JP2017033785A - Insulation wire and cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress deformation of a coated layer and maintain oil resistance high when using chlorinated polyethylene for the coated layer.SOLUTION: There is provided an insulation wire having a conductor, an insulation layer arranged on a circumference of the conductor, where the insulation layer has a laminate structure containing an inner layer and an outer layer, the inner layer consists of an inner layer material containing a silane graft chlorine-based polymer (A) where a silane compound is graft copolymerized to a chlorine-based polymer (a), the outer layer consists of an outer layer material containing a silane graft chlorinated polyethylene (B) where the silane compound graft copolymerized to chlorinated polyethylene (b) and a silane graft polyethylene (C) where the silane compound is graft polymerized to polyethylene (c) and the inner layer and the outer layer are constructed with silane crosslinked integrally.SELECTED DRAWING: Figure 1

Description

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

  Insulated wires and cables are provided with a coating layer (insulating layer, sheath, etc.) on the surface. The coating material for forming the coating layer varies depending on the use of the insulated wire or cable, and a rubber material is used particularly when flexibility is required. As such a rubber material, there is a chlorinated polymer, and among them, chlorinated polyethylene is used because of its excellent mechanical properties and oil resistance.

  Generally, when a coating layer is formed using a rubber material, the coating material is subjected to a crosslinking treatment in order to develop rubber elasticity and heat resistance. 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-grafted chlorinated polyethylene is prepared by adding a silane compound to chlorinated polyethylene, which is a rubber material, and performing graft copolymerization. Subsequently, the silane-grafted chlorinated polyethylene is extruded to form a coating layer, and then the silane crosslinking is performed by exposing the coating layer to moisture.

Japanese Patent Publication No. 50-35540

  However, in an insulated wire or cable, when the coating layer is crosslinked with silane, the coating layer may be deformed. In general, the silane crosslinking of the coating layer is performed by extruding a rubber material and winding an uncrosslinked insulated wire or cable in a drum shape and then exposing it to moisture. For this reason, the uncrosslinked coating layer is crushed and deformed by its own weight or tension of the cable or the like before the rubber elasticity is exhibited by the crosslinking. As a result, the coating layer is silane-crosslinked in a deformed state, and the surface appearance is impaired.

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

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a technique for suppressing deformation of a coating layer and maintaining high oil resistance when chlorinated polyethylene is used for the coating layer. And

According to one aspect of the invention,
Conductors,
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 is made of an inner layer material containing a silane-grafted chlorine polymer (A) obtained by graft copolymerizing a silane compound with a chlorine polymer (a),
The outer layer includes a silane-grafted chlorinated polyethylene (B) obtained by graft copolymerizing a silane compound with chlorinated polyethylene (b), a silane-grafted polyethylene (C) obtained by graft copolymerizing a silane compound with polyethylene (c), and Made of outer layer material including
An insulated wire is provided in which 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 is made of an inner layer material containing a silane-grafted chlorine polymer (A) obtained by graft copolymerizing a silane compound with a chlorine polymer (a),
The outer layer includes a silane-grafted chlorinated polyethylene (B) obtained by graft copolymerizing a silane compound with chlorinated polyethylene (b), a silane-grafted polyethylene (C) obtained by graft copolymerizing a silane compound with polyethylene (c), and Made of outer layer material including
A cable is provided wherein the inner layer and the outer layer are configured to be 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.

It is the schematic of the cross section of the cable which concerns on one Embodiment of this 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 by the present inventors, it has been found that in a chlorinated polyethylene that is a rubber material, a plastic material may be mixed in order to suppress deformation before silane crosslinking. Plastic materials generally have more crystal components (high crystallinity) than rubber materials and have a high melting point, so that they are not easily deformed even when uncrosslinked. Therefore, by mixing the plastic material with the rubber material, the hardness can be increased and the deformation resistance can be improved.

  Furthermore, the present inventors have examined a plastic material and found that polyethylene is a good plastic material. Polyethylene can be graft-copolymerized with a silane compound in the same manner as chlorinated polyethylene, and can be crosslinked with silane. That is, silane-grafted polyethylene is mixed with silane-grafted chlorinated polyethylene and reacted with moisture, whereby these can be integrally crosslinked with silane. Therefore, according to polyethylene, even when mixed with chlorinated polyethylene, a degree of crosslinking equivalent to that when chlorinated polyethylene alone is silane-crosslinked can be obtained without reducing the degree of crosslinking of the mixture.

