Chlorine-based resin composition, electric wire and electric cable

Abstract

This invention provides chlorinated resin compositions, wires, and cables. The objective of this invention is to provide a material with high durability, exhibiting abrasion resistance under harsh testing conditions, achieved through silane crosslinking in chlorinated polyethylene used as a coating material for wires and cables. The solution of this invention is to use a chlorinated resin composition grafted with a silane coupling agent onto a base polymer. This base polymer is prepared by mixing chlorinated polyethylene with a Mooney viscosity of 85 or higher after 4 minutes of preheating at 121°C, and an ethylene-vinyl acetate copolymer with a melt flow rate of 2.5 g / 10 minutes or less at 190°C and 2.16 kgf, and a melting point of 80°C or higher, in a mass fraction ranging from 90:10 to 50:50.

Description

Technical Field

[0001] This invention relates to chlorinated resin compositions, wires, and cables. Background Technology

[0002] In the coating materials of wires and cables, to improve various properties, especially heat resistance, a cross-linking treatment is sometimes performed to chemically bond the polymer molecules in the coating material. This cross-linking process involves pre-mixing a cross-linking agent in the coating material and then applying energy using heat or electron beams after the cable is coated. However, this method requires large-scale facilities and a large amount of energy. In contrast, silane cross-linking involves pre-combining a silane coupling agent (hereinafter referred to as silane) with the polymer molecules in the coating material, and then, after the cable is coated, allowing the silane molecules to bond together (forming cross-links between polymer molecules) through the action of moisture and a silanol condensation catalyst. Therefore, silane cross-linking does not require large-scale equipment or a large amount of energy, making it an economical and environmentally friendly method.

[0003] In applications requiring flexibility or durability, rubber materials are primarily used as coating materials, and wires and cables manufactured using the aforementioned silane crosslinking method are also employed. The rubber materials used in the coating materials of wires and cables encompass a wide range of applications; among them, chlorinated rubber is known as a high-performance material with excellent flame retardancy and oil resistance.

[0004] Patent document 1 (Japanese Patent Application Publication No. 2013-41794) describes a method for mixing polymers and fillers using a closed mixer with two rotors when manufacturing a resin mixture that constitutes a coating material for electrical wires.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2013-41794 Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] Unlike crosslinking methods that control the degree of crosslinking of polymers through crosslinking dosage or electron beam irradiation, silane crosslinking determines the degree of crosslinking based on the amount of silane grafted onto the polymer molecule, and therefore typically results in a lower degree of crosslinking. In silane crosslinking, free radicals generated during the thermal decomposition of organic peroxides are used to remove hydrogen from the polymer molecule, thereby grafting silane. Therefore, increasing silane is effective for achieving a high degree of crosslinking, as is increasing organic peroxides. However, excessive addition of organic peroxides increases the amount of free radicals generated in the polymer molecule, promoting the bonding of polymer molecules as a side reaction (early crosslinking). This reduces fluidity when coated onto wires and cables, easily leading to poor molding. Therefore, silane crosslinking can impart sufficient crosslinking to the coating material for various functional requirements of wires and cables (such as heat resistance or oil resistance). However, it is unsuitable for products requiring particularly high durability (such as abrasion resistance under harsh conditions), such as cables with large diameters, where achieving such durability is difficult.

[0010] Therefore, the present invention provides a highly durable material that utilizes silane crosslinking in chlorinated polyethylene, which is used as a coating material for wires and cables, and simultaneously meets the abrasion resistance requirements under harsh test conditions.

[0011] Other objects and new features will become clear from the description and accompanying drawings in this specification.

[0012] Methods for solving problems

[0013] [1] One aspect of the present invention is a chlorinated resin composition formed by grafting a silane coupling agent onto a base polymer, wherein the base polymer is formed by mixing chlorinated polyethylene with a Mooney viscosity of 85 or higher after 4 minutes of preheating at 121°C for 1 minute with an ethylene vinyl acetate copolymer with a melt flow rate of 2.5 g / 10 minutes or less at 190°C and 2.16 kgf and a melting point of 80°C or higher in a mass fraction range of 90:10 to 50:50.

[0014] [2] In [1], the above-mentioned chlorine resin composition is added with a silanol condensation catalyst and crosslinked by the action of water.

