JP2017082079A - Non-phosphorous non-halogen flame retardant resin composition, and wire and cable using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a non-phosphorus non-halogen flame retardant resin composition having high flame retardancy which passes oversea flame retardant standards (one or more standard of EN, DIN or BS), excellent in mechanical strength, flexibility, heat resistance and whitening resistance and suitable for railway vehicles, and a wire and a cable using the same.SOLUTION: A wire 10 has an insulation layer 2 that is applied over the outer periphery of a conductor 1 and comprises a non-phosphorus non-halogen flame retardant resin composition containing an ethylene-vinyl acetate copolymer having vinyl acetate content of 20 to 50 mass% and a maleic acid modified ethylene copolymer containing ethylene and α-olefin having 3 to 8 carbon atoms as copolymer components as resin components, wherein content of the ethylene-vinyl acetate copolymer is 50 to 95 mass% in the resin components, content of the maleic acid modified ethylene copolymer is 5 to 30 ass% in the resin components, and containing aliphatic acid-treated magnesium hydroxide of 100 to 250 pts.mass, a silicone rubber of 1 to 15 pts.mass and carbon black with a surface area of 11 to 99 m/g of 2 to 20 pts.mass based on 100 pts.mass of the resin components.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a phosphorus-free non-halogen flame retardant resin composition, and an electric wire and cable using the same.

  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 low environmental load are rapidly spreading 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 a wire insulator or cable sheath (for example, (See Patent Document 1).

Japanese Patent Laid-Open No. 10-287777

  However, using non-halogen flame retardants such as magnesium hydroxide to achieve high flame retardancy in vertical tray combustion tests that pass overseas flame retardant standards (eg, EN, DIN, BS) It is necessary to mix a large amount of non-halogen flame retardant. Thereby, there exists a problem that characteristics, such as mechanical strength, a softness | flexibility, heat resistance, and whitening resistance, fall. In particular, in order to obtain electric wires and cables suitable for railway vehicles, development of non-halogen flame retardant resin compositions that can solve the above problems is desired.

  On the other hand, there is a method to reduce the amount of non-halogen flame retardants by adding a flame retardant aid such as red phosphorus, but phosphorous flame retardant aids such as red phosphorus generate harmful phosphine during combustion or phosphorus when discarded. Concerns have been pointed out that it can generate acid and contaminate underground water veins. For this reason, recently, there has been a tendency to refrain from using red phosphorus and the like, and development of a phosphorus-free non-halogen flame-retardant wire / cable excellent in flame retardancy has been required.

  Therefore, the present invention eliminates the problems of the prior art as described above, has high flame retardancy that passes overseas flame retardant standards (standards of any one of EN, DIN, and BS), and An object of the present invention is to provide a phosphorus-free non-halogen flame retardant resin composition which is excellent in mechanical strength, flexibility, heat resistance and whitening resistance and is suitable for railway vehicles, and an electric wire and cable using the same.

  In order to achieve the above object, the present invention provides the following phosphorus-free non-halogen flame retardant resin composition, and electric wires and cables using the same.

