JPH0686556B2 - Flame-retardant electrically insulated wire - Google Patents

Description

TECHNICAL FIELD The present invention relates to a flame-retardant electrically insulated wire having good irradiation crosslinkability.

[Conventional technology]

As an insulating coating material for electric wires for electric devices, electric wires for vehicles, electric wires for ships, or other electric wires and cables, it has flexibility and mechanical properties to withstand wiring work under normal conditions and normal operation. Is required to be excellent and flame retardant.

Many of the compositions used in conventional flame-retardant electrically insulated wires have a problem of generating a large amount of harmful halogen-containing gas due to combustion because they are flame-retarded by adding a halogen-based flame retardant. Therefore, recently, there has been a strong demand for halogen-free, in other words, low-pollution flame-retardant compositions, and therefore, it is a low-pollution composition containing a non-halogen flame retardant such as magnesium hydroxide. In addition, various flame-retardant electrically insulated electric wires using a polyolefin-based flame-retardant composition having excellent flexibility and mechanical properties have been proposed.

[Problems that need to be solved] By the way, whether a polyolefin composition flame-retarded by adding a halogen-based flame retardant or a low-pollution polyolefin composition containing a non-halogen flame-retardant, copper When electron beam irradiation cross-linking is carried out in the presence of, there is a problem that eccentric trees are generated in the composition. In particular, the tree tends to easily occur in a polyolefin composition containing a non-halogen flame retardant.

When cross-linking organic polymers by electron beam irradiation,
When the organic polymer is irradiated with an electron dose sufficient to obtain the required degree of crosslinking, discharge deterioration may occur inside the organic polymer, and deterioration marks may be generated. Since this deterioration mark has a tree-like shape and the phenomenon was unexpected, the tree-shaped deterioration mark is called an eccentric tree. There is a problem that it has already been subjected to electrical breakdown before being used as a material and is no longer usable as an insulating material.

[Means for solving problems]

In view of the above circumstances, the present invention aims to provide a flame-retardant electrically insulated wire in which the problem of eccentric tree generation is improved even when electron beam irradiation crosslinking is performed in the presence of copper.

That is, the present invention, per 100 parts by weight of at least one selected from polyethylene and ethylene-vinyl acetate copolymer, 50 to 200 parts by weight of a halogen-free flame retardant, a copper damage inhibitor
0.05 to 5 parts by weight, hindered phenolic antioxidant 0.
A flame-retardant flame-retardant composition comprising 05-8 parts by weight and 0.05-6 parts by weight of a sulfur-based antioxidant, which is extrusion-coated on a conductor and then crosslinked by electron beam irradiation. Electrical insulated wire.

[Action]

By using the composition of the present invention, even if the composition is extrusion-coated on a conductor and then crosslinked by electron beam irradiation, the above-mentioned problem of eccentric tree generation is improved.

In the present invention, at least one selected from polyethylene and ethylene-vinyl acetate copolymer is used in the composition. Examples of polyethylene include those of various densities, preferably linear low-density polyethylene (a copolymer of ethylene with an olefin having 4 to 16 carbon atoms, a density of 0.90 to 0.94, and a melt index (MFR) of
An essentially linear polyethylene that is 0.1 to 20,
For example, those produced by polymerizing the above-mentioned olefin raw material under low pressure in the presence of a catalyst) and the like. Among the above-mentioned linear low-density polyethylene, it is preferable that the olefin as the comonomer to be copolymerized with the ethylene chain constituting the polyethylene has about 4 to 10 carbon atoms, and more specifically, the comonomer is butene-.
Most preferred are 1, octene-1 and 4-methylpentene-1. Among the above linear low-density polyethylenes, those having a density of about 0.91 to 0.94 measured by ASTM D1505 are preferable. Further, among the above linear low-density polyethylene, those having an MFR measured by ASTM D1238 of about 0.1 to about 10 are preferable, and those having a density of about 0.911 to 0.925 are preferable.

Non-halogen flame retardants include alumina hydrates such as aluminum hydroxide, metal oxide hydrates such as magnesium hydroxide and hydrotalcite, antimony trioxide, antimony pentoxide, titanium dioxide, zinc oxide. , Metal oxides such as magnesium oxide and aluminum oxide,
Alternatively, other inorganic flame retardants such as zinc borate and magnesium carbonate, or phosphorus-based organic flame retardants such as organic phosphoric acid ester and red phosphorus. As the red phosphorus, those commercially available in the past can be widely used. For example, the red phosphorus content is 80% by weight or more, the loss on drying is 0.8% by weight or less, and the 74 mesh sieve residue is 7% by weight. The following are preferable. Further, it is also preferable that the surface of the above-mentioned red phosphorus is coated with a thermosetting resin such as phenol-formalin resin. As a specific example, Novarred # 120,
Novared # 120UF (all manufactured by Rin Kagaku Kogyo Co., Ltd.) and the like can be mentioned.

