JP2022152547A - Chlorine-based resin composition, electric wire, and cable - Google Patents

Abstract

To provide a chlorinated polyethylene to be used for a covering material of an electric wire and cable that has high durability satisfying abrasion resistance under severe test conditions even when treated by a silane cross-linking method.SOLUTION: A chlorine-based resin composition is produced by grafting a silane coupling agent to a base polymer obtained by mixing a chlorinated polyethylene having a Mooney viscosity of 85 or more at 121°C and at four minutes after one minute preheating and an ethylene-vinyl acetate copolymer having a melt mass flow rate of 2.5 g/10 min or less under a condition of 190°C and 2.16 kgf and a melting point of 80°C or higher in the range of 90:10-50:50 by mass fraction.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to a chlorine-based resin composition, an electric wire and a cable.

Coating materials for electric wires and cables are sometimes subjected to a cross-linking treatment to chemically bond the molecules of the polymer, which is the coating material, in order to improve various properties such as heat resistance. The cross-linking treatment is a method in which a cross-linking agent is added to the coating material in advance, and energy is applied by heat or electron beams after the cable is covered. However, this method requires large-scale facilities and a large amount of energy. On the other hand, in the silane cross-linking method, a silane coupling agent (hereinafter referred to as silane) is preliminarily bound to the polymer molecules that are the coating material, and after the cable is coated, the silanes are bonded together by the action of moisture and a silanol condensation catalyst (polymer Intermolecular cross-links are formed). For this reason, the silane cross-linking method does not require large-scale facilities and a large amount of energy, and is an economical and environmentally friendly production method.

In applications where flexibility or durability is required, rubber materials are mainly used as coating materials, and electric wires and cables are also manufactured by the silane cross-linking method. There are a wide variety of rubber materials used for the coating of electric wires and cables. Among them, chlorinated rubber is known as a highly functional material with excellent flame retardancy and oil resistance.

In Patent Document 1 (Japanese Patent Application Laid-Open No. 2013-41794), when producing a resin mixture that constitutes a coating material for electric wires, a closed kneader equipped with two rotors is used to knead a polymer and a filler. is stated.

JP 2013-41794 A

Unlike the cross-linking method, which controls the degree of polymer cross-linking by controlling the amount of cross-linking agent or the dose of electron beam irradiation, the degree of cross-linking in the silane cross-linking method is determined according to the amount of silane grafted to the polymer molecule, so the degree of cross-linking is relatively low. It is customary to become In the silane cross-linking method, radicals generated when an organic peroxide is thermally decomposed are used to extract hydrogen from polymer molecules, thereby grafting silane. Therefore, in order to obtain a high degree of cross-linking, it is effective to increase not only silane but also organic peroxide. However, if the amount of organic peroxide is excessively increased and the amount of radicals generated in the polymer molecules increases, the bonding between polymer molecules (premature cross-linking), which is a side reaction, will be promoted, and fluidity will decrease when coating wires and cables. It becomes easy to cause poor molding. For this reason, the silane cross-linking method can give the coating material a sufficient degree of cross-linking for many properties (heat resistance, oil resistance, etc.) required for the functions of electric wires and cables. However, it is unsuitable for products that require a high degree of durability (such as wear resistance under severe conditions), such as large-diameter cables, and it has been difficult to achieve such durability.

Therefore, the present invention is to provide a highly durable material that satisfies wear resistance under severe test conditions while utilizing a silane cross-linking method in chlorinated polyethylene, which is a coating material for electric wires and cables. be.

Other objects and novel features will become apparent from the description and accompanying drawings herein.

[1] A chlorinated resin composition of one embodiment of the present invention is prepared by mixing a chlorinated polyethylene having a Mooney viscosity of 85 or more after 4 minutes after preheating at 121°C for 1 minute and 190°C at 2.16 kgf. and an ethylene-vinyl acetate copolymer having a melt mass flow rate of 2.5 g/10 min or less and a melting point of 80° C. or more in a mass fraction range of 90:10 to 50:50. A silane coupling agent is grafted onto a polymer.

