JPS6149310A - Flame resistant cable - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a halogen-free flame-retardant cable, and in particular, a so-called halogen-free material that does not contain a halogen element in the insulator, sheath, and other cable constituent materials. The present invention relates to a flame-retardant cable that has a flame-retardant structure, does not generate toxic gas in the event of a fire, produces less smoke during combustion, and prevents melting and outflow of insulators and the like.

<Conventional technology> In conventional general cables, polyethylene (PE) or cross-linked polyethylene (XLP) is used as an insulator.
E), etc., and for multi-core cables, polypropylene, polyester, jute, kraft paper, etc. are used as the intervening material.

Particularly when trying to make the cable flame retardant, the sheath part of the insulator is made of halogen-containing materials such as polyvinyl chloride, polychloroprene rubber, chlorosulfonated PE rubber, and chlorinated PE. by mixing antimony trioxide, etc., or using flammable resins such as polyethylene, ethylene-vinyl acetate copolymer (EVA), ethylene-ethyl acrylate (EEA), and ethylene propylene (EP) rubber, and adding chlorine to these. Flame retardance is imparted by mixing a bromine-based or bromine-based flame retardant with the above-mentioned antimony trioxide.

For this reason, when conventional cables of this type are heated to high temperatures in the event of a fire, the combustion of the sheath itself is suppressed as much as possible in the flame-retardant sheath part, but the base resin and flame retardant itself are When a halogen element is contained, a large amount of toxic gas such as hydrogen halide gas or halogen gas is generated, and a large amount of smoke is also generated. Therefore, there are problems in terms of safety, and it is not suitable for use in places where high safety is required, such as subway stations, underground malls, ships, and nuclear power plants. Further, since hydrogen halide gas is a highly corrosive gas, it can corrode conductors and surrounding metals, which can significantly impair functions such as automatic control.

In addition, when the internal components inside the cable core, such as insulators and intervening materials such as polyethylene and cross-linked polyethylene, are exposed to combustion flames, they melt and flow as drips, and when they reach the cable surface, they are exposed to high-temperature environments. Because the cable turned into gas, it was immediately ignited, causing serious problems such as the cable itself becoming a combustion source and further exacerbating the fire.

Therefore, for flame-retardant cables that are intended to be more disaster-free, it is necessary to use so-called non-halogen materials that do not contain halogen elements to make them flame-retardant. As a flame retardant method that does not rely on halogen elements, a method has already been proposed in which a large amount of metal hydrate is added to base materials such as rubber and plastics. , there are problems such as deterioration of mechanical properties.

Furthermore, in order to improve the heat resistance of insulators, sheaths, etc., it is necessary to crosslink them, but in the case of electron beam crosslinking,
If a large amount of metal hydrate is contained as described above, electron beam permeability may be poor and crosslinking efficiency may not be considered. Furthermore, in the case of organic peroxide crosslinking, a high-temperature, high-pressure atmosphere such as steam or gas is required, which tends to cause deformation of the core inside the cable, making continuous production difficult in the case of multi-core cables. Furthermore, in the case of silane crosslinking,
What happens when you add the large amount of flame retardant required to a silane-grafted resin? A problem arises in that the crosslinking reaction progresses during R kneading, making molding difficult and making it impossible to obtain a good appearance.

Therefore, when blending the mixture for cables, it is necessary to consider the balance of cable properties. In other words, there is a certain limit to the improvement in flame retardancy only by adjusting the blend of flame retardants and the like.

Therefore, in order to further increase the distance between cables and tA,
At the same time, we aim to make the materials themselves such as the insulator and sheath flame retardant, and from the perspective of the cable structure, we also prevent melted drip material from flowing onto the cable surface, and prevent it from collapsing or collapsing in the event of a fire. It is necessary to have a structure that does not lose its shape and cuts off the supply of oxygen to the inside of the core. In particular, as mentioned above, when the insulator, sheath, etc. must be made of halogen-free rubber or plastic materials to make the cable halogen-free, it is unavoidable to use halogen-containing rubbers, plastics, or even halogen-based materials. The flame retardant structure of the cable structure is also important, since the flame retardancy tends to be lower than when nonflammable agents are used.

<Problems to be Solved by the Invention> The present invention has been made in view of the above-mentioned conventional problems, and its purpose is to use non-halogen rubber for insulators, sheaths, and other constituent materials. In addition to using plastics, non-halogen element-based flame retardants are used. Especially for the sheath, a reasonable blending range of admixtures is selected, heat resistance is imparted by silane cross-linking, and the cable structure is We decided to provide a so-called clean disaster prevention cable that has a flame-retardant structure using a frame barrier layer, barrier protection layer, carbonized tape layer, etc., and is flame-retardant and generates less halogen gas and smoke. be.

