Cables and Wires

Abstract

To provide an electric wire and a cable which have flame retardancy, heat resistance, abrasion resistance and cold resistance in a balanced manner, significantly exhibit impact resistance and crush resistance, and suppress heat shrinkage due to molding strain after sheath extrusion.SOLUTION: A cable 1 includes an electric wire 10 where an insulating layer 12 is formed around a conductor 11, a shield layer 13 provided around the electric wire 10, and a skin layer 14 formed around the shield layer 13, wherein the skin layer 14 is composed of a flame-retardant resin composition containing a base polymer (A), a plasticizer (B), a stabilizer (C), and a flame retardant (D), and the base polymer (A) contains chlorinated polyethylene (a1) containing two or more kinds of chlorinated polyethylenes having different melt flow rates (MFR) by 10 times or more, a urethane thermoplastic elastomer (a2) containing at least one selected from an azipate-based urethane thermoplastic elastomer and a lactone-based urethane thermoplastic elastomer and / or polyvinyl chloride (a3).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to cables and wires. [Background technology]

[0002] A cable is constructed by providing an outer layer (so-called sheath) as a covering material around an insulated wire, which has an insulating layer provided around a conductor, for example. The outer layer is formed from a resin composition whose main raw materials are rubber and resin, and this resin composition is, for example, a soft vinyl chloride resin composition (soft PVC) blended with a flame retardant.

[0003] Furthermore, resin compositions are required to have different properties depending on the application of the cable. For example, cables for factory automation (FA) robots require flame retardancy, heat resistance, and abrasion resistance. In particular, in recent years, the FA robot industry has seen a demand for thinner cables and wires as robots become smaller. For example, when cables are made thinner, in addition to maintaining the aforementioned performance, additional tests are added, such as impact tests to confirm that the impact resistance is at or above the current level and crash resistance tests to confirm that the load value until the coating ruptures is at or above the current level.

[0004] When flexible PVC is used for the outer skin layer at a thinner thickness than in the past, the flame retardancy, heat resistance, and abrasion resistance decrease, and the added impact resistance and crush resistance also deteriorate. For this reason, the use of a resin composition in which flexible PVC is blended with an ether-based urethane thermoplastic elastomer (hereinafter simply referred to as "TPU") has been proposed (see, for example, Patent Document 1).

[0005] However, adding TPU to the outer layer often fails to achieve a good balance of flame retardancy, heat resistance, and abrasion resistance. Specifically, a large amount of flame retardant is sometimes added to the outer layer to achieve high flame retardancy. This large amount of flame retardant can cause the TPU hard segments to collapse, impairing the inherent heat resistance of the TPU. On the other hand, reducing the amount of flame retardant added to obtain the heat resistance of the TPU can sometimes result in the desired flame retardancy not being achieved. Furthermore, the heat resistance of ether-based TPU itself is insufficient, which often limits its range of use.

[0006] In addition, the outer layer may need to be cold-resistant, so that it maintains adequate elasticity even in low-temperature environments, but this is not always possible when TPU is added, such as when a carbonate type TPU is used.

[0007] To solve this problem, a kneading technique has been proposed that makes full use of the blending of adipate-type TPU with polyvinyl chloride (PVC), chlorinated polyethylene (CPE), and additives (see, for example, Patent Document 2). [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-91975 [Patent Document 2] Patent Publication No. 2021-86752 Summary of the Invention [Problem to be solved by the invention]

[0009] However, when a cable sheath material is extruded using the formulation of Patent Document 2, in addition to adjusting the temperature and drawing speed, it is sometimes necessary to suppress the draw ratio and evacuate the material during extrusion, which can lead to problems of reduced production efficiency. In addition, there are also cases where shrinkage occurs when the extruded sheath material is heated, which can be a problem.

[0010] Therefore, an object of the present invention is to provide an electric wire and cable that has a good balance of flame retardancy, heat resistance, abrasion resistance, and cold resistance in a cable, and that also exhibits significant impact resistance and crush resistance, and that suppresses heat shrinkage due to molding distortion after sheath extrusion. [Means for solving the problem]

[0011] A cable according to one embodiment of the present invention comprises a conductor, an insulating layer covering the conductor, and an outer jacket layer covering the insulating layer, wherein the outer jacket layer is made of a flame-retardant resin composition containing a base polymer (A), a plasticizer (B), a stabilizer (C), and a flame retardant (D), wherein the base polymer (A) comprises chlorinated polyethylene (a1) containing two or more types of chlorinated polyethylene having melt flow rates (MFR) that differ by 10 times or more, and a urethane thermoplastic elastomer (a2) and / or polyvinyl chloride (a3) ​​containing at least one selected from adipate-based and lactone-based elastomers, the stabilizer (C) comprises hydrotalcite (c1) and a metal soap (c2), and the flame retardant (D) comprises at least one selected from a metal hydroxide (d1), a brominated flame retardant (d2), amorphous silica (d3), and antimony trioxide (d4).

[0012] An electric wire according to one embodiment of the present invention includes a conductor and an insulating layer covering the conductor, wherein the insulating layer is made 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) includes chlorinated polyethylene (a1) containing two or more types of chlorinated polyethylene having melt flow rates (MFR) that differ by 10 times or more, and a urethane thermoplastic elastomer (a2) and / or polyvinyl chloride (a3) ​​containing at least one selected from adipate-based and lactone-based elastomers. The stabilizer (C) includes hydrotalcite (c1) and a metal soap (c2). The flame retardant (D) includes at least one selected from metal hydroxide (d1), brominated flame retardant (d2), amorphous silica (d3), and antimony trioxide (d4). [Effects of the Invention]

[0013] According to this embodiment, the cable can achieve a good balance of flame retardancy, heat resistance, resilience, and cold resistance, and also exhibit impact resistance and crush resistance, and can suppress heat shrinkage due to molding distortion after sheath extrusion. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a cross-sectional view perpendicular to the length direction of a cable according to the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0015] <Findings of the Inventors> We have investigated the types and formulations of various additives to improve the affinity of high molecular weight CPE (low MFR CPE) with soft PVC, which has low heat shrinkage, without reducing the resilience when used as chlorinated polyethylene (CPE), to improve the affinity of these with TPU, and to improve the affinity of CPE with TPU in systems where polyvinyl chloride (PVC) is not used.

[0016] As a result, it was found that the above problems could be solved by blending a low-molecular-weight CPE (high-MFR CPE) with the conventionally used low-MFR CPE. Furthermore, the results of this study indicated that the high-MFR CPE should preferably have an MFR 10 times or more that of the low-MFR CPE, and that the difference between the maximum and minimum chlorine amounts of the two CPEs should preferably be within 20% by mass.

[0017] We also confirmed that this type of blending facilitates selective dispersion of stabilizers and flame retardants in plasticized flexible PVC and CPE. Hydrotalcite and metal soaps are good stabilizers, while at least one of metal hydroxides, brominated flame retardants, amorphous silica, and antimony trioxide is good flame retardants.

