JP2003007155A - Manufacturing method of coated electric wire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a coated electric wire which enables efficient manufacturing of a coated electric wire excellent in flame retarding property, especially effective by its shape-retaining capacity at time of burning, fine mechanical strength, flexibility, elongation and heat characteristics and farther a characteristic of easily being separated from polyvinyl chloride resins. SOLUTION: The coating layer of en electric wire comprises a polyolefin resin composition consisting of 2-50 wt.% of a master batch (A) containing a polyolefin resin and a layered silicate, 20-70 wt.% of a master batch (B) containing a polyolefin and a flame-retarding agent and 10-90 wt.% of a polyolefin resin. The coating is formed on the outer periphery of an electric wire continuously along the lengthwise direction. The layered silicate is specifically selected from montmorillonite, a swelling mica and/or talc. Additionally, the layered silicate has been converted to be organic by replacing exchangeable metal cations in a crystalline part of the silicate with a cationic surfactant.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for manufacturing a covered electric wire.

[0002]

2. Description of the Related Art Generally, an electric wire coating resin (electric wire sheath resin) is required to have flame retardancy for the purpose of preventing the spread of the flame that propagates through the electric wire coating layer (electric wire sheath layer) at the time of fire (J.
ISC-3005 "Rubber / Plastic insulated wire test method"). Therefore, as a polymer material for wire coating,
Conventionally, soft polyvinyl chloride resins have been widely used.

On the other hand, in recent years, polymeric materials used for industrial purposes have been required to be environmentally friendly materials because of the problems of waste plastic processing and environmental hormones.
It is desired to switch to environmentally friendly materials. In particular,
Due to problems such as dioxin generation during combustion and toxicity of plasticizers that are commonly added to soft polyvinyl chloride resins, conversion from polyvinyl chloride resins to, for example, polyolefin resins is being studied. . For this reason, in recent years, in the field of electric wire coating resins, in order to switch to environmentally friendly materials, electric wires using a polyolefin resin as a coating layer, so-called eco electric wires, have been developed.

However, polyolefin resins are one of the resins having the highest flammability, and it is the most difficult task to develop flame retardancy. At present, in many cases, a large amount of flame retardant is kneaded into a polyolefin resin for use.

Among the above flame retardants, the flame retardant composed of a halogen-containing compound has a high flame retarding effect, and the deterioration of the moldability and the mechanical strength of the obtained molded body are relatively small. If used, a large amount of halogen-based gas may be generated during molding or combustion, and the halogen-based gas generated may corrode equipment or have an unfavorable effect on the human body. Practical application of so-called non-halogen flame-retardant technology that does not use halogen-containing compounds is strongly desired.

As one of the halogen-free flame-retardant techniques for polyolefin resins, a method of adding a metal compound such as aluminum hydroxide, magnesium hydroxide or basic magnesium carbonate, which does not generate a toxic gas during combustion, is known. JP-A-57-165437 and JP-A-61-161
It is disclosed in Japanese Patent No. 36343 and the like.

However, in order to impart sufficient flame retardancy to the flammable polyolefin resin, it is necessary to add a large amount of a metal compound, and as a result, the mechanical strength of the obtained molded product is significantly lowered. However, there is a problem that it is difficult to put it into practical use.

[0008] Among the above metal compounds, when a metal hydroxide such as aluminum hydroxide or magnesium hydroxide is added to the polyolefin resin, a coating layer cannot be formed during combustion and brittle ash is exposed. However, since the residue falls off, there is a problem that the function as a heat insulating layer is lost at an early stage and the spread of flame due to the deformation of the material cannot be stopped.

Further, a method has been proposed in which a phosphorus-based flame retardant is added to a polyolefin-based resin to form a coating layer on the surface at the time of combustion, and the oxygen blocking effect of this coating layer is utilized to develop flame retardancy. ing.

However, in order to impart sufficient flame retardancy to the flammable polyolefin resin, it is necessary to add a large amount of phosphorus-based flame retardant, and as a result, the mechanical strength of the resulting molded article is increased. There is a problem that it is significantly reduced and it is difficult to put it to practical use.

When a phosphorus-based flame retardant is added to a polyolefin-based resin, it is possible to locally form a coating layer, but it is difficult to form a strong coating layer as a continuous layer. The mechanical strength of the coating layer is very weak, brittle ash is exposed during combustion, and the residue falls off, so that the function as a heat insulating layer is lost early and the spread of flame due to material deformation cannot be stopped. There is a problem.

Further, for example, JP-A-6-25476 discloses a resin composition in which red phosphorus or a phosphorus compound and heat-expandable graphite are added to a polyolefin resin.

The resin composition disclosed in the above publication is
Although it has sufficient flame retardancy when viewed from the oxygen index, in practice it is possible to form the coating layer only locally, and it is not possible to form a strong coating layer as a continuous layer. Mechanical strength of the typical coating layer is very weak,
Since brittle ash is exposed during combustion and the residue falls off, there is a problem that the function as a heat insulating layer is lost early and the spread of flame due to deformation of the material cannot be stopped.

Further, in recent years, a silicone-based flame retardant has attracted attention as a flame retardant that does not contain halogen or phosphorus and is highly safe and can be compounded in a wide range of polymer materials.

The above-mentioned silicone-based flame retardant migrates to the surface of the material at the time of burning to form a non-combustible coating layer, so that the flame retardancy can be exhibited by utilizing the oxygen blocking effect of the non-combustible coating layer. It is said that.

However, when a silicone-based flame retardant is added to a polyolefin-based resin, the oxygen index itself is significantly improved, but a strong non-combustible coating layer cannot be formed during actual combustion, and mechanical strength is weak. Since flammable gas leaks from the cracks in the non-combustible coating layer, there is a problem that the spread of flame cannot be stopped.