As a copper damage inhibitor, 3- (N-salicyloyl) amino-1,2,4-triazole and 2,2'-oxamidobis- [4
-Ethyl-3- (3,5, -di-t-butyl-4-hydroxyphenyl) propionate], amide derivative, oxalic acid bis (benzylidene hydrazide),
Isophthalic acid bis (2-phenoxypropionyl hydrazide) and the like can be mentioned.

Examples of the hindered phenolic antioxidant include polybutylated bisphenol A and 2,6-di-t-butyl-
p-cresol, 2,5-di-t-amylhydroquinone, 2,5-di-t-butylhydroquinone, 2,2-methylene-bis- (6-t-butyl-4-methyl-phenol), 2, 6-bis (2'hydroxine-3'-t-butyl-5'-methyl-benzyl) -4-methyl-phenol, 2,2-methylene-bis (4-methyl-6-t-butyl-phenol) , 4,4'-methylene-bis (2,6-di-t-butyl-phenol), 1,3,5-tri-methyl-
2,4,6-Tris (3,5-di-t-butyl-4-hydroxy-benzyl) benzene, tetrakis [methylene-3-
(3,5-Di-t-butyl-4-hydroxy-phenyl) propionate] methane, n-octadecyl-3-
(4'-Hydroxy-3'5'-di-t-butylphenol) propionate, 2,5-di-t-butylhydroquinone, 2,2'-methylene-bis (4-methyl-6-t-)
Butyl-phenol), 4,4'-butylidene-bis (3
-Methyl-6-t-butyl-phenol), 1,1,3-tris (2-methyl-4-hydroxy-5-t-butyl-phenyl) butane, and the like.

As the sulfur-based antioxidant, pentaerythritol tetrakis (β-laurylthiopropionate), 2,2-thio [diethyl-bis-3 (3,5-di-t-butyl-4-)
Hydroxyphenol) propionate], lauryl-stearyl thiodipropionate, dilauryl thiodipropionate, distearyl thiopropionate, 4,
4'-thio-bis (6-t-butyl-3-methyl-phenol), ditridecylthiodipropionate, terephthaloyldi (2,6-di-methyl-4-t-butyl-3-hydroxybenzyl sulfide), Bis (3-methyl-4-
Examples thereof include hydroxy-5-t-butyl-benzyl) sulfide and distearyl β, β'-thiodibutyrate.

Regarding the blending ratio of the above components in the present invention,
Per 100 parts by weight of at least one selected from polyethylene and ethylene-vinyl acetate copolymer, 50 to 200 parts by weight of a non-halogen flame retardant, 0.05 to 5 parts by weight of a copper damage inhibitor, and a hindered phenolic antioxidant 0.05 to 8 parts by weight, and the sulfur-based antioxidant is 0.05 to 6 parts by weight.

If the content of the non-halogen flame retardant is less than 50 parts by weight,
A composition having good flame retardancy cannot be obtained. On the other hand, when the amount of the halogen-free flame retardant compounded is more than 200 parts by weight, the mechanical properties and processability of the composition deteriorate. Copper damage inhibitor, hindered phenol-based antioxidant, and sulfur-based antioxidant are blended at 0.05 parts by weight, 0.05 parts by weight, and
If it is less than 0.05 parts by weight, the effect of preventing the generation of eccentric trees during electron beam irradiation crosslinking in the presence of copper is poor, while on the other hand, it is a copper damage inhibitor, hindered phenol-based antioxidant, and sulfur-based antioxidant. When the compounding amount of each inhibitor is more than 5 parts by weight, 8 parts by weight, and 6 parts by weight respectively, the effect of preventing the generation of eccentric trees is saturated immediately, and any further compounding is economically disadvantageous. .

Therefore, the preferred blending amount of the non-halogen flame retardant is 70 to 150 parts by weight, particularly 80 to 130 parts by weight, per 100 parts by weight of at least one selected from polyethylene and ethylene-vinyl acetate copolymer, and a copper damage inhibitor. Is preferably 0.1 to 4 parts by weight, particularly 0.2 to 3 parts by weight, per 100 parts by weight of at least one selected from polyethylene and ethylene-vinyl acetate copolymer, and the preferred amount of hindered phenolic antioxidant is Is 0.1 to 6 parts by weight, particularly 0.2 to 4 parts by weight, per 100 parts by weight of at least one selected from polyethylene and ethylene-vinyl acetate copolymer, and the preferable blending amount of the sulfur-based antioxidant is polyethylene and It is 0.1 to 5 parts by weight, particularly 0.2 to 4 parts by weight, per 100 parts by weight of at least one selected from ethylene-vinyl acetate copolymers.

