JPH09208764A - Flame-retardant resin composition and cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the above composition excellent in productivity, watertightness, pick finding capability and flame retardancy, and free from concern for toxic gas production when burned, and obtain a cable by using this composition. SOLUTION: This resin composition comprises 100 pts.wt. of an ethylene- propylene rubber, 300-500 pts.wt. of aluminum hydroxide and 50-80 pts.wt. of a mineral oil-based softening agent (pref. paraffin-or naphthene-based process oil). The other objective cable is obtained by covering this composition around a wire core or wire core bundle composed of a plurality of these wire cores each of which is made by coating a conductor 1 with a nonconductor 2.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a flame-retardant resin composition and a cable.

[0002]

2. Description of the Related Art A watertight cable that prevents water from entering is used as a cable used in ships and the like.
In addition, as the cable, electrical stability, flexibility,
Many twisted cables with excellent space factor are used. In such a cable, a coating layer is formed as an interposition around a wire core bundle including a plurality of wire cores (cores) each including a conductor and an insulator coated on the outer periphery of the conductor. Conventionally, tapes made of acrylic fiber or the like, or water blocking tapes made of yarn or polybutene, compounds of vinyl chloride resin, polybutene or polyethylene terephthalate resin, etc. have been used as materials for forming cables.

[0003]

However, when a cable having an interposition is manufactured by using a tape or a yarn, the tape or the like is wound around or attached to the conductor during the twisting, so that the manufacturing speed of the cable is slow. There was a problem. In addition, these tapes and the like have a problem that a gap is likely to remain around the wire core or the wire bundle and the watertightness of the cable is poor. Furthermore, when a cable with a resin such as polybutene or polyethylene terephthalate is extrusion coated around the wire core and these are interposed, the resin is removed from the cable end when the cable end is exposed for wiring. There was a problem that it was difficult to do. This is because the resin has tackiness. Further, since the cable having the vinyl chloride resin as an intermediary contains a halogen element, there is a possibility that harmful gas such as hydrochloric acid may be released during combustion. Furthermore, acrylic fibers, polybutene, and polyethylene terephthalate resins are inferior in flame retardancy.

The present invention has been made in view of the above circumstances, and uses a composition which is excellent in productivity, watertightness, dischargeability and flame retardancy and which does not generate harmful gas during combustion, and the composition. It is an object to provide a cable that has been used.

[0005]

The flame-retardant resin composition of the present invention comprises 100 parts by weight of ethylene-propylene rubber, 300 to 500 parts by weight of aluminum hydroxide, and a mineral oil-based softening agent 5.
The composition is composed of 0 to 80 parts by weight.

The mineral oil-based softening agent is preferably a paraffin-based or naphthene-based process oil.

The cable of the present invention comprises 100 parts by weight of ethylene-propylene rubber and 300 to 50 aluminum hydroxide.
A composition comprising 0 parts by weight and 50 to 80 parts by weight of a mineral oil-based softening agent is provided on a core or a core bundle in which a conductor is coated with an insulator.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The flame-retardant resin composition of the present invention comprises 100 parts by weight of ethylene-propylene rubber, 300 to 500 parts by weight of aluminum hydroxide, and 50 to 80 parts of a mineral oil softener.
It consists of parts by weight.

The above-mentioned ethylene-propylene rubber is a copolymer mainly composed of ethylene units and propylene units, and typical examples thereof include copolymers of ethylene and propylene, ethylene, propylene, dicyclopentadiene and the like. It is a terpolymer such as a diene monomer. As the ethylene-propylene rubber (hereinafter sometimes referred to as EPDM), commercially available products can be used.

Aluminum hydroxide imparts flame retardancy to the composition. Aluminum hydroxide is blended at a ratio of 300 to 500 parts by weight with respect to 100 parts by weight of ethylene-propylene rubber. If it is less than 300 parts by weight, the flame retardancy of the composition is not improved, and if it exceeds 500 parts by weight,
Extrudability is reduced. Further, the composition of the present invention containing a large amount of inorganic aluminum hydroxide does not exhibit tackiness. Therefore, the cable output property is excellent.

The mineral oil type softening agent is an additive which improves the processability of the mixture of EPDM and aluminum hydroxide, and is an oily substance at -15 ° C. As an example,
Examples include paraffinic or naphthenic process oils. More specifically, as a paraffin-based process oil, Sunpar manufactured by Nippon Sun Oil Co., Ltd.
However, as a naphthene-based process oil, there is Koumorex manufactured by Nippon Oil Co., Ltd. The paraffin-based or naphthene-based process oil is excellent in compatibility with EPDM and is also excellent in various properties such as extrudability, low temperature properties, stain resistance, and aging resistance.