[0015] [3] In [2], the silanol condensation catalyst is an octyltin compound, and it is added to the chlorine-based resin composition as a masterbatch mixed with the polymer.

[0016] [4] In [1] or [2], the above silane coupling agents contain a methacryloyl group as an organic functional group.

[0017] [5] An electrical wire having a conductor and an insulating material covering the conductor, the insulating material being composed of a chlorinated resin composition grafted with a silane coupling agent onto a base polymer, the base polymer being a mixture of chlorinated polyethylene with a Mooney viscosity of 85 or higher after 4 minutes of preheating at 121°C for 1 minute, and an ethylene vinyl acetate copolymer with a melt flow rate of 2.5 g / 10 minutes or less at 190°C and 2.16 kgf and a melting point of 80°C or higher, in a mass fraction range of 90:10 to 50:50, the chlorinated resin composition being crosslinked by the action of water.

[0018] [6] In [5], the above-mentioned chlorinated resin composition is added with a silanol condensation catalyst and crosslinked by the action of water.

[0019] [7] In [6], the silanol condensation catalyst is an octyltin compound, and is added to the chlorine-based resin composition as a masterbatch mixed with the polymer.

[0020] [8] In [5] or [6], the above silane coupling agents contain a methacryloyl group as an organic functional group.

[0021] [9] In any of [5] to [8], the cross-sectional area of ​​the conductor is greater than 38 mm². 2 .

[0022]

[10] A cable comprising: an electric wire including a conductor and an insulating material covering the conductor, and a covering material covering the electric wire, wherein the covering material is composed of a chlorinated resin composition grafted with a silane coupling agent onto a base polymer, wherein the base polymer is formed by mixing chlorinated polyethylene with a Mooney viscosity of 85 or more after 4 minutes of preheating at 121°C for 1 minute with an ethylene vinyl acetate copolymer with a melt flow rate of 2.5 g / 10 minutes or less at 190°C and 2.16 kgf and a melting point of 80°C or more in a mass fraction range of 90:10 to 50:50, wherein the chlorinated resin composition is crosslinked by the action of water.

[0023]

[11] In

[10] , the above-mentioned chlorine-based resin composition is cross-linked by the action of water with the addition of a silanol condensation catalyst.

[0024]

[12] In

[11] , the silanol condensation catalyst is an octyltin compound, and is added to the chlorine-based resin composition as a masterbatch mixed with the polymer.

[0025]

[13] In

[10] or

[11] , the above silane coupling agents contain a methacryloyl group as an organic functional group.

[0026]

[14] In any of

[10] to

[13] , the cross-sectional area of ​​the conductor is greater than 38 mm². 2 .

[0027] Invention Effects

[0028] According to one aspect of the present invention, a silane-grafted resin composition can provide a material with high durability performance that meets the abrasion resistance requirements under harsh test conditions by using silane crosslinking in chlorinated polyethylene, which is used as a coating material for wires and cables. Attached Figure Description

[0029] Figure 1 This is a schematic diagram showing an extruder used in the manufacture of the cables in this embodiment and comparative examples.

[0030] Figure 2 This is a cross-sectional view showing the manufactured cable.

[0031] Symbol Explanation

[0032] 1. Extruder

[0033] 2 hoppers

[0034] 3 screws

[0035] 5 cylinders

[0036] 8 mold heads

[0037] 9 cores

[0038] 10. Cables. Detailed Implementation

[0039] Hereinafter, embodiments of the present invention will be described in detail based on the accompanying drawings. It should be noted that in all the drawings used to describe the embodiments, components with the same function are labeled with the same symbols, and repeated descriptions are omitted. Furthermore, in the following embodiments, descriptions of the same or identical parts will generally not be repeated unless specifically required.

[0040] (Implementation Method)

[0041] Rubber-insulated cables are a type of general-purpose cable coated with rubber materials. Rubber-insulated cables are classified into stationary and mobile applications based on their intended use. In mobile applications, due to the cable's movement, requirements are placed on resistance to repeated bending and abrasion from friction in various environments. Particularly regarding abrasion resistance, test conditions are set according to the cable's dimensions. Under the Electrical Appliance and Material Safety Law (Appendix 1) and JIS C3327, for multi-core cables with conductor cross-sectional areas exceeding 38 mm²... 2The diameter dimension specifies the most stringent conditions. In order to improve the abrasion resistance of silane cross-linked chlorinated polyethylene material as a cable coating material, the inventors have studied the following method so that it can also cope with such stringent test conditions.

