JPH07116422B2 - Impermeable filler for watertight cable - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water-blocking filler for a watertight cable, which does not excessively adhere to an insulating core, a tying tape, or the like.

2. Description of the Related Art Water-tight cables used in submarines and the like generally include twisted wires of a plurality of insulating cores and a water-blocking filler that is filled between the twisted wires and is also provided on the outer circumference of the twisted wires in some cases. And a cover tape made of this water-blocking filler or a bundling tape wound around the outer circumference of the twisted wire, and a sheath of the outer layer, which realizes a high degree of water-blocking or water-tightness. ing.

Conventionally, as the above-mentioned water-blocking filler, unvulcanized rubber that is close to a putty state has been used in terms of water-tightness and flexibility of the resulting cable.

However, there is a problem that the unvulcanized rubber strongly adheres to the insulating core and the bundling tape due to the heat when the sheath layer is extrusion-molded and vulcanized, and it becomes difficult to take out the insulating core during cable construction. there were.

Means for Solving the Problems The present invention provides a water blocking filler for a watertight cable that overcomes the above problems.

That is, according to the present invention, ethylene / propylene / diene rubber and a non-halogen polymer having a hardness (Shore A) of 75 to 90 are blended at a weight ratio of the former / the latter of 70/30 to 30/70. And a hardness (Shore A) of 50 to 80, which is a gist of a water blocking filler for a watertight cable.

Action With the above-mentioned constitution, it is possible to obtain a water-blocking filler having satisfactory filling property and water-tightness together with the effect of suppressing adhesion based on the non-halogen polymer.

Examples of constituent elements of the invention With respect to the ethylene / propylene / diene rubber used in the present invention, there are no particular limitations on the copolymerization ratio of the components, the type of the diene component, etc., and known ones can be used.

The non-halogen polymer used in the present invention does not contain halogen and has a hardness of 75 Shore A hardness.
~ 90. A crystalline polymer having a hardness within the above range can be used. Examples of non-halogen-based polymers that can be preferably used include ethylene / butene copolymers, ethylene / propylene copolymers, ethylene / vinyl acetate copolymers, and the like.

The water-blocking filler of the present invention comprises a blend of ethylene / propylene / diene rubber and a non-halogen polymer. The blending ratio of ethylene / propylene / diene rubber and non-halogen polymer is 70/30 in terms of the former / latter weight ratio.
A ratio of ~ 30/70 is suitable. If the blending ratio of the non-halogen polymer is less than 30, the adhesion suppressing effect will be poor, and if it exceeds 70, the filling property will be poor, and it will be difficult to obtain a cable excellent in watertightness and flexibility.

The water-blocking filler of the present invention has a Shore A hardness of 50 to 80, preferably 55 to 75. When the hardness is less than 50, the adhesion suppressing effect is poor, and when the hardness is more than 80, the cable having poor filling property and flexibility and watertightness is difficult to obtain.

The water-blocking filler of the present invention is an additive that is usually blended with the rubber composition, such as aluminum hydroxide, magnesium hydroxide, red phosphorus, in the range that maintains the hardness described above.
Zinc borate, antimony trioxide, zinc oxide, clay, talc, carbon black, stearic acid, process oil,
A flame retardant represented by specific examples such as wax, a filler, an antiaging agent, a softening agent and the like may be contained in usual amounts.

The water-blocking filler of the present invention is also used for forming a watertight cable that is usually used in a place where it is likely to be in a moist atmosphere such as a submarine, especially when the insulating material of the insulating core does not contain halogen, It is used to advantage.

EFFECTS OF THE INVENTION The water-blocking filler for watertight cables of the present invention is excellent in watertightness, flexibility, filling property, and the like, and does not strongly adhere to the insulating core or the bundling tape even by heat when the sheath layer is vulcanized. It has characteristics. As a result, the insulating core can be easily taken out, and a watertight cable having excellent workability can be obtained.

