JP6860833B2 - Flame-retardant insulated wires and flame-retardant cables - Google Patents

Description

The present invention relates to a flame-retardant insulated electric wire and a flame-retardant cable.

The insulated wire has a conductor and an insulating layer as a coating material provided around the conductor. Further, the cable includes, for example, a stranded wire obtained by twisting the above-mentioned electric wires and a sheath provided around the stranded wire. The insulating layer of the insulated wire and the sheath of the cable are made of an electrically insulating material mainly made of rubber or resin. Such insulated wires and cables have different required characteristics depending on the application. For example, electric wires for electronic devices or railway vehicles are required to have high flame retardancy, and specifically, they are required to pass the vertical combustion test VW-1 specified in the flame retardancy standard UL1581.

As an example of such an electric wire, Patent Document 1 describes a flame-retardant insulated electric wire including a conductor and an insulating layer coated around the conductor, wherein the insulating layer is a resin component mainly composed of an ethylene-based polymer. A flame-retardant insulated electric wire made of a resin composition to which a metal hydroxide is added is described.

Japanese Unexamined Patent Publication No. 2015-2062

However, according to the study of the present inventor, it has been confirmed that when the insulating layer of the flame-retardant insulated wire is formed, the fluidity of the resin composition may decrease and the extrusion processability may be impaired.

The present invention has been made in view of such problems, and an object of the present invention is to provide a flame-retardant insulated electric wire and a flame-retardant cable having flame retardancy and extrusion processability.

A brief description of typical inventions disclosed in the present application is as follows.

[1] The flame-retardant insulated wire has a conductor and an insulating layer coated around the conductor, and the insulating layer includes an ethylene-based polymer, a metal hydroxide, and a plurality of phenols in the molecule. It comprises a flame-retardant resin composition containing a compound having a sex hydroxyl group and no carboxyl group. The flame-retardant resin composition contains 100 parts by mass or more and 180 parts by mass or less of the metal hydroxide with respect to 100 parts by mass of the ethylene-based polymer, and the flame-retardant resin composition is the ethylene-based polymer 100. It contains 2 parts by mass or more of the compound with respect to parts by mass.

[2] In the flame-retardant insulated wire according to [1], the compound is an ester derivative of gallic acid.

[3] In the flame-retardant insulated wire according to [1], the compound is at least one selected from the group consisting of methyl gallate, propyl gallate, 2,3,4-trihydroxybenzophenone, and bisphenol A. Two compounds.

[4] The flame-retardant cable has a core including an insulated wire composed of a conductor and an insulating layer coated around the conductor, and a sheath provided around the core, and the sheath is made of ethylene. It comprises a flame-retardant resin composition containing a based polymer, a metal hydroxide, and a compound having a plurality of phenolic hydroxyl groups in the molecule and having no carboxyl group. The flame-retardant resin composition contains 100 parts by mass or more and 180 parts by mass or less of the metal hydroxide with respect to 100 parts by mass of the ethylene-based polymer, and the flame-retardant resin composition is the ethylene-based polymer 100. It contains 2 parts by mass or more of the compound with respect to parts by mass.

[5] In the flame-retardant cable according to [4], the compound is an ester derivative of gallic acid.

[6] In the flame-retardant cable according to [4], the compound is at least one selected from the group consisting of methyl gallate, propyl gallate, 2,3,4-trihydroxybenzophenone, and bisphenol A. It is a compound.

According to the present invention, it is possible to provide a flame-retardant insulated electric wire and a flame-retardant cable having flame retardancy and extrusion processability.

It is sectional drawing which shows the structure of the electric wire of one Embodiment. It is sectional drawing which shows the structure of the electric wire of 2nd Embodiment. It is sectional drawing which shows the structure of the cable of one Embodiment.

(Consideration)
First, before explaining the embodiment, the matters examined by the present inventor will be described.

Conventionally, in order to improve the flame retardancy of a resin composition, it is known to add a metal hydroxide such as magnesium hydroxide, which is a flame retardant, to the resin composition. Therefore, as an example of such an electric wire, the present inventor has found that in a flame-retardant insulated electric wire including a conductor and an insulating layer coated around the conductor, the insulating layer is mainly composed of (A) ethylene-based polymer. A flame-retardant insulated wire made of a resin composition to which (B) a metal hydroxide was added to the resin component to be used was examined (hereinafter, referred to as a flame-retardant insulated wire in the study example).

As described above, the flame-retardant insulated wire of the study example is required to have flame retardancy that passes the vertical combustion test VW-1 specified in the flame-retardant standard UL1581. As shown in Examples described later, the present inventor has prepared (A) metal hydroxide with respect to 100 parts by mass of a resin component mainly composed of an ethylene polymer in the resin composition constituting the insulating layer. It was confirmed that VW-1 was not passed unless 220 parts by mass or more of magnesium hydroxide (B1), which is a kind of product, was added. Here, the flame-retardant action of the metal hydroxide is due to the suppression of thermal decomposition of the resin utilizing the endothermic reaction. If the combustible gas generated by the thermal decomposition of the resin cannot be completely suppressed, the reaction between the combustible gas and oxygen will continue, and VW-1 cannot be passed. Therefore, it is considered necessary to mix the metal hydroxide in a relatively high ratio with respect to the resin component so that the thermal decomposition of the resin can be completely suppressed.