[2] In [1], a silanol condensation catalyst is added to the chlorine-based resin composition, and crosslinked by the action of moisture.

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

[4] In [1] or [2], the silane coupling agent contains a methacryl group as the organic functional group.

[5] A conductor and an insulator covering the conductor, wherein the insulating material is chlorinated polyethylene having a Mooney viscosity of 85 or more after 4 minutes of preheating at 121 ° C. for 1 minute, and 190 and an ethylene-vinyl acetate copolymer having a melt mass flow rate of 2.5 g/10 min or less under conditions of 2.16 kgf and a melting point of 80° C. or higher, in a mass fraction of 90:10 to 50: An electric wire comprising a chlorine-based resin composition in which a silane coupling agent is grafted to a base polymer mixed in the range of 50, and the chlorine-based resin composition is crosslinked by the action of moisture.

[6] In [5], a silanol condensation catalyst is added to the chlorine-based resin composition and crosslinked by the action of moisture.

[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.

[8] In [5] or [6], the silane coupling agent contains a methacryl group as the organic functional group.

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

[10] An electric wire including a conductor, an insulating material covering the conductor, and a covering material covering the electric wire, the covering material being preheated at 121 ° C. for 1 minute and after 4 minutes A chlorinated polyethylene having a Mooney viscosity of 85 or more, and an ethylene-vinyl acetate copolymer having a melt mass flow rate of 2.5 g/10 min or less under conditions of 190°C and 2.16 kgf and a melting point of 80°C or more. is a base polymer mixed in a mass fraction range of 90:10 to 50:50, and a chlorine-based resin composition in which a silane coupling agent is grafted, and the chlorine-based resin composition is free of moisture. A cable that is crosslinked by action.

[11] In [10], a silanol condensation catalyst is added to the chlorine-based resin composition, and crosslinked by the action of moisture.

[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.

[13] In [10] or [11], the silane coupling agent contains a methacryl group as the organic functional group.

[14] In any one of [10] to [13], the cross-sectional area of the conductor is greater than 38 mm ² .

According to the silane graft resin composition of one aspect of the present invention, while utilizing the silane cross-linking method in chlorinated polyethylene that is a coating material for electric wires and cables, high durability that satisfies wear resistance under severe test conditions Materials with performance can be provided.

FIG. 2 is a schematic diagram showing an extruder for producing cables used in the present embodiment and comparative examples. It is a sectional view showing a produced cable.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, in all the drawings for describing the embodiments, members having the same functions are denoted by the same reference numerals, and repeated description thereof will be omitted. In addition, in the following embodiments, the description of the same or similar parts will not be repeated in principle unless particularly necessary.

(Embodiment)
A general-purpose cable coated with a rubber material is a cabtyre cable. Cabtyre cables are classified into fixed and movable cables according to their intended use. Of these, movable cables are required to have resistance to repeated bending and wear resistance to rubbing under various environments because the cables themselves move. Especially for abrasion resistance, the test conditions are set according to the size of the cable. According to the Electrical Appliance and Material Safety Law (Appended Table 1) and JISC3327, large-diameter multi-core cables with a conductor cross-sectional area exceeding ^38mm2 are considered the most severe. conditions are stipulated. In order to be able to cope with such severe test conditions, the present inventors investigated the following method in order to improve the abrasion resistance of the silane-crosslinked chlorinated polyethylene material used as the cable covering material.