[0042] The first method is to increase the degree of crosslinking. However, if excessive organic peroxides are added to increase the grafted silane, the crosslinking of the polymers may occur, potentially causing defects such as roughness or graininess during cable molding. Increasing the amount of silane added along with organic peroxides may also suppress polymer crosslinking to some extent, but this is not a practical solution as it leads to reduced tensile strength and abrasion resistance due to material softening, decreased electrical insulation, and increased material costs.

[0043] The second method involves using highly crystalline chlorinated polyethylene. Chlorinated polyethylene is primarily manufactured from high-density polyethylene (HDPE), and various grades containing relatively strong crystals from HDPE are also produced. Therefore, the inventors investigated the application of highly crystalline chlorinated polyethylene to silane crosslinking materials. However, it was found that while the abrasion resistance of the coated material improved, the coated material became excessively hardened, significantly compromising the flexibility required for a rubber material, and therefore this application was abandoned.

[0044] The third method is to use chlorinated polyethylene with a high molecular weight. By extending the molecular chains, the entanglement of molecules increases, and improved wear resistance is expected. The inventors investigated its application in silane crosslinking materials and found that although wear resistance improved as expected, the increased viscosity of the coating material resulted in high loads during cable coating using an extruder, making molding difficult. As a countermeasure, one could reduce the viscosity of the material by extrusion at high temperatures, but chlorinated materials, such as chlorinated polyethylene, may deteriorate significantly at high temperatures due to the release of chlorine (in the form of hydrogen chloride), making them impractical. Therefore, to improve the heating fluidity during extrusion, an alloying process was considered using an ethylene vinyl acetate copolymer that exhibits high compatibility with chlorinated polyethylene and, like chlorinated polyethylene, can be grafted with silane using organic peroxides. Through repeated research, the inventors discovered the following conditions: by managing the Mooney viscosity (a molecular weight indicator) in chlorinated polyethylene, the melt flow rate (a heating fluidity indicator) in ethylene vinyl acetate copolymer, and the melting point (which strongly affects abrasion resistance), while appropriately controlling the mixing ratio of the two materials, it is possible to achieve both abrasion resistance under harsh test conditions and good formability during cable extrusion coating.

[0045] <Specific Structure>

[0046] To balance the abrasion resistance of the coating material with good formability during cable extrusion coating, the chlorinated resin composition of this embodiment is formed as follows: The Mooney viscosity (value after 4 minutes of preheating at 121°C for 1 minute) of chlorinated polyethylene and the melting point (above 80°C) and melt flow rate (2.16 kgf at 190°C) of the ethylene-vinyl acetate copolymer are specified as the base polymer, and the mixing ratio of the two materials is controlled within an appropriate range. Here, chlorinated polyethylene is selected as having a practical Mooney viscosity of 120 or less. Physical properties other than Mooney viscosity are not limited, but a chlorine content of 20–45% by mass and a crystallinity (DSC heat of fusion) of 5 J / g or less are acceptable. Furthermore, regarding chlorinated polyethylene, from the perspective of balancing flame retardancy and flexibility, a chlorine content of 25–40% by mass and a crystallinity of 2 J / g or less are more preferable. In addition, in practical applications, substances with a melting point below 95°C and a melt flow rate of 0.5 g / 10 min or higher are selected for ethylene-vinyl acetate copolymers, and there are no restrictions on physical properties other than melting point and melt flow rate.

[0047] Regarding materials, melt flow rate is an indicator of fluidity (an indicator of molecular weight (molecule length)). A high melt flow rate indicates high fluidity, low molecular weight (short molecules), and reduced wear resistance. In other words, longer molecules are more prone to cross-linking, forming connections between molecules, and physically entanglement, thus improving the material's wear resistance. Here, by using an ethylene-vinyl acetate copolymer with a melt flow rate of less than 2.5 g / 10 min at 190°C and 2.16 kgf, the wear resistance of the chlorinated resin composition is improved.