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

  Then, it examined by making the coating layer into a multilayer structure and coating the outer layer thinly with the mixed material containing silane graft chlorinated polyethylene and silane graft polyethylene. As a result, the outer layer having excellent deformation resistance can maintain high deformation resistance as a whole coating layer, and the ratio of polyethylene in the coating layer can be reduced to suppress a decrease in oil resistance. It has been found that high levels of deformation resistance and oil resistance can be obtained.

  In addition, the inner layer of the coating layer is preferably a material having high compatibility with the mixed material of the outer layer from the viewpoint of adhesion to the outer layer, and among them, it has been found that a chlorine-based polymer is good. Moreover, it has been found that by extruding each of the inner layer and the outer layer and simultaneously silane-crosslinking, a cross-linking reaction between these layers can be expressed, and silane cross-linking can be integrally performed, and adhesion can be greatly improved.

  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 cross-sectional view 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, oxygen-free copper, or the like, a copper alloy wire, a metal wire made of aluminum, silver, or the like, or a twisted wire obtained by twisting metal wires can be used. The outer diameter of the conductor 11 can be appropriately changed according to the use of the cable 1.

(Insulating layer 12)
An insulating layer 12 is provided so as 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 ethylene propylene rubber. The thickness of the insulating layer 12 can be appropriately changed according to the use of the cable 1.

(Sheath 13)
A sheath 13 is provided so as 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 chlorinated polymer (A), the outer layer 15 is made of an outer layer material containing silane-grafted chlorinated polyethylene (B) and silane-grafted polyethylene (C), and the sheath 13 is made of an inner layer. After the material and the outer layer material are laminated and extruded, the inner layer 14 and the outer layer 15 are integrally silane-crosslinked by being simultaneously silane-crosslinked. 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 silane crosslinking an inner layer material containing a silane-grafted chlorine polymer (A). Since the inner layer material contains the silane-grafted chlorine polymer (A), it 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 adhesiveness with the outer layer 15. In addition, in the present embodiment, the inner layer 14 and the outer layer 15 are configured to be integrally silane-crosslinked, so that the adhesion is further improved. Moreover, since the inner layer 14 contains the silane graft | grafting chlorine 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 contains a silane-grafted chlorine polymer (A).

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

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

The silane compound has an unsaturated bond group and a hydrolyzable silane group. A silane compound introduce | transduces a silane group into a chlorine-type polymer (a) by graft-copolymerizing to a chlorine-type polymer by the radical which arises by decomposition | disassembly of a peroxide.
The unsaturated bond group is not limited as long as it can graft-polymerize a silane compound to the chlorine-based polymer (a), and examples thereof include a vinyl group, a methacryl group, and an acrylic group. Among these, a methacryl group is preferable. A silane compound having a methacrylic group (methacrylic silane) has good compatibility with a chlorine-based polymer and can uniformly introduce a crosslinked structure into the chlorine-based polymer.
Examples of the hydrolyzable silane group include those having a hydrolyzable structure such as a halogen, an alkoxy group, an acyloxy group, and a phenoxy group. Examples of the silane group having a hydrolyzable structure include a halosilyl group, an alkoxysilyl group, an acyloxysilyl group, and a phenoxysilyl group.

  Specific examples of methacrylic silane include 3-methacryloxypropyltrimethoxysilane and 3-methacryloxypropyltriethoxysilane, which may be used alone or in combination.

  The amount of the silane compound to be graft copolymerized with the chlorine polymer (a) may be appropriately changed depending on the degree of crosslinking of the inner layer 14 or the reaction conditions (for example, temperature, time, etc.) at the time of crosslinking. Specifically, the compounding amount of the silane compound is preferably 0.1 parts by mass or more and 10 parts by mass or less, and 1.0 parts by mass or more and 5.0 parts by mass with respect to 100 parts by mass of the chlorine-based polymer (a). It is more preferable that the amount is not more than parts. 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 it exceeds the above range, premature crosslinking occurs before silane crosslinking, and foreign matter (tubes) due to crosslinking is formed in the inner layer 14, which may lead to a poor appearance.

  The peroxide is not particularly limited as long as the silane compound can be graft copolymerized with the chlorine-based polymer (a). Specific examples of the peroxide include dicumyl peroxide, 1,1-di (t-butylperoxy) cyclohexane, t-butylperoxyisopropyl carbonate, t-amylperoxyisopropyl carbonate, and 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 or the like can be used. These may be used alone or in combination of two or more.

