JPS6077313A - Flame resistant wire and 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 [Background and Objectives of the Invention] The present invention relates to flame-retardant wires and cables that have high flame retardancy and excellent electrical properties.

It has been common practice to make various polymers flame retardant by utilizing the endothermic reaction caused by the dehydration of large amounts of crystallized water in aluminum hydroxide.

Soft polyvinyl chloride is no exception; aluminum hydroxide is added to make it highly flame retardant.

However, a disadvantage of polyvinyl chloride resin compositions containing aluminum hydroxide is that the initial insulation resistance is low and that this property is further significantly degraded by moisture absorption or water absorption.

Insulation resistance is the most fundamental characteristic of the insulation and sheath of electric wires and cables, and it is a serious problem that this resistance is low from the beginning, and that it decreases significantly due to moisture absorption and water absorption during practical use.

Until now, it has been thought that aluminum hydroxide is inherently inferior in insulation resistance, and that as long as aluminum hydroxide is used, no improvement in insulation resistance can be expected. The reason for this is that caustic soda is used in the production of aluminum hydroxide.
This is thought to be because o etc. remain. In particular, when such an electrolyte is located near the surface of the particle, the properties seem to deteriorate more than when it is inside the particle.

The present invention solves the above-mentioned drawbacks of the prior art, and
The object of the present invention is to provide electric wires and cables having an insulator or sheath with improved electrical properties, particularly insulation resistance.

[Summary of the Invention] The electric wire/cable of the present invention has a water immersion liquid conductivity of 100 microt/cm or less and an average particle size of 10 μ or less, and the surface is treated with a compound having hydrophobicity and/or water repellency. The present invention is characterized in that a polyvinyl chloride resin composition containing aluminum hydroxide is provided as an insulator around the conductor or a sheath around the insulator.

In the present invention, polyvinyl chloride includes not only homopolymers but also copolymers mainly composed of vinyl chloride,
For example, vinyl chloride and ethylene-vinyl acetate, ethylene-
A graft copolymer of ethyl acrylate, chlorinated polyethylene, polyurethane, etc., or a copolymer of vinyl chloride, ethylene, propylene, vinyl acetate, etc. may also be used.

The important point in the present invention is that as a filler that improves the flame retardancy of polyvinyl chloride resin, it has an immersion liquid conductivity of 1100 micromho/cII+ or less, an average particle size of loμ or less, and a hydrophobic and The point is that special aluminum hydroxide treated with/or a water-repellent compound is used. Since the electrolyte substance has been removed from such special aluminum hydroxide, a polyvinyl chloride resin composition containing this special aluminum hydroxide has excellent insulation resistance. Furthermore, by treating the surface with a hydrophobic and/or water-repellent compound, higher insulation resistance can be achieved. This surface treatment makes it possible to suppress the diffusion of electrolyte, which is still present in considerable amounts.

Compounds having hydrophobicity and/or water repellency include:
Examples include fatty acids such as stearic acid, various titanate coupling agents, and various silane coupling agents. The degree of treatment of the aluminum hydroxide surface is 1% of these compounds.
It should be determined depending on the required characteristics and is not particularly limited. These compounds may be diluted with a suitable solvent, dispersant, etc., dry-treated by spraying or the like, and then heat-treated.

Further, by controlling the average particle size to 10 μm or less, it is possible to prevent roughness in appearance, decrease in wear resistance, and decrease in other physical properties, and furthermore, it is possible to prevent wear of the metal during kneading and extrusion.

The method to obtain special aluminum hydroxide is to remove electrolyte substances during the aluminum hydroxide manufacturing process.
Specifically, reprocessing such as washing with water, dehydration, and drying is an effective means.

The amount of special aluminum hydroxide added is not particularly limited, but
The appropriate amount is 10 to 150 parts by weight per 100 parts by weight of polyvinyl chloride; if it is less than 10 parts by weight, high flame retardancy cannot be imparted, and if it exceeds 150 parts by weight, the physical properties of the electrical insulation 90 will deteriorate.