[0018] Furthermore, in order to improve the heat resistance of the resin composition discovered this time, TPUs were also investigated, and it was found that among TPUs, adipate-based TPUs were the best. Generally, TPUs are obtained by the reaction of polyols, diols, and isocyanates, and have rigid hard segments and flexible soft segments. TPUs include polyester-based TPUs, which use polyester polyols, and polyether-based TPUs, which use polyether polyols. It was found that polyester-based TPUs were desirable from the standpoint of heat resistance in the resin composition discovered this time. While there are various types of polyester-based TPUs depending on the type of polyester polyol, it was also found that adipate-based and lactone-based TPUs were desirable from the standpoint of various properties.

[0019] This combination of materials allows additives such as stabilizers and flame retardants to be selectively dispersed in the plasticized flexible PVC and CPE. This allows for the properties of both the CPE and TPU to be utilized while suppressing the loss of heat resistance that would otherwise occur with the incorporation of large amounts of additives and further improving cold resistance. As a result, a good balance of flame retardancy, heat resistance, abrasion resistance, and cold resistance can be achieved, and the heat shrinkage rate of the molded product can also be reduced.

[0020] Furthermore, the newly discovered resin composition was found to exhibit not only the above-mentioned properties but also high impact resistance and crush resistance compared to currently used flexible PVC-based materials. This could potentially be a technology that enables the aforementioned problem of reducing the diameter of cables. Specifically, by using the newly discovered resin composition, it is expected that the sheath performance of a currently used flexible PVC sheath with a thickness of 0.81 mm can be reduced to, for example, 0.41 mm, and still achieve the same or better performance. The present invention has been made based on the above findings.

[0021] First Embodiment An electric wire and cable according to an embodiment of the present invention will be described in detail below with reference to the drawings. Fig. 1 is a cross-sectional view perpendicular to the length of a cable according to this embodiment. In this specification, a numerical range expressed using "to" means a range that includes the numerical values ​​before and after "to" as the lower and upper limits.

[0022] [Flame-retardant resin composition] First, in this embodiment, a flame-retardant resin composition suitable for forming the outer sheath layer of a cable will be described. The flame-retardant resin composition used in this embodiment contains a base polymer (A), a plasticizer (B), a stabilizer (C), and a flame retardant (D), and may contain other additives as needed.

[0023] Each component contained in the flame-retardant resin composition will be described in detail below.

[0024] [Base polymer (A)] In this embodiment, a predetermined chlorinated polyethylene (a1) and at least one of an adipate-based or lactone-based urethane thermoplastic elastomer (a2) and / or polyvinyl chloride (a3) ​​are used as the base polymer (A).

[0025] The chlorinated polyethylene (a1) (hereinafter sometimes referred to as "CPE (a1)") used in this embodiment is a component that contributes to improving the flame retardancy and cold resistance of the coating layer and also suppresses heat shrinkage. Chlorinated polyethylene (a1) is obtained by blowing chlorine gas into an aqueous suspension in which raw material polyethylene is suspended and dispersed in water.

[0026] In this embodiment, CPE (a1) is characterized in that it is a combination of two or more CPEs with different metror flow rates (MFR), i.e., a high molecular weight chlorinated polyethylene (low MFR CPE) and a low molecular weight chlorinated polyethylene (high MFR CPE). In this case, it is preferable to use a combination of CPEs with metror flow rates (MFR) that differ by 10 times or more.

[0027] In this embodiment, it is preferable to use a low-MFR chlorinated polyethylene having an MFR of less than 4 g / 10 min as the low-MFR CPE, and a high-MFR chlorinated polyethylene having an MFR of 4 g / 10 min or more as the high-MFR CPE, where the MFR value is a value measured under conditions of 180°C and 21.6 kg according to JIS K 7112.

[0028] Furthermore, when the amount of low MFR CPE added is A and the amount of high MFR CPE added is B, it is preferable that the ratio [addition amount A to addition amount B (A / B)] is 0.5 or more and 20 or less, since this acts to further effectively suppress heat shrinkage.

[0029] The amount of chlorine contained in the chlorinated polyethylene (a1) is not particularly limited, but from the viewpoint of improving cold resistance and flame retardancy, it is preferably 20% by mass or more, more preferably 20 to 45% by mass. This CPE (a1) may be a combination of multiple CPEs with different chlorine amounts.

[0030] When CPEs with different chlorine contents are used in combination, it is preferable from the viewpoint of mutual compatibility that the difference between the maximum and minimum chlorine contents of the multiple CPEs used is within 20 mass %.

[0031] The urethane thermoplastic elastomer (a2) (hereinafter, sometimes referred to as "TPU (a2)") used in this embodiment is a component that mainly imparts restoring properties to the covering layer.

[0032] The urethane thermoplastic elastomer (a2) used in this embodiment is a component containing at least one selected from adipate-based and lactone-based elastomers. The adipate-based elastomer is a urethane thermoplastic elastomer (TPU) obtained by reacting an adipic acid-based polyester polyol with a diol and an isocyanate. The lactone-based elastomer is, for example, a caprolactone-based polyester polyol with a diol and an isocyanate.

[0033] To achieve even higher levels of hydrolysis resistance, heat resistance, and cold resistance, it may be effective to mix an ether-based TPU, which has excellent cold resistance, heat resistance, and hydrolysis resistance, with a carbonate-based TPU, which has excellent heat resistance, in any ratio. However, this will increase material costs.

[0034] As the diol, which is a raw material for TPU, known components can be used, and examples thereof 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, 3,3,5-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, dimer diol, and hydrogenated dimer diol.

[0035] Known isocyanates, which are raw materials for TPU, can be used, including aliphatic diisocyanates such as hexamethylene diisocyanate, butane-1,4-diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, xylylene diisocyanate, and m-tetramethylxylylene diisocyanate. Alicyclic diisocyanates include isophorone diisocyanate, cyclohexane-1,4-diisocyanate, lysine diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, methylcyclohexane diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, isopropylidenedicyclohexyl-4,4'-diisocyanate, and norbornane diisocyanate. Further examples include aromatic diisocyanates such as 1,5-naphthylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-diphenyldimethylmethane diisocyanate, 4,4'-dibenzyl diisocyanate, dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, tolylene diisocyanate, and tetramethylxylylene diisocyanate.

[0036] The TPU (a2) is not particularly limited as long as it is an adipate-based or lactone-based TPU from the viewpoint of heat resistance in the coating layer, but an adipate-based TPU is preferred from the viewpoint of adjusting the hardness in the coating layer.

[0037] Adipate-based TPUs are advantageous not only for adjusting hardness, but also for their superior affinity with PVC (a3) ​​and CPE (a1), which will be described later, compared to lactone-based TPUs, making it easier to form the phase structure described later in the coating layer that makes up the cable's outer sheath, and for achieving various properties more stably. This is because adipate-based TPUs have a structure derived from adipic acid, and even when additives are added, the bonding strength of the hydrogen bonds and urethane bonds in the hard segments is not significantly impaired, making it easier to maintain various properties at a high level.

[0038] The hardness of the adipate-based TPU (a2) is not particularly limited, but from the viewpoint of the balance between the restoring property and heat resistance of the coating layer, the hardness is preferably 80A to 95A in Shore A hardness, and more preferably 80A to 90A.