  The inner layer material is obtained by adding a peroxide and a silane compound to the chlorine-based polymer (a) and heating and kneading to graft copolymerize the silane compound with the chlorine-based polymer (a) in the presence of the peroxide. . Thereby, a silane graft chlorine polymer (A) is formed, and an inner layer material is prepared.

(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 graft copolymerized with a silane compound and is excellent in compatibility with the inner layer resin composition. Therefore, the outer layer 15 is excellent in adhesiveness with the inner layer 14. In addition, in the present embodiment, the inner layer 14 and the outer layer 15 are configured to be integrally silane-crosslinked, so that the adhesion is further improved. In addition, the outer layer material includes silane-grafted polyethylene (C) having high crystallinity and high hardness, and is excellent in deformation resistance even when left uncrosslinked. Therefore, the outer layer 15 made from the material has little deformation such as crushing and has a good appearance. It is. Further, the outer layer 15 includes silane-grafted polyethylene (C) and tends to have low oil resistance. However, in this embodiment, the outer layer 15 is configured as a part of the laminated structure of the sheath 13 to reduce the proportion of the sheath 13. Therefore, the desired high oil resistance can be obtained without greatly reducing the oil resistance of the entire sheath 13.

  The outer layer material includes silane-grafted chlorinated polyethylene (B) and silane-grafted polyethylene (C).

The silane-grafted chlorinated polyethylene (B) is obtained by graft-copolymerizing a silane compound to the chlorinated polyethylene (b) using a peroxide, and mainly contributes to improving the oil resistance of the outer layer 15.
The 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 setting the grafting rate of the silane compound and the degree of crosslinking when crosslinked to a desired range, for example, 25% to 45%. Preferably, it is 30% or more and 40% or less.
As the silane compound to be graft-polymerized to the chlorinated polyethylene (b), those described above can be used, and a silane compound having a methacryl group (methacryl silane) is preferable.
As the peroxide, those described above can be used.

  The amount of the silane compound to be graft copolymerized with the chlorinated polyethylene (b) may be appropriately changed depending on the degree of crosslinking of the outer layer 15 or the reaction conditions (for example, temperature, time, etc.) when crosslinking. From the viewpoint of obtaining a high degree of crosslinking when the silane is crosslinked in the outer layer 15 and suppressing appearance defects due to early crosslinking, the blending amount of the silane compound is 0.1 parts by mass with respect to 100 parts by mass of chlorinated polyethylene. The amount is preferably 10 parts by mass or less, and more preferably 1.0 part by mass or more and 5.0 parts by mass or less.

Silane-grafted polyethylene (C) is obtained by graft-copolymerizing polyethylene (c) with a silane compound 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 examples thereof include high-density polyethylene (HDPE), low-density polyethylene (LDPE), and linear low-density polyethylene (LLDPE). Can be used. From the viewpoint of further improving the deformation resistance of the outer layer material in an uncrosslinked state, it is preferable to use a polyethylene (c) having a high density. This is because polyethylene (c) has higher crystal components and higher hardness as the density increases. 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, which may impair the flexibility of the sheath 13. Therefore, the upper limit value of the density is preferably 0.95 g / ml or less.
As the silane compound to be graft-polymerized to polyethylene (c), those described above can be used, and a silane compound having a methacryl group (methacryl silane) is preferable.
As the peroxide, those described above can be used.

  The amount of the silane compound to be graft copolymerized with the polyethylene (c) may be appropriately changed depending on the degree of crosslinking of the outer layer 15 or the reaction conditions (for example, temperature, time, etc.) at the time of crosslinking. From the viewpoint of obtaining a high degree of crosslinking when the silane is crosslinked in the outer layer 15 and suppressing appearance defects due to early crosslinking, the blending amount of the silane compound is 0.1 mass relative to 100 mass parts of polyethylene (c). It is preferably no less than 5 parts by mass and no greater than 1.0 part by mass, and more preferably no less than 1.0 part by mass and no greater 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) is increased, the deformation resistance of the outer layer material is increased, while the oil resistance of the outer layer 15 is decreased. Therefore, from the viewpoint of obtaining a high level of deformation resistance and oil resistance, The ratio of the silane-grafted chlorinated polyethylene (B) and the silane-grafted polyethylene (C) is preferably 55:45 to 90:10 in terms of 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 uncrosslinked outer layer material when the outer layer 15 is formed. On the other hand, when the thickness of the outer layer 15 is excessively large, the ratio of the outer layer 15 to the sheath 13 is increased, and the oil resistance of the entire sheath 13 may be decreased. Therefore, the thickness 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 preferable to prepare. Thereby, a silane compound can be graft-copolymerized under optimum conditions for the component (b) and the component (c), respectively. The graft reaction conditions (temperature, time, etc.) at this time are not particularly limited.

