JPS58174429A - Filling composition for communication cable - Google Patents

Abstract

PURPOSE:To provide the titled composition having excellent dripping characteristics, good water-proofing property, electrical property, etc., and agreeable cost, supply stability, etc., by compounding polybutene with synthetic wax and atactic polypropylene. CONSTITUTION:The objective composition is prepared by compounding (A) 100pts.wt. of a polybutene having a number-average molecular weight of 200- 2,400 with (B) 5-50pts.wt. of a synthetic wax having a number-average molecular weight of 500-5,000 (preferably Fischer-Tropsch wax) and (C) 5-50pts.wt. of an atactic polypropylene having a number-average molecular weight of 5,000-50,000.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a filling composition for communication cables, and more specifically, the present invention relates to a filling composition for communication cables, and more specifically, it is characterized by blending polybutene with a predetermined amount of synthetic wax and atactic polypropylene as essential components, and which has excellent various performances. The present invention relates to a filling composition for communication cables.

BACKGROUND OF THE INVENTION When a communication cable, particularly a communication cable for underground wiring, is damaged or deteriorated in its sheath or connection point, water will enter there and deteriorate the transmission characteristics of the cable. Furthermore, if there are pinholes or the like in the cable insulator, water will cause the insulation to deteriorate, which may eventually lead to a short circuit and a disconnection accident, which often occurs.

Therefore, the development of waterproof communication cables has been promoted as a means of preventing line failures due to water intrusion into the cables, and communication cables filled with a jelly-like substance have come to be widely used. Jelly-like substances for filling cables include petroleum jelly such as petrolatum, polyethylene,
Polybutene is commonly used as a filler for communication cables, especially thick cables with 2,400 to 3,000 core wires in pairs.
It does not meet all the requirements such as electrical properties, dripping properties, melting point, consistency, and workability, and currently, imported trolatum is used as a filling material for such thick communication cables. However, there were also problems in terms of price and supply stability.

Therefore, the present inventors have conducted repeated research to solve the problems of the above-mentioned conventionally known materials for filling communication cables.
The present invention has now been completed.

The present invention satisfies various performances such as waterproof properties, electrical properties, dripping properties, melting point, consistency, and workability, and among them, has particularly excellent dripping properties, and also has communication without problems in terms of price and supply stability. The object is to provide a filling composition for cables, in particular for thick communication cables.

That is, the present invention comprises (A) 100 parts by weight of polybutene having a number average molecular weight of 200 to 2,400, (B) 5 to 5 parts by weight of a synthetic wax having a number average molecular weight of 500 to 5,000, and (0 ) A filling composition for communication cables is provided, which contains 5 to 50 parts by weight of atactic polynolopyrene having a number average molecular weight of 5,000 to 50,000 as an essential component.

Hereinafter, the filling composition for communication cables according to the present invention will be explained in more detail.

The polybutene ((A) component 2.) referred to in the present invention has a number average molecular weight of 200 to 2,400, preferably 500 to 1,5
00, and generally commercially available polybutenes can be used. Furthermore, hydrogenated polybutene obtained by hydrogenating polybutene using a known method such as a nickel or nickel molybdate catalyst can also be used as component (A).

If the component (A) has a number average molecular weight of less than 200, the composition will have a high consistency and become too soft, and if the component (A) has a number average molecular weight of more than 2,400, the melt viscosity of the composition will increase. This is not preferable because it impairs workability. Moreover, when component (A) is not used, the composition becomes too hard and the electrical properties and waterproof properties become insufficient, which is not preferable.

The synthetic wax (component (B)) in the present invention has a number average molecular weight of 500 to 5,000, preferably 500 to 3,000.
0. ■) As a component, specifically, polyolefin wax obtained by homopolymerization or copolymerization of ethylene and proplene, and Fischer-Trozosch wax, which is a by-product during the production of synthetic hydrocarbons by the Fischer-Trozosch process, can be used. However, among them, polyethylene wax and Fischer-Trozosch wax are preferred, and Fischer-Trozosch wax is preferred.
Trozoswax is highly preferred. If the number average molecular weight of component (B) is less than 500, the melting point of the composition will be low and the consistency will be too high.If the component (B) has a number average molecular weight of more than 5,000, the melt viscosity of the composition will be too high. This is not preferable because it impairs workability.

The blending amount of component (B) is 5 to 50 parts by weight, preferably 10 to 35 parts by weight, and preferably 13 to 30 parts by weight per 100 parts by weight of component (A). If component (B) is not used, or if the amount of component (B) is less than the above range, the melting point of the composition will be low and the consistency will be high; If it exceeds the above range, the melting point of the composition will become too high, which is not preferable.