[0039] The polyvinyl chloride (a3) ​​(hereinafter sometimes referred to as "PVC (a3)") used in this embodiment may be a homopolymer of vinyl chloride, or a copolymer of vinyl chloride with other copolymerizable monomers. Examples of copolymers that may be used include copolymers of vinyl chloride with ethylene or vinyl acetate. Partially crosslinked PVCs may also be used.

[0040] The K value of the polyvinyl chloride (a3) ​​is preferably 65.7 to 94.9, and more preferably 71 to 85.6. By setting the K value to 65.7 or more, the coating layer can be provided with high heat resistance, flame retardancy, abrasion resistance, impact resistance, and crush resistance, and also has excellent affinity with the (a1) and (a2) components. On the other hand, if the average polymerization degree is excessively high, the molding processability of the flame-retardant resin composition may be reduced. However, by setting the K value to 94.9 or less, the performance of the coating layer can be maintained at a high level without impairing the molding processability. Note that multiple polyvinyl chlorides (a3) ​​with different average polymerization degrees may be used in combination.

[0041] In addition to the components (a1), (a2), and (a3), other polymer components may be appropriately blended into the base polymer (A) within the range that does not impair the desired properties. Examples of other polymer components that can be used include ethylene-vinyl acetate copolymers, styrene-based elastomers, ethylene-α-olefin copolymers, ethylene-acrylic acid ester copolymers, acrylic resins, and modified versions of these.

[0042] When other polymer components are blended, the amount of the other polymer components is preferably 40% by mass or less, more preferably 20% by mass or less, based on 100% by mass of the base polymer (A).

[0043] [Plasticizer (B)] The plasticizer (B) is a component that imparts flexibility to the coating layer. Any known plasticizer blended in this type of resin composition can be used as the plasticizer (B). Examples of such plasticizers include trimellitic esters, phthalic esters, and adipate polyesters. Among these, trimellitic esters are preferred because they do not impair the properties of the cable's outer sheath when applied to the cable.

[0044] Trimellitic esters can maintain higher heat resistance of the coating layer than phthalic esters. Furthermore, they are less sticky than adipate polyesters, which improves the handleability of the coating layer when applied to the outer sheath of a cable. Trimellitic esters can be used alone or in combination with other plasticizers, such as adipate polyesters, as long as the desired properties are not impaired.

[0045] As the trimellitic acid ester, for example, tri-2-ethylhexyl trimellitate, tri-n-octyl trimellitate, mixed alkyl trimellitate, triisononyl trimellitate, etc. can be used, and an antioxidant mixed type may also be used. In this case, a phenolic antioxidant is generally used, and those added in an amount of 0.1 to 1 mass % to the trimellitic acid ester are commercially available.

[0046] [Stabilizer (C)] The stabilizer (C) acts as a heat stabilizer that suppresses the deterioration of the CPE (a1) and PVC (a3) ​​when preparing the flame-retardant resin composition, and is also a component that stabilizes the phase structure of the flame-retardant resin composition.

[0047] In this embodiment, from the viewpoint of selectively dispersing CPE (a1) or a system using CPE (a1) and PVC (a3) ​​in combination, hydrotalcite (c1) and metal soap (c2) are used as the stabilizer (C). There are no particular limitations on the hydrotalcite (c1) and metal soap (c2) as long as they have excellent compatibility with CPE (a1) and PVC (a3), and known components can be used.

[0048] Hydrotalcite (c1) is a magnesium and aluminum-based layered compound, and among these, MgO / Al2O3 = 2.1 to 4.5 is preferred.

[0049] Examples of the metal soap (c2) include metal soaps made of a fatty acid such as stearic acid, lauric acid, or octylic acid and a metal such as calcium or zinc.

[0050] The stabilizer (C) may contain a stabilizing aid as a component other than those described above. The presence or absence of the stabilizing aid has no effect on the TPU (a2), and it acts only on the PVC (a3). Examples of stabilizing aids that can be used, as needed, include dibenzoylmethane, stearylbenzoylmethane and their metal salts, polyhydric alcohols, trihydroxyethyl isocyanate, silica, calcium carbonate, antioxidants, talc, clay, and the like.

[0051] [Flame retardant (D)] The flame retardant (D) is a component that imparts flame retardancy to the coating layer. In this embodiment, from the viewpoint of selectively dispersing the flame retardant additive in the CPE (a1) or in a system containing the CPE (a1) and the PVC (a3), at least one of metal hydroxides (d1), brominated flame retardants (d2), amorphous silica (d3), and antimony trioxide (d4) is used as the flame retardant (D). It is preferable to select a flame retardant that does not show obvious alkaline coloration with phenolphthalein after immersion in a 40% by mass aqueous solution of ethanol for three days.

[0052] The metal hydroxide (d1) can be any metal hydroxide known as a flame retardant, and is not particularly limited, but for example, magnesium hydroxide, aluminum hydroxide, etc. Among these, aluminum hydroxide is particularly preferred in view of the results of the above-mentioned alkali coloration test.

[0053] Even with surface-treated grades, magnesium hydroxide exhibits color change in phenolphthalein solution after three days of immersion, suggesting that the urethane bonding, hydrogen bonding, and ester bonding strength in the TPU hard segments may weaken over time. This morphological change may impair the heat resistance of TPU. In this regard, aluminum hydroxide is preferable because it exhibits weak color change and maintains high heat resistance.

[0054] The metal hydroxide (d1) may not be surface-treated, or may be surface-treated with silane or fatty acid. 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 preferably, for example, 0.2 μm.

[0055] It is also possible to replace the amount of aluminum hydroxide with magnesium hydroxide to such an extent that the coloring of phenolphthalein can be suppressed.

[0056] As the brominated flame retardant (d2), for example, decabromodiphenyl ether, decabromodiphenyl ethane, etc. 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 preferably, for example, 2 μm.

[0057] From the viewpoint of dispersibility, the amorphous silica (d3) preferably has an average particle size of 5 μm or less. There is no particular lower limit, but it is preferably, for example, 0.01 μm.

[0058] Antimony trioxide (d4) is a compound known as a flame retardant. From the viewpoint of dispersibility, it is preferable that the average particle size of this antimony trioxide (d4) is 5 μm or less. The lower limit is not particularly limited, but for example, 0.5 μm is preferable.

[0059] (Other additives) The flame-retardant resin composition used in the present embodiment may contain other additives, if necessary, in addition to the above components (A) to (D). Examples of such additives include crosslinking aids, antioxidants (thermal aging inhibitors), copper inhibitors, lubricants, and processing aids.

[0060] Examples of crosslinking aids include trimethylolpropane trimethacrylate (TMPT), triallyl isocyanurate, triallyl cyanurate, N,N'-metaphenylene bismaleimide, ethylene glycol dimethacrylate, zinc acrylate, zinc methacrylate, etc. When this flame-retardant resin composition is used without crosslinking using electron beam crosslinking or the like, it is not necessary to add a crosslinking aid.

[0061] Examples of antioxidants include phenol-based antioxidants, phosphorus-based antioxidants, sulfur-based antioxidants, etc. Examples of copper inhibitors include N-(2H-1,2,4-triazol-5-yl)salicylamide, dodecanedioic acid bis[N2-(2-hydroxybenzoyl)hydrazide], 2',3-bis[[3-[3,5-di-tert-butyl-4-hydroxyphenyl]propionyl]]propionohydrazide, etc., and more preferably 2',3-bis[[3-[3,5-di-tert-butyl-4-hydroxyphenyl]propionyl]]propionohydrazide.

