JP6631157B2 - Railway vehicle electric wire and railway vehicle cable using phosphorus-free non-halogen flame-retardant resin composition - Google Patents

Description

The present invention relates to a railway vehicle electric wire and a railway vehicle cable using a phosphorus-free non-halogen flame-retardant resin composition.

  BACKGROUND ART In recent years, non-halogen flame-retardant electric wires and cables that do not use polyvinyl chloride or halogen-based flame retardants and have a small environmental load have rapidly spread as so-called eco-electric wires and cables.

  In conventional non-halogen flame-retardant electric wires and cables, it is common to use a resin composition in which a non-halogen flame retardant such as magnesium hydroxide is mixed with polyolefin as an insulator of the electric wire or a sheath of the cable (for example, Patent Document 1).

JP-A-10-287777

  However, in order to use a non-halogen flame retardant such as magnesium hydroxide to achieve high flame retardancy in a vertical tray combustion test that passes overseas flame retardant standards (eg, EN, DIN, BS). It is necessary to mix a large amount of non-halogen flame retardants. As a result, there is a problem that properties such as mechanical strength, flexibility, heat resistance, and whitening resistance are reduced. In particular, in order to obtain electric wires and cables suitable for railway vehicles, development of a halogen-free flame-retardant resin composition that can solve the above-mentioned problems has been desired.

  On the other hand, there is a method to reduce the amount of non-halogen flame retardants by adding a flame retardant auxiliary such as red phosphorus.However, phosphorus-based flame retardant auxiliary such as red phosphorus generates harmful phosphine during combustion or phosphorus during disposal. It has been pointed out that there is a concern of generating acid and contaminating groundwater veins. For this reason, the use of red phosphorus and the like has recently been refrained from being used, and there has been a demand for the development of phosphorus-free non-halogen flame-retardant wires and cables having excellent flame retardancy.

Therefore, the present invention solves the above-mentioned problems of the prior art, has high flame retardancy that passes overseas flame retardant standards (any one or more of EN, DIN, and BS), and It intended to provide mechanical strength, flexibility, excellent heat resistance and whitening resistance, a railway vehicle wire and rail vehicles cable with no phosphorus-based halogen-free flame retardant resin composition suitable for rail vehicles And

The present invention, in order to achieve the above object, provides a railway vehicle wire and rail vehicles cable with no phosphorus-based halogen-free flame retardant resin composition described below.

[1] Copolymer (A) of ethylene and α-olefin having 3 to 8 carbon atoms, ethylene-vinyl acetate copolymer (B) and copolymer of ethylene and α-olefin having 3 to 8 carbon atoms A maleic acid-modified ethylene copolymer (C) as a polymer component is contained as a resin component, and the content of the copolymer (A) is 20 to 80% by mass in the resin component. The content of the copolymer (C) is 5 to 30% by mass in the resin component, and 100 to 250 parts by mass of the fatty acid-treated magnesium hydroxide and 1 to 15 parts by mass of the silicone rubber with respect to 100 parts by mass of the resin component. A phosphorus-free non-halogen flame-retardant resin composition containing 2 to 20 parts by mass of carbon black having a mass part and a surface area of 11 to 99 m ² / g.
[2] The phosphorus-free non-halogen flame-retardant resin composition according to [1], wherein the copolymer (A) is polymerized with a metallocene catalyst.
[3] The content of the ethylene-vinyl acetate copolymer (B) is 15 to 75% by mass in the resin component, and the non-phosphorus-free non-halogenated resin according to the above [1] or [2], Flammable resin composition.
[4] An electric wire comprising an insulating layer made of the phosphorus-free non-halogen flame-retardant resin composition according to any one of [1] to [3].
[5] A cable comprising a sheath made of the phosphorus-free non-halogen flame-retardant resin composition according to any one of [1] to [3].
[6] The cable according to [5], comprising the electric wire according to [4].

According to the present invention, it has high flame retardancy that passes overseas flame retardant standards (any one or more of EN, DIN, and BS), and has mechanical strength, flexibility, heat resistance, and whitening resistance. excellent, it is possible to provide a railway vehicle wire and rail vehicles cable with no phosphorus-based halogen-free flame retardant resin composition suitable for a railway vehicle.

