JP2003132741A - Insulated electric wire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance low temperature resistance, and anti-wound property in an insulated electric wire having an insulator made of a non halogen flame- resisting resin composition having a high flame resistance by composing a large quantity of magnesium hydroxide, flame resisting agent to an ethylenic copolymer such as EVA, EEA or the like. SOLUTION: The insulator is constituted of layers of 2 layers or more, and the outmost layer is constituted of anti-wound property composition, for example the resin composition A containing ionomer or ethylene-methacrylic acid copolymer 100 parts by weight, magnesium hydroxide 300 parts by weight or less, and flame resisting agent 20 parts by weight or less, and its innermost layer is constituted of flame-resisting resin composition B comprised that magnesium hydroxide 40 to 200 parts by weight and flame resisting agent 1 to 20 parts by weight is blended against the base polymer 10 parts by weight composed of ethylenic copolymer 40 to 90 parts by weight, ethylene-acrylic elastomer 5 to 50 parts by weight, and ionomer or ethylene-methacrylic acid copolymer 0.5 to 50 parts by weight.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an insulated wire having an insulator made of a halogen-free flame-retardant resin composition, and in particular, has improved cold resistance and external damage resistance.

[0002]

2. Description of the Related Art Conventionally, a halogen-free flame-retardant resin composition which does not generate a combustion gas such as a halogen gas which is harmful when burned has been developed and put to practical use as a coating material for an insulator such as an electric wire or a cable. There is. As such a halogen-free flame-retardant resin composition, an ethylene-based copolymer such as an ethylene-vinyl acetate copolymer or an ethylene-ethyl acrylate copolymer is used as a base polymer, and 100 parts by weight of this base polymer is used as a flame retardant. It is known that 50 to 200 parts by weight of magnesium hydroxide is blended and, if necessary, 2 to 20 parts by weight of a silicone compound or the like as a flame retardant aid is blended.

In the halogen-free flame-retardant resin composition having this composition, magnesium hydroxide has a relatively high flame-retardancy-providing effect as compared with other metal hydroxides such as aluminum hydroxide. It has the advantages that it exhibits excellent flame retardancy, does not generate harmful halogen gas during combustion, and does not elute heavy metals and phosphorus compounds.

However, in order to obtain higher flame retardancy, (1) if a large amount of magnesium hydroxide is blended,
The amount of magnesium hydroxide particles dispersed in the resin tends to increase, and the mechanical properties of the resin composition tend to deteriorate.
(2) Similarly, in order to obtain high flame retardancy, if the ethylene-based copolymer is a large-polarity copolymerized with a large amount of polarities such as vinyl acetate groups and ethyl acrylate groups,
The rigidity of the composition is lowered, and due to these factors, the cold resistance and the external damage resistance are greatly lowered.

[0005]

Therefore, the object of the present invention is to solve the problems of ethylene-vinyl acetate copolymer, ethylene-
In an insulated wire having an insulator composed of a halogen-free flame-retardant resin composition having high flame retardancy, which is obtained by blending a large amount of magnesium hydroxide with an ethylene-based copolymer such as an ethyl acrylate copolymer, a flame retardant aid, It is to improve cold resistance and trauma resistance.

[0006]

In order to solve the above problems, the invention of claim 1 is characterized in that the insulator is composed of two or more layers, and the outermost layer is composed of a trauma resistant composition. It is an insulated wire. According to a second aspect of the present invention, the insulator is composed of two or more layers, and the outermost layer is an ionomer or ethylene-methacrylic acid copolymer 100 parts by weight, magnesium hydroxide 300 parts by weight or less, and flame retardant aid 20 parts by weight. From the resin composition A containing the following, the innermost layer thereof is composed of 40 to 90 parts by weight of an ethylene copolymer and 5 to 5 of ethylene acrylic rubber.
40 parts by weight of magnesium hydroxide based on 100 parts by weight of a base polymer consisting of 0 parts by weight and 0.5 to 50 parts by weight of an ionomer or an ethylene-methacrylic acid copolymer.
The insulated wire is composed of a flame-retardant resin composition B containing 0 part by weight and 1 to 20 parts by weight of a flame-retardant aid.