[0062] Examples of lubricants include hydrocarbon-based, fatty acid-based, fatty acid amide-based, ester-based, and alcohol-based lubricants.

[0063] Examples of processing aids include fatty acids such as ricinoleic acid, stearic acid, palmitic acid, and lauric acid, as well as salts and esters of these acids, and polymethyl methacrylate.

[0064] (phase structure) In the flame-retardant resin composition used in this embodiment, the base polymer components, chlorinated polyethylene (a1), urethane thermoplastic elastomer (a2), and polyvinyl chloride (a3), are compatible with CPE (a1) and PVC (a3), while the TPU (a2) component forms a phase-separated sea-island structure or spinodal dispersion with them. Furthermore, the stabilizer (C) and flame retardant (D) are more likely to selectively disperse in the phase containing CPE (a1) and PVC (a3) ​​than in TPU (a2). Therefore, when using TPU (a2), the amount of additive components that penetrate into TPU (a2) can be reduced compared to conventional methods, suppressing a decrease in the urethane bonding strength and hydrogen bonding strength of the TPU (a2). This allows the inherent properties of the TPU (a2) component to be maintained at a high level.

[0065] (Content ratio) The content ratio of each component in the resin composition described above is as follows: The base polymer (A) is contained in an amount of preferably 50 to 95% by mass, and more preferably 65 to 90% by mass, based on 100% by mass of the resin composition.

[0066] When CPE (a1), TPU (a2) and PVC (a3) ​​are used as the base polymer (A), the content ratios thereof are preferably as follows.

[0067] The base polymer (A) preferably contains 4 to 800 parts by mass of the TPU (a2) when the total content of the CPE (a1) and the PVC (a3) ​​is 100 parts by mass. By mixing them in such a ratio, the above-mentioned phase structure is easily formed, and the desired properties are easily obtained.

[0068] When the base polymer contains 100 parts by mass of CPE (a1), any plasticizer can be added so that the hardness falls within the range described above for the three-component composition of CPE (a1), TPU (a2), and PVC (a3).

[0069] In this case, the content of TPU (a2) is preferably 5% by mass or more and 85% by mass or less of the total amount of component (A). By adjusting the content within such a ratio, it becomes possible to obtain a high level of well-balanced properties in the coating layer.

[0070] The content of the plasticizer (B) is not particularly limited, but if it is too small, when CPE (a1), PVC (a3), and TPU (a2) are mixed, not only will the cold resistance be reduced and a good balance of various properties be lost, but the flexibility of the cable will also be impaired. Furthermore, if it is too high, the adhesiveness of the coating layer will increase, which may result in a decrease in moldability and flame retardancy. From the viewpoint of achieving a high level of a good balance of various properties in the coating layer, the content of the plasticizer (B) is preferably 5 to 50 parts by mass, based on 100 parts by mass of the total content of CPE (a1) and PVC (a3).

[0071] The content of the stabilizer (C) is not particularly limited, but the metal soap (c2) is more likely to reduce the hydrogen bonding strength and urethane bonding strength in the hard segments of the TPU (a2) than the hydrotalcite (c1), which may impair the heat resistance of the coating layer. Therefore, from the viewpoint of stabilizing the CPE (a1) and the PVC (a3) ​​while maintaining high heat resistance, it is preferable to reduce the content of the metal soap (c2) and increase the content of the hydrotalcite (c1) to ensure the effect of the stabilizer (C). Specifically, it is preferable that the content of the metal soap (c2) be 3 parts by mass or less (e.g., 0.1 to 3 parts by mass) per 100 parts by mass of the total amount of the CPE (a1) and the PVC (a3), and that the content of the hydrotalcite (c1) be 1.5 times or more the content of the metal soap (c2).

[0072] The lower limit of the content of the metal soap (c2) is not particularly limited, but if it is too low, the flame-retardant resin composition may become discolored or its properties may deteriorate, so it is preferably 0.01 parts by mass or more. The content of the hydrotalcite (c1) is not particularly limited, but it is preferably 1.5 to 15 parts by mass per 100 parts by mass of the total amount of the CPE (a1) and the PVC (a3). The total content of the stabilizer (C) is preferably 2 to 20 parts by mass.

[0073] The content of the flame retardant (D) is not particularly limited, but the total content of components (d1) to (d4) is preferably 1 to 200 parts by mass per 100 parts by mass of the total of CPE (a1) and PVC (a3). The content of each of components (d1) to (d4) is not particularly limited as long as the total amount falls within the above range, but it is preferred that each be in the following range: 0 to 60 parts by mass for component (d1), 0 to 60 parts by mass for component (d2), 0 to 30 parts by mass for component (d3), and 0 to 60 parts by mass for component (d4).

[0074] (Preparation of Flame-Retardant Resin Composition) The flame-retardant resin composition can be prepared by mixing the above components (A) to (D) and, if necessary, other additives, and melt-kneading the mixture. Kneading can be carried out using a known kneading device, for example, a batch kneader such as a Banbury mixer or a pressure kneader, or a continuous kneader such as a twin-screw extruder.

[0075] Specifically, one example is a method in which chlorinated polyethylene (a1), polyvinyl chloride (a3), plasticizer (B), stabilizer (C), and flame retardant (D) are first mixed together to obtain a chlorine-based flame-retardant resin composition, and then the urethane thermoplastic elastomer (a2) is added and melt-kneaded. A similar melt-kneading method can be used even when polyvinyl chloride (a3) ​​is not added. This allows the TPU (a2) to be dispersed in the chlorine-based flame-retardant resin composition, forming a flame-retardant resin composition.

[0076] As described above, in the flame-retardant resin composition, it is not necessary to pelletize the chlorine-based flame-retardant resin composition beforehand; pellets of TPU (a2) can be added to the molten resin and kneaded. This kneading procedure can reduce the intrusion of additives into the TPU (a2) phase. This makes it possible to maintain higher heat resistance in the coating layer, making it suitable for use as, for example, the outer sheath layer of a cable.

[0077] When using PVC (a3), it is even better to mix the plasticizer (B) and additives until they are compatible and then dry up before adding and mixing the CPE (a1), as this will maintain the powder form. If the powder state can be maintained, it can be easily mixed with TPU (a2) pellets, and for example, material can be fed using a screw feeder used in a twin-screw extruder. This means that the options for kneading and molding machines are expanded.

[0078] The flame-retardant resin composition serving as the intermediate material can also be obtained by first granulating (pelletizing) the chlorine-containing flame-retardant resin composition and then mixing and kneading or extrusion molding it with TPU (a2). This method is effective when it is desired to quickly produce multiple types of chlorine-containing flame-retardant resin compositions with different hardness, abrasion resistance, and flame retardancy.

[0079] [cable] Next, a cable according to one embodiment of the present invention will be described with reference to Fig. 1. Fig. 1 is a cross-sectional view perpendicular to the length direction of the cable according to this embodiment.

