JPH0196251A - Flame retardant electrical insulation composition - Google Patents

Abstract

PURPOSE:To obtain the titled composition effective in suppressing the lowering of electrical properties caused by absorption of water and moisture, having excellent flame-retardance and suitable as an insulating material for wire and cable, etc., by fixing metal hydroxide to powdery resin or powdery rubber and compounding the product to a resin or a rubber. CONSTITUTION:A powdery metal hydroxide (e.g. aluminum hydroxide) is fixed to a powdery resin (e.g. polyethylene) or a powdery rubber (e.g. ethylene propylene rubber) having an average particle diameter of <=100mum. The average particle diameter of the metal hydroxide powder is <=1/10 of that of the powdery resin, etc. A resin or a rubber is compounded with >=50pts.wt. (in terms of metal hydroxide) of the fixed metal hydroxide.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention relates to a flame-retardant electrical insulating composition that can suppress deterioration of electrical properties due to water absorption and moisture absorption, particularly for use in insulating materials and sheath materials for electric wires and cables. The present invention relates to flame retardant electrical insulation compositions suitable for application.

[Prior Art] Resins or rubbers such as polyethylene, ethylene propylene rubber, polyvinyl chloride, and chloroprene rubber are often used as insulation materials and sheath materials for electric wires and cables.

As a recent trend, strong flame retardancy has become required for electric wires and cables for nuclear power plants, as well as electric wires for wiring inside panels and inside machines.

BACKGROUND ART As one method of making resin or rubber flame retardant, a technique of incorporating metal hydroxides has been attracting attention.

[Problems to be Solved by the Invention] However, metal hydroxides tend to absorb water and moisture, leading to a decrease in electrical characteristics.

An object of the present invention is to provide a flame-retardant electrical insulating composition that can prevent deterioration of electrical properties by suppressing water absorption and moisture absorption of metal hydroxides.

[Means for solving the problems] The flame-retardant electrical insulation composition of the present invention comprises resin or rubber,
Powdered resin or powdered rubber with an average particle size of 1000 μm or less, with an average particle size of 1/10 of these powdered resins or powdered rubber.
It is characterized by being made by mixing the following metal hydroxides with immobilization treatment.

In the present invention, immobilization treatment refers to stirring powdered resin or powdered rubber and metal hydroxide in a mill, thereby mechanochemically adhering the metal hydroxide to the surface of the powdered resin or powdered rubber, and then finely pulverizing the powdered resin or powdered rubber. This refers to the process of driving and fixing metal hydroxide into powdered resin or powdered rubber using the impact force and frictional force of a machine, etc. In this way, by immobilizing with hydrophobic resin or rubber, water absorption and moisture absorption can be suppressed. In addition, the immobilization treatment can suppress aggregation of metal hydroxides and improve dispersibility.

Powder resins used in the immobilization treatment include polyolefins such as polyethylene, polypropylene, polybutene-11 ethylene-vinyl acetate copolymer, ethylene ethyl acrylate copolymer, ethylene methyl acrylate copolymer, ethylene butene-1 copolymer, and ethylene butene-1 terpolymer; Nylon 6, Nylon 11, Nylon 1
2. Polyamide resins such as nylon 610, polytetrafluoroethylene, polychlorotrifluoroethylene, tetrafluoroethylene hexafluoropropylene copolymer, tetrafluoroethylene perfluorovinyl ether copolymer, ethylene fluoroethylene copolymer, polybutsu Fluororesins such as vinyl chloride, polyvinylidene fluoride,
Examples include vinyl chloride resin, vinylidene chloride resin, chlorinated polyethylene resin, polystyrene resin, polymethyl methacrylate resin, phenol resin, acrylonitrile butadiene styrene resin, and the like. Furthermore, polycarbonate, acetal resin, epoxy resin, polyester,
Engineering plastics such as polyphenylene oxide, polyimide, polyamideimide, polyarylate, and polyetheretherketone can also be used.

Powdered rubbers include ethylene propylene rubber, styrene butadiene rubber, butyl rubber, natural rubber, chloroprene rubber, chlorosulfonated polyethylene, nitrile rubber, evichlorohydrin rubber, silicone rubber, fluoro rubber, urethane rubber, norbornene rubber, etc. can be given. Further examples include olefin-based, styrene-based, fluorine thread, urethane-based, ester-based, amide-based, and vinyl chloride-based thermoplastic elastomers.

Note that it is preferable to use polyolefin, which has excellent electrical properties, as the insulating material.