[1] A maleic acid-modified ethylene copolymer comprising an ethylene-vinyl acetate copolymer having a vinyl acetate content of 20 to 50% by mass and ethylene and an α-olefin having 3 to 8 carbon atoms as a copolymer component. As a resin component, the content of the ethylene-vinyl acetate copolymer is 50 to 95% by mass in the resin component, and the content of the maleic acid-modified ethylene copolymer is 5 to 5% in the resin component. 30 mass%, and 100 mass parts of the resin component, 100-250 mass parts of fatty acid-treated magnesium hydroxide, 1-15 mass parts of silicone rubber, and 2 carbon black having a surface area of 11-99 m < ² > / g. Phosphorus-free non-halogen flame retardant resin composition characterized by containing ~ 20 parts by mass.
[2] Maleic acid-modified ethylene copolymer comprising an ethylene-vinyl acetate copolymer having a vinyl acetate content of 20 to 50% by mass, and a copolymer component of ethylene and an α-olefin having 3 to 8 carbon atoms. As a resin component, the content of the ethylene-vinyl acetate copolymer is 50 to 95% by mass in the resin component, and the content of the maleic acid-modified ethylene copolymer is 5 to 5% in the resin component. 30 mass%, and 100 mass parts of the resin component, 100-250 mass parts of fatty acid-treated magnesium hydroxide, 1-15 mass parts of silicone rubber, and 2 carbon black having a surface area of 11-99 m < ² > / g. An electric wire comprising an insulating layer made of a phosphorus-free non-halogen flame retardant resin composition containing ˜20 parts by mass.
[3] A maleic acid-modified ethylene copolymer comprising an ethylene-vinyl acetate copolymer having a vinyl acetate content of 20 to 50% by mass and ethylene and an α-olefin having 3 to 8 carbon atoms as a copolymer component. As a resin component, the content of the ethylene-vinyl acetate copolymer is 50 to 95% by mass in the resin component, and the content of the maleic acid-modified ethylene copolymer is 5 to 5% in the resin component. 30 mass%, and 100 mass parts of the resin component, 100-250 mass parts of fatty acid-treated magnesium hydroxide, 1-15 mass parts of silicone rubber, and 2 carbon black having a surface area of 11-99 m < ² > / g. A cable comprising a sheath made of a phosphorus-free non-halogen flame-retardant resin composition containing ˜20 parts by mass.
[4] The cable according to [3], including the electric wire according to [2].

  According to the present invention, it has high flame resistance that passes overseas flame retardant standards (standard of any one of EN, DIN and BS), and has mechanical strength, flexibility, heat resistance and whitening resistance. And a phosphorus-free non-halogen flame retardant resin composition suitable for railway vehicles, and an electric wire and cable using the same.

It is a cross-sectional view which shows typically an example of the electric wire which concerns on embodiment of this invention. It is a cross-sectional view which shows typically an example of the cable which concerns on embodiment of this 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 includes an ethylene-vinyl acetate copolymer having a vinyl acetate content of 20 to 50% by mass, ethylene and α having 3 to 8 carbon atoms. -A maleic acid-modified ethylene copolymer having an olefin as a copolymer component is contained as a resin component, and the content of the ethylene-vinyl acetate copolymer is 50 to 95% by mass in the resin component, The content of the maleic acid-modified ethylene copolymer is 5 to 30% by mass in the resin component, and 100 to 250 parts by mass of fatty acid-treated magnesium hydroxide and 1 to 1 of silicone rubber with respect to 100 parts by mass of the resin component. It is characterized by containing 15 to 20 parts by mass of carbon black having a surface area of 11 to 99 m ² / g.

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

  The ethylene-vinyl acetate copolymer contains vinyl acetate, and when the composition burns and thermally decomposes, it can suppress combustion by causing an endothermic reaction by deacetic acid.

  An ethylene-vinyl acetate copolymer having a VA amount of 20 to 50% by mass is used. Preferably, the amount of VA is 25 to 48% by mass. In order to impart high flame retardancy at the level of vertical combustion test (VFT) or vertical tray combustion test (VTFT), those having a high endothermic vinyl acetate content by deacetic acid reaction during thermal decomposition are preferred. This is because if the amount of VA is less than 20% by mass, the flame retardancy is lowered, and if it exceeds 50% by mass, the mechanical strength (tensile strength) is lowered.

  The content of the ethylene-vinyl acetate copolymer is 50 to 95% by mass in the resin component. Preferably, it is 60-95 mass%.

<Maleic acid-modified ethylene copolymer>
The phosphorus-free non-halogen flame retardant resin composition according to the embodiment of the present invention is a maleic acid-modified ethylene copolymer comprising ethylene as a resin component and an α-olefin having 3 to 8 carbon atoms as a copolymer component. Contains. The maleic acid-modified ethylene copolymer 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.

  The maleic acid-modified ethylene copolymer has a function of improving mechanical strength (tensile strength) and heat resistance by bringing the interface between the ethylene-vinyl acetate copolymer and fatty acid-treated magnesium hydroxide into close contact.

  As the 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 preferable.

  The copolymer is preferably obtained by polymerizing ethylene and an α-olefin having 3 to 8 carbon atoms using a metallocene catalyst. As a result, a high-strength and flexible copolymer having a narrow molecular weight distribution can be obtained.