When these flame retardants are used in the wire coating material, a large amount of the flame retardant must be added in order to exhibit the predetermined flame retardancy, so that the physical properties required for the coated wire are required. Since it is difficult to secure a certain degree of flexibility and elongation, and the specific gravity is high, it is close to the specific gravity of polyvinyl chloride resin. There is a problem that it is difficult to separate it from.

On the other hand, as a method of manufacturing a covered electric wire, a pellet of a polymer material (resin) and a flame retardant are uniaxially or biaxially.
A method of coating the electric wire (copper wire) while kneading with a shaft extruder is generally adopted, but in this method, the flame retardant is often in powder form, so the flame retardant in the resin is sufficient. In many cases, they are not uniformly dispersed, and as a result, there is a problem in that the flame resistance of the resulting coated electric wire is not sufficiently exhibited.

[0019]

SUMMARY OF THE INVENTION In view of the above problems of the prior art, an object of the present invention is to provide excellent flame retardancy, and particularly to exhibit an excellent flame retardant effect due to the shape-retaining effect during combustion, and further to increase mechanical strength. Another object of the present invention is to provide a method for producing a covered electric wire, which is capable of efficiently producing a covered electric wire which is excellent in flexibility, elongation, thermal characteristics, and the like and which is also advantageous in separation from a polyvinyl chloride resin.

[0020]

A method for producing a covered electric wire according to the invention as set forth in claim 1 is a masterbatch (A) comprising a polyolefin resin and a layered silicate in an amount of 2 to 50% by weight, a polyolefin resin and a flame retardant. A masterbatch (B) consisting of 20 to 70% by weight and a polyolefin resin composition containing 10 to 90% by weight of a polyolefin resin, a continuous coating layer being formed in the lengthwise direction on the outer periphery of the electric wire. Characterize.

The method for producing a covered electric wire according to a second aspect of the present invention is the method for producing a covered electric wire according to the first aspect, wherein the layered silicate is montmorillonite, swelling mica and / or talc. Characterize.

A method for producing a covered electric wire according to a third aspect of the present invention is the method for producing a covered electric wire according to the first or second aspect, wherein the layered silicate is contained in the crystal structure of the exchangability. It is characterized in that it is a layered silicate in which a metal cation is ion-exchanged with a cationic surfactant to be organized.

A method of manufacturing a covered electric wire according to a fourth aspect of the present invention is the method of manufacturing a covered electric wire according to any one of the first to third aspects, wherein the layered silicate has 6 carbon atoms.
It is characterized by being a layered silicate containing the above alkylammonium ions.

A method for producing a covered electric wire according to a fifth aspect of the present invention is the method for producing a covered electric wire according to any one of the first to fourth aspects, wherein the layered silicate is a wide-angle X-ray diffraction measurement method. The average inter-layer distance of the (001) plane measured by (3) is 3 nm or more, and part or all of the layered silicate is dispersed in 5 layers or less.

The polyolefin resin used in the present invention is a resin obtained by homopolymerizing or copolymerizing an olefin monomer having a polymerizable double bond in the molecule.

The above-mentioned olefinic monomer is not particularly limited, but for example, ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 4-methyl. Examples include α-olefins such as -1-pentene; conjugated dienes such as butadiene and isoprene. These olefinic monomers may be used alone or in combination of two or more kinds.

Specific examples of the above-mentioned polyolefin resin are not particularly limited, but for example, homopolymers of ethylene, copolymers of ethylene and α-olefins other than ethylene copolymerizable with ethylene. , A copolymer of ethylene and (meth) acrylic acid, ethylene and (meth)
Polyethylene resins such as copolymers with acrylic acid esters, copolymers of ethylene and vinyl acetate, copolymers of ethylene and styrene; homopolymers of propylene, other than propylene and propylene copolymerizable with the propylene Polypropylene resins such as copolymers with α-olefins, random copolymers or block copolymers of propylene and ethylene; homopolymers of butene; homopolymers or copolymers of conjugated dienes such as butadiene and isoprene Examples include coalescence. The term "(meth) acrylic acid" used in the present invention means "acrylic acid" or "methacrylic acid".

In the present invention, acid-modified olefin-based oligomers such as maleic anhydride-modified ethylene oligomers and thermoplastic olefin-based elastomers such as copolymer rubber of ethylene and propylene are also the above-mentioned polyolefin-based resins. Included in the category.

Among the above polyolefin-based resins, polyethylene-based resins, polypropylene-based resins, acid-modified olefin-based oligomers and the like are preferably used.
Ethylene homopolymer, copolymer of ethylene and α-olefin other than ethylene copolymerizable with ethylene, copolymer of ethylene and acrylic ester, copolymer of ethylene and vinyl acetate, of propylene A homopolymer, a copolymer of propylene and an α-olefin other than propylene copolymerizable with propylene, a maleic anhydride-modified ethylene oligomer, and the like are more preferably used. These polyolefin resins may be used alone,
Two or more types may be used in combination.

Examples of (meth) acrylic acid and (meth) acrylic acid ester which can be copolymerized with an olefinic monomer include the general formula: CH ₂ ═C (R ¹ ) COO—R ² (wherein
R ¹ represents a hydrogen atom or a methyl group, R ² represents a hydrogen atom, an aliphatic hydrocarbon group, an aromatic hydrocarbon group, and a hydrocarbon group containing a functional group such as a halogen group, an amino group and a glycidyl group. A monovalent group selected from the above).

