JP2002231070A - Fire-retardant cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fire-retardant cable (particularly elevator cable) that has a superior fire-retardancy and is easy to be bent and has no possibility of generating toxic gases in waste disposal incineration. SOLUTION: This is a flat type cable that has a plurality of cable cores 2 made of an assembly of one piece of insulating lead wire or plural pieces of insulating lead wires, and the plural cable cores 2 are arranged in a row and covered by a sheath 3 and made in one body. The above sheath 3 or the insulating body of the above sheath and the insulating lead wires are formed of a fire-retardant polyolefinic resin composite that contains 10-70 pts.wt. of metal hydroxide system fire retardant and 2-30 pts.wt. of swelling clay mineral in 100 pts.wt. of polyolefinic resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a flame-retardant cable, particularly to a flat flame-retardant cable suitable for an elevator cable.

[0002]

2. Description of the Related Art Conventionally, insulating materials (sheaths, insulating conductors of insulated wires) of cables for various applications laid in buildings such as buildings are required to have flame retardancy. , PVC) have been used. However, in recent years, since PVC is suspected to cause toxic gases such as Diokin and hydrogen chloride gas during cable incineration, insulating materials for cables have recently been made of a flame retardant made of a polyolefin resin mixed with a flame retardant made of an inorganic metal compound. Polyolefin-based resin compositions (hereinafter, also abbreviated as flame-retardant polyolefins).

However, among cables laid in a building, an elevator cable 10 shown in FIG. 4, that is, a control signal between a control panel (control panel) 12 and an elevator gauge 13 in a machine room 11 of an elevator is shown. Flame-retardant polyolefin is not used as an insulating material of a cable for performing transmission, power supply for lighting, and the like, and PVC is still used.

[0004] That is, as shown in FIG. 4, one end of the elevator cable 10 is normally connected and fixed to the lower end of the elevator gauge 13, and the other end is connected to the elevator hall 1.
4 is supported and fixed at a position slightly higher than the half height position in the inside, and is laid in a state of being bent and suspended in a U-shape (extending up to the machine room 11 by another cable separately laid, or The elevator cable 13 is further extended and laid out from the support fixing portion.), And moves in a bent state as the elevator gauge 13 moves up and down. Therefore,
If the cable is not flexible, it will be difficult to lay the cable in a U-shape without twisting (the narrower the width W of the elevator hall, the more difficult it becomes).
Even if the cable can be laid, the elevator cable 10 is strongly pulled by its own weight during the movement in the bent state, and is repeatedly subjected to bending stress, so that the cable may be greatly twisted and the conductor in the cable may be broken. Is generated. However, conventional flame-retardant polyolefin is hard because it contains a relatively large amount of inorganic metal compound (flame retardant). If this is used for insulation, the cable becomes less flexible, so it is used for elevator cables. could not.

[0005] However, with increasing awareness of environmental issues in recent years, there has been an increasing demand for dehalogenating all cables in buildings, and dehalogenation of elevator cables has become an important issue. .

[0006]

SUMMARY OF THE INVENTION In view of the above circumstances, the present invention has excellent flame retardancy, but is relatively flexible and easy to bend, and there is no concern about generation of toxic gas during waste incineration. It is intended to provide a flame-retardant cable. Another object of the present invention is to provide a flame-retardant cable particularly suitable for an elevator cable.

[0007]

Means for Solving the Problems In order to achieve the above object, the present inventors have conducted intensive studies, and as a result, a combination of a polyolefin-based resin, a metal hydroxide-based flame retardant and a swellable clay mineral has been found to be sufficient. A flame-retardant polyolefin-based resin composition having excellent flame-retardant properties and higher flexibility than before is obtained. By using this for at least the sheath of a cable, sufficient flame-retardant properties and flexibility (easy-to-use) are obtained. The inventors have found that a cable having both flexibility and flexibility can be obtained, and have completed the present invention. That is, the present invention is as follows.