The first method is to increase the degree of cross-linking. If an excessive amount of organic peroxide is added in an attempt to increase the amount of silane to be grafted, cross-linking between polymers may proceed, causing defects such as rough appearance or bumps during cable molding. By increasing the amount of silane added together with the organic peroxide, cross-linking between polymers may be suppressed to some extent. It cannot be said to be a practical countermeasure because it causes an increase in

A second method is the application of chlorinated polyethylene with high crystallinity. Chlorinated polyethylene is mainly produced using high-density polyethylene as a raw material, and various grades in which relatively strong crystals derived from high-density polyethylene remain are also produced. Therefore, the present inventors have investigated the application of chlorinated polyethylene having high crystallinity to the silane cross-linking material. However, although the abrasion resistance of the covering material was improved, it was found that the covering material became excessively hard and the flexibility required of rubber materials was significantly impaired, so we abandoned the application.

A third method is the application of chlorinated polyethylene with high molecular weight. By lengthening the molecular chains, the entanglement between molecules increases, which is expected to improve wear resistance. When the present inventors examined the application to silane cross-linking materials, wear resistance improved as expected, but the increased viscosity of the coating material added a high load during cable coating in an extruder, making molding difficult. It turned out to be As a countermeasure, it is possible to reduce the viscosity of the material by extruding it at a high temperature, but chlorine-based materials such as chlorinated polyethylene desorb chlorine (as hydrogen chloride) in a high-temperature environment, resulting in significant deterioration. Not practical because of the potential. Therefore, an ethylene-vinyl acetate copolymer that exhibits high compatibility with chlorinated polyethylene to improve heat fluidity during extrusion and that can be silane-grafted using an organic peroxide in the same way as chlorinated polyethylene is used. We thought of making it into an alloy and grafting silane to this alloy material. As a result of repeated studies, the present inventors have found that chlorinated polyethylene has a strong effect on Mooney viscosity, which is an index of molecular weight, and ethylene-vinyl acetate copolymer has a strong effect on melt mass flow rate, which is an index of heat fluidity, and abrasion resistance. By properly controlling the mixing ratio of both materials while controlling the melting point, which is correlated with the crystal content, it is possible to achieve both wear resistance under severe test conditions and good moldability during cable extrusion coating. found the conditions.

<Specific configuration>
The chlorinated resin composition of the present embodiment uses chlorinated polyethylene as a base polymer with Mooney viscosity (121° C., 1 min. 4 minutes after preheating), the melting point of the ethylene-vinyl acetate copolymer (80°C or higher), and the melt mass flow rate (190°C, 2.16 kgf), while setting the mixing ratio of both materials within an appropriate range. It was formed by controlling Here, the chlorinated polyethylene is selected to have a practical Mooney viscosity of about 120 or less, and the physical properties other than the Mooney viscosity are not limited. should be 5 J/g or less. Further, with respect to chlorinated polyethylene, it is more preferable that the chlorine content is 25 to 40% by mass and the crystal content is 2 J/g or less from the balance of flame retardancy and flexibility. Also, the ethylene-vinyl acetate copolymer is practically selected to have a melting point of 95° C. or less and a melt mass flow rate of 0.5 g/10 min or more.

For materials, melt mass flow rate is an indicator of fluidity (an indicator of molecular weight (molecular length)). When the melt mass flow rate is large, the fluidity is high and the molecular weight is small (the molecule is short), which lowers the wear resistance. In other words, the longer the molecule, the easier it is to be crosslinked, the easier it is to form a connection between the molecules, and the easier it is for the molecules to be physically entangled with each other, which improves the wear resistance of the material. Here, the abrasion resistance of the chlorine-based resin composition is improved by using an ethylene-vinyl acetate copolymer having a melt mass flow rate of 2.5 g/10 min or less under conditions of 190° C. and 2.16 kgf. .

In addition to the molecular weight, increasing the melting point, which correlates with the amount of crystals in the molecule, increases the amount of crystals and improves the abrasion resistance of the material. This is because a crystal is a folded molecule and exists as a strong portion (a portion that is resistant to wear) in the material.