[0048] In addition to molecular weight, increasing the melting point, which is related to the amount of crystallization within the molecule, leads to increased crystallinity and improved wear resistance of the material. This is because crystals are formed by molecular folding and exist as the robust components within the material (for areas prone to wear).

[0049] As a silane coupling agent, any silane coupling agent possessing both an organic functional group exhibiting an addition reaction with a free radical and an alkoxy group can be used. For example, general silane coupling agents possessing both organic functional groups such as vinyl, methacryl, acryloyl, or styryl and alkoxy groups such as methoxy or ethoxy can be used. Specifically, examples include vinyltrimethoxysilane, vinyltriethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, 3-methacryloyloxypropyltriethoxysilane, 3-methacryloyloxypropylmethyldimethoxysilane, 3-methacryloyloxypropylmethyldiethoxysilane, 3-acryloyloxypropyltrimethoxysilane, or p-styryltrimethoxysilane or mixtures thereof. However, as long as both the aforementioned organic functional group and alkoxy group are present, it can also be an alkoxy oligomer; there is no limitation on the above compounds.

[0050] In the above-mentioned chlorinated resin composition (silane-grafted rubber composition), additives such as plasticizers, lubricants, reinforcing agents, fillers, or flame retardants, represented by organic peroxides for grafting silanes or hydrogen chloride scavengers for efficiently capturing hydrogen chloride that may be generated by chlorinated polyethylene, can be mixed in.

[0051] Here, as organic peroxides, dicumyl peroxide, 1,1-di(tert-butylperoxy)cyclohexane, tert-butyl peroxyisopropyl carbonate, tert-amyl peroxyisopropyl carbonate, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, di-tert-butyl peroxide, di-tert-amyl peroxide, 1,1-di(tert-amylperoxy)cyclohexane, or tert-butylperoxycarbonate 2-ethylhexyl, etc., can be used. They can be used alone or in combination of two or more, but there are no limitations.

[0052] Examples of hydrogen chloride scavengers include epoxy compounds, hydrotalcites, lead-containing compounds such as tribasic lead sulfate, tin-containing compounds, or metal soaps.

[0053] Furthermore, by adding antioxidants or silanol condensation catalysts to the above-mentioned chlorinated resin composition, it is possible to improve heat resistance and promote crosslinking reaction. These may hinder silane grafting reaction or become the cause of poor molding, so it is preferable to mix them with the chlorinated resin composition during final molding (in the case of wires and cables, when extruding and coating the conductor or cable core).

[0054] Examples of suitable catalysts for silanol condensation include group II elements such as magnesium and calcium, group VII elements such as cobalt and iron, or elements or metal compounds such as tin, zinc, and titanium, metal salts of octanoic acid or adipic acid, amine compounds, and acids. More specifically, suitable catalysts for silanol condensation include dioctyltin dinedecanoate, dibutyltin dilaurate, dibutyltin diacetate, dibutyltin dioctanoate, stannous acetate, stannous octanoate, lead naphthenate, zinc octanoate, cobalt naphthenate, ethylamine, dibutylamine, hexylamine, pyridine, sulfuric acid, hydrochloric acid, and other inorganic acids, as well as toluenesulfonic acid, acetic acid, stearic acid, maleic acid, and other organic acids.

[0055] As described above, in this embodiment, a chlorinated resin composition is provided, which is formed by grafting a silane coupling agent onto a base polymer. The base polymer is formed by mixing chlorinated polyethylene with a Mooney viscosity of 85 or higher after 4 minutes of preheating at 121°C for 1 minute, and an ethylene-vinyl acetate copolymer with a melting point of 80°C or higher and a melt flow rate of 2.5 g / 10 minutes or less at 190°C and 2.16 kgf, in a mass fraction ranging from 90:10 to 50:50. The chlorinated resin composition having this configuration can be used as an insulator or sheathing material for the coating of wires and cables.

[0056] Furthermore, silane coupling agents with unsaturated bonds in their molecules that react with free radicals have high flash points. As silane coupling agents with excellent fire safety when compounded with polymers, silane coupling agents containing methacryl groups can be used. Examples of such silane coupling agents include 3-methacryloyloxypropyltrimethoxysilane and 3-methacryloyloxypropyltriethoxysilane.