The (meth) acrylic acid ester represented by the above general formula is not particularly limited, but examples thereof include methyl (meth) acrylate, ethyl (meth) acrylate, and (meth) acrylic acid n. -Propyl, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, sec-butyl (meth) acrylate, t-butyl (meth) acrylate,
Isoamyl (meth) acrylate, (meth) acrylic acid n
-Hexyl, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, lauryl (meth) acrylate, n-tridecyl (meth) acrylate, (meth) Tristyl acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate, allyl (meth) acrylate, (meth)
Vinyl acrylate, benzyl (meth) acrylate, phenyl (meth) acrylate, 2-naphthyl (meth) acrylate, 2,4,6-trichlorophenyl (meth) acrylate, 2,4 (meth) acrylate 6-tribromophenyl, isobornyl (meth) acrylate, 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, diethylene glycol monomethyl ether (meth) acrylate, polyethylene glycol monomethyl (meth) acrylate Ether, polypropylene glycol monomethyl ether (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, 2,3-dibromopropyl (meth) acrylate, 2-chloroethyl (meth) acrylate, 2,2 (meth) acrylate , 2-trifluoroethyl, Hexafluoroisopropyl (meth) acrylate, glycidyl (meth) acrylate, 3-trimethoxysilylpropyl (meth) acrylate, 2-diethylaminoethyl (meth) acrylate, 2-dimethylaminoethyl (meth) acrylate, (meth ) T-butylaminoethyl acrylate and the like can be mentioned. These (meth) acrylic acid esters may be used alone or in combination of two or more kinds.

In the copolymer of ethylene and (meth) acrylic acid, the copolymer of ethylene and (meth) acrylic acid ester, and the copolymer of ethylene and vinyl acetate,
The contents of (meth) acrylic acid, (meth) acrylic acid ester, and vinyl acetate may be appropriately determined depending on the performance required for the polyolefin-based resin composition for forming the coating layer and the coated electric wire, and are not particularly limited. However, it is usually preferably 0.1 to 50% by weight, more preferably 5 to 30% by weight. If the content is less than 0.1% by weight, the effect of improving the flexibility and the elongation of the polyolefin-based resin composition or the covered electric wire may not be sufficiently obtained, and conversely, the content may be 50% by weight. If it exceeds, the thermal characteristics of the polyolefin-based resin composition and the covered electric wire may deteriorate.

When a polyolefin resin having excellent flexibility and elongation is required, a copolymer of ethylene and an α-olefin other than ethylene copolymerizable with the ethylene is generally used. . Since the flexibility and the elongation are remarkably improved by increasing the content of the α-olefin in the copolymer of ethylene and the α-olefin, particularly for the coating layer of the covered electric wire which requires the flexibility and the elongation. It is preferably used as a material. The α-olefin is not particularly limited, and examples thereof include propylene, 1-butene, 1-hexene, 4-methyl-1-pentene, 1-octene and the like. These α-olefins may be used alone or in combination of two or more kinds.

In the above copolymer of ethylene and α-olefin, the content of α-olefin is not particularly limited, but is preferably 0.1 to 50% by weight, more preferably 2%. -40% by weight. When the content is less than 0.1% by weight, sufficient flexibility and elongation of the polyolefin-based resin composition and the coated electric wire for forming the coating layer may not be obtained. When it exceeds 50% by weight, the thermal characteristics of the polyolefin resin composition and the covered electric wire may deteriorate.

The molecular weight and molecular weight distribution (weight average molecular weight / number average molecular weight) of the polyolefin resin used in the present invention are not particularly limited, but the weight average molecular weight is preferably 5,000 to 5,000,000, More preferably, it is 20,000 to 300,000, and the molecular weight distribution is 1.1 to 8
It is preferably 0, more preferably 1.5 to 40
Is.

The polyolefin resin used in the present invention may contain oligomers other than the above acid-modified olefin oligomers for modification of the polyolefin resin, if necessary, within a range that does not impair the achievement of the object of the present invention. Further, thermoplastic elastomers other than the above thermoplastic olefin elastomers may be blended. The thermoplastic elastomers are not particularly limited, but examples thereof include styrene elastomers, urethane elastomers, polyester elastomers and the like. These oligomers and thermoplastic elastomers may be used alone or in combination of two or more kinds. These oligomers and thermoplastic elastomers may be used alone or in combination.

The polyolefin resin used in the present invention may serve as a crystal nucleus for refining crystals as an auxiliary means for homogenizing the physical properties, if necessary, within a range not hindering achievement of the object of the present invention. Nucleating agents, fillers, softeners, plasticizers, surfactants, coupling agents, antioxidants (antiaging agents), heat stabilizers, light stabilizers, UV absorbers,
1 of various additives such as lubricants, antistatic agents, antifogging agents, colorants, etc.
One kind or two or more kinds may be mixed.

The layered silicate used in the present invention means a silicate mineral having an exchangeable metal cation between layers.

The layered silicate is not particularly limited, but examples thereof include montmorillonite, saponite, hectorite, beidellite, stevensite,
Examples include smectite clay minerals such as nontronite, vermiculite, halloysite, swelling mica, talc, and the like, and they are preferably used. Among the above layered silicates, montmorillonite, swelling mica and talc are more preferably used. The layered silicate may be a natural product or a synthetic product. Further, these layered silicates may be used alone or in combination of two or more kinds.

As the layered silicate, it is preferable to use a smectite clay mineral or a swelling mica having a large shape anisotropy effect defined by the following relational expression. By using a layered silicate having a large shape anisotropy effect such as smectite clay mineral or swelling mica, the mechanical strength of the polyolefin resin composition for forming the coating layer becomes more excellent. Shape anisotropy effect = area of crystal surface (A) / area of crystal surface (B) In the above relational expression, crystal surface (A) means a layer surface,
The crystal surface (B) means the side surface of the layer.

The shape of the layered silicate is not particularly limited, but preferably has an average length of 0.01 to 3 μm, a thickness of 0.001 to 1 μm, and an aspect ratio of 20 to 500, More preferably, the average length is 0.0
The thickness is 5 to 2 μm, the thickness is 0.01 to 0.5 μm, and the aspect ratio is 50 to 200.

The exchangeable metal cations existing between the layers of the layered silicate are metal ions such as sodium and calcium existing on the crystal surface of the layered silicate,
Since these metal ions have a cation exchange property with the cationic substance, various cationic substances can be inserted (intercalated) between the crystal layers of the layered silicate.

