JP6504484B2 - Electric wire cable and method of manufacturing silane cross-linked product, method of manufacturing electric wire, method of manufacturing cable - Google Patents

Description

  The present invention relates to a method of producing a wire cable and a silane cross-linked product, a method of producing a wire, and a method of producing a cable.

  Chlorinated polyethylene is a thermoplastic elastomer excellent in various properties such as heat resistance and abrasion resistance, and in wire cables such as electric wires and cables, a forming material of a covering layer (for example, an insulating layer or sheath) covering the outer periphery of a conductor It is used as

  Generally, when forming a coating layer using chlorinated polyethylene, in order to improve oil resistance etc. of a coating layer, a crosslinking treatment is applied. 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, in the case of forming a coating layer by subjecting chlorinated polyethylene to silane crosslinking, first, a silane compound is mixed with chlorinated polyethylene and kneaded. Subsequently, a chlorinated polyethylene is graft copolymerized with a silane compound by heating to form a silane crosslinkable composition containing silane-grafted chlorinated polyethylene. Next, the silane crosslinkable composition is extruded to cover the outer periphery of the conductor and molded into a predetermined shape. Thereafter, the molded body is brought into contact with moisture to advance the crosslinking reaction to form a silane-crosslinked coating layer.

Japanese Patent Publication No. 50-35540

  By the way, various additives are mix | blended with the silane crosslinkable composition which forms a coating layer according to the characteristic calculated | required by the coating layer. For example, various additives such as a plasticizer which imparts flexibility to the coating layer, a stabilizer which imparts resistance to the external environment, and carbon black which imparts abrasion resistance and the like are blended. These additives are generally blended simultaneously with the blending of the silane compound to the chlorinated polyethylene from the viewpoint of simplifying the production process. Then, by kneading and heating these, the chlorinated polyethylene is graft copolymerized with the silane compound in the presence of the additive.

However, when a silane compound is graft-copolymerized to chlorinated polyethylene in the presence of a plasticizer among additives, the plasticizer may inhibit the graft copolymerization. As a result, in silane-grafted chlorinated polyethylene, the graft copolymerization ratio of the silane compound (hereinafter also referred to as grafting ratio) is low, and finally, a sufficient degree of crosslinking can not be obtained when silane crosslinking is performed. There is.
On the other hand, it is conceivable to blend a plasticizer that adversely affects graft copolymerization after graft copolymerization, but since the graft copolymerization is carried out at a relatively high temperature, it is plasticized to a silane crosslinkable composition heated to a high temperature. When the agent is blended, the plasticizer may volatilize. In addition, since it takes time to disperse the plasticizer in the silane crosslinkable composition, premature crosslinking occurs and it becomes difficult to extrude the silane crosslinkable composition to form a coating layer.
In addition, when a plasticizer is not mix | blended, in the coating layer formed, although sufficient crosslinking degree is obtained, elongation is low and it can not satisfy | fill the flexibility requested | required of a coating layer.

  The present invention has been made in view of the above problems, and a wire cable having a coating layer having a high degree of crosslinking and excellent flexibility, a method of producing a silane crosslinked product, a method of producing a wire, and a method of producing a cable Intended to provide.

According to one aspect of the present invention,
Adding a non-mineral oil plasticizer to a chlorinated polyethylene consisting of a base polymer and then adding a silane compound and a peroxide to obtain a mixture;
Grafting the silane compound onto the chlorinated polyethylene in the presence of the peroxide by heating and kneading the mixture to obtain a silane crosslinkable composition;
Contacting the silane crosslinkable composition with water to obtain a cross-linked silane , wherein the non-mineral oil plasticizer is at least one of chlorinated paraffin and phthalate ester plasticizers. There is provided a process for the preparation of silane crosslinks, which is one .
According to another aspect of the invention,
Adding a non-mineral oil plasticizer to a chlorinated polyethylene consisting of a base polymer and then adding a silane compound and a peroxide to obtain a mixture;
Grafting the silane compound onto the chlorinated polyethylene in the presence of the peroxide by heating and kneading the mixture to obtain a silane crosslinkable composition;
Extruding the silane crosslinkable composition onto a conductor coated insulating layer to form a sheath;
There is provided a method of manufacturing a cable comprising the steps of contacting the sheath with water and silane crosslinking.
According to another aspect of the invention,
Adding a non-mineral oil plasticizer to a chlorinated polyethylene consisting of a base polymer and then adding a silane compound and a peroxide to obtain a mixture;
Grafting the silane compound onto the chlorinated polyethylene in the presence of the peroxide by heating and kneading the mixture to obtain a silane crosslinkable composition;
Extruding the silane crosslinkable composition onto a conductor to form an insulating layer;
There is provided a method of producing an electric wire, comprising the steps of contacting the insulating layer with water to crosslink the silane.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the electric wire cable provided with the coating layer which is highly crosslinked and which is excellent in flexibility, a silane crosslinked material, an electric wire, and a cable is obtained.