  Content of the said maleic acid modification ethylene copolymer (for example, maleic acid modification ethylene-butene copolymer) shall be 5-30 mass% in a resin component. Preferably, the content is 5 to 20% by mass. If it is less than 5% by mass, the adhesion between the ethylene-vinyl acetate copolymer and the magnesium hydroxide treated with fatty acid is weak, and sufficient heat resistance cannot be obtained. This is because when the amount exceeds 30% by mass, the adhesion between the ethylene-vinyl acetate copolymer and the fatty acid-treated magnesium hydroxide is strong, and the flexibility is lowered.

<Fatty acid-treated magnesium hydroxide>
In order to improve flame retardancy, the phosphorus-free non-halogen flame retardant resin composition according to the embodiment of the present invention contains 100 to 250 parts by mass of fatty acid-treated magnesium hydroxide with respect to 100 parts by mass of the resin component. To do. Preferably, it contains 130-200 mass parts. If the amount is less than 100 parts by mass, the flame retardancy is insufficient, and if it exceeds 250 parts by mass, the mechanical strength is lowered and the flexibility is also inferior.

<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 containing a large amount of magnesium hydroxide treated with fatty acid tends to cause a whitening phenomenon when the surface is rubbed. This is considered to appear white because a minute gap is generated between the resin and magnesium hydroxide when rubbed, and irregular reflection tends to occur.

  In order not to generate this gap, for example, when silane-treated magnesium hydroxide is used, the adhesion between the resin and the magnesium hydroxide is improved, so that whitening is suppressed to some extent, but flexibility is significantly reduced.

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

  Silicone rubber has the effect of reducing the frictional force, so that the surface of the electric wire becomes slippery when rubbed, and a minute gap between the resin and magnesium hydroxide is less likely to be generated, but it is not sufficient yet.

  Only when the effects of carbon black and silicone rubber are combined, the whitening resistance is improved.

  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 with respect to 100 parts by mass of the resin component. Preferably, it contains 2 to 12 parts by mass. If the amount is less than 1 part by mass, the whitening resistance is insufficient, and if it exceeds 15 parts by mass, slipping occurs in the extruder, making molding difficult.

  The silicone rubber may be a general one such as dimethylsiloxane, methylvinylsiloxane, methylphenylpolysiloxane, and is not particularly limited. These may be used alone or in combination of two or more.

Moreover, 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 with respect to 100 parts by mass of the resin component. . Preferably, it contains 3 to 15 parts by mass. If the amount is less than 2 parts by mass, the whitening resistance is insufficient, and if it exceeds 20 parts by mass, the flexibility decreases.

Carbon black having a surface area of 11 to 99 m ² / g is used. When the surface area is less than 11 m ² / g, the whitening resistance is insufficient, and when the surface area exceeds 99 m ² / g, the flexibility decreases. 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, colorants, ultraviolet absorbers, light stabilizers, crosslinking agents, crosslinking aids. It is possible to add various additives such as an agent.

  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 or a cable sheath of an electric wire. A conventionally known method can be used as the crosslinking method, and there is no particular limitation. 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 made of the phosphorus-free non-halogen flame-retardant resin composition according to the embodiment of the present invention, which is coated on the outer periphery of the conductor. And

FIG. 1 is a cross-sectional view schematically showing an example of an electric wire according to an embodiment of the present invention.
As shown in FIG. 1, the electric wire 10 according to the present embodiment includes a conductor 1 and an insulating layer 2 covered on the outer periphery of the conductor 1. As the conductor 1 to be coated, for example, a conductor having an outer diameter of about 0.15 to 7 mmφ can be used. Although the conductor etc. which twisted the tin plating annealed copper wire can be used conveniently, it is not limited to this. The number of conductors 1 is not limited to one as shown in FIG. 1, and a plurality of conductors may be used.

  The insulating layer 2 is composed of the phosphorus-free non-halogen flame retardant resin composition according to the embodiment of the present invention. It is possible to obtain a phosphorus-free non-halogen flame-retardant electric wire 10 by coating the insulating layer by a molding means such as extrusion coating and then crosslinking the phosphorus-free non-halogen flame-retardant resin composition by a method such as electron beam irradiation. it can. Extrusion coating is a conventionally known electric wire in which a phosphorus-free non-halogen flame retardant resin composition before cross-linking is kneaded with a roll, a banbury, an extruder, etc., and the resulting pellet compound and conductor are provided with a crosshead die. It can be carried out by, for example, wire-coating extrusion with an extruder.