The invention according to claim 3 is the insulated wire according to claim 2, wherein 50 wt% or more of magnesium hydroxide contained in the outermost layer and the innermost layer is surface-treated with a silane coupling agent. In the invention of claim 4, the thickness of the insulator is 1 mm or less, and the thickness of the outermost layer is 0.05 to 0.4 m.
The insulated wire according to claim 1 or 2, wherein m is m. The invention of claim 5 is the insulated wire according to claim 1 or 2, wherein the insulator is irradiated with an electron beam to be crosslinked.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will now be described in detail based on the embodiments of the invention. In the insulated wire of the present invention, the insulator is composed of at least two layers, and the outermost layer thereof is composed of the scratch-resistant resin composition. In the present invention, the term “trauma-resistant resin composition” means that the insulating surface of an insulated wire having an insulator made of this resin composition is N
This is a resin composition that shows a shaving of a depth of 0.05 mm or less when scratched 10 times with an EMA type abrasion tester (cylindrical diameter of needle: 0.8 mm).

Specific examples of such a trauma resistant resin composition include 100 parts by weight of an ionomer or ethylene-methacrylic acid copolymer, and 300 parts of magnesium hydroxide.
The resin composition A containing 20 parts by weight or less of the flame retardant auxiliary agent is included.

The ionomer here is ethylene-
An α, β-unsaturated carboxylic acid copolymer is used as a base, and all or part of its carboxyl group, usually 5 to 90 mol%, is neutralized with a metal ion such as an alkali metal or an alkaline earth metal to form an intermolecular structure. Is a cross-linked product.

The proportion of ethylene units in this ethylene-α, β-unsaturated carboxylic acid copolymer is usually 75 to 99.5 mol%, preferably 88 to 98 mol%, and α, β-unsaturated The ratio of the saturated carboxylic acid unit is
It is 0.5 to 15 mol%, preferably 1 to 6 mol%.

The proportion (neutralization degree) of the carboxyl groups in the ethylene-α, β-unsaturated carboxylic acid copolymer, which are neutralized by metal ions, is usually 5 to 90 mol%. In order to obtain a composition excellent in mechanical properties and the like, it is preferable to use a composition of 40 to 90 mol%.
This ionomer is a polymer that is tough, has high mechanical strength, and is excellent in abrasion resistance and external damage resistance.

Further, as the ethylene-methacrylic acid copolymer used in the resin composition A, a copolymer of ethylene and 0.01 to 40 mol% of methacrylic acid is used. This ethylene-methacrylic acid copolymer, like the ionomer, is a polymer that is tough, has high mechanical strength, and is excellent in abrasion resistance and scratch resistance. This ethylene-methacrylic acid copolymer is one type of ethylene-based copolymer, but in the present invention, it is to be distinguished from other ethylene-based copolymers.

As the magnesium hydroxide used in the resin composition A, one having an average particle size of 0.1 to 10 μm is used, and 50% by weight or more of the total amount thereof has an affinity for the ionomer or the ethylene-methacrylic acid copolymer. In order to improve the properties, it is preferable that the surface treatment is performed using a titanate coupling agent, a silane coupling agent such as vinylsilane, epoxysilane, or aminosilane, a higher fatty acid such as stearic acid, oleic acid, or lauric acid. .

The amount of magnesium hydroxide added to the ionomer or ethylene-methacrylic acid copolymer is 300 parts by weight or less, preferably 200 parts by weight or less, relative to 100 parts by weight of the ionomer or ethylene-methacrylic acid copolymer. To be done. If the amount of magnesium hydroxide added exceeds 300 parts by weight, the mechanical properties of the outermost layer of the insulator, particularly the elongation, will be insufficient. Therefore,
The amount of magnesium hydroxide added is preferably the minimum necessary, especially when high flame retardancy is not required,
It is not necessary to add it.

A flame retardant aid is added to the resin composition A to reduce the compounding amount of magnesium hydroxide so as to prevent the mechanical properties and processability of the composition from deteriorating. Examples of the flame retardant aid include silicone compounds such as silicone powder and silicone gum, phosphorus compounds such as red phosphorus and ammonium polyphosphate, molybdenum compounds such as zinc molybdate, zinc oxide, zinc hydroxystannate, and zinc stannate. Zinc compounds such as zinc borate and nitrogen-containing compounds such as melamine cyanurate are used.

The amount of the flame retardant auxiliary compounded is within the range of 20 parts by weight or less with respect to 100 parts by weight of the ionomer or ethylene-methacrylic acid copolymer, and the required degree of flame retardancy is mainly obtained from the flame retardant auxiliary agent. It can be determined by taking into consideration the type, the amount of magnesium hydroxide, etc., but if it exceeds 20 parts by weight, the mechanical properties of the outermost layer will deteriorate. Good. For this reason,
This resin composition A is not necessarily flame retardant.

As the resin composition A forming the outermost layer of the insulator, other than this, a small amount of another olefin silicopolymer such as polypropylene acid-modified with maleic anhydride or high-density polyethylene can be added, and the resin composition is aged. An appropriate amount of additives such as an inhibitor, an ultraviolet absorber, a colorant, and carbon black may be added.

