JP7157540B2 - Wiring material - Google Patents

Description

The present invention relates to a wiring material having an aluminum conductor.

For wiring materials such as insulated wires, cables, cords, optical fiber core wires, optical fiber cords, etc. used for internal and external wiring of electrical and electronic equipment, materials for insulating coating layers or sheaths are selected according to the application. . For example, when heat resistance is required, the insulating coating layer or sheath of the wiring material is usually made of heat-resistant resin or crosslinked resin (for example, crosslinked polyvinyl chloride or crosslinked polyethylene). Conventionally, as such wiring materials, those having an insulating coating layer made of crosslinked polyvinyl chloride or the like on the outer periphery of a copper wire as a conductor, and those having a sheath made of crosslinked polyethylene or the like have been widely used.
CV cables (cross-linked polyethylene insulated vinyl sheath cables) with cross-linked polyethylene for the insulation coating layer and PVC resin (polyvinyl chloride) for the sheath are generally used as power cables and distribution cables.
On the other hand, from the viewpoint of scarcity of resources, cost and weight reduction, wiring materials using conductors made of aluminum (aluminum conductors) are used instead of copper conductors in electric power and power distribution fields. (see, for example, Patent Document 1).

JP 2017-143645 A

However, aluminum has a lower electrical conductivity than copper, so the diameter of the conductor must be thicker to allow the same current to flow. Furthermore, aluminum conductors are hard and have many problems such as being easily broken if scratched. A CV cable using such an aluminum conductor becomes hard when wired, so that the cable may bounce during wiring, making it difficult to wire (less flexible).
In addition, in conventional CV cables, it is difficult to peel the insulating coating layer from the conductor, and in particular, CV cables using aluminum conductors, which have the above problem, are required to be improved in stripping processability. In other words, the aluminum conductor is easily damaged during the peeling process, and there is a risk that the aluminum conductor will break if the process is not carried out carefully. Furthermore, in the peeling process, linear bodies or hair-like bodies (sometimes referred to as whiskers) of the insulating coating layer may remain on the cut end surface of the insulating coating layer. If such whiskers remain, the whiskers will bite into the connector when the connector is processed, resulting in poor contact.
In addition, since the aluminum conductor is very vulnerable to scratches, the blade cannot be deeply cut into the insulating coating layer when it is peeled off. Conventional cross-linked polyethylene cannot be peeled unless the blade is sufficiently inserted, and even in that case, whiskers tend to remain. This whisker must be removed in post-processing. Therefore, if the coating is stripped without inserting the blade too much, the productivity is greatly improved.

INDUSTRIAL APPLICABILITY The present invention provides a wiring material that is excellent in peelability (ease of processing when peeling an insulating coating layer, also referred to as peelability) while ensuring flexibility even when an aluminum conductor is used as a conductor. The task is to

The present inventors have found that by forming an insulating coating layer directly provided on the outer periphery of an aluminum conductor with a layer of a base resin containing at least one of ethylene rubber and styrene elastomer, the resulting wiring material has flexibility. and excellent peeling workability can be imparted. Based on this knowledge, the present inventors have made further studies and completed the present invention.

That is, the objects of the present invention have been achieved by the following means.
<1> A wiring material having at least one insulating coating layer on the outer periphery of an aluminum conductor,
Among the insulating coating layers, the innermost insulating coating layer provided directly on the outer circumference of the aluminum conductor is
A wiring material which is a layer of a cured silanol condensation product of the following silane crosslinkable composition .
<Silane crosslinkable composition>
It is selected from ethylene-α-olefin copolymer resins, polyethylene, polypropylene, and polyolefin copolymer resins having an acid copolymer component, which are grafted with at least one of ethylene rubber and styrene elastomer and a silane coupling agent. Silane crosslinkable composition containing at least one silane graft resin and a silanol condensation catalyst
<2> The wiring material according to <1> , wherein the total content of the ethylene rubber and the styrene-based elastomer in the base resin is at least 5% by mass.
<3> The wiring material according to <1> or <2> , wherein the base resin contains an organic mineral oil.
<4> The wiring member according to any one of <1> to <3> , wherein the insulating coating layer has two or more layers, and the outermost insulating coating layer is a polyvinyl chloride insulating coating layer.

In the present specification, a numerical range represented by "to" means a range including the numerical values before and after "to" as lower and upper limits.

The wiring material of the present invention, even if an aluminum conductor is used as the conductor, has both flexibility and excellent peelability, and can also achieve weight reduction.

[Wiring material]
The wiring material of the present invention has at least one insulating coating layer on the outer periphery of the aluminum conductor. Of the at least one insulation coating layer (hereinafter sometimes simply referred to as a coating layer), the innermost insulation coating layer provided directly on the outer periphery of the aluminum conductor is a base containing at least one of ethylene rubber and styrene elastomer It is made up of layers of resin.
The base resin layer is a polyolefin copolymer having at least one of ethylene rubber and styrene elastomer, ethylene-α-olefin copolymer, polyethylene, polypropylene and acid copolymerization component (including acid ester copolymerization component). A base resin layer containing at least one resin selected from the group consisting of (hereinafter referred to as an ethylene-based component-containing resin) is preferred. In this case, the innermost insulating coating layer may be a layer made of a non-crosslinked base resin, but is preferably a layer made of a crosslinked base resin in terms of heat resistance. Here, the crosslinked product of the base resin means a crosslinked product obtained by cross-linking the ethylene-based component-containing resin among the resins contained in the base resin (the ethylene-based component-containing resin becomes the crosslinked resin). The ethylene-based component-containing resin to be crosslinked may be the total amount or a part of the ethylene-based component-containing resin to be used, and can be appropriately determined depending on the application and the like. In the crosslinked product of the base resin, the ethylene rubber and the styrene elastomer are usually not crosslinked with other resins, but they may be crosslinked to the extent that the effects of the present invention are not impaired. As the method for cross-linking the ethylene-based component-containing resin, known resin cross-linking methods (e.g., electron beam cross-linking, cross-linking agents, chemical cross-linking methods using a cross-linking catalyst, etc.) can be applied without particular limitations. The silane cross-linking method, which will be described later, is preferable because it does not require a

In the present invention, "provided directly on the outer circumference of the aluminum conductor" means that the outer circumference of the aluminum conductor is in contact with the outer circumference of the aluminum conductor without an adhesive layer, a primer layer, or another layer such as an insulating coating layer interposed therebetween. means that it is set with

The details of why the wiring material having the aluminum conductor and the innermost insulating coating layer formed of the base resin layer has both flexibility and excellent peelability are not yet clear, but the following is considered. .
That is, the crosslinked polyethylene coated on the outside of the aluminum conductor, which is a conventional structure, is integrated with the aluminum conductor, thereby increasing the hardness of the aluminum conductor. Moreover, since the aluminum conductor has a smaller conductor resistance and a smaller allowable current than the copper conductor, it is usually increased in size (increased in diameter), so that the wiring material itself becomes hard. Furthermore, the crosslinked polyethylene layer is hard and difficult to insert with a blade, and since the material is stretched, it cannot be peeled unless the blade is inserted into the vicinity of the conductor.
However, in the wiring material of the present invention, by forming the portion (innermost insulating coating layer) in direct contact with the aluminum conductor with a layer of base resin, the hardness of the aluminum conductor is alleviated and the stress acting during wiring is reduced. It is also possible to reduce the repulsion of the wiring material against. Specifically, when cutting the coating layer, even if the blade is not inserted to the limit of the aluminum conductor, the coating layer can be peeled off (cut, removed) without leaving whiskers that cause an increase in contact resistance. ). Moreover, since aluminum has a small specific gravity, it is possible to reduce the weight of the wiring material provided with the copper conductor.
Furthermore, as a preferred embodiment of the wiring material of the present invention, the innermost insulating coating layer is formed of a layer made of a cured product of a base resin, and further a layer made of a cured silanol condensation product of a silane crosslinkable composition described later. And the cured product, especially the silanol condensation cured product, has excellent short-term heat resistance (for example, against instantaneous high temperature in the environmental atmosphere) and is difficult to melt, and long-term (for example, continuous or intermittent high temperature in the environmental atmosphere). It is also possible to improve the heat resistance against quenching, and it is possible to reduce the diameter of the wiring material.

Since the wiring material of the present invention exhibits excellent peelability, it is a wiring material before being peeled (unpeeled), and the coating layer can be formed as desired due to the excellent peelability. is the wiring material after the is removed (skinned).

The insulated wire that can be used as the wiring material of the present invention may be an electric wire having at least one insulating coating layer on the outer periphery of the aluminum conductor, and the aluminum conductor may be a single wire or an aluminum stranded wire described later.
The cable that can be used as the wiring material of the present invention usually has two or more insulating coating layers on the outer periphery of the aluminum conductor, and the outermost insulating coating layer ( The outermost insulating coating layer) surrounds the aluminum conductor and other insulating coating layers. For example, there is a cable in which one or a plurality of insulated wires having an innermost insulating coating layer on the outer circumference of an aluminum conductor are collectively surrounded by an outermost insulating coating layer called a sheath. When this cable has a plurality of insulated wires, the plurality of insulated wires may be arranged in parallel, or may be arranged in a twisted manner (stranded wire). When twisting the insulated wires, the number of insulated wires, the arrangement of the insulated wires, the twisting direction, the twisting pitch, and the like can be appropriately set according to the application.