On the other hand, according to the present inventor, as shown in Examples described later, in the flame-retardant insulated wire of the study example, the resin composition constituting the insulating layer is (A) a resin component 100 mainly composed of an ethylene polymer. When 165 parts by mass or more of (B1) magnesium hydroxide, which is a kind of (B) metal hydroxide, is added to parts by mass, the material components in the resin composition collide with each other, rub against each other, adhere to each other, and adhere to each other. It was confirmed that the resin composition aggregated to reduce the fluidity of the resin composition and impair the extrudability. That is, when the fluidity of the resin composition is lowered, it is necessary to reduce the extrusion speed of the extruder when the insulating layer of the electric wire is extruded and coated, which causes a problem that the manufacturing efficiency of the electric wire is lowered.

That is, in the resin composition constituting the insulating layer of the insulated wire, if the ratio of (B) metal hydroxide to the resin component mainly composed of (A) ethylene polymer is too low, flame retardancy is maintained. On the other hand, if the ratio of (B) metal hydroxide is too high, the problem of extrudability is impaired.

It should be noted that such a problem occurs not only in the insulating layer of the insulated wire but also in the sheath of the cable formed by the extrusion coating.

From the above, it is desired to provide a flame-retardant insulated wire and a flame-retardant cable having flame-retardant and extrudable properties by devising the configuration of the flame-retardant insulated wire and the flame-retardant cable. ..

(Embodiment)
<Construction and manufacturing method of flame-retardant insulated wire>
1 and 2 are cross-sectional views showing a flame-retardant insulated electric wire according to an embodiment of the present invention. As shown in FIG. 1, the flame-retardant insulated wire 10 according to the first embodiment has a conductor 1 and an insulating layer 2 coated around the conductor 1. The insulating layer 2 is made of a flame-retardant resin composition according to an embodiment of the present invention, which will be described in detail below. The thickness of the insulating layer 2 is not particularly limited, but is preferably 0.15 to 2 mm.

As the conductor 1, in addition to commonly used metal wires such as copper wire and copper alloy wire, aluminum wire, gold wire, silver wire, optical fiber and the like can be used. Further, as the conductor 1, a conductor having metal plating such as tin or nickel around the metal wire may be used. Further, as the conductor 1, a stranded wire conductor obtained by twisting metal wires can also be used.

Further, a separator 6 made of, for example, polyester tape can be provided between the conductor 1 and the insulating layer 2. When a stranded conductor is used as the conductor 1 by providing the separator 6, the flame-retardant resin composition is introduced into the conductor 1 when the flame-retardant resin composition is extruded, that is, when the insulating layer 2 is formed. It is possible to prevent sneaking in.

The flame-retardant insulated wire 10 of the present embodiment is manufactured as follows, for example. First, a material containing (A) an ethylene polymer, (B) a metal hydroxide, and (C) a compound having a plurality of phenolic hydroxyl groups and no carboxyl group in the molecule is melt-kneaded and kneaded. Obtain the flame-retardant resin composition of the embodiment.

After that, the conductor 1 is prepared, and the flame-retardant resin composition of the present embodiment is extruded by an extrusion molding machine so as to cover the periphery of the conductor 1 (separator 6) to obtain an insulating layer 2 having a predetermined thickness. Form. By doing so, the flame-retardant insulated wire 10 can be manufactured.

The kneading device for producing the flame-retardant resin composition of the present embodiment is known as, for example, a known kneading machine such as a batch type kneader such as a Banbury mixer or a pressurized kneader, or a continuous kneader such as a twin-screw extruder. The device can be adopted.

Further, in the present embodiment, after the flame-retardant insulated wire 10 is manufactured, the flame-retardant resin composition constituting the insulating layer 2 is crosslinked by, for example, an electron beam cross-linking method or a chemical cross-linking method. In the flame-retardant insulated wire 10 of the present embodiment, it is not essential that such cross-linking is performed, but since the cross-linking improves the heat resistance of the flame-retardant resin composition, such cross-linking is performed. It is preferable that it is.

When the electron beam cross-linking method is used, the flame-retardant resin composition is formed as the insulating layer 2 of the flame-retardant insulated wire 10, and then cross-linked by irradiating an electron beam of, for example, 1 to 30 Mrad. When the chemical cross-linking method is used, a cross-linking agent is added to the flame-retardant resin composition in advance, and this flame-retardant resin composition is molded as the insulating layer 2 of the flame-retardant insulated wire 10 and then heat-treated. To bridge. In the examples described later, the electron beam cross-linking method is used.

Further, as shown in FIG. 2, the flame-retardant insulated wire 20 according to the second embodiment is provided around the conductor 1, the insulating inner layer 2a provided around the conductor 1, and the insulating inner layer 2a. It has an insulating outer layer 2b. The flame-retardant insulated wire 20 of the second embodiment is different from the flame-retardant insulated wire 10 of the first embodiment in that the insulating layer is composed of the insulating inner layer 2a and the insulating outer layer 2b. The insulating outer layer 2b is made of the flame-retardant resin composition of the present embodiment. The insulating inner layer 2a is made of an insulating resin such as polyethylene.

The flame-retardant resin composition used in the present embodiment is not limited to the electric wires produced in the examples, and can be applied to all uses and sizes, for in-panel wiring, for vehicles, for automobiles, and for in-equipment wiring. , Can be used for the insulating layer of each electric wire for electric power.

<Composition of flame-retardant cable>
FIG. 3 is a cross-sectional view showing a flame-retardant cable 30 according to an embodiment of the present invention. As shown in FIG. 3, the flame-retardant cable 30 according to the present embodiment is provided around the three-core stranded wire obtained by twisting three of the above-mentioned flame-retardant insulated wires 10 and the three-core stranded wire. It is provided with a core including the interposition 5 and a sheath 4 provided around the core. The sheath 4 is made of the above-mentioned flame-retardant resin composition.