Any silane coupling agent may be used as long as it has an organic functional group and an alkoxy group that undergo addition reaction to radicals. For example, a general-purpose silane coupling agent having both an organic functional group such as a vinyl group, a methacryl group, an acryl group or a styryl group and an alkoxy group such as a methoxy group or an ethoxy group is used. Specifically, vinyltrimethoxysilane, vinyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropylmethyldiethoxy silane, 3-acryloxypropyltrimethoxysilane or p-styryltrimethoxysilane or mixtures thereof. However, if it has both the above-mentioned organic functional group and an alkoxy group, it may be an alkoxy oligomer, and is not limited to the above compounds.

The chlorine-based resin composition (silane-grafted rubber composition) contains an organic peroxide for grafting silane, or a hydrogen chloride scavenger for efficiently capturing hydrogen chloride that may be generated from chlorinated polyethylene. Additives such as agents, plasticizers, lubricants, reinforcing agents, fillers or flame retardants can be mixed.

Here, the organic peroxides include dicumyl peroxide, 1,1-di(t-butylperoxy)cyclohexane, t-butylperoxyisopropyl carbonate, t-amylperoxyisopropyl carbonate, 2,5 dimethyl 2 ,5 di(t-butylperoxy)hexane, di-t-butylperoxide, di-t-amylperoxide, 1,1-di(t-amylperoxy)cyclohexane, or t-butylperoxy2 - Ethylhexyl carbonate and the like can be used. These may be used alone or in combination of two or more, but are not limited in any way.

Hydrogen chloride scavengers include epoxy group-containing compounds, hydrotalcites, lead-containing compounds such as tribasic lead sulfate, tin-containing compounds, metal soaps, and the like.

Furthermore, by adding an antioxidant or a silanol condensation catalyst to the chlorine-based resin composition, heat resistance can be improved and the cross-linking reaction can be promoted. These may inhibit the Silang graft reaction or cause molding defects, so it is recommended to mix them with the chlorine resin composition during the final molding (in the case of wires and cables, when extruding and covering the conductor or cable core). is good.

Examples of silanol condensation catalysts include group II such as magnesium and calcium, group VII such as cobalt and iron, elements or metal compounds such as tin, zinc and titanium, metal salts of octylic acid or adipic acid, amine compounds, acids, and the like. mentioned. More specifically, silanol condensation catalysts include dioctyltin dineodecanoate, dibutyltin dilaurate, dibutyltin diacetate, dibutyltin dioctaate, stannous acetate, stannous caprylate, lead naphthenate, caprylic acid. Inorganic acids such as zinc, cobalt naphthenate, ethylamine, dibutylamine, hexylamine, pyridine, sulfuric acid and hydrochloric acid, and organic acids such as toluenesulfonic acid, acetic acid, stearic acid and maleic acid are used.

As described above, in the present embodiment, chlorinated polyethylene having a Mooney viscosity of 85 or higher after 4 minutes of preheating at 121° C. for 1 minute and 2.16 kgf at 190° C. and a melting point of 80° C. or higher A silane coupling agent is added to a base polymer obtained by mixing an ethylene-vinyl acetate copolymer having a melt mass flow rate of 2.5 g/10 min or less under the conditions of 90:10 to 50:50 by mass fraction. provides a chlorine-based resin composition grafted with The chlorine-based resin composition having such a structure can be used as a coating material for electric wires and cables as an insulator or a sheath material.

In addition, a silane coupling agent having an unsaturated bond that reacts with radicals in its molecule has a relatively high flash point, and a methacrylic group-containing silane coupling agent is used as it has excellent fire safety when kneaded into a polymer. can be done. Examples of such silane coupling agents include 3-methacryloxypropyltrimethoxysilane and 3-methacryloxypropyltriethoxysilane.

Further, as a silanol condensation catalyst, an octyltin compound which is a tin-based compound with high catalytic ability and does not contain dibutyltin, which is considered to have a relatively large environmental load, can be used. Examples of such octyltin include dioctyltin dineodecanoate and dioctyltin dilaurate. Also. Since a small amount of the silanol condensation catalyst may be added to the chlorinated resin composition, it is useful to add the silanol condensation catalyst to the chlorinated resin composition as a high-concentration masterbatch from the viewpoint of quality stability and industrial aspects.