(1) A flat cable in which a plurality of cable cores each composed of one insulated conductor or an aggregate of a plurality of insulated conductors are provided, and the plurality of cable cores are arranged in parallel, covered with a sheath, and integrated. The sheath, or the insulator of the sheath and the insulated conductor, may be composed of 10 to 70 parts by weight of a metal hydroxide flame retardant and 2 to 30 parts by weight of a swellable clay mineral per 100 parts by weight of a polyolefin resin. A flame-retardant cable formed of a flame-retardant polyolefin-based resin composition containing: (2) The flame-retardant cable according to the above (1), wherein the polyolefin resin is an ethylene-ethyl acrylate copolymer. (3) The flame-retardant cable according to the above (1) or (2), wherein the flame-retardant polyolefin resin composition has an oxygen index of 22 or more and a tensile modulus of 30 MPa or less. (4) The specific gravity of the flame-retardant polyolefin resin composition is 1.
The flame-retardant cable according to any one of the above (1) to (3), which is 1 to 1.3. (5) The above (1), wherein the flame-retardant polyolefin-based resin composition has a tensile strength of 10 MPa or more and an elongation of 350% or more.
The flame-retardant cable according to any one of (1) to (4). (6) The flame-retardant cable according to any one of (1) to (5), wherein the cable core is formed by twisting a plurality of insulated conductors. (7) The above (1) to (6) for use in elevator cables
The flame-retardant cable according to any one of the above.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described more specifically. The flame-retardant cable of the present invention (hereinafter, also simply referred to as a cable) has a plurality of cable cores formed of one insulated conductor or an aggregate of a plurality of insulated conductors, and the plurality of cable cores are arranged in parallel. A flat cable which is covered and integrated with a sheath, wherein at least the sheath of the cable insulating material (sheath, insulator of the insulated wire) is metal hydroxide of 10 to 70 parts by weight per 100 parts by weight of the polyolefin resin. It is characterized by being formed of a flame-retardant polyolefin-based resin composition containing a substance-based flame retardant and 2 to 30 parts by weight of a swellable clay mineral.

FIG. 1 shows a specific example of the flame-retardant cable of the present invention. The cable 5 includes six cable cores 2 each formed of an aggregate of six insulated conductors 1 arranged in parallel, and the six cable cores 2 are formed of a sheath 3 made of the flame-retardant polyolefin resin composition having the specific composition. Covered and integrated (partitions are formed between the second and third cables and between the fourth and fifth cables) and flat (the cross section in the direction perpendicular to the longitudinal direction of the cable is flat). It has a structured cable. Reference numeral 4 in FIG. 1 is a core material of the cable core 2 made of a string made of a synthetic resin such as polypropylene.

The cable 5 of the example is intended for an elevator cable. The cable 5 has six cable cores, and each cable core is composed of six insulated conductors 1. In the cable of the present invention, the number of cable cores and the number of insulated conductors forming the cable core are appropriately determined according to the use and usage of the cable, and are not particularly limited. Further, the cable core may be constituted by one relatively large-diameter insulated conductor. In addition, a cable having a cable core in which a linear body other than an insulated conductor such as an optical fiber is assembled together with an insulated conductor, or a flat cable in which a linear body other than an insulated conductor such as an optical fiber is covered with a sheath together with a cable core. The cable of the present invention also has a structure in which at least the sheath is formed of the flame-retardant polyolefin-based resin composition having the specific composition.

In the cable according to the present invention, the flame-retardant polyolefin resin composition having the above specific composition used for the insulating material (10 to 70 parts by weight of a metal hydroxide-based flame retardant and 100 parts by weight of a polyolefin resin and a swellable clay) Minerals 2-3
The composition containing 0 parts by weight) is relatively soft (flexible) while having sufficient flame retardancy due to the specific composition, and furthermore does not generate harmful gas even when incinerated. A resin composition is realized.

Here, "sufficient flame retardancy" means that the oxygen index (LOI) shown below is 22 or more (preferably 25 or more).
And "soft (flexible)" means
The tensile elastic modulus shown below indicates 30 MPa or less.

[Oxygen Index (LOI)] JIS K 72
The oxygen index is measured for a test piece having a thickness of 3 mm and a width of 6.5 mm (A-1 test piece) in accordance with the regulations of No. 01. Note that the oxygen index is a numerical value representing the minimum oxygen concentration required for the material to sustain combustion by volume%.

