JPS581924A - Method of producing crosslinked polyolefin 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 The present invention relates to a method for producing a silane-grafted crosslinked polyolefin electric wire.

In the production of silane granod crosslinked polyA reflex wires, we use a silane grafted polyolefin obtained by adding a silane compound and a crosslinking agent to a polyolefin base resin, and a catalyst masterbatch obtained by adding a silanol integrated catalyst to a polyolefin base resin. Generally, a two-step manufacturing method is adopted, which consists of a dung bound step in which the dung bound material is blended with the dung bound material, and an extrusion step in which the dung bound obtained by this process is fed into an extruder and kneaded and extruded.

In this conventional method, the silane-grafted polyolenoin and the catalyst masterbatch are manufactured and stored separately, and a bounding process for blending them and storage space for this compound are required, resulting in the following problems.

0 Processing costs will increase.

■ Keep! ! Sometimes moisture can be absorbed and partial crosslinking begins. (Storage time is obtained.

■ Requires storage space.

■ Silane volatilizes, causing unevenness in the degree of crosslinking.

■ Compound zero is generated for both the grafted polyolefin and the catalyst masterbatch.

■ High probability of contamination with tribute.

■ There is a possibility of inhalation and scattering of silane, so the health and safety conditions are not good.

The present invention provides a method for producing a crosslinked polyolefin electric wire that overcomes the problems of the prior art described above.

An embodiment of the present invention will be described with reference to FIGS. 1 and 2.

A delivery tube 1, an extruder 2, a hot water tank 3, a take-up tube 4, and a winder 5 are arranged in series.

A stirrer 6 is installed on a stand 60 in close proximity to the hopper 21 of the extruder 2.The stirrer 6 is a high-shear mixer, such as a Henschel mixer, and the polyolefin resin supplied therein is Equipped with a preheating mechanism for preheating.

A storage tank 8 is connected to the stirrer 6 via a weighing mechanism 7.

At the same time, the polyolefin resin P in the raw material container 9 is sucked through the feed pipe 10 by the loader 11.
It is stored in a storage tank 8.

A fixed amount of resin is supplied from the storage tank 8 into the stirrer 6 by the weighing mechanism 7.

On the other hand, the stirrer 6 is connected to a device f 2 Q for supplying additives such as a silane compound, a silanol condensation catalyst, and a crosslinking agent.

This additive supply device can be installed not only as one as shown in the figure, but also as a plurality as illustrated by the dotted line.

Note that, if necessary, the additive supply device may be attached with a lightening mechanism.

Therefore, each additive may be supplied as a mixture from one supply device, or may be supplied individually from separate supply devices.

The resin P) is preheated in the stirrer 6 and stirred together with the additives, so that the resin P is forcibly impregnated with the additives.

In the present invention, it is important that the stirrer 6 is equipped with a preheating mechanism.

That is, (1) First, heat the temperature at 40 to 90°C.
Preheat within the range of 5 to 50 minutes. (Secondly, addi- tives are supplied to this preheated resin, and
The process involves a step of forcibly impregnating the mixture by stirring the mixture at 0° C. for 50 minutes.

The compound thus forcibly impregnated is transferred to the input pipe 6'.
After that, it is put into the small collar 21 of the extruder 2, and extrusion molding is performed.

This extrusion geometry 2 is slurry l-length/screw diameter-18
Appropriately is a melon with a thickness of about 35 to 30 cm, and the generation of reactive groups and the initiation of grafting with silane occur simultaneously during melting, kneading, and metering.

Next, the circumference of the conducting wire W1 passing through the crosshead 22 of the extruder is coated with silane granodized polyolefin to form a coated conducting wire W2.

The coated conductive material W 2 is slowly cooled through a hot water tank 3 and crosslinked, and is wound up by a winding machine 5 via a winding machine 4 .

As explained above, the present invention provides a single stirrer.
(Additives such as silane compounds, silanol condensation catalysts, and cross-linking agents are forcibly impregnated into preheated polyolefin to form a compound, which is then directly introduced into an extruder and melted and kneaded in the extruder to form a silane-grafted polyolefin. This method provides a one-step method in which the conductive wire is coated by extrusion and cross-linked while being slowly cooled in a post-forming water tank, and has the following remarkable effects compared to the conventional two-step method. Qin.

(1) Various additives and polyolefins are compounded immediately before being introduced into the extruder, and then introduced directly into the extruder. This eliminates variations in the degree of crosslinking caused by silane volatilization, and improves the physical properties of the wire (tensile strength , elongation properties, heat deformation properties, etc.) are significantly improved.

In addition, partial crosslinking during compound storage is eliminated, and the product appearance is greatly improved.

(2) Since the additive is supplied into the preheated polyolefin and forced impregnation is performed, the additive is uniformly and effectively impregnated into the polyolefin, and the degree of crosslinking is greatly improved.

(3) Since crosslinking is performed in a hot water bath that also serves as cooling, this also improves the degree of crosslinking.

(4) Since compounding is performed in one operation, there is no loss of compound, there is no danger of foreign matter contamination, and there is no inhalation or scattering of silane.

(5) Since the process from compounding to crosslinking is carried out in a series, storage space can be minimized, manufacturing efficiency can be greatly improved, and processing costs can be reduced.

[Brief explanation of drawings]

FIGS. 1 and 2 show an embodiment of the manufacturing equipment for carrying out the present invention, and FIG. 1 is an explanatory diagram showing the entire line;
FIG. 2 is an explanatory diagram showing only the main parts around the extruder. 1: Delivery machine, 2: Extrusion machine, 3: Hot water tank, 4: Taking machine, 5
: Winder, 6: Stirrer, 7: Weighing mechanism, 8: Storage tank, 9: Raw material container, P: Polyolefin resin, 20: Additive supply device.

Claims (1)

[Claims] A stirrer is installed near the extruder, and a supply of additives such as a silane compound, a silanol synthesis catalyst, and a crosslinking agent is connected to this stirrer, and a polyolefin storage tank is also connected via a weighing device 1141, and the above-mentioned stirring The polyolefin preheated in the vessel is impregnated with strong III additives, and the resulting filtrate is directly introduced into the extruder to form a silane-grafted polyolefin, which is extruded and coated on the conductor wire, and then placed in a hot water bath. 1. A method for producing a crosslinked polyolefin electric wire, which comprises crosslinking the wire while slowly cooling the wire.