JP6424767B2 - Insulated wire and cable - Google Patents

Description

  The present invention relates to an insulated wire and a cable.

  A coating layer (an insulating layer, a sheath, etc.) is provided on the surface of the insulated wire or cable. The coating material which forms a coating layer changes with uses of an insulated wire or a cable, and when flexibility is especially required, a rubber material is used. As such a rubber material, there is a chlorine-based polymer, and among them, chlorinated polyethylene is used because of its excellent mechanical properties and oil resistance.

  Generally, when forming a coating layer using a rubber material, the coating material is subjected to a crosslinking treatment in order to develop rubber elasticity and heat resistance in the coating layer. As the crosslinking treatment, for example, silane crosslinking using a silane compound (so-called silane coupling agent) is widely performed (see, for example, Patent Document 1).

  Specifically, the coating layer is formed by silane crosslinking as follows. That is, first, a silane compound is added to chlorinated polyethylene which is a rubber material, and graft copolymerization is carried out to prepare silane-grafted chlorinated polyethylene. Subsequently, the silane-grafted chlorinated polyethylene is extruded to form a coating layer, and then the coating layer is silane crosslinked by exposure to moisture.

Japanese Patent Publication No. 50-35540

  However, in the insulated wire or cable, when the coating layer is subjected to silane crosslinking, the coating layer may be deformed. In general, silane crosslinking of the coating layer is carried out by exposing the rubber material to a drum shape after extruding a rubber material and winding the uncrosslinked insulated wire or cable in a drum shape. Therefore, the uncrosslinked coating layer is crushed and deformed by its own weight or tension of a cable or the like before it develops rubber elasticity by crosslinking. As a result, the coating layer is silane-crosslinked in a deformed state, and the appearance of the surface is impaired.

  In addition, the coating layer is required to be excellent in oil resistance without being easily deteriorated by contact with an engine oil or the like in the use environment of the insulated wire or cable.

  The present invention is made in view of the above-mentioned subject, and when chlorinated polyethylene is used for a covering layer, while controlling modification of a covering layer, it aims at providing art which maintains oil resistance highly. I assume.

According to one aspect of the invention:
With a conductor,
And an insulating layer disposed on the outer periphery of the conductor,
The insulating layer has a laminated structure including an inner layer and an outer layer,
The inner layer comprises an inner layer material containing a silane-grafted chlorine-based polymer (A) in which a silane compound is graft-copolymerized to the chlorine-based polymer (a),
The outer layer is a silane-grafted chlorinated polyethylene (B) in which a silane compound is graft-copolymerized on a chlorinated polyethylene (b), and a silane-grafted polyethylene (C) in which a silane compound is graft-copolymerized on polyethylene (c); Consists of outer layer material including
An insulated wire is provided, wherein the inner layer and the outer layer are configured to be integrally silane cross-linked.

According to another aspect of the invention,
A conductor, an insulating layer disposed on the outer periphery of the conductor, and a sheath disposed on the outer periphery of the insulating layer,
The sheath has a laminated structure including an inner layer and an outer layer,
The inner layer comprises an inner layer material containing a silane-grafted chlorine-based polymer (A) in which a silane compound is graft-copolymerized to the chlorine-based polymer (a),
The outer layer is a silane-grafted chlorinated polyethylene (B) in which a silane compound is graft-copolymerized on a chlorinated polyethylene (b), and a silane-grafted polyethylene (C) in which a silane compound is graft-copolymerized on polyethylene (c); Consists of outer layer material including
A cable is provided, wherein the inner layer and the outer layer are integrally silane cross-linked.

  According to the present invention, when chlorinated polyethylene is used for the coating layer, deformation of the coating layer can be suppressed and oil resistance can be maintained high.

FIG. 1 is a schematic view of a cross section of a cable according to an embodiment of the present invention. It is the schematic for demonstrating the grafting process using the single screw extruder in an Example. It is the schematic for demonstrating preparation of the cable in an Example.

  According to the study of the present inventors, it has been found that it is better to mix plastic materials in order to suppress deformation before silane crosslinking in chlorinated polyethylene which is a rubber material. Plastic materials generally have a large amount of crystalline components (high crystallinity) and a high melting point as compared with rubber materials, and therefore they are not easily deformed even when they are not crosslinked. Therefore, by mixing the plastic material with the rubber material, the hardness can be increased and the deformation resistance can be improved.

  Furthermore, when the present inventors examined the plastic material, they found that polyethylene is preferable among the plastic materials. Polyethylene can graft-copolymerize a silane compound in the same manner as chlorinated polyethylene, and can be silane-crosslinked. That is, by mixing silane-grafted polyethylene with silane-grafted chlorinated polyethylene and reacting with water, these can be integrally silane-crosslinked. Therefore, according to polyethylene, even when mixed with chlorinated polyethylene, it is possible to obtain the same degree of crosslinking as when only chlorinated polyethylene is crosslinked with silane, without reducing the degree of crosslinking of the mixture.

  However, since polyethylene does not have a polar group, it has a problem that oil resistance is inferior to chlorinated polyethylene. That is, by mixing polyethylene with chlorinated polyethylene and performing silane crosslinking, while deformation of the coating layer can be suppressed, it becomes difficult to maintain high oil resistance. Although it is also conceivable to adjust the mixing ratio of polyethylene, it is difficult to achieve both of the deformation resistance and the oil resistance at a high level.

  Then, it examined by making a coating layer into a multilayer structure and thinly coating the outer layer with the mixed material containing silane grafting chlorinated polyethylene and silane graft polyethylene. As a result, it is possible to suppress the decrease in oil resistance by reducing the ratio of polyethylene occupied in the coating layer while maintaining high deformation resistance of the entire coating layer by the outer layer having excellent deformation resistance, and in the coating layer It has been found that high levels of deformation resistance and oil resistance are obtained.

