JP2014053247A - Railway vehicle electric wire and railway vehicle cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a railway vehicle electric wire and a railway vehicle cable that are excellent in characteristics such as fire retardancy, oil resistance, and mechanical strength, and that use a non-halogen crosslinked resin composition that combines fuel resistance and cold resistance.SOLUTION: A railway vehicle electric wire includes: a conductor 1; and an insulator layer 3 comprising a non-halogen crosslinked resin composition formed on an outer peripheral side of the conductor 1. The non-halogen crosslinked resin composition includes 80-200 pts.mass of a metalhydroxide based on 100 pts.mass of a basis polymer including 20-70 pts.mass of an ethylene-vinyl acetate copolymer (EVA) in which a vinyl acetate content (VA content) is at least 60 mass%, at least 25 pts.mass of EVA in which a VA content is 30-50 mass%, and 1-30 pts.mass of a maleic acid modified ethylene α olefinic copolymer that is modified by maleic acid anhydride.

Description

  The present invention relates to a railway vehicle wire and a railway vehicle cable using a non-halogen crosslinked resin composition that does not generate a halogen-based gas during combustion and is excellent in mechanical properties, fuel resistance, flame resistance, and cold resistance. It is.

  Conventionally, as a flame retardant resin composition not containing a halogen compound, a composition obtained by adding a metal hydroxide such as magnesium hydroxide to a polyolefin resin has been used. Since these compositions do not generate toxic gases such as hydrogen chloride or dioxin during combustion, they can prevent the generation of toxic gases during fires, secondary disasters, etc. Not. As these non-halogen flame retardant resin compositions, resin compositions obtained by mixing a large amount of non-halogen flame retardants such as magnesium hydroxide with polyolefin are generally used. In order to improve the flame retardancy, a high amount of flame retardant is filled, but there is a problem that the mechanical characteristics are lowered and the intended electric wire cannot be obtained.

  On the other hand, in Europe where the railway vehicle network is developed, the adoption of the regional standard called EN standard (European standard) is spreading. In such a standard, electric wires and cables used for railway vehicles are required to use a non-halogen material having high flame retardancy because there is a risk of causing a major accident due to the failure.

  In the past, in order to meet this demand, the present inventors have coated a conductor and have an inner layer having an insulator containing an ethylene ethyl acrylate copolymer, and coated the inner layer with an ethylene vinyl acetate copolymer and a non-halogen flame retardant. An insulated wire including a cross-linked outer layer was proposed (see Patent Document 1). Such a non-halogen insulated wire has characteristics excellent in desired flame retardancy, oil resistance and mechanical strength, but it is not without room for improvement.

  That is, in recent years, electric wires and cables excellent in fuel resistance and cold resistance in addition to characteristics such as flame retardancy, oil resistance and mechanical strength have been demanded.

  For rail vehicle electric wires and cables that comply with EN standards, the types that must pass the fuel resistance test specified in EN60881-1-3 and the cold resistance test specified in EN60881-1-4.4.3 However, it cannot be said that sufficient studies have been made on this point, and the present situation is that electric wires and cables having these required characteristics have not been obtained.

  On the other hand, as shown in Patent Document 2, mechanical properties, flame retardancy, oil resistance and cold resistance are improved by blending an ethylene-ethyl acrylate copolymer with an acrylic elastomer and adding a metal hydroxide. I am letting.

JP 2010-097881 A Japanese Patent Laid-Open No. 09-104797

  However, the blend of acrylic elastomer and ethylene-ethyl acrylate copolymer has an embrittlement temperature of −35 ° C., which is higher than −40 ° C., which is an index of cold resistance required for vehicles, and is insufficient. It was.

  Accordingly, an object of the present invention is to solve the above-mentioned problems, and is excellent for characteristics such as flame retardancy, oil resistance, mechanical strength, and for railway vehicles using a non-halogen crosslinked resin composition having both fuel resistance and cold resistance. It is to provide electric wires and cables for railway vehicles.