The flame-retardant cable 30 of the present embodiment is manufactured as follows, for example. First, three flame-retardant insulated electric wires 10 are manufactured by the method described above. After that, the flame-retardant insulated wire 10 is twisted together with the interposition 5 such as sufu thread, kraft paper, paper tape, and jute, and then (A) ethylene polymer and (B) metal hydroxide are applied so as to cover them. And (C) a flame-retardant resin composition kneaded with a material containing a compound having a plurality of phenolic hydroxyl groups and no carboxyl group in the molecule is extruded. Then, for example, the flame-retardant resin composition is irradiated with an electron beam to crosslink the (A) ethylene-based polymer in the flame-retardant resin composition to form a sheath 4 having a predetermined thickness. By doing so, the flame-retardant cable 30 of the present embodiment can be manufactured.

The case where the cable 11 of the present embodiment has a three-core stranded wire obtained by twisting three flame-retardant insulated wires 10 as a core wire has been described as an example, but the core wire may be a single core (one) or three. It may be a multi-core stranded wire other than the core. Further, there may be no interposition 5 between the flame-retardant insulated wire 10 and the sheath 4, and conversely, another insulating layer (sheath) may be provided between the flame-retardant insulated wire 10 and the sheath 4. ) Is formed, and a multi-layer sheath structure can also be adopted. Further, a shield layer made of a braided structure of a metal tape or a copper wire may be provided between the flame-retardant insulated wire 10 and the sheath 4.

Further, the flame-retardant cable 30 of the present embodiment has been described by taking the case where the above-mentioned flame-retardant insulated electric wire 10 is used as an example, but the present invention is not limited to this, and an electric wire using a general-purpose material such as polyethylene is used. You can also do it.

<Structure of flame-retardant resin composition>
Hereinafter, the flame-retardant resin composition of the present embodiment will be described in detail. The flame-retardant resin composition according to the present embodiment has (A) an ethylene polymer, (B) a metal hydroxide, and (C) a plurality of phenolic hydroxyl groups in the molecule and has a carboxyl group. Contains compounds that do not. Hereinafter, in the present embodiment, the ethylene polymer (A) constituting the flame-retardant resin composition may be described as a base polymer. Further, when (B) a metal hydroxide constituting the flame-retardant resin composition and (C) a compound having a plurality of phenolic hydroxyl groups in the molecule and not having a carboxyl group are collectively described as a flame retardant. There is.

Examples of the (A) ethylene-based polymer of the present embodiment include an ethylene-vinyl acetate copolymer, an ethylene-acrylic acid ester copolymer, and an ethylene-α-olefin copolymer. Since it may be buried in the soil depending on the type of cable, a polymer having no biodegradability is preferable, and as the (A) ethylene-based polymer, an ethylene-vinyl acetate copolymer is preferable.

Examples of the (B) metal hydroxide of the present embodiment include magnesium hydroxide, aluminum hydroxide, calcium hydroxide, hard clay, hydrotalcite, and the like, among which (B1) magnesium hydroxide or (B2). Aluminum hydroxide is preferred. (B1) Magnesium hydroxide includes, for example, untreated surface (natural magnesium hydroxide or synthetic magnesium hydroxide obtained by crushing brucite ore), silane coupling agent, phosphoric acid ester, or stearic acid. Examples thereof include those surface-treated with fatty acids such as oleic acid. In particular, as (B1) magnesium hydroxide, it is preferable to use magnesium hydroxide that has been surface-treated with a silane coupling agent. This is because magnesium hydroxide surface-treated with a silane coupling agent has a high affinity with a polymer, and thus the tensile properties of the flame-retardant resin composition using the magnesium hydroxide are improved. The metal hydroxide contains 100 parts by mass or more and 180 parts by mass or less with respect to 100 parts by mass of the ethylene polymer. As shown in Examples described later, when (B1) magnesium hydroxide is used, it is preferably 100 parts by mass or more and 160 parts by mass or less with respect to 100 parts by mass of the base polymer. (B1) If the amount of magnesium hydroxide is less than 100 parts by mass with respect to 100 parts by mass of the base polymer, the flame retardancy required for the insulating layer of the electric wire cannot be obtained, and if it exceeds 160 parts by mass, the material components collide with each other. -Friction, adhesion, and aggregation reduce the fluidity, and the extrusion processability when forming the insulating layer of the electric wire is impaired. Examples of (B2) aluminum hydroxide include those having no surface treatment and those having a surface treated with a silane coupling agent, a phosphoric acid ester, or a fatty acid such as stearic acid or oleic acid. (B2) When aluminum hydroxide is used, it is preferably 100 parts by mass or more and 180 parts by mass or less with respect to 100 parts by mass of the base polymer.

Examples of the compound (C) of the present embodiment having a plurality of phenolic hydroxyl groups and no carboxyl group include ester derivatives of gallic acid ((C1) methyl gallate, (C2) propyl gallate). Etc.), pyrogallol, catechol, gallotannin, (C3) 2,3,4-trihydroxybenzophenone, (C4) bisphenol A and the like.

In addition, in (C) a compound having a plurality of phenolic hydroxyl groups in the molecule and not having a carboxyl group, only one phenolic hydroxyl group is defined as "having a plurality of phenolic hydroxyl groups" in the molecule. This is because the present inventor has confirmed that the radical trapping effect of the phenolic hydroxyl group is not sufficiently exhibited in the case of a compound that does not have it. The radical trap effect is an effect in which the flame retardant reacts with radicals in the combustion product of the gas phase to stabilize the flame retardant and suppress the reaction with oxygen.