It is a cross section showing typically an example of an electric wire concerning an embodiment of the invention. It is a cross section showing typically an example of a cable concerning an embodiment of the invention.

(Phosphorus-free non-halogen flame retardant resin composition)
The phosphorus-free non-halogen flame-retardant resin composition according to the embodiment of the present invention comprises a copolymer of ethylene and an α-olefin having 3 to 8 carbon atoms (A), and an ethylene-vinyl acetate copolymer (B). ) And a maleic acid-modified ethylene copolymer (C) having ethylene and an α-olefin having 3 to 8 carbon atoms as a copolymer component, as a resin component, and the content of the copolymer (A) is as follows: The content of the maleic acid-modified ethylene copolymer (C) is 20 to 80% by mass in the resin component, and the content of the maleic acid-modified ethylene copolymer (C) is 5 to 30% by mass in the resin component. 100 to 250 parts by mass of magnesium hydroxide, 1 to 15 parts by mass of silicone rubber, and 2 to 20 parts by mass of carbon black having a surface area of 11 to 99 m ² / g.

<Copolymer (A)>
The phosphorus-free non-halogen flame-retardant resin composition according to the embodiment of the present invention contains a copolymer (A) of ethylene and an α-olefin having 3 to 8 carbon atoms as a resin component.

  As the copolymer (A), for example, ethylene-propylene copolymer, ethylene-butene copolymer, ethylene-hexene copolymer, ethylene-octene copolymer and the like can be used. Examples of the α-olefin having 3 to 8 carbon atoms include propylene, 1-butene, 4-methyl-1-pentene, 1-hexene, 1-octene and the like. Of these, 1-butene and 1-octene are more preferred.

  The copolymer (A) is preferably obtained by polymerizing ethylene and an α-olefin having 3 to 8 carbon atoms using a metallocene catalyst. Thereby, a high-strength and flexible copolymer having a narrow molecular weight distribution can be obtained. Those having a hardness of 60 to 95 measured by a general hardness meter are preferable, and those having a hardness of 65 to 90 are more preferable.

  The content of the copolymer (A) is 20 to 80% by mass in the resin component. Preferably, it is 30 to 70% by mass. If the amount is less than 20 parts by mass, the flexibility is poor, and if it exceeds 80% by mass, the mechanical strength (tensile strength) and the flame retardancy are inferior.

<Ethylene-vinyl acetate copolymer (B)>
The phosphorus-free non-halogen flame-retardant resin composition according to the embodiment of the present invention contains an ethylene-vinyl acetate copolymer (B) as a resin component.

  The ethylene-vinyl acetate copolymer (B) contains vinyl acetate, and can suppress combustion by causing an endothermic reaction by deacetic acid when the composition is burned and thermally decomposed.

  The ethylene-vinyl acetate copolymer (B) preferably has a vinyl acetate content (VA amount) of 20 to 50% by mass, more preferably 25 to 40% by mass.

  The content of the ethylene-vinyl acetate copolymer (B) is preferably from 15 to 75% by mass in the resin component. The lower limit of the content is more preferably 30% by mass, and still more preferably 35% by mass. The upper limit of the content is more preferably 70% by mass, and further preferably 65% by mass.

<Maleic acid-modified ethylene copolymer (C)>
The phosphorus-free non-halogen flame-retardant resin composition according to the embodiment of the present invention is a maleic acid-modified ethylene copolymer containing ethylene and an α-olefin having 3 to 8 carbon atoms as resin components. (C) is contained. The maleic acid-modified ethylene copolymer (C) can be obtained by modifying a copolymer of ethylene and an α-olefin having 3 to 8 carbon atoms with maleic anhydride. The amount of modification with maleic acid is not particularly limited.

  Maleic acid-modified ethylene copolymer (C) adheres to the interface between ethylene-vinyl acetate copolymer (B) and fatty acid-treated magnesium hydroxide to improve mechanical strength (tensile strength) and heat resistance Have the function to let.