The flame-retardant electrically insulated electric wire of the present invention can be obtained by subjecting the above-mentioned composition to extrusion coating on, for example, a copper conductor, and then subjecting it to electron beam irradiation crosslinking by a usual method. that time,
It is preferable to use a commonly used crosslinking aid. Preferred cross-linking aids include aliphatic or aromatic polyfunctional compounds, aliphatic polyfunctional cyclic compounds, nitrogen-containing polyfunctional cyclic compounds, metal-containing polyfunctional compounds, and especially nitrogen-containing polyfunctional compounds. Functional cyclic compounds, especially triallyl isocyanurate (TA
IC), trialtaallyl isocyanurate (TMAIC), triallyl cyanurate (TAC), triacroylhexahydro-1,3,5-triazine (TAF) and the like.

The amount of the crosslinking aid used is 0.1 to 5 parts by weight, particularly 0.5 to 2 parts by weight, per 100 parts by weight of at least one selected from polyethylene and ethylene-vinyl acetate copolymer.

Inorganic fillers, coupling agents, processing aids, pigments and the like may be added to the composition used for the flame-retardant electrically insulated wire of the present invention.

〔effect〕

INDUSTRIAL APPLICABILITY The flame-retardant electrically insulated wire of the present invention has good flexibility, mechanical properties, and flame retardancy, and moreover, eccentric tree is not easily generated even by electron beam irradiation cross-linking, so that it has high withstand voltage strength. Is also excellent. Therefore, the flame-retardant electrically insulated electric wire of the present invention can be suitably used for electric wires for electronic devices, electric wires for vehicles, electric wires for ships, or other electric wires and cables.

〔Example〕

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples.

The compositions (composition ratio is parts by weight) in the various examples and comparative examples shown in the attached table are kneaded with a two-roll mill, and then the cross-sectional area is 8 mm.
The copper wire of No. ² was extrusion coated to obtain an uncrosslinked coated electric wire having an insulating layer thickness of 1 mm. Then, an electron beam was irradiated at a dose of 25 Mrad to manufacture a crosslinked electric wire.

The crosslinked coating was peeled off and sampled, and the sample collected was measured for flame retardancy, mechanical properties, and the presence or absence of eccentric trees, and the results are shown in the same table.

Flame retardance: Measure the oxygen index by the method specified in JIS K7201.

Presence or absence of eccentric tree: A sample with a length of about 10 cm was taken from the obtained cross-linked wire, the copper conductor in the center was removed, and then the insulating layer was cut into slices with a thickness of about 500 μm. The presence of eccentric trees was investigated by observing transmitted light with a microscope.

The contents of each note in the attached table are as follows.

Note 1 ... Evatate H2031, manufactured by Sumitomo Chemical Co., MFI: 1.5,
VA content: 20% by weight, Note 2: Mitsubishi Yuka Co., Ltd. Yucaron ZF-30, MFR: 1.0, Note 3: Kyowa Chemical Industry Co., Kisuma 5B, Note 4: Showa Light Metal Co., Ltd. Heidi Light H42M, Note 5 ... Mitsubishi Kasei Diamond Black H, Note 6 ... 3- (N-salicyloyl) amino-1,2,4-
Triazole, Note 7 ... 2,2'-Oxamidobis- [4-ethyl-3
-(3,5-di-t-butyl-4-hydroxyphenyl) propionate], Note 8 ... Isophthalic acid bis (2-phenoxypropionyl hydrazide), Note 9 ... 2,6-di-t- Butyl-p-cresol, Note 10 ... 4,4'-Methylene-bis (2,6-di-t-butyl-phenol), Note 11 ... Tetrakis [methylene-3- (3,5-di-t] −
Butyl-4-bydoxy-phenyl) propionate] methane, Note 12 ... Lauryl-stearyl thiodipropionate,
Dilauryl thiodipropionate, Note 13 ... Ditridecyl thiodipropionate, Note 14 ... 4,4'-thio-bis (6-t-butyl-3-methyl-phenol)

Continuation of the front page (51) Int.Cl. ⁵ Identification number Reference number within the agency FI Technical display area H01B 3/44 M 9059-5G // (C08K 13/02 3:00 5:00) (56) References Kai 49-32941 (JP, A) JP 52-11238 (JP, A) JP 52-11237 (JP, A) JP 62-192435 (JP, A) JP 43-16845 ( JP, B1) JP-B 43-16288 (JP, B1) JP-B 1-18097 (JP, B2)

Claims (1)

[Claims] 1. A halogen-free flame retardant, 50 to 200 parts by weight, and a copper damage inhibitor, 0.0, per 100 parts by weight of at least one selected from polyethylene and ethylene-vinyl acetate copolymer.
5 to 5 parts by weight, hindered phenolic antioxidant 0.05
~ 8 parts by weight, and a composition containing 0.05 to 6 parts by weight of a sulfur-based antioxidant, after extrusion coating on a conductor,
A flame-retardant electrically insulated electric wire, which is crosslinked by electron beam irradiation.