Further, in the compound (C) having a plurality of phenolic hydroxyl groups in the molecule and not having a carboxyl group, "having no carboxyl group" is defined as having a carboxyl group as shown in a comparative example described later. This is because when the compound is added, the fluidity of the resin composition decreases due to the interaction with (B) the metal hydroxide, and the processability evaluation at the time of extrusion fails. Further, due to the strong polarity of the carboxyl group, gallic acid has a melting point of 280 ° C. or higher, does not melt at a normal processing temperature, and exists as agglomerates in the resin composition, so that it tends to be a starting point of mechanical destruction. Therefore, propyl gallate (C3) 2,3,4-trihydroxybenzophenone and (C4) bisphenol A, which have a low melting point, for example, a melting point of 200 ° C. or lower, are suitable.

Further, as a compound having a plurality of phenolic hydroxyl groups in the molecule and not having a carboxyl group, ester derivatives of gallic acid ((C1) methyl gallate, (C2) propyl gallate, etc.), pyrogallol, catechol, etc. , Gallotannin, (C3) 2,3,4-trihydroxybenzophenone, (C4) bisphenol A, and the like may be selected and used in combination.

As shown in Examples described later, the amount of the compound (C) having a plurality of phenolic hydroxyl groups in the molecule and having no carboxyl group is 2 parts by mass or more with respect to 100 parts by mass of the base polymer. Is preferable. (C) When the amount of the compound having a plurality of phenolic hydroxyl groups and no carboxyl group in the molecule is less than 2 parts by mass with respect to 100 parts by mass of the base polymer, the flame retardancy required for the insulating layer of the electric wire is obtained. This is because it is necessary to add a large amount of (B) metal hydroxide in order to obtain it. (C) The upper limit of the content of the compound having a plurality of phenolic hydroxyl groups and no carboxyl group in the molecule is not particularly limited, but is 40 parts by mass or less, more preferably 20 parts by mass. It is as follows.

Further, the total amount of the (B) metal hydroxide and (C) the compound having a plurality of phenolic hydroxyl groups and no carboxyl group in the molecule, which is the flame retardant of the present embodiment, is 100 parts by mass of the base polymer. On the other hand, it is preferably 100 parts by mass or more and less than 220 parts by mass. If the total amount of the flame retardants is less than 100 parts by mass with respect to 100 parts by mass of the base polymer, flame retardancy that passes the VW-1 test cannot be obtained, and if it is 220 parts by mass or more, the extrusion processability is lowered. , Workability evaluation may fail.

In addition to the above materials, the flame retardant resin composition of the present embodiment includes other flame retardants, flame retardants, cross-linking agents, cross-linking aids, processing aids, coupling agents, etc., if necessary. It may contain a surface treatment agent, a colorant, a lubricant, an antioxidant, an ozone deterioration inhibitor, an ultraviolet absorber, a light stabilizer, a metal chelator, a softener, a plasticizer, etc. within a range that does not affect the characteristics. ..

The flame-retardant resin composition of the present embodiment is applicable to all uses and sizes including cables, not limited to the electric wires produced in the examples described later, and is used for railway vehicles, automobiles, and in-panel wiring. It can be used for the insulating layer of each electric wire for wiring in equipment and for electric power, and for the sheath of each cable.

<Characteristics and effects of this embodiment>
One of the features of the flame-retardant insulated wires 10 and 20 according to the present embodiment shown in FIGS. 1 and 2 is that the conductor 1 and the insulating layer 2 (insulating inner layer 2a) coated around the conductor 1 are provided. The insulating layer 2 (insulating outer layer 2b) has (A) an ethylene-based polymer, (B) a metal hydroxide, and (C) a compound having a plurality of phenolic hydroxyl groups in the molecule and no carboxyl group. It is composed of a flame-retardant resin composition containing and.

Further, one of the features of the flame-retardant cable 30 according to the present embodiment shown in FIG. 3 is a sheath 4 provided around the flame-retardant insulated electric wire 10, and the sheath 4 is the flame-retardant resin. It is composed of a composition.

In the present embodiment, by adopting such a configuration, it is possible to provide a flame-retardant insulated electric wire and a flame-retardant cable having flame retardancy and extrusion processability. The reason for this will be described in detail below.

As described above, in the resin composition constituting the insulating layer of the flame-retardant insulated wire of the study example, the present inventor has (A) a resin component mainly composed of an ethylene polymer and (B) metallic water. It has been confirmed that if the ratio of the oxide is too low, the flame retardancy cannot be maintained, while if the ratio of the (B) metal hydroxide is too high, the extrusion processability is impaired.

Therefore, the present inventor has provided the insulating layer of the flame-retardant insulated wire according to the present embodiment with (A) an ethylene polymer, (B) a metal hydroxide, and (C) a plurality of phenolic hydroxyl groups in the molecule. It is composed of a flame-retardant resin composition containing a compound having and having no carboxyl group. As described above, by adding (C) a compound having a plurality of phenolic hydroxyl groups in the molecule and not having a carboxyl group as a flame retardant to the flame-retardant resin composition, the (A) ethylene-based polymer can be treated. (B) The ratio of the metal hydroxide can be lowered, and the extrusion processability of the flame retardant resin composition at the time of forming the coating layer of the electric wire can be improved. Similarly, the extrusion processability of the flame-retardant resin composition at the time of forming the sheath of the cable can be improved.

