JPH0644419B2 - Flame-retardant resin composition for electric wires and cables - Google Patents

Description

TECHNICAL FIELD The present invention relates to a flame-retardant resin composition used for a sheath of an electric wire / cable and an insulator for the insulating core wire, and particularly, a halogen-free flame-retardant resin composition. It relates to a flammable resin composition.

[Prior art and its problems]

As shown in the figure, the electric wire / cable P has a required number of insulating core wires 3 in which a conductor 1 is covered with an insulating material 2 and is provided with a jacket 4 on the outer circumference of the burning wires. 2, jacket 4
Vinyl chloride (PVC), polyethylene (PE),
Although ethylene propylene copolymers and the like are used, since all of them are flammable, a flame retardant is added to impart flame retardancy when kneading a composition containing these resins as a main component. ing.

As the flame retardant, there are phosphorus-based, halogen-based, and inorganic-based flame retardants, but the recent tendency is that harmful gases are generated when a fire occurs, so phosphorus-based and halogen-based flame retardants are shunned and non-halogenated. Has come to be required.

The flame retardant targeted for this non-halogenation is an inorganic type,
That is, it is a metal hydroxide such as magnesium hydroxide. In the case of this metal hydroxide flame retardant, when exposed to rain,
Carbon dioxide dissolved in water reacts with metal hydroxide,
The reaction product is an electric wire. It appears on the surface of the cable P, and a so-called whitening phenomenon occurs.

Although the reaction product itself does not directly affect the characteristics of the electric wire / cable P, it is not preferable because it lowers the commercial value. Further, even if there is no direct influence on the characteristics, the product may become a nucleus of dust accumulation on the surface of the electric wire / cable P, and as a result of dust accumulation, may cause tracking (creeping discharge). is there.

[Problems to be Solved by the Invention]

In view of the above, it is an object of the present invention to provide a flame-retardant resin composition that does not impair the commercial value of electric wires / cables and does not cause a reduction in tracking resistance.

[Means for Solving the Problems]

In order to solve the above problems, the present invention provides a flame-retardant resin composition that forms an insulator of the electric wire / cable, an outer cover,
(a), (b), (c) are mixed in the respective parts by weight range, the total amount of 100 parts by weight, the metal hydroxide 50 subjected to the surface dioleyl phosphate treatment or distearyl phosphate treatment. ~ 200 parts by weight and 0.5 to 4 of fatty acid metal salt
That is, at least one part by weight is mixed.

(a) Ethylene ethyl acrylate (EEA): 59-89
Parts by weight (b) low density polyethylene: 10 to 30 parts by weight (c) linear low density polyethylene or grafted product of ethylene ethyl acrylate and maleic anhydride: 1 to 20
Parts by weight The low-density polyethylene is an ultra-low-density polyethylene (V
LDPE) or chain low density polyethylene (LLDP)
E).

The fatty acids include both saturated and unsaturated.

A weather resistance-imparting agent, an antioxidant or a colorant can be added to the resin composition. This addition also includes mixing each agent appropriately.

[Action]

The mixed weight of EEA is determined by the mixed weight of LLDPE or VLDPE.
PE is added to EEA alone for the purpose of improving heat resistance, improving physical and mechanical properties, and enabling high filling of metal hydroxide, and is mixed beyond the above range. Then, kneading and extrusion processability are impaired. On the other hand, when the amount is small, physical, mechanical and heat resistance properties cannot be expected.

The grafted product of VLDPE and maleic anhydride or the grafted product of EEA and maleic anhydride serves as an adhesive resin, and enhances the compatibility of EEA and VLDPE with, for example, magnesium hydroxide, and is added to the composition. By improving the adhesiveness (capturing property) between the metal hydroxide and the resin, the deterioration of physical and mechanical properties is suppressed, and at the same time, the reaction between carbon dioxide gas and metal hydroxide is blocked, and the whitening phenomenon Suppress. When the content of the adhesive resin exceeds the above-mentioned compounding amount, the elongation becomes poor, and the tensile property shows no increase in the expansion force from the yield point to the break point. When the amount is small, the adhesion between the metal hydroxide and the resin deteriorates, the expansion force and elongation decrease, and the whitening preventing effect cannot be seen.

