JP5269476B2 - Electric wire / cable - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a halogen-free flame-retardant polyolefin composition having good flexibility and terminal processability and excellent also in mechanical strength, and an electric wire and cable using the same. <P>SOLUTION: The flame-retardant polyolefin composition contains (A) 100 pts.mass of a polyolefin comprising (a-1) 50-80 mass% of an ethylene-propylene-diene copolymer, (a-2) 10-25 mass% of an ethylene-vinyl acetate copolymer and (a-3) 10-25 mass% of a liner polyethylene, (B) 50-120 pts.mass of a metal hydroxide and (C) 3-20 pts.mass of carbon black. The electric wire and cable have a coating 2 comprising such a flame-retardant polyolefin composition. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a halogen-free flame-retardant polyolefin composition useful as an insulating material for an in-panel wiring electric wire or a lead-out electric wire, and an electric wire / cable using the same.

  Conventionally, electric wires using chlorosulfonated polyethylene as an insulating material have been widely used for wiring in panels and lead wires of electrical equipment because they are flexible and have excellent handling properties and good flame retardancy. .

  With the recent increase in awareness of global environmental protection, flame retardant by adding a large amount of metal hydroxide such as aluminum hydroxide or magnesium hydroxide to polyolefin instead of halogen-containing materials such as chlorosulfonated polyethylene Electric wires using halogen-free insulating materials have been used. This is because halogen-containing materials generate harmful gases such as hydrogen halide and a large amount of smoke during combustion.

  However, the electric wire using the halogen-free insulating material has poor flexibility as compared with the electric wire using the conventional chlorosulfonated polyethylene, and a jig such as a wire stripper is used for terminal processing. When the insulator is peeled off, there is a problem that the insulator extends and remains in a whisker shape. The poor flexibility is due to the addition of a large amount of metal hydroxide to impart flame retardancy, and the beard is formed on the end face of the insulator during terminal processing. This is because the growth of is large.

  In order to solve such a problem, for example, measures such as using a flexible base polymer or preventing the whisker from being formed when the insulator is peeled off as a multilayer structure can be considered. The mechanical strength of the latter is lowered, and in the latter case, the flexibility is lowered.

On the other hand, various techniques for improving the physical properties of halogen-free flame retardant compositions used for electric wires and cables have been proposed (see, for example, Patent Document 1). However, a halogen-free flame retardant composition having improved flexibility and terminal processability without reducing mechanical strength has not yet been obtained.
Special table 2007-512426 gazette

  The present invention has been made to solve the above-described problems of the prior art, and is useful as an insulating material for an in-panel wiring electric wire or a lead-out electric wire. An object of the present invention is to provide a halogen-free flame-retardant polyolefin composition having excellent mechanical strength, and an electric wire / cable using the same.

In order to achieve the above object, the invention described in claim 1 includes (A) (a-1) ethylene / propylene / diene copolymer 50 to 80% by mass, (a-2) vinyl acetate content 30 % by mass. %, Melt flow rate (JIS K 7210; 190 ° C., load 2160 g) 1 g / 10 min or less, 10-25% by mass of ethylene / vinyl acetate copolymer , and (a-3) density synthesized by metallocene catalyst Less than 0.890 g / cm ³ , tensile fracture strength (JIS K 7113) 30 MPa or more, flexural rigidity (ASTM D 747) 15 MPa or less, 100 mass parts of polyolefin composed of 10-25 mass% linear low density polyethylene in contrast, (B) magnesium hydroxide and / or aluminum hydroxide 50 to 120 parts by weight, and (C) a carbon black 3-20 parts by weight including A wire or cable characterized in that it comprises a coating of the flame-retardant polyolefin composition.

Invention described in claim 2 is the wire or cable of claim 1, the tensile strength (JIS K 7113) is a wire or cable is at least 10 MPa.

A third aspect of the present invention is the electric wire / cable according to the first or second aspect , wherein the electric wire / cable is used as an in-panel wiring or a lead wire.

  According to the flame-retardant polyolefin composition of the present invention, it is halogen-free and can have both good flexibility and terminal processability and sufficient mechanical strength. Further, according to the electric wire / cable of the present invention, it is possible to obtain an electric wire / cable having both halogen-free flame retardancy, good flexibility and terminal processability, and sufficient mechanical strength.

  Embodiments of the present invention will be described below.

  First, the flame retardant polyolefin composition of the present invention will be described.