It is a sectional view showing a schematic structure of a cable concerning one embodiment of the present invention. It is the schematic which shows the grafting process using the single screw extruder in an Example. It is the schematic which shows preparation of the cable in an Example.

  As described above, when a plasticizer is blended as an additive, since the graft copolymerization of the silane compound is inhibited, a sufficient degree of crosslinking may not be obtained when silane crosslinking is performed. The plasticizer is an additive generally used to increase the flexibility of the coating layer, and, for example, a mineral oil refined from crude oil is used. Mineral oils include paraffinic oils, naphthenic oils and aromatic oils, depending on the content ratio of paraffin, naphthene and aromatic component, respectively. However, according to the study of the present inventors, it has been found that, since these mineral oils greatly inhibit the graft copolymerization of silane compounds among plasticizers, a sufficient degree of crosslinking can not be obtained when silane crosslinking is carried out.

  From this, when the present inventors examined using not a mineral oil type but a non mineral oil type as a plasticizer, for example, non mineral oil type such as chlorinated paraffin and phthalate ester plasticizers According to the plasticizer, the grafting ratio to chlorinated polyethylene can be increased without inhibiting the graft copolymerization of the silane compound. Thereby, a high degree of crosslinking can be obtained when silane crosslinking is performed. Moreover, since the non-mineral oil based plasticizer is also excellent in compatibility with the silane graft chlorinated polyethylene, it is difficult to elute from the coating layer, and bleeding can be suppressed. Therefore, according to the non-mineral oil plasticizer, a coating layer having a high degree of crosslinking and excellent flexibility can be formed.

  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.

(1) Silane Crosslinkable Composition First, a silane crosslinkable composition for forming a coating layer of a wire cable will be described.

  The silane crosslinkable composition contains silane-grafted chlorinated polyethylene and a nonmineral oil plasticizer.

  Silane-grafted chlorinated polyethylene is obtained by mixing chlorinated polyethylene, a silane compound and a peroxide, and graft copolymerizing the silane compound to chlorinated polyethylene in the presence of peroxide. Silane-grafted chlorinated polyethylene has a silane group derived from a graft-copolymerized silane compound in the molecular structure, and when contacted with water, the silane group in the molecular structure is hydrolyzed to form a silanol group. The silane groups are configured to be cross-linked by dehydration condensation of these silanol groups to form a cross-linked structure.

  Chlorinated polyethylene has a structure in which a part of hydrogen in a hydrocarbon skeleton such as polyethylene is substituted by a chlorine atom having a high electronegativity, and is a component having a large polarity. Chlorinated polyethylene can be 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 chlorinated polyethylene is preferably 25% or more and 45% or less from the viewpoint of obtaining well-balanced properties such as heat resistance, oil resistance and flame retardancy of the coating layer, and when forming the coating layer It is more preferable that it is 30% or more and 40% or less from a viewpoint of improving processability.

  The silane compound has an unsaturated bondable group and a hydrolyzable silane group. A silane compound introduce | transduces a silane group into chlorinated polyethylene by graft-copolymerizing to chlorinated polyethylene by unsaturated bondable group.

  The unsaturated bondable group of the silane compound is not limited as long as it can graft copolymerize the silane compound to chlorinated polyethylene, and examples thereof include a vinyl group, a methacryl group and an acryl group. Among these, a methacryl group is preferable as the unsaturated bonding group. A methacrylsilane compound having a methacryl group is excellent in compatibility with chlorinated polyethylene as compared with a vinylsilane compound having a vinyl group, and is easily dispersed in chlorinated polyethylene. Therefore, graft polymerization is uniformly carried out on chlorinated polyethylene to obtain uniformity. Can form a cross-linked structure. Furthermore, they are less flammable than vinylsilane compounds, and are excellent in handleability.

  As a hydrolyzable silane group of a silane compound, 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.

  Specific examples of the silane compound include 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, and methacrylsilane such as 3-methacryloxypropylmethyldiethoxysilane. Can be used.

  The amount by which the silane compound is graft-copolymerized to chlorinated polyethylene, that is, the compounding amount of the silane compound to be incorporated into the chlorinated polyethylene is the degree of crosslinking of the final molded article (coating layer), or the reaction conditions for crosslinking It may be suitably changed depending on (for example, temperature, time, etc.). 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 or less with respect to 100 parts by mass of the chlorinated polyethylene. It is more preferable that With such a blending amount, an appropriate degree of crosslinking can be obtained when silane crosslinking is carried out.