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

  As the silanol condensation catalyst, for example, a group II element such as magnesium or calcium, a group VIII element such as cobalt or iron, a metal element such as tin, zinc and titanium, or a metal compound 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, dioctyltin dineodecanoate, dibutyltin dilaurate, dibutyltin diacetate, dibutyltin dioctaate, stannous acetate, stannous cablate, lead naphthenate, zinc caprylate, naphthene Cobalt acid or the like can be used. As the amine compound, ethylamine, dibutylamine, hexylamine, pyridine and the like can be used. As the acid, inorganic acids such as sulfuric acid and hydrochloric acid, and organic acids such as toluenesulfonic acid, acetic acid, stearic acid, and maleic acid can be used.

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

  Further, in the kneading operation such as graft copolymerization of the silane compound, it is preferable to knead using a kneading reaction apparatus such as a roll machine, an extruder, a kneader, a mixer, or an autoclave.

  Moreover, the kind of the silane compound to be graft copolymerized with the chlorinated polymer (a), the chlorinated polyethylene (b) and the polyethylene (c) may be the same or different.

<Cable manufacturing method>
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, an extrusion step of extruding the inner layer material and the outer layer material on the outer periphery of the insulating layer 12, and A crosslinking step of exposing the inner layer material and the outer layer material to moisture and simultaneously crosslinking the silane.

  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 covered 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, for example, the atmosphere and brought into contact with moisture. As a result, the (A) component contained in the inner layer material, the (B) component and the (C) component contained in the outer layer material are converted into silanol groups by hydrolysis of the silane groups in the respective molecular chains. Silane crosslinking is achieved by dehydration condensation to form a crosslinked structure. Since the silane crosslinking occurs not only in each of the inner layer material and the outer layer material but also in these layers, the inner layer 14 and the outer layer 15 are integrally silane crosslinked in the sheath 13.

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

[Other Embodiments 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, In the range which does not deviate from the summary, it can change suitably.

  In the above-described embodiment, the case where the inner layer material and the outer layer material are extruded onto the outer periphery of the insulating layer 12 and then simultaneously silane-crosslinked is described. However, the present invention is not limited to this. For example, the inner layer material may be extruded and silane crosslinked to form the inner layer 14, and then the outer layer material may be extruded onto the outer periphery of the inner layer 14 and silane crosslinked to form the outer layer 15. In this case, when the outer layer material extruded onto the outer periphery of the inner layer 14 is subjected to silane crosslinking, silane crosslinking between the inner layer 14 and the outer layer material proceeds, and high adhesion is obtained between the inner layer 14 and the outer layer 15. It is done.

  In the above-described embodiment, the case where the cable 1 includes one insulated wire provided with the insulating layer 12 on the outer periphery of the conductor 11 has been described. However, the cable 1 is a twist obtained by twisting two or more insulated wires together. A line may be provided.

  In the above-described embodiment, the case where the sheath 13 has a laminated structure including the inner layer 14 and the outer layer 15 in the cable 1 has been described, but the present invention is not limited to this. For example, in an insulated wire in which an insulating layer is formed on the outer periphery of a 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 with reference to examples. The present invention is not limited to the following examples.

  In the examples and comparative examples, the following materials were used.

The following were used as polymer components.
Chlorinated polyethylene (Mooney viscosity (ML _{1 + 4} ): 55): “CM352L” manufactured by Hangzhou Science & Technology Co., Ltd.
Chloroprene rubber (non-vulcanized modified type, Mooney viscosity (ML _{1 + 4} ): 48): “Showprene W” manufactured by Showa Denko KK
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 silane compounds.
・ 3-Methacryloxypropyltrimethoxysilane: “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 the peroxide.
・ Dicumyl peroxide: “DCP” manufactured by NOF Corporation