In addition, the chlorine-based resin composition of the present embodiment has a conductor cross-sectional area of 38 ^mm2 , which is the most severe condition of the abrasion test specified in the Electrical Appliance and Material Safety Law (Appended Table 1) and JISC3327 in multicore cables. It can be applied to wire and cable covering materials of various sizes.

<Method for preparing chlorine-based resin composition and cable>
The chlorine-based resin composition and the method for producing the cable are described below.

The kneading of silane and various additives into a mixture of chlorinated polyethylene and ethylene-vinyl acetate copolymer, the silane graft treatment, the production of a cable using the prepared compound, and the post-treatment can be carried out in the following order. The following conditions are examples and are not limited in any way.

(Kneading of silane and various additives)
Chlorinated polyethylene, ethylene-vinyl acetate copolymer, silane coupling agent, organic peroxide, hydrogen chloride scavenger, plasticizer, lubricant, reinforcement to a pressurized kneader with a capacity of 25 L (the temperature of the kneader tank is adjusted to 100°C) An agent, a filler and a flame retardant were added and kneaded under pressure for 10 minutes at a rotor speed of 10 rpm. Here, by dissolving the organic peroxide in the silane coupling agent in advance, the dispersibility of the organic peroxide in the polymer can be improved. In addition, adsorption of the silane coupling agent to the kneader vessel can be reduced by impregnating the filler such as the reinforcing agent with the silane coupling agent (organic peroxide dissolved) at the time of charging. Further, by adding the ethylene-vinyl acetate copolymer at the final stage of kneading, the viscosity of the material during kneading of the additive can be increased to improve the dispersibility. These conditions are examples and are not limited.

(Silane graft treatment)
After kneading, the material is kneaded and heated to 180° C. at a rotor rotation speed of 30 rpm using the same device (pressure kneader with a capacity of 25 L, the temperature of the kneader is adjusted to 100° C.). This operation can be performed continuously without discharging the material after the kneading. After reaching 180° C., the rotation speed is reduced and isothermal kneading is performed for 3 minutes and 30 seconds to dynamically graft the silane coupling agent to the polymer. After completion of grafting, the material is quickly discharged into a hopper of a single-screw extruder, extruded into a strand, cooled with water, and then pelletized to produce pellets of the chlorine-based resin composition. Here, the granulation method is not limited to the above. For example, pellets may be produced using hot-cut equipment without water cooling. A release agent can also be used to prevent the pellets from sticking together. The release agent may be in the form of powder, liquid, mist or the like, but it is effective to use talc or the like in consideration of economy.

(Preparation of master batch pellet)
A pressurized kneader with the same capacity of 25 L as the above (the temperature of the kneader tank is adjusted to 100 ° C.) is added with a polymer (a hydrogen chloride scavenger can also be used in the case of chlorine-based materials), an antioxidant, and a silanol condensation catalyst. It is put in and kneaded under pressure for 10 minutes at a rotation speed of 10 rpm. The polymer may be the same chlorinated polyethylene and ethylene-vinyl acetate copolymer as the main material, and is not particularly limited. The material after kneading is granulated into pellets in the same manner as in the above-mentioned silane grafting treatment, and a release agent may be used to prevent the pellets from sticking to each other.