Then, by adding (C) a compound having a plurality of phenolic hydroxyl groups in the molecule and not having a carboxyl group as a flame retardant to the flame-retardant resin composition, (A) with respect to the ethylene-based polymer (B). ) Even when the ratio of the metal hydroxide is lowered, the flame retardancy of the flame-retardant insulated wire having the insulating layer made of the flame-retardant resin composition can be improved. Similarly, the flame retardancy of the flame-retardant cable including the sheath made of the flame-retardant resin composition can be improved.

As described above, the flame-retardant action of the metal hydroxide (B) is due to the suppression of thermal decomposition of the resin by utilizing the endothermic reaction. The flame-retardant action of the compound (C) having a plurality of phenolic hydroxyl groups in the molecule and not having a carboxyl group is due to the radical trapping effect. As described above, in the flame-retardant insulated electric wire and the flame-retardant cable of the present embodiment, since these flame retardants having different flame-retardant actions are used in combination, these flame retardants are produced by the synergistic effect. The flame retardancy can be further improved as compared with the case of using it alone.

Further, (C) a compound having a plurality of phenolic hydroxyl groups in the molecule and not having a carboxyl group has a radical trapping effect similar to that of a halide, and therefore, a halogen is added to the resin composition in order to exhibit flame retardancy. There is no need to add compounds. Therefore, according to the flame-retardant resin composition of the present embodiment, non-halogen flame-retardant flame-retardant that can prevent the generation of toxic gas at the time of fire and secondary disasters and does not cause any problem even if incinerated at the time of disposal Sexually insulated wires and non-halogen flame retardant cables can be provided.

(Example)
Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

<Outline of Examples and Comparative Examples>
Hereinafter, the flame-retardant insulated wires of Examples 1 to 10 and the insulated wires of Comparative Examples 1 to 6 will be described. The flame-retardant insulated wires of Examples 1 to 10 correspond to the flame-retardant insulated wires 10 shown in FIG. That is, the insulating layer 2 of the flame-retardant insulated wire 10 is made of the flame-retardant resin composition of the present embodiment. The shape of the insulated wire of Comparative Examples 1 to 6 is the same as that of the flame-retardant insulated wire 10 shown in FIG. 1, but the insulating layer 2 is different from the flame-retardant resin composition of the present embodiment. It consists of resin compositions having different compositions. The compositions of the flame-retardant resin compositions of Examples 1 to 10 and Comparative Examples 1 to 6 are shown in Table 1.

Table 1 shows examples and comparative examples in which an ethylene-vinyl acetate copolymer (EV170, manufactured by Mitsui DuPont Polychemical Co., Ltd.) was used as the (A) ethylene-based polymer. Similar results are obtained when other (A) ethylene-based polymers or a combination of a plurality of types (A) ethylene-based polymers are used. Further, as (B) metal hydroxide, (B1) silane-treated magnesium hydroxide (Magnes (registered trademark) S4, manufactured by Konoshima Chemical Co., Ltd.) or (B2) fatty acid-treated aluminum hydroxide (BF-013S (Nippon Light Metal)) )) Was used. Further, as (C1) methyl gallate, (C2) propyl gallate, (C3) 2,3,4-trihydroxybenzophenone and (C5) gallate, those manufactured by Tokyo Chemical Industry Co., Ltd. were used.

The method for manufacturing the flame-retardant insulated electric wire of Examples 1 to 10 is as follows. First, each of the materials of Examples 1 to 10 shown in Table 1 is dry-blended at room temperature, and the mixed materials are melt-kneaded with a pressure kneader at a take-out temperature of 150 ° C. to produce a flame-retardant resin composition. did. After that, an insulating layer made of a flame-retardant resin composition having a coating thickness of 0.41 mm was formed around a 22 AWG copper stranded wire using a Labo Plast Mill 20 mm single-screw extruder manufactured by Toyo Seiki, which is an extrusion coating device for manufacturing electric wires. By forming, an electric wire was produced (cylinder temperature 160 ° C., electric wire take-up speed 4.0 m / min). By performing an electron beam cross-linking treatment (6Mrad) on this electric wire, the flame-retardant resin composition constituting the insulating layer was cross-linked to produce the flame-retardant insulated electric wires of Examples 1 to 10. The method for manufacturing the insulated wire of Comparative Examples 1 to 6 is the same as that of the flame-retardant insulated wire of Examples 1 to 10, and will be omitted.

<Evaluation method of Examples and Comparative Examples>
(1) Workability evaluation For workability evaluation, the torque of the extruder at the time of forming the insulating layer of the electric wire is measured, and the one with this torque of 50 Nm or less is passed, and the one with this torque exceeding 50 Nm is not accepted. It was passed.

(2) Flame-retardant evaluation Regarding flame-retardant evaluation, the vertical combustion test VW-1 specified in the flame-retardant standard UL1581 was performed on the manufactured flame-retardant insulated wire, and it was judged whether it passed or failed. ..

As another index for evaluating flame retardancy, the oxygen index defined by JIS K 7201-2 was also measured. However, the flame retardancy evaluation was performed based on the result of the vertical combustion test VW-1.