  In addition, as for the inner layer of the covering layer, it was found that a material having high compatibility with the mixed material of the outer layer is preferable from the viewpoint of adhesion with the outer layer, and among them, a chlorine-based polymer is preferable. In addition, it was found that by extruding each of the inner layer and the outer layer and simultaneously performing silane crosslinking, it is possible to express a crosslinking reaction between these layers and integrally silane crosslink, and to greatly improve the adhesion.

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

One Embodiment of the Present Invention
Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic view of a cross section of a cable according to an embodiment of the present invention.

<Schematic Configuration of Cable>
As shown in FIG. 1, the cable 1 of the present embodiment includes a conductor 11, an insulating layer 12, and a sheath 13, and the sheath 13 has a laminated structure including an inner layer 14 and an outer layer 15.

(Conductor 11)
As the conductor 11, a copper wire made of low oxygen copper or oxygen free copper or the like, a copper alloy wire, a metal wire made of aluminum, silver or the like, or a stranded wire obtained by twisting metal wires can be used. The outer diameter of the conductor 11 can be appropriately changed according to the application of the cable 1.

(Insulating layer 12)
An insulating layer 12 is provided to cover the outer periphery of the conductor 11. The insulating layer 12 is formed of a conventionally known resin composition, for example, a resin composition containing an ethylene-propylene rubber. The thickness of the insulating layer 12 can be appropriately changed according to the application of the cable 1.

(Sheath 13)
A sheath 13 is provided to cover the outer periphery of the insulating layer 12. The sheath 13 has an inner layer 14 located on the conductor 11 side and an outer layer 15 located on the surface side. The inner layer 14 is made of an inner layer material containing a silane-grafted chlorine polymer (A), the outer layer 15 is made of an outer layer material containing a silane-grafted chlorinated polyethylene (B) and a silane-grafted polyethylene (C), and the sheath 13 is an inner layer After laminating and extruding the material and the outer layer material, the inner layer 14 and the outer layer 15 are configured to be integrally silane crosslinked by being simultaneously formed by silane crosslinking. Hereinafter, each of the inner layer 14 and the outer layer 15 will be described in detail.

(Inner layer 14)
The inner layer 14 is formed by subjecting the inner layer material containing the silane-grafted chlorine-based polymer (A) to silane crosslinking. Since the inner layer material contains the silane-grafted chlorine-based polymer (A), the inner layer material is excellent in compatibility with the outer layer material to which the silane compound is graft copolymerized. Therefore, the inner layer 14 is excellent in adhesion to the outer layer 15. Moreover, in the present embodiment, since the inner layer 14 and the outer layer 15 are configured to be integrally silane-crosslinked, the adhesion becomes higher. Moreover, since the inner layer 14 contains the silane graft chlorine-based polymer (A) which has a polar group, it contributes to the improvement of the oil resistance of the sheath 13 whole.

  The inner layer material comprises a silane grafted chlorine based polymer (A).

  The silane-grafted chlorine-based polymer (A) is obtained by graft-copolymerizing a silane compound on a chlorine-based polymer (a) using a peroxide. The silane-grafted chlorine-based polymer (A) has a silane group derived from a silane compound in the molecular chain, and forms a crosslinked body by silane crosslinking by reaction with water.

  The chlorinated polymer (a) is not particularly limited as long as it is excellent in compatibility with the material forming the outer layer 15 and has desired oil resistance, but at least at least chlorinated polyethylene, chloroprene rubber and chlorosulfonated polyethylene. One is preferred. These components contain chlorine in the molecular structure and are excellent not only in compatibility with the outer layer material forming the outer layer 15 but also in oil resistance because of their polarity.

The silane compound has an unsaturated bondable group and a hydrolyzable silane group. The silane compound is graft copolymerized to the chlorine-based polymer by radicals generated by the decomposition of the peroxide, thereby introducing a silane group into the chlorine-based polymer (a).
The unsaturated bond group is not limited as long as it can graft-polymerize a silane compound to a chlorine-based polymer (a), and examples thereof include a vinyl group, a methacrylic group and an acrylic group. Among these, methacryl group is preferable. The silane compound having a methacryl group (methacryl silane) has good compatibility with a chlorine-based polymer, and can uniformly introduce a crosslinked structure into the chlorine-based polymer.
As a hydrolyzable silane group, what has hydrolysable structures, such as a halogen, an alkoxy group, an acyloxy group, a phenoxy group, is mentioned, for example. As a silane group which has these hydrolysable structures, a halo silyl group, an alkoxy silyl group, an acyloxy silyl group, a phenoxy silyl group etc. are mentioned, for example.

  Specifically as methacryl silane, 3-methacryloxypropyl trimethoxysilane, 3-methacryloxy propyl triethoxysilane, etc. are preferable, and these may be used independently and may be used together.

  The amount of the silane compound to be graft-copolymerized to the chlorine-based polymer (a) may be appropriately changed depending on the degree of crosslinking of the inner layer 14 or the reaction conditions (eg, temperature, time, etc.) for crosslinking. Specifically, the compounding amount of the silane compound is preferably 0.1 parts by mass to 10 parts by mass with respect to 100 parts by mass of the chlorine-based polymer (a), and is 1.0 parts by mass to 5.0 parts by mass. It is more preferable that it is less than 1 part. If the amount is less than the above range, a sufficient degree of crosslinking may not be obtained when silane crosslinking is performed. On the other hand, if the amount is larger than the above range, premature crosslinking occurs before silane crosslinking, and in the inner layer 14, foreign matter (tubs) is formed due to crosslinking, which may result in poor appearance.

  The peroxide is not particularly limited as long as it can graft copolymerize a silane compound to the chlorine-based polymer (a). As the peroxide, specifically, dicumyl peroxide, 1,1-di (t-butylperoxy) cyclohexane, t-butylperoxyisopropyl carbonate, t-amyl peroxyisopropyl carbonate, 2,5 dimethyl 2,5 di (t-butylperoxy) hexane, di-t-butyl peroxide, di-t-amyl peroxide, 1,1-di (t-amylperoxy) cyclohexane, t-butylperoxy 2- Ethyl hexyl carbonate etc. can be used. One of these may be used alone, or two or more may be used in combination.