The cation exchange capacity of the layered silicate is not particularly limited, but is 50 to 200 milliequivalent /
It is preferably 100 g. If the cation exchange capacity of the layered silicate is less than 50 milliequivalents / 100 g, the amount of the cationic substance intercalated between the crystal layers of the layered silicate due to cation exchange is small, so that the crystal layer May not be sufficiently depolarized, and conversely the cation exchange capacity of the layered silicate is 200 milliequivalents / 1
If it exceeds 00 g, the bonding force between the crystal layers of the layered silicate may be too strong, and the crystal flakes may be difficult to peel off.

In the present invention, it is preferable that the exchangeable metal cations existing between the layers of the layered silicate be cation-exchanged with a cationic surfactant to be organically converted to be hydrophobic. By preliminarily hydrophobizing the layers of the layered silicate, the affinity between the layered silicate and the polyolefin resin is increased, and the layered silicate can be more finely dispersed in the polyolefin resin.

The cationic surfactant is not particularly limited, but examples thereof include a quaternary ammonium salt and a quaternary phosphonium salt, which are preferably used. Among the above cationic surfactants, it is possible to sufficiently depolarize the crystal layers of the layered silicate, so
The quaternary ammonium salt having the above alkyl chain (alkyl ammonium salt having 6 or more carbon atoms) is more preferably used.

The quaternary ammonium salt is not particularly limited, but examples thereof include lauryl trimethyl ammonium salt, stearyl trimethyl ammonium salt, trioctyl ammonium salt, distearyl dimethyl ammonium salt, di-hardened tallow dimethyl ammonium salt, Distearyl dibenzylammonium salt, N-polyoxyethylene-N-lauryl-N, N-dimethylammonium salt, etc. are mentioned and used suitably. These quaternary ammonium salts may be used alone or 2
More than one kind may be used in combination.

The quaternary phosphonium salt is not particularly limited, but for example, dodecyltriphenylphosphonium salt, methyltriphenylphosphonium salt, lauryltrimethylphosphonium salt, stearyltrimethylphosphonium salt, trioctylphosphonium salt. , Distearyl dimethyl phosphonium salt, distearyl dibenzyl phosphonium salt and the like, which are preferably used. These quaternary phosphonium salts may be used alone or in combination of two or more kinds.

The layered silicate used in the present invention can be improved in dispersibility in the polyolefin resin by the chemical treatment as described above.

The above-mentioned chemical treatment is (1) a cation exchange method using a cationic surfactant (hereinafter referred to as "chemical modification (1)".
Method)) and can be carried out by various chemical treatment methods shown below. The layered silicate whose dispersibility in the polyolefin resin is improved by the various chemical treatment methods described below, including the chemical modification (1) method, is hereinafter referred to as “organized layered silicate”.

(2) Chemical modification A functional group capable of chemically bonding a hydroxyl group present on the crystal surface of the organically modified layered silicate chemically treated by the method (1), or chemically without the chemical bond. A method of chemically treating with a compound having one or more functional groups having a high affinity at a molecular end (hereinafter, referred to as "Chemical modification (2)".
Law ").

(3) Chemical modification A functional group capable of chemically bonding a hydroxyl group present on the crystal surface of the organically modified layered silicate chemically treated by the method (1), or a chemical group without the chemical bond. A method of chemically treating with a compound having one or more functional groups and reactive functional groups having high affinity at the molecular end (hereinafter,
"Chemical modification (3) method".

(4) Chemical modification (1) A method of chemically treating the crystal surface of the organically modified layered silicate chemically treated by the method (hereinafter, referred to as "chemical modification (4) method"). Note).

(5) Chemical modification In the method (4), the compound having one or more reactive functional groups in addition to the anion site in the molecular chain of the compound having anionic surface activity is chemically treated (hereinafter referred to as "chemical Modification (5) method ").

(6) The organically modified layered silicate chemically treated by any one of the chemical modification (1) method to the chemical modification (5) method is further added with, for example, a maleic anhydride-modified polypropylene resin. Method of using a composition containing a polymer having a functional group capable of reacting with a layered silicate (hereinafter,
"Chemical modification (6) method") and the like. These chemical modification methods may be used alone or in combination of two or more.

In the above-mentioned chemical modification (2), the functional group capable of chemically bonding with a hydroxyl group, or the functional group having a large chemical affinity even if not chemically bonded, is not particularly limited. , Alkoxy group, glycidyl group,
Examples thereof include a functional group such as a carboxyl group (including a dibasic acid anhydride), a hydroxyl group, an isocyanate group, an aldehyde group, and other functional groups having a high chemical affinity with the hydroxyl group.

The compound having a functional group capable of chemically bonding to a hydroxyl group, or the compound having a functional group having a large chemical affinity even if it is not chemically bonded is not particularly limited. The silane compounds, titanate compounds, glycidyl compounds, carboxylic acids, alcohols and the like having the exemplified functional groups are mentioned and are preferably used. These compounds may be used alone,
Two or more types may be used in combination.

The silane compound is not particularly limited, but examples thereof include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, γ-aminopropyltrimethoxysilane and γ-amino. Propylmethyldimethoxysilane, γ-aminopropyldimethylmethoxysilane, γ-
Aminopropyltriethoxysilane, γ-aminopropylmethyldiethoxysilane, γ-aminopropyldimethylethoxysilane, methyltriethoxysilane, dimethyldimethoxysilane, trimethylmethoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, N-β- (Aminoethyl) γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) γ-aminopropyltriethoxysilane, N-β- (aminoethyl) γ-aminopropylmethyldimethoxysilane, octadecyltrimethoxysilane, octadecyl Triethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypro Le triethoxysilane and the like, is preferably used. These silane compounds may be used alone or in combination of two or more kinds.