The diameter of the wiring material can be appropriately determined according to the application and the like, and is not particularly limited. For example, when used as an insulated wire, the thickness is preferably 0.8 to 35 mm, more preferably 1 to 30 mm, in terms of strength and flexibility. When used as a cable, the thickness is preferably 0.8 to 50 mm, more preferably 1 to 35 mm, in terms of strength and flexibility.

The wiring material of the present invention is mainly used as a substitute electric wire or cable for a CV cable, which is a power distribution cable, and is also suitable for cabtyre cables, cords, railway cables, solar and wind power generation cables, aircraft cables, etc. used for

<Aluminum conductor>
The aluminum conductor used in the present invention is not particularly limited as long as it is a conductor made of aluminum. It is also called.).

As the aluminum wire, those conventionally used for wiring materials can be used, and for example, a wire made of (pure) aluminum or an aluminum alloy can be used. Examples of aluminum alloys include, but are not limited to, 1000 series aluminum alloys, 2000 series aluminum alloys, 3000 series aluminum alloys, 4000 series aluminum alloys, 5000 series aluminum alloys, and 6000 series aluminum alloys. , Fe is 0.6% by mass or less, Si is 0.2 to 1.0% by mass, Mg is 0.2 to 1.0% by mass, and the balance is aluminum and inevitable impurities. be done.
Among aluminum and aluminum alloys, 1000 series aluminum alloys having an aluminum purity of 99% or more are preferable, and those having high electrical conductivity are preferable.
The cross-sectional shape of the aluminum wire can be appropriately determined according to the application, and examples thereof include round (circular), flat (rectangular), hexagonal, and the like. In the present invention, a circular cross-section is preferred, for example, because it facilitates the formation of a stranded wire.

The number of aluminum wires forming the stranded wire is not particularly limited as long as it is plural (two or more).
The arrangement, twisting direction, twisting pitch, and the like of the aluminum wires when the aluminum wires are twisted can be appropriately set according to the application.
In order to reduce the outer diameter of the stranded aluminum wire, it is preferable to use a rolled conductor that is further drawn by a die or the like after being stranded.

The outer diameter of the aluminum wire can be appropriately determined according to the application, etc., but in terms of strength and flexibility, it is preferably 0.15 to 3.5 mm, more preferably 0.3 to 3 mm, and 0.3 mm to 3 mm. 0.35 to 2.5 mm is more preferred.
The outer diameter of the aluminum stranded wire can be appropriately determined according to the application and the like. preferable. The outer diameter of the stranded aluminum wire is the diameter of an imaginary circumscribed circle circumscribing the outer peripheral surfaces of the plurality of aluminum wires arranged on the outer side in a cross section perpendicular to the axis of the stranded wire. The outer diameter and conductor cross-sectional area of the aluminum stranded wire are determined by the allowable current. Although the thinner the aluminum wire diameter per wire, the better the flexibility, the core wire (wire) is more likely to break. From this point of view, the wire diameter is particularly preferably about 0.3 to 1 mm.

<Insulating layer>
The insulating coating layer provided on the outer periphery of the aluminum conductor functions as an insulating layer and has a single-layer structure or a multi-layer structure.
When the insulating coating layer is a single layer, this insulating coating layer becomes the innermost insulating coating layer provided in direct contact with the outer circumference of the aluminum conductor.
On the other hand, when the insulating coating layer has a multi-layer structure (referred to as a multi-layer insulating coating layer), the number of constituent layers constituting the multi-layer insulating coating layer can be appropriately determined according to the application. , preferably 2 to 5 layers, more preferably 2 or 3 layers. In particular, when the wiring material is a cable, the insulating coating layer is preferably a multilayer insulating coating layer, and the outermost constituent layer (outermost insulating coating layer) in the multilayer insulating coating layer functions as a sheath. . In the multilayer insulating coating layer, it is preferable that the constituent layers are directly laminated without interposing another layer such as an adhesive layer.
In the present invention, for convenience, a wiring material having a single insulating coating layer (innermost insulating coating layer) is referred to as an insulated wire, and a wiring material having a multilayer insulating coating layer, particularly an outermost insulating coating layer (sheath) is referred to as a cable. However, as described above, even an insulated wire includes a form having a multilayer insulation coating layer.

In the present invention, when layers formed of the same material (ingredients and content) are laminated to form the insulating coating layer, these layers are counted as one layer. On the other hand, even if the material forming the insulating coating layer is the same material, if they are not laminated adjacently, that is, if they are laminated via another layer, each layer is counted as one layer. do. Also, when layers formed of different materials forming the insulating coating layer are stacked, each layer is counted as one layer regardless of whether or not they are adjacent.

- Innermost insulating coating layer -
The innermost insulating coating layer (hereinafter sometimes simply referred to as the innermost coating layer) is formed of a layer of a base resin to be described later, preferably a layer of a cured product of the base resin, and more preferably a layer of a cured product of the base resin. It is formed of a layer of a cured silanol condensation product (sometimes referred to as a cured product layer) obtained by subjecting a silane crosslinkable composition to a silanol condensation reaction. This cured product layer is a silane crosslinkable composition containing at least one of an ethylene rubber and a styrene elastomer, a silane graft resin, and a silanol condensation catalyst. It is crosslinked by hydrolyzing the groups and then subjecting them to a silanol condensation reaction.

- Outermost insulating coating layer -
The outermost insulating coating layer (simply referred to as the outermost coating layer or surface layer) is made of a known resin used for wiring materials, and examples thereof include thermoplastic resins and thermosetting resins described later.

- Intermediate insulating coating layer -
When the insulating coating layer is a multi-layer insulating coating layer having three or more layers, the intermediate insulating coating layer provided between the innermost coating layer and the outermost coating layer is made of a known resin used for wiring materials, Examples thereof include thermoplastic resins and thermosetting resins, which will be described later.

- Thickness of insulating coating layer -
The thickness of the insulating coating layer can be appropriately determined according to the diameter of the wiring material, the application, and the like. For example, the total thickness of the coating layer (in the case of a multi-layer coating layer, the total thickness of each component layer) is preferably 0.2 to 10 mm, and 0.2 to 10 mm in terms of heat resistance, dielectric strength, strength and flexibility. 6 to 5 mm is more preferred.
The thickness of each constituent layer can also be appropriately determined according to the total thickness of the coating layers, the diameter of the wiring material, the application, and the like. For example, when used as an insulated wire, the thickness of the innermost coating layer is preferably 0.2 to 5 mm, more preferably 0.5 to 4 mm, and when used as a cable, preferably 0.4 to 5 mm. , 0.5 to 3 mm. In the present invention, the thickness of the innermost coating layer is the difference (the thinnest thickness) between the outer diameter of the aluminum conductor and the outer diameter of the innermost coating layer. The thickness of the outermost coating layer is, for example, preferably 0.2 to 5 mm, more preferably 0.5 to 4 mm. The (total) thickness of the intermediate insulating coating layer is preferably 0 to 5 mm, for example.

[Method for manufacturing wiring material]
First, each component used in the method of manufacturing the wiring material will be described.
<Aluminum conductor>
A commercially available aluminum conductor may be used as the aluminum conductor used in the present invention. The aluminum stranded wire may be produced by twisting commercially available aluminum wires by a known method.

<Base resin>
The base resin used in the present invention contains at least one of ethylene rubber and styrene elastomer. By containing at least one of ethylene rubber and styrene-based elastomer in the base resin, the balance with the strength of the aluminum conductor can be improved.
The base resin preferably contains an ethylene-based component-containing resin in addition to the ethylene rubber and the styrene-based elastomer. The base resin may contain other resins than ethylene rubber, styrene-based elastomers, and ethylene-based component-containing resins, and may further contain other resins, organic mineral oils, plasticizers, etc. good too.

(ethylene rubber)
Ethylene rubber is not particularly limited as long as it is a copolymer rubber of ethylene and α-olefin. For example, ethylene rubber is preferably a binary copolymer rubber of ethylene and α-olefin (preferably having 1 to 12 carbon atoms), ethylene and α-olefin (preferably having 1 to 12 carbon atoms) and α- A rubber composed of a terpolymer with a third component having an unsaturated bond other than an olefin may be mentioned. The third component includes conjugated or non-conjugated dienes, specifically butadiene, isoprene, 1,3-pentadiene, 2,3-dimethyl-1,3-butadiene, dicyclopentadiene (DCPD), ethylidene norbornene (ENB), 1,4-hexadiene and the like. Binary copolymer rubbers include ethylene-propylene rubber (EPM), and terpolymer rubbers include ethylene-propylene-diene rubber (EPDM).
Ethylene rubber may be used alone or in combination of two or more.

(Styrene-based elastomer)
Styrene-based elastomers refer to those having an aromatic vinyl compound as a constituent component in the molecule. Examples of such styrene-based elastomers include block copolymers and random copolymers of conjugated diene compounds and aromatic vinyl compounds, or hydrogenated products thereof. Examples of such styrene-based elastomers include styrene-ethylene-butylene-styrene block copolymer (SEBS), styrene-isoprene-styrene block copolymer (SIS), hydrogenated SIS, styrene-butadiene-styrene block copolymer. polymer (SBS), hydrogenated SBS, styrene-ethylene-ethylene-propylene-styrene block copolymer (SEEPS), styrene-ethylene-propylene-styrene block copolymer (SEPS), styrene-butadiene rubber (SBR), Examples include hydrogenated styrene-butadiene rubber (HSBR).
Styrenic elastomers may be used alone or in combination of two or more.