Means for Solving the Problems> Te 1 of the present invention [Flammable cables are basically insulated cables with an insulator made of rubber or plastic (excluding those containing halogen elements) on the conductor. On the outside of the wire core or on the outside of the insulated wire core bundle made by twisting these wires, in turn, apply a nonflammable inorganic tape material mainly made of ceramic, or a metal tape material, or an organic material with an oxygen index value of 35 or more. jffl M8 tape material, or a frame barrier layer formed by laminating at least two types of tape materials, and 100-X parts by weight of polyolefin resin (excluding those containing halogen elements) containing metal. A polyolefin resin mixture containing 50 to 200 parts by weight of a hydrate is added with A silane crosslinked sheath is applied to which a silane-grafted polyolefin resin mixture (excluding those containing a halogen element) containing ~50 parts by weight of a red phosphorus flame retardant is added. If necessary, a carbonized tape layer that is carbonized by heating is provided inside the frame rear layer, or a barrier protection layer that protects the frame barrier layer is provided outside of the carbonized tape layer.

The flame retardant cable of the present invention will be explained in more detail with reference to the drawings as shown in FIGS. 1 to 4.

In these cables, 1 is a conductor, 2 is an insulator,
Absolutely form N9=heart 3. 4 is an interposition, 5 is a frame barrier layer provided on the cable core, 6 is a carbonized tape layer provided inside the frame barrier layer 5 and carbonized by heating, and 7 is a barrier protection layer provided outside the frame barrier layer 5. , 8 is a sheath.

The insulator 2 of the cable is made of so-called non-halogen rubber or plastic that does not contain any halogen elements, such as PE.
, crosslinked PE, natural rubber, butyl rubber, silicone rubber, ethylene propylene rubber (EPM), ethylene propylene diene elastomer (EPDM), ethylene-vinyl acetate copolymer, ethylene and ethyl acrylate copolymer,
It is made of a copolymer of ethylene and α-olefin, an ethylene acrylic elastomer, a hydrogenated styrene butadiene elastomer, a blend thereof, or a flame retardant made by adding a non-halogen flame retardant to these. When using XLPE (crosslinked polyethylene) as the insulator 2, for example, organic peroxides such as DCP (dicumyl peroxide), 2,5-dimethyl-2,5di(t Chemical crosslinking methods, such as a method using hexane (-butylperoxine) or a so-called silane crosslinking method using a silane coupling agent such as vinyl alkoxysilane, or an electron beam crosslinking method can be employed. The interposer 4 is made of jute, paper, non-moisture treated paper, flame retardant treated paper, flame retardant polypropylene (PP), PP yarn, polyethylene terephthalate film, etc.

The frame barrier layer 5 is a layer for protecting the insulator 2, the interposer 4, etc. of the wire core bundle from fire in the event of a fire, and is made of a nonflammable inorganic tape material mainly made of ceramic or the like.
Alternatively, a metal tape material, a flame-retardant tape material mainly composed of an organic material having an oxygen index value of 35 or more, or a combination of at least two types of tape materials thereof. Here, examples of inorganic tape materials include mica mylar tape, mica glass tape, mica-Gi mixed tape, ashesto tape, mica-Gi laminate tape,
silicone or alkyd varnished glass tape,
Examples include composites of alumina/silica melt-spun tape (kao wool, ceramic fiber, etc.) and glass fiber, and tapes such as alumina/glass laminates. Examples of metal tape materials include copper (Cu), iron,
(Fe), stainless steel (SUS), brass, aluminum (A1), and aluminum/mylar laminate tape. Further, flame-retardant tapes mainly made of organic materials with an oxygen index value of 35 or higher include, for example, polyetheretherketone (PEEK), polyimide resin, flame-retardant rubberized cloth tape, polyethersulfone, polyetherimide polysulfone, polycarbonate, Examples include phenol resin and aromatic polyester. Furthermore, it is also possible to use a combination of two or more of the above inorganic tapes, metal tapes, and tapes mainly composed of organic materials having an oxygen index value of 35 or more. The actual coating method is, for example, in the case of inorganic tape material or organic flame retardant tape material, 0.05 to 0.2 t thick is wrapped in 115 to 1/2 wraps, about 1 to 5 sheets. Thickness 0.03~0.2 for winding or metal tape material
It is formed by winding about 1 to 3 pieces of one or two types of tape in 175 to 172 laps of 1IIt.

The carbonized tape layer 6 is made of kraft paper, acrylic fiber cloth, human silk cloth, natural cellulose fiber, or a cloth tape obtained by impregnating these with silicone varnish, alkyd varnish, etc., and is applied by wrapping in the same manner as the frame barrier single layer. Note that this carbonized tape layer 6 is omitted in the cables shown in FIGS. 3 and 4.