[0080] As shown in FIG. 1, the cable 1 of this embodiment is configured to include an electric wire 10 having an insulating layer 12 formed around a conductor 11, a shielding layer 13 provided around the electric wire 10, and an outer layer 14 (sheath 14) formed around the shielding layer 13.

[0081] (conductor) The conductor 11 can be any metal wire commonly used for electric wires, such as copper wire or copper alloy wire, as well as aluminum wire, gold wire, silver wire, etc., without any particular limitation. The conductor 11 may also be a metal wire plated with metal such as tin or nickel. Furthermore, the conductor 11 can also be a twisted wire made by twisting metal wires together.

[0082] (insulating layer) The insulating layer 12 is a covering layer made of an insulating material and provided around the conductor 11. The insulating layer 12 can be formed from a conventionally known material, such as a polymer such as a fluororesin, a polyester resin, or high-density polyethylene, or a composition in which a flame retardant, an antioxidant, or the like is added to a polymer, or it may be formed from the flame-retardant resin composition described above. The thickness of the insulating layer 12 is not particularly limited, and is preferably 0.1 mm to 1.5 mm, for example.

[0083] (shield layer) The shield layer 13 is a covering layer having an electromagnetic shielding effect that is provided around the twisted wire formed by twisting together a plurality of electric wires 10. Any known shield layer can be used as the shield layer 13 without any particular restrictions, and is formed, for example, by a braided structure in which a plurality of metal wires such as annealed copper wires are braided.

[0084] (outer skin layer) The outer jacket layer 14 is a covering layer provided around the shielding layer 13 and forms the outermost layer of the cable 1. In this embodiment, the outer jacket layer 14 is formed from the flame-retardant resin composition described above. The thickness of the outer jacket layer 14 is not particularly limited, but is preferably 0.1 mm to 1.4 mm from the viewpoint of obtaining a high level of various properties in a well-balanced manner.

[0085] The flame-retardant resin composition may be crosslinked to improve the oil resistance and flame-extinguishing stability of the outer skin layer 14. The crosslinking method is not particularly limited, and for example, electron beam crosslinking can be used. When electron beam crosslinking is performed, the extrusion-molded flame-retardant resin composition may be crosslinked by irradiating it with an electron beam of 0.5 to 30 Mrad.

[0086] (Cable manufacturing method) First, a conductor 11 is prepared, and the flame-retardant resin composition of the present embodiment described above is extruded using an extrusion molding machine so as to cover the conductor 11, forming an insulating layer 12 of a predetermined thickness, thereby obtaining an electric wire 10. Next, a plurality of electric wires 10 are twisted together, and a shielding layer 13 is formed around them using a braiding machine.

[0087] Next, the flame-retardant resin composition of the present embodiment described above is extruded using an extrusion molding machine so as to cover the periphery of the shielding layer 13, thereby forming the outer cover layer 14 of a predetermined thickness. In this way, the cable 1 of the present embodiment can be manufactured.

[0088] <Effects of this embodiment> According to this embodiment, one or more of the following effects can be achieved.

[0089] According to the cable 1 of this embodiment, the flame-retardant resin composition forming the outer sheath layer 14 uses, as the base polymer (A), a chlorinated polyethylene (a1) containing two or more chlorinated polyethylenes with different MFRs and polyvinyl chloride (a3), or a chlorinated polyethylene (a1) containing two or more chlorinated polyethylenes with different MFRs and a urethane thermoplastic elastomer (a2) containing at least one of an adipate-based and a lactone-based elastomer, and contains, as the stabilizer (C), hydrotalcite (c1) and a metal soap (c2), and, as the flame retardant (D), at least one of a metal hydroxide (d1), a bromine-based flame retardant (d2), amorphous silica (d3), and antimony trioxide (d4).

[0090] Components (C) and (D) are more selectively dispersible in CPE (a1) and PVC (a3) ​​or CPE (a1) than in TPU (a2), which reduces the penetration of additives into TPU (a2), thereby preventing a decrease in urethane bonding strength and hydrogen bonding strength in component (a2) due to the penetration of additives.

[0091] As a result, while obtaining the abrasion resistance provided by the TPU (a2), it is possible to maintain high properties such as heat resistance of the outer skin layer 14. Furthermore, since at least one of an adipate-based TPU (a2) and a lactone-based TPU (a2) is used as the TPU (a2), it is possible to maintain high heat resistance of the outer skin layer 14.

[0092] Furthermore, the combination of the plasticizer (B) and stabilizer (C) allows the inherent properties of the CPE (a1) and TPU (a2) to be maintained at a high level without significantly impairing them. Furthermore, the flame retardant (D) improves the flame retardancy of the outer jacket layer 14. Therefore, the cable 1 of this embodiment can achieve a good balance of recovery, heat resistance, flame retardancy, and cold resistance.

[0093] Furthermore, since the composition maintains the performance of TPU (a2), it is also possible to achieve impact resistance and crash resistance.

[0094] Specifically, the cable 1 of this embodiment has high flame retardancy, passing the vertical flame retardancy test VW-1 specified in the flame retardancy standard UL1581. It also has high heat resistance, meeting the 105°C rating of the UL standard. It also has high abrasion resistance, preventing rupture of the coating when used as a cable for factory automation robots. Furthermore, it has high cold resistance, preventing breakage even at -50°C when subjected to the embrittlement test described below.

[0095] Furthermore, since the cable can exhibit impact resistance, crush resistance, and abrasion resistance, it can be made thinner than the cable sheaths made of polyvinyl chloride compositions that have been used conventionally.

[0096] Although the present embodiment has been described focusing on the case where the flame-retardant resin composition is used for the outer sheath layer of a cable, the present invention is not limited thereto. The flame-retardant resin composition of the present embodiment can also be used for the insulating layer of an electric wire, for example. [Example]

[0097] Next, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

[0098] <Material> In this example, the materials used to prepare the flame-retardant resin composition for forming the outer skin layer are as follows.

[0099] [(A) Base polymer] The following was used as the chlorinated polyethylene (a1).

[0100] <Low MFR chlorinated polyethylene (a1-1)> (a1-1a) Chlorinated polyethylene 1 (product name "ELASLENE 352GB", manufactured by Showa Denko K.K., chlorine content: 34 to 37 mass%, crystalline content: 20 J / g, MFR: 1.6) (a1-1b) Chlorinated polyethylene 2 (product name "ELASLENE 301A", manufactured by Showa Denko K.K., chlorine content: 30 to 33 mass%, crystalline content: <2 J / g, MFR: 1.6) (a1-1c) Chlorinated polyethylene 3 (product name "Elaslen 401A", manufactured by Showa Denko K.K., chlorine content: 38 to 41 mass%, crystalline content: <2 J / g, MFR: 1.6)

[0101] <High MFR chlorinated polyethylene (a1-2)> (a1-2a) Chlorinated polyethylene 4 (product name "Elaslen 303JB", manufactured by Showa Denko K.K., chlorine content: 30 to 33 mass%, crystalline content: 29 J / g, MFR: 25) (a1-2b) Chlorinated polyethylene 5 (product name "ELASLENE 404FB", manufactured by Showa Denko K.K., chlorine content: 38 to 41% by mass, crystalline content: 50 J / g, MFR: 25) (a1-2c) Chlorinated polyethylene 6 (product name "Elaslen 353A", manufactured by Showa Denko K.K., chlorine content: 33.5 to 36% by mass, MFR: 65) (a1-2d) Chlorinated polyethylene 7 (product name "Elaslen 454A", manufactured by Showa Denko K.K., chlorine content: 43 to 46% by mass, MFR: 70)