(Resin containing ethylene-based component)
The ethylene-based component-containing resin preferably contained in the base resin has, in the presence of radicals generated from an organic peroxide described later, a graft reaction site of a silane coupling agent and a site capable of graft reaction in or on the main chain. It has a terminal and can be condensed (crosslinked) by a silane crosslinking method. Examples of sites that can be grafted include unsaturated bond sites of carbon chains, carbon atoms having hydrogen atoms, and the like.
The ethylene-based component-containing resin is at least one resin selected from the group consisting of ethylene-α-olefin copolymers, polyethylene, polypropylene, and polyolefin copolymers having an acid copolymer component, and ethylene-α- It is preferably at least one resin selected from the group consisting of olefin copolymers, polyethylene and polypropylene.
The ethylene-based component-containing resin and each resin described below may be used alone or in combination of two or more.

- Polyethylene resin -
The polyethylene resin may be a polymer resin containing an ethylene component, and may be an ethylene homopolymer or a copolymer of ethylene and an α-olefin (preferably 5 mol % or less) (excluding polypropylene). ), and resins composed of copolymers of ethylene and non-olefins (preferably 1 mol % or less) having only carbon, oxygen and hydrogen atoms in functional groups. As the α-olefins and non-olefins mentioned above, known ones conventionally used as copolymerization components of polyethylene can be used without particular limitation.
Polyethylene resins include high density polyethylene (HDPE), low density polyethylene (LDPE), ultra high molecular weight polyethylene (UHMW-PE), linear low density polyethylene (LLDPE) and very low density polyethylene (VLDPE). Among them, low density polyethylene, linear low density polyethylene or ultra-low density polyethylene is preferable, and low density polyethylene or linear low density polyethylene is more preferable.

- Polypropylene resin -
The polypropylene resin may be a polymer resin containing propylene as a main component, such as a propylene homopolymer (homopolypropylene resin), an ethylene-propylene random copolymer, an ethylene-propylene block copolymer, and the like. can be used.

- Ethylene-α-olefin copolymer resin -
Ethylene-α-olefin copolymer resins preferably include resins of copolymers of ethylene and α-olefins having 3 to 12 carbon atoms (excluding those corresponding to the polyethylene and polypropylene described above). .

- Polyolefin copolymer resin having an acid copolymer component -
The acid copolymerization component (including the acid ester copolymerization component) in the polyolefin copolymer resin having an acid copolymerization component is not particularly limited, but may be a carboxylic acid compound such as (meth)acrylic acid, vinyl acetate, or Examples include acid ester compounds such as alkyl (meth)acrylates (preferably having 1 to 12 carbon atoms). Polyolefin copolymer resins having an acid copolymer component include, for example, ethylene-vinyl acetate copolymer (EVA), ethylene-(meth)acrylic acid copolymer, ethylene-alkyl(meth)acrylate copolymer, and the like. each resin of. Among them, ethylene-vinyl acetate copolymer, ethylene-methyl acrylate copolymer, ethylene-ethyl acrylate copolymer, and ethylene-butyl acrylate copolymer are preferable, because of their acceptability to inorganic fillers and heat resistance. Ethylene-vinyl acetate copolymer resin is more preferable from the viewpoint of properties.

The above polyolefin resins, particularly polyethylene resins, polypropylene resins, ethylene-α-olefin copolymer resins, and polyolefin copolymer resins having an acid copolymer component may each be acid-modified. The acid used for acid modification of these resins is not particularly limited as long as it is an acid commonly used for acid modification of resins, and examples thereof include unsaturated carboxylic acids.

(other resin)
Other resins that the base rubber may contain include resins used for insulating coating layers of wiring materials. Examples include acrylic rubber, polyester elastomer, polyamide elastomer and the like.

(organic mineral oil)
Organic mineral oils include aromatic oils, paraffinic oils, naphthenic oils, or mixed oils containing these three. As the organic mineral oil, those commonly used in resin compositions can be used without particular limitation, and paraffinic oils and naphthenic oils are preferred. One type of organic mineral oil may be used alone, or two or more types may be used in combination.

(Base resin content)
The total content of ethylene rubber and styrene elastomer in the base resin is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more. The lower limit of the total content is less than 100% by mass, preferably 70% by mass or less, more preferably 60% by mass or less.
The content of ethylene rubber or styrene-based elastomer in the base resin is appropriately set within a range that satisfies the above total content. For example, the content of ethylene rubber and styrene elastomer is preferably 5 to 40% by mass, more preferably 10 to 30% by mass. The content of the styrene-based elastomer is preferably 20% by mass or more from the viewpoint of peelability (suppression of whiskering).

The total content of the ethylene component-containing resin in the base resin is not particularly limited, but is preferably 30 to 95% by mass, more preferably 50 to 90% by mass, and even more preferably 55 to 85% by mass. This ethylene-based component-containing resin is preferably contained as a main component of the base resin (maximum content component in the base resin).
In the present invention, the content in the base resin of each of the resins included in the ethylene-based component-containing resin is appropriately set within a range that satisfies the above-mentioned content of the ethylene-based component-containing resin. Set to content rate. For example, the polyethylene resin content is preferably 0 to 95% by mass, more preferably 0 to 70% by mass. The polypropylene resin content is preferably 0 to 40% by mass, more preferably 2 to 30% by mass. The content of the ethylene-α-olefin copolymer resin is preferably 0 to 95% by mass, more preferably 0 to 70% by mass. The content of the polyolefin copolymer resin having an acid copolymer component is preferably 0 to 30% by mass, more preferably 0 to 10% by mass.

The content of other resins in the base resin can be appropriately set within a range that does not impair the effects of the present invention.
The content of the organic mineral oil in the base resin (when the base resin contains a plasticizer, the total content with the plasticizer) is not particularly limited, but is preferably 0 to 40% by mass.

<Inorganic filler>
The base resin layer can contain inorganic fillers.
The inorganic filler is not particularly limited as long as it is commonly used in conventional resin compositions.
When the layer of the base resin of the wiring material of the present invention is a silanol condensation cured product, the inorganic filler has, on its surface, a hydrolyzable silyl group of the silane coupling agent described later, a hydrogen bond, a covalent bond, or the like, or an intermolecular bond. Therefore, those having a site that can be chemically bonded are preferred. Examples of sites that can be chemically bonded to hydrolyzable silyl groups include OH groups (OH groups such as hydroxyl groups, water molecules containing water or water of crystallization, and carboxyl groups), amino groups, SH groups, and the like.
Examples of inorganic fillers include aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, calcium silicate, magnesium silicate, calcium oxide, magnesium oxide, aluminum oxide, aluminum nitride, aluminum borate whiskers, and hydrated aluminum silicate. , hydrated magnesium silicate, basic magnesium carbonate, hydrotalcite, talc, and other compounds having a hydroxyl group or water of crystallization. Boron nitride, silica (crystalline silica, amorphous silica, etc.), carbon, clay, zinc oxide, tin oxide, titanium oxide, molybdenum oxide, antimony trioxide, silicone compounds, quartz, zinc borate, white carbon, Also included are zinc borate, zinc hydroxystannate, zinc stannate and the like.
The inorganic filler preferably contains at least one selected from the group consisting of metal hydrates, silica, calcium carbonate and clay, more preferably at least one selected from this group.

The inorganic filler can also be used after being surface-treated with various surface-treating agents. Examples of magnesium hydroxide surface-treated with a silane coupling agent include Kisuma 5L and Kisuma 5P (both trade names, manufactured by Kyowa Chemical Industry Co., Ltd.).
An inorganic filler may be used individually by 1 type, and may use 2 or more types together.

When the inorganic filler is used as a powder, the average particle size is preferably 0.2 to 10 μm, more preferably 0.3 to 8 μm, even more preferably 0.4 to 5 μm, 0.4 to 3 μm is particularly preferred. When the average particle size of the inorganic filler is within the above range, it is possible to obtain a molded article having an appearance free of lumps by preventing secondary aggregation, and the bonding with the silane coupling agent is maintained to achieve sufficient cross-linking. can be formed. The average particle size of the inorganic filler is determined by dispersing the inorganic filler in alcohol or water and using an optical particle size analyzer such as a laser diffraction/scattering particle size distribution analyzer.

When the base resin layer of the wiring material of the present invention is a crosslinked product of the base resin, it may contain inorganic fillers, additives and the like. A cross-linking agent or cross-linking aid can be used. Further, when the base resin layer of the wiring material of the present invention is a silanol condensation cured product, it may contain inorganic fillers, additives and the like. Coupling agents, silanol condensation catalysts, carrier resins, inorganic fillers, additives and the like are preferably used.

<Organic Peroxide>
The organic peroxide generates radicals by at least thermal decomposition, and serves as a catalyst for the grafting reaction of the silane coupling agent to the ethylene-based component-containing resin by the radical reaction (grafting reaction site of the silane coupling agent and the base resin (also called (radical) addition reaction)).
As the organic peroxide, those having the above functions and used in radical polymerization or conventional silane cross-linking methods can be used without particular limitation. For example, benzoyl peroxide, dicumyl peroxide (DCP), 2,5-dimethyl-2,5-di-(tert-butylperoxy)hexane or 2,5-dimethyl-2,5-di-(tert- Butylperoxy)hexyne-3 is preferred.
The decomposition temperature of the organic peroxide is preferably 80 to 195°C, particularly preferably 125 to 180°C. In the present invention, the decomposition temperature of an organic peroxide refers to the temperature at which an organic peroxide of a single composition, when heated, causes itself to decompose into two or more compounds within a certain temperature or temperature range. means. Specifically, it refers to the temperature at which heat absorption or heat generation starts when heated from room temperature at a heating rate of 5° C./min in a nitrogen gas atmosphere by thermal analysis such as DSC method.
One type of organic peroxide may be used, or two or more types may be used.