  The (A) polyolefin used as the base polymer of the flame retardant polyolefin composition of the present invention includes (a-1) an ethylene / propylene / diene copolymer (hereinafter referred to as EPDM) and (a-2) an ethylene / vinyl acetate. Copolymers (hereinafter EVA) and (a-3) linear low density polyethylene (hereinafter LLDPE).

The EPDM of the component (a-1) is not particularly limited, but from the viewpoint of a balance between physical properties and processability, the EPDM has an ethylene content of 60 to 70 mol% and an iodine value of 10 to 15. preferable. Moreover, as EVA of (a-2) component, from the viewpoint of balancing flexibility and tensile strength, the vinyl acetate (hereinafter referred to as VA) content is 30% by mass or more and the melt flow rate (hereinafter referred to as MFR). (JIS K 7210; 190 ° C., load 2160 g) is preferably 1 g / 10 min or less, VA content is 30 to 40% by mass, and MFR is in the range of 0.5 to 1 g / 10 min. More preferred. Furthermore, as the LLDPE of the component (a-3), as in the case of EVA, from the viewpoint of balancing flexibility and tensile strength, the density synthesized by the metallocene catalyst is less than 0.890 g / cm ³ , and tensile fracture strength It is preferable that the thickness (JIS K 7113) is 30 MPa or more and the flexural rigidity (ASTM D 747) is 15 MPa or less. In this case, the comonomer component copolymerized with ethylene includes α-olefins such as propylene, butene, pentene, hexene, octene, and hexene is particularly preferable.

  In the present invention, (A) the composition of the above three components of polyolefin is (a-1) EPDM 50-80% by mass, (a-2) EVA 10-25% by mass, (a-3) LLDPE 10-25% by mass. And By setting it as such a compounding composition, it can be set as the flame-retardant polyolefin composition which has a favorable softness | flexibility, terminal processability, and mechanical strength, having a halogen-free flame retardance.

  That is, if the blending amount of EPDM as the component (a-1) is less than 50% by mass, the terminal processability is poor, and conversely if it exceeds 80% by mass, the tensile strength is lowered. On the other hand, if the amount of the EVA component (a-2) is less than 10% by mass, the flame retardancy is poor, whereas if it exceeds 25% by mass, the terminal processability is degraded. Furthermore, if the blending amount of the LLDPE as the component (a-3) is less than 10% by mass, the tensile strength becomes poor, and conversely if it exceeds 25% by mass, the terminal processability is lowered. (A) Polyolefin preferably has a composition of (a-1) 60 to 70% by mass of EPDM, (a-2) 15 to 20% by mass of EVA, and (a-3) 15 to 20% by mass of LLDPE.

  The metal hydroxide of the component (B) of the flame retardant polyolefin composition of the present invention releases water when exposed to a high temperature, and suppresses the temperature rise by the heat of vaporization at that time to exhibit a flame retardant effect. Examples thereof include magnesium hydroxide, aluminum hydroxide, calcium hydroxide and the like. These may be used individually by 1 type, and may mix and use 2 or more types. As the metal hydroxide of the component (B), magnesium hydroxide and aluminum hydroxide are particularly preferable from the viewpoint of balance between flame retardancy and physical properties. The metal hydroxide may have been subjected to surface treatment with a higher fatty acid such as stearic acid or a silane coupling agent. By using such a surface-treated metal hydroxide, the dispersibility when kneading with the base polymer can be enhanced. Examples of commercially available products that are preferably used as the metal hydroxide of component (B) include Kisuma 5A and Kisuma 5L manufactured by Kyowa Chemical Industry Co., Ltd. ) And the like.

  The compounding quantity of the metal hydroxide of this (B) component is 50-120 mass parts with respect to 100 mass parts of total amounts of (A) component, Preferably it is 60-100 mass parts. When the blending amount is less than 50 parts by mass, the flame retardancy becomes insufficient, and when it exceeds 120 parts by mass, the flexibility becomes poor.

  The carbon black of the component (C) of the flame retardant polyolefin composition of the present invention is a component that acts as a flame retardant aid and a reinforcing agent. Examples of commercially available products include, for example, Seast 116 manufactured by Tokai Carbon Co., Ltd., Asahi Carbon Asahi # 60H, Asahi # 60HN manufactured by the company, Diablack N550M (trade name) manufactured by Mitsubishi Chemical Corporation, and the like.