In the present invention, the conductivity of immersed liquid is measured by placing 40 g of aluminum hydroxide in a glass beaker made of non-alkali glass, adding 200 cc of boiling distilled water, boiling for 10 minutes, and cooling.
Add water until it reaches 0 cc, stir well, and filter 1°. This filtrate is transferred to a platinum electrode container, and the electrical conductivity is measured at 25° C.±0.5° C. using an AC bridge. Incidentally, the conductivity of the distilled water used here must be 3 microts 1 CI11 or less.

In the present invention, in addition to the polyvinyl chloride and special aluminum hydroxide, plasticizers, stabilizers, lubricants, flame retardants, fillers, antioxidants, colorants, etc. may be added. Furthermore, it is also possible to add a polyfunctional monomer and apply a free radical generator or an energy-rich beam to create a three-dimensional crosslinking structure, thereby improving anti-deformation properties and the like.

The composition thus obtained is used as an insulator around the conductor,
Furthermore, by using it as a sheath around the insulator, wires and cables with excellent electrical properties can be realized.

[Examples and Comparative Examples] Examples/Polyvinyl chloride 1003X [ffi part/DO'P(
Dioctyl phthalate)) 50 parts by weight J 1 part by weight Tribasic lead sulfate 1 part by weight Lead stearate 10 parts by weight Calcined clay 2 parts by weight Antimony dioxide 60 parts by weight Aluminum hydroxide (Immersion liquid conductivity degree 85 microt/cm, average particle size 5μ
An electric wire was prepared by extrusion coating the outer periphery of a copper conductor having a cross-sectional area of 3.5 va with a resin composition consisting of a copper conductor (surface treated with vinyl silane) to a thickness of 0.8 mm.

After this electric wire was immersed in water at 30° C. for 1 hour, the insulation resistance was measured and found to be 1.7 MectA/km. 30
The insulation resistance after being immersed in water at ℃ for 1000 hours was 0.71 mectom/km.

The appearance of the wire is shiny, and the elongation in the tensile test is 30
0%, which showed excellent characteristics. Further, after placing an electric wire of 1 fTl in length on a 25 mm diameter oak rod and moving it back and forth 10 times while holding both ends with both hands, the appearance was only slightly white streaked.

Next, place the electric wire in the right position, and apply a Bunsen burner flame with an inner flame height of 50 nu++ and an outer flame height of 10.0 mm at an angle of 45 degrees for 30 seconds and then remove the flame for 30 seconds for 3 cycles. As a result, almost no spread of fire was observed in any cycle, demonstrating excellent flame retardancy.

Comparative Example An electric wire was prepared in the same manner as in Example 1, except that untreated aluminum hydroxide was used, having an immersion liquid conductivity of 15014 μ% -/cry and an average particle size of 20 μm.

After this electric wire was immersed in water at 30° C. for 1 hour, the insulation resistance was measured and found to be 0.10 Mekm/km.

Insulation resistance after immersed in water at 30℃ for 1000 hours is 0.0
It was Tsuyoshi in 09 Mektom/.

The electric wire had a rough, shark-like appearance, and the elongation in the tensile test was 200% or less.

Also, place a 1m long electric wire on a 25mmφ oak rod,
After pressing both ends with both hands and reciprocating 10 times, the surface was noticeably whitened.

[Effects of the Invention] As explained above, the present invention provides electric wires and cables whose insulators or sheaths are made of polyvinyl chloride resin compositions containing special aluminum hydroxide. Excellent properties and other physical properties,
Moreover, it is highly flame retardant.Continued from page 1

Claims (1)

[Claims] (1) Is the immersion liquid conductivity 100? A polyvinyl chloride resin composition containing aluminum hydroxide, which has an average particle size of 10μ or less and whose surface is treated with a hydrophobic and/or water-repellent compound, is used as an insulator around the conductor. Or an electric wire/cable characterized by being provided as a sheath around the outer periphery of an insulator.