<Silane coupling agent>
As the silane coupling agent, in the presence of radicals generated by decomposition of the organic peroxide, a site (group or atom) capable of grafting reaction to the site capable of grafting reaction of the ethylene-based component-containing resin, and a silanol condensation There is no particular limitation as long as it has a hydrolyzable silyl group. Examples of such a silane coupling agent include silane coupling agents used in conventional silane cross-linking methods.
Examples of such a silane coupling agent include silane coupling agents having an ethylenically unsaturated group as a graftable site. Specifically, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltributoxysilane, vinylsilanes such as silane, vinyldimethoxyethoxysilane, vinyldimethoxybutoxysilane, vinyldiethoxybutoxysilane, allyltrimethoxysilane, allyltriethoxysilane, vinyltriacetoxysilane; and (meth)acryloxysilane. Among them, vinyltrimethoxysilane or vinyltriethoxysilane is particularly preferred.
One type of silane coupling agent may be used, or two or more types may be used.
The silane coupling agent may be used as it is or diluted with a solvent.

<Silanol condensation catalyst>
The silanol condensation catalyst causes (promotes) the silanol condensation reaction of the silane coupling agent grafted onto the ethylene-based component-containing resin in the presence of water. Based on the function of this silanol condensation catalyst, the ethylene-based component-containing resin is crosslinked via the silane coupling agent. As a result, a silane-crosslinked resin molded article having excellent heat resistance can be obtained.
Such silanol condensation catalysts are not particularly limited, and examples thereof include organotin compounds, metallic soaps, platinum compounds and the like. Examples of organic tin compounds include dibutyltin dilaurate, dioctyltin dilaurate, dibutyltin dioctiate, and dibutyltin diacetate.
One type of silanol condensation catalyst may be used, or two or more types may be used.

<Carrier resin>
In forming the cured silanol condensation product, the silanol condensation catalyst may be used as it is, or may be used as a mixture with a resin (condensation catalyst masterbatch). The resin to be melt-kneaded (supported) with the silanol condensation catalyst (referred to as a carrier resin) is not particularly limited, and each resin described in the base resin can be used. At least one of ethylene rubber and styrene elastomer is preferred in terms of improvement), and polyethylene resin is preferred when used in combination with an inorganic filler.
A part of the base resin can be used as the carrier resin (for example, the base resin can be divided and used in steps (a) and (b-2) or (b-3) described later). In this case, the carrier resin can be used in an amount of preferably 1 to 60 parts by mass, more preferably 2 to 50 parts by mass, and even more preferably 2 to 40 parts by mass based on 100 parts by mass of the base resin.
One type of carrier resin may be used, or two or more types may be used.

<Additive>
Various additives can be used in the present invention. Examples of additives include various additives generally used in wiring materials and the like. Examples of such additives include antioxidants, cross-linking aids, lubricants, metal deactivators, and flame retardants (auxiliaries).
The antioxidant is not particularly limited, and examples thereof include benzimidazole-based antioxidants, amine-based antioxidants, phenol-based antioxidants, sulfur-based antioxidants, hydrazine-based antioxidants, and the like.

<Silane crosslinkable composition>
When the innermost coating layer of the wiring material of the present invention is formed of a silanol condensation cured product layer, a silane crosslinkable composition is used.
The silane crosslinkable composition contains at least one of ethylene rubber and styrene elastomer, at least one silane graft resin of ethylene-based component-containing resins grafted with a silane coupling agent, and a silanol condensation catalyst. , preferably an inorganic filler or the like. This silane crosslinkable composition comprises a base resin containing at least one of an ethylene rubber and a styrene elastomer and an ethylene-based component-containing resin, a silane coupling agent grafted to the ethylene-based component-containing resin, and a silanol condensation catalyst. And it can also be said that it preferably contains an inorganic filler or the like.
This composition may contain components other than the ethylene rubber and the styrene-based elastomer explained in the above base resin.

In the presence of radicals generated from an organic peroxide, the silane-grafted resin undergoes a grafting reaction between the grafting reaction sites of the silane coupling agent and the grafting reaction sites of the ethylene-based component-containing resin to form ethylene. It is a resin in which a silane coupling agent is bonded to a resin containing a system component in the form of a graft chain by a covalent bond or the like.
A commercial item may be used for Silang graft resin, and a synthetic product may be used. The silane graft resin can be synthesized by grafting an ethylene-based component-containing resin and a silane coupling agent in the presence of an organic peroxide. The grafting reaction can employ ordinary methods and conditions.

The content of each component in the silane crosslinkable composition is not particularly limited, and is appropriately set according to the application. The content of each component is set with respect to 100 parts by mass of the base resin. 100 parts by mass of the base resin means the total amount of the ethylene rubber, the styrene elastomer, the ethylene-based component-containing resin (before the silane coupling agent is grafted and bonded), other resins, and the organic mineral oil.

In the silane crosslinkable composition, the content of each component constituting the base resin in the base resin is as described above.
The content of the silane coupling agent in the silane crosslinkable composition is preferably 1 to 15 parts by mass, preferably 3 to 12 parts by mass, more preferably 4 to 12 parts by mass, relative to 100 parts by mass of the base resin. . When the silane coupling agent is grafted to the ethylene-based component-containing resin, the content of the silane coupling agent is the content of the silane coupling agent before the grafting reaction.
The content of the silanol condensation catalyst in the silane crosslinkable composition is preferably 0.01 to 0.6 parts by mass, more preferably 0.001 to 0.4 parts by mass, relative to 100 parts by mass of the base resin. be.
The silane crosslinkable composition preferably contains an inorganic filler. In this case, the content of the inorganic filler is preferably 10 to 400 parts by mass, more preferably 30 to 280 parts by mass, with respect to 100 parts by mass of the base resin. The amount of the inorganic filler to be blended is preferably less than 100 parts by mass from the viewpoint of peelability (remaining cut scum).

When several kinds of masterbatches (hereinafter sometimes referred to as MBs) are used in the preparation of the silane-crosslinkable composition, the blending amount of the components used in the preparation of each MB is the above content for the entire silane-crosslinkable composition. It is not particularly limited as long as it is a blending amount that satisfies the requirements, and is determined as appropriate. For example, when an ethylene-based component-containing resin is blended in both the silane MB and the condensation catalyst MB described later, the total amount of the ethylene-based component-containing resin used in both MBs is the total amount in the base resin used in the silane crosslinkable composition. The blending amount of each MB can be appropriately set so as to satisfy the above content of

<Method for manufacturing wiring material>
The wiring material of the present invention can be produced by kneading (melting and mixing) a base resin or a resin composition containing a base resin, and then arranging the kneaded mixture on the outer circumference of an aluminum conductor. As for the method of arranging the base resin or resin composition on the outer periphery of the aluminum conductor, any ordinary method can be applied without particular limitation. Examples thereof include a method of molding a base resin or resin composition around the outer circumference of an aluminum conductor, and a method of applying or baking a varnish of a base resin or resin composition to the outer circumference of an aluminum conductor. In the present invention, a method of molding is preferred, and a method of manufacturing a wiring member by extruding a base resin or a resin composition will be described below.

The melt-kneading method for the base resin or resin composition is not particularly limited as long as it is a method commonly used for rubbers, plastics and the like. The kneading device is appropriately selected according to the amount of the inorganic filler used, for example, when the inorganic filler is used. Specifically, single-screw extruders, twin-screw extruders, rolls, Banbury mixers, various kneaders, and the like can be used. Among them, closed mixers such as Banbury mixers and various kneaders are preferable from the standpoint of resin dispersibility. The kneading conditions are usually set at a temperature higher than the temperature at which the base resin or resin composition melts, and are appropriately set according to the resin to be used. In addition, prior to melt-kneading, mixing, for example, dry blending can be carried out without the base resin being melted, if necessary. The mixing temperature is preferably 10 to 60° C., more preferably room temperature (25° C.), and can be set for several minutes to several hours.
A method of mixing the base resin is not particularly limited. For example, each component, for example, resin components such as ethylene rubber, styrene-based elastomer, ethylene-based component-containing resin, organic mineral oil, etc., may be separately mixed. Also, the method of mixing the resin composition is not particularly limited, and the base resin may be prepared in advance and then mixed with other components, or each component constituting the base resin may be separately mixed. Alternatively, a masterbatch may be prepared using a part of the components constituting the base resin or the resin composition, dry-blended before extrusion, and mixed in the extruder.

Next, the obtained base resin or resin composition is molded (coated molding) on the outer circumference of the aluminum conductor.
The molding method is not particularly limited as long as it is a method capable of molding the base resin or resin composition into the shape of the innermost coating layer, and includes extrusion molding using an extruder, extrusion molding using an injection molding machine, and others. A molding method using a molding machine of No. 1 is mentioned, and an extrusion molding method in which the aluminum conductor is extruded simultaneously with the aluminum conductor is preferred. The molding temperature is set to the above temperature at which the base resin or resin composition melts, depending on various conditions such as the type of base resin or resin composition and the extrusion speed (take-up speed).