The following were used as other additives.
・ Stabilizer (hydrotalcite): “Mugcellar 1” manufactured by Kyowa Chemical Industry Co., Ltd.
・ Stabilizer (epoxidized soybean oil): “New Sizer 510R” manufactured by NOF Corporation
・ Stabilizer (magnesium oxide): Kyowa Chemical Industry Co., Ltd. “Kyowa Mag 30”
・ Lubricant (polyethylene wax): “High Wax NL200” manufactured by Mitsui Chemicals, Inc.
・ Plasticizer (naphthenic 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): “Antimony trioxide” manufactured by Sumitomo Metal Mining Co., Ltd.
Antioxidant (4,4′-thiobis (3-methyl-6-tert-butylphenol)): “NOCRACK 300R” manufactured by Ouchi Shinsei Chemical Co., Ltd.
Antioxidant (2,2,4-trimethyl-1,2-dihydroquinoline polymer): “NOCRACK 224” manufactured by Ouchi Shinsei Chemical Co., Ltd.
Silanol condensation catalyst (dioctyltin dineodecanoate): “Neostan U-830” manufactured by Nitto Chemical 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 by blending shown in Table 1 below.

(Preparation of silane graft material A)
As silane graft material A, a composition containing silane grafted chlorinated polyethylene was prepared.
First, as shown in Table 1, 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, and 3 parts by mass of polyethylene wax. The mixture 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 kneading time was kneaded for 5 minutes after the addition of the stabilizer and the like was completed. Thereafter, the sheet obtained by kneading was pelletized into a 5 mm square shape to obtain pellets containing chlorinated polyethylene. In order to prevent adhesion between the pellets, 1 part by mass of talc was applied to the pellets.

Subsequently, grafting was performed on the obtained pellets.
Specifically, the obtained pellets were 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 pellets were mixed with silane mixture so that the peroxide was 0.5 parts by mass and methacrylsilane (KBM-503) was 5 parts by mass with respect to 100 parts by mass of chlorinated polyethylene. Was impregnated. Then, the pellet impregnated with the silane mixture was put into the cylinder 103a from the hopper 101 of the single screw extruder 100 shown in FIG. 2, and sent out from the cylinder 103a to the cylinder 103b by the rotation of the screw 102. At this time, the pellets were heated by the cylinders 103a and 103b and softened and kneaded to graft polymerize the silane compound to the chlorinated polyethylene. This formed the silane graft | grafting chlorinated polyethylene. Thereafter, the silane-grafted chlorinated polyethylene was fed to the head portion 104 of the extruder 100, and a strand 20 (length: 150 cm) of the silane-grafted chlorinated polyethylene was extruded from the die 105. Then, the strand 20 was introduced into the water tank 106, cooled with water, and drained with an air wiper 107. Thereafter, the strand 20 was pelletized with a pelletizer 108 to obtain pellets containing silane-grafted chlorinated polyethylene.
In the grafting process, a single screw extruder 100 having a screw diameter of 40 mm was used. The ratio L / D between the screw diameter D and the screw length L was 25. Further, the temperature of the cylinder 103a was 80 ° C., the temperature of the cylinder 103b was 200 ° C., the temperature of the head portion 104 was 200 ° C., and the temperature of the die 105 was 200 ° C. Moreover, the rotation speed of the screw 102 was 20 rpm (extrusion amount about 120 g / min), and the screw 102 was made into a full flight shape. Further, a die having a hole diameter of 5 mm and three holes was used as the die 105.

  Subsequently, a plasticizer, an antioxidant, carbon black, a flame retardant and a lubricant were added to the pellets containing silane-grafted chlorinated polyethylene in the formulation shown in Table 1, and kneaded using an 8-inch roll machine. At this time, the surface temperature of the roll was set to 100 ° C., and the kneading time was kneaded for 5 minutes after the addition of the stabilizer and the like was completed. Thereby, silane graft material A was prepared.

(Preparation of silane graft material B)
Silane graft material B changes the kind of silane compound from methacryl silane to vinyl silane (KBM-1003) and changes the amount of peroxide as appropriate to form silane-grafted chlorinated polyethylene in which vinyl silane is graft copolymerized. The silane graft material A was prepared in the same manner as described above.

(Preparation of composition C)
As the silane graft material C, a composition containing a silane-grafted chloroprene rubber was prepared.
Specifically, materials other than the 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 set to 80 ° C., and the kneading time was kneaded for 5 minutes after the addition of the stabilizer and the like was completed. Thereafter, the sheet obtained by kneading was pelletized into a 5 mm square shape to obtain pellets containing chloroprene rubber. In order to prevent adhesion between the pellets, 1 part by mass of talc was applied to the pellets.
This pellet was impregnated with a silane compound and grafted under the same conditions as in the silane graft material A to form a silane-grafted chloroprene rubber and prepare a silane graft material C.