Further, in this resin composition A, the ethylene graft copolymer is added in an amount of 0.05 to 10 with respect to 100 parts by weight of the ionomer or ethylene-methacrylic acid copolymer.
It may be added in an amount of part by weight to enhance printability when the outermost layer of the insulator is formed. This ethylene graft copolymer was obtained by graft-copolymerizing an ethylene-based copolymer with any of acrylonitrile-styrene, styrene, methyl methacrylate and methyl acrylate monomers to form a branch of a polymer composed of these monomers. It is a thing.

The content of the graft copolymerized branched polymer in this graft ethylene copolymer is 10 to 5
It is preferably 0 wt% because printability is improved. The addition of this graft ethylene copolymer enhances the printability of the composition due to the presence of the graft copolymerized branched polymer. In particular, the effect is remarkable when a printing ink using an ester solvent such as ethyl acetate or butyl acetate or a ketone solvent such as methyl ethyl ketone or methyl isobutyl ketone is used as the printing ink.

The flame-retardant resin composition B, which forms the innermost layer of the insulator of the insulated wire, contains 40 to 90 parts by weight of an ethylene copolymer, 5 to 50 parts by weight of ethylene acrylic rubber, and an ionomer or ethylene. Methacrylic acid copolymer 0.5
-100 to 50 parts by weight of the base polymer, 40 to 200 parts by weight of magnesium hydroxide and 1 to 20 parts by weight of the flame retardant aid are blended.

The ethylene-based copolymer which is the first component of the base polymer of the flame-retardant resin composition B includes ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer and ethylene-methyl methacrylate. One or a mixture of two or more copolymers of ethylene and a monomer containing oxygen in the molecule such as a copolymer and an ethylene-acrylic acid copolymer is used. Among these ethylene-based copolymers, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer and the like are preferable because they have high affinity with magnesium hydroxide and good flame retardancy. This ethylene-based copolymer includes the above ionomer,
The ethylene-methacrylic acid copolymer and the below-mentioned ethylene acrylic rubber are not included.

As the ethylene-vinyl acetate copolymer,
A vinyl acetate content of 15 to 50 wt% and a melt flow rate (190 ° C., 2.16 kg, 10 minutes, and so on) of 0.01 to 10 are preferable. The ethylene-ethyl acrylate copolymer has an ethyl acrylate content of 15 to 50 wt% and a melt flow rate of 0.01.
Those of 10 are preferable.

The ethylene acrylic rubber which is the second component of the base polymer is a binary copolymer of ethylene and an alkyl acrylate such as ethyl acrylate or methyl acrylate, or ethylene and ethyl acrylate, or acrylic acid. A rubber elastic body made of a terpolymer of an alkyl acrylate such as methyl and an acrylic acid ester-based polyfunctional monomer is used.

The ethylene content of this ethylene acrylic rubber is 30 to 70 wt%. The blending of such an ethylene acrylic rubber enhances the flame retardancy of the flame-retardant resin composition B to be obtained, whereby the blending amount of magnesium hydroxide and a flame retardant aid is reduced while maintaining high flame retardancy. It becomes possible. Further, the same ionomer or ethylene-methacrylic acid copolymer as the third component of the base polymer is the same as that used in the resin composition A described above.

The mixing ratio of each component in this base polymer is such that the total amount of the base polymer is 100 parts by weight.
The ethylene copolymer is 40 to 90 parts by weight, the ethylene acrylic rubber is 5 to 50 parts by weight, and the ionomer or ethylene-methacrylic acid copolymer is 0.05 to 40 parts by weight. If the amount of the ethylene-based copolymer is less than 40 parts by weight, the tackiness is large and it becomes difficult to process, and if it exceeds 90 parts by weight, the flame retardancy is lowered. If the amount of ethylene acrylic rubber is less than 5 parts by weight, the flame retardancy is insufficient, and if it exceeds 50 parts by weight, the tackiness is large and processing becomes difficult. When the amount of the ionomer or ethylene-methacrylic acid copolymer is less than 0.05 parts by weight, there is no effect of improving cold resistance and trauma resistance, and when it exceeds 40 parts by weight, these effects are saturated and the cost becomes high and the elongation decreases. To do.