As the mineral oil type softening agent, an oily one having a kinematic viscosity of 20 to 500 cst (centistokes) at 40 ° C. is preferable. If it is less than 20 cst, there is a problem that slippage is likely to occur during kneading.
If it exceeds 00 cst, there is a problem that there is no fluidity and the compounding time becomes long.

The mineral oil type softening agent is 100 parts by weight of ethylene-propylene rubber and 300 to 500 of aluminum hydroxide.
Part by weight to reduce the heat generation during kneading of the mixture and to help disperse the aluminum hydroxide,
It has the effect of improving the processability such as improving the extrusion processability of the composition. Further, it improves mechanical properties such as elasticity and tensile strength of the composition.

The mineral oil type softening agent is mixed in an amount of 50 to 80 parts by weight with respect to 100 parts by weight of ethylene-propylene rubber. If the blending amount is less than 50 parts by weight, the above-mentioned processability improving effect is poor, and if it exceeds 80 parts by weight, the tackiness of the composition is increased, and there is a problem that it is difficult to remove it at the time of dispensing.

A mixture of ethylene-propylene rubber, aluminum hydroxide and a mineral oil-based softening agent can be kneaded by a mixing roller, an extruder, a Banbury mixer or the like and supplied to a desired application.

The resin composition of the present invention contains ethylene-propylene rubber, aluminum hydroxide and a mineral oil-based softening agent as essential components, but other additives can be further added if necessary. Examples of such additives include processing aids such as dyes, pigments and lubricants, fillers, antioxidants, vulcanization accelerators, vulcanizing agents and the like.

FIG. 1 is a cross-sectional view of an embodiment of the electric cable of the present invention, in which the composition of the present invention comprises a plurality of cores in which a conductor 1 is covered with an insulator 2. It is provided on (around) the bundle. As a material forming the insulator 2, an electrically insulating material containing no halogen element such as natural rubber, butyl rubber, or polyethylene is preferable. The composition of the present invention is provided around a wire core composed of a conductor 1 and an insulator 2 coated on the outer periphery of the conductor 1 to form an interposer 3, which is used during a sheath (protective coating) operation. Heat insulation effect, external damage prevention effect, press the wire bundle (wire core group),
Shows effects such as imparting watertightness. Further, the composition of the present invention exhibits excellent adhesion to the insulator 2 composed of natural rubber or the like. Since the composition of the present invention can be coated by extrusion around the core, the core is reliably coated by the composition of the present invention. Therefore, the cable of the present invention has excellent watertightness and is suitable as a marine cable or the like. Providing a lead at the end of the cable of the present invention is useful as a cable for wiring such as a switchboard. Since the cable of the present invention can be made to contain no halogen element, there is no risk of generating harmful gas during combustion.

In the cable of the present invention, the outer periphery of the conductor 1 is extrusion-coated with an electrically insulating material to form an insulator 2, and a plurality of cores composed of the conductor 1 and the insulator 2 are twisted together to obtain a core. A method of forming a coating layer 3 by extrusion coating the composition of the present invention on the outer circumference of a bundle or between wire cores, winding a cloth tape or the like on the outer circumference of the obtained wire rod, and providing a sheath on the outer side thereof. Can be manufactured by

[0019]

Hereinafter, the present invention will be described in detail. In the following Examples and Comparative Examples, all parts mean parts by weight. A sample for clarifying the relationship between the blending ratio and the oxygen index, Mooney viscosity, etc. was prepared as follows. A mixture obtained by mixing 100 parts of ethylene-propylene rubber (EPDM) with aluminum hydroxide fine powder and an oily process oil mixed in different amounts was supplied to a kneading roller and kneaded. The kneaded product was compression-molded to prepare required test pieces. The process oil is Sunpar 2
280 was used.

The oxygen index and Mooney viscosity were measured as follows. Oxygen index (O.I.): Measured by the test method of JIS K-7201. The minimum oxygen concentration required for the test piece to continue burning is shown in Table 1 in volume%. Mooney viscosity: Measured by the unvulcanized rubber physical test method of JIS K6300. The measurement results of oxygen index and Mooney viscosity are shown in Table 1 together with the compounding ratio.