  The peroxide is for graft copolymerization of a silane compound to chlorinated polyethylene. Specifically, peroxides generate oxyradicals by thermal decomposition. The oxy radical generates a chlorinated polyethylene radical by extracting hydrogen in the chlorinated polyethylene. Then, the radical of the chlorinated polyethylene reacts with the unsaturated bond group (for example, vinyl group, methacrylic group, etc.) of the silane compound to graft copolymerize the silane compound to the chlorinated polyethylene. Thus, the peroxide generates an oxy radical, resulting in the graft copolymerization of the silane compound onto the chlorinated polyethylene.

  As the peroxide, for example, an organic peroxide can be used. Organic peroxides have high hydrogen extraction ability to extract hydrogen from chlorinated polyethylene, and can be pyrolyzed at a temperature at which chlorinated polyethylene is not easily deteriorated (it is difficult to be dehydrochlorinated) to generate an oxy radical. Since the degradation start temperature of chlorinated polyethylene is about 200 ° C., it is preferable to use an organic peroxide having a half-life temperature of 120 ° C. or more and 200 ° C. or less as the peroxide. From the viewpoint of shortening the time required for the grafting reaction, it is better to use an organic peroxide having a one-minute half-life temperature of 150 ° C. or more and 200 ° C. or less. The one-minute half-life temperature is a temperature at which the half-life of the peroxide is one minute.

  Specifically, as peroxides, 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. Among these, dicumyl peroxide having a one-minute half-life temperature of about 175 ° C. may be used.

  The compounding amount of the peroxide may be appropriately changed according to the compounding amount of the silane compound, and is preferably 0.03 parts by mass or more and 3.0 parts by mass or less with respect to 100 parts by mass of the chlorinated polyethylene. With such a blending amount, an appropriate degree of crosslinking can be obtained when silane crosslinking is carried out.

  In the silane crosslinkable composition, a plasticizer is blended to increase the flexibility of the coating layer, but in the present embodiment, as described above, the viewpoint of causing the silane compound to react so as to increase the grafting rate. From non-mineral oil plasticizers are used. The plasticizer does not significantly inhibit the graft copolymerization of the silane compound to the chlorinated polyethylene, and therefore the grafting ratio of the silane compound can be increased. And since it is excellent also in compatibility with silane grafting chlorinated polyethylene, it is hard to bleed from a silane crosslinkable composition.

The non-mineral oil plasticizer is not particularly limited as long as it has a large electronegativity atom and a large polar functional group, but at least one of chlorinated paraffin and phthalate ester plasticizers may be used. preferable.
Chlorinated paraffin has a chemical structure similar to that of chlorinated polyethylene, and is incorporated into the cross-linked body when silane cross-linking chlorinated polyethylene is cross-linked, thereby improving the degree of cross-linking and oil resistance of the cross-linked body Etc. can be improved.
The phthalic acid ester plasticizer has an ester group, and has higher polarity than a mineral oil plasticizer, so that the oil resistance of the crosslinked product can be improved.
From the viewpoint of further improving the degree of crosslinking of the coating layer, chlorinated polyolefins that are incorporated into the crosslinked body are more preferable.

  It is preferable that the compounding quantity of a non-mineral oil type plasticizer is 1 to 30 mass parts with respect to 100 mass parts of chlorinated polyethylene. With such a compounding amount, bleeding from the coating layer can be suppressed while maintaining high flexibility of the coating layer.

  In addition, additives other than a plasticizer may be mix | blended with the silane crosslinkable composition. As another additive, for example, a silanol condensation catalyst that promotes silane crosslinking can be used. 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, dioctyltin dineodecanoate, dibutyltin dilaurate, dibutyltin diacetate, dibutyltin dioctaate, stannous acetate, stannous carboxylate, lead naphthenate, zinc caprylate, cobalt naphthenate, etc. Metal salts, amine compounds such as ethylamine, dibutylamine, hexylamine and pyridine, 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.

  Further, as other additives, fillers such as antioxidants (including anti-aging agents), fillers such as carbon black, flame retardants, lubricants, anti-copper discoloration inhibitors, crosslinking assistants, stabilizers and the like may be used.

(2) Method of Producing Silane Crosslinkable Composition Next, a method of producing the above-described silane crosslinkable composition will be described.

  First, a non-mineral oil plasticizer is added to chlorinated polyethylene and kneaded. Since non-mineral oil plasticizers have compatibility with chlorinated polyethylene, the plasticizer can be dispersed in chlorinated polyethylene. It is preferable to mix | blend non-mineral oil type plasticizer in 1 to 30 mass parts with respect to 100 mass parts of chlorinated polyethylene. In addition, when adding a plasticizer, you may add other additives, such as antioxidant and carbon black, for example.