(Preparation of silane graft material D)
As the silane graft material D, a composition containing silane grafted polyethylene was prepared.
Specifically, polyethylene pellets were sufficiently impregnated with silane mixture. At this time, as shown in Table 1 below, silane is added to the pellet so that the peroxide is 0.1 part 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 put into a single screw extruder 100 shown in FIG. 2, and a silane-grafted polyethylene is formed by grafting, and the strands are pelletized to contain the silane-grafted polyethylene. Composition D was prepared.
In the grafting process, a single screw extruder 100 having a screw diameter of 40 mm was used. The ratio L / D between the screw diameter D and the screw length L was 25. Further, the temperature of the cylinder 103a was 80 ° C., the temperature of the cylinder 103b was 200 ° C., and the temperature of the head portion 104 was 200 ° C. Moreover, the rotation speed of the screw 102 was 20 rpm (extrusion amount about 120 g / min), and the screw 102 was made into a full flight shape. Further, a die having a hole diameter of 5 mm and three holes was used as the die 105.

(Preparation of catalyst masterbatch)
Subsequently, separately from the compositions A to D, a catalyst master batch containing a silanol condensation catalyst was prepared.
Specifically, hydrotalcite is 6 parts by mass, epoxidized soybean oil is 6 parts by mass, polyethylene wax is 3 parts by mass, and silanol condensation catalyst with respect to 100 parts by mass of powdered chlorinated polyethylene. 2 parts by mass of dioctyltin dineodecanoate as a mixture 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 kneading was carried out for 3 minutes after the silanol condensation catalyst was added. Then, the sheet | seat which consists of kneaded materials was pelletized in the shape of 5 square mm, and the catalyst masterbatch was prepared.

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

<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 masterbatch to silane graft material A containing silane-grafted chlorinated polyethylene and dry blending. . In addition, the addition amount of the catalyst masterbatch was set to 1/20 mass for the chlorinated polyethylene of the silane graft material A.
Also, the silane graft material A containing silane-grafted chlorinated polyethylene and the silane graft material C containing silane-grafted polyethylene have a mass ratio of 105.48 so 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. 8 mm ² , rubber insulator thickness 1 mm, outer diameter 3.7 mm), and the outer layer material is extruded and coated so that the thickness is 1.5 mm, and then the outer layer material is 0.5 mm in thickness. Extrusion coated. Then, the cable 1 provided with the sheath 13 having the inner layer 14 and the outer layer 15 is produced by storing in a constant temperature and humidity chamber at a temperature of 60 ° C. and a relative humidity of 95% for 24 hours and crosslinking the inner layer material and the outer layer material with silane. did.
In the production of the cable 1, a single screw extruder with a screw diameter of 75 mm and a ratio L / D20 is used for extrusion of the inner layer material, and a single screw extruder with a screw diameter of 40 mm and a ratio of L / D20 is used for extrusion of the outer layer material. Each was used.
The extrusion conditions of the silane-grafted chlorinated polyethylene as the inner layer material were 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 for the outer layer material were as follows. The temperature of the cylinder 103a to the cylinder 103b was set to 100 ° C-110 ° C-115 ° C-120 ° C-130 ° C, and the temperature of the neck 109 was set to 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 method.

(Hardness before crosslinking)
In order to evaluate the deformation degree of the uncrosslinked sheath, the hardness of the outer layer before the crosslinking treatment was measured. Specifically, the hardness of the outer layer before the crosslinking treatment, that is, the hardness of the outer layer material is measured using a JIS A type hardness meter, and if the value is 80 or more, the deformation resistance is excellent. Even if it was wound up, it was judged that the possibility of deformation was low, and it was judged as acceptable “◯”.

(Tensile elongation)
A tensile test was performed to evaluate the tensile elongation of the sheath after the 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. The test sample is pulled with a shopper tester at a pulling speed of 200 mm / min and the length between the marked lines. The elongation at break when measured at a length of 20 mm was measured. In this example, if the elongation was 350% or more, it was judged as acceptable “◯”, and if it was less than 300%, it was judged as unacceptable “x”.

