JPS6039712A - Method of producing foamable polypropylene insulated wire - 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 a method for manufacturing a foamed polypropylene insulated wire.

In recent years, coaxial cables for computers have been required to be thinner and have better heat resistance, and foamed polyethylene is generally used for this purpose, but it is inferior in toughness and heat resistance. This toughness and heat resistance can be improved by foaming polyethylene and then crosslinking it by electron beam irradiation, but this requires a lot of man-hours.

For this reason, we focused on polypropylene and attempted chemical foaming. In other words, we produced polypropylene-based insulated wires that were foamed using a chemical foaming agent, but since the melting temperature of polypropylene is high if the chemical foaming agent that is commonly used in the past is used as it is, it was necessary to uniformly disperse the chemical foaming agent. There was a drawback that foaming occurred in one molecule during the kneading process.

The present invention has been made in view of the above points, and it is an object of the present invention to provide a method for manufacturing a foamed polypropylene-based insulated wire that makes it possible to prevent partial foaming.

[Summary of the invention]

That is, the present invention is a method for manufacturing a polypropylene insulated wire foamed using a chemical foaming agent, which is characterized in that the chemical foaming agent is treated with a titanate coupling agent. This makes it possible to increase the decomposition temperature of

〔Example〕

In this example, a polypropylene insulated wire was produced by foaming a chemical foaming agent by treating it with a titanate coupling agent. By doing this, the decomposition temperature of the chemical blowing agent increases and partial foaming in the extruder is prevented.
A method for producing a foamed polypropylene insulated electric wire that can prevent partial foaming can be obtained.

That is, the chemical blowing agent asodicarbonamide is treated with the same amount of titanate coupling agent, and the treated product is
．． Polypropylene containing 0% by weight (melt flow 9)
Example 1 was a foamed polypropylene insulated wire produced by extruding and coating a conductor with a conductor diameter of 0.65 m/m to a thickness of 0.25 m/m at a constant wire speed.

In addition, polypropylene (Melt Flow 5) Comparan F containing 2.5% by weight of the chemical blowing agent 4,4'-oxyhishenzenesulfonylhydrazide was treated with the same amount of titanate coupling agent. , a thickness of 0.15 n+/i on a conductor with a conductor diameter of 0.50 m/m
Foamed volume L manufactured by extrusion 'a overturning at a constant linear speed of n
Example 2 was an I-pyrene insulated wire.

In examining the characteristics of the foamed polypropylene insulated wire of Example 1.2 manufactured in this way, we used polypropylene (Melt Flow 9) containing 1.0% by weight of the chemical blowing agent Asodicarbonamide F as Comparative Example 1. compound,
A conductor with a thickness of 0.25 m/m on a conductor with a conductor diameter of 0.65 m/m
A foamed polypropylene insulated wire was manufactured by extrusion coating at a constant wire speed.

As shown in the table below, the characteristics of Examples 1 and 2 and Comparative Example 1 are as follows. , Comparative Example 1 has a partially foamed appearance during compounding, and the appearance during extrusion coating is not only problem-free compared to surface roughness, but also has a deviation from the center value of capacitance of the strand (conductor) compared to Comparative Example 1. It is much smaller than that of 1, and
Ta. In this way, the deviation from the center value of wire capacitance in Example 2 was small because partial knitting bubbles were prevented during extrusion m4-, and fine air bubbles were uniformly dispersed and formed. However, partial foaming in the extruder was prevented because the chemical blowing agent was treated with a titanate coupling agent, which increased the decomposition temperature of the chemical blowing agent. Since the bubbles can be uniformly dispersed in this way, it is possible to make the wire thinner, and since polypropylene is used, the heat resistance can be improved.

The chemical blowing agent used may be any ordinary solid blowing agent that can be decomposed by the heat of extrusion to generate gas molecules, and two or more chemical blowing agents may be appropriately blended if necessary. .

The polypropylene is not particularly limited, and may be blended with homopolymers, copolymers, or other polymers such as polyisobutylene and polyethylene as long as they do not impair the properties of the polypropylene.

In addition to these chemical foaming agents and polypropylene, an antioxidant, a metal deactivator, a foaming nucleating agent, and a foaming nucleating agent may also be used as appropriate.

〔Effect of the invention〕

As described above, the present invention makes it possible to increase the decomposition temperature of the chemical blowing agent, thereby preventing partial foaming of the polyethylene material 1 in the extrusion shell. It is possible to obtain foamed polypropylene-based absolute ♀5 and electric wires that can prevent the above.

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Claims (1)

[Claims] (+) A method for producing a polypropylene insulated wire foamed with a chemical foaming agent, the method comprising treating the chemical foaming agent with a titanate coupling agent.