  Subsequently, a silane compound and a peroxide are added to a mixture in which a plasticizer is dispersed in chlorinated polyethylene, and the mixture is kneaded. Since a non-mineral oil based plasticizer having compatibility with the silane compound is dispersed in the mixture, the silane compound can be uniformly dispersed in the mixture without aggregation. The silane compound is 0.1 to 10 parts by mass with respect to 100 parts by mass of chlorinated polyethylene, and the peroxide is 0.03 to 3.0 parts by mass with respect to 100 parts by mass of chlorinated polyethylene It is preferable to mix in

  Subsequently, the mixture to which the silane compound and the peroxide are added is heated and kneaded to graft copolymerize the silane compound to the chlorinated polyethylene in the presence of the peroxide. Thereby, a silane-grafted chlorinated polyethylene is formed, and a silane crosslinkable composition containing this and a non-mineral oil plasticizer and the like is obtained. In the present embodiment, since the silane compound is dispersed uniformly in the chlorinated polyethylene and uniformly dispersed and then graft copolymerized, the silane graft chlorinated polyethylene has a high graft ratio of the silane compound, and Silane groups are uniformly introduced. In addition, since non-mineral oil plasticizers have compatibility with silane-grafted chlorinated polyethylene, bleeding is suppressed.

  When the mixture is kneaded, 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. In addition, kneading conditions and grafting conditions (temperature, time, etc.) are not particularly limited.

(3) Silane Cross-Linked Product The silane cross-linked product is obtained by bringing the above-described silane cross-linkable composition into contact with water and subjecting the silane-grafted chlorinated polyethylene to silane cross-linking. In the present embodiment, since the silane graft chlorinated polyethylene has a high degree of grafting and the silane groups are uniformly introduced into the chemical structure, the silane crosslinked product obtained therefrom has a high degree of crosslinking and a crosslinked structure It will be formed homogeneously.

The silane cross-linked product preferably has a high degree of cross-linking, and a gel fraction which is an index of the cross-linking degree is 70% or more. If the gel fraction is less than 70%, the degree of crosslinking of the silane crosslinked product is low, so that, for example, when formed as a coating layer of a wire cable, sufficient mechanical properties can not be obtained. The upper limit value of the gel fraction is not particularly limited, and as the gel fraction is higher, more crosslinked structures are formed in the silane crosslinked product, and the mechanical properties thereof become higher.
The gel fraction is determined as follows. First, a sample formed of a silane crosslink is immersed in xylene, and xylene is heated to boil. Thereafter, a sample remaining without being dissolved in xylene (a sample after extraction with hot xylene) is taken out and dried, and the mass of the sample after extraction with hot xylene is measured. Then, the gel fraction of the silane crosslinked product is determined by calculating the ratio of the mass of the sample after extraction with hot xylene to the mass of the sample before extraction with hot xylene. Assuming that the mass of the sample before extraction with hot xylene is a and the mass of the sample after extraction with hot xylene is b, the gel fraction R is represented by the following equation.

R (%) = (b / a) x 100
The silane crosslinker also contains a nonmineral oil plasticizer. Therefore, the silane crosslinked product is easy to be stretched and is excellent in flexibility. Moreover, since the compatibility of the plasticizer is high, bleeding of the plasticizer is suppressed.

(4) Wire Cable Next, a wire cable according to an embodiment of the present invention will be described with reference to the drawings. In the present embodiment, the case of a cable including a sheath as a covering layer will be described as an example. FIG. 1 is a cross-sectional view showing a schematic structure of a cable according to an embodiment of the present invention.

  As shown in FIG. 1, the cable 1 of the present embodiment includes a conductor 10. As the conductor 10, 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 stranded wire obtained by twisting metal wires can be used. The outer diameter of the conductor 10 can be appropriately changed according to the application of the cable 1.

  An insulating layer 11 is provided to cover the outer periphery of the conductor 10. The insulating layer 11 is formed of a conventionally known resin composition, for example, a resin composition containing an ethylene-propylene rubber. The thickness of the insulating layer 11 can be appropriately changed according to the application of the cable 1.

  An outer covering layer 12 (sheath 12) is provided to cover the outer periphery of the insulating layer 11. The sheath 12 is formed of a silane crosslinked product in which the silane crosslinking composition is crosslinked. The sheath 12 has a high degree of crosslinking, and is configured to have a gel fraction of 70% or more.

The cable 1 is manufactured, for example, as follows.
First, for example, a copper wire is prepared as the conductor 10. Then, the resin composition containing an ethylene propylene rubber is extruded so that the outer periphery of the conductor 10 may be coat | covered with an extruder, and the insulating layer 11 of predetermined thickness is formed. Subsequently, the above-described silane crosslinkable composition is extruded with a predetermined thickness to form a sheath 12 so as to cover the outer periphery of the insulating layer 11. Thereafter, the sheath 12 is exposed to, for example, an environment at a temperature of 80 ° C. and a relative humidity of 90% to react with moisture, thereby silane cross-linking the silane crosslinkable composition forming the sheath 12.