For Examples 4 to 7, Comparative Example 4 and Comparative Example 5, the low temperature characteristics were evaluated as a reference test. A copper stranded wire was extracted from the produced flame-retardant insulated wire, and a tensile test was performed on the insulator at −40 ° C. by a method conforming to JIS C 3005 using a tensile tester with a low temperature bath. The sample had a tube shape and was left in a low temperature bath for 2 hours, and then a tensile test was performed at a speed of 25 mm / min. Those with an elongation of 30% or more were accepted, and those with an elongation of less than 30% were rejected.

<Details of Examples 1 to 10 and evaluation results>
As shown in Table 1, the flame-retardant resin compositions constituting the insulating layer of the flame-retardant insulated wires of Examples 1 to 10 include (A) ethylene-based polymer and (B) metallic water as the materials thereof. It contains an oxide and (C) a compound having a plurality of phenolic hydroxyl groups in the molecule and having no carboxyl group.

The flame-retardant resin compositions of Examples 1 and 3 use (C1) methyl gallate as a compound having a plurality of phenolic hydroxyl groups in the molecule and no carboxyl group.

The flame-retardant resin compositions of Examples 2, 4, 6, and 8 to 10 are (C) compounds having a plurality of phenolic hydroxyl groups in the molecule and no carboxyl group. , (C2) propyl gallate is used.

In the flame-retardant resin composition of Example 5, (C4) bisphenol A is used as the compound (C) having a plurality of phenolic hydroxyl groups in the molecule and not having a carboxyl group.

The flame-retardant resin composition of Example 7 uses (C3) 2,3,4-trihydroxybenzophenone as a compound (C) having a plurality of phenolic hydroxyl groups in the molecule and no carboxyl group. There is.

The flame-retardant resin compositions of Examples 1 and 2 have (B1) 125 parts by mass of magnesium hydroxide with respect to 100 parts by mass of (A) ethylene-based polymer, and (C) a plurality of flame-retardant resin compositions in the molecule. The compound having a phenolic hydroxyl group and no carboxyl group is 15 parts by mass.

On the other hand, in the flame-retardant resin compositions of Examples 3 and 4, 100 parts by mass of (B1) magnesium hydroxide was added to 100 parts by mass of (A) ethylene-based polymer, and (C) intramolecularly contained. The amount of the compound having a plurality of phenolic hydroxyl groups and no carboxyl group is 30 parts by mass. Therefore, in Examples 3 and 4, the compounding ratios of (B1) magnesium hydroxide and (C) a compound having a plurality of phenolic hydroxyl groups in the molecule and no carboxyl group are the blending ratios of Examples 1 and 2. Is different from.

Further, in the flame-retardant resin composition of Example 5, (A) 100 parts by mass of the ethylene polymer, (B1) magnesium hydroxide is 130 parts by mass, and (C) a plurality of phenolic compounds in the molecule. The compound having a hydroxyl group and no carboxyl group is 20 parts by mass.

Further, in the flame-retardant resin composition of Example 6, (A) 100 parts by mass of the ethylene polymer, (B1) magnesium hydroxide is 130 parts by mass, and (C) a plurality of phenolic compounds in the molecule. The compound having a hydroxyl group and no carboxyl group is 2 parts by mass.

The flame-retardant resin composition of Example 7 has (A) 160 parts by mass of magnesium hydroxide (B1) with respect to 100 parts by mass of an ethylene polymer, and (C) has a plurality of phenolic hydroxyl groups in the molecule. However, the amount of the compound having no carboxyl group is 15 parts by mass.

The flame-retardant resin composition of Example 8 has (A) 100 parts by mass of (B2) aluminum hydroxide with respect to 100 parts by mass of an ethylene polymer, and (C) has a plurality of phenolic hydroxyl groups in the molecule. However, the amount of the compound having no carboxyl group is 15 parts by mass.

The flame-retardant resin composition of Example 9 has (A) 130 parts by mass of (B2) aluminum hydroxide with respect to 100 parts by mass of an ethylene polymer, and (C) has a plurality of phenolic hydroxyl groups in the molecule. However, the amount of the compound having no carboxyl group is 15 parts by mass.

The flame-retardant resin composition of Example 10 has (A) 180 parts by mass of (B2) aluminum hydroxide with respect to 100 parts by mass of an ethylene polymer, and (C) has a plurality of phenolic hydroxyl groups in the molecule. However, the amount of the compound having no carboxyl group is 30 parts by mass.

As shown in Table 1, in Examples 1 to 10, both (1) processability evaluation and (2) flame retardancy evaluation passed regardless of the difference in the type of material and the compounding ratio of each material. Met.

<Details and evaluation results of Comparative Examples 1 to 6>
Comparative Examples 1 to 6 shown in Table 2 are obtained by changing the types of materials used in Examples 1 to 10 and the blending ratio of each material.

As shown in Table 2, the resin compositions of Comparative Examples 1 to 3 contain (A) ethylene-based polymer and (B) magnesium hydroxide as the materials thereof, and the resin compositions of Examples 1 to 3 contain (A) ethylene-based polymer and (B) magnesium hydroxide. Unlike No. 10, (C) does not contain a compound having a plurality of phenolic hydroxyl groups and no carboxyl group in the molecule.

The resin compositions of Comparative Examples 4 and 5 are composed of (A) ethylene polymer, (B1) magnesium hydroxide, and a compound having a plurality of phenolic hydroxyl groups in the molecule but also having a carboxyl group. Contains some (C5) gallic acid.

The resin composition of Comparative Example 6 contains (A) an ethylene polymer, (B1) magnesium hydroxide, and (C1) methyl gallate as its materials, and in this respect, the resin compositions of Examples 1 and 3 It is the same as the flame-retardant resin composition. However, Comparative Example 6 is different from Example 1 in that (B1) magnesium hydroxide is 80 parts by mass with respect to 100 parts by mass of (A) ethylene-based polymer.