[0102] The following was used as the urethane thermoplastic elastomer (a2). (a2-1) Adipate type TPU (product name "P25MRWJE", manufactured by Nihon Miractoran Co., Ltd., Shore A hardness 90) (a2-2) Caprolactone type TPU (product name "E585", manufactured by Nihon Miractoran Co., Ltd., Shore A hardness 85)

[0103] The following was used as polyvinyl chloride (a3): (a3-1) Polyvinyl chloride 1 (product name "TH-1000", manufactured by Taiyo PVC Co., Ltd., K value 65.7 to 67.7 (a3-2) Polyvinyl chloride 2 (product name "TH-1300", manufactured by Taiyo PVC Co., Ltd., K value 71.0 to 72.6 (a3-3) Polyvinyl chloride 3 (product name "TH-1700", manufactured by Taiyo PVC Co., Ltd., K value 75.7 to 78.1 (a3-4) Polyvinyl chloride 4 (product name "TH-2500", manufactured by Taiyo PVC Co., Ltd., K value 84-85.6)

[0104] [Plasticizer (B)] The following was used as the plasticizer (B): (b1) Di-2-ethylhexyl trimellitate (TOTM) (product name "T08", manufactured by Kao Corporation) (b2) Dioctyl trimellitate (n-TOTM) (product name "N08", manufactured by Kao Corporation) (b3) Adipic acid polyester (product name "P1030", manufactured by ADEKA Corporation)

[0105] [Stabilizer (C)] The following was used as the hydrotalcite (c1) of the stabilizer (C). (c1) Hydrotalcite (product name "HT-1", manufactured by Sakai Chemical Industry Co., Ltd.) The following was used as the metal soap (c2) of the stabilizer (C). (c2-1) Zinc stearate (product name "SZ-P", manufactured by Sakai Chemical Industry Co., Ltd.) (c2-2) Calcium stearate (product name "SC-P", manufactured by Sakai Chemical Industry Co., Ltd.) The following were used as other components of the stabilizer (C). (c3) Stabilizing agents (including β-diketones, etc.)

[0106] [Flame retardant (D)] The following metal hydroxides (d1) were used as the flame retardant (D). (d1) Untreated aluminum hydroxide (product name "BF013", manufactured by Nippon Light Metal Co., Ltd.) The following was used as the brominated flame retardant (d2) of the flame retardant (D). (d2) Brominated flame retardant 1 (decabromodiphenylethane, product name "Scitex 8010", manufactured by Almavale Co., Ltd., average particle size 5.6 μm) The following was used as amorphous silica (d3) of the flame retardant (D).

[0107] (d3) Amorphous silica (product name "SIDISTAR120U", manufactured by Elkem Co., Ltd., average particle size 0.15 μm) The following was used as the flame retardant (D), antimony trioxide (d4): (d4) Antimony trioxide (product name "NANO200", manufactured by Changde Chenzhou Co., Ltd., average particle size 0.8 μm)

[0108] [Additive (E)] The following additives (E) were used: (e1) Crosslinking coagent (trimethylolpropane trimethacrylate, product name "TMPT", manufactured by Shin-Nakamura Chemical Co., Ltd.) (e2) Calcined clay (product name "SP#33", manufactured by BASF) (e3) Black colorant (product name "NBP2425", manufactured by Nikko Bix Co., Ltd.) (e4) White colorant (product name: "Titanium White R820", manufactured by Ishihara Sangyo Kaisha, Ltd.) (e5) Calcium carbonate (product name "Softon 1500", manufactured by Bihoku Funka Kogyo Co., Ltd.)

[0109] 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 were prepared. The conductor used was a 28AWG (19 / 0.08) tin-plated copper wire conductor. The resin composition used for forming the insulating layer was a composition containing ETFE (tetrafluoroethylene-ethylene copolymer), a fluororesin.

[0110] The flame-retardant resin composition for forming the outer skin layer was prepared by mixing and kneading the above-mentioned materials to obtain the composition shown in Example 1 of Table 1. The flame-retardant resin composition was prepared by melt-kneading the mixture at a discharge temperature of 165°C using a pressure kneader, cutting the mixture into strands, and then drying the mixture at 80°C for 2 hours.

[0111] Next, using a 40 mm extruder for electric wire manufacturing, a resin composition for forming an insulating layer was extruded around the conductor to form an insulating layer with a thickness of 0.2 mm. This resulted in an electric wire. Five two-pair electric wires were then twisted together, and a braiding machine was used to twist staple yarn and polyester tape (1 / 4 wrap) around them (right twist) to form a shielding layer. Next, using a 65 mm single-screw extruder for electric wire manufacturing, a flame-retardant resin composition was extruded around the shielding layer by a tube extrusion method to form the cable structure shown in Figure 1, and an outer jacket layer with the thickness shown in Table 2 was formed. This resulted in the production of the cable of Example 1.

[0112] <Examples 2 to 10> In Examples 2 to 10, 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.

[0113] <Comparative Examples 1 to 4> In Comparative Examples 1 to 4, cables were produced in the same manner as in Example 1, except that the resin compositions and sheath thicknesses shown in Tables 3 and 4 were used.

[0114] In the above Examples 1 to 10 and Comparative Examples 1 to 4, specific compositional information in the resin compositions was calculated for the following items and is summarized in Tables 2 and 4.

[0115] [TPU ratio] Ratio of TPU content to the total amount of resin composition (percentage, mass%) [100 x TPU content / total amount] [TPU amount] The amount of TPU blended (parts by mass) when the total mass of PVC and CPE is 100 parts by mass [Amount of plasticizer] Amount of plasticizer (parts by mass) when the total mass of PVC and CPE is 100 parts by mass

[0116] [CPE amount] Ratio of CPE added to the total amount of resin composition (percentage, mass%) [100 × CPE added / total amount] [PVC+CPE amount] Proportion (percentage, mass%) of the total amount of PVC and CPE added to the total amount of resin composition [100 × (amount of PVC + amount of CPE added) / total amount]

[0117] [Flame retardant content] Amount of flame retardant (parts by mass) when the total mass of PVC and CPE is 100 parts by mass [Amount of metal soap] The amount of metal soap (parts by mass) when the total mass of PVC and CPE is 100 parts by mass [Hydrotalcite / Metallic soap]

[0118] [Amount of stabilizer] Amount of stabilizer (parts by mass) when the total mass of PVC and CPE is 100 parts by mass [MFR difference] MFR multiplication factor of CPEs with different MFRs formulated as CPEs [high MFR / low MFR]

[0119] [CPE Max Cl - Min Cl] The difference between the maximum and minimum chlorine amounts of the CPE blended as CPE (mass%) [Maximum Cl - Minimum Cl] [CPE content ratio (low MFR CPE / high MFR CPE)] Ratio of the amount of CPE with different MFRs to be compounded as CPE [Low MFR CPE / High MFR CPE]

[0120] [Table 1]

[0121] [Table 2]

[0122] [Table 3]

[0123] [Table 4]

[0124] <Evaluation> The cables fabricated in Examples 1 to 10 and Comparative Examples 1 to 4 were evaluated for heat resistance, flame retardancy, heat shrinkability, and cold resistance, as well as impact resistance, crush resistance, and abrasion resistance. Each evaluation was performed as follows. The results are summarized in Tables 2 and 4.