  As a copolymer of ethylene and an α-olefin having 3 to 8 carbon atoms, for example, ethylene-propylene copolymer, ethylene-butene copolymer, ethylene-hexene copolymer, ethylene-octene copolymer and the like can be used. Examples of the α-olefin having 3 to 8 carbon atoms include propylene, 1-butene, 4-methyl-1-pentene, 1-hexene, 1-octene and the like. Of these, 1-butene and 1-octene are more preferred.

  The copolymer is preferably obtained by polymerizing ethylene and an α-olefin having 3 to 8 carbon atoms using a metallocene catalyst, similarly to the copolymer (A). .

  The content of the maleic acid-modified ethylene copolymer (C) (for example, maleic acid-modified ethylene-butene copolymer) is 5 to 30% by mass in the resin component. Preferably, it is 5 to 20% by mass. If the amount is less than 5% by mass, the adhesion between the ethylene-vinyl acetate copolymer (B) and the fatty acid-treated magnesium hydroxide is weak, and sufficient heat resistance cannot be obtained. If the content exceeds 30% by mass, the adhesion between the ethylene-vinyl acetate copolymer (B) and the fatty acid-treated magnesium hydroxide is strong, and the flexibility is reduced.

<Magnesium hydroxide treated with fatty acid>
The phosphorus-free non-halogen flame-retardant resin composition according to the embodiment of the present invention contains 100 to 250 parts by weight of a fatty acid-treated magnesium hydroxide based on 100 parts by weight of the resin component in order to improve the flame retardancy. I do. Preferably, it contains 130 to 200 parts by mass. If the amount is less than 100 parts by mass, the flame retardancy is insufficient. If the amount exceeds 250 parts by mass, the mechanical strength is reduced and the flexibility is poor.

<Silicone rubber and carbon black>
The phosphorus-free non-halogen flame-retardant resin composition according to the embodiment of the present invention contains silicone rubber and carbon black having a surface area of 11 to 99 m ² / g in order to improve whitening resistance.

  An electric wire coated with a resin composition to which a large amount of magnesium hydroxide treated with a fatty acid is added tends to cause whitening when its surface is rubbed. This is considered to be white because a small gap is generated between the resin and the magnesium hydroxide when rubbed, and irregular reflection is likely to occur.

  For example, when silane-treated magnesium hydroxide is used in order to prevent the formation of the gap, the adhesion between the resin and the magnesium hydroxide is improved, so that the whitening is suppressed to some extent, but the flexibility is significantly reduced.

  When carbon black having a strong color and a large surface area is used to suppress diffuse reflection, whitening is suppressed to some extent, but is not yet sufficient.

  Since silicone rubber has an effect of reducing frictional force, when rubbed, the surface of the electric wire becomes slippery and a minute gap between the resin and the magnesium hydroxide is hardly generated, but it is not sufficient yet.

  Only when the effect of the carbon black and the effect of the silicone rubber are combined, the whitening resistance becomes good, which is a new finding that has never been seen before.

  The phosphorus-free non-halogen flame-retardant resin composition according to the embodiment of the present invention contains 1 to 15 parts by mass of silicone rubber based on 100 parts by mass of the resin component. Preferably, it is contained in an amount of 2 to 12 parts by mass. If the amount is less than 1 part by mass, the whitening resistance is insufficient, and if the amount exceeds 15 parts by mass, slippage occurs in the extruder, which makes molding difficult.

  As the silicone rubber, general ones such as dimethylsiloxane, methylvinylsiloxane and methylphenylpolysiloxane may be used, and there is no particular limitation. These may be used alone or in combination of two or more.

Further, the phosphorus-free non-halogen flame-retardant resin composition according to the embodiment of the present invention contains 2 to 20 parts by mass of carbon black having a surface area of 11 to 99 m ² / g based on 100 parts by mass of the resin component. . Preferably, the content is 3 to 15 parts by mass. If the amount is less than 2 parts by mass, the whitening resistance is insufficient, and if the amount is more than 20 parts by mass, the flexibility is reduced.

Carbon black having a surface area of 11 to 99 m ² / g is used. If the surface area is less than 11 m ² / g, the whitening resistance is insufficient, and if it exceeds 99 m ² / g, the flexibility is reduced. Carbon black having a surface area within the above range may be used alone or in combination of two or more.