  In the inner layer material, a peroxide and a silane compound are added to the chlorine-based polymer (a), and the silane compound is graft copolymerized to the chlorine-based polymer (a) in the presence of the peroxide by heating and kneading. . Thus, a silane-grafted chlorine-based polymer (A) is formed to prepare an inner layer material.

(Outer layer 15)
The outer layer 15 is formed by silane crosslinking an outer layer material containing silane-grafted chlorinated polyethylene (B) and silane-grafted polyethylene (C). The outer layer material is obtained by graft copolymerization of a silane compound and is excellent in compatibility with the inner layer resin composition. Therefore, the outer layer 15 is excellent in adhesion to the inner layer 14. Moreover, in the present embodiment, since the inner layer 14 and the outer layer 15 are configured to be integrally silane-crosslinked, the adhesion becomes higher. Further, the outer layer material contains silane-grafted polyethylene (C) having high crystallinity and high hardness, and since it is excellent in deformation resistance even in the uncrosslinked state, the outer layer 15 made of it has little deformation such as crushing and has a good appearance It is. Furthermore, although the outer layer 15 contains silane-grafted polyethylene (C) and tends to have low oil resistance, in the present embodiment, the outer layer 15 is configured as a part of the laminated structure of the sheath 13 to reduce the ratio of the sheath 13 Therefore, the desired high oil resistance can be obtained without significantly reducing the oil resistance of the entire sheath 13.

  Outer layer materials include silane grafted chlorinated polyethylene (B) and silane grafted polyethylene (C).

The silane graft chlorinated polyethylene (B) is obtained by graft copolymerization of a silane compound with chlorinated polyethylene (b) using a peroxide, and mainly contributes to the improvement of the oil resistance of the outer layer 15.
Chlorinated polyethylene (b) is obtained, for example, by blowing chlorine gas into an aqueous suspension obtained by suspending and dispersing linear polyethylene (such as low density polyethylene and high density polyethylene) in water. The degree of chlorination of the chlorinated polyethylene (b) is not particularly limited, but from the viewpoint of making the degree of grafting of the silane compound and the degree of crosslinking when crosslinked into a desired range, for example, 25% or more and 45% or less Is preferable, and more preferably 30% or more and 40% or less.
As a silane compound which carries out graft polymerization to chlorinated polyethylene (b), what was mentioned above can be used, and a silane compound (methacryl silane) which has methacryl group is preferred.
As the peroxide, those described above can be used.

  The amount of the silane compound to be graft-copolymerized to the chlorinated polyethylene (b) may be appropriately changed depending on the degree of crosslinking of the outer layer 15 or the reaction conditions (eg, temperature, time, etc.) for crosslinking. In the outer layer 15, from the viewpoint of obtaining a high degree of crosslinking when silane crosslinking is performed and suppressing appearance defects due to premature crosslinking, the compounding amount of the silane compound is 0.1 parts by mass with respect to 100 parts by mass of chlorinated polyethylene. The content is preferably 10 parts by mass or less and more preferably 1.0 parts by mass or more and 5.0 parts by mass or less.

Silane-grafted polyethylene (C) is obtained by graft-copolymerizing a silane compound to polyethylene (c) using a peroxide to increase the hardness of the outer layer material and improve the deformation resistance in an uncrosslinked state .
The polyethylene (c) is not particularly limited as long as it can graft-polymerize a silane compound, and for example, high density polyethylene (HDPE), low density polyethylene (LDPE), linear low density polyethylene (LLDPE), etc. It can be used. From the viewpoint of further improving the deformation resistance of the outer layer material in the uncrosslinked state, it is preferable to use a polyethylene (c) having a high density. This is because the higher the density of polyethylene (c), the more crystal components, and the higher the hardness. Specifically, the density is preferably 0.90 g / ml or more. On the other hand, if the density is too high, the hardness of the outer layer material becomes excessively high, and the flexibility of the sheath 13 may be impaired. Therefore, the upper limit value of the density is preferably 0.95 g / ml or less.
As a silane compound which carries out graft polymerization to polyethylene (c), what was mentioned above can be used and a silane compound (methacryl silane) which has methacryl group is preferred.
As the peroxide, those described above can be used.

  The amount of the silane compound to be graft-copolymerized to the polyethylene (c) may be appropriately changed depending on the degree of crosslinking of the outer layer 15 or the reaction conditions (eg, temperature, time, etc.) at the time of crosslinking. In the outer layer 15, from the viewpoint of obtaining a high degree of crosslinking when silane crosslinking is performed and suppressing appearance defects due to premature crosslinking, the compounding amount of the silane compound is 0.1 mass to 100 mass parts of polyethylene (c) The content is preferably not less than 5 parts by mass and more preferably not less than 1.0 parts by mass and not more than 3.0 parts by mass.

  The outer layer material includes silane-grafted chlorinated polyethylene (B) and silane-grafted polyethylene (C), but the mixing ratio thereof is not particularly limited. When the mixing ratio of the silane-grafted polyethylene (C) increases, the deformation resistance of the outer layer material increases while the oil resistance of the outer layer 15 decreases, so from the viewpoint of obtaining a good balance of deformation resistance and oil resistance, It is preferable that the ratio of silane graft chlorinated polyethylene (B) and silane graft polyethylene (C) will be 55: 45-90: 10 by mass ratio.

  The thickness of the outer layer 15 is not particularly limited, but is preferably at least 0.2 mm or more from the viewpoint of suppressing deformation of the non-crosslinked outer layer material when the outer layer 15 is formed. On the other hand, when the thickness of the outer layer 15 becomes excessively large, the ratio occupied in the sheath 13 becomes high, and there is a possibility that the oil resistance of the sheath 13 as a whole becomes low, so it is preferably 1.0 mm or less.