Further, the chemical modification (4) method and the chemical modification (5)
In the method, the compound having anionic surface activity and / or the compound having anionic surface activity and having at least one reactive functional group other than the anion site in the molecular chain is a layered silicic acid by ionic interaction. It may be any compound as long as it can chemically treat the salt, and is not particularly limited, and examples thereof include sodium laurate, sodium stearate, and sodium oleate.
A higher alcohol sulfuric acid ester salt, a secondary higher alcohol sulfuric acid ester salt, an unsaturated alcohol sulfuric acid ester salt, etc. are mentioned and used suitably. These compounds may be used alone or in combination of two or more kinds.

The layered silicate used in the present invention (the layered silicate described below includes the above-mentioned organized layered silicate) was measured by a wide-angle X-ray diffraction measurement method (001).
It is preferable that the average interlayer distance of the surface is 3 nm or more, and a part or all of the layered silicate is dispersed in 5 layers or less. More preferably, the average interlayer distance is 6 or less.
It is a layered silicate having a thickness of at least nm and a part or all of which is dispersed in 5 layers or less. The average interlaminar distance of the layered silicate referred to in the present invention means the average interlaminar distance when the fine flaky crystals of the layered silicate are formed into a layer, and the X-ray diffraction peak and the transmission electron microscope photograph, that is, , Wide-angle X-ray diffraction measurement method.

When the average interlaminar distance of the layered silicate is 3 nm or more and a part or all of the layered silicate is dispersed in 5 layers or less, a masterbatch (A) described below comprising a polyolefin resin and a layered silicate is obtained. The contained polyolefin resin composition exhibits various properties such as excellent flame retardancy, mechanical strength, and thermal characteristics.

The fact that the average interlayer distance of the layered silicate is 3 nm or more means that the layers of the layered silicate are cleaved to 3 nm or more, and part or all of the layered silicate is cleaved. Dispersed in 5 layers or less means
This means that a part or all of the layered silicate laminate is widely dispersed, which means that the interaction between the layers of the layered silicate is weakened.
The above effect can be obtained.

Particularly, the average interlayer distance of the layered silicate is 6 nm.
When it is above, and a part or all is dispersed in 5 layers or less, the polyolefin resin composition containing the masterbatch (A) consisting of the polyolefin resin and the layered silicate is remarkably excellent in flame retardance. Properties, mechanical strength, thermal characteristics, and other properties are exhibited. Further, when the average interlayer distance of the layered silicate is 3 nm or more, preferably 6 nm or more, the crystal thin layer of the layered silicate is separated into layers, and the interaction of the layered silicate is so weak that it can be almost ignored.
There is an advantage that the dispersed state of the crystal flakes constituting the layered silicate in the polyolefin resin progresses toward the stabilization of crushing.

The fact that part or all of the layered silicate is dispersed in 5 layers or less means that 10% or more of the layered silicate is dispersed in 5 layers or less. This means preferable, and more preferably, 20% or more of the layered silicate is dispersed in 5 layers or less.

The number of laminated layered silicates is preferably divided into 5 layers or less, whereby the above effect can be obtained, but more preferably 3 or less layers are divided. It is particularly preferable that the thin film is formed into a single layer.

The average interlayer distance of the layered silicate is 3 nm or more, and a part or all of the layered silicate is dispersed in 5 layers or less, that is, the layered silicate is highly dispersed in the polyolefin resin. In such a state, the interfacial area between the polyolefin resin and the layered silicate increases, and the average distance between the crystal flakes of the layered silicate decreases.

When the interfacial area between the polyolefin resin and the layered silicate increases, the degree of restraint of the polyolefin resin on the surface of the layered silicate increases, and the mechanical strength such as elastic modulus improves. Further, when the degree of restraint of the polyolefin resin on the surface of the layered silicate is increased, the melt viscosity is increased and the moldability is also improved. Furthermore, the gas barrier property can be exhibited by the baffle effect of the layered silicate.

On the other hand, when the average distance between the crystal flakes of the layered silicate is small, it becomes easy to form a sintered body due to the movement of the crystal flakes of the layered silicate during combustion. That is, the polyolefin resin composition in which the crystal flakes of the layered silicate are highly dispersed so that the average interlayer distance is 3 nm or more facilitates the formation of a sintered body that can be a flame retardant coating. Since this sintered body is formed at an early stage during combustion, it can block not only the supply of oxygen from the outside, but also the combustible gas generated by combustion. The coating layer formed from exhibits excellent flame retardancy.

The flame retardant used in the present invention may be any flame retardant as long as it can impart flame retardancy to the polyolefin resin, but it is preferably a non-halogen flame retardant, and specific examples thereof. Examples thereof include, but are not particularly limited to, metal hydroxides, phosphorus compounds, melamine derivatives, and the like, and are preferably used. Among them, metal hydroxides are more preferably used. These flame retardants may be used alone or in combination of two or more.

The metal hydroxide is not particularly limited, but examples thereof include magnesium hydroxide, aluminum hydroxide, dawsonite, calcium aluminide, dihydrate gypsum, calcium hydroxide, and the like. Among them, magnesium hydroxide and aluminum hydroxide are more preferably used. These metal hydroxides may be used alone or in combination of two or more kinds. When two or more kinds of metal hydroxides are used together, each starts a decomposition dehydration reaction at different temperatures.
A higher flame retardant effect can be obtained. Further, these metal hydroxides are surface-treated with a surface treatment agent such as a silane coupling agent, a titanium coupling agent, an aluminum coupling agent, a polyvinyl alcohol-based surface treatment agent, a glycidyl compound-based surface treatment agent. May be.

The metal hydroxide exhibits an effect of lowering the temperature of the combustion field and extinguishing the fire by causing an endothermic dehydration reaction under the high heat of combustion and absorbing heat to release water molecules. Therefore, by adding both the layered silicate and the metal hydroxide to the polyolefin resin, the flame retardant effect of the polyolefin resin composition for forming the coating layer is further increased. This is because the flame-retardant effect due to the film formation during the combustion of the layered silicate and the flame-retardant effect due to the endothermic dehydration reaction of the metal hydroxide competitively promote each other.