<Other ingredients>
In the embodiment of the present invention, in addition to the above components, other polymers, inorganic fillers, stabilizers, antioxidants, plasticizers, lubricants, coloring agents, ultraviolet absorbers, light stabilizers, crosslinking agents, crosslinking aids Various additives such as agents can be blended.

  The phosphorus-free non-halogen flame-retardant resin composition according to the embodiment of the present invention is preferably subjected to crosslinking after being molded into an insulating layer of an electric wire or a cable sheath. A conventionally known method can be used for the crosslinking, and is not particularly limited. Methods such as chemical crosslinking (organic peroxide crosslinking), radiation crosslinking, and silane crosslinking can be used.

〔Electrical wire〕
An electric wire according to an embodiment of the present invention includes a conductor, and an insulating layer coated on the outer periphery of the conductor and made of the phosphorus-free non-halogen flame-retardant resin composition according to the embodiment of the present invention. And

FIG. 1 is a cross-sectional view schematically illustrating an example of an electric wire according to an embodiment of the present invention.
As shown in FIG. 1, an electric wire 10 according to the present embodiment includes a conductor 1 and an insulating layer 2 coated on the outer periphery of the conductor 1. As the conductor 1 to be covered, for example, a conductor having an outer diameter of about 0.15 to 7 mmφ can be used. A conductor obtained by twisting tin-plated annealed copper wire can be preferably used, but is not limited thereto. The number of conductors 1 is not limited to one as shown in FIG. 1, but may be plural.

  The insulating layer 2 is composed of the above-mentioned phosphorus-free non-halogen flame-retardant resin composition according to the embodiment of the present invention. After coating as an insulating layer by molding means such as extrusion coating, the phosphorus-free non-halogen flame-retardant electric wire 10 can be obtained by crosslinking the phosphorus-free non-halogen flame-retardant resin composition by a method such as electron beam irradiation. it can. The extrusion coating is performed by kneading the phosphorus-free non-halogen flame-retardant resin composition before cross-linking with a roll, a Banbury, an extruder, or the like, and connecting the obtained pellet compound and a conductor to a conventionally known wire provided with a crosshead die. It can be carried out by extruding an electric wire with an extruder.

  In this embodiment, the insulating layer may have a single layer as shown in FIG. 1 or may have a multilayer structure. Further, a separator, a braid, and the like may be provided as necessary.

〔cable〕
The cable according to the embodiment of the present invention is characterized in that the phosphorus-free non-halogen flame-retardant resin composition according to the embodiment of the present invention is used as a coating material (sheath or insulating layer and sheath).

FIG. 2 is a cross-sectional view schematically illustrating an example of the cable according to the embodiment of the present invention.
As shown in FIG. 2, a cable 20 according to the present embodiment includes a two-core stranded wire in which a conductor 1 is coated with an insulating layer 2, two of which are twisted together with an interposition 3 such as paper, and an outer periphery thereof. And an extrusion-coated sheath 4. The present invention is not limited to the two-core stranded wire, but may be one electric wire (single core) or a multi-core stranded wire other than the two-core stranded wire. After applying a press winding tape to the outer periphery of the two-core stranded wire, the outer periphery may be extrusion-coated with the sheath 4.

  The sheath 4 is made of the phosphorus-free non-halogen flame-retardant resin composition according to the embodiment of the present invention. The insulating layer 2 is not limited to the embodiment constituted by the above-mentioned phosphorus-free non-halogen flame-retardant resin composition. (Preferably). After coating as an insulating layer or a sheath layer by molding means such as extrusion coating, a phosphorus-free non-halogen flame-retardant cable 20 is formed by crosslinking the phosphorus-free non-halogen flame-retardant resin composition by a method such as electron beam irradiation. Obtainable.

  In the present embodiment, the sheath may have a single layer as shown in FIG. 2 or may have a multilayer structure. Further, a separator, a braid, and the like may be provided as necessary.

  Hereinafter, the present invention will be described in more detail based on Examples and Comparative Examples, but the present invention is not limited thereto.

  The electric wire 10 having the structure of FIG. 1 was manufactured by the following method and evaluated.