The kneading step and the molding step can be performed simultaneously or continuously using an extruder or the like. For example, a series of steps can be employed in which each component is introduced into an extruder (coating device), melt-kneaded (preparation of a base resin or resin composition), and then coated on the outer periphery of an aluminum conductor.

As described above, the layer of the base resin molded into the shape of the innermost coating layer can be coated on the outer peripheral surface of the aluminum conductor.
In the present invention, the surface of the innermost coating layer thus formed can be crosslinked by irradiation with an electron beam. When chemically cross-linking the innermost coating layer, the base resin or resin composition containing a cross-linking agent, a cross-linking catalyst, etc. is subjected to a cross-linking treatment by an ordinary method and conditions during or after extrusion coating, as will be described later. .
Thus, the wiring material of the present invention having a single coating layer (innermost coating layer) can be manufactured.

When the wiring material of the present invention has multiple coating layers, the wiring material can be manufactured by sequentially forming the required number of constituent layers (intermediate insulating coating layer and outermost coating layer) on the outer peripheral surface of the innermost coating layer.
Materials for forming the constituent layers are not particularly limited as long as they are commonly used for wiring materials, and organic resins are preferred. Examples of organic resins include various thermoplastic resins and thermosetting resins. For example, in addition to the base resins described above, polyvinyl chloride, polyamide, polyphenylene sulfide (PPS), polyetherketone (PEK), polyaryl Ether ketone (PAEK), tetrafluoroethylene/ethylene copolymer (ETFE), polyether ether ketone (including PEEK and modified PEEK), polyether ketone ketone (PEKK), polyethylene terephthalate (PET), polyamideimide (PAI) ), polyimide (PI), polyester (PEst), polyurethane, polyester elastomer, polyolefin elastomer, polyamide elastomer, fluororesin, fluororubber, acrylic rubber, and the like. An organic resin may be used individually by 1 type, or 2 or more types may be used for it. The organic resin may contain various commonly used additives.
Among the constituent layers, the outermost coating layer is preferably made of polyvinyl chloride. Polyvinyl chloride forming the outermost coating layer is more preferably soft polyvinyl chloride. For example, 35 to 70 parts by weight of a commonly used plasticizer and 20 to 70 parts by weight of an inorganic filler are added to 100 parts by weight of polyvinyl chloride. and a PVC composition containing
The method of forming the constituent layers is the same as the method of arranging the base resin or resin composition around the outer periphery of the aluminum conductor.

(Method for Producing Wiring Material Having Innermost Coating Layer Consisting of Cured Silanol Condensation Product of Silane Crosslinkable Composition)
When the innermost coating layer is a layer composed of a cured silanol condensation product of a silane crosslinkable composition, a preferred manufacturing method is to first add the above silane crosslinkable composition to an aluminum conductor instead of the base resin or resin composition. placed on the perimeter of Thereafter, the silane crosslinkable composition is crosslinked by contact with water. The covering molding method is the same as in the case of using the base resin or resin composition.

The silane crosslinkable composition is a crosslinkable composition containing at least one of an ethylene rubber and a styrene elastomer and a silane graft resin, comprising ethylene rubber, a styrene elastomer, a silane graft resin, a silanol condensation catalyst, preferably an inorganic It can be prepared by melting and mixing a filler or the like. Ethylene rubber and styrene-based elastomers generally tend to selectively (preferentially) undergo a silane grafting reaction with respect to an ethylene-based component-containing resin. Therefore, mixing the ethylene rubber and the styrene-based elastomer after preparation of the silane graft resin is preferable as means for avoiding cross-linking of the ethylene rubber and the styrene-based elastomer.
In this case, a rubber masterbatch containing at least one of ethylene rubber and a styrene elastomer (referred to as ethylene rubber, etc. in the manufacturing method) as a masterbatch, a silane MB containing a silane graft resin, and a condensation containing a silanol condensation catalyst. A method of kneading (melting and mixing) the catalyst MB is preferred. In this method, a composite MB containing ethylene rubber or the like and a silanol condensation catalyst is preferably used as the rubber MB and the condensation catalyst MB in terms of productivity.
The inorganic filler may be contained in one or more of the rubber MB, the silane MB, the condensation catalyst MB, and the composite MB. preferably.

In preparing the silane crosslinkable composition, the method and conditions for melt-mixing each component can appropriately adopt the method for kneading the above-described base resin or resin composition.

The silane-crosslinkable composition may be prepared using a commercially available or separately synthesized silane-grafted resin, or may be prepared through synthesis of the silane-crosslinkable resin.

-Method of preparing a silane-crosslinkable composition via synthesis of a silane-crosslinkable resin-
Methods for preparing a silane crosslinkable composition through synthesis of a silane crosslinkable resin include, for example, a step of preparing a silane MB (step of synthesizing a silane crosslinkable resin), a step of preparing a rubber MB, and, if necessary, a step of preparing a condensation catalyst MB. , a method having a melt-kneading step of a silane MB, a rubber MB and a silanol condensation catalyst or a condensation catalyst MB.

(a) Preparation step of silane MB In the preparation step of silane MB, for example, a base resin containing at least an ethylene-based component-containing resin, an organic peroxide, an inorganic filler if necessary, and a silane coupling agent are combined with an organic Melt-kneading at a temperature equal to or higher than the decomposition temperature of the peroxide to cause a grafting reaction between the base resin and the silane coupling agent by radicals generated from the organic peroxide, thereby producing a reaction composition containing a silane crosslinkable resin ( a step of preparing silane MB as a melt-kneaded product).
As described above, this step is preferably melt-kneaded in the absence of ethylene rubber or the like. In the present invention, melt-kneading in the absence of ethylene rubber or the like means melt-kneading without substantially blending ethylene rubber or the like. It may be present as long as the chemical reaction can be suppressed within a range that does not impair the effects of the present invention.

It is preferable to use an inorganic filler in the step of preparing the silane MB from the viewpoint that the resulting cured product layer and, in turn, the wiring material of the present invention exhibit high heat resistance.
In this method, the blending amount of each component is set to a blending amount that satisfies the above content of the silane-crosslinkable composition as a whole. For example, the blending amounts of the inorganic filler, silane coupling agent and silanol condensation catalyst are as described above. The amount of the organic peroxide compounded is preferably 0.01 to 0.6 parts by mass, more preferably 0.05 to 0.3 parts by mass, with respect to 100 parts by mass of the base resin used for preparing the silane crosslinkable composition. Preferably, 0.07 to 0.25 parts by mass is more preferable.

In the step of preparing the silane MB, the mixing order of each component is not particularly limited, and may be mixed in any order. Although each component can be melt-kneaded at once, when using an inorganic filler, it is preferable to melt-knead each component by the following steps (a-1) and (a-2).
Step (a-1): Step of mixing at least an inorganic filler and a silane coupling agent to prepare a mixture Step (a-2): The mixture obtained in Step (a-1); A step of melt kneading the base resin and the base resin in the presence of the organic peroxide at a temperature equal to or higher than the decomposition temperature of the organic peroxide

In step (a-1), the method for mixing the inorganic filler and the silane coupling agent is not particularly limited, and dry mixing in which the inorganic filler is mixed with the silane coupling agent with or without heating is preferred. Through this process, an inorganic filler with a silane coupling agent bonded or adsorbed with a strong bond (via a hydrolyzable silyl group capable of silanol condensation) on the surface (site that can be chemically bonded) and a silane coupling agent with a weak bond on the surface. An inorganic filler to which a ring agent is bound or adsorbed can be prepared. Weak bonds include interactions due to hydrogen bonds, interactions between ions, partial charges or dipoles, actions due to adsorption, etc. Strong bonds include chemical bonds with sites that can be chemically bonded on the surface of the inorganic filler. etc. This makes it possible to reduce the volatilization of the silane coupling agent in step (a-2) and the like, and to prepare or manufacture a highly heat-resistant cured product and wiring material. The mixing conditions in step (a-1) are not particularly limited, and examples thereof include the dry blending conditions described above.

Next, the mixture obtained in step (a-1), the base resin, and the remaining components not mixed in step (a-1) are combined in the presence of the organic peroxide to decompose the organic peroxide. Melt and knead at a temperature above the temperature. As a result, radicals generated from the organic peroxide cause a grafting (bonding) reaction between the grafting reaction site of the silane coupling agent and the graftable site of the base resin.
In steps (a) and (a-2), the temperature at which the above components are melt-kneaded is the decomposition temperature of the organic peroxide or higher, preferably the decomposition temperature of the organic peroxide + (25 to 110)°C. , for example at a temperature of 150-230°C. Other melt-kneading conditions, such as mixing time, can be appropriately set. The kneading method is the same as the above kneading method and conditions for the base resin or resin composition.

The organic peroxide may be present when performing step (a-2), and may be mixed in step (a-1) or mixed in step (a-2). When the organic peroxide is mixed in step (a-1), the mixing temperature is kept below the decomposition temperature of the organic peroxide.
In the step (a-2), the silane coupling agent is grafted at its grafting reaction site to the graftable site of the ethylene-based component-containing resin. At this time, the silane coupling agent bound or adsorbed to the inorganic filler by a weak bond desorbs from the inorganic filler and undergoes a grafting reaction. On the other hand, the silane coupling agent bound or adsorbed to the inorganic filler with a strong bond undergoes a grafting reaction while maintaining the bond with the inorganic filler.

