vinyl acetate copolymer, the styrene elastomer, the ethylene- α -olefin copolymer, the ethylene-acrylic acid ester copolymer, the acrylic resin, or a modified product thereof, various properties can be obtained at a high level and in a well-balanced manner in the same manner as the polyvinyl chloride resin (a 3).

As described above, if the above combination of the present invention is used as the base polymer (a), the plasticizer (B), the plasticizer (C), and the flame retardant (D), the outer skin layer can obtain heat resistance, flame retardancy, restorability, and cold resistance in a high level and well-balanced manner. The cable having such an outer sheath layer can be used as an FA robot cable.

< preferred mode of the invention >

Hereinafter, preferred embodiments of the present invention will be described.

[ additional notes 1]

One embodiment of the present invention relates to a cable including a conductor, an insulating layer covering a periphery of the conductor, and an outer sheath layer covering a periphery of the insulating layer,

the stabilizer (C) comprises hydrotalcite (C1) and metal soap (C2),

[ appendix 2]

In addition, according to supplementary note 1, it is preferable that the thermoplastic elastomer urethane (a2) is contained in the base polymer (a) in an amount of 6 to 620 parts by mass based on 100 parts by mass of the chlorinated polyethylene (a 1).

[ additional notes 3]

According to supplementary note 2, the content of the chlorinated polyethylene (a1) in the flame retardant resin composition is preferably 2% to 60%.

[ additional notes 4]

According to any one of supplementary notes 1 to 3, the content of the hydrotalcite (c1) is preferably 4 times or more the content of the metal soap (c2), and the content of the metal soap (c2) is preferably 1.6 parts by mass or less based on 100 parts by mass of the chlorinated polyethylene (a 1).

[ additional notes 5]

According to any one of supplementary notes 1 to 4, the content of the plasticizer (B) is preferably 2 to 60 parts by mass with respect to 100 parts by mass of the chlorinated polyethylene (a 1).

[ additional notes 6]

According to any one of supplementary notes 1 to 5, the content of the stabilizer (C) is preferably 2 to 20 parts by mass with respect to 100 parts by mass of the chlorinated polyethylene (a 1).

[ additional notes 7]

According to any one of supplementary notes 1 to 6, the content of the flame retardant (D) is preferably 1 to 70 parts by mass based on 100 parts by mass of the chlorinated polyethylene (a 1).

[ additional notes 8]

According to supplementary note 1, it is preferable that the base polymer (a) further contains a polyvinyl chloride resin (a3) and contains the thermoplastic polyurethane elastomer (a2) in an amount of 20 to 1700 parts by mass and the polyvinyl chloride resin (a3) in an amount of 3 to 900 parts by mass, based on 100 parts by mass of the chlorinated polyethylene (a 1).

[ appendix 9]

According to supplementary note 8, the content of the chlorinated polyethylene (a1) in the flame retardant resin composition is preferably 2% to 60%.

[ appendix 10]

According to supplementary note 8 or 9, it is preferable that the content of the hydrotalcite (c1) is 4 times or more the content of the metal soap (c2), and the content of the metal soap (c2) is 21 parts by mass or less with respect to 100 parts by mass of the chlorinated polyethylene (a 1).

[ appendix 11]

According to any one of supplementary notes 8 to 10, the content of the plasticizer (B) is preferably 2 to 600 parts by mass with respect to 100 parts by mass of the chlorinated polyethylene (a 1).

[ appendix 12]

According to any one of supplementary notes 8 to 11, the content of the stabilizer (C) is preferably 5 to 150 parts by mass with respect to 100 parts by mass of the chlorinated polyethylene (a 1).

[ additional notes 13]

According to any one of supplementary notes 8 to 12, the content of the flame retardant (D) is preferably 5 to 350 parts by mass based on 100 parts by mass of the chlorinated polyethylene (a 1).

[ appendix 14]

According to any one of supplementary notes 1 to 13, the chlorinated polyethylene (a1) preferably has a chlorine content of 20% or more.

[ appendix 15]

According to any one of supplementary notes 1 to 14, the thermoplastic polyurethane elastomer (a2) is preferably an adipate.

[ additional notes 16]

According to any one of supplementary notes 1 to 15, the plasticizer (B) preferably contains trimellitic ester.

[ additional character 17]

According to any one of supplementary notes 1 to 16, the thickness of the outer skin layer is preferably 0.1mm to 1.4 mm.

[ additional notes 18]

The polyvinyl chloride resin (a3) preferably has an average degree of polymerization of 1000 to 3800 according to any one of supplementary notes 1 to 17.

[ appendix 19]

The polyurethane thermoplastic elastomer (a2) preferably has a Shore A hardness of 80 to 95A according to any one of supplementary notes 1 to 18.

[ appendix 20]

Another aspect of the present invention relates to an electric wire including a conductor and an insulating layer covering a periphery of the conductor,

the stabilizer (C) comprises hydrotalcite (C1) and metal soap (C2),

Claims

1. A cable comprising a conductor, an insulating layer covering the periphery of the conductor, and an outer sheath layer covering the periphery of the insulating layer,

the outer skin layer is formed of a flame-retardant resin composition comprising a base polymer (A), a plasticizer (B), a stabilizer (C) and a flame retardant (D),

the base polymer (A) comprises chlorinated polyethylene (a1) and at least 1 polyurethane thermoplastic elastomer (a2) of adipate series, lactone series and carbonate series,

the stabilizer (C) comprises hydrotalcite (C1) and metal soap (C2),

2. The cable according to claim 1, wherein the base polymer (a) contains 6 to 620 parts by mass of the thermoplastic polyurethane elastomer (a2) per 100 parts by mass of the chlorinated polyethylene (a 1).

3. The cable according to claim 1, the base polymer (a) further comprising a polyvinyl chloride resin (a3), and comprising 20 parts by mass or more and 1700 parts by mass or less of the polyurethane thermoplastic elastomer (a2) and 3 parts by mass or more and 900 parts by mass or less of the polyvinyl chloride resin (a3) relative to 100 parts by mass of the chlorinated polyethylene (a 1).

4. The cable according to any one of claims 1 to 3, the polyurethane thermoplastic elastomer (a2) being an adipate ester system.

5. The cable according to any one of claims 1 to 4, the plasticizer (B) comprising trimellitic ester.

6. The cable according to any one of claims 1 to 5, wherein the chlorinated polyethylene (a1) has a chlorine content of 20% or more.

7. The cable according to any one of claims 1 to 6, wherein the outer sheath layer has a thickness of 0.1mm or more and 1.4mm or less.

8. An electric wire comprising a conductor and an insulating layer covering the periphery of 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 stabilizer (C) comprises hydrotalcite (C1) and metal soap (C2),