(1) Preparation of phosphorus-free non-halogen flame-retardant resin composition The materials shown in Tables 1 and 2 were blended in the proportions described, kneaded and mixed with an open roll mixer heated to 100 ° C., and pelletized. Resin compositions of Examples and Comparative Examples were prepared. The materials used are as shown in Table 3.

(2) Preparation of electric wire The resin composition prepared in the above (1) was placed on a tin-plated copper stranded conductor having a conductor diameter of 2.3 mm using a 40 mm extruder (L / D = 22) maintained at 100 ° C. To a thickness of 1.1 mm at an extrusion speed of 40 m / min. Thereafter, crosslinking was performed for 3 minutes with steam of 13 kg / cm ² to obtain an electric wire.

(3) Evaluation Using the electric wire manufactured as described above, mechanical strength (tensile strength, elongation), flexibility (100% modulus), heat resistance (residual tensile strength, residual elongation), flame retardancy Properties (VTFT) and whitening resistance were evaluated as follows. The evaluation results are shown in Tables 1 and 2.

(Mechanical strength)
A conductor was pulled out of the manufactured electric wire, and the tensile strength and tensile elongation of each tube-shaped sample were measured by performing a tensile test in accordance with JIS C3005. The target was a tensile strength of 7 MPa or more and an elongation of 350% or more. Those that were equal to or higher than the target value were accepted, and those that were less than the target value were rejected.

(Flexibility)
A 100% modulus was measured in the tensile test. The 100% modulus was targeted at 5 MPa or less. Those below the target value were accepted, and those exceeding the target value were rejected.

(Heat-resistant)
Each sample after the measurement of the mechanical strength was put into a heat aging tester at 150 ° C. for 96 hours, taken out, and the tensile test was performed again to measure the mechanical strength (tensile strength and elongation). , And initial values (values before the heat aging test). Specifically, residual tensile strength (%) = (tensile strength after thermal aging test / tensile strength before thermal aging test) × 100, residual elongation (%) = (elongation after thermal aging test) / Elongation before heat aging test) × 100. Each of the residual tensile strength ratio and the residual tensile elongation ratio was aimed at 80% or more. Those that were equal to or higher than the target value were accepted, and those that were less than the target value were rejected.

(Flame retardance)
The flame retardancy was measured by a vertical tray combustion test (VTFT) based on BS 6853 standard and BS EN60332 Part 3-21 test method. A 3.5 m-long electric wire was made into one bundle of seven strands, 11 bundles were arranged vertically at equal intervals, and burned for 20 minutes. As a measure of high flame retardancy that passes overseas flame retardant standards (any one or more of EN, DIN, and BS), the carbonization length after self-extinguishing was set to 2.5 m or less from the lower end. Those that were below the target value were judged as acceptable (（), and those that exceeded the target value were judged as unacceptable (x).

(Whitening resistance)
The whitening resistance was evaluated by visually observing whitening when a SUS rod having a diameter of 2 mm was placed on an electric wire and the SUS rod was reciprocated 10 times under a load of 100 g. Those that did not whiten were evaluated as pass (○), and those that were whitened were evaluated as unacceptable (x).

  In Examples 1 to 13, the mechanical strength, flexibility, heat resistance, flame retardancy, and whitening resistance were all good and passed.