These powdered resins or powdered rubbers have an average particle size of 1000
It is necessary to use a material with a diameter of .mu.m or less; if it is larger than this, the immobilization process becomes difficult.

Hydroxic acid (
Examples include hyaluminum, magnesium hydroxide, basic magnesium carbonate, calcium hydroxide, barium hydroxide, hydrotalcite, and the like. The average particle size of the metal oxide must be one-tenth or less of the average particle size of the above-mentioned powdered resin or powdered rubber, and if it exceeds this, the immobilization process becomes difficult.

The immobilized product obtained as described above is mixed with resin or rubber, but as this resin or rubber,
The same materials as the above-mentioned powdered resins and powdered rubbers can be mentioned, and they can be used alone or in combination of two or more kinds. In this case, the resin or rubber into which the immobilized material is mixed does not necessarily have to be of the same type as the powdered resin or powdered rubber, and may be in the form of powder, liquid, pellet, bulk, or block. But that's fine.

There are no particular limitations on the amount of the immobilized material (2) mixed into the resin or rubber, but in order to have a significant effect on improving flame retardancy, it is desirable to add 50 parts by weight or more in terms of metal hydroxide.

In the present invention, in addition to the above components, crosslinking agents, flame retardant aids, antioxidants, lubricants, softeners, dispersants, etc. may be used as appropriate.

[Example of the invention] Various ingredients were mixed into 100% according to the blending ratios shown in Table 1.
The mixture was put into a 6-inch roll kept at 120°C for roll kneading.
L/D=25) was used to extrude coat a copper wire with an outer diameter of 2.0 mm to a thickness of 1.0 mm to produce an insulated wire. In addition,
For Examples 1 to 4 and Comparative Examples 1 to 3, crosslinked insulated wires were manufactured by holding the wires in a steam atmosphere of 13 kg/cm<2> for 3 minutes after extrusion coating.

For immobilization treatment of various metal hydroxides, Nara Kikai Seisakusho (
Using 0M Dizer 10 and Hybridizer 1 from Co., Ltd.,
The powdered resin or powdered rubber and metal hydroxide were stirred for 10 minutes using OM Dizer 1O to adhere the metal hydroxide to the powder resin surface, and then treated with Hybridizer 1 for 6 minutes to fix it.

The results of evaluating the insulation resistance and flame retardance of the insulated wires of Examples and Comparative Examples are shown in the lower column of Table 1.

The evaluation was based on the following.

Flame retardancy: Based on JISC3004, if the insulated wire held horizontally is burned in a burner, it passes if it disappears within 1 minute, and if it burns for more than 1 minute, it is rejected.

Insulation resistance: Dry each sample at 80°C for 24 hours, then
For items left in water at 5℃ for one month, JISC3
Measured based on 004.

*1 Mouni viscosity ML, (100°C) 40, ethylene amount 70mo1%, propylene amount 30mo1% *2 Mouni viscosity ML, (100°C) 35, ethylene amount 7
0 mo1%, propylene amount 29 mo1%, ethylidene norbornene amount 1 mo 1% *3 Melt index (190°C) 1.5, vinyl acetate content 12% by weight *4 Melt index (190°C) 1.5, Ethyl acrylate content 19% by weight *5 Average particle size 1 μm 1 No treatment *6 Average particle size ■ 2 μm powder polyethylene/average particle size 1
Immobilization treatment with a ratio of aluminum hydroxide in μm = 60/40 (7) *7 Average particle size 0.4 μm 1 No treatment *8 Powdered polyethylene with an average particle size of 5 μm / Average particle size 0.
Immobilization treatment at a ratio of 4 μm magnesium hydroxide = 50150 As is clear from Table 1, Examples 1 to 6 according to the present invention all passed the flame retardancy test and showed good performance even after being immersed in water for one month. Indicates insulation resistance. On the other hand, in Comparative Example 1, in which no metal hydroxide was mixed, the flame retardance was rejected, and in Comparative Examples 2 and 3, in which metal hydroxide was not immobilized, the insulation resistance decreased significantly. .

[Effects of the Invention] As explained above, the present invention involves immobilizing metal hydroxide in powdered resin or powdered rubber and mixing it with resin or rubber, which has excellent flame retardancy, water absorption,
It becomes possible to suppress deterioration of electrical characteristics due to moisture absorption.

Claims (1)

[Claims] (1) A product obtained by immobilizing a metal hydroxide with an average particle size of 1/10 or less of that of the powdered resin or powdered rubber on a resin or rubber with an average particle size of 1000 μm or less. 1. A flame-retardant electrical insulating composition, characterized in that it is made by mixing.