[Tensile modulus] According to JIS K 7113, the tensile strength is determined by calculation using the stress when the interval between the marked lines attached to the test piece (No. 2 test piece) is extended by 2%.

In the flame-retardant cable according to the present invention, at least the sheath of the insulating material (sheath, insulator of the insulated wire) is
A cable having not only good flame retardancy but also relatively flexible and easy to bend by being formed of a flame-retardant polyolefin resin composition having softness while having sufficient flame retardancy It can be suitably used for a cable that requires flexibility (flexibility). When the cable of the present invention is used for an elevator cable, it can be bent and attached in a U-shape without twisting even in a relatively narrow space. Is hard to be twisted, and sufficient durability can be obtained. In addition, without impairing the flexibility of the cable,
In order to further improve the flame retardancy, it is preferable to form not only the sheath but also the insulator of the insulated conductor with the flame-retardant polyolefin-based resin composition having the specific composition.

In the cable of the present invention, the thickness of the sheath (the thickness of the minimum thickness portion covering the core of the sheath cable (D in FIG. 1)), the thickness (outer diameter) of the conductor in the insulated conductor, and the insulation The finished dimensions of the cable, such as the thickness of the insulator in the conductor, are set according to the standard (JIS, etc.) for the intended use of the cable. For example, in the case of an elevator cable, it is set to a range specified in JIS C3408.

As described above, the flame-retardant cable of the present invention is characterized in that both the sheath and the insulator of the insulated conductor are made of the flame-retardant polyolefin-based resin composition having the above-mentioned specific composition in view of the flame retardancy of the cable. It is preferable to form them. However, when the insulator of the insulated conductor is not formed of the flame-retardant polyolefin-based resin composition having the specific composition described above, for example, ethylene-propylene rubber is preferred from the viewpoint of cable flexibility (flexibility). Halogen-free rubber material such as ethylene-vinyl acetate copolymer (E) having a relatively high content of vinyl acetate (VA)
VA), an ethylene-ethyl acrylate copolymer (EEA) having a relatively high content ratio of ethyl acrylate (EA)
Etc. are used.

In the flame-retardant cable according to the present invention, when the cable core is composed of a plurality of insulated conductors, a stranded wire obtained by twisting a plurality of insulated conductors from the viewpoint of flexibility (flexibility) of the cable. It is preferred to have a structure. The conductor in the insulated conductor may be a single thick wire or a stranded wire obtained by twisting thin wires, but the flexibility (flexibility) of the cable
In view of the above, a stranded wire is preferable. The material of the insulated conductor is appropriately selected from known materials (copper and its alloy wire, aluminum and its alloy wire, or those obtained by plating these wires, etc.) according to the use of the cable. .
In the case of an elevator cable, a flexible soft copper stranded wire, a tin-plated flexible soft copper stranded wire, or the like is preferable.

When the cable of the present invention is used for an elevator cable, the cable is laid in a state of being bent in a U-shape and suspended (a state of being strongly pulled by its own weight). A cable structure in which a reinforcing wire is embedded in the sheath (the strength of the cable is increased by the reinforcing wire) may be adopted. FIG. 2 shows a specific example thereof, in which a reinforcing wire (a wire formed by twisting steel wires) 6 is buried in a gap between a plurality of parallel cable cores 1 (a portion consisting of only the sheath 3). . As the reinforcing wire, a wire obtained by twisting steel wires of carbon steel, a wire obtained by twisting steel wires of stainless steel, or the like is preferable, and the wire diameter is preferably about 1 to 10 mm.

The flame-retardant cable of the present invention is relatively flexible and easy to bend. The degree of the change depends on the number of insulated conductors and the number of cable cores. ) Is 0.01 to
0.5 N · m ² , preferably 0.03 to 0.08 N · m ²
Can be realized, and an elevator cable having substantially the same flexibility (flexibility) as a conventional elevator cable formed of PVC can be obtained.