(Cable manufacturing and cross-linking treatment)
A conductor having a cross-sectional area of 50 mm ² (outer diameter of 10.4 mm), which is made by twisting a plurality of tin-plated annealed copper wires, is coated with an ethylene-propylene rubber copolymer mixture as an insulator in a thickness of 1.5 mm by extrusion. Subsequently, a cable core obtained by twisting three crosslinked cores, a chlorine-based resin composition and masterbatch pellets dry-blended were extruded into a cable core having a thickness of 3.0 mm using a single screw extruder with a screw diameter of 90 mm. Cables are made by extrusion coating to 3 mm. Here, the finished outer diameter of the cable is about 36 mm. The cable after fabrication is crosslinked by being stored in a saturated steam atmosphere at 60° C. for 24 hours. That is, after the cable is coated, the silanes are bonded to each other (crosslinks are formed between polymer molecules) by the action of moisture and a silanol condensation catalyst. That is, the chlorine-based resin composition is crosslinked to form a silane crosslinked rubber composition. The dry blending performed here is to mix two or more kinds of pellets in a bag or a kettle manually or mechanically.

In order to achieve the above-described kneading and grafting treatment, generally used kneading and reaction devices such as roll machines, extruders, mixers and autoclapes can be used. Also, the kneading and grafting conditions are not limited to those described above. Similarly, the cable manufacturing method described above is merely an example, and the extruder, cable core, cable structure and cross-linking treatment conditions are not limited to those described above. Here, the use of the chlorine-based resin composition of the present embodiment as the sheath material in the production of the cable has been described, but the chlorine-based resin composition may also be used as the insulator, which is the covering material of the conductor. That is, the chlorine-based resin composition may be used for both the insulator forming the core and the sheath covering the core.

<Example>
Examples and comparative examples of the present embodiment will be described below with reference to FIGS. 1 and 2 and Tables 1 to 3.

The present inventors produced a chlorinated resin composition, a masterbatch and a cable using the equipment, cable structure, cable fabrication extrusion conditions and material formulation shown in FIGS. And about the cable which performed the Silang graft composition and the bridge|crosslinking process, the characteristic was evaluated as shown below.

The schematic diagram of FIG. 1 shows an extruder for producing cables used in the present embodiment and comparative examples. As shown in FIG. 1, the extruder 1 includes a cylinder 5, a screw 3 provided in the cylinder 5 so as to be able to rotate about its axis, a hopper 2 for supplying material into the cylinder 5, and a crosshead 7. . The extruder 1 also has a neck 6 between the crosshead 7 and the screw 3 and a breaker plate 4 between the neck 6 and the screw 3 . The crosshead 7 has a die 8, and the core 9 passing through the crosshead 7, that is, the conductor covered with an insulator, is covered with a sheath inside the crosshead 7, passes through the die 8, and passes through the die 8. It is pulled out from inside the crosshead 7 as a cable 10 .

FIG. 2 is a cross-sectional view showing a cable produced by the extruder 1. FIG. As shown in FIG. 2, the cable 10 is constructed by twisting three cores 9 and covering them with a sheath 13 . The core 9 consists of a conductor 11 with a cross-sectional area of 50 mm ² and an insulator 12 surrounding it. The insulator 12 is made of, for example, an ethylene-propylene rubber copolymer blend. The sheath 13 covers all three cores 9 .

A diameter of the 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 the core 9 and the outer peripheral surface of the sheath 13 is, for example, 3.3 mm.

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

Among the products shown in Tables 2 and 3, "CM3685" and "CM352L" are manufactured by Kali Chemical (China), "Eraslen 401A" is manufactured by Showa Denko, and "EV270", "EV460", "EV450" and "V5274" are manufactured. ” and “EV550” are manufactured by Mitsui Dow Polychemicals. In addition, among the products shown in Tables 2 and 3, "VF-120T" is manufactured by Ube Maruzen Polyethylene, "KBM-503" is manufactured by Shin-Etsu Chemical, "DCP" is manufactured by NOF, and "carbon black" is manufactured by Nippon Steel. HTC#S made of carbon (arithmetic mean particle size 68 nm).