The atactic polynolopyrene ((C') component) in the present invention has a number average molecular weight of 5,000 to 50,000,
Preferably it has 20,000 to 30,000. If the number average molecular weight is less than 5,000, the consistency of the composition will be too small.
If it exceeds 0,000, the compatibility with other components becomes poor and the composition becomes non-uniform, which is not preferable.

The blending amount of component (2) is 5 to 50 parts by weight, preferably 10 to 35 parts by weight, and more preferably 13 to 30 parts by weight per 100 parts by weight of component (A). If component (C) is not used, or if the amount of component (0) is less than the above range, the waterproof properties of the composition will decrease and the penetration will also decrease, which is not preferable. If the blending amount of the components exceeds the above range, the melting point of the composition will increase, the melt viscosity will increase, and workability will deteriorate, which is not preferable.

In the composition of the present invention, the essential components (A) to (
In addition to C), known additives such as antioxidants may be added as necessary. The amount of these known additives added is arbitrary, but it is usually preferably 5 parts by weight or less per 100 parts by weight of the composition.

Further, the method of blending the essential components and additives is arbitrary, and known methods and techniques can be applied.

Hereinafter, the present invention will be explained in more detail with reference to Examples and Comparative Examples. However, the following examples do not limit the present invention in any way. The performance evaluation method for each composition is as follows.

<Electrical properties> tan δ, ■I MH2: Measured by J input SC2101 (25°C).

It is preferable that it is 0.15% or less. Delicious.

ε, ■l MHz: Measured by J Engineering SC2101 (25°C).

It is preferable that it is 2.30 or less. Yes.

<Dripping characteristics> Measured using J-Ko SK 2220 oil separation test method.

, 1. :, 1 72°C 0 hours for 1 hour, 0.5% for 77 degrees Celsius hours
The following are preferred.

Melt point Measured by J Engineering S K 2235.

The temperature is preferably 95°C or higher.

Kucho degree〉 Measured using J Engineering SK 2235 (25°C).

It is preferable that it is 40-60.

Waterproof properties> Shrinkage rate was measured from 140°C to room temperature (25°C) using ASTM D 1168 method A.

Those with a shrinkage rate of less than 10 inches were evaluated as good, and those with a shrinkage rate of 10 inches or more were evaluated as poor.

Example 1 100 parts by weight of polybutene with a number average molecular weight of 750
°C, add 21 parts by weight of Fischer-Trogsch wax with a number average molecular weight of 750, mix the two well, and then heat the mixture to 150 °C and add Attack wax with a number average molecular weight of 25,000. Chic polypropylene 2
Add 1 part by weight, stir well at 150°C for (3) minutes,
A homogeneous "coconut solution" of the three components was obtained.Then, this mixed solution was cooled at room temperature for more than 5 hours to obtain a filling composition for communication cables.Performance evaluation of this composition (electrical properties, dripping properties, melting point , consistency, waterproof properties) are shown in Table 1.

Examples 2-4 (a) polybutene, (B) synthetic wax and (C)
A filling composition for communication cables was obtained using the atactic polypropylene shown in Table 1 in the amount shown in Table 1, and in the same manner as in Example 1 except for the above. Table 1 shows the results of performance evaluation of the obtained composition.

Comparative Examples 1 to 3 For comparison, (B) a case in which synthetic wax is not used (Comparative Example 1), (C) a case in which atactic polypropylene is not used (Comparative Example 2), and (B) a case in which petroleum-based wax is used instead of synthetic wax. In the case of using wax (purified microcrystalline wax) (Comparative Example 3), a composition was obtained in the same manner as in Example 1 except for the substances and amounts shown in Table 1. Table 1 shows the results of the performance evaluation.

As is clear from Table 1, the communication cable filling compositions of Examples 1 to 3 according to the present invention exhibited excellent performance in all of electrical properties, dripping properties, melting points, consistency, and waterproof properties.

On the other hand, Comparative Example 1 was a composition that did not use (B) synthetic wax, and although the electrical properties and waterproof properties were good, the performance was insufficient in dripping properties, melting point, and consistency.

Comparative Example 2 is a composition in which (C) atactic polypropylene is not used, and although the electrical properties are good, the performance is insufficient in other dripping properties, melting point, consistency, and waterproof properties.

Comparative Example 3 is a composition that uses purified microcrystalline wax, which is a petroleum-based wax, instead of the synthetic wax in (■), and although it has good electrical properties, melting point, consistency, and waterproof properties, it is difficult to use for thick communication cables. In the dripping characteristic test, which is particularly important, oil separation occurred at 72°C for 24 hours, which was inappropriate.

Claims (1)

[Claims] 1. (A) polybutene with a number average molecular weight of 200 to 2,400, ioo parts by weight, (B) synthetic wax with a number average molecular weight of 500 to 5,000, 5 to 50 parts by weight, and (C) 5 to 50 parts by weight of atactic polypropylene having a number average molecular weight of 5,000 to 50,000, as essential components.