  The outer layer material is obtained by graft copolymerizing a silane compound to each of chlorinated polyethylene (b) and polyethylene (c), and then mixing silane-grafted chlorinated polyethylene (B) and silane-grafted polyethylene (C). It is preferred to prepare. Thereby, a silane compound can be graft-copolymerized on conditions respectively optimal to (b) component and (c) component. The grafting reaction conditions (temperature, time, etc.) at this time are not particularly limited.

  In addition, you may mix | blend a silanol condensation catalyst with outer layer material and inner layer material as needed. According to the silanol condensation catalyst, the reaction of silane crosslinking can be promoted to effect crosslinking efficiently.

  As the silanol condensation catalyst, for example, Group II elements such as magnesium and calcium, Group VIII elements such as cobalt and iron, metal elements such as tin, zinc and titanium, and metal compounds containing these elements can be used. In addition, metal salts of octylic acid and adipic acid, amine compounds, acids and the like can be used. Specifically, as metal salts, dioctyltin dineodecanoate, dibutyltin dilaurate, dibutyltin diacetate, dibutyltin dioctaate, stannous acetate, stannous carboxylate, lead naphthenate, zinc caprylate, naphthene Acid cobalt and the like can be used. As the amine compound, ethylamine, dibutylamine, hexylamine, pyridine and the like can be used. As the acid, an inorganic acid such as sulfuric acid or hydrochloric acid, or an organic acid such as toluenesulfonic acid, acetic acid, stearic acid or maleic acid can be used.

  In addition, the outer layer material and the inner layer material include plasticizers, antioxidants (including anti-aging agents), fillers such as carbon black, flame retardants, lubricants, anti-copper discoloration inhibitors, cross-linking assistants, stabilizers, etc. Other additives may be blended.

  In addition, in the kneading operation such as graft copolymerization of the silane compound, for example, it is preferable to knead using a kneading reaction device such as a roll machine, an extruder, a kneader, a mixer, an autoclave or the like.

  The types of silane compounds to be graft-copolymerized to the chlorinated polymer (a), the chlorinated polyethylene (b) and the polyethylene (c) may be the same or different.

<Method of manufacturing cable>
The method of manufacturing the cable 1 of the present embodiment includes an insulating layer forming step of forming the insulating layer 12 on the outer periphery of the conductor 11, and an extrusion step of laminating and extruding the inner layer material and the outer layer material on the outer periphery of the insulating layer 12; And a crosslinking step in which the inner layer material and the outer layer material are exposed to moisture and simultaneously silane crosslinked.

  First, for example, ethylene propylene rubber is extruded and coated on the outer periphery of the conductor 11 to form the insulating layer 12.

  Subsequently, the inner layer material and the outer layer material are extruded and coated in this order on the outer periphery of the insulating layer 12.

  Subsequently, the extruded inner layer material and outer layer material are exposed to moisture, for example, exposed to the atmosphere. Thereby, the silane group in each molecular chain becomes a silanol group by hydrolysis, and the (A) component contained in inner layer material and the (B) component and (C) component contained in outer layer material become these silanol groups, Silane crosslinking is carried out by dehydration condensation to form a crosslinked structure. The silane crosslinking occurs not only in each of the inner layer material and the outer layer material but also in these layers, so that in the sheath 13, the inner layer 14 and the outer layer 15 are integrally silane crosslinked.

  The cable 1 of this embodiment is obtained by the above.

Another Embodiment of the Present Invention
As mentioned above, although one Embodiment of this invention was described concretely, this invention is not limited to the above-mentioned embodiment, It can change suitably in the range which does not deviate from the summary.

  In the above-mentioned embodiment, after extruding the inner layer material and the outer layer material on the outer periphery of the insulating layer 12, the case where they are simultaneously silane-crosslinked has been described, but the present invention is not limited thereto. For example, after the inner layer material is extruded and silane cross-linked to form the inner layer 14, the outer layer material may be extruded on the outer periphery of the inner layer 14 and silane cross-linked to form the outer layer 15. In this case, when the outer layer material extruded on the outer periphery of the inner layer 14 is silane-crosslinked, silane crosslinking proceeds between the inner layer 14 and the outer layer material, and high adhesion is obtained between the inner layer 14 and the outer layer 15. Be

  Although the above-mentioned embodiment explained the case where cable 1 provided with one insulated wire by which insulating layer 12 was provided in the perimeter of conductor 11, cable 1 twisted two or more insulated wires. A line may be provided.

  Although the above-mentioned embodiment demonstrated the case where sheath 13 was made into the layered structure which has inner layer 14 and outer layer 15 in cable 1, the present invention is not limited to this. For example, in the insulated wire in which the insulating layer is formed on the outer periphery of the conductor, the insulating layer may have a laminated structure having an inner layer and an outer layer.

  Next, the present invention will be described more specifically using examples. The present invention is not limited by the following examples.

  The following materials were used in the examples and comparative examples.

The following was used as a polymer component.
Chlorinated polyethylene (Mooney viscosity (ML _{1 + 4} ): 55): “CM 352 L” manufactured by Hangzhou Chemical Industrial Co., Ltd.
・ Chloroprene rubber (non-vulcanized modified type, Mooney viscosity (ML _{1 + 4} ): 48): Showpred Co., Ltd. “Shaprene W”
Low density polyethylene (density d: 0.922 g / ml, MFR: 2.3 g / 10 min): "Evolue SP2030" manufactured by Prime Polymer Co., Ltd.

The following were used as a silane compound.
-3-methacryloxypropyl trimethoxysilane: "KBM-503" manufactured by Shin-Etsu Chemical Co., Ltd.
-Vinyltrimethoxysilane: "KBM-1003" manufactured by Shin-Etsu Chemical Co., Ltd.
3-Aminopropyltrimethoxysilane: "KBM-903" manufactured by Shin-Etsu Chemical Co., Ltd.