Of these, CM3685 has a Mooney viscosity of 85, CM352L has a Mooney viscosity of 55, and Eraslen 401A has a Mooney viscosity of 115. EV270 has a melting point of 72° C. and a melt mass flow rate of 1 g/10 min. VF120T has a melting point of 85° C. and a melt mass flow rate of 1 g/10 min. EV460 has a melting point of 84° C. and a melt mass flow rate of 2.5 g/10 min. EV450 has a melting point of 84° C. and a melt mass flow rate of 15 g/10 min. V5274 has a melting point of 89° C. and a melt mass flow rate of 0.8 g/10 min. EV550 has a melting point of 89° C. and a melt mass flow rate of 15 g/10 min.

(1) Wear characteristics (wear resistance)
A test was carried out according to JISC3005 using the cable after the cross-linking treatment. The mass of the weight is 10 kg and the number of revolutions of the grindstone disc is 1000. After the test, if the insulator is not exposed, it is good. (Symbol notation x in Tables 2 and 3). In addition, for those where the insulator is not exposed, the depth of the worn portion is calculated from the following formula (1) using a micrometer. 2 to Table 3 symbol notation ◎).

Wear depth = Outer diameter of cable before test - Thickness of cable at worn part after test (1)
(2) Mooney viscosity (workability)
The Mooney viscosity at 130° C. (value after 4 minutes after preheating for 1 minute) was measured using the composition after the Silang graft treatment. It can be said that the lower the Mooney viscosity, the smaller the load during cable extrusion and the better the workability. In actual production, the lower the viscosity, the higher the discharge rate and the higher the cable extrusion speed. Furthermore, the lower the viscosity, the less the extrusion strain remains during high-speed extrusion, and there is an advantage that heat shrinkage can be suppressed after cable laying. Those with a Mooney viscosity of less than 60 were rated as good (symbols ◯ or ⊚ in Tables 2 and 3), and those with Mooney viscosities of 60 or more were considered unsatisfactory (symbols x in Tables 2 and 3). In addition, those having a Mooney viscosity of less than 50 were judged to have particularly excellent processability (symbol notation ⊚ in Tables 2 and 3).

(3) Comprehensive Judgment In the above (1) and (2), if both characteristics are good, pass (symbol notation 〇 or ◎ in Table 2 and Table 3). It was described as failure (symbol notation x in Tables 2 and 3).

From the examples, it was found that wear resistance improved with an increase in the amount of chlorinated polyethylene added, and workability improved with an increase in the amount of ethylene-vinyl acetate copolymer added. In addition, by adjusting the mixing mass ratio of chlorinated polyethylene and ethylene vinyl acetate copolymer to 90:10 to 50:50, both wear resistance and workability can be achieved, and further by adjusting the ratio to 70:30 It was found that excellent properties were obtained in both wear resistance and workability.

On the other hand, from Comparative Examples 1 and 2, it was found that when the addition ratio of chlorinated polyethylene was excessively increased, the workability was deteriorated, and when the addition ratio of the ethylene-vinyl acetate copolymer was excessively increased, the abrasion resistance was deteriorated. . Moreover, it was shown from Comparative Example 3 that if the Mooney viscosity of the chlorinated polyethylene itself is too low (too low the molecular weight), the abrasion resistance is lowered. Also, from Comparative Examples 4 to 6, it was confirmed that lowering the melting point of the ethylene-vinyl acetate copolymer or increasing the melt mass flow rate lowers the abrasion resistance.

In Comparative Example 3, CM352L has a Mooney viscosity of 85 or less (specifically, 55), so the abrasion resistance is determined to be poor. In Comparative Examples 5 and 6, since the melt mass flow rate of the ethylene-vinyl acetate copolymer was not 2.5 g/10 min or less, the wear resistance was determined to be poor.

From the above, in order to achieve both wear resistance and workability, in addition to the Mooney viscosity (molecular weight) of the chlorinated polyethylene itself, the melting point and melt mass flow rate of the ethylene-vinyl acetate copolymer, the mixing ratio of both materials is important. It has been found that the desired properties can be obtained by properly controlling these factors.