  In the present embodiment, the insulating layer may be a single layer as shown in FIG. 1 or a multilayer structure. Furthermore, you may give a separator, a braiding, etc. as needed.

〔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 showing an example of the cable according to the embodiment of the present invention.
As shown in FIG. 2, the cable 20 according to the present embodiment includes a wire 10 in which a conductor 1 is covered with an insulating layer 2, a two-core stranded wire in which two wires are twisted together with an intervening 3 such as paper, and the outer periphery thereof. And an extrusion-coated sheath 4. Not only a two-core strand wire but one electric wire (single core) may be sufficient, and a multi-core strand wire other than a two-core strand may be sufficient. After the press winding tape is applied to the outer periphery of the two-core stranded wire, the sheath 4 may be extrusion coated on the outer periphery.

  The sheath 4 is comprised from said phosphorus-free non-halogen flame-retardant resin composition which concerns on embodiment of this invention. The insulating layer 2 is not limited to the embodiment composed of the above phosphorus-free non-halogen flame retardant resin composition, and other insulating layer resin compositions (which may be phosphorus-free non-halogen flame retardant). (Preferably). After coating as an insulating layer or a sheath layer by molding means such as extrusion coating, the phosphorus-free non-halogen flame-retardant cable 20 is crosslinked by crosslinking the phosphorus-free non-halogen flame-retardant resin composition by a method such as electron beam irradiation. Can be obtained.

  In the present embodiment, the sheath may be formed of a single layer as shown in FIG. Furthermore, you may give a separator, a braiding, etc. as needed.

  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 shown in FIG. 1 was manufactured by the following method and evaluated.

(1) Production of phosphorus-free non-halogen flame retardant resin composition The materials shown in Tables 1 and 2 were blended in the stated proportions, 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) Production of electric wire On the tin-plated copper stranded wire conductor with a conductor diameter of 2.3 mm, using the 40 mm extruder (L / D = 22) maintained at 100 ° C. with the resin composition produced in (1) above. The film was coated at an extrusion speed of 40 m / min to a thickness of 1.1 mm. Thereafter, crosslinking was performed with 13 kg / cm ² steam for 3 minutes 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 resistance (VTFT) and whitening resistance were evaluated as follows. The evaluation results are shown in Tables 1 and 2.

(Mechanical strength)
The conductor was pulled out from the manufactured electric wire, and the tensile strength and tensile elongation of each sample made into a tube shape were measured by conducting a tensile test according to JIS C3005. The tensile strength was set to 7 MPa or more and the elongation was set to 350% or more. Those above the target value were accepted and those below the target value were rejected.

(Flexibility)
100% modulus was measured in the tensile test. The 100% modulus was targeted at 6 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, then taken out, and the tensile test was performed again to measure the mechanical strength (tensile strength and elongation). , Compared with the initial value (value before the heat aging test). Specifically, tensile strength residual rate (%) = (tensile strength after heat aging test / tensile strength before heat aging test) × 100, elongation residual rate (%) = (elongation after heat aging test) / Elongation before heat aging test) × 100. Both the tensile strength residual rate and the tensile elongation residual rate were targeted to be 80% or more. Those above the target value were accepted and those below the target value were rejected.

(Flame retardance)
For flame retardancy, a vertical tray combustion test (VTFT) was performed in accordance with the BS 6853 standard and BS EN60332 Part 3-21 test method. An electric wire having a total length of 3.5 m was made into one bundle of 7 twists, 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 (one or more standards of EN, DIN, BS), the target carbonization length after self-extinguishing was 2.5 m or less from the lower end. The thing below a target value was set as the pass ((circle)), and the thing exceeding a target value was set as the disqualification (x).

(Whitening resistance)
The whitening resistance was evaluated by visual observation of the whitening resistance when a SUS rod having a diameter of 2 mm was placed on the electric wire and the SUS rod was reciprocated 10 times with a load of 100 g. What did not whiten was set as the pass ((circle)), and what was whitened was set as the disqualification (x).