The polyolefin resin constituting the flame-retardant polyolefin resin composition used in the present invention is a polyolefin resin containing no halogen atom in the molecule.
For example, polyethylene resin, polypropylene resin,
Examples thereof include a poly (1-butene) -based resin, a polypentene-based resin, and a mixture thereof, and these may be used alone or in combination of two or more. Among these, it is preferable to use a polyethylene resin from the viewpoint of the flexibility of the resin composition.

As the polyethylene resin, any of homopolymers of ethylene (low density, medium density, high density), copolymers containing ethylene as a main component, and mixtures thereof can be used. A copolymer having a main component is preferable, and examples of the copolymer include ethylene and α.
-Olefin copolymers. Examples of the α-olefin include propylene, 1-hexene, and 4-methyl-1-.
Examples thereof include pentene, 1-octene, 1-butene, and 1-pentene. Further, a copolymer of ethylene and a vinyl monomer other than the α-olefin can also be used, and examples thereof include an ethylene-vinyl acetate copolymer (EVA) and an ethylene-ethyl acrylate copolymer (EEA). . Among such ethylene-based copolymers, ethylene-vinyl acetate copolymer (EVA) and ethylene-ethyl acrylate copolymer (EEA) are preferred, and ethylene-ethyl acrylate copolymer (EEA) is particularly preferred. It is. In these ethylene-vinyl acetate copolymer (EVA) and ethylene-ethyl acrylate copolymer (EEA), vinyl acetate (V
A) or a content of ethyl acrylate (EA) of 10
The content of vinyl acetate (VA) or ethyl acrylate (EA) is preferably 15 to 20% by weight.
% By weight are particularly preferred.

The polypropylene resin may be any one of a propylene homopolymer, a copolymer containing propylene as a main component, and a mixture thereof. Examples of the copolymer containing propylene as a main component include, for example, a propylene-α-olefin copolymer containing propylene as a main component.
Examples thereof include 1-hexene, 4-methyl-1-pentene, 1-octene, 1-butene, and 1-pentene.

As the metal hydroxide-based flame retardant, a known metal hydroxide-based flame retardant conventionally used for this kind of flame-retardant polyolefin is used. Examples thereof include aluminum hydroxide and magnesium hydroxide. , Zirconium hydroxide,
Calcium hydroxide, barium hydroxide, and the like.
These may be used alone or in combination of two or more. In particular,
Among these, aluminum hydroxide, magnesium hydroxide and calcium hydroxide are preferred, and magnesium hydroxide is particularly preferred. The preferred particle size varies depending on the compound, but in the case of aluminum hydroxide, magnesium hydroxide, calcium hydroxide, etc., the average particle size is generally 1 to 20 μm, preferably 0.5 to 5.0 μm. The average particle size is a particle size measured by a laser diffraction scattering method. As described above, the amount of the metal hydroxide-based flame retardant is generally 10 to 7 with respect to 100 parts by weight of the polyolefin-based resin.
It is 0 parts by weight, preferably 20 to 60 parts by weight, particularly preferably 30 to 50 parts by weight. If the amount is less than 10 parts by weight, the composition may not exhibit sufficient flame retardancy, and if it is more than 70 parts by weight, the flexibility of the composition is impaired.

The swellable clay mineral is a clay mineral which can swell with water, and is, for example, one or two selected from smectite, vermiculite, kaolinite, halosite, mica, and layered silicate. These minerals are mentioned. Among these, smectite is particularly preferred. Due to its swelling property, the swellable clay mineral significantly improves the flame retarding action of the metal hydroxide-based flame retardant in a relatively small amount. Further, the average particle diameter is 0.001 to 1.000.
μm, and preferably 0.005 to 0.050 μm. The average particle size is determined by the Andreazen pipette method (JIS) utilizing the difference in sedimentation velocity when the particles are dispersed in water.
Z 8821).

The amount of the swellable clay mineral used is generally 2 parts per 100 parts by weight of the polyolefin resin as described above.
It is about 30 parts by weight, preferably 5 to 15 parts by weight. If the amount is less than 2 parts by weight, the composition will hardly exhibit sufficient flame retardancy, and if it is more than 30 parts by weight, the strength of the composition will be reduced and the flexibility will be impaired.