As shown in Table 2, in Comparative Example 1, (1) workability evaluation and (2) flame retardancy evaluation were unacceptable.

Further, in Comparative Examples 2 to 5, (2) the flame retardancy evaluation was passed, while (1) the workability evaluation was unacceptable.

Further, in Comparative Example 6, (1) the workability evaluation was passed, while (2) the flame retardancy evaluation was unacceptable.

<Summary of Examples and Comparative Examples>
As shown in Examples 1 to 10, the flame-retardant insulated wire of the present embodiment has an insulating layer in (A) an ethylene polymer, (B) a metal hydroxide, and (C) in a molecule. By being composed of a flame-retardant resin composition containing a compound having a plurality of phenolic hydroxyl groups and no carboxyl group, flame retardancy and extrusion processability can be provided.

Specifically, as shown in Comparative Examples 1 to 3, in the resin composition containing (A) ethylene polymer and (B) metal hydroxide, (A) 100 parts by mass of ethylene polymer On the other hand, (2) flame retardancy evaluation passes only after (B1) 220 parts by mass or more of magnesium hydroxide is added. However, if the amount of (B1) magnesium hydroxide added to (A) the ethylene polymer is large, the fluidity of the resin composition decreases, and (1) the processability evaluation fails. Actually, as shown in Comparative Example 1, when the addition amount of (B1) magnesium hydroxide to (A) ethylene polymer is reduced, (B1) is (B1) with respect to 100 parts by mass of (A) ethylene polymer. When the amount of magnesium hydroxide reaches 165 parts by mass, (1) the workability evaluation is still unsuccessful, but (2) the flame retardancy evaluation is unsuccessful. From these results, there are some insulated wires having a resin composition containing (A) ethylene polymer and (B) metal hydroxide as an insulating layer, which satisfy both flame retardancy and extrusion processability. It turns out that it does not.

On the other hand, in Examples 1 and 2, a compound having a plurality of phenolic hydroxyl groups and no carboxyl group in the molecule (C), which is a flame retardant, was added to (A) 100 parts by mass of an ethylene polymer. On the other hand, by adding 15 parts by mass, (2) flame retardancy evaluation is passed even if the amount of (B1) magnesium hydroxide added is 125 parts by mass. Since the amount of (B1) magnesium hydroxide added can be reduced to 125 parts by mass with respect to 100 parts by mass of (A) ethylene-based polymer, (1) processability evaluation also passes.

This point is the same in Examples 5 to 7, and the compound (C) having a plurality of phenolic hydroxyl groups in the molecule and having no carboxyl group is added to (A) 100 parts by mass of the ethylene-based polymer. By adding 2 to 20 parts by mass, the amount of (B1) magnesium hydroxide added can be 130 to 160 parts by mass, and (1) processability evaluation and (2) flame retardancy evaluation pass. ..

Further, as shown in Examples 3 and 4, 30 (C) a compound having a plurality of phenolic hydroxyl groups in the molecule and no carboxyl group was added to (A) 100 parts by mass of the ethylene polymer. By adding parts by mass, (2) flame retardancy evaluation is passed even if the amount of (B1) magnesium hydroxide added is 100 parts by mass. Then, in Examples 3 and 4, the amount of (B1) magnesium hydroxide added can be reduced to 100 parts by mass with respect to 100 parts by mass of (A) ethylene polymer, and thus (1) workability evaluation. Needless to say, the extrusion torque of the extruder can be made smaller than that of the first and second embodiments, so that the manufacturing efficiency of the electric wire can be further improved.

As shown in Examples 1 to 10, it can be seen that ester derivatives of gallate such as (C1) methyl gallate and (C2) propyl gallate are useful as flame retardants. In particular, in Example 6, flame retardancy is achieved even by adding only 2 parts by mass of (A) a compound having a plurality of phenolic hydroxyl groups and no carboxyl group in the molecule to 100 parts by mass of the ethylene polymer. It has passed the sex evaluation (VW-1 combustion test). (B) It is considered that this is a synergistic effect due to the combined use of a metal hydroxide and a flame retardant having a different action. Further, when Example 1 and Example 2 or Example 3 and Example 4 are compared, there is almost no difference in characteristics between (C1) methyl gallate and (C2) propyl gallate. .. Therefore, it is presumed that ethyl gallate and butyl gallate, which are ester derivatives of the same gallate, also exhibit the same characteristics. Further, as shown in Examples 8 to 10, when (B) aluminum hydroxide is used as the (B) metal hydroxide, even if it is added up to 180 parts by mass, only (2) flame retardancy evaluation is performed. None (1) The result was that the workability evaluation was also passed. The reason is unknown, but it is considered that the magnitude of friction at the time of collision between metal hydroxide particles is related.

On the other hand, as shown in Comparative Example 4 and Comparative Example 5, the resin composition has (A) ethylene polymer, (B1) magnesium hydroxide, and a plurality of phenolic hydroxyl groups in the molecule, but also has a carboxyl group. When it is composed of (C5) gallic acid, which is a compound having the compound, (2) flame retardancy evaluation is passed, while (1) processability evaluation is unacceptable. This is because (C5) gallic acid has a carboxyl group in the molecule, so that the carboxyl group in the (C5) gallic acid molecule is bonded to the surface of (B1) magnesium hydroxide, and the fluidity of the resin composition Is thought to be due to a decrease in.