Thus, a silane graft resin is synthesized by grafting the base resin and the silane coupling agent, and a silane MB) containing this silane graft resin is prepared as a reaction composition.

(b-1) Preparation of Rubber MB In the method of preparing a silane-crosslinkable composition through synthesis of a silane-crosslinkable resin, a rubber MB is prepared. The rubber MB may contain other components as long as it contains at least ethylene rubber or the like. Preparation of the rubber MB is not particularly limited as long as it is a method of kneading ethylene rubber or the like while it is molten.

(b-2) Preparation step of condensation catalyst MB In the method of preparing the silane crosslinkable composition through the synthesis of the silane crosslinkable resin, if necessary, the silanol condensation catalyst and the carrier resin are melt-mixed to prepare the condensation catalyst MB. Prepare. The melt-kneading of the carrier resin and the silanol condensation catalyst is not particularly limited as long as it is a method carried out while the carrier resin is molten, and the melt-mixing method and conditions in the method of kneading the base resin or the resin composition can be appropriately employed.

(b-3) Composite MB Preparation Step In the method of preparing a silane-crosslinkable composition through the synthesis of a silane-crosslinkable resin, instead of the rubber MB and the condensation catalyst MB, the condensation catalyst MB is used in terms of productivity. It is more preferable to prepare and use a composite MB using ethylene rubber or the like as a carrier resin. The preparation of the composite MB is not particularly limited as long as it is a method of kneading ethylene rubber, carrier resin, or the like under melting.

(b-4) Melt-kneading step In the method of preparing the silane-crosslinkable composition through the synthesis of the silane-crosslinkable resin, the silane MB, the rubber MB, and the silanol condensation catalyst or condensation catalyst MB are then melt-kneaded. . For the melt-kneading, the melt-mixing method and conditions in the method for kneading the base resin or the resin composition can be appropriately employed.

In the wiring material manufacturing method, other resins and additives that can be used in addition to the above components may be kneaded or mixed in any step, and the order of mixing in each step is not particularly limited. The amount of the additive to be added is not particularly limited, and can be appropriately set within a range that does not impair the intended effect. The blending amount of the antioxidant can be appropriately set, but is preferably 0.1 to 15.0 parts by mass, more preferably 0.1 to 10 parts by mass, relative to 100 parts by mass of the resin composition.

Thus, the silane crosslinkable composition can be prepared through synthesis of the silane crosslinkable resin.

(c) Placement step of silane crosslinkable composition In the method of producing a wiring material having an innermost coating layer comprising a silanol condensation cured product of a silane crosslinkable composition, the silane crosslinkable composition is placed on the outer circumference of the aluminum conductor. do. The arrangement method of the silane crosslinkable composition is the same as in the case of using the base resin or resin composition.

(d) Crosslinking step of silane crosslinkable composition Next, the silane crosslinkable composition coated and molded around the aluminum conductor is brought into contact with water to crosslink. As a result, the hydrolyzable silyl group of the silane coupling agent is hydrolyzed by water to form a silanol (OH group bonded to a silicon atom), and the silanol condensation catalyst present in the silane crosslinkable composition causes the hydroxyl groups of the silanol to (Dehydration) condensation occurs and a cross-linking reaction occurs (silanol condensation cure of the silane-crosslinkable composition is formed). The method of cross-linking may be a method of leaving the coated silane cross-linkable composition at room temperature, a method of leaving the coated silane cross-linkable composition under humidification or heating, or a method of leaving the coated silane cross-linking composition. A method of immersing the sexual composition in warm water may also be used.

In this way, a wiring material is produced in which the innermost coating layer comprising the silanol condensation cured product of the silane crosslinkable composition is provided on the outer periphery of the aluminum conductor.
The silanol condensation cured product of the silane crosslinkable composition is a silane graft resin obtained by grafting a silane coupling agent to an ethylene component-containing resin, at least one of ethylene rubber and styrene elastomer, and in a preferred embodiment, an inorganic filler. For the silane crosslinkable composition containing and, the hydrolyzable group of the silane coupling agent bonded to the silane graft resin is hydrolyzed and then crosslinked by silanol condensation. This silane graft resin contains a crosslinked resin condensed via a silanol bond (siloxane bond). In a preferred embodiment in which the silane crosslinkable composition contains an inorganic filler, the inorganic filler may be bonded to the silane coupling agent of the silane graft resin. In the silane crosslinkable composition and silanol condensation cured product, the ethylene rubber and styrene elastomer are not crosslinked with other resins.
Therefore, this cured product layer contains a crosslinked cured product of a Silang graft resin, at least one of ethylene rubber and styrene elastomer, and in a preferred embodiment, an inorganic filler. The crosslinked cured product of the silane graft resin has a base resin component (ethylene component-containing resin component, ethylene rubber component, styrene elastomer component), a silane coupling agent component, and in a preferred embodiment, an inorganic filler component. is doing. The content of each component in the cured product layer varies depending on the reaction conditions, the reaction rate, etc., but is preferably within the above range. More specifically, in this cured product layer, the reaction site of the silane coupling agent grafted to the silane graft resin is hydrolyzed and a silanol condensation reaction occurs with each other, so that the silane graft resins are crosslinked via the silane coupling agent. The silane crosslinked resin and at least one of ethylene rubber and styrene elastomer, preferably the silane graft resin is bound or adsorbed to the inorganic filler by the silane coupling agent, and bound through the inorganic filler and the silane coupling agent ( crosslinked) and crosslinked resins.

Specifically, the method for producing the wiring material of the present invention having the innermost coating layer made of a cured silanol condensation product includes the following preparation step (A), preparation step (B), arrangement step (C) and It has a cross-linking step (D).
Preparation step (A): An organic peroxide, preferably an inorganic filler, and a silane coupling agent are added to a base resin containing at least an ethylene-based component-containing resin at a temperature equal to or higher than the decomposition temperature of the organic peroxide. In, preferably in the absence of ethylene rubber or the like and a silanol condensation catalyst, by melt-kneading and grafting the silane coupling agent to the base resin by radicals generated from the organic peroxide, the silane graft resin is obtained. Preparation step (B): A step of melt-kneading the silane MB, ethylene rubber or the like, and a silanol condensation catalyst Arrangement step (C): The silane crosslinkable composition obtained in the preparation step (B) on the outer peripheral surface of the aluminum conductor Crosslinking step (D): The step of contacting the silane crosslinkable composition placed on the outer peripheral surface of the aluminum conductor with water

In the above method, the method of melt-kneading the ethylene rubber or the like and the silanol condensation catalyst in the preparation step (B) is not particularly limited. For example, it may be a step of melt-kneading a silane MB, a rubber MB containing at least ethylene rubber or the like, and a condensation catalyst MB containing a silanol condensation catalyst. It may be a step of melt-kneading the contained composite MB.
The steps in the preferred production method having steps (A) to (D) are respectively the above steps (a), steps (b-1) to (b-4), step (c), and step Corresponding to (d), the methods and conditions described in each of these steps can be applied as appropriate.
In addition, for each step in the preferred production method, further, the reaction in the silane crosslinking method and the form of the condensed cured product obtained, for example, the description of JP-A-2017-145370 can be applied as appropriate, and the description in this publication can be applied. The contents are incorporated as part of this description as is.

EXAMPLES The present invention will be described in more detail below based on examples, but the present invention is not limited to these.
In Tables 1 to 4, the numerical values relating to the compounding amounts in each example represent parts by mass unless otherwise specified. A blank column for each component means that the amount of the corresponding component is 0 parts by mass.

Details of each component (compound) used in Examples and Comparative Examples are shown below.
<Base resin>
- Ethylene rubber -
Mitsui EPT0045H: trade name, EPM, Mitsui Chemicals Co., Ltd. Nodel 3720P: trade name, EPDM (ethylene-propylene-ethylidene norbornene rubber), manufactured by Dow Chemical Company - styrene elastomer -
Septon 4077: trade name, SEEPS, manufactured by Kuraray Tuftec (registered trademark) N504: Hydrogenated SEBS (styrene/ethylene-butylene ratio = 32/68, manufactured by Asahi Kasei Corporation)
Septon 4033: Trade name, SEEPS, manufactured by Kuraray Co., Ltd. -Resin containing ethylene-based component-
Evolue SP1540: trade name, LLDPE, manufactured by Prime Polymer)
Evolue SP0540: trade name, LLDPE, manufactured by Prime Polymer)
NUC7540: trade name, LLDPE, PB222A manufactured by Nihon Unicar Co., Ltd.: trade name, polypropylene (ethylene-propylene random copolymer), manufactured by SunAllomer NUC6520: trade name, ethylene-ethyl acrylate copolymer resin, manufactured by Nihon Unicar Co., Ltd. EV360: Evaflex EV360 (trade name), ethylene-vinyl acetate copolymer, Adtex L6100M manufactured by Mitsui-DuPont Polychemicals: trade name, maleic acid-modified polyethylene, manufactured by Japan Polyethylene - organic mineral oil -
Diana Process PW-90: Product name, paraffin oil, manufactured by Idemitsu Kosan Co., Ltd. <Silane graft resin>
Linklon XF730T: trade name, Silang-grafted LLDPE (grafted with vinyl methoxysilane as a silane coupling agent), manufactured by Mitsubishi Chemical Corporation <Inorganic filler>
Aerosil 200: trade name, hydrophilic fumed silica, Kisuma 5L manufactured by Nippon Aerosil Co., Ltd.: trade name, silane coupling agent surface-treated magnesium hydroxide, Softon 1200 manufactured by Kyowa Chemical Industry Co., Ltd.: trade name, calcium carbonate, Bihoku Funka Kogyo Co., Ltd. Glowmax LL manufactured by Glowmax LL: trade name, Karion Clay (calcined Karion), Crystalite 5X manufactured by Takehara Chemical Industry Co., Ltd.: Trade name, crystalline silica, manufactured by Tatsumori <Silane coupling agent>
KBM-1003: trade name, vinyltrimethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd. <organic peroxide>
Permil D: trade name, dicumyl peroxide, decomposition temperature 151 ° C., manufactured by NOF <Antioxidant>
Irganox 1010: trade name, pentaerythritol tetrakis [3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate], manufactured by BASF Irganox 1076: trade name, octadecyl-3-(3,5 -Di-tert-butyl-4-hydroxyphenyl) propionate, manufactured by BASF <Silanol condensation catalyst>
ADEKA STAB OT-1: trade name, dioctyltin dilaurate, manufactured by ADEKA <PVC mixture>
SHV9877P: Product name, PVC compound: Hardness 80A, manufactured by Riken Technos