The compounding amount of the carbon black of the component (C) is 3 to 20 parts by mass, preferably 5 to 10 parts by mass with respect to 100 parts by mass of the total amount of the component (A). When the blending amount is less than 3 parts by mass,
Flame retardancy becomes insufficient, and conversely, if it exceeds 20 parts by mass, flexibility becomes poor.

  In the flame-retardant polyolefin composition of the present invention, it is preferable to crosslink the polymer component after coating or molding, whereby heat resistance and mechanical properties can be improved. As the crosslinking method, a crosslinking agent may be added to the flame retardant polyolefin composition in advance, and a chemical crosslinking method in which crosslinking is performed after molding, an electron beam crosslinking method by electron beam irradiation, or the like can be used. From such viewpoints, a chemical crosslinking method is preferable, and a method of crosslinking with an organic peroxide is particularly preferable.

  Examples of the organic peroxide used include 1,3-bis (tert-butylperoxyisopropyl) benzene, dicumyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di- ( tert-butylperoxy) hexane, 2,5-dimethyl-2,5-di- (tert-butylperoxy) hexyne-3, 1,3-bis (tert-butylperoxyisopropyl) benzene, 1,1-bis (tert- Butylperoxy) -3,3,5-trimethylcyclohexane, n-butyl-4,4-bis (tert-butylperoxy) valerate, benzoyl oxide, 2,4-dichlorobenzoyl peroxide, tert-butylperoxybenzoate, tert- Butyl peroxyisopropyl carbonate Diacetyl peroxide, lauroyl peroxide, etc. tert- butyl cumyl peroxide and the like.

  In addition to the components described above, the flame retardant polyolefin composition of the present invention may further include a lubricant, an antioxidant, an antioxidant, an ultraviolet absorber, as long as the effect of the present invention is not impaired. Light stabilizers, fillers, reinforcing agents, plasticizers, softeners, processing aids, crosslinking aids, antistatic agents, flame retardants other than metal hydroxides, and other additives can be blended.

  The flame-retardant polyolefin composition of the present invention preferably has a tensile strength (JIS K 7113) of 10 MPa or more, and more preferably 11 MPa or more. If the tensile strength (JIS K 7113) is less than 10 MPa, the mechanical strength becomes insufficient, making it difficult to apply as an insulating material or covering material for electric wires and cables used for wiring in the panel and lead wires. Become.

  In the flame-retardant polyolefin composition of the present invention, the above-described components (A) to (C) and the components to be blended as necessary are usually kneaded such as a Banbury mixer, a pressure kneader, a kneading extruder, and a mixing roll. It can be easily produced by uniformly kneading using a machine.

  Moreover, the electric wire and cable of this invention are manufactured by extrusion-coating the composition obtained in this way to the conductor outer periphery directly or through another coating. As described above, the composition is preferably crosslinked after coating.

  The insulating resin composition of the present invention includes, for example, various insulated wires such as in-panel wiring wires and lead wire wires, power cables, cables for high voltage electronic devices, control cables, communication cables, instrument cables, signal cables. It can be widely used for applications such as insulation materials and sheath materials for various cables such as moving cables, and accessories for electric wires and cables such as plugs. In particular, the flame-retardant polyolefin composition of the present invention has good flexibility and terminal processability, and is excellent in mechanical strength, so it is useful as an insulating material for wires for in-panel wiring and lead wires. It is.

  FIG. 1 is a cross-sectional view showing an embodiment of the electric wire / cable of the present invention.

In FIG. 1, 1 indicates a copper conductor having a cross-sectional area of 5.5 mm ² , for example. On the copper conductor 1, the above-mentioned flame retardant polyolefin composition is extrusion-coated and then crosslinked, for example, to have a thickness. An insulator 2 having a thickness of 1 mm is formed.

  Insulated electric wires configured in this manner have halogen-free flame retardancy, and are excellent in environmental conservation without generating harmful gases or a large amount of smoke during combustion. In addition, the flexibility is good, the insulator does not expand like a whisker during terminal processing, and it has sufficient mechanical strength.

  EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples at all.