  In order to achieve the above object, the invention of claim 1 is an electric wire for a railway vehicle having a conductor and an insulating layer made of a non-halogen cross-linked resin composition formed on the outer peripheral side of the conductor, the non-halogen cross-linked resin Composition is 20 to 70 parts by mass of ethylene vinyl acetate copolymer (EVA) having a vinyl acetate content (VA amount) of 60 mass% or more, 25 parts by mass or more of EVA having a VA amount of 30 to 50 mass%, and anhydrous maleic acid. 80 to 200 parts by mass of metal hydroxide for 100 parts by mass of base polymer containing 1 to 30 parts by mass of maleic acid-modified ethylene α-olefin copolymer modified with acid It is an electric wire.

  The invention according to claim 2 is the electric wire for railway vehicles according to claim 1, wherein the maleic acid-modified ethylene α-olefin copolymer is a comonomer of α-olefin having 3 to 8 carbon atoms.

  The invention of claim 3 is a railway vehicle cable having a plurality of electric wires and a sheath made of a non-halogen cross-linked resin composition formed on the outside of the plurality of electric wires, wherein the non-halogen cross-linked resin composition is 20 to 70 parts by mass of an ethylene vinyl acetate copolymer (EVA) having a vinyl acetate content (VA amount) of 60 mass% or more, 25 parts by mass or more of EVA having a VA amount of 30 to 50 mass%, modified with maleic anhydride A railway vehicle cable comprising 80 to 200 parts by mass of a metal hydroxide with respect to 100 parts by mass of a base polymer containing 1 to 30 parts by mass of a maleic acid-modified ethylene α-olefin copolymer. .

  A fourth aspect of the present invention is the railway vehicle cable according to the third aspect, wherein the maleic acid-modified ethylene α-olefin copolymer is an α-olefin comonomer having 3 to 8 carbon atoms.

  Railway vehicle wires and railcar cables using the non-halogen crosslinked resin composition of the present invention do not generate toxic gas during combustion, and have excellent effects of having high flame resistance, oil resistance and cold resistance. To do.

It is sectional drawing of the cable for rail vehicles of this invention. 1 is a cross-sectional view of a railway vehicle electric wire according to the present invention.

  A preferred embodiment of the present invention will be described below in detail with reference to the accompanying drawings.

  As shown in FIG. 2, the electric wire for railway vehicles according to the embodiment of the present invention includes a conductor (for example, a tin-plated copper conductor 1) and an insulating layer (for example, an inner layer insulator 2 and an outer layer) formed on the conductor. A railcar electric wire 5 having an insulator 3).

  In the present invention, a halogen-free crosslinked resin composition is used as the outer layer insulator 3 of the electric wire 5 for railway vehicles.

  This non-halogen crosslinked resin composition has an ethylene vinyl acetate copolymer (EVA) having a vinyl acetate content (VA amount) of 60 mass% or more, 20 to 70 parts by mass, and a vinyl acetate content (VA amount) of 30 to 50 mass%. 25 parts by mass or more of ethylene vinyl acetate copolymer and 1 to 30 parts by mass of maleic acid-modified ethylene α-olefin copolymer modified with maleic anhydride. It contains 80 to 200 parts by mass.

  There is no restriction | limiting in particular as a material which comprises the insulating layer (inner layer insulator 2) used for this Embodiment, Generally, the resin composition used for a non-halogen electric wire and a cable can be used. In addition, as long as it is a non-halogen material, engineer plastic or the like can be used. In particular, if electrical characteristics are important, polyolefins such as ethylene α-olefin copolymer, HDPE, LDPE, LLDPE, VLDPE, EPDM, EVA, EEA, EMA, etc. are used as the base polymer, and inorganic fillers such as talc and clay are mixed. If flame retardancy is important, a mixture of the above-mentioned polyolefin with a non-halogen flame retardant such as a metal hydroxide is preferred. Note that the insulating layer may be formed only by the outer layer insulator 3 without using the inner layer insulator 2.

