JPH02189809A - Flame retardant wire/cable - Google Patents

Abstract

PURPOSE:To prevent noxious, corrosive hydrogen halide gas from being produced during burning by covering a conductor or an insulated core wire with flame retardant polyolefine compounds obtained by addition of metal hydrate and a foaming agent to polyolefine. CONSTITUTION:A flame retardant polyolefine compound fabricated by addition of metal hydrate, a foaming agent and if necessary a flame retardant assistant to polyolefine is used for covering a conductor or an insulated wire to obtain a flame retardant wire/cable. The foaming agent is decomposed and foams during burning to expand a nonhalogen covering film so that a strong foaming adiabatic layer is formed. During burning, generation of hydrogen halide gas is prevented as a result and that of smoke is also reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION 1. Field of Industrial Application] The present invention relates to flame-retardant wires and cables that do not emit halogen during combustion and have excellent heat insulation properties.

[Conventional technology 1] In recent years, as the idea of disaster prevention has increased,
Not only is it difficult to burn, but it also contains toxic gas, 1 starvation, 1
'11 There is a growing demand for products that generate less gas and black smoke.

For example, polyvinyl chloride, borikolobrene rubber, and various fluoropolymers and fluororubbers, which contain hydrogen in the molecule, have been prized for their excellent combustibility. These are present at the time of combustion and Il! It generates a large amount of edible hydrogen halide gas, which is a problem.

On the other hand, even polyolefins such as polyethylene, which do not contain halogens, are flame-retardant using halogen-based flame retardants containing chlorine and bromine. Its occurrence is inevitable.

Therefore, recently, polymers such as polyethylene that do not contain a halogen in the molecule are used as base materials, and endothermic inorganic compounds that contain a large amount of water of crystallization in the molecule and do not contain halogens, such as aluminum hydroxide, have recently been added. The so-called non-HA 1-1 polyolefin material added as a flame retardant is
It is known for its flame-retardant binding, which does not produce toxic corrosive scum when burned, but also produces little smoke, and is attracting attention as an insulator or sheath material, especially in the field of electric wires and cables.

[Problems to be Solved by the Invention] However, for example, when insulators for cable cores are used...F'l I, J 13+, and the soil is coated with the non-ha[-1] polyolefin grains. When we consider the cables that were used, we found that the non-ha[-1 Gemboriolefin material II is simply flammable;
Liquefaction, gasification, and
It is necessary to have an ignition prevention effect, that is, a heat insulation effect; otherwise, there is a problem that the scope of application to electric wires and couples will be limited.

Also, the formation of a carbonized layer during combustion must be taken into account, and it is not helpful if cracks, cracks, or falling F occur. In order to solve these problems, it is necessary to use more flame retardant than necessary or to increase the thickness of the coating, but these measures will reduce the performance of wires and cables. , which is undesirable from the viewpoint of economy, space, etc.

An object of the present invention is to eliminate the drawbacks of the prior art mentioned above and to provide wires and cables coated with a heat-insulating material that exhibits a heat insulating effect during combustion without impairing the advantages of the non-halogen materials mentioned above. .

Means and operation for solving the problem The gist of the present invention is to prepare a flame-retardant polyolefin composition prepared by adding a blowing agent such as a metal hydrate to a polyolefin and, if necessary, a combustion aid. The insulated wire core is coated with the foam so that the foaming agent decomposes and foams during combustion, expanding the non-hazardous coating to form a strong foamed heat insulating layer.

The above-mentioned polyolefins include low, medium, and high density polyethylenes, polyolefins such as boria, pyrene, and polybutene 1.
α-olefin; poly-α-olefin copolymer such as bran-1, p[]pyrene, etc. and ethylene; poly-α-olefin copolymer such as b[l-crandyno-1] polymer; 21-nytylene vinyl acetate copolymer; Examples include acrylate copolymers, Eblene-propylene resins, etc.
Two or more of these iI'A compounds may also be used.

Typical examples of metal hydrates include aluminum hydroxide, magnesium hydroxide, zinc borate, Hyde[]Talzai 1~, Dawsonite, etc., but are not limited to these. There are no particular restrictions on the amount of metal hydrate added, but if it is less than 50 parts by weight per 100 parts by weight of polyolefin, the flame retardancy will be low, and if it exceeds 200 parts by weight, problems will occur in physical properties, processability, etc. generally 50
The 1° blowing agent, which is preferably 200 parts by weight, may be either an organic or an inorganic blowing agent, but in practical terms, it decomposes at a temperature below the molding temperature of the flame-retardant polyolefin, for example 150°C. , it is necessary that no foaming occurs. What are the typical blowing agents?)! Zodicarbonamide, azobisformamide, N, N'
Examples include azo-based compounds such as -dini-1-lone pentamedylene detramine, oxybisbenzene sulfohydrazide, etc., 21-1]one-based compounds, and sulfonyl hydrazide-based compounds.

In order to adjust the decomposition rate and decomposition temperature of these blowing agents, auxiliary agents such as inorganic salts such as zinc oxide and metal soaps such as lead stearate may be used. Moreover, in order to obtain good foaming, two or more foaming agents having different decomposition temperatures can be used in combination.

