JPH05305688A - Fire retardant molded article - Google Patents

Abstract

PURPOSE:To enhance methanical strength, in a tube having inner and outer layers composed of a resin compsn. containing halogen in a predetermined ratio, by forming the inner layer from a resin based on polyolefin and forming the outer layer from specific engineering plastic. CONSTITUTION:In a non-halogen fire retardant electric wire or tube consisting of inner and outer layers composed of a resin compsn. containing halogen in an amount of 1 pts.wt. or less per 100 pts.wt. of the compsn., an inner polyolefin fire retardant layer 2 is composed of a resin compsn. prepared by compounding 50-250 pts.wt. of a metal hydrate with 100 pts.wt. of polyolefin and having an OI value (limit oxygen index) of 25 or more and an outer engineering plastic layer 3 is made of engineering plastic with an OI value of 25 or more. With respect to an electric wire A, a conductor 1 is coated with a composite insulating layer consisting of inner and outer layer 2,3. By this constitution, abrasion resistance at high temp., mechanical strength and oil resistance can be enhanced and, even when the outer layer 3 is dropped at the time of combustion, the inner layer 2 is protected by the formation of a shell.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to non-halogen flame retardant tubes or wires.

[0002]

2. Description of the Related Art Generally, flame retardation of a polymer can be easily achieved by blending a halogen compound.
In recent years, a toxic gas generated at the time of burning halogen compounds has become a problem. Therefore, a method of blending a metal hydrate with a polymer has been adopted as a non-halogenation method. In this case, metal hydrates such as aluminum hydroxide and magnesium hydroxide have been blended with polyolefins such as polyethylene and ethylene-based copolymers.

However, if the compounding amount is increased in order to increase flame retardancy, it is difficult to obtain mechanical strength and heat resistance, and as a resin to be used, such as low-density polyethylene and ethylene-based copolymer, filling is performed. Since a polymer that can be mixed with many materials is used, mechanical strength, heat resistance, chemical resistance, etc. are not sufficient. Further, since these polymers are softened at about 100 ° C., they are difficult to use in applications requiring mechanical strength at high temperatures.

On the other hand, when engineered plastic is used, for example, when it is placed in a tube and burned, flame retardancy is obtained but resin drips during burning,
It is disadvantageous for forming a protective layer. Also, this single layer of engineered plastic needs to be thicker,
The cost of tubes and wires will increase, and the flexibility will become insufficient.

[0005]

Means for Solving the Problems As a result of various studies on the above problems, the present inventors have found that an OI value (limit oxygen index) of 25 or more in which a metal hydrate is blended with a polyolefin is applied to the inner layer.
Mechanical strength, by using a composite layer tube or wire consisting of an outer layer of engineering plastic with a value of 25 or more,
The inventors have found that heat resistance, chemical resistance, flame retardancy, etc. can be further improved, and have completed the present invention.

That is, the present invention provides a tube comprising inner and outer layers having a halogen content of 1 part by weight or less with respect to 100 parts by weight of a resin composition, and 50 parts by weight or more of a metal hydrate with respect to 100 parts by weight of a polyolefin. An inner layer containing 250 parts by weight or less and an OI value of 25 or more, and an OI value of 2
A composite tube made of an outer layer of an engineering plastic of 5 or more and a composite electric wire using the same.

The present invention will be described in detail below with reference to the drawings. 1 and 2 are schematic views showing the cross-sectional structures of an electric wire A and a tube B according to the present invention, respectively. In FIG. 1, a conductor 1, a polyolefin flame-retardant layer 2 as an inner layer,
A composite electric wire A including an engineering plastic layer 3 as an outer layer is shown. FIG. 2 shows a composite tube B having a polyolefin flame-retardant layer 2 as an inner layer and an engineering plastic layer 3 as an outer layer.

The composite resin layer constituting the composite tube or the composite electric wire of the present invention needs to be an inner and outer layer containing 1 part by weight or less of halogen with respect to 100 parts by weight of the resin composition. When the halogen content in the resin composition exceeds 1 part by weight, the advantage of non-halogen is lost and the intended purpose cannot be sufficiently achieved. In the present invention, the inner layer contains 50 to 250 parts by weight of metal hydrate in 100 parts by weight of polyolefin.
Parts by weight, preferably 70 to 150 parts by weight,
It is important that the I value is 25 or more, preferably 30 or more.

If the amount of the metal hydrate added in the inner layer is less than 50 parts by weight, the desired flame retardancy cannot be imparted, and
It also has a drawback that the OI value becomes 25 or less and the flame retardancy in ordinary air is greatly reduced. If it is added in an amount of more than 250 parts by weight, the water resistance will be significantly reduced and the mechanical strength will be impaired. Examples of the metal hydrates include aluminum hydrates and magnesium hydrates, and the use of magnesium hydrates is particularly preferable from the viewpoint of high flame retardancy. The metal hydrate may be used as it is, or may be surface-treated with a silane or titanate coupling agent or the like.

The polyolefin resin is not particularly limited, and examples thereof include polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer ethylene-ethylene acrylate copolymer, ethylene-methyl methacrylate and the like. it can.
In order to obtain flame retardancy in this inner layer, as a flame retardant aid,
For example, a phosphorus compound, an amine compound, or a silicone compound may be blended. Although the level of flame retardancy varies depending on the application such as slow flame retardancy and flame retardancy, the inner layer preferably has an OI value of at least 25 or more in order to be called flame retardant.