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, although cable 1 was explained to an example as an electric wire cable, the present invention is not limited to this, but it may constitute as an electric insulated wire provided with an insulating layer as a covering layer. In this case, as in the case of forming the sheath 12 in the above-described embodiment, it is preferable that the silane crosslinkable composition be extruded on the outer periphery of the conductor to form an insulating layer, and the insulating layer be contacted with water for silane crosslinking.

  Moreover, although the above-mentioned embodiment demonstrated the case where the cable 1 was equipped with one electric wire by which the insulating layer was provided in the outer periphery of the conductor, the cable 1 is the twisted wire which twisted two or more electric wires. You may have.

  Next, an embodiment of the present invention will be described.

  The materials used in Examples and Comparative Examples are as follows.

· Chlorinated polyethylene (Mooney viscosity (ML 1 + 4) at 121 ° C .: 55, heat of fusion: less than 1.0 J / g): "CM 352 L" manufactured by Hangzhou Chemical Industrial Co., Ltd.
-Hydrotalcite: "Mag Celler 1" manufactured by Kyowa Chemical Industry Co., Ltd.
-Epoxidized soybean oil: "Newsizer 510R" manufactured by NOF Corporation
・ Peroxide (dicumyl peroxide): Nippon Oil and Fats Co., Ltd. “DCP”
Silane compound (3-methacryloxypropyltrimethoxysilane): "KBM-503" manufactured by Shin-Etsu Chemical Co., Ltd.
Silane compound (3-methacryloxypropyl triethoxysilane): "KBE-503" manufactured by Shin-Etsu Chemical Co., Ltd.
・ Plasticizer (chlorinated paraffin): "EMPARA 40" manufactured by Ajinomoto Fine Techno Co., Ltd.
・ Plasticizer (di-2-ethylhexyl phthalate): Shin Nippon Rika Co., Ltd. “San Soathea DOP”
・ Plasticizer (Diisononyl Phthalate): Shin Nippon Rika Co., Ltd. “San Soathea DINP”
・ Plasticizer (paraffin-based process oil, carbon atom ratio in component; paraffin / naphthene / aromatic = 68/28/4): Nippon Sun Oil Co., Ltd. "Sanper 115"
・ Plasticizer (naphthene process oil, carbon atom ratio in component; paraffin / naphthene / aromatic = 49 / 35.5 / 15.5): "NP-24" manufactured by Idemitsu Kosan Co., Ltd.
・ Plasticizer (aromatic process oil, carbon atom ratio in component; paraffin / naphthene / aromatic = 20/32/48): Fuji Kosan Co., Ltd. "Aromax # 1"
・ Flame retardant (antimony trioxide): Sumitomo Metal Mining Co., Ltd. "antimony trioxide"
Carbon (FEF carbon black): "Asahi Carbon 60G" manufactured by Asahi Carbon Co., Ltd.
Lubricant (polyethylene wax (PE wax, molecular weight: 2800)): Mitsui Chemicals Co., Ltd. "High Wax NL-200"
-Lubricant (ethylene bis oleic acid amide): Nippon Kasei Co., Ltd. "Suripax-O"
-Phenolic antioxidant (4,4'-thiobis (3-methyl-6-tert-butylphenol)): "NOCLAK 300R" manufactured by Ouchi Shinko Chemical Co., Ltd.
-Amine antioxidant (2,2,4-trimethyl-1,2-dihydroquinoline polymer): "NOCRACK 224" manufactured by Ouchi Shinko Chemical Co., Ltd.
· Silanol condensation catalyst (dioctyltin dineodecanoate): "Neostan U-830" manufactured by Nitto Kasei Co., Ltd.

(1) Preparation of Silane Crosslinkable Composition <Example 1>
First, an additive such as a plasticizer was added to the base polymer.
Specifically, first, as shown in Table 1 below, 100 parts by mass of chlorinated polyethylene, 6 parts by mass of hydrotalcite as a stabilizer, and epoxidized soybean oil as a stabilizer in a pressurized kneader 6 parts by mass, 3 parts by mass of PE wax as a lubricant, 1 part by mass of ethylene bis oleic acid amide as a lubricant, 40 parts by mass of carbon, nonmineral oil chlorinated paraffin as a plasticizer Ten parts by mass were charged, and the mixture was kneaded for 5 minutes at a blade rotational speed of 20 rpm. At this time, the kneader tank was not particularly heated, and the temperature of the kneaded material was raised to about 100 ° C. due to the heat generation of the rubber component.

Then, the silane compound and the peroxide were added to the said kneaded material.
A silane mixture in which 0.5 parts by mass of dicumyl peroxide as a peroxide is dissolved in 3.35 parts by mass of 3-methacryloxypropyltrimethoxysilane as a silane compound is charged into the above-mentioned pressurized kneader, The mixture was further kneaded for 5 minutes at a blade rotation number of 20 rpm. The temperature of the kneaded product after kneading was about 110 ° C.