[0125] (Heat resistance) Heat resistance was evaluated using a test in accordance with UL1581. Specifically, a sample (approximately 100 mm long) consisting of only the outer sheath layer of the prepared cable was exposed to a Geer oven at 145°C for 120 hours, and the initial tensile strength and elongation were compared with those after exposure. The tensile strength retention rate (%) and elongation retention rate (%) were then calculated using the following formula. A sample with a tensile strength and elongation retention rate of 50% or higher was deemed "pass," while a sample that did not meet either or neither of these criteria was deemed "fail." Tensile strength retention rate (%) = 100 × (tensile strength after exposure) / (initial tensile strength) Elongation retention rate (%) = 100 × (elongation after the above exposure) / (initial elongation)

[0126] (Flame retardant) Flame retardancy was evaluated using a test in accordance with UL 1581. Specifically, the fabricated cables (approximately 500 mm long) were subjected to the vertical flame retardancy test VW-1 specified in UL 1581 three times, and cables that met the standard all three times were rated as "passed," while cables that did not meet the standard even once were rated as "failed."

[0127] (heat shrinkable) In order to obtain data on heat shrinkage, a cable similar to that of Example 1 was obtained under the following sheath extrusion conditions. The temperature conditions of the cylinder and head were 165°C and 175°C, respectively, the linear speed was 20 m / min, and the draw ratio was 155.

[0128] The draw-down ratio is a value calculated using the formula (1) below. The value of 155 used in this study allows for easy control of the wall thickness during tube extrusion, and is the point at which the sheath tube after sheathing can be controlled to be neither too loose nor too tight. (1) Drawdown ratio = 100 x ((extrusion die diameter - extrusion nipple diameter) - (coating outer diameter - coating inner diameter)) / (coating outer diameter - coating inner diameter))

[0129] For heat shrinkage, the prepared cable was cut into a length of 40 mm, and the shrinkage rate calculated using the formula (2) below was evaluated as passing (◯) if it was within 10%, and failing (×) if it was more than 10%. (2) Shrinkage rate % = 100 × (sheath length (mm) after 30 minutes at 40-136°C) / 40

[0130] (cold resistance) The cold resistance was evaluated by the following test: Specifically, the outer sheath layer was stripped from the fabricated cable to obtain a sample, and the sample was subjected to a destructive test using an embrittlement tester.

[0131] In this example, samples that did not break even at a temperature of -50°C were rated as "pass" (◯), and samples that broke at temperatures higher than that were rated as "fail" (×).

[0132] (impact resistance) The sheath tube was stripped from the prepared 100 mm long cable and cut into a sheet. The sheet was then fixed to a UL2556 compliant anvil surface and subjected to an impact test under the following conditions. After the test, the sheet was visually inspected using a 10x magnifying glass, and those without holes were rated as passing (◯), and those with holes were rated as failing (×). Test conditions: Impact ball 568g, tip R38, drop length 1000mmH

[0133] (Crash resistance) Since the crush resistance test measures the load value until conductivity is achieved during the test, insulated electric wires with the thicknesses shown in Tables 2 and 4 were produced for each example in Tables 2 and 4 using φ0.815 tin-plated copper single wires in a 40 mm extruder at a temperature of 160 to 180°C, separate from the cables of the Examples and Comparative Examples. A crush resistance test conforming to UL2556 was conducted using the produced electric wires. N=5 tests were conducted, and samples with an average load value of 3.6 kN or more were rated as passing (◯), and samples with an average load value of less than 3.6 kN were rated as failing (×).

[0134] (wear resistance) The abrasion resistance test was conducted using the manufactured cables, using a JASO-compliant tape abrasion test with a load of 300 g. The evaluation criteria were: a tape length up to the sheath rupture of 10,000 mm or more was considered pass (◯), and a tape length of less than 10,000 mm was considered fail (×).

[0135] <Evaluation results> The evaluation results are summarized in Tables 2 and 4 as described above. First, Table 4 will be explained. Comparative Examples 1 and 2, which did not use CPE (a1) or TPU (a2), did not provide good results except for heat shrinkability. Comparative Example 3, which did not use TPU (a2), also did not provide good results. Comparative Example 4 is an example in which only CPE (a1) was used, and although various properties were good, good results were not obtained in heat shrinkability.

[0136] In contrast, Examples 1 to 10 in Table 2 achieved good results in all of the properties evaluated above. The conventional PVC sheath material is a system in which a flame retardant is added to the composition of Comparative Example 1, and based on the performance of Comparative Example 1, it is expected that the flame retardancy will be improved. However, no improvement in performance in other properties can be expected. In contrast, it was confirmed that the composition of this embodiment exhibits performance superior to that of conventional materials even when the wall thickness is reduced to about half. Therefore, a resin composition was obtained that leads to a thinner cable, lighter weight, and improved functionality.

[0137] [Appendix 1] One aspect of the present invention is A cable comprising a conductor, an insulating layer coated around the conductor, and an outer jacket layer coated around the insulating layer, the outer skin layer is composed 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) comprises a combination of chlorinated polyethylene (a1) containing two or more types of chlorinated polyethylenes having melt flow rates (MFR) differing by 10 times or more and polyvinyl chloride (a3); a combination of two or more sets of two or more types of chlorinated polyethylene (a1) having melt flow rates (MFR) differing by 10 times or more; or a combination of two or more types of chlorinated polyethylene (a1) having melt flow rates (MFR) differing by 10 times or more and a urethane thermoplastic elastomer (a2) containing at least one selected from adipate-based and lactone-based elastomers; the stabilizer (C) comprises hydrotalcite (c1) and metal soap (c2); The flame retardant (D) includes at least one selected from a metal hydroxide (d1), a brominated flame retardant (d2), amorphous silica (d3), and antimony trioxide (d4). cable.

[0138] [Appendix 2] In Appendix 1, preferably, the base polymer (A) contains 4 parts by mass or more and 1,000 parts by mass or less of the urethane thermoplastic elastomer (a2) per 100 parts by mass of the chlorinated polyethylene (a1) or per 100 parts by mass of the combined amount of the chlorinated polyethylene (a1) and the polyvinyl chloride (a3); The difference between the maximum chlorine content and the minimum chlorine content (mass %) contained in the two or more types of chlorinated polyethylene is 20 mass % or less.

[0139] [Appendix 3] In Appendix 2, preferably, The content of the chlorinated polyethylene (a1) in the flame-retardant resin composition is 3% by mass or more and 70% by mass or less.

[0140] [Appendix 4] In any of Supplementary Notes 1 to 3, preferably, The content of the hydrotalcite (c1) is 1.5 times or more the content of the metal soap (c2), and the content of the metal soap (c2) is 0.1 parts by mass or more and 3 parts by mass or less per 100 parts by mass of the chlorinated polyethylene (a1) or per 100 parts by mass of the combined amount of the chlorinated polyethylene (a1) and the polyvinyl chloride (a3).