The above-mentioned metal hydroxide-based flame retardants include those having improved dispersibility in a polyolefin-based resin (the improved dispersibility is based on the flame retardancy, softness, tensile properties (strength, elongation), etc. of the resin composition). Surface treatment with a coupling agent or a fatty acid may be performed for the purpose of mixing the surface treated with a coupling agent and a surface treated with a fatty acid. You may use it.
As the coupling agent, an aminosilane-based coupling agent, an aminotitanate-based coupling agent, and the like are preferable.
As the fatty acid, those having 15 to 20 carbon atoms are preferable, and palmitic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, and the like are particularly preferable. These may be used alone or in combination of two or more. You may.

As the aminosilane-based coupling agent,
γ-aminopropyltriethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, γ-ureidopropyltriethoxysilane, γ-anilinopropyltrimethoxysilane, aminobenzenetriethoxysilane, N- 4,4'-methylenebisbenzeneamino-cyclohexanolethyltrimethoxysilane, N-4,4'-methylenebisbenzeneamino-2-
Hydroxypropyloxypropyltrimethoxysilane, N-aminobenzenemethylene-p-phenylene-γ
-Ureidopropyltrimethoxysilane, N-4,4 '
-Oxybisbenzeneamino-cyclohexanolethyltrimethoxysilane, N-4,4'-oxybisbenzeneamino-2-hydroxypropyloxypropyltrimethoxysilane, N-aminobenzeneoxy-p-phenylene-γ-ureidopropyltrimethoxysilane Methoxysilane,
N-4,4'-sulfonylbenzeneamino-cyclohexanolethyltrimethoxysilane, N-4,4'-sulfonylbenzeneamino-2-hydroxypropyloxypropyltrimethoxysilane, N-aminobenzenesulfonyl-p-phenylene-γ -Ureidopropyltrimethoxysilane, Np-phenylenediamino-cyclohexanolethyltrimethoxysilane, Np-phenylenediamino-2-hydroxypropyloxypropyltrimethoxysilane, Np-phenylenediamino-
γ-ureidopropyltrimethoxysilane and the like, and one or more of these are used.

As aminotitanate coupling agents, γ-aminopropyltriethoxytitanium, N-β-
(Aminoethyl) -γ-aminopropyltrimethoxytitanium, γ-ureidopropyltriethoxytitanium, γ-
Anilinopropyltrimethoxytitanium, aminobenzenetriethoxytitanium, N-4,4'-methylenebisbenzeneamino-cyclohexanolethyltrimethoxytitanium, N-4,4'-methylenebisbenzeneamino-2
-Hydroxypropyloxypropyltrimethoxytitanium, N-aminobenzenemethylene-p-phenylene-γ
-Ureidopropyltrimethoxytitanium, N-4,4 '
-Oxybisbenzeneamino-cyclohexanolethyltrimethoxytitanium, N-4,4'-oxybisbenzeneamino-2-hydroxypropyloxypropyltrimethoxytitanium, N-aminobenzeneoxy-p-phenylene-γ-ureidopropyltri Methoxy titanium,
N-4,4'-sulfonylbenzeneamino-cyclohexanolethyltrimethoxytitanium, N-4,4'-sulfonylbenzeneamino-2-hydroxypropyloxypropyltrimethoxytitanium, N-aminobenzenesulfonyl-p-phenylene-γ -Ureidopropyltrimethoxytitanium, Np-phenylenediamino-cyclohexanolethyltrimethoxytitanium, Np-phenylenediamino-2-hydroxypropyloxypropyltrimethoxytitanium, Np-phenylenediamino-
γ-ureidopropyltrimethoxytitanium and the like, and one or more of these are used.

The surface treatment method using a coupling agent or a fatty acid is not particularly limited, and a general method, for example, a method in which a metal hydroxide-based flame retardant is added to an alcohol solution of a coupling agent or a fatty acid and treated. A so-called slurry method in which drying is performed later, a dry method in which a coupling agent or a fatty acid is directly sprayed on the metal hydroxide powder, or the like is used. The treatment amount (adhesion amount) of the coupling agent or the fatty acid varies depending on the type of the coupling agent or the fatty acid, but is preferably about 0.002 to 5.000% by weight based on the metal hydroxide-based flame retardant, Especially preferably, it is 0.100-3,000 weight%.