When the metal hydroxide exceeds the upper range, the metal hydroxide is stretched, the tensile strength is lowered, and the surface is treated with dioleyl phosphate or distearyl phosphate. By this treatment, the capture (adhesion) of the metal hydroxide by the adhesive resin is further ensured. This leads to an effect of preventing whitening in addition to an increase in expansion power.

The metal salt of saturated or unsaturated fatty acid is generally blended as a lubricant, but in the present invention, the purpose is to suppress the whitening phenomenon, and if it is blended in an appropriate amount, the wettability of the surface of the molded article decreases. Then, it is considered that water droplets containing carbon dioxide do not remain on the surface, and as a result, the whitening phenomenon is suppressed.

From the results of the study by the inventors, it is considered that the saturated or unsaturated fatty acid metal salt and the adhesive resin exert a synergistic effect within the above-mentioned certain range.

Therefore, in the present invention configured as described above, EEA, LLDPE, or VL is used as the base resin.
Since the adhesive resin of the grafted product of DPE and LLDPE and maleic anhydride is adjusted within the above range, the processability and kneading property are improved, and further the metal hydroxide is well dispersed in the resin composition, and It is firmly captured and the whitening phenomenon is prevented.

〔Example〕

When the insulator 2 and the jacket 4 of the electric wire / cable P shown in the drawing are formed by the resin composition according to the present invention (Examples 1 to 1)
8) and the experimental results of Comparative Examples not corresponding to the resin composition are shown in Table 1. Note that “↑” and “↓” in the table indicate above or below that value. The following products were used for EEA and the like.

EEA: NAC copolymer EEA WN-170 (Nippon Unicar) Adhesive resin A: Ubebond M1000 (Ube Industries) 〃 B: N polymer L6100M (Nippon Petrochemical) VLDPE: Yucaroncel X-138 (Mitsubishi Petrochemical) Mg (OH) ₂ : Average particle size 0.6 μm Surface dioleoyl phosphate treatment SLG: Lead stearate (Sakai Chemicals) Anti-aging agent A: Irganox 1010 (Ciba Geigy) 〃 B: Antage MB-H (Kawaguchi Chemical) Carbon: Seast 3H (Tokai Carbon) Table From the results shown in Fig. 1, it can be understood that the products according to Examples 1 to 8 are more satisfactory in whitening prevention effect, kneading processability, etc. than others.

〔The invention's effect〕

Since the present invention is configured as described above, the kneading workability is improved and the whitening phenomenon is prevented. Therefore, according to the present invention, it is possible to obtain an electric wire / cable having good tracking resistance without deteriorating the commercial value.

[Brief description of drawings]

The drawings are perspective views of electric wires and cables according to the present invention. P ... Electric wire / cable, 1 ... Conductor, 2 ... Insulator, 3 ... Insulated core wire, 4 ... Outer sheath.

Claims (2)

[Claims] 1. The following (a), (b) and (c) are mixed within respective parts by weight, and a total amount of 100 parts by weight is treated with dioleyl phosphate or distearyl phosphate on the surface. A flame-retardant resin composition for electric wires / cables, characterized by comprising at least 50 to 200 parts by weight of the metal hydroxide and 0.5 to 4 parts by weight of a fatty acid metal salt. (a) Ethylene ethyl acrylate: 59 to 89 parts by weight (b) Ultra low density or linear low density polyethylene: 10 to 30
Parts by weight (c) Grafted product of linear low-density polyethylene or ethylene ethyl acrylate and maleic anhydride: 1 to 20 parts by weight 2. A flame-retardant resin composition for electric wires / cables, characterized by comprising a weather resistance-imparting agent, an anti-aging agent or a coloring agent in the composition according to claim (1).