[0057] Furthermore, tin-based compounds with high catalytic activity can be used as silanol condensation catalysts, and octyltin compounds that do not contain dibutyltin, which is considered to have a high environmental impact, can be used. Examples of such octyltin compounds include dioctyltin dineodecanate or dioctyltin dilaurate. Additionally, since the silanol condensation catalyst can be added in small amounts relative to the chlorine-based resin composition, it is useful as a high-concentration masterbatch added to the chlorine-based resin composition from the viewpoint of quality stability and industrial applications.

[0058] Furthermore, the chlorine-based resin composition of this embodiment can be applied to multi-core cables with a conductor cross-sectional area exceeding 38 mm² under the most stringent abrasion test conditions specified in the Electrical Appliance and Material Safety Law (Appendix 1) and JIS C3327. 2 Materials used for the coating of wires and cables with large diameters.

[0059] <Preparation Method of Chlorine-Based Resin Composition and Cable>

[0060] The following describes the manufacturing method of the chlorine-based resin composition and the cable.

[0061] The following steps can be performed sequentially: mixing silane and various additives in a mixture of chlorinated polyethylene and ethylene vinyl acetate copolymer; silane grafting treatment; and manufacturing and post-processing of cables using the resulting composite. The following conditions are an example and are not intended to limit the process.

[0062] (Mixing of silanes and various additives)

[0063] Chlorinated polyethylene, ethylene-vinyl acetate copolymer, silane coupling agent, organic peroxide, hydrogen chloride scavenger, plasticizer, lubricant, reinforcing agent, filler, and flame retardant were added to a 25L pressure kneader (kneader tank temperature adjusted to 100°C), and kneaded under pressure at a rotor speed of 10 rpm for 10 minutes. Here, the organic peroxide is pre-dissolved in the silane coupling agent, which improves its dispersibility in the polymer. Furthermore, by allowing the silane coupling agent (dissolved organic peroxide) to permeate into the fillers such as reinforcing agents during addition, the adsorption of the silane coupling agent into the kneading tank is reduced. Additionally, by adding the ethylene-vinyl acetate copolymer at the end of the mixing process, the viscosity of the material during additive mixing is increased, thereby improving dispersibility. These conditions are just one example and are not limiting.

[0064] (Silane grafting treatment)

[0065] After the above mixing, the same equipment (a 25L capacity pressure kneader, with the kneader temperature adjusted to 100°C) is used to mix and heat the material to 180°C at a rotor speed of 30 rpm. This operation can be carried out continuously without discharging the material after the above mixing. After reaching 180°C, the speed is reduced, and isothermal mixing is performed for 3 minutes and 30 seconds, thereby dynamically grafting the silane coupling agent onto the polymer. After grafting, the material is quickly discharged into the hopper of a single-screw extruder, extruded into a filament, water-cooled, and then granulated to produce granules of the chlorinated resin composition. Here, the granulation method is not limited to the above method; for example, granules can be produced using a thermal cutting device without water cooling. In addition, a release agent can be used to prevent the granules from sticking together. The release agent is not limited to its composition or form such as powder, liquid, or mist; for example, using talc or the like is effective for economic reasons.

[0066] (Preparation of masterbatch pellets)

[0067] In a 25L pressure kneader (with the kneader tank temperature adjusted to 100°C), the polymer (and, in the case of chlorinated materials, a hydrogen chloride scavenger), antioxidant, and silanol condensation catalyst are added and kneaded at 10 rpm for 10 minutes. The polymer can be the same chlorinated polyethylene and ethylene vinyl acetate copolymer as the main material, without particular limitation. Similar to the silane grafting treatment described above, the kneaded material is granulated into pellets. To prevent the pellets from sticking together, a release agent can be used.