The following was used as a peroxide.
Dicumyl peroxide: Nippon Oil and Fats Co., Ltd. “DCP”

The following were used as other additives.
Stabilizer (hydrotalcite): "Mag Celler 1" manufactured by Kyowa Chemical Industry Co., Ltd.
Stabilizer (epoxidized soybean oil): "Newsizer 510R" manufactured by NOF Corporation
・ Stabilizer (magnesium oxide): Kyowa Chemical Industry Co., Ltd. "Kyowamag 30"
-Lubricant (polyethylene wax): Mitsui Chemicals, Inc. "High Wax NL 200"
・ Plasticizer (naphthene process oil): "NP-24" manufactured by Idemitsu Kosan Co., Ltd.
Carbon (FEF carbon black): "Asahi Carbon 60G" manufactured by Asahi Carbon Co., Ltd.
・ Flame retardant (antimony trioxide): Sumitomo Metal Mining Co., Ltd. "antimony trioxide"
・ Antioxidant (4,4'-thiobis (3-methyl-6-tert-butylphenol)): "NOCLAK 300R" manufactured by Ouchi Shinko Chemical Co., Ltd.
・ Antioxidant (2,2,4-trimethyl-1,2-dihydroquinoline polymer): Nocchi 224 manufactured by Ouchi Shinko Chemical Co., Ltd.
· Silanol condensation catalyst (dioctyltin dineodecanoate): "Neostan U-830" manufactured by Nitto Kagaku Co., Ltd.

  First, silane graft materials A to D for preparing the inner layer material and the outer layer material, and a catalyst master batch were prepared with the formulations shown in Table 1 below.

(Preparation of Silane Grafting Material A)
A composition containing silane-grafted chlorinated polyethylene as silane-grafted material A was prepared.
First, as shown in Table 1, 6 parts by mass of hydrotalcite, 6 parts by mass of epoxidized soybean oil and 3 parts by mass of polyethylene wax with respect to 100 parts by mass of powdered chlorinated polyethylene Add and knead using an 8-inch roll machine. At this time, the surface temperature of the roll was 100 ° C., and the kneading time was 5 minutes after the addition of stabilizers and the like. Thereafter, the sheet obtained by kneading was pelletized into a 5 mm square shape to obtain pellets containing chlorinated polyethylene. The pellet was dusted with 1 part by mass of talc to prevent adhesion between the pellets.

Subsequently, the obtained pellet was subjected to a grafting treatment.
Specifically, the obtained pellet was sufficiently impregnated with a silane mixture in which a peroxide was dissolved in a silane compound. At this time, as shown in Table 1, the silane mixture in the pellet is such that the peroxide is 0.5 parts by mass and the methacrylsilane (KBM-503) is 5 parts by mass with respect to 100 parts by mass of the chlorinated polyethylene. Was impregnated. Then, the pellet impregnated with the silane mixture was introduced from the hopper 101 of the single-screw extruder 100 shown in FIG. 2 into the cylinder 103a, and was delivered from the cylinder 103a to the cylinder 103b by the rotation of the screw 102. At this time, the pellets were subjected to softening polymerization by heating in cylinders 103a and 103b, thereby graft polymerizing the silane compound to chlorinated polyethylene. This formed a silane grafted chlorinated polyethylene. Thereafter, the silane graft chlorinated polyethylene was delivered to the head portion 104 of the extruder 100, and the strand 20 (150 cm in length) of the silane graft chlorinated polyethylene was extruded from the die 105. Then, the strand 20 was introduced into the water tank 106, water-cooled, and drained by the air wiper 107. Thereafter, the strands 20 were pelletized by a pelletizer 108 to obtain pellets containing silane-grafted chlorinated polyethylene.
In the grafting process, a single-screw extruder 100 with a screw diameter of 40 mm was used. Further, the ratio L / D of the screw diameter D to the screw length L was set to 25. Further, the temperature of the cylinder 103a is 80 ° C., the temperature of the cylinder 103 b is 200 ° C., the temperature of the head portion 104 is 200 ° C., and the temperature of the die 105 is 200 ° C. In addition, the rotation speed of the screw 102 is 20 rpm (the extrusion amount is about 120 g / min), and the screw 102 is in a full flight shape. Further, as the die 105, a die having a hole diameter of 5 mm and a hole number of 3 was used.

  Subsequently, plasticizers, antioxidants, carbon black, flame retardants and lubricants were added to the pellets containing silane-grafted chlorinated polyethylene in the formulations shown in Table 1 and kneaded using an 8-inch roll machine. At this time, the surface temperature of the roll was 100 ° C., and the kneading time was 5 minutes after the addition of stabilizers and the like. Thus, a silane graft material A was prepared.

(Preparation of silane graft material B)
In the silane graft material B, the type of silane compound is changed from methacryl silane to vinyl silane (KBM-1003) and the blending amount of peroxide is appropriately changed to form a silane graft chlorinated polyethylene in which vinyl silane is graft copolymerized. It was prepared in the same manner as the silane graft material A except for the above.

(Preparation of Composition C)
A composition containing silane-grafted chloroprene rubber as silane-grafted material C was prepared.
Specifically, materials other than a silane compound were added to chloroprene rubber and kneaded using an 8-inch roll machine. At this time, the surface temperature of the roll was 80 ° C., and the kneading time was 5 minutes after the addition of the stabilizer and the like. Thereafter, the sheet obtained by kneading is pelletized into a shape of 5 mm square to obtain pellets containing chloroprene rubber. The pellet was dusted with 1 part by mass of talc to prevent adhesion between the pellets.
The pellets were impregnated with a silane compound, and graft treated under the same conditions as the silane graft material A to form a silane graft chloroprene rubber, thereby preparing a silane graft material C.