The flame retardant resin composition B contains magnesium hydroxide as a flame retardant and a flame retardant aid. As the magnesium hydroxide, it is preferable to use the one whose surface is treated with at least 50% by weight or more of the used amount as described above. The amount of this magnesium hydroxide added to the base polymer is 40 to 200 parts by weight, preferably 50 to 200 parts by weight, based on 100 parts by weight of the base polymer.
It is set in the range of 150 parts by weight and is determined according to the required flame retardancy, but if it is less than 40 parts by weight, the improvement of the flame retardancy cannot be obtained sufficiently, and if it exceeds 200 parts by weight, the mechanical properties deteriorate.

As the flame retardant aid in the flame-retardant resin composition B, silicone powder, silicone compounds such as silicone gum, red phosphorus, phosphorus compounds such as ammonium polyphosphate, molybdenum, etc. are used as in the above. Molybdenum compounds such as zinc acid, zinc oxide, zinc hydroxystannate, zinc stannate, zinc compounds such as zinc borate, and nitrogen-containing compounds such as melamine cyanurate are used.

The blending amount of this flame retardant aid is in the range of 1 to 20 parts by weight with respect to 100 parts by weight of the base polymer. It can be decided by taking into account the amount of compounding.

If necessary, a processing aid such as stearic acid or calcium stearate for improving processability is added to the resin compositions A and B in an amount of about 0.5 to 5 parts by weight per 100 parts by weight of the base polymer. be able to.
Further, an appropriate amount of additives such as an antiaging agent, a colorant, a copper damage inhibitor, and carbon black can be added.

The insulated wire of the present invention comprises two or more layers, the outermost layer of which is a trauma-resistant resin composition, specifically the resin composition A described above, and the innermost layer of which is a flame-retardant resin composition B. It has an insulator made of. The insulator is formed by a usual extrusion coating method. After coating the outermost layer, the innermost layer may be coated. If the insulator has two layers, it may be coated by the two-layer simultaneous coating method. good. When the insulating material has three or more layers, the intermediate layer is not particularly limited, but is preferably made of a non-halogen polyolefin polymer.

The total thickness of this insulator is set to 1 mm or less so that the inside can be sufficiently cross-linked when irradiated with an electron beam.
If it exceeds 1 mm, electron beam crosslinking becomes insufficient inside. The thickness of the outermost layer is 0.05 to 0.4 mm. If the thickness of the outermost layer is less than 0.05 mm, the scratch resistance is insufficient, and if it exceeds 0.4 mm, the flexibility as an electric wire is insufficient and the flame retardancy is also insufficient.

Further, the insulated wire may be irradiated with an electron beam to crosslink each resin composition forming an insulator to improve heat resistance and mechanical properties. Electron beam crosslinking is preferable because crosslinking can be performed at a higher speed than chemical crosslinking. The electron beam irradiation condition is 0.5 to
It is set to 20 Mrad. The gel fraction of the resin component due to this crosslinking is preferably 30 to 75%, and if it is less than 30%, the heat resistance is insufficient, and the heat deformation test fails, resulting in 75%.
If it exceeds, the elongation will be 100% or less and the elongation will be insufficient.

In such an insulated electric wire, the insulator is composed of at least two layers, and the outermost layer thereof is a scratch resistance of a resin composition A or the like having an ionomer or an ethylene-methacrylic acid copolymer as a base polymer. As it consists of a resin composition, the outermost layer is tough, flexible, impact resistant,
It is highly resistant to trauma. Further, in the case of using the base polymer blended with the ethylene graft copolymer, in addition to this, the printability of the outermost layer becomes high. Further, in the case of containing magnesium hydroxide and a flame retardant aid, the outermost layer has high flame retardancy.

A flame-retardant resin composition B in which magnesium hydroxide and a flame-retardant auxiliary agent are mixed with a base polymer composed of an ethylene-based copolymer, ethylene acrylic rubber and an ionomer for the innermost layer of the insulator. Since it is composed of, the innermost layer has high flame retardancy, cold resistance, and mechanical properties.

That is, since ethylene acrylic rubber is used, and magnesium hydroxide and a flame retardant auxiliary are used in combination, the flame retardancy is enhanced, and the ethylene acrylic rubber has good elasticity at low temperatures, which improves cold resistance. To be The ethylene-based copolymer has good compatibility with magnesium hydroxide, and by adopting surface-treated magnesium hydroxide, even if a large amount of magnesium hydroxide is blended, mechanical properties are not deteriorated, and UL standard VW- Achieve a flame retardancy level of 1.

Therefore, the insulated wire of the present invention is excellent in flame resistance, cold resistance and external damage resistance, and the one obtained by electron beam cross-linking the insulator has further improved heat resistance and mechanical properties. Become. Furthermore, since the resin composition forming the outermost layer and the innermost layer does not contain halogen or heavy metal, no harmful halogen-containing gas is generated even if incinerated, and heavy metal or The phosphorus compound does not flow out and does not pollute the environment.