The swellable clay mineral has an improved dispersibility in a polyolefin resin (the improved dispersibility is improved by improving the flame retardancy, flexibility, tensile properties (strength and elongation), etc. of the resin composition). Organic treatment, that is, a treatment for introducing an organic cation such as a quaternary ammonium salt between the layers of the mineral. The organic component of the organic cation is not particularly limited, but usually has 1 to 3 carbon atoms.
0 is an aliphatic (which may be linear or branched) or aromatic hydrocarbon group.

Since the organically treated swellable clay mineral contains a hydrocarbon group in the molecule, the dispersibility in the polyolefin resin is improved. Organic treatment of smectite is preferable because smectite can be introduced in a larger amount than other swelling clay minerals by organic treatment. Among the organically treated smectites, organically treated montmorillonite and / or organically treated hectorite are preferred. For the organic treatment of the swellable clay mineral, a slurry method, a dry method, or the like similar to the surface treatment of the metal hydroxide-based flame retardant described above is used. The processing amount, preferably from 1 to 50 by weight% with respect to swelling clay minerals, particularly preferably 10 to 20 wt%.

The flame-retardant polyolefin resin composition having a specific composition used in the present invention is a composition having a relatively small proportion of an inorganic substance (metal hydroxide flame retardant and swellable clay mineral) to the polyolefin resin. Therefore, the composition has excellent tensile properties (tensile strength and elongation) and a small specific gravity. That is, the tensile strength is 10 MPa or more,
The elongation is 350% or more, and the specific gravity is generally 1.1 to 1.2.
About. The tensile properties of such a composition provide more favorable results, especially in preventing twisting and durability of the cable during repeated movements of the elevator cable in a U-shaped bent state. Also, since the specific gravity of about 1.1 to 1.2 is much smaller than that of PVC (about 1.4),
The composition can be separated from PVC and recycled. In other words, in recent recycling of plastic materials, in order to separate and collect used plastics for each type of plastic, a method is used in which used plastics are put into uniformly flowing water and plastics are separated based on the difference in specific gravity of plastics. However, it can be separated and recovered from PVC. The tensile strength and elongation of the above composition were measured according to JIS C 300
5-18. Are values measured according to the tensile test of the sheath and the insulator.

In addition, the flame-retardant polyolefin-based resin composition may impair the desired flame retardancy and flexibility.
An appropriate amount of various auxiliary materials that do not include halogen atoms as constituent atoms may be blended within a range that does not cause a remarkable increase in specific gravity or a decrease in tensile properties. Such auxiliary materials include stabilizers, antioxidants, fillers, coloring agents, carbon black, crosslinking agents,
Lubricants, processability improvers, antistatic agents and the like.

The flame-retardant polyolefin-based resin composition comprises a polyolefin-based resin, a metal hydroxide-based flame retardant, a swelling clay mineral, and auxiliary materials to be blended if necessary. It is prepared by melt-kneading with a known kneading device such as a screw extruder.

The flame-retardant cable of the present invention comprises the flame-retardant polyolefin resin composition prepared by melt-kneading,
It is manufactured by molding by any molding method such as extrusion molding, injection molding, rotational molding, press molding and the like, covering the insulated conductor and forming a sheath.

In the case of manufacturing a product having a reinforcing wire, for example, an extruder in which a resin molding die (nipple) having a cable core feeding hole and a reinforcing wire feeding hole is inserted into a die is used. While feeding the cable core (and the reinforcing wire) forward (in the extrusion direction) through the feeding hole, at the same time, the molten kneaded material (resin composition) was inserted from the back between the nipple outer peripheral surface and the die inner peripheral hole. A sheath that covers the cable core and the reinforcing wire by supplying and extending around the cable core and the reinforcing wire fed out to the front opening end of the nipple, and being pushed out from the front opening end of the inner peripheral hole of the die in this state. Is molded.