  In Examples 1 to 10, mechanical strength, flexibility, heat resistance, flame retardancy, and whitening resistance were all good and passed.

On the other hand, in Comparative Example 1, the VA amount of the ethylene-vinyl acetate copolymer exceeds the range specified by the present invention, and the mechanical strength (tensile strength) is inferior.
In Comparative Example 2, the VA amount of the ethylene-vinyl acetate copolymer is less than the range defined by the present invention, and the mechanical strength (elongation), flexibility, and flame retardancy are poor.
In Comparative Example 3, the amount of maleic acid-modified ethylene copolymer added is less (not contained) than the range defined by the present invention, and the heat resistance is poor.
In Comparative Example 4, the amount of maleic acid-modified ethylene copolymer added exceeds the range defined by the present invention, and the flexibility is poor.
In Comparative Example 5, the added amount of fatty acid-treated magnesium hydroxide is less than the range defined by the present invention, and the flame retardancy is poor.
In Comparative Example 6, the added amount of the fatty acid-treated magnesium hydroxide exceeds the range defined by the present invention, and the mechanical strength, flexibility, heat resistance, and whitening resistance are inferior.
In Comparative Example 7, silane-treated magnesium hydroxide not specified in the present invention is added, and the mechanical strength (elongation) and flexibility are inferior.
In Comparative Example 8, the amount of silicone rubber added is less (not contained) than the range defined by the present invention, and the whitening resistance is poor.
In Comparative Example 9, the amount of silicone rubber added exceeds the range specified by the present invention, and extrusion molding cannot be performed.
In Comparative Example 10, the amount of carbon black added exceeds the range defined by the present invention, and the mechanical strength (elongation) and flexibility are inferior.
In Comparative Example 11, the surface area of carbon black is smaller than the range defined by the present invention, and the whitening resistance is poor.
In Comparative Example 12, the surface area of carbon black is larger than the range defined by the present invention, and the mechanical strength (elongation) and flexibility are inferior.

  In addition, this invention is not limited to the said embodiment and Example, A various deformation | transformation implementation is possible.

1: Conductor, 2: Insulating layer, 3: Intervening, 4: Sheath 10: Electric wire, 20: Cable

Claims (4)

Resin comprising an ethylene-vinyl acetate copolymer having a vinyl acetate content of 20 to 50% by mass and a maleic acid-modified ethylene copolymer containing ethylene and an α-olefin having 3 to 8 carbon atoms as a copolymer component Contained as an ingredient,
The content of the ethylene-vinyl acetate copolymer is 50 to 95% by mass in the resin component, and the content of the maleic acid-modified ethylene copolymer 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 20 parts by mass of carbon black having a surface area of 11 to 99 m ² / g with respect to 100 parts by mass of the resin component A phosphorus-free non-halogen flame retardant resin composition characterized by the above. Resin comprising an ethylene-vinyl acetate copolymer having a vinyl acetate content of 20 to 50% by mass and a maleic acid-modified ethylene copolymer containing ethylene and an α-olefin having 3 to 8 carbon atoms as a copolymer component The content of the ethylene-vinyl acetate copolymer is 50 to 95% by mass in the resin component, and the content of the maleic acid-modified ethylene copolymer 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 20 parts by mass of carbon black having a surface area of 11 to 99 m ² / g with respect to 100 parts by mass of the resin component. An electric wire comprising an insulating layer made of a phosphorus-free non-halogen flame-retardant resin composition containing a part thereof. Resin comprising an ethylene-vinyl acetate copolymer having a vinyl acetate content of 20 to 50% by mass and a maleic acid-modified ethylene copolymer containing ethylene and an α-olefin having 3 to 8 carbon atoms as a copolymer component The content of the ethylene-vinyl acetate copolymer is 50 to 95% by mass in the resin component, and the content of the maleic acid-modified ethylene copolymer 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 20 parts by mass of carbon black having a surface area of 11 to 99 m ² / g with respect to 100 parts by mass of the resin component. A cable comprising a sheath made of a phosphorus-free non-halogen flame-retardant resin composition containing a part thereof.   The cable according to claim 3, comprising the electric wire according to claim 2.

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