Specific examples will be shown below. The resin composition A forming the outermost layer and the resin composition B forming the innermost layer having the blended composition shown in Table 1 and Table 2 were prepared, and using this, an insulated wire having a two-layer structure was manufactured. The outer diameter of the conductor was 0.5 mm, the resin compositions A and B were coated by the simultaneous two-layer extrusion coating method, and electron beams were further irradiated under the condition of 1 Mrad to crosslink. Note that some of them are not crosslinked without being irradiated with an electron beam. These were evaluated for trauma resistance, cold resistance, flame retardancy, and mechanical properties.

The cold resistance was evaluated as ◯ when the embrittlement temperature measured by the ASTM method was −10 ° C. or less, and as x when it was not. The flame retardancy was rated as ◯ when it passed VW-1 of UL standard, and as x when it was not. Trauma resistance is
Using a NEMA abrasion tester, the outer diameter of the cylindrical portion of the needle is 0.8 mm, the surface of the wire is ground 10 times, and the depth of wear is observed with a microscope.
Those exceeding 0.1 mm were marked with x. As for the mechanical properties, those having an elongation at break of 100% or more were evaluated as ◯, and those not so were evaluated as x. The results are shown in Table 3.

The materials used in Tables 1 and 2 are as follows. "Ionomer * 1" melt flow rate 1.0, zinc "Ionomer * 2" melt flow rate 5.0, zinc "ethylene-methacrylic acid copolymer * 1" methacrylic acid content 4 mol%, melt flow rate 7 " Ethylene-methacrylic acid copolymer * 2 "Methacrylic acid content 12 mol%, melt flow rate 14" EVA "Vinyl acetate content 33 wt%, melt flow rate 0.1 ethylene-vinyl acetate copolymer" EEA "ethyl Ethylene-ethyl acrylate copolymer with 14 wt% acrylate and 1 melt flow rate

"Ethylene Acrylic Rubber" Ethylene 40
Ethylene acrylic rubber containing 50% by weight of methyl acrylate 60% by weight "Magnesium hydroxide * 1" Magnesium hydroxide surface-treated with vinylsilane coupling agent "Magnesium hydroxide * 2" Magnesium hydroxide surface-treated with stearic acid "Flame retardant aid Agent "Zinc hydroxystannate

[0042]

[Table 1]

[0043]

[Table 2]

[0044]

As described above, in the insulated wire of the present invention, the insulator is composed of two or more layers, the outermost layer thereof is made of a resin composition having high scratch resistance, and the innermost layer is flame-retardant and flexible. Since it is composed of a resin composition having a high property, it has excellent trauma resistance, flame retardancy, cold resistance and mechanical properties, and the crosslinked product also has a high heat resistance. Further, even if incinerated, no harmful halogen-containing gas is generated, and no heavy metal residue remains.

Continued front page    (72) Inventor Katsuyoshi Ishida             1-5-1 Kiba Stock Market, Koto-ku, Tokyo             Inside Fujikura F-term (reference) 5G313 AB01 AB08 AB09 AC02 AD03                       AE02 AE07 BA01                 5G315 CA03 CA04 CB02 CC09 CD04                       CD14

Claims (5)

[Claims] 1. An insulated wire in which a conductor is covered with an insulator, wherein the insulator has two or more layers, and the outermost layer is composed of a scratch-resistant composition. 2. An insulated wire in which a conductor is coated with an insulator, wherein the insulator has two or more layers, and the outermost layer is 100 parts by weight of an ionomer or ethylene-methacrylic acid copolymer, and 300 mg of magnesium hydroxide.
The resin composition A contains 20 parts by weight or less of the flame retardant aid, and the innermost layer thereof has 40 to 90 parts by weight of an ethylene copolymer, 5 to 50 parts by weight of ethylene acrylic rubber, and an ionomer. Or ethylene-methacrylic acid copolymer 0.5 to 5
A flame-retardant resin composition B comprising 40-200 parts by weight of magnesium hydroxide and 1-20 parts by weight of a flame-retardant aid with 100 parts by weight of a base polymer consisting of 0 parts by weight. Insulated wire to be used. 3. The insulated wire according to claim 2, wherein 50 wt% or more of magnesium hydroxide contained in the outermost layer and the innermost layer is surface-treated with a silane coupling agent. 4. The insulated wire according to claim 1, wherein the insulator has a thickness of 1 mm or less and the outermost layer has a thickness of 0.05 to 0.4 mm. 5. The insulated wire according to claim 1, wherein the insulator is cross-linked by being irradiated with an electron beam.