<Preparation of masterbatch>
- Preparation of composite MB (resin composition) A -
Base resin (used as carrier resin in Examples 5 to 12), inorganic filler, antioxidant and silanol condensation catalyst were added to the Banbury mixer at the blending amounts shown in the "Composite MB [A]" column of Tables 1 to 4. After charging and melting and kneading at 190° C., the material was discharged at a discharge temperature of 200° C. and passed through a feeder ruder to obtain composite MB[A] pellets.
In Comparative Example 2, pellets obtained by melting and kneading the base resin antioxidant at 170°C and then discharging at a material discharge temperature of 180°C, and the organic peroxide in the blending amount shown in Table 4 were mixed. , using a roll mixture set at a roll temperature of 90° C., to obtain composite MB[A] pellets.
- Preparation of silane MB [C] -
The organic peroxide and the silane coupling agent are mixed at 25 ° C. in the amounts shown in the "Silane MB [C]" column of Tables 1 and 2, then the base resin and antioxidant are added and blended. (30° C.) for 5 minutes. The resulting mixture was added to a 65 mmφ single-screw kneader (ratio of screw effective length L to diameter D: L/D = 30) set at a cylinder temperature of 195°C and a head temperature of 200°C to obtain a strand. The strand was cooled with water, and after the water was blown off, the strand was passed through a round pelletizer to obtain pellets of silane MB[C].
The silane grafting reaction was caused by melt-kneading in the single-screw kneader. This silane MB[C] contains a silane crosslinkable resin obtained by grafting a silane coupling agent to an ethylene component-containing resin.
- Preparation of silane MB [D] -
A mixture obtained by mixing an organic peroxide and a silane coupling agent at 25° C. in the amounts shown in the “Silane MB [D]” column of Table 2 is added to the inorganic filler and stirred for 10 minutes with a Henschel mixer (at 30° C. ) to obtain an inorganic filler mixture. Next, the obtained inorganic filler mixture was added to the Banbury mixer together with the base resin and the antioxidant component at the blending amounts shown in the same column, kneaded at 190°C for 10 minutes, and discharged at 200°C. After discharge, silane MB[D] pellets were obtained by hot cutting through a feeder ruder.
The silane grafting reaction was caused by melt-kneading in the Banbury mixer. This silane MB[D] contains a silane crosslinkable resin obtained by grafting a silane coupling agent to an ethylene component-containing resin.

<Preparation of dry blend>
- Preparation of dry blend B -
The composite MB [A] pellets and the silane MB [B] pellets are dry blended at the blending amounts shown in the "Composite MB [A]" column and the "Silane MB [B]" column in Table 1. Item B was prepared.
- Preparation of dry blend C -
Composite MB[A] pellets and silane MB[C] pellets were dry-blended at the compounding amounts shown in the "Composite MB[A]" and "Silane MB[C]" columns in Tables 2 and 3. , a dry blend B was prepared.
- Preparation of dry blend D -
Composite MB [A] pellets and silane MB [D] pellets are dry blended at the blending amounts shown in the "Composite MB [A]" and "Silane MB [D]" columns in Table 3. Item D was prepared.

<Manufacture of aluminum conductor wire>
- Reference Examples 1, 4, 13 to 18, Comparative Examples 1, 5 and 6 -
An aluminum conductor provided with a layer composed of a non-crosslinked base resin composition as the innermost coating layer on the outer peripheral surface of the aluminum conductor using the composite MB [A] alone or using the dry blend B ( Reference Example 4) Made a wire.
Composite MB[A] pellets or dry blend B were introduced into an extruder (L/D=24, compression section screw temperature 190° C., head temperature 200° C.) equipped with a 40 mm diameter screw. While melting and kneading the composite MB [A] or the dry blend B in this extruder, the outer peripheral surface of the 1/0.8 mm aluminum conductor is directly extruded and coated (arranged) with a thickness of 1 mm. A coated conductor with a small diameter of 2.8 mm was obtained.
Separately, composite MB[A] pellets or dry blend B were introduced into an extruder equipped with a 90 mm diameter screw (L/D = 28, compression section screw temperature 190°C, head temperature 200°C). did. While melt kneading the composite MB [A] or the dry blend B in this extruder, a thickness of 1 on the outer peripheral surface of a 38SQ (19/1.6) (conductor diameter 7.3 mm) aluminum stranded wire as a conductor. Direct extrusion coating (placement) at 0.2 mm yielded a thick coated conductor with an outer diameter of 9.7 mm.
In this way, two types of aluminum conductor wires (small-diameter insulated wire and large-diameter insulated wire) having a single-layer coating layer (innermost coating layer) were produced.
In addition, the PVC mixture was introduced into an extruder (L/D = 28, compression part screw temperature 180 ° C., head temperature 18 ° C.) equipped with a screw with a diameter of 90 mm, and the insulated wire with an outer diameter of 9.7 mm (thick A PVC resin mixture was coated on the outer side of the diameter-coated conductor) to form a sheath layer with a thickness of 1.5 mm. In this way, a cable with a two-layer coating having an outer diameter of 12.7 mm was produced.

- Examples 2 and 3, and Comparative Examples 3 and 4 -
Using the above dry blend B, an aluminum conductor electric wire having a silanol condensate cured product layer as the innermost coating layer on the outer peripheral surface of the aluminum conductor was produced.
In the production of the aluminum conductor wire of Reference Example 1, the dry blend B was used in place of the composite MB [A] pellets, and the two types of coated conductors obtained were heated at a temperature of 60°C and a relative humidity of 95%. Two types of aluminum conductor wires having a single coating layer were produced in the same manner as the aluminum conductor wires of Reference Example 1, except that the aluminum conductor wires were left in an atmosphere of 1 for 24 hours and brought into contact with water. In this example, by bringing the coated conductor into contact with water, the trimethoxy group of the silane coupling agent was subjected to hydrolysis reaction and then silanol condensation reaction to cause silane cross-linking.
In addition, a cable with an outer diameter of 12.7 mm was manufactured in the same manner as the cable of Reference Example 1.

- Examples 5 to 9 -
Using the above dry blend C, an aluminum conductor electric wire having a silanol condensate cured product layer as the innermost coating layer on the outer peripheral surface of the aluminum conductor was produced.
In the production of the aluminum conductor wire of Reference Example 1, the dry blend C was used in place of the composite MB [A] pellets, and the two types of coated conductors obtained were heated at a temperature of 60°C and a relative humidity of 95%. Two types of aluminum conductor wires having a single coating layer were produced in the same manner as the aluminum conductor wires of Reference Example 1, except that the aluminum conductor wires were left in an atmosphere of 1 for 24 hours and brought into contact with water. In this example, the coated conductor (the melt-kneaded product of the dry blend C extruded on the outer peripheral surface of the aluminum conductor) was brought into contact with water to hydrolyze the trimethoxy group of the silane coupling agent, followed by a silanol condensation reaction. silane cross-linked.
In addition, a cable with an outer diameter of 12.7 mm was manufactured in the same manner as the cable of Reference Example 1.

- Examples 10 to 12 -
Using the above dry blend D, an aluminum conductor electric wire having a silanol condensate cured product layer as the innermost coating layer on the outer peripheral surface of the aluminum conductor was produced.
In the production of the aluminum conductor wire of Reference Example 1, the dry blend D was used in place of the composite MB [A] pellets, and the two types of coated conductors obtained were heated at a temperature of 60°C and a relative humidity of 95%. Two types of aluminum conductor wires having a single coating layer were produced in the same manner as the aluminum conductor wires of Reference Example 1, except that the aluminum conductor wires were left in an atmosphere of 1 for 24 hours and brought into contact with water. In this example, the coated conductor (the melt-kneaded product of the dry blend D extruded onto the outer peripheral surface of the aluminum conductor) was brought into contact with water to hydrolyze the trimethoxy group of the silane coupling agent, followed by a silanol condensation reaction. silane cross-linked.
In addition, a cable with an outer diameter of 12.7 mm was manufactured in the same manner as the cable of Reference Example 1.