[0021]

[Table 1]

-Examples 1 to 3 and Comparative Examples 1 to 3-From Comparative Example 1 in Table 1, when 200 parts of aluminum hydroxide was used with respect to 100 parts of EPDM, the oxygen index was low and the flame retardancy was poor. Also, from Comparative Example 2, it can be seen that when the aluminum hydroxide content is 600 parts, the Mooney viscosity is too high and extrusion molding is difficult. From Comparative Example 3, it can be seen that when the process oil is 20 parts with respect to 100 parts of EPDM, the Mooney viscosity is too high and extrusion molding is difficult. EPDM1
Aluminum hydroxide is 350 to 4 with respect to 00 parts by weight.
The compositions of Examples 1 to 3, in which 00 parts by weight and the process oil are mixed in a ratio of 50 to 80 parts by weight, have a high oxygen index of 30 to 36, excellent flame retardancy, and a sufficiently low Mooney viscosity. It can be seen that the extrusion moldability is excellent.

-Example 1, Comparative Examples 4 to 7-Next, a cable having the coating layer 3 made of the composition of Example 1 as an intervening member was prepared, and the performance of the cable such as watertightness was clarified. As a comparative example, a water absorbing tape, a water blocking tape,
A cable having a vinyl chloride resin and a polybutene resin as an interposer was prepared.

Cables of Example 1 and Comparative Examples 6 to 7: FIG.
As shown in Fig. 7, the outer circumference of the conductor 1 is extruded and coated with polyethylene to form the insulator 2, and seven wire cores are twisted together, and then on the wire core bundle composed of the seven wire cores (outer circumference). Then, the composition of Example 1 above, a vinyl chloride resin or a polybutene resin was extrusion-coated and provided with the coating layer 3 interposed, and the sheath 4 was formed on the outer periphery of the coating layer 3. Cables of Comparative Examples 4 to 5: Acrylic fiber tape (having water absorbency) and polybutene water blocking tape are wound to form the interposition 3 when the wire cores are twisted in the same manner as described above, Then, the sheath 4 was formed to form the structure.

The performance was measured by the following method. Outputability of cable: A sheet-shaped material of the material forming the interposition 3 is placed on a polyethylene sheet (PE sheet), a load of 5 kg is applied to the sheet-shaped material and left at room temperature for 24 hours, and then the sheet-shaped material is peeled off. did. The release property was simply evaluated by the amount of resin remaining on the PE sheet without peeling from the PE sheet. The cable output property was judged to be bad when the amount of residual resin was large. Finally, the cable was actually manufactured, and it was judged from the easiness of the cable to be exposed at the end of the cable whether the output was good or bad. Water tightness: Water pressure was applied to one end of the cable for 15 minutes, and the upper limit water pressure at which water did not leak from the other end was measured. Table 2 shows the results of performance measurement such as the type of material forming the interposition and watertightness.

[0026]

[Table 2]

As shown in Table 2, the cable of Example 1 having the composition of 100 parts of EPDM, 350 parts of aluminum hydroxide and 80 parts of process oil was excellent in watertightness of 110 kg / cm ² . Further, the cable of Example 1 is excellent in flame retardance, and its production speed is 3 times with the use of the tape.
It was able to be made larger than the case of the cable (Comparative Examples 4 to 5). In addition, from the cable end of Example 1,
The coating layer 3 could be easily removed. In other words, the composition of Example 1 was excellent in squeezing property.

[0028]

As described above, the flame-retardant resin composition of the present invention is a composition which is excellent in productivity, dischargeability and flame retardancy, and which does not generate harmful gas during combustion. The cable provided with the composition on the core or the bundle of cores can be efficiently manufactured, is excellent in flame retardancy and watertightness, and does not generate harmful gas during combustion.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a cable according to an exemplary embodiment of the present invention.

[Explanation of symbols]

1 ... Conductor, 2. Insulator, 3 ... Coating layer (intervening), 4
··sheath

Continuation of front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display area C08L 91:00)

Claims (3)

[Claims] 1. A flame-retardant resin composition comprising 100 parts by weight of ethylene-propylene rubber, 300 to 500 parts by weight of aluminum hydroxide, and 50 to 80 parts by weight of a mineral oil-based softening agent. 2. The flame-retardant resin composition according to claim 1, wherein the mineral oil-based softening agent is a paraffin-based or naphthene-based process oil. 3. A cable in which the composition according to claim 1 is provided on a core or a core bundle in which a conductor is coated with an insulator.