The barrier protection layer 7 that protects the frame barrier layer 5 is
For example, it is made by winding a tape made of inexpensive asbestos, glass, ceramic fiber, or a composite of these materials. Note that this layer is omitted in FIGS. 2 and 4.

On the other hand, the sheath 8 is made of a polyolefin resin that does not contain a halogen element, such as PE, ethylene-α-olefin copolymer, EVA, EEA ethylene acrylic elastomer, ethylene propylene copolymer, and ethylene propylene diene elastomer. Alternatively, metal hydrates, such as aluminum oxide hydrates (A
1203 ・3H,O), hydrate of magnesium oxide (
M g 0-Hz O), basic magnesium and calcium hydroxide, or hydrates of these metals with surface treatment using fatty acid silane, knobling agent, phosphate ester, etc. are added. The polyolefin resin mixture contains 2 to 5 silane-grafted polyolefin resin and carbon black or red phosphorus components.
It is formed from a silane-grafted polyolefin resin mixture (excluding those containing halogen elements) mixed with 0 parts by weight of a red phosphorus flame retardant. Here, the blending amount of these is 50 to 200 parts by weight of the metal hydrate per 100-X parts by weight of the polyolefin resin, and X parts by weight of the silane-grafted polyolefin resin (where X is 5 parts by weight).
-80), 5 to 40 parts by weight of Kabonburasok or 2 to 50 parts by weight of the above red phosphorus-based retardant.Then, this silane-grafted polyolefin resin mixture and the polyolefin resin of the above metal hydrate. The mixture is a mixture of resin components, that is, a polyolefin resin and a silane-grafted polyolefin resin, in an amount of 100 parts by weight.In other words, 20 to 95 parts by weight of the polyolefin resin and 50 to 200 parts by weight of the metal hydrate. If the polyolefin resin is less than 20 parts by weight, extrusion processability is poor, if it is more than 95 parts by weight, almost no degree of crosslinking can be obtained, and if the metal hydrate is less than 50 parts by weight, there is sufficient difficulty in extrusion processability. This is because flame retardance cannot be obtained, and if the amount exceeds 200 parts by weight, processability deteriorates, so we selected an optimal range with a good balance between flame retardancy, processability, and crosslinking.In addition, silane grafted polyolefin resin 5 ~80 parts by weight, 5 to 40 parts by weight of carbon black, 2 to 50 parts by weight of red phosphorus resin (fuel agent) because if the amount of silane-grafted polyolefin resin is too large, processability will be poor, and if it is extremely small, it will not be desirable. This is because the degree of crosslinking cannot be obtained.Furthermore, the reason for adding a predetermined amount of carbon black and red phosphorus flame retardant to the silane-grafted polyolefin resin is to keep the viscosity at the same level as the aforementioned polyolefin resin mixture. Here, metal hydrates are released in the event of a fire, etc.
The temperature rise is suppressed by a mechanism involving an endothermic reaction that releases crystal water, and the carbon black itself carbonizes and remains, and the red phosphorus flame retardant dehydrates the polyolefin resin through its dehydration reaction, promoting carbonization of the resin. It has an effect.

′ <Function> As described above, by using flame retardants and base rubbers and plastics that do not contain halogen elements, they are flame retardant, do not generate toxic gases, are highly safe, and are resistant to corrosion. There is no fear.

In addition, since the frame barrier layer 5 has a structure made of an inorganic tape material, a metal tape material, a flame-retardant tape material, or a combination thereof, the heat resistance, flame retardance, air resistance, etc. of these tapes are Due to the synergistic effect, the layer 5 itself has good heat resistance, and even if this layer itself is exposed to fire, it will not be easily damaged, and therefore the heat transfer and air supply to the inside of the cable core will be effective. cut off,
The inside of the core is well protected. Further, the carbonized tape layer 6 immediately below this layer 5 is also carbonized extremely well. Therefore, even if the insulator 2 inside the core melts due to an increase in the temperature of the cable, the resin will not flow to the outside due to the carbonization and interaction with the carbonized tape layer 6, which forms a kind of unglazed wall. Almost completely prevents leaching. Further, the barrier protection layer 7 provided on the frame barrier layer 5 strongly protects and reinforces the frame barrier layer 5 against mechanical external forces, etc., and also has low heat transfer properties due to the material, so it can prevent fires. In such cases, by thermally protecting the barrier layer 5, the sheath 8
It works to suppress the temperature rise. Further, since the sheath 8 is cross-linked with silane, the heat resistance and cold resistance of the sheath 8 itself are improved. In addition, the sheath is mixed with carphone black and, if necessary, a red phosphorus flame retardant, so carbonization occurs smoothly in the event of a fire, and the inside of the core is protected.