(Preparation of silane graft material D)
As a silane graft material D, a composition containing silane-grafted polyethylene was prepared.
Specifically, polyethylene pellets were fully impregnated with the silane mixture. At this time, as shown in Table 1 below, silane is added to the pellet such that the peroxide is 0.1 parts by mass and the silane compound (KBM-1003) is 1.5 parts by mass with respect to 100 parts by mass of polyethylene. The mixture was impregnated. Then, the pellets impregnated with the silane mixture are charged into the single-screw extruder 100 shown in FIG. 2 and grafting is performed to form a silane-grafted polyethylene, and the strands are pelletized to contain the silane-grafted polyethylene. Composition D was prepared.
In the grafting process, a single-screw extruder 100 with a screw diameter of 40 mm was used. Further, the ratio L / D of the screw diameter D to the screw length L was set to 25. Further, the temperature of the cylinder 103 a was 80 ° C., the temperature of the cylinder 103 b was 200 ° C., and the temperature of the head portion 104 was 200 ° C. In addition, the rotation speed of the screw 102 is 20 rpm (the extrusion amount is about 120 g / min), and the screw 102 is in a full flight shape. Further, as the die 105, a die having a hole diameter of 5 mm and a hole number of 3 was used.

(Preparation of catalyst masterbatch)
Subsequently, separately from the above-mentioned compositions A to D, a catalyst masterbatch containing a silanol condensation catalyst was prepared.
Specifically, with respect to 100 parts by mass of powdered chlorinated polyethylene, 6 parts by mass of hydrotalcite, 6 parts by mass of epoxidized soybean oil, 3 parts by mass of polyethylene wax, and a silanol condensation catalyst 2 parts by mass of dioctyltin dineodecanoate as was added and kneaded using an 8-inch roll machine. At this time, the surface temperature of the roll was set to 100 ° C., and the silanol condensation catalyst was added, and the mixture was kneaded for 3 minutes. Then, the sheet | seat which consists of kneading | mixing materials was pelletized in the shape of 5 mm square, and the catalyst masterbatch was prepared.

(Preparation of material for chemical crosslinking)
As a comparative material, a composition for chemical crosslinking with peroxide rather than silane crosslinking was prepared.
Specifically, in the preparation of the silane graft material A, a material for chemical crosslinking was prepared by kneading the components other than the silane compound without adding the silane compound and performing the grafting treatment.

Example 1
(1) Preparation of inner layer material and outer layer material First, as shown in Table 2 below, an inner layer material was prepared by adding a catalyst master batch to silane graft material A containing silane-grafted chlorinated polyethylene and dry blending it. . In addition, the addition amount of the catalyst masterbatch was 1/20 mass part with respect to the chlorinated polyethylene of the silane grafting material A.
In addition, a weight ratio of 105.48: Silane graft material A containing silane graft chlorinated polyethylene and Silane graft material C containing silane graft polyethylene, such that the ratio of chlorinated polyethylene to polyethylene is 60:40: The outer layer material was prepared by mixing at 40.64.

(2) Production of Cable Next, a cable was produced using the inner layer material and the outer layer material prepared above.
Specifically, an EP rubber insulator core (conductor cross-sectional area) in which an insulating layer 12 made of ethylene propylene rubber (EP rubber) is formed on the surface of a conductor 11 using a single-screw extruder 100 as shown in FIG. The outer layer material is extruded to have a thickness of 0.5 mm after extruding the inner layer material to a thickness of 1.5 mm on the outer periphery of 8 mm ² , a rubber insulator thickness of 1 mm, and an outer diameter of 3.7 mm. It was extrusion coated. Thereafter, the cable 1 including the sheath 13 having the inner layer 14 and the outer layer 15 is produced by storing the inner layer material and the outer layer material by silane crosslinking by storing in a constant temperature and humidity chamber having a temperature of 60 ° C. and a relative humidity of 95% for 24 hours. did.
In the production of the cable 1, a single-screw extruder with a screw diameter of 75 mm and a ratio L / D20 for the extrusion of the inner layer material and a single-screw extruder with a screw diameter of 40 mm and a ratio L / D20 for the extrusion of the outer layer material Each was used.
Moreover, the extrusion conditions of the silane grafting chlorinated polyethylene which is an inner-layer material were made as follows. The temperature of the cylinder 103a to the cylinder 103b is 100 ° C-110 ° C-115 ° C-120 ° C-130 ° C, the temperature of the neck 109 is 130 ° C, the temperature of the crosshead 110 is 130 ° C, and the temperature of the die 105 is 130 ° C. . The rotational speed of the screw 102 was 15 rpm, and the shape of the screw 102 was a full flight shape. The take-up speed of the cable 1 was 10 m / min.
The extrusion conditions of the outer layer material were as follows. The temperature of the cylinder 103 a to the cylinder 103 b is 100 ° C.-110 ° C.-115 ° C.-120 ° C.-130 ° C., and the temperature of the neck 109 is 130 ° C. The rotational speed of the screw 102 was 25 rpm, and the shape of the screw 102 was a full flight shape. The take-up speed of the cable 1 was 10 m / min.

(3) Evaluation method The produced cable was evaluated by the following methods.

(Hardness before crosslinking treatment)
In order to evaluate the degree of deformation of the uncrosslinked sheath, the hardness of the outer layer before the crosslinking treatment was measured. Specifically, the hardness of the outer layer before crosslinking treatment, that is, the hardness of the outer layer material is measured using a JIS A type hardness tester, and if the value is 80 or more, the deformation resistance is excellent, and before the crosslinking treatment It is determined that the film is unlikely to be deformed even if wound up, and the product is evaluated as "good", and if it is less than 80, the product is considered highly likely to be deformed.

(Tensile elongation)
A tensile test was performed to evaluate the tensile elongation of the sheath after crosslinking treatment. Specifically, the sheath is peeled off from the cable after the crosslinking treatment, and the peeled sheath is punched out with a No. 6 dumbbell to prepare a test sample, and the test sample has a tensile speed of 200 mm / min and a length between marks with a Shopper testing machine. The elongation at break when pulled by 20 mm was measured. In the present example, if the elongation is 350% or more, the pass "○", and if less than 300%, the rejection "×".