  There is no restriction | limiting in particular as a material which comprises the conductor used for this Embodiment, The copper, copper alloy, metal plating copper, aluminum, etc. which are conventionally used frequently can be used. For example, the tin plating copper conductor 1 shown in FIG. 2 can be mentioned as a suitable example. Moreover, this conductor may be comprised from the single solid strand, and the strand wire which twisted the some metal strand may be sufficient. Further, the thickness of the conductor is not particularly limited.

  In addition, as shown in FIG. 1, the railway vehicle cable according to the embodiment of the present invention twists a plurality of insulated wires 15 provided with an insulating layer 11 made of polyolefin such as ethylene propylene rubber on a conductor 10, A tape layer 12a such as a resin tape (PET tape or the like) is applied to the outer periphery of the twisted insulated electric wire 15, and a metal layer 13 or the like made of a metal braid or the like is applied to the outside, followed by a tape layer 12b. A railcar cable 20 is formed by applying a sheath 14 as an extrusion coating on the outermost periphery.

  The sheath 14 of the present invention uses a non-halogen cross-linked resin composition in the same manner as the outer layer insulator 3 of the railway vehicle wire 5.

  The vinyl acetate content (VA amount) of one ethylene-vinyl acetate copolymer (EVA) in the base polymer of the non-halogen crosslinked resin composition used in the present invention is set to 60 mass% or more when the VA amount is less than 60 mass%. This is because the polarity is low and the fuel resistance decreases. Further, the amount of EVA added in the base polymer is preferably 20 to 70 parts by mass of VA amount of 60 mass% or more, the polarity is low if it is less than 20 parts by mass, the fuel resistance is lowered, and the glass transition temperature exceeds 70 parts by mass. It becomes higher and cold resistance decreases. The VA amount of the other EVA is 30 to 50 mass%. When the VA amount is less than 30 mass%, the polarity is low and the fuel resistance is lowered. When the VA amount exceeds 50 mass%, the cold resistance is lowered. The addition amount of EVA having a VA amount of 30 to 50 mass% is 25 parts by mass or more, and if it is less than 25 parts by mass, cold resistance is lowered. The addition amount of the maleic acid-modified ethylene α-olefin copolymer is 1 to 30 parts by mass, and if it is less than 1 part by mass, the adhesion between the polymer and the metal hydroxide is insufficient, the cold resistance is lowered, and 30 parts by mass is added. If it exceeds, the adhesion between the polymer and the metal hydroxide becomes too strong, and the elongation decreases. Moreover, as for carbon number of the alpha olefin type copolymer in a maleic acid modification ethylene alpha olefin type copolymer, 3-8 are preferable.

  Examples of the metal hydroxide added to the base polymer include those metal hydroxides in which magnesium hydroxide, aluminum hydroxide, calcium hydroxide and nickel are dissolved. These may be used alone or in combination of two or more. In addition, these metal hydroxides may be used which are surface-treated with a silane coupling agent, a titanate coupling agent, a fatty acid such as stearate or calcium stearate, or a fatty acid metal salt. Further, an appropriate amount of other metal hydroxide may be added.

  In the present invention, the addition amount of the flame retardant is 80 to 200 parts by mass, and if the addition amount is less than 80 parts by mass, sufficient flame retardancy cannot be obtained. To do.

  In addition to the above ingredients, additives such as antioxidants, lubricants, softeners, plasticizers, inorganic fillers, compatibilizers, stabilizers, carbon black, and colorants can be added as necessary. It is. Further, chemical crosslinking with an organic peroxide or irradiation crosslinking with radiation such as an electron beam may be performed.

  In order to further improve the performance, a flame retardant aid may be added within a range not impairing the characteristics of the present invention.

  The flame retardant resin composition of the present invention is preferably crosslinked. By performing crosslinking, the mechanical properties of the obtained flame-retardant resin composition are improved. As the cross-linking method, an electron beam cross-linking method that emits an electron beam after molding or a chemical cross-linking in which a cross-linking agent is preliminarily blended with a flame retardant resin composition and then heated and cross-linked is employed.

