JPH01236517A - Flame-retardant wires and cables - Google Patents

Abstract

PURPOSE:To improve fire resistance and prevent generation of halogen gas poisonous upon combustion by forming a covering layer made of a specified composition around the outer periphery of an insulated wire core. CONSTITUTION:A covering layer is formed on the outer periphery of an insulated wire core. The layer is made of a composition including 1wt. part or more of carbon black having average particle dia. of 80mum or less as well as 50-300wt. part of aluminium hydroxide. As such polyolefine, low density polyethylene, straight chain-shaped low density polyethylene and the like may be used. It is thus possible to provide wires and cables which generates no poisonous halogen gas at the time combustion and is excellent in fire resistrance.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides flame-retardant wires and cables that do not generate toxic halogen gas when burned, especially wires and cables that pass the fire resistance test of Fire and Disaster Management Agency Notification No. 7. It is related to.

[Conventional technology]

Recently, emergency alarm equipment has been installed in high-rise buildings such as buildings, power plants, various plants, etc., assuming that fires do not occur.
There is a strong demand for flame-retardant wires and cables that do not generate halogen gases and have good fire resistance properties for cables installed in smoke exhaust equipment, indoor fire hydrant equipment, etc.

Conventionally, the only flame-retardant electric wires and cables with fire-resistant properties were those with sheaths made of polyvinyl chloride, chlorinated polyethylene, or the like.

[Problems to be Solved by the Invention] However, there is a problem in that these cables generate a large amount of halogen gas when burned, which significantly impedes evacuation and firefighting activities.

The present invention has been made in view of the above circumstances, and its purpose is to provide flame-retardant wires and cables that do not generate toxic halogen gas when burned and have good fire resistance properties. be.

[Means and effects for solving the problems] The gist of the present invention is to prepare 5 to 300 parts by weight of surface-treated aluminum hydroxide and 100 parts by weight of a halogen-free polyolefin having a crystal melting point of 90°C or higher Average particle size 80mμ
A coating layer made of a composition containing 1 ffiffi part or more of the following carbon black is formed on the outer periphery of the insulated wire core.

In the present invention, examples of the non-containing polyolefin having a crystal melting point of 90° C. or higher include low density polyethylene, linear low density polyethylene, ultra low density polyethylene, ethylene vinyl acetate copolymer, ethylene ethyl acrylate copolymer, Examples include ethylene methyl acrylate copolymer.

If the crystal melting point (peak temperature when measured with a differential scanning calorimeter) is not 90° C. or higher, thermal deformation during use will be large, which is undesirable.

The surface-treated aluminum hydroxide and minilam must be contained in a range of 50 to 300 parts by weight per 100 parts by weight of the polyolefin; if it is less than 50 parts by weight, sufficient flame retardancy cannot be imparted to the polyolefin; If the amount exceeds 300 parts by weight, the mechanical properties will significantly deteriorate. The aluminum hydroxide used must be surface-treated with a fatty acid, a fatty acid metal salt, a silane coupling agent, a titanate coupling agent, etc., and if untreated, water resistance will be significantly reduced.

It is necessary to use carbon black with an average particle size of 80 mμ or less, and if it exceeds this, the fire resistance performance will be significantly reduced. Carbon black is polyolefin 100
It is necessary to add one or more parts by weight, and if it is less than 1 part by weight, no effect of improving flame retardancy will be observed.

In addition to the above components, the present invention also contains antioxidants, lubricants,
A softener, a dispersant, etc. may be added as appropriate.

[Example] As shown in the table, various components were put into a 12-inch roll maintained at 130° C. according to the blending ratio, and roll kneading was performed to prepare a sheath composition.

Next, a thickness of 0.15 was applied to the outer periphery of the copper conductor with a cross-sectional area of 2III12.
Wrap 1 mm mica tape and place 1 piece of polyethylene on top of it.
．． A pressing tape is wound around the outer periphery of two insulated wire cores coated to a thickness of 100 ml, and the above sheathing composition is applied on top of the tape to a thickness of 1.
．． 5. Various cables were produced by extrusion coating. Various performance tests were conducted on these cables as described below.

Flame retardancy test: Based on the slope test of JIS C3005 (rubber/plastic insulated wire testing method), length 300
The cable in (■) was tilted 60" from the horizontal and a burner flame was applied for 30 seconds at a position 20a+m from the bottom end. If the flame goes out within 60 seconds after removing the burner, it passes; if it lasts longer than 60 seconds, it passes. And so.

Fire resistance test: In accordance with Fire and Disaster Management Agency Notification No. 7, the cable fixed in the pipe was heated using a temperature curve according to JIS A 1302 (fire protection test method for noncombustible structural parts of buildings), and the insulation resistance after 30 minutes was determined. , AC 1500V
A withstand voltage test was conducted by applying a voltage of 1 minute. The criteria for judgment were that those with insulation resistance of 0.4 MΩ or more and that could withstand the withstand voltage test passed, and those that did not satisfy these criteria failed.

Heat deformation test: According to JIS C3005 (Rubber/Plastic Insulated Wire Test Method), using a sheet cut from a cable, the heat deformation rate after applying a load of 1530 g for 30 minutes at 75°C was JIS C3605 (600V
(polyethylene cable), 10% or less was considered to be passed, and anything exceeding this was judged to be rejected.

As is clear from the table, Examples 1 to 6 all passed the fire resistance test and showed good results in the flame retardancy test and heat deformation test.

On the other hand, Comparative Example 1 contained no aluminum hydroxide.
i is less than the specified value, and in Comparative Example 2, the carbon black content is less than the specified value, and both have insufficient flame retardancy. Moreover, in Comparative Example 2, the crystal melting point of the polyolefin was less than the specified value, and the sample failed the heat deformation test. Furthermore, in Comparative Examples 3 and 4, the particle size of carbon black exceeded the specified value, and the samples failed the fire resistance test.

[Effects of the Invention] As explained above, according to the present invention, it has excellent fire resistance properties,
Moreover, it is possible to provide flame-retardant wires and cables that do not generate toxic halogen gas when burned.

Claims (1)

[Claims] 1. 50 to 300 parts by weight of surface-treated aluminum hydroxide and an average particle size of 80% per 100 parts by weight of a halogen-free polyolefin with a crystal melting point of 90°C or higher.
A flame-retardant electric wire/cable, characterized in that a coating layer made of a composition containing 1 part by weight or more of carbon black of mμ or less is formed on the outer periphery of an insulated wire core.