(Oil resistance)
In order to evaluate the oil resistance of the sheath, a test sample was prepared in the same manner as tensile elongation, and the test sample was immersed in IRM 902 test oil at 100 ° C. for 24 hours. About the test sample before and behind immersion, the tension test was done like tensile elongation, and the residual ratio after immersion of breaking tensile strength was computed as shown in a following formula. If this residual ratio is 65% or more, the product has good oil resistance as excellent "◎", if 60% or more and less than 65%, good "「 ", less than 60% is not possible" X.
(Remaining percentage of broken tensile strength after immersion) = (tensile strength of test sample after immersion / tensile strength of test sample before immersion) × 100

(Adhesiveness between layers)
The adhesion between the inner layer and the outer layer was evaluated by conducting a peeling test and observing the fracture state of the layers. Specifically, first, the sheath after cross-linking treatment is cut into a length of 3 cm, and a cut of about 3 mm in length is externally made between the layers. Subsequently, after the inner layer was fixed, the outer layer was pinched with pliers and peeled until it had a length of about 2 cm. When the inner layer and the outer layer can not be peeled (when the outer layer is broken in the middle of peeling), the excellent adhesion is excellent "密 着", although peeling is possible, it is confirmed that the outer layer adheres to the inner layer visually and by hand In the case where the adhesion was judged to be sufficient, "Good" (○), and when the inner layer and the outer layer were respectively peeled off at the interface, the adhesion was regarded as insufficient and "Not good".

(Necessity of cross-linking equipment)
In this example, when the heating condition for crosslinking is low at less than 100 ° C. or when the crosslinking equipment is not particularly required, the cost is acceptable as low cost “○”, the heating condition is high, or a special crosslinking equipment is used. If it becomes necessary, it is regarded as high cost and it is regarded as a rejection "x".

(4) Evaluation results The evaluation results are shown in Table 3 below. As shown in Table 3, in Example 1, the hardness before crosslinking treatment is as high as 84, and even if the cable is wound up in a drum shape before the crosslinking treatment, deformation such as crushing may occur on the cable surface (outer layer) It was confirmed that the sex was low. Moreover, it was confirmed that the tensile strength of the sheath after the crosslinking treatment is as high as 440% and the tensile strength residual ratio after the oil resistance test is as high as 72%, and the mechanical properties and the oil resistance are excellent. Moreover, according to the peeling test between layers, the outer layer was broken and it was difficult to peel, so that it was confirmed that the adhesion between the inner layer and the outer layer is excellent. Further, in Example 1, since the silane crosslinking can be carried out with water, there is no need to set the heating condition to a high temperature at the time of crosslinking, and no special equipment such as electron beam irradiation is required, so the cost is low. I found that.

Example 2
In Example 2, the same inner layer material and outer layer material as in Example 1 were used, but the inner layer material and the outer layer material were not simultaneously silane crosslinked, but the inner layer material and the outer layer material were each silane crosslinked immediately after extrusion coating. A cable was produced in the same manner as in Example 1 except that the silane was separately cross-linked.
In Example 2, although silane crosslinking between layers did not proceed sufficiently and adhesion as high as in Example 1 could not be obtained, it was confirmed that sufficient adhesion could be secured. The other evaluations such as oil resistance and mechanical properties were confirmed to be good as in Example 1.

<Examples 3 and 4>
In Examples 3 and 4, a cable was produced in the same manner as in Example 1 except that the inner layer material was changed.
Specifically, in Example 3, a silane graft material B containing silane-grafted chlorinated polyethylene in which vinylsilane was graft-copolymerized was used as the inner layer material. In Example 3, although high adhesiveness as high as Example 1 was not obtained, it was confirmed that sufficient adhesiveness can be ensured. The reason is presumed as follows. That is, according to methacrylic silane, compatibility with chlorinated polyethylene is higher than that of vinylsilane and graft copolymerization can be performed uniformly, so that it is possible to reduce a portion where the amount of silane compound is locally small and adhesion is weak. .
In Example 4, a silane graft material C containing a silane-grafted chloroprene rubber was used as the inner layer material. In Example 4, it was confirmed that the evaluation result is good as in Example 1.
In Example 4, the extrusion conditions for the silane-grafted chloroprene rubber as the inner layer material were as follows. The temperature of the cylinder 103a to the cylinder 103b is 80 ° C.-80 ° C.-85 ° C.-90 ° C.-100 ° C., the temperature of the neck 109 is 100 ° C., the temperature of the crosshead 110 is 100 ° C., and the temperature of the die 105 is 100 ° C. . The rotational speed of the screw 102 was 15 rpm, and the shape of the screw 102 was a full flight shape. The take-up speed of the cable 1 was 10 m / min.

Comparative Example 1
In Comparative Example 1, a cable was produced by changing the silane graft material A to a material for chemical crosslinking as the inner layer material. Specifically, first, a material for chemical crosslinking is extrusion-coated on the outer periphery of the EP rubber insulator core, sealed with pressurized steam, inserted into a heating tube heated to a high temperature of 180 ° C., and the inner layer material Chemical crosslinking was performed to form an inner layer. Thereafter, the same outer layer material as in Example 1 was extrusion-coated on the outer periphery of the inner layer and silane cross-linked to form an outer layer, whereby a cable was produced.
In Comparative Example 1, it is confirmed that high adhesion can not be obtained because crosslinking between layers does not proceed sufficiently, probably because the crosslinking method differs between the inner layer material and the outer layer material. In addition, since it is necessary to carry out heat treatment at a high temperature to chemically crosslink the inner layer, it has been confirmed that the cost is higher than in the example.