(Oil resistance)
In order to evaluate the oil resistance of the sheath, a test sample was prepared in the same manner as the tensile elongation, and the test sample was immersed in IRM902 test oil at 100 ° C. for 24 hours. About the test sample before and behind immersion, the tensile test was done similarly to tensile elongation, and the residual ratio after immersion of the breaking tensile strength was calculated as shown in the following formula. If the residual ratio is 65% or more, it is excellent as “◎” as having sufficient oil resistance, good “◯” if it is 60% or more and less than 65%, and impossible if it is less than 60%. × ”.
(Remaining ratio after breaking tensile strength after immersion) = (Tensile strength of test sample after immersion / Tensile strength of test sample before immersion) × 100

(Interlayer adhesion)
The adhesion between the inner layer and the outer layer was evaluated by performing a peel test and observing the fracture state between the layers. Specifically, first, the cross-linked sheath is cut to a length of 3 cm, and a cut of about 3 mm in length is made between the layers. Subsequently, after fixing the inner layer, the outer layer was pinched with pliers and peeled to a length of about 2 cm. If the inner layer and outer layer could not be peeled off (when the outer layer broke in the middle of peeling), it was confirmed that the outer layer adhered to the inner layer visually and by hand, although it could be peeled off as being excellent in adhesion. In this case, it was judged that the adhesiveness was sufficient, “Good”, and when the inner layer and the outer layer were peeled off at the interface, the adhesiveness was insufficient and judged as “No”.

(Necessity of cross-linking equipment)
In this example, when the heating conditions for crosslinking are as low as less than 100 ° C. or when the crosslinking equipment is not particularly required, it is acceptable as a low cost, “O”, on the contrary, the heating conditions are high, or special crosslinking equipment If it is necessary, it was judged as “No” because it was expensive.

(4) Evaluation results The evaluation results are shown in Table 3 below. As shown in Table 3, in Example 1, the hardness before the crosslinking treatment is as high as 84, and even if the cable is wound 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 property is low. Further, the tensile strength of the sheath after the crosslinking treatment was 440%, and the residual tensile strength ratio after the oil resistance test was 72%, both of which were high, and it was confirmed that the mechanical properties and the oil resistance were excellent. Moreover, according to the peeling test between layers, since the outer layer was broken and it was difficult to peel off, it was confirmed that the adhesion between the inner layer and the outer layer was excellent. Moreover, in Example 1, since silane crosslinking was possible with moisture, it was not necessary to increase the heating conditions at the time of crosslinking, and no special equipment such as electron beam irradiation was required, so the cost was low. I understood that.

<Example 2>
In Example 2, the same inner layer material and outer layer material as in Example 1 were used. However, the inner layer material and the outer layer material were not subjected to silane crosslinking at the same time. A cable was produced in the same manner as in Example 1 except that the silanes were separately crosslinked.
In Example 2, the silane crosslinking between the layers did not proceed sufficiently, and it was confirmed that sufficient adhesion could be ensured although the adhesion as high as Example 1 could not be obtained. About evaluation of oil resistance, mechanical characteristics, etc. other than that, it was 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, silane graft material B containing silane graft chlorinated polyethylene obtained by graft copolymerization of vinyl silane was used as the inner layer material. In Example 3, although the adhesiveness as high as Example 1 was not obtained, it was confirmed that sufficient adhesiveness can be ensured. The reason is estimated as follows. In other words, methacrylic silane has higher compatibility with chlorinated polyethylene than vinyl silane and can be uniformly graft-copolymerized. Therefore, it is possible to reduce a portion where there is little silane compound and adhesion becomes weak locally. .
In Example 4, silane graft material C containing silane graft chloroprene rubber was used as the inner layer material. In Example 4, it was confirmed that the evaluation results were good as in Example 1.
In Example 4, the extrusion conditions for the silane-grafted chloroprene rubber, which is 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 manufactured by changing the silane graft material A from the silane graft material A to the material for chemical crosslinking as the inner layer material. Specifically, first, a material for chemical cross-linking is extrusion coated on the outer periphery of the EP rubber insulator core, sealed with pressurized steam, and inserted into a heating tube heated to a high temperature of 180 ° C. The inner layer was formed by chemical crosslinking. Thereafter, the same outer layer material as in Example 1 was extrusion-coated on the outer periphery of the inner layer and silane-crosslinked to form an outer layer, thereby producing a cable.
In Comparative Example 1, it was confirmed that the cross-linking between the layers did not sufficiently proceed and high adhesion could not be obtained because the cross-linking method was different between the inner layer material and the outer layer material. Moreover, since it was necessary to perform a high-temperature heat treatment in order to chemically crosslink the inner layer, it was confirmed that the cost was higher than in the examples.