Further, as shown in Comparative Example 6, (C) a compound having a plurality of phenolic hydroxyl groups and no carboxyl group in the molecule was added in an amount of 15 parts by mass with respect to 100 parts by mass of the ethylene-based polymer (A). Even in this case, if (B1) the amount of magnesium hydroxide added is 80 parts by mass, (2) the flame retardancy evaluation fails. Therefore, when combined with the results of Examples 3, 4, 5, and 6, the amount of (B) metal hydroxide is 100 parts by mass or more and 180 parts by mass with respect to 100 parts by mass of (A) ethylene polymer. It can be seen that it is preferable to use less than one part.

Further, regarding (1) workability evaluation, as shown in Examples 1 to 10 and Comparative Examples 1 to 6, the extrusion torque is approximately proportional to the amount of (B1) magnesium hydroxide added. However, when (C2) propyl gallate of Example 2 or Example 4 is added, the extrusion torque is smaller than that of Example 1 or Example 3 in which the amount of (B1) magnesium hydroxide added is the same. You can see that it is. One of the reasons is that propyl gallate (melting point 150 ° C.), whose melting point of the compound is lower than the processing temperature (160 ° C.) of the resin composition, acts as one of the lubricants to improve the fluidity of the resin composition. It is possible that it was improved. Therefore, from the viewpoint of improving the extrusion processability, it can be said that it is preferable to use (C2) propyl gallate as the compound (C) having a plurality of phenolic hydroxyl groups in the molecule and not having a carboxyl group.

Further, regarding (2) flame retardancy evaluation, as shown in Examples 1 to 10 and Comparative Examples 1 to 6, the oxygen index must be at least 30 or more in order to pass VW-1. Is considered to be one of the requirements. However, as shown in Comparative Example 1, even if the oxygen index is 30 or more, VW-1 may be rejected. Therefore, the flame retardancy evaluation of the electric wire should be performed based on VW-1. It can also be said that it is preferable.

Regarding (3) low temperature characteristic evaluation carried out as a reference test, as shown in Examples 4 to 7, Comparative Example 4 and Comparative Example 5, (C) has a plurality of phenolic hydroxyl groups in the molecule. As a compound having no carboxyl group, (C2) propyl gallate (melting point 150 ° C.), (C3) 2,3,4-trihydroxybenzophenone (melting point 140 ° C.), and (C4) bisphenol A (melting point 158 ° C.) are used. The low temperature characteristics of Examples 4 to 7 used were passed, and the low temperature characteristics of Comparative Examples 4 and 5 using (C5) phenolic acid (melting point 285 ° C.) were unacceptable. This is because in Comparative Example 4 and Comparative Example 5 using (C5) gallic acid (melting point 285 ° C.) having a melting point higher than the processing temperature at the time of manufacturing the flame-retardant insulated wire, it did not melt at the normal processing temperature. It is considered that this is because it exists as an agglomerate in the resin composition and is likely to be a starting point of mechanical destruction. Therefore, propyl gallate (melting point 150 ° C.), (C3) 2,3,4-trihydroxybenzophenone (melting point 140 ° C.), and (C4) bisphenol A (melting point 158 ° C.), which have low melting points, are preferable. .. Therefore, in order to pass the low temperature characteristics, the melting point of the compound (C) having a plurality of phenolic hydroxyl groups in the molecule and not having a carboxyl group is higher than the processing temperature at the time of manufacturing the flame-retardant insulated wire. It can be said that it is preferable to use one.

The present invention is not limited to the above-described embodiments and examples, and various modifications can be made without departing from the gist thereof.

1 Conductor 2 Insulation layer 2a Insulation inner layer 2b Insulation outer layer 4 Sheath 5 Interposition 6 Separator 10, 20 Flame-retardant insulated wire 30 Flame-retardant cable

Claims (4)

It has a conductor and an insulating layer coated around the conductor.
The insulating layer comprises a flame-retardant resin composition containing an ethylene polymer, a metal hydroxide, and a compound having a plurality of phenolic hydroxyl groups and no carboxyl group in the molecule.
The flame-retardant resin composition contains 100 parts by mass or more and 180 parts by mass or less of the metal hydroxide with respect to 100 parts by mass of the ethylene polymer.
The flame retardant resin composition, relative to the ethylene polymer 100 parts by weight, looking containing the compound 2 parts by mass or more,
The compound is a flame-retardant insulated wire which is an ester derivative of gallic acid. In the flame-retardant insulated wire according to claim 1,
The compound, methyl gallate, at least one compound selected from propyl gallate and 2,3,4-trihydroxy-benzo phenol emissions or Ranaru group, flame-retardant insulated wire. It has a core including an insulated wire composed of a conductor and an insulating layer coated around the conductor, and a sheath provided around the core.
The sheath is composed of a flame-retardant resin composition containing an ethylene polymer, a metal hydroxide, and a compound having a plurality of phenolic hydroxyl groups and no carboxyl group in the molecule.
The flame-retardant resin composition contains 100 parts by mass or more and 180 parts by mass or less of the metal hydroxide with respect to 100 parts by mass of the ethylene polymer.
The flame retardant resin composition, relative to the ethylene polymer 100 parts by weight, looking containing the compound 2 parts by mass or more,
The compound is a flame-retardant cable which is an ester derivative of gallic acid. In the flame-retardant cable according to claim 3,
The compound, methyl gallate, at least one compound selected from propyl gallate and 2,3,4-trihydroxy-benzo phenol emissions or Ranaru group, flame-retardant cables.

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