[0141] [Appendix 5] In any of Supplementary Notes 1 to 4, preferably, The content of the plasticizer (B) is 5 parts by mass or more and 50 parts by mass or less relative to 100 parts by mass of the chlorinated polyethylene (a1) or 100 parts by mass of the total amount of the chlorinated polyethylene (a1) and the polyvinyl chloride (a3).

[0142] [Appendix 6] In any of Supplementary Notes 1 to 5, preferably, The content of the stabilizer (C) is 2 parts by mass or more and 20 parts by mass or less relative to 100 parts by mass of the chlorinated polyethylene (a1) or 100 parts by mass of the total amount of the chlorinated polyethylene (a1) and the polyvinyl chloride (a3).

[0143] [Appendix 7] In any of Supplementary Notes 1 to 6, preferably, The content of the flame retardant (D) is 1 part by mass or more and 200 parts by mass or less relative to 100 parts by mass of the chlorinated polyethylene (a1) or 100 parts by mass of the total amount of the chlorinated polyethylene (a1) and the polyvinyl chloride (a3).

[0144] [Appendix 8] In any of Supplementary Notes 1 to 7, preferably, The chlorinated polyethylene (a1) has a chlorine content of 20% by mass or more.

[0145] [Appendix 9] In any of Supplementary Notes 1 to 8, preferably, The urethane thermoplastic elastomer (a2) is an adipate type.

[0146] [Appendix 10] In any of Supplementary Notes 1 to 9, preferably, The plasticizer (B) includes a trimellitic acid ester.

[0147] [Appendix 11] In any of Supplementary Notes 1 to 10, preferably, The thickness of the outer skin layer is 0.1 mm or more and 1.4 mm or less.

[0148] [Appendix 12] In any of Supplementary Notes 1 to 11, preferably, The K value of the polyvinyl chloride (a3) ​​is 65.7 to 94.9.

[0149] [Appendix 13] In any of Supplementary Notes 1 to 12, preferably, The urethane thermoplastic elastomer (a2) has a Shore A hardness of 80A to 95A.

[0150] [Appendix 14] Another aspect of the present invention is An electric wire comprising a conductor and an insulating layer coated around 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 base polymer (A) includes a combination of chlorinated polyethylene (a1) containing two or more chlorinated polyethylenes having melt flow rates (MFR) different by 10 times or more and polyvinyl chloride (a3), or a combination of two or more pairs of chlorinated polyethylenes (a1) containing two or more chlorinated polyethylenes having melt flow rates (MFR) different by 10 times or more, or a combination of two or more chlorinated polyethylenes (a1) having melt flow rates (MFR) different by 10 times or more and at least one urethane thermoplastic elastomer (a2) selected from adipate-based and lactone-based elastomers, the stabilizer (C) comprises hydrotalcite (c1) and a metal soap (c2); The flame retardant (D) includes at least one of a metal hydroxide (d1), a brominated flame retardant (d2), amorphous silica (d3), and antimony trioxide (d4). It is an electrical wire.

[0151] [Appendix 15] In any of Supplementary Notes 1 and 2, preferably, the ratio of the amount A of chlorinated polyethylene having a melt flow rate (MFR) of less than 4 / 10 minutes to the amount B of chlorinated polyethylene having a melt flow rate (MFR) of 4 / 10 minutes or more [the amount A of chlorinated polyethylene to the amount B of chlorinated polyethylene (A / B value)] is 0.5 or more and 20 or less.

[0152] The invention made by the inventor has been specifically described above based on the embodiments thereof, but it goes without saying that the present invention is not limited to the above-described embodiments and can be modified in various ways without departing from the spirit of the invention. [Explanation of symbols]

[0153] 1 cable 10 Electric wire 11 Conductor 12 Insulating layer 13 Shielding layer 14 outer layer (sheath) 21. Matrix 22 TPU 23 Calcium-containing compounds

Claims

1. A cable comprising a conductor, an insulating layer coated around the conductor, and an outer jacket layer coated around the insulating layer, the outer skin layer is made 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) comprises a chlorinated polyethylene (a1) containing two or more types of chlorinated polyethylene having melt flow rates (MFR) that differ by 10 times or more, and a urethane thermoplastic elastomer (a2) and / or polyvinyl chloride (a3) ​​containing at least one selected from an adipate-based and a lactone-based elastomer; The stabilizer (C) comprises a hydrotalcite (c1) and a metal soap (c2), The flame retardant (D) contains at least one selected from a metal hydroxide (d1), a brominated flame retardant (d2), amorphous silica (d3), and antimony trioxide (d4), the two or more types of chlorinated polyethylene include a low-MFR chlorinated polyethylene having a melt flow rate (MFR) of less than 4 g / 10 min and a high-MFR chlorinated polyethylene having a higher MFR; a ratio of the amount A of the low MFR chlorinated polyethylene to the amount B of the high MFR chlorinated polyethylene [the amount A to the amount B (A / B)] is 1 or more and 20 or less.

2. 2. The cable of claim 1, The chlorinated polyethylene (a1) has a chlorine content of 20% by mass or more.

3. 3. The cable according to claim 1 or 2, the base polymer (A) contains 4 parts by mass or more and 1,000 parts by mass or less of the urethane thermoplastic elastomer (a2) per 100 parts by mass of the chlorinated polyethylene (a1) or per 100 parts by mass of the combined amount of the chlorinated polyethylene (a1) and the polyvinyl chloride (a3); A cable in which the difference between the maximum chlorine content and the minimum chlorine content (mass %) contained in the two or more types of chlorinated polyethylene is 20 mass % or less.

4. The cable according to any one of claims 1 to 3, The cable, wherein the urethane thermoplastic elastomer (a2) includes an adipate-based urethane thermoplastic elastomer.

5. The cable according to any one of claims 1 to 4, A cable, wherein the plasticizer (B) contains a trimellitic acid ester.

6. The cable according to any one of claims 1 to 5, A cable in which the thickness of the outer sheath layer is 0.1 mm or more and 1.4 mm or less.

7. An electric wire comprising a conductor and an insulating layer coated around the conductor, the insulating layer is made 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) comprises a chlorinated polyethylene (a1) containing two or more types of chlorinated polyethylene having melt flow rates (MFR) that differ by 10 times or more, and a urethane thermoplastic elastomer (a2) and / or polyvinyl chloride (a3) ​​containing at least one selected from an adipate-based and a lactone-based elastomer; The stabilizer (C) comprises a hydrotalcite (c1) and a metal soap (c2), The flame retardant (D) contains at least one selected from a metal hydroxide (d1), a brominated flame retardant (d2), amorphous silica (d3), and antimony trioxide (d4), the two or more types of chlorinated polyethylene include a low-MFR chlorinated polyethylene having a melt flow rate (MFR) of less than 4 g / 10 min and a high-MFR chlorinated polyethylene having a higher MFR; the ratio of the amount A of the low MFR chlorinated polyethylene to the amount B of the high MFR chlorinated polyethylene [the amount A to the amount B (A / B)] is 1 or more and 20 or less.

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