In the method for producing a covered electric wire according to the present invention,
As a material for forming the coating layer, 2 to 50% by weight of the master batch (A) composed of the polyolefin resin and the layered silicate, and 20 to 70 of the master batch (B) composed of the polyolefin resin and the flame retardant. A polyolefin resin composition containing 10% by weight and 10 to 90% by weight of the polyolefin resin is used.

The mixing ratio of the polyolefin resin and the layered silicate in the masterbatch (A) is not particularly limited, but the masterbatch (A) is contained in the polyolefin resin composition in an amount of 2 to 50% by weight. %, The mixing ratio is preferably 0.1 to 100 parts by weight of the layered silicate, and more preferably 1 to 20 parts by weight of the layered silicate, based on 100 parts by weight of the total amount of the polyolefin resin. It is a mixing ratio which becomes a weight part.

When the mixing ratio of the layered silicate is less than 0.1 part by weight based on 100 parts by weight of the total amount of the polyolefin resin, the above-mentioned difficulty due to the layered silicate being contained in the polyolefin resin composition. The flame effect may not be sufficiently obtained, and conversely the total amount of polyolefin resin is 10
When the mixing ratio of the layered silicate is more than 100 parts by weight with respect to 0 parts by weight, the flexibility and elongation of the polyolefin resin composition are decreased, and the specific gravity of the polyolefin resin composition is high. It may become too difficult to separate from the polyvinyl chloride resin.

The mixing ratio of the polyolefin resin and the flame retardant in the masterbatch (B) varies depending on the kind of the flame retardant and is not particularly limited, but the flame retardant is a metal hydroxide. In some cases, when the masterbatch (B) is contained in the polyolefin resin composition in an amount of 20 to 70% by weight, the total amount of the polyolefin resin is 1
The mixing ratio is preferably 10 to 70 parts by weight with respect to 00 parts by weight, and more preferably 20 to 50 parts by weight with respect to the flame retardant.

If the mixing ratio of the flame retardant is less than 10 parts by weight with respect to 100 parts by weight of the total amount of the polyolefin resin, sufficient flame retardancy may not be obtained, and conversely, the total amount of the polyolefin resin may be insufficient. When the mixing ratio is such that the flame retardant exceeds 70 parts by weight with respect to 100 parts by weight, the flexibility and the elongation of the polyolefin-based resin composition decrease,
In addition, the specific gravity may become too high, and it may be difficult to separate it from the polyvinyl chloride resin.

The method for producing the masterbatch (A) and the masterbatch (B) is not special and, for example, using a known kneader such as a screw extruder or a Banbury mixer, at room temperature or under heating. By uniformly kneading the respective predetermined amounts of the polyolefin resin and the layered silicate in the case of the masterbatch (A) and the respective predetermined amounts of the polyolefin resin and the flame retardant in the case of the masterbatch (B), A desired masterbatch (A) or masterbatch (B) can be prepared.

The content of the masterbatch (A) in the polyolefin resin composition used in the present invention is less than 2% by weight and / or the content of the masterbatch (B) is 20% by weight. When it is less than, flame retardancy and mechanical strength of the coating layer formed from the polyolefin-based resin composition and the composition, thermal properties, etc. become insufficient,
On the contrary, when the content of the masterbatch (A) in the polyolefin resin composition exceeds 50% by weight and / or the content of the masterbatch (B) exceeds 70% by weight, the polyolefin resin composition Also, the flexibility and the elongation of the coating layer formed from the composition decrease, and the specific gravity becomes too high, which makes it difficult to separate the polyvinyl chloride resin from the polyvinyl chloride resin.

When the content of the polyolefin resin in the polyolefin resin composition used in the present invention is less than 10% by weight, the polyolefin resin composition and the coating layer formed from the composition are fragile. On the contrary, when the content of the polyolefin resin in the polyolefin resin composition exceeds 90% by weight, the flame retardancy and mechanical strength of the polyolefin resin composition and the coating layer formed from the composition, Insufficient thermal properties, etc.

The polyolefin resin composition used in the present invention may contain, for example, a flame retardant aid, a filler, a softening agent, a plasticizer, a surfactant, if necessary, within a range that does not hinder the achievement of the object of the present invention. , One or more of various additives such as a coupling agent, an antioxidant (anti-aging agent), a heat stabilizer, a light stabilizer, an ultraviolet absorber, a lubricant, an antistatic agent, an antifogging agent, and a colorant. May be blended.

The flame retardant aid is not particularly limited, but examples thereof include metal oxides, carbon black, silicone oil, and silicone-acryl composite rubber, and they are preferably used. These flame retardant aids may be used alone or in combination of two or more.

The method for producing the above-mentioned polyolefin resin composition is not special and, for example, using a known kneader such as a screw extruder or a Banbury mixer, at room temperature or under heating, the master batch (A ), A masterbatch (B) and a predetermined amount of a polyolefin resin,
One or two of various additives that are blended as needed
By uniformly kneading each predetermined amount of more than one kind,
A desired polyolefin resin composition can be produced.

In the method for producing a covered electric wire according to the present invention,
A coating layer made of the above polyolefin resin composition is continuously formed on the outer peripheral portion of the electric wire (copper wire) in the longitudinal direction.

The method of forming the coating layer is not special, and for example, a polyolefin resin composition prepared in advance containing predetermined amounts of the masterbatch (A), the masterbatch (B) and the polyolefin resin can be used. Alternatively, a predetermined amount of each of the masterbatch (A), the masterbatch (B), and the polyolefin-based resin constituting the polyolefin-based resin composition is melt-kneaded using a uniaxial or biaxial extruder, and the melt is kneaded to the outer peripheral portion of the electric wire. A desired coating layer can be formed by continuously performing extrusion coating in the depth direction. The masterbatch (A), masterbatch (B), polyolefin-based resin and polyolefin-based resin composition are preferably pelletized by a conventional method before use.