Examples 1-7 , Reference Examples 1-2 , Comparative Examples 1-9
EPDM, EVA and LLDPE shown below, magnesium hydroxide surface-treated with a fatty acid as a metal hydroxide (trade name Kisuma 5A, manufactured by Kyowa Chemical Industry Co., Ltd.), aluminum hydroxide (trade name, Hydylite H42M, manufactured by Showa Denko KK), carbon Black (Tokai Carbon Co., Ltd., trade name: Seast 116) and 1,3-bis (tert-butylperoxyisopropyl) benzene as an organic peroxide, each component being biaxially mixed at the blending ratios shown in Tables 1 and 2 A compound was obtained by uniformly kneading with an extruder, and this was extrusion-coated on a copper conductor having a cross-sectional area of 5.5 mm ^{2 to} a thickness of 1 mm, and crosslinked by a conventional method to produce an insulated wire.
EPDM: Mooney viscosity ML _{1 + 4} 100 ° C. 38, ethylene content 68 mol%,
DCPD (dicyclopentadiene) content 6.2% by mass, iodine value 12
EVA (1): MFR 0.5 g / 10 min, VA content 33% by mass
Density 0.960 g / cm ³
EVA (2): MFR 2.5 g / 10 min, VA content 46% by mass
Density 0.980 g / cm ³
LLDPE (1): synthesized by metallocene catalyst (using hexene as comonomer),
Density 0.880 g / cm ³ , tensile fracture strength 32 MPa,
Bending rigidity 11MPa
LLDPE (2): synthesized by metallocene catalyst (using hexene as comonomer),
Density 0.898 g / cm ³ , tensile fracture strength 52 MPa,
Flexural rigidity 50 MPa

Various characteristics were evaluated by the method shown below about the obtained insulated wire.
[Tensile strength]
It measured based on JISC3005.
[Flexibility]
One end (length 50 mm) of a 150 mm long wire sample was fixed to a horizontal plane, and the amount of deflection (mm) of the sample (length 100 mm) when a weight with a mass of 100 g was hung on the other end was measured.
[Terminal processability]
The insulator was peeled off with a wire stripper, and the length of the beard-like portion remaining on the end face was measured.
[Flame retardance]
When the 60 degree inclined combustion test specified in JIS C 3005 is conducted and the fire extinguishes spontaneously within 60 seconds after ignition, it passes (○). It was determined to be rejected (x).

  These evaluation results are shown in the lower column of Tables 1 and 2.

As is apparent from Table 1, all of the insulated wires obtained in the examples have a sufficient mechanical strength with a tensile strength of 10 MPa or more, and the flexibility is good with a deflection amount of 50 mm or more. Met. Furthermore, terminal processability and flame retardancy were also good. Particularly, EVA satisfying the conditions that the vinyl acetate content is 30% by mass or more and the MFR (JIS K 7210; 190 ° C., load 2160 g) is 1 g / 10 min or less is used, and the metallocene is used as the LLDPE. Examples 1 to 6 using a catalyst that satisfies the conditions that the density is less than 0.890 g / cm ³ , the tensile fracture strength (JIS K 7113) is 30 MPa or more, and the flexural rigidity is 15 MPa or less. Thus, the balance between mechanical strength and flexibility was better.

  On the other hand, in the comparative example, the tensile strength, flexibility, terminal workability and flame retardance are all good as in Comparative Example 1 which is excellent in tensile strength, flexibility and terminal workability but poor in flame retardancy. There was nothing that was.

It is a cross-sectional view which shows one Embodiment of the electric wire and cable of this invention.

Explanation of symbols

  1 ... copper conductor, 2 ... insulator.

Claims (3)

(A) (a-1) ethylene / propylene / diene copolymer 50 to 80% by mass, (a-2) vinyl acetate content 30% by mass or more, melt flow rate (JIS K 7210; 190 ° C., load 2160 g) 10 to 25% by mass of ethylene / vinyl acetate copolymer of 1 g / 10 min or less , and (a-3) Density less than 0.890 g / cm ³ synthesized by metallocene catalyst , tensile fracture strength (JIS K 7113) (B) Magnesium hydroxide and / or aluminum hydroxide 50 to 100 parts by mass of polyolefin consisting of 10 to 25% by mass of linear low-density polyethylene having a bending rigidity (ASTM D 747) of 15 MPa or less. having 120 parts by weight, and (C) coating of carbon black flame retardant polyolefin compositions containing from 3 to 20 parts by weight Wires and cables, characterized and. The electric wire / cable according to claim 1, wherein the flame-retardant polyolefin composition has a tensile strength (JIS K 7113) of 10 MPa or more. The electric wire / cable according to claim 1 or 2 , wherein the electric wire / cable is used as in-panel wiring or lead wire.

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