In the present embodiment, a chlorinated resin composition having good workability while satisfying wear resistance under severe conditions while using silane crosslinking, which is an energy-saving and highly economical cross-linking method for electric wires and cables. And it is possible to manufacture electric wires and cables coated with this.

The present invention is not limited to the above-described embodiments and examples, and various modifications can be made without departing from the scope of the invention.

1 Extruder 2 Hopper 3 Screw 5 Cylinder 8 Die 9 Core 10 Cable

Claims (14)

A chlorinated polyethylene having a Mooney viscosity of 85 or more after 4 minutes of preheating at 121°C for 1 minute, and a melt mass flow rate of 2.5 g/10 min or less at 190°C and 2.16 kgf, and A chlorine-based resin composition comprising a base polymer mixed with an ethylene-vinyl acetate copolymer having a melting point of 80° C. or higher in a mass fraction range of 90:10 to 50:50, and a silane coupling agent grafted thereto. thing. In the chlorine-based resin composition according to claim 1,
A chlorinated resin composition to which a silanol condensation catalyst is added and crosslinked by the action of moisture. In the chlorine-based resin composition according to claim 2,
The chlorine-based resin composition, wherein the silanol condensation catalyst is an octyltin compound and is added to the chlorine-based resin composition as a masterbatch mixed with a polymer. In the chlorine-based resin composition according to claim 1 or 2,
The silane coupling agent is a chlorine-based resin composition containing a methacrylic group as an organic functional group. a conductor;
an insulator covering the conductor;
has
The insulating material includes chlorinated polyethylene having a Mooney viscosity of 85 or more after 4 minutes of preheating at 121°C and a melt mass flow rate of 2.5 g/10 min or less at 190°C and 2.16 kgf. and an ethylene-vinyl acetate copolymer having a melting point of 80° C. or higher and a base polymer mixed in a mass fraction range of 90:10 to 50:50, to which a silane coupling agent was grafted. Consisting of a chlorine-based resin composition,
The electric wire, wherein the chlorine-based resin composition is crosslinked by the action of moisture. In the electric wire according to claim 5,
The electric wire, wherein the chlorine-based resin composition is added with a silanol condensation catalyst and crosslinked by the action of moisture. In the electric wire according to claim 6,
The electric wire, wherein the silanol condensation catalyst is an octyltin compound and is added to the chlorine-based resin composition as a masterbatch mixed with a polymer. In the electric wire according to claim 5 or 6,
The electric wire, wherein the silane coupling agent contains a methacrylic group as an organic functional group. In the electric wire according to any one of claims 5 to 8,
The electric wire, wherein the conductor has a cross-sectional area greater than 38 mm ² . an electric wire including a conductor and an insulating material covering the conductor;
a covering material for covering the electric wire;
has
The coating material consists of chlorinated polyethylene having a Mooney viscosity of 85 or more after 4 minutes of preheating at 121° C. and a melt mass flow rate of 2.5 g/10 min or less at 190° C. and 2.16 kgf. and an ethylene-vinyl acetate copolymer having a melting point of 80° C. or higher and a base polymer mixed in a mass fraction range of 90:10 to 50:50, to which a silane coupling agent was grafted. Consisting of a chlorine-based resin composition,
The cable, wherein the chlorine-based resin composition is crosslinked by the action of moisture. A cable according to claim 10, wherein
The cable, wherein the chlorine-based resin composition is added with a silanol condensation catalyst and crosslinked by the action of moisture. A cable according to claim 11, wherein
The cable, wherein the silanol condensation catalyst is an octyltin compound and is added to the chlorine-based resin composition as a masterbatch mixed with a polymer. In the cable according to claim 10 or 11,
The cable, wherein the silane coupling agent contains a methacrylic group as an organic functional group. In the cable according to any one of claims 10 to 13,
The cable, wherein the conductor has a cross-sectional area greater than 38 mm ² .

Images