Subsequently, the above-mentioned kneaded material was subjected to a silane grafting process using a single screw extruder 100 shown in FIG.
Specifically, the kneaded material was continuously supplied from the hopper 101 of the single-screw extruder 100 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 kneaded product was softened and kneaded by heating with the cylinders 103a and 103b, thereby graft copolymerizing a silane compound to chlorinated polyethylene. Thus, a silane-grafted chlorinated polyethylene was formed to obtain a silane crosslinkable composition containing the same. Thereafter, the silane crosslinkable composition was delivered to the head portion 104 of the extruder 100, and the strand 20 (150 cm in length) of the silane crosslinkable composition 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 form pellets 21 made of a silane crosslinkable composition. Then, in order to prevent mutual adhesion of the pellets 21, 1 part by mass of talc was dusted on the pellets 21 to obtain the compound of Example 1.
In the silane grafting process, a 40 mm single-screw single-screw extruder 100 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. Further, as the screw 102, a full flight shape and a compression ratio of 2.0 was used. The rotation speed of the screw 102 was 20 rpm. Further, as the die 105, a die having a hole diameter of 5 mm and a hole number of 3 was used.

Subsequently, separately from the above compound, a masterbatch containing an antioxidant and a silanol condensation catalyst was prepared.
Specifically, a pressurized kneader, 100 parts by mass of chlorinated polyethylene, 6 parts by mass of hydrotalcite as a stabilizer, 6 parts by mass of epoxidized soybean oil as a stabilizer, and a phenolic antioxidant 0.08 parts by mass of the agent, 1.5 parts by mass of the amine antioxidant, and 2 parts by mass of the silanol condensation catalyst were added, and the mixture was kneaded for 10 minutes at a blade rotational speed of 20 rpm. Then, the kneaded material was continuously supplied to the single-screw extruder 100 shown in FIG. 2, kneaded under the same conditions as above, extruded into a strand shape, and pelletized to obtain master batch pellets. In the pressure kneader, the temperature of the kneaded product was raised to 100 ° C. due to the heat generation of the rubber component.

  Finally, the silane-crosslinkable composition of Example 1 was prepared by adding the pellet-like masterbatch to the pellet-like compound and dry blending. At this time, the masterbatch was added to the compound at a ratio such that the masterbatch was 2.5 parts by mass with respect to 100 parts by mass of chlorinated polyethylene in the compound.

<Examples 2 and 3>
In Examples 2 and 3, as shown in Table 1, the type of plasticizer contained in the silane crosslinkable composition was changed from chlorinated paraffin to di-2-ethylhexyl phthalate or diisononyl phthalate. A silane crosslinkable composition was prepared as in 1 and a cable was made.

Example 4
In Example 4, the type of silane compound is changed from 3-methacryloxypropyltrimethoxysilane to 3-methacryloxypropyltriethoxysilane, except that the compounding amount is changed from 3.35 parts by mass to 3.92 parts by mass. Then, a silane crosslinkable composition was prepared in the same manner as in Example 1 to prepare a cable.

Comparative Example 1
In Comparative Example 1, a silane crosslinkable composition was prepared in the same manner as in Example 1 except that no plasticizer was added, and a cable was produced.

<Comparative Examples 2 to 4>
In Comparative Examples 2 to 4, a silane crosslinkable composition was prepared in the same manner as in Example 1 except that the type of plasticizer was changed from non-mineral oil type to mineral oil type, and a cable was produced. As a mineral oil-based plasticizer, a paraffin-based process oil was used in Comparative Example 2, a naphthene-based process oil in Comparative Example 3, and an aromatic-based process oil in Comparative Example 4.

(2) Production of Cable Next, the cables 1 of Examples 1 to 4 and Comparative Examples 1 to 4 were produced by extruding the prepared silane crosslinkable composition by the single-screw extruder 100 shown in FIG. Specifically, a copper conductor having a cross-sectional area of 8 mm 2 is inserted as the conductor 10 into the die 105 of the single screw extruder 100, and an ethylene propylene rubber (EP rubber) is extruded around the outer periphery to insulate the thickness 1.0 mm. While forming the layer 11, the cable 1 was produced by extruding the above-mentioned silane crosslinkable composition on the outer periphery of the insulating layer 11 to form a sheath 12 with a thickness of 1.7 mm. Thereafter, the cable 1 was stored in a constant temperature and humidity chamber at a temperature of 60 ° C. and a relative humidity of 95% for 24 hours to perform silane crosslinking treatment.
In addition, in preparation of the cable 1, the 20-mm single-screw single-screw extruder 100 was used. Further, the ratio L / D of the screw diameter D to the screw length L was set to 15. The temperature of the cylinder 103a is 120 ° C., the temperature of the cylinder 103 b is 150 ° C., the temperature of the crosshead portion 110 is 150 ° C., the temperature of the neck 109 is 150 ° C., and the temperature of the die 105 is 130 ° C. In addition, the rotation speed of the screw 102 was 15 rpm, and the screw 102 had a full flight shape and a compression ratio of 2.0.

