JPS6077314A - 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, the drawbacks of polyvinyl chloride resin compositions containing aluminum hydroxide are that the initial insulation resistance is low and that the leverage properties are further significantly degraded due to moisture absorption and 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 due to the fact that there are some remaining. 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 is a polyvinyl chloride resin composition containing aluminum hydroxide and having an average particle size of 10 μm or less and whose surface is treated with a hydrophobic and/or water-repellent compound. It is characterized in that it is provided as an insulator around the conductor or as 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 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 average particle size of lθμ or less, and is a special hydroxylated resin whose surface is treated with a hydrophobic and/or water-repellent compound. The reason is that aluminum is used. Treating the surface of aluminum hydroxide with a hydrophobic and/or water-repellent compound suppresses the diffusion of a considerable amount of electrolyte, thereby suppressing the initial electrical properties and the deterioration of electrical properties due to moisture absorption and water absorption. The main objective is to improve processability, surface appearance, and physical properties.

Compounds having hydrophobic properties 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 may be of some degree, but it is determined according to 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, decrease in physical properties, etc., and furthermore, it is possible to prevent wear of the metal during kneading and extrusion.

The amount of special aluminum hydroxide added is not particularly limited, but
A suitable 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, a high degree of flame retardancy cannot be imparted, and if it exceeds 150 parts by weight, the physical properties as a mis-insulating material will deteriorate.

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, polyfunctional monomers are added, free radical generators and energy
It is also possible to apply cross-linking to create a three-dimensional structure using a punch wire to improve heat deformation resistance and other properties.

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 100 parts by weight - I) Or' (dioctyl phthalate-1-) 50 parts by weight - Tribasic lead sulfate 10ffi parts - Lead stearate 1 part by weight - Calcined A resin composition consisting of 10 parts by weight of Relay, 2 parts by weight of antimony dioxide, and 60 parts by weight of aluminum hydroxide (average particle size of 5 μm, surface treated with 1% vinyl silane) was applied to the outer periphery of a copper conductor with a cross-sectional area of 3.5+++v/. An electric wire was prepared by extrusion coating to a thickness of 0.811III+.

After this electric wire was immersed in water at 30° C. for 1 hour, the insulation resistance was measured and found to be 0.91 megtoms/kts.

Insulation resistance after being submerged in water at 30℃ for 1000 hours is 0.2
It was 1 mektom/,'km.

The appearance of the wire is shiny, and the elongation in the tensile test is 30
0%, which showed excellent properties. In addition, two electric wires with a length of 1 m are
Place it on a 5mmφ oak stick, hold both ends with both hands, and press it for 10 minutes.
After going back and forth several times, the appearance was just that there were very slight white streaks.

Next, place the wire in the right direction, and the height of the inner flame will be 50III!
, Bunsen burner flame with external flame height 100III11 4
As a result of 3 cycles of 30 seconds of flame contact and 30 seconds of flame removal at an angle of 5 degrees, almost no spread of fire was observed in any of the cycles, demonstrating excellent flame retardancy.

Comparative Example An electric wire was produced in the same manner as in Example 1, except that untreated aluminum hydroxide with an average particle diameter of 30 μm was used.

After this electric wire was immersed in water at 30° C. for 1 hour, the insulation resistance was measured and found to be 0.11 meqohm/lv.

Insulation resistance after immersed in water at 30℃ for 1000 hours is 0.0
It was 1 mektom/km.

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

In addition, after placing a 1 m long electric wire on a 2511111φ oak rod and moving it back and forth 10 times while holding both ends with both hands, the surface became 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 fines containing special aluminum hydroxide, thereby improving electrical properties. It has excellent physical properties such as
Moreover, electric wires and cables having a high degree of flame retardancy can be obtained.

5 cho Address 1 Hitachi Cable Co., Ltd. Electric Wire Research Institute

Claims (1)

[Claims] (1) A polyvinyl chloride resin separate product containing aluminum hydroxide with an average particle size of 10μ or less and whose surface has been treated with a hydrophobic and/or water-repellent compound is used as an insulator around the conductor or outside the insulator. An electric wire φ cable characterized in that it is provided as a circumferential sheath.