Further, when manufacturing a cable in which not only the sheath but also the insulator of the insulated conductor is formed of the above flame-retardant polyolefin-based resin composition, when the insulated conductor is produced, for example, the conductor for the insulated conductor is extruded. While being fed into the machine, the melt-kneaded product of the flame-retardant polyolefin-based resin composition is continuously extruded to produce an insulated conductor in which an insulator made of the composition is formed on the outer periphery of the side surface of the conductor.

Although the flame-retardant cable of the present invention is suitable for an elevator cable as described above, it goes without saying that it can be applied to cables for various applications requiring flame retardancy and flexibility (flexibility). No.

[0041]

The present invention will be described more specifically with reference to the following examples and comparative examples, but the present invention is not limited to the following examples.

(Examples 1 to 8 and Comparative Examples 1 to 4)
2 (upper column), the materials shown in (upper column) were put into a Banbury mixer (manufactured by Toyo Seiki Seisaku-sho, Ltd.), melt-kneaded for 20 minutes, and then molded at 160 ° C. for 10 minutes by press molding, and the test sheets of Examples and Comparative Examples were obtained. (Test piece) was prepared, and the tensile modulus, tensile strength and elongation were measured. The specific gravity was calculated for each. The results are shown in Tables 1 and 2 (lower column)
Shown in

For each example and each comparative example, the materials shown in Tables 1 and 2 (upper column) were put into a Banbury mixer (manufactured by Toyo Seiki Seisaku-sho, Ltd.) at one time, and were melt-kneaded for 20 minutes. While feeding a copper wire (outer diameter 1.2 mm) obtained by twisting a soft copper wire having a wire diameter of 0.18 mm into the extruder,
Continuously extruded, 0.4mm thick on the outer periphery of the side of the copper conductor
Then, six insulated conductors having an outer diameter of 6.0 mm were formed by twisting six insulated conductors with a twisting machine around a polypropylene string having an outer diameter of 2.0 mm. Created. Then, an extrusion molding machine (a resin molding die (nipple) having a cable core feeding hole inside the die)
), While feeding the prepared cable core forward (extrusion direction) through the feeding hole, and at the same time, from the rear between the nipple outer peripheral surface and the die inner peripheral hole, from the rear, in the same manner as described above. The melt-kneaded material of the materials shown in Tables 1 and 2 melt-kneaded in is supplied to cover the periphery of the cable core fed to the front open end of the nipple, and in this state, extruded from the front open end of the inner peripheral hole of the die. Thus, a flat cable for an elevator cable having the structure shown in FIG. 1 was produced. In addition, the arrangement of the cable core is such that a partition having a width of 2.0 mm is provided between the second and third and the fourth and fifth of the six, and the thickness of the sheath is 1.8 m.
m. The cable dimensions are the cross-sectional dimensions (47 m
mx 9.7 mm), the total length is 100 m, and the approximate mass is 70
kg.

The free bending diameters of the cables of each of the examples and comparative examples prepared in this manner were measured by the following methods, and each of them was evaluated for its flame retardancy by a 60 ° inclined combustion test established in JIS C 3005. An evaluation was performed.
The results are shown in Tables 1 and 2 (lower column).

In Comparative Example 5, a test sheet (test piece) was prepared in the same manner as above using a PVC compound (commercially available) conventionally used as an insulating material for elevator cables. The elastic modulus, tensile strength, and elongation were measured, and a cable was further manufactured. The free bending diameter of the cable and the flame retardancy were evaluated by a 60 ° inclined combustion test. The results are shown in Table 2 (lower column).

[Free bending diameter of cable]
A sample (cable) having a length of 6 m is cut, and the sample is subjected to −5.
Under each temperature condition of ° C., + 20 ° C., and + 40 ° C., as shown in FIG. 3, one end is fixed, and the cables facing each other are suspended in a U-shape so as to be parallel to the length direction. The inner diameter (D) of the U-shaped part was measured.