(3) Evaluation method About the produced cable, it evaluated by the following methods.

(With or without bleed)
The presence or absence of the bleed was visually observed for the surface appearance of the cable, and was rated as "good" if the plasticizer did not bleed out, or as "poor" if the bleed out was confirmed.

(Gel fraction after crosslinking)
In order to evaluate the degree of crosslinking of the sheath, the gel fraction of the sheath after silane crosslinking was measured.
First, 0.5 g of a sample was taken from the sheath after silane crosslinking, and this sample was placed in a 40 mesh brass wire mesh. Subsequently, the sample was extracted with xylene in an oil bath at 110 ° C. After the extraction process, the remaining sample was removed from xylene and vacuum dried at 80 ° C. for 4 hours. Then, the mass of the remaining sample after drying was weighed, and the gel fraction R of the sample was calculated from the mass a of the sample before extraction with xylene and the mass b of the remaining sample after extraction with xylene by the following equation.
R (%) = b / a × 100
In this example, the case where the gel fraction after crosslinking is 70% or more is regarded as pass “o”, and the case where the gel fraction is less than 70% is regarded as rejection “x”.

(Tensile elongation)
In order to evaluate the flexibility of the sheath, the tensile elongation of the sheath was measured.
First, the sheath was peeled off from the cable, the sheath was punched out with a No. 6 dumbbell to prepare a test sample, and the test sample was pulled at a tensile speed of 500 mm / min to measure the tensile elongation. In this example, if the tensile elongation is 350% or more, the pass "○", and if it is less than 350%, the fail "×".

(Oil resistance)
The oil resistance of the sheath was determined using the test lubricant No. 1 specified in JIS K6258. The sheath was heated in oil at 120 ° C. for 18 hours using No. 2 (IRM No. 902 oil), and the percentage of tensile strength remaining before and after heating was determined. In this example, if the tensile strength residual ratio of the sheath after the oil resistance test is 60% or more, it is regarded as pass "o", and if less than 50%, it is considered as rejection "x".

(4) Evaluation result The evaluation result about each Example and comparative example is shown in Table 1.

In Examples 1 to 4, it was confirmed that the plasticizer was not bled on the surface of the sheath. Further, it was confirmed that the gel fraction was 70% or more in all cases, and the degree of crosslinking of the sheath was high. In addition, since the plasticizer was present in the sheath without bleeding, it was confirmed that the tensile elongation was at least 350% in each case, and the flexibility was excellent. Moreover, since the sheath had a high degree of crosslinking, it was confirmed that the sheath was excellent in oil resistance.
In Examples 1 and 4, since chlorinated paraffin was used as the non-mineral oil plasticizer, it was confirmed that the degree of crosslinking and oil resistance were higher than in Examples 2 and 3 in which phthalic acid esters were used. It is presumed that this is because chlorinated paraffin is incorporated into the silane crosslinked product at the time of silane crosslinking to contribute to the improvement of the degree of crosslinking.

  In Comparative Example 1, since no plasticizer was added, it was confirmed that graft copolymerization of the silane compound was not inhibited by the plasticizer, and a high degree of crosslinking and oil resistance were obtained. It was also confirmed that no bleeding of the plasticizer occurred. However, since no plasticizer was added, it was confirmed that the sheath had a small tensile elongation and could not obtain sufficient flexibility.

  In Comparative Example 2, since paraffin-based process oil was used as the plasticizer, it was confirmed that the plasticizer bleeds on the surface of the sheath. The reason for this is that paraffinic process oils have high aniline points and low compatibility with rubbers having polarity.

  In Comparative Examples 3 and 4, since naphthene type or aromatic type was used as the plasticizer, the graft copolymerization of the silane compound is inhibited by the plasticizer and the degree of crosslinking is lowered, and the oil resistance is accordingly lowered. Was confirmed. In addition, it was confirmed that the naphthene type and aromatic type do not bleed since compatibility with the component having polarity is not as low as paraffin type.

  When Comparative Examples 2 to 4 are compared, it is confirmed that the degree of crosslinking decreases as the amount of the aromatic component contained in the mineral oil-based plasticizer increases, and the oil resistance decreases accordingly. This is presumed to be that when the silane compound is graft copolymerized, the aromatic component contained in the plasticizer inhibits the reaction and the grafting rate decreases.