Comparative Example 2
In Comparative Example 2, a cable was produced in the same manner as in Example 1 except that the inner layer material containing the silane graft material A used in Example 1 was extrusion-coated to form a single-layer sheath.
In Comparative Example 2, the sheath was made of a material containing only silane-grafted chlorinated polyethylene without silane-grafted polyethylene, so the hardness before heat treatment was as low as 70, and the sheath surface was deformed when wound into a drum shape. It was confirmed that the possibility is high. In addition, in the comparative example 2, since the sheath of single layer structure was formed, it did not test about the adhesiveness of an interlayer.

In Comparative Example 3, a cable was produced in the same manner as in Example 1 except that the inner layer material containing the silane graft material C used in Example 4 was extrusion-coated to form a single-layer sheath.
In Comparative Example 3, as in Comparative Example 2, since the sheath is made of a material containing only silane-grafted chloroprene rubber without silane-grafted polyethylene, the hardness before heat treatment is as low as 53, and when wound into a drum shape It has been confirmed that the sheath surface is likely to be deformed. In addition, in the comparative example 3, since the sheath of single layer structure was formed, it did not test about the adhesiveness of an interlayer.

Comparative Example 4
Comparative Example 4 is the same as Example 1 except that the material for chemical crosslinking is extrusion-coated and heat-treated under the same conditions as Comparative Example 1 to chemically crosslink to form a single-layer sheath. Was produced.
In Comparative Example 4, although various properties such as oil resistance and mechanical properties were confirmed to be good, it was confirmed that the cost was high because it was necessary to perform heat treatment at a high temperature for chemical crosslinking. .

Comparative Example 5
In Comparative Example 5, an EP rubber insulator core is used as the outer layer material containing the silane graft material A containing silane-grafted chlorinated polyethylene and the silane graft material C containing silane-grafted polyethylene in the predetermined ratio, used in Example 1. A cable was produced in the same manner as in Example 1 except that extrusion coating was performed on the outer circumference of the above to form a single-layer sheath.
In Comparative Example 5, since the sheath was formed by blending silane-grafted polyethylene, there is a low possibility that deformation such as crushing occurs on the cable surface (outer layer) even if the cable is wound in a drum shape before the crosslinking treatment. confirmed. However, it has been confirmed that the oil resistance of the sheath decreases and high oil resistance can not be maintained because the proportion of the silane-grafted polyethylene which is inferior in oil resistance increases in the sheath.

<Preferred embodiment of the present invention>
The preferred embodiments of the present invention will be additionally described below.

[Supplementary Note 1]
According to one aspect of the invention:
With a conductor,
And an insulating layer disposed on the outer periphery of the conductor,
The insulating layer has a laminated structure including an inner layer and an outer layer,
The inner layer comprises an inner layer material containing a silane-grafted chlorine-based polymer (A) in which a silane compound is graft-copolymerized to the chlorine-based polymer (a),
The outer layer is a silane-grafted chlorinated polyethylene (B) in which a silane compound is graft-copolymerized on a chlorinated polyethylene (b), and a silane-grafted polyethylene (C) in which a silane compound is graft-copolymerized on polyethylene (c); Consists of outer layer material including
An insulated wire is provided, wherein the inner layer and the outer layer are configured to be integrally silane cross-linked.

[Supplementary Note 2]
In the insulated wire of appendix 1, preferably
The chlorinated polymer (a) is at least one of chlorinated polyethylene, chloroprene rubber and chlorosulfonated polyethylene.

[Supplementary Note 3]
Preferably, in the insulated wire of appendix 1 or 2,
The silane compound has a methacryl group.

[Supplementary Note 4]
According to another aspect of the invention,
A conductor, an insulating layer disposed on the outer periphery of the conductor, and a sheath disposed on the outer periphery of the insulating layer,
The sheath has a laminated structure including an inner layer and an outer layer,
The inner layer comprises an inner layer material containing a silane-grafted chlorine-based polymer (A) in which a silane compound is graft-copolymerized to the chlorine-based polymer (a),
The outer layer is a silane-grafted chlorinated polyethylene (B) in which a silane compound is graft-copolymerized on a chlorinated polyethylene (b), and a silane-grafted polyethylene (C) in which a silane compound is graft-copolymerized on polyethylene (c); Consists of outer layer material including
A cable is provided, wherein the inner layer and the outer layer are integrally silane cross-linked.

1 Cable 11 Conductor 12 Insulating Layer 13 Sheath 14 Inner Layer 15 Outer Layer

Claims (4)

With a conductor,
And an insulating layer disposed on the outer periphery of the conductor,
The insulating layer has a laminated structure including an inner layer and an outer layer,
The inner layer comprises an inner layer material containing a silane-grafted chlorine-based polymer (A) in which a silane compound is graft-copolymerized to the chlorine-based polymer (a),
The outer layer is a silane-grafted chlorinated polyethylene (B) in which a silane compound is graft-copolymerized on a chlorinated polyethylene (b), and a silane-grafted polyethylene (C) in which a silane compound is graft-copolymerized on polyethylene (c); Consists of outer layer material including
An insulated wire, wherein the inner layer and the outer layer are configured to be integrally silane cross-linked.   The insulated wire according to claim 1, wherein the chlorinated polymer (a) is at least one of chlorinated polyethylene, chloroprene rubber and chlorosulfonated polyethylene.   The insulated wire according to claim 1, wherein the silane compound has a methacryl group. A conductor, an insulating layer disposed on the outer periphery of the conductor, and a sheath disposed on the outer periphery of the insulating layer,
The sheath has a laminated structure including an inner layer and an outer layer,
The inner layer comprises an inner layer material containing a silane-grafted chlorine-based polymer (A) in which a silane compound is graft-copolymerized to the chlorine-based polymer (a),
The outer layer is a silane-grafted chlorinated polyethylene (B) in which a silane compound is graft-copolymerized on a chlorinated polyethylene (b), and a silane-grafted polyethylene (C) in which a silane compound is graft-copolymerized on polyethylene (c); Consists of outer layer material including
The cable, wherein the inner layer and the outer layer are configured to be integrally silane cross-linked.

Images