[0047]

[Table 1]

[0048]

[Table 2]

LLDPE in Table 2 is a linear low density polyethylene. In addition, the cables of Examples 1 to 8 and Comparative Examples 1 to 5 were all 60 ° in accordance with JIS C 3005.
Since the inclined combustion test was passed, the results are shown in Tables 1 and 2.
Is not shown.

As can be seen from Tables 1 and 2, Examples 1 to 8
The composition (test piece) for the insulator of the sheath and the insulated conductor melt-kneaded in Example 1 had a high oxygen index, excellent flame retardancy, and a sufficiently low tensile modulus. Further, the specific gravity is considerably smaller than that of the PVC compound of Comparative Example 5 (separation and collection from PVC is possible). A cable actually using these as an insulator of a sheath and an insulated conductor is a 60 ° cable stipulated in JISC 3005.
It passed the inclined combustion test, and its free bending diameter was a value sufficiently close to that of the cable of Comparative Example 5 using PVC compound for the insulator of the sheath and the insulated conductor, showing good flexibility (flexibility). Was. From this, the cables of Examples 1 to 8 are particularly suitable for applications requiring not only flame retardancy but also flexibility (flexibility) such as elevator cables.
It turns out that it can be used suitably as a substitute of a VC cable.

[0051]

As is apparent from the above description, according to the present invention, there is provided a flame-retardant material having both good flame retardancy and flexibility (flexibility) without fear of generating toxic gas during incineration of waste. Cable can be obtained. The flame-retardant cable of the present invention is an alternative to a cable using PVC as an insulating material (especially a cable that is required to have flexibility (flexibility) as well as flame retardancy). It can also be used for elevator cables, which have been difficult to apply when the insulating material is formed from the conductive polyolefin-based resin composition.

[Brief description of the drawings]

FIG. 1 is a schematic perspective sectional view of an example of a flame-retardant cable according to the present invention.

FIG. 2 is a schematic perspective sectional view of another example of the flame-retardant cable of the present invention.

FIG. 3 is a diagram illustrating a method for measuring a free bending diameter of a cable.

FIG. 4 is a vertical sectional view of a hoistway showing an attached state of an elevator cable.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Insulated conducting wire 2 Cable core 3 Sheath 4 Core material 5 Flat cable

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01B 7/04 H01B 7/34 B (72) Inventor Masaka Nakai 8-8 Nishinocho, Higashimukaijima, Amagasaki City, Hyogo Prefecture Mitsubishi F term (reference) in Denki Kogyo Co., Ltd. 4J002 BB031 BB071 BB111 BB161 DE076 DE086 DE096 DE146 DJ007 DJ037 DJ057 FD136 5G311 AA03 AB02 AC06 AD01 5G315 CA03 CB02 CB06 CD02 CD11 CD14 CD17

Claims (7)

[Claims] 1. A flat cable which has a plurality of cable cores each comprising one insulated conductor or an aggregate of a plurality of insulated conductors, and the plurality of cable cores are arranged in parallel, covered with a sheath and integrated. The sheath or the insulator between the sheath and the insulated conductor is made of a polyolefin resin 10
A flame retardant comprising a flame-retardant polyolefin resin composition containing 10 to 70 parts by weight of a metal hydroxide-based flame retardant and 2 to 30 parts by weight of a swellable clay mineral per 0 parts by weight. Cable. 2. The flame-retardant cable according to claim 1, wherein the polyolefin resin is an ethylene-ethyl acrylate copolymer. 3. The flame-retardant cable according to claim 1, wherein the flame-retardant polyolefin resin composition has an oxygen index of 22 or more and a tensile modulus of 30 MPa or less. 4. The flame-retardant cable according to claim 1, wherein the specific gravity of the flame-retardant polyolefin resin composition is 1.1 to 1.3. 5. The flame-retardant cable according to claim 1, wherein the flame-retardant polyolefin resin composition has a tensile strength of 10 MPa or more and an elongation of 350% or more. 6. The flame-retardant cable according to claim 1, wherein the cable core is formed by twisting a plurality of insulated conductors. 7. The method according to claim 1, which is for an elevator cable.
7. The flame-retardant cable according to any one of 6.