  In the present invention, two types of EVA having different vinyl contents (VA amounts) are used as the ethylene vinyl acetate copolymer (EVA), and this is mixed with a maleic acid-modified ethylene α-olefin copolymer to form a base. By adding a metal hydroxide as a flame retardant to the base polymer, a toxic gas is not generated during combustion, and high flame resistance, oil resistance, and cold resistance can be obtained.

  The ethylene vinyl acetate copolymer is a thermoplastic plastic produced by radical copolymerization of ethylene and vinyl acetate at high temperature and high pressure, and is excellent in flexibility and low temperature characteristics. Here, the content of vinyl acetate is generally around 40 mass%, but as the amount of VA increases, the crystallinity decreases and the flexibility increases.

  Therefore, in the present invention, a commonly used ethylene vinyl acetate copolymer having a VA amount of 30 to 50 mass% is used in combination with a flexible ethylene vinyl acetate copolymer having a VA amount of 60 mass% or more. By mixing with a modified ethylene α-olefin copolymer to form a base polymer, cold resistance and fuel resistance can be improved.

The cable was produced as follows.
Composition: 37 conductors / 0.23 mm conductor, and ethylene propylene rubber as an insulating layer is extrusion coated at 95 ° C. using a 90 mm extruder to an outer diameter of 3.1 mm, and then exposed to water vapor at 200 ° C. for 1 minute. And used as a insulated wire by peroxide crosslinking. Two obtained insulated wires were twisted to prepare a multi-core stranded wire.

  Each component shown in Table 1 and Table 2 was blended, kneaded with a pressure kneader at a starting temperature of 40 ° C. and a final temperature of 120 ° C., and then molded into a band shape to obtain a sheath material. The obtained sheath material was extrusion-coated at 95 ° C. to an outer diameter of 8.5 mm on the multifilamentary strand using a 90 mm extruder, and exposed to steam at 145 ° C. for 60 minutes for peroxide crosslinking. A cable was produced.

The cable was evaluated by the following method.
(1) Tensile test The sheath material was peeled off from the produced cable, and a tensile test was performed in accordance with EN60881-1-1. The tensile strength was set to 10 MPa or more and the elongation was set to 125% or more.
(2) Oil resistance test The sheath material is peeled off from the prepared cable, immersed in oil resistance test oil IRM902 in accordance with EN60811-1-3, heated in a thermostatic bath at 100 ° C for 72 hours, and left at room temperature for about 16 hours. Then, a tensile test was performed, and the value (residual rate) after oil immersion heating with respect to the initial value was evaluated. The target tensile strength residual rate was 70% or more, and the elongation residual rate was 60% or more.
(3) Fuel resistance test The sheath is peeled off from the prepared cable, immersed in the fuel resistance test oil IRM903 according to EN60881-1-3, heated in a constant temperature bath at 70 ° C. for 168 hours, and left at room temperature for about 16 hours. Then, a tensile test was performed, and the value (residual rate) after oil immersion heating with respect to the initial value was evaluated. The target tensile strength residual rate was 70% or more, and the elongation residual rate was 60% or more.
(4) Cold resistance test The sheath was peeled off from the produced cable, a low temperature test was performed at -40 ° C in accordance with EN60881-1-4 8.3, and an elongation of 30% or more was targeted.
(5) Flame Retardancy Test The manufactured cable was subjected to a vertical combustion test in accordance with Publication 332-1. In the judgment, those having a combustion time of 30 seconds or more after removing the flame were evaluated as x (failed), and those less than that were evaluated as ◯ (accepted).

  Examples are shown in Table 1, and Table 2 shows comparative examples prepared in the same manner as described above.

  In Examples 1 to 10, the tensile strength, elongation, oil resistance, fuel resistance, cold resistance test, and vertical combustion test all passed and showed good characteristics.

  In Comparative Example 1, EVA having a VA amount of 50 mass% and EVA having a VA amount of 46 mass% were used, and the EVA amount within the scope of the present invention was not using EVA having a VA amount of 60 mass% or more. Was insufficient.