Typical flame retardant additives added to the above composition as needed are red phosphorus, carbon black, etc., but red phosphorus with an ignition point of 260°C or higher and a particle size of 10μ or less is particularly difficult to use. It is preferable in that the flammability, that is, the oxygen index, can be significantly increased, and it is even more preferable to coat the particle surface with, for example, melamine resin, phenol resin, etc. for safety in handling.

In addition, phosphorus compounds such as phosphorus pentoxide and melamine phosphate are also useful. Carbon black is effective in strengthening ash during combustion, and is also effective in preventing surface scratches, which are disadvantages of non-halogen materials, and in improving weather resistance. No J-
As the bomb, any one of 17-channel, fluorescein, thermal, and acetylene may be used.

The addition amount of the flame retardant aid is preferably 10 parts by weight or less of red phosphorus and 14 parts by weight or less of 550 parts of carbon black, respectively, per 100 parts by weight of polyolenoin.

In addition, antioxidant 11-agents, lubricants, colorants, etc.
Additives commonly used in gemboriolefin flame retardant compositions can be used as they are.

The foamable carp retardant polyolefin composition described in "-" may be subjected to crosslinking and reticulation treatment. Crosslinking methods include using an organic peroxide such as dicumyl perionide (chemical crosslinking method using heat crosslinking, radiation crosslinking method using J energy rich rays such as electron beams and alpha rays, and vinyl silane with bar Δ There is a silane-water crosslinking method in which a polyolefin is added to Silangraph 1 with Kyrieid and crosslinked in a water atmosphere.By crosslinking the composition of the present invention using these crosslinkers, , the polymer viscosity becomes larger compared to that of non-crosslinked polymers,
- It is possible to form an effective foam insulation layer.

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

Example 1 A composition prepared by adding 100 parts by weight of ethylene-ethyl acrylate copolymer, 100 parts by weight of aluminum hydroxide, and 1 part by weight of azodicarbonamide was applied to a conductor having an outer diameter of 1.2 mm to a thickness of 1.4 mm. An electric wire was manufactured by extrusion coating an insulated wire core having an outer diameter of 4.0 mm to a thickness of 1.0 mm, which was made by coating a polyethylene insulator.

Example 2 A composition obtained by adding 1 part by weight of aluminum hydroxide, 2 parts by weight of red phosphorus, and 1 part by weight of azodicarbonamide to 100 parts by weight of the copolymer was prepared in Example 1. An electric wire was manufactured by extrusion coating onto the same insulated wire core to a thickness of 1.0#.

Example 3 Each of the electric wires obtained in Examples 1 and 2 was crosslinked by irradiating it with an electron beam of 30 Mrad.

Comparative Example 1 A composition prepared by adding 100 parts by weight of aluminum hydroxide to 100 parts by weight of ethylene-ethyl acrylate copolymer was extruded onto the same insulated wire core as in Example 1 to a thickness of 1.0M. (I coated wires to make electric wires.)

Comparative Example 2 A composition obtained by adding 100 parts by weight of ethylene delacrylate copolymer, 100 parts by weight of aluminum hydroxide, and 2 parts of red phosphorus was added to the same insulated wire core as in Example 1.
．． An electric wire was manufactured by extrusion coating to a thickness of 0 mm.

Combustion Test) The electric wires of Examples 1 to 3 and Comparative Example were subjected to the I'R-1 combustion test described in U.L. Then, the state of fire spread was examined when flame contact was performed five times at intervals of 15 seconds, and those with a fire spread time of less than 60 seconds were judged to have passed.

As a result, all the electric wires of Examples 1 and 3 passed the test, and the foaming state of the sheath coating during combustion was good, and the heat insulation effect was large. Note that the electric wire of Example 3 had the best foamed heat insulating layer during combustion.

On the other hand, the electric wire of Comparative Example 1 ignited the inner layer of polyethylene on the fourth flame contact and continued to spread for more than 60 seconds, and the electric wire of Comparative Example 2 ignited the inner layer of polyethylene on the fifth flame contact. The fire spread and continued for more than 60 seconds, and all were rejected.

[Effects of the Invention] As explained above, according to the present invention, the flame-retardant polyolefin does not generate toxic and corrosive hydrogen halide gas when burned, and the amount of smoke generated can be reduced. This has the effect of providing flame-retardant wires and cables in which the foaming agent effectively decomposes and expands when exposed to flame, forming an expanded foamed heat insulating layer, without sacrificing the advantage of having a small amount of heat.

Claims (2)

[Claims] 1. A flame-retardant electric wire/cable characterized in that a conductor or an insulated wire core is coated with a flame-retardant polyolefin composition made by adding a metal hydrate and a foaming agent to polyolefin. 2. A flame-retardant electric wire/cable characterized in that a conductor or an insulated wire core is coated with a flame-retardant polyolefin composition made by adding a metal hydrate, a flame retardant aid, and a foaming agent to polyolefin.