[0084]

In the method for producing a covered electric wire according to the present invention, in the polyolefin resin composition for forming the covering layer,
Since the layered silicate and the flame retardant are not blended in the state as they are, but are blended in the state of the masterbatch (A) and the masterbatch (B) in advance, even when the layered silicate and the flame retardant are in powder form. The layered silicate and flame retardant are sufficiently and uniformly dispersed in the polyolefin resin. Therefore,
The obtained covered electric wire exhibits excellent flame retardancy.

Further, the above polyolefin resin composition is
Since the specific amounts of the masterbatch (A), the masterbatch (B) and the polyolefin resin are contained, the obtained coated electric wire has not only excellent flame retardancy but also mechanical strength, flexibility and elongation. In addition, it has excellent thermal characteristics and is advantageous in the separation from the polyvinyl chloride resin.

Further, according to the manufacturing method of the present invention, it is possible to efficiently manufacture a covered electric wire having the above-mentioned various excellent characteristics.

[0087]

BEST MODE FOR CARRYING OUT THE INVENTION The following examples are given to illustrate the present invention in more detail, but the present invention is not limited to these examples. In addition, "part" in an Example means a "weight part."

(Example 1) Ethylene was added in a twin-screw extruder.
Ethyl acrylate copolymer (trade name "A4250", manufactured by Nippon Polyolefin Co., Ltd.) 7.6 parts, maleic anhydride modified ethylene oligomer (trade name "ER507L-5" manufactured by Japan Polyolefin Co., Ltd.) 46.2 parts and distearyl 46.2 parts of montmorillonite (trade name "New S Ben D", manufactured by Hojun Co., Ltd.) that has been subjected to an organic treatment with dimethyl quaternary ammonium salt is fed, melt-kneaded at a set temperature of 180 ° C., and extruded in a strand shape The extruded strand was pelletized by a pelletizer to prepare a masterbatch (A). Similarly, a masterbatch (B) comprising 40.0 parts of ethylene-ethyl acrylate copolymer "A4250" and 60.0 parts of magnesium hydroxide (trade name "Kisuma 5PH", manufactured by Kyowa Chemical Industry Co., Ltd.).
Was produced.

Then, 16.6 parts of the above masterbatch (A), 60.0 parts of the above masterbatch (B) and ethylene-ethyl acrylate co-weighed in a single-screw extruder equipped with a wire coating die. A polyolefin resin composition composed of 23.4 parts of the coalesced "A4250" is fed, melt-kneaded and extruded at a set temperature of 180 ° C, and a coating layer is continuously formed on the outer peripheral portion of the electric wire (copper wire) in the length direction. Then, a coated electric wire was manufactured. Further, pellets of the above polyolefin resin composition were prepared in the same manner as above, and the pellets were
It was pressed by a hot press whose temperature was adjusted to ° C to prepare a plate-shaped molded body having a thickness of 3 mm.

Example 2 The composition of the masterbatch (B) was changed from ethylene-ethyl acrylate copolymer "A4250".
30.0 parts and magnesium hydroxide "Kisuma 5PH" 7
The masterbatch (A) 40.0 having 0.0 parts and the composition of the polyolefin resin composition produced in Example 1
Part, the above masterbatch (B) 30.0 parts, and ethylene-ethyl acrylate copolymer "A4250" 30.0 parts, except that the amount was 30.0 parts and the production of the coated electric wire was performed in the same manner as in Example 1. The plate-shaped molded body of was produced.

Example 3 The composition of the masterbatch (A) was changed to ethylene-ethyl acrylate copolymer "A4250".
7.6 parts, maleic anhydride modified ethylene oligomer "E
R507L-5 "46.2 parts, distearyl dimethyl 4
23.1 parts of montmorillonite "New S-Ben D" and talc (trade name "P-6", manufactured by Nippon Talc Co., Ltd.) that have been organically treated with a high-grade ammonium salt, and a polyolefin resin composition Except that the composition of the product was 16.6 parts of the above masterbatch (A), 60.0 parts of the masterbatch (B) prepared in Example 1 and 23.4 parts of ethylene-ethyl acrylate copolymer "A4250". In the same manner as in Example 1, a coated electric wire was manufactured and a plate-shaped molded body having a thickness of 3 mm was manufactured.

Example 4 The composition of the masterbatch (A) was changed to maleic anhydride-modified ethylene oligomer “ER507”.
L-5 "53.8 parts, montmorillonite" New S-Ben D "34.7 parts and talc" P-6 "1 which have been treated with a distearyl dimethyl quaternary ammonium salt.
1.5 parts, and the composition of the polyolefin-based resin composition was 9.0 parts of the above masterbatch (A), 30.0 parts of the masterbatch (B) prepared in Example 2 and ethylene-
A coated electric wire and a plate-shaped molded product having a thickness of 3 mm were produced in the same manner as in Example 1 except that 61.0 parts of ethyl acrylate copolymer "A4250" was used.

(Comparative Example 1) 7.6 parts of ethylene-ethyl acrylate copolymer "A4250", maleic anhydride modified ethylene oligomer "ER507L-" were prepared without preparing master batch (A) and master batch (B).
5 "46.2 parts, montmorillonite" New S-Ben D "46.2 parts organically treated with distearyldimethyl quaternary ammonium salt and magnesium hydroxide" Kisuma 5PH "40.0 parts polyolefin resin In the same manner as in Example 1 except that the composition was used,
A coated electric wire was manufactured and a plate-shaped molded body having a thickness of 3 mm was manufactured.