  In Comparative Example 2, the addition amount of EVA having a VA amount of 80 mass% was 15 parts by mass, which was less than 20 to 70 parts by mass, which is the range of the present invention, and the fuel resistance was insufficient. On the contrary, in Comparative Example 3, the amount of EVA added with 80 mass% of EVA is 75 parts by mass, the amount of EVA with 46 mass% is 20 parts by mass, and the addition of EVA with a VA amount of 60 mass% or more is within the scope of the present invention. Since the amount of EVA added was more than the amount (20 to 70 parts by mass) and 30 to 50% by mass of EVA was less than 25 parts by mass, the cold resistance was insufficient.

  In Comparative Example 4, the addition amount of EVA with a VA amount of 80 mass% is 70 parts by mass, but the addition amount of EVA with a VA amount of 46 mass% is 20 parts by mass, which is less than 25 parts by mass which is the range of the present invention. The fuel resistance was insufficient.

  In Comparative Example 5, the EVA amount was 80 mass% and 60 mass% EVA, and the EVA amount of the present invention was not 30 to 50 mass%, so the cold resistance was insufficient. On the other hand, in Comparative Example 6, since the EVA with the VA amount of 28 mass% was used, the fuel resistance was insufficient.

  In Comparative Example 7, the addition amount of the maleic anhydride-modified ethylene α-olefin copolymer was 0.5 parts by mass, less than 10 to 30 parts by mass of the present invention, and the cold resistance was insufficient. On the contrary, in Comparative Example 8, the amount of maleic anhydride-modified ethylene α-olefin copolymer added was as large as 32 parts by mass, and the elongation was insufficient.

  In Comparative Example 9, the amount of magnesium hydroxide added was 75 parts by mass, less than 80 to 200 parts by mass which is the range of the present invention, and the flame retardancy was insufficient. On the contrary, in Comparative Example 10, the amount of magnesium hydroxide added was 205 parts by mass, which was more than 80 to 200 parts by mass within the scope of the present invention, and the elongation was insufficient.

  From the above, EVA having a VA amount of 60 mass% or more is 20 to 70 parts by mass, EVA having a VA amount of 30 to 50 mass% is 25 parts by mass or more, and maleic acid-modified ethylene α-olefin copolymer is 1 to 30 parts by mass. It was confirmed that 80 to 200 parts by mass of metal hydroxide was preferably added to the base polymer.

DESCRIPTION OF SYMBOLS 1 Conductor 3 Outer layer insulator 5 Railway vehicle electric wire 14 Sheath 20 Railway vehicle cable

Claims (4)

  A railway vehicle electric wire having a conductor and an insulating layer made of a halogen-free crosslinked resin composition formed on the outer peripheral side of the conductor, wherein the halogen-free crosslinked resin composition has a vinyl acetate content (VA amount) of 60 mass. % Of ethylene vinyl acetate copolymer (EVA) of 20 to 70 parts by mass, EVA of 30 to 50 mass% of VA is 25 parts by mass or more, and maleic acid modified ethylene α-olefin copolymer modified with maleic anhydride 80 to 200 parts by mass of a metal hydroxide with respect to 100 parts by mass of a base polymer containing 1 to 30 parts by mass of a railway vehicle electric wire.   The electric wire for a railway vehicle according to claim 1, wherein the maleic acid-modified ethylene α-olefin copolymer is a comonomer of an α-olefin having 3 to 8 carbon atoms.   A cable for railway vehicles having a plurality of electric wires and a sheath made of a non-halogen cross-linked resin composition formed on the outside of the plurality of electric wires, wherein the non-halogen cross-linked resin composition has a vinyl acetate content (VA) 20-70 parts by mass of ethylene vinyl acetate copolymer (EVA) having an amount of 60 mass% or more, 25 parts by mass of EVA having an amount of VA of 30-50 mass%, and maleic acid-modified ethylene α-olefin modified with maleic anhydride A railway vehicle cable comprising 80 to 200 parts by mass of a metal hydroxide with respect to 100 parts by mass of a base polymer containing 1 to 30 parts by mass of a copolymer.   The railway vehicle cable according to claim 3, wherein the maleic acid-modified ethylene α-olefin copolymer is an α-olefin comonomer having 3 to 8 carbon atoms.