- Comparative Example 2 -
Using the composite MB[A] pellets alone, an aluminum conductor electric wire was produced in which a layer composed of a crosslinked base resin composition was provided on the outer peripheral surface of an aluminum conductor as the innermost coating layer.
Pellets of composite MB[A] were introduced into an extruder (L/D=22, compression section screw temperature 120° C., head temperature 125° C.) equipped with a 65 mm diameter screw. With this extruder, the composite MB [A] was directly extruded (arranged) with a wall thickness of 1 mm on the outer peripheral surface of a 1/0.8 mm aluminum conductor as a conductor, and then a steam bridge tube set at 200 ° C. and 4.5 atmospheres. to obtain a thin coated conductor with an outer diameter of 2.8 mm.
Separately, pellets of composite MB[A] were introduced into an extruder (L/D=24, compression section screw temperature 110° C., head temperature 120° C.) equipped with a 115 mm diameter screw. With this extruder, after directly extruding (arranging) the composite MB [A] with a thickness of 1.2 mm on the outer peripheral surface of a 38SQ (19/1.6) (conductor diameter 7.3 mm) aluminum stranded wire conductor as a conductor, A thick coated conductor with an outer diameter of 9.7 mm was obtained through a steam bridge tube set at 200° C. and 3.5 atmospheres.

The manufactured insulated wires and cables were evaluated as follows, and the results are shown in Tables 1 to 4.
<Workability test>
(Cutting property test of insulated wire)
The stripping workability of the insulated wire was evaluated by a cutting test based on the following tests.
- 1. Presence/absence of beard generation confirmation test -
A thin insulated wire using a 1/0.8 mm aluminum conductor produced in each example , reference example and comparative example (hereinafter referred to as each example and reference example) was processed with a wire stripper, and the presence or absence of whiskers It was confirmed. The whiskers refer to linear bodies (hair-like bodies) of the insulating coating layer that remain on the cut end face (extend from the cut end face) because the insulating coating layer cannot be cut in the thickness direction.
A stripper with a hole diameter of 0.8 mm was used, and the peeling length of the coating layer was 15 mm. This processing was tested four times for each small-diameter insulated wire.
The evaluation was "A" when the length of the beard generated in the cut part was 4 mm or less in all four tests, and the length of the beard generated in the cut part in all four tests exceeded 4 mm and was 8 mm. A case where the length of the whisker was below 8 mm was given as "B", and a case where the length of the whisker generated at the cut portion exceeded 8 mm even once was given as "C". In this test, evaluation ranks "A" and "B" are passed.

- 2. Remaining confirmation test of cut shavings -
The large-diameter insulated wires using the 38SQ aluminum stranded wire produced in each example and comparative example were processed with a wire stripper, and the cutting residue of the insulating coating layer remaining on the surface and inside of the aluminum stranded wire was confirmed.
A stripper with a hole diameter of 9.0 mm was used, and the stripping length of the coating layer was 15 mm. This processing was tested four times for each large-diameter insulated wire.
The evaluation was "A" when no cut residue remained in the aluminum stranded wire at the cut portion in all four tests, and when it was confirmed that cut residue remained in the aluminum stranded wire at the cut portion even once. was rated as "B", and a case in which cut shavings remained in the aluminum stranded wire at the cut portion in two or more tests was rated as "C". In this test, evaluation ranks "A" and "B" are passed.

<Flexibility test of insulated wire>
When the large-diameter insulated wire using the 38SQ aluminum stranded wire produced in each example and comparative example was bent into a U shape in 4D (D indicates the radius of the large-diameter insulated wire) (U-shaped bending The inner diameter of the part was four times the radius of the large diameter insulated wire), and the force required to bend it was measured with a Tensilon.
Tables 1-4 list the measured values of the force required to bend. In this test, when the force required for bending is 50N or less, it is "passed", and when it exceeds 50N, it is rejected.

<Cable Flexibility Test>
When a cable with an outer diameter of 12.7 mm manufactured in each example and comparative example is bent in a U shape in 4D (D indicates the radius of the cable) (the diameter of the U-shaped bent portion is the radius of the cable) 4 times), the force required to bend was measured with a Tensilon.
Tables 1-4 list the measured values of the force required to bend. In this test, when the force required for bending is 65N or less, it is "passed", and when it exceeds 65N, it is rejected. Flexibility is very good when this force is 50 N or less.

<Heating winding test>
The heat resistance of the insulated wire was evaluated by the heating winding test described below.
Specifically, a thin insulated wire using a 1/0.8 mm aluminum conductor manufactured in each example and comparative example was wound around a mandrel having the same outer diameter as the self diameter (diameter) for 6 turns to obtain a test sample. was made. This test sample was left in a constant temperature bath at 120° C. for 24 hours. After the standing, the test sample was returned to normal temperature, the thin insulated wire was unwound from the test sample, and its surface was confirmed.
The evaluation was "A" when the thin insulated wire was not melted all over, and the thin insulated wire was melted and fused with the adjacent thin insulated wire (turn parts), but the aluminum conductor A case where the insulated wire was not visible was rated as "B", and a case where the thin insulated wire was melted and the aluminum conductor was exposed was rated as "C". This test is a reference test. When the evaluation rank is "A" or "B", the heat resistance is high, showing heat resistance equal to or higher than that exhibited by a thin insulated wire manufactured in the same manner except that a copper conductor was used. It was confirmed that the insulated wires of the reference examples having the evaluation rank of "C" satisfied the normal heat resistance required for insulated wires.

The results in Tables 1 to 4 reveal the following.
The wiring materials of the comparative examples, in which the aluminum conductor and the innermost coating layer made of the base resin containing at least one of ethylene rubber and styrene elastomer are not used in combination, are all inferior in the cuttability test and the flexibility test of the insulated wire. It does not have both peelability and flexibility.
That is, Comparative Example 1 is a wiring material having an innermost coating layer made of a non-crosslinked base resin composition (containing no ethylene rubber or styrene elastomer), and is inferior in peelability (bearing) and flexibility. , does not show sufficient heat resistance. Comparative Example 2 is a wiring material having an innermost coating layer (containing no ethylene rubber or styrene-based elastomer) in which the base resins are self-crosslinked with an organic peroxide instead of silane cross-linking. Flexibility is also inferior. Comparative Examples 3 and 4 are wiring members having an innermost coating layer formed using a base resin containing neither ethylene rubber nor styrene elastomer and silane crosslinkable composition B containing no inorganic filler. Although it exhibits sufficient heat resistance, it is inferior in workability (bearing generation) and flexibility. Comparative Example 5 is a wiring material having an innermost coating layer formed using a base resin containing neither ethylene rubber nor styrene elastomer and a non-crosslinked base resin composition containing a small amount of inorganic filler, and has peelability. (The occurrence of whiskers cannot be suppressed, and cut shavings remain remarkably), the flexibility is inferior, and the heat resistance is not sufficient. Comparative Example 6 is a wiring material having an innermost coating layer formed using a base resin composition containing neither ethylene rubber nor styrene-based elastomer, and has low flexibility and processability of resin containing ethylene-based component ( whiskers) and flexibility, and heat resistance is not sufficient.

On the other hand, in the wiring members of Examples and Reference Examples , in which an aluminum conductor and an innermost coating layer made of a base resin containing at least one of ethylene rubber and styrene elastomer are combined and arranged in direct contact with each other, All of them passed the cutting property test and the flexibility test of the insulated wire, indicating that they have both excellent stripping workability and flexibility. Furthermore, Examples 2 , 3, and 5 to 12, which have an innermost coating layer obtained by silane-crosslinking an ethylene-based component-containing resin that has undergone a silane-grafted reaction, do not impair excellent peelability and flexibility. It can be seen that it also has high heat resistance. In particular, Examples 10 to 12 exhibit higher heat resistance because the silane coupling agent used for silane cross-linking is bound or adsorbed to the inorganic filler and then silane-grafted to the ethylene-based component-containing resin.

Claims (5)

A wiring material having at least one insulating coating layer on the outer periphery of an aluminum conductor,
A wiring material, wherein the innermost insulating coating layer directly provided on the outer periphery of the aluminum conductor among the insulating coating layers is a layer of a silanol condensation cured product of the following silane crosslinkable composition.
<Silane crosslinkable composition>
At least one of ethylene rubber and styrene elastomer , and ethylene-α-olefin copolymer resin grafted with silane coupling agent, polyethylene, polypropylene, and polyolefin copolymer resin having acid copolymer component. A base resin containing at least one silane graft resin and a silanol condensation catalyst ,
When the base resin contains the styrene-based elastomer, the content in the base resin is 10% by mass or more, and when the base resin contains an ethylene-vinyl acetate copolymer resin, in the base resin A silane crosslinkable composition having a content of 10% by mass or less The wiring material according to claim 1, wherein the total content of the ethylene rubber and the styrene-based elastomer in the base resin is 15% by mass or more . 3. The wiring material according to claim 1, wherein the base resin contains an organic mineral oil. The wiring material according to any one of claims 1 to 3, wherein the silane crosslinkable composition contains 10 to 400 parts by mass of an inorganic filler with respect to 100 parts by mass of the base resin. The wiring material according to any one of claims 1 to 4, wherein the insulating coating layer has two or more layers, and the outermost insulating coating layer is a polyvinyl chloride insulating coating layer.