(Comparative Example 2) 50.0 parts of ethylene-ethyl acrylate copolymer "A4250" and magnesium hydroxide "Kisuma 5PH" 50.50 were prepared without preparing masterbatch (A) and masterbatch (B). Manufacture of a coated electric wire and a thickness of 3 m in the same manner as in Example 1 except that 0 part of the polyolefin resin composition was used.
A plate-shaped molded body of m was produced.

(Comparative Example 3) 60.0 parts of a linear low-density polyethylene resin (trade name "EV630A", manufactured by Nippon Polyolefin Co., Ltd.) and water were prepared without preparing a masterbatch (A) and a masterbatch (B). A coated electric wire and a plate-shaped molded body having a thickness of 3 mm were produced in the same manner as in Example 1 except that a polyolefin resin composition containing 40.0 parts of magnesium oxide "Kisuma 5PH" was used. .

(Comparative Example 4) 50.0 parts of ethylene-ethyl acrylate copolymer "A4250" and magnesium hydroxide "Kisuma 5PH" 49. were prepared without preparing masterbatch (A) and masterbatch (B). Production of a covered electric wire and production of a plate-shaped molded body having a thickness of 3 mm were carried out in the same manner as in Example 1 except that a polyolefin resin composition consisting of 0 part and 1.0 part of cupric oxide was used. It was

The coated electric wires obtained in Examples 1 to 4 and Comparative Examples 1 to 4 were subjected to a 60-degree tilt flame retardancy test by the following method. Further, Examples 1 to 4 and Comparative Examples 1 to
The tensile elongation of the plate-shaped molded product obtained in Comparative Example 4 was measured by the following method. The results are shown in Table 1.

60 degree tilt flame retardancy test: JIS C-30
In accordance with No. 05, a 60-degree tilt flame retardancy test was performed on the coated electric wire, and a pass or fail was determined. Tensile elongation: JIS K-6251 “Tensile test method for vulcanized rubber” under an atmosphere of temperature 20 ° C. and humidity 50% RH
The elongation at break (%) of the dumbbell-shaped No. 3 test piece cut out from the plate-shaped molded product (thickness: 3 mm) was measured in accordance with.

[0099]

[Table 1]

As is clear from Table 1, the coated electric wires of Examples 1 to 4 produced by the manufacturing method of the present invention are all 6
It passed the 0-degree tilt flame retardancy test and developed excellent flame retardancy. In addition, the plate-shaped molded bodies made of the polyolefin resin composition used for the coating layers of the coated electric wires of Examples 1 to 4 all exhibited excellent tensile elongation.

On the other hand, the masterbatch (A) and the masterbatch (B) were not prepared, and the coating layer was formed from the polyolefin resin composition in which the layered silicate and magnesium hydroxide (flame retardant) were blended as they were. The formed coated electric wire of Comparative Example 1 failed the 60-degree tilt flame retardancy test and had poor flame retardancy. In addition, the plate-shaped molded product made of the above polyolefin-based resin composition was inferior in tensile elongation.

Further, Comparative Examples 2 to 4 in which the coating layer was formed from the polyolefin-based resin composition in which neither the masterbatch (A) nor the masterbatch (B) was prepared and the layered silicate was not mixed All the coated electric wires failed the 60-degree tilt flame retardancy test, and the flame retardance was poor. Further, a plate-shaped molded article made of the above polyolefin-based resin composition,
In each case, the tensile elongation was inferior.

[0103]

As described above, according to the manufacturing method of the present invention, the flame retardancy is excellent, and particularly the shape retaining effect at the time of combustion exerts an excellent flame retarding effect, and further, the mechanical strength and the flexibility are improved. , Even when using a production equipment having a relatively weak kneading force, such as a single-screw extruder, for a covered electric wire that is excellent in elongation, thermal characteristics, etc. and is also advantageous in separation from a polyvinyl chloride resin, It can be manufactured efficiently.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ identification code FI theme code (reference) H01B 3/44 H01B 3/44 GMP 7/295 7/34 B (72) Inventor Hideyuki Takahashi Osaka Prefecture Sekisui Chemical Co., Ltd. 2-1 Hyakusan, Shimamoto-cho, Mishima-gun (72) Inventor Koji Taniguchi 2-1 Hyakusan 2-1, Shimamoto-cho, Mishima-gun, Osaka Prefecture F-term (reference) 4F070 AA13 AA15 AA16 AC14 AC15 AC27 AE01 AE07 FA03 FA13 FB03 4J002 BB051 BB061 BB071 BB111 BB121 BB211 DE077 DE087 DE147 DE187 DG057 DJ006 DJ046 DJ056 FB106 FB236 FD137 5G305 AA02 AB25 BA02 CA25 CA03 CD02 CD02 CD02 CD02 CD02 CD02 CD02 CD02 CD02 5

Claims (5)

[Claims] 1. A masterbatch (A) containing 2 to 50% by weight of a polyolefin resin and a layered silicate, and a masterbatch (B) containing a polyolefin resin and a flame retardant.
20-70% by weight and polyolefin resin 10-90
A method for producing a covered electric wire, characterized in that a covering layer made of a polyolefin-based resin composition containing wt% is continuously formed in the outer peripheral portion of the electric wire in the length direction. 2. The method for producing a covered electric wire according to claim 1, wherein the layered silicate is montmorillonite, swelling mica and / or talc. 3. The layered silicate is a layered silicate formed by exchanging exchangeable metal cations contained in its crystal structure by ion exchange with a cationic surfactant. Item 3. A method for manufacturing a covered electric wire according to Item 2. 4. The method for producing a covered electric wire according to claim 1, wherein the layered silicate is a layered silicate containing an alkylammonium ion having 6 or more carbon atoms. 5. A layered silicate in which the layered silicate has an average inter-layer distance of 3 nm or more on the (001) plane measured by a wide-angle X-ray diffraction measurement method, and a part or all of which is dispersed in 5 layers or less. It is salt, The manufacturing method of the covered electric wire in any one of Claims 1-4.