Examples Example 1 50 parts of ethylene / propylene / diene rubber (EP21, manufactured by Japan Synthetic Rubber Co., Ltd.) (parts by weight, the same applies hereinafter) and 50 parts of ethylene / butene copolymer (Toughmer A4090, manufactured by Mitsui Petrochemical Co., Ltd.), 5 parts of zinc oxide, 2 parts of stearic acid, 70 parts of aluminum hydroxide (Hijilite H42M, manufactured by Showa Light Metal Co., Ltd.), 5 parts of naphthene-based process oil (Sunsen 4240, manufactured by Nippon Sun Oil Co., Ltd.), and carbon black 10 A water-blocking filler consisting of a mixture with a part was obtained.

Example 2 A water-permeable filler was obtained in the same manner as in Example 1 except that an ethylene / propylene copolymer (X-75, manufactured by Mitsui Petrochemical Co., Ltd.) was used instead of the ethylene / butene copolymer.

Example 3 The mixing amount of ethylene / propylene / diene rubber was 70 parts, and 30 parts of ethylene / vinyl acetate copolymer (Evert K2010, manufactured by Mitsui Petrochemical Co., Ltd.) was used in place of the ethylene / butene copolymer. A water blocking filler was obtained in the same manner as in Example 1 except for the above.

Example 4 A water barrier filler was obtained in the same manner as in Example 2 except that 10 parts of red phosphorus (Novarred # 120, manufactured by Rin Kagaku Co., Ltd.) was additionally compounded.

Example 5 The blending amount of ethylene / propylene / diene rubber was 30 parts, and the blending amount of ethylene / propylene copolymer was 70 parts.
A water blocking filler was obtained in the same manner as in Example 2 except that the parts were used.

Example 6 Instead of aluminum hydroxide, 130 parts of magnesium hydroxide (Kismer 5B, manufactured by Kyowa Chemical Co., Ltd.) was used, and the amount of naphthenic process oil was 8 parts. I got an agent.

Comparative Example 1 A water-permeable filler was obtained in the same manner as in Example 1 except that the ethylene / propylene / diene rubber content was 100 parts and the ethylene / butene copolymer was not added.

Comparative Example 2 The blending amount of ethylene / propylene copolymer was 100 parts,
A water blocking filler was obtained in the same manner as in Example 2 except that ethylene / propylene / diene rubber was not blended.

Evaluation Test [Hardness] The water-blocking fillers obtained in Examples and Comparative Examples were kneaded with two rolls at 70 to 120 ° C. and press-molded at 120 to 130 ° C. for 10 minutes to give a sheet having a thickness of about 3 mm. , JIS K 630 for this sheet
The hardness was measured according to 1.

[Adhesion Suppression] When obtaining a three-core stranded wire using a core insulated with ethylene / propylene / diene rubber by an extrusion method, a water-permeable filler of an example or a comparative example formed in a gap in the center thereof in a string shape. The kneaded product of (1) was formed while being twisted, and was filled between the cores. After that, a sheath layer made of rubber containing no halogen having a predetermined thickness is formed by an extrusion method, and the sheath layer is
It was vulcanized at 0 ° C. for 60 minutes to obtain a watertight cable of 3 × 14 mm ² .

Next, disassemble the obtained watertight cable, check the adhesion state of the insulating layer of the core and the water-blocking filler, and if it is easy to peel off (if it is tightly adhered but not adhered, weakly adhered easily The ones that can be peeled off) were evaluated as ○, and the ones that were difficult to peel off were evaluated as ×.

[Airtightness] For the purpose of evaluating watertightness, filling property and flexibility, the watertight cable 3m obtained above is bent to 100 times the cable diameter, and nitrogen gas is blown from one end thereof at a pressure of 152 mmAq. The nitrogen gas flowing out from the end was collected in a graduated cylinder, and the time until the collected amount reached 50 cc was examined. When the time exceeded 1 hour, it was evaluated as ◯, and when it was 1 hour or less, it was evaluated as x.

The results are shown in the table.

Claims (1)

[Claims] 1. An ethylene / propylene / diene rubber and a non-halogen polymer having a hardness (Shore A) of 75 to 90 are blended at a weight ratio of the former / the latter of 70/30 to 30/70. And a hardness (Shore A) of 50 to 80, which is an impermeable filler for watertight cables.