On the other hand, in Comparative Example 1, the addition amount of the copolymer (A) of ethylene and an α-olefin having 3 to 8 carbon atoms was smaller than the range specified in the present invention, and the flexibility was inferior.
In Comparative Example 2, the addition amount of the copolymer (A) of ethylene and an α-olefin having 3 to 8 carbon atoms exceeds the range specified by the present invention, and the mechanical strength (tensile strength) and Poor flame retardancy.
In Comparative Example 3, the amount of the maleic acid-modified ethylene copolymer (C) added was less (not contained) than the range specified in the present invention, and the mechanical strength (tensile strength) and heat resistance were poor. .
In Comparative Example 4, the addition amount of the maleic acid-modified ethylene copolymer (C) exceeds the range specified by the present invention, and the flexibility is inferior.
In Comparative Example 5, the amount of the magnesium hydroxide treated with the fatty acid was smaller than the range specified in the present invention, and the flame retardancy was poor.
In Comparative Example 6, the amount of magnesium hydroxide treated with the fatty acid exceeds the range specified by the present invention, and the mechanical strength, flexibility, heat resistance, and whitening resistance are poor.
Comparative Example 7 was obtained by adding silane-treated magnesium hydroxide not specified in the present invention, and was inferior in mechanical strength (elongation) and flexibility.
In Comparative Example 8, the amount of silicone rubber added was less (not contained) than the range specified in the present invention, and the whitening resistance was poor.
In Comparative Example 9, the amount of silicone rubber added exceeded the range specified by the present invention, and extrusion molding was not possible.
In Comparative Example 10, the amount of carbon black added exceeded the range specified by the present invention, and the mechanical strength (elongation) and flexibility were poor.
In Comparative Example 11, the surface area of carbon black was smaller than the range specified by the present invention, and the whitening resistance was poor.
In Comparative Example 12, the surface area of carbon black was larger than the range specified by the present invention, and the mechanical strength (elongation) and flexibility were poor.

  The present invention is not limited to the above-described embodiments and examples, and various modifications can be made.

1: conductor, 2: insulating layer, 3: intervening, 4: sheath, 10: electric wire, 20: cable

Claims (7)

Copolymer of ethylene and α-olefin having 3 to 8 carbon atoms (A), ethylene-vinyl acetate copolymer (B), and copolymer component of ethylene and α-olefin having 3 to 8 carbon atoms As a resin component, the content of the copolymer (A) is 20 to 80% by mass in the resin component, and the ethylene-vinyl acetate copolymer The content of (B) is 15 to 75% by mass in the resin component, and the content of the maleic acid-modified ethylene copolymer (C) is 5 to 30% by mass in the resin component. 100 to 250 parts by mass of fatty acid-treated magnesium hydroxide, 1 to 15 parts by mass of silicone rubber, and 2 to 2 parts by mass of carbon black having a surface area of 11 to 99 m ² / g measured based on ASTM D 1765-01 . 20 parts by weight is contained, a railcar conductive wire having an insulating layer made of non-phosphorus-based halogen-free flame retardant resin composition obtained by crosslinking,
The electric wire for a railway vehicle, wherein the insulating layer has a residual tensile strength and a residual elongation of 80% or more after a heat aging test at 150 ° C. for 96 hours . Copolymer of ethylene and α-olefin having 3 to 8 carbon atoms (A), ethylene-vinyl acetate copolymer (B), and copolymer component of ethylene and α-olefin having 3 to 8 carbon atoms As a resin component, the content of the copolymer (A) is 20 to 80% by mass in the resin component, and the ethylene-vinyl acetate copolymer The content of (B) is 15 to 75% by mass in the resin component, and the content of the maleic acid-modified ethylene copolymer (C) is 5 to 30% by mass in the resin component. 100 to 250 parts by mass of fatty acid-treated magnesium hydroxide, 1 to 15 parts by mass of silicone rubber, and 2 to 2 parts by mass of carbon black having a surface area of 11 to 99 m ² / g measured based on ASTM D 1765-01 . 20 parts by weight is contained, a railway vehicle cable having a sheath made of non-phosphorus-based halogen-free flame retardant resin composition obtained by crosslinking,
The cable for a railway vehicle, wherein the sheath has a tensile strength residual ratio and an elongation residual ratio of at least 80% after a heat aging test at 150 ° C. for 96 hours . The electric wire for a railway vehicle according to claim 1, wherein the copolymer (A) is polymerized by a metallocene catalyst. The electric wire for a railway vehicle according to claim 1, wherein the content of the ethylene-vinyl acetate copolymer (B) is 15 to 75% by mass in the resin component. The cable according to claim 2, wherein the copolymer (A) is polymerized by a metallocene catalyst. The cable for a railway vehicle according to claim 2, wherein the content of the ethylene-vinyl acetate copolymer (B) is 15 to 75% by mass in the resin component. Railway vehicle cable according to claim 2, characterized in that it comprises a wire for a railway vehicle according to claim 1.

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