[0068] (Cable manufacturing and cross-linking process)

[0069] A conductor with a cross-sectional area of ​​50 mm² is formed by twisting together multiple tin-plated soft copper wires. 2 An ethylene-propylene rubber copolymer mixture is extruded to a conductor with an outer diameter of 10.4 mm to serve as insulation, with a thickness of 1.5 mm. Next, using a single-screw extruder with a screw diameter of 90 mm, a mixture of chlorinated resin composition and masterbatch particles is dry-blended to a thickness of 3.3 mm and extruded onto a cable core consisting of three cross-linked core wires stranded together, thereby producing a cable. The finished cable has an outer diameter of approximately 36 mm. The manufactured cable undergoes cross-linking treatment by being stored at 60°C in a saturated steam atmosphere for 24 hours. That is, after cable coating, the silanes combine with each other (forming cross-links between polymer molecules) through the action of moisture and a silanol condensation catalyst. In other words, the chlorinated resin composition is cross-linked, becoming a silane cross-linked rubber composition. It should be noted that the dry mixing performed here involves mixing two or more types of particles in a bag or kettle, either manually or mechanically.

[0070] To achieve the above-described mixing and grafting processes, commonly used mixing and reaction equipment such as roller presses (other than kneaders), extruders, mixers, or autoclaves can be used. Furthermore, the mixing and grafting conditions are not limited in any way as described above. Similarly, the above-described cable manufacturing method is an example where the extruder, cable core, cable structure, and crosslinking treatment conditions are not limited in any way as described above. Here, the use of the chlorinated resin composition of this embodiment as the sheath material in cable manufacturing has been described, but this chlorinated resin composition can also be used as an insulator that serves as a conductor coating material. That is, the chlorinated resin composition can be used in both the insulator constituting the core and the sheath covering the core.

[0071] <Example>

[0072] The following uses Figure 1 , Figure 2 Examples and comparative examples of this embodiment are described in Tables 1 to 3.

[0073] The inventors and others utilized Figure 1 , Figure 2A chlorinated resin composition, masterbatch, and cable were prepared using the equipment, cable structure, cable manufacturing extrusion conditions, and materials shown in Tables 1 to 3. The properties of the cable, which was then crosslinked with the silane-grafted composition, were evaluated as follows.

[0074] Figure 1 The schematic diagram shows an extruder used in the manufacture of the cables used in this embodiment and the comparative example. For example... Figure 1 As shown, the extruder 1 includes a cylinder 5, a screw 3 rotatably mounted within the cylinder 5, a hopper 2 for supplying material into the cylinder 5, and a right-angle die head 7. Furthermore, the extruder 1 includes a neck 6 between the right-angle die head 7 and the screw 3, and a perforated plate 4 between the neck 6 and the screw 3. The right-angle die head 7 has a die 8, and a core 9, i.e., a conductor covered by an insulator, passes through the right-angle die head 7, is covered by a sheath within the right-angle die head 7, passes through the die head 8, and exits from the right-angle die head 7 as a cable 10.

[0075] Figure 2 This is a cross-sectional view showing a cable manufactured using extruder 1. (Example) Figure 2 As shown, cable 10 is formed by twisting three cores 9 together and covering them with a sheath 13. Core 9 has a cross-sectional area of ​​50 mm². 2 The conductor 11 and the insulator 12 surrounding it constitute a structure. The insulator 12 is, for example, a mixture of ethylene-propylene rubber copolymer. The sheath 13 covers all three cores 9.

[0076] The diameter of conductor 11 is, for example, 10.4 mm. The diameter of core 9 is, for example, 13.4 mm. The diameter of cable 10 is, for example, 36 mm. The shortest distance between core 9 and the outer circumference of sheath 13 is, for example, 3.3 mm.

[0077] Table 1 below shows the extrusion conditions in the cable extrusion process. Table 2 shows the fit and evaluation results for Examples 1-7. Table 3 shows the fit and evaluation results for Example 8 and Comparative Examples 1-6. The flanges listed in Table 1 are the ends of cylinder 5 and the ends on the neck 6 side.

[0078] [Table 1]

[0079]

[0080] [Table 2]

[0081]

[0082] [Table 3]

[0083]

[0084] Of the products shown in Tables 2 and 3, “CM3685” and “CM352L” are manufactured by Keli Chemical (China), “ELASLEN401A” is manufactured by Showa Denko, and “EV270”, “EV460”, “EV450”, “V5274”, and “EV550” are manufactured by Mitsui & Dow Chemical. Additionally, of the products shown in Tables 2 and 3, “VF-120T” is manufactured by Ube Maruzen Polyethylene, “KBM-503” is manufactured by Shin-Etsu Chemical Industry, “DCP” is manufactured by Nippon Oil, and “Carbon Black” is HTC#S (arithmetic mean particle size 68nm) manufactured by Nippon Iron & Carbon.