The resin constituting the outer layer has an OI value of 2
It is necessary to use 5 or more, preferably 30 or more engineering plastics. Such a specific O
By using an engineering plastic having an I value, it is possible to compensate for the heat resistance of the polyolefin flame-retardant layer having a low softening point, and it is effective in achieving an OI value of 25 or more from the aspect of flame retarding the resin composition. is there.

As an engineering plastic,
Those having an OI value of 25 or more are desirable, for example, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyarylate, polysulfone, polyether sulfone, polyphenylene sulfide, polyether ether ketone, polyetherimide, polyimide, liquid crystal polymer, Polymers such as aromatic polyamide and nylon can be used.

In order to improve the heat resistance, mechanical strength, oil resistance and the like of the inner and outer layers, a composition having a crosslink may be used in some cases. In order to impart cross-linking to the insulating layer, a cross-linking agent or the like is added to the resin composition, and after molding,
Chemical cross-linking by heat, light or the like or cross-linking by ionizing radiation can be performed.

The heat-shrinkable tube can also be obtained by radially deforming the tube crosslinked by irradiation at a temperature equal to or higher than the glass transition point, for example, expanding and stretching by applying internal pressure. Upon crosslinking, a polyfunctional monomer such as triallyl cyanurate or triallyl isocyanurate can be used as a crosslinking aid. The resin composition of the present invention includes an antioxidant, a UV inhibitor, a lubricant,
You may mix | blend various additives, such as a pigment.

[0015]

In the present invention, by adopting the above-described composite structure, wear resistance at high temperature, mechanical strength, oil resistance, etc. are increased, and even if the outer layer drips during combustion,
The inner layer is protected by shelling. Furthermore, by setting the thickness of the inner layer necessary for protection, the thickness of the engineering plastic of the outer layer can be reduced, and the flexibility and material cost can be reduced as compared with the case of the engineering plastic alone.

[0016]

Example: The composite structure has an inner layer with an inner diameter of 5 mm and a wall thickness of 1 m.
m, the inner diameter of the outer layer was 7 mm, and the wall thickness was 0.1 mm. The single layer of the comparative example had an inner diameter of 5 mm and a wall thickness of 1 mm. (1) 100 parts by weight of an ethylene vinyl acetate copolymer having a vinyl acetate content of 25% is mixed with 100 parts by weight of magnesium hydroxide to obtain an inner layer tube having an OI value of 28. The outer layer uses polyarylate (U polymer) with an OI value of 36,
It was a two-layer tube. By using the polyarylate as the outer layer, the abrasion resistance under the atmosphere of 100 ° C. was excellent, the mechanical strength was increased, and the outer layer was hardly affected by xylene and the like. (2) 100 parts by weight of low-density polyethylene was mixed with 100 parts by weight of magnesium hydroxide, an insulating layer having an OI value of 26 was provided, and then a composite insulating layer was prepared using 6,6-nylon having an OI value of 29 as an outer layer. It was By using 6,6-nylon as the outer layer, the abrasion resistance was dramatically increased, the mechanical strength was increased, and the xylene and MEK were less likely to be attacked.

[0017]

[Comparative example]

(1) 100 parts by weight of ethylene-vinyl acetate copolymer having a vinyl acetate content of 25% is mixed with 100 parts by weight of magnesium hydroxide to obtain a tube having an OI value of 28. It was inferior in abrasion resistance in an atmosphere of 100 ° C. and easily swollen by xylene and swelled. (2) When an electric wire having an OI value of 29, which was insulation-coated with 6,6-nylon, was burned, it drastically dropped, and the flexibility was poor.

[0018]

[Effects of the Invention] A mechanical strength, heat resistance, oil resistance, etc. are required by using a tube for insulation protection of a cable that does not generate halogen and requires non-halogen, or by using an electric wire having a non-halo compound structure. It is suitable for use in various fields.

[Brief description of drawings]

FIG. 1 is a schematic view showing the crossing of an electric wire according to the present invention.

FIG. 2 is a schematic view showing a cross section of the tube of the present invention.

[Explanation of symbols]

 1 conductor 2 polyolefin flame retardant layer 3 engineering plastic layer

Continuation of front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location B32B 27/32 C 8115-4F F16L 11/04 7123-3J H01B 7/34 B 7244-5G // C08K 3 / 22 C08L 23/02 KEC 7107-4J

Claims (2)

[Claims] 1. A tube comprising inner and outer layers having a halogen content of 1 part by weight or less with respect to 100 parts by weight of a resin composition, and 50 parts by weight or more and 250 parts by weight or less of a metal hydrate with respect to 100 parts by weight of a polyolefin. A composite tube which is composed of an inner layer having an OI value of 25 or more and an outer layer of an engineering plastic having an OI value of 25 or more. 2. In an insulating layer consisting of inner and outer layers having a halogen content of 1 part by weight or less based on 100 parts by weight of a resin composition, 50 parts by weight or more and 250 parts by weight of a metal hydrate is added to 100 parts by weight of a polyolefin. Blended below, OI value is 2
A composite electric wire comprising an inner layer having a thickness of 5 or more and an outer layer of engineering plastic having an OI value of 25 or more.