Note that the insulator 2, the intervening material 4, and the sheath 8 may include, if necessary,
Other additives such as anti-aging agents, lubricants, coupling agents for treating fillers, catalysts for promoting crosslinking, etc. can also be added.

Furthermore, although the above description has been made regarding multi-core cables, the present invention is of course applicable to single-core cables as well.

<Example> Next, each embodiment of the cable according to the present invention (No.

1 to 24) are shown in Table 1. In addition, comparative examples (patients 1 to 4) are shown for comparison.

Further, in the silane crosslinked sheath of the present invention, examples (Nα25 to 34
) was created. Regarding this, comparative example (1'h5~1
0) was produced. .

Each example in Table 1 and Table 2 above (No. 1 to 34)
As is clear from the above, the cable according to the present invention generates little smoke and does not generate toxic and corrosive gases such as hydrogen chloride gas. Moreover, it is also found that it has sufficient flammability. In addition, the properties of the sheath are also excellent. On the other hand,
In the case of conventional cables according to comparative examples (Nα1 to 10), the flame retardance was poor, a lot of smoke was generated, and when hydrogen chloride gas was generated, the concentration was dangerous to the human body.
The concentration was sufficient to corrode the contacts of nearby electrical equipment. Furthermore, the sheath had poor extrudability and was unsatisfactory.

<Effects of the Invention> According to the present invention, as is clear from the above description, non-halogen rubber,
In addition to using a plastic stock, a sheath with silane crosslinking is used, and a cable ((in the Y structure, outside the insulated wire core or outside the insulated wire core bundle made by twisting these wires, A nonflammable inorganic tape material mainly made of ceramic, or a metal tape material, or a flame retardant tape material mainly made of an organic material with an oxygen index value of 35 or more, or at least two types of tape materials stacked together. If necessary, a barrier protection layer made of asbestos, glass, etc. tape is provided on the outside of this layer, or a carbonized tape layer that is carbonized by heating is provided on the inside of the frame barrier layer. Therefore, it is possible to provide a flame-retardant cable that has excellent TEIE flammability and heat resistance, does not generate toxic gas, and is designed to be clean with less smoke when burned.Especially Since it is based on silane cross-linking, there is no need for large-scale cross-linking equipment, making it highly economical. Also, since the flame barrier layer mentioned above reduces the burden of flame retardancy on the sheath, it has excellent mechanical properties and good processability. By protecting the sheath, the frame barrier layer, etc., it is possible to use an insulator that emphasizes its original electrical properties.

[Brief explanation of the drawing]

1 to 4 are longitudinal cross-sectional views showing each example of the flame-retardant cable according to the present invention. DESCRIPTION OF SYMBOLS 1... Conductor, 2... Insulator, 5... Frame barrier layer, 6... Carbonized tape layer, 7... Barrier protection layer,
8...Sheath. Figure 1

Claims (5)

[Claims] (1) On the outside of an insulated wire core with an insulator of rubber or plastic (excluding those containing halogen elements) on the conductor, or on the outside of an insulated wire core made of these twisted together, Non-flammable inorganic tape materials mainly made of ceramics, or metal tape materials, or flame-retardant tape materials mainly made of organic materials with an oxygen index value of 35 or more,
Alternatively, 50 to 200 parts by weight of a metal hydrate is added to a frame barrier layer formed by laminating at least two types of tape materials, and 100-X parts by weight of polyolefin resin (excluding those containing halogen elements). The added polyolefin resin mixture contains X parts by weight of a silane-grafted polyolefin resin (X is 5 to 80) and 5 to 40 parts by weight of carbon black or 2 to 40 parts by weight of a red phosphorus component.
A silane-crosslinked sheath formed by mixing a silane-grafted polyolefin resin mixture (excluding those containing halogen elements) with 50 parts by weight of a red phosphorus flame retardant. Flammable cable. (2) The flame-retardant cable according to claim 1, characterized in that 5 to 40 parts by weight of carbon black is mixed into the polyolefin resin mixture. (3) A red phosphorus flame retardant having a red phosphorus component of 2 to 50 parts by weight is mixed into the polyolefin resin mixture, as set forth in claim 1 or 2. flame retardant cable. (4) The flame-retardant cable according to claim 1, 2, or 3, characterized in that a carbonized tape layer that is carbonized by heating is provided inside the frame barrier layer. (5) Claims 1, 2, 3, or 4 further include a barrier protection layer provided outside the frame barrier layer to protect the frame barrier layer.
Flame-retardant cables as described in section.