<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:
A conductor and a covering layer covering an outer periphery of the conductor;
The coating layer is formed by crosslinking a silane crosslinkable composition,
The above-mentioned silane crosslinkable composition provides a wire cable comprising a base polymer comprising silane-grafted chlorinated polyethylene obtained by graft copolymerizing a silane compound to chlorinated polyethylene and a non-mineral oil plasticizer.

[Supplementary Note 2]
In the wire cable according to Appendix 1, preferably
The non-mineral oil plasticizer is at least one of chlorinated paraffin and phthalic acid ester plasticizers.

[Supplementary Note 3]
In the wire cable of Supplementary Note 1 or 2, preferably
The compounding quantity of the said non-mineral oil type plasticizer is 1 to 30 mass parts with respect to 100 mass parts of said chlorinated polyethylene.

[Supplementary Note 4]
In the wire cable according to any one of appendices 1 to 3, preferably
The silane compound has a methacryl group.

[Supplementary Note 5]
In the cable according to appendix 4, preferably
The silane compound is at least one of 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-methacryloxypropylmethyldimethoxysilane and 3-methacryloxypropylmethyldiethoxysilane.

1 Cable 2 Insulated wire 10 Conductor 11 Insulating layer 12 Coating layer (sheath)

Claims (14)

Adding a non-mineral oil plasticizer, a silane compound and a peroxide to a chlorinated polyethylene consisting of a base polymer to obtain a mixture;
Grafting the silane compound onto the chlorinated polyethylene in the presence of the peroxide by heating and kneading the mixture to obtain a silane crosslinkable composition;
Contacting the silane-crosslinkable composition with water to obtain a silane-crosslinked product ;
The manufacturing method of the silane crosslinked material whose said non-mineral oil type plasticizer is at least one of chlorinated paraffin and phthalate ester plasticizers. The amount of non-mineral oil plasticizer is 30 parts by mass 1 part by mass or more with respect to the chlorinated polyethylene 100 parts by weight, the production method of the silane-crosslinked product of claim 1. The manufacturing method of the silane crosslinked material of Claim 1 or 2 in which the said silane compound has a methacryl group. The silane compound is 3-methacryloxypropyl trimethoxy silane, 3-methacryloxypropyl triethoxysilane, at least one of 3-methacryloxypropyl methyl dimethoxy silane and 3-methacryloxypropyl methyl diethoxy silane, claim 1 The manufacturing method of the silane crosslinked material as described in 4. Adding a non-mineral oil plasticizer to a chlorinated polyethylene consisting of a base polymer and then adding a silane compound and a peroxide to obtain a mixture;
Grafting the silane compound onto the chlorinated polyethylene in the presence of the peroxide by heating and kneading the mixture to obtain a silane crosslinkable composition;
Extruding the silane crosslinkable composition onto a conductor coated insulating layer to form a sheath;
Contacting the sheath with water for silane crosslinking. The method for producing a cable according to claim 5 , wherein the non-mineral oil plasticizer is at least one of chlorinated paraffin and phthalate plasticizers. The manufacturing method of the cable of Claim 5 or 6 whose compounding quantity of the said non-mineral oil type plasticizer is 1 to 30 mass parts with respect to 100 mass parts of said chlorinated polyethylene. The manufacturing method of the cable in any one of Claims 5-7 in which the said silane compound has a methacryl group. The silane compound is 3-methacryloxypropyl trimethoxy silane, 3-methacryloxypropyl triethoxysilane, at least one of 3-methacryloxypropyl methyl dimethoxy silane and 3-methacryloxypropyl methyl diethoxy silane, claim 8 The manufacturing method of the cable as described in. Adding a non-mineral oil plasticizer to a chlorinated polyethylene consisting of a base polymer and then adding a silane compound and a peroxide to obtain a mixture;
Grafting the silane compound onto the chlorinated polyethylene in the presence of the peroxide by heating and kneading the mixture to obtain a silane crosslinkable composition;
Extruding the silane crosslinkable composition onto a conductor to form an insulating layer;
Contacting the insulating layer with water to crosslink the silane, and manufacturing the wire. The method according to claim 10 , wherein the non-mineral oil plasticizer is at least one of chlorinated paraffin and phthalate plasticizers. The manufacturing method of the electric wire of Claim 10 or 11 whose compounding quantity of the said non-mineral oil type plasticizer is 1 to 30 mass parts with respect to 100 mass parts of said chlorinated polyethylene. The manufacturing method of the electric wire in any one of Claims 10-12 in which the said silane compound has a methacryl group. The silane compound is 3-methacryloxypropyl trimethoxy silane, 3-methacryloxypropyl triethoxysilane, at least one of 3-methacryloxypropyl methyl dimethoxy silane and 3-methacryloxypropyl methyl diethoxy silane, claim 10 The manufacturing method of the electric wire as described in.

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