<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, since the sheath was made of a material containing only silane-grafted chlorinated polyethylene and not containing silane-grafted polyethylene, the hardness before heat treatment was as low as 70, and the sheath surface was deformed when wound in a drum shape. It was confirmed that the possibility is high. In Comparative Example 2, since a single-layer sheath was formed, no test was conducted on the adhesion between layers.

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 was made of a material that did not contain silane-grafted polyethylene and contained only silane-grafted chloroprene rubber, the hardness before heat treatment was as low as 53, and when wound in a drum shape It was confirmed that the sheath surface is highly likely to be deformed. In Comparative Example 3, since a single-layered sheath was formed, no test was conducted on the adhesion between layers.

<Comparative example 4>
In Comparative Example 4, the cable was the same as in Example 1 except that a material for chemical crosslinking was extrusion coated and heat treated under the same conditions as in Comparative Example 1 to form a single layer sheath. Was made.
In Comparative Example 4, it was confirmed that various properties such as oil resistance and mechanical properties were good, but because it was necessary to perform heat treatment at a high temperature in order to perform chemical crosslinking, it was confirmed that the cost was high. .

<Comparative Example 5>
In Comparative Example 5, 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 used in Example 1 in a predetermined ratio was used as an EP rubber insulator core. A cable was produced in the same manner as in Example 1 except that a single-layer sheath was formed by extrusion coating on the outer periphery of the cable.
In Comparative Example 5, since the sheath was formed by blending silane-grafted polyethylene, even if the cable was wound in a drum shape before the crosslinking treatment, the possibility that deformation such as crushing occurs on the cable surface (outer layer) is low. confirmed. However, since the ratio of silane-grafted polyethylene inferior in oil resistance in the sheath increased, it was confirmed that the oil resistance of the sheath was lowered and high oil resistance could not be maintained.

<Preferred embodiment of the present invention>
Hereinafter, preferred embodiments of the present invention will be additionally described.

[Appendix 1]
According to one aspect of the invention,
Conductors,
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 is made of an inner layer material containing a silane-grafted chlorine polymer (A) obtained by graft copolymerizing a silane compound with a chlorine polymer (a),
The outer layer includes a silane-grafted chlorinated polyethylene (B) obtained by graft copolymerizing a silane compound with chlorinated polyethylene (b), a silane-grafted polyethylene (C) obtained by graft copolymerizing a silane compound with polyethylene (c), and Made of outer layer material including
An insulated wire is provided in which the inner layer and the outer layer are configured to be integrally silane cross-linked.

[Appendix 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.

[Appendix 3]
In the insulated wire of appendix 1 or 2,
The silane compound has a methacryl group.

[Appendix 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 is made of an inner layer material containing a silane-grafted chlorine polymer (A) obtained by graft copolymerizing a silane compound with a chlorine polymer (a),
The outer layer includes a silane-grafted chlorinated polyethylene (B) obtained by graft copolymerizing a silane compound with chlorinated polyethylene (b), a silane-grafted polyethylene (C) obtained by graft copolymerizing a silane compound with polyethylene (c), and Made of outer layer material including
A cable is provided wherein the inner layer and the outer layer are configured to be integrally silane cross-linked.

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

Claims (4)

Conductors,
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 is made of an inner layer material containing a silane-grafted chlorine polymer (A) obtained by graft copolymerizing a silane compound with a chlorine polymer (a),
The outer layer includes a silane-grafted chlorinated polyethylene (B) obtained by graft copolymerizing a silane compound with chlorinated polyethylene (b), a silane-grafted polyethylene (C) obtained by graft copolymerizing a silane compound with polyethylene (c), and Made of outer layer material including
The insulated wire is configured such that the inner layer and the outer layer are integrally silane-crosslinked.   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 or 2, 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 is made of an inner layer material containing a silane-grafted chlorine polymer (A) obtained by graft copolymerizing a silane compound with a chlorine polymer (a),
The outer layer includes a silane-grafted chlorinated polyethylene (B) obtained by graft copolymerizing a silane compound with chlorinated polyethylene (b), a silane-grafted polyethylene (C) obtained by graft copolymerizing a silane compound with polyethylene (c), and Made of outer layer material including
The cable, wherein the inner layer and the outer layer are configured to be integrally silane cross-linked.

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