[0085] The Mooney viscosity of CM3685 is 85, that of CM352L is 55, and that of ELASLEN 401A is 115. Additionally, EV270 has a melting point of 72°C and a melt flow rate of 1 g / 10 min. VF120T has a melting point of 85°C and a melt flow rate of 1 g / 10 min. EV460 has a melting point of 84°C and a melt flow rate of 2.5 g / 10 min. EV450 has a melting point of 84°C and a melt flow rate of 15 g / 10 min. V5274 has a melting point of 89°C and a melt flow rate of 0.8 g / 10 min. EV550 has a melting point of 89°C and a melt flow rate of 15 g / 10 min.

[0086] (1) Wear characteristics (wear resistance)

[0087] The cross-linked cable was tested according to JISC3005. The weight was 10 kg, and the grinding disc rotated 1000 times. After the test, the case where the insulation was not exposed was marked as good (marked with 〇 or ◎ in Tables 2 and 3), and the case where the insulation was exposed was marked as bad (marked with × in Tables 2 and 3). In addition, for the case where the insulation was not exposed, the depth of the worn part was calculated using a micrometer using the following formula (1), and the case where it was less than 3.0 mm was judged as the case with particularly excellent wear resistance (marked with ◎ in Tables 2 and 3).

[0088] Wear depth = cable outer diameter before test - cable thickness of the worn part after test ... (1)

[0089] (2) Mooney viscosity (processability)

[0090] The Mooney viscosity (value after 4 minutes of preheating following 1 minute of silane grafting) of the composition was measured at 130°C. Lower Mooney viscosity results in lower load during cable extrusion, indicating better processability. In actual production, lower viscosity leads to higher discharge rates and increases cable extrusion speed. Furthermore, lower viscosity offers advantages such as reduced residual extrusion strain during high-speed extrusion and reduced thermal shrinkage after cable laying. A Mooney viscosity less than 60 was rated as good (marked with 〇 or ◎ in Tables 2 and 3), while a viscosity greater than 60 was rated as poor (marked with × in Tables 2 and 3). Additionally, a Mooney viscosity less than 50 was considered to have exceptionally excellent processability (marked with ◎ in Tables 2 and 3).

[0091] (3) Comprehensive judgment

[0092] In (1) and (2) above, the case where both characteristics are good is marked as qualified (marked by 〇 or ◎ in Tables 2 to 3), and the case where either one is unqualified is marked as unqualified (marked by × in Tables 2 to 3).

[0093] As shown in the examples, the wear resistance increases with the increase of the amount of chlorinated polyethylene added, and the processability increases with the increase of the amount of ethylene vinyl acetate copolymer added. Furthermore, it is known that by setting the mixing mass ratio of chlorinated polyethylene to ethylene vinyl acetate copolymer to 90:10 to 50:50, both wear resistance and processability can be balanced. Moreover, by adjusting the ratio to 70:30, excellent properties in both wear resistance and processability can be obtained.

[0094] In contrast, Comparative Examples 1 and 2 show that excessively increasing the addition ratio of chlorinated polyethylene results in poor processability, while excessively increasing the addition ratio of ethylene-vinyl acetate copolymer results in poor abrasion resistance. Furthermore, Comparative Example 3 shows that excessively decreasing the Mooney viscosity of chlorinated polyethylene (excessively decreasing the molecular weight) reduces abrasion resistance. Additionally, Comparative Examples 4-6 confirm that lowering the melting point of the ethylene-vinyl acetate copolymer or increasing the melt flow rate reduces abrasion resistance.

[0095] In Comparative Example 3, the Mooney viscosity of CM352L was 85 or less (specifically 55), therefore it was judged to have poor abrasion resistance. Furthermore, in Comparative Examples 5 and 6, the melt flow rate of the ethylene vinyl acetate copolymer was not 2.5 g / 10 min or less, therefore it was judged to have poor abrasion resistance.

[0096] As can be seen from the above, in order to balance wear resistance and processability, in addition to the Mooney viscosity (molecular weight) of chlorinated polyethylene itself, the melting point of ethylene-vinyl acetate copolymer, and melt flow rate, the mixing ratio of the two materials is also important. By properly controlling them, the desired properties can be obtained.

[0097] In this embodiment, even when using silane crosslinking, which is an energy-saving and economical method for crosslinking wires and cables, it is possible to manufacture chlorine-based resin compositions that meet the requirements of abrasion resistance under harsh conditions and have good processability, as well as wires and cables coated with such chlorine-based resin compositions.

[0098] This invention is not limited to the above-described embodiments and examples, and various modifications can be made without departing from its spirit.

Claims

1. A chlorinated resin composition comprising grafting a silane coupling agent onto a base polymer, wherein the base polymer is a mixture of chlorinated polyethylene having a Mooney viscosity of 85 or higher and 120 or lower after 4 minutes of preheating at 121°C for 1 minute, and an ethylene vinyl acetate copolymer having a melt flow rate of 0.5 g / 10 min or higher and 2.5 g / 10 min or lower at 190°C and 2.16 kgf, and a melting point of 80°C or higher and 95°C, in a mass fraction ranging from 90:10 to 50:

50.

2. The chlorinated resin composition according to claim 1, wherein a silanol condensation catalyst is added and crosslinking is achieved through the action of water.

3. The chlorinated resin composition according to claim 2, wherein the silanol condensation catalyst is an octyltin compound, and is added to the chlorinated resin composition as a masterbatch mixed with the polymer.

4. The chlorine-based resin composition according to claim 1 or 2, wherein the silane coupling agent contains a methacryl group as an organic functional group.

5. An electrical wire having a conductor and an insulating material covering the conductor, The insulating material is composed of a chlorinated resin composition grafted with a silane coupling agent onto a base polymer. The base polymer is a mixture of chlorinated polyethylene with a Mooney viscosity of 85 or higher and 120 or lower after 4 minutes of preheating at 121°C for 1 minute, and an ethylene-vinyl acetate copolymer with a melt flow rate of 0.5 g / 10 min or higher and 2.5 g / 10 min or lower at 190°C and 2.16 kgf, and a melting point of 80°C or higher and 95°C, in a mass fraction ranging from 90:10 to 50:

50. The chlorine-based resin composition is cross-linked by the action of water.

6. The wire according to claim 5, wherein the chlorinated resin composition contains a silanol condensation catalyst and is cross-linked by the action of water.

7. The wire according to claim 6, wherein the silanol condensation catalyst is an octyltin compound, and is added to the chlorine-based resin composition as a masterbatch mixed with the polymer.

8. The wire according to claim 5 or 6, wherein the silane coupling agent contains a methacryl group as an organic functional group.

9. The wire according to claim 5 or 6, wherein the cross-sectional area of ​​the conductor is greater than 38 mm². 2 .

10. A cable comprising: a wire including a conductor and an insulating material covering the conductor, and a covering material covering the wire. The coating material is composed of a chlorinated resin composition grafted with a silane coupling agent onto a base polymer. The base polymer is a mixture of chlorinated polyethylene with a Mooney viscosity of 85 or higher and 120 or lower after 4 minutes of preheating at 121°C for 1 minute, and an ethylene-vinyl acetate copolymer with a melt flow rate of 0.5 g / 10 min or higher and 2.5 g / 10 min or lower at 190°C and 2.16 kgf, and a melting point of 80°C or higher and 95°C, in a mass fraction ranging from 90:10 to 50:

50. The chlorine-based resin composition is cross-linked by the action of water.

11. The cable according to claim 10, wherein the chlorinated resin composition contains a silanol condensation catalyst and is cross-linked by the action of water.

12. The cable according to claim 11, wherein the silanol condensation catalyst is an octyltin compound and is added to the chlorine-based resin composition as a masterbatch mixed with the polymer.

13. The cable according to claim 10 or 11, wherein the silane coupling agent contains a methacryl group as an organic functional group.

14. The cable according to claim 10 or 11, wherein the cross-